forked from osmocom/wireshark
251 lines
6.8 KiB
C
251 lines
6.8 KiB
C
/* packet-lapb.c
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* Routines for lapb frame disassembly
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* Olivier Abad <oabad@noos.fr>
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*
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* $Id: packet-lapb.c,v 1.42 2004/01/18 08:32:45 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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#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 int hf_lapb_n_r = -1;
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static int hf_lapb_n_s = -1;
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static int hf_lapb_p = -1;
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static int hf_lapb_f = -1;
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static int hf_lapb_s_ftype = -1;
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static int hf_lapb_u_modifier_cmd = -1;
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static int hf_lapb_u_modifier_resp = -1;
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static int hf_lapb_ftype_i = -1;
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static int hf_lapb_ftype_s_u = -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 dissector_handle_t x25_handle;
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static const xdlc_cf_items lapb_cf_items = {
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&hf_lapb_n_r,
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&hf_lapb_n_s,
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&hf_lapb_p,
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&hf_lapb_f,
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&hf_lapb_s_ftype,
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&hf_lapb_u_modifier_cmd,
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&hf_lapb_u_modifier_resp,
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&hf_lapb_ftype_i,
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&hf_lapb_ftype_s_u
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};
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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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switch (pinfo->p2p_dir) {
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case P2P_DIR_SENT:
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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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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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break;
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case P2P_DIR_RECV:
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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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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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break;
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default:
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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, "N/A");
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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, "N/A");
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break;
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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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switch (pinfo->p2p_dir) {
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case P2P_DIR_SENT:
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if (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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break;
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case P2P_DIR_RECV:
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if (byte0 == 0x01)
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is_response = TRUE;
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else
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is_response = FALSE;
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break;
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default:
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/*
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* XXX - should we base this on the source and destination
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* addresses? The problem is that we can tell one direction
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* from another with that, but we can't say which is DTE->DCE
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* and which is DCE->DTE.
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*/
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is_response = FALSE;
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break;
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}
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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, &lapb_cf_items, NULL, NULL, NULL,
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is_response, FALSE, 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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switch (pinfo->p2p_dir) {
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case P2P_DIR_SENT:
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case P2P_DIR_RECV:
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call_dissector(x25_dir_handle, next_tvb, pinfo, tree);
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break;
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default:
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call_dissector(x25_handle, next_tvb, pinfo, tree);
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break;
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}
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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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{ &hf_lapb_n_r,
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{ "N(R)", "lapb.control.n_r", FT_UINT8, BASE_DEC,
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NULL, XDLC_N_R_MASK, "", HFILL }},
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{ &hf_lapb_n_s,
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{ "N(S)", "lapb.control.n_s", FT_UINT8, BASE_DEC,
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NULL, XDLC_N_S_MASK, "", HFILL }},
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{ &hf_lapb_p,
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{ "Poll", "lapb.control.p", FT_BOOLEAN, 8,
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TFS(&flags_set_truth), XDLC_P_F, "", HFILL }},
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{ &hf_lapb_f,
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{ "Final", "lapb.control.f", FT_BOOLEAN, 8,
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TFS(&flags_set_truth), XDLC_P_F, "", HFILL }},
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{ &hf_lapb_s_ftype,
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{ "Supervisory frame type", "lapb.control.s_ftype", FT_UINT8, BASE_HEX,
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VALS(stype_vals), XDLC_S_FTYPE_MASK, "", HFILL }},
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{ &hf_lapb_u_modifier_cmd,
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{ "Command", "lapb.control.u_modifier_cmd", FT_UINT8, BASE_HEX,
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VALS(modifier_vals_cmd), XDLC_U_MODIFIER_MASK, "", HFILL }},
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{ &hf_lapb_u_modifier_resp,
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{ "Response", "lapb.control.u_modifier_resp", FT_UINT8, BASE_HEX,
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VALS(modifier_vals_resp), XDLC_U_MODIFIER_MASK, "", HFILL }},
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{ &hf_lapb_ftype_i,
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{ "Frame type", "lapb.control.ftype", FT_UINT8, BASE_HEX,
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VALS(ftype_vals), XDLC_I_MASK, "", HFILL }},
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{ &hf_lapb_ftype_s_u,
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{ "Frame type", "lapb.control.ftype", FT_UINT8, BASE_HEX,
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VALS(ftype_vals), XDLC_S_U_MASK, "", 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 handles for the X.25 dissectors; we don't get an X.25
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* pseudo-header for LAPB-over-Ethernet, but we do get it
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* for raw LAPB.
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*/
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x25_dir_handle = find_dissector("x.25_dir");
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x25_handle = find_dissector("x.25");
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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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