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489aa29d | 1 | /* Get source filter. Linux version. |
04277e02 | 2 | Copyright (C) 2004-2019 Free Software Foundation, Inc. |
489aa29d UD |
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 | |
59ba27a6 | 17 | License along with the GNU C Library; if not, see |
5a82c748 | 18 | <https://www.gnu.org/licenses/>. */ |
489aa29d UD |
19 | |
20 | #include <alloca.h> | |
9030e7c4 | 21 | #include <assert.h> |
489aa29d UD |
22 | #include <errno.h> |
23 | #include <stdlib.h> | |
24 | #include <string.h> | |
e054f494 | 25 | #include <stdint.h> |
9030e7c4 UD |
26 | #include <netatalk/at.h> |
27 | #include <netax25/ax25.h> | |
489aa29d | 28 | #include <netinet/in.h> |
9030e7c4 UD |
29 | #include <netipx/ipx.h> |
30 | #include <netpacket/packet.h> | |
31 | #include <netrose/rose.h> | |
32 | #include <sys/param.h> | |
489aa29d | 33 | #include <sys/socket.h> |
8369d216 | 34 | #include "getsourcefilter.h" |
489aa29d UD |
35 | |
36 | ||
9030e7c4 UD |
37 | static const struct |
38 | { | |
39 | int sol; | |
40 | int af; | |
41 | socklen_t size; | |
42 | } sol_map[] = | |
43 | { | |
44 | /* Sort the array according to importance of the protocols. Add | |
45 | more protocols when they become available. */ | |
46 | { SOL_IP, AF_INET, sizeof (struct sockaddr_in) }, | |
47 | { SOL_IPV6, AF_INET6, sizeof (struct sockaddr_in6) }, | |
48 | { SOL_AX25, AF_AX25, sizeof (struct sockaddr_ax25) }, | |
49 | { SOL_IPX, AF_IPX, sizeof (struct sockaddr_ipx) }, | |
50 | { SOL_ATALK, AF_APPLETALK, sizeof (struct sockaddr_at) }, | |
51 | { SOL_ROSE, AF_ROSE, sizeof (struct sockaddr_rose) }, | |
52 | { SOL_PACKET, AF_PACKET, sizeof (struct sockaddr_ll) } | |
53 | }; | |
54 | #define NSOL_MAP (sizeof (sol_map) / sizeof (sol_map[0])) | |
55 | ||
56 | ||
57 | /* Try to determine the socket level value. Ideally both side and | |
58 | family are set. But sometimes only the size is correct and the | |
59 | family value might be bogus. Loop over the array entries and look | |
60 | for a perfect match or the first match based on size. */ | |
61 | int | |
62 | __get_sol (int af, socklen_t len) | |
63 | { | |
64 | int first_size_sol = -1; | |
65 | ||
66 | for (size_t cnt = 0; cnt < NSOL_MAP; ++cnt) | |
67 | { | |
68 | /* Just a test so that we make sure the special value used to | |
69 | signal the "we have so far no socket level value" is OK. */ | |
70 | assert (sol_map[cnt].sol != -1); | |
71 | ||
72 | if (len == sol_map[cnt].size) | |
73 | { | |
74 | /* The size matches, which is a requirement. If the family | |
75 | matches, too, we have a winner. Otherwise we remember the | |
76 | socket level value for this protocol if it is the first | |
77 | match. */ | |
78 | if (af == sol_map[cnt].af) | |
79 | /* Bingo! */ | |
80 | return sol_map[cnt].sol; | |
81 | ||
82 | if (first_size_sol == -1) | |
83 | first_size_sol = sol_map[cnt].sol; | |
84 | } | |
85 | } | |
86 | ||
87 | return first_size_sol; | |
88 | } | |
89 | ||
90 | ||
489aa29d | 91 | int |
d3c99ad1 | 92 | getsourcefilter (int s, uint32_t interface, const struct sockaddr *group, |
489aa29d UD |
93 | socklen_t grouplen, uint32_t *fmode, uint32_t *numsrc, |
94 | struct sockaddr_storage *slist) | |
95 | { | |
96 | /* We have to create an struct ip_msfilter object which we can pass | |
97 | to the kernel. */ | |
98 | socklen_t needed = GROUP_FILTER_SIZE (*numsrc); | |
9030e7c4 | 99 | int use_alloca = __libc_use_alloca (needed); |
489aa29d UD |
100 | |
101 | struct group_filter *gf; | |
9030e7c4 UD |
102 | if (use_alloca) |
103 | gf = (struct group_filter *) alloca (needed); | |
104 | else | |
489aa29d UD |
105 | { |
106 | gf = (struct group_filter *) malloc (needed); | |
107 | if (gf == NULL) | |
108 | return -1; | |
109 | } | |
489aa29d UD |
110 | |
111 | gf->gf_interface = interface; | |
112 | memcpy (&gf->gf_group, group, grouplen); | |
9030e7c4 | 113 | gf->gf_numsrc = *numsrc; |
489aa29d | 114 | |
9030e7c4 | 115 | /* We need to provide the appropriate socket level value. */ |
0292b0dd | 116 | int result; |
9030e7c4 UD |
117 | int sol = __get_sol (group->sa_family, grouplen); |
118 | if (sol == -1) | |
119 | { | |
120 | __set_errno (EINVAL); | |
0292b0dd | 121 | result = -1; |
9030e7c4 | 122 | } |
0292b0dd | 123 | else |
a334319f | 124 | { |
0292b0dd UD |
125 | result = __getsockopt (s, sol, MCAST_MSFILTER, gf, &needed); |
126 | ||
127 | /* If successful, copy the results to the places the caller wants | |
128 | them in. */ | |
129 | if (result == 0) | |
130 | { | |
131 | *fmode = gf->gf_fmode; | |
132 | memcpy (slist, gf->gf_slist, | |
133 | MIN (*numsrc, gf->gf_numsrc) | |
134 | * sizeof (struct sockaddr_storage)); | |
135 | *numsrc = gf->gf_numsrc; | |
136 | } | |
489aa29d UD |
137 | } |
138 | ||
9030e7c4 | 139 | if (! use_alloca) |
489aa29d UD |
140 | { |
141 | int save_errno = errno; | |
142 | free (gf); | |
143 | __set_errno (save_errno); | |
144 | } | |
145 | ||
146 | return result; | |
147 | } |