epan/dissectors/packet-laplink.c

   1 /* packet-laplink.c
   2  * Routines for laplink dissection
   3  * Copyright 2003, Brad Hards <bradh@frogmouth.net>
   4  *
   5  * $Id$
   6  *
   7  * Wireshark - Network traffic analyzer
   8  * By Gerald Combs <gerald@wireshark.org>
   9  * Copyright 1998 Gerald Combs
  10  *
  11  * This program is free software; you can redistribute it and/or
  12  * modify it under the terms of the GNU General Public License
  13  * as published by the Free Software Foundation; either version 2
  14  * of the License, or (at your option) any later version.
  15  *
  16  * This program is distributed in the hope that it will be useful,
  17  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  18  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  19  * GNU General Public License for more details.
  20  *
  21  * You should have received a copy of the GNU General Public License
  22  * along with this program; if not, write to the Free Software
  23  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  24  */
  25
  26 #include "config.h"
  27
  28 #include <glib.h>
  29
  30 #include <epan/packet.h>
  31 #include <epan/strutil.h>
  32
  33 #include "packet-tcp.h"
  34 #include <epan/prefs.h>
  35
  36 #define TCP_PORT_LAPLINK 1547
  37 #define UDP_PORT_LAPLINK 1547
  38
  39 /* Initialize the protocol and registered fields */
  40 static int proto_laplink = -1;
  41 static int hf_laplink_udp_ident = -1;
  42 static int hf_laplink_udp_name = -1;
  43 static int hf_laplink_tcp_ident = -1;
  44 static int hf_laplink_tcp_length = -1;
  45 static int hf_laplink_tcp_data = -1;
  46
  47 /* Initialize the subtree pointers */
  48 static gint ett_laplink = -1;
  49
  50 static const value_string laplink_udp_magic[] = {
  51         { 0x0f010000, "Name Solicitation" },
  52         { 0xf0000200, "Name Reply" },
  53         { 0, NULL }
  54 };
  55
  56 static const value_string laplink_tcp_magic[] = {
  57         { 0xff08c000, "Unknown TCP query - connection?" },
  58         { 0xff08c200, "Unknown TCP query - connection?" },
  59         { 0xff0bc000, "Unknown TCP query - connection?" },
  60         { 0xff0bc200, "Unknown TCP query - connection?" },
  61         { 0xff10c000, "Unknown TCP response - connection?" },
  62         { 0xff10c200, "Unknown TCP response - connection?" },
  63         { 0xff11c000, "Unknown TCP query/response - directory list or file transfer?" },
  64         { 0xff11c200, "Unknown TCP query - directory list or file request?" },
  65         { 0xff13c000, "Unknown TCP response - connection?" },
  66         { 0xff13c200, "Unknown TCP response - connection?" },
  67         { 0xff14c000, "Unknown TCP response - directory list or file transfer?" },
  68         { 0, NULL }
  69 };
  70
  71 static gboolean laplink_desegment = TRUE;
  72
  73 /* Code to actually dissect the packets - UDP */
  74 static gint
  75 dissect_laplink_udp(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void *data _U_)
  76 {
  77         int offset = 0;
  78         proto_item *ti;
  79         proto_tree *laplink_tree;
  80         guint32 udp_ident;
  81         const gchar *udp_ident_string;
  82
  83         /*
  84          * Make sure the identifier is reasonable.
  85          */
  86         if (!tvb_bytes_exist(tvb, offset, 4))
  87                 return 0;       /* not enough bytes to check */
  88         udp_ident = tvb_get_ntohl(tvb, offset);
  89         udp_ident_string = try_val_to_str(udp_ident, laplink_udp_magic);
  90         if (udp_ident_string == NULL)
  91                 return 0;       /* unknown */
  92
  93 /* Make entries in Protocol column and Info column on summary display */
  94         col_set_str(pinfo->cinfo, COL_PROTOCOL, "Laplink");
  95
  96         col_add_str(pinfo->cinfo, COL_INFO, udp_ident_string);
  97
  98         if (tree){
  99                 ti = proto_tree_add_item(tree, proto_laplink, tvb, 0, -1, ENC_NA);
 100                 laplink_tree = proto_item_add_subtree(ti, ett_laplink);
 101
 102                 proto_tree_add_uint(laplink_tree, hf_laplink_udp_ident, tvb, offset, 4, udp_ident);
 103                 offset += 4;
 104
 105                 proto_tree_add_item(laplink_tree, hf_laplink_udp_name, tvb, offset, -1, ENC_ASCII|ENC_NA);
 106         }
 107         return tvb_length(tvb);
 108 }
 109
 110 /* Code to actually dissect the packets - TCP aspects*/
 111 static int
 112 dissect_laplink_tcp_pdu(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void* data _U_)
 113 {
 114         int offset = 0;
 115         int length = 0;
 116         proto_item *ti;
 117         proto_tree *laplink_tree;
 118         guint32 tcp_ident;
 119
 120 /* Make entries in Protocol column and Info column on summary display */
 121         col_set_str(pinfo->cinfo, COL_PROTOCOL, "Laplink");
 122
 123         tcp_ident = tvb_get_ntohl(tvb, offset);
 124         col_add_str(pinfo->cinfo, COL_INFO,
 125                             val_to_str(tcp_ident, laplink_tcp_magic, "TCP TBA (%u)"));
 126
 127         if (tree){
 128                 ti = proto_tree_add_item(tree, proto_laplink, tvb, 0, -1, ENC_NA);
 129
 130
 131                 laplink_tree = proto_item_add_subtree(ti, ett_laplink);
 132
 133                 proto_tree_add_item(laplink_tree, hf_laplink_tcp_ident, tvb, offset, 4, ENC_BIG_ENDIAN);
 134                 offset += 4;
 135
 136                 length = tvb_get_ntohs(tvb, offset);
 137                 proto_tree_add_item(laplink_tree, hf_laplink_tcp_length, tvb, offset, 2, ENC_BIG_ENDIAN);
 138                 offset += 2;
 139
 140                 proto_tree_add_item(laplink_tree, hf_laplink_tcp_data, tvb, offset, length, ENC_NA);
 141
 142 /* Continue adding tree items to process the packet here */
 143
 144         }
 145
 146         return tvb_length(tvb);
 147 /* If this protocol has a sub-dissector call it here, see section 1.8 */
 148 }
 149
 150 static guint
 151 get_laplink_pdu_len(packet_info *pinfo _U_, tvbuff_t *tvb, int offset)
 152 {
 153         guint plen;
 154         /*
 155          * The length doesn't include the length or ident fields; add those in.
 156          */
 157         plen = (tvb_get_ntohs(tvb, offset+4) + 2 + 4);
 158         return plen;
 159 }
 160
 161 static int
 162 dissect_laplink_tcp(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void* data)
 163 {
 164         tcp_dissect_pdus(tvb, pinfo, tree, laplink_desegment,
 165                          6, get_laplink_pdu_len,
 166                          dissect_laplink_tcp_pdu, data);
 167         return tvb_length(tvb);
 168 }
 169
 170
 171 /* Register the protocol with Wireshark */
 172
 173 void
 174 proto_register_laplink(void)
 175 {
 176
 177 /* Setup list of header fields  See Section 1.6.1 for details*/
 178         static hf_register_info hf[] = {
 179                 { &hf_laplink_udp_ident,
 180                         { "UDP Ident", "laplink.udp_ident",
 181                         FT_UINT32, BASE_HEX, VALS(laplink_udp_magic), 0x0,
 182                         "Unknown magic", HFILL }
 183                 },
 184                 { &hf_laplink_udp_name,
 185                         { "UDP Name", "laplink.udp_name",
 186                         FT_STRINGZ, BASE_NONE, NULL, 0x0,
 187                         "Machine name", HFILL }
 188                 },
 189                 { &hf_laplink_tcp_ident,
 190                         { "TCP Ident", "laplink.tcp_ident",
 191                         FT_UINT32, BASE_HEX, VALS(laplink_tcp_magic), 0x0,
 192                         "Unknown magic", HFILL }
 193                 },
 194                 { &hf_laplink_tcp_length,
 195                         { "TCP Data payload length", "laplink.tcp_length",
 196                         FT_UINT16, BASE_DEC, NULL, 0x0,
 197                         "Length of remaining payload", HFILL }
 198                 },
 199                 { &hf_laplink_tcp_data,
 200                         { "Unknown TCP data", "laplink.tcp_data",
 201                         FT_BYTES, BASE_NONE, NULL, 0x0,
 202                         "TCP data", HFILL }
 203                 },
 204         };
 205
 206 /* Setup protocol subtree array */
 207         static gint *ett[] = {
 208                 &ett_laplink,
 209         };
 210
 211         module_t *laplink_module;
 212
 213 /* Register the protocol name and description */
 214         proto_laplink = proto_register_protocol("Laplink",
 215             "Laplink", "laplink");
 216
 217 /* Required function calls to register the header fields and subtrees used */
 218         proto_register_field_array(proto_laplink, hf, array_length(hf));
 219         proto_register_subtree_array(ett, array_length(ett));
 220
 221         laplink_module = prefs_register_protocol(proto_laplink, NULL);
 222         prefs_register_bool_preference(laplink_module, "desegment_laplink_over_tcp",
 223                                        "Reassemble Laplink over TCP messages spanning multiple TCP segments",
 224                                        "Whether the Laplink dissector should reassemble messages spanning multiple TCP segments."
 225                                        " To use this option, you must also enable \"Allow subdissectors to reassemble TCP streams\" in the TCP protocol settings.",
 226                                        &laplink_desegment);
 227 }
 228
 229
 230 /* If this dissector uses sub-dissector registration add a registration routine.
 231    This format is required because a script is used to find these routines and
 232    create the code that calls these routines.
 233 */
 234 void
 235 proto_reg_handoff_laplink(void)
 236 {
 237         dissector_handle_t laplink_udp_handle;
 238         dissector_handle_t laplink_tcp_handle;
 239
 240         laplink_tcp_handle = new_create_dissector_handle(dissect_laplink_tcp,
 241             proto_laplink);
 242         dissector_add_uint("tcp.port", TCP_PORT_LAPLINK, laplink_tcp_handle);
 243
 244         laplink_udp_handle = new_create_dissector_handle(dissect_laplink_udp,
 245             proto_laplink);
 246         dissector_add_uint("udp.port", UDP_PORT_LAPLINK, laplink_udp_handle);
 247 }
 248