xref: /freebsd/sys/netgraph/ng_bridge.c (revision af23369a6deaaeb612ab266eb88b8bb8d560c322)
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 			/* Flush all entries in the hash table */
536 			ng_bridge_remove_hosts(priv, NULL);
537 
538 			/* Reset all loop detection counters and stats */
539 			NG_NODE_FOREACH_HOOK(node, ng_bridge_reset_link, NULL);
540 			break;
541 		    }
542 		case NGM_BRIDGE_GET_STATS:
543 		case NGM_BRIDGE_CLR_STATS:
544 		case NGM_BRIDGE_GETCLR_STATS:
545 		    {
546 			hook_p hook;
547 			link_p link;
548 			char linkName[NG_HOOKSIZ];
549 			int linkNum;
550 
551 			/* Get link number */
552 			if (msg->header.arglen != sizeof(u_int32_t)) {
553 				error = EINVAL;
554 				break;
555 			}
556 			linkNum = *((int32_t *)msg->data);
557 			if (linkNum < 0)
558 				snprintf(linkName, sizeof(linkName),
559 				    "%s%u", NG_BRIDGE_HOOK_UPLINK_PREFIX, -linkNum);
560 			else
561 				snprintf(linkName, sizeof(linkName),
562 				    "%s%u", NG_BRIDGE_HOOK_LINK_PREFIX, linkNum);
563 
564 			if ((hook = ng_findhook(node, linkName)) == NULL) {
565 				error = ENOTCONN;
566 				break;
567 			}
568 			link = NG_HOOK_PRIVATE(hook);
569 
570 			/* Get/clear stats */
571 			if (msg->header.cmd != NGM_BRIDGE_CLR_STATS) {
572 				struct ng_bridge_link_stats *rs;
573 
574 				NG_MKRESPONSE(resp, msg,
575 				    sizeof(link->stats), M_NOWAIT);
576 				if (resp == NULL) {
577 					error = ENOMEM;
578 					break;
579 				}
580 				rs = (struct ng_bridge_link_stats *)resp->data;
581 #define FETCH(x)	rs->x = counter_u64_fetch(link->stats.x)
582 				FETCH(recvOctets);
583 				FETCH(recvPackets);
584 				FETCH(recvMulticasts);
585 				FETCH(recvBroadcasts);
586 				FETCH(recvUnknown);
587 				FETCH(recvRunts);
588 				FETCH(recvInvalid);
589 				FETCH(xmitOctets);
590 				FETCH(xmitPackets);
591 				FETCH(xmitMulticasts);
592 				FETCH(xmitBroadcasts);
593 				FETCH(loopDrops);
594 				rs->loopDetects = link->stats.loopDetects;
595 				FETCH(memoryFailures);
596 #undef FETCH
597 			}
598 			if (msg->header.cmd != NGM_BRIDGE_GET_STATS)
599 				ng_bridge_clear_link_stats(&link->stats);
600 			break;
601 		    }
602 		case NGM_BRIDGE_GET_TABLE:
603 		    {
604 			struct ng_bridge_host_ary *ary;
605 			struct ng_bridge_host *host;
606 			int i = 0, bucket;
607 
608 			NG_MKRESPONSE(resp, msg, sizeof(*ary)
609 			    + (priv->numHosts * sizeof(*ary->hosts)), M_NOWAIT);
610 			if (resp == NULL) {
611 				error = ENOMEM;
612 				break;
613 			}
614 			ary = (struct ng_bridge_host_ary *)resp->data;
615 			ary->numHosts = priv->numHosts;
616 			for (bucket = 0; bucket < priv->numBuckets; bucket++) {
617 				SLIST_FOREACH(host, &priv->tab[bucket], next) {
618 					memcpy(ary->hosts[i].addr,
619 					       host->addr,
620 					       sizeof(ary->hosts[i].addr));
621 					ary->hosts[i].age       = host->age;
622 					ary->hosts[i].staleness = host->staleness;
623 					strncpy(ary->hosts[i].hook,
624 						NG_HOOK_NAME(host->link->hook),
625 						sizeof(ary->hosts[i].hook));
626 					i++;
627 				}
628 			}
629 			break;
630 		    }
631 		case NGM_BRIDGE_SET_PERSISTENT:
632 		    {
633 			priv->persistent = 1;
634 			break;
635 		    }
636 		case NGM_BRIDGE_MOVE_HOST:
637 		{
638 			struct ng_bridge_move_host *mh;
639 			hook_p hook;
640 
641 			if (msg->header.arglen < sizeof(*mh)) {
642 				error = EINVAL;
643 				break;
644 			}
645 			mh = (struct ng_bridge_move_host *)msg->data;
646 			hook = (mh->hook[0] == 0)
647 			    ? lasthook
648 			    : ng_findhook(node, mh->hook);
649 			if (hook == NULL) {
650 				error = ENOENT;
651 				break;
652 			}
653 			error = ng_bridge_put(priv, mh->addr, NG_HOOK_PRIVATE(hook));
654 			break;
655 		}
656 		default:
657 			error = EINVAL;
658 			break;
659 		}
660 		break;
661 	default:
662 		error = EINVAL;
663 		break;
664 	}
665 
666 	/* Done */
667 	NG_RESPOND_MSG(error, node, item, resp);
668 	NG_FREE_MSG(msg);
669 	return (error);
670 }
671 
672 /*
673  * Receive data on a hook
674  */
675 struct ng_bridge_send_ctx {
676 	link_p foundFirst, incoming;
677 	struct mbuf * m;
678 	int manycast, error;
679 };
680 
681 /*
682  * Update stats and send out
683  */
684 static inline int
685 ng_bridge_send_data(link_cp dst, int manycast, struct mbuf *m, item_p item) {
686 	int error = 0;
687 	size_t len = m->m_pkthdr.len;
688 
689 	if(item != NULL)
690 		NG_FWD_NEW_DATA(error, item, dst->hook, m);
691 	else
692 		NG_SEND_DATA_ONLY(error, dst->hook, m);
693 
694 	if (error) {
695 		if (error == ENOMEM)
696 			counter_u64_add(dst->stats.memoryFailures, 1);
697 		/* The packet is still ours */
698 		if (item != NULL)
699 			NG_FREE_ITEM(item);
700 		if (m != NULL)
701 			NG_FREE_M(m);
702 		return (error);
703 	}
704 
705 	counter_u64_add(dst->stats.xmitPackets, 1);
706 	counter_u64_add(dst->stats.xmitOctets, len);
707 	switch (manycast) {
708 	default:		       /* unknown unicast */
709 		break;
710 	case 1:			       /* multicast */
711 		counter_u64_add(dst->stats.xmitMulticasts, 1);
712 		break;
713 	case 2:			       /* broadcast */
714 		counter_u64_add(dst->stats.xmitBroadcasts, 1);
715 		break;
716 	}
717 	return (0);
718 }
719 
720 /*
721  * Loop body for sending to multiple destinations
722  * return 0 to stop looping
723  */
724 static int
725 ng_bridge_send_ctx(hook_p dst, void *arg)
726 {
727 	struct ng_bridge_send_ctx *ctx = arg;
728 	link_p destLink = NG_HOOK_PRIVATE(dst);
729 	struct mbuf *m2 = NULL;
730 	int error = 0;
731 
732 	/* Skip incoming link */
733 	if (destLink == ctx->incoming) {
734 		return (1);
735 	}
736 
737 	/* Skip sending unknowns to undesired links  */
738 	if (!ctx->manycast && !destLink->sendUnknown)
739 		return (1);
740 
741 	if (ctx->foundFirst == NULL) {
742 		/*
743 		 * This is the first usable link we have found.
744 		 * Reserve it for the originals.
745 		 * If we never find another we save a copy.
746 		 */
747 		ctx->foundFirst = destLink;
748 		return (1);
749 	}
750 
751 	/*
752 	 * It's usable link but not the reserved (first) one.
753 	 * Copy mbuf info for sending.
754 	 */
755 	m2 = m_dup(ctx->m, M_NOWAIT);
756 	if (m2 == NULL) {
757 		counter_u64_add(ctx->incoming->stats.memoryFailures, 1);
758 		ctx->error = ENOBUFS;
759 		return (0);	       /* abort loop, do not try again and again */
760 	}
761 
762 	/* Send packet */
763 	error = ng_bridge_send_data(destLink, ctx->manycast, m2, NULL);
764 	if (error)
765 	  ctx->error = error;
766 	return (1);
767 }
768 
769 static int
770 ng_bridge_rcvdata(hook_p hook, item_p item)
771 {
772 	const node_p node = NG_HOOK_NODE(hook);
773 	const priv_p priv = NG_NODE_PRIVATE(node);
774 	struct ng_bridge_host *host;
775 	struct ether_header *eh;
776 	struct ng_bridge_send_ctx ctx = { 0 };
777 
778 	NGI_GET_M(item, ctx.m);
779 
780 	ctx.incoming = NG_HOOK_PRIVATE(hook);
781 	/* Sanity check packet and pull up header */
782 	if (ctx.m->m_pkthdr.len < ETHER_HDR_LEN) {
783 		counter_u64_add(ctx.incoming->stats.recvRunts, 1);
784 		NG_FREE_ITEM(item);
785 		NG_FREE_M(ctx.m);
786 		return (EINVAL);
787 	}
788 	if (ctx.m->m_len < ETHER_HDR_LEN && !(ctx.m = m_pullup(ctx.m, ETHER_HDR_LEN))) {
789 		counter_u64_add(ctx.incoming->stats.memoryFailures, 1);
790 		NG_FREE_ITEM(item);
791 		return (ENOBUFS);
792 	}
793 	eh = mtod(ctx.m, struct ether_header *);
794 	if ((eh->ether_shost[0] & 1) != 0) {
795 		counter_u64_add(ctx.incoming->stats.recvInvalid, 1);
796 		NG_FREE_ITEM(item);
797 		NG_FREE_M(ctx.m);
798 		return (EINVAL);
799 	}
800 
801 	/* Is link disabled due to a loopback condition? */
802 	if (ctx.incoming->loopCount != 0) {
803 		counter_u64_add(ctx.incoming->stats.loopDrops, 1);
804 		NG_FREE_ITEM(item);
805 		NG_FREE_M(ctx.m);
806 		return (ELOOP);
807 	}
808 
809 	/* Update stats */
810 	counter_u64_add(ctx.incoming->stats.recvPackets, 1);
811 	counter_u64_add(ctx.incoming->stats.recvOctets, ctx.m->m_pkthdr.len);
812 	if ((ctx.manycast = (eh->ether_dhost[0] & 1)) != 0) {
813 		if (ETHER_EQUAL(eh->ether_dhost, ng_bridge_bcast_addr)) {
814 			counter_u64_add(ctx.incoming->stats.recvBroadcasts, 1);
815 			ctx.manycast = 2;
816 		} else
817 			counter_u64_add(ctx.incoming->stats.recvMulticasts, 1);
818 	}
819 
820 	/* Look up packet's source Ethernet address in hashtable */
821 	if ((host = ng_bridge_get(priv, eh->ether_shost)) != NULL)
822 		/* Update time since last heard from this host.
823 		 * This is safe without locking, because it's
824 		 * the only operation during shared access.
825 		 */
826 		if (__predict_false(host->staleness > 0))
827 			host->staleness = 0;
828 
829 	if ((host == NULL && ctx.incoming->learnMac) ||
830 	    (host != NULL && host->link != ctx.incoming)) {
831 		struct ng_mesg *msg;
832 		struct ng_bridge_move_host *mh;
833 		int error = 0;
834 
835 		NG_MKMESSAGE(msg, NGM_BRIDGE_COOKIE, NGM_BRIDGE_MOVE_HOST,
836 		    sizeof(*mh), M_NOWAIT);
837 		if (msg == NULL) {
838 			counter_u64_add(ctx.incoming->stats.memoryFailures, 1);
839 			NG_FREE_ITEM(item);
840 			NG_FREE_M(ctx.m);
841 			return (ENOMEM);
842 		}
843 		mh = (struct ng_bridge_move_host *)msg->data;
844 		strncpy(mh->hook, NG_HOOK_NAME(ctx.incoming->hook),
845 		    sizeof(mh->hook));
846 		memcpy(mh->addr, eh->ether_shost, sizeof(mh->addr));
847 		NG_SEND_MSG_ID(error, node, msg, NG_NODE_ID(node),
848 		    NG_NODE_ID(node));
849 		if (error)
850 			counter_u64_add(ctx.incoming->stats.memoryFailures, 1);
851 	}
852 
853 	if (host != NULL && host->link != ctx.incoming) {
854 		if (host->age < priv->conf.minStableAge) {
855 			/* Drop packet on instable links */
856 			counter_u64_add(ctx.incoming->stats.loopDrops, 1);
857 			NG_FREE_ITEM(item);
858 			NG_FREE_M(ctx.m);
859 			return (ELOOP);
860 		}
861 	}
862 
863 	/* Run packet through ipfw processing, if enabled */
864 #if 0
865 	if (priv->conf.ipfw[linkNum] && V_fw_enable && V_ip_fw_chk_ptr != NULL) {
866 		/* XXX not implemented yet */
867 	}
868 #endif
869 
870 	/*
871 	 * If unicast and destination host known, deliver to host's link,
872 	 * unless it is the same link as the packet came in on.
873 	 */
874 	if (!ctx.manycast) {
875 		/* Determine packet destination link */
876 		if ((host = ng_bridge_get(priv, eh->ether_dhost)) != NULL) {
877 			link_p destLink = host->link;
878 
879 			/* If destination same as incoming link, do nothing */
880 			if (destLink == ctx.incoming) {
881 				NG_FREE_ITEM(item);
882 				NG_FREE_M(ctx.m);
883 				return (0);
884 			}
885 
886 			/* Deliver packet out the destination link */
887 			return (ng_bridge_send_data(destLink, ctx.manycast, ctx.m, item));
888 		}
889 
890 		/* Destination host is not known */
891 		counter_u64_add(ctx.incoming->stats.recvUnknown, 1);
892 	}
893 
894 	/* Distribute unknown, multicast, broadcast pkts to all other links */
895 	NG_NODE_FOREACH_HOOK(node, ng_bridge_send_ctx, &ctx);
896 
897 	/* Finally send out on the first link found */
898 	if (ctx.foundFirst != NULL) {
899 		int error = ng_bridge_send_data(ctx.foundFirst, ctx.manycast, ctx.m, item);
900 		if (error)
901 			ctx.error = error;
902 	} else {		       /* nothing to send at all */
903 		NG_FREE_ITEM(item);
904 		NG_FREE_M(ctx.m);
905 	}
906 
907 	return (ctx.error);
908 }
909 
910 /*
911  * Shutdown node
912  */
913 static int
914 ng_bridge_shutdown(node_p node)
915 {
916 	const priv_p priv = NG_NODE_PRIVATE(node);
917 
918 	/*
919 	 * Shut down everything including the timer.  Even if the
920 	 * callout has already been dequeued and is about to be
921 	 * run, ng_bridge_timeout() won't be fired as the node
922 	 * is already marked NGF_INVALID, so we're safe to free
923 	 * the node now.
924 	 */
925 	KASSERT(priv->numLinks == 0 && priv->numHosts == 0,
926 	    ("%s: numLinks=%d numHosts=%d",
927 	    __func__, priv->numLinks, priv->numHosts));
928 	ng_uncallout(&priv->timer, node);
929 	NG_NODE_SET_PRIVATE(node, NULL);
930 	NG_NODE_UNREF(node);
931 	free(priv->tab, M_NETGRAPH_BRIDGE);
932 	free(priv, M_NETGRAPH_BRIDGE);
933 	return (0);
934 }
935 
936 /*
937  * Hook disconnection.
938  */
939 static int
940 ng_bridge_disconnect(hook_p hook)
941 {
942 	const priv_p priv = NG_NODE_PRIVATE(NG_HOOK_NODE(hook));
943 	link_p link = NG_HOOK_PRIVATE(hook);
944 
945 	/* Remove all hosts associated with this link */
946 	ng_bridge_remove_hosts(priv, link);
947 
948 	/* Free associated link information */
949 	ng_bridge_free_link(link);
950 	priv->numLinks--;
951 
952 	/* If no more hooks, go away */
953 	if ((NG_NODE_NUMHOOKS(NG_HOOK_NODE(hook)) == 0)
954 	    && (NG_NODE_IS_VALID(NG_HOOK_NODE(hook)))
955 	    && !priv->persistent) {
956 		ng_rmnode_self(NG_HOOK_NODE(hook));
957 	}
958 	return (0);
959 }
960 
961 /******************************************************************
962 		    HASH TABLE FUNCTIONS
963 ******************************************************************/
964 
965 /*
966  * Hash algorithm
967  */
968 #define HASH(addr,mask)		( (((const u_int16_t *)(addr))[0] 	\
969 				 ^ ((const u_int16_t *)(addr))[1] 	\
970 				 ^ ((const u_int16_t *)(addr))[2]) & (mask) )
971 
972 /*
973  * Find a host entry in the table.
974  */
975 static struct ng_bridge_host *
976 ng_bridge_get(priv_cp priv, const u_char *addr)
977 {
978 	const int bucket = HASH(addr, priv->hashMask);
979 	struct ng_bridge_host *host;
980 
981 	SLIST_FOREACH(host, &priv->tab[bucket], next) {
982 		if (ETHER_EQUAL(host->addr, addr))
983 			return (host);
984 	}
985 	return (NULL);
986 }
987 
988 /*
989  * Add a host entry to the table. If it already exists, move it
990  * to the new link. Returns 0 on success.
991  */
992 static int
993 ng_bridge_put(priv_p priv, const u_char *addr, link_p link)
994 {
995 	const int bucket = HASH(addr, priv->hashMask);
996 	struct ng_bridge_host *host;
997 
998 	if ((host = ng_bridge_get(priv, addr)) != NULL) {
999 		/* Host already on the correct link? */
1000 		if (host->link == link)
1001 			return 0;
1002 
1003 		/* Move old host over to new link */
1004 		if (host->age >= priv->conf.minStableAge) {
1005 			host->link = link;
1006 			host->age = 0;
1007 			return (0);
1008 		}
1009 		/*
1010 		 * If the host was recently moved to the old link and
1011 		 * it's now jumping to a new link, declare a loopback
1012 		 * condition.
1013 		 */
1014 		if (priv->conf.debugLevel >= 2)
1015 		    log(LOG_WARNING, "ng_bridge: %s:"
1016 			" loopback detected on %s\n",
1017 			ng_bridge_nodename(priv->node),
1018 			NG_HOOK_NAME(link->hook));
1019 
1020 		/* Mark link as linka non grata */
1021 		link->loopCount = priv->conf.loopTimeout;
1022 		link->stats.loopDetects++;
1023 
1024 		/* Forget all hosts on this link */
1025 		ng_bridge_remove_hosts(priv, link);
1026 		return (ELOOP);
1027 	}
1028 
1029 	/* Allocate and initialize new hashtable entry */
1030 	host = malloc(sizeof(*host), M_NETGRAPH_BRIDGE, M_NOWAIT);
1031 	if (host == NULL)
1032 		return (ENOMEM);
1033 	bcopy(addr, host->addr, ETHER_ADDR_LEN);
1034 	host->link = link;
1035 	host->staleness = 0;
1036 	host->age = 0;
1037 
1038 	/* Add new element to hash bucket */
1039 	SLIST_INSERT_HEAD(&priv->tab[bucket], host, next);
1040 	priv->numHosts++;
1041 
1042 	/* Resize table if necessary */
1043 	ng_bridge_rehash(priv);
1044 	return (0);
1045 }
1046 
1047 /*
1048  * Resize the hash table. We try to maintain the number of buckets
1049  * such that the load factor is in the range 0.25 to 1.0.
1050  *
1051  * If we can't get the new memory then we silently fail. This is OK
1052  * because things will still work and we'll try again soon anyway.
1053  */
1054 static void
1055 ng_bridge_rehash(priv_p priv)
1056 {
1057 	struct ng_bridge_bucket *newTab;
1058 	int oldBucket, newBucket;
1059 	int newNumBuckets;
1060 	u_int newMask;
1061 
1062 	/* Is table too full or too empty? */
1063 	if (priv->numHosts > priv->numBuckets
1064 	    && (priv->numBuckets << 1) <= MAX_BUCKETS)
1065 		newNumBuckets = priv->numBuckets << 1;
1066 	else if (priv->numHosts < (priv->numBuckets >> 2)
1067 	    && (priv->numBuckets >> 2) >= MIN_BUCKETS)
1068 		newNumBuckets = priv->numBuckets >> 2;
1069 	else
1070 		return;
1071 	newMask = newNumBuckets - 1;
1072 
1073 	/* Allocate and initialize new table */
1074 	newTab = malloc(newNumBuckets * sizeof(*newTab),
1075 	    M_NETGRAPH_BRIDGE, M_NOWAIT | M_ZERO);
1076 	if (newTab == NULL)
1077 		return;
1078 
1079 	/* Move all entries from old table to new table */
1080 	for (oldBucket = 0; oldBucket < priv->numBuckets; oldBucket++) {
1081 		struct ng_bridge_bucket *const oldList = &priv->tab[oldBucket];
1082 
1083 		while (!SLIST_EMPTY(oldList)) {
1084 			struct ng_bridge_host *const host
1085 			    = SLIST_FIRST(oldList);
1086 
1087 			SLIST_REMOVE_HEAD(oldList, next);
1088 			newBucket = HASH(host->addr, newMask);
1089 			SLIST_INSERT_HEAD(&newTab[newBucket], host, next);
1090 		}
1091 	}
1092 
1093 	/* Replace old table with new one */
1094 	if (priv->conf.debugLevel >= 3) {
1095 		log(LOG_INFO, "ng_bridge: %s: table size %d -> %d\n",
1096 		    ng_bridge_nodename(priv->node),
1097 		    priv->numBuckets, newNumBuckets);
1098 	}
1099 	free(priv->tab, M_NETGRAPH_BRIDGE);
1100 	priv->numBuckets = newNumBuckets;
1101 	priv->hashMask = newMask;
1102 	priv->tab = newTab;
1103 	return;
1104 }
1105 
1106 /******************************************************************
1107 		    MISC FUNCTIONS
1108 ******************************************************************/
1109 
1110 /*
1111  * Remove all hosts associated with a specific link from the hashtable.
1112  * If linkNum == -1, then remove all hosts in the table.
1113  */
1114 static void
1115 ng_bridge_remove_hosts(priv_p priv, link_p link)
1116 {
1117 	int bucket;
1118 
1119 	for (bucket = 0; bucket < priv->numBuckets; bucket++) {
1120 		struct ng_bridge_host **hptr = &SLIST_FIRST(&priv->tab[bucket]);
1121 
1122 		while (*hptr != NULL) {
1123 			struct ng_bridge_host *const host = *hptr;
1124 
1125 			if (link == NULL || host->link == link) {
1126 				*hptr = SLIST_NEXT(host, next);
1127 				free(host, M_NETGRAPH_BRIDGE);
1128 				priv->numHosts--;
1129 			} else
1130 				hptr = &SLIST_NEXT(host, next);
1131 		}
1132 	}
1133 }
1134 
1135 /*
1136  * Handle our once-per-second timeout event. We do two things:
1137  * we decrement link->loopCount for those links being muted due to
1138  * a detected loopback condition, and we remove any hosts from
1139  * the hashtable whom we haven't heard from in a long while.
1140  */
1141 static int
1142 ng_bridge_unmute(hook_p hook, void *arg)
1143 {
1144 	link_p link = NG_HOOK_PRIVATE(hook);
1145 	node_p node = NG_HOOK_NODE(hook);
1146 	priv_p priv = NG_NODE_PRIVATE(node);
1147 	int *counter = arg;
1148 
1149 	if (link->loopCount != 0) {
1150 		link->loopCount--;
1151 		if (link->loopCount == 0 && priv->conf.debugLevel >= 2) {
1152 			log(LOG_INFO, "ng_bridge: %s:"
1153 			    " restoring looped back %s\n",
1154 			    ng_bridge_nodename(node), NG_HOOK_NAME(hook));
1155 		}
1156 	}
1157 	(*counter)++;
1158 	return (1);
1159 }
1160 
1161 static void
1162 ng_bridge_timeout(node_p node, hook_p hook, void *arg1, int arg2)
1163 {
1164 	const priv_p priv = NG_NODE_PRIVATE(node);
1165 	int bucket;
1166 	int counter = 0;
1167 
1168 	/* Update host time counters and remove stale entries */
1169 	for (bucket = 0; bucket < priv->numBuckets; bucket++) {
1170 		struct ng_bridge_host **hptr = &SLIST_FIRST(&priv->tab[bucket]);
1171 
1172 		while (*hptr != NULL) {
1173 			struct ng_bridge_host *const host = *hptr;
1174 
1175 			/* Remove hosts we haven't heard from in a while */
1176 			if (++host->staleness >= priv->conf.maxStaleness) {
1177 				*hptr = SLIST_NEXT(host, next);
1178 				free(host, M_NETGRAPH_BRIDGE);
1179 				priv->numHosts--;
1180 			} else {
1181 				if (host->age < 0xffff)
1182 					host->age++;
1183 				hptr = &SLIST_NEXT(host, next);
1184 				counter++;
1185 			}
1186 		}
1187 	}
1188 	KASSERT(priv->numHosts == counter,
1189 	    ("%s: hosts: %d != %d", __func__, priv->numHosts, counter));
1190 
1191 	/* Decrease table size if necessary */
1192 	ng_bridge_rehash(priv);
1193 
1194 	/* Decrease loop counter on muted looped back links */
1195 	counter = 0;
1196 	NG_NODE_FOREACH_HOOK(node, ng_bridge_unmute, &counter);
1197 	KASSERT(priv->numLinks == counter,
1198 	    ("%s: links: %d != %d", __func__, priv->numLinks, counter));
1199 
1200 	/* Register a new timeout, keeping the existing node reference */
1201 	ng_callout(&priv->timer, node, NULL, hz, ng_bridge_timeout, NULL, 0);
1202 }
1203 
1204 /*
1205  * Return node's "name", even if it doesn't have one.
1206  */
1207 static const char *
1208 ng_bridge_nodename(node_cp node)
1209 {
1210 	static char name[NG_NODESIZ];
1211 
1212 	if (NG_NODE_HAS_NAME(node))
1213 		snprintf(name, sizeof(name), "%s", NG_NODE_NAME(node));
1214 	else
1215 		snprintf(name, sizeof(name), "[%x]", ng_node2ID(node));
1216 	return name;
1217 }
1218