xref: /freebsd/sys/netgraph/ng_base.c (revision 4c8945a06b01a5c8122cdeb402af36bb46a06acc)
1 /*
2  * ng_base.c
3  */
4 
5 /*-
6  * Copyright (c) 1996-1999 Whistle Communications, Inc.
7  * All rights reserved.
8  *
9  * Subject to the following obligations and disclaimer of warranty, use and
10  * redistribution of this software, in source or object code forms, with or
11  * without modifications are expressly permitted by Whistle Communications;
12  * provided, however, that:
13  * 1. Any and all reproductions of the source or object code must include the
14  *    copyright notice above and the following disclaimer of warranties; and
15  * 2. No rights are granted, in any manner or form, to use Whistle
16  *    Communications, Inc. trademarks, including the mark "WHISTLE
17  *    COMMUNICATIONS" on advertising, endorsements, or otherwise except as
18  *    such appears in the above copyright notice or in the software.
19  *
20  * THIS SOFTWARE IS BEING PROVIDED BY WHISTLE COMMUNICATIONS "AS IS", AND
21  * TO THE MAXIMUM EXTENT PERMITTED BY LAW, WHISTLE COMMUNICATIONS MAKES NO
22  * REPRESENTATIONS OR WARRANTIES, EXPRESS OR IMPLIED, REGARDING THIS SOFTWARE,
23  * INCLUDING WITHOUT LIMITATION, ANY AND ALL IMPLIED WARRANTIES OF
24  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, OR NON-INFRINGEMENT.
25  * WHISTLE COMMUNICATIONS DOES NOT WARRANT, GUARANTEE, OR MAKE ANY
26  * REPRESENTATIONS REGARDING THE USE OF, OR THE RESULTS OF THE USE OF THIS
27  * SOFTWARE IN TERMS OF ITS CORRECTNESS, ACCURACY, RELIABILITY OR OTHERWISE.
28  * IN NO EVENT SHALL WHISTLE COMMUNICATIONS BE LIABLE FOR ANY DAMAGES
29  * RESULTING FROM OR ARISING OUT OF ANY USE OF THIS SOFTWARE, INCLUDING
30  * WITHOUT LIMITATION, ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY,
31  * PUNITIVE, OR CONSEQUENTIAL DAMAGES, PROCUREMENT OF SUBSTITUTE GOODS OR
32  * SERVICES, LOSS OF USE, DATA OR PROFITS, HOWEVER CAUSED AND UNDER ANY
33  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
34  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
35  * THIS SOFTWARE, EVEN IF WHISTLE COMMUNICATIONS IS ADVISED OF THE POSSIBILITY
36  * OF SUCH DAMAGE.
37  *
38  * Authors: Julian Elischer <julian@freebsd.org>
39  *          Archie Cobbs <archie@freebsd.org>
40  *
41  * $FreeBSD$
42  * $Whistle: ng_base.c,v 1.39 1999/01/28 23:54:53 julian Exp $
43  */
44 
45 /*
46  * This file implements the base netgraph code.
47  */
48 
49 #include <sys/param.h>
50 #include <sys/systm.h>
51 #include <sys/ctype.h>
52 #include <sys/errno.h>
53 #include <sys/kdb.h>
54 #include <sys/kernel.h>
55 #include <sys/ktr.h>
56 #include <sys/limits.h>
57 #include <sys/malloc.h>
58 #include <sys/mbuf.h>
59 #include <sys/queue.h>
60 #include <sys/sysctl.h>
61 #include <sys/syslog.h>
62 #include <sys/refcount.h>
63 #include <sys/proc.h>
64 #include <sys/unistd.h>
65 #include <sys/kthread.h>
66 #include <sys/smp.h>
67 #include <machine/cpu.h>
68 
69 #include <net/netisr.h>
70 #include <net/vnet.h>
71 
72 #include <netgraph/ng_message.h>
73 #include <netgraph/netgraph.h>
74 #include <netgraph/ng_parse.h>
75 
76 MODULE_VERSION(netgraph, NG_ABI_VERSION);
77 
78 /* Mutex to protect topology events. */
79 static struct mtx	ng_topo_mtx;
80 
81 #ifdef	NETGRAPH_DEBUG
82 static struct mtx	ng_nodelist_mtx; /* protects global node/hook lists */
83 static struct mtx	ngq_mtx;	/* protects the queue item list */
84 
85 static SLIST_HEAD(, ng_node) ng_allnodes;
86 static LIST_HEAD(, ng_node) ng_freenodes; /* in debug, we never free() them */
87 static SLIST_HEAD(, ng_hook) ng_allhooks;
88 static LIST_HEAD(, ng_hook) ng_freehooks; /* in debug, we never free() them */
89 
90 static void ng_dumpitems(void);
91 static void ng_dumpnodes(void);
92 static void ng_dumphooks(void);
93 
94 #endif	/* NETGRAPH_DEBUG */
95 /*
96  * DEAD versions of the structures.
97  * In order to avoid races, it is sometimes neccesary to point
98  * at SOMETHING even though theoretically, the current entity is
99  * INVALID. Use these to avoid these races.
100  */
101 struct ng_type ng_deadtype = {
102 	NG_ABI_VERSION,
103 	"dead",
104 	NULL,	/* modevent */
105 	NULL,	/* constructor */
106 	NULL,	/* rcvmsg */
107 	NULL,	/* shutdown */
108 	NULL,	/* newhook */
109 	NULL,	/* findhook */
110 	NULL,	/* connect */
111 	NULL,	/* rcvdata */
112 	NULL,	/* disconnect */
113 	NULL, 	/* cmdlist */
114 };
115 
116 struct ng_node ng_deadnode = {
117 	"dead",
118 	&ng_deadtype,
119 	NGF_INVALID,
120 	0,	/* numhooks */
121 	NULL,	/* private */
122 	0,	/* ID */
123 	LIST_HEAD_INITIALIZER(ng_deadnode.nd_hooks),
124 	{},	/* all_nodes list entry */
125 	{},	/* id hashtable list entry */
126 	{	0,
127 		0,
128 		{}, /* should never use! (should hang) */
129 		{}, /* workqueue entry */
130 		STAILQ_HEAD_INITIALIZER(ng_deadnode.nd_input_queue.queue),
131 	},
132 	1,	/* refs */
133 	NULL,	/* vnet */
134 #ifdef	NETGRAPH_DEBUG
135 	ND_MAGIC,
136 	__FILE__,
137 	__LINE__,
138 	{NULL}
139 #endif	/* NETGRAPH_DEBUG */
140 };
141 
142 struct ng_hook ng_deadhook = {
143 	"dead",
144 	NULL,		/* private */
145 	HK_INVALID | HK_DEAD,
146 	0,		/* undefined data link type */
147 	&ng_deadhook,	/* Peer is self */
148 	&ng_deadnode,	/* attached to deadnode */
149 	{},		/* hooks list */
150 	NULL,		/* override rcvmsg() */
151 	NULL,		/* override rcvdata() */
152 	1,		/* refs always >= 1 */
153 #ifdef	NETGRAPH_DEBUG
154 	HK_MAGIC,
155 	__FILE__,
156 	__LINE__,
157 	{NULL}
158 #endif	/* NETGRAPH_DEBUG */
159 };
160 
161 /*
162  * END DEAD STRUCTURES
163  */
164 /* List nodes with unallocated work */
165 static STAILQ_HEAD(, ng_node) ng_worklist = STAILQ_HEAD_INITIALIZER(ng_worklist);
166 static struct mtx	ng_worklist_mtx;   /* MUST LOCK NODE FIRST */
167 
168 /* List of installed types */
169 static LIST_HEAD(, ng_type) ng_typelist;
170 static struct mtx	ng_typelist_mtx;
171 
172 /* Hash related definitions */
173 /* XXX Don't need to initialise them because it's a LIST */
174 static VNET_DEFINE(LIST_HEAD(, ng_node), ng_ID_hash[NG_ID_HASH_SIZE]);
175 #define	V_ng_ID_hash			VNET(ng_ID_hash)
176 
177 static struct mtx	ng_idhash_mtx;
178 /* Method to find a node.. used twice so do it here */
179 #define NG_IDHASH_FN(ID) ((ID) % (NG_ID_HASH_SIZE))
180 #define NG_IDHASH_FIND(ID, node)					\
181 	do { 								\
182 		mtx_assert(&ng_idhash_mtx, MA_OWNED);			\
183 		LIST_FOREACH(node, &V_ng_ID_hash[NG_IDHASH_FN(ID)],	\
184 						nd_idnodes) {		\
185 			if (NG_NODE_IS_VALID(node)			\
186 			&& (NG_NODE_ID(node) == ID)) {			\
187 				break;					\
188 			}						\
189 		}							\
190 	} while (0)
191 
192 static VNET_DEFINE(LIST_HEAD(, ng_node), ng_name_hash[NG_NAME_HASH_SIZE]);
193 #define	V_ng_name_hash			VNET(ng_name_hash)
194 
195 static struct mtx	ng_namehash_mtx;
196 #define NG_NAMEHASH(NAME, HASH)				\
197 	do {						\
198 		u_char	h = 0;				\
199 		const u_char	*c;			\
200 		for (c = (const u_char*)(NAME); *c; c++)\
201 			h += *c;			\
202 		(HASH) = h % (NG_NAME_HASH_SIZE);	\
203 	} while (0)
204 
205 
206 /* Internal functions */
207 static int	ng_add_hook(node_p node, const char *name, hook_p * hookp);
208 static int	ng_generic_msg(node_p here, item_p item, hook_p lasthook);
209 static ng_ID_t	ng_decodeidname(const char *name);
210 static int	ngb_mod_event(module_t mod, int event, void *data);
211 static void	ng_worklist_add(node_p node);
212 static void	ngthread(void *);
213 static int	ng_apply_item(node_p node, item_p item, int rw);
214 static void	ng_flush_input_queue(node_p node);
215 static node_p	ng_ID2noderef(ng_ID_t ID);
216 static int	ng_con_nodes(item_p item, node_p node, const char *name,
217 		    node_p node2, const char *name2);
218 static int	ng_con_part2(node_p node, item_p item, hook_p hook);
219 static int	ng_con_part3(node_p node, item_p item, hook_p hook);
220 static int	ng_mkpeer(node_p node, const char *name,
221 						const char *name2, char *type);
222 
223 /* Imported, these used to be externally visible, some may go back. */
224 void	ng_destroy_hook(hook_p hook);
225 int	ng_path2noderef(node_p here, const char *path,
226 	node_p *dest, hook_p *lasthook);
227 int	ng_make_node(const char *type, node_p *nodepp);
228 int	ng_path_parse(char *addr, char **node, char **path, char **hook);
229 void	ng_rmnode(node_p node, hook_p dummy1, void *dummy2, int dummy3);
230 void	ng_unname(node_p node);
231 
232 
233 /* Our own netgraph malloc type */
234 MALLOC_DEFINE(M_NETGRAPH, "netgraph", "netgraph structures and ctrl messages");
235 MALLOC_DEFINE(M_NETGRAPH_HOOK, "netgraph_hook", "netgraph hook structures");
236 MALLOC_DEFINE(M_NETGRAPH_NODE, "netgraph_node", "netgraph node structures");
237 MALLOC_DEFINE(M_NETGRAPH_ITEM, "netgraph_item", "netgraph item structures");
238 MALLOC_DEFINE(M_NETGRAPH_MSG, "netgraph_msg", "netgraph name storage");
239 
240 /* Should not be visible outside this file */
241 
242 #define _NG_ALLOC_HOOK(hook) \
243 	hook = malloc(sizeof(*hook), M_NETGRAPH_HOOK, M_NOWAIT | M_ZERO)
244 #define _NG_ALLOC_NODE(node) \
245 	node = malloc(sizeof(*node), M_NETGRAPH_NODE, M_NOWAIT | M_ZERO)
246 
247 #define	NG_QUEUE_LOCK_INIT(n)			\
248 	mtx_init(&(n)->q_mtx, "ng_node", NULL, MTX_DEF)
249 #define	NG_QUEUE_LOCK(n)			\
250 	mtx_lock(&(n)->q_mtx)
251 #define	NG_QUEUE_UNLOCK(n)			\
252 	mtx_unlock(&(n)->q_mtx)
253 #define	NG_WORKLIST_LOCK_INIT()			\
254 	mtx_init(&ng_worklist_mtx, "ng_worklist", NULL, MTX_DEF)
255 #define	NG_WORKLIST_LOCK()			\
256 	mtx_lock(&ng_worklist_mtx)
257 #define	NG_WORKLIST_UNLOCK()			\
258 	mtx_unlock(&ng_worklist_mtx)
259 #define	NG_WORKLIST_SLEEP()			\
260 	mtx_sleep(&ng_worklist, &ng_worklist_mtx, PI_NET, "sleep", 0)
261 #define	NG_WORKLIST_WAKEUP()			\
262 	wakeup_one(&ng_worklist)
263 
264 #ifdef NETGRAPH_DEBUG /*----------------------------------------------*/
265 /*
266  * In debug mode:
267  * In an attempt to help track reference count screwups
268  * we do not free objects back to the malloc system, but keep them
269  * in a local cache where we can examine them and keep information safely
270  * after they have been freed.
271  * We use this scheme for nodes and hooks, and to some extent for items.
272  */
273 static __inline hook_p
274 ng_alloc_hook(void)
275 {
276 	hook_p hook;
277 	SLIST_ENTRY(ng_hook) temp;
278 	mtx_lock(&ng_nodelist_mtx);
279 	hook = LIST_FIRST(&ng_freehooks);
280 	if (hook) {
281 		LIST_REMOVE(hook, hk_hooks);
282 		bcopy(&hook->hk_all, &temp, sizeof(temp));
283 		bzero(hook, sizeof(struct ng_hook));
284 		bcopy(&temp, &hook->hk_all, sizeof(temp));
285 		mtx_unlock(&ng_nodelist_mtx);
286 		hook->hk_magic = HK_MAGIC;
287 	} else {
288 		mtx_unlock(&ng_nodelist_mtx);
289 		_NG_ALLOC_HOOK(hook);
290 		if (hook) {
291 			hook->hk_magic = HK_MAGIC;
292 			mtx_lock(&ng_nodelist_mtx);
293 			SLIST_INSERT_HEAD(&ng_allhooks, hook, hk_all);
294 			mtx_unlock(&ng_nodelist_mtx);
295 		}
296 	}
297 	return (hook);
298 }
299 
300 static __inline node_p
301 ng_alloc_node(void)
302 {
303 	node_p node;
304 	SLIST_ENTRY(ng_node) temp;
305 	mtx_lock(&ng_nodelist_mtx);
306 	node = LIST_FIRST(&ng_freenodes);
307 	if (node) {
308 		LIST_REMOVE(node, nd_nodes);
309 		bcopy(&node->nd_all, &temp, sizeof(temp));
310 		bzero(node, sizeof(struct ng_node));
311 		bcopy(&temp, &node->nd_all, sizeof(temp));
312 		mtx_unlock(&ng_nodelist_mtx);
313 		node->nd_magic = ND_MAGIC;
314 	} else {
315 		mtx_unlock(&ng_nodelist_mtx);
316 		_NG_ALLOC_NODE(node);
317 		if (node) {
318 			node->nd_magic = ND_MAGIC;
319 			mtx_lock(&ng_nodelist_mtx);
320 			SLIST_INSERT_HEAD(&ng_allnodes, node, nd_all);
321 			mtx_unlock(&ng_nodelist_mtx);
322 		}
323 	}
324 	return (node);
325 }
326 
327 #define NG_ALLOC_HOOK(hook) do { (hook) = ng_alloc_hook(); } while (0)
328 #define NG_ALLOC_NODE(node) do { (node) = ng_alloc_node(); } while (0)
329 
330 
331 #define NG_FREE_HOOK(hook)						\
332 	do {								\
333 		mtx_lock(&ng_nodelist_mtx);			\
334 		LIST_INSERT_HEAD(&ng_freehooks, hook, hk_hooks);	\
335 		hook->hk_magic = 0;					\
336 		mtx_unlock(&ng_nodelist_mtx);			\
337 	} while (0)
338 
339 #define NG_FREE_NODE(node)						\
340 	do {								\
341 		mtx_lock(&ng_nodelist_mtx);			\
342 		LIST_INSERT_HEAD(&ng_freenodes, node, nd_nodes);	\
343 		node->nd_magic = 0;					\
344 		mtx_unlock(&ng_nodelist_mtx);			\
345 	} while (0)
346 
347 #else /* NETGRAPH_DEBUG */ /*----------------------------------------------*/
348 
349 #define NG_ALLOC_HOOK(hook) _NG_ALLOC_HOOK(hook)
350 #define NG_ALLOC_NODE(node) _NG_ALLOC_NODE(node)
351 
352 #define NG_FREE_HOOK(hook) do { free((hook), M_NETGRAPH_HOOK); } while (0)
353 #define NG_FREE_NODE(node) do { free((node), M_NETGRAPH_NODE); } while (0)
354 
355 #endif /* NETGRAPH_DEBUG */ /*----------------------------------------------*/
356 
357 /* Set this to kdb_enter("X") to catch all errors as they occur */
358 #ifndef TRAP_ERROR
359 #define TRAP_ERROR()
360 #endif
361 
362 static VNET_DEFINE(ng_ID_t, nextID) = 1;
363 #define	V_nextID			VNET(nextID)
364 
365 #ifdef INVARIANTS
366 #define CHECK_DATA_MBUF(m)	do {					\
367 		struct mbuf *n;						\
368 		int total;						\
369 									\
370 		M_ASSERTPKTHDR(m);					\
371 		for (total = 0, n = (m); n != NULL; n = n->m_next) {	\
372 			total += n->m_len;				\
373 			if (n->m_nextpkt != NULL)			\
374 				panic("%s: m_nextpkt", __func__);	\
375 		}							\
376 									\
377 		if ((m)->m_pkthdr.len != total) {			\
378 			panic("%s: %d != %d",				\
379 			    __func__, (m)->m_pkthdr.len, total);	\
380 		}							\
381 	} while (0)
382 #else
383 #define CHECK_DATA_MBUF(m)
384 #endif
385 
386 #define ERROUT(x)	do { error = (x); goto done; } while (0)
387 
388 /************************************************************************
389 	Parse type definitions for generic messages
390 ************************************************************************/
391 
392 /* Handy structure parse type defining macro */
393 #define DEFINE_PARSE_STRUCT_TYPE(lo, up, args)				\
394 static const struct ng_parse_struct_field				\
395 	ng_ ## lo ## _type_fields[] = NG_GENERIC_ ## up ## _INFO args;	\
396 static const struct ng_parse_type ng_generic_ ## lo ## _type = {	\
397 	&ng_parse_struct_type,						\
398 	&ng_ ## lo ## _type_fields					\
399 }
400 
401 DEFINE_PARSE_STRUCT_TYPE(mkpeer, MKPEER, ());
402 DEFINE_PARSE_STRUCT_TYPE(connect, CONNECT, ());
403 DEFINE_PARSE_STRUCT_TYPE(name, NAME, ());
404 DEFINE_PARSE_STRUCT_TYPE(rmhook, RMHOOK, ());
405 DEFINE_PARSE_STRUCT_TYPE(nodeinfo, NODEINFO, ());
406 DEFINE_PARSE_STRUCT_TYPE(typeinfo, TYPEINFO, ());
407 DEFINE_PARSE_STRUCT_TYPE(linkinfo, LINKINFO, (&ng_generic_nodeinfo_type));
408 
409 /* Get length of an array when the length is stored as a 32 bit
410    value immediately preceding the array -- as with struct namelist
411    and struct typelist. */
412 static int
413 ng_generic_list_getLength(const struct ng_parse_type *type,
414 	const u_char *start, const u_char *buf)
415 {
416 	return *((const u_int32_t *)(buf - 4));
417 }
418 
419 /* Get length of the array of struct linkinfo inside a struct hooklist */
420 static int
421 ng_generic_linkinfo_getLength(const struct ng_parse_type *type,
422 	const u_char *start, const u_char *buf)
423 {
424 	const struct hooklist *hl = (const struct hooklist *)start;
425 
426 	return hl->nodeinfo.hooks;
427 }
428 
429 /* Array type for a variable length array of struct namelist */
430 static const struct ng_parse_array_info ng_nodeinfoarray_type_info = {
431 	&ng_generic_nodeinfo_type,
432 	&ng_generic_list_getLength
433 };
434 static const struct ng_parse_type ng_generic_nodeinfoarray_type = {
435 	&ng_parse_array_type,
436 	&ng_nodeinfoarray_type_info
437 };
438 
439 /* Array type for a variable length array of struct typelist */
440 static const struct ng_parse_array_info ng_typeinfoarray_type_info = {
441 	&ng_generic_typeinfo_type,
442 	&ng_generic_list_getLength
443 };
444 static const struct ng_parse_type ng_generic_typeinfoarray_type = {
445 	&ng_parse_array_type,
446 	&ng_typeinfoarray_type_info
447 };
448 
449 /* Array type for array of struct linkinfo in struct hooklist */
450 static const struct ng_parse_array_info ng_generic_linkinfo_array_type_info = {
451 	&ng_generic_linkinfo_type,
452 	&ng_generic_linkinfo_getLength
453 };
454 static const struct ng_parse_type ng_generic_linkinfo_array_type = {
455 	&ng_parse_array_type,
456 	&ng_generic_linkinfo_array_type_info
457 };
458 
459 DEFINE_PARSE_STRUCT_TYPE(typelist, TYPELIST, (&ng_generic_nodeinfoarray_type));
460 DEFINE_PARSE_STRUCT_TYPE(hooklist, HOOKLIST,
461 	(&ng_generic_nodeinfo_type, &ng_generic_linkinfo_array_type));
462 DEFINE_PARSE_STRUCT_TYPE(listnodes, LISTNODES,
463 	(&ng_generic_nodeinfoarray_type));
464 
465 /* List of commands and how to convert arguments to/from ASCII */
466 static const struct ng_cmdlist ng_generic_cmds[] = {
467 	{
468 	  NGM_GENERIC_COOKIE,
469 	  NGM_SHUTDOWN,
470 	  "shutdown",
471 	  NULL,
472 	  NULL
473 	},
474 	{
475 	  NGM_GENERIC_COOKIE,
476 	  NGM_MKPEER,
477 	  "mkpeer",
478 	  &ng_generic_mkpeer_type,
479 	  NULL
480 	},
481 	{
482 	  NGM_GENERIC_COOKIE,
483 	  NGM_CONNECT,
484 	  "connect",
485 	  &ng_generic_connect_type,
486 	  NULL
487 	},
488 	{
489 	  NGM_GENERIC_COOKIE,
490 	  NGM_NAME,
491 	  "name",
492 	  &ng_generic_name_type,
493 	  NULL
494 	},
495 	{
496 	  NGM_GENERIC_COOKIE,
497 	  NGM_RMHOOK,
498 	  "rmhook",
499 	  &ng_generic_rmhook_type,
500 	  NULL
501 	},
502 	{
503 	  NGM_GENERIC_COOKIE,
504 	  NGM_NODEINFO,
505 	  "nodeinfo",
506 	  NULL,
507 	  &ng_generic_nodeinfo_type
508 	},
509 	{
510 	  NGM_GENERIC_COOKIE,
511 	  NGM_LISTHOOKS,
512 	  "listhooks",
513 	  NULL,
514 	  &ng_generic_hooklist_type
515 	},
516 	{
517 	  NGM_GENERIC_COOKIE,
518 	  NGM_LISTNAMES,
519 	  "listnames",
520 	  NULL,
521 	  &ng_generic_listnodes_type	/* same as NGM_LISTNODES */
522 	},
523 	{
524 	  NGM_GENERIC_COOKIE,
525 	  NGM_LISTNODES,
526 	  "listnodes",
527 	  NULL,
528 	  &ng_generic_listnodes_type
529 	},
530 	{
531 	  NGM_GENERIC_COOKIE,
532 	  NGM_LISTTYPES,
533 	  "listtypes",
534 	  NULL,
535 	  &ng_generic_typeinfo_type
536 	},
537 	{
538 	  NGM_GENERIC_COOKIE,
539 	  NGM_TEXT_CONFIG,
540 	  "textconfig",
541 	  NULL,
542 	  &ng_parse_string_type
543 	},
544 	{
545 	  NGM_GENERIC_COOKIE,
546 	  NGM_TEXT_STATUS,
547 	  "textstatus",
548 	  NULL,
549 	  &ng_parse_string_type
550 	},
551 	{
552 	  NGM_GENERIC_COOKIE,
553 	  NGM_ASCII2BINARY,
554 	  "ascii2binary",
555 	  &ng_parse_ng_mesg_type,
556 	  &ng_parse_ng_mesg_type
557 	},
558 	{
559 	  NGM_GENERIC_COOKIE,
560 	  NGM_BINARY2ASCII,
561 	  "binary2ascii",
562 	  &ng_parse_ng_mesg_type,
563 	  &ng_parse_ng_mesg_type
564 	},
565 	{ 0 }
566 };
567 
568 /************************************************************************
569 			Node routines
570 ************************************************************************/
571 
572 /*
573  * Instantiate a node of the requested type
574  */
575 int
576 ng_make_node(const char *typename, node_p *nodepp)
577 {
578 	struct ng_type *type;
579 	int	error;
580 
581 	/* Check that the type makes sense */
582 	if (typename == NULL) {
583 		TRAP_ERROR();
584 		return (EINVAL);
585 	}
586 
587 	/* Locate the node type. If we fail we return. Do not try to load
588 	 * module.
589 	 */
590 	if ((type = ng_findtype(typename)) == NULL)
591 		return (ENXIO);
592 
593 	/*
594 	 * If we have a constructor, then make the node and
595 	 * call the constructor to do type specific initialisation.
596 	 */
597 	if (type->constructor != NULL) {
598 		if ((error = ng_make_node_common(type, nodepp)) == 0) {
599 			if ((error = ((*type->constructor)(*nodepp)) != 0)) {
600 				NG_NODE_UNREF(*nodepp);
601 			}
602 		}
603 	} else {
604 		/*
605 		 * Node has no constructor. We cannot ask for one
606 		 * to be made. It must be brought into existence by
607 		 * some external agency. The external agency should
608 		 * call ng_make_node_common() directly to get the
609 		 * netgraph part initialised.
610 		 */
611 		TRAP_ERROR();
612 		error = EINVAL;
613 	}
614 	return (error);
615 }
616 
617 /*
618  * Generic node creation. Called by node initialisation for externally
619  * instantiated nodes (e.g. hardware, sockets, etc ).
620  * The returned node has a reference count of 1.
621  */
622 int
623 ng_make_node_common(struct ng_type *type, node_p *nodepp)
624 {
625 	node_p node;
626 
627 	/* Require the node type to have been already installed */
628 	if (ng_findtype(type->name) == NULL) {
629 		TRAP_ERROR();
630 		return (EINVAL);
631 	}
632 
633 	/* Make a node and try attach it to the type */
634 	NG_ALLOC_NODE(node);
635 	if (node == NULL) {
636 		TRAP_ERROR();
637 		return (ENOMEM);
638 	}
639 	node->nd_type = type;
640 #ifdef VIMAGE
641 	node->nd_vnet = curvnet;
642 #endif
643 	NG_NODE_REF(node);				/* note reference */
644 	type->refs++;
645 
646 	NG_QUEUE_LOCK_INIT(&node->nd_input_queue);
647 	STAILQ_INIT(&node->nd_input_queue.queue);
648 	node->nd_input_queue.q_flags = 0;
649 
650 	/* Initialize hook list for new node */
651 	LIST_INIT(&node->nd_hooks);
652 
653 	/* Link us into the name hash. */
654 	mtx_lock(&ng_namehash_mtx);
655 	LIST_INSERT_HEAD(&V_ng_name_hash[0], node, nd_nodes);
656 	mtx_unlock(&ng_namehash_mtx);
657 
658 	/* get an ID and put us in the hash chain */
659 	mtx_lock(&ng_idhash_mtx);
660 	for (;;) { /* wrap protection, even if silly */
661 		node_p node2 = NULL;
662 		node->nd_ID = V_nextID++; /* 137/sec for 1 year before wrap */
663 
664 		/* Is there a problem with the new number? */
665 		NG_IDHASH_FIND(node->nd_ID, node2); /* already taken? */
666 		if ((node->nd_ID != 0) && (node2 == NULL)) {
667 			break;
668 		}
669 	}
670 	LIST_INSERT_HEAD(&V_ng_ID_hash[NG_IDHASH_FN(node->nd_ID)],
671 							node, nd_idnodes);
672 	mtx_unlock(&ng_idhash_mtx);
673 
674 	/* Done */
675 	*nodepp = node;
676 	return (0);
677 }
678 
679 /*
680  * Forceably start the shutdown process on a node. Either call
681  * its shutdown method, or do the default shutdown if there is
682  * no type-specific method.
683  *
684  * We can only be called from a shutdown message, so we know we have
685  * a writer lock, and therefore exclusive access. It also means
686  * that we should not be on the work queue, but we check anyhow.
687  *
688  * Persistent node types must have a type-specific method which
689  * allocates a new node in which case, this one is irretrievably going away,
690  * or cleans up anything it needs, and just makes the node valid again,
691  * in which case we allow the node to survive.
692  *
693  * XXX We need to think of how to tell a persistent node that we
694  * REALLY need to go away because the hardware has gone or we
695  * are rebooting.... etc.
696  */
697 void
698 ng_rmnode(node_p node, hook_p dummy1, void *dummy2, int dummy3)
699 {
700 	hook_p hook;
701 
702 	/* Check if it's already shutting down */
703 	if ((node->nd_flags & NGF_CLOSING) != 0)
704 		return;
705 
706 	if (node == &ng_deadnode) {
707 		printf ("shutdown called on deadnode\n");
708 		return;
709 	}
710 
711 	/* Add an extra reference so it doesn't go away during this */
712 	NG_NODE_REF(node);
713 
714 	/*
715 	 * Mark it invalid so any newcomers know not to try use it
716 	 * Also add our own mark so we can't recurse
717 	 * note that NGF_INVALID does not do this as it's also set during
718 	 * creation
719 	 */
720 	node->nd_flags |= NGF_INVALID|NGF_CLOSING;
721 
722 	/* If node has its pre-shutdown method, then call it first*/
723 	if (node->nd_type && node->nd_type->close)
724 		(*node->nd_type->close)(node);
725 
726 	/* Notify all remaining connected nodes to disconnect */
727 	while ((hook = LIST_FIRST(&node->nd_hooks)) != NULL)
728 		ng_destroy_hook(hook);
729 
730 	/*
731 	 * Drain the input queue forceably.
732 	 * it has no hooks so what's it going to do, bleed on someone?
733 	 * Theoretically we came here from a queue entry that was added
734 	 * Just before the queue was closed, so it should be empty anyway.
735 	 * Also removes us from worklist if needed.
736 	 */
737 	ng_flush_input_queue(node);
738 
739 	/* Ask the type if it has anything to do in this case */
740 	if (node->nd_type && node->nd_type->shutdown) {
741 		(*node->nd_type->shutdown)(node);
742 		if (NG_NODE_IS_VALID(node)) {
743 			/*
744 			 * Well, blow me down if the node code hasn't declared
745 			 * that it doesn't want to die.
746 			 * Presumably it is a persistant node.
747 			 * If we REALLY want it to go away,
748 			 *  e.g. hardware going away,
749 			 * Our caller should set NGF_REALLY_DIE in nd_flags.
750 			 */
751 			node->nd_flags &= ~(NGF_INVALID|NGF_CLOSING);
752 			NG_NODE_UNREF(node); /* Assume they still have theirs */
753 			return;
754 		}
755 	} else {				/* do the default thing */
756 		NG_NODE_UNREF(node);
757 	}
758 
759 	ng_unname(node); /* basically a NOP these days */
760 
761 	/*
762 	 * Remove extra reference, possibly the last
763 	 * Possible other holders of references may include
764 	 * timeout callouts, but theoretically the node's supposed to
765 	 * have cancelled them. Possibly hardware dependencies may
766 	 * force a driver to 'linger' with a reference.
767 	 */
768 	NG_NODE_UNREF(node);
769 }
770 
771 /*
772  * Remove a reference to the node, possibly the last.
773  * deadnode always acts as it it were the last.
774  */
775 int
776 ng_unref_node(node_p node)
777 {
778 	int v;
779 
780 	if (node == &ng_deadnode) {
781 		return (0);
782 	}
783 
784 	v = atomic_fetchadd_int(&node->nd_refs, -1);
785 
786 	if (v == 1) { /* we were the last */
787 
788 		mtx_lock(&ng_namehash_mtx);
789 		node->nd_type->refs--; /* XXX maybe should get types lock? */
790 		LIST_REMOVE(node, nd_nodes);
791 		mtx_unlock(&ng_namehash_mtx);
792 
793 		mtx_lock(&ng_idhash_mtx);
794 		LIST_REMOVE(node, nd_idnodes);
795 		mtx_unlock(&ng_idhash_mtx);
796 
797 		mtx_destroy(&node->nd_input_queue.q_mtx);
798 		NG_FREE_NODE(node);
799 	}
800 	return (v - 1);
801 }
802 
803 /************************************************************************
804 			Node ID handling
805 ************************************************************************/
806 static node_p
807 ng_ID2noderef(ng_ID_t ID)
808 {
809 	node_p node;
810 	mtx_lock(&ng_idhash_mtx);
811 	NG_IDHASH_FIND(ID, node);
812 	if(node)
813 		NG_NODE_REF(node);
814 	mtx_unlock(&ng_idhash_mtx);
815 	return(node);
816 }
817 
818 ng_ID_t
819 ng_node2ID(node_p node)
820 {
821 	return (node ? NG_NODE_ID(node) : 0);
822 }
823 
824 /************************************************************************
825 			Node name handling
826 ************************************************************************/
827 
828 /*
829  * Assign a node a name. Once assigned, the name cannot be changed.
830  */
831 int
832 ng_name_node(node_p node, const char *name)
833 {
834 	int i, hash;
835 	node_p node2;
836 
837 	/* Check the name is valid */
838 	for (i = 0; i < NG_NODESIZ; i++) {
839 		if (name[i] == '\0' || name[i] == '.' || name[i] == ':')
840 			break;
841 	}
842 	if (i == 0 || name[i] != '\0') {
843 		TRAP_ERROR();
844 		return (EINVAL);
845 	}
846 	if (ng_decodeidname(name) != 0) { /* valid IDs not allowed here */
847 		TRAP_ERROR();
848 		return (EINVAL);
849 	}
850 
851 	/* Check the name isn't already being used */
852 	if ((node2 = ng_name2noderef(node, name)) != NULL) {
853 		NG_NODE_UNREF(node2);
854 		TRAP_ERROR();
855 		return (EADDRINUSE);
856 	}
857 
858 	/* copy it */
859 	strlcpy(NG_NODE_NAME(node), name, NG_NODESIZ);
860 
861 	/* Update name hash. */
862 	NG_NAMEHASH(name, hash);
863 	mtx_lock(&ng_namehash_mtx);
864 	LIST_REMOVE(node, nd_nodes);
865 	LIST_INSERT_HEAD(&V_ng_name_hash[hash], node, nd_nodes);
866 	mtx_unlock(&ng_namehash_mtx);
867 
868 	return (0);
869 }
870 
871 /*
872  * Find a node by absolute name. The name should NOT end with ':'
873  * The name "." means "this node" and "[xxx]" means "the node
874  * with ID (ie, at address) xxx".
875  *
876  * Returns the node if found, else NULL.
877  * Eventually should add something faster than a sequential search.
878  * Note it acquires a reference on the node so you can be sure it's still
879  * there.
880  */
881 node_p
882 ng_name2noderef(node_p here, const char *name)
883 {
884 	node_p node;
885 	ng_ID_t temp;
886 	int	hash;
887 
888 	/* "." means "this node" */
889 	if (strcmp(name, ".") == 0) {
890 		NG_NODE_REF(here);
891 		return(here);
892 	}
893 
894 	/* Check for name-by-ID */
895 	if ((temp = ng_decodeidname(name)) != 0) {
896 		return (ng_ID2noderef(temp));
897 	}
898 
899 	/* Find node by name */
900 	NG_NAMEHASH(name, hash);
901 	mtx_lock(&ng_namehash_mtx);
902 	LIST_FOREACH(node, &V_ng_name_hash[hash], nd_nodes) {
903 		if (NG_NODE_IS_VALID(node) &&
904 		    (strcmp(NG_NODE_NAME(node), name) == 0)) {
905 			break;
906 		}
907 	}
908 	if (node)
909 		NG_NODE_REF(node);
910 	mtx_unlock(&ng_namehash_mtx);
911 	return (node);
912 }
913 
914 /*
915  * Decode an ID name, eg. "[f03034de]". Returns 0 if the
916  * string is not valid, otherwise returns the value.
917  */
918 static ng_ID_t
919 ng_decodeidname(const char *name)
920 {
921 	const int len = strlen(name);
922 	char *eptr;
923 	u_long val;
924 
925 	/* Check for proper length, brackets, no leading junk */
926 	if ((len < 3)
927 	|| (name[0] != '[')
928 	|| (name[len - 1] != ']')
929 	|| (!isxdigit(name[1]))) {
930 		return ((ng_ID_t)0);
931 	}
932 
933 	/* Decode number */
934 	val = strtoul(name + 1, &eptr, 16);
935 	if ((eptr - name != len - 1)
936 	|| (val == ULONG_MAX)
937 	|| (val == 0)) {
938 		return ((ng_ID_t)0);
939 	}
940 	return (ng_ID_t)val;
941 }
942 
943 /*
944  * Remove a name from a node. This should only be called
945  * when shutting down and removing the node.
946  * IF we allow name changing this may be more resurrected.
947  */
948 void
949 ng_unname(node_p node)
950 {
951 }
952 
953 /************************************************************************
954 			Hook routines
955  Names are not optional. Hooks are always connected, except for a
956  brief moment within these routines. On invalidation or during creation
957  they are connected to the 'dead' hook.
958 ************************************************************************/
959 
960 /*
961  * Remove a hook reference
962  */
963 void
964 ng_unref_hook(hook_p hook)
965 {
966 	int v;
967 
968 	if (hook == &ng_deadhook) {
969 		return;
970 	}
971 
972 	v = atomic_fetchadd_int(&hook->hk_refs, -1);
973 
974 	if (v == 1) { /* we were the last */
975 		if (_NG_HOOK_NODE(hook)) /* it'll probably be ng_deadnode */
976 			_NG_NODE_UNREF((_NG_HOOK_NODE(hook)));
977 		NG_FREE_HOOK(hook);
978 	}
979 }
980 
981 /*
982  * Add an unconnected hook to a node. Only used internally.
983  * Assumes node is locked. (XXX not yet true )
984  */
985 static int
986 ng_add_hook(node_p node, const char *name, hook_p *hookp)
987 {
988 	hook_p hook;
989 	int error = 0;
990 
991 	/* Check that the given name is good */
992 	if (name == NULL) {
993 		TRAP_ERROR();
994 		return (EINVAL);
995 	}
996 	if (ng_findhook(node, name) != NULL) {
997 		TRAP_ERROR();
998 		return (EEXIST);
999 	}
1000 
1001 	/* Allocate the hook and link it up */
1002 	NG_ALLOC_HOOK(hook);
1003 	if (hook == NULL) {
1004 		TRAP_ERROR();
1005 		return (ENOMEM);
1006 	}
1007 	hook->hk_refs = 1;		/* add a reference for us to return */
1008 	hook->hk_flags = HK_INVALID;
1009 	hook->hk_peer = &ng_deadhook;	/* start off this way */
1010 	hook->hk_node = node;
1011 	NG_NODE_REF(node);		/* each hook counts as a reference */
1012 
1013 	/* Set hook name */
1014 	strlcpy(NG_HOOK_NAME(hook), name, NG_HOOKSIZ);
1015 
1016 	/*
1017 	 * Check if the node type code has something to say about it
1018 	 * If it fails, the unref of the hook will also unref the node.
1019 	 */
1020 	if (node->nd_type->newhook != NULL) {
1021 		if ((error = (*node->nd_type->newhook)(node, hook, name))) {
1022 			NG_HOOK_UNREF(hook);	/* this frees the hook */
1023 			return (error);
1024 		}
1025 	}
1026 	/*
1027 	 * The 'type' agrees so far, so go ahead and link it in.
1028 	 * We'll ask again later when we actually connect the hooks.
1029 	 */
1030 	LIST_INSERT_HEAD(&node->nd_hooks, hook, hk_hooks);
1031 	node->nd_numhooks++;
1032 	NG_HOOK_REF(hook);	/* one for the node */
1033 
1034 	if (hookp)
1035 		*hookp = hook;
1036 	return (0);
1037 }
1038 
1039 /*
1040  * Find a hook
1041  *
1042  * Node types may supply their own optimized routines for finding
1043  * hooks.  If none is supplied, we just do a linear search.
1044  * XXX Possibly we should add a reference to the hook?
1045  */
1046 hook_p
1047 ng_findhook(node_p node, const char *name)
1048 {
1049 	hook_p hook;
1050 
1051 	if (node->nd_type->findhook != NULL)
1052 		return (*node->nd_type->findhook)(node, name);
1053 	LIST_FOREACH(hook, &node->nd_hooks, hk_hooks) {
1054 		if (NG_HOOK_IS_VALID(hook)
1055 		&& (strcmp(NG_HOOK_NAME(hook), name) == 0))
1056 			return (hook);
1057 	}
1058 	return (NULL);
1059 }
1060 
1061 /*
1062  * Destroy a hook
1063  *
1064  * As hooks are always attached, this really destroys two hooks.
1065  * The one given, and the one attached to it. Disconnect the hooks
1066  * from each other first. We reconnect the peer hook to the 'dead'
1067  * hook so that it can still exist after we depart. We then
1068  * send the peer its own destroy message. This ensures that we only
1069  * interact with the peer's structures when it is locked processing that
1070  * message. We hold a reference to the peer hook so we are guaranteed that
1071  * the peer hook and node are still going to exist until
1072  * we are finished there as the hook holds a ref on the node.
1073  * We run this same code again on the peer hook, but that time it is already
1074  * attached to the 'dead' hook.
1075  *
1076  * This routine is called at all stages of hook creation
1077  * on error detection and must be able to handle any such stage.
1078  */
1079 void
1080 ng_destroy_hook(hook_p hook)
1081 {
1082 	hook_p peer;
1083 	node_p node;
1084 
1085 	if (hook == &ng_deadhook) {	/* better safe than sorry */
1086 		printf("ng_destroy_hook called on deadhook\n");
1087 		return;
1088 	}
1089 
1090 	/*
1091 	 * Protect divorce process with mutex, to avoid races on
1092 	 * simultaneous disconnect.
1093 	 */
1094 	mtx_lock(&ng_topo_mtx);
1095 
1096 	hook->hk_flags |= HK_INVALID;
1097 
1098 	peer = NG_HOOK_PEER(hook);
1099 	node = NG_HOOK_NODE(hook);
1100 
1101 	if (peer && (peer != &ng_deadhook)) {
1102 		/*
1103 		 * Set the peer to point to ng_deadhook
1104 		 * from this moment on we are effectively independent it.
1105 		 * send it an rmhook message of it's own.
1106 		 */
1107 		peer->hk_peer = &ng_deadhook;	/* They no longer know us */
1108 		hook->hk_peer = &ng_deadhook;	/* Nor us, them */
1109 		if (NG_HOOK_NODE(peer) == &ng_deadnode) {
1110 			/*
1111 			 * If it's already divorced from a node,
1112 			 * just free it.
1113 			 */
1114 			mtx_unlock(&ng_topo_mtx);
1115 		} else {
1116 			mtx_unlock(&ng_topo_mtx);
1117 			ng_rmhook_self(peer); 	/* Send it a surprise */
1118 		}
1119 		NG_HOOK_UNREF(peer);		/* account for peer link */
1120 		NG_HOOK_UNREF(hook);		/* account for peer link */
1121 	} else
1122 		mtx_unlock(&ng_topo_mtx);
1123 
1124 	mtx_assert(&ng_topo_mtx, MA_NOTOWNED);
1125 
1126 	/*
1127 	 * Remove the hook from the node's list to avoid possible recursion
1128 	 * in case the disconnection results in node shutdown.
1129 	 */
1130 	if (node == &ng_deadnode) { /* happens if called from ng_con_nodes() */
1131 		return;
1132 	}
1133 	LIST_REMOVE(hook, hk_hooks);
1134 	node->nd_numhooks--;
1135 	if (node->nd_type->disconnect) {
1136 		/*
1137 		 * The type handler may elect to destroy the node so don't
1138 		 * trust its existence after this point. (except
1139 		 * that we still hold a reference on it. (which we
1140 		 * inherrited from the hook we are destroying)
1141 		 */
1142 		(*node->nd_type->disconnect) (hook);
1143 	}
1144 
1145 	/*
1146 	 * Note that because we will point to ng_deadnode, the original node
1147 	 * is not decremented automatically so we do that manually.
1148 	 */
1149 	_NG_HOOK_NODE(hook) = &ng_deadnode;
1150 	NG_NODE_UNREF(node);	/* We no longer point to it so adjust count */
1151 	NG_HOOK_UNREF(hook);	/* Account for linkage (in list) to node */
1152 }
1153 
1154 /*
1155  * Take two hooks on a node and merge the connection so that the given node
1156  * is effectively bypassed.
1157  */
1158 int
1159 ng_bypass(hook_p hook1, hook_p hook2)
1160 {
1161 	if (hook1->hk_node != hook2->hk_node) {
1162 		TRAP_ERROR();
1163 		return (EINVAL);
1164 	}
1165 	hook1->hk_peer->hk_peer = hook2->hk_peer;
1166 	hook2->hk_peer->hk_peer = hook1->hk_peer;
1167 
1168 	hook1->hk_peer = &ng_deadhook;
1169 	hook2->hk_peer = &ng_deadhook;
1170 
1171 	NG_HOOK_UNREF(hook1);
1172 	NG_HOOK_UNREF(hook2);
1173 
1174 	/* XXX If we ever cache methods on hooks update them as well */
1175 	ng_destroy_hook(hook1);
1176 	ng_destroy_hook(hook2);
1177 	return (0);
1178 }
1179 
1180 /*
1181  * Install a new netgraph type
1182  */
1183 int
1184 ng_newtype(struct ng_type *tp)
1185 {
1186 	const size_t namelen = strlen(tp->name);
1187 
1188 	/* Check version and type name fields */
1189 	if ((tp->version != NG_ABI_VERSION)
1190 	|| (namelen == 0)
1191 	|| (namelen >= NG_TYPESIZ)) {
1192 		TRAP_ERROR();
1193 		if (tp->version != NG_ABI_VERSION) {
1194 			printf("Netgraph: Node type rejected. ABI mismatch. Suggest recompile\n");
1195 		}
1196 		return (EINVAL);
1197 	}
1198 
1199 	/* Check for name collision */
1200 	if (ng_findtype(tp->name) != NULL) {
1201 		TRAP_ERROR();
1202 		return (EEXIST);
1203 	}
1204 
1205 
1206 	/* Link in new type */
1207 	mtx_lock(&ng_typelist_mtx);
1208 	LIST_INSERT_HEAD(&ng_typelist, tp, types);
1209 	tp->refs = 1;	/* first ref is linked list */
1210 	mtx_unlock(&ng_typelist_mtx);
1211 	return (0);
1212 }
1213 
1214 /*
1215  * unlink a netgraph type
1216  * If no examples exist
1217  */
1218 int
1219 ng_rmtype(struct ng_type *tp)
1220 {
1221 	/* Check for name collision */
1222 	if (tp->refs != 1) {
1223 		TRAP_ERROR();
1224 		return (EBUSY);
1225 	}
1226 
1227 	/* Unlink type */
1228 	mtx_lock(&ng_typelist_mtx);
1229 	LIST_REMOVE(tp, types);
1230 	mtx_unlock(&ng_typelist_mtx);
1231 	return (0);
1232 }
1233 
1234 /*
1235  * Look for a type of the name given
1236  */
1237 struct ng_type *
1238 ng_findtype(const char *typename)
1239 {
1240 	struct ng_type *type;
1241 
1242 	mtx_lock(&ng_typelist_mtx);
1243 	LIST_FOREACH(type, &ng_typelist, types) {
1244 		if (strcmp(type->name, typename) == 0)
1245 			break;
1246 	}
1247 	mtx_unlock(&ng_typelist_mtx);
1248 	return (type);
1249 }
1250 
1251 /************************************************************************
1252 			Composite routines
1253 ************************************************************************/
1254 /*
1255  * Connect two nodes using the specified hooks, using queued functions.
1256  */
1257 static int
1258 ng_con_part3(node_p node, item_p item, hook_p hook)
1259 {
1260 	int	error = 0;
1261 
1262 	/*
1263 	 * When we run, we know that the node 'node' is locked for us.
1264 	 * Our caller has a reference on the hook.
1265 	 * Our caller has a reference on the node.
1266 	 * (In this case our caller is ng_apply_item() ).
1267 	 * The peer hook has a reference on the hook.
1268 	 * We are all set up except for the final call to the node, and
1269 	 * the clearing of the INVALID flag.
1270 	 */
1271 	if (NG_HOOK_NODE(hook) == &ng_deadnode) {
1272 		/*
1273 		 * The node must have been freed again since we last visited
1274 		 * here. ng_destry_hook() has this effect but nothing else does.
1275 		 * We should just release our references and
1276 		 * free anything we can think of.
1277 		 * Since we know it's been destroyed, and it's our caller
1278 		 * that holds the references, just return.
1279 		 */
1280 		ERROUT(ENOENT);
1281 	}
1282 	if (hook->hk_node->nd_type->connect) {
1283 		if ((error = (*hook->hk_node->nd_type->connect) (hook))) {
1284 			ng_destroy_hook(hook);	/* also zaps peer */
1285 			printf("failed in ng_con_part3()\n");
1286 			ERROUT(error);
1287 		}
1288 	}
1289 	/*
1290 	 *  XXX this is wrong for SMP. Possibly we need
1291 	 * to separate out 'create' and 'invalid' flags.
1292 	 * should only set flags on hooks we have locked under our node.
1293 	 */
1294 	hook->hk_flags &= ~HK_INVALID;
1295 done:
1296 	NG_FREE_ITEM(item);
1297 	return (error);
1298 }
1299 
1300 static int
1301 ng_con_part2(node_p node, item_p item, hook_p hook)
1302 {
1303 	hook_p	peer;
1304 	int	error = 0;
1305 
1306 	/*
1307 	 * When we run, we know that the node 'node' is locked for us.
1308 	 * Our caller has a reference on the hook.
1309 	 * Our caller has a reference on the node.
1310 	 * (In this case our caller is ng_apply_item() ).
1311 	 * The peer hook has a reference on the hook.
1312 	 * our node pointer points to the 'dead' node.
1313 	 * First check the hook name is unique.
1314 	 * Should not happen because we checked before queueing this.
1315 	 */
1316 	if (ng_findhook(node, NG_HOOK_NAME(hook)) != NULL) {
1317 		TRAP_ERROR();
1318 		ng_destroy_hook(hook); /* should destroy peer too */
1319 		printf("failed in ng_con_part2()\n");
1320 		ERROUT(EEXIST);
1321 	}
1322 	/*
1323 	 * Check if the node type code has something to say about it
1324 	 * If it fails, the unref of the hook will also unref the attached node,
1325 	 * however since that node is 'ng_deadnode' this will do nothing.
1326 	 * The peer hook will also be destroyed.
1327 	 */
1328 	if (node->nd_type->newhook != NULL) {
1329 		if ((error = (*node->nd_type->newhook)(node, hook,
1330 		    hook->hk_name))) {
1331 			ng_destroy_hook(hook); /* should destroy peer too */
1332 			printf("failed in ng_con_part2()\n");
1333 			ERROUT(error);
1334 		}
1335 	}
1336 
1337 	/*
1338 	 * The 'type' agrees so far, so go ahead and link it in.
1339 	 * We'll ask again later when we actually connect the hooks.
1340 	 */
1341 	hook->hk_node = node;		/* just overwrite ng_deadnode */
1342 	NG_NODE_REF(node);		/* each hook counts as a reference */
1343 	LIST_INSERT_HEAD(&node->nd_hooks, hook, hk_hooks);
1344 	node->nd_numhooks++;
1345 	NG_HOOK_REF(hook);	/* one for the node */
1346 
1347 	/*
1348 	 * We now have a symmetrical situation, where both hooks have been
1349 	 * linked to their nodes, the newhook methods have been called
1350 	 * And the references are all correct. The hooks are still marked
1351 	 * as invalid, as we have not called the 'connect' methods
1352 	 * yet.
1353 	 * We can call the local one immediately as we have the
1354 	 * node locked, but we need to queue the remote one.
1355 	 */
1356 	if (hook->hk_node->nd_type->connect) {
1357 		if ((error = (*hook->hk_node->nd_type->connect) (hook))) {
1358 			ng_destroy_hook(hook);	/* also zaps peer */
1359 			printf("failed in ng_con_part2(A)\n");
1360 			ERROUT(error);
1361 		}
1362 	}
1363 
1364 	/*
1365 	 * Acquire topo mutex to avoid race with ng_destroy_hook().
1366 	 */
1367 	mtx_lock(&ng_topo_mtx);
1368 	peer = hook->hk_peer;
1369 	if (peer == &ng_deadhook) {
1370 		mtx_unlock(&ng_topo_mtx);
1371 		printf("failed in ng_con_part2(B)\n");
1372 		ng_destroy_hook(hook);
1373 		ERROUT(ENOENT);
1374 	}
1375 	mtx_unlock(&ng_topo_mtx);
1376 
1377 	if ((error = ng_send_fn2(peer->hk_node, peer, item, &ng_con_part3,
1378 	    NULL, 0, NG_REUSE_ITEM))) {
1379 		printf("failed in ng_con_part2(C)\n");
1380 		ng_destroy_hook(hook);	/* also zaps peer */
1381 		return (error);		/* item was consumed. */
1382 	}
1383 	hook->hk_flags &= ~HK_INVALID; /* need both to be able to work */
1384 	return (0);			/* item was consumed. */
1385 done:
1386 	NG_FREE_ITEM(item);
1387 	return (error);
1388 }
1389 
1390 /*
1391  * Connect this node with another node. We assume that this node is
1392  * currently locked, as we are only called from an NGM_CONNECT message.
1393  */
1394 static int
1395 ng_con_nodes(item_p item, node_p node, const char *name,
1396     node_p node2, const char *name2)
1397 {
1398 	int	error;
1399 	hook_p	hook;
1400 	hook_p	hook2;
1401 
1402 	if (ng_findhook(node2, name2) != NULL) {
1403 		return(EEXIST);
1404 	}
1405 	if ((error = ng_add_hook(node, name, &hook)))  /* gives us a ref */
1406 		return (error);
1407 	/* Allocate the other hook and link it up */
1408 	NG_ALLOC_HOOK(hook2);
1409 	if (hook2 == NULL) {
1410 		TRAP_ERROR();
1411 		ng_destroy_hook(hook);	/* XXX check ref counts so far */
1412 		NG_HOOK_UNREF(hook);	/* including our ref */
1413 		return (ENOMEM);
1414 	}
1415 	hook2->hk_refs = 1;		/* start with a reference for us. */
1416 	hook2->hk_flags = HK_INVALID;
1417 	hook2->hk_peer = hook;		/* Link the two together */
1418 	hook->hk_peer = hook2;
1419 	NG_HOOK_REF(hook);		/* Add a ref for the peer to each*/
1420 	NG_HOOK_REF(hook2);
1421 	hook2->hk_node = &ng_deadnode;
1422 	strlcpy(NG_HOOK_NAME(hook2), name2, NG_HOOKSIZ);
1423 
1424 	/*
1425 	 * Queue the function above.
1426 	 * Procesing continues in that function in the lock context of
1427 	 * the other node.
1428 	 */
1429 	if ((error = ng_send_fn2(node2, hook2, item, &ng_con_part2, NULL, 0,
1430 	    NG_NOFLAGS))) {
1431 		printf("failed in ng_con_nodes(): %d\n", error);
1432 		ng_destroy_hook(hook);	/* also zaps peer */
1433 	}
1434 
1435 	NG_HOOK_UNREF(hook);		/* Let each hook go if it wants to */
1436 	NG_HOOK_UNREF(hook2);
1437 	return (error);
1438 }
1439 
1440 /*
1441  * Make a peer and connect.
1442  * We assume that the local node is locked.
1443  * The new node probably doesn't need a lock until
1444  * it has a hook, because it cannot really have any work until then,
1445  * but we should think about it a bit more.
1446  *
1447  * The problem may come if the other node also fires up
1448  * some hardware or a timer or some other source of activation,
1449  * also it may already get a command msg via it's ID.
1450  *
1451  * We could use the same method as ng_con_nodes() but we'd have
1452  * to add ability to remove the node when failing. (Not hard, just
1453  * make arg1 point to the node to remove).
1454  * Unless of course we just ignore failure to connect and leave
1455  * an unconnected node?
1456  */
1457 static int
1458 ng_mkpeer(node_p node, const char *name, const char *name2, char *type)
1459 {
1460 	node_p	node2;
1461 	hook_p	hook1, hook2;
1462 	int	error;
1463 
1464 	if ((error = ng_make_node(type, &node2))) {
1465 		return (error);
1466 	}
1467 
1468 	if ((error = ng_add_hook(node, name, &hook1))) { /* gives us a ref */
1469 		ng_rmnode(node2, NULL, NULL, 0);
1470 		return (error);
1471 	}
1472 
1473 	if ((error = ng_add_hook(node2, name2, &hook2))) {
1474 		ng_rmnode(node2, NULL, NULL, 0);
1475 		ng_destroy_hook(hook1);
1476 		NG_HOOK_UNREF(hook1);
1477 		return (error);
1478 	}
1479 
1480 	/*
1481 	 * Actually link the two hooks together.
1482 	 */
1483 	hook1->hk_peer = hook2;
1484 	hook2->hk_peer = hook1;
1485 
1486 	/* Each hook is referenced by the other */
1487 	NG_HOOK_REF(hook1);
1488 	NG_HOOK_REF(hook2);
1489 
1490 	/* Give each node the opportunity to veto the pending connection */
1491 	if (hook1->hk_node->nd_type->connect) {
1492 		error = (*hook1->hk_node->nd_type->connect) (hook1);
1493 	}
1494 
1495 	if ((error == 0) && hook2->hk_node->nd_type->connect) {
1496 		error = (*hook2->hk_node->nd_type->connect) (hook2);
1497 
1498 	}
1499 
1500 	/*
1501 	 * drop the references we were holding on the two hooks.
1502 	 */
1503 	if (error) {
1504 		ng_destroy_hook(hook2);	/* also zaps hook1 */
1505 		ng_rmnode(node2, NULL, NULL, 0);
1506 	} else {
1507 		/* As a last act, allow the hooks to be used */
1508 		hook1->hk_flags &= ~HK_INVALID;
1509 		hook2->hk_flags &= ~HK_INVALID;
1510 	}
1511 	NG_HOOK_UNREF(hook1);
1512 	NG_HOOK_UNREF(hook2);
1513 	return (error);
1514 }
1515 
1516 /************************************************************************
1517 		Utility routines to send self messages
1518 ************************************************************************/
1519 
1520 /* Shut this node down as soon as everyone is clear of it */
1521 /* Should add arg "immediately" to jump the queue */
1522 int
1523 ng_rmnode_self(node_p node)
1524 {
1525 	int		error;
1526 
1527 	if (node == &ng_deadnode)
1528 		return (0);
1529 	node->nd_flags |= NGF_INVALID;
1530 	if (node->nd_flags & NGF_CLOSING)
1531 		return (0);
1532 
1533 	error = ng_send_fn(node, NULL, &ng_rmnode, NULL, 0);
1534 	return (error);
1535 }
1536 
1537 static void
1538 ng_rmhook_part2(node_p node, hook_p hook, void *arg1, int arg2)
1539 {
1540 	ng_destroy_hook(hook);
1541 	return ;
1542 }
1543 
1544 int
1545 ng_rmhook_self(hook_p hook)
1546 {
1547 	int		error;
1548 	node_p node = NG_HOOK_NODE(hook);
1549 
1550 	if (node == &ng_deadnode)
1551 		return (0);
1552 
1553 	error = ng_send_fn(node, hook, &ng_rmhook_part2, NULL, 0);
1554 	return (error);
1555 }
1556 
1557 /***********************************************************************
1558  * Parse and verify a string of the form:  <NODE:><PATH>
1559  *
1560  * Such a string can refer to a specific node or a specific hook
1561  * on a specific node, depending on how you look at it. In the
1562  * latter case, the PATH component must not end in a dot.
1563  *
1564  * Both <NODE:> and <PATH> are optional. The <PATH> is a string
1565  * of hook names separated by dots. This breaks out the original
1566  * string, setting *nodep to "NODE" (or NULL if none) and *pathp
1567  * to "PATH" (or NULL if degenerate). Also, *hookp will point to
1568  * the final hook component of <PATH>, if any, otherwise NULL.
1569  *
1570  * This returns -1 if the path is malformed. The char ** are optional.
1571  ***********************************************************************/
1572 int
1573 ng_path_parse(char *addr, char **nodep, char **pathp, char **hookp)
1574 {
1575 	char	*node, *path, *hook;
1576 	int	k;
1577 
1578 	/*
1579 	 * Extract absolute NODE, if any
1580 	 */
1581 	for (path = addr; *path && *path != ':'; path++);
1582 	if (*path) {
1583 		node = addr;	/* Here's the NODE */
1584 		*path++ = '\0';	/* Here's the PATH */
1585 
1586 		/* Node name must not be empty */
1587 		if (!*node)
1588 			return -1;
1589 
1590 		/* A name of "." is OK; otherwise '.' not allowed */
1591 		if (strcmp(node, ".") != 0) {
1592 			for (k = 0; node[k]; k++)
1593 				if (node[k] == '.')
1594 					return -1;
1595 		}
1596 	} else {
1597 		node = NULL;	/* No absolute NODE */
1598 		path = addr;	/* Here's the PATH */
1599 	}
1600 
1601 	/* Snoop for illegal characters in PATH */
1602 	for (k = 0; path[k]; k++)
1603 		if (path[k] == ':')
1604 			return -1;
1605 
1606 	/* Check for no repeated dots in PATH */
1607 	for (k = 0; path[k]; k++)
1608 		if (path[k] == '.' && path[k + 1] == '.')
1609 			return -1;
1610 
1611 	/* Remove extra (degenerate) dots from beginning or end of PATH */
1612 	if (path[0] == '.')
1613 		path++;
1614 	if (*path && path[strlen(path) - 1] == '.')
1615 		path[strlen(path) - 1] = 0;
1616 
1617 	/* If PATH has a dot, then we're not talking about a hook */
1618 	if (*path) {
1619 		for (hook = path, k = 0; path[k]; k++)
1620 			if (path[k] == '.') {
1621 				hook = NULL;
1622 				break;
1623 			}
1624 	} else
1625 		path = hook = NULL;
1626 
1627 	/* Done */
1628 	if (nodep)
1629 		*nodep = node;
1630 	if (pathp)
1631 		*pathp = path;
1632 	if (hookp)
1633 		*hookp = hook;
1634 	return (0);
1635 }
1636 
1637 /*
1638  * Given a path, which may be absolute or relative, and a starting node,
1639  * return the destination node.
1640  */
1641 int
1642 ng_path2noderef(node_p here, const char *address,
1643 				node_p *destp, hook_p *lasthook)
1644 {
1645 	char    fullpath[NG_PATHSIZ];
1646 	char   *nodename, *path, pbuf[2];
1647 	node_p  node, oldnode;
1648 	char   *cp;
1649 	hook_p hook = NULL;
1650 
1651 	/* Initialize */
1652 	if (destp == NULL) {
1653 		TRAP_ERROR();
1654 		return EINVAL;
1655 	}
1656 	*destp = NULL;
1657 
1658 	/* Make a writable copy of address for ng_path_parse() */
1659 	strncpy(fullpath, address, sizeof(fullpath) - 1);
1660 	fullpath[sizeof(fullpath) - 1] = '\0';
1661 
1662 	/* Parse out node and sequence of hooks */
1663 	if (ng_path_parse(fullpath, &nodename, &path, NULL) < 0) {
1664 		TRAP_ERROR();
1665 		return EINVAL;
1666 	}
1667 	if (path == NULL) {
1668 		pbuf[0] = '.';	/* Needs to be writable */
1669 		pbuf[1] = '\0';
1670 		path = pbuf;
1671 	}
1672 
1673 	/*
1674 	 * For an absolute address, jump to the starting node.
1675 	 * Note that this holds a reference on the node for us.
1676 	 * Don't forget to drop the reference if we don't need it.
1677 	 */
1678 	if (nodename) {
1679 		node = ng_name2noderef(here, nodename);
1680 		if (node == NULL) {
1681 			TRAP_ERROR();
1682 			return (ENOENT);
1683 		}
1684 	} else {
1685 		if (here == NULL) {
1686 			TRAP_ERROR();
1687 			return (EINVAL);
1688 		}
1689 		node = here;
1690 		NG_NODE_REF(node);
1691 	}
1692 
1693 	/*
1694 	 * Now follow the sequence of hooks
1695 	 * XXX
1696 	 * We actually cannot guarantee that the sequence
1697 	 * is not being demolished as we crawl along it
1698 	 * without extra-ordinary locking etc.
1699 	 * So this is a bit dodgy to say the least.
1700 	 * We can probably hold up some things by holding
1701 	 * the nodelist mutex for the time of this
1702 	 * crawl if we wanted.. At least that way we wouldn't have to
1703 	 * worry about the nodes disappearing, but the hooks would still
1704 	 * be a problem.
1705 	 */
1706 	for (cp = path; node != NULL && *cp != '\0'; ) {
1707 		char *segment;
1708 
1709 		/*
1710 		 * Break out the next path segment. Replace the dot we just
1711 		 * found with a NUL; "cp" points to the next segment (or the
1712 		 * NUL at the end).
1713 		 */
1714 		for (segment = cp; *cp != '\0'; cp++) {
1715 			if (*cp == '.') {
1716 				*cp++ = '\0';
1717 				break;
1718 			}
1719 		}
1720 
1721 		/* Empty segment */
1722 		if (*segment == '\0')
1723 			continue;
1724 
1725 		/* We have a segment, so look for a hook by that name */
1726 		hook = ng_findhook(node, segment);
1727 
1728 		/* Can't get there from here... */
1729 		if (hook == NULL
1730 		    || NG_HOOK_PEER(hook) == NULL
1731 		    || NG_HOOK_NOT_VALID(hook)
1732 		    || NG_HOOK_NOT_VALID(NG_HOOK_PEER(hook))) {
1733 			TRAP_ERROR();
1734 			NG_NODE_UNREF(node);
1735 #if 0
1736 			printf("hooknotvalid %s %s %d %d %d %d ",
1737 					path,
1738 					segment,
1739 					hook == NULL,
1740 					NG_HOOK_PEER(hook) == NULL,
1741 					NG_HOOK_NOT_VALID(hook),
1742 					NG_HOOK_NOT_VALID(NG_HOOK_PEER(hook)));
1743 #endif
1744 			return (ENOENT);
1745 		}
1746 
1747 		/*
1748 		 * Hop on over to the next node
1749 		 * XXX
1750 		 * Big race conditions here as hooks and nodes go away
1751 		 * *** Idea.. store an ng_ID_t in each hook and use that
1752 		 * instead of the direct hook in this crawl?
1753 		 */
1754 		oldnode = node;
1755 		if ((node = NG_PEER_NODE(hook)))
1756 			NG_NODE_REF(node);	/* XXX RACE */
1757 		NG_NODE_UNREF(oldnode);	/* XXX another race */
1758 		if (NG_NODE_NOT_VALID(node)) {
1759 			NG_NODE_UNREF(node);	/* XXX more races */
1760 			node = NULL;
1761 		}
1762 	}
1763 
1764 	/* If node somehow missing, fail here (probably this is not needed) */
1765 	if (node == NULL) {
1766 		TRAP_ERROR();
1767 		return (ENXIO);
1768 	}
1769 
1770 	/* Done */
1771 	*destp = node;
1772 	if (lasthook != NULL)
1773 		*lasthook = (hook ? NG_HOOK_PEER(hook) : NULL);
1774 	return (0);
1775 }
1776 
1777 /***************************************************************\
1778 * Input queue handling.
1779 * All activities are submitted to the node via the input queue
1780 * which implements a multiple-reader/single-writer gate.
1781 * Items which cannot be handled immediately are queued.
1782 *
1783 * read-write queue locking inline functions			*
1784 \***************************************************************/
1785 
1786 static __inline void	ng_queue_rw(node_p node, item_p  item, int rw);
1787 static __inline item_p	ng_dequeue(node_p node, int *rw);
1788 static __inline item_p	ng_acquire_read(node_p node, item_p  item);
1789 static __inline item_p	ng_acquire_write(node_p node, item_p  item);
1790 static __inline void	ng_leave_read(node_p node);
1791 static __inline void	ng_leave_write(node_p node);
1792 
1793 /*
1794  * Definition of the bits fields in the ng_queue flag word.
1795  * Defined here rather than in netgraph.h because no-one should fiddle
1796  * with them.
1797  *
1798  * The ordering here may be important! don't shuffle these.
1799  */
1800 /*-
1801  Safety Barrier--------+ (adjustable to suit taste) (not used yet)
1802                        |
1803                        V
1804 +-------+-------+-------+-------+-------+-------+-------+-------+
1805   | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
1806   | |A|c|t|i|v|e| |R|e|a|d|e|r| |C|o|u|n|t| | | | | | | | | |P|A|
1807   | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |O|W|
1808 +-------+-------+-------+-------+-------+-------+-------+-------+
1809   \___________________________ ____________________________/ | |
1810                             V                                | |
1811                   [active reader count]                      | |
1812                                                              | |
1813             Operation Pending -------------------------------+ |
1814                                                                |
1815           Active Writer ---------------------------------------+
1816 
1817 Node queue has such semantics:
1818 - All flags modifications are atomic.
1819 - Reader count can be incremented only if there is no writer or pending flags.
1820   As soon as this can't be done with single operation, it is implemented with
1821   spin loop and atomic_cmpset().
1822 - Writer flag can be set only if there is no any bits set.
1823   It is implemented with atomic_cmpset().
1824 - Pending flag can be set any time, but to avoid collision on queue processing
1825   all queue fields are protected by the mutex.
1826 - Queue processing thread reads queue holding the mutex, but releases it while
1827   processing. When queue is empty pending flag is removed.
1828 */
1829 
1830 #define WRITER_ACTIVE	0x00000001
1831 #define OP_PENDING	0x00000002
1832 #define READER_INCREMENT 0x00000004
1833 #define READER_MASK	0xfffffffc	/* Not valid if WRITER_ACTIVE is set */
1834 #define SAFETY_BARRIER	0x00100000	/* 128K items queued should be enough */
1835 
1836 /* Defines of more elaborate states on the queue */
1837 /* Mask of bits a new read cares about */
1838 #define NGQ_RMASK	(WRITER_ACTIVE|OP_PENDING)
1839 
1840 /* Mask of bits a new write cares about */
1841 #define NGQ_WMASK	(NGQ_RMASK|READER_MASK)
1842 
1843 /* Test to decide if there is something on the queue. */
1844 #define QUEUE_ACTIVE(QP) ((QP)->q_flags & OP_PENDING)
1845 
1846 /* How to decide what the next queued item is. */
1847 #define HEAD_IS_READER(QP)  NGI_QUEUED_READER(STAILQ_FIRST(&(QP)->queue))
1848 #define HEAD_IS_WRITER(QP)  NGI_QUEUED_WRITER(STAILQ_FIRST(&(QP)->queue)) /* notused */
1849 
1850 /* Read the status to decide if the next item on the queue can now run. */
1851 #define QUEUED_READER_CAN_PROCEED(QP)			\
1852 		(((QP)->q_flags & (NGQ_RMASK & ~OP_PENDING)) == 0)
1853 #define QUEUED_WRITER_CAN_PROCEED(QP)			\
1854 		(((QP)->q_flags & (NGQ_WMASK & ~OP_PENDING)) == 0)
1855 
1856 /* Is there a chance of getting ANY work off the queue? */
1857 #define NEXT_QUEUED_ITEM_CAN_PROCEED(QP)				\
1858 	((HEAD_IS_READER(QP)) ? QUEUED_READER_CAN_PROCEED(QP) :		\
1859 				QUEUED_WRITER_CAN_PROCEED(QP))
1860 
1861 #define NGQRW_R 0
1862 #define NGQRW_W 1
1863 
1864 #define NGQ2_WORKQ	0x00000001
1865 
1866 /*
1867  * Taking into account the current state of the queue and node, possibly take
1868  * the next entry off the queue and return it. Return NULL if there was
1869  * nothing we could return, either because there really was nothing there, or
1870  * because the node was in a state where it cannot yet process the next item
1871  * on the queue.
1872  */
1873 static __inline item_p
1874 ng_dequeue(node_p node, int *rw)
1875 {
1876 	item_p item;
1877 	struct ng_queue *ngq = &node->nd_input_queue;
1878 
1879 	/* This MUST be called with the mutex held. */
1880 	mtx_assert(&ngq->q_mtx, MA_OWNED);
1881 
1882 	/* If there is nothing queued, then just return. */
1883 	if (!QUEUE_ACTIVE(ngq)) {
1884 		CTR4(KTR_NET, "%20s: node [%x] (%p) queue empty; "
1885 		    "queue flags 0x%lx", __func__,
1886 		    node->nd_ID, node, ngq->q_flags);
1887 		return (NULL);
1888 	}
1889 
1890 	/*
1891 	 * From here, we can assume there is a head item.
1892 	 * We need to find out what it is and if it can be dequeued, given
1893 	 * the current state of the node.
1894 	 */
1895 	if (HEAD_IS_READER(ngq)) {
1896 		while (1) {
1897 			long t = ngq->q_flags;
1898 			if (t & WRITER_ACTIVE) {
1899 				/* There is writer, reader can't proceed. */
1900 				CTR4(KTR_NET, "%20s: node [%x] (%p) queued reader "
1901 				    "can't proceed; queue flags 0x%lx", __func__,
1902 				    node->nd_ID, node, t);
1903 				return (NULL);
1904 			}
1905 			if (atomic_cmpset_acq_int(&ngq->q_flags, t,
1906 			    t + READER_INCREMENT))
1907 				break;
1908 			cpu_spinwait();
1909 		}
1910 		/* We have got reader lock for the node. */
1911 		*rw = NGQRW_R;
1912 	} else if (atomic_cmpset_acq_int(&ngq->q_flags, OP_PENDING,
1913 	    OP_PENDING + WRITER_ACTIVE)) {
1914 		/* We have got writer lock for the node. */
1915 		*rw = NGQRW_W;
1916 	} else {
1917 		/* There is somebody other, writer can't proceed. */
1918 		CTR4(KTR_NET, "%20s: node [%x] (%p) queued writer "
1919 		    "can't proceed; queue flags 0x%lx", __func__,
1920 		    node->nd_ID, node, ngq->q_flags);
1921 		return (NULL);
1922 	}
1923 
1924 	/*
1925 	 * Now we dequeue the request (whatever it may be) and correct the
1926 	 * pending flags and the next and last pointers.
1927 	 */
1928 	item = STAILQ_FIRST(&ngq->queue);
1929 	STAILQ_REMOVE_HEAD(&ngq->queue, el_next);
1930 	if (STAILQ_EMPTY(&ngq->queue))
1931 		atomic_clear_int(&ngq->q_flags, OP_PENDING);
1932 	CTR6(KTR_NET, "%20s: node [%x] (%p) returning item %p as %s; "
1933 	    "queue flags 0x%lx", __func__,
1934 	    node->nd_ID, node, item, *rw ? "WRITER" : "READER" ,
1935 	    ngq->q_flags);
1936 	return (item);
1937 }
1938 
1939 /*
1940  * Queue a packet to be picked up later by someone else.
1941  * If the queue could be run now, add node to the queue handler's worklist.
1942  */
1943 static __inline void
1944 ng_queue_rw(node_p node, item_p  item, int rw)
1945 {
1946 	struct ng_queue *ngq = &node->nd_input_queue;
1947 	if (rw == NGQRW_W)
1948 		NGI_SET_WRITER(item);
1949 	else
1950 		NGI_SET_READER(item);
1951 
1952 	NG_QUEUE_LOCK(ngq);
1953 	/* Set OP_PENDING flag and enqueue the item. */
1954 	atomic_set_int(&ngq->q_flags, OP_PENDING);
1955 	STAILQ_INSERT_TAIL(&ngq->queue, item, el_next);
1956 
1957 	CTR5(KTR_NET, "%20s: node [%x] (%p) queued item %p as %s", __func__,
1958 	    node->nd_ID, node, item, rw ? "WRITER" : "READER" );
1959 
1960 	/*
1961 	 * We can take the worklist lock with the node locked
1962 	 * BUT NOT THE REVERSE!
1963 	 */
1964 	if (NEXT_QUEUED_ITEM_CAN_PROCEED(ngq))
1965 		ng_worklist_add(node);
1966 	NG_QUEUE_UNLOCK(ngq);
1967 }
1968 
1969 /* Acquire reader lock on node. If node is busy, queue the packet. */
1970 static __inline item_p
1971 ng_acquire_read(node_p node, item_p item)
1972 {
1973 	KASSERT(node != &ng_deadnode,
1974 	    ("%s: working on deadnode", __func__));
1975 
1976 	/* Reader needs node without writer and pending items. */
1977 	while (1) {
1978 		long t = node->nd_input_queue.q_flags;
1979 		if (t & NGQ_RMASK)
1980 			break; /* Node is not ready for reader. */
1981 		if (atomic_cmpset_acq_int(&node->nd_input_queue.q_flags,
1982 		    t, t + READER_INCREMENT)) {
1983 	    		/* Successfully grabbed node */
1984 			CTR4(KTR_NET, "%20s: node [%x] (%p) acquired item %p",
1985 			    __func__, node->nd_ID, node, item);
1986 			return (item);
1987 		}
1988 		cpu_spinwait();
1989 	};
1990 
1991 	/* Queue the request for later. */
1992 	ng_queue_rw(node, item, NGQRW_R);
1993 
1994 	return (NULL);
1995 }
1996 
1997 /* Acquire writer lock on node. If node is busy, queue the packet. */
1998 static __inline item_p
1999 ng_acquire_write(node_p node, item_p item)
2000 {
2001 	KASSERT(node != &ng_deadnode,
2002 	    ("%s: working on deadnode", __func__));
2003 
2004 	/* Writer needs completely idle node. */
2005 	if (atomic_cmpset_acq_int(&node->nd_input_queue.q_flags,
2006 	    0, WRITER_ACTIVE)) {
2007 	    	/* Successfully grabbed node */
2008 		CTR4(KTR_NET, "%20s: node [%x] (%p) acquired item %p",
2009 		    __func__, node->nd_ID, node, item);
2010 		return (item);
2011 	}
2012 
2013 	/* Queue the request for later. */
2014 	ng_queue_rw(node, item, NGQRW_W);
2015 
2016 	return (NULL);
2017 }
2018 
2019 #if 0
2020 static __inline item_p
2021 ng_upgrade_write(node_p node, item_p item)
2022 {
2023 	struct ng_queue *ngq = &node->nd_input_queue;
2024 	KASSERT(node != &ng_deadnode,
2025 	    ("%s: working on deadnode", __func__));
2026 
2027 	NGI_SET_WRITER(item);
2028 
2029 	NG_QUEUE_LOCK(ngq);
2030 
2031 	/*
2032 	 * There will never be no readers as we are there ourselves.
2033 	 * Set the WRITER_ACTIVE flags ASAP to block out fast track readers.
2034 	 * The caller we are running from will call ng_leave_read()
2035 	 * soon, so we must account for that. We must leave again with the
2036 	 * READER lock. If we find other readers, then
2037 	 * queue the request for later. However "later" may be rignt now
2038 	 * if there are no readers. We don't really care if there are queued
2039 	 * items as we will bypass them anyhow.
2040 	 */
2041 	atomic_add_int(&ngq->q_flags, WRITER_ACTIVE - READER_INCREMENT);
2042 	if ((ngq->q_flags & (NGQ_WMASK & ~OP_PENDING)) == WRITER_ACTIVE) {
2043 		NG_QUEUE_UNLOCK(ngq);
2044 
2045 		/* It's just us, act on the item. */
2046 		/* will NOT drop writer lock when done */
2047 		ng_apply_item(node, item, 0);
2048 
2049 		/*
2050 		 * Having acted on the item, atomically
2051 		 * down grade back to READER and finish up
2052 	 	 */
2053 		atomic_add_int(&ngq->q_flags,
2054 		    READER_INCREMENT - WRITER_ACTIVE);
2055 
2056 		/* Our caller will call ng_leave_read() */
2057 		return;
2058 	}
2059 	/*
2060 	 * It's not just us active, so queue us AT THE HEAD.
2061 	 * "Why?" I hear you ask.
2062 	 * Put us at the head of the queue as we've already been
2063 	 * through it once. If there is nothing else waiting,
2064 	 * set the correct flags.
2065 	 */
2066 	if (STAILQ_EMPTY(&ngq->queue)) {
2067 		/* We've gone from, 0 to 1 item in the queue */
2068 		atomic_set_int(&ngq->q_flags, OP_PENDING);
2069 
2070 		CTR3(KTR_NET, "%20s: node [%x] (%p) set OP_PENDING", __func__,
2071 		    node->nd_ID, node);
2072 	};
2073 	STAILQ_INSERT_HEAD(&ngq->queue, item, el_next);
2074 	CTR4(KTR_NET, "%20s: node [%x] (%p) requeued item %p as WRITER",
2075 	    __func__, node->nd_ID, node, item );
2076 
2077 	/* Reverse what we did above. That downgrades us back to reader */
2078 	atomic_add_int(&ngq->q_flags, READER_INCREMENT - WRITER_ACTIVE);
2079 	if (QUEUE_ACTIVE(ngq) && NEXT_QUEUED_ITEM_CAN_PROCEED(ngq))
2080 		ng_worklist_add(node);
2081 	NG_QUEUE_UNLOCK(ngq);
2082 
2083 	return;
2084 }
2085 #endif
2086 
2087 /* Release reader lock. */
2088 static __inline void
2089 ng_leave_read(node_p node)
2090 {
2091 	atomic_subtract_rel_int(&node->nd_input_queue.q_flags, READER_INCREMENT);
2092 }
2093 
2094 /* Release writer lock. */
2095 static __inline void
2096 ng_leave_write(node_p node)
2097 {
2098 	atomic_clear_rel_int(&node->nd_input_queue.q_flags, WRITER_ACTIVE);
2099 }
2100 
2101 /* Purge node queue. Called on node shutdown. */
2102 static void
2103 ng_flush_input_queue(node_p node)
2104 {
2105 	struct ng_queue *ngq = &node->nd_input_queue;
2106 	item_p item;
2107 
2108 	NG_QUEUE_LOCK(ngq);
2109 	while ((item = STAILQ_FIRST(&ngq->queue)) != NULL) {
2110 		STAILQ_REMOVE_HEAD(&ngq->queue, el_next);
2111 		if (STAILQ_EMPTY(&ngq->queue))
2112 			atomic_clear_int(&ngq->q_flags, OP_PENDING);
2113 		NG_QUEUE_UNLOCK(ngq);
2114 
2115 		/* If the item is supplying a callback, call it with an error */
2116 		if (item->apply != NULL) {
2117 			if (item->depth == 1)
2118 				item->apply->error = ENOENT;
2119 			if (refcount_release(&item->apply->refs)) {
2120 				(*item->apply->apply)(item->apply->context,
2121 				    item->apply->error);
2122 			}
2123 		}
2124 		NG_FREE_ITEM(item);
2125 		NG_QUEUE_LOCK(ngq);
2126 	}
2127 	NG_QUEUE_UNLOCK(ngq);
2128 }
2129 
2130 /***********************************************************************
2131 * Externally visible method for sending or queueing messages or data.
2132 ***********************************************************************/
2133 
2134 /*
2135  * The module code should have filled out the item correctly by this stage:
2136  * Common:
2137  *    reference to destination node.
2138  *    Reference to destination rcv hook if relevant.
2139  *    apply pointer must be or NULL or reference valid struct ng_apply_info.
2140  * Data:
2141  *    pointer to mbuf
2142  * Control_Message:
2143  *    pointer to msg.
2144  *    ID of original sender node. (return address)
2145  * Function:
2146  *    Function pointer
2147  *    void * argument
2148  *    integer argument
2149  *
2150  * The nodes have several routines and macros to help with this task:
2151  */
2152 
2153 int
2154 ng_snd_item(item_p item, int flags)
2155 {
2156 	hook_p hook;
2157 	node_p node;
2158 	int queue, rw;
2159 	struct ng_queue *ngq;
2160 	int error = 0;
2161 
2162 	/* We are sending item, so it must be present! */
2163 	KASSERT(item != NULL, ("ng_snd_item: item is NULL"));
2164 
2165 #ifdef	NETGRAPH_DEBUG
2166 	_ngi_check(item, __FILE__, __LINE__);
2167 #endif
2168 
2169 	/* Item was sent once more, postpone apply() call. */
2170 	if (item->apply)
2171 		refcount_acquire(&item->apply->refs);
2172 
2173 	node = NGI_NODE(item);
2174 	/* Node is never optional. */
2175 	KASSERT(node != NULL, ("ng_snd_item: node is NULL"));
2176 
2177 	hook = NGI_HOOK(item);
2178 	/* Valid hook and mbuf are mandatory for data. */
2179 	if ((item->el_flags & NGQF_TYPE) == NGQF_DATA) {
2180 		KASSERT(hook != NULL, ("ng_snd_item: hook for data is NULL"));
2181 		if (NGI_M(item) == NULL)
2182 			ERROUT(EINVAL);
2183 		CHECK_DATA_MBUF(NGI_M(item));
2184 	}
2185 
2186 	/*
2187 	 * If the item or the node specifies single threading, force
2188 	 * writer semantics. Similarly, the node may say one hook always
2189 	 * produces writers. These are overrides.
2190 	 */
2191 	if (((item->el_flags & NGQF_RW) == NGQF_WRITER) ||
2192 	    (node->nd_flags & NGF_FORCE_WRITER) ||
2193 	    (hook && (hook->hk_flags & HK_FORCE_WRITER))) {
2194 		rw = NGQRW_W;
2195 	} else {
2196 		rw = NGQRW_R;
2197 	}
2198 
2199 	/*
2200 	 * If sender or receiver requests queued delivery, or call graph
2201 	 * loops back from outbound to inbound path, or stack usage
2202 	 * level is dangerous - enqueue message.
2203 	 */
2204 	if ((flags & NG_QUEUE) || (hook && (hook->hk_flags & HK_QUEUE))) {
2205 		queue = 1;
2206 	} else if (hook && (hook->hk_flags & HK_TO_INBOUND) &&
2207 	    curthread->td_ng_outbound) {
2208 		queue = 1;
2209 	} else {
2210 		queue = 0;
2211 #ifdef GET_STACK_USAGE
2212 		/*
2213 		 * Most of netgraph nodes have small stack consumption and
2214 		 * for them 25% of free stack space is more than enough.
2215 		 * Nodes/hooks with higher stack usage should be marked as
2216 		 * HI_STACK. For them 50% of stack will be guaranteed then.
2217 		 * XXX: Values 25% and 50% are completely empirical.
2218 		 */
2219 		size_t	st, su, sl;
2220 		GET_STACK_USAGE(st, su);
2221 		sl = st - su;
2222 		if ((sl * 4 < st) ||
2223 		    ((sl * 2 < st) && ((node->nd_flags & NGF_HI_STACK) ||
2224 		      (hook && (hook->hk_flags & HK_HI_STACK))))) {
2225 			queue = 1;
2226 		}
2227 #endif
2228 	}
2229 
2230 	if (queue) {
2231 		item->depth = 1;
2232 		/* Put it on the queue for that node*/
2233 		ng_queue_rw(node, item, rw);
2234 		return ((flags & NG_PROGRESS) ? EINPROGRESS : 0);
2235 	}
2236 
2237 	/*
2238 	 * We already decided how we will be queueud or treated.
2239 	 * Try get the appropriate operating permission.
2240 	 */
2241  	if (rw == NGQRW_R)
2242 		item = ng_acquire_read(node, item);
2243 	else
2244 		item = ng_acquire_write(node, item);
2245 
2246 	/* Item was queued while trying to get permission. */
2247 	if (item == NULL)
2248 		return ((flags & NG_PROGRESS) ? EINPROGRESS : 0);
2249 
2250 	NGI_GET_NODE(item, node); /* zaps stored node */
2251 
2252 	item->depth++;
2253 	error = ng_apply_item(node, item, rw); /* drops r/w lock when done */
2254 
2255 	/* If something is waiting on queue and ready, schedule it. */
2256 	ngq = &node->nd_input_queue;
2257 	if (QUEUE_ACTIVE(ngq)) {
2258 		NG_QUEUE_LOCK(ngq);
2259 		if (QUEUE_ACTIVE(ngq) && NEXT_QUEUED_ITEM_CAN_PROCEED(ngq))
2260 			ng_worklist_add(node);
2261 		NG_QUEUE_UNLOCK(ngq);
2262 	}
2263 
2264 	/*
2265 	 * Node may go away as soon as we remove the reference.
2266 	 * Whatever we do, DO NOT access the node again!
2267 	 */
2268 	NG_NODE_UNREF(node);
2269 
2270 	return (error);
2271 
2272 done:
2273 	/* If was not sent, apply callback here. */
2274 	if (item->apply != NULL) {
2275 		if (item->depth == 0 && error != 0)
2276 			item->apply->error = error;
2277 		if (refcount_release(&item->apply->refs)) {
2278 			(*item->apply->apply)(item->apply->context,
2279 			    item->apply->error);
2280 		}
2281 	}
2282 
2283 	NG_FREE_ITEM(item);
2284 	return (error);
2285 }
2286 
2287 /*
2288  * We have an item that was possibly queued somewhere.
2289  * It should contain all the information needed
2290  * to run it on the appropriate node/hook.
2291  * If there is apply pointer and we own the last reference, call apply().
2292  */
2293 static int
2294 ng_apply_item(node_p node, item_p item, int rw)
2295 {
2296 	hook_p  hook;
2297 	ng_rcvdata_t *rcvdata;
2298 	ng_rcvmsg_t *rcvmsg;
2299 	struct ng_apply_info *apply;
2300 	int	error = 0, depth;
2301 
2302 	/* Node and item are never optional. */
2303 	KASSERT(node != NULL, ("ng_apply_item: node is NULL"));
2304 	KASSERT(item != NULL, ("ng_apply_item: item is NULL"));
2305 
2306 	NGI_GET_HOOK(item, hook); /* clears stored hook */
2307 #ifdef	NETGRAPH_DEBUG
2308 	_ngi_check(item, __FILE__, __LINE__);
2309 #endif
2310 
2311 	apply = item->apply;
2312 	depth = item->depth;
2313 
2314 	switch (item->el_flags & NGQF_TYPE) {
2315 	case NGQF_DATA:
2316 		/*
2317 		 * Check things are still ok as when we were queued.
2318 		 */
2319 		KASSERT(hook != NULL, ("ng_apply_item: hook for data is NULL"));
2320 		if (NG_HOOK_NOT_VALID(hook) ||
2321 		    NG_NODE_NOT_VALID(node)) {
2322 			error = EIO;
2323 			NG_FREE_ITEM(item);
2324 			break;
2325 		}
2326 		/*
2327 		 * If no receive method, just silently drop it.
2328 		 * Give preference to the hook over-ride method
2329 		 */
2330 		if ((!(rcvdata = hook->hk_rcvdata))
2331 		&& (!(rcvdata = NG_HOOK_NODE(hook)->nd_type->rcvdata))) {
2332 			error = 0;
2333 			NG_FREE_ITEM(item);
2334 			break;
2335 		}
2336 		error = (*rcvdata)(hook, item);
2337 		break;
2338 	case NGQF_MESG:
2339 		if (hook && NG_HOOK_NOT_VALID(hook)) {
2340 			/*
2341 			 * The hook has been zapped then we can't use it.
2342 			 * Immediately drop its reference.
2343 			 * The message may not need it.
2344 			 */
2345 			NG_HOOK_UNREF(hook);
2346 			hook = NULL;
2347 		}
2348 		/*
2349 		 * Similarly, if the node is a zombie there is
2350 		 * nothing we can do with it, drop everything.
2351 		 */
2352 		if (NG_NODE_NOT_VALID(node)) {
2353 			TRAP_ERROR();
2354 			error = EINVAL;
2355 			NG_FREE_ITEM(item);
2356 			break;
2357 		}
2358 		/*
2359 		 * Call the appropriate message handler for the object.
2360 		 * It is up to the message handler to free the message.
2361 		 * If it's a generic message, handle it generically,
2362 		 * otherwise call the type's message handler (if it exists).
2363 		 * XXX (race). Remember that a queued message may
2364 		 * reference a node or hook that has just been
2365 		 * invalidated. It will exist as the queue code
2366 		 * is holding a reference, but..
2367 		 */
2368 		if ((NGI_MSG(item)->header.typecookie == NGM_GENERIC_COOKIE) &&
2369 		    ((NGI_MSG(item)->header.flags & NGF_RESP) == 0)) {
2370 			error = ng_generic_msg(node, item, hook);
2371 			break;
2372 		}
2373 		if (((!hook) || (!(rcvmsg = hook->hk_rcvmsg))) &&
2374 		    (!(rcvmsg = node->nd_type->rcvmsg))) {
2375 			TRAP_ERROR();
2376 			error = 0;
2377 			NG_FREE_ITEM(item);
2378 			break;
2379 		}
2380 		error = (*rcvmsg)(node, item, hook);
2381 		break;
2382 	case NGQF_FN:
2383 	case NGQF_FN2:
2384 		/*
2385 		 * In the case of the shutdown message we allow it to hit
2386 		 * even if the node is invalid.
2387 		 */
2388 		if (NG_NODE_NOT_VALID(node) &&
2389 		    NGI_FN(item) != &ng_rmnode) {
2390 			TRAP_ERROR();
2391 			error = EINVAL;
2392 			NG_FREE_ITEM(item);
2393 			break;
2394 		}
2395 		/* Same is about some internal functions and invalid hook. */
2396 		if (hook && NG_HOOK_NOT_VALID(hook) &&
2397 		    NGI_FN2(item) != &ng_con_part2 &&
2398 		    NGI_FN2(item) != &ng_con_part3 &&
2399 		    NGI_FN(item) != &ng_rmhook_part2) {
2400 			TRAP_ERROR();
2401 			error = EINVAL;
2402 			NG_FREE_ITEM(item);
2403 			break;
2404 		}
2405 
2406 		if ((item->el_flags & NGQF_TYPE) == NGQF_FN) {
2407 			(*NGI_FN(item))(node, hook, NGI_ARG1(item),
2408 			    NGI_ARG2(item));
2409 			NG_FREE_ITEM(item);
2410 		} else	/* it is NGQF_FN2 */
2411 			error = (*NGI_FN2(item))(node, item, hook);
2412 		break;
2413 	}
2414 	/*
2415 	 * We held references on some of the resources
2416 	 * that we took from the item. Now that we have
2417 	 * finished doing everything, drop those references.
2418 	 */
2419 	if (hook)
2420 		NG_HOOK_UNREF(hook);
2421 
2422  	if (rw == NGQRW_R)
2423 		ng_leave_read(node);
2424 	else
2425 		ng_leave_write(node);
2426 
2427 	/* Apply callback. */
2428 	if (apply != NULL) {
2429 		if (depth == 1 && error != 0)
2430 			apply->error = error;
2431 		if (refcount_release(&apply->refs))
2432 			(*apply->apply)(apply->context, apply->error);
2433 	}
2434 
2435 	return (error);
2436 }
2437 
2438 /***********************************************************************
2439  * Implement the 'generic' control messages
2440  ***********************************************************************/
2441 static int
2442 ng_generic_msg(node_p here, item_p item, hook_p lasthook)
2443 {
2444 	int error = 0;
2445 	struct ng_mesg *msg;
2446 	struct ng_mesg *resp = NULL;
2447 
2448 	NGI_GET_MSG(item, msg);
2449 	if (msg->header.typecookie != NGM_GENERIC_COOKIE) {
2450 		TRAP_ERROR();
2451 		error = EINVAL;
2452 		goto out;
2453 	}
2454 	switch (msg->header.cmd) {
2455 	case NGM_SHUTDOWN:
2456 		ng_rmnode(here, NULL, NULL, 0);
2457 		break;
2458 	case NGM_MKPEER:
2459 	    {
2460 		struct ngm_mkpeer *const mkp = (struct ngm_mkpeer *) msg->data;
2461 
2462 		if (msg->header.arglen != sizeof(*mkp)) {
2463 			TRAP_ERROR();
2464 			error = EINVAL;
2465 			break;
2466 		}
2467 		mkp->type[sizeof(mkp->type) - 1] = '\0';
2468 		mkp->ourhook[sizeof(mkp->ourhook) - 1] = '\0';
2469 		mkp->peerhook[sizeof(mkp->peerhook) - 1] = '\0';
2470 		error = ng_mkpeer(here, mkp->ourhook, mkp->peerhook, mkp->type);
2471 		break;
2472 	    }
2473 	case NGM_CONNECT:
2474 	    {
2475 		struct ngm_connect *const con =
2476 			(struct ngm_connect *) msg->data;
2477 		node_p node2;
2478 
2479 		if (msg->header.arglen != sizeof(*con)) {
2480 			TRAP_ERROR();
2481 			error = EINVAL;
2482 			break;
2483 		}
2484 		con->path[sizeof(con->path) - 1] = '\0';
2485 		con->ourhook[sizeof(con->ourhook) - 1] = '\0';
2486 		con->peerhook[sizeof(con->peerhook) - 1] = '\0';
2487 		/* Don't forget we get a reference.. */
2488 		error = ng_path2noderef(here, con->path, &node2, NULL);
2489 		if (error)
2490 			break;
2491 		error = ng_con_nodes(item, here, con->ourhook,
2492 		    node2, con->peerhook);
2493 		NG_NODE_UNREF(node2);
2494 		break;
2495 	    }
2496 	case NGM_NAME:
2497 	    {
2498 		struct ngm_name *const nam = (struct ngm_name *) msg->data;
2499 
2500 		if (msg->header.arglen != sizeof(*nam)) {
2501 			TRAP_ERROR();
2502 			error = EINVAL;
2503 			break;
2504 		}
2505 		nam->name[sizeof(nam->name) - 1] = '\0';
2506 		error = ng_name_node(here, nam->name);
2507 		break;
2508 	    }
2509 	case NGM_RMHOOK:
2510 	    {
2511 		struct ngm_rmhook *const rmh = (struct ngm_rmhook *) msg->data;
2512 		hook_p hook;
2513 
2514 		if (msg->header.arglen != sizeof(*rmh)) {
2515 			TRAP_ERROR();
2516 			error = EINVAL;
2517 			break;
2518 		}
2519 		rmh->ourhook[sizeof(rmh->ourhook) - 1] = '\0';
2520 		if ((hook = ng_findhook(here, rmh->ourhook)) != NULL)
2521 			ng_destroy_hook(hook);
2522 		break;
2523 	    }
2524 	case NGM_NODEINFO:
2525 	    {
2526 		struct nodeinfo *ni;
2527 
2528 		NG_MKRESPONSE(resp, msg, sizeof(*ni), M_NOWAIT);
2529 		if (resp == NULL) {
2530 			error = ENOMEM;
2531 			break;
2532 		}
2533 
2534 		/* Fill in node info */
2535 		ni = (struct nodeinfo *) resp->data;
2536 		if (NG_NODE_HAS_NAME(here))
2537 			strcpy(ni->name, NG_NODE_NAME(here));
2538 		strcpy(ni->type, here->nd_type->name);
2539 		ni->id = ng_node2ID(here);
2540 		ni->hooks = here->nd_numhooks;
2541 		break;
2542 	    }
2543 	case NGM_LISTHOOKS:
2544 	    {
2545 		const int nhooks = here->nd_numhooks;
2546 		struct hooklist *hl;
2547 		struct nodeinfo *ni;
2548 		hook_p hook;
2549 
2550 		/* Get response struct */
2551 		NG_MKRESPONSE(resp, msg, sizeof(*hl)
2552 		    + (nhooks * sizeof(struct linkinfo)), M_NOWAIT);
2553 		if (resp == NULL) {
2554 			error = ENOMEM;
2555 			break;
2556 		}
2557 		hl = (struct hooklist *) resp->data;
2558 		ni = &hl->nodeinfo;
2559 
2560 		/* Fill in node info */
2561 		if (NG_NODE_HAS_NAME(here))
2562 			strcpy(ni->name, NG_NODE_NAME(here));
2563 		strcpy(ni->type, here->nd_type->name);
2564 		ni->id = ng_node2ID(here);
2565 
2566 		/* Cycle through the linked list of hooks */
2567 		ni->hooks = 0;
2568 		LIST_FOREACH(hook, &here->nd_hooks, hk_hooks) {
2569 			struct linkinfo *const link = &hl->link[ni->hooks];
2570 
2571 			if (ni->hooks >= nhooks) {
2572 				log(LOG_ERR, "%s: number of %s changed\n",
2573 				    __func__, "hooks");
2574 				break;
2575 			}
2576 			if (NG_HOOK_NOT_VALID(hook))
2577 				continue;
2578 			strcpy(link->ourhook, NG_HOOK_NAME(hook));
2579 			strcpy(link->peerhook, NG_PEER_HOOK_NAME(hook));
2580 			if (NG_PEER_NODE_NAME(hook)[0] != '\0')
2581 				strcpy(link->nodeinfo.name,
2582 				    NG_PEER_NODE_NAME(hook));
2583 			strcpy(link->nodeinfo.type,
2584 			   NG_PEER_NODE(hook)->nd_type->name);
2585 			link->nodeinfo.id = ng_node2ID(NG_PEER_NODE(hook));
2586 			link->nodeinfo.hooks = NG_PEER_NODE(hook)->nd_numhooks;
2587 			ni->hooks++;
2588 		}
2589 		break;
2590 	    }
2591 
2592 	case NGM_LISTNAMES:
2593 	case NGM_LISTNODES:
2594 	    {
2595 		const int unnamed = (msg->header.cmd == NGM_LISTNODES);
2596 		struct namelist *nl;
2597 		node_p node;
2598 		int num = 0, i;
2599 
2600 		mtx_lock(&ng_namehash_mtx);
2601 		/* Count number of nodes */
2602 		for (i = 0; i < NG_NAME_HASH_SIZE; i++) {
2603 			LIST_FOREACH(node, &V_ng_name_hash[i], nd_nodes) {
2604 				if (NG_NODE_IS_VALID(node) &&
2605 				    (unnamed || NG_NODE_HAS_NAME(node))) {
2606 					num++;
2607 				}
2608 			}
2609 		}
2610 		mtx_unlock(&ng_namehash_mtx);
2611 
2612 		/* Get response struct */
2613 		NG_MKRESPONSE(resp, msg, sizeof(*nl)
2614 		    + (num * sizeof(struct nodeinfo)), M_NOWAIT);
2615 		if (resp == NULL) {
2616 			error = ENOMEM;
2617 			break;
2618 		}
2619 		nl = (struct namelist *) resp->data;
2620 
2621 		/* Cycle through the linked list of nodes */
2622 		nl->numnames = 0;
2623 		mtx_lock(&ng_namehash_mtx);
2624 		for (i = 0; i < NG_NAME_HASH_SIZE; i++) {
2625 			LIST_FOREACH(node, &V_ng_name_hash[i], nd_nodes) {
2626 				struct nodeinfo *const np =
2627 				    &nl->nodeinfo[nl->numnames];
2628 
2629 				if (NG_NODE_NOT_VALID(node))
2630 					continue;
2631 				if (!unnamed && (! NG_NODE_HAS_NAME(node)))
2632 					continue;
2633 				if (nl->numnames >= num) {
2634 					log(LOG_ERR, "%s: number of nodes changed\n",
2635 					    __func__);
2636 					break;
2637 				}
2638 				if (NG_NODE_HAS_NAME(node))
2639 					strcpy(np->name, NG_NODE_NAME(node));
2640 				strcpy(np->type, node->nd_type->name);
2641 				np->id = ng_node2ID(node);
2642 				np->hooks = node->nd_numhooks;
2643 				nl->numnames++;
2644 			}
2645 		}
2646 		mtx_unlock(&ng_namehash_mtx);
2647 		break;
2648 	    }
2649 
2650 	case NGM_LISTTYPES:
2651 	    {
2652 		struct typelist *tl;
2653 		struct ng_type *type;
2654 		int num = 0;
2655 
2656 		mtx_lock(&ng_typelist_mtx);
2657 		/* Count number of types */
2658 		LIST_FOREACH(type, &ng_typelist, types) {
2659 			num++;
2660 		}
2661 		mtx_unlock(&ng_typelist_mtx);
2662 
2663 		/* Get response struct */
2664 		NG_MKRESPONSE(resp, msg, sizeof(*tl)
2665 		    + (num * sizeof(struct typeinfo)), M_NOWAIT);
2666 		if (resp == NULL) {
2667 			error = ENOMEM;
2668 			break;
2669 		}
2670 		tl = (struct typelist *) resp->data;
2671 
2672 		/* Cycle through the linked list of types */
2673 		tl->numtypes = 0;
2674 		mtx_lock(&ng_typelist_mtx);
2675 		LIST_FOREACH(type, &ng_typelist, types) {
2676 			struct typeinfo *const tp = &tl->typeinfo[tl->numtypes];
2677 
2678 			if (tl->numtypes >= num) {
2679 				log(LOG_ERR, "%s: number of %s changed\n",
2680 				    __func__, "types");
2681 				break;
2682 			}
2683 			strcpy(tp->type_name, type->name);
2684 			tp->numnodes = type->refs - 1; /* don't count list */
2685 			tl->numtypes++;
2686 		}
2687 		mtx_unlock(&ng_typelist_mtx);
2688 		break;
2689 	    }
2690 
2691 	case NGM_BINARY2ASCII:
2692 	    {
2693 		int bufSize = 20 * 1024;	/* XXX hard coded constant */
2694 		const struct ng_parse_type *argstype;
2695 		const struct ng_cmdlist *c;
2696 		struct ng_mesg *binary, *ascii;
2697 
2698 		/* Data area must contain a valid netgraph message */
2699 		binary = (struct ng_mesg *)msg->data;
2700 		if (msg->header.arglen < sizeof(struct ng_mesg) ||
2701 		    (msg->header.arglen - sizeof(struct ng_mesg) <
2702 		    binary->header.arglen)) {
2703 			TRAP_ERROR();
2704 			error = EINVAL;
2705 			break;
2706 		}
2707 
2708 		/* Get a response message with lots of room */
2709 		NG_MKRESPONSE(resp, msg, sizeof(*ascii) + bufSize, M_NOWAIT);
2710 		if (resp == NULL) {
2711 			error = ENOMEM;
2712 			break;
2713 		}
2714 		ascii = (struct ng_mesg *)resp->data;
2715 
2716 		/* Copy binary message header to response message payload */
2717 		bcopy(binary, ascii, sizeof(*binary));
2718 
2719 		/* Find command by matching typecookie and command number */
2720 		for (c = here->nd_type->cmdlist;
2721 		    c != NULL && c->name != NULL; c++) {
2722 			if (binary->header.typecookie == c->cookie
2723 			    && binary->header.cmd == c->cmd)
2724 				break;
2725 		}
2726 		if (c == NULL || c->name == NULL) {
2727 			for (c = ng_generic_cmds; c->name != NULL; c++) {
2728 				if (binary->header.typecookie == c->cookie
2729 				    && binary->header.cmd == c->cmd)
2730 					break;
2731 			}
2732 			if (c->name == NULL) {
2733 				NG_FREE_MSG(resp);
2734 				error = ENOSYS;
2735 				break;
2736 			}
2737 		}
2738 
2739 		/* Convert command name to ASCII */
2740 		snprintf(ascii->header.cmdstr, sizeof(ascii->header.cmdstr),
2741 		    "%s", c->name);
2742 
2743 		/* Convert command arguments to ASCII */
2744 		argstype = (binary->header.flags & NGF_RESP) ?
2745 		    c->respType : c->mesgType;
2746 		if (argstype == NULL) {
2747 			*ascii->data = '\0';
2748 		} else {
2749 			if ((error = ng_unparse(argstype,
2750 			    (u_char *)binary->data,
2751 			    ascii->data, bufSize)) != 0) {
2752 				NG_FREE_MSG(resp);
2753 				break;
2754 			}
2755 		}
2756 
2757 		/* Return the result as struct ng_mesg plus ASCII string */
2758 		bufSize = strlen(ascii->data) + 1;
2759 		ascii->header.arglen = bufSize;
2760 		resp->header.arglen = sizeof(*ascii) + bufSize;
2761 		break;
2762 	    }
2763 
2764 	case NGM_ASCII2BINARY:
2765 	    {
2766 		int bufSize = 20 * 1024;	/* XXX hard coded constant */
2767 		const struct ng_cmdlist *c;
2768 		const struct ng_parse_type *argstype;
2769 		struct ng_mesg *ascii, *binary;
2770 		int off = 0;
2771 
2772 		/* Data area must contain at least a struct ng_mesg + '\0' */
2773 		ascii = (struct ng_mesg *)msg->data;
2774 		if ((msg->header.arglen < sizeof(*ascii) + 1) ||
2775 		    (ascii->header.arglen < 1) ||
2776 		    (msg->header.arglen < sizeof(*ascii) +
2777 		    ascii->header.arglen)) {
2778 			TRAP_ERROR();
2779 			error = EINVAL;
2780 			break;
2781 		}
2782 		ascii->data[ascii->header.arglen - 1] = '\0';
2783 
2784 		/* Get a response message with lots of room */
2785 		NG_MKRESPONSE(resp, msg, sizeof(*binary) + bufSize, M_NOWAIT);
2786 		if (resp == NULL) {
2787 			error = ENOMEM;
2788 			break;
2789 		}
2790 		binary = (struct ng_mesg *)resp->data;
2791 
2792 		/* Copy ASCII message header to response message payload */
2793 		bcopy(ascii, binary, sizeof(*ascii));
2794 
2795 		/* Find command by matching ASCII command string */
2796 		for (c = here->nd_type->cmdlist;
2797 		    c != NULL && c->name != NULL; c++) {
2798 			if (strcmp(ascii->header.cmdstr, c->name) == 0)
2799 				break;
2800 		}
2801 		if (c == NULL || c->name == NULL) {
2802 			for (c = ng_generic_cmds; c->name != NULL; c++) {
2803 				if (strcmp(ascii->header.cmdstr, c->name) == 0)
2804 					break;
2805 			}
2806 			if (c->name == NULL) {
2807 				NG_FREE_MSG(resp);
2808 				error = ENOSYS;
2809 				break;
2810 			}
2811 		}
2812 
2813 		/* Convert command name to binary */
2814 		binary->header.cmd = c->cmd;
2815 		binary->header.typecookie = c->cookie;
2816 
2817 		/* Convert command arguments to binary */
2818 		argstype = (binary->header.flags & NGF_RESP) ?
2819 		    c->respType : c->mesgType;
2820 		if (argstype == NULL) {
2821 			bufSize = 0;
2822 		} else {
2823 			if ((error = ng_parse(argstype, ascii->data,
2824 			    &off, (u_char *)binary->data, &bufSize)) != 0) {
2825 				NG_FREE_MSG(resp);
2826 				break;
2827 			}
2828 		}
2829 
2830 		/* Return the result */
2831 		binary->header.arglen = bufSize;
2832 		resp->header.arglen = sizeof(*binary) + bufSize;
2833 		break;
2834 	    }
2835 
2836 	case NGM_TEXT_CONFIG:
2837 	case NGM_TEXT_STATUS:
2838 		/*
2839 		 * This one is tricky as it passes the command down to the
2840 		 * actual node, even though it is a generic type command.
2841 		 * This means we must assume that the item/msg is already freed
2842 		 * when control passes back to us.
2843 		 */
2844 		if (here->nd_type->rcvmsg != NULL) {
2845 			NGI_MSG(item) = msg; /* put it back as we found it */
2846 			return((*here->nd_type->rcvmsg)(here, item, lasthook));
2847 		}
2848 		/* Fall through if rcvmsg not supported */
2849 	default:
2850 		TRAP_ERROR();
2851 		error = EINVAL;
2852 	}
2853 	/*
2854 	 * Sometimes a generic message may be statically allocated
2855 	 * to avoid problems with allocating when in tight memeory situations.
2856 	 * Don't free it if it is so.
2857 	 * I break them appart here, because erros may cause a free if the item
2858 	 * in which case we'd be doing it twice.
2859 	 * they are kept together above, to simplify freeing.
2860 	 */
2861 out:
2862 	NG_RESPOND_MSG(error, here, item, resp);
2863 	NG_FREE_MSG(msg);
2864 	return (error);
2865 }
2866 
2867 /************************************************************************
2868 			Queue element get/free routines
2869 ************************************************************************/
2870 
2871 uma_zone_t			ng_qzone;
2872 uma_zone_t			ng_qdzone;
2873 static int			numthreads = 0; /* number of queue threads */
2874 static int			maxalloc = 4096;/* limit the damage of a leak */
2875 static int			maxdata = 512;	/* limit the damage of a DoS */
2876 
2877 TUNABLE_INT("net.graph.threads", &numthreads);
2878 SYSCTL_INT(_net_graph, OID_AUTO, threads, CTLFLAG_RDTUN, &numthreads,
2879     0, "Number of queue processing threads");
2880 TUNABLE_INT("net.graph.maxalloc", &maxalloc);
2881 SYSCTL_INT(_net_graph, OID_AUTO, maxalloc, CTLFLAG_RDTUN, &maxalloc,
2882     0, "Maximum number of non-data queue items to allocate");
2883 TUNABLE_INT("net.graph.maxdata", &maxdata);
2884 SYSCTL_INT(_net_graph, OID_AUTO, maxdata, CTLFLAG_RDTUN, &maxdata,
2885     0, "Maximum number of data queue items to allocate");
2886 
2887 #ifdef	NETGRAPH_DEBUG
2888 static TAILQ_HEAD(, ng_item) ng_itemlist = TAILQ_HEAD_INITIALIZER(ng_itemlist);
2889 static int			allocated;	/* number of items malloc'd */
2890 #endif
2891 
2892 /*
2893  * Get a queue entry.
2894  * This is usually called when a packet first enters netgraph.
2895  * By definition, this is usually from an interrupt, or from a user.
2896  * Users are not so important, but try be quick for the times that it's
2897  * an interrupt.
2898  */
2899 static __inline item_p
2900 ng_alloc_item(int type, int flags)
2901 {
2902 	item_p item;
2903 
2904 	KASSERT(((type & ~NGQF_TYPE) == 0),
2905 	    ("%s: incorrect item type: %d", __func__, type));
2906 
2907 	item = uma_zalloc((type == NGQF_DATA)?ng_qdzone:ng_qzone,
2908 	    ((flags & NG_WAITOK) ? M_WAITOK : M_NOWAIT) | M_ZERO);
2909 
2910 	if (item) {
2911 		item->el_flags = type;
2912 #ifdef	NETGRAPH_DEBUG
2913 		mtx_lock(&ngq_mtx);
2914 		TAILQ_INSERT_TAIL(&ng_itemlist, item, all);
2915 		allocated++;
2916 		mtx_unlock(&ngq_mtx);
2917 #endif
2918 	}
2919 
2920 	return (item);
2921 }
2922 
2923 /*
2924  * Release a queue entry
2925  */
2926 void
2927 ng_free_item(item_p item)
2928 {
2929 	/*
2930 	 * The item may hold resources on it's own. We need to free
2931 	 * these before we can free the item. What they are depends upon
2932 	 * what kind of item it is. it is important that nodes zero
2933 	 * out pointers to resources that they remove from the item
2934 	 * or we release them again here.
2935 	 */
2936 	switch (item->el_flags & NGQF_TYPE) {
2937 	case NGQF_DATA:
2938 		/* If we have an mbuf still attached.. */
2939 		NG_FREE_M(_NGI_M(item));
2940 		break;
2941 	case NGQF_MESG:
2942 		_NGI_RETADDR(item) = 0;
2943 		NG_FREE_MSG(_NGI_MSG(item));
2944 		break;
2945 	case NGQF_FN:
2946 	case NGQF_FN2:
2947 		/* nothing to free really, */
2948 		_NGI_FN(item) = NULL;
2949 		_NGI_ARG1(item) = NULL;
2950 		_NGI_ARG2(item) = 0;
2951 		break;
2952 	}
2953 	/* If we still have a node or hook referenced... */
2954 	_NGI_CLR_NODE(item);
2955 	_NGI_CLR_HOOK(item);
2956 
2957 #ifdef	NETGRAPH_DEBUG
2958 	mtx_lock(&ngq_mtx);
2959 	TAILQ_REMOVE(&ng_itemlist, item, all);
2960 	allocated--;
2961 	mtx_unlock(&ngq_mtx);
2962 #endif
2963 	uma_zfree(((item->el_flags & NGQF_TYPE) == NGQF_DATA)?
2964 	    ng_qdzone:ng_qzone, item);
2965 }
2966 
2967 /*
2968  * Change type of the queue entry.
2969  * Possibly reallocates it from another UMA zone.
2970  */
2971 static __inline item_p
2972 ng_realloc_item(item_p pitem, int type, int flags)
2973 {
2974 	item_p item;
2975 	int from, to;
2976 
2977 	KASSERT((pitem != NULL), ("%s: can't reallocate NULL", __func__));
2978 	KASSERT(((type & ~NGQF_TYPE) == 0),
2979 	    ("%s: incorrect item type: %d", __func__, type));
2980 
2981 	from = ((pitem->el_flags & NGQF_TYPE) == NGQF_DATA);
2982 	to = (type == NGQF_DATA);
2983 	if (from != to) {
2984 		/* If reallocation is required do it and copy item. */
2985 		if ((item = ng_alloc_item(type, flags)) == NULL) {
2986 			ng_free_item(pitem);
2987 			return (NULL);
2988 		}
2989 		*item = *pitem;
2990 		ng_free_item(pitem);
2991 	} else
2992 		item = pitem;
2993 	item->el_flags = (item->el_flags & ~NGQF_TYPE) | type;
2994 
2995 	return (item);
2996 }
2997 
2998 /************************************************************************
2999 			Module routines
3000 ************************************************************************/
3001 
3002 /*
3003  * Handle the loading/unloading of a netgraph node type module
3004  */
3005 int
3006 ng_mod_event(module_t mod, int event, void *data)
3007 {
3008 	struct ng_type *const type = data;
3009 	int s, error = 0;
3010 
3011 	switch (event) {
3012 	case MOD_LOAD:
3013 
3014 		/* Register new netgraph node type */
3015 		s = splnet();
3016 		if ((error = ng_newtype(type)) != 0) {
3017 			splx(s);
3018 			break;
3019 		}
3020 
3021 		/* Call type specific code */
3022 		if (type->mod_event != NULL)
3023 			if ((error = (*type->mod_event)(mod, event, data))) {
3024 				mtx_lock(&ng_typelist_mtx);
3025 				type->refs--;	/* undo it */
3026 				LIST_REMOVE(type, types);
3027 				mtx_unlock(&ng_typelist_mtx);
3028 			}
3029 		splx(s);
3030 		break;
3031 
3032 	case MOD_UNLOAD:
3033 		s = splnet();
3034 		if (type->refs > 1) {		/* make sure no nodes exist! */
3035 			error = EBUSY;
3036 		} else {
3037 			if (type->refs == 0) {
3038 				/* failed load, nothing to undo */
3039 				splx(s);
3040 				break;
3041 			}
3042 			if (type->mod_event != NULL) {	/* check with type */
3043 				error = (*type->mod_event)(mod, event, data);
3044 				if (error != 0) {	/* type refuses.. */
3045 					splx(s);
3046 					break;
3047 				}
3048 			}
3049 			mtx_lock(&ng_typelist_mtx);
3050 			LIST_REMOVE(type, types);
3051 			mtx_unlock(&ng_typelist_mtx);
3052 		}
3053 		splx(s);
3054 		break;
3055 
3056 	default:
3057 		if (type->mod_event != NULL)
3058 			error = (*type->mod_event)(mod, event, data);
3059 		else
3060 			error = EOPNOTSUPP;		/* XXX ? */
3061 		break;
3062 	}
3063 	return (error);
3064 }
3065 
3066 #ifdef VIMAGE
3067 static void
3068 vnet_netgraph_uninit(const void *unused __unused)
3069 {
3070 	node_p node = NULL, last_killed = NULL;
3071 	int i;
3072 
3073 	do {
3074 		/* Find a node to kill */
3075 		mtx_lock(&ng_namehash_mtx);
3076 		for (i = 0; i < NG_NAME_HASH_SIZE; i++) {
3077 			LIST_FOREACH(node, &V_ng_name_hash[i], nd_nodes) {
3078 				if (node != &ng_deadnode) {
3079 					NG_NODE_REF(node);
3080 					break;
3081 				}
3082 			}
3083 			if (node != NULL)
3084 				break;
3085 		}
3086 		mtx_unlock(&ng_namehash_mtx);
3087 
3088 		/* Attempt to kill it only if it is a regular node */
3089 		if (node != NULL) {
3090 			if (node == last_killed) {
3091 				/* This should never happen */
3092 				printf("ng node %s needs"
3093 				    "NGF_REALLY_DIE\n", node->nd_name);
3094 				if (node->nd_flags & NGF_REALLY_DIE)
3095 					panic("ng node %s won't die",
3096 					    node->nd_name);
3097 				node->nd_flags |= NGF_REALLY_DIE;
3098 			}
3099 			ng_rmnode(node, NULL, NULL, 0);
3100 			NG_NODE_UNREF(node);
3101 			last_killed = node;
3102 		}
3103 	} while (node != NULL);
3104 }
3105 VNET_SYSUNINIT(vnet_netgraph_uninit, SI_SUB_PROTO_IFATTACHDOMAIN, SI_ORDER_ANY,
3106     vnet_netgraph_uninit, NULL);
3107 #endif /* VIMAGE */
3108 
3109 /*
3110  * Handle loading and unloading for this code.
3111  * The only thing we need to link into is the NETISR strucure.
3112  */
3113 static int
3114 ngb_mod_event(module_t mod, int event, void *data)
3115 {
3116 	struct proc *p;
3117 	struct thread *td;
3118 	int i, error = 0;
3119 
3120 	switch (event) {
3121 	case MOD_LOAD:
3122 		/* Initialize everything. */
3123 		NG_WORKLIST_LOCK_INIT();
3124 		mtx_init(&ng_typelist_mtx, "netgraph types mutex", NULL,
3125 		    MTX_DEF);
3126 		mtx_init(&ng_idhash_mtx, "netgraph idhash mutex", NULL,
3127 		    MTX_DEF);
3128 		mtx_init(&ng_namehash_mtx, "netgraph namehash mutex", NULL,
3129 		    MTX_DEF);
3130 		mtx_init(&ng_topo_mtx, "netgraph topology mutex", NULL,
3131 		    MTX_DEF);
3132 #ifdef	NETGRAPH_DEBUG
3133 		mtx_init(&ng_nodelist_mtx, "netgraph nodelist mutex", NULL,
3134 		    MTX_DEF);
3135 		mtx_init(&ngq_mtx, "netgraph item list mutex", NULL,
3136 		    MTX_DEF);
3137 #endif
3138 		ng_qzone = uma_zcreate("NetGraph items", sizeof(struct ng_item),
3139 		    NULL, NULL, NULL, NULL, UMA_ALIGN_CACHE, 0);
3140 		uma_zone_set_max(ng_qzone, maxalloc);
3141 		ng_qdzone = uma_zcreate("NetGraph data items", sizeof(struct ng_item),
3142 		    NULL, NULL, NULL, NULL, UMA_ALIGN_CACHE, 0);
3143 		uma_zone_set_max(ng_qdzone, maxdata);
3144 		/* Autoconfigure number of threads. */
3145 		if (numthreads <= 0)
3146 			numthreads = mp_ncpus;
3147 		/* Create threads. */
3148     		p = NULL; /* start with no process */
3149 		for (i = 0; i < numthreads; i++) {
3150 			if (kproc_kthread_add(ngthread, NULL, &p, &td,
3151 			    RFHIGHPID, 0, "ng_queue", "ng_queue%d", i)) {
3152 				numthreads = i;
3153 				break;
3154 			}
3155 		}
3156 		break;
3157 	case MOD_UNLOAD:
3158 		/* You can't unload it because an interface may be using it. */
3159 		error = EBUSY;
3160 		break;
3161 	default:
3162 		error = EOPNOTSUPP;
3163 		break;
3164 	}
3165 	return (error);
3166 }
3167 
3168 static moduledata_t netgraph_mod = {
3169 	"netgraph",
3170 	ngb_mod_event,
3171 	(NULL)
3172 };
3173 DECLARE_MODULE(netgraph, netgraph_mod, SI_SUB_NETGRAPH, SI_ORDER_MIDDLE);
3174 SYSCTL_NODE(_net, OID_AUTO, graph, CTLFLAG_RW, 0, "netgraph Family");
3175 SYSCTL_INT(_net_graph, OID_AUTO, abi_version, CTLFLAG_RD, 0, NG_ABI_VERSION,"");
3176 SYSCTL_INT(_net_graph, OID_AUTO, msg_version, CTLFLAG_RD, 0, NG_VERSION, "");
3177 
3178 #ifdef	NETGRAPH_DEBUG
3179 void
3180 dumphook (hook_p hook, char *file, int line)
3181 {
3182 	printf("hook: name %s, %d refs, Last touched:\n",
3183 		_NG_HOOK_NAME(hook), hook->hk_refs);
3184 	printf("	Last active @ %s, line %d\n",
3185 		hook->lastfile, hook->lastline);
3186 	if (line) {
3187 		printf(" problem discovered at file %s, line %d\n", file, line);
3188 	}
3189 }
3190 
3191 void
3192 dumpnode(node_p node, char *file, int line)
3193 {
3194 	printf("node: ID [%x]: type '%s', %d hooks, flags 0x%x, %d refs, %s:\n",
3195 		_NG_NODE_ID(node), node->nd_type->name,
3196 		node->nd_numhooks, node->nd_flags,
3197 		node->nd_refs, node->nd_name);
3198 	printf("	Last active @ %s, line %d\n",
3199 		node->lastfile, node->lastline);
3200 	if (line) {
3201 		printf(" problem discovered at file %s, line %d\n", file, line);
3202 	}
3203 }
3204 
3205 void
3206 dumpitem(item_p item, char *file, int line)
3207 {
3208 	printf(" ACTIVE item, last used at %s, line %d",
3209 		item->lastfile, item->lastline);
3210 	switch(item->el_flags & NGQF_TYPE) {
3211 	case NGQF_DATA:
3212 		printf(" - [data]\n");
3213 		break;
3214 	case NGQF_MESG:
3215 		printf(" - retaddr[%d]:\n", _NGI_RETADDR(item));
3216 		break;
3217 	case NGQF_FN:
3218 		printf(" - fn@%p (%p, %p, %p, %d (%x))\n",
3219 			_NGI_FN(item),
3220 			_NGI_NODE(item),
3221 			_NGI_HOOK(item),
3222 			item->body.fn.fn_arg1,
3223 			item->body.fn.fn_arg2,
3224 			item->body.fn.fn_arg2);
3225 		break;
3226 	case NGQF_FN2:
3227 		printf(" - fn2@%p (%p, %p, %p, %d (%x))\n",
3228 			_NGI_FN2(item),
3229 			_NGI_NODE(item),
3230 			_NGI_HOOK(item),
3231 			item->body.fn.fn_arg1,
3232 			item->body.fn.fn_arg2,
3233 			item->body.fn.fn_arg2);
3234 		break;
3235 	}
3236 	if (line) {
3237 		printf(" problem discovered at file %s, line %d\n", file, line);
3238 		if (_NGI_NODE(item)) {
3239 			printf("node %p ([%x])\n",
3240 				_NGI_NODE(item), ng_node2ID(_NGI_NODE(item)));
3241 		}
3242 	}
3243 }
3244 
3245 static void
3246 ng_dumpitems(void)
3247 {
3248 	item_p item;
3249 	int i = 1;
3250 	TAILQ_FOREACH(item, &ng_itemlist, all) {
3251 		printf("[%d] ", i++);
3252 		dumpitem(item, NULL, 0);
3253 	}
3254 }
3255 
3256 static void
3257 ng_dumpnodes(void)
3258 {
3259 	node_p node;
3260 	int i = 1;
3261 	mtx_lock(&ng_nodelist_mtx);
3262 	SLIST_FOREACH(node, &ng_allnodes, nd_all) {
3263 		printf("[%d] ", i++);
3264 		dumpnode(node, NULL, 0);
3265 	}
3266 	mtx_unlock(&ng_nodelist_mtx);
3267 }
3268 
3269 static void
3270 ng_dumphooks(void)
3271 {
3272 	hook_p hook;
3273 	int i = 1;
3274 	mtx_lock(&ng_nodelist_mtx);
3275 	SLIST_FOREACH(hook, &ng_allhooks, hk_all) {
3276 		printf("[%d] ", i++);
3277 		dumphook(hook, NULL, 0);
3278 	}
3279 	mtx_unlock(&ng_nodelist_mtx);
3280 }
3281 
3282 static int
3283 sysctl_debug_ng_dump_items(SYSCTL_HANDLER_ARGS)
3284 {
3285 	int error;
3286 	int val;
3287 	int i;
3288 
3289 	val = allocated;
3290 	i = 1;
3291 	error = sysctl_handle_int(oidp, &val, 0, req);
3292 	if (error != 0 || req->newptr == NULL)
3293 		return (error);
3294 	if (val == 42) {
3295 		ng_dumpitems();
3296 		ng_dumpnodes();
3297 		ng_dumphooks();
3298 	}
3299 	return (0);
3300 }
3301 
3302 SYSCTL_PROC(_debug, OID_AUTO, ng_dump_items, CTLTYPE_INT | CTLFLAG_RW,
3303     0, sizeof(int), sysctl_debug_ng_dump_items, "I", "Number of allocated items");
3304 #endif	/* NETGRAPH_DEBUG */
3305 
3306 
3307 /***********************************************************************
3308 * Worklist routines
3309 **********************************************************************/
3310 /*
3311  * Pick a node off the list of nodes with work,
3312  * try get an item to process off it. Remove the node from the list.
3313  */
3314 static void
3315 ngthread(void *arg)
3316 {
3317 	for (;;) {
3318 		node_p  node;
3319 
3320 		/* Get node from the worklist. */
3321 		NG_WORKLIST_LOCK();
3322 		while ((node = STAILQ_FIRST(&ng_worklist)) == NULL)
3323 			NG_WORKLIST_SLEEP();
3324 		STAILQ_REMOVE_HEAD(&ng_worklist, nd_input_queue.q_work);
3325 		NG_WORKLIST_UNLOCK();
3326 		CURVNET_SET(node->nd_vnet);
3327 		CTR3(KTR_NET, "%20s: node [%x] (%p) taken off worklist",
3328 		    __func__, node->nd_ID, node);
3329 		/*
3330 		 * We have the node. We also take over the reference
3331 		 * that the list had on it.
3332 		 * Now process as much as you can, until it won't
3333 		 * let you have another item off the queue.
3334 		 * All this time, keep the reference
3335 		 * that lets us be sure that the node still exists.
3336 		 * Let the reference go at the last minute.
3337 		 */
3338 		for (;;) {
3339 			item_p item;
3340 			int rw;
3341 
3342 			NG_QUEUE_LOCK(&node->nd_input_queue);
3343 			item = ng_dequeue(node, &rw);
3344 			if (item == NULL) {
3345 				node->nd_input_queue.q_flags2 &= ~NGQ2_WORKQ;
3346 				NG_QUEUE_UNLOCK(&node->nd_input_queue);
3347 				break; /* go look for another node */
3348 			} else {
3349 				NG_QUEUE_UNLOCK(&node->nd_input_queue);
3350 				NGI_GET_NODE(item, node); /* zaps stored node */
3351 				ng_apply_item(node, item, rw);
3352 				NG_NODE_UNREF(node);
3353 			}
3354 		}
3355 		NG_NODE_UNREF(node);
3356 		CURVNET_RESTORE();
3357 	}
3358 }
3359 
3360 /*
3361  * XXX
3362  * It's posible that a debugging NG_NODE_REF may need
3363  * to be outside the mutex zone
3364  */
3365 static void
3366 ng_worklist_add(node_p node)
3367 {
3368 
3369 	mtx_assert(&node->nd_input_queue.q_mtx, MA_OWNED);
3370 
3371 	if ((node->nd_input_queue.q_flags2 & NGQ2_WORKQ) == 0) {
3372 		/*
3373 		 * If we are not already on the work queue,
3374 		 * then put us on.
3375 		 */
3376 		node->nd_input_queue.q_flags2 |= NGQ2_WORKQ;
3377 		NG_NODE_REF(node); /* XXX fafe in mutex? */
3378 		NG_WORKLIST_LOCK();
3379 		STAILQ_INSERT_TAIL(&ng_worklist, node, nd_input_queue.q_work);
3380 		NG_WORKLIST_UNLOCK();
3381 		CTR3(KTR_NET, "%20s: node [%x] (%p) put on worklist", __func__,
3382 		    node->nd_ID, node);
3383 		NG_WORKLIST_WAKEUP();
3384 	} else {
3385 		CTR3(KTR_NET, "%20s: node [%x] (%p) already on worklist",
3386 		    __func__, node->nd_ID, node);
3387 	}
3388 }
3389 
3390 
3391 /***********************************************************************
3392 * Externally useable functions to set up a queue item ready for sending
3393 ***********************************************************************/
3394 
3395 #ifdef	NETGRAPH_DEBUG
3396 #define	ITEM_DEBUG_CHECKS						\
3397 	do {								\
3398 		if (NGI_NODE(item) ) {					\
3399 			printf("item already has node");		\
3400 			kdb_enter(KDB_WHY_NETGRAPH, "has node");	\
3401 			NGI_CLR_NODE(item);				\
3402 		}							\
3403 		if (NGI_HOOK(item) ) {					\
3404 			printf("item already has hook");		\
3405 			kdb_enter(KDB_WHY_NETGRAPH, "has hook");	\
3406 			NGI_CLR_HOOK(item);				\
3407 		}							\
3408 	} while (0)
3409 #else
3410 #define ITEM_DEBUG_CHECKS
3411 #endif
3412 
3413 /*
3414  * Put mbuf into the item.
3415  * Hook and node references will be removed when the item is dequeued.
3416  * (or equivalent)
3417  * (XXX) Unsafe because no reference held by peer on remote node.
3418  * remote node might go away in this timescale.
3419  * We know the hooks can't go away because that would require getting
3420  * a writer item on both nodes and we must have at least a  reader
3421  * here to be able to do this.
3422  * Note that the hook loaded is the REMOTE hook.
3423  *
3424  * This is possibly in the critical path for new data.
3425  */
3426 item_p
3427 ng_package_data(struct mbuf *m, int flags)
3428 {
3429 	item_p item;
3430 
3431 	if ((item = ng_alloc_item(NGQF_DATA, flags)) == NULL) {
3432 		NG_FREE_M(m);
3433 		return (NULL);
3434 	}
3435 	ITEM_DEBUG_CHECKS;
3436 	item->el_flags |= NGQF_READER;
3437 	NGI_M(item) = m;
3438 	return (item);
3439 }
3440 
3441 /*
3442  * Allocate a queue item and put items into it..
3443  * Evaluate the address as this will be needed to queue it and
3444  * to work out what some of the fields should be.
3445  * Hook and node references will be removed when the item is dequeued.
3446  * (or equivalent)
3447  */
3448 item_p
3449 ng_package_msg(struct ng_mesg *msg, int flags)
3450 {
3451 	item_p item;
3452 
3453 	if ((item = ng_alloc_item(NGQF_MESG, flags)) == NULL) {
3454 		NG_FREE_MSG(msg);
3455 		return (NULL);
3456 	}
3457 	ITEM_DEBUG_CHECKS;
3458 	/* Messages items count as writers unless explicitly exempted. */
3459 	if (msg->header.cmd & NGM_READONLY)
3460 		item->el_flags |= NGQF_READER;
3461 	else
3462 		item->el_flags |= NGQF_WRITER;
3463 	/*
3464 	 * Set the current lasthook into the queue item
3465 	 */
3466 	NGI_MSG(item) = msg;
3467 	NGI_RETADDR(item) = 0;
3468 	return (item);
3469 }
3470 
3471 
3472 
3473 #define SET_RETADDR(item, here, retaddr)				\
3474 	do {	/* Data or fn items don't have retaddrs */		\
3475 		if ((item->el_flags & NGQF_TYPE) == NGQF_MESG) {	\
3476 			if (retaddr) {					\
3477 				NGI_RETADDR(item) = retaddr;		\
3478 			} else {					\
3479 				/*					\
3480 				 * The old return address should be ok.	\
3481 				 * If there isn't one, use the address	\
3482 				 * here.				\
3483 				 */					\
3484 				if (NGI_RETADDR(item) == 0) {		\
3485 					NGI_RETADDR(item)		\
3486 						= ng_node2ID(here);	\
3487 				}					\
3488 			}						\
3489 		}							\
3490 	} while (0)
3491 
3492 int
3493 ng_address_hook(node_p here, item_p item, hook_p hook, ng_ID_t retaddr)
3494 {
3495 	hook_p peer;
3496 	node_p peernode;
3497 	ITEM_DEBUG_CHECKS;
3498 	/*
3499 	 * Quick sanity check..
3500 	 * Since a hook holds a reference on it's node, once we know
3501 	 * that the peer is still connected (even if invalid,) we know
3502 	 * that the peer node is present, though maybe invalid.
3503 	 */
3504 	if ((hook == NULL) ||
3505 	    NG_HOOK_NOT_VALID(hook) ||
3506 	    NG_HOOK_NOT_VALID(peer = NG_HOOK_PEER(hook)) ||
3507 	    NG_NODE_NOT_VALID(peernode = NG_PEER_NODE(hook))) {
3508 		NG_FREE_ITEM(item);
3509 		TRAP_ERROR();
3510 		return (ENETDOWN);
3511 	}
3512 
3513 	/*
3514 	 * Transfer our interest to the other (peer) end.
3515 	 */
3516 	NG_HOOK_REF(peer);
3517 	NG_NODE_REF(peernode);
3518 	NGI_SET_HOOK(item, peer);
3519 	NGI_SET_NODE(item, peernode);
3520 	SET_RETADDR(item, here, retaddr);
3521 	return (0);
3522 }
3523 
3524 int
3525 ng_address_path(node_p here, item_p item, char *address, ng_ID_t retaddr)
3526 {
3527 	node_p	dest = NULL;
3528 	hook_p	hook = NULL;
3529 	int	error;
3530 
3531 	ITEM_DEBUG_CHECKS;
3532 	/*
3533 	 * Note that ng_path2noderef increments the reference count
3534 	 * on the node for us if it finds one. So we don't have to.
3535 	 */
3536 	error = ng_path2noderef(here, address, &dest, &hook);
3537 	if (error) {
3538 		NG_FREE_ITEM(item);
3539 		return (error);
3540 	}
3541 	NGI_SET_NODE(item, dest);
3542 	if ( hook) {
3543 		NG_HOOK_REF(hook);	/* don't let it go while on the queue */
3544 		NGI_SET_HOOK(item, hook);
3545 	}
3546 	SET_RETADDR(item, here, retaddr);
3547 	return (0);
3548 }
3549 
3550 int
3551 ng_address_ID(node_p here, item_p item, ng_ID_t ID, ng_ID_t retaddr)
3552 {
3553 	node_p dest;
3554 
3555 	ITEM_DEBUG_CHECKS;
3556 	/*
3557 	 * Find the target node.
3558 	 */
3559 	dest = ng_ID2noderef(ID); /* GETS REFERENCE! */
3560 	if (dest == NULL) {
3561 		NG_FREE_ITEM(item);
3562 		TRAP_ERROR();
3563 		return(EINVAL);
3564 	}
3565 	/* Fill out the contents */
3566 	NGI_SET_NODE(item, dest);
3567 	NGI_CLR_HOOK(item);
3568 	SET_RETADDR(item, here, retaddr);
3569 	return (0);
3570 }
3571 
3572 /*
3573  * special case to send a message to self (e.g. destroy node)
3574  * Possibly indicate an arrival hook too.
3575  * Useful for removing that hook :-)
3576  */
3577 item_p
3578 ng_package_msg_self(node_p here, hook_p hook, struct ng_mesg *msg)
3579 {
3580 	item_p item;
3581 
3582 	/*
3583 	 * Find the target node.
3584 	 * If there is a HOOK argument, then use that in preference
3585 	 * to the address.
3586 	 */
3587 	if ((item = ng_alloc_item(NGQF_MESG, NG_NOFLAGS)) == NULL) {
3588 		NG_FREE_MSG(msg);
3589 		return (NULL);
3590 	}
3591 
3592 	/* Fill out the contents */
3593 	item->el_flags |= NGQF_WRITER;
3594 	NG_NODE_REF(here);
3595 	NGI_SET_NODE(item, here);
3596 	if (hook) {
3597 		NG_HOOK_REF(hook);
3598 		NGI_SET_HOOK(item, hook);
3599 	}
3600 	NGI_MSG(item) = msg;
3601 	NGI_RETADDR(item) = ng_node2ID(here);
3602 	return (item);
3603 }
3604 
3605 /*
3606  * Send ng_item_fn function call to the specified node.
3607  */
3608 
3609 int
3610 ng_send_fn(node_p node, hook_p hook, ng_item_fn *fn, void * arg1, int arg2)
3611 {
3612 
3613 	return ng_send_fn1(node, hook, fn, arg1, arg2, NG_NOFLAGS);
3614 }
3615 
3616 int
3617 ng_send_fn1(node_p node, hook_p hook, ng_item_fn *fn, void * arg1, int arg2,
3618 	int flags)
3619 {
3620 	item_p item;
3621 
3622 	if ((item = ng_alloc_item(NGQF_FN, flags)) == NULL) {
3623 		return (ENOMEM);
3624 	}
3625 	item->el_flags |= NGQF_WRITER;
3626 	NG_NODE_REF(node); /* and one for the item */
3627 	NGI_SET_NODE(item, node);
3628 	if (hook) {
3629 		NG_HOOK_REF(hook);
3630 		NGI_SET_HOOK(item, hook);
3631 	}
3632 	NGI_FN(item) = fn;
3633 	NGI_ARG1(item) = arg1;
3634 	NGI_ARG2(item) = arg2;
3635 	return(ng_snd_item(item, flags));
3636 }
3637 
3638 /*
3639  * Send ng_item_fn2 function call to the specified node.
3640  *
3641  * If an optional pitem parameter is supplied, its apply
3642  * callback will be copied to the new item. If also NG_REUSE_ITEM
3643  * flag is set, no new item will be allocated, but pitem will
3644  * be used.
3645  */
3646 int
3647 ng_send_fn2(node_p node, hook_p hook, item_p pitem, ng_item_fn2 *fn, void *arg1,
3648 	int arg2, int flags)
3649 {
3650 	item_p item;
3651 
3652 	KASSERT((pitem != NULL || (flags & NG_REUSE_ITEM) == 0),
3653 	    ("%s: NG_REUSE_ITEM but no pitem", __func__));
3654 
3655 	/*
3656 	 * Allocate a new item if no supplied or
3657 	 * if we can't use supplied one.
3658 	 */
3659 	if (pitem == NULL || (flags & NG_REUSE_ITEM) == 0) {
3660 		if ((item = ng_alloc_item(NGQF_FN2, flags)) == NULL)
3661 			return (ENOMEM);
3662 		if (pitem != NULL)
3663 			item->apply = pitem->apply;
3664 	} else {
3665 		if ((item = ng_realloc_item(pitem, NGQF_FN2, flags)) == NULL)
3666 			return (ENOMEM);
3667 	}
3668 
3669 	item->el_flags = (item->el_flags & ~NGQF_RW) | NGQF_WRITER;
3670 	NG_NODE_REF(node); /* and one for the item */
3671 	NGI_SET_NODE(item, node);
3672 	if (hook) {
3673 		NG_HOOK_REF(hook);
3674 		NGI_SET_HOOK(item, hook);
3675 	}
3676 	NGI_FN2(item) = fn;
3677 	NGI_ARG1(item) = arg1;
3678 	NGI_ARG2(item) = arg2;
3679 	return(ng_snd_item(item, flags));
3680 }
3681 
3682 /*
3683  * Official timeout routines for Netgraph nodes.
3684  */
3685 static void
3686 ng_callout_trampoline(void *arg)
3687 {
3688 	item_p item = arg;
3689 
3690 	CURVNET_SET(NGI_NODE(item)->nd_vnet);
3691 	ng_snd_item(item, 0);
3692 	CURVNET_RESTORE();
3693 }
3694 
3695 
3696 int
3697 ng_callout(struct callout *c, node_p node, hook_p hook, int ticks,
3698     ng_item_fn *fn, void * arg1, int arg2)
3699 {
3700 	item_p item, oitem;
3701 
3702 	if ((item = ng_alloc_item(NGQF_FN, NG_NOFLAGS)) == NULL)
3703 		return (ENOMEM);
3704 
3705 	item->el_flags |= NGQF_WRITER;
3706 	NG_NODE_REF(node);		/* and one for the item */
3707 	NGI_SET_NODE(item, node);
3708 	if (hook) {
3709 		NG_HOOK_REF(hook);
3710 		NGI_SET_HOOK(item, hook);
3711 	}
3712 	NGI_FN(item) = fn;
3713 	NGI_ARG1(item) = arg1;
3714 	NGI_ARG2(item) = arg2;
3715 	oitem = c->c_arg;
3716 	if (callout_reset(c, ticks, &ng_callout_trampoline, item) == 1 &&
3717 	    oitem != NULL)
3718 		NG_FREE_ITEM(oitem);
3719 	return (0);
3720 }
3721 
3722 /* A special modified version of untimeout() */
3723 int
3724 ng_uncallout(struct callout *c, node_p node)
3725 {
3726 	item_p item;
3727 	int rval;
3728 
3729 	KASSERT(c != NULL, ("ng_uncallout: NULL callout"));
3730 	KASSERT(node != NULL, ("ng_uncallout: NULL node"));
3731 
3732 	rval = callout_stop(c);
3733 	item = c->c_arg;
3734 	/* Do an extra check */
3735 	if ((rval > 0) && (c->c_func == &ng_callout_trampoline) &&
3736 	    (NGI_NODE(item) == node)) {
3737 		/*
3738 		 * We successfully removed it from the queue before it ran
3739 		 * So now we need to unreference everything that was
3740 		 * given extra references. (NG_FREE_ITEM does this).
3741 		 */
3742 		NG_FREE_ITEM(item);
3743 	}
3744 	c->c_arg = NULL;
3745 
3746 	return (rval);
3747 }
3748 
3749 /*
3750  * Set the address, if none given, give the node here.
3751  */
3752 void
3753 ng_replace_retaddr(node_p here, item_p item, ng_ID_t retaddr)
3754 {
3755 	if (retaddr) {
3756 		NGI_RETADDR(item) = retaddr;
3757 	} else {
3758 		/*
3759 		 * The old return address should be ok.
3760 		 * If there isn't one, use the address here.
3761 		 */
3762 		NGI_RETADDR(item) = ng_node2ID(here);
3763 	}
3764 }
3765 
3766 #define TESTING
3767 #ifdef TESTING
3768 /* just test all the macros */
3769 void
3770 ng_macro_test(item_p item);
3771 void
3772 ng_macro_test(item_p item)
3773 {
3774 	node_p node = NULL;
3775 	hook_p hook = NULL;
3776 	struct mbuf *m;
3777 	struct ng_mesg *msg;
3778 	ng_ID_t retaddr;
3779 	int	error;
3780 
3781 	NGI_GET_M(item, m);
3782 	NGI_GET_MSG(item, msg);
3783 	retaddr = NGI_RETADDR(item);
3784 	NG_SEND_DATA(error, hook, m, NULL);
3785 	NG_SEND_DATA_ONLY(error, hook, m);
3786 	NG_FWD_NEW_DATA(error, item, hook, m);
3787 	NG_FWD_ITEM_HOOK(error, item, hook);
3788 	NG_SEND_MSG_HOOK(error, node, msg, hook, retaddr);
3789 	NG_SEND_MSG_ID(error, node, msg, retaddr, retaddr);
3790 	NG_SEND_MSG_PATH(error, node, msg, ".:", retaddr);
3791 	NG_FWD_MSG_HOOK(error, node, item, hook, retaddr);
3792 }
3793 #endif /* TESTING */
3794 
3795