epan/dissectors/packet-socketcan.c

   1 /* packet-socketcan.c
   2  * Routines for disassembly of packets from SocketCAN
   3  * Felix Obenhuber <felix@obenhuber.de>
   4  *
   5  * $Id$
   6  *
   7  * Wireshark - Network traffic analyzer
   8  * By Gerald Combs <gerald@wireshark.org>
   9  * Copyright 1998 Gerald Combs
  10  *
  11  * This program is free software; you can redistribute it and/or
  12  * modify it under the terms of the GNU General Public License
  13  * as published by the Free Software Foundation; either version 2
  14  * of the License, or (at your option) any later version.
  15  *
  16  * This program is distributed in the hope that it will be useful,
  17  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  18  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  19  * GNU General Public License for more details.
  20  *
  21  * You should have received a copy of the GNU General Public License
  22  * along with this program; if not, write to the Free Software
  23  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  24  */
  25
  26 #include "config.h"
  27
  28 #include <glib.h>
  29
  30 #include <epan/packet.h>
  31 #include <prefs.h>
  32 #include "packet-sll.h"
  33
  34 /* controller area network (CAN) kernel definitions
  35  * These masks are usually defined within <linux/can.h> but are not
  36  * available on non-Linux platforms; that's the reason for the
  37  * redefinitions below
  38  *
  39  * special address description flags for the CAN_ID */
  40 #define CAN_EFF_FLAG 0x80000000U /* EFF/SFF is set in the MSB */
  41 #define CAN_RTR_FLAG 0x40000000U /* remote transmission request */
  42 #define CAN_ERR_FLAG 0x20000000U /* error frame */
  43 #define CAN_EFF_MASK 0x1FFFFFFFU /* extended frame format (EFF) */
  44
  45
  46 static int hf_can_len = -1;
  47 static int hf_can_ident = -1;
  48 static int hf_can_extflag = -1;
  49 static int hf_can_rtrflag = -1;
  50 static int hf_can_errflag = -1;
  51
  52 static gint ett_can = -1;
  53
  54 static int proto_can = -1;
  55
  56 static dissector_handle_t data_handle;
  57 static dissector_handle_t canopen_handle;
  58
  59 #define LINUX_CAN_STD   0
  60 #define LINUX_CAN_EXT   1
  61 #define LINUX_CAN_RTR   2
  62 #define LINUX_CAN_ERR   3
  63
  64 #define CAN_LEN_OFFSET  4
  65 #define CAN_DATA_OFFSET 8
  66
  67 typedef enum {
  68         CAN_DATA_DISSECTOR = 1,
  69         CAN_CANOPEN_DISSECTOR = 2
  70 } Dissector_Option;
  71
  72 static const enum_val_t can_high_level_protocol_dissector_options[] = {
  73         { "raw",        "Raw data (no further dissection)",     CAN_DATA_DISSECTOR },
  74         { "CANopen",    "CANopen protocol",                     CAN_CANOPEN_DISSECTOR },
  75         { NULL, NULL, 0 }
  76 };
  77
  78 static guint can_high_level_protocol_dissector = CAN_DATA_DISSECTOR;
  79
  80 static const value_string frame_type_vals[] =
  81 {
  82         { LINUX_CAN_STD, "STD" },
  83         { LINUX_CAN_EXT, "XTD" },
  84         { LINUX_CAN_RTR, "RTR" },
  85         { LINUX_CAN_ERR, "ERR" },
  86         { 0, NULL }
  87 };
  88
  89 static void
  90 dissect_socketcan(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
  91 {
  92         proto_tree *can_tree;
  93         proto_item *ti;
  94         guint8      frame_type;
  95         gint        frame_len;
  96         guint32     id;
  97
  98         col_set_str(pinfo->cinfo, COL_PROTOCOL, "CAN");
  99         col_clear(pinfo->cinfo,COL_INFO);
 100
 101         frame_len  = tvb_get_guint8( tvb, CAN_LEN_OFFSET);
 102         id         = tvb_get_ntohl(tvb, 0);
 103
 104         if (id & CAN_RTR_FLAG)
 105         {
 106                 frame_type = LINUX_CAN_RTR;
 107         }
 108         else if (id & CAN_ERR_FLAG)
 109         {
 110                 frame_type = LINUX_CAN_ERR;
 111         }
 112         else if (id & CAN_EFF_FLAG)
 113         {
 114                 frame_type = LINUX_CAN_EXT;
 115         }
 116         else
 117         {
 118                 frame_type = LINUX_CAN_STD;
 119         }
 120
 121         id &= CAN_EFF_MASK;
 122
 123         col_add_fstr(pinfo->cinfo, COL_INFO, "%s: 0x%08x",
 124                      val_to_str(frame_type, frame_type_vals, "Unknown (0x%02x)"), id);
 125         col_append_fstr(pinfo->cinfo, COL_INFO, "   %s",
 126                         tvb_bytes_to_str_punct(tvb, CAN_DATA_OFFSET, frame_len, ' '));
 127
 128         ti       = proto_tree_add_item(tree, proto_can, tvb, 0, -1, ENC_NA);
 129         can_tree = proto_item_add_subtree(ti, ett_can);
 130
 131         proto_tree_add_item(can_tree, hf_can_ident,   tvb, 0, 4, ENC_BIG_ENDIAN);
 132         proto_tree_add_item(can_tree, hf_can_extflag, tvb, 0, 4, ENC_BIG_ENDIAN);
 133         proto_tree_add_item(can_tree, hf_can_rtrflag, tvb, 0, 4, ENC_BIG_ENDIAN);
 134         proto_tree_add_item(can_tree, hf_can_errflag, tvb, 0, 4, ENC_BIG_ENDIAN);
 135
 136         proto_tree_add_item(can_tree, hf_can_len,     tvb, CAN_LEN_OFFSET, 1, ENC_BIG_ENDIAN);
 137
 138         switch (can_high_level_protocol_dissector)
 139         {
 140                 case CAN_DATA_DISSECTOR:
 141                         call_dissector(data_handle,
 142                                        tvb_new_subset(tvb, CAN_DATA_OFFSET, frame_len, frame_len),
 143                                        pinfo, tree);
 144                         break;
 145                 case CAN_CANOPEN_DISSECTOR:
 146                         /* XXX: The canopen dissector *redissects in a different manner* */
 147                         /*      the same header bytes dissected above.                   */
 148                         /*      What's the right way to handle SocketCan dissection ?    */
 149                         call_dissector(canopen_handle, tvb, pinfo, tree);
 150                         break;
 151         }
 152 }
 153
 154 void
 155 proto_register_socketcan(void)
 156 {
 157         static hf_register_info hf[] = {
 158                 {
 159                         &hf_can_ident,
 160                         {
 161                                 "Identifier", "can.id",
 162                                 FT_UINT32, BASE_HEX,
 163                                 NULL, CAN_EFF_MASK,
 164                                 NULL, HFILL
 165                         }
 166                 },
 167                 {
 168                         &hf_can_extflag,
 169                         {
 170                                 "Extended Flag", "can.flags.xtd",
 171                                 FT_BOOLEAN, 32,
 172                                 NULL, CAN_EFF_FLAG,
 173                                 NULL, HFILL
 174                         }
 175                 },
 176                 {
 177                         &hf_can_rtrflag,
 178                         {
 179                                 "Remote Transmission Request Flag", "can.flags.rtr",
 180                                 FT_BOOLEAN, 32,
 181                                 NULL, CAN_RTR_FLAG,
 182                                 NULL, HFILL
 183                         }
 184                 },
 185                 {
 186                         &hf_can_errflag,
 187                         {
 188                                 "Error Flag", "can.flags.err",
 189                                 FT_BOOLEAN, 32,
 190                                 NULL, CAN_ERR_FLAG,
 191                                 NULL, HFILL
 192                         }
 193                 },
 194                 {
 195                         &hf_can_len,
 196                         {
 197                                 "Frame-Length", "can.len",
 198                                 FT_UINT8, BASE_DEC,
 199                                 NULL, 0x0,
 200                                 NULL, HFILL
 201                         }
 202                 }
 203         };
 204
 205         /* Setup protocol subtree array */
 206         static gint *ett[] =
 207                 {
 208                         &ett_can
 209                 };
 210         module_t *can_module;
 211
 212         proto_can = proto_register_protocol(
 213                 "Controller Area Network",      /* name       */
 214                 "CAN",                          /* short name */
 215                 "can"                           /* abbrev     */
 216                 );
 217
 218         proto_register_field_array(proto_can, hf, array_length(hf));
 219         proto_register_subtree_array(ett, array_length(ett));
 220
 221         can_module = prefs_register_protocol(proto_can, NULL);
 222
 223         prefs_register_enum_preference(
 224                 can_module,
 225                 "protocol",
 226                 "Next level protocol",
 227                 "Next level protocol like CANopen etc.",
 228                 (gint *)&can_high_level_protocol_dissector,
 229                 can_high_level_protocol_dissector_options,
 230                 FALSE
 231                 );
 232 }
 233
 234 void
 235 proto_reg_handoff_socketcan(void)
 236 {
 237         dissector_handle_t can_handle;
 238
 239         can_handle = create_dissector_handle(dissect_socketcan, proto_can);
 240         dissector_add_uint("wtap_encap", WTAP_ENCAP_SOCKETCAN, can_handle);
 241         dissector_add_uint("sll.ltype", LINUX_SLL_P_CAN, can_handle);
 242
 243         canopen_handle = find_dissector("canopen");
 244         data_handle    = find_dissector("data");
 245 }