xref: /freebsd/sys/netgraph/ng_base.c (revision dd41de95a84d979615a2ef11df6850622bf6184e)
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 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 	/* Check the name is valid */
859 	for (i = 0; i < NG_NODESIZ; i++) {
860 		if (name[i] == '\0' || name[i] == '.' || name[i] == ':')
861 			break;
862 	}
863 	if (i == 0 || name[i] != '\0') {
864 		TRAP_ERROR();
865 		return (EINVAL);
866 	}
867 	if (ng_decodeidname(name) != 0) { /* valid IDs not allowed here */
868 		TRAP_ERROR();
869 		return (EINVAL);
870 	}
871 
872 	NAMEHASH_WLOCK();
873 	if (V_ng_named_nodes * 2 > V_ng_name_hmask)
874 		ng_name_rehash();
875 
876 	hash = hash32_str(name, HASHINIT) & V_ng_name_hmask;
877 	/* Check the name isn't already being used. */
878 	LIST_FOREACH(node2, &V_ng_name_hash[hash], nd_nodes)
879 		if (NG_NODE_IS_VALID(node2) &&
880 		    (strcmp(NG_NODE_NAME(node2), name) == 0)) {
881 			NAMEHASH_WUNLOCK();
882 			return (EADDRINUSE);
883 		}
884 
885 	if (NG_NODE_HAS_NAME(node))
886 		LIST_REMOVE(node, nd_nodes);
887 	else
888 		V_ng_named_nodes++;
889 	/* Copy it. */
890 	strlcpy(NG_NODE_NAME(node), name, NG_NODESIZ);
891 	/* Update name hash. */
892 	LIST_INSERT_HEAD(&V_ng_name_hash[hash], node, nd_nodes);
893 	NAMEHASH_WUNLOCK();
894 
895 	return (0);
896 }
897 
898 /*
899  * Find a node by absolute name. The name should NOT end with ':'
900  * The name "." means "this node" and "[xxx]" means "the node
901  * with ID (ie, at address) xxx".
902  *
903  * Returns the node if found, else NULL.
904  * Eventually should add something faster than a sequential search.
905  * Note it acquires a reference on the node so you can be sure it's still
906  * there.
907  */
908 node_p
909 ng_name2noderef(node_p here, const char *name)
910 {
911 	node_p node;
912 	ng_ID_t temp;
913 	int	hash;
914 
915 	/* "." means "this node" */
916 	if (strcmp(name, ".") == 0) {
917 		NG_NODE_REF(here);
918 		return(here);
919 	}
920 
921 	/* Check for name-by-ID */
922 	if ((temp = ng_decodeidname(name)) != 0) {
923 		return (ng_ID2noderef(temp));
924 	}
925 
926 	/* Find node by name. */
927 	hash = hash32_str(name, HASHINIT) & V_ng_name_hmask;
928 	NAMEHASH_RLOCK();
929 	LIST_FOREACH(node, &V_ng_name_hash[hash], nd_nodes)
930 		if (NG_NODE_IS_VALID(node) &&
931 		    (strcmp(NG_NODE_NAME(node), name) == 0)) {
932 			NG_NODE_REF(node);
933 			break;
934 		}
935 	NAMEHASH_RUNLOCK();
936 
937 	return (node);
938 }
939 
940 /*
941  * Decode an ID name, eg. "[f03034de]". Returns 0 if the
942  * string is not valid, otherwise returns the value.
943  */
944 static ng_ID_t
945 ng_decodeidname(const char *name)
946 {
947 	const int len = strlen(name);
948 	char *eptr;
949 	u_long val;
950 
951 	/* Check for proper length, brackets, no leading junk */
952 	if ((len < 3) || (name[0] != '[') || (name[len - 1] != ']') ||
953 	    (!isxdigit(name[1])))
954 		return ((ng_ID_t)0);
955 
956 	/* Decode number */
957 	val = strtoul(name + 1, &eptr, 16);
958 	if ((eptr - name != len - 1) || (val == ULONG_MAX) || (val == 0))
959 		return ((ng_ID_t)0);
960 
961 	return ((ng_ID_t)val);
962 }
963 
964 /*
965  * Remove a name from a node. This should only be called
966  * when shutting down and removing the node.
967  */
968 void
969 ng_unname(node_p node)
970 {
971 }
972 
973 /*
974  * Allocate a bigger name hash.
975  */
976 static void
977 ng_name_rehash()
978 {
979 	struct nodehash *new;
980 	uint32_t hash;
981 	u_long hmask;
982 	node_p node, node2;
983 	int i;
984 
985 	new = hashinit_flags((V_ng_name_hmask + 1) * 2, M_NETGRAPH_NODE, &hmask,
986 	    HASH_NOWAIT);
987 	if (new == NULL)
988 		return;
989 
990 	for (i = 0; i <= V_ng_name_hmask; i++)
991 		LIST_FOREACH_SAFE(node, &V_ng_name_hash[i], nd_nodes, node2) {
992 #ifdef INVARIANTS
993 			LIST_REMOVE(node, nd_nodes);
994 #endif
995 			hash = hash32_str(NG_NODE_NAME(node), HASHINIT) & hmask;
996 			LIST_INSERT_HEAD(&new[hash], node, nd_nodes);
997 		}
998 
999 	hashdestroy(V_ng_name_hash, M_NETGRAPH_NODE, V_ng_name_hmask);
1000 	V_ng_name_hash = new;
1001 	V_ng_name_hmask = hmask;
1002 }
1003 
1004 /*
1005  * Allocate a bigger ID hash.
1006  */
1007 static void
1008 ng_ID_rehash()
1009 {
1010 	struct nodehash *new;
1011 	uint32_t hash;
1012 	u_long hmask;
1013 	node_p node, node2;
1014 	int i;
1015 
1016 	new = hashinit_flags((V_ng_ID_hmask + 1) * 2, M_NETGRAPH_NODE, &hmask,
1017 	    HASH_NOWAIT);
1018 	if (new == NULL)
1019 		return;
1020 
1021 	for (i = 0; i <= V_ng_ID_hmask; i++)
1022 		LIST_FOREACH_SAFE(node, &V_ng_ID_hash[i], nd_idnodes, node2) {
1023 #ifdef INVARIANTS
1024 			LIST_REMOVE(node, nd_idnodes);
1025 #endif
1026 			hash = (node->nd_ID % (hmask + 1));
1027 			LIST_INSERT_HEAD(&new[hash], node, nd_idnodes);
1028 		}
1029 
1030 	hashdestroy(V_ng_ID_hash, M_NETGRAPH_NODE, V_ng_name_hmask);
1031 	V_ng_ID_hash = new;
1032 	V_ng_ID_hmask = hmask;
1033 }
1034 
1035 /************************************************************************
1036 			Hook routines
1037  Names are not optional. Hooks are always connected, except for a
1038  brief moment within these routines. On invalidation or during creation
1039  they are connected to the 'dead' hook.
1040 ************************************************************************/
1041 
1042 /*
1043  * Remove a hook reference
1044  */
1045 void
1046 ng_unref_hook(hook_p hook)
1047 {
1048 
1049 	if (hook == &ng_deadhook)
1050 		return;
1051 
1052 	if (refcount_release(&hook->hk_refs)) { /* we were the last */
1053 		if (_NG_HOOK_NODE(hook)) /* it'll probably be ng_deadnode */
1054 			_NG_NODE_UNREF((_NG_HOOK_NODE(hook)));
1055 		NG_FREE_HOOK(hook);
1056 	}
1057 }
1058 
1059 /*
1060  * Add an unconnected hook to a node. Only used internally.
1061  * Assumes node is locked. (XXX not yet true )
1062  */
1063 static int
1064 ng_add_hook(node_p node, const char *name, hook_p *hookp)
1065 {
1066 	hook_p hook;
1067 	int error = 0;
1068 
1069 	/* Check that the given name is good */
1070 	if (name == NULL) {
1071 		TRAP_ERROR();
1072 		return (EINVAL);
1073 	}
1074 	if (ng_findhook(node, name) != NULL) {
1075 		TRAP_ERROR();
1076 		return (EEXIST);
1077 	}
1078 
1079 	/* Allocate the hook and link it up */
1080 	NG_ALLOC_HOOK(hook);
1081 	if (hook == NULL) {
1082 		TRAP_ERROR();
1083 		return (ENOMEM);
1084 	}
1085 	hook->hk_refs = 1;		/* add a reference for us to return */
1086 	hook->hk_flags = HK_INVALID;
1087 	hook->hk_peer = &ng_deadhook;	/* start off this way */
1088 	hook->hk_node = node;
1089 	NG_NODE_REF(node);		/* each hook counts as a reference */
1090 
1091 	/* Set hook name */
1092 	strlcpy(NG_HOOK_NAME(hook), name, NG_HOOKSIZ);
1093 
1094 	/*
1095 	 * Check if the node type code has something to say about it
1096 	 * If it fails, the unref of the hook will also unref the node.
1097 	 */
1098 	if (node->nd_type->newhook != NULL) {
1099 		if ((error = (*node->nd_type->newhook)(node, hook, name))) {
1100 			NG_HOOK_UNREF(hook);	/* this frees the hook */
1101 			return (error);
1102 		}
1103 	}
1104 	/*
1105 	 * The 'type' agrees so far, so go ahead and link it in.
1106 	 * We'll ask again later when we actually connect the hooks.
1107 	 */
1108 	LIST_INSERT_HEAD(&node->nd_hooks, hook, hk_hooks);
1109 	node->nd_numhooks++;
1110 	NG_HOOK_REF(hook);	/* one for the node */
1111 
1112 	if (hookp)
1113 		*hookp = hook;
1114 	return (0);
1115 }
1116 
1117 /*
1118  * Find a hook
1119  *
1120  * Node types may supply their own optimized routines for finding
1121  * hooks.  If none is supplied, we just do a linear search.
1122  * XXX Possibly we should add a reference to the hook?
1123  */
1124 hook_p
1125 ng_findhook(node_p node, const char *name)
1126 {
1127 	hook_p hook;
1128 
1129 	if (node->nd_type->findhook != NULL)
1130 		return (*node->nd_type->findhook)(node, name);
1131 	LIST_FOREACH(hook, &node->nd_hooks, hk_hooks) {
1132 		if (NG_HOOK_IS_VALID(hook) &&
1133 		    (strcmp(NG_HOOK_NAME(hook), name) == 0))
1134 			return (hook);
1135 	}
1136 	return (NULL);
1137 }
1138 
1139 /*
1140  * Destroy a hook
1141  *
1142  * As hooks are always attached, this really destroys two hooks.
1143  * The one given, and the one attached to it. Disconnect the hooks
1144  * from each other first. We reconnect the peer hook to the 'dead'
1145  * hook so that it can still exist after we depart. We then
1146  * send the peer its own destroy message. This ensures that we only
1147  * interact with the peer's structures when it is locked processing that
1148  * message. We hold a reference to the peer hook so we are guaranteed that
1149  * the peer hook and node are still going to exist until
1150  * we are finished there as the hook holds a ref on the node.
1151  * We run this same code again on the peer hook, but that time it is already
1152  * attached to the 'dead' hook.
1153  *
1154  * This routine is called at all stages of hook creation
1155  * on error detection and must be able to handle any such stage.
1156  */
1157 void
1158 ng_destroy_hook(hook_p hook)
1159 {
1160 	hook_p peer;
1161 	node_p node;
1162 
1163 	if (hook == &ng_deadhook) {	/* better safe than sorry */
1164 		printf("ng_destroy_hook called on deadhook\n");
1165 		return;
1166 	}
1167 
1168 	/*
1169 	 * Protect divorce process with mutex, to avoid races on
1170 	 * simultaneous disconnect.
1171 	 */
1172 	TOPOLOGY_WLOCK();
1173 
1174 	hook->hk_flags |= HK_INVALID;
1175 
1176 	peer = NG_HOOK_PEER(hook);
1177 	node = NG_HOOK_NODE(hook);
1178 
1179 	if (peer && (peer != &ng_deadhook)) {
1180 		/*
1181 		 * Set the peer to point to ng_deadhook
1182 		 * from this moment on we are effectively independent it.
1183 		 * send it an rmhook message of its own.
1184 		 */
1185 		peer->hk_peer = &ng_deadhook;	/* They no longer know us */
1186 		hook->hk_peer = &ng_deadhook;	/* Nor us, them */
1187 		if (NG_HOOK_NODE(peer) == &ng_deadnode) {
1188 			/*
1189 			 * If it's already divorced from a node,
1190 			 * just free it.
1191 			 */
1192 			TOPOLOGY_WUNLOCK();
1193 		} else {
1194 			TOPOLOGY_WUNLOCK();
1195 			ng_rmhook_self(peer); 	/* Send it a surprise */
1196 		}
1197 		NG_HOOK_UNREF(peer);		/* account for peer link */
1198 		NG_HOOK_UNREF(hook);		/* account for peer link */
1199 	} else
1200 		TOPOLOGY_WUNLOCK();
1201 
1202 	TOPOLOGY_NOTOWNED();
1203 
1204 	/*
1205 	 * Remove the hook from the node's list to avoid possible recursion
1206 	 * in case the disconnection results in node shutdown.
1207 	 */
1208 	if (node == &ng_deadnode) { /* happens if called from ng_con_nodes() */
1209 		return;
1210 	}
1211 	LIST_REMOVE(hook, hk_hooks);
1212 	node->nd_numhooks--;
1213 	if (node->nd_type->disconnect) {
1214 		/*
1215 		 * The type handler may elect to destroy the node so don't
1216 		 * trust its existence after this point. (except
1217 		 * that we still hold a reference on it. (which we
1218 		 * inherrited from the hook we are destroying)
1219 		 */
1220 		(*node->nd_type->disconnect) (hook);
1221 	}
1222 
1223 	/*
1224 	 * Note that because we will point to ng_deadnode, the original node
1225 	 * is not decremented automatically so we do that manually.
1226 	 */
1227 	_NG_HOOK_NODE(hook) = &ng_deadnode;
1228 	NG_NODE_UNREF(node);	/* We no longer point to it so adjust count */
1229 	NG_HOOK_UNREF(hook);	/* Account for linkage (in list) to node */
1230 }
1231 
1232 /*
1233  * Take two hooks on a node and merge the connection so that the given node
1234  * is effectively bypassed.
1235  */
1236 int
1237 ng_bypass(hook_p hook1, hook_p hook2)
1238 {
1239 	if (hook1->hk_node != hook2->hk_node) {
1240 		TRAP_ERROR();
1241 		return (EINVAL);
1242 	}
1243 	TOPOLOGY_WLOCK();
1244 	if (NG_HOOK_NOT_VALID(hook1) || NG_HOOK_NOT_VALID(hook2)) {
1245 		TOPOLOGY_WUNLOCK();
1246 		return (EINVAL);
1247 	}
1248 	hook1->hk_peer->hk_peer = hook2->hk_peer;
1249 	hook2->hk_peer->hk_peer = hook1->hk_peer;
1250 
1251 	hook1->hk_peer = &ng_deadhook;
1252 	hook2->hk_peer = &ng_deadhook;
1253 	TOPOLOGY_WUNLOCK();
1254 
1255 	NG_HOOK_UNREF(hook1);
1256 	NG_HOOK_UNREF(hook2);
1257 
1258 	/* XXX If we ever cache methods on hooks update them as well */
1259 	ng_destroy_hook(hook1);
1260 	ng_destroy_hook(hook2);
1261 	return (0);
1262 }
1263 
1264 /*
1265  * Install a new netgraph type
1266  */
1267 int
1268 ng_newtype(struct ng_type *tp)
1269 {
1270 	const size_t namelen = strlen(tp->name);
1271 
1272 	/* Check version and type name fields */
1273 	if ((tp->version != NG_ABI_VERSION) || (namelen == 0) ||
1274 	    (namelen >= NG_TYPESIZ)) {
1275 		TRAP_ERROR();
1276 		if (tp->version != NG_ABI_VERSION) {
1277 			printf("Netgraph: Node type rejected. ABI mismatch. "
1278 			    "Suggest recompile\n");
1279 		}
1280 		return (EINVAL);
1281 	}
1282 
1283 	/* Check for name collision */
1284 	if (ng_findtype(tp->name) != NULL) {
1285 		TRAP_ERROR();
1286 		return (EEXIST);
1287 	}
1288 
1289 	/* Link in new type */
1290 	TYPELIST_WLOCK();
1291 	LIST_INSERT_HEAD(&ng_typelist, tp, types);
1292 	tp->refs = 1;	/* first ref is linked list */
1293 	TYPELIST_WUNLOCK();
1294 	return (0);
1295 }
1296 
1297 /*
1298  * unlink a netgraph type
1299  * If no examples exist
1300  */
1301 int
1302 ng_rmtype(struct ng_type *tp)
1303 {
1304 	/* Check for name collision */
1305 	if (tp->refs != 1) {
1306 		TRAP_ERROR();
1307 		return (EBUSY);
1308 	}
1309 
1310 	/* Unlink type */
1311 	TYPELIST_WLOCK();
1312 	LIST_REMOVE(tp, types);
1313 	TYPELIST_WUNLOCK();
1314 	return (0);
1315 }
1316 
1317 /*
1318  * Look for a type of the name given
1319  */
1320 struct ng_type *
1321 ng_findtype(const char *typename)
1322 {
1323 	struct ng_type *type;
1324 
1325 	TYPELIST_RLOCK();
1326 	LIST_FOREACH(type, &ng_typelist, types) {
1327 		if (strcmp(type->name, typename) == 0)
1328 			break;
1329 	}
1330 	TYPELIST_RUNLOCK();
1331 	return (type);
1332 }
1333 
1334 /************************************************************************
1335 			Composite routines
1336 ************************************************************************/
1337 /*
1338  * Connect two nodes using the specified hooks, using queued functions.
1339  */
1340 static int
1341 ng_con_part3(node_p node, item_p item, hook_p hook)
1342 {
1343 	int	error = 0;
1344 
1345 	/*
1346 	 * When we run, we know that the node 'node' is locked for us.
1347 	 * Our caller has a reference on the hook.
1348 	 * Our caller has a reference on the node.
1349 	 * (In this case our caller is ng_apply_item() ).
1350 	 * The peer hook has a reference on the hook.
1351 	 * We are all set up except for the final call to the node, and
1352 	 * the clearing of the INVALID flag.
1353 	 */
1354 	if (NG_HOOK_NODE(hook) == &ng_deadnode) {
1355 		/*
1356 		 * The node must have been freed again since we last visited
1357 		 * here. ng_destry_hook() has this effect but nothing else does.
1358 		 * We should just release our references and
1359 		 * free anything we can think of.
1360 		 * Since we know it's been destroyed, and it's our caller
1361 		 * that holds the references, just return.
1362 		 */
1363 		ERROUT(ENOENT);
1364 	}
1365 	if (hook->hk_node->nd_type->connect) {
1366 		if ((error = (*hook->hk_node->nd_type->connect) (hook))) {
1367 			ng_destroy_hook(hook);	/* also zaps peer */
1368 			printf("failed in ng_con_part3()\n");
1369 			ERROUT(error);
1370 		}
1371 	}
1372 	/*
1373 	 *  XXX this is wrong for SMP. Possibly we need
1374 	 * to separate out 'create' and 'invalid' flags.
1375 	 * should only set flags on hooks we have locked under our node.
1376 	 */
1377 	hook->hk_flags &= ~HK_INVALID;
1378 done:
1379 	NG_FREE_ITEM(item);
1380 	return (error);
1381 }
1382 
1383 static int
1384 ng_con_part2(node_p node, item_p item, hook_p hook)
1385 {
1386 	hook_p	peer;
1387 	int	error = 0;
1388 
1389 	/*
1390 	 * When we run, we know that the node 'node' is locked for us.
1391 	 * Our caller has a reference on the hook.
1392 	 * Our caller has a reference on the node.
1393 	 * (In this case our caller is ng_apply_item() ).
1394 	 * The peer hook has a reference on the hook.
1395 	 * our node pointer points to the 'dead' node.
1396 	 * First check the hook name is unique.
1397 	 * Should not happen because we checked before queueing this.
1398 	 */
1399 	if (ng_findhook(node, NG_HOOK_NAME(hook)) != NULL) {
1400 		TRAP_ERROR();
1401 		ng_destroy_hook(hook); /* should destroy peer too */
1402 		printf("failed in ng_con_part2()\n");
1403 		ERROUT(EEXIST);
1404 	}
1405 	/*
1406 	 * Check if the node type code has something to say about it
1407 	 * If it fails, the unref of the hook will also unref the attached node,
1408 	 * however since that node is 'ng_deadnode' this will do nothing.
1409 	 * The peer hook will also be destroyed.
1410 	 */
1411 	if (node->nd_type->newhook != NULL) {
1412 		if ((error = (*node->nd_type->newhook)(node, hook,
1413 		    hook->hk_name))) {
1414 			ng_destroy_hook(hook); /* should destroy peer too */
1415 			printf("failed in ng_con_part2()\n");
1416 			ERROUT(error);
1417 		}
1418 	}
1419 
1420 	/*
1421 	 * The 'type' agrees so far, so go ahead and link it in.
1422 	 * We'll ask again later when we actually connect the hooks.
1423 	 */
1424 	hook->hk_node = node;		/* just overwrite ng_deadnode */
1425 	NG_NODE_REF(node);		/* each hook counts as a reference */
1426 	LIST_INSERT_HEAD(&node->nd_hooks, hook, hk_hooks);
1427 	node->nd_numhooks++;
1428 	NG_HOOK_REF(hook);	/* one for the node */
1429 
1430 	/*
1431 	 * We now have a symmetrical situation, where both hooks have been
1432 	 * linked to their nodes, the newhook methods have been called
1433 	 * And the references are all correct. The hooks are still marked
1434 	 * as invalid, as we have not called the 'connect' methods
1435 	 * yet.
1436 	 * We can call the local one immediately as we have the
1437 	 * node locked, but we need to queue the remote one.
1438 	 */
1439 	if (hook->hk_node->nd_type->connect) {
1440 		if ((error = (*hook->hk_node->nd_type->connect) (hook))) {
1441 			ng_destroy_hook(hook);	/* also zaps peer */
1442 			printf("failed in ng_con_part2(A)\n");
1443 			ERROUT(error);
1444 		}
1445 	}
1446 
1447 	/*
1448 	 * Acquire topo mutex to avoid race with ng_destroy_hook().
1449 	 */
1450 	TOPOLOGY_RLOCK();
1451 	peer = hook->hk_peer;
1452 	if (peer == &ng_deadhook) {
1453 		TOPOLOGY_RUNLOCK();
1454 		printf("failed in ng_con_part2(B)\n");
1455 		ng_destroy_hook(hook);
1456 		ERROUT(ENOENT);
1457 	}
1458 	TOPOLOGY_RUNLOCK();
1459 
1460 	if ((error = ng_send_fn2(peer->hk_node, peer, item, &ng_con_part3,
1461 	    NULL, 0, NG_REUSE_ITEM))) {
1462 		printf("failed in ng_con_part2(C)\n");
1463 		ng_destroy_hook(hook);	/* also zaps peer */
1464 		return (error);		/* item was consumed. */
1465 	}
1466 	hook->hk_flags &= ~HK_INVALID; /* need both to be able to work */
1467 	return (0);			/* item was consumed. */
1468 done:
1469 	NG_FREE_ITEM(item);
1470 	return (error);
1471 }
1472 
1473 /*
1474  * Connect this node with another node. We assume that this node is
1475  * currently locked, as we are only called from an NGM_CONNECT message.
1476  */
1477 static int
1478 ng_con_nodes(item_p item, node_p node, const char *name,
1479     node_p node2, const char *name2)
1480 {
1481 	int	error;
1482 	hook_p	hook;
1483 	hook_p	hook2;
1484 
1485 	if (ng_findhook(node2, name2) != NULL) {
1486 		return(EEXIST);
1487 	}
1488 	if ((error = ng_add_hook(node, name, &hook)))  /* gives us a ref */
1489 		return (error);
1490 	/* Allocate the other hook and link it up */
1491 	NG_ALLOC_HOOK(hook2);
1492 	if (hook2 == NULL) {
1493 		TRAP_ERROR();
1494 		ng_destroy_hook(hook);	/* XXX check ref counts so far */
1495 		NG_HOOK_UNREF(hook);	/* including our ref */
1496 		return (ENOMEM);
1497 	}
1498 	hook2->hk_refs = 1;		/* start with a reference for us. */
1499 	hook2->hk_flags = HK_INVALID;
1500 	hook2->hk_peer = hook;		/* Link the two together */
1501 	hook->hk_peer = hook2;
1502 	NG_HOOK_REF(hook);		/* Add a ref for the peer to each*/
1503 	NG_HOOK_REF(hook2);
1504 	hook2->hk_node = &ng_deadnode;
1505 	strlcpy(NG_HOOK_NAME(hook2), name2, NG_HOOKSIZ);
1506 
1507 	/*
1508 	 * Queue the function above.
1509 	 * Procesing continues in that function in the lock context of
1510 	 * the other node.
1511 	 */
1512 	if ((error = ng_send_fn2(node2, hook2, item, &ng_con_part2, NULL, 0,
1513 	    NG_NOFLAGS))) {
1514 		printf("failed in ng_con_nodes(): %d\n", error);
1515 		ng_destroy_hook(hook);	/* also zaps peer */
1516 	}
1517 
1518 	NG_HOOK_UNREF(hook);		/* Let each hook go if it wants to */
1519 	NG_HOOK_UNREF(hook2);
1520 	return (error);
1521 }
1522 
1523 /*
1524  * Make a peer and connect.
1525  * We assume that the local node is locked.
1526  * The new node probably doesn't need a lock until
1527  * it has a hook, because it cannot really have any work until then,
1528  * but we should think about it a bit more.
1529  *
1530  * The problem may come if the other node also fires up
1531  * some hardware or a timer or some other source of activation,
1532  * also it may already get a command msg via it's ID.
1533  *
1534  * We could use the same method as ng_con_nodes() but we'd have
1535  * to add ability to remove the node when failing. (Not hard, just
1536  * make arg1 point to the node to remove).
1537  * Unless of course we just ignore failure to connect and leave
1538  * an unconnected node?
1539  */
1540 static int
1541 ng_mkpeer(node_p node, const char *name, const char *name2, char *type)
1542 {
1543 	node_p	node2;
1544 	hook_p	hook1, hook2;
1545 	int	error;
1546 
1547 	if ((error = ng_make_node(type, &node2))) {
1548 		return (error);
1549 	}
1550 
1551 	if ((error = ng_add_hook(node, name, &hook1))) { /* gives us a ref */
1552 		ng_rmnode(node2, NULL, NULL, 0);
1553 		return (error);
1554 	}
1555 
1556 	if ((error = ng_add_hook(node2, name2, &hook2))) {
1557 		ng_rmnode(node2, NULL, NULL, 0);
1558 		ng_destroy_hook(hook1);
1559 		NG_HOOK_UNREF(hook1);
1560 		return (error);
1561 	}
1562 
1563 	/*
1564 	 * Actually link the two hooks together.
1565 	 */
1566 	hook1->hk_peer = hook2;
1567 	hook2->hk_peer = hook1;
1568 
1569 	/* Each hook is referenced by the other */
1570 	NG_HOOK_REF(hook1);
1571 	NG_HOOK_REF(hook2);
1572 
1573 	/* Give each node the opportunity to veto the pending connection */
1574 	if (hook1->hk_node->nd_type->connect) {
1575 		error = (*hook1->hk_node->nd_type->connect) (hook1);
1576 	}
1577 
1578 	if ((error == 0) && hook2->hk_node->nd_type->connect) {
1579 		error = (*hook2->hk_node->nd_type->connect) (hook2);
1580 	}
1581 
1582 	/*
1583 	 * drop the references we were holding on the two hooks.
1584 	 */
1585 	if (error) {
1586 		ng_destroy_hook(hook2);	/* also zaps hook1 */
1587 		ng_rmnode(node2, NULL, NULL, 0);
1588 	} else {
1589 		/* As a last act, allow the hooks to be used */
1590 		hook1->hk_flags &= ~HK_INVALID;
1591 		hook2->hk_flags &= ~HK_INVALID;
1592 	}
1593 	NG_HOOK_UNREF(hook1);
1594 	NG_HOOK_UNREF(hook2);
1595 	return (error);
1596 }
1597 
1598 /************************************************************************
1599 		Utility routines to send self messages
1600 ************************************************************************/
1601 
1602 /* Shut this node down as soon as everyone is clear of it */
1603 /* Should add arg "immediately" to jump the queue */
1604 int
1605 ng_rmnode_self(node_p node)
1606 {
1607 	int		error;
1608 
1609 	if (node == &ng_deadnode)
1610 		return (0);
1611 	node->nd_flags |= NGF_INVALID;
1612 	if (node->nd_flags & NGF_CLOSING)
1613 		return (0);
1614 
1615 	error = ng_send_fn(node, NULL, &ng_rmnode, NULL, 0);
1616 	return (error);
1617 }
1618 
1619 static void
1620 ng_rmhook_part2(node_p node, hook_p hook, void *arg1, int arg2)
1621 {
1622 	ng_destroy_hook(hook);
1623 	return ;
1624 }
1625 
1626 int
1627 ng_rmhook_self(hook_p hook)
1628 {
1629 	int		error;
1630 	node_p node = NG_HOOK_NODE(hook);
1631 
1632 	if (node == &ng_deadnode)
1633 		return (0);
1634 
1635 	error = ng_send_fn(node, hook, &ng_rmhook_part2, NULL, 0);
1636 	return (error);
1637 }
1638 
1639 /***********************************************************************
1640  * Parse and verify a string of the form:  <NODE:><PATH>
1641  *
1642  * Such a string can refer to a specific node or a specific hook
1643  * on a specific node, depending on how you look at it. In the
1644  * latter case, the PATH component must not end in a dot.
1645  *
1646  * Both <NODE:> and <PATH> are optional. The <PATH> is a string
1647  * of hook names separated by dots. This breaks out the original
1648  * string, setting *nodep to "NODE" (or NULL if none) and *pathp
1649  * to "PATH" (or NULL if degenerate). Also, *hookp will point to
1650  * the final hook component of <PATH>, if any, otherwise NULL.
1651  *
1652  * This returns -1 if the path is malformed. The char ** are optional.
1653  ***********************************************************************/
1654 int
1655 ng_path_parse(char *addr, char **nodep, char **pathp, char **hookp)
1656 {
1657 	char	*node, *path, *hook;
1658 	int	k;
1659 
1660 	/*
1661 	 * Extract absolute NODE, if any
1662 	 */
1663 	for (path = addr; *path && *path != ':'; path++);
1664 	if (*path) {
1665 		node = addr;	/* Here's the NODE */
1666 		*path++ = '\0';	/* Here's the PATH */
1667 
1668 		/* Node name must not be empty */
1669 		if (!*node)
1670 			return -1;
1671 
1672 		/* A name of "." is OK; otherwise '.' not allowed */
1673 		if (strcmp(node, ".") != 0) {
1674 			for (k = 0; node[k]; k++)
1675 				if (node[k] == '.')
1676 					return -1;
1677 		}
1678 	} else {
1679 		node = NULL;	/* No absolute NODE */
1680 		path = addr;	/* Here's the PATH */
1681 	}
1682 
1683 	/* Snoop for illegal characters in PATH */
1684 	for (k = 0; path[k]; k++)
1685 		if (path[k] == ':')
1686 			return -1;
1687 
1688 	/* Check for no repeated dots in PATH */
1689 	for (k = 0; path[k]; k++)
1690 		if (path[k] == '.' && path[k + 1] == '.')
1691 			return -1;
1692 
1693 	/* Remove extra (degenerate) dots from beginning or end of PATH */
1694 	if (path[0] == '.')
1695 		path++;
1696 	if (*path && path[strlen(path) - 1] == '.')
1697 		path[strlen(path) - 1] = 0;
1698 
1699 	/* If PATH has a dot, then we're not talking about a hook */
1700 	if (*path) {
1701 		for (hook = path, k = 0; path[k]; k++)
1702 			if (path[k] == '.') {
1703 				hook = NULL;
1704 				break;
1705 			}
1706 	} else
1707 		path = hook = NULL;
1708 
1709 	/* Done */
1710 	if (nodep)
1711 		*nodep = node;
1712 	if (pathp)
1713 		*pathp = path;
1714 	if (hookp)
1715 		*hookp = hook;
1716 	return (0);
1717 }
1718 
1719 /*
1720  * Given a path, which may be absolute or relative, and a starting node,
1721  * return the destination node.
1722  */
1723 int
1724 ng_path2noderef(node_p here, const char *address, node_p *destp,
1725     hook_p *lasthook)
1726 {
1727 	char    fullpath[NG_PATHSIZ];
1728 	char   *nodename, *path;
1729 	node_p  node, oldnode;
1730 
1731 	/* Initialize */
1732 	if (destp == NULL) {
1733 		TRAP_ERROR();
1734 		return EINVAL;
1735 	}
1736 	*destp = NULL;
1737 
1738 	/* Make a writable copy of address for ng_path_parse() */
1739 	strncpy(fullpath, address, sizeof(fullpath) - 1);
1740 	fullpath[sizeof(fullpath) - 1] = '\0';
1741 
1742 	/* Parse out node and sequence of hooks */
1743 	if (ng_path_parse(fullpath, &nodename, &path, NULL) < 0) {
1744 		TRAP_ERROR();
1745 		return EINVAL;
1746 	}
1747 
1748 	/*
1749 	 * For an absolute address, jump to the starting node.
1750 	 * Note that this holds a reference on the node for us.
1751 	 * Don't forget to drop the reference if we don't need it.
1752 	 */
1753 	if (nodename) {
1754 		node = ng_name2noderef(here, nodename);
1755 		if (node == NULL) {
1756 			TRAP_ERROR();
1757 			return (ENOENT);
1758 		}
1759 	} else {
1760 		if (here == NULL) {
1761 			TRAP_ERROR();
1762 			return (EINVAL);
1763 		}
1764 		node = here;
1765 		NG_NODE_REF(node);
1766 	}
1767 
1768 	if (path == NULL) {
1769 		if (lasthook != NULL)
1770 			*lasthook = NULL;
1771 		*destp = node;
1772 		return (0);
1773 	}
1774 
1775 	/*
1776 	 * Now follow the sequence of hooks
1777 	 *
1778 	 * XXXGL: The path may demolish as we go the sequence, but if
1779 	 * we hold the topology mutex at critical places, then, I hope,
1780 	 * we would always have valid pointers in hand, although the
1781 	 * path behind us may no longer exist.
1782 	 */
1783 	for (;;) {
1784 		hook_p hook;
1785 		char *segment;
1786 
1787 		/*
1788 		 * Break out the next path segment. Replace the dot we just
1789 		 * found with a NUL; "path" points to the next segment (or the
1790 		 * NUL at the end).
1791 		 */
1792 		for (segment = path; *path != '\0'; path++) {
1793 			if (*path == '.') {
1794 				*path++ = '\0';
1795 				break;
1796 			}
1797 		}
1798 
1799 		/* We have a segment, so look for a hook by that name */
1800 		hook = ng_findhook(node, segment);
1801 
1802 		TOPOLOGY_WLOCK();
1803 		/* Can't get there from here... */
1804 		if (hook == NULL || NG_HOOK_PEER(hook) == NULL ||
1805 		    NG_HOOK_NOT_VALID(hook) ||
1806 		    NG_HOOK_NOT_VALID(NG_HOOK_PEER(hook))) {
1807 			TRAP_ERROR();
1808 			NG_NODE_UNREF(node);
1809 			TOPOLOGY_WUNLOCK();
1810 			return (ENOENT);
1811 		}
1812 
1813 		/*
1814 		 * Hop on over to the next node
1815 		 * XXX
1816 		 * Big race conditions here as hooks and nodes go away
1817 		 * *** Idea.. store an ng_ID_t in each hook and use that
1818 		 * instead of the direct hook in this crawl?
1819 		 */
1820 		oldnode = node;
1821 		if ((node = NG_PEER_NODE(hook)))
1822 			NG_NODE_REF(node);	/* XXX RACE */
1823 		NG_NODE_UNREF(oldnode);	/* XXX another race */
1824 		if (NG_NODE_NOT_VALID(node)) {
1825 			NG_NODE_UNREF(node);	/* XXX more races */
1826 			TOPOLOGY_WUNLOCK();
1827 			TRAP_ERROR();
1828 			return (ENXIO);
1829 		}
1830 
1831 		if (*path == '\0') {
1832 			if (lasthook != NULL) {
1833 				if (hook != NULL) {
1834 					*lasthook = NG_HOOK_PEER(hook);
1835 					NG_HOOK_REF(*lasthook);
1836 				} else
1837 					*lasthook = NULL;
1838 			}
1839 			TOPOLOGY_WUNLOCK();
1840 			*destp = node;
1841 			return (0);
1842 		}
1843 		TOPOLOGY_WUNLOCK();
1844 	}
1845 }
1846 
1847 /***************************************************************\
1848 * Input queue handling.
1849 * All activities are submitted to the node via the input queue
1850 * which implements a multiple-reader/single-writer gate.
1851 * Items which cannot be handled immediately are queued.
1852 *
1853 * read-write queue locking inline functions			*
1854 \***************************************************************/
1855 
1856 static __inline void	ng_queue_rw(node_p node, item_p  item, int rw);
1857 static __inline item_p	ng_dequeue(node_p node, int *rw);
1858 static __inline item_p	ng_acquire_read(node_p node, item_p  item);
1859 static __inline item_p	ng_acquire_write(node_p node, item_p  item);
1860 static __inline void	ng_leave_read(node_p node);
1861 static __inline void	ng_leave_write(node_p node);
1862 
1863 /*
1864  * Definition of the bits fields in the ng_queue flag word.
1865  * Defined here rather than in netgraph.h because no-one should fiddle
1866  * with them.
1867  *
1868  * The ordering here may be important! don't shuffle these.
1869  */
1870 /*-
1871  Safety Barrier--------+ (adjustable to suit taste) (not used yet)
1872                        |
1873                        V
1874 +-------+-------+-------+-------+-------+-------+-------+-------+
1875   | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
1876   | |A|c|t|i|v|e| |R|e|a|d|e|r| |C|o|u|n|t| | | | | | | | | |P|A|
1877   | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |O|W|
1878 +-------+-------+-------+-------+-------+-------+-------+-------+
1879   \___________________________ ____________________________/ | |
1880                             V                                | |
1881                   [active reader count]                      | |
1882                                                              | |
1883             Operation Pending -------------------------------+ |
1884                                                                |
1885           Active Writer ---------------------------------------+
1886 
1887 Node queue has such semantics:
1888 - All flags modifications are atomic.
1889 - Reader count can be incremented only if there is no writer or pending flags.
1890   As soon as this can't be done with single operation, it is implemented with
1891   spin loop and atomic_cmpset().
1892 - Writer flag can be set only if there is no any bits set.
1893   It is implemented with atomic_cmpset().
1894 - Pending flag can be set any time, but to avoid collision on queue processing
1895   all queue fields are protected by the mutex.
1896 - Queue processing thread reads queue holding the mutex, but releases it while
1897   processing. When queue is empty pending flag is removed.
1898 */
1899 
1900 #define WRITER_ACTIVE	0x00000001
1901 #define OP_PENDING	0x00000002
1902 #define READER_INCREMENT 0x00000004
1903 #define READER_MASK	0xfffffffc	/* Not valid if WRITER_ACTIVE is set */
1904 #define SAFETY_BARRIER	0x00100000	/* 128K items queued should be enough */
1905 
1906 /* Defines of more elaborate states on the queue */
1907 /* Mask of bits a new read cares about */
1908 #define NGQ_RMASK	(WRITER_ACTIVE|OP_PENDING)
1909 
1910 /* Mask of bits a new write cares about */
1911 #define NGQ_WMASK	(NGQ_RMASK|READER_MASK)
1912 
1913 /* Test to decide if there is something on the queue. */
1914 #define QUEUE_ACTIVE(QP) ((QP)->q_flags & OP_PENDING)
1915 
1916 /* How to decide what the next queued item is. */
1917 #define HEAD_IS_READER(QP)  NGI_QUEUED_READER(STAILQ_FIRST(&(QP)->queue))
1918 #define HEAD_IS_WRITER(QP)  NGI_QUEUED_WRITER(STAILQ_FIRST(&(QP)->queue)) /* notused */
1919 
1920 /* Read the status to decide if the next item on the queue can now run. */
1921 #define QUEUED_READER_CAN_PROCEED(QP)			\
1922 		(((QP)->q_flags & (NGQ_RMASK & ~OP_PENDING)) == 0)
1923 #define QUEUED_WRITER_CAN_PROCEED(QP)			\
1924 		(((QP)->q_flags & (NGQ_WMASK & ~OP_PENDING)) == 0)
1925 
1926 /* Is there a chance of getting ANY work off the queue? */
1927 #define NEXT_QUEUED_ITEM_CAN_PROCEED(QP)				\
1928 	((HEAD_IS_READER(QP)) ? QUEUED_READER_CAN_PROCEED(QP) :		\
1929 				QUEUED_WRITER_CAN_PROCEED(QP))
1930 
1931 #define NGQRW_R 0
1932 #define NGQRW_W 1
1933 
1934 #define NGQ2_WORKQ	0x00000001
1935 
1936 /*
1937  * Taking into account the current state of the queue and node, possibly take
1938  * the next entry off the queue and return it. Return NULL if there was
1939  * nothing we could return, either because there really was nothing there, or
1940  * because the node was in a state where it cannot yet process the next item
1941  * on the queue.
1942  */
1943 static __inline item_p
1944 ng_dequeue(node_p node, int *rw)
1945 {
1946 	item_p item;
1947 	struct ng_queue *ngq = &node->nd_input_queue;
1948 
1949 	/* This MUST be called with the mutex held. */
1950 	mtx_assert(&ngq->q_mtx, MA_OWNED);
1951 
1952 	/* If there is nothing queued, then just return. */
1953 	if (!QUEUE_ACTIVE(ngq)) {
1954 		CTR4(KTR_NET, "%20s: node [%x] (%p) queue empty; "
1955 		    "queue flags 0x%lx", __func__,
1956 		    node->nd_ID, node, ngq->q_flags);
1957 		return (NULL);
1958 	}
1959 
1960 	/*
1961 	 * From here, we can assume there is a head item.
1962 	 * We need to find out what it is and if it can be dequeued, given
1963 	 * the current state of the node.
1964 	 */
1965 	if (HEAD_IS_READER(ngq)) {
1966 		while (1) {
1967 			long t = ngq->q_flags;
1968 			if (t & WRITER_ACTIVE) {
1969 				/* There is writer, reader can't proceed. */
1970 				CTR4(KTR_NET, "%20s: node [%x] (%p) queued "
1971 				    "reader can't proceed; queue flags 0x%lx",
1972 				    __func__, node->nd_ID, node, t);
1973 				return (NULL);
1974 			}
1975 			if (atomic_cmpset_acq_int(&ngq->q_flags, t,
1976 			    t + READER_INCREMENT))
1977 				break;
1978 			cpu_spinwait();
1979 		}
1980 		/* We have got reader lock for the node. */
1981 		*rw = NGQRW_R;
1982 	} else if (atomic_cmpset_acq_int(&ngq->q_flags, OP_PENDING,
1983 	    OP_PENDING + WRITER_ACTIVE)) {
1984 		/* We have got writer lock for the node. */
1985 		*rw = NGQRW_W;
1986 	} else {
1987 		/* There is somebody other, writer can't proceed. */
1988 		CTR4(KTR_NET, "%20s: node [%x] (%p) queued writer can't "
1989 		    "proceed; queue flags 0x%lx", __func__, node->nd_ID, node,
1990 		    ngq->q_flags);
1991 		return (NULL);
1992 	}
1993 
1994 	/*
1995 	 * Now we dequeue the request (whatever it may be) and correct the
1996 	 * pending flags and the next and last pointers.
1997 	 */
1998 	item = STAILQ_FIRST(&ngq->queue);
1999 	STAILQ_REMOVE_HEAD(&ngq->queue, el_next);
2000 	if (STAILQ_EMPTY(&ngq->queue))
2001 		atomic_clear_int(&ngq->q_flags, OP_PENDING);
2002 	CTR6(KTR_NET, "%20s: node [%x] (%p) returning item %p as %s; queue "
2003 	    "flags 0x%lx", __func__, node->nd_ID, node, item, *rw ? "WRITER" :
2004 	    "READER", ngq->q_flags);
2005 	return (item);
2006 }
2007 
2008 /*
2009  * Queue a packet to be picked up later by someone else.
2010  * If the queue could be run now, add node to the queue handler's worklist.
2011  */
2012 static __inline void
2013 ng_queue_rw(node_p node, item_p  item, int rw)
2014 {
2015 	struct ng_queue *ngq = &node->nd_input_queue;
2016 	if (rw == NGQRW_W)
2017 		NGI_SET_WRITER(item);
2018 	else
2019 		NGI_SET_READER(item);
2020 	item->depth = 1;
2021 
2022 	NG_QUEUE_LOCK(ngq);
2023 	/* Set OP_PENDING flag and enqueue the item. */
2024 	atomic_set_int(&ngq->q_flags, OP_PENDING);
2025 	STAILQ_INSERT_TAIL(&ngq->queue, item, el_next);
2026 
2027 	CTR5(KTR_NET, "%20s: node [%x] (%p) queued item %p as %s", __func__,
2028 	    node->nd_ID, node, item, rw ? "WRITER" : "READER" );
2029 
2030 	/*
2031 	 * We can take the worklist lock with the node locked
2032 	 * BUT NOT THE REVERSE!
2033 	 */
2034 	if (NEXT_QUEUED_ITEM_CAN_PROCEED(ngq))
2035 		ng_worklist_add(node);
2036 	NG_QUEUE_UNLOCK(ngq);
2037 }
2038 
2039 /* Acquire reader lock on node. If node is busy, queue the packet. */
2040 static __inline item_p
2041 ng_acquire_read(node_p node, item_p item)
2042 {
2043 	KASSERT(node != &ng_deadnode,
2044 	    ("%s: working on deadnode", __func__));
2045 
2046 	/* Reader needs node without writer and pending items. */
2047 	for (;;) {
2048 		long t = node->nd_input_queue.q_flags;
2049 		if (t & NGQ_RMASK)
2050 			break; /* Node is not ready for reader. */
2051 		if (atomic_cmpset_acq_int(&node->nd_input_queue.q_flags, t,
2052 		    t + READER_INCREMENT)) {
2053 	    		/* Successfully grabbed node */
2054 			CTR4(KTR_NET, "%20s: node [%x] (%p) acquired item %p",
2055 			    __func__, node->nd_ID, node, item);
2056 			return (item);
2057 		}
2058 		cpu_spinwait();
2059 	}
2060 
2061 	/* Queue the request for later. */
2062 	ng_queue_rw(node, item, NGQRW_R);
2063 
2064 	return (NULL);
2065 }
2066 
2067 /* Acquire writer lock on node. If node is busy, queue the packet. */
2068 static __inline item_p
2069 ng_acquire_write(node_p node, item_p item)
2070 {
2071 	KASSERT(node != &ng_deadnode,
2072 	    ("%s: working on deadnode", __func__));
2073 
2074 	/* Writer needs completely idle node. */
2075 	if (atomic_cmpset_acq_int(&node->nd_input_queue.q_flags, 0,
2076 	    WRITER_ACTIVE)) {
2077 	    	/* Successfully grabbed node */
2078 		CTR4(KTR_NET, "%20s: node [%x] (%p) acquired item %p",
2079 		    __func__, node->nd_ID, node, item);
2080 		return (item);
2081 	}
2082 
2083 	/* Queue the request for later. */
2084 	ng_queue_rw(node, item, NGQRW_W);
2085 
2086 	return (NULL);
2087 }
2088 
2089 #if 0
2090 static __inline item_p
2091 ng_upgrade_write(node_p node, item_p item)
2092 {
2093 	struct ng_queue *ngq = &node->nd_input_queue;
2094 	KASSERT(node != &ng_deadnode,
2095 	    ("%s: working on deadnode", __func__));
2096 
2097 	NGI_SET_WRITER(item);
2098 
2099 	NG_QUEUE_LOCK(ngq);
2100 
2101 	/*
2102 	 * There will never be no readers as we are there ourselves.
2103 	 * Set the WRITER_ACTIVE flags ASAP to block out fast track readers.
2104 	 * The caller we are running from will call ng_leave_read()
2105 	 * soon, so we must account for that. We must leave again with the
2106 	 * READER lock. If we find other readers, then
2107 	 * queue the request for later. However "later" may be rignt now
2108 	 * if there are no readers. We don't really care if there are queued
2109 	 * items as we will bypass them anyhow.
2110 	 */
2111 	atomic_add_int(&ngq->q_flags, WRITER_ACTIVE - READER_INCREMENT);
2112 	if ((ngq->q_flags & (NGQ_WMASK & ~OP_PENDING)) == WRITER_ACTIVE) {
2113 		NG_QUEUE_UNLOCK(ngq);
2114 
2115 		/* It's just us, act on the item. */
2116 		/* will NOT drop writer lock when done */
2117 		ng_apply_item(node, item, 0);
2118 
2119 		/*
2120 		 * Having acted on the item, atomically
2121 		 * downgrade back to READER and finish up.
2122 	 	 */
2123 		atomic_add_int(&ngq->q_flags, READER_INCREMENT - WRITER_ACTIVE);
2124 
2125 		/* Our caller will call ng_leave_read() */
2126 		return;
2127 	}
2128 	/*
2129 	 * It's not just us active, so queue us AT THE HEAD.
2130 	 * "Why?" I hear you ask.
2131 	 * Put us at the head of the queue as we've already been
2132 	 * through it once. If there is nothing else waiting,
2133 	 * set the correct flags.
2134 	 */
2135 	if (STAILQ_EMPTY(&ngq->queue)) {
2136 		/* We've gone from, 0 to 1 item in the queue */
2137 		atomic_set_int(&ngq->q_flags, OP_PENDING);
2138 
2139 		CTR3(KTR_NET, "%20s: node [%x] (%p) set OP_PENDING", __func__,
2140 		    node->nd_ID, node);
2141 	};
2142 	STAILQ_INSERT_HEAD(&ngq->queue, item, el_next);
2143 	CTR4(KTR_NET, "%20s: node [%x] (%p) requeued item %p as WRITER",
2144 	    __func__, node->nd_ID, node, item );
2145 
2146 	/* Reverse what we did above. That downgrades us back to reader */
2147 	atomic_add_int(&ngq->q_flags, READER_INCREMENT - WRITER_ACTIVE);
2148 	if (QUEUE_ACTIVE(ngq) && NEXT_QUEUED_ITEM_CAN_PROCEED(ngq))
2149 		ng_worklist_add(node);
2150 	NG_QUEUE_UNLOCK(ngq);
2151 
2152 	return;
2153 }
2154 #endif
2155 
2156 /* Release reader lock. */
2157 static __inline void
2158 ng_leave_read(node_p node)
2159 {
2160 	atomic_subtract_rel_int(&node->nd_input_queue.q_flags, READER_INCREMENT);
2161 }
2162 
2163 /* Release writer lock. */
2164 static __inline void
2165 ng_leave_write(node_p node)
2166 {
2167 	atomic_clear_rel_int(&node->nd_input_queue.q_flags, WRITER_ACTIVE);
2168 }
2169 
2170 /* Purge node queue. Called on node shutdown. */
2171 static void
2172 ng_flush_input_queue(node_p node)
2173 {
2174 	struct ng_queue *ngq = &node->nd_input_queue;
2175 	item_p item;
2176 
2177 	NG_QUEUE_LOCK(ngq);
2178 	while ((item = STAILQ_FIRST(&ngq->queue)) != NULL) {
2179 		STAILQ_REMOVE_HEAD(&ngq->queue, el_next);
2180 		if (STAILQ_EMPTY(&ngq->queue))
2181 			atomic_clear_int(&ngq->q_flags, OP_PENDING);
2182 		NG_QUEUE_UNLOCK(ngq);
2183 
2184 		/* If the item is supplying a callback, call it with an error */
2185 		if (item->apply != NULL) {
2186 			if (item->depth == 1)
2187 				item->apply->error = ENOENT;
2188 			if (refcount_release(&item->apply->refs)) {
2189 				(*item->apply->apply)(item->apply->context,
2190 				    item->apply->error);
2191 			}
2192 		}
2193 		NG_FREE_ITEM(item);
2194 		NG_QUEUE_LOCK(ngq);
2195 	}
2196 	NG_QUEUE_UNLOCK(ngq);
2197 }
2198 
2199 /***********************************************************************
2200 * Externally visible method for sending or queueing messages or data.
2201 ***********************************************************************/
2202 
2203 /*
2204  * The module code should have filled out the item correctly by this stage:
2205  * Common:
2206  *    reference to destination node.
2207  *    Reference to destination rcv hook if relevant.
2208  *    apply pointer must be or NULL or reference valid struct ng_apply_info.
2209  * Data:
2210  *    pointer to mbuf
2211  * Control_Message:
2212  *    pointer to msg.
2213  *    ID of original sender node. (return address)
2214  * Function:
2215  *    Function pointer
2216  *    void * argument
2217  *    integer argument
2218  *
2219  * The nodes have several routines and macros to help with this task:
2220  */
2221 
2222 int
2223 ng_snd_item(item_p item, int flags)
2224 {
2225 	hook_p hook;
2226 	node_p node;
2227 	int queue, rw;
2228 	struct ng_queue *ngq;
2229 	int error = 0;
2230 
2231 	/* We are sending item, so it must be present! */
2232 	KASSERT(item != NULL, ("ng_snd_item: item is NULL"));
2233 
2234 #ifdef	NETGRAPH_DEBUG
2235 	_ngi_check(item, __FILE__, __LINE__);
2236 #endif
2237 
2238 	/* Item was sent once more, postpone apply() call. */
2239 	if (item->apply)
2240 		refcount_acquire(&item->apply->refs);
2241 
2242 	node = NGI_NODE(item);
2243 	/* Node is never optional. */
2244 	KASSERT(node != NULL, ("ng_snd_item: node is NULL"));
2245 
2246 	hook = NGI_HOOK(item);
2247 	/* Valid hook and mbuf are mandatory for data. */
2248 	if ((item->el_flags & NGQF_TYPE) == NGQF_DATA) {
2249 		KASSERT(hook != NULL, ("ng_snd_item: hook for data is NULL"));
2250 		if (NGI_M(item) == NULL)
2251 			ERROUT(EINVAL);
2252 		CHECK_DATA_MBUF(NGI_M(item));
2253 	}
2254 
2255 	/*
2256 	 * If the item or the node specifies single threading, force
2257 	 * writer semantics. Similarly, the node may say one hook always
2258 	 * produces writers. These are overrides.
2259 	 */
2260 	if (((item->el_flags & NGQF_RW) == NGQF_WRITER) ||
2261 	    (node->nd_flags & NGF_FORCE_WRITER) ||
2262 	    (hook && (hook->hk_flags & HK_FORCE_WRITER))) {
2263 		rw = NGQRW_W;
2264 	} else {
2265 		rw = NGQRW_R;
2266 	}
2267 
2268 	/*
2269 	 * If sender or receiver requests queued delivery, or call graph
2270 	 * loops back from outbound to inbound path, or stack usage
2271 	 * level is dangerous - enqueue message.
2272 	 */
2273 	if ((flags & NG_QUEUE) || (hook && (hook->hk_flags & HK_QUEUE))) {
2274 		queue = 1;
2275 	} else if (hook && (hook->hk_flags & HK_TO_INBOUND) &&
2276 	    curthread->td_ng_outbound) {
2277 		queue = 1;
2278 	} else {
2279 		queue = 0;
2280 #ifdef GET_STACK_USAGE
2281 		/*
2282 		 * Most of netgraph nodes have small stack consumption and
2283 		 * for them 25% of free stack space is more than enough.
2284 		 * Nodes/hooks with higher stack usage should be marked as
2285 		 * HI_STACK. For them 50% of stack will be guaranteed then.
2286 		 * XXX: Values 25% and 50% are completely empirical.
2287 		 */
2288 		size_t	st, su, sl;
2289 		GET_STACK_USAGE(st, su);
2290 		sl = st - su;
2291 		if ((sl * 4 < st) || ((sl * 2 < st) &&
2292 		    ((node->nd_flags & NGF_HI_STACK) || (hook &&
2293 		    (hook->hk_flags & HK_HI_STACK)))))
2294 			queue = 1;
2295 #endif
2296 	}
2297 
2298 	if (queue) {
2299 		/* Put it on the queue for that node*/
2300 		ng_queue_rw(node, item, rw);
2301 		return ((flags & NG_PROGRESS) ? EINPROGRESS : 0);
2302 	}
2303 
2304 	/*
2305 	 * We already decided how we will be queueud or treated.
2306 	 * Try get the appropriate operating permission.
2307 	 */
2308  	if (rw == NGQRW_R)
2309 		item = ng_acquire_read(node, item);
2310 	else
2311 		item = ng_acquire_write(node, item);
2312 
2313 	/* Item was queued while trying to get permission. */
2314 	if (item == NULL)
2315 		return ((flags & NG_PROGRESS) ? EINPROGRESS : 0);
2316 
2317 	NGI_GET_NODE(item, node); /* zaps stored node */
2318 
2319 	item->depth++;
2320 	error = ng_apply_item(node, item, rw); /* drops r/w lock when done */
2321 
2322 	/* If something is waiting on queue and ready, schedule it. */
2323 	ngq = &node->nd_input_queue;
2324 	if (QUEUE_ACTIVE(ngq)) {
2325 		NG_QUEUE_LOCK(ngq);
2326 		if (QUEUE_ACTIVE(ngq) && NEXT_QUEUED_ITEM_CAN_PROCEED(ngq))
2327 			ng_worklist_add(node);
2328 		NG_QUEUE_UNLOCK(ngq);
2329 	}
2330 
2331 	/*
2332 	 * Node may go away as soon as we remove the reference.
2333 	 * Whatever we do, DO NOT access the node again!
2334 	 */
2335 	NG_NODE_UNREF(node);
2336 
2337 	return (error);
2338 
2339 done:
2340 	/* If was not sent, apply callback here. */
2341 	if (item->apply != NULL) {
2342 		if (item->depth == 0 && error != 0)
2343 			item->apply->error = error;
2344 		if (refcount_release(&item->apply->refs)) {
2345 			(*item->apply->apply)(item->apply->context,
2346 			    item->apply->error);
2347 		}
2348 	}
2349 
2350 	NG_FREE_ITEM(item);
2351 	return (error);
2352 }
2353 
2354 /*
2355  * We have an item that was possibly queued somewhere.
2356  * It should contain all the information needed
2357  * to run it on the appropriate node/hook.
2358  * If there is apply pointer and we own the last reference, call apply().
2359  */
2360 static int
2361 ng_apply_item(node_p node, item_p item, int rw)
2362 {
2363 	hook_p  hook;
2364 	ng_rcvdata_t *rcvdata;
2365 	ng_rcvmsg_t *rcvmsg;
2366 	struct ng_apply_info *apply;
2367 	int	error = 0, depth;
2368 
2369 	/* Node and item are never optional. */
2370 	KASSERT(node != NULL, ("ng_apply_item: node is NULL"));
2371 	KASSERT(item != NULL, ("ng_apply_item: item is NULL"));
2372 
2373 	NGI_GET_HOOK(item, hook); /* clears stored hook */
2374 #ifdef	NETGRAPH_DEBUG
2375 	_ngi_check(item, __FILE__, __LINE__);
2376 #endif
2377 
2378 	apply = item->apply;
2379 	depth = item->depth;
2380 
2381 	switch (item->el_flags & NGQF_TYPE) {
2382 	case NGQF_DATA:
2383 		/*
2384 		 * Check things are still ok as when we were queued.
2385 		 */
2386 		KASSERT(hook != NULL, ("ng_apply_item: hook for data is NULL"));
2387 		if (NG_HOOK_NOT_VALID(hook) ||
2388 		    NG_NODE_NOT_VALID(node)) {
2389 			error = EIO;
2390 			NG_FREE_ITEM(item);
2391 			break;
2392 		}
2393 		/*
2394 		 * If no receive method, just silently drop it.
2395 		 * Give preference to the hook over-ride method.
2396 		 */
2397 		if ((!(rcvdata = hook->hk_rcvdata)) &&
2398 		    (!(rcvdata = NG_HOOK_NODE(hook)->nd_type->rcvdata))) {
2399 			error = 0;
2400 			NG_FREE_ITEM(item);
2401 			break;
2402 		}
2403 		error = (*rcvdata)(hook, item);
2404 		break;
2405 	case NGQF_MESG:
2406 		if (hook && NG_HOOK_NOT_VALID(hook)) {
2407 			/*
2408 			 * The hook has been zapped then we can't use it.
2409 			 * Immediately drop its reference.
2410 			 * The message may not need it.
2411 			 */
2412 			NG_HOOK_UNREF(hook);
2413 			hook = NULL;
2414 		}
2415 		/*
2416 		 * Similarly, if the node is a zombie there is
2417 		 * nothing we can do with it, drop everything.
2418 		 */
2419 		if (NG_NODE_NOT_VALID(node)) {
2420 			TRAP_ERROR();
2421 			error = EINVAL;
2422 			NG_FREE_ITEM(item);
2423 			break;
2424 		}
2425 		/*
2426 		 * Call the appropriate message handler for the object.
2427 		 * It is up to the message handler to free the message.
2428 		 * If it's a generic message, handle it generically,
2429 		 * otherwise call the type's message handler (if it exists).
2430 		 * XXX (race). Remember that a queued message may
2431 		 * reference a node or hook that has just been
2432 		 * invalidated. It will exist as the queue code
2433 		 * is holding a reference, but..
2434 		 */
2435 		if ((NGI_MSG(item)->header.typecookie == NGM_GENERIC_COOKIE) &&
2436 		    ((NGI_MSG(item)->header.flags & NGF_RESP) == 0)) {
2437 			error = ng_generic_msg(node, item, hook);
2438 			break;
2439 		}
2440 		if (((!hook) || (!(rcvmsg = hook->hk_rcvmsg))) &&
2441 		    (!(rcvmsg = node->nd_type->rcvmsg))) {
2442 			TRAP_ERROR();
2443 			error = 0;
2444 			NG_FREE_ITEM(item);
2445 			break;
2446 		}
2447 		error = (*rcvmsg)(node, item, hook);
2448 		break;
2449 	case NGQF_FN:
2450 	case NGQF_FN2:
2451 		/*
2452 		 * In the case of the shutdown message we allow it to hit
2453 		 * even if the node is invalid.
2454 		 */
2455 		if (NG_NODE_NOT_VALID(node) &&
2456 		    NGI_FN(item) != &ng_rmnode) {
2457 			TRAP_ERROR();
2458 			error = EINVAL;
2459 			NG_FREE_ITEM(item);
2460 			break;
2461 		}
2462 		/* Same is about some internal functions and invalid hook. */
2463 		if (hook && NG_HOOK_NOT_VALID(hook) &&
2464 		    NGI_FN2(item) != &ng_con_part2 &&
2465 		    NGI_FN2(item) != &ng_con_part3 &&
2466 		    NGI_FN(item) != &ng_rmhook_part2) {
2467 			TRAP_ERROR();
2468 			error = EINVAL;
2469 			NG_FREE_ITEM(item);
2470 			break;
2471 		}
2472 
2473 		if ((item->el_flags & NGQF_TYPE) == NGQF_FN) {
2474 			(*NGI_FN(item))(node, hook, NGI_ARG1(item),
2475 			    NGI_ARG2(item));
2476 			NG_FREE_ITEM(item);
2477 		} else	/* it is NGQF_FN2 */
2478 			error = (*NGI_FN2(item))(node, item, hook);
2479 		break;
2480 	}
2481 	/*
2482 	 * We held references on some of the resources
2483 	 * that we took from the item. Now that we have
2484 	 * finished doing everything, drop those references.
2485 	 */
2486 	if (hook)
2487 		NG_HOOK_UNREF(hook);
2488 
2489  	if (rw == NGQRW_R)
2490 		ng_leave_read(node);
2491 	else
2492 		ng_leave_write(node);
2493 
2494 	/* Apply callback. */
2495 	if (apply != NULL) {
2496 		if (depth == 1 && error != 0)
2497 			apply->error = error;
2498 		if (refcount_release(&apply->refs))
2499 			(*apply->apply)(apply->context, apply->error);
2500 	}
2501 
2502 	return (error);
2503 }
2504 
2505 /***********************************************************************
2506  * Implement the 'generic' control messages
2507  ***********************************************************************/
2508 static int
2509 ng_generic_msg(node_p here, item_p item, hook_p lasthook)
2510 {
2511 	int error = 0;
2512 	struct ng_mesg *msg;
2513 	struct ng_mesg *resp = NULL;
2514 
2515 	NGI_GET_MSG(item, msg);
2516 	if (msg->header.typecookie != NGM_GENERIC_COOKIE) {
2517 		TRAP_ERROR();
2518 		error = EINVAL;
2519 		goto out;
2520 	}
2521 	switch (msg->header.cmd) {
2522 	case NGM_SHUTDOWN:
2523 		ng_rmnode(here, NULL, NULL, 0);
2524 		break;
2525 	case NGM_MKPEER:
2526 	    {
2527 		struct ngm_mkpeer *const mkp = (struct ngm_mkpeer *) msg->data;
2528 
2529 		if (msg->header.arglen != sizeof(*mkp)) {
2530 			TRAP_ERROR();
2531 			error = EINVAL;
2532 			break;
2533 		}
2534 		mkp->type[sizeof(mkp->type) - 1] = '\0';
2535 		mkp->ourhook[sizeof(mkp->ourhook) - 1] = '\0';
2536 		mkp->peerhook[sizeof(mkp->peerhook) - 1] = '\0';
2537 		error = ng_mkpeer(here, mkp->ourhook, mkp->peerhook, mkp->type);
2538 		break;
2539 	    }
2540 	case NGM_CONNECT:
2541 	    {
2542 		struct ngm_connect *const con =
2543 			(struct ngm_connect *) msg->data;
2544 		node_p node2;
2545 
2546 		if (msg->header.arglen != sizeof(*con)) {
2547 			TRAP_ERROR();
2548 			error = EINVAL;
2549 			break;
2550 		}
2551 		con->path[sizeof(con->path) - 1] = '\0';
2552 		con->ourhook[sizeof(con->ourhook) - 1] = '\0';
2553 		con->peerhook[sizeof(con->peerhook) - 1] = '\0';
2554 		/* Don't forget we get a reference.. */
2555 		error = ng_path2noderef(here, con->path, &node2, NULL);
2556 		if (error)
2557 			break;
2558 		error = ng_con_nodes(item, here, con->ourhook,
2559 		    node2, con->peerhook);
2560 		NG_NODE_UNREF(node2);
2561 		break;
2562 	    }
2563 	case NGM_NAME:
2564 	    {
2565 		struct ngm_name *const nam = (struct ngm_name *) msg->data;
2566 
2567 		if (msg->header.arglen != sizeof(*nam)) {
2568 			TRAP_ERROR();
2569 			error = EINVAL;
2570 			break;
2571 		}
2572 		nam->name[sizeof(nam->name) - 1] = '\0';
2573 		error = ng_name_node(here, nam->name);
2574 		break;
2575 	    }
2576 	case NGM_RMHOOK:
2577 	    {
2578 		struct ngm_rmhook *const rmh = (struct ngm_rmhook *) msg->data;
2579 		hook_p hook;
2580 
2581 		if (msg->header.arglen != sizeof(*rmh)) {
2582 			TRAP_ERROR();
2583 			error = EINVAL;
2584 			break;
2585 		}
2586 		rmh->ourhook[sizeof(rmh->ourhook) - 1] = '\0';
2587 		if ((hook = ng_findhook(here, rmh->ourhook)) != NULL)
2588 			ng_destroy_hook(hook);
2589 		break;
2590 	    }
2591 	case NGM_NODEINFO:
2592 	    {
2593 		struct nodeinfo *ni;
2594 
2595 		NG_MKRESPONSE(resp, msg, sizeof(*ni), M_NOWAIT);
2596 		if (resp == NULL) {
2597 			error = ENOMEM;
2598 			break;
2599 		}
2600 
2601 		/* Fill in node info */
2602 		ni = (struct nodeinfo *) resp->data;
2603 		if (NG_NODE_HAS_NAME(here))
2604 			strcpy(ni->name, NG_NODE_NAME(here));
2605 		strcpy(ni->type, here->nd_type->name);
2606 		ni->id = ng_node2ID(here);
2607 		ni->hooks = here->nd_numhooks;
2608 		break;
2609 	    }
2610 	case NGM_LISTHOOKS:
2611 	    {
2612 		const int nhooks = here->nd_numhooks;
2613 		struct hooklist *hl;
2614 		struct nodeinfo *ni;
2615 		hook_p hook;
2616 
2617 		/* Get response struct */
2618 		NG_MKRESPONSE(resp, msg, sizeof(*hl) +
2619 		    (nhooks * sizeof(struct linkinfo)), M_NOWAIT);
2620 		if (resp == NULL) {
2621 			error = ENOMEM;
2622 			break;
2623 		}
2624 		hl = (struct hooklist *) resp->data;
2625 		ni = &hl->nodeinfo;
2626 
2627 		/* Fill in node info */
2628 		if (NG_NODE_HAS_NAME(here))
2629 			strcpy(ni->name, NG_NODE_NAME(here));
2630 		strcpy(ni->type, here->nd_type->name);
2631 		ni->id = ng_node2ID(here);
2632 
2633 		/* Cycle through the linked list of hooks */
2634 		ni->hooks = 0;
2635 		LIST_FOREACH(hook, &here->nd_hooks, hk_hooks) {
2636 			struct linkinfo *const link = &hl->link[ni->hooks];
2637 
2638 			if (ni->hooks >= nhooks) {
2639 				log(LOG_ERR, "%s: number of %s changed\n",
2640 				    __func__, "hooks");
2641 				break;
2642 			}
2643 			if (NG_HOOK_NOT_VALID(hook))
2644 				continue;
2645 			strcpy(link->ourhook, NG_HOOK_NAME(hook));
2646 			strcpy(link->peerhook, NG_PEER_HOOK_NAME(hook));
2647 			if (NG_PEER_NODE_NAME(hook)[0] != '\0')
2648 				strcpy(link->nodeinfo.name,
2649 				    NG_PEER_NODE_NAME(hook));
2650 			strcpy(link->nodeinfo.type,
2651 			   NG_PEER_NODE(hook)->nd_type->name);
2652 			link->nodeinfo.id = ng_node2ID(NG_PEER_NODE(hook));
2653 			link->nodeinfo.hooks = NG_PEER_NODE(hook)->nd_numhooks;
2654 			ni->hooks++;
2655 		}
2656 		break;
2657 	    }
2658 
2659 	case NGM_LISTNODES:
2660 	    {
2661 		struct namelist *nl;
2662 		node_p node;
2663 		int i;
2664 
2665 		IDHASH_RLOCK();
2666 		/* Get response struct. */
2667 		NG_MKRESPONSE(resp, msg, sizeof(*nl) +
2668 		    (V_ng_nodes * sizeof(struct nodeinfo)), M_NOWAIT);
2669 		if (resp == NULL) {
2670 			IDHASH_RUNLOCK();
2671 			error = ENOMEM;
2672 			break;
2673 		}
2674 		nl = (struct namelist *) resp->data;
2675 
2676 		/* Cycle through the lists of nodes. */
2677 		nl->numnames = 0;
2678 		for (i = 0; i <= V_ng_ID_hmask; i++) {
2679 			LIST_FOREACH(node, &V_ng_ID_hash[i], nd_idnodes) {
2680 				struct nodeinfo *const np =
2681 				    &nl->nodeinfo[nl->numnames];
2682 
2683 				if (NG_NODE_NOT_VALID(node))
2684 					continue;
2685 				if (NG_NODE_HAS_NAME(node))
2686 					strcpy(np->name, NG_NODE_NAME(node));
2687 				strcpy(np->type, node->nd_type->name);
2688 				np->id = ng_node2ID(node);
2689 				np->hooks = node->nd_numhooks;
2690 				KASSERT(nl->numnames < V_ng_nodes,
2691 				    ("%s: no space", __func__));
2692 				nl->numnames++;
2693 			}
2694 		}
2695 		IDHASH_RUNLOCK();
2696 		break;
2697 	    }
2698 	case NGM_LISTNAMES:
2699 	    {
2700 		struct namelist *nl;
2701 		node_p node;
2702 		int i;
2703 
2704 		NAMEHASH_RLOCK();
2705 		/* Get response struct. */
2706 		NG_MKRESPONSE(resp, msg, sizeof(*nl) +
2707 		    (V_ng_named_nodes * sizeof(struct nodeinfo)), M_NOWAIT);
2708 		if (resp == NULL) {
2709 			NAMEHASH_RUNLOCK();
2710 			error = ENOMEM;
2711 			break;
2712 		}
2713 		nl = (struct namelist *) resp->data;
2714 
2715 		/* Cycle through the lists of nodes. */
2716 		nl->numnames = 0;
2717 		for (i = 0; i <= V_ng_name_hmask; i++) {
2718 			LIST_FOREACH(node, &V_ng_name_hash[i], nd_nodes) {
2719 				struct nodeinfo *const np =
2720 				    &nl->nodeinfo[nl->numnames];
2721 
2722 				if (NG_NODE_NOT_VALID(node))
2723 					continue;
2724 				strcpy(np->name, NG_NODE_NAME(node));
2725 				strcpy(np->type, node->nd_type->name);
2726 				np->id = ng_node2ID(node);
2727 				np->hooks = node->nd_numhooks;
2728 				KASSERT(nl->numnames < V_ng_named_nodes,
2729 				    ("%s: no space", __func__));
2730 				nl->numnames++;
2731 			}
2732 		}
2733 		NAMEHASH_RUNLOCK();
2734 		break;
2735 	    }
2736 
2737 	case NGM_LISTTYPES:
2738 	    {
2739 		struct typelist *tl;
2740 		struct ng_type *type;
2741 		int num = 0;
2742 
2743 		TYPELIST_RLOCK();
2744 		/* Count number of types */
2745 		LIST_FOREACH(type, &ng_typelist, types)
2746 			num++;
2747 
2748 		/* Get response struct */
2749 		NG_MKRESPONSE(resp, msg, sizeof(*tl) +
2750 		    (num * sizeof(struct typeinfo)), M_NOWAIT);
2751 		if (resp == NULL) {
2752 			TYPELIST_RUNLOCK();
2753 			error = ENOMEM;
2754 			break;
2755 		}
2756 		tl = (struct typelist *) resp->data;
2757 
2758 		/* Cycle through the linked list of types */
2759 		tl->numtypes = 0;
2760 		LIST_FOREACH(type, &ng_typelist, types) {
2761 			struct typeinfo *const tp = &tl->typeinfo[tl->numtypes];
2762 
2763 			strcpy(tp->type_name, type->name);
2764 			tp->numnodes = type->refs - 1; /* don't count list */
2765 			KASSERT(tl->numtypes < num, ("%s: no space", __func__));
2766 			tl->numtypes++;
2767 		}
2768 		TYPELIST_RUNLOCK();
2769 		break;
2770 	    }
2771 
2772 	case NGM_BINARY2ASCII:
2773 	    {
2774 		int bufSize = 1024;
2775 		const struct ng_parse_type *argstype;
2776 		const struct ng_cmdlist *c;
2777 		struct ng_mesg *binary, *ascii;
2778 
2779 		/* Data area must contain a valid netgraph message */
2780 		binary = (struct ng_mesg *)msg->data;
2781 		if (msg->header.arglen < sizeof(struct ng_mesg) ||
2782 		    (msg->header.arglen - sizeof(struct ng_mesg) <
2783 		    binary->header.arglen)) {
2784 			TRAP_ERROR();
2785 			error = EINVAL;
2786 			break;
2787 		}
2788 retry_b2a:
2789 		/* Get a response message with lots of room */
2790 		NG_MKRESPONSE(resp, msg, sizeof(*ascii) + bufSize, M_NOWAIT);
2791 		if (resp == NULL) {
2792 			error = ENOMEM;
2793 			break;
2794 		}
2795 		ascii = (struct ng_mesg *)resp->data;
2796 
2797 		/* Copy binary message header to response message payload */
2798 		bcopy(binary, ascii, sizeof(*binary));
2799 
2800 		/* Find command by matching typecookie and command number */
2801 		for (c = here->nd_type->cmdlist; c != NULL && c->name != NULL;
2802 		    c++) {
2803 			if (binary->header.typecookie == c->cookie &&
2804 			    binary->header.cmd == c->cmd)
2805 				break;
2806 		}
2807 		if (c == NULL || c->name == NULL) {
2808 			for (c = ng_generic_cmds; c->name != NULL; c++) {
2809 				if (binary->header.typecookie == c->cookie &&
2810 				    binary->header.cmd == c->cmd)
2811 					break;
2812 			}
2813 			if (c->name == NULL) {
2814 				NG_FREE_MSG(resp);
2815 				error = ENOSYS;
2816 				break;
2817 			}
2818 		}
2819 
2820 		/* Convert command name to ASCII */
2821 		snprintf(ascii->header.cmdstr, sizeof(ascii->header.cmdstr),
2822 		    "%s", c->name);
2823 
2824 		/* Convert command arguments to ASCII */
2825 		argstype = (binary->header.flags & NGF_RESP) ?
2826 		    c->respType : c->mesgType;
2827 		if (argstype == NULL) {
2828 			*ascii->data = '\0';
2829 		} else {
2830 			error = ng_unparse(argstype, (u_char *)binary->data,
2831 			    ascii->data, bufSize);
2832 			if (error == ERANGE) {
2833 				NG_FREE_MSG(resp);
2834 				bufSize *= 2;
2835 				goto retry_b2a;
2836 			} else if (error) {
2837 				NG_FREE_MSG(resp);
2838 				break;
2839 			}
2840 		}
2841 
2842 		/* Return the result as struct ng_mesg plus ASCII string */
2843 		bufSize = strlen(ascii->data) + 1;
2844 		ascii->header.arglen = bufSize;
2845 		resp->header.arglen = sizeof(*ascii) + bufSize;
2846 		break;
2847 	    }
2848 
2849 	case NGM_ASCII2BINARY:
2850 	    {
2851 		int bufSize = 20 * 1024;	/* XXX hard coded constant */
2852 		const struct ng_cmdlist *c;
2853 		const struct ng_parse_type *argstype;
2854 		struct ng_mesg *ascii, *binary;
2855 		int off = 0;
2856 
2857 		/* Data area must contain at least a struct ng_mesg + '\0' */
2858 		ascii = (struct ng_mesg *)msg->data;
2859 		if ((msg->header.arglen < sizeof(*ascii) + 1) ||
2860 		    (ascii->header.arglen < 1) ||
2861 		    (msg->header.arglen < sizeof(*ascii) +
2862 		    ascii->header.arglen)) {
2863 			TRAP_ERROR();
2864 			error = EINVAL;
2865 			break;
2866 		}
2867 		ascii->data[ascii->header.arglen - 1] = '\0';
2868 
2869 		/* Get a response message with lots of room */
2870 		NG_MKRESPONSE(resp, msg, sizeof(*binary) + bufSize, M_NOWAIT);
2871 		if (resp == NULL) {
2872 			error = ENOMEM;
2873 			break;
2874 		}
2875 		binary = (struct ng_mesg *)resp->data;
2876 
2877 		/* Copy ASCII message header to response message payload */
2878 		bcopy(ascii, binary, sizeof(*ascii));
2879 
2880 		/* Find command by matching ASCII command string */
2881 		for (c = here->nd_type->cmdlist;
2882 		    c != NULL && c->name != NULL; c++) {
2883 			if (strcmp(ascii->header.cmdstr, c->name) == 0)
2884 				break;
2885 		}
2886 		if (c == NULL || c->name == NULL) {
2887 			for (c = ng_generic_cmds; c->name != NULL; c++) {
2888 				if (strcmp(ascii->header.cmdstr, c->name) == 0)
2889 					break;
2890 			}
2891 			if (c->name == NULL) {
2892 				NG_FREE_MSG(resp);
2893 				error = ENOSYS;
2894 				break;
2895 			}
2896 		}
2897 
2898 		/* Convert command name to binary */
2899 		binary->header.cmd = c->cmd;
2900 		binary->header.typecookie = c->cookie;
2901 
2902 		/* Convert command arguments to binary */
2903 		argstype = (binary->header.flags & NGF_RESP) ?
2904 		    c->respType : c->mesgType;
2905 		if (argstype == NULL) {
2906 			bufSize = 0;
2907 		} else {
2908 			if ((error = ng_parse(argstype, ascii->data, &off,
2909 			    (u_char *)binary->data, &bufSize)) != 0) {
2910 				NG_FREE_MSG(resp);
2911 				break;
2912 			}
2913 		}
2914 
2915 		/* Return the result */
2916 		binary->header.arglen = bufSize;
2917 		resp->header.arglen = sizeof(*binary) + bufSize;
2918 		break;
2919 	    }
2920 
2921 	case NGM_TEXT_CONFIG:
2922 	case NGM_TEXT_STATUS:
2923 		/*
2924 		 * This one is tricky as it passes the command down to the
2925 		 * actual node, even though it is a generic type command.
2926 		 * This means we must assume that the item/msg is already freed
2927 		 * when control passes back to us.
2928 		 */
2929 		if (here->nd_type->rcvmsg != NULL) {
2930 			NGI_MSG(item) = msg; /* put it back as we found it */
2931 			return((*here->nd_type->rcvmsg)(here, item, lasthook));
2932 		}
2933 		/* Fall through if rcvmsg not supported */
2934 	default:
2935 		TRAP_ERROR();
2936 		error = EINVAL;
2937 	}
2938 	/*
2939 	 * Sometimes a generic message may be statically allocated
2940 	 * to avoid problems with allocating when in tight memory situations.
2941 	 * Don't free it if it is so.
2942 	 * I break them apart here, because erros may cause a free if the item
2943 	 * in which case we'd be doing it twice.
2944 	 * they are kept together above, to simplify freeing.
2945 	 */
2946 out:
2947 	NG_RESPOND_MSG(error, here, item, resp);
2948 	NG_FREE_MSG(msg);
2949 	return (error);
2950 }
2951 
2952 /************************************************************************
2953 			Queue element get/free routines
2954 ************************************************************************/
2955 
2956 uma_zone_t			ng_qzone;
2957 uma_zone_t			ng_qdzone;
2958 static int			numthreads = 0; /* number of queue threads */
2959 static int			maxalloc = 4096;/* limit the damage of a leak */
2960 static int			maxdata = 4096;	/* limit the damage of a DoS */
2961 
2962 SYSCTL_INT(_net_graph, OID_AUTO, threads, CTLFLAG_RDTUN, &numthreads,
2963     0, "Number of queue processing threads");
2964 SYSCTL_INT(_net_graph, OID_AUTO, maxalloc, CTLFLAG_RDTUN, &maxalloc,
2965     0, "Maximum number of non-data queue items to allocate");
2966 SYSCTL_INT(_net_graph, OID_AUTO, maxdata, CTLFLAG_RDTUN, &maxdata,
2967     0, "Maximum number of data queue items to allocate");
2968 
2969 #ifdef	NETGRAPH_DEBUG
2970 static TAILQ_HEAD(, ng_item) ng_itemlist = TAILQ_HEAD_INITIALIZER(ng_itemlist);
2971 static int allocated;	/* number of items malloc'd */
2972 #endif
2973 
2974 /*
2975  * Get a queue entry.
2976  * This is usually called when a packet first enters netgraph.
2977  * By definition, this is usually from an interrupt, or from a user.
2978  * Users are not so important, but try be quick for the times that it's
2979  * an interrupt.
2980  */
2981 static __inline item_p
2982 ng_alloc_item(int type, int flags)
2983 {
2984 	item_p item;
2985 
2986 	KASSERT(((type & ~NGQF_TYPE) == 0),
2987 	    ("%s: incorrect item type: %d", __func__, type));
2988 
2989 	item = uma_zalloc((type == NGQF_DATA) ? ng_qdzone : ng_qzone,
2990 	    ((flags & NG_WAITOK) ? M_WAITOK : M_NOWAIT) | M_ZERO);
2991 
2992 	if (item) {
2993 		item->el_flags = type;
2994 #ifdef	NETGRAPH_DEBUG
2995 		mtx_lock(&ngq_mtx);
2996 		TAILQ_INSERT_TAIL(&ng_itemlist, item, all);
2997 		allocated++;
2998 		mtx_unlock(&ngq_mtx);
2999 #endif
3000 	}
3001 
3002 	return (item);
3003 }
3004 
3005 /*
3006  * Release a queue entry
3007  */
3008 void
3009 ng_free_item(item_p item)
3010 {
3011 	/*
3012 	 * The item may hold resources on its own. We need to free
3013 	 * these before we can free the item. What they are depends upon
3014 	 * what kind of item it is. it is important that nodes zero
3015 	 * out pointers to resources that they remove from the item
3016 	 * or we release them again here.
3017 	 */
3018 	switch (item->el_flags & NGQF_TYPE) {
3019 	case NGQF_DATA:
3020 		/* If we have an mbuf still attached.. */
3021 		NG_FREE_M(_NGI_M(item));
3022 		break;
3023 	case NGQF_MESG:
3024 		_NGI_RETADDR(item) = 0;
3025 		NG_FREE_MSG(_NGI_MSG(item));
3026 		break;
3027 	case NGQF_FN:
3028 	case NGQF_FN2:
3029 		/* nothing to free really, */
3030 		_NGI_FN(item) = NULL;
3031 		_NGI_ARG1(item) = NULL;
3032 		_NGI_ARG2(item) = 0;
3033 		break;
3034 	}
3035 	/* If we still have a node or hook referenced... */
3036 	_NGI_CLR_NODE(item);
3037 	_NGI_CLR_HOOK(item);
3038 
3039 #ifdef	NETGRAPH_DEBUG
3040 	mtx_lock(&ngq_mtx);
3041 	TAILQ_REMOVE(&ng_itemlist, item, all);
3042 	allocated--;
3043 	mtx_unlock(&ngq_mtx);
3044 #endif
3045 	uma_zfree(((item->el_flags & NGQF_TYPE) == NGQF_DATA) ?
3046 	    ng_qdzone : ng_qzone, item);
3047 }
3048 
3049 /*
3050  * Change type of the queue entry.
3051  * Possibly reallocates it from another UMA zone.
3052  */
3053 static __inline item_p
3054 ng_realloc_item(item_p pitem, int type, int flags)
3055 {
3056 	item_p item;
3057 	int from, to;
3058 
3059 	KASSERT((pitem != NULL), ("%s: can't reallocate NULL", __func__));
3060 	KASSERT(((type & ~NGQF_TYPE) == 0),
3061 	    ("%s: incorrect item type: %d", __func__, type));
3062 
3063 	from = ((pitem->el_flags & NGQF_TYPE) == NGQF_DATA);
3064 	to = (type == NGQF_DATA);
3065 	if (from != to) {
3066 		/* If reallocation is required do it and copy item. */
3067 		if ((item = ng_alloc_item(type, flags)) == NULL) {
3068 			ng_free_item(pitem);
3069 			return (NULL);
3070 		}
3071 		*item = *pitem;
3072 		ng_free_item(pitem);
3073 	} else
3074 		item = pitem;
3075 	item->el_flags = (item->el_flags & ~NGQF_TYPE) | type;
3076 
3077 	return (item);
3078 }
3079 
3080 /************************************************************************
3081 			Module routines
3082 ************************************************************************/
3083 
3084 /*
3085  * Handle the loading/unloading of a netgraph node type module
3086  */
3087 int
3088 ng_mod_event(module_t mod, int event, void *data)
3089 {
3090 	struct ng_type *const type = data;
3091 	int error = 0;
3092 
3093 	switch (event) {
3094 	case MOD_LOAD:
3095 
3096 		/* Register new netgraph node type */
3097 		if ((error = ng_newtype(type)) != 0)
3098 			break;
3099 
3100 		/* Call type specific code */
3101 		if (type->mod_event != NULL)
3102 			if ((error = (*type->mod_event)(mod, event, data))) {
3103 				TYPELIST_WLOCK();
3104 				type->refs--;	/* undo it */
3105 				LIST_REMOVE(type, types);
3106 				TYPELIST_WUNLOCK();
3107 			}
3108 		break;
3109 
3110 	case MOD_UNLOAD:
3111 		if (type->refs > 1) {		/* make sure no nodes exist! */
3112 			error = EBUSY;
3113 		} else {
3114 			if (type->refs == 0) /* failed load, nothing to undo */
3115 				break;
3116 			if (type->mod_event != NULL) {	/* check with type */
3117 				error = (*type->mod_event)(mod, event, data);
3118 				if (error != 0)	/* type refuses.. */
3119 					break;
3120 			}
3121 			TYPELIST_WLOCK();
3122 			LIST_REMOVE(type, types);
3123 			TYPELIST_WUNLOCK();
3124 		}
3125 		break;
3126 
3127 	default:
3128 		if (type->mod_event != NULL)
3129 			error = (*type->mod_event)(mod, event, data);
3130 		else
3131 			error = EOPNOTSUPP;		/* XXX ? */
3132 		break;
3133 	}
3134 	return (error);
3135 }
3136 
3137 static void
3138 vnet_netgraph_init(const void *unused __unused)
3139 {
3140 
3141 	/* We start with small hashes, but they can grow. */
3142 	V_ng_ID_hash = hashinit(16, M_NETGRAPH_NODE, &V_ng_ID_hmask);
3143 	V_ng_name_hash = hashinit(16, M_NETGRAPH_NODE, &V_ng_name_hmask);
3144 }
3145 VNET_SYSINIT(vnet_netgraph_init, SI_SUB_NETGRAPH, SI_ORDER_FIRST,
3146     vnet_netgraph_init, NULL);
3147 
3148 #ifdef VIMAGE
3149 static void
3150 vnet_netgraph_uninit(const void *unused __unused)
3151 {
3152 	node_p node = NULL, last_killed = NULL;
3153 	int i;
3154 
3155 	do {
3156 		/* Find a node to kill */
3157 		IDHASH_RLOCK();
3158 		for (i = 0; i <= V_ng_ID_hmask; i++) {
3159 			LIST_FOREACH(node, &V_ng_ID_hash[i], nd_idnodes) {
3160 				if (node != &ng_deadnode) {
3161 					NG_NODE_REF(node);
3162 					break;
3163 				}
3164 			}
3165 			if (node != NULL)
3166 				break;
3167 		}
3168 		IDHASH_RUNLOCK();
3169 
3170 		/* Attempt to kill it only if it is a regular node */
3171 		if (node != NULL) {
3172 			if (node == last_killed) {
3173 				if (node->nd_flags & NGF_REALLY_DIE)
3174 					panic("ng node %s won't die",
3175 					    node->nd_name);
3176 				/* The node persisted itself.  Try again. */
3177 				node->nd_flags |= NGF_REALLY_DIE;
3178 			}
3179 			ng_rmnode(node, NULL, NULL, 0);
3180 			NG_NODE_UNREF(node);
3181 			last_killed = node;
3182 		}
3183 	} while (node != NULL);
3184 
3185 	hashdestroy(V_ng_name_hash, M_NETGRAPH_NODE, V_ng_name_hmask);
3186 	hashdestroy(V_ng_ID_hash, M_NETGRAPH_NODE, V_ng_ID_hmask);
3187 }
3188 VNET_SYSUNINIT(vnet_netgraph_uninit, SI_SUB_NETGRAPH, SI_ORDER_FIRST,
3189     vnet_netgraph_uninit, NULL);
3190 #endif /* VIMAGE */
3191 
3192 /*
3193  * Handle loading and unloading for this code.
3194  * The only thing we need to link into is the NETISR strucure.
3195  */
3196 static int
3197 ngb_mod_event(module_t mod, int event, void *data)
3198 {
3199 	struct proc *p;
3200 	struct thread *td;
3201 	int i, error = 0;
3202 
3203 	switch (event) {
3204 	case MOD_LOAD:
3205 		/* Initialize everything. */
3206 		NG_WORKLIST_LOCK_INIT();
3207 		rw_init(&ng_typelist_lock, "netgraph types");
3208 		rw_init(&ng_idhash_lock, "netgraph idhash");
3209 		rw_init(&ng_namehash_lock, "netgraph namehash");
3210 		rw_init(&ng_topo_lock, "netgraph topology mutex");
3211 #ifdef	NETGRAPH_DEBUG
3212 		mtx_init(&ng_nodelist_mtx, "netgraph nodelist mutex", NULL,
3213 		    MTX_DEF);
3214 		mtx_init(&ngq_mtx, "netgraph item list mutex", NULL,
3215 		    MTX_DEF);
3216 #endif
3217 		ng_qzone = uma_zcreate("NetGraph items", sizeof(struct ng_item),
3218 		    NULL, NULL, NULL, NULL, UMA_ALIGN_CACHE, 0);
3219 		uma_zone_set_max(ng_qzone, maxalloc);
3220 		ng_qdzone = uma_zcreate("NetGraph data items",
3221 		    sizeof(struct ng_item), NULL, NULL, NULL, NULL,
3222 		    UMA_ALIGN_CACHE, 0);
3223 		uma_zone_set_max(ng_qdzone, maxdata);
3224 		/* Autoconfigure number of threads. */
3225 		if (numthreads <= 0)
3226 			numthreads = mp_ncpus;
3227 		/* Create threads. */
3228     		p = NULL; /* start with no process */
3229 		for (i = 0; i < numthreads; i++) {
3230 			if (kproc_kthread_add(ngthread, NULL, &p, &td,
3231 			    RFHIGHPID, 0, "ng_queue", "ng_queue%d", i)) {
3232 				numthreads = i;
3233 				break;
3234 			}
3235 		}
3236 		break;
3237 	case MOD_UNLOAD:
3238 		/* You can't unload it because an interface may be using it. */
3239 		error = EBUSY;
3240 		break;
3241 	default:
3242 		error = EOPNOTSUPP;
3243 		break;
3244 	}
3245 	return (error);
3246 }
3247 
3248 static moduledata_t netgraph_mod = {
3249 	"netgraph",
3250 	ngb_mod_event,
3251 	(NULL)
3252 };
3253 DECLARE_MODULE(netgraph, netgraph_mod, SI_SUB_NETGRAPH, SI_ORDER_FIRST);
3254 SYSCTL_NODE(_net, OID_AUTO, graph, CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
3255     "netgraph Family");
3256 SYSCTL_INT(_net_graph, OID_AUTO, abi_version, CTLFLAG_RD, SYSCTL_NULL_INT_PTR, NG_ABI_VERSION,"");
3257 SYSCTL_INT(_net_graph, OID_AUTO, msg_version, CTLFLAG_RD, SYSCTL_NULL_INT_PTR, NG_VERSION, "");
3258 
3259 #ifdef	NETGRAPH_DEBUG
3260 void
3261 dumphook (hook_p hook, char *file, int line)
3262 {
3263 	printf("hook: name %s, %d refs, Last touched:\n",
3264 		_NG_HOOK_NAME(hook), hook->hk_refs);
3265 	printf("	Last active @ %s, line %d\n",
3266 		hook->lastfile, hook->lastline);
3267 	if (line) {
3268 		printf(" problem discovered at file %s, line %d\n", file, line);
3269 #ifdef KDB
3270 		kdb_backtrace();
3271 #endif
3272 	}
3273 }
3274 
3275 void
3276 dumpnode(node_p node, char *file, int line)
3277 {
3278 	printf("node: ID [%x]: type '%s', %d hooks, flags 0x%x, %d refs, %s:\n",
3279 		_NG_NODE_ID(node), node->nd_type->name,
3280 		node->nd_numhooks, node->nd_flags,
3281 		node->nd_refs, node->nd_name);
3282 	printf("	Last active @ %s, line %d\n",
3283 		node->lastfile, node->lastline);
3284 	if (line) {
3285 		printf(" problem discovered at file %s, line %d\n", file, line);
3286 #ifdef KDB
3287 		kdb_backtrace();
3288 #endif
3289 	}
3290 }
3291 
3292 void
3293 dumpitem(item_p item, char *file, int line)
3294 {
3295 	printf(" ACTIVE item, last used at %s, line %d",
3296 		item->lastfile, item->lastline);
3297 	switch(item->el_flags & NGQF_TYPE) {
3298 	case NGQF_DATA:
3299 		printf(" - [data]\n");
3300 		break;
3301 	case NGQF_MESG:
3302 		printf(" - retaddr[%d]:\n", _NGI_RETADDR(item));
3303 		break;
3304 	case NGQF_FN:
3305 		printf(" - fn@%p (%p, %p, %p, %d (%x))\n",
3306 			_NGI_FN(item),
3307 			_NGI_NODE(item),
3308 			_NGI_HOOK(item),
3309 			item->body.fn.fn_arg1,
3310 			item->body.fn.fn_arg2,
3311 			item->body.fn.fn_arg2);
3312 		break;
3313 	case NGQF_FN2:
3314 		printf(" - fn2@%p (%p, %p, %p, %d (%x))\n",
3315 			_NGI_FN2(item),
3316 			_NGI_NODE(item),
3317 			_NGI_HOOK(item),
3318 			item->body.fn.fn_arg1,
3319 			item->body.fn.fn_arg2,
3320 			item->body.fn.fn_arg2);
3321 		break;
3322 	}
3323 	if (line) {
3324 		printf(" problem discovered at file %s, line %d\n", file, line);
3325 		if (_NGI_NODE(item)) {
3326 			printf("node %p ([%x])\n",
3327 				_NGI_NODE(item), ng_node2ID(_NGI_NODE(item)));
3328 		}
3329 	}
3330 }
3331 
3332 static void
3333 ng_dumpitems(void)
3334 {
3335 	item_p item;
3336 	int i = 1;
3337 	TAILQ_FOREACH(item, &ng_itemlist, all) {
3338 		printf("[%d] ", i++);
3339 		dumpitem(item, NULL, 0);
3340 	}
3341 }
3342 
3343 static void
3344 ng_dumpnodes(void)
3345 {
3346 	node_p node;
3347 	int i = 1;
3348 	mtx_lock(&ng_nodelist_mtx);
3349 	SLIST_FOREACH(node, &ng_allnodes, nd_all) {
3350 		printf("[%d] ", i++);
3351 		dumpnode(node, NULL, 0);
3352 	}
3353 	mtx_unlock(&ng_nodelist_mtx);
3354 }
3355 
3356 static void
3357 ng_dumphooks(void)
3358 {
3359 	hook_p hook;
3360 	int i = 1;
3361 	mtx_lock(&ng_nodelist_mtx);
3362 	SLIST_FOREACH(hook, &ng_allhooks, hk_all) {
3363 		printf("[%d] ", i++);
3364 		dumphook(hook, NULL, 0);
3365 	}
3366 	mtx_unlock(&ng_nodelist_mtx);
3367 }
3368 
3369 static int
3370 sysctl_debug_ng_dump_items(SYSCTL_HANDLER_ARGS)
3371 {
3372 	int error;
3373 	int val;
3374 	int i;
3375 
3376 	val = allocated;
3377 	i = 1;
3378 	error = sysctl_handle_int(oidp, &val, 0, req);
3379 	if (error != 0 || req->newptr == NULL)
3380 		return (error);
3381 	if (val == 42) {
3382 		ng_dumpitems();
3383 		ng_dumpnodes();
3384 		ng_dumphooks();
3385 	}
3386 	return (0);
3387 }
3388 
3389 SYSCTL_PROC(_debug, OID_AUTO, ng_dump_items,
3390     CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_NEEDGIANT, 0, sizeof(int),
3391     sysctl_debug_ng_dump_items, "I",
3392     "Number of allocated items");
3393 #endif	/* NETGRAPH_DEBUG */
3394 
3395 /***********************************************************************
3396 * Worklist routines
3397 **********************************************************************/
3398 /*
3399  * Pick a node off the list of nodes with work,
3400  * try get an item to process off it. Remove the node from the list.
3401  */
3402 static void
3403 ngthread(void *arg)
3404 {
3405 	for (;;) {
3406 		struct epoch_tracker et;
3407 		node_p  node;
3408 
3409 		/* Get node from the worklist. */
3410 		NG_WORKLIST_LOCK();
3411 		while ((node = STAILQ_FIRST(&ng_worklist)) == NULL)
3412 			NG_WORKLIST_SLEEP();
3413 		STAILQ_REMOVE_HEAD(&ng_worklist, nd_input_queue.q_work);
3414 		NG_WORKLIST_UNLOCK();
3415 		CURVNET_SET(node->nd_vnet);
3416 		CTR3(KTR_NET, "%20s: node [%x] (%p) taken off worklist",
3417 		    __func__, node->nd_ID, node);
3418 		/*
3419 		 * We have the node. We also take over the reference
3420 		 * that the list had on it.
3421 		 * Now process as much as you can, until it won't
3422 		 * let you have another item off the queue.
3423 		 * All this time, keep the reference
3424 		 * that lets us be sure that the node still exists.
3425 		 * Let the reference go at the last minute.
3426 		 */
3427 		NET_EPOCH_ENTER(et);
3428 		for (;;) {
3429 			item_p item;
3430 			int rw;
3431 
3432 			NG_QUEUE_LOCK(&node->nd_input_queue);
3433 			item = ng_dequeue(node, &rw);
3434 			if (item == NULL) {
3435 				node->nd_input_queue.q_flags2 &= ~NGQ2_WORKQ;
3436 				NG_QUEUE_UNLOCK(&node->nd_input_queue);
3437 				break; /* go look for another node */
3438 			} else {
3439 				NG_QUEUE_UNLOCK(&node->nd_input_queue);
3440 				NGI_GET_NODE(item, node); /* zaps stored node */
3441 				ng_apply_item(node, item, rw);
3442 				NG_NODE_UNREF(node);
3443 			}
3444 		}
3445 		NET_EPOCH_EXIT(et);
3446 		NG_NODE_UNREF(node);
3447 		CURVNET_RESTORE();
3448 	}
3449 }
3450 
3451 /*
3452  * XXX
3453  * It's posible that a debugging NG_NODE_REF may need
3454  * to be outside the mutex zone
3455  */
3456 static void
3457 ng_worklist_add(node_p node)
3458 {
3459 
3460 	mtx_assert(&node->nd_input_queue.q_mtx, MA_OWNED);
3461 
3462 	if ((node->nd_input_queue.q_flags2 & NGQ2_WORKQ) == 0) {
3463 		/*
3464 		 * If we are not already on the work queue,
3465 		 * then put us on.
3466 		 */
3467 		node->nd_input_queue.q_flags2 |= NGQ2_WORKQ;
3468 		NG_NODE_REF(node); /* XXX safe in mutex? */
3469 		NG_WORKLIST_LOCK();
3470 		STAILQ_INSERT_TAIL(&ng_worklist, node, nd_input_queue.q_work);
3471 		NG_WORKLIST_UNLOCK();
3472 		CTR3(KTR_NET, "%20s: node [%x] (%p) put on worklist", __func__,
3473 		    node->nd_ID, node);
3474 		NG_WORKLIST_WAKEUP();
3475 	} else {
3476 		CTR3(KTR_NET, "%20s: node [%x] (%p) already on worklist",
3477 		    __func__, node->nd_ID, node);
3478 	}
3479 }
3480 
3481 /***********************************************************************
3482 * Externally useable functions to set up a queue item ready for sending
3483 ***********************************************************************/
3484 
3485 #ifdef	NETGRAPH_DEBUG
3486 #define	ITEM_DEBUG_CHECKS						\
3487 	do {								\
3488 		if (NGI_NODE(item) ) {					\
3489 			printf("item already has node");		\
3490 			kdb_enter(KDB_WHY_NETGRAPH, "has node");	\
3491 			NGI_CLR_NODE(item);				\
3492 		}							\
3493 		if (NGI_HOOK(item) ) {					\
3494 			printf("item already has hook");		\
3495 			kdb_enter(KDB_WHY_NETGRAPH, "has hook");	\
3496 			NGI_CLR_HOOK(item);				\
3497 		}							\
3498 	} while (0)
3499 #else
3500 #define ITEM_DEBUG_CHECKS
3501 #endif
3502 
3503 /*
3504  * Put mbuf into the item.
3505  * Hook and node references will be removed when the item is dequeued.
3506  * (or equivalent)
3507  * (XXX) Unsafe because no reference held by peer on remote node.
3508  * remote node might go away in this timescale.
3509  * We know the hooks can't go away because that would require getting
3510  * a writer item on both nodes and we must have at least a  reader
3511  * here to be able to do this.
3512  * Note that the hook loaded is the REMOTE hook.
3513  *
3514  * This is possibly in the critical path for new data.
3515  */
3516 item_p
3517 ng_package_data(struct mbuf *m, int flags)
3518 {
3519 	item_p item;
3520 
3521 	if ((item = ng_alloc_item(NGQF_DATA, flags)) == NULL) {
3522 		NG_FREE_M(m);
3523 		return (NULL);
3524 	}
3525 	ITEM_DEBUG_CHECKS;
3526 	item->el_flags |= NGQF_READER;
3527 	NGI_M(item) = m;
3528 	return (item);
3529 }
3530 
3531 /*
3532  * Allocate a queue item and put items into it..
3533  * Evaluate the address as this will be needed to queue it and
3534  * to work out what some of the fields should be.
3535  * Hook and node references will be removed when the item is dequeued.
3536  * (or equivalent)
3537  */
3538 item_p
3539 ng_package_msg(struct ng_mesg *msg, int flags)
3540 {
3541 	item_p item;
3542 
3543 	if ((item = ng_alloc_item(NGQF_MESG, flags)) == NULL) {
3544 		NG_FREE_MSG(msg);
3545 		return (NULL);
3546 	}
3547 	ITEM_DEBUG_CHECKS;
3548 	/* Messages items count as writers unless explicitly exempted. */
3549 	if (msg->header.cmd & NGM_READONLY)
3550 		item->el_flags |= NGQF_READER;
3551 	else
3552 		item->el_flags |= NGQF_WRITER;
3553 	/*
3554 	 * Set the current lasthook into the queue item
3555 	 */
3556 	NGI_MSG(item) = msg;
3557 	NGI_RETADDR(item) = 0;
3558 	return (item);
3559 }
3560 
3561 #define SET_RETADDR(item, here, retaddr)				\
3562 	do {	/* Data or fn items don't have retaddrs */		\
3563 		if ((item->el_flags & NGQF_TYPE) == NGQF_MESG) {	\
3564 			if (retaddr) {					\
3565 				NGI_RETADDR(item) = retaddr;		\
3566 			} else {					\
3567 				/*					\
3568 				 * The old return address should be ok.	\
3569 				 * If there isn't one, use the address	\
3570 				 * here.				\
3571 				 */					\
3572 				if (NGI_RETADDR(item) == 0) {		\
3573 					NGI_RETADDR(item)		\
3574 						= ng_node2ID(here);	\
3575 				}					\
3576 			}						\
3577 		}							\
3578 	} while (0)
3579 
3580 int
3581 ng_address_hook(node_p here, item_p item, hook_p hook, ng_ID_t retaddr)
3582 {
3583 	hook_p peer;
3584 	node_p peernode;
3585 	ITEM_DEBUG_CHECKS;
3586 	/*
3587 	 * Quick sanity check..
3588 	 * Since a hook holds a reference on its node, once we know
3589 	 * that the peer is still connected (even if invalid,) we know
3590 	 * that the peer node is present, though maybe invalid.
3591 	 */
3592 	TOPOLOGY_RLOCK();
3593 	if ((hook == NULL) || NG_HOOK_NOT_VALID(hook) ||
3594 	    NG_HOOK_NOT_VALID(peer = NG_HOOK_PEER(hook)) ||
3595 	    NG_NODE_NOT_VALID(peernode = NG_PEER_NODE(hook))) {
3596 		NG_FREE_ITEM(item);
3597 		TRAP_ERROR();
3598 		TOPOLOGY_RUNLOCK();
3599 		return (ENETDOWN);
3600 	}
3601 
3602 	/*
3603 	 * Transfer our interest to the other (peer) end.
3604 	 */
3605 	NG_HOOK_REF(peer);
3606 	NG_NODE_REF(peernode);
3607 	NGI_SET_HOOK(item, peer);
3608 	NGI_SET_NODE(item, peernode);
3609 	SET_RETADDR(item, here, retaddr);
3610 
3611 	TOPOLOGY_RUNLOCK();
3612 
3613 	return (0);
3614 }
3615 
3616 int
3617 ng_address_path(node_p here, item_p item, const char *address, ng_ID_t retaddr)
3618 {
3619 	node_p	dest = NULL;
3620 	hook_p	hook = NULL;
3621 	int	error;
3622 
3623 	ITEM_DEBUG_CHECKS;
3624 	/*
3625 	 * Note that ng_path2noderef increments the reference count
3626 	 * on the node for us if it finds one. So we don't have to.
3627 	 */
3628 	error = ng_path2noderef(here, address, &dest, &hook);
3629 	if (error) {
3630 		NG_FREE_ITEM(item);
3631 		return (error);
3632 	}
3633 	NGI_SET_NODE(item, dest);
3634 	if (hook)
3635 		NGI_SET_HOOK(item, hook);
3636 
3637 	SET_RETADDR(item, here, retaddr);
3638 	return (0);
3639 }
3640 
3641 int
3642 ng_address_ID(node_p here, item_p item, ng_ID_t ID, ng_ID_t retaddr)
3643 {
3644 	node_p dest;
3645 
3646 	ITEM_DEBUG_CHECKS;
3647 	/*
3648 	 * Find the target node.
3649 	 */
3650 	dest = ng_ID2noderef(ID); /* GETS REFERENCE! */
3651 	if (dest == NULL) {
3652 		NG_FREE_ITEM(item);
3653 		TRAP_ERROR();
3654 		return(EINVAL);
3655 	}
3656 	/* Fill out the contents */
3657 	NGI_SET_NODE(item, dest);
3658 	NGI_CLR_HOOK(item);
3659 	SET_RETADDR(item, here, retaddr);
3660 	return (0);
3661 }
3662 
3663 /*
3664  * special case to send a message to self (e.g. destroy node)
3665  * Possibly indicate an arrival hook too.
3666  * Useful for removing that hook :-)
3667  */
3668 item_p
3669 ng_package_msg_self(node_p here, hook_p hook, struct ng_mesg *msg)
3670 {
3671 	item_p item;
3672 
3673 	/*
3674 	 * Find the target node.
3675 	 * If there is a HOOK argument, then use that in preference
3676 	 * to the address.
3677 	 */
3678 	if ((item = ng_alloc_item(NGQF_MESG, NG_NOFLAGS)) == NULL) {
3679 		NG_FREE_MSG(msg);
3680 		return (NULL);
3681 	}
3682 
3683 	/* Fill out the contents */
3684 	item->el_flags |= NGQF_WRITER;
3685 	NG_NODE_REF(here);
3686 	NGI_SET_NODE(item, here);
3687 	if (hook) {
3688 		NG_HOOK_REF(hook);
3689 		NGI_SET_HOOK(item, hook);
3690 	}
3691 	NGI_MSG(item) = msg;
3692 	NGI_RETADDR(item) = ng_node2ID(here);
3693 	return (item);
3694 }
3695 
3696 /*
3697  * Send ng_item_fn function call to the specified node.
3698  */
3699 
3700 int
3701 ng_send_fn(node_p node, hook_p hook, ng_item_fn *fn, void * arg1, int arg2)
3702 {
3703 
3704 	return ng_send_fn1(node, hook, fn, arg1, arg2, NG_NOFLAGS);
3705 }
3706 
3707 int
3708 ng_send_fn1(node_p node, hook_p hook, ng_item_fn *fn, void * arg1, int arg2,
3709 	int flags)
3710 {
3711 	item_p item;
3712 
3713 	if ((item = ng_alloc_item(NGQF_FN, flags)) == NULL) {
3714 		return (ENOMEM);
3715 	}
3716 	item->el_flags |= NGQF_WRITER;
3717 	NG_NODE_REF(node); /* and one for the item */
3718 	NGI_SET_NODE(item, node);
3719 	if (hook) {
3720 		NG_HOOK_REF(hook);
3721 		NGI_SET_HOOK(item, hook);
3722 	}
3723 	NGI_FN(item) = fn;
3724 	NGI_ARG1(item) = arg1;
3725 	NGI_ARG2(item) = arg2;
3726 	return(ng_snd_item(item, flags));
3727 }
3728 
3729 /*
3730  * Send ng_item_fn2 function call to the specified node.
3731  *
3732  * If an optional pitem parameter is supplied, its apply
3733  * callback will be copied to the new item. If also NG_REUSE_ITEM
3734  * flag is set, no new item will be allocated, but pitem will
3735  * be used.
3736  */
3737 int
3738 ng_send_fn2(node_p node, hook_p hook, item_p pitem, ng_item_fn2 *fn, void *arg1,
3739 	int arg2, int flags)
3740 {
3741 	item_p item;
3742 
3743 	KASSERT((pitem != NULL || (flags & NG_REUSE_ITEM) == 0),
3744 	    ("%s: NG_REUSE_ITEM but no pitem", __func__));
3745 
3746 	/*
3747 	 * Allocate a new item if no supplied or
3748 	 * if we can't use supplied one.
3749 	 */
3750 	if (pitem == NULL || (flags & NG_REUSE_ITEM) == 0) {
3751 		if ((item = ng_alloc_item(NGQF_FN2, flags)) == NULL)
3752 			return (ENOMEM);
3753 		if (pitem != NULL)
3754 			item->apply = pitem->apply;
3755 	} else {
3756 		if ((item = ng_realloc_item(pitem, NGQF_FN2, flags)) == NULL)
3757 			return (ENOMEM);
3758 	}
3759 
3760 	item->el_flags = (item->el_flags & ~NGQF_RW) | NGQF_WRITER;
3761 	NG_NODE_REF(node); /* and one for the item */
3762 	NGI_SET_NODE(item, node);
3763 	if (hook) {
3764 		NG_HOOK_REF(hook);
3765 		NGI_SET_HOOK(item, hook);
3766 	}
3767 	NGI_FN2(item) = fn;
3768 	NGI_ARG1(item) = arg1;
3769 	NGI_ARG2(item) = arg2;
3770 	return(ng_snd_item(item, flags));
3771 }
3772 
3773 /*
3774  * Official timeout routines for Netgraph nodes.
3775  */
3776 static void
3777 ng_callout_trampoline(void *arg)
3778 {
3779 	struct epoch_tracker et;
3780 	item_p item = arg;
3781 
3782 	NET_EPOCH_ENTER(et);
3783 	CURVNET_SET(NGI_NODE(item)->nd_vnet);
3784 	ng_snd_item(item, 0);
3785 	CURVNET_RESTORE();
3786 	NET_EPOCH_EXIT(et);
3787 }
3788 
3789 int
3790 ng_callout(struct callout *c, node_p node, hook_p hook, int ticks,
3791     ng_item_fn *fn, void * arg1, int arg2)
3792 {
3793 	item_p item, oitem;
3794 
3795 	if ((item = ng_alloc_item(NGQF_FN, NG_NOFLAGS)) == NULL)
3796 		return (ENOMEM);
3797 
3798 	item->el_flags |= NGQF_WRITER;
3799 	NG_NODE_REF(node);		/* and one for the item */
3800 	NGI_SET_NODE(item, node);
3801 	if (hook) {
3802 		NG_HOOK_REF(hook);
3803 		NGI_SET_HOOK(item, hook);
3804 	}
3805 	NGI_FN(item) = fn;
3806 	NGI_ARG1(item) = arg1;
3807 	NGI_ARG2(item) = arg2;
3808 	oitem = c->c_arg;
3809 	if (callout_reset(c, ticks, &ng_callout_trampoline, item) == 1 &&
3810 	    oitem != NULL)
3811 		NG_FREE_ITEM(oitem);
3812 	return (0);
3813 }
3814 
3815 /* A special modified version of callout_stop() */
3816 int
3817 ng_uncallout(struct callout *c, node_p node)
3818 {
3819 	item_p item;
3820 	int rval;
3821 
3822 	KASSERT(c != NULL, ("ng_uncallout: NULL callout"));
3823 	KASSERT(node != NULL, ("ng_uncallout: NULL node"));
3824 
3825 	rval = callout_stop(c);
3826 	item = c->c_arg;
3827 	/* Do an extra check */
3828 	if ((rval > 0) && (c->c_func == &ng_callout_trampoline) &&
3829 	    (item != NULL) && (NGI_NODE(item) == node)) {
3830 		/*
3831 		 * We successfully removed it from the queue before it ran
3832 		 * So now we need to unreference everything that was
3833 		 * given extra references. (NG_FREE_ITEM does this).
3834 		 */
3835 		NG_FREE_ITEM(item);
3836 	}
3837 	c->c_arg = NULL;
3838 
3839 	/*
3840 	 * Callers only want to know if the callout was cancelled and
3841 	 * not draining or stopped.
3842 	 */
3843 	return (rval > 0);
3844 }
3845 
3846 /*
3847  * Set the address, if none given, give the node here.
3848  */
3849 void
3850 ng_replace_retaddr(node_p here, item_p item, ng_ID_t retaddr)
3851 {
3852 	if (retaddr) {
3853 		NGI_RETADDR(item) = retaddr;
3854 	} else {
3855 		/*
3856 		 * The old return address should be ok.
3857 		 * If there isn't one, use the address here.
3858 		 */
3859 		NGI_RETADDR(item) = ng_node2ID(here);
3860 	}
3861 }
3862