forked from osmocom/wireshark
d47551982b
Mirror it after protocol dissector API. Change-Id: I7985bcfa9e07654c7cf005efec94efc205d7a304 Reviewed-on: https://code.wireshark.org/review/18496 Reviewed-by: Michael Mann <mmann78@netscape.net>
440 lines
12 KiB
C
440 lines
12 KiB
C
/* packet-ax25.c
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*
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* Routines for Amateur Packet Radio protocol dissection
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* AX.25 frames
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* Copyright 2005,2006,2007,2008,2009,2010,2012 R.W. Stearn <richard@rns-stearn.demon.co.uk>
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*
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* Wireshark - Network traffic analyzer
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* By Gerald Combs <gerald@wireshark.org>
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* Copyright 1998 Gerald Combs
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version 2
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* of the License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
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*/
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/*
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* This dissector is for:
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* AX.25 Amateur Packet-Radio Link-Layer Protocol, Version 2.0, October 1984
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*
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* At the time of writing the specification could be found here:
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* http://www.tapr.org/pub_ax25.html
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*
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* A newer version, Version 2.2, July 1998, can be found at
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* http://www.ax25.net/AX25.2.2-Jul%2098-2.pdf
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*
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* Inspiration on how to build the dissector drawn from
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* packet-sdlc.c
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* packet-x25.c
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* packet-lapb.c
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* paket-gprs-llc.c
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* xdlc.c
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* with the base file built from README.developers.
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*/
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#include "config.h"
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#include <epan/packet.h>
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#include <epan/capture_dissectors.h>
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#include <wiretap/wtap.h>
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#include <epan/to_str.h>
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#include <epan/xdlc.h>
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#include <epan/ax25_pids.h>
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#include <epan/ipproto.h>
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#define STRLEN 80
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#define AX25_HEADER_SIZE 15 /* length of src_addr + dst_addr + cntl */
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#define AX25_MAX_DIGIS 8
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void proto_register_ax25(void);
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void proto_reg_handoff_ax25(void);
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/* Dissector table */
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static dissector_table_t ax25_dissector_table;
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static capture_dissector_handle_t ax25_cap_handle;
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/* Initialize the protocol and registered fields */
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static int proto_ax25 = -1;
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static int hf_ax25_dst = -1;
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static int hf_ax25_src = -1;
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static int hf_ax25_via[ AX25_MAX_DIGIS ] = { -1,-1,-1,-1,-1,-1,-1,-1 };
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static int hf_ax25_ctl = -1;
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static int hf_ax25_n_r = -1;
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static int hf_ax25_n_s = -1;
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static int hf_ax25_p = -1;
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static int hf_ax25_f = -1;
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static int hf_ax25_ftype_s = -1;
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static int hf_ax25_ftype_i = -1;
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static int hf_ax25_ftype_su = -1;
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static int hf_ax25_u_cmd = -1;
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static int hf_ax25_u_resp = -1;
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static int hf_ax25_pid = -1;
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static const xdlc_cf_items ax25_cf_items = {
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&hf_ax25_n_r,
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&hf_ax25_n_s,
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&hf_ax25_p,
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&hf_ax25_f,
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&hf_ax25_ftype_s,
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&hf_ax25_u_cmd,
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&hf_ax25_u_resp,
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&hf_ax25_ftype_i,
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&hf_ax25_ftype_su
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};
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static const value_string pid_vals[] = {
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{ AX25_P_ROSE, "Rose" },
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{ AX25_P_RFC1144C, "RFC1144 (compressed)" },
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{ AX25_P_RFC1144, "RFC1144 (uncompressed)" },
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{ AX25_P_SEGMENT, "Segment" },
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{ AX25_P_TEXNET, "Texnet" },
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{ AX25_P_LCP, "Link Quality protocol" },
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{ AX25_P_ATALK, "AppleTalk" },
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{ AX25_P_ATALKARP, "AppleTalk ARP" },
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{ AX25_P_IP, "IP" },
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{ AX25_P_ARP, "ARP" },
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{ AX25_P_FLEXNET, "FlexNet" },
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{ AX25_P_NETROM, "NetRom" },
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{ AX25_P_NO_L3, "No L3" },
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{ AX25_P_L3_ESC, "L3 esc" },
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{ 0, NULL }
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};
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static gint ett_ax25 = -1;
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static gint ett_ax25_ctl = -1;
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static dissector_handle_t ax25_handle;
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static int
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dissect_ax25( tvbuff_t *tvb, packet_info *pinfo, proto_tree *parent_tree, void* data _U_ )
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{
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proto_item *ti;
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proto_tree *ax25_tree;
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int offset;
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int via_index;
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char *info_buffer;
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/* char v2cmdresp; */
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const char *ax25_version;
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int is_response;
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guint8 control;
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guint8 pid = AX25_P_NO_L3;
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guint8 src_ssid;
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guint8 dst_ssid;
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tvbuff_t *next_tvb = NULL;
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info_buffer = (char *)wmem_alloc( wmem_packet_scope(), STRLEN );
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info_buffer[0] = '\0';
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col_set_str( pinfo->cinfo, COL_PROTOCOL, "AX.25" );
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col_clear( pinfo->cinfo, COL_INFO );
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/* start at the dst addr */
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offset = 0;
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/* create display subtree for the protocol */
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ti = proto_tree_add_protocol_format( parent_tree, proto_ax25, tvb, offset, -1, "AX.25");
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ax25_tree = proto_item_add_subtree( ti, ett_ax25 );
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proto_tree_add_item( ax25_tree, hf_ax25_dst, tvb, offset, AX25_ADDR_LEN, ENC_NA);
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set_address_tvb(&pinfo->dl_dst, AT_AX25, AX25_ADDR_LEN, tvb, offset);
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copy_address_shallow(&pinfo->dst, &pinfo->dl_dst);
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dst_ssid = tvb_get_guint8(tvb, offset+6);
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/* step over dst addr point at src addr */
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offset += AX25_ADDR_LEN;
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proto_tree_add_item( ax25_tree, hf_ax25_src, tvb, offset, AX25_ADDR_LEN, ENC_NA);
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set_address_tvb(&pinfo->dl_src, AT_AX25, AX25_ADDR_LEN, tvb, offset);
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copy_address_shallow(&pinfo->src, &pinfo->dl_src);
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src_ssid = tvb_get_guint8(tvb, offset+6);
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/* step over src addr point at either 1st via addr or control byte */
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offset += AX25_ADDR_LEN;
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proto_item_append_text( ti, ", Src: %s, Dst: %s",
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address_to_str(wmem_packet_scope(), &pinfo->src),
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address_to_str(wmem_packet_scope(), &pinfo->dst));
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/* decode the cmd/resp field */
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/* v2cmdresp = '.'; */
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switch ( ( (dst_ssid >> 6) & 0x02) | ( (src_ssid >> 7) & 0x01 ) )
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{
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case 1 : /* V2.0 Response */
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ax25_version = "V2.0+";
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/* v2cmdresp = 'R'; */
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is_response = TRUE;
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break;
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case 2 : /* V2.0 Command */
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ax25_version = "V2.0+";
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/* v2cmdresp = 'C'; */
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is_response = FALSE;
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break;
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default :
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ax25_version = "V?.?";
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/* v2cmdresp = '?'; */
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is_response = FALSE;
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break;
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}
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proto_item_append_text( ti, ", Ver: %s", ax25_version );
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/* handle the vias, if any */
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via_index = 0;
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while ( ( tvb_get_guint8( tvb, offset - 1 ) & 0x01 ) == 0 )
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{
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if ( via_index < AX25_MAX_DIGIS )
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{
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proto_tree_add_item( ax25_tree, hf_ax25_via[ via_index ], tvb, offset, AX25_ADDR_LEN, ENC_NA);
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via_index++;
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}
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/* step over a via addr */
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offset += AX25_ADDR_LEN;
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}
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/* XXX - next-to-last argument should be TRUE if modulo 128 operation */
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control = dissect_xdlc_control( tvb,
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offset,
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pinfo,
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ax25_tree,
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hf_ax25_ctl,
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ett_ax25_ctl,
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&ax25_cf_items,
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NULL,
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NULL,
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NULL,
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is_response,
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FALSE,
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FALSE );
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/* XXX - second argument should be TRUE if modulo 128 operation */
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offset += XDLC_CONTROL_LEN(control, FALSE); /* step over control field */
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if ( XDLC_IS_INFORMATION( control ) )
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{
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pid = tvb_get_guint8( tvb, offset );
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col_append_fstr( pinfo->cinfo, COL_INFO, ", %s", val_to_str(pid, pid_vals, "Unknown (0x%02x)") );
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proto_tree_add_uint( ax25_tree, hf_ax25_pid, tvb, offset, 1, pid );
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/* Call sub-dissectors here */
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offset += 1; /* step over pid to the 1st byte of the payload */
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proto_item_set_end(ti, tvb, offset);
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next_tvb = tvb_new_subset_remaining(tvb, offset);
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if (!dissector_try_uint(ax25_dissector_table, pid, next_tvb, pinfo, parent_tree))
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{
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call_data_dissector(next_tvb, pinfo, parent_tree);
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}
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}
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else
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proto_item_set_end(ti, tvb, offset);
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return tvb_captured_length(tvb);
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}
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gboolean
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capture_ax25( const guchar *pd, int offset, int len, capture_packet_info_t *cpinfo, const union wtap_pseudo_header *pseudo_header)
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{
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guint8 control;
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guint8 pid;
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int l_offset;
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if ( ! BYTES_ARE_IN_FRAME( offset, len, AX25_HEADER_SIZE ) )
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return FALSE;
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l_offset = offset;
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l_offset += AX25_ADDR_LEN; /* step over dst addr point at src addr */
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l_offset += AX25_ADDR_LEN; /* step over src addr point at either 1st via addr or control byte */
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while ( ( pd[ l_offset - 1 ] & 0x01 ) == 0 )
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l_offset += AX25_ADDR_LEN; /* step over a via addr */
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control = pd[ l_offset ];
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/* decode the pid field (if appropriate) */
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if ( XDLC_IS_INFORMATION( control ) )
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{
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l_offset += 1; /* step over control byte point at pid */
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pid = pd[ l_offset ];
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l_offset += 1; /* step over the pid and point to the first byte of the payload */
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return try_capture_dissector("ax25.pid", pid & 0x0ff, pd, l_offset, len, cpinfo, pseudo_header);
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}
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return FALSE;
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}
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void
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proto_register_ax25(void)
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{
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/* Setup list of header fields */
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static hf_register_info hf[] = {
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{ &hf_ax25_dst,
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{ "Destination", "ax25.dst",
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FT_AX25, BASE_NONE, NULL, 0x0,
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"Destination callsign", HFILL }
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},
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{ &hf_ax25_src,
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{ "Source", "ax25.src",
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FT_AX25, BASE_NONE, NULL, 0x0,
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"Source callsign", HFILL }
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},
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{ &hf_ax25_via[ 0 ],
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{ "Via 1", "ax25.via1",
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FT_AX25, BASE_NONE, NULL, 0x0,
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"Via callsign 1", HFILL }
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},
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{ &hf_ax25_via[ 1 ],
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{ "Via 2", "ax25.via2",
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FT_AX25, BASE_NONE, NULL, 0x0,
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"Via callsign 2", HFILL }
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},
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{ &hf_ax25_via[ 2 ],
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{ "Via 3", "ax25.via3",
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FT_AX25, BASE_NONE, NULL, 0x0,
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"Via callsign 3", HFILL }
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},
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{ &hf_ax25_via[ 3 ],
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{ "Via 4", "ax25.via4",
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FT_AX25, BASE_NONE, NULL, 0x0,
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"Via callsign 4", HFILL }
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},
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{ &hf_ax25_via[ 4 ],
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{ "Via 5", "ax25.via5",
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FT_AX25, BASE_NONE, NULL, 0x0,
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"Via callsign 5", HFILL }
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},
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{ &hf_ax25_via[ 5 ],
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{ "Via 6", "ax25.via6",
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FT_AX25, BASE_NONE, NULL, 0x0,
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"Via callsign 6", HFILL }
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},
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{ &hf_ax25_via[ 6 ],
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{ "Via 7", "ax25.via7",
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FT_AX25, BASE_NONE, NULL, 0x0,
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"Via callsign 7", HFILL }
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},
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{ &hf_ax25_via[ 7 ],
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{ "Via 8", "ax25.via8",
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FT_AX25, BASE_NONE, NULL, 0x0,
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"Via callsign 8", HFILL }
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},
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{ &hf_ax25_ctl,
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{ "Control", "ax25.ctl",
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FT_UINT8, BASE_HEX, NULL, 0x0,
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"Control field", HFILL }
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},
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{ &hf_ax25_n_r,
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{ "n(r)", "ax25.ctl.n_r",
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FT_UINT8, BASE_DEC, NULL, XDLC_N_R_MASK,
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NULL, HFILL }
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},
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{ &hf_ax25_n_s,
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{ "n(s)", "ax25.ctl.n_s",
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FT_UINT8, BASE_DEC, NULL, XDLC_N_S_MASK,
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NULL, HFILL }
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},
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{ &hf_ax25_p,
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{ "Poll", "ax25.ctl.p",
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FT_BOOLEAN, 8, TFS(&tfs_set_notset), XDLC_P_F,
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NULL, HFILL }
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},
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{ &hf_ax25_f,
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{ "Final", "ax25.ctl.f",
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FT_BOOLEAN, 8, TFS(&tfs_set_notset), XDLC_P_F,
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NULL, HFILL }
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},
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{ &hf_ax25_ftype_s,
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{ "Frame type", "ax25.ctl.ftype_s",
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FT_UINT8, BASE_HEX, VALS(stype_vals), XDLC_S_FTYPE_MASK,
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NULL, HFILL }
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},
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{ &hf_ax25_ftype_i,
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{ "Frame type", "ax25.ctl.ftype_i",
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FT_UINT8, BASE_HEX, VALS(ftype_vals), XDLC_I_MASK,
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NULL, HFILL }
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},
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{ &hf_ax25_ftype_su,
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{ "Frame type", "ax25.ctl.ftype_su",
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FT_UINT8, BASE_HEX, VALS(ftype_vals), XDLC_S_U_MASK,
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NULL, HFILL }
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},
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{ &hf_ax25_u_cmd,
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{ "Frame type", "ax25.ctl.u_cmd",
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FT_UINT8, BASE_HEX, VALS(modifier_vals_cmd), XDLC_U_MODIFIER_MASK,
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NULL, HFILL }
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},
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{ &hf_ax25_u_resp,
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{ "Frame type", "ax25.ctl.u_resp",
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FT_UINT8, BASE_HEX, VALS(modifier_vals_resp), XDLC_U_MODIFIER_MASK,
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NULL, HFILL }
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},
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{ &hf_ax25_pid,
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{ "Protocol ID", "ax25.pid",
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FT_UINT8, BASE_HEX, VALS(pid_vals), 0x0,
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"Protocol identifier", HFILL }
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},
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};
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/* Setup protocol subtree array */
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static gint *ett[] = {
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&ett_ax25,
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&ett_ax25_ctl,
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};
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/* Register the protocol name and description */
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proto_ax25 = proto_register_protocol("Amateur Radio AX.25", "AX.25", "ax25");
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/* Register the dissector */
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ax25_handle = register_dissector( "ax25", dissect_ax25, proto_ax25 );
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/* Required function calls to register the header fields and subtrees used */
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proto_register_field_array( proto_ax25, hf, array_length(hf ) );
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proto_register_subtree_array(ett, array_length(ett ) );
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/* Register dissector table for protocol IDs */
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ax25_dissector_table = register_dissector_table("ax25.pid", "AX.25 protocol ID", proto_ax25, FT_UINT8, BASE_HEX);
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register_capture_dissector_table("ax25.pid", "AX.25");
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ax25_cap_handle = register_capture_dissector("ax25", capture_ax25, proto_ax25);
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}
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void
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proto_reg_handoff_ax25(void)
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{
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dissector_add_uint("wtap_encap", WTAP_ENCAP_AX25, ax25_handle);
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dissector_add_uint("ip.proto", IP_PROTO_AX25, ax25_handle);
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capture_dissector_add_uint("wtap_encap", WTAP_ENCAP_AX25, ax25_cap_handle);
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}
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/*
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* Editor modelines - http://www.wireshark.org/tools/modelines.html
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*
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* Local variables:
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* c-basic-offset: 8
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* tab-width: 8
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* indent-tabs-mode: t
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* End:
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*
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* vi: set shiftwidth=8 tabstop=8 noexpandtab:
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* :indentSize=8:tabSize=8:noTabs=false:
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*/
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