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1 office 1 /*
2 * Copyright (c) 2009 Felix Obenhuber
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 *
9 * 1. Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
14 * 3. The name of the author may not be used to endorse or promote
15 * products derived from this software without specific prior written
16 * permission.
17 *
18 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
19 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
20 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
21 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
22 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
23 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
24 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
25 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
26 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
27 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
28 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
29 *
30 * SocketCan sniffing API implementation for Linux platform
31 * By Felix Obenhuber <felix@obenhuber.de>
32 *
33 */
34  
35 #ifdef HAVE_CONFIG_H
36 #include "config.h"
37 #endif
38  
39 #include "pcap-int.h"
40 #include "pcap-can-linux.h"
41  
42 #ifdef NEED_STRERROR_H
43 #include "strerror.h"
44 #endif
45  
46 #include <errno.h>
47 #include <stdlib.h>
48 #include <unistd.h>
49 #include <fcntl.h>
50 #include <string.h>
51 #include <sys/ioctl.h>
52 #include <sys/socket.h>
53 #include <net/if.h>
54 #include <arpa/inet.h>
55  
56 #include <linux/can.h>
57 #include <linux/can/raw.h>
58  
59 /* not yet defined anywhere */
60 #ifndef PF_CAN
61 #define PF_CAN 29
62 #endif
63 #ifndef AF_CAN
64 #define AF_CAN PF_CAN
65 #endif
66  
67 /* forward declaration */
68 static int can_activate(pcap_t *);
69 static int can_read_linux(pcap_t *, int , pcap_handler , u_char *);
70 static int can_inject_linux(pcap_t *, const void *, size_t);
71 static int can_setfilter_linux(pcap_t *, struct bpf_program *);
72 static int can_setdirection_linux(pcap_t *, pcap_direction_t);
73 static int can_stats_linux(pcap_t *, struct pcap_stat *);
74  
75 /*
76 * Private data for capturing on Linux CANbus devices.
77 */
78 struct pcap_can {
79 int ifindex; /* interface index of device we're bound to */
80 };
81  
82 int
83 can_findalldevs(pcap_if_t **devlistp, char *errbuf)
84 {
85 /*
86 * There are no platform-specific devices since each device
87 * exists as a regular network interface.
88 *
89 * XXX - true?
90 */
91 return 0;
92 }
93  
94 pcap_t *
95 can_create(const char *device, char *ebuf, int *is_ours)
96 {
97 const char *cp;
98 char *cpend;
99 long devnum;
100 pcap_t* p;
101  
102 /* Does this look like a CANbus device? */
103 cp = strrchr(device, '/');
104 if (cp == NULL)
105 cp = device;
106 /* Does it begin with "can" or "vcan"? */
107 if (strncmp(cp, "can", 3) == 0) {
108 /* Begins with "can" */
109 cp += 3; /* skip past "can" */
110 } else if (strncmp(cp, "vcan", 4) == 0) {
111 /* Begins with "vcan" */
112 cp += 4;
113 } else {
114 /* Nope, doesn't begin with "can" or "vcan" */
115 *is_ours = 0;
116 return NULL;
117 }
118 /* Yes - is "can" or "vcan" followed by a number from 0? */
119 devnum = strtol(cp, &cpend, 10);
120 if (cpend == cp || *cpend != '\0') {
121 /* Not followed by a number. */
122 *is_ours = 0;
123 return NULL;
124 }
125 if (devnum < 0) {
126 /* Followed by a non-valid number. */
127 *is_ours = 0;
128 return NULL;
129 }
130  
131 /* OK, it's probably ours. */
132 *is_ours = 1;
133  
134 p = pcap_create_common(device, ebuf, sizeof (struct pcap_can));
135 if (p == NULL)
136 return (NULL);
137  
138 p->activate_op = can_activate;
139 return (p);
140 }
141  
142  
143 static int
144 can_activate(pcap_t* handle)
145 {
146 struct pcap_can *handlep = handle->priv;
147 struct sockaddr_can addr;
148 struct ifreq ifr;
149  
150 /* Initialize some components of the pcap structure. */
151 handle->bufsize = 24;
152 handle->offset = 8;
153 handle->linktype = DLT_CAN_SOCKETCAN;
154 handle->read_op = can_read_linux;
155 handle->inject_op = can_inject_linux;
156 handle->setfilter_op = can_setfilter_linux;
157 handle->setdirection_op = can_setdirection_linux;
158 handle->set_datalink_op = NULL;
159 handle->getnonblock_op = pcap_getnonblock_fd;
160 handle->setnonblock_op = pcap_setnonblock_fd;
161 handle->stats_op = can_stats_linux;
162  
163 /* Create socket */
164 handle->fd = socket(PF_CAN, SOCK_RAW, CAN_RAW);
165 if (handle->fd < 0)
166 {
167 snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "Can't create raw socket %d:%s",
168 errno, strerror(errno));
169 return PCAP_ERROR;
170 }
171  
172 /* get interface index */
173 memset(&ifr, 0, sizeof(ifr));
174 strlcpy(ifr.ifr_name, handle->opt.source, sizeof(ifr.ifr_name));
175 if (ioctl(handle->fd, SIOCGIFINDEX, &ifr) < 0)
176 {
177 snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
178 "Unable to get interface index: %s",
179 pcap_strerror(errno));
180 pcap_cleanup_live_common(handle);
181 return PCAP_ERROR;
182 }
183 handlep->ifindex = ifr.ifr_ifindex;
184  
185 /* allocate butter */
186 handle->buffer = malloc(handle->bufsize);
187 if (!handle->buffer)
188 {
189 snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "Can't allocate dump buffer: %s",
190 pcap_strerror(errno));
191 pcap_cleanup_live_common(handle);
192 return PCAP_ERROR;
193 }
194  
195 /* Bind to the socket */
196 addr.can_family = AF_CAN;
197 addr.can_ifindex = handlep->ifindex;
198 if( bind( handle->fd, (struct sockaddr*)&addr, sizeof(addr) ) < 0 )
199 {
200 snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "Can't attach to device %d %d:%s",
201 handlep->ifindex, errno, strerror(errno));
202 pcap_cleanup_live_common(handle);
203 return PCAP_ERROR;
204 }
205  
206 if (handle->opt.rfmon)
207 {
208 /* Monitor mode doesn't apply to CAN devices. */
209 pcap_cleanup_live_common(handle);
210 return PCAP_ERROR_RFMON_NOTSUP;
211 }
212  
213 handle->selectable_fd = handle->fd;
214 return 0;
215  
216 }
217  
218  
219 static int
220 can_read_linux(pcap_t *handle, int max_packets, pcap_handler callback, u_char *user)
221 {
222 struct msghdr msg;
223 struct pcap_pkthdr pkth;
224 struct iovec iv;
225 struct can_frame* cf;
226  
227 iv.iov_base = &handle->buffer[handle->offset];
228 iv.iov_len = handle->snapshot;
229  
230 memset(&msg, 0, sizeof(msg));
231 msg.msg_iov = &iv;
232 msg.msg_iovlen = 1;
233 msg.msg_control = handle->buffer;
234 msg.msg_controllen = handle->offset;
235  
236 do
237 {
238 pkth.caplen = recvmsg(handle->fd, &msg, 0);
239 if (handle->break_loop)
240 {
241 handle->break_loop = 0;
242 return -2;
243 }
244 } while ((pkth.caplen == -1) && (errno == EINTR));
245  
246 if (pkth.caplen == -1)
247 {
248 snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "Can't receive packet %d:%s",
249 errno, strerror(errno));
250 return -1;
251 }
252  
253 /* adjust capture len according to frame len */
254 cf = (struct can_frame*)&handle->buffer[8];
255 pkth.caplen -= 8 - cf->can_dlc;
256 pkth.len = pkth.caplen;
257  
258 cf->can_id = htonl( cf->can_id );
259  
260 if( -1 == gettimeofday(&pkth.ts, NULL) )
261 {
262 snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "Can't get time of day %d:%s",
263 errno, strerror(errno));
264 return -1;
265 }
266  
267 callback(user, &pkth, &handle->buffer[8]);
268  
269 return 1;
270 }
271  
272  
273 static int
274 can_inject_linux(pcap_t *handle, const void *buf, size_t size)
275 {
276 /* not yet implemented */
277 snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "inject not supported on "
278 "can devices");
279 return (-1);
280 }
281  
282  
283 static int
284 can_stats_linux(pcap_t *handle, struct pcap_stat *stats)
285 {
286 /* not yet implemented */
287 stats->ps_recv = 0; /* number of packets received */
288 stats->ps_drop = 0; /* number of packets dropped */
289 stats->ps_ifdrop = 0; /* drops by interface -- only supported on some platforms */
290 return 0;
291 }
292  
293  
294 static int
295 can_setfilter_linux(pcap_t *p, struct bpf_program *fp)
296 {
297 /* not yet implemented */
298 return 0;
299 }
300  
301  
302 static int
303 can_setdirection_linux(pcap_t *p, pcap_direction_t d)
304 {
305 /* no support for PCAP_D_OUT */
306 if (d == PCAP_D_OUT)
307 {
308 snprintf(p->errbuf, sizeof(p->errbuf),
309 "Setting direction to PCAP_D_OUT is not supported on can");
310 return -1;
311 }
312  
313 p->direction = d;
314  
315 return 0;
316 }
317  
318  
319 /* eof */