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489aa29d | 1 | /* Get IPv4 source filter. Linux version. |
2b778ceb | 2 | Copyright (C) 2004-2021 Free Software Foundation, Inc. |
489aa29d | 3 | This file is part of the GNU C Library. |
489aa29d UD |
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 | |
59ba27a6 | 16 | License along with the GNU C Library; if not, see |
5a82c748 | 17 | <https://www.gnu.org/licenses/>. */ |
489aa29d UD |
18 | |
19 | #include <alloca.h> | |
20 | #include <errno.h> | |
21 | #include <stdlib.h> | |
22 | #include <string.h> | |
e054f494 | 23 | #include <stdint.h> |
489aa29d | 24 | #include <netinet/in.h> |
9030e7c4 | 25 | #include <sys/param.h> |
489aa29d UD |
26 | #include <sys/socket.h> |
27 | ||
28 | ||
29 | int | |
30 | getipv4sourcefilter (int s, struct in_addr interface, struct in_addr group, | |
31 | uint32_t *fmode, uint32_t *numsrc, struct in_addr *slist) | |
32 | { | |
33 | /* We have to create an struct ip_msfilter object which we can pass | |
34 | to the kernel. */ | |
35 | socklen_t needed = IP_MSFILTER_SIZE (*numsrc); | |
9030e7c4 | 36 | int use_alloca = __libc_use_alloca (needed); |
489aa29d UD |
37 | |
38 | struct ip_msfilter *imsf; | |
9030e7c4 UD |
39 | if (use_alloca) |
40 | imsf = (struct ip_msfilter *) alloca (needed); | |
41 | else | |
489aa29d UD |
42 | { |
43 | imsf = (struct ip_msfilter *) malloc (needed); | |
44 | if (imsf == NULL) | |
45 | return -1; | |
46 | } | |
489aa29d UD |
47 | |
48 | imsf->imsf_multiaddr = group; | |
49 | imsf->imsf_interface = interface; | |
9030e7c4 | 50 | imsf->imsf_numsrc = *numsrc; |
489aa29d UD |
51 | |
52 | int result = __getsockopt (s, SOL_IP, IP_MSFILTER, imsf, &needed); | |
53 | ||
54 | /* If successful, copy the results to the places the caller wants | |
55 | them in. */ | |
56 | if (result == 0) | |
57 | { | |
58 | *fmode = imsf->imsf_fmode; | |
489aa29d | 59 | memcpy (slist, imsf->imsf_slist, |
9030e7c4 UD |
60 | MIN (*numsrc, imsf->imsf_numsrc) * sizeof (struct in_addr)); |
61 | *numsrc = imsf->imsf_numsrc; | |
489aa29d UD |
62 | } |
63 | ||
9030e7c4 | 64 | if (! use_alloca) |
489aa29d UD |
65 | { |
66 | int save_errno = errno; | |
67 | free (imsf); | |
68 | __set_errno (save_errno); | |
69 | } | |
70 | ||
71 | return result; | |
72 | } |