forked from osmocom/wireshark
![Guy Harris](/assets/img/avatar_default.png)
This reverts commit ba202ef362
.
Creating endpoints, and corresponding conversations, for protocols atop which TCP or UDP runs can potentially cause attempts to look up the conversation to find the conversation for that protocol rather than for TCP/UDP, which can confuse protocols running atop TCP or UDP.
Change-Id: I3ca522e54e67cc4f996d0ee841c6bb40ee6a9976
Reviewed-on: https://code.wireshark.org/review/28912
Reviewed-by: Guy Harris <guy@alum.mit.edu>
245 lines
5.9 KiB
C
245 lines
5.9 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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* SPDX-License-Identifier: GPL-2.0-or-later
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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/conversation.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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conversation_t *conv;
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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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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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conv = find_or_create_conversation_by_id(pinfo, ENDPOINT_ISDN,
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pinfo->pseudo_header->isdn.channel);
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if (conversation_get_dissector(conv, 0) == 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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conversation_set_dissector(conv, lapd_handle);
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break;
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case DCHANNEL_DPNSS:
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conversation_set_dissector(conv,
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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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conversation_set_dissector(conv, 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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conversation_set_dissector(conv, 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_conversation_dissector_by_id(ENDPOINT_ISDN, pinfo->pseudo_header->isdn.channel,
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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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