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bridgestp.c revision 1.13.10.1
      1 /*	$NetBSD: bridgestp.c,v 1.13.10.1 2009/05/04 08:14:14 yamt Exp $	*/
      2 
      3 /*
      4  * Copyright (c) 2000 Jason L. Wright (jason (at) thought.net)
      5  * All rights reserved.
      6  *
      7  * Redistribution and use in source and binary forms, with or without
      8  * modification, are permitted provided that the following conditions
      9  * are met:
     10  * 1. Redistributions of source code must retain the above copyright
     11  *    notice, this list of conditions and the following disclaimer.
     12  * 2. Redistributions in binary form must reproduce the above copyright
     13  *    notice, this list of conditions and the following disclaimer in the
     14  *    documentation and/or other materials provided with the distribution.
     15  * 3. All advertising materials mentioning features or use of this software
     16  *    must display the following acknowledgement:
     17  *      This product includes software developed by Jason L. Wright
     18  * 4. The name of the author may not be used to endorse or promote products
     19  *    derived from this software without specific prior written permission.
     20  *
     21  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
     22  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
     23  * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
     24  * DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT,
     25  * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
     26  * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
     27  * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
     29  * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
     30  * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     31  * POSSIBILITY OF SUCH DAMAGE.
     32  *
     33  * OpenBSD: bridgestp.c,v 1.5 2001/03/22 03:48:29 jason 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/cdefs.h>
     43 __KERNEL_RCSID(0, "$NetBSD: bridgestp.c,v 1.13.10.1 2009/05/04 08:14:14 yamt Exp $");
     44 
     45 #include <sys/param.h>
     46 #include <sys/systm.h>
     47 #include <sys/mbuf.h>
     48 #include <sys/socket.h>
     49 #include <sys/ioctl.h>
     50 #include <sys/device.h>
     51 #include <sys/kernel.h>
     52 #include <sys/callout.h>
     53 
     54 #include <net/if.h>
     55 #include <net/if_dl.h>
     56 #include <net/if_types.h>
     57 #include <net/if_llc.h>
     58 
     59 #include <net/if_ether.h>
     60 #include <net/if_bridgevar.h>
     61 
     62 /* BPDU message types */
     63 #define	BSTP_MSGTYPE_CFG	0x00		/* Configuration */
     64 #define	BSTP_MSGTYPE_TCN	0x80		/* Topology chg notification */
     65 
     66 /* BPDU flags */
     67 #define	BSTP_FLAG_TC		0x01		/* Topology change */
     68 #define	BSTP_FLAG_TCA		0x80		/* Topology change ack */
     69 
     70 #define	BSTP_MESSAGE_AGE_INCR	(1 * 256)	/* in 256ths of a second */
     71 #define	BSTP_TICK_VAL		(1 * 256)	/* in 256ths of a second */
     72 
     73 /*
     74  * Because BPDU's do not make nicely aligned structures, two different
     75  * declarations are used: bstp_?bpdu (wire representation, packed) and
     76  * bstp_*_unit (internal, nicely aligned version).
     77  */
     78 
     79 /* configuration bridge protocol data unit */
     80 struct bstp_cbpdu {
     81 	uint8_t		cbu_dsap;		/* LLC: destination sap */
     82 	uint8_t		cbu_ssap;		/* LLC: source sap */
     83 	uint8_t		cbu_ctl;		/* LLC: control */
     84 	uint16_t	cbu_protoid;		/* protocol id */
     85 	uint8_t		cbu_protover;		/* protocol version */
     86 	uint8_t		cbu_bpdutype;		/* message type */
     87 	uint8_t		cbu_flags;		/* flags (below) */
     88 
     89 	/* root id */
     90 	uint16_t	cbu_rootpri;		/* root priority */
     91 	uint8_t	cbu_rootaddr[6];	/* root address */
     92 
     93 	uint32_t	cbu_rootpathcost;	/* root path cost */
     94 
     95 	/* bridge id */
     96 	uint16_t	cbu_bridgepri;		/* bridge priority */
     97 	uint8_t		cbu_bridgeaddr[6];	/* bridge address */
     98 
     99 	uint16_t	cbu_portid;		/* port id */
    100 	uint16_t	cbu_messageage;		/* current message age */
    101 	uint16_t	cbu_maxage;		/* maximum age */
    102 	uint16_t	cbu_hellotime;		/* hello time */
    103 	uint16_t	cbu_forwarddelay;	/* forwarding delay */
    104 } __packed;
    105 
    106 /* topology change notification bridge protocol data unit */
    107 struct bstp_tbpdu {
    108 	uint8_t		tbu_dsap;		/* LLC: destination sap */
    109 	uint8_t		tbu_ssap;		/* LLC: source sap */
    110 	uint8_t		tbu_ctl;		/* LLC: control */
    111 	uint16_t	tbu_protoid;		/* protocol id */
    112 	uint8_t		tbu_protover;		/* protocol version */
    113 	uint8_t		tbu_bpdutype;		/* message type */
    114 } __packed;
    115 
    116 const uint8_t bstp_etheraddr[] = { 0x01, 0x80, 0xc2, 0x00, 0x00, 0x00 };
    117 
    118 void	bstp_initialize_port(struct bridge_softc *, struct bridge_iflist *);
    119 void	bstp_ifupdstatus(struct bridge_softc *, struct bridge_iflist *);
    120 void	bstp_enable_port(struct bridge_softc *, struct bridge_iflist *);
    121 void	bstp_disable_port(struct bridge_softc *, struct bridge_iflist *);
    122 void	bstp_enable_change_detection(struct bridge_iflist *);
    123 void	bstp_disable_change_detection(struct bridge_iflist *);
    124 int	bstp_root_bridge(struct bridge_softc *sc);
    125 int	bstp_supersedes_port_info(struct bridge_softc *,
    126 	    struct bridge_iflist *, struct bstp_config_unit *);
    127 int	bstp_designated_port(struct bridge_softc *, struct bridge_iflist *);
    128 int	bstp_designated_for_some_port(struct bridge_softc *);
    129 void	bstp_transmit_config(struct bridge_softc *, struct bridge_iflist *);
    130 void	bstp_transmit_tcn(struct bridge_softc *);
    131 void	bstp_received_config_bpdu(struct bridge_softc *,
    132 	    struct bridge_iflist *, struct bstp_config_unit *);
    133 void	bstp_received_tcn_bpdu(struct bridge_softc *, struct bridge_iflist *,
    134 	    struct bstp_tcn_unit *);
    135 void	bstp_record_config_information(struct bridge_softc *,
    136 	    struct bridge_iflist *, struct bstp_config_unit *);
    137 void	bstp_record_config_timeout_values(struct bridge_softc *,
    138 	    struct bstp_config_unit *);
    139 void	bstp_config_bpdu_generation(struct bridge_softc *);
    140 void	bstp_send_config_bpdu(struct bridge_softc *, struct bridge_iflist *,
    141 	    struct bstp_config_unit *);
    142 void	bstp_configuration_update(struct bridge_softc *);
    143 void	bstp_root_selection(struct bridge_softc *);
    144 void	bstp_designated_port_selection(struct bridge_softc *);
    145 void	bstp_become_designated_port(struct bridge_softc *,
    146 	    struct bridge_iflist *);
    147 void	bstp_port_state_selection(struct bridge_softc *);
    148 void	bstp_make_forwarding(struct bridge_softc *, struct bridge_iflist *);
    149 void	bstp_make_blocking(struct bridge_softc *, struct bridge_iflist *);
    150 void	bstp_set_port_state(struct bridge_iflist *, uint8_t);
    151 void	bstp_set_bridge_priority(struct bridge_softc *, uint64_t);
    152 void	bstp_set_port_priority(struct bridge_softc *, struct bridge_iflist *,
    153 	    uint16_t);
    154 void	bstp_set_path_cost(struct bridge_softc *, struct bridge_iflist *,
    155 	    uint32_t);
    156 void	bstp_topology_change_detection(struct bridge_softc *);
    157 void	bstp_topology_change_acknowledged(struct bridge_softc *);
    158 void	bstp_acknowledge_topology_change(struct bridge_softc *,
    159 	    struct bridge_iflist *);
    160 
    161 void	bstp_tick(void *);
    162 void	bstp_timer_start(struct bridge_timer *, uint16_t);
    163 void	bstp_timer_stop(struct bridge_timer *);
    164 int	bstp_timer_expired(struct bridge_timer *, uint16_t);
    165 
    166 void	bstp_hold_timer_expiry(struct bridge_softc *, struct bridge_iflist *);
    167 void	bstp_message_age_timer_expiry(struct bridge_softc *,
    168 	    struct bridge_iflist *);
    169 void	bstp_forward_delay_timer_expiry(struct bridge_softc *,
    170 	    struct bridge_iflist *);
    171 void	bstp_topology_change_timer_expiry(struct bridge_softc *);
    172 void	bstp_tcn_timer_expiry(struct bridge_softc *);
    173 void	bstp_hello_timer_expiry(struct bridge_softc *);
    174 
    175 void
    176 bstp_transmit_config(struct bridge_softc *sc, struct bridge_iflist *bif)
    177 {
    178 	if (bif->bif_hold_timer.active) {
    179 		bif->bif_config_pending = 1;
    180 		return;
    181 	}
    182 
    183 	bif->bif_config_bpdu.cu_message_type = BSTP_MSGTYPE_CFG;
    184 	bif->bif_config_bpdu.cu_rootid = sc->sc_designated_root;
    185 	bif->bif_config_bpdu.cu_root_path_cost = sc->sc_root_path_cost;
    186 	bif->bif_config_bpdu.cu_bridge_id = sc->sc_bridge_id;
    187 	bif->bif_config_bpdu.cu_port_id = bif->bif_port_id;
    188 
    189 	if (bstp_root_bridge(sc))
    190 		bif->bif_config_bpdu.cu_message_age = 0;
    191 	else
    192 		bif->bif_config_bpdu.cu_message_age =
    193 		    sc->sc_root_port->bif_message_age_timer.value +
    194 		    BSTP_MESSAGE_AGE_INCR;
    195 
    196 	bif->bif_config_bpdu.cu_max_age = sc->sc_max_age;
    197 	bif->bif_config_bpdu.cu_hello_time = sc->sc_hello_time;
    198 	bif->bif_config_bpdu.cu_forward_delay = sc->sc_forward_delay;
    199 	bif->bif_config_bpdu.cu_topology_change_acknowledgment
    200 	    = bif->bif_topology_change_acknowledge;
    201 	bif->bif_config_bpdu.cu_topology_change = sc->sc_topology_change;
    202 
    203 	if (bif->bif_config_bpdu.cu_message_age < sc->sc_max_age) {
    204 		bif->bif_topology_change_acknowledge = 0;
    205 		bif->bif_config_pending = 0;
    206 		bstp_send_config_bpdu(sc, bif, &bif->bif_config_bpdu);
    207 		bstp_timer_start(&bif->bif_hold_timer, 0);
    208 	}
    209 }
    210 
    211 void
    212 bstp_send_config_bpdu(struct bridge_softc *sc, struct bridge_iflist *bif,
    213     struct bstp_config_unit *cu)
    214 {
    215 	struct ifnet *ifp;
    216 	struct mbuf *m;
    217 	struct ether_header *eh;
    218 	struct bstp_cbpdu bpdu;
    219 	int s;
    220 
    221 	ifp = bif->bif_ifp;
    222 
    223 	if ((ifp->if_flags & IFF_RUNNING) == 0)
    224 		return;
    225 
    226 	MGETHDR(m, M_DONTWAIT, MT_DATA);
    227 	if (m == NULL)
    228 		return;
    229 
    230 	eh = mtod(m, struct ether_header *);
    231 
    232 	m->m_pkthdr.rcvif = ifp;
    233 	m->m_pkthdr.len = sizeof(*eh) + sizeof(bpdu);
    234 	m->m_len = m->m_pkthdr.len;
    235 
    236 	bpdu.cbu_ssap = bpdu.cbu_dsap = LLC_8021D_LSAP;
    237 	bpdu.cbu_ctl = LLC_UI;
    238 	bpdu.cbu_protoid = htons(0);
    239 	bpdu.cbu_protover = 0;
    240 	bpdu.cbu_bpdutype = cu->cu_message_type;
    241 	bpdu.cbu_flags = (cu->cu_topology_change ? BSTP_FLAG_TC : 0) |
    242 	    (cu->cu_topology_change_acknowledgment ? BSTP_FLAG_TCA : 0);
    243 
    244 	bpdu.cbu_rootpri = htons(cu->cu_rootid >> 48);
    245 	bpdu.cbu_rootaddr[0] = cu->cu_rootid >> 40;
    246 	bpdu.cbu_rootaddr[1] = cu->cu_rootid >> 32;
    247 	bpdu.cbu_rootaddr[2] = cu->cu_rootid >> 24;
    248 	bpdu.cbu_rootaddr[3] = cu->cu_rootid >> 16;
    249 	bpdu.cbu_rootaddr[4] = cu->cu_rootid >> 8;
    250 	bpdu.cbu_rootaddr[5] = cu->cu_rootid >> 0;
    251 
    252 	bpdu.cbu_rootpathcost = htonl(cu->cu_root_path_cost);
    253 
    254 	bpdu.cbu_bridgepri = htons(cu->cu_rootid >> 48);
    255 	bpdu.cbu_bridgeaddr[0] = cu->cu_rootid >> 40;
    256 	bpdu.cbu_bridgeaddr[1] = cu->cu_rootid >> 32;
    257 	bpdu.cbu_bridgeaddr[2] = cu->cu_rootid >> 24;
    258 	bpdu.cbu_bridgeaddr[3] = cu->cu_rootid >> 16;
    259 	bpdu.cbu_bridgeaddr[4] = cu->cu_rootid >> 8;
    260 	bpdu.cbu_bridgeaddr[5] = cu->cu_rootid >> 0;
    261 
    262 	bpdu.cbu_portid = htons(cu->cu_port_id);
    263 	bpdu.cbu_messageage = htons(cu->cu_message_age);
    264 	bpdu.cbu_maxage = htons(cu->cu_max_age);
    265 	bpdu.cbu_hellotime = htons(cu->cu_hello_time);
    266 	bpdu.cbu_forwarddelay = htons(cu->cu_forward_delay);
    267 
    268 	memcpy(eh->ether_shost, CLLADDR(ifp->if_sadl), ETHER_ADDR_LEN);
    269 	memcpy(eh->ether_dhost, bstp_etheraddr, ETHER_ADDR_LEN);
    270 	eh->ether_type = htons(sizeof(bpdu));
    271 
    272 	memcpy(mtod(m, char *) + sizeof(*eh), &bpdu, sizeof(bpdu));
    273 
    274 	s = splnet();
    275 	bridge_enqueue(sc, ifp, m, 0);
    276 	splx(s);
    277 }
    278 
    279 int
    280 bstp_root_bridge(struct bridge_softc *sc)
    281 {
    282 	return (sc->sc_designated_root == sc->sc_bridge_id);
    283 }
    284 
    285 int
    286 bstp_supersedes_port_info(struct bridge_softc *sc, struct bridge_iflist *bif,
    287     struct bstp_config_unit *cu)
    288 {
    289 	if (cu->cu_rootid < bif->bif_designated_root)
    290 		return (1);
    291 	if (cu->cu_rootid > bif->bif_designated_root)
    292 		return (0);
    293 
    294 	if (cu->cu_root_path_cost < bif->bif_designated_cost)
    295 		return (1);
    296 	if (cu->cu_root_path_cost > bif->bif_designated_cost)
    297 		return (0);
    298 
    299 	if (cu->cu_bridge_id < bif->bif_designated_bridge)
    300 		return (1);
    301 	if (cu->cu_bridge_id > bif->bif_designated_bridge)
    302 		return (0);
    303 
    304 	if (sc->sc_bridge_id != cu->cu_bridge_id)
    305 		return (1);
    306 	if (cu->cu_port_id <= bif->bif_designated_port)
    307 		return (1);
    308 	return (0);
    309 }
    310 
    311 void
    312 bstp_record_config_information(struct bridge_softc *sc,
    313     struct bridge_iflist *bif, struct bstp_config_unit *cu)
    314 {
    315 	bif->bif_designated_root = cu->cu_rootid;
    316 	bif->bif_designated_cost = cu->cu_root_path_cost;
    317 	bif->bif_designated_bridge = cu->cu_bridge_id;
    318 	bif->bif_designated_port = cu->cu_port_id;
    319 	bstp_timer_start(&bif->bif_message_age_timer, cu->cu_message_age);
    320 }
    321 
    322 void
    323 bstp_record_config_timeout_values(struct bridge_softc *sc,
    324     struct bstp_config_unit *config)
    325 {
    326 	sc->sc_max_age = config->cu_max_age;
    327 	sc->sc_hello_time = config->cu_hello_time;
    328 	sc->sc_forward_delay = config->cu_forward_delay;
    329 	sc->sc_topology_change = config->cu_topology_change;
    330 }
    331 
    332 void
    333 bstp_config_bpdu_generation(struct bridge_softc *sc)
    334 {
    335 	struct bridge_iflist *bif;
    336 
    337 	LIST_FOREACH(bif, &sc->sc_iflist, bif_next) {
    338 		if ((bif->bif_flags & IFBIF_STP) == 0)
    339 			continue;
    340 		if (bstp_designated_port(sc, bif) &&
    341 		    (bif->bif_state != BSTP_IFSTATE_DISABLED))
    342 			bstp_transmit_config(sc, bif);
    343 	}
    344 }
    345 
    346 int
    347 bstp_designated_port(struct bridge_softc *sc, struct bridge_iflist *bif)
    348 {
    349 	return ((bif->bif_designated_bridge == sc->sc_bridge_id)
    350 	    && (bif->bif_designated_port == bif->bif_port_id));
    351 }
    352 
    353 void
    354 bstp_transmit_tcn(struct bridge_softc *sc)
    355 {
    356 	struct bstp_tbpdu bpdu;
    357 	struct bridge_iflist *bif = sc->sc_root_port;
    358 	struct ifnet *ifp;
    359 	struct ether_header *eh;
    360 	struct mbuf *m;
    361 	int s;
    362 
    363 	KASSERT(bif != NULL);
    364 	ifp = bif->bif_ifp;
    365 	if ((ifp->if_flags & IFF_RUNNING) == 0)
    366 		return;
    367 
    368 	MGETHDR(m, M_DONTWAIT, MT_DATA);
    369 	if (m == NULL)
    370 		return;
    371 
    372 	m->m_pkthdr.rcvif = ifp;
    373 	m->m_pkthdr.len = sizeof(*eh) + sizeof(bpdu);
    374 	m->m_len = m->m_pkthdr.len;
    375 
    376 	eh = mtod(m, struct ether_header *);
    377 
    378 	memcpy(eh->ether_shost, CLLADDR(ifp->if_sadl), ETHER_ADDR_LEN);
    379 	memcpy(eh->ether_dhost, bstp_etheraddr, ETHER_ADDR_LEN);
    380 	eh->ether_type = htons(sizeof(bpdu));
    381 
    382 	bpdu.tbu_ssap = bpdu.tbu_dsap = LLC_8021D_LSAP;
    383 	bpdu.tbu_ctl = LLC_UI;
    384 	bpdu.tbu_protoid = 0;
    385 	bpdu.tbu_protover = 0;
    386 	bpdu.tbu_bpdutype = BSTP_MSGTYPE_TCN;
    387 
    388 	memcpy(mtod(m, char *) + sizeof(*eh), &bpdu, sizeof(bpdu));
    389 
    390 	s = splnet();
    391 	bridge_enqueue(sc, ifp, m, 0);
    392 	splx(s);
    393 }
    394 
    395 void
    396 bstp_configuration_update(struct bridge_softc *sc)
    397 {
    398 	bstp_root_selection(sc);
    399 	bstp_designated_port_selection(sc);
    400 }
    401 
    402 void
    403 bstp_root_selection(struct bridge_softc *sc)
    404 {
    405 	struct bridge_iflist *root_port = NULL, *bif;
    406 
    407 	LIST_FOREACH(bif, &sc->sc_iflist, bif_next) {
    408 		if ((bif->bif_flags & IFBIF_STP) == 0)
    409 			continue;
    410 		if (bstp_designated_port(sc, bif))
    411 			continue;
    412 		if (bif->bif_state == BSTP_IFSTATE_DISABLED)
    413 			continue;
    414 		if (bif->bif_designated_root >= sc->sc_bridge_id)
    415 			continue;
    416 		if (root_port == NULL)
    417 			goto set_port;
    418 
    419 		if (bif->bif_designated_root < root_port->bif_designated_root)
    420 			goto set_port;
    421 		if (bif->bif_designated_root > root_port->bif_designated_root)
    422 			continue;
    423 
    424 		if ((bif->bif_designated_cost + bif->bif_path_cost) <
    425 		    (root_port->bif_designated_cost + root_port->bif_path_cost))
    426 			goto set_port;
    427 		if ((bif->bif_designated_cost + bif->bif_path_cost) >
    428 		    (root_port->bif_designated_cost + root_port->bif_path_cost))
    429 			continue;
    430 
    431 		if (bif->bif_designated_bridge <
    432 		    root_port->bif_designated_bridge)
    433 			goto set_port;
    434 		if (bif->bif_designated_bridge >
    435 		    root_port->bif_designated_bridge)
    436 			continue;
    437 
    438 		if (bif->bif_designated_port < root_port->bif_designated_port)
    439 			goto set_port;
    440 		if (bif->bif_designated_port > root_port->bif_designated_port)
    441 			continue;
    442 
    443 		if (bif->bif_port_id >= root_port->bif_port_id)
    444 			continue;
    445 set_port:
    446 		root_port = bif;
    447 	}
    448 
    449 	sc->sc_root_port = root_port;
    450 	if (root_port == NULL) {
    451 		sc->sc_designated_root = sc->sc_bridge_id;
    452 		sc->sc_root_path_cost = 0;
    453 	} else {
    454 		sc->sc_designated_root = root_port->bif_designated_root;
    455 		sc->sc_root_path_cost = root_port->bif_designated_cost +
    456 		    root_port->bif_path_cost;
    457 	}
    458 }
    459 
    460 void
    461 bstp_designated_port_selection(struct bridge_softc *sc)
    462 {
    463 	struct bridge_iflist *bif;
    464 
    465 	LIST_FOREACH(bif, &sc->sc_iflist, bif_next) {
    466 		if ((bif->bif_flags & IFBIF_STP) == 0)
    467 			continue;
    468 		if (bstp_designated_port(sc, bif))
    469 			goto designated;
    470 		if (bif->bif_designated_root != sc->sc_designated_root)
    471 			goto designated;
    472 
    473 		if (sc->sc_root_path_cost < bif->bif_designated_cost)
    474 			goto designated;
    475 		if (sc->sc_root_path_cost > bif->bif_designated_cost)
    476 			continue;
    477 
    478 		if (sc->sc_bridge_id < bif->bif_designated_bridge)
    479 			goto designated;
    480 		if (sc->sc_bridge_id > bif->bif_designated_bridge)
    481 			continue;
    482 
    483 		if (bif->bif_port_id > bif->bif_designated_port)
    484 			continue;
    485 designated:
    486 		bstp_become_designated_port(sc, bif);
    487 	}
    488 }
    489 
    490 void
    491 bstp_become_designated_port(struct bridge_softc *sc, struct bridge_iflist *bif)
    492 {
    493 	bif->bif_designated_root = sc->sc_designated_root;
    494 	bif->bif_designated_cost = sc->sc_root_path_cost;
    495 	bif->bif_designated_bridge = sc->sc_bridge_id;
    496 	bif->bif_designated_port = bif->bif_port_id;
    497 }
    498 
    499 void
    500 bstp_port_state_selection(struct bridge_softc *sc)
    501 {
    502 	struct bridge_iflist *bif;
    503 
    504 	LIST_FOREACH(bif, &sc->sc_iflist, bif_next) {
    505 		if ((bif->bif_flags & IFBIF_STP) == 0)
    506 			continue;
    507 		if (bif == sc->sc_root_port) {
    508 			bif->bif_config_pending = 0;
    509 			bif->bif_topology_change_acknowledge = 0;
    510 			bstp_make_forwarding(sc, bif);
    511 		} else if (bstp_designated_port(sc, bif)) {
    512 			bstp_timer_stop(&bif->bif_message_age_timer);
    513 			bstp_make_forwarding(sc, bif);
    514 		} else {
    515 			bif->bif_config_pending = 0;
    516 			bif->bif_topology_change_acknowledge = 0;
    517 			bstp_make_blocking(sc, bif);
    518 		}
    519 	}
    520 }
    521 
    522 void
    523 bstp_make_forwarding(struct bridge_softc *sc,
    524     struct bridge_iflist *bif)
    525 {
    526 	if (bif->bif_state == BSTP_IFSTATE_BLOCKING) {
    527 		bstp_set_port_state(bif, BSTP_IFSTATE_LISTENING);
    528 		bstp_timer_start(&bif->bif_forward_delay_timer, 0);
    529 	}
    530 }
    531 
    532 void
    533 bstp_make_blocking(struct bridge_softc *sc, struct bridge_iflist *bif)
    534 {
    535 	if ((bif->bif_state != BSTP_IFSTATE_DISABLED) &&
    536 	    (bif->bif_state != BSTP_IFSTATE_BLOCKING)) {
    537 		if ((bif->bif_state == BSTP_IFSTATE_FORWARDING) ||
    538 		    (bif->bif_state == BSTP_IFSTATE_LEARNING)) {
    539 			if (bif->bif_change_detection_enabled) {
    540 				bstp_topology_change_detection(sc);
    541 			}
    542 		}
    543 		bstp_set_port_state(bif, BSTP_IFSTATE_BLOCKING);
    544 		bstp_timer_stop(&bif->bif_forward_delay_timer);
    545 	}
    546 }
    547 
    548 void
    549 bstp_set_port_state(struct bridge_iflist *bif, uint8_t state)
    550 {
    551 	bif->bif_state = state;
    552 }
    553 
    554 void
    555 bstp_topology_change_detection(struct bridge_softc *sc)
    556 {
    557 	if (bstp_root_bridge(sc)) {
    558 		sc->sc_topology_change = 1;
    559 		bstp_timer_start(&sc->sc_topology_change_timer, 0);
    560 	} else if (!sc->sc_topology_change_detected) {
    561 		bstp_transmit_tcn(sc);
    562 		bstp_timer_start(&sc->sc_tcn_timer, 0);
    563 	}
    564 	sc->sc_topology_change_detected = 1;
    565 }
    566 
    567 void
    568 bstp_topology_change_acknowledged(struct bridge_softc *sc)
    569 {
    570 	sc->sc_topology_change_detected = 0;
    571 	bstp_timer_stop(&sc->sc_tcn_timer);
    572 }
    573 
    574 void
    575 bstp_acknowledge_topology_change(struct bridge_softc *sc,
    576     struct bridge_iflist *bif)
    577 {
    578 	bif->bif_topology_change_acknowledge = 1;
    579 	bstp_transmit_config(sc, bif);
    580 }
    581 
    582 struct mbuf *
    583 bstp_input(struct bridge_softc *sc, struct bridge_iflist *bif, struct mbuf *m)
    584 {
    585 	struct ether_header *eh;
    586 	struct bstp_tbpdu tpdu;
    587 	struct bstp_cbpdu cpdu;
    588 	struct bstp_config_unit cu;
    589 	struct bstp_tcn_unit tu;
    590 	uint16_t len;
    591 
    592 	eh = mtod(m, struct ether_header *);
    593 
    594 	if ((bif->bif_flags & IFBIF_STP) == 0)
    595 		return (m);
    596 
    597 	len = ntohs(eh->ether_type);
    598 	if (len < sizeof(tpdu))
    599 		goto out;
    600 
    601 	m_adj(m, ETHER_HDR_LEN);
    602 
    603 	if (m->m_pkthdr.len > len)
    604 		m_adj(m, len - m->m_pkthdr.len);
    605 	if (m->m_len < sizeof(tpdu) &&
    606 	    (m = m_pullup(m, sizeof(tpdu))) == NULL)
    607 		goto out;
    608 
    609 	memcpy(&tpdu, mtod(m, void *), sizeof(tpdu));
    610 
    611 	if (tpdu.tbu_dsap != LLC_8021D_LSAP ||
    612 	    tpdu.tbu_ssap != LLC_8021D_LSAP ||
    613 	    tpdu.tbu_ctl != LLC_UI)
    614 		goto out;
    615 	if (tpdu.tbu_protoid != 0 || tpdu.tbu_protover != 0)
    616 		goto out;
    617 
    618 	switch (tpdu.tbu_bpdutype) {
    619 	case BSTP_MSGTYPE_TCN:
    620 		tu.tu_message_type = tpdu.tbu_bpdutype;
    621 		bstp_received_tcn_bpdu(sc, bif, &tu);
    622 		break;
    623 	case BSTP_MSGTYPE_CFG:
    624 		if (m->m_len < sizeof(cpdu) &&
    625 		    (m = m_pullup(m, sizeof(cpdu))) == NULL)
    626 			goto out;
    627 		memcpy(&cpdu, mtod(m, void *), sizeof(cpdu));
    628 
    629 		cu.cu_rootid =
    630 		    (((uint64_t)ntohs(cpdu.cbu_rootpri)) << 48) |
    631 		    (((uint64_t)cpdu.cbu_rootaddr[0]) << 40) |
    632 		    (((uint64_t)cpdu.cbu_rootaddr[1]) << 32) |
    633 		    (((uint64_t)cpdu.cbu_rootaddr[2]) << 24) |
    634 		    (((uint64_t)cpdu.cbu_rootaddr[3]) << 16) |
    635 		    (((uint64_t)cpdu.cbu_rootaddr[4]) << 8) |
    636 		    (((uint64_t)cpdu.cbu_rootaddr[5]) << 0);
    637 
    638 		cu.cu_bridge_id =
    639 		    (((uint64_t)ntohs(cpdu.cbu_bridgepri)) << 48) |
    640 		    (((uint64_t)cpdu.cbu_bridgeaddr[0]) << 40) |
    641 		    (((uint64_t)cpdu.cbu_bridgeaddr[1]) << 32) |
    642 		    (((uint64_t)cpdu.cbu_bridgeaddr[2]) << 24) |
    643 		    (((uint64_t)cpdu.cbu_bridgeaddr[3]) << 16) |
    644 		    (((uint64_t)cpdu.cbu_bridgeaddr[4]) << 8) |
    645 		    (((uint64_t)cpdu.cbu_bridgeaddr[5]) << 0);
    646 
    647 		cu.cu_root_path_cost = ntohl(cpdu.cbu_rootpathcost);
    648 		cu.cu_message_age = ntohs(cpdu.cbu_messageage);
    649 		cu.cu_max_age = ntohs(cpdu.cbu_maxage);
    650 		cu.cu_hello_time = ntohs(cpdu.cbu_hellotime);
    651 		cu.cu_forward_delay = ntohs(cpdu.cbu_forwarddelay);
    652 		cu.cu_port_id = ntohs(cpdu.cbu_portid);
    653 		cu.cu_message_type = cpdu.cbu_bpdutype;
    654 		cu.cu_topology_change_acknowledgment =
    655 		    (cpdu.cbu_flags & BSTP_FLAG_TCA) ? 1 : 0;
    656 		cu.cu_topology_change =
    657 		    (cpdu.cbu_flags & BSTP_FLAG_TC) ? 1 : 0;
    658 		bstp_received_config_bpdu(sc, bif, &cu);
    659 		break;
    660 	default:
    661 		goto out;
    662 	}
    663 
    664  out:
    665 	if (m)
    666 		m_freem(m);
    667 	return (NULL);
    668 }
    669 
    670 void
    671 bstp_received_config_bpdu(struct bridge_softc *sc, struct bridge_iflist *bif,
    672     struct bstp_config_unit *cu)
    673 {
    674 	int root;
    675 
    676 	root = bstp_root_bridge(sc);
    677 
    678 	if (bif->bif_state != BSTP_IFSTATE_DISABLED) {
    679 		if (bstp_supersedes_port_info(sc, bif, cu)) {
    680 			bstp_record_config_information(sc, bif, cu);
    681 			bstp_configuration_update(sc);
    682 			bstp_port_state_selection(sc);
    683 
    684 			if ((bstp_root_bridge(sc) == 0) && root) {
    685 				bstp_timer_stop(&sc->sc_hello_timer);
    686 
    687 				if (sc->sc_topology_change_detected) {
    688 					bstp_timer_stop(
    689 					    &sc->sc_topology_change_timer);
    690 					bstp_transmit_tcn(sc);
    691 					bstp_timer_start(&sc->sc_tcn_timer, 0);
    692 				}
    693 			}
    694 
    695 			if (bif == sc->sc_root_port) {
    696 				bstp_record_config_timeout_values(sc, cu);
    697 				bstp_config_bpdu_generation(sc);
    698 
    699 				if (cu->cu_topology_change_acknowledgment)
    700 					bstp_topology_change_acknowledged(sc);
    701 			}
    702 		} else if (bstp_designated_port(sc, bif))
    703 			bstp_transmit_config(sc, bif);
    704 	}
    705 }
    706 
    707 void
    708 bstp_received_tcn_bpdu(struct bridge_softc *sc, struct bridge_iflist *bif,
    709     struct bstp_tcn_unit *tcn)
    710 {
    711 	if (bif->bif_state != BSTP_IFSTATE_DISABLED &&
    712 	    bstp_designated_port(sc, bif)) {
    713 		bstp_topology_change_detection(sc);
    714 		bstp_acknowledge_topology_change(sc, bif);
    715 	}
    716 }
    717 
    718 void
    719 bstp_hello_timer_expiry(struct bridge_softc *sc)
    720 {
    721 	bstp_config_bpdu_generation(sc);
    722 	bstp_timer_start(&sc->sc_hello_timer, 0);
    723 }
    724 
    725 void
    726 bstp_message_age_timer_expiry(struct bridge_softc *sc,
    727     struct bridge_iflist *bif)
    728 {
    729 	int root;
    730 
    731 	root = bstp_root_bridge(sc);
    732 	bstp_become_designated_port(sc, bif);
    733 	bstp_configuration_update(sc);
    734 	bstp_port_state_selection(sc);
    735 
    736 	if ((bstp_root_bridge(sc)) && (root == 0)) {
    737 		sc->sc_max_age = sc->sc_bridge_max_age;
    738 		sc->sc_hello_time = sc->sc_bridge_hello_time;
    739 		sc->sc_forward_delay = sc->sc_bridge_forward_delay;
    740 
    741 		bstp_topology_change_detection(sc);
    742 		bstp_timer_stop(&sc->sc_tcn_timer);
    743 		bstp_config_bpdu_generation(sc);
    744 		bstp_timer_start(&sc->sc_hello_timer, 0);
    745 	}
    746 }
    747 
    748 void
    749 bstp_forward_delay_timer_expiry(struct bridge_softc *sc,
    750     struct bridge_iflist *bif)
    751 {
    752 	if (bif->bif_state == BSTP_IFSTATE_LISTENING) {
    753 		bstp_set_port_state(bif, BSTP_IFSTATE_LEARNING);
    754 		bstp_timer_start(&bif->bif_forward_delay_timer, 0);
    755 	} else if (bif->bif_state == BSTP_IFSTATE_LEARNING) {
    756 		bstp_set_port_state(bif, BSTP_IFSTATE_FORWARDING);
    757 		if (bstp_designated_for_some_port(sc) &&
    758 		    bif->bif_change_detection_enabled)
    759 			bstp_topology_change_detection(sc);
    760 	}
    761 }
    762 
    763 int
    764 bstp_designated_for_some_port(struct bridge_softc *sc)
    765 {
    766 
    767 	struct bridge_iflist *bif;
    768 
    769 	LIST_FOREACH(bif, &sc->sc_iflist, bif_next) {
    770 		if ((bif->bif_flags & IFBIF_STP) == 0)
    771 			continue;
    772 		if (bif->bif_designated_bridge == sc->sc_bridge_id)
    773 			return (1);
    774 	}
    775 	return (0);
    776 }
    777 
    778 void
    779 bstp_tcn_timer_expiry(struct bridge_softc *sc)
    780 {
    781 	bstp_transmit_tcn(sc);
    782 	bstp_timer_start(&sc->sc_tcn_timer, 0);
    783 }
    784 
    785 void
    786 bstp_topology_change_timer_expiry(struct bridge_softc *sc)
    787 {
    788 	sc->sc_topology_change_detected = 0;
    789 	sc->sc_topology_change = 0;
    790 }
    791 
    792 void
    793 bstp_hold_timer_expiry(struct bridge_softc *sc, struct bridge_iflist *bif)
    794 {
    795 	if (bif->bif_config_pending)
    796 		bstp_transmit_config(sc, bif);
    797 }
    798 
    799 void
    800 bstp_initialization(struct bridge_softc *sc)
    801 {
    802 	struct bridge_iflist *bif, *mif;
    803 
    804 	mif = NULL;
    805 	LIST_FOREACH(bif, &sc->sc_iflist, bif_next) {
    806 		if ((bif->bif_flags & IFBIF_STP) == 0)
    807 			continue;
    808 		if (bif->bif_ifp->if_type != IFT_ETHER)
    809 			continue;
    810 		bif->bif_port_id = (bif->bif_priority << 8) |
    811 		    (bif->bif_ifp->if_index & 0xff);
    812 
    813 		if (mif == NULL) {
    814 			mif = bif;
    815 			continue;
    816 		}
    817 		if (memcmp(CLLADDR(bif->bif_ifp->if_sadl),
    818 		    CLLADDR(mif->bif_ifp->if_sadl), ETHER_ADDR_LEN) < 0) {
    819 			mif = bif;
    820 			continue;
    821 		}
    822 	}
    823 	if (mif == NULL) {
    824 		bstp_stop(sc);
    825 		return;
    826 	}
    827 
    828 	sc->sc_bridge_id =
    829 	    (((uint64_t)sc->sc_bridge_priority) << 48) |
    830 	    (((uint64_t)(uint8_t)CLLADDR(mif->bif_ifp->if_sadl)[0]) << 40) |
    831 	    (((uint64_t)(uint8_t)CLLADDR(mif->bif_ifp->if_sadl)[1]) << 32) |
    832 	    (((uint64_t)(uint8_t)CLLADDR(mif->bif_ifp->if_sadl)[2]) << 24) |
    833 	    (((uint64_t)(uint8_t)CLLADDR(mif->bif_ifp->if_sadl)[3]) << 16) |
    834 	    (((uint64_t)(uint8_t)CLLADDR(mif->bif_ifp->if_sadl)[4]) << 8) |
    835 	    (((uint64_t)(uint8_t)CLLADDR(mif->bif_ifp->if_sadl)[5]) << 0);
    836 
    837 	sc->sc_designated_root = sc->sc_bridge_id;
    838 	sc->sc_root_path_cost = 0;
    839 	sc->sc_root_port = NULL;
    840 
    841 	sc->sc_max_age = sc->sc_bridge_max_age;
    842 	sc->sc_hello_time = sc->sc_bridge_hello_time;
    843 	sc->sc_forward_delay = sc->sc_bridge_forward_delay;
    844 	sc->sc_topology_change_detected = 0;
    845 	sc->sc_topology_change = 0;
    846 	bstp_timer_stop(&sc->sc_tcn_timer);
    847 	bstp_timer_stop(&sc->sc_topology_change_timer);
    848 
    849 	if (callout_pending(&sc->sc_bstpcallout) == 0)
    850 		callout_reset(&sc->sc_bstpcallout, hz,
    851 		    bstp_tick, sc);
    852 
    853 	LIST_FOREACH(bif, &sc->sc_iflist, bif_next) {
    854 		if (bif->bif_flags & IFBIF_STP)
    855 			bstp_enable_port(sc, bif);
    856 		else
    857 			bstp_disable_port(sc, bif);
    858 	}
    859 
    860 	bstp_port_state_selection(sc);
    861 	bstp_config_bpdu_generation(sc);
    862 	bstp_timer_start(&sc->sc_hello_timer, 0);
    863 }
    864 
    865 void
    866 bstp_stop(struct bridge_softc *sc)
    867 {
    868 	struct bridge_iflist *bif;
    869 
    870 	LIST_FOREACH(bif, &sc->sc_iflist, bif_next) {
    871 		bstp_set_port_state(bif, BSTP_IFSTATE_DISABLED);
    872 		bstp_timer_stop(&bif->bif_hold_timer);
    873 		bstp_timer_stop(&bif->bif_message_age_timer);
    874 		bstp_timer_stop(&bif->bif_forward_delay_timer);
    875 	}
    876 
    877 	callout_stop(&sc->sc_bstpcallout);
    878 
    879 	bstp_timer_stop(&sc->sc_topology_change_timer);
    880 	bstp_timer_stop(&sc->sc_tcn_timer);
    881 	bstp_timer_stop(&sc->sc_hello_timer);
    882 
    883 }
    884 
    885 void
    886 bstp_initialize_port(struct bridge_softc *sc, struct bridge_iflist *bif)
    887 {
    888 	bstp_become_designated_port(sc, bif);
    889 	bstp_set_port_state(bif, BSTP_IFSTATE_BLOCKING);
    890 	bif->bif_topology_change_acknowledge = 0;
    891 	bif->bif_config_pending = 0;
    892 	bif->bif_change_detection_enabled = 1;
    893 	bstp_timer_stop(&bif->bif_message_age_timer);
    894 	bstp_timer_stop(&bif->bif_forward_delay_timer);
    895 	bstp_timer_stop(&bif->bif_hold_timer);
    896 }
    897 
    898 void
    899 bstp_enable_port(struct bridge_softc *sc, struct bridge_iflist *bif)
    900 {
    901 	bstp_initialize_port(sc, bif);
    902 	bstp_port_state_selection(sc);
    903 }
    904 
    905 void
    906 bstp_disable_port(struct bridge_softc *sc, struct bridge_iflist *bif)
    907 {
    908 	int root;
    909 
    910 	root = bstp_root_bridge(sc);
    911 	bstp_become_designated_port(sc, bif);
    912 	bstp_set_port_state(bif, BSTP_IFSTATE_DISABLED);
    913 	bif->bif_topology_change_acknowledge = 0;
    914 	bif->bif_config_pending = 0;
    915 	bstp_timer_stop(&bif->bif_message_age_timer);
    916 	bstp_timer_stop(&bif->bif_forward_delay_timer);
    917 	bstp_configuration_update(sc);
    918 	bstp_port_state_selection(sc);
    919 
    920 	if (bstp_root_bridge(sc) && (root == 0)) {
    921 		sc->sc_max_age = sc->sc_bridge_max_age;
    922 		sc->sc_hello_time = sc->sc_bridge_hello_time;
    923 		sc->sc_forward_delay = sc->sc_bridge_forward_delay;
    924 
    925 		bstp_topology_change_detection(sc);
    926 		bstp_timer_stop(&sc->sc_tcn_timer);
    927 		bstp_config_bpdu_generation(sc);
    928 		bstp_timer_start(&sc->sc_hello_timer, 0);
    929 	}
    930 }
    931 
    932 void
    933 bstp_set_bridge_priority(struct bridge_softc *sc, uint64_t new_bridge_id)
    934 {
    935 	struct bridge_iflist *bif;
    936 	int root;
    937 
    938 	root = bstp_root_bridge(sc);
    939 
    940 	LIST_FOREACH(bif, &sc->sc_iflist, bif_next) {
    941 		if ((bif->bif_flags & IFBIF_STP) == 0)
    942 			continue;
    943 		if (bstp_designated_port(sc, bif))
    944 			bif->bif_designated_bridge = new_bridge_id;
    945 	}
    946 
    947 	sc->sc_bridge_id = new_bridge_id;
    948 
    949 	bstp_configuration_update(sc);
    950 	bstp_port_state_selection(sc);
    951 
    952 	if (bstp_root_bridge(sc) && (root == 0)) {
    953 		sc->sc_max_age = sc->sc_bridge_max_age;
    954 		sc->sc_hello_time = sc->sc_bridge_hello_time;
    955 		sc->sc_forward_delay = sc->sc_bridge_forward_delay;
    956 
    957 		bstp_topology_change_detection(sc);
    958 		bstp_timer_stop(&sc->sc_tcn_timer);
    959 		bstp_config_bpdu_generation(sc);
    960 		bstp_timer_start(&sc->sc_hello_timer, 0);
    961 	}
    962 }
    963 
    964 void
    965 bstp_set_port_priority(struct bridge_softc *sc, struct bridge_iflist *bif,
    966     uint16_t new_port_id)
    967 {
    968 	if (bstp_designated_port(sc, bif))
    969 		bif->bif_designated_port = new_port_id;
    970 
    971 	bif->bif_port_id = new_port_id;
    972 
    973 	if ((sc->sc_bridge_id == bif->bif_designated_bridge) &&
    974 	    (bif->bif_port_id < bif->bif_designated_port)) {
    975 		bstp_become_designated_port(sc, bif);
    976 		bstp_port_state_selection(sc);
    977 	}
    978 }
    979 
    980 void
    981 bstp_set_path_cost(struct bridge_softc *sc, struct bridge_iflist *bif,
    982     uint32_t path_cost)
    983 {
    984 	bif->bif_path_cost = path_cost;
    985 	bstp_configuration_update(sc);
    986 	bstp_port_state_selection(sc);
    987 }
    988 
    989 void
    990 bstp_enable_change_detection(struct bridge_iflist *bif)
    991 {
    992 	bif->bif_change_detection_enabled = 1;
    993 }
    994 
    995 void
    996 bstp_disable_change_detection(struct bridge_iflist *bif)
    997 {
    998 	bif->bif_change_detection_enabled = 0;
    999 }
   1000 
   1001 void
   1002 bstp_ifupdstatus(struct bridge_softc *sc, struct bridge_iflist *bif)
   1003 {
   1004 	struct ifnet *ifp = bif->bif_ifp;
   1005 
   1006 	if (ifp->if_flags & IFF_UP) {
   1007 	 	switch (ifp->if_link_state) {
   1008 		case LINK_STATE_UNKNOWN:
   1009 			/*
   1010 			 * Just enable the port if the link state is
   1011 			 * unknown.
   1012 			 */
   1013 			if (bif->bif_state == BSTP_IFSTATE_DISABLED)
   1014 				bstp_enable_port(sc, bif);
   1015 			break;
   1016 
   1017 		case LINK_STATE_UP:
   1018 			if (bif->bif_state == BSTP_IFSTATE_DISABLED)
   1019 				bstp_enable_port(sc, bif);
   1020 			break;
   1021 
   1022 		case LINK_STATE_DOWN:
   1023 			if (bif->bif_state != BSTP_IFSTATE_DISABLED)
   1024 				bstp_disable_port(sc, bif);
   1025 			break;
   1026 		}
   1027 		return;
   1028 	}
   1029 
   1030 	if (bif->bif_state != BSTP_IFSTATE_DISABLED)
   1031 		bstp_disable_port(sc, bif);
   1032 }
   1033 
   1034 void
   1035 bstp_tick(void *arg)
   1036 {
   1037 	struct bridge_softc *sc = arg;
   1038 	struct bridge_iflist *bif;
   1039 	int s;
   1040 
   1041 	s = splnet();
   1042 
   1043 	LIST_FOREACH(bif, &sc->sc_iflist, bif_next) {
   1044 		if ((bif->bif_flags & IFBIF_STP) == 0)
   1045 			continue;
   1046 		/*
   1047 		 * XXX This can cause a lag in "link does away"
   1048 		 * XXX and "spanning tree gets updated".  We need
   1049 		 * XXX come sort of callback from the link state
   1050 		 * XXX update code to kick spanning tree.
   1051 		 * XXX --thorpej (at) NetBSD.org
   1052 		 */
   1053 		bstp_ifupdstatus(sc, bif);
   1054 	}
   1055 
   1056 	if (bstp_timer_expired(&sc->sc_hello_timer, sc->sc_hello_time))
   1057 		bstp_hello_timer_expiry(sc);
   1058 
   1059 	if (bstp_timer_expired(&sc->sc_tcn_timer, sc->sc_bridge_hello_time))
   1060 		bstp_tcn_timer_expiry(sc);
   1061 
   1062 	if (bstp_timer_expired(&sc->sc_topology_change_timer,
   1063 	    sc->sc_topology_change_time))
   1064 		bstp_topology_change_timer_expiry(sc);
   1065 
   1066 	LIST_FOREACH(bif, &sc->sc_iflist, bif_next) {
   1067 		if ((bif->bif_flags & IFBIF_STP) == 0)
   1068 			continue;
   1069 		if (bstp_timer_expired(&bif->bif_message_age_timer,
   1070 		    sc->sc_max_age))
   1071 			bstp_message_age_timer_expiry(sc, bif);
   1072 	}
   1073 
   1074 	LIST_FOREACH(bif, &sc->sc_iflist, bif_next) {
   1075 		if ((bif->bif_flags & IFBIF_STP) == 0)
   1076 			continue;
   1077 		if (bstp_timer_expired(&bif->bif_forward_delay_timer,
   1078 		    sc->sc_forward_delay))
   1079 			bstp_forward_delay_timer_expiry(sc, bif);
   1080 
   1081 		if (bstp_timer_expired(&bif->bif_hold_timer,
   1082 		    sc->sc_hold_time))
   1083 			bstp_hold_timer_expiry(sc, bif);
   1084 	}
   1085 
   1086 	if (sc->sc_if.if_flags & IFF_RUNNING)
   1087 		callout_reset(&sc->sc_bstpcallout, hz, bstp_tick, sc);
   1088 
   1089 	splx(s);
   1090 }
   1091 
   1092 void
   1093 bstp_timer_start(struct bridge_timer *t, uint16_t v)
   1094 {
   1095 	t->value = v;
   1096 	t->active = 1;
   1097 }
   1098 
   1099 void
   1100 bstp_timer_stop(struct bridge_timer *t)
   1101 {
   1102 	t->value = 0;
   1103 	t->active = 0;
   1104 }
   1105 
   1106 int
   1107 bstp_timer_expired(struct bridge_timer *t, uint16_t v)
   1108 {
   1109 	if (t->active == 0)
   1110 		return (0);
   1111 	t->value += BSTP_TICK_VAL;
   1112 	if (t->value >= v) {
   1113 		bstp_timer_stop(t);
   1114 		return (1);
   1115 	}
   1116 	return (0);
   1117 
   1118 }
   1119