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;
  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
 136 static int
 137 can_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
 211 static int
 212 can_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
 265 static int
 266 can_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
 275 static int
 276 can_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
 286 static int
 287 can_setfilter_linux(pcap_t *p, struct bpf_program *fp)
 288 {
 289         /* not yet implemented */
 290         return 0;
 291 }
 292
 293
 294 static int
 295 can_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 */