xref: /freebsd/sys/netgraph/ng_base.c (revision 911f0260390e18cf85f3dbf2c719b593efdc1e3c)
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 <machine/stack.h>
70 
71 #include <net/netisr.h>
72 #include <net/vnet.h>
73 
74 #include <netgraph/ng_message.h>
75 #include <netgraph/netgraph.h>
76 #include <netgraph/ng_parse.h>
77 
78 MODULE_VERSION(netgraph, NG_ABI_VERSION);
79 
80 /* Mutex to protect topology events. */
81 static struct rwlock	ng_topo_lock;
82 #define	TOPOLOGY_RLOCK()	rw_rlock(&ng_topo_lock)
83 #define	TOPOLOGY_RUNLOCK()	rw_runlock(&ng_topo_lock)
84 #define	TOPOLOGY_WLOCK()	rw_wlock(&ng_topo_lock)
85 #define	TOPOLOGY_WUNLOCK()	rw_wunlock(&ng_topo_lock)
86 #define	TOPOLOGY_NOTOWNED()	rw_assert(&ng_topo_lock, RA_UNLOCKED)
87 
88 #ifdef	NETGRAPH_DEBUG
89 static struct mtx	ng_nodelist_mtx; /* protects global node/hook lists */
90 static struct mtx	ngq_mtx;	/* protects the queue item list */
91 
92 static SLIST_HEAD(, ng_node) ng_allnodes;
93 static LIST_HEAD(, ng_node) ng_freenodes; /* in debug, we never free() them */
94 static SLIST_HEAD(, ng_hook) ng_allhooks;
95 static LIST_HEAD(, ng_hook) ng_freehooks; /* in debug, we never free() them */
96 
97 static void ng_dumpitems(void);
98 static void ng_dumpnodes(void);
99 static void ng_dumphooks(void);
100 
101 #endif	/* NETGRAPH_DEBUG */
102 /*
103  * DEAD versions of the structures.
104  * In order to avoid races, it is sometimes necessary to point
105  * at SOMETHING even though theoretically, the current entity is
106  * INVALID. Use these to avoid these races.
107  */
108 struct ng_type ng_deadtype = {
109 	NG_ABI_VERSION,
110 	"dead",
111 	NULL,	/* modevent */
112 	NULL,	/* constructor */
113 	NULL,	/* rcvmsg */
114 	NULL,	/* shutdown */
115 	NULL,	/* newhook */
116 	NULL,	/* findhook */
117 	NULL,	/* connect */
118 	NULL,	/* rcvdata */
119 	NULL,	/* disconnect */
120 	NULL, 	/* cmdlist */
121 };
122 
123 struct ng_node ng_deadnode = {
124 	"dead",
125 	&ng_deadtype,
126 	NGF_INVALID,
127 	0,	/* numhooks */
128 	NULL,	/* private */
129 	0,	/* ID */
130 	LIST_HEAD_INITIALIZER(ng_deadnode.nd_hooks),
131 	{},	/* all_nodes list entry */
132 	{},	/* id hashtable list entry */
133 	{	0,
134 		0,
135 		{}, /* should never use! (should hang) */
136 		{}, /* workqueue entry */
137 		STAILQ_HEAD_INITIALIZER(ng_deadnode.nd_input_queue.queue),
138 	},
139 	1,	/* refs */
140 	NULL,	/* vnet */
141 #ifdef	NETGRAPH_DEBUG
142 	ND_MAGIC,
143 	__FILE__,
144 	__LINE__,
145 	{NULL}
146 #endif	/* NETGRAPH_DEBUG */
147 };
148 
149 struct ng_hook ng_deadhook = {
150 	"dead",
151 	NULL,		/* private */
152 	HK_INVALID | HK_DEAD,
153 	0,		/* undefined data link type */
154 	&ng_deadhook,	/* Peer is self */
155 	&ng_deadnode,	/* attached to deadnode */
156 	{},		/* hooks list */
157 	NULL,		/* override rcvmsg() */
158 	NULL,		/* override rcvdata() */
159 	1,		/* refs always >= 1 */
160 #ifdef	NETGRAPH_DEBUG
161 	HK_MAGIC,
162 	__FILE__,
163 	__LINE__,
164 	{NULL}
165 #endif	/* NETGRAPH_DEBUG */
166 };
167 
168 /*
169  * END DEAD STRUCTURES
170  */
171 /* List nodes with unallocated work */
172 static STAILQ_HEAD(, ng_node) ng_worklist = STAILQ_HEAD_INITIALIZER(ng_worklist);
173 static struct mtx	ng_worklist_mtx;   /* MUST LOCK NODE FIRST */
174 
175 /* List of installed types */
176 static LIST_HEAD(, ng_type) ng_typelist;
177 static struct rwlock	ng_typelist_lock;
178 #define	TYPELIST_RLOCK()	rw_rlock(&ng_typelist_lock)
179 #define	TYPELIST_RUNLOCK()	rw_runlock(&ng_typelist_lock)
180 #define	TYPELIST_WLOCK()	rw_wlock(&ng_typelist_lock)
181 #define	TYPELIST_WUNLOCK()	rw_wunlock(&ng_typelist_lock)
182 
183 /* Hash related definitions. */
184 LIST_HEAD(nodehash, ng_node);
185 VNET_DEFINE_STATIC(struct nodehash *, ng_ID_hash);
186 VNET_DEFINE_STATIC(u_long, ng_ID_hmask);
187 VNET_DEFINE_STATIC(u_long, ng_nodes);
188 VNET_DEFINE_STATIC(struct nodehash *, ng_name_hash);
189 VNET_DEFINE_STATIC(u_long, ng_name_hmask);
190 VNET_DEFINE_STATIC(u_long, ng_named_nodes);
191 #define	V_ng_ID_hash		VNET(ng_ID_hash)
192 #define	V_ng_ID_hmask		VNET(ng_ID_hmask)
193 #define	V_ng_nodes		VNET(ng_nodes)
194 #define	V_ng_name_hash		VNET(ng_name_hash)
195 #define	V_ng_name_hmask		VNET(ng_name_hmask)
196 #define	V_ng_named_nodes	VNET(ng_named_nodes)
197 
198 static struct rwlock	ng_idhash_lock;
199 #define	IDHASH_RLOCK()		rw_rlock(&ng_idhash_lock)
200 #define	IDHASH_RUNLOCK()	rw_runlock(&ng_idhash_lock)
201 #define	IDHASH_WLOCK()		rw_wlock(&ng_idhash_lock)
202 #define	IDHASH_WUNLOCK()	rw_wunlock(&ng_idhash_lock)
203 
204 /* Method to find a node.. used twice so do it here */
205 #define NG_IDHASH_FN(ID) ((ID) % (V_ng_ID_hmask + 1))
206 #define NG_IDHASH_FIND(ID, node)					\
207 	do { 								\
208 		rw_assert(&ng_idhash_lock, RA_LOCKED);			\
209 		LIST_FOREACH(node, &V_ng_ID_hash[NG_IDHASH_FN(ID)],	\
210 						nd_idnodes) {		\
211 			if (NG_NODE_IS_VALID(node)			\
212 			&& (NG_NODE_ID(node) == ID)) {			\
213 				break;					\
214 			}						\
215 		}							\
216 	} while (0)
217 
218 static struct rwlock	ng_namehash_lock;
219 #define	NAMEHASH_RLOCK()	rw_rlock(&ng_namehash_lock)
220 #define	NAMEHASH_RUNLOCK()	rw_runlock(&ng_namehash_lock)
221 #define	NAMEHASH_WLOCK()	rw_wlock(&ng_namehash_lock)
222 #define	NAMEHASH_WUNLOCK()	rw_wunlock(&ng_namehash_lock)
223 
224 /* Internal functions */
225 static int	ng_add_hook(node_p node, const char *name, hook_p * hookp);
226 static int	ng_generic_msg(node_p here, item_p item, hook_p lasthook);
227 static ng_ID_t	ng_decodeidname(const char *name);
228 static int	ngb_mod_event(module_t mod, int event, void *data);
229 static void	ng_worklist_add(node_p node);
230 static void	ngthread(void *);
231 static int	ng_apply_item(node_p node, item_p item, int rw);
232 static void	ng_flush_input_queue(node_p node);
233 static node_p	ng_ID2noderef(ng_ID_t ID);
234 static int	ng_con_nodes(item_p item, node_p node, const char *name,
235 		    node_p node2, const char *name2);
236 static int	ng_con_part2(node_p node, item_p item, hook_p hook);
237 static int	ng_con_part3(node_p node, item_p item, hook_p hook);
238 static int	ng_mkpeer(node_p node, const char *name, const char *name2,
239 		    char *type);
240 static void	ng_name_rehash(void);
241 static void	ng_ID_rehash(void);
242 
243 /* Imported, these used to be externally visible, some may go back. */
244 void	ng_destroy_hook(hook_p hook);
245 int	ng_path2noderef(node_p here, const char *path,
246 	node_p *dest, hook_p *lasthook);
247 int	ng_make_node(const char *type, node_p *nodepp);
248 int	ng_path_parse(char *addr, char **node, char **path, char **hook);
249 void	ng_rmnode(node_p node, hook_p dummy1, void *dummy2, int dummy3);
250 void	ng_unname(node_p node);
251 
252 /* Our own netgraph malloc type */
253 MALLOC_DEFINE(M_NETGRAPH, "netgraph", "netgraph structures and ctrl messages");
254 MALLOC_DEFINE(M_NETGRAPH_MSG, "netgraph_msg", "netgraph name storage");
255 static MALLOC_DEFINE(M_NETGRAPH_HOOK, "netgraph_hook",
256     "netgraph hook structures");
257 static MALLOC_DEFINE(M_NETGRAPH_NODE, "netgraph_node",
258     "netgraph node structures");
259 static MALLOC_DEFINE(M_NETGRAPH_ITEM, "netgraph_item",
260     "netgraph item structures");
261 
262 /* Should not be visible outside this file */
263 
264 #define _NG_ALLOC_HOOK(hook) \
265 	hook = malloc(sizeof(*hook), M_NETGRAPH_HOOK, M_NOWAIT | M_ZERO)
266 #define _NG_ALLOC_NODE(node) \
267 	node = malloc(sizeof(*node), M_NETGRAPH_NODE, M_NOWAIT | M_ZERO)
268 
269 #define	NG_QUEUE_LOCK_INIT(n)			\
270 	mtx_init(&(n)->q_mtx, "ng_node", NULL, MTX_DEF)
271 #define	NG_QUEUE_LOCK(n)			\
272 	mtx_lock(&(n)->q_mtx)
273 #define	NG_QUEUE_UNLOCK(n)			\
274 	mtx_unlock(&(n)->q_mtx)
275 #define	NG_WORKLIST_LOCK_INIT()			\
276 	mtx_init(&ng_worklist_mtx, "ng_worklist", NULL, MTX_DEF)
277 #define	NG_WORKLIST_LOCK()			\
278 	mtx_lock(&ng_worklist_mtx)
279 #define	NG_WORKLIST_UNLOCK()			\
280 	mtx_unlock(&ng_worklist_mtx)
281 #define	NG_WORKLIST_SLEEP()			\
282 	mtx_sleep(&ng_worklist, &ng_worklist_mtx, PI_NET, "sleep", 0)
283 #define	NG_WORKLIST_WAKEUP()			\
284 	wakeup_one(&ng_worklist)
285 
286 #ifdef NETGRAPH_DEBUG /*----------------------------------------------*/
287 /*
288  * In debug mode:
289  * In an attempt to help track reference count screwups
290  * we do not free objects back to the malloc system, but keep them
291  * in a local cache where we can examine them and keep information safely
292  * after they have been freed.
293  * We use this scheme for nodes and hooks, and to some extent for items.
294  */
295 static __inline hook_p
296 ng_alloc_hook(void)
297 {
298 	hook_p hook;
299 	SLIST_ENTRY(ng_hook) temp;
300 	mtx_lock(&ng_nodelist_mtx);
301 	hook = LIST_FIRST(&ng_freehooks);
302 	if (hook) {
303 		LIST_REMOVE(hook, hk_hooks);
304 		bcopy(&hook->hk_all, &temp, sizeof(temp));
305 		bzero(hook, sizeof(struct ng_hook));
306 		bcopy(&temp, &hook->hk_all, sizeof(temp));
307 		mtx_unlock(&ng_nodelist_mtx);
308 		hook->hk_magic = HK_MAGIC;
309 	} else {
310 		mtx_unlock(&ng_nodelist_mtx);
311 		_NG_ALLOC_HOOK(hook);
312 		if (hook) {
313 			hook->hk_magic = HK_MAGIC;
314 			mtx_lock(&ng_nodelist_mtx);
315 			SLIST_INSERT_HEAD(&ng_allhooks, hook, hk_all);
316 			mtx_unlock(&ng_nodelist_mtx);
317 		}
318 	}
319 	return (hook);
320 }
321 
322 static __inline node_p
323 ng_alloc_node(void)
324 {
325 	node_p node;
326 	SLIST_ENTRY(ng_node) temp;
327 	mtx_lock(&ng_nodelist_mtx);
328 	node = LIST_FIRST(&ng_freenodes);
329 	if (node) {
330 		LIST_REMOVE(node, nd_nodes);
331 		bcopy(&node->nd_all, &temp, sizeof(temp));
332 		bzero(node, sizeof(struct ng_node));
333 		bcopy(&temp, &node->nd_all, sizeof(temp));
334 		mtx_unlock(&ng_nodelist_mtx);
335 		node->nd_magic = ND_MAGIC;
336 	} else {
337 		mtx_unlock(&ng_nodelist_mtx);
338 		_NG_ALLOC_NODE(node);
339 		if (node) {
340 			node->nd_magic = ND_MAGIC;
341 			mtx_lock(&ng_nodelist_mtx);
342 			SLIST_INSERT_HEAD(&ng_allnodes, node, nd_all);
343 			mtx_unlock(&ng_nodelist_mtx);
344 		}
345 	}
346 	return (node);
347 }
348 
349 #define NG_ALLOC_HOOK(hook) do { (hook) = ng_alloc_hook(); } while (0)
350 #define NG_ALLOC_NODE(node) do { (node) = ng_alloc_node(); } while (0)
351 
352 #define NG_FREE_HOOK(hook)						\
353 	do {								\
354 		mtx_lock(&ng_nodelist_mtx);				\
355 		LIST_INSERT_HEAD(&ng_freehooks, hook, hk_hooks);	\
356 		hook->hk_magic = 0;					\
357 		mtx_unlock(&ng_nodelist_mtx);				\
358 	} while (0)
359 
360 #define NG_FREE_NODE(node)						\
361 	do {								\
362 		mtx_lock(&ng_nodelist_mtx);				\
363 		LIST_INSERT_HEAD(&ng_freenodes, node, nd_nodes);	\
364 		node->nd_magic = 0;					\
365 		mtx_unlock(&ng_nodelist_mtx);				\
366 	} while (0)
367 
368 #else /* NETGRAPH_DEBUG */ /*----------------------------------------------*/
369 
370 #define NG_ALLOC_HOOK(hook) _NG_ALLOC_HOOK(hook)
371 #define NG_ALLOC_NODE(node) _NG_ALLOC_NODE(node)
372 
373 #define NG_FREE_HOOK(hook) do { free((hook), M_NETGRAPH_HOOK); } while (0)
374 #define NG_FREE_NODE(node) do { free((node), M_NETGRAPH_NODE); } while (0)
375 
376 #endif /* NETGRAPH_DEBUG */ /*----------------------------------------------*/
377 
378 /* Set this to kdb_enter("X") to catch all errors as they occur */
379 #ifndef TRAP_ERROR
380 #define TRAP_ERROR()
381 #endif
382 
383 VNET_DEFINE_STATIC(ng_ID_t, nextID) = 1;
384 #define	V_nextID			VNET(nextID)
385 
386 #ifdef INVARIANTS
387 #define CHECK_DATA_MBUF(m)	do {					\
388 		struct mbuf *n;						\
389 		int total;						\
390 									\
391 		M_ASSERTPKTHDR(m);					\
392 		for (total = 0, n = (m); n != NULL; n = n->m_next) {	\
393 			total += n->m_len;				\
394 			if (n->m_nextpkt != NULL)			\
395 				panic("%s: m_nextpkt", __func__);	\
396 		}							\
397 									\
398 		if ((m)->m_pkthdr.len != total) {			\
399 			panic("%s: %d != %d",				\
400 			    __func__, (m)->m_pkthdr.len, total);	\
401 		}							\
402 	} while (0)
403 #else
404 #define CHECK_DATA_MBUF(m)
405 #endif
406 
407 #define ERROUT(x)	do { error = (x); goto done; } while (0)
408 
409 /************************************************************************
410 	Parse type definitions for generic messages
411 ************************************************************************/
412 
413 /* Handy structure parse type defining macro */
414 #define DEFINE_PARSE_STRUCT_TYPE(lo, up, args)				\
415 static const struct ng_parse_struct_field				\
416 	ng_ ## lo ## _type_fields[] = NG_GENERIC_ ## up ## _INFO args;	\
417 static const struct ng_parse_type ng_generic_ ## lo ## _type = {	\
418 	&ng_parse_struct_type,						\
419 	&ng_ ## lo ## _type_fields					\
420 }
421 
422 DEFINE_PARSE_STRUCT_TYPE(mkpeer, MKPEER, ());
423 DEFINE_PARSE_STRUCT_TYPE(connect, CONNECT, ());
424 DEFINE_PARSE_STRUCT_TYPE(name, NAME, ());
425 DEFINE_PARSE_STRUCT_TYPE(rmhook, RMHOOK, ());
426 DEFINE_PARSE_STRUCT_TYPE(nodeinfo, NODEINFO, ());
427 DEFINE_PARSE_STRUCT_TYPE(typeinfo, TYPEINFO, ());
428 DEFINE_PARSE_STRUCT_TYPE(linkinfo, LINKINFO, (&ng_generic_nodeinfo_type));
429 
430 /* Get length of an array when the length is stored as a 32 bit
431    value immediately preceding the array -- as with struct namelist
432    and struct typelist. */
433 static int
434 ng_generic_list_getLength(const struct ng_parse_type *type,
435 	const u_char *start, const u_char *buf)
436 {
437 	return *((const u_int32_t *)(buf - 4));
438 }
439 
440 /* Get length of the array of struct linkinfo inside a struct hooklist */
441 static int
442 ng_generic_linkinfo_getLength(const struct ng_parse_type *type,
443 	const u_char *start, const u_char *buf)
444 {
445 	const struct hooklist *hl = (const struct hooklist *)start;
446 
447 	return hl->nodeinfo.hooks;
448 }
449 
450 /* Array type for a variable length array of struct namelist */
451 static const struct ng_parse_array_info ng_nodeinfoarray_type_info = {
452 	&ng_generic_nodeinfo_type,
453 	&ng_generic_list_getLength
454 };
455 static const struct ng_parse_type ng_generic_nodeinfoarray_type = {
456 	&ng_parse_array_type,
457 	&ng_nodeinfoarray_type_info
458 };
459 
460 /* Array type for a variable length array of struct typelist */
461 static const struct ng_parse_array_info ng_typeinfoarray_type_info = {
462 	&ng_generic_typeinfo_type,
463 	&ng_generic_list_getLength
464 };
465 static const struct ng_parse_type ng_generic_typeinfoarray_type = {
466 	&ng_parse_array_type,
467 	&ng_typeinfoarray_type_info
468 };
469 
470 /* Array type for array of struct linkinfo in struct hooklist */
471 static const struct ng_parse_array_info ng_generic_linkinfo_array_type_info = {
472 	&ng_generic_linkinfo_type,
473 	&ng_generic_linkinfo_getLength
474 };
475 static const struct ng_parse_type ng_generic_linkinfo_array_type = {
476 	&ng_parse_array_type,
477 	&ng_generic_linkinfo_array_type_info
478 };
479 
480 DEFINE_PARSE_STRUCT_TYPE(typelist, TYPELIST, (&ng_generic_typeinfoarray_type));
481 DEFINE_PARSE_STRUCT_TYPE(hooklist, HOOKLIST,
482 	(&ng_generic_nodeinfo_type, &ng_generic_linkinfo_array_type));
483 DEFINE_PARSE_STRUCT_TYPE(listnodes, LISTNODES,
484 	(&ng_generic_nodeinfoarray_type));
485 
486 /* List of commands and how to convert arguments to/from ASCII */
487 static const struct ng_cmdlist ng_generic_cmds[] = {
488 	{
489 	  NGM_GENERIC_COOKIE,
490 	  NGM_SHUTDOWN,
491 	  "shutdown",
492 	  NULL,
493 	  NULL
494 	},
495 	{
496 	  NGM_GENERIC_COOKIE,
497 	  NGM_MKPEER,
498 	  "mkpeer",
499 	  &ng_generic_mkpeer_type,
500 	  NULL
501 	},
502 	{
503 	  NGM_GENERIC_COOKIE,
504 	  NGM_CONNECT,
505 	  "connect",
506 	  &ng_generic_connect_type,
507 	  NULL
508 	},
509 	{
510 	  NGM_GENERIC_COOKIE,
511 	  NGM_NAME,
512 	  "name",
513 	  &ng_generic_name_type,
514 	  NULL
515 	},
516 	{
517 	  NGM_GENERIC_COOKIE,
518 	  NGM_RMHOOK,
519 	  "rmhook",
520 	  &ng_generic_rmhook_type,
521 	  NULL
522 	},
523 	{
524 	  NGM_GENERIC_COOKIE,
525 	  NGM_NODEINFO,
526 	  "nodeinfo",
527 	  NULL,
528 	  &ng_generic_nodeinfo_type
529 	},
530 	{
531 	  NGM_GENERIC_COOKIE,
532 	  NGM_LISTHOOKS,
533 	  "listhooks",
534 	  NULL,
535 	  &ng_generic_hooklist_type
536 	},
537 	{
538 	  NGM_GENERIC_COOKIE,
539 	  NGM_LISTNAMES,
540 	  "listnames",
541 	  NULL,
542 	  &ng_generic_listnodes_type	/* same as NGM_LISTNODES */
543 	},
544 	{
545 	  NGM_GENERIC_COOKIE,
546 	  NGM_LISTNODES,
547 	  "listnodes",
548 	  NULL,
549 	  &ng_generic_listnodes_type
550 	},
551 	{
552 	  NGM_GENERIC_COOKIE,
553 	  NGM_LISTTYPES,
554 	  "listtypes",
555 	  NULL,
556 	  &ng_generic_typelist_type
557 	},
558 	{
559 	  NGM_GENERIC_COOKIE,
560 	  NGM_TEXT_CONFIG,
561 	  "textconfig",
562 	  NULL,
563 	  &ng_parse_string_type
564 	},
565 	{
566 	  NGM_GENERIC_COOKIE,
567 	  NGM_TEXT_STATUS,
568 	  "textstatus",
569 	  NULL,
570 	  &ng_parse_string_type
571 	},
572 	{
573 	  NGM_GENERIC_COOKIE,
574 	  NGM_ASCII2BINARY,
575 	  "ascii2binary",
576 	  &ng_parse_ng_mesg_type,
577 	  &ng_parse_ng_mesg_type
578 	},
579 	{
580 	  NGM_GENERIC_COOKIE,
581 	  NGM_BINARY2ASCII,
582 	  "binary2ascii",
583 	  &ng_parse_ng_mesg_type,
584 	  &ng_parse_ng_mesg_type
585 	},
586 	{ 0 }
587 };
588 
589 /************************************************************************
590 			Node routines
591 ************************************************************************/
592 
593 /*
594  * Instantiate a node of the requested type
595  */
596 int
597 ng_make_node(const char *typename, node_p *nodepp)
598 {
599 	struct ng_type *type;
600 	int	error;
601 
602 	/* Check that the type makes sense */
603 	if (typename == NULL) {
604 		TRAP_ERROR();
605 		return (EINVAL);
606 	}
607 
608 	/* Locate the node type. If we fail we return. Do not try to load
609 	 * module.
610 	 */
611 	if ((type = ng_findtype(typename)) == NULL)
612 		return (ENXIO);
613 
614 	/*
615 	 * If we have a constructor, then make the node and
616 	 * call the constructor to do type specific initialisation.
617 	 */
618 	if (type->constructor != NULL) {
619 		if ((error = ng_make_node_common(type, nodepp)) == 0) {
620 			if ((error = ((*type->constructor)(*nodepp))) != 0) {
621 				NG_NODE_UNREF(*nodepp);
622 			}
623 		}
624 	} else {
625 		/*
626 		 * Node has no constructor. We cannot ask for one
627 		 * to be made. It must be brought into existence by
628 		 * some external agency. The external agency should
629 		 * call ng_make_node_common() directly to get the
630 		 * netgraph part initialised.
631 		 */
632 		TRAP_ERROR();
633 		error = EINVAL;
634 	}
635 	return (error);
636 }
637 
638 /*
639  * Generic node creation. Called by node initialisation for externally
640  * instantiated nodes (e.g. hardware, sockets, etc ).
641  * The returned node has a reference count of 1.
642  */
643 int
644 ng_make_node_common(struct ng_type *type, node_p *nodepp)
645 {
646 	node_p node;
647 
648 	/* Require the node type to have been already installed */
649 	if (ng_findtype(type->name) == NULL) {
650 		TRAP_ERROR();
651 		return (EINVAL);
652 	}
653 
654 	/* Make a node and try attach it to the type */
655 	NG_ALLOC_NODE(node);
656 	if (node == NULL) {
657 		TRAP_ERROR();
658 		return (ENOMEM);
659 	}
660 	node->nd_type = type;
661 #ifdef VIMAGE
662 	node->nd_vnet = curvnet;
663 #endif
664 	NG_NODE_REF(node);				/* note reference */
665 	type->refs++;
666 
667 	NG_QUEUE_LOCK_INIT(&node->nd_input_queue);
668 	STAILQ_INIT(&node->nd_input_queue.queue);
669 	node->nd_input_queue.q_flags = 0;
670 
671 	/* Initialize hook list for new node */
672 	LIST_INIT(&node->nd_hooks);
673 
674 	/* Get an ID and put us in the hash chain. */
675 	IDHASH_WLOCK();
676 	for (;;) { /* wrap protection, even if silly */
677 		node_p node2 = NULL;
678 		node->nd_ID = V_nextID++; /* 137/sec for 1 year before wrap */
679 
680 		/* Is there a problem with the new number? */
681 		NG_IDHASH_FIND(node->nd_ID, node2); /* already taken? */
682 		if ((node->nd_ID != 0) && (node2 == NULL)) {
683 			break;
684 		}
685 	}
686 	V_ng_nodes++;
687 	if (V_ng_nodes * 2 > V_ng_ID_hmask)
688 		ng_ID_rehash();
689 	LIST_INSERT_HEAD(&V_ng_ID_hash[NG_IDHASH_FN(node->nd_ID)], node,
690 	    nd_idnodes);
691 	IDHASH_WUNLOCK();
692 
693 	/* Done */
694 	*nodepp = node;
695 	return (0);
696 }
697 
698 /*
699  * Forceably start the shutdown process on a node. Either call
700  * its shutdown method, or do the default shutdown if there is
701  * no type-specific method.
702  *
703  * We can only be called from a shutdown message, so we know we have
704  * a writer lock, and therefore exclusive access. It also means
705  * that we should not be on the work queue, but we check anyhow.
706  *
707  * Persistent node types must have a type-specific method which
708  * allocates a new node in which case, this one is irretrievably going away,
709  * or cleans up anything it needs, and just makes the node valid again,
710  * in which case we allow the node to survive.
711  *
712  * XXX We need to think of how to tell a persistent node that we
713  * REALLY need to go away because the hardware has gone or we
714  * are rebooting.... etc.
715  */
716 void
717 ng_rmnode(node_p node, hook_p dummy1, void *dummy2, int dummy3)
718 {
719 	hook_p hook;
720 
721 	/* Check if it's already shutting down */
722 	if ((node->nd_flags & NGF_CLOSING) != 0)
723 		return;
724 
725 	if (node == &ng_deadnode) {
726 		printf ("shutdown called on deadnode\n");
727 		return;
728 	}
729 
730 	/* Add an extra reference so it doesn't go away during this */
731 	NG_NODE_REF(node);
732 
733 	/*
734 	 * Mark it invalid so any newcomers know not to try use it
735 	 * Also add our own mark so we can't recurse
736 	 * note that NGF_INVALID does not do this as it's also set during
737 	 * creation
738 	 */
739 	node->nd_flags |= NGF_INVALID|NGF_CLOSING;
740 
741 	/* If node has its pre-shutdown method, then call it first*/
742 	if (node->nd_type && node->nd_type->close)
743 		(*node->nd_type->close)(node);
744 
745 	/* Notify all remaining connected nodes to disconnect */
746 	while ((hook = LIST_FIRST(&node->nd_hooks)) != NULL)
747 		ng_destroy_hook(hook);
748 
749 	/*
750 	 * Drain the input queue forceably.
751 	 * it has no hooks so what's it going to do, bleed on someone?
752 	 * Theoretically we came here from a queue entry that was added
753 	 * Just before the queue was closed, so it should be empty anyway.
754 	 * Also removes us from worklist if needed.
755 	 */
756 	ng_flush_input_queue(node);
757 
758 	/* Ask the type if it has anything to do in this case */
759 	if (node->nd_type && node->nd_type->shutdown) {
760 		(*node->nd_type->shutdown)(node);
761 		if (NG_NODE_IS_VALID(node)) {
762 			/*
763 			 * Well, blow me down if the node code hasn't declared
764 			 * that it doesn't want to die.
765 			 * Presumably it is a persistent node.
766 			 * If we REALLY want it to go away,
767 			 *  e.g. hardware going away,
768 			 * Our caller should set NGF_REALLY_DIE in nd_flags.
769 			 */
770 			node->nd_flags &= ~(NGF_INVALID|NGF_CLOSING);
771 			NG_NODE_UNREF(node); /* Assume they still have theirs */
772 			return;
773 		}
774 	} else {				/* do the default thing */
775 		NG_NODE_UNREF(node);
776 	}
777 
778 	ng_unname(node); /* basically a NOP these days */
779 
780 	/*
781 	 * Remove extra reference, possibly the last
782 	 * Possible other holders of references may include
783 	 * timeout callouts, but theoretically the node's supposed to
784 	 * have cancelled them. Possibly hardware dependencies may
785 	 * force a driver to 'linger' with a reference.
786 	 */
787 	NG_NODE_UNREF(node);
788 }
789 
790 /*
791  * Remove a reference to the node, possibly the last.
792  * deadnode always acts as it were the last.
793  */
794 void
795 ng_unref_node(node_p node)
796 {
797 
798 	if (node == &ng_deadnode)
799 		return;
800 
801 	CURVNET_SET(node->nd_vnet);
802 
803 	if (refcount_release(&node->nd_refs)) { /* we were the last */
804 
805 		node->nd_type->refs--; /* XXX maybe should get types lock? */
806 		NAMEHASH_WLOCK();
807 		if (NG_NODE_HAS_NAME(node)) {
808 			V_ng_named_nodes--;
809 			LIST_REMOVE(node, nd_nodes);
810 		}
811 		NAMEHASH_WUNLOCK();
812 
813 		IDHASH_WLOCK();
814 		V_ng_nodes--;
815 		LIST_REMOVE(node, nd_idnodes);
816 		IDHASH_WUNLOCK();
817 
818 		mtx_destroy(&node->nd_input_queue.q_mtx);
819 		NG_FREE_NODE(node);
820 	}
821 	CURVNET_RESTORE();
822 }
823 
824 /************************************************************************
825 			Node ID handling
826 ************************************************************************/
827 static node_p
828 ng_ID2noderef(ng_ID_t ID)
829 {
830 	node_p node;
831 
832 	IDHASH_RLOCK();
833 	NG_IDHASH_FIND(ID, node);
834 	if (node)
835 		NG_NODE_REF(node);
836 	IDHASH_RUNLOCK();
837 	return(node);
838 }
839 
840 ng_ID_t
841 ng_node2ID(node_cp node)
842 {
843 	return (node ? NG_NODE_ID(node) : 0);
844 }
845 
846 /************************************************************************
847 			Node name handling
848 ************************************************************************/
849 
850 /*
851  * Assign a node a name.
852  */
853 int
854 ng_name_node(node_p node, const char *name)
855 {
856 	uint32_t hash;
857 	node_p node2;
858 	int i;
859 
860 	/* Rename without change is a noop */
861 	if (strcmp(NG_NODE_NAME(node), name) == 0)
862 		return (0);
863 
864 	/* Check the name is valid */
865 	for (i = 0; i < NG_NODESIZ; i++) {
866 		if (name[i] == '\0' || name[i] == '.' || name[i] == ':')
867 			break;
868 	}
869 	if (i == 0 || name[i] != '\0') {
870 		TRAP_ERROR();
871 		return (EINVAL);
872 	}
873 	if (ng_decodeidname(name) != 0) { /* valid IDs not allowed here */
874 		TRAP_ERROR();
875 		return (EINVAL);
876 	}
877 
878 	NAMEHASH_WLOCK();
879 	if (V_ng_named_nodes * 2 > V_ng_name_hmask)
880 		ng_name_rehash();
881 
882 	hash = hash32_str(name, HASHINIT) & V_ng_name_hmask;
883 	/* Check the name isn't already being used. */
884 	LIST_FOREACH(node2, &V_ng_name_hash[hash], nd_nodes)
885 		if (NG_NODE_IS_VALID(node2) &&
886 		    (strcmp(NG_NODE_NAME(node2), name) == 0)) {
887 			NAMEHASH_WUNLOCK();
888 			return (EADDRINUSE);
889 		}
890 
891 	if (NG_NODE_HAS_NAME(node))
892 		LIST_REMOVE(node, nd_nodes);
893 	else
894 		V_ng_named_nodes++;
895 	/* Copy it. */
896 	strlcpy(NG_NODE_NAME(node), name, NG_NODESIZ);
897 	/* Update name hash. */
898 	LIST_INSERT_HEAD(&V_ng_name_hash[hash], node, nd_nodes);
899 	NAMEHASH_WUNLOCK();
900 
901 	return (0);
902 }
903 
904 /*
905  * Find a node by absolute name. The name should NOT end with ':'
906  * The name "." means "this node" and "[xxx]" means "the node
907  * with ID (ie, at address) xxx".
908  *
909  * Returns the node if found, else NULL.
910  * Eventually should add something faster than a sequential search.
911  * Note it acquires a reference on the node so you can be sure it's still
912  * there.
913  */
914 node_p
915 ng_name2noderef(node_p here, const char *name)
916 {
917 	node_p node;
918 	ng_ID_t temp;
919 	int	hash;
920 
921 	/* "." means "this node" */
922 	if (strcmp(name, ".") == 0) {
923 		NG_NODE_REF(here);
924 		return(here);
925 	}
926 
927 	/* Check for name-by-ID */
928 	if ((temp = ng_decodeidname(name)) != 0) {
929 		return (ng_ID2noderef(temp));
930 	}
931 
932 	/* Find node by name. */
933 	hash = hash32_str(name, HASHINIT) & V_ng_name_hmask;
934 	NAMEHASH_RLOCK();
935 	LIST_FOREACH(node, &V_ng_name_hash[hash], nd_nodes)
936 		if (NG_NODE_IS_VALID(node) &&
937 		    (strcmp(NG_NODE_NAME(node), name) == 0)) {
938 			NG_NODE_REF(node);
939 			break;
940 		}
941 	NAMEHASH_RUNLOCK();
942 
943 	return (node);
944 }
945 
946 /*
947  * Decode an ID name, eg. "[f03034de]". Returns 0 if the
948  * string is not valid, otherwise returns the value.
949  */
950 static ng_ID_t
951 ng_decodeidname(const char *name)
952 {
953 	const int len = strlen(name);
954 	char *eptr;
955 	u_long val;
956 
957 	/* Check for proper length, brackets, no leading junk */
958 	if ((len < 3) || (name[0] != '[') || (name[len - 1] != ']') ||
959 	    (!isxdigit(name[1])))
960 		return ((ng_ID_t)0);
961 
962 	/* Decode number */
963 	val = strtoul(name + 1, &eptr, 16);
964 	if ((eptr - name != len - 1) || (val == ULONG_MAX) || (val == 0))
965 		return ((ng_ID_t)0);
966 
967 	return ((ng_ID_t)val);
968 }
969 
970 /*
971  * Remove a name from a node. This should only be called
972  * when shutting down and removing the node.
973  */
974 void
975 ng_unname(node_p node)
976 {
977 }
978 
979 /*
980  * Allocate a bigger name hash.
981  */
982 static void
983 ng_name_rehash(void)
984 {
985 	struct nodehash *new;
986 	uint32_t hash;
987 	u_long hmask;
988 	node_p node, node2;
989 	int i;
990 
991 	new = hashinit_flags((V_ng_name_hmask + 1) * 2, M_NETGRAPH_NODE, &hmask,
992 	    HASH_NOWAIT);
993 	if (new == NULL)
994 		return;
995 
996 	for (i = 0; i <= V_ng_name_hmask; i++)
997 		LIST_FOREACH_SAFE(node, &V_ng_name_hash[i], nd_nodes, node2) {
998 #ifdef INVARIANTS
999 			LIST_REMOVE(node, nd_nodes);
1000 #endif
1001 			hash = hash32_str(NG_NODE_NAME(node), HASHINIT) & hmask;
1002 			LIST_INSERT_HEAD(&new[hash], node, nd_nodes);
1003 		}
1004 
1005 	hashdestroy(V_ng_name_hash, M_NETGRAPH_NODE, V_ng_name_hmask);
1006 	V_ng_name_hash = new;
1007 	V_ng_name_hmask = hmask;
1008 }
1009 
1010 /*
1011  * Allocate a bigger ID hash.
1012  */
1013 static void
1014 ng_ID_rehash(void)
1015 {
1016 	struct nodehash *new;
1017 	uint32_t hash;
1018 	u_long hmask;
1019 	node_p node, node2;
1020 	int i;
1021 
1022 	new = hashinit_flags((V_ng_ID_hmask + 1) * 2, M_NETGRAPH_NODE, &hmask,
1023 	    HASH_NOWAIT);
1024 	if (new == NULL)
1025 		return;
1026 
1027 	for (i = 0; i <= V_ng_ID_hmask; i++)
1028 		LIST_FOREACH_SAFE(node, &V_ng_ID_hash[i], nd_idnodes, node2) {
1029 #ifdef INVARIANTS
1030 			LIST_REMOVE(node, nd_idnodes);
1031 #endif
1032 			hash = (node->nd_ID % (hmask + 1));
1033 			LIST_INSERT_HEAD(&new[hash], node, nd_idnodes);
1034 		}
1035 
1036 	hashdestroy(V_ng_ID_hash, M_NETGRAPH_NODE, V_ng_name_hmask);
1037 	V_ng_ID_hash = new;
1038 	V_ng_ID_hmask = hmask;
1039 }
1040 
1041 /************************************************************************
1042 			Hook routines
1043  Names are not optional. Hooks are always connected, except for a
1044  brief moment within these routines. On invalidation or during creation
1045  they are connected to the 'dead' hook.
1046 ************************************************************************/
1047 
1048 /*
1049  * Remove a hook reference
1050  */
1051 void
1052 ng_unref_hook(hook_p hook)
1053 {
1054 
1055 	if (hook == &ng_deadhook)
1056 		return;
1057 
1058 	if (refcount_release(&hook->hk_refs)) { /* we were the last */
1059 		if (_NG_HOOK_NODE(hook)) /* it'll probably be ng_deadnode */
1060 			_NG_NODE_UNREF((_NG_HOOK_NODE(hook)));
1061 		NG_FREE_HOOK(hook);
1062 	}
1063 }
1064 
1065 /*
1066  * Add an unconnected hook to a node. Only used internally.
1067  * Assumes node is locked. (XXX not yet true )
1068  */
1069 static int
1070 ng_add_hook(node_p node, const char *name, hook_p *hookp)
1071 {
1072 	hook_p hook;
1073 	int error = 0;
1074 
1075 	/* Check that the given name is good */
1076 	if (name == NULL) {
1077 		TRAP_ERROR();
1078 		return (EINVAL);
1079 	}
1080 	if (ng_findhook(node, name) != NULL) {
1081 		TRAP_ERROR();
1082 		return (EEXIST);
1083 	}
1084 
1085 	/* Allocate the hook and link it up */
1086 	NG_ALLOC_HOOK(hook);
1087 	if (hook == NULL) {
1088 		TRAP_ERROR();
1089 		return (ENOMEM);
1090 	}
1091 	hook->hk_refs = 1;		/* add a reference for us to return */
1092 	hook->hk_flags = HK_INVALID;
1093 	hook->hk_peer = &ng_deadhook;	/* start off this way */
1094 	hook->hk_node = node;
1095 	NG_NODE_REF(node);		/* each hook counts as a reference */
1096 
1097 	/* Set hook name */
1098 	strlcpy(NG_HOOK_NAME(hook), name, NG_HOOKSIZ);
1099 
1100 	/*
1101 	 * Check if the node type code has something to say about it
1102 	 * If it fails, the unref of the hook will also unref the node.
1103 	 */
1104 	if (node->nd_type->newhook != NULL) {
1105 		if ((error = (*node->nd_type->newhook)(node, hook, name))) {
1106 			NG_HOOK_UNREF(hook);	/* this frees the hook */
1107 			return (error);
1108 		}
1109 	}
1110 	/*
1111 	 * The 'type' agrees so far, so go ahead and link it in.
1112 	 * We'll ask again later when we actually connect the hooks.
1113 	 */
1114 	LIST_INSERT_HEAD(&node->nd_hooks, hook, hk_hooks);
1115 	node->nd_numhooks++;
1116 	NG_HOOK_REF(hook);	/* one for the node */
1117 
1118 	if (hookp)
1119 		*hookp = hook;
1120 	return (0);
1121 }
1122 
1123 /*
1124  * Find a hook
1125  *
1126  * Node types may supply their own optimized routines for finding
1127  * hooks.  If none is supplied, we just do a linear search.
1128  * XXX Possibly we should add a reference to the hook?
1129  */
1130 hook_p
1131 ng_findhook(node_p node, const char *name)
1132 {
1133 	hook_p hook;
1134 
1135 	if (node->nd_type->findhook != NULL)
1136 		return (*node->nd_type->findhook)(node, name);
1137 	LIST_FOREACH(hook, &node->nd_hooks, hk_hooks) {
1138 		if (NG_HOOK_IS_VALID(hook) &&
1139 		    (strcmp(NG_HOOK_NAME(hook), name) == 0))
1140 			return (hook);
1141 	}
1142 	return (NULL);
1143 }
1144 
1145 /*
1146  * Destroy a hook
1147  *
1148  * As hooks are always attached, this really destroys two hooks.
1149  * The one given, and the one attached to it. Disconnect the hooks
1150  * from each other first. We reconnect the peer hook to the 'dead'
1151  * hook so that it can still exist after we depart. We then
1152  * send the peer its own destroy message. This ensures that we only
1153  * interact with the peer's structures when it is locked processing that
1154  * message. We hold a reference to the peer hook so we are guaranteed that
1155  * the peer hook and node are still going to exist until
1156  * we are finished there as the hook holds a ref on the node.
1157  * We run this same code again on the peer hook, but that time it is already
1158  * attached to the 'dead' hook.
1159  *
1160  * This routine is called at all stages of hook creation
1161  * on error detection and must be able to handle any such stage.
1162  */
1163 void
1164 ng_destroy_hook(hook_p hook)
1165 {
1166 	hook_p peer;
1167 	node_p node;
1168 
1169 	if (hook == &ng_deadhook) {	/* better safe than sorry */
1170 		printf("ng_destroy_hook called on deadhook\n");
1171 		return;
1172 	}
1173 
1174 	/*
1175 	 * Protect divorce process with mutex, to avoid races on
1176 	 * simultaneous disconnect.
1177 	 */
1178 	TOPOLOGY_WLOCK();
1179 
1180 	hook->hk_flags |= HK_INVALID;
1181 
1182 	peer = NG_HOOK_PEER(hook);
1183 	node = NG_HOOK_NODE(hook);
1184 
1185 	if (peer && (peer != &ng_deadhook)) {
1186 		/*
1187 		 * Set the peer to point to ng_deadhook
1188 		 * from this moment on we are effectively independent it.
1189 		 * send it an rmhook message of its own.
1190 		 */
1191 		peer->hk_peer = &ng_deadhook;	/* They no longer know us */
1192 		hook->hk_peer = &ng_deadhook;	/* Nor us, them */
1193 		if (NG_HOOK_NODE(peer) == &ng_deadnode) {
1194 			/*
1195 			 * If it's already divorced from a node,
1196 			 * just free it.
1197 			 */
1198 			TOPOLOGY_WUNLOCK();
1199 		} else {
1200 			TOPOLOGY_WUNLOCK();
1201 			ng_rmhook_self(peer); 	/* Send it a surprise */
1202 		}
1203 		NG_HOOK_UNREF(peer);		/* account for peer link */
1204 		NG_HOOK_UNREF(hook);		/* account for peer link */
1205 	} else
1206 		TOPOLOGY_WUNLOCK();
1207 
1208 	TOPOLOGY_NOTOWNED();
1209 
1210 	/*
1211 	 * Remove the hook from the node's list to avoid possible recursion
1212 	 * in case the disconnection results in node shutdown.
1213 	 */
1214 	if (node == &ng_deadnode) { /* happens if called from ng_con_nodes() */
1215 		return;
1216 	}
1217 	LIST_REMOVE(hook, hk_hooks);
1218 	node->nd_numhooks--;
1219 	if (node->nd_type->disconnect) {
1220 		/*
1221 		 * The type handler may elect to destroy the node so don't
1222 		 * trust its existence after this point. (except
1223 		 * that we still hold a reference on it. (which we
1224 		 * inherrited from the hook we are destroying)
1225 		 */
1226 		(*node->nd_type->disconnect) (hook);
1227 	}
1228 
1229 	/*
1230 	 * Note that because we will point to ng_deadnode, the original node
1231 	 * is not decremented automatically so we do that manually.
1232 	 */
1233 	_NG_HOOK_NODE(hook) = &ng_deadnode;
1234 	NG_NODE_UNREF(node);	/* We no longer point to it so adjust count */
1235 	NG_HOOK_UNREF(hook);	/* Account for linkage (in list) to node */
1236 }
1237 
1238 /*
1239  * Take two hooks on a node and merge the connection so that the given node
1240  * is effectively bypassed.
1241  */
1242 int
1243 ng_bypass(hook_p hook1, hook_p hook2)
1244 {
1245 	if (hook1->hk_node != hook2->hk_node) {
1246 		TRAP_ERROR();
1247 		return (EINVAL);
1248 	}
1249 	TOPOLOGY_WLOCK();
1250 	if (NG_HOOK_NOT_VALID(hook1) || NG_HOOK_NOT_VALID(hook2)) {
1251 		TOPOLOGY_WUNLOCK();
1252 		return (EINVAL);
1253 	}
1254 	hook1->hk_peer->hk_peer = hook2->hk_peer;
1255 	hook2->hk_peer->hk_peer = hook1->hk_peer;
1256 
1257 	hook1->hk_peer = &ng_deadhook;
1258 	hook2->hk_peer = &ng_deadhook;
1259 	TOPOLOGY_WUNLOCK();
1260 
1261 	NG_HOOK_UNREF(hook1);
1262 	NG_HOOK_UNREF(hook2);
1263 
1264 	/* XXX If we ever cache methods on hooks update them as well */
1265 	ng_destroy_hook(hook1);
1266 	ng_destroy_hook(hook2);
1267 	return (0);
1268 }
1269 
1270 /*
1271  * Install a new netgraph type
1272  */
1273 int
1274 ng_newtype(struct ng_type *tp)
1275 {
1276 	const size_t namelen = strlen(tp->name);
1277 
1278 	/* Check version and type name fields */
1279 	if ((tp->version != NG_ABI_VERSION) || (namelen == 0) ||
1280 	    (namelen >= NG_TYPESIZ)) {
1281 		TRAP_ERROR();
1282 		if (tp->version != NG_ABI_VERSION) {
1283 			printf("Netgraph: Node type rejected. ABI mismatch. "
1284 			    "Suggest recompile\n");
1285 		}
1286 		return (EINVAL);
1287 	}
1288 
1289 	/* Check for name collision */
1290 	if (ng_findtype(tp->name) != NULL) {
1291 		TRAP_ERROR();
1292 		return (EEXIST);
1293 	}
1294 
1295 	/* Link in new type */
1296 	TYPELIST_WLOCK();
1297 	LIST_INSERT_HEAD(&ng_typelist, tp, types);
1298 	tp->refs = 1;	/* first ref is linked list */
1299 	TYPELIST_WUNLOCK();
1300 	return (0);
1301 }
1302 
1303 /*
1304  * unlink a netgraph type
1305  * If no examples exist
1306  */
1307 int
1308 ng_rmtype(struct ng_type *tp)
1309 {
1310 	/* Check for name collision */
1311 	if (tp->refs != 1) {
1312 		TRAP_ERROR();
1313 		return (EBUSY);
1314 	}
1315 
1316 	/* Unlink type */
1317 	TYPELIST_WLOCK();
1318 	LIST_REMOVE(tp, types);
1319 	TYPELIST_WUNLOCK();
1320 	return (0);
1321 }
1322 
1323 /*
1324  * Look for a type of the name given
1325  */
1326 struct ng_type *
1327 ng_findtype(const char *typename)
1328 {
1329 	struct ng_type *type;
1330 
1331 	TYPELIST_RLOCK();
1332 	LIST_FOREACH(type, &ng_typelist, types) {
1333 		if (strcmp(type->name, typename) == 0)
1334 			break;
1335 	}
1336 	TYPELIST_RUNLOCK();
1337 	return (type);
1338 }
1339 
1340 /************************************************************************
1341 			Composite routines
1342 ************************************************************************/
1343 /*
1344  * Connect two nodes using the specified hooks, using queued functions.
1345  */
1346 static int
1347 ng_con_part3(node_p node, item_p item, hook_p hook)
1348 {
1349 	int	error = 0;
1350 
1351 	/*
1352 	 * When we run, we know that the node 'node' is locked for us.
1353 	 * Our caller has a reference on the hook.
1354 	 * Our caller has a reference on the node.
1355 	 * (In this case our caller is ng_apply_item() ).
1356 	 * The peer hook has a reference on the hook.
1357 	 * We are all set up except for the final call to the node, and
1358 	 * the clearing of the INVALID flag.
1359 	 */
1360 	if (NG_HOOK_NODE(hook) == &ng_deadnode) {
1361 		/*
1362 		 * The node must have been freed again since we last visited
1363 		 * here. ng_destry_hook() has this effect but nothing else does.
1364 		 * We should just release our references and
1365 		 * free anything we can think of.
1366 		 * Since we know it's been destroyed, and it's our caller
1367 		 * that holds the references, just return.
1368 		 */
1369 		ERROUT(ENOENT);
1370 	}
1371 	if (hook->hk_node->nd_type->connect) {
1372 		if ((error = (*hook->hk_node->nd_type->connect) (hook))) {
1373 			ng_destroy_hook(hook);	/* also zaps peer */
1374 			printf("failed in ng_con_part3()\n");
1375 			ERROUT(error);
1376 		}
1377 	}
1378 	/*
1379 	 *  XXX this is wrong for SMP. Possibly we need
1380 	 * to separate out 'create' and 'invalid' flags.
1381 	 * should only set flags on hooks we have locked under our node.
1382 	 */
1383 	hook->hk_flags &= ~HK_INVALID;
1384 done:
1385 	NG_FREE_ITEM(item);
1386 	return (error);
1387 }
1388 
1389 static int
1390 ng_con_part2(node_p node, item_p item, hook_p hook)
1391 {
1392 	hook_p	peer;
1393 	int	error = 0;
1394 
1395 	/*
1396 	 * When we run, we know that the node 'node' is locked for us.
1397 	 * Our caller has a reference on the hook.
1398 	 * Our caller has a reference on the node.
1399 	 * (In this case our caller is ng_apply_item() ).
1400 	 * The peer hook has a reference on the hook.
1401 	 * our node pointer points to the 'dead' node.
1402 	 * First check the hook name is unique.
1403 	 * Should not happen because we checked before queueing this.
1404 	 */
1405 	if (ng_findhook(node, NG_HOOK_NAME(hook)) != NULL) {
1406 		TRAP_ERROR();
1407 		ng_destroy_hook(hook); /* should destroy peer too */
1408 		printf("failed in ng_con_part2()\n");
1409 		ERROUT(EEXIST);
1410 	}
1411 	/*
1412 	 * Check if the node type code has something to say about it
1413 	 * If it fails, the unref of the hook will also unref the attached node,
1414 	 * however since that node is 'ng_deadnode' this will do nothing.
1415 	 * The peer hook will also be destroyed.
1416 	 */
1417 	if (node->nd_type->newhook != NULL) {
1418 		if ((error = (*node->nd_type->newhook)(node, hook,
1419 		    hook->hk_name))) {
1420 			ng_destroy_hook(hook); /* should destroy peer too */
1421 			printf("failed in ng_con_part2()\n");
1422 			ERROUT(error);
1423 		}
1424 	}
1425 
1426 	/*
1427 	 * The 'type' agrees so far, so go ahead and link it in.
1428 	 * We'll ask again later when we actually connect the hooks.
1429 	 */
1430 	hook->hk_node = node;		/* just overwrite ng_deadnode */
1431 	NG_NODE_REF(node);		/* each hook counts as a reference */
1432 	LIST_INSERT_HEAD(&node->nd_hooks, hook, hk_hooks);
1433 	node->nd_numhooks++;
1434 	NG_HOOK_REF(hook);	/* one for the node */
1435 
1436 	/*
1437 	 * We now have a symmetrical situation, where both hooks have been
1438 	 * linked to their nodes, the newhook methods have been called
1439 	 * And the references are all correct. The hooks are still marked
1440 	 * as invalid, as we have not called the 'connect' methods
1441 	 * yet.
1442 	 * We can call the local one immediately as we have the
1443 	 * node locked, but we need to queue the remote one.
1444 	 */
1445 	if (hook->hk_node->nd_type->connect) {
1446 		if ((error = (*hook->hk_node->nd_type->connect) (hook))) {
1447 			ng_destroy_hook(hook);	/* also zaps peer */
1448 			printf("failed in ng_con_part2(A)\n");
1449 			ERROUT(error);
1450 		}
1451 	}
1452 
1453 	/*
1454 	 * Acquire topo mutex to avoid race with ng_destroy_hook().
1455 	 */
1456 	TOPOLOGY_RLOCK();
1457 	peer = hook->hk_peer;
1458 	if (peer == &ng_deadhook) {
1459 		TOPOLOGY_RUNLOCK();
1460 		printf("failed in ng_con_part2(B)\n");
1461 		ng_destroy_hook(hook);
1462 		ERROUT(ENOENT);
1463 	}
1464 	TOPOLOGY_RUNLOCK();
1465 
1466 	if ((error = ng_send_fn2(peer->hk_node, peer, item, &ng_con_part3,
1467 	    NULL, 0, NG_REUSE_ITEM))) {
1468 		printf("failed in ng_con_part2(C)\n");
1469 		ng_destroy_hook(hook);	/* also zaps peer */
1470 		return (error);		/* item was consumed. */
1471 	}
1472 	hook->hk_flags &= ~HK_INVALID; /* need both to be able to work */
1473 	return (0);			/* item was consumed. */
1474 done:
1475 	NG_FREE_ITEM(item);
1476 	return (error);
1477 }
1478 
1479 /*
1480  * Connect this node with another node. We assume that this node is
1481  * currently locked, as we are only called from an NGM_CONNECT message.
1482  */
1483 static int
1484 ng_con_nodes(item_p item, node_p node, const char *name,
1485     node_p node2, const char *name2)
1486 {
1487 	int	error;
1488 	hook_p	hook;
1489 	hook_p	hook2;
1490 
1491 	if (ng_findhook(node2, name2) != NULL) {
1492 		return(EEXIST);
1493 	}
1494 	if ((error = ng_add_hook(node, name, &hook)))  /* gives us a ref */
1495 		return (error);
1496 	/* Allocate the other hook and link it up */
1497 	NG_ALLOC_HOOK(hook2);
1498 	if (hook2 == NULL) {
1499 		TRAP_ERROR();
1500 		ng_destroy_hook(hook);	/* XXX check ref counts so far */
1501 		NG_HOOK_UNREF(hook);	/* including our ref */
1502 		return (ENOMEM);
1503 	}
1504 	hook2->hk_refs = 1;		/* start with a reference for us. */
1505 	hook2->hk_flags = HK_INVALID;
1506 	hook2->hk_peer = hook;		/* Link the two together */
1507 	hook->hk_peer = hook2;
1508 	NG_HOOK_REF(hook);		/* Add a ref for the peer to each*/
1509 	NG_HOOK_REF(hook2);
1510 	hook2->hk_node = &ng_deadnode;
1511 	strlcpy(NG_HOOK_NAME(hook2), name2, NG_HOOKSIZ);
1512 
1513 	/*
1514 	 * Queue the function above.
1515 	 * Procesing continues in that function in the lock context of
1516 	 * the other node.
1517 	 */
1518 	if ((error = ng_send_fn2(node2, hook2, item, &ng_con_part2, NULL, 0,
1519 	    NG_NOFLAGS))) {
1520 		printf("failed in ng_con_nodes(): %d\n", error);
1521 		ng_destroy_hook(hook);	/* also zaps peer */
1522 	}
1523 
1524 	NG_HOOK_UNREF(hook);		/* Let each hook go if it wants to */
1525 	NG_HOOK_UNREF(hook2);
1526 	return (error);
1527 }
1528 
1529 /*
1530  * Make a peer and connect.
1531  * We assume that the local node is locked.
1532  * The new node probably doesn't need a lock until
1533  * it has a hook, because it cannot really have any work until then,
1534  * but we should think about it a bit more.
1535  *
1536  * The problem may come if the other node also fires up
1537  * some hardware or a timer or some other source of activation,
1538  * also it may already get a command msg via it's ID.
1539  *
1540  * We could use the same method as ng_con_nodes() but we'd have
1541  * to add ability to remove the node when failing. (Not hard, just
1542  * make arg1 point to the node to remove).
1543  * Unless of course we just ignore failure to connect and leave
1544  * an unconnected node?
1545  */
1546 static int
1547 ng_mkpeer(node_p node, const char *name, const char *name2, char *type)
1548 {
1549 	node_p	node2;
1550 	hook_p	hook1, hook2;
1551 	int	error;
1552 
1553 	if ((error = ng_make_node(type, &node2))) {
1554 		return (error);
1555 	}
1556 
1557 	if ((error = ng_add_hook(node, name, &hook1))) { /* gives us a ref */
1558 		ng_rmnode(node2, NULL, NULL, 0);
1559 		return (error);
1560 	}
1561 
1562 	if ((error = ng_add_hook(node2, name2, &hook2))) {
1563 		ng_rmnode(node2, NULL, NULL, 0);
1564 		ng_destroy_hook(hook1);
1565 		NG_HOOK_UNREF(hook1);
1566 		return (error);
1567 	}
1568 
1569 	/*
1570 	 * Actually link the two hooks together.
1571 	 */
1572 	hook1->hk_peer = hook2;
1573 	hook2->hk_peer = hook1;
1574 
1575 	/* Each hook is referenced by the other */
1576 	NG_HOOK_REF(hook1);
1577 	NG_HOOK_REF(hook2);
1578 
1579 	/* Give each node the opportunity to veto the pending connection */
1580 	if (hook1->hk_node->nd_type->connect) {
1581 		error = (*hook1->hk_node->nd_type->connect) (hook1);
1582 	}
1583 
1584 	if ((error == 0) && hook2->hk_node->nd_type->connect) {
1585 		error = (*hook2->hk_node->nd_type->connect) (hook2);
1586 	}
1587 
1588 	/*
1589 	 * drop the references we were holding on the two hooks.
1590 	 */
1591 	if (error) {
1592 		ng_destroy_hook(hook2);	/* also zaps hook1 */
1593 		ng_rmnode(node2, NULL, NULL, 0);
1594 	} else {
1595 		/* As a last act, allow the hooks to be used */
1596 		hook1->hk_flags &= ~HK_INVALID;
1597 		hook2->hk_flags &= ~HK_INVALID;
1598 	}
1599 	NG_HOOK_UNREF(hook1);
1600 	NG_HOOK_UNREF(hook2);
1601 	return (error);
1602 }
1603 
1604 /************************************************************************
1605 		Utility routines to send self messages
1606 ************************************************************************/
1607 
1608 /* Shut this node down as soon as everyone is clear of it */
1609 /* Should add arg "immediately" to jump the queue */
1610 int
1611 ng_rmnode_self(node_p node)
1612 {
1613 	int		error;
1614 
1615 	if (node == &ng_deadnode)
1616 		return (0);
1617 	node->nd_flags |= NGF_INVALID;
1618 	if (node->nd_flags & NGF_CLOSING)
1619 		return (0);
1620 
1621 	error = ng_send_fn(node, NULL, &ng_rmnode, NULL, 0);
1622 	return (error);
1623 }
1624 
1625 static void
1626 ng_rmhook_part2(node_p node, hook_p hook, void *arg1, int arg2)
1627 {
1628 	ng_destroy_hook(hook);
1629 	return ;
1630 }
1631 
1632 int
1633 ng_rmhook_self(hook_p hook)
1634 {
1635 	int		error;
1636 	node_p node = NG_HOOK_NODE(hook);
1637 
1638 	if (node == &ng_deadnode)
1639 		return (0);
1640 
1641 	error = ng_send_fn(node, hook, &ng_rmhook_part2, NULL, 0);
1642 	return (error);
1643 }
1644 
1645 /***********************************************************************
1646  * Parse and verify a string of the form:  <NODE:><PATH>
1647  *
1648  * Such a string can refer to a specific node or a specific hook
1649  * on a specific node, depending on how you look at it. In the
1650  * latter case, the PATH component must not end in a dot.
1651  *
1652  * Both <NODE:> and <PATH> are optional. The <PATH> is a string
1653  * of hook names separated by dots. This breaks out the original
1654  * string, setting *nodep to "NODE" (or NULL if none) and *pathp
1655  * to "PATH" (or NULL if degenerate). Also, *hookp will point to
1656  * the final hook component of <PATH>, if any, otherwise NULL.
1657  *
1658  * This returns -1 if the path is malformed. The char ** are optional.
1659  ***********************************************************************/
1660 int
1661 ng_path_parse(char *addr, char **nodep, char **pathp, char **hookp)
1662 {
1663 	char	*node, *path, *hook;
1664 	int	k;
1665 
1666 	/*
1667 	 * Extract absolute NODE, if any
1668 	 */
1669 	for (path = addr; *path && *path != ':'; path++);
1670 	if (*path) {
1671 		node = addr;	/* Here's the NODE */
1672 		*path++ = '\0';	/* Here's the PATH */
1673 
1674 		/* Node name must not be empty */
1675 		if (!*node)
1676 			return -1;
1677 
1678 		/* A name of "." is OK; otherwise '.' not allowed */
1679 		if (strcmp(node, ".") != 0) {
1680 			for (k = 0; node[k]; k++)
1681 				if (node[k] == '.')
1682 					return -1;
1683 		}
1684 	} else {
1685 		node = NULL;	/* No absolute NODE */
1686 		path = addr;	/* Here's the PATH */
1687 	}
1688 
1689 	/* Snoop for illegal characters in PATH */
1690 	for (k = 0; path[k]; k++)
1691 		if (path[k] == ':')
1692 			return -1;
1693 
1694 	/* Check for no repeated dots in PATH */
1695 	for (k = 0; path[k]; k++)
1696 		if (path[k] == '.' && path[k + 1] == '.')
1697 			return -1;
1698 
1699 	/* Remove extra (degenerate) dots from beginning or end of PATH */
1700 	if (path[0] == '.')
1701 		path++;
1702 	if (*path && path[strlen(path) - 1] == '.')
1703 		path[strlen(path) - 1] = 0;
1704 
1705 	/* If PATH has a dot, then we're not talking about a hook */
1706 	if (*path) {
1707 		for (hook = path, k = 0; path[k]; k++)
1708 			if (path[k] == '.') {
1709 				hook = NULL;
1710 				break;
1711 			}
1712 	} else
1713 		path = hook = NULL;
1714 
1715 	/* Done */
1716 	if (nodep)
1717 		*nodep = node;
1718 	if (pathp)
1719 		*pathp = path;
1720 	if (hookp)
1721 		*hookp = hook;
1722 	return (0);
1723 }
1724 
1725 /*
1726  * Given a path, which may be absolute or relative, and a starting node,
1727  * return the destination node.
1728  */
1729 int
1730 ng_path2noderef(node_p here, const char *address, node_p *destp,
1731     hook_p *lasthook)
1732 {
1733 	char    fullpath[NG_PATHSIZ];
1734 	char   *nodename, *path;
1735 	node_p  node, oldnode;
1736 
1737 	/* Initialize */
1738 	if (destp == NULL) {
1739 		TRAP_ERROR();
1740 		return EINVAL;
1741 	}
1742 	*destp = NULL;
1743 
1744 	/* Make a writable copy of address for ng_path_parse() */
1745 	strncpy(fullpath, address, sizeof(fullpath) - 1);
1746 	fullpath[sizeof(fullpath) - 1] = '\0';
1747 
1748 	/* Parse out node and sequence of hooks */
1749 	if (ng_path_parse(fullpath, &nodename, &path, NULL) < 0) {
1750 		TRAP_ERROR();
1751 		return EINVAL;
1752 	}
1753 
1754 	/*
1755 	 * For an absolute address, jump to the starting node.
1756 	 * Note that this holds a reference on the node for us.
1757 	 * Don't forget to drop the reference if we don't need it.
1758 	 */
1759 	if (nodename) {
1760 		node = ng_name2noderef(here, nodename);
1761 		if (node == NULL) {
1762 			TRAP_ERROR();
1763 			return (ENOENT);
1764 		}
1765 	} else {
1766 		if (here == NULL) {
1767 			TRAP_ERROR();
1768 			return (EINVAL);
1769 		}
1770 		node = here;
1771 		NG_NODE_REF(node);
1772 	}
1773 
1774 	if (path == NULL) {
1775 		if (lasthook != NULL)
1776 			*lasthook = NULL;
1777 		*destp = node;
1778 		return (0);
1779 	}
1780 
1781 	/*
1782 	 * Now follow the sequence of hooks
1783 	 *
1784 	 * XXXGL: The path may demolish as we go the sequence, but if
1785 	 * we hold the topology mutex at critical places, then, I hope,
1786 	 * we would always have valid pointers in hand, although the
1787 	 * path behind us may no longer exist.
1788 	 */
1789 	for (;;) {
1790 		hook_p hook;
1791 		char *segment;
1792 
1793 		/*
1794 		 * Break out the next path segment. Replace the dot we just
1795 		 * found with a NUL; "path" points to the next segment (or the
1796 		 * NUL at the end).
1797 		 */
1798 		for (segment = path; *path != '\0'; path++) {
1799 			if (*path == '.') {
1800 				*path++ = '\0';
1801 				break;
1802 			}
1803 		}
1804 
1805 		/* We have a segment, so look for a hook by that name */
1806 		hook = ng_findhook(node, segment);
1807 
1808 		TOPOLOGY_WLOCK();
1809 		/* Can't get there from here... */
1810 		if (hook == NULL || NG_HOOK_PEER(hook) == NULL ||
1811 		    NG_HOOK_NOT_VALID(hook) ||
1812 		    NG_HOOK_NOT_VALID(NG_HOOK_PEER(hook))) {
1813 			TRAP_ERROR();
1814 			NG_NODE_UNREF(node);
1815 			TOPOLOGY_WUNLOCK();
1816 			return (ENOENT);
1817 		}
1818 
1819 		/*
1820 		 * Hop on over to the next node
1821 		 * XXX
1822 		 * Big race conditions here as hooks and nodes go away
1823 		 * *** Idea.. store an ng_ID_t in each hook and use that
1824 		 * instead of the direct hook in this crawl?
1825 		 */
1826 		oldnode = node;
1827 		if ((node = NG_PEER_NODE(hook)))
1828 			NG_NODE_REF(node);	/* XXX RACE */
1829 		NG_NODE_UNREF(oldnode);	/* XXX another race */
1830 		if (NG_NODE_NOT_VALID(node)) {
1831 			NG_NODE_UNREF(node);	/* XXX more races */
1832 			TOPOLOGY_WUNLOCK();
1833 			TRAP_ERROR();
1834 			return (ENXIO);
1835 		}
1836 
1837 		if (*path == '\0') {
1838 			if (lasthook != NULL) {
1839 				if (hook != NULL) {
1840 					*lasthook = NG_HOOK_PEER(hook);
1841 					NG_HOOK_REF(*lasthook);
1842 				} else
1843 					*lasthook = NULL;
1844 			}
1845 			TOPOLOGY_WUNLOCK();
1846 			*destp = node;
1847 			return (0);
1848 		}
1849 		TOPOLOGY_WUNLOCK();
1850 	}
1851 }
1852 
1853 /***************************************************************\
1854 * Input queue handling.
1855 * All activities are submitted to the node via the input queue
1856 * which implements a multiple-reader/single-writer gate.
1857 * Items which cannot be handled immediately are queued.
1858 *
1859 * read-write queue locking inline functions			*
1860 \***************************************************************/
1861 
1862 static __inline void	ng_queue_rw(node_p node, item_p  item, int rw);
1863 static __inline item_p	ng_dequeue(node_p node, int *rw);
1864 static __inline item_p	ng_acquire_read(node_p node, item_p  item);
1865 static __inline item_p	ng_acquire_write(node_p node, item_p  item);
1866 static __inline void	ng_leave_read(node_p node);
1867 static __inline void	ng_leave_write(node_p node);
1868 
1869 /*
1870  * Definition of the bits fields in the ng_queue flag word.
1871  * Defined here rather than in netgraph.h because no-one should fiddle
1872  * with them.
1873  *
1874  * The ordering here may be important! don't shuffle these.
1875  */
1876 /*-
1877  Safety Barrier--------+ (adjustable to suit taste) (not used yet)
1878                        |
1879                        V
1880 +-------+-------+-------+-------+-------+-------+-------+-------+
1881   | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
1882   | |A|c|t|i|v|e| |R|e|a|d|e|r| |C|o|u|n|t| | | | | | | | | |P|A|
1883   | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |O|W|
1884 +-------+-------+-------+-------+-------+-------+-------+-------+
1885   \___________________________ ____________________________/ | |
1886                             V                                | |
1887                   [active reader count]                      | |
1888                                                              | |
1889             Operation Pending -------------------------------+ |
1890                                                                |
1891           Active Writer ---------------------------------------+
1892 
1893 Node queue has such semantics:
1894 - All flags modifications are atomic.
1895 - Reader count can be incremented only if there is no writer or pending flags.
1896   As soon as this can't be done with single operation, it is implemented with
1897   spin loop and atomic_cmpset().
1898 - Writer flag can be set only if there is no any bits set.
1899   It is implemented with atomic_cmpset().
1900 - Pending flag can be set any time, but to avoid collision on queue processing
1901   all queue fields are protected by the mutex.
1902 - Queue processing thread reads queue holding the mutex, but releases it while
1903   processing. When queue is empty pending flag is removed.
1904 */
1905 
1906 #define WRITER_ACTIVE	0x00000001
1907 #define OP_PENDING	0x00000002
1908 #define READER_INCREMENT 0x00000004
1909 #define READER_MASK	0xfffffffc	/* Not valid if WRITER_ACTIVE is set */
1910 #define SAFETY_BARRIER	0x00100000	/* 128K items queued should be enough */
1911 
1912 /* Defines of more elaborate states on the queue */
1913 /* Mask of bits a new read cares about */
1914 #define NGQ_RMASK	(WRITER_ACTIVE|OP_PENDING)
1915 
1916 /* Mask of bits a new write cares about */
1917 #define NGQ_WMASK	(NGQ_RMASK|READER_MASK)
1918 
1919 /* Test to decide if there is something on the queue. */
1920 #define QUEUE_ACTIVE(QP) ((QP)->q_flags & OP_PENDING)
1921 
1922 /* How to decide what the next queued item is. */
1923 #define HEAD_IS_READER(QP)  NGI_QUEUED_READER(STAILQ_FIRST(&(QP)->queue))
1924 #define HEAD_IS_WRITER(QP)  NGI_QUEUED_WRITER(STAILQ_FIRST(&(QP)->queue)) /* notused */
1925 
1926 /* Read the status to decide if the next item on the queue can now run. */
1927 #define QUEUED_READER_CAN_PROCEED(QP)			\
1928 		(((QP)->q_flags & (NGQ_RMASK & ~OP_PENDING)) == 0)
1929 #define QUEUED_WRITER_CAN_PROCEED(QP)			\
1930 		(((QP)->q_flags & (NGQ_WMASK & ~OP_PENDING)) == 0)
1931 
1932 /* Is there a chance of getting ANY work off the queue? */
1933 #define NEXT_QUEUED_ITEM_CAN_PROCEED(QP)				\
1934 	((HEAD_IS_READER(QP)) ? QUEUED_READER_CAN_PROCEED(QP) :		\
1935 				QUEUED_WRITER_CAN_PROCEED(QP))
1936 
1937 #define NGQRW_R 0
1938 #define NGQRW_W 1
1939 
1940 #define NGQ2_WORKQ	0x00000001
1941 
1942 /*
1943  * Taking into account the current state of the queue and node, possibly take
1944  * the next entry off the queue and return it. Return NULL if there was
1945  * nothing we could return, either because there really was nothing there, or
1946  * because the node was in a state where it cannot yet process the next item
1947  * on the queue.
1948  */
1949 static __inline item_p
1950 ng_dequeue(node_p node, int *rw)
1951 {
1952 	item_p item;
1953 	struct ng_queue *ngq = &node->nd_input_queue;
1954 
1955 	/* This MUST be called with the mutex held. */
1956 	mtx_assert(&ngq->q_mtx, MA_OWNED);
1957 
1958 	/* If there is nothing queued, then just return. */
1959 	if (!QUEUE_ACTIVE(ngq)) {
1960 		CTR4(KTR_NET, "%20s: node [%x] (%p) queue empty; "
1961 		    "queue flags 0x%lx", __func__,
1962 		    node->nd_ID, node, ngq->q_flags);
1963 		return (NULL);
1964 	}
1965 
1966 	/*
1967 	 * From here, we can assume there is a head item.
1968 	 * We need to find out what it is and if it can be dequeued, given
1969 	 * the current state of the node.
1970 	 */
1971 	if (HEAD_IS_READER(ngq)) {
1972 		while (1) {
1973 			long t = ngq->q_flags;
1974 			if (t & WRITER_ACTIVE) {
1975 				/* There is writer, reader can't proceed. */
1976 				CTR4(KTR_NET, "%20s: node [%x] (%p) queued "
1977 				    "reader can't proceed; queue flags 0x%lx",
1978 				    __func__, node->nd_ID, node, t);
1979 				return (NULL);
1980 			}
1981 			if (atomic_cmpset_acq_int(&ngq->q_flags, t,
1982 			    t + READER_INCREMENT))
1983 				break;
1984 			cpu_spinwait();
1985 		}
1986 		/* We have got reader lock for the node. */
1987 		*rw = NGQRW_R;
1988 	} else if (atomic_cmpset_acq_int(&ngq->q_flags, OP_PENDING,
1989 	    OP_PENDING + WRITER_ACTIVE)) {
1990 		/* We have got writer lock for the node. */
1991 		*rw = NGQRW_W;
1992 	} else {
1993 		/* There is somebody other, writer can't proceed. */
1994 		CTR4(KTR_NET, "%20s: node [%x] (%p) queued writer can't "
1995 		    "proceed; queue flags 0x%lx", __func__, node->nd_ID, node,
1996 		    ngq->q_flags);
1997 		return (NULL);
1998 	}
1999 
2000 	/*
2001 	 * Now we dequeue the request (whatever it may be) and correct the
2002 	 * pending flags and the next and last pointers.
2003 	 */
2004 	item = STAILQ_FIRST(&ngq->queue);
2005 	STAILQ_REMOVE_HEAD(&ngq->queue, el_next);
2006 	if (STAILQ_EMPTY(&ngq->queue))
2007 		atomic_clear_int(&ngq->q_flags, OP_PENDING);
2008 	CTR6(KTR_NET, "%20s: node [%x] (%p) returning item %p as %s; queue "
2009 	    "flags 0x%lx", __func__, node->nd_ID, node, item, *rw ? "WRITER" :
2010 	    "READER", ngq->q_flags);
2011 	return (item);
2012 }
2013 
2014 /*
2015  * Queue a packet to be picked up later by someone else.
2016  * If the queue could be run now, add node to the queue handler's worklist.
2017  */
2018 static __inline void
2019 ng_queue_rw(node_p node, item_p  item, int rw)
2020 {
2021 	struct ng_queue *ngq = &node->nd_input_queue;
2022 	if (rw == NGQRW_W)
2023 		NGI_SET_WRITER(item);
2024 	else
2025 		NGI_SET_READER(item);
2026 	item->depth = 1;
2027 
2028 	NG_QUEUE_LOCK(ngq);
2029 	/* Set OP_PENDING flag and enqueue the item. */
2030 	atomic_set_int(&ngq->q_flags, OP_PENDING);
2031 	STAILQ_INSERT_TAIL(&ngq->queue, item, el_next);
2032 
2033 	CTR5(KTR_NET, "%20s: node [%x] (%p) queued item %p as %s", __func__,
2034 	    node->nd_ID, node, item, rw ? "WRITER" : "READER" );
2035 
2036 	/*
2037 	 * We can take the worklist lock with the node locked
2038 	 * BUT NOT THE REVERSE!
2039 	 */
2040 	if (NEXT_QUEUED_ITEM_CAN_PROCEED(ngq))
2041 		ng_worklist_add(node);
2042 	NG_QUEUE_UNLOCK(ngq);
2043 }
2044 
2045 /* Acquire reader lock on node. If node is busy, queue the packet. */
2046 static __inline item_p
2047 ng_acquire_read(node_p node, item_p item)
2048 {
2049 	KASSERT(node != &ng_deadnode,
2050 	    ("%s: working on deadnode", __func__));
2051 
2052 	/* Reader needs node without writer and pending items. */
2053 	for (;;) {
2054 		long t = node->nd_input_queue.q_flags;
2055 		if (t & NGQ_RMASK)
2056 			break; /* Node is not ready for reader. */
2057 		if (atomic_cmpset_acq_int(&node->nd_input_queue.q_flags, t,
2058 		    t + READER_INCREMENT)) {
2059 	    		/* Successfully grabbed node */
2060 			CTR4(KTR_NET, "%20s: node [%x] (%p) acquired item %p",
2061 			    __func__, node->nd_ID, node, item);
2062 			return (item);
2063 		}
2064 		cpu_spinwait();
2065 	}
2066 
2067 	/* Queue the request for later. */
2068 	ng_queue_rw(node, item, NGQRW_R);
2069 
2070 	return (NULL);
2071 }
2072 
2073 /* Acquire writer lock on node. If node is busy, queue the packet. */
2074 static __inline item_p
2075 ng_acquire_write(node_p node, item_p item)
2076 {
2077 	KASSERT(node != &ng_deadnode,
2078 	    ("%s: working on deadnode", __func__));
2079 
2080 	/* Writer needs completely idle node. */
2081 	if (atomic_cmpset_acq_int(&node->nd_input_queue.q_flags, 0,
2082 	    WRITER_ACTIVE)) {
2083 	    	/* Successfully grabbed node */
2084 		CTR4(KTR_NET, "%20s: node [%x] (%p) acquired item %p",
2085 		    __func__, node->nd_ID, node, item);
2086 		return (item);
2087 	}
2088 
2089 	/* Queue the request for later. */
2090 	ng_queue_rw(node, item, NGQRW_W);
2091 
2092 	return (NULL);
2093 }
2094 
2095 #if 0
2096 static __inline item_p
2097 ng_upgrade_write(node_p node, item_p item)
2098 {
2099 	struct ng_queue *ngq = &node->nd_input_queue;
2100 	KASSERT(node != &ng_deadnode,
2101 	    ("%s: working on deadnode", __func__));
2102 
2103 	NGI_SET_WRITER(item);
2104 
2105 	NG_QUEUE_LOCK(ngq);
2106 
2107 	/*
2108 	 * There will never be no readers as we are there ourselves.
2109 	 * Set the WRITER_ACTIVE flags ASAP to block out fast track readers.
2110 	 * The caller we are running from will call ng_leave_read()
2111 	 * soon, so we must account for that. We must leave again with the
2112 	 * READER lock. If we find other readers, then
2113 	 * queue the request for later. However "later" may be rignt now
2114 	 * if there are no readers. We don't really care if there are queued
2115 	 * items as we will bypass them anyhow.
2116 	 */
2117 	atomic_add_int(&ngq->q_flags, WRITER_ACTIVE - READER_INCREMENT);
2118 	if ((ngq->q_flags & (NGQ_WMASK & ~OP_PENDING)) == WRITER_ACTIVE) {
2119 		NG_QUEUE_UNLOCK(ngq);
2120 
2121 		/* It's just us, act on the item. */
2122 		/* will NOT drop writer lock when done */
2123 		ng_apply_item(node, item, 0);
2124 
2125 		/*
2126 		 * Having acted on the item, atomically
2127 		 * downgrade back to READER and finish up.
2128 	 	 */
2129 		atomic_add_int(&ngq->q_flags, READER_INCREMENT - WRITER_ACTIVE);
2130 
2131 		/* Our caller will call ng_leave_read() */
2132 		return;
2133 	}
2134 	/*
2135 	 * It's not just us active, so queue us AT THE HEAD.
2136 	 * "Why?" I hear you ask.
2137 	 * Put us at the head of the queue as we've already been
2138 	 * through it once. If there is nothing else waiting,
2139 	 * set the correct flags.
2140 	 */
2141 	if (STAILQ_EMPTY(&ngq->queue)) {
2142 		/* We've gone from, 0 to 1 item in the queue */
2143 		atomic_set_int(&ngq->q_flags, OP_PENDING);
2144 
2145 		CTR3(KTR_NET, "%20s: node [%x] (%p) set OP_PENDING", __func__,
2146 		    node->nd_ID, node);
2147 	};
2148 	STAILQ_INSERT_HEAD(&ngq->queue, item, el_next);
2149 	CTR4(KTR_NET, "%20s: node [%x] (%p) requeued item %p as WRITER",
2150 	    __func__, node->nd_ID, node, item );
2151 
2152 	/* Reverse what we did above. That downgrades us back to reader */
2153 	atomic_add_int(&ngq->q_flags, READER_INCREMENT - WRITER_ACTIVE);
2154 	if (QUEUE_ACTIVE(ngq) && NEXT_QUEUED_ITEM_CAN_PROCEED(ngq))
2155 		ng_worklist_add(node);
2156 	NG_QUEUE_UNLOCK(ngq);
2157 
2158 	return;
2159 }
2160 #endif
2161 
2162 /* Release reader lock. */
2163 static __inline void
2164 ng_leave_read(node_p node)
2165 {
2166 	atomic_subtract_rel_int(&node->nd_input_queue.q_flags, READER_INCREMENT);
2167 }
2168 
2169 /* Release writer lock. */
2170 static __inline void
2171 ng_leave_write(node_p node)
2172 {
2173 	atomic_clear_rel_int(&node->nd_input_queue.q_flags, WRITER_ACTIVE);
2174 }
2175 
2176 /* Purge node queue. Called on node shutdown. */
2177 static void
2178 ng_flush_input_queue(node_p node)
2179 {
2180 	struct ng_queue *ngq = &node->nd_input_queue;
2181 	item_p item;
2182 
2183 	NG_QUEUE_LOCK(ngq);
2184 	while ((item = STAILQ_FIRST(&ngq->queue)) != NULL) {
2185 		STAILQ_REMOVE_HEAD(&ngq->queue, el_next);
2186 		if (STAILQ_EMPTY(&ngq->queue))
2187 			atomic_clear_int(&ngq->q_flags, OP_PENDING);
2188 		NG_QUEUE_UNLOCK(ngq);
2189 
2190 		/* If the item is supplying a callback, call it with an error */
2191 		if (item->apply != NULL) {
2192 			if (item->depth == 1)
2193 				item->apply->error = ENOENT;
2194 			if (refcount_release(&item->apply->refs)) {
2195 				(*item->apply->apply)(item->apply->context,
2196 				    item->apply->error);
2197 			}
2198 		}
2199 		NG_FREE_ITEM(item);
2200 		NG_QUEUE_LOCK(ngq);
2201 	}
2202 	NG_QUEUE_UNLOCK(ngq);
2203 }
2204 
2205 /***********************************************************************
2206 * Externally visible method for sending or queueing messages or data.
2207 ***********************************************************************/
2208 
2209 /*
2210  * The module code should have filled out the item correctly by this stage:
2211  * Common:
2212  *    reference to destination node.
2213  *    Reference to destination rcv hook if relevant.
2214  *    apply pointer must be or NULL or reference valid struct ng_apply_info.
2215  * Data:
2216  *    pointer to mbuf
2217  * Control_Message:
2218  *    pointer to msg.
2219  *    ID of original sender node. (return address)
2220  * Function:
2221  *    Function pointer
2222  *    void * argument
2223  *    integer argument
2224  *
2225  * The nodes have several routines and macros to help with this task:
2226  */
2227 
2228 int
2229 ng_snd_item(item_p item, int flags)
2230 {
2231 	hook_p hook;
2232 	node_p node;
2233 	int queue, rw;
2234 	struct ng_queue *ngq;
2235 	int error = 0;
2236 
2237 	/* We are sending item, so it must be present! */
2238 	KASSERT(item != NULL, ("ng_snd_item: item is NULL"));
2239 
2240 #ifdef	NETGRAPH_DEBUG
2241 	_ngi_check(item, __FILE__, __LINE__);
2242 #endif
2243 
2244 	/* Item was sent once more, postpone apply() call. */
2245 	if (item->apply)
2246 		refcount_acquire(&item->apply->refs);
2247 
2248 	node = NGI_NODE(item);
2249 	/* Node is never optional. */
2250 	KASSERT(node != NULL, ("ng_snd_item: node is NULL"));
2251 
2252 	hook = NGI_HOOK(item);
2253 	/* Valid hook and mbuf are mandatory for data. */
2254 	if ((item->el_flags & NGQF_TYPE) == NGQF_DATA) {
2255 		KASSERT(hook != NULL, ("ng_snd_item: hook for data is NULL"));
2256 		if (NGI_M(item) == NULL)
2257 			ERROUT(EINVAL);
2258 		CHECK_DATA_MBUF(NGI_M(item));
2259 	}
2260 
2261 	/*
2262 	 * If the item or the node specifies single threading, force
2263 	 * writer semantics. Similarly, the node may say one hook always
2264 	 * produces writers. These are overrides.
2265 	 */
2266 	if (((item->el_flags & NGQF_RW) == NGQF_WRITER) ||
2267 	    (node->nd_flags & NGF_FORCE_WRITER) ||
2268 	    (hook && (hook->hk_flags & HK_FORCE_WRITER))) {
2269 		rw = NGQRW_W;
2270 	} else {
2271 		rw = NGQRW_R;
2272 	}
2273 
2274 	/*
2275 	 * If sender or receiver requests queued delivery, or call graph
2276 	 * loops back from outbound to inbound path, or stack usage
2277 	 * level is dangerous - enqueue message.
2278 	 */
2279 	if ((flags & NG_QUEUE) || (hook && (hook->hk_flags & HK_QUEUE))) {
2280 		queue = 1;
2281 	} else if (hook && (hook->hk_flags & HK_TO_INBOUND) &&
2282 	    curthread->td_ng_outbound) {
2283 		queue = 1;
2284 	} else {
2285 		queue = 0;
2286 
2287 		/*
2288 		 * Most of netgraph nodes have small stack consumption and
2289 		 * for them 25% of free stack space is more than enough.
2290 		 * Nodes/hooks with higher stack usage should be marked as
2291 		 * HI_STACK. For them 50% of stack will be guaranteed then.
2292 		 * XXX: Values 25% and 50% are completely empirical.
2293 		 */
2294 		size_t	st, su, sl;
2295 		GET_STACK_USAGE(st, su);
2296 		sl = st - su;
2297 		if ((sl * 4 < st) || ((sl * 2 < st) &&
2298 		    ((node->nd_flags & NGF_HI_STACK) || (hook &&
2299 		    (hook->hk_flags & HK_HI_STACK)))))
2300 			queue = 1;
2301 	}
2302 
2303 	if (queue) {
2304 		/* Put it on the queue for that node*/
2305 		ng_queue_rw(node, item, rw);
2306 		return ((flags & NG_PROGRESS) ? EINPROGRESS : 0);
2307 	}
2308 
2309 	/*
2310 	 * We already decided how we will be queueud or treated.
2311 	 * Try get the appropriate operating permission.
2312 	 */
2313  	if (rw == NGQRW_R)
2314 		item = ng_acquire_read(node, item);
2315 	else
2316 		item = ng_acquire_write(node, item);
2317 
2318 	/* Item was queued while trying to get permission. */
2319 	if (item == NULL)
2320 		return ((flags & NG_PROGRESS) ? EINPROGRESS : 0);
2321 
2322 	NGI_GET_NODE(item, node); /* zaps stored node */
2323 
2324 	item->depth++;
2325 	error = ng_apply_item(node, item, rw); /* drops r/w lock when done */
2326 
2327 	/* If something is waiting on queue and ready, schedule it. */
2328 	ngq = &node->nd_input_queue;
2329 	if (QUEUE_ACTIVE(ngq)) {
2330 		NG_QUEUE_LOCK(ngq);
2331 		if (QUEUE_ACTIVE(ngq) && NEXT_QUEUED_ITEM_CAN_PROCEED(ngq))
2332 			ng_worklist_add(node);
2333 		NG_QUEUE_UNLOCK(ngq);
2334 	}
2335 
2336 	/*
2337 	 * Node may go away as soon as we remove the reference.
2338 	 * Whatever we do, DO NOT access the node again!
2339 	 */
2340 	NG_NODE_UNREF(node);
2341 
2342 	return (error);
2343 
2344 done:
2345 	/* If was not sent, apply callback here. */
2346 	if (item->apply != NULL) {
2347 		if (item->depth == 0 && error != 0)
2348 			item->apply->error = error;
2349 		if (refcount_release(&item->apply->refs)) {
2350 			(*item->apply->apply)(item->apply->context,
2351 			    item->apply->error);
2352 		}
2353 	}
2354 
2355 	NG_FREE_ITEM(item);
2356 	return (error);
2357 }
2358 
2359 /*
2360  * We have an item that was possibly queued somewhere.
2361  * It should contain all the information needed
2362  * to run it on the appropriate node/hook.
2363  * If there is apply pointer and we own the last reference, call apply().
2364  */
2365 static int
2366 ng_apply_item(node_p node, item_p item, int rw)
2367 {
2368 	hook_p  hook;
2369 	ng_rcvdata_t *rcvdata;
2370 	ng_rcvmsg_t *rcvmsg;
2371 	struct ng_apply_info *apply;
2372 	int	error = 0, depth;
2373 
2374 	/* Node and item are never optional. */
2375 	KASSERT(node != NULL, ("ng_apply_item: node is NULL"));
2376 	KASSERT(item != NULL, ("ng_apply_item: item is NULL"));
2377 
2378 	NGI_GET_HOOK(item, hook); /* clears stored hook */
2379 #ifdef	NETGRAPH_DEBUG
2380 	_ngi_check(item, __FILE__, __LINE__);
2381 #endif
2382 
2383 	apply = item->apply;
2384 	depth = item->depth;
2385 
2386 	switch (item->el_flags & NGQF_TYPE) {
2387 	case NGQF_DATA:
2388 		/*
2389 		 * Check things are still ok as when we were queued.
2390 		 */
2391 		KASSERT(hook != NULL, ("ng_apply_item: hook for data is NULL"));
2392 		if (NG_HOOK_NOT_VALID(hook) ||
2393 		    NG_NODE_NOT_VALID(node)) {
2394 			error = EIO;
2395 			NG_FREE_ITEM(item);
2396 			break;
2397 		}
2398 		/*
2399 		 * If no receive method, just silently drop it.
2400 		 * Give preference to the hook over-ride method.
2401 		 */
2402 		if ((!(rcvdata = hook->hk_rcvdata)) &&
2403 		    (!(rcvdata = NG_HOOK_NODE(hook)->nd_type->rcvdata))) {
2404 			error = 0;
2405 			NG_FREE_ITEM(item);
2406 			break;
2407 		}
2408 		error = (*rcvdata)(hook, item);
2409 		break;
2410 	case NGQF_MESG:
2411 		if (hook && NG_HOOK_NOT_VALID(hook)) {
2412 			/*
2413 			 * The hook has been zapped then we can't use it.
2414 			 * Immediately drop its reference.
2415 			 * The message may not need it.
2416 			 */
2417 			NG_HOOK_UNREF(hook);
2418 			hook = NULL;
2419 		}
2420 		/*
2421 		 * Similarly, if the node is a zombie there is
2422 		 * nothing we can do with it, drop everything.
2423 		 */
2424 		if (NG_NODE_NOT_VALID(node)) {
2425 			TRAP_ERROR();
2426 			error = EINVAL;
2427 			NG_FREE_ITEM(item);
2428 			break;
2429 		}
2430 		/*
2431 		 * Call the appropriate message handler for the object.
2432 		 * It is up to the message handler to free the message.
2433 		 * If it's a generic message, handle it generically,
2434 		 * otherwise call the type's message handler (if it exists).
2435 		 * XXX (race). Remember that a queued message may
2436 		 * reference a node or hook that has just been
2437 		 * invalidated. It will exist as the queue code
2438 		 * is holding a reference, but..
2439 		 */
2440 		if ((NGI_MSG(item)->header.typecookie == NGM_GENERIC_COOKIE) &&
2441 		    ((NGI_MSG(item)->header.flags & NGF_RESP) == 0)) {
2442 			error = ng_generic_msg(node, item, hook);
2443 			break;
2444 		}
2445 		if (((!hook) || (!(rcvmsg = hook->hk_rcvmsg))) &&
2446 		    (!(rcvmsg = node->nd_type->rcvmsg))) {
2447 			TRAP_ERROR();
2448 			error = 0;
2449 			NG_FREE_ITEM(item);
2450 			break;
2451 		}
2452 		error = (*rcvmsg)(node, item, hook);
2453 		break;
2454 	case NGQF_FN:
2455 	case NGQF_FN2:
2456 		/*
2457 		 * In the case of the shutdown message we allow it to hit
2458 		 * even if the node is invalid.
2459 		 */
2460 		if (NG_NODE_NOT_VALID(node) &&
2461 		    NGI_FN(item) != &ng_rmnode) {
2462 			TRAP_ERROR();
2463 			error = EINVAL;
2464 			NG_FREE_ITEM(item);
2465 			break;
2466 		}
2467 		/* Same is about some internal functions and invalid hook. */
2468 		if (hook && NG_HOOK_NOT_VALID(hook) &&
2469 		    NGI_FN2(item) != &ng_con_part2 &&
2470 		    NGI_FN2(item) != &ng_con_part3 &&
2471 		    NGI_FN(item) != &ng_rmhook_part2) {
2472 			TRAP_ERROR();
2473 			error = EINVAL;
2474 			NG_FREE_ITEM(item);
2475 			break;
2476 		}
2477 
2478 		if ((item->el_flags & NGQF_TYPE) == NGQF_FN) {
2479 			(*NGI_FN(item))(node, hook, NGI_ARG1(item),
2480 			    NGI_ARG2(item));
2481 			NG_FREE_ITEM(item);
2482 		} else	/* it is NGQF_FN2 */
2483 			error = (*NGI_FN2(item))(node, item, hook);
2484 		break;
2485 	}
2486 	/*
2487 	 * We held references on some of the resources
2488 	 * that we took from the item. Now that we have
2489 	 * finished doing everything, drop those references.
2490 	 */
2491 	if (hook)
2492 		NG_HOOK_UNREF(hook);
2493 
2494  	if (rw == NGQRW_R)
2495 		ng_leave_read(node);
2496 	else
2497 		ng_leave_write(node);
2498 
2499 	/* Apply callback. */
2500 	if (apply != NULL) {
2501 		if (depth == 1 && error != 0)
2502 			apply->error = error;
2503 		if (refcount_release(&apply->refs))
2504 			(*apply->apply)(apply->context, apply->error);
2505 	}
2506 
2507 	return (error);
2508 }
2509 
2510 /***********************************************************************
2511  * Implement the 'generic' control messages
2512  ***********************************************************************/
2513 static int
2514 ng_generic_msg(node_p here, item_p item, hook_p lasthook)
2515 {
2516 	int error = 0;
2517 	struct ng_mesg *msg;
2518 	struct ng_mesg *resp = NULL;
2519 
2520 	NGI_GET_MSG(item, msg);
2521 	if (msg->header.typecookie != NGM_GENERIC_COOKIE) {
2522 		TRAP_ERROR();
2523 		error = EINVAL;
2524 		goto out;
2525 	}
2526 	switch (msg->header.cmd) {
2527 	case NGM_SHUTDOWN:
2528 		ng_rmnode(here, NULL, NULL, 0);
2529 		break;
2530 	case NGM_MKPEER:
2531 	    {
2532 		struct ngm_mkpeer *const mkp = (struct ngm_mkpeer *) msg->data;
2533 
2534 		if (msg->header.arglen != sizeof(*mkp)) {
2535 			TRAP_ERROR();
2536 			error = EINVAL;
2537 			break;
2538 		}
2539 		mkp->type[sizeof(mkp->type) - 1] = '\0';
2540 		mkp->ourhook[sizeof(mkp->ourhook) - 1] = '\0';
2541 		mkp->peerhook[sizeof(mkp->peerhook) - 1] = '\0';
2542 		error = ng_mkpeer(here, mkp->ourhook, mkp->peerhook, mkp->type);
2543 		break;
2544 	    }
2545 	case NGM_CONNECT:
2546 	    {
2547 		struct ngm_connect *const con =
2548 			(struct ngm_connect *) msg->data;
2549 		node_p node2;
2550 
2551 		if (msg->header.arglen != sizeof(*con)) {
2552 			TRAP_ERROR();
2553 			error = EINVAL;
2554 			break;
2555 		}
2556 		con->path[sizeof(con->path) - 1] = '\0';
2557 		con->ourhook[sizeof(con->ourhook) - 1] = '\0';
2558 		con->peerhook[sizeof(con->peerhook) - 1] = '\0';
2559 		/* Don't forget we get a reference.. */
2560 		error = ng_path2noderef(here, con->path, &node2, NULL);
2561 		if (error)
2562 			break;
2563 		error = ng_con_nodes(item, here, con->ourhook,
2564 		    node2, con->peerhook);
2565 		NG_NODE_UNREF(node2);
2566 		break;
2567 	    }
2568 	case NGM_NAME:
2569 	    {
2570 		struct ngm_name *const nam = (struct ngm_name *) msg->data;
2571 
2572 		if (msg->header.arglen != sizeof(*nam)) {
2573 			TRAP_ERROR();
2574 			error = EINVAL;
2575 			break;
2576 		}
2577 		nam->name[sizeof(nam->name) - 1] = '\0';
2578 		error = ng_name_node(here, nam->name);
2579 		break;
2580 	    }
2581 	case NGM_RMHOOK:
2582 	    {
2583 		struct ngm_rmhook *const rmh = (struct ngm_rmhook *) msg->data;
2584 		hook_p hook;
2585 
2586 		if (msg->header.arglen != sizeof(*rmh)) {
2587 			TRAP_ERROR();
2588 			error = EINVAL;
2589 			break;
2590 		}
2591 		rmh->ourhook[sizeof(rmh->ourhook) - 1] = '\0';
2592 		if ((hook = ng_findhook(here, rmh->ourhook)) != NULL)
2593 			ng_destroy_hook(hook);
2594 		break;
2595 	    }
2596 	case NGM_NODEINFO:
2597 	    {
2598 		struct nodeinfo *ni;
2599 
2600 		NG_MKRESPONSE(resp, msg, sizeof(*ni), M_NOWAIT);
2601 		if (resp == NULL) {
2602 			error = ENOMEM;
2603 			break;
2604 		}
2605 
2606 		/* Fill in node info */
2607 		ni = (struct nodeinfo *) resp->data;
2608 		if (NG_NODE_HAS_NAME(here))
2609 			strcpy(ni->name, NG_NODE_NAME(here));
2610 		strcpy(ni->type, here->nd_type->name);
2611 		ni->id = ng_node2ID(here);
2612 		ni->hooks = here->nd_numhooks;
2613 		break;
2614 	    }
2615 	case NGM_LISTHOOKS:
2616 	    {
2617 		const int nhooks = here->nd_numhooks;
2618 		struct hooklist *hl;
2619 		struct nodeinfo *ni;
2620 		hook_p hook;
2621 
2622 		/* Get response struct */
2623 		NG_MKRESPONSE(resp, msg, sizeof(*hl) +
2624 		    (nhooks * sizeof(struct linkinfo)), M_NOWAIT);
2625 		if (resp == NULL) {
2626 			error = ENOMEM;
2627 			break;
2628 		}
2629 		hl = (struct hooklist *) resp->data;
2630 		ni = &hl->nodeinfo;
2631 
2632 		/* Fill in node info */
2633 		if (NG_NODE_HAS_NAME(here))
2634 			strcpy(ni->name, NG_NODE_NAME(here));
2635 		strcpy(ni->type, here->nd_type->name);
2636 		ni->id = ng_node2ID(here);
2637 
2638 		/* Cycle through the linked list of hooks */
2639 		ni->hooks = 0;
2640 		LIST_FOREACH(hook, &here->nd_hooks, hk_hooks) {
2641 			struct linkinfo *const link = &hl->link[ni->hooks];
2642 
2643 			if (ni->hooks >= nhooks) {
2644 				log(LOG_ERR, "%s: number of %s changed\n",
2645 				    __func__, "hooks");
2646 				break;
2647 			}
2648 			if (NG_HOOK_NOT_VALID(hook))
2649 				continue;
2650 			strcpy(link->ourhook, NG_HOOK_NAME(hook));
2651 			strcpy(link->peerhook, NG_PEER_HOOK_NAME(hook));
2652 			if (NG_PEER_NODE_NAME(hook)[0] != '\0')
2653 				strcpy(link->nodeinfo.name,
2654 				    NG_PEER_NODE_NAME(hook));
2655 			strcpy(link->nodeinfo.type,
2656 			   NG_PEER_NODE(hook)->nd_type->name);
2657 			link->nodeinfo.id = ng_node2ID(NG_PEER_NODE(hook));
2658 			link->nodeinfo.hooks = NG_PEER_NODE(hook)->nd_numhooks;
2659 			ni->hooks++;
2660 		}
2661 		break;
2662 	    }
2663 
2664 	case NGM_LISTNODES:
2665 	    {
2666 		struct namelist *nl;
2667 		node_p node;
2668 		int i;
2669 
2670 		IDHASH_RLOCK();
2671 		/* Get response struct. */
2672 		NG_MKRESPONSE(resp, msg, sizeof(*nl) +
2673 		    (V_ng_nodes * sizeof(struct nodeinfo)), M_NOWAIT);
2674 		if (resp == NULL) {
2675 			IDHASH_RUNLOCK();
2676 			error = ENOMEM;
2677 			break;
2678 		}
2679 		nl = (struct namelist *) resp->data;
2680 
2681 		/* Cycle through the lists of nodes. */
2682 		nl->numnames = 0;
2683 		for (i = 0; i <= V_ng_ID_hmask; i++) {
2684 			LIST_FOREACH(node, &V_ng_ID_hash[i], nd_idnodes) {
2685 				struct nodeinfo *const np =
2686 				    &nl->nodeinfo[nl->numnames];
2687 
2688 				if (NG_NODE_NOT_VALID(node))
2689 					continue;
2690 				if (NG_NODE_HAS_NAME(node))
2691 					strcpy(np->name, NG_NODE_NAME(node));
2692 				strcpy(np->type, node->nd_type->name);
2693 				np->id = ng_node2ID(node);
2694 				np->hooks = node->nd_numhooks;
2695 				KASSERT(nl->numnames < V_ng_nodes,
2696 				    ("%s: no space", __func__));
2697 				nl->numnames++;
2698 			}
2699 		}
2700 		IDHASH_RUNLOCK();
2701 		break;
2702 	    }
2703 	case NGM_LISTNAMES:
2704 	    {
2705 		struct namelist *nl;
2706 		node_p node;
2707 		int i;
2708 
2709 		NAMEHASH_RLOCK();
2710 		/* Get response struct. */
2711 		NG_MKRESPONSE(resp, msg, sizeof(*nl) +
2712 		    (V_ng_named_nodes * sizeof(struct nodeinfo)), M_NOWAIT);
2713 		if (resp == NULL) {
2714 			NAMEHASH_RUNLOCK();
2715 			error = ENOMEM;
2716 			break;
2717 		}
2718 		nl = (struct namelist *) resp->data;
2719 
2720 		/* Cycle through the lists of nodes. */
2721 		nl->numnames = 0;
2722 		for (i = 0; i <= V_ng_name_hmask; i++) {
2723 			LIST_FOREACH(node, &V_ng_name_hash[i], nd_nodes) {
2724 				struct nodeinfo *const np =
2725 				    &nl->nodeinfo[nl->numnames];
2726 
2727 				if (NG_NODE_NOT_VALID(node))
2728 					continue;
2729 				strcpy(np->name, NG_NODE_NAME(node));
2730 				strcpy(np->type, node->nd_type->name);
2731 				np->id = ng_node2ID(node);
2732 				np->hooks = node->nd_numhooks;
2733 				KASSERT(nl->numnames < V_ng_named_nodes,
2734 				    ("%s: no space", __func__));
2735 				nl->numnames++;
2736 			}
2737 		}
2738 		NAMEHASH_RUNLOCK();
2739 		break;
2740 	    }
2741 
2742 	case NGM_LISTTYPES:
2743 	    {
2744 		struct typelist *tl;
2745 		struct ng_type *type;
2746 		int num = 0;
2747 
2748 		TYPELIST_RLOCK();
2749 		/* Count number of types */
2750 		LIST_FOREACH(type, &ng_typelist, types)
2751 			num++;
2752 
2753 		/* Get response struct */
2754 		NG_MKRESPONSE(resp, msg, sizeof(*tl) +
2755 		    (num * sizeof(struct typeinfo)), M_NOWAIT);
2756 		if (resp == NULL) {
2757 			TYPELIST_RUNLOCK();
2758 			error = ENOMEM;
2759 			break;
2760 		}
2761 		tl = (struct typelist *) resp->data;
2762 
2763 		/* Cycle through the linked list of types */
2764 		tl->numtypes = 0;
2765 		LIST_FOREACH(type, &ng_typelist, types) {
2766 			struct typeinfo *const tp = &tl->typeinfo[tl->numtypes];
2767 
2768 			strcpy(tp->type_name, type->name);
2769 			tp->numnodes = type->refs - 1; /* don't count list */
2770 			KASSERT(tl->numtypes < num, ("%s: no space", __func__));
2771 			tl->numtypes++;
2772 		}
2773 		TYPELIST_RUNLOCK();
2774 		break;
2775 	    }
2776 
2777 	case NGM_BINARY2ASCII:
2778 	    {
2779 		int bufSize = 1024;
2780 		const struct ng_parse_type *argstype;
2781 		const struct ng_cmdlist *c;
2782 		struct ng_mesg *binary, *ascii;
2783 
2784 		/* Data area must contain a valid netgraph message */
2785 		binary = (struct ng_mesg *)msg->data;
2786 		if (msg->header.arglen < sizeof(struct ng_mesg) ||
2787 		    (msg->header.arglen - sizeof(struct ng_mesg) <
2788 		    binary->header.arglen)) {
2789 			TRAP_ERROR();
2790 			error = EINVAL;
2791 			break;
2792 		}
2793 retry_b2a:
2794 		/* Get a response message with lots of room */
2795 		NG_MKRESPONSE(resp, msg, sizeof(*ascii) + bufSize, M_NOWAIT);
2796 		if (resp == NULL) {
2797 			error = ENOMEM;
2798 			break;
2799 		}
2800 		ascii = (struct ng_mesg *)resp->data;
2801 
2802 		/* Copy binary message header to response message payload */
2803 		bcopy(binary, ascii, sizeof(*binary));
2804 
2805 		/* Find command by matching typecookie and command number */
2806 		for (c = here->nd_type->cmdlist; c != NULL && c->name != NULL;
2807 		    c++) {
2808 			if (binary->header.typecookie == c->cookie &&
2809 			    binary->header.cmd == c->cmd)
2810 				break;
2811 		}
2812 		if (c == NULL || c->name == NULL) {
2813 			for (c = ng_generic_cmds; c->name != NULL; c++) {
2814 				if (binary->header.typecookie == c->cookie &&
2815 				    binary->header.cmd == c->cmd)
2816 					break;
2817 			}
2818 			if (c->name == NULL) {
2819 				NG_FREE_MSG(resp);
2820 				error = ENOSYS;
2821 				break;
2822 			}
2823 		}
2824 
2825 		/* Convert command name to ASCII */
2826 		snprintf(ascii->header.cmdstr, sizeof(ascii->header.cmdstr),
2827 		    "%s", c->name);
2828 
2829 		/* Convert command arguments to ASCII */
2830 		argstype = (binary->header.flags & NGF_RESP) ?
2831 		    c->respType : c->mesgType;
2832 		if (argstype == NULL) {
2833 			*ascii->data = '\0';
2834 		} else {
2835 			error = ng_unparse(argstype, (u_char *)binary->data,
2836 			    ascii->data, bufSize);
2837 			if (error == ERANGE) {
2838 				NG_FREE_MSG(resp);
2839 				bufSize *= 2;
2840 				goto retry_b2a;
2841 			} else if (error) {
2842 				NG_FREE_MSG(resp);
2843 				break;
2844 			}
2845 		}
2846 
2847 		/* Return the result as struct ng_mesg plus ASCII string */
2848 		bufSize = strlen(ascii->data) + 1;
2849 		ascii->header.arglen = bufSize;
2850 		resp->header.arglen = sizeof(*ascii) + bufSize;
2851 		break;
2852 	    }
2853 
2854 	case NGM_ASCII2BINARY:
2855 	    {
2856 		int bufSize = 20 * 1024;	/* XXX hard coded constant */
2857 		const struct ng_cmdlist *c;
2858 		const struct ng_parse_type *argstype;
2859 		struct ng_mesg *ascii, *binary;
2860 		int off = 0;
2861 
2862 		/* Data area must contain at least a struct ng_mesg + '\0' */
2863 		ascii = (struct ng_mesg *)msg->data;
2864 		if ((msg->header.arglen < sizeof(*ascii) + 1) ||
2865 		    (ascii->header.arglen < 1) ||
2866 		    (msg->header.arglen < sizeof(*ascii) +
2867 		    ascii->header.arglen)) {
2868 			TRAP_ERROR();
2869 			error = EINVAL;
2870 			break;
2871 		}
2872 		ascii->data[ascii->header.arglen - 1] = '\0';
2873 
2874 		/* Get a response message with lots of room */
2875 		NG_MKRESPONSE(resp, msg, sizeof(*binary) + bufSize, M_NOWAIT);
2876 		if (resp == NULL) {
2877 			error = ENOMEM;
2878 			break;
2879 		}
2880 		binary = (struct ng_mesg *)resp->data;
2881 
2882 		/* Copy ASCII message header to response message payload */
2883 		bcopy(ascii, binary, sizeof(*ascii));
2884 
2885 		/* Find command by matching ASCII command string */
2886 		for (c = here->nd_type->cmdlist;
2887 		    c != NULL && c->name != NULL; c++) {
2888 			if (strcmp(ascii->header.cmdstr, c->name) == 0)
2889 				break;
2890 		}
2891 		if (c == NULL || c->name == NULL) {
2892 			for (c = ng_generic_cmds; c->name != NULL; c++) {
2893 				if (strcmp(ascii->header.cmdstr, c->name) == 0)
2894 					break;
2895 			}
2896 			if (c->name == NULL) {
2897 				NG_FREE_MSG(resp);
2898 				error = ENOSYS;
2899 				break;
2900 			}
2901 		}
2902 
2903 		/* Convert command name to binary */
2904 		binary->header.cmd = c->cmd;
2905 		binary->header.typecookie = c->cookie;
2906 
2907 		/* Convert command arguments to binary */
2908 		argstype = (binary->header.flags & NGF_RESP) ?
2909 		    c->respType : c->mesgType;
2910 		if (argstype == NULL) {
2911 			bufSize = 0;
2912 		} else {
2913 			if ((error = ng_parse(argstype, ascii->data, &off,
2914 			    (u_char *)binary->data, &bufSize)) != 0) {
2915 				NG_FREE_MSG(resp);
2916 				break;
2917 			}
2918 		}
2919 
2920 		/* Return the result */
2921 		binary->header.arglen = bufSize;
2922 		resp->header.arglen = sizeof(*binary) + bufSize;
2923 		break;
2924 	    }
2925 
2926 	case NGM_TEXT_CONFIG:
2927 	case NGM_TEXT_STATUS:
2928 		/*
2929 		 * This one is tricky as it passes the command down to the
2930 		 * actual node, even though it is a generic type command.
2931 		 * This means we must assume that the item/msg is already freed
2932 		 * when control passes back to us.
2933 		 */
2934 		if (here->nd_type->rcvmsg != NULL) {
2935 			NGI_MSG(item) = msg; /* put it back as we found it */
2936 			return((*here->nd_type->rcvmsg)(here, item, lasthook));
2937 		}
2938 		/* Fall through if rcvmsg not supported */
2939 	default:
2940 		TRAP_ERROR();
2941 		error = EINVAL;
2942 	}
2943 	/*
2944 	 * Sometimes a generic message may be statically allocated
2945 	 * to avoid problems with allocating when in tight memory situations.
2946 	 * Don't free it if it is so.
2947 	 * I break them apart here, because erros may cause a free if the item
2948 	 * in which case we'd be doing it twice.
2949 	 * they are kept together above, to simplify freeing.
2950 	 */
2951 out:
2952 	NG_RESPOND_MSG(error, here, item, resp);
2953 	NG_FREE_MSG(msg);
2954 	return (error);
2955 }
2956 
2957 /************************************************************************
2958 			Queue element get/free routines
2959 ************************************************************************/
2960 
2961 uma_zone_t			ng_qzone;
2962 uma_zone_t			ng_qdzone;
2963 static int			numthreads = 0; /* number of queue threads */
2964 static int			maxalloc = 4096;/* limit the damage of a leak */
2965 static int			maxdata = 4096;	/* limit the damage of a DoS */
2966 
2967 SYSCTL_INT(_net_graph, OID_AUTO, threads, CTLFLAG_RDTUN, &numthreads,
2968     0, "Number of queue processing threads");
2969 SYSCTL_INT(_net_graph, OID_AUTO, maxalloc, CTLFLAG_RDTUN, &maxalloc,
2970     0, "Maximum number of non-data queue items to allocate");
2971 SYSCTL_INT(_net_graph, OID_AUTO, maxdata, CTLFLAG_RDTUN, &maxdata,
2972     0, "Maximum number of data queue items to allocate");
2973 
2974 #ifdef	NETGRAPH_DEBUG
2975 static TAILQ_HEAD(, ng_item) ng_itemlist = TAILQ_HEAD_INITIALIZER(ng_itemlist);
2976 static int allocated;	/* number of items malloc'd */
2977 #endif
2978 
2979 /*
2980  * Get a queue entry.
2981  * This is usually called when a packet first enters netgraph.
2982  * By definition, this is usually from an interrupt, or from a user.
2983  * Users are not so important, but try be quick for the times that it's
2984  * an interrupt.
2985  */
2986 static __inline item_p
2987 ng_alloc_item(int type, int flags)
2988 {
2989 	item_p item;
2990 
2991 	KASSERT(((type & ~NGQF_TYPE) == 0),
2992 	    ("%s: incorrect item type: %d", __func__, type));
2993 
2994 	item = uma_zalloc((type == NGQF_DATA) ? ng_qdzone : ng_qzone,
2995 	    ((flags & NG_WAITOK) ? M_WAITOK : M_NOWAIT) | M_ZERO);
2996 
2997 	if (item) {
2998 		item->el_flags = type;
2999 #ifdef	NETGRAPH_DEBUG
3000 		mtx_lock(&ngq_mtx);
3001 		TAILQ_INSERT_TAIL(&ng_itemlist, item, all);
3002 		allocated++;
3003 		mtx_unlock(&ngq_mtx);
3004 #endif
3005 	}
3006 
3007 	return (item);
3008 }
3009 
3010 /*
3011  * Release a queue entry
3012  */
3013 void
3014 ng_free_item(item_p item)
3015 {
3016 	/*
3017 	 * The item may hold resources on its own. We need to free
3018 	 * these before we can free the item. What they are depends upon
3019 	 * what kind of item it is. it is important that nodes zero
3020 	 * out pointers to resources that they remove from the item
3021 	 * or we release them again here.
3022 	 */
3023 	switch (item->el_flags & NGQF_TYPE) {
3024 	case NGQF_DATA:
3025 		/* If we have an mbuf still attached.. */
3026 		NG_FREE_M(_NGI_M(item));
3027 		break;
3028 	case NGQF_MESG:
3029 		_NGI_RETADDR(item) = 0;
3030 		NG_FREE_MSG(_NGI_MSG(item));
3031 		break;
3032 	case NGQF_FN:
3033 	case NGQF_FN2:
3034 		/* nothing to free really, */
3035 		_NGI_FN(item) = NULL;
3036 		_NGI_ARG1(item) = NULL;
3037 		_NGI_ARG2(item) = 0;
3038 		break;
3039 	}
3040 	/* If we still have a node or hook referenced... */
3041 	_NGI_CLR_NODE(item);
3042 	_NGI_CLR_HOOK(item);
3043 
3044 #ifdef	NETGRAPH_DEBUG
3045 	mtx_lock(&ngq_mtx);
3046 	TAILQ_REMOVE(&ng_itemlist, item, all);
3047 	allocated--;
3048 	mtx_unlock(&ngq_mtx);
3049 #endif
3050 	uma_zfree(((item->el_flags & NGQF_TYPE) == NGQF_DATA) ?
3051 	    ng_qdzone : ng_qzone, item);
3052 }
3053 
3054 /*
3055  * Change type of the queue entry.
3056  * Possibly reallocates it from another UMA zone.
3057  */
3058 static __inline item_p
3059 ng_realloc_item(item_p pitem, int type, int flags)
3060 {
3061 	item_p item;
3062 	int from, to;
3063 
3064 	KASSERT((pitem != NULL), ("%s: can't reallocate NULL", __func__));
3065 	KASSERT(((type & ~NGQF_TYPE) == 0),
3066 	    ("%s: incorrect item type: %d", __func__, type));
3067 
3068 	from = ((pitem->el_flags & NGQF_TYPE) == NGQF_DATA);
3069 	to = (type == NGQF_DATA);
3070 	if (from != to) {
3071 		/* If reallocation is required do it and copy item. */
3072 		if ((item = ng_alloc_item(type, flags)) == NULL) {
3073 			ng_free_item(pitem);
3074 			return (NULL);
3075 		}
3076 		*item = *pitem;
3077 		ng_free_item(pitem);
3078 	} else
3079 		item = pitem;
3080 	item->el_flags = (item->el_flags & ~NGQF_TYPE) | type;
3081 
3082 	return (item);
3083 }
3084 
3085 /************************************************************************
3086 			Module routines
3087 ************************************************************************/
3088 
3089 /*
3090  * Handle the loading/unloading of a netgraph node type module
3091  */
3092 int
3093 ng_mod_event(module_t mod, int event, void *data)
3094 {
3095 	struct ng_type *const type = data;
3096 	int error = 0;
3097 
3098 	switch (event) {
3099 	case MOD_LOAD:
3100 
3101 		/* Register new netgraph node type */
3102 		if ((error = ng_newtype(type)) != 0)
3103 			break;
3104 
3105 		/* Call type specific code */
3106 		if (type->mod_event != NULL)
3107 			if ((error = (*type->mod_event)(mod, event, data))) {
3108 				TYPELIST_WLOCK();
3109 				type->refs--;	/* undo it */
3110 				LIST_REMOVE(type, types);
3111 				TYPELIST_WUNLOCK();
3112 			}
3113 		break;
3114 
3115 	case MOD_UNLOAD:
3116 		if (type->refs > 1) {		/* make sure no nodes exist! */
3117 			error = EBUSY;
3118 		} else {
3119 			if (type->refs == 0) /* failed load, nothing to undo */
3120 				break;
3121 			if (type->mod_event != NULL) {	/* check with type */
3122 				error = (*type->mod_event)(mod, event, data);
3123 				if (error != 0)	/* type refuses.. */
3124 					break;
3125 			}
3126 			TYPELIST_WLOCK();
3127 			LIST_REMOVE(type, types);
3128 			TYPELIST_WUNLOCK();
3129 		}
3130 		break;
3131 
3132 	default:
3133 		if (type->mod_event != NULL)
3134 			error = (*type->mod_event)(mod, event, data);
3135 		else
3136 			error = EOPNOTSUPP;		/* XXX ? */
3137 		break;
3138 	}
3139 	return (error);
3140 }
3141 
3142 static void
3143 vnet_netgraph_init(const void *unused __unused)
3144 {
3145 
3146 	/* We start with small hashes, but they can grow. */
3147 	V_ng_ID_hash = hashinit(16, M_NETGRAPH_NODE, &V_ng_ID_hmask);
3148 	V_ng_name_hash = hashinit(16, M_NETGRAPH_NODE, &V_ng_name_hmask);
3149 }
3150 VNET_SYSINIT(vnet_netgraph_init, SI_SUB_NETGRAPH, SI_ORDER_FIRST,
3151     vnet_netgraph_init, NULL);
3152 
3153 #ifdef VIMAGE
3154 static void
3155 vnet_netgraph_uninit(const void *unused __unused)
3156 {
3157 	node_p node = NULL, last_killed = NULL;
3158 	int i;
3159 
3160 	do {
3161 		/* Find a node to kill */
3162 		IDHASH_RLOCK();
3163 		for (i = 0; i <= V_ng_ID_hmask; i++) {
3164 			LIST_FOREACH(node, &V_ng_ID_hash[i], nd_idnodes) {
3165 				if (node != &ng_deadnode) {
3166 					NG_NODE_REF(node);
3167 					break;
3168 				}
3169 			}
3170 			if (node != NULL)
3171 				break;
3172 		}
3173 		IDHASH_RUNLOCK();
3174 
3175 		/* Attempt to kill it only if it is a regular node */
3176 		if (node != NULL) {
3177 			if (node == last_killed) {
3178 				if (node->nd_flags & NGF_REALLY_DIE)
3179 					panic("ng node %s won't die",
3180 					    node->nd_name);
3181 				/* The node persisted itself.  Try again. */
3182 				node->nd_flags |= NGF_REALLY_DIE;
3183 			}
3184 			ng_rmnode(node, NULL, NULL, 0);
3185 			NG_NODE_UNREF(node);
3186 			last_killed = node;
3187 		}
3188 	} while (node != NULL);
3189 
3190 	hashdestroy(V_ng_name_hash, M_NETGRAPH_NODE, V_ng_name_hmask);
3191 	hashdestroy(V_ng_ID_hash, M_NETGRAPH_NODE, V_ng_ID_hmask);
3192 }
3193 VNET_SYSUNINIT(vnet_netgraph_uninit, SI_SUB_NETGRAPH, SI_ORDER_FIRST,
3194     vnet_netgraph_uninit, NULL);
3195 #endif /* VIMAGE */
3196 
3197 /*
3198  * Handle loading and unloading for this code.
3199  * The only thing we need to link into is the NETISR strucure.
3200  */
3201 static int
3202 ngb_mod_event(module_t mod, int event, void *data)
3203 {
3204 	struct proc *p;
3205 	struct thread *td;
3206 	int i, error = 0;
3207 
3208 	switch (event) {
3209 	case MOD_LOAD:
3210 		/* Initialize everything. */
3211 		NG_WORKLIST_LOCK_INIT();
3212 		rw_init(&ng_typelist_lock, "netgraph types");
3213 		rw_init(&ng_idhash_lock, "netgraph idhash");
3214 		rw_init(&ng_namehash_lock, "netgraph namehash");
3215 		rw_init(&ng_topo_lock, "netgraph topology mutex");
3216 #ifdef	NETGRAPH_DEBUG
3217 		mtx_init(&ng_nodelist_mtx, "netgraph nodelist mutex", NULL,
3218 		    MTX_DEF);
3219 		mtx_init(&ngq_mtx, "netgraph item list mutex", NULL,
3220 		    MTX_DEF);
3221 #endif
3222 		ng_qzone = uma_zcreate("NetGraph items", sizeof(struct ng_item),
3223 		    NULL, NULL, NULL, NULL, UMA_ALIGN_CACHE, 0);
3224 		uma_zone_set_max(ng_qzone, maxalloc);
3225 		ng_qdzone = uma_zcreate("NetGraph data items",
3226 		    sizeof(struct ng_item), NULL, NULL, NULL, NULL,
3227 		    UMA_ALIGN_CACHE, 0);
3228 		uma_zone_set_max(ng_qdzone, maxdata);
3229 		/* Autoconfigure number of threads. */
3230 		if (numthreads <= 0)
3231 			numthreads = mp_ncpus;
3232 		/* Create threads. */
3233     		p = NULL; /* start with no process */
3234 		for (i = 0; i < numthreads; i++) {
3235 			if (kproc_kthread_add(ngthread, NULL, &p, &td,
3236 			    RFHIGHPID, 0, "ng_queue", "ng_queue%d", i)) {
3237 				numthreads = i;
3238 				break;
3239 			}
3240 		}
3241 		break;
3242 	case MOD_UNLOAD:
3243 		/* You can't unload it because an interface may be using it. */
3244 		error = EBUSY;
3245 		break;
3246 	default:
3247 		error = EOPNOTSUPP;
3248 		break;
3249 	}
3250 	return (error);
3251 }
3252 
3253 static moduledata_t netgraph_mod = {
3254 	"netgraph",
3255 	ngb_mod_event,
3256 	(NULL)
3257 };
3258 DECLARE_MODULE(netgraph, netgraph_mod, SI_SUB_NETGRAPH, SI_ORDER_FIRST);
3259 SYSCTL_NODE(_net, OID_AUTO, graph, CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
3260     "netgraph Family");
3261 SYSCTL_INT(_net_graph, OID_AUTO, abi_version, CTLFLAG_RD, SYSCTL_NULL_INT_PTR, NG_ABI_VERSION,"");
3262 SYSCTL_INT(_net_graph, OID_AUTO, msg_version, CTLFLAG_RD, SYSCTL_NULL_INT_PTR, NG_VERSION, "");
3263 
3264 #ifdef	NETGRAPH_DEBUG
3265 void
3266 dumphook (hook_p hook, char *file, int line)
3267 {
3268 	printf("hook: name %s, %d refs, Last touched:\n",
3269 		_NG_HOOK_NAME(hook), hook->hk_refs);
3270 	printf("	Last active @ %s, line %d\n",
3271 		hook->lastfile, hook->lastline);
3272 	if (line) {
3273 		printf(" problem discovered at file %s, line %d\n", file, line);
3274 #ifdef KDB
3275 		kdb_backtrace();
3276 #endif
3277 	}
3278 }
3279 
3280 void
3281 dumpnode(node_p node, char *file, int line)
3282 {
3283 	printf("node: ID [%x]: type '%s', %d hooks, flags 0x%x, %d refs, %s:\n",
3284 		_NG_NODE_ID(node), node->nd_type->name,
3285 		node->nd_numhooks, node->nd_flags,
3286 		node->nd_refs, node->nd_name);
3287 	printf("	Last active @ %s, line %d\n",
3288 		node->lastfile, node->lastline);
3289 	if (line) {
3290 		printf(" problem discovered at file %s, line %d\n", file, line);
3291 #ifdef KDB
3292 		kdb_backtrace();
3293 #endif
3294 	}
3295 }
3296 
3297 void
3298 dumpitem(item_p item, char *file, int line)
3299 {
3300 	printf(" ACTIVE item, last used at %s, line %d",
3301 		item->lastfile, item->lastline);
3302 	switch(item->el_flags & NGQF_TYPE) {
3303 	case NGQF_DATA:
3304 		printf(" - [data]\n");
3305 		break;
3306 	case NGQF_MESG:
3307 		printf(" - retaddr[%d]:\n", _NGI_RETADDR(item));
3308 		break;
3309 	case NGQF_FN:
3310 		printf(" - fn@%p (%p, %p, %p, %d (%x))\n",
3311 			_NGI_FN(item),
3312 			_NGI_NODE(item),
3313 			_NGI_HOOK(item),
3314 			item->body.fn.fn_arg1,
3315 			item->body.fn.fn_arg2,
3316 			item->body.fn.fn_arg2);
3317 		break;
3318 	case NGQF_FN2:
3319 		printf(" - fn2@%p (%p, %p, %p, %d (%x))\n",
3320 			_NGI_FN2(item),
3321 			_NGI_NODE(item),
3322 			_NGI_HOOK(item),
3323 			item->body.fn.fn_arg1,
3324 			item->body.fn.fn_arg2,
3325 			item->body.fn.fn_arg2);
3326 		break;
3327 	}
3328 	if (line) {
3329 		printf(" problem discovered at file %s, line %d\n", file, line);
3330 		if (_NGI_NODE(item)) {
3331 			printf("node %p ([%x])\n",
3332 				_NGI_NODE(item), ng_node2ID(_NGI_NODE(item)));
3333 		}
3334 	}
3335 }
3336 
3337 static void
3338 ng_dumpitems(void)
3339 {
3340 	item_p item;
3341 	int i = 1;
3342 	TAILQ_FOREACH(item, &ng_itemlist, all) {
3343 		printf("[%d] ", i++);
3344 		dumpitem(item, NULL, 0);
3345 	}
3346 }
3347 
3348 static void
3349 ng_dumpnodes(void)
3350 {
3351 	node_p node;
3352 	int i = 1;
3353 	mtx_lock(&ng_nodelist_mtx);
3354 	SLIST_FOREACH(node, &ng_allnodes, nd_all) {
3355 		printf("[%d] ", i++);
3356 		dumpnode(node, NULL, 0);
3357 	}
3358 	mtx_unlock(&ng_nodelist_mtx);
3359 }
3360 
3361 static void
3362 ng_dumphooks(void)
3363 {
3364 	hook_p hook;
3365 	int i = 1;
3366 	mtx_lock(&ng_nodelist_mtx);
3367 	SLIST_FOREACH(hook, &ng_allhooks, hk_all) {
3368 		printf("[%d] ", i++);
3369 		dumphook(hook, NULL, 0);
3370 	}
3371 	mtx_unlock(&ng_nodelist_mtx);
3372 }
3373 
3374 static int
3375 sysctl_debug_ng_dump_items(SYSCTL_HANDLER_ARGS)
3376 {
3377 	int error;
3378 	int val;
3379 
3380 	val = allocated;
3381 	error = sysctl_handle_int(oidp, &val, 0, req);
3382 	if (error != 0 || req->newptr == NULL)
3383 		return (error);
3384 	if (val == 42) {
3385 		ng_dumpitems();
3386 		ng_dumpnodes();
3387 		ng_dumphooks();
3388 	}
3389 	return (0);
3390 }
3391 
3392 SYSCTL_PROC(_debug, OID_AUTO, ng_dump_items,
3393     CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_MPSAFE, 0, sizeof(int),
3394     sysctl_debug_ng_dump_items, "I",
3395     "Number of allocated items");
3396 #endif	/* NETGRAPH_DEBUG */
3397 
3398 /***********************************************************************
3399 * Worklist routines
3400 **********************************************************************/
3401 /*
3402  * Pick a node off the list of nodes with work,
3403  * try get an item to process off it. Remove the node from the list.
3404  */
3405 static void
3406 ngthread(void *arg)
3407 {
3408 	for (;;) {
3409 		struct epoch_tracker et;
3410 		node_p  node;
3411 
3412 		/* Get node from the worklist. */
3413 		NG_WORKLIST_LOCK();
3414 		while ((node = STAILQ_FIRST(&ng_worklist)) == NULL)
3415 			NG_WORKLIST_SLEEP();
3416 		STAILQ_REMOVE_HEAD(&ng_worklist, nd_input_queue.q_work);
3417 		NG_WORKLIST_UNLOCK();
3418 		CURVNET_SET(node->nd_vnet);
3419 		CTR3(KTR_NET, "%20s: node [%x] (%p) taken off worklist",
3420 		    __func__, node->nd_ID, node);
3421 		/*
3422 		 * We have the node. We also take over the reference
3423 		 * that the list had on it.
3424 		 * Now process as much as you can, until it won't
3425 		 * let you have another item off the queue.
3426 		 * All this time, keep the reference
3427 		 * that lets us be sure that the node still exists.
3428 		 * Let the reference go at the last minute.
3429 		 */
3430 		NET_EPOCH_ENTER(et);
3431 		for (;;) {
3432 			item_p item;
3433 			int rw;
3434 
3435 			NG_QUEUE_LOCK(&node->nd_input_queue);
3436 			item = ng_dequeue(node, &rw);
3437 			if (item == NULL) {
3438 				node->nd_input_queue.q_flags2 &= ~NGQ2_WORKQ;
3439 				NG_QUEUE_UNLOCK(&node->nd_input_queue);
3440 				break; /* go look for another node */
3441 			} else {
3442 				NG_QUEUE_UNLOCK(&node->nd_input_queue);
3443 				NGI_GET_NODE(item, node); /* zaps stored node */
3444 
3445 				if ((item->el_flags & NGQF_TYPE) == NGQF_MESG) {
3446 					/*
3447 					 * NGQF_MESG items should never be processed in
3448 					 * NET_EPOCH context. So, temporary exit from EPOCH.
3449 					 */
3450 					NET_EPOCH_EXIT(et);
3451 					ng_apply_item(node, item, rw);
3452 					NET_EPOCH_ENTER(et);
3453 				} else {
3454 					ng_apply_item(node, item, rw);
3455 				}
3456 
3457 				NG_NODE_UNREF(node);
3458 			}
3459 		}
3460 		NET_EPOCH_EXIT(et);
3461 		NG_NODE_UNREF(node);
3462 		CURVNET_RESTORE();
3463 	}
3464 }
3465 
3466 /*
3467  * XXX
3468  * It's possible that a debugging NG_NODE_REF may need
3469  * to be outside the mutex zone
3470  */
3471 static void
3472 ng_worklist_add(node_p node)
3473 {
3474 
3475 	mtx_assert(&node->nd_input_queue.q_mtx, MA_OWNED);
3476 
3477 	if ((node->nd_input_queue.q_flags2 & NGQ2_WORKQ) == 0) {
3478 		/*
3479 		 * If we are not already on the work queue,
3480 		 * then put us on.
3481 		 */
3482 		node->nd_input_queue.q_flags2 |= NGQ2_WORKQ;
3483 		NG_NODE_REF(node); /* XXX safe in mutex? */
3484 		NG_WORKLIST_LOCK();
3485 		STAILQ_INSERT_TAIL(&ng_worklist, node, nd_input_queue.q_work);
3486 		NG_WORKLIST_UNLOCK();
3487 		CTR3(KTR_NET, "%20s: node [%x] (%p) put on worklist", __func__,
3488 		    node->nd_ID, node);
3489 		NG_WORKLIST_WAKEUP();
3490 	} else {
3491 		CTR3(KTR_NET, "%20s: node [%x] (%p) already on worklist",
3492 		    __func__, node->nd_ID, node);
3493 	}
3494 }
3495 
3496 /***********************************************************************
3497 * Externally useable functions to set up a queue item ready for sending
3498 ***********************************************************************/
3499 
3500 #ifdef	NETGRAPH_DEBUG
3501 #define	ITEM_DEBUG_CHECKS						\
3502 	do {								\
3503 		if (NGI_NODE(item) ) {					\
3504 			printf("item already has node");		\
3505 			kdb_enter(KDB_WHY_NETGRAPH, "has node");	\
3506 			NGI_CLR_NODE(item);				\
3507 		}							\
3508 		if (NGI_HOOK(item) ) {					\
3509 			printf("item already has hook");		\
3510 			kdb_enter(KDB_WHY_NETGRAPH, "has hook");	\
3511 			NGI_CLR_HOOK(item);				\
3512 		}							\
3513 	} while (0)
3514 #else
3515 #define ITEM_DEBUG_CHECKS
3516 #endif
3517 
3518 /*
3519  * Put mbuf into the item.
3520  * Hook and node references will be removed when the item is dequeued.
3521  * (or equivalent)
3522  * (XXX) Unsafe because no reference held by peer on remote node.
3523  * remote node might go away in this timescale.
3524  * We know the hooks can't go away because that would require getting
3525  * a writer item on both nodes and we must have at least a  reader
3526  * here to be able to do this.
3527  * Note that the hook loaded is the REMOTE hook.
3528  *
3529  * This is possibly in the critical path for new data.
3530  */
3531 item_p
3532 ng_package_data(struct mbuf *m, int flags)
3533 {
3534 	item_p item;
3535 
3536 	if ((item = ng_alloc_item(NGQF_DATA, flags)) == NULL) {
3537 		NG_FREE_M(m);
3538 		return (NULL);
3539 	}
3540 	ITEM_DEBUG_CHECKS;
3541 	item->el_flags |= NGQF_READER;
3542 	NGI_M(item) = m;
3543 	return (item);
3544 }
3545 
3546 /*
3547  * Allocate a queue item and put items into it..
3548  * Evaluate the address as this will be needed to queue it and
3549  * to work out what some of the fields should be.
3550  * Hook and node references will be removed when the item is dequeued.
3551  * (or equivalent)
3552  */
3553 item_p
3554 ng_package_msg(struct ng_mesg *msg, int flags)
3555 {
3556 	item_p item;
3557 
3558 	if ((item = ng_alloc_item(NGQF_MESG, flags)) == NULL) {
3559 		NG_FREE_MSG(msg);
3560 		return (NULL);
3561 	}
3562 	ITEM_DEBUG_CHECKS;
3563 	/* Messages items count as writers unless explicitly exempted. */
3564 	if (msg->header.cmd & NGM_READONLY)
3565 		item->el_flags |= NGQF_READER;
3566 	else
3567 		item->el_flags |= NGQF_WRITER;
3568 	/*
3569 	 * Set the current lasthook into the queue item
3570 	 */
3571 	NGI_MSG(item) = msg;
3572 	NGI_RETADDR(item) = 0;
3573 	return (item);
3574 }
3575 
3576 #define SET_RETADDR(item, here, retaddr)				\
3577 	do {	/* Data or fn items don't have retaddrs */		\
3578 		if ((item->el_flags & NGQF_TYPE) == NGQF_MESG) {	\
3579 			if (retaddr) {					\
3580 				NGI_RETADDR(item) = retaddr;		\
3581 			} else {					\
3582 				/*					\
3583 				 * The old return address should be ok.	\
3584 				 * If there isn't one, use the address	\
3585 				 * here.				\
3586 				 */					\
3587 				if (NGI_RETADDR(item) == 0) {		\
3588 					NGI_RETADDR(item)		\
3589 						= ng_node2ID(here);	\
3590 				}					\
3591 			}						\
3592 		}							\
3593 	} while (0)
3594 
3595 int
3596 ng_address_hook(node_p here, item_p item, hook_p hook, ng_ID_t retaddr)
3597 {
3598 	hook_p peer;
3599 	node_p peernode;
3600 	ITEM_DEBUG_CHECKS;
3601 	/*
3602 	 * Quick sanity check..
3603 	 * Since a hook holds a reference on its node, once we know
3604 	 * that the peer is still connected (even if invalid,) we know
3605 	 * that the peer node is present, though maybe invalid.
3606 	 */
3607 	TOPOLOGY_RLOCK();
3608 	if ((hook == NULL) || NG_HOOK_NOT_VALID(hook) ||
3609 	    NG_HOOK_NOT_VALID(peer = NG_HOOK_PEER(hook)) ||
3610 	    NG_NODE_NOT_VALID(peernode = NG_PEER_NODE(hook))) {
3611 		NG_FREE_ITEM(item);
3612 		TRAP_ERROR();
3613 		TOPOLOGY_RUNLOCK();
3614 		return (ENETDOWN);
3615 	}
3616 
3617 	/*
3618 	 * Transfer our interest to the other (peer) end.
3619 	 */
3620 	NG_HOOK_REF(peer);
3621 	NG_NODE_REF(peernode);
3622 	NGI_SET_HOOK(item, peer);
3623 	NGI_SET_NODE(item, peernode);
3624 	SET_RETADDR(item, here, retaddr);
3625 
3626 	TOPOLOGY_RUNLOCK();
3627 
3628 	return (0);
3629 }
3630 
3631 int
3632 ng_address_path(node_p here, item_p item, const char *address, ng_ID_t retaddr)
3633 {
3634 	node_p	dest = NULL;
3635 	hook_p	hook = NULL;
3636 	int	error;
3637 
3638 	ITEM_DEBUG_CHECKS;
3639 	/*
3640 	 * Note that ng_path2noderef increments the reference count
3641 	 * on the node for us if it finds one. So we don't have to.
3642 	 */
3643 	error = ng_path2noderef(here, address, &dest, &hook);
3644 	if (error) {
3645 		NG_FREE_ITEM(item);
3646 		return (error);
3647 	}
3648 	NGI_SET_NODE(item, dest);
3649 	if (hook)
3650 		NGI_SET_HOOK(item, hook);
3651 
3652 	SET_RETADDR(item, here, retaddr);
3653 	return (0);
3654 }
3655 
3656 int
3657 ng_address_ID(node_p here, item_p item, ng_ID_t ID, ng_ID_t retaddr)
3658 {
3659 	node_p dest;
3660 
3661 	ITEM_DEBUG_CHECKS;
3662 	/*
3663 	 * Find the target node.
3664 	 */
3665 	dest = ng_ID2noderef(ID); /* GETS REFERENCE! */
3666 	if (dest == NULL) {
3667 		NG_FREE_ITEM(item);
3668 		TRAP_ERROR();
3669 		return(EINVAL);
3670 	}
3671 	/* Fill out the contents */
3672 	NGI_SET_NODE(item, dest);
3673 	NGI_CLR_HOOK(item);
3674 	SET_RETADDR(item, here, retaddr);
3675 	return (0);
3676 }
3677 
3678 /*
3679  * special case to send a message to self (e.g. destroy node)
3680  * Possibly indicate an arrival hook too.
3681  * Useful for removing that hook :-)
3682  */
3683 item_p
3684 ng_package_msg_self(node_p here, hook_p hook, struct ng_mesg *msg)
3685 {
3686 	item_p item;
3687 
3688 	/*
3689 	 * Find the target node.
3690 	 * If there is a HOOK argument, then use that in preference
3691 	 * to the address.
3692 	 */
3693 	if ((item = ng_alloc_item(NGQF_MESG, NG_NOFLAGS)) == NULL) {
3694 		NG_FREE_MSG(msg);
3695 		return (NULL);
3696 	}
3697 
3698 	/* Fill out the contents */
3699 	item->el_flags |= NGQF_WRITER;
3700 	NG_NODE_REF(here);
3701 	NGI_SET_NODE(item, here);
3702 	if (hook) {
3703 		NG_HOOK_REF(hook);
3704 		NGI_SET_HOOK(item, hook);
3705 	}
3706 	NGI_MSG(item) = msg;
3707 	NGI_RETADDR(item) = ng_node2ID(here);
3708 	return (item);
3709 }
3710 
3711 /*
3712  * Send ng_item_fn function call to the specified node.
3713  */
3714 
3715 int
3716 ng_send_fn(node_p node, hook_p hook, ng_item_fn *fn, void * arg1, int arg2)
3717 {
3718 
3719 	return ng_send_fn1(node, hook, fn, arg1, arg2, NG_NOFLAGS);
3720 }
3721 
3722 int
3723 ng_send_fn1(node_p node, hook_p hook, ng_item_fn *fn, void * arg1, int arg2,
3724 	int flags)
3725 {
3726 	item_p item;
3727 
3728 	if ((item = ng_alloc_item(NGQF_FN, flags)) == NULL) {
3729 		return (ENOMEM);
3730 	}
3731 	item->el_flags |= NGQF_WRITER;
3732 	NG_NODE_REF(node); /* and one for the item */
3733 	NGI_SET_NODE(item, node);
3734 	if (hook) {
3735 		NG_HOOK_REF(hook);
3736 		NGI_SET_HOOK(item, hook);
3737 	}
3738 	NGI_FN(item) = fn;
3739 	NGI_ARG1(item) = arg1;
3740 	NGI_ARG2(item) = arg2;
3741 	return(ng_snd_item(item, flags));
3742 }
3743 
3744 /*
3745  * Send ng_item_fn2 function call to the specified node.
3746  *
3747  * If an optional pitem parameter is supplied, its apply
3748  * callback will be copied to the new item. If also NG_REUSE_ITEM
3749  * flag is set, no new item will be allocated, but pitem will
3750  * be used.
3751  */
3752 int
3753 ng_send_fn2(node_p node, hook_p hook, item_p pitem, ng_item_fn2 *fn, void *arg1,
3754 	int arg2, int flags)
3755 {
3756 	item_p item;
3757 
3758 	KASSERT((pitem != NULL || (flags & NG_REUSE_ITEM) == 0),
3759 	    ("%s: NG_REUSE_ITEM but no pitem", __func__));
3760 
3761 	/*
3762 	 * Allocate a new item if no supplied or
3763 	 * if we can't use supplied one.
3764 	 */
3765 	if (pitem == NULL || (flags & NG_REUSE_ITEM) == 0) {
3766 		if ((item = ng_alloc_item(NGQF_FN2, flags)) == NULL)
3767 			return (ENOMEM);
3768 		if (pitem != NULL)
3769 			item->apply = pitem->apply;
3770 	} else {
3771 		if ((item = ng_realloc_item(pitem, NGQF_FN2, flags)) == NULL)
3772 			return (ENOMEM);
3773 	}
3774 
3775 	item->el_flags = (item->el_flags & ~NGQF_RW) | NGQF_WRITER;
3776 	NG_NODE_REF(node); /* and one for the item */
3777 	NGI_SET_NODE(item, node);
3778 	if (hook) {
3779 		NG_HOOK_REF(hook);
3780 		NGI_SET_HOOK(item, hook);
3781 	}
3782 	NGI_FN2(item) = fn;
3783 	NGI_ARG1(item) = arg1;
3784 	NGI_ARG2(item) = arg2;
3785 	return(ng_snd_item(item, flags));
3786 }
3787 
3788 /*
3789  * Official timeout routines for Netgraph nodes.
3790  */
3791 static void
3792 ng_callout_trampoline(void *arg)
3793 {
3794 	struct epoch_tracker et;
3795 	item_p item = arg;
3796 
3797 	NET_EPOCH_ENTER(et);
3798 	CURVNET_SET(NGI_NODE(item)->nd_vnet);
3799 	ng_snd_item(item, 0);
3800 	CURVNET_RESTORE();
3801 	NET_EPOCH_EXIT(et);
3802 }
3803 
3804 int
3805 ng_callout(struct callout *c, node_p node, hook_p hook, int ticks,
3806     ng_item_fn *fn, void * arg1, int arg2)
3807 {
3808 	item_p item, oitem;
3809 
3810 	if ((item = ng_alloc_item(NGQF_FN, NG_NOFLAGS)) == NULL)
3811 		return (ENOMEM);
3812 
3813 	item->el_flags |= NGQF_WRITER;
3814 	NG_NODE_REF(node);		/* and one for the item */
3815 	NGI_SET_NODE(item, node);
3816 	if (hook) {
3817 		NG_HOOK_REF(hook);
3818 		NGI_SET_HOOK(item, hook);
3819 	}
3820 	NGI_FN(item) = fn;
3821 	NGI_ARG1(item) = arg1;
3822 	NGI_ARG2(item) = arg2;
3823 	oitem = c->c_arg;
3824 	if (callout_reset(c, ticks, &ng_callout_trampoline, item) == 1 &&
3825 	    oitem != NULL)
3826 		NG_FREE_ITEM(oitem);
3827 	return (0);
3828 }
3829 
3830 /*
3831  * Free references and item if callout_stop/callout_drain returned 1,
3832  * meaning that callout was successfully stopped and now references
3833  * belong to us.
3834  */
3835 static void
3836 ng_uncallout_internal(struct callout *c, node_p node)
3837 {
3838 	item_p item;
3839 
3840 	item = c->c_arg;
3841 	if ((c->c_func == &ng_callout_trampoline) &&
3842 	    (item != NULL) && (NGI_NODE(item) == node)) {
3843 		/*
3844 		 * We successfully removed it from the queue before it ran
3845 		 * So now we need to unreference everything that was
3846 		 * given extra references. (NG_FREE_ITEM does this).
3847 		 */
3848 		NG_FREE_ITEM(item);
3849 	}
3850 	c->c_arg = NULL;
3851 }
3852 
3853 
3854 /* A special modified version of callout_stop() */
3855 int
3856 ng_uncallout(struct callout *c, node_p node)
3857 {
3858 	int rval;
3859 
3860 	rval = callout_stop(c);
3861 	if (rval > 0)
3862 		/*
3863 		 * XXXGL: in case if callout is already running and next
3864 		 * invocation is scheduled at the same time, callout_stop()
3865 		 * returns 0. See d153eeee97d. In this case netgraph(4) would
3866 		 * leak resources. However, no nodes are known to induce such
3867 		 * behavior.
3868 		 */
3869 		ng_uncallout_internal(c, node);
3870 
3871 	return (rval);
3872 }
3873 
3874 /* A special modified version of callout_drain() */
3875 int
3876 ng_uncallout_drain(struct callout *c, node_p node)
3877 {
3878 	int rval;
3879 
3880 	rval = callout_drain(c);
3881 	if (rval > 0)
3882 		ng_uncallout_internal(c, node);
3883 
3884 	return (rval);
3885 }
3886 
3887 /*
3888  * Set the address, if none given, give the node here.
3889  */
3890 void
3891 ng_replace_retaddr(node_p here, item_p item, ng_ID_t retaddr)
3892 {
3893 	if (retaddr) {
3894 		NGI_RETADDR(item) = retaddr;
3895 	} else {
3896 		/*
3897 		 * The old return address should be ok.
3898 		 * If there isn't one, use the address here.
3899 		 */
3900 		NGI_RETADDR(item) = ng_node2ID(here);
3901 	}
3902 }
3903