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1 | /*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/ |
2 | ||
3 | /*** | |
4 | This file is part of systemd. | |
5 | ||
6 | Copyright (C) 2014 Tom Gundersen | |
7 | Copyright (C) 2014 Susant Sahani | |
8 | ||
9 | systemd is free software; you can redistribute it and/or modify it | |
10 | under the terms of the GNU Lesser General Public License as published by | |
11 | the Free Software Foundation; either version 2.1 of the License, or | |
12 | (at your option) any later version. | |
13 | ||
14 | systemd is distributed in the hope that it will be useful, but | |
15 | WITHOUT ANY WARRANTY; without even the implied warranty of | |
16 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
17 | Lesser General Public License for more details. | |
18 | ||
19 | You should have received a copy of the GNU Lesser General Public License | |
20 | along with systemd; If not, see <http://www.gnu.org/licenses/>. | |
21 | ***/ | |
22 | ||
23 | #include <linux/filter.h> | |
24 | #include <linux/if_ether.h> | |
25 | ||
26 | #include "socket-util.h" | |
27 | #include "lldp-tlv.h" | |
28 | #include "lldp-network.h" | |
7a6f1457 | 29 | #include "lldp-internal.h" |
ad1ad5c8 SS |
30 | #include "sd-lldp.h" |
31 | ||
32 | int lldp_network_bind_raw_socket(int ifindex) { | |
33 | typedef struct LLDPFrame { | |
34 | struct ethhdr hdr; | |
35 | uint8_t tlvs[0]; | |
36 | } LLDPFrame; | |
37 | ||
38 | struct sock_filter filter[] = { | |
39 | BPF_STMT(BPF_LD + BPF_W + BPF_ABS, offsetof(LLDPFrame, hdr.h_dest)), /* A <- 4 bytes of destination MAC */ | |
40 | BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, 0x0180c200, 1, 0), /* A != 01:80:c2:00 */ | |
41 | BPF_STMT(BPF_RET + BPF_K, 0), /* drop packet */ | |
42 | BPF_STMT(BPF_LD + BPF_H + BPF_ABS, offsetof(LLDPFrame, hdr.h_dest) + 4), /* A <- remaining 2 bytes of destination MAC */ | |
43 | BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, 0x0000, 3, 0), /* A != 00:00 */ | |
44 | BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, 0x0003, 2, 0), /* A != 00:03 */ | |
45 | BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, 0x000e, 1, 0), /* A != 00:0e */ | |
46 | BPF_STMT(BPF_RET + BPF_K, 0), /* drop packet */ | |
47 | BPF_STMT(BPF_LD + BPF_H + BPF_ABS, offsetof(LLDPFrame, hdr.h_proto)), /* A <- protocol */ | |
48 | BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, ETHERTYPE_LLDP, 1, 0), /* A != ETHERTYPE_LLDP */ | |
49 | BPF_STMT(BPF_RET + BPF_K, 0), /* drop packet */ | |
50 | BPF_STMT(BPF_RET + BPF_K, (uint32_t) -1), /* accept packet */ | |
51 | }; | |
52 | ||
53 | struct sock_fprog fprog = { | |
54 | .len = ELEMENTSOF(filter), | |
55 | .filter = filter | |
56 | }; | |
57 | ||
58 | _cleanup_close_ int s = -1; | |
59 | ||
60 | union sockaddr_union saddrll = { | |
61 | .ll.sll_family = AF_PACKET, | |
62 | .ll.sll_ifindex = ifindex, | |
63 | }; | |
64 | ||
65 | int r; | |
66 | ||
67 | assert(ifindex > 0); | |
68 | ||
69 | s = socket(PF_PACKET, SOCK_RAW, htons(ETH_P_ALL)); | |
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 | r = bind(s, &saddrll.sa, sizeof(saddrll.ll)); | |
78 | if (r < 0) | |
79 | return -errno; | |
80 | ||
81 | r = s; | |
82 | s = -1; | |
83 | ||
84 | return r; | |
85 | } | |
86 | ||
87 | int lldp_receive_packet(sd_event_source *s, int fd, uint32_t revents, void *userdata) { | |
88 | _cleanup_tlv_packet_free_ tlv_packet *packet = NULL; | |
89 | tlv_packet *p; | |
90 | uint16_t length; | |
91 | int r; | |
92 | ||
93 | assert(fd); | |
94 | assert(userdata); | |
95 | ||
96 | r = tlv_packet_new(&packet); | |
97 | if (r < 0) | |
98 | return r; | |
99 | ||
100 | length = read(fd, &packet->pdu, sizeof(packet->pdu)); | |
101 | ||
102 | /* Silently drop the packet */ | |
103 | if ((size_t) length > ETHER_MAX_LEN) | |
104 | return 0; | |
105 | ||
106 | packet->userdata = userdata; | |
107 | ||
108 | p = packet; | |
109 | packet = NULL; | |
110 | ||
111 | return lldp_handle_packet(p, (uint16_t) length); | |
112 | } |