2 * Routines for BPDU (Spanning Tree Protocol) disassembly
4 * $Id: packet-bpdu.c,v 1.18 2001/01/03 06:55:27 guy Exp $
6 * Copyright 1999 Christophe Tronche <ch.tronche@computer.org>
8 * Ethereal - Network traffic analyzer
9 * By Gerald Combs <gerald@zing.org>
10 * Copyright 1998 Gerald Combs
13 * This program is free software; you can redistribute it and/or
14 * modify it under the terms of the GNU General Public License
15 * as published by the Free Software Foundation; either version 2
16 * of the License, or (at your option) any later version.
18 * This program is distributed in the hope that it will be useful,
19 * but WITHOUT ANY WARRANTY; without even the implied warranty of
20 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
21 * GNU General Public License for more details.
23 * You should have received a copy of the GNU General Public License
24 * along with this program; if not, write to the Free Software
25 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
32 #ifdef HAVE_SYS_TYPES_H
33 # include <sys/types.h>
36 #ifdef HAVE_NETINET_IN_H
37 # include <netinet/in.h>
47 /* Include this for GVRP dissector */
48 #include "packet-gvrp.h"
50 /* Offsets of fields within a BPDU */
52 #define BPDU_IDENTIFIER 0
53 #define BPDU_VERSION_IDENTIFIER 2
56 #define BPDU_ROOT_IDENTIFIER 5
57 #define BPDU_ROOT_PATH_COST 13
58 #define BPDU_BRIDGE_IDENTIFIER 17
59 #define BPDU_PORT_IDENTIFIER 25
60 #define BPDU_MESSAGE_AGE 27
61 #define BPDU_MAX_AGE 29
62 #define BPDU_HELLO_TIME 31
63 #define BPDU_FORWARD_DELAY 33
65 static int proto_bpdu = -1;
66 static int hf_bpdu_proto_id = -1;
67 static int hf_bpdu_version_id = -1;
68 static int hf_bpdu_type = -1;
69 static int hf_bpdu_flags = -1;
70 static int hf_bpdu_root_mac = -1;
71 static int hf_bpdu_root_cost = -1;
72 static int hf_bpdu_bridge_mac = -1;
73 static int hf_bpdu_port_id = -1;
74 static int hf_bpdu_msg_age = -1;
75 static int hf_bpdu_max_age = -1;
76 static int hf_bpdu_hello_time = -1;
77 static int hf_bpdu_forward_delay = -1;
79 static gint ett_bpdu = -1;
82 dissect_bpdu(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree) {
83 guint16 protocol_identifier;
84 guint8 protocol_version_identifier;
87 guint16 root_identifier_bridge_priority;
88 guint8 *root_identifier_mac;
89 gchar *root_identifier_mac_str;
90 guint32 root_path_cost;
91 guint16 bridge_identifier_bridge_priority;
92 guint8 *bridge_identifier_mac;
93 gchar *bridge_identifier_mac_str;
94 guint16 port_identifier;
100 proto_tree *bpdu_tree;
103 CHECK_DISPLAY_AS_DATA(proto_bpdu, tvb, pinfo, tree);
105 /* GARP application frames require special interpretation of the
106 destination address field; otherwise, they will be mistaken as
108 Fortunately, they can be recognized by checking the first 6 octets
109 of the destination address, which are in the range from
110 01-80-C2-00-00-20 to 01-80-C2-00-00-2F.
112 Yes - we *do* need to check the destination address type;
113 on Linux cooked captures, there *is* no destination address,
115 if (pinfo->dl_dst.type == AT_ETHER &&
116 pinfo->dl_dst.data[0] == 0x01 && pinfo->dl_dst.data[1] == 0x80 &&
117 pinfo->dl_dst.data[2] == 0xC2 && pinfo->dl_dst.data[3] == 0x00 &&
118 pinfo->dl_dst.data[4] == 0x00 && ((pinfo->dl_dst.data[5] & 0x20) == 0x20)) {
120 protocol_identifier = tvb_get_ntohs(tvb, BPDU_IDENTIFIER);
122 switch (pinfo->dl_dst.data[5]) {
125 /* Future expansion for GMRP */
130 dissect_gvrp(tvb, pinfo, tree);
134 pinfo->current_proto = "GARP";
136 if (check_col(pinfo->fd, COL_PROTOCOL)) {
137 col_set_str(pinfo->fd, COL_PROTOCOL, "GARP");
138 /* Generic Attribute Registration Protocol */
141 if (check_col(pinfo->fd, COL_INFO)) {
142 col_add_fstr(pinfo->fd, COL_INFO,
143 "Unknown GARP application (0x%02X)",
144 pinfo->dl_dst.data[5]);
150 pinfo->current_proto = "STP";
152 bpdu_type = tvb_get_guint8(tvb, BPDU_TYPE);
153 flags = tvb_get_guint8(tvb, BPDU_FLAGS);
154 root_identifier_bridge_priority = tvb_get_ntohs(tvb, BPDU_ROOT_IDENTIFIER);
155 root_identifier_mac = tvb_get_ptr(tvb, BPDU_ROOT_IDENTIFIER + 2, 6);
156 root_identifier_mac_str = ether_to_str(root_identifier_mac);
157 root_path_cost = tvb_get_ntohl(tvb, BPDU_ROOT_PATH_COST);
158 port_identifier = tvb_get_ntohs(tvb, BPDU_PORT_IDENTIFIER);
160 if (check_col(pinfo->fd, COL_PROTOCOL)) {
161 col_set_str(pinfo->fd, COL_PROTOCOL, "STP"); /* Spanning Tree Protocol */
164 if (check_col(pinfo->fd, COL_INFO)) {
166 col_add_fstr(pinfo->fd, COL_INFO, "Conf. %sRoot = %d/%s Cost = %d Port = 0x%04x",
167 flags & 0x1 ? "TC + " : "",
168 root_identifier_bridge_priority, root_identifier_mac_str, root_path_cost,
170 else if (bpdu_type == 0x80)
171 col_add_fstr(pinfo->fd, COL_INFO, "Topology Change Notification");
175 protocol_identifier = tvb_get_ntohs(tvb, BPDU_IDENTIFIER);
176 protocol_version_identifier = tvb_get_guint8(tvb, BPDU_VERSION_IDENTIFIER);
178 ti = proto_tree_add_protocol_format(tree, proto_bpdu, tvb, 0, 35,
179 "Spanning Tree Protocol");
180 bpdu_tree = proto_item_add_subtree(ti, ett_bpdu);
181 proto_tree_add_uint_format(bpdu_tree, hf_bpdu_proto_id, tvb,
184 "Protocol Identifier: 0x%04x (%s)",
186 protocol_identifier == 0 ?
187 "Spanning Tree" : "Unknown Protocol");
189 proto_tree_add_uint(bpdu_tree, hf_bpdu_version_id, tvb,
190 BPDU_VERSION_IDENTIFIER, 1,
191 protocol_version_identifier);
192 if (protocol_version_identifier != 0)
193 proto_tree_add_text(bpdu_tree, tvb, BPDU_VERSION_IDENTIFIER, 1,
194 " (Warning: this version of Ethereal only knows about version = 0)");
195 proto_tree_add_uint_format(bpdu_tree, hf_bpdu_type, tvb,
198 "BPDU Type: 0x%02x (%s)",
200 bpdu_type == 0 ? "Configuration" :
201 bpdu_type == 0x80 ? "Topology Change Notification" : "Unknown");
203 if (bpdu_type != 0) {
204 dissect_data(tvb, BPDU_TYPE + 1, pinfo, tree);
208 bridge_identifier_bridge_priority = tvb_get_ntohs(tvb, BPDU_BRIDGE_IDENTIFIER);
209 bridge_identifier_mac = tvb_get_ptr(tvb, BPDU_BRIDGE_IDENTIFIER + 2, 6);
210 bridge_identifier_mac_str = ether_to_str(bridge_identifier_mac);
211 message_age = tvb_get_ntohs(tvb, BPDU_MESSAGE_AGE) / 256.0;
212 max_age = tvb_get_ntohs(tvb, BPDU_MAX_AGE) / 256.0;
213 hello_time = tvb_get_ntohs(tvb, BPDU_HELLO_TIME) / 256.0;
214 forward_delay = tvb_get_ntohs(tvb, BPDU_FORWARD_DELAY) / 256.0;
216 proto_tree_add_uint(bpdu_tree, hf_bpdu_flags, tvb,
217 BPDU_FLAGS, 1, flags);
219 proto_tree_add_text(bpdu_tree, tvb, BPDU_FLAGS, 1, " 1... .... Topology Change Acknowledgment");
221 proto_tree_add_text(bpdu_tree, tvb, BPDU_FLAGS, 1, " .... ...1 Topology Change");
223 proto_tree_add_ether_hidden(bpdu_tree, hf_bpdu_root_mac, tvb,
224 BPDU_ROOT_IDENTIFIER + 2, 6,
225 root_identifier_mac);
226 proto_tree_add_text(bpdu_tree, tvb,
227 BPDU_ROOT_IDENTIFIER, 8,
228 "Root Identifier: %d / %s",
229 root_identifier_bridge_priority,
230 root_identifier_mac_str);
231 proto_tree_add_uint(bpdu_tree, hf_bpdu_root_cost, tvb,
232 BPDU_ROOT_PATH_COST, 4,
234 proto_tree_add_text(bpdu_tree, tvb,
235 BPDU_BRIDGE_IDENTIFIER, 8,
236 "Bridge Identifier: %d / %s",
237 bridge_identifier_bridge_priority,
238 bridge_identifier_mac_str);
239 proto_tree_add_ether_hidden(bpdu_tree, hf_bpdu_bridge_mac, tvb,
240 BPDU_BRIDGE_IDENTIFIER + 2, 6,
241 bridge_identifier_mac);
242 proto_tree_add_uint(bpdu_tree, hf_bpdu_port_id, tvb,
243 BPDU_PORT_IDENTIFIER, 2,
245 proto_tree_add_double(bpdu_tree, hf_bpdu_msg_age, tvb,
248 proto_tree_add_double(bpdu_tree, hf_bpdu_max_age, tvb,
251 proto_tree_add_double(bpdu_tree, hf_bpdu_hello_time, tvb,
254 proto_tree_add_double(bpdu_tree, hf_bpdu_forward_delay, tvb,
255 BPDU_FORWARD_DELAY, 2,
261 proto_register_bpdu(void)
264 static hf_register_info hf[] = {
266 { "Protocol Identifier", "stp.protocol",
267 FT_UINT16, BASE_HEX, NULL, 0x0,
269 { &hf_bpdu_version_id,
270 { "Protocol Version Identifier", "stp.version",
271 FT_UINT8, BASE_DEC, NULL, 0x0,
274 { "BPDU type", "stp.type",
275 FT_UINT8, BASE_HEX, NULL, 0x0,
278 { "BPDU flags", "stp.flags",
279 FT_UINT8, BASE_HEX, NULL, 0x0,
282 { "Root Identifier", "stp.root.hw",
283 FT_ETHER, BASE_NONE, NULL, 0x0,
285 { &hf_bpdu_root_cost,
286 { "Root Path Cost", "stp.root.cost",
287 FT_UINT32, BASE_DEC, NULL, 0x0,
289 { &hf_bpdu_bridge_mac,
290 { "Bridge Identifier", "stp.bridge.hw",
291 FT_ETHER, BASE_NONE, NULL, 0x0,
294 { "Port identifier", "stp.port",
295 FT_UINT16, BASE_HEX, NULL, 0x0,
298 { "Message Age", "stp.msg_age",
299 FT_DOUBLE, BASE_NONE, NULL, 0x0,
302 { "Max Age", "stp.max_age",
303 FT_DOUBLE, BASE_NONE, NULL, 0x0,
305 { &hf_bpdu_hello_time,
306 { "Hello Time", "stp.hello",
307 FT_DOUBLE, BASE_NONE, NULL, 0x0,
309 { &hf_bpdu_forward_delay,
310 { "Forward Delay", "stp.forward",
311 FT_DOUBLE, BASE_NONE, NULL, 0x0,
314 static gint *ett[] = {
318 proto_bpdu = proto_register_protocol("Spanning Tree Protocol", "STP", "stp");
319 proto_register_field_array(proto_bpdu, hf, array_length(hf));
320 proto_register_subtree_array(ett, array_length(ett));
322 register_dissector("bpdu", dissect_bpdu);
326 proto_reg_handoff_bpdu(void)
328 dissector_add("llc.dsap", SAP_BPDU, dissect_bpdu);