xref: /freebsd/sys/netgraph/ng_base.c (revision 9336e0699bda8a301cd2bfa37106b6ec5e32012e)
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 
64 #include <net/netisr.h>
65 
66 #include <netgraph/ng_message.h>
67 #include <netgraph/netgraph.h>
68 #include <netgraph/ng_parse.h>
69 
70 MODULE_VERSION(netgraph, NG_ABI_VERSION);
71 
72 /* List of all active nodes */
73 static LIST_HEAD(, ng_node) ng_nodelist;
74 static struct mtx	ng_nodelist_mtx;
75 
76 /* Mutex to protect topology events. */
77 static struct mtx	ng_topo_mtx;
78 
79 #ifdef	NETGRAPH_DEBUG
80 static struct mtx	ngq_mtx;	/* protects the queue item list */
81 
82 static SLIST_HEAD(, ng_node) ng_allnodes;
83 static LIST_HEAD(, ng_node) ng_freenodes; /* in debug, we never free() them */
84 static SLIST_HEAD(, ng_hook) ng_allhooks;
85 static LIST_HEAD(, ng_hook) ng_freehooks; /* in debug, we never free() them */
86 
87 static void ng_dumpitems(void);
88 static void ng_dumpnodes(void);
89 static void ng_dumphooks(void);
90 
91 #endif	/* NETGRAPH_DEBUG */
92 /*
93  * DEAD versions of the structures.
94  * In order to avoid races, it is sometimes neccesary to point
95  * at SOMETHING even though theoretically, the current entity is
96  * INVALID. Use these to avoid these races.
97  */
98 struct ng_type ng_deadtype = {
99 	NG_ABI_VERSION,
100 	"dead",
101 	NULL,	/* modevent */
102 	NULL,	/* constructor */
103 	NULL,	/* rcvmsg */
104 	NULL,	/* shutdown */
105 	NULL,	/* newhook */
106 	NULL,	/* findhook */
107 	NULL,	/* connect */
108 	NULL,	/* rcvdata */
109 	NULL,	/* disconnect */
110 	NULL, 	/* cmdlist */
111 };
112 
113 struct ng_node ng_deadnode = {
114 	"dead",
115 	&ng_deadtype,
116 	NGF_INVALID,
117 	1,	/* refs */
118 	0,	/* numhooks */
119 	NULL,	/* private */
120 	0,	/* ID */
121 	LIST_HEAD_INITIALIZER(ng_deadnode.hooks),
122 	{},	/* all_nodes list entry */
123 	{},	/* id hashtable list entry */
124 	{},	/* workqueue entry */
125 	{	0,
126 		{}, /* should never use! (should hang) */
127 		NULL,
128 		&ng_deadnode.nd_input_queue.queue,
129 		&ng_deadnode
130 	},
131 #ifdef	NETGRAPH_DEBUG
132 	ND_MAGIC,
133 	__FILE__,
134 	__LINE__,
135 	{NULL}
136 #endif	/* NETGRAPH_DEBUG */
137 };
138 
139 struct ng_hook ng_deadhook = {
140 	"dead",
141 	NULL,		/* private */
142 	HK_INVALID | HK_DEAD,
143 	1,		/* refs always >= 1 */
144 	0,		/* undefined data link type */
145 	&ng_deadhook,	/* Peer is self */
146 	&ng_deadnode,	/* attached to deadnode */
147 	{},		/* hooks list */
148 	NULL,		/* override rcvmsg() */
149 	NULL,		/* override rcvdata() */
150 #ifdef	NETGRAPH_DEBUG
151 	HK_MAGIC,
152 	__FILE__,
153 	__LINE__,
154 	{NULL}
155 #endif	/* NETGRAPH_DEBUG */
156 };
157 
158 /*
159  * END DEAD STRUCTURES
160  */
161 /* List nodes with unallocated work */
162 static TAILQ_HEAD(, ng_node) ng_worklist = TAILQ_HEAD_INITIALIZER(ng_worklist);
163 static struct mtx	ng_worklist_mtx;   /* MUST LOCK NODE FIRST */
164 
165 /* List of installed types */
166 static LIST_HEAD(, ng_type) ng_typelist;
167 static struct mtx	ng_typelist_mtx;
168 
169 /* Hash related definitions */
170 /* XXX Don't need to initialise them because it's a LIST */
171 #define NG_ID_HASH_SIZE 32 /* most systems wont need even this many */
172 static LIST_HEAD(, ng_node) ng_ID_hash[NG_ID_HASH_SIZE];
173 static struct mtx	ng_idhash_mtx;
174 /* Method to find a node.. used twice so do it here */
175 #define NG_IDHASH_FN(ID) ((ID) % (NG_ID_HASH_SIZE))
176 #define NG_IDHASH_FIND(ID, node)					\
177 	do { 								\
178 		mtx_assert(&ng_idhash_mtx, MA_OWNED);			\
179 		LIST_FOREACH(node, &ng_ID_hash[NG_IDHASH_FN(ID)],	\
180 						nd_idnodes) {		\
181 			if (NG_NODE_IS_VALID(node)			\
182 			&& (NG_NODE_ID(node) == ID)) {			\
183 				break;					\
184 			}						\
185 		}							\
186 	} while (0)
187 
188 
189 /* Internal functions */
190 static int	ng_add_hook(node_p node, const char *name, hook_p * hookp);
191 static int	ng_generic_msg(node_p here, item_p item, hook_p lasthook);
192 static ng_ID_t	ng_decodeidname(const char *name);
193 static int	ngb_mod_event(module_t mod, int event, void *data);
194 static void	ng_worklist_remove(node_p node);
195 static void	ngintr(void);
196 static int	ng_apply_item(node_p node, item_p item, int rw);
197 static void	ng_flush_input_queue(struct ng_queue * ngq);
198 static void	ng_setisr(node_p node);
199 static node_p	ng_ID2noderef(ng_ID_t ID);
200 static int	ng_con_nodes(item_p item, node_p node, const char *name,
201 		    node_p node2, const char *name2);
202 static int	ng_con_part2(node_p node, item_p item, hook_p hook);
203 static int	ng_con_part3(node_p node, item_p item, hook_p hook);
204 static int	ng_mkpeer(node_p node, const char *name,
205 						const char *name2, char *type);
206 
207 /* Imported, these used to be externally visible, some may go back. */
208 void	ng_destroy_hook(hook_p hook);
209 node_p	ng_name2noderef(node_p node, const char *name);
210 int	ng_path2noderef(node_p here, const char *path,
211 	node_p *dest, hook_p *lasthook);
212 int	ng_make_node(const char *type, node_p *nodepp);
213 int	ng_path_parse(char *addr, char **node, char **path, char **hook);
214 void	ng_rmnode(node_p node, hook_p dummy1, void *dummy2, int dummy3);
215 void	ng_unname(node_p node);
216 
217 
218 /* Our own netgraph malloc type */
219 MALLOC_DEFINE(M_NETGRAPH, "netgraph", "netgraph structures and ctrl messages");
220 MALLOC_DEFINE(M_NETGRAPH_HOOK, "netgraph_hook", "netgraph hook structures");
221 MALLOC_DEFINE(M_NETGRAPH_NODE, "netgraph_node", "netgraph node structures");
222 MALLOC_DEFINE(M_NETGRAPH_ITEM, "netgraph_item", "netgraph item structures");
223 MALLOC_DEFINE(M_NETGRAPH_MSG, "netgraph_msg", "netgraph name storage");
224 
225 /* Should not be visible outside this file */
226 
227 #define _NG_ALLOC_HOOK(hook) \
228 	MALLOC(hook, hook_p, sizeof(*hook), M_NETGRAPH_HOOK, M_NOWAIT | M_ZERO)
229 #define _NG_ALLOC_NODE(node) \
230 	MALLOC(node, node_p, sizeof(*node), M_NETGRAPH_NODE, M_NOWAIT | M_ZERO)
231 
232 #define	NG_QUEUE_LOCK_INIT(n)			\
233 	mtx_init(&(n)->q_mtx, "ng_node", NULL, MTX_DEF)
234 #define	NG_QUEUE_LOCK(n)			\
235 	mtx_lock(&(n)->q_mtx)
236 #define	NG_QUEUE_UNLOCK(n)			\
237 	mtx_unlock(&(n)->q_mtx)
238 #define	NG_WORKLIST_LOCK_INIT()			\
239 	mtx_init(&ng_worklist_mtx, "ng_worklist", NULL, MTX_DEF)
240 #define	NG_WORKLIST_LOCK()			\
241 	mtx_lock(&ng_worklist_mtx)
242 #define	NG_WORKLIST_UNLOCK()			\
243 	mtx_unlock(&ng_worklist_mtx)
244 
245 #ifdef NETGRAPH_DEBUG /*----------------------------------------------*/
246 /*
247  * In debug mode:
248  * In an attempt to help track reference count screwups
249  * we do not free objects back to the malloc system, but keep them
250  * in a local cache where we can examine them and keep information safely
251  * after they have been freed.
252  * We use this scheme for nodes and hooks, and to some extent for items.
253  */
254 static __inline hook_p
255 ng_alloc_hook(void)
256 {
257 	hook_p hook;
258 	SLIST_ENTRY(ng_hook) temp;
259 	mtx_lock(&ng_nodelist_mtx);
260 	hook = LIST_FIRST(&ng_freehooks);
261 	if (hook) {
262 		LIST_REMOVE(hook, hk_hooks);
263 		bcopy(&hook->hk_all, &temp, sizeof(temp));
264 		bzero(hook, sizeof(struct ng_hook));
265 		bcopy(&temp, &hook->hk_all, sizeof(temp));
266 		mtx_unlock(&ng_nodelist_mtx);
267 		hook->hk_magic = HK_MAGIC;
268 	} else {
269 		mtx_unlock(&ng_nodelist_mtx);
270 		_NG_ALLOC_HOOK(hook);
271 		if (hook) {
272 			hook->hk_magic = HK_MAGIC;
273 			mtx_lock(&ng_nodelist_mtx);
274 			SLIST_INSERT_HEAD(&ng_allhooks, hook, hk_all);
275 			mtx_unlock(&ng_nodelist_mtx);
276 		}
277 	}
278 	return (hook);
279 }
280 
281 static __inline node_p
282 ng_alloc_node(void)
283 {
284 	node_p node;
285 	SLIST_ENTRY(ng_node) temp;
286 	mtx_lock(&ng_nodelist_mtx);
287 	node = LIST_FIRST(&ng_freenodes);
288 	if (node) {
289 		LIST_REMOVE(node, nd_nodes);
290 		bcopy(&node->nd_all, &temp, sizeof(temp));
291 		bzero(node, sizeof(struct ng_node));
292 		bcopy(&temp, &node->nd_all, sizeof(temp));
293 		mtx_unlock(&ng_nodelist_mtx);
294 		node->nd_magic = ND_MAGIC;
295 	} else {
296 		mtx_unlock(&ng_nodelist_mtx);
297 		_NG_ALLOC_NODE(node);
298 		if (node) {
299 			node->nd_magic = ND_MAGIC;
300 			mtx_lock(&ng_nodelist_mtx);
301 			SLIST_INSERT_HEAD(&ng_allnodes, node, nd_all);
302 			mtx_unlock(&ng_nodelist_mtx);
303 		}
304 	}
305 	return (node);
306 }
307 
308 #define NG_ALLOC_HOOK(hook) do { (hook) = ng_alloc_hook(); } while (0)
309 #define NG_ALLOC_NODE(node) do { (node) = ng_alloc_node(); } while (0)
310 
311 
312 #define NG_FREE_HOOK(hook)						\
313 	do {								\
314 		mtx_lock(&ng_nodelist_mtx);			\
315 		LIST_INSERT_HEAD(&ng_freehooks, hook, hk_hooks);	\
316 		hook->hk_magic = 0;					\
317 		mtx_unlock(&ng_nodelist_mtx);			\
318 	} while (0)
319 
320 #define NG_FREE_NODE(node)						\
321 	do {								\
322 		mtx_lock(&ng_nodelist_mtx);			\
323 		LIST_INSERT_HEAD(&ng_freenodes, node, nd_nodes);	\
324 		node->nd_magic = 0;					\
325 		mtx_unlock(&ng_nodelist_mtx);			\
326 	} while (0)
327 
328 #else /* NETGRAPH_DEBUG */ /*----------------------------------------------*/
329 
330 #define NG_ALLOC_HOOK(hook) _NG_ALLOC_HOOK(hook)
331 #define NG_ALLOC_NODE(node) _NG_ALLOC_NODE(node)
332 
333 #define NG_FREE_HOOK(hook) do { FREE((hook), M_NETGRAPH_HOOK); } while (0)
334 #define NG_FREE_NODE(node) do { FREE((node), M_NETGRAPH_NODE); } while (0)
335 
336 #endif /* NETGRAPH_DEBUG */ /*----------------------------------------------*/
337 
338 /* Set this to kdb_enter("X") to catch all errors as they occur */
339 #ifndef TRAP_ERROR
340 #define TRAP_ERROR()
341 #endif
342 
343 static	ng_ID_t nextID = 1;
344 
345 #ifdef INVARIANTS
346 #define CHECK_DATA_MBUF(m)	do {					\
347 		struct mbuf *n;						\
348 		int total;						\
349 									\
350 		M_ASSERTPKTHDR(m);					\
351 		for (total = 0, n = (m); n != NULL; n = n->m_next) {	\
352 			total += n->m_len;				\
353 			if (n->m_nextpkt != NULL)			\
354 				panic("%s: m_nextpkt", __func__);	\
355 		}							\
356 									\
357 		if ((m)->m_pkthdr.len != total) {			\
358 			panic("%s: %d != %d",				\
359 			    __func__, (m)->m_pkthdr.len, total);	\
360 		}							\
361 	} while (0)
362 #else
363 #define CHECK_DATA_MBUF(m)
364 #endif
365 
366 #define ERROUT(x)	do { error = (x); goto done; } while (0)
367 
368 /************************************************************************
369 	Parse type definitions for generic messages
370 ************************************************************************/
371 
372 /* Handy structure parse type defining macro */
373 #define DEFINE_PARSE_STRUCT_TYPE(lo, up, args)				\
374 static const struct ng_parse_struct_field				\
375 	ng_ ## lo ## _type_fields[] = NG_GENERIC_ ## up ## _INFO args;	\
376 static const struct ng_parse_type ng_generic_ ## lo ## _type = {	\
377 	&ng_parse_struct_type,						\
378 	&ng_ ## lo ## _type_fields					\
379 }
380 
381 DEFINE_PARSE_STRUCT_TYPE(mkpeer, MKPEER, ());
382 DEFINE_PARSE_STRUCT_TYPE(connect, CONNECT, ());
383 DEFINE_PARSE_STRUCT_TYPE(name, NAME, ());
384 DEFINE_PARSE_STRUCT_TYPE(rmhook, RMHOOK, ());
385 DEFINE_PARSE_STRUCT_TYPE(nodeinfo, NODEINFO, ());
386 DEFINE_PARSE_STRUCT_TYPE(typeinfo, TYPEINFO, ());
387 DEFINE_PARSE_STRUCT_TYPE(linkinfo, LINKINFO, (&ng_generic_nodeinfo_type));
388 
389 /* Get length of an array when the length is stored as a 32 bit
390    value immediately preceding the array -- as with struct namelist
391    and struct typelist. */
392 static int
393 ng_generic_list_getLength(const struct ng_parse_type *type,
394 	const u_char *start, const u_char *buf)
395 {
396 	return *((const u_int32_t *)(buf - 4));
397 }
398 
399 /* Get length of the array of struct linkinfo inside a struct hooklist */
400 static int
401 ng_generic_linkinfo_getLength(const struct ng_parse_type *type,
402 	const u_char *start, const u_char *buf)
403 {
404 	const struct hooklist *hl = (const struct hooklist *)start;
405 
406 	return hl->nodeinfo.hooks;
407 }
408 
409 /* Array type for a variable length array of struct namelist */
410 static const struct ng_parse_array_info ng_nodeinfoarray_type_info = {
411 	&ng_generic_nodeinfo_type,
412 	&ng_generic_list_getLength
413 };
414 static const struct ng_parse_type ng_generic_nodeinfoarray_type = {
415 	&ng_parse_array_type,
416 	&ng_nodeinfoarray_type_info
417 };
418 
419 /* Array type for a variable length array of struct typelist */
420 static const struct ng_parse_array_info ng_typeinfoarray_type_info = {
421 	&ng_generic_typeinfo_type,
422 	&ng_generic_list_getLength
423 };
424 static const struct ng_parse_type ng_generic_typeinfoarray_type = {
425 	&ng_parse_array_type,
426 	&ng_typeinfoarray_type_info
427 };
428 
429 /* Array type for array of struct linkinfo in struct hooklist */
430 static const struct ng_parse_array_info ng_generic_linkinfo_array_type_info = {
431 	&ng_generic_linkinfo_type,
432 	&ng_generic_linkinfo_getLength
433 };
434 static const struct ng_parse_type ng_generic_linkinfo_array_type = {
435 	&ng_parse_array_type,
436 	&ng_generic_linkinfo_array_type_info
437 };
438 
439 DEFINE_PARSE_STRUCT_TYPE(typelist, TYPELIST, (&ng_generic_nodeinfoarray_type));
440 DEFINE_PARSE_STRUCT_TYPE(hooklist, HOOKLIST,
441 	(&ng_generic_nodeinfo_type, &ng_generic_linkinfo_array_type));
442 DEFINE_PARSE_STRUCT_TYPE(listnodes, LISTNODES,
443 	(&ng_generic_nodeinfoarray_type));
444 
445 /* List of commands and how to convert arguments to/from ASCII */
446 static const struct ng_cmdlist ng_generic_cmds[] = {
447 	{
448 	  NGM_GENERIC_COOKIE,
449 	  NGM_SHUTDOWN,
450 	  "shutdown",
451 	  NULL,
452 	  NULL
453 	},
454 	{
455 	  NGM_GENERIC_COOKIE,
456 	  NGM_MKPEER,
457 	  "mkpeer",
458 	  &ng_generic_mkpeer_type,
459 	  NULL
460 	},
461 	{
462 	  NGM_GENERIC_COOKIE,
463 	  NGM_CONNECT,
464 	  "connect",
465 	  &ng_generic_connect_type,
466 	  NULL
467 	},
468 	{
469 	  NGM_GENERIC_COOKIE,
470 	  NGM_NAME,
471 	  "name",
472 	  &ng_generic_name_type,
473 	  NULL
474 	},
475 	{
476 	  NGM_GENERIC_COOKIE,
477 	  NGM_RMHOOK,
478 	  "rmhook",
479 	  &ng_generic_rmhook_type,
480 	  NULL
481 	},
482 	{
483 	  NGM_GENERIC_COOKIE,
484 	  NGM_NODEINFO,
485 	  "nodeinfo",
486 	  NULL,
487 	  &ng_generic_nodeinfo_type
488 	},
489 	{
490 	  NGM_GENERIC_COOKIE,
491 	  NGM_LISTHOOKS,
492 	  "listhooks",
493 	  NULL,
494 	  &ng_generic_hooklist_type
495 	},
496 	{
497 	  NGM_GENERIC_COOKIE,
498 	  NGM_LISTNAMES,
499 	  "listnames",
500 	  NULL,
501 	  &ng_generic_listnodes_type	/* same as NGM_LISTNODES */
502 	},
503 	{
504 	  NGM_GENERIC_COOKIE,
505 	  NGM_LISTNODES,
506 	  "listnodes",
507 	  NULL,
508 	  &ng_generic_listnodes_type
509 	},
510 	{
511 	  NGM_GENERIC_COOKIE,
512 	  NGM_LISTTYPES,
513 	  "listtypes",
514 	  NULL,
515 	  &ng_generic_typeinfo_type
516 	},
517 	{
518 	  NGM_GENERIC_COOKIE,
519 	  NGM_TEXT_CONFIG,
520 	  "textconfig",
521 	  NULL,
522 	  &ng_parse_string_type
523 	},
524 	{
525 	  NGM_GENERIC_COOKIE,
526 	  NGM_TEXT_STATUS,
527 	  "textstatus",
528 	  NULL,
529 	  &ng_parse_string_type
530 	},
531 	{
532 	  NGM_GENERIC_COOKIE,
533 	  NGM_ASCII2BINARY,
534 	  "ascii2binary",
535 	  &ng_parse_ng_mesg_type,
536 	  &ng_parse_ng_mesg_type
537 	},
538 	{
539 	  NGM_GENERIC_COOKIE,
540 	  NGM_BINARY2ASCII,
541 	  "binary2ascii",
542 	  &ng_parse_ng_mesg_type,
543 	  &ng_parse_ng_mesg_type
544 	},
545 	{ 0 }
546 };
547 
548 /************************************************************************
549 			Node routines
550 ************************************************************************/
551 
552 /*
553  * Instantiate a node of the requested type
554  */
555 int
556 ng_make_node(const char *typename, node_p *nodepp)
557 {
558 	struct ng_type *type;
559 	int	error;
560 
561 	/* Check that the type makes sense */
562 	if (typename == NULL) {
563 		TRAP_ERROR();
564 		return (EINVAL);
565 	}
566 
567 	/* Locate the node type. If we fail we return. Do not try to load
568 	 * module.
569 	 */
570 	if ((type = ng_findtype(typename)) == NULL)
571 		return (ENXIO);
572 
573 	/*
574 	 * If we have a constructor, then make the node and
575 	 * call the constructor to do type specific initialisation.
576 	 */
577 	if (type->constructor != NULL) {
578 		if ((error = ng_make_node_common(type, nodepp)) == 0) {
579 			if ((error = ((*type->constructor)(*nodepp)) != 0)) {
580 				NG_NODE_UNREF(*nodepp);
581 			}
582 		}
583 	} else {
584 		/*
585 		 * Node has no constructor. We cannot ask for one
586 		 * to be made. It must be brought into existence by
587 		 * some external agency. The external agency should
588 		 * call ng_make_node_common() directly to get the
589 		 * netgraph part initialised.
590 		 */
591 		TRAP_ERROR();
592 		error = EINVAL;
593 	}
594 	return (error);
595 }
596 
597 /*
598  * Generic node creation. Called by node initialisation for externally
599  * instantiated nodes (e.g. hardware, sockets, etc ).
600  * The returned node has a reference count of 1.
601  */
602 int
603 ng_make_node_common(struct ng_type *type, node_p *nodepp)
604 {
605 	node_p node;
606 
607 	/* Require the node type to have been already installed */
608 	if (ng_findtype(type->name) == NULL) {
609 		TRAP_ERROR();
610 		return (EINVAL);
611 	}
612 
613 	/* Make a node and try attach it to the type */
614 	NG_ALLOC_NODE(node);
615 	if (node == NULL) {
616 		TRAP_ERROR();
617 		return (ENOMEM);
618 	}
619 	node->nd_type = type;
620 	NG_NODE_REF(node);				/* note reference */
621 	type->refs++;
622 
623 	NG_QUEUE_LOCK_INIT(&node->nd_input_queue);
624 	node->nd_input_queue.queue = NULL;
625 	node->nd_input_queue.last = &node->nd_input_queue.queue;
626 	node->nd_input_queue.q_flags = 0;
627 	node->nd_input_queue.q_node = node;
628 
629 	/* Initialize hook list for new node */
630 	LIST_INIT(&node->nd_hooks);
631 
632 	/* Link us into the node linked list */
633 	mtx_lock(&ng_nodelist_mtx);
634 	LIST_INSERT_HEAD(&ng_nodelist, node, nd_nodes);
635 	mtx_unlock(&ng_nodelist_mtx);
636 
637 
638 	/* get an ID and put us in the hash chain */
639 	mtx_lock(&ng_idhash_mtx);
640 	for (;;) { /* wrap protection, even if silly */
641 		node_p node2 = NULL;
642 		node->nd_ID = nextID++; /* 137/second for 1 year before wrap */
643 
644 		/* Is there a problem with the new number? */
645 		NG_IDHASH_FIND(node->nd_ID, node2); /* already taken? */
646 		if ((node->nd_ID != 0) && (node2 == NULL)) {
647 			break;
648 		}
649 	}
650 	LIST_INSERT_HEAD(&ng_ID_hash[NG_IDHASH_FN(node->nd_ID)],
651 							node, nd_idnodes);
652 	mtx_unlock(&ng_idhash_mtx);
653 
654 	/* Done */
655 	*nodepp = node;
656 	return (0);
657 }
658 
659 /*
660  * Forceably start the shutdown process on a node. Either call
661  * its shutdown method, or do the default shutdown if there is
662  * no type-specific method.
663  *
664  * We can only be called from a shutdown message, so we know we have
665  * a writer lock, and therefore exclusive access. It also means
666  * that we should not be on the work queue, but we check anyhow.
667  *
668  * Persistent node types must have a type-specific method which
669  * allocates a new node in which case, this one is irretrievably going away,
670  * or cleans up anything it needs, and just makes the node valid again,
671  * in which case we allow the node to survive.
672  *
673  * XXX We need to think of how to tell a persistent node that we
674  * REALLY need to go away because the hardware has gone or we
675  * are rebooting.... etc.
676  */
677 void
678 ng_rmnode(node_p node, hook_p dummy1, void *dummy2, int dummy3)
679 {
680 	hook_p hook;
681 
682 	/* Check if it's already shutting down */
683 	if ((node->nd_flags & NGF_CLOSING) != 0)
684 		return;
685 
686 	if (node == &ng_deadnode) {
687 		printf ("shutdown called on deadnode\n");
688 		return;
689 	}
690 
691 	/* Add an extra reference so it doesn't go away during this */
692 	NG_NODE_REF(node);
693 
694 	/*
695 	 * Mark it invalid so any newcomers know not to try use it
696 	 * Also add our own mark so we can't recurse
697 	 * note that NGF_INVALID does not do this as it's also set during
698 	 * creation
699 	 */
700 	node->nd_flags |= NGF_INVALID|NGF_CLOSING;
701 
702 	/* If node has its pre-shutdown method, then call it first*/
703 	if (node->nd_type && node->nd_type->close)
704 		(*node->nd_type->close)(node);
705 
706 	/* Notify all remaining connected nodes to disconnect */
707 	while ((hook = LIST_FIRST(&node->nd_hooks)) != NULL)
708 		ng_destroy_hook(hook);
709 
710 	/*
711 	 * Drain the input queue forceably.
712 	 * it has no hooks so what's it going to do, bleed on someone?
713 	 * Theoretically we came here from a queue entry that was added
714 	 * Just before the queue was closed, so it should be empty anyway.
715 	 * Also removes us from worklist if needed.
716 	 */
717 	ng_flush_input_queue(&node->nd_input_queue);
718 
719 	/* Ask the type if it has anything to do in this case */
720 	if (node->nd_type && node->nd_type->shutdown) {
721 		(*node->nd_type->shutdown)(node);
722 		if (NG_NODE_IS_VALID(node)) {
723 			/*
724 			 * Well, blow me down if the node code hasn't declared
725 			 * that it doesn't want to die.
726 			 * Presumably it is a persistant node.
727 			 * If we REALLY want it to go away,
728 			 *  e.g. hardware going away,
729 			 * Our caller should set NGF_REALLY_DIE in nd_flags.
730 			 */
731 			node->nd_flags &= ~(NGF_INVALID|NGF_CLOSING);
732 			NG_NODE_UNREF(node); /* Assume they still have theirs */
733 			return;
734 		}
735 	} else {				/* do the default thing */
736 		NG_NODE_UNREF(node);
737 	}
738 
739 	ng_unname(node); /* basically a NOP these days */
740 
741 	/*
742 	 * Remove extra reference, possibly the last
743 	 * Possible other holders of references may include
744 	 * timeout callouts, but theoretically the node's supposed to
745 	 * have cancelled them. Possibly hardware dependencies may
746 	 * force a driver to 'linger' with a reference.
747 	 */
748 	NG_NODE_UNREF(node);
749 }
750 
751 /*
752  * Remove a reference to the node, possibly the last.
753  * deadnode always acts as it it were the last.
754  */
755 int
756 ng_unref_node(node_p node)
757 {
758 	int v;
759 
760 	if (node == &ng_deadnode) {
761 		return (0);
762 	}
763 
764 	do {
765 		v = node->nd_refs - 1;
766 	} while (! atomic_cmpset_int(&node->nd_refs, v + 1, v));
767 
768 	if (v == 0) { /* we were the last */
769 
770 		mtx_lock(&ng_nodelist_mtx);
771 		node->nd_type->refs--; /* XXX maybe should get types lock? */
772 		LIST_REMOVE(node, nd_nodes);
773 		mtx_unlock(&ng_nodelist_mtx);
774 
775 		mtx_lock(&ng_idhash_mtx);
776 		LIST_REMOVE(node, nd_idnodes);
777 		mtx_unlock(&ng_idhash_mtx);
778 
779 		mtx_destroy(&node->nd_input_queue.q_mtx);
780 		NG_FREE_NODE(node);
781 	}
782 	return (v);
783 }
784 
785 /************************************************************************
786 			Node ID handling
787 ************************************************************************/
788 static node_p
789 ng_ID2noderef(ng_ID_t ID)
790 {
791 	node_p node;
792 	mtx_lock(&ng_idhash_mtx);
793 	NG_IDHASH_FIND(ID, node);
794 	if(node)
795 		NG_NODE_REF(node);
796 	mtx_unlock(&ng_idhash_mtx);
797 	return(node);
798 }
799 
800 ng_ID_t
801 ng_node2ID(node_p node)
802 {
803 	return (node ? NG_NODE_ID(node) : 0);
804 }
805 
806 /************************************************************************
807 			Node name handling
808 ************************************************************************/
809 
810 /*
811  * Assign a node a name. Once assigned, the name cannot be changed.
812  */
813 int
814 ng_name_node(node_p node, const char *name)
815 {
816 	int i;
817 	node_p node2;
818 
819 	/* Check the name is valid */
820 	for (i = 0; i < NG_NODESIZ; i++) {
821 		if (name[i] == '\0' || name[i] == '.' || name[i] == ':')
822 			break;
823 	}
824 	if (i == 0 || name[i] != '\0') {
825 		TRAP_ERROR();
826 		return (EINVAL);
827 	}
828 	if (ng_decodeidname(name) != 0) { /* valid IDs not allowed here */
829 		TRAP_ERROR();
830 		return (EINVAL);
831 	}
832 
833 	/* Check the name isn't already being used */
834 	if ((node2 = ng_name2noderef(node, name)) != NULL) {
835 		NG_NODE_UNREF(node2);
836 		TRAP_ERROR();
837 		return (EADDRINUSE);
838 	}
839 
840 	/* copy it */
841 	strlcpy(NG_NODE_NAME(node), name, NG_NODESIZ);
842 
843 	return (0);
844 }
845 
846 /*
847  * Find a node by absolute name. The name should NOT end with ':'
848  * The name "." means "this node" and "[xxx]" means "the node
849  * with ID (ie, at address) xxx".
850  *
851  * Returns the node if found, else NULL.
852  * Eventually should add something faster than a sequential search.
853  * Note it acquires a reference on the node so you can be sure it's still
854  * there.
855  */
856 node_p
857 ng_name2noderef(node_p here, const char *name)
858 {
859 	node_p node;
860 	ng_ID_t temp;
861 
862 	/* "." means "this node" */
863 	if (strcmp(name, ".") == 0) {
864 		NG_NODE_REF(here);
865 		return(here);
866 	}
867 
868 	/* Check for name-by-ID */
869 	if ((temp = ng_decodeidname(name)) != 0) {
870 		return (ng_ID2noderef(temp));
871 	}
872 
873 	/* Find node by name */
874 	mtx_lock(&ng_nodelist_mtx);
875 	LIST_FOREACH(node, &ng_nodelist, nd_nodes) {
876 		if (NG_NODE_IS_VALID(node)
877 		&& NG_NODE_HAS_NAME(node)
878 		&& (strcmp(NG_NODE_NAME(node), name) == 0)) {
879 			break;
880 		}
881 	}
882 	if (node)
883 		NG_NODE_REF(node);
884 	mtx_unlock(&ng_nodelist_mtx);
885 	return (node);
886 }
887 
888 /*
889  * Decode an ID name, eg. "[f03034de]". Returns 0 if the
890  * string is not valid, otherwise returns the value.
891  */
892 static ng_ID_t
893 ng_decodeidname(const char *name)
894 {
895 	const int len = strlen(name);
896 	char *eptr;
897 	u_long val;
898 
899 	/* Check for proper length, brackets, no leading junk */
900 	if ((len < 3)
901 	|| (name[0] != '[')
902 	|| (name[len - 1] != ']')
903 	|| (!isxdigit(name[1]))) {
904 		return ((ng_ID_t)0);
905 	}
906 
907 	/* Decode number */
908 	val = strtoul(name + 1, &eptr, 16);
909 	if ((eptr - name != len - 1)
910 	|| (val == ULONG_MAX)
911 	|| (val == 0)) {
912 		return ((ng_ID_t)0);
913 	}
914 	return (ng_ID_t)val;
915 }
916 
917 /*
918  * Remove a name from a node. This should only be called
919  * when shutting down and removing the node.
920  * IF we allow name changing this may be more resurrected.
921  */
922 void
923 ng_unname(node_p node)
924 {
925 }
926 
927 /************************************************************************
928 			Hook routines
929  Names are not optional. Hooks are always connected, except for a
930  brief moment within these routines. On invalidation or during creation
931  they are connected to the 'dead' hook.
932 ************************************************************************/
933 
934 /*
935  * Remove a hook reference
936  */
937 void
938 ng_unref_hook(hook_p hook)
939 {
940 	int v;
941 
942 	if (hook == &ng_deadhook) {
943 		return;
944 	}
945 	do {
946 		v = hook->hk_refs;
947 	} while (! atomic_cmpset_int(&hook->hk_refs, v, v - 1));
948 
949 	if (v == 1) { /* we were the last */
950 		if (_NG_HOOK_NODE(hook)) { /* it'll probably be ng_deadnode */
951 			_NG_NODE_UNREF((_NG_HOOK_NODE(hook)));
952 			hook->hk_node = NULL;
953 		}
954 		NG_FREE_HOOK(hook);
955 	}
956 }
957 
958 /*
959  * Add an unconnected hook to a node. Only used internally.
960  * Assumes node is locked. (XXX not yet true )
961  */
962 static int
963 ng_add_hook(node_p node, const char *name, hook_p *hookp)
964 {
965 	hook_p hook;
966 	int error = 0;
967 
968 	/* Check that the given name is good */
969 	if (name == NULL) {
970 		TRAP_ERROR();
971 		return (EINVAL);
972 	}
973 	if (ng_findhook(node, name) != NULL) {
974 		TRAP_ERROR();
975 		return (EEXIST);
976 	}
977 
978 	/* Allocate the hook and link it up */
979 	NG_ALLOC_HOOK(hook);
980 	if (hook == NULL) {
981 		TRAP_ERROR();
982 		return (ENOMEM);
983 	}
984 	hook->hk_refs = 1;		/* add a reference for us to return */
985 	hook->hk_flags = HK_INVALID;
986 	hook->hk_peer = &ng_deadhook;	/* start off this way */
987 	hook->hk_node = node;
988 	NG_NODE_REF(node);		/* each hook counts as a reference */
989 
990 	/* Set hook name */
991 	strlcpy(NG_HOOK_NAME(hook), name, NG_HOOKSIZ);
992 
993 	/*
994 	 * Check if the node type code has something to say about it
995 	 * If it fails, the unref of the hook will also unref the node.
996 	 */
997 	if (node->nd_type->newhook != NULL) {
998 		if ((error = (*node->nd_type->newhook)(node, hook, name))) {
999 			NG_HOOK_UNREF(hook);	/* this frees the hook */
1000 			return (error);
1001 		}
1002 	}
1003 	/*
1004 	 * The 'type' agrees so far, so go ahead and link it in.
1005 	 * We'll ask again later when we actually connect the hooks.
1006 	 */
1007 	LIST_INSERT_HEAD(&node->nd_hooks, hook, hk_hooks);
1008 	node->nd_numhooks++;
1009 	NG_HOOK_REF(hook);	/* one for the node */
1010 
1011 	if (hookp)
1012 		*hookp = hook;
1013 	return (0);
1014 }
1015 
1016 /*
1017  * Find a hook
1018  *
1019  * Node types may supply their own optimized routines for finding
1020  * hooks.  If none is supplied, we just do a linear search.
1021  * XXX Possibly we should add a reference to the hook?
1022  */
1023 hook_p
1024 ng_findhook(node_p node, const char *name)
1025 {
1026 	hook_p hook;
1027 
1028 	if (node->nd_type->findhook != NULL)
1029 		return (*node->nd_type->findhook)(node, name);
1030 	LIST_FOREACH(hook, &node->nd_hooks, hk_hooks) {
1031 		if (NG_HOOK_IS_VALID(hook)
1032 		&& (strcmp(NG_HOOK_NAME(hook), name) == 0))
1033 			return (hook);
1034 	}
1035 	return (NULL);
1036 }
1037 
1038 /*
1039  * Destroy a hook
1040  *
1041  * As hooks are always attached, this really destroys two hooks.
1042  * The one given, and the one attached to it. Disconnect the hooks
1043  * from each other first. We reconnect the peer hook to the 'dead'
1044  * hook so that it can still exist after we depart. We then
1045  * send the peer its own destroy message. This ensures that we only
1046  * interact with the peer's structures when it is locked processing that
1047  * message. We hold a reference to the peer hook so we are guaranteed that
1048  * the peer hook and node are still going to exist until
1049  * we are finished there as the hook holds a ref on the node.
1050  * We run this same code again on the peer hook, but that time it is already
1051  * attached to the 'dead' hook.
1052  *
1053  * This routine is called at all stages of hook creation
1054  * on error detection and must be able to handle any such stage.
1055  */
1056 void
1057 ng_destroy_hook(hook_p hook)
1058 {
1059 	hook_p peer;
1060 	node_p node;
1061 
1062 	if (hook == &ng_deadhook) {	/* better safe than sorry */
1063 		printf("ng_destroy_hook called on deadhook\n");
1064 		return;
1065 	}
1066 
1067 	/*
1068 	 * Protect divorce process with mutex, to avoid races on
1069 	 * simultaneous disconnect.
1070 	 */
1071 	mtx_lock(&ng_topo_mtx);
1072 
1073 	hook->hk_flags |= HK_INVALID;
1074 
1075 	peer = NG_HOOK_PEER(hook);
1076 	node = NG_HOOK_NODE(hook);
1077 
1078 	if (peer && (peer != &ng_deadhook)) {
1079 		/*
1080 		 * Set the peer to point to ng_deadhook
1081 		 * from this moment on we are effectively independent it.
1082 		 * send it an rmhook message of it's own.
1083 		 */
1084 		peer->hk_peer = &ng_deadhook;	/* They no longer know us */
1085 		hook->hk_peer = &ng_deadhook;	/* Nor us, them */
1086 		if (NG_HOOK_NODE(peer) == &ng_deadnode) {
1087 			/*
1088 			 * If it's already divorced from a node,
1089 			 * just free it.
1090 			 */
1091 			mtx_unlock(&ng_topo_mtx);
1092 		} else {
1093 			mtx_unlock(&ng_topo_mtx);
1094 			ng_rmhook_self(peer); 	/* Send it a surprise */
1095 		}
1096 		NG_HOOK_UNREF(peer);		/* account for peer link */
1097 		NG_HOOK_UNREF(hook);		/* account for peer link */
1098 	} else
1099 		mtx_unlock(&ng_topo_mtx);
1100 
1101 	mtx_assert(&ng_topo_mtx, MA_NOTOWNED);
1102 
1103 	/*
1104 	 * Remove the hook from the node's list to avoid possible recursion
1105 	 * in case the disconnection results in node shutdown.
1106 	 */
1107 	if (node == &ng_deadnode) { /* happens if called from ng_con_nodes() */
1108 		return;
1109 	}
1110 	LIST_REMOVE(hook, hk_hooks);
1111 	node->nd_numhooks--;
1112 	if (node->nd_type->disconnect) {
1113 		/*
1114 		 * The type handler may elect to destroy the node so don't
1115 		 * trust its existence after this point. (except
1116 		 * that we still hold a reference on it. (which we
1117 		 * inherrited from the hook we are destroying)
1118 		 */
1119 		(*node->nd_type->disconnect) (hook);
1120 	}
1121 
1122 	/*
1123 	 * Note that because we will point to ng_deadnode, the original node
1124 	 * is not decremented automatically so we do that manually.
1125 	 */
1126 	_NG_HOOK_NODE(hook) = &ng_deadnode;
1127 	NG_NODE_UNREF(node);	/* We no longer point to it so adjust count */
1128 	NG_HOOK_UNREF(hook);	/* Account for linkage (in list) to node */
1129 }
1130 
1131 /*
1132  * Take two hooks on a node and merge the connection so that the given node
1133  * is effectively bypassed.
1134  */
1135 int
1136 ng_bypass(hook_p hook1, hook_p hook2)
1137 {
1138 	if (hook1->hk_node != hook2->hk_node) {
1139 		TRAP_ERROR();
1140 		return (EINVAL);
1141 	}
1142 	hook1->hk_peer->hk_peer = hook2->hk_peer;
1143 	hook2->hk_peer->hk_peer = hook1->hk_peer;
1144 
1145 	hook1->hk_peer = &ng_deadhook;
1146 	hook2->hk_peer = &ng_deadhook;
1147 
1148 	NG_HOOK_UNREF(hook1);
1149 	NG_HOOK_UNREF(hook2);
1150 
1151 	/* XXX If we ever cache methods on hooks update them as well */
1152 	ng_destroy_hook(hook1);
1153 	ng_destroy_hook(hook2);
1154 	return (0);
1155 }
1156 
1157 /*
1158  * Install a new netgraph type
1159  */
1160 int
1161 ng_newtype(struct ng_type *tp)
1162 {
1163 	const size_t namelen = strlen(tp->name);
1164 
1165 	/* Check version and type name fields */
1166 	if ((tp->version != NG_ABI_VERSION)
1167 	|| (namelen == 0)
1168 	|| (namelen >= NG_TYPESIZ)) {
1169 		TRAP_ERROR();
1170 		if (tp->version != NG_ABI_VERSION) {
1171 			printf("Netgraph: Node type rejected. ABI mismatch. Suggest recompile\n");
1172 		}
1173 		return (EINVAL);
1174 	}
1175 
1176 	/* Check for name collision */
1177 	if (ng_findtype(tp->name) != NULL) {
1178 		TRAP_ERROR();
1179 		return (EEXIST);
1180 	}
1181 
1182 
1183 	/* Link in new type */
1184 	mtx_lock(&ng_typelist_mtx);
1185 	LIST_INSERT_HEAD(&ng_typelist, tp, types);
1186 	tp->refs = 1;	/* first ref is linked list */
1187 	mtx_unlock(&ng_typelist_mtx);
1188 	return (0);
1189 }
1190 
1191 /*
1192  * unlink a netgraph type
1193  * If no examples exist
1194  */
1195 int
1196 ng_rmtype(struct ng_type *tp)
1197 {
1198 	/* Check for name collision */
1199 	if (tp->refs != 1) {
1200 		TRAP_ERROR();
1201 		return (EBUSY);
1202 	}
1203 
1204 	/* Unlink type */
1205 	mtx_lock(&ng_typelist_mtx);
1206 	LIST_REMOVE(tp, types);
1207 	mtx_unlock(&ng_typelist_mtx);
1208 	return (0);
1209 }
1210 
1211 /*
1212  * Look for a type of the name given
1213  */
1214 struct ng_type *
1215 ng_findtype(const char *typename)
1216 {
1217 	struct ng_type *type;
1218 
1219 	mtx_lock(&ng_typelist_mtx);
1220 	LIST_FOREACH(type, &ng_typelist, types) {
1221 		if (strcmp(type->name, typename) == 0)
1222 			break;
1223 	}
1224 	mtx_unlock(&ng_typelist_mtx);
1225 	return (type);
1226 }
1227 
1228 /************************************************************************
1229 			Composite routines
1230 ************************************************************************/
1231 /*
1232  * Connect two nodes using the specified hooks, using queued functions.
1233  */
1234 static int
1235 ng_con_part3(node_p node, item_p item, hook_p hook)
1236 {
1237 	int	error = 0;
1238 
1239 	/*
1240 	 * When we run, we know that the node 'node' is locked for us.
1241 	 * Our caller has a reference on the hook.
1242 	 * Our caller has a reference on the node.
1243 	 * (In this case our caller is ng_apply_item() ).
1244 	 * The peer hook has a reference on the hook.
1245 	 * We are all set up except for the final call to the node, and
1246 	 * the clearing of the INVALID flag.
1247 	 */
1248 	if (NG_HOOK_NODE(hook) == &ng_deadnode) {
1249 		/*
1250 		 * The node must have been freed again since we last visited
1251 		 * here. ng_destry_hook() has this effect but nothing else does.
1252 		 * We should just release our references and
1253 		 * free anything we can think of.
1254 		 * Since we know it's been destroyed, and it's our caller
1255 		 * that holds the references, just return.
1256 		 */
1257 		ERROUT(ENOENT);
1258 	}
1259 	if (hook->hk_node->nd_type->connect) {
1260 		if ((error = (*hook->hk_node->nd_type->connect) (hook))) {
1261 			ng_destroy_hook(hook);	/* also zaps peer */
1262 			printf("failed in ng_con_part3()\n");
1263 			ERROUT(error);
1264 		}
1265 	}
1266 	/*
1267 	 *  XXX this is wrong for SMP. Possibly we need
1268 	 * to separate out 'create' and 'invalid' flags.
1269 	 * should only set flags on hooks we have locked under our node.
1270 	 */
1271 	hook->hk_flags &= ~HK_INVALID;
1272 done:
1273 	NG_FREE_ITEM(item);
1274 	return (error);
1275 }
1276 
1277 static int
1278 ng_con_part2(node_p node, item_p item, hook_p hook)
1279 {
1280 	hook_p	peer;
1281 	int	error = 0;
1282 
1283 	/*
1284 	 * When we run, we know that the node 'node' is locked for us.
1285 	 * Our caller has a reference on the hook.
1286 	 * Our caller has a reference on the node.
1287 	 * (In this case our caller is ng_apply_item() ).
1288 	 * The peer hook has a reference on the hook.
1289 	 * our node pointer points to the 'dead' node.
1290 	 * First check the hook name is unique.
1291 	 * Should not happen because we checked before queueing this.
1292 	 */
1293 	if (ng_findhook(node, NG_HOOK_NAME(hook)) != NULL) {
1294 		TRAP_ERROR();
1295 		ng_destroy_hook(hook); /* should destroy peer too */
1296 		printf("failed in ng_con_part2()\n");
1297 		ERROUT(EEXIST);
1298 	}
1299 	/*
1300 	 * Check if the node type code has something to say about it
1301 	 * If it fails, the unref of the hook will also unref the attached node,
1302 	 * however since that node is 'ng_deadnode' this will do nothing.
1303 	 * The peer hook will also be destroyed.
1304 	 */
1305 	if (node->nd_type->newhook != NULL) {
1306 		if ((error = (*node->nd_type->newhook)(node, hook,
1307 		    hook->hk_name))) {
1308 			ng_destroy_hook(hook); /* should destroy peer too */
1309 			printf("failed in ng_con_part2()\n");
1310 			ERROUT(error);
1311 		}
1312 	}
1313 
1314 	/*
1315 	 * The 'type' agrees so far, so go ahead and link it in.
1316 	 * We'll ask again later when we actually connect the hooks.
1317 	 */
1318 	hook->hk_node = node;		/* just overwrite ng_deadnode */
1319 	NG_NODE_REF(node);		/* each hook counts as a reference */
1320 	LIST_INSERT_HEAD(&node->nd_hooks, hook, hk_hooks);
1321 	node->nd_numhooks++;
1322 	NG_HOOK_REF(hook);	/* one for the node */
1323 
1324 	/*
1325 	 * We now have a symmetrical situation, where both hooks have been
1326 	 * linked to their nodes, the newhook methods have been called
1327 	 * And the references are all correct. The hooks are still marked
1328 	 * as invalid, as we have not called the 'connect' methods
1329 	 * yet.
1330 	 * We can call the local one immediately as we have the
1331 	 * node locked, but we need to queue the remote one.
1332 	 */
1333 	if (hook->hk_node->nd_type->connect) {
1334 		if ((error = (*hook->hk_node->nd_type->connect) (hook))) {
1335 			ng_destroy_hook(hook);	/* also zaps peer */
1336 			printf("failed in ng_con_part2(A)\n");
1337 			ERROUT(error);
1338 		}
1339 	}
1340 
1341 	/*
1342 	 * Acquire topo mutex to avoid race with ng_destroy_hook().
1343 	 */
1344 	mtx_lock(&ng_topo_mtx);
1345 	peer = hook->hk_peer;
1346 	if (peer == &ng_deadhook) {
1347 		mtx_unlock(&ng_topo_mtx);
1348 		printf("failed in ng_con_part2(B)\n");
1349 		ng_destroy_hook(hook);
1350 		ERROUT(ENOENT);
1351 	}
1352 	mtx_unlock(&ng_topo_mtx);
1353 
1354 	if ((error = ng_send_fn2(peer->hk_node, peer, item, &ng_con_part3,
1355 	    NULL, 0, NG_REUSE_ITEM))) {
1356 		printf("failed in ng_con_part2(C)\n");
1357 		ng_destroy_hook(hook);	/* also zaps peer */
1358 		return (error);		/* item was consumed. */
1359 	}
1360 	hook->hk_flags &= ~HK_INVALID; /* need both to be able to work */
1361 	return (0);			/* item was consumed. */
1362 done:
1363 	NG_FREE_ITEM(item);
1364 	return (error);
1365 }
1366 
1367 /*
1368  * Connect this node with another node. We assume that this node is
1369  * currently locked, as we are only called from an NGM_CONNECT message.
1370  */
1371 static int
1372 ng_con_nodes(item_p item, node_p node, const char *name,
1373     node_p node2, const char *name2)
1374 {
1375 	int	error;
1376 	hook_p	hook;
1377 	hook_p	hook2;
1378 
1379 	if (ng_findhook(node2, name2) != NULL) {
1380 		return(EEXIST);
1381 	}
1382 	if ((error = ng_add_hook(node, name, &hook)))  /* gives us a ref */
1383 		return (error);
1384 	/* Allocate the other hook and link it up */
1385 	NG_ALLOC_HOOK(hook2);
1386 	if (hook2 == NULL) {
1387 		TRAP_ERROR();
1388 		ng_destroy_hook(hook);	/* XXX check ref counts so far */
1389 		NG_HOOK_UNREF(hook);	/* including our ref */
1390 		return (ENOMEM);
1391 	}
1392 	hook2->hk_refs = 1;		/* start with a reference for us. */
1393 	hook2->hk_flags = HK_INVALID;
1394 	hook2->hk_peer = hook;		/* Link the two together */
1395 	hook->hk_peer = hook2;
1396 	NG_HOOK_REF(hook);		/* Add a ref for the peer to each*/
1397 	NG_HOOK_REF(hook2);
1398 	hook2->hk_node = &ng_deadnode;
1399 	strlcpy(NG_HOOK_NAME(hook2), name2, NG_HOOKSIZ);
1400 
1401 	/*
1402 	 * Queue the function above.
1403 	 * Procesing continues in that function in the lock context of
1404 	 * the other node.
1405 	 */
1406 	if ((error = ng_send_fn2(node2, hook2, item, &ng_con_part2, NULL, 0,
1407 	    NG_NOFLAGS))) {
1408 		printf("failed in ng_con_nodes(): %d\n", error);
1409 		ng_destroy_hook(hook);	/* also zaps peer */
1410 	}
1411 
1412 	NG_HOOK_UNREF(hook);		/* Let each hook go if it wants to */
1413 	NG_HOOK_UNREF(hook2);
1414 	return (error);
1415 }
1416 
1417 /*
1418  * Make a peer and connect.
1419  * We assume that the local node is locked.
1420  * The new node probably doesn't need a lock until
1421  * it has a hook, because it cannot really have any work until then,
1422  * but we should think about it a bit more.
1423  *
1424  * The problem may come if the other node also fires up
1425  * some hardware or a timer or some other source of activation,
1426  * also it may already get a command msg via it's ID.
1427  *
1428  * We could use the same method as ng_con_nodes() but we'd have
1429  * to add ability to remove the node when failing. (Not hard, just
1430  * make arg1 point to the node to remove).
1431  * Unless of course we just ignore failure to connect and leave
1432  * an unconnected node?
1433  */
1434 static int
1435 ng_mkpeer(node_p node, const char *name, const char *name2, char *type)
1436 {
1437 	node_p	node2;
1438 	hook_p	hook1, hook2;
1439 	int	error;
1440 
1441 	if ((error = ng_make_node(type, &node2))) {
1442 		return (error);
1443 	}
1444 
1445 	if ((error = ng_add_hook(node, name, &hook1))) { /* gives us a ref */
1446 		ng_rmnode(node2, NULL, NULL, 0);
1447 		return (error);
1448 	}
1449 
1450 	if ((error = ng_add_hook(node2, name2, &hook2))) {
1451 		ng_rmnode(node2, NULL, NULL, 0);
1452 		ng_destroy_hook(hook1);
1453 		NG_HOOK_UNREF(hook1);
1454 		return (error);
1455 	}
1456 
1457 	/*
1458 	 * Actually link the two hooks together.
1459 	 */
1460 	hook1->hk_peer = hook2;
1461 	hook2->hk_peer = hook1;
1462 
1463 	/* Each hook is referenced by the other */
1464 	NG_HOOK_REF(hook1);
1465 	NG_HOOK_REF(hook2);
1466 
1467 	/* Give each node the opportunity to veto the pending connection */
1468 	if (hook1->hk_node->nd_type->connect) {
1469 		error = (*hook1->hk_node->nd_type->connect) (hook1);
1470 	}
1471 
1472 	if ((error == 0) && hook2->hk_node->nd_type->connect) {
1473 		error = (*hook2->hk_node->nd_type->connect) (hook2);
1474 
1475 	}
1476 
1477 	/*
1478 	 * drop the references we were holding on the two hooks.
1479 	 */
1480 	if (error) {
1481 		ng_destroy_hook(hook2);	/* also zaps hook1 */
1482 		ng_rmnode(node2, NULL, NULL, 0);
1483 	} else {
1484 		/* As a last act, allow the hooks to be used */
1485 		hook1->hk_flags &= ~HK_INVALID;
1486 		hook2->hk_flags &= ~HK_INVALID;
1487 	}
1488 	NG_HOOK_UNREF(hook1);
1489 	NG_HOOK_UNREF(hook2);
1490 	return (error);
1491 }
1492 
1493 /************************************************************************
1494 		Utility routines to send self messages
1495 ************************************************************************/
1496 
1497 /* Shut this node down as soon as everyone is clear of it */
1498 /* Should add arg "immediately" to jump the queue */
1499 int
1500 ng_rmnode_self(node_p node)
1501 {
1502 	int		error;
1503 
1504 	if (node == &ng_deadnode)
1505 		return (0);
1506 	node->nd_flags |= NGF_INVALID;
1507 	if (node->nd_flags & NGF_CLOSING)
1508 		return (0);
1509 
1510 	error = ng_send_fn(node, NULL, &ng_rmnode, NULL, 0);
1511 	return (error);
1512 }
1513 
1514 static void
1515 ng_rmhook_part2(node_p node, hook_p hook, void *arg1, int arg2)
1516 {
1517 	ng_destroy_hook(hook);
1518 	return ;
1519 }
1520 
1521 int
1522 ng_rmhook_self(hook_p hook)
1523 {
1524 	int		error;
1525 	node_p node = NG_HOOK_NODE(hook);
1526 
1527 	if (node == &ng_deadnode)
1528 		return (0);
1529 
1530 	error = ng_send_fn(node, hook, &ng_rmhook_part2, NULL, 0);
1531 	return (error);
1532 }
1533 
1534 /***********************************************************************
1535  * Parse and verify a string of the form:  <NODE:><PATH>
1536  *
1537  * Such a string can refer to a specific node or a specific hook
1538  * on a specific node, depending on how you look at it. In the
1539  * latter case, the PATH component must not end in a dot.
1540  *
1541  * Both <NODE:> and <PATH> are optional. The <PATH> is a string
1542  * of hook names separated by dots. This breaks out the original
1543  * string, setting *nodep to "NODE" (or NULL if none) and *pathp
1544  * to "PATH" (or NULL if degenerate). Also, *hookp will point to
1545  * the final hook component of <PATH>, if any, otherwise NULL.
1546  *
1547  * This returns -1 if the path is malformed. The char ** are optional.
1548  ***********************************************************************/
1549 int
1550 ng_path_parse(char *addr, char **nodep, char **pathp, char **hookp)
1551 {
1552 	char	*node, *path, *hook;
1553 	int	k;
1554 
1555 	/*
1556 	 * Extract absolute NODE, if any
1557 	 */
1558 	for (path = addr; *path && *path != ':'; path++);
1559 	if (*path) {
1560 		node = addr;	/* Here's the NODE */
1561 		*path++ = '\0';	/* Here's the PATH */
1562 
1563 		/* Node name must not be empty */
1564 		if (!*node)
1565 			return -1;
1566 
1567 		/* A name of "." is OK; otherwise '.' not allowed */
1568 		if (strcmp(node, ".") != 0) {
1569 			for (k = 0; node[k]; k++)
1570 				if (node[k] == '.')
1571 					return -1;
1572 		}
1573 	} else {
1574 		node = NULL;	/* No absolute NODE */
1575 		path = addr;	/* Here's the PATH */
1576 	}
1577 
1578 	/* Snoop for illegal characters in PATH */
1579 	for (k = 0; path[k]; k++)
1580 		if (path[k] == ':')
1581 			return -1;
1582 
1583 	/* Check for no repeated dots in PATH */
1584 	for (k = 0; path[k]; k++)
1585 		if (path[k] == '.' && path[k + 1] == '.')
1586 			return -1;
1587 
1588 	/* Remove extra (degenerate) dots from beginning or end of PATH */
1589 	if (path[0] == '.')
1590 		path++;
1591 	if (*path && path[strlen(path) - 1] == '.')
1592 		path[strlen(path) - 1] = 0;
1593 
1594 	/* If PATH has a dot, then we're not talking about a hook */
1595 	if (*path) {
1596 		for (hook = path, k = 0; path[k]; k++)
1597 			if (path[k] == '.') {
1598 				hook = NULL;
1599 				break;
1600 			}
1601 	} else
1602 		path = hook = NULL;
1603 
1604 	/* Done */
1605 	if (nodep)
1606 		*nodep = node;
1607 	if (pathp)
1608 		*pathp = path;
1609 	if (hookp)
1610 		*hookp = hook;
1611 	return (0);
1612 }
1613 
1614 /*
1615  * Given a path, which may be absolute or relative, and a starting node,
1616  * return the destination node.
1617  */
1618 int
1619 ng_path2noderef(node_p here, const char *address,
1620 				node_p *destp, hook_p *lasthook)
1621 {
1622 	char    fullpath[NG_PATHSIZ];
1623 	char   *nodename, *path, pbuf[2];
1624 	node_p  node, oldnode;
1625 	char   *cp;
1626 	hook_p hook = NULL;
1627 
1628 	/* Initialize */
1629 	if (destp == NULL) {
1630 		TRAP_ERROR();
1631 		return EINVAL;
1632 	}
1633 	*destp = NULL;
1634 
1635 	/* Make a writable copy of address for ng_path_parse() */
1636 	strncpy(fullpath, address, sizeof(fullpath) - 1);
1637 	fullpath[sizeof(fullpath) - 1] = '\0';
1638 
1639 	/* Parse out node and sequence of hooks */
1640 	if (ng_path_parse(fullpath, &nodename, &path, NULL) < 0) {
1641 		TRAP_ERROR();
1642 		return EINVAL;
1643 	}
1644 	if (path == NULL) {
1645 		pbuf[0] = '.';	/* Needs to be writable */
1646 		pbuf[1] = '\0';
1647 		path = pbuf;
1648 	}
1649 
1650 	/*
1651 	 * For an absolute address, jump to the starting node.
1652 	 * Note that this holds a reference on the node for us.
1653 	 * Don't forget to drop the reference if we don't need it.
1654 	 */
1655 	if (nodename) {
1656 		node = ng_name2noderef(here, nodename);
1657 		if (node == NULL) {
1658 			TRAP_ERROR();
1659 			return (ENOENT);
1660 		}
1661 	} else {
1662 		if (here == NULL) {
1663 			TRAP_ERROR();
1664 			return (EINVAL);
1665 		}
1666 		node = here;
1667 		NG_NODE_REF(node);
1668 	}
1669 
1670 	/*
1671 	 * Now follow the sequence of hooks
1672 	 * XXX
1673 	 * We actually cannot guarantee that the sequence
1674 	 * is not being demolished as we crawl along it
1675 	 * without extra-ordinary locking etc.
1676 	 * So this is a bit dodgy to say the least.
1677 	 * We can probably hold up some things by holding
1678 	 * the nodelist mutex for the time of this
1679 	 * crawl if we wanted.. At least that way we wouldn't have to
1680 	 * worry about the nodes disappearing, but the hooks would still
1681 	 * be a problem.
1682 	 */
1683 	for (cp = path; node != NULL && *cp != '\0'; ) {
1684 		char *segment;
1685 
1686 		/*
1687 		 * Break out the next path segment. Replace the dot we just
1688 		 * found with a NUL; "cp" points to the next segment (or the
1689 		 * NUL at the end).
1690 		 */
1691 		for (segment = cp; *cp != '\0'; cp++) {
1692 			if (*cp == '.') {
1693 				*cp++ = '\0';
1694 				break;
1695 			}
1696 		}
1697 
1698 		/* Empty segment */
1699 		if (*segment == '\0')
1700 			continue;
1701 
1702 		/* We have a segment, so look for a hook by that name */
1703 		hook = ng_findhook(node, segment);
1704 
1705 		/* Can't get there from here... */
1706 		if (hook == NULL
1707 		    || NG_HOOK_PEER(hook) == NULL
1708 		    || NG_HOOK_NOT_VALID(hook)
1709 		    || NG_HOOK_NOT_VALID(NG_HOOK_PEER(hook))) {
1710 			TRAP_ERROR();
1711 			NG_NODE_UNREF(node);
1712 #if 0
1713 			printf("hooknotvalid %s %s %d %d %d %d ",
1714 					path,
1715 					segment,
1716 					hook == NULL,
1717 					NG_HOOK_PEER(hook) == NULL,
1718 					NG_HOOK_NOT_VALID(hook),
1719 					NG_HOOK_NOT_VALID(NG_HOOK_PEER(hook)));
1720 #endif
1721 			return (ENOENT);
1722 		}
1723 
1724 		/*
1725 		 * Hop on over to the next node
1726 		 * XXX
1727 		 * Big race conditions here as hooks and nodes go away
1728 		 * *** Idea.. store an ng_ID_t in each hook and use that
1729 		 * instead of the direct hook in this crawl?
1730 		 */
1731 		oldnode = node;
1732 		if ((node = NG_PEER_NODE(hook)))
1733 			NG_NODE_REF(node);	/* XXX RACE */
1734 		NG_NODE_UNREF(oldnode);	/* XXX another race */
1735 		if (NG_NODE_NOT_VALID(node)) {
1736 			NG_NODE_UNREF(node);	/* XXX more races */
1737 			node = NULL;
1738 		}
1739 	}
1740 
1741 	/* If node somehow missing, fail here (probably this is not needed) */
1742 	if (node == NULL) {
1743 		TRAP_ERROR();
1744 		return (ENXIO);
1745 	}
1746 
1747 	/* Done */
1748 	*destp = node;
1749 	if (lasthook != NULL)
1750 		*lasthook = (hook ? NG_HOOK_PEER(hook) : NULL);
1751 	return (0);
1752 }
1753 
1754 /***************************************************************\
1755 * Input queue handling.
1756 * All activities are submitted to the node via the input queue
1757 * which implements a multiple-reader/single-writer gate.
1758 * Items which cannot be handled immediately are queued.
1759 *
1760 * read-write queue locking inline functions			*
1761 \***************************************************************/
1762 
1763 static __inline item_p ng_dequeue(struct ng_queue * ngq, int *rw);
1764 static __inline item_p ng_acquire_read(struct ng_queue * ngq,
1765 					item_p  item);
1766 static __inline item_p ng_acquire_write(struct ng_queue * ngq,
1767 					item_p  item);
1768 static __inline void	ng_leave_read(struct ng_queue * ngq);
1769 static __inline void	ng_leave_write(struct ng_queue * ngq);
1770 static __inline void	ng_queue_rw(struct ng_queue * ngq,
1771 					item_p  item, int rw);
1772 
1773 /*
1774  * Definition of the bits fields in the ng_queue flag word.
1775  * Defined here rather than in netgraph.h because no-one should fiddle
1776  * with them.
1777  *
1778  * The ordering here may be important! don't shuffle these.
1779  */
1780 /*-
1781  Safety Barrier--------+ (adjustable to suit taste) (not used yet)
1782                        |
1783                        V
1784 +-------+-------+-------+-------+-------+-------+-------+-------+
1785   | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
1786   | |A|c|t|i|v|e| |R|e|a|d|e|r| |C|o|u|n|t| | | | | | | | | |P|A|
1787   | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |O|W|
1788 +-------+-------+-------+-------+-------+-------+-------+-------+
1789   \___________________________ ____________________________/ | |
1790                             V                                | |
1791                   [active reader count]                      | |
1792                                                              | |
1793             Operation Pending -------------------------------+ |
1794                                                                |
1795           Active Writer ---------------------------------------+
1796 
1797 
1798 */
1799 #define WRITER_ACTIVE	0x00000001
1800 #define OP_PENDING	0x00000002
1801 #define READER_INCREMENT 0x00000004
1802 #define READER_MASK	0xfffffffc	/* Not valid if WRITER_ACTIVE is set */
1803 #define SAFETY_BARRIER	0x00100000	/* 128K items queued should be enough */
1804 
1805 /* Defines of more elaborate states on the queue */
1806 /* Mask of bits a new read cares about */
1807 #define NGQ_RMASK	(WRITER_ACTIVE|OP_PENDING)
1808 
1809 /* Mask of bits a new write cares about */
1810 #define NGQ_WMASK	(NGQ_RMASK|READER_MASK)
1811 
1812 /* Test to decide if there is something on the queue. */
1813 #define QUEUE_ACTIVE(QP) ((QP)->q_flags & OP_PENDING)
1814 
1815 /* How to decide what the next queued item is. */
1816 #define HEAD_IS_READER(QP)  NGI_QUEUED_READER((QP)->queue)
1817 #define HEAD_IS_WRITER(QP)  NGI_QUEUED_WRITER((QP)->queue) /* notused */
1818 
1819 /* Read the status to decide if the next item on the queue can now run. */
1820 #define QUEUED_READER_CAN_PROCEED(QP)			\
1821 		(((QP)->q_flags & (NGQ_RMASK & ~OP_PENDING)) == 0)
1822 #define QUEUED_WRITER_CAN_PROCEED(QP)			\
1823 		(((QP)->q_flags & (NGQ_WMASK & ~OP_PENDING)) == 0)
1824 
1825 /* Is there a chance of getting ANY work off the queue? */
1826 #define NEXT_QUEUED_ITEM_CAN_PROCEED(QP)				\
1827 	(QUEUE_ACTIVE(QP) && 						\
1828 	((HEAD_IS_READER(QP)) ? QUEUED_READER_CAN_PROCEED(QP) :		\
1829 				QUEUED_WRITER_CAN_PROCEED(QP)))
1830 
1831 
1832 #define NGQRW_R 0
1833 #define NGQRW_W 1
1834 
1835 /*
1836  * Taking into account the current state of the queue and node, possibly take
1837  * the next entry off the queue and return it. Return NULL if there was
1838  * nothing we could return, either because there really was nothing there, or
1839  * because the node was in a state where it cannot yet process the next item
1840  * on the queue.
1841  *
1842  * This MUST MUST MUST be called with the mutex held.
1843  */
1844 static __inline item_p
1845 ng_dequeue(struct ng_queue *ngq, int *rw)
1846 {
1847 	item_p item;
1848 	u_int		add_arg;
1849 
1850 	mtx_assert(&ngq->q_mtx, MA_OWNED);
1851 	/*
1852 	 * If there is nothing queued, then just return.
1853 	 * No point in continuing.
1854 	 * XXXGL: assert this?
1855 	 */
1856 	if (!QUEUE_ACTIVE(ngq)) {
1857 		CTR4(KTR_NET, "%20s: node [%x] (%p) queue empty; "
1858 		    "queue flags 0x%lx", __func__,
1859 		    ngq->q_node->nd_ID, ngq->q_node, ngq->q_flags);
1860 		return (NULL);
1861 	}
1862 
1863 	/*
1864 	 * From here, we can assume there is a head item.
1865 	 * We need to find out what it is and if it can be dequeued, given
1866 	 * the current state of the node.
1867 	 */
1868 	if (HEAD_IS_READER(ngq)) {
1869 		if (!QUEUED_READER_CAN_PROCEED(ngq)) {
1870 			/*
1871 			 * It's a reader but we can't use it.
1872 			 * We are stalled so make sure we don't
1873 			 * get called again until something changes.
1874 			 */
1875 			ng_worklist_remove(ngq->q_node);
1876 			CTR4(KTR_NET, "%20s: node [%x] (%p) queued reader "
1877 			    "can't proceed; queue flags 0x%lx", __func__,
1878 			    ngq->q_node->nd_ID, ngq->q_node, ngq->q_flags);
1879 			return (NULL);
1880 		}
1881 		/*
1882 		 * Head of queue is a reader and we have no write active.
1883 		 * We don't care how many readers are already active.
1884 		 * Add the correct increment for the reader count.
1885 		 */
1886 		add_arg = READER_INCREMENT;
1887 		*rw = NGQRW_R;
1888 	} else if (QUEUED_WRITER_CAN_PROCEED(ngq)) {
1889 		/*
1890 		 * There is a pending write, no readers and no active writer.
1891 		 * This means we can go ahead with the pending writer. Note
1892 		 * the fact that we now have a writer, ready for when we take
1893 		 * it off the queue.
1894 		 *
1895 		 * We don't need to worry about a possible collision with the
1896 		 * fasttrack reader.
1897 		 *
1898 		 * The fasttrack thread may take a long time to discover that we
1899 		 * are running so we would have an inconsistent state in the
1900 		 * flags for a while. Since we ignore the reader count
1901 		 * entirely when the WRITER_ACTIVE flag is set, this should
1902 		 * not matter (in fact it is defined that way). If it tests
1903 		 * the flag before this operation, the OP_PENDING flag
1904 		 * will make it fail, and if it tests it later, the
1905 		 * WRITER_ACTIVE flag will do the same. If it is SO slow that
1906 		 * we have actually completed the operation, and neither flag
1907 		 * is set by the time that it tests the flags, then it is
1908 		 * actually ok for it to continue. If it completes and we've
1909 		 * finished and the read pending is set it still fails.
1910 		 *
1911 		 * So we can just ignore it,  as long as we can ensure that the
1912 		 * transition from WRITE_PENDING state to the WRITER_ACTIVE
1913 		 * state is atomic.
1914 		 *
1915 		 * After failing, first it will be held back by the mutex, then
1916 		 * when it can proceed, it will queue its request, then it
1917 		 * would arrive at this function. Usually it will have to
1918 		 * leave empty handed because the ACTIVE WRITER bit will be
1919 		 * set.
1920 		 *
1921 		 * Adjust the flags for the new active writer.
1922 		 */
1923 		add_arg = WRITER_ACTIVE;
1924 		*rw = NGQRW_W;
1925 		/*
1926 		 * We want to write "active writer, no readers " Now go make
1927 		 * it true. In fact there may be a number in the readers
1928 		 * count but we know it is not true and will be fixed soon.
1929 		 * We will fix the flags for the next pending entry in a
1930 		 * moment.
1931 		 */
1932 	} else {
1933 		/*
1934 		 * We can't dequeue anything.. return and say so. Probably we
1935 		 * have a write pending and the readers count is non zero. If
1936 		 * we got here because a reader hit us just at the wrong
1937 		 * moment with the fasttrack code, and put us in a strange
1938 		 * state, then it will be coming through in just a moment,
1939 		 * (just as soon as we release the mutex) and keep things
1940 		 * moving.
1941 		 * Make sure we remove ourselves from the work queue. It
1942 		 * would be a waste of effort to do all this again.
1943 		 */
1944 		ng_worklist_remove(ngq->q_node);
1945 		CTR4(KTR_NET, "%20s: node [%x] (%p) can't dequeue anything; "
1946 		    "queue flags 0x%lx", __func__,
1947 		    ngq->q_node->nd_ID, ngq->q_node, ngq->q_flags);
1948 		return (NULL);
1949 	}
1950 
1951 	/*
1952 	 * Now we dequeue the request (whatever it may be) and correct the
1953 	 * pending flags and the next and last pointers.
1954 	 */
1955 	item = ngq->queue;
1956 	ngq->queue = item->el_next;
1957 	CTR6(KTR_NET, "%20s: node [%x] (%p) dequeued item %p with flags 0x%lx; "
1958 	    "queue flags 0x%lx", __func__,
1959 	    ngq->q_node->nd_ID,ngq->q_node, item, item->el_flags, ngq->q_flags);
1960 	if (ngq->last == &(item->el_next)) {
1961 		/*
1962 		 * that was the last entry in the queue so set the 'last
1963 		 * pointer up correctly and make sure the pending flag is
1964 		 * clear.
1965 		 */
1966 		add_arg += -OP_PENDING;
1967 		ngq->last = &(ngq->queue);
1968 		/*
1969 		 * Whatever flag was set will be cleared and
1970 		 * the new acive field will be set by the add as well,
1971 		 * so we don't need to change add_arg.
1972 		 * But we know we don't need to be on the work list.
1973 		 */
1974 		atomic_add_long(&ngq->q_flags, add_arg);
1975 		ng_worklist_remove(ngq->q_node);
1976 	} else {
1977 		/*
1978 		 * Since there is still something on the queue
1979 		 * we don't need to change the PENDING flag.
1980 		 */
1981 		atomic_add_long(&ngq->q_flags, add_arg);
1982 		/*
1983 		 * If we see more doable work, make sure we are
1984 		 * on the work queue.
1985 		 */
1986 		if (NEXT_QUEUED_ITEM_CAN_PROCEED(ngq)) {
1987 			ng_setisr(ngq->q_node);
1988 		}
1989 	}
1990 	CTR6(KTR_NET, "%20s: node [%x] (%p) returning item %p as %s; "
1991 	    "queue flags 0x%lx", __func__,
1992 	    ngq->q_node->nd_ID, ngq->q_node, item, *rw ? "WRITER" : "READER" ,
1993 	    ngq->q_flags);
1994 	return (item);
1995 }
1996 
1997 /*
1998  * Queue a packet to be picked up by someone else.
1999  * We really don't care who, but we can't or don't want to hang around
2000  * to process it ourselves. We are probably an interrupt routine..
2001  * If the queue could be run, flag the netisr handler to start.
2002  */
2003 static __inline void
2004 ng_queue_rw(struct ng_queue * ngq, item_p  item, int rw)
2005 {
2006 	mtx_assert(&ngq->q_mtx, MA_OWNED);
2007 
2008 	if (rw == NGQRW_W)
2009 		NGI_SET_WRITER(item);
2010 	else
2011 		NGI_SET_READER(item);
2012 	item->el_next = NULL;	/* maybe not needed */
2013 	*ngq->last = item;
2014 	CTR5(KTR_NET, "%20s: node [%x] (%p) queued item %p as %s", __func__,
2015 	    ngq->q_node->nd_ID, ngq->q_node, item, rw ? "WRITER" : "READER" );
2016 	/*
2017 	 * If it was the first item in the queue then we need to
2018 	 * set the last pointer and the type flags.
2019 	 */
2020 	if (ngq->last == &(ngq->queue)) {
2021 		atomic_add_long(&ngq->q_flags, OP_PENDING);
2022 		CTR3(KTR_NET, "%20s: node [%x] (%p) set OP_PENDING", __func__,
2023 		    ngq->q_node->nd_ID, ngq->q_node);
2024 	}
2025 
2026 	ngq->last = &(item->el_next);
2027 	/*
2028 	 * We can take the worklist lock with the node locked
2029 	 * BUT NOT THE REVERSE!
2030 	 */
2031 	if (NEXT_QUEUED_ITEM_CAN_PROCEED(ngq))
2032 		ng_setisr(ngq->q_node);
2033 }
2034 
2035 
2036 /*
2037  * This function 'cheats' in that it first tries to 'grab' the use of the
2038  * node, without going through the mutex. We can do this becasue of the
2039  * semantics of the lock. The semantics include a clause that says that the
2040  * value of the readers count is invalid if the WRITER_ACTIVE flag is set. It
2041  * also says that the WRITER_ACTIVE flag cannot be set if the readers count
2042  * is not zero. Note that this talks about what is valid to SET the
2043  * WRITER_ACTIVE flag, because from the moment it is set, the value if the
2044  * reader count is immaterial, and not valid. The two 'pending' flags have a
2045  * similar effect, in that If they are orthogonal to the two active fields in
2046  * how they are set, but if either is set, the attempted 'grab' need to be
2047  * backed out because there is earlier work, and we maintain ordering in the
2048  * queue. The result of this is that the reader request can try obtain use of
2049  * the node with only a single atomic addition, and without any of the mutex
2050  * overhead. If this fails the operation degenerates to the same as for other
2051  * cases.
2052  *
2053  */
2054 static __inline item_p
2055 ng_acquire_read(struct ng_queue *ngq, item_p item)
2056 {
2057 	KASSERT(ngq != &ng_deadnode.nd_input_queue,
2058 	    ("%s: working on deadnode", __func__));
2059 
2060 	/* ######### Hack alert ######### */
2061 	atomic_add_long(&ngq->q_flags, READER_INCREMENT);
2062 	if ((ngq->q_flags & NGQ_RMASK) == 0) {
2063 		/* Successfully grabbed node */
2064 		CTR4(KTR_NET, "%20s: node [%x] (%p) fast acquired item %p",
2065 		    __func__, ngq->q_node->nd_ID, ngq->q_node, item);
2066 		return (item);
2067 	}
2068 	/* undo the damage if we didn't succeed */
2069 	atomic_subtract_long(&ngq->q_flags, READER_INCREMENT);
2070 
2071 	/* ######### End Hack alert ######### */
2072 	NG_QUEUE_LOCK(ngq);
2073 	/*
2074 	 * Try again. Another processor (or interrupt for that matter) may
2075 	 * have removed the last queued item that was stopping us from
2076 	 * running, between the previous test, and the moment that we took
2077 	 * the mutex. (Or maybe a writer completed.)
2078 	 * Even if another fast-track reader hits during this period
2079 	 * we don't care as multiple readers is OK.
2080 	 */
2081 	if ((ngq->q_flags & NGQ_RMASK) == 0) {
2082 		atomic_add_long(&ngq->q_flags, READER_INCREMENT);
2083 		NG_QUEUE_UNLOCK(ngq);
2084 		CTR4(KTR_NET, "%20s: node [%x] (%p) slow acquired item %p",
2085 		    __func__, ngq->q_node->nd_ID, ngq->q_node, item);
2086 		return (item);
2087 	}
2088 
2089 	/*
2090 	 * and queue the request for later.
2091 	 */
2092 	ng_queue_rw(ngq, item, NGQRW_R);
2093 	NG_QUEUE_UNLOCK(ngq);
2094 
2095 	return (NULL);
2096 }
2097 
2098 static __inline item_p
2099 ng_acquire_write(struct ng_queue *ngq, item_p item)
2100 {
2101 	KASSERT(ngq != &ng_deadnode.nd_input_queue,
2102 	    ("%s: working on deadnode", __func__));
2103 
2104 restart:
2105 	NG_QUEUE_LOCK(ngq);
2106 	/*
2107 	 * If there are no readers, no writer, and no pending packets, then
2108 	 * we can just go ahead. In all other situations we need to queue the
2109 	 * request
2110 	 */
2111 	if ((ngq->q_flags & NGQ_WMASK) == 0) {
2112 		/* collision could happen *HERE* */
2113 		atomic_add_long(&ngq->q_flags, WRITER_ACTIVE);
2114 		NG_QUEUE_UNLOCK(ngq);
2115 		if (ngq->q_flags & READER_MASK) {
2116 			/* Collision with fast-track reader */
2117 			atomic_subtract_long(&ngq->q_flags, WRITER_ACTIVE);
2118 			goto restart;
2119 		}
2120 		CTR4(KTR_NET, "%20s: node [%x] (%p) acquired item %p",
2121 		    __func__, ngq->q_node->nd_ID, ngq->q_node, item);
2122 		return (item);
2123 	}
2124 
2125 	/*
2126 	 * and queue the request for later.
2127 	 */
2128 	ng_queue_rw(ngq, item, NGQRW_W);
2129 	NG_QUEUE_UNLOCK(ngq);
2130 
2131 	return (NULL);
2132 }
2133 
2134 #if 0
2135 static __inline item_p
2136 ng_upgrade_write(struct ng_queue *ngq, item_p item)
2137 {
2138 	KASSERT(ngq != &ng_deadnode.nd_input_queue,
2139 	    ("%s: working on deadnode", __func__));
2140 
2141 	NGI_SET_WRITER(item);
2142 
2143 	mtx_lock_spin(&(ngq->q_mtx));
2144 
2145 	/*
2146 	 * There will never be no readers as we are there ourselves.
2147 	 * Set the WRITER_ACTIVE flags ASAP to block out fast track readers.
2148 	 * The caller we are running from will call ng_leave_read()
2149 	 * soon, so we must account for that. We must leave again with the
2150 	 * READER lock. If we find other readers, then
2151 	 * queue the request for later. However "later" may be rignt now
2152 	 * if there are no readers. We don't really care if there are queued
2153 	 * items as we will bypass them anyhow.
2154 	 */
2155 	atomic_add_long(&ngq->q_flags, WRITER_ACTIVE - READER_INCREMENT);
2156 	if (ngq->q_flags & (NGQ_WMASK & ~OP_PENDING) == WRITER_ACTIVE) {
2157 		mtx_unlock_spin(&(ngq->q_mtx));
2158 
2159 		/* It's just us, act on the item. */
2160 		/* will NOT drop writer lock when done */
2161 		ng_apply_item(node, item, 0);
2162 
2163 		/*
2164 		 * Having acted on the item, atomically
2165 		 * down grade back to READER and finish up
2166 	 	 */
2167 		atomic_add_long(&ngq->q_flags,
2168 		    READER_INCREMENT - WRITER_ACTIVE);
2169 
2170 		/* Our caller will call ng_leave_read() */
2171 		return;
2172 	}
2173 	/*
2174 	 * It's not just us active, so queue us AT THE HEAD.
2175 	 * "Why?" I hear you ask.
2176 	 * Put us at the head of the queue as we've already been
2177 	 * through it once. If there is nothing else waiting,
2178 	 * set the correct flags.
2179 	 */
2180 	if ((item->el_next = ngq->queue) == NULL) {
2181 		/*
2182 		 * Set up the "last" pointer.
2183 		 * We are the only (and thus last) item
2184 		 */
2185 		ngq->last = &(item->el_next);
2186 
2187 		/* We've gone from, 0 to 1 item in the queue */
2188 		atomic_add_long(&ngq->q_flags, OP_PENDING);
2189 
2190 		CTR3(KTR_NET, "%20s: node [%x] (%p) set OP_PENDING", __func__,
2191 		    ngq->q_node->nd_ID, ngq->q_node);
2192 	};
2193 	ngq->queue = item;
2194 	CTR5(KTR_NET, "%20s: node [%x] (%p) requeued item %p as WRITER",
2195 	    __func__, ngq->q_node->nd_ID, ngq->q_node, item );
2196 
2197 	/* Reverse what we did above. That downgrades us back to reader */
2198 	atomic_add_long(&ngq->q_flags, READER_INCREMENT - WRITER_ACTIVE);
2199 	if (NEXT_QUEUED_ITEM_CAN_PROCEED(ngq))
2200 		ng_setisr(ngq->q_node);
2201 	mtx_unlock_spin(&(ngq->q_mtx));
2202 
2203 	return;
2204 }
2205 
2206 #endif
2207 
2208 static __inline void
2209 ng_leave_read(struct ng_queue *ngq)
2210 {
2211 	atomic_subtract_long(&ngq->q_flags, READER_INCREMENT);
2212 }
2213 
2214 static __inline void
2215 ng_leave_write(struct ng_queue *ngq)
2216 {
2217 	atomic_subtract_long(&ngq->q_flags, WRITER_ACTIVE);
2218 }
2219 
2220 static void
2221 ng_flush_input_queue(struct ng_queue * ngq)
2222 {
2223 	item_p item;
2224 
2225 	NG_QUEUE_LOCK(ngq);
2226 	while (ngq->queue) {
2227 		item = ngq->queue;
2228 		ngq->queue = item->el_next;
2229 		if (ngq->last == &(item->el_next)) {
2230 			ngq->last = &(ngq->queue);
2231 			atomic_add_long(&ngq->q_flags, -OP_PENDING);
2232 		}
2233 		NG_QUEUE_UNLOCK(ngq);
2234 
2235 		/* If the item is supplying a callback, call it with an error */
2236 		if (item->apply != NULL &&
2237 		    refcount_release(&item->apply->refs)) {
2238 			(*item->apply->apply)(item->apply->context, ENOENT);
2239 		}
2240 		NG_FREE_ITEM(item);
2241 		NG_QUEUE_LOCK(ngq);
2242 	}
2243 	/*
2244 	 * Take us off the work queue if we are there.
2245 	 * We definately have no work to be done.
2246 	 */
2247 	ng_worklist_remove(ngq->q_node);
2248 	NG_QUEUE_UNLOCK(ngq);
2249 }
2250 
2251 /***********************************************************************
2252 * Externally visible method for sending or queueing messages or data.
2253 ***********************************************************************/
2254 
2255 /*
2256  * The module code should have filled out the item correctly by this stage:
2257  * Common:
2258  *    reference to destination node.
2259  *    Reference to destination rcv hook if relevant.
2260  *    apply pointer must be or NULL or reference valid struct ng_apply_info.
2261  * Data:
2262  *    pointer to mbuf
2263  * Control_Message:
2264  *    pointer to msg.
2265  *    ID of original sender node. (return address)
2266  * Function:
2267  *    Function pointer
2268  *    void * argument
2269  *    integer argument
2270  *
2271  * The nodes have several routines and macros to help with this task:
2272  */
2273 
2274 int
2275 ng_snd_item(item_p item, int flags)
2276 {
2277 	hook_p hook;
2278 	node_p node;
2279 	int queue, rw;
2280 	struct ng_queue *ngq;
2281 	int error = 0;
2282 
2283 	if (item == NULL) {
2284 		TRAP_ERROR();
2285 		return (EINVAL);	/* failed to get queue element */
2286 	}
2287 
2288 #ifdef	NETGRAPH_DEBUG
2289 	_ngi_check(item, __FILE__, __LINE__);
2290 #endif
2291 
2292 	if (item->apply)
2293 		refcount_acquire(&item->apply->refs);
2294 
2295 	hook = NGI_HOOK(item);
2296 	node = NGI_NODE(item);
2297 	ngq = &node->nd_input_queue;
2298 	if (node == NULL) {
2299 		TRAP_ERROR();
2300 		ERROUT(EINVAL);	/* No address */
2301 	}
2302 
2303 	queue = (flags & NG_QUEUE) ? 1 : 0;
2304 
2305 	switch(item->el_flags & NGQF_TYPE) {
2306 	case NGQF_DATA:
2307 		/*
2308 		 * DATA MESSAGE
2309 		 * Delivered to a node via a non-optional hook.
2310 		 * Both should be present in the item even though
2311 		 * the node is derivable from the hook.
2312 		 * References are held on both by the item.
2313 		 */
2314 
2315 		/* Protect nodes from sending NULL pointers
2316 		 * to each other
2317 		 */
2318 		if (NGI_M(item) == NULL)
2319 			ERROUT(EINVAL);
2320 
2321 		CHECK_DATA_MBUF(NGI_M(item));
2322 		if (hook == NULL) {
2323 			TRAP_ERROR();
2324 			ERROUT(EINVAL);
2325 		}
2326 		if ((NG_HOOK_NOT_VALID(hook))
2327 		|| (NG_NODE_NOT_VALID(NG_HOOK_NODE(hook)))) {
2328 			ERROUT(ENOTCONN);
2329 		}
2330 		if ((hook->hk_flags & HK_QUEUE)) {
2331 			queue = 1;
2332 		}
2333 		break;
2334 	case NGQF_MESG:
2335 		/*
2336 		 * CONTROL MESSAGE
2337 		 * Delivered to a node.
2338 		 * Hook is optional.
2339 		 * References are held by the item on the node and
2340 		 * the hook if it is present.
2341 		 */
2342 		if (hook && (hook->hk_flags & HK_QUEUE)) {
2343 			queue = 1;
2344 		}
2345 		break;
2346 	case NGQF_FN:
2347 	case NGQF_FN2:
2348 		break;
2349 	default:
2350 		TRAP_ERROR();
2351 		ERROUT(EINVAL);
2352 	}
2353 	switch(item->el_flags & NGQF_RW) {
2354 	case NGQF_READER:
2355 		rw = NGQRW_R;
2356 		break;
2357 	case NGQF_WRITER:
2358 		rw = NGQRW_W;
2359 		break;
2360 	default:
2361 		panic("%s: invalid item flags %lx", __func__, item->el_flags);
2362 	}
2363 
2364 	/*
2365 	 * If the node specifies single threading, force writer semantics.
2366 	 * Similarly, the node may say one hook always produces writers.
2367 	 * These are overrides.
2368 	 */
2369 	if ((node->nd_flags & NGF_FORCE_WRITER)
2370 	    || (hook && (hook->hk_flags & HK_FORCE_WRITER)))
2371 			rw = NGQRW_W;
2372 
2373 	if (queue) {
2374 		/* Put it on the queue for that node*/
2375 #ifdef	NETGRAPH_DEBUG
2376 		_ngi_check(item, __FILE__, __LINE__);
2377 #endif
2378 		NG_QUEUE_LOCK(ngq);
2379 		ng_queue_rw(ngq, item, rw);
2380 		NG_QUEUE_UNLOCK(ngq);
2381 
2382 		if (flags & NG_PROGRESS)
2383 			return (EINPROGRESS);
2384 		else
2385 			return (0);
2386 	}
2387 
2388 	/*
2389 	 * We already decided how we will be queueud or treated.
2390 	 * Try get the appropriate operating permission.
2391 	 */
2392  	if (rw == NGQRW_R)
2393 		item = ng_acquire_read(ngq, item);
2394 	else
2395 		item = ng_acquire_write(ngq, item);
2396 
2397 
2398 	if (item == NULL) {
2399 		if (flags & NG_PROGRESS)
2400 			return (EINPROGRESS);
2401 		else
2402 			return (0);
2403 	}
2404 
2405 #ifdef	NETGRAPH_DEBUG
2406 	_ngi_check(item, __FILE__, __LINE__);
2407 #endif
2408 
2409 	NGI_GET_NODE(item, node); /* zaps stored node */
2410 
2411 	error = ng_apply_item(node, item, rw); /* drops r/w lock when done */
2412 
2413 	/*
2414 	 * If the node goes away when we remove the reference,
2415 	 * whatever we just did caused it.. whatever we do, DO NOT
2416 	 * access the node again!
2417 	 */
2418 	if (NG_NODE_UNREF(node) == 0) {
2419 		return (error);
2420 	}
2421 
2422 	NG_QUEUE_LOCK(ngq);
2423 	if (NEXT_QUEUED_ITEM_CAN_PROCEED(ngq))
2424 		ng_setisr(ngq->q_node);
2425 	NG_QUEUE_UNLOCK(ngq);
2426 
2427 	return (error);
2428 
2429 done:
2430 	/* Apply callback. */
2431 	if (item->apply != NULL &&
2432 	    refcount_release(&item->apply->refs)) {
2433 		(*item->apply->apply)(item->apply->context, error);
2434 	}
2435 	NG_FREE_ITEM(item);
2436 	return (error);
2437 }
2438 
2439 /*
2440  * We have an item that was possibly queued somewhere.
2441  * It should contain all the information needed
2442  * to run it on the appropriate node/hook.
2443  * If there is apply pointer and we own the last reference, call apply().
2444  */
2445 static int
2446 ng_apply_item(node_p node, item_p item, int rw)
2447 {
2448 	hook_p  hook;
2449 	int	error = 0;
2450 	ng_rcvdata_t *rcvdata;
2451 	ng_rcvmsg_t *rcvmsg;
2452 	struct ng_apply_info *apply;
2453 
2454 	NGI_GET_HOOK(item, hook); /* clears stored hook */
2455 #ifdef	NETGRAPH_DEBUG
2456 	_ngi_check(item, __FILE__, __LINE__);
2457 #endif
2458 
2459 	apply = item->apply;
2460 
2461 	switch (item->el_flags & NGQF_TYPE) {
2462 	case NGQF_DATA:
2463 		/*
2464 		 * Check things are still ok as when we were queued.
2465 		 */
2466 		if ((hook == NULL)
2467 		|| NG_HOOK_NOT_VALID(hook)
2468 		|| NG_NODE_NOT_VALID(node) ) {
2469 			error = EIO;
2470 			NG_FREE_ITEM(item);
2471 			break;
2472 		}
2473 		/*
2474 		 * If no receive method, just silently drop it.
2475 		 * Give preference to the hook over-ride method
2476 		 */
2477 		if ((!(rcvdata = hook->hk_rcvdata))
2478 		&& (!(rcvdata = NG_HOOK_NODE(hook)->nd_type->rcvdata))) {
2479 			error = 0;
2480 			NG_FREE_ITEM(item);
2481 			break;
2482 		}
2483 		error = (*rcvdata)(hook, item);
2484 		break;
2485 	case NGQF_MESG:
2486 		if (hook) {
2487 			if (NG_HOOK_NOT_VALID(hook)) {
2488 				/*
2489 				 * The hook has been zapped then we can't
2490 				 * use it. Immediately drop its reference.
2491 				 * The message may not need it.
2492 				 */
2493 				NG_HOOK_UNREF(hook);
2494 				hook = NULL;
2495 			}
2496 		}
2497 		/*
2498 		 * Similarly, if the node is a zombie there is
2499 		 * nothing we can do with it, drop everything.
2500 		 */
2501 		if (NG_NODE_NOT_VALID(node)) {
2502 			TRAP_ERROR();
2503 			error = EINVAL;
2504 			NG_FREE_ITEM(item);
2505 		} else {
2506 			/*
2507 			 * Call the appropriate message handler for the object.
2508 			 * It is up to the message handler to free the message.
2509 			 * If it's a generic message, handle it generically,
2510 			 * otherwise call the type's message handler
2511 			 * (if it exists)
2512 			 * XXX (race). Remember that a queued message may
2513 			 * reference a node or hook that has just been
2514 			 * invalidated. It will exist as the queue code
2515 			 * is holding a reference, but..
2516 			 */
2517 
2518 			struct ng_mesg *msg = NGI_MSG(item);
2519 
2520 			/*
2521 			 * check if the generic handler owns it.
2522 			 */
2523 			if ((msg->header.typecookie == NGM_GENERIC_COOKIE)
2524 			&& ((msg->header.flags & NGF_RESP) == 0)) {
2525 				error = ng_generic_msg(node, item, hook);
2526 				break;
2527 			}
2528 			/*
2529 			 * Now see if there is a handler (hook or node specific)
2530 			 * in the target node. If none, silently discard.
2531 			 */
2532 			if (((!hook) || (!(rcvmsg = hook->hk_rcvmsg)))
2533 			&& (!(rcvmsg = node->nd_type->rcvmsg))) {
2534 				TRAP_ERROR();
2535 				error = 0;
2536 				NG_FREE_ITEM(item);
2537 				break;
2538 			}
2539 			error = (*rcvmsg)(node, item, hook);
2540 		}
2541 		break;
2542 	case NGQF_FN:
2543 	case NGQF_FN2:
2544 		/*
2545 		 *  We have to implicitly trust the hook,
2546 		 * as some of these are used for system purposes
2547 		 * where the hook is invalid. In the case of
2548 		 * the shutdown message we allow it to hit
2549 		 * even if the node is invalid.
2550 		 */
2551 		if ((NG_NODE_NOT_VALID(node))
2552 		&& (NGI_FN(item) != &ng_rmnode)) {
2553 			TRAP_ERROR();
2554 			error = EINVAL;
2555 			NG_FREE_ITEM(item);
2556 			break;
2557 		}
2558 		if ((item->el_flags & NGQF_TYPE) == NGQF_FN) {
2559 			(*NGI_FN(item))(node, hook, NGI_ARG1(item),
2560 			    NGI_ARG2(item));
2561 			NG_FREE_ITEM(item);
2562 		} else	/* it is NGQF_FN2 */
2563 			error = (*NGI_FN2(item))(node, item, hook);
2564 		break;
2565 	}
2566 	/*
2567 	 * We held references on some of the resources
2568 	 * that we took from the item. Now that we have
2569 	 * finished doing everything, drop those references.
2570 	 */
2571 	if (hook) {
2572 		NG_HOOK_UNREF(hook);
2573 	}
2574 
2575  	if (rw == NGQRW_R) {
2576 		ng_leave_read(&node->nd_input_queue);
2577 	} else {
2578 		ng_leave_write(&node->nd_input_queue);
2579 	}
2580 
2581 	/* Apply callback. */
2582 	if (apply != NULL &&
2583 	    refcount_release(&apply->refs)) {
2584 		(*apply->apply)(apply->context, error);
2585 	}
2586 
2587 	return (error);
2588 }
2589 
2590 /***********************************************************************
2591  * Implement the 'generic' control messages
2592  ***********************************************************************/
2593 static int
2594 ng_generic_msg(node_p here, item_p item, hook_p lasthook)
2595 {
2596 	int error = 0;
2597 	struct ng_mesg *msg;
2598 	struct ng_mesg *resp = NULL;
2599 
2600 	NGI_GET_MSG(item, msg);
2601 	if (msg->header.typecookie != NGM_GENERIC_COOKIE) {
2602 		TRAP_ERROR();
2603 		error = EINVAL;
2604 		goto out;
2605 	}
2606 	switch (msg->header.cmd) {
2607 	case NGM_SHUTDOWN:
2608 		ng_rmnode(here, NULL, NULL, 0);
2609 		break;
2610 	case NGM_MKPEER:
2611 	    {
2612 		struct ngm_mkpeer *const mkp = (struct ngm_mkpeer *) msg->data;
2613 
2614 		if (msg->header.arglen != sizeof(*mkp)) {
2615 			TRAP_ERROR();
2616 			error = EINVAL;
2617 			break;
2618 		}
2619 		mkp->type[sizeof(mkp->type) - 1] = '\0';
2620 		mkp->ourhook[sizeof(mkp->ourhook) - 1] = '\0';
2621 		mkp->peerhook[sizeof(mkp->peerhook) - 1] = '\0';
2622 		error = ng_mkpeer(here, mkp->ourhook, mkp->peerhook, mkp->type);
2623 		break;
2624 	    }
2625 	case NGM_CONNECT:
2626 	    {
2627 		struct ngm_connect *const con =
2628 			(struct ngm_connect *) msg->data;
2629 		node_p node2;
2630 
2631 		if (msg->header.arglen != sizeof(*con)) {
2632 			TRAP_ERROR();
2633 			error = EINVAL;
2634 			break;
2635 		}
2636 		con->path[sizeof(con->path) - 1] = '\0';
2637 		con->ourhook[sizeof(con->ourhook) - 1] = '\0';
2638 		con->peerhook[sizeof(con->peerhook) - 1] = '\0';
2639 		/* Don't forget we get a reference.. */
2640 		error = ng_path2noderef(here, con->path, &node2, NULL);
2641 		if (error)
2642 			break;
2643 		error = ng_con_nodes(item, here, con->ourhook,
2644 		    node2, con->peerhook);
2645 		NG_NODE_UNREF(node2);
2646 		break;
2647 	    }
2648 	case NGM_NAME:
2649 	    {
2650 		struct ngm_name *const nam = (struct ngm_name *) msg->data;
2651 
2652 		if (msg->header.arglen != sizeof(*nam)) {
2653 			TRAP_ERROR();
2654 			error = EINVAL;
2655 			break;
2656 		}
2657 		nam->name[sizeof(nam->name) - 1] = '\0';
2658 		error = ng_name_node(here, nam->name);
2659 		break;
2660 	    }
2661 	case NGM_RMHOOK:
2662 	    {
2663 		struct ngm_rmhook *const rmh = (struct ngm_rmhook *) msg->data;
2664 		hook_p hook;
2665 
2666 		if (msg->header.arglen != sizeof(*rmh)) {
2667 			TRAP_ERROR();
2668 			error = EINVAL;
2669 			break;
2670 		}
2671 		rmh->ourhook[sizeof(rmh->ourhook) - 1] = '\0';
2672 		if ((hook = ng_findhook(here, rmh->ourhook)) != NULL)
2673 			ng_destroy_hook(hook);
2674 		break;
2675 	    }
2676 	case NGM_NODEINFO:
2677 	    {
2678 		struct nodeinfo *ni;
2679 
2680 		NG_MKRESPONSE(resp, msg, sizeof(*ni), M_NOWAIT);
2681 		if (resp == NULL) {
2682 			error = ENOMEM;
2683 			break;
2684 		}
2685 
2686 		/* Fill in node info */
2687 		ni = (struct nodeinfo *) resp->data;
2688 		if (NG_NODE_HAS_NAME(here))
2689 			strcpy(ni->name, NG_NODE_NAME(here));
2690 		strcpy(ni->type, here->nd_type->name);
2691 		ni->id = ng_node2ID(here);
2692 		ni->hooks = here->nd_numhooks;
2693 		break;
2694 	    }
2695 	case NGM_LISTHOOKS:
2696 	    {
2697 		const int nhooks = here->nd_numhooks;
2698 		struct hooklist *hl;
2699 		struct nodeinfo *ni;
2700 		hook_p hook;
2701 
2702 		/* Get response struct */
2703 		NG_MKRESPONSE(resp, msg, sizeof(*hl)
2704 		    + (nhooks * sizeof(struct linkinfo)), M_NOWAIT);
2705 		if (resp == NULL) {
2706 			error = ENOMEM;
2707 			break;
2708 		}
2709 		hl = (struct hooklist *) resp->data;
2710 		ni = &hl->nodeinfo;
2711 
2712 		/* Fill in node info */
2713 		if (NG_NODE_HAS_NAME(here))
2714 			strcpy(ni->name, NG_NODE_NAME(here));
2715 		strcpy(ni->type, here->nd_type->name);
2716 		ni->id = ng_node2ID(here);
2717 
2718 		/* Cycle through the linked list of hooks */
2719 		ni->hooks = 0;
2720 		LIST_FOREACH(hook, &here->nd_hooks, hk_hooks) {
2721 			struct linkinfo *const link = &hl->link[ni->hooks];
2722 
2723 			if (ni->hooks >= nhooks) {
2724 				log(LOG_ERR, "%s: number of %s changed\n",
2725 				    __func__, "hooks");
2726 				break;
2727 			}
2728 			if (NG_HOOK_NOT_VALID(hook))
2729 				continue;
2730 			strcpy(link->ourhook, NG_HOOK_NAME(hook));
2731 			strcpy(link->peerhook, NG_PEER_HOOK_NAME(hook));
2732 			if (NG_PEER_NODE_NAME(hook)[0] != '\0')
2733 				strcpy(link->nodeinfo.name,
2734 				    NG_PEER_NODE_NAME(hook));
2735 			strcpy(link->nodeinfo.type,
2736 			   NG_PEER_NODE(hook)->nd_type->name);
2737 			link->nodeinfo.id = ng_node2ID(NG_PEER_NODE(hook));
2738 			link->nodeinfo.hooks = NG_PEER_NODE(hook)->nd_numhooks;
2739 			ni->hooks++;
2740 		}
2741 		break;
2742 	    }
2743 
2744 	case NGM_LISTNAMES:
2745 	case NGM_LISTNODES:
2746 	    {
2747 		const int unnamed = (msg->header.cmd == NGM_LISTNODES);
2748 		struct namelist *nl;
2749 		node_p node;
2750 		int num = 0;
2751 
2752 		mtx_lock(&ng_nodelist_mtx);
2753 		/* Count number of nodes */
2754 		LIST_FOREACH(node, &ng_nodelist, nd_nodes) {
2755 			if (NG_NODE_IS_VALID(node)
2756 			&& (unnamed || NG_NODE_HAS_NAME(node))) {
2757 				num++;
2758 			}
2759 		}
2760 		mtx_unlock(&ng_nodelist_mtx);
2761 
2762 		/* Get response struct */
2763 		NG_MKRESPONSE(resp, msg, sizeof(*nl)
2764 		    + (num * sizeof(struct nodeinfo)), M_NOWAIT);
2765 		if (resp == NULL) {
2766 			error = ENOMEM;
2767 			break;
2768 		}
2769 		nl = (struct namelist *) resp->data;
2770 
2771 		/* Cycle through the linked list of nodes */
2772 		nl->numnames = 0;
2773 		mtx_lock(&ng_nodelist_mtx);
2774 		LIST_FOREACH(node, &ng_nodelist, nd_nodes) {
2775 			struct nodeinfo *const np = &nl->nodeinfo[nl->numnames];
2776 
2777 			if (NG_NODE_NOT_VALID(node))
2778 				continue;
2779 			if (!unnamed && (! NG_NODE_HAS_NAME(node)))
2780 				continue;
2781 			if (nl->numnames >= num) {
2782 				log(LOG_ERR, "%s: number of %s changed\n",
2783 				    __func__, "nodes");
2784 				break;
2785 			}
2786 			if (NG_NODE_HAS_NAME(node))
2787 				strcpy(np->name, NG_NODE_NAME(node));
2788 			strcpy(np->type, node->nd_type->name);
2789 			np->id = ng_node2ID(node);
2790 			np->hooks = node->nd_numhooks;
2791 			nl->numnames++;
2792 		}
2793 		mtx_unlock(&ng_nodelist_mtx);
2794 		break;
2795 	    }
2796 
2797 	case NGM_LISTTYPES:
2798 	    {
2799 		struct typelist *tl;
2800 		struct ng_type *type;
2801 		int num = 0;
2802 
2803 		mtx_lock(&ng_typelist_mtx);
2804 		/* Count number of types */
2805 		LIST_FOREACH(type, &ng_typelist, types) {
2806 			num++;
2807 		}
2808 		mtx_unlock(&ng_typelist_mtx);
2809 
2810 		/* Get response struct */
2811 		NG_MKRESPONSE(resp, msg, sizeof(*tl)
2812 		    + (num * sizeof(struct typeinfo)), M_NOWAIT);
2813 		if (resp == NULL) {
2814 			error = ENOMEM;
2815 			break;
2816 		}
2817 		tl = (struct typelist *) resp->data;
2818 
2819 		/* Cycle through the linked list of types */
2820 		tl->numtypes = 0;
2821 		mtx_lock(&ng_typelist_mtx);
2822 		LIST_FOREACH(type, &ng_typelist, types) {
2823 			struct typeinfo *const tp = &tl->typeinfo[tl->numtypes];
2824 
2825 			if (tl->numtypes >= num) {
2826 				log(LOG_ERR, "%s: number of %s changed\n",
2827 				    __func__, "types");
2828 				break;
2829 			}
2830 			strcpy(tp->type_name, type->name);
2831 			tp->numnodes = type->refs - 1; /* don't count list */
2832 			tl->numtypes++;
2833 		}
2834 		mtx_unlock(&ng_typelist_mtx);
2835 		break;
2836 	    }
2837 
2838 	case NGM_BINARY2ASCII:
2839 	    {
2840 		int bufSize = 20 * 1024;	/* XXX hard coded constant */
2841 		const struct ng_parse_type *argstype;
2842 		const struct ng_cmdlist *c;
2843 		struct ng_mesg *binary, *ascii;
2844 
2845 		/* Data area must contain a valid netgraph message */
2846 		binary = (struct ng_mesg *)msg->data;
2847 		if (msg->header.arglen < sizeof(struct ng_mesg) ||
2848 		    (msg->header.arglen - sizeof(struct ng_mesg) <
2849 		    binary->header.arglen)) {
2850 			TRAP_ERROR();
2851 			error = EINVAL;
2852 			break;
2853 		}
2854 
2855 		/* Get a response message with lots of room */
2856 		NG_MKRESPONSE(resp, msg, sizeof(*ascii) + bufSize, M_NOWAIT);
2857 		if (resp == NULL) {
2858 			error = ENOMEM;
2859 			break;
2860 		}
2861 		ascii = (struct ng_mesg *)resp->data;
2862 
2863 		/* Copy binary message header to response message payload */
2864 		bcopy(binary, ascii, sizeof(*binary));
2865 
2866 		/* Find command by matching typecookie and command number */
2867 		for (c = here->nd_type->cmdlist;
2868 		    c != NULL && c->name != NULL; c++) {
2869 			if (binary->header.typecookie == c->cookie
2870 			    && binary->header.cmd == c->cmd)
2871 				break;
2872 		}
2873 		if (c == NULL || c->name == NULL) {
2874 			for (c = ng_generic_cmds; c->name != NULL; c++) {
2875 				if (binary->header.typecookie == c->cookie
2876 				    && binary->header.cmd == c->cmd)
2877 					break;
2878 			}
2879 			if (c->name == NULL) {
2880 				NG_FREE_MSG(resp);
2881 				error = ENOSYS;
2882 				break;
2883 			}
2884 		}
2885 
2886 		/* Convert command name to ASCII */
2887 		snprintf(ascii->header.cmdstr, sizeof(ascii->header.cmdstr),
2888 		    "%s", c->name);
2889 
2890 		/* Convert command arguments to ASCII */
2891 		argstype = (binary->header.flags & NGF_RESP) ?
2892 		    c->respType : c->mesgType;
2893 		if (argstype == NULL) {
2894 			*ascii->data = '\0';
2895 		} else {
2896 			if ((error = ng_unparse(argstype,
2897 			    (u_char *)binary->data,
2898 			    ascii->data, bufSize)) != 0) {
2899 				NG_FREE_MSG(resp);
2900 				break;
2901 			}
2902 		}
2903 
2904 		/* Return the result as struct ng_mesg plus ASCII string */
2905 		bufSize = strlen(ascii->data) + 1;
2906 		ascii->header.arglen = bufSize;
2907 		resp->header.arglen = sizeof(*ascii) + bufSize;
2908 		break;
2909 	    }
2910 
2911 	case NGM_ASCII2BINARY:
2912 	    {
2913 		int bufSize = 2000;	/* XXX hard coded constant */
2914 		const struct ng_cmdlist *c;
2915 		const struct ng_parse_type *argstype;
2916 		struct ng_mesg *ascii, *binary;
2917 		int off = 0;
2918 
2919 		/* Data area must contain at least a struct ng_mesg + '\0' */
2920 		ascii = (struct ng_mesg *)msg->data;
2921 		if ((msg->header.arglen < sizeof(*ascii) + 1) ||
2922 		    (ascii->header.arglen < 1) ||
2923 		    (msg->header.arglen < sizeof(*ascii) +
2924 		    ascii->header.arglen)) {
2925 			TRAP_ERROR();
2926 			error = EINVAL;
2927 			break;
2928 		}
2929 		ascii->data[ascii->header.arglen - 1] = '\0';
2930 
2931 		/* Get a response message with lots of room */
2932 		NG_MKRESPONSE(resp, msg, sizeof(*binary) + bufSize, M_NOWAIT);
2933 		if (resp == NULL) {
2934 			error = ENOMEM;
2935 			break;
2936 		}
2937 		binary = (struct ng_mesg *)resp->data;
2938 
2939 		/* Copy ASCII message header to response message payload */
2940 		bcopy(ascii, binary, sizeof(*ascii));
2941 
2942 		/* Find command by matching ASCII command string */
2943 		for (c = here->nd_type->cmdlist;
2944 		    c != NULL && c->name != NULL; c++) {
2945 			if (strcmp(ascii->header.cmdstr, c->name) == 0)
2946 				break;
2947 		}
2948 		if (c == NULL || c->name == NULL) {
2949 			for (c = ng_generic_cmds; c->name != NULL; c++) {
2950 				if (strcmp(ascii->header.cmdstr, c->name) == 0)
2951 					break;
2952 			}
2953 			if (c->name == NULL) {
2954 				NG_FREE_MSG(resp);
2955 				error = ENOSYS;
2956 				break;
2957 			}
2958 		}
2959 
2960 		/* Convert command name to binary */
2961 		binary->header.cmd = c->cmd;
2962 		binary->header.typecookie = c->cookie;
2963 
2964 		/* Convert command arguments to binary */
2965 		argstype = (binary->header.flags & NGF_RESP) ?
2966 		    c->respType : c->mesgType;
2967 		if (argstype == NULL) {
2968 			bufSize = 0;
2969 		} else {
2970 			if ((error = ng_parse(argstype, ascii->data,
2971 			    &off, (u_char *)binary->data, &bufSize)) != 0) {
2972 				NG_FREE_MSG(resp);
2973 				break;
2974 			}
2975 		}
2976 
2977 		/* Return the result */
2978 		binary->header.arglen = bufSize;
2979 		resp->header.arglen = sizeof(*binary) + bufSize;
2980 		break;
2981 	    }
2982 
2983 	case NGM_TEXT_CONFIG:
2984 	case NGM_TEXT_STATUS:
2985 		/*
2986 		 * This one is tricky as it passes the command down to the
2987 		 * actual node, even though it is a generic type command.
2988 		 * This means we must assume that the item/msg is already freed
2989 		 * when control passes back to us.
2990 		 */
2991 		if (here->nd_type->rcvmsg != NULL) {
2992 			NGI_MSG(item) = msg; /* put it back as we found it */
2993 			return((*here->nd_type->rcvmsg)(here, item, lasthook));
2994 		}
2995 		/* Fall through if rcvmsg not supported */
2996 	default:
2997 		TRAP_ERROR();
2998 		error = EINVAL;
2999 	}
3000 	/*
3001 	 * Sometimes a generic message may be statically allocated
3002 	 * to avoid problems with allocating when in tight memeory situations.
3003 	 * Don't free it if it is so.
3004 	 * I break them appart here, because erros may cause a free if the item
3005 	 * in which case we'd be doing it twice.
3006 	 * they are kept together above, to simplify freeing.
3007 	 */
3008 out:
3009 	NG_RESPOND_MSG(error, here, item, resp);
3010 	if (msg)
3011 		NG_FREE_MSG(msg);
3012 	return (error);
3013 }
3014 
3015 /************************************************************************
3016 			Queue element get/free routines
3017 ************************************************************************/
3018 
3019 uma_zone_t			ng_qzone;
3020 static int			maxalloc = 512;	/* limit the damage of a leak */
3021 
3022 TUNABLE_INT("net.graph.maxalloc", &maxalloc);
3023 SYSCTL_INT(_net_graph, OID_AUTO, maxalloc, CTLFLAG_RDTUN, &maxalloc,
3024     0, "Maximum number of queue items to allocate");
3025 
3026 #ifdef	NETGRAPH_DEBUG
3027 static TAILQ_HEAD(, ng_item) ng_itemlist = TAILQ_HEAD_INITIALIZER(ng_itemlist);
3028 static int			allocated;	/* number of items malloc'd */
3029 #endif
3030 
3031 /*
3032  * Get a queue entry.
3033  * This is usually called when a packet first enters netgraph.
3034  * By definition, this is usually from an interrupt, or from a user.
3035  * Users are not so important, but try be quick for the times that it's
3036  * an interrupt.
3037  */
3038 static __inline item_p
3039 ng_getqblk(int flags)
3040 {
3041 	item_p item = NULL;
3042 	int wait;
3043 
3044 	wait = (flags & NG_WAITOK) ? M_WAITOK : M_NOWAIT;
3045 
3046 	item = uma_zalloc(ng_qzone, wait | M_ZERO);
3047 
3048 #ifdef	NETGRAPH_DEBUG
3049 	if (item) {
3050 			mtx_lock(&ngq_mtx);
3051 			TAILQ_INSERT_TAIL(&ng_itemlist, item, all);
3052 			allocated++;
3053 			mtx_unlock(&ngq_mtx);
3054 	}
3055 #endif
3056 
3057 	return (item);
3058 }
3059 
3060 /*
3061  * Release a queue entry
3062  */
3063 void
3064 ng_free_item(item_p item)
3065 {
3066 	/*
3067 	 * The item may hold resources on it's own. We need to free
3068 	 * these before we can free the item. What they are depends upon
3069 	 * what kind of item it is. it is important that nodes zero
3070 	 * out pointers to resources that they remove from the item
3071 	 * or we release them again here.
3072 	 */
3073 	switch (item->el_flags & NGQF_TYPE) {
3074 	case NGQF_DATA:
3075 		/* If we have an mbuf still attached.. */
3076 		NG_FREE_M(_NGI_M(item));
3077 		break;
3078 	case NGQF_MESG:
3079 		_NGI_RETADDR(item) = 0;
3080 		NG_FREE_MSG(_NGI_MSG(item));
3081 		break;
3082 	case NGQF_FN:
3083 	case NGQF_FN2:
3084 		/* nothing to free really, */
3085 		_NGI_FN(item) = NULL;
3086 		_NGI_ARG1(item) = NULL;
3087 		_NGI_ARG2(item) = 0;
3088 		break;
3089 	}
3090 	/* If we still have a node or hook referenced... */
3091 	_NGI_CLR_NODE(item);
3092 	_NGI_CLR_HOOK(item);
3093 
3094 #ifdef	NETGRAPH_DEBUG
3095 	mtx_lock(&ngq_mtx);
3096 	TAILQ_REMOVE(&ng_itemlist, item, all);
3097 	allocated--;
3098 	mtx_unlock(&ngq_mtx);
3099 #endif
3100 	uma_zfree(ng_qzone, item);
3101 }
3102 
3103 /************************************************************************
3104 			Module routines
3105 ************************************************************************/
3106 
3107 /*
3108  * Handle the loading/unloading of a netgraph node type module
3109  */
3110 int
3111 ng_mod_event(module_t mod, int event, void *data)
3112 {
3113 	struct ng_type *const type = data;
3114 	int s, error = 0;
3115 
3116 	switch (event) {
3117 	case MOD_LOAD:
3118 
3119 		/* Register new netgraph node type */
3120 		s = splnet();
3121 		if ((error = ng_newtype(type)) != 0) {
3122 			splx(s);
3123 			break;
3124 		}
3125 
3126 		/* Call type specific code */
3127 		if (type->mod_event != NULL)
3128 			if ((error = (*type->mod_event)(mod, event, data))) {
3129 				mtx_lock(&ng_typelist_mtx);
3130 				type->refs--;	/* undo it */
3131 				LIST_REMOVE(type, types);
3132 				mtx_unlock(&ng_typelist_mtx);
3133 			}
3134 		splx(s);
3135 		break;
3136 
3137 	case MOD_UNLOAD:
3138 		s = splnet();
3139 		if (type->refs > 1) {		/* make sure no nodes exist! */
3140 			error = EBUSY;
3141 		} else {
3142 			if (type->refs == 0) {
3143 				/* failed load, nothing to undo */
3144 				splx(s);
3145 				break;
3146 			}
3147 			if (type->mod_event != NULL) {	/* check with type */
3148 				error = (*type->mod_event)(mod, event, data);
3149 				if (error != 0) {	/* type refuses.. */
3150 					splx(s);
3151 					break;
3152 				}
3153 			}
3154 			mtx_lock(&ng_typelist_mtx);
3155 			LIST_REMOVE(type, types);
3156 			mtx_unlock(&ng_typelist_mtx);
3157 		}
3158 		splx(s);
3159 		break;
3160 
3161 	default:
3162 		if (type->mod_event != NULL)
3163 			error = (*type->mod_event)(mod, event, data);
3164 		else
3165 			error = EOPNOTSUPP;		/* XXX ? */
3166 		break;
3167 	}
3168 	return (error);
3169 }
3170 
3171 /*
3172  * Handle loading and unloading for this code.
3173  * The only thing we need to link into is the NETISR strucure.
3174  */
3175 static int
3176 ngb_mod_event(module_t mod, int event, void *data)
3177 {
3178 	int error = 0;
3179 
3180 	switch (event) {
3181 	case MOD_LOAD:
3182 		/* Initialize everything. */
3183 		NG_WORKLIST_LOCK_INIT();
3184 		mtx_init(&ng_typelist_mtx, "netgraph types mutex", NULL,
3185 		    MTX_DEF);
3186 		mtx_init(&ng_nodelist_mtx, "netgraph nodelist mutex", NULL,
3187 		    MTX_DEF);
3188 		mtx_init(&ng_idhash_mtx, "netgraph idhash mutex", NULL,
3189 		    MTX_DEF);
3190 		mtx_init(&ng_topo_mtx, "netgraph topology mutex", NULL,
3191 		    MTX_DEF);
3192 #ifdef	NETGRAPH_DEBUG
3193 		mtx_init(&ngq_mtx, "netgraph item list mutex", NULL,
3194 		    MTX_DEF);
3195 #endif
3196 		ng_qzone = uma_zcreate("NetGraph items", sizeof(struct ng_item),
3197 		    NULL, NULL, NULL, NULL, UMA_ALIGN_CACHE, 0);
3198 		uma_zone_set_max(ng_qzone, maxalloc);
3199 		netisr_register(NETISR_NETGRAPH, (netisr_t *)ngintr, NULL,
3200 		    NETISR_MPSAFE);
3201 		break;
3202 	case MOD_UNLOAD:
3203 		/* You can't unload it because an interface may be using it. */
3204 		error = EBUSY;
3205 		break;
3206 	default:
3207 		error = EOPNOTSUPP;
3208 		break;
3209 	}
3210 	return (error);
3211 }
3212 
3213 static moduledata_t netgraph_mod = {
3214 	"netgraph",
3215 	ngb_mod_event,
3216 	(NULL)
3217 };
3218 DECLARE_MODULE(netgraph, netgraph_mod, SI_SUB_NETGRAPH, SI_ORDER_MIDDLE);
3219 SYSCTL_NODE(_net, OID_AUTO, graph, CTLFLAG_RW, 0, "netgraph Family");
3220 SYSCTL_INT(_net_graph, OID_AUTO, abi_version, CTLFLAG_RD, 0, NG_ABI_VERSION,"");
3221 SYSCTL_INT(_net_graph, OID_AUTO, msg_version, CTLFLAG_RD, 0, NG_VERSION, "");
3222 
3223 #ifdef	NETGRAPH_DEBUG
3224 void
3225 dumphook (hook_p hook, char *file, int line)
3226 {
3227 	printf("hook: name %s, %d refs, Last touched:\n",
3228 		_NG_HOOK_NAME(hook), hook->hk_refs);
3229 	printf("	Last active @ %s, line %d\n",
3230 		hook->lastfile, hook->lastline);
3231 	if (line) {
3232 		printf(" problem discovered at file %s, line %d\n", file, line);
3233 	}
3234 }
3235 
3236 void
3237 dumpnode(node_p node, char *file, int line)
3238 {
3239 	printf("node: ID [%x]: type '%s', %d hooks, flags 0x%x, %d refs, %s:\n",
3240 		_NG_NODE_ID(node), node->nd_type->name,
3241 		node->nd_numhooks, node->nd_flags,
3242 		node->nd_refs, node->nd_name);
3243 	printf("	Last active @ %s, line %d\n",
3244 		node->lastfile, node->lastline);
3245 	if (line) {
3246 		printf(" problem discovered at file %s, line %d\n", file, line);
3247 	}
3248 }
3249 
3250 void
3251 dumpitem(item_p item, char *file, int line)
3252 {
3253 	printf(" ACTIVE item, last used at %s, line %d",
3254 		item->lastfile, item->lastline);
3255 	switch(item->el_flags & NGQF_TYPE) {
3256 	case NGQF_DATA:
3257 		printf(" - [data]\n");
3258 		break;
3259 	case NGQF_MESG:
3260 		printf(" - retaddr[%d]:\n", _NGI_RETADDR(item));
3261 		break;
3262 	case NGQF_FN:
3263 		printf(" - fn@%p (%p, %p, %p, %d (%x))\n",
3264 			_NGI_FN(item),
3265 			_NGI_NODE(item),
3266 			_NGI_HOOK(item),
3267 			item->body.fn.fn_arg1,
3268 			item->body.fn.fn_arg2,
3269 			item->body.fn.fn_arg2);
3270 		break;
3271 	case NGQF_FN2:
3272 		printf(" - fn2@%p (%p, %p, %p, %d (%x))\n",
3273 			_NGI_FN2(item),
3274 			_NGI_NODE(item),
3275 			_NGI_HOOK(item),
3276 			item->body.fn.fn_arg1,
3277 			item->body.fn.fn_arg2,
3278 			item->body.fn.fn_arg2);
3279 		break;
3280 	}
3281 	if (line) {
3282 		printf(" problem discovered at file %s, line %d\n", file, line);
3283 		if (_NGI_NODE(item)) {
3284 			printf("node %p ([%x])\n",
3285 				_NGI_NODE(item), ng_node2ID(_NGI_NODE(item)));
3286 		}
3287 	}
3288 }
3289 
3290 static void
3291 ng_dumpitems(void)
3292 {
3293 	item_p item;
3294 	int i = 1;
3295 	TAILQ_FOREACH(item, &ng_itemlist, all) {
3296 		printf("[%d] ", i++);
3297 		dumpitem(item, NULL, 0);
3298 	}
3299 }
3300 
3301 static void
3302 ng_dumpnodes(void)
3303 {
3304 	node_p node;
3305 	int i = 1;
3306 	mtx_lock(&ng_nodelist_mtx);
3307 	SLIST_FOREACH(node, &ng_allnodes, nd_all) {
3308 		printf("[%d] ", i++);
3309 		dumpnode(node, NULL, 0);
3310 	}
3311 	mtx_unlock(&ng_nodelist_mtx);
3312 }
3313 
3314 static void
3315 ng_dumphooks(void)
3316 {
3317 	hook_p hook;
3318 	int i = 1;
3319 	mtx_lock(&ng_nodelist_mtx);
3320 	SLIST_FOREACH(hook, &ng_allhooks, hk_all) {
3321 		printf("[%d] ", i++);
3322 		dumphook(hook, NULL, 0);
3323 	}
3324 	mtx_unlock(&ng_nodelist_mtx);
3325 }
3326 
3327 static int
3328 sysctl_debug_ng_dump_items(SYSCTL_HANDLER_ARGS)
3329 {
3330 	int error;
3331 	int val;
3332 	int i;
3333 
3334 	val = allocated;
3335 	i = 1;
3336 	error = sysctl_handle_int(oidp, &val, 0, req);
3337 	if (error != 0 || req->newptr == NULL)
3338 		return (error);
3339 	if (val == 42) {
3340 		ng_dumpitems();
3341 		ng_dumpnodes();
3342 		ng_dumphooks();
3343 	}
3344 	return (0);
3345 }
3346 
3347 SYSCTL_PROC(_debug, OID_AUTO, ng_dump_items, CTLTYPE_INT | CTLFLAG_RW,
3348     0, sizeof(int), sysctl_debug_ng_dump_items, "I", "Number of allocated items");
3349 #endif	/* NETGRAPH_DEBUG */
3350 
3351 
3352 /***********************************************************************
3353 * Worklist routines
3354 **********************************************************************/
3355 /* NETISR thread enters here */
3356 /*
3357  * Pick a node off the list of nodes with work,
3358  * try get an item to process off it.
3359  * If there are no more, remove the node from the list.
3360  */
3361 static void
3362 ngintr(void)
3363 {
3364 	item_p item;
3365 	node_p  node = NULL;
3366 
3367 	for (;;) {
3368 		NG_WORKLIST_LOCK();
3369 		node = TAILQ_FIRST(&ng_worklist);
3370 		if (!node) {
3371 			NG_WORKLIST_UNLOCK();
3372 			break;
3373 		}
3374 		node->nd_flags &= ~NGF_WORKQ;
3375 		TAILQ_REMOVE(&ng_worklist, node, nd_work);
3376 		NG_WORKLIST_UNLOCK();
3377 		CTR3(KTR_NET, "%20s: node [%x] (%p) taken off worklist",
3378 		    __func__, node->nd_ID, node);
3379 		/*
3380 		 * We have the node. We also take over the reference
3381 		 * that the list had on it.
3382 		 * Now process as much as you can, until it won't
3383 		 * let you have another item off the queue.
3384 		 * All this time, keep the reference
3385 		 * that lets us be sure that the node still exists.
3386 		 * Let the reference go at the last minute.
3387 		 * ng_dequeue will put us back on the worklist
3388 		 * if there is more too do. This may be of use if there
3389 		 * are Multiple Processors and multiple Net threads in the
3390 		 * future.
3391 		 */
3392 		for (;;) {
3393 			int rw;
3394 
3395 			NG_QUEUE_LOCK(&node->nd_input_queue);
3396 			item = ng_dequeue(&node->nd_input_queue, &rw);
3397 			if (item == NULL) {
3398 				NG_QUEUE_UNLOCK(&node->nd_input_queue);
3399 				break; /* go look for another node */
3400 			} else {
3401 				NG_QUEUE_UNLOCK(&node->nd_input_queue);
3402 				NGI_GET_NODE(item, node); /* zaps stored node */
3403 				ng_apply_item(node, item, rw);
3404 				NG_NODE_UNREF(node);
3405 			}
3406 		}
3407 		NG_NODE_UNREF(node);
3408 	}
3409 }
3410 
3411 static void
3412 ng_worklist_remove(node_p node)
3413 {
3414 	mtx_assert(&node->nd_input_queue.q_mtx, MA_OWNED);
3415 
3416 	NG_WORKLIST_LOCK();
3417 	if (node->nd_flags & NGF_WORKQ) {
3418 		node->nd_flags &= ~NGF_WORKQ;
3419 		TAILQ_REMOVE(&ng_worklist, node, nd_work);
3420 		NG_WORKLIST_UNLOCK();
3421 		NG_NODE_UNREF(node);
3422 		CTR3(KTR_NET, "%20s: node [%x] (%p) removed from worklist",
3423 		    __func__, node->nd_ID, node);
3424 	} else {
3425 		NG_WORKLIST_UNLOCK();
3426 	}
3427 }
3428 
3429 /*
3430  * XXX
3431  * It's posible that a debugging NG_NODE_REF may need
3432  * to be outside the mutex zone
3433  */
3434 static void
3435 ng_setisr(node_p node)
3436 {
3437 
3438 	mtx_assert(&node->nd_input_queue.q_mtx, MA_OWNED);
3439 
3440 	if ((node->nd_flags & NGF_WORKQ) == 0) {
3441 		/*
3442 		 * If we are not already on the work queue,
3443 		 * then put us on.
3444 		 */
3445 		node->nd_flags |= NGF_WORKQ;
3446 		NG_WORKLIST_LOCK();
3447 		TAILQ_INSERT_TAIL(&ng_worklist, node, nd_work);
3448 		NG_WORKLIST_UNLOCK();
3449 		NG_NODE_REF(node); /* XXX fafe in mutex? */
3450 		CTR3(KTR_NET, "%20s: node [%x] (%p) put on worklist", __func__,
3451 		    node->nd_ID, node);
3452 	} else
3453 		CTR3(KTR_NET, "%20s: node [%x] (%p) already on worklist",
3454 		    __func__, node->nd_ID, node);
3455 	schednetisr(NETISR_NETGRAPH);
3456 }
3457 
3458 
3459 /***********************************************************************
3460 * Externally useable functions to set up a queue item ready for sending
3461 ***********************************************************************/
3462 
3463 #ifdef	NETGRAPH_DEBUG
3464 #define	ITEM_DEBUG_CHECKS						\
3465 	do {								\
3466 		if (NGI_NODE(item) ) {					\
3467 			printf("item already has node");		\
3468 			kdb_enter(KDB_WHY_NETGRAPH, "has node");	\
3469 			NGI_CLR_NODE(item);				\
3470 		}							\
3471 		if (NGI_HOOK(item) ) {					\
3472 			printf("item already has hook");		\
3473 			kdb_enter(KDB_WHY_NETGRAPH, "has hook");	\
3474 			NGI_CLR_HOOK(item);				\
3475 		}							\
3476 	} while (0)
3477 #else
3478 #define ITEM_DEBUG_CHECKS
3479 #endif
3480 
3481 /*
3482  * Put mbuf into the item.
3483  * Hook and node references will be removed when the item is dequeued.
3484  * (or equivalent)
3485  * (XXX) Unsafe because no reference held by peer on remote node.
3486  * remote node might go away in this timescale.
3487  * We know the hooks can't go away because that would require getting
3488  * a writer item on both nodes and we must have at least a  reader
3489  * here to be able to do this.
3490  * Note that the hook loaded is the REMOTE hook.
3491  *
3492  * This is possibly in the critical path for new data.
3493  */
3494 item_p
3495 ng_package_data(struct mbuf *m, int flags)
3496 {
3497 	item_p item;
3498 
3499 	if ((item = ng_getqblk(flags)) == NULL) {
3500 		NG_FREE_M(m);
3501 		return (NULL);
3502 	}
3503 	ITEM_DEBUG_CHECKS;
3504 	item->el_flags = NGQF_DATA | NGQF_READER;
3505 	item->el_next = NULL;
3506 	NGI_M(item) = m;
3507 	return (item);
3508 }
3509 
3510 /*
3511  * Allocate a queue item and put items into it..
3512  * Evaluate the address as this will be needed to queue it and
3513  * to work out what some of the fields should be.
3514  * Hook and node references will be removed when the item is dequeued.
3515  * (or equivalent)
3516  */
3517 item_p
3518 ng_package_msg(struct ng_mesg *msg, int flags)
3519 {
3520 	item_p item;
3521 
3522 	if ((item = ng_getqblk(flags)) == NULL) {
3523 		NG_FREE_MSG(msg);
3524 		return (NULL);
3525 	}
3526 	ITEM_DEBUG_CHECKS;
3527 	/* Messages items count as writers unless explicitly exempted. */
3528 	if (msg->header.cmd & NGM_READONLY)
3529 		item->el_flags = NGQF_MESG | NGQF_READER;
3530 	else
3531 		item->el_flags = NGQF_MESG | NGQF_WRITER;
3532 	item->el_next = NULL;
3533 	/*
3534 	 * Set the current lasthook into the queue item
3535 	 */
3536 	NGI_MSG(item) = msg;
3537 	NGI_RETADDR(item) = 0;
3538 	return (item);
3539 }
3540 
3541 
3542 
3543 #define SET_RETADDR(item, here, retaddr)				\
3544 	do {	/* Data or fn items don't have retaddrs */		\
3545 		if ((item->el_flags & NGQF_TYPE) == NGQF_MESG) {	\
3546 			if (retaddr) {					\
3547 				NGI_RETADDR(item) = retaddr;		\
3548 			} else {					\
3549 				/*					\
3550 				 * The old return address should be ok.	\
3551 				 * If there isn't one, use the address	\
3552 				 * here.				\
3553 				 */					\
3554 				if (NGI_RETADDR(item) == 0) {		\
3555 					NGI_RETADDR(item)		\
3556 						= ng_node2ID(here);	\
3557 				}					\
3558 			}						\
3559 		}							\
3560 	} while (0)
3561 
3562 int
3563 ng_address_hook(node_p here, item_p item, hook_p hook, ng_ID_t retaddr)
3564 {
3565 	hook_p peer;
3566 	node_p peernode;
3567 	ITEM_DEBUG_CHECKS;
3568 	/*
3569 	 * Quick sanity check..
3570 	 * Since a hook holds a reference on it's node, once we know
3571 	 * that the peer is still connected (even if invalid,) we know
3572 	 * that the peer node is present, though maybe invalid.
3573 	 */
3574 	if ((hook == NULL)
3575 	|| NG_HOOK_NOT_VALID(hook)
3576 	|| (NG_HOOK_PEER(hook) == NULL)
3577 	|| NG_HOOK_NOT_VALID(NG_HOOK_PEER(hook))
3578 	|| NG_NODE_NOT_VALID(NG_PEER_NODE(hook))) {
3579 		NG_FREE_ITEM(item);
3580 		TRAP_ERROR();
3581 		return (ENETDOWN);
3582 	}
3583 
3584 	/*
3585 	 * Transfer our interest to the other (peer) end.
3586 	 */
3587 	peer = NG_HOOK_PEER(hook);
3588 	NG_HOOK_REF(peer);
3589 	NGI_SET_HOOK(item, peer);
3590 	peernode = NG_PEER_NODE(hook);
3591 	NG_NODE_REF(peernode);
3592 	NGI_SET_NODE(item, peernode);
3593 	SET_RETADDR(item, here, retaddr);
3594 	return (0);
3595 }
3596 
3597 int
3598 ng_address_path(node_p here, item_p item, char *address, ng_ID_t retaddr)
3599 {
3600 	node_p	dest = NULL;
3601 	hook_p	hook = NULL;
3602 	int	error;
3603 
3604 	ITEM_DEBUG_CHECKS;
3605 	/*
3606 	 * Note that ng_path2noderef increments the reference count
3607 	 * on the node for us if it finds one. So we don't have to.
3608 	 */
3609 	error = ng_path2noderef(here, address, &dest, &hook);
3610 	if (error) {
3611 		NG_FREE_ITEM(item);
3612 		return (error);
3613 	}
3614 	NGI_SET_NODE(item, dest);
3615 	if ( hook) {
3616 		NG_HOOK_REF(hook);	/* don't let it go while on the queue */
3617 		NGI_SET_HOOK(item, hook);
3618 	}
3619 	SET_RETADDR(item, here, retaddr);
3620 	return (0);
3621 }
3622 
3623 int
3624 ng_address_ID(node_p here, item_p item, ng_ID_t ID, ng_ID_t retaddr)
3625 {
3626 	node_p dest;
3627 
3628 	ITEM_DEBUG_CHECKS;
3629 	/*
3630 	 * Find the target node.
3631 	 */
3632 	dest = ng_ID2noderef(ID); /* GETS REFERENCE! */
3633 	if (dest == NULL) {
3634 		NG_FREE_ITEM(item);
3635 		TRAP_ERROR();
3636 		return(EINVAL);
3637 	}
3638 	/* Fill out the contents */
3639 	NGI_SET_NODE(item, dest);
3640 	NGI_CLR_HOOK(item);
3641 	SET_RETADDR(item, here, retaddr);
3642 	return (0);
3643 }
3644 
3645 /*
3646  * special case to send a message to self (e.g. destroy node)
3647  * Possibly indicate an arrival hook too.
3648  * Useful for removing that hook :-)
3649  */
3650 item_p
3651 ng_package_msg_self(node_p here, hook_p hook, struct ng_mesg *msg)
3652 {
3653 	item_p item;
3654 
3655 	/*
3656 	 * Find the target node.
3657 	 * If there is a HOOK argument, then use that in preference
3658 	 * to the address.
3659 	 */
3660 	if ((item = ng_getqblk(NG_NOFLAGS)) == NULL) {
3661 		NG_FREE_MSG(msg);
3662 		return (NULL);
3663 	}
3664 
3665 	/* Fill out the contents */
3666 	item->el_flags = NGQF_MESG | NGQF_WRITER;
3667 	item->el_next = NULL;
3668 	NG_NODE_REF(here);
3669 	NGI_SET_NODE(item, here);
3670 	if (hook) {
3671 		NG_HOOK_REF(hook);
3672 		NGI_SET_HOOK(item, hook);
3673 	}
3674 	NGI_MSG(item) = msg;
3675 	NGI_RETADDR(item) = ng_node2ID(here);
3676 	return (item);
3677 }
3678 
3679 /*
3680  * Send ng_item_fn function call to the specified node.
3681  */
3682 
3683 int
3684 ng_send_fn(node_p node, hook_p hook, ng_item_fn *fn, void * arg1, int arg2)
3685 {
3686 
3687 	return ng_send_fn1(node, hook, fn, arg1, arg2, NG_NOFLAGS);
3688 }
3689 
3690 int
3691 ng_send_fn1(node_p node, hook_p hook, ng_item_fn *fn, void * arg1, int arg2,
3692 	int flags)
3693 {
3694 	item_p item;
3695 
3696 	if ((item = ng_getqblk(flags)) == NULL) {
3697 		return (ENOMEM);
3698 	}
3699 	item->el_flags = NGQF_FN | NGQF_WRITER;
3700 	NG_NODE_REF(node); /* and one for the item */
3701 	NGI_SET_NODE(item, node);
3702 	if (hook) {
3703 		NG_HOOK_REF(hook);
3704 		NGI_SET_HOOK(item, hook);
3705 	}
3706 	NGI_FN(item) = fn;
3707 	NGI_ARG1(item) = arg1;
3708 	NGI_ARG2(item) = arg2;
3709 	return(ng_snd_item(item, flags));
3710 }
3711 
3712 /*
3713  * Send ng_item_fn2 function call to the specified node.
3714  *
3715  * If an optional pitem parameter is supplied, its apply
3716  * callback will be copied to the new item. If also NG_REUSE_ITEM
3717  * flag is set, no new item will be allocated, but pitem will
3718  * be used.
3719  */
3720 int
3721 ng_send_fn2(node_p node, hook_p hook, item_p pitem, ng_item_fn2 *fn, void *arg1,
3722 	int arg2, int flags)
3723 {
3724 	item_p item;
3725 
3726 	KASSERT((pitem != NULL || (flags & NG_REUSE_ITEM) == 0),
3727 	    ("%s: NG_REUSE_ITEM but no pitem", __func__));
3728 
3729 	/*
3730 	 * Allocate a new item if no supplied or
3731 	 * if we can't use supplied one.
3732 	 */
3733 	if (pitem == NULL || (flags & NG_REUSE_ITEM) == 0) {
3734 		if ((item = ng_getqblk(flags)) == NULL)
3735 			return (ENOMEM);
3736 	} else
3737 		item = pitem;
3738 
3739 	item->el_flags = NGQF_FN2 | NGQF_WRITER;
3740 	NG_NODE_REF(node); /* and one for the item */
3741 	NGI_SET_NODE(item, node);
3742 	if (hook) {
3743 		NG_HOOK_REF(hook);
3744 		NGI_SET_HOOK(item, hook);
3745 	}
3746 	NGI_FN2(item) = fn;
3747 	NGI_ARG1(item) = arg1;
3748 	NGI_ARG2(item) = arg2;
3749 	if (pitem != NULL && (flags & NG_REUSE_ITEM) == 0)
3750 		item->apply = pitem->apply;
3751 	return(ng_snd_item(item, flags));
3752 }
3753 
3754 /*
3755  * Official timeout routines for Netgraph nodes.
3756  */
3757 static void
3758 ng_callout_trampoline(void *arg)
3759 {
3760 	item_p item = arg;
3761 
3762 	ng_snd_item(item, 0);
3763 }
3764 
3765 
3766 int
3767 ng_callout(struct callout *c, node_p node, hook_p hook, int ticks,
3768     ng_item_fn *fn, void * arg1, int arg2)
3769 {
3770 	item_p item, oitem;
3771 
3772 	if ((item = ng_getqblk(NG_NOFLAGS)) == NULL)
3773 		return (ENOMEM);
3774 
3775 	item->el_flags = NGQF_FN | NGQF_WRITER;
3776 	NG_NODE_REF(node);		/* and one for the item */
3777 	NGI_SET_NODE(item, node);
3778 	if (hook) {
3779 		NG_HOOK_REF(hook);
3780 		NGI_SET_HOOK(item, hook);
3781 	}
3782 	NGI_FN(item) = fn;
3783 	NGI_ARG1(item) = arg1;
3784 	NGI_ARG2(item) = arg2;
3785 	oitem = c->c_arg;
3786 	if (callout_reset(c, ticks, &ng_callout_trampoline, item) == 1 &&
3787 	    oitem != NULL)
3788 		NG_FREE_ITEM(oitem);
3789 	return (0);
3790 }
3791 
3792 /* A special modified version of untimeout() */
3793 int
3794 ng_uncallout(struct callout *c, node_p node)
3795 {
3796 	item_p item;
3797 	int rval;
3798 
3799 	KASSERT(c != NULL, ("ng_uncallout: NULL callout"));
3800 	KASSERT(node != NULL, ("ng_uncallout: NULL node"));
3801 
3802 	rval = callout_stop(c);
3803 	item = c->c_arg;
3804 	/* Do an extra check */
3805 	if ((rval > 0) && (c->c_func == &ng_callout_trampoline) &&
3806 	    (NGI_NODE(item) == node)) {
3807 		/*
3808 		 * We successfully removed it from the queue before it ran
3809 		 * So now we need to unreference everything that was
3810 		 * given extra references. (NG_FREE_ITEM does this).
3811 		 */
3812 		NG_FREE_ITEM(item);
3813 	}
3814 	c->c_arg = NULL;
3815 
3816 	return (rval);
3817 }
3818 
3819 /*
3820  * Set the address, if none given, give the node here.
3821  */
3822 void
3823 ng_replace_retaddr(node_p here, item_p item, ng_ID_t retaddr)
3824 {
3825 	if (retaddr) {
3826 		NGI_RETADDR(item) = retaddr;
3827 	} else {
3828 		/*
3829 		 * The old return address should be ok.
3830 		 * If there isn't one, use the address here.
3831 		 */
3832 		NGI_RETADDR(item) = ng_node2ID(here);
3833 	}
3834 }
3835 
3836 #define TESTING
3837 #ifdef TESTING
3838 /* just test all the macros */
3839 void
3840 ng_macro_test(item_p item);
3841 void
3842 ng_macro_test(item_p item)
3843 {
3844 	node_p node = NULL;
3845 	hook_p hook = NULL;
3846 	struct mbuf *m;
3847 	struct ng_mesg *msg;
3848 	ng_ID_t retaddr;
3849 	int	error;
3850 
3851 	NGI_GET_M(item, m);
3852 	NGI_GET_MSG(item, msg);
3853 	retaddr = NGI_RETADDR(item);
3854 	NG_SEND_DATA(error, hook, m, NULL);
3855 	NG_SEND_DATA_ONLY(error, hook, m);
3856 	NG_FWD_NEW_DATA(error, item, hook, m);
3857 	NG_FWD_ITEM_HOOK(error, item, hook);
3858 	NG_SEND_MSG_HOOK(error, node, msg, hook, retaddr);
3859 	NG_SEND_MSG_ID(error, node, msg, retaddr, retaddr);
3860 	NG_SEND_MSG_PATH(error, node, msg, ".:", retaddr);
3861 	NG_FWD_MSG_HOOK(error, node, item, hook, retaddr);
3862 }
3863 #endif /* TESTING */
3864 
3865