epan/dissectors/packet-bzr.c

   1 /* packet-bzr.c
   2  * Routines for Bazaar packet dissection
   3  * Copyright 2011, Jelmer Vernooij <jelmer@samba.org>
   4  *
   5  * http://doc.bazaar.canonical.com/developers/network-protocol.html
   6  *
   7  * $Id$
   8  *
   9  * Wireshark - Network traffic analyzer
  10  * By Gerald Combs <gerald@wireshark.org>
  11  * Copyright 1998 Gerald Combs
  12  *
  13  * Copied from packet-pop.c
  14  *
  15  * This program is free software; you can redistribute it and/or
  16  * modify it under the terms of the GNU General Public License
  17  * as published by the Free Software Foundation; either version 2
  18  * of the License, or (at your option) any later version.
  19  *
  20  * This program is distributed in the hope that it will be useful,
  21  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  22  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  23  * GNU General Public License for more details.
  24  *
  25  * You should have received a copy of the GNU General Public License
  26  * along with this program; if not, write to the Free Software
  27  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  28  */
  29
  30 #include "config.h"
  31
  32 #include <glib.h>
  33 #include <epan/packet.h>
  34 #include <epan/prefs.h>
  35 #include "packet-tcp.h"
  36
  37 static int proto_bzr = -1;
  38
  39 static gint ett_bzr = -1;
  40 static gint ett_prefixed_bencode = -1;
  41 static gint ett_prefixed_bytes = -1;
  42
  43 static gint hf_bzr_prefixed_bencode = -1;
  44 static gint hf_bzr_prefixed_bencode_len = -1;
  45 static gint hf_bzr_prefixed_bencode_data = -1;
  46 static gint hf_bzr_bytes = -1;
  47 static gint hf_bzr_bytes_data = -1;
  48 static gint hf_bzr_bytes_length = -1;
  49 static gint hf_bzr_result = -1;
  50 static gint hf_bzr_packet_protocol_version = -1;
  51 static gint hf_bzr_packet_kind = -1;
  52
  53 #define REQUEST_VERSION_TWO   "bzr request 2\n"
  54 #define RESPONSE_VERSION_TWO  "bzr response 2\n"
  55 #define MESSAGE_VERSION_THREE "bzr message 3 (bzr 1.6)\n"
  56
  57 #define TCP_PORT_BZR   4155
  58
  59 static const value_string message_part_kind[] = {
  60     {'s', "Structure"},
  61     {'b', "Bytes"},
  62     {'o', "Single byte"},
  63     {'e', "End"},
  64     {0, NULL}
  65 };
  66
  67 static const value_string message_results[] = {
  68     {'S', "Success"},
  69     {'E', "Error"},
  70     {0, NULL}
  71 };
  72
  73 /* desegmentation of Bazaar over TCP */
  74 static gboolean bzr_desegment = TRUE;
  75
  76 static guint get_bzr_prefixed_len(tvbuff_t *tvb, int offset)
  77 {
  78     guint header_len;
  79     header_len = tvb_get_ntohl(tvb, offset);
  80     return 4 + header_len;
  81 }
  82
  83 static guint
  84 get_bzr_pdu_len(packet_info *pinfo _U_, tvbuff_t *tvb, int offset)
  85 {
  86     int    next_offset;
  87     gint   len = 0;
  88     gint   protocol_version_len;
  89     guint8 cmd = 0;
  90
  91     /* Protocol version */
  92     protocol_version_len = tvb_find_line_end(tvb, offset, -1, &next_offset,
  93                                              TRUE);
  94     if (protocol_version_len == -1) /* End of the packet not seen yet */
  95         return -1;
  96
  97     len += protocol_version_len + 1;
  98
  99     /* Headers */
 100     len += get_bzr_prefixed_len(tvb, next_offset);
 101
 102     while (tvb_reported_length_remaining(tvb, offset + len) > 0) {
 103         cmd = tvb_get_guint8(tvb, offset + len);
 104         len += 1;
 105
 106         switch (cmd) {
 107         case 's':
 108         case 'b':
 109             len += get_bzr_prefixed_len(tvb, offset + len);
 110             break;
 111         case 'o':
 112             len += 1;
 113             break;
 114         case 'e':
 115             return len;
 116         }
 117     }
 118
 119     return -1;
 120 }
 121
 122 static gint
 123 dissect_prefixed_bencode(tvbuff_t *tvb, gint offset, packet_info *pinfo _U_,
 124                          proto_tree *tree)
 125 {
 126     guint32     plen;
 127     proto_tree *prefixed_bencode_tree;
 128     proto_item *ti;
 129
 130     plen = tvb_get_ntohl(tvb, offset);
 131
 132     ti = proto_tree_add_item(tree, hf_bzr_prefixed_bencode, tvb, offset, 4 +
 133                              plen, ENC_NA);
 134     prefixed_bencode_tree = proto_item_add_subtree(ti, ett_prefixed_bencode);
 135
 136     if (prefixed_bencode_tree)
 137     {
 138         proto_tree_add_item(prefixed_bencode_tree, hf_bzr_prefixed_bencode_len,
 139                             tvb, offset, 4, ENC_BIG_ENDIAN);
 140
 141         proto_tree_add_item(prefixed_bencode_tree, hf_bzr_prefixed_bencode_data,
 142                             tvb, offset+4, plen, ENC_NA);
 143     }
 144
 145     return 4 + plen;
 146 }
 147
 148 static gint
 149 dissect_prefixed_bytes(tvbuff_t *tvb, gint offset, packet_info *pinfo _U_,
 150                        proto_tree *tree)
 151 {
 152     guint32     plen;
 153     proto_tree *prefixed_bytes_tree;
 154     proto_item *ti;
 155
 156     plen = tvb_get_ntohl(tvb, offset);
 157
 158     ti = proto_tree_add_item(tree, hf_bzr_bytes, tvb, offset, 4 +
 159                              plen, ENC_NA);
 160     prefixed_bytes_tree = proto_item_add_subtree(ti, ett_prefixed_bytes);
 161
 162     if (prefixed_bytes_tree)
 163     {
 164         proto_tree_add_item(prefixed_bytes_tree, hf_bzr_bytes_length,
 165                             tvb, offset, 4, ENC_BIG_ENDIAN);
 166
 167         proto_tree_add_item(prefixed_bytes_tree, hf_bzr_bytes_data,
 168                             tvb, offset+4, plen, ENC_NA);
 169     }
 170
 171     return 4 + plen;
 172 }
 173
 174 static gint
 175 dissect_body(tvbuff_t *tvb, gint offset, packet_info *pinfo, proto_tree *tree)
 176 {
 177     guint8 cmd = 0;
 178
 179     while (tvb_reported_length_remaining(tvb, offset) > 0) {
 180         cmd = tvb_get_guint8(tvb, offset);
 181         proto_tree_add_item(tree, hf_bzr_packet_kind, tvb, offset, 1, ENC_NA);
 182         offset += 1;
 183
 184         switch (cmd) {
 185         case 's':
 186             offset += dissect_prefixed_bencode(tvb, offset, pinfo, tree);
 187             break;
 188         case 'b':
 189             offset += dissect_prefixed_bytes(tvb, offset, pinfo, tree);
 190             break;
 191         case 'o':
 192             proto_tree_add_item(tree, hf_bzr_result, tvb, offset, 1,
 193                                 ENC_NA);
 194             offset += 1;
 195             break;
 196         case 'e':
 197             break;
 198         }
 199     }
 200
 201     return offset;
 202 }
 203
 204 static void
 205 dissect_bzr_pdu(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
 206 {
 207     proto_tree *bzr_tree;
 208     proto_item *ti;
 209     int         offset = 0;
 210     gint        protocol_version_len;
 211
 212     ti = proto_tree_add_item(tree, proto_bzr, tvb, offset, -1, ENC_NA);
 213     bzr_tree = proto_item_add_subtree(ti, ett_bzr);
 214
 215     protocol_version_len = tvb_find_line_end(tvb, offset, -1, &offset, TRUE);
 216     if (protocol_version_len == -1) /* Invalid packet */
 217         return;
 218
 219     if (bzr_tree)
 220     {
 221         proto_tree_add_item(bzr_tree, hf_bzr_packet_protocol_version, tvb, 0,
 222                             protocol_version_len+1, ENC_ASCII|ENC_NA);
 223     }
 224
 225     offset += dissect_prefixed_bencode(tvb, offset, pinfo, bzr_tree);
 226     /*offset +=*/ dissect_body(tvb, offset, pinfo, bzr_tree);
 227 }
 228
 229 static void
 230 dissect_bzr(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
 231 {
 232     gint      offset = 0, pdu_len;
 233     tvbuff_t *next_tvb;
 234
 235     col_set_str(pinfo->cinfo, COL_PROTOCOL, "BZR");
 236
 237     col_set_str(pinfo->cinfo, COL_INFO, "Bazaar Smart Protocol");
 238
 239     while (tvb_reported_length_remaining(tvb, offset) > 0) {
 240         pdu_len = get_bzr_pdu_len(pinfo, tvb, offset);
 241         if (pdu_len == -1) {
 242             if (pinfo->can_desegment && bzr_desegment) {
 243                 pinfo->desegment_offset = offset;
 244                 pinfo->desegment_len = DESEGMENT_ONE_MORE_SEGMENT;
 245                 return;
 246             } else {
 247                 pdu_len = tvb_reported_length_remaining(tvb, offset);
 248             }
 249         }
 250         next_tvb = tvb_new_subset(tvb, offset, pdu_len, pdu_len);
 251         dissect_bzr_pdu(next_tvb, pinfo, tree);
 252         offset += pdu_len;
 253     }
 254 }
 255
 256 void
 257 proto_register_bzr(void)
 258 {
 259     static hf_register_info hf[] = {
 260         { &hf_bzr_packet_kind,
 261           { "Packet kind", "bzr.kind", FT_UINT8, BASE_DEC,
 262             VALS(message_part_kind), 0x0, NULL, HFILL },
 263         },
 264         { &hf_bzr_packet_protocol_version,
 265           { "Protocol version", "bzr.protocol_version", FT_STRING, BASE_NONE,
 266             NULL, 0x0, NULL, HFILL },
 267         },
 268         { &hf_bzr_prefixed_bencode,
 269           { "Bencode packet", "bzr.bencode", FT_BYTES, BASE_NONE, NULL, 0x0,
 270             "Serialized structure of integers, dictionaries, strings and "
 271             "lists.", HFILL },
 272         },
 273         { &hf_bzr_prefixed_bencode_len,
 274           { "Bencode packet length", "bzr.bencode.length", FT_UINT32,
 275             BASE_HEX, NULL, 0x0, NULL, HFILL },
 276         },
 277         { &hf_bzr_prefixed_bencode_data,
 278           { "Bencode packet data", "bzr.bencode.data", FT_BYTES, BASE_NONE,
 279             NULL, 0x0, NULL, HFILL },
 280         },
 281         { &hf_bzr_bytes,
 282           { "Prefixed bytes", "bzr.bytes", FT_BYTES, BASE_NONE, NULL, 0x0,
 283             "Bytes field with prefixed 32-bit length", HFILL },
 284         },
 285         { &hf_bzr_bytes_data,
 286           { "Prefixed bytes data", "bzr.bytes.data", FT_BYTES, BASE_NONE,
 287             NULL, 0x0, NULL, HFILL },
 288         },
 289         { &hf_bzr_bytes_length,
 290           { "Prefixed bytes length", "bzr.bytes.length", FT_UINT32, BASE_HEX,
 291             NULL, 0x0, NULL, HFILL },
 292         },
 293         { &hf_bzr_result,
 294           { "Result", "bzr.result", FT_UINT8, BASE_HEX,
 295             VALS(message_results), 0x0,
 296             "Command result (success or failure with error message)", HFILL
 297           },
 298         },
 299     };
 300
 301     static gint *ett[] = {
 302         &ett_bzr,
 303         &ett_prefixed_bencode,
 304         &ett_prefixed_bytes,
 305     };
 306
 307     module_t *bzr_module;
 308     proto_bzr = proto_register_protocol("Bazaar Smart Protocol", "Bazaar", "bzr");
 309     register_dissector("bzr", dissect_bzr, proto_bzr);
 310     proto_register_field_array(proto_bzr, hf, array_length(hf));
 311     proto_register_subtree_array(ett, array_length(ett));
 312
 313     bzr_module = prefs_register_protocol(proto_bzr, NULL);
 314
 315     prefs_register_bool_preference(bzr_module, "desegment",
 316                                    "Reassemble Bazaar messages spanning multiple TCP segments",
 317                                    "Whether the Bazaar dissector should reassemble messages spanning multiple TCP segments."
 318                                    " To use this option, you must also enable \"Allow subdissectors to reassemble TCP streams\""
 319                                    " in the TCP protocol settings.",
 320                                    &bzr_desegment);
 321 }
 322
 323 void
 324 proto_reg_handoff_bzr(void)
 325 {
 326     dissector_handle_t bzr_handle;
 327
 328     bzr_handle = find_dissector("bzr");
 329     dissector_add_uint("tcp.port", TCP_PORT_BZR, bzr_handle);
 330 }