xref: /xnu-8792.61.2/bsd/net/multicast_list.c (revision 42e220869062b56f8d7d0726fd4c88954f87902c)

/*
 * Copyright (c) 2004-2021 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@
 */

/*
 * multicast_util.c:
 * - keep track of multicast addresses added to one interface based on the
 *   actual multicast addresses in another
 * - used by VLAN and BOND
 */

/*
 * Modification History:
 *
 * April 29, 2004	Dieter Siegmund ([email protected])
 * - created
 */

#include <net/multicast_list.h>
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/malloc.h>
#include <net/if_dl.h>

__private_extern__ void
multicast_list_init(struct multicast_list * mc_list)
{
	SLIST_INIT(mc_list);
	return;
}

/*
 * Function: multicast_list_remove
 * Purpose:
 *   Remove the given list of multicast addresses from the interface and from
 *   the multicast list structure.
 */
__private_extern__ int
multicast_list_remove(struct multicast_list * mc_list)
{
	int                         error;
	struct multicast_entry *    mc;
	int                         result = 0;

	while ((mc = SLIST_FIRST(mc_list)) != NULL) {
		error = ifnet_remove_multicast(mc->mc_ifma);
		if (error != 0) {
			result = error;
		}
		SLIST_REMOVE_HEAD(mc_list, mc_entries);
		ifmaddr_release(mc->mc_ifma);
		kfree_type(struct multicast_entry, mc);
	}
	return result;
}

/*
 * Function: multicast_list_program
 * Purpose:
 *   Program the multicast filter on "target_ifp" using the values from
 *   "source_ifp", and saving the result in "mc_list"
 *
 *   We build a new list of multicast addresses while programming the new list.
 *   If that completes successfully, we remove the old list, and return the
 *   new list.
 *
 *   If it fails, we remove what we've added to the new list, and
 *   return an error.
 */
__private_extern__ int
multicast_list_program(struct multicast_list * mc_list,
    struct ifnet * source_ifp,
    struct ifnet * target_ifp)
{
	u_char                      alen;
	int                         error = 0;
	int                         i;
	struct multicast_entry *    mc = NULL;
	struct multicast_list       new_mc_list;
	struct sockaddr_dl          source_sdl = {};
	ifmultiaddr_t *             source_multicast_list;
	struct sockaddr_dl          target_sdl;

	alen = target_ifp->if_addrlen;
	bzero((char *)&target_sdl, sizeof(target_sdl));
	target_sdl.sdl_len = sizeof(target_sdl);
	target_sdl.sdl_family = AF_LINK;
	target_sdl.sdl_type = target_ifp->if_type;
	target_sdl.sdl_alen = alen;
	target_sdl.sdl_index = target_ifp->if_index;

	/* build a new list */
	multicast_list_init(&new_mc_list);
	error = ifnet_get_multicast_list(source_ifp, &source_multicast_list);
	if (error != 0) {
		printf("multicast_list_program: "
		    "ifnet_get_multicast_list(%s%d) failed, %d\n",
		    source_ifp->if_name, source_ifp->if_unit, error);
		return error;
	}
	for (i = 0; source_multicast_list[i] != NULL; i++) {
		if (ifmaddr_address(source_multicast_list[i],
		    (struct sockaddr *)&source_sdl,
		    sizeof(source_sdl)) != 0
		    || source_sdl.sdl_family != AF_LINK) {
			continue;
		}
		mc = kalloc_type(struct multicast_entry, Z_WAITOK | Z_NOFAIL);
		bcopy(LLADDR(&source_sdl), LLADDR(&target_sdl), alen);
		error = ifnet_add_multicast(target_ifp, (struct sockaddr *)&target_sdl,
		    &mc->mc_ifma);
		if (error != 0) {
			kfree_type(struct multicast_entry, mc);
			break;
		}
		SLIST_INSERT_HEAD(&new_mc_list, mc, mc_entries);
	}
	if (error != 0) {
		/* restore previous state */
		(void)multicast_list_remove(&new_mc_list);
	} else {
		/* remove the old entries, and return the new list */
		(void)multicast_list_remove(mc_list);
		*mc_list = new_mc_list;
	}
	ifnet_free_multicast_list(source_multicast_list);
	return error;
}