xref: /netbsd-src/sys/net/agr/ieee8023ad_lacp.c (revision 7fa608457b817eca6e0977b37f758ae064f3c99c)
1 /*	$NetBSD: ieee8023ad_lacp.c,v 1.8 2007/08/26 22:59:09 dyoung Exp $	*/
2 
3 /*-
4  * Copyright (c)2005 YAMAMOTO Takashi,
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  *
16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
17  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
20  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26  * SUCH DAMAGE.
27  */
28 
29 #include <sys/cdefs.h>
30 __KERNEL_RCSID(0, "$NetBSD: ieee8023ad_lacp.c,v 1.8 2007/08/26 22:59:09 dyoung Exp $");
31 
32 #include <sys/param.h>
33 #include <sys/callout.h>
34 #include <sys/mbuf.h>
35 #include <sys/systm.h>
36 #include <sys/malloc.h>
37 #include <sys/kernel.h> /* hz */
38 
39 #include <net/if.h>
40 #include <net/if_dl.h>
41 #include <net/if_ether.h>
42 #include <net/if_media.h>
43 
44 #include <net/agr/if_agrvar_impl.h>
45 #include <net/agr/if_agrsubr.h>
46 #include <net/agr/ieee8023_slowprotocols.h>
47 #include <net/agr/ieee8023_tlv.h>
48 #include <net/agr/ieee8023ad.h>
49 #include <net/agr/ieee8023ad_lacp.h>
50 #include <net/agr/ieee8023ad_lacp_impl.h>
51 #include <net/agr/ieee8023ad_impl.h>
52 #include <net/agr/ieee8023ad_lacp_sm.h>
53 #include <net/agr/ieee8023ad_lacp_debug.h>
54 
55 static void lacp_fill_actorinfo(struct agr_port *, struct lacp_peerinfo *);
56 
57 static uint64_t lacp_aggregator_bandwidth(struct lacp_aggregator *);
58 static void lacp_suppress_distributing(struct lacp_softc *,
59     struct lacp_aggregator *);
60 static void lacp_transit_expire(void *);
61 static void lacp_select_active_aggregator(struct lacp_softc *);
62 static uint16_t lacp_compose_key(struct lacp_port *);
63 
64 /*
65  * actor system priority and port priority.
66  * XXX should be configurable.
67  */
68 
69 #define	LACP_SYSTEM_PRIO	0x8000
70 #define	LACP_PORT_PRIO		0x8000
71 
72 static const struct tlv_template lacp_info_tlv_template[] = {
73 	{ LACP_TYPE_ACTORINFO,
74 	    sizeof(struct tlvhdr) + sizeof(struct lacp_peerinfo) },
75 	{ LACP_TYPE_PARTNERINFO,
76 	    sizeof(struct tlvhdr) + sizeof(struct lacp_peerinfo) },
77 	{ LACP_TYPE_COLLECTORINFO,
78 	    sizeof(struct tlvhdr) + sizeof(struct lacp_collectorinfo) },
79 	{ 0, 0 },
80 };
81 
82 /*
83  * ieee8023ad_lacp_input: process lacpdu
84  *
85  * => called from ether_input.  (ie. at IPL_NET)
86  *
87  * XXX is it better to defer processing to lower IPL?
88  * XXX anyway input rate should be very low...
89  */
90 
91 int
92 ieee8023ad_lacp_input(struct ifnet *ifp, struct mbuf *m)
93 {
94 	struct lacpdu *du;
95 	struct agr_softc *sc;
96 	struct agr_port *port;
97 	struct lacp_port *lp;
98 	int error = 0;
99 
100 	port = ifp->if_agrprivate; /* XXX race with agr_remport. */
101 	if (__predict_false(port->port_flags & AGRPORT_DETACHING)) {
102 		goto bad;
103 	}
104 	sc = AGR_SC_FROM_PORT(port);
105 	KASSERT(port);
106 
107 	if (m->m_pkthdr.len != sizeof(*du)) {
108 		goto bad;
109 	}
110 
111 	if ((m->m_flags & M_MCAST) == 0) {
112 		goto bad;
113 	}
114 
115 	if (m->m_len < sizeof(*du)) {
116 		m = m_pullup(m, sizeof(*du));
117 		if (m == NULL) {
118 			return ENOMEM;
119 		}
120 	}
121 
122 	du = mtod(m, struct lacpdu *);
123 
124 	if (memcmp(&du->ldu_eh.ether_dhost,
125 	    &ethermulticastaddr_slowprotocols, ETHER_ADDR_LEN)) {
126 		goto bad;
127 	}
128 
129 	KASSERT(du->ldu_sph.sph_subtype == SLOWPROTOCOLS_SUBTYPE_LACP);
130 
131 	/*
132 	 * ignore the version for compatibility with
133 	 * the future protocol revisions.
134 	 */
135 
136 #if 0
137 	if (du->ldu_sph.sph_version != 1) {
138 		goto bad;
139 	}
140 #endif
141 
142 	/*
143 	 * ignore tlv types for compatibility with
144 	 * the future protocol revisions.
145 	 */
146 
147 	if (tlv_check(du, sizeof(*du), &du->ldu_tlv_actor,
148 	    lacp_info_tlv_template, false)) {
149 		goto bad;
150 	}
151 
152 	AGR_LOCK(sc);
153 	lp = LACP_PORT(port);
154 
155 #if defined(LACP_DEBUG)
156 	if (lacpdebug) {
157 		LACP_DPRINTF((lp, "lacpdu receive\n"));
158 		lacp_dump_lacpdu(du);
159 	}
160 #endif /* defined(LACP_DEBUG) */
161 	lacp_sm_rx(lp, du);
162 
163 	AGR_UNLOCK(sc);
164 
165 	m_freem(m);
166 
167 	return error;
168 
169 bad:
170 	m_freem(m);
171 	return EINVAL;
172 }
173 
174 static void
175 lacp_fill_actorinfo(struct agr_port *port, struct lacp_peerinfo *info)
176 {
177 	struct lacp_port *lp = LACP_PORT(port);
178 
179 	info->lip_systemid.lsi_prio = htobe16(LACP_SYSTEM_PRIO);
180 	memcpy(&info->lip_systemid.lsi_mac,
181 	    CLLADDR(port->port_ifp->if_sadl), ETHER_ADDR_LEN);
182 	info->lip_portid.lpi_prio = htobe16(LACP_PORT_PRIO);
183 	info->lip_portid.lpi_portno = htobe16(port->port_ifp->if_index);
184 	info->lip_state = lp->lp_state;
185 }
186 
187 int
188 lacp_xmit_lacpdu(struct lacp_port *lp)
189 {
190 	struct agr_port *port = lp->lp_agrport;
191 	struct mbuf *m;
192 	struct lacpdu *du;
193 	int error;
194 
195 	KDASSERT(MHLEN >= sizeof(*du));
196 
197 	m = m_gethdr(M_DONTWAIT, MT_DATA);
198 	if (m == NULL) {
199 		return ENOMEM;
200 	}
201 	m->m_len = m->m_pkthdr.len = sizeof(*du);
202 
203 	du = mtod(m, struct lacpdu *);
204 	memset(du, 0, sizeof(*du));
205 
206 	memcpy(&du->ldu_eh.ether_dhost, ethermulticastaddr_slowprotocols,
207 	    ETHER_ADDR_LEN);
208 	memcpy(&du->ldu_eh.ether_shost, &port->port_origlladdr, ETHER_ADDR_LEN);
209 	du->ldu_eh.ether_type = htobe16(ETHERTYPE_SLOWPROTOCOLS);
210 
211 	du->ldu_sph.sph_subtype = SLOWPROTOCOLS_SUBTYPE_LACP;
212 	du->ldu_sph.sph_version = 1;
213 
214 	TLV_SET(&du->ldu_tlv_actor, LACP_TYPE_ACTORINFO, sizeof(du->ldu_actor));
215 	du->ldu_actor = lp->lp_actor;
216 
217 	TLV_SET(&du->ldu_tlv_partner, LACP_TYPE_PARTNERINFO,
218 	    sizeof(du->ldu_partner));
219 	du->ldu_partner = lp->lp_partner;
220 
221 	TLV_SET(&du->ldu_tlv_collector, LACP_TYPE_COLLECTORINFO,
222 	    sizeof(du->ldu_collector));
223 	du->ldu_collector.lci_maxdelay = 0;
224 
225 #if defined(LACP_DEBUG)
226 	if (lacpdebug) {
227 		LACP_DPRINTF((lp, "lacpdu transmit\n"));
228 		lacp_dump_lacpdu(du);
229 	}
230 #endif /* defined(LACP_DEBUG) */
231 
232 	m->m_flags |= M_MCAST;
233 
234 	/*
235 	 * XXX should use higher priority queue.
236 	 * otherwise network congestion can break aggregation.
237 	 */
238 
239 	error = agr_xmit_frame(port->port_ifp, m);
240 	return error;
241 }
242 
243 void
244 ieee8023ad_lacp_portstate(struct agr_port *port)
245 {
246 	struct lacp_port *lp = LACP_PORT(port);
247 	u_int media = port->port_media;
248 	uint8_t old_state;
249 	uint16_t old_key;
250 
251 	AGR_ASSERT_LOCKED(AGR_SC_FROM_PORT(port));
252 
253 	LACP_DPRINTF((lp, "media changed 0x%x -> 0x%x\n", lp->lp_media, media));
254 
255 	old_state = lp->lp_state;
256 	old_key = lp->lp_key;
257 
258 	lp->lp_media = media;
259 	if ((media & IFM_HDX) != 0) {
260 		lp->lp_state &= ~LACP_STATE_AGGREGATION;
261 	} else {
262 		lp->lp_state |= LACP_STATE_AGGREGATION;
263 	}
264 	lp->lp_key = lacp_compose_key(lp);
265 
266 	if (old_state != lp->lp_state || old_key != lp->lp_key) {
267 		LACP_DPRINTF((lp, "-> UNSELECTED\n"));
268 		lp->lp_selected = LACP_UNSELECTED;
269 	}
270 }
271 
272 void
273 ieee8023ad_lacp_porttick(struct agr_softc *sc, struct agr_port *port)
274 {
275 	struct lacp_port *lp = LACP_PORT(port);
276 
277 	AGR_ASSERT_LOCKED(sc);
278 
279 	lacp_run_timers(lp);
280 
281 	lacp_select(lp);
282 	lacp_sm_mux(lp);
283 	lacp_sm_tx(lp);
284 	lacp_sm_ptx_tx_schedule(lp);
285 }
286 
287 void
288 lacp_portinit(struct agr_port *port)
289 {
290 	struct lacp_port *lp = LACP_PORT(port);
291 	bool active = true; /* XXX should be configurable */
292 	bool fast = false; /* XXX should be configurable */
293 
294 	lp->lp_agrport = port;
295 	lacp_fill_actorinfo(port, &lp->lp_actor);
296 	lp->lp_state =
297 	    (active ? LACP_STATE_ACTIVITY : 0) |
298 	    (fast ? LACP_STATE_TIMEOUT : 0);
299 	lp->lp_aggregator = NULL;
300 	lp->lp_media = port->port_media; /* XXX */
301 	lp->lp_key = lacp_compose_key(lp);
302 	lacp_sm_rx_set_expired(lp);
303 }
304 
305 void
306 lacp_portfini(struct agr_port *port)
307 {
308 	struct lacp_port *lp = LACP_PORT(port);
309 	struct lacp_aggregator *la = lp->lp_aggregator;
310 	int i;
311 
312 	LACP_DPRINTF((lp, "portfini\n"));
313 
314 	for (i = 0; i < LACP_NTIMER; i++) {
315 		LACP_TIMER_DISARM(lp, i);
316 	}
317 
318 	if (la == NULL) {
319 		return;
320 	}
321 
322 	lacp_disable_distributing(lp);
323 	lacp_unselect(lp);
324 }
325 
326 /* -------------------- */
327 void
328 lacp_disable_collecting(struct lacp_port *lp)
329 {
330 	struct agr_port *port = lp->lp_agrport;
331 
332 	lp->lp_state &= ~LACP_STATE_COLLECTING;
333 	port->port_flags &= ~AGRPORT_COLLECTING;
334 }
335 
336 void
337 lacp_enable_collecting(struct lacp_port *lp)
338 {
339 	struct agr_port *port = lp->lp_agrport;
340 
341 	lp->lp_state |= LACP_STATE_COLLECTING;
342 	port->port_flags |= AGRPORT_COLLECTING;
343 }
344 
345 void
346 lacp_disable_distributing(struct lacp_port *lp)
347 {
348 	struct agr_port *port = lp->lp_agrport;
349 	struct lacp_aggregator *la = lp->lp_aggregator;
350 	struct lacp_softc *lsc = LACP_SOFTC(AGR_SC_FROM_PORT(port));
351 #if defined(LACP_DEBUG)
352 	char buf[LACP_LAGIDSTR_MAX+1];
353 #endif /* defined(LACP_DEBUG) */
354 
355 	if ((lp->lp_state & LACP_STATE_DISTRIBUTING) == 0) {
356 		return;
357 	}
358 
359 	KASSERT(la);
360 	KASSERT(!TAILQ_EMPTY(&la->la_ports));
361 	KASSERT(la->la_nports > 0);
362 	KASSERT(la->la_refcnt >= la->la_nports);
363 
364 	LACP_DPRINTF((lp, "disable distributing on aggregator %s, "
365 	    "nports %d -> %d\n",
366 	    lacp_format_lagid_aggregator(la, buf, sizeof(buf)),
367 	    la->la_nports, la->la_nports - 1));
368 
369 	TAILQ_REMOVE(&la->la_ports, lp, lp_dist_q);
370 	la->la_nports--;
371 
372 	lacp_suppress_distributing(lsc, la);
373 
374 	lp->lp_state &= ~LACP_STATE_DISTRIBUTING;
375 	port->port_flags &= ~AGRPORT_DISTRIBUTING;
376 
377 	if (lsc->lsc_active_aggregator == la) {
378 		lacp_select_active_aggregator(lsc);
379 	}
380 }
381 
382 void
383 lacp_enable_distributing(struct lacp_port *lp)
384 {
385 	struct agr_port *port = lp->lp_agrport;
386 	struct lacp_aggregator *la = lp->lp_aggregator;
387 	struct lacp_softc *lsc = LACP_SOFTC(AGR_SC_FROM_PORT(port));
388 #if defined(LACP_DEBUG)
389 	char buf[LACP_LAGIDSTR_MAX+1];
390 #endif /* defined(LACP_DEBUG) */
391 
392 	if ((lp->lp_state & LACP_STATE_DISTRIBUTING) != 0) {
393 		return;
394 	}
395 
396 	KASSERT(la);
397 
398 	LACP_DPRINTF((lp, "enable distributing on aggregator %s, "
399 	    "nports %d -> %d\n",
400 	    lacp_format_lagid_aggregator(la, buf, sizeof(buf)),
401 	    la->la_nports, la->la_nports + 1));
402 
403 	KASSERT(la->la_refcnt > la->la_nports);
404 	TAILQ_INSERT_HEAD(&la->la_ports, lp, lp_dist_q);
405 	la->la_nports++;
406 
407 	lacp_suppress_distributing(lsc, la);
408 
409 	lp->lp_state |= LACP_STATE_DISTRIBUTING;
410 	port->port_flags |= AGRPORT_DISTRIBUTING;
411 
412 	if (lsc->lsc_active_aggregator != la) {
413 		lacp_select_active_aggregator(lsc);
414 	}
415 }
416 
417 static void
418 lacp_transit_expire(void *vp)
419 {
420 	struct agr_softc *sc = vp;
421 	struct lacp_softc *lsc = LACP_SOFTC(sc);
422 
423 	AGR_LOCK(sc);
424 	LACP_DPRINTF((NULL, "%s\n", __func__));
425 	lsc->lsc_suppress_distributing = false;
426 	AGR_UNLOCK(sc);
427 }
428 
429 /* -------------------- */
430 /* XXX */
431 void
432 ieee8023ad_portinit(struct agr_port *port)
433 {
434 	struct ieee8023ad_port *iport = IEEE8023AD_PORT(port);
435 
436 	memset(iport, 0, sizeof(iport));
437 
438 	lacp_portinit(port);
439 }
440 
441 void
442 ieee8023ad_portfini(struct agr_port *port)
443 {
444 	struct agr_softc *sc = AGR_SC_FROM_PORT(port);
445 
446 	AGR_LOCK(sc);
447 
448 	lacp_portfini(port);
449 
450 	AGR_UNLOCK(sc);
451 }
452 
453 void
454 ieee8023ad_ctor(struct agr_softc *sc)
455 {
456 	struct ieee8023ad_softc *isc = IEEE8023AD_SOFTC(sc);
457 	struct lacp_softc *lsc = &isc->isc_lacpsc;
458 
459 	lsc->lsc_active_aggregator = NULL;
460 	TAILQ_INIT(&lsc->lsc_aggregators);
461 	callout_init(&lsc->lsc_transit_callout, 0);
462 	callout_setfunc(&lsc->lsc_transit_callout, lacp_transit_expire, sc);
463 }
464 
465 void
466 ieee8023ad_dtor(struct agr_softc *sc)
467 {
468 	struct ieee8023ad_softc *isc = IEEE8023AD_SOFTC(sc);
469 	struct lacp_softc *lsc = &isc->isc_lacpsc;
470 
471 	LACP_DPRINTF((NULL, "%s\n", __func__));
472 
473 	callout_stop(&lsc->lsc_transit_callout);
474 	KASSERT(TAILQ_EMPTY(&lsc->lsc_aggregators));
475 	KASSERT(lsc->lsc_active_aggregator == NULL);
476 }
477 
478 /* -------------------- */
479 
480 struct agr_port *
481 ieee8023ad_select_tx_port(struct agr_softc *sc, struct mbuf *m)
482 {
483 	const struct lacp_softc *lsc = LACP_SOFTC(sc);
484 	const struct lacp_aggregator *la;
485 	const struct lacp_port *lp;
486 	uint32_t hash;
487 	int nports;
488 
489 	if (__predict_false(lsc->lsc_suppress_distributing &&
490 	    !AGR_ROUNDROBIN(sc))) {
491 		LACP_DPRINTF((NULL, "%s: waiting transit\n", __func__));
492 		sc->sc_if.if_collisions++; /* XXX abuse */
493 		return NULL;
494 	}
495 
496 	la = lsc->lsc_active_aggregator;
497 	if (__predict_false(la == NULL)) {
498 		LACP_DPRINTF((NULL, "%s: no active aggregator\n", __func__));
499 		return NULL;
500 	}
501 
502 	nports = la->la_nports;
503 	KASSERT(nports > 0);
504 
505 	if (AGR_ROUNDROBIN(sc)) {
506 		/* packet ordering rule violation */
507 		hash = sc->sc_rr_counter++;
508 	} else {
509 		hash = (*sc->sc_iftop->iftop_hashmbuf)(sc, m);
510 	}
511 	hash %= nports;
512 	lp = TAILQ_FIRST(&la->la_ports);
513 	KASSERT(lp != NULL);
514 	while (hash--) {
515 		lp = TAILQ_NEXT(lp, lp_dist_q);
516 		KASSERT(lp != NULL);
517 	}
518 
519 	KASSERT((lp->lp_state & LACP_STATE_DISTRIBUTING) != 0);
520 
521 	return lp->lp_agrport;
522 }
523 
524 /*
525  * lacp_suppress_distributing: drop transmit packets for a while
526  * to preserve packet ordering.
527  */
528 
529 static void
530 lacp_suppress_distributing(struct lacp_softc *lsc, struct lacp_aggregator *la)
531 {
532 
533 	if (lsc->lsc_active_aggregator != la) {
534 		return;
535 	}
536 
537 	LACP_DPRINTF((NULL, "%s\n", __func__));
538 	lsc->lsc_suppress_distributing = true;
539 	/* XXX should consider collector max delay */
540 	callout_schedule(&lsc->lsc_transit_callout,
541 	    LACP_TRANSIT_DELAY * hz / 1000);
542 }
543 
544 /* -------------------- */
545 
546 int
547 lacp_compare_peerinfo(const struct lacp_peerinfo *a,
548     const struct lacp_peerinfo *b)
549 {
550 
551 	return memcmp(a, b, offsetof(struct lacp_peerinfo, lip_state));
552 }
553 
554 int
555 lacp_compare_systemid(const struct lacp_systemid *a,
556     const struct lacp_systemid *b)
557 {
558 
559 	return memcmp(a, b, sizeof(*a));
560 }
561 
562 int
563 lacp_compare_portid(const struct lacp_portid *a,
564     const struct lacp_portid *b)
565 {
566 
567 	return memcmp(a, b, sizeof(*a));
568 }
569 
570 /* -------------------- */
571 
572 static uint64_t
573 lacp_aggregator_bandwidth(struct lacp_aggregator *la)
574 {
575 	struct lacp_port *lp;
576 	uint64_t speed;
577 
578 	lp = TAILQ_FIRST(&la->la_ports);
579 	if (lp == NULL) {
580 		return 0;
581 	}
582 
583 	speed = ifmedia_baudrate(lp->lp_media);
584 	speed *= la->la_nports;
585 	if (speed == 0) {
586 		LACP_DPRINTF((lp, "speed 0? media=0x%x nports=%d\n",
587 		    lp->lp_media, la->la_nports));
588 	}
589 
590 	return speed;
591 }
592 
593 /*
594  * lacp_select_active_aggregator: select an aggregator to be used to transmit
595  * packets from agr(4) interface.
596  */
597 
598 static void
599 lacp_select_active_aggregator(struct lacp_softc *lsc)
600 {
601 	struct lacp_aggregator *la;
602 	struct lacp_aggregator *best_la = NULL;
603 	uint64_t best_speed = 0;
604 #if defined(LACP_DEBUG)
605 	char buf[LACP_LAGIDSTR_MAX+1];
606 #endif /* defined(LACP_DEBUG) */
607 
608 	LACP_DPRINTF((NULL, "%s:\n", __func__));
609 
610 	TAILQ_FOREACH(la, &lsc->lsc_aggregators, la_q) {
611 		uint64_t speed;
612 
613 		if (la->la_nports == 0) {
614 			continue;
615 		}
616 
617 		speed = lacp_aggregator_bandwidth(la);
618 		LACP_DPRINTF((NULL, "%s, speed=%" PRIu64 ", nports=%d\n",
619 		    lacp_format_lagid_aggregator(la, buf, sizeof(buf)),
620 		    speed, la->la_nports));
621 		if (speed > best_speed ||
622 		    (speed == best_speed &&
623 		    la == lsc->lsc_active_aggregator)) {
624 			best_la = la;
625 			best_speed = speed;
626 		}
627 	}
628 
629 	KASSERT(best_la == NULL || best_la->la_nports > 0);
630 	KASSERT(best_la == NULL || !TAILQ_EMPTY(&best_la->la_ports));
631 
632 #if defined(LACP_DEBUG)
633 	if (lsc->lsc_active_aggregator != best_la) {
634 		LACP_DPRINTF((NULL, "active aggregator changed\n"));
635 		LACP_DPRINTF((NULL, "old %s\n",
636 		    lacp_format_lagid_aggregator(lsc->lsc_active_aggregator,
637 		    buf, sizeof(buf))));
638 	} else {
639 		LACP_DPRINTF((NULL, "active aggregator not changed\n"));
640 	}
641 	LACP_DPRINTF((NULL, "new %s\n",
642 	    lacp_format_lagid_aggregator(best_la, buf, sizeof(buf))));
643 #endif /* defined(LACP_DEBUG) */
644 
645 	if (lsc->lsc_active_aggregator != best_la) {
646 		lsc->lsc_active_aggregator = best_la;
647 		if (best_la) {
648 			lacp_suppress_distributing(lsc, best_la);
649 		}
650 	}
651 }
652 
653 uint16_t
654 lacp_compose_key(struct lacp_port *lp)
655 {
656 	u_int media = lp->lp_media;
657 	uint16_t key;
658 
659 	KASSERT(IFM_TYPE(media) == IFM_ETHER);
660 
661 	if (!(lp->lp_state & LACP_STATE_AGGREGATION)) {
662 
663 		/*
664 		 * non-aggregatable links should have unique keys.
665 		 *
666 		 * XXX this isn't really unique as if_index is 16 bit.
667 		 */
668 
669 		/* bit 0..14:	(some bits of) if_index of this port */
670 		key = lp->lp_agrport->port_ifp->if_index;
671 		/* bit 15:	1 */
672 		key |= 0x8000;
673 	} else {
674 		u_int subtype = IFM_SUBTYPE(media);
675 
676 		KASSERT((media & IFM_HDX) == 0); /* should be handled above */
677 		KASSERT((subtype & 0x1f) == subtype);
678 
679 		/* bit 0..4:	IFM_SUBTYPE */
680 		key = subtype;
681 		/* bit 5..14:	(some bits of) if_index of agr device */
682 		key |= 0x7fe0 & ((lp->lp_agrport->port_agrifp->if_index) << 5);
683 		/* bit 15:	0 */
684 	}
685 
686 	return htobe16(key);
687 }
688