1 /* packet-mrdisc.c 2001 Ronnie Sahlberg <rsahlber@bigpond.net.au>
2 * Routines for IGMP/MRDISC packet disassembly
4 * $Id: packet-mrdisc.c,v 1.2 2001/07/16 05:16:57 guy Exp $
6 * Ethereal - Network traffic analyzer
7 * By Gerald Combs <gerald@ethereal.com>
8 * Copyright 1998 Gerald Combs
10 * This program is free software; you can redistribute it and/or
11 * modify it under the terms of the GNU General Public License
12 * as published by the Free Software Foundation; either version 2
13 * of the License, or (at your option) any later version.
15 * This program is distributed in the hope that it will be useful,
16 * but WITHOUT ANY WARRANTY; without even the implied warranty of
17 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
18 * GNU General Public License for more details.
20 * You should have received a copy of the GNU General Public License
21 * along with this program; if not, write to the Free Software
22 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
34 MRDISC : IGMP Multicast Router DISCovery
35 Defined in draft-ietf-idmr-igmp-mrdisc-06.txt
36 TTL==1 and IP.DST==224.0.0.2 for all packets.
43 #ifdef HAVE_SYS_TYPES_H
44 # include <sys/types.h>
53 #include "packet-mrdisc.h"
56 static int proto_mrdisc = -1;
57 static int hf_checksum = -1;
58 static int hf_checksum_bad = -1;
59 static int hf_type = -1;
60 static int hf_advint = -1;
61 static int hf_numopts = -1;
62 static int hf_options = -1;
63 static int hf_option = -1;
64 static int hf_option_len = -1;
65 static int hf_qi = -1;
66 static int hf_rv = -1;
67 static int hf_option_bytes = -1;
69 static int ett_mrdisc = -1;
70 static int ett_options = -1;
72 #define MRDISC_MRA 0x24
73 #define MRDISC_MRS 0x25
74 #define MRDISC_MRT 0x26
75 static const value_string mrdisc_types[] = {
76 {MRDISC_MRA, "Multicast Router Advertisement"},
77 {MRDISC_MRS, "Multicast Router Solicitation"},
78 {MRDISC_MRT, "Multicast Router Termination"},
82 #define MRDISC_QI 0x01
83 #define MRDISC_RV 0x02
84 static const value_string mrdisc_options[] = {
85 {MRDISC_QI, "Query Interval"},
86 {MRDISC_RV, "Robustness Variable"},
91 static void mrdisc_checksum(proto_tree *tree,tvbuff_t *tvb, int len)
93 guint16 cksum,hdrcksum;
96 cksum_vec[0].ptr = tvb_get_ptr(tvb, 0, len);
97 cksum_vec[0].len = len;
99 hdrcksum = tvb_get_ntohs(tvb, 2);
100 cksum = in_cksum(&cksum_vec[0],1);
103 proto_tree_add_uint_format(tree, hf_checksum, tvb, 2, 2, hdrcksum, "Header checksum: 0x%04x (correct)", hdrcksum);
105 proto_tree_add_item_hidden(tree, hf_checksum_bad, tvb, 2, 2, TRUE);
106 proto_tree_add_uint_format(tree, hf_checksum, tvb, 2, 2, hdrcksum, "Header checksum: 0x%04x (incorrect, should be 0x%04x)", hdrcksum,in_cksum_shouldbe(hdrcksum,cksum));
114 dissect_mrdisc_mra(tvbuff_t *tvb, packet_info *pinfo, proto_tree *parent_tree, int offset)
118 /* Advertising Interval */
119 proto_tree_add_item(parent_tree, hf_advint, tvb, offset, 1, FALSE);
123 mrdisc_checksum(parent_tree, tvb, tvb_length_remaining(tvb, 0));
126 /* skip unused bytes */
129 /* number of options */
130 num = tvb_get_ntohs(tvb, offset);
131 proto_tree_add_uint(parent_tree, hf_numopts, tvb,
135 /* process any options */
140 int old_offset = offset;
142 item = proto_tree_add_item(parent_tree, hf_options,
143 tvb, offset, 0, FALSE);
144 tree = proto_item_add_subtree(item, ett_options);
146 type = tvb_get_guint8(tvb, offset);
147 proto_tree_add_uint(tree, hf_option, tvb, offset, 1, type);
150 len = tvb_get_guint8(tvb, offset);
151 proto_tree_add_uint(tree, hf_option_len, tvb, offset, 1, len);
157 proto_item_set_text(item,"Option: %s == %d",
158 val_to_str(type, mrdisc_options, "unknown %x"),
159 tvb_get_ntohs(tvb, offset));
162 proto_tree_add_item(tree, hf_qi, tvb, offset, len,
168 proto_item_set_text(item,"Option: %s == %d",
169 val_to_str(type, mrdisc_options, "unknown %x"),
170 tvb_get_ntohs(tvb, offset));
173 proto_tree_add_item(tree, hf_rv, tvb, offset, len,
179 proto_item_set_text(item,"Option: unknown");
182 proto_tree_add_item(tree, hf_option_bytes,
183 tvb, offset, len, FALSE);
187 proto_item_set_len(item, offset-old_offset);
196 dissect_mrdisc_mrst(tvbuff_t *tvb, packet_info *pinfo, proto_tree *parent_tree, int offset)
198 /* skip reserved byte */
202 mrdisc_checksum(parent_tree, tvb, tvb_length_remaining(tvb, 0));
209 /* This function is only called from the IGMP dissector */
211 dissect_mrdisc(tvbuff_t *tvb, packet_info *pinfo, proto_tree *parent_tree, int offset)
217 if (!proto_is_protocol_enabled(proto_mrdisc)) {
218 /* we are not enabled, skip entire packet to be nice
219 to the igmp layer. (so clicking on IGMP will display the data)
221 return offset+tvb_length_remaining(tvb, offset);
224 item = proto_tree_add_item(parent_tree, proto_mrdisc, tvb, offset, 0, FALSE);
225 tree = proto_item_add_subtree(item, ett_mrdisc);
228 if (check_col(pinfo->fd, COL_PROTOCOL)) {
229 col_set_str(pinfo->fd, COL_PROTOCOL, "MRDISC");
231 if (check_col(pinfo->fd, COL_INFO)) {
232 col_clear(pinfo->fd, COL_INFO);
236 type = tvb_get_guint8(tvb, offset);
237 if (check_col(pinfo->fd, COL_INFO)) {
238 col_add_fstr(pinfo->fd, COL_INFO,
239 "%s",val_to_str(type, mrdisc_types,
240 "Unknown Type:0x%02x"));
243 /* type of command */
244 proto_tree_add_uint(tree, hf_type, tvb, offset, 1, type);
249 offset = dissect_mrdisc_mra(tvb, pinfo, tree, offset);
253 /* MRS and MRT packets looks the same */
254 offset = dissect_mrdisc_mrst(tvb, pinfo, tree, offset);
262 proto_register_mrdisc(void)
264 static hf_register_info hf[] = {
266 { "Type", "mrdisc.type", FT_UINT8, BASE_HEX,
267 VALS(mrdisc_types), 0, "MRDISC Packet Type", HFILL }},
270 { "Checksum", "mrdisc.checksum", FT_UINT16, BASE_HEX,
271 NULL, 0, "MRDISC Checksum", HFILL }},
274 { "Bad Checksum", "mrdisc.checksum_bad", FT_BOOLEAN, BASE_NONE,
275 NULL, 0, "Bad MRDISC Checksum", HFILL }},
278 { "Advertising Interval", "mrdisc.adv_int", FT_UINT8, BASE_DEC,
279 NULL, 0, "MRDISC Advertising Interval in seconds", HFILL }},
282 { "Number Of Options", "mrdisc.num_opts", FT_UINT16, BASE_DEC,
283 NULL, 0, "MRDISC Number Of Options", HFILL }},
286 { "Options", "mrdisc.options", FT_NONE, BASE_NONE,
287 NULL, 0, "MRDISC Options", HFILL }},
290 { "Option", "mrdisc.option", FT_UINT8, BASE_DEC,
291 VALS(mrdisc_options), 0, "MRDISC Option Type", HFILL }},
294 { "Length", "mrdisc.opt_len", FT_UINT8, BASE_DEC,
295 NULL, 0, "MRDISC Option Length", HFILL }},
298 { "Query Interval", "mrdisc.query_int", FT_UINT16, BASE_DEC,
299 NULL, 0, "MRDISC Query Interval", HFILL }},
302 { "Robustness Variable", "mrdisc.rob_var", FT_UINT16, BASE_DEC,
303 NULL, 0, "MRDISC Robustness Variable", HFILL }},
306 { "Data", "mrdisc.option_data", FT_BYTES, BASE_NONE,
307 NULL, 0, "MRDISC Unknown Option Data", HFILL }},
310 static gint *ett[] = {
315 proto_mrdisc = proto_register_protocol("Multicast Router DISCovery protocol",
317 proto_register_field_array(proto_mrdisc, hf, array_length(hf));
318 proto_register_subtree_array(ett, array_length(ett));