1/* Get IPv4 source filter. Linux version.
2 Copyright (C) 2004-2021 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
4 Contributed by Ulrich Drepper <drepper@redhat.com>, 2004.
5
6 The GNU C Library is free software; you can redistribute it and/or
7 modify it under the terms of the GNU Lesser General Public
8 License as published by the Free Software Foundation; either
9 version 2.1 of the License, or (at your option) any later version.
10
11 The GNU C Library is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 Lesser General Public License for more details.
15
16 You should have received a copy of the GNU Lesser General Public
17 License along with the GNU C Library; if not, see
18 <https://www.gnu.org/licenses/>. */
19
20#include <alloca.h>
21#include <errno.h>
22#include <stdlib.h>
23#include <string.h>
24#include <stdint.h>
25#include <netinet/in.h>
26#include <sys/param.h>
27#include <sys/socket.h>
28
29
30int
31getipv4sourcefilter (int s, struct in_addr interface, struct in_addr group,
32 uint32_t *fmode, uint32_t *numsrc, struct in_addr *slist)
33{
34 /* We have to create an struct ip_msfilter object which we can pass
35 to the kernel. */
36 socklen_t needed = IP_MSFILTER_SIZE (*numsrc);
37 int use_alloca = __libc_use_alloca (needed);
38
39 struct ip_msfilter *imsf;
40 if (use_alloca)
41 imsf = (struct ip_msfilter *) alloca (needed);
42 else
43 {
44 imsf = (struct ip_msfilter *) malloc (needed);
45 if (imsf == NULL)
46 return -1;
47 }
48
49 imsf->imsf_multiaddr = group;
50 imsf->imsf_interface = interface;
51 imsf->imsf_numsrc = *numsrc;
52
53 int result = __getsockopt (s, SOL_IP, IP_MSFILTER, imsf, &needed);
54
55 /* If successful, copy the results to the places the caller wants
56 them in. */
57 if (result == 0)
58 {
59 *fmode = imsf->imsf_fmode;
60 memcpy (slist, imsf->imsf_slist,
61 MIN (*numsrc, imsf->imsf_numsrc) * sizeof (struct in_addr));
62 *numsrc = imsf->imsf_numsrc;
63 }
64
65 if (! use_alloca)
66 {
67 int save_errno = errno;
68 free (imsf);
69 __set_errno (save_errno);
70 }
71
72 return result;
73}
74