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
  17 void proto_register_interlink(void);
  18 void proto_reg_handoff_interlink(void);
  19
  20 /*
  21  * No public information available.
  22  */
  23
  24 static int proto_interlink = -1;
  25
  26 static int hf_interlink_id = -1;
  27 static int hf_interlink_version = -1;
  28 static int hf_interlink_cmd = -1;
  29 static int hf_interlink_seq = -1;
  30 static int hf_interlink_flags = -1;
  31 static int hf_interlink_flags_req_ack = -1;
  32 static int hf_interlink_flags_inc_ack_port = -1;
  33 static int hf_interlink_block_type = -1;
  34 static int hf_interlink_block_version = -1;
  35 static int hf_interlink_block_length = -1;
  36
  37 static gint ett_interlink = -1;
  38 static gint ett_interlink_header = -1;
  39 static gint ett_interlink_flags = -1;
  40 static gint ett_interlink_block = -1;
  41
  42 static dissector_handle_t data_handle;
  43 static dissector_table_t subdissector_table;
  44 static dissector_handle_t interlink_handle;
  45
  46 static const true_false_string flags_set_notset = {
  47         "Set", "Not set"
  48 };
  49
  50 static const value_string names_cmd[] = {
  51         { 1, "Data" },
  52         { 2, "Ack" },
  53         { 0, NULL }
  54 };
  55
  56
  57 static int
  58 dissect_interlink(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void* data _U_)
  59 {
  60         int             offset = 0;
  61         proto_tree      *il_tree;
  62         proto_item      *il_item;
  63         proto_tree      *ilh_tree = NULL;
  64         proto_tree      *ilb_tree = NULL;
  65         guint8          ilb_type;
  66         guint8          ilb_version;
  67         guint16         type_version = 0;
  68         dissector_handle_t      handle;
  69         tvbuff_t        *next_tvb;
  70
  71         col_set_str(pinfo->cinfo, COL_PROTOCOL, "INTERLINK");
  72         col_clear(pinfo->cinfo, COL_INFO);
  73
  74         il_item = proto_tree_add_item(tree, proto_interlink,
  75                                                         tvb, 0, 16, ENC_NA);
  76         il_tree = proto_item_add_subtree(il_item, ett_interlink);
  77
  78         ilh_tree = proto_tree_add_subtree(il_tree, tvb, 0, 12, ett_interlink_header, NULL, "Interlink Header");
  79
  80         if (ilh_tree) {
  81                 proto_tree_add_item(ilh_tree, hf_interlink_id, tvb, offset, 4, ENC_ASCII|ENC_NA);
  82                 offset += 4;
  83                 proto_tree_add_item(ilh_tree, hf_interlink_version, tvb, offset, 2, ENC_LITTLE_ENDIAN);
  84                 offset += 2;
  85                 proto_tree_add_item(ilh_tree, hf_interlink_cmd, tvb, offset, 2, ENC_LITTLE_ENDIAN);
  86                 offset += 2;
  87                 proto_tree_add_item(ilh_tree, hf_interlink_seq, tvb, offset, 2, ENC_LITTLE_ENDIAN);
  88                 offset += 2;
  89         } else {
  90                 offset += 10;
  91         }
  92
  93         if (ilh_tree) {
  94                 static const int * flags[] = {
  95                         &hf_interlink_flags_req_ack,
  96                         &hf_interlink_flags_inc_ack_port,
  97                         NULL
  98                 };
  99
 100                 proto_tree_add_bitmask(ilh_tree, tvb, offset, hf_interlink_flags, ett_interlink_flags, flags, ENC_LITTLE_ENDIAN);
 101
 102         }
 103         offset += 2;
 104
 105         ilb_tree = proto_tree_add_subtree(il_tree, tvb, offset, 4, ett_interlink_block, NULL, "Block Header");
 106
 107         ilb_type = tvb_get_guint8(tvb, offset);
 108         ilb_version = tvb_get_guint8(tvb, offset + 1);
 109         type_version = ilb_type << 8 | ilb_version;
 110         col_append_fstr(pinfo->cinfo, COL_INFO, "Type: %d, Version: %d",
 111                 ilb_type, ilb_version);
 112
 113         if (ilb_tree) {
 114                 proto_tree_add_item(ilb_tree, hf_interlink_block_type, tvb, offset, 1, ENC_BIG_ENDIAN);
 115                 offset += 1;
 116                 proto_tree_add_item(ilb_tree, hf_interlink_block_version, tvb, offset, 1, ENC_BIG_ENDIAN);
 117                 offset += 1;
 118                 proto_tree_add_item(ilb_tree, hf_interlink_block_length, tvb, offset, 2, ENC_LITTLE_ENDIAN);
 119                 offset += 2;
 120         } else {
 121                 offset += 4;
 122         }
 123
 124         /* Generate a new tvb for the rest. */
 125         next_tvb = tvb_new_subset_remaining(tvb, offset);
 126
 127         /* Probably a sub-dissector exists for this type/version combination. */
 128         handle = dissector_get_uint_handle(subdissector_table, type_version);
 129
 130         /* Without a proper sub-dissector, we use "data". */
 131         if (handle == NULL) handle = data_handle;
 132
 133         /* Call the sub-dissector. */
 134         call_dissector(handle, next_tvb, pinfo, tree);
 135
 136         return tvb_captured_length(tvb);
 137 }
 138
 139
 140 static gboolean
 141 dissect_interlink_heur(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void *data _U_)
 142 {
 143         if (!tvb_bytes_exist(tvb, 0, 4)) {
 144                 return FALSE;
 145         }
 146         if (
 147                 tvb_get_guint8(tvb,0) != 'I' ||
 148                 tvb_get_guint8(tvb,1) != 'L' ||
 149                 tvb_get_guint8(tvb,2) != 'N' ||
 150                 tvb_get_guint8(tvb,3) != 'K'
 151         )
 152                 return FALSE;
 153
 154         dissect_interlink(tvb, pinfo, tree, data);
 155         return TRUE;
 156 }
 157
 158
 159 void
 160 proto_register_interlink(void)
 161 {
 162         static hf_register_info hf[] = {
 163                 { &hf_interlink_id, {
 164                         "Magic ID", "interlink.id", FT_STRING,
 165                         BASE_NONE, NULL, 0, NULL, HFILL }},
 166                 { &hf_interlink_version, {
 167                         "Version", "interlink.version", FT_UINT16,
 168                         BASE_DEC, NULL, 0, NULL, HFILL }},
 169                 { &hf_interlink_cmd, {
 170                         "Command", "interlink.cmd", FT_UINT16,
 171                         BASE_DEC, VALS(names_cmd), 0, NULL, HFILL }},
 172                 { &hf_interlink_seq, {
 173                         "Sequence", "interlink.seq", FT_UINT16,
 174                         BASE_DEC, NULL, 0, NULL, HFILL }},
 175                 { &hf_interlink_flags, {
 176                         "Flags", "interlink.flags", FT_UINT16,
 177                         BASE_HEX, NULL, 0, NULL, HFILL }},
 178                 { &hf_interlink_flags_req_ack, {
 179                         "REQ_ACK", "interlink.flags.req_ack", FT_BOOLEAN,
 180                         16, TFS(&flags_set_notset), 0x01, NULL, HFILL }},
 181                 { &hf_interlink_flags_inc_ack_port, {
 182                         "INC_ACK_PORT", "interlink.flags.inc_ack_port", FT_BOOLEAN,
 183                         16, TFS(&flags_set_notset), 0x02, NULL, HFILL }},
 184                 { &hf_interlink_block_type, {
 185                         "Type", "interlink.type", FT_UINT8,
 186                         BASE_DEC, NULL, 0, NULL, HFILL }},
 187                 { &hf_interlink_block_version, {
 188                         "Version", "interlink.block_version", FT_UINT8,
 189                         BASE_DEC, NULL, 0, NULL, HFILL }},
 190                 { &hf_interlink_block_length, {
 191                         "Length", "interlink.length", FT_UINT16,
 192                         BASE_DEC, NULL, 0, NULL, HFILL }},
 193         };
 194
 195         static gint *ett[] = {
 196                 &ett_interlink,
 197                 &ett_interlink_header,
 198                 &ett_interlink_flags,
 199                 &ett_interlink_block,
 200         };
 201
 202         proto_interlink = proto_register_protocol("Interlink Protocol",
 203                                                         "Interlink",
 204                                                         "interlink");
 205         proto_register_field_array(proto_interlink, hf, array_length(hf));
 206         proto_register_subtree_array(ett, array_length(ett));
 207         interlink_handle = register_dissector("interlink", dissect_interlink, proto_interlink);
 208
 209         /* Probably someone will write sub-dissectors. You can never know. */
 210         subdissector_table = register_dissector_table("interlink.type_version",
 211                 "Interlink type_version", proto_interlink, FT_UINT16, BASE_HEX);
 212 }
 213
 214
 215 void
 216 proto_reg_handoff_interlink(void)
 217 {
 218         /* Allow "Decode As" with any UDP packet. */
 219         dissector_add_for_decode_as_with_preference("udp.port", interlink_handle);
 220
 221         /* Add our heuristic packet finder. */
 222         heur_dissector_add("udp", dissect_interlink_heur, "Interlink over UDP", "interlink_udp", proto_interlink, HEURISTIC_ENABLE);
 223
 224         data_handle = find_dissector("data");
 225 }
 226
 227 /*
 228  * Editor modelines  -  http://www.wireshark.org/tools/modelines.html
 229  *
 230  * Local variables:
 231  * c-basic-offset: 8
 232  * tab-width: 8
 233  * indent-tabs-mode: t
 234  * End:
 235  *
 236  * vi: set shiftwidth=8 tabstop=8 noexpandtab:
 237  * :indentSize=8:tabSize=8:noTabs=false:
 238  */