epan/dissectors/packet-wsmp.c

   1 /* packet-wsmp.c
   2  * Routines for WAVE Short Message  dissection (WSMP)
   3  * Copyright 2013, Savari Networks (http://www.savarinetworks.com) (email: smooney@savarinetworks.com)
   4  *  Based on packet-wsmp.c implemented by
   5  *  Arada Systems (http://www.aradasystems.com) (email: siva@aradasystems.com)
   6  *
   7  * $Id$
   8  *
   9  * Wireshark - Network traffic analyzer
  10  * By Gerald Combs <gerald@wireshark.org>
  11  * Copyright 1998 Gerald Combs
  12  *
  13  * This program is free software; you can redistribute it and/or
  14  * modify it under the terms of the GNU General Public License
  15  * as published by the Free Software Foundation; either version 2
  16  * of the License, or (at your option) any later version.
  17  *
  18  * This program is distributed in the hope that it will be useful,
  19  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  20  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  21  * GNU General Public License for more details.
  22  *
  23  * You should have received a copy of the GNU General Public License
  24  * along with this program; if not, write to the Free Software
  25  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
  26  */
  27
  28 #include "config.h"
  29
  30 #include <glib.h>
  31
  32 #include <epan/packet.h>
  33 #include <epan/etypes.h>
  34
  35 #define WSMP       0x80
  36 #define WSMP_S     0x81
  37 #define WSMP_I     0x82
  38 #define CHANNUM    0x0F
  39 #define DATARATE   0x10
  40 #define TRANSMITPW 0x04
  41
  42 static const value_string wsmp_elemenid_names[] = {
  43     { 0x80, "WSMP" },
  44     { 0x81, "WSMP-S" },
  45     { 0x82, "WSMP-I" },
  46     { 0, NULL }
  47 };
  48
  49
  50 static dissector_handle_t data_handle;
  51
  52 /* Initialize the protocol and registered fields */
  53 static int proto_wsmp = -1;
  54 static int hf_wsmp_version = -1;
  55 static int hf_wsmp_psid = -1;
  56 static int hf_wsmp_rate = -1;
  57 static int hf_wsmp_channel = -1;
  58 static int hf_wsmp_txpower = -1;
  59 static int hf_wsmp_WAVEid = -1;
  60 static int hf_wsmp_wsmlength = -1;
  61 static int hf_wsmp_WSMP_S_data = -1;
  62
  63 /* Savari function to get the length of a psid based on the number of
  64     successive 1s in the most sig bits of the most sig octet. Taken
  65     from libwme
  66 */
  67 int wme_getpsidlen (guint8 *psid)
  68 {
  69     int length = 0;
  70     if ((psid[0] & 0xF0) == 0xF0) {
  71         length = 255;
  72     } else if ( (psid[0] & 0xE0) == 0xE0) {
  73         length = 4;
  74     } else if ( (psid[0] & 0xE0) == 0xC0) {
  75         length = 3;
  76     } else if ( (psid[0] & 0xC0) == 0x80) {
  77         length = 2;
  78     } else if ((psid[0] & 0x80) == 0x00) {
  79         length = 1;
  80     }
  81     return length;
  82 }
  83
  84 /* Initialize the subtree pointers */
  85 static gint ett_wsmp = -1;
  86 static gint ett_wsmdata = -1;
  87
  88 static void
  89 dissect_wsmp(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
  90 {
  91     /* Set up structures needed to add the protocol subtree and manage it */
  92     proto_item *ti, *wsmdata_item;
  93     proto_tree *wsmp_tree, *wsmdata_tree;
  94     tvbuff_t   *wsmdata_tvb;
  95     guint16     wsmlength, offset;
  96     guint32     psidLen, psid, supLen;
  97     guint8      elemenId, elemenLen, msb;
  98
  99     /* Make entries in Protocol column and Info column on summary display */
 100     col_set_str(pinfo->cinfo, COL_PROTOCOL, "WSMP");
 101
 102     col_set_str(pinfo->cinfo, COL_INFO, "WAVE Short Message Protocol IEEE P1609.3");
 103
 104     /* create display subtree for the protocol */
 105     ti = proto_tree_add_item(tree, proto_wsmp, tvb, 0, -1, ENC_NA);
 106
 107     wsmp_tree = proto_item_add_subtree(ti, ett_wsmp);
 108
 109     offset = 0;
 110     proto_tree_add_item(wsmp_tree,
 111                         hf_wsmp_version, tvb, offset, 1, ENC_BIG_ENDIAN);
 112     offset++;
 113
 114     psid    = tvb_get_guint8(tvb, offset);
 115     psidLen = (guint32)wme_getpsidlen((guint8*)&psid);
 116
 117
 118     if (psidLen == 2)
 119         psid = tvb_get_ntohs(tvb, offset);
 120     else if (psidLen == 3)
 121     {
 122         psid = tvb_get_ntohl(tvb, offset);
 123         psid = psid & 0x00FFFF; /* three bytes */
 124
 125     }
 126     else if (psidLen == 4)
 127         psid = tvb_get_ntohl(tvb, offset);
 128
 129     proto_tree_add_item(wsmp_tree,
 130                         hf_wsmp_psid, tvb, offset, psidLen, ENC_BIG_ENDIAN);
 131     offset += psidLen;
 132
 133
 134     elemenId = tvb_get_guint8(tvb, offset);
 135     while ((elemenId != WSMP) && (elemenId != WSMP_S) && (elemenId != WSMP_I))
 136     {
 137         offset++;
 138         if (elemenId == CHANNUM)
 139         {
 140             /* channel number */
 141             elemenLen = tvb_get_guint8(tvb, offset);
 142             offset++;
 143             proto_tree_add_item(wsmp_tree,
 144                                 hf_wsmp_channel, tvb, offset, elemenLen, ENC_BIG_ENDIAN);
 145             offset += elemenLen;
 146         }
 147         else if (elemenId == DATARATE)
 148         {
 149             /* Data rate  */
 150             elemenLen = tvb_get_guint8(tvb, offset);
 151             offset++;
 152             proto_tree_add_item(wsmp_tree,
 153                                 hf_wsmp_rate, tvb, offset, elemenLen, ENC_BIG_ENDIAN);
 154             offset += elemenLen;
 155         }
 156         else if (elemenId == TRANSMITPW)
 157         {
 158             /* Transmit power */
 159             elemenLen = tvb_get_guint8(tvb, offset);
 160             offset++;
 161             proto_tree_add_item(wsmp_tree,
 162                                 hf_wsmp_txpower, tvb, offset, elemenLen, ENC_BIG_ENDIAN);
 163             offset += elemenLen;
 164         }
 165         elemenId  = tvb_get_guint8(tvb, offset);
 166     }
 167
 168     proto_tree_add_item(wsmp_tree,
 169                         hf_wsmp_WAVEid, tvb, offset, 1, ENC_BIG_ENDIAN);
 170     offset++;
 171
 172     wsmlength = tvb_get_letohs( tvb, offset);
 173     proto_tree_add_item(wsmp_tree,
 174                         hf_wsmp_wsmlength, tvb, offset, 2, ENC_BIG_ENDIAN);
 175     offset += 2;
 176
 177     if (elemenId == WSMP_S)
 178     {
 179         msb    = 1;
 180         supLen = 0;
 181         while (msb)
 182         {
 183             msb = tvb_get_guint8(tvb, offset + supLen);
 184             msb = msb & 0x80;
 185             supLen++;
 186         }
 187         proto_tree_add_item(wsmp_tree,
 188                             hf_wsmp_WSMP_S_data, tvb, offset, supLen, ENC_BIG_ENDIAN);
 189         wsmlength -= supLen;
 190         offset    += supLen;
 191     }
 192
 193     wsmdata_item = proto_tree_add_text (wsmp_tree, tvb, offset, wsmlength,
 194                                         "Wave Short Message");
 195     wsmdata_tree = proto_item_add_subtree(wsmdata_item, ett_wsmdata);
 196
 197     wsmdata_tvb  = tvb_new_subset(tvb, offset, -1, wsmlength);
 198
 199     /* TODO: Branch on the application context and display accordingly
 200      * Default: call the data dissector
 201      */
 202     if (psid == 0xbff0)
 203     {
 204         call_dissector(data_handle, wsmdata_tvb, pinfo, wsmdata_tree);
 205     }
 206 }
 207
 208 void
 209 proto_register_wsmp(void)
 210 {
 211     /* Setup list of header fields  See Section 1.6.1 for details*/
 212     static hf_register_info hf[] = {
 213         { &hf_wsmp_version,
 214           { "Version",           "wsmp.version", FT_UINT8, BASE_DEC, NULL, 0x0,
 215             NULL, HFILL }},
 216
 217         { &hf_wsmp_psid,
 218           { "PSID",           "wsmp.psid", FT_UINT32, BASE_HEX, NULL, 0x0,
 219             NULL, HFILL }},
 220
 221         { &hf_wsmp_channel,
 222           { "Channel", "wsmp.channel", FT_UINT8, BASE_DEC, NULL, 0x0,
 223             NULL, HFILL }},
 224
 225         { &hf_wsmp_rate,
 226           { "Data Rate", "wsmp.rate", FT_UINT8, BASE_DEC, NULL, 0x0,
 227             NULL, HFILL }},
 228
 229         { &hf_wsmp_txpower,
 230           { "Transmit Power", "wsmp.txpower", FT_UINT8, BASE_DEC, NULL, 0x0,
 231             NULL, HFILL }},
 232
 233         { &hf_wsmp_WAVEid,
 234           { "WAVE element id", "wsmp.WAVEid", FT_UINT8, BASE_DEC, VALS(wsmp_elemenid_names), 0x0,
 235             NULL, HFILL }},
 236
 237         { &hf_wsmp_wsmlength,
 238           { "WSM Length", "wsmp.wsmlength", FT_UINT16, BASE_DEC, NULL, 0x0,
 239             NULL, HFILL }},
 240
 241         { &hf_wsmp_WSMP_S_data,
 242           { "WAVE Supplement Data", "wsmp.supplement", FT_UINT8, BASE_HEX, NULL, 0x0,
 243             NULL, HFILL }},
 244     };
 245
 246     /* Setup protocol subtree array */
 247     static gint *ett[] = {
 248         &ett_wsmp,
 249         &ett_wsmdata,
 250     };
 251
 252     /* Register the protocol name and description */
 253     proto_wsmp = proto_register_protocol("Wave Short Message Protocol(IEEE P1609.3)",
 254                                          "WSMP", "wsmp");
 255
 256     /* Required function calls to register the header fields and subtrees used */
 257     proto_register_field_array(proto_wsmp, hf, array_length(hf));
 258     proto_register_subtree_array(ett, array_length(ett));
 259 }
 260
 261 void
 262 proto_reg_handoff_wsmp(void)
 263 {
 264     dissector_handle_t wsmp_handle;
 265
 266     wsmp_handle = create_dissector_handle(dissect_wsmp, proto_wsmp);
 267     dissector_add_uint("ethertype", ETHERTYPE_WSMP, wsmp_handle);
 268     data_handle = find_dissector("data");
 269     return;
 270 }