forked from osmocom/wireshark
f4248f455d
Ensure "relevant function" logic works for loopback packets containing multiple forwarding addresses. svn path=/trunk/; revision=17689
176 lines
4.7 KiB
C
176 lines
4.7 KiB
C
/* packet-loop.c
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* Routines for Ethernet loopback/Configuration Test Protocol dissection
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*
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* See
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*
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* http://stuff.mit.edu/people/jhawk/ctp.html
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*
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* $Id$
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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 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., 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 <glib.h>
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#include <epan/packet.h>
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#include <epan/etypes.h>
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static int proto_loop = -1;
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static int hf_loop_skipcount = -1;
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static int hf_loop_function = -1;
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static int hf_loop_receipt_number = -1;
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static int hf_loop_forwarding_address = -1;
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static gint ett_loop = -1;
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static dissector_handle_t data_handle;
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#define FUNC_REPLY 1
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#define FUNC_FORWARD_DATA 2
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static const value_string function_vals[] = {
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{ FUNC_REPLY, "Reply" },
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{ FUNC_FORWARD_DATA, "Forward Data" },
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{ 0, NULL }
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};
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static void
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dissect_loop(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
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{
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proto_tree *loop_tree = NULL;
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proto_item *ti;
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guint16 function;
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int offset = 0;
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int skip_offset;
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gboolean set_info = TRUE;
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gboolean more_function;
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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, "LOOP");
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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 (tree) {
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ti = proto_tree_add_item(tree, proto_loop, tvb, offset, -1, FALSE);
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loop_tree = proto_item_add_subtree(ti, ett_loop);
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proto_tree_add_item(loop_tree, hf_loop_skipcount, tvb, offset, 2, TRUE);
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}
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skip_offset = 2 + tvb_get_letohs(tvb, offset);
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offset += 2;
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do {
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function = tvb_get_letohs(tvb, offset);
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if (offset == skip_offset) {
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if (check_col(pinfo->cinfo, COL_INFO)) {
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col_add_str(pinfo->cinfo, COL_INFO,
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val_to_str(function, function_vals, "Unknown function (%u)"));
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}
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if (tree)
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proto_tree_add_text(loop_tree, tvb, offset, 2, "Relevant function:");
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set_info = FALSE;
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}
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if (tree)
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proto_tree_add_uint(loop_tree, hf_loop_function, tvb, offset, 2, function);
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offset += 2;
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switch (function) {
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case FUNC_REPLY:
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if (tree)
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proto_tree_add_item(loop_tree, hf_loop_receipt_number, tvb, offset, 2,
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TRUE);
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offset += 2;
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more_function = FALSE;
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break;
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case FUNC_FORWARD_DATA:
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if (tree)
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proto_tree_add_item(loop_tree, hf_loop_forwarding_address, tvb, offset,
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6, FALSE);
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offset += 6;
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more_function = TRUE;
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break;
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default:
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more_function = FALSE;
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break;
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}
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} while (more_function);
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if (set_info && check_col(pinfo->cinfo, COL_INFO)) {
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col_add_str(pinfo->cinfo, COL_INFO, "No valid function found");
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}
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if (tvb_length_remaining(tvb, offset) > 0)
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{
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next_tvb = tvb_new_subset(tvb, offset, -1, -1);
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call_dissector(data_handle, next_tvb, pinfo, tree);
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}
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}
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void
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proto_register_loop(void)
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{
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static hf_register_info hf[] = {
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{ &hf_loop_skipcount,
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{ "skipCount", "loop.skipcount",
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FT_UINT16, BASE_DEC, NULL, 0x0,
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"", HFILL }},
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{ &hf_loop_function,
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{ "Function", "loop.function",
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FT_UINT16, BASE_DEC, VALS(function_vals), 0x0,
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"", HFILL }},
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{ &hf_loop_receipt_number,
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{ "Receipt number", "loop.receipt_number",
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FT_UINT16, BASE_DEC, NULL, 0x0,
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"", HFILL }},
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{ &hf_loop_forwarding_address,
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{ "Forwarding address", "loop.forwarding_address",
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FT_ETHER, BASE_NONE, NULL, 0x0,
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"", HFILL }},
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};
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static gint *ett[] = {
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&ett_loop,
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};
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proto_loop = proto_register_protocol("Configuration Test Protocol (loopback)",
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"LOOP", "loop");
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proto_register_field_array(proto_loop, 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_loop(void)
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{
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dissector_handle_t loop_handle;
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loop_handle = create_dissector_handle(dissect_loop, proto_loop);
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dissector_add("ethertype", ETHERTYPE_LOOP, loop_handle);
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data_handle = find_dissector("data");
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}
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