xref: /dragonfly/sys/netgraph7/ng_tag.c (revision 880a3c65)
1 /*-
2  * Copyright (c) 2006 Vadim Goncharov <vadimnuclight@tpu.ru>
3  * All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice unmodified, this list of conditions, and the following
10  *    disclaimer.
11  * 2. Redistributions in binary form must reproduce the above copyright
12  *    notice, this list of conditions and the following disclaimer in the
13  *    documentation and/or other materials provided with the distribution.
14  *
15  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
16  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
17  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
18  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
19  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
20  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
21  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
22  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
23  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
24  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
25  * SUCH DAMAGE.
26  *
27  * Portions Copyright (c) 1999 Whistle Communications, Inc.
28  * (ng_bpf by Archie Cobbs <archie@freebsd.org>)
29  *
30  * $FreeBSD: src/sys/netgraph/ng_tag.c,v 1.1 2006/06/27 12:45:28 glebius Exp $
31  * $DragonFly: src/sys/netgraph7/ng_tag.c,v 1.2 2008/06/26 23:05:35 dillon Exp $
32  */
33 
34 /*
35  * TAG NETGRAPH NODE TYPE
36  *
37  * This node type accepts an arbitrary number of hooks. Each hook can be
38  * configured for an mbuf_tags(9) definition and two hook names: a hook
39  * for matched packets, and a hook for packets, that didn't match. Incoming
40  * packets are examined for configured tag, matched packets are delivered
41  * out via first hook, and not matched out via second. If corresponding hook
42  * is not configured, packets are dropped.
43  *
44  * A hook can also have an outgoing tag definition configured, so that
45  * all packets leaving the hook will be unconditionally appended with newly
46  * allocated tag.
47  *
48  * Both hooks can be set to null tag definitions (that is, with zeroed
49  * fields), so that packet tags are unmodified on output or all packets
50  * are unconditionally forwarded to non-matching hook on input.  There is
51  * also a possibility to replace tags by specifying strip flag on input
52  * and replacing tag on corresponding output tag (or simply remove tag if
53  * no tag specified on output).
54  *
55  * If compiled with NG_TAG_DEBUG, each hook also keeps statistics about
56  * how many packets have matched, etc.
57  */
58 
59 #include <sys/param.h>
60 #include <sys/systm.h>
61 #include <sys/errno.h>
62 #include <sys/kernel.h>
63 #include <sys/malloc.h>
64 #include <sys/mbuf.h>
65 #include <sys/stddef.h>
66 
67 #include "ng_message.h"
68 #include "netgraph.h"
69 #include "ng_parse.h"
70 #include "ng_tag.h"
71 
72 #ifdef NG_SEPARATE_MALLOC
73 MALLOC_DEFINE(M_NETGRAPH_TAG, "netgraph_tag", "netgraph tag node ");
74 #else
75 #define M_NETGRAPH_TAG M_NETGRAPH
76 #endif
77 
78 #define ERROUT(x)	do { error = (x); goto done; } while (0)
79 
80 /*
81  * Per hook private info.
82  *
83  * We've separated API and ABI here, to make easier changes in this node,
84  * if needed. If you want to change representation, please do not break API.
85  * We still keep API structures in memory to simplify access to them for
86  * GET* messages, but most of data is accessed in internal representation
87  * only.  The reason for this is to speed things up - if data will be
88  * accessed from API structures, there would be double pointer dereferencing
89  * in the code, which almost necessarily leads to CPU cache misses and
90  * reloads.
91  *
92  * We also do another optimization by using resolved pointers to
93  * destination hooks instead of expensive ng_findhook().
94  */
95 struct ng_tag_hookinfo {
96 	hook_p			hi_match;	/* matching hook pointer */
97 	hook_p			hi_nonmatch;	/* non-matching hook pointer */
98 	uint32_t		in_tag_cookie;
99 	uint32_t		out_tag_cookie;
100 	uint16_t		in_tag_id;
101 	uint16_t		in_tag_len;
102 	uint16_t		out_tag_id;
103 	uint16_t		out_tag_len;
104 	uint8_t			strip;
105 	void			*in_tag_data;
106 	void			*out_tag_data;
107 	struct ng_tag_hookin	*in;
108 	struct ng_tag_hookout	*out;
109 #ifdef NG_TAG_DEBUG
110 	struct ng_tag_hookstat	stats;
111 #endif
112 };
113 typedef struct ng_tag_hookinfo *hinfo_p;
114 
115 /* Netgraph methods. */
116 static ng_constructor_t	ng_tag_constructor;
117 static ng_rcvmsg_t	ng_tag_rcvmsg;
118 static ng_shutdown_t	ng_tag_shutdown;
119 static ng_newhook_t	ng_tag_newhook;
120 static ng_rcvdata_t	ng_tag_rcvdata;
121 static ng_disconnect_t	ng_tag_disconnect;
122 
123 /* Internal helper functions. */
124 static int	ng_tag_setdata_in(hook_p hook, const struct ng_tag_hookin *hp);
125 static int	ng_tag_setdata_out(hook_p hook, const struct ng_tag_hookout *hp);
126 
127 /* Parse types for the field 'tag_data' in structs ng_tag_hookin and out. */
128 static int
129 ng_tag_hookinary_getLength(const struct ng_parse_type *type,
130 	const u_char *start, const u_char *buf)
131 {
132 	const struct ng_tag_hookin *hp;
133 
134 	hp = (const struct ng_tag_hookin *)
135 	    (buf - offsetof(struct ng_tag_hookin, tag_data));
136 	return (hp->tag_len);
137 }
138 
139 static int
140 ng_tag_hookoutary_getLength(const struct ng_parse_type *type,
141 	const u_char *start, const u_char *buf)
142 {
143 	const struct ng_tag_hookout *hp;
144 
145 	hp = (const struct ng_tag_hookout *)
146 	    (buf - offsetof(struct ng_tag_hookout, tag_data));
147 	return (hp->tag_len);
148 }
149 
150 static const struct ng_parse_type ng_tag_hookinary_type = {
151 	&ng_parse_bytearray_type,
152 	&ng_tag_hookinary_getLength
153 };
154 
155 static const struct ng_parse_type ng_tag_hookoutary_type = {
156 	&ng_parse_bytearray_type,
157 	&ng_tag_hookoutary_getLength
158 };
159 
160 /* Parse type for struct ng_tag_hookin. */
161 static const struct ng_parse_struct_field ng_tag_hookin_type_fields[]
162 	= NG_TAG_HOOKIN_TYPE_INFO(&ng_tag_hookinary_type);
163 static const struct ng_parse_type ng_tag_hookin_type = {
164 	&ng_parse_struct_type,
165 	&ng_tag_hookin_type_fields
166 };
167 
168 /* Parse type for struct ng_tag_hookout. */
169 static const struct ng_parse_struct_field ng_tag_hookout_type_fields[]
170 	= NG_TAG_HOOKOUT_TYPE_INFO(&ng_tag_hookoutary_type);
171 static const struct ng_parse_type ng_tag_hookout_type = {
172 	&ng_parse_struct_type,
173 	&ng_tag_hookout_type_fields
174 };
175 
176 #ifdef NG_TAG_DEBUG
177 /* Parse type for struct ng_tag_hookstat. */
178 static const struct ng_parse_struct_field ng_tag_hookstat_type_fields[]
179 	= NG_TAG_HOOKSTAT_TYPE_INFO;
180 static const struct ng_parse_type ng_tag_hookstat_type = {
181 	&ng_parse_struct_type,
182 	&ng_tag_hookstat_type_fields
183 };
184 #endif
185 
186 /* List of commands and how to convert arguments to/from ASCII. */
187 static const struct ng_cmdlist ng_tag_cmdlist[] = {
188 	{
189 	  NGM_TAG_COOKIE,
190 	  NGM_TAG_SET_HOOKIN,
191 	  "sethookin",
192 	  &ng_tag_hookin_type,
193 	  NULL
194 	},
195 	{
196 	  NGM_TAG_COOKIE,
197 	  NGM_TAG_GET_HOOKIN,
198 	  "gethookin",
199 	  &ng_parse_hookbuf_type,
200 	  &ng_tag_hookin_type
201 	},
202 	{
203 	  NGM_TAG_COOKIE,
204 	  NGM_TAG_SET_HOOKOUT,
205 	  "sethookout",
206 	  &ng_tag_hookout_type,
207 	  NULL
208 	},
209 	{
210 	  NGM_TAG_COOKIE,
211 	  NGM_TAG_GET_HOOKOUT,
212 	  "gethookout",
213 	  &ng_parse_hookbuf_type,
214 	  &ng_tag_hookout_type
215 	},
216 #ifdef NG_TAG_DEBUG
217 	{
218 	  NGM_TAG_COOKIE,
219 	  NGM_TAG_GET_STATS,
220 	  "getstats",
221 	  &ng_parse_hookbuf_type,
222 	  &ng_tag_hookstat_type
223 	},
224 	{
225 	  NGM_TAG_COOKIE,
226 	  NGM_TAG_CLR_STATS,
227 	  "clrstats",
228 	  &ng_parse_hookbuf_type,
229 	  NULL
230 	},
231 	{
232 	  NGM_TAG_COOKIE,
233 	  NGM_TAG_GETCLR_STATS,
234 	  "getclrstats",
235 	  &ng_parse_hookbuf_type,
236 	  &ng_tag_hookstat_type
237 	},
238 #endif
239 	{ 0 }
240 };
241 
242 /* Netgraph type descriptor. */
243 static struct ng_type typestruct = {
244 	.version =	NG_ABI_VERSION,
245 	.name =		NG_TAG_NODE_TYPE,
246 	.constructor =	ng_tag_constructor,
247 	.rcvmsg =	ng_tag_rcvmsg,
248 	.shutdown =	ng_tag_shutdown,
249 	.newhook =	ng_tag_newhook,
250 	.rcvdata =	ng_tag_rcvdata,
251 	.disconnect =	ng_tag_disconnect,
252 	.cmdlist =	ng_tag_cmdlist,
253 };
254 NETGRAPH_INIT(tag, &typestruct);
255 
256 /*
257  * This are default API structures (initialized to zeroes) which are
258  * returned in response to GET* messages when no configuration was made.
259  * One could ask why to have this structures at all when we have
260  * ng_tag_hookinfo initialized to zero and don't need in and out structures
261  * at all to operate.  Unfortunatelly, we have to return thisHook field
262  * in response to messages so the fastest and simpliest way is to have
263  * this default structures and initialize thisHook once at hook creation
264  * rather than to do it on every response.
265  */
266 
267 /* Default tag values for a hook that matches nothing. */
268 static const struct ng_tag_hookin ng_tag_default_in = {
269 	{ '\0' },		/* to be filled in at hook creation time */
270 	{ '\0' },
271 	{ '\0' },
272 	0,
273 	0,
274 	0,
275 	0
276 };
277 
278 /* Default tag values for a hook that adds nothing */
279 static const struct ng_tag_hookout ng_tag_default_out = {
280 	{ '\0' },		/* to be filled in at hook creation time */
281 	0,
282 	0,
283 	0
284 };
285 
286 /*
287  * Node constructor.
288  *
289  * We don't keep any per-node private data - we do it on per-hook basis.
290  */
291 static int
292 ng_tag_constructor(node_p node)
293 {
294 	return (0);
295 }
296 
297 /*
298  * Add a hook.
299  */
300 static int
301 ng_tag_newhook(node_p node, hook_p hook, const char *name)
302 {
303 	hinfo_p hip;
304 	int error;
305 
306 	/* Create hook private structure. */
307 	hip = kmalloc(sizeof(*hip), M_NETGRAPH_TAG, M_WAITOK | M_ZERO);
308 	/* M_WAITOK can't return NULL. */
309 	NG_HOOK_SET_PRIVATE(hook, hip);
310 
311 	/*
312 	 * After M_ZERO both in and out hook pointers are set to NULL,
313 	 * as well as all members and pointers to in and out API
314 	 * structures, so we need to set explicitly only thisHook field
315 	 * in that structures (after allocating them, of course).
316 	 */
317 
318 	/* Attach the default IN data. */
319 	if ((error = ng_tag_setdata_in(hook, &ng_tag_default_in)) != 0) {
320 		kfree(hip, M_NETGRAPH_TAG);
321 		return (error);
322 	}
323 
324 	/* Attach the default OUT data. */
325 	if ((error = ng_tag_setdata_out(hook, &ng_tag_default_out)) != 0) {
326 		kfree(hip, M_NETGRAPH_TAG);
327 		return (error);
328 	}
329 
330 	/*
331 	 * Set hook name.  This is done only once at hook creation time
332 	 * since hook name can't change, rather than to do it on every
333 	 * response to messages requesting API structures with data who
334 	 * we are etc.
335 	 */
336 	strncpy(hip->in->thisHook, name, sizeof(hip->in->thisHook) - 1);
337 	hip->in->thisHook[sizeof(hip->in->thisHook) - 1] = '\0';
338 	strncpy(hip->out->thisHook, name, sizeof(hip->out->thisHook) - 1);
339 	hip->out->thisHook[sizeof(hip->out->thisHook) - 1] = '\0';
340 	return (0);
341 }
342 
343 /*
344  * Receive a control message.
345  */
346 static int
347 ng_tag_rcvmsg(node_p node, item_p item, hook_p lasthook)
348 {
349 	struct ng_mesg *msg;
350 	struct ng_mesg *resp = NULL;
351 	int error = 0;
352 
353 	NGI_GET_MSG(item, msg);
354 	switch (msg->header.typecookie) {
355 	case NGM_TAG_COOKIE:
356 		switch (msg->header.cmd) {
357 		case NGM_TAG_SET_HOOKIN:
358 		    {
359 			struct ng_tag_hookin *const
360 			    hp = (struct ng_tag_hookin *)msg->data;
361 			hook_p hook;
362 
363 			/* Sanity check. */
364 			if (msg->header.arglen < sizeof(*hp)
365 			    || msg->header.arglen !=
366 			    NG_TAG_HOOKIN_SIZE(hp->tag_len))
367 				ERROUT(EINVAL);
368 
369 			/* Find hook. */
370 			if ((hook = ng_findhook(node, hp->thisHook)) == NULL)
371 				ERROUT(ENOENT);
372 
373 			/* Set new tag values. */
374 			if ((error = ng_tag_setdata_in(hook, hp)) != 0)
375 				ERROUT(error);
376 			break;
377 		    }
378 
379 		case NGM_TAG_SET_HOOKOUT:
380 		    {
381 			struct ng_tag_hookout *const
382 			    hp = (struct ng_tag_hookout *)msg->data;
383 			hook_p hook;
384 
385 			/* Sanity check. */
386 			if (msg->header.arglen < sizeof(*hp)
387 			    || msg->header.arglen !=
388 			    NG_TAG_HOOKOUT_SIZE(hp->tag_len))
389 				ERROUT(EINVAL);
390 
391 			/* Find hook. */
392 			if ((hook = ng_findhook(node, hp->thisHook)) == NULL)
393 				ERROUT(ENOENT);
394 
395 			/* Set new tag values. */
396 			if ((error = ng_tag_setdata_out(hook, hp)) != 0)
397 				ERROUT(error);
398 			break;
399 		    }
400 
401 		case NGM_TAG_GET_HOOKIN:
402 		    {
403 			struct ng_tag_hookin *hp;
404 			hook_p hook;
405 
406 			/* Sanity check. */
407 			if (msg->header.arglen == 0)
408 				ERROUT(EINVAL);
409 			msg->data[msg->header.arglen - 1] = '\0';
410 
411 			/* Find hook. */
412 			if ((hook = ng_findhook(node, msg->data)) == NULL)
413 				ERROUT(ENOENT);
414 
415 			/* Build response. */
416 			hp = ((hinfo_p)NG_HOOK_PRIVATE(hook))->in;
417 			NG_MKRESPONSE(resp, msg,
418 			    NG_TAG_HOOKIN_SIZE(hp->tag_len), M_WAITOK);
419 			/* M_WAITOK can't return NULL. */
420 			bcopy(hp, resp->data,
421 			   NG_TAG_HOOKIN_SIZE(hp->tag_len));
422 			break;
423 		    }
424 
425 		case NGM_TAG_GET_HOOKOUT:
426 		    {
427 			struct ng_tag_hookout *hp;
428 			hook_p hook;
429 
430 			/* Sanity check. */
431 			if (msg->header.arglen == 0)
432 				ERROUT(EINVAL);
433 			msg->data[msg->header.arglen - 1] = '\0';
434 
435 			/* Find hook. */
436 			if ((hook = ng_findhook(node, msg->data)) == NULL)
437 				ERROUT(ENOENT);
438 
439 			/* Build response. */
440 			hp = ((hinfo_p)NG_HOOK_PRIVATE(hook))->out;
441 			NG_MKRESPONSE(resp, msg,
442 			    NG_TAG_HOOKOUT_SIZE(hp->tag_len), M_WAITOK);
443 			/* M_WAITOK can't return NULL. */
444 			bcopy(hp, resp->data,
445 			   NG_TAG_HOOKOUT_SIZE(hp->tag_len));
446 			break;
447 		    }
448 
449 #ifdef NG_TAG_DEBUG
450 		case NGM_TAG_GET_STATS:
451 		case NGM_TAG_CLR_STATS:
452 		case NGM_TAG_GETCLR_STATS:
453 		    {
454 			struct ng_tag_hookstat *stats;
455 			hook_p hook;
456 
457 			/* Sanity check. */
458 			if (msg->header.arglen == 0)
459 				ERROUT(EINVAL);
460 			msg->data[msg->header.arglen - 1] = '\0';
461 
462 			/* Find hook. */
463 			if ((hook = ng_findhook(node, msg->data)) == NULL)
464 				ERROUT(ENOENT);
465 			stats = &((hinfo_p)NG_HOOK_PRIVATE(hook))->stats;
466 
467 			/* Build response (if desired). */
468 			if (msg->header.cmd != NGM_TAG_CLR_STATS) {
469 				NG_MKRESPONSE(resp,
470 				    msg, sizeof(*stats), M_WAITOK);
471 				/* M_WAITOK can't return NULL. */
472 				bcopy(stats, resp->data, sizeof(*stats));
473 			}
474 
475 			/* Clear stats (if desired). */
476 			if (msg->header.cmd != NGM_TAG_GET_STATS)
477 				bzero(stats, sizeof(*stats));
478 			break;
479 		    }
480 #endif /* NG_TAG_DEBUG */
481 
482 		default:
483 			error = EINVAL;
484 			break;
485 		}
486 		break;
487 	default:
488 		error = EINVAL;
489 		break;
490 	}
491 done:
492 	NG_RESPOND_MSG(error, node, item, resp);
493 	NG_FREE_MSG(msg);
494 	return (error);
495 }
496 
497 /*
498  * Receive data on a hook.
499  *
500  * Apply the filter, and then drop or forward packet as appropriate.
501  */
502 static int
503 ng_tag_rcvdata(hook_p hook, item_p item)
504 {
505 	struct mbuf *m;
506 	struct m_tag *tag = NULL;
507 	const hinfo_p hip = NG_HOOK_PRIVATE(hook);
508 	uint16_t type, tag_len;
509 	uint32_t cookie;
510 	hinfo_p dhip;
511 	hook_p dest;
512 	int totlen;
513 	int found = 0, error = 0;
514 
515 	m = NGI_M(item);	/* 'item' still owns it.. we are peeking */
516 	totlen = m->m_pkthdr.len;
517 
518 #ifdef NG_TAG_DEBUG
519 	hip->stats.recvFrames++;
520 	hip->stats.recvOctets += totlen;
521 #endif
522 
523 	/* Looking up incoming tag. */
524 	cookie = hip->in_tag_cookie;
525 	type = hip->in_tag_id;
526 	tag_len = hip->in_tag_len;
527 
528 	/*
529 	 * We treat case of all zeroes specially (that is, cookie and
530 	 * type are equal to zero), as we assume that such tag
531 	 * can never occur in the wild.  So we don't waste time trying
532 	 * to find such tag (for example, these are zeroes after hook
533 	 * creation in default structures).
534 	 */
535 	if ((cookie != 0) || (type != 0)) {
536 		tag = m_tag_locate(m, cookie, type, NULL);
537 		while (tag != NULL) {
538 			if (memcmp((void *)(tag + 1),
539 			    hip->in_tag_data, tag_len) == 0) {
540 				found = 1;
541 				break;
542 			}
543 			tag = m_tag_locate(m, cookie, type, tag);
544 		}
545 	}
546 
547 	/* See if we got a match and find destination hook. */
548 	if (found) {
549 #ifdef NG_TAG_DEBUG
550 		hip->stats.recvMatchFrames++;
551 		hip->stats.recvMatchOctets += totlen;
552 #endif
553 		if (hip->strip)
554 			m_tag_delete(m, tag);
555 		dest = hip->hi_match;
556 	} else
557 		dest = hip->hi_nonmatch;
558 	if (dest == NULL) {
559 		NG_FREE_ITEM(item);
560 		return (0);
561 	}
562 
563 	/* Deliver frame out destination hook. */
564 	dhip = NG_HOOK_PRIVATE(dest);
565 
566 #ifdef NG_TAG_DEBUG
567 	dhip->stats.xmitOctets += totlen;
568 	dhip->stats.xmitFrames++;
569 #endif
570 
571 	cookie = dhip->out_tag_cookie;
572 	type = dhip->out_tag_id;
573 	tag_len = dhip->out_tag_len;
574 
575 	if ((cookie != 0) || (type != 0)) {
576 		tag = m_tag_alloc(cookie, type, tag_len, MB_DONTWAIT);
577 		/* XXX may be free the mbuf if tag allocation failed? */
578 		if (tag != NULL) {
579 			if (tag_len != 0) {
580 				/* copy tag data to its place */
581 				memcpy((void *)(tag + 1),
582 				    dhip->out_tag_data, tag_len);
583 			}
584 			m_tag_prepend(m, tag);
585 		}
586 	}
587 
588 	NG_FWD_ITEM_HOOK(error, item, dest);
589 	return (error);
590 }
591 
592 /*
593  * Shutdown processing.
594  */
595 static int
596 ng_tag_shutdown(node_p node)
597 {
598 	NG_NODE_UNREF(node);
599 	return (0);
600 }
601 
602 /*
603  * Hook disconnection.
604  *
605  * We must check all hooks, since they may reference this one.
606  */
607 static int
608 ng_tag_disconnect(hook_p hook)
609 {
610 	const hinfo_p hip = NG_HOOK_PRIVATE(hook);
611 	node_p node = NG_HOOK_NODE(hook);
612 	hook_p hook2;
613 
614 	KASSERT(hip != NULL, ("%s: null info", __func__));
615 
616 	LIST_FOREACH(hook2, &node->nd_hooks, hk_hooks) {
617 		hinfo_p priv = NG_HOOK_PRIVATE(hook2);
618 
619 		if (priv->hi_match == hook)
620 			priv->hi_match = NULL;
621 		if (priv->hi_nonmatch == hook)
622 			priv->hi_nonmatch = NULL;
623 	}
624 
625 	kfree(hip->in, M_NETGRAPH_TAG);
626 	kfree(hip->out, M_NETGRAPH_TAG);
627 	kfree(hip, M_NETGRAPH_TAG);
628 	NG_HOOK_SET_PRIVATE(hook, NULL);			/* for good measure */
629 	if ((NG_NODE_NUMHOOKS(NG_HOOK_NODE(hook)) == 0) &&
630 	    (NG_NODE_IS_VALID(NG_HOOK_NODE(hook)))) {
631 		ng_rmnode_self(NG_HOOK_NODE(hook));
632 	}
633 	return (0);
634 }
635 
636 /************************************************************************
637 			HELPER STUFF
638  ************************************************************************/
639 
640 /*
641  * Set the IN tag values associated with a hook.
642  */
643 static int
644 ng_tag_setdata_in(hook_p hook, const struct ng_tag_hookin *hp0)
645 {
646 	const hinfo_p hip = NG_HOOK_PRIVATE(hook);
647 	struct ng_tag_hookin *hp;
648 	int size;
649 
650 	/* Make a copy of the tag values and data. */
651 	size = NG_TAG_HOOKIN_SIZE(hp0->tag_len);
652 	hp = kmalloc(size, M_NETGRAPH_TAG, M_WAITOK);
653 	/* M_WAITOK can't return NULL. */
654 	bcopy(hp0, hp, size);
655 
656 	/* Free previous tag, if any, and assign new one. */
657 	if (hip->in != NULL)
658 		kfree(hip->in, M_NETGRAPH_TAG);
659 	hip->in = hp;
660 
661 	/*
662 	 * Resolve hook names to pointers.
663 	 *
664 	 * As ng_findhook() is expensive operation to do it on every packet
665 	 * after tag matching check, we do it here and use resolved pointers
666 	 * where appropriate.
667 	 *
668 	 * XXX The drawback is that user can configure a hook to use
669 	 * ifMatch/ifNotMatch hooks that do not yet exist and will be added
670 	 * by user later, so that resolved pointers will be NULL even
671 	 * if the hook already exists, causing node to drop packets and
672 	 * user to report bugs.  We could do check for this situation on
673 	 * every hook creation with pointers correction, but that involves
674 	 * re-resolving for all pointers in all hooks, up to O(n^2) operations,
675 	 * so we better document this in man page for user not to do
676 	 * configuration before creating all hooks.
677 	 */
678 	hip->hi_match = ng_findhook(NG_HOOK_NODE(hook), hip->in->ifMatch);
679 	hip->hi_nonmatch = ng_findhook(NG_HOOK_NODE(hook), hip->in->ifNotMatch);
680 
681 	/* Fill internal values from API structures. */
682 	hip->in_tag_cookie = hip->in->tag_cookie;
683 	hip->in_tag_id = hip->in->tag_id;
684 	hip->in_tag_len = hip->in->tag_len;
685 	hip->strip = hip->in->strip;
686 	hip->in_tag_data = (void*)(hip->in->tag_data);
687 	return (0);
688 }
689 
690 /*
691  * Set the OUT tag values associated with a hook.
692  */
693 static int
694 ng_tag_setdata_out(hook_p hook, const struct ng_tag_hookout *hp0)
695 {
696 	const hinfo_p hip = NG_HOOK_PRIVATE(hook);
697 	struct ng_tag_hookout *hp;
698 	int size;
699 
700 	/* Make a copy of the tag values and data. */
701 	size = NG_TAG_HOOKOUT_SIZE(hp0->tag_len);
702 	hp = kmalloc(size, M_NETGRAPH_TAG, M_WAITOK);
703 	/* M_WAITOK can't return NULL. */
704 	bcopy(hp0, hp, size);
705 
706 	/* Free previous tag, if any, and assign new one. */
707 	if (hip->out != NULL)
708 		kfree(hip->out, M_NETGRAPH_TAG);
709 	hip->out = hp;
710 
711 	/* Fill internal values from API structures. */
712 	hip->out_tag_cookie = hip->out->tag_cookie;
713 	hip->out_tag_id = hip->out->tag_id;
714 	hip->out_tag_len = hip->out->tag_len;
715 	hip->out_tag_data = (void*)(hip->out->tag_data);
716 	return (0);
717 }
718 
719