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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 | Authors: Stephen Hemminger <shemminger@linux-foundation.org> | |
23 | ||
24 | ******************************************************************************/ | |
25 | ||
26 | /* #define PACKET_DEBUG */ | |
27 | ||
28 | #include <string.h> | |
29 | #include <unistd.h> | |
30 | #include <stdbool.h> | |
31 | #include <fcntl.h> | |
32 | #include <netinet/in.h> | |
33 | #include <linux/if_packet.h> | |
34 | #include <linux/filter.h> | |
c6ed0c4c | 35 | #include <asm/byteorder.h> |
1e6d2d09 VD |
36 | |
37 | #include "epoll_loop.h" | |
38 | #include "netif_utils.h" | |
39 | #include "bridge_ctl.h" | |
40 | #include "packet.h" | |
41 | #include "log.h" | |
42 | ||
43 | static struct epoll_event_handler packet_event; | |
44 | ||
45 | #ifdef PACKET_DEBUG | |
46 | static void dump_packet(const unsigned char *buf, int cc) | |
47 | { | |
48 | int i, j; | |
49 | for(i = 0; i < cc; i += 16) | |
50 | { | |
51 | for(j = 0; j < 16 && i + j < cc; ++j) | |
52 | printf(" %02x", buf[i + j]); | |
53 | printf("\n"); | |
54 | } | |
55 | printf("\n"); | |
56 | fflush(stdout); | |
57 | } | |
58 | #endif | |
59 | ||
60 | /* | |
61 | * To send/receive Spanning Tree packets we use PF_PACKET because | |
62 | * it allows the filtering we want but gives raw data | |
63 | */ | |
64 | void packet_send(int ifindex, const struct iovec *iov, int iov_count, int len) | |
65 | { | |
66 | int l; | |
67 | struct sockaddr_ll sl = | |
68 | { | |
69 | .sll_family = AF_PACKET, | |
c6ed0c4c | 70 | .sll_protocol = __constant_cpu_to_be16(ETH_P_802_2), |
1e6d2d09 VD |
71 | .sll_ifindex = ifindex, |
72 | .sll_halen = ETH_ALEN, | |
73 | }; | |
74 | ||
75 | if(iov_count > 0 && iov[0].iov_len > ETH_ALEN) | |
76 | memcpy(&sl.sll_addr, iov[0].iov_base, ETH_ALEN); | |
77 | ||
78 | struct msghdr msg = | |
79 | { | |
80 | .msg_name = &sl, | |
81 | .msg_namelen = sizeof(sl), | |
82 | .msg_iov = (struct iovec *)iov, | |
83 | .msg_iovlen = iov_count, | |
84 | .msg_control = NULL, | |
85 | .msg_controllen = 0, | |
86 | .msg_flags = 0, | |
87 | }; | |
88 | ||
89 | #ifdef PACKET_DEBUG | |
90 | printf("Transmit Dst index %d %02x:%02x:%02x:%02x:%02x:%02x\n", | |
91 | sl.sll_ifindex, | |
92 | sl.sll_addr[0], sl.sll_addr[1], sl.sll_addr[2], | |
93 | sl.sll_addr[3], sl.sll_addr[4], sl.sll_addr[5]); | |
94 | { | |
95 | int i; | |
96 | for(i = 0; i < iov_count; ++i) | |
97 | dump_packet(iov[i].iov_base, iov[i].iov_len); | |
98 | } | |
99 | #endif | |
100 | ||
101 | l = sendmsg(packet_event.fd, &msg, 0); | |
102 | ||
103 | if(l < 0) | |
104 | { | |
105 | if(errno != EWOULDBLOCK) | |
106 | ERROR("send failed: %m"); | |
107 | } | |
108 | else if(l != len) | |
109 | ERROR("short write in sendto: %d instead of %d", l, len); | |
110 | } | |
111 | ||
112 | static void packet_rcv(uint32_t events, struct epoll_event_handler *h) | |
113 | { | |
114 | int cc; | |
115 | unsigned char buf[2048]; | |
116 | struct sockaddr_ll sl; | |
117 | socklen_t salen = sizeof sl; | |
118 | ||
119 | cc = recvfrom(h->fd, &buf, sizeof(buf), 0, (struct sockaddr *) &sl, &salen); | |
120 | if(cc <= 0) | |
121 | { | |
122 | ERROR("recvfrom failed: %m"); | |
123 | return; | |
124 | } | |
125 | ||
126 | #ifdef PACKET_DEBUG | |
127 | printf("Receive Src ifindex %d %02x:%02x:%02x:%02x:%02x:%02x\n", | |
128 | sl.sll_ifindex, | |
129 | sl.sll_addr[0], sl.sll_addr[1], sl.sll_addr[2], | |
130 | sl.sll_addr[3], sl.sll_addr[4], sl.sll_addr[5]); | |
131 | ||
132 | dump_packet(buf, cc); | |
133 | #endif | |
134 | ||
135 | bridge_bpdu_rcv(sl.sll_ifindex, buf, cc); | |
136 | } | |
137 | ||
138 | /* Berkeley Packet filter code to filter out spanning tree packets. | |
139 | from tcpdump -s 1152 -dd stp | |
140 | */ | |
141 | static struct sock_filter stp_filter[] = { | |
142 | { 0x28, 0, 0, 0x0000000c }, | |
143 | { 0x25, 3, 0, 0x000005dc }, | |
144 | { 0x30, 0, 0, 0x0000000e }, | |
145 | { 0x15, 0, 1, 0x00000042 }, | |
146 | { 0x6, 0, 0, 0x00000480 }, | |
147 | { 0x6, 0, 0, 0x00000000 }, | |
148 | }; | |
149 | ||
150 | /* | |
151 | * Open up a raw packet socket to catch all 802.2 packets. | |
152 | * and install a packet filter to only see STP (SAP 42) | |
153 | * | |
154 | * Since any bridged devices are already in promiscious mode | |
155 | * no need to add multicast address. | |
156 | */ | |
157 | int packet_sock_init(void) | |
158 | { | |
159 | int s; | |
160 | struct sock_fprog prog = | |
161 | { | |
162 | .len = sizeof(stp_filter) / sizeof(stp_filter[0]), | |
163 | .filter = stp_filter, | |
164 | }; | |
165 | ||
166 | s = socket(PF_PACKET, SOCK_RAW, htons(ETH_P_802_2)); | |
167 | if(s < 0) | |
168 | { | |
169 | ERROR("socket failed: %m"); | |
170 | return -1; | |
171 | } | |
172 | ||
173 | if(setsockopt(s, SOL_SOCKET, SO_ATTACH_FILTER, &prog, sizeof(prog)) < 0) | |
174 | ERROR("setsockopt packet filter failed: %m"); | |
175 | else if(fcntl(s, F_SETFL, O_NONBLOCK) < 0) | |
176 | ERROR("fcntl set nonblock failed: %m"); | |
177 | else | |
178 | { | |
179 | packet_event.fd = s; | |
180 | packet_event.handler = packet_rcv; | |
181 | ||
182 | if(0 == add_epoll(&packet_event)) | |
183 | return 0; | |
184 | } | |
185 | ||
186 | close(s); | |
187 | return -1; | |
188 | } |