xref: /freebsd/sys/netgraph/ng_bridge.c (revision e9e8876a4d6afc1ad5315faaa191b25121a813d7)
1 /*-
2  * Copyright (c) 2000 Whistle Communications, Inc.
3  * All rights reserved.
4  *
5  * Subject to the following obligations and disclaimer of warranty, use and
6  * redistribution of this software, in source or object code forms, with or
7  * without modifications are expressly permitted by Whistle Communications;
8  * provided, however, that:
9  * 1. Any and all reproductions of the source or object code must include the
10  *    copyright notice above and the following disclaimer of warranties; and
11  * 2. No rights are granted, in any manner or form, to use Whistle
12  *    Communications, Inc. trademarks, including the mark "WHISTLE
13  *    COMMUNICATIONS" on advertising, endorsements, or otherwise except as
14  *    such appears in the above copyright notice or in the software.
15  *
16  * THIS SOFTWARE IS BEING PROVIDED BY WHISTLE COMMUNICATIONS "AS IS", AND
17  * TO THE MAXIMUM EXTENT PERMITTED BY LAW, WHISTLE COMMUNICATIONS MAKES NO
18  * REPRESENTATIONS OR WARRANTIES, EXPRESS OR IMPLIED, REGARDING THIS SOFTWARE,
19  * INCLUDING WITHOUT LIMITATION, ANY AND ALL IMPLIED WARRANTIES OF
20  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, OR NON-INFRINGEMENT.
21  * WHISTLE COMMUNICATIONS DOES NOT WARRANT, GUARANTEE, OR MAKE ANY
22  * REPRESENTATIONS REGARDING THE USE OF, OR THE RESULTS OF THE USE OF THIS
23  * SOFTWARE IN TERMS OF ITS CORRECTNESS, ACCURACY, RELIABILITY OR OTHERWISE.
24  * IN NO EVENT SHALL WHISTLE COMMUNICATIONS BE LIABLE FOR ANY DAMAGES
25  * RESULTING FROM OR ARISING OUT OF ANY USE OF THIS SOFTWARE, INCLUDING
26  * WITHOUT LIMITATION, ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY,
27  * PUNITIVE, OR CONSEQUENTIAL DAMAGES, PROCUREMENT OF SUBSTITUTE GOODS OR
28  * SERVICES, LOSS OF USE, DATA OR PROFITS, HOWEVER CAUSED AND UNDER ANY
29  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
30  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
31  * THIS SOFTWARE, EVEN IF WHISTLE COMMUNICATIONS IS ADVISED OF THE POSSIBILITY
32  * OF SUCH DAMAGE.
33  *
34  * Author: Archie Cobbs <archie@freebsd.org>
35  *
36  * $FreeBSD$
37  */
38 
39 /*
40  * ng_bridge(4) netgraph node type
41  *
42  * The node performs standard intelligent Ethernet bridging over
43  * each of its connected hooks, or links.  A simple loop detection
44  * algorithm is included which disables a link for priv->conf.loopTimeout
45  * seconds when a host is seen to have jumped from one link to
46  * another within priv->conf.minStableAge seconds.
47  *
48  * We keep a hashtable that maps Ethernet addresses to host info,
49  * which is contained in struct ng_bridge_host's. These structures
50  * tell us on which link the host may be found. A host's entry will
51  * expire after priv->conf.maxStaleness seconds.
52  *
53  * This node is optimzed for stable networks, where machines jump
54  * from one port to the other only rarely.
55  */
56 
57 #include <sys/param.h>
58 #include <sys/systm.h>
59 #include <sys/kernel.h>
60 #include <sys/lock.h>
61 #include <sys/malloc.h>
62 #include <sys/mbuf.h>
63 #include <sys/errno.h>
64 #include <sys/rwlock.h>
65 #include <sys/syslog.h>
66 #include <sys/socket.h>
67 #include <sys/ctype.h>
68 #include <sys/types.h>
69 #include <sys/counter.h>
70 
71 #include <net/if.h>
72 #include <net/if_var.h>
73 #include <net/ethernet.h>
74 #include <net/vnet.h>
75 
76 #include <netinet/in.h>
77 #if 0	/* not used yet */
78 #include <netinet/ip_fw.h>
79 #endif
80 #include <netgraph/ng_message.h>
81 #include <netgraph/netgraph.h>
82 #include <netgraph/ng_parse.h>
83 #include <netgraph/ng_bridge.h>
84 
85 #ifdef NG_SEPARATE_MALLOC
86 static MALLOC_DEFINE(M_NETGRAPH_BRIDGE, "netgraph_bridge",
87     "netgraph bridge node");
88 #else
89 #define M_NETGRAPH_BRIDGE M_NETGRAPH
90 #endif
91 
92 /* Counter based stats */
93 struct ng_bridge_link_kernel_stats {
94 	counter_u64_t	recvOctets;	/* total octets rec'd on link */
95 	counter_u64_t	recvPackets;	/* total pkts rec'd on link */
96 	counter_u64_t	recvMulticasts;	/* multicast pkts rec'd on link */
97 	counter_u64_t	recvBroadcasts;	/* broadcast pkts rec'd on link */
98 	counter_u64_t	recvUnknown;	/* pkts rec'd with unknown dest addr */
99 	counter_u64_t	recvRunts;	/* pkts rec'd less than 14 bytes */
100 	counter_u64_t	recvInvalid;	/* pkts rec'd with bogus source addr */
101 	counter_u64_t	xmitOctets;	/* total octets xmit'd on link */
102 	counter_u64_t	xmitPackets;	/* total pkts xmit'd on link */
103 	counter_u64_t	xmitMulticasts;	/* multicast pkts xmit'd on link */
104 	counter_u64_t	xmitBroadcasts;	/* broadcast pkts xmit'd on link */
105 	counter_u64_t	loopDrops;	/* pkts dropped due to loopback */
106 	u_int64_t	loopDetects;	/* number of loop detections */
107 	counter_u64_t	memoryFailures;	/* times couldn't get mem or mbuf */
108 };
109 
110 /* Per-link private data */
111 struct ng_bridge_link {
112 	hook_p				hook;		/* netgraph hook */
113 	u_int16_t			loopCount;	/* loop ignore timer */
114 	unsigned int			learnMac : 1,   /* autolearn macs */
115 					sendUnknown : 1;/* send unknown macs out */
116 	struct ng_bridge_link_kernel_stats stats;	/* link stats */
117 };
118 typedef struct ng_bridge_link const *link_cp;	/* read only access */
119 
120 /* Per-node private data */
121 struct ng_bridge_private {
122 	struct ng_bridge_bucket	*tab;		/* hash table bucket array */
123 	struct ng_bridge_config	conf;		/* node configuration */
124 	node_p			node;		/* netgraph node */
125 	u_int			numHosts;	/* num entries in table */
126 	u_int			numBuckets;	/* num buckets in table */
127 	u_int			hashMask;	/* numBuckets - 1 */
128 	int			numLinks;	/* num connected links */
129 	unsigned int		persistent : 1,	/* can exist w/o hooks */
130 				sendUnknown : 1;/* links receive unknowns by default */
131 	struct callout		timer;		/* one second periodic timer */
132 };
133 typedef struct ng_bridge_private *priv_p;
134 typedef struct ng_bridge_private const *priv_cp;	/* read only access */
135 
136 /* Information about a host, stored in a hash table entry */
137 struct ng_bridge_host {
138 	u_char		addr[6];	/* ethernet address */
139 	link_p		link;		/* link where addr can be found */
140 	u_int16_t	age;		/* seconds ago entry was created */
141 	u_int16_t	staleness;	/* seconds ago host last heard from */
142 	SLIST_ENTRY(ng_bridge_host)	next;	/* next entry in bucket */
143 };
144 
145 /* Hash table bucket declaration */
146 SLIST_HEAD(ng_bridge_bucket, ng_bridge_host);
147 
148 /* Netgraph node methods */
149 static ng_constructor_t	ng_bridge_constructor;
150 static ng_rcvmsg_t	ng_bridge_rcvmsg;
151 static ng_shutdown_t	ng_bridge_shutdown;
152 static ng_newhook_t	ng_bridge_newhook;
153 static ng_rcvdata_t	ng_bridge_rcvdata;
154 static ng_disconnect_t	ng_bridge_disconnect;
155 
156 /* Other internal functions */
157 static void	ng_bridge_free_link(link_p link);
158 static struct	ng_bridge_host *ng_bridge_get(priv_cp priv, const u_char *addr);
159 static int	ng_bridge_put(priv_p priv, const u_char *addr, link_p link);
160 static void	ng_bridge_rehash(priv_p priv);
161 static void	ng_bridge_remove_hosts(priv_p priv, link_p link);
162 static void	ng_bridge_timeout(node_p node, hook_p hook, void *arg1, int arg2);
163 static const	char *ng_bridge_nodename(node_cp node);
164 
165 /* Ethernet broadcast */
166 static const u_char ng_bridge_bcast_addr[ETHER_ADDR_LEN] =
167     { 0xff, 0xff, 0xff, 0xff, 0xff, 0xff };
168 
169 /* Compare Ethernet addresses using 32 and 16 bit words instead of bytewise */
170 #define ETHER_EQUAL(a,b)	(((const u_int32_t *)(a))[0] \
171 					== ((const u_int32_t *)(b))[0] \
172 				    && ((const u_int16_t *)(a))[2] \
173 					== ((const u_int16_t *)(b))[2])
174 
175 /* Minimum and maximum number of hash buckets. Must be a power of two. */
176 #define MIN_BUCKETS		(1 << 5)	/* 32 */
177 #define MAX_BUCKETS		(1 << 14)	/* 16384 */
178 
179 /* Configuration default values */
180 #define DEFAULT_LOOP_TIMEOUT	60
181 #define DEFAULT_MAX_STALENESS	(15 * 60)	/* same as ARP timeout */
182 #define DEFAULT_MIN_STABLE_AGE	1
183 
184 /******************************************************************
185 		    NETGRAPH PARSE TYPES
186 ******************************************************************/
187 
188 /*
189  * How to determine the length of the table returned by NGM_BRIDGE_GET_TABLE
190  */
191 static int
192 ng_bridge_getTableLength(const struct ng_parse_type *type,
193 	const u_char *start, const u_char *buf)
194 {
195 	const struct ng_bridge_host_ary *const hary
196 	    = (const struct ng_bridge_host_ary *)(buf - sizeof(u_int32_t));
197 
198 	return hary->numHosts;
199 }
200 
201 /* Parse type for struct ng_bridge_host_ary */
202 static const struct ng_parse_struct_field ng_bridge_host_type_fields[]
203 	= NG_BRIDGE_HOST_TYPE_INFO(&ng_parse_enaddr_type);
204 static const struct ng_parse_type ng_bridge_host_type = {
205 	&ng_parse_struct_type,
206 	&ng_bridge_host_type_fields
207 };
208 static const struct ng_parse_array_info ng_bridge_hary_type_info = {
209 	&ng_bridge_host_type,
210 	ng_bridge_getTableLength
211 };
212 static const struct ng_parse_type ng_bridge_hary_type = {
213 	&ng_parse_array_type,
214 	&ng_bridge_hary_type_info
215 };
216 static const struct ng_parse_struct_field ng_bridge_host_ary_type_fields[]
217 	= NG_BRIDGE_HOST_ARY_TYPE_INFO(&ng_bridge_hary_type);
218 static const struct ng_parse_type ng_bridge_host_ary_type = {
219 	&ng_parse_struct_type,
220 	&ng_bridge_host_ary_type_fields
221 };
222 
223 /* Parse type for struct ng_bridge_config */
224 static const struct ng_parse_struct_field ng_bridge_config_type_fields[]
225 	= NG_BRIDGE_CONFIG_TYPE_INFO;
226 static const struct ng_parse_type ng_bridge_config_type = {
227 	&ng_parse_struct_type,
228 	&ng_bridge_config_type_fields
229 };
230 
231 /* Parse type for struct ng_bridge_link_stat */
232 static const struct ng_parse_struct_field ng_bridge_stats_type_fields[]
233 	= NG_BRIDGE_STATS_TYPE_INFO;
234 static const struct ng_parse_type ng_bridge_stats_type = {
235 	&ng_parse_struct_type,
236 	&ng_bridge_stats_type_fields
237 };
238 /* Parse type for struct ng_bridge_move_host */
239 static const struct ng_parse_struct_field ng_bridge_move_host_type_fields[]
240 	= NG_BRIDGE_MOVE_HOST_TYPE_INFO(&ng_parse_enaddr_type);
241 static const struct ng_parse_type ng_bridge_move_host_type = {
242 	&ng_parse_struct_type,
243 	&ng_bridge_move_host_type_fields
244 };
245 
246 /* List of commands and how to convert arguments to/from ASCII */
247 static const struct ng_cmdlist ng_bridge_cmdlist[] = {
248 	{
249 	  NGM_BRIDGE_COOKIE,
250 	  NGM_BRIDGE_SET_CONFIG,
251 	  "setconfig",
252 	  &ng_bridge_config_type,
253 	  NULL
254 	},
255 	{
256 	  NGM_BRIDGE_COOKIE,
257 	  NGM_BRIDGE_GET_CONFIG,
258 	  "getconfig",
259 	  NULL,
260 	  &ng_bridge_config_type
261 	},
262 	{
263 	  NGM_BRIDGE_COOKIE,
264 	  NGM_BRIDGE_RESET,
265 	  "reset",
266 	  NULL,
267 	  NULL
268 	},
269 	{
270 	  NGM_BRIDGE_COOKIE,
271 	  NGM_BRIDGE_GET_STATS,
272 	  "getstats",
273 	  &ng_parse_uint32_type,
274 	  &ng_bridge_stats_type
275 	},
276 	{
277 	  NGM_BRIDGE_COOKIE,
278 	  NGM_BRIDGE_CLR_STATS,
279 	  "clrstats",
280 	  &ng_parse_uint32_type,
281 	  NULL
282 	},
283 	{
284 	  NGM_BRIDGE_COOKIE,
285 	  NGM_BRIDGE_GETCLR_STATS,
286 	  "getclrstats",
287 	  &ng_parse_uint32_type,
288 	  &ng_bridge_stats_type
289 	},
290 	{
291 	  NGM_BRIDGE_COOKIE,
292 	  NGM_BRIDGE_GET_TABLE,
293 	  "gettable",
294 	  NULL,
295 	  &ng_bridge_host_ary_type
296 	},
297 	{
298 	  NGM_BRIDGE_COOKIE,
299 	  NGM_BRIDGE_SET_PERSISTENT,
300 	  "setpersistent",
301 	  NULL,
302 	  NULL
303 	},
304 	{
305 	  NGM_BRIDGE_COOKIE,
306 	  NGM_BRIDGE_MOVE_HOST,
307 	  "movehost",
308 	  &ng_bridge_move_host_type,
309 	  NULL
310 	},
311 	{ 0 }
312 };
313 
314 /* Node type descriptor */
315 static struct ng_type ng_bridge_typestruct = {
316 	.version =	NG_ABI_VERSION,
317 	.name =		NG_BRIDGE_NODE_TYPE,
318 	.constructor =	ng_bridge_constructor,
319 	.rcvmsg =	ng_bridge_rcvmsg,
320 	.shutdown =	ng_bridge_shutdown,
321 	.newhook =	ng_bridge_newhook,
322 	.rcvdata =	ng_bridge_rcvdata,
323 	.disconnect =	ng_bridge_disconnect,
324 	.cmdlist =	ng_bridge_cmdlist,
325 };
326 NETGRAPH_INIT(bridge, &ng_bridge_typestruct);
327 
328 /******************************************************************
329 		    NETGRAPH NODE METHODS
330 ******************************************************************/
331 
332 /*
333  * Node constructor
334  */
335 static int
336 ng_bridge_constructor(node_p node)
337 {
338 	priv_p priv;
339 
340 	/* Allocate and initialize private info */
341 	priv = malloc(sizeof(*priv), M_NETGRAPH_BRIDGE, M_WAITOK | M_ZERO);
342 	ng_callout_init(&priv->timer);
343 
344 	/* Allocate and initialize hash table, etc. */
345 	priv->tab = malloc(MIN_BUCKETS * sizeof(*priv->tab),
346 	    M_NETGRAPH_BRIDGE, M_WAITOK | M_ZERO);
347 	priv->numBuckets = MIN_BUCKETS;
348 	priv->hashMask = MIN_BUCKETS - 1;
349 	priv->conf.debugLevel = 1;
350 	priv->conf.loopTimeout = DEFAULT_LOOP_TIMEOUT;
351 	priv->conf.maxStaleness = DEFAULT_MAX_STALENESS;
352 	priv->conf.minStableAge = DEFAULT_MIN_STABLE_AGE;
353 	priv->sendUnknown = 1;	       /* classic bridge */
354 
355 	NG_NODE_SET_PRIVATE(node, priv);
356 	priv->node = node;
357 
358 	/* Start timer; timer is always running while node is alive */
359 	ng_callout(&priv->timer, node, NULL, hz, ng_bridge_timeout, NULL, 0);
360 
361 	/* Done */
362 	return (0);
363 }
364 
365 /*
366  * Method for attaching a new hook
367  */
368 static	int
369 ng_bridge_newhook(node_p node, hook_p hook, const char *name)
370 {
371 	const priv_p priv = NG_NODE_PRIVATE(node);
372 	char linkName[NG_HOOKSIZ];
373 	u_int32_t linkNum;
374 	link_p link;
375 	const char *prefix = NG_BRIDGE_HOOK_LINK_PREFIX;
376 	bool isUplink;
377 
378 	/* Check for a link hook */
379 	if (strlen(name) <= strlen(prefix))
380 		return (EINVAL);       /* Unknown hook name */
381 
382 	isUplink = (name[0] == 'u');
383 	if (isUplink)
384 		prefix = NG_BRIDGE_HOOK_UPLINK_PREFIX;
385 
386 	/* primitive parsing */
387 	linkNum = strtoul(name + strlen(prefix), NULL, 10);
388 	/* validation by comparing against the reconstucted name  */
389 	snprintf(linkName, sizeof(linkName), "%s%u", prefix, linkNum);
390 	if (strcmp(linkName, name) != 0)
391 		return (EINVAL);
392 
393 	if (linkNum == 0 && isUplink)
394 		return (EINVAL);
395 
396 	if(NG_PEER_NODE(hook) == node)
397 	        return (ELOOP);
398 
399 	link = malloc(sizeof(*link), M_NETGRAPH_BRIDGE, M_NOWAIT | M_ZERO);
400 	if (link == NULL)
401 		return (ENOMEM);
402 
403 #define	NG_BRIDGE_COUNTER_ALLOC(f) do {			\
404 	link->stats.f = counter_u64_alloc(M_NOWAIT);	\
405 	if (link->stats.f == NULL)			\
406 		goto nomem;				\
407 } while (0)
408 	NG_BRIDGE_COUNTER_ALLOC(recvOctets);
409 	NG_BRIDGE_COUNTER_ALLOC(recvPackets);
410 	NG_BRIDGE_COUNTER_ALLOC(recvMulticasts);
411 	NG_BRIDGE_COUNTER_ALLOC(recvBroadcasts);
412 	NG_BRIDGE_COUNTER_ALLOC(recvUnknown);
413 	NG_BRIDGE_COUNTER_ALLOC(recvRunts);
414 	NG_BRIDGE_COUNTER_ALLOC(recvInvalid);
415 	NG_BRIDGE_COUNTER_ALLOC(xmitOctets);
416 	NG_BRIDGE_COUNTER_ALLOC(xmitPackets);
417 	NG_BRIDGE_COUNTER_ALLOC(xmitMulticasts);
418 	NG_BRIDGE_COUNTER_ALLOC(xmitBroadcasts);
419 	NG_BRIDGE_COUNTER_ALLOC(loopDrops);
420 	NG_BRIDGE_COUNTER_ALLOC(memoryFailures);
421 #undef NG_BRIDGE_COUNTER_ALLOC
422 
423 	link->hook = hook;
424 	if (isUplink) {
425 		link->learnMac = 0;
426 		link->sendUnknown = 1;
427 		if (priv->numLinks == 0)	/* if the first link is an uplink */
428 			priv->sendUnknown = 0;	/* switch to restrictive mode */
429 	} else {
430 		link->learnMac = 1;
431 		link->sendUnknown = priv->sendUnknown;
432 	}
433 
434 	NG_HOOK_SET_PRIVATE(hook, link);
435 	priv->numLinks++;
436 	return (0);
437 
438 nomem:
439 	ng_bridge_free_link(link);
440 	return (ENOMEM);
441 }
442 
443 /*
444  * Receive a control message
445  */
446 static void
447 ng_bridge_clear_link_stats(struct ng_bridge_link_kernel_stats *p)
448 {
449 	counter_u64_zero(p->recvOctets);
450 	counter_u64_zero(p->recvPackets);
451 	counter_u64_zero(p->recvMulticasts);
452 	counter_u64_zero(p->recvBroadcasts);
453 	counter_u64_zero(p->recvUnknown);
454 	counter_u64_zero(p->recvRunts);
455 	counter_u64_zero(p->recvInvalid);
456 	counter_u64_zero(p->xmitOctets);
457 	counter_u64_zero(p->xmitPackets);
458 	counter_u64_zero(p->xmitMulticasts);
459 	counter_u64_zero(p->xmitBroadcasts);
460 	counter_u64_zero(p->loopDrops);
461 	p->loopDetects = 0;
462 	counter_u64_zero(p->memoryFailures);
463 }
464 
465 static void
466 ng_bridge_free_link(link_p link)
467 {
468 	counter_u64_free(link->stats.recvOctets);
469 	counter_u64_free(link->stats.recvPackets);
470 	counter_u64_free(link->stats.recvMulticasts);
471 	counter_u64_free(link->stats.recvBroadcasts);
472 	counter_u64_free(link->stats.recvUnknown);
473 	counter_u64_free(link->stats.recvRunts);
474 	counter_u64_free(link->stats.recvInvalid);
475 	counter_u64_free(link->stats.xmitOctets);
476 	counter_u64_free(link->stats.xmitPackets);
477 	counter_u64_free(link->stats.xmitMulticasts);
478 	counter_u64_free(link->stats.xmitBroadcasts);
479 	counter_u64_free(link->stats.loopDrops);
480 	counter_u64_free(link->stats.memoryFailures);
481 	free(link, M_NETGRAPH_BRIDGE);
482 }
483 
484 static int
485 ng_bridge_reset_link(hook_p hook, void *arg __unused)
486 {
487 	link_p priv = NG_HOOK_PRIVATE(hook);
488 
489 	priv->loopCount = 0;
490 	ng_bridge_clear_link_stats(&priv->stats);
491 	return (1);
492 }
493 
494 static int
495 ng_bridge_rcvmsg(node_p node, item_p item, hook_p lasthook)
496 {
497 	const priv_p priv = NG_NODE_PRIVATE(node);
498 	struct ng_mesg *resp = NULL;
499 	int error = 0;
500 	struct ng_mesg *msg;
501 
502 	NGI_GET_MSG(item, msg);
503 	switch (msg->header.typecookie) {
504 	case NGM_BRIDGE_COOKIE:
505 		switch (msg->header.cmd) {
506 		case NGM_BRIDGE_GET_CONFIG:
507 		    {
508 			struct ng_bridge_config *conf;
509 
510 			NG_MKRESPONSE(resp, msg,
511 			    sizeof(struct ng_bridge_config), M_NOWAIT);
512 			if (resp == NULL) {
513 				error = ENOMEM;
514 				break;
515 			}
516 			conf = (struct ng_bridge_config *)resp->data;
517 			*conf = priv->conf;	/* no sanity checking needed */
518 			break;
519 		    }
520 		case NGM_BRIDGE_SET_CONFIG:
521 		    {
522 			struct ng_bridge_config *conf;
523 
524 			if (msg->header.arglen
525 			    != sizeof(struct ng_bridge_config)) {
526 				error = EINVAL;
527 				break;
528 			}
529 			conf = (struct ng_bridge_config *)msg->data;
530 			priv->conf = *conf;
531 			break;
532 		    }
533 		case NGM_BRIDGE_RESET:
534 		    {
535 			hook_p rethook;
536 
537 			/* Flush all entries in the hash table */
538 			ng_bridge_remove_hosts(priv, NULL);
539 
540 			/* Reset all loop detection counters and stats */
541 			NG_NODE_FOREACH_HOOK(node, ng_bridge_reset_link, NULL,
542 			    rethook);
543 			break;
544 		    }
545 		case NGM_BRIDGE_GET_STATS:
546 		case NGM_BRIDGE_CLR_STATS:
547 		case NGM_BRIDGE_GETCLR_STATS:
548 		    {
549 			hook_p hook;
550 			link_p link;
551 			char linkName[NG_HOOKSIZ];
552 			int linkNum;
553 
554 			/* Get link number */
555 			if (msg->header.arglen != sizeof(u_int32_t)) {
556 				error = EINVAL;
557 				break;
558 			}
559 			linkNum = *((int32_t *)msg->data);
560 			if (linkNum < 0)
561 				snprintf(linkName, sizeof(linkName),
562 				    "%s%u", NG_BRIDGE_HOOK_UPLINK_PREFIX, -linkNum);
563 			else
564 				snprintf(linkName, sizeof(linkName),
565 				    "%s%u", NG_BRIDGE_HOOK_LINK_PREFIX, linkNum);
566 
567 			if ((hook = ng_findhook(node, linkName)) == NULL) {
568 				error = ENOTCONN;
569 				break;
570 			}
571 			link = NG_HOOK_PRIVATE(hook);
572 
573 			/* Get/clear stats */
574 			if (msg->header.cmd != NGM_BRIDGE_CLR_STATS) {
575 				struct ng_bridge_link_stats *rs;
576 
577 				NG_MKRESPONSE(resp, msg,
578 				    sizeof(link->stats), M_NOWAIT);
579 				if (resp == NULL) {
580 					error = ENOMEM;
581 					break;
582 				}
583 				rs = (struct ng_bridge_link_stats *)resp->data;
584 #define FETCH(x)	rs->x = counter_u64_fetch(link->stats.x)
585 				FETCH(recvOctets);
586 				FETCH(recvPackets);
587 				FETCH(recvMulticasts);
588 				FETCH(recvBroadcasts);
589 				FETCH(recvUnknown);
590 				FETCH(recvRunts);
591 				FETCH(recvInvalid);
592 				FETCH(xmitOctets);
593 				FETCH(xmitPackets);
594 				FETCH(xmitMulticasts);
595 				FETCH(xmitBroadcasts);
596 				FETCH(loopDrops);
597 				rs->loopDetects = link->stats.loopDetects;
598 				FETCH(memoryFailures);
599 #undef FETCH
600 			}
601 			if (msg->header.cmd != NGM_BRIDGE_GET_STATS)
602 				ng_bridge_clear_link_stats(&link->stats);
603 			break;
604 		    }
605 		case NGM_BRIDGE_GET_TABLE:
606 		    {
607 			struct ng_bridge_host_ary *ary;
608 			struct ng_bridge_host *host;
609 			int i = 0, bucket;
610 
611 			NG_MKRESPONSE(resp, msg, sizeof(*ary)
612 			    + (priv->numHosts * sizeof(*ary->hosts)), M_NOWAIT);
613 			if (resp == NULL) {
614 				error = ENOMEM;
615 				break;
616 			}
617 			ary = (struct ng_bridge_host_ary *)resp->data;
618 			ary->numHosts = priv->numHosts;
619 			for (bucket = 0; bucket < priv->numBuckets; bucket++) {
620 				SLIST_FOREACH(host, &priv->tab[bucket], next) {
621 					memcpy(ary->hosts[i].addr,
622 					       host->addr,
623 					       sizeof(ary->hosts[i].addr));
624 					ary->hosts[i].age       = host->age;
625 					ary->hosts[i].staleness = host->staleness;
626 					strncpy(ary->hosts[i].hook,
627 						NG_HOOK_NAME(host->link->hook),
628 						sizeof(ary->hosts[i].hook));
629 					i++;
630 				}
631 			}
632 			break;
633 		    }
634 		case NGM_BRIDGE_SET_PERSISTENT:
635 		    {
636 			priv->persistent = 1;
637 			break;
638 		    }
639 		case NGM_BRIDGE_MOVE_HOST:
640 		{
641 			struct ng_bridge_move_host *mh;
642 			hook_p hook;
643 
644 			if (msg->header.arglen < sizeof(*mh)) {
645 				error = EINVAL;
646 				break;
647 			}
648 			mh = (struct ng_bridge_move_host *)msg->data;
649 			hook = (mh->hook[0] == 0)
650 			    ? lasthook
651 			    : ng_findhook(node, mh->hook);
652 			if (hook == NULL) {
653 				error = ENOENT;
654 				break;
655 			}
656 			error = ng_bridge_put(priv, mh->addr, NG_HOOK_PRIVATE(hook));
657 			break;
658 		}
659 		default:
660 			error = EINVAL;
661 			break;
662 		}
663 		break;
664 	default:
665 		error = EINVAL;
666 		break;
667 	}
668 
669 	/* Done */
670 	NG_RESPOND_MSG(error, node, item, resp);
671 	NG_FREE_MSG(msg);
672 	return (error);
673 }
674 
675 /*
676  * Receive data on a hook
677  */
678 struct ng_bridge_send_ctx {
679 	link_p foundFirst, incoming;
680 	struct mbuf * m;
681 	int manycast, error;
682 };
683 
684 /*
685  * Update stats and send out
686  */
687 static inline int
688 ng_bridge_send_data(link_cp dst, int manycast, struct mbuf *m, item_p item) {
689 	int error = 0;
690 	size_t len = m->m_pkthdr.len;
691 
692 	if(item != NULL)
693 		NG_FWD_NEW_DATA(error, item, dst->hook, m);
694 	else
695 		NG_SEND_DATA_ONLY(error, dst->hook, m);
696 
697 	if (error) {
698 		if (error == ENOMEM)
699 			counter_u64_add(dst->stats.memoryFailures, 1);
700 		/* The packet is still ours */
701 		if (item != NULL)
702 			NG_FREE_ITEM(item);
703 		if (m != NULL)
704 			NG_FREE_M(m);
705 		return (error);
706 	}
707 
708 	counter_u64_add(dst->stats.xmitPackets, 1);
709 	counter_u64_add(dst->stats.xmitOctets, len);
710 	switch (manycast) {
711 	default:		       /* unknown unicast */
712 		break;
713 	case 1:			       /* multicast */
714 		counter_u64_add(dst->stats.xmitMulticasts, 1);
715 		break;
716 	case 2:			       /* broadcast */
717 		counter_u64_add(dst->stats.xmitBroadcasts, 1);
718 		break;
719 	}
720 	return (0);
721 }
722 
723 /*
724  * Loop body for sending to multiple destinations
725  * return 0 to stop looping
726  */
727 static int
728 ng_bridge_send_ctx(hook_p dst, void *arg)
729 {
730 	struct ng_bridge_send_ctx *ctx = arg;
731 	link_p destLink = NG_HOOK_PRIVATE(dst);
732 	struct mbuf *m2 = NULL;
733 	int error = 0;
734 
735 	/* Skip incoming link */
736 	if (destLink == ctx->incoming) {
737 		return (1);
738 	}
739 
740 	/* Skip sending unknowns to undesired links  */
741 	if (!ctx->manycast && !destLink->sendUnknown)
742 		return (1);
743 
744 	if (ctx->foundFirst == NULL) {
745 		/*
746 		 * This is the first usable link we have found.
747 		 * Reserve it for the originals.
748 		 * If we never find another we save a copy.
749 		 */
750 		ctx->foundFirst = destLink;
751 		return (1);
752 	}
753 
754 	/*
755 	 * It's usable link but not the reserved (first) one.
756 	 * Copy mbuf info for sending.
757 	 */
758 	m2 = m_dup(ctx->m, M_NOWAIT);
759 	if (m2 == NULL) {
760 		counter_u64_add(ctx->incoming->stats.memoryFailures, 1);
761 		ctx->error = ENOBUFS;
762 		return (0);	       /* abort loop, do not try again and again */
763 	}
764 
765 	/* Send packet */
766 	error = ng_bridge_send_data(destLink, ctx->manycast, m2, NULL);
767 	if (error)
768 	  ctx->error = error;
769 	return (1);
770 }
771 
772 static int
773 ng_bridge_rcvdata(hook_p hook, item_p item)
774 {
775 	const node_p node = NG_HOOK_NODE(hook);
776 	const priv_p priv = NG_NODE_PRIVATE(node);
777 	struct ng_bridge_host *host;
778 	struct ether_header *eh;
779 	struct ng_bridge_send_ctx ctx = { 0 };
780 	hook_p ret;
781 
782 	NGI_GET_M(item, ctx.m);
783 
784 	ctx.incoming = NG_HOOK_PRIVATE(hook);
785 	/* Sanity check packet and pull up header */
786 	if (ctx.m->m_pkthdr.len < ETHER_HDR_LEN) {
787 		counter_u64_add(ctx.incoming->stats.recvRunts, 1);
788 		NG_FREE_ITEM(item);
789 		NG_FREE_M(ctx.m);
790 		return (EINVAL);
791 	}
792 	if (ctx.m->m_len < ETHER_HDR_LEN && !(ctx.m = m_pullup(ctx.m, ETHER_HDR_LEN))) {
793 		counter_u64_add(ctx.incoming->stats.memoryFailures, 1);
794 		NG_FREE_ITEM(item);
795 		return (ENOBUFS);
796 	}
797 	eh = mtod(ctx.m, struct ether_header *);
798 	if ((eh->ether_shost[0] & 1) != 0) {
799 		counter_u64_add(ctx.incoming->stats.recvInvalid, 1);
800 		NG_FREE_ITEM(item);
801 		NG_FREE_M(ctx.m);
802 		return (EINVAL);
803 	}
804 
805 	/* Is link disabled due to a loopback condition? */
806 	if (ctx.incoming->loopCount != 0) {
807 		counter_u64_add(ctx.incoming->stats.loopDrops, 1);
808 		NG_FREE_ITEM(item);
809 		NG_FREE_M(ctx.m);
810 		return (ELOOP);
811 	}
812 
813 	/* Update stats */
814 	counter_u64_add(ctx.incoming->stats.recvPackets, 1);
815 	counter_u64_add(ctx.incoming->stats.recvOctets, ctx.m->m_pkthdr.len);
816 	if ((ctx.manycast = (eh->ether_dhost[0] & 1)) != 0) {
817 		if (ETHER_EQUAL(eh->ether_dhost, ng_bridge_bcast_addr)) {
818 			counter_u64_add(ctx.incoming->stats.recvBroadcasts, 1);
819 			ctx.manycast = 2;
820 		} else
821 			counter_u64_add(ctx.incoming->stats.recvMulticasts, 1);
822 	}
823 
824 	/* Look up packet's source Ethernet address in hashtable */
825 	if ((host = ng_bridge_get(priv, eh->ether_shost)) != NULL)
826 		/* Update time since last heard from this host.
827 		 * This is safe without locking, because it's
828 		 * the only operation during shared access.
829 		 */
830 		if (__predict_false(host->staleness > 0))
831 			host->staleness = 0;
832 
833 	if ((host == NULL && ctx.incoming->learnMac) ||
834 	    (host != NULL && host->link != ctx.incoming)) {
835 		struct ng_mesg *msg;
836 		struct ng_bridge_move_host *mh;
837 		int error = 0;
838 
839 		NG_MKMESSAGE(msg, NGM_BRIDGE_COOKIE, NGM_BRIDGE_MOVE_HOST,
840 		    sizeof(*mh), M_NOWAIT);
841 		if (msg == NULL) {
842 			counter_u64_add(ctx.incoming->stats.memoryFailures, 1);
843 			NG_FREE_ITEM(item);
844 			NG_FREE_M(ctx.m);
845 			return (ENOMEM);
846 		}
847 		mh = (struct ng_bridge_move_host *)msg->data;
848 		strncpy(mh->hook, NG_HOOK_NAME(ctx.incoming->hook),
849 		    sizeof(mh->hook));
850 		memcpy(mh->addr, eh->ether_shost, sizeof(mh->addr));
851 		NG_SEND_MSG_ID(error, node, msg, NG_NODE_ID(node),
852 		    NG_NODE_ID(node));
853 		if (error)
854 			counter_u64_add(ctx.incoming->stats.memoryFailures, 1);
855 	}
856 
857 	if (host != NULL && host->link != ctx.incoming) {
858 		if (host->age < priv->conf.minStableAge) {
859 			/* Drop packet on instable links */
860 			counter_u64_add(ctx.incoming->stats.loopDrops, 1);
861 			NG_FREE_ITEM(item);
862 			NG_FREE_M(ctx.m);
863 			return (ELOOP);
864 		}
865 	}
866 
867 	/* Run packet through ipfw processing, if enabled */
868 #if 0
869 	if (priv->conf.ipfw[linkNum] && V_fw_enable && V_ip_fw_chk_ptr != NULL) {
870 		/* XXX not implemented yet */
871 	}
872 #endif
873 
874 	/*
875 	 * If unicast and destination host known, deliver to host's link,
876 	 * unless it is the same link as the packet came in on.
877 	 */
878 	if (!ctx.manycast) {
879 		/* Determine packet destination link */
880 		if ((host = ng_bridge_get(priv, eh->ether_dhost)) != NULL) {
881 			link_p destLink = host->link;
882 
883 			/* If destination same as incoming link, do nothing */
884 			if (destLink == ctx.incoming) {
885 				NG_FREE_ITEM(item);
886 				NG_FREE_M(ctx.m);
887 				return (0);
888 			}
889 
890 			/* Deliver packet out the destination link */
891 			return (ng_bridge_send_data(destLink, ctx.manycast, ctx.m, item));
892 		}
893 
894 		/* Destination host is not known */
895 		counter_u64_add(ctx.incoming->stats.recvUnknown, 1);
896 	}
897 
898 	/* Distribute unknown, multicast, broadcast pkts to all other links */
899 	NG_NODE_FOREACH_HOOK(node, ng_bridge_send_ctx, &ctx, ret);
900 
901 	/* Finally send out on the first link found */
902 	if (ctx.foundFirst != NULL) {
903 		int error = ng_bridge_send_data(ctx.foundFirst, ctx.manycast, ctx.m, item);
904 		if (error)
905 			ctx.error = error;
906 	} else {		       /* nothing to send at all */
907 		NG_FREE_ITEM(item);
908 		NG_FREE_M(ctx.m);
909 	}
910 
911 	return (ctx.error);
912 }
913 
914 /*
915  * Shutdown node
916  */
917 static int
918 ng_bridge_shutdown(node_p node)
919 {
920 	const priv_p priv = NG_NODE_PRIVATE(node);
921 
922 	/*
923 	 * Shut down everything including the timer.  Even if the
924 	 * callout has already been dequeued and is about to be
925 	 * run, ng_bridge_timeout() won't be fired as the node
926 	 * is already marked NGF_INVALID, so we're safe to free
927 	 * the node now.
928 	 */
929 	KASSERT(priv->numLinks == 0 && priv->numHosts == 0,
930 	    ("%s: numLinks=%d numHosts=%d",
931 	    __func__, priv->numLinks, priv->numHosts));
932 	ng_uncallout(&priv->timer, node);
933 	NG_NODE_SET_PRIVATE(node, NULL);
934 	NG_NODE_UNREF(node);
935 	free(priv->tab, M_NETGRAPH_BRIDGE);
936 	free(priv, M_NETGRAPH_BRIDGE);
937 	return (0);
938 }
939 
940 /*
941  * Hook disconnection.
942  */
943 static int
944 ng_bridge_disconnect(hook_p hook)
945 {
946 	const priv_p priv = NG_NODE_PRIVATE(NG_HOOK_NODE(hook));
947 	link_p link = NG_HOOK_PRIVATE(hook);
948 
949 	/* Remove all hosts associated with this link */
950 	ng_bridge_remove_hosts(priv, link);
951 
952 	/* Free associated link information */
953 	ng_bridge_free_link(link);
954 	priv->numLinks--;
955 
956 	/* If no more hooks, go away */
957 	if ((NG_NODE_NUMHOOKS(NG_HOOK_NODE(hook)) == 0)
958 	    && (NG_NODE_IS_VALID(NG_HOOK_NODE(hook)))
959 	    && !priv->persistent) {
960 		ng_rmnode_self(NG_HOOK_NODE(hook));
961 	}
962 	return (0);
963 }
964 
965 /******************************************************************
966 		    HASH TABLE FUNCTIONS
967 ******************************************************************/
968 
969 /*
970  * Hash algorithm
971  */
972 #define HASH(addr,mask)		( (((const u_int16_t *)(addr))[0] 	\
973 				 ^ ((const u_int16_t *)(addr))[1] 	\
974 				 ^ ((const u_int16_t *)(addr))[2]) & (mask) )
975 
976 /*
977  * Find a host entry in the table.
978  */
979 static struct ng_bridge_host *
980 ng_bridge_get(priv_cp priv, const u_char *addr)
981 {
982 	const int bucket = HASH(addr, priv->hashMask);
983 	struct ng_bridge_host *host;
984 
985 	SLIST_FOREACH(host, &priv->tab[bucket], next) {
986 		if (ETHER_EQUAL(host->addr, addr))
987 			return (host);
988 	}
989 	return (NULL);
990 }
991 
992 /*
993  * Add a host entry to the table. If it already exists, move it
994  * to the new link. Returns 0 on success.
995  */
996 static int
997 ng_bridge_put(priv_p priv, const u_char *addr, link_p link)
998 {
999 	const int bucket = HASH(addr, priv->hashMask);
1000 	struct ng_bridge_host *host;
1001 
1002 	if ((host = ng_bridge_get(priv, addr)) != NULL) {
1003 		/* Host already on the correct link? */
1004 		if (host->link == link)
1005 			return 0;
1006 
1007 		/* Move old host over to new link */
1008 		if (host->age >= priv->conf.minStableAge) {
1009 			host->link = link;
1010 			host->age = 0;
1011 			return (0);
1012 		}
1013 		/*
1014 		 * If the host was recently moved to the old link and
1015 		 * it's now jumping to a new link, declare a loopback
1016 		 * condition.
1017 		 */
1018 		if (priv->conf.debugLevel >= 2)
1019 		    log(LOG_WARNING, "ng_bridge: %s:"
1020 			" loopback detected on %s\n",
1021 			ng_bridge_nodename(priv->node),
1022 			NG_HOOK_NAME(link->hook));
1023 
1024 		/* Mark link as linka non grata */
1025 		link->loopCount = priv->conf.loopTimeout;
1026 		link->stats.loopDetects++;
1027 
1028 		/* Forget all hosts on this link */
1029 		ng_bridge_remove_hosts(priv, link);
1030 		return (ELOOP);
1031 	}
1032 
1033 	/* Allocate and initialize new hashtable entry */
1034 	host = malloc(sizeof(*host), M_NETGRAPH_BRIDGE, M_NOWAIT);
1035 	if (host == NULL)
1036 		return (ENOMEM);
1037 	bcopy(addr, host->addr, ETHER_ADDR_LEN);
1038 	host->link = link;
1039 	host->staleness = 0;
1040 	host->age = 0;
1041 
1042 	/* Add new element to hash bucket */
1043 	SLIST_INSERT_HEAD(&priv->tab[bucket], host, next);
1044 	priv->numHosts++;
1045 
1046 	/* Resize table if necessary */
1047 	ng_bridge_rehash(priv);
1048 	return (0);
1049 }
1050 
1051 /*
1052  * Resize the hash table. We try to maintain the number of buckets
1053  * such that the load factor is in the range 0.25 to 1.0.
1054  *
1055  * If we can't get the new memory then we silently fail. This is OK
1056  * because things will still work and we'll try again soon anyway.
1057  */
1058 static void
1059 ng_bridge_rehash(priv_p priv)
1060 {
1061 	struct ng_bridge_bucket *newTab;
1062 	int oldBucket, newBucket;
1063 	int newNumBuckets;
1064 	u_int newMask;
1065 
1066 	/* Is table too full or too empty? */
1067 	if (priv->numHosts > priv->numBuckets
1068 	    && (priv->numBuckets << 1) <= MAX_BUCKETS)
1069 		newNumBuckets = priv->numBuckets << 1;
1070 	else if (priv->numHosts < (priv->numBuckets >> 2)
1071 	    && (priv->numBuckets >> 2) >= MIN_BUCKETS)
1072 		newNumBuckets = priv->numBuckets >> 2;
1073 	else
1074 		return;
1075 	newMask = newNumBuckets - 1;
1076 
1077 	/* Allocate and initialize new table */
1078 	newTab = malloc(newNumBuckets * sizeof(*newTab),
1079 	    M_NETGRAPH_BRIDGE, M_NOWAIT | M_ZERO);
1080 	if (newTab == NULL)
1081 		return;
1082 
1083 	/* Move all entries from old table to new table */
1084 	for (oldBucket = 0; oldBucket < priv->numBuckets; oldBucket++) {
1085 		struct ng_bridge_bucket *const oldList = &priv->tab[oldBucket];
1086 
1087 		while (!SLIST_EMPTY(oldList)) {
1088 			struct ng_bridge_host *const host
1089 			    = SLIST_FIRST(oldList);
1090 
1091 			SLIST_REMOVE_HEAD(oldList, next);
1092 			newBucket = HASH(host->addr, newMask);
1093 			SLIST_INSERT_HEAD(&newTab[newBucket], host, next);
1094 		}
1095 	}
1096 
1097 	/* Replace old table with new one */
1098 	if (priv->conf.debugLevel >= 3) {
1099 		log(LOG_INFO, "ng_bridge: %s: table size %d -> %d\n",
1100 		    ng_bridge_nodename(priv->node),
1101 		    priv->numBuckets, newNumBuckets);
1102 	}
1103 	free(priv->tab, M_NETGRAPH_BRIDGE);
1104 	priv->numBuckets = newNumBuckets;
1105 	priv->hashMask = newMask;
1106 	priv->tab = newTab;
1107 	return;
1108 }
1109 
1110 /******************************************************************
1111 		    MISC FUNCTIONS
1112 ******************************************************************/
1113 
1114 /*
1115  * Remove all hosts associated with a specific link from the hashtable.
1116  * If linkNum == -1, then remove all hosts in the table.
1117  */
1118 static void
1119 ng_bridge_remove_hosts(priv_p priv, link_p link)
1120 {
1121 	int bucket;
1122 
1123 	for (bucket = 0; bucket < priv->numBuckets; bucket++) {
1124 		struct ng_bridge_host **hptr = &SLIST_FIRST(&priv->tab[bucket]);
1125 
1126 		while (*hptr != NULL) {
1127 			struct ng_bridge_host *const host = *hptr;
1128 
1129 			if (link == NULL || host->link == link) {
1130 				*hptr = SLIST_NEXT(host, next);
1131 				free(host, M_NETGRAPH_BRIDGE);
1132 				priv->numHosts--;
1133 			} else
1134 				hptr = &SLIST_NEXT(host, next);
1135 		}
1136 	}
1137 }
1138 
1139 /*
1140  * Handle our once-per-second timeout event. We do two things:
1141  * we decrement link->loopCount for those links being muted due to
1142  * a detected loopback condition, and we remove any hosts from
1143  * the hashtable whom we haven't heard from in a long while.
1144  */
1145 static int
1146 ng_bridge_unmute(hook_p hook, void *arg)
1147 {
1148 	link_p link = NG_HOOK_PRIVATE(hook);
1149 	node_p node = NG_HOOK_NODE(hook);
1150 	priv_p priv = NG_NODE_PRIVATE(node);
1151 	int *counter = arg;
1152 
1153 	if (link->loopCount != 0) {
1154 		link->loopCount--;
1155 		if (link->loopCount == 0 && priv->conf.debugLevel >= 2) {
1156 			log(LOG_INFO, "ng_bridge: %s:"
1157 			    " restoring looped back %s\n",
1158 			    ng_bridge_nodename(node), NG_HOOK_NAME(hook));
1159 		}
1160 	}
1161 	(*counter)++;
1162 	return (1);
1163 }
1164 
1165 static void
1166 ng_bridge_timeout(node_p node, hook_p hook, void *arg1, int arg2)
1167 {
1168 	const priv_p priv = NG_NODE_PRIVATE(node);
1169 	int bucket;
1170 	int counter = 0;
1171 	hook_p ret;
1172 
1173 	/* Update host time counters and remove stale entries */
1174 	for (bucket = 0; bucket < priv->numBuckets; bucket++) {
1175 		struct ng_bridge_host **hptr = &SLIST_FIRST(&priv->tab[bucket]);
1176 
1177 		while (*hptr != NULL) {
1178 			struct ng_bridge_host *const host = *hptr;
1179 
1180 			/* Remove hosts we haven't heard from in a while */
1181 			if (++host->staleness >= priv->conf.maxStaleness) {
1182 				*hptr = SLIST_NEXT(host, next);
1183 				free(host, M_NETGRAPH_BRIDGE);
1184 				priv->numHosts--;
1185 			} else {
1186 				if (host->age < 0xffff)
1187 					host->age++;
1188 				hptr = &SLIST_NEXT(host, next);
1189 				counter++;
1190 			}
1191 		}
1192 	}
1193 	KASSERT(priv->numHosts == counter,
1194 	    ("%s: hosts: %d != %d", __func__, priv->numHosts, counter));
1195 
1196 	/* Decrease table size if necessary */
1197 	ng_bridge_rehash(priv);
1198 
1199 	/* Decrease loop counter on muted looped back links */
1200 	counter = 0;
1201 	NG_NODE_FOREACH_HOOK(node, ng_bridge_unmute, &counter, ret);
1202 	KASSERT(priv->numLinks == counter,
1203 	    ("%s: links: %d != %d", __func__, priv->numLinks, counter));
1204 
1205 	/* Register a new timeout, keeping the existing node reference */
1206 	ng_callout(&priv->timer, node, NULL, hz, ng_bridge_timeout, NULL, 0);
1207 }
1208 
1209 /*
1210  * Return node's "name", even if it doesn't have one.
1211  */
1212 static const char *
1213 ng_bridge_nodename(node_cp node)
1214 {
1215 	static char name[NG_NODESIZ];
1216 
1217 	if (NG_NODE_HAS_NAME(node))
1218 		snprintf(name, sizeof(name), "%s", NG_NODE_NAME(node));
1219 	else
1220 		snprintf(name, sizeof(name), "[%x]", ng_node2ID(node));
1221 	return name;
1222 }
1223