![Guy Harris](/assets/img/avatar_default.png)
"struct x25_phdr" to "wiretap/wtap.h". Have two X.25 dissectors, one of which assumes that there's a "struct x25_phdr" pseudo-header and one of which doesn't; the former uses the information in that pseudo-header to determine whether the packet is DTE->DCE or DCE->DTE, and the latter assumes it has no clue whether the packet is DTE->DCE or DCE->TDE. Use the former one in the LAPB dissector, and the latter one in the XOT dissector and in the LLC dissector table. In the X.25-over-TCP dissector, handle multiple X.25 packets per TCP segment, and handle X.25 packets split across TCP segments. svn path=/trunk/; revision=5134
152 lines
4.3 KiB
C
152 lines
4.3 KiB
C
/* packet-lapb.c
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* Routines for lapb frame disassembly
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* Olivier Abad <oabad@cybercable.fr>
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*
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* $Id: packet-lapb.c,v 1.35 2002/04/09 08:15:02 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
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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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#ifdef HAVE_SYS_TYPES_H
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# include <sys/types.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 <string.h>
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#include <epan/packet.h>
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#include "xdlc.h"
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static int proto_lapb = -1;
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static int hf_lapb_address = -1;
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static int hf_lapb_control = -1;
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static gint ett_lapb = -1;
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static gint ett_lapb_control = -1;
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static dissector_handle_t x25_dir_handle;
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static void
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dissect_lapb(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
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{
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proto_tree *lapb_tree, *ti;
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int is_response;
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guint8 byte0;
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tvbuff_t *next_tvb;
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if (check_col(pinfo->cinfo, COL_PROTOCOL))
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col_set_str(pinfo->cinfo, COL_PROTOCOL, "LAPB");
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if (check_col(pinfo->cinfo, COL_INFO))
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col_clear(pinfo->cinfo, COL_INFO);
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if (pinfo->pseudo_header->x25.flags & FROM_DCE) {
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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, "DTE");
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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, "DCE");
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}
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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, "DCE");
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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, "DTE");
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}
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byte0 = tvb_get_guint8(tvb, 0);
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if (byte0 != 0x01 && byte0 != 0x03) /* invalid LAPB frame */
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{
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if (check_col(pinfo->cinfo, COL_INFO))
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col_set_str(pinfo->cinfo, COL_INFO, "Invalid LAPB frame");
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if (tree)
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ti = proto_tree_add_protocol_format(tree, proto_lapb, tvb, 0, -1,
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"Invalid LAPB frame");
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return;
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}
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if (((pinfo->pseudo_header->x25.flags & FROM_DCE) && byte0 == 0x01) ||
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(!(pinfo->pseudo_header->x25.flags & FROM_DCE) && byte0 == 0x03))
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is_response = TRUE;
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else
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is_response = FALSE;
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if (tree) {
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ti = proto_tree_add_protocol_format(tree, proto_lapb, tvb, 0, 2,
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"LAPB");
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lapb_tree = proto_item_add_subtree(ti, ett_lapb);
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proto_tree_add_uint_format(lapb_tree, hf_lapb_address, tvb, 0, 1, byte0,
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"Address: 0x%02X", byte0);
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}
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else
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lapb_tree = NULL;
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dissect_xdlc_control(tvb, 1, pinfo, lapb_tree, hf_lapb_control,
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ett_lapb_control, is_response, FALSE);
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/* not end of frame ==> X.25 */
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if (tvb_reported_length(tvb) > 2) {
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next_tvb = tvb_new_subset(tvb, 2, -1, -1);
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call_dissector(x25_dir_handle, next_tvb, pinfo, tree);
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}
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}
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void
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proto_register_lapb(void)
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{
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static hf_register_info hf[] = {
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{ &hf_lapb_address,
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{ "Address Field", "lapb.address", FT_UINT8, BASE_HEX, NULL, 0x0,
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"Address", HFILL }},
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{ &hf_lapb_control,
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{ "Control Field", "lapb.control", FT_UINT8, BASE_HEX, NULL, 0x0,
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"Control field", HFILL }},
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};
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static gint *ett[] = {
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&ett_lapb,
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&ett_lapb_control,
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};
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proto_lapb = proto_register_protocol("Link Access Procedure Balanced (LAPB)",
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"LAPB", "lapb");
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proto_register_field_array (proto_lapb, hf, array_length(hf));
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proto_register_subtree_array(ett, array_length(ett));
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register_dissector("lapb", dissect_lapb, proto_lapb);
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}
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void
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proto_reg_handoff_lapb(void)
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{
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dissector_handle_t lapb_handle;
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/*
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* Get a handle for the X.25 dissector; we will be getting an
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* X.25 pseudo-header, so call the dissector that can handle it.
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*/
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x25_dir_handle = find_dissector("x.25_dir");
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lapb_handle = find_dissector("lapb");
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dissector_add("wtap_encap", WTAP_ENCAP_LAPB, lapb_handle);
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}
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