GMRP dissector, from Markus Seehofer.
[obnox/wireshark/wip.git] / packet-bpdu.c
1 /* packet-bpdu.c
2  * Routines for BPDU (Spanning Tree Protocol) disassembly
3  *
4  * $Id: packet-bpdu.c,v 1.27 2001/07/23 18:21:30 guy Exp $
5  *
6  * Copyright 1999 Christophe Tronche <ch.tronche@computer.org>
7  * 
8  * Ethereal - Network traffic analyzer
9  * By Gerald Combs <gerald@ethereal.com>
10  * Copyright 1998 Gerald Combs
11  *
12  * 
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.
17  * 
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.
22  * 
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.
26  */
27
28 #ifdef HAVE_CONFIG_H
29 # include "config.h"
30 #endif
31
32 #ifdef HAVE_SYS_TYPES_H
33 # include <sys/types.h>
34 #endif
35
36 #ifdef HAVE_NETINET_IN_H
37 # include <netinet/in.h>
38 #endif
39
40 #include <stdio.h>
41 #include <string.h>
42 #include <glib.h>
43 #include "packet.h"
44 #include "llcsaps.h"
45 #include "ppptypes.h"
46 #include "resolv.h"
47
48 /* Offsets of fields within a BPDU */
49
50 #define BPDU_IDENTIFIER          0
51 #define BPDU_VERSION_IDENTIFIER  2
52 #define BPDU_TYPE                3
53 #define BPDU_FLAGS               4
54 #define BPDU_ROOT_IDENTIFIER     5
55 #define BPDU_ROOT_PATH_COST     13
56 #define BPDU_BRIDGE_IDENTIFIER  17
57 #define BPDU_PORT_IDENTIFIER    25
58 #define BPDU_MESSAGE_AGE        27
59 #define BPDU_MAX_AGE            29
60 #define BPDU_HELLO_TIME         31
61 #define BPDU_FORWARD_DELAY      33
62
63 static int proto_bpdu = -1;
64 static int hf_bpdu_proto_id = -1;
65 static int hf_bpdu_version_id = -1;
66 static int hf_bpdu_type = -1;
67 static int hf_bpdu_flags = -1;
68 static int hf_bpdu_root_mac = -1;
69 static int hf_bpdu_root_cost = -1;
70 static int hf_bpdu_bridge_mac = -1;
71 static int hf_bpdu_port_id = -1;
72 static int hf_bpdu_msg_age = -1;
73 static int hf_bpdu_max_age = -1;
74 static int hf_bpdu_hello_time = -1;
75 static int hf_bpdu_forward_delay = -1;
76
77 static gint ett_bpdu = -1;
78
79 static dissector_handle_t gvrp_handle;
80 static dissector_handle_t gmrp_handle;
81
82 static void
83 dissect_bpdu(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree) {
84       guint16 protocol_identifier;
85       guint8  protocol_version_identifier;
86       guint8  bpdu_type;
87       guint8  flags;
88       guint16 root_identifier_bridge_priority;
89       const guint8  *root_identifier_mac;
90       gchar   *root_identifier_mac_str;
91       guint32 root_path_cost;
92       guint16 bridge_identifier_bridge_priority;
93       const guint8  *bridge_identifier_mac;
94       gchar   *bridge_identifier_mac_str;
95       guint16 port_identifier;
96       double message_age;
97       double max_age;
98       double hello_time;
99       double forward_delay;
100       
101       proto_tree *bpdu_tree;
102       proto_item *ti;
103
104       /* GARP application frames require special interpretation of the
105          destination address field; otherwise, they will be mistaken as
106          BPDU frames.  
107          Fortunately, they can be recognized by checking the first 6 octets
108          of the destination address, which are in the range from
109          01-80-C2-00-00-20 to 01-80-C2-00-00-2F.
110
111          Yes - we *do* need to check the destination address type;
112          on Linux cooked captures, there *is* no destination address,
113          so it's AT_NONE. */
114       if (pinfo->dl_dst.type == AT_ETHER &&
115           pinfo->dl_dst.data[0] == 0x01 && pinfo->dl_dst.data[1] == 0x80 &&
116           pinfo->dl_dst.data[2] == 0xC2 && pinfo->dl_dst.data[3] == 0x00 &&
117           pinfo->dl_dst.data[4] == 0x00 && ((pinfo->dl_dst.data[5] & 0x20) == 0x20)) {
118
119             protocol_identifier = tvb_get_ntohs(tvb, BPDU_IDENTIFIER);
120
121             switch (pinfo->dl_dst.data[5]) {
122
123             case 0x20:
124                    /* for GMRP */
125                   call_dissector(gmrp_handle, tvb, pinfo, tree);
126                   return;
127
128             case 0x21:
129                   /* for GVRP */
130                   call_dissector(gvrp_handle, tvb, pinfo, tree);
131                   return;
132             }
133
134             pinfo->current_proto = "GARP";
135
136             if (check_col(pinfo->fd, COL_PROTOCOL)) {
137                     col_set_str(pinfo->fd, COL_PROTOCOL, "GARP");
138                     /* Generic Attribute Registration Protocol */
139             }
140
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]);
145             }
146
147             return;
148       }
149
150       if (check_col(pinfo->fd, COL_PROTOCOL)) {
151             col_set_str(pinfo->fd, COL_PROTOCOL, "STP"); /* Spanning Tree Protocol */
152       }
153       if (check_col(pinfo->fd, COL_INFO)) {
154             col_clear(pinfo->fd, COL_INFO);
155       }
156
157       bpdu_type = tvb_get_guint8(tvb, BPDU_TYPE);
158       if (bpdu_type == 0) {
159             flags = tvb_get_guint8(tvb, BPDU_FLAGS);
160             root_identifier_bridge_priority = tvb_get_ntohs(tvb,
161                 BPDU_ROOT_IDENTIFIER);
162             root_identifier_mac = tvb_get_ptr(tvb, BPDU_ROOT_IDENTIFIER + 2, 6);
163             root_identifier_mac_str = ether_to_str(root_identifier_mac);
164             root_path_cost = tvb_get_ntohl(tvb, BPDU_ROOT_PATH_COST);
165             port_identifier = tvb_get_ntohs(tvb, BPDU_PORT_IDENTIFIER);
166       } else {
167             /* Squelch GCC complaints. */
168             flags = 0;
169             root_identifier_bridge_priority = 0;
170             root_identifier_mac = NULL;
171             root_identifier_mac_str = NULL;
172             root_path_cost = 0;
173             port_identifier = 0;
174       }
175
176       if (check_col(pinfo->fd, COL_INFO)) {
177             if (bpdu_type == 0)
178                   col_add_fstr(pinfo->fd, COL_INFO, "Conf. %sRoot = %d/%s  Cost = %d  Port = 0x%04x", 
179                                flags & 0x1 ? "TC + " : "",
180                                root_identifier_bridge_priority, root_identifier_mac_str, root_path_cost,
181                                port_identifier);
182             else if (bpdu_type == 0x80)
183                   col_add_fstr(pinfo->fd, COL_INFO, "Topology Change Notification");
184       }
185
186       if (tree) {
187             ti = proto_tree_add_protocol_format(tree, proto_bpdu, tvb, 0, 35,
188                                 "Spanning Tree Protocol");
189             bpdu_tree = proto_item_add_subtree(ti, ett_bpdu);
190
191             protocol_identifier = tvb_get_ntohs(tvb, BPDU_IDENTIFIER);
192             proto_tree_add_uint_format(bpdu_tree, hf_bpdu_proto_id, tvb,
193                                        BPDU_IDENTIFIER, 2, 
194                                        protocol_identifier,
195                                        "Protocol Identifier: 0x%04x (%s)", 
196                                        protocol_identifier,
197                                        protocol_identifier == 0 ? 
198                                        "Spanning Tree" : "Unknown Protocol");
199
200             protocol_version_identifier = tvb_get_guint8(tvb, BPDU_VERSION_IDENTIFIER);
201             proto_tree_add_uint(bpdu_tree, hf_bpdu_version_id, tvb, 
202                                 BPDU_VERSION_IDENTIFIER, 1, 
203                                 protocol_version_identifier);
204             if (protocol_version_identifier != 0)
205                   proto_tree_add_text(bpdu_tree, tvb, BPDU_VERSION_IDENTIFIER, 1,
206                   "   (Warning: this version of Ethereal only knows about version = 0)");
207             proto_tree_add_uint_format(bpdu_tree, hf_bpdu_type, tvb,
208                                        BPDU_TYPE, 1, 
209                                        bpdu_type,
210                                        "BPDU Type: 0x%02x (%s)", 
211                                        bpdu_type,
212                                        bpdu_type == 0 ? "Configuration" :
213                                        bpdu_type == 0x80 ? "Topology Change Notification" : "Unknown");
214
215             if (bpdu_type != 0) {
216               dissect_data(tvb, BPDU_TYPE + 1, pinfo, tree);
217               return;
218             }
219
220             bridge_identifier_bridge_priority = tvb_get_ntohs(tvb, BPDU_BRIDGE_IDENTIFIER);
221             bridge_identifier_mac = tvb_get_ptr(tvb, BPDU_BRIDGE_IDENTIFIER + 2, 6);
222             bridge_identifier_mac_str = ether_to_str(bridge_identifier_mac);
223             message_age = tvb_get_ntohs(tvb, BPDU_MESSAGE_AGE) / 256.0;
224             max_age = tvb_get_ntohs(tvb, BPDU_MAX_AGE) / 256.0;
225             hello_time = tvb_get_ntohs(tvb, BPDU_HELLO_TIME) / 256.0;
226             forward_delay = tvb_get_ntohs(tvb, BPDU_FORWARD_DELAY) / 256.0;
227
228             proto_tree_add_uint(bpdu_tree, hf_bpdu_flags, tvb, 
229                                 BPDU_FLAGS, 1, flags);
230             if (flags & 0x80)
231                   proto_tree_add_text(bpdu_tree, tvb, BPDU_FLAGS, 1, "   1... ....  Topology Change Acknowledgment");
232             if (flags & 0x01)
233                   proto_tree_add_text(bpdu_tree, tvb, BPDU_FLAGS, 1, "   .... ...1  Topology Change");
234
235             proto_tree_add_ether_hidden(bpdu_tree, hf_bpdu_root_mac, tvb,
236                                        BPDU_ROOT_IDENTIFIER + 2, 6,
237                                        root_identifier_mac);
238             proto_tree_add_text(bpdu_tree, tvb, 
239                                 BPDU_ROOT_IDENTIFIER, 8, 
240                                 "Root Identifier: %d / %s", 
241                                 root_identifier_bridge_priority, 
242                                 root_identifier_mac_str);
243             proto_tree_add_uint(bpdu_tree, hf_bpdu_root_cost, tvb, 
244                                 BPDU_ROOT_PATH_COST, 4, 
245                                 root_path_cost);
246             proto_tree_add_text(bpdu_tree, tvb, 
247                                 BPDU_BRIDGE_IDENTIFIER, 8, 
248                                 "Bridge Identifier: %d / %s", 
249                                 bridge_identifier_bridge_priority, 
250                                 bridge_identifier_mac_str);
251             proto_tree_add_ether_hidden(bpdu_tree, hf_bpdu_bridge_mac, tvb,
252                                        BPDU_BRIDGE_IDENTIFIER + 2, 6,
253                                        bridge_identifier_mac);
254             proto_tree_add_uint(bpdu_tree, hf_bpdu_port_id, tvb,
255                                 BPDU_PORT_IDENTIFIER, 2, 
256                                 port_identifier);
257             proto_tree_add_double(bpdu_tree, hf_bpdu_msg_age, tvb,
258                                 BPDU_MESSAGE_AGE, 2, 
259                                 message_age);
260             proto_tree_add_double(bpdu_tree, hf_bpdu_max_age, tvb,
261                                 BPDU_MAX_AGE, 2, 
262                                 max_age);
263             proto_tree_add_double(bpdu_tree, hf_bpdu_hello_time, tvb,
264                                 BPDU_HELLO_TIME, 2, 
265                                 hello_time);
266             proto_tree_add_double(bpdu_tree, hf_bpdu_forward_delay, tvb,
267                                 BPDU_FORWARD_DELAY, 2, 
268                                 forward_delay);
269       }
270 }
271
272 void
273 proto_register_bpdu(void)
274 {
275
276   static hf_register_info hf[] = {
277     { &hf_bpdu_proto_id,
278       { "Protocol Identifier",          "stp.protocol",
279         FT_UINT16,      BASE_HEX,       NULL,   0x0,
280         "", HFILL }},
281     { &hf_bpdu_version_id,
282       { "Protocol Version Identifier",  "stp.version",
283         FT_UINT8,       BASE_DEC,       NULL,   0x0,
284         "", HFILL }},
285     { &hf_bpdu_type,
286       { "BPDU type",                    "stp.type",
287         FT_UINT8,       BASE_HEX,       NULL,   0x0,
288         "", HFILL }},
289     { &hf_bpdu_flags,
290       { "BPDU flags",                   "stp.flags",
291         FT_UINT8,       BASE_HEX,       NULL,   0x0,
292         "", HFILL }},
293     { &hf_bpdu_root_mac,
294       { "Root Identifier",              "stp.root.hw",
295         FT_ETHER,       BASE_NONE,      NULL,   0x0,
296         "", HFILL }},
297     { &hf_bpdu_root_cost,
298       { "Root Path Cost",               "stp.root.cost",
299         FT_UINT32,      BASE_DEC,       NULL,   0x0,
300         "", HFILL }},
301     { &hf_bpdu_bridge_mac,
302       { "Bridge Identifier",            "stp.bridge.hw",
303         FT_ETHER,       BASE_NONE,      NULL,   0x0,
304         "", HFILL }},
305     { &hf_bpdu_port_id,
306       { "Port identifier",              "stp.port",
307         FT_UINT16,      BASE_HEX,       NULL,   0x0,
308         "", HFILL }},
309     { &hf_bpdu_msg_age,
310       { "Message Age",                  "stp.msg_age",
311         FT_DOUBLE,      BASE_NONE,      NULL,   0x0,
312         "", HFILL }},
313     { &hf_bpdu_max_age,
314       { "Max Age",                      "stp.max_age",
315         FT_DOUBLE,      BASE_NONE,      NULL,   0x0,
316         "", HFILL }},
317     { &hf_bpdu_hello_time,
318       { "Hello Time",                   "stp.hello",
319         FT_DOUBLE,      BASE_NONE,      NULL,   0x0,
320         "", HFILL }},
321     { &hf_bpdu_forward_delay,
322       { "Forward Delay",                "stp.forward",
323         FT_DOUBLE,      BASE_NONE,      NULL,   0x0,
324         "", HFILL }},
325   };
326   static gint *ett[] = {
327     &ett_bpdu,
328   };
329
330   proto_bpdu = proto_register_protocol("Spanning Tree Protocol", "STP", "stp");
331   proto_register_field_array(proto_bpdu, hf, array_length(hf));
332   proto_register_subtree_array(ett, array_length(ett));
333
334   register_dissector("bpdu", dissect_bpdu, proto_bpdu);
335 }
336
337 void
338 proto_reg_handoff_bpdu(void)
339 {
340   /*
341    * Get handle for the GVRP dissector.
342    */
343   gvrp_handle = find_dissector("gvrp");
344   
345   /*
346    * Get handle for the GMRP dissector.
347    */
348   gmrp_handle = find_dissector("gmrp");
349
350   dissector_add("llc.dsap", SAP_BPDU, dissect_bpdu, proto_bpdu);
351   dissector_add("ppp.protocol", PPP_BPDU, dissect_bpdu, proto_bpdu);
352 }