pcap-can-linux.c revision 267654
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 */ 68static int can_activate(pcap_t *); 69static int can_read_linux(pcap_t *, int , pcap_handler , u_char *); 70static int can_inject_linux(pcap_t *, const void *, size_t); 71static int can_setfilter_linux(pcap_t *, struct bpf_program *); 72static int can_setdirection_linux(pcap_t *, pcap_direction_t); 73static int can_stats_linux(pcap_t *, struct pcap_stat *); 74 75int 76can_findalldevs(pcap_if_t **devlistp, char *errbuf) 77{ 78 /* 79 * There are no platform-specific devices since each device 80 * exists as a regular network interface. 81 * 82 * XXX - true? 83 */ 84 return 0; 85} 86 87pcap_t * 88can_create(const char *device, char *ebuf, int *is_ours) 89{ 90 const char *cp; 91 char *cpend; 92 long devnum; 93 pcap_t* p; 94 95 /* Does this look like a CANbus device? */ 96 cp = strrchr(device, '/'); 97 if (cp == NULL) 98 cp = device; 99 /* Does it begin with "can" or "vcan"? */ 100 if (strncmp(cp, "can", 3) == 0) { 101 /* Begins with "can" */ 102 cp += 3; /* skip past "can" */ 103 } else if (strncmp(cp, "vcan", 4) == 0) { 104 /* Begins with "vcan" */ 105 cp += 4; 106 } else { 107 /* Nope, doesn't begin with "can" or "vcan" */ 108 *is_ours = 0; 109 return NULL; 110 } 111 /* Yes - is "can" or "vcan" followed by a number from 0? */ 112 devnum = strtol(cp, &cpend, 10); 113 if (cpend == cp || *cpend != '\0') { 114 /* Not followed by a number. */ 115 *is_ours = 0; 116 return NULL; 117 } 118 if (devnum < 0) { 119 /* Followed by a non-valid number. */ 120 *is_ours = 0; 121 return NULL; 122 } 123 124 /* OK, it's probably ours. */ 125 *is_ours = 1; 126 127 p = pcap_create_common(device, ebuf); 128 if (p == NULL) 129 return (NULL); 130 131 p->activate_op = can_activate; 132 return (p); 133} 134 135 136static int 137can_activate(pcap_t* handle) 138{ 139 struct sockaddr_can addr; 140 struct ifreq ifr; 141 142 /* Initialize some components of the pcap structure. */ 143 handle->bufsize = 24; 144 handle->offset = 8; 145 handle->linktype = DLT_CAN_SOCKETCAN; 146 handle->read_op = can_read_linux; 147 handle->inject_op = can_inject_linux; 148 handle->setfilter_op = can_setfilter_linux; 149 handle->setdirection_op = can_setdirection_linux; 150 handle->set_datalink_op = NULL; 151 handle->getnonblock_op = pcap_getnonblock_fd; 152 handle->setnonblock_op = pcap_setnonblock_fd; 153 handle->stats_op = can_stats_linux; 154 155 /* Create socket */ 156 handle->fd = socket(PF_CAN, SOCK_RAW, CAN_RAW); 157 if (handle->fd < 0) 158 { 159 snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "Can't create raw socket %d:%s", 160 errno, strerror(errno)); 161 return PCAP_ERROR; 162 } 163 164 /* get interface index */ 165 memset(&ifr, 0, sizeof(ifr)); 166 strncpy(ifr.ifr_name, handle->opt.source, sizeof(ifr.ifr_name)); 167 if (ioctl(handle->fd, SIOCGIFINDEX, &ifr) < 0) 168 { 169 snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, 170 "Unable to get interface index: %s", 171 pcap_strerror(errno)); 172 pcap_cleanup_live_common(handle); 173 return PCAP_ERROR; 174 } 175 handle->md.ifindex = ifr.ifr_ifindex; 176 177 /* allocate butter */ 178 handle->buffer = malloc(handle->bufsize); 179 if (!handle->buffer) 180 { 181 snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "Can't allocate dump buffer: %s", 182 pcap_strerror(errno)); 183 pcap_cleanup_live_common(handle); 184 return PCAP_ERROR; 185 } 186 187 /* Bind to the socket */ 188 addr.can_family = AF_CAN; 189 addr.can_ifindex = handle->md.ifindex; 190 if( bind( handle->fd, (struct sockaddr*)&addr, sizeof(addr) ) < 0 ) 191 { 192 snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "Can't attach to device %d %d:%s", 193 handle->md.ifindex, errno, strerror(errno)); 194 pcap_cleanup_live_common(handle); 195 return PCAP_ERROR; 196 } 197 198 if (handle->opt.rfmon) 199 { 200 /* Monitor mode doesn't apply to CAN devices. */ 201 pcap_cleanup_live_common(handle); 202 return PCAP_ERROR; 203 } 204 205 handle->selectable_fd = handle->fd; 206 return 0; 207 208} 209 210 211static int 212can_read_linux(pcap_t *handle, int max_packets, pcap_handler callback, u_char *user) 213{ 214 struct msghdr msg; 215 struct pcap_pkthdr pkth; 216 struct iovec iv; 217 struct can_frame* cf; 218 219 iv.iov_base = &handle->buffer[handle->offset]; 220 iv.iov_len = handle->snapshot; 221 222 memset(&msg, 0, sizeof(msg)); 223 msg.msg_iov = &iv; 224 msg.msg_iovlen = 1; 225 msg.msg_control = handle->buffer; 226 msg.msg_controllen = handle->offset; 227 228 do 229 { 230 pkth.caplen = recvmsg(handle->fd, &msg, 0); 231 if (handle->break_loop) 232 { 233 handle->break_loop = 0; 234 return -2; 235 } 236 } while ((pkth.caplen == -1) && (errno == EINTR)); 237 238 if (pkth.caplen < 0) 239 { 240 snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "Can't receive packet %d:%s", 241 errno, strerror(errno)); 242 return -1; 243 } 244 245 /* adjust capture len according to frame len */ 246 cf = (struct can_frame*)&handle->buffer[8]; 247 pkth.caplen -= 8 - cf->can_dlc; 248 pkth.len = pkth.caplen; 249 250 cf->can_id = htonl( cf->can_id ); 251 252 if( -1 == gettimeofday(&pkth.ts, NULL) ) 253 { 254 snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "Can't get time of day %d:%s", 255 errno, strerror(errno)); 256 return -1; 257 } 258 259 callback(user, &pkth, &handle->buffer[8]); 260 261 return 1; 262} 263 264 265static int 266can_inject_linux(pcap_t *handle, const void *buf, size_t size) 267{ 268 /* not yet implemented */ 269 snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "inject not supported on " 270 "can devices"); 271 return (-1); 272} 273 274 275static int 276can_stats_linux(pcap_t *handle, struct pcap_stat *stats) 277{ 278 /* not yet implemented */ 279 stats->ps_recv = 0; /* number of packets received */ 280 stats->ps_drop = 0; /* number of packets dropped */ 281 stats->ps_ifdrop = 0; /* drops by interface -- only supported on some platforms */ 282 return 0; 283} 284 285 286static int 287can_setfilter_linux(pcap_t *p, struct bpf_program *fp) 288{ 289 /* not yet implemented */ 290 return 0; 291} 292 293 294static int 295can_setdirection_linux(pcap_t *p, pcap_direction_t d) 296{ 297 /* no support for PCAP_D_OUT */ 298 if (d == PCAP_D_OUT) 299 { 300 snprintf(p->errbuf, sizeof(p->errbuf), 301 "Setting direction to PCAP_D_OUT is not supported on can"); 302 return -1; 303 } 304 305 p->direction = d; 306 307 return 0; 308} 309 310 311/* eof */ 312