xref: /freebsd/sys/netgraph/ng_base.c (revision bc7512cc58af2e8bbe5bbf5ca0059b1daa1da897)
1 /*-
2  * Copyright (c) 1996-1999 Whistle Communications, Inc.
3  * All rights reserved.
4  *
5  * Subject to the following obligations and disclaimer of warranty, use and
6  * redistribution of this software, in source or object code forms, with or
7  * without modifications are expressly permitted by Whistle Communications;
8  * provided, however, that:
9  * 1. Any and all reproductions of the source or object code must include the
10  *    copyright notice above and the following disclaimer of warranties; and
11  * 2. No rights are granted, in any manner or form, to use Whistle
12  *    Communications, Inc. trademarks, including the mark "WHISTLE
13  *    COMMUNICATIONS" on advertising, endorsements, or otherwise except as
14  *    such appears in the above copyright notice or in the software.
15  *
16  * THIS SOFTWARE IS BEING PROVIDED BY WHISTLE COMMUNICATIONS "AS IS", AND
17  * TO THE MAXIMUM EXTENT PERMITTED BY LAW, WHISTLE COMMUNICATIONS MAKES NO
18  * REPRESENTATIONS OR WARRANTIES, EXPRESS OR IMPLIED, REGARDING THIS SOFTWARE,
19  * INCLUDING WITHOUT LIMITATION, ANY AND ALL IMPLIED WARRANTIES OF
20  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, OR NON-INFRINGEMENT.
21  * WHISTLE COMMUNICATIONS DOES NOT WARRANT, GUARANTEE, OR MAKE ANY
22  * REPRESENTATIONS REGARDING THE USE OF, OR THE RESULTS OF THE USE OF THIS
23  * SOFTWARE IN TERMS OF ITS CORRECTNESS, ACCURACY, RELIABILITY OR OTHERWISE.
24  * IN NO EVENT SHALL WHISTLE COMMUNICATIONS BE LIABLE FOR ANY DAMAGES
25  * RESULTING FROM OR ARISING OUT OF ANY USE OF THIS SOFTWARE, INCLUDING
26  * WITHOUT LIMITATION, ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY,
27  * PUNITIVE, OR CONSEQUENTIAL DAMAGES, PROCUREMENT OF SUBSTITUTE GOODS OR
28  * SERVICES, LOSS OF USE, DATA OR PROFITS, HOWEVER CAUSED AND UNDER ANY
29  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
30  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
31  * THIS SOFTWARE, EVEN IF WHISTLE COMMUNICATIONS IS ADVISED OF THE POSSIBILITY
32  * OF SUCH DAMAGE.
33  *
34  * Authors: Julian Elischer <julian@freebsd.org>
35  *          Archie Cobbs <archie@freebsd.org>
36  *
37  * $FreeBSD$
38  * $Whistle: ng_base.c,v 1.39 1999/01/28 23:54:53 julian Exp $
39  */
40 
41 /*
42  * This file implements the base netgraph code.
43  */
44 
45 #include <sys/param.h>
46 #include <sys/systm.h>
47 #include <sys/ctype.h>
48 #include <sys/hash.h>
49 #include <sys/kdb.h>
50 #include <sys/kernel.h>
51 #include <sys/kthread.h>
52 #include <sys/ktr.h>
53 #include <sys/limits.h>
54 #include <sys/lock.h>
55 #include <sys/malloc.h>
56 #include <sys/mbuf.h>
57 #include <sys/proc.h>
58 #include <sys/epoch.h>
59 #include <sys/queue.h>
60 #include <sys/refcount.h>
61 #include <sys/rwlock.h>
62 #include <sys/smp.h>
63 #include <sys/sysctl.h>
64 #include <sys/syslog.h>
65 #include <sys/unistd.h>
66 #include <machine/cpu.h>
67 #include <vm/uma.h>
68 
69 #include <net/netisr.h>
70 #include <net/vnet.h>
71 
72 #include <netgraph/ng_message.h>
73 #include <netgraph/netgraph.h>
74 #include <netgraph/ng_parse.h>
75 
76 MODULE_VERSION(netgraph, NG_ABI_VERSION);
77 
78 /* Mutex to protect topology events. */
79 static struct rwlock	ng_topo_lock;
80 #define	TOPOLOGY_RLOCK()	rw_rlock(&ng_topo_lock)
81 #define	TOPOLOGY_RUNLOCK()	rw_runlock(&ng_topo_lock)
82 #define	TOPOLOGY_WLOCK()	rw_wlock(&ng_topo_lock)
83 #define	TOPOLOGY_WUNLOCK()	rw_wunlock(&ng_topo_lock)
84 #define	TOPOLOGY_NOTOWNED()	rw_assert(&ng_topo_lock, RA_UNLOCKED)
85 
86 #ifdef	NETGRAPH_DEBUG
87 static struct mtx	ng_nodelist_mtx; /* protects global node/hook lists */
88 static struct mtx	ngq_mtx;	/* protects the queue item list */
89 
90 static SLIST_HEAD(, ng_node) ng_allnodes;
91 static LIST_HEAD(, ng_node) ng_freenodes; /* in debug, we never free() them */
92 static SLIST_HEAD(, ng_hook) ng_allhooks;
93 static LIST_HEAD(, ng_hook) ng_freehooks; /* in debug, we never free() them */
94 
95 static void ng_dumpitems(void);
96 static void ng_dumpnodes(void);
97 static void ng_dumphooks(void);
98 
99 #endif	/* NETGRAPH_DEBUG */
100 /*
101  * DEAD versions of the structures.
102  * In order to avoid races, it is sometimes necessary to point
103  * at SOMETHING even though theoretically, the current entity is
104  * INVALID. Use these to avoid these races.
105  */
106 struct ng_type ng_deadtype = {
107 	NG_ABI_VERSION,
108 	"dead",
109 	NULL,	/* modevent */
110 	NULL,	/* constructor */
111 	NULL,	/* rcvmsg */
112 	NULL,	/* shutdown */
113 	NULL,	/* newhook */
114 	NULL,	/* findhook */
115 	NULL,	/* connect */
116 	NULL,	/* rcvdata */
117 	NULL,	/* disconnect */
118 	NULL, 	/* cmdlist */
119 };
120 
121 struct ng_node ng_deadnode = {
122 	"dead",
123 	&ng_deadtype,
124 	NGF_INVALID,
125 	0,	/* numhooks */
126 	NULL,	/* private */
127 	0,	/* ID */
128 	LIST_HEAD_INITIALIZER(ng_deadnode.nd_hooks),
129 	{},	/* all_nodes list entry */
130 	{},	/* id hashtable list entry */
131 	{	0,
132 		0,
133 		{}, /* should never use! (should hang) */
134 		{}, /* workqueue entry */
135 		STAILQ_HEAD_INITIALIZER(ng_deadnode.nd_input_queue.queue),
136 	},
137 	1,	/* refs */
138 	NULL,	/* vnet */
139 #ifdef	NETGRAPH_DEBUG
140 	ND_MAGIC,
141 	__FILE__,
142 	__LINE__,
143 	{NULL}
144 #endif	/* NETGRAPH_DEBUG */
145 };
146 
147 struct ng_hook ng_deadhook = {
148 	"dead",
149 	NULL,		/* private */
150 	HK_INVALID | HK_DEAD,
151 	0,		/* undefined data link type */
152 	&ng_deadhook,	/* Peer is self */
153 	&ng_deadnode,	/* attached to deadnode */
154 	{},		/* hooks list */
155 	NULL,		/* override rcvmsg() */
156 	NULL,		/* override rcvdata() */
157 	1,		/* refs always >= 1 */
158 #ifdef	NETGRAPH_DEBUG
159 	HK_MAGIC,
160 	__FILE__,
161 	__LINE__,
162 	{NULL}
163 #endif	/* NETGRAPH_DEBUG */
164 };
165 
166 /*
167  * END DEAD STRUCTURES
168  */
169 /* List nodes with unallocated work */
170 static STAILQ_HEAD(, ng_node) ng_worklist = STAILQ_HEAD_INITIALIZER(ng_worklist);
171 static struct mtx	ng_worklist_mtx;   /* MUST LOCK NODE FIRST */
172 
173 /* List of installed types */
174 static LIST_HEAD(, ng_type) ng_typelist;
175 static struct rwlock	ng_typelist_lock;
176 #define	TYPELIST_RLOCK()	rw_rlock(&ng_typelist_lock)
177 #define	TYPELIST_RUNLOCK()	rw_runlock(&ng_typelist_lock)
178 #define	TYPELIST_WLOCK()	rw_wlock(&ng_typelist_lock)
179 #define	TYPELIST_WUNLOCK()	rw_wunlock(&ng_typelist_lock)
180 
181 /* Hash related definitions. */
182 LIST_HEAD(nodehash, ng_node);
183 VNET_DEFINE_STATIC(struct nodehash *, ng_ID_hash);
184 VNET_DEFINE_STATIC(u_long, ng_ID_hmask);
185 VNET_DEFINE_STATIC(u_long, ng_nodes);
186 VNET_DEFINE_STATIC(struct nodehash *, ng_name_hash);
187 VNET_DEFINE_STATIC(u_long, ng_name_hmask);
188 VNET_DEFINE_STATIC(u_long, ng_named_nodes);
189 #define	V_ng_ID_hash		VNET(ng_ID_hash)
190 #define	V_ng_ID_hmask		VNET(ng_ID_hmask)
191 #define	V_ng_nodes		VNET(ng_nodes)
192 #define	V_ng_name_hash		VNET(ng_name_hash)
193 #define	V_ng_name_hmask		VNET(ng_name_hmask)
194 #define	V_ng_named_nodes	VNET(ng_named_nodes)
195 
196 static struct rwlock	ng_idhash_lock;
197 #define	IDHASH_RLOCK()		rw_rlock(&ng_idhash_lock)
198 #define	IDHASH_RUNLOCK()	rw_runlock(&ng_idhash_lock)
199 #define	IDHASH_WLOCK()		rw_wlock(&ng_idhash_lock)
200 #define	IDHASH_WUNLOCK()	rw_wunlock(&ng_idhash_lock)
201 
202 /* Method to find a node.. used twice so do it here */
203 #define NG_IDHASH_FN(ID) ((ID) % (V_ng_ID_hmask + 1))
204 #define NG_IDHASH_FIND(ID, node)					\
205 	do { 								\
206 		rw_assert(&ng_idhash_lock, RA_LOCKED);			\
207 		LIST_FOREACH(node, &V_ng_ID_hash[NG_IDHASH_FN(ID)],	\
208 						nd_idnodes) {		\
209 			if (NG_NODE_IS_VALID(node)			\
210 			&& (NG_NODE_ID(node) == ID)) {			\
211 				break;					\
212 			}						\
213 		}							\
214 	} while (0)
215 
216 static struct rwlock	ng_namehash_lock;
217 #define	NAMEHASH_RLOCK()	rw_rlock(&ng_namehash_lock)
218 #define	NAMEHASH_RUNLOCK()	rw_runlock(&ng_namehash_lock)
219 #define	NAMEHASH_WLOCK()	rw_wlock(&ng_namehash_lock)
220 #define	NAMEHASH_WUNLOCK()	rw_wunlock(&ng_namehash_lock)
221 
222 /* Internal functions */
223 static int	ng_add_hook(node_p node, const char *name, hook_p * hookp);
224 static int	ng_generic_msg(node_p here, item_p item, hook_p lasthook);
225 static ng_ID_t	ng_decodeidname(const char *name);
226 static int	ngb_mod_event(module_t mod, int event, void *data);
227 static void	ng_worklist_add(node_p node);
228 static void	ngthread(void *);
229 static int	ng_apply_item(node_p node, item_p item, int rw);
230 static void	ng_flush_input_queue(node_p node);
231 static node_p	ng_ID2noderef(ng_ID_t ID);
232 static int	ng_con_nodes(item_p item, node_p node, const char *name,
233 		    node_p node2, const char *name2);
234 static int	ng_con_part2(node_p node, item_p item, hook_p hook);
235 static int	ng_con_part3(node_p node, item_p item, hook_p hook);
236 static int	ng_mkpeer(node_p node, const char *name, const char *name2,
237 		    char *type);
238 static void	ng_name_rehash(void);
239 static void	ng_ID_rehash(void);
240 
241 /* Imported, these used to be externally visible, some may go back. */
242 void	ng_destroy_hook(hook_p hook);
243 int	ng_path2noderef(node_p here, const char *path,
244 	node_p *dest, hook_p *lasthook);
245 int	ng_make_node(const char *type, node_p *nodepp);
246 int	ng_path_parse(char *addr, char **node, char **path, char **hook);
247 void	ng_rmnode(node_p node, hook_p dummy1, void *dummy2, int dummy3);
248 void	ng_unname(node_p node);
249 
250 /* Our own netgraph malloc type */
251 MALLOC_DEFINE(M_NETGRAPH, "netgraph", "netgraph structures and ctrl messages");
252 MALLOC_DEFINE(M_NETGRAPH_MSG, "netgraph_msg", "netgraph name storage");
253 static MALLOC_DEFINE(M_NETGRAPH_HOOK, "netgraph_hook",
254     "netgraph hook structures");
255 static MALLOC_DEFINE(M_NETGRAPH_NODE, "netgraph_node",
256     "netgraph node structures");
257 static MALLOC_DEFINE(M_NETGRAPH_ITEM, "netgraph_item",
258     "netgraph item structures");
259 
260 /* Should not be visible outside this file */
261 
262 #define _NG_ALLOC_HOOK(hook) \
263 	hook = malloc(sizeof(*hook), M_NETGRAPH_HOOK, M_NOWAIT | M_ZERO)
264 #define _NG_ALLOC_NODE(node) \
265 	node = malloc(sizeof(*node), M_NETGRAPH_NODE, M_NOWAIT | M_ZERO)
266 
267 #define	NG_QUEUE_LOCK_INIT(n)			\
268 	mtx_init(&(n)->q_mtx, "ng_node", NULL, MTX_DEF)
269 #define	NG_QUEUE_LOCK(n)			\
270 	mtx_lock(&(n)->q_mtx)
271 #define	NG_QUEUE_UNLOCK(n)			\
272 	mtx_unlock(&(n)->q_mtx)
273 #define	NG_WORKLIST_LOCK_INIT()			\
274 	mtx_init(&ng_worklist_mtx, "ng_worklist", NULL, MTX_DEF)
275 #define	NG_WORKLIST_LOCK()			\
276 	mtx_lock(&ng_worklist_mtx)
277 #define	NG_WORKLIST_UNLOCK()			\
278 	mtx_unlock(&ng_worklist_mtx)
279 #define	NG_WORKLIST_SLEEP()			\
280 	mtx_sleep(&ng_worklist, &ng_worklist_mtx, PI_NET, "sleep", 0)
281 #define	NG_WORKLIST_WAKEUP()			\
282 	wakeup_one(&ng_worklist)
283 
284 #ifdef NETGRAPH_DEBUG /*----------------------------------------------*/
285 /*
286  * In debug mode:
287  * In an attempt to help track reference count screwups
288  * we do not free objects back to the malloc system, but keep them
289  * in a local cache where we can examine them and keep information safely
290  * after they have been freed.
291  * We use this scheme for nodes and hooks, and to some extent for items.
292  */
293 static __inline hook_p
294 ng_alloc_hook(void)
295 {
296 	hook_p hook;
297 	SLIST_ENTRY(ng_hook) temp;
298 	mtx_lock(&ng_nodelist_mtx);
299 	hook = LIST_FIRST(&ng_freehooks);
300 	if (hook) {
301 		LIST_REMOVE(hook, hk_hooks);
302 		bcopy(&hook->hk_all, &temp, sizeof(temp));
303 		bzero(hook, sizeof(struct ng_hook));
304 		bcopy(&temp, &hook->hk_all, sizeof(temp));
305 		mtx_unlock(&ng_nodelist_mtx);
306 		hook->hk_magic = HK_MAGIC;
307 	} else {
308 		mtx_unlock(&ng_nodelist_mtx);
309 		_NG_ALLOC_HOOK(hook);
310 		if (hook) {
311 			hook->hk_magic = HK_MAGIC;
312 			mtx_lock(&ng_nodelist_mtx);
313 			SLIST_INSERT_HEAD(&ng_allhooks, hook, hk_all);
314 			mtx_unlock(&ng_nodelist_mtx);
315 		}
316 	}
317 	return (hook);
318 }
319 
320 static __inline node_p
321 ng_alloc_node(void)
322 {
323 	node_p node;
324 	SLIST_ENTRY(ng_node) temp;
325 	mtx_lock(&ng_nodelist_mtx);
326 	node = LIST_FIRST(&ng_freenodes);
327 	if (node) {
328 		LIST_REMOVE(node, nd_nodes);
329 		bcopy(&node->nd_all, &temp, sizeof(temp));
330 		bzero(node, sizeof(struct ng_node));
331 		bcopy(&temp, &node->nd_all, sizeof(temp));
332 		mtx_unlock(&ng_nodelist_mtx);
333 		node->nd_magic = ND_MAGIC;
334 	} else {
335 		mtx_unlock(&ng_nodelist_mtx);
336 		_NG_ALLOC_NODE(node);
337 		if (node) {
338 			node->nd_magic = ND_MAGIC;
339 			mtx_lock(&ng_nodelist_mtx);
340 			SLIST_INSERT_HEAD(&ng_allnodes, node, nd_all);
341 			mtx_unlock(&ng_nodelist_mtx);
342 		}
343 	}
344 	return (node);
345 }
346 
347 #define NG_ALLOC_HOOK(hook) do { (hook) = ng_alloc_hook(); } while (0)
348 #define NG_ALLOC_NODE(node) do { (node) = ng_alloc_node(); } while (0)
349 
350 #define NG_FREE_HOOK(hook)						\
351 	do {								\
352 		mtx_lock(&ng_nodelist_mtx);				\
353 		LIST_INSERT_HEAD(&ng_freehooks, hook, hk_hooks);	\
354 		hook->hk_magic = 0;					\
355 		mtx_unlock(&ng_nodelist_mtx);				\
356 	} while (0)
357 
358 #define NG_FREE_NODE(node)						\
359 	do {								\
360 		mtx_lock(&ng_nodelist_mtx);				\
361 		LIST_INSERT_HEAD(&ng_freenodes, node, nd_nodes);	\
362 		node->nd_magic = 0;					\
363 		mtx_unlock(&ng_nodelist_mtx);				\
364 	} while (0)
365 
366 #else /* NETGRAPH_DEBUG */ /*----------------------------------------------*/
367 
368 #define NG_ALLOC_HOOK(hook) _NG_ALLOC_HOOK(hook)
369 #define NG_ALLOC_NODE(node) _NG_ALLOC_NODE(node)
370 
371 #define NG_FREE_HOOK(hook) do { free((hook), M_NETGRAPH_HOOK); } while (0)
372 #define NG_FREE_NODE(node) do { free((node), M_NETGRAPH_NODE); } while (0)
373 
374 #endif /* NETGRAPH_DEBUG */ /*----------------------------------------------*/
375 
376 /* Set this to kdb_enter("X") to catch all errors as they occur */
377 #ifndef TRAP_ERROR
378 #define TRAP_ERROR()
379 #endif
380 
381 VNET_DEFINE_STATIC(ng_ID_t, nextID) = 1;
382 #define	V_nextID			VNET(nextID)
383 
384 #ifdef INVARIANTS
385 #define CHECK_DATA_MBUF(m)	do {					\
386 		struct mbuf *n;						\
387 		int total;						\
388 									\
389 		M_ASSERTPKTHDR(m);					\
390 		for (total = 0, n = (m); n != NULL; n = n->m_next) {	\
391 			total += n->m_len;				\
392 			if (n->m_nextpkt != NULL)			\
393 				panic("%s: m_nextpkt", __func__);	\
394 		}							\
395 									\
396 		if ((m)->m_pkthdr.len != total) {			\
397 			panic("%s: %d != %d",				\
398 			    __func__, (m)->m_pkthdr.len, total);	\
399 		}							\
400 	} while (0)
401 #else
402 #define CHECK_DATA_MBUF(m)
403 #endif
404 
405 #define ERROUT(x)	do { error = (x); goto done; } while (0)
406 
407 /************************************************************************
408 	Parse type definitions for generic messages
409 ************************************************************************/
410 
411 /* Handy structure parse type defining macro */
412 #define DEFINE_PARSE_STRUCT_TYPE(lo, up, args)				\
413 static const struct ng_parse_struct_field				\
414 	ng_ ## lo ## _type_fields[] = NG_GENERIC_ ## up ## _INFO args;	\
415 static const struct ng_parse_type ng_generic_ ## lo ## _type = {	\
416 	&ng_parse_struct_type,						\
417 	&ng_ ## lo ## _type_fields					\
418 }
419 
420 DEFINE_PARSE_STRUCT_TYPE(mkpeer, MKPEER, ());
421 DEFINE_PARSE_STRUCT_TYPE(connect, CONNECT, ());
422 DEFINE_PARSE_STRUCT_TYPE(name, NAME, ());
423 DEFINE_PARSE_STRUCT_TYPE(rmhook, RMHOOK, ());
424 DEFINE_PARSE_STRUCT_TYPE(nodeinfo, NODEINFO, ());
425 DEFINE_PARSE_STRUCT_TYPE(typeinfo, TYPEINFO, ());
426 DEFINE_PARSE_STRUCT_TYPE(linkinfo, LINKINFO, (&ng_generic_nodeinfo_type));
427 
428 /* Get length of an array when the length is stored as a 32 bit
429    value immediately preceding the array -- as with struct namelist
430    and struct typelist. */
431 static int
432 ng_generic_list_getLength(const struct ng_parse_type *type,
433 	const u_char *start, const u_char *buf)
434 {
435 	return *((const u_int32_t *)(buf - 4));
436 }
437 
438 /* Get length of the array of struct linkinfo inside a struct hooklist */
439 static int
440 ng_generic_linkinfo_getLength(const struct ng_parse_type *type,
441 	const u_char *start, const u_char *buf)
442 {
443 	const struct hooklist *hl = (const struct hooklist *)start;
444 
445 	return hl->nodeinfo.hooks;
446 }
447 
448 /* Array type for a variable length array of struct namelist */
449 static const struct ng_parse_array_info ng_nodeinfoarray_type_info = {
450 	&ng_generic_nodeinfo_type,
451 	&ng_generic_list_getLength
452 };
453 static const struct ng_parse_type ng_generic_nodeinfoarray_type = {
454 	&ng_parse_array_type,
455 	&ng_nodeinfoarray_type_info
456 };
457 
458 /* Array type for a variable length array of struct typelist */
459 static const struct ng_parse_array_info ng_typeinfoarray_type_info = {
460 	&ng_generic_typeinfo_type,
461 	&ng_generic_list_getLength
462 };
463 static const struct ng_parse_type ng_generic_typeinfoarray_type = {
464 	&ng_parse_array_type,
465 	&ng_typeinfoarray_type_info
466 };
467 
468 /* Array type for array of struct linkinfo in struct hooklist */
469 static const struct ng_parse_array_info ng_generic_linkinfo_array_type_info = {
470 	&ng_generic_linkinfo_type,
471 	&ng_generic_linkinfo_getLength
472 };
473 static const struct ng_parse_type ng_generic_linkinfo_array_type = {
474 	&ng_parse_array_type,
475 	&ng_generic_linkinfo_array_type_info
476 };
477 
478 DEFINE_PARSE_STRUCT_TYPE(typelist, TYPELIST, (&ng_generic_typeinfoarray_type));
479 DEFINE_PARSE_STRUCT_TYPE(hooklist, HOOKLIST,
480 	(&ng_generic_nodeinfo_type, &ng_generic_linkinfo_array_type));
481 DEFINE_PARSE_STRUCT_TYPE(listnodes, LISTNODES,
482 	(&ng_generic_nodeinfoarray_type));
483 
484 /* List of commands and how to convert arguments to/from ASCII */
485 static const struct ng_cmdlist ng_generic_cmds[] = {
486 	{
487 	  NGM_GENERIC_COOKIE,
488 	  NGM_SHUTDOWN,
489 	  "shutdown",
490 	  NULL,
491 	  NULL
492 	},
493 	{
494 	  NGM_GENERIC_COOKIE,
495 	  NGM_MKPEER,
496 	  "mkpeer",
497 	  &ng_generic_mkpeer_type,
498 	  NULL
499 	},
500 	{
501 	  NGM_GENERIC_COOKIE,
502 	  NGM_CONNECT,
503 	  "connect",
504 	  &ng_generic_connect_type,
505 	  NULL
506 	},
507 	{
508 	  NGM_GENERIC_COOKIE,
509 	  NGM_NAME,
510 	  "name",
511 	  &ng_generic_name_type,
512 	  NULL
513 	},
514 	{
515 	  NGM_GENERIC_COOKIE,
516 	  NGM_RMHOOK,
517 	  "rmhook",
518 	  &ng_generic_rmhook_type,
519 	  NULL
520 	},
521 	{
522 	  NGM_GENERIC_COOKIE,
523 	  NGM_NODEINFO,
524 	  "nodeinfo",
525 	  NULL,
526 	  &ng_generic_nodeinfo_type
527 	},
528 	{
529 	  NGM_GENERIC_COOKIE,
530 	  NGM_LISTHOOKS,
531 	  "listhooks",
532 	  NULL,
533 	  &ng_generic_hooklist_type
534 	},
535 	{
536 	  NGM_GENERIC_COOKIE,
537 	  NGM_LISTNAMES,
538 	  "listnames",
539 	  NULL,
540 	  &ng_generic_listnodes_type	/* same as NGM_LISTNODES */
541 	},
542 	{
543 	  NGM_GENERIC_COOKIE,
544 	  NGM_LISTNODES,
545 	  "listnodes",
546 	  NULL,
547 	  &ng_generic_listnodes_type
548 	},
549 	{
550 	  NGM_GENERIC_COOKIE,
551 	  NGM_LISTTYPES,
552 	  "listtypes",
553 	  NULL,
554 	  &ng_generic_typelist_type
555 	},
556 	{
557 	  NGM_GENERIC_COOKIE,
558 	  NGM_TEXT_CONFIG,
559 	  "textconfig",
560 	  NULL,
561 	  &ng_parse_string_type
562 	},
563 	{
564 	  NGM_GENERIC_COOKIE,
565 	  NGM_TEXT_STATUS,
566 	  "textstatus",
567 	  NULL,
568 	  &ng_parse_string_type
569 	},
570 	{
571 	  NGM_GENERIC_COOKIE,
572 	  NGM_ASCII2BINARY,
573 	  "ascii2binary",
574 	  &ng_parse_ng_mesg_type,
575 	  &ng_parse_ng_mesg_type
576 	},
577 	{
578 	  NGM_GENERIC_COOKIE,
579 	  NGM_BINARY2ASCII,
580 	  "binary2ascii",
581 	  &ng_parse_ng_mesg_type,
582 	  &ng_parse_ng_mesg_type
583 	},
584 	{ 0 }
585 };
586 
587 /************************************************************************
588 			Node routines
589 ************************************************************************/
590 
591 /*
592  * Instantiate a node of the requested type
593  */
594 int
595 ng_make_node(const char *typename, node_p *nodepp)
596 {
597 	struct ng_type *type;
598 	int	error;
599 
600 	/* Check that the type makes sense */
601 	if (typename == NULL) {
602 		TRAP_ERROR();
603 		return (EINVAL);
604 	}
605 
606 	/* Locate the node type. If we fail we return. Do not try to load
607 	 * module.
608 	 */
609 	if ((type = ng_findtype(typename)) == NULL)
610 		return (ENXIO);
611 
612 	/*
613 	 * If we have a constructor, then make the node and
614 	 * call the constructor to do type specific initialisation.
615 	 */
616 	if (type->constructor != NULL) {
617 		if ((error = ng_make_node_common(type, nodepp)) == 0) {
618 			if ((error = ((*type->constructor)(*nodepp))) != 0) {
619 				NG_NODE_UNREF(*nodepp);
620 			}
621 		}
622 	} else {
623 		/*
624 		 * Node has no constructor. We cannot ask for one
625 		 * to be made. It must be brought into existence by
626 		 * some external agency. The external agency should
627 		 * call ng_make_node_common() directly to get the
628 		 * netgraph part initialised.
629 		 */
630 		TRAP_ERROR();
631 		error = EINVAL;
632 	}
633 	return (error);
634 }
635 
636 /*
637  * Generic node creation. Called by node initialisation for externally
638  * instantiated nodes (e.g. hardware, sockets, etc ).
639  * The returned node has a reference count of 1.
640  */
641 int
642 ng_make_node_common(struct ng_type *type, node_p *nodepp)
643 {
644 	node_p node;
645 
646 	/* Require the node type to have been already installed */
647 	if (ng_findtype(type->name) == NULL) {
648 		TRAP_ERROR();
649 		return (EINVAL);
650 	}
651 
652 	/* Make a node and try attach it to the type */
653 	NG_ALLOC_NODE(node);
654 	if (node == NULL) {
655 		TRAP_ERROR();
656 		return (ENOMEM);
657 	}
658 	node->nd_type = type;
659 #ifdef VIMAGE
660 	node->nd_vnet = curvnet;
661 #endif
662 	NG_NODE_REF(node);				/* note reference */
663 	type->refs++;
664 
665 	NG_QUEUE_LOCK_INIT(&node->nd_input_queue);
666 	STAILQ_INIT(&node->nd_input_queue.queue);
667 	node->nd_input_queue.q_flags = 0;
668 
669 	/* Initialize hook list for new node */
670 	LIST_INIT(&node->nd_hooks);
671 
672 	/* Get an ID and put us in the hash chain. */
673 	IDHASH_WLOCK();
674 	for (;;) { /* wrap protection, even if silly */
675 		node_p node2 = NULL;
676 		node->nd_ID = V_nextID++; /* 137/sec for 1 year before wrap */
677 
678 		/* Is there a problem with the new number? */
679 		NG_IDHASH_FIND(node->nd_ID, node2); /* already taken? */
680 		if ((node->nd_ID != 0) && (node2 == NULL)) {
681 			break;
682 		}
683 	}
684 	V_ng_nodes++;
685 	if (V_ng_nodes * 2 > V_ng_ID_hmask)
686 		ng_ID_rehash();
687 	LIST_INSERT_HEAD(&V_ng_ID_hash[NG_IDHASH_FN(node->nd_ID)], node,
688 	    nd_idnodes);
689 	IDHASH_WUNLOCK();
690 
691 	/* Done */
692 	*nodepp = node;
693 	return (0);
694 }
695 
696 /*
697  * Forceably start the shutdown process on a node. Either call
698  * its shutdown method, or do the default shutdown if there is
699  * no type-specific method.
700  *
701  * We can only be called from a shutdown message, so we know we have
702  * a writer lock, and therefore exclusive access. It also means
703  * that we should not be on the work queue, but we check anyhow.
704  *
705  * Persistent node types must have a type-specific method which
706  * allocates a new node in which case, this one is irretrievably going away,
707  * or cleans up anything it needs, and just makes the node valid again,
708  * in which case we allow the node to survive.
709  *
710  * XXX We need to think of how to tell a persistent node that we
711  * REALLY need to go away because the hardware has gone or we
712  * are rebooting.... etc.
713  */
714 void
715 ng_rmnode(node_p node, hook_p dummy1, void *dummy2, int dummy3)
716 {
717 	hook_p hook;
718 
719 	/* Check if it's already shutting down */
720 	if ((node->nd_flags & NGF_CLOSING) != 0)
721 		return;
722 
723 	if (node == &ng_deadnode) {
724 		printf ("shutdown called on deadnode\n");
725 		return;
726 	}
727 
728 	/* Add an extra reference so it doesn't go away during this */
729 	NG_NODE_REF(node);
730 
731 	/*
732 	 * Mark it invalid so any newcomers know not to try use it
733 	 * Also add our own mark so we can't recurse
734 	 * note that NGF_INVALID does not do this as it's also set during
735 	 * creation
736 	 */
737 	node->nd_flags |= NGF_INVALID|NGF_CLOSING;
738 
739 	/* If node has its pre-shutdown method, then call it first*/
740 	if (node->nd_type && node->nd_type->close)
741 		(*node->nd_type->close)(node);
742 
743 	/* Notify all remaining connected nodes to disconnect */
744 	while ((hook = LIST_FIRST(&node->nd_hooks)) != NULL)
745 		ng_destroy_hook(hook);
746 
747 	/*
748 	 * Drain the input queue forceably.
749 	 * it has no hooks so what's it going to do, bleed on someone?
750 	 * Theoretically we came here from a queue entry that was added
751 	 * Just before the queue was closed, so it should be empty anyway.
752 	 * Also removes us from worklist if needed.
753 	 */
754 	ng_flush_input_queue(node);
755 
756 	/* Ask the type if it has anything to do in this case */
757 	if (node->nd_type && node->nd_type->shutdown) {
758 		(*node->nd_type->shutdown)(node);
759 		if (NG_NODE_IS_VALID(node)) {
760 			/*
761 			 * Well, blow me down if the node code hasn't declared
762 			 * that it doesn't want to die.
763 			 * Presumably it is a persistent node.
764 			 * If we REALLY want it to go away,
765 			 *  e.g. hardware going away,
766 			 * Our caller should set NGF_REALLY_DIE in nd_flags.
767 			 */
768 			node->nd_flags &= ~(NGF_INVALID|NGF_CLOSING);
769 			NG_NODE_UNREF(node); /* Assume they still have theirs */
770 			return;
771 		}
772 	} else {				/* do the default thing */
773 		NG_NODE_UNREF(node);
774 	}
775 
776 	ng_unname(node); /* basically a NOP these days */
777 
778 	/*
779 	 * Remove extra reference, possibly the last
780 	 * Possible other holders of references may include
781 	 * timeout callouts, but theoretically the node's supposed to
782 	 * have cancelled them. Possibly hardware dependencies may
783 	 * force a driver to 'linger' with a reference.
784 	 */
785 	NG_NODE_UNREF(node);
786 }
787 
788 /*
789  * Remove a reference to the node, possibly the last.
790  * deadnode always acts as it were the last.
791  */
792 void
793 ng_unref_node(node_p node)
794 {
795 
796 	if (node == &ng_deadnode)
797 		return;
798 
799 	CURVNET_SET(node->nd_vnet);
800 
801 	if (refcount_release(&node->nd_refs)) { /* we were the last */
802 
803 		node->nd_type->refs--; /* XXX maybe should get types lock? */
804 		NAMEHASH_WLOCK();
805 		if (NG_NODE_HAS_NAME(node)) {
806 			V_ng_named_nodes--;
807 			LIST_REMOVE(node, nd_nodes);
808 		}
809 		NAMEHASH_WUNLOCK();
810 
811 		IDHASH_WLOCK();
812 		V_ng_nodes--;
813 		LIST_REMOVE(node, nd_idnodes);
814 		IDHASH_WUNLOCK();
815 
816 		mtx_destroy(&node->nd_input_queue.q_mtx);
817 		NG_FREE_NODE(node);
818 	}
819 	CURVNET_RESTORE();
820 }
821 
822 /************************************************************************
823 			Node ID handling
824 ************************************************************************/
825 static node_p
826 ng_ID2noderef(ng_ID_t ID)
827 {
828 	node_p node;
829 
830 	IDHASH_RLOCK();
831 	NG_IDHASH_FIND(ID, node);
832 	if (node)
833 		NG_NODE_REF(node);
834 	IDHASH_RUNLOCK();
835 	return(node);
836 }
837 
838 ng_ID_t
839 ng_node2ID(node_cp node)
840 {
841 	return (node ? NG_NODE_ID(node) : 0);
842 }
843 
844 /************************************************************************
845 			Node name handling
846 ************************************************************************/
847 
848 /*
849  * Assign a node a name.
850  */
851 int
852 ng_name_node(node_p node, const char *name)
853 {
854 	uint32_t hash;
855 	node_p node2;
856 	int i;
857 
858 	/* Rename without change is a noop */
859 	if (strcmp(NG_NODE_NAME(node), name) == 0)
860 		return (0);
861 
862 	/* Check the name is valid */
863 	for (i = 0; i < NG_NODESIZ; i++) {
864 		if (name[i] == '\0' || name[i] == '.' || name[i] == ':')
865 			break;
866 	}
867 	if (i == 0 || name[i] != '\0') {
868 		TRAP_ERROR();
869 		return (EINVAL);
870 	}
871 	if (ng_decodeidname(name) != 0) { /* valid IDs not allowed here */
872 		TRAP_ERROR();
873 		return (EINVAL);
874 	}
875 
876 	NAMEHASH_WLOCK();
877 	if (V_ng_named_nodes * 2 > V_ng_name_hmask)
878 		ng_name_rehash();
879 
880 	hash = hash32_str(name, HASHINIT) & V_ng_name_hmask;
881 	/* Check the name isn't already being used. */
882 	LIST_FOREACH(node2, &V_ng_name_hash[hash], nd_nodes)
883 		if (NG_NODE_IS_VALID(node2) &&
884 		    (strcmp(NG_NODE_NAME(node2), name) == 0)) {
885 			NAMEHASH_WUNLOCK();
886 			return (EADDRINUSE);
887 		}
888 
889 	if (NG_NODE_HAS_NAME(node))
890 		LIST_REMOVE(node, nd_nodes);
891 	else
892 		V_ng_named_nodes++;
893 	/* Copy it. */
894 	strlcpy(NG_NODE_NAME(node), name, NG_NODESIZ);
895 	/* Update name hash. */
896 	LIST_INSERT_HEAD(&V_ng_name_hash[hash], node, nd_nodes);
897 	NAMEHASH_WUNLOCK();
898 
899 	return (0);
900 }
901 
902 /*
903  * Find a node by absolute name. The name should NOT end with ':'
904  * The name "." means "this node" and "[xxx]" means "the node
905  * with ID (ie, at address) xxx".
906  *
907  * Returns the node if found, else NULL.
908  * Eventually should add something faster than a sequential search.
909  * Note it acquires a reference on the node so you can be sure it's still
910  * there.
911  */
912 node_p
913 ng_name2noderef(node_p here, const char *name)
914 {
915 	node_p node;
916 	ng_ID_t temp;
917 	int	hash;
918 
919 	/* "." means "this node" */
920 	if (strcmp(name, ".") == 0) {
921 		NG_NODE_REF(here);
922 		return(here);
923 	}
924 
925 	/* Check for name-by-ID */
926 	if ((temp = ng_decodeidname(name)) != 0) {
927 		return (ng_ID2noderef(temp));
928 	}
929 
930 	/* Find node by name. */
931 	hash = hash32_str(name, HASHINIT) & V_ng_name_hmask;
932 	NAMEHASH_RLOCK();
933 	LIST_FOREACH(node, &V_ng_name_hash[hash], nd_nodes)
934 		if (NG_NODE_IS_VALID(node) &&
935 		    (strcmp(NG_NODE_NAME(node), name) == 0)) {
936 			NG_NODE_REF(node);
937 			break;
938 		}
939 	NAMEHASH_RUNLOCK();
940 
941 	return (node);
942 }
943 
944 /*
945  * Decode an ID name, eg. "[f03034de]". Returns 0 if the
946  * string is not valid, otherwise returns the value.
947  */
948 static ng_ID_t
949 ng_decodeidname(const char *name)
950 {
951 	const int len = strlen(name);
952 	char *eptr;
953 	u_long val;
954 
955 	/* Check for proper length, brackets, no leading junk */
956 	if ((len < 3) || (name[0] != '[') || (name[len - 1] != ']') ||
957 	    (!isxdigit(name[1])))
958 		return ((ng_ID_t)0);
959 
960 	/* Decode number */
961 	val = strtoul(name + 1, &eptr, 16);
962 	if ((eptr - name != len - 1) || (val == ULONG_MAX) || (val == 0))
963 		return ((ng_ID_t)0);
964 
965 	return ((ng_ID_t)val);
966 }
967 
968 /*
969  * Remove a name from a node. This should only be called
970  * when shutting down and removing the node.
971  */
972 void
973 ng_unname(node_p node)
974 {
975 }
976 
977 /*
978  * Allocate a bigger name hash.
979  */
980 static void
981 ng_name_rehash()
982 {
983 	struct nodehash *new;
984 	uint32_t hash;
985 	u_long hmask;
986 	node_p node, node2;
987 	int i;
988 
989 	new = hashinit_flags((V_ng_name_hmask + 1) * 2, M_NETGRAPH_NODE, &hmask,
990 	    HASH_NOWAIT);
991 	if (new == NULL)
992 		return;
993 
994 	for (i = 0; i <= V_ng_name_hmask; i++)
995 		LIST_FOREACH_SAFE(node, &V_ng_name_hash[i], nd_nodes, node2) {
996 #ifdef INVARIANTS
997 			LIST_REMOVE(node, nd_nodes);
998 #endif
999 			hash = hash32_str(NG_NODE_NAME(node), HASHINIT) & hmask;
1000 			LIST_INSERT_HEAD(&new[hash], node, nd_nodes);
1001 		}
1002 
1003 	hashdestroy(V_ng_name_hash, M_NETGRAPH_NODE, V_ng_name_hmask);
1004 	V_ng_name_hash = new;
1005 	V_ng_name_hmask = hmask;
1006 }
1007 
1008 /*
1009  * Allocate a bigger ID hash.
1010  */
1011 static void
1012 ng_ID_rehash()
1013 {
1014 	struct nodehash *new;
1015 	uint32_t hash;
1016 	u_long hmask;
1017 	node_p node, node2;
1018 	int i;
1019 
1020 	new = hashinit_flags((V_ng_ID_hmask + 1) * 2, M_NETGRAPH_NODE, &hmask,
1021 	    HASH_NOWAIT);
1022 	if (new == NULL)
1023 		return;
1024 
1025 	for (i = 0; i <= V_ng_ID_hmask; i++)
1026 		LIST_FOREACH_SAFE(node, &V_ng_ID_hash[i], nd_idnodes, node2) {
1027 #ifdef INVARIANTS
1028 			LIST_REMOVE(node, nd_idnodes);
1029 #endif
1030 			hash = (node->nd_ID % (hmask + 1));
1031 			LIST_INSERT_HEAD(&new[hash], node, nd_idnodes);
1032 		}
1033 
1034 	hashdestroy(V_ng_ID_hash, M_NETGRAPH_NODE, V_ng_name_hmask);
1035 	V_ng_ID_hash = new;
1036 	V_ng_ID_hmask = hmask;
1037 }
1038 
1039 /************************************************************************
1040 			Hook routines
1041  Names are not optional. Hooks are always connected, except for a
1042  brief moment within these routines. On invalidation or during creation
1043  they are connected to the 'dead' hook.
1044 ************************************************************************/
1045 
1046 /*
1047  * Remove a hook reference
1048  */
1049 void
1050 ng_unref_hook(hook_p hook)
1051 {
1052 
1053 	if (hook == &ng_deadhook)
1054 		return;
1055 
1056 	if (refcount_release(&hook->hk_refs)) { /* we were the last */
1057 		if (_NG_HOOK_NODE(hook)) /* it'll probably be ng_deadnode */
1058 			_NG_NODE_UNREF((_NG_HOOK_NODE(hook)));
1059 		NG_FREE_HOOK(hook);
1060 	}
1061 }
1062 
1063 /*
1064  * Add an unconnected hook to a node. Only used internally.
1065  * Assumes node is locked. (XXX not yet true )
1066  */
1067 static int
1068 ng_add_hook(node_p node, const char *name, hook_p *hookp)
1069 {
1070 	hook_p hook;
1071 	int error = 0;
1072 
1073 	/* Check that the given name is good */
1074 	if (name == NULL) {
1075 		TRAP_ERROR();
1076 		return (EINVAL);
1077 	}
1078 	if (ng_findhook(node, name) != NULL) {
1079 		TRAP_ERROR();
1080 		return (EEXIST);
1081 	}
1082 
1083 	/* Allocate the hook and link it up */
1084 	NG_ALLOC_HOOK(hook);
1085 	if (hook == NULL) {
1086 		TRAP_ERROR();
1087 		return (ENOMEM);
1088 	}
1089 	hook->hk_refs = 1;		/* add a reference for us to return */
1090 	hook->hk_flags = HK_INVALID;
1091 	hook->hk_peer = &ng_deadhook;	/* start off this way */
1092 	hook->hk_node = node;
1093 	NG_NODE_REF(node);		/* each hook counts as a reference */
1094 
1095 	/* Set hook name */
1096 	strlcpy(NG_HOOK_NAME(hook), name, NG_HOOKSIZ);
1097 
1098 	/*
1099 	 * Check if the node type code has something to say about it
1100 	 * If it fails, the unref of the hook will also unref the node.
1101 	 */
1102 	if (node->nd_type->newhook != NULL) {
1103 		if ((error = (*node->nd_type->newhook)(node, hook, name))) {
1104 			NG_HOOK_UNREF(hook);	/* this frees the hook */
1105 			return (error);
1106 		}
1107 	}
1108 	/*
1109 	 * The 'type' agrees so far, so go ahead and link it in.
1110 	 * We'll ask again later when we actually connect the hooks.
1111 	 */
1112 	LIST_INSERT_HEAD(&node->nd_hooks, hook, hk_hooks);
1113 	node->nd_numhooks++;
1114 	NG_HOOK_REF(hook);	/* one for the node */
1115 
1116 	if (hookp)
1117 		*hookp = hook;
1118 	return (0);
1119 }
1120 
1121 /*
1122  * Find a hook
1123  *
1124  * Node types may supply their own optimized routines for finding
1125  * hooks.  If none is supplied, we just do a linear search.
1126  * XXX Possibly we should add a reference to the hook?
1127  */
1128 hook_p
1129 ng_findhook(node_p node, const char *name)
1130 {
1131 	hook_p hook;
1132 
1133 	if (node->nd_type->findhook != NULL)
1134 		return (*node->nd_type->findhook)(node, name);
1135 	LIST_FOREACH(hook, &node->nd_hooks, hk_hooks) {
1136 		if (NG_HOOK_IS_VALID(hook) &&
1137 		    (strcmp(NG_HOOK_NAME(hook), name) == 0))
1138 			return (hook);
1139 	}
1140 	return (NULL);
1141 }
1142 
1143 /*
1144  * Destroy a hook
1145  *
1146  * As hooks are always attached, this really destroys two hooks.
1147  * The one given, and the one attached to it. Disconnect the hooks
1148  * from each other first. We reconnect the peer hook to the 'dead'
1149  * hook so that it can still exist after we depart. We then
1150  * send the peer its own destroy message. This ensures that we only
1151  * interact with the peer's structures when it is locked processing that
1152  * message. We hold a reference to the peer hook so we are guaranteed that
1153  * the peer hook and node are still going to exist until
1154  * we are finished there as the hook holds a ref on the node.
1155  * We run this same code again on the peer hook, but that time it is already
1156  * attached to the 'dead' hook.
1157  *
1158  * This routine is called at all stages of hook creation
1159  * on error detection and must be able to handle any such stage.
1160  */
1161 void
1162 ng_destroy_hook(hook_p hook)
1163 {
1164 	hook_p peer;
1165 	node_p node;
1166 
1167 	if (hook == &ng_deadhook) {	/* better safe than sorry */
1168 		printf("ng_destroy_hook called on deadhook\n");
1169 		return;
1170 	}
1171 
1172 	/*
1173 	 * Protect divorce process with mutex, to avoid races on
1174 	 * simultaneous disconnect.
1175 	 */
1176 	TOPOLOGY_WLOCK();
1177 
1178 	hook->hk_flags |= HK_INVALID;
1179 
1180 	peer = NG_HOOK_PEER(hook);
1181 	node = NG_HOOK_NODE(hook);
1182 
1183 	if (peer && (peer != &ng_deadhook)) {
1184 		/*
1185 		 * Set the peer to point to ng_deadhook
1186 		 * from this moment on we are effectively independent it.
1187 		 * send it an rmhook message of its own.
1188 		 */
1189 		peer->hk_peer = &ng_deadhook;	/* They no longer know us */
1190 		hook->hk_peer = &ng_deadhook;	/* Nor us, them */
1191 		if (NG_HOOK_NODE(peer) == &ng_deadnode) {
1192 			/*
1193 			 * If it's already divorced from a node,
1194 			 * just free it.
1195 			 */
1196 			TOPOLOGY_WUNLOCK();
1197 		} else {
1198 			TOPOLOGY_WUNLOCK();
1199 			ng_rmhook_self(peer); 	/* Send it a surprise */
1200 		}
1201 		NG_HOOK_UNREF(peer);		/* account for peer link */
1202 		NG_HOOK_UNREF(hook);		/* account for peer link */
1203 	} else
1204 		TOPOLOGY_WUNLOCK();
1205 
1206 	TOPOLOGY_NOTOWNED();
1207 
1208 	/*
1209 	 * Remove the hook from the node's list to avoid possible recursion
1210 	 * in case the disconnection results in node shutdown.
1211 	 */
1212 	if (node == &ng_deadnode) { /* happens if called from ng_con_nodes() */
1213 		return;
1214 	}
1215 	LIST_REMOVE(hook, hk_hooks);
1216 	node->nd_numhooks--;
1217 	if (node->nd_type->disconnect) {
1218 		/*
1219 		 * The type handler may elect to destroy the node so don't
1220 		 * trust its existence after this point. (except
1221 		 * that we still hold a reference on it. (which we
1222 		 * inherrited from the hook we are destroying)
1223 		 */
1224 		(*node->nd_type->disconnect) (hook);
1225 	}
1226 
1227 	/*
1228 	 * Note that because we will point to ng_deadnode, the original node
1229 	 * is not decremented automatically so we do that manually.
1230 	 */
1231 	_NG_HOOK_NODE(hook) = &ng_deadnode;
1232 	NG_NODE_UNREF(node);	/* We no longer point to it so adjust count */
1233 	NG_HOOK_UNREF(hook);	/* Account for linkage (in list) to node */
1234 }
1235 
1236 /*
1237  * Take two hooks on a node and merge the connection so that the given node
1238  * is effectively bypassed.
1239  */
1240 int
1241 ng_bypass(hook_p hook1, hook_p hook2)
1242 {
1243 	if (hook1->hk_node != hook2->hk_node) {
1244 		TRAP_ERROR();
1245 		return (EINVAL);
1246 	}
1247 	TOPOLOGY_WLOCK();
1248 	if (NG_HOOK_NOT_VALID(hook1) || NG_HOOK_NOT_VALID(hook2)) {
1249 		TOPOLOGY_WUNLOCK();
1250 		return (EINVAL);
1251 	}
1252 	hook1->hk_peer->hk_peer = hook2->hk_peer;
1253 	hook2->hk_peer->hk_peer = hook1->hk_peer;
1254 
1255 	hook1->hk_peer = &ng_deadhook;
1256 	hook2->hk_peer = &ng_deadhook;
1257 	TOPOLOGY_WUNLOCK();
1258 
1259 	NG_HOOK_UNREF(hook1);
1260 	NG_HOOK_UNREF(hook2);
1261 
1262 	/* XXX If we ever cache methods on hooks update them as well */
1263 	ng_destroy_hook(hook1);
1264 	ng_destroy_hook(hook2);
1265 	return (0);
1266 }
1267 
1268 /*
1269  * Install a new netgraph type
1270  */
1271 int
1272 ng_newtype(struct ng_type *tp)
1273 {
1274 	const size_t namelen = strlen(tp->name);
1275 
1276 	/* Check version and type name fields */
1277 	if ((tp->version != NG_ABI_VERSION) || (namelen == 0) ||
1278 	    (namelen >= NG_TYPESIZ)) {
1279 		TRAP_ERROR();
1280 		if (tp->version != NG_ABI_VERSION) {
1281 			printf("Netgraph: Node type rejected. ABI mismatch. "
1282 			    "Suggest recompile\n");
1283 		}
1284 		return (EINVAL);
1285 	}
1286 
1287 	/* Check for name collision */
1288 	if (ng_findtype(tp->name) != NULL) {
1289 		TRAP_ERROR();
1290 		return (EEXIST);
1291 	}
1292 
1293 	/* Link in new type */
1294 	TYPELIST_WLOCK();
1295 	LIST_INSERT_HEAD(&ng_typelist, tp, types);
1296 	tp->refs = 1;	/* first ref is linked list */
1297 	TYPELIST_WUNLOCK();
1298 	return (0);
1299 }
1300 
1301 /*
1302  * unlink a netgraph type
1303  * If no examples exist
1304  */
1305 int
1306 ng_rmtype(struct ng_type *tp)
1307 {
1308 	/* Check for name collision */
1309 	if (tp->refs != 1) {
1310 		TRAP_ERROR();
1311 		return (EBUSY);
1312 	}
1313 
1314 	/* Unlink type */
1315 	TYPELIST_WLOCK();
1316 	LIST_REMOVE(tp, types);
1317 	TYPELIST_WUNLOCK();
1318 	return (0);
1319 }
1320 
1321 /*
1322  * Look for a type of the name given
1323  */
1324 struct ng_type *
1325 ng_findtype(const char *typename)
1326 {
1327 	struct ng_type *type;
1328 
1329 	TYPELIST_RLOCK();
1330 	LIST_FOREACH(type, &ng_typelist, types) {
1331 		if (strcmp(type->name, typename) == 0)
1332 			break;
1333 	}
1334 	TYPELIST_RUNLOCK();
1335 	return (type);
1336 }
1337 
1338 /************************************************************************
1339 			Composite routines
1340 ************************************************************************/
1341 /*
1342  * Connect two nodes using the specified hooks, using queued functions.
1343  */
1344 static int
1345 ng_con_part3(node_p node, item_p item, hook_p hook)
1346 {
1347 	int	error = 0;
1348 
1349 	/*
1350 	 * When we run, we know that the node 'node' is locked for us.
1351 	 * Our caller has a reference on the hook.
1352 	 * Our caller has a reference on the node.
1353 	 * (In this case our caller is ng_apply_item() ).
1354 	 * The peer hook has a reference on the hook.
1355 	 * We are all set up except for the final call to the node, and
1356 	 * the clearing of the INVALID flag.
1357 	 */
1358 	if (NG_HOOK_NODE(hook) == &ng_deadnode) {
1359 		/*
1360 		 * The node must have been freed again since we last visited
1361 		 * here. ng_destry_hook() has this effect but nothing else does.
1362 		 * We should just release our references and
1363 		 * free anything we can think of.
1364 		 * Since we know it's been destroyed, and it's our caller
1365 		 * that holds the references, just return.
1366 		 */
1367 		ERROUT(ENOENT);
1368 	}
1369 	if (hook->hk_node->nd_type->connect) {
1370 		if ((error = (*hook->hk_node->nd_type->connect) (hook))) {
1371 			ng_destroy_hook(hook);	/* also zaps peer */
1372 			printf("failed in ng_con_part3()\n");
1373 			ERROUT(error);
1374 		}
1375 	}
1376 	/*
1377 	 *  XXX this is wrong for SMP. Possibly we need
1378 	 * to separate out 'create' and 'invalid' flags.
1379 	 * should only set flags on hooks we have locked under our node.
1380 	 */
1381 	hook->hk_flags &= ~HK_INVALID;
1382 done:
1383 	NG_FREE_ITEM(item);
1384 	return (error);
1385 }
1386 
1387 static int
1388 ng_con_part2(node_p node, item_p item, hook_p hook)
1389 {
1390 	hook_p	peer;
1391 	int	error = 0;
1392 
1393 	/*
1394 	 * When we run, we know that the node 'node' is locked for us.
1395 	 * Our caller has a reference on the hook.
1396 	 * Our caller has a reference on the node.
1397 	 * (In this case our caller is ng_apply_item() ).
1398 	 * The peer hook has a reference on the hook.
1399 	 * our node pointer points to the 'dead' node.
1400 	 * First check the hook name is unique.
1401 	 * Should not happen because we checked before queueing this.
1402 	 */
1403 	if (ng_findhook(node, NG_HOOK_NAME(hook)) != NULL) {
1404 		TRAP_ERROR();
1405 		ng_destroy_hook(hook); /* should destroy peer too */
1406 		printf("failed in ng_con_part2()\n");
1407 		ERROUT(EEXIST);
1408 	}
1409 	/*
1410 	 * Check if the node type code has something to say about it
1411 	 * If it fails, the unref of the hook will also unref the attached node,
1412 	 * however since that node is 'ng_deadnode' this will do nothing.
1413 	 * The peer hook will also be destroyed.
1414 	 */
1415 	if (node->nd_type->newhook != NULL) {
1416 		if ((error = (*node->nd_type->newhook)(node, hook,
1417 		    hook->hk_name))) {
1418 			ng_destroy_hook(hook); /* should destroy peer too */
1419 			printf("failed in ng_con_part2()\n");
1420 			ERROUT(error);
1421 		}
1422 	}
1423 
1424 	/*
1425 	 * The 'type' agrees so far, so go ahead and link it in.
1426 	 * We'll ask again later when we actually connect the hooks.
1427 	 */
1428 	hook->hk_node = node;		/* just overwrite ng_deadnode */
1429 	NG_NODE_REF(node);		/* each hook counts as a reference */
1430 	LIST_INSERT_HEAD(&node->nd_hooks, hook, hk_hooks);
1431 	node->nd_numhooks++;
1432 	NG_HOOK_REF(hook);	/* one for the node */
1433 
1434 	/*
1435 	 * We now have a symmetrical situation, where both hooks have been
1436 	 * linked to their nodes, the newhook methods have been called
1437 	 * And the references are all correct. The hooks are still marked
1438 	 * as invalid, as we have not called the 'connect' methods
1439 	 * yet.
1440 	 * We can call the local one immediately as we have the
1441 	 * node locked, but we need to queue the remote one.
1442 	 */
1443 	if (hook->hk_node->nd_type->connect) {
1444 		if ((error = (*hook->hk_node->nd_type->connect) (hook))) {
1445 			ng_destroy_hook(hook);	/* also zaps peer */
1446 			printf("failed in ng_con_part2(A)\n");
1447 			ERROUT(error);
1448 		}
1449 	}
1450 
1451 	/*
1452 	 * Acquire topo mutex to avoid race with ng_destroy_hook().
1453 	 */
1454 	TOPOLOGY_RLOCK();
1455 	peer = hook->hk_peer;
1456 	if (peer == &ng_deadhook) {
1457 		TOPOLOGY_RUNLOCK();
1458 		printf("failed in ng_con_part2(B)\n");
1459 		ng_destroy_hook(hook);
1460 		ERROUT(ENOENT);
1461 	}
1462 	TOPOLOGY_RUNLOCK();
1463 
1464 	if ((error = ng_send_fn2(peer->hk_node, peer, item, &ng_con_part3,
1465 	    NULL, 0, NG_REUSE_ITEM))) {
1466 		printf("failed in ng_con_part2(C)\n");
1467 		ng_destroy_hook(hook);	/* also zaps peer */
1468 		return (error);		/* item was consumed. */
1469 	}
1470 	hook->hk_flags &= ~HK_INVALID; /* need both to be able to work */
1471 	return (0);			/* item was consumed. */
1472 done:
1473 	NG_FREE_ITEM(item);
1474 	return (error);
1475 }
1476 
1477 /*
1478  * Connect this node with another node. We assume that this node is
1479  * currently locked, as we are only called from an NGM_CONNECT message.
1480  */
1481 static int
1482 ng_con_nodes(item_p item, node_p node, const char *name,
1483     node_p node2, const char *name2)
1484 {
1485 	int	error;
1486 	hook_p	hook;
1487 	hook_p	hook2;
1488 
1489 	if (ng_findhook(node2, name2) != NULL) {
1490 		return(EEXIST);
1491 	}
1492 	if ((error = ng_add_hook(node, name, &hook)))  /* gives us a ref */
1493 		return (error);
1494 	/* Allocate the other hook and link it up */
1495 	NG_ALLOC_HOOK(hook2);
1496 	if (hook2 == NULL) {
1497 		TRAP_ERROR();
1498 		ng_destroy_hook(hook);	/* XXX check ref counts so far */
1499 		NG_HOOK_UNREF(hook);	/* including our ref */
1500 		return (ENOMEM);
1501 	}
1502 	hook2->hk_refs = 1;		/* start with a reference for us. */
1503 	hook2->hk_flags = HK_INVALID;
1504 	hook2->hk_peer = hook;		/* Link the two together */
1505 	hook->hk_peer = hook2;
1506 	NG_HOOK_REF(hook);		/* Add a ref for the peer to each*/
1507 	NG_HOOK_REF(hook2);
1508 	hook2->hk_node = &ng_deadnode;
1509 	strlcpy(NG_HOOK_NAME(hook2), name2, NG_HOOKSIZ);
1510 
1511 	/*
1512 	 * Queue the function above.
1513 	 * Procesing continues in that function in the lock context of
1514 	 * the other node.
1515 	 */
1516 	if ((error = ng_send_fn2(node2, hook2, item, &ng_con_part2, NULL, 0,
1517 	    NG_NOFLAGS))) {
1518 		printf("failed in ng_con_nodes(): %d\n", error);
1519 		ng_destroy_hook(hook);	/* also zaps peer */
1520 	}
1521 
1522 	NG_HOOK_UNREF(hook);		/* Let each hook go if it wants to */
1523 	NG_HOOK_UNREF(hook2);
1524 	return (error);
1525 }
1526 
1527 /*
1528  * Make a peer and connect.
1529  * We assume that the local node is locked.
1530  * The new node probably doesn't need a lock until
1531  * it has a hook, because it cannot really have any work until then,
1532  * but we should think about it a bit more.
1533  *
1534  * The problem may come if the other node also fires up
1535  * some hardware or a timer or some other source of activation,
1536  * also it may already get a command msg via it's ID.
1537  *
1538  * We could use the same method as ng_con_nodes() but we'd have
1539  * to add ability to remove the node when failing. (Not hard, just
1540  * make arg1 point to the node to remove).
1541  * Unless of course we just ignore failure to connect and leave
1542  * an unconnected node?
1543  */
1544 static int
1545 ng_mkpeer(node_p node, const char *name, const char *name2, char *type)
1546 {
1547 	node_p	node2;
1548 	hook_p	hook1, hook2;
1549 	int	error;
1550 
1551 	if ((error = ng_make_node(type, &node2))) {
1552 		return (error);
1553 	}
1554 
1555 	if ((error = ng_add_hook(node, name, &hook1))) { /* gives us a ref */
1556 		ng_rmnode(node2, NULL, NULL, 0);
1557 		return (error);
1558 	}
1559 
1560 	if ((error = ng_add_hook(node2, name2, &hook2))) {
1561 		ng_rmnode(node2, NULL, NULL, 0);
1562 		ng_destroy_hook(hook1);
1563 		NG_HOOK_UNREF(hook1);
1564 		return (error);
1565 	}
1566 
1567 	/*
1568 	 * Actually link the two hooks together.
1569 	 */
1570 	hook1->hk_peer = hook2;
1571 	hook2->hk_peer = hook1;
1572 
1573 	/* Each hook is referenced by the other */
1574 	NG_HOOK_REF(hook1);
1575 	NG_HOOK_REF(hook2);
1576 
1577 	/* Give each node the opportunity to veto the pending connection */
1578 	if (hook1->hk_node->nd_type->connect) {
1579 		error = (*hook1->hk_node->nd_type->connect) (hook1);
1580 	}
1581 
1582 	if ((error == 0) && hook2->hk_node->nd_type->connect) {
1583 		error = (*hook2->hk_node->nd_type->connect) (hook2);
1584 	}
1585 
1586 	/*
1587 	 * drop the references we were holding on the two hooks.
1588 	 */
1589 	if (error) {
1590 		ng_destroy_hook(hook2);	/* also zaps hook1 */
1591 		ng_rmnode(node2, NULL, NULL, 0);
1592 	} else {
1593 		/* As a last act, allow the hooks to be used */
1594 		hook1->hk_flags &= ~HK_INVALID;
1595 		hook2->hk_flags &= ~HK_INVALID;
1596 	}
1597 	NG_HOOK_UNREF(hook1);
1598 	NG_HOOK_UNREF(hook2);
1599 	return (error);
1600 }
1601 
1602 /************************************************************************
1603 		Utility routines to send self messages
1604 ************************************************************************/
1605 
1606 /* Shut this node down as soon as everyone is clear of it */
1607 /* Should add arg "immediately" to jump the queue */
1608 int
1609 ng_rmnode_self(node_p node)
1610 {
1611 	int		error;
1612 
1613 	if (node == &ng_deadnode)
1614 		return (0);
1615 	node->nd_flags |= NGF_INVALID;
1616 	if (node->nd_flags & NGF_CLOSING)
1617 		return (0);
1618 
1619 	error = ng_send_fn(node, NULL, &ng_rmnode, NULL, 0);
1620 	return (error);
1621 }
1622 
1623 static void
1624 ng_rmhook_part2(node_p node, hook_p hook, void *arg1, int arg2)
1625 {
1626 	ng_destroy_hook(hook);
1627 	return ;
1628 }
1629 
1630 int
1631 ng_rmhook_self(hook_p hook)
1632 {
1633 	int		error;
1634 	node_p node = NG_HOOK_NODE(hook);
1635 
1636 	if (node == &ng_deadnode)
1637 		return (0);
1638 
1639 	error = ng_send_fn(node, hook, &ng_rmhook_part2, NULL, 0);
1640 	return (error);
1641 }
1642 
1643 /***********************************************************************
1644  * Parse and verify a string of the form:  <NODE:><PATH>
1645  *
1646  * Such a string can refer to a specific node or a specific hook
1647  * on a specific node, depending on how you look at it. In the
1648  * latter case, the PATH component must not end in a dot.
1649  *
1650  * Both <NODE:> and <PATH> are optional. The <PATH> is a string
1651  * of hook names separated by dots. This breaks out the original
1652  * string, setting *nodep to "NODE" (or NULL if none) and *pathp
1653  * to "PATH" (or NULL if degenerate). Also, *hookp will point to
1654  * the final hook component of <PATH>, if any, otherwise NULL.
1655  *
1656  * This returns -1 if the path is malformed. The char ** are optional.
1657  ***********************************************************************/
1658 int
1659 ng_path_parse(char *addr, char **nodep, char **pathp, char **hookp)
1660 {
1661 	char	*node, *path, *hook;
1662 	int	k;
1663 
1664 	/*
1665 	 * Extract absolute NODE, if any
1666 	 */
1667 	for (path = addr; *path && *path != ':'; path++);
1668 	if (*path) {
1669 		node = addr;	/* Here's the NODE */
1670 		*path++ = '\0';	/* Here's the PATH */
1671 
1672 		/* Node name must not be empty */
1673 		if (!*node)
1674 			return -1;
1675 
1676 		/* A name of "." is OK; otherwise '.' not allowed */
1677 		if (strcmp(node, ".") != 0) {
1678 			for (k = 0; node[k]; k++)
1679 				if (node[k] == '.')
1680 					return -1;
1681 		}
1682 	} else {
1683 		node = NULL;	/* No absolute NODE */
1684 		path = addr;	/* Here's the PATH */
1685 	}
1686 
1687 	/* Snoop for illegal characters in PATH */
1688 	for (k = 0; path[k]; k++)
1689 		if (path[k] == ':')
1690 			return -1;
1691 
1692 	/* Check for no repeated dots in PATH */
1693 	for (k = 0; path[k]; k++)
1694 		if (path[k] == '.' && path[k + 1] == '.')
1695 			return -1;
1696 
1697 	/* Remove extra (degenerate) dots from beginning or end of PATH */
1698 	if (path[0] == '.')
1699 		path++;
1700 	if (*path && path[strlen(path) - 1] == '.')
1701 		path[strlen(path) - 1] = 0;
1702 
1703 	/* If PATH has a dot, then we're not talking about a hook */
1704 	if (*path) {
1705 		for (hook = path, k = 0; path[k]; k++)
1706 			if (path[k] == '.') {
1707 				hook = NULL;
1708 				break;
1709 			}
1710 	} else
1711 		path = hook = NULL;
1712 
1713 	/* Done */
1714 	if (nodep)
1715 		*nodep = node;
1716 	if (pathp)
1717 		*pathp = path;
1718 	if (hookp)
1719 		*hookp = hook;
1720 	return (0);
1721 }
1722 
1723 /*
1724  * Given a path, which may be absolute or relative, and a starting node,
1725  * return the destination node.
1726  */
1727 int
1728 ng_path2noderef(node_p here, const char *address, node_p *destp,
1729     hook_p *lasthook)
1730 {
1731 	char    fullpath[NG_PATHSIZ];
1732 	char   *nodename, *path;
1733 	node_p  node, oldnode;
1734 
1735 	/* Initialize */
1736 	if (destp == NULL) {
1737 		TRAP_ERROR();
1738 		return EINVAL;
1739 	}
1740 	*destp = NULL;
1741 
1742 	/* Make a writable copy of address for ng_path_parse() */
1743 	strncpy(fullpath, address, sizeof(fullpath) - 1);
1744 	fullpath[sizeof(fullpath) - 1] = '\0';
1745 
1746 	/* Parse out node and sequence of hooks */
1747 	if (ng_path_parse(fullpath, &nodename, &path, NULL) < 0) {
1748 		TRAP_ERROR();
1749 		return EINVAL;
1750 	}
1751 
1752 	/*
1753 	 * For an absolute address, jump to the starting node.
1754 	 * Note that this holds a reference on the node for us.
1755 	 * Don't forget to drop the reference if we don't need it.
1756 	 */
1757 	if (nodename) {
1758 		node = ng_name2noderef(here, nodename);
1759 		if (node == NULL) {
1760 			TRAP_ERROR();
1761 			return (ENOENT);
1762 		}
1763 	} else {
1764 		if (here == NULL) {
1765 			TRAP_ERROR();
1766 			return (EINVAL);
1767 		}
1768 		node = here;
1769 		NG_NODE_REF(node);
1770 	}
1771 
1772 	if (path == NULL) {
1773 		if (lasthook != NULL)
1774 			*lasthook = NULL;
1775 		*destp = node;
1776 		return (0);
1777 	}
1778 
1779 	/*
1780 	 * Now follow the sequence of hooks
1781 	 *
1782 	 * XXXGL: The path may demolish as we go the sequence, but if
1783 	 * we hold the topology mutex at critical places, then, I hope,
1784 	 * we would always have valid pointers in hand, although the
1785 	 * path behind us may no longer exist.
1786 	 */
1787 	for (;;) {
1788 		hook_p hook;
1789 		char *segment;
1790 
1791 		/*
1792 		 * Break out the next path segment. Replace the dot we just
1793 		 * found with a NUL; "path" points to the next segment (or the
1794 		 * NUL at the end).
1795 		 */
1796 		for (segment = path; *path != '\0'; path++) {
1797 			if (*path == '.') {
1798 				*path++ = '\0';
1799 				break;
1800 			}
1801 		}
1802 
1803 		/* We have a segment, so look for a hook by that name */
1804 		hook = ng_findhook(node, segment);
1805 
1806 		TOPOLOGY_WLOCK();
1807 		/* Can't get there from here... */
1808 		if (hook == NULL || NG_HOOK_PEER(hook) == NULL ||
1809 		    NG_HOOK_NOT_VALID(hook) ||
1810 		    NG_HOOK_NOT_VALID(NG_HOOK_PEER(hook))) {
1811 			TRAP_ERROR();
1812 			NG_NODE_UNREF(node);
1813 			TOPOLOGY_WUNLOCK();
1814 			return (ENOENT);
1815 		}
1816 
1817 		/*
1818 		 * Hop on over to the next node
1819 		 * XXX
1820 		 * Big race conditions here as hooks and nodes go away
1821 		 * *** Idea.. store an ng_ID_t in each hook and use that
1822 		 * instead of the direct hook in this crawl?
1823 		 */
1824 		oldnode = node;
1825 		if ((node = NG_PEER_NODE(hook)))
1826 			NG_NODE_REF(node);	/* XXX RACE */
1827 		NG_NODE_UNREF(oldnode);	/* XXX another race */
1828 		if (NG_NODE_NOT_VALID(node)) {
1829 			NG_NODE_UNREF(node);	/* XXX more races */
1830 			TOPOLOGY_WUNLOCK();
1831 			TRAP_ERROR();
1832 			return (ENXIO);
1833 		}
1834 
1835 		if (*path == '\0') {
1836 			if (lasthook != NULL) {
1837 				if (hook != NULL) {
1838 					*lasthook = NG_HOOK_PEER(hook);
1839 					NG_HOOK_REF(*lasthook);
1840 				} else
1841 					*lasthook = NULL;
1842 			}
1843 			TOPOLOGY_WUNLOCK();
1844 			*destp = node;
1845 			return (0);
1846 		}
1847 		TOPOLOGY_WUNLOCK();
1848 	}
1849 }
1850 
1851 /***************************************************************\
1852 * Input queue handling.
1853 * All activities are submitted to the node via the input queue
1854 * which implements a multiple-reader/single-writer gate.
1855 * Items which cannot be handled immediately are queued.
1856 *
1857 * read-write queue locking inline functions			*
1858 \***************************************************************/
1859 
1860 static __inline void	ng_queue_rw(node_p node, item_p  item, int rw);
1861 static __inline item_p	ng_dequeue(node_p node, int *rw);
1862 static __inline item_p	ng_acquire_read(node_p node, item_p  item);
1863 static __inline item_p	ng_acquire_write(node_p node, item_p  item);
1864 static __inline void	ng_leave_read(node_p node);
1865 static __inline void	ng_leave_write(node_p node);
1866 
1867 /*
1868  * Definition of the bits fields in the ng_queue flag word.
1869  * Defined here rather than in netgraph.h because no-one should fiddle
1870  * with them.
1871  *
1872  * The ordering here may be important! don't shuffle these.
1873  */
1874 /*-
1875  Safety Barrier--------+ (adjustable to suit taste) (not used yet)
1876                        |
1877                        V
1878 +-------+-------+-------+-------+-------+-------+-------+-------+
1879   | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
1880   | |A|c|t|i|v|e| |R|e|a|d|e|r| |C|o|u|n|t| | | | | | | | | |P|A|
1881   | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |O|W|
1882 +-------+-------+-------+-------+-------+-------+-------+-------+
1883   \___________________________ ____________________________/ | |
1884                             V                                | |
1885                   [active reader count]                      | |
1886                                                              | |
1887             Operation Pending -------------------------------+ |
1888                                                                |
1889           Active Writer ---------------------------------------+
1890 
1891 Node queue has such semantics:
1892 - All flags modifications are atomic.
1893 - Reader count can be incremented only if there is no writer or pending flags.
1894   As soon as this can't be done with single operation, it is implemented with
1895   spin loop and atomic_cmpset().
1896 - Writer flag can be set only if there is no any bits set.
1897   It is implemented with atomic_cmpset().
1898 - Pending flag can be set any time, but to avoid collision on queue processing
1899   all queue fields are protected by the mutex.
1900 - Queue processing thread reads queue holding the mutex, but releases it while
1901   processing. When queue is empty pending flag is removed.
1902 */
1903 
1904 #define WRITER_ACTIVE	0x00000001
1905 #define OP_PENDING	0x00000002
1906 #define READER_INCREMENT 0x00000004
1907 #define READER_MASK	0xfffffffc	/* Not valid if WRITER_ACTIVE is set */
1908 #define SAFETY_BARRIER	0x00100000	/* 128K items queued should be enough */
1909 
1910 /* Defines of more elaborate states on the queue */
1911 /* Mask of bits a new read cares about */
1912 #define NGQ_RMASK	(WRITER_ACTIVE|OP_PENDING)
1913 
1914 /* Mask of bits a new write cares about */
1915 #define NGQ_WMASK	(NGQ_RMASK|READER_MASK)
1916 
1917 /* Test to decide if there is something on the queue. */
1918 #define QUEUE_ACTIVE(QP) ((QP)->q_flags & OP_PENDING)
1919 
1920 /* How to decide what the next queued item is. */
1921 #define HEAD_IS_READER(QP)  NGI_QUEUED_READER(STAILQ_FIRST(&(QP)->queue))
1922 #define HEAD_IS_WRITER(QP)  NGI_QUEUED_WRITER(STAILQ_FIRST(&(QP)->queue)) /* notused */
1923 
1924 /* Read the status to decide if the next item on the queue can now run. */
1925 #define QUEUED_READER_CAN_PROCEED(QP)			\
1926 		(((QP)->q_flags & (NGQ_RMASK & ~OP_PENDING)) == 0)
1927 #define QUEUED_WRITER_CAN_PROCEED(QP)			\
1928 		(((QP)->q_flags & (NGQ_WMASK & ~OP_PENDING)) == 0)
1929 
1930 /* Is there a chance of getting ANY work off the queue? */
1931 #define NEXT_QUEUED_ITEM_CAN_PROCEED(QP)				\
1932 	((HEAD_IS_READER(QP)) ? QUEUED_READER_CAN_PROCEED(QP) :		\
1933 				QUEUED_WRITER_CAN_PROCEED(QP))
1934 
1935 #define NGQRW_R 0
1936 #define NGQRW_W 1
1937 
1938 #define NGQ2_WORKQ	0x00000001
1939 
1940 /*
1941  * Taking into account the current state of the queue and node, possibly take
1942  * the next entry off the queue and return it. Return NULL if there was
1943  * nothing we could return, either because there really was nothing there, or
1944  * because the node was in a state where it cannot yet process the next item
1945  * on the queue.
1946  */
1947 static __inline item_p
1948 ng_dequeue(node_p node, int *rw)
1949 {
1950 	item_p item;
1951 	struct ng_queue *ngq = &node->nd_input_queue;
1952 
1953 	/* This MUST be called with the mutex held. */
1954 	mtx_assert(&ngq->q_mtx, MA_OWNED);
1955 
1956 	/* If there is nothing queued, then just return. */
1957 	if (!QUEUE_ACTIVE(ngq)) {
1958 		CTR4(KTR_NET, "%20s: node [%x] (%p) queue empty; "
1959 		    "queue flags 0x%lx", __func__,
1960 		    node->nd_ID, node, ngq->q_flags);
1961 		return (NULL);
1962 	}
1963 
1964 	/*
1965 	 * From here, we can assume there is a head item.
1966 	 * We need to find out what it is and if it can be dequeued, given
1967 	 * the current state of the node.
1968 	 */
1969 	if (HEAD_IS_READER(ngq)) {
1970 		while (1) {
1971 			long t = ngq->q_flags;
1972 			if (t & WRITER_ACTIVE) {
1973 				/* There is writer, reader can't proceed. */
1974 				CTR4(KTR_NET, "%20s: node [%x] (%p) queued "
1975 				    "reader can't proceed; queue flags 0x%lx",
1976 				    __func__, node->nd_ID, node, t);
1977 				return (NULL);
1978 			}
1979 			if (atomic_cmpset_acq_int(&ngq->q_flags, t,
1980 			    t + READER_INCREMENT))
1981 				break;
1982 			cpu_spinwait();
1983 		}
1984 		/* We have got reader lock for the node. */
1985 		*rw = NGQRW_R;
1986 	} else if (atomic_cmpset_acq_int(&ngq->q_flags, OP_PENDING,
1987 	    OP_PENDING + WRITER_ACTIVE)) {
1988 		/* We have got writer lock for the node. */
1989 		*rw = NGQRW_W;
1990 	} else {
1991 		/* There is somebody other, writer can't proceed. */
1992 		CTR4(KTR_NET, "%20s: node [%x] (%p) queued writer can't "
1993 		    "proceed; queue flags 0x%lx", __func__, node->nd_ID, node,
1994 		    ngq->q_flags);
1995 		return (NULL);
1996 	}
1997 
1998 	/*
1999 	 * Now we dequeue the request (whatever it may be) and correct the
2000 	 * pending flags and the next and last pointers.
2001 	 */
2002 	item = STAILQ_FIRST(&ngq->queue);
2003 	STAILQ_REMOVE_HEAD(&ngq->queue, el_next);
2004 	if (STAILQ_EMPTY(&ngq->queue))
2005 		atomic_clear_int(&ngq->q_flags, OP_PENDING);
2006 	CTR6(KTR_NET, "%20s: node [%x] (%p) returning item %p as %s; queue "
2007 	    "flags 0x%lx", __func__, node->nd_ID, node, item, *rw ? "WRITER" :
2008 	    "READER", ngq->q_flags);
2009 	return (item);
2010 }
2011 
2012 /*
2013  * Queue a packet to be picked up later by someone else.
2014  * If the queue could be run now, add node to the queue handler's worklist.
2015  */
2016 static __inline void
2017 ng_queue_rw(node_p node, item_p  item, int rw)
2018 {
2019 	struct ng_queue *ngq = &node->nd_input_queue;
2020 	if (rw == NGQRW_W)
2021 		NGI_SET_WRITER(item);
2022 	else
2023 		NGI_SET_READER(item);
2024 	item->depth = 1;
2025 
2026 	NG_QUEUE_LOCK(ngq);
2027 	/* Set OP_PENDING flag and enqueue the item. */
2028 	atomic_set_int(&ngq->q_flags, OP_PENDING);
2029 	STAILQ_INSERT_TAIL(&ngq->queue, item, el_next);
2030 
2031 	CTR5(KTR_NET, "%20s: node [%x] (%p) queued item %p as %s", __func__,
2032 	    node->nd_ID, node, item, rw ? "WRITER" : "READER" );
2033 
2034 	/*
2035 	 * We can take the worklist lock with the node locked
2036 	 * BUT NOT THE REVERSE!
2037 	 */
2038 	if (NEXT_QUEUED_ITEM_CAN_PROCEED(ngq))
2039 		ng_worklist_add(node);
2040 	NG_QUEUE_UNLOCK(ngq);
2041 }
2042 
2043 /* Acquire reader lock on node. If node is busy, queue the packet. */
2044 static __inline item_p
2045 ng_acquire_read(node_p node, item_p item)
2046 {
2047 	KASSERT(node != &ng_deadnode,
2048 	    ("%s: working on deadnode", __func__));
2049 
2050 	/* Reader needs node without writer and pending items. */
2051 	for (;;) {
2052 		long t = node->nd_input_queue.q_flags;
2053 		if (t & NGQ_RMASK)
2054 			break; /* Node is not ready for reader. */
2055 		if (atomic_cmpset_acq_int(&node->nd_input_queue.q_flags, t,
2056 		    t + READER_INCREMENT)) {
2057 	    		/* Successfully grabbed node */
2058 			CTR4(KTR_NET, "%20s: node [%x] (%p) acquired item %p",
2059 			    __func__, node->nd_ID, node, item);
2060 			return (item);
2061 		}
2062 		cpu_spinwait();
2063 	}
2064 
2065 	/* Queue the request for later. */
2066 	ng_queue_rw(node, item, NGQRW_R);
2067 
2068 	return (NULL);
2069 }
2070 
2071 /* Acquire writer lock on node. If node is busy, queue the packet. */
2072 static __inline item_p
2073 ng_acquire_write(node_p node, item_p item)
2074 {
2075 	KASSERT(node != &ng_deadnode,
2076 	    ("%s: working on deadnode", __func__));
2077 
2078 	/* Writer needs completely idle node. */
2079 	if (atomic_cmpset_acq_int(&node->nd_input_queue.q_flags, 0,
2080 	    WRITER_ACTIVE)) {
2081 	    	/* Successfully grabbed node */
2082 		CTR4(KTR_NET, "%20s: node [%x] (%p) acquired item %p",
2083 		    __func__, node->nd_ID, node, item);
2084 		return (item);
2085 	}
2086 
2087 	/* Queue the request for later. */
2088 	ng_queue_rw(node, item, NGQRW_W);
2089 
2090 	return (NULL);
2091 }
2092 
2093 #if 0
2094 static __inline item_p
2095 ng_upgrade_write(node_p node, item_p item)
2096 {
2097 	struct ng_queue *ngq = &node->nd_input_queue;
2098 	KASSERT(node != &ng_deadnode,
2099 	    ("%s: working on deadnode", __func__));
2100 
2101 	NGI_SET_WRITER(item);
2102 
2103 	NG_QUEUE_LOCK(ngq);
2104 
2105 	/*
2106 	 * There will never be no readers as we are there ourselves.
2107 	 * Set the WRITER_ACTIVE flags ASAP to block out fast track readers.
2108 	 * The caller we are running from will call ng_leave_read()
2109 	 * soon, so we must account for that. We must leave again with the
2110 	 * READER lock. If we find other readers, then
2111 	 * queue the request for later. However "later" may be rignt now
2112 	 * if there are no readers. We don't really care if there are queued
2113 	 * items as we will bypass them anyhow.
2114 	 */
2115 	atomic_add_int(&ngq->q_flags, WRITER_ACTIVE - READER_INCREMENT);
2116 	if ((ngq->q_flags & (NGQ_WMASK & ~OP_PENDING)) == WRITER_ACTIVE) {
2117 		NG_QUEUE_UNLOCK(ngq);
2118 
2119 		/* It's just us, act on the item. */
2120 		/* will NOT drop writer lock when done */
2121 		ng_apply_item(node, item, 0);
2122 
2123 		/*
2124 		 * Having acted on the item, atomically
2125 		 * downgrade back to READER and finish up.
2126 	 	 */
2127 		atomic_add_int(&ngq->q_flags, READER_INCREMENT - WRITER_ACTIVE);
2128 
2129 		/* Our caller will call ng_leave_read() */
2130 		return;
2131 	}
2132 	/*
2133 	 * It's not just us active, so queue us AT THE HEAD.
2134 	 * "Why?" I hear you ask.
2135 	 * Put us at the head of the queue as we've already been
2136 	 * through it once. If there is nothing else waiting,
2137 	 * set the correct flags.
2138 	 */
2139 	if (STAILQ_EMPTY(&ngq->queue)) {
2140 		/* We've gone from, 0 to 1 item in the queue */
2141 		atomic_set_int(&ngq->q_flags, OP_PENDING);
2142 
2143 		CTR3(KTR_NET, "%20s: node [%x] (%p) set OP_PENDING", __func__,
2144 		    node->nd_ID, node);
2145 	};
2146 	STAILQ_INSERT_HEAD(&ngq->queue, item, el_next);
2147 	CTR4(KTR_NET, "%20s: node [%x] (%p) requeued item %p as WRITER",
2148 	    __func__, node->nd_ID, node, item );
2149 
2150 	/* Reverse what we did above. That downgrades us back to reader */
2151 	atomic_add_int(&ngq->q_flags, READER_INCREMENT - WRITER_ACTIVE);
2152 	if (QUEUE_ACTIVE(ngq) && NEXT_QUEUED_ITEM_CAN_PROCEED(ngq))
2153 		ng_worklist_add(node);
2154 	NG_QUEUE_UNLOCK(ngq);
2155 
2156 	return;
2157 }
2158 #endif
2159 
2160 /* Release reader lock. */
2161 static __inline void
2162 ng_leave_read(node_p node)
2163 {
2164 	atomic_subtract_rel_int(&node->nd_input_queue.q_flags, READER_INCREMENT);
2165 }
2166 
2167 /* Release writer lock. */
2168 static __inline void
2169 ng_leave_write(node_p node)
2170 {
2171 	atomic_clear_rel_int(&node->nd_input_queue.q_flags, WRITER_ACTIVE);
2172 }
2173 
2174 /* Purge node queue. Called on node shutdown. */
2175 static void
2176 ng_flush_input_queue(node_p node)
2177 {
2178 	struct ng_queue *ngq = &node->nd_input_queue;
2179 	item_p item;
2180 
2181 	NG_QUEUE_LOCK(ngq);
2182 	while ((item = STAILQ_FIRST(&ngq->queue)) != NULL) {
2183 		STAILQ_REMOVE_HEAD(&ngq->queue, el_next);
2184 		if (STAILQ_EMPTY(&ngq->queue))
2185 			atomic_clear_int(&ngq->q_flags, OP_PENDING);
2186 		NG_QUEUE_UNLOCK(ngq);
2187 
2188 		/* If the item is supplying a callback, call it with an error */
2189 		if (item->apply != NULL) {
2190 			if (item->depth == 1)
2191 				item->apply->error = ENOENT;
2192 			if (refcount_release(&item->apply->refs)) {
2193 				(*item->apply->apply)(item->apply->context,
2194 				    item->apply->error);
2195 			}
2196 		}
2197 		NG_FREE_ITEM(item);
2198 		NG_QUEUE_LOCK(ngq);
2199 	}
2200 	NG_QUEUE_UNLOCK(ngq);
2201 }
2202 
2203 /***********************************************************************
2204 * Externally visible method for sending or queueing messages or data.
2205 ***********************************************************************/
2206 
2207 /*
2208  * The module code should have filled out the item correctly by this stage:
2209  * Common:
2210  *    reference to destination node.
2211  *    Reference to destination rcv hook if relevant.
2212  *    apply pointer must be or NULL or reference valid struct ng_apply_info.
2213  * Data:
2214  *    pointer to mbuf
2215  * Control_Message:
2216  *    pointer to msg.
2217  *    ID of original sender node. (return address)
2218  * Function:
2219  *    Function pointer
2220  *    void * argument
2221  *    integer argument
2222  *
2223  * The nodes have several routines and macros to help with this task:
2224  */
2225 
2226 int
2227 ng_snd_item(item_p item, int flags)
2228 {
2229 	hook_p hook;
2230 	node_p node;
2231 	int queue, rw;
2232 	struct ng_queue *ngq;
2233 	int error = 0;
2234 
2235 	/* We are sending item, so it must be present! */
2236 	KASSERT(item != NULL, ("ng_snd_item: item is NULL"));
2237 
2238 #ifdef	NETGRAPH_DEBUG
2239 	_ngi_check(item, __FILE__, __LINE__);
2240 #endif
2241 
2242 	/* Item was sent once more, postpone apply() call. */
2243 	if (item->apply)
2244 		refcount_acquire(&item->apply->refs);
2245 
2246 	node = NGI_NODE(item);
2247 	/* Node is never optional. */
2248 	KASSERT(node != NULL, ("ng_snd_item: node is NULL"));
2249 
2250 	hook = NGI_HOOK(item);
2251 	/* Valid hook and mbuf are mandatory for data. */
2252 	if ((item->el_flags & NGQF_TYPE) == NGQF_DATA) {
2253 		KASSERT(hook != NULL, ("ng_snd_item: hook for data is NULL"));
2254 		if (NGI_M(item) == NULL)
2255 			ERROUT(EINVAL);
2256 		CHECK_DATA_MBUF(NGI_M(item));
2257 	}
2258 
2259 	/*
2260 	 * If the item or the node specifies single threading, force
2261 	 * writer semantics. Similarly, the node may say one hook always
2262 	 * produces writers. These are overrides.
2263 	 */
2264 	if (((item->el_flags & NGQF_RW) == NGQF_WRITER) ||
2265 	    (node->nd_flags & NGF_FORCE_WRITER) ||
2266 	    (hook && (hook->hk_flags & HK_FORCE_WRITER))) {
2267 		rw = NGQRW_W;
2268 	} else {
2269 		rw = NGQRW_R;
2270 	}
2271 
2272 	/*
2273 	 * If sender or receiver requests queued delivery, or call graph
2274 	 * loops back from outbound to inbound path, or stack usage
2275 	 * level is dangerous - enqueue message.
2276 	 */
2277 	if ((flags & NG_QUEUE) || (hook && (hook->hk_flags & HK_QUEUE))) {
2278 		queue = 1;
2279 	} else if (hook && (hook->hk_flags & HK_TO_INBOUND) &&
2280 	    curthread->td_ng_outbound) {
2281 		queue = 1;
2282 	} else {
2283 		queue = 0;
2284 
2285 		/*
2286 		 * Most of netgraph nodes have small stack consumption and
2287 		 * for them 25% of free stack space is more than enough.
2288 		 * Nodes/hooks with higher stack usage should be marked as
2289 		 * HI_STACK. For them 50% of stack will be guaranteed then.
2290 		 * XXX: Values 25% and 50% are completely empirical.
2291 		 */
2292 		size_t	st, su, sl;
2293 		GET_STACK_USAGE(st, su);
2294 		sl = st - su;
2295 		if ((sl * 4 < st) || ((sl * 2 < st) &&
2296 		    ((node->nd_flags & NGF_HI_STACK) || (hook &&
2297 		    (hook->hk_flags & HK_HI_STACK)))))
2298 			queue = 1;
2299 	}
2300 
2301 	if (queue) {
2302 		/* Put it on the queue for that node*/
2303 		ng_queue_rw(node, item, rw);
2304 		return ((flags & NG_PROGRESS) ? EINPROGRESS : 0);
2305 	}
2306 
2307 	/*
2308 	 * We already decided how we will be queueud or treated.
2309 	 * Try get the appropriate operating permission.
2310 	 */
2311  	if (rw == NGQRW_R)
2312 		item = ng_acquire_read(node, item);
2313 	else
2314 		item = ng_acquire_write(node, item);
2315 
2316 	/* Item was queued while trying to get permission. */
2317 	if (item == NULL)
2318 		return ((flags & NG_PROGRESS) ? EINPROGRESS : 0);
2319 
2320 	NGI_GET_NODE(item, node); /* zaps stored node */
2321 
2322 	item->depth++;
2323 	error = ng_apply_item(node, item, rw); /* drops r/w lock when done */
2324 
2325 	/* If something is waiting on queue and ready, schedule it. */
2326 	ngq = &node->nd_input_queue;
2327 	if (QUEUE_ACTIVE(ngq)) {
2328 		NG_QUEUE_LOCK(ngq);
2329 		if (QUEUE_ACTIVE(ngq) && NEXT_QUEUED_ITEM_CAN_PROCEED(ngq))
2330 			ng_worklist_add(node);
2331 		NG_QUEUE_UNLOCK(ngq);
2332 	}
2333 
2334 	/*
2335 	 * Node may go away as soon as we remove the reference.
2336 	 * Whatever we do, DO NOT access the node again!
2337 	 */
2338 	NG_NODE_UNREF(node);
2339 
2340 	return (error);
2341 
2342 done:
2343 	/* If was not sent, apply callback here. */
2344 	if (item->apply != NULL) {
2345 		if (item->depth == 0 && error != 0)
2346 			item->apply->error = error;
2347 		if (refcount_release(&item->apply->refs)) {
2348 			(*item->apply->apply)(item->apply->context,
2349 			    item->apply->error);
2350 		}
2351 	}
2352 
2353 	NG_FREE_ITEM(item);
2354 	return (error);
2355 }
2356 
2357 /*
2358  * We have an item that was possibly queued somewhere.
2359  * It should contain all the information needed
2360  * to run it on the appropriate node/hook.
2361  * If there is apply pointer and we own the last reference, call apply().
2362  */
2363 static int
2364 ng_apply_item(node_p node, item_p item, int rw)
2365 {
2366 	hook_p  hook;
2367 	ng_rcvdata_t *rcvdata;
2368 	ng_rcvmsg_t *rcvmsg;
2369 	struct ng_apply_info *apply;
2370 	int	error = 0, depth;
2371 
2372 	/* Node and item are never optional. */
2373 	KASSERT(node != NULL, ("ng_apply_item: node is NULL"));
2374 	KASSERT(item != NULL, ("ng_apply_item: item is NULL"));
2375 
2376 	NGI_GET_HOOK(item, hook); /* clears stored hook */
2377 #ifdef	NETGRAPH_DEBUG
2378 	_ngi_check(item, __FILE__, __LINE__);
2379 #endif
2380 
2381 	apply = item->apply;
2382 	depth = item->depth;
2383 
2384 	switch (item->el_flags & NGQF_TYPE) {
2385 	case NGQF_DATA:
2386 		/*
2387 		 * Check things are still ok as when we were queued.
2388 		 */
2389 		KASSERT(hook != NULL, ("ng_apply_item: hook for data is NULL"));
2390 		if (NG_HOOK_NOT_VALID(hook) ||
2391 		    NG_NODE_NOT_VALID(node)) {
2392 			error = EIO;
2393 			NG_FREE_ITEM(item);
2394 			break;
2395 		}
2396 		/*
2397 		 * If no receive method, just silently drop it.
2398 		 * Give preference to the hook over-ride method.
2399 		 */
2400 		if ((!(rcvdata = hook->hk_rcvdata)) &&
2401 		    (!(rcvdata = NG_HOOK_NODE(hook)->nd_type->rcvdata))) {
2402 			error = 0;
2403 			NG_FREE_ITEM(item);
2404 			break;
2405 		}
2406 		error = (*rcvdata)(hook, item);
2407 		break;
2408 	case NGQF_MESG:
2409 		if (hook && NG_HOOK_NOT_VALID(hook)) {
2410 			/*
2411 			 * The hook has been zapped then we can't use it.
2412 			 * Immediately drop its reference.
2413 			 * The message may not need it.
2414 			 */
2415 			NG_HOOK_UNREF(hook);
2416 			hook = NULL;
2417 		}
2418 		/*
2419 		 * Similarly, if the node is a zombie there is
2420 		 * nothing we can do with it, drop everything.
2421 		 */
2422 		if (NG_NODE_NOT_VALID(node)) {
2423 			TRAP_ERROR();
2424 			error = EINVAL;
2425 			NG_FREE_ITEM(item);
2426 			break;
2427 		}
2428 		/*
2429 		 * Call the appropriate message handler for the object.
2430 		 * It is up to the message handler to free the message.
2431 		 * If it's a generic message, handle it generically,
2432 		 * otherwise call the type's message handler (if it exists).
2433 		 * XXX (race). Remember that a queued message may
2434 		 * reference a node or hook that has just been
2435 		 * invalidated. It will exist as the queue code
2436 		 * is holding a reference, but..
2437 		 */
2438 		if ((NGI_MSG(item)->header.typecookie == NGM_GENERIC_COOKIE) &&
2439 		    ((NGI_MSG(item)->header.flags & NGF_RESP) == 0)) {
2440 			error = ng_generic_msg(node, item, hook);
2441 			break;
2442 		}
2443 		if (((!hook) || (!(rcvmsg = hook->hk_rcvmsg))) &&
2444 		    (!(rcvmsg = node->nd_type->rcvmsg))) {
2445 			TRAP_ERROR();
2446 			error = 0;
2447 			NG_FREE_ITEM(item);
2448 			break;
2449 		}
2450 		error = (*rcvmsg)(node, item, hook);
2451 		break;
2452 	case NGQF_FN:
2453 	case NGQF_FN2:
2454 		/*
2455 		 * In the case of the shutdown message we allow it to hit
2456 		 * even if the node is invalid.
2457 		 */
2458 		if (NG_NODE_NOT_VALID(node) &&
2459 		    NGI_FN(item) != &ng_rmnode) {
2460 			TRAP_ERROR();
2461 			error = EINVAL;
2462 			NG_FREE_ITEM(item);
2463 			break;
2464 		}
2465 		/* Same is about some internal functions and invalid hook. */
2466 		if (hook && NG_HOOK_NOT_VALID(hook) &&
2467 		    NGI_FN2(item) != &ng_con_part2 &&
2468 		    NGI_FN2(item) != &ng_con_part3 &&
2469 		    NGI_FN(item) != &ng_rmhook_part2) {
2470 			TRAP_ERROR();
2471 			error = EINVAL;
2472 			NG_FREE_ITEM(item);
2473 			break;
2474 		}
2475 
2476 		if ((item->el_flags & NGQF_TYPE) == NGQF_FN) {
2477 			(*NGI_FN(item))(node, hook, NGI_ARG1(item),
2478 			    NGI_ARG2(item));
2479 			NG_FREE_ITEM(item);
2480 		} else	/* it is NGQF_FN2 */
2481 			error = (*NGI_FN2(item))(node, item, hook);
2482 		break;
2483 	}
2484 	/*
2485 	 * We held references on some of the resources
2486 	 * that we took from the item. Now that we have
2487 	 * finished doing everything, drop those references.
2488 	 */
2489 	if (hook)
2490 		NG_HOOK_UNREF(hook);
2491 
2492  	if (rw == NGQRW_R)
2493 		ng_leave_read(node);
2494 	else
2495 		ng_leave_write(node);
2496 
2497 	/* Apply callback. */
2498 	if (apply != NULL) {
2499 		if (depth == 1 && error != 0)
2500 			apply->error = error;
2501 		if (refcount_release(&apply->refs))
2502 			(*apply->apply)(apply->context, apply->error);
2503 	}
2504 
2505 	return (error);
2506 }
2507 
2508 /***********************************************************************
2509  * Implement the 'generic' control messages
2510  ***********************************************************************/
2511 static int
2512 ng_generic_msg(node_p here, item_p item, hook_p lasthook)
2513 {
2514 	int error = 0;
2515 	struct ng_mesg *msg;
2516 	struct ng_mesg *resp = NULL;
2517 
2518 	NGI_GET_MSG(item, msg);
2519 	if (msg->header.typecookie != NGM_GENERIC_COOKIE) {
2520 		TRAP_ERROR();
2521 		error = EINVAL;
2522 		goto out;
2523 	}
2524 	switch (msg->header.cmd) {
2525 	case NGM_SHUTDOWN:
2526 		ng_rmnode(here, NULL, NULL, 0);
2527 		break;
2528 	case NGM_MKPEER:
2529 	    {
2530 		struct ngm_mkpeer *const mkp = (struct ngm_mkpeer *) msg->data;
2531 
2532 		if (msg->header.arglen != sizeof(*mkp)) {
2533 			TRAP_ERROR();
2534 			error = EINVAL;
2535 			break;
2536 		}
2537 		mkp->type[sizeof(mkp->type) - 1] = '\0';
2538 		mkp->ourhook[sizeof(mkp->ourhook) - 1] = '\0';
2539 		mkp->peerhook[sizeof(mkp->peerhook) - 1] = '\0';
2540 		error = ng_mkpeer(here, mkp->ourhook, mkp->peerhook, mkp->type);
2541 		break;
2542 	    }
2543 	case NGM_CONNECT:
2544 	    {
2545 		struct ngm_connect *const con =
2546 			(struct ngm_connect *) msg->data;
2547 		node_p node2;
2548 
2549 		if (msg->header.arglen != sizeof(*con)) {
2550 			TRAP_ERROR();
2551 			error = EINVAL;
2552 			break;
2553 		}
2554 		con->path[sizeof(con->path) - 1] = '\0';
2555 		con->ourhook[sizeof(con->ourhook) - 1] = '\0';
2556 		con->peerhook[sizeof(con->peerhook) - 1] = '\0';
2557 		/* Don't forget we get a reference.. */
2558 		error = ng_path2noderef(here, con->path, &node2, NULL);
2559 		if (error)
2560 			break;
2561 		error = ng_con_nodes(item, here, con->ourhook,
2562 		    node2, con->peerhook);
2563 		NG_NODE_UNREF(node2);
2564 		break;
2565 	    }
2566 	case NGM_NAME:
2567 	    {
2568 		struct ngm_name *const nam = (struct ngm_name *) msg->data;
2569 
2570 		if (msg->header.arglen != sizeof(*nam)) {
2571 			TRAP_ERROR();
2572 			error = EINVAL;
2573 			break;
2574 		}
2575 		nam->name[sizeof(nam->name) - 1] = '\0';
2576 		error = ng_name_node(here, nam->name);
2577 		break;
2578 	    }
2579 	case NGM_RMHOOK:
2580 	    {
2581 		struct ngm_rmhook *const rmh = (struct ngm_rmhook *) msg->data;
2582 		hook_p hook;
2583 
2584 		if (msg->header.arglen != sizeof(*rmh)) {
2585 			TRAP_ERROR();
2586 			error = EINVAL;
2587 			break;
2588 		}
2589 		rmh->ourhook[sizeof(rmh->ourhook) - 1] = '\0';
2590 		if ((hook = ng_findhook(here, rmh->ourhook)) != NULL)
2591 			ng_destroy_hook(hook);
2592 		break;
2593 	    }
2594 	case NGM_NODEINFO:
2595 	    {
2596 		struct nodeinfo *ni;
2597 
2598 		NG_MKRESPONSE(resp, msg, sizeof(*ni), M_NOWAIT);
2599 		if (resp == NULL) {
2600 			error = ENOMEM;
2601 			break;
2602 		}
2603 
2604 		/* Fill in node info */
2605 		ni = (struct nodeinfo *) resp->data;
2606 		if (NG_NODE_HAS_NAME(here))
2607 			strcpy(ni->name, NG_NODE_NAME(here));
2608 		strcpy(ni->type, here->nd_type->name);
2609 		ni->id = ng_node2ID(here);
2610 		ni->hooks = here->nd_numhooks;
2611 		break;
2612 	    }
2613 	case NGM_LISTHOOKS:
2614 	    {
2615 		const int nhooks = here->nd_numhooks;
2616 		struct hooklist *hl;
2617 		struct nodeinfo *ni;
2618 		hook_p hook;
2619 
2620 		/* Get response struct */
2621 		NG_MKRESPONSE(resp, msg, sizeof(*hl) +
2622 		    (nhooks * sizeof(struct linkinfo)), M_NOWAIT);
2623 		if (resp == NULL) {
2624 			error = ENOMEM;
2625 			break;
2626 		}
2627 		hl = (struct hooklist *) resp->data;
2628 		ni = &hl->nodeinfo;
2629 
2630 		/* Fill in node info */
2631 		if (NG_NODE_HAS_NAME(here))
2632 			strcpy(ni->name, NG_NODE_NAME(here));
2633 		strcpy(ni->type, here->nd_type->name);
2634 		ni->id = ng_node2ID(here);
2635 
2636 		/* Cycle through the linked list of hooks */
2637 		ni->hooks = 0;
2638 		LIST_FOREACH(hook, &here->nd_hooks, hk_hooks) {
2639 			struct linkinfo *const link = &hl->link[ni->hooks];
2640 
2641 			if (ni->hooks >= nhooks) {
2642 				log(LOG_ERR, "%s: number of %s changed\n",
2643 				    __func__, "hooks");
2644 				break;
2645 			}
2646 			if (NG_HOOK_NOT_VALID(hook))
2647 				continue;
2648 			strcpy(link->ourhook, NG_HOOK_NAME(hook));
2649 			strcpy(link->peerhook, NG_PEER_HOOK_NAME(hook));
2650 			if (NG_PEER_NODE_NAME(hook)[0] != '\0')
2651 				strcpy(link->nodeinfo.name,
2652 				    NG_PEER_NODE_NAME(hook));
2653 			strcpy(link->nodeinfo.type,
2654 			   NG_PEER_NODE(hook)->nd_type->name);
2655 			link->nodeinfo.id = ng_node2ID(NG_PEER_NODE(hook));
2656 			link->nodeinfo.hooks = NG_PEER_NODE(hook)->nd_numhooks;
2657 			ni->hooks++;
2658 		}
2659 		break;
2660 	    }
2661 
2662 	case NGM_LISTNODES:
2663 	    {
2664 		struct namelist *nl;
2665 		node_p node;
2666 		int i;
2667 
2668 		IDHASH_RLOCK();
2669 		/* Get response struct. */
2670 		NG_MKRESPONSE(resp, msg, sizeof(*nl) +
2671 		    (V_ng_nodes * sizeof(struct nodeinfo)), M_NOWAIT);
2672 		if (resp == NULL) {
2673 			IDHASH_RUNLOCK();
2674 			error = ENOMEM;
2675 			break;
2676 		}
2677 		nl = (struct namelist *) resp->data;
2678 
2679 		/* Cycle through the lists of nodes. */
2680 		nl->numnames = 0;
2681 		for (i = 0; i <= V_ng_ID_hmask; i++) {
2682 			LIST_FOREACH(node, &V_ng_ID_hash[i], nd_idnodes) {
2683 				struct nodeinfo *const np =
2684 				    &nl->nodeinfo[nl->numnames];
2685 
2686 				if (NG_NODE_NOT_VALID(node))
2687 					continue;
2688 				if (NG_NODE_HAS_NAME(node))
2689 					strcpy(np->name, NG_NODE_NAME(node));
2690 				strcpy(np->type, node->nd_type->name);
2691 				np->id = ng_node2ID(node);
2692 				np->hooks = node->nd_numhooks;
2693 				KASSERT(nl->numnames < V_ng_nodes,
2694 				    ("%s: no space", __func__));
2695 				nl->numnames++;
2696 			}
2697 		}
2698 		IDHASH_RUNLOCK();
2699 		break;
2700 	    }
2701 	case NGM_LISTNAMES:
2702 	    {
2703 		struct namelist *nl;
2704 		node_p node;
2705 		int i;
2706 
2707 		NAMEHASH_RLOCK();
2708 		/* Get response struct. */
2709 		NG_MKRESPONSE(resp, msg, sizeof(*nl) +
2710 		    (V_ng_named_nodes * sizeof(struct nodeinfo)), M_NOWAIT);
2711 		if (resp == NULL) {
2712 			NAMEHASH_RUNLOCK();
2713 			error = ENOMEM;
2714 			break;
2715 		}
2716 		nl = (struct namelist *) resp->data;
2717 
2718 		/* Cycle through the lists of nodes. */
2719 		nl->numnames = 0;
2720 		for (i = 0; i <= V_ng_name_hmask; i++) {
2721 			LIST_FOREACH(node, &V_ng_name_hash[i], nd_nodes) {
2722 				struct nodeinfo *const np =
2723 				    &nl->nodeinfo[nl->numnames];
2724 
2725 				if (NG_NODE_NOT_VALID(node))
2726 					continue;
2727 				strcpy(np->name, NG_NODE_NAME(node));
2728 				strcpy(np->type, node->nd_type->name);
2729 				np->id = ng_node2ID(node);
2730 				np->hooks = node->nd_numhooks;
2731 				KASSERT(nl->numnames < V_ng_named_nodes,
2732 				    ("%s: no space", __func__));
2733 				nl->numnames++;
2734 			}
2735 		}
2736 		NAMEHASH_RUNLOCK();
2737 		break;
2738 	    }
2739 
2740 	case NGM_LISTTYPES:
2741 	    {
2742 		struct typelist *tl;
2743 		struct ng_type *type;
2744 		int num = 0;
2745 
2746 		TYPELIST_RLOCK();
2747 		/* Count number of types */
2748 		LIST_FOREACH(type, &ng_typelist, types)
2749 			num++;
2750 
2751 		/* Get response struct */
2752 		NG_MKRESPONSE(resp, msg, sizeof(*tl) +
2753 		    (num * sizeof(struct typeinfo)), M_NOWAIT);
2754 		if (resp == NULL) {
2755 			TYPELIST_RUNLOCK();
2756 			error = ENOMEM;
2757 			break;
2758 		}
2759 		tl = (struct typelist *) resp->data;
2760 
2761 		/* Cycle through the linked list of types */
2762 		tl->numtypes = 0;
2763 		LIST_FOREACH(type, &ng_typelist, types) {
2764 			struct typeinfo *const tp = &tl->typeinfo[tl->numtypes];
2765 
2766 			strcpy(tp->type_name, type->name);
2767 			tp->numnodes = type->refs - 1; /* don't count list */
2768 			KASSERT(tl->numtypes < num, ("%s: no space", __func__));
2769 			tl->numtypes++;
2770 		}
2771 		TYPELIST_RUNLOCK();
2772 		break;
2773 	    }
2774 
2775 	case NGM_BINARY2ASCII:
2776 	    {
2777 		int bufSize = 1024;
2778 		const struct ng_parse_type *argstype;
2779 		const struct ng_cmdlist *c;
2780 		struct ng_mesg *binary, *ascii;
2781 
2782 		/* Data area must contain a valid netgraph message */
2783 		binary = (struct ng_mesg *)msg->data;
2784 		if (msg->header.arglen < sizeof(struct ng_mesg) ||
2785 		    (msg->header.arglen - sizeof(struct ng_mesg) <
2786 		    binary->header.arglen)) {
2787 			TRAP_ERROR();
2788 			error = EINVAL;
2789 			break;
2790 		}
2791 retry_b2a:
2792 		/* Get a response message with lots of room */
2793 		NG_MKRESPONSE(resp, msg, sizeof(*ascii) + bufSize, M_NOWAIT);
2794 		if (resp == NULL) {
2795 			error = ENOMEM;
2796 			break;
2797 		}
2798 		ascii = (struct ng_mesg *)resp->data;
2799 
2800 		/* Copy binary message header to response message payload */
2801 		bcopy(binary, ascii, sizeof(*binary));
2802 
2803 		/* Find command by matching typecookie and command number */
2804 		for (c = here->nd_type->cmdlist; c != NULL && c->name != NULL;
2805 		    c++) {
2806 			if (binary->header.typecookie == c->cookie &&
2807 			    binary->header.cmd == c->cmd)
2808 				break;
2809 		}
2810 		if (c == NULL || c->name == NULL) {
2811 			for (c = ng_generic_cmds; c->name != NULL; c++) {
2812 				if (binary->header.typecookie == c->cookie &&
2813 				    binary->header.cmd == c->cmd)
2814 					break;
2815 			}
2816 			if (c->name == NULL) {
2817 				NG_FREE_MSG(resp);
2818 				error = ENOSYS;
2819 				break;
2820 			}
2821 		}
2822 
2823 		/* Convert command name to ASCII */
2824 		snprintf(ascii->header.cmdstr, sizeof(ascii->header.cmdstr),
2825 		    "%s", c->name);
2826 
2827 		/* Convert command arguments to ASCII */
2828 		argstype = (binary->header.flags & NGF_RESP) ?
2829 		    c->respType : c->mesgType;
2830 		if (argstype == NULL) {
2831 			*ascii->data = '\0';
2832 		} else {
2833 			error = ng_unparse(argstype, (u_char *)binary->data,
2834 			    ascii->data, bufSize);
2835 			if (error == ERANGE) {
2836 				NG_FREE_MSG(resp);
2837 				bufSize *= 2;
2838 				goto retry_b2a;
2839 			} else if (error) {
2840 				NG_FREE_MSG(resp);
2841 				break;
2842 			}
2843 		}
2844 
2845 		/* Return the result as struct ng_mesg plus ASCII string */
2846 		bufSize = strlen(ascii->data) + 1;
2847 		ascii->header.arglen = bufSize;
2848 		resp->header.arglen = sizeof(*ascii) + bufSize;
2849 		break;
2850 	    }
2851 
2852 	case NGM_ASCII2BINARY:
2853 	    {
2854 		int bufSize = 20 * 1024;	/* XXX hard coded constant */
2855 		const struct ng_cmdlist *c;
2856 		const struct ng_parse_type *argstype;
2857 		struct ng_mesg *ascii, *binary;
2858 		int off = 0;
2859 
2860 		/* Data area must contain at least a struct ng_mesg + '\0' */
2861 		ascii = (struct ng_mesg *)msg->data;
2862 		if ((msg->header.arglen < sizeof(*ascii) + 1) ||
2863 		    (ascii->header.arglen < 1) ||
2864 		    (msg->header.arglen < sizeof(*ascii) +
2865 		    ascii->header.arglen)) {
2866 			TRAP_ERROR();
2867 			error = EINVAL;
2868 			break;
2869 		}
2870 		ascii->data[ascii->header.arglen - 1] = '\0';
2871 
2872 		/* Get a response message with lots of room */
2873 		NG_MKRESPONSE(resp, msg, sizeof(*binary) + bufSize, M_NOWAIT);
2874 		if (resp == NULL) {
2875 			error = ENOMEM;
2876 			break;
2877 		}
2878 		binary = (struct ng_mesg *)resp->data;
2879 
2880 		/* Copy ASCII message header to response message payload */
2881 		bcopy(ascii, binary, sizeof(*ascii));
2882 
2883 		/* Find command by matching ASCII command string */
2884 		for (c = here->nd_type->cmdlist;
2885 		    c != NULL && c->name != NULL; c++) {
2886 			if (strcmp(ascii->header.cmdstr, c->name) == 0)
2887 				break;
2888 		}
2889 		if (c == NULL || c->name == NULL) {
2890 			for (c = ng_generic_cmds; c->name != NULL; c++) {
2891 				if (strcmp(ascii->header.cmdstr, c->name) == 0)
2892 					break;
2893 			}
2894 			if (c->name == NULL) {
2895 				NG_FREE_MSG(resp);
2896 				error = ENOSYS;
2897 				break;
2898 			}
2899 		}
2900 
2901 		/* Convert command name to binary */
2902 		binary->header.cmd = c->cmd;
2903 		binary->header.typecookie = c->cookie;
2904 
2905 		/* Convert command arguments to binary */
2906 		argstype = (binary->header.flags & NGF_RESP) ?
2907 		    c->respType : c->mesgType;
2908 		if (argstype == NULL) {
2909 			bufSize = 0;
2910 		} else {
2911 			if ((error = ng_parse(argstype, ascii->data, &off,
2912 			    (u_char *)binary->data, &bufSize)) != 0) {
2913 				NG_FREE_MSG(resp);
2914 				break;
2915 			}
2916 		}
2917 
2918 		/* Return the result */
2919 		binary->header.arglen = bufSize;
2920 		resp->header.arglen = sizeof(*binary) + bufSize;
2921 		break;
2922 	    }
2923 
2924 	case NGM_TEXT_CONFIG:
2925 	case NGM_TEXT_STATUS:
2926 		/*
2927 		 * This one is tricky as it passes the command down to the
2928 		 * actual node, even though it is a generic type command.
2929 		 * This means we must assume that the item/msg is already freed
2930 		 * when control passes back to us.
2931 		 */
2932 		if (here->nd_type->rcvmsg != NULL) {
2933 			NGI_MSG(item) = msg; /* put it back as we found it */
2934 			return((*here->nd_type->rcvmsg)(here, item, lasthook));
2935 		}
2936 		/* Fall through if rcvmsg not supported */
2937 	default:
2938 		TRAP_ERROR();
2939 		error = EINVAL;
2940 	}
2941 	/*
2942 	 * Sometimes a generic message may be statically allocated
2943 	 * to avoid problems with allocating when in tight memory situations.
2944 	 * Don't free it if it is so.
2945 	 * I break them apart here, because erros may cause a free if the item
2946 	 * in which case we'd be doing it twice.
2947 	 * they are kept together above, to simplify freeing.
2948 	 */
2949 out:
2950 	NG_RESPOND_MSG(error, here, item, resp);
2951 	NG_FREE_MSG(msg);
2952 	return (error);
2953 }
2954 
2955 /************************************************************************
2956 			Queue element get/free routines
2957 ************************************************************************/
2958 
2959 uma_zone_t			ng_qzone;
2960 uma_zone_t			ng_qdzone;
2961 static int			numthreads = 0; /* number of queue threads */
2962 static int			maxalloc = 4096;/* limit the damage of a leak */
2963 static int			maxdata = 4096;	/* limit the damage of a DoS */
2964 
2965 SYSCTL_INT(_net_graph, OID_AUTO, threads, CTLFLAG_RDTUN, &numthreads,
2966     0, "Number of queue processing threads");
2967 SYSCTL_INT(_net_graph, OID_AUTO, maxalloc, CTLFLAG_RDTUN, &maxalloc,
2968     0, "Maximum number of non-data queue items to allocate");
2969 SYSCTL_INT(_net_graph, OID_AUTO, maxdata, CTLFLAG_RDTUN, &maxdata,
2970     0, "Maximum number of data queue items to allocate");
2971 
2972 #ifdef	NETGRAPH_DEBUG
2973 static TAILQ_HEAD(, ng_item) ng_itemlist = TAILQ_HEAD_INITIALIZER(ng_itemlist);
2974 static int allocated;	/* number of items malloc'd */
2975 #endif
2976 
2977 /*
2978  * Get a queue entry.
2979  * This is usually called when a packet first enters netgraph.
2980  * By definition, this is usually from an interrupt, or from a user.
2981  * Users are not so important, but try be quick for the times that it's
2982  * an interrupt.
2983  */
2984 static __inline item_p
2985 ng_alloc_item(int type, int flags)
2986 {
2987 	item_p item;
2988 
2989 	KASSERT(((type & ~NGQF_TYPE) == 0),
2990 	    ("%s: incorrect item type: %d", __func__, type));
2991 
2992 	item = uma_zalloc((type == NGQF_DATA) ? ng_qdzone : ng_qzone,
2993 	    ((flags & NG_WAITOK) ? M_WAITOK : M_NOWAIT) | M_ZERO);
2994 
2995 	if (item) {
2996 		item->el_flags = type;
2997 #ifdef	NETGRAPH_DEBUG
2998 		mtx_lock(&ngq_mtx);
2999 		TAILQ_INSERT_TAIL(&ng_itemlist, item, all);
3000 		allocated++;
3001 		mtx_unlock(&ngq_mtx);
3002 #endif
3003 	}
3004 
3005 	return (item);
3006 }
3007 
3008 /*
3009  * Release a queue entry
3010  */
3011 void
3012 ng_free_item(item_p item)
3013 {
3014 	/*
3015 	 * The item may hold resources on its own. We need to free
3016 	 * these before we can free the item. What they are depends upon
3017 	 * what kind of item it is. it is important that nodes zero
3018 	 * out pointers to resources that they remove from the item
3019 	 * or we release them again here.
3020 	 */
3021 	switch (item->el_flags & NGQF_TYPE) {
3022 	case NGQF_DATA:
3023 		/* If we have an mbuf still attached.. */
3024 		NG_FREE_M(_NGI_M(item));
3025 		break;
3026 	case NGQF_MESG:
3027 		_NGI_RETADDR(item) = 0;
3028 		NG_FREE_MSG(_NGI_MSG(item));
3029 		break;
3030 	case NGQF_FN:
3031 	case NGQF_FN2:
3032 		/* nothing to free really, */
3033 		_NGI_FN(item) = NULL;
3034 		_NGI_ARG1(item) = NULL;
3035 		_NGI_ARG2(item) = 0;
3036 		break;
3037 	}
3038 	/* If we still have a node or hook referenced... */
3039 	_NGI_CLR_NODE(item);
3040 	_NGI_CLR_HOOK(item);
3041 
3042 #ifdef	NETGRAPH_DEBUG
3043 	mtx_lock(&ngq_mtx);
3044 	TAILQ_REMOVE(&ng_itemlist, item, all);
3045 	allocated--;
3046 	mtx_unlock(&ngq_mtx);
3047 #endif
3048 	uma_zfree(((item->el_flags & NGQF_TYPE) == NGQF_DATA) ?
3049 	    ng_qdzone : ng_qzone, item);
3050 }
3051 
3052 /*
3053  * Change type of the queue entry.
3054  * Possibly reallocates it from another UMA zone.
3055  */
3056 static __inline item_p
3057 ng_realloc_item(item_p pitem, int type, int flags)
3058 {
3059 	item_p item;
3060 	int from, to;
3061 
3062 	KASSERT((pitem != NULL), ("%s: can't reallocate NULL", __func__));
3063 	KASSERT(((type & ~NGQF_TYPE) == 0),
3064 	    ("%s: incorrect item type: %d", __func__, type));
3065 
3066 	from = ((pitem->el_flags & NGQF_TYPE) == NGQF_DATA);
3067 	to = (type == NGQF_DATA);
3068 	if (from != to) {
3069 		/* If reallocation is required do it and copy item. */
3070 		if ((item = ng_alloc_item(type, flags)) == NULL) {
3071 			ng_free_item(pitem);
3072 			return (NULL);
3073 		}
3074 		*item = *pitem;
3075 		ng_free_item(pitem);
3076 	} else
3077 		item = pitem;
3078 	item->el_flags = (item->el_flags & ~NGQF_TYPE) | type;
3079 
3080 	return (item);
3081 }
3082 
3083 /************************************************************************
3084 			Module routines
3085 ************************************************************************/
3086 
3087 /*
3088  * Handle the loading/unloading of a netgraph node type module
3089  */
3090 int
3091 ng_mod_event(module_t mod, int event, void *data)
3092 {
3093 	struct ng_type *const type = data;
3094 	int error = 0;
3095 
3096 	switch (event) {
3097 	case MOD_LOAD:
3098 
3099 		/* Register new netgraph node type */
3100 		if ((error = ng_newtype(type)) != 0)
3101 			break;
3102 
3103 		/* Call type specific code */
3104 		if (type->mod_event != NULL)
3105 			if ((error = (*type->mod_event)(mod, event, data))) {
3106 				TYPELIST_WLOCK();
3107 				type->refs--;	/* undo it */
3108 				LIST_REMOVE(type, types);
3109 				TYPELIST_WUNLOCK();
3110 			}
3111 		break;
3112 
3113 	case MOD_UNLOAD:
3114 		if (type->refs > 1) {		/* make sure no nodes exist! */
3115 			error = EBUSY;
3116 		} else {
3117 			if (type->refs == 0) /* failed load, nothing to undo */
3118 				break;
3119 			if (type->mod_event != NULL) {	/* check with type */
3120 				error = (*type->mod_event)(mod, event, data);
3121 				if (error != 0)	/* type refuses.. */
3122 					break;
3123 			}
3124 			TYPELIST_WLOCK();
3125 			LIST_REMOVE(type, types);
3126 			TYPELIST_WUNLOCK();
3127 		}
3128 		break;
3129 
3130 	default:
3131 		if (type->mod_event != NULL)
3132 			error = (*type->mod_event)(mod, event, data);
3133 		else
3134 			error = EOPNOTSUPP;		/* XXX ? */
3135 		break;
3136 	}
3137 	return (error);
3138 }
3139 
3140 static void
3141 vnet_netgraph_init(const void *unused __unused)
3142 {
3143 
3144 	/* We start with small hashes, but they can grow. */
3145 	V_ng_ID_hash = hashinit(16, M_NETGRAPH_NODE, &V_ng_ID_hmask);
3146 	V_ng_name_hash = hashinit(16, M_NETGRAPH_NODE, &V_ng_name_hmask);
3147 }
3148 VNET_SYSINIT(vnet_netgraph_init, SI_SUB_NETGRAPH, SI_ORDER_FIRST,
3149     vnet_netgraph_init, NULL);
3150 
3151 #ifdef VIMAGE
3152 static void
3153 vnet_netgraph_uninit(const void *unused __unused)
3154 {
3155 	node_p node = NULL, last_killed = NULL;
3156 	int i;
3157 
3158 	do {
3159 		/* Find a node to kill */
3160 		IDHASH_RLOCK();
3161 		for (i = 0; i <= V_ng_ID_hmask; i++) {
3162 			LIST_FOREACH(node, &V_ng_ID_hash[i], nd_idnodes) {
3163 				if (node != &ng_deadnode) {
3164 					NG_NODE_REF(node);
3165 					break;
3166 				}
3167 			}
3168 			if (node != NULL)
3169 				break;
3170 		}
3171 		IDHASH_RUNLOCK();
3172 
3173 		/* Attempt to kill it only if it is a regular node */
3174 		if (node != NULL) {
3175 			if (node == last_killed) {
3176 				if (node->nd_flags & NGF_REALLY_DIE)
3177 					panic("ng node %s won't die",
3178 					    node->nd_name);
3179 				/* The node persisted itself.  Try again. */
3180 				node->nd_flags |= NGF_REALLY_DIE;
3181 			}
3182 			ng_rmnode(node, NULL, NULL, 0);
3183 			NG_NODE_UNREF(node);
3184 			last_killed = node;
3185 		}
3186 	} while (node != NULL);
3187 
3188 	hashdestroy(V_ng_name_hash, M_NETGRAPH_NODE, V_ng_name_hmask);
3189 	hashdestroy(V_ng_ID_hash, M_NETGRAPH_NODE, V_ng_ID_hmask);
3190 }
3191 VNET_SYSUNINIT(vnet_netgraph_uninit, SI_SUB_NETGRAPH, SI_ORDER_FIRST,
3192     vnet_netgraph_uninit, NULL);
3193 #endif /* VIMAGE */
3194 
3195 /*
3196  * Handle loading and unloading for this code.
3197  * The only thing we need to link into is the NETISR strucure.
3198  */
3199 static int
3200 ngb_mod_event(module_t mod, int event, void *data)
3201 {
3202 	struct proc *p;
3203 	struct thread *td;
3204 	int i, error = 0;
3205 
3206 	switch (event) {
3207 	case MOD_LOAD:
3208 		/* Initialize everything. */
3209 		NG_WORKLIST_LOCK_INIT();
3210 		rw_init(&ng_typelist_lock, "netgraph types");
3211 		rw_init(&ng_idhash_lock, "netgraph idhash");
3212 		rw_init(&ng_namehash_lock, "netgraph namehash");
3213 		rw_init(&ng_topo_lock, "netgraph topology mutex");
3214 #ifdef	NETGRAPH_DEBUG
3215 		mtx_init(&ng_nodelist_mtx, "netgraph nodelist mutex", NULL,
3216 		    MTX_DEF);
3217 		mtx_init(&ngq_mtx, "netgraph item list mutex", NULL,
3218 		    MTX_DEF);
3219 #endif
3220 		ng_qzone = uma_zcreate("NetGraph items", sizeof(struct ng_item),
3221 		    NULL, NULL, NULL, NULL, UMA_ALIGN_CACHE, 0);
3222 		uma_zone_set_max(ng_qzone, maxalloc);
3223 		ng_qdzone = uma_zcreate("NetGraph data items",
3224 		    sizeof(struct ng_item), NULL, NULL, NULL, NULL,
3225 		    UMA_ALIGN_CACHE, 0);
3226 		uma_zone_set_max(ng_qdzone, maxdata);
3227 		/* Autoconfigure number of threads. */
3228 		if (numthreads <= 0)
3229 			numthreads = mp_ncpus;
3230 		/* Create threads. */
3231     		p = NULL; /* start with no process */
3232 		for (i = 0; i < numthreads; i++) {
3233 			if (kproc_kthread_add(ngthread, NULL, &p, &td,
3234 			    RFHIGHPID, 0, "ng_queue", "ng_queue%d", i)) {
3235 				numthreads = i;
3236 				break;
3237 			}
3238 		}
3239 		break;
3240 	case MOD_UNLOAD:
3241 		/* You can't unload it because an interface may be using it. */
3242 		error = EBUSY;
3243 		break;
3244 	default:
3245 		error = EOPNOTSUPP;
3246 		break;
3247 	}
3248 	return (error);
3249 }
3250 
3251 static moduledata_t netgraph_mod = {
3252 	"netgraph",
3253 	ngb_mod_event,
3254 	(NULL)
3255 };
3256 DECLARE_MODULE(netgraph, netgraph_mod, SI_SUB_NETGRAPH, SI_ORDER_FIRST);
3257 SYSCTL_NODE(_net, OID_AUTO, graph, CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
3258     "netgraph Family");
3259 SYSCTL_INT(_net_graph, OID_AUTO, abi_version, CTLFLAG_RD, SYSCTL_NULL_INT_PTR, NG_ABI_VERSION,"");
3260 SYSCTL_INT(_net_graph, OID_AUTO, msg_version, CTLFLAG_RD, SYSCTL_NULL_INT_PTR, NG_VERSION, "");
3261 
3262 #ifdef	NETGRAPH_DEBUG
3263 void
3264 dumphook (hook_p hook, char *file, int line)
3265 {
3266 	printf("hook: name %s, %d refs, Last touched:\n",
3267 		_NG_HOOK_NAME(hook), hook->hk_refs);
3268 	printf("	Last active @ %s, line %d\n",
3269 		hook->lastfile, hook->lastline);
3270 	if (line) {
3271 		printf(" problem discovered at file %s, line %d\n", file, line);
3272 #ifdef KDB
3273 		kdb_backtrace();
3274 #endif
3275 	}
3276 }
3277 
3278 void
3279 dumpnode(node_p node, char *file, int line)
3280 {
3281 	printf("node: ID [%x]: type '%s', %d hooks, flags 0x%x, %d refs, %s:\n",
3282 		_NG_NODE_ID(node), node->nd_type->name,
3283 		node->nd_numhooks, node->nd_flags,
3284 		node->nd_refs, node->nd_name);
3285 	printf("	Last active @ %s, line %d\n",
3286 		node->lastfile, node->lastline);
3287 	if (line) {
3288 		printf(" problem discovered at file %s, line %d\n", file, line);
3289 #ifdef KDB
3290 		kdb_backtrace();
3291 #endif
3292 	}
3293 }
3294 
3295 void
3296 dumpitem(item_p item, char *file, int line)
3297 {
3298 	printf(" ACTIVE item, last used at %s, line %d",
3299 		item->lastfile, item->lastline);
3300 	switch(item->el_flags & NGQF_TYPE) {
3301 	case NGQF_DATA:
3302 		printf(" - [data]\n");
3303 		break;
3304 	case NGQF_MESG:
3305 		printf(" - retaddr[%d]:\n", _NGI_RETADDR(item));
3306 		break;
3307 	case NGQF_FN:
3308 		printf(" - fn@%p (%p, %p, %p, %d (%x))\n",
3309 			_NGI_FN(item),
3310 			_NGI_NODE(item),
3311 			_NGI_HOOK(item),
3312 			item->body.fn.fn_arg1,
3313 			item->body.fn.fn_arg2,
3314 			item->body.fn.fn_arg2);
3315 		break;
3316 	case NGQF_FN2:
3317 		printf(" - fn2@%p (%p, %p, %p, %d (%x))\n",
3318 			_NGI_FN2(item),
3319 			_NGI_NODE(item),
3320 			_NGI_HOOK(item),
3321 			item->body.fn.fn_arg1,
3322 			item->body.fn.fn_arg2,
3323 			item->body.fn.fn_arg2);
3324 		break;
3325 	}
3326 	if (line) {
3327 		printf(" problem discovered at file %s, line %d\n", file, line);
3328 		if (_NGI_NODE(item)) {
3329 			printf("node %p ([%x])\n",
3330 				_NGI_NODE(item), ng_node2ID(_NGI_NODE(item)));
3331 		}
3332 	}
3333 }
3334 
3335 static void
3336 ng_dumpitems(void)
3337 {
3338 	item_p item;
3339 	int i = 1;
3340 	TAILQ_FOREACH(item, &ng_itemlist, all) {
3341 		printf("[%d] ", i++);
3342 		dumpitem(item, NULL, 0);
3343 	}
3344 }
3345 
3346 static void
3347 ng_dumpnodes(void)
3348 {
3349 	node_p node;
3350 	int i = 1;
3351 	mtx_lock(&ng_nodelist_mtx);
3352 	SLIST_FOREACH(node, &ng_allnodes, nd_all) {
3353 		printf("[%d] ", i++);
3354 		dumpnode(node, NULL, 0);
3355 	}
3356 	mtx_unlock(&ng_nodelist_mtx);
3357 }
3358 
3359 static void
3360 ng_dumphooks(void)
3361 {
3362 	hook_p hook;
3363 	int i = 1;
3364 	mtx_lock(&ng_nodelist_mtx);
3365 	SLIST_FOREACH(hook, &ng_allhooks, hk_all) {
3366 		printf("[%d] ", i++);
3367 		dumphook(hook, NULL, 0);
3368 	}
3369 	mtx_unlock(&ng_nodelist_mtx);
3370 }
3371 
3372 static int
3373 sysctl_debug_ng_dump_items(SYSCTL_HANDLER_ARGS)
3374 {
3375 	int error;
3376 	int val;
3377 
3378 	val = allocated;
3379 	error = sysctl_handle_int(oidp, &val, 0, req);
3380 	if (error != 0 || req->newptr == NULL)
3381 		return (error);
3382 	if (val == 42) {
3383 		ng_dumpitems();
3384 		ng_dumpnodes();
3385 		ng_dumphooks();
3386 	}
3387 	return (0);
3388 }
3389 
3390 SYSCTL_PROC(_debug, OID_AUTO, ng_dump_items,
3391     CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_MPSAFE, 0, sizeof(int),
3392     sysctl_debug_ng_dump_items, "I",
3393     "Number of allocated items");
3394 #endif	/* NETGRAPH_DEBUG */
3395 
3396 /***********************************************************************
3397 * Worklist routines
3398 **********************************************************************/
3399 /*
3400  * Pick a node off the list of nodes with work,
3401  * try get an item to process off it. Remove the node from the list.
3402  */
3403 static void
3404 ngthread(void *arg)
3405 {
3406 	for (;;) {
3407 		struct epoch_tracker et;
3408 		node_p  node;
3409 
3410 		/* Get node from the worklist. */
3411 		NG_WORKLIST_LOCK();
3412 		while ((node = STAILQ_FIRST(&ng_worklist)) == NULL)
3413 			NG_WORKLIST_SLEEP();
3414 		STAILQ_REMOVE_HEAD(&ng_worklist, nd_input_queue.q_work);
3415 		NG_WORKLIST_UNLOCK();
3416 		CURVNET_SET(node->nd_vnet);
3417 		CTR3(KTR_NET, "%20s: node [%x] (%p) taken off worklist",
3418 		    __func__, node->nd_ID, node);
3419 		/*
3420 		 * We have the node. We also take over the reference
3421 		 * that the list had on it.
3422 		 * Now process as much as you can, until it won't
3423 		 * let you have another item off the queue.
3424 		 * All this time, keep the reference
3425 		 * that lets us be sure that the node still exists.
3426 		 * Let the reference go at the last minute.
3427 		 */
3428 		NET_EPOCH_ENTER(et);
3429 		for (;;) {
3430 			item_p item;
3431 			int rw;
3432 
3433 			NG_QUEUE_LOCK(&node->nd_input_queue);
3434 			item = ng_dequeue(node, &rw);
3435 			if (item == NULL) {
3436 				node->nd_input_queue.q_flags2 &= ~NGQ2_WORKQ;
3437 				NG_QUEUE_UNLOCK(&node->nd_input_queue);
3438 				break; /* go look for another node */
3439 			} else {
3440 				NG_QUEUE_UNLOCK(&node->nd_input_queue);
3441 				NGI_GET_NODE(item, node); /* zaps stored node */
3442 				ng_apply_item(node, item, rw);
3443 				NG_NODE_UNREF(node);
3444 			}
3445 		}
3446 		NET_EPOCH_EXIT(et);
3447 		NG_NODE_UNREF(node);
3448 		CURVNET_RESTORE();
3449 	}
3450 }
3451 
3452 /*
3453  * XXX
3454  * It's possible that a debugging NG_NODE_REF may need
3455  * to be outside the mutex zone
3456  */
3457 static void
3458 ng_worklist_add(node_p node)
3459 {
3460 
3461 	mtx_assert(&node->nd_input_queue.q_mtx, MA_OWNED);
3462 
3463 	if ((node->nd_input_queue.q_flags2 & NGQ2_WORKQ) == 0) {
3464 		/*
3465 		 * If we are not already on the work queue,
3466 		 * then put us on.
3467 		 */
3468 		node->nd_input_queue.q_flags2 |= NGQ2_WORKQ;
3469 		NG_NODE_REF(node); /* XXX safe in mutex? */
3470 		NG_WORKLIST_LOCK();
3471 		STAILQ_INSERT_TAIL(&ng_worklist, node, nd_input_queue.q_work);
3472 		NG_WORKLIST_UNLOCK();
3473 		CTR3(KTR_NET, "%20s: node [%x] (%p) put on worklist", __func__,
3474 		    node->nd_ID, node);
3475 		NG_WORKLIST_WAKEUP();
3476 	} else {
3477 		CTR3(KTR_NET, "%20s: node [%x] (%p) already on worklist",
3478 		    __func__, node->nd_ID, node);
3479 	}
3480 }
3481 
3482 /***********************************************************************
3483 * Externally useable functions to set up a queue item ready for sending
3484 ***********************************************************************/
3485 
3486 #ifdef	NETGRAPH_DEBUG
3487 #define	ITEM_DEBUG_CHECKS						\
3488 	do {								\
3489 		if (NGI_NODE(item) ) {					\
3490 			printf("item already has node");		\
3491 			kdb_enter(KDB_WHY_NETGRAPH, "has node");	\
3492 			NGI_CLR_NODE(item);				\
3493 		}							\
3494 		if (NGI_HOOK(item) ) {					\
3495 			printf("item already has hook");		\
3496 			kdb_enter(KDB_WHY_NETGRAPH, "has hook");	\
3497 			NGI_CLR_HOOK(item);				\
3498 		}							\
3499 	} while (0)
3500 #else
3501 #define ITEM_DEBUG_CHECKS
3502 #endif
3503 
3504 /*
3505  * Put mbuf into the item.
3506  * Hook and node references will be removed when the item is dequeued.
3507  * (or equivalent)
3508  * (XXX) Unsafe because no reference held by peer on remote node.
3509  * remote node might go away in this timescale.
3510  * We know the hooks can't go away because that would require getting
3511  * a writer item on both nodes and we must have at least a  reader
3512  * here to be able to do this.
3513  * Note that the hook loaded is the REMOTE hook.
3514  *
3515  * This is possibly in the critical path for new data.
3516  */
3517 item_p
3518 ng_package_data(struct mbuf *m, int flags)
3519 {
3520 	item_p item;
3521 
3522 	if ((item = ng_alloc_item(NGQF_DATA, flags)) == NULL) {
3523 		NG_FREE_M(m);
3524 		return (NULL);
3525 	}
3526 	ITEM_DEBUG_CHECKS;
3527 	item->el_flags |= NGQF_READER;
3528 	NGI_M(item) = m;
3529 	return (item);
3530 }
3531 
3532 /*
3533  * Allocate a queue item and put items into it..
3534  * Evaluate the address as this will be needed to queue it and
3535  * to work out what some of the fields should be.
3536  * Hook and node references will be removed when the item is dequeued.
3537  * (or equivalent)
3538  */
3539 item_p
3540 ng_package_msg(struct ng_mesg *msg, int flags)
3541 {
3542 	item_p item;
3543 
3544 	if ((item = ng_alloc_item(NGQF_MESG, flags)) == NULL) {
3545 		NG_FREE_MSG(msg);
3546 		return (NULL);
3547 	}
3548 	ITEM_DEBUG_CHECKS;
3549 	/* Messages items count as writers unless explicitly exempted. */
3550 	if (msg->header.cmd & NGM_READONLY)
3551 		item->el_flags |= NGQF_READER;
3552 	else
3553 		item->el_flags |= NGQF_WRITER;
3554 	/*
3555 	 * Set the current lasthook into the queue item
3556 	 */
3557 	NGI_MSG(item) = msg;
3558 	NGI_RETADDR(item) = 0;
3559 	return (item);
3560 }
3561 
3562 #define SET_RETADDR(item, here, retaddr)				\
3563 	do {	/* Data or fn items don't have retaddrs */		\
3564 		if ((item->el_flags & NGQF_TYPE) == NGQF_MESG) {	\
3565 			if (retaddr) {					\
3566 				NGI_RETADDR(item) = retaddr;		\
3567 			} else {					\
3568 				/*					\
3569 				 * The old return address should be ok.	\
3570 				 * If there isn't one, use the address	\
3571 				 * here.				\
3572 				 */					\
3573 				if (NGI_RETADDR(item) == 0) {		\
3574 					NGI_RETADDR(item)		\
3575 						= ng_node2ID(here);	\
3576 				}					\
3577 			}						\
3578 		}							\
3579 	} while (0)
3580 
3581 int
3582 ng_address_hook(node_p here, item_p item, hook_p hook, ng_ID_t retaddr)
3583 {
3584 	hook_p peer;
3585 	node_p peernode;
3586 	ITEM_DEBUG_CHECKS;
3587 	/*
3588 	 * Quick sanity check..
3589 	 * Since a hook holds a reference on its node, once we know
3590 	 * that the peer is still connected (even if invalid,) we know
3591 	 * that the peer node is present, though maybe invalid.
3592 	 */
3593 	TOPOLOGY_RLOCK();
3594 	if ((hook == NULL) || NG_HOOK_NOT_VALID(hook) ||
3595 	    NG_HOOK_NOT_VALID(peer = NG_HOOK_PEER(hook)) ||
3596 	    NG_NODE_NOT_VALID(peernode = NG_PEER_NODE(hook))) {
3597 		NG_FREE_ITEM(item);
3598 		TRAP_ERROR();
3599 		TOPOLOGY_RUNLOCK();
3600 		return (ENETDOWN);
3601 	}
3602 
3603 	/*
3604 	 * Transfer our interest to the other (peer) end.
3605 	 */
3606 	NG_HOOK_REF(peer);
3607 	NG_NODE_REF(peernode);
3608 	NGI_SET_HOOK(item, peer);
3609 	NGI_SET_NODE(item, peernode);
3610 	SET_RETADDR(item, here, retaddr);
3611 
3612 	TOPOLOGY_RUNLOCK();
3613 
3614 	return (0);
3615 }
3616 
3617 int
3618 ng_address_path(node_p here, item_p item, const char *address, ng_ID_t retaddr)
3619 {
3620 	node_p	dest = NULL;
3621 	hook_p	hook = NULL;
3622 	int	error;
3623 
3624 	ITEM_DEBUG_CHECKS;
3625 	/*
3626 	 * Note that ng_path2noderef increments the reference count
3627 	 * on the node for us if it finds one. So we don't have to.
3628 	 */
3629 	error = ng_path2noderef(here, address, &dest, &hook);
3630 	if (error) {
3631 		NG_FREE_ITEM(item);
3632 		return (error);
3633 	}
3634 	NGI_SET_NODE(item, dest);
3635 	if (hook)
3636 		NGI_SET_HOOK(item, hook);
3637 
3638 	SET_RETADDR(item, here, retaddr);
3639 	return (0);
3640 }
3641 
3642 int
3643 ng_address_ID(node_p here, item_p item, ng_ID_t ID, ng_ID_t retaddr)
3644 {
3645 	node_p dest;
3646 
3647 	ITEM_DEBUG_CHECKS;
3648 	/*
3649 	 * Find the target node.
3650 	 */
3651 	dest = ng_ID2noderef(ID); /* GETS REFERENCE! */
3652 	if (dest == NULL) {
3653 		NG_FREE_ITEM(item);
3654 		TRAP_ERROR();
3655 		return(EINVAL);
3656 	}
3657 	/* Fill out the contents */
3658 	NGI_SET_NODE(item, dest);
3659 	NGI_CLR_HOOK(item);
3660 	SET_RETADDR(item, here, retaddr);
3661 	return (0);
3662 }
3663 
3664 /*
3665  * special case to send a message to self (e.g. destroy node)
3666  * Possibly indicate an arrival hook too.
3667  * Useful for removing that hook :-)
3668  */
3669 item_p
3670 ng_package_msg_self(node_p here, hook_p hook, struct ng_mesg *msg)
3671 {
3672 	item_p item;
3673 
3674 	/*
3675 	 * Find the target node.
3676 	 * If there is a HOOK argument, then use that in preference
3677 	 * to the address.
3678 	 */
3679 	if ((item = ng_alloc_item(NGQF_MESG, NG_NOFLAGS)) == NULL) {
3680 		NG_FREE_MSG(msg);
3681 		return (NULL);
3682 	}
3683 
3684 	/* Fill out the contents */
3685 	item->el_flags |= NGQF_WRITER;
3686 	NG_NODE_REF(here);
3687 	NGI_SET_NODE(item, here);
3688 	if (hook) {
3689 		NG_HOOK_REF(hook);
3690 		NGI_SET_HOOK(item, hook);
3691 	}
3692 	NGI_MSG(item) = msg;
3693 	NGI_RETADDR(item) = ng_node2ID(here);
3694 	return (item);
3695 }
3696 
3697 /*
3698  * Send ng_item_fn function call to the specified node.
3699  */
3700 
3701 int
3702 ng_send_fn(node_p node, hook_p hook, ng_item_fn *fn, void * arg1, int arg2)
3703 {
3704 
3705 	return ng_send_fn1(node, hook, fn, arg1, arg2, NG_NOFLAGS);
3706 }
3707 
3708 int
3709 ng_send_fn1(node_p node, hook_p hook, ng_item_fn *fn, void * arg1, int arg2,
3710 	int flags)
3711 {
3712 	item_p item;
3713 
3714 	if ((item = ng_alloc_item(NGQF_FN, flags)) == NULL) {
3715 		return (ENOMEM);
3716 	}
3717 	item->el_flags |= NGQF_WRITER;
3718 	NG_NODE_REF(node); /* and one for the item */
3719 	NGI_SET_NODE(item, node);
3720 	if (hook) {
3721 		NG_HOOK_REF(hook);
3722 		NGI_SET_HOOK(item, hook);
3723 	}
3724 	NGI_FN(item) = fn;
3725 	NGI_ARG1(item) = arg1;
3726 	NGI_ARG2(item) = arg2;
3727 	return(ng_snd_item(item, flags));
3728 }
3729 
3730 /*
3731  * Send ng_item_fn2 function call to the specified node.
3732  *
3733  * If an optional pitem parameter is supplied, its apply
3734  * callback will be copied to the new item. If also NG_REUSE_ITEM
3735  * flag is set, no new item will be allocated, but pitem will
3736  * be used.
3737  */
3738 int
3739 ng_send_fn2(node_p node, hook_p hook, item_p pitem, ng_item_fn2 *fn, void *arg1,
3740 	int arg2, int flags)
3741 {
3742 	item_p item;
3743 
3744 	KASSERT((pitem != NULL || (flags & NG_REUSE_ITEM) == 0),
3745 	    ("%s: NG_REUSE_ITEM but no pitem", __func__));
3746 
3747 	/*
3748 	 * Allocate a new item if no supplied or
3749 	 * if we can't use supplied one.
3750 	 */
3751 	if (pitem == NULL || (flags & NG_REUSE_ITEM) == 0) {
3752 		if ((item = ng_alloc_item(NGQF_FN2, flags)) == NULL)
3753 			return (ENOMEM);
3754 		if (pitem != NULL)
3755 			item->apply = pitem->apply;
3756 	} else {
3757 		if ((item = ng_realloc_item(pitem, NGQF_FN2, flags)) == NULL)
3758 			return (ENOMEM);
3759 	}
3760 
3761 	item->el_flags = (item->el_flags & ~NGQF_RW) | NGQF_WRITER;
3762 	NG_NODE_REF(node); /* and one for the item */
3763 	NGI_SET_NODE(item, node);
3764 	if (hook) {
3765 		NG_HOOK_REF(hook);
3766 		NGI_SET_HOOK(item, hook);
3767 	}
3768 	NGI_FN2(item) = fn;
3769 	NGI_ARG1(item) = arg1;
3770 	NGI_ARG2(item) = arg2;
3771 	return(ng_snd_item(item, flags));
3772 }
3773 
3774 /*
3775  * Official timeout routines for Netgraph nodes.
3776  */
3777 static void
3778 ng_callout_trampoline(void *arg)
3779 {
3780 	struct epoch_tracker et;
3781 	item_p item = arg;
3782 
3783 	NET_EPOCH_ENTER(et);
3784 	CURVNET_SET(NGI_NODE(item)->nd_vnet);
3785 	ng_snd_item(item, 0);
3786 	CURVNET_RESTORE();
3787 	NET_EPOCH_EXIT(et);
3788 }
3789 
3790 int
3791 ng_callout(struct callout *c, node_p node, hook_p hook, int ticks,
3792     ng_item_fn *fn, void * arg1, int arg2)
3793 {
3794 	item_p item, oitem;
3795 
3796 	if ((item = ng_alloc_item(NGQF_FN, NG_NOFLAGS)) == NULL)
3797 		return (ENOMEM);
3798 
3799 	item->el_flags |= NGQF_WRITER;
3800 	NG_NODE_REF(node);		/* and one for the item */
3801 	NGI_SET_NODE(item, node);
3802 	if (hook) {
3803 		NG_HOOK_REF(hook);
3804 		NGI_SET_HOOK(item, hook);
3805 	}
3806 	NGI_FN(item) = fn;
3807 	NGI_ARG1(item) = arg1;
3808 	NGI_ARG2(item) = arg2;
3809 	oitem = c->c_arg;
3810 	if (callout_reset(c, ticks, &ng_callout_trampoline, item) == 1 &&
3811 	    oitem != NULL)
3812 		NG_FREE_ITEM(oitem);
3813 	return (0);
3814 }
3815 
3816 /*
3817  * Free references and item if callout_stop/callout_drain returned 1,
3818  * meaning that callout was successfully stopped and now references
3819  * belong to us.
3820  */
3821 static void
3822 ng_uncallout_internal(struct callout *c, node_p node)
3823 {
3824 	item_p item;
3825 
3826 	item = c->c_arg;
3827 	if ((c->c_func == &ng_callout_trampoline) &&
3828 	    (item != NULL) && (NGI_NODE(item) == node)) {
3829 		/*
3830 		 * We successfully removed it from the queue before it ran
3831 		 * So now we need to unreference everything that was
3832 		 * given extra references. (NG_FREE_ITEM does this).
3833 		 */
3834 		NG_FREE_ITEM(item);
3835 	}
3836 	c->c_arg = NULL;
3837 }
3838 
3839 
3840 /* A special modified version of callout_stop() */
3841 int
3842 ng_uncallout(struct callout *c, node_p node)
3843 {
3844 	int rval;
3845 
3846 	rval = callout_stop(c);
3847 	if (rval > 0)
3848 		/*
3849 		 * XXXGL: in case if callout is already running and next
3850 		 * invocation is scheduled at the same time, callout_stop()
3851 		 * returns 0. See d153eeee97d. In this case netgraph(4) would
3852 		 * leak resources. However, no nodes are known to induce such
3853 		 * behavior.
3854 		 */
3855 		ng_uncallout_internal(c, node);
3856 
3857 	return (rval);
3858 }
3859 
3860 /* A special modified version of callout_drain() */
3861 int
3862 ng_uncallout_drain(struct callout *c, node_p node)
3863 {
3864 	int rval;
3865 
3866 	rval = callout_drain(c);
3867 	if (rval > 0)
3868 		ng_uncallout_internal(c, node);
3869 
3870 	return (rval);
3871 }
3872 
3873 /*
3874  * Set the address, if none given, give the node here.
3875  */
3876 void
3877 ng_replace_retaddr(node_p here, item_p item, ng_ID_t retaddr)
3878 {
3879 	if (retaddr) {
3880 		NGI_RETADDR(item) = retaddr;
3881 	} else {
3882 		/*
3883 		 * The old return address should be ok.
3884 		 * If there isn't one, use the address here.
3885 		 */
3886 		NGI_RETADDR(item) = ng_node2ID(here);
3887 	}
3888 }
3889