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 (at) 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 strncpy(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 < 0) 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 */ 320
