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wireshark/epan/dissectors/packet-lapd.c

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/* packet-lapd.c
* Routines for LAPD frame disassembly
* Gilbert Ramirez <gram@alumni.rice.edu>
*
* Wireshark - Network traffic analyzer
* By Gerald Combs <gerald@wireshark.org>
* Copyright 1998
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
/*
* LAPD bitstream over RTP handling
* Copyright 2008, Ericsson AB
* Written by Balint Reczey <balint.reczey@ericsson.com>
*
* ISDN/LAPD references:
*
* http://www.cisco.com/univercd/cc/td/doc/cisintwk/ito_doc/isdn.htm
* http://www.ece.wpi.edu/courses/ee535/hwk11cd95/agrebe/agrebe.html
* http://www.acacia-net.com/Clarinet/Protocol/q9213o84.htm
* http://www.itu.int/rec/T-REC-Q.921/en
* Base Station Controller - Base Transceiver Station (BSC - BTS) interface; Layer 2 specification
* http://www.3gpp.org/ftp/Specs/html-info/48056.htm
*/
#include "config.h"
#include <epan/packet.h>
#include <epan/conversation.h>
#include <epan/xdlc.h>
#include <epan/crc16-tvb.h>
#include <epan/prefs.h>
#include <wiretap/wtap.h>
#include <epan/lapd_sapi.h>
#include <epan/expert.h>
#include "packet-l2tp.h"
void proto_register_lapd(void);
void proto_reg_handoff_lapd(void);
static int proto_lapd = -1;
static int hf_lapd_direction = -1;
static int hf_lapd_address = -1;
static int hf_lapd_sapi = -1;
static int hf_lapd_gsm_sapi = -1;
static int hf_lapd_cr = -1;
static int hf_lapd_ea1 = -1;
static int hf_lapd_tei = -1;
static int hf_lapd_ea2 = -1;
static int hf_lapd_control = -1;
static int hf_lapd_n_r = -1;
static int hf_lapd_n_s = -1;
static int hf_lapd_p = -1;
static int hf_lapd_p_ext = -1;
static int hf_lapd_f = -1;
static int hf_lapd_f_ext = -1;
static int hf_lapd_s_ftype = -1;
static int hf_lapd_u_modifier_cmd = -1;
static int hf_lapd_u_modifier_resp = -1;
static int hf_lapd_ftype_i = -1;
static int hf_lapd_ftype_s_u = -1;
static int hf_lapd_ftype_s_u_ext = -1;
static int hf_lapd_checksum = -1;
static int hf_lapd_checksum_good = -1;
static int hf_lapd_checksum_bad = -1;
static gint ett_lapd = -1;
static gint ett_lapd_address = -1;
static gint ett_lapd_control = -1;
static gint ett_lapd_checksum = -1;
static gint pref_lapd_rtp_payload_type = 0;
static expert_field ei_lapd_abort = EI_INIT;
static expert_field ei_lapd_checksum_bad = EI_INIT;
static dissector_table_t lapd_sapi_dissector_table;
static dissector_table_t lapd_gsm_sapi_dissector_table;
/* Whether to use GSM SAPI vals or not */
static gboolean global_lapd_gsm_sapis = FALSE;
static dissector_handle_t data_handle;
/*
* Bits in the address field.
*/
#define LAPD_SAPI 0xfc00 /* Service Access Point Identifier */
#define LAPD_SAPI_SHIFT 10
#define LAPD_CR 0x0200 /* Command/Response bit */
#define LAPD_EA1 0x0100 /* First Address Extension bit */
#define LAPD_TEI 0x00fe /* Terminal Endpoint Identifier */
#define LAPD_TEI_SHIFT 1
#define LAPD_EA2 0x0001 /* Second Address Extension bit */
static const value_string lapd_direction_vals[] = {
{ P2P_DIR_RECV, "Network->User"},
{ P2P_DIR_SENT, "User->Network"},
{ 0, NULL }
};
static const value_string lapd_sapi_vals[] = {
{ LAPD_SAPI_Q931, "Q.931 Call control procedure" },
{ LAPD_SAPI_PM_Q931, "Packet mode Q.931 Call control procedure" },
{ LAPD_SAPI_X25, "X.25 Level 3 procedures" },
{ LAPD_SAPI_L2, "Layer 2 management procedures" },
{ 0, NULL }
};
static const value_string lapd_gsm_sapi_vals[] = {
{ LAPD_GSM_SAPI_RA_SIG_PROC, "Radio signalling procedures" },
{ LAPD_GSM_SAPI_NOT_USED_1, "(Not used in GSM PLMN)" },
{ LAPD_GSM_SAPI_NOT_USED_16, "(Not used in GSM PLMN)" },
{ LAPD_GSM_SAPI_OM_PROC, "Operation and maintenance procedure" },
{ LAPD_SAPI_L2, "Layer 2 management procedures" },
{ 0, NULL }
};
/* Used only for U frames */
static const xdlc_cf_items lapd_cf_items = {
NULL,
NULL,
&hf_lapd_p,
&hf_lapd_f,
NULL,
&hf_lapd_u_modifier_cmd,
&hf_lapd_u_modifier_resp,
NULL,
&hf_lapd_ftype_s_u
};
/* Used only for I and S frames */
static const xdlc_cf_items lapd_cf_items_ext = {
&hf_lapd_n_r,
&hf_lapd_n_s,
&hf_lapd_p_ext,
&hf_lapd_f_ext,
&hf_lapd_s_ftype,
NULL,
NULL,
&hf_lapd_ftype_i,
&hf_lapd_ftype_s_u_ext
};
#define MAX_LAPD_PACKET_LEN 1024
/* LAPD frame detection state */
enum lapd_bitstream_states {OUT_OF_SYNC, FLAGS, DATA};
typedef struct lapd_byte_state {
enum lapd_bitstream_states state; /* frame detection state */
char full_byte; /* part of a full byte */
char bit_offset; /* number of bits already got in the full byte */
int ones; /* number of consecutive ones since the last zero */
char data[MAX_LAPD_PACKET_LEN];
int data_len;
} lapd_byte_state_t;
typedef struct lapd_ppi {
gboolean has_crc; /* CRC is captured with LAPD the frames */
lapd_byte_state_t start_byte_state; /* LAPD bitstream byte state at the beginning of processing the packet */
} lapd_ppi_t;
/* Fill values in lapd_byte_state struct */
static void
fill_lapd_byte_state(lapd_byte_state_t *ptr, enum lapd_bitstream_states state, char full_byte, char bit_offset, int ones, char *data, int data_len)
{
ptr->state = state;
ptr->full_byte = full_byte;
ptr->bit_offset = bit_offset;
ptr->ones = ones;
ptr->data_len = MIN((int)sizeof(ptr->data), data_len);
memcpy(ptr->data, data, ptr->data_len);
}
typedef struct lapd_convo_data {
address addr_a;
address addr_b;
guint32 port_a;
guint32 port_b;
lapd_byte_state_t *byte_state_a;
lapd_byte_state_t *byte_state_b;
} lapd_convo_data_t;
static void
dissect_lapd_full(tvbuff_t*, packet_info*, proto_tree*, gboolean);
/* got new LAPD frame byte */
static void new_byte(char full_byte, char data[], int *data_len) {
if (*data_len < MAX_LAPD_PACKET_LEN) {
data[*data_len] = full_byte;
(*data_len)++;
} else {
/* XXX : we are not prepared for that big messages, drop the last byte */
}
}
static void
lapd_log_abort(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, guint offset, const char *msg)
{
proto_item *ti;
ti = proto_tree_add_item(tree, proto_lapd, tvb, offset, 1, ENC_NA);
expert_add_info_format(pinfo, ti, &ei_lapd_abort, "%s", msg);
}
static int
dissect_lapd_bitstream(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void* dissector_data _U_)
{
guint8 byte, full_byte = 0x00, bit_offset = 0;
gboolean bit;
guint8 i, ones = 0, data[MAX_LAPD_PACKET_LEN];
int data_len = 0;
gint offset = 0, available;
guint8 *buff;
tvbuff_t *new_tvb;
enum lapd_bitstream_states state = OUT_OF_SYNC;
lapd_ppi_t *lapd_ppi;
conversation_t *conversation = NULL;
lapd_convo_data_t *convo_data = NULL;
lapd_byte_state_t *lapd_byte_state, *prev_byte_state = NULL;
gboolean forward_stream = TRUE;
/* get remaining data from previous packets */
conversation = find_or_create_conversation(pinfo);
lapd_ppi = (lapd_ppi_t*)p_get_proto_data(wmem_file_scope(), pinfo, proto_lapd, 0);
if (lapd_ppi) {
prev_byte_state = &lapd_ppi->start_byte_state;
if (prev_byte_state) {
state = prev_byte_state->state;
full_byte = prev_byte_state->full_byte;
bit_offset = prev_byte_state->bit_offset;
ones = prev_byte_state->ones;
memcpy(data, prev_byte_state->data, prev_byte_state->data_len);
data_len = prev_byte_state->data_len;
}
} else if (conversation) {
convo_data = (lapd_convo_data_t*)conversation_get_proto_data(conversation, proto_lapd);
if (NULL != convo_data) {
if (addresses_equal(&convo_data->addr_a, &pinfo->src)
&& addresses_equal(&convo_data->addr_b, &pinfo->dst)
&& convo_data-> port_a == pinfo->srcport
&& convo_data-> port_b == pinfo->destport) {
/* "forward" direction */
forward_stream = TRUE;
prev_byte_state = convo_data->byte_state_a;
} else if (addresses_equal(&convo_data-> addr_b, &pinfo->src)
&& addresses_equal(&convo_data->addr_a, &pinfo->dst)
&& convo_data-> port_b == pinfo->srcport
&& convo_data-> port_a == pinfo->destport) {
/* "backward" direction */
forward_stream = FALSE;
prev_byte_state = convo_data->byte_state_b;
}
}
if (prev_byte_state) {
state = prev_byte_state->state;
full_byte = prev_byte_state->full_byte;
bit_offset = prev_byte_state->bit_offset;
ones = prev_byte_state->ones;
memcpy(data, prev_byte_state->data, prev_byte_state->data_len);
data_len = prev_byte_state->data_len;
}
}
/* Consume tvb bytes */
available = tvb_reported_length_remaining(tvb, offset);
while (offset < available) {
byte = tvb_get_guint8(tvb,offset);
offset++;
for (i=0; i < 8; i++) { /* cycle through bits */
bit = byte & (0x80 >> i) ? TRUE : FALSE;
/* consume a bit */
if (bit) {
ones++;
full_byte |= (1 << bit_offset++);
} else {
if (ones == 5 && state == DATA) {
/* we don't increase bit_offset, it is an inserted zero */
} else if (ones == 6 && state == DATA) { /* probably starting flag sequence */
buff = (guint8 *)g_memdup(data, data_len);
/* Allocate new tvb for the LAPD frame */
new_tvb = tvb_new_child_real_data(tvb, buff, data_len, data_len);
tvb_set_free_cb(new_tvb, g_free);
add_new_data_source(pinfo, new_tvb, "Decoded LAPD bitstream");
data_len = 0;
state = FLAGS;
bit_offset++;
if (full_byte != 0x7E) {
data_len = 0;
state = OUT_OF_SYNC;
lapd_log_abort(tvb, pinfo, tree, offset, "Abort! 6 ones that don't match 0x7e!");
}
dissect_lapd_full(new_tvb, pinfo, tree, TRUE);
} else if (ones >= 7) { /* frame reset or 11111111 flag byte */
data_len = 0;
state = OUT_OF_SYNC;
bit_offset++;
lapd_log_abort(tvb, pinfo, tree, offset, "Abort! 7 ones!");
} else {
bit_offset++;
}
ones = 0;
}
if (bit_offset == 8) { /* we have a new complete byte */
switch (state) {
case OUT_OF_SYNC:
if (full_byte == 0x7E) { /* we have a flag byte */
state = FLAGS;
full_byte = 0x00;
bit_offset = 0;
} else { /* no sync yet, wait for a new byte */
full_byte = (full_byte >> 1) & 0x7F;
bit_offset--;
}
break;
case FLAGS:
if (full_byte == 0x7E) { /* we have a flag byte */
full_byte = 0x00;
bit_offset = 0;
} else { /* we got the first data byte */
state = DATA;
new_byte(full_byte, data, &data_len);
full_byte = 0x00;
bit_offset = 0;
}
break;
case DATA:
/* we got a new data byte */
new_byte(full_byte, data, &data_len);
full_byte = 0x00;
bit_offset = 0;
break;
}
}
}
}
{
if (NULL == p_get_proto_data(wmem_file_scope(), pinfo, proto_lapd, 0)) {
/* Per packet information */
lapd_ppi = wmem_new(wmem_file_scope(), lapd_ppi_t);
lapd_ppi->has_crc = TRUE;
if (prev_byte_state)
fill_lapd_byte_state(&lapd_ppi->start_byte_state, prev_byte_state->state,
prev_byte_state->full_byte, prev_byte_state->bit_offset,
prev_byte_state->ones, prev_byte_state->data, prev_byte_state->data_len);
else
fill_lapd_byte_state(&lapd_ppi->start_byte_state, OUT_OF_SYNC, 0x00, 0, 0, data, 0);
p_add_proto_data(wmem_file_scope(), pinfo, proto_lapd, 0, lapd_ppi);
/* Conversation info*/
if (conversation) {
if (convo_data) { /* already have lapd convo data */
if (forward_stream)
fill_lapd_byte_state(convo_data->byte_state_a, state, full_byte, bit_offset, ones, data, data_len);
else {
if (!convo_data->byte_state_b)
convo_data->byte_state_b = wmem_new(wmem_file_scope(), lapd_byte_state_t);
fill_lapd_byte_state(convo_data->byte_state_b, state, full_byte, bit_offset, ones, data, data_len);
}
} else { /* lapd convo data has to be created */
lapd_byte_state = wmem_new(wmem_file_scope(), lapd_byte_state_t);
fill_lapd_byte_state(lapd_byte_state, state, full_byte, bit_offset, ones, data, data_len);
convo_data = wmem_new(wmem_file_scope(), lapd_convo_data_t);
copy_address(&convo_data->addr_a, &pinfo->src);
copy_address(&convo_data->addr_b, &pinfo->dst);
convo_data->port_a = pinfo->srcport;
convo_data->port_b = pinfo->destport;
convo_data->byte_state_a = lapd_byte_state;
convo_data->byte_state_b = NULL;
conversation_add_proto_data(conversation, proto_lapd, convo_data);
}
}
}
}
return tvb_captured_length(tvb);
}
static int
dissect_lapd(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void* data _U_)
{
dissect_lapd_full(tvb, pinfo, tree, FALSE);
return tvb_captured_length(tvb);
}
static void
dissect_lapd_full(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, gboolean has_crc)
{
proto_tree *lapd_tree, *addr_tree, *checksum_tree;
proto_item *lapd_ti, *addr_ti, *checksum_ti;
int direction;
guint16 control, checksum, checksum_calculated;
int lapd_header_len, checksum_offset;
guint16 addr, cr, sapi, tei;
gboolean is_response = 0;
tvbuff_t *next_tvb;
const char *srcname = "?";
const char *dstname = "?";
col_set_str(pinfo->cinfo, COL_PROTOCOL, "LAPD");
col_clear(pinfo->cinfo, COL_INFO);
addr = tvb_get_ntohs(tvb, 0);
cr = addr & LAPD_CR;
tei = (addr & LAPD_TEI) >> LAPD_TEI_SHIFT;
sapi = (addr & LAPD_SAPI) >> LAPD_SAPI_SHIFT;
lapd_header_len = 2; /* addr */
col_add_fstr(pinfo->cinfo, COL_TEI, "%u", tei);
/* Append TEI to info field */
col_append_fstr(pinfo->cinfo, COL_INFO, "TEI:%02u ", tei);
col_set_fence(pinfo->cinfo, COL_INFO);
if (pinfo->fd->lnk_t == WTAP_ENCAP_LINUX_LAPD) {
/* frame is captured via libpcap */
if (pinfo->pseudo_header->lapd.pkttype == 4 /*PACKET_OUTGOING*/) {
if (pinfo->pseudo_header->lapd.we_network) {
is_response = cr ? FALSE : TRUE;
srcname = "Local Network";
dstname = "Remote User";
direction = P2P_DIR_RECV; /* Network->User */
} else {
srcname = "Local User";
dstname = "Remote Network";
direction = P2P_DIR_SENT; /* User->Network */
}
}
else if (pinfo->pseudo_header->lapd.pkttype == 3 /*PACKET_OTHERHOST*/) {
/* We must be a TE, sniffing what other TE transmit */
is_response = cr ? TRUE : FALSE;
srcname = "Remote User";
dstname = "Remote Network";
direction = P2P_DIR_SENT; /* User->Network */
}
else {
/* The frame is incoming */
if (pinfo->pseudo_header->lapd.we_network) {
is_response = cr ? TRUE : FALSE;
srcname = "Remote User";
dstname = "Local Network";
direction = P2P_DIR_SENT; /* User->Network */
} else {
is_response = cr ? FALSE : TRUE;
srcname = "Remote Network";
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 (has_crc) {
/* check checksum */
checksum_offset = tvb_reported_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_reported_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_value(lapd_tree, hf_lapd_checksum, tvb, checksum_offset, 2, 0,"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 {
proto_item *pi;
checksum_ti = proto_tree_add_uint_format_value(lapd_tree, hf_lapd_checksum, tvb, checksum_offset, 2, 0,"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);
pi = proto_tree_add_boolean(checksum_tree, hf_lapd_checksum_bad, tvb, checksum_offset, 2, TRUE);
expert_add_info(pinfo, pi, &ei_lapd_checksum_bad);
}
next_tvb = tvb_new_subset_length(tvb, lapd_header_len, tvb_reported_length_remaining(tvb,lapd_header_len) - 2);
} else
next_tvb = tvb_new_subset_remaining(tvb, lapd_header_len);
/* Dissection done, append " | " to COL_INFO */
col_append_str(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);
}
static gboolean
dissect_udp_lapd(tvbuff_t *tvb, packet_info *pinfo _U_ , proto_tree *tree, void *data _U_)
{
if (pinfo->srcport < 3001 || pinfo->srcport > 3015
|| pinfo->destport < 3001 || pinfo->destport > 3015
|| pinfo->destport != pinfo->srcport)
return FALSE;
/*
* XXX - check for a valid LAPD address field.
*/
/*
* OK, check whether the control field looks valid.
*/
if (!check_xdlc_control(tvb, 2, NULL, NULL, FALSE, FALSE))
return FALSE;
dissect_lapd(tvb, pinfo, tree, data);
return TRUE;
}
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
};
static ei_register_info ei[] = {
{ &ei_lapd_abort, { "lapd.abort.expert", PI_PROTOCOL, PI_ERROR, "Formatted message", EXPFILL }},
{ &ei_lapd_checksum_bad, { "lapd.checksum_bad.expert", PI_CHECKSUM, PI_WARN, "Bad FCS", EXPFILL }},
};
module_t *lapd_module;
expert_module_t* expert_lapd;
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));
expert_lapd = expert_register_protocol(proto_lapd);
expert_register_field_array(expert_lapd, ei, array_length(ei));
register_dissector("lapd", dissect_lapd, proto_lapd);
lapd_sapi_dissector_table = register_dissector_table("lapd.sapi",
"LAPD SAPI", FT_UINT16, BASE_DEC, DISSECTOR_TABLE_NOT_ALLOW_DUPLICATE);
lapd_gsm_sapi_dissector_table = register_dissector_table("lapd.gsm.sapi",
"LAPD GSM SAPI", FT_UINT16, BASE_DEC, DISSECTOR_TABLE_NOT_ALLOW_DUPLICATE);
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);
dissector_add_uint("l2tp.pw_type", L2TPv3_PROTOCOL_LAPD, lapd_handle);
heur_dissector_add("udp", dissect_udp_lapd, "LAPD over UDP", "lapd_udp", proto_lapd, HEURISTIC_ENABLE);
register_dissector("lapd-bitstream", dissect_lapd_bitstream, proto_lapd);
lapd_bitstream_handle = find_dissector("lapd-bitstream");
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);
}
/*
* Editor modelines - http://www.wireshark.org/tools/modelines.html
*
* Local variables:
* c-basic-offset: 8
* tab-width: 8
* indent-tabs-mode: t
* End:
*
* vi: set shiftwidth=8 tabstop=8 noexpandtab:
* :indentSize=8:tabSize=8:noTabs=false:
*/
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