xref: /dflybsd-src/sys/net/altq/altq_subr.c (revision c4bf625e67439f34b29bfd33c4e2555ffea63ce9)
1 /*	$KAME: altq_subr.c,v 1.23 2004/04/20 16:10:06 itojun Exp $	*/
2 /*	$DragonFly: src/sys/net/altq/altq_subr.c,v 1.10 2008/04/06 18:58:15 dillon Exp $ */
3 
4 /*
5  * Copyright (C) 1997-2003
6  *	Sony Computer Science Laboratories Inc.  All rights reserved.
7  *
8  * Redistribution and use in source and binary forms, with or without
9  * modification, are permitted provided that the following conditions
10  * are met:
11  * 1. Redistributions of source code must retain the above copyright
12  *    notice, this list of conditions and the following disclaimer.
13  * 2. Redistributions in binary form must reproduce the above copyright
14  *    notice, this list of conditions and the following disclaimer in the
15  *    documentation and/or other materials provided with the distribution.
16  *
17  * THIS SOFTWARE IS PROVIDED BY SONY CSL AND CONTRIBUTORS ``AS IS'' AND
18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20  * ARE DISCLAIMED.  IN NO EVENT SHALL SONY CSL OR CONTRIBUTORS BE LIABLE
21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27  * SUCH DAMAGE.
28  */
29 
30 #include "opt_altq.h"
31 #include "opt_inet.h"
32 #include "opt_inet6.h"
33 
34 #include <sys/param.h>
35 #include <sys/malloc.h>
36 #include <sys/mbuf.h>
37 #include <sys/systm.h>
38 #include <sys/proc.h>
39 #include <sys/socket.h>
40 #include <sys/socketvar.h>
41 #include <sys/kernel.h>
42 #include <sys/callout.h>
43 #include <sys/errno.h>
44 #include <sys/syslog.h>
45 #include <sys/sysctl.h>
46 #include <sys/queue.h>
47 #include <sys/thread2.h>
48 
49 #include <net/if.h>
50 #include <net/if_dl.h>
51 #include <net/if_types.h>
52 #include <net/ifq_var.h>
53 
54 #include <netinet/in.h>
55 #include <netinet/in_systm.h>
56 #include <netinet/ip.h>
57 #ifdef INET6
58 #include <netinet/ip6.h>
59 #endif
60 #include <netinet/tcp.h>
61 #include <netinet/udp.h>
62 
63 #include <net/pf/pfvar.h>
64 #include <net/altq/altq.h>
65 
66 /* machine dependent clock related includes */
67 #if defined(__i386__)
68 #include <machine/clock.h>		/* for tsc_freq */
69 #include <machine/md_var.h>		/* for cpu_feature */
70 #include <machine/specialreg.h>		/* for CPUID_TSC */
71 #endif /* __i386__ */
72 
73 /*
74  * internal function prototypes
75  */
76 static void	tbr_timeout(void *);
77 int (*altq_input)(struct mbuf *, int) = NULL;
78 static int tbr_timer = 0;	/* token bucket regulator timer */
79 static struct callout tbr_callout;
80 
81 int pfaltq_running;	/* keep track of running state */
82 
83 MALLOC_DEFINE(M_ALTQ, "altq", "ALTQ structures");
84 
85 /*
86  * alternate queueing support routines
87  */
88 
89 /* look up the queue state by the interface name and the queueing type. */
90 void *
91 altq_lookup(const char *name, int type)
92 {
93 	struct ifnet *ifp;
94 
95 	if ((ifp = ifunit(name)) != NULL) {
96 		if (type != ALTQT_NONE && ifp->if_snd.altq_type == type)
97 			return (ifp->if_snd.altq_disc);
98 	}
99 
100 	return (NULL);
101 }
102 
103 int
104 altq_attach(struct ifaltq *ifq, int type, void *discipline,
105 	    int (*enqueue)(struct ifaltq *, struct mbuf *, struct altq_pktattr *),
106 	    struct mbuf *(*dequeue)(struct ifaltq *, struct mbuf *, int),
107 	    int (*request)(struct ifaltq *, int, void *),
108 	    void *clfier,
109 	    void *(*classify)(struct ifaltq *, struct mbuf *,
110 			      struct altq_pktattr *))
111 {
112 	if (!ifq_is_ready(ifq))
113 		return ENXIO;
114 
115 	ifq->altq_type     = type;
116 	ifq->altq_disc     = discipline;
117 	ifq->altq_enqueue  = enqueue;
118 	ifq->altq_dequeue  = dequeue;
119 	ifq->altq_request  = request;
120 	ifq->altq_clfier   = clfier;
121 	ifq->altq_classify = classify;
122 	ifq->altq_flags &= (ALTQF_CANTCHANGE|ALTQF_ENABLED);
123 	return 0;
124 }
125 
126 int
127 altq_detach(struct ifaltq *ifq)
128 {
129 	if (!ifq_is_ready(ifq))
130 		return ENXIO;
131 	if (ifq_is_enabled(ifq))
132 		return EBUSY;
133 	if (!ifq_is_attached(ifq))
134 		return (0);
135 
136 	ifq_set_classic(ifq);
137 	ifq->altq_type     = ALTQT_NONE;
138 	ifq->altq_disc     = NULL;
139 	ifq->altq_clfier   = NULL;
140 	ifq->altq_classify = NULL;
141 	ifq->altq_flags &= ALTQF_CANTCHANGE;
142 	return 0;
143 }
144 
145 int
146 altq_enable(struct ifaltq *ifq)
147 {
148 	if (!ifq_is_ready(ifq))
149 		return ENXIO;
150 	if (ifq_is_enabled(ifq))
151 		return 0;
152 
153 	crit_enter();
154 	ifq_purge(ifq);
155 	KKASSERT(ifq->ifq_len == 0);
156 	ifq->altq_flags |= ALTQF_ENABLED;
157 	if (ifq->altq_clfier != NULL)
158 		ifq->altq_flags |= ALTQF_CLASSIFY;
159 	crit_exit();
160 
161 	return 0;
162 }
163 
164 int
165 altq_disable(struct ifaltq *ifq)
166 {
167 	if (!ifq_is_enabled(ifq))
168 		return 0;
169 
170 	crit_enter();
171 	ifq_purge(ifq);
172 	KKASSERT(ifq->ifq_len == 0);
173 	ifq->altq_flags &= ~(ALTQF_ENABLED|ALTQF_CLASSIFY);
174 	crit_exit();
175 	return 0;
176 }
177 
178 /*
179  * internal representation of token bucket parameters
180  *	rate:	byte_per_unittime << 32
181  *		(((bits_per_sec) / 8) << 32) / machclk_freq
182  *	depth:	byte << 32
183  *
184  */
185 #define	TBR_SHIFT	32
186 #define	TBR_SCALE(x)	((int64_t)(x) << TBR_SHIFT)
187 #define	TBR_UNSCALE(x)	((x) >> TBR_SHIFT)
188 
189 struct mbuf *
190 tbr_dequeue(struct ifaltq *ifq, struct mbuf *mpolled, int op)
191 {
192 	struct tb_regulator *tbr;
193 	struct mbuf *m;
194 	int64_t interval;
195 	uint64_t now;
196 
197 	crit_enter();
198 	tbr = ifq->altq_tbr;
199 	if (op == ALTDQ_REMOVE && tbr->tbr_lastop == ALTDQ_POLL) {
200 		/* if this is a remove after poll, bypass tbr check */
201 	} else {
202 		/* update token only when it is negative */
203 		if (tbr->tbr_token <= 0) {
204 			now = read_machclk();
205 			interval = now - tbr->tbr_last;
206 			if (interval >= tbr->tbr_filluptime)
207 				tbr->tbr_token = tbr->tbr_depth;
208 			else {
209 				tbr->tbr_token += interval * tbr->tbr_rate;
210 				if (tbr->tbr_token > tbr->tbr_depth)
211 					tbr->tbr_token = tbr->tbr_depth;
212 			}
213 			tbr->tbr_last = now;
214 		}
215 		/* if token is still negative, don't allow dequeue */
216 		if (tbr->tbr_token <= 0) {
217 			crit_exit();
218 			return (NULL);
219 		}
220 	}
221 
222 	if (ifq_is_enabled(ifq)) {
223 		m = (*ifq->altq_dequeue)(ifq, mpolled, op);
224 	} else if (op == ALTDQ_POLL) {
225 		IF_POLL(ifq, m);
226 	} else {
227 		IF_DEQUEUE(ifq, m);
228 		KKASSERT(mpolled == NULL || mpolled == m);
229 	}
230 
231 	if (m != NULL && op == ALTDQ_REMOVE)
232 		tbr->tbr_token -= TBR_SCALE(m_pktlen(m));
233 	tbr->tbr_lastop = op;
234 	crit_exit();
235 	return (m);
236 }
237 
238 /*
239  * set a token bucket regulator.
240  * if the specified rate is zero, the token bucket regulator is deleted.
241  */
242 int
243 tbr_set(struct ifaltq *ifq, struct tb_profile *profile)
244 {
245 	struct tb_regulator *tbr, *otbr;
246 
247 	if (machclk_freq == 0)
248 		init_machclk();
249 	if (machclk_freq == 0) {
250 		kprintf("tbr_set: no cpu clock available!\n");
251 		return (ENXIO);
252 	}
253 
254 	if (profile->rate == 0) {
255 		/* delete this tbr */
256 		if ((tbr = ifq->altq_tbr) == NULL)
257 			return (ENOENT);
258 		ifq->altq_tbr = NULL;
259 		kfree(tbr, M_ALTQ);
260 		return (0);
261 	}
262 
263 	tbr = kmalloc(sizeof(*tbr), M_ALTQ, M_WAITOK | M_ZERO);
264 	tbr->tbr_rate = TBR_SCALE(profile->rate / 8) / machclk_freq;
265 	tbr->tbr_depth = TBR_SCALE(profile->depth);
266 	if (tbr->tbr_rate > 0)
267 		tbr->tbr_filluptime = tbr->tbr_depth / tbr->tbr_rate;
268 	else
269 		tbr->tbr_filluptime = 0xffffffffffffffffLL;
270 	tbr->tbr_token = tbr->tbr_depth;
271 	tbr->tbr_last = read_machclk();
272 	tbr->tbr_lastop = ALTDQ_REMOVE;
273 
274 	otbr = ifq->altq_tbr;
275 	ifq->altq_tbr = tbr;	/* set the new tbr */
276 
277 	if (otbr != NULL)
278 		kfree(otbr, M_ALTQ);
279 	else if (tbr_timer == 0) {
280 		callout_reset(&tbr_callout, 1, tbr_timeout, NULL);
281 		tbr_timer = 1;
282 	}
283 	return (0);
284 }
285 
286 /*
287  * tbr_timeout goes through the interface list, and kicks the drivers
288  * if necessary.
289  */
290 static void
291 tbr_timeout(void *arg)
292 {
293 	struct ifnet *ifp;
294 	int active;
295 
296 	active = 0;
297 	crit_enter();
298 	for (ifp = TAILQ_FIRST(&ifnet); ifp; ifp = TAILQ_NEXT(ifp, if_list)) {
299 		if (ifp->if_snd.altq_tbr == NULL)
300 			continue;
301 		active++;
302 		if (!ifq_is_empty(&ifp->if_snd) && ifp->if_start != NULL) {
303 			lwkt_serialize_enter(ifp->if_serializer);
304 			(*ifp->if_start)(ifp);
305 			lwkt_serialize_exit(ifp->if_serializer);
306 		}
307 	}
308 	crit_exit();
309 	if (active > 0)
310 		callout_reset(&tbr_callout, 1, tbr_timeout, NULL);
311 	else
312 		tbr_timer = 0;	/* don't need tbr_timer anymore */
313 }
314 
315 /*
316  * get token bucket regulator profile
317  */
318 int
319 tbr_get(struct ifaltq *ifq, struct tb_profile *profile)
320 {
321 	struct tb_regulator *tbr;
322 
323 	if ((tbr = ifq->altq_tbr) == NULL) {
324 		profile->rate = 0;
325 		profile->depth = 0;
326 	} else {
327 		profile->rate =
328 		    (u_int)TBR_UNSCALE(tbr->tbr_rate * 8 * machclk_freq);
329 		profile->depth = (u_int)TBR_UNSCALE(tbr->tbr_depth);
330 	}
331 	return (0);
332 }
333 
334 /*
335  * attach a discipline to the interface.  if one already exists, it is
336  * overridden.
337  */
338 int
339 altq_pfattach(struct pf_altq *a)
340 {
341 	struct ifnet *ifp;
342 	struct tb_profile tb;
343 	int error = 0;
344 
345 	switch (a->scheduler) {
346 	case ALTQT_NONE:
347 		break;
348 #ifdef ALTQ_CBQ
349 	case ALTQT_CBQ:
350 		error = cbq_pfattach(a);
351 		break;
352 #endif
353 #ifdef ALTQ_PRIQ
354 	case ALTQT_PRIQ:
355 		error = priq_pfattach(a);
356 		break;
357 #endif
358 #ifdef ALTQ_HFSC
359 	case ALTQT_HFSC:
360 		error = hfsc_pfattach(a);
361 		break;
362 #endif
363 #ifdef ALTQ_FAIRQ
364 	case ALTQT_FAIRQ:
365 		error = fairq_pfattach(a);
366 		break;
367 #endif
368 	default:
369 		error = ENXIO;
370 	}
371 
372 	ifp = ifunit(a->ifname);
373 
374 	/* if the state is running, enable altq */
375 	if (error == 0 && pfaltq_running &&
376 	    ifp != NULL && ifp->if_snd.altq_type != ALTQT_NONE &&
377 	    !ifq_is_enabled(&ifp->if_snd))
378 			error = altq_enable(&ifp->if_snd);
379 
380 	/* if altq is already enabled, reset set tokenbucket regulator */
381 	if (error == 0 && ifp != NULL && ifq_is_enabled(&ifp->if_snd)) {
382 		tb.rate = a->ifbandwidth;
383 		tb.depth = a->tbrsize;
384 		crit_enter();
385 		error = tbr_set(&ifp->if_snd, &tb);
386 		crit_exit();
387 	}
388 
389 	return (error);
390 }
391 
392 /*
393  * detach a discipline from the interface.
394  * it is possible that the discipline was already overridden by another
395  * discipline.
396  */
397 int
398 altq_pfdetach(struct pf_altq *a)
399 {
400 	struct ifnet *ifp;
401 	int error = 0;
402 
403 	if ((ifp = ifunit(a->ifname)) == NULL)
404 		return (EINVAL);
405 
406 	/* if this discipline is no longer referenced, just return */
407 	if (a->altq_disc == NULL || a->altq_disc != ifp->if_snd.altq_disc)
408 		return (0);
409 
410 	crit_enter();
411 	if (ifq_is_enabled(&ifp->if_snd))
412 		error = altq_disable(&ifp->if_snd);
413 	if (error == 0)
414 		error = altq_detach(&ifp->if_snd);
415 	crit_exit();
416 
417 	return (error);
418 }
419 
420 /*
421  * add a discipline or a queue
422  */
423 int
424 altq_add(struct pf_altq *a)
425 {
426 	int error = 0;
427 
428 	if (a->qname[0] != 0)
429 		return (altq_add_queue(a));
430 
431 	if (machclk_freq == 0)
432 		init_machclk();
433 	if (machclk_freq == 0)
434 		panic("altq_add: no cpu clock");
435 
436 	switch (a->scheduler) {
437 #ifdef ALTQ_CBQ
438 	case ALTQT_CBQ:
439 		error = cbq_add_altq(a);
440 		break;
441 #endif
442 #ifdef ALTQ_PRIQ
443 	case ALTQT_PRIQ:
444 		error = priq_add_altq(a);
445 		break;
446 #endif
447 #ifdef ALTQ_HFSC
448 	case ALTQT_HFSC:
449 		error = hfsc_add_altq(a);
450 		break;
451 #endif
452 #ifdef ALTQ_FAIRQ
453 	case ALTQT_FAIRQ:
454 		error = fairq_add_altq(a);
455 		break;
456 #endif
457 	default:
458 		error = ENXIO;
459 	}
460 
461 	return (error);
462 }
463 
464 /*
465  * remove a discipline or a queue
466  */
467 int
468 altq_remove(struct pf_altq *a)
469 {
470 	int error = 0;
471 
472 	if (a->qname[0] != 0)
473 		return (altq_remove_queue(a));
474 
475 	switch (a->scheduler) {
476 #ifdef ALTQ_CBQ
477 	case ALTQT_CBQ:
478 		error = cbq_remove_altq(a);
479 		break;
480 #endif
481 #ifdef ALTQ_PRIQ
482 	case ALTQT_PRIQ:
483 		error = priq_remove_altq(a);
484 		break;
485 #endif
486 #ifdef ALTQ_HFSC
487 	case ALTQT_HFSC:
488 		error = hfsc_remove_altq(a);
489 		break;
490 #endif
491 #ifdef ALTQ_FAIRQ
492 	case ALTQT_FAIRQ:
493 		error = fairq_remove_altq(a);
494 		break;
495 #endif
496 	default:
497 		error = ENXIO;
498 	}
499 
500 	return (error);
501 }
502 
503 /*
504  * add a queue to the discipline
505  */
506 int
507 altq_add_queue(struct pf_altq *a)
508 {
509 	int error = 0;
510 
511 	switch (a->scheduler) {
512 #ifdef ALTQ_CBQ
513 	case ALTQT_CBQ:
514 		error = cbq_add_queue(a);
515 		break;
516 #endif
517 #ifdef ALTQ_PRIQ
518 	case ALTQT_PRIQ:
519 		error = priq_add_queue(a);
520 		break;
521 #endif
522 #ifdef ALTQ_HFSC
523 	case ALTQT_HFSC:
524 		error = hfsc_add_queue(a);
525 		break;
526 #endif
527 #ifdef ALTQ_FAIRQ
528 	case ALTQT_FAIRQ:
529 		error = fairq_add_queue(a);
530 		break;
531 #endif
532 	default:
533 		error = ENXIO;
534 	}
535 
536 	return (error);
537 }
538 
539 /*
540  * remove a queue from the discipline
541  */
542 int
543 altq_remove_queue(struct pf_altq *a)
544 {
545 	int error = 0;
546 
547 	switch (a->scheduler) {
548 #ifdef ALTQ_CBQ
549 	case ALTQT_CBQ:
550 		error = cbq_remove_queue(a);
551 		break;
552 #endif
553 #ifdef ALTQ_PRIQ
554 	case ALTQT_PRIQ:
555 		error = priq_remove_queue(a);
556 		break;
557 #endif
558 #ifdef ALTQ_HFSC
559 	case ALTQT_HFSC:
560 		error = hfsc_remove_queue(a);
561 		break;
562 #endif
563 #ifdef ALTQ_FAIRQ
564 	case ALTQT_FAIRQ:
565 		error = fairq_remove_queue(a);
566 		break;
567 #endif
568 	default:
569 		error = ENXIO;
570 	}
571 
572 	return (error);
573 }
574 
575 /*
576  * get queue statistics
577  */
578 int
579 altq_getqstats(struct pf_altq *a, void *ubuf, int *nbytes)
580 {
581 	int error = 0;
582 
583 	switch (a->scheduler) {
584 #ifdef ALTQ_CBQ
585 	case ALTQT_CBQ:
586 		error = cbq_getqstats(a, ubuf, nbytes);
587 		break;
588 #endif
589 #ifdef ALTQ_PRIQ
590 	case ALTQT_PRIQ:
591 		error = priq_getqstats(a, ubuf, nbytes);
592 		break;
593 #endif
594 #ifdef ALTQ_HFSC
595 	case ALTQT_HFSC:
596 		error = hfsc_getqstats(a, ubuf, nbytes);
597 		break;
598 #endif
599 #ifdef ALTQ_FAIRQ
600 	case ALTQT_FAIRQ:
601 		error = fairq_getqstats(a, ubuf, nbytes);
602 		break;
603 #endif
604 	default:
605 		error = ENXIO;
606 	}
607 
608 	return (error);
609 }
610 
611 /*
612  * read and write diffserv field in IPv4 or IPv6 header
613  */
614 uint8_t
615 read_dsfield(struct mbuf *m, struct altq_pktattr *pktattr)
616 {
617 	struct mbuf *m0;
618 	uint8_t ds_field = 0;
619 
620 	if (pktattr == NULL ||
621 	    (pktattr->pattr_af != AF_INET && pktattr->pattr_af != AF_INET6))
622 		return ((uint8_t)0);
623 
624 	/* verify that pattr_hdr is within the mbuf data */
625 	for (m0 = m; m0 != NULL; m0 = m0->m_next) {
626 		if ((pktattr->pattr_hdr >= m0->m_data) &&
627 		    (pktattr->pattr_hdr < m0->m_data + m0->m_len))
628 			break;
629 	}
630 	if (m0 == NULL) {
631 		/* ick, pattr_hdr is stale */
632 		pktattr->pattr_af = AF_UNSPEC;
633 #ifdef ALTQ_DEBUG
634 		kprintf("read_dsfield: can't locate header!\n");
635 #endif
636 		return ((uint8_t)0);
637 	}
638 
639 	if (pktattr->pattr_af == AF_INET) {
640 		struct ip *ip = (struct ip *)pktattr->pattr_hdr;
641 
642 		if (ip->ip_v != 4)
643 			return ((uint8_t)0);	/* version mismatch! */
644 		ds_field = ip->ip_tos;
645 	}
646 #ifdef INET6
647 	else if (pktattr->pattr_af == AF_INET6) {
648 		struct ip6_hdr *ip6 = (struct ip6_hdr *)pktattr->pattr_hdr;
649 		uint32_t flowlabel;
650 
651 		flowlabel = ntohl(ip6->ip6_flow);
652 		if ((flowlabel >> 28) != 6)
653 			return ((uint8_t)0);	/* version mismatch! */
654 		ds_field = (flowlabel >> 20) & 0xff;
655 	}
656 #endif
657 	return (ds_field);
658 }
659 
660 void
661 write_dsfield(struct mbuf *m, struct altq_pktattr *pktattr, uint8_t dsfield)
662 {
663 	struct mbuf *m0;
664 
665 	if (pktattr == NULL ||
666 	    (pktattr->pattr_af != AF_INET && pktattr->pattr_af != AF_INET6))
667 		return;
668 
669 	/* verify that pattr_hdr is within the mbuf data */
670 	for (m0 = m; m0 != NULL; m0 = m0->m_next) {
671 		if ((pktattr->pattr_hdr >= m0->m_data) &&
672 		    (pktattr->pattr_hdr < m0->m_data + m0->m_len))
673 			break;
674 	}
675 	if (m0 == NULL) {
676 		/* ick, pattr_hdr is stale */
677 		pktattr->pattr_af = AF_UNSPEC;
678 #ifdef ALTQ_DEBUG
679 		kprintf("write_dsfield: can't locate header!\n");
680 #endif
681 		return;
682 	}
683 
684 	if (pktattr->pattr_af == AF_INET) {
685 		struct ip *ip = (struct ip *)pktattr->pattr_hdr;
686 		uint8_t old;
687 		int32_t sum;
688 
689 		if (ip->ip_v != 4)
690 			return;		/* version mismatch! */
691 		old = ip->ip_tos;
692 		dsfield |= old & 3;	/* leave CU bits */
693 		if (old == dsfield)
694 			return;
695 		ip->ip_tos = dsfield;
696 		/*
697 		 * update checksum (from RFC1624)
698 		 *	   HC' = ~(~HC + ~m + m')
699 		 */
700 		sum = ~ntohs(ip->ip_sum) & 0xffff;
701 		sum += 0xff00 + (~old & 0xff) + dsfield;
702 		sum = (sum >> 16) + (sum & 0xffff);
703 		sum += (sum >> 16);  /* add carry */
704 
705 		ip->ip_sum = htons(~sum & 0xffff);
706 	}
707 #ifdef INET6
708 	else if (pktattr->pattr_af == AF_INET6) {
709 		struct ip6_hdr *ip6 = (struct ip6_hdr *)pktattr->pattr_hdr;
710 		uint32_t flowlabel;
711 
712 		flowlabel = ntohl(ip6->ip6_flow);
713 		if ((flowlabel >> 28) != 6)
714 			return;		/* version mismatch! */
715 		flowlabel = (flowlabel & 0xf03fffff) | (dsfield << 20);
716 		ip6->ip6_flow = htonl(flowlabel);
717 	}
718 #endif
719 }
720 
721 /*
722  * high resolution clock support taking advantage of a machine dependent
723  * high resolution time counter (e.g., timestamp counter of intel pentium).
724  * we assume
725  *  - 64-bit-long monotonically-increasing counter
726  *  - frequency range is 100M-4GHz (CPU speed)
727  */
728 /* if pcc is not available or disabled, emulate 256MHz using microtime() */
729 #define	MACHCLK_SHIFT	8
730 
731 int machclk_usepcc;
732 uint32_t machclk_freq = 0;
733 uint32_t machclk_per_tick = 0;
734 
735 void
736 init_machclk(void)
737 {
738 	callout_init(&tbr_callout);
739 
740 	machclk_usepcc = 1;
741 
742 #if !defined(__i386__) || defined(ALTQ_NOPCC)
743 	machclk_usepcc = 0;
744 #elif defined(__DragonFly__) && defined(SMP)
745 	machclk_usepcc = 0;
746 #elif defined(__i386__)
747 	/* check if TSC is available */
748 	if (machclk_usepcc == 1 && (cpu_feature & CPUID_TSC) == 0)
749 		machclk_usepcc = 0;
750 #endif
751 
752 	if (machclk_usepcc == 0) {
753 		/* emulate 256MHz using microtime() */
754 		machclk_freq = 1000000 << MACHCLK_SHIFT;
755 		machclk_per_tick = machclk_freq / hz;
756 #ifdef ALTQ_DEBUG
757 		kprintf("altq: emulate %uHz cpu clock\n", machclk_freq);
758 #endif
759 		return;
760 	}
761 
762 	/*
763 	 * if the clock frequency (of Pentium TSC or Alpha PCC) is
764 	 * accessible, just use it.
765 	 */
766 #ifdef __i386__
767 	machclk_freq = tsc_freq;
768 #else
769 #error "machclk_freq interface not implemented"
770 #endif
771 
772 	/*
773 	 * if we don't know the clock frequency, measure it.
774 	 */
775 	if (machclk_freq == 0) {
776 		static int	wait;
777 		struct timeval	tv_start, tv_end;
778 		uint64_t	start, end, diff;
779 		int		timo;
780 
781 		microtime(&tv_start);
782 		start = read_machclk();
783 		timo = hz;	/* 1 sec */
784 		tsleep(&wait, PCATCH, "init_machclk", timo);
785 		microtime(&tv_end);
786 		end = read_machclk();
787 		diff = (uint64_t)(tv_end.tv_sec - tv_start.tv_sec) * 1000000
788 		    + tv_end.tv_usec - tv_start.tv_usec;
789 		if (diff != 0)
790 			machclk_freq = (u_int)((end - start) * 1000000 / diff);
791 	}
792 
793 	machclk_per_tick = machclk_freq / hz;
794 
795 #ifdef ALTQ_DEBUG
796 	kprintf("altq: CPU clock: %uHz\n", machclk_freq);
797 #endif
798 }
799 
800 uint64_t
801 read_machclk(void)
802 {
803 	uint64_t val;
804 
805 	if (machclk_usepcc) {
806 #if defined(__i386__)
807 		val = rdtsc();
808 #else
809 		panic("read_machclk");
810 #endif
811 	} else {
812 		struct timeval tv;
813 
814 		microtime(&tv);
815 		val = (((uint64_t)(tv.tv_sec - boottime.tv_sec) * 1000000
816 		    + tv.tv_usec) << MACHCLK_SHIFT);
817 	}
818 	return (val);
819 }
820