xref: /netbsd-src/sys/altq/altq_blue.c (revision 0633b543c2bc91e93b550ec10f8042775c1b1b4c)
1 /*	$NetBSD: altq_blue.c,v 1.27 2025/01/08 13:00:04 joe Exp $	*/
2 /*	$KAME: altq_blue.c,v 1.15 2005/04/13 03:44:24 suz Exp $	*/
3 
4 /*
5  * Copyright (C) 1997-2002
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 /*
31  * Copyright (c) 1990-1994 Regents of the University of California.
32  * All rights reserved.
33  *
34  * Redistribution and use in source and binary forms, with or without
35  * modification, are permitted provided that the following conditions
36  * are met:
37  * 1. Redistributions of source code must retain the above copyright
38  *    notice, this list of conditions and the following disclaimer.
39  * 2. Redistributions in binary form must reproduce the above copyright
40  *    notice, this list of conditions and the following disclaimer in the
41  *    documentation and/or other materials provided with the distribution.
42  * 3. All advertising materials mentioning features or use of this software
43  *    must display the following acknowledgement:
44  *	This product includes software developed by the Computer Systems
45  *	Engineering Group at Lawrence Berkeley Laboratory.
46  * 4. Neither the name of the University nor of the Laboratory may be used
47  *    to endorse or promote products derived from this software without
48  *    specific prior written permission.
49  *
50  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
51  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
52  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
53  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
54  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
55  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
56  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
57  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
58  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
59  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
60  * SUCH DAMAGE.
61  */
62 
63 #include <sys/cdefs.h>
64 __KERNEL_RCSID(0, "$NetBSD: altq_blue.c,v 1.27 2025/01/08 13:00:04 joe Exp $");
65 
66 #ifdef _KERNEL_OPT
67 #include "opt_altq.h"
68 #include "opt_inet.h"
69 #endif
70 
71 #ifdef ALTQ_BLUE	/* blue is enabled by ALTQ_BLUE option in opt_altq.h */
72 
73 #include <sys/param.h>
74 #include <sys/malloc.h>
75 #include <sys/mbuf.h>
76 #include <sys/socket.h>
77 #include <sys/sockio.h>
78 #include <sys/systm.h>
79 #include <sys/proc.h>
80 #include <sys/errno.h>
81 #include <sys/kernel.h>
82 #include <sys/kauth.h>
83 #include <sys/cprng.h>
84 
85 #include <net/if.h>
86 #include <net/if_types.h>
87 #include <netinet/in.h>
88 #include <netinet/in_systm.h>
89 #include <netinet/ip.h>
90 #ifdef INET6
91 #include <netinet/ip6.h>
92 #endif
93 
94 #include <altq/altq.h>
95 #include <altq/altq_conf.h>
96 #include <altq/altq_blue.h>
97 
98 #ifdef ALTQ3_COMPAT
99 /*
100  * Blue is proposed and implemented by Wu-chang Feng <wuchang@eecs.umich.edu>.
101  * more information on Blue is available from
102  * http://www.eecs.umich.edu/~wuchang/blue/
103  */
104 
105 /* fixed-point uses 12-bit decimal places */
106 #define	FP_SHIFT	12	/* fixed-point shift */
107 
108 #define	BLUE_LIMIT	200	/* default max queue length */
109 #define	BLUE_STATS		/* collect statistics */
110 
111 /* blue_list keeps all blue_state_t's allocated. */
112 static blue_queue_t *blue_list = NULL;
113 
114 /* internal function prototypes */
115 static int blue_enqueue(struct ifaltq *, struct mbuf *);
116 static struct mbuf *blue_dequeue(struct ifaltq *, int);
117 static int drop_early(blue_t *);
118 static int mark_ecn(struct mbuf *, struct altq_pktattr *, int);
119 static int blue_detach(blue_queue_t *);
120 static int blue_request(struct ifaltq *, int, void *);
121 
122 /*
123  * blue device interface
124  */
125 altqdev_decl(blue);
126 
127 int
128 blueopen(dev_t dev, int flag, int fmt,
129     struct lwp *l)
130 {
131 	/* everything will be done when the queueing scheme is attached. */
132 	return 0;
133 }
134 
135 int
136 blueclose(dev_t dev, int flag, int fmt,
137     struct lwp *l)
138 {
139 	blue_queue_t *rqp;
140 	int err, error = 0;
141 
142 	while ((rqp = blue_list) != NULL) {
143 		/* destroy all */
144 		err = blue_detach(rqp);
145 		if (err != 0 && error == 0)
146 			error = err;
147 	}
148 
149 	return error;
150 }
151 
152 int
153 blueioctl(dev_t dev, ioctlcmd_t cmd, void *addr, int flag,
154     struct lwp *l)
155 {
156 	blue_queue_t *rqp;
157 	struct blue_interface *ifacep;
158 	struct ifnet *ifp;
159 	int	error = 0;
160 
161 	/* check super-user privilege */
162 	switch (cmd) {
163 	case BLUE_GETSTATS:
164 		break;
165 	default:
166 		if ((error = kauth_authorize_network(l->l_cred,
167 		    KAUTH_NETWORK_ALTQ, KAUTH_REQ_NETWORK_ALTQ_BLUE, NULL,
168 		    NULL, NULL)) != 0)
169 			return (error);
170 		break;
171 	}
172 
173 	switch (cmd) {
174 
175 	case BLUE_ENABLE:
176 		ifacep = (struct blue_interface *)addr;
177 		if ((rqp = altq_lookup(ifacep->blue_ifname, ALTQT_BLUE)) == NULL) {
178 			error = EBADF;
179 			break;
180 		}
181 		error = altq_enable(rqp->rq_ifq);
182 		break;
183 
184 	case BLUE_DISABLE:
185 		ifacep = (struct blue_interface *)addr;
186 		if ((rqp = altq_lookup(ifacep->blue_ifname, ALTQT_BLUE)) == NULL) {
187 			error = EBADF;
188 			break;
189 		}
190 		error = altq_disable(rqp->rq_ifq);
191 		break;
192 
193 	case BLUE_IF_ATTACH:
194 		ifp = ifunit(((struct blue_interface *)addr)->blue_ifname);
195 		if (ifp == NULL) {
196 			error = ENXIO;
197 			break;
198 		}
199 
200 		/* allocate and initialize blue_state_t */
201 		rqp = malloc(sizeof(blue_queue_t), M_DEVBUF, M_WAITOK|M_ZERO);
202 		if (rqp == NULL) {
203 			error = ENOMEM;
204 			break;
205 		}
206 
207 		rqp->rq_q = malloc(sizeof(class_queue_t), M_DEVBUF,
208 		    M_WAITOK|M_ZERO);
209 		if (rqp->rq_q == NULL) {
210 			free(rqp, M_DEVBUF);
211 			error = ENOMEM;
212 			break;
213 		}
214 
215 		rqp->rq_blue = malloc(sizeof(blue_t), M_DEVBUF,
216 		    M_WAITOK|M_ZERO);
217 		if (rqp->rq_blue == NULL) {
218 			free(rqp->rq_q, M_DEVBUF);
219 			free(rqp, M_DEVBUF);
220 			error = ENOMEM;
221 			break;
222 		}
223 
224 		rqp->rq_ifq = &ifp->if_snd;
225 		qtail(rqp->rq_q) = NULL;
226 		qlen(rqp->rq_q) = 0;
227 		qlimit(rqp->rq_q) = BLUE_LIMIT;
228 
229 		/* default packet time: 1000 bytes / 10Mbps * 8 * 1000000 */
230 		blue_init(rqp->rq_blue, 0, 800, 1000, 50000);
231 
232 		/*
233 		 * set BLUE to this ifnet structure.
234 		 */
235 		error = altq_attach(rqp->rq_ifq, ALTQT_BLUE, rqp,
236 				    blue_enqueue, blue_dequeue, blue_request,
237 				    NULL, NULL);
238 		if (error) {
239 			free(rqp->rq_blue, M_DEVBUF);
240 			free(rqp->rq_q, M_DEVBUF);
241 			free(rqp, M_DEVBUF);
242 			break;
243 		}
244 
245 		/* add this state to the blue list */
246 		rqp->rq_next = blue_list;
247 		blue_list = rqp;
248 		break;
249 
250 	case BLUE_IF_DETACH:
251 		ifacep = (struct blue_interface *)addr;
252 		if ((rqp = altq_lookup(ifacep->blue_ifname, ALTQT_BLUE)) == NULL) {
253 			error = EBADF;
254 			break;
255 		}
256 		error = blue_detach(rqp);
257 		break;
258 
259 	case BLUE_GETSTATS:
260 		do {
261 			struct blue_stats *q_stats;
262 			blue_t *rp;
263 
264 			q_stats = (struct blue_stats *)addr;
265 			if ((rqp = altq_lookup(q_stats->iface.blue_ifname,
266 					     ALTQT_BLUE)) == NULL) {
267 				error = EBADF;
268 				break;
269 			}
270 
271 			q_stats->q_len 	   = qlen(rqp->rq_q);
272 			q_stats->q_limit   = qlimit(rqp->rq_q);
273 
274 			rp = rqp->rq_blue;
275 			q_stats->q_pmark = rp->blue_pmark;
276 			q_stats->xmit_packets  = rp->blue_stats.xmit_packets;
277 			q_stats->xmit_bytes    = rp->blue_stats.xmit_bytes;
278 			q_stats->drop_packets  = rp->blue_stats.drop_packets;
279 			q_stats->drop_bytes    = rp->blue_stats.drop_bytes;
280 			q_stats->drop_forced   = rp->blue_stats.drop_forced;
281 			q_stats->drop_unforced = rp->blue_stats.drop_unforced;
282 			q_stats->marked_packets = rp->blue_stats.marked_packets;
283 
284 		} while (/*CONSTCOND*/ 0);
285 		break;
286 
287 	case BLUE_CONFIG:
288 		do {
289 			struct blue_conf *fc;
290 			int limit;
291 
292 			fc = (struct blue_conf *)addr;
293 			if ((rqp = altq_lookup(fc->iface.blue_ifname,
294 					       ALTQT_BLUE)) == NULL) {
295 				error = EBADF;
296 				break;
297 			}
298 			limit = fc->blue_limit;
299 			qlimit(rqp->rq_q) = limit;
300 			fc->blue_limit = limit;	/* write back the new value */
301 			if (fc->blue_pkttime > 0)
302 				rqp->rq_blue->blue_pkttime = fc->blue_pkttime;
303 			if (fc->blue_max_pmark > 0)
304 				rqp->rq_blue->blue_max_pmark = fc->blue_max_pmark;
305 			if (fc->blue_hold_time > 0)
306 				rqp->rq_blue->blue_hold_time = fc->blue_hold_time;
307 			rqp->rq_blue->blue_flags = fc->blue_flags;
308 
309 			blue_init(rqp->rq_blue, rqp->rq_blue->blue_flags,
310 				  rqp->rq_blue->blue_pkttime,
311 				  rqp->rq_blue->blue_max_pmark,
312 				  rqp->rq_blue->blue_hold_time);
313 		} while (/*CONSTCOND*/ 0);
314 		break;
315 
316 	default:
317 		error = EINVAL;
318 		break;
319 	}
320 	return error;
321 }
322 
323 static int
324 blue_detach(blue_queue_t *rqp)
325 {
326 	blue_queue_t *tmp;
327 	int error = 0;
328 
329 	if (ALTQ_IS_ENABLED(rqp->rq_ifq))
330 		altq_disable(rqp->rq_ifq);
331 
332 	if ((error = altq_detach(rqp->rq_ifq)))
333 		return (error);
334 
335 	if (blue_list == rqp)
336 		blue_list = rqp->rq_next;
337 	else {
338 		for (tmp = blue_list; tmp != NULL; tmp = tmp->rq_next)
339 			if (tmp->rq_next == rqp) {
340 				tmp->rq_next = rqp->rq_next;
341 				break;
342 			}
343 		if (tmp == NULL)
344 			printf("blue_detach: no state found in blue_list!\n");
345 	}
346 
347 	free(rqp->rq_q, M_DEVBUF);
348 	free(rqp->rq_blue, M_DEVBUF);
349 	free(rqp, M_DEVBUF);
350 	return error;
351 }
352 
353 /*
354  * blue support routines
355  */
356 
357 int
358 blue_init(blue_t *rp, int flags, int pkttime, int blue_max_pmark,
359     int blue_hold_time)
360 {
361 	int npkts_per_sec;
362 
363 	rp->blue_idle = 1;
364 	rp->blue_flags = flags;
365 	rp->blue_pkttime = pkttime;
366 	rp->blue_max_pmark = blue_max_pmark;
367 	rp->blue_hold_time = blue_hold_time;
368 	if (pkttime == 0)
369 		rp->blue_pkttime = 1;
370 
371 	/* when the link is very slow, adjust blue parameters */
372 	npkts_per_sec = 1000000 / rp->blue_pkttime;
373 	if (npkts_per_sec < 50) {
374 	}
375 	else if (npkts_per_sec < 300) {
376 	}
377 
378 	microtime(&rp->blue_last);
379 	return 0;
380 }
381 
382 /*
383  * enqueue routine:
384  *
385  *	returns: 0 when successfully queued.
386  *		 ENOBUFS when drop occurs.
387  */
388 static int
389 blue_enqueue(struct ifaltq *ifq, struct mbuf *m)
390 {
391 	struct altq_pktattr pktattr;
392 	blue_queue_t *rqp = (blue_queue_t *)ifq->altq_disc;
393 	int error = 0;
394 
395 	pktattr.pattr_class = m->m_pkthdr.pattr_class;
396 	pktattr.pattr_af = m->m_pkthdr.pattr_af;
397 	pktattr.pattr_hdr = m->m_pkthdr.pattr_hdr;
398 
399 	if (blue_addq(rqp->rq_blue, rqp->rq_q, m, &pktattr) == 0)
400 		ifq->ifq_len++;
401 	else
402 		error = ENOBUFS;
403 	return error;
404 }
405 
406 #define	DTYPE_NODROP	0	/* no drop */
407 #define	DTYPE_FORCED	1	/* a "forced" drop */
408 #define	DTYPE_EARLY	2	/* an "unforced" (early) drop */
409 
410 int
411 blue_addq(blue_t *rp, class_queue_t *q, struct mbuf *m,
412     struct altq_pktattr *pktattr)
413 {
414 	int droptype;
415 
416 	/*
417 	 * if we were idle, this is an enqueue onto an empty queue
418 	 * and we should decrement marking probability
419 	 *
420 	 */
421 	if (rp->blue_idle) {
422 		struct timeval now;
423 		int t;
424 		rp->blue_idle = 0;
425 		microtime(&now);
426 		t = (now.tv_sec - rp->blue_last.tv_sec);
427 		if ( t > 1) {
428 			rp->blue_pmark = 1;
429 			microtime(&rp->blue_last);
430 		} else {
431 			t = t * 1000000 + (now.tv_usec - rp->blue_last.tv_usec);
432 			if (t > rp->blue_hold_time) {
433 				rp->blue_pmark--;
434 				if (rp->blue_pmark < 0) rp->blue_pmark = 0;
435 				microtime(&rp->blue_last);
436 			}
437 		}
438 	}
439 
440 	/* see if we drop early */
441 	droptype = DTYPE_NODROP;
442 	if (drop_early(rp) && qlen(q) > 1) {
443 		/* mark or drop by blue */
444 		if ((rp->blue_flags & BLUEF_ECN) &&
445 		    mark_ecn(m, pktattr, rp->blue_flags)) {
446 			/* successfully marked.  do not drop. */
447 #ifdef BLUE_STATS
448 			rp->blue_stats.marked_packets++;
449 #endif
450 		} else {
451 			/* unforced drop by blue */
452 			droptype = DTYPE_EARLY;
453 		}
454 	}
455 
456 	/*
457 	 * if the queue length hits the hard limit, it's a forced drop.
458 	 */
459 	if (droptype == DTYPE_NODROP && qlen(q) >= qlimit(q))
460 		droptype = DTYPE_FORCED;
461 
462 	/* if successful or forced drop, enqueue this packet. */
463 	if (droptype != DTYPE_EARLY)
464 		_addq(q, m);
465 
466 	if (droptype != DTYPE_NODROP) {
467 		if (droptype == DTYPE_EARLY) {
468 			/* drop the incoming packet */
469 #ifdef BLUE_STATS
470 			rp->blue_stats.drop_unforced++;
471 #endif
472 		} else {
473 			struct timeval now;
474 			int t;
475 			/* forced drop, select a victim packet in the queue. */
476 			m = _getq_random(q);
477 			microtime(&now);
478 			t = (now.tv_sec - rp->blue_last.tv_sec);
479 			t = t * 1000000 + (now.tv_usec - rp->blue_last.tv_usec);
480 			if (t > rp->blue_hold_time) {
481 				rp->blue_pmark += rp->blue_max_pmark >> 3;
482 				if (rp->blue_pmark > rp->blue_max_pmark)
483 					rp->blue_pmark = rp->blue_max_pmark;
484 				microtime(&rp->blue_last);
485 			}
486 #ifdef BLUE_STATS
487 			rp->blue_stats.drop_forced++;
488 #endif
489 		}
490 #ifdef BLUE_STATS
491 		rp->blue_stats.drop_packets++;
492 		rp->blue_stats.drop_bytes += m->m_pkthdr.len;
493 #endif
494 		m_freem(m);
495 		return -1;
496 	}
497 	/* successfully queued */
498 	return 0;
499 }
500 
501 /*
502  * early-drop probability is kept in blue_pmark
503  *
504  */
505 static int
506 drop_early(blue_t *rp)
507 {
508 	if ((cprng_fast32() % rp->blue_max_pmark) < rp->blue_pmark) {
509 		/* drop or mark */
510 		return 1;
511 	}
512 	/* no drop/mark */
513 	return (0);
514 }
515 
516 /*
517  * try to mark CE bit to the packet.
518  *    returns 1 if successfully marked, 0 otherwise.
519  */
520 static int
521 mark_ecn(struct mbuf *m, struct altq_pktattr *pktattr, int flags)
522 {
523 	struct mbuf *m0;
524 
525 	if (pktattr == NULL ||
526 	    (pktattr->pattr_af != AF_INET && pktattr->pattr_af != AF_INET6))
527 		return 0;
528 
529 	/* verify that pattr_hdr is within the mbuf data */
530 	for (m0 = m; m0 != NULL; m0 = m0->m_next)
531 		if (((char *)pktattr->pattr_hdr >= m0->m_data) &&
532 		    ((char *)pktattr->pattr_hdr < m0->m_data + m0->m_len))
533 			break;
534 	if (m0 == NULL) {
535 		/* ick, pattr_hdr is stale */
536 		pktattr->pattr_af = AF_UNSPEC;
537 		return 0;
538 	}
539 
540 	switch (pktattr->pattr_af) {
541 	case AF_INET:
542 		if (flags & BLUEF_ECN4) {
543 			struct ip *ip = (struct ip *)pktattr->pattr_hdr;
544 			u_int8_t otos;
545 			int sum;
546 
547 			if (ip->ip_v != 4)
548 				return (0);	/* version mismatch! */
549 			if ((ip->ip_tos & IPTOS_ECN_MASK) == IPTOS_ECN_NOTECT)
550 				return (0);	/* not-ECT */
551 			if ((ip->ip_tos & IPTOS_ECN_MASK) == IPTOS_ECN_CE)
552 				return (1);	/* already marked */
553 
554 			/*
555 			 * ecn-capable but not marked,
556 			 * mark CE and update checksum
557 			 */
558 			otos = ip->ip_tos;
559 			ip->ip_tos |= IPTOS_ECN_CE;
560 			/*
561 			 * update checksum (from RFC1624)
562 			 *	   HC' = ~(~HC + ~m + m')
563 			 */
564 			sum = ~ntohs(ip->ip_sum) & 0xffff;
565 			sum += (~otos & 0xffff) + ip->ip_tos;
566 			sum = (sum >> 16) + (sum & 0xffff);
567 			sum += (sum >> 16);  /* add carry */
568 			ip->ip_sum = htons(~sum & 0xffff);
569 			return 1;
570 		}
571 		break;
572 #ifdef INET6
573 	case AF_INET6:
574 		if (flags & BLUEF_ECN6) {
575 			struct ip6_hdr *ip6 = (struct ip6_hdr *)pktattr->pattr_hdr;
576 			u_int32_t flowlabel;
577 
578 			flowlabel = ntohl(ip6->ip6_flow);
579 			if ((flowlabel >> 28) != 6)
580 				return (0);	/* version mismatch! */
581 			if ((flowlabel & (IPTOS_ECN_MASK << 20)) ==
582 			    (IPTOS_ECN_NOTECT << 20))
583 				return (0);	/* not-ECT */
584 			if ((flowlabel & (IPTOS_ECN_MASK << 20)) ==
585 			    (IPTOS_ECN_CE << 20))
586 				return (1);	/* already marked */
587 			/*
588 			 * ecn-capable but not marked,  mark CE
589 			 */
590 			flowlabel |= (IPTOS_ECN_CE << 20);
591 			ip6->ip6_flow = htonl(flowlabel);
592 			return (1);
593 		}
594 		break;
595 #endif  /* INET6 */
596 	}
597 
598 	/* not marked */
599 	return 0;
600 }
601 
602 /*
603  * dequeue routine:
604  *	must be called in splnet.
605  *
606  *	returns: mbuf dequeued.
607  *		 NULL when no packet is available in the queue.
608  */
609 
610 static struct mbuf *
611 blue_dequeue(struct ifaltq * ifq, int op)
612 {
613 	blue_queue_t *rqp = (blue_queue_t *)ifq->altq_disc;
614 	struct mbuf *m = NULL;
615 
616 	if (op == ALTDQ_POLL)
617 		return (qhead(rqp->rq_q));
618 
619 	m = blue_getq(rqp->rq_blue, rqp->rq_q);
620 	if (m != NULL)
621 		ifq->ifq_len--;
622 	return m;
623 }
624 
625 struct mbuf *
626 blue_getq(blue_t *rp, class_queue_t *q)
627 {
628 	struct mbuf *m;
629 
630 	if ((m = _getq(q)) == NULL) {
631 		if (rp->blue_idle == 0) {
632 			rp->blue_idle = 1;
633 			microtime(&rp->blue_last);
634 		}
635 		return NULL;
636 	}
637 
638 	rp->blue_idle = 0;
639 #ifdef BLUE_STATS
640 	rp->blue_stats.xmit_packets++;
641 	rp->blue_stats.xmit_bytes += m->m_pkthdr.len;
642 #endif
643 	return m;
644 }
645 
646 static int
647 blue_request(struct ifaltq *ifq, int req, void *arg)
648 {
649 	blue_queue_t *rqp = (blue_queue_t *)ifq->altq_disc;
650 
651 	switch (req) {
652 	case ALTRQ_PURGE:
653 		_flushq(rqp->rq_q);
654 		if (ALTQ_IS_ENABLED(ifq))
655 			ifq->ifq_len = 0;
656 		break;
657 	}
658 	return 0;
659 }
660 
661 
662 #ifdef KLD_MODULE
663 
664 static struct altqsw blue_sw =
665 	{"blue", blueopen, blueclose, blueioctl};
666 
667 ALTQ_MODULE(altq_blue, ALTQT_BLUE, &blue_sw);
668 
669 #endif /* KLD_MODULE */
670 
671 #endif /* ALTQ3_COMPAT */
672 #endif /* ALTQ_BLUE */
673