The Tcpdump Group git mirrors - libpcap/blob - pcap-can-linux.c

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