forked from osmocom/wireshark
![Jaap Keuter](/assets/img/avatar_default.png)
Take negative value into account, avoid all casting in the process. svn path=/trunk/; revision=47223
719 lines
23 KiB
C
719 lines
23 KiB
C
/* packet-lapd.c
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* Routines for LAPD frame disassembly
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* Gilbert Ramirez <gram@alumni.rice.edu>
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*
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* $Id$
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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
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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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* LAPD bitstream over RTP handling
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* Copyright 2008, Ericsson AB
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* Written by Balint Reczey <balint.reczey@ericsson.com>
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*
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* ISDN/LAPD references:
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*
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* http://www.cisco.com/univercd/cc/td/doc/cisintwk/ito_doc/isdn.htm
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* http://www.ece.wpi.edu/courses/ee535/hwk11cd95/agrebe/agrebe.html
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* http://www.acacia-net.com/Clarinet/Protocol/q9213o84.htm
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* http://www.itu.int/rec/T-REC-Q.921/en
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* Base Station Controller - Base Transceiver Station (BSC - BTS) interface; Layer 2 specification
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* http://www.3gpp.org/ftp/Specs/html-info/48056.htm
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*/
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#include "config.h"
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#include <glib.h>
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#include <string.h>
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#include <epan/packet.h>
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#include <epan/conversation.h>
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#include <epan/xdlc.h>
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#include <epan/crc16-tvb.h>
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#include <epan/prefs.h>
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#include <epan/lapd_sapi.h>
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static int proto_lapd = -1;
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static int hf_lapd_direction = -1;
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static int hf_lapd_address = -1;
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static int hf_lapd_sapi = -1;
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static int hf_lapd_gsm_sapi = -1;
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static int hf_lapd_cr = -1;
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static int hf_lapd_ea1 = -1;
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static int hf_lapd_tei = -1;
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static int hf_lapd_ea2 = -1;
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static int hf_lapd_control = -1;
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static int hf_lapd_n_r = -1;
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static int hf_lapd_n_s = -1;
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static int hf_lapd_p = -1;
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static int hf_lapd_p_ext = -1;
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static int hf_lapd_f = -1;
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static int hf_lapd_f_ext = -1;
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static int hf_lapd_s_ftype = -1;
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static int hf_lapd_u_modifier_cmd = -1;
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static int hf_lapd_u_modifier_resp = -1;
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static int hf_lapd_ftype_i = -1;
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static int hf_lapd_ftype_s_u = -1;
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static int hf_lapd_ftype_s_u_ext = -1;
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static int hf_lapd_checksum = -1;
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static int hf_lapd_checksum_good = -1;
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static int hf_lapd_checksum_bad = -1;
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static gint ett_lapd = -1;
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static gint ett_lapd_address = -1;
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static gint ett_lapd_control = -1;
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static gint ett_lapd_checksum = -1;
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static gint pref_lapd_rtp_payload_type = 0;
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static dissector_table_t lapd_sapi_dissector_table;
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static dissector_table_t lapd_gsm_sapi_dissector_table;
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/* Whether to use GSM SAPI vals or not */
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static gboolean global_lapd_gsm_sapis = FALSE;
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static dissector_handle_t data_handle;
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/*
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* Bits in the address field.
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*/
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#define LAPD_SAPI 0xfc00 /* Service Access Point Identifier */
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#define LAPD_SAPI_SHIFT 10
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#define LAPD_CR 0x0200 /* Command/Response bit */
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#define LAPD_EA1 0x0100 /* First Address Extension bit */
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#define LAPD_TEI 0x00fe /* Terminal Endpoint Identifier */
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#define LAPD_TEI_SHIFT 1
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#define LAPD_EA2 0x0001 /* Second Address Extension bit */
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static const value_string lapd_direction_vals[] = {
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{ P2P_DIR_RECV, "Network->User"},
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{ P2P_DIR_SENT, "User->Network"},
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{ 0, NULL }
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};
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static const value_string lapd_sapi_vals[] = {
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{ LAPD_SAPI_Q931, "Q.931 Call control procedure" },
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{ LAPD_SAPI_PM_Q931, "Packet mode Q.931 Call control procedure" },
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{ LAPD_SAPI_X25, "X.25 Level 3 procedures" },
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{ LAPD_SAPI_L2, "Layer 2 management procedures" },
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{ 0, NULL }
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};
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static const value_string lapd_gsm_sapi_vals[] = {
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{ LAPD_GSM_SAPI_RA_SIG_PROC, "Radio signalling procedures" },
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{ LAPD_GSM_SAPI_NOT_USED_1, "(Not used in GSM PLMN)" },
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{ LAPD_GSM_SAPI_NOT_USED_16, "(Not used in GSM PLMN)" },
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{ LAPD_GSM_SAPI_OM_PROC, "Operation and maintenance procedure" },
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{ LAPD_SAPI_L2, "Layer 2 management procedures" },
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{ 0, NULL }
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};
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/* Used only for U frames */
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static const xdlc_cf_items lapd_cf_items = {
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NULL,
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NULL,
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&hf_lapd_p,
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&hf_lapd_f,
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NULL,
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&hf_lapd_u_modifier_cmd,
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&hf_lapd_u_modifier_resp,
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NULL,
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&hf_lapd_ftype_s_u
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};
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/* Used only for I and S frames */
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static const xdlc_cf_items lapd_cf_items_ext = {
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&hf_lapd_n_r,
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&hf_lapd_n_s,
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&hf_lapd_p_ext,
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&hf_lapd_f_ext,
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&hf_lapd_s_ftype,
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NULL,
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NULL,
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&hf_lapd_ftype_i,
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&hf_lapd_ftype_s_u_ext
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};
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/* LAPD frame detection state */
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enum lapd_bitstream_states {OUT_OF_SYNC, FLAGS, DATA};
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typedef struct lapd_byte_state {
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enum lapd_bitstream_states state; /* frame detection state */
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char full_byte; /* part of a full byte */
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char bit_offset; /* number of bits already got in the full byte */
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int ones; /* number of consecutive ones since the last zero */
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} lapd_byte_state_t;
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typedef struct lapd_ppi {
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gboolean has_crc; /* CRC is captured with LAPD the frames */
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lapd_byte_state_t start_byte_state; /* LAPD bitstream byte state at the beginnigng of processing the packet */
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} lapd_ppi_t;
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/* Fill values in lapd_byte_state struct */
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static void
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fill_lapd_byte_state(lapd_byte_state_t *ptr, enum lapd_bitstream_states state, char full_byte, char bit_offset, int ones)
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{
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ptr->state = state;
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ptr->full_byte = full_byte;
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ptr->bit_offset = bit_offset;
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ptr->ones = ones;
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}
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typedef struct lapd_convo_data {
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address addr_a;
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address addr_b;
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guint32 port_a;
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guint32 port_b;
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lapd_byte_state_t *byte_state_a;
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lapd_byte_state_t *byte_state_b;
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} lapd_convo_data_t;
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#define MAX_LAPD_PACKET_LEN 1024
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static void
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dissect_lapd(tvbuff_t*, packet_info*, proto_tree*);
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/* got new LAPD frame byte */
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static void new_byte(char full_byte, char data[], int *data_len) {
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if (*data_len < MAX_LAPD_PACKET_LEN) {
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data[*data_len] = full_byte;
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(*data_len)++;
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} else {
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/* XXX : we are not prepared for that big messages, drop the last byte */
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}
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}
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static void
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dissect_lapd_bitstream(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
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{
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guint8 byte, full_byte = 0x00, bit_offset = 0;
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gboolean bit;
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guint8 i, ones = 0, data[MAX_LAPD_PACKET_LEN];
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int data_len = 0;
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gint offset = 0, available;
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guint8 *buff;
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tvbuff_t *new_tvb;
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enum lapd_bitstream_states state = OUT_OF_SYNC;
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lapd_ppi_t *lapd_ppi;
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conversation_t *conversation = NULL;
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lapd_convo_data_t *convo_data = NULL;
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lapd_byte_state_t *lapd_byte_state, *prev_byte_state = NULL;
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gboolean forward_stream = TRUE;
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/* get remaining data from previous packets */
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conversation = find_conversation(pinfo->fd->num, &pinfo->src, &pinfo->dst,
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pinfo->ptype, pinfo->srcport, pinfo->destport, 0);
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lapd_ppi = (lapd_ppi_t*)p_get_proto_data(pinfo->fd, proto_lapd);
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if (lapd_ppi) {
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prev_byte_state = &lapd_ppi->start_byte_state;
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if (prev_byte_state) {
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state = prev_byte_state->state;
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full_byte = prev_byte_state->full_byte;
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bit_offset = prev_byte_state->bit_offset;
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ones = prev_byte_state->ones;
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}
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} else if (conversation) {
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convo_data = (lapd_convo_data_t*)conversation_get_proto_data(conversation, proto_lapd);
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if (NULL != convo_data) {
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if (ADDRESSES_EQUAL(&convo_data->addr_a, &pinfo->src)
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&& ADDRESSES_EQUAL(&convo_data->addr_b, &pinfo->dst)
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&& convo_data-> port_a == pinfo->srcport
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&& convo_data-> port_b == pinfo->destport) {
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/* "forward" direction */
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forward_stream = TRUE;
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prev_byte_state = convo_data->byte_state_a;
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} else if (ADDRESSES_EQUAL(&convo_data-> addr_b, &pinfo->src)
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&& ADDRESSES_EQUAL(&convo_data->addr_a, &pinfo->dst)
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&& convo_data-> port_b == pinfo->srcport
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&& convo_data-> port_a == pinfo->destport) {
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/* "backward" direction */
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forward_stream = FALSE;
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prev_byte_state = convo_data->byte_state_b;
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}
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}
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if (prev_byte_state) {
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state = prev_byte_state->state;
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full_byte = prev_byte_state->full_byte;
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bit_offset = prev_byte_state->bit_offset;
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ones = prev_byte_state->ones;
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}
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}
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/* Consume tvb bytes */
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available = tvb_length_remaining(tvb, offset);
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while (offset < available) {
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byte = tvb_get_guint8(tvb,offset);
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offset++;
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for (i=0; i < 8; i++) { /* cycle through bits */
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bit = byte & (0x80 >> i) ? TRUE : FALSE;
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/* consume a bit */
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if (bit) {
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ones++;
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full_byte |= (1 << bit_offset++);
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} else {
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if (ones == 5 && state == DATA) {
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/* we don't increase bit_offset, it is an inserted zero */
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} else if (ones == 6 && state == DATA) { /* probably starting flag sequence */
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buff = g_memdup(data, data_len);
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/* Allocate new tvb for the LAPD frame */
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new_tvb = tvb_new_child_real_data(tvb, buff, data_len, data_len);
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tvb_set_free_cb(new_tvb, g_free);
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add_new_data_source(pinfo, new_tvb, "Decoded LAPD bitstream");
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dissect_lapd(new_tvb, pinfo, tree);
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data_len = 0;
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state = FLAGS;
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bit_offset++;
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} else if (ones >= 7) { /* frame reset or 11111111 flag byte */
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data_len = 0;
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state = OUT_OF_SYNC;
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bit_offset++;
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} else {
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bit_offset++;
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}
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ones = 0;
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}
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if (bit_offset == 8) { /* we have a new complete byte */
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switch (state) {
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case OUT_OF_SYNC:
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if (full_byte == 0x7E) { /* we have a flag byte */
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state = FLAGS;
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full_byte = 0x00;
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bit_offset = 0;
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} else { /* no sync yet, wait for a new byte */
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full_byte = (full_byte >> 1) & 0x7F;
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bit_offset--;
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}
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break;
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case FLAGS:
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if (full_byte == 0x7E) { /* we have a flag byte */
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full_byte = 0x00;
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bit_offset = 0;
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} else { /* we got the first data byte */
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state = DATA;
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new_byte(full_byte, data, &data_len);
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full_byte = 0x00;
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bit_offset = 0;
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}
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break;
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case DATA:
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/* we got a new data byte */
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new_byte(full_byte, data, &data_len);
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full_byte = 0x00;
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bit_offset = 0;
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break;
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}
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}
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}
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}
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if (state == DATA) { /* we are in the middle of an LAPD frame, we need more bytes */
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pinfo->desegment_offset = 0;
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pinfo->desegment_len = DESEGMENT_ONE_MORE_SEGMENT;
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return;
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} else { /* finished processing LAPD frame(s) */
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if (NULL == p_get_proto_data(pinfo->fd, proto_lapd)) {
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/* Per packet information */
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lapd_ppi = se_alloc(sizeof(lapd_ppi_t));
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lapd_ppi->has_crc = TRUE;
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if (prev_byte_state)
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fill_lapd_byte_state(&lapd_ppi->start_byte_state, prev_byte_state->state,
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prev_byte_state->full_byte, prev_byte_state->bit_offset,
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prev_byte_state->ones);
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else
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fill_lapd_byte_state(&lapd_ppi->start_byte_state, OUT_OF_SYNC, 0x00, 0, 0);
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p_add_proto_data(pinfo->fd, proto_lapd, lapd_ppi);
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/* Conversation info*/
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if (conversation) {
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if (convo_data) { /* already have lapd convo data */
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if (forward_stream)
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fill_lapd_byte_state(convo_data->byte_state_a, state, full_byte, bit_offset, ones);
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else {
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if (!convo_data->byte_state_b)
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convo_data->byte_state_b = se_alloc(sizeof(lapd_byte_state_t));
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fill_lapd_byte_state(convo_data->byte_state_b, state, full_byte, bit_offset, ones);
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}
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} else { /* lapd convo data has to be created */
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lapd_byte_state = se_alloc(sizeof(lapd_byte_state_t));
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fill_lapd_byte_state(lapd_byte_state, state, full_byte, bit_offset, ones);
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convo_data = se_alloc(sizeof(lapd_convo_data_t));
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COPY_ADDRESS(&convo_data->addr_a, &pinfo->src);
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COPY_ADDRESS(&convo_data->addr_b, &pinfo->dst);
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convo_data->port_a = pinfo->srcport;
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convo_data->port_b = pinfo->destport;
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convo_data->byte_state_a = lapd_byte_state;
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convo_data->byte_state_b = NULL;
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conversation_add_proto_data(conversation, proto_lapd, convo_data);
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}
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}
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}
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}
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}
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static void
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dissect_lapd(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
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{
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proto_tree *lapd_tree, *addr_tree, *checksum_tree;
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proto_item *lapd_ti, *addr_ti, *checksum_ti;
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int direction;
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guint16 control, checksum, checksum_calculated;
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int lapd_header_len, checksum_offset;
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guint16 addr, cr, sapi, tei;
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gboolean is_response = 0;
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tvbuff_t *next_tvb;
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const char *srcname = "?";
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const char *dstname = "?";
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col_set_str(pinfo->cinfo, COL_PROTOCOL, "LAPD");
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col_clear(pinfo->cinfo, COL_INFO);
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addr = tvb_get_ntohs(tvb, 0);
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cr = addr & LAPD_CR;
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tei = (addr & LAPD_TEI) >> LAPD_TEI_SHIFT;
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sapi = (addr & LAPD_SAPI) >> LAPD_SAPI_SHIFT;
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lapd_header_len = 2; /* addr */
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if (check_col(pinfo->cinfo, COL_TEI))
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col_add_fstr(pinfo->cinfo, COL_TEI, "%u", tei);
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/* Append TEI to info field */
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col_append_fstr(pinfo->cinfo, COL_INFO, "TEI:%02u ", tei);
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col_set_fence(pinfo->cinfo, COL_INFO);
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if (pinfo->fd->lnk_t == WTAP_ENCAP_LINUX_LAPD) {
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/* frame is captured via libpcap */
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if (pinfo->pseudo_header->lapd.pkttype == 4 /*PACKET_OUTGOING*/) {
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if (pinfo->pseudo_header->lapd.we_network) {
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is_response = cr ? FALSE : TRUE;
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srcname = "Local Network";
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dstname = "Remote User";
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direction = P2P_DIR_RECV; /* Network->User */
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} else {
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srcname = "Local User";
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dstname = "Remote Network";
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direction = P2P_DIR_SENT; /* User->Network */
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}
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}
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else if (pinfo->pseudo_header->lapd.pkttype == 3 /*PACKET_OTHERHOST*/) {
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/* We must be a TE, sniffing what other TE transmit */
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is_response = cr ? TRUE : FALSE;
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srcname = "Remote User";
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dstname = "Remote Network";
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direction = P2P_DIR_SENT; /* User->Network */
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}
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else {
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/* The frame is incoming */
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if (pinfo->pseudo_header->lapd.we_network) {
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is_response = cr ? TRUE : FALSE;
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srcname = "Remote User";
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dstname = "Local Network";
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direction = P2P_DIR_SENT; /* User->Network */
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} else {
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is_response = cr ? FALSE : TRUE;
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srcname = "Remote Network";
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dstname = "Local User";
|
|
direction = P2P_DIR_RECV; /* Network->User */
|
|
}
|
|
}
|
|
} else {
|
|
direction = pinfo->p2p_dir;
|
|
if (pinfo->p2p_dir == P2P_DIR_RECV) {
|
|
is_response = cr ? FALSE : TRUE;
|
|
srcname = "Network";
|
|
dstname = "User";
|
|
}
|
|
else if (pinfo->p2p_dir == P2P_DIR_SENT) {
|
|
is_response = cr ? TRUE : FALSE;
|
|
srcname = "User";
|
|
dstname = "Network";
|
|
}
|
|
}
|
|
|
|
col_set_str(pinfo->cinfo, COL_RES_DL_SRC, srcname);
|
|
col_set_str(pinfo->cinfo, COL_RES_DL_DST, dstname);
|
|
|
|
if (tree) {
|
|
proto_item *direction_ti;
|
|
|
|
lapd_ti = proto_tree_add_item(tree, proto_lapd, tvb, 0, -1,
|
|
ENC_NA);
|
|
lapd_tree = proto_item_add_subtree(lapd_ti, ett_lapd);
|
|
|
|
/*
|
|
* Don't show the direction if we don't know it.
|
|
*/
|
|
if (direction != P2P_DIR_UNKNOWN) {
|
|
direction_ti = proto_tree_add_uint(lapd_tree, hf_lapd_direction,
|
|
tvb, 0, 0, pinfo->p2p_dir);
|
|
PROTO_ITEM_SET_GENERATED(direction_ti);
|
|
}
|
|
|
|
addr_ti = proto_tree_add_uint(lapd_tree, hf_lapd_address, tvb,
|
|
0, 2, addr);
|
|
addr_tree = proto_item_add_subtree(addr_ti, ett_lapd_address);
|
|
|
|
if(global_lapd_gsm_sapis){
|
|
proto_tree_add_uint(addr_tree, hf_lapd_gsm_sapi,tvb, 0, 1, addr);
|
|
}else{
|
|
proto_tree_add_uint(addr_tree, hf_lapd_sapi,tvb, 0, 1, addr);
|
|
}
|
|
proto_tree_add_uint(addr_tree, hf_lapd_cr, tvb, 0, 1, addr);
|
|
proto_tree_add_uint(addr_tree, hf_lapd_ea1, tvb, 0, 1, addr);
|
|
proto_tree_add_uint(addr_tree, hf_lapd_tei, tvb, 1, 1, addr);
|
|
proto_tree_add_uint(addr_tree, hf_lapd_ea2, tvb, 1, 1, addr);
|
|
}
|
|
else {
|
|
lapd_ti = NULL;
|
|
lapd_tree = NULL;
|
|
}
|
|
|
|
control = dissect_xdlc_control(tvb, 2, pinfo, lapd_tree, hf_lapd_control,
|
|
ett_lapd_control, &lapd_cf_items, &lapd_cf_items_ext, NULL, NULL,
|
|
is_response, TRUE, FALSE);
|
|
lapd_header_len += XDLC_CONTROL_LEN(control, TRUE);
|
|
|
|
if (tree)
|
|
proto_item_set_len(lapd_ti, lapd_header_len);
|
|
|
|
if (NULL != p_get_proto_data(pinfo->fd, proto_lapd)
|
|
&& ((lapd_ppi_t*)p_get_proto_data(pinfo->fd, proto_lapd))->has_crc) {
|
|
|
|
/* check checksum */
|
|
checksum_offset = tvb_length(tvb) - 2;
|
|
checksum = tvb_get_guint8(tvb, checksum_offset); /* high byte */
|
|
checksum <<= 8;
|
|
checksum |= tvb_get_guint8(tvb, checksum_offset+1) & 0x00FF; /* low byte */
|
|
checksum_calculated = crc16_ccitt_tvb(tvb, tvb_length(tvb) - 2);
|
|
checksum_calculated = g_htons(checksum_calculated); /* Note: g_htons() macro may eval arg multiple times */
|
|
|
|
if (checksum == checksum_calculated) {
|
|
checksum_ti = proto_tree_add_uint_format(lapd_tree, hf_lapd_checksum, tvb, checksum_offset, 2, 0,"Checksum: 0x%04x [correct]", checksum);
|
|
checksum_tree = proto_item_add_subtree(checksum_ti, ett_lapd_checksum);
|
|
proto_tree_add_boolean(checksum_tree, hf_lapd_checksum_good, tvb, checksum_offset, 2, TRUE);
|
|
proto_tree_add_boolean(checksum_tree, hf_lapd_checksum_bad, tvb, checksum_offset, 2, FALSE);
|
|
} else {
|
|
checksum_ti = proto_tree_add_uint_format(lapd_tree, hf_lapd_checksum, tvb, checksum_offset, 2, 0,"Checksum: 0x%04x [incorrect, should be 0x%04x]", checksum, checksum_calculated);
|
|
checksum_tree = proto_item_add_subtree(checksum_ti, ett_lapd_checksum);
|
|
proto_tree_add_boolean(checksum_tree, hf_lapd_checksum_good, tvb, checksum_offset, 2, FALSE);
|
|
proto_tree_add_boolean(checksum_tree, hf_lapd_checksum_bad, tvb, checksum_offset, 2, TRUE);
|
|
}
|
|
|
|
next_tvb = tvb_new_subset(tvb, lapd_header_len, tvb_length_remaining(tvb,lapd_header_len) - 2, -1);
|
|
|
|
} else
|
|
next_tvb = tvb_new_subset_remaining(tvb, lapd_header_len);
|
|
|
|
/* Dissection done, append " | " to COL_INFO */
|
|
col_append_fstr(pinfo->cinfo, COL_INFO, " | ");
|
|
col_set_fence(pinfo->cinfo, COL_INFO);
|
|
|
|
if (XDLC_IS_INFORMATION(control)) {
|
|
/* call next protocol */
|
|
if(global_lapd_gsm_sapis){
|
|
if (!dissector_try_uint(lapd_gsm_sapi_dissector_table, sapi,
|
|
next_tvb, pinfo, tree))
|
|
call_dissector(data_handle,next_tvb, pinfo, tree);
|
|
}else{
|
|
if (!dissector_try_uint(lapd_sapi_dissector_table, sapi,
|
|
next_tvb, pinfo, tree))
|
|
call_dissector(data_handle,next_tvb, pinfo, tree);
|
|
}
|
|
} else
|
|
call_dissector(data_handle,next_tvb, pinfo, tree);
|
|
}
|
|
|
|
void
|
|
proto_reg_handoff_lapd(void);
|
|
|
|
void
|
|
proto_register_lapd(void)
|
|
{
|
|
static hf_register_info hf[] = {
|
|
|
|
{ &hf_lapd_direction,
|
|
{ "Direction", "lapd.direction", FT_UINT8, BASE_DEC, VALS(lapd_direction_vals), 0x0,
|
|
NULL, HFILL }},
|
|
|
|
{ &hf_lapd_address,
|
|
{ "Address Field", "lapd.address", FT_UINT16, BASE_HEX, NULL, 0x0,
|
|
"Address", HFILL }},
|
|
|
|
{ &hf_lapd_sapi,
|
|
{ "SAPI", "lapd.sapi", FT_UINT16, BASE_DEC, VALS(lapd_sapi_vals), LAPD_SAPI,
|
|
"Service Access Point Identifier", HFILL }},
|
|
|
|
{ &hf_lapd_gsm_sapi,
|
|
{ "SAPI", "lapd.sapi", FT_UINT16, BASE_DEC, VALS(lapd_gsm_sapi_vals), LAPD_SAPI,
|
|
"Service Access Point Identifier", HFILL }},
|
|
|
|
{ &hf_lapd_cr,
|
|
{ "C/R", "lapd.cr", FT_UINT16, BASE_DEC, NULL, LAPD_CR,
|
|
"Command/Response bit", HFILL }},
|
|
|
|
{ &hf_lapd_ea1,
|
|
{ "EA1", "lapd.ea1", FT_UINT16, BASE_DEC, NULL, LAPD_EA1,
|
|
"First Address Extension bit", HFILL }},
|
|
|
|
{ &hf_lapd_tei,
|
|
{ "TEI", "lapd.tei", FT_UINT16, BASE_DEC, NULL, LAPD_TEI,
|
|
"Terminal Endpoint Identifier", HFILL }},
|
|
|
|
{ &hf_lapd_ea2,
|
|
{ "EA2", "lapd.ea2", FT_UINT16, BASE_DEC, NULL, LAPD_EA2,
|
|
"Second Address Extension bit", HFILL }},
|
|
|
|
{ &hf_lapd_control,
|
|
{ "Control Field", "lapd.control", FT_UINT16, BASE_HEX, NULL, 0x0,
|
|
NULL, HFILL }},
|
|
|
|
{ &hf_lapd_n_r,
|
|
{ "N(R)", "lapd.control.n_r", FT_UINT16, BASE_DEC,
|
|
NULL, XDLC_N_R_EXT_MASK, NULL, HFILL }},
|
|
|
|
{ &hf_lapd_n_s,
|
|
{ "N(S)", "lapd.control.n_s", FT_UINT16, BASE_DEC,
|
|
NULL, XDLC_N_S_EXT_MASK, NULL, HFILL }},
|
|
|
|
{ &hf_lapd_p,
|
|
{ "Poll", "lapd.control.p", FT_BOOLEAN, 8,
|
|
TFS(&tfs_set_notset), XDLC_P_F, NULL, HFILL }},
|
|
|
|
{ &hf_lapd_p_ext,
|
|
{ "Poll", "lapd.control.p", FT_BOOLEAN, 16,
|
|
TFS(&tfs_set_notset), XDLC_P_F_EXT, NULL, HFILL }},
|
|
|
|
{ &hf_lapd_f,
|
|
{ "Final", "lapd.control.f", FT_BOOLEAN, 8,
|
|
TFS(&tfs_set_notset), XDLC_P_F, NULL, HFILL }},
|
|
|
|
{ &hf_lapd_f_ext,
|
|
{ "Final", "lapd.control.f", FT_BOOLEAN, 16,
|
|
TFS(&tfs_set_notset), XDLC_P_F_EXT, NULL, HFILL }},
|
|
|
|
{ &hf_lapd_s_ftype,
|
|
{ "Supervisory frame type", "lapd.control.s_ftype", FT_UINT16, BASE_HEX,
|
|
VALS(stype_vals), XDLC_S_FTYPE_MASK, NULL, HFILL }},
|
|
|
|
{ &hf_lapd_u_modifier_cmd,
|
|
{ "Command", "lapd.control.u_modifier_cmd", FT_UINT8, BASE_HEX,
|
|
VALS(modifier_vals_cmd), XDLC_U_MODIFIER_MASK, NULL, HFILL }},
|
|
|
|
{ &hf_lapd_u_modifier_resp,
|
|
{ "Response", "lapd.control.u_modifier_resp", FT_UINT8, BASE_HEX,
|
|
VALS(modifier_vals_resp), XDLC_U_MODIFIER_MASK, NULL, HFILL }},
|
|
|
|
{ &hf_lapd_ftype_i,
|
|
{ "Frame type", "lapd.control.ftype", FT_UINT16, BASE_HEX,
|
|
VALS(ftype_vals), XDLC_I_MASK, NULL, HFILL }},
|
|
|
|
{ &hf_lapd_ftype_s_u,
|
|
{ "Frame type", "lapd.control.ftype", FT_UINT8, BASE_HEX,
|
|
VALS(ftype_vals), XDLC_S_U_MASK, NULL, HFILL }},
|
|
|
|
{ &hf_lapd_ftype_s_u_ext,
|
|
{ "Frame type", "lapd.control.ftype", FT_UINT16, BASE_HEX,
|
|
VALS(ftype_vals), XDLC_S_U_MASK, NULL, HFILL }},
|
|
|
|
{ &hf_lapd_checksum,
|
|
{ "Checksum", "lapd.checksum", FT_UINT16, BASE_HEX,
|
|
NULL, 0x0, "Details at: http://www.wireshark.org/docs/wsug_html_chunked/ChAdvChecksums.html", HFILL }},
|
|
|
|
{ &hf_lapd_checksum_good,
|
|
{ "Good Checksum", "lapd.checksum_good", FT_BOOLEAN, BASE_NONE,
|
|
NULL, 0x0, "True: checksum matches packet content; False: doesn't match content or not checked", HFILL }},
|
|
|
|
{ &hf_lapd_checksum_bad,
|
|
{ "Bad Checksum", "lapd.checksum_bad", FT_BOOLEAN, BASE_NONE,
|
|
NULL, 0x0, "True: checksum doesn't match packet content; False: matches content or not checked", HFILL }}
|
|
};
|
|
|
|
static gint *ett[] = {
|
|
&ett_lapd,
|
|
&ett_lapd_address,
|
|
&ett_lapd_control,
|
|
&ett_lapd_checksum
|
|
};
|
|
|
|
module_t *lapd_module;
|
|
|
|
proto_lapd = proto_register_protocol("Link Access Procedure, Channel D (LAPD)",
|
|
"LAPD", "lapd");
|
|
proto_register_field_array (proto_lapd, hf, array_length(hf));
|
|
proto_register_subtree_array(ett, array_length(ett));
|
|
|
|
register_dissector("lapd", dissect_lapd, proto_lapd);
|
|
|
|
lapd_sapi_dissector_table = register_dissector_table("lapd.sapi",
|
|
"LAPD SAPI", FT_UINT16, BASE_DEC);
|
|
|
|
lapd_gsm_sapi_dissector_table = register_dissector_table("lapd.gsm.sapi",
|
|
"LAPD GSM SAPI", FT_UINT16, BASE_DEC);
|
|
|
|
lapd_module = prefs_register_protocol(proto_lapd, proto_reg_handoff_lapd);
|
|
|
|
prefs_register_bool_preference(lapd_module, "use_gsm_sapi_values",
|
|
"Use GSM SAPI values",
|
|
"Use SAPI values as specified in TS 48 056",
|
|
&global_lapd_gsm_sapis);
|
|
prefs_register_uint_preference(lapd_module, "rtp_payload_type",
|
|
"RTP payload type for embedded LAPD",
|
|
"RTP payload type for embedded LAPD. It must be one of the dynamic types "
|
|
"from 96 to 127. Set it to 0 to disable.",
|
|
10, &pref_lapd_rtp_payload_type);
|
|
|
|
}
|
|
|
|
void
|
|
proto_reg_handoff_lapd(void)
|
|
{
|
|
static gboolean init = FALSE;
|
|
static dissector_handle_t lapd_bitstream_handle;
|
|
static gint lapd_rtp_payload_type;
|
|
|
|
if (!init) {
|
|
dissector_handle_t lapd_handle;
|
|
|
|
lapd_handle = find_dissector("lapd");
|
|
dissector_add_uint("wtap_encap", WTAP_ENCAP_LINUX_LAPD, lapd_handle);
|
|
dissector_add_uint("wtap_encap", WTAP_ENCAP_LAPD, lapd_handle);
|
|
|
|
lapd_bitstream_handle = create_dissector_handle(dissect_lapd_bitstream, proto_lapd);
|
|
data_handle = find_dissector("data");
|
|
|
|
init = TRUE;
|
|
} else {
|
|
if ((lapd_rtp_payload_type > 95) && (lapd_rtp_payload_type < 128))
|
|
dissector_delete_uint("rtp.pt", lapd_rtp_payload_type, lapd_bitstream_handle);
|
|
}
|
|
|
|
lapd_rtp_payload_type = pref_lapd_rtp_payload_type;
|
|
if ((lapd_rtp_payload_type > 95) && (lapd_rtp_payload_type < 128))
|
|
dissector_add_uint("rtp.pt", lapd_rtp_payload_type, lapd_bitstream_handle);
|
|
}
|