xref: /xnu-11417.140.69/bsd/kern/netboot.c (revision 43a90889846e00bfb5cf1d255cdc0a701a1e05a4)

/*
 * Copyright (c) 2001-2019 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@
 */

/*
 * History:
 * 14 December, 2001	Dieter Siegmund ([email protected])
 * - created
 */
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/conf.h>
#include <sys/ioctl.h>
#include <sys/proc_internal.h>
#include <sys/mount_internal.h>
#include <sys/mbuf.h>
#include <sys/filedesc.h>
#include <sys/vnode_internal.h>
#include <sys/malloc.h>
#include <sys/socket.h>
#include <sys/socketvar.h>
#include <sys/reboot.h>
#include <sys/kauth.h>
#include <net/if.h>
#include <net/if_dl.h>
#include <net/if_types.h>
#include <net/route.h>
#include <netinet/in.h>
#include <netinet/if_ether.h>
#include <netinet/dhcp_options.h>

#include <kern/kern_types.h>
#include <kern/kalloc.h>
#include <sys/netboot.h>
#include <sys/imageboot.h>
#include <pexpert/pexpert.h>

extern int (*mountroot)(void);

extern unsigned char    rootdevice[];

static int                      S_netboot = 0;
static struct netboot_info *    S_netboot_info_p;

void *
IOBSDRegistryEntryForDeviceTree(const char * path);

void
IOBSDRegistryEntryRelease(void * entry);

const void *
IOBSDRegistryEntryGetData(void * entry, const char * property_name,
    int * packet_length);

#define BOOTP_RESPONSE  "bootp-response"
#define BSDP_RESPONSE   "bsdp-response"
#define DHCP_RESPONSE   "dhcp-response"

#define IP_FORMAT       "%d.%d.%d.%d"
#define IP_CH(ip)       ((u_char *)ip)
#define IP_LIST(ip)     IP_CH(ip)[0],IP_CH(ip)[1],IP_CH(ip)[2],IP_CH(ip)[3]

#define kNetBootRootPathPrefixNFS       "nfs:"
#define kNetBootRootPathPrefixHTTP      "http:"

typedef enum {
	kNetBootImageTypeUnknown = 0,
	kNetBootImageTypeNFS = 1, // Deprecated
	kNetBootImageTypeHTTP = 2,
} NetBootImageType;

struct netboot_info {
	struct in_addr      client_ip;
	struct in_addr      server_ip;
	char *              server_name;
	size_t              server_name_length;
	char *              mount_point;
	size_t              mount_point_length;
	char *              image_path;
	size_t              image_path_length;
	NetBootImageType    image_type;
	char *              second_image_path;
	size_t              second_image_path_length;
};

/*
 * Function: parse_booter_path
 * Purpose:
 *   Parse a string of the form:
 *        "<IP>:<host>:<mount>[:<image_path>]"
 *   into the given ip address, host, mount point, and optionally, image_path.
 *
 * Note:
 *   The passed in string is modified i.e. ':' is replaced by '\0'.
 * Example:
 *   "17.202.16.17:seaport:/release/.images/Image9/CurrentHera"
 */
static __inline__ boolean_t
parse_booter_path(char * path, struct in_addr * iaddr_p, char const * * host,
    char * * mount_dir, char * * image_path)
{
	char *      start;
	char *      colon;

	/* IP address */
	start = path;
	colon = strchr(start, ':');
	if (colon == NULL) {
		return FALSE;
	}
	*colon = '\0';
	if (inet_aton(start, iaddr_p) != 1) {
		return FALSE;
	}

	/* host */
	start = colon + 1;
	colon = strchr(start, ':');
	if (colon == NULL) {
		return FALSE;
	}
	*colon = '\0';
	*host = start;

	/* mount */
	start = colon + 1;
	colon = strchr(start, ':');
	*mount_dir = start;
	if (colon == NULL) {
		*image_path = NULL;
	} else {
		/* image path */
		*colon = '\0';
		start = colon + 1;
		*image_path = start;
	}
	return TRUE;
}

/*
 * Function: find_colon
 * Purpose:
 *   Find the next unescaped instance of the colon character.
 *   If a colon is escaped (preceded by a backslash '\' character),
 *   shift the string over by one character to overwrite the backslash.
 */
static __inline__ char *
find_colon(char * str)
{
	char * start = str;
	char * colon;

	while ((colon = strchr(start, ':')) != NULL) {
		char * dst;
		char * src;

		if (colon == start) {
			break;
		}
		if (colon[-1] != '\\') {
			break;
		}
		for (dst = colon - 1, src = colon; *dst != '\0'; dst++, src++) {
			*dst = *src;
		}
		start = colon;
	}
	return colon;
}

/*
 * Function: parse_netboot_path
 * Purpose:
 *   Parse a string of the form:
 *        "nfs:<IP>:<mount>[:<image_path>]"
 *   into the given ip address, host, mount point, and optionally, image_path.
 * Notes:
 * - the passed in string is modified i.e. ':' is replaced by '\0'
 * - literal colons must be escaped with a backslash
 *
 * Examples:
 * nfs:17.202.42.112:/Library/NetBoot/NetBootSP0:Jaguar/Jaguar.dmg
 * nfs:17.202.42.112:/Volumes/Foo\:/Library/NetBoot/NetBootSP0:Jaguar/Jaguar.dmg
 */
static __inline__ boolean_t
parse_netboot_path(char * path, struct in_addr * iaddr_p, char const * * host,
    char * * mount_dir, char * * image_path)
{
	static char tmp[MAX_IPv4_STR_LEN]; /* Danger - not thread safe */
	char *      start;
	char *      colon;

	if (strncmp(path, kNetBootRootPathPrefixNFS,
	    strlen(kNetBootRootPathPrefixNFS)) != 0) {
		return FALSE;
	}

	/* IP address */
	start = path + strlen(kNetBootRootPathPrefixNFS);
	colon = strchr(start, ':');
	if (colon == NULL) {
		return FALSE;
	}
	*colon = '\0';
	if (inet_aton(start, iaddr_p) != 1) {
		return FALSE;
	}

	/* mount point */
	start = colon + 1;
	colon = find_colon(start);
	*mount_dir = start;
	if (colon == NULL) {
		*image_path = NULL;
	} else {
		/* image path */
		*colon = '\0';
		start = colon + 1;
		(void)find_colon(start);
		*image_path = start;
	}
	*host = inet_ntop(AF_INET, iaddr_p, tmp, sizeof(tmp));
	return TRUE;
}

static boolean_t
parse_image_path(char * path, struct in_addr * iaddr_p, char const * * host,
    char * * mount_dir, char * * image_path)
{
	if (path[0] >= '0' && path[0] <= '9') {
		return parse_booter_path(path, iaddr_p, host, mount_dir,
		           image_path);
	}
	return parse_netboot_path(path, iaddr_p, host, mount_dir,
	           image_path);
}

static boolean_t
get_root_path(char * root_path)
{
	void *              entry;
	boolean_t           found = FALSE;
	const void *        pkt;
	int                 pkt_len;

	entry = IOBSDRegistryEntryForDeviceTree("/chosen");
	if (entry == NULL) {
		return FALSE;
	}
	pkt = IOBSDRegistryEntryGetData(entry, BSDP_RESPONSE, &pkt_len);
	if (pkt != NULL && pkt_len >= (int)sizeof(struct dhcp)) {
		printf("netboot: retrieving root path from BSDP response\n");
	} else {
		pkt = IOBSDRegistryEntryGetData(entry, BOOTP_RESPONSE,
		    &pkt_len);
		if (pkt != NULL && pkt_len >= (int)sizeof(struct dhcp)) {
			printf("netboot: retrieving root path from BOOTP response\n");
		}
	}
	if (pkt != NULL) {
		int                     len;
		dhcpol_t                options;
		const char *            path;
		const struct dhcp *     reply;

		reply = (const struct dhcp *)pkt;
		(void)dhcpol_parse_packet(&options, reply, pkt_len);

		path = (const char *)dhcpol_find(&options,
		    dhcptag_root_path_e, &len, NULL);
		if (path) {
			memcpy(root_path, path, len);
			root_path[len] = '\0';
			found = TRUE;
		}
	}
	IOBSDRegistryEntryRelease(entry);
	return found;
}

static void
save_path(char * * str_p, size_t * length_p, char * path)
{
	*length_p = strlen(path) + 1;
	*str_p = kalloc_data(*length_p, Z_WAITOK);
	strlcpy(*str_p, path, *length_p);
	return;
}

static struct netboot_info *
netboot_info_init(struct in_addr iaddr)
{
	boolean_t                   have_root_path = FALSE;
	struct netboot_info *       info = NULL;
	char *                      root_path = NULL;

	info = (struct netboot_info *)kalloc_type(struct netboot_info, Z_WAITOK | Z_ZERO);
	info->client_ip = iaddr;
	info->image_type = kNetBootImageTypeUnknown;

	/* check for a booter-specified path then a NetBoot path */
	root_path = zalloc(ZV_NAMEI);

	if (PE_parse_boot_argn("rp0", root_path, MAXPATHLEN) == TRUE
	    || PE_parse_boot_argn("rp", root_path, MAXPATHLEN) == TRUE
	    || PE_parse_boot_argn("rootpath", root_path, MAXPATHLEN) == TRUE) {
		if (imageboot_format_is_valid(root_path)) {
			printf("netboot_info_init: rp0='%s' isn't a network path,"
			    " ignoring\n", root_path);
		} else {
			have_root_path = TRUE;
		}
	}
	if (have_root_path == FALSE) {
		have_root_path = get_root_path(root_path);
	}
	if (have_root_path) {
		const char * server_name = NULL;
		char * mount_point = NULL;
		char * image_path = NULL;
		struct in_addr  server_ip;

		if (parse_image_path(root_path, &server_ip, &server_name,
		    &mount_point, &image_path)) {
			/* kNetBootImageTypeNFS is deprecated */
			printf("netboot: NFS boot is deprecated\n");
		} else if (strncmp(root_path, kNetBootRootPathPrefixHTTP,
		    strlen(kNetBootRootPathPrefixHTTP)) == 0) {
			info->image_type = kNetBootImageTypeHTTP;
			save_path(&info->image_path, &info->image_path_length,
			    root_path);
			printf("netboot: HTTP URL %s\n", info->image_path);
		} else {
			printf("netboot: root path uses unrecognized format\n");
		}

		/* check for image-within-image */
		if (info->image_path != NULL) {
			if (PE_parse_boot_argn(IMAGEBOOT_ROOT_ARG, root_path, MAXPATHLEN)
			    || PE_parse_boot_argn("rp1", root_path, MAXPATHLEN)) {
				/* rp1/root-dmg is the second-level image */
				save_path(&info->second_image_path, &info->second_image_path_length,
				    root_path);
			}
		}
		if (info->second_image_path != NULL) {
			printf("netboot: nested image %s\n", info->second_image_path);
		}
	}
	zfree(ZV_NAMEI, root_path);
	return info;
}

static void
netboot_info_free(struct netboot_info * * info_p)
{
	struct netboot_info * info = *info_p;

	if (info) {
		kfree_data(info->mount_point, info->mount_point_length);
		kfree_data(info->server_name, info->server_name_length);
		kfree_data(info->image_path, info->image_path_length);
		kfree_data(info->second_image_path,
		    info->second_image_path_length);
		kfree_type(struct netboot_info, info);
	}
	*info_p = NULL;
}

boolean_t
netboot_iaddr(struct in_addr * iaddr_p)
{
	if (S_netboot_info_p == NULL) {
		return FALSE;
	}

	*iaddr_p = S_netboot_info_p->client_ip;
	return TRUE;
}

boolean_t
netboot_rootpath(struct in_addr * server_ip,
    char * name, size_t name_len,
    char * path, size_t path_len)
{
	if (S_netboot_info_p == NULL) {
		return FALSE;
	}

	name[0] = '\0';
	path[0] = '\0';

	if (S_netboot_info_p->mount_point_length == 0) {
		return FALSE;
	}
	if (path_len < S_netboot_info_p->mount_point_length) {
		printf("netboot: path too small %zu < %zu\n",
		    path_len, S_netboot_info_p->mount_point_length);
		return FALSE;
	}
	strlcpy(path, S_netboot_info_p->mount_point, path_len);
	strlcpy(name, S_netboot_info_p->server_name, name_len);
	*server_ip = S_netboot_info_p->server_ip;
	return TRUE;
}


static boolean_t
get_ip_parameters(struct in_addr * iaddr_p, struct in_addr * netmask_p,
    struct in_addr * router_p)
{
	void *              entry;
	const void *        pkt;
	int                 pkt_len;


	entry = IOBSDRegistryEntryForDeviceTree("/chosen");
	if (entry == NULL) {
		return FALSE;
	}
	pkt = IOBSDRegistryEntryGetData(entry, DHCP_RESPONSE, &pkt_len);
	if (pkt != NULL && pkt_len >= (int)sizeof(struct dhcp)) {
		printf("netboot: retrieving IP information from DHCP response\n");
	} else {
		pkt = IOBSDRegistryEntryGetData(entry, BOOTP_RESPONSE, &pkt_len);
		if (pkt != NULL && pkt_len >= (int)sizeof(struct dhcp)) {
			printf("netboot: retrieving IP information from BOOTP response\n");
		}
	}
	if (pkt != NULL) {
		const struct in_addr *  ip;
		int                     len;
		dhcpol_t                options;
		const struct dhcp *     reply;

		reply = (const struct dhcp *)pkt;
		(void)dhcpol_parse_packet(&options, reply, pkt_len);
		*iaddr_p = reply->dp_yiaddr;
		ip = (const struct in_addr *)
		    dhcpol_find(&options,
		    dhcptag_subnet_mask_e, &len, NULL);
		if (ip) {
			*netmask_p = *ip;
		}
		ip = (const struct in_addr *)
		    dhcpol_find(&options, dhcptag_router_e, &len, NULL);
		if (ip) {
			*router_p = *ip;
		}
	}
	IOBSDRegistryEntryRelease(entry);
	return pkt != NULL;
}

static int
route_cmd(int cmd, struct in_addr d, struct in_addr g,
    struct in_addr m, uint32_t more_flags, unsigned int ifscope)
{
	struct sockaddr_in          dst;
	int                         error;
	uint32_t                    flags = RTF_UP | RTF_STATIC;
	struct sockaddr_in          gw;
	struct sockaddr_in          mask;

	flags |= more_flags;

	/* destination */
	bzero((caddr_t)&dst, sizeof(dst));
	dst.sin_len = sizeof(dst);
	dst.sin_family = AF_INET;
	dst.sin_addr = d;

	/* gateway */
	bzero((caddr_t)&gw, sizeof(gw));
	gw.sin_len = sizeof(gw);
	gw.sin_family = AF_INET;
	gw.sin_addr = g;

	/* mask */
	bzero(&mask, sizeof(mask));
	mask.sin_len = sizeof(mask);
	mask.sin_family = AF_INET;
	mask.sin_addr = m;

	error = rtrequest_scoped(cmd, (struct sockaddr *)&dst,
	    (struct sockaddr *)&gw, (struct sockaddr *)&mask, flags, NULL, ifscope);

	return error;
}

static int
default_route_add(struct in_addr router, boolean_t proxy_arp)
{
	uint32_t                    flags = 0;
	struct in_addr              zeroes = { .s_addr = 0 };

	if (proxy_arp == FALSE) {
		flags |= RTF_GATEWAY;
	}
	return route_cmd(RTM_ADD, zeroes, router, zeroes, flags, IFSCOPE_NONE);
}

static struct ifnet *
find_interface(void)
{
	struct ifnet *              ifp = NULL;

	dlil_if_lock();
	if (rootdevice[0]) {
		ifp = ifunit((char *)rootdevice);
	}
	if (ifp == NULL) {
		ifnet_head_lock_shared();
		TAILQ_FOREACH(ifp, &ifnet_head, if_link)
		if ((ifp->if_flags & (IFF_LOOPBACK | IFF_POINTOPOINT)) == 0) {
			break;
		}
		ifnet_head_done();
	}
	dlil_if_unlock();
	return ifp;
}

static const struct sockaddr_in blank_sin = {
	.sin_len = sizeof(struct sockaddr_in),
	.sin_family = AF_INET,
	.sin_port = 0,
	.sin_addr = { .s_addr = 0 },
	.sin_zero = { 0, 0, 0, 0, 0, 0, 0, 0 }
};

static int
inet_aifaddr(struct socket * so, const char * name,
    const struct in_addr * addr,
    const struct in_addr * mask,
    const struct in_addr * broadcast)
{
	struct ifaliasreq   ifra;

	bzero(&ifra, sizeof(ifra));
	strlcpy(ifra.ifra_name, name, sizeof(ifra.ifra_name));
	if (addr) {
		*((struct sockaddr_in *)(void *)&ifra.ifra_addr) = blank_sin;
		((struct sockaddr_in *)(void *)&ifra.ifra_addr)->sin_addr = *addr;
	}
	if (mask) {
		*((struct sockaddr_in *)(void *)&ifra.ifra_mask) = blank_sin;
		((struct sockaddr_in *)(void *)&ifra.ifra_mask)->sin_addr = *mask;
	}
	if (broadcast) {
		*((struct sockaddr_in *)(void *)&ifra.ifra_broadaddr) = blank_sin;
		((struct sockaddr_in *)(void *)&ifra.ifra_broadaddr)->sin_addr = *broadcast;
	}
	return ifioctl(so, SIOCAIFADDR, (caddr_t)&ifra, current_proc());
}


int
netboot_mountroot(void)
{
	int                         error = 0;
	struct in_addr              iaddr = { .s_addr = 0 };
	struct ifreq                ifr;
	struct ifnet *              ifp;
	struct in_addr              netmask = { .s_addr = 0 };
	proc_t                      procp = current_proc();
	struct in_addr              router = { .s_addr = 0 };
	struct socket *             so = NULL;

	bzero(&ifr, sizeof(ifr));

	/* find the interface */
	ifp = find_interface();
	if (ifp == NULL) {
		printf("netboot: no suitable interface\n");
		error = ENXIO;
		goto failed;
	}
	snprintf(ifr.ifr_name, sizeof(ifr.ifr_name), "%s", if_name(ifp));
	printf("netboot: using network interface '%s'\n", ifr.ifr_name);

	/* bring it up */
	if ((error = socreate(AF_INET, &so, SOCK_DGRAM, 0)) != 0) {
		printf("netboot: socreate, error=%d\n", error);
		goto failed;
	}
	ifr.ifr_flags = ifp->if_flags | IFF_UP;
	error = ifioctl(so, SIOCSIFFLAGS, (caddr_t)&ifr, procp);
	if (error) {
		printf("netboot: SIFFLAGS, error=%d\n", error);
		goto failed;
	}

	/* grab information from the registry */
	if (get_ip_parameters(&iaddr, &netmask, &router) == FALSE) {
		printf("netboot: can't retrieve IP parameters\n");
		goto failed;
	}
	OS_ANALYZER_SUPPRESS("12641116") printf("netboot: IP address " IP_FORMAT, IP_LIST(&iaddr));
	if (netmask.s_addr) {
		printf(" netmask " IP_FORMAT, IP_LIST(&netmask));
	}
	if (router.s_addr) {
		printf(" router " IP_FORMAT, IP_LIST(&router));
	}
	printf("\n");
	error = inet_aifaddr(so, ifr.ifr_name, &iaddr, &netmask, NULL);
	if (error) {
		printf("netboot: inet_aifaddr failed, %d\n", error);
		goto failed;
	}
	if (router.s_addr == 0) {
		/* enable proxy arp if we don't have a router */
		router.s_addr = iaddr.s_addr;
	}
	printf("netboot: adding default route " IP_FORMAT "\n",
	    IP_LIST(&router));
	error = default_route_add(router, router.s_addr == iaddr.s_addr);
	if (error) {
		printf("netboot: default_route_add failed %d\n", error);
	}

	soclose(so);

	S_netboot_info_p = netboot_info_init(iaddr);
	switch (S_netboot_info_p->image_type) {
	default:
	case kNetBootImageTypeNFS:
		/* kNetBootImageTypeNFS is deprecated */
		error = ENOTSUP;
		break;
	case kNetBootImageTypeHTTP:
		error = netboot_setup();
		break;
	}
	if (error == 0) {
		S_netboot = 1;
	} else {
		S_netboot = 0;
	}
	return error;
failed:
	if (so != NULL) {
		soclose(so);
	}
	return error;
}

int
netboot_setup(void)
{
	int         error = 0;

	if (S_netboot_info_p == NULL
	    || S_netboot_info_p->image_path == NULL) {
		goto done;
	}
	printf("netboot_setup: calling imageboot_mount_image\n");
	error = imageboot_mount_image(S_netboot_info_p->image_path, -1, IMAGEBOOT_DMG);
	if (error != 0) {
		printf("netboot: failed to mount root image, %d\n", error);
	} else if (S_netboot_info_p->second_image_path != NULL) {
		error = imageboot_mount_image(S_netboot_info_p->second_image_path, 0, IMAGEBOOT_DMG);
		if (error != 0) {
			printf("netboot: failed to mount second root image, %d\n", error);
		}
	}

done:
	netboot_info_free(&S_netboot_info_p);
	return error;
}

int
netboot_root(void)
{
	return S_netboot;
}