epan/dissectors/packet-db-lsp.c

   1 /* packet-db-lsp.c
   2  * Routines for Dropbox LAN sync Protocol
   3  *
   4  * Copyright 2010, Stig Bjorlykke <stig@bjorlykke.org>
   5  *
   6  * Wireshark - Network traffic analyzer
   7  * By Gerald Combs <gerald@wireshark.org>
   8  * Copyright 1998 Gerald Combs
   9  *
  10  * SPDX-License-Identifier: GPL-2.0-or-later
  11  */
  12
  13 #include "config.h"
  14
  15 #include <epan/packet.h>
  16 #include <epan/asn1.h>
  17 #include <epan/prefs.h>
  18
  19 #include "packet-tcp.h"
  20 #include "packet-x509af.h"
  21
  22 #define PNAME  "Dropbox LAN sync Protocol"
  23 #define PSNAME "DB-LSP"
  24 #define PFNAME "db-lsp"
  25
  26 #define PNAME_DISC  "Dropbox LAN sync Discovery Protocol"
  27 #define PSNAME_DISC "DB-LSP-DISC"
  28 #define PFNAME_DISC "db-lsp-disc"
  29
  30 #define DB_LSP_PORT  17500
  31
  32 void proto_register_db_lsp(void);
  33 void proto_reg_handoff_db_lsp(void);
  34
  35 static int proto_db_lsp;
  36 static int proto_db_lsp_disc;
  37
  38 static int hf_type;
  39 static int hf_magic;
  40 static int hf_length;
  41 static int hf_opvalue;
  42 static int hf_data;
  43 static int hf_value;
  44 static int hf_text;
  45
  46 static int ett_db_lsp;
  47
  48 static heur_dissector_list_t heur_subdissector_list;
  49
  50 static dissector_handle_t db_lsp_tcp_handle;
  51 static dissector_handle_t db_lsp_udp_handle;
  52
  53 /* Use heuristic */
  54 static bool try_heuristic = true;
  55 /* desegmentation of tcp payload */
  56 static bool db_lsp_desegment = true;
  57
  58 #define TYPE_CONFIG   0x16
  59 #define TYPE_DATA     0x17
  60
  61 static const value_string type_vals[] = {
  62   { TYPE_CONFIG,    "Configuration" },
  63   { TYPE_DATA,      "Data" },
  64   { 0, NULL }
  65 };
  66
  67 #define OP_CERT       0x0B
  68
  69 static const value_string op_vals[] = {
  70   { OP_CERT,   "Certificate" },
  71   { 0, NULL }
  72 };
  73
  74 static int
  75 dissect_db_lsp_pdu (tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void* data _U_)
  76 {
  77   proto_tree *db_lsp_tree;
  78   proto_item *db_lsp_item;
  79   int         offset = 0;
  80   uint8_t     type, opvalue;
  81   uint16_t    magic, length;
  82
  83   col_set_str (pinfo->cinfo, COL_PROTOCOL, PSNAME);
  84   col_set_str (pinfo->cinfo, COL_INFO, PNAME);
  85
  86   db_lsp_item = proto_tree_add_item (tree, proto_db_lsp, tvb, offset, -1, ENC_NA);
  87   db_lsp_tree = proto_item_add_subtree (db_lsp_item, ett_db_lsp);
  88
  89   type = tvb_get_uint8 (tvb, offset);
  90   proto_tree_add_item (db_lsp_tree, hf_type, tvb, offset, 1, ENC_BIG_ENDIAN);
  91   offset += 1;
  92
  93   if (type == 0x80) {
  94     /* Two unknown bytes */
  95     offset += 2;
  96   }
  97
  98   magic = tvb_get_ntohs (tvb, offset);
  99   proto_tree_add_item (db_lsp_tree, hf_magic, tvb, offset, 2, ENC_BIG_ENDIAN);
 100   offset += 2;
 101
 102   length = tvb_get_ntohs (tvb, offset);
 103   proto_tree_add_item (db_lsp_tree, hf_length, tvb, offset, 2, ENC_BIG_ENDIAN);
 104   offset += 2;
 105
 106   if (magic != 0x0301 || length > tvb_reported_length_remaining (tvb, offset)) {
 107     /* Probably an unknown packet */
 108     /* expert_add_info_format (pinfo, db_lsp_item, PI_UNDECODED, PI_WARN, "Unknown packet"); */
 109     return 0;
 110   }
 111
 112   if (type == TYPE_CONFIG) {
 113     opvalue = tvb_get_uint8 (tvb, offset);
 114     proto_tree_add_item (db_lsp_tree, hf_opvalue, tvb, offset, 1, ENC_BIG_ENDIAN);
 115
 116     if (opvalue == OP_CERT) {
 117       /* X509 Certificate */
 118       tvbuff_t *cert_tvb = tvb_new_subset_length (tvb, offset+10, length-10);
 119       dissect_x509af_Certificate_PDU (cert_tvb, pinfo, db_lsp_tree, NULL);
 120     } else {
 121       proto_tree_add_item (db_lsp_tree, hf_value, tvb, offset, length, ENC_NA);
 122     }
 123   } else if (type == TYPE_DATA) {
 124     proto_tree_add_item (db_lsp_tree, hf_data, tvb, offset, length, ENC_NA);
 125   } else {
 126     proto_tree_add_item (db_lsp_tree, hf_value, tvb, offset, length, ENC_NA);
 127   }
 128   /*offset += length;*/
 129
 130   proto_item_append_text (db_lsp_item, ", Type: %d, Length: %d", type, length);
 131   proto_item_set_len (db_lsp_item, length + 5);
 132   return tvb_reported_length(tvb);
 133 }
 134
 135 static unsigned
 136 get_db_lsp_pdu_len (packet_info *pinfo _U_, tvbuff_t *tvb,
 137                     int offset, void *data _U_)
 138 {
 139   if (tvb_get_ntohs (tvb, offset + 1) != 0x0301) {
 140     /* Unknown data, eat remaining data for this frame */
 141     return tvb_reported_length_remaining (tvb, offset);
 142   }
 143
 144   return tvb_get_ntohs (tvb, offset + 3) + 5;
 145 }
 146
 147 static int
 148 dissect_db_lsp_tcp (tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void* data)
 149 {
 150   tcp_dissect_pdus (tvb, pinfo, tree, db_lsp_desegment, 5,
 151                     get_db_lsp_pdu_len, dissect_db_lsp_pdu, data);
 152   return tvb_reported_length(tvb);
 153 }
 154
 155 static int
 156 dissect_db_lsp_disc (tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void* data _U_)
 157 {
 158   proto_tree *db_lsp_tree;
 159   proto_item *db_lsp_item;
 160   int         offset = 0;
 161   heur_dtbl_entry_t *hdtbl_entry;
 162   proto_tree *data_subtree;
 163
 164   col_set_str (pinfo->cinfo, COL_PROTOCOL, PSNAME_DISC);
 165   col_set_str (pinfo->cinfo, COL_INFO, PNAME_DISC);
 166
 167   db_lsp_item = proto_tree_add_item (tree, proto_db_lsp_disc, tvb, offset, -1, ENC_NA);
 168   db_lsp_tree = proto_item_add_subtree (db_lsp_item, ett_db_lsp);
 169
 170   /* try the heuristic dissectors */
 171   if (try_heuristic) {
 172     data_subtree = proto_item_add_subtree(db_lsp_item, ett_db_lsp);
 173     if (dissector_try_heuristic(heur_subdissector_list, tvb, pinfo, data_subtree, &hdtbl_entry, NULL)) {
 174       return tvb_captured_length(tvb);
 175     }
 176   }
 177
 178   /* heuristic failed. Print remaining bytes as text */
 179   proto_tree_add_item (db_lsp_tree, hf_text, tvb, offset, -1, ENC_ASCII);
 180   return tvb_captured_length(tvb);
 181 }
 182
 183 void
 184 proto_register_db_lsp (void)
 185 {
 186   static hf_register_info hf[] = {
 187     { &hf_type,
 188       { "Type", "db-lsp.type",
 189         FT_UINT8, BASE_DEC_HEX, VALS(type_vals), 0x0,
 190         NULL, HFILL } },
 191
 192     { &hf_magic,
 193       { "Magic", "db-lsp.magic",
 194         FT_UINT16, BASE_DEC_HEX, NULL, 0x0,
 195         "Magic number", HFILL } },
 196
 197     { &hf_length,
 198       { "Length", "db-lsp.length",
 199         FT_UINT16, BASE_DEC_HEX, NULL, 0x0,
 200         "Length in bytes", HFILL } },
 201
 202     { &hf_opvalue,
 203       { "OP Value", "db-lsp.op",
 204         FT_UINT8, BASE_DEC_HEX, VALS(op_vals), 0x0,
 205         NULL, HFILL } },
 206
 207     { &hf_value,
 208       { "Value", "db-lsp.value",
 209         FT_BYTES, BASE_NONE, NULL, 0x0,
 210         NULL, HFILL } },
 211
 212     { &hf_data,
 213       { "Data", "db-lsp.data",
 214         FT_BYTES, BASE_NONE, NULL, 0x0,
 215         NULL, HFILL } },
 216
 217     { &hf_text,
 218       { "Text", "db-lsp.text",
 219         FT_STRING, BASE_NONE, NULL, 0x0,
 220         NULL, HFILL } },
 221   };
 222
 223   static int *ett[] = {
 224     &ett_db_lsp,
 225   };
 226
 227   module_t *db_lsp_module;
 228
 229   proto_db_lsp = proto_register_protocol (PNAME, PSNAME, PFNAME);
 230   proto_db_lsp_disc = proto_register_protocol (PNAME_DISC, PSNAME_DISC, PFNAME_DISC);
 231   db_lsp_tcp_handle = register_dissector ("db-lsp.tcp", dissect_db_lsp_tcp, proto_db_lsp);
 232   db_lsp_udp_handle = register_dissector ("db-lsp.udp", dissect_db_lsp_disc, proto_db_lsp_disc);
 233
 234   heur_subdissector_list = register_heur_dissector_list_with_description("db-lsp", PSNAME_DISC " payload", proto_db_lsp);
 235
 236   proto_register_field_array (proto_db_lsp, hf, array_length (hf));
 237   proto_register_subtree_array (ett, array_length (ett));
 238
 239   /* Register our configuration options */
 240   db_lsp_module = prefs_register_protocol (proto_db_lsp, NULL);
 241
 242   prefs_register_bool_preference (db_lsp_module, "desegment_pdus",
 243                                   "Reassemble PDUs spanning multiple TCP segments",
 244                                   "Whether the LAN sync dissector should reassemble PDUs"
 245                                   " spanning multiple TCP segments."
 246                                   " To use this option, you must also enable \"Allow subdissectors"
 247                                   " to reassemble TCP streams\" in the TCP protocol settings.",
 248                                   &db_lsp_desegment);
 249
 250   prefs_register_bool_preference(db_lsp_module, "try_heuristic",
 251                                   "Try heuristic sub-dissectors",
 252                                   "Try to decode the payload using an heuristic sub-dissector",
 253                                   &try_heuristic);
 254 }
 255
 256 void
 257 proto_reg_handoff_db_lsp (void)
 258 {
 259   dissector_add_uint_with_preference("tcp.port", DB_LSP_PORT, db_lsp_tcp_handle);
 260   dissector_add_uint_with_preference("udp.port", DB_LSP_PORT, db_lsp_udp_handle);
 261 }
 262
 263 /*
 264  * Editor modelines
 265  *
 266  * Local Variables:
 267  * c-basic-offset: 2
 268  * tab-width: 8
 269  * indent-tabs-mode: nil
 270  * End:
 271  *
 272  * ex: set shiftwidth=2 tabstop=8 expandtab:
 273  * :indentSize=2:tabSize=8:noTabs=true:
 274  */