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., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
  24  */
  25
  26 #ifdef HAVE_CONFIG_H
  27 # include "config.h"
  28 #endif
  29
  30 #include <glib.h>
  31 #include <epan/packet.h>
  32
  33 /* controller area network (CAN) kernel definitions
  34  * This maskare usualy defined within <linux/can.h> but not
  35  * available on non-Linux platforms - that the reason for the
  36  * redefinition right here
  37  *
  38  * special address description flags for the CAN_ID */
  39 #define CAN_EFF_FLAG 0x80000000U /* EFF/SFF is set in the MSB */
  40 #define CAN_RTR_FLAG 0x40000000U /* remote transmission request */
  41 #define CAN_ERR_FLAG 0x20000000U /* error frame */
  42 #define CAN_EFF_MASK 0x1FFFFFFFU /* extended frame format (EFF) */
  43
  44
  45 static int hf_can_len = -1;
  46 static int hf_can_ident = -1;
  47 static int hf_can_extflag = -1;
  48 static int hf_can_rtrflag = -1;
  49 static int hf_can_errflag = -1;
  50
  51 static gint ett_can = -1;
  52
  53 static int proto_can = -1;
  54
  55 static dissector_handle_t data_handle;
  56
  57 #define LINUX_CAN_STD 0
  58 #define LINUX_CAN_EXT 1
  59 #define LINUX_CAN_RTR 2
  60 #define LINUX_CAN_ERR 3
  61
  62 #define CAN_LEN_OFFSET 4
  63 #define CAN_DATA_OFFSET 8
  64
  65 static const value_string frame_type_vals[] =
  66 {
  67         { LINUX_CAN_STD, "STD" },
  68         { LINUX_CAN_EXT, "XTD" },
  69         { LINUX_CAN_RTR, "RTR" },
  70         { LINUX_CAN_ERR, "ERR" },
  71         { 0, NULL }
  72 };
  73
  74 static void
  75 dissect_socketcan(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
  76 {
  77         guint8 frame_type = LINUX_CAN_STD;
  78         tvbuff_t *next_tvb;
  79         guint8 frame_len = tvb_get_guint8( tvb, CAN_LEN_OFFSET );
  80         guint32 id = tvb_get_ntohl(tvb, 0);
  81
  82         if( id & CAN_RTR_FLAG )
  83         {
  84                 frame_type = LINUX_CAN_RTR;
  85         }
  86         else if ( id & CAN_ERR_FLAG )
  87         {
  88                 frame_type = LINUX_CAN_ERR;
  89         }
  90         else if( id & CAN_EFF_FLAG )
  91         {
  92                 frame_type = LINUX_CAN_EXT;
  93         }
  94
  95         id &= CAN_EFF_MASK;
  96
  97         col_set_str(pinfo->cinfo, COL_PROTOCOL, "CAN");
  98         col_clear(pinfo->cinfo,COL_INFO);
  99         col_add_fstr(pinfo->cinfo, COL_INFO, "%s: 0x%08x", val_to_str(frame_type, frame_type_vals, "Unknown (0x%02x)"), id );
 100         col_append_fstr(pinfo->cinfo, COL_INFO, "   %s", tvb_bytes_to_str_punct(tvb, CAN_DATA_OFFSET, frame_len, ' '));
 101
 102         if (tree)
 103         {
 104                 proto_tree *can_tree = NULL;
 105                 proto_item *ti = proto_tree_add_item(tree, proto_can, tvb, 0, 1 , FALSE );
 106                 can_tree = proto_item_add_subtree(ti, ett_can);
 107
 108                 proto_tree_add_item(can_tree, hf_can_ident, tvb, 0, 4, FALSE );
 109                 proto_tree_add_item(can_tree, hf_can_extflag, tvb, 0, 4, FALSE );
 110                 proto_tree_add_item(can_tree, hf_can_rtrflag, tvb, 0, 4, FALSE );
 111                 proto_tree_add_item(can_tree, hf_can_errflag, tvb, 0, 4, FALSE );
 112                 proto_tree_add_item(can_tree, hf_can_len, tvb, CAN_LEN_OFFSET, 1, FALSE );
 113
 114                 next_tvb =  tvb_new_subset(tvb, CAN_DATA_OFFSET, tvb_get_guint8(tvb, CAN_LEN_OFFSET), 8 );
 115                 call_dissector(data_handle, next_tvb, pinfo, tree );
 116         }
 117 }
 118
 119
 120 void
 121 proto_register_socketcan(void)
 122 {
 123         static hf_register_info hf[] =
 124         {
 125                 {
 126                         &hf_can_ident,
 127                         {
 128                                 "Identifier", "can.id",
 129                                         FT_UINT32, BASE_HEX,
 130                                         NULL, CAN_EFF_MASK,
 131                                         NULL, HFILL
 132                         }
 133                 },
 134                 {
 135                         &hf_can_extflag,
 136                         {
 137                                 "Extended Flag", "can.flags.xtd",
 138                                         FT_BOOLEAN, 32,
 139                                         NULL, CAN_EFF_FLAG,
 140                                         NULL, HFILL
 141                         }
 142                 },
 143                 {
 144                         &hf_can_rtrflag,
 145                         {
 146                                 "Remote Transmission Request Flag", "can.flags.rtr",
 147                                         FT_BOOLEAN, 32,
 148                                         NULL, CAN_RTR_FLAG,
 149                                         NULL, HFILL
 150                         }
 151                 },
 152                 {
 153                         &hf_can_errflag,
 154                         {
 155                                 "Error Flag", "can.flags.err",
 156                                         FT_BOOLEAN, 32,
 157                                         NULL, CAN_ERR_FLAG,
 158                                         NULL, HFILL
 159                         }
 160                 },
 161                 {
 162                         &hf_can_len,
 163                         {
 164                                 "Frame-Length", "can.len",
 165                                         FT_UINT8, BASE_DEC,
 166                                         NULL, 0x0,
 167                                         NULL, HFILL
 168                         }
 169                 }
 170         };
 171
 172         /* Setup protocol subtree array */
 173         static gint *ett[] =
 174         {
 175                 &ett_can
 176         };
 177
 178         proto_can = proto_register_protocol (
 179                 "Controller Area Network",/* name       */
 180                 "CAN",                                   /* short name */
 181                 "can"                                    /* abbrev     */
 182                 );
 183
 184         proto_register_field_array(proto_can, hf, array_length(hf));
 185         proto_register_subtree_array(ett, array_length(ett));
 186 }
 187
 188
 189 void
 190 proto_reg_handoff_socketcan(void)
 191 {
 192         dissector_handle_t can_handle;
 193
 194         data_handle = find_dissector("data");
 195
 196         can_handle = create_dissector_handle(dissect_socketcan, proto_can);
 197         dissector_add("wtap_encap", WTAP_ENCAP_SOCKETCAN, can_handle);
 198 }
 199
 200
 201 /* eof */