xref: /freebsd/sys/netgraph/ng_car.c (revision 7447ca0eb235974642312b9555caec00b57d8fc1)
1 /*-
2  * Copyright (c) 2005 Nuno Antunes <nuno.antunes@gmail.com>
3  * Copyright (c) 2007 Alexander Motin <mav@freebsd.org>
4  * All rights reserved.
5  *
6  * Redistribution and use in source and binary forms, with or without
7  * modification, are permitted provided that the following conditions
8  * are met:
9  * 1. Redistributions of source code must retain the above copyright
10  *    notice, this list of conditions and the following 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 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 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  * $FreeBSD$
28  */
29 
30 /*
31  * ng_car - An implementation of committed access rate for netgraph
32  *
33  * TODO:
34  *	- Sanitize input config values (impose some limits)
35  *	- Implement internal packet painting (possibly using mbuf tags)
36  *	- Implement color-aware mode
37  *	- Implement DSCP marking for IPv4
38  */
39 
40 #include <sys/param.h>
41 #include <sys/errno.h>
42 #include <sys/kernel.h>
43 #include <sys/malloc.h>
44 #include <sys/mbuf.h>
45 
46 #include <netgraph/ng_message.h>
47 #include <netgraph/ng_parse.h>
48 #include <netgraph/netgraph.h>
49 #include <netgraph/ng_car.h>
50 
51 #define NG_CAR_QUEUE_SIZE	100	/* Maximum queue size for SHAPE mode */
52 #define NG_CAR_QUEUE_MIN_TH	8	/* Minimum RED threshold for SHAPE mode */
53 
54 /* Hook private info */
55 struct hookinfo {
56 	hook_p		hook;		/* this (source) hook */
57 	hook_p		dest;		/* destination hook */
58 
59 	int64_t 	tc;		/* committed token bucket counter */
60 	int64_t 	te;		/* exceeded/peak token bucket counter */
61 	struct bintime	lastRefill;	/* last token refill time */
62 
63 	struct ng_car_hookconf conf;	/* hook configuration */
64 	struct ng_car_hookstats stats;	/* hook stats */
65 
66 	struct mbuf	*q[NG_CAR_QUEUE_SIZE];	/* circular packet queue */
67 	u_int		q_first;	/* first queue element */
68 	u_int		q_last;		/* last queue element */
69 	struct callout	q_callout;	/* periodic queue processing routine */
70 	struct mtx	q_mtx;		/* queue mutex */
71 };
72 
73 /* Private information for each node instance */
74 struct privdata {
75 	node_p node;				/* the node itself */
76 	struct hookinfo upper;			/* hook to upper layers */
77 	struct hookinfo lower;			/* hook to lower layers */
78 };
79 typedef struct privdata *priv_p;
80 
81 static ng_constructor_t	ng_car_constructor;
82 static ng_rcvmsg_t	ng_car_rcvmsg;
83 static ng_shutdown_t	ng_car_shutdown;
84 static ng_newhook_t	ng_car_newhook;
85 static ng_rcvdata_t	ng_car_rcvdata;
86 static ng_disconnect_t	ng_car_disconnect;
87 
88 static void	ng_car_refillhook(struct hookinfo *h);
89 static void	ng_car_schedule(struct hookinfo *h);
90 void		ng_car_q_event(node_p node, hook_p hook, void *arg, int arg2);
91 static void	ng_car_enqueue(struct hookinfo *h, item_p item);
92 
93 /* Parse type for struct ng_car_hookstats */
94 static const struct ng_parse_struct_field ng_car_hookstats_type_fields[]
95 	= NG_CAR_HOOKSTATS;
96 static const struct ng_parse_type ng_car_hookstats_type = {
97 	&ng_parse_struct_type,
98 	&ng_car_hookstats_type_fields
99 };
100 
101 /* Parse type for struct ng_car_bulkstats */
102 static const struct ng_parse_struct_field ng_car_bulkstats_type_fields[]
103 	= NG_CAR_BULKSTATS(&ng_car_hookstats_type);
104 static const struct ng_parse_type ng_car_bulkstats_type = {
105 	&ng_parse_struct_type,
106 	&ng_car_bulkstats_type_fields
107 };
108 
109 /* Parse type for struct ng_car_hookconf */
110 static const struct ng_parse_struct_field ng_car_hookconf_type_fields[]
111 	= NG_CAR_HOOKCONF;
112 static const struct ng_parse_type ng_car_hookconf_type = {
113 	&ng_parse_struct_type,
114 	&ng_car_hookconf_type_fields
115 };
116 
117 /* Parse type for struct ng_car_bulkconf */
118 static const struct ng_parse_struct_field ng_car_bulkconf_type_fields[]
119 	= NG_CAR_BULKCONF(&ng_car_hookconf_type);
120 static const struct ng_parse_type ng_car_bulkconf_type = {
121 	&ng_parse_struct_type,
122 	&ng_car_bulkconf_type_fields
123 };
124 
125 /* Command list */
126 static struct ng_cmdlist ng_car_cmdlist[] = {
127 	{
128 	  NGM_CAR_COOKIE,
129 	  NGM_CAR_GET_STATS,
130 	  "getstats",
131 	  NULL,
132 	  &ng_car_bulkstats_type,
133 	},
134 	{
135 	  NGM_CAR_COOKIE,
136 	  NGM_CAR_CLR_STATS,
137 	  "clrstats",
138 	  NULL,
139 	  NULL,
140 	},
141 	{
142 	  NGM_CAR_COOKIE,
143 	  NGM_CAR_GETCLR_STATS,
144 	  "getclrstats",
145 	  NULL,
146 	  &ng_car_bulkstats_type,
147 	},
148 
149 	{
150 	  NGM_CAR_COOKIE,
151 	  NGM_CAR_GET_CONF,
152 	  "getconf",
153 	  NULL,
154 	  &ng_car_bulkconf_type,
155 	},
156 	{
157 	  NGM_CAR_COOKIE,
158 	  NGM_CAR_SET_CONF,
159 	  "setconf",
160 	  &ng_car_bulkconf_type,
161 	  NULL,
162 	},
163 	{ 0 }
164 };
165 
166 /* Netgraph node type descriptor */
167 static struct ng_type ng_car_typestruct = {
168 	.version =	NG_ABI_VERSION,
169 	.name =		NG_CAR_NODE_TYPE,
170 	.constructor =	ng_car_constructor,
171 	.rcvmsg =	ng_car_rcvmsg,
172 	.shutdown =	ng_car_shutdown,
173 	.newhook =	ng_car_newhook,
174 	.rcvdata =	ng_car_rcvdata,
175 	.disconnect =	ng_car_disconnect,
176 	.cmdlist =	ng_car_cmdlist,
177 };
178 NETGRAPH_INIT(car, &ng_car_typestruct);
179 
180 /*
181  * Node constructor
182  */
183 static int
184 ng_car_constructor(node_p node)
185 {
186 	priv_p priv;
187 
188 	/* Initialize private descriptor. */
189 	priv = malloc(sizeof(*priv), M_NETGRAPH, M_WAITOK | M_ZERO);
190 
191 	NG_NODE_SET_PRIVATE(node, priv);
192 	priv->node = node;
193 
194 	/*
195 	 * Arbitrary default values
196 	 */
197 
198 	priv->upper.hook = NULL;
199 	priv->upper.dest = NULL;
200 	priv->upper.tc = priv->upper.conf.cbs = NG_CAR_CBS_MIN;
201 	priv->upper.te = priv->upper.conf.ebs = NG_CAR_EBS_MIN;
202 	priv->upper.conf.cir = NG_CAR_CIR_DFLT;
203 	priv->upper.conf.green_action = NG_CAR_ACTION_FORWARD;
204 	priv->upper.conf.yellow_action = NG_CAR_ACTION_FORWARD;
205 	priv->upper.conf.red_action = NG_CAR_ACTION_DROP;
206 	priv->upper.conf.mode = 0;
207 	getbinuptime(&priv->upper.lastRefill);
208 	priv->upper.q_first = 0;
209 	priv->upper.q_last = 0;
210 	ng_callout_init(&priv->upper.q_callout);
211 	mtx_init(&priv->upper.q_mtx, "ng_car_u", NULL, MTX_DEF);
212 
213 	priv->lower.hook = NULL;
214 	priv->lower.dest = NULL;
215 	priv->lower.tc = priv->lower.conf.cbs = NG_CAR_CBS_MIN;
216 	priv->lower.te = priv->lower.conf.ebs = NG_CAR_EBS_MIN;
217 	priv->lower.conf.cir = NG_CAR_CIR_DFLT;
218 	priv->lower.conf.green_action = NG_CAR_ACTION_FORWARD;
219 	priv->lower.conf.yellow_action = NG_CAR_ACTION_FORWARD;
220 	priv->lower.conf.red_action = NG_CAR_ACTION_DROP;
221 	priv->lower.conf.mode = 0;
222 	priv->lower.lastRefill = priv->upper.lastRefill;
223 	priv->lower.q_first = 0;
224 	priv->lower.q_last = 0;
225 	ng_callout_init(&priv->lower.q_callout);
226 	mtx_init(&priv->lower.q_mtx, "ng_car_l", NULL, MTX_DEF);
227 
228 	return (0);
229 }
230 
231 /*
232  * Add a hook.
233  */
234 static int
235 ng_car_newhook(node_p node, hook_p hook, const char *name)
236 {
237 	const priv_p priv = NG_NODE_PRIVATE(node);
238 
239 	if (strcmp(name, NG_CAR_HOOK_LOWER) == 0) {
240 		priv->lower.hook = hook;
241 		priv->upper.dest = hook;
242 		bzero(&priv->lower.stats, sizeof(priv->lower.stats));
243 		NG_HOOK_SET_PRIVATE(hook, &priv->lower);
244 	} else if (strcmp(name, NG_CAR_HOOK_UPPER) == 0) {
245 		priv->upper.hook = hook;
246 		priv->lower.dest = hook;
247 		bzero(&priv->upper.stats, sizeof(priv->upper.stats));
248 		NG_HOOK_SET_PRIVATE(hook, &priv->upper);
249 	} else
250 		return (EINVAL);
251 	return(0);
252 }
253 
254 /*
255  * Data has arrived.
256  */
257 static int
258 ng_car_rcvdata(hook_p hook, item_p item )
259 {
260 	struct hookinfo *const hinfo = NG_HOOK_PRIVATE(hook);
261 	struct mbuf *m;
262 	int error = 0;
263 	u_int len;
264 
265 	/* If queue is not empty now then enqueue packet. */
266 	if (hinfo->q_first != hinfo->q_last) {
267 		ng_car_enqueue(hinfo, item);
268 		return (0);
269 	}
270 
271 	m = NGI_M(item);
272 
273 #define NG_CAR_PERFORM_MATCH_ACTION(a)			\
274 	do {						\
275 		switch (a) {				\
276 		case NG_CAR_ACTION_FORWARD:		\
277 			/* Do nothing. */		\
278 			break;				\
279 		case NG_CAR_ACTION_MARK:		\
280 			/* XXX find a way to mark packets (mbuf tag?) */ \
281 			++hinfo->stats.errors;		\
282 			break;				\
283 		case NG_CAR_ACTION_DROP:		\
284 		default:				\
285 			/* Drop packet and return. */	\
286 			NG_FREE_ITEM(item);		\
287 			++hinfo->stats.droped_pkts;	\
288 			return (0);			\
289 		}					\
290 	} while (0)
291 
292 	/* Packet is counted as 128 tokens for better resolution */
293 	if (hinfo->conf.opt & NG_CAR_COUNT_PACKETS) {
294 		len = 128;
295 	} else {
296 		len = m->m_pkthdr.len;
297 	}
298 
299 	/* Check committed token bucket. */
300 	if (hinfo->tc - len >= 0) {
301 		/* This packet is green. */
302 		++hinfo->stats.green_pkts;
303 		hinfo->tc -= len;
304 		NG_CAR_PERFORM_MATCH_ACTION(hinfo->conf.green_action);
305 	} else {
306 
307 		/* Refill only if not green without it. */
308 		ng_car_refillhook(hinfo);
309 
310 		 /* Check committed token bucket again after refill. */
311 		if (hinfo->tc - len >= 0) {
312 			/* This packet is green */
313 			++hinfo->stats.green_pkts;
314 			hinfo->tc -= len;
315 			NG_CAR_PERFORM_MATCH_ACTION(hinfo->conf.green_action);
316 
317 		/* If not green and mode is SHAPE, enqueue packet. */
318 		} else if (hinfo->conf.mode == NG_CAR_SHAPE) {
319 			ng_car_enqueue(hinfo, item);
320 			return (0);
321 
322 		/* If not green and mode is RED, calculate probability. */
323 		} else if (hinfo->conf.mode == NG_CAR_RED) {
324 			/* Is packet is bigger then extended burst? */
325 			if (len - (hinfo->tc - len) > hinfo->conf.ebs) {
326 				/* This packet is definitely red. */
327 				++hinfo->stats.red_pkts;
328 				hinfo->te = 0;
329 				NG_CAR_PERFORM_MATCH_ACTION(hinfo->conf.red_action);
330 
331 			/* Use token bucket to simulate RED-like drop
332 			   probability. */
333 			} else if (hinfo->te + (len - hinfo->tc) <
334 			    hinfo->conf.ebs) {
335 				/* This packet is yellow */
336 				++hinfo->stats.yellow_pkts;
337 				hinfo->te += len - hinfo->tc;
338 				/* Go to negative tokens. */
339 				hinfo->tc -= len;
340 				NG_CAR_PERFORM_MATCH_ACTION(hinfo->conf.yellow_action);
341 			} else {
342 				/* This packet is probably red. */
343 				++hinfo->stats.red_pkts;
344 				hinfo->te = 0;
345 				NG_CAR_PERFORM_MATCH_ACTION(hinfo->conf.red_action);
346 			}
347 		/* If not green and mode is SINGLE/DOUBLE RATE. */
348 		} else {
349 			/* Check extended token bucket. */
350 			if (hinfo->te - len >= 0) {
351 				/* This packet is yellow */
352 				++hinfo->stats.yellow_pkts;
353 				hinfo->te -= len;
354 				NG_CAR_PERFORM_MATCH_ACTION(hinfo->conf.yellow_action);
355 			} else {
356 				/* This packet is red */
357 				++hinfo->stats.red_pkts;
358 				NG_CAR_PERFORM_MATCH_ACTION(hinfo->conf.red_action);
359 			}
360 		}
361 	}
362 
363 #undef NG_CAR_PERFORM_MATCH_ACTION
364 
365 	NG_FWD_ITEM_HOOK(error, item, hinfo->dest);
366 	if (error != 0)
367 		++hinfo->stats.errors;
368 	++hinfo->stats.passed_pkts;
369 
370 	return (error);
371 }
372 
373 /*
374  * Receive a control message.
375  */
376 static int
377 ng_car_rcvmsg(node_p node, item_p item, hook_p lasthook)
378 {
379 	const priv_p priv = NG_NODE_PRIVATE(node);
380 	struct ng_mesg *resp = NULL;
381 	int error = 0;
382 	struct ng_mesg *msg;
383 
384 	NGI_GET_MSG(item, msg);
385 	switch (msg->header.typecookie) {
386 	case NGM_CAR_COOKIE:
387 		switch (msg->header.cmd) {
388 		case NGM_CAR_GET_STATS:
389 		case NGM_CAR_GETCLR_STATS:
390 			{
391 				struct ng_car_bulkstats *bstats;
392 
393 				NG_MKRESPONSE(resp, msg,
394 					sizeof(*bstats), M_NOWAIT);
395 				if (resp == NULL) {
396 					error = ENOMEM;
397 					break;
398 				}
399 				bstats = (struct ng_car_bulkstats *)resp->data;
400 
401 				bcopy(&priv->upper.stats, &bstats->downstream,
402 				    sizeof(bstats->downstream));
403 				bcopy(&priv->lower.stats, &bstats->upstream,
404 				    sizeof(bstats->upstream));
405 			}
406 			if (msg->header.cmd == NGM_CAR_GET_STATS)
407 				break;
408 		case NGM_CAR_CLR_STATS:
409 			bzero(&priv->upper.stats,
410 				sizeof(priv->upper.stats));
411 			bzero(&priv->lower.stats,
412 				sizeof(priv->lower.stats));
413 			break;
414 		case NGM_CAR_GET_CONF:
415 			{
416 				struct ng_car_bulkconf *bconf;
417 
418 				NG_MKRESPONSE(resp, msg,
419 					sizeof(*bconf), M_NOWAIT);
420 				if (resp == NULL) {
421 					error = ENOMEM;
422 					break;
423 				}
424 				bconf = (struct ng_car_bulkconf *)resp->data;
425 
426 				bcopy(&priv->upper.conf, &bconf->downstream,
427 				    sizeof(bconf->downstream));
428 				bcopy(&priv->lower.conf, &bconf->upstream,
429 				    sizeof(bconf->upstream));
430 				/* Convert internal 1/(8*128) of pps into pps */
431 				if (bconf->downstream.opt & NG_CAR_COUNT_PACKETS) {
432 				    bconf->downstream.cir /= 1024;
433 				    bconf->downstream.pir /= 1024;
434 				    bconf->downstream.cbs /= 128;
435 				    bconf->downstream.ebs /= 128;
436 				}
437 				if (bconf->upstream.opt & NG_CAR_COUNT_PACKETS) {
438 				    bconf->upstream.cir /= 1024;
439 				    bconf->upstream.pir /= 1024;
440 				    bconf->upstream.cbs /= 128;
441 				    bconf->upstream.ebs /= 128;
442 				}
443 			}
444 			break;
445 		case NGM_CAR_SET_CONF:
446 			{
447 				struct ng_car_bulkconf *const bconf =
448 				(struct ng_car_bulkconf *)msg->data;
449 
450 				/* Check for invalid or illegal config. */
451 				if (msg->header.arglen != sizeof(*bconf)) {
452 					error = EINVAL;
453 					break;
454 				}
455 				/* Convert pps into internal 1/(8*128) of pps */
456 				if (bconf->downstream.opt & NG_CAR_COUNT_PACKETS) {
457 				    bconf->downstream.cir *= 1024;
458 				    bconf->downstream.pir *= 1024;
459 				    bconf->downstream.cbs *= 125;
460 				    bconf->downstream.ebs *= 125;
461 				}
462 				if (bconf->upstream.opt & NG_CAR_COUNT_PACKETS) {
463 				    bconf->upstream.cir *= 1024;
464 				    bconf->upstream.pir *= 1024;
465 				    bconf->upstream.cbs *= 125;
466 				    bconf->upstream.ebs *= 125;
467 				}
468 				if ((bconf->downstream.cir > 1000000000) ||
469 				    (bconf->downstream.pir > 1000000000) ||
470 				    (bconf->upstream.cir > 1000000000) ||
471 				    (bconf->upstream.pir > 1000000000) ||
472 				    (bconf->downstream.cbs == 0 &&
473 					bconf->downstream.ebs == 0) ||
474 				    (bconf->upstream.cbs == 0 &&
475 					bconf->upstream.ebs == 0))
476 				{
477 					error = EINVAL;
478 					break;
479 				}
480 				if ((bconf->upstream.mode == NG_CAR_SHAPE) &&
481 				    (bconf->upstream.cir == 0)) {
482 					error = EINVAL;
483 					break;
484 				}
485 				if ((bconf->downstream.mode == NG_CAR_SHAPE) &&
486 				    (bconf->downstream.cir == 0)) {
487 					error = EINVAL;
488 					break;
489 				}
490 
491 				/* Copy downstream config. */
492 				bcopy(&bconf->downstream, &priv->upper.conf,
493 				    sizeof(priv->upper.conf));
494     				priv->upper.tc = priv->upper.conf.cbs;
495 				if (priv->upper.conf.mode == NG_CAR_RED ||
496 				    priv->upper.conf.mode == NG_CAR_SHAPE) {
497 					priv->upper.te = 0;
498 				} else {
499 					priv->upper.te = priv->upper.conf.ebs;
500 				}
501 
502 				/* Copy upstream config. */
503 				bcopy(&bconf->upstream, &priv->lower.conf,
504 				    sizeof(priv->lower.conf));
505     				priv->lower.tc = priv->lower.conf.cbs;
506 				if (priv->lower.conf.mode == NG_CAR_RED ||
507 				    priv->lower.conf.mode == NG_CAR_SHAPE) {
508 					priv->lower.te = 0;
509 				} else {
510 					priv->lower.te = priv->lower.conf.ebs;
511 				}
512 			}
513 			break;
514 		default:
515 			error = EINVAL;
516 			break;
517 		}
518 		break;
519 	default:
520 		error = EINVAL;
521 		break;
522 	}
523 	NG_RESPOND_MSG(error, node, item, resp);
524 	NG_FREE_MSG(msg);
525 	return (error);
526 }
527 
528 /*
529  * Do local shutdown processing.
530  */
531 static int
532 ng_car_shutdown(node_p node)
533 {
534 	const priv_p priv = NG_NODE_PRIVATE(node);
535 
536 	ng_uncallout(&priv->upper.q_callout, node);
537 	ng_uncallout(&priv->lower.q_callout, node);
538 	mtx_destroy(&priv->upper.q_mtx);
539 	mtx_destroy(&priv->lower.q_mtx);
540 	NG_NODE_UNREF(priv->node);
541 	free(priv, M_NETGRAPH);
542 	return (0);
543 }
544 
545 /*
546  * Hook disconnection.
547  *
548  * For this type, removal of the last link destroys the node.
549  */
550 static int
551 ng_car_disconnect(hook_p hook)
552 {
553 	struct hookinfo *const hinfo = NG_HOOK_PRIVATE(hook);
554 	const node_p node = NG_HOOK_NODE(hook);
555 	const priv_p priv = NG_NODE_PRIVATE(node);
556 
557 	if (hinfo) {
558 		/* Purge queue if not empty. */
559 		while (hinfo->q_first != hinfo->q_last) {
560 			NG_FREE_M(hinfo->q[hinfo->q_first]);
561 			hinfo->q_first++;
562 			if (hinfo->q_first >= NG_CAR_QUEUE_SIZE)
563 		    		hinfo->q_first = 0;
564 		}
565 		/* Remove hook refs. */
566 		if (hinfo->hook == priv->upper.hook)
567 			priv->lower.dest = NULL;
568 		else
569 			priv->upper.dest = NULL;
570 		hinfo->hook = NULL;
571 	}
572 	/* Already shutting down? */
573 	if ((NG_NODE_NUMHOOKS(NG_HOOK_NODE(hook)) == 0)
574 	    && (NG_NODE_IS_VALID(NG_HOOK_NODE(hook))))
575 		ng_rmnode_self(NG_HOOK_NODE(hook));
576 	return (0);
577 }
578 
579 /*
580  * Hook's token buckets refillment.
581  */
582 static void
583 ng_car_refillhook(struct hookinfo *h)
584 {
585 	struct bintime newt, deltat;
586 	unsigned int deltat_us;
587 
588 	/* Get current time. */
589 	getbinuptime(&newt);
590 
591 	/* Get time delta since last refill. */
592 	deltat = newt;
593 	bintime_sub(&deltat, &h->lastRefill);
594 
595 	/* Time must go forward. */
596 	if (deltat.sec < 0) {
597 	    h->lastRefill = newt;
598 	    return;
599 	}
600 
601 	/* But not too far forward. */
602 	if (deltat.sec >= 1000) {
603 	    deltat_us = (1000 << 20);
604 	} else {
605 	    /* convert bintime to the 1/(2^20) of sec */
606 	    deltat_us = (deltat.sec << 20) + (deltat.frac >> 44);
607 	}
608 
609 	if (h->conf.mode == NG_CAR_SINGLE_RATE) {
610 		int64_t	delta;
611 		/* Refill committed token bucket. */
612 		h->tc += (h->conf.cir * deltat_us) >> 23;
613 		delta = h->tc - h->conf.cbs;
614 		if (delta > 0) {
615 			h->tc = h->conf.cbs;
616 
617 			/* Refill exceeded token bucket. */
618 			h->te += delta;
619 			if (h->te > ((int64_t)h->conf.ebs))
620 				h->te = h->conf.ebs;
621 		}
622 
623 	} else if (h->conf.mode == NG_CAR_DOUBLE_RATE) {
624 		/* Refill committed token bucket. */
625 		h->tc += (h->conf.cir * deltat_us) >> 23;
626 		if (h->tc > ((int64_t)h->conf.cbs))
627 			h->tc = h->conf.cbs;
628 
629 		/* Refill peak token bucket. */
630 		h->te += (h->conf.pir * deltat_us) >> 23;
631 		if (h->te > ((int64_t)h->conf.ebs))
632 			h->te = h->conf.ebs;
633 
634 	} else { /* RED or SHAPE mode. */
635 		/* Refill committed token bucket. */
636 		h->tc += (h->conf.cir * deltat_us) >> 23;
637 		if (h->tc > ((int64_t)h->conf.cbs))
638 			h->tc = h->conf.cbs;
639 	}
640 
641 	/* Remember this moment. */
642 	h->lastRefill = newt;
643 }
644 
645 /*
646  * Schedule callout when we will have required tokens.
647  */
648 static void
649 ng_car_schedule(struct hookinfo *hinfo)
650 {
651 	int 	delay;
652 
653 	delay = (-(hinfo->tc)) * hz * 8 / hinfo->conf.cir + 1;
654 
655 	ng_callout(&hinfo->q_callout, NG_HOOK_NODE(hinfo->hook), hinfo->hook,
656 	    delay, &ng_car_q_event, NULL, 0);
657 }
658 
659 /*
660  * Queue processing callout handler.
661  */
662 void
663 ng_car_q_event(node_p node, hook_p hook, void *arg, int arg2)
664 {
665 	struct hookinfo	*hinfo = NG_HOOK_PRIVATE(hook);
666 	struct mbuf 	*m;
667 	int		error;
668 
669 	/* Refill tokens for time we have slept. */
670 	ng_car_refillhook(hinfo);
671 
672 	/* If we have some tokens */
673 	while (hinfo->tc >= 0) {
674 
675 		/* Send packet. */
676 		m = hinfo->q[hinfo->q_first];
677 		NG_SEND_DATA_ONLY(error, hinfo->dest, m);
678 		if (error != 0)
679 			++hinfo->stats.errors;
680 		++hinfo->stats.passed_pkts;
681 
682 		/* Get next one. */
683 		hinfo->q_first++;
684 		if (hinfo->q_first >= NG_CAR_QUEUE_SIZE)
685 			hinfo->q_first = 0;
686 
687 		/* Stop if none left. */
688 		if (hinfo->q_first == hinfo->q_last)
689 			break;
690 
691 		/* If we have more packet, try it. */
692 		m = hinfo->q[hinfo->q_first];
693 		if (hinfo->conf.opt & NG_CAR_COUNT_PACKETS) {
694 			hinfo->tc -= 128;
695 		} else {
696 			hinfo->tc -= m->m_pkthdr.len;
697 		}
698 	}
699 
700 	/* If something left */
701 	if (hinfo->q_first != hinfo->q_last)
702 		/* Schedule queue processing. */
703 		ng_car_schedule(hinfo);
704 }
705 
706 /*
707  * Enqueue packet.
708  */
709 static void
710 ng_car_enqueue(struct hookinfo *hinfo, item_p item)
711 {
712 	struct mbuf 	*m;
713 	int		len;
714 
715 	NGI_GET_M(item, m);
716 	NG_FREE_ITEM(item);
717 
718 	/* Lock queue mutex. */
719 	mtx_lock(&hinfo->q_mtx);
720 
721 	/* Calculate used queue length. */
722 	len = hinfo->q_last - hinfo->q_first;
723 	if (len < 0)
724 		len += NG_CAR_QUEUE_SIZE;
725 
726 	/* If queue is overflowed or we have no RED tokens. */
727 	if ((len >= (NG_CAR_QUEUE_SIZE - 1)) ||
728 	    (hinfo->te + len >= NG_CAR_QUEUE_SIZE)) {
729 		/* Drop packet. */
730 		++hinfo->stats.red_pkts;
731 		++hinfo->stats.droped_pkts;
732 		NG_FREE_M(m);
733 
734 		hinfo->te = 0;
735 	} else {
736 		/* This packet is yellow. */
737 		++hinfo->stats.yellow_pkts;
738 
739 		/* Enqueue packet. */
740 		hinfo->q[hinfo->q_last] = m;
741 		hinfo->q_last++;
742 		if (hinfo->q_last >= NG_CAR_QUEUE_SIZE)
743 			hinfo->q_last = 0;
744 
745 		/* Use RED tokens. */
746 		if (len > NG_CAR_QUEUE_MIN_TH)
747 			hinfo->te += len - NG_CAR_QUEUE_MIN_TH;
748 
749 		/* If this is a first packet in the queue. */
750 		if (len == 0) {
751 			if (hinfo->conf.opt & NG_CAR_COUNT_PACKETS) {
752 				hinfo->tc -= 128;
753 			} else {
754 				hinfo->tc -= m->m_pkthdr.len;
755 			}
756 
757 			/* Schedule queue processing. */
758 			ng_car_schedule(hinfo);
759 		}
760 	}
761 
762 	/* Unlock queue mutex. */
763 	mtx_unlock(&hinfo->q_mtx);
764 }
765