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 #define CAN_CONTROL_SIZE 8
  43
  44 #ifdef NEED_STRERROR_H
  45 #include "strerror.h"
  46 #endif
  47
  48 #include <errno.h>
  49 #include <stdlib.h>
  50 #include <unistd.h>
  51 #include <fcntl.h>
  52 #include <string.h>
  53 #include <sys/ioctl.h>
  54 #include <sys/socket.h>
  55 #include <net/if.h>
  56 #include <arpa/inet.h>
  57
  58 #include <linux/can.h>
  59 #include <linux/can/raw.h>
  60
  61 /* not yet defined anywhere */
  62 #ifndef PF_CAN
  63 #define PF_CAN 29
  64 #endif
  65 #ifndef AF_CAN
  66 #define AF_CAN PF_CAN
  67 #endif
  68
  69 /* forward declaration */
  70 static int can_activate(pcap_t *);
  71 static int can_read_linux(pcap_t *, int , pcap_handler , u_char *);
  72 static int can_inject_linux(pcap_t *, const void *, size_t);
  73 static int can_setfilter_linux(pcap_t *, struct bpf_program *);
  74 static int can_setdirection_linux(pcap_t *, pcap_direction_t);
  75 static int can_stats_linux(pcap_t *, struct pcap_stat *);
  76
  77 /*
  78  * Private data for capturing on Linux CANbus devices.
  79  */
  80 struct pcap_can {
  81         int ifindex;            /* interface index of device we're bound to */
  82 };
  83
  84 int
  85 can_findalldevs(pcap_if_t **devlistp, char *errbuf)
  86 {
  87         /*
  88          * There are no platform-specific devices since each device
  89          * exists as a regular network interface.
  90          *
  91          * XXX - true?
  92          */
  93         return 0;
  94 }
  95
  96 pcap_t *
  97 can_create(const char *device, char *ebuf, int *is_ours)
  98 {
  99         const char *cp;
 100         char *cpend;
 101         long devnum;
 102         pcap_t* p;
 103
 104         /* Does this look like a CANbus device? */
 105         cp = strrchr(device, '/');
 106         if (cp == NULL)
 107                 cp = device;
 108         /* Does it begin with "can" or "vcan"? */
 109         if (strncmp(cp, "can", 3) == 0) {
 110                 /* Begins with "can" */
 111                 cp += 3;        /* skip past "can" */
 112         } else if (strncmp(cp, "vcan", 4) == 0) {
 113                 /* Begins with "vcan" */
 114                 cp += 4;
 115         } else {
 116                 /* Nope, doesn't begin with "can" or "vcan" */
 117                 *is_ours = 0;
 118                 return NULL;
 119         }
 120         /* Yes - is "can" or "vcan" followed by a number from 0? */
 121         devnum = strtol(cp, &cpend, 10);
 122         if (cpend == cp || *cpend != '\0') {
 123                 /* Not followed by a number. */
 124                 *is_ours = 0;
 125                 return NULL;
 126         }
 127         if (devnum < 0) {
 128                 /* Followed by a non-valid number. */
 129                 *is_ours = 0;
 130                 return NULL;
 131         }
 132
 133         /* OK, it's probably ours. */
 134         *is_ours = 1;
 135
 136         p = pcap_create_common(ebuf, sizeof (struct pcap_can));
 137         if (p == NULL)
 138                 return (NULL);
 139
 140         p->activate_op = can_activate;
 141         return (p);
 142 }
 143
 144
 145 static int
 146 can_activate(pcap_t* handle)
 147 {
 148         struct pcap_can *handlep = handle->priv;
 149         struct sockaddr_can addr;
 150         struct ifreq ifr;
 151
 152         /* Initialize some components of the pcap structure. */
 153         handle->bufsize = CAN_CONTROL_SIZE + 16;
 154         handle->linktype = DLT_CAN_SOCKETCAN_BIGENDIAN;
 155         handle->read_op = can_read_linux;
 156         handle->inject_op = can_inject_linux;
 157         handle->setfilter_op = can_setfilter_linux;
 158         handle->setdirection_op = can_setdirection_linux;
 159         handle->set_datalink_op = NULL;
 160         handle->getnonblock_op = pcap_getnonblock_fd;
 161         handle->setnonblock_op = pcap_setnonblock_fd;
 162         handle->stats_op = can_stats_linux;
 163
 164         /* Create socket */
 165         handle->fd = socket(PF_CAN, SOCK_RAW, CAN_RAW);
 166         if (handle->fd < 0)
 167         {
 168                 pcap_snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "Can't create raw socket %d:%s",
 169                         errno, strerror(errno));
 170                 return PCAP_ERROR;
 171         }
 172
 173         /* get interface index */
 174         memset(&ifr, 0, sizeof(ifr));
 175         strlcpy(ifr.ifr_name, handle->opt.device, sizeof(ifr.ifr_name));
 176         if (ioctl(handle->fd, SIOCGIFINDEX, &ifr) < 0)
 177         {
 178                 pcap_snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
 179                                 "Unable to get interface index: %s",
 180                         pcap_strerror(errno));
 181                 pcap_cleanup_live_common(handle);
 182                 return PCAP_ERROR;
 183         }
 184         handlep->ifindex = ifr.ifr_ifindex;
 185
 186         /* allocate butter */
 187         handle->buffer = malloc(handle->bufsize);
 188         if (!handle->buffer)
 189         {
 190                 pcap_snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "Can't allocate dump buffer: %s",
 191                         pcap_strerror(errno));
 192                 pcap_cleanup_live_common(handle);
 193                 return PCAP_ERROR;
 194         }
 195
 196         /* Bind to the socket */
 197         addr.can_family = AF_CAN;
 198         addr.can_ifindex = handlep->ifindex;
 199         if( bind( handle->fd, (struct sockaddr*)&addr, sizeof(addr) ) < 0  )
 200         {
 201                 pcap_snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "Can't attach to device %d %d:%s",
 202                         handlep->ifindex, errno, strerror(errno));
 203                 pcap_cleanup_live_common(handle);
 204                 return PCAP_ERROR;
 205         }
 206
 207         if (handle->opt.rfmon)
 208         {
 209                 /* Monitor mode doesn't apply to CAN devices. */
 210                 pcap_cleanup_live_common(handle);
 211                 return PCAP_ERROR_RFMON_NOTSUP;
 212         }
 213
 214         handle->selectable_fd = handle->fd;
 215         return 0;
 216
 217 }
 218
 219
 220 static int
 221 can_read_linux(pcap_t *handle, int max_packets, pcap_handler callback, u_char *user)
 222 {
 223         struct msghdr msg;
 224         struct pcap_pkthdr pkth;
 225         u_char *pktd;
 226         struct iovec iv;
 227         struct can_frame* cf;
 228         int len;
 229
 230         pktd = (u_char *)handle->buffer + CAN_CONTROL_SIZE;
 231         iv.iov_base = pktd;
 232         iv.iov_len = handle->snapshot;
 233
 234         memset(&msg, 0, sizeof(msg));
 235         msg.msg_iov = &iv;
 236         msg.msg_iovlen = 1;
 237         msg.msg_control = handle->buffer;
 238         msg.msg_controllen = CAN_CONTROL_SIZE;
 239
 240         do
 241         {
 242                 len = recvmsg(handle->fd, &msg, 0);
 243                 if (handle->break_loop)
 244                 {
 245                         handle->break_loop = 0;
 246                         return -2;
 247                 }
 248         } while ((len == -1) && (errno == EINTR));
 249
 250         if (len == -1)
 251         {
 252                 pcap_snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "Can't receive packet %d:%s",
 253                         errno, strerror(errno));
 254                 return -1;
 255         }
 256         pkth.caplen = (bpf_u_int32)len;
 257
 258         /* adjust capture len according to frame len */
 259         cf = (struct can_frame*)(void *)pktd;
 260         pkth.caplen -= CAN_CONTROL_SIZE - 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                 pcap_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, pktd);
 273
 274         return 1;
 275 }
 276
 277
 278 static int
 279 can_inject_linux(pcap_t *handle, const void *buf, size_t size)
 280 {
 281         /* not yet implemented */
 282         pcap_snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "inject not supported on "
 283                 "can devices");
 284         return (-1);
 285 }
 286
 287
 288 static int
 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
 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
 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                 pcap_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 */