forked from osmocom/wireshark
![Guy Harris](/assets/img/avatar_default.png)
This emphasizes that there is no such thing as *the* routine to construct a subset tvbuff; you need to choose one of tvb_new_subset_remaining() (if you want a new tvbuff that contains everything past a certain point in an existing tvbuff), tvb_new_subset_length() (if you want a subset that contains everything past a certain point, for some number of bytes, in an existing tvbuff), and tvb_new_subset_length_caplen() (for all other cases). Many of the calls to tvb_new_subset_length_caplen() should really be calling one of the other routines; that's the next step. (This also makes it easier to find the calls that need fixing.) Change-Id: Ieb3d676d8cda535451c119487d7cd3b559221f2b Reviewed-on: https://code.wireshark.org/review/19597 Reviewed-by: Guy Harris <guy@alum.mit.edu>
227 lines
6.4 KiB
C
227 lines
6.4 KiB
C
/* packet-turnchannel.c
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* Routines for TURN channel dissection (TURN negociation is handled
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* in the STUN2 dissector
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* Copyright 2008, 8x8 Inc. <petithug@8x8.com>
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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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* Please refer to the following specs for protocol detail:
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* - draft-ietf-behave-rfc3489bis-15
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* - draft-ietf-mmusic-ice-19
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* - draft-ietf-behave-nat-behavior-discovery-03
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* - draft-ietf-behave-turn-07
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* - draft-ietf-behave-turn-ipv6-03
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*/
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#include "config.h"
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#include <epan/packet.h>
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#include "packet-tcp.h"
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void proto_register_turnchannel(void);
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void proto_reg_handoff_turnchannel(void);
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/* heuristic subdissectors */
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static heur_dissector_list_t heur_subdissector_list;
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/* Initialize the protocol and registered fields */
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static int proto_turnchannel = -1;
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static int hf_turnchannel_id = -1;
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static int hf_turnchannel_len = -1;
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#define TURNCHANNEL_HDR_LEN ((guint)4)
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/* Initialize the subtree pointers */
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static gint ett_turnchannel = -1;
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static dissector_handle_t turnchannel_udp_handle;
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static int
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dissect_turnchannel_message(tvbuff_t *tvb, packet_info *pinfo,
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proto_tree *tree, void *data _U_)
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{
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guint len;
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guint16 channel_id;
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guint16 data_len;
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proto_item *ti;
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proto_tree *turnchannel_tree;
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heur_dtbl_entry_t *hdtbl_entry;
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len = tvb_captured_length(tvb);
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/* First, make sure we have enough data to do the check. */
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if (len < TURNCHANNEL_HDR_LEN) {
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return 0;
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}
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channel_id = tvb_get_ntohs(tvb, 0);
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data_len = tvb_get_ntohs(tvb, 2);
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if ((channel_id < 0x4000) || (channel_id > 0xFFFE)) {
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return 0;
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}
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if (len != TURNCHANNEL_HDR_LEN + data_len) {
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return 0;
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}
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/* Seems to be a decent TURN channel message */
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col_set_str(pinfo->cinfo, COL_PROTOCOL, "TURN CHANNEL");
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col_add_fstr(pinfo->cinfo, COL_INFO, "Channel Id 0x%x", channel_id);
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ti = proto_tree_add_item(tree, proto_turnchannel, tvb, 0, -1, ENC_NA);
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turnchannel_tree = proto_item_add_subtree(ti, ett_turnchannel);
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proto_tree_add_uint(turnchannel_tree, hf_turnchannel_id, tvb, 0, 2, channel_id);
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proto_tree_add_uint(turnchannel_tree, hf_turnchannel_len, tvb, 2, 2, data_len);
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if (len > TURNCHANNEL_HDR_LEN) {
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tvbuff_t *next_tvb;
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guint reported_len, new_len;
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new_len = tvb_captured_length_remaining(tvb, TURNCHANNEL_HDR_LEN);
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reported_len = tvb_reported_length_remaining(tvb,
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TURNCHANNEL_HDR_LEN);
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if (data_len < reported_len) {
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reported_len = data_len;
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}
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next_tvb = tvb_new_subset_length_caplen(tvb, TURNCHANNEL_HDR_LEN, new_len,
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reported_len);
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if (!dissector_try_heuristic(heur_subdissector_list,
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next_tvb, pinfo, tree, &hdtbl_entry, NULL)) {
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call_data_dissector(next_tvb, pinfo, tree);
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}
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}
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return tvb_captured_length(tvb);
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}
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static guint
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get_turnchannel_message_len(packet_info *pinfo _U_, tvbuff_t *tvb,
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int offset, void *data _U_)
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{
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return (guint)tvb_get_ntohs(tvb, offset+2) + TURNCHANNEL_HDR_LEN;
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}
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static int
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dissect_turnchannel_tcp(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void* data)
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{
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tcp_dissect_pdus(tvb, pinfo, tree, TRUE, TURNCHANNEL_HDR_LEN,
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get_turnchannel_message_len, dissect_turnchannel_message, data);
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return tvb_captured_length(tvb);
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}
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static gboolean
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dissect_turnchannel_heur(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void *data _U_)
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{
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guint len;
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guint16 channel_id;
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guint16 data_len;
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len = tvb_captured_length(tvb);
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/* First, make sure we have enough data to do the check. */
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if (len < TURNCHANNEL_HDR_LEN) {
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return FALSE;
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}
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channel_id = tvb_get_ntohs(tvb, 0);
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data_len = tvb_get_ntohs(tvb, 2);
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if ((channel_id < 0x4000) || (channel_id > 0xFFFE)) {
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return FALSE;
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}
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if (len != TURNCHANNEL_HDR_LEN + data_len) {
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return FALSE;
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}
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return dissect_turnchannel_message(tvb, pinfo, tree, NULL);
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}
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void
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proto_register_turnchannel(void)
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{
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static hf_register_info hf[] = {
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{ &hf_turnchannel_id,
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{ "TURN Channel ID", "turnchannel.id", FT_UINT16,
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BASE_HEX, NULL, 0x0, NULL, HFILL }
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},
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{ &hf_turnchannel_len,
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{ "Data Length", "turnchannel.length", FT_UINT16,
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BASE_DEC, NULL, 0x0, NULL, HFILL }
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},
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};
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/* Setup protocol subtree array */
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static gint *ett[] = {
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&ett_turnchannel,
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};
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/* Register the protocol name and description */
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proto_turnchannel = proto_register_protocol("TURN Channel",
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"TURNCHANNEL", "turnchannel");
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turnchannel_udp_handle = register_dissector("turnchannel", dissect_turnchannel_message, proto_turnchannel);
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/* subdissectors */
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heur_subdissector_list = register_heur_dissector_list("turnchannel", proto_turnchannel);
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/* Required function calls to register the header fields and subtrees used */
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proto_register_field_array(proto_turnchannel, 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_turnchannel(void)
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{
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dissector_handle_t turnchannel_tcp_handle;
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turnchannel_tcp_handle = create_dissector_handle(dissect_turnchannel_tcp, proto_turnchannel);
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/* Register for "Decode As" in case STUN negotiation isn't captured */
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dissector_add_for_decode_as_with_preference("tcp.port", turnchannel_tcp_handle);
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dissector_add_for_decode_as_with_preference("udp.port", turnchannel_udp_handle);
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/* TURN negotiation is handled through STUN2 dissector (packet-stun.c),
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so only it should be able to determine if a packet is a TURN packet */
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heur_dissector_add("stun", dissect_turnchannel_heur, "TURN Channel over STUN", "turnchannel_stun", proto_turnchannel, HEURISTIC_ENABLE);
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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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