1 /* Set source filter. Linux version.
2 Copyright (C) 2004-2021 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
4
5 The GNU C Library is free software; you can redistribute it and/or
6 modify it under the terms of the GNU Lesser General Public
7 License as published by the Free Software Foundation; either
8 version 2.1 of the License, or (at your option) any later version.
9
10 The GNU C Library is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 Lesser General Public License for more details.
14
15 You should have received a copy of the GNU Lesser General Public
16 License along with the GNU C Library; if not, see
17 <https://www.gnu.org/licenses/>. */
18
19 #include <alloca.h>
20 #include <errno.h>
21 #include <stdlib.h>
22 #include <string.h>
23 #include <stdint.h>
24 #include <netinet/in.h>
25 #include <sys/socket.h>
26 #include "getsourcefilter.h"
27
28
29 int
setsourcefilter(int s,uint32_t interface,const struct sockaddr * group,socklen_t grouplen,uint32_t fmode,uint32_t numsrc,const struct sockaddr_storage * slist)30 setsourcefilter (int s, uint32_t interface, const struct sockaddr *group,
31 socklen_t grouplen, uint32_t fmode, uint32_t numsrc,
32 const struct sockaddr_storage *slist)
33 {
34 /* We have to create an struct ip_msfilter object which we can pass
35 to the kernel. */
36 size_t needed = GROUP_FILTER_SIZE (numsrc);
37 int use_alloca = __libc_use_alloca (needed);
38
39 struct group_filter *gf;
40 if (use_alloca)
41 gf = (struct group_filter *) alloca (needed);
42 else
43 {
44 gf = (struct group_filter *) malloc (needed);
45 if (gf == NULL)
46 return -1;
47 }
48
49 gf->gf_interface = interface;
50 memcpy (&gf->gf_group, group, grouplen);
51 gf->gf_fmode = fmode;
52 gf->gf_numsrc = numsrc;
53 memcpy (gf->gf_slist, slist, numsrc * sizeof (struct sockaddr_storage));
54
55 /* We need to provide the appropriate socket level value. */
56 int result;
57 int sol = __get_sol (group->sa_family, grouplen);
58 if (sol == -1)
59 {
60 __set_errno (EINVAL);
61 result = -1;
62 }
63 else
64 result = __setsockopt (s, sol, MCAST_MSFILTER, gf, needed);
65
66 if (! use_alloca)
67 {
68 int save_errno = errno;
69 free (gf);
70 __set_errno (save_errno);
71 }
72
73 return result;
74 }
75