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1 | /***************************************************************************** |
2 | Copyright (c) 2006 EMC Corporation. | |
3 | ||
4 | This program is free software; you can redistribute it and/or modify it | |
5 | under the terms of the GNU General Public License as published by the Free | |
6 | Software Foundation; either version 2 of the License, or (at your option) | |
7 | any later version. | |
8 | ||
9 | This program is distributed in the hope that it will be useful, but WITHOUT | |
10 | ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
11 | FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for | |
12 | more details. | |
13 | ||
14 | You should have received a copy of the GNU General Public License along with | |
15 | this program; if not, write to the Free Software Foundation, Inc., 59 | |
16 | Temple Place - Suite 330, Boston, MA 02111-1307, USA. | |
17 | ||
18 | The full GNU General Public License is included in this distribution in the | |
19 | file called LICENSE. | |
20 | ||
21 | Authors: Srinivas Aji <Aji_Srinivas@emc.com> | |
22 | Stephen Hemminger <shemminger@linux-foundation.org> | |
23 | ||
24 | ******************************************************************************/ | |
25 | ||
26 | #include "packet.h" | |
27 | #include "epoll_loop.h" | |
28 | #include "netif_utils.h" | |
29 | #include "bridge_ctl.h" | |
30 | ||
31 | #include <stdio.h> | |
32 | #include <stdlib.h> | |
33 | #include <errno.h> | |
34 | #include <string.h> | |
35 | #include <unistd.h> | |
36 | #include <stdint.h> | |
37 | #include <sys/socket.h> | |
38 | #include <sys/ioctl.h> | |
39 | #include <fcntl.h> | |
40 | #include <netinet/in.h> | |
41 | ||
42 | #include <linux/if.h> | |
43 | #include <linux/if_ether.h> | |
44 | #include <linux/if_packet.h> | |
45 | #include <linux/filter.h> | |
46 | ||
47 | #include "log.h" | |
48 | ||
49 | #define DEBUG 1 | |
50 | ||
51 | /* | |
52 | * To send/receive Spanning Tree packets we use PF_PACKET because | |
53 | * it allows the filtering we want but gives raw data | |
54 | */ | |
55 | void packet_send(struct epoll_event_handler *h, unsigned char *data, int len) | |
56 | { | |
57 | int l; | |
58 | ||
59 | if (fcntl(h->fd, F_SETFL, 0) < 0) | |
60 | ERROR("Error unsetting O_NONBLOCK: %m"); | |
61 | ||
62 | l = send(h->fd, data, len, 0); | |
63 | if (l < 0) | |
64 | ERROR("send failed: %m"); | |
65 | else if (l != len) | |
66 | ERROR("short write in sendto: %d instead of %d", l, len); | |
67 | ||
68 | if (fcntl(h->fd, F_SETFL, O_NONBLOCK) < 0) | |
69 | ERROR("Error setting O_NONBLOCK: %m"); | |
70 | } | |
71 | ||
72 | void packet_rcv_handler(uint32_t events, struct epoll_event_handler *h) | |
73 | { | |
74 | int cc; | |
75 | unsigned char buf[2048]; | |
76 | ||
77 | cc = recv(h->fd, &buf, sizeof(buf), 0); | |
78 | if (cc <= 0) { | |
79 | ERROR("read failed: %m"); | |
80 | return; | |
81 | } | |
82 | ||
83 | #ifdef DEBUG | |
84 | printf("Src %02x:%02x:%02x:%02x:%02x:%02x\n", | |
85 | buf[0], buf[1], buf[2], buf[3], buf[4], buf[5]); | |
86 | ||
87 | int i, j; | |
88 | for (i = 0; i < cc; i += 16) { | |
89 | for (j = 0; j < 16 && i + j < cc; j++) | |
90 | printf(" %02x", buf[i + j]); | |
91 | printf("\n"); | |
92 | } | |
93 | printf("\n"); | |
94 | fflush(stdout); | |
95 | #endif | |
96 | ||
97 | bridge_bpdu_rcv(h->arg, buf, cc); | |
98 | } | |
99 | ||
100 | /* Berkeley Packet filter code to filter out spanning tree packets. | |
101 | from tcpdump -dd stp | |
102 | */ | |
103 | static struct sock_filter stp_filter[] = { | |
104 | { 0x28, 0, 0, 0x0000000c }, | |
105 | { 0x25, 3, 0, 0x000005dc }, | |
106 | { 0x30, 0, 0, 0x0000000e }, | |
107 | { 0x15, 0, 1, 0x00000042 }, | |
108 | { 0x6, 0, 0, 0x00000060 }, | |
109 | { 0x6, 0, 0, 0x00000000 }, | |
110 | }; | |
111 | ||
112 | /* | |
113 | * Open up a raw packet socket to catch all 802.2 packets on a device | |
114 | * and install a packet filter to only see STP (SAP 42) | |
115 | */ | |
116 | int packet_sock_create(struct epoll_event_handler *h, int if_index, | |
117 | struct ifdata *arg) | |
118 | { | |
119 | int s; | |
120 | struct sockaddr_ll sll = { | |
121 | .sll_family = AF_PACKET, | |
122 | .sll_ifindex = if_index, | |
123 | }; | |
124 | struct sock_fprog prog = { | |
125 | .len = sizeof(stp_filter) / sizeof(stp_filter[0]), | |
126 | .filter = stp_filter, | |
127 | }; | |
128 | ||
129 | s = socket(PF_PACKET, SOCK_PACKET, htons(ETH_P_802_2)); | |
130 | if (s < 0) { | |
131 | ERROR("socket failed: %m"); | |
132 | return -1; | |
133 | } | |
134 | ||
135 | if (bind(s, (struct sockaddr *) &sll, sizeof(sll)) < 0) | |
136 | ERROR("bind failed: %m"); | |
137 | ||
138 | else if (setsockopt(s, SOL_SOCKET, SO_ATTACH_FILTER, &prog, sizeof(prog)) < 0) | |
139 | ERROR("setsockopt packet filter failed: %m"); | |
140 | ||
141 | else if (fcntl(s, F_SETFL, O_NONBLOCK) < 0) | |
142 | ERROR("fcntl set nonblock failed: %m"); | |
143 | ||
144 | else { | |
145 | h->fd = s; | |
146 | h->arg = arg; | |
147 | h->handler = packet_rcv_handler; | |
148 | ||
149 | if (add_epoll(h) == 0) | |
150 | return 0; | |
151 | } | |
152 | ||
153 | close(s); | |
154 | return -1; | |
155 | } | |
156 | ||
157 | void packet_sock_delete(struct epoll_event_handler *h) | |
158 | { | |
159 | remove_epoll(h); | |
160 | close(h->fd); | |
161 | } |