xref: /dflybsd-src/sys/net/bridge/bridgestp.c (revision 127a3eb4035f914ee311e89500f4d77abda51b3f)
1 /*
2  * Copyright (c) 2000 Jason L. Wright (jason@thought.net)
3  * All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer.
10  * 2. Redistributions in binary form must reproduce the above copyright
11  *    notice, this list of conditions and the following disclaimer in the
12  *    documentation and/or other materials provided with the distribution.
13  * 3. All advertising materials mentioning features or use of this software
14  *    must display the following acknowledgement:
15  *      This product includes software developed by Jason L. Wright
16  * 4. The name of the author may not be used to endorse or promote products
17  *    derived from this software without specific prior written permission.
18  *
19  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
20  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
21  * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
22  * DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT,
23  * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
24  * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
25  * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
27  * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
28  * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
29  * POSSIBILITY OF SUCH DAMAGE.
30  *
31  * $OpenBSD: bridgestp.c,v 1.5 2001/03/22 03:48:29 jason Exp $
32  * $NetBSD: bridgestp.c,v 1.5 2003/11/28 08:56:48 keihan Exp $
33  * $FreeBSD: src/sys/net/bridgestp.c,v 1.7 2005/10/11 02:58:32 thompsa Exp $
34  */
35 
36 /*
37  * Implementation of the spanning tree protocol as defined in
38  * ISO/IEC Final DIS 15802-3 (IEEE P802.1D/D17), May 25, 1998.
39  * (In English: IEEE 802.1D, Draft 17, 1998)
40  */
41 
42 #include <sys/param.h>
43 #include <sys/systm.h>
44 #include <sys/mbuf.h>
45 #include <sys/socket.h>
46 #include <sys/sockio.h>
47 #include <sys/kernel.h>
48 #include <sys/callout.h>
49 #include <sys/proc.h>
50 #include <sys/lock.h>
51 #include <sys/thread.h>
52 #include <sys/thread2.h>
53 #include <sys/msgport2.h>
54 
55 #include <net/if.h>
56 #include <net/if_dl.h>
57 #include <net/if_types.h>
58 #include <net/if_llc.h>
59 #include <net/if_media.h>
60 
61 #include <netinet/in.h>
62 #include <netinet/in_systm.h>
63 #include <netinet/in_var.h>
64 #include <netinet/if_ether.h>
65 #include <net/bridge/if_bridgevar.h>
66 
67 /* BPDU message types */
68 #define	BSTP_MSGTYPE_CFG	0x00		/* Configuration */
69 #define	BSTP_MSGTYPE_TCN	0x80		/* Topology chg notification */
70 
71 /* BPDU flags */
72 #define	BSTP_FLAG_TC		0x01		/* Topology change */
73 #define	BSTP_FLAG_TCA		0x80		/* Topology change ack */
74 
75 #define	BSTP_MESSAGE_AGE_INCR	(1 * 256)	/* in 256ths of a second */
76 #define	BSTP_TICK_VAL		(1 * 256)	/* in 256ths of a second */
77 
78 /*
79  * Because BPDU's do not make nicely aligned structures, two different
80  * declarations are used: bstp_?bpdu (wire representation, packed) and
81  * bstp_*_unit (internal, nicely aligned version).
82  */
83 
84 /* configuration bridge protocol data unit */
85 struct bstp_cbpdu {
86 	uint8_t		cbu_dsap;		/* LLC: destination sap */
87 	uint8_t		cbu_ssap;		/* LLC: source sap */
88 	uint8_t		cbu_ctl;		/* LLC: control */
89 	uint16_t	cbu_protoid;		/* protocol id */
90 	uint8_t		cbu_protover;		/* protocol version */
91 	uint8_t		cbu_bpdutype;		/* message type */
92 	uint8_t		cbu_flags;		/* flags (below) */
93 
94 	/* root id */
95 	uint16_t	cbu_rootpri;		/* root priority */
96 	uint8_t	cbu_rootaddr[6];	/* root address */
97 
98 	uint32_t	cbu_rootpathcost;	/* root path cost */
99 
100 	/* bridge id */
101 	uint16_t	cbu_bridgepri;		/* bridge priority */
102 	uint8_t		cbu_bridgeaddr[6];	/* bridge address */
103 
104 	uint16_t	cbu_portid;		/* port id */
105 	uint16_t	cbu_messageage;		/* current message age */
106 	uint16_t	cbu_maxage;		/* maximum age */
107 	uint16_t	cbu_hellotime;		/* hello time */
108 	uint16_t	cbu_forwarddelay;	/* forwarding delay */
109 } __attribute__((__packed__));
110 
111 /* topology change notification bridge protocol data unit */
112 struct bstp_tbpdu {
113 	uint8_t		tbu_dsap;		/* LLC: destination sap */
114 	uint8_t		tbu_ssap;		/* LLC: source sap */
115 	uint8_t		tbu_ctl;		/* LLC: control */
116 	uint16_t	tbu_protoid;		/* protocol id */
117 	uint8_t		tbu_protover;		/* protocol version */
118 	uint8_t		tbu_bpdutype;		/* message type */
119 } __attribute__((__packed__));
120 
121 const uint8_t bstp_etheraddr[] = { 0x01, 0x80, 0xc2, 0x00, 0x00, 0x00 };
122 
123 static void	bstp_initialize_port(struct bridge_softc *,
124 		    struct bridge_iflist *);
125 static void	bstp_ifupdstatus(struct bridge_softc *, struct bridge_iflist *);
126 static void	bstp_enable_port(struct bridge_softc *, struct bridge_iflist *);
127 static void	bstp_disable_port(struct bridge_softc *,
128 		    struct bridge_iflist *);
129 #ifdef notused
130 static void	bstp_enable_change_detection(struct bridge_iflist *);
131 static void	bstp_disable_change_detection(struct bridge_iflist *);
132 #endif /* notused */
133 static int	bstp_root_bridge(struct bridge_softc *sc);
134 static void	bstp_transmit_config(struct bridge_softc *,
135 		    struct bridge_iflist *);
136 static void	bstp_transmit_tcn(struct bridge_softc *);
137 static void	bstp_received_config_bpdu(struct bridge_softc *,
138 		    struct bridge_iflist *, struct bstp_config_unit *);
139 static void	bstp_received_tcn_bpdu(struct bridge_softc *,
140 		    struct bridge_iflist *, struct bstp_tcn_unit *);
141 static void	bstp_record_config_information(struct bridge_softc *,
142 		    struct bridge_iflist *, struct bstp_config_unit *);
143 static void	bstp_record_config_timeout_values(struct bridge_softc *,
144 		    struct bstp_config_unit *);
145 static void	bstp_config_bpdu_generation(struct bridge_softc *);
146 static void	bstp_send_config_bpdu(struct bridge_softc *,
147 		    struct bridge_iflist *, struct bstp_config_unit *);
148 static void	bstp_configuration_update(struct bridge_softc *);
149 static void	bstp_port_state_selection(struct bridge_softc *);
150 static void	bstp_clear_peer_info(struct bridge_softc *,
151 		    struct bridge_iflist *);
152 static void	bstp_make_forwarding(struct bridge_softc *,
153 		    struct bridge_iflist *);
154 static void	bstp_make_blocking(struct bridge_softc *,
155 		    struct bridge_iflist *);
156 static void	bstp_make_l1blocking(struct bridge_softc *sc,
157 		    struct bridge_iflist *bif);
158 static void	bstp_adjust_bonded_states(struct bridge_softc *sc,
159 		    struct bridge_iflist *obif);
160 static void	bstp_set_port_state(struct bridge_iflist *, uint8_t);
161 #ifdef notused
162 static void	bstp_set_bridge_priority(struct bridge_softc *, uint64_t);
163 static void	bstp_set_port_priority(struct bridge_softc *,
164 		    struct bridge_iflist *, uint16_t);
165 static void	bstp_set_path_cost(struct bridge_softc *,
166 		    struct bridge_iflist *, uint32_t);
167 #endif /* notused */
168 static void	bstp_topology_change_detection(struct bridge_softc *);
169 static void	bstp_topology_change_acknowledged(struct bridge_softc *);
170 static void	bstp_acknowledge_topology_change(struct bridge_softc *,
171 		    struct bridge_iflist *);
172 
173 static void	bstp_tick(void *);
174 static void	bstp_timer_start(struct bridge_timer *, uint16_t);
175 static void	bstp_timer_stop(struct bridge_timer *);
176 static int	bstp_timer_expired(struct bridge_timer *, uint16_t);
177 
178 static void	bstp_hold_timer_expiry(struct bridge_softc *,
179 		    struct bridge_iflist *);
180 static void	bstp_message_age_timer_expiry(struct bridge_softc *,
181 		    struct bridge_iflist *);
182 static void	bstp_forward_delay_timer_expiry(struct bridge_softc *,
183 		    struct bridge_iflist *);
184 static void	bstp_topology_change_timer_expiry(struct bridge_softc *);
185 static void	bstp_tcn_timer_expiry(struct bridge_softc *);
186 static void	bstp_hello_timer_expiry(struct bridge_softc *);
187 static int	bstp_addr_cmp(const uint8_t *, const uint8_t *);
188 
189 /*
190  * When transmitting a config we tack on our path cost to
191  * our aggregated path-to-root cost.
192  */
193 static void
194 bstp_transmit_config(struct bridge_softc *sc, struct bridge_iflist *bif)
195 {
196 	if (bif->bif_hold_timer.active) {
197 		bif->bif_config_pending = 1;
198 		return;
199 	}
200 
201 	bif->bif_config_bpdu.cu_message_type = BSTP_MSGTYPE_CFG;
202 	bif->bif_config_bpdu.cu_rootid = sc->sc_designated_root;
203 	bif->bif_config_bpdu.cu_root_path_cost = sc->sc_designated_cost +
204 						 bif->bif_path_cost;
205 	bif->bif_config_bpdu.cu_bridge_id = sc->sc_bridge_id;
206 	bif->bif_config_bpdu.cu_port_id = bif->bif_port_id;
207 
208 	if (bstp_root_bridge(sc)) {
209 		bif->bif_config_bpdu.cu_message_age = 0;
210 	} else if (sc->sc_root_port) {
211 		bif->bif_config_bpdu.cu_message_age =
212 			sc->sc_root_port->bif_message_age_timer.value +
213 			BSTP_MESSAGE_AGE_INCR;
214 	} else {
215 		bif->bif_config_bpdu.cu_message_age = BSTP_MESSAGE_AGE_INCR;
216 	}
217 
218 	bif->bif_config_bpdu.cu_max_age = sc->sc_max_age;
219 	bif->bif_config_bpdu.cu_hello_time = sc->sc_hello_time;
220 	bif->bif_config_bpdu.cu_forward_delay = sc->sc_forward_delay;
221 	bif->bif_config_bpdu.cu_topology_change_acknowledgment
222 	    = bif->bif_topology_change_acknowledge;
223 	bif->bif_config_bpdu.cu_topology_change = sc->sc_topology_change;
224 
225 	if (bif->bif_config_bpdu.cu_message_age < sc->sc_max_age ||
226 	    (sc->sc_ifp->if_flags & IFF_LINK1)) {
227 		bif->bif_topology_change_acknowledge = 0;
228 		bif->bif_config_pending = 0;
229 		bstp_send_config_bpdu(sc, bif, &bif->bif_config_bpdu);
230 		bstp_timer_start(&bif->bif_hold_timer, 0);
231 	}
232 }
233 
234 static void
235 bstp_send_config_bpdu(struct bridge_softc *sc, struct bridge_iflist *bif,
236 		      struct bstp_config_unit *cu)
237 {
238 	struct ifnet *ifp;
239 	struct mbuf *m;
240 	struct ether_header *eh;
241 	struct bstp_cbpdu bpdu;
242 
243 	ifp = bif->bif_ifp;
244 
245 	if ((ifp->if_flags & IFF_RUNNING) == 0)
246 		return;
247 
248 	MGETHDR(m, MB_DONTWAIT, MT_DATA);
249 	if (m == NULL)
250 		return;
251 
252 	eh = mtod(m, struct ether_header *);
253 
254 	m->m_pkthdr.rcvif = ifp;
255 	m->m_pkthdr.len = sizeof(*eh) + sizeof(bpdu);
256 	m->m_len = m->m_pkthdr.len;
257 
258 	bpdu.cbu_ssap = bpdu.cbu_dsap = LLC_8021D_LSAP;
259 	bpdu.cbu_ctl = LLC_UI;
260 	bpdu.cbu_protoid = htons(0);
261 	bpdu.cbu_protover = 0;
262 	bpdu.cbu_bpdutype = cu->cu_message_type;
263 	bpdu.cbu_flags = (cu->cu_topology_change ? BSTP_FLAG_TC : 0) |
264 	    (cu->cu_topology_change_acknowledgment ? BSTP_FLAG_TCA : 0);
265 
266 	bpdu.cbu_rootpri = htons(cu->cu_rootid >> 48);
267 	bpdu.cbu_rootaddr[0] = cu->cu_rootid >> 40;
268 	bpdu.cbu_rootaddr[1] = cu->cu_rootid >> 32;
269 	bpdu.cbu_rootaddr[2] = cu->cu_rootid >> 24;
270 	bpdu.cbu_rootaddr[3] = cu->cu_rootid >> 16;
271 	bpdu.cbu_rootaddr[4] = cu->cu_rootid >> 8;
272 	bpdu.cbu_rootaddr[5] = cu->cu_rootid >> 0;
273 
274 	bpdu.cbu_rootpathcost = htonl(cu->cu_root_path_cost);
275 
276 	bpdu.cbu_bridgepri = htons(cu->cu_bridge_id >> 48);
277 	bpdu.cbu_bridgeaddr[0] = cu->cu_bridge_id >> 40;
278 	bpdu.cbu_bridgeaddr[1] = cu->cu_bridge_id >> 32;
279 	bpdu.cbu_bridgeaddr[2] = cu->cu_bridge_id >> 24;
280 	bpdu.cbu_bridgeaddr[3] = cu->cu_bridge_id >> 16;
281 	bpdu.cbu_bridgeaddr[4] = cu->cu_bridge_id >> 8;
282 	bpdu.cbu_bridgeaddr[5] = cu->cu_bridge_id >> 0;
283 
284 	bpdu.cbu_portid = htons(cu->cu_port_id);
285 	bpdu.cbu_messageage = htons(cu->cu_message_age);
286 	bpdu.cbu_maxage = htons(cu->cu_max_age);
287 	bpdu.cbu_hellotime = htons(cu->cu_hello_time);
288 	bpdu.cbu_forwarddelay = htons(cu->cu_forward_delay);
289 
290 	/*
291 	 * Packets sent from the bridge always use the bridge MAC
292 	 * as the source.
293 	 */
294 	memcpy(eh->ether_shost, IF_LLADDR(sc->sc_ifp), ETHER_ADDR_LEN);
295 	memcpy(eh->ether_dhost, bstp_etheraddr, ETHER_ADDR_LEN);
296 	eh->ether_type = htons(sizeof(bpdu));
297 
298 	memcpy(mtod(m, caddr_t) + sizeof(*eh), &bpdu, sizeof(bpdu));
299 
300 	bridge_enqueue(ifp, m);
301 }
302 
303 static int
304 bstp_root_bridge(struct bridge_softc *sc)
305 {
306 	return (sc->sc_designated_root == sc->sc_bridge_id);
307 }
308 
309 /*
310  * Returns TRUE if the recorded information from our peer has a shorter
311  * graph distance than our current best.
312  */
313 int
314 bstp_supersedes_port_info(struct bridge_softc *sc, struct bridge_iflist *bif)
315 {
316 	if (bif->bif_peer_root < sc->sc_designated_root)
317 		return (1);
318 	if (bif->bif_peer_root > sc->sc_designated_root)
319 		return (0);
320 
321 	/*
322 	 * Both bif_peer_cost and sc_designated_cost have NOT added in
323 	 * bif->bif_path_cost, so we can optimize it out.
324 	 */
325 	if (bif->bif_peer_cost < sc->sc_designated_cost)
326 		return (1);
327 	if (bif->bif_peer_cost > sc->sc_designated_cost)
328 		return (0);
329 
330 	if (bif->bif_peer_bridge < sc->sc_designated_bridge)
331 		return (1);
332 	if (bif->bif_peer_bridge > sc->sc_designated_bridge)
333 		return (0);
334 
335 	/* bridge_id or bridge+port collision w/peer returns TRUE */
336 	if (bif->bif_peer_bridge != sc->sc_bridge_id)
337 		return (1);
338 	if (bif->bif_peer_port <= sc->sc_designated_port)
339 		return (1);
340 	return (0);
341 }
342 
343 /*
344  * The shorter graph distance represented by cu (most of which is also
345  * already stored in our bif_peer_* fields) becomes the designated info.
346  *
347  * NOTE: sc_designated_cost does not include bif_path_cost, it is added
348  *	 in later on a port-by-port basis as needed.
349  */
350 static void
351 bstp_record_config_information(struct bridge_softc *sc,
352 			       struct bridge_iflist *bif,
353 			       struct bstp_config_unit *cu)
354 {
355 	sc->sc_designated_root = bif->bif_peer_root;
356 	sc->sc_designated_cost = bif->bif_peer_cost;
357 	sc->sc_designated_bridge = bif->bif_peer_bridge;
358 	sc->sc_designated_port = bif->bif_peer_port;
359 	bstp_timer_start(&bif->bif_message_age_timer, cu->cu_message_age);
360 }
361 
362 static void
363 bstp_record_config_timeout_values(struct bridge_softc *sc,
364 				  struct bstp_config_unit *config)
365 {
366 	sc->sc_max_age = config->cu_max_age;
367 	sc->sc_hello_time = config->cu_hello_time;
368 	sc->sc_forward_delay = config->cu_forward_delay;
369 	sc->sc_topology_change = config->cu_topology_change;
370 }
371 
372 static void
373 bstp_config_bpdu_generation(struct bridge_softc *sc)
374 {
375 	struct bridge_iflist *bif, *nbif;
376 
377 	TAILQ_FOREACH_MUTABLE(bif, &sc->sc_iflists[mycpuid], bif_next, nbif) {
378 		if ((bif->bif_flags & IFBIF_STP) == 0)
379 			continue;
380 		if (bif->bif_state != BSTP_IFSTATE_DISABLED &&
381 		    ((sc->sc_ifp->if_flags & IFF_LINK1) ||
382 		     (bif->bif_flags & IFBIF_DESIGNATED))) {
383 			bstp_transmit_config(sc, bif);
384 		}
385 
386 		if (nbif != NULL && !nbif->bif_onlist) {
387 			KKASSERT(bif->bif_onlist);
388 			nbif = TAILQ_NEXT(bif, bif_next);
389 		}
390 	}
391 }
392 
393 static void
394 bstp_transmit_tcn(struct bridge_softc *sc)
395 {
396 	struct bstp_tbpdu bpdu;
397 	struct ifnet *ifp;
398 	struct ether_header *eh;
399 	struct mbuf *m;
400 
401 	if (sc->sc_root_port == NULL)	/* all iterfaces disabled */
402 		return;
403 
404 	ifp = sc->sc_root_port->bif_ifp;
405 	if ((ifp->if_flags & IFF_RUNNING) == 0)
406 		return;
407 
408 	MGETHDR(m, MB_DONTWAIT, MT_DATA);
409 	if (m == NULL)
410 		return;
411 
412 	m->m_pkthdr.rcvif = ifp;
413 	m->m_pkthdr.len = sizeof(*eh) + sizeof(bpdu);
414 	m->m_len = m->m_pkthdr.len;
415 
416 	eh = mtod(m, struct ether_header *);
417 
418 	/*
419 	 * Packets sent from the bridge always use the bridge MAC
420 	 * as the source.
421 	 */
422 	memcpy(eh->ether_shost, IF_LLADDR(sc->sc_ifp), ETHER_ADDR_LEN);
423 	memcpy(eh->ether_dhost, bstp_etheraddr, ETHER_ADDR_LEN);
424 	eh->ether_type = htons(sizeof(bpdu));
425 
426 	bpdu.tbu_ssap = bpdu.tbu_dsap = LLC_8021D_LSAP;
427 	bpdu.tbu_ctl = LLC_UI;
428 	bpdu.tbu_protoid = 0;
429 	bpdu.tbu_protover = 0;
430 	bpdu.tbu_bpdutype = BSTP_MSGTYPE_TCN;
431 
432 	memcpy(mtod(m, caddr_t) + sizeof(*eh), &bpdu, sizeof(bpdu));
433 
434 	bridge_enqueue(ifp, m);
435 }
436 
437 /*
438  * Recalculate sc->sc_designated* and sc->sc_root_port (if our bridge
439  * is calculated to be the root bridge).  We do this by initializing
440  * the designated variables to point at us and then scan our peers.
441  * Any uninitialized peers will have a max-value root.
442  *
443  * Clear IFBIF_DESIGNATED on any ports which no longer match the criteria
444  * required to be a designated port.  Only aged out ports and the root
445  * port can be designated.
446  *
447  * If we win we do a second scan to determine which port on our bridge
448  * is the best.
449  */
450 static void
451 bstp_configuration_update(struct bridge_softc *sc)
452 {
453 	uint64_t	designated_root = sc->sc_bridge_id;
454 	uint64_t	designated_bridge = sc->sc_bridge_id;
455 	uint32_t	designated_cost = 0xFFFFFFFFU;
456 	uint16_t	designated_port = 65535;
457 	struct bridge_iflist *root_port = NULL;
458 	struct bridge_iflist *bif;
459 
460 	/*
461 	 * Resolve information from our peers.  Aged peers will have
462 	 * a maxed bif_peer_root and not come under consideration.
463 	 */
464 	TAILQ_FOREACH(bif, &sc->sc_iflists[mycpuid], bif_next) {
465 		if ((bif->bif_flags & IFBIF_STP) == 0)
466 			continue;
467 		if (bif->bif_state == BSTP_IFSTATE_DISABLED ||
468 		    bif->bif_state == BSTP_IFSTATE_L1BLOCKING) {
469 			continue;
470 		}
471 
472 		if (bif->bif_peer_root > designated_root)
473 			continue;
474 		if (bif->bif_peer_root < designated_root)
475 			goto set_port;
476 
477 		/*
478 		 * NOTE: The designated_cost temporary variable already added
479 		 *	 in the path code of the related root port.
480 		 */
481 		if (bif->bif_peer_cost + bif->bif_path_cost > designated_cost)
482 			continue;
483 		if (bif->bif_peer_cost + bif->bif_path_cost < designated_cost)
484 			goto set_port;
485 
486 		if (bif->bif_peer_bridge > designated_bridge)
487 			continue;
488 		if (bif->bif_peer_bridge < designated_bridge)
489 			goto set_port;
490 
491 		if (bif->bif_peer_port > designated_port)
492 			continue;
493 		if (bif->bif_peer_port < designated_port)
494 			goto set_port;
495 
496 		/*
497 		 * Same root, path cost, bridge, and port.  Set the root
498 		 * only if we do not already have it.
499 		 */
500 		if (root_port)
501 			continue;
502 
503 		/*
504 		 * New root port (from peers)
505 		 *
506 		 * NOTE: Temporarily add bif_path_cost into the designated
507 		 *	 cost to reduce complexity in the loop, it will be
508 		 *	 subtracted out when we are done.
509 		 */
510 set_port:
511 		designated_root = bif->bif_peer_root;
512 		designated_cost = bif->bif_peer_cost + bif->bif_path_cost;
513 		designated_bridge = bif->bif_peer_bridge;
514 		designated_port = bif->bif_peer_port;
515 		root_port = bif;
516 	}
517 
518 	/*
519 	 * root_port will be NULL at the start here if all of our
520 	 * peers are aged or are not as good a root as our bridge would
521 	 * be.  It can also be NULL due to all related links being
522 	 * disabled.
523 	 *
524 	 * If the root winds up being our bridge scan again against local
525 	 * information.  Unconditionally update IFBIF_DESIGNATED.
526 	 */
527 	TAILQ_FOREACH(bif, &sc->sc_iflists[mycpuid], bif_next) {
528 		bif->bif_flags &= ~(IFBIF_DESIGNATED | IFBIF_ROOT);
529 		if ((bif->bif_flags & IFBIF_STP) == 0)
530 			continue;
531 		if (bif->bif_state == BSTP_IFSTATE_DISABLED ||
532 		    bif->bif_state == BSTP_IFSTATE_L1BLOCKING) {
533 			continue;
534 		}
535 
536 		/*
537 		 * Set DESIGNATED for an aged or unknown peer.
538 		 */
539 		if (bif->bif_peer_bridge == 0xFFFFFFFFFFFFFFFFLLU)
540 			bif->bif_flags |= IFBIF_DESIGNATED;
541 		if (designated_root != sc->sc_bridge_id)
542 			continue;
543 
544 		/*
545 		 * This is only reached if our bridge is the root bridge,
546 		 * select the root port (IFBIF_DESIGNATED is set at the
547 		 * end).
548 		 *
549 		 * We do NOT use peer info here.
550 		 */
551 		if (bif->bif_path_cost > designated_cost)
552 			continue;
553 		if (bif->bif_path_cost < designated_cost)
554 			goto set_port2;
555 
556 		if (bif->bif_port_id > designated_port)
557 			continue;
558 		if (bif->bif_port_id < designated_port)
559 			goto set_port2;
560 		/* degenerate case (possible peer collision w/our key */
561 
562 		/*
563 		 * New port
564 		 */
565 set_port2:
566 		designated_cost = bif->bif_path_cost;
567 		designated_bridge = sc->sc_bridge_id;
568 		designated_port = bif->bif_port_id;
569 		root_port = bif;
570 	}
571 
572 	/*
573 	 * Update aggregate information.  The selected root port always
574 	 * becomes a designated port (along with aged ports).  This can
575 	 * either be the port whos peer is closest to the root or it
576 	 * can be one of our ports if our bridge is the root.
577 	 *
578 	 * The root cost we record in sc_designated_root does not include
579 	 * bif_path_cost of the root port, since we may transmit this
580 	 * out of any port we will add the cost back in later on on
581 	 * a per-port basis.
582 	 *
583 	 * root_port can be NULL here (if all links are disabled)
584 	 */
585 	if (root_port) {
586 		sc->sc_designated_root = designated_root;
587 		sc->sc_designated_cost = designated_cost -
588 					 root_port->bif_path_cost;
589 		sc->sc_designated_bridge = designated_bridge;
590 		sc->sc_designated_port = designated_port;
591 		root_port->bif_flags |= IFBIF_DESIGNATED | IFBIF_ROOT;
592 	} else {
593 		sc->sc_designated_root = designated_root;
594 		sc->sc_designated_cost = designated_cost;
595 		sc->sc_designated_bridge = designated_bridge;
596 		sc->sc_designated_port = designated_port;
597 	}
598 	sc->sc_root_port = root_port;
599 }
600 
601 /*
602  * Calculate the desired state for each interface link on our bridge.
603  *
604  * The best port will match against sc->sc_root_port (whether we are root
605  * or whether that port is the closest to the root).  We push this port
606  * towards a FORWARDING state.
607  *
608  * Next come designated ports, either aged ports or ports with no peer info
609  * (yet), or the peer who is closest to the root. We push this port towards
610  * a FORWARDING state as well.
611  *
612  * Any remaining ports are pushed towards a BLOCKING state.  Both sides of
613  * the port (us and our peer) should wind up placing the two ends in this
614  * state or bad things happen.
615  */
616 static void
617 bstp_port_state_selection(struct bridge_softc *sc)
618 {
619 	struct bridge_iflist *bif, *nbif;
620 
621 	TAILQ_FOREACH_MUTABLE(bif, &sc->sc_iflists[mycpuid], bif_next, nbif) {
622 		if ((bif->bif_flags & IFBIF_STP) == 0)
623 			continue;
624 		if (sc->sc_root_port &&
625 		    bif->bif_info == sc->sc_root_port->bif_info) {
626 			bif->bif_config_pending = 0;
627 			bif->bif_topology_change_acknowledge = 0;
628 			bstp_make_forwarding(sc, bif);
629 		} else if (bif->bif_flags & IFBIF_DESIGNATED) {
630 			bstp_timer_stop(&bif->bif_message_age_timer);
631 			bstp_make_forwarding(sc, bif);
632 		} else {
633 			bif->bif_config_pending = 0;
634 			bif->bif_topology_change_acknowledge = 0;
635 			bstp_make_blocking(sc, bif);
636 		}
637 
638 		if (nbif != NULL && !nbif->bif_onlist) {
639 			KKASSERT(bif->bif_onlist);
640 			nbif = TAILQ_NEXT(bif, bif_next);
641 		}
642 	}
643 }
644 
645 /*
646  * Clear peer info, effectively makes the port looked aged out.
647  * It becomes a designated go-to port.
648  */
649 static void
650 bstp_clear_peer_info(struct bridge_softc *sc, struct bridge_iflist *bif)
651 {
652 	bif->bif_peer_root = 0xFFFFFFFFFFFFFFFFLLU;
653 	bif->bif_peer_cost = 0xFFFFFFFFU;
654 	bif->bif_peer_bridge = 0xFFFFFFFFFFFFFFFFLLU;
655 	bif->bif_peer_port = 0xFFFFU;
656 
657 	if (bif->bif_state != BSTP_IFSTATE_DISABLED &&
658 	    bif->bif_state != BSTP_IFSTATE_L1BLOCKING) {
659 		bif->bif_flags |= IFBIF_DESIGNATED;
660 	}
661 }
662 
663 static void
664 bstp_make_forwarding(struct bridge_softc *sc, struct bridge_iflist *bif)
665 {
666 	if (bif->bif_state == BSTP_IFSTATE_BLOCKING ||
667 	    bif->bif_state == BSTP_IFSTATE_BONDED) {
668 		bstp_set_port_state(bif, BSTP_IFSTATE_LISTENING);
669 		bstp_timer_start(&bif->bif_forward_delay_timer, 0);
670 	}
671 }
672 
673 static void
674 bstp_make_blocking(struct bridge_softc *sc, struct bridge_iflist *bif)
675 {
676 	if (bif->bif_state != BSTP_IFSTATE_DISABLED &&
677 	    bif->bif_state != BSTP_IFSTATE_BLOCKING &&
678 	    bif->bif_state != BSTP_IFSTATE_BONDED &&
679 	    bif->bif_state != BSTP_IFSTATE_L1BLOCKING) {
680 		if ((bif->bif_state == BSTP_IFSTATE_FORWARDING) ||
681 		    (bif->bif_state == BSTP_IFSTATE_LEARNING)) {
682 			if (bif->bif_change_detection_enabled) {
683 				bstp_topology_change_detection(sc);
684 			}
685 		}
686 		bstp_set_port_state(bif, BSTP_IFSTATE_BLOCKING);
687 		bridge_rtdelete(sc, bif->bif_ifp, IFBF_FLUSHDYN);
688 		bstp_timer_stop(&bif->bif_forward_delay_timer);
689 		if (sc->sc_ifp->if_flags & IFF_LINK2)
690 			bstp_adjust_bonded_states(sc, bif);
691 	}
692 }
693 
694 static void
695 bstp_make_l1blocking(struct bridge_softc *sc, struct bridge_iflist *bif)
696 {
697 	int was_forwarding = (bif->bif_state == BSTP_IFSTATE_FORWARDING);
698 
699 	switch(bif->bif_state) {
700 	case BSTP_IFSTATE_LISTENING:
701 	case BSTP_IFSTATE_LEARNING:
702 	case BSTP_IFSTATE_FORWARDING:
703 	case BSTP_IFSTATE_BLOCKING:
704 	case BSTP_IFSTATE_BONDED:
705 		bstp_set_port_state(bif, BSTP_IFSTATE_L1BLOCKING);
706 		bridge_rtdelete(sc, bif->bif_ifp, IFBF_FLUSHDYN);
707 		bstp_timer_stop(&bif->bif_forward_delay_timer);
708 		bstp_timer_stop(&bif->bif_link1_timer);
709 		if (bif->bif_flags & IFBIF_DESIGNATED) {
710 			bif->bif_flags &= ~IFBIF_DESIGNATED;
711 			bstp_configuration_update(sc);
712 			bstp_port_state_selection(sc);
713 		}
714 		if (was_forwarding && (sc->sc_ifp->if_flags & IFF_LINK2))
715 			bstp_adjust_bonded_states(sc, bif);
716 		break;
717 	default:
718 		break;
719 	}
720 }
721 
722 /*
723  * Member (bif) changes to or from a FORWARDING state.  All members in the
724  * same bonding group which are in a BLOCKING or BONDED state must be set
725  * to either BLOCKING or BONDED based on whether any members in the bonding
726  * group remain in the FORWARDING state.
727  *
728  * Going between the BLOCKING and BONDED states does not require a
729  * configuration update.
730  */
731 static void
732 bstp_adjust_bonded_states(struct bridge_softc *sc, struct bridge_iflist *obif)
733 {
734 	struct bridge_iflist *bif;
735 	int state = BSTP_IFSTATE_BLOCKING;
736 
737 	TAILQ_FOREACH(bif, &sc->sc_iflists[mycpuid], bif_next) {
738 		if ((bif->bif_flags & IFBIF_STP) == 0)
739 			continue;
740 		if (bif->bif_state != BSTP_IFSTATE_FORWARDING)
741 			continue;
742 		if (memcmp(IF_LLADDR(bif->bif_ifp), IF_LLADDR(obif->bif_ifp),
743 			   ETHER_ADDR_LEN) != 0) {
744 			continue;
745 		}
746 		state = BSTP_IFSTATE_BONDED;
747 		break;
748 	}
749 	TAILQ_FOREACH(bif, &sc->sc_iflists[mycpuid], bif_next) {
750 		if ((bif->bif_flags & IFBIF_STP) == 0)
751 			continue;
752 		if (bif->bif_state != BSTP_IFSTATE_BLOCKING &&
753 		    bif->bif_state != BSTP_IFSTATE_BONDED) {
754 			continue;
755 		}
756 		if (memcmp(IF_LLADDR(bif->bif_ifp), IF_LLADDR(obif->bif_ifp),
757 			   ETHER_ADDR_LEN) != 0) {
758 			continue;
759 		}
760 		if (bif->bif_bond_weight == 0)
761 			bif->bif_state = BSTP_IFSTATE_BLOCKING;
762 		else
763 			bif->bif_state = state;
764 	}
765 }
766 
767 static void
768 bstp_set_port_state(struct bridge_iflist *bif, uint8_t state)
769 {
770 	bif->bif_state = state;
771 }
772 
773 static void
774 bstp_topology_change_detection(struct bridge_softc *sc)
775 {
776 	if (bstp_root_bridge(sc)) {
777 		sc->sc_topology_change = 1;
778 		bstp_timer_start(&sc->sc_topology_change_timer, 0);
779 	} else if (!sc->sc_topology_change_detected) {
780 		bstp_transmit_tcn(sc);
781 		bstp_timer_start(&sc->sc_tcn_timer, 0);
782 	}
783 	sc->sc_topology_change_detected = 1;
784 }
785 
786 static void
787 bstp_topology_change_acknowledged(struct bridge_softc *sc)
788 {
789 	sc->sc_topology_change_detected = 0;
790 	bstp_timer_stop(&sc->sc_tcn_timer);
791 }
792 
793 static void
794 bstp_acknowledge_topology_change(struct bridge_softc *sc,
795 				 struct bridge_iflist *bif)
796 {
797 	bif->bif_topology_change_acknowledge = 1;
798 	bstp_transmit_config(sc, bif);
799 }
800 
801 void
802 bstp_input(struct bridge_softc *sc, struct bridge_iflist *bif, struct mbuf *m)
803 {
804 	struct ether_header *eh;
805 	struct bstp_tbpdu tpdu;
806 	struct bstp_cbpdu cpdu;
807 	struct bstp_config_unit cu;
808 	struct bstp_tcn_unit tu;
809 	uint16_t len;
810 
811 	if ((bif->bif_flags & IFBIF_STP) == 0)
812 		goto out;
813 
814 	/*
815 	 * The L1BLOCKING (ping pong failover) test needs to reset the
816 	 * timer if LINK1 is active.
817 	 */
818 	if (bif->bif_state == BSTP_IFSTATE_L1BLOCKING) {
819 		bstp_set_port_state(bif, BSTP_IFSTATE_BLOCKING);
820 		if (sc->sc_ifp->if_flags & IFF_LINK1)
821 			bstp_timer_start(&bif->bif_link1_timer, 0);
822 		bstp_make_forwarding(sc, bif);
823 	} else if (sc->sc_ifp->if_flags & IFF_LINK1) {
824 		bstp_timer_start(&bif->bif_link1_timer, 0);
825 	}
826 
827 	eh = mtod(m, struct ether_header *);
828 
829 	len = ntohs(eh->ether_type);
830 	if (len < sizeof(tpdu))
831 		goto out;
832 
833 	m_adj(m, ETHER_HDR_LEN);
834 
835 	if (m->m_pkthdr.len > len)
836 		m_adj(m, len - m->m_pkthdr.len);
837 	if (m->m_len < sizeof(tpdu) &&
838 	    (m = m_pullup(m, sizeof(tpdu))) == NULL)
839 		goto out;
840 
841 	memcpy(&tpdu, mtod(m, caddr_t), sizeof(tpdu));
842 
843 	if (tpdu.tbu_dsap != LLC_8021D_LSAP ||
844 	    tpdu.tbu_ssap != LLC_8021D_LSAP ||
845 	    tpdu.tbu_ctl != LLC_UI)
846 		goto out;
847 	if (tpdu.tbu_protoid != 0 || tpdu.tbu_protover != 0)
848 		goto out;
849 
850 	switch (tpdu.tbu_bpdutype) {
851 	case BSTP_MSGTYPE_TCN:
852 		tu.tu_message_type = tpdu.tbu_bpdutype;
853 		bstp_received_tcn_bpdu(sc, bif, &tu);
854 		break;
855 	case BSTP_MSGTYPE_CFG:
856 		if (m->m_len < sizeof(cpdu) &&
857 		    (m = m_pullup(m, sizeof(cpdu))) == NULL)
858 			goto out;
859 		memcpy(&cpdu, mtod(m, caddr_t), sizeof(cpdu));
860 
861 		cu.cu_rootid =
862 		    (((uint64_t)ntohs(cpdu.cbu_rootpri)) << 48) |
863 		    (((uint64_t)cpdu.cbu_rootaddr[0]) << 40) |
864 		    (((uint64_t)cpdu.cbu_rootaddr[1]) << 32) |
865 		    (((uint64_t)cpdu.cbu_rootaddr[2]) << 24) |
866 		    (((uint64_t)cpdu.cbu_rootaddr[3]) << 16) |
867 		    (((uint64_t)cpdu.cbu_rootaddr[4]) << 8) |
868 		    (((uint64_t)cpdu.cbu_rootaddr[5]) << 0);
869 
870 		cu.cu_bridge_id =
871 		    (((uint64_t)ntohs(cpdu.cbu_bridgepri)) << 48) |
872 		    (((uint64_t)cpdu.cbu_bridgeaddr[0]) << 40) |
873 		    (((uint64_t)cpdu.cbu_bridgeaddr[1]) << 32) |
874 		    (((uint64_t)cpdu.cbu_bridgeaddr[2]) << 24) |
875 		    (((uint64_t)cpdu.cbu_bridgeaddr[3]) << 16) |
876 		    (((uint64_t)cpdu.cbu_bridgeaddr[4]) << 8) |
877 		    (((uint64_t)cpdu.cbu_bridgeaddr[5]) << 0);
878 
879 		cu.cu_root_path_cost = ntohl(cpdu.cbu_rootpathcost);
880 		cu.cu_message_age = ntohs(cpdu.cbu_messageage);
881 		cu.cu_max_age = ntohs(cpdu.cbu_maxage);
882 		cu.cu_hello_time = ntohs(cpdu.cbu_hellotime);
883 		cu.cu_forward_delay = ntohs(cpdu.cbu_forwarddelay);
884 		cu.cu_port_id = ntohs(cpdu.cbu_portid);
885 		cu.cu_message_type = cpdu.cbu_bpdutype;
886 		cu.cu_topology_change_acknowledgment =
887 		    (cpdu.cbu_flags & BSTP_FLAG_TCA) ? 1 : 0;
888 		cu.cu_topology_change =
889 		    (cpdu.cbu_flags & BSTP_FLAG_TC) ? 1 : 0;
890 		bstp_received_config_bpdu(sc, bif, &cu);
891 		break;
892 	default:
893 		goto out;
894 	}
895 out:
896 	if (m)
897 		m_freem(m);
898 }
899 
900 static void
901 bstp_received_config_bpdu(struct bridge_softc *sc, struct bridge_iflist *bif,
902 			  struct bstp_config_unit *cu)
903 {
904 	int iamroot;
905 
906 	iamroot = bstp_root_bridge(sc);
907 
908 	if (bif->bif_state != BSTP_IFSTATE_DISABLED) {
909 		/*
910 		 * Record information from peer.  The peer_cost field
911 		 * does not include the local bif->bif_path_cost, it will
912 		 * be added in as needed (since it can be modified manually
913 		 * this way we don't have to worry about fixups).
914 		 */
915 		bif->bif_peer_root = cu->cu_rootid;
916 		bif->bif_peer_cost = cu->cu_root_path_cost;
917 		bif->bif_peer_bridge = cu->cu_bridge_id;
918 		bif->bif_peer_port = cu->cu_port_id;
919 
920 		if (bstp_supersedes_port_info(sc, bif)) {
921 			bstp_record_config_information(sc, bif, cu);
922 			bstp_configuration_update(sc);
923 			bstp_port_state_selection(sc);
924 
925 			/*
926 			 * If our bridge loses its root status (?)
927 			 *
928 			 * Hello's (unsolicited CFG packets) are generated
929 			 * every hello period of LINK1 is set, otherwise
930 			 * we are no longer the root bridge and must stop
931 			 * generating unsolicited CFG packets.
932 			 */
933 			if (iamroot && bstp_root_bridge(sc) == 0) {
934 				if ((sc->sc_ifp->if_flags & IFF_LINK1) == 0)
935 					bstp_timer_stop(&sc->sc_hello_timer);
936 
937 				if (sc->sc_topology_change_detected) {
938 					bstp_timer_stop(
939 					    &sc->sc_topology_change_timer);
940 					bstp_transmit_tcn(sc);
941 					bstp_timer_start(&sc->sc_tcn_timer, 0);
942 				}
943 			}
944 
945 			if (sc->sc_root_port &&
946 			    bif->bif_info == sc->sc_root_port->bif_info) {
947 				bstp_record_config_timeout_values(sc, cu);
948 				bstp_config_bpdu_generation(sc);
949 
950 				if (cu->cu_topology_change_acknowledgment)
951 					bstp_topology_change_acknowledged(sc);
952 			}
953 		} else if (bif->bif_flags & IFBIF_DESIGNATED) {
954 			/*
955 			 * Update designated ports (aged out peers or
956 			 * the port closest to the root) at a faster pace.
957 			 *
958 			 * Clear our designated flag if we aren't marked
959 			 * as the root port.
960 			 */
961 			bstp_transmit_config(sc, bif);
962 			if ((bif->bif_flags & IFBIF_ROOT) == 0) {
963 				bif->bif_flags &= ~IFBIF_DESIGNATED;
964 				bstp_configuration_update(sc);
965 				bstp_port_state_selection(sc);
966 			}
967 		}
968 	}
969 }
970 
971 static void
972 bstp_received_tcn_bpdu(struct bridge_softc *sc, struct bridge_iflist *bif,
973 		       struct bstp_tcn_unit *tcn)
974 {
975 	if (bif->bif_state != BSTP_IFSTATE_DISABLED &&
976 	    (bif->bif_flags & IFBIF_DESIGNATED)) {
977 		bstp_topology_change_detection(sc);
978 		bstp_acknowledge_topology_change(sc, bif);
979 	}
980 }
981 
982 /*
983  * link1 forces continuous hello's (the bridge interface must be cycled
984  * to start them up), so keep the timer hot if that is the case, otherwise
985  * only send HELLO's if we are the root.
986  */
987 static void
988 bstp_hello_timer_expiry(struct bridge_softc *sc)
989 {
990 	bstp_config_bpdu_generation(sc);
991 
992 	if ((sc->sc_ifp->if_flags & IFF_LINK1) || bstp_root_bridge(sc))
993 		bstp_timer_start(&sc->sc_hello_timer, 0);
994 }
995 
996 static void
997 bstp_message_age_timer_expiry(struct bridge_softc *sc,
998 			      struct bridge_iflist *bif)
999 {
1000 	int iamroot;
1001 
1002 	iamroot = bstp_root_bridge(sc);
1003 	bstp_clear_peer_info(sc, bif);
1004 	bstp_configuration_update(sc);
1005 	bstp_port_state_selection(sc);
1006 
1007 	/*
1008 	 * If we've become the root and were not the root before
1009 	 * we have some cleanup to do.  This also occurs if we
1010 	 * wind up being completely isolated.
1011 	 */
1012 	if (iamroot == 0 && bstp_root_bridge(sc)) {
1013 		sc->sc_max_age = sc->sc_bridge_max_age;
1014 		sc->sc_hello_time = sc->sc_bridge_hello_time;
1015 		sc->sc_forward_delay = sc->sc_bridge_forward_delay;
1016 
1017 		bstp_topology_change_detection(sc);
1018 		bstp_timer_stop(&sc->sc_tcn_timer);
1019 		bstp_config_bpdu_generation(sc);
1020 		bstp_timer_start(&sc->sc_hello_timer, 0);
1021 	}
1022 }
1023 
1024 static void
1025 bstp_forward_delay_timer_expiry(struct bridge_softc *sc,
1026 				struct bridge_iflist *bif)
1027 {
1028 	if (bif->bif_state == BSTP_IFSTATE_LISTENING) {
1029 		bstp_set_port_state(bif, BSTP_IFSTATE_LEARNING);
1030 		bstp_timer_start(&bif->bif_forward_delay_timer, 0);
1031 	} else if (bif->bif_state == BSTP_IFSTATE_LEARNING) {
1032 		bstp_set_port_state(bif, BSTP_IFSTATE_FORWARDING);
1033 		if (sc->sc_designated_bridge == sc->sc_bridge_id &&
1034 		    bif->bif_change_detection_enabled) {
1035 			bstp_topology_change_detection(sc);
1036 		}
1037 		if (sc->sc_ifp->if_flags & IFF_LINK2)
1038 			bstp_adjust_bonded_states(sc, bif);
1039 	}
1040 }
1041 
1042 static void
1043 bstp_tcn_timer_expiry(struct bridge_softc *sc)
1044 {
1045 	bstp_transmit_tcn(sc);
1046 	bstp_timer_start(&sc->sc_tcn_timer, 0);
1047 }
1048 
1049 static void
1050 bstp_topology_change_timer_expiry(struct bridge_softc *sc)
1051 {
1052 	sc->sc_topology_change_detected = 0;
1053 	sc->sc_topology_change = 0;
1054 }
1055 
1056 static void
1057 bstp_hold_timer_expiry(struct bridge_softc *sc, struct bridge_iflist *bif)
1058 {
1059 	if (bif->bif_config_pending)
1060 		bstp_transmit_config(sc, bif);
1061 }
1062 
1063 /*
1064  * If no traffic received directly on this port for the specified
1065  * period with link1 set we go into a special blocking mode to
1066  * fail-over traffic to another port.
1067  */
1068 static void
1069 bstp_link1_timer_expiry(struct bridge_softc *sc, struct bridge_iflist *bif)
1070 {
1071 	if (sc->sc_ifp->if_flags & IFF_LINK1)
1072 		bstp_make_l1blocking(sc, bif);
1073 }
1074 
1075 static int
1076 bstp_addr_cmp(const uint8_t *a, const uint8_t *b)
1077 {
1078 	int i, d;
1079 
1080 	for (i = 0, d = 0; i < ETHER_ADDR_LEN && d == 0; i++) {
1081 		d = ((int)a[i]) - ((int)b[i]);
1082 	}
1083 
1084 	return (d);
1085 }
1086 
1087 void
1088 bstp_initialization(struct bridge_softc *sc)
1089 {
1090 	struct bridge_iflist *bif, *mif, *nbif;
1091 	u_char *e_addr;
1092 
1093 	KKASSERT(&curthread->td_msgport == BRIDGE_CFGPORT);
1094 
1095 	/*
1096 	 * Figure out our bridge ID, use the lowest-valued MAC.
1097 	 * Include the bridge's own random MAC in the calculation.
1098 	 */
1099 	mif = NULL;
1100 
1101 	TAILQ_FOREACH(bif, &sc->sc_iflists[mycpuid], bif_next) {
1102 		if ((bif->bif_flags & IFBIF_STP) == 0)
1103 			continue;
1104 		if (bif->bif_ifp->if_type != IFT_ETHER)
1105 			continue;
1106 		if (mif == NULL) {
1107 			mif = bif;
1108 			continue;
1109 		}
1110 
1111 		bif->bif_port_id = (bif->bif_priority << 8) |
1112 				   (bif->bif_ifp->if_index & 0xff);
1113 		if (bstp_addr_cmp(IF_LLADDR(bif->bif_ifp),
1114 				  IF_LLADDR(mif->bif_ifp)) < 0) {
1115 			mif = bif;
1116 			continue;
1117 		}
1118 	}
1119 	if (mif == NULL) {
1120 		bstp_stop(sc);
1121 		return;
1122 	}
1123 
1124 	if (bstp_addr_cmp(IF_LLADDR(sc->sc_ifp), IF_LLADDR(mif->bif_ifp)) < 0)
1125 		e_addr = IF_LLADDR(sc->sc_ifp);
1126 	else
1127 		e_addr = IF_LLADDR(mif->bif_ifp);
1128 
1129 	sc->sc_bridge_id =
1130 	    (((uint64_t)sc->sc_bridge_priority) << 48) |
1131 	    (((uint64_t)e_addr[0]) << 40) |
1132 	    (((uint64_t)e_addr[1]) << 32) |
1133 	    (((uint64_t)e_addr[2]) << 24) |
1134 	    (((uint64_t)e_addr[3]) << 16) |
1135 	    (((uint64_t)e_addr[4]) << 8) |
1136 	    (((uint64_t)e_addr[5]));
1137 
1138 	/*
1139 	 * Remainder of setup.
1140 	 */
1141 
1142 	sc->sc_designated_root = sc->sc_bridge_id;
1143 	sc->sc_designated_cost = 0;
1144 	sc->sc_root_port = NULL;
1145 
1146 	sc->sc_max_age = sc->sc_bridge_max_age;
1147 	sc->sc_hello_time = sc->sc_bridge_hello_time;
1148 	sc->sc_forward_delay = sc->sc_bridge_forward_delay;
1149 	sc->sc_topology_change_detected = 0;
1150 	sc->sc_topology_change = 0;
1151 	bstp_timer_stop(&sc->sc_tcn_timer);
1152 	bstp_timer_stop(&sc->sc_topology_change_timer);
1153 
1154 	if (callout_pending(&sc->sc_bstpcallout) == 0)
1155 		callout_reset(&sc->sc_bstpcallout, hz,
1156 		    bstp_tick, sc);
1157 
1158 	TAILQ_FOREACH_MUTABLE(bif, &sc->sc_iflists[mycpuid], bif_next, nbif) {
1159 		if (sc->sc_ifp->if_flags & IFF_LINK1)
1160 			bstp_timer_start(&bif->bif_link1_timer, 0);
1161 		if (bif->bif_flags & IFBIF_STP)
1162 			bstp_ifupdstatus(sc, bif);
1163 		else
1164 			bstp_disable_port(sc, bif);
1165 
1166 		if (nbif != NULL && !nbif->bif_onlist) {
1167 			KKASSERT(bif->bif_onlist);
1168 			nbif = TAILQ_NEXT(bif, bif_next);
1169 		}
1170 	}
1171 
1172 	bstp_port_state_selection(sc);
1173 	bstp_config_bpdu_generation(sc);
1174 	bstp_timer_start(&sc->sc_hello_timer, 0);
1175 }
1176 
1177 void
1178 bstp_stop(struct bridge_softc *sc)
1179 {
1180 	struct bridge_iflist *bif;
1181 	struct lwkt_msg *lmsg;
1182 
1183 	KKASSERT(&curthread->td_msgport == BRIDGE_CFGPORT);
1184 
1185 	TAILQ_FOREACH(bif, &sc->sc_iflists[mycpuid], bif_next) {
1186 		bstp_set_port_state(bif, BSTP_IFSTATE_DISABLED);
1187 		bstp_timer_stop(&bif->bif_hold_timer);
1188 		bstp_timer_stop(&bif->bif_message_age_timer);
1189 		bstp_timer_stop(&bif->bif_forward_delay_timer);
1190 		bstp_timer_stop(&bif->bif_link1_timer);
1191 	}
1192 
1193 	callout_stop(&sc->sc_bstpcallout);
1194 
1195 	bstp_timer_stop(&sc->sc_topology_change_timer);
1196 	bstp_timer_stop(&sc->sc_tcn_timer);
1197 	bstp_timer_stop(&sc->sc_hello_timer);
1198 
1199 	crit_enter();
1200 	lmsg = &sc->sc_bstptimemsg.lmsg;
1201 	if ((lmsg->ms_flags & MSGF_DONE) == 0) {
1202 		/* Pending to be processed; drop it */
1203 		lwkt_dropmsg(lmsg);
1204 	}
1205 	crit_exit();
1206 }
1207 
1208 static void
1209 bstp_initialize_port(struct bridge_softc *sc, struct bridge_iflist *bif)
1210 {
1211 	int needs_adjust = (bif->bif_state == BSTP_IFSTATE_FORWARDING ||
1212 			    bif->bif_state == BSTP_IFSTATE_BLOCKING ||
1213 			    bif->bif_state == BSTP_IFSTATE_BONDED);
1214 
1215 	bstp_set_port_state(bif, BSTP_IFSTATE_BLOCKING);
1216 	bstp_clear_peer_info(sc, bif);
1217 	bif->bif_topology_change_acknowledge = 0;
1218 	bif->bif_config_pending = 0;
1219 	bif->bif_change_detection_enabled = 1;
1220 	bstp_timer_stop(&bif->bif_message_age_timer);
1221 	bstp_timer_stop(&bif->bif_forward_delay_timer);
1222 	bstp_timer_stop(&bif->bif_hold_timer);
1223 	bstp_timer_stop(&bif->bif_link1_timer);
1224 	if (needs_adjust && (sc->sc_ifp->if_flags & IFF_LINK2))
1225 		bstp_adjust_bonded_states(sc, bif);
1226 }
1227 
1228 static void
1229 bstp_enable_port(struct bridge_softc *sc, struct bridge_iflist *bif)
1230 {
1231 	bstp_initialize_port(sc, bif);
1232 	if (sc->sc_ifp->if_flags & IFF_LINK1)
1233 		bstp_timer_start(&bif->bif_link1_timer, 0);
1234 	bstp_port_state_selection(sc);
1235 }
1236 
1237 static void
1238 bstp_disable_port(struct bridge_softc *sc, struct bridge_iflist *bif)
1239 {
1240 	int was_forwarding = (bif->bif_state == BSTP_IFSTATE_FORWARDING);
1241 	int iamroot;
1242 
1243 	iamroot = bstp_root_bridge(sc);
1244 
1245 	bstp_clear_peer_info(sc, bif);
1246 	bstp_set_port_state(bif, BSTP_IFSTATE_DISABLED);
1247 	bif->bif_topology_change_acknowledge = 0;
1248 	bif->bif_config_pending = 0;
1249 	bstp_timer_stop(&bif->bif_message_age_timer);
1250 	bstp_timer_stop(&bif->bif_forward_delay_timer);
1251 	bstp_timer_stop(&bif->bif_link1_timer);
1252 	bstp_configuration_update(sc);
1253 	bstp_port_state_selection(sc);
1254 	bridge_rtdelete(sc, bif->bif_ifp, IFBF_FLUSHDYN);
1255 	if (was_forwarding && (sc->sc_ifp->if_flags & IFF_LINK2))
1256 		bstp_adjust_bonded_states(sc, bif);
1257 
1258 	if (iamroot == 0 && bstp_root_bridge(sc)) {
1259 		sc->sc_max_age = sc->sc_bridge_max_age;
1260 		sc->sc_hello_time = sc->sc_bridge_hello_time;
1261 		sc->sc_forward_delay = sc->sc_bridge_forward_delay;
1262 
1263 		bstp_topology_change_detection(sc);
1264 		bstp_timer_stop(&sc->sc_tcn_timer);
1265 		bstp_config_bpdu_generation(sc);
1266 		bstp_timer_start(&sc->sc_hello_timer, 0);
1267 	}
1268 }
1269 
1270 void
1271 bstp_linkstate(struct ifnet *ifp, int state)
1272 {
1273 	struct bridge_softc *sc;
1274 	struct bridge_iflist *bif;
1275 
1276 	sc = ifp->if_bridge;
1277 	ifnet_serialize_all(sc->sc_ifp);
1278 
1279 	/*
1280 	 * bstp_ifupdstatus() may block, but it is the last
1281 	 * operation of the member iface iteration, so we
1282 	 * don't need to use LIST_FOREACH_MUTABLE()+bif_onlist
1283 	 * check here.
1284 	 */
1285 	TAILQ_FOREACH(bif, &sc->sc_iflists[mycpuid], bif_next) {
1286 		if ((bif->bif_flags & IFBIF_STP) == 0)
1287 			continue;
1288 
1289 		if (bif->bif_ifp == ifp) {
1290 			bstp_ifupdstatus(sc, bif);
1291 			break;
1292 		}
1293 	}
1294 	ifnet_deserialize_all(sc->sc_ifp);
1295 }
1296 
1297 static void
1298 bstp_ifupdstatus(struct bridge_softc *sc, struct bridge_iflist *bif)
1299 {
1300 	struct ifnet *ifp = bif->bif_ifp;
1301 	struct ifmediareq ifmr;
1302 	int error = 0;
1303 
1304 	bzero((char *)&ifmr, sizeof(ifmr));
1305 	ifnet_serialize_all(ifp);
1306 	error = (*ifp->if_ioctl)(ifp, SIOCGIFMEDIA, (caddr_t)&ifmr, NULL);
1307 	ifnet_deserialize_all(ifp);
1308 
1309 	if ((error == 0) && (ifp->if_flags & IFF_UP)) {
1310 	 	if (ifmr.ifm_status & IFM_ACTIVE) {
1311 			if (bif->bif_state == BSTP_IFSTATE_DISABLED)
1312 				bstp_enable_port(sc, bif);
1313 
1314 		} else {
1315 			if (bif->bif_state != BSTP_IFSTATE_DISABLED)
1316 				bstp_disable_port(sc, bif);
1317 		}
1318 		return;
1319 	}
1320 
1321 	if (bif->bif_state != BSTP_IFSTATE_DISABLED)
1322 		bstp_disable_port(sc, bif);
1323 }
1324 
1325 static void
1326 bstp_tick(void *arg)
1327 {
1328 	struct bridge_softc *sc = arg;
1329 	struct lwkt_msg *lmsg;
1330 
1331 	KKASSERT(mycpuid == BRIDGE_CFGCPU);
1332 
1333 	crit_enter();
1334 
1335 	if (callout_pending(&sc->sc_bstpcallout) ||
1336 	    !callout_active(&sc->sc_bstpcallout)) {
1337 		crit_exit();
1338 		return;
1339 	}
1340 	callout_deactivate(&sc->sc_bstpcallout);
1341 
1342 	lmsg = &sc->sc_bstptimemsg.lmsg;
1343 	KKASSERT(lmsg->ms_flags & MSGF_DONE);
1344 	lwkt_sendmsg(BRIDGE_CFGPORT, lmsg);
1345 
1346 	crit_exit();
1347 }
1348 
1349 void
1350 bstp_tick_handler(netmsg_t msg)
1351 {
1352 	struct bridge_softc *sc = msg->lmsg.u.ms_resultp;
1353 	struct bridge_iflist *bif;
1354 
1355 	KKASSERT(&curthread->td_msgport == BRIDGE_CFGPORT);
1356 	crit_enter();
1357 	/* Reply ASAP */
1358 	lwkt_replymsg(&msg->lmsg, 0);
1359 	crit_exit();
1360 
1361 	ifnet_serialize_all(sc->sc_ifp);
1362 
1363 	/*
1364 	 * NOTE:
1365 	 * We don't need to worry that member iface is ripped
1366 	 * from the per-cpu list during the blocking operation
1367 	 * in the loop body, since deletion is serialized by
1368 	 * BRIDGE_CFGPORT
1369 	 */
1370 
1371 	TAILQ_FOREACH(bif, &sc->sc_iflists[mycpuid], bif_next) {
1372 		if ((bif->bif_flags & IFBIF_STP) == 0)
1373 			continue;
1374 		/*
1375 		 * XXX This can cause a lag in "link does away"
1376 		 * XXX and "spanning tree gets updated".  We need
1377 		 * XXX come sort of callback from the link state
1378 		 * XXX update code to kick spanning tree.
1379 		 * XXX --thorpej@NetBSD.org
1380 		 */
1381 		bstp_ifupdstatus(sc, bif);
1382 	}
1383 
1384 	if (bstp_timer_expired(&sc->sc_hello_timer, sc->sc_hello_time))
1385 		bstp_hello_timer_expiry(sc);
1386 
1387 	if (bstp_timer_expired(&sc->sc_tcn_timer, sc->sc_bridge_hello_time))
1388 		bstp_tcn_timer_expiry(sc);
1389 
1390 	if (bstp_timer_expired(&sc->sc_topology_change_timer,
1391 	    sc->sc_topology_change_time))
1392 		bstp_topology_change_timer_expiry(sc);
1393 
1394 	TAILQ_FOREACH(bif, &sc->sc_iflists[mycpuid], bif_next) {
1395 		if ((bif->bif_flags & IFBIF_STP) == 0)
1396 			continue;
1397 		if (bstp_timer_expired(&bif->bif_message_age_timer,
1398 		    sc->sc_max_age))
1399 			bstp_message_age_timer_expiry(sc, bif);
1400 	}
1401 
1402 	TAILQ_FOREACH(bif, &sc->sc_iflists[mycpuid], bif_next) {
1403 		if ((bif->bif_flags & IFBIF_STP) == 0)
1404 			continue;
1405 		if (bstp_timer_expired(&bif->bif_forward_delay_timer,
1406 		    sc->sc_forward_delay))
1407 			bstp_forward_delay_timer_expiry(sc, bif);
1408 
1409 		if (bstp_timer_expired(&bif->bif_hold_timer,
1410 		    sc->sc_hold_time))
1411 			bstp_hold_timer_expiry(sc, bif);
1412 
1413 		if (bstp_timer_expired(&bif->bif_link1_timer,
1414 		    sc->sc_hello_time * 10))
1415 			bstp_link1_timer_expiry(sc, bif);
1416 	}
1417 
1418 	if (sc->sc_ifp->if_flags & IFF_RUNNING)
1419 		callout_reset(&sc->sc_bstpcallout, hz, bstp_tick, sc);
1420 
1421 	ifnet_deserialize_all(sc->sc_ifp);
1422 }
1423 
1424 static void
1425 bstp_timer_start(struct bridge_timer *t, uint16_t v)
1426 {
1427 	t->value = v;
1428 	t->active = 1;
1429 }
1430 
1431 static void
1432 bstp_timer_stop(struct bridge_timer *t)
1433 {
1434 	t->value = 0;
1435 	t->active = 0;
1436 }
1437 
1438 static int
1439 bstp_timer_expired(struct bridge_timer *t, uint16_t v)
1440 {
1441 	if (t->active == 0)
1442 		return (0);
1443 	t->value += BSTP_TICK_VAL;
1444 	if (t->value >= v) {
1445 		bstp_timer_stop(t);
1446 		return (1);
1447 	}
1448 	return (0);
1449 
1450 }
1451