epan/dissectors/packet-interlink.c

   1 /* packet-interlink.c
   2  * Routines for Interlink protocol packet disassembly
   3  * By Uwe Girlich <uwe.girlich@philosys.de>
   4  * Copyright 2010 Uwe Girlich
   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/tfs.h>
  17 #include <wsutil/array.h>
  18
  19 void proto_register_interlink(void);
  20 void proto_reg_handoff_interlink(void);
  21
  22 /*
  23  * No public information available.
  24  */
  25
  26 static int proto_interlink;
  27
  28 static int hf_interlink_id;
  29 static int hf_interlink_version;
  30 static int hf_interlink_cmd;
  31 static int hf_interlink_seq;
  32 static int hf_interlink_flags;
  33 static int hf_interlink_flags_req_ack;
  34 static int hf_interlink_flags_inc_ack_port;
  35 static int hf_interlink_block_type;
  36 static int hf_interlink_block_version;
  37 static int hf_interlink_block_length;
  38
  39 static int ett_interlink;
  40 static int ett_interlink_header;
  41 static int ett_interlink_flags;
  42 static int ett_interlink_block;
  43
  44 static dissector_handle_t data_handle;
  45 static dissector_table_t subdissector_table;
  46 static dissector_handle_t interlink_handle;
  47
  48
  49 static const value_string names_cmd[] = {
  50         { 1, "Data" },
  51         { 2, "Ack" },
  52         { 0, NULL }
  53 };
  54
  55
  56 static int
  57 dissect_interlink(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void* data _U_)
  58 {
  59         int             offset = 0;
  60         proto_tree      *il_tree;
  61         proto_item      *il_item;
  62         proto_tree      *ilh_tree = NULL;
  63         proto_tree      *ilb_tree = NULL;
  64         uint8_t         ilb_type;
  65         uint8_t         ilb_version;
  66         uint16_t                type_version = 0;
  67         dissector_handle_t      handle;
  68         tvbuff_t        *next_tvb;
  69
  70         col_set_str(pinfo->cinfo, COL_PROTOCOL, "INTERLINK");
  71         col_clear(pinfo->cinfo, COL_INFO);
  72
  73         il_item = proto_tree_add_item(tree, proto_interlink,
  74                                                         tvb, 0, 16, ENC_NA);
  75         il_tree = proto_item_add_subtree(il_item, ett_interlink);
  76
  77         ilh_tree = proto_tree_add_subtree(il_tree, tvb, 0, 12, ett_interlink_header, NULL, "Interlink Header");
  78
  79         if (ilh_tree) {
  80                 proto_tree_add_item(ilh_tree, hf_interlink_id, tvb, offset, 4, ENC_ASCII);
  81                 offset += 4;
  82                 proto_tree_add_item(ilh_tree, hf_interlink_version, tvb, offset, 2, ENC_LITTLE_ENDIAN);
  83                 offset += 2;
  84                 proto_tree_add_item(ilh_tree, hf_interlink_cmd, tvb, offset, 2, ENC_LITTLE_ENDIAN);
  85                 offset += 2;
  86                 proto_tree_add_item(ilh_tree, hf_interlink_seq, tvb, offset, 2, ENC_LITTLE_ENDIAN);
  87                 offset += 2;
  88         } else {
  89                 offset += 10;
  90         }
  91
  92         if (ilh_tree) {
  93                 static int * const flags[] = {
  94                         &hf_interlink_flags_req_ack,
  95                         &hf_interlink_flags_inc_ack_port,
  96                         NULL
  97                 };
  98
  99                 proto_tree_add_bitmask(ilh_tree, tvb, offset, hf_interlink_flags, ett_interlink_flags, flags, ENC_LITTLE_ENDIAN);
 100
 101         }
 102         offset += 2;
 103
 104         ilb_tree = proto_tree_add_subtree(il_tree, tvb, offset, 4, ett_interlink_block, NULL, "Block Header");
 105
 106         ilb_type = tvb_get_uint8(tvb, offset);
 107         ilb_version = tvb_get_uint8(tvb, offset + 1);
 108         type_version = ilb_type << 8 | ilb_version;
 109         col_append_fstr(pinfo->cinfo, COL_INFO, "Type: %d, Version: %d",
 110                 ilb_type, ilb_version);
 111
 112         if (ilb_tree) {
 113                 proto_tree_add_item(ilb_tree, hf_interlink_block_type, tvb, offset, 1, ENC_BIG_ENDIAN);
 114                 offset += 1;
 115                 proto_tree_add_item(ilb_tree, hf_interlink_block_version, tvb, offset, 1, ENC_BIG_ENDIAN);
 116                 offset += 1;
 117                 proto_tree_add_item(ilb_tree, hf_interlink_block_length, tvb, offset, 2, ENC_LITTLE_ENDIAN);
 118                 offset += 2;
 119         } else {
 120                 offset += 4;
 121         }
 122
 123         /* Generate a new tvb for the rest. */
 124         next_tvb = tvb_new_subset_remaining(tvb, offset);
 125
 126         /* Probably a sub-dissector exists for this type/version combination. */
 127         handle = dissector_get_uint_handle(subdissector_table, type_version);
 128
 129         /* Without a proper sub-dissector, we use "data". */
 130         if (handle == NULL) handle = data_handle;
 131
 132         /* Call the sub-dissector. */
 133         call_dissector(handle, next_tvb, pinfo, tree);
 134
 135         return tvb_captured_length(tvb);
 136 }
 137
 138
 139 static bool
 140 dissect_interlink_heur(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void *data)
 141 {
 142         if (!tvb_bytes_exist(tvb, 0, 4)) {
 143                 return false;
 144         }
 145         if (
 146                 tvb_get_uint8(tvb,0) != 'I' ||
 147                 tvb_get_uint8(tvb,1) != 'L' ||
 148                 tvb_get_uint8(tvb,2) != 'N' ||
 149                 tvb_get_uint8(tvb,3) != 'K'
 150         )
 151                 return false;
 152
 153         dissect_interlink(tvb, pinfo, tree, data);
 154         return true;
 155 }
 156
 157
 158 void
 159 proto_register_interlink(void)
 160 {
 161         static hf_register_info hf[] = {
 162                 { &hf_interlink_id, {
 163                         "Magic ID", "interlink.id", FT_STRING,
 164                         BASE_NONE, NULL, 0, NULL, HFILL }},
 165                 { &hf_interlink_version, {
 166                         "Version", "interlink.version", FT_UINT16,
 167                         BASE_DEC, NULL, 0, NULL, HFILL }},
 168                 { &hf_interlink_cmd, {
 169                         "Command", "interlink.cmd", FT_UINT16,
 170                         BASE_DEC, VALS(names_cmd), 0, NULL, HFILL }},
 171                 { &hf_interlink_seq, {
 172                         "Sequence", "interlink.seq", FT_UINT16,
 173                         BASE_DEC, NULL, 0, NULL, HFILL }},
 174                 { &hf_interlink_flags, {
 175                         "Flags", "interlink.flags", FT_UINT16,
 176                         BASE_HEX, NULL, 0, NULL, HFILL }},
 177                 { &hf_interlink_flags_req_ack, {
 178                         "REQ_ACK", "interlink.flags.req_ack", FT_BOOLEAN,
 179                         16, TFS(&tfs_set_notset), 0x0001, NULL, HFILL }},
 180                 { &hf_interlink_flags_inc_ack_port, {
 181                         "INC_ACK_PORT", "interlink.flags.inc_ack_port", FT_BOOLEAN,
 182                         16, TFS(&tfs_set_notset), 0x0002, NULL, HFILL }},
 183                 { &hf_interlink_block_type, {
 184                         "Type", "interlink.type", FT_UINT8,
 185                         BASE_DEC, NULL, 0, NULL, HFILL }},
 186                 { &hf_interlink_block_version, {
 187                         "Version", "interlink.block_version", FT_UINT8,
 188                         BASE_DEC, NULL, 0, NULL, HFILL }},
 189                 { &hf_interlink_block_length, {
 190                         "Length", "interlink.length", FT_UINT16,
 191                         BASE_DEC, NULL, 0, NULL, HFILL }},
 192         };
 193
 194         static int *ett[] = {
 195                 &ett_interlink,
 196                 &ett_interlink_header,
 197                 &ett_interlink_flags,
 198                 &ett_interlink_block,
 199         };
 200
 201         proto_interlink = proto_register_protocol("Interlink Protocol",
 202                                                         "Interlink",
 203                                                         "interlink");
 204         proto_register_field_array(proto_interlink, hf, array_length(hf));
 205         proto_register_subtree_array(ett, array_length(ett));
 206         interlink_handle = register_dissector("interlink", dissect_interlink, proto_interlink);
 207
 208         /* Probably someone will write sub-dissectors. You can never know. */
 209         subdissector_table = register_dissector_table("interlink.type_version",
 210                 "Interlink type_version", proto_interlink, FT_UINT16, BASE_HEX);
 211 }
 212
 213
 214 void
 215 proto_reg_handoff_interlink(void)
 216 {
 217         /* Allow "Decode As" with any UDP packet. */
 218         dissector_add_for_decode_as_with_preference("udp.port", interlink_handle);
 219
 220         /* Add our heuristic packet finder. */
 221         heur_dissector_add("udp", dissect_interlink_heur, "Interlink over UDP", "interlink_udp", proto_interlink, HEURISTIC_ENABLE);
 222
 223         data_handle = find_dissector("data");
 224 }
 225
 226 /*
 227  * Editor modelines  -  https://www.wireshark.org/tools/modelines.html
 228  *
 229  * Local variables:
 230  * c-basic-offset: 8
 231  * tab-width: 8
 232  * indent-tabs-mode: t
 233  * End:
 234  *
 235  * vi: set shiftwidth=8 tabstop=8 noexpandtab:
 236  * :indentSize=8:tabSize=8:noTabs=false:
 237  */