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-rw-r--r--epan/dissectors/packet-lapb.c250
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diff --git a/epan/dissectors/packet-lapb.c b/epan/dissectors/packet-lapb.c
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+++ b/epan/dissectors/packet-lapb.c
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+/* packet-lapb.c
+ * Routines for lapb frame disassembly
+ * Olivier Abad <oabad@noos.fr>
+ *
+ * $Id$
+ *
+ * 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"
+
+static int proto_lapb = -1;
+static int hf_lapb_address = -1;
+static int hf_lapb_control = -1;
+static int hf_lapb_n_r = -1;
+static int hf_lapb_n_s = -1;
+static int hf_lapb_p = -1;
+static int hf_lapb_f = -1;
+static int hf_lapb_s_ftype = -1;
+static int hf_lapb_u_modifier_cmd = -1;
+static int hf_lapb_u_modifier_resp = -1;
+static int hf_lapb_ftype_i = -1;
+static int hf_lapb_ftype_s_u = -1;
+
+static gint ett_lapb = -1;
+static gint ett_lapb_control = -1;
+
+static dissector_handle_t x25_dir_handle;
+static dissector_handle_t x25_handle;
+
+static const xdlc_cf_items lapb_cf_items = {
+ &hf_lapb_n_r,
+ &hf_lapb_n_s,
+ &hf_lapb_p,
+ &hf_lapb_f,
+ &hf_lapb_s_ftype,
+ &hf_lapb_u_modifier_cmd,
+ &hf_lapb_u_modifier_resp,
+ &hf_lapb_ftype_i,
+ &hf_lapb_ftype_s_u
+};
+
+static void
+dissect_lapb(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
+{
+ proto_tree *lapb_tree, *ti;
+ int is_response;
+ guint8 byte0;
+ tvbuff_t *next_tvb;
+
+ if (check_col(pinfo->cinfo, COL_PROTOCOL))
+ col_set_str(pinfo->cinfo, COL_PROTOCOL, "LAPB");
+ if (check_col(pinfo->cinfo, COL_INFO))
+ col_clear(pinfo->cinfo, COL_INFO);
+
+ switch (pinfo->p2p_dir) {
+
+ case P2P_DIR_SENT:
+ if(check_col(pinfo->cinfo, COL_RES_DL_SRC))
+ col_set_str(pinfo->cinfo, COL_RES_DL_SRC, "DTE");
+ if(check_col(pinfo->cinfo, COL_RES_DL_DST))
+ col_set_str(pinfo->cinfo, COL_RES_DL_DST, "DCE");
+ break;
+
+ case P2P_DIR_RECV:
+ if(check_col(pinfo->cinfo, COL_RES_DL_SRC))
+ col_set_str(pinfo->cinfo, COL_RES_DL_SRC, "DCE");
+ if(check_col(pinfo->cinfo, COL_RES_DL_DST))
+ col_set_str(pinfo->cinfo, COL_RES_DL_DST, "DTE");
+ break;
+
+ default:
+ if(check_col(pinfo->cinfo, COL_RES_DL_SRC))
+ col_set_str(pinfo->cinfo, COL_RES_DL_SRC, "N/A");
+ if(check_col(pinfo->cinfo, COL_RES_DL_DST))
+ col_set_str(pinfo->cinfo, COL_RES_DL_DST, "N/A");
+ break;
+ }
+
+ byte0 = tvb_get_guint8(tvb, 0);
+
+ if (byte0 != 0x01 && byte0 != 0x03) /* invalid LAPB frame */
+ {
+ if (check_col(pinfo->cinfo, COL_INFO))
+ col_set_str(pinfo->cinfo, COL_INFO, "Invalid LAPB frame");
+ if (tree)
+ ti = proto_tree_add_protocol_format(tree, proto_lapb, tvb, 0, -1,
+ "Invalid LAPB frame");
+ return;
+ }
+
+ switch (pinfo->p2p_dir) {
+
+ case P2P_DIR_SENT:
+ if (byte0 == 0x03)
+ is_response = TRUE;
+ else
+ is_response = FALSE;
+ break;
+
+ case P2P_DIR_RECV:
+ if (byte0 == 0x01)
+ is_response = TRUE;
+ else
+ is_response = FALSE;
+ break;
+
+ default:
+ /*
+ * XXX - should we base this on the source and destination
+ * addresses? The problem is that we can tell one direction
+ * from another with that, but we can't say which is DTE->DCE
+ * and which is DCE->DTE.
+ */
+ is_response = FALSE;
+ break;
+ }
+
+ if (tree) {
+ ti = proto_tree_add_protocol_format(tree, proto_lapb, tvb, 0, 2,
+ "LAPB");
+ lapb_tree = proto_item_add_subtree(ti, ett_lapb);
+ proto_tree_add_uint_format(lapb_tree, hf_lapb_address, tvb, 0, 1, byte0,
+ "Address: 0x%02X", byte0);
+ }
+ else
+ lapb_tree = NULL;
+
+ dissect_xdlc_control(tvb, 1, pinfo, lapb_tree, hf_lapb_control,
+ ett_lapb_control, &lapb_cf_items, NULL, NULL, NULL,
+ is_response, FALSE, FALSE);
+
+ /* not end of frame ==> X.25 */
+ if (tvb_reported_length(tvb) > 2) {
+ next_tvb = tvb_new_subset(tvb, 2, -1, -1);
+ switch (pinfo->p2p_dir) {
+
+ case P2P_DIR_SENT:
+ case P2P_DIR_RECV:
+ call_dissector(x25_dir_handle, next_tvb, pinfo, tree);
+ break;
+
+ default:
+ call_dissector(x25_handle, next_tvb, pinfo, tree);
+ break;
+ }
+ }
+}
+
+void
+proto_register_lapb(void)
+{
+ static hf_register_info hf[] = {
+ { &hf_lapb_address,
+ { "Address Field", "lapb.address", FT_UINT8, BASE_HEX, NULL, 0x0,
+ "Address", HFILL }},
+
+ { &hf_lapb_control,
+ { "Control Field", "lapb.control", FT_UINT8, BASE_HEX, NULL, 0x0,
+ "Control field", HFILL }},
+
+ { &hf_lapb_n_r,
+ { "N(R)", "lapb.control.n_r", FT_UINT8, BASE_DEC,
+ NULL, XDLC_N_R_MASK, "", HFILL }},
+
+ { &hf_lapb_n_s,
+ { "N(S)", "lapb.control.n_s", FT_UINT8, BASE_DEC,
+ NULL, XDLC_N_S_MASK, "", HFILL }},
+
+ { &hf_lapb_p,
+ { "Poll", "lapb.control.p", FT_BOOLEAN, 8,
+ TFS(&flags_set_truth), XDLC_P_F, "", HFILL }},
+
+ { &hf_lapb_f,
+ { "Final", "lapb.control.f", FT_BOOLEAN, 8,
+ TFS(&flags_set_truth), XDLC_P_F, "", HFILL }},
+
+ { &hf_lapb_s_ftype,
+ { "Supervisory frame type", "lapb.control.s_ftype", FT_UINT8, BASE_HEX,
+ VALS(stype_vals), XDLC_S_FTYPE_MASK, "", HFILL }},
+
+ { &hf_lapb_u_modifier_cmd,
+ { "Command", "lapb.control.u_modifier_cmd", FT_UINT8, BASE_HEX,
+ VALS(modifier_vals_cmd), XDLC_U_MODIFIER_MASK, "", HFILL }},
+
+ { &hf_lapb_u_modifier_resp,
+ { "Response", "lapb.control.u_modifier_resp", FT_UINT8, BASE_HEX,
+ VALS(modifier_vals_resp), XDLC_U_MODIFIER_MASK, "", HFILL }},
+
+ { &hf_lapb_ftype_i,
+ { "Frame type", "lapb.control.ftype", FT_UINT8, BASE_HEX,
+ VALS(ftype_vals), XDLC_I_MASK, "", HFILL }},
+
+ { &hf_lapb_ftype_s_u,
+ { "Frame type", "lapb.control.ftype", FT_UINT8, BASE_HEX,
+ VALS(ftype_vals), XDLC_S_U_MASK, "", HFILL }},
+ };
+ static gint *ett[] = {
+ &ett_lapb,
+ &ett_lapb_control,
+ };
+
+ proto_lapb = proto_register_protocol("Link Access Procedure Balanced (LAPB)",
+ "LAPB", "lapb");
+ proto_register_field_array (proto_lapb, hf, array_length(hf));
+ proto_register_subtree_array(ett, array_length(ett));
+
+ register_dissector("lapb", dissect_lapb, proto_lapb);
+}
+
+void
+proto_reg_handoff_lapb(void)
+{
+ dissector_handle_t lapb_handle;
+
+ /*
+ * Get handles for the X.25 dissectors; we don't get an X.25
+ * pseudo-header for LAPB-over-Ethernet, but we do get it
+ * for raw LAPB.
+ */
+ x25_dir_handle = find_dissector("x.25_dir");
+ x25_handle = find_dissector("x.25");
+
+ lapb_handle = find_dissector("lapb");
+ dissector_add("wtap_encap", WTAP_ENCAP_LAPB, lapb_handle);
+}
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