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 <wsutil/array.h>
  25 #include "packet-tcp.h"
  26
  27 #define TALI_SYNC_LENGTH    4
  28 #define TALI_OPCODE_LENGTH  4
  29 #define TALI_MSU_LENGTH     2
  30 #define TALI_HEADER_LENGTH  TALI_SYNC_LENGTH + TALI_OPCODE_LENGTH + TALI_MSU_LENGTH
  31
  32 #define TALI_SYNC "TALI"
  33 #define TALI_TEST "test"
  34 #define TALI_ALLO "allo"
  35 #define TALI_PROH "proh"
  36 #define TALI_PROA "proa"
  37 #define TALI_MONI "moni"
  38 #define TALI_MONA "mona"
  39 #define TALI_SCCP "sccp"
  40 #define TALI_ISOT "isot"
  41 #define TALI_MTP3 "mtp3"
  42 #define TALI_SAAL "saal"
  43
  44 void proto_reg_handoff_tali(void);
  45 void proto_register_tali(void);
  46
  47 static int proto_tali;
  48
  49 static int hf_tali_length_indicator;
  50 static int hf_tali_opcode_indicator;
  51 static int hf_tali_sync_indicator;
  52
  53 /* Initialize the subtree pointers */
  54 static int ett_tali;
  55 static int ett_tali_sync;
  56 static int ett_tali_opcode;
  57 static int ett_tali_msu_length;
  58
  59 static dissector_table_t tali_dissector_table;
  60
  61 /* Desegment TALI messages */
  62 static bool tali_desegment = true;
  63
  64 /* Code to actually dissect the packets */
  65 static unsigned
  66 get_tali_pdu_len(packet_info *pinfo _U_, tvbuff_t *tvb, int offset, void *data _U_)
  67 {
  68   uint16_t length;
  69
  70   length = tvb_get_letohs(tvb, offset + TALI_SYNC_LENGTH + TALI_OPCODE_LENGTH);
  71   return length+TALI_HEADER_LENGTH;
  72 }
  73
  74 static int
  75 dissect_tali_pdu(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void* data _U_)
  76 {
  77   char *opcode; /* TALI opcode */
  78   uint16_t length; /* TALI length */
  79   tvbuff_t *payload_tvb = NULL;
  80
  81   /* Set up structures needed to add the protocol subtree and manage it */
  82   proto_item *tali_item = NULL;
  83   proto_tree *tali_tree = NULL;
  84
  85   opcode = (char *) tvb_get_string_enc(pinfo->pool, tvb, TALI_SYNC_LENGTH, TALI_OPCODE_LENGTH, ENC_ASCII|ENC_NA);
  86   length = tvb_get_letohs(tvb, TALI_SYNC_LENGTH + TALI_OPCODE_LENGTH);
  87
  88   /* Make entries in Protocol column on summary display */
  89   col_set_str(pinfo->cinfo, COL_PROTOCOL, "TALI");
  90
  91   col_clear(pinfo->cinfo, COL_INFO);
  92   col_append_fstr(pinfo->cinfo, COL_INFO, "[%s] packet, [%u] bytes in payload", opcode, length);
  93
  94   if (tree) {
  95     /* create display subtree for the protocol */
  96     tali_item = proto_tree_add_item(tree, proto_tali, tvb, 0, TALI_HEADER_LENGTH, ENC_NA);
  97     tali_tree = proto_item_add_subtree(tali_item, ett_tali);
  98     proto_tree_add_string(tali_tree, hf_tali_sync_indicator,   tvb, 0, TALI_SYNC_LENGTH, TALI_SYNC);
  99     proto_tree_add_string(tali_tree, hf_tali_opcode_indicator, tvb, TALI_SYNC_LENGTH, TALI_OPCODE_LENGTH, opcode);
 100     proto_tree_add_uint(tali_tree, hf_tali_length_indicator, tvb, TALI_SYNC_LENGTH + TALI_OPCODE_LENGTH, TALI_MSU_LENGTH, length);
 101   }
 102
 103   if (length > 0) {
 104     payload_tvb = tvb_new_subset_remaining(tvb, TALI_HEADER_LENGTH);
 105     if (payload_tvb != NULL && !dissector_try_string_with_data(tali_dissector_table, opcode, payload_tvb, pinfo, tree, true, NULL)) {
 106       call_data_dissector(payload_tvb, pinfo, tree);
 107     }
 108   }
 109
 110   return tvb_captured_length(tvb);
 111 }
 112
 113 static int
 114 dissect_tali(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void* data)
 115 {
 116   tcp_dissect_pdus(tvb, pinfo, tree, tali_desegment, TALI_HEADER_LENGTH,
 117                    get_tali_pdu_len, dissect_tali_pdu, data);
 118   return tvb_captured_length(tvb);
 119 }
 120
 121 /*
 122  * A 'heuristic dissector' that attemtps to establish whether we have
 123  * a TALI MSU here.
 124  * Only works when:
 125  *   the fixed header is there
 126  *   it is a 'well-known' operation
 127  */
 128 static bool
 129 dissect_tali_heur(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void *data)
 130 {
 131   char opcode[TALI_OPCODE_LENGTH]; /* TALI opcode */
 132
 133   /*
 134    * If we don't have at least TALI_HEADER_LENGTH bytes worth of captured
 135    * data (i.e., available to look at), we can't determine whether this
 136    * looks like a TALI packet or not.  We must use tvb_captured_length()
 137    * because the data must be present in the capture, not sliced off due
 138    * to the snapshot length specified for the capture.
 139    */
 140   if (tvb_captured_length(tvb) < TALI_HEADER_LENGTH)   /* Mandatory header */
 141     return false;
 142
 143   if (tvb_strneql(tvb, 0, TALI_SYNC, TALI_SYNC_LENGTH) != 0)
 144     return false;
 145
 146   tvb_memcpy(tvb, (uint8_t*)opcode, TALI_SYNC_LENGTH, TALI_OPCODE_LENGTH);
 147   if (strncmp(opcode, TALI_TEST, TALI_OPCODE_LENGTH) != 0 &&
 148       strncmp(opcode, TALI_ALLO, TALI_OPCODE_LENGTH) != 0 &&
 149       strncmp(opcode, TALI_PROH, TALI_OPCODE_LENGTH) != 0 &&
 150       strncmp(opcode, TALI_PROA, TALI_OPCODE_LENGTH) != 0 &&
 151       strncmp(opcode, TALI_MONI, TALI_OPCODE_LENGTH) != 0 &&
 152       strncmp(opcode, TALI_MONA, TALI_OPCODE_LENGTH) != 0 &&
 153       strncmp(opcode, TALI_SCCP, TALI_OPCODE_LENGTH) != 0 &&
 154       strncmp(opcode, TALI_ISOT, TALI_OPCODE_LENGTH) != 0 &&
 155       strncmp(opcode, TALI_MTP3, TALI_OPCODE_LENGTH) != 0 &&
 156       strncmp(opcode, TALI_SAAL, TALI_OPCODE_LENGTH) != 0)
 157     return false;
 158
 159   dissect_tali(tvb, pinfo, tree, data);
 160   return true;
 161 }
 162
 163 void
 164 proto_register_tali(void)
 165 {
 166   static hf_register_info hf[] = {
 167     { &hf_tali_sync_indicator,
 168       { "Sync", "tali.sync",
 169         FT_STRING, BASE_NONE, NULL, 0x00,
 170         "TALI SYNC", HFILL }
 171     },
 172     { &hf_tali_opcode_indicator,
 173       { "Opcode", "tali.opcode",
 174         FT_STRING, BASE_NONE, NULL, 0x00,
 175         "TALI Operation Code", HFILL }
 176     },
 177     { &hf_tali_length_indicator,
 178       { "Length", "tali.msu_length",
 179         FT_UINT16, BASE_DEC, NULL, 0x00,
 180         "TALI MSU Length", HFILL }
 181     },
 182   };
 183
 184   /* Setup protocol subtree array */
 185   static int *ett[] = {
 186     &ett_tali,
 187     &ett_tali_sync,
 188     &ett_tali_opcode,
 189     &ett_tali_msu_length
 190   };
 191   module_t *tali_module;
 192
 193   /* Register the protocol name and description */
 194   proto_tali = proto_register_protocol("Transport Adapter Layer Interface v1.0, RFC 3094", "TALI", "tali");
 195   proto_register_field_array(proto_tali, hf, array_length(hf));
 196   proto_register_subtree_array(ett, array_length(ett));
 197
 198   register_dissector("tali", dissect_tali, proto_tali);
 199
 200   tali_dissector_table = register_dissector_table("tali.opcode", "Tali OPCODE", proto_tali, FT_STRING, STRING_CASE_SENSITIVE);
 201
 202   tali_module = prefs_register_protocol(proto_tali, NULL);
 203   prefs_register_bool_preference(tali_module, "reassemble",
 204         "Reassemble TALI messages spanning multiple TCP segments",
 205         "Whether the TALI dissector should reassemble messages spanning multiple TCP segments."
 206         " To use this option, you must also enable \"Allow subdissectors to reassemble TCP streams\" in the TCP protocol settings.",
 207     &tali_desegment);
 208 }
 209
 210 void
 211 proto_reg_handoff_tali(void)
 212 {
 213   heur_dissector_add("tcp", dissect_tali_heur, "Tali over TCP", "tali_tcp", proto_tali, HEURISTIC_ENABLE);
 214 }
 215
 216 /*
 217  * Editor modelines  -  https://www.wireshark.org/tools/modelines.html
 218  *
 219  * Local Variables:
 220  * c-basic-offset: 2
 221  * tab-width: 8
 222  * indent-tabs-mode: nil
 223  * End:
 224  *
 225  * ex: set shiftwidth=2 tabstop=8 expandtab:
 226  * :indentSize=2:tabSize=8:noTabs=true:
 227  */