xref: /freebsd/sys/net/altq/altq_rmclass.c (revision e8e8c939350bdf3c228a411caa9660c607c27a11)
1 /*-
2  * Copyright (c) 1991-1997 Regents of the University of California.
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, this list of conditions and the following disclaimer.
10  * 2. Redistributions in binary form must reproduce the above copyright
11  *    notice, this list of conditions and the following disclaimer in the
12  *    documentation and/or other materials provided with the distribution.
13  * 3. All advertising materials mentioning features or use of this software
14  *    must display the following acknowledgement:
15  *      This product includes software developed by the Network Research
16  *      Group at Lawrence Berkeley Laboratory.
17  * 4. Neither the name of the University nor of the Laboratory may be used
18  *    to endorse or promote products derived from this software without
19  *    specific prior written permission.
20  *
21  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31  * SUCH DAMAGE.
32  *
33  * LBL code modified by speer@eng.sun.com, May 1977.
34  * For questions and/or comments, please send mail to cbq@ee.lbl.gov
35  *
36  * @(#)rm_class.c  1.48     97/12/05 SMI
37  * $KAME: altq_rmclass.c,v 1.19 2005/04/13 03:44:25 suz Exp $
38  * $FreeBSD$
39  */
40 #include "opt_altq.h"
41 #include "opt_inet.h"
42 #include "opt_inet6.h"
43 #ifdef ALTQ_CBQ	/* cbq is enabled by ALTQ_CBQ option in opt_altq.h */
44 
45 #include <sys/param.h>
46 #include <sys/malloc.h>
47 #include <sys/mbuf.h>
48 #include <sys/socket.h>
49 #include <sys/systm.h>
50 #include <sys/errno.h>
51 #include <sys/time.h>
52 #ifdef ALTQ3_COMPAT
53 #include <sys/kernel.h>
54 #endif
55 
56 #include <net/if.h>
57 #include <net/if_var.h>
58 #ifdef ALTQ3_COMPAT
59 #include <netinet/in.h>
60 #include <netinet/in_systm.h>
61 #include <netinet/ip.h>
62 #endif
63 
64 #include <net/altq/if_altq.h>
65 #include <net/altq/altq.h>
66 #include <net/altq/altq_rmclass.h>
67 #include <net/altq/altq_rmclass_debug.h>
68 #include <net/altq/altq_red.h>
69 #include <net/altq/altq_rio.h>
70 
71 /*
72  * Local Macros
73  */
74 
75 #define	reset_cutoff(ifd)	{ ifd->cutoff_ = RM_MAXDEPTH; }
76 
77 /*
78  * Local routines.
79  */
80 
81 static int	rmc_satisfied(struct rm_class *, struct timeval *);
82 static void	rmc_wrr_set_weights(struct rm_ifdat *);
83 static void	rmc_depth_compute(struct rm_class *);
84 static void	rmc_depth_recompute(rm_class_t *);
85 
86 static mbuf_t	*_rmc_wrr_dequeue_next(struct rm_ifdat *, int);
87 static mbuf_t	*_rmc_prr_dequeue_next(struct rm_ifdat *, int);
88 
89 static int	_rmc_addq(rm_class_t *, mbuf_t *);
90 static void	_rmc_dropq(rm_class_t *);
91 static mbuf_t	*_rmc_getq(rm_class_t *);
92 static mbuf_t	*_rmc_pollq(rm_class_t *);
93 
94 static int	rmc_under_limit(struct rm_class *, struct timeval *);
95 static void	rmc_tl_satisfied(struct rm_ifdat *, struct timeval *);
96 static void	rmc_drop_action(struct rm_class *);
97 static void	rmc_restart(struct rm_class *);
98 static void	rmc_root_overlimit(struct rm_class *, struct rm_class *);
99 
100 #define	BORROW_OFFTIME
101 /*
102  * BORROW_OFFTIME (experimental):
103  * borrow the offtime of the class borrowing from.
104  * the reason is that when its own offtime is set, the class is unable
105  * to borrow much, especially when cutoff is taking effect.
106  * but when the borrowed class is overloaded (advidle is close to minidle),
107  * use the borrowing class's offtime to avoid overload.
108  */
109 #define	ADJUST_CUTOFF
110 /*
111  * ADJUST_CUTOFF (experimental):
112  * if no underlimit class is found due to cutoff, increase cutoff and
113  * retry the scheduling loop.
114  * also, don't invoke delay_actions while cutoff is taking effect,
115  * since a sleeping class won't have a chance to be scheduled in the
116  * next loop.
117  *
118  * now heuristics for setting the top-level variable (cutoff_) becomes:
119  *	1. if a packet arrives for a not-overlimit class, set cutoff
120  *	   to the depth of the class.
121  *	2. if cutoff is i, and a packet arrives for an overlimit class
122  *	   with an underlimit ancestor at a lower level than i (say j),
123  *	   then set cutoff to j.
124  *	3. at scheduling a packet, if there is no underlimit class
125  *	   due to the current cutoff level, increase cutoff by 1 and
126  *	   then try to schedule again.
127  */
128 
129 /*
130  * rm_class_t *
131  * rmc_newclass(...) - Create a new resource management class at priority
132  * 'pri' on the interface given by 'ifd'.
133  *
134  * nsecPerByte  is the data rate of the interface in nanoseconds/byte.
135  *              E.g., 800 for a 10Mb/s ethernet.  If the class gets less
136  *              than 100% of the bandwidth, this number should be the
137  *              'effective' rate for the class.  Let f be the
138  *              bandwidth fraction allocated to this class, and let
139  *              nsPerByte be the data rate of the output link in
140  *              nanoseconds/byte.  Then nsecPerByte is set to
141  *              nsPerByte / f.  E.g., 1600 (= 800 / .5)
142  *              for a class that gets 50% of an ethernet's bandwidth.
143  *
144  * action       the routine to call when the class is over limit.
145  *
146  * maxq         max allowable queue size for class (in packets).
147  *
148  * parent       parent class pointer.
149  *
150  * borrow       class to borrow from (should be either 'parent' or null).
151  *
152  * maxidle      max value allowed for class 'idle' time estimate (this
153  *              parameter determines how large an initial burst of packets
154  *              can be before overlimit action is invoked.
155  *
156  * offtime      how long 'delay' action will delay when class goes over
157  *              limit (this parameter determines the steady-state burst
158  *              size when a class is running over its limit).
159  *
160  * Maxidle and offtime have to be computed from the following:  If the
161  * average packet size is s, the bandwidth fraction allocated to this
162  * class is f, we want to allow b packet bursts, and the gain of the
163  * averaging filter is g (= 1 - 2^(-RM_FILTER_GAIN)), then:
164  *
165  *   ptime = s * nsPerByte * (1 - f) / f
166  *   maxidle = ptime * (1 - g^b) / g^b
167  *   minidle = -ptime * (1 / (f - 1))
168  *   offtime = ptime * (1 + 1/(1 - g) * (1 - g^(b - 1)) / g^(b - 1)
169  *
170  * Operationally, it's convenient to specify maxidle & offtime in units
171  * independent of the link bandwidth so the maxidle & offtime passed to
172  * this routine are the above values multiplied by 8*f/(1000*nsPerByte).
173  * (The constant factor is a scale factor needed to make the parameters
174  * integers.  This scaling also means that the 'unscaled' values of
175  * maxidle*nsecPerByte/8 and offtime*nsecPerByte/8 will be in microseconds,
176  * not nanoseconds.)  Also note that the 'idle' filter computation keeps
177  * an estimate scaled upward by 2^RM_FILTER_GAIN so the passed value of
178  * maxidle also must be scaled upward by this value.  Thus, the passed
179  * values for maxidle and offtime can be computed as follows:
180  *
181  * maxidle = maxidle * 2^RM_FILTER_GAIN * 8 / (1000 * nsecPerByte)
182  * offtime = offtime * 8 / (1000 * nsecPerByte)
183  *
184  * When USE_HRTIME is employed, then maxidle and offtime become:
185  * 	maxidle = maxilde * (8.0 / nsecPerByte);
186  * 	offtime = offtime * (8.0 / nsecPerByte);
187  */
188 struct rm_class *
189 rmc_newclass(int pri, struct rm_ifdat *ifd, u_int nsecPerByte,
190     void (*action)(rm_class_t *, rm_class_t *), int maxq,
191     struct rm_class *parent, struct rm_class *borrow, u_int maxidle,
192     int minidle, u_int offtime, int pktsize, int flags)
193 {
194 	struct rm_class	*cl;
195 	struct rm_class	*peer;
196 	int		 s;
197 
198 	if (pri >= RM_MAXPRIO)
199 		return (NULL);
200 #ifndef ALTQ_RED
201 	if (flags & RMCF_RED) {
202 #ifdef ALTQ_DEBUG
203 		printf("rmc_newclass: RED not configured for CBQ!\n");
204 #endif
205 		return (NULL);
206 	}
207 #endif
208 #ifndef ALTQ_RIO
209 	if (flags & RMCF_RIO) {
210 #ifdef ALTQ_DEBUG
211 		printf("rmc_newclass: RIO not configured for CBQ!\n");
212 #endif
213 		return (NULL);
214 	}
215 #endif
216 
217 	cl = malloc(sizeof(struct rm_class), M_DEVBUF, M_NOWAIT | M_ZERO);
218 	if (cl == NULL)
219 		return (NULL);
220 	CALLOUT_INIT(&cl->callout_);
221 	cl->q_ = malloc(sizeof(class_queue_t), M_DEVBUF, M_NOWAIT | M_ZERO);
222 	if (cl->q_ == NULL) {
223 		free(cl, M_DEVBUF);
224 		return (NULL);
225 	}
226 
227 	/*
228 	 * Class initialization.
229 	 */
230 	cl->children_ = NULL;
231 	cl->parent_ = parent;
232 	cl->borrow_ = borrow;
233 	cl->leaf_ = 1;
234 	cl->ifdat_ = ifd;
235 	cl->pri_ = pri;
236 	cl->allotment_ = RM_NS_PER_SEC / nsecPerByte; /* Bytes per sec */
237 	cl->depth_ = 0;
238 	cl->qthresh_ = 0;
239 	cl->ns_per_byte_ = nsecPerByte;
240 
241 	qlimit(cl->q_) = maxq;
242 	qtype(cl->q_) = Q_DROPHEAD;
243 	qlen(cl->q_) = 0;
244 	cl->flags_ = flags;
245 
246 #if 1 /* minidle is also scaled in ALTQ */
247 	cl->minidle_ = (minidle * (int)nsecPerByte) / 8;
248 	if (cl->minidle_ > 0)
249 		cl->minidle_ = 0;
250 #else
251 	cl->minidle_ = minidle;
252 #endif
253 	cl->maxidle_ = (maxidle * nsecPerByte) / 8;
254 	if (cl->maxidle_ == 0)
255 		cl->maxidle_ = 1;
256 #if 1 /* offtime is also scaled in ALTQ */
257 	cl->avgidle_ = cl->maxidle_;
258 	cl->offtime_ = ((offtime * nsecPerByte) / 8) >> RM_FILTER_GAIN;
259 	if (cl->offtime_ == 0)
260 		cl->offtime_ = 1;
261 #else
262 	cl->avgidle_ = 0;
263 	cl->offtime_ = (offtime * nsecPerByte) / 8;
264 #endif
265 	cl->overlimit = action;
266 
267 #ifdef ALTQ_RED
268 	if (flags & (RMCF_RED|RMCF_RIO)) {
269 		int red_flags, red_pkttime;
270 
271 		red_flags = 0;
272 		if (flags & RMCF_ECN)
273 			red_flags |= REDF_ECN;
274 		if (flags & RMCF_FLOWVALVE)
275 			red_flags |= REDF_FLOWVALVE;
276 #ifdef ALTQ_RIO
277 		if (flags & RMCF_CLEARDSCP)
278 			red_flags |= RIOF_CLEARDSCP;
279 #endif
280 		red_pkttime = nsecPerByte * pktsize  / 1000;
281 
282 		if (flags & RMCF_RED) {
283 			cl->red_ = red_alloc(0, 0,
284 			    qlimit(cl->q_) * 10/100,
285 			    qlimit(cl->q_) * 30/100,
286 			    red_flags, red_pkttime);
287 			if (cl->red_ != NULL)
288 				qtype(cl->q_) = Q_RED;
289 		}
290 #ifdef ALTQ_RIO
291 		else {
292 			cl->red_ = (red_t *)rio_alloc(0, NULL,
293 						      red_flags, red_pkttime);
294 			if (cl->red_ != NULL)
295 				qtype(cl->q_) = Q_RIO;
296 		}
297 #endif
298 	}
299 #endif /* ALTQ_RED */
300 
301 	/*
302 	 * put the class into the class tree
303 	 */
304 	s = splnet();
305 	IFQ_LOCK(ifd->ifq_);
306 	if ((peer = ifd->active_[pri]) != NULL) {
307 		/* find the last class at this pri */
308 		cl->peer_ = peer;
309 		while (peer->peer_ != ifd->active_[pri])
310 			peer = peer->peer_;
311 		peer->peer_ = cl;
312 	} else {
313 		ifd->active_[pri] = cl;
314 		cl->peer_ = cl;
315 	}
316 
317 	if (cl->parent_) {
318 		cl->next_ = parent->children_;
319 		parent->children_ = cl;
320 		parent->leaf_ = 0;
321 	}
322 
323 	/*
324 	 * Compute the depth of this class and its ancestors in the class
325 	 * hierarchy.
326 	 */
327 	rmc_depth_compute(cl);
328 
329 	/*
330 	 * If CBQ's WRR is enabled, then initialize the class WRR state.
331 	 */
332 	if (ifd->wrr_) {
333 		ifd->num_[pri]++;
334 		ifd->alloc_[pri] += cl->allotment_;
335 		rmc_wrr_set_weights(ifd);
336 	}
337 	IFQ_UNLOCK(ifd->ifq_);
338 	splx(s);
339 	return (cl);
340 }
341 
342 int
343 rmc_modclass(struct rm_class *cl, u_int nsecPerByte, int maxq, u_int maxidle,
344     int minidle, u_int offtime, int pktsize)
345 {
346 	struct rm_ifdat	*ifd;
347 	u_int		 old_allotment;
348 	int		 s;
349 
350 	ifd = cl->ifdat_;
351 	old_allotment = cl->allotment_;
352 
353 	s = splnet();
354 	IFQ_LOCK(ifd->ifq_);
355 	cl->allotment_ = RM_NS_PER_SEC / nsecPerByte; /* Bytes per sec */
356 	cl->qthresh_ = 0;
357 	cl->ns_per_byte_ = nsecPerByte;
358 
359 	qlimit(cl->q_) = maxq;
360 
361 #if 1 /* minidle is also scaled in ALTQ */
362 	cl->minidle_ = (minidle * nsecPerByte) / 8;
363 	if (cl->minidle_ > 0)
364 		cl->minidle_ = 0;
365 #else
366 	cl->minidle_ = minidle;
367 #endif
368 	cl->maxidle_ = (maxidle * nsecPerByte) / 8;
369 	if (cl->maxidle_ == 0)
370 		cl->maxidle_ = 1;
371 #if 1 /* offtime is also scaled in ALTQ */
372 	cl->avgidle_ = cl->maxidle_;
373 	cl->offtime_ = ((offtime * nsecPerByte) / 8) >> RM_FILTER_GAIN;
374 	if (cl->offtime_ == 0)
375 		cl->offtime_ = 1;
376 #else
377 	cl->avgidle_ = 0;
378 	cl->offtime_ = (offtime * nsecPerByte) / 8;
379 #endif
380 
381 	/*
382 	 * If CBQ's WRR is enabled, then initialize the class WRR state.
383 	 */
384 	if (ifd->wrr_) {
385 		ifd->alloc_[cl->pri_] += cl->allotment_ - old_allotment;
386 		rmc_wrr_set_weights(ifd);
387 	}
388 	IFQ_UNLOCK(ifd->ifq_);
389 	splx(s);
390 	return (0);
391 }
392 
393 /*
394  * static void
395  * rmc_wrr_set_weights(struct rm_ifdat *ifdat) - This function computes
396  *	the appropriate run robin weights for the CBQ weighted round robin
397  *	algorithm.
398  *
399  *	Returns: NONE
400  */
401 
402 static void
403 rmc_wrr_set_weights(struct rm_ifdat *ifd)
404 {
405 	int		i;
406 	struct rm_class	*cl, *clh;
407 
408 	for (i = 0; i < RM_MAXPRIO; i++) {
409 		/*
410 		 * This is inverted from that of the simulator to
411 		 * maintain precision.
412 		 */
413 		if (ifd->num_[i] == 0)
414 			ifd->M_[i] = 0;
415 		else
416 			ifd->M_[i] = ifd->alloc_[i] /
417 				(ifd->num_[i] * ifd->maxpkt_);
418 		/*
419 		 * Compute the weighted allotment for each class.
420 		 * This takes the expensive div instruction out
421 		 * of the main loop for the wrr scheduling path.
422 		 * These only get recomputed when a class comes or
423 		 * goes.
424 		 */
425 		if (ifd->active_[i] != NULL) {
426 			clh = cl = ifd->active_[i];
427 			do {
428 				/* safe-guard for slow link or alloc_ == 0 */
429 				if (ifd->M_[i] == 0)
430 					cl->w_allotment_ = 0;
431 				else
432 					cl->w_allotment_ = cl->allotment_ /
433 						ifd->M_[i];
434 				cl = cl->peer_;
435 			} while ((cl != NULL) && (cl != clh));
436 		}
437 	}
438 }
439 
440 int
441 rmc_get_weight(struct rm_ifdat *ifd, int pri)
442 {
443 	if ((pri >= 0) && (pri < RM_MAXPRIO))
444 		return (ifd->M_[pri]);
445 	else
446 		return (0);
447 }
448 
449 /*
450  * static void
451  * rmc_depth_compute(struct rm_class *cl) - This function computes the
452  *	appropriate depth of class 'cl' and its ancestors.
453  *
454  *	Returns:	NONE
455  */
456 
457 static void
458 rmc_depth_compute(struct rm_class *cl)
459 {
460 	rm_class_t	*t = cl, *p;
461 
462 	/*
463 	 * Recompute the depth for the branch of the tree.
464 	 */
465 	while (t != NULL) {
466 		p = t->parent_;
467 		if (p && (t->depth_ >= p->depth_)) {
468 			p->depth_ = t->depth_ + 1;
469 			t = p;
470 		} else
471 			t = NULL;
472 	}
473 }
474 
475 /*
476  * static void
477  * rmc_depth_recompute(struct rm_class *cl) - This function re-computes
478  *	the depth of the tree after a class has been deleted.
479  *
480  *	Returns:	NONE
481  */
482 
483 static void
484 rmc_depth_recompute(rm_class_t *cl)
485 {
486 #if 1 /* ALTQ */
487 	rm_class_t	*p, *t;
488 
489 	p = cl;
490 	while (p != NULL) {
491 		if ((t = p->children_) == NULL) {
492 			p->depth_ = 0;
493 		} else {
494 			int cdepth = 0;
495 
496 			while (t != NULL) {
497 				if (t->depth_ > cdepth)
498 					cdepth = t->depth_;
499 				t = t->next_;
500 			}
501 
502 			if (p->depth_ == cdepth + 1)
503 				/* no change to this parent */
504 				return;
505 
506 			p->depth_ = cdepth + 1;
507 		}
508 
509 		p = p->parent_;
510 	}
511 #else
512 	rm_class_t	*t;
513 
514 	if (cl->depth_ >= 1) {
515 		if (cl->children_ == NULL) {
516 			cl->depth_ = 0;
517 		} else if ((t = cl->children_) != NULL) {
518 			while (t != NULL) {
519 				if (t->children_ != NULL)
520 					rmc_depth_recompute(t);
521 				t = t->next_;
522 			}
523 		} else
524 			rmc_depth_compute(cl);
525 	}
526 #endif
527 }
528 
529 /*
530  * void
531  * rmc_delete_class(struct rm_ifdat *ifdat, struct rm_class *cl) - This
532  *	function deletes a class from the link-sharing structure and frees
533  *	all resources associated with the class.
534  *
535  *	Returns: NONE
536  */
537 
538 void
539 rmc_delete_class(struct rm_ifdat *ifd, struct rm_class *cl)
540 {
541 	struct rm_class	*p, *head, *previous;
542 	int		 s;
543 
544 	ASSERT(cl->children_ == NULL);
545 
546 	if (cl->sleeping_)
547 		CALLOUT_STOP(&cl->callout_);
548 
549 	s = splnet();
550 	IFQ_LOCK(ifd->ifq_);
551 	/*
552 	 * Free packets in the packet queue.
553 	 * XXX - this may not be a desired behavior.  Packets should be
554 	 *		re-queued.
555 	 */
556 	rmc_dropall(cl);
557 
558 	/*
559 	 * If the class has a parent, then remove the class from the
560 	 * class from the parent's children chain.
561 	 */
562 	if (cl->parent_ != NULL) {
563 		head = cl->parent_->children_;
564 		p = previous = head;
565 		if (head->next_ == NULL) {
566 			ASSERT(head == cl);
567 			cl->parent_->children_ = NULL;
568 			cl->parent_->leaf_ = 1;
569 		} else while (p != NULL) {
570 			if (p == cl) {
571 				if (cl == head)
572 					cl->parent_->children_ = cl->next_;
573 				else
574 					previous->next_ = cl->next_;
575 				cl->next_ = NULL;
576 				p = NULL;
577 			} else {
578 				previous = p;
579 				p = p->next_;
580 			}
581 		}
582 	}
583 
584 	/*
585 	 * Delete class from class priority peer list.
586 	 */
587 	if ((p = ifd->active_[cl->pri_]) != NULL) {
588 		/*
589 		 * If there is more than one member of this priority
590 		 * level, then look for class(cl) in the priority level.
591 		 */
592 		if (p != p->peer_) {
593 			while (p->peer_ != cl)
594 				p = p->peer_;
595 			p->peer_ = cl->peer_;
596 
597 			if (ifd->active_[cl->pri_] == cl)
598 				ifd->active_[cl->pri_] = cl->peer_;
599 		} else {
600 			ASSERT(p == cl);
601 			ifd->active_[cl->pri_] = NULL;
602 		}
603 	}
604 
605 	/*
606 	 * Recompute the WRR weights.
607 	 */
608 	if (ifd->wrr_) {
609 		ifd->alloc_[cl->pri_] -= cl->allotment_;
610 		ifd->num_[cl->pri_]--;
611 		rmc_wrr_set_weights(ifd);
612 	}
613 
614 	/*
615 	 * Re-compute the depth of the tree.
616 	 */
617 #if 1 /* ALTQ */
618 	rmc_depth_recompute(cl->parent_);
619 #else
620 	rmc_depth_recompute(ifd->root_);
621 #endif
622 
623 	IFQ_UNLOCK(ifd->ifq_);
624 	splx(s);
625 
626 	/*
627 	 * Free the class structure.
628 	 */
629 	if (cl->red_ != NULL) {
630 #ifdef ALTQ_RIO
631 		if (q_is_rio(cl->q_))
632 			rio_destroy((rio_t *)cl->red_);
633 #endif
634 #ifdef ALTQ_RED
635 		if (q_is_red(cl->q_))
636 			red_destroy(cl->red_);
637 #endif
638 	}
639 	free(cl->q_, M_DEVBUF);
640 	free(cl, M_DEVBUF);
641 }
642 
643 
644 /*
645  * void
646  * rmc_init(...) - Initialize the resource management data structures
647  *	associated with the output portion of interface 'ifp'.  'ifd' is
648  *	where the structures will be built (for backwards compatibility, the
649  *	structures aren't kept in the ifnet struct).  'nsecPerByte'
650  *	gives the link speed (inverse of bandwidth) in nanoseconds/byte.
651  *	'restart' is the driver-specific routine that the generic 'delay
652  *	until under limit' action will call to restart output.  `maxq'
653  *	is the queue size of the 'link' & 'default' classes.  'maxqueued'
654  *	is the maximum number of packets that the resource management
655  *	code will allow to be queued 'downstream' (this is typically 1).
656  *
657  *	Returns:	NONE
658  */
659 
660 void
661 rmc_init(struct ifaltq *ifq, struct rm_ifdat *ifd, u_int nsecPerByte,
662     void (*restart)(struct ifaltq *), int maxq, int maxqueued, u_int maxidle,
663     int minidle, u_int offtime, int flags)
664 {
665 	int		i, mtu;
666 
667 	/*
668 	 * Initialize the CBQ tracing/debug facility.
669 	 */
670 	CBQTRACEINIT();
671 
672 	bzero((char *)ifd, sizeof (*ifd));
673 	mtu = ifq->altq_ifp->if_mtu;
674 	ifd->ifq_ = ifq;
675 	ifd->restart = restart;
676 	ifd->maxqueued_ = maxqueued;
677 	ifd->ns_per_byte_ = nsecPerByte;
678 	ifd->maxpkt_ = mtu;
679 	ifd->wrr_ = (flags & RMCF_WRR) ? 1 : 0;
680 	ifd->efficient_ = (flags & RMCF_EFFICIENT) ? 1 : 0;
681 #if 1
682 	ifd->maxiftime_ = mtu * nsecPerByte / 1000 * 16;
683 	if (mtu * nsecPerByte > 10 * 1000000)
684 		ifd->maxiftime_ /= 4;
685 #endif
686 
687 	reset_cutoff(ifd);
688 	CBQTRACE(rmc_init, 'INIT', ifd->cutoff_);
689 
690 	/*
691 	 * Initialize the CBQ's WRR state.
692 	 */
693 	for (i = 0; i < RM_MAXPRIO; i++) {
694 		ifd->alloc_[i] = 0;
695 		ifd->M_[i] = 0;
696 		ifd->num_[i] = 0;
697 		ifd->na_[i] = 0;
698 		ifd->active_[i] = NULL;
699 	}
700 
701 	/*
702 	 * Initialize current packet state.
703 	 */
704 	ifd->qi_ = 0;
705 	ifd->qo_ = 0;
706 	for (i = 0; i < RM_MAXQUEUED; i++) {
707 		ifd->class_[i] = NULL;
708 		ifd->curlen_[i] = 0;
709 		ifd->borrowed_[i] = NULL;
710 	}
711 
712 	/*
713 	 * Create the root class of the link-sharing structure.
714 	 */
715 	if ((ifd->root_ = rmc_newclass(0, ifd,
716 				       nsecPerByte,
717 				       rmc_root_overlimit, maxq, 0, 0,
718 				       maxidle, minidle, offtime,
719 				       0, 0)) == NULL) {
720 		printf("rmc_init: root class not allocated\n");
721 		return ;
722 	}
723 	ifd->root_->depth_ = 0;
724 }
725 
726 /*
727  * void
728  * rmc_queue_packet(struct rm_class *cl, mbuf_t *m) - Add packet given by
729  *	mbuf 'm' to queue for resource class 'cl'.  This routine is called
730  *	by a driver's if_output routine.  This routine must be called with
731  *	output packet completion interrupts locked out (to avoid racing with
732  *	rmc_dequeue_next).
733  *
734  *	Returns:	0 on successful queueing
735  *			-1 when packet drop occurs
736  */
737 int
738 rmc_queue_packet(struct rm_class *cl, mbuf_t *m)
739 {
740 	struct timeval	 now;
741 	struct rm_ifdat *ifd = cl->ifdat_;
742 	int		 cpri = cl->pri_;
743 	int		 is_empty = qempty(cl->q_);
744 
745 	RM_GETTIME(now);
746 	if (ifd->cutoff_ > 0) {
747 		if (TV_LT(&cl->undertime_, &now)) {
748 			if (ifd->cutoff_ > cl->depth_)
749 				ifd->cutoff_ = cl->depth_;
750 			CBQTRACE(rmc_queue_packet, 'ffoc', cl->depth_);
751 		}
752 #if 1 /* ALTQ */
753 		else {
754 			/*
755 			 * the class is overlimit. if the class has
756 			 * underlimit ancestors, set cutoff to the lowest
757 			 * depth among them.
758 			 */
759 			struct rm_class *borrow = cl->borrow_;
760 
761 			while (borrow != NULL &&
762 			       borrow->depth_ < ifd->cutoff_) {
763 				if (TV_LT(&borrow->undertime_, &now)) {
764 					ifd->cutoff_ = borrow->depth_;
765 					CBQTRACE(rmc_queue_packet, 'ffob', ifd->cutoff_);
766 					break;
767 				}
768 				borrow = borrow->borrow_;
769 			}
770 		}
771 #else /* !ALTQ */
772 		else if ((ifd->cutoff_ > 1) && cl->borrow_) {
773 			if (TV_LT(&cl->borrow_->undertime_, &now)) {
774 				ifd->cutoff_ = cl->borrow_->depth_;
775 				CBQTRACE(rmc_queue_packet, 'ffob',
776 					 cl->borrow_->depth_);
777 			}
778 		}
779 #endif /* !ALTQ */
780 	}
781 
782 	if (_rmc_addq(cl, m) < 0)
783 		/* failed */
784 		return (-1);
785 
786 	if (is_empty) {
787 		CBQTRACE(rmc_queue_packet, 'ytpe', cl->stats_.handle);
788 		ifd->na_[cpri]++;
789 	}
790 
791 	if (qlen(cl->q_) > qlimit(cl->q_)) {
792 		/* note: qlimit can be set to 0 or 1 */
793 		rmc_drop_action(cl);
794 		return (-1);
795 	}
796 	return (0);
797 }
798 
799 /*
800  * void
801  * rmc_tl_satisfied(struct rm_ifdat *ifd, struct timeval *now) - Check all
802  *	classes to see if there are satified.
803  */
804 
805 static void
806 rmc_tl_satisfied(struct rm_ifdat *ifd, struct timeval *now)
807 {
808 	int		 i;
809 	rm_class_t	*p, *bp;
810 
811 	for (i = RM_MAXPRIO - 1; i >= 0; i--) {
812 		if ((bp = ifd->active_[i]) != NULL) {
813 			p = bp;
814 			do {
815 				if (!rmc_satisfied(p, now)) {
816 					ifd->cutoff_ = p->depth_;
817 					return;
818 				}
819 				p = p->peer_;
820 			} while (p != bp);
821 		}
822 	}
823 
824 	reset_cutoff(ifd);
825 }
826 
827 /*
828  * rmc_satisfied - Return 1 of the class is satisfied.  O, otherwise.
829  */
830 
831 static int
832 rmc_satisfied(struct rm_class *cl, struct timeval *now)
833 {
834 	rm_class_t	*p;
835 
836 	if (cl == NULL)
837 		return (1);
838 	if (TV_LT(now, &cl->undertime_))
839 		return (1);
840 	if (cl->depth_ == 0) {
841 		if (!cl->sleeping_ && (qlen(cl->q_) > cl->qthresh_))
842 			return (0);
843 		else
844 			return (1);
845 	}
846 	if (cl->children_ != NULL) {
847 		p = cl->children_;
848 		while (p != NULL) {
849 			if (!rmc_satisfied(p, now))
850 				return (0);
851 			p = p->next_;
852 		}
853 	}
854 
855 	return (1);
856 }
857 
858 /*
859  * Return 1 if class 'cl' is under limit or can borrow from a parent,
860  * 0 if overlimit.  As a side-effect, this routine will invoke the
861  * class overlimit action if the class if overlimit.
862  */
863 
864 static int
865 rmc_under_limit(struct rm_class *cl, struct timeval *now)
866 {
867 	rm_class_t	*p = cl;
868 	rm_class_t	*top;
869 	struct rm_ifdat	*ifd = cl->ifdat_;
870 
871 	ifd->borrowed_[ifd->qi_] = NULL;
872 	/*
873 	 * If cl is the root class, then always return that it is
874 	 * underlimit.  Otherwise, check to see if the class is underlimit.
875 	 */
876 	if (cl->parent_ == NULL)
877 		return (1);
878 
879 	if (cl->sleeping_) {
880 		if (TV_LT(now, &cl->undertime_))
881 			return (0);
882 
883 		CALLOUT_STOP(&cl->callout_);
884 		cl->sleeping_ = 0;
885 		cl->undertime_.tv_sec = 0;
886 		return (1);
887 	}
888 
889 	top = NULL;
890 	while (cl->undertime_.tv_sec && TV_LT(now, &cl->undertime_)) {
891 		if (((cl = cl->borrow_) == NULL) ||
892 		    (cl->depth_ > ifd->cutoff_)) {
893 #ifdef ADJUST_CUTOFF
894 			if (cl != NULL)
895 				/* cutoff is taking effect, just
896 				   return false without calling
897 				   the delay action. */
898 				return (0);
899 #endif
900 #ifdef BORROW_OFFTIME
901 			/*
902 			 * check if the class can borrow offtime too.
903 			 * borrow offtime from the top of the borrow
904 			 * chain if the top class is not overloaded.
905 			 */
906 			if (cl != NULL) {
907 				/* cutoff is taking effect, use this class as top. */
908 				top = cl;
909 				CBQTRACE(rmc_under_limit, 'ffou', ifd->cutoff_);
910 			}
911 			if (top != NULL && top->avgidle_ == top->minidle_)
912 				top = NULL;
913 			p->overtime_ = *now;
914 			(p->overlimit)(p, top);
915 #else
916 			p->overtime_ = *now;
917 			(p->overlimit)(p, NULL);
918 #endif
919 			return (0);
920 		}
921 		top = cl;
922 	}
923 
924 	if (cl != p)
925 		ifd->borrowed_[ifd->qi_] = cl;
926 	return (1);
927 }
928 
929 /*
930  * _rmc_wrr_dequeue_next() - This is scheduler for WRR as opposed to
931  *	Packet-by-packet round robin.
932  *
933  * The heart of the weighted round-robin scheduler, which decides which
934  * class next gets to send a packet.  Highest priority first, then
935  * weighted round-robin within priorites.
936  *
937  * Each able-to-send class gets to send until its byte allocation is
938  * exhausted.  Thus, the active pointer is only changed after a class has
939  * exhausted its allocation.
940  *
941  * If the scheduler finds no class that is underlimit or able to borrow,
942  * then the first class found that had a nonzero queue and is allowed to
943  * borrow gets to send.
944  */
945 
946 static mbuf_t *
947 _rmc_wrr_dequeue_next(struct rm_ifdat *ifd, int op)
948 {
949 	struct rm_class	*cl = NULL, *first = NULL;
950 	u_int		 deficit;
951 	int		 cpri;
952 	mbuf_t		*m;
953 	struct timeval	 now;
954 
955 	RM_GETTIME(now);
956 
957 	/*
958 	 * if the driver polls the top of the queue and then removes
959 	 * the polled packet, we must return the same packet.
960 	 */
961 	if (op == ALTDQ_REMOVE && ifd->pollcache_) {
962 		cl = ifd->pollcache_;
963 		cpri = cl->pri_;
964 		if (ifd->efficient_) {
965 			/* check if this class is overlimit */
966 			if (cl->undertime_.tv_sec != 0 &&
967 			    rmc_under_limit(cl, &now) == 0)
968 				first = cl;
969 		}
970 		ifd->pollcache_ = NULL;
971 		goto _wrr_out;
972 	}
973 	else {
974 		/* mode == ALTDQ_POLL || pollcache == NULL */
975 		ifd->pollcache_ = NULL;
976 		ifd->borrowed_[ifd->qi_] = NULL;
977 	}
978 #ifdef ADJUST_CUTOFF
979  _again:
980 #endif
981 	for (cpri = RM_MAXPRIO - 1; cpri >= 0; cpri--) {
982 		if (ifd->na_[cpri] == 0)
983 			continue;
984 		deficit = 0;
985 		/*
986 		 * Loop through twice for a priority level, if some class
987 		 * was unable to send a packet the first round because
988 		 * of the weighted round-robin mechanism.
989 		 * During the second loop at this level, deficit==2.
990 		 * (This second loop is not needed if for every class,
991 		 * "M[cl->pri_])" times "cl->allotment" is greater than
992 		 * the byte size for the largest packet in the class.)
993 		 */
994  _wrr_loop:
995 		cl = ifd->active_[cpri];
996 		ASSERT(cl != NULL);
997 		do {
998 			if ((deficit < 2) && (cl->bytes_alloc_ <= 0))
999 				cl->bytes_alloc_ += cl->w_allotment_;
1000 			if (!qempty(cl->q_)) {
1001 				if ((cl->undertime_.tv_sec == 0) ||
1002 				    rmc_under_limit(cl, &now)) {
1003 					if (cl->bytes_alloc_ > 0 || deficit > 1)
1004 						goto _wrr_out;
1005 
1006 					/* underlimit but no alloc */
1007 					deficit = 1;
1008 #if 1
1009 					ifd->borrowed_[ifd->qi_] = NULL;
1010 #endif
1011 				}
1012 				else if (first == NULL && cl->borrow_ != NULL)
1013 					first = cl; /* borrowing candidate */
1014 			}
1015 
1016 			cl->bytes_alloc_ = 0;
1017 			cl = cl->peer_;
1018 		} while (cl != ifd->active_[cpri]);
1019 
1020 		if (deficit == 1) {
1021 			/* first loop found an underlimit class with deficit */
1022 			/* Loop on same priority level, with new deficit.  */
1023 			deficit = 2;
1024 			goto _wrr_loop;
1025 		}
1026 	}
1027 
1028 #ifdef ADJUST_CUTOFF
1029 	/*
1030 	 * no underlimit class found.  if cutoff is taking effect,
1031 	 * increase cutoff and try again.
1032 	 */
1033 	if (first != NULL && ifd->cutoff_ < ifd->root_->depth_) {
1034 		ifd->cutoff_++;
1035 		CBQTRACE(_rmc_wrr_dequeue_next, 'ojda', ifd->cutoff_);
1036 		goto _again;
1037 	}
1038 #endif /* ADJUST_CUTOFF */
1039 	/*
1040 	 * If LINK_EFFICIENCY is turned on, then the first overlimit
1041 	 * class we encounter will send a packet if all the classes
1042 	 * of the link-sharing structure are overlimit.
1043 	 */
1044 	reset_cutoff(ifd);
1045 	CBQTRACE(_rmc_wrr_dequeue_next, 'otsr', ifd->cutoff_);
1046 
1047 	if (!ifd->efficient_ || first == NULL)
1048 		return (NULL);
1049 
1050 	cl = first;
1051 	cpri = cl->pri_;
1052 #if 0	/* too time-consuming for nothing */
1053 	if (cl->sleeping_)
1054 		CALLOUT_STOP(&cl->callout_);
1055 	cl->sleeping_ = 0;
1056 	cl->undertime_.tv_sec = 0;
1057 #endif
1058 	ifd->borrowed_[ifd->qi_] = cl->borrow_;
1059 	ifd->cutoff_ = cl->borrow_->depth_;
1060 
1061 	/*
1062 	 * Deque the packet and do the book keeping...
1063 	 */
1064  _wrr_out:
1065 	if (op == ALTDQ_REMOVE) {
1066 		m = _rmc_getq(cl);
1067 		if (m == NULL)
1068 			panic("_rmc_wrr_dequeue_next");
1069 		if (qempty(cl->q_))
1070 			ifd->na_[cpri]--;
1071 
1072 		/*
1073 		 * Update class statistics and link data.
1074 		 */
1075 		if (cl->bytes_alloc_ > 0)
1076 			cl->bytes_alloc_ -= m_pktlen(m);
1077 
1078 		if ((cl->bytes_alloc_ <= 0) || first == cl)
1079 			ifd->active_[cl->pri_] = cl->peer_;
1080 		else
1081 			ifd->active_[cl->pri_] = cl;
1082 
1083 		ifd->class_[ifd->qi_] = cl;
1084 		ifd->curlen_[ifd->qi_] = m_pktlen(m);
1085 		ifd->now_[ifd->qi_] = now;
1086 		ifd->qi_ = (ifd->qi_ + 1) % ifd->maxqueued_;
1087 		ifd->queued_++;
1088 	} else {
1089 		/* mode == ALTDQ_PPOLL */
1090 		m = _rmc_pollq(cl);
1091 		ifd->pollcache_ = cl;
1092 	}
1093 	return (m);
1094 }
1095 
1096 /*
1097  * Dequeue & return next packet from the highest priority class that
1098  * has a packet to send & has enough allocation to send it.  This
1099  * routine is called by a driver whenever it needs a new packet to
1100  * output.
1101  */
1102 static mbuf_t *
1103 _rmc_prr_dequeue_next(struct rm_ifdat *ifd, int op)
1104 {
1105 	mbuf_t		*m;
1106 	int		 cpri;
1107 	struct rm_class	*cl, *first = NULL;
1108 	struct timeval	 now;
1109 
1110 	RM_GETTIME(now);
1111 
1112 	/*
1113 	 * if the driver polls the top of the queue and then removes
1114 	 * the polled packet, we must return the same packet.
1115 	 */
1116 	if (op == ALTDQ_REMOVE && ifd->pollcache_) {
1117 		cl = ifd->pollcache_;
1118 		cpri = cl->pri_;
1119 		ifd->pollcache_ = NULL;
1120 		goto _prr_out;
1121 	} else {
1122 		/* mode == ALTDQ_POLL || pollcache == NULL */
1123 		ifd->pollcache_ = NULL;
1124 		ifd->borrowed_[ifd->qi_] = NULL;
1125 	}
1126 #ifdef ADJUST_CUTOFF
1127  _again:
1128 #endif
1129 	for (cpri = RM_MAXPRIO - 1; cpri >= 0; cpri--) {
1130 		if (ifd->na_[cpri] == 0)
1131 			continue;
1132 		cl = ifd->active_[cpri];
1133 		ASSERT(cl != NULL);
1134 		do {
1135 			if (!qempty(cl->q_)) {
1136 				if ((cl->undertime_.tv_sec == 0) ||
1137 				    rmc_under_limit(cl, &now))
1138 					goto _prr_out;
1139 				if (first == NULL && cl->borrow_ != NULL)
1140 					first = cl;
1141 			}
1142 			cl = cl->peer_;
1143 		} while (cl != ifd->active_[cpri]);
1144 	}
1145 
1146 #ifdef ADJUST_CUTOFF
1147 	/*
1148 	 * no underlimit class found.  if cutoff is taking effect, increase
1149 	 * cutoff and try again.
1150 	 */
1151 	if (first != NULL && ifd->cutoff_ < ifd->root_->depth_) {
1152 		ifd->cutoff_++;
1153 		goto _again;
1154 	}
1155 #endif /* ADJUST_CUTOFF */
1156 	/*
1157 	 * If LINK_EFFICIENCY is turned on, then the first overlimit
1158 	 * class we encounter will send a packet if all the classes
1159 	 * of the link-sharing structure are overlimit.
1160 	 */
1161 	reset_cutoff(ifd);
1162 	if (!ifd->efficient_ || first == NULL)
1163 		return (NULL);
1164 
1165 	cl = first;
1166 	cpri = cl->pri_;
1167 #if 0	/* too time-consuming for nothing */
1168 	if (cl->sleeping_)
1169 		CALLOUT_STOP(&cl->callout_);
1170 	cl->sleeping_ = 0;
1171 	cl->undertime_.tv_sec = 0;
1172 #endif
1173 	ifd->borrowed_[ifd->qi_] = cl->borrow_;
1174 	ifd->cutoff_ = cl->borrow_->depth_;
1175 
1176 	/*
1177 	 * Deque the packet and do the book keeping...
1178 	 */
1179  _prr_out:
1180 	if (op == ALTDQ_REMOVE) {
1181 		m = _rmc_getq(cl);
1182 		if (m == NULL)
1183 			panic("_rmc_prr_dequeue_next");
1184 		if (qempty(cl->q_))
1185 			ifd->na_[cpri]--;
1186 
1187 		ifd->active_[cpri] = cl->peer_;
1188 
1189 		ifd->class_[ifd->qi_] = cl;
1190 		ifd->curlen_[ifd->qi_] = m_pktlen(m);
1191 		ifd->now_[ifd->qi_] = now;
1192 		ifd->qi_ = (ifd->qi_ + 1) % ifd->maxqueued_;
1193 		ifd->queued_++;
1194 	} else {
1195 		/* mode == ALTDQ_POLL */
1196 		m = _rmc_pollq(cl);
1197 		ifd->pollcache_ = cl;
1198 	}
1199 	return (m);
1200 }
1201 
1202 /*
1203  * mbuf_t *
1204  * rmc_dequeue_next(struct rm_ifdat *ifd, struct timeval *now) - this function
1205  *	is invoked by the packet driver to get the next packet to be
1206  *	dequeued and output on the link.  If WRR is enabled, then the
1207  *	WRR dequeue next routine will determine the next packet to sent.
1208  *	Otherwise, packet-by-packet round robin is invoked.
1209  *
1210  *	Returns:	NULL, if a packet is not available or if all
1211  *			classes are overlimit.
1212  *
1213  *			Otherwise, Pointer to the next packet.
1214  */
1215 
1216 mbuf_t *
1217 rmc_dequeue_next(struct rm_ifdat *ifd, int mode)
1218 {
1219 	if (ifd->queued_ >= ifd->maxqueued_)
1220 		return (NULL);
1221 	else if (ifd->wrr_)
1222 		return (_rmc_wrr_dequeue_next(ifd, mode));
1223 	else
1224 		return (_rmc_prr_dequeue_next(ifd, mode));
1225 }
1226 
1227 /*
1228  * Update the utilization estimate for the packet that just completed.
1229  * The packet's class & the parent(s) of that class all get their
1230  * estimators updated.  This routine is called by the driver's output-
1231  * packet-completion interrupt service routine.
1232  */
1233 
1234 /*
1235  * a macro to approximate "divide by 1000" that gives 0.000999,
1236  * if a value has enough effective digits.
1237  * (on pentium, mul takes 9 cycles but div takes 46!)
1238  */
1239 #define	NSEC_TO_USEC(t)	(((t) >> 10) + ((t) >> 16) + ((t) >> 17))
1240 void
1241 rmc_update_class_util(struct rm_ifdat *ifd)
1242 {
1243 	int		 idle, avgidle, pktlen;
1244 	int		 pkt_time, tidle;
1245 	rm_class_t	*cl, *borrowed;
1246 	rm_class_t	*borrows;
1247 	struct timeval	*nowp;
1248 
1249 	/*
1250 	 * Get the most recent completed class.
1251 	 */
1252 	if ((cl = ifd->class_[ifd->qo_]) == NULL)
1253 		return;
1254 
1255 	pktlen = ifd->curlen_[ifd->qo_];
1256 	borrowed = ifd->borrowed_[ifd->qo_];
1257 	borrows = borrowed;
1258 
1259 	PKTCNTR_ADD(&cl->stats_.xmit_cnt, pktlen);
1260 
1261 	/*
1262 	 * Run estimator on class and its ancestors.
1263 	 */
1264 	/*
1265 	 * rm_update_class_util is designed to be called when the
1266 	 * transfer is completed from a xmit complete interrupt,
1267 	 * but most drivers don't implement an upcall for that.
1268 	 * so, just use estimated completion time.
1269 	 * as a result, ifd->qi_ and ifd->qo_ are always synced.
1270 	 */
1271 	nowp = &ifd->now_[ifd->qo_];
1272 	/* get pkt_time (for link) in usec */
1273 #if 1  /* use approximation */
1274 	pkt_time = ifd->curlen_[ifd->qo_] * ifd->ns_per_byte_;
1275 	pkt_time = NSEC_TO_USEC(pkt_time);
1276 #else
1277 	pkt_time = ifd->curlen_[ifd->qo_] * ifd->ns_per_byte_ / 1000;
1278 #endif
1279 #if 1 /* ALTQ4PPP */
1280 	if (TV_LT(nowp, &ifd->ifnow_)) {
1281 		int iftime;
1282 
1283 		/*
1284 		 * make sure the estimated completion time does not go
1285 		 * too far.  it can happen when the link layer supports
1286 		 * data compression or the interface speed is set to
1287 		 * a much lower value.
1288 		 */
1289 		TV_DELTA(&ifd->ifnow_, nowp, iftime);
1290 		if (iftime+pkt_time < ifd->maxiftime_) {
1291 			TV_ADD_DELTA(&ifd->ifnow_, pkt_time, &ifd->ifnow_);
1292 		} else {
1293 			TV_ADD_DELTA(nowp, ifd->maxiftime_, &ifd->ifnow_);
1294 		}
1295 	} else {
1296 		TV_ADD_DELTA(nowp, pkt_time, &ifd->ifnow_);
1297 	}
1298 #else
1299 	if (TV_LT(nowp, &ifd->ifnow_)) {
1300 		TV_ADD_DELTA(&ifd->ifnow_, pkt_time, &ifd->ifnow_);
1301 	} else {
1302 		TV_ADD_DELTA(nowp, pkt_time, &ifd->ifnow_);
1303 	}
1304 #endif
1305 
1306 	while (cl != NULL) {
1307 		TV_DELTA(&ifd->ifnow_, &cl->last_, idle);
1308 		if (idle >= 2000000)
1309 			/*
1310 			 * this class is idle enough, reset avgidle.
1311 			 * (TV_DELTA returns 2000000 us when delta is large.)
1312 			 */
1313 			cl->avgidle_ = cl->maxidle_;
1314 
1315 		/* get pkt_time (for class) in usec */
1316 #if 1  /* use approximation */
1317 		pkt_time = pktlen * cl->ns_per_byte_;
1318 		pkt_time = NSEC_TO_USEC(pkt_time);
1319 #else
1320 		pkt_time = pktlen * cl->ns_per_byte_ / 1000;
1321 #endif
1322 		idle -= pkt_time;
1323 
1324 		avgidle = cl->avgidle_;
1325 		avgidle += idle - (avgidle >> RM_FILTER_GAIN);
1326 		cl->avgidle_ = avgidle;
1327 
1328 		/* Are we overlimit ? */
1329 		if (avgidle <= 0) {
1330 			CBQTRACE(rmc_update_class_util, 'milo', cl->stats_.handle);
1331 #if 1 /* ALTQ */
1332 			/*
1333 			 * need some lower bound for avgidle, otherwise
1334 			 * a borrowing class gets unbounded penalty.
1335 			 */
1336 			if (avgidle < cl->minidle_)
1337 				avgidle = cl->avgidle_ = cl->minidle_;
1338 #endif
1339 			/* set next idle to make avgidle 0 */
1340 			tidle = pkt_time +
1341 				(((1 - RM_POWER) * avgidle) >> RM_FILTER_GAIN);
1342 			TV_ADD_DELTA(nowp, tidle, &cl->undertime_);
1343 			++cl->stats_.over;
1344 		} else {
1345 			cl->avgidle_ =
1346 			    (avgidle > cl->maxidle_) ? cl->maxidle_ : avgidle;
1347 			cl->undertime_.tv_sec = 0;
1348 			if (cl->sleeping_) {
1349 				CALLOUT_STOP(&cl->callout_);
1350 				cl->sleeping_ = 0;
1351 			}
1352 		}
1353 
1354 		if (borrows != NULL) {
1355 			if (borrows != cl)
1356 				++cl->stats_.borrows;
1357 			else
1358 				borrows = NULL;
1359 		}
1360 		cl->last_ = ifd->ifnow_;
1361 		cl->last_pkttime_ = pkt_time;
1362 
1363 #if 1
1364 		if (cl->parent_ == NULL) {
1365 			/* take stats of root class */
1366 			PKTCNTR_ADD(&cl->stats_.xmit_cnt, pktlen);
1367 		}
1368 #endif
1369 
1370 		cl = cl->parent_;
1371 	}
1372 
1373 	/*
1374 	 * Check to see if cutoff needs to set to a new level.
1375 	 */
1376 	cl = ifd->class_[ifd->qo_];
1377 	if (borrowed && (ifd->cutoff_ >= borrowed->depth_)) {
1378 #if 1 /* ALTQ */
1379 		if ((qlen(cl->q_) <= 0) || TV_LT(nowp, &borrowed->undertime_)) {
1380 			rmc_tl_satisfied(ifd, nowp);
1381 			CBQTRACE(rmc_update_class_util, 'broe', ifd->cutoff_);
1382 		} else {
1383 			ifd->cutoff_ = borrowed->depth_;
1384 			CBQTRACE(rmc_update_class_util, 'ffob', borrowed->depth_);
1385 		}
1386 #else /* !ALTQ */
1387 		if ((qlen(cl->q_) <= 1) || TV_LT(&now, &borrowed->undertime_)) {
1388 			reset_cutoff(ifd);
1389 #ifdef notdef
1390 			rmc_tl_satisfied(ifd, &now);
1391 #endif
1392 			CBQTRACE(rmc_update_class_util, 'broe', ifd->cutoff_);
1393 		} else {
1394 			ifd->cutoff_ = borrowed->depth_;
1395 			CBQTRACE(rmc_update_class_util, 'ffob', borrowed->depth_);
1396 		}
1397 #endif /* !ALTQ */
1398 	}
1399 
1400 	/*
1401 	 * Release class slot
1402 	 */
1403 	ifd->borrowed_[ifd->qo_] = NULL;
1404 	ifd->class_[ifd->qo_] = NULL;
1405 	ifd->qo_ = (ifd->qo_ + 1) % ifd->maxqueued_;
1406 	ifd->queued_--;
1407 }
1408 
1409 /*
1410  * void
1411  * rmc_drop_action(struct rm_class *cl) - Generic (not protocol-specific)
1412  *	over-limit action routines.  These get invoked by rmc_under_limit()
1413  *	if a class with packets to send if over its bandwidth limit & can't
1414  *	borrow from a parent class.
1415  *
1416  *	Returns: NONE
1417  */
1418 
1419 static void
1420 rmc_drop_action(struct rm_class *cl)
1421 {
1422 	struct rm_ifdat	*ifd = cl->ifdat_;
1423 
1424 	ASSERT(qlen(cl->q_) > 0);
1425 	_rmc_dropq(cl);
1426 	if (qempty(cl->q_))
1427 		ifd->na_[cl->pri_]--;
1428 }
1429 
1430 void rmc_dropall(struct rm_class *cl)
1431 {
1432 	struct rm_ifdat	*ifd = cl->ifdat_;
1433 
1434 	if (!qempty(cl->q_)) {
1435 		_flushq(cl->q_);
1436 
1437 		ifd->na_[cl->pri_]--;
1438 	}
1439 }
1440 
1441 #if (__FreeBSD_version > 300000)
1442 /* hzto() is removed from FreeBSD-3.0 */
1443 static int hzto(struct timeval *);
1444 
1445 static int
1446 hzto(tv)
1447 	struct timeval *tv;
1448 {
1449 	struct timeval t2;
1450 
1451 	getmicrotime(&t2);
1452 	t2.tv_sec = tv->tv_sec - t2.tv_sec;
1453 	t2.tv_usec = tv->tv_usec - t2.tv_usec;
1454 	return (tvtohz(&t2));
1455 }
1456 #endif /* __FreeBSD_version > 300000 */
1457 
1458 /*
1459  * void
1460  * rmc_delay_action(struct rm_class *cl) - This function is the generic CBQ
1461  *	delay action routine.  It is invoked via rmc_under_limit when the
1462  *	packet is discoverd to be overlimit.
1463  *
1464  *	If the delay action is result of borrow class being overlimit, then
1465  *	delay for the offtime of the borrowing class that is overlimit.
1466  *
1467  *	Returns: NONE
1468  */
1469 
1470 void
1471 rmc_delay_action(struct rm_class *cl, struct rm_class *borrow)
1472 {
1473 	int	delay, t, extradelay;
1474 
1475 	cl->stats_.overactions++;
1476 	TV_DELTA(&cl->undertime_, &cl->overtime_, delay);
1477 #ifndef BORROW_OFFTIME
1478 	delay += cl->offtime_;
1479 #endif
1480 
1481 	if (!cl->sleeping_) {
1482 		CBQTRACE(rmc_delay_action, 'yled', cl->stats_.handle);
1483 #ifdef BORROW_OFFTIME
1484 		if (borrow != NULL)
1485 			extradelay = borrow->offtime_;
1486 		else
1487 #endif
1488 			extradelay = cl->offtime_;
1489 
1490 #ifdef ALTQ
1491 		/*
1492 		 * XXX recalculate suspend time:
1493 		 * current undertime is (tidle + pkt_time) calculated
1494 		 * from the last transmission.
1495 		 *	tidle: time required to bring avgidle back to 0
1496 		 *	pkt_time: target waiting time for this class
1497 		 * we need to replace pkt_time by offtime
1498 		 */
1499 		extradelay -= cl->last_pkttime_;
1500 #endif
1501 		if (extradelay > 0) {
1502 			TV_ADD_DELTA(&cl->undertime_, extradelay, &cl->undertime_);
1503 			delay += extradelay;
1504 		}
1505 
1506 		cl->sleeping_ = 1;
1507 		cl->stats_.delays++;
1508 
1509 		/*
1510 		 * Since packets are phased randomly with respect to the
1511 		 * clock, 1 tick (the next clock tick) can be an arbitrarily
1512 		 * short time so we have to wait for at least two ticks.
1513 		 * NOTE:  If there's no other traffic, we need the timer as
1514 		 * a 'backstop' to restart this class.
1515 		 */
1516 		if (delay > tick * 2) {
1517 			/* FreeBSD rounds up the tick */
1518 			t = hzto(&cl->undertime_);
1519 		} else
1520 			t = 2;
1521 		CALLOUT_RESET(&cl->callout_, t,
1522 			      (timeout_t *)rmc_restart, (caddr_t)cl);
1523 	}
1524 }
1525 
1526 /*
1527  * void
1528  * rmc_restart() - is just a helper routine for rmc_delay_action -- it is
1529  *	called by the system timer code & is responsible checking if the
1530  *	class is still sleeping (it might have been restarted as a side
1531  *	effect of the queue scan on a packet arrival) and, if so, restarting
1532  *	output for the class.  Inspecting the class state & restarting output
1533  *	require locking the class structure.  In general the driver is
1534  *	responsible for locking but this is the only routine that is not
1535  *	called directly or indirectly from the interface driver so it has
1536  *	know about system locking conventions.  Under bsd, locking is done
1537  *	by raising IPL to splimp so that's what's implemented here.  On a
1538  *	different system this would probably need to be changed.
1539  *
1540  *	Returns:	NONE
1541  */
1542 
1543 static void
1544 rmc_restart(struct rm_class *cl)
1545 {
1546 	struct rm_ifdat	*ifd = cl->ifdat_;
1547 	int		 s;
1548 
1549 	s = splnet();
1550 	IFQ_LOCK(ifd->ifq_);
1551 	if (cl->sleeping_) {
1552 		cl->sleeping_ = 0;
1553 		cl->undertime_.tv_sec = 0;
1554 
1555 		if (ifd->queued_ < ifd->maxqueued_ && ifd->restart != NULL) {
1556 			CBQTRACE(rmc_restart, 'trts', cl->stats_.handle);
1557 			(ifd->restart)(ifd->ifq_);
1558 		}
1559 	}
1560 	IFQ_UNLOCK(ifd->ifq_);
1561 	splx(s);
1562 }
1563 
1564 /*
1565  * void
1566  * rmc_root_overlimit(struct rm_class *cl) - This the generic overlimit
1567  *	handling routine for the root class of the link sharing structure.
1568  *
1569  *	Returns: NONE
1570  */
1571 
1572 static void
1573 rmc_root_overlimit(struct rm_class *cl, struct rm_class *borrow)
1574 {
1575     panic("rmc_root_overlimit");
1576 }
1577 
1578 /*
1579  * Packet Queue handling routines.  Eventually, this is to localize the
1580  *	effects on the code whether queues are red queues or droptail
1581  *	queues.
1582  */
1583 
1584 static int
1585 _rmc_addq(rm_class_t *cl, mbuf_t *m)
1586 {
1587 #ifdef ALTQ_RIO
1588 	if (q_is_rio(cl->q_))
1589 		return rio_addq((rio_t *)cl->red_, cl->q_, m, cl->pktattr_);
1590 #endif
1591 #ifdef ALTQ_RED
1592 	if (q_is_red(cl->q_))
1593 		return red_addq(cl->red_, cl->q_, m, cl->pktattr_);
1594 #endif /* ALTQ_RED */
1595 
1596 	if (cl->flags_ & RMCF_CLEARDSCP)
1597 		write_dsfield(m, cl->pktattr_, 0);
1598 
1599 	_addq(cl->q_, m);
1600 	return (0);
1601 }
1602 
1603 /* note: _rmc_dropq is not called for red */
1604 static void
1605 _rmc_dropq(rm_class_t *cl)
1606 {
1607 	mbuf_t	*m;
1608 
1609 	if ((m = _getq(cl->q_)) != NULL)
1610 		m_freem(m);
1611 }
1612 
1613 static mbuf_t *
1614 _rmc_getq(rm_class_t *cl)
1615 {
1616 #ifdef ALTQ_RIO
1617 	if (q_is_rio(cl->q_))
1618 		return rio_getq((rio_t *)cl->red_, cl->q_);
1619 #endif
1620 #ifdef ALTQ_RED
1621 	if (q_is_red(cl->q_))
1622 		return red_getq(cl->red_, cl->q_);
1623 #endif
1624 	return _getq(cl->q_);
1625 }
1626 
1627 static mbuf_t *
1628 _rmc_pollq(rm_class_t *cl)
1629 {
1630 	return qhead(cl->q_);
1631 }
1632 
1633 #ifdef CBQ_TRACE
1634 
1635 struct cbqtrace		 cbqtrace_buffer[NCBQTRACE+1];
1636 struct cbqtrace		*cbqtrace_ptr = NULL;
1637 int			 cbqtrace_count;
1638 
1639 /*
1640  * DDB hook to trace cbq events:
1641  *  the last 1024 events are held in a circular buffer.
1642  *  use "call cbqtrace_dump(N)" to display 20 events from Nth event.
1643  */
1644 void cbqtrace_dump(int);
1645 static char *rmc_funcname(void *);
1646 
1647 static struct rmc_funcs {
1648 	void	*func;
1649 	char	*name;
1650 } rmc_funcs[] =
1651 {
1652 	rmc_init,		"rmc_init",
1653 	rmc_queue_packet,	"rmc_queue_packet",
1654 	rmc_under_limit,	"rmc_under_limit",
1655 	rmc_update_class_util,	"rmc_update_class_util",
1656 	rmc_delay_action,	"rmc_delay_action",
1657 	rmc_restart,		"rmc_restart",
1658 	_rmc_wrr_dequeue_next,	"_rmc_wrr_dequeue_next",
1659 	NULL,			NULL
1660 };
1661 
1662 static char *rmc_funcname(void *func)
1663 {
1664 	struct rmc_funcs *fp;
1665 
1666 	for (fp = rmc_funcs; fp->func != NULL; fp++)
1667 		if (fp->func == func)
1668 			return (fp->name);
1669 	return ("unknown");
1670 }
1671 
1672 void cbqtrace_dump(int counter)
1673 {
1674 	int	 i, *p;
1675 	char	*cp;
1676 
1677 	counter = counter % NCBQTRACE;
1678 	p = (int *)&cbqtrace_buffer[counter];
1679 
1680 	for (i=0; i<20; i++) {
1681 		printf("[0x%x] ", *p++);
1682 		printf("%s: ", rmc_funcname((void *)*p++));
1683 		cp = (char *)p++;
1684 		printf("%c%c%c%c: ", cp[0], cp[1], cp[2], cp[3]);
1685 		printf("%d\n",*p++);
1686 
1687 		if (p >= (int *)&cbqtrace_buffer[NCBQTRACE])
1688 			p = (int *)cbqtrace_buffer;
1689 	}
1690 }
1691 #endif /* CBQ_TRACE */
1692 #endif /* ALTQ_CBQ */
1693 
1694 #if defined(ALTQ_CBQ) || defined(ALTQ_RED) || defined(ALTQ_RIO) || defined(ALTQ_HFSC) || defined(ALTQ_PRIQ)
1695 #if !defined(__GNUC__) || defined(ALTQ_DEBUG)
1696 
1697 void
1698 _addq(class_queue_t *q, mbuf_t *m)
1699 {
1700         mbuf_t	*m0;
1701 
1702 	if ((m0 = qtail(q)) != NULL)
1703 		m->m_nextpkt = m0->m_nextpkt;
1704 	else
1705 		m0 = m;
1706 	m0->m_nextpkt = m;
1707 	qtail(q) = m;
1708 	qlen(q)++;
1709 }
1710 
1711 mbuf_t *
1712 _getq(class_queue_t *q)
1713 {
1714 	mbuf_t	*m, *m0;
1715 
1716 	if ((m = qtail(q)) == NULL)
1717 		return (NULL);
1718 	if ((m0 = m->m_nextpkt) != m)
1719 		m->m_nextpkt = m0->m_nextpkt;
1720 	else {
1721 		ASSERT(qlen(q) == 1);
1722 		qtail(q) = NULL;
1723 	}
1724 	qlen(q)--;
1725 	m0->m_nextpkt = NULL;
1726 	return (m0);
1727 }
1728 
1729 /* drop a packet at the tail of the queue */
1730 mbuf_t *
1731 _getq_tail(class_queue_t *q)
1732 {
1733 	mbuf_t	*m, *m0, *prev;
1734 
1735 	if ((m = m0 = qtail(q)) == NULL)
1736 		return NULL;
1737 	do {
1738 		prev = m0;
1739 		m0 = m0->m_nextpkt;
1740 	} while (m0 != m);
1741 	prev->m_nextpkt = m->m_nextpkt;
1742 	if (prev == m)  {
1743 		ASSERT(qlen(q) == 1);
1744 		qtail(q) = NULL;
1745 	} else
1746 		qtail(q) = prev;
1747 	qlen(q)--;
1748 	m->m_nextpkt = NULL;
1749 	return (m);
1750 }
1751 
1752 /* randomly select a packet in the queue */
1753 mbuf_t *
1754 _getq_random(class_queue_t *q)
1755 {
1756 	struct mbuf	*m;
1757 	int		 i, n;
1758 
1759 	if ((m = qtail(q)) == NULL)
1760 		return NULL;
1761 	if (m->m_nextpkt == m) {
1762 		ASSERT(qlen(q) == 1);
1763 		qtail(q) = NULL;
1764 	} else {
1765 		struct mbuf *prev = NULL;
1766 
1767 		n = arc4random() % qlen(q) + 1;
1768 		for (i = 0; i < n; i++) {
1769 			prev = m;
1770 			m = m->m_nextpkt;
1771 		}
1772 		prev->m_nextpkt = m->m_nextpkt;
1773 		if (m == qtail(q))
1774 			qtail(q) = prev;
1775 	}
1776 	qlen(q)--;
1777 	m->m_nextpkt = NULL;
1778 	return (m);
1779 }
1780 
1781 void
1782 _removeq(class_queue_t *q, mbuf_t *m)
1783 {
1784 	mbuf_t	*m0, *prev;
1785 
1786 	m0 = qtail(q);
1787 	do {
1788 		prev = m0;
1789 		m0 = m0->m_nextpkt;
1790 	} while (m0 != m);
1791 	prev->m_nextpkt = m->m_nextpkt;
1792 	if (prev == m)
1793 		qtail(q) = NULL;
1794 	else if (qtail(q) == m)
1795 		qtail(q) = prev;
1796 	qlen(q)--;
1797 }
1798 
1799 void
1800 _flushq(class_queue_t *q)
1801 {
1802 	mbuf_t *m;
1803 
1804 	while ((m = _getq(q)) != NULL)
1805 		m_freem(m);
1806 	ASSERT(qlen(q) == 0);
1807 }
1808 
1809 #endif /* !__GNUC__ || ALTQ_DEBUG */
1810 #endif /* ALTQ_CBQ || ALTQ_RED || ALTQ_RIO || ALTQ_HFSC || ALTQ_PRIQ */
1811