1 /* $NetBSD: pcap-can-linux.c,v 1.3 2015/03/31 21:39:42 christos Exp $ */
2
3 /*
4 * Copyright (c) 2009 Felix Obenhuber
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 *
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
16 * 3. The name of the author may not be used to endorse or promote
17 * products derived from this software without specific prior written
18 * permission.
19 *
20 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
21 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
22 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
23 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
24 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
25 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
26 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
27 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
28 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
29 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
30 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
31 *
32 * SocketCan sniffing API implementation for Linux platform
33 * By Felix Obenhuber <felix@obenhuber.de>
34 *
35 */
36
37 #include <sys/cdefs.h>
38 __RCSID("$NetBSD: pcap-can-linux.c,v 1.3 2015/03/31 21:39:42 christos Exp $");
39
40 #ifdef HAVE_CONFIG_H
41 #include "config.h"
42 #endif
43
44 #include "pcap-int.h"
45 #include "pcap-can-linux.h"
46
47 #ifdef NEED_STRERROR_H
48 #include "strerror.h"
49 #endif
50
51 #include <errno.h>
52 #include <stdlib.h>
53 #include <unistd.h>
54 #include <fcntl.h>
55 #include <string.h>
56 #include <sys/ioctl.h>
57 #include <sys/socket.h>
58 #include <net/if.h>
59 #include <arpa/inet.h>
60
61 #include <linux/can.h>
62 #include <linux/can/raw.h>
63
64 /* not yet defined anywhere */
65 #ifndef PF_CAN
66 #define PF_CAN 29
67 #endif
68 #ifndef AF_CAN
69 #define AF_CAN PF_CAN
70 #endif
71
72 /* forward declaration */
73 static int can_activate(pcap_t *);
74 static int can_read_linux(pcap_t *, int , pcap_handler , u_char *);
75 static int can_inject_linux(pcap_t *, const void *, size_t);
76 static int can_setfilter_linux(pcap_t *, struct bpf_program *);
77 static int can_setdirection_linux(pcap_t *, pcap_direction_t);
78 static int can_stats_linux(pcap_t *, struct pcap_stat *);
79
80 /*
81 * Private data for capturing on Linux CANbus devices.
82 */
83 struct pcap_can {
84 int ifindex; /* interface index of device we're bound to */
85 };
86
87 int
can_findalldevs(pcap_if_t ** devlistp,char * errbuf)88 can_findalldevs(pcap_if_t **devlistp, char *errbuf)
89 {
90 /*
91 * There are no platform-specific devices since each device
92 * exists as a regular network interface.
93 *
94 * XXX - true?
95 */
96 return 0;
97 }
98
99 pcap_t *
can_create(const char * device,char * ebuf,int * is_ours)100 can_create(const char *device, char *ebuf, int *is_ours)
101 {
102 const char *cp;
103 char *cpend;
104 long devnum;
105 pcap_t* p;
106
107 /* Does this look like a CANbus device? */
108 cp = strrchr(device, '/');
109 if (cp == NULL)
110 cp = device;
111 /* Does it begin with "can" or "vcan"? */
112 if (strncmp(cp, "can", 3) == 0) {
113 /* Begins with "can" */
114 cp += 3; /* skip past "can" */
115 } else if (strncmp(cp, "vcan", 4) == 0) {
116 /* Begins with "vcan" */
117 cp += 4;
118 } else {
119 /* Nope, doesn't begin with "can" or "vcan" */
120 *is_ours = 0;
121 return NULL;
122 }
123 /* Yes - is "can" or "vcan" followed by a number from 0? */
124 devnum = strtol(cp, &cpend, 10);
125 if (cpend == cp || *cpend != '\0') {
126 /* Not followed by a number. */
127 *is_ours = 0;
128 return NULL;
129 }
130 if (devnum < 0) {
131 /* Followed by a non-valid number. */
132 *is_ours = 0;
133 return NULL;
134 }
135
136 /* OK, it's probably ours. */
137 *is_ours = 1;
138
139 p = pcap_create_common(device, ebuf, sizeof (struct pcap_can));
140 if (p == NULL)
141 return (NULL);
142
143 p->activate_op = can_activate;
144 return (p);
145 }
146
147
148 static int
can_activate(pcap_t * handle)149 can_activate(pcap_t* handle)
150 {
151 struct pcap_can *handlep = handle->priv;
152 struct sockaddr_can addr;
153 struct ifreq ifr;
154
155 /* Initialize some components of the pcap structure. */
156 handle->bufsize = 24;
157 handle->offset = 8;
158 handle->linktype = DLT_CAN_SOCKETCAN;
159 handle->read_op = can_read_linux;
160 handle->inject_op = can_inject_linux;
161 handle->setfilter_op = can_setfilter_linux;
162 handle->setdirection_op = can_setdirection_linux;
163 handle->set_datalink_op = NULL;
164 handle->getnonblock_op = pcap_getnonblock_fd;
165 handle->setnonblock_op = pcap_setnonblock_fd;
166 handle->stats_op = can_stats_linux;
167
168 /* Create socket */
169 handle->fd = socket(PF_CAN, SOCK_RAW, CAN_RAW);
170 if (handle->fd < 0)
171 {
172 snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "Can't create raw socket %d:%s",
173 errno, strerror(errno));
174 return PCAP_ERROR;
175 }
176
177 /* get interface index */
178 memset(&ifr, 0, sizeof(ifr));
179 strlcpy(ifr.ifr_name, handle->opt.source, sizeof(ifr.ifr_name));
180 if (ioctl(handle->fd, SIOCGIFINDEX, &ifr) < 0)
181 {
182 snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
183 "Unable to get interface index: %s",
184 pcap_strerror(errno));
185 pcap_cleanup_live_common(handle);
186 return PCAP_ERROR;
187 }
188 handlep->ifindex = ifr.ifr_ifindex;
189
190 /* allocate butter */
191 handle->buffer = malloc(handle->bufsize);
192 if (!handle->buffer)
193 {
194 snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "Can't allocate dump buffer: %s",
195 pcap_strerror(errno));
196 pcap_cleanup_live_common(handle);
197 return PCAP_ERROR;
198 }
199
200 /* Bind to the socket */
201 addr.can_family = AF_CAN;
202 addr.can_ifindex = handlep->ifindex;
203 if( bind( handle->fd, (struct sockaddr*)&addr, sizeof(addr) ) < 0 )
204 {
205 snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "Can't attach to device %d %d:%s",
206 handlep->ifindex, errno, strerror(errno));
207 pcap_cleanup_live_common(handle);
208 return PCAP_ERROR;
209 }
210
211 if (handle->opt.rfmon)
212 {
213 /* Monitor mode doesn't apply to CAN devices. */
214 pcap_cleanup_live_common(handle);
215 return PCAP_ERROR_RFMON_NOTSUP;
216 }
217
218 handle->selectable_fd = handle->fd;
219 return 0;
220
221 }
222
223
224 static int
can_read_linux(pcap_t * handle,int max_packets,pcap_handler callback,u_char * user)225 can_read_linux(pcap_t *handle, int max_packets, pcap_handler callback, u_char *user)
226 {
227 struct msghdr msg;
228 struct pcap_pkthdr pkth;
229 struct iovec iv;
230 struct can_frame* cf;
231
232 iv.iov_base = &handle->buffer[handle->offset];
233 iv.iov_len = handle->snapshot;
234
235 memset(&msg, 0, sizeof(msg));
236 msg.msg_iov = &iv;
237 msg.msg_iovlen = 1;
238 msg.msg_control = handle->buffer;
239 msg.msg_controllen = handle->offset;
240
241 do
242 {
243 pkth.caplen = recvmsg(handle->fd, &msg, 0);
244 if (handle->break_loop)
245 {
246 handle->break_loop = 0;
247 return -2;
248 }
249 } while ((pkth.caplen == -1) && (errno == EINTR));
250
251 if (pkth.caplen == -1)
252 {
253 snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "Can't receive packet %d:%s",
254 errno, strerror(errno));
255 return -1;
256 }
257
258 /* adjust capture len according to frame len */
259 cf = (struct can_frame*)&handle->buffer[8];
260 pkth.caplen -= 8 - cf->can_dlc;
261 pkth.len = pkth.caplen;
262
263 cf->can_id = htonl( cf->can_id );
264
265 if( -1 == gettimeofday(&pkth.ts, NULL) )
266 {
267 snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "Can't get time of day %d:%s",
268 errno, strerror(errno));
269 return -1;
270 }
271
272 callback(user, &pkth, &handle->buffer[8]);
273
274 return 1;
275 }
276
277
278 static int
can_inject_linux(pcap_t * handle,const void * buf,size_t size)279 can_inject_linux(pcap_t *handle, const void *buf, size_t size)
280 {
281 /* not yet implemented */
282 snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "inject not supported on "
283 "can devices");
284 return (-1);
285 }
286
287
288 static int
can_stats_linux(pcap_t * handle,struct pcap_stat * stats)289 can_stats_linux(pcap_t *handle, struct pcap_stat *stats)
290 {
291 /* not yet implemented */
292 stats->ps_recv = 0; /* number of packets received */
293 stats->ps_drop = 0; /* number of packets dropped */
294 stats->ps_ifdrop = 0; /* drops by interface -- only supported on some platforms */
295 return 0;
296 }
297
298
299 static int
can_setfilter_linux(pcap_t * p,struct bpf_program * fp)300 can_setfilter_linux(pcap_t *p, struct bpf_program *fp)
301 {
302 /* not yet implemented */
303 return 0;
304 }
305
306
307 static int
can_setdirection_linux(pcap_t * p,pcap_direction_t d)308 can_setdirection_linux(pcap_t *p, pcap_direction_t d)
309 {
310 /* no support for PCAP_D_OUT */
311 if (d == PCAP_D_OUT)
312 {
313 snprintf(p->errbuf, sizeof(p->errbuf),
314 "Setting direction to PCAP_D_OUT is not supported on can");
315 return -1;
316 }
317
318 p->direction = d;
319
320 return 0;
321 }
322
323
324 /* eof */
325