epan/dissectors/packet-tali.c

   1 /* packet-tali.c
   2  *
   3  * Routines for Transport Adapter Layer Interface (TALI) version 1.0 dissection (RFC 3094)
   4  *
   5  * Copyright : 2004 Viorel Suman, <vsuman[AT]avmob.ro>
   6  *             In association with Avalanche Mobile BV, http://www.avmob.com
   7  *
   8  * Dissector of a TALI (Transport Adapter Layer Interface) version 1.0, as defined by the
   9  * Tekelec (www.tekelec.com) in RFC 3094, https://www.ietf.org/rfc/rfc3094
  10  *
  11  * Refer to the AUTHORS file or the AUTHORS section in the man page
  12  * for contacting the author(s) of this file.
  13  *
  14  * Wireshark - Network traffic analyzer
  15  * By Gerald Combs <gerald@wireshark.org>
  16  * Copyright 1998 Gerald Combs
  17  *
  18  * SPDX-License-Identifier: GPL-2.0-or-later
  19  */
  20 #include "config.h"
  21
  22 #include <epan/packet.h>
  23 #include <epan/prefs.h>
  24 #include "packet-tcp.h"
  25
  26 #define TALI_SYNC_LENGTH    4
  27 #define TALI_OPCODE_LENGTH  4
  28 #define TALI_MSU_LENGTH     2
  29 #define TALI_HEADER_LENGTH  TALI_SYNC_LENGTH + TALI_OPCODE_LENGTH + TALI_MSU_LENGTH
  30
  31 #define TALI_SYNC "TALI"
  32 #define TALI_TEST "test"
  33 #define TALI_ALLO "allo"
  34 #define TALI_PROH "proh"
  35 #define TALI_PROA "proa"
  36 #define TALI_MONI "moni"
  37 #define TALI_MONA "mona"
  38 #define TALI_SCCP "sccp"
  39 #define TALI_ISOT "isot"
  40 #define TALI_MTP3 "mtp3"
  41 #define TALI_SAAL "saal"
  42
  43 void proto_reg_handoff_tali(void);
  44 void proto_register_tali(void);
  45
  46 static int proto_tali;
  47
  48 static int hf_tali_length_indicator;
  49 static int hf_tali_opcode_indicator;
  50 static int hf_tali_sync_indicator;
  51
  52 /* Initialize the subtree pointers */
  53 static int ett_tali;
  54 static int ett_tali_sync;
  55 static int ett_tali_opcode;
  56 static int ett_tali_msu_length;
  57
  58 static dissector_table_t tali_dissector_table;
  59
  60 /* Desegment TALI messages */
  61 static bool tali_desegment = true;
  62
  63 /* Code to actually dissect the packets */
  64 static unsigned
  65 get_tali_pdu_len(packet_info *pinfo _U_, tvbuff_t *tvb, int offset, void *data _U_)
  66 {
  67   uint16_t length;
  68
  69   length = tvb_get_letohs(tvb, offset + TALI_SYNC_LENGTH + TALI_OPCODE_LENGTH);
  70   return length+TALI_HEADER_LENGTH;
  71 }
  72
  73 static int
  74 dissect_tali_pdu(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void* data _U_)
  75 {
  76   char *opcode; /* TALI opcode */
  77   uint16_t length; /* TALI length */
  78   tvbuff_t *payload_tvb = NULL;
  79
  80   /* Set up structures needed to add the protocol subtree and manage it */
  81   proto_item *tali_item = NULL;
  82   proto_tree *tali_tree = NULL;
  83
  84   opcode = (char *) tvb_get_string_enc(pinfo->pool, tvb, TALI_SYNC_LENGTH, TALI_OPCODE_LENGTH, ENC_ASCII|ENC_NA);
  85   length = tvb_get_letohs(tvb, TALI_SYNC_LENGTH + TALI_OPCODE_LENGTH);
  86
  87   /* Make entries in Protocol column on summary display */
  88   col_set_str(pinfo->cinfo, COL_PROTOCOL, "TALI");
  89
  90   col_clear(pinfo->cinfo, COL_INFO);
  91   col_append_fstr(pinfo->cinfo, COL_INFO, "[%s] packet, [%u] bytes in payload", opcode, length);
  92
  93   if (tree) {
  94     /* create display subtree for the protocol */
  95     tali_item = proto_tree_add_item(tree, proto_tali, tvb, 0, TALI_HEADER_LENGTH, ENC_NA);
  96     tali_tree = proto_item_add_subtree(tali_item, ett_tali);
  97     proto_tree_add_string(tali_tree, hf_tali_sync_indicator,   tvb, 0, TALI_SYNC_LENGTH, TALI_SYNC);
  98     proto_tree_add_string(tali_tree, hf_tali_opcode_indicator, tvb, TALI_SYNC_LENGTH, TALI_OPCODE_LENGTH, opcode);
  99     proto_tree_add_uint(tali_tree, hf_tali_length_indicator, tvb, TALI_SYNC_LENGTH + TALI_OPCODE_LENGTH, TALI_MSU_LENGTH, length);
 100   }
 101
 102   if (length > 0) {
 103     payload_tvb = tvb_new_subset_remaining(tvb, TALI_HEADER_LENGTH);
 104     if (payload_tvb != NULL && !dissector_try_string(tali_dissector_table, opcode, payload_tvb, pinfo, tree, NULL)) {
 105       call_data_dissector(payload_tvb, pinfo, tree);
 106     }
 107   }
 108
 109   return tvb_captured_length(tvb);
 110 }
 111
 112 static int
 113 dissect_tali(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void* data)
 114 {
 115   tcp_dissect_pdus(tvb, pinfo, tree, tali_desegment, TALI_HEADER_LENGTH,
 116                    get_tali_pdu_len, dissect_tali_pdu, data);
 117   return tvb_captured_length(tvb);
 118 }
 119
 120 /*
 121  * A 'heuristic dissector' that attemtps to establish whether we have
 122  * a TALI MSU here.
 123  * Only works when:
 124  *   the fixed header is there
 125  *   it is a 'well-known' operation
 126  */
 127 static bool
 128 dissect_tali_heur(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void *data)
 129 {
 130   char opcode[TALI_OPCODE_LENGTH]; /* TALI opcode */
 131
 132   /*
 133    * If we don't have at least TALI_HEADER_LENGTH bytes worth of captured
 134    * data (i.e., available to look at), we can't determine whether this
 135    * looks like a TALI packet or not.  We must use tvb_captured_length()
 136    * because the data must be present in the capture, not sliced off due
 137    * to the snapshot length specified for the capture.
 138    */
 139   if (tvb_captured_length(tvb) < TALI_HEADER_LENGTH)   /* Mandatory header */
 140     return false;
 141
 142   if (tvb_strneql(tvb, 0, TALI_SYNC, TALI_SYNC_LENGTH) != 0)
 143     return false;
 144
 145   tvb_memcpy(tvb, (uint8_t*)opcode, TALI_SYNC_LENGTH, TALI_OPCODE_LENGTH);
 146   if (strncmp(opcode, TALI_TEST, TALI_OPCODE_LENGTH) != 0 &&
 147       strncmp(opcode, TALI_ALLO, TALI_OPCODE_LENGTH) != 0 &&
 148       strncmp(opcode, TALI_PROH, TALI_OPCODE_LENGTH) != 0 &&
 149       strncmp(opcode, TALI_PROA, TALI_OPCODE_LENGTH) != 0 &&
 150       strncmp(opcode, TALI_MONI, TALI_OPCODE_LENGTH) != 0 &&
 151       strncmp(opcode, TALI_MONA, TALI_OPCODE_LENGTH) != 0 &&
 152       strncmp(opcode, TALI_SCCP, TALI_OPCODE_LENGTH) != 0 &&
 153       strncmp(opcode, TALI_ISOT, TALI_OPCODE_LENGTH) != 0 &&
 154       strncmp(opcode, TALI_MTP3, TALI_OPCODE_LENGTH) != 0 &&
 155       strncmp(opcode, TALI_SAAL, TALI_OPCODE_LENGTH) != 0)
 156     return false;
 157
 158   dissect_tali(tvb, pinfo, tree, data);
 159   return true;
 160 }
 161
 162 void
 163 proto_register_tali(void)
 164 {
 165   static hf_register_info hf[] = {
 166     { &hf_tali_sync_indicator,
 167       { "Sync", "tali.sync",
 168         FT_STRING, BASE_NONE, NULL, 0x00,
 169         "TALI SYNC", HFILL }
 170     },
 171     { &hf_tali_opcode_indicator,
 172       { "Opcode", "tali.opcode",
 173         FT_STRING, BASE_NONE, NULL, 0x00,
 174         "TALI Operation Code", HFILL }
 175     },
 176     { &hf_tali_length_indicator,
 177       { "Length", "tali.msu_length",
 178         FT_UINT16, BASE_DEC, NULL, 0x00,
 179         "TALI MSU Length", HFILL }
 180     },
 181   };
 182
 183   /* Setup protocol subtree array */
 184   static int *ett[] = {
 185     &ett_tali,
 186     &ett_tali_sync,
 187     &ett_tali_opcode,
 188     &ett_tali_msu_length
 189   };
 190   module_t *tali_module;
 191
 192   /* Register the protocol name and description */
 193   proto_tali = proto_register_protocol("Transport Adapter Layer Interface v1.0, RFC 3094", "TALI", "tali");
 194   proto_register_field_array(proto_tali, hf, array_length(hf));
 195   proto_register_subtree_array(ett, array_length(ett));
 196
 197   register_dissector("tali", dissect_tali, proto_tali);
 198
 199   tali_dissector_table = register_dissector_table("tali.opcode", "Tali OPCODE", proto_tali, FT_STRING, STRING_CASE_SENSITIVE);
 200
 201   tali_module = prefs_register_protocol(proto_tali, NULL);
 202   prefs_register_bool_preference(tali_module, "reassemble",
 203         "Reassemble TALI messages spanning multiple TCP segments",
 204         "Whether the TALI dissector should reassemble messages spanning multiple TCP segments."
 205         " To use this option, you must also enable \"Allow subdissectors to reassemble TCP streams\" in the TCP protocol settings.",
 206     &tali_desegment);
 207 }
 208
 209 void
 210 proto_reg_handoff_tali(void)
 211 {
 212   heur_dissector_add("tcp", dissect_tali_heur, "Tali over TCP", "tali_tcp", proto_tali, HEURISTIC_ENABLE);
 213 }
 214
 215 /*
 216  * Editor modelines  -  https://www.wireshark.org/tools/modelines.html
 217  *
 218  * Local Variables:
 219  * c-basic-offset: 2
 220  * tab-width: 8
 221  * indent-tabs-mode: nil
 222  * End:
 223  *
 224  * ex: set shiftwidth=2 tabstop=8 expandtab:
 225  * :indentSize=2:tabSize=8:noTabs=true:
 226  */