1e60d63c8c
This saves many dissectors the need to find the data dissector and store a handle to it. There were also some that were finding it, but not using it. For others this was the only reason for their handoff function, so it could be eliminated. Change-Id: I5d3f951ee1daa3d30c060d21bd12bbc881a8027b Reviewed-on: https://code.wireshark.org/review/14530 Petri-Dish: Michael Mann <mmann78@netscape.net> Reviewed-by: Michael Mann <mmann78@netscape.net>
262 lines
6.8 KiB
C
262 lines
6.8 KiB
C
/* packet-isdn.c
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* Routines for ISDN packet disassembly
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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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#include "config.h"
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#include <epan/packet.h>
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#include <epan/prefs.h>
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#include <wiretap/wtap.h>
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#include <epan/circuit.h>
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void proto_register_isdn(void);
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void proto_reg_handoff_isdn(void);
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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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/*
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* Protocol used on the D channel.
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*/
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#define DCHANNEL_LAPD 0 /* LAPD */
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#define DCHANNEL_DPNSS 1 /* DPNSS link layer */
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static const enum_val_t dchannel_protocol_options[] = {
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{ "lapd", "LAPD", DCHANNEL_LAPD },
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{ "DPNSS", "DPNSS", DCHANNEL_DPNSS },
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{ NULL, NULL, 0 }
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};
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static int dchannel_protocol = DCHANNEL_LAPD;
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static dissector_handle_t lapd_handle;
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static dissector_handle_t dpnss_link_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 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 int
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dissect_isdn(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void* data _U_)
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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 guint8 v120_sabme[3] = { 0x08, 0x01, 0x7F };
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static const guint8 ppp[2] = { 0xFF, 0x03 };
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circuit_t *circuit;
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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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col_set_str(pinfo->cinfo, COL_RES_DL_DST, "Network");
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col_set_str(pinfo->cinfo, COL_RES_DL_SRC, "User");
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} else {
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col_set_str(pinfo->cinfo, COL_RES_DL_DST, "User");
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col_set_str(pinfo->cinfo, COL_RES_DL_SRC, "Network");
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}
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/* XXX - Are these still needed? We've used other values where necessary */
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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, ENC_NA);
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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(CT_ISDN, pinfo->pseudo_header->isdn.channel, pinfo->num);
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if (circuit == NULL)
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circuit = circuit_new(CT_ISDN, pinfo->pseudo_header->isdn.channel, pinfo->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. Dissect it with whatever protocol
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* the user specified, or the default of LAPD if
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* they didn't specify one.
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*/
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switch (dchannel_protocol) {
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case DCHANNEL_LAPD:
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circuit_set_dissector(circuit, lapd_handle);
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break;
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case DCHANNEL_DPNSS:
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circuit_set_dissector(circuit,
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dpnss_link_handle);
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break;
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}
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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_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_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(CT_ISDN, pinfo->pseudo_header->isdn.channel,
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pinfo->num, tvb, pinfo, tree, NULL))
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call_data_dissector(tvb, pinfo, tree);
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return tvb_captured_length(tvb);
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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, NULL, 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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module_t *isdn_module;
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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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isdn_module = prefs_register_protocol(proto_isdn, NULL);
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prefs_register_enum_preference(isdn_module, "dchannel_protocol",
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"D-channel protocol",
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"The protocol running on the D channel",
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&dchannel_protocol, dchannel_protocol_options, FALSE);
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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, DPNSS link-layer, PPP, and V.120
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* dissectors.
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*/
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lapd_handle = find_dissector("lapd");
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dpnss_link_handle = find_dissector("dpnss_link");
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ppp_hdlc_handle = find_dissector("ppp_hdlc");
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v120_handle = find_dissector("v120");
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isdn_handle = create_dissector_handle(dissect_isdn, proto_isdn);
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dissector_add_uint("wtap_encap", WTAP_ENCAP_ISDN, isdn_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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