xref: /freebsd/sys/netgraph/ng_car.c (revision 5bb3134a8c21cb87b30e135ef168483f0333dabb)
1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
3  *
4  * Copyright (c) 2005 Nuno Antunes <nuno.antunes@gmail.com>
5  * Copyright (c) 2007 Alexander Motin <mav@freebsd.org>
6  * Copyright (c) 2019 Lutz Donnerhacke <lutz@donnerhacke.de>
7  * All rights reserved.
8  *
9  * Redistribution and use in source and binary forms, with or without
10  * modification, are permitted provided that the following conditions
11  * are met:
12  * 1. Redistributions of source code must retain the above copyright
13  *    notice, this list of conditions and the following disclaimer.
14  * 2. Redistributions in binary form must reproduce the above copyright
15  *    notice, this list of conditions and the following disclaimer in the
16  *    documentation and/or other materials provided with the distribution.
17  *
18  * THIS SOFTWARE IS PROVIDED BY AUTHOR AND CONTRIBUTORS ``AS IS'' AND
19  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
20  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
21  * ARE DISCLAIMED.  IN NO EVENT SHALL AUTHOR OR CONTRIBUTORS BE LIABLE
22  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
23  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
24  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
25  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
26  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
27  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
28  * SUCH DAMAGE.
29  *
30  * $FreeBSD$
31  */
32 
33 /*
34  * ng_car - An implementation of committed access rate for netgraph
35  *
36  * TODO:
37  *	- Sanitize input config values (impose some limits)
38  *	- Implement DSCP marking for IPv4
39  *	- Decouple functionality into a simple classifier (g/y/r)
40  *	  and various action nodes (i.e. shape, dcsp, pcp)
41  */
42 
43 #include <sys/param.h>
44 #include <sys/errno.h>
45 #include <sys/kernel.h>
46 #include <sys/malloc.h>
47 #include <sys/mbuf.h>
48 
49 #include <netgraph/ng_message.h>
50 #include <netgraph/ng_parse.h>
51 #include <netgraph/netgraph.h>
52 #include <netgraph/ng_car.h>
53 
54 #include "qos.h"
55 
56 #define NG_CAR_QUEUE_SIZE	100	/* Maximum queue size for SHAPE mode */
57 #define NG_CAR_QUEUE_MIN_TH	8	/* Minimum RED threshold for SHAPE mode */
58 
59 /* Hook private info */
60 struct hookinfo {
61 	hook_p		hook;		/* this (source) hook */
62 	hook_p		dest;		/* destination hook */
63 
64 	int64_t 	tc;		/* committed token bucket counter */
65 	int64_t 	te;		/* exceeded/peak token bucket counter */
66 	struct bintime	lastRefill;	/* last token refill time */
67 
68 	struct ng_car_hookconf conf;	/* hook configuration */
69 	struct ng_car_hookstats stats;	/* hook stats */
70 
71 	struct mbuf	*q[NG_CAR_QUEUE_SIZE];	/* circular packet queue */
72 	u_int		q_first;	/* first queue element */
73 	u_int		q_last;		/* last queue element */
74 	struct callout	q_callout;	/* periodic queue processing routine */
75 	struct mtx	q_mtx;		/* queue mutex */
76 };
77 
78 /* Private information for each node instance */
79 struct privdata {
80 	node_p node;				/* the node itself */
81 	struct hookinfo upper;			/* hook to upper layers */
82 	struct hookinfo lower;			/* hook to lower layers */
83 };
84 typedef struct privdata *priv_p;
85 
86 static ng_constructor_t	ng_car_constructor;
87 static ng_rcvmsg_t	ng_car_rcvmsg;
88 static ng_shutdown_t	ng_car_shutdown;
89 static ng_newhook_t	ng_car_newhook;
90 static ng_rcvdata_t	ng_car_rcvdata;
91 static ng_disconnect_t	ng_car_disconnect;
92 
93 static void	ng_car_refillhook(struct hookinfo *h);
94 static void	ng_car_schedule(struct hookinfo *h);
95 void		ng_car_q_event(node_p node, hook_p hook, void *arg, int arg2);
96 static void	ng_car_enqueue(struct hookinfo *h, item_p item);
97 
98 /* Parse type for struct ng_car_hookstats */
99 static const struct ng_parse_struct_field ng_car_hookstats_type_fields[]
100 	= NG_CAR_HOOKSTATS;
101 static const struct ng_parse_type ng_car_hookstats_type = {
102 	&ng_parse_struct_type,
103 	&ng_car_hookstats_type_fields
104 };
105 
106 /* Parse type for struct ng_car_bulkstats */
107 static const struct ng_parse_struct_field ng_car_bulkstats_type_fields[]
108 	= NG_CAR_BULKSTATS(&ng_car_hookstats_type);
109 static const struct ng_parse_type ng_car_bulkstats_type = {
110 	&ng_parse_struct_type,
111 	&ng_car_bulkstats_type_fields
112 };
113 
114 /* Parse type for struct ng_car_hookconf */
115 static const struct ng_parse_struct_field ng_car_hookconf_type_fields[]
116 	= NG_CAR_HOOKCONF;
117 static const struct ng_parse_type ng_car_hookconf_type = {
118 	&ng_parse_struct_type,
119 	&ng_car_hookconf_type_fields
120 };
121 
122 /* Parse type for struct ng_car_bulkconf */
123 static const struct ng_parse_struct_field ng_car_bulkconf_type_fields[]
124 	= NG_CAR_BULKCONF(&ng_car_hookconf_type);
125 static const struct ng_parse_type ng_car_bulkconf_type = {
126 	&ng_parse_struct_type,
127 	&ng_car_bulkconf_type_fields
128 };
129 
130 /* Command list */
131 static struct ng_cmdlist ng_car_cmdlist[] = {
132 	{
133 	  NGM_CAR_COOKIE,
134 	  NGM_CAR_GET_STATS,
135 	  "getstats",
136 	  NULL,
137 	  &ng_car_bulkstats_type,
138 	},
139 	{
140 	  NGM_CAR_COOKIE,
141 	  NGM_CAR_CLR_STATS,
142 	  "clrstats",
143 	  NULL,
144 	  NULL,
145 	},
146 	{
147 	  NGM_CAR_COOKIE,
148 	  NGM_CAR_GETCLR_STATS,
149 	  "getclrstats",
150 	  NULL,
151 	  &ng_car_bulkstats_type,
152 	},
153 
154 	{
155 	  NGM_CAR_COOKIE,
156 	  NGM_CAR_GET_CONF,
157 	  "getconf",
158 	  NULL,
159 	  &ng_car_bulkconf_type,
160 	},
161 	{
162 	  NGM_CAR_COOKIE,
163 	  NGM_CAR_SET_CONF,
164 	  "setconf",
165 	  &ng_car_bulkconf_type,
166 	  NULL,
167 	},
168 	{ 0 }
169 };
170 
171 /* Netgraph node type descriptor */
172 static struct ng_type ng_car_typestruct = {
173 	.version =	NG_ABI_VERSION,
174 	.name =		NG_CAR_NODE_TYPE,
175 	.constructor =	ng_car_constructor,
176 	.rcvmsg =	ng_car_rcvmsg,
177 	.shutdown =	ng_car_shutdown,
178 	.newhook =	ng_car_newhook,
179 	.rcvdata =	ng_car_rcvdata,
180 	.disconnect =	ng_car_disconnect,
181 	.cmdlist =	ng_car_cmdlist,
182 };
183 NETGRAPH_INIT(car, &ng_car_typestruct);
184 
185 /*
186  * Node constructor
187  */
188 static int
189 ng_car_constructor(node_p node)
190 {
191 	priv_p priv;
192 
193 	/* Initialize private descriptor. */
194 	priv = malloc(sizeof(*priv), M_NETGRAPH, M_WAITOK | M_ZERO);
195 
196 	NG_NODE_SET_PRIVATE(node, priv);
197 	priv->node = node;
198 
199 	/*
200 	 * Arbitrary default values
201 	 */
202 
203 	priv->upper.hook = NULL;
204 	priv->upper.dest = NULL;
205 	priv->upper.tc = priv->upper.conf.cbs = NG_CAR_CBS_MIN;
206 	priv->upper.te = priv->upper.conf.ebs = NG_CAR_EBS_MIN;
207 	priv->upper.conf.cir = NG_CAR_CIR_DFLT;
208 	priv->upper.conf.green_action = NG_CAR_ACTION_FORWARD;
209 	priv->upper.conf.yellow_action = NG_CAR_ACTION_FORWARD;
210 	priv->upper.conf.red_action = NG_CAR_ACTION_DROP;
211 	priv->upper.conf.mode = 0;
212 	getbinuptime(&priv->upper.lastRefill);
213 	priv->upper.q_first = 0;
214 	priv->upper.q_last = 0;
215 	ng_callout_init(&priv->upper.q_callout);
216 	mtx_init(&priv->upper.q_mtx, "ng_car_u", NULL, MTX_DEF);
217 
218 	priv->lower.hook = NULL;
219 	priv->lower.dest = NULL;
220 	priv->lower.tc = priv->lower.conf.cbs = NG_CAR_CBS_MIN;
221 	priv->lower.te = priv->lower.conf.ebs = NG_CAR_EBS_MIN;
222 	priv->lower.conf.cir = NG_CAR_CIR_DFLT;
223 	priv->lower.conf.green_action = NG_CAR_ACTION_FORWARD;
224 	priv->lower.conf.yellow_action = NG_CAR_ACTION_FORWARD;
225 	priv->lower.conf.red_action = NG_CAR_ACTION_DROP;
226 	priv->lower.conf.mode = 0;
227 	priv->lower.lastRefill = priv->upper.lastRefill;
228 	priv->lower.q_first = 0;
229 	priv->lower.q_last = 0;
230 	ng_callout_init(&priv->lower.q_callout);
231 	mtx_init(&priv->lower.q_mtx, "ng_car_l", NULL, MTX_DEF);
232 
233 	return (0);
234 }
235 
236 /*
237  * Add a hook.
238  */
239 static int
240 ng_car_newhook(node_p node, hook_p hook, const char *name)
241 {
242 	const priv_p priv = NG_NODE_PRIVATE(node);
243 
244 	if (strcmp(name, NG_CAR_HOOK_LOWER) == 0) {
245 		priv->lower.hook = hook;
246 		priv->upper.dest = hook;
247 		bzero(&priv->lower.stats, sizeof(priv->lower.stats));
248 		NG_HOOK_SET_PRIVATE(hook, &priv->lower);
249 	} else if (strcmp(name, NG_CAR_HOOK_UPPER) == 0) {
250 		priv->upper.hook = hook;
251 		priv->lower.dest = hook;
252 		bzero(&priv->upper.stats, sizeof(priv->upper.stats));
253 		NG_HOOK_SET_PRIVATE(hook, &priv->upper);
254 	} else
255 		return (EINVAL);
256 	return(0);
257 }
258 
259 /*
260  * Data has arrived.
261  */
262 static int
263 ng_car_rcvdata(hook_p hook, item_p item )
264 {
265 	struct hookinfo *const hinfo = NG_HOOK_PRIVATE(hook);
266 	struct mbuf *m;
267 	struct m_qos_color *colp;
268 	enum qos_color col;
269 	int error = 0;
270 	u_int len;
271 
272 	/* If queue is not empty now then enqueue packet. */
273 	if (hinfo->q_first != hinfo->q_last) {
274 		ng_car_enqueue(hinfo, item);
275 		return (0);
276 	}
277 
278 	m = NGI_M(item);
279 
280 #define NG_CAR_PERFORM_MATCH_ACTION(a,col)			\
281 	do {						\
282 		switch (a) {				\
283 		case NG_CAR_ACTION_FORWARD:		\
284 			/* Do nothing. */		\
285 			break;				\
286 		case NG_CAR_ACTION_MARK:		\
287 			if (colp == NULL) {		\
288 				colp = (void *)m_tag_alloc(		\
289 				    M_QOS_COOKIE, M_QOS_COLOR,		\
290 				    MTAG_SIZE(m_qos_color), M_NOWAIT);	\
291 				if (colp != NULL)			\
292 				    m_tag_prepend(m, &colp->tag);	\
293 			}				\
294 			if (colp != NULL)		\
295 			    colp->color = col;		\
296 			break;				\
297 		case NG_CAR_ACTION_DROP:		\
298 		default:				\
299 			/* Drop packet and return. */	\
300 			NG_FREE_ITEM(item);		\
301 			++hinfo->stats.dropped_pkts;	\
302 			return (0);			\
303 		}					\
304 	} while (0)
305 
306 	/* Packet is counted as 128 tokens for better resolution */
307 	if (hinfo->conf.opt & NG_CAR_COUNT_PACKETS) {
308 		len = 128;
309 	} else {
310 		len = m->m_pkthdr.len;
311 	}
312 
313 	/* Determine current color of the packet (default green) */
314 	colp = (void *)m_tag_locate(m, M_QOS_COOKIE, M_QOS_COLOR, NULL);
315 	if ((hinfo->conf.opt & NG_CAR_COLOR_AWARE) && (colp != NULL))
316 	    col = colp->color;
317 	else
318 	    col = QOS_COLOR_GREEN;
319 
320 	/* Check committed token bucket. */
321 	if (hinfo->tc - len >= 0 && col <= QOS_COLOR_GREEN) {
322 		/* This packet is green. */
323 		++hinfo->stats.green_pkts;
324 		hinfo->tc -= len;
325 		NG_CAR_PERFORM_MATCH_ACTION(
326 		    hinfo->conf.green_action,
327 		    QOS_COLOR_GREEN);
328 	} else {
329 		/* Refill only if not green without it. */
330 		ng_car_refillhook(hinfo);
331 
332 		 /* Check committed token bucket again after refill. */
333 		if (hinfo->tc - len >= 0 && col <= QOS_COLOR_GREEN) {
334 			/* This packet is green */
335 			++hinfo->stats.green_pkts;
336 			hinfo->tc -= len;
337 			NG_CAR_PERFORM_MATCH_ACTION(
338 			    hinfo->conf.green_action,
339 			    QOS_COLOR_GREEN);
340 
341 		/* If not green and mode is SHAPE, enqueue packet. */
342 		} else if (hinfo->conf.mode == NG_CAR_SHAPE) {
343 			ng_car_enqueue(hinfo, item);
344 			return (0);
345 
346 		/* If not green and mode is RED, calculate probability. */
347 		} else if (hinfo->conf.mode == NG_CAR_RED) {
348 			/* Is packet is bigger then extended burst? */
349 			if (len - (hinfo->tc - len) > hinfo->conf.ebs ||
350 			    col >= QOS_COLOR_RED) {
351 				/* This packet is definitely red. */
352 				++hinfo->stats.red_pkts;
353 				hinfo->te = 0;
354 				NG_CAR_PERFORM_MATCH_ACTION(
355 					hinfo->conf.red_action,
356 					QOS_COLOR_RED);
357 
358 			/* Use token bucket to simulate RED-like drop
359 			   probability. */
360 			} else if (hinfo->te + (len - hinfo->tc) < hinfo->conf.ebs &&
361 				   col <= QOS_COLOR_YELLOW) {
362 				/* This packet is yellow */
363 				++hinfo->stats.yellow_pkts;
364 				hinfo->te += len - hinfo->tc;
365 				/* Go to negative tokens. */
366 				hinfo->tc -= len;
367 				NG_CAR_PERFORM_MATCH_ACTION(
368 				    hinfo->conf.yellow_action,
369 				    QOS_COLOR_YELLOW);
370 			} else {
371 				/* This packet is probably red. */
372 				++hinfo->stats.red_pkts;
373 				hinfo->te = 0;
374 				NG_CAR_PERFORM_MATCH_ACTION(
375 				    hinfo->conf.red_action,
376 				    QOS_COLOR_RED);
377 			}
378 		/* If not green and mode is SINGLE/DOUBLE RATE. */
379 		} else {
380 			/* Check extended token bucket. */
381 			if (hinfo->te - len >= 0 && col <= QOS_COLOR_YELLOW) {
382 				/* This packet is yellow */
383 				++hinfo->stats.yellow_pkts;
384 				hinfo->te -= len;
385 				NG_CAR_PERFORM_MATCH_ACTION(
386 				    hinfo->conf.yellow_action,
387 				    QOS_COLOR_YELLOW);
388 			} else {
389 				/* This packet is red */
390 				++hinfo->stats.red_pkts;
391 				NG_CAR_PERFORM_MATCH_ACTION(
392 				    hinfo->conf.red_action,
393 				    QOS_COLOR_RED);
394 			}
395 		}
396 	}
397 
398 #undef NG_CAR_PERFORM_MATCH_ACTION
399 
400 	NG_FWD_ITEM_HOOK(error, item, hinfo->dest);
401 	if (error != 0)
402 		++hinfo->stats.errors;
403 	++hinfo->stats.passed_pkts;
404 
405 	return (error);
406 }
407 
408 /*
409  * Receive a control message.
410  */
411 static int
412 ng_car_rcvmsg(node_p node, item_p item, hook_p lasthook)
413 {
414 	const priv_p priv = NG_NODE_PRIVATE(node);
415 	struct ng_mesg *resp = NULL;
416 	int error = 0;
417 	struct ng_mesg *msg;
418 
419 	NGI_GET_MSG(item, msg);
420 	switch (msg->header.typecookie) {
421 	case NGM_CAR_COOKIE:
422 		switch (msg->header.cmd) {
423 		case NGM_CAR_GET_STATS:
424 		case NGM_CAR_GETCLR_STATS:
425 			{
426 				struct ng_car_bulkstats *bstats;
427 
428 				NG_MKRESPONSE(resp, msg,
429 					sizeof(*bstats), M_NOWAIT);
430 				if (resp == NULL) {
431 					error = ENOMEM;
432 					break;
433 				}
434 				bstats = (struct ng_car_bulkstats *)resp->data;
435 
436 				bcopy(&priv->upper.stats, &bstats->downstream,
437 				    sizeof(bstats->downstream));
438 				bcopy(&priv->lower.stats, &bstats->upstream,
439 				    sizeof(bstats->upstream));
440 			}
441 			if (msg->header.cmd == NGM_CAR_GET_STATS)
442 				break;
443 		case NGM_CAR_CLR_STATS:
444 			bzero(&priv->upper.stats,
445 				sizeof(priv->upper.stats));
446 			bzero(&priv->lower.stats,
447 				sizeof(priv->lower.stats));
448 			break;
449 		case NGM_CAR_GET_CONF:
450 			{
451 				struct ng_car_bulkconf *bconf;
452 
453 				NG_MKRESPONSE(resp, msg,
454 					sizeof(*bconf), M_NOWAIT);
455 				if (resp == NULL) {
456 					error = ENOMEM;
457 					break;
458 				}
459 				bconf = (struct ng_car_bulkconf *)resp->data;
460 
461 				bcopy(&priv->upper.conf, &bconf->downstream,
462 				    sizeof(bconf->downstream));
463 				bcopy(&priv->lower.conf, &bconf->upstream,
464 				    sizeof(bconf->upstream));
465 				/* Convert internal 1/(8*128) of pps into pps */
466 				if (bconf->downstream.opt & NG_CAR_COUNT_PACKETS) {
467 				    bconf->downstream.cir /= 1024;
468 				    bconf->downstream.pir /= 1024;
469 				    bconf->downstream.cbs /= 128;
470 				    bconf->downstream.ebs /= 128;
471 				}
472 				if (bconf->upstream.opt & NG_CAR_COUNT_PACKETS) {
473 				    bconf->upstream.cir /= 1024;
474 				    bconf->upstream.pir /= 1024;
475 				    bconf->upstream.cbs /= 128;
476 				    bconf->upstream.ebs /= 128;
477 				}
478 			}
479 			break;
480 		case NGM_CAR_SET_CONF:
481 			{
482 				struct ng_car_bulkconf *const bconf =
483 				(struct ng_car_bulkconf *)msg->data;
484 
485 				/* Check for invalid or illegal config. */
486 				if (msg->header.arglen != sizeof(*bconf)) {
487 					error = EINVAL;
488 					break;
489 				}
490 				/* Convert pps into internal 1/(8*128) of pps */
491 				if (bconf->downstream.opt & NG_CAR_COUNT_PACKETS) {
492 				    bconf->downstream.cir *= 1024;
493 				    bconf->downstream.pir *= 1024;
494 				    bconf->downstream.cbs *= 128;
495 				    bconf->downstream.ebs *= 128;
496 				}
497 				if (bconf->upstream.opt & NG_CAR_COUNT_PACKETS) {
498 				    bconf->upstream.cir *= 1024;
499 				    bconf->upstream.pir *= 1024;
500 				    bconf->upstream.cbs *= 128;
501 				    bconf->upstream.ebs *= 128;
502 				}
503 				if ((bconf->downstream.cir > 1000000000) ||
504 				    (bconf->downstream.pir > 1000000000) ||
505 				    (bconf->upstream.cir > 1000000000) ||
506 				    (bconf->upstream.pir > 1000000000) ||
507 				    (bconf->downstream.cbs == 0 &&
508 					bconf->downstream.ebs == 0) ||
509 				    (bconf->upstream.cbs == 0 &&
510 					bconf->upstream.ebs == 0))
511 				{
512 					error = EINVAL;
513 					break;
514 				}
515 				if ((bconf->upstream.mode == NG_CAR_SHAPE) &&
516 				    (bconf->upstream.cir == 0)) {
517 					error = EINVAL;
518 					break;
519 				}
520 				if ((bconf->downstream.mode == NG_CAR_SHAPE) &&
521 				    (bconf->downstream.cir == 0)) {
522 					error = EINVAL;
523 					break;
524 				}
525 
526 				/* Copy downstream config. */
527 				bcopy(&bconf->downstream, &priv->upper.conf,
528 				    sizeof(priv->upper.conf));
529     				priv->upper.tc = priv->upper.conf.cbs;
530 				if (priv->upper.conf.mode == NG_CAR_RED ||
531 				    priv->upper.conf.mode == NG_CAR_SHAPE) {
532 					priv->upper.te = 0;
533 				} else {
534 					priv->upper.te = priv->upper.conf.ebs;
535 				}
536 
537 				/* Copy upstream config. */
538 				bcopy(&bconf->upstream, &priv->lower.conf,
539 				    sizeof(priv->lower.conf));
540     				priv->lower.tc = priv->lower.conf.cbs;
541 				if (priv->lower.conf.mode == NG_CAR_RED ||
542 				    priv->lower.conf.mode == NG_CAR_SHAPE) {
543 					priv->lower.te = 0;
544 				} else {
545 					priv->lower.te = priv->lower.conf.ebs;
546 				}
547 			}
548 			break;
549 		default:
550 			error = EINVAL;
551 			break;
552 		}
553 		break;
554 	default:
555 		error = EINVAL;
556 		break;
557 	}
558 	NG_RESPOND_MSG(error, node, item, resp);
559 	NG_FREE_MSG(msg);
560 	return (error);
561 }
562 
563 /*
564  * Do local shutdown processing.
565  */
566 static int
567 ng_car_shutdown(node_p node)
568 {
569 	const priv_p priv = NG_NODE_PRIVATE(node);
570 
571 	ng_uncallout(&priv->upper.q_callout, node);
572 	ng_uncallout(&priv->lower.q_callout, node);
573 	mtx_destroy(&priv->upper.q_mtx);
574 	mtx_destroy(&priv->lower.q_mtx);
575 	NG_NODE_UNREF(priv->node);
576 	free(priv, M_NETGRAPH);
577 	return (0);
578 }
579 
580 /*
581  * Hook disconnection.
582  *
583  * For this type, removal of the last link destroys the node.
584  */
585 static int
586 ng_car_disconnect(hook_p hook)
587 {
588 	struct hookinfo *const hinfo = NG_HOOK_PRIVATE(hook);
589 	const node_p node = NG_HOOK_NODE(hook);
590 	const priv_p priv = NG_NODE_PRIVATE(node);
591 
592 	if (hinfo) {
593 		/* Purge queue if not empty. */
594 		while (hinfo->q_first != hinfo->q_last) {
595 			NG_FREE_M(hinfo->q[hinfo->q_first]);
596 			hinfo->q_first++;
597 			if (hinfo->q_first >= NG_CAR_QUEUE_SIZE)
598 		    		hinfo->q_first = 0;
599 		}
600 		/* Remove hook refs. */
601 		if (hinfo->hook == priv->upper.hook)
602 			priv->lower.dest = NULL;
603 		else
604 			priv->upper.dest = NULL;
605 		hinfo->hook = NULL;
606 	}
607 	/* Already shutting down? */
608 	if ((NG_NODE_NUMHOOKS(NG_HOOK_NODE(hook)) == 0)
609 	    && (NG_NODE_IS_VALID(NG_HOOK_NODE(hook))))
610 		ng_rmnode_self(NG_HOOK_NODE(hook));
611 	return (0);
612 }
613 
614 /*
615  * Hook's token buckets refillment.
616  */
617 static void
618 ng_car_refillhook(struct hookinfo *h)
619 {
620 	struct bintime newt, deltat;
621 	unsigned int deltat_us;
622 
623 	/* Get current time. */
624 	getbinuptime(&newt);
625 
626 	/* Get time delta since last refill. */
627 	deltat = newt;
628 	bintime_sub(&deltat, &h->lastRefill);
629 
630 	/* Time must go forward. */
631 	if (deltat.sec < 0) {
632 	    h->lastRefill = newt;
633 	    return;
634 	}
635 
636 	/* But not too far forward. */
637 	if (deltat.sec >= 1000) {
638 	    deltat_us = (1000 << 20);
639 	} else {
640 	    /* convert bintime to the 1/(2^20) of sec */
641 	    deltat_us = (deltat.sec << 20) + (deltat.frac >> 44);
642 	}
643 
644 	if (h->conf.mode == NG_CAR_SINGLE_RATE) {
645 		int64_t	delta;
646 		/* Refill committed token bucket. */
647 		h->tc += (h->conf.cir * deltat_us) >> 23;
648 		delta = h->tc - h->conf.cbs;
649 		if (delta > 0) {
650 			h->tc = h->conf.cbs;
651 
652 			/* Refill exceeded token bucket. */
653 			h->te += delta;
654 			if (h->te > ((int64_t)h->conf.ebs))
655 				h->te = h->conf.ebs;
656 		}
657 
658 	} else if (h->conf.mode == NG_CAR_DOUBLE_RATE) {
659 		/* Refill committed token bucket. */
660 		h->tc += (h->conf.cir * deltat_us) >> 23;
661 		if (h->tc > ((int64_t)h->conf.cbs))
662 			h->tc = h->conf.cbs;
663 
664 		/* Refill peak token bucket. */
665 		h->te += (h->conf.pir * deltat_us) >> 23;
666 		if (h->te > ((int64_t)h->conf.ebs))
667 			h->te = h->conf.ebs;
668 
669 	} else { /* RED or SHAPE mode. */
670 		/* Refill committed token bucket. */
671 		h->tc += (h->conf.cir * deltat_us) >> 23;
672 		if (h->tc > ((int64_t)h->conf.cbs))
673 			h->tc = h->conf.cbs;
674 	}
675 
676 	/* Remember this moment. */
677 	h->lastRefill = newt;
678 }
679 
680 /*
681  * Schedule callout when we will have required tokens.
682  */
683 static void
684 ng_car_schedule(struct hookinfo *hinfo)
685 {
686 	int 	delay;
687 
688 	delay = (-(hinfo->tc)) * hz * 8 / hinfo->conf.cir + 1;
689 
690 	ng_callout(&hinfo->q_callout, NG_HOOK_NODE(hinfo->hook), hinfo->hook,
691 	    delay, &ng_car_q_event, NULL, 0);
692 }
693 
694 /*
695  * Queue processing callout handler.
696  */
697 void
698 ng_car_q_event(node_p node, hook_p hook, void *arg, int arg2)
699 {
700 	struct hookinfo	*hinfo = NG_HOOK_PRIVATE(hook);
701 	struct mbuf 	*m;
702 	int		error;
703 
704 	/* Refill tokens for time we have slept. */
705 	ng_car_refillhook(hinfo);
706 
707 	/* If we have some tokens */
708 	while (hinfo->tc >= 0) {
709 		/* Send packet. */
710 		m = hinfo->q[hinfo->q_first];
711 		NG_SEND_DATA_ONLY(error, hinfo->dest, m);
712 		if (error != 0)
713 			++hinfo->stats.errors;
714 		++hinfo->stats.passed_pkts;
715 
716 		/* Get next one. */
717 		hinfo->q_first++;
718 		if (hinfo->q_first >= NG_CAR_QUEUE_SIZE)
719 			hinfo->q_first = 0;
720 
721 		/* Stop if none left. */
722 		if (hinfo->q_first == hinfo->q_last)
723 			break;
724 
725 		/* If we have more packet, try it. */
726 		m = hinfo->q[hinfo->q_first];
727 		if (hinfo->conf.opt & NG_CAR_COUNT_PACKETS) {
728 			hinfo->tc -= 128;
729 		} else {
730 			hinfo->tc -= m->m_pkthdr.len;
731 		}
732 	}
733 
734 	/* If something left */
735 	if (hinfo->q_first != hinfo->q_last)
736 		/* Schedule queue processing. */
737 		ng_car_schedule(hinfo);
738 }
739 
740 /*
741  * Enqueue packet.
742  */
743 static void
744 ng_car_enqueue(struct hookinfo *hinfo, item_p item)
745 {
746 	struct mbuf 	   *m;
747 	int		   len;
748 	struct m_qos_color *colp;
749 	enum qos_color	   col;
750 
751 	NGI_GET_M(item, m);
752 	NG_FREE_ITEM(item);
753 
754 	/* Determine current color of the packet (default green) */
755 	colp = (void *)m_tag_locate(m, M_QOS_COOKIE, M_QOS_COLOR, NULL);
756 	if ((hinfo->conf.opt & NG_CAR_COLOR_AWARE) && (colp != NULL))
757 	    col = colp->color;
758 	else
759 	    col = QOS_COLOR_GREEN;
760 
761 	/* Lock queue mutex. */
762 	mtx_lock(&hinfo->q_mtx);
763 
764 	/* Calculate used queue length. */
765 	len = hinfo->q_last - hinfo->q_first;
766 	if (len < 0)
767 		len += NG_CAR_QUEUE_SIZE;
768 
769 	/* If queue is overflowed or we have no RED tokens. */
770 	if ((len >= (NG_CAR_QUEUE_SIZE - 1)) ||
771 	    (hinfo->te + len >= NG_CAR_QUEUE_SIZE) ||
772 	    (col >= QOS_COLOR_RED)) {
773 		/* Drop packet. */
774 		++hinfo->stats.red_pkts;
775 		++hinfo->stats.dropped_pkts;
776 		NG_FREE_M(m);
777 
778 		hinfo->te = 0;
779 	} else {
780 		/* This packet is yellow. */
781 		++hinfo->stats.yellow_pkts;
782 
783 		/* Enqueue packet. */
784 		hinfo->q[hinfo->q_last] = m;
785 		hinfo->q_last++;
786 		if (hinfo->q_last >= NG_CAR_QUEUE_SIZE)
787 			hinfo->q_last = 0;
788 
789 		/* Use RED tokens. */
790 		if (len > NG_CAR_QUEUE_MIN_TH)
791 			hinfo->te += len - NG_CAR_QUEUE_MIN_TH;
792 
793 		/* If this is a first packet in the queue. */
794 		if (len == 0) {
795 			if (hinfo->conf.opt & NG_CAR_COUNT_PACKETS) {
796 				hinfo->tc -= 128;
797 			} else {
798 				hinfo->tc -= m->m_pkthdr.len;
799 			}
800 
801 			/* Schedule queue processing. */
802 			ng_car_schedule(hinfo);
803 		}
804 	}
805 
806 	/* Unlock queue mutex. */
807 	mtx_unlock(&hinfo->q_mtx);
808 }
809