147 lines
4.1 KiB
C
147 lines
4.1 KiB
C
/* Get source filter. Linux version.
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Copyright (C) 2004-2014 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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Contributed by Ulrich Drepper <drepper@redhat.com>, 2004.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, see
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<http://www.gnu.org/licenses/>. */
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#include <alloca.h>
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#include <assert.h>
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#include <errno.h>
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#include <stdlib.h>
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#include <string.h>
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#include <stdint.h>
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#include <netatalk/at.h>
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#include <netax25/ax25.h>
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#include <netinet/in.h>
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#include <netipx/ipx.h>
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#include <netpacket/packet.h>
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#include <netrose/rose.h>
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#include <sys/param.h>
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#include <sys/socket.h>
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static const struct
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{
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int sol;
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int af;
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socklen_t size;
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} sol_map[] =
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{
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/* Sort the array according to importance of the protocols. Add
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more protocols when they become available. */
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{ SOL_IP, AF_INET, sizeof (struct sockaddr_in) },
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{ SOL_IPV6, AF_INET6, sizeof (struct sockaddr_in6) },
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{ SOL_AX25, AF_AX25, sizeof (struct sockaddr_ax25) },
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{ SOL_IPX, AF_IPX, sizeof (struct sockaddr_ipx) },
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{ SOL_ATALK, AF_APPLETALK, sizeof (struct sockaddr_at) },
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{ SOL_ROSE, AF_ROSE, sizeof (struct sockaddr_rose) },
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{ SOL_PACKET, AF_PACKET, sizeof (struct sockaddr_ll) }
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};
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#define NSOL_MAP (sizeof (sol_map) / sizeof (sol_map[0]))
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/* Try to determine the socket level value. Ideally both side and
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family are set. But sometimes only the size is correct and the
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family value might be bogus. Loop over the array entries and look
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for a perfect match or the first match based on size. */
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int
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__get_sol (int af, socklen_t len)
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{
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int first_size_sol = -1;
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for (size_t cnt = 0; cnt < NSOL_MAP; ++cnt)
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{
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/* Just a test so that we make sure the special value used to
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signal the "we have so far no socket level value" is OK. */
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assert (sol_map[cnt].sol != -1);
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if (len == sol_map[cnt].size)
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{
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/* The size matches, which is a requirement. If the family
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matches, too, we have a winner. Otherwise we remember the
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socket level value for this protocol if it is the first
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match. */
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if (af == sol_map[cnt].af)
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/* Bingo! */
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return sol_map[cnt].sol;
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if (first_size_sol == -1)
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first_size_sol = sol_map[cnt].sol;
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}
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}
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return first_size_sol;
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}
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int
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getsourcefilter (int s, uint32_t interface, const struct sockaddr *group,
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socklen_t grouplen, uint32_t *fmode, uint32_t *numsrc,
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struct sockaddr_storage *slist)
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{
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/* We have to create an struct ip_msfilter object which we can pass
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to the kernel. */
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socklen_t needed = GROUP_FILTER_SIZE (*numsrc);
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int use_alloca = __libc_use_alloca (needed);
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struct group_filter *gf;
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if (use_alloca)
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gf = (struct group_filter *) alloca (needed);
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else
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{
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gf = (struct group_filter *) malloc (needed);
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if (gf == NULL)
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return -1;
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}
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gf->gf_interface = interface;
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memcpy (&gf->gf_group, group, grouplen);
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gf->gf_numsrc = *numsrc;
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/* We need to provide the appropriate socket level value. */
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int result;
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int sol = __get_sol (group->sa_family, grouplen);
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if (sol == -1)
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{
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__set_errno (EINVAL);
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result = -1;
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}
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else
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{
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result = __getsockopt (s, sol, MCAST_MSFILTER, gf, &needed);
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/* If successful, copy the results to the places the caller wants
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them in. */
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if (result == 0)
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{
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*fmode = gf->gf_fmode;
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memcpy (slist, gf->gf_slist,
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MIN (*numsrc, gf->gf_numsrc)
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* sizeof (struct sockaddr_storage));
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*numsrc = gf->gf_numsrc;
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}
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}
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if (! use_alloca)
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{
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int save_errno = errno;
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free (gf);
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__set_errno (save_errno);
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}
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return result;
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}
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