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 pcap_t *
  76 can_create(const char *device, char *ebuf)
  77 {
  78         pcap_t* p;
  79
  80         p = pcap_create_common(device, ebuf);
  81         if (p == NULL)
  82                 return (NULL);
  83
  84         p->activate_op = can_activate;
  85         return (p);
  86 }
  87
  88
  89 static int
  90 can_activate(pcap_t* handle)
  91 {
  92         struct sockaddr_can addr;
  93         struct ifreq ifr;
  94
  95         /* Initialize some components of the pcap structure. */
  96         handle->bufsize = 24;
  97         handle->offset = 8;
  98         handle->linktype = DLT_CAN_SOCKETCAN;
  99         handle->read_op = can_read_linux;
 100         handle->inject_op = can_inject_linux;
 101         handle->setfilter_op = can_setfilter_linux;
 102         handle->setdirection_op = can_setdirection_linux;
 103         handle->set_datalink_op = NULL;
 104         handle->getnonblock_op = pcap_getnonblock_fd;
 105         handle->setnonblock_op = pcap_setnonblock_fd;
 106         handle->stats_op = can_stats_linux;
 107
 108         /* Create socket */
 109         handle->fd = socket(PF_CAN, SOCK_RAW, CAN_RAW);
 110         if (handle->fd < 0)
 111         {
 112                 snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "Can't create raw socket %d:%s",
 113                         errno, strerror(errno));
 114                 return PCAP_ERROR;
 115         }
 116
 117         /* get interface index */
 118         memset(&ifr, 0, sizeof(ifr));
 119         strncpy(ifr.ifr_name, handle->opt.source, sizeof(ifr.ifr_name));
 120         if (ioctl(handle->fd, SIOCGIFINDEX, &ifr) < 0)
 121         {
 122                 snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
 123                                 "Unable to get interface index: %s",
 124                         pcap_strerror(errno));
 125                 pcap_cleanup_live_common(handle);
 126                 return PCAP_ERROR;
 127         }
 128         handle->md.ifindex = ifr.ifr_ifindex;
 129
 130         /* allocate butter */
 131         handle->buffer = malloc(handle->bufsize);
 132         if (!handle->buffer)
 133         {
 134                 snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "Can't allocate dump buffer: %s",
 135                         pcap_strerror(errno));
 136                 pcap_cleanup_live_common(handle);
 137                 return PCAP_ERROR;
 138         }
 139
 140         /* Bind to the socket */
 141         addr.can_family = AF_CAN;
 142         addr.can_ifindex = handle->md.ifindex;
 143         if( bind( handle->fd, (struct sockaddr*)&addr, sizeof(addr) ) < 0  )
 144         {
 145                 snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "Can't attach to device %d %d:%s",
 146                         handle->md.ifindex, errno, strerror(errno));
 147                 pcap_cleanup_live_common(handle);
 148                 return PCAP_ERROR;
 149         }
 150
 151         if (handle->opt.rfmon)
 152         {
 153                 /* Monitor mode doesn't apply to CAN devices. */
 154                 pcap_cleanup_live_common(handle);
 155                 return PCAP_ERROR;
 156         }
 157
 158         handle->selectable_fd = handle->fd;
 159         return 0;
 160
 161 }
 162
 163
 164 static int
 165 can_read_linux(pcap_t *handle, int max_packets, pcap_handler callback, u_char *user)
 166 {
 167         struct msghdr msg;
 168         struct pcap_pkthdr pkth;
 169         struct iovec iv;
 170         struct can_frame* cf;
 171
 172         iv.iov_base = &handle->buffer[handle->offset];
 173         iv.iov_len = handle->snapshot;
 174
 175         memset(&msg, 0, sizeof(msg));
 176         msg.msg_iov = &iv;
 177         msg.msg_iovlen = 1;
 178         msg.msg_control = handle->buffer;
 179         msg.msg_controllen = handle->offset;
 180
 181         do
 182         {
 183                 pkth.caplen = recvmsg(handle->fd, &msg, 0);
 184                 if (handle->break_loop)
 185                 {
 186                         handle->break_loop = 0;
 187                         return -2;
 188                 }
 189         } while ((pkth.caplen == -1) && (errno == EINTR));
 190
 191         if (pkth.caplen < 0)
 192         {
 193                 snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "Can't receive packet %d:%s",
 194                         errno, strerror(errno));
 195                 return -1;
 196         }
 197
 198         /* adjust capture len according to frame len */
 199         cf = (struct can_frame*)&handle->buffer[8];
 200         pkth.caplen -= 8 - cf->can_dlc;
 201         pkth.len = pkth.caplen;
 202
 203         cf->can_id = htonl( cf->can_id );
 204
 205         if( -1 == gettimeofday(&pkth.ts, NULL) )
 206         {
 207                 snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "Can't get time of day %d:%s",
 208                         errno, strerror(errno));
 209                 return -1;
 210         }
 211
 212         callback(user, &pkth, &handle->buffer[8]);
 213
 214         return 1;
 215 }
 216
 217
 218 static int
 219 can_inject_linux(pcap_t *handle, const void *buf, size_t size)
 220 {
 221         /* not yet implemented */
 222         snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "inject not supported on "
 223                 "can devices");
 224         return (-1);
 225 }
 226
 227
 228 static int
 229 can_stats_linux(pcap_t *handle, struct pcap_stat *stats)
 230 {
 231         /* not yet implemented */
 232         stats->ps_recv = 0;                      /* number of packets received */
 233         stats->ps_drop = 0;                      /* number of packets dropped */
 234         stats->ps_ifdrop = 0;            /* drops by interface -- only supported on some platforms */
 235         return 0;
 236 }
 237
 238
 239 static int
 240 can_setfilter_linux(pcap_t *p, struct bpf_program *fp)
 241 {
 242         /* not yet implemented */
 243         return 0;
 244 }
 245
 246
 247 static int
 248 can_setdirection_linux(pcap_t *p, pcap_direction_t d)
 249 {
 250         /* no support for PCAP_D_OUT */
 251         if (d == PCAP_D_OUT)
 252         {
 253                 snprintf(p->errbuf, sizeof(p->errbuf),
 254                         "Setting direction to PCAP_D_OUT is not supported on can");
 255                 return -1;
 256         }
 257
 258         p->direction = d;
 259
 260         return 0;
 261 }
 262
 263
 264 /* eof */