epan/dissectors/packet-bpq.c

   1 /* packet-bpq.c
   2  *
   3  * Routines for Amateur Packet Radio protocol dissection
   4  * Copyright 2005,2006,2007,2008,2009,2010,2012 R.W. Stearn <richard@rns-stearn.demon.co.uk>
   5  *
   6  * $Id$
   7  *
   8  * Wireshark - Network traffic analyzer
   9  * By Gerald Combs <gerald@wireshark.org>
  10  * Copyright 1998 Gerald Combs
  11  *
  12  * This program is free software; you can redistribute it and/or
  13  * modify it under the terms of the GNU General Public License
  14  * as published by the Free Software Foundation; either version 2
  15  * of the License, or (at your option) any later version.
  16  *
  17  * This program is distributed in the hope that it will be useful,
  18  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  19  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  20  * GNU General Public License for more details.
  21  *
  22  * You should have received a copy of the GNU General Public License
  23  * along with this program; if not, write to the Free Software
  24  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  25  */
  26
  27 /*
  28  * This dissector is for:
  29  *   Ethernet encapsulated Amateur AX.25 (AX.25 over Ethernet)
  30  *
  31  * Information was drawn from:
  32  *   ?
  33  *
  34  * It uses Ether ID 0x08ff which is not not officially registered.
  35  *
  36  */
  37
  38 #include "config.h"
  39
  40 #include <glib.h>
  41
  42 #include <epan/packet.h>
  43 #include <epan/etypes.h>
  44
  45 #include "packet-bpq.h"
  46 #include "packet-ax25.h"
  47
  48 #define STRLEN  80
  49
  50 #define BPQ_HEADER_SIZE 2 /* length of bpq_len */
  51
  52 void proto_register_bpq(void);
  53 void proto_reg_handoff_bpq(void);
  54
  55 static dissector_handle_t ax25_handle;
  56
  57 static int proto_bpq            = -1;
  58 static int hf_bpq_len           = -1;
  59
  60 static gint ett_bpq = -1;
  61
  62 static void
  63 dissect_bpq( tvbuff_t *tvb, packet_info *pinfo, proto_tree *parent_tree )
  64 {
  65         proto_item *ti;
  66         proto_tree *bpq_tree;
  67         int         offset;
  68         guint16     bpq_len;
  69         tvbuff_t   *next_tvb;
  70
  71
  72         col_set_str( pinfo->cinfo, COL_PROTOCOL, "BPQ" );
  73
  74         col_clear( pinfo->cinfo, COL_INFO );
  75
  76         /* protocol offset for the BPQ header */
  77         offset = 0;
  78
  79         bpq_len = tvb_get_letohs( tvb, offset );
  80
  81         col_add_fstr( pinfo->cinfo, COL_INFO, "%u", bpq_len );
  82
  83         if ( parent_tree )
  84                 {
  85                 /* protocol offset for the BPQ header */
  86                 offset = 0;
  87
  88                 /* create display subtree for the protocol */
  89                 ti = proto_tree_add_protocol_format( parent_tree, proto_bpq, tvb, offset, BPQ_HEADER_SIZE,
  90                         "BPQ, Len: %u",
  91                         bpq_len & 0xfff /* XXX - lower 12 bits? */
  92                         );
  93
  94                 bpq_tree = proto_item_add_subtree( ti, ett_bpq );
  95
  96                 proto_tree_add_item( bpq_tree, hf_bpq_len, tvb, offset, BPQ_HEADER_SIZE, ENC_LITTLE_ENDIAN );
  97
  98         }
  99
 100         offset += BPQ_HEADER_SIZE;
 101
 102         /* XXX - use the length */
 103         next_tvb = tvb_new_subset_remaining( tvb, offset );
 104         call_dissector( ax25_handle, next_tvb, pinfo, parent_tree );
 105 }
 106
 107 void
 108 capture_bpq( const guchar *pd, int offset, int len, packet_counts *ld)
 109 {
 110         int l_offset;
 111
 112         if ( ! BYTES_ARE_IN_FRAME( offset, len, BPQ_HEADER_SIZE ) )
 113                 {
 114                 ld->other++;
 115                 return;
 116                 }
 117
 118         l_offset = offset;
 119         l_offset += BPQ_HEADER_SIZE; /* step over bpq header to point at the AX.25 packet*/
 120         capture_ax25( pd, l_offset, len, ld );
 121 }
 122
 123 void
 124 proto_register_bpq(void)
 125 {
 126         /* Setup list of header fields */
 127         static hf_register_info hf[] = {
 128                 { &hf_bpq_len,
 129                         { "BPQ len",                    "bpq.len",
 130                         FT_UINT16, BASE_DEC, NULL, 0x0,
 131                         NULL, HFILL }
 132                 },
 133         };
 134
 135         /* Setup protocol subtree array */
 136         static gint *ett[] = {
 137                 &ett_bpq,
 138         };
 139
 140         /* Register the protocol name and description */
 141         proto_bpq = proto_register_protocol( "Amateur Radio BPQ", "BPQ", "bpq" );
 142
 143         /* Register the dissector */
 144         register_dissector( "bpq", dissect_bpq, proto_bpq );
 145
 146         /* Required function calls to register the header fields and subtrees used */
 147         proto_register_field_array( proto_bpq, hf, array_length( hf ) );
 148         proto_register_subtree_array( ett, array_length( ett ) );
 149 }
 150
 151 void
 152 proto_reg_handoff_bpq(void)
 153 {
 154         dissector_handle_t bpq_handle;
 155
 156         bpq_handle = create_dissector_handle( dissect_bpq, proto_bpq );
 157         dissector_add_uint("ethertype", ETHERTYPE_BPQ, bpq_handle);
 158
 159         /* BPQ is only implemented for AX.25 */
 160         ax25_handle     = find_dissector( "ax25" );
 161
 162 }