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Diffstat (limited to 'epan/dissectors/packet-lapd.c')
-rw-r--r-- | epan/dissectors/packet-lapd.c | 296 |
1 files changed, 296 insertions, 0 deletions
diff --git a/epan/dissectors/packet-lapd.c b/epan/dissectors/packet-lapd.c new file mode 100644 index 0000000000..d766047ef8 --- /dev/null +++ b/epan/dissectors/packet-lapd.c @@ -0,0 +1,296 @@ +/* packet-lapd.c + * Routines for LAPD frame disassembly + * Gilbert Ramirez <gram@alumni.rice.edu> + * + * $Id$ + * + * Ethereal - Network traffic analyzer + * By Gerald Combs <gerald@ethereal.com> + * Copyright 1998 + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation; either version 2 + * of the License, or (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. + */ + +#ifdef HAVE_CONFIG_H +# include "config.h" +#endif + +#include <stdio.h> +#include <glib.h> +#include <string.h> +#include <epan/packet.h> +#include "xdlc.h" + +#include "lapd_sapi.h" + +/* ISDN/LAPD references: + * + * http://www.cisco.com/univercd/cc/td/doc/cisintwk/ito_doc/isdn.htm + * http://www.ece.wpi.edu/courses/ee535/hwk11cd95/agrebe/agrebe.html + * http://www.acacia-net.com/Clarinet/Protocol/q9213o84.htm + */ + +static int proto_lapd = -1; +static int hf_lapd_address = -1; +static int hf_lapd_sapi = -1; +static int hf_lapd_cr = -1; +static int hf_lapd_ea1 = -1; +static int hf_lapd_tei = -1; +static int hf_lapd_ea2 = -1; +static int hf_lapd_control = -1; +static int hf_lapd_n_r = -1; +static int hf_lapd_n_s = -1; +static int hf_lapd_p = -1; +static int hf_lapd_p_ext = -1; +static int hf_lapd_f = -1; +static int hf_lapd_f_ext = -1; +static int hf_lapd_s_ftype = -1; +static int hf_lapd_u_modifier_cmd = -1; +static int hf_lapd_u_modifier_resp = -1; +static int hf_lapd_ftype_i = -1; +static int hf_lapd_ftype_s_u = -1; +static int hf_lapd_ftype_s_u_ext = -1; + +static gint ett_lapd = -1; +static gint ett_lapd_address = -1; +static gint ett_lapd_control = -1; + +static dissector_table_t lapd_sapi_dissector_table; + +static dissector_handle_t data_handle; +static dissector_handle_t tei_handle; + +/* + * Bits in the address field. + */ +#define LAPD_SAPI 0xfc00 /* Service Access Point Identifier */ +#define LAPD_SAPI_SHIFT 10 +#define LAPD_CR 0x0200 /* Command/Response bit */ +#define LAPD_EA1 0x0100 /* First Address Extension bit */ +#define LAPD_TEI 0x00fe /* Terminal Endpoint Identifier */ +#define LAPD_EA2 0x0001 /* Second Address Extension bit */ + +static const value_string lapd_sapi_vals[] = { + { LAPD_SAPI_Q931, "Q.931 Call control procedure" }, + { LAPD_SAPI_PM_Q931, "Packet mode Q.931 Call control procedure" }, + { LAPD_SAPI_X25, "X.25 Level 3 procedures" }, + { LAPD_SAPI_L2, "Layer 2 management procedures" }, + { 0, NULL } +}; + +/* Used only for U frames */ +static const xdlc_cf_items lapd_cf_items = { + NULL, + NULL, + &hf_lapd_p, + &hf_lapd_f, + NULL, + &hf_lapd_u_modifier_cmd, + &hf_lapd_u_modifier_resp, + NULL, + &hf_lapd_ftype_s_u +}; + +/* Used only for I and S frames */ +static const xdlc_cf_items lapd_cf_items_ext = { + &hf_lapd_n_r, + &hf_lapd_n_s, + &hf_lapd_p_ext, + &hf_lapd_f_ext, + &hf_lapd_s_ftype, + NULL, + NULL, + &hf_lapd_ftype_i, + &hf_lapd_ftype_s_u_ext +}; + +static void +dissect_lapd(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree) +{ + proto_tree *lapd_tree, *addr_tree; + proto_item *lapd_ti, *addr_ti; + guint16 control; + int lapd_header_len; + guint16 address, cr, sapi; + gboolean is_response; + tvbuff_t *next_tvb; + + if (check_col(pinfo->cinfo, COL_PROTOCOL)) + col_set_str(pinfo->cinfo, COL_PROTOCOL, "LAPD"); + if (check_col(pinfo->cinfo, COL_INFO)) + col_clear(pinfo->cinfo, COL_INFO); + + address = tvb_get_ntohs(tvb, 0); + cr = address & LAPD_CR; + sapi = (address & LAPD_SAPI) >> LAPD_SAPI_SHIFT; + lapd_header_len = 2; /* address */ + + if (pinfo->p2p_dir == P2P_DIR_SENT) { + is_response = cr ? TRUE : FALSE; + if(check_col(pinfo->cinfo, COL_RES_DL_DST)) + col_set_str(pinfo->cinfo, COL_RES_DL_DST, "Network"); + if(check_col(pinfo->cinfo, COL_RES_DL_SRC)) + col_set_str(pinfo->cinfo, COL_RES_DL_SRC, "User"); + } + else { + /* XXX - what if the direction is unknown? */ + is_response = cr ? FALSE : TRUE; + if(check_col(pinfo->cinfo, COL_RES_DL_DST)) + col_set_str(pinfo->cinfo, COL_RES_DL_DST, "User"); + if(check_col(pinfo->cinfo, COL_RES_DL_SRC)) + col_set_str(pinfo->cinfo, COL_RES_DL_SRC, "Network"); + } + + if (tree) { + lapd_ti = proto_tree_add_item(tree, proto_lapd, tvb, 0, -1, + FALSE); + lapd_tree = proto_item_add_subtree(lapd_ti, ett_lapd); + + addr_ti = proto_tree_add_uint(lapd_tree, hf_lapd_address, tvb, + 0, 2, address); + addr_tree = proto_item_add_subtree(addr_ti, ett_lapd_address); + + proto_tree_add_uint(addr_tree, hf_lapd_sapi,tvb, 0, 1, address); + proto_tree_add_uint(addr_tree, hf_lapd_cr, tvb, 0, 1, address); + proto_tree_add_uint(addr_tree, hf_lapd_ea1, tvb, 0, 1, address); + proto_tree_add_uint(addr_tree, hf_lapd_tei, tvb, 1, 1, address); + proto_tree_add_uint(addr_tree, hf_lapd_ea2, tvb, 1, 1, address); + } + else { + lapd_ti = NULL; + lapd_tree = NULL; + } + + control = dissect_xdlc_control(tvb, 2, pinfo, lapd_tree, hf_lapd_control, + ett_lapd_control, &lapd_cf_items, &lapd_cf_items_ext, NULL, NULL, + is_response, TRUE, FALSE); + lapd_header_len += XDLC_CONTROL_LEN(control, TRUE); + + if (tree) + proto_item_set_len(lapd_ti, lapd_header_len); + + next_tvb = tvb_new_subset(tvb, lapd_header_len, -1, -1); + if (XDLC_IS_INFORMATION(control)) { + /* call next protocol */ + if (!dissector_try_port(lapd_sapi_dissector_table, sapi, + next_tvb, pinfo, tree)) + call_dissector(data_handle,next_tvb, pinfo, tree); + } else + call_dissector(data_handle,next_tvb, pinfo, tree); +} + +void +proto_register_lapd(void) +{ + static hf_register_info hf[] = { + { &hf_lapd_address, + { "Address Field", "lapd.address", FT_UINT16, BASE_HEX, NULL, 0x0, + "Address", HFILL }}, + + { &hf_lapd_sapi, + { "SAPI", "lapd.sapi", FT_UINT16, BASE_DEC, VALS(lapd_sapi_vals), LAPD_SAPI, + "Service Access Point Identifier", HFILL }}, + + { &hf_lapd_cr, + { "C/R", "lapd.cr", FT_UINT16, BASE_DEC, NULL, LAPD_CR, + "Command/Response bit", HFILL }}, + + { &hf_lapd_ea1, + { "EA1", "lapd.ea1", FT_UINT16, BASE_DEC, NULL, LAPD_EA1, + "First Address Extension bit", HFILL }}, + + { &hf_lapd_tei, + { "TEI", "lapd.tei", FT_UINT16, BASE_DEC, NULL, LAPD_TEI, + "Terminal Endpoint Identifier", HFILL }}, + + { &hf_lapd_ea2, + { "EA2", "lapd.ea2", FT_UINT16, BASE_DEC, NULL, LAPD_EA2, + "Second Address Extension bit", HFILL }}, + + { &hf_lapd_control, + { "Control Field", "lapd.control", FT_UINT16, BASE_HEX, NULL, 0x0, + "Control field", HFILL }}, + + { &hf_lapd_n_r, + { "N(R)", "lapd.control.n_r", FT_UINT16, BASE_DEC, + NULL, XDLC_N_R_EXT_MASK, "", HFILL }}, + + { &hf_lapd_n_s, + { "N(S)", "lapd.control.n_s", FT_UINT16, BASE_DEC, + NULL, XDLC_N_S_EXT_MASK, "", HFILL }}, + + { &hf_lapd_p, + { "Poll", "lapd.control.p", FT_BOOLEAN, 8, + TFS(&flags_set_truth), XDLC_P_F, "", HFILL }}, + + { &hf_lapd_p_ext, + { "Poll", "lapd.control.p", FT_BOOLEAN, 16, + TFS(&flags_set_truth), XDLC_P_F_EXT, "", HFILL }}, + + { &hf_lapd_f, + { "Final", "lapd.control.f", FT_BOOLEAN, 8, + TFS(&flags_set_truth), XDLC_P_F, "", HFILL }}, + + { &hf_lapd_f_ext, + { "Final", "lapd.control.f", FT_BOOLEAN, 16, + TFS(&flags_set_truth), XDLC_P_F_EXT, "", HFILL }}, + + { &hf_lapd_s_ftype, + { "Supervisory frame type", "lapd.control.s_ftype", FT_UINT16, BASE_HEX, + VALS(stype_vals), XDLC_S_FTYPE_MASK, "", HFILL }}, + + { &hf_lapd_u_modifier_cmd, + { "Command", "lapd.control.u_modifier_cmd", FT_UINT8, BASE_HEX, + VALS(modifier_vals_cmd), XDLC_U_MODIFIER_MASK, "", HFILL }}, + + { &hf_lapd_u_modifier_resp, + { "Response", "lapd.control.u_modifier_resp", FT_UINT8, BASE_HEX, + VALS(modifier_vals_resp), XDLC_U_MODIFIER_MASK, "", HFILL }}, + + { &hf_lapd_ftype_i, + { "Frame type", "lapd.control.ftype", FT_UINT16, BASE_HEX, + VALS(ftype_vals), XDLC_I_MASK, "", HFILL }}, + + { &hf_lapd_ftype_s_u, + { "Frame type", "lapd.control.ftype", FT_UINT8, BASE_HEX, + VALS(ftype_vals), XDLC_S_U_MASK, "", HFILL }}, + + { &hf_lapd_ftype_s_u_ext, + { "Frame type", "lapd.control.ftype", FT_UINT16, BASE_HEX, + VALS(ftype_vals), XDLC_S_U_MASK, "", HFILL }}, + }; + static gint *ett[] = { + &ett_lapd, + &ett_lapd_address, + &ett_lapd_control, + }; + + proto_lapd = proto_register_protocol("Link Access Procedure, Channel D (LAPD)", + "LAPD", "lapd"); + proto_register_field_array (proto_lapd, hf, array_length(hf)); + proto_register_subtree_array(ett, array_length(ett)); + + register_dissector("lapd", dissect_lapd, proto_lapd); + + lapd_sapi_dissector_table = register_dissector_table("lapd.sapi", + "LAPD SAPI", FT_UINT16, BASE_DEC); +} + +void +proto_reg_handoff_lapd(void) +{ + data_handle = find_dissector("data"); + tei_handle = find_dissector("tei"); +} |