xref: /freebsd/sys/netgraph/ng_car.c (revision 10f0bcab61ef441cb5af32fb706688d8cbd55dc0)
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 commited 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 threshhold 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;		/* commited 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 	int		q_first;	/* first queue element */
68 	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_NOWAIT | M_ZERO);
190 	if (priv == NULL)
191 		return (ENOMEM);
192 
193 	NG_NODE_SET_PRIVATE(node, priv);
194 	priv->node = node;
195 
196 	/*
197 	 * Arbitrary default values
198 	 */
199 
200 	priv->upper.hook = NULL;
201 	priv->upper.dest = NULL;
202 	priv->upper.tc = priv->upper.conf.cbs = NG_CAR_CBS_MIN;
203 	priv->upper.te = priv->upper.conf.ebs = NG_CAR_EBS_MIN;
204 	priv->upper.conf.cir = NG_CAR_CIR_DFLT;
205 	priv->upper.conf.green_action = NG_CAR_ACTION_FORWARD;
206 	priv->upper.conf.yellow_action = NG_CAR_ACTION_FORWARD;
207 	priv->upper.conf.red_action = NG_CAR_ACTION_DROP;
208 	priv->upper.conf.mode = 0;
209 	getbinuptime(&priv->upper.lastRefill);
210 	priv->upper.q_first = 0;
211 	priv->upper.q_last = 0;
212 	ng_callout_init(&priv->upper.q_callout);
213 	mtx_init(&priv->upper.q_mtx, "ng_car_u", NULL, MTX_DEF);
214 
215 	priv->lower.hook = NULL;
216 	priv->lower.dest = NULL;
217 	priv->lower.tc = priv->lower.conf.cbs = NG_CAR_CBS_MIN;
218 	priv->lower.te = priv->lower.conf.ebs = NG_CAR_EBS_MIN;
219 	priv->lower.conf.cir = NG_CAR_CIR_DFLT;
220 	priv->lower.conf.green_action = NG_CAR_ACTION_FORWARD;
221 	priv->lower.conf.yellow_action = NG_CAR_ACTION_FORWARD;
222 	priv->lower.conf.red_action = NG_CAR_ACTION_DROP;
223 	priv->lower.conf.mode = 0;
224 	priv->lower.lastRefill = priv->upper.lastRefill;
225 	priv->lower.q_first = 0;
226 	priv->lower.q_last = 0;
227 	ng_callout_init(&priv->lower.q_callout);
228 	mtx_init(&priv->lower.q_mtx, "ng_car_l", NULL, MTX_DEF);
229 
230 	return (0);
231 }
232 
233 /*
234  * Add a hook.
235  */
236 static int
237 ng_car_newhook(node_p node, hook_p hook, const char *name)
238 {
239 	const priv_p priv = NG_NODE_PRIVATE(node);
240 
241 	if (strcmp(name, NG_CAR_HOOK_LOWER) == 0) {
242 		priv->lower.hook = hook;
243 		priv->upper.dest = hook;
244 		bzero(&priv->lower.stats, sizeof(priv->lower.stats));
245 		NG_HOOK_SET_PRIVATE(hook, &priv->lower);
246 	} else if (strcmp(name, NG_CAR_HOOK_UPPER) == 0) {
247 		priv->upper.hook = hook;
248 		priv->lower.dest = hook;
249 		bzero(&priv->upper.stats, sizeof(priv->upper.stats));
250 		NG_HOOK_SET_PRIVATE(hook, &priv->upper);
251 	} else
252 		return (EINVAL);
253 	return(0);
254 }
255 
256 /*
257  * Data has arrived.
258  */
259 static int
260 ng_car_rcvdata(hook_p hook, item_p item )
261 {
262 	struct hookinfo *const hinfo = NG_HOOK_PRIVATE(hook);
263 	hook_p dest = hinfo->dest;
264 	struct mbuf *m = NULL;
265 	int error = 0;
266 	int len;
267 
268 	/* Node is useless without destination hook. */
269 	if (dest == NULL) {
270 		NG_FREE_ITEM(item);
271 		++hinfo->stats.errors;
272 		return(EINVAL);
273 	}
274 
275 	/* If queue is not empty now then enqueue packet. */
276 	if (hinfo->q_first != hinfo->q_last) {
277 		ng_car_enqueue(hinfo, item);
278 		return (0);
279 	}
280 
281 	m = NGI_M(item);
282 
283 #define NG_CAR_PERFORM_MATCH_ACTION(a)			\
284 	do {						\
285 		switch (a) {				\
286 		case NG_CAR_ACTION_FORWARD:		\
287 			/* Do nothing. */		\
288 			break;				\
289 		case NG_CAR_ACTION_MARK:		\
290 			/* XXX find a way to mark packets (mbuf tag?) */ \
291 			++hinfo->stats.errors;		\
292 			break;				\
293 		case NG_CAR_ACTION_DROP:		\
294 		default:				\
295 			/* Drop packet and return. */	\
296 			NG_FREE_ITEM(item);		\
297 			++hinfo->stats.droped_pkts;	\
298 			return (0);			\
299 		}					\
300 	} while (0)
301 
302 	/* Packet is counted as 128 tokens for better resolution */
303 	if (hinfo->conf.opt & NG_CAR_COUNT_PACKETS) {
304 		len = 128;
305 	} else {
306 		len = m->m_pkthdr.len;
307 	}
308 
309 	/* Check commited token bucket. */
310 	if (hinfo->tc - len >= 0) {
311 		/* This packet is green. */
312 		++hinfo->stats.green_pkts;
313 		hinfo->tc -= len;
314 		NG_CAR_PERFORM_MATCH_ACTION(hinfo->conf.green_action);
315 	} else {
316 
317 		/* Refill only if not green without it. */
318 		ng_car_refillhook(hinfo);
319 
320 		 /* Check commited token bucket again after refill. */
321 		if (hinfo->tc - len >= 0) {
322 			/* This packet is green */
323 			++hinfo->stats.green_pkts;
324 			hinfo->tc -= len;
325 			NG_CAR_PERFORM_MATCH_ACTION(hinfo->conf.green_action);
326 
327 		/* If not green and mode is SHAPE, enqueue packet. */
328 		} else if (hinfo->conf.mode == NG_CAR_SHAPE) {
329 			ng_car_enqueue(hinfo, item);
330 			return (0);
331 
332 		/* If not green and mode is RED, calculate probability. */
333 		} else if (hinfo->conf.mode == NG_CAR_RED) {
334 			/* Is packet is bigger then extended burst? */
335 			if (len - (hinfo->tc - len) > hinfo->conf.ebs) {
336 				/* This packet is definitely red. */
337 				++hinfo->stats.red_pkts;
338 				hinfo->te = 0;
339 				NG_CAR_PERFORM_MATCH_ACTION(hinfo->conf.red_action);
340 
341 			/* Use token bucket to simulate RED-like drop
342 			   probability. */
343 			} else if (hinfo->te + (len - hinfo->tc) <
344 			    hinfo->conf.ebs) {
345 				/* This packet is yellow */
346 				++hinfo->stats.yellow_pkts;
347 				hinfo->te += len - hinfo->tc;
348 				/* Go to negative tokens. */
349 				hinfo->tc -= len;
350 				NG_CAR_PERFORM_MATCH_ACTION(hinfo->conf.yellow_action);
351 			} else {
352 				/* This packet is probaly red. */
353 				++hinfo->stats.red_pkts;
354 				hinfo->te = 0;
355 				NG_CAR_PERFORM_MATCH_ACTION(hinfo->conf.red_action);
356 			}
357 		/* If not green and mode is SINGLE/DOUBLE RATE. */
358 		} else {
359 			/* Check extended token bucket. */
360 			if (hinfo->te - len >= 0) {
361 				/* This packet is yellow */
362 				++hinfo->stats.yellow_pkts;
363 				hinfo->te -= len;
364 				NG_CAR_PERFORM_MATCH_ACTION(hinfo->conf.yellow_action);
365 			} else {
366 				/* This packet is red */
367 				++hinfo->stats.red_pkts;
368 				NG_CAR_PERFORM_MATCH_ACTION(hinfo->conf.red_action);
369 			}
370 		}
371 	}
372 
373 #undef NG_CAR_PERFORM_MATCH_ACTION
374 
375 	NG_FWD_ITEM_HOOK(error, item, dest);
376 	if (error != 0)
377 		++hinfo->stats.errors;
378 	++hinfo->stats.passed_pkts;
379 
380 	return (error);
381 }
382 
383 /*
384  * Receive a control message.
385  */
386 static int
387 ng_car_rcvmsg(node_p node, item_p item, hook_p lasthook)
388 {
389 	const priv_p priv = NG_NODE_PRIVATE(node);
390 	struct ng_mesg *resp = NULL;
391 	int error = 0;
392 	struct ng_mesg *msg;
393 
394 	NGI_GET_MSG(item, msg);
395 	switch (msg->header.typecookie) {
396 	case NGM_CAR_COOKIE:
397 		switch (msg->header.cmd) {
398 		case NGM_CAR_GET_STATS:
399 		case NGM_CAR_GETCLR_STATS:
400 			{
401 				struct ng_car_bulkstats *bstats;
402 
403 				NG_MKRESPONSE(resp, msg,
404 					sizeof(*bstats), M_NOWAIT);
405 				if (resp == NULL) {
406 					error = ENOMEM;
407 					break;
408 				}
409 				bstats = (struct ng_car_bulkstats *)resp->data;
410 
411 				bcopy(&priv->upper.stats, &bstats->downstream,
412 				    sizeof(bstats->downstream));
413 				bcopy(&priv->lower.stats, &bstats->upstream,
414 				    sizeof(bstats->upstream));
415 			}
416 			if (msg->header.cmd == NGM_CAR_GET_STATS)
417 				break;
418 		case NGM_CAR_CLR_STATS:
419 			bzero(&priv->upper.stats,
420 				sizeof(priv->upper.stats));
421 			bzero(&priv->lower.stats,
422 				sizeof(priv->lower.stats));
423 			break;
424 		case NGM_CAR_GET_CONF:
425 			{
426 				struct ng_car_bulkconf *bconf;
427 
428 				NG_MKRESPONSE(resp, msg,
429 					sizeof(*bconf), M_NOWAIT);
430 				if (resp == NULL) {
431 					error = ENOMEM;
432 					break;
433 				}
434 				bconf = (struct ng_car_bulkconf *)resp->data;
435 
436 				bcopy(&priv->upper.conf, &bconf->downstream,
437 				    sizeof(bconf->downstream));
438 				bcopy(&priv->lower.conf, &bconf->upstream,
439 				    sizeof(bconf->upstream));
440 				/* Convert internal 1/(8*128) of pps into pps */
441 				if (bconf->downstream.opt & NG_CAR_COUNT_PACKETS) {
442 				    bconf->downstream.cir /= 1024;
443 				    bconf->downstream.pir /= 1024;
444 				    bconf->downstream.cbs /= 128;
445 				    bconf->downstream.ebs /= 128;
446 				}
447 				if (bconf->upstream.opt & NG_CAR_COUNT_PACKETS) {
448 				    bconf->upstream.cir /= 1024;
449 				    bconf->upstream.pir /= 1024;
450 				    bconf->upstream.cbs /= 128;
451 				    bconf->upstream.ebs /= 128;
452 				}
453 			}
454 			break;
455 		case NGM_CAR_SET_CONF:
456 			{
457 				struct ng_car_bulkconf *const bconf =
458 				(struct ng_car_bulkconf *)msg->data;
459 
460 				/* Check for invalid or illegal config. */
461 				if (msg->header.arglen != sizeof(*bconf)) {
462 					error = EINVAL;
463 					break;
464 				}
465 				/* Convert pps into internal 1/(8*128) of pps */
466 				if (bconf->downstream.opt & NG_CAR_COUNT_PACKETS) {
467 				    bconf->downstream.cir *= 1024;
468 				    bconf->downstream.pir *= 1024;
469 				    bconf->downstream.cbs *= 125;
470 				    bconf->downstream.ebs *= 125;
471 				}
472 				if (bconf->upstream.opt & NG_CAR_COUNT_PACKETS) {
473 				    bconf->upstream.cir *= 1024;
474 				    bconf->upstream.pir *= 1024;
475 				    bconf->upstream.cbs *= 125;
476 				    bconf->upstream.ebs *= 125;
477 				}
478 				if ((bconf->downstream.cir > 1000000000) ||
479 				    (bconf->downstream.pir > 1000000000) ||
480 				    (bconf->upstream.cir > 1000000000) ||
481 				    (bconf->upstream.pir > 1000000000) ||
482 				    (bconf->downstream.cbs == 0 &&
483 					bconf->downstream.ebs == 0) ||
484 				    (bconf->upstream.cbs == 0 &&
485 					bconf->upstream.ebs == 0))
486 				{
487 					error = EINVAL;
488 					break;
489 				}
490 				if ((bconf->upstream.mode == NG_CAR_SHAPE) &&
491 				    (bconf->upstream.cir == 0)) {
492 					error = EINVAL;
493 					break;
494 				}
495 				if ((bconf->downstream.mode == NG_CAR_SHAPE) &&
496 				    (bconf->downstream.cir == 0)) {
497 					error = EINVAL;
498 					break;
499 				}
500 
501 				/* Copy downstream config. */
502 				bcopy(&bconf->downstream, &priv->upper.conf,
503 				    sizeof(priv->upper.conf));
504     				priv->upper.tc = priv->upper.conf.cbs;
505 				if (priv->upper.conf.mode == NG_CAR_RED ||
506 				    priv->upper.conf.mode == NG_CAR_SHAPE) {
507 					priv->upper.te = 0;
508 				} else {
509 					priv->upper.te = priv->upper.conf.ebs;
510 				}
511 
512 				/* Copy upstream config. */
513 				bcopy(&bconf->upstream, &priv->lower.conf,
514 				    sizeof(priv->lower.conf));
515     				priv->lower.tc = priv->lower.conf.cbs;
516 				if (priv->lower.conf.mode == NG_CAR_RED ||
517 				    priv->lower.conf.mode == NG_CAR_SHAPE) {
518 					priv->lower.te = 0;
519 				} else {
520 					priv->lower.te = priv->lower.conf.ebs;
521 				}
522 			}
523 			break;
524 		default:
525 			error = EINVAL;
526 			break;
527 		}
528 		break;
529 	default:
530 		error = EINVAL;
531 		break;
532 	}
533 	NG_RESPOND_MSG(error, node, item, resp);
534 	NG_FREE_MSG(msg);
535 	return (error);
536 }
537 
538 /*
539  * Do local shutdown processing.
540  */
541 static int
542 ng_car_shutdown(node_p node)
543 {
544 	const priv_p priv = NG_NODE_PRIVATE(node);
545 
546 	ng_uncallout(&priv->upper.q_callout, node);
547 	ng_uncallout(&priv->lower.q_callout, node);
548 	mtx_destroy(&priv->upper.q_mtx);
549 	mtx_destroy(&priv->lower.q_mtx);
550 	NG_NODE_UNREF(priv->node);
551 	free(priv, M_NETGRAPH);
552 	return (0);
553 }
554 
555 /*
556  * Hook disconnection.
557  *
558  * For this type, removal of the last link destroys the node.
559  */
560 static int
561 ng_car_disconnect(hook_p hook)
562 {
563 	struct hookinfo *const hinfo = NG_HOOK_PRIVATE(hook);
564 	const node_p node = NG_HOOK_NODE(hook);
565 	const priv_p priv = NG_NODE_PRIVATE(node);
566 
567 	if (hinfo) {
568 		/* Purge queue if not empty. */
569 		while (hinfo->q_first != hinfo->q_last) {
570 			NG_FREE_M(hinfo->q[hinfo->q_first]);
571 			hinfo->q_first++;
572 			if (hinfo->q_first >= NG_CAR_QUEUE_SIZE)
573 		    		hinfo->q_first = 0;
574 		}
575 		/* Remove hook refs. */
576 		if (hinfo->hook == priv->upper.hook)
577 			priv->lower.dest = NULL;
578 		else
579 			priv->upper.dest = NULL;
580 		hinfo->hook = NULL;
581 	}
582 	/* Already shutting down? */
583 	if ((NG_NODE_NUMHOOKS(NG_HOOK_NODE(hook)) == 0)
584 	    && (NG_NODE_IS_VALID(NG_HOOK_NODE(hook))))
585 		ng_rmnode_self(NG_HOOK_NODE(hook));
586 	return (0);
587 }
588 
589 /*
590  * Hook's token buckets refillment.
591  */
592 static void
593 ng_car_refillhook(struct hookinfo *h)
594 {
595 	struct bintime newt, deltat;
596 	unsigned int deltat_us;
597 
598 	/* Get current time. */
599 	getbinuptime(&newt);
600 
601 	/* Get time delta since last refill. */
602 	deltat = newt;
603 	bintime_sub(&deltat, &h->lastRefill);
604 
605 	/* Time must go forward. */
606 	if (deltat.sec < 0) {
607 	    h->lastRefill = newt;
608 	    return;
609 	}
610 
611 	/* But not too far forward. */
612 	if (deltat.sec >= 1000) {
613 	    deltat_us = (1000 << 20);
614 	} else {
615 	    /* convert bintime to the 1/(2^20) of sec */
616 	    deltat_us = (deltat.sec << 20) + (deltat.frac >> 44);
617 	}
618 
619 	if (h->conf.mode == NG_CAR_SINGLE_RATE) {
620 		int64_t	delta;
621 		/* Refill commited token bucket. */
622 		h->tc += (h->conf.cir * deltat_us) >> 23;
623 		delta = h->tc - h->conf.cbs;
624 		if (delta > 0) {
625 			h->tc = h->conf.cbs;
626 
627 			/* Refill exceeded token bucket. */
628 			h->te += delta;
629 			if (h->te > ((int64_t)h->conf.ebs))
630 				h->te = h->conf.ebs;
631 		}
632 
633 	} else if (h->conf.mode == NG_CAR_DOUBLE_RATE) {
634 		/* Refill commited token bucket. */
635 		h->tc += (h->conf.cir * deltat_us) >> 23;
636 		if (h->tc > ((int64_t)h->conf.cbs))
637 			h->tc = h->conf.cbs;
638 
639 		/* Refill peak token bucket. */
640 		h->te += (h->conf.pir * deltat_us) >> 23;
641 		if (h->te > ((int64_t)h->conf.ebs))
642 			h->te = h->conf.ebs;
643 
644 	} else { /* RED or SHAPE mode. */
645 		/* Refill commited token bucket. */
646 		h->tc += (h->conf.cir * deltat_us) >> 23;
647 		if (h->tc > ((int64_t)h->conf.cbs))
648 			h->tc = h->conf.cbs;
649 	}
650 
651 	/* Remember this moment. */
652 	h->lastRefill = newt;
653 }
654 
655 /*
656  * Schedule callout when we will have required tokens.
657  */
658 static void
659 ng_car_schedule(struct hookinfo *hinfo)
660 {
661 	int 	delay;
662 
663 	delay = (-(hinfo->tc)) * hz * 8 / hinfo->conf.cir + 1;
664 
665 	ng_callout(&hinfo->q_callout, NG_HOOK_NODE(hinfo->hook), hinfo->hook,
666 	    delay, &ng_car_q_event, NULL, 0);
667 }
668 
669 /*
670  * Queue processing callout handler.
671  */
672 void
673 ng_car_q_event(node_p node, hook_p hook, void *arg, int arg2)
674 {
675 	struct hookinfo	*hinfo = NG_HOOK_PRIVATE(hook);
676 	item_p 		item;
677 	struct mbuf 	*m;
678 	int		error;
679 
680 	/* Refill tokens for time we have slept. */
681 	ng_car_refillhook(hinfo);
682 
683 	if (hinfo->dest != NULL) {
684 		/* If we have some tokens */
685 		while (hinfo->tc >= 0) {
686 
687 			/* Send packet. */
688 			m = hinfo->q[hinfo->q_first];
689 			if ((item = ng_package_data(m, NG_NOFLAGS)) != NULL)
690 		    		NG_FWD_ITEM_HOOK(error, item, hinfo->dest);
691 
692 			/* Get next one. */
693 			hinfo->q_first++;
694 			if (hinfo->q_first >= NG_CAR_QUEUE_SIZE)
695 				hinfo->q_first = 0;
696 
697 			/* Stop if none left. */
698 			if (hinfo->q_first == hinfo->q_last)
699 				break;
700 
701 			/* If we have more packet, try it. */
702 			m = hinfo->q[hinfo->q_first];
703 			if (hinfo->conf.opt & NG_CAR_COUNT_PACKETS) {
704 				hinfo->tc -= 128;
705 			} else {
706 				hinfo->tc -= m->m_pkthdr.len;
707 			}
708 		}
709 	}
710 
711 	/* If something left */
712 	if (hinfo->q_first != hinfo->q_last)
713 		/* Schedule queue processing. */
714 		ng_car_schedule(hinfo);
715 }
716 
717 /*
718  * Enqueue packet.
719  */
720 static void
721 ng_car_enqueue(struct hookinfo *hinfo, item_p item)
722 {
723 	struct mbuf 	*m;
724 	int		len;
725 
726 	NGI_GET_M(item, m);
727 	NG_FREE_ITEM(item);
728 
729 	/* Lock queue mutex. */
730 	mtx_lock(&hinfo->q_mtx);
731 
732 	/* Calculate used queue length. */
733 	len = hinfo->q_last - hinfo->q_first;
734 	if (len < 0)
735 		len += NG_CAR_QUEUE_SIZE;
736 
737 	/* If queue is overflowed or we have no RED tokens. */
738 	if ((len >= (NG_CAR_QUEUE_SIZE - 1)) ||
739 	    (hinfo->te + len >= NG_CAR_QUEUE_SIZE)) {
740 		/* Drop packet. */
741 		++hinfo->stats.red_pkts;
742 		NG_FREE_M(m);
743 
744 		hinfo->te = 0;
745 	} else {
746 		/* This packet is yellow. */
747 		++hinfo->stats.yellow_pkts;
748 
749 		/* Enqueue packet. */
750 		hinfo->q[hinfo->q_last] = m;
751 		hinfo->q_last++;
752 		if (hinfo->q_last >= NG_CAR_QUEUE_SIZE)
753 			hinfo->q_last = 0;
754 
755 		/* Use RED tokens. */
756 		if (len > NG_CAR_QUEUE_MIN_TH)
757 			hinfo->te += len - NG_CAR_QUEUE_MIN_TH;
758 
759 		/* If this is a first packet in the queue. */
760 		if (len == 0) {
761 			if (hinfo->conf.opt & NG_CAR_COUNT_PACKETS) {
762 				hinfo->tc -= 128;
763 			} else {
764 				hinfo->tc -= m->m_pkthdr.len;
765 			}
766 
767 			/* Schedule queue processing. */
768 			ng_car_schedule(hinfo);
769 		}
770 	}
771 
772 	/* Unlock queue mutex. */
773 	mtx_unlock(&hinfo->q_mtx);
774 }
775