1/* Set IPv4 source filter. Linux version.
2 Copyright (C) 2004-2022 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
27
28int
29setipv4sourcefilter (int s, struct in_addr interface, struct in_addr group,
30 uint32_t fmode, uint32_t numsrc,
31 const struct in_addr *slist)
32{
33 /* We have to create an struct ip_msfilter object which we can pass
34 to the kernel. */
35 size_t needed = IP_MSFILTER_SIZE (numsrc);
36 int use_alloca = __libc_use_alloca (size: needed);
37
38 struct ip_msfilter *imsf;
39 if (use_alloca)
40 imsf = (struct ip_msfilter *) alloca (needed);
41 else
42 {
43 imsf = (struct ip_msfilter *) malloc (size: needed);
44 if (imsf == NULL)
45 return -1;
46 }
47
48 imsf->imsf_multiaddr = group;
49 imsf->imsf_interface = interface;
50 imsf->imsf_fmode = fmode;
51 imsf->imsf_numsrc = numsrc;
52 memcpy (imsf->imsf_slist, slist, numsrc * sizeof (struct in_addr));
53
54 int result = __setsockopt (s, SOL_IP, IP_MSFILTER, imsf, needed);
55
56 if (! use_alloca)
57 {
58 int save_errno = errno;
59 free (ptr: imsf);
60 __set_errno (save_errno);
61 }
62
63 return result;
64}
65

source code of glibc/sysdeps/unix/sysv/linux/setipv4sourcefilter.c