xref: /xnu-11417.101.15/bsd/net/dlil.c (revision e3723e1f17661b24996789d8afc084c0c3303b26)

/*
 * Copyright (c) 1999-2025 Apple Inc. All rights reserved.
 *
 * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
 *
 * This file contains Original Code and/or Modifications of Original Code
 * as defined in and that are subject to the Apple Public Source License
 * Version 2.0 (the 'License'). You may not use this file except in
 * compliance with the License. The rights granted to you under the License
 * may not be used to create, or enable the creation or redistribution of,
 * unlawful or unlicensed copies of an Apple operating system, or to
 * circumvent, violate, or enable the circumvention or violation of, any
 * terms of an Apple operating system software license agreement.
 *
 * Please obtain a copy of the License at
 * http://www.opensource.apple.com/apsl/ and read it before using this file.
 *
 * The Original Code and all software distributed under the License are
 * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
 * Please see the License for the specific language governing rights and
 * limitations under the License.
 *
 * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
 */
/*
 * NOTICE: This file was modified by SPARTA, Inc. in 2005 to introduce
 * support for mandatory and extensible security protections.  This notice
 * is included in support of clause 2.2 (b) of the Apple Public License,
 * Version 2.0.
 */
#include <stddef.h>
#include <ptrauth.h>

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/malloc.h>
#include <sys/mbuf.h>
#include <sys/socket.h>
#include <sys/domain.h>
#include <sys/user.h>
#include <sys/random.h>
#include <sys/socketvar.h>
#include <net/if_dl.h>
#include <net/if.h>
#include <net/route.h>
#include <net/if_var.h>
#include <net/dlil.h>
#include <net/dlil_sysctl.h>
#include <net/dlil_var_private.h>
#include <net/if_arp.h>
#include <net/iptap.h>
#include <net/pktap.h>
#include <net/droptap.h>
#include <net/nwk_wq.h>
#include <sys/kern_event.h>
#include <sys/kdebug.h>
#include <sys/mcache.h>
#include <sys/syslog.h>
#include <sys/protosw.h>
#include <sys/priv.h>

#include <kern/assert.h>
#include <kern/task.h>
#include <kern/thread.h>
#include <kern/sched_prim.h>
#include <kern/locks.h>
#include <kern/zalloc.h>

#include <net/kpi_protocol.h>
#include <net/kpi_interface.h>
#include <net/if_types.h>
#include <net/if_ipsec.h>
#include <net/if_llreach.h>
#include <net/if_utun.h>
#include <net/kpi_interfacefilter.h>
#include <net/classq/classq.h>
#include <net/classq/classq_sfb.h>
#include <net/flowhash.h>
#include <net/ntstat.h>
#if SKYWALK
#include <skywalk/lib/net_filter_event.h>
#endif /* SKYWALK */
#include <net/net_api_stats.h>
#include <net/if_ports_used.h>
#include <net/if_vlan_var.h>
#include <netinet/in.h>
#if INET
#include <netinet/in_var.h>
#include <netinet/igmp_var.h>
#include <netinet/ip_var.h>
#include <netinet/tcp.h>
#include <netinet/tcp_var.h>
#include <netinet/udp.h>
#include <netinet/udp_var.h>
#include <netinet/if_ether.h>
#include <netinet/in_pcb.h>
#include <netinet/in_tclass.h>
#include <netinet/ip.h>
#include <netinet/ip_icmp.h>
#include <netinet/icmp_var.h>
#endif /* INET */

#include <net/nat464_utils.h>
#include <netinet6/in6_var.h>
#include <netinet6/nd6.h>
#include <netinet6/mld6_var.h>
#include <netinet6/scope6_var.h>
#include <netinet/ip6.h>
#include <netinet/icmp6.h>
#include <net/pf_pbuf.h>
#include <libkern/OSAtomic.h>
#include <libkern/tree.h>

#include <dev/random/randomdev.h>
#include <machine/machine_routines.h>

#include <mach/thread_act.h>
#include <mach/sdt.h>

#if CONFIG_MACF
#include <sys/kauth.h>
#include <security/mac_framework.h>
#include <net/ethernet.h>
#include <net/firewire.h>
#endif

#if PF
#include <net/pfvar.h>
#endif /* PF */
#include <net/pktsched/pktsched.h>
#include <net/pktsched/pktsched_netem.h>

#if NECP
#include <net/necp.h>
#endif /* NECP */

#if SKYWALK
#include <skywalk/packet/packet_queue.h>
#include <skywalk/nexus/netif/nx_netif.h>
#include <skywalk/nexus/flowswitch/nx_flowswitch.h>
#endif /* SKYWALK */

#include <net/sockaddr_utils.h>

#include <os/log.h>

uint64_t if_creation_generation_count = 0;

__private_extern__ unsigned int if_ref_trace_hist_size = IF_REF_TRACE_HIST_SIZE;

dlil_ifnet_queue_t dlil_ifnet_head;

#if DEBUG
unsigned int ifnet_debug = 1;    /* debugging (enabled) */
#else
unsigned int ifnet_debug;        /* debugging (disabled) */
#endif /* !DEBUG */


static u_int32_t net_rtref;

static struct dlil_main_threading_info dlil_main_input_thread_info;
struct dlil_threading_info *__single dlil_main_input_thread;

static int dlil_event_internal(struct ifnet *ifp, struct kev_msg *msg, bool update_generation);
static int dlil_detach_filter_internal(interface_filter_t filter, int detached);

static int ifnet_lookup(struct ifnet *);
static void if_purgeaddrs(struct ifnet *);

static errno_t ifproto_media_input_v1(struct ifnet *, protocol_family_t,
    struct mbuf *, char *);
static errno_t ifproto_media_input_v2(struct ifnet *, protocol_family_t,
    struct mbuf *);
static errno_t ifproto_media_preout(struct ifnet *, protocol_family_t,
    mbuf_t *, const struct sockaddr *, void *,
    IFNET_FRAME_TYPE_RW_T, IFNET_LLADDR_RW_T);
static void ifproto_media_event(struct ifnet *, protocol_family_t,
    const struct kev_msg *);
static errno_t ifproto_media_ioctl(struct ifnet *, protocol_family_t,
    unsigned long, void *);
static errno_t ifproto_media_resolve_multi(ifnet_t, const struct sockaddr *,
    struct sockaddr_dl *, size_t);
static errno_t ifproto_media_send_arp(struct ifnet *, u_short,
    const struct sockaddr_dl *, const struct sockaddr *,
    const struct sockaddr_dl *, const struct sockaddr *);

static errno_t ifp_if_input(struct ifnet *ifp, struct mbuf *m_head,
    struct mbuf *m_tail, const struct ifnet_stat_increment_param *s,
    boolean_t poll, struct thread *tp);
static void ifp_if_input_poll(struct ifnet *, u_int32_t, u_int32_t,
    struct mbuf **, struct mbuf **, u_int32_t *, u_int32_t *);
static errno_t ifp_if_ctl(struct ifnet *, ifnet_ctl_cmd_t, u_int32_t, void *);
static errno_t ifp_if_demux(struct ifnet *, struct mbuf *, char *,
    protocol_family_t *);
static errno_t ifp_if_add_proto(struct ifnet *, protocol_family_t,
    const struct ifnet_demux_desc *, u_int32_t);
static errno_t ifp_if_del_proto(struct ifnet *, protocol_family_t);
static errno_t ifp_if_check_multi(struct ifnet *, const struct sockaddr *);
#if !XNU_TARGET_OS_OSX
static errno_t ifp_if_framer(struct ifnet *, struct mbuf **,
    const struct sockaddr *, IFNET_LLADDR_T, IFNET_FRAME_TYPE_T,
    u_int32_t *, u_int32_t *);
#else /* XNU_TARGET_OS_OSX */
static errno_t ifp_if_framer(struct ifnet *, struct mbuf **,
    const struct sockaddr *,
    IFNET_LLADDR_T, IFNET_FRAME_TYPE_T);
#endif /* XNU_TARGET_OS_OSX */
static errno_t ifp_if_framer_extended(struct ifnet *, struct mbuf **,
    const struct sockaddr *,
    IFNET_LLADDR_T, IFNET_FRAME_TYPE_T,
    u_int32_t *, u_int32_t *);
static errno_t ifp_if_set_bpf_tap(struct ifnet *, bpf_tap_mode, bpf_packet_func);
static void ifp_if_free(struct ifnet *);
static void ifp_if_event(struct ifnet *, const struct kev_msg *);



static errno_t ifnet_input_common(struct ifnet *, struct mbuf *, struct mbuf *,
    const struct ifnet_stat_increment_param *, boolean_t, boolean_t);
#if DEBUG || DEVELOPMENT
static void dlil_verify_sum16(void);
#endif /* DEBUG || DEVELOPMENT */


static void ifnet_detacher_thread_func(void *, wait_result_t);
static void ifnet_detacher_thread_cont(void *, wait_result_t);
static void ifnet_detach_final(struct ifnet *);
static void ifnet_detaching_enqueue(struct ifnet *);
static struct ifnet *ifnet_detaching_dequeue(void);

static void ifnet_start_thread_func(void *, wait_result_t);
static void ifnet_start_thread_cont(void *, wait_result_t);

static void ifnet_poll_thread_func(void *, wait_result_t);
static void ifnet_poll_thread_cont(void *, wait_result_t);

static errno_t ifnet_enqueue_common(struct ifnet *, struct ifclassq *,
    classq_pkt_t *, boolean_t, boolean_t *);

static void ifp_src_route_copyout(struct ifnet *, struct route *);
static void ifp_src_route_copyin(struct ifnet *, struct route *);
static void ifp_src_route6_copyout(struct ifnet *, struct route_in6 *);
static void ifp_src_route6_copyin(struct ifnet *, struct route_in6 *);


/* The following are protected by dlil_ifnet_lock */
static TAILQ_HEAD(, ifnet) ifnet_detaching_head;
static u_int32_t ifnet_detaching_cnt;
static boolean_t ifnet_detaching_embryonic;
static void *ifnet_delayed_run; /* wait channel for detaching thread */

static LCK_MTX_DECLARE_ATTR(ifnet_fc_lock, &dlil_lock_group,
    &dlil_lck_attributes);

static uint32_t ifnet_flowhash_seed;

struct ifnet_flowhash_key {
	char            ifk_name[IFNAMSIZ];
	uint32_t        ifk_unit;
	uint32_t        ifk_flags;
	uint32_t        ifk_eflags;
	uint32_t        ifk_capabilities;
	uint32_t        ifk_capenable;
	uint32_t        ifk_output_sched_model;
	uint32_t        ifk_rand1;
	uint32_t        ifk_rand2;
};

/* Flow control entry per interface */
struct ifnet_fc_entry {
	RB_ENTRY(ifnet_fc_entry) ifce_entry;
	u_int32_t       ifce_flowhash;
	ifnet_ref_t     ifce_ifp;
};

static uint32_t ifnet_calc_flowhash(struct ifnet *);
static int ifce_cmp(const struct ifnet_fc_entry *,
    const struct ifnet_fc_entry *);
static int ifnet_fc_add(struct ifnet *);
static struct ifnet_fc_entry *ifnet_fc_get(u_int32_t);
static void ifnet_fc_entry_free(struct ifnet_fc_entry *);

/* protected by ifnet_fc_lock */
RB_HEAD(ifnet_fc_tree, ifnet_fc_entry) ifnet_fc_tree;
RB_PROTOTYPE(ifnet_fc_tree, ifnet_fc_entry, ifce_entry, ifce_cmp);
RB_GENERATE(ifnet_fc_tree, ifnet_fc_entry, ifce_entry, ifce_cmp);

static KALLOC_TYPE_DEFINE(ifnet_fc_zone, struct ifnet_fc_entry, NET_KT_DEFAULT);

extern void bpfdetach(struct ifnet *);


extern uint32_t udp_count_opportunistic(unsigned int ifindex,
    u_int32_t flags);
extern uint32_t tcp_count_opportunistic(unsigned int ifindex,
    u_int32_t flags);


#if CONFIG_MACF
#if !XNU_TARGET_OS_OSX
int dlil_lladdr_ckreq = 1;
#else /* XNU_TARGET_OS_OSX */
int dlil_lladdr_ckreq = 0;
#endif /* XNU_TARGET_OS_OSX */
#endif /* CONFIG_MACF */


static inline void
ifnet_delay_start_disabled_increment(void)
{
	OSIncrementAtomic(&ifnet_delay_start_disabled);
}

unsigned int net_rxpoll = 1;
unsigned int net_affinity = 1;
unsigned int net_async = 1;     /* 0: synchronous, 1: asynchronous */

extern u_int32_t        inject_buckets;

void
ifnet_filter_update_tso(struct ifnet *ifp, boolean_t filter_enable)
{
	/*
	 * update filter count and route_generation ID to let TCP
	 * know it should reevalute doing TSO or not
	 */
	if (filter_enable) {
		OSAddAtomic(1, &ifp->if_flt_no_tso_count);
	} else {
		VERIFY(ifp->if_flt_no_tso_count != 0);
		OSAddAtomic(-1, &ifp->if_flt_no_tso_count);
	}
	routegenid_update();
}

#if SKYWALK

static bool net_check_compatible_if_filter(struct ifnet *ifp);

/* if_attach_nx flags defined in os_skywalk_private.h */
unsigned int if_attach_nx = IF_ATTACH_NX_DEFAULT;
unsigned int if_enable_fsw_ip_netagent =
    ((IF_ATTACH_NX_DEFAULT & IF_ATTACH_NX_FSW_IP_NETAGENT) != 0);
unsigned int if_enable_fsw_transport_netagent =
    ((IF_ATTACH_NX_DEFAULT & IF_ATTACH_NX_FSW_TRANSPORT_NETAGENT) != 0);

unsigned int if_netif_all =
    ((IF_ATTACH_NX_DEFAULT & IF_ATTACH_NX_NETIF_ALL) != 0);

/* Configure flowswitch to use max mtu sized buffer */
static bool fsw_use_max_mtu_buffer = false;


static void dlil_detach_flowswitch_nexus(if_nexus_flowswitch_t nexus_fsw);

#include <skywalk/os_skywalk_private.h>

boolean_t
ifnet_nx_noauto(ifnet_t ifp)
{
	return (ifp->if_xflags & IFXF_NX_NOAUTO) != 0;
}

boolean_t
ifnet_nx_noauto_flowswitch(ifnet_t ifp)
{
	return ifnet_is_low_latency(ifp);
}

boolean_t
ifnet_is_low_latency(ifnet_t ifp)
{
	return (ifp->if_xflags & IFXF_LOW_LATENCY) != 0;
}

boolean_t
ifnet_needs_compat(ifnet_t ifp)
{
	if ((if_attach_nx & IF_ATTACH_NX_NETIF_COMPAT) == 0) {
		return FALSE;
	}
#if !XNU_TARGET_OS_OSX
	/*
	 * To conserve memory, we plumb in the compat layer selectively; this
	 * can be overridden via if_attach_nx flag IF_ATTACH_NX_NETIF_ALL.
	 * In particular, we check for Wi-Fi Access Point.
	 */
	if (IFNET_IS_WIFI(ifp)) {
		/* Wi-Fi Access Point */
		if (strcmp(ifp->if_name, "ap") == 0) {
			return if_netif_all;
		}
	}
#else /* XNU_TARGET_OS_OSX */
#pragma unused(ifp)
#endif /* XNU_TARGET_OS_OSX */
	return TRUE;
}

boolean_t
ifnet_needs_fsw_transport_netagent(ifnet_t ifp)
{
	if (if_is_fsw_transport_netagent_enabled()) {
		/* check if netagent has been manually enabled for ipsec/utun */
		if (ifp->if_family == IFNET_FAMILY_IPSEC) {
			return ipsec_interface_needs_netagent(ifp);
		} else if (ifp->if_family == IFNET_FAMILY_UTUN) {
			return utun_interface_needs_netagent(ifp);
		}

		/* check ifnet no auto nexus override */
		if (ifnet_nx_noauto(ifp)) {
			return FALSE;
		}

		/* check global if_attach_nx configuration */
		switch (ifp->if_family) {
		case IFNET_FAMILY_CELLULAR:
		case IFNET_FAMILY_ETHERNET:
			if ((if_attach_nx & IF_ATTACH_NX_FSW_TRANSPORT_NETAGENT) != 0) {
				return TRUE;
			}
			break;
		default:
			break;
		}
	}
	return FALSE;
}

boolean_t
ifnet_needs_fsw_ip_netagent(ifnet_t ifp)
{
#pragma unused(ifp)
	if ((if_attach_nx & IF_ATTACH_NX_FSW_IP_NETAGENT) != 0) {
		return TRUE;
	}
	return FALSE;
}

boolean_t
ifnet_needs_netif_netagent(ifnet_t ifp)
{
#pragma unused(ifp)
	return (if_attach_nx & IF_ATTACH_NX_NETIF_NETAGENT) != 0;
}

static boolean_t
dlil_detach_nexus_instance(nexus_controller_t controller,
    const char *func_str, uuid_t instance, uuid_t device)
{
	errno_t         err;

	if (instance == NULL || uuid_is_null(instance)) {
		return FALSE;
	}

	/* followed by the device port */
	if (device != NULL && !uuid_is_null(device)) {
		err = kern_nexus_ifdetach(controller, instance, device);
		if (err != 0) {
			DLIL_PRINTF("%s kern_nexus_ifdetach device failed %d\n",
			    func_str, err);
		}
	}
	err = kern_nexus_controller_free_provider_instance(controller,
	    instance);
	if (err != 0) {
		DLIL_PRINTF("%s free_provider_instance failed %d\n",
		    func_str, err);
	}
	return TRUE;
}

static boolean_t
dlil_detach_nexus(const char *func_str, uuid_t provider, uuid_t instance,
    uuid_t device)
{
	boolean_t               detached = FALSE;
	nexus_controller_t      controller = kern_nexus_shared_controller();
	int                     err;

	if (dlil_detach_nexus_instance(controller, func_str, instance,
	    device)) {
		detached = TRUE;
	}
	if (provider != NULL && !uuid_is_null(provider)) {
		detached = TRUE;
		err = kern_nexus_controller_deregister_provider(controller,
		    provider);
		if (err != 0) {
			DLIL_PRINTF("%s deregister_provider %d\n",
			    func_str, err);
		}
	}
	return detached;
}

static errno_t
dlil_create_provider_and_instance(nexus_controller_t controller,
    nexus_type_t type, ifnet_t ifp, uuid_t *provider, uuid_t *instance,
    nexus_attr_t attr)
{
	uuid_t          dom_prov;
	errno_t         err;
	nexus_name_t    provider_name;
	const char      *type_name =
	    (type == NEXUS_TYPE_NET_IF) ? "netif" : "flowswitch";
	struct kern_nexus_init init;

	err = kern_nexus_get_default_domain_provider(type, &dom_prov);
	if (err != 0) {
		DLIL_PRINTF("%s can't get %s provider, error %d\n",
		    __func__, type_name, err);
		goto failed;
	}

	snprintf((char *)provider_name, sizeof(provider_name),
	    "com.apple.%s.%s", type_name, if_name(ifp));
	err = kern_nexus_controller_register_provider(controller,
	    dom_prov,
	    provider_name,
	    NULL,
	    0,
	    attr,
	    provider);
	if (err != 0) {
		DLIL_PRINTF("%s register %s provider failed, error %d\n",
		    __func__, type_name, err);
		goto failed;
	}
	bzero(&init, sizeof(init));
	init.nxi_version = KERN_NEXUS_CURRENT_VERSION;
	err = kern_nexus_controller_alloc_provider_instance(controller,
	    *provider,
	    NULL, NULL,
	    instance, &init);
	if (err != 0) {
		DLIL_PRINTF("%s alloc_provider_instance %s failed, %d\n",
		    __func__, type_name, err);
		kern_nexus_controller_deregister_provider(controller,
		    *provider);
		goto failed;
	}
failed:
	return err;
}

static boolean_t
dlil_attach_netif_nexus_common(ifnet_t ifp, if_nexus_netif_t netif_nx)
{
	nexus_attr_t            __single attr = NULL;
	nexus_controller_t      controller;
	errno_t                 err;
	unsigned char          *empty_uuid = __unsafe_forge_bidi_indexable(unsigned char *, NULL, sizeof(uuid_t));

	if ((ifp->if_capabilities & IFCAP_SKYWALK) != 0) {
		/* it's already attached */
		if (dlil_verbose) {
			DLIL_PRINTF("%s: %s already has nexus attached\n",
			    __func__, if_name(ifp));
			/* already attached */
		}
		goto failed;
	}

	err = kern_nexus_attr_create(&attr);
	if (err != 0) {
		DLIL_PRINTF("%s: nexus attr create for %s\n", __func__,
		    if_name(ifp));
		goto failed;
	}
	err = kern_nexus_attr_set(attr, NEXUS_ATTR_IFINDEX, ifp->if_index);
	VERIFY(err == 0);

	controller = kern_nexus_shared_controller();

	/* create the netif provider and instance */
	err = dlil_create_provider_and_instance(controller,
	    NEXUS_TYPE_NET_IF, ifp, &netif_nx->if_nif_provider,
	    &netif_nx->if_nif_instance, attr);
	if (err != 0) {
		goto failed;
	}

	err = kern_nexus_ifattach(controller, netif_nx->if_nif_instance, ifp,
	    empty_uuid, FALSE, &netif_nx->if_nif_attach);
	if (err != 0) {
		DLIL_PRINTF("%s kern_nexus_ifattach %d\n",
		    __func__, err);
		/* cleanup provider and instance */
		dlil_detach_nexus(__func__, netif_nx->if_nif_provider,
		    netif_nx->if_nif_instance, empty_uuid);
		goto failed;
	}
	return TRUE;

failed:
	if (attr != NULL) {
		kern_nexus_attr_destroy(attr);
	}
	return FALSE;
}

static boolean_t
dlil_attach_netif_compat_nexus(ifnet_t ifp, if_nexus_netif_t netif_nx)
{
	if (ifnet_nx_noauto(ifp) || IFNET_IS_INTCOPROC(ifp) ||
	    IFNET_IS_MANAGEMENT(ifp) || IFNET_IS_VMNET(ifp)) {
		goto failed;
	}
	switch (ifp->if_type) {
	case IFT_CELLULAR:
	case IFT_ETHER:
		if ((if_attach_nx & IF_ATTACH_NX_NETIF_COMPAT) == 0) {
			/* don't auto-attach */
			goto failed;
		}
		break;
	default:
		/* don't auto-attach */
		goto failed;
	}
	return dlil_attach_netif_nexus_common(ifp, netif_nx);

failed:
	return FALSE;
}

__attribute__((noinline))
static void
dlil_detach_netif_nexus(if_nexus_netif_t nexus_netif)
{
	dlil_detach_nexus(__func__, nexus_netif->if_nif_provider,
	    nexus_netif->if_nif_instance, nexus_netif->if_nif_attach);
}

static inline int
dlil_siocgifdevmtu(struct ifnet * ifp, struct ifdevmtu * ifdm_p)
{
	struct ifreq        ifr;
	int                 error;

	bzero(&ifr, sizeof(ifr));
	error = ifnet_ioctl(ifp, 0, SIOCGIFDEVMTU, &ifr);
	if (error == 0) {
		*ifdm_p = ifr.ifr_devmtu;
	}
	return error;
}

static inline void
_dlil_adjust_large_buf_size_for_tso(ifnet_t ifp, uint32_t *large_buf_size)
{
	uint32_t tso_v4_mtu = 0;
	uint32_t tso_v6_mtu = 0;

	if (!kernel_is_macos_or_server()) {
		return;
	}

	/*
	 * Note that we are reading the real hwassist flags set by the driver
	 * and not the adjusted ones because nx_netif_host_adjust_if_capabilities()
	 * hasn't been called yet.
	 */
	if ((ifp->if_hwassist & IFNET_TSO_IPV4) != 0) {
		tso_v4_mtu = ifp->if_tso_v4_mtu;
	}
	if ((ifp->if_hwassist & IFNET_TSO_IPV6) != 0) {
		tso_v6_mtu = ifp->if_tso_v6_mtu;
	}

	/*
	 * If the hardware supports TSO, adjust the large buf size to match the
	 * supported TSO MTU size. Note that only native interfaces set TSO MTU
	 * size today.
	 * For compat, there is a 16KB limit on large buf size, so it needs to be
	 * bounded by NX_FSW_DEF_LARGE_BUFSIZE. Note that no compat interfaces
	 * set TSO MTU size today.
	 */
	if (SKYWALK_NATIVE(ifp)) {
		if (tso_v4_mtu != 0 || tso_v6_mtu != 0) {
			*large_buf_size = MAX(tso_v4_mtu, tso_v6_mtu);
		} else {
			*large_buf_size = MAX(*large_buf_size, sk_fsw_gso_mtu);
		}
		*large_buf_size = MIN(NX_FSW_MAX_LARGE_BUFSIZE, *large_buf_size);
	} else {
		*large_buf_size = MIN(NX_FSW_DEF_LARGE_BUFSIZE, *large_buf_size);
	}
}

static inline int
_dlil_get_flowswitch_buffer_size(ifnet_t ifp, uuid_t netif, uint32_t *buf_size,
    bool *use_multi_buflet, uint32_t *large_buf_size)
{
	struct kern_pbufpool_memory_info rx_pp_info;
	struct kern_pbufpool_memory_info tx_pp_info;
	uint32_t if_max_mtu = 0;
	uint32_t drv_buf_size;
	struct ifdevmtu ifdm;
	int err;

	/*
	 * To perform intra-stack RX aggregation flowswitch needs to use
	 * multi-buflet packet.
	 */
	*use_multi_buflet = NX_FSW_TCP_RX_AGG_ENABLED();

	*large_buf_size = *use_multi_buflet ? NX_FSW_DEF_LARGE_BUFSIZE : 0;
	/*
	 * IP over Thunderbolt interface can deliver the largest IP packet,
	 * but the driver advertises the MAX MTU as only 9K.
	 */
	if (IFNET_IS_THUNDERBOLT_IP(ifp)) {
		if_max_mtu = IP_MAXPACKET;
		goto skip_mtu_ioctl;
	}

	/* determine max mtu */
	bzero(&ifdm, sizeof(ifdm));
	err = dlil_siocgifdevmtu(ifp, &ifdm);
	if (__improbable(err != 0)) {
		DLIL_PRINTF("%s: SIOCGIFDEVMTU failed for %s\n",
		    __func__, if_name(ifp));
		/* use default flowswitch buffer size */
		if_max_mtu = NX_FSW_BUFSIZE;
	} else {
		DLIL_PRINTF("%s: %s %d %d\n", __func__, if_name(ifp),
		    ifdm.ifdm_max, ifdm.ifdm_current);
		/* rdar://problem/44589731 */
		if_max_mtu = MAX(ifdm.ifdm_max, ifdm.ifdm_current);
	}

skip_mtu_ioctl:
	if (if_max_mtu == 0) {
		DLIL_PRINTF("%s: can't determine MAX MTU for %s\n",
		    __func__, if_name(ifp));
		return EINVAL;
	}
	if ((if_max_mtu > NX_FSW_MAXBUFSIZE) && fsw_use_max_mtu_buffer) {
		DLIL_PRINTF("%s: interace (%s) has MAX MTU (%u) > flowswitch "
		    "max bufsize(%d)\n", __func__,
		    if_name(ifp), if_max_mtu, NX_FSW_MAXBUFSIZE);
		return EINVAL;
	}

	/*
	 * for skywalk native driver, consult the driver packet pool also.
	 */
	if (dlil_is_native_netif_nexus(ifp)) {
		err = kern_nexus_get_pbufpool_info(netif, &rx_pp_info,
		    &tx_pp_info);
		if (err != 0) {
			DLIL_PRINTF("%s: can't get pbufpool info for %s\n",
			    __func__, if_name(ifp));
			return ENXIO;
		}
		drv_buf_size = tx_pp_info.kpm_bufsize *
		    tx_pp_info.kpm_max_frags;
		if (if_max_mtu > drv_buf_size) {
			DLIL_PRINTF("%s: interface %s packet pool (rx %d * %d, "
			    "tx %d * %d) can't support max mtu(%d)\n", __func__,
			    if_name(ifp), rx_pp_info.kpm_bufsize,
			    rx_pp_info.kpm_max_frags, tx_pp_info.kpm_bufsize,
			    tx_pp_info.kpm_max_frags, if_max_mtu);
			return EINVAL;
		}
	} else {
		drv_buf_size = if_max_mtu;
	}

	if ((drv_buf_size > NX_FSW_BUFSIZE) && (!fsw_use_max_mtu_buffer)) {
		_CASSERT((NX_FSW_BUFSIZE * NX_PBUF_FRAGS_MAX) >= IP_MAXPACKET);
		*use_multi_buflet = true;
		/* default flowswitch buffer size */
		*buf_size = NX_FSW_BUFSIZE;
		*large_buf_size = MIN(NX_FSW_MAX_LARGE_BUFSIZE, drv_buf_size);
	} else {
		*buf_size = MAX(drv_buf_size, NX_FSW_BUFSIZE);
	}
	_dlil_adjust_large_buf_size_for_tso(ifp, large_buf_size);
	ASSERT(*buf_size <= NX_FSW_MAXBUFSIZE);
	if (*buf_size >= *large_buf_size) {
		*large_buf_size = 0;
	}
	return 0;
}

static boolean_t
_dlil_attach_flowswitch_nexus(ifnet_t ifp, if_nexus_flowswitch_t nexus_fsw)
{
	nexus_attr_t            __single attr = NULL;
	nexus_controller_t      controller;
	errno_t                 err = 0;
	uuid_t                  netif;
	uint32_t                buf_size = 0;
	uint32_t                large_buf_size = 0;
	bool                    multi_buflet;

	if (ifnet_nx_noauto(ifp) || ifnet_nx_noauto_flowswitch(ifp) ||
	    IFNET_IS_VMNET(ifp)) {
		goto failed;
	}

	if ((ifp->if_capabilities & IFCAP_SKYWALK) == 0) {
		/* not possible to attach (netif native/compat not plumbed) */
		goto failed;
	}

	if ((if_attach_nx & IF_ATTACH_NX_FLOWSWITCH) == 0) {
		/* don't auto-attach */
		goto failed;
	}

	/* get the netif instance from the ifp */
	err = kern_nexus_get_netif_instance(ifp, netif);
	if (err != 0) {
		DLIL_PRINTF("%s: can't find netif for %s\n", __func__,
		    if_name(ifp));
		goto failed;
	}

	err = kern_nexus_attr_create(&attr);
	if (err != 0) {
		DLIL_PRINTF("%s: nexus attr create for %s\n", __func__,
		    if_name(ifp));
		goto failed;
	}

	err = _dlil_get_flowswitch_buffer_size(ifp, netif, &buf_size,
	    &multi_buflet, &large_buf_size);
	if (err != 0) {
		goto failed;
	}
	ASSERT((buf_size >= NX_FSW_BUFSIZE) && (buf_size <= NX_FSW_MAXBUFSIZE));
	ASSERT(large_buf_size <= NX_FSW_MAX_LARGE_BUFSIZE);

	/* Configure flowswitch buffer size */
	err = kern_nexus_attr_set(attr, NEXUS_ATTR_SLOT_BUF_SIZE, buf_size);
	VERIFY(err == 0);
	err = kern_nexus_attr_set(attr, NEXUS_ATTR_LARGE_BUF_SIZE,
	    large_buf_size);
	VERIFY(err == 0);

	/*
	 * Configure flowswitch to use super-packet (multi-buflet).
	 */
	err = kern_nexus_attr_set(attr, NEXUS_ATTR_MAX_FRAGS,
	    multi_buflet ? NX_PBUF_FRAGS_MAX : 1);
	VERIFY(err == 0);

	/* create the flowswitch provider and instance */
	controller = kern_nexus_shared_controller();
	err = dlil_create_provider_and_instance(controller,
	    NEXUS_TYPE_FLOW_SWITCH, ifp, &nexus_fsw->if_fsw_provider,
	    &nexus_fsw->if_fsw_instance, attr);
	if (err != 0) {
		goto failed;
	}

	/* attach the device port */
	err = kern_nexus_ifattach(controller, nexus_fsw->if_fsw_instance,
	    NULL, netif, FALSE, &nexus_fsw->if_fsw_device);
	if (err != 0) {
		DLIL_PRINTF("%s kern_nexus_ifattach device failed %d %s\n",
		    __func__, err, if_name(ifp));
		/* cleanup provider and instance */
		dlil_detach_nexus(__func__, nexus_fsw->if_fsw_provider,
		    nexus_fsw->if_fsw_instance, nexus_fsw->if_fsw_device);
		goto failed;
	}
	return TRUE;

failed:
	if (err != 0) {
		DLIL_PRINTF("%s: failed to attach flowswitch to %s, error %d\n",
		    __func__, if_name(ifp), err);
	} else {
		DLIL_PRINTF("%s: not attaching flowswitch to %s\n",
		    __func__, if_name(ifp));
	}
	if (attr != NULL) {
		kern_nexus_attr_destroy(attr);
	}
	return FALSE;
}

static boolean_t
dlil_attach_flowswitch_nexus(ifnet_t ifp)
{
	boolean_t               attached = FALSE;
	if_nexus_flowswitch     nexus_fsw;

#if (DEVELOPMENT || DEBUG)
	if (skywalk_netif_direct_allowed(if_name(ifp))) {
		DLIL_PRINTF("skip attaching fsw to %s\n", if_name(ifp));
		return FALSE;
	}
#endif /* (DEVELOPMENT || DEBUG) */

	/*
	 * flowswitch attachment is not supported for interface using the
	 * legacy model (IFNET_INIT_LEGACY)
	 */
	if ((ifp->if_eflags & IFEF_TXSTART) == 0) {
		DLIL_PRINTF("skip attaching fsw to %s using legacy TX model\n",
		    if_name(ifp));
		return FALSE;
	}
	bzero(&nexus_fsw, sizeof(nexus_fsw));
	if (!ifnet_is_attached(ifp, 1)) {
		os_log(OS_LOG_DEFAULT, "%s: %s not attached",
		    __func__, ifp->if_xname);
		goto done;
	}
	if (uuid_is_null(ifp->if_nx_flowswitch.if_fsw_instance)) {
		attached = _dlil_attach_flowswitch_nexus(ifp, &nexus_fsw);
		if (attached) {
			ifnet_lock_exclusive(ifp);
			ifp->if_nx_flowswitch = nexus_fsw;
			ifnet_lock_done(ifp);
		}
	}
	ifnet_decr_iorefcnt(ifp);

done:
	return attached;
}

__attribute__((noinline))
static void
dlil_detach_flowswitch_nexus(if_nexus_flowswitch_t nexus_fsw)
{
	dlil_detach_nexus(__func__, nexus_fsw->if_fsw_provider,
	    nexus_fsw->if_fsw_instance, nexus_fsw->if_fsw_device);
}

__attribute__((noinline))
static void
dlil_netif_detach_notify(ifnet_t ifp)
{
	ifnet_detach_notify_cb_t notify = NULL;
	void *__single arg = NULL;

	ifnet_get_detach_notify(ifp, &notify, &arg);
	if (notify == NULL) {
		DTRACE_SKYWALK1(no__notify, ifnet_t, ifp);
		return;
	}
	(*notify)(arg);
}

__attribute__((noinline))
static void
dlil_quiesce_and_detach_nexuses(ifnet_t ifp)
{
	if_nexus_flowswitch *nx_fsw = &ifp->if_nx_flowswitch;
	if_nexus_netif *nx_netif = &ifp->if_nx_netif;

	ifnet_datamov_suspend_and_drain(ifp);
	if (!uuid_is_null(nx_fsw->if_fsw_device)) {
		ASSERT(!uuid_is_null(nx_fsw->if_fsw_provider));
		ASSERT(!uuid_is_null(nx_fsw->if_fsw_instance));
		dlil_detach_flowswitch_nexus(nx_fsw);
	} else {
		ASSERT(uuid_is_null(nx_fsw->if_fsw_provider));
		ASSERT(uuid_is_null(nx_fsw->if_fsw_instance));
		DTRACE_IP1(fsw__not__attached, ifnet_t, ifp);
	}

	if (!uuid_is_null(nx_netif->if_nif_attach)) {
		ASSERT(!uuid_is_null(nx_netif->if_nif_provider));
		ASSERT(!uuid_is_null(nx_netif->if_nif_instance));
		dlil_detach_netif_nexus(nx_netif);
	} else {
		ASSERT(uuid_is_null(nx_netif->if_nif_provider));
		ASSERT(uuid_is_null(nx_netif->if_nif_instance));
		DTRACE_IP1(netif__not__attached, ifnet_t, ifp);
	}
	ifnet_datamov_resume(ifp);
}

boolean_t
ifnet_add_netagent(ifnet_t ifp)
{
	int     error;

	error = kern_nexus_interface_add_netagent(ifp);
	os_log(OS_LOG_DEFAULT,
	    "kern_nexus_interface_add_netagent(%s) returned %d",
	    ifp->if_xname, error);
	return error == 0;
}

boolean_t
ifnet_remove_netagent(ifnet_t ifp)
{
	int     error;

	error = kern_nexus_interface_remove_netagent(ifp);
	os_log(OS_LOG_DEFAULT,
	    "kern_nexus_interface_remove_netagent(%s) returned %d",
	    ifp->if_xname, error);
	return error == 0;
}

boolean_t
ifnet_attach_flowswitch_nexus(ifnet_t ifp)
{
	if (!IF_FULLY_ATTACHED(ifp)) {
		return FALSE;
	}
	return dlil_attach_flowswitch_nexus(ifp);
}

boolean_t
ifnet_detach_flowswitch_nexus(ifnet_t ifp)
{
	if_nexus_flowswitch     nexus_fsw;

	ifnet_lock_exclusive(ifp);
	nexus_fsw = ifp->if_nx_flowswitch;
	bzero(&ifp->if_nx_flowswitch, sizeof(ifp->if_nx_flowswitch));
	ifnet_lock_done(ifp);
	return dlil_detach_nexus(__func__, nexus_fsw.if_fsw_provider,
	           nexus_fsw.if_fsw_instance, nexus_fsw.if_fsw_device);
}

void
ifnet_attach_native_flowswitch(ifnet_t ifp)
{
	if (!dlil_is_native_netif_nexus(ifp)) {
		/* not a native netif */
		return;
	}
	ifnet_attach_flowswitch_nexus(ifp);
}

int
ifnet_set_flowswitch_rx_callback(ifnet_t ifp, ifnet_fsw_rx_cb_t cb, void *arg)
{
	lck_mtx_lock(&ifp->if_delegate_lock);
	while (ifp->if_fsw_rx_cb_ref > 0) {
		DTRACE_SKYWALK1(wait__fsw, ifnet_t, ifp);
		(void) msleep(&ifp->if_fsw_rx_cb_ref, &ifp->if_delegate_lock,
		    (PZERO + 1), __FUNCTION__, NULL);
		DTRACE_SKYWALK1(wake__fsw, ifnet_t, ifp);
	}
	ifp->if_fsw_rx_cb = cb;
	ifp->if_fsw_rx_cb_arg = arg;
	lck_mtx_unlock(&ifp->if_delegate_lock);
	return 0;
}

int
ifnet_get_flowswitch_rx_callback(ifnet_t ifp, ifnet_fsw_rx_cb_t *cbp, void **argp)
{
	/*
	 * This is for avoiding the unnecessary lock acquire for interfaces
	 * not used by a redirect interface.
	 */
	if (ifp->if_fsw_rx_cb == NULL) {
		return ENOENT;
	}
	lck_mtx_lock(&ifp->if_delegate_lock);
	if (ifp->if_fsw_rx_cb == NULL) {
		lck_mtx_unlock(&ifp->if_delegate_lock);
		return ENOENT;
	}
	*cbp = ifp->if_fsw_rx_cb;
	*argp = ifp->if_fsw_rx_cb_arg;
	ifp->if_fsw_rx_cb_ref++;
	lck_mtx_unlock(&ifp->if_delegate_lock);
	return 0;
}

void
ifnet_release_flowswitch_rx_callback(ifnet_t ifp)
{
	lck_mtx_lock(&ifp->if_delegate_lock);
	if (--ifp->if_fsw_rx_cb_ref == 0) {
		wakeup(&ifp->if_fsw_rx_cb_ref);
	}
	lck_mtx_unlock(&ifp->if_delegate_lock);
}

int
ifnet_set_delegate_parent(ifnet_t difp, ifnet_t parent)
{
	lck_mtx_lock(&difp->if_delegate_lock);
	while (difp->if_delegate_parent_ref > 0) {
		DTRACE_SKYWALK1(wait__parent, ifnet_t, difp);
		(void) msleep(&difp->if_delegate_parent_ref, &difp->if_delegate_lock,
		    (PZERO + 1), __FUNCTION__, NULL);
		DTRACE_SKYWALK1(wake__parent, ifnet_t, difp);
	}
	difp->if_delegate_parent = parent;
	lck_mtx_unlock(&difp->if_delegate_lock);
	return 0;
}

int
ifnet_get_delegate_parent(ifnet_t difp, ifnet_t *parentp)
{
	lck_mtx_lock(&difp->if_delegate_lock);
	if (difp->if_delegate_parent == NULL) {
		lck_mtx_unlock(&difp->if_delegate_lock);
		return ENOENT;
	}
	*parentp = difp->if_delegate_parent;
	difp->if_delegate_parent_ref++;
	lck_mtx_unlock(&difp->if_delegate_lock);
	return 0;
}

void
ifnet_release_delegate_parent(ifnet_t difp)
{
	lck_mtx_lock(&difp->if_delegate_lock);
	if (--difp->if_delegate_parent_ref == 0) {
		wakeup(&difp->if_delegate_parent_ref);
	}
	lck_mtx_unlock(&difp->if_delegate_lock);
}

__attribute__((noinline))
void
ifnet_set_detach_notify_locked(ifnet_t ifp, ifnet_detach_notify_cb_t notify, void *arg)
{
	ifnet_lock_assert(ifp, IFNET_LCK_ASSERT_EXCLUSIVE);
	ifp->if_detach_notify = notify;
	ifp->if_detach_notify_arg = arg;
}

__attribute__((noinline))
void
ifnet_get_detach_notify_locked(ifnet_t ifp, ifnet_detach_notify_cb_t *notifyp, void **argp)
{
	ifnet_lock_assert(ifp, IFNET_LCK_ASSERT_EXCLUSIVE);
	*notifyp = ifp->if_detach_notify;
	*argp = ifp->if_detach_notify_arg;
}

__attribute__((noinline))
void
ifnet_set_detach_notify(ifnet_t ifp, ifnet_detach_notify_cb_t notify, void *arg)
{
	ifnet_lock_exclusive(ifp);
	ifnet_set_detach_notify_locked(ifp, notify, arg);
	ifnet_lock_done(ifp);
}

__attribute__((noinline))
void
ifnet_get_detach_notify(ifnet_t ifp, ifnet_detach_notify_cb_t *notifyp, void **argp)
{
	ifnet_lock_exclusive(ifp);
	ifnet_get_detach_notify_locked(ifp, notifyp, argp);
	ifnet_lock_done(ifp);
}
#endif /* SKYWALK */

#define DLIL_INPUT_CHECK(m, ifp) {                                      \
	ifnet_ref_t _rcvif = mbuf_pkthdr_rcvif(m);                      \
	if (_rcvif == NULL || (ifp != lo_ifp && _rcvif != ifp) ||       \
	    !(mbuf_flags(m) & MBUF_PKTHDR)) {                           \
	        panic_plain("%s: invalid mbuf %p\n", __func__, m);      \
	/* NOTREACHED */                                        \
	}                                                               \
}

#define MBPS    (1ULL * 1000 * 1000)
#define GBPS    (MBPS * 1000)

struct rxpoll_time_tbl {
	u_int64_t       speed;          /* downlink speed */
	u_int32_t       plowat;         /* packets low watermark */
	u_int32_t       phiwat;         /* packets high watermark */
	u_int32_t       blowat;         /* bytes low watermark */
	u_int32_t       bhiwat;         /* bytes high watermark */
};

static struct rxpoll_time_tbl rxpoll_tbl[] = {
	{ .speed =  10 * MBPS, .plowat = 2, .phiwat = 8, .blowat = (1 * 1024), .bhiwat = (6 * 1024)    },
	{ .speed = 100 * MBPS, .plowat = 10, .phiwat = 40, .blowat = (4 * 1024), .bhiwat = (64 * 1024)   },
	{ .speed =   1 * GBPS, .plowat = 10, .phiwat = 40, .blowat = (4 * 1024), .bhiwat = (64 * 1024)   },
	{ .speed =  10 * GBPS, .plowat = 10, .phiwat = 40, .blowat = (4 * 1024), .bhiwat = (64 * 1024)   },
	{ .speed = 100 * GBPS, .plowat = 10, .phiwat = 40, .blowat = (4 * 1024), .bhiwat = (64 * 1024)   },
	{ .speed = 0, .plowat = 0, .phiwat = 0, .blowat = 0, .bhiwat = 0 }
};

int
proto_hash_value(u_int32_t protocol_family)
{
	/*
	 * dlil_proto_unplumb_all() depends on the mapping between
	 * the hash bucket index and the protocol family defined
	 * here; future changes must be applied there as well.
	 */
	switch (protocol_family) {
	case PF_INET:
		return 0;
	case PF_INET6:
		return 1;
	case PF_VLAN:
		return 2;
	case PF_UNSPEC:
	default:
		return 3;
	}
}

__private_extern__ int
dlil_post_msg(struct ifnet *ifp, u_int32_t event_subclass,
    u_int32_t event_code, struct net_event_data *event_data,
    u_int32_t event_data_len, boolean_t suppress_generation)
{
	struct net_event_data ev_data;
	struct kev_msg ev_msg;

	bzero(&ev_msg, sizeof(ev_msg));
	bzero(&ev_data, sizeof(ev_data));
	/*
	 * a net event always starts with a net_event_data structure
	 * but the caller can generate a simple net event or
	 * provide a longer event structure to post
	 */
	ev_msg.vendor_code      = KEV_VENDOR_APPLE;
	ev_msg.kev_class        = KEV_NETWORK_CLASS;
	ev_msg.kev_subclass     = event_subclass;
	ev_msg.event_code       = event_code;

	if (event_data == NULL) {
		event_data = &ev_data;
		event_data_len = sizeof(struct net_event_data);
	}

	strlcpy(&event_data->if_name[0], ifp->if_name, IFNAMSIZ);
	event_data->if_family = ifp->if_family;
	event_data->if_unit   = (u_int32_t)ifp->if_unit;

	ev_msg.dv[0].data_length = event_data_len;
	ev_msg.dv[0].data_ptr    = event_data;
	ev_msg.dv[1].data_length = 0;

	bool update_generation = true;
	if (event_subclass == KEV_DL_SUBCLASS) {
		/* Don't update interface generation for frequent link quality and state changes  */
		switch (event_code) {
		case KEV_DL_LINK_QUALITY_METRIC_CHANGED:
		case KEV_DL_RRC_STATE_CHANGED:
		case KEV_DL_PRIMARY_ELECTED:
			update_generation = false;
			break;
		default:
			break;
		}
	}

	/*
	 * Some events that update generation counts might
	 * want to suppress generation count.
	 * One example is node presence/absence where we still
	 * issue kernel event for the invocation but want to avoid
	 * expensive operation of updating generation which triggers
	 * NECP client updates.
	 */
	if (suppress_generation) {
		update_generation = false;
	}

	return dlil_event_internal(ifp, &ev_msg, update_generation);
}

static void
dlil_reset_rxpoll_params(ifnet_t ifp)
{
	ASSERT(ifp != NULL);
	ifnet_set_poll_cycle(ifp, NULL);
	ifp->if_poll_update = 0;
	ifp->if_poll_flags = 0;
	ifp->if_poll_req = 0;
	ifp->if_poll_mode = IFNET_MODEL_INPUT_POLL_OFF;
	bzero(&ifp->if_poll_tstats, sizeof(ifp->if_poll_tstats));
	bzero(&ifp->if_poll_pstats, sizeof(ifp->if_poll_pstats));
	bzero(&ifp->if_poll_sstats, sizeof(ifp->if_poll_sstats));
	net_timerclear(&ifp->if_poll_mode_holdtime);
	net_timerclear(&ifp->if_poll_mode_lasttime);
	net_timerclear(&ifp->if_poll_sample_holdtime);
	net_timerclear(&ifp->if_poll_sample_lasttime);
	net_timerclear(&ifp->if_poll_dbg_lasttime);
}


#if SKYWALK
static void
dlil_filter_event(struct eventhandler_entry_arg arg __unused,
    enum net_filter_event_subsystems state)
{
	evhlog(debug, "%s: eventhandler saw event type=net_filter_event_state event_code=0x%d",
	    __func__, state);

	bool old_if_enable_fsw_transport_netagent = if_enable_fsw_transport_netagent;
	if ((state & ~NET_FILTER_EVENT_PF_PRIVATE_PROXY) == 0) {
		if_enable_fsw_transport_netagent = 1;
	} else {
		if_enable_fsw_transport_netagent = 0;
	}
	if (old_if_enable_fsw_transport_netagent != if_enable_fsw_transport_netagent) {
		kern_nexus_update_netagents();
	} else if (!if_enable_fsw_transport_netagent) {
		necp_update_all_clients();
	}
}
#endif /* SKYWALK */

void
dlil_init(void)
{
	thread_t __single thread = THREAD_NULL;

	dlil_main_input_thread = (struct dlil_threading_info *) &dlil_main_input_thread_info;

	/*
	 * The following fields must be 64-bit aligned for atomic operations.
	 */
	IF_DATA_REQUIRE_ALIGNED_64(ifi_ipackets);
	IF_DATA_REQUIRE_ALIGNED_64(ifi_ierrors);
	IF_DATA_REQUIRE_ALIGNED_64(ifi_opackets);
	IF_DATA_REQUIRE_ALIGNED_64(ifi_oerrors);
	IF_DATA_REQUIRE_ALIGNED_64(ifi_collisions);
	IF_DATA_REQUIRE_ALIGNED_64(ifi_ibytes);
	IF_DATA_REQUIRE_ALIGNED_64(ifi_obytes);
	IF_DATA_REQUIRE_ALIGNED_64(ifi_imcasts);
	IF_DATA_REQUIRE_ALIGNED_64(ifi_omcasts);
	IF_DATA_REQUIRE_ALIGNED_64(ifi_iqdrops);
	IF_DATA_REQUIRE_ALIGNED_64(ifi_noproto);
	IF_DATA_REQUIRE_ALIGNED_64(ifi_alignerrs);
	IF_DATA_REQUIRE_ALIGNED_64(ifi_dt_bytes);
	IF_DATA_REQUIRE_ALIGNED_64(ifi_fpackets);
	IF_DATA_REQUIRE_ALIGNED_64(ifi_fbytes);

	IFNET_IF_DATA_REQUIRE_ALIGNED_64(ifi_ipackets);
	IFNET_IF_DATA_REQUIRE_ALIGNED_64(ifi_ierrors);
	IFNET_IF_DATA_REQUIRE_ALIGNED_64(ifi_opackets);
	IFNET_IF_DATA_REQUIRE_ALIGNED_64(ifi_oerrors);
	IFNET_IF_DATA_REQUIRE_ALIGNED_64(ifi_collisions);
	IFNET_IF_DATA_REQUIRE_ALIGNED_64(ifi_ibytes);
	IFNET_IF_DATA_REQUIRE_ALIGNED_64(ifi_obytes);
	IFNET_IF_DATA_REQUIRE_ALIGNED_64(ifi_imcasts);
	IFNET_IF_DATA_REQUIRE_ALIGNED_64(ifi_omcasts);
	IFNET_IF_DATA_REQUIRE_ALIGNED_64(ifi_iqdrops);
	IFNET_IF_DATA_REQUIRE_ALIGNED_64(ifi_noproto);
	IFNET_IF_DATA_REQUIRE_ALIGNED_64(ifi_alignerrs);
	IFNET_IF_DATA_REQUIRE_ALIGNED_64(ifi_dt_bytes);
	IFNET_IF_DATA_REQUIRE_ALIGNED_64(ifi_fpackets);
	IFNET_IF_DATA_REQUIRE_ALIGNED_64(ifi_fbytes);

	/*
	 * These IF_HWASSIST_ flags must be equal to their IFNET_* counterparts.
	 */
	_CASSERT(IF_HWASSIST_CSUM_IP == IFNET_CSUM_IP);
	_CASSERT(IF_HWASSIST_CSUM_TCP == IFNET_CSUM_TCP);
	_CASSERT(IF_HWASSIST_CSUM_UDP == IFNET_CSUM_UDP);
	_CASSERT(IF_HWASSIST_CSUM_IP_FRAGS == IFNET_CSUM_FRAGMENT);
	_CASSERT(IF_HWASSIST_CSUM_FRAGMENT == IFNET_IP_FRAGMENT);
	_CASSERT(IF_HWASSIST_CSUM_TCPIPV6 == IFNET_CSUM_TCPIPV6);
	_CASSERT(IF_HWASSIST_CSUM_UDPIPV6 == IFNET_CSUM_UDPIPV6);
	_CASSERT(IF_HWASSIST_CSUM_FRAGMENT_IPV6 == IFNET_IPV6_FRAGMENT);
	_CASSERT(IF_HWASSIST_CSUM_PARTIAL == IFNET_CSUM_PARTIAL);
	_CASSERT(IF_HWASSIST_CSUM_ZERO_INVERT == IFNET_CSUM_ZERO_INVERT);
	_CASSERT(IF_HWASSIST_VLAN_TAGGING == IFNET_VLAN_TAGGING);
	_CASSERT(IF_HWASSIST_VLAN_MTU == IFNET_VLAN_MTU);
	_CASSERT(IF_HWASSIST_TSO_V4 == IFNET_TSO_IPV4);
	_CASSERT(IF_HWASSIST_TSO_V6 == IFNET_TSO_IPV6);

	/*
	 * ... as well as the mbuf checksum flags counterparts.
	 */
	_CASSERT(CSUM_IP == IF_HWASSIST_CSUM_IP);
	_CASSERT(CSUM_TCP == IF_HWASSIST_CSUM_TCP);
	_CASSERT(CSUM_UDP == IF_HWASSIST_CSUM_UDP);
	_CASSERT(CSUM_IP_FRAGS == IF_HWASSIST_CSUM_IP_FRAGS);
	_CASSERT(CSUM_FRAGMENT == IF_HWASSIST_CSUM_FRAGMENT);
	_CASSERT(CSUM_TCPIPV6 == IF_HWASSIST_CSUM_TCPIPV6);
	_CASSERT(CSUM_UDPIPV6 == IF_HWASSIST_CSUM_UDPIPV6);
	_CASSERT(CSUM_FRAGMENT_IPV6 == IF_HWASSIST_CSUM_FRAGMENT_IPV6);
	_CASSERT(CSUM_PARTIAL == IF_HWASSIST_CSUM_PARTIAL);
	_CASSERT(CSUM_ZERO_INVERT == IF_HWASSIST_CSUM_ZERO_INVERT);
	_CASSERT(CSUM_VLAN_TAG_VALID == IF_HWASSIST_VLAN_TAGGING);

	/*
	 * Make sure we have at least IF_LLREACH_MAXLEN in the llreach info.
	 */
	_CASSERT(IF_LLREACH_MAXLEN <= IF_LLREACHINFO_ADDRLEN);
	_CASSERT(IFNET_LLREACHINFO_ADDRLEN == IF_LLREACHINFO_ADDRLEN);

	_CASSERT(IFRLOGF_DLIL == IFNET_LOGF_DLIL);
	_CASSERT(IFRLOGF_FAMILY == IFNET_LOGF_FAMILY);
	_CASSERT(IFRLOGF_DRIVER == IFNET_LOGF_DRIVER);
	_CASSERT(IFRLOGF_FIRMWARE == IFNET_LOGF_FIRMWARE);

	_CASSERT(IFRLOGCAT_CONNECTIVITY == IFNET_LOGCAT_CONNECTIVITY);
	_CASSERT(IFRLOGCAT_QUALITY == IFNET_LOGCAT_QUALITY);
	_CASSERT(IFRLOGCAT_PERFORMANCE == IFNET_LOGCAT_PERFORMANCE);

	_CASSERT(IFRTYPE_FAMILY_ANY == IFNET_FAMILY_ANY);
	_CASSERT(IFRTYPE_FAMILY_LOOPBACK == IFNET_FAMILY_LOOPBACK);
	_CASSERT(IFRTYPE_FAMILY_ETHERNET == IFNET_FAMILY_ETHERNET);
	_CASSERT(IFRTYPE_FAMILY_SLIP == IFNET_FAMILY_SLIP);
	_CASSERT(IFRTYPE_FAMILY_TUN == IFNET_FAMILY_TUN);
	_CASSERT(IFRTYPE_FAMILY_VLAN == IFNET_FAMILY_VLAN);
	_CASSERT(IFRTYPE_FAMILY_PPP == IFNET_FAMILY_PPP);
	_CASSERT(IFRTYPE_FAMILY_PVC == IFNET_FAMILY_PVC);
	_CASSERT(IFRTYPE_FAMILY_DISC == IFNET_FAMILY_DISC);
	_CASSERT(IFRTYPE_FAMILY_MDECAP == IFNET_FAMILY_MDECAP);
	_CASSERT(IFRTYPE_FAMILY_GIF == IFNET_FAMILY_GIF);
	_CASSERT(IFRTYPE_FAMILY_FAITH == IFNET_FAMILY_FAITH);
	_CASSERT(IFRTYPE_FAMILY_STF == IFNET_FAMILY_STF);
	_CASSERT(IFRTYPE_FAMILY_FIREWIRE == IFNET_FAMILY_FIREWIRE);
	_CASSERT(IFRTYPE_FAMILY_BOND == IFNET_FAMILY_BOND);
	_CASSERT(IFRTYPE_FAMILY_CELLULAR == IFNET_FAMILY_CELLULAR);
	_CASSERT(IFRTYPE_FAMILY_UTUN == IFNET_FAMILY_UTUN);
	_CASSERT(IFRTYPE_FAMILY_IPSEC == IFNET_FAMILY_IPSEC);

	_CASSERT(IFRTYPE_SUBFAMILY_ANY == IFNET_SUBFAMILY_ANY);
	_CASSERT(IFRTYPE_SUBFAMILY_USB == IFNET_SUBFAMILY_USB);
	_CASSERT(IFRTYPE_SUBFAMILY_BLUETOOTH == IFNET_SUBFAMILY_BLUETOOTH);
	_CASSERT(IFRTYPE_SUBFAMILY_WIFI == IFNET_SUBFAMILY_WIFI);
	_CASSERT(IFRTYPE_SUBFAMILY_THUNDERBOLT == IFNET_SUBFAMILY_THUNDERBOLT);
	_CASSERT(IFRTYPE_SUBFAMILY_RESERVED == IFNET_SUBFAMILY_RESERVED);
	_CASSERT(IFRTYPE_SUBFAMILY_INTCOPROC == IFNET_SUBFAMILY_INTCOPROC);
	_CASSERT(IFRTYPE_SUBFAMILY_QUICKRELAY == IFNET_SUBFAMILY_QUICKRELAY);
	_CASSERT(IFRTYPE_SUBFAMILY_VMNET == IFNET_SUBFAMILY_VMNET);
	_CASSERT(IFRTYPE_SUBFAMILY_SIMCELL == IFNET_SUBFAMILY_SIMCELL);
	_CASSERT(IFRTYPE_SUBFAMILY_MANAGEMENT == IFNET_SUBFAMILY_MANAGEMENT);

	_CASSERT(DLIL_MODIDLEN == IFNET_MODIDLEN);
	_CASSERT(DLIL_MODARGLEN == IFNET_MODARGLEN);

	PE_parse_boot_argn("net_affinity", &net_affinity,
	    sizeof(net_affinity));

	PE_parse_boot_argn("net_rxpoll", &net_rxpoll, sizeof(net_rxpoll));

	PE_parse_boot_argn("net_rtref", &net_rtref, sizeof(net_rtref));

	PE_parse_boot_argn("net_async", &net_async, sizeof(net_async));

	PE_parse_boot_argn("ifnet_debug", &ifnet_debug, sizeof(ifnet_debug));

	PE_parse_boot_argn("if_link_heuristics", &if_link_heuristics_flags, sizeof(if_link_heuristics_flags));

	VERIFY(dlil_pending_thread_cnt == 0);
#if SKYWALK
	boolean_t pe_enable_fsw_transport_netagent = FALSE;
	boolean_t pe_disable_fsw_transport_netagent = FALSE;
	boolean_t enable_fsw_netagent =
	    (((if_attach_nx & IF_ATTACH_NX_FSW_TRANSPORT_NETAGENT) != 0) ||
	    (if_attach_nx & IF_ATTACH_NX_FSW_IP_NETAGENT) != 0);

	/*
	 * Check the device tree to see if Skywalk netagent has been explicitly
	 * enabled or disabled.  This can be overridden via if_attach_nx below.
	 * Note that the property is a 0-length key, and so checking for the
	 * presence itself is enough (no need to check for the actual value of
	 * the retrieved variable.)
	 */
	pe_enable_fsw_transport_netagent =
	    PE_get_default("kern.skywalk_netagent_enable",
	    &pe_enable_fsw_transport_netagent,
	    sizeof(pe_enable_fsw_transport_netagent));
	pe_disable_fsw_transport_netagent =
	    PE_get_default("kern.skywalk_netagent_disable",
	    &pe_disable_fsw_transport_netagent,
	    sizeof(pe_disable_fsw_transport_netagent));

	/*
	 * These two are mutually exclusive, i.e. they both can be absent,
	 * but only one can be present at a time, and so we assert to make
	 * sure it is correct.
	 */
	VERIFY((!pe_enable_fsw_transport_netagent &&
	    !pe_disable_fsw_transport_netagent) ||
	    (pe_enable_fsw_transport_netagent ^
	    pe_disable_fsw_transport_netagent));

	if (pe_enable_fsw_transport_netagent) {
		kprintf("SK: netagent is enabled via an override for "
		    "this platform\n");
		if_attach_nx = SKYWALK_NETWORKING_ENABLED;
	} else if (pe_disable_fsw_transport_netagent) {
		kprintf("SK: netagent is disabled via an override for "
		    "this platform\n");
		if_attach_nx = SKYWALK_NETWORKING_DISABLED;
	} else {
		kprintf("SK: netagent is %s by default for this platform\n",
		    (enable_fsw_netagent ? "enabled" : "disabled"));
		if_attach_nx = IF_ATTACH_NX_DEFAULT;
	}

	/*
	 * Now see if there's a boot-arg override.
	 */
	(void) PE_parse_boot_argn("if_attach_nx", &if_attach_nx,
	    sizeof(if_attach_nx));
	if_enable_fsw_transport_netagent =
	    ((if_attach_nx & IF_ATTACH_NX_FSW_TRANSPORT_NETAGENT) != 0);

	if_netif_all = ((if_attach_nx & IF_ATTACH_NX_NETIF_ALL) != 0);

	if (pe_disable_fsw_transport_netagent &&
	    if_enable_fsw_transport_netagent) {
		kprintf("SK: netagent is force-enabled\n");
	} else if (!pe_disable_fsw_transport_netagent &&
	    !if_enable_fsw_transport_netagent) {
		kprintf("SK: netagent is force-disabled\n");
	}
	if (kernel_is_macos_or_server() && if_enable_fsw_transport_netagent) {
		net_filter_event_register(dlil_filter_event);
	}

#if (DEVELOPMENT || DEBUG)
	(void) PE_parse_boot_argn("fsw_use_max_mtu_buffer",
	    &fsw_use_max_mtu_buffer, sizeof(fsw_use_max_mtu_buffer));
#endif /* (DEVELOPMENT || DEBUG) */

#endif /* SKYWALK */

	dlil_allocation_zones_init();
	eventhandler_lists_ctxt_init(&ifnet_evhdlr_ctxt);

	TAILQ_INIT(&dlil_ifnet_head);
	TAILQ_INIT(&ifnet_head);
	TAILQ_INIT(&ifnet_detaching_head);
	TAILQ_INIT(&ifnet_ordered_head);

	/* Initialize interface address subsystem */
	ifa_init();

#if PF
	/* Initialize the packet filter */
	pfinit();
#endif /* PF */

	/* Initialize queue algorithms */
	classq_init();

	/* Initialize packet schedulers */
	pktsched_init();

	/* Initialize flow advisory subsystem */
	flowadv_init();

	/* Initialize the pktap virtual interface */
	pktap_init();

	/* Initialize droptap interface */
	droptap_init();

	/* Initialize the service class to dscp map */
	net_qos_map_init();

	/* Initialize the interface low power mode event handler */
	if_low_power_evhdlr_init();

	/* Initialize the interface offload port list subsystem */
	if_ports_used_init();

#if DEBUG || DEVELOPMENT
	/* Run self-tests */
	dlil_verify_sum16();
#endif /* DEBUG || DEVELOPMENT */

	/*
	 * Create and start up the main DLIL input thread and the interface
	 * detacher threads once everything is initialized.
	 */
	dlil_incr_pending_thread_count();
	(void) dlil_create_input_thread(NULL, dlil_main_input_thread, NULL);

	/*
	 * Create ifnet detacher thread.
	 * When an interface gets detached, part of the detach processing
	 * is delayed. The interface is added to delayed detach list
	 * and this thread is woken up to call ifnet_detach_final
	 * on these interfaces.
	 */
	dlil_incr_pending_thread_count();
	if (kernel_thread_start(ifnet_detacher_thread_func,
	    NULL, &thread) != KERN_SUCCESS) {
		panic_plain("%s: couldn't create detacher thread", __func__);
		/* NOTREACHED */
	}
	thread_deallocate(thread);

	/*
	 * Wait for the created kernel threads for dlil to get
	 * scheduled and run at least once before we proceed
	 */
	lck_mtx_lock(&dlil_thread_sync_lock);
	while (dlil_pending_thread_cnt != 0) {
		DLIL_PRINTF("%s: Waiting for all the create dlil kernel "
		    "threads to get scheduled at least once.\n", __func__);
		(void) msleep(&dlil_pending_thread_cnt, &dlil_thread_sync_lock,
		    (PZERO - 1), __func__, NULL);
		LCK_MTX_ASSERT(&dlil_thread_sync_lock, LCK_ASSERT_OWNED);
	}
	lck_mtx_unlock(&dlil_thread_sync_lock);
	DLIL_PRINTF("%s: All the created dlil kernel threads have been "
	    "scheduled at least once. Proceeding.\n", __func__);
}

__private_extern__ int
dlil_attach_filter(struct ifnet *ifp, const struct iff_filter *if_filter,
    interface_filter_t *filter_ref, u_int32_t flags)
{
	int retval = 0;
	struct ifnet_filter *filter = NULL;

	ifnet_head_lock_shared();

	/* Check that the interface is in the global list */
	if (!ifnet_lookup(ifp)) {
		retval = ENXIO;
		goto done;
	}
	if (!ifnet_is_attached(ifp, 1)) {
		os_log(OS_LOG_DEFAULT, "%s: %s is no longer attached",
		    __func__, if_name(ifp));
		retval = ENXIO;
		goto done;
	}

	filter = dlif_filt_alloc();
	/* refcnt held above during lookup */
	filter->filt_flags = flags;
	filter->filt_ifp = ifp;
	filter->filt_cookie = if_filter->iff_cookie;
	filter->filt_name = if_filter->iff_name;
	filter->filt_protocol = if_filter->iff_protocol;
	/*
	 * Do not install filter callbacks for internal coproc interface
	 * and for management interfaces
	 */
	if (!IFNET_IS_INTCOPROC(ifp) && !IFNET_IS_MANAGEMENT(ifp)) {
		filter->filt_input = if_filter->iff_input;
		filter->filt_output = if_filter->iff_output;
		filter->filt_event = if_filter->iff_event;
		filter->filt_ioctl = if_filter->iff_ioctl;
	}
	filter->filt_detached = if_filter->iff_detached;

	lck_mtx_lock(&ifp->if_flt_lock);
	if_flt_monitor_enter(ifp);

	LCK_MTX_ASSERT(&ifp->if_flt_lock, LCK_MTX_ASSERT_OWNED);
	TAILQ_INSERT_TAIL(&ifp->if_flt_head, filter, filt_next);

	*filter_ref = filter;

	/*
	 * Bump filter count and route_generation ID to let TCP
	 * know it shouldn't do TSO on this connection
	 */
	if ((filter->filt_flags & DLIL_IFF_TSO) == 0) {
		ifnet_filter_update_tso(ifp, TRUE);
	}
	OSIncrementAtomic64(&net_api_stats.nas_iflt_attach_count);
	INC_ATOMIC_INT64_LIM(net_api_stats.nas_iflt_attach_total);
	if (filter->filt_flags & DLIL_IFF_INTERNAL) {
		OSIncrementAtomic64(&net_api_stats.nas_iflt_attach_os_count);
		INC_ATOMIC_INT64_LIM(net_api_stats.nas_iflt_attach_os_total);
	} else {
		OSAddAtomic(1, &ifp->if_flt_non_os_count);
	}
	if_flt_monitor_leave(ifp);
	lck_mtx_unlock(&ifp->if_flt_lock);

#if SKYWALK
	if (kernel_is_macos_or_server()) {
		net_filter_event_mark(NET_FILTER_EVENT_INTERFACE,
		    net_check_compatible_if_filter(NULL));
	}
#endif /* SKYWALK */

	if (dlil_verbose) {
		DLIL_PRINTF("%s: %s filter attached\n", if_name(ifp),
		    if_filter->iff_name);
	}
	ifnet_decr_iorefcnt(ifp);

done:
	ifnet_head_done();
	if (retval != 0 && ifp != NULL) {
		DLIL_PRINTF("%s: failed to attach %s (err=%d)\n",
		    if_name(ifp), if_filter->iff_name, retval);
	}
	if (retval != 0 && filter != NULL) {
		dlif_filt_free(filter);
	}

	return retval;
}

static int
dlil_detach_filter_internal(interface_filter_t  filter, int detached)
{
	int retval = 0;

	if (detached == 0) {
		ifnet_ref_t ifp = NULL;

		ifnet_head_lock_shared();
		TAILQ_FOREACH(ifp, &ifnet_head, if_link) {
			interface_filter_t entry = NULL;

			lck_mtx_lock(&ifp->if_flt_lock);
			TAILQ_FOREACH(entry, &ifp->if_flt_head, filt_next) {
				if (entry != filter || entry->filt_skip) {
					continue;
				}
				/*
				 * We've found a match; since it's possible
				 * that the thread gets blocked in the monitor,
				 * we do the lock dance.  Interface should
				 * not be detached since we still have a use
				 * count held during filter attach.
				 */
				entry->filt_skip = 1;   /* skip input/output */
				lck_mtx_unlock(&ifp->if_flt_lock);
				ifnet_head_done();

				lck_mtx_lock(&ifp->if_flt_lock);
				if_flt_monitor_enter(ifp);
				LCK_MTX_ASSERT(&ifp->if_flt_lock,
				    LCK_MTX_ASSERT_OWNED);

				/* Remove the filter from the list */
				TAILQ_REMOVE(&ifp->if_flt_head, filter,
				    filt_next);

				if (dlil_verbose) {
					DLIL_PRINTF("%s: %s filter detached\n",
					    if_name(ifp), filter->filt_name);
				}
				if (!(filter->filt_flags & DLIL_IFF_INTERNAL)) {
					VERIFY(ifp->if_flt_non_os_count != 0);
					OSAddAtomic(-1, &ifp->if_flt_non_os_count);
				}
				/*
				 * Decrease filter count and route_generation
				 * ID to let TCP know it should reevalute doing
				 * TSO or not.
				 */
				if ((filter->filt_flags & DLIL_IFF_TSO) == 0) {
					ifnet_filter_update_tso(ifp, FALSE);
				}
				/*
				 * When we remove the bridge's interface filter,
				 * clear the field in the ifnet.
				 */
				if ((filter->filt_flags & DLIL_IFF_BRIDGE)
				    != 0) {
					ifp->if_bridge = NULL;
				}
				if_flt_monitor_leave(ifp);
				lck_mtx_unlock(&ifp->if_flt_lock);
				goto destroy;
			}
			lck_mtx_unlock(&ifp->if_flt_lock);
		}
		ifnet_head_done();

		/* filter parameter is not a valid filter ref */
		retval = EINVAL;
		goto done;
	} else {
		ifnet_ref_t ifp = filter->filt_ifp;
		/*
		 * Here we are called from ifnet_detach_final(); the
		 * caller had emptied if_flt_head and we're doing an
		 * implicit filter detach because the interface is
		 * about to go away.  Make sure to adjust the counters
		 * in this case.  We don't need the protection of the
		 * filter monitor since we're called as part of the
		 * final detach in the context of the detacher thread.
		 */
		if (!(filter->filt_flags & DLIL_IFF_INTERNAL)) {
			VERIFY(ifp->if_flt_non_os_count != 0);
			OSAddAtomic(-1, &ifp->if_flt_non_os_count);
		}
		/*
		 * Decrease filter count and route_generation
		 * ID to let TCP know it should reevalute doing
		 * TSO or not.
		 */
		if ((filter->filt_flags & DLIL_IFF_TSO) == 0) {
			ifnet_filter_update_tso(ifp, FALSE);
		}
	}

	if (dlil_verbose) {
		DLIL_PRINTF("%s filter detached\n", filter->filt_name);
	}

destroy:

	/* Call the detached function if there is one */
	if (filter->filt_detached) {
		filter->filt_detached(filter->filt_cookie, filter->filt_ifp);
	}

	VERIFY(OSDecrementAtomic64(&net_api_stats.nas_iflt_attach_count) > 0);
	if (filter->filt_flags & DLIL_IFF_INTERNAL) {
		VERIFY(OSDecrementAtomic64(&net_api_stats.nas_iflt_attach_os_count) > 0);
	}
#if SKYWALK
	if (kernel_is_macos_or_server()) {
		net_filter_event_mark(NET_FILTER_EVENT_INTERFACE,
		    net_check_compatible_if_filter(NULL));
	}
#endif /* SKYWALK */

	/* Free the filter */
	dlif_filt_free(filter);
	filter = NULL;
done:
	if (retval != 0 && filter != NULL) {
		DLIL_PRINTF("failed to detach %s filter (err=%d)\n",
		    filter->filt_name, retval);
	}

	return retval;
}

__private_extern__ void
dlil_detach_filter(interface_filter_t filter)
{
	if (filter == NULL) {
		return;
	}
	dlil_detach_filter_internal(filter, 0);
}

__private_extern__ boolean_t
dlil_has_ip_filter(void)
{
	boolean_t has_filter = ((net_api_stats.nas_ipf_add_count - net_api_stats.nas_ipf_add_os_count) > 0);

	VERIFY(net_api_stats.nas_ipf_add_count >= net_api_stats.nas_ipf_add_os_count);

	DTRACE_IP1(dlil_has_ip_filter, boolean_t, has_filter);
	return has_filter;
}

__private_extern__ boolean_t
dlil_has_if_filter(struct ifnet *ifp)
{
	boolean_t has_filter = !TAILQ_EMPTY(&ifp->if_flt_head);
	DTRACE_IP1(dlil_has_if_filter, boolean_t, has_filter);
	return has_filter;
}

errno_t
dlil_rxpoll_validate_params(struct ifnet_poll_params *p)
{
	if (p != NULL) {
		if ((p->packets_lowat == 0 && p->packets_hiwat != 0) ||
		    (p->packets_lowat != 0 && p->packets_hiwat == 0)) {
			return EINVAL;
		}
		if (p->packets_lowat != 0 &&    /* hiwat must be non-zero */
		    p->packets_lowat >= p->packets_hiwat) {
			return EINVAL;
		}
		if ((p->bytes_lowat == 0 && p->bytes_hiwat != 0) ||
		    (p->bytes_lowat != 0 && p->bytes_hiwat == 0)) {
			return EINVAL;
		}
		if (p->bytes_lowat != 0 &&      /* hiwat must be non-zero */
		    p->bytes_lowat >= p->bytes_hiwat) {
			return EINVAL;
		}
		if (p->interval_time != 0 &&
		    p->interval_time < IF_RXPOLL_INTERVALTIME_MIN) {
			p->interval_time = IF_RXPOLL_INTERVALTIME_MIN;
		}
	}
	return 0;
}

void
dlil_rxpoll_update_params(struct ifnet *ifp, struct ifnet_poll_params *p)
{
	u_int64_t sample_holdtime, inbw;

	if ((inbw = ifnet_input_linkrate(ifp)) == 0 && p == NULL) {
		sample_holdtime = 0;    /* polling is disabled */
		ifp->if_rxpoll_wlowat = ifp->if_rxpoll_plowat =
		    ifp->if_rxpoll_blowat = 0;
		ifp->if_rxpoll_whiwat = ifp->if_rxpoll_phiwat =
		    ifp->if_rxpoll_bhiwat = (u_int32_t)-1;
		ifp->if_rxpoll_plim = 0;
		ifp->if_rxpoll_ival = IF_RXPOLL_INTERVALTIME_MIN;
	} else {
		u_int32_t plowat, phiwat, blowat, bhiwat, plim;
		u_int64_t ival;
		unsigned int n, i;

		for (n = 0, i = 0; rxpoll_tbl[i].speed != 0; i++) {
			if (inbw < rxpoll_tbl[i].speed) {
				break;
			}
			n = i;
		}
		/* auto-tune if caller didn't specify a value */
		plowat = ((p == NULL || p->packets_lowat == 0) ?
		    rxpoll_tbl[n].plowat : p->packets_lowat);
		phiwat = ((p == NULL || p->packets_hiwat == 0) ?
		    rxpoll_tbl[n].phiwat : p->packets_hiwat);
		blowat = ((p == NULL || p->bytes_lowat == 0) ?
		    rxpoll_tbl[n].blowat : p->bytes_lowat);
		bhiwat = ((p == NULL || p->bytes_hiwat == 0) ?
		    rxpoll_tbl[n].bhiwat : p->bytes_hiwat);
		plim = ((p == NULL || p->packets_limit == 0 ||
		    if_rxpoll_max != 0) ?  if_rxpoll_max : p->packets_limit);
		ival = ((p == NULL || p->interval_time == 0 ||
		    if_rxpoll_interval_time != IF_RXPOLL_INTERVALTIME) ?
		    if_rxpoll_interval_time : p->interval_time);

		VERIFY(plowat != 0 && phiwat != 0);
		VERIFY(blowat != 0 && bhiwat != 0);
		VERIFY(ival >= IF_RXPOLL_INTERVALTIME_MIN);

		sample_holdtime = if_rxpoll_sample_holdtime;
		ifp->if_rxpoll_wlowat = if_sysctl_rxpoll_wlowat;
		ifp->if_rxpoll_whiwat = if_sysctl_rxpoll_whiwat;
		ifp->if_rxpoll_plowat = plowat;
		ifp->if_rxpoll_phiwat = phiwat;
		ifp->if_rxpoll_blowat = blowat;
		ifp->if_rxpoll_bhiwat = bhiwat;
		ifp->if_rxpoll_plim = plim;
		ifp->if_rxpoll_ival = ival;
	}

	net_nsectimer(&if_rxpoll_mode_holdtime, &ifp->if_poll_mode_holdtime);
	net_nsectimer(&sample_holdtime, &ifp->if_poll_sample_holdtime);

	if (dlil_verbose) {
		DLIL_PRINTF("%s: speed %llu bps, sample per %llu nsec, "
		    "poll interval %llu nsec, pkts per poll %u, "
		    "pkt limits [%u/%u], wreq limits [%u/%u], "
		    "bytes limits [%u/%u]\n", if_name(ifp),
		    inbw, sample_holdtime, ifp->if_rxpoll_ival,
		    ifp->if_rxpoll_plim, ifp->if_rxpoll_plowat,
		    ifp->if_rxpoll_phiwat, ifp->if_rxpoll_wlowat,
		    ifp->if_rxpoll_whiwat, ifp->if_rxpoll_blowat,
		    ifp->if_rxpoll_bhiwat);
	}
}

/*
 * Must be called on an attached ifnet (caller is expected to check.)
 * Caller may pass NULL for poll parameters to indicate "auto-tuning."
 */
errno_t
dlil_rxpoll_set_params(struct ifnet *ifp, struct ifnet_poll_params *p,
    boolean_t locked)
{
	errno_t err;
	struct dlil_threading_info *inp;

	VERIFY(ifp != NULL);
	if (!(ifp->if_eflags & IFEF_RXPOLL) || (inp = ifp->if_inp) == NULL) {
		return ENXIO;
	}
	err = dlil_rxpoll_validate_params(p);
	if (err != 0) {
		return err;
	}

	if (!locked) {
		lck_mtx_lock(&inp->dlth_lock);
	}
	LCK_MTX_ASSERT(&inp->dlth_lock, LCK_MTX_ASSERT_OWNED);
	/*
	 * Normally, we'd reset the parameters to the auto-tuned values
	 * if the the input thread detects a change in link rate.  If the
	 * driver provides its own parameters right after a link rate
	 * changes, but before the input thread gets to run, we want to
	 * make sure to keep the driver's values.  Clearing if_poll_update
	 * will achieve that.
	 */
	if (p != NULL && !locked && ifp->if_poll_update != 0) {
		ifp->if_poll_update = 0;
	}
	dlil_rxpoll_update_params(ifp, p);
	if (!locked) {
		lck_mtx_unlock(&inp->dlth_lock);
	}
	return 0;
}

/*
 * Must be called on an attached ifnet (caller is expected to check.)
 */
errno_t
dlil_rxpoll_get_params(struct ifnet *ifp, struct ifnet_poll_params *p)
{
	struct dlil_threading_info *inp;

	VERIFY(ifp != NULL && p != NULL);
	if (!(ifp->if_eflags & IFEF_RXPOLL) || (inp = ifp->if_inp) == NULL) {
		return ENXIO;
	}

	bzero(p, sizeof(*p));

	lck_mtx_lock(&inp->dlth_lock);
	p->packets_limit = ifp->if_rxpoll_plim;
	p->packets_lowat = ifp->if_rxpoll_plowat;
	p->packets_hiwat = ifp->if_rxpoll_phiwat;
	p->bytes_lowat = ifp->if_rxpoll_blowat;
	p->bytes_hiwat = ifp->if_rxpoll_bhiwat;
	p->interval_time = ifp->if_rxpoll_ival;
	lck_mtx_unlock(&inp->dlth_lock);

	return 0;
}

errno_t
ifnet_input(struct ifnet *ifp, struct mbuf *m_head,
    const struct ifnet_stat_increment_param *s)
{
	return ifnet_input_common(ifp, m_head, NULL, s, FALSE, FALSE);
}

errno_t
ifnet_input_extended(struct ifnet *ifp, struct mbuf *m_head,
    struct mbuf *m_tail, const struct ifnet_stat_increment_param *s)
{
	return ifnet_input_common(ifp, m_head, m_tail, s, TRUE, FALSE);
}

errno_t
ifnet_input_poll(struct ifnet *ifp, struct mbuf *m_head,
    struct mbuf *m_tail, const struct ifnet_stat_increment_param *s)
{
	return ifnet_input_common(ifp, m_head, m_tail, s,
	           (m_head != NULL), TRUE);
}

static errno_t
ifnet_input_common(struct ifnet *ifp, struct mbuf *m_head, struct mbuf *m_tail,
    const struct ifnet_stat_increment_param *s, boolean_t ext, boolean_t poll)
{
	dlil_input_func input_func;
	struct ifnet_stat_increment_param _s;
	u_int32_t m_cnt = 0, m_size = 0;
	struct mbuf *last;
	errno_t err = 0;

	if ((m_head == NULL && !poll) || (s == NULL && ext)) {
		if (m_head != NULL) {
			mbuf_freem_list(m_head);
		}
		return EINVAL;
	}

	VERIFY(m_head != NULL || (s == NULL && m_tail == NULL && !ext && poll));
	VERIFY(m_tail == NULL || ext);
	VERIFY(s != NULL || !ext);

	/*
	 * Drop the packet(s) if the parameters are invalid, or if the
	 * interface is no longer attached; else hold an IO refcnt to
	 * prevent it from being detached (will be released below.)
	 */
	if (ifp == NULL || (ifp != lo_ifp && !ifnet_datamov_begin(ifp))) {
		if (m_head != NULL) {
			mbuf_freem_list(m_head);
		}
		return EINVAL;
	}

	input_func = ifp->if_input_dlil;
	VERIFY(input_func != NULL);

	if (m_tail == NULL) {
		last = m_head;
		while (m_head != NULL) {
			m_add_hdr_crumb_interface_input(last, ifp->if_index, false);
#if IFNET_INPUT_SANITY_CHK
			if (__improbable(dlil_input_sanity_check != 0)) {
				DLIL_INPUT_CHECK(last, ifp);
			}
#endif /* IFNET_INPUT_SANITY_CHK */
			m_cnt++;
			m_size += m_length(last);
			if (mbuf_nextpkt(last) == NULL) {
				break;
			}
			last = mbuf_nextpkt(last);
		}
		m_tail = last;
	} else {
#if IFNET_INPUT_SANITY_CHK
		if (__improbable(dlil_input_sanity_check != 0)) {
			last = m_head;
			while (1) {
				m_add_hdr_crumb_interface_input(last, ifp->if_index, false);
				DLIL_INPUT_CHECK(last, ifp);
				m_cnt++;
				m_size += m_length(last);
				if (mbuf_nextpkt(last) == NULL) {
					break;
				}
				last = mbuf_nextpkt(last);
			}
		} else {
			m_add_hdr_crumb_interface_input(m_head, ifp->if_index, true);
			m_cnt = s->packets_in;
			m_size = s->bytes_in;
			last = m_tail;
		}
#else
		m_add_hdr_crumb_interface_input(m_head, ifp->if_index, true);
		m_cnt = s->packets_in;
		m_size = s->bytes_in;
		last = m_tail;
#endif /* IFNET_INPUT_SANITY_CHK */
	}

	if (last != m_tail) {
		panic_plain("%s: invalid input packet chain for %s, "
		    "tail mbuf %p instead of %p\n", __func__, if_name(ifp),
		    m_tail, last);
	}

	/*
	 * Assert packet count only for the extended variant, for backwards
	 * compatibility, since this came directly from the device driver.
	 * Relax this assertion for input bytes, as the driver may have
	 * included the link-layer headers in the computation; hence
	 * m_size is just an approximation.
	 */
	if (ext && s->packets_in != m_cnt) {
		panic_plain("%s: input packet count mismatch for %s, "
		    "%d instead of %d\n", __func__, if_name(ifp),
		    s->packets_in, m_cnt);
	}

	if (s == NULL) {
		bzero(&_s, sizeof(_s));
		s = &_s;
	} else {
		_s = *s;
	}
	_s.packets_in = m_cnt;
	_s.bytes_in = m_size;

	if (ifp->if_xflags & IFXF_DISABLE_INPUT) {
		m_freem_list(m_head);

		os_atomic_add(&ifp->if_data.ifi_ipackets, _s.packets_in, relaxed);
		os_atomic_add(&ifp->if_data.ifi_ibytes, _s.bytes_in, relaxed);

		goto done;
	}

	err = (*input_func)(ifp, m_head, m_tail, s, poll, current_thread());

done:
	if (ifp != lo_ifp) {
		/* Release the IO refcnt */
		ifnet_datamov_end(ifp);
	}

	return err;
}


static void
ifnet_start_common(struct ifnet *ifp, boolean_t resetfc, boolean_t ignore_delay)
{
	if (!(ifp->if_eflags & IFEF_TXSTART)) {
		return;
	}
	/*
	 * If the starter thread is inactive, signal it to do work,
	 * unless the interface is being flow controlled from below,
	 * e.g. a virtual interface being flow controlled by a real
	 * network interface beneath it, or it's been disabled via
	 * a call to ifnet_disable_output().
	 */
	lck_mtx_lock_spin(&ifp->if_start_lock);
	if (ignore_delay) {
		ifp->if_start_flags |= IFSF_NO_DELAY;
	}
	if (resetfc) {
		ifp->if_start_flags &= ~IFSF_FLOW_CONTROLLED;
	} else if (ifp->if_start_flags & IFSF_FLOW_CONTROLLED) {
		lck_mtx_unlock(&ifp->if_start_lock);
		return;
	}
	ifp->if_start_req++;
	if (!ifp->if_start_active && ifp->if_start_thread != THREAD_NULL &&
	    (resetfc || !(ifp->if_eflags & IFEF_ENQUEUE_MULTI) ||
	    IFCQ_LEN(ifp->if_snd) >= ifp->if_start_delay_qlen ||
	    ifp->if_start_delayed == 0)) {
		(void) wakeup_one((caddr_t)&ifp->if_start_thread);
	}
	lck_mtx_unlock(&ifp->if_start_lock);
}

void
ifnet_start(struct ifnet *ifp)
{
	ifnet_start_common(ifp, FALSE, FALSE);
}

void
ifnet_start_ignore_delay(struct ifnet *ifp)
{
	ifnet_start_common(ifp, FALSE, TRUE);
}

__attribute__((noreturn))
static void
ifnet_start_thread_func(void *v, wait_result_t w)
{
#pragma unused(w)
	ifnet_ref_t ifp = v;
	char thread_name[MAXTHREADNAMESIZE];

	/* Construct the name for this thread, and then apply it. */
	bzero(thread_name, sizeof(thread_name));
	(void) snprintf(thread_name, sizeof(thread_name),
	    "ifnet_start_%s", ifp->if_xname);
#if SKYWALK
	/* override name for native Skywalk interface */
	if (ifp->if_eflags & IFEF_SKYWALK_NATIVE) {
		(void) snprintf(thread_name, sizeof(thread_name),
		    "skywalk_doorbell_%s_tx", ifp->if_xname);
	}
#endif /* SKYWALK */
	ASSERT(ifp->if_start_thread == current_thread());
	thread_set_thread_name(current_thread(), __unsafe_null_terminated_from_indexable(thread_name));

	/*
	 * Treat the dedicated starter thread for lo0 as equivalent to
	 * the driver workloop thread; if net_affinity is enabled for
	 * the main input thread, associate this starter thread to it
	 * by binding them with the same affinity tag.  This is done
	 * only once (as we only have one lo_ifp which never goes away.)
	 */
	if (ifp == lo_ifp) {
		struct dlil_threading_info *inp = dlil_main_input_thread;
		struct thread *__single tp = current_thread();
#if SKYWALK
		/* native skywalk loopback not yet implemented */
		VERIFY(!(ifp->if_eflags & IFEF_SKYWALK_NATIVE));
#endif /* SKYWALK */

		lck_mtx_lock(&inp->dlth_lock);
		if (inp->dlth_affinity) {
			u_int32_t tag = inp->dlth_affinity_tag;

			VERIFY(inp->dlth_driver_thread == THREAD_NULL);
			VERIFY(inp->dlth_poller_thread == THREAD_NULL);
			inp->dlth_driver_thread = tp;
			lck_mtx_unlock(&inp->dlth_lock);

			/* Associate this thread with the affinity tag */
			(void) dlil_affinity_set(tp, tag);
		} else {
			lck_mtx_unlock(&inp->dlth_lock);
		}
	}

	lck_mtx_lock(&ifp->if_start_lock);
	VERIFY(!ifp->if_start_embryonic && !ifp->if_start_active);
	(void) assert_wait(&ifp->if_start_thread, THREAD_UNINT);
	ifp->if_start_embryonic = 1;
	/* wake up once to get out of embryonic state */
	ifp->if_start_req++;
	(void) wakeup_one((caddr_t)&ifp->if_start_thread);
	lck_mtx_unlock(&ifp->if_start_lock);
	(void) thread_block_parameter(ifnet_start_thread_cont, ifp);
	/* NOTREACHED */
	__builtin_unreachable();
}

__attribute__((noreturn))
static void
ifnet_start_thread_cont(void *v, wait_result_t wres)
{
	ifnet_ref_t ifp = v;
	struct ifclassq *ifq = ifp->if_snd;

	lck_mtx_lock_spin(&ifp->if_start_lock);
	if (__improbable(wres == THREAD_INTERRUPTED ||
	    (ifp->if_start_flags & IFSF_TERMINATING) != 0)) {
		goto terminate;
	}

	if (__improbable(ifp->if_start_embryonic)) {
		ifp->if_start_embryonic = 0;
		lck_mtx_unlock(&ifp->if_start_lock);
		ifnet_decr_pending_thread_count(ifp);
		lck_mtx_lock_spin(&ifp->if_start_lock);
		goto skip;
	}

	ifp->if_start_active = 1;

	/*
	 * Keep on servicing until no more request.
	 */
	for (;;) {
		u_int32_t req = ifp->if_start_req;
		if ((ifp->if_start_flags & IFSF_NO_DELAY) == 0 &&
		    !IFCQ_IS_EMPTY(ifq) &&
		    (ifp->if_eflags & IFEF_ENQUEUE_MULTI) &&
		    ifp->if_start_delayed == 0 &&
		    IFCQ_LEN(ifq) < ifp->if_start_delay_qlen &&
		    (ifp->if_eflags & IFEF_DELAY_START)) {
			ifp->if_start_delayed = 1;
			ifnet_start_delayed++;
			break;
		}
		ifp->if_start_flags &= ~IFSF_NO_DELAY;
		ifp->if_start_delayed = 0;
		lck_mtx_unlock(&ifp->if_start_lock);

		/*
		 * If no longer attached, don't call start because ifp
		 * is being destroyed; else hold an IO refcnt to
		 * prevent the interface from being detached (will be
		 * released below.)
		 */
		if (!ifnet_datamov_begin(ifp)) {
			lck_mtx_lock_spin(&ifp->if_start_lock);
			break;
		}

		/* invoke the driver's start routine */
		((*ifp->if_start)(ifp));

		/*
		 * Release the io ref count taken above.
		 */
		ifnet_datamov_end(ifp);

		lck_mtx_lock_spin(&ifp->if_start_lock);

		/*
		 * If there's no pending request or if the
		 * interface has been disabled, we're done.
		 */
#define _IFSF_DISABLED  (IFSF_FLOW_CONTROLLED | IFSF_TERMINATING)
		if (req == ifp->if_start_req ||
		    (ifp->if_start_flags & _IFSF_DISABLED) != 0) {
			break;
		}
	}
skip:
	ifp->if_start_req = 0;
	ifp->if_start_active = 0;

#if SKYWALK
	/*
	 * Wakeup any waiters, e.g. any threads waiting to
	 * detach the interface from the flowswitch, etc.
	 */
	if (ifp->if_start_waiters != 0) {
		ifp->if_start_waiters = 0;
		wakeup(&ifp->if_start_waiters);
	}
#endif /* SKYWALK */
	if (__probable((ifp->if_start_flags & IFSF_TERMINATING) == 0)) {
		uint64_t deadline = TIMEOUT_WAIT_FOREVER;
		struct timespec delay_start_ts;
		struct timespec *ts = NULL;

		if (ts == NULL) {
			ts = ((IFCQ_TBR_IS_ENABLED(ifq) && !IFCQ_IS_EMPTY(ifq)) ?
			    &ifp->if_start_cycle : NULL);
		}

		if (ts == NULL && ifp->if_start_delayed == 1) {
			delay_start_ts.tv_sec = 0;
			delay_start_ts.tv_nsec = ifp->if_start_delay_timeout;
			ts = &delay_start_ts;
		}

		if (ts != NULL && ts->tv_sec == 0 && ts->tv_nsec == 0) {
			ts = NULL;
		}

		if (__improbable(ts != NULL)) {
			clock_interval_to_deadline((uint32_t)(ts->tv_nsec +
			    (ts->tv_sec * NSEC_PER_SEC)), 1, &deadline);
		}

		(void) assert_wait_deadline(&ifp->if_start_thread,
		    THREAD_UNINT, deadline);
		lck_mtx_unlock(&ifp->if_start_lock);
		(void) thread_block_parameter(ifnet_start_thread_cont, ifp);
		/* NOTREACHED */
	} else {
terminate:
		/* interface is detached? */
		ifnet_set_start_cycle(ifp, NULL);

		/* clear if_start_thread to allow termination to continue */
		ASSERT(ifp->if_start_thread != THREAD_NULL);
		ifp->if_start_thread = THREAD_NULL;
		wakeup((caddr_t)&ifp->if_start_thread);
		lck_mtx_unlock(&ifp->if_start_lock);

		if (dlil_verbose) {
			DLIL_PRINTF("%s: starter thread terminated\n",
			    if_name(ifp));
		}

		/* for the extra refcnt from kernel_thread_start() */
		thread_deallocate(current_thread());
		/* this is the end */
		thread_terminate(current_thread());
		/* NOTREACHED */
	}

	/* must never get here */
	VERIFY(0);
	/* NOTREACHED */
	__builtin_unreachable();
}

void
ifnet_set_start_cycle(struct ifnet *ifp, struct timespec *ts)
{
	if (ts == NULL) {
		bzero(&ifp->if_start_cycle, sizeof(ifp->if_start_cycle));
	} else {
		*(&ifp->if_start_cycle) = *ts;
	}

	if (ts != NULL && ts->tv_nsec != 0 && dlil_verbose) {
		DLIL_PRINTF("%s: restart interval set to %lu nsec\n",
		    if_name(ifp), ts->tv_nsec);
	}
}

static inline void
ifnet_poll_wakeup(struct ifnet *ifp)
{
	LCK_MTX_ASSERT(&ifp->if_poll_lock, LCK_MTX_ASSERT_OWNED);

	ifp->if_poll_req++;
	if (!(ifp->if_poll_flags & IF_POLLF_RUNNING) &&
	    ifp->if_poll_thread != THREAD_NULL) {
		wakeup_one((caddr_t)&ifp->if_poll_thread);
	}
}

void
ifnet_poll(struct ifnet *ifp)
{
	/*
	 * If the poller thread is inactive, signal it to do work.
	 */
	lck_mtx_lock_spin(&ifp->if_poll_lock);
	ifnet_poll_wakeup(ifp);
	lck_mtx_unlock(&ifp->if_poll_lock);
}

__attribute__((noreturn))
static void
ifnet_poll_thread_func(void *v, wait_result_t w)
{
#pragma unused(w)
	char thread_name[MAXTHREADNAMESIZE];
	ifnet_ref_t ifp = v;

	VERIFY(ifp->if_eflags & IFEF_RXPOLL);
	VERIFY(current_thread() == ifp->if_poll_thread);

	/* construct the name for this thread, and then apply it */
	bzero(thread_name, sizeof(thread_name));
	(void) snprintf(thread_name, sizeof(thread_name),
	    "ifnet_poller_%s", ifp->if_xname);
	thread_set_thread_name(ifp->if_poll_thread, __unsafe_null_terminated_from_indexable(thread_name));

	lck_mtx_lock(&ifp->if_poll_lock);
	VERIFY(!(ifp->if_poll_flags & (IF_POLLF_EMBRYONIC | IF_POLLF_RUNNING)));
	(void) assert_wait(&ifp->if_poll_thread, THREAD_UNINT);
	ifp->if_poll_flags |= IF_POLLF_EMBRYONIC;
	/* wake up once to get out of embryonic state */
	ifnet_poll_wakeup(ifp);
	lck_mtx_unlock(&ifp->if_poll_lock);
	(void) thread_block_parameter(ifnet_poll_thread_cont, ifp);
	/* NOTREACHED */
	__builtin_unreachable();
}

__attribute__((noreturn))
static void
ifnet_poll_thread_cont(void *v, wait_result_t wres)
{
	struct dlil_threading_info *inp;
	ifnet_ref_t ifp = v;
	struct ifnet_stat_increment_param s;
	struct timespec start_time;

	VERIFY(ifp->if_eflags & IFEF_RXPOLL);

	bzero(&s, sizeof(s));
	net_timerclear(&start_time);

	lck_mtx_lock_spin(&ifp->if_poll_lock);
	if (__improbable(wres == THREAD_INTERRUPTED ||
	    (ifp->if_poll_flags & IF_POLLF_TERMINATING) != 0)) {
		goto terminate;
	}

	inp = ifp->if_inp;
	VERIFY(inp != NULL);

	if (__improbable(ifp->if_poll_flags & IF_POLLF_EMBRYONIC)) {
		ifp->if_poll_flags &= ~IF_POLLF_EMBRYONIC;
		lck_mtx_unlock(&ifp->if_poll_lock);
		ifnet_decr_pending_thread_count(ifp);
		lck_mtx_lock_spin(&ifp->if_poll_lock);
		goto skip;
	}

	ifp->if_poll_flags |= IF_POLLF_RUNNING;

	/*
	 * Keep on servicing until no more request.
	 */
	for (;;) {
		mbuf_ref_t m_head, m_tail;
		u_int32_t m_lim, m_cnt, m_totlen;
		u_int16_t req = ifp->if_poll_req;

		m_lim = (ifp->if_rxpoll_plim != 0) ? ifp->if_rxpoll_plim :
		    MAX((qlimit(&inp->dlth_pkts)), (ifp->if_rxpoll_phiwat << 2));
		lck_mtx_unlock(&ifp->if_poll_lock);

		/*
		 * If no longer attached, there's nothing to do;
		 * else hold an IO refcnt to prevent the interface
		 * from being detached (will be released below.)
		 */
		if (!ifnet_is_attached(ifp, 1)) {
			lck_mtx_lock_spin(&ifp->if_poll_lock);
			break;
		}

		if (dlil_verbose > 1) {
			DLIL_PRINTF("%s: polling up to %d pkts, "
			    "pkts avg %d max %d, wreq avg %d, "
			    "bytes avg %d\n",
			    if_name(ifp), m_lim,
			    ifp->if_rxpoll_pavg, ifp->if_rxpoll_pmax,
			    ifp->if_rxpoll_wavg, ifp->if_rxpoll_bavg);
		}

		/* invoke the driver's input poll routine */
		((*ifp->if_input_poll)(ifp, 0, m_lim, &m_head, &m_tail,
		&m_cnt, &m_totlen));

		if (m_head != NULL) {
			VERIFY(m_tail != NULL && m_cnt > 0);

			if (dlil_verbose > 1) {
				DLIL_PRINTF("%s: polled %d pkts, "
				    "pkts avg %d max %d, wreq avg %d, "
				    "bytes avg %d\n",
				    if_name(ifp), m_cnt,
				    ifp->if_rxpoll_pavg, ifp->if_rxpoll_pmax,
				    ifp->if_rxpoll_wavg, ifp->if_rxpoll_bavg);
			}

			/* stats are required for extended variant */
			s.packets_in = m_cnt;
			s.bytes_in = m_totlen;

			(void) ifnet_input_common(ifp, m_head, m_tail,
			    &s, TRUE, TRUE);
		} else {
			if (dlil_verbose > 1) {
				DLIL_PRINTF("%s: no packets, "
				    "pkts avg %d max %d, wreq avg %d, "
				    "bytes avg %d\n",
				    if_name(ifp), ifp->if_rxpoll_pavg,
				    ifp->if_rxpoll_pmax, ifp->if_rxpoll_wavg,
				    ifp->if_rxpoll_bavg);
			}

			(void) ifnet_input_common(ifp, NULL, NULL,
			    NULL, FALSE, TRUE);
		}

		/* Release the io ref count */
		ifnet_decr_iorefcnt(ifp);

		lck_mtx_lock_spin(&ifp->if_poll_lock);

		/* if there's no pending request, we're done */
		if (req == ifp->if_poll_req ||
		    (ifp->if_poll_flags & IF_POLLF_TERMINATING) != 0) {
			break;
		}
	}
skip:
	ifp->if_poll_req = 0;
	ifp->if_poll_flags &= ~IF_POLLF_RUNNING;

	if (__probable((ifp->if_poll_flags & IF_POLLF_TERMINATING) == 0)) {
		uint64_t deadline = TIMEOUT_WAIT_FOREVER;
		struct timespec *ts;

		/*
		 * Wakeup N ns from now, else sleep indefinitely (ts = NULL)
		 * until ifnet_poll() is called again.
		 */
		ts = &ifp->if_poll_cycle;
		if (ts->tv_sec == 0 && ts->tv_nsec == 0) {
			ts = NULL;
		}

		if (ts != NULL) {
			clock_interval_to_deadline((uint32_t)(ts->tv_nsec +
			    (ts->tv_sec * NSEC_PER_SEC)), 1, &deadline);
		}

		(void) assert_wait_deadline(&ifp->if_poll_thread,
		    THREAD_UNINT, deadline);
		lck_mtx_unlock(&ifp->if_poll_lock);
		(void) thread_block_parameter(ifnet_poll_thread_cont, ifp);
		/* NOTREACHED */
	} else {
terminate:
		/* interface is detached (maybe while asleep)? */
		ifnet_set_poll_cycle(ifp, NULL);

		/* clear if_poll_thread to allow termination to continue */
		ASSERT(ifp->if_poll_thread != THREAD_NULL);
		ifp->if_poll_thread = THREAD_NULL;
		wakeup((caddr_t)&ifp->if_poll_thread);
		lck_mtx_unlock(&ifp->if_poll_lock);

		if (dlil_verbose) {
			DLIL_PRINTF("%s: poller thread terminated\n",
			    if_name(ifp));
		}

		/* for the extra refcnt from kernel_thread_start() */
		thread_deallocate(current_thread());
		/* this is the end */
		thread_terminate(current_thread());
		/* NOTREACHED */
	}

	/* must never get here */
	VERIFY(0);
	/* NOTREACHED */
	__builtin_unreachable();
}

void
ifnet_set_poll_cycle(struct ifnet *ifp, struct timespec *ts)
{
	if (ts == NULL) {
		bzero(&ifp->if_poll_cycle, sizeof(ifp->if_poll_cycle));
	} else {
		*(&ifp->if_poll_cycle) = *ts;
	}

	if (ts != NULL && ts->tv_nsec != 0 && dlil_verbose) {
		DLIL_PRINTF("%s: poll interval set to %lu nsec\n",
		    if_name(ifp), ts->tv_nsec);
	}
}

void
ifnet_purge(struct ifnet *ifp)
{
	if (ifp != NULL && (ifp->if_eflags & IFEF_TXSTART)) {
		if_qflush_snd(ifp, false);
	}
}

void
ifnet_update_sndq(struct ifclassq *ifq, cqev_t ev)
{
	IFCQ_LOCK_ASSERT_HELD(ifq);

	if (!(IFCQ_IS_READY(ifq))) {
		return;
	}

	if (IFCQ_TBR_IS_ENABLED(ifq)) {
		struct tb_profile tb = {
			.rate = ifq->ifcq_tbr.tbr_rate_raw,
			.percent = ifq->ifcq_tbr.tbr_percent, .depth = 0
		};
		(void) ifclassq_tbr_set(ifq, &tb, FALSE);
	}

	ifclassq_update(ifq, ev);
}

void
ifnet_update_rcv(struct ifnet *ifp, cqev_t ev)
{
	switch (ev) {
	case CLASSQ_EV_LINK_BANDWIDTH:
		if (net_rxpoll && (ifp->if_eflags & IFEF_RXPOLL)) {
			ifp->if_poll_update++;
		}
		break;

	default:
		break;
	}
}

errno_t
ifnet_set_output_sched_model(struct ifnet *ifp, u_int32_t model)
{
	struct ifclassq *ifq;
	u_int32_t omodel;
	errno_t err;

	if (ifp == NULL || model >= IFNET_SCHED_MODEL_MAX) {
		return EINVAL;
	} else if (!(ifp->if_eflags & IFEF_TXSTART)) {
		return ENXIO;
	}

	ifq = ifp->if_snd;
	IFCQ_LOCK(ifq);
	omodel = ifp->if_output_sched_model;
	ifp->if_output_sched_model = model;
	if ((err = ifclassq_pktsched_setup(ifq)) != 0) {
		ifp->if_output_sched_model = omodel;
	}
	IFCQ_UNLOCK(ifq);

	return err;
}

errno_t
ifnet_set_sndq_maxlen(struct ifnet *ifp, u_int32_t maxqlen)
{
	if (ifp == NULL) {
		return EINVAL;
	} else if (!(ifp->if_eflags & IFEF_TXSTART)) {
		return ENXIO;
	}

	ifclassq_set_maxlen(ifp->if_snd, maxqlen);

	return 0;
}

errno_t
ifnet_get_sndq_maxlen(struct ifnet *ifp, u_int32_t *maxqlen)
{
	if (ifp == NULL || maxqlen == NULL) {
		return EINVAL;
	} else if (!(ifp->if_eflags & IFEF_TXSTART)) {
		return ENXIO;
	}

	*maxqlen = ifclassq_get_maxlen(ifp->if_snd);

	return 0;
}

errno_t
ifnet_get_sndq_len(struct ifnet *ifp, u_int32_t *pkts)
{
	errno_t err;

	if (ifp == NULL || pkts == NULL) {
		err = EINVAL;
	} else if (!(ifp->if_eflags & IFEF_TXSTART)) {
		err = ENXIO;
	} else {
		err = ifclassq_get_len(ifp->if_snd, MBUF_SC_UNSPEC,
		    IF_CLASSQ_ALL_GRPS, pkts, NULL);
	}

	return err;
}

errno_t
ifnet_get_service_class_sndq_len(struct ifnet *ifp, mbuf_svc_class_t sc,
    u_int32_t *pkts, u_int32_t *bytes)
{
	errno_t err;

	if (ifp == NULL || !MBUF_VALID_SC(sc) ||
	    (pkts == NULL && bytes == NULL)) {
		err = EINVAL;
	} else if (!(ifp->if_eflags & IFEF_TXSTART)) {
		err = ENXIO;
	} else {
		err = ifclassq_get_len(ifp->if_snd, sc, IF_CLASSQ_ALL_GRPS,
		    pkts, bytes);
	}

	return err;
}

errno_t
ifnet_set_rcvq_maxlen(struct ifnet *ifp, u_int32_t maxqlen)
{
	struct dlil_threading_info *inp;

	if (ifp == NULL) {
		return EINVAL;
	} else if (!(ifp->if_eflags & IFEF_RXPOLL) || ifp->if_inp == NULL) {
		return ENXIO;
	}

	if (maxqlen == 0) {
		maxqlen = if_rcvq_maxlen;
	} else if (maxqlen < IF_RCVQ_MINLEN) {
		maxqlen = IF_RCVQ_MINLEN;
	}

	inp = ifp->if_inp;
	lck_mtx_lock(&inp->dlth_lock);
	qlimit(&inp->dlth_pkts) = maxqlen;
	lck_mtx_unlock(&inp->dlth_lock);

	return 0;
}

errno_t
ifnet_get_rcvq_maxlen(struct ifnet *ifp, u_int32_t *maxqlen)
{
	struct dlil_threading_info *inp;

	if (ifp == NULL || maxqlen == NULL) {
		return EINVAL;
	} else if (!(ifp->if_eflags & IFEF_RXPOLL) || ifp->if_inp == NULL) {
		return ENXIO;
	}

	inp = ifp->if_inp;
	lck_mtx_lock(&inp->dlth_lock);
	*maxqlen = qlimit(&inp->dlth_pkts);
	lck_mtx_unlock(&inp->dlth_lock);
	return 0;
}

void
ifnet_enqueue_multi_setup(struct ifnet *ifp, uint16_t delay_qlen,
    uint16_t delay_timeout)
{
	if (delay_qlen > 0 && delay_timeout > 0) {
		if_set_eflags(ifp, IFEF_ENQUEUE_MULTI);
		ifp->if_start_delay_qlen = MIN(100, delay_qlen);
		ifp->if_start_delay_timeout = min(20000, delay_timeout);
		/* convert timeout to nanoseconds */
		ifp->if_start_delay_timeout *= 1000;
		kprintf("%s: forced IFEF_ENQUEUE_MULTI qlen %u timeout %u\n",
		    ifp->if_xname, (uint32_t)delay_qlen,
		    (uint32_t)delay_timeout);
	} else {
		if_clear_eflags(ifp, IFEF_ENQUEUE_MULTI);
	}
}

/*
 * This function clears the DSCP bits in the IPV4/V6 header pointed to by buf.
 * While it's ok for buf to be not 32 bit aligned, the caller must ensure that
 * buf holds the full header.
 */
static __attribute__((noinline)) void
ifnet_mcast_clear_dscp(uint8_t *__indexable buf, uint8_t ip_ver)
{
	struct ip *ip;
	struct ip6_hdr *ip6;
	uint8_t lbuf[64] __attribute__((aligned(8)));
	uint8_t *p = buf;

	if (ip_ver == IPVERSION) {
		uint8_t old_tos;
		uint32_t sum;

		if (__improbable(!IP_HDR_ALIGNED_P(p))) {
			DTRACE_IP1(not__aligned__v4, uint8_t *, buf);
			bcopy(buf, lbuf, sizeof(struct ip));
			p = lbuf;
		}
		ip = (struct ip *)(void *)p;
		if (__probable((ip->ip_tos & ~IPTOS_ECN_MASK) == 0)) {
			return;
		}

		DTRACE_IP1(clear__v4, struct ip *, ip);
		old_tos = ip->ip_tos;
		ip->ip_tos &= IPTOS_ECN_MASK;
		sum = ip->ip_sum + htons(old_tos) - htons(ip->ip_tos);
		sum = (sum >> 16) + (sum & 0xffff);
		ip->ip_sum = (uint16_t)(sum & 0xffff);

		if (__improbable(p == lbuf)) {
			bcopy(lbuf, buf, sizeof(struct ip));
		}
	} else {
		uint32_t flow;
		ASSERT(ip_ver == IPV6_VERSION);

		if (__improbable(!IP_HDR_ALIGNED_P(p))) {
			DTRACE_IP1(not__aligned__v6, uint8_t *, buf);
			bcopy(buf, lbuf, sizeof(struct ip6_hdr));
			p = lbuf;
		}
		ip6 = (struct ip6_hdr *)(void *)p;
		flow = ntohl(ip6->ip6_flow);
		if (__probable((flow & IP6FLOW_DSCP_MASK) == 0)) {
			return;
		}

		DTRACE_IP1(clear__v6, struct ip6_hdr *, ip6);
		ip6->ip6_flow = htonl(flow & ~IP6FLOW_DSCP_MASK);

		if (__improbable(p == lbuf)) {
			bcopy(lbuf, buf, sizeof(struct ip6_hdr));
		}
	}
}

static inline errno_t
ifnet_enqueue_ifclassq(struct ifnet *ifp, struct ifclassq *ifcq,
    classq_pkt_t *p, boolean_t flush, boolean_t *pdrop)
{
#if SKYWALK
	volatile struct sk_nexusadv *nxadv = NULL;
#endif /* SKYWALK */
	volatile uint64_t *fg_ts = NULL;
	volatile uint64_t *rt_ts = NULL;
	struct timespec now;
	u_int64_t now_nsec = 0;
	int error = 0;
	uint8_t *mcast_buf = NULL;
	uint8_t ip_ver;
	uint32_t pktlen;

	ASSERT(ifp->if_eflags & IFEF_TXSTART);
#if SKYWALK
	/*
	 * If attached to flowswitch, grab pointers to the
	 * timestamp variables in the nexus advisory region.
	 */
	if ((ifp->if_capabilities & IFCAP_SKYWALK) && ifp->if_na != NULL &&
	    (nxadv = ifp->if_na->nifna_netif->nif_fsw_nxadv) != NULL) {
		fg_ts = &nxadv->nxadv_fg_sendts;
		rt_ts = &nxadv->nxadv_rt_sendts;
	}
#endif /* SKYWALK */

	/*
	 * If packet already carries a timestamp, either from dlil_output()
	 * or from flowswitch, use it here.  Otherwise, record timestamp.
	 * PKTF_TS_VALID is always cleared prior to entering classq, i.e.
	 * the timestamp value is used internally there.
	 */
	switch (p->cp_ptype) {
	case QP_MBUF:
#if SKYWALK
		/*
		 * Valid only for non-native (compat) Skywalk interface.
		 * If the data source uses packet, caller must convert
		 * it to mbuf first prior to calling this routine.
		 */
		ASSERT(!(ifp->if_eflags & IFEF_SKYWALK_NATIVE));
#endif /* SKYWALK */
		ASSERT(p->cp_mbuf->m_flags & M_PKTHDR);
		ASSERT(p->cp_mbuf->m_nextpkt == NULL);

		if (!(p->cp_mbuf->m_pkthdr.pkt_flags & PKTF_TS_VALID) ||
		    p->cp_mbuf->m_pkthdr.pkt_timestamp == 0) {
			nanouptime(&now);
			net_timernsec(&now, &now_nsec);
			p->cp_mbuf->m_pkthdr.pkt_timestamp = now_nsec;
		}
		p->cp_mbuf->m_pkthdr.pkt_flags &= ~PKTF_TS_VALID;
		/*
		 * If the packet service class is not background,
		 * update the timestamp to indicate recent activity
		 * on a foreground socket.
		 */
		if ((p->cp_mbuf->m_pkthdr.pkt_flags & PKTF_FLOW_ID) &&
		    p->cp_mbuf->m_pkthdr.pkt_flowsrc == FLOWSRC_INPCB) {
			if (!(p->cp_mbuf->m_pkthdr.pkt_flags &
			    PKTF_SO_BACKGROUND)) {
				ifp->if_fg_sendts = (uint32_t)_net_uptime;
				if (fg_ts != NULL) {
					*fg_ts = (uint32_t)_net_uptime;
				}
			}
			if (p->cp_mbuf->m_pkthdr.pkt_flags & PKTF_SO_REALTIME) {
				ifp->if_rt_sendts = (uint32_t)_net_uptime;
				if (rt_ts != NULL) {
					*rt_ts = (uint32_t)_net_uptime;
				}
			}
		}
		pktlen = m_pktlen(p->cp_mbuf);

		/*
		 * Some Wi-Fi AP implementations do not correctly handle
		 * multicast IP packets with DSCP bits set (radr://9331522).
		 * As a workaround we clear the DSCP bits but keep service
		 * class (rdar://51507725).
		 */
		if ((p->cp_mbuf->m_flags & M_MCAST) != 0 &&
		    IFNET_IS_WIFI_INFRA(ifp)) {
			size_t len = mbuf_len(p->cp_mbuf), hlen;
			struct ether_header *eh;
			boolean_t pullup = FALSE;
			uint16_t etype;

			if (__improbable(len < sizeof(struct ether_header))) {
				DTRACE_IP1(small__ether, size_t, len);
				if ((p->cp_mbuf = m_pullup(p->cp_mbuf,
				    sizeof(struct ether_header))) == NULL) {
					return ENOMEM;
				}
			}
			eh = mtod(p->cp_mbuf, struct ether_header *);
			etype = ntohs(eh->ether_type);
			if (etype == ETHERTYPE_IP) {
				hlen = sizeof(struct ether_header) +
				    sizeof(struct ip);
				if (len < hlen) {
					DTRACE_IP1(small__v4, size_t, len);
					pullup = TRUE;
				}
				ip_ver = IPVERSION;
			} else if (etype == ETHERTYPE_IPV6) {
				hlen = sizeof(struct ether_header) +
				    sizeof(struct ip6_hdr);
				if (len < hlen) {
					DTRACE_IP1(small__v6, size_t, len);
					pullup = TRUE;
				}
				ip_ver = IPV6_VERSION;
			} else {
				DTRACE_IP1(invalid__etype, uint16_t, etype);
				break;
			}
			if (pullup) {
				if ((p->cp_mbuf = m_pullup(p->cp_mbuf, (int)hlen)) ==
				    NULL) {
					return ENOMEM;
				}

				eh = mtod(p->cp_mbuf, struct ether_header *);
			}
			mcast_buf = (uint8_t *)(eh + 1);
			/*
			 * ifnet_mcast_clear_dscp() will finish the work below.
			 * Note that the pullups above ensure that mcast_buf
			 * points to a full IP header.
			 */
		}
		break;

#if SKYWALK
	case QP_PACKET:
		/*
		 * Valid only for native Skywalk interface.  If the data
		 * source uses mbuf, caller must convert it to packet first
		 * prior to calling this routine.
		 */
		ASSERT(ifp->if_eflags & IFEF_SKYWALK_NATIVE);
		if (!(p->cp_kpkt->pkt_pflags & PKT_F_TS_VALID) ||
		    p->cp_kpkt->pkt_timestamp == 0) {
			nanouptime(&now);
			net_timernsec(&now, &now_nsec);
			p->cp_kpkt->pkt_timestamp = now_nsec;
		}
		p->cp_kpkt->pkt_pflags &= ~PKT_F_TS_VALID;
		/*
		 * If the packet service class is not background,
		 * update the timestamps on the interface, as well as
		 * the ones in nexus-wide advisory to indicate recent
		 * activity on a foreground flow.
		 */
		if (!(p->cp_kpkt->pkt_pflags & PKT_F_BACKGROUND)) {
			ifp->if_fg_sendts = (uint32_t)_net_uptime;
			if (fg_ts != NULL) {
				*fg_ts = (uint32_t)_net_uptime;
			}
		}
		if (p->cp_kpkt->pkt_pflags & PKT_F_REALTIME) {
			ifp->if_rt_sendts = (uint32_t)_net_uptime;
			if (rt_ts != NULL) {
				*rt_ts = (uint32_t)_net_uptime;
			}
		}
		pktlen = p->cp_kpkt->pkt_length;

		/*
		 * Some Wi-Fi AP implementations do not correctly handle
		 * multicast IP packets with DSCP bits set (radr://9331522).
		 * As a workaround we clear the DSCP bits but keep service
		 * class (rdar://51507725).
		 */
		if ((p->cp_kpkt->pkt_link_flags & PKT_LINKF_MCAST) != 0 &&
		    IFNET_IS_WIFI_INFRA(ifp)) {
			uint8_t *baddr;
			struct ether_header *eh;
			uint16_t etype;

			MD_BUFLET_ADDR_ABS(p->cp_kpkt, baddr);
			baddr += p->cp_kpkt->pkt_headroom;
			if (__improbable(pktlen < sizeof(struct ether_header))) {
				DTRACE_IP1(pkt__small__ether, __kern_packet *,
				    p->cp_kpkt);
				break;
			}
			eh = (struct ether_header *)(void *)baddr;
			etype = ntohs(eh->ether_type);
			if (etype == ETHERTYPE_IP) {
				if (pktlen < sizeof(struct ether_header) +
				    sizeof(struct ip)) {
					DTRACE_IP1(pkt__small__v4, uint32_t,
					    pktlen);
					break;
				}
				ip_ver = IPVERSION;
			} else if (etype == ETHERTYPE_IPV6) {
				if (pktlen < sizeof(struct ether_header) +
				    sizeof(struct ip6_hdr)) {
					DTRACE_IP1(pkt__small__v6, uint32_t,
					    pktlen);
					break;
				}
				ip_ver = IPV6_VERSION;
			} else {
				DTRACE_IP1(pkt__invalid__etype, uint16_t,
				    etype);
				break;
			}
			mcast_buf = (uint8_t *)(eh + 1);
			/*
			 * ifnet_mcast_clear_dscp() will finish the work below.
			 * The checks above verify that the IP header is in the
			 * first buflet.
			 */
		}
		break;
#endif /* SKYWALK */

	default:
		VERIFY(0);
		/* NOTREACHED */
		__builtin_unreachable();
	}

	if (mcast_buf != NULL) {
		ifnet_mcast_clear_dscp(mcast_buf, ip_ver);
	}

	if (ifp->if_eflags & IFEF_ENQUEUE_MULTI) {
		if (now_nsec == 0) {
			nanouptime(&now);
			net_timernsec(&now, &now_nsec);
		}
		/*
		 * If the driver chose to delay start callback for
		 * coalescing multiple packets, Then use the following
		 * heuristics to make sure that start callback will
		 * be delayed only when bulk data transfer is detected.
		 * 1. number of packets enqueued in (delay_win * 2) is
		 * greater than or equal to the delay qlen.
		 * 2. If delay_start is enabled it will stay enabled for
		 * another 10 idle windows. This is to take into account
		 * variable RTT and burst traffic.
		 * 3. If the time elapsed since last enqueue is more
		 * than 200ms we disable delaying start callback. This is
		 * is to take idle time into account.
		 */
		u_int64_t dwin = (ifp->if_start_delay_timeout << 1);
		if (ifp->if_start_delay_swin > 0) {
			if ((ifp->if_start_delay_swin + dwin) > now_nsec) {
				ifp->if_start_delay_cnt++;
			} else if ((now_nsec - ifp->if_start_delay_swin)
			    >= (200 * 1000 * 1000)) {
				ifp->if_start_delay_swin = now_nsec;
				ifp->if_start_delay_cnt = 1;
				ifp->if_start_delay_idle = 0;
				if (ifp->if_eflags & IFEF_DELAY_START) {
					if_clear_eflags(ifp, IFEF_DELAY_START);
					ifnet_delay_start_disabled_increment();
				}
			} else {
				if (ifp->if_start_delay_cnt >=
				    ifp->if_start_delay_qlen) {
					if_set_eflags(ifp, IFEF_DELAY_START);
					ifp->if_start_delay_idle = 0;
				} else {
					if (ifp->if_start_delay_idle >= 10) {
						if_clear_eflags(ifp,
						    IFEF_DELAY_START);
						ifnet_delay_start_disabled_increment();
					} else {
						ifp->if_start_delay_idle++;
					}
				}
				ifp->if_start_delay_swin = now_nsec;
				ifp->if_start_delay_cnt = 1;
			}
		} else {
			ifp->if_start_delay_swin = now_nsec;
			ifp->if_start_delay_cnt = 1;
			ifp->if_start_delay_idle = 0;
			if_clear_eflags(ifp, IFEF_DELAY_START);
		}
	} else {
		if_clear_eflags(ifp, IFEF_DELAY_START);
	}

	/* enqueue the packet (caller consumes object) */
	error = ifclassq_enqueue(((ifcq != NULL) ? ifcq : ifp->if_snd), p, p,
	    1, pktlen, pdrop);

	/*
	 * Tell the driver to start dequeueing; do this even when the queue
	 * for the packet is suspended (EQSUSPENDED), as the driver could still
	 * be dequeueing from other unsuspended queues.
	 */
	if (!(ifp->if_eflags & IFEF_ENQUEUE_MULTI) &&
	    ((error == 0 && flush) || error == EQFULL || error == EQSUSPENDED)) {
		ifnet_start(ifp);
	}

	return error;
}

static inline errno_t
ifnet_enqueue_ifclassq_chain(struct ifnet *ifp, struct ifclassq *ifcq,
    classq_pkt_t *head, classq_pkt_t *tail, uint32_t cnt, uint32_t bytes,
    boolean_t flush, boolean_t *pdrop)
{
	int error;

	/* enqueue the packet (caller consumes object) */
	error = ifclassq_enqueue(ifcq != NULL ? ifcq : ifp->if_snd, head, tail,
	    cnt, bytes, pdrop);

	/*
	 * Tell the driver to start dequeueing; do this even when the queue
	 * for the packet is suspended (EQSUSPENDED), as the driver could still
	 * be dequeueing from other unsuspended queues.
	 */
	if ((error == 0 && flush) || error == EQFULL || error == EQSUSPENDED) {
		ifnet_start(ifp);
	}
	return error;
}

int
ifnet_enqueue_netem(void *handle, pktsched_pkt_t *__sized_by(n_pkts)pkts, uint32_t n_pkts)
{
	ifnet_ref_t ifp = handle;
	boolean_t pdrop;        /* dummy */
	uint32_t i;

	ASSERT(n_pkts >= 1);
	for (i = 0; i < n_pkts - 1; i++) {
		(void) ifnet_enqueue_ifclassq(ifp, NULL, &pkts[i].pktsched_pkt,
		    FALSE, &pdrop);
	}
	/* flush with the last packet */
	(void) ifnet_enqueue_ifclassq(ifp, NULL, &pkts[i].pktsched_pkt,
	    TRUE, &pdrop);

	return 0;
}

static inline errno_t
ifnet_enqueue_common(struct ifnet *ifp, struct ifclassq *ifcq,
    classq_pkt_t *pkt, boolean_t flush, boolean_t *pdrop)
{
	if (ifp->if_output_netem != NULL) {
		bool drop;
		errno_t error;
		error = netem_enqueue(ifp->if_output_netem, pkt, &drop);
		*pdrop = drop ? TRUE : FALSE;
		return error;
	} else {
		return ifnet_enqueue_ifclassq(ifp, ifcq, pkt, flush, pdrop);
	}
}

errno_t
ifnet_enqueue(struct ifnet *ifp, struct mbuf *m)
{
	uint32_t bytes = m_pktlen(m);
	struct mbuf *tail = m;
	uint32_t cnt = 1;
	boolean_t pdrop;

	while (tail->m_nextpkt) {
		VERIFY(tail->m_flags & M_PKTHDR);
		tail = tail->m_nextpkt;
		cnt++;
		bytes += m_pktlen(tail);
	}

	return ifnet_enqueue_mbuf_chain(ifp, m, tail, cnt, bytes, TRUE, &pdrop);
}

errno_t
ifnet_enqueue_mbuf(struct ifnet *ifp, struct mbuf *m, boolean_t flush,
    boolean_t *pdrop)
{
	classq_pkt_t pkt;

	m_add_hdr_crumb_interface_output(m, ifp->if_index, false);
	if (ifp == NULL || m == NULL || !(m->m_flags & M_PKTHDR) ||
	    m->m_nextpkt != NULL) {
		if (m != NULL) {
			m_drop_if(m, ifp, DROPTAP_FLAG_DIR_OUT, DROP_REASON_DLIL_ENQUEUE_INVALID, NULL, 0);
			*pdrop = TRUE;
		}
		return EINVAL;
	} else if (!(ifp->if_eflags & IFEF_TXSTART) ||
	    !IF_FULLY_ATTACHED(ifp)) {
		/* flag tested without lock for performance */
		m_drop_if(m, ifp, DROPTAP_FLAG_DIR_OUT, DROP_REASON_DLIL_ENQUEUE_IF_NOT_ATTACHED, NULL, 0);
		*pdrop = TRUE;
		return ENXIO;
	} else if (!(ifp->if_flags & IFF_UP)) {
		m_drop_if(m, ifp, DROPTAP_FLAG_DIR_OUT, DROP_REASON_DLIL_ENQUEUE_IF_NOT_UP, NULL, 0);
		*pdrop = TRUE;
		return ENETDOWN;
	}

	CLASSQ_PKT_INIT_MBUF(&pkt, m);
	return ifnet_enqueue_common(ifp, NULL, &pkt, flush, pdrop);
}

errno_t
ifnet_enqueue_mbuf_chain(struct ifnet *ifp, struct mbuf *m_head,
    struct mbuf *m_tail, uint32_t cnt, uint32_t bytes, boolean_t flush,
    boolean_t *pdrop)
{
	classq_pkt_t head, tail;

	m_add_hdr_crumb_interface_output(m_head, ifp->if_index, true);
	ASSERT(m_head != NULL);
	ASSERT((m_head->m_flags & M_PKTHDR) != 0);
	ASSERT(m_tail != NULL);
	ASSERT((m_tail->m_flags & M_PKTHDR) != 0);
	ASSERT(ifp != NULL);
	ASSERT((ifp->if_eflags & IFEF_TXSTART) != 0);

	if (!IF_FULLY_ATTACHED(ifp)) {
		/* flag tested without lock for performance */
		m_drop_list(m_head, ifp, DROPTAP_FLAG_DIR_OUT, DROP_REASON_DLIL_ENQUEUE_IF_NOT_ATTACHED, NULL, 0);
		*pdrop = TRUE;
		return ENXIO;
	} else if (!(ifp->if_flags & IFF_UP)) {
		m_drop_list(m_head, ifp, DROPTAP_FLAG_DIR_OUT, DROP_REASON_DLIL_ENQUEUE_IF_NOT_UP, NULL, 0);
		*pdrop = TRUE;
		return ENETDOWN;
	}

	CLASSQ_PKT_INIT_MBUF(&head, m_head);
	CLASSQ_PKT_INIT_MBUF(&tail, m_tail);
	return ifnet_enqueue_ifclassq_chain(ifp, NULL, &head, &tail, cnt, bytes,
	           flush, pdrop);
}

#if SKYWALK
static errno_t
ifnet_enqueue_pkt_common(struct ifnet *ifp, struct ifclassq *ifcq,
    struct __kern_packet *kpkt, boolean_t flush, boolean_t *pdrop)
{
	classq_pkt_t pkt;

	ASSERT(kpkt == NULL || kpkt->pkt_nextpkt == NULL);

	if (__improbable(ifp == NULL || kpkt == NULL)) {
		if (kpkt != NULL) {
			pp_free_packet(__DECONST(struct kern_pbufpool *,
			    kpkt->pkt_qum.qum_pp), SK_PTR_ADDR(kpkt));
			*pdrop = TRUE;
		}
		return EINVAL;
	} else if (__improbable(!(ifp->if_eflags & IFEF_TXSTART) ||
	    !IF_FULLY_ATTACHED(ifp))) {
		/* flag tested without lock for performance */
		pp_free_packet(__DECONST(struct kern_pbufpool *,
		    kpkt->pkt_qum.qum_pp), SK_PTR_ADDR(kpkt));
		*pdrop = TRUE;
		return ENXIO;
	} else if (__improbable(!(ifp->if_flags & IFF_UP))) {
		pp_free_packet(__DECONST(struct kern_pbufpool *,
		    kpkt->pkt_qum.qum_pp), SK_PTR_ADDR(kpkt));
		*pdrop = TRUE;
		return ENETDOWN;
	}

	CLASSQ_PKT_INIT_PACKET(&pkt, kpkt);
	return ifnet_enqueue_common(ifp, ifcq, &pkt, flush, pdrop);
}

errno_t
ifnet_enqueue_pkt(struct ifnet *ifp, struct __kern_packet *kpkt,
    boolean_t flush, boolean_t *pdrop)
{
	return ifnet_enqueue_pkt_common(ifp, NULL, kpkt, flush, pdrop);
}

errno_t
ifnet_enqueue_ifcq_pkt(struct ifnet *ifp, struct ifclassq *ifcq,
    struct __kern_packet *kpkt, boolean_t flush, boolean_t *pdrop)
{
	return ifnet_enqueue_pkt_common(ifp, ifcq, kpkt, flush, pdrop);
}

static errno_t
ifnet_enqueue_pkt_chain_common(struct ifnet *ifp, struct ifclassq *ifcq,
    struct __kern_packet *k_head, struct __kern_packet *k_tail, uint32_t cnt,
    uint32_t bytes, boolean_t flush, boolean_t *pdrop)
{
	classq_pkt_t head, tail;

	ASSERT(k_head != NULL);
	ASSERT(k_tail != NULL);
	ASSERT(ifp != NULL);
	ASSERT((ifp->if_eflags & IFEF_TXSTART) != 0);

	if (!IF_FULLY_ATTACHED(ifp)) {
		/* flag tested without lock for performance */
		pp_free_packet_chain(k_head, NULL);
		*pdrop = TRUE;
		return ENXIO;
	} else if (__improbable(!(ifp->if_flags & IFF_UP))) {
		pp_free_packet_chain(k_head, NULL);
		*pdrop = TRUE;
		return ENETDOWN;
	}

	CLASSQ_PKT_INIT_PACKET(&head, k_head);
	CLASSQ_PKT_INIT_PACKET(&tail, k_tail);
	return ifnet_enqueue_ifclassq_chain(ifp, ifcq, &head, &tail, cnt, bytes,
	           flush, pdrop);
}

errno_t
ifnet_enqueue_pkt_chain(struct ifnet *ifp, struct __kern_packet *k_head,
    struct __kern_packet *k_tail, uint32_t cnt, uint32_t bytes, boolean_t flush,
    boolean_t *pdrop)
{
	return ifnet_enqueue_pkt_chain_common(ifp, NULL, k_head, k_tail,
	           cnt, bytes, flush, pdrop);
}

errno_t
ifnet_enqueue_ifcq_pkt_chain(struct ifnet *ifp, struct ifclassq *ifcq,
    struct __kern_packet *k_head, struct __kern_packet *k_tail, uint32_t cnt,
    uint32_t bytes, boolean_t flush, boolean_t *pdrop)
{
	return ifnet_enqueue_pkt_chain_common(ifp, ifcq, k_head, k_tail,
	           cnt, bytes, flush, pdrop);
}
#endif /* SKYWALK */

errno_t
ifnet_dequeue(struct ifnet *ifp, struct mbuf **mp)
{
	errno_t rc;
	classq_pkt_t pkt = CLASSQ_PKT_INITIALIZER(pkt);

	if (ifp == NULL || mp == NULL) {
		return EINVAL;
	} else if (!(ifp->if_eflags & IFEF_TXSTART) ||
	    ifp->if_output_sched_model >= IFNET_SCHED_MODEL_MAX) {
		return ENXIO;
	}
	if (!ifnet_is_attached(ifp, 1)) {
		return ENXIO;
	}

#if SKYWALK
	ASSERT(!(ifp->if_eflags & IFEF_SKYWALK_NATIVE));
#endif /* SKYWALK */
	rc = ifclassq_dequeue(ifp->if_snd, 1, CLASSQ_DEQUEUE_MAX_BYTE_LIMIT,
	    &pkt, NULL, NULL, NULL, 0);
	VERIFY((pkt.cp_ptype == QP_MBUF) || (pkt.cp_mbuf == NULL));
	ifnet_decr_iorefcnt(ifp);
	*mp = pkt.cp_mbuf;
	m_add_hdr_crumb_interface_output(*mp, ifp->if_index, false);
	return rc;
}

errno_t
ifnet_dequeue_service_class(struct ifnet *ifp, mbuf_svc_class_t sc,
    struct mbuf **mp)
{
	errno_t rc;
	classq_pkt_t pkt = CLASSQ_PKT_INITIALIZER(pkt);

	if (ifp == NULL || mp == NULL || !MBUF_VALID_SC(sc)) {
		return EINVAL;
	} else if (!(ifp->if_eflags & IFEF_TXSTART) ||
	    ifp->if_output_sched_model >= IFNET_SCHED_MODEL_MAX) {
		return ENXIO;
	}
	if (!ifnet_is_attached(ifp, 1)) {
		return ENXIO;
	}

#if SKYWALK
	ASSERT(!(ifp->if_eflags & IFEF_SKYWALK_NATIVE));
#endif /* SKYWALK */
	rc = ifclassq_dequeue_sc(ifp->if_snd, sc, 1,
	    CLASSQ_DEQUEUE_MAX_BYTE_LIMIT, &pkt, NULL, NULL, NULL, 0);
	VERIFY((pkt.cp_ptype == QP_MBUF) || (pkt.cp_mbuf == NULL));
	ifnet_decr_iorefcnt(ifp);
	*mp = pkt.cp_mbuf;
	m_add_hdr_crumb_interface_output(*mp, ifp->if_index, false);
	return rc;
}

errno_t
ifnet_dequeue_multi(struct ifnet *ifp, u_int32_t pkt_limit,
    struct mbuf **head, struct mbuf **tail, u_int32_t *cnt, u_int32_t *len)
{
	errno_t rc;
	classq_pkt_t pkt_head = CLASSQ_PKT_INITIALIZER(pkt_head);
	classq_pkt_t pkt_tail = CLASSQ_PKT_INITIALIZER(pkt_tail);

	if (ifp == NULL || head == NULL || pkt_limit < 1) {
		return EINVAL;
	} else if (!(ifp->if_eflags & IFEF_TXSTART) ||
	    ifp->if_output_sched_model >= IFNET_SCHED_MODEL_MAX) {
		return ENXIO;
	}
	if (!ifnet_is_attached(ifp, 1)) {
		return ENXIO;
	}

#if SKYWALK
	ASSERT(!(ifp->if_eflags & IFEF_SKYWALK_NATIVE));
#endif /* SKYWALK */
	rc = ifclassq_dequeue(ifp->if_snd, pkt_limit,
	    CLASSQ_DEQUEUE_MAX_BYTE_LIMIT, &pkt_head, &pkt_tail, cnt, len, 0);
	VERIFY((pkt_head.cp_ptype == QP_MBUF) || (pkt_head.cp_mbuf == NULL));
	ifnet_decr_iorefcnt(ifp);
	*head = pkt_head.cp_mbuf;
	m_add_hdr_crumb_interface_output(*head, ifp->if_index, false);
	if (tail != NULL) {
		*tail = pkt_tail.cp_mbuf;
	}
	return rc;
}

errno_t
ifnet_dequeue_multi_bytes(struct ifnet *ifp, u_int32_t byte_limit,
    struct mbuf **head, struct mbuf **tail, u_int32_t *cnt, u_int32_t *len)
{
	errno_t rc;
	classq_pkt_t pkt_head = CLASSQ_PKT_INITIALIZER(pkt_head);
	classq_pkt_t pkt_tail = CLASSQ_PKT_INITIALIZER(pkt_tail);

	if (ifp == NULL || head == NULL || byte_limit < 1) {
		return EINVAL;
	} else if (!(ifp->if_eflags & IFEF_TXSTART) ||
	    ifp->if_output_sched_model >= IFNET_SCHED_MODEL_MAX) {
		return ENXIO;
	}
	if (!ifnet_is_attached(ifp, 1)) {
		return ENXIO;
	}

#if SKYWALK
	ASSERT(!(ifp->if_eflags & IFEF_SKYWALK_NATIVE));
#endif /* SKYWALK */
	rc = ifclassq_dequeue(ifp->if_snd, CLASSQ_DEQUEUE_MAX_PKT_LIMIT,
	    byte_limit, &pkt_head, &pkt_tail, cnt, len, 0);
	VERIFY((pkt_head.cp_ptype == QP_MBUF) || (pkt_head.cp_mbuf == NULL));
	ifnet_decr_iorefcnt(ifp);
	*head = pkt_head.cp_mbuf;
	m_add_hdr_crumb_interface_output(*head, ifp->if_index, false);
	if (tail != NULL) {
		*tail = pkt_tail.cp_mbuf;
	}
	return rc;
}

errno_t
ifnet_dequeue_service_class_multi(struct ifnet *ifp, mbuf_svc_class_t sc,
    u_int32_t pkt_limit, struct mbuf **head, struct mbuf **tail, u_int32_t *cnt,
    u_int32_t *len)
{
	errno_t rc;
	classq_pkt_t pkt_head = CLASSQ_PKT_INITIALIZER(pkt_head);
	classq_pkt_t pkt_tail = CLASSQ_PKT_INITIALIZER(pkt_tail);

	if (ifp == NULL || head == NULL || pkt_limit < 1 ||
	    !MBUF_VALID_SC(sc)) {
		return EINVAL;
	} else if (!(ifp->if_eflags & IFEF_TXSTART) ||
	    ifp->if_output_sched_model >= IFNET_SCHED_MODEL_MAX) {
		return ENXIO;
	}
	if (!ifnet_is_attached(ifp, 1)) {
		return ENXIO;
	}

#if SKYWALK
	ASSERT(!(ifp->if_eflags & IFEF_SKYWALK_NATIVE));
#endif /* SKYWALK */
	rc = ifclassq_dequeue_sc(ifp->if_snd, sc, pkt_limit,
	    CLASSQ_DEQUEUE_MAX_BYTE_LIMIT, &pkt_head, &pkt_tail,
	    cnt, len, 0);
	VERIFY((pkt_head.cp_ptype == QP_MBUF) || (pkt_head.cp_mbuf == NULL));
	ifnet_decr_iorefcnt(ifp);
	*head = pkt_head.cp_mbuf;
	m_add_hdr_crumb_interface_output(*head, ifp->if_index, false);
	if (tail != NULL) {
		*tail = pkt_tail.cp_mbuf;
	}
	return rc;
}

#if XNU_TARGET_OS_OSX
errno_t
ifnet_framer_stub(struct ifnet *ifp, struct mbuf **m,
    const struct sockaddr *dest,
    IFNET_LLADDR_T dest_linkaddr,
    IFNET_FRAME_TYPE_T frame_type,
    u_int32_t *pre, u_int32_t *post)
{
	if (pre != NULL) {
		*pre = 0;
	}
	if (post != NULL) {
		*post = 0;
	}

	return ifp->if_framer_legacy(ifp, m, dest, dest_linkaddr, frame_type);
}
#endif /* XNU_TARGET_OS_OSX */

/* If ifp is set, we will increment the generation for the interface */
int
dlil_post_complete_msg(struct ifnet *ifp, struct kev_msg *event)
{
	if (ifp != NULL) {
		ifnet_increment_generation(ifp);
	}

#if NECP
	necp_update_all_clients();
#endif /* NECP */

	return kev_post_msg(event);
}

__private_extern__ void
dlil_post_sifflags_msg(struct ifnet * ifp)
{
	struct kev_msg ev_msg;
	struct net_event_data ev_data;

	bzero(&ev_data, sizeof(ev_data));
	bzero(&ev_msg, sizeof(ev_msg));
	ev_msg.vendor_code = KEV_VENDOR_APPLE;
	ev_msg.kev_class = KEV_NETWORK_CLASS;
	ev_msg.kev_subclass = KEV_DL_SUBCLASS;
	ev_msg.event_code = KEV_DL_SIFFLAGS;
	strlcpy(&ev_data.if_name[0], ifp->if_name, IFNAMSIZ);
	ev_data.if_family = ifp->if_family;
	ev_data.if_unit = (u_int32_t) ifp->if_unit;
	ev_msg.dv[0].data_length = sizeof(struct net_event_data);
	ev_msg.dv[0].data_ptr = &ev_data;
	ev_msg.dv[1].data_length = 0;
	dlil_post_complete_msg(ifp, &ev_msg);
}

#define TMP_IF_PROTO_ARR_SIZE   10
static int
dlil_event_internal(struct ifnet *ifp, struct kev_msg *event, bool update_generation)
{
	struct ifnet_filter *filter = NULL;
	struct if_proto *proto = NULL;
	int if_proto_count = 0;
	struct if_proto *tmp_ifproto_stack_arr[TMP_IF_PROTO_ARR_SIZE] = {NULL};
	struct if_proto **tmp_ifproto_arr = tmp_ifproto_stack_arr;
	int tmp_ifproto_arr_idx = 0;

	/*
	 * Pass the event to the interface filters
	 */
	lck_mtx_lock_spin(&ifp->if_flt_lock);
	/* prevent filter list from changing in case we drop the lock */
	if_flt_monitor_busy(ifp);
	TAILQ_FOREACH(filter, &ifp->if_flt_head, filt_next) {
		if (filter->filt_event != NULL) {
			lck_mtx_unlock(&ifp->if_flt_lock);

			filter->filt_event(filter->filt_cookie, ifp,
			    filter->filt_protocol, event);

			lck_mtx_lock_spin(&ifp->if_flt_lock);
		}
	}
	/* we're done with the filter list */
	if_flt_monitor_unbusy(ifp);
	lck_mtx_unlock(&ifp->if_flt_lock);

	/* Get an io ref count if the interface is attached */
	if (!ifnet_is_attached(ifp, 1)) {
		goto done;
	}

	/*
	 * An embedded tmp_list_entry in if_proto may still get
	 * over-written by another thread after giving up ifnet lock,
	 * therefore we are avoiding embedded pointers here.
	 */
	ifnet_lock_shared(ifp);
	if_proto_count = dlil_ifp_protolist(ifp, NULL, 0);
	if (if_proto_count) {
		int i;
		VERIFY(ifp->if_proto_hash != NULL);
		if (if_proto_count <= TMP_IF_PROTO_ARR_SIZE) {
			tmp_ifproto_arr = tmp_ifproto_stack_arr;
		} else {
			tmp_ifproto_arr = kalloc_type(struct if_proto *,
			    if_proto_count, Z_WAITOK | Z_ZERO);
			if (tmp_ifproto_arr == NULL) {
				ifnet_lock_done(ifp);
				goto cleanup;
			}
		}

		for (i = 0; i < PROTO_HASH_SLOTS; i++) {
			SLIST_FOREACH(proto, &ifp->if_proto_hash[i],
			    next_hash) {
				if_proto_ref(proto);
				tmp_ifproto_arr[tmp_ifproto_arr_idx] = proto;
				tmp_ifproto_arr_idx++;
			}
		}
		VERIFY(if_proto_count == tmp_ifproto_arr_idx);
	}
	ifnet_lock_done(ifp);

	for (tmp_ifproto_arr_idx = 0; tmp_ifproto_arr_idx < if_proto_count;
	    tmp_ifproto_arr_idx++) {
		proto = tmp_ifproto_arr[tmp_ifproto_arr_idx];
		VERIFY(proto != NULL);
		proto_media_event eventp =
		    (proto->proto_kpi == kProtoKPI_v1 ?
		    proto->kpi.v1.event :
		    proto->kpi.v2.event);

		if (eventp != NULL) {
			eventp(ifp, proto->protocol_family,
			    event);
		}
		if_proto_free(proto);
	}

cleanup:
	if (tmp_ifproto_arr != tmp_ifproto_stack_arr) {
		kfree_type(struct if_proto *, if_proto_count, tmp_ifproto_arr);
	}

	/* Pass the event to the interface */
	if (ifp->if_event != NULL) {
		ifp->if_event(ifp, event);
	}

	/* Release the io ref count */
	ifnet_decr_iorefcnt(ifp);
done:
	return dlil_post_complete_msg(update_generation ? ifp : NULL, event);
}

errno_t
ifnet_event(ifnet_t ifp, struct kern_event_msg *event)
{
	struct kev_msg kev_msg;
	int result = 0;

	if (ifp == NULL || event == NULL) {
		return EINVAL;
	}

	bzero(&kev_msg, sizeof(kev_msg));
	kev_msg.vendor_code = event->vendor_code;
	kev_msg.kev_class = event->kev_class;
	kev_msg.kev_subclass = event->kev_subclass;
	kev_msg.event_code = event->event_code;
	kev_msg.dv[0].data_ptr = &event->event_data;
	kev_msg.dv[0].data_length = event->total_size - KEV_MSG_HEADER_SIZE;
	kev_msg.dv[1].data_length = 0;

	result = dlil_event_internal(ifp, &kev_msg, TRUE);

	return result;
}

/* The following is used to enqueue work items for ifnet ioctl events */
static void ifnet_ioctl_event_callback(struct nwk_wq_entry *);

struct ifnet_ioctl_event {
	ifnet_ref_t ifp;
	u_long ioctl_code;
};

struct ifnet_ioctl_event_nwk_wq_entry {
	struct nwk_wq_entry nwk_wqe;
	struct ifnet_ioctl_event ifnet_ioctl_ev_arg;
};

void
ifnet_ioctl_async(struct ifnet *ifp, u_long ioctl_code)
{
	struct ifnet_ioctl_event_nwk_wq_entry *p_ifnet_ioctl_ev = NULL;
	bool compare_expected;

	/*
	 * Get an io ref count if the interface is attached.
	 * At this point it most likely is. We are taking a reference for
	 * deferred processing.
	 */
	if (!ifnet_is_attached(ifp, 1)) {
		os_log(OS_LOG_DEFAULT, "%s:%d %s Failed for ioctl %lu as interface "
		    "is not attached",
		    __func__, __LINE__, if_name(ifp), ioctl_code);
		return;
	}
	switch (ioctl_code) {
	case SIOCADDMULTI:
		compare_expected = false;
		if (!atomic_compare_exchange_strong(&ifp->if_mcast_add_signaled, &compare_expected, true)) {
			ifnet_decr_iorefcnt(ifp);
			return;
		}
		break;
	case SIOCDELMULTI:
		compare_expected = false;
		if (!atomic_compare_exchange_strong(&ifp->if_mcast_del_signaled, &compare_expected, true)) {
			ifnet_decr_iorefcnt(ifp);
			return;
		}
		break;
	default:
		os_log(OS_LOG_DEFAULT, "%s:%d %s unknown ioctl %lu",
		    __func__, __LINE__, if_name(ifp), ioctl_code);
		return;
	}

	p_ifnet_ioctl_ev = kalloc_type(struct ifnet_ioctl_event_nwk_wq_entry,
	    Z_WAITOK | Z_ZERO | Z_NOFAIL);

	p_ifnet_ioctl_ev->ifnet_ioctl_ev_arg.ifp = ifp;
	p_ifnet_ioctl_ev->ifnet_ioctl_ev_arg.ioctl_code = ioctl_code;
	p_ifnet_ioctl_ev->nwk_wqe.func = ifnet_ioctl_event_callback;
	nwk_wq_enqueue(&p_ifnet_ioctl_ev->nwk_wqe);
}

static void
ifnet_ioctl_event_callback(struct nwk_wq_entry *nwk_item)
{
	struct ifnet_ioctl_event_nwk_wq_entry *p_ev = __container_of(nwk_item,
	    struct ifnet_ioctl_event_nwk_wq_entry, nwk_wqe);

	ifnet_ref_t ifp = p_ev->ifnet_ioctl_ev_arg.ifp;
	u_long ioctl_code = p_ev->ifnet_ioctl_ev_arg.ioctl_code;
	int ret = 0;

	switch (ioctl_code) {
	case SIOCADDMULTI:
		atomic_store(&ifp->if_mcast_add_signaled, false);
		break;
	case SIOCDELMULTI:
		atomic_store(&ifp->if_mcast_del_signaled, false);
		break;
	}
	if ((ret = ifnet_ioctl(ifp, 0, ioctl_code, NULL)) != 0) {
		os_log(OS_LOG_DEFAULT, "%s:%d %s ifnet_ioctl returned %d for ioctl %lu",
		    __func__, __LINE__, if_name(ifp), ret, ioctl_code);
	} else if (dlil_verbose) {
		os_log(OS_LOG_DEFAULT, "%s:%d %s ifnet_ioctl returned successfully "
		    "for ioctl %lu",
		    __func__, __LINE__, if_name(ifp), ioctl_code);
	}
	ifnet_decr_iorefcnt(ifp);
	kfree_type(struct ifnet_ioctl_event_nwk_wq_entry, p_ev);
	return;
}

errno_t
ifnet_ioctl(ifnet_t ifp, protocol_family_t proto_fam, u_long ioctl_code,
    void *ioctl_arg)
{
	struct ifnet_filter *filter;
	int retval = EOPNOTSUPP;
	int result = 0;

	if (ifp == NULL || ioctl_code == 0) {
		return EINVAL;
	}

	/* Get an io ref count if the interface is attached */
	if (!ifnet_is_attached(ifp, 1)) {
		return EOPNOTSUPP;
	}

	/*
	 * Run the interface filters first.
	 * We want to run all filters before calling the protocol,
	 * interface family, or interface.
	 */
	lck_mtx_lock_spin(&ifp->if_flt_lock);
	/* prevent filter list from changing in case we drop the lock */
	if_flt_monitor_busy(ifp);
	TAILQ_FOREACH(filter, &ifp->if_flt_head, filt_next) {
		if (filter->filt_ioctl != NULL && (filter->filt_protocol == 0 ||
		    filter->filt_protocol == proto_fam)) {
			lck_mtx_unlock(&ifp->if_flt_lock);

			result = filter->filt_ioctl(filter->filt_cookie, ifp,
			    proto_fam, ioctl_code, ioctl_arg);

			lck_mtx_lock_spin(&ifp->if_flt_lock);

			/* Only update retval if no one has handled the ioctl */
			if (retval == EOPNOTSUPP || result == EJUSTRETURN) {
				if (result == ENOTSUP) {
					result = EOPNOTSUPP;
				}
				retval = result;
				if (retval != 0 && retval != EOPNOTSUPP) {
					/* we're done with the filter list */
					if_flt_monitor_unbusy(ifp);
					lck_mtx_unlock(&ifp->if_flt_lock);
					goto cleanup;
				}
			}
		}
	}
	/* we're done with the filter list */
	if_flt_monitor_unbusy(ifp);
	lck_mtx_unlock(&ifp->if_flt_lock);

	/* Allow the protocol to handle the ioctl */
	if (proto_fam != 0) {
		struct if_proto *proto;

		/* callee holds a proto refcnt upon success */
		ifnet_lock_shared(ifp);
		proto = find_attached_proto(ifp, proto_fam);
		ifnet_lock_done(ifp);
		if (proto != NULL) {
			proto_media_ioctl ioctlp =
			    (proto->proto_kpi == kProtoKPI_v1 ?
			    proto->kpi.v1.ioctl : proto->kpi.v2.ioctl);
			result = EOPNOTSUPP;
			if (ioctlp != NULL) {
				result = ioctlp(ifp, proto_fam, ioctl_code,
				    ioctl_arg);
			}
			if_proto_free(proto);

			/* Only update retval if no one has handled the ioctl */
			if (retval == EOPNOTSUPP || result == EJUSTRETURN) {
				if (result == ENOTSUP) {
					result = EOPNOTSUPP;
				}
				retval = result;
				if (retval && retval != EOPNOTSUPP) {
					goto cleanup;
				}
			}
		}
	}

	/* retval is either 0 or EOPNOTSUPP */

	/*
	 * Let the interface handle this ioctl.
	 * If it returns EOPNOTSUPP, ignore that, we may have
	 * already handled this in the protocol or family.
	 */
	if (ifp->if_ioctl) {
		result = (*ifp->if_ioctl)(ifp, ioctl_code, ioctl_arg);
	}

	/* Only update retval if no one has handled the ioctl */
	if (retval == EOPNOTSUPP || result == EJUSTRETURN) {
		if (result == ENOTSUP) {
			result = EOPNOTSUPP;
		}
		retval = result;
		if (retval && retval != EOPNOTSUPP) {
			goto cleanup;
		}
	}

cleanup:
	if (retval == EJUSTRETURN) {
		retval = 0;
	}

	ifnet_decr_iorefcnt(ifp);

	return retval;
}

__private_extern__ errno_t
dlil_set_bpf_tap(ifnet_t ifp, bpf_tap_mode mode, bpf_packet_func callback)
{
	errno_t error = 0;

	if (ifp->if_set_bpf_tap) {
		/* Get an io reference on the interface if it is attached */
		if (!ifnet_is_attached(ifp, 1)) {
			return ENXIO;
		}
		error = ifp->if_set_bpf_tap(ifp, mode, callback);
		ifnet_decr_iorefcnt(ifp);
	}
	return error;
}

errno_t
dlil_resolve_multi(struct ifnet *ifp, const struct sockaddr *proto_addr,
    struct sockaddr *ll_addr, size_t ll_len)
{
	errno_t result = EOPNOTSUPP;
	struct if_proto *proto;
	const struct sockaddr *verify;
	proto_media_resolve_multi resolvep;

	if (!ifnet_is_attached(ifp, 1)) {
		return result;
	}

	SOCKADDR_ZERO(ll_addr, ll_len);

	/* Call the protocol first; callee holds a proto refcnt upon success */
	ifnet_lock_shared(ifp);
	proto = find_attached_proto(ifp, proto_addr->sa_family);
	ifnet_lock_done(ifp);
	if (proto != NULL) {
		resolvep = (proto->proto_kpi == kProtoKPI_v1 ?
		    proto->kpi.v1.resolve_multi : proto->kpi.v2.resolve_multi);
		if (resolvep != NULL) {
			result = resolvep(ifp, proto_addr, SDL(ll_addr), ll_len);
		}
		if_proto_free(proto);
	}

	/* Let the interface verify the multicast address */
	if ((result == EOPNOTSUPP || result == 0) && ifp->if_check_multi) {
		if (result == 0) {
			verify = ll_addr;
		} else {
			verify = proto_addr;
		}
		result = ifp->if_check_multi(ifp, verify);
	}

	ifnet_decr_iorefcnt(ifp);
	return result;
}

__private_extern__ errno_t
dlil_send_arp_internal(ifnet_t ifp, u_short arpop,
    const struct sockaddr_dl *sender_hw, const struct sockaddr *sender_proto,
    const struct sockaddr_dl *target_hw, const struct sockaddr *target_proto)
{
	struct if_proto *proto;
	errno_t result = 0;

	if ((ifp->if_flags & IFF_NOARP) != 0) {
		result = ENOTSUP;
		goto done;
	}

	/* callee holds a proto refcnt upon success */
	ifnet_lock_shared(ifp);
	proto = find_attached_proto(ifp, target_proto->sa_family);
	ifnet_lock_done(ifp);
	if (proto == NULL) {
		result = ENOTSUP;
	} else {
		proto_media_send_arp    arpp;
		arpp = (proto->proto_kpi == kProtoKPI_v1 ?
		    proto->kpi.v1.send_arp : proto->kpi.v2.send_arp);
		if (arpp == NULL) {
			result = ENOTSUP;
		} else {
			switch (arpop) {
			case ARPOP_REQUEST:
				arpstat.txrequests++;
				if (target_hw != NULL) {
					arpstat.txurequests++;
				}
				break;
			case ARPOP_REPLY:
				arpstat.txreplies++;
				break;
			}
			result = arpp(ifp, arpop, sender_hw, sender_proto,
			    target_hw, target_proto);
		}
		if_proto_free(proto);
	}
done:
	return result;
}

static __inline__ int
_is_announcement(const struct sockaddr_in * sender_sin,
    const struct sockaddr_in * target_sin)
{
	if (target_sin == NULL || sender_sin == NULL) {
		return FALSE;
	}

	return sender_sin->sin_addr.s_addr == target_sin->sin_addr.s_addr;
}

__private_extern__ errno_t
dlil_send_arp(ifnet_t ifp, u_short arpop, const struct sockaddr_dl *sender_hw,
    const struct sockaddr *sender_proto, const struct sockaddr_dl *target_hw,
    const struct sockaddr *target_proto0, u_int32_t rtflags)
{
	errno_t result = 0;
	const struct sockaddr_in * sender_sin;
	const struct sockaddr_in * target_sin;
	struct sockaddr_inarp target_proto_sinarp;
	struct sockaddr *target_proto = __DECONST_SA(target_proto0);

	if (target_proto == NULL || sender_proto == NULL) {
		return EINVAL;
	}

	if (sender_proto->sa_family != target_proto->sa_family) {
		return EINVAL;
	}

	/*
	 * If the target is a (default) router, provide that
	 * information to the send_arp callback routine.
	 */
	if (rtflags & RTF_ROUTER) {
		SOCKADDR_COPY(target_proto, &target_proto_sinarp, sizeof(struct sockaddr_in));
		target_proto_sinarp.sin_other |= SIN_ROUTER;
		target_proto = SA(&target_proto_sinarp);
	}

	/*
	 * If this is an ARP request and the target IP is IPv4LL,
	 * send the request on all interfaces.  The exception is
	 * an announcement, which must only appear on the specific
	 * interface.
	 */
	sender_sin = SIN(sender_proto);
	target_sin = SIN(target_proto);
	if (target_proto->sa_family == AF_INET &&
	    IN_LINKLOCAL(ntohl(target_sin->sin_addr.s_addr)) &&
	    ipv4_ll_arp_aware != 0 && arpop == ARPOP_REQUEST &&
	    !_is_announcement(sender_sin, target_sin)) {
		u_int32_t       count;
		ifnet_ref_t     *__counted_by(count) ifp_list;
		u_int32_t       ifp_on;

		result = ENOTSUP;

		if (ifnet_list_get(IFNET_FAMILY_ANY, &ifp_list, &count) == 0) {
			for (ifp_on = 0; ifp_on < count; ifp_on++) {
				errno_t new_result;
				ifaddr_t source_hw = NULL;
				ifaddr_t source_ip = NULL;
				struct sockaddr_in source_ip_copy;
				ifnet_ref_t cur_ifp = ifp_list[ifp_on];

				/*
				 * Only arp on interfaces marked for IPv4LL
				 * ARPing.  This may mean that we don't ARP on
				 * the interface the subnet route points to.
				 */
				if (!(cur_ifp->if_eflags & IFEF_ARPLL)) {
					continue;
				}

				/* Find the source IP address */
				ifnet_lock_shared(cur_ifp);
				source_hw = cur_ifp->if_lladdr;
				TAILQ_FOREACH(source_ip, &cur_ifp->if_addrhead,
				    ifa_link) {
					IFA_LOCK(source_ip);
					if (source_ip->ifa_addr != NULL &&
					    source_ip->ifa_addr->sa_family ==
					    AF_INET) {
						/* Copy the source IP address */
						SOCKADDR_COPY(SIN(source_ip->ifa_addr), &source_ip_copy, sizeof(source_ip_copy));
						IFA_UNLOCK(source_ip);
						break;
					}
					IFA_UNLOCK(source_ip);
				}

				/* No IP Source, don't arp */
				if (source_ip == NULL) {
					ifnet_lock_done(cur_ifp);
					continue;
				}

				ifa_addref(source_hw);
				ifnet_lock_done(cur_ifp);

				/* Send the ARP */
				new_result = dlil_send_arp_internal(cur_ifp,
				    arpop, SDL(source_hw->ifa_addr),
				    SA(&source_ip_copy), NULL,
				    target_proto);

				ifa_remref(source_hw);
				if (result == ENOTSUP) {
					result = new_result;
				}
			}
			ifnet_list_free_counted_by(ifp_list, count);
		}
	} else {
		result = dlil_send_arp_internal(ifp, arpop, sender_hw,
		    sender_proto, target_hw, target_proto);
	}

	return result;
}

/*
 * Caller must hold ifnet head lock.
 */
static int
ifnet_lookup(struct ifnet *ifp)
{
	ifnet_ref_t _ifp;

	ifnet_head_lock_assert(LCK_RW_ASSERT_HELD);
	TAILQ_FOREACH(_ifp, &ifnet_head, if_link) {
		if (_ifp == ifp) {
			break;
		}
	}
	return _ifp != NULL;
}

/*
 * Caller has to pass a non-zero refio argument to get a
 * IO reference count. This will prevent ifnet_detach from
 * being called when there are outstanding io reference counts.
 */
int
ifnet_is_attached(struct ifnet *ifp, int refio)
{
	int ret;

	lck_mtx_lock_spin(&ifp->if_ref_lock);
	if ((ret = IF_FULLY_ATTACHED(ifp))) {
		if (refio > 0) {
			ifp->if_refio++;
		}
	}
	lck_mtx_unlock(&ifp->if_ref_lock);

	return ret;
}

void
ifnet_incr_pending_thread_count(struct ifnet *ifp)
{
	lck_mtx_lock_spin(&ifp->if_ref_lock);
	ifp->if_threads_pending++;
	lck_mtx_unlock(&ifp->if_ref_lock);
}

void
ifnet_decr_pending_thread_count(struct ifnet *ifp)
{
	lck_mtx_lock_spin(&ifp->if_ref_lock);
	VERIFY(ifp->if_threads_pending > 0);
	ifp->if_threads_pending--;
	if (ifp->if_threads_pending == 0) {
		wakeup(&ifp->if_threads_pending);
	}
	lck_mtx_unlock(&ifp->if_ref_lock);
}

/*
 * Caller must ensure the interface is attached; the assumption is that
 * there is at least an outstanding IO reference count held already.
 * Most callers would call ifnet_is_{attached,data_ready}() instead.
 */
void
ifnet_incr_iorefcnt(struct ifnet *ifp)
{
	lck_mtx_lock_spin(&ifp->if_ref_lock);
	VERIFY(IF_FULLY_ATTACHED(ifp));
	VERIFY(ifp->if_refio > 0);
	ifp->if_refio++;
	lck_mtx_unlock(&ifp->if_ref_lock);
}

__attribute__((always_inline))
static void
ifnet_decr_iorefcnt_locked(struct ifnet *ifp)
{
	LCK_MTX_ASSERT(&ifp->if_ref_lock, LCK_MTX_ASSERT_OWNED);

	VERIFY(ifp->if_refio > 0);
	VERIFY(ifp->if_refflags & (IFRF_ATTACHED | IFRF_DETACHING));

	ifp->if_refio--;
	VERIFY(ifp->if_refio != 0 || ifp->if_datamov == 0);

	/*
	 * if there are no more outstanding io references, wakeup the
	 * ifnet_detach thread if detaching flag is set.
	 */
	if (ifp->if_refio == 0 && (ifp->if_refflags & IFRF_DETACHING)) {
		wakeup(&(ifp->if_refio));
	}
}

void
ifnet_decr_iorefcnt(struct ifnet *ifp)
{
	lck_mtx_lock_spin(&ifp->if_ref_lock);
	ifnet_decr_iorefcnt_locked(ifp);
	lck_mtx_unlock(&ifp->if_ref_lock);
}

boolean_t
ifnet_datamov_begin(struct ifnet *ifp)
{
	boolean_t ret;

	lck_mtx_lock_spin(&ifp->if_ref_lock);
	if ((ret = IF_FULLY_ATTACHED_AND_READY(ifp))) {
		ifp->if_refio++;
		ifp->if_datamov++;
	}
	lck_mtx_unlock(&ifp->if_ref_lock);

	DTRACE_IP2(datamov__begin, struct ifnet *, ifp, boolean_t, ret);
	return ret;
}

void
ifnet_datamov_end(struct ifnet *ifp)
{
	lck_mtx_lock_spin(&ifp->if_ref_lock);
	VERIFY(ifp->if_datamov > 0);
	/*
	 * if there's no more thread moving data, wakeup any
	 * drainers that's blocked waiting for this.
	 */
	if (--ifp->if_datamov == 0 && ifp->if_drainers > 0) {
		DLIL_PRINTF("Waking up drainers on %s\n", if_name(ifp));
		DTRACE_IP1(datamov__drain__wake, struct ifnet *, ifp);
		wakeup(&(ifp->if_datamov));
	}
	ifnet_decr_iorefcnt_locked(ifp);
	lck_mtx_unlock(&ifp->if_ref_lock);

	DTRACE_IP1(datamov__end, struct ifnet *, ifp);
}

static void
ifnet_datamov_suspend_locked(struct ifnet *ifp)
{
	LCK_MTX_ASSERT(&ifp->if_ref_lock, LCK_MTX_ASSERT_OWNED);
	ifp->if_refio++;
	if (ifp->if_suspend++ == 0) {
		VERIFY(ifp->if_refflags & IFRF_READY);
		ifp->if_refflags &= ~IFRF_READY;
	}
}

void
ifnet_datamov_suspend(struct ifnet *ifp)
{
	lck_mtx_lock_spin(&ifp->if_ref_lock);
	VERIFY(ifp->if_refflags & (IFRF_ATTACHED | IFRF_DETACHING));
	ifnet_datamov_suspend_locked(ifp);
	lck_mtx_unlock(&ifp->if_ref_lock);
}

boolean_t
ifnet_datamov_suspend_if_needed(struct ifnet *ifp)
{
	lck_mtx_lock_spin(&ifp->if_ref_lock);
	VERIFY(ifp->if_refflags & (IFRF_ATTACHED | IFRF_DETACHING));
	if (ifp->if_suspend > 0) {
		lck_mtx_unlock(&ifp->if_ref_lock);
		return FALSE;
	}
	ifnet_datamov_suspend_locked(ifp);
	lck_mtx_unlock(&ifp->if_ref_lock);
	return TRUE;
}

void
ifnet_datamov_drain(struct ifnet *ifp)
{
	lck_mtx_lock(&ifp->if_ref_lock);
	VERIFY(ifp->if_refflags & (IFRF_ATTACHED | IFRF_DETACHING));
	/* data movement must already be suspended */
	VERIFY(ifp->if_suspend > 0);
	VERIFY(!(ifp->if_refflags & IFRF_READY));
	ifp->if_drainers++;
	while (ifp->if_datamov != 0) {
		DLIL_PRINTF("Waiting for data path(s) to quiesce on %s\n",
		    if_name(ifp));
		DTRACE_IP1(datamov__wait, struct ifnet *, ifp);
		(void) msleep(&(ifp->if_datamov), &ifp->if_ref_lock,
		    (PZERO - 1), __func__, NULL);
		DTRACE_IP1(datamov__wake, struct ifnet *, ifp);
	}
	VERIFY(!(ifp->if_refflags & IFRF_READY));
	VERIFY(ifp->if_drainers > 0);
	ifp->if_drainers--;
	lck_mtx_unlock(&ifp->if_ref_lock);

	/* purge the interface queues */
	if ((ifp->if_eflags & IFEF_TXSTART) != 0) {
		if_qflush_snd(ifp, false);
	}
}

void
ifnet_datamov_suspend_and_drain(struct ifnet *ifp)
{
	ifnet_datamov_suspend(ifp);
	ifnet_datamov_drain(ifp);
}

void
ifnet_datamov_resume(struct ifnet *ifp)
{
	lck_mtx_lock(&ifp->if_ref_lock);
	/* data movement must already be suspended */
	VERIFY(ifp->if_suspend > 0);
	if (--ifp->if_suspend == 0) {
		VERIFY(!(ifp->if_refflags & IFRF_READY));
		ifp->if_refflags |= IFRF_READY;
	}
	ifnet_decr_iorefcnt_locked(ifp);
	lck_mtx_unlock(&ifp->if_ref_lock);
}

static errno_t
dlil_attach_protocol(struct if_proto *proto,
    const struct ifnet_demux_desc *__counted_by(demux_count) demux_list, u_int32_t demux_count,
    uint32_t *proto_count)
{
	struct kev_dl_proto_data ev_pr_data;
	ifnet_ref_t ifp = proto->ifp;
	errno_t retval = 0;
	u_int32_t hash_value = proto_hash_value(proto->protocol_family);
	struct if_proto *prev_proto;
	struct if_proto *_proto;

	/* don't allow attaching anything but PF_BRIDGE to vmnet interfaces */
	if (IFNET_IS_VMNET(ifp) && proto->protocol_family != PF_BRIDGE) {
		return EINVAL;
	}

	if (!ifnet_is_attached(ifp, 1)) {
		os_log(OS_LOG_DEFAULT, "%s: %s is no longer attached",
		    __func__, if_name(ifp));
		return ENXIO;
	}
	/* callee holds a proto refcnt upon success */
	ifnet_lock_exclusive(ifp);
	_proto = find_attached_proto(ifp, proto->protocol_family);
	if (_proto != NULL) {
		ifnet_lock_done(ifp);
		if_proto_free(_proto);
		retval = EEXIST;
		goto ioref_done;
	}

	/*
	 * Call family module add_proto routine so it can refine the
	 * demux descriptors as it wishes.
	 */
	retval = ifp->if_add_proto(ifp, proto->protocol_family, demux_list,
	    demux_count);
	if (retval) {
		ifnet_lock_done(ifp);
		goto ioref_done;
	}

	/*
	 * Insert the protocol in the hash
	 */
	prev_proto = SLIST_FIRST(&ifp->if_proto_hash[hash_value]);
	while (prev_proto != NULL && SLIST_NEXT(prev_proto, next_hash) != NULL) {
		prev_proto = SLIST_NEXT(prev_proto, next_hash);
	}
	if (prev_proto) {
		SLIST_INSERT_AFTER(prev_proto, proto, next_hash);
	} else {
		SLIST_INSERT_HEAD(&ifp->if_proto_hash[hash_value],
		    proto, next_hash);
	}

	/* hold a proto refcnt for attach */
	if_proto_ref(proto);

	/*
	 * The reserved field carries the number of protocol still attached
	 * (subject to change)
	 */
	ev_pr_data.proto_family = proto->protocol_family;
	ev_pr_data.proto_remaining_count = dlil_ifp_protolist(ifp, NULL, 0);

	ifnet_lock_done(ifp);

	dlil_post_msg(ifp, KEV_DL_SUBCLASS, KEV_DL_PROTO_ATTACHED,
	    (struct net_event_data *)&ev_pr_data,
	    sizeof(struct kev_dl_proto_data), FALSE);
	if (proto_count != NULL) {
		*proto_count = ev_pr_data.proto_remaining_count;
	}
ioref_done:
	ifnet_decr_iorefcnt(ifp);
	return retval;
}

static void
dlil_handle_proto_attach(ifnet_t ifp, protocol_family_t protocol)
{
	/*
	 * A protocol has been attached, mark the interface up.
	 * This used to be done by configd.KernelEventMonitor, but that
	 * is inherently prone to races (rdar://problem/30810208).
	 */
	(void) ifnet_set_flags(ifp, IFF_UP, IFF_UP);
	(void) ifnet_ioctl(ifp, 0, SIOCSIFFLAGS, NULL);
	dlil_post_sifflags_msg(ifp);
#if SKYWALK
	switch (protocol) {
	case AF_INET:
	case AF_INET6:
		/* don't attach the flowswitch unless attaching IP */
		dlil_attach_flowswitch_nexus(ifp);
		break;
	default:
		break;
	}
#endif /* SKYWALK */
}

errno_t
ifnet_attach_protocol(ifnet_t ifp, protocol_family_t protocol,
    const struct ifnet_attach_proto_param *proto_details)
{
	int retval = 0;
	struct if_proto  *ifproto = NULL;
	uint32_t proto_count = 0;

	ifnet_head_lock_shared();
	if (ifp == NULL || protocol == 0 || proto_details == NULL) {
		retval = EINVAL;
		goto end;
	}
	/* Check that the interface is in the global list */
	if (!ifnet_lookup(ifp)) {
		retval = ENXIO;
		goto end;
	}

	ifproto = dlif_proto_alloc();

	/* refcnt held above during lookup */
	ifproto->ifp = ifp;
	ifproto->protocol_family = protocol;
	ifproto->proto_kpi = kProtoKPI_v1;
	ifproto->kpi.v1.input = proto_details->input;
	ifproto->kpi.v1.pre_output = proto_details->pre_output;
	ifproto->kpi.v1.event = proto_details->event;
	ifproto->kpi.v1.ioctl = proto_details->ioctl;
	ifproto->kpi.v1.detached = proto_details->detached;
	ifproto->kpi.v1.resolve_multi = proto_details->resolve;
	ifproto->kpi.v1.send_arp = proto_details->send_arp;

	retval = dlil_attach_protocol(ifproto,
	    proto_details->demux_list, proto_details->demux_count,
	    &proto_count);

end:
	if (retval == EEXIST) {
		/* already attached */
		if (dlil_verbose) {
			DLIL_PRINTF("%s: protocol %d already attached\n",
			    ifp != NULL ? if_name(ifp) : "N/A",
			    protocol);
		}
	} else if (retval != 0) {
		DLIL_PRINTF("%s: failed to attach v1 protocol %d (err=%d)\n",
		    ifp != NULL ? if_name(ifp) : "N/A", protocol, retval);
	} else if (dlil_verbose) {
		DLIL_PRINTF("%s: attached v1 protocol %d (count = %d)\n",
		    ifp != NULL ? if_name(ifp) : "N/A",
		    protocol, proto_count);
	}
	ifnet_head_done();
	if (retval == 0) {
		dlil_handle_proto_attach(ifp, protocol);
	} else if (ifproto != NULL) {
		dlif_proto_free(ifproto);
	}
	return retval;
}

errno_t
ifnet_attach_protocol_v2(ifnet_t ifp, protocol_family_t protocol,
    const struct ifnet_attach_proto_param_v2 *proto_details)
{
	int retval = 0;
	struct if_proto  *ifproto = NULL;
	uint32_t proto_count = 0;

	ifnet_head_lock_shared();
	if (ifp == NULL || protocol == 0 || proto_details == NULL) {
		retval = EINVAL;
		goto end;
	}
	/* Check that the interface is in the global list */
	if (!ifnet_lookup(ifp)) {
		retval = ENXIO;
		goto end;
	}

	ifproto = dlif_proto_alloc();

	/* refcnt held above during lookup */
	ifproto->ifp = ifp;
	ifproto->protocol_family = protocol;
	ifproto->proto_kpi = kProtoKPI_v2;
	ifproto->kpi.v2.input = proto_details->input;
	ifproto->kpi.v2.pre_output = proto_details->pre_output;
	ifproto->kpi.v2.event = proto_details->event;
	ifproto->kpi.v2.ioctl = proto_details->ioctl;
	ifproto->kpi.v2.detached = proto_details->detached;
	ifproto->kpi.v2.resolve_multi = proto_details->resolve;
	ifproto->kpi.v2.send_arp = proto_details->send_arp;

	retval = dlil_attach_protocol(ifproto,
	    proto_details->demux_list, proto_details->demux_count,
	    &proto_count);

end:
	if (retval == EEXIST) {
		/* already attached */
		if (dlil_verbose) {
			DLIL_PRINTF("%s: protocol %d already attached\n",
			    ifp != NULL ? if_name(ifp) : "N/A",
			    protocol);
		}
	} else if (retval != 0) {
		DLIL_PRINTF("%s: failed to attach v2 protocol %d (err=%d)\n",
		    ifp != NULL ? if_name(ifp) : "N/A", protocol, retval);
	} else if (dlil_verbose) {
		DLIL_PRINTF("%s: attached v2 protocol %d (count = %d)\n",
		    ifp != NULL ? if_name(ifp) : "N/A",
		    protocol, proto_count);
	}
	ifnet_head_done();
	if (retval == 0) {
		dlil_handle_proto_attach(ifp, protocol);
	} else if (ifproto != NULL) {
		dlif_proto_free(ifproto);
	}
	return retval;
}

errno_t
ifnet_detach_protocol(ifnet_t ifp, protocol_family_t proto_family)
{
	struct if_proto *proto = NULL;
	int     retval = 0;

	if (ifp == NULL || proto_family == 0) {
		retval = EINVAL;
		goto end;
	}

	ifnet_lock_exclusive(ifp);
	/* callee holds a proto refcnt upon success */
	proto = find_attached_proto(ifp, proto_family);
	if (proto == NULL) {
		retval = ENXIO;
		ifnet_lock_done(ifp);
		goto end;
	}

	/* call family module del_proto */
	if (ifp->if_del_proto) {
		ifp->if_del_proto(ifp, proto->protocol_family);
	}

	SLIST_REMOVE(&ifp->if_proto_hash[proto_hash_value(proto_family)],
	    proto, if_proto, next_hash);

	if (proto->proto_kpi == kProtoKPI_v1) {
		proto->kpi.v1.input = ifproto_media_input_v1;
		proto->kpi.v1.pre_output = ifproto_media_preout;
		proto->kpi.v1.event = ifproto_media_event;
		proto->kpi.v1.ioctl = ifproto_media_ioctl;
		proto->kpi.v1.resolve_multi = ifproto_media_resolve_multi;
		proto->kpi.v1.send_arp = ifproto_media_send_arp;
	} else {
		proto->kpi.v2.input = ifproto_media_input_v2;
		proto->kpi.v2.pre_output = ifproto_media_preout;
		proto->kpi.v2.event = ifproto_media_event;
		proto->kpi.v2.ioctl = ifproto_media_ioctl;
		proto->kpi.v2.resolve_multi = ifproto_media_resolve_multi;
		proto->kpi.v2.send_arp = ifproto_media_send_arp;
	}
	proto->detached = 1;
	ifnet_lock_done(ifp);

	if (dlil_verbose) {
		DLIL_PRINTF("%s: detached %s protocol %d\n", if_name(ifp),
		    (proto->proto_kpi == kProtoKPI_v1) ?
		    "v1" : "v2", proto_family);
	}

	/* release proto refcnt held during protocol attach */
	if_proto_free(proto);

	/*
	 * Release proto refcnt held during lookup; the rest of
	 * protocol detach steps will happen when the last proto
	 * reference is released.
	 */
	if_proto_free(proto);

end:
	return retval;
}

static errno_t
ifproto_media_input_v1(struct ifnet *ifp, protocol_family_t protocol,
    struct mbuf *packet, char *header)
{
#pragma unused(ifp, protocol, packet, header)
	return ENXIO;
}

static errno_t
ifproto_media_input_v2(struct ifnet *ifp, protocol_family_t protocol,
    struct mbuf *packet)
{
#pragma unused(ifp, protocol, packet)
	return ENXIO;
}

static errno_t
ifproto_media_preout(struct ifnet *ifp, protocol_family_t protocol,
    mbuf_t *packet, const struct sockaddr *dest, void *route,
    IFNET_FRAME_TYPE_RW_T frame_type, IFNET_LLADDR_RW_T link_layer_dest)
{
#pragma unused(ifp, protocol, packet, dest, route, frame_type, link_layer_dest)
	return ENXIO;
}

static void
ifproto_media_event(struct ifnet *ifp, protocol_family_t protocol,
    const struct kev_msg *event)
{
#pragma unused(ifp, protocol, event)
}

static errno_t
ifproto_media_ioctl(struct ifnet *ifp, protocol_family_t protocol,
    unsigned long command, void *argument)
{
#pragma unused(ifp, protocol, command, argument)
	return ENXIO;
}

static errno_t
ifproto_media_resolve_multi(ifnet_t ifp, const struct sockaddr *proto_addr,
    struct sockaddr_dl *out_ll, size_t ll_len)
{
#pragma unused(ifp, proto_addr, out_ll, ll_len)
	return ENXIO;
}

static errno_t
ifproto_media_send_arp(struct ifnet *ifp, u_short arpop,
    const struct sockaddr_dl *sender_hw, const struct sockaddr *sender_proto,
    const struct sockaddr_dl *target_hw, const struct sockaddr *target_proto)
{
#pragma unused(ifp, arpop, sender_hw, sender_proto, target_hw, target_proto)
	return ENXIO;
}

extern int if_next_index(void);
extern int tcp_ecn_outbound;

void
dlil_ifclassq_setup(struct ifnet *ifp, struct ifclassq *ifcq)
{
	uint32_t sflags = 0;
	int err;

	if (if_flowadv) {
		sflags |= PKTSCHEDF_QALG_FLOWCTL;
	}

	if (if_delaybased_queue) {
		sflags |= PKTSCHEDF_QALG_DELAYBASED;
	}

	if (ifp->if_output_sched_model ==
	    IFNET_SCHED_MODEL_DRIVER_MANAGED) {
		sflags |= PKTSCHEDF_QALG_DRIVER_MANAGED;
	}
	/* Inherit drop limit from the default queue */
	if (ifp->if_snd != ifcq) {
		IFCQ_PKT_DROP_LIMIT(ifcq) = IFCQ_PKT_DROP_LIMIT(ifp->if_snd);
	}
	/* Initialize transmit queue(s) */
	err = ifclassq_setup(ifcq, ifp, sflags);
	if (err != 0) {
		panic_plain("%s: ifp=%p couldn't initialize transmit queue; "
		    "err=%d", __func__, ifp, err);
		/* NOTREACHED */
	}
}

errno_t
ifnet_attach(ifnet_t ifp, const struct sockaddr_dl *ll_addr)
{
#if SKYWALK
	boolean_t netif_compat;
	if_nexus_netif  nexus_netif;
#endif /* SKYWALK */
	ifnet_ref_t tmp_if;
	struct ifaddr *ifa;
	struct if_data_internal if_data_saved;
	struct dlil_ifnet *dl_if = (struct dlil_ifnet *)ifp;
	struct dlil_threading_info *dl_inp;
	thread_continue_t thfunc = NULL;
	int err;

	if (ifp == NULL) {
		return EINVAL;
	}

	/*
	 * Serialize ifnet attach using dlil_ifnet_lock, in order to
	 * prevent the interface from being configured while it is
	 * embryonic, as ifnet_head_lock is dropped and reacquired
	 * below prior to marking the ifnet with IFRF_ATTACHED.
	 */
	dlil_if_lock();
	ifnet_head_lock_exclusive();
	/* Verify we aren't already on the list */
	TAILQ_FOREACH(tmp_if, &ifnet_head, if_link) {
		if (tmp_if == ifp) {
			ifnet_head_done();
			dlil_if_unlock();
			return EEXIST;
		}
	}

	lck_mtx_lock_spin(&ifp->if_ref_lock);
	if (!(ifp->if_refflags & IFRF_EMBRYONIC)) {
		panic_plain("%s: flags mismatch (embryonic not set) ifp=%p",
		    __func__, ifp);
		/* NOTREACHED */
	}
	lck_mtx_unlock(&ifp->if_ref_lock);

	ifnet_lock_exclusive(ifp);

	/* Sanity check */
	VERIFY(ifp->if_detaching_link.tqe_next == NULL);
	VERIFY(ifp->if_detaching_link.tqe_prev == NULL);
	VERIFY(ifp->if_threads_pending == 0);

	if (ll_addr != NULL) {
		if (ifp->if_addrlen == 0) {
			ifp->if_addrlen = ll_addr->sdl_alen;
		} else if (ll_addr->sdl_alen != ifp->if_addrlen) {
			ifnet_lock_done(ifp);
			ifnet_head_done();
			dlil_if_unlock();
			return EINVAL;
		}
	}

	/*
	 * Allow interfaces without protocol families to attach
	 * only if they have the necessary fields filled out.
	 */
	if (ifp->if_add_proto == NULL || ifp->if_del_proto == NULL) {
		DLIL_PRINTF("%s: Attempt to attach interface without "
		    "family module - %d\n", __func__, ifp->if_family);
		ifnet_lock_done(ifp);
		ifnet_head_done();
		dlil_if_unlock();
		return ENODEV;
	}

	/* Allocate protocol hash table */
	VERIFY(ifp->if_proto_hash == NULL);
	ifp->if_proto_hash = kalloc_type(struct proto_hash_entry,
	    PROTO_HASH_SLOTS, Z_WAITOK | Z_ZERO | Z_NOFAIL);
	ifp->if_proto_hash_count = PROTO_HASH_SLOTS;

	lck_mtx_lock_spin(&ifp->if_flt_lock);
	VERIFY(TAILQ_EMPTY(&ifp->if_flt_head));
	TAILQ_INIT(&ifp->if_flt_head);
	VERIFY(ifp->if_flt_busy == 0);
	VERIFY(ifp->if_flt_waiters == 0);
	VERIFY(ifp->if_flt_non_os_count == 0);
	VERIFY(ifp->if_flt_no_tso_count == 0);
	lck_mtx_unlock(&ifp->if_flt_lock);

	if (!(dl_if->dl_if_flags & DLIF_REUSE)) {
		VERIFY(LIST_EMPTY(&ifp->if_multiaddrs));
		LIST_INIT(&ifp->if_multiaddrs);
	}

	VERIFY(ifp->if_allhostsinm == NULL);
	VERIFY(TAILQ_EMPTY(&ifp->if_addrhead));
	TAILQ_INIT(&ifp->if_addrhead);

	if (ifp->if_index == 0) {
		int idx = if_next_index();

		/*
		 * Since we exhausted the list of
		 * if_index's, try to find an empty slot
		 * in ifindex2ifnet.
		 */
		if (idx == -1 && if_index >= UINT16_MAX) {
			for (int i = 1; i < if_index; i++) {
				if (ifindex2ifnet[i] == NULL &&
				    ifnet_addrs[i - 1] == NULL) {
					idx = i;
					break;
				}
			}
		}
		if (idx == -1) {
			ifp->if_index = 0;
			ifnet_lock_done(ifp);
			ifnet_head_done();
			dlil_if_unlock();
			return ENOBUFS;
		}
		ifp->if_index = (uint16_t)idx;

		/* the lladdr passed at attach time is the permanent address */
		if (ll_addr != NULL && ifp->if_type == IFT_ETHER &&
		    ll_addr->sdl_alen == ETHER_ADDR_LEN) {
			bcopy(CONST_LLADDR(ll_addr),
			    dl_if->dl_if_permanent_ether,
			    ETHER_ADDR_LEN);
			dl_if->dl_if_permanent_ether_is_set = 1;
		}
	}
	/* There should not be anything occupying this slot */
	VERIFY(ifindex2ifnet[ifp->if_index] == NULL);

	/* allocate (if needed) and initialize a link address */
	ifa = dlil_alloc_lladdr(ifp, ll_addr);
	if (ifa == NULL) {
		ifnet_lock_done(ifp);
		ifnet_head_done();
		dlil_if_unlock();
		return ENOBUFS;
	}

	VERIFY(ifnet_addrs[ifp->if_index - 1] == NULL);
	ifnet_addrs[ifp->if_index - 1] = ifa;

	/* make this address the first on the list */
	IFA_LOCK(ifa);
	/* hold a reference for ifnet_addrs[] */
	ifa_addref(ifa);
	/* if_attach_link_ifa() holds a reference for ifa_link */
	if_attach_link_ifa(ifp, ifa);
	IFA_UNLOCK(ifa);

	TAILQ_INSERT_TAIL(&ifnet_head, ifp, if_link);
	ifindex2ifnet[ifp->if_index] = ifp;

	/* Hold a reference to the underlying dlil_ifnet */
	ifnet_reference(ifp);

	/* Clear stats (save and restore other fields that we care) */
	if_data_saved = ifp->if_data;
	bzero(&ifp->if_data, sizeof(ifp->if_data));
	ifp->if_data.ifi_type = if_data_saved.ifi_type;
	ifp->if_data.ifi_typelen = if_data_saved.ifi_typelen;
	ifp->if_data.ifi_physical = if_data_saved.ifi_physical;
	ifp->if_data.ifi_addrlen = if_data_saved.ifi_addrlen;
	ifp->if_data.ifi_hdrlen = if_data_saved.ifi_hdrlen;
	ifp->if_data.ifi_mtu = if_data_saved.ifi_mtu;
	ifp->if_data.ifi_baudrate = if_data_saved.ifi_baudrate;
	ifp->if_data.ifi_hwassist = if_data_saved.ifi_hwassist;
	ifp->if_data.ifi_tso_v4_mtu = if_data_saved.ifi_tso_v4_mtu;
	ifp->if_data.ifi_tso_v6_mtu = if_data_saved.ifi_tso_v6_mtu;
	ifnet_touch_lastchange(ifp);

	VERIFY(ifp->if_output_sched_model == IFNET_SCHED_MODEL_NORMAL ||
	    ifp->if_output_sched_model == IFNET_SCHED_MODEL_DRIVER_MANAGED ||
	    ifp->if_output_sched_model == IFNET_SCHED_MODEL_FQ_CODEL);

	dlil_ifclassq_setup(ifp, ifp->if_snd);

	/* Sanity checks on the input thread storage */
	dl_inp = &dl_if->dl_if_inpstorage;
	bzero(&dl_inp->dlth_stats, sizeof(dl_inp->dlth_stats));
	VERIFY(dl_inp->dlth_flags == 0);
	VERIFY(dl_inp->dlth_wtot == 0);
	VERIFY(dl_inp->dlth_ifp == NULL);
	VERIFY(qhead(&dl_inp->dlth_pkts) == NULL && qempty(&dl_inp->dlth_pkts));
	VERIFY(qlimit(&dl_inp->dlth_pkts) == 0);
	VERIFY(!dl_inp->dlth_affinity);
	VERIFY(ifp->if_inp == NULL);
	VERIFY(dl_inp->dlth_thread == THREAD_NULL);
	VERIFY(dl_inp->dlth_strategy == NULL);
	VERIFY(dl_inp->dlth_driver_thread == THREAD_NULL);
	VERIFY(dl_inp->dlth_poller_thread == THREAD_NULL);
	VERIFY(dl_inp->dlth_affinity_tag == 0);

#if IFNET_INPUT_SANITY_CHK
	VERIFY(dl_inp->dlth_pkts_cnt == 0);
#endif /* IFNET_INPUT_SANITY_CHK */

	VERIFY(ifp->if_poll_thread == THREAD_NULL);
	dlil_reset_rxpoll_params(ifp);
	/*
	 * A specific DLIL input thread is created per non-loopback interface.
	 */
	if (ifp->if_family != IFNET_FAMILY_LOOPBACK) {
		ifp->if_inp = dl_inp;
		ifnet_incr_pending_thread_count(ifp);
		err = dlil_create_input_thread(ifp, ifp->if_inp, &thfunc);
		if (err == ENODEV) {
			VERIFY(thfunc == NULL);
			ifnet_decr_pending_thread_count(ifp);
		} else if (err != 0) {
			panic_plain("%s: ifp=%p couldn't get an input thread; "
			    "err=%d", __func__, ifp, err);
			/* NOTREACHED */
		}
	}
	/*
	 * If the driver supports the new transmit model, calculate flow hash
	 * and create a workloop starter thread to invoke the if_start callback
	 * where the packets may be dequeued and transmitted.
	 */
	if (ifp->if_eflags & IFEF_TXSTART) {
		thread_precedence_policy_data_t info;
		__unused kern_return_t kret;

		ifp->if_flowhash = ifnet_calc_flowhash(ifp);
		VERIFY(ifp->if_flowhash != 0);
		VERIFY(ifp->if_start_thread == THREAD_NULL);

		ifnet_set_start_cycle(ifp, NULL);
		ifp->if_start_active = 0;
		ifp->if_start_req = 0;
		ifp->if_start_flags = 0;
		VERIFY(ifp->if_start != NULL);
		ifnet_incr_pending_thread_count(ifp);
		if ((err = kernel_thread_start(ifnet_start_thread_func,
		    ifp, &ifp->if_start_thread)) != KERN_SUCCESS) {
			panic_plain("%s: "
			    "ifp=%p couldn't get a start thread; "
			    "err=%d", __func__, ifp, err);
			/* NOTREACHED */
		}
		bzero(&info, sizeof(info));
		info.importance = 1;
		kret = thread_policy_set(ifp->if_start_thread,
		    THREAD_PRECEDENCE_POLICY, (thread_policy_t)&info,
		    THREAD_PRECEDENCE_POLICY_COUNT);
		ASSERT(kret == KERN_SUCCESS);
	} else {
		ifp->if_flowhash = 0;
	}

	/* Reset polling parameters */
	ifnet_set_poll_cycle(ifp, NULL);
	ifp->if_poll_update = 0;
	ifp->if_poll_flags = 0;
	ifp->if_poll_req = 0;
	VERIFY(ifp->if_poll_thread == THREAD_NULL);

	/*
	 * If the driver supports the new receive model, create a poller
	 * thread to invoke if_input_poll callback where the packets may
	 * be dequeued from the driver and processed for reception.
	 * if the interface is netif compat then the poller thread is
	 * managed by netif.
	 */
	if (dlil_is_rxpoll_input(thfunc)) {
		thread_precedence_policy_data_t info;
		__unused kern_return_t kret;
#if SKYWALK
		VERIFY(!(ifp->if_eflags & IFEF_SKYWALK_NATIVE));
#endif /* SKYWALK */
		VERIFY(ifp->if_input_poll != NULL);
		VERIFY(ifp->if_input_ctl != NULL);
		ifnet_incr_pending_thread_count(ifp);
		if ((err = kernel_thread_start(ifnet_poll_thread_func, ifp,
		    &ifp->if_poll_thread)) != KERN_SUCCESS) {
			panic_plain("%s: ifp=%p couldn't get a poll thread; "
			    "err=%d", __func__, ifp, err);
			/* NOTREACHED */
		}
		bzero(&info, sizeof(info));
		info.importance = 1;
		kret = thread_policy_set(ifp->if_poll_thread,
		    THREAD_PRECEDENCE_POLICY, (thread_policy_t)&info,
		    THREAD_PRECEDENCE_POLICY_COUNT);
		ASSERT(kret == KERN_SUCCESS);
	}

	VERIFY(ifp->if_desc.ifd_maxlen == IF_DESCSIZE);
	VERIFY(ifp->if_desc.ifd_len == 0);
	VERIFY(ifp->if_desc.ifd_desc != NULL);

	/* Record attach PC stacktrace */
	ctrace_record(&((struct dlil_ifnet *)ifp)->dl_if_attach);

	ifp->if_updatemcasts = 0;
	if (!LIST_EMPTY(&ifp->if_multiaddrs)) {
		struct ifmultiaddr *ifma;
		LIST_FOREACH(ifma, &ifp->if_multiaddrs, ifma_link) {
			IFMA_LOCK(ifma);
			if (ifma->ifma_addr->sa_family == AF_LINK ||
			    ifma->ifma_addr->sa_family == AF_UNSPEC) {
				ifp->if_updatemcasts++;
			}
			IFMA_UNLOCK(ifma);
		}

		DLIL_PRINTF("%s: attached with %d suspended link-layer multicast "
		    "membership(s)\n", if_name(ifp),
		    ifp->if_updatemcasts);
	}

	/* Clear logging parameters */
	bzero(&ifp->if_log, sizeof(ifp->if_log));

	/* Clear foreground/realtime activity timestamps */
	ifp->if_fg_sendts = 0;
	ifp->if_rt_sendts = 0;

	/* Clear throughput estimates and radio type */
	ifp->if_estimated_up_bucket = 0;
	ifp->if_estimated_down_bucket = 0;
	ifp->if_radio_type = 0;
	ifp->if_radio_channel = 0;

	VERIFY(ifp->if_delegated.ifp == NULL);
	VERIFY(ifp->if_delegated.type == 0);
	VERIFY(ifp->if_delegated.family == 0);
	VERIFY(ifp->if_delegated.subfamily == 0);
	VERIFY(ifp->if_delegated.expensive == 0);
	VERIFY(ifp->if_delegated.constrained == 0);
	VERIFY(ifp->if_delegated.ultra_constrained == 0);

	VERIFY(ifp->if_agentids == NULL);
	VERIFY(ifp->if_agentcount == 0);

	/* Reset interface state */
	bzero(&ifp->if_interface_state, sizeof(ifp->if_interface_state));
	ifp->if_interface_state.valid_bitmask |=
	    IF_INTERFACE_STATE_INTERFACE_AVAILABILITY_VALID;
	ifp->if_interface_state.interface_availability =
	    IF_INTERFACE_STATE_INTERFACE_AVAILABLE;

	/* Initialize Link Quality Metric (loopback [lo0] is always good) */
	if (ifp == lo_ifp) {
		ifp->if_interface_state.lqm_state = IFNET_LQM_THRESH_GOOD;
		ifp->if_interface_state.valid_bitmask |=
		    IF_INTERFACE_STATE_LQM_STATE_VALID;
	} else {
		ifp->if_interface_state.lqm_state = IFNET_LQM_THRESH_UNKNOWN;
	}

	/*
	 * Enable ECN capability on this interface depending on the
	 * value of ECN global setting
	 */
	if (tcp_ecn_outbound == 2 && !IFNET_IS_CELLULAR(ifp)) {
		if_set_eflags(ifp, IFEF_ECN_ENABLE);
		if_clear_eflags(ifp, IFEF_ECN_DISABLE);
	}

	/*
	 * Built-in Cyclops always on policy for WiFi infra
	 */
	if (IFNET_IS_WIFI_INFRA(ifp) && net_qos_policy_wifi_enabled != 0) {
		errno_t error;

		error = if_set_qosmarking_mode(ifp,
		    IFRTYPE_QOSMARKING_FASTLANE);
		if (error != 0) {
			DLIL_PRINTF("%s if_set_qosmarking_mode(%s) error %d\n",
			    __func__, ifp->if_xname, error);
		} else {
			if_set_eflags(ifp, IFEF_QOSMARKING_ENABLED);
#if (DEVELOPMENT || DEBUG)
			DLIL_PRINTF("%s fastlane enabled on %s\n",
			    __func__, ifp->if_xname);
#endif /* (DEVELOPMENT || DEBUG) */
		}
	}

	ifnet_lock_done(ifp);
	ifnet_head_done();

#if SKYWALK
	netif_compat = dlil_attach_netif_compat_nexus(ifp, &nexus_netif);
#endif /* SKYWALK */

	lck_mtx_lock(&ifp->if_cached_route_lock);
	/* Enable forwarding cached route */
	ifp->if_fwd_cacheok = 1;
	/* Clean up any existing cached routes */
	ROUTE_RELEASE(&ifp->if_fwd_route);
	bzero(&ifp->if_fwd_route, sizeof(ifp->if_fwd_route));
	ROUTE_RELEASE(&ifp->if_src_route);
	bzero(&ifp->if_src_route, sizeof(ifp->if_src_route));
	ROUTE_RELEASE(&ifp->if_src_route6);
	bzero(&ifp->if_src_route6, sizeof(ifp->if_src_route6));
	lck_mtx_unlock(&ifp->if_cached_route_lock);

	ifnet_llreach_ifattach(ifp, (dl_if->dl_if_flags & DLIF_REUSE));

	/*
	 * Allocate and attach IGMPv3/MLDv2 interface specific variables
	 * and trees; do this before the ifnet is marked as attached.
	 * The ifnet keeps the reference to the info structures even after
	 * the ifnet is detached, since the network-layer records still
	 * refer to the info structures even after that.  This also
	 * makes it possible for them to still function after the ifnet
	 * is recycled or reattached.
	 */
#if INET
	if (IGMP_IFINFO(ifp) == NULL) {
		IGMP_IFINFO(ifp) = igmp_domifattach(ifp, Z_WAITOK);
		VERIFY(IGMP_IFINFO(ifp) != NULL);
	} else {
		VERIFY(IGMP_IFINFO(ifp)->igi_ifp == ifp);
		igmp_domifreattach(IGMP_IFINFO(ifp));
	}
#endif /* INET */
	if (MLD_IFINFO(ifp) == NULL) {
		MLD_IFINFO(ifp) = mld_domifattach(ifp, Z_WAITOK);
		VERIFY(MLD_IFINFO(ifp) != NULL);
	} else {
		VERIFY(MLD_IFINFO(ifp)->mli_ifp == ifp);
		mld_domifreattach(MLD_IFINFO(ifp));
	}

	VERIFY(ifp->if_data_threshold == 0);
	VERIFY(ifp->if_dt_tcall != NULL);

	/*
	 * Wait for the created kernel threads for I/O to get
	 * scheduled and run at least once before we proceed
	 * to mark interface as attached.
	 */
	lck_mtx_lock(&ifp->if_ref_lock);
	while (ifp->if_threads_pending != 0) {
		DLIL_PRINTF("%s: Waiting for all kernel threads created for "
		    "interface %s to get scheduled at least once.\n",
		    __func__, ifp->if_xname);
		(void) msleep(&ifp->if_threads_pending, &ifp->if_ref_lock, (PZERO - 1),
		    __func__, NULL);
		LCK_MTX_ASSERT(&ifp->if_ref_lock, LCK_ASSERT_OWNED);
	}
	lck_mtx_unlock(&ifp->if_ref_lock);
	DLIL_PRINTF("%s: All kernel threads created for interface %s have been scheduled "
	    "at least once. Proceeding.\n", __func__, ifp->if_xname);

	/* Final mark this ifnet as attached. */
	ifnet_lock_exclusive(ifp);
	lck_mtx_lock_spin(&ifp->if_ref_lock);
	ifp->if_refflags = (IFRF_ATTACHED | IFRF_READY); /* clears embryonic */
	lck_mtx_unlock(&ifp->if_ref_lock);
	if (net_rtref) {
		/* boot-args override; enable idle notification */
		(void) ifnet_set_idle_flags_locked(ifp, IFRF_IDLE_NOTIFY,
		    IFRF_IDLE_NOTIFY);
	} else {
		/* apply previous request(s) to set the idle flags, if any */
		(void) ifnet_set_idle_flags_locked(ifp, ifp->if_idle_new_flags,
		    ifp->if_idle_new_flags_mask);
	}
#if SKYWALK
	/* the interface is fully attached; let the nexus adapter know */
	if (netif_compat || dlil_is_native_netif_nexus(ifp)) {
		if (netif_compat) {
			if (sk_netif_compat_txmodel ==
			    NETIF_COMPAT_TXMODEL_ENQUEUE_MULTI) {
				ifnet_enqueue_multi_setup(ifp,
				    sk_tx_delay_qlen, sk_tx_delay_timeout);
			}
			ifp->if_nx_netif = nexus_netif;
		}
		ifp->if_na_ops->ni_finalize(ifp->if_na, ifp);
	}
#endif /* SKYWALK */
	ifnet_lock_done(ifp);
	dlil_if_unlock();

#if PF
	/*
	 * Attach packet filter to this interface, if enabled.
	 */
	pf_ifnet_hook(ifp, 1);
#endif /* PF */

	dlil_post_msg(ifp, KEV_DL_SUBCLASS, KEV_DL_IF_ATTACHED, NULL, 0, FALSE);

	if (dlil_verbose) {
		DLIL_PRINTF("%s: attached%s\n", if_name(ifp),
		    (dl_if->dl_if_flags & DLIF_REUSE) ? " (recycled)" : "");
	}

	return 0;
}

static void
if_purgeaddrs(struct ifnet *ifp)
{
#if INET
	in_purgeaddrs(ifp);
#endif /* INET */
	in6_purgeaddrs(ifp);
}

errno_t
ifnet_detach(ifnet_t ifp)
{
	ifnet_ref_t delegated_ifp;
	struct nd_ifinfo *ndi = NULL;

	if (ifp == NULL) {
		return EINVAL;
	}

	ndi = ND_IFINFO(ifp);
	if (NULL != ndi) {
		ndi->cga_initialized = FALSE;
	}
	os_log(OS_LOG_DEFAULT, "%s detaching", if_name(ifp));

	/* Mark the interface down */
	if_down(ifp);

	/*
	 * IMPORTANT NOTE
	 *
	 * Any field in the ifnet that relies on IF_FULLY_ATTACHED()
	 * or equivalently, ifnet_is_attached(ifp, 1), can't be modified
	 * until after we've waited for all I/O references to drain
	 * in ifnet_detach_final().
	 */

	ifnet_head_lock_exclusive();
	ifnet_lock_exclusive(ifp);

	if (ifp->if_output_netem != NULL) {
		netem_destroy(ifp->if_output_netem);
		ifp->if_output_netem = NULL;
	}

	/*
	 * Check to see if this interface has previously triggered
	 * aggressive protocol draining; if so, decrement the global
	 * refcnt and clear PR_AGGDRAIN on the route domain if
	 * there are no more of such an interface around.
	 */
	(void) ifnet_set_idle_flags_locked(ifp, 0, ~0);

	lck_mtx_lock_spin(&ifp->if_ref_lock);
	if (!(ifp->if_refflags & IFRF_ATTACHED)) {
		lck_mtx_unlock(&ifp->if_ref_lock);
		ifnet_lock_done(ifp);
		ifnet_head_done();
		return EINVAL;
	} else if (ifp->if_refflags & IFRF_DETACHING) {
		/* Interface has already been detached */
		lck_mtx_unlock(&ifp->if_ref_lock);
		ifnet_lock_done(ifp);
		ifnet_head_done();
		return ENXIO;
	}
	VERIFY(!(ifp->if_refflags & IFRF_EMBRYONIC));
	/* Indicate this interface is being detached */
	ifp->if_refflags &= ~IFRF_ATTACHED;
	ifp->if_refflags |= IFRF_DETACHING;
	lck_mtx_unlock(&ifp->if_ref_lock);

	/* clean up flow control entry object if there's any */
	if (ifp->if_eflags & IFEF_TXSTART) {
		ifnet_flowadv(ifp->if_flowhash);
	}

	/* Reset ECN enable/disable flags */
	/* Reset CLAT46 flag */
	if_clear_eflags(ifp, IFEF_ECN_ENABLE | IFEF_ECN_DISABLE | IFEF_CLAT46);

	/*
	 * We do not reset the TCP keep alive counters in case
	 * a TCP connection stays connection after the interface
	 * went down
	 */
	if (ifp->if_tcp_kao_cnt > 0) {
		os_log(OS_LOG_DEFAULT, "%s %s tcp_kao_cnt %u not zero",
		    __func__, if_name(ifp), ifp->if_tcp_kao_cnt);
	}
	ifp->if_tcp_kao_max = 0;

	/*
	 * Remove ifnet from the ifnet_head, ifindex2ifnet[]; it will
	 * no longer be visible during lookups from this point.
	 */
	VERIFY(ifindex2ifnet[ifp->if_index] == ifp);
	TAILQ_REMOVE(&ifnet_head, ifp, if_link);
	ifp->if_link.tqe_next = NULL;
	ifp->if_link.tqe_prev = NULL;
	if (ifp->if_ordered_link.tqe_next != NULL ||
	    ifp->if_ordered_link.tqe_prev != NULL) {
		ifnet_remove_from_ordered_list(ifp);
	}
	ifindex2ifnet[ifp->if_index] = NULL;

	/* 18717626 - reset router mode */
	if_clear_eflags(ifp, IFEF_IPV4_ROUTER);
	ifp->if_ipv6_router_mode = IPV6_ROUTER_MODE_DISABLED;

	/* Record detach PC stacktrace */
	ctrace_record(&((struct dlil_ifnet *)ifp)->dl_if_detach);

	/* Clear logging parameters */
	bzero(&ifp->if_log, sizeof(ifp->if_log));

	/* Clear delegated interface info (reference released below) */
	delegated_ifp = ifp->if_delegated.ifp;
	bzero(&ifp->if_delegated, sizeof(ifp->if_delegated));

	/* Reset interface state */
	bzero(&ifp->if_interface_state, sizeof(ifp->if_interface_state));

	/*
	 * Increment the generation count on interface deletion
	 */
	ifp->if_creation_generation_id = os_atomic_inc(&if_creation_generation_count, relaxed);

	ifnet_lock_done(ifp);
	ifnet_head_done();

	/* Release reference held on the delegated interface */
	if (delegated_ifp != NULL) {
		ifnet_release(delegated_ifp);
	}

	/* Reset Link Quality Metric (unless loopback [lo0]) */
	if (ifp != lo_ifp) {
		if_lqm_update(ifp, IFNET_LQM_THRESH_OFF, 0);
	}

	/* Force reset link heuristics */
	if (ifp->if_link_heuristics_tcall != NULL) {
		thread_call_cancel_wait(ifp->if_link_heuristics_tcall);
		thread_call_free(ifp->if_link_heuristics_tcall);
		ifp->if_link_heuristics_tcall = NULL;
	}
	if_clear_xflags(ifp, IFXF_LINK_HEURISTICS);

	/* Reset TCP local statistics */
	if (ifp->if_tcp_stat != NULL) {
		bzero(ifp->if_tcp_stat, sizeof(*ifp->if_tcp_stat));
	}

	/* Reset UDP local statistics */
	if (ifp->if_udp_stat != NULL) {
		bzero(ifp->if_udp_stat, sizeof(*ifp->if_udp_stat));
	}

	/* Reset ifnet IPv4 stats */
	if (ifp->if_ipv4_stat != NULL) {
		bzero(ifp->if_ipv4_stat, sizeof(*ifp->if_ipv4_stat));
	}

	/* Reset ifnet IPv6 stats */
	if (ifp->if_ipv6_stat != NULL) {
		bzero(ifp->if_ipv6_stat, sizeof(*ifp->if_ipv6_stat));
	}

	/* Release memory held for interface link status report */
	if (ifp->if_link_status != NULL) {
		kfree_type(struct if_link_status, ifp->if_link_status);
		ifp->if_link_status = NULL;
	}

	/* Disable forwarding cached route */
	lck_mtx_lock(&ifp->if_cached_route_lock);
	ifp->if_fwd_cacheok = 0;
	lck_mtx_unlock(&ifp->if_cached_route_lock);

	/* Disable data threshold and wait for any pending event posting */
	ifp->if_data_threshold = 0;
	VERIFY(ifp->if_dt_tcall != NULL);
	(void) thread_call_cancel_wait(ifp->if_dt_tcall);

	/*
	 * Drain any deferred IGMPv3/MLDv2 query responses, but keep the
	 * references to the info structures and leave them attached to
	 * this ifnet.
	 */
#if INET
	igmp_domifdetach(ifp);
#endif /* INET */
	mld_domifdetach(ifp);

#if SKYWALK
	/* Clean up any netns tokens still pointing to to this ifnet */
	netns_ifnet_detach(ifp);
#endif /* SKYWALK */
	dlil_post_msg(ifp, KEV_DL_SUBCLASS, KEV_DL_IF_DETACHING, NULL, 0, FALSE);

	/* Let worker thread take care of the rest, to avoid reentrancy */
	dlil_if_lock();
	ifnet_detaching_enqueue(ifp);
	dlil_if_unlock();

	return 0;
}

static void
ifnet_detaching_enqueue(struct ifnet *ifp)
{
	dlil_if_lock_assert();

	++ifnet_detaching_cnt;
	VERIFY(ifnet_detaching_cnt != 0);
	TAILQ_INSERT_TAIL(&ifnet_detaching_head, ifp, if_detaching_link);
	wakeup((caddr_t)&ifnet_delayed_run);
}

static struct ifnet *
ifnet_detaching_dequeue(void)
{
	ifnet_ref_t ifp;

	dlil_if_lock_assert();

	ifp = TAILQ_FIRST(&ifnet_detaching_head);
	VERIFY(ifnet_detaching_cnt != 0 || ifp == NULL);
	if (ifp != NULL) {
		VERIFY(ifnet_detaching_cnt != 0);
		--ifnet_detaching_cnt;
		TAILQ_REMOVE(&ifnet_detaching_head, ifp, if_detaching_link);
		ifp->if_detaching_link.tqe_next = NULL;
		ifp->if_detaching_link.tqe_prev = NULL;
	}
	return ifp;
}

__attribute__((noreturn))
static void
ifnet_detacher_thread_cont(void *v, wait_result_t wres)
{
#pragma unused(v, wres)
	ifnet_ref_t ifp;

	dlil_if_lock();
	if (__improbable(ifnet_detaching_embryonic)) {
		ifnet_detaching_embryonic = FALSE;
		/* there's no lock ordering constrain so OK to do this here */
		dlil_decr_pending_thread_count();
	}

	for (;;) {
		dlil_if_lock_assert();

		if (ifnet_detaching_cnt == 0) {
			break;
		}

		net_update_uptime();

		VERIFY(TAILQ_FIRST(&ifnet_detaching_head) != NULL);

		/* Take care of detaching ifnet */
		ifp = ifnet_detaching_dequeue();
		if (ifp != NULL) {
			dlil_if_unlock();
			ifnet_detach_final(ifp);
			dlil_if_lock();
		}
	}

	(void) assert_wait(&ifnet_delayed_run, THREAD_UNINT);
	dlil_if_unlock();
	(void) thread_block(ifnet_detacher_thread_cont);

	VERIFY(0);      /* we should never get here */
	/* NOTREACHED */
	__builtin_unreachable();
}

__dead2
static void
ifnet_detacher_thread_func(void *v, wait_result_t w)
{
#pragma unused(v, w)
	dlil_if_lock();
	(void) assert_wait(&ifnet_delayed_run, THREAD_UNINT);
	ifnet_detaching_embryonic = TRUE;
	/* wake up once to get out of embryonic state */
	wakeup((caddr_t)&ifnet_delayed_run);
	dlil_if_unlock();
	(void) thread_block(ifnet_detacher_thread_cont);
	VERIFY(0);
	/* NOTREACHED */
	__builtin_unreachable();
}

static void
ifnet_detach_final(struct ifnet *ifp)
{
	struct ifnet_filter *filter, *filter_next;
	struct dlil_ifnet *dlifp;
	struct ifnet_filter_head fhead;
	struct dlil_threading_info *inp;
	struct ifaddr *ifa;
	ifnet_detached_func if_free;
	int i;
	bool waited = false;

	/* Let BPF know we're detaching */
	bpfdetach(ifp);

#if SKYWALK
	dlil_netif_detach_notify(ifp);
	/*
	 * Wait for the datapath to quiesce before tearing down
	 * netif/flowswitch nexuses.
	 */
	dlil_quiesce_and_detach_nexuses(ifp);
#endif /* SKYWALK */

	lck_mtx_lock(&ifp->if_ref_lock);
	if (!(ifp->if_refflags & IFRF_DETACHING)) {
		panic("%s: flags mismatch (detaching not set) ifp=%p",
		    __func__, ifp);
		/* NOTREACHED */
	}

	/*
	 * Wait until the existing IO references get released
	 * before we proceed with ifnet_detach.  This is not a
	 * common case, so block without using a continuation.
	 */
	while (ifp->if_refio > 0) {
		waited = true;
		DLIL_PRINTF("%s: %s waiting for IO references to drain\n",
		    __func__, if_name(ifp));
		(void) msleep(&(ifp->if_refio), &ifp->if_ref_lock,
		    (PZERO - 1), "ifnet_ioref_wait", NULL);
	}
	if (waited) {
		DLIL_PRINTF("%s: %s IO references drained\n",
		    __func__, if_name(ifp));
	}
	VERIFY(ifp->if_datamov == 0);
	VERIFY(ifp->if_drainers == 0);
	VERIFY(ifp->if_suspend == 0);
	ifp->if_refflags &= ~IFRF_READY;
	lck_mtx_unlock(&ifp->if_ref_lock);

#if SKYWALK
	VERIFY(LIST_EMPTY(&ifp->if_netns_tokens));
#endif /* SKYWALK */
	/* Drain and destroy send queue */
	ifclassq_teardown(ifp->if_snd);

	/* Detach interface filters */
	lck_mtx_lock(&ifp->if_flt_lock);
	if_flt_monitor_enter(ifp);

	LCK_MTX_ASSERT(&ifp->if_flt_lock, LCK_MTX_ASSERT_OWNED);
	fhead = ifp->if_flt_head;
	TAILQ_INIT(&ifp->if_flt_head);

	for (filter = TAILQ_FIRST(&fhead); filter; filter = filter_next) {
		filter_next = TAILQ_NEXT(filter, filt_next);
		lck_mtx_unlock(&ifp->if_flt_lock);

		dlil_detach_filter_internal(filter, 1);
		lck_mtx_lock(&ifp->if_flt_lock);
	}
	if_flt_monitor_leave(ifp);
	lck_mtx_unlock(&ifp->if_flt_lock);

	/* Tell upper layers to drop their network addresses */
	if_purgeaddrs(ifp);

	ifnet_lock_exclusive(ifp);

	/* Clear agent IDs */
	if (ifp->if_agentids != NULL) {
		kfree_data_sized_by(ifp->if_agentids, ifp->if_agentcount);
	}

	bzero(&ifp->if_nx_netif, sizeof(ifp->if_nx_netif));
	bzero(&ifp->if_nx_flowswitch, sizeof(ifp->if_nx_flowswitch));

	/* Unplumb all protocols */
	for (i = 0; i < PROTO_HASH_SLOTS; i++) {
		struct if_proto *proto;

		proto = SLIST_FIRST(&ifp->if_proto_hash[i]);
		while (proto != NULL) {
			protocol_family_t family = proto->protocol_family;
			ifnet_lock_done(ifp);
			proto_unplumb(family, ifp);
			ifnet_lock_exclusive(ifp);
			proto = SLIST_FIRST(&ifp->if_proto_hash[i]);
		}
		/* There should not be any protocols left */
		VERIFY(SLIST_EMPTY(&ifp->if_proto_hash[i]));
	}
	kfree_type_counted_by(struct proto_hash_entry, ifp->if_proto_hash_count, ifp->if_proto_hash);

	/* Detach (permanent) link address from if_addrhead */
	ifa = TAILQ_FIRST(&ifp->if_addrhead);
	VERIFY(ifnet_addrs[ifp->if_index - 1] == ifa);
	IFA_LOCK(ifa);
	if_detach_link_ifa(ifp, ifa);
	IFA_UNLOCK(ifa);

	/* Remove (permanent) link address from ifnet_addrs[] */
	ifa_remref(ifa);
	ifnet_addrs[ifp->if_index - 1] = NULL;

	/* This interface should not be on {ifnet_head,detaching} */
	VERIFY(ifp->if_link.tqe_next == NULL);
	VERIFY(ifp->if_link.tqe_prev == NULL);
	VERIFY(ifp->if_detaching_link.tqe_next == NULL);
	VERIFY(ifp->if_detaching_link.tqe_prev == NULL);
	VERIFY(ifp->if_ordered_link.tqe_next == NULL);
	VERIFY(ifp->if_ordered_link.tqe_prev == NULL);

	/* The slot should have been emptied */
	VERIFY(ifindex2ifnet[ifp->if_index] == NULL);

	/* There should not be any addresses left */
	VERIFY(TAILQ_EMPTY(&ifp->if_addrhead));

	/*
	 * Signal the starter thread to terminate itself, and wait until
	 * it has exited.
	 */
	if (ifp->if_start_thread != THREAD_NULL) {
		lck_mtx_lock_spin(&ifp->if_start_lock);
		ifp->if_start_flags |= IFSF_TERMINATING;
		wakeup_one((caddr_t)&ifp->if_start_thread);
		lck_mtx_unlock(&ifp->if_start_lock);

		/* wait for starter thread to terminate */
		lck_mtx_lock(&ifp->if_start_lock);
		while (ifp->if_start_thread != THREAD_NULL) {
			if (dlil_verbose) {
				DLIL_PRINTF("%s: waiting for %s starter thread to terminate\n",
				    __func__,
				    if_name(ifp));
			}
			(void) msleep(&ifp->if_start_thread,
			    &ifp->if_start_lock, (PZERO - 1),
			    "ifnet_start_thread_exit", NULL);
		}
		lck_mtx_unlock(&ifp->if_start_lock);
		if (dlil_verbose) {
			DLIL_PRINTF("%s: %s starter thread termination complete",
			    __func__, if_name(ifp));
		}
	}

	/*
	 * Signal the poller thread to terminate itself, and wait until
	 * it has exited.
	 */
	if (ifp->if_poll_thread != THREAD_NULL) {
#if SKYWALK
		VERIFY(!(ifp->if_eflags & IFEF_SKYWALK_NATIVE));
#endif /* SKYWALK */
		lck_mtx_lock_spin(&ifp->if_poll_lock);
		ifp->if_poll_flags |= IF_POLLF_TERMINATING;
		wakeup_one((caddr_t)&ifp->if_poll_thread);
		lck_mtx_unlock(&ifp->if_poll_lock);

		/* wait for poller thread to terminate */
		lck_mtx_lock(&ifp->if_poll_lock);
		while (ifp->if_poll_thread != THREAD_NULL) {
			if (dlil_verbose) {
				DLIL_PRINTF("%s: waiting for %s poller thread to terminate\n",
				    __func__,
				    if_name(ifp));
			}
			(void) msleep(&ifp->if_poll_thread,
			    &ifp->if_poll_lock, (PZERO - 1),
			    "ifnet_poll_thread_exit", NULL);
		}
		lck_mtx_unlock(&ifp->if_poll_lock);
		if (dlil_verbose) {
			DLIL_PRINTF("%s: %s poller thread termination complete\n",
			    __func__, if_name(ifp));
		}
	}

	/*
	 * If thread affinity was set for the workloop thread, we will need
	 * to tear down the affinity and release the extra reference count
	 * taken at attach time.  Does not apply to lo0 or other interfaces
	 * without dedicated input threads.
	 */
	if ((inp = ifp->if_inp) != NULL) {
		VERIFY(inp != dlil_main_input_thread);

		if (inp->dlth_affinity) {
			struct thread *__single tp, *__single wtp, *__single ptp;

			lck_mtx_lock_spin(&inp->dlth_lock);
			wtp = inp->dlth_driver_thread;
			inp->dlth_driver_thread = THREAD_NULL;
			ptp = inp->dlth_poller_thread;
			inp->dlth_poller_thread = THREAD_NULL;
			ASSERT(inp->dlth_thread != THREAD_NULL);
			tp = inp->dlth_thread;    /* don't nullify now */
			inp->dlth_affinity_tag = 0;
			inp->dlth_affinity = FALSE;
			lck_mtx_unlock(&inp->dlth_lock);

			/* Tear down poll thread affinity */
			if (ptp != NULL) {
				VERIFY(ifp->if_eflags & IFEF_RXPOLL);
				VERIFY(ifp->if_xflags & IFXF_LEGACY);
				(void) dlil_affinity_set(ptp,
				    THREAD_AFFINITY_TAG_NULL);
				thread_deallocate(ptp);
			}

			/* Tear down workloop thread affinity */
			if (wtp != NULL) {
				(void) dlil_affinity_set(wtp,
				    THREAD_AFFINITY_TAG_NULL);
				thread_deallocate(wtp);
			}

			/* Tear down DLIL input thread affinity */
			(void) dlil_affinity_set(tp, THREAD_AFFINITY_TAG_NULL);
			thread_deallocate(tp);
		}

		/* disassociate ifp DLIL input thread */
		ifp->if_inp = NULL;

		/* if the worker thread was created, tell it to terminate */
		if (inp->dlth_thread != THREAD_NULL) {
			lck_mtx_lock_spin(&inp->dlth_lock);
			inp->dlth_flags |= DLIL_INPUT_TERMINATE;
			if (!(inp->dlth_flags & DLIL_INPUT_RUNNING)) {
				wakeup_one((caddr_t)&inp->dlth_flags);
			}
			lck_mtx_unlock(&inp->dlth_lock);
			ifnet_lock_done(ifp);

			/* wait for the input thread to terminate */
			lck_mtx_lock_spin(&inp->dlth_lock);
			while ((inp->dlth_flags & DLIL_INPUT_TERMINATE_COMPLETE)
			    == 0) {
				(void) msleep(&inp->dlth_flags, &inp->dlth_lock,
				    (PZERO - 1) | PSPIN, inp->dlth_name, NULL);
			}
			lck_mtx_unlock(&inp->dlth_lock);
			ifnet_lock_exclusive(ifp);
		}

		/* clean-up input thread state */
		dlil_clean_threading_info(inp);
		/* clean-up poll parameters */
		VERIFY(ifp->if_poll_thread == THREAD_NULL);
		dlil_reset_rxpoll_params(ifp);
	}

	/* The driver might unload, so point these to ourselves */
	if_free = ifp->if_free;
	ifp->if_output_dlil = ifp_if_output;
	ifp->if_output = ifp_if_output;
	ifp->if_pre_enqueue = ifp_if_output;
	ifp->if_start = ifp_if_start;
	ifp->if_output_ctl = ifp_if_ctl;
	ifp->if_input_dlil = ifp_if_input;
	ifp->if_input_poll = ifp_if_input_poll;
	ifp->if_input_ctl = ifp_if_ctl;
	ifp->if_ioctl = ifp_if_ioctl;
	ifp->if_set_bpf_tap = ifp_if_set_bpf_tap;
	ifp->if_free = ifp_if_free;
	ifp->if_demux = ifp_if_demux;
	ifp->if_event = ifp_if_event;
	ifp->if_framer_legacy = ifp_if_framer;
	ifp->if_framer = ifp_if_framer_extended;
	ifp->if_add_proto = ifp_if_add_proto;
	ifp->if_del_proto = ifp_if_del_proto;
	ifp->if_check_multi = ifp_if_check_multi;

	/* wipe out interface description */
	VERIFY(ifp->if_desc.ifd_maxlen == IF_DESCSIZE);
	ifp->if_desc.ifd_len = 0;
	VERIFY(ifp->if_desc.ifd_desc != NULL);
	bzero(ifp->if_desc.ifd_desc, IF_DESCSIZE);

	/* there shouldn't be any delegation by now */
	VERIFY(ifp->if_delegated.ifp == NULL);
	VERIFY(ifp->if_delegated.type == 0);
	VERIFY(ifp->if_delegated.family == 0);
	VERIFY(ifp->if_delegated.subfamily == 0);
	VERIFY(ifp->if_delegated.expensive == 0);
	VERIFY(ifp->if_delegated.constrained == 0);
	VERIFY(ifp->if_delegated.ultra_constrained == 0);

	/* QoS marking get cleared */
	if_clear_eflags(ifp, IFEF_QOSMARKING_ENABLED);
	if_set_qosmarking_mode(ifp, IFRTYPE_QOSMARKING_MODE_NONE);

#if SKYWALK
	/* the nexus destructor is responsible for clearing these */
	VERIFY(ifp->if_na_ops == NULL);
	VERIFY(ifp->if_na == NULL);
#endif /* SKYWALK */

	/* interface could come up with different hwassist next time */
	ifp->if_hwassist = 0;
	ifp->if_capenable = 0;

	/* promiscuous/allmulti counts need to start at zero again */
	ifp->if_pcount = 0;
	ifp->if_amcount = 0;
	ifp->if_flags &= ~(IFF_PROMISC | IFF_ALLMULTI);

	ifnet_lock_done(ifp);

#if PF
	/*
	 * Detach this interface from packet filter, if enabled.
	 */
	pf_ifnet_hook(ifp, 0);
#endif /* PF */

	/* Filter list should be empty */
	lck_mtx_lock_spin(&ifp->if_flt_lock);
	VERIFY(TAILQ_EMPTY(&ifp->if_flt_head));
	VERIFY(ifp->if_flt_busy == 0);
	VERIFY(ifp->if_flt_waiters == 0);
	VERIFY(ifp->if_flt_non_os_count == 0);
	VERIFY(ifp->if_flt_no_tso_count == 0);
	lck_mtx_unlock(&ifp->if_flt_lock);

	/* Last chance to drain send queue */
	if_qflush_snd(ifp, 0);

	/* Last chance to cleanup any cached route */
	lck_mtx_lock(&ifp->if_cached_route_lock);
	VERIFY(!ifp->if_fwd_cacheok);
	ROUTE_RELEASE(&ifp->if_fwd_route);
	bzero(&ifp->if_fwd_route, sizeof(ifp->if_fwd_route));
	ROUTE_RELEASE(&ifp->if_src_route);
	bzero(&ifp->if_src_route, sizeof(ifp->if_src_route));
	ROUTE_RELEASE(&ifp->if_src_route6);
	bzero(&ifp->if_src_route6, sizeof(ifp->if_src_route6));
	lck_mtx_unlock(&ifp->if_cached_route_lock);

	/* Ignore any pending data threshold as the interface is anyways gone */
	ifp->if_data_threshold = 0;

	VERIFY(ifp->if_dt_tcall != NULL);
	VERIFY(!thread_call_isactive(ifp->if_dt_tcall));

	ifnet_llreach_ifdetach(ifp);

	dlil_post_msg(ifp, KEV_DL_SUBCLASS, KEV_DL_IF_DETACHED, NULL, 0, FALSE);

	/*
	 * Finally, mark this ifnet as detached.
	 */
	os_log(OS_LOG_DEFAULT, "%s detached", if_name(ifp));

	lck_mtx_lock_spin(&ifp->if_ref_lock);
	if (!(ifp->if_refflags & IFRF_DETACHING)) {
		panic("%s: flags mismatch (detaching not set) ifp=%p",
		    __func__, ifp);
		/* NOTREACHED */
	}
	ifp->if_refflags &= ~IFRF_DETACHING;
	lck_mtx_unlock(&ifp->if_ref_lock);
	if (if_free != NULL) {
		if_free(ifp);
	}

	ifclassq_release(&ifp->if_snd);

	/* we're fully detached, clear the "in use" bit */
	dlifp = (struct dlil_ifnet *)ifp;
	lck_mtx_lock(&dlifp->dl_if_lock);
	ASSERT((dlifp->dl_if_flags & DLIF_INUSE) != 0);
	dlifp->dl_if_flags &= ~DLIF_INUSE;
	lck_mtx_unlock(&dlifp->dl_if_lock);

	/* Release reference held during ifnet attach */
	ifnet_release(ifp);
}

errno_t
ifp_if_output(struct ifnet *ifp, struct mbuf *m)
{
#pragma unused(ifp)
	m_freem_list(m);
	return 0;
}

void
ifp_if_start(struct ifnet *ifp)
{
	ifnet_purge(ifp);
}

static errno_t
ifp_if_input(struct ifnet *ifp, struct mbuf *m_head,
    struct mbuf *m_tail, const struct ifnet_stat_increment_param *s,
    boolean_t poll, struct thread *tp)
{
#pragma unused(ifp, m_tail, s, poll, tp)
	m_freem_list(m_head);
	return ENXIO;
}

static void
ifp_if_input_poll(struct ifnet *ifp, u_int32_t flags, u_int32_t max_cnt,
    struct mbuf **m_head, struct mbuf **m_tail, u_int32_t *cnt, u_int32_t *len)
{
#pragma unused(ifp, flags, max_cnt)
	if (m_head != NULL) {
		*m_head = NULL;
	}
	if (m_tail != NULL) {
		*m_tail = NULL;
	}
	if (cnt != NULL) {
		*cnt = 0;
	}
	if (len != NULL) {
		*len = 0;
	}
}

static errno_t
ifp_if_ctl(struct ifnet *ifp, ifnet_ctl_cmd_t cmd, u_int32_t arglen, void *arg)
{
#pragma unused(ifp, cmd, arglen, arg)
	return EOPNOTSUPP;
}

static errno_t
ifp_if_demux(struct ifnet *ifp, struct mbuf *m, char *fh, protocol_family_t *pf)
{
#pragma unused(ifp, fh, pf)
	m_freem(m);
	return EJUSTRETURN;
}

static errno_t
ifp_if_add_proto(struct ifnet *ifp, protocol_family_t pf,
    const struct ifnet_demux_desc *da, u_int32_t dc)
{
#pragma unused(ifp, pf, da, dc)
	return EINVAL;
}

static errno_t
ifp_if_del_proto(struct ifnet *ifp, protocol_family_t pf)
{
#pragma unused(ifp, pf)
	return EINVAL;
}

static errno_t
ifp_if_check_multi(struct ifnet *ifp, const struct sockaddr *sa)
{
#pragma unused(ifp, sa)
	return EOPNOTSUPP;
}

#if !XNU_TARGET_OS_OSX
static errno_t
ifp_if_framer(struct ifnet *ifp, struct mbuf **m,
    const struct sockaddr *sa, IFNET_LLADDR_T ll, IFNET_FRAME_TYPE_T t,
    u_int32_t *pre, u_int32_t *post)
#else /* XNU_TARGET_OS_OSX */
static errno_t
ifp_if_framer(struct ifnet *ifp, struct mbuf **m,
    const struct sockaddr *sa, IFNET_LLADDR_T ll, IFNET_FRAME_TYPE_T t)
#endif /* XNU_TARGET_OS_OSX */
{
#pragma unused(ifp, m, sa, ll, t)
#if !XNU_TARGET_OS_OSX
	return ifp_if_framer_extended(ifp, m, sa, ll, t, pre, post);
#else /* XNU_TARGET_OS_OSX */
	return ifp_if_framer_extended(ifp, m, sa, ll, t, NULL, NULL);
#endif /* XNU_TARGET_OS_OSX */
}

static errno_t
ifp_if_framer_extended(struct ifnet *ifp, struct mbuf **m,
    const struct sockaddr *sa,
    IFNET_LLADDR_T ll,
    IFNET_FRAME_TYPE_T t,
    u_int32_t *pre, u_int32_t *post)
{
#pragma unused(ifp, sa, ll, t)
	m_freem(*m);
	*m = NULL;

	if (pre != NULL) {
		*pre = 0;
	}
	if (post != NULL) {
		*post = 0;
	}

	return EJUSTRETURN;
}

errno_t
ifp_if_ioctl(struct ifnet *ifp, unsigned long cmd, void *arg)
{
#pragma unused(ifp, cmd, arg)
	return EOPNOTSUPP;
}

static errno_t
ifp_if_set_bpf_tap(struct ifnet *ifp, bpf_tap_mode tm, bpf_packet_func f)
{
#pragma unused(ifp, tm, f)
	/* XXX not sure what to do here */
	return 0;
}

static void
ifp_if_free(struct ifnet *ifp)
{
#pragma unused(ifp)
}

static void
ifp_if_event(struct ifnet *ifp, const struct kev_msg *e)
{
#pragma unused(ifp, e)
}

__private_extern__ void
dlil_proto_unplumb_all(struct ifnet *ifp)
{
	/*
	 * if_proto_hash[0-2] are for PF_INET, PF_INET6 and PF_VLAN, where
	 * each bucket contains exactly one entry; PF_VLAN does not need an
	 * explicit unplumb.
	 *
	 * if_proto_hash[3] is for other protocols; we expect anything
	 * in this bucket to respond to the DETACHING event (which would
	 * have happened by now) and do the unplumb then.
	 */
	(void) proto_unplumb(PF_INET, ifp);
	(void) proto_unplumb(PF_INET6, ifp);
}

static void
ifp_src_route_copyout(struct ifnet *ifp, struct route *dst)
{
	lck_mtx_lock_spin(&ifp->if_cached_route_lock);
	lck_mtx_convert_spin(&ifp->if_cached_route_lock);

	route_copyout(dst, &ifp->if_src_route, sizeof(*dst));

	lck_mtx_unlock(&ifp->if_cached_route_lock);
}

static void
ifp_src_route_copyin(struct ifnet *ifp, struct route *src)
{
	lck_mtx_lock_spin(&ifp->if_cached_route_lock);
	lck_mtx_convert_spin(&ifp->if_cached_route_lock);

	if (ifp->if_fwd_cacheok) {
		route_copyin(src, &ifp->if_src_route, sizeof(*src));
	} else {
		ROUTE_RELEASE(src);
	}
	lck_mtx_unlock(&ifp->if_cached_route_lock);
}

static void
ifp_src_route6_copyout(struct ifnet *ifp, struct route_in6 *dst)
{
	lck_mtx_lock_spin(&ifp->if_cached_route_lock);
	lck_mtx_convert_spin(&ifp->if_cached_route_lock);

	route_copyout((struct route *)dst, (struct route *)&ifp->if_src_route6,
	    sizeof(*dst));

	lck_mtx_unlock(&ifp->if_cached_route_lock);
}

static void
ifp_src_route6_copyin(struct ifnet *ifp, struct route_in6 *src)
{
	lck_mtx_lock_spin(&ifp->if_cached_route_lock);
	lck_mtx_convert_spin(&ifp->if_cached_route_lock);

	if (ifp->if_fwd_cacheok) {
		route_copyin((struct route *)src,
		    (struct route *)&ifp->if_src_route6, sizeof(*src));
	} else {
		ROUTE_RELEASE(src);
	}
	lck_mtx_unlock(&ifp->if_cached_route_lock);
}

struct rtentry *
ifnet_cached_rtlookup_inet(struct ifnet *ifp, struct in_addr src_ip)
{
	struct route            src_rt;
	struct sockaddr_in      *dst;

	dst = SIN(&src_rt.ro_dst);

	ifp_src_route_copyout(ifp, &src_rt);

	if (ROUTE_UNUSABLE(&src_rt) || src_ip.s_addr != dst->sin_addr.s_addr) {
		ROUTE_RELEASE(&src_rt);
		if (dst->sin_family != AF_INET) {
			SOCKADDR_ZERO(&src_rt.ro_dst, sizeof(src_rt.ro_dst));
			dst->sin_len = sizeof(src_rt.ro_dst);
			dst->sin_family = AF_INET;
		}
		dst->sin_addr = src_ip;

		VERIFY(src_rt.ro_rt == NULL);
		src_rt.ro_rt = rtalloc1_scoped(SA(dst),
		    0, 0, ifp->if_index);

		if (src_rt.ro_rt != NULL) {
			/* retain a ref, copyin consumes one */
			struct rtentry  *rte = src_rt.ro_rt;
			RT_ADDREF(rte);
			ifp_src_route_copyin(ifp, &src_rt);
			src_rt.ro_rt = rte;
		}
	}

	return src_rt.ro_rt;
}

struct rtentry *
ifnet_cached_rtlookup_inet6(struct ifnet *ifp, struct in6_addr *src_ip6)
{
	struct route_in6 src_rt;

	ifp_src_route6_copyout(ifp, &src_rt);

	if (ROUTE_UNUSABLE(&src_rt) ||
	    !IN6_ARE_ADDR_EQUAL(src_ip6, &src_rt.ro_dst.sin6_addr)) {
		ROUTE_RELEASE(&src_rt);
		if (src_rt.ro_dst.sin6_family != AF_INET6) {
			SOCKADDR_ZERO(&src_rt.ro_dst, sizeof(src_rt.ro_dst));
			src_rt.ro_dst.sin6_len = sizeof(src_rt.ro_dst);
			src_rt.ro_dst.sin6_family = AF_INET6;
		}
		src_rt.ro_dst.sin6_scope_id = in6_addr2scopeid(ifp, src_ip6);
		bcopy(src_ip6, &src_rt.ro_dst.sin6_addr,
		    sizeof(src_rt.ro_dst.sin6_addr));

		if (src_rt.ro_rt == NULL) {
			src_rt.ro_rt = rtalloc1_scoped(
				SA(&src_rt.ro_dst), 0, 0,
				ifp->if_index);

			if (src_rt.ro_rt != NULL) {
				/* retain a ref, copyin consumes one */
				struct rtentry  *rte = src_rt.ro_rt;
				RT_ADDREF(rte);
				ifp_src_route6_copyin(ifp, &src_rt);
				src_rt.ro_rt = rte;
			}
		}
	}

	return src_rt.ro_rt;
}

void
if_lqm_update(struct ifnet *ifp, int lqm, int locked)
{
	struct kev_dl_link_quality_metric_data ev_lqm_data;
	uint64_t now, delta;
	int8_t old_lqm;
	bool need_necp_client_update;

	VERIFY(lqm >= IFNET_LQM_MIN && lqm <= IFNET_LQM_MAX);

	/* Normalize to edge */
	if (lqm >= 0 && lqm <= IFNET_LQM_THRESH_ABORT) {
		lqm = IFNET_LQM_THRESH_ABORT;
		os_atomic_or(&tcbinfo.ipi_flags, INPCBINFO_HANDLE_LQM_ABORT, relaxed);
		inpcb_timer_sched(&tcbinfo, INPCB_TIMER_FAST);
	} else if (lqm > IFNET_LQM_THRESH_ABORT &&
	    lqm <= IFNET_LQM_THRESH_MINIMALLY_VIABLE) {
		lqm = IFNET_LQM_THRESH_MINIMALLY_VIABLE;
	} else if (lqm > IFNET_LQM_THRESH_MINIMALLY_VIABLE &&
	    lqm <= IFNET_LQM_THRESH_POOR) {
		lqm = IFNET_LQM_THRESH_POOR;
	} else if (lqm > IFNET_LQM_THRESH_POOR &&
	    lqm <= IFNET_LQM_THRESH_GOOD) {
		lqm = IFNET_LQM_THRESH_GOOD;
	}

	/*
	 * Take the lock if needed
	 */
	if (!locked) {
		ifnet_lock_exclusive(ifp);
	}

	if (lqm == ifp->if_interface_state.lqm_state &&
	    (ifp->if_interface_state.valid_bitmask &
	    IF_INTERFACE_STATE_LQM_STATE_VALID)) {
		/*
		 * Release the lock if was not held by the caller
		 */
		if (!locked) {
			ifnet_lock_done(ifp);
		}
		return;         /* nothing to update */
	}

	net_update_uptime();
	now = net_uptime_ms();
	ASSERT(now >= ifp->if_lqmstate_start_time);
	delta = now - ifp->if_lqmstate_start_time;

	old_lqm = ifp->if_interface_state.lqm_state;
	switch (old_lqm) {
	case IFNET_LQM_THRESH_GOOD:
		ifp->if_lqm_good_time += delta;
		break;
	case IFNET_LQM_THRESH_POOR:
		ifp->if_lqm_poor_time += delta;
		break;
	case IFNET_LQM_THRESH_MINIMALLY_VIABLE:
		ifp->if_lqm_min_viable_time += delta;
		break;
	case IFNET_LQM_THRESH_BAD:
		ifp->if_lqm_bad_time += delta;
		break;
	default:
		break;
	}
	switch (lqm) {
	case IFNET_LQM_THRESH_GOOD:
		ifp->if_lqm_good_cnt += 1;
		break;
	case IFNET_LQM_THRESH_POOR:
		ifp->if_lqm_poor_cnt += 1;
		break;
	case IFNET_LQM_THRESH_MINIMALLY_VIABLE:
		ifp->if_lqm_min_viable_cnt += 1;
		break;
	case IFNET_LQM_THRESH_BAD:
		ifp->if_lqm_bad_cnt += 1;
		break;
	default:
		break;
	}
	ifp->if_lqmstate_start_time = now;

	ifp->if_interface_state.valid_bitmask |=
	    IF_INTERFACE_STATE_LQM_STATE_VALID;
	ifp->if_interface_state.lqm_state = (int8_t)lqm;

	/*
	 * Update the link heuristics
	 */
	need_necp_client_update = if_update_link_heuristic(ifp);

	/*
	 * Don't want to hold the lock when issuing kernel events or calling NECP
	 */
	ifnet_lock_done(ifp);

	if (need_necp_client_update) {
		necp_update_all_clients_immediately_if_needed(true);
	}

	bzero(&ev_lqm_data, sizeof(ev_lqm_data));
	ev_lqm_data.link_quality_metric = lqm;

	dlil_post_msg(ifp, KEV_DL_SUBCLASS, KEV_DL_LINK_QUALITY_METRIC_CHANGED,
	    (struct net_event_data *)&ev_lqm_data, sizeof(ev_lqm_data), FALSE);

	/*
	 * Reacquire the lock for the caller
	 */
	if (locked) {
		ifnet_lock_exclusive(ifp);
	}
}

static void
if_rrc_state_update(struct ifnet *ifp, unsigned int rrc_state)
{
	struct kev_dl_rrc_state kev;

	if (rrc_state == ifp->if_interface_state.rrc_state &&
	    (ifp->if_interface_state.valid_bitmask &
	    IF_INTERFACE_STATE_RRC_STATE_VALID)) {
		return;
	}

	ifp->if_interface_state.valid_bitmask |=
	    IF_INTERFACE_STATE_RRC_STATE_VALID;

	ifp->if_interface_state.rrc_state = (uint8_t)rrc_state;

	/*
	 * Don't want to hold the lock when issuing kernel events
	 */
	ifnet_lock_done(ifp);

	bzero(&kev, sizeof(struct kev_dl_rrc_state));
	kev.rrc_state = rrc_state;

	dlil_post_msg(ifp, KEV_DL_SUBCLASS, KEV_DL_RRC_STATE_CHANGED,
	    (struct net_event_data *)&kev, sizeof(struct kev_dl_rrc_state), FALSE);

	ifnet_lock_exclusive(ifp);
}

errno_t
if_state_update(struct ifnet *ifp,
    struct if_interface_state *if_interface_state)
{
	u_short if_index_available = 0;

	ifnet_lock_exclusive(ifp);

	if ((ifp->if_type != IFT_CELLULAR) &&
	    (if_interface_state->valid_bitmask &
	    IF_INTERFACE_STATE_RRC_STATE_VALID)) {
		ifnet_lock_done(ifp);
		return ENOTSUP;
	}
	if ((if_interface_state->valid_bitmask &
	    IF_INTERFACE_STATE_LQM_STATE_VALID) &&
	    (if_interface_state->lqm_state < IFNET_LQM_MIN ||
	    if_interface_state->lqm_state > IFNET_LQM_MAX)) {
		ifnet_lock_done(ifp);
		return EINVAL;
	}
	if ((if_interface_state->valid_bitmask &
	    IF_INTERFACE_STATE_RRC_STATE_VALID) &&
	    if_interface_state->rrc_state !=
	    IF_INTERFACE_STATE_RRC_STATE_IDLE &&
	    if_interface_state->rrc_state !=
	    IF_INTERFACE_STATE_RRC_STATE_CONNECTED) {
		ifnet_lock_done(ifp);
		return EINVAL;
	}

	if (if_interface_state->valid_bitmask &
	    IF_INTERFACE_STATE_LQM_STATE_VALID) {
		if_lqm_update(ifp, if_interface_state->lqm_state, 1);
	}
	if (if_interface_state->valid_bitmask &
	    IF_INTERFACE_STATE_RRC_STATE_VALID) {
		if_rrc_state_update(ifp, if_interface_state->rrc_state);
	}
	if (if_interface_state->valid_bitmask &
	    IF_INTERFACE_STATE_INTERFACE_AVAILABILITY_VALID) {
		ifp->if_interface_state.valid_bitmask |=
		    IF_INTERFACE_STATE_INTERFACE_AVAILABILITY_VALID;
		ifp->if_interface_state.interface_availability =
		    if_interface_state->interface_availability;

		if (ifp->if_interface_state.interface_availability ==
		    IF_INTERFACE_STATE_INTERFACE_AVAILABLE) {
			os_log(OS_LOG_DEFAULT, "%s: interface %s (%u) available\n",
			    __func__, if_name(ifp), ifp->if_index);
			if_index_available = ifp->if_index;
		} else {
			os_log(OS_LOG_DEFAULT, "%s: interface %s (%u) unavailable)\n",
			    __func__, if_name(ifp), ifp->if_index);
		}
	}
	ifnet_lock_done(ifp);

	/*
	 * Check if the TCP connections going on this interface should be
	 * forced to send probe packets instead of waiting for TCP timers
	 * to fire. This is done on an explicit notification such as
	 * SIOCSIFINTERFACESTATE which marks the interface as available.
	 */
	if (if_index_available > 0) {
		tcp_interface_send_probe(if_index_available);
	}

	return 0;
}

void
if_get_state(struct ifnet *ifp,
    struct if_interface_state *if_interface_state)
{
	ifnet_lock_shared(ifp);

	if_interface_state->valid_bitmask = 0;

	if (ifp->if_interface_state.valid_bitmask &
	    IF_INTERFACE_STATE_RRC_STATE_VALID) {
		if_interface_state->valid_bitmask |=
		    IF_INTERFACE_STATE_RRC_STATE_VALID;
		if_interface_state->rrc_state =
		    ifp->if_interface_state.rrc_state;
	}
	if (ifp->if_interface_state.valid_bitmask &
	    IF_INTERFACE_STATE_LQM_STATE_VALID) {
		if_interface_state->valid_bitmask |=
		    IF_INTERFACE_STATE_LQM_STATE_VALID;
		if_interface_state->lqm_state =
		    ifp->if_interface_state.lqm_state;
	}
	if (ifp->if_interface_state.valid_bitmask &
	    IF_INTERFACE_STATE_INTERFACE_AVAILABILITY_VALID) {
		if_interface_state->valid_bitmask |=
		    IF_INTERFACE_STATE_INTERFACE_AVAILABILITY_VALID;
		if_interface_state->interface_availability =
		    ifp->if_interface_state.interface_availability;
	}

	ifnet_lock_done(ifp);
}

errno_t
if_probe_connectivity(struct ifnet *ifp, u_int32_t conn_probe)
{
	if (conn_probe > 1) {
		return EINVAL;
	}
	if (conn_probe == 0) {
		if_clear_eflags(ifp, IFEF_PROBE_CONNECTIVITY);
	} else {
		if_set_eflags(ifp, IFEF_PROBE_CONNECTIVITY);
	}

#if NECP
	necp_update_all_clients();
#endif /* NECP */

	tcp_probe_connectivity(ifp, conn_probe);
	return 0;
}

/* for uuid.c */
static int
get_ether_index(int * ret_other_index)
{
	ifnet_ref_t ifp;
	int en0_index = 0;
	int other_en_index = 0;
	int any_ether_index = 0;
	short best_unit = 0;

	*ret_other_index = 0;
	TAILQ_FOREACH(ifp, &ifnet_head, if_link) {
		/*
		 * find en0, or if not en0, the lowest unit en*, and if not
		 * that, any ethernet
		 */
		ifnet_lock_shared(ifp);
		if (strcmp(ifp->if_name, "en") == 0) {
			if (ifp->if_unit == 0) {
				/* found en0, we're done */
				en0_index = ifp->if_index;
				ifnet_lock_done(ifp);
				break;
			}
			if (other_en_index == 0 || ifp->if_unit < best_unit) {
				other_en_index = ifp->if_index;
				best_unit = ifp->if_unit;
			}
		} else if (ifp->if_type == IFT_ETHER && any_ether_index == 0) {
			any_ether_index = ifp->if_index;
		}
		ifnet_lock_done(ifp);
	}
	if (en0_index == 0) {
		if (other_en_index != 0) {
			*ret_other_index = other_en_index;
		} else if (any_ether_index != 0) {
			*ret_other_index = any_ether_index;
		}
	}
	return en0_index;
}

int
uuid_get_ethernet(u_int8_t *__counted_by(ETHER_ADDR_LEN) node)
{
	static int en0_index;
	ifnet_ref_t ifp;
	int other_index = 0;
	int the_index = 0;
	int ret;

	ifnet_head_lock_shared();
	if (en0_index == 0 || ifindex2ifnet[en0_index] == NULL) {
		en0_index = get_ether_index(&other_index);
	}
	if (en0_index != 0) {
		the_index = en0_index;
	} else if (other_index != 0) {
		the_index = other_index;
	}
	if (the_index != 0) {
		struct dlil_ifnet *dl_if;

		ifp = ifindex2ifnet[the_index];
		VERIFY(ifp != NULL);
		dl_if = (struct dlil_ifnet *)ifp;
		if (dl_if->dl_if_permanent_ether_is_set != 0) {
			/*
			 * Use the permanent ethernet address if it is
			 * available because it will never change.
			 */
			memcpy(node, dl_if->dl_if_permanent_ether,
			    ETHER_ADDR_LEN);
		} else {
			memcpy(node, IF_LLADDR(ifp), ETHER_ADDR_LEN);
		}
		ret = 0;
	} else {
		ret = -1;
	}
	ifnet_head_done();
	return ret;
}

int
dlil_node_present(struct ifnet *ifp, struct sockaddr *sa,
    int32_t rssi, int lqm, int npm, u_int8_t srvinfo[48])
{
	struct kev_dl_node_presence kev;
	struct sockaddr_dl *sdl;
	struct sockaddr_in6 *sin6;
	int ret = 0;

	VERIFY(ifp);
	VERIFY(sa);
	VERIFY(sa->sa_family == AF_LINK || sa->sa_family == AF_INET6);

	bzero(&kev, sizeof(kev));
	sin6 = &kev.sin6_node_address;
	sdl = &kev.sdl_node_address;
	nd6_alt_node_addr_decompose(ifp, sa, sdl, sin6);
	kev.rssi = rssi;
	kev.link_quality_metric = lqm;
	kev.node_proximity_metric = npm;
	bcopy(srvinfo, kev.node_service_info, sizeof(kev.node_service_info));

	ret = nd6_alt_node_present(ifp, sin6, sdl, rssi, lqm, npm);
	if (ret == 0 || ret == EEXIST) {
		int err = dlil_post_msg(ifp, KEV_DL_SUBCLASS, KEV_DL_NODE_PRESENCE,
		    &kev.link_data, sizeof(kev), (ret == EEXIST) ? TRUE : FALSE);
		if (err != 0) {
			log(LOG_ERR, "%s: Post DL_NODE_PRESENCE failed with"
			    "error %d\n", __func__, err);
		}
	}

	if (ret == EEXIST) {
		ret = 0;
	}
	return ret;
}

void
dlil_node_absent(struct ifnet *ifp, struct sockaddr *sa)
{
	struct kev_dl_node_absence kev = {};
	struct sockaddr_in6 *kev_sin6 = NULL;
	struct sockaddr_dl *kev_sdl = NULL;
	int error = 0;

	VERIFY(ifp != NULL);
	VERIFY(sa != NULL);
	VERIFY(sa->sa_family == AF_LINK || sa->sa_family == AF_INET6);

	kev_sin6 = &kev.sin6_node_address;
	kev_sdl = &kev.sdl_node_address;

	if (sa->sa_family == AF_INET6) {
		/*
		 * If IPv6 address is given, get the link layer
		 * address from what was cached in the neighbor cache
		 */
		VERIFY(sa->sa_len <= sizeof(*kev_sin6));
		SOCKADDR_COPY(sa, kev_sin6, sa->sa_len);
		error = nd6_alt_node_absent(ifp, kev_sin6, kev_sdl);
	} else {
		/*
		 * If passed address is AF_LINK type, derive the address
		 * based on the link address.
		 */
		nd6_alt_node_addr_decompose(ifp, sa, kev_sdl, kev_sin6);
		error = nd6_alt_node_absent(ifp, kev_sin6, NULL);
	}

	if (error == 0) {
		kev_sdl->sdl_type = ifp->if_type;
		kev_sdl->sdl_index = ifp->if_index;

		dlil_post_msg(ifp, KEV_DL_SUBCLASS, KEV_DL_NODE_ABSENCE,
		    &kev.link_data, sizeof(kev), FALSE);
	}
}

int
dlil_node_present_v2(struct ifnet *ifp, struct sockaddr *sa, struct sockaddr_dl *sdl,
    int32_t rssi, int lqm, int npm, u_int8_t srvinfo[48])
{
	struct kev_dl_node_presence kev = {};
	struct sockaddr_dl *kev_sdl = NULL;
	struct sockaddr_in6 *kev_sin6 = NULL;
	int ret = 0;

	VERIFY(ifp != NULL);
	VERIFY(sa != NULL && sdl != NULL);
	VERIFY(sa->sa_family == AF_INET6 && sdl->sdl_family == AF_LINK);

	kev_sin6 = &kev.sin6_node_address;
	kev_sdl = &kev.sdl_node_address;

	VERIFY(sdl->sdl_len <= sizeof(*kev_sdl));
	SOCKADDR_COPY(sdl, kev_sdl, sdl->sdl_len);
	kev_sdl->sdl_type = ifp->if_type;
	kev_sdl->sdl_index = ifp->if_index;

	VERIFY(sa->sa_len <= sizeof(*kev_sin6));
	SOCKADDR_COPY(sa, kev_sin6, sa->sa_len);

	kev.rssi = rssi;
	kev.link_quality_metric = lqm;
	kev.node_proximity_metric = npm;
	bcopy(srvinfo, kev.node_service_info, sizeof(kev.node_service_info));

	ret = nd6_alt_node_present(ifp, SIN6(sa), sdl, rssi, lqm, npm);
	if (ret == 0 || ret == EEXIST) {
		int err = dlil_post_msg(ifp, KEV_DL_SUBCLASS, KEV_DL_NODE_PRESENCE,
		    &kev.link_data, sizeof(kev), (ret == EEXIST) ? TRUE : FALSE);
		if (err != 0) {
			log(LOG_ERR, "%s: Post DL_NODE_PRESENCE failed with error %d\n", __func__, err);
		}
	}

	if (ret == EEXIST) {
		ret = 0;
	}
	return ret;
}

const void *
dlil_ifaddr_bytes(const struct sockaddr_dl *sdl, size_t *sizep,
    kauth_cred_t *credp)
{
	const u_int8_t *bytes;
	size_t size;

	bytes = CONST_LLADDR(sdl);
	size = sdl->sdl_alen;

#if CONFIG_MACF
	if (dlil_lladdr_ckreq) {
		switch (sdl->sdl_type) {
		case IFT_ETHER:
		case IFT_IEEE1394:
			break;
		default:
			credp = NULL;
			break;
		}
		;

		if (credp && mac_system_check_info(*credp, "net.link.addr")) {
			static const u_int8_t unspec[FIREWIRE_EUI64_LEN] = {
				[0] = 2
			};

			bytes = unspec;
		}
	}
#else
#pragma unused(credp)
#endif

	if (sizep != NULL) {
		*sizep = size;
	}
	return bytes;
}

void
dlil_report_issues(struct ifnet *ifp, u_int8_t modid[DLIL_MODIDLEN],
    u_int8_t info[DLIL_MODARGLEN])
{
	struct kev_dl_issues kev;
	struct timeval tv;

	VERIFY(ifp != NULL);
	VERIFY(modid != NULL);
	_CASSERT(sizeof(kev.modid) == DLIL_MODIDLEN);
	_CASSERT(sizeof(kev.info) == DLIL_MODARGLEN);

	bzero(&kev, sizeof(kev));

	microtime(&tv);
	kev.timestamp = tv.tv_sec;
	bcopy(modid, &kev.modid, DLIL_MODIDLEN);
	if (info != NULL) {
		bcopy(info, &kev.info, DLIL_MODARGLEN);
	}

	dlil_post_msg(ifp, KEV_DL_SUBCLASS, KEV_DL_ISSUES,
	    &kev.link_data, sizeof(kev), FALSE);
}

errno_t
ifnet_getset_opportunistic(ifnet_t ifp, u_long cmd, struct ifreq *ifr,
    struct proc *p)
{
	u_int32_t level = IFNET_THROTTLE_OFF;
	errno_t result = 0;

	VERIFY(cmd == SIOCSIFOPPORTUNISTIC || cmd == SIOCGIFOPPORTUNISTIC);

	if (cmd == SIOCSIFOPPORTUNISTIC) {
		/*
		 * XXX: Use priv_check_cred() instead of root check?
		 */
		if ((result = proc_suser(p)) != 0) {
			return result;
		}

		if (ifr->ifr_opportunistic.ifo_flags ==
		    IFRIFOF_BLOCK_OPPORTUNISTIC) {
			level = IFNET_THROTTLE_OPPORTUNISTIC;
		} else if (ifr->ifr_opportunistic.ifo_flags == 0) {
			level = IFNET_THROTTLE_OFF;
		} else {
			result = EINVAL;
		}

		if (result == 0) {
			result = ifnet_set_throttle(ifp, level);
		}
	} else if ((result = ifnet_get_throttle(ifp, &level)) == 0) {
		ifr->ifr_opportunistic.ifo_flags = 0;
		if (level == IFNET_THROTTLE_OPPORTUNISTIC) {
			ifr->ifr_opportunistic.ifo_flags |=
			    IFRIFOF_BLOCK_OPPORTUNISTIC;
		}
	}

	/*
	 * Return the count of current opportunistic connections
	 * over the interface.
	 */
	if (result == 0) {
		uint32_t flags = 0;
		flags |= (cmd == SIOCSIFOPPORTUNISTIC) ?
		    INPCB_OPPORTUNISTIC_SETCMD : 0;
		flags |= (level == IFNET_THROTTLE_OPPORTUNISTIC) ?
		    INPCB_OPPORTUNISTIC_THROTTLEON : 0;
		ifr->ifr_opportunistic.ifo_inuse =
		    udp_count_opportunistic(ifp->if_index, flags) +
		    tcp_count_opportunistic(ifp->if_index, flags);
	}

	if (result == EALREADY) {
		result = 0;
	}

	return result;
}

int
ifnet_get_throttle(struct ifnet *ifp, u_int32_t *level)
{
	struct ifclassq *ifq;
	int err = 0;

	if (!(ifp->if_eflags & IFEF_TXSTART)) {
		return ENXIO;
	}

	*level = IFNET_THROTTLE_OFF;

	ifq = ifp->if_snd;
	IFCQ_LOCK(ifq);
	/* Throttling works only for IFCQ, not ALTQ instances */
	if (IFCQ_IS_ENABLED(ifq)) {
		cqrq_throttle_t req = { 0, IFNET_THROTTLE_OFF };

		err = fq_if_request_classq(ifq, CLASSQRQ_THROTTLE, &req);
		*level = req.level;
	}
	IFCQ_UNLOCK(ifq);

	return err;
}

int
ifnet_set_throttle(struct ifnet *ifp, u_int32_t level)
{
	struct ifclassq *ifq;
	int err = 0;

	if (!(ifp->if_eflags & IFEF_TXSTART)) {
		return ENXIO;
	}

	ifq = ifp->if_snd;

	switch (level) {
	case IFNET_THROTTLE_OFF:
	case IFNET_THROTTLE_OPPORTUNISTIC:
		break;
	default:
		return EINVAL;
	}

	IFCQ_LOCK(ifq);
	if (IFCQ_IS_ENABLED(ifq)) {
		cqrq_throttle_t req = { 1, level };

		err = fq_if_request_classq(ifq, CLASSQRQ_THROTTLE, &req);
	}
	IFCQ_UNLOCK(ifq);

	if (err == 0) {
		DLIL_PRINTF("%s: throttling level set to %d\n", if_name(ifp),
		    level);
#if NECP
		necp_update_all_clients();
#endif /* NECP */
		if (level == IFNET_THROTTLE_OFF) {
			ifnet_start(ifp);
		}
	}

	return err;
}

errno_t
ifnet_getset_log(ifnet_t ifp, u_long cmd, struct ifreq *ifr,
    struct proc *p)
{
#pragma unused(p)
	errno_t result = 0;
	uint32_t flags;
	int level, category, subcategory;

	VERIFY(cmd == SIOCSIFLOG || cmd == SIOCGIFLOG);

	if (cmd == SIOCSIFLOG) {
		if ((result = priv_check_cred(kauth_cred_get(),
		    PRIV_NET_INTERFACE_CONTROL, 0)) != 0) {
			return result;
		}

		level = ifr->ifr_log.ifl_level;
		if (level < IFNET_LOG_MIN || level > IFNET_LOG_MAX) {
			result = EINVAL;
		}

		flags = ifr->ifr_log.ifl_flags;
		if ((flags &= IFNET_LOGF_MASK) == 0) {
			result = EINVAL;
		}

		category = ifr->ifr_log.ifl_category;
		subcategory = ifr->ifr_log.ifl_subcategory;

		if (result == 0) {
			result = ifnet_set_log(ifp, level, flags,
			    category, subcategory);
		}
	} else {
		result = ifnet_get_log(ifp, &level, &flags, &category,
		    &subcategory);
		if (result == 0) {
			ifr->ifr_log.ifl_level = level;
			ifr->ifr_log.ifl_flags = flags;
			ifr->ifr_log.ifl_category = category;
			ifr->ifr_log.ifl_subcategory = subcategory;
		}
	}

	return result;
}

int
ifnet_set_log(struct ifnet *ifp, int32_t level, uint32_t flags,
    int32_t category, int32_t subcategory)
{
	int err = 0;

	VERIFY(level >= IFNET_LOG_MIN && level <= IFNET_LOG_MAX);
	VERIFY(flags & IFNET_LOGF_MASK);

	/*
	 * The logging level applies to all facilities; make sure to
	 * update them all with the most current level.
	 */
	flags |= ifp->if_log.flags;

	if (ifp->if_output_ctl != NULL) {
		struct ifnet_log_params l;

		bzero(&l, sizeof(l));
		l.level = level;
		l.flags = flags;
		l.flags &= ~IFNET_LOGF_DLIL;
		l.category = category;
		l.subcategory = subcategory;

		/* Send this request to lower layers */
		if (l.flags != 0) {
			err = ifp->if_output_ctl(ifp, IFNET_CTL_SET_LOG,
			    sizeof(l), &l);
		}
	} else if ((flags & ~IFNET_LOGF_DLIL) && ifp->if_output_ctl == NULL) {
		/*
		 * If targeted to the lower layers without an output
		 * control callback registered on the interface, just
		 * silently ignore facilities other than ours.
		 */
		flags &= IFNET_LOGF_DLIL;
		if (flags == 0 && (!(ifp->if_log.flags & IFNET_LOGF_DLIL))) {
			level = 0;
		}
	}

	if (err == 0) {
		if ((ifp->if_log.level = level) == IFNET_LOG_DEFAULT) {
			ifp->if_log.flags = 0;
		} else {
			ifp->if_log.flags |= flags;
		}

		log(LOG_INFO, "%s: logging level set to %d flags=0x%x "
		    "arg=0x%x, category=%d subcategory=%d\n", if_name(ifp),
		    ifp->if_log.level, ifp->if_log.flags, flags,
		    category, subcategory);
	}

	return err;
}

int
ifnet_get_log(struct ifnet *ifp, int32_t *level, uint32_t *flags,
    int32_t *category, int32_t *subcategory)
{
	if (level != NULL) {
		*level = ifp->if_log.level;
	}
	if (flags != NULL) {
		*flags = ifp->if_log.flags;
	}
	if (category != NULL) {
		*category = ifp->if_log.category;
	}
	if (subcategory != NULL) {
		*subcategory = ifp->if_log.subcategory;
	}

	return 0;
}

int
ifnet_notify_address(struct ifnet *ifp, int af)
{
	struct ifnet_notify_address_params na;

#if PF
	(void) pf_ifaddr_hook(ifp);
#endif /* PF */

	if (ifp->if_output_ctl == NULL) {
		return EOPNOTSUPP;
	}

	bzero(&na, sizeof(na));
	na.address_family = (sa_family_t)af;

	return ifp->if_output_ctl(ifp, IFNET_CTL_NOTIFY_ADDRESS,
	           sizeof(na), &na);
}

errno_t
ifnet_flowid(struct ifnet *ifp, uint32_t *flowid)
{
	if (ifp == NULL || flowid == NULL) {
		return EINVAL;
	} else if (!(ifp->if_eflags & IFEF_TXSTART) ||
	    !IF_FULLY_ATTACHED(ifp)) {
		return ENXIO;
	}

	*flowid = ifp->if_flowhash;

	return 0;
}

errno_t
ifnet_disable_output(struct ifnet *ifp)
{
	int err = 0;

	if (ifp == NULL) {
		return EINVAL;
	} else if (!(ifp->if_eflags & IFEF_TXSTART) ||
	    !IF_FULLY_ATTACHED(ifp)) {
		return ENXIO;
	}

	lck_mtx_lock(&ifp->if_start_lock);
	if (ifp->if_start_flags & IFSF_FLOW_RESUME_PENDING) {
		ifp->if_start_flags &= ~(IFSF_FLOW_RESUME_PENDING | IFSF_FLOW_CONTROLLED);
	} else if ((err = ifnet_fc_add(ifp)) == 0) {
		ifp->if_start_flags |= IFSF_FLOW_CONTROLLED;
	}
	lck_mtx_unlock(&ifp->if_start_lock);

	return err;
}

errno_t
ifnet_enable_output(struct ifnet *ifp)
{
	if (ifp == NULL) {
		return EINVAL;
	} else if (!(ifp->if_eflags & IFEF_TXSTART) ||
	    !IF_FULLY_ATTACHED(ifp)) {
		return ENXIO;
	}

	ifnet_start_common(ifp, TRUE, FALSE);
	return 0;
}

void
ifnet_flowadv(uint32_t flowhash)
{
	struct ifnet_fc_entry *ifce;
	ifnet_ref_t ifp;

	ifce = ifnet_fc_get(flowhash);
	if (ifce == NULL) {
		return;
	}

	VERIFY(ifce->ifce_ifp != NULL);
	ifp = ifce->ifce_ifp;

	/* flow hash gets recalculated per attach, so check */
	if (ifnet_is_attached(ifp, 1)) {
		if (ifp->if_flowhash == flowhash) {
			lck_mtx_lock_spin(&ifp->if_start_lock);
			if ((ifp->if_start_flags & IFSF_FLOW_CONTROLLED) == 0) {
				ifp->if_start_flags |= IFSF_FLOW_RESUME_PENDING;
			}
			lck_mtx_unlock(&ifp->if_start_lock);
			(void) ifnet_enable_output(ifp);
		}
		ifnet_decr_iorefcnt(ifp);
	}
	ifnet_fc_entry_free(ifce);
}

/*
 * Function to compare ifnet_fc_entries in ifnet flow control tree
 */
static inline int
ifce_cmp(const struct ifnet_fc_entry *fc1, const struct ifnet_fc_entry *fc2)
{
	return fc1->ifce_flowhash - fc2->ifce_flowhash;
}

static int
ifnet_fc_add(struct ifnet *ifp)
{
	struct ifnet_fc_entry keyfc, *ifce;
	uint32_t flowhash;

	VERIFY(ifp != NULL && (ifp->if_eflags & IFEF_TXSTART));
	VERIFY(ifp->if_flowhash != 0);
	flowhash = ifp->if_flowhash;

	bzero(&keyfc, sizeof(keyfc));
	keyfc.ifce_flowhash = flowhash;

	lck_mtx_lock_spin(&ifnet_fc_lock);
	ifce = RB_FIND(ifnet_fc_tree, &ifnet_fc_tree, &keyfc);
	if (ifce != NULL && ifce->ifce_ifp == ifp) {
		/* Entry is already in ifnet_fc_tree, return */
		lck_mtx_unlock(&ifnet_fc_lock);
		return 0;
	}

	if (ifce != NULL) {
		/*
		 * There is a different fc entry with the same flow hash
		 * but different ifp pointer.  There can be a collision
		 * on flow hash but the probability is low.  Let's just
		 * avoid adding a second one when there is a collision.
		 */
		lck_mtx_unlock(&ifnet_fc_lock);
		return EAGAIN;
	}

	/* become regular mutex */
	lck_mtx_convert_spin(&ifnet_fc_lock);

	ifce = zalloc_flags(ifnet_fc_zone, Z_WAITOK | Z_ZERO);
	ifce->ifce_flowhash = flowhash;
	ifce->ifce_ifp = ifp;

	RB_INSERT(ifnet_fc_tree, &ifnet_fc_tree, ifce);
	lck_mtx_unlock(&ifnet_fc_lock);
	return 0;
}

static struct ifnet_fc_entry *
ifnet_fc_get(uint32_t flowhash)
{
	struct ifnet_fc_entry keyfc, *ifce;
	ifnet_ref_t ifp;

	bzero(&keyfc, sizeof(keyfc));
	keyfc.ifce_flowhash = flowhash;

	lck_mtx_lock_spin(&ifnet_fc_lock);
	ifce = RB_FIND(ifnet_fc_tree, &ifnet_fc_tree, &keyfc);
	if (ifce == NULL) {
		/* Entry is not present in ifnet_fc_tree, return */
		lck_mtx_unlock(&ifnet_fc_lock);
		return NULL;
	}

	RB_REMOVE(ifnet_fc_tree, &ifnet_fc_tree, ifce);

	VERIFY(ifce->ifce_ifp != NULL);
	ifp = ifce->ifce_ifp;

	/* become regular mutex */
	lck_mtx_convert_spin(&ifnet_fc_lock);

	if (!ifnet_is_attached(ifp, 0)) {
		/*
		 * This ifp is not attached or in the process of being
		 * detached; just don't process it.
		 */
		ifnet_fc_entry_free(ifce);
		ifce = NULL;
	}
	lck_mtx_unlock(&ifnet_fc_lock);

	return ifce;
}

static void
ifnet_fc_entry_free(struct ifnet_fc_entry *ifce)
{
	zfree(ifnet_fc_zone, ifce);
}

static uint32_t
ifnet_calc_flowhash(struct ifnet *ifp)
{
	struct ifnet_flowhash_key fh __attribute__((aligned(8)));
	uint32_t flowhash = 0;

	if (ifnet_flowhash_seed == 0) {
		ifnet_flowhash_seed = RandomULong();
	}

	bzero(&fh, sizeof(fh));

	(void) snprintf(fh.ifk_name, sizeof(fh.ifk_name), "%s", ifp->if_name);
	fh.ifk_unit = ifp->if_unit;
	fh.ifk_flags = ifp->if_flags;
	fh.ifk_eflags = ifp->if_eflags;
	fh.ifk_capabilities = ifp->if_capabilities;
	fh.ifk_capenable = ifp->if_capenable;
	fh.ifk_output_sched_model = ifp->if_output_sched_model;
	fh.ifk_rand1 = RandomULong();
	fh.ifk_rand2 = RandomULong();

try_again:
	flowhash = net_flowhash(&fh, sizeof(fh), ifnet_flowhash_seed);
	if (flowhash == 0) {
		/* try to get a non-zero flowhash */
		ifnet_flowhash_seed = RandomULong();
		goto try_again;
	}

	return flowhash;
}

int
ifnet_set_netsignature(struct ifnet *ifp, uint8_t family, uint8_t len,
    uint16_t flags, uint8_t *__sized_by(len) data)
{
#pragma unused(flags)
	int error = 0;

	switch (family) {
	case AF_INET:
		if_inetdata_lock_exclusive(ifp);
		if (IN_IFEXTRA(ifp) != NULL) {
			if (len == 0) {
				/* Allow clearing the signature */
				IN_IFEXTRA(ifp)->netsig_len = 0;
				bzero(IN_IFEXTRA(ifp)->netsig,
				    sizeof(IN_IFEXTRA(ifp)->netsig));
				if_inetdata_lock_done(ifp);
				break;
			} else if (len > sizeof(IN_IFEXTRA(ifp)->netsig)) {
				error = EINVAL;
				if_inetdata_lock_done(ifp);
				break;
			}
			IN_IFEXTRA(ifp)->netsig_len = len;
			bcopy(data, IN_IFEXTRA(ifp)->netsig, len);
		} else {
			error = ENOMEM;
		}
		if_inetdata_lock_done(ifp);
		break;

	case AF_INET6:
		if_inet6data_lock_exclusive(ifp);
		if (IN6_IFEXTRA(ifp) != NULL) {
			if (len == 0) {
				/* Allow clearing the signature */
				IN6_IFEXTRA(ifp)->netsig_len = 0;
				bzero(IN6_IFEXTRA(ifp)->netsig,
				    sizeof(IN6_IFEXTRA(ifp)->netsig));
				if_inet6data_lock_done(ifp);
				break;
			} else if (len > sizeof(IN6_IFEXTRA(ifp)->netsig)) {
				error = EINVAL;
				if_inet6data_lock_done(ifp);
				break;
			}
			IN6_IFEXTRA(ifp)->netsig_len = len;
			bcopy(data, IN6_IFEXTRA(ifp)->netsig, len);
		} else {
			error = ENOMEM;
		}
		if_inet6data_lock_done(ifp);
		break;

	default:
		error = EINVAL;
		break;
	}

	return error;
}

int
ifnet_get_netsignature(struct ifnet *ifp, uint8_t family, uint8_t *len,
    uint16_t *flags, uint8_t *__sized_by(*len) data)
{
	int error = 0;

	if (ifp == NULL || len == NULL || data == NULL) {
		return EINVAL;
	}

	switch (family) {
	case AF_INET:
		if_inetdata_lock_shared(ifp);
		if (IN_IFEXTRA(ifp) != NULL) {
			if (*len == 0 || *len < IN_IFEXTRA(ifp)->netsig_len) {
				error = EINVAL;
				if_inetdata_lock_done(ifp);
				break;
			}
			if ((*len = (uint8_t)IN_IFEXTRA(ifp)->netsig_len) > 0) {
				bcopy(IN_IFEXTRA(ifp)->netsig, data, *len);
			} else {
				error = ENOENT;
			}
		} else {
			error = ENOMEM;
		}
		if_inetdata_lock_done(ifp);
		break;

	case AF_INET6:
		if_inet6data_lock_shared(ifp);
		if (IN6_IFEXTRA(ifp) != NULL) {
			if (*len == 0 || *len < IN6_IFEXTRA(ifp)->netsig_len) {
				error = EINVAL;
				if_inet6data_lock_done(ifp);
				break;
			}
			if ((*len = (uint8_t)IN6_IFEXTRA(ifp)->netsig_len) > 0) {
				bcopy(IN6_IFEXTRA(ifp)->netsig, data, *len);
			} else {
				error = ENOENT;
			}
		} else {
			error = ENOMEM;
		}
		if_inet6data_lock_done(ifp);
		break;

	default:
		error = EINVAL;
		break;
	}

	if (error == 0 && flags != NULL) {
		*flags = 0;
	}

	return error;
}

int
ifnet_set_nat64prefix(struct ifnet *ifp,
    struct ipv6_prefix *__counted_by(NAT64_MAX_NUM_PREFIXES) prefixes)
{
	int i, error = 0, one_set = 0;

	if_inet6data_lock_exclusive(ifp);

	if (IN6_IFEXTRA(ifp) == NULL) {
		error = ENOMEM;
		goto out;
	}

	for (i = 0; i < NAT64_MAX_NUM_PREFIXES; i++) {
		uint32_t prefix_len =
		    prefixes[i].prefix_len;
		struct in6_addr *prefix =
		    &prefixes[i].ipv6_prefix;

		if (prefix_len == 0) {
			clat_log0((LOG_DEBUG,
			    "NAT64 prefixes purged from Interface %s\n",
			    if_name(ifp)));
			/* Allow clearing the signature */
			IN6_IFEXTRA(ifp)->nat64_prefixes[i].prefix_len = 0;
			bzero(&IN6_IFEXTRA(ifp)->nat64_prefixes[i].ipv6_prefix,
			    sizeof(struct in6_addr));

			continue;
		} else if (prefix_len != NAT64_PREFIX_LEN_32 &&
		    prefix_len != NAT64_PREFIX_LEN_40 &&
		    prefix_len != NAT64_PREFIX_LEN_48 &&
		    prefix_len != NAT64_PREFIX_LEN_56 &&
		    prefix_len != NAT64_PREFIX_LEN_64 &&
		    prefix_len != NAT64_PREFIX_LEN_96) {
			clat_log0((LOG_DEBUG,
			    "NAT64 prefixlen is incorrect %d\n", prefix_len));
			error = EINVAL;
			goto out;
		}

		if (IN6_IS_SCOPE_EMBED(prefix)) {
			clat_log0((LOG_DEBUG,
			    "NAT64 prefix has interface/link local scope.\n"));
			error = EINVAL;
			goto out;
		}

		IN6_IFEXTRA(ifp)->nat64_prefixes[i].prefix_len = prefix_len;
		bcopy(prefix, &IN6_IFEXTRA(ifp)->nat64_prefixes[i].ipv6_prefix,
		    sizeof(struct in6_addr));
		clat_log0((LOG_DEBUG,
		    "NAT64 prefix set to %s with prefixlen: %d\n",
		    ip6_sprintf(prefix), prefix_len));
		one_set = 1;
	}

out:
	if_inet6data_lock_done(ifp);

	if (error == 0 && one_set != 0) {
		necp_update_all_clients();
	}

	return error;
}

int
ifnet_get_nat64prefix(struct ifnet *ifp,
    struct ipv6_prefix *__counted_by(NAT64_MAX_NUM_PREFIXES) prefixes)
{
	int i, found_one = 0, error = 0;

	if (ifp == NULL) {
		return EINVAL;
	}

	if_inet6data_lock_shared(ifp);

	if (IN6_IFEXTRA(ifp) == NULL) {
		error = ENOMEM;
		goto out;
	}

	for (i = 0; i < NAT64_MAX_NUM_PREFIXES; i++) {
		if (IN6_IFEXTRA(ifp)->nat64_prefixes[i].prefix_len != 0) {
			found_one = 1;
		}
	}

	if (found_one == 0) {
		error = ENOENT;
		goto out;
	}

	if (prefixes) {
		bcopy(IN6_IFEXTRA(ifp)->nat64_prefixes, prefixes,
		    sizeof(IN6_IFEXTRA(ifp)->nat64_prefixes));
	}

out:
	if_inet6data_lock_done(ifp);

	return error;
}

#if DEBUG || DEVELOPMENT
/* Blob for sum16 verification */
static uint8_t sumdata[] = {
	0x1f, 0x8b, 0x08, 0x08, 0x4c, 0xe5, 0x9a, 0x4f, 0x00, 0x03,
	0x5f, 0x00, 0x5d, 0x91, 0x41, 0x4e, 0xc4, 0x30, 0x0c, 0x45,
	0xf7, 0x9c, 0xc2, 0x07, 0x18, 0xf5, 0x0e, 0xb0, 0xe2, 0x00,
	0x48, 0x88, 0xa5, 0xdb, 0xba, 0x49, 0x34, 0x69, 0xdc, 0x71,
	0x92, 0xa9, 0xc2, 0x8a, 0x6b, 0x70, 0x3d, 0x4e, 0x82, 0x93,
	0xb4, 0x08, 0xd8, 0xc5, 0xb1, 0xfd, 0xff, 0xb3, 0xfd, 0x4c,
	0x42, 0x5f, 0x1f, 0x9f, 0x11, 0x12, 0x43, 0xb2, 0x04, 0x93,
	0xe0, 0x7b, 0x01, 0x0e, 0x14, 0x07, 0x78, 0xd1, 0x78, 0x75,
	0x71, 0x71, 0xe9, 0x08, 0x84, 0x46, 0xf2, 0xc7, 0x3b, 0x09,
	0xe7, 0xd1, 0xd3, 0x8a, 0x57, 0x92, 0x33, 0xcd, 0x39, 0xcc,
	0xb0, 0x91, 0x89, 0xe0, 0x42, 0x53, 0x8b, 0xb7, 0x8c, 0x42,
	0x60, 0xd9, 0x9f, 0x7a, 0x55, 0x19, 0x76, 0xcb, 0x10, 0x49,
	0x35, 0xac, 0x0b, 0x5a, 0x3c, 0xbb, 0x65, 0x51, 0x8c, 0x90,
	0x7c, 0x69, 0x45, 0x45, 0x81, 0xb4, 0x2b, 0x70, 0x82, 0x85,
	0x55, 0x91, 0x17, 0x90, 0xdc, 0x14, 0x1e, 0x35, 0x52, 0xdd,
	0x02, 0x16, 0xef, 0xb5, 0x40, 0x89, 0xe2, 0x46, 0x53, 0xad,
	0x93, 0x6e, 0x98, 0x30, 0xe5, 0x08, 0xb7, 0xcc, 0x03, 0xbc,
	0x71, 0x86, 0x09, 0x43, 0x0d, 0x52, 0xf5, 0xa2, 0xf5, 0xa2,
	0x56, 0x11, 0x8d, 0xa8, 0xf5, 0xee, 0x92, 0x3d, 0xfe, 0x8c,
	0x67, 0x71, 0x8b, 0x0e, 0x2d, 0x70, 0x77, 0xbe, 0xbe, 0xea,
	0xbf, 0x9a, 0x8d, 0x9c, 0x53, 0x53, 0xe5, 0xe0, 0x4b, 0x87,
	0x85, 0xd2, 0x45, 0x95, 0x30, 0xc1, 0xcc, 0xe0, 0x74, 0x54,
	0x13, 0x58, 0xe8, 0xe8, 0x79, 0xa2, 0x09, 0x73, 0xa4, 0x0e,
	0x39, 0x59, 0x0c, 0xe6, 0x9c, 0xb2, 0x4f, 0x06, 0x5b, 0x8e,
	0xcd, 0x17, 0x6c, 0x5e, 0x95, 0x4d, 0x70, 0xa2, 0x0a, 0xbf,
	0xa3, 0xcc, 0x03, 0xbc, 0x5a, 0xe7, 0x75, 0x06, 0x5e, 0x75,
	0xef, 0x58, 0x8e, 0x15, 0xd1, 0x0a, 0x18, 0xff, 0xdd, 0xe6,
	0x02, 0x3b, 0xb5, 0xb4, 0xa1, 0xe0, 0x72, 0xfc, 0xe3, 0xab,
	0x07, 0xe0, 0x4d, 0x65, 0xea, 0x92, 0xeb, 0xf2, 0x7b, 0x17,
	0x05, 0xce, 0xc6, 0xf6, 0x2b, 0xbb, 0x70, 0x3d, 0x00, 0x95,
	0xe0, 0x07, 0x52, 0x3b, 0x58, 0xfc, 0x7c, 0x69, 0x4d, 0xe9,
	0xf7, 0xa9, 0x66, 0x1e, 0x1e, 0xbe, 0x01, 0x69, 0x98, 0xfe,
	0xc8, 0x28, 0x02, 0x00, 0x00
};

/* Precomputed 16-bit 1's complement sums for various spans of the above data */
static struct {
	boolean_t       init;
	uint16_t        len;
	uint16_t        sumr;   /* reference */
	uint16_t        sumrp;  /* reference, precomputed */
} sumtbl[] = {
	{ FALSE, 0, 0, 0x0000 },
	{ FALSE, 1, 0, 0x001f },
	{ FALSE, 2, 0, 0x8b1f },
	{ FALSE, 3, 0, 0x8b27 },
	{ FALSE, 7, 0, 0x790e },
	{ FALSE, 11, 0, 0xcb6d },
	{ FALSE, 20, 0, 0x20dd },
	{ FALSE, 27, 0, 0xbabd },
	{ FALSE, 32, 0, 0xf3e8 },
	{ FALSE, 37, 0, 0x197d },
	{ FALSE, 43, 0, 0x9eae },
	{ FALSE, 64, 0, 0x4678 },
	{ FALSE, 127, 0, 0x9399 },
	{ FALSE, 256, 0, 0xd147 },
	{ FALSE, 325, 0, 0x0358 },
};
#define SUMTBL_MAX      ((int)sizeof (sumtbl) / (int)sizeof (sumtbl[0]))

static void
dlil_verify_sum16(void)
{
	struct mbuf *m;
	uint8_t *buf;
	int n;

	/* Make sure test data plus extra room for alignment fits in cluster */
	_CASSERT((sizeof(sumdata) + (sizeof(uint64_t) * 2)) <= MCLBYTES);

	kprintf("DLIL: running SUM16 self-tests ... ");

	m = m_getcl(M_WAITOK, MT_DATA, M_PKTHDR);
	m_align(m, sizeof(sumdata) + (sizeof(uint64_t) * 2));

	buf = mtod(m, uint8_t *);               /* base address */

	for (n = 0; n < SUMTBL_MAX; n++) {
		uint16_t len = sumtbl[n].len;
		int i;

		/* Verify for all possible alignments */
		for (i = 0; i < (int)sizeof(uint64_t); i++) {
			uint16_t sum, sumr;
			uint8_t *c;

			/* Copy over test data to mbuf */
			VERIFY(len <= sizeof(sumdata));
			c = buf + i;
			bcopy(sumdata, c, len);

			/* Zero-offset test (align by data pointer) */
			m->m_data = (uintptr_t)c;
			m->m_len = len;
			sum = m_sum16(m, 0, len);

			if (!sumtbl[n].init) {
				sumr = (uint16_t)in_cksum_mbuf_ref(m, len, 0, 0);
				sumtbl[n].sumr = sumr;
				sumtbl[n].init = TRUE;
			} else {
				sumr = sumtbl[n].sumr;
			}

			/* Something is horribly broken; stop now */
			if (sumr != sumtbl[n].sumrp) {
				panic_plain("\n%s: broken in_cksum_mbuf_ref() "
				    "for len=%d align=%d sum=0x%04x "
				    "[expected=0x%04x]\n", __func__,
				    len, i, sum, sumr);
				/* NOTREACHED */
			} else if (sum != sumr) {
				panic_plain("\n%s: broken m_sum16() for len=%d "
				    "align=%d sum=0x%04x [expected=0x%04x]\n",
				    __func__, len, i, sum, sumr);
				/* NOTREACHED */
			}

			/* Alignment test by offset (fixed data pointer) */
			m->m_data = (uintptr_t)buf;
			m->m_len = i + len;
			sum = m_sum16(m, i, len);

			/* Something is horribly broken; stop now */
			if (sum != sumr) {
				panic_plain("\n%s: broken m_sum16() for len=%d "
				    "offset=%d sum=0x%04x [expected=0x%04x]\n",
				    __func__, len, i, sum, sumr);
				/* NOTREACHED */
			}
#if INET
			/* Simple sum16 contiguous buffer test by aligment */
			sum = b_sum16(c, len);

			/* Something is horribly broken; stop now */
			if (sum != sumr) {
				panic_plain("\n%s: broken b_sum16() for len=%d "
				    "align=%d sum=0x%04x [expected=0x%04x]\n",
				    __func__, len, i, sum, sumr);
				/* NOTREACHED */
			}
#endif /* INET */
		}
	}
	m_freem(m);

	kprintf("PASSED\n");
}
#endif /* DEBUG || DEVELOPMENT */

#define CASE_STRINGIFY(x) case x: return #x

__private_extern__ const char *
dlil_kev_dl_code_str(u_int32_t event_code)
{
	switch (event_code) {
		CASE_STRINGIFY(KEV_DL_SIFFLAGS);
		CASE_STRINGIFY(KEV_DL_SIFMETRICS);
		CASE_STRINGIFY(KEV_DL_SIFMTU);
		CASE_STRINGIFY(KEV_DL_SIFPHYS);
		CASE_STRINGIFY(KEV_DL_SIFMEDIA);
		CASE_STRINGIFY(KEV_DL_SIFGENERIC);
		CASE_STRINGIFY(KEV_DL_ADDMULTI);
		CASE_STRINGIFY(KEV_DL_DELMULTI);
		CASE_STRINGIFY(KEV_DL_IF_ATTACHED);
		CASE_STRINGIFY(KEV_DL_IF_DETACHING);
		CASE_STRINGIFY(KEV_DL_IF_DETACHED);
		CASE_STRINGIFY(KEV_DL_LINK_OFF);
		CASE_STRINGIFY(KEV_DL_LINK_ON);
		CASE_STRINGIFY(KEV_DL_PROTO_ATTACHED);
		CASE_STRINGIFY(KEV_DL_PROTO_DETACHED);
		CASE_STRINGIFY(KEV_DL_LINK_ADDRESS_CHANGED);
		CASE_STRINGIFY(KEV_DL_WAKEFLAGS_CHANGED);
		CASE_STRINGIFY(KEV_DL_IF_IDLE_ROUTE_REFCNT);
		CASE_STRINGIFY(KEV_DL_IFCAP_CHANGED);
		CASE_STRINGIFY(KEV_DL_LINK_QUALITY_METRIC_CHANGED);
		CASE_STRINGIFY(KEV_DL_NODE_PRESENCE);
		CASE_STRINGIFY(KEV_DL_NODE_ABSENCE);
		CASE_STRINGIFY(KEV_DL_PRIMARY_ELECTED);
		CASE_STRINGIFY(KEV_DL_ISSUES);
		CASE_STRINGIFY(KEV_DL_IFDELEGATE_CHANGED);
	default:
		break;
	}
	return "";
}

void
dlil_dt_tcall_fn(thread_call_param_t arg0, thread_call_param_t arg1)
{
#pragma unused(arg1)
	ifnet_ref_t ifp = arg0;

	if (ifnet_is_attached(ifp, 1)) {
		nstat_ifnet_threshold_reached(ifp->if_index);
		ifnet_decr_iorefcnt(ifp);
	}
}

void
ifnet_notify_data_threshold(struct ifnet *ifp)
{
	uint64_t bytes = (ifp->if_ibytes + ifp->if_obytes);
	uint64_t oldbytes = ifp->if_dt_bytes;

	ASSERT(ifp->if_dt_tcall != NULL);

	/*
	 * If we went over the threshold, notify NetworkStatistics.
	 * We rate-limit it based on the threshold interval value.
	 */
	if (threshold_notify && (bytes - oldbytes) > ifp->if_data_threshold &&
	    OSCompareAndSwap64(oldbytes, bytes, &ifp->if_dt_bytes) &&
	    !thread_call_isactive(ifp->if_dt_tcall)) {
		uint64_t tival = (threshold_interval * NSEC_PER_SEC);
		uint64_t now = mach_absolute_time(), deadline = now;
		uint64_t ival;

		if (tival != 0) {
			nanoseconds_to_absolutetime(tival, &ival);
			clock_deadline_for_periodic_event(ival, now, &deadline);
			(void) thread_call_enter_delayed(ifp->if_dt_tcall,
			    deadline);
		} else {
			(void) thread_call_enter(ifp->if_dt_tcall);
		}
	}
}


void
ifnet_update_stats_per_flow(struct ifnet_stats_per_flow *ifs,
    struct ifnet *ifp)
{
	tcp_update_stats_per_flow(ifs, ifp);
}

static inline u_int32_t
_set_flags(u_int32_t *flags_p, u_int32_t set_flags)
{
	return (u_int32_t)OSBitOrAtomic(set_flags, flags_p);
}

static inline u_int32_t
_clear_flags(u_int32_t *flags_p, u_int32_t clear_flags)
{
	return (u_int32_t)OSBitAndAtomic(~clear_flags, flags_p);
}

__private_extern__ u_int32_t
if_set_eflags(ifnet_t interface, u_int32_t set_flags)
{
	return _set_flags(&interface->if_eflags, set_flags);
}

__private_extern__ void
if_clear_eflags(ifnet_t interface, u_int32_t clear_flags)
{
	_clear_flags(&interface->if_eflags, clear_flags);
}

__private_extern__ u_int32_t
if_set_xflags(ifnet_t interface, u_int32_t set_flags)
{
	return _set_flags(&interface->if_xflags, set_flags);
}

__private_extern__ u_int32_t
if_clear_xflags(ifnet_t interface, u_int32_t clear_flags)
{
	return _clear_flags(&interface->if_xflags, clear_flags);
}

__private_extern__ void
ifnet_update_traffic_rule_genid(ifnet_t ifp)
{
	os_atomic_inc(&ifp->if_traffic_rule_genid, relaxed);
}

__private_extern__ boolean_t
ifnet_sync_traffic_rule_genid(ifnet_t ifp, uint32_t *genid)
{
	if (*genid != ifp->if_traffic_rule_genid) {
		*genid = ifp->if_traffic_rule_genid;
		return TRUE;
	}
	return FALSE;
}
__private_extern__ void
ifnet_update_traffic_rule_count(ifnet_t ifp, uint32_t count)
{
	os_atomic_store(&ifp->if_traffic_rule_count, count, release);
	ifnet_update_traffic_rule_genid(ifp);
}


#if SKYWALK
static bool
net_check_compatible_if_filter(struct ifnet *ifp)
{
	if (ifp == NULL) {
		if (net_api_stats.nas_iflt_attach_count > net_api_stats.nas_iflt_attach_os_count) {
			return false;
		}
	} else {
		if (ifp->if_flt_non_os_count > 0) {
			return false;
		}
	}
	return true;
}
#endif /* SKYWALK */

#define DUMP_BUF_CHK() {        \
	clen -= k;              \
	if (clen < 1)           \
	        goto done;      \
	c += k;                 \
}

int dlil_dump_top_if_qlen(char *__counted_by(str_len), int str_len);
int
dlil_dump_top_if_qlen(char *__counted_by(str_len) str, int str_len)
{
	char *c = str;
	int k, clen = str_len;
	ifnet_ref_t top_ifcq_ifp = NULL;
	uint32_t top_ifcq_len = 0;
	ifnet_ref_t top_inq_ifp = NULL;
	uint32_t top_inq_len = 0;

	for (int ifidx = 1; ifidx < if_index; ifidx++) {
		ifnet_ref_t ifp = ifindex2ifnet[ifidx];
		struct dlil_ifnet *dl_if = (struct dlil_ifnet *)ifp;

		if (ifp == NULL) {
			continue;
		}
		if (ifp->if_snd != NULL && ifp->if_snd->ifcq_len > top_ifcq_len) {
			top_ifcq_len = ifp->if_snd->ifcq_len;
			top_ifcq_ifp = ifp;
		}
		if (dl_if->dl_if_inpstorage.dlth_pkts.qlen > top_inq_len) {
			top_inq_len = dl_if->dl_if_inpstorage.dlth_pkts.qlen;
			top_inq_ifp = ifp;
		}
	}

	if (top_ifcq_ifp != NULL) {
		k = scnprintf(c, clen, "\ntop ifcq_len %u packets by %s\n",
		    top_ifcq_len, top_ifcq_ifp->if_xname);
		DUMP_BUF_CHK();
	}
	if (top_inq_ifp != NULL) {
		k = scnprintf(c, clen, "\ntop inq_len %u packets by %s\n",
		    top_inq_len, top_inq_ifp->if_xname);
		DUMP_BUF_CHK();
	}
done:
	return str_len - clen;
}