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60f067b4 JS |
1 | /*** |
2 | This file is part of systemd. | |
3 | ||
4 | Copyright (C) 2014 Axis Communications AB. All rights reserved. | |
5 | ||
6 | systemd is free software; you can redistribute it and/or modify it | |
7 | under the terms of the GNU Lesser General Public License as published by | |
8 | the Free Software Foundation; either version 2.1 of the License, or | |
9 | (at your option) any later version. | |
10 | ||
11 | systemd is distributed in the hope that it will be useful, but | |
12 | 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 License | |
17 | along with systemd; If not, see <http://www.gnu.org/licenses/>. | |
18 | ***/ | |
19 | ||
20 | #include <linux/filter.h> | |
21 | ||
22 | #include "util.h" | |
23 | #include "ipv4ll-internal.h" | |
24 | ||
25 | int arp_network_send_raw_socket(int fd, const union sockaddr_union *link, | |
26 | const struct ether_arp *arp) { | |
27 | int r; | |
28 | ||
29 | assert(arp); | |
30 | assert(link); | |
31 | assert(fd >= 0); | |
32 | ||
33 | r = sendto(fd, arp, sizeof(struct ether_arp), 0, &link->sa, sizeof(link->ll)); | |
34 | if (r < 0) | |
35 | return -errno; | |
36 | ||
37 | return 0; | |
38 | } | |
39 | ||
5eef597e MP |
40 | int arp_network_bind_raw_socket(int ifindex, union sockaddr_union *link) { |
41 | ||
42 | static const struct sock_filter filter[] = { | |
43 | BPF_STMT(BPF_LD + BPF_W + BPF_LEN, 0), /* A <- packet length */ | |
44 | BPF_JUMP(BPF_JMP + BPF_JGE + BPF_K, sizeof(struct ether_arp), 1, 0), /* packet >= arp packet ? */ | |
45 | BPF_STMT(BPF_RET + BPF_K, 0), /* ignore */ | |
46 | BPF_STMT(BPF_LD + BPF_H + BPF_ABS, offsetof(struct ether_arp, ea_hdr.ar_hrd)), /* A <- header */ | |
47 | BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, ARPHRD_ETHER, 1, 0), /* header == ethernet ? */ | |
48 | BPF_STMT(BPF_RET + BPF_K, 0), /* ignore */ | |
49 | BPF_STMT(BPF_LD + BPF_H + BPF_ABS, offsetof(struct ether_arp, ea_hdr.ar_pro)), /* A <- protocol */ | |
50 | BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, ETHERTYPE_IP, 1, 0), /* protocol == IP ? */ | |
51 | BPF_STMT(BPF_RET + BPF_K, 0), /* ignore */ | |
52 | BPF_STMT(BPF_LD + BPF_H + BPF_ABS, offsetof(struct ether_arp, ea_hdr.ar_op)), /* A <- operation */ | |
53 | BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, ARPOP_REQUEST, 0, 1), /* protocol == request ? */ | |
54 | BPF_STMT(BPF_RET + BPF_K, 65535), /* return all */ | |
55 | BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, ARPOP_REPLY, 0, 1), /* protocol == reply ? */ | |
56 | BPF_STMT(BPF_RET + BPF_K, 65535), /* return all */ | |
57 | BPF_STMT(BPF_RET + BPF_K, 0), /* ignore */ | |
60f067b4 JS |
58 | }; |
59 | struct sock_fprog fprog = { | |
5eef597e MP |
60 | .len = ELEMENTSOF(filter), |
61 | .filter = (struct sock_filter*) filter | |
60f067b4 JS |
62 | }; |
63 | _cleanup_close_ int s = -1; | |
64 | int r; | |
65 | ||
5eef597e | 66 | assert(ifindex > 0); |
60f067b4 JS |
67 | assert(link); |
68 | ||
69 | s = socket(PF_PACKET, SOCK_DGRAM | SOCK_CLOEXEC | SOCK_NONBLOCK, 0); | |
70 | if (s < 0) | |
71 | return -errno; | |
72 | ||
73 | r = setsockopt(s, SOL_SOCKET, SO_ATTACH_FILTER, &fprog, sizeof(fprog)); | |
74 | if (r < 0) | |
75 | return -errno; | |
76 | ||
77 | link->ll.sll_family = AF_PACKET; | |
78 | link->ll.sll_protocol = htons(ETH_P_ARP); | |
5eef597e | 79 | link->ll.sll_ifindex = ifindex; |
60f067b4 JS |
80 | link->ll.sll_halen = ETH_ALEN; |
81 | memset(link->ll.sll_addr, 0xff, ETH_ALEN); | |
82 | ||
83 | r = bind(s, &link->sa, sizeof(link->ll)); | |
84 | if (r < 0) | |
85 | return -errno; | |
86 | ||
87 | r = s; | |
88 | s = -1; | |
89 | ||
90 | return r; | |
91 | } |