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  * 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 /*
  14  * This dissector is for:
  15  *   Ethernet encapsulated Amateur AX.25 (AX.25 over Ethernet)
  16  *
  17  * Information was drawn from:
  18  *   ?
  19  *
  20  * It uses Ether ID 0x08ff which is not officially registered.
  21  *
  22  */
  23
  24 #include "config.h"
  25
  26 #include <epan/packet.h>
  27 #include <epan/etypes.h>
  28 #include <epan/capture_dissectors.h>
  29
  30 #define STRLEN  80
  31
  32 #define BPQ_HEADER_SIZE 2 /* length of bpq_len */
  33
  34 void proto_register_bpq(void);
  35 void proto_reg_handoff_bpq(void);
  36
  37 static dissector_handle_t bpq_handle;
  38 static dissector_handle_t ax25_handle;
  39
  40 static capture_dissector_handle_t ax25_cap_handle;
  41
  42 static int proto_bpq;
  43 static int hf_bpq_len;
  44
  45 static int ett_bpq;
  46
  47 static int
  48 dissect_bpq( tvbuff_t *tvb, packet_info *pinfo, proto_tree *parent_tree, void* data _U_ )
  49 {
  50         proto_item *ti;
  51         proto_tree *bpq_tree;
  52         int         offset;
  53         uint16_t            bpq_len;
  54         tvbuff_t   *next_tvb;
  55
  56
  57         col_set_str( pinfo->cinfo, COL_PROTOCOL, "BPQ" );
  58
  59         col_clear( pinfo->cinfo, COL_INFO );
  60
  61         /* protocol offset for the BPQ header */
  62         offset = 0;
  63
  64         bpq_len = tvb_get_letohs( tvb, offset );
  65
  66         col_add_fstr( pinfo->cinfo, COL_INFO, "%u", bpq_len );
  67
  68         if ( parent_tree )
  69                 {
  70                 /* protocol offset for the BPQ header */
  71                 offset = 0;
  72
  73                 /* create display subtree for the protocol */
  74                 ti = proto_tree_add_protocol_format( parent_tree, proto_bpq, tvb, offset, BPQ_HEADER_SIZE,
  75                         "BPQ, Len: %u",
  76                         bpq_len & 0xfff /* XXX - lower 12 bits? */
  77                         );
  78
  79                 bpq_tree = proto_item_add_subtree( ti, ett_bpq );
  80
  81                 proto_tree_add_item( bpq_tree, hf_bpq_len, tvb, offset, BPQ_HEADER_SIZE, ENC_LITTLE_ENDIAN );
  82
  83         }
  84
  85         offset += BPQ_HEADER_SIZE;
  86
  87         /* XXX - use the length */
  88         next_tvb = tvb_new_subset_remaining( tvb, offset );
  89         call_dissector( ax25_handle, next_tvb, pinfo, parent_tree );
  90         return tvb_captured_length(tvb);
  91 }
  92
  93 static bool
  94 capture_bpq( const unsigned char *pd, int offset, int len, capture_packet_info_t *cpinfo, const union wtap_pseudo_header *pseudo_header)
  95 {
  96         int l_offset;
  97
  98         if ( ! BYTES_ARE_IN_FRAME( offset, len, BPQ_HEADER_SIZE ) )
  99                 return false;
 100
 101         l_offset = offset;
 102         l_offset += BPQ_HEADER_SIZE; /* step over bpq header to point at the AX.25 packet*/
 103         return call_capture_dissector( ax25_cap_handle, pd, l_offset, len, cpinfo, pseudo_header );
 104 }
 105
 106 void
 107 proto_register_bpq(void)
 108 {
 109         /* Setup list of header fields */
 110         static hf_register_info hf[] = {
 111                 { &hf_bpq_len,
 112                         { "BPQ len",                    "bpq.len",
 113                         FT_UINT16, BASE_DEC, NULL, 0x0,
 114                         NULL, HFILL }
 115                 },
 116         };
 117
 118         /* Setup protocol subtree array */
 119         static int *ett[] = {
 120                 &ett_bpq,
 121         };
 122
 123         /* Register the protocol name and description */
 124         proto_bpq = proto_register_protocol( "Amateur Radio BPQ", "BPQ", "bpq" );
 125
 126         /* Register the dissector */
 127         bpq_handle = register_dissector("bpq", dissect_bpq, proto_bpq);
 128
 129         /* Required function calls to register the header fields and subtrees used */
 130         proto_register_field_array( proto_bpq, hf, array_length( hf ) );
 131         proto_register_subtree_array( ett, array_length( ett ) );
 132 }
 133
 134 void
 135 proto_reg_handoff_bpq(void)
 136 {
 137         capture_dissector_handle_t bpq_cap_handle;
 138
 139         dissector_add_uint("ethertype", ETHERTYPE_BPQ, bpq_handle);
 140         bpq_cap_handle = create_capture_dissector_handle(capture_bpq, proto_bpq);
 141         capture_dissector_add_uint("ethertype", ETHERTYPE_BPQ, bpq_cap_handle);
 142
 143         /* BPQ is only implemented for AX.25 */
 144         ax25_handle     = find_dissector_add_dependency( "ax25", proto_bpq );
 145
 146         ax25_cap_handle = find_capture_dissector( "ax25" );
 147 }
 148
 149 /*
 150  * Editor modelines  -  https://www.wireshark.org/tools/modelines.html
 151  *
 152  * Local variables:
 153  * c-basic-offset: 8
 154  * tab-width: 8
 155  * indent-tabs-mode: t
 156  * End:
 157  *
 158  * vi: set shiftwidth=8 tabstop=8 noexpandtab:
 159  * :indentSize=8:tabSize=8:noTabs=false:
 160  */