packet-sdp.c

   1 /* packet-sdp.c
   2  * Routines for SDP packet disassembly (RFC 2327)
   3  *
   4  * Jason Lango <jal@netapp.com>
   5  * Liberally copied from packet-http.c, by Guy Harris <guy@alum.mit.edu>
   6  *
   7  * $Id: packet-sdp.c,v 1.21 2001/12/10 00:25:34 guy Exp $
   8  *
   9  * Ethereal - Network traffic analyzer
  10  * By Gerald Combs <gerald@ethereal.com>
  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., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
  26  */
  27
  28 #include "config.h"
  29
  30 #ifdef HAVE_SYS_TYPES_H
  31 #include <sys/types.h>
  32 #endif
  33
  34 #include <string.h>
  35 #include <ctype.h>
  36
  37 #include <glib.h>
  38 #include "packet.h"
  39 #include "strutil.h"
  40
  41 static int proto_sdp = -1;
  42
  43 static int ett_sdp = -1;
  44
  45 static void
  46 dissect_sdp(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
  47 {
  48         proto_tree      *sdp_tree;
  49         proto_item      *ti;
  50         gint            offset = 0;
  51         const u_char    *line;
  52         gint            next_offset;
  53         int             linelen;
  54         u_char          section;
  55         u_char          type;
  56         const u_char    *value;
  57         int             valuelen;
  58         const char      *typename;
  59         int             datalen;
  60
  61         /*
  62          * As RFC 2327 says, "SDP is purely a format for session
  63          * description - it does not incorporate a transport protocol,
  64          * and is intended to use different transport protocols as
  65          * appropriate including the Session Announcement Protocol,
  66          * Session Initiation Protocol, Real-Time Streaming Protocol,
  67          * electronic mail using the MIME extensions, and the
  68          * Hypertext Transport Protocol."
  69          *
  70          * We therefore don't set the protocol or info columns;
  71          * instead, we append to them, so that we don't erase
  72          * what the protocol inside which the SDP stuff resides
  73          * put there.
  74          */
  75         if (check_col(pinfo->cinfo, COL_PROTOCOL))
  76                 col_append_str(pinfo->cinfo, COL_PROTOCOL, "/SDP");
  77
  78         if (check_col(pinfo->cinfo, COL_INFO)) {
  79                 /* XXX: Needs description. */
  80                 col_append_str(pinfo->cinfo, COL_INFO, ", with session description");
  81         }
  82
  83         if (!tree)
  84                 return;
  85
  86         ti = proto_tree_add_item(tree, proto_sdp, tvb, offset,
  87             tvb_length_remaining(tvb, offset), FALSE);
  88         sdp_tree = proto_item_add_subtree(ti, ett_sdp);
  89
  90         /*
  91          * Show the SDP message a line at a time.
  92          */
  93         section = 0;
  94         while (tvb_offset_exists(tvb, offset)) {
  95                 /*
  96                  * Find the end of the line.
  97                  */
  98                 linelen = tvb_find_line_end_unquoted(tvb, offset, -1,
  99                     &next_offset);
 100
 101                 /*
 102                  * Line must contain at least e.g. "v=".
 103                  */
 104                 if (linelen < 2)
 105                         break;
 106
 107                 line = tvb_get_ptr(tvb, offset, next_offset - offset);
 108                 type = line[0];
 109                 if (line[1] != '=') {
 110                         proto_tree_add_text(sdp_tree, tvb, offset,
 111                             next_offset - offset,
 112                             "Invalid line: %s",
 113                             tvb_format_text(tvb, offset, next_offset - offset));
 114                         offset = next_offset;
 115                         continue;
 116                 }
 117                 value = line + 2;
 118                 valuelen = linelen - 2;
 119
 120                 /*
 121                  * Attributes.
 122                  */
 123                 switch (type) {
 124                 case 'v':
 125                         section = 'v';
 126                         typename = "Session Description, version";
 127                         break;
 128                 case 'o':
 129                         typename = "Owner/Creator, Session Id";
 130                         break;
 131                 case 's':
 132                         typename = "Session Name";
 133                         break;
 134                 case 'i':
 135                         if (section == 'v')
 136                                 typename = "Session Information";
 137                         else if (section == 'm')
 138                                 typename = "Media Title";
 139                         else
 140                                 typename = "Misplaced";
 141                         break;
 142                 case 'u':
 143                         typename = "URI of Description";
 144                         break;
 145                 case 'e':
 146                         typename = "E-mail Address";
 147                         break;
 148                 case 'p':
 149                         typename = "Phone Number";
 150                         break;
 151                 case 'c':
 152                         typename = "Connection Information";
 153                         break;
 154                 case 'b':
 155                         typename = "Bandwidth Information";
 156                         break;
 157                 case 't':
 158                         section = 't';
 159                         typename = "Time Description, active time";
 160                         break;
 161                 case 'r':
 162                         typename = "Repeat Time";
 163                         break;
 164                 case 'm':
 165                         section = 'm';
 166                         typename = "Media Description, name and address";
 167                         break;
 168                 case 'k':
 169                         typename = "Encryption Key";
 170                         break;
 171                 case 'a':
 172                         if (section == 'v')
 173                                 typename = "Session Attribute";
 174                         else if (section == 'm')
 175                                 typename = "Media Attribute";
 176                         else
 177                                 typename = "Misplaced";
 178                         break;
 179                 case 'z':
 180                         typename = "Time Zone Adjustment";
 181                         break;
 182                 default:
 183                         typename = "Unknown";
 184                         break;
 185                 }
 186
 187                 proto_tree_add_text(sdp_tree, tvb, offset,
 188                     next_offset - offset,
 189                     "%s (%c): %s", typename, type,
 190                     format_text(value, valuelen));
 191                 offset = next_offset;
 192         }
 193
 194         datalen = tvb_length_remaining(tvb, offset);
 195         if (datalen > 0) {
 196                 proto_tree_add_text(sdp_tree, tvb, offset, datalen,
 197                     "Data (%d bytes)", datalen);
 198         }
 199 }
 200
 201 void
 202 proto_register_sdp(void)
 203 {
 204 /*        static hf_register_info hf[] = {
 205                 { &variable,
 206                 { "Name",           "sdp.abbreviation", TYPE, VALS_POINTER }},
 207         };*/
 208         static gint *ett[] = {
 209                 &ett_sdp,
 210         };
 211
 212         proto_sdp = proto_register_protocol("Session Description Protocol",
 213             "SDP", "sdp");
 214  /*       proto_register_field_array(proto_sdp, hf, array_length(hf));*/
 215         proto_register_subtree_array(ett, array_length(ett));
 216
 217         /*
 218          * Register the dissector by name, so other dissectors can
 219          * grab it by name rather than just referring to it directly
 220          * (you can't refer to it directly from a plugin dissector
 221          * on Windows without stuffing it into the Big Transfer Vector).
 222          */
 223         register_dissector("sdp", dissect_sdp, proto_sdp);
 224 }