8181a83657
starting and ending frame number, and circuits with the same circuit ID are sorted by the starting frame number (the last circuit can have 0 as the ending frame number, meaning "unknown"), and, when looking up a circuit, we take a frame number as an argument and return the circuit that includes that frame. Add a new circuit ID type for X.25 virtual circuits, and use the circuit mechanism to keep track of the dissector for an X.25 virtual circuit rather than having a private mechanism. svn path=/trunk/; revision=6580
219 lines
5.8 KiB
C
219 lines
5.8 KiB
C
/* packet-isdn.c
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* Routines for ISDN packet disassembly
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*
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* $Id: packet-isdn.c,v 1.3 2002/11/08 01:00:04 guy Exp $
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*
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* Ethereal - Network traffic analyzer
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* By Gerald Combs <gerald@ethereal.com>
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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., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
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*/
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#ifdef HAVE_CONFIG_H
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# include "config.h"
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#endif
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#include <stdio.h>
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#include <glib.h>
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#include <epan/packet.h>
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#include <epan/circuit.h>
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static int proto_isdn = -1;
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static int hf_isdn_channel = -1;
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static gint ett_isdn = -1;
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static dissector_handle_t lapd_handle;
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static dissector_handle_t ppp_hdlc_handle;
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static dissector_handle_t v120_handle;
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static dissector_handle_t data_handle;
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static const value_string channel_vals[] = {
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{ 0, "D" },
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{ 1, "B1" },
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{ 2, "B2" },
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{ 3, "B3" },
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{ 4, "B4" },
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{ 5, "B5" },
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{ 6, "B6" },
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{ 7, "B7" },
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{ 8, "B8" },
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{ 9, "B9" },
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{ 10, "B10" },
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{ 11, "B11" },
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{ 12, "B12" },
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{ 13, "B13" },
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{ 14, "B14" },
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{ 15, "B15" },
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{ 16, "B16" },
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{ 17, "B17" },
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{ 18, "B19" },
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{ 19, "B19" },
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{ 20, "B20" },
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{ 21, "B21" },
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{ 22, "B22" },
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{ 23, "B23" },
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{ 24, "B24" },
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{ 25, "B25" },
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{ 26, "B26" },
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{ 27, "B27" },
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{ 28, "B29" },
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{ 29, "B29" },
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{ 30, "B30" },
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{ 0, NULL }
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};
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static void
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dissect_isdn(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
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{
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proto_tree *isdn_tree;
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proto_item *ti;
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static const char v120_sabme[3] = { 0x08, 0x01, 0x7F };
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static const char ppp[2] = { 0xFF, 0x03 };
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circuit_t *circuit;
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if (check_col(pinfo->cinfo, COL_PROTOCOL))
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col_set_str(pinfo->cinfo, COL_PROTOCOL, "ISDN");
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if (pinfo->pseudo_header->isdn.uton) {
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if (check_col(pinfo->cinfo, COL_RES_DL_DST))
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col_set_str(pinfo->cinfo, COL_RES_DL_DST, "Network");
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if (check_col(pinfo->cinfo, COL_RES_DL_SRC))
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col_set_str(pinfo->cinfo, COL_RES_DL_SRC, "User");
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} else {
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if (check_col(pinfo->cinfo, COL_RES_DL_DST))
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col_set_str(pinfo->cinfo, COL_RES_DL_DST, "User");
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if (check_col(pinfo->cinfo, COL_RES_DL_SRC))
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col_set_str(pinfo->cinfo, COL_RES_DL_SRC, "Network");
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}
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pinfo->ctype = CT_ISDN;
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pinfo->circuit_id = pinfo->pseudo_header->isdn.channel;
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if (tree) {
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ti = proto_tree_add_item(tree, proto_isdn, tvb, 0, 0, FALSE);
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isdn_tree = proto_item_add_subtree(ti, ett_isdn);
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proto_tree_add_uint(isdn_tree, hf_isdn_channel, tvb, 0, 0,
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pinfo->pseudo_header->isdn.channel);
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}
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/*
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* Set up a circuit for this channel, and assign it a dissector.
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*/
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circuit = find_circuit(pinfo->ctype, pinfo->circuit_id, pinfo->fd->num);
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if (circuit == NULL)
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circuit = circuit_new(pinfo->ctype, pinfo->circuit_id,
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pinfo->fd->num);
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if (circuit_get_dissector(circuit) == NULL) {
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/*
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* We don't yet know the type of traffic on the circuit.
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*/
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switch (pinfo->pseudo_header->isdn.channel) {
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case 0:
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/*
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* D-channel. Treat it as LAPD.
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*/
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circuit_set_dissector(circuit, lapd_handle);
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break;
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default:
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/*
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* B-channel.
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*
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* We don't know yet whether the datastream is
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* V.120 or not; this heuristic tries to figure
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* that out.
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*
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* We cannot glean this from the Q.931 SETUP message,
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* because no commercial V.120 implementation I've
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* seen actually sets the V.120 protocol discriminator
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* (that, or I'm misreading the spec badly).
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*
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* TODO: close the circuit after a close on the B
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* channel is detected.
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*
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* -Bert Driehuis (from the i4btrace reader;
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* this heuristic was moved from there to
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* here)
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*
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* XXX - I don't know that one can guarantee that
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* the SABME will appear in the first frame on
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* the channels, so we probably can't just say
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* "it must be PPP" if we don't immediately see
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* the V.120 SABME frame, so we do so only if
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* we see the 0xFF 0x03. Unfortunately, that
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* won't do the right thing if the PPP-over-HDLC
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* headers aren't being used....
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*/
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if (tvb_bytes_exist(tvb, 0, 3) &&
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tvb_memeql(tvb, 0, v120_sabme, 3) == 0) {
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/*
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* We assume this is V.120.
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*/
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circuit_set_dissector(circuit, v120_handle);
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} else if (tvb_bytes_exist(tvb, 0, 2) &&
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tvb_memeql(tvb, 0, ppp, 2) == 0) {
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/*
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* We assume this is PPP.
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*/
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circuit_set_dissector(circuit, ppp_hdlc_handle);
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}
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break;
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}
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}
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if (!try_circuit_dissector(pinfo->ctype, pinfo->circuit_id,
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pinfo->fd->num, tvb, pinfo, tree))
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call_dissector(data_handle, tvb, pinfo, tree);
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}
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void
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proto_register_isdn(void)
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{
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static hf_register_info hf[] = {
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{ &hf_isdn_channel,
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{ "Channel", "isdn.channel", FT_UINT8, BASE_DEC,
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VALS(channel_vals), 0x0, "", HFILL }},
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};
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static gint *ett[] = {
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&ett_isdn,
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};
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proto_isdn = proto_register_protocol("ISDN", "ISDN", "isdn");
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proto_register_field_array(proto_isdn, hf, array_length(hf));
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proto_register_subtree_array(ett, array_length(ett));
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}
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void
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proto_reg_handoff_isdn(void)
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{
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dissector_handle_t isdn_handle;
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/*
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* Get handles for the LAPD, PPP, and V.120 dissectors.
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*/
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lapd_handle = find_dissector("lapd");
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ppp_hdlc_handle = find_dissector("ppp_hdlc");
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v120_handle = find_dissector("v120");
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data_handle = find_dissector("data");
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isdn_handle = create_dissector_handle(dissect_isdn, proto_isdn);
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dissector_add("wtap_encap", WTAP_ENCAP_ISDN, isdn_handle);
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}
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