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altq_rio.c revision 1.7
      1 /*	$NetBSD: altq_rio.c,v 1.7 2005/02/26 23:04:16 perry Exp $	*/
      2 /*	$KAME: altq_rio.c,v 1.8 2000/12/14 08:12:46 thorpej Exp $	*/
      3 
      4 /*
      5  * Copyright (C) 1998-2000
      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  * Copyright (c) 1990-1994 Regents of the University of California.
     31  * All rights reserved.
     32  *
     33  * Redistribution and use in source and binary forms, with or without
     34  * modification, are permitted provided that the following conditions
     35  * are met:
     36  * 1. Redistributions of source code must retain the above copyright
     37  *    notice, this list of conditions and the following disclaimer.
     38  * 2. Redistributions in binary form must reproduce the above copyright
     39  *    notice, this list of conditions and the following disclaimer in the
     40  *    documentation and/or other materials provided with the distribution.
     41  * 3. All advertising materials mentioning features or use of this software
     42  *    must display the following acknowledgement:
     43  *	This product includes software developed by the Computer Systems
     44  *	Engineering Group at Lawrence Berkeley Laboratory.
     45  * 4. Neither the name of the University nor of the Laboratory may be used
     46  *    to endorse or promote products derived from this software without
     47  *    specific prior written permission.
     48  *
     49  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     50  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     51  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     52  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     53  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     54  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     55  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     56  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     57  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     58  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     59  * SUCH DAMAGE.
     60  */
     61 
     62 #include <sys/cdefs.h>
     63 __KERNEL_RCSID(0, "$NetBSD: altq_rio.c,v 1.7 2005/02/26 23:04:16 perry Exp $");
     64 
     65 #if defined(__FreeBSD__) || defined(__NetBSD__)
     66 #include "opt_altq.h"
     67 #if (__FreeBSD__ != 2)
     68 #include "opt_inet.h"
     69 #ifdef __FreeBSD__
     70 #include "opt_inet6.h"
     71 #endif
     72 #endif
     73 #endif /* __FreeBSD__ || __NetBSD__ */
     74 #ifdef ALTQ_RIO	/* rio is enabled by ALTQ_RIO option in opt_altq.h */
     75 
     76 #include <sys/param.h>
     77 #include <sys/malloc.h>
     78 #include <sys/mbuf.h>
     79 #include <sys/socket.h>
     80 #include <sys/sockio.h>
     81 #include <sys/systm.h>
     82 #include <sys/proc.h>
     83 #include <sys/errno.h>
     84 #include <sys/kernel.h>
     85 
     86 #include <net/if.h>
     87 #include <net/if_types.h>
     88 
     89 #include <netinet/in.h>
     90 #include <netinet/in_systm.h>
     91 #include <netinet/ip.h>
     92 #ifdef INET6
     93 #include <netinet/ip6.h>
     94 #endif
     95 
     96 #include <altq/altq.h>
     97 #include <altq/altq_conf.h>
     98 #include <altq/altq_cdnr.h>
     99 #include <altq/altq_red.h>
    100 #include <altq/altq_rio.h>
    101 
    102 /*
    103  * RIO: RED with IN/OUT bit
    104  *   described in
    105  *	"Explicit Allocation of Best Effort Packet Delivery Service"
    106  *	David D. Clark and Wenjia Fang, MIT Lab for Computer Science
    107  *	http://diffserv.lcs.mit.edu/Papers/exp-alloc-ddc-wf.{ps,pdf}
    108  *
    109  * this implementation is extended to support more than 2 drop precedence
    110  * values as described in RFC2597 (Assured Forwarding PHB Group).
    111  *
    112  */
    113 /*
    114  * AF DS (differentiated service) codepoints.
    115  * (classes can be mapped to CBQ or H-FSC classes.)
    116  *
    117  *      0   1   2   3   4   5   6   7
    118  *    +---+---+---+---+---+---+---+---+
    119  *    |   CLASS   |DropPre| 0 |  CU   |
    120  *    +---+---+---+---+---+---+---+---+
    121  *
    122  *    class 1: 001
    123  *    class 2: 010
    124  *    class 3: 011
    125  *    class 4: 100
    126  *
    127  *    low drop prec:    01
    128  *    medium drop prec: 10
    129  *    high drop prec:   01
    130  */
    131 
    132 /* normal red parameters */
    133 #define	W_WEIGHT	512	/* inverse of weight of EWMA (511/512) */
    134 				/* q_weight = 0.00195 */
    135 
    136 /* red parameters for a slow link */
    137 #define	W_WEIGHT_1	128	/* inverse of weight of EWMA (127/128) */
    138 				/* q_weight = 0.0078125 */
    139 
    140 /* red parameters for a very slow link (e.g., dialup) */
    141 #define	W_WEIGHT_2	64	/* inverse of weight of EWMA (63/64) */
    142 				/* q_weight = 0.015625 */
    143 
    144 /* fixed-point uses 12-bit decimal places */
    145 #define	FP_SHIFT	12	/* fixed-point shift */
    146 
    147 /* red parameters for drop probability */
    148 #define	INV_P_MAX	10	/* inverse of max drop probability */
    149 #define	TH_MIN		 5	/* min threshold */
    150 #define	TH_MAX		15	/* max threshold */
    151 
    152 #define	RIO_LIMIT	60	/* default max queue length */
    153 
    154 #define	TV_DELTA(a, b, delta) {					\
    155 	register int	xxs;					\
    156 								\
    157 	delta = (a)->tv_usec - (b)->tv_usec; 			\
    158 	if ((xxs = (a)->tv_sec - (b)->tv_sec) != 0) { 		\
    159 		if (xxs < 0) { 					\
    160 			printf("rm_class: bogus time values");	\
    161 			delta = 60000000;			\
    162 		} else if (xxs > 4)  {				\
    163 			if (xxs > 60)				\
    164 				delta = 60000000;		\
    165 			else					\
    166 				delta += xxs * 1000000;		\
    167 		} else while (xxs > 0) {			\
    168 			delta += 1000000;			\
    169 			xxs--;					\
    170 		}						\
    171 	}							\
    172 }
    173 
    174 /* rio_list keeps all rio_queue_t's allocated. */
    175 static rio_queue_t *rio_list = NULL;
    176 /* default rio parameter values */
    177 static struct redparams default_rio_params[RIO_NDROPPREC] = {
    178   /* th_min,		 th_max,     inv_pmax */
    179   { TH_MAX * 2 + TH_MIN, TH_MAX * 3, INV_P_MAX }, /* low drop precedence */
    180   { TH_MAX + TH_MIN,	 TH_MAX * 2, INV_P_MAX }, /* medium drop precedence */
    181   { TH_MIN,		 TH_MAX,     INV_P_MAX }  /* high drop precedence */
    182 };
    183 
    184 /* internal function prototypes */
    185 static int rio_enqueue __P((struct ifaltq *, struct mbuf *,
    186 			    struct altq_pktattr *));
    187 static struct mbuf *rio_dequeue __P((struct ifaltq *, int));
    188 static int rio_request __P((struct ifaltq *, int, void *));
    189 static int rio_detach __P((rio_queue_t *));
    190 static int dscp2index __P((u_int8_t));
    191 
    192 /*
    193  * rio device interface
    194  */
    195 altqdev_decl(rio);
    196 
    197 int
    198 rioopen(dev, flag, fmt, p)
    199 	dev_t dev;
    200 	int flag, fmt;
    201 	struct proc *p;
    202 {
    203 	/* everything will be done when the queueing scheme is attached. */
    204 	return 0;
    205 }
    206 
    207 int
    208 rioclose(dev, flag, fmt, p)
    209 	dev_t dev;
    210 	int flag, fmt;
    211 	struct proc *p;
    212 {
    213 	rio_queue_t *rqp;
    214 	int err, error = 0;
    215 
    216 	while ((rqp = rio_list) != NULL) {
    217 		/* destroy all */
    218 		err = rio_detach(rqp);
    219 		if (err != 0 && error == 0)
    220 			error = err;
    221 	}
    222 
    223 	return error;
    224 }
    225 
    226 int
    227 rioioctl(dev, cmd, addr, flag, p)
    228 	dev_t dev;
    229 	ioctlcmd_t cmd;
    230 	caddr_t addr;
    231 	int flag;
    232 	struct proc *p;
    233 {
    234 	rio_queue_t *rqp;
    235 	struct rio_interface *ifacep;
    236 	struct ifnet *ifp;
    237 	int	error = 0;
    238 
    239 	/* check super-user privilege */
    240 	switch (cmd) {
    241 	case RIO_GETSTATS:
    242 		break;
    243 	default:
    244 #if (__FreeBSD_version > 400000)
    245 		if ((error = suser(p)) != 0)
    246 			return (error);
    247 #else
    248 		if ((error = suser(p->p_ucred, &p->p_acflag)) != 0)
    249 			return (error);
    250 #endif
    251 		break;
    252 	}
    253 
    254 	switch (cmd) {
    255 
    256 	case RIO_ENABLE:
    257 		ifacep = (struct rio_interface *)addr;
    258 		if ((rqp = altq_lookup(ifacep->rio_ifname, ALTQT_RIO)) == NULL) {
    259 			error = EBADF;
    260 			break;
    261 		}
    262 		error = altq_enable(rqp->rq_ifq);
    263 		break;
    264 
    265 	case RIO_DISABLE:
    266 		ifacep = (struct rio_interface *)addr;
    267 		if ((rqp = altq_lookup(ifacep->rio_ifname, ALTQT_RIO)) == NULL) {
    268 			error = EBADF;
    269 			break;
    270 		}
    271 		error = altq_disable(rqp->rq_ifq);
    272 		break;
    273 
    274 	case RIO_IF_ATTACH:
    275 		ifp = ifunit(((struct rio_interface *)addr)->rio_ifname);
    276 		if (ifp == NULL) {
    277 			error = ENXIO;
    278 			break;
    279 		}
    280 
    281 		/* allocate and initialize rio_queue_t */
    282 		MALLOC(rqp, rio_queue_t *, sizeof(rio_queue_t), M_DEVBUF, M_WAITOK);
    283 		if (rqp == NULL) {
    284 			error = ENOMEM;
    285 			break;
    286 		}
    287 		(void)memset(rqp, 0, sizeof(rio_queue_t));
    288 
    289 		MALLOC(rqp->rq_q, class_queue_t *, sizeof(class_queue_t),
    290 		       M_DEVBUF, M_WAITOK);
    291 		if (rqp->rq_q == NULL) {
    292 			FREE(rqp, M_DEVBUF);
    293 			error = ENOMEM;
    294 			break;
    295 		}
    296 		(void)memset(rqp->rq_q, 0, sizeof(class_queue_t));
    297 
    298 		rqp->rq_rio = rio_alloc(0, NULL, 0, 0);
    299 		if (rqp->rq_rio == NULL) {
    300 			FREE(rqp->rq_q, M_DEVBUF);
    301 			FREE(rqp, M_DEVBUF);
    302 			error = ENOMEM;
    303 			break;
    304 		}
    305 
    306 		rqp->rq_ifq = &ifp->if_snd;
    307 		qtail(rqp->rq_q) = NULL;
    308 		qlen(rqp->rq_q) = 0;
    309 		qlimit(rqp->rq_q) = RIO_LIMIT;
    310 		qtype(rqp->rq_q) = Q_RIO;
    311 
    312 		/*
    313 		 * set RIO to this ifnet structure.
    314 		 */
    315 		error = altq_attach(rqp->rq_ifq, ALTQT_RIO, rqp,
    316 				    rio_enqueue, rio_dequeue, rio_request,
    317 				    NULL, NULL);
    318 		if (error) {
    319 			rio_destroy(rqp->rq_rio);
    320 			FREE(rqp->rq_q, M_DEVBUF);
    321 			FREE(rqp, M_DEVBUF);
    322 			break;
    323 		}
    324 
    325 		/* add this state to the rio list */
    326 		rqp->rq_next = rio_list;
    327 		rio_list = rqp;
    328 		break;
    329 
    330 	case RIO_IF_DETACH:
    331 		ifacep = (struct rio_interface *)addr;
    332 		if ((rqp = altq_lookup(ifacep->rio_ifname, ALTQT_RIO)) == NULL) {
    333 			error = EBADF;
    334 			break;
    335 		}
    336 		error = rio_detach(rqp);
    337 		break;
    338 
    339 	case RIO_GETSTATS:
    340 		do {
    341 			struct rio_stats *q_stats;
    342 			rio_t *rp;
    343 			int i;
    344 
    345 			q_stats = (struct rio_stats *)addr;
    346 			if ((rqp = altq_lookup(q_stats->iface.rio_ifname,
    347 					       ALTQT_RIO)) == NULL) {
    348 				error = EBADF;
    349 				break;
    350 			}
    351 
    352 			rp = rqp->rq_rio;
    353 
    354 			q_stats->q_limit = qlimit(rqp->rq_q);
    355 			q_stats->weight	= rp->rio_weight;
    356 			q_stats->flags = rp->rio_flags;
    357 
    358 			for (i = 0; i < RIO_NDROPPREC; i++) {
    359 				q_stats->q_len[i] = rp->rio_precstate[i].qlen;
    360 				(void)memcpy(&q_stats->q_stats[i],
    361 				    &rp->q_stats[i], sizeof(struct redstats));
    362 				q_stats->q_stats[i].q_avg =
    363 				    rp->rio_precstate[i].avg >> rp->rio_wshift;
    364 
    365 				q_stats->q_params[i].inv_pmax
    366 					= rp->rio_precstate[i].inv_pmax;
    367 				q_stats->q_params[i].th_min
    368 					= rp->rio_precstate[i].th_min;
    369 				q_stats->q_params[i].th_max
    370 					= rp->rio_precstate[i].th_max;
    371 			}
    372 		} while (0);
    373 		break;
    374 
    375 	case RIO_CONFIG:
    376 		do {
    377 			struct rio_conf *fc;
    378 			rio_t	*new;
    379 			int s, limit, i;
    380 
    381 			fc = (struct rio_conf *)addr;
    382 			if ((rqp = altq_lookup(fc->iface.rio_ifname,
    383 					       ALTQT_RIO)) == NULL) {
    384 				error = EBADF;
    385 				break;
    386 			}
    387 
    388 			new = rio_alloc(fc->rio_weight, &fc->q_params[0],
    389 					fc->rio_flags, fc->rio_pkttime);
    390 			if (new == NULL) {
    391 				error = ENOMEM;
    392 				break;
    393 			}
    394 
    395 			s = splnet();
    396 			_flushq(rqp->rq_q);
    397 			limit = fc->rio_limit;
    398 			if (limit < fc->q_params[RIO_NDROPPREC-1].th_max)
    399 				limit = fc->q_params[RIO_NDROPPREC-1].th_max;
    400 			qlimit(rqp->rq_q) = limit;
    401 
    402 			rio_destroy(rqp->rq_rio);
    403 			rqp->rq_rio = new;
    404 
    405 			splx(s);
    406 
    407 			/* write back new values */
    408 			fc->rio_limit = limit;
    409 			for (i = 0; i < RIO_NDROPPREC; i++) {
    410 				fc->q_params[i].inv_pmax =
    411 					rqp->rq_rio->rio_precstate[i].inv_pmax;
    412 				fc->q_params[i].th_min =
    413 					rqp->rq_rio->rio_precstate[i].th_min;
    414 				fc->q_params[i].th_max =
    415 					rqp->rq_rio->rio_precstate[i].th_max;
    416 			}
    417 		} while (0);
    418 		break;
    419 
    420 	case RIO_SETDEFAULTS:
    421 		do {
    422 			struct redparams *rp;
    423 			int i;
    424 
    425 			rp = (struct redparams *)addr;
    426 			for (i = 0; i < RIO_NDROPPREC; i++)
    427 				default_rio_params[i] = rp[i];
    428 		} while (0);
    429 		break;
    430 
    431 	default:
    432 		error = EINVAL;
    433 		break;
    434 	}
    435 
    436 	return error;
    437 }
    438 
    439 static int
    440 rio_detach(rqp)
    441 	rio_queue_t *rqp;
    442 {
    443 	rio_queue_t *tmp;
    444 	int error = 0;
    445 
    446 	if (ALTQ_IS_ENABLED(rqp->rq_ifq))
    447 		altq_disable(rqp->rq_ifq);
    448 
    449 	if ((error = altq_detach(rqp->rq_ifq)))
    450 		return (error);
    451 
    452 	if (rio_list == rqp)
    453 		rio_list = rqp->rq_next;
    454 	else {
    455 		for (tmp = rio_list; tmp != NULL; tmp = tmp->rq_next)
    456 			if (tmp->rq_next == rqp) {
    457 				tmp->rq_next = rqp->rq_next;
    458 				break;
    459 			}
    460 		if (tmp == NULL)
    461 			printf("rio_detach: no state found in rio_list!\n");
    462 	}
    463 
    464 	rio_destroy(rqp->rq_rio);
    465 	FREE(rqp->rq_q, M_DEVBUF);
    466 	FREE(rqp, M_DEVBUF);
    467 	return (error);
    468 }
    469 
    470 /*
    471  * rio support routines
    472  */
    473 static int
    474 rio_request(ifq, req, arg)
    475 	struct ifaltq *ifq;
    476 	int req;
    477 	void *arg;
    478 {
    479 	rio_queue_t *rqp = (rio_queue_t *)ifq->altq_disc;
    480 
    481 	switch (req) {
    482 	case ALTRQ_PURGE:
    483 		_flushq(rqp->rq_q);
    484 		if (ALTQ_IS_ENABLED(ifq))
    485 			ifq->ifq_len = 0;
    486 		break;
    487 	}
    488 	return (0);
    489 }
    490 
    491 
    492 rio_t *
    493 rio_alloc(weight, params, flags, pkttime)
    494 	int	weight;
    495 	struct redparams *params;
    496 	int	flags, pkttime;
    497 {
    498 	rio_t 	*rp;
    499 	int	w, i;
    500 	int	npkts_per_sec;
    501 
    502 	MALLOC(rp, rio_t *, sizeof(rio_t), M_DEVBUF, M_WAITOK);
    503 	if (rp == NULL)
    504 		return (NULL);
    505 	(void)memset(rp, 0, sizeof(rio_t));
    506 
    507 	rp->rio_flags = flags;
    508 	if (pkttime == 0)
    509 		/* default packet time: 1000 bytes / 10Mbps * 8 * 1000000 */
    510 		rp->rio_pkttime = 800;
    511 	else
    512 		rp->rio_pkttime = pkttime;
    513 
    514 	if (weight != 0)
    515 		rp->rio_weight = weight;
    516 	else {
    517 		/* use derfault */
    518 		rp->rio_weight = W_WEIGHT;
    519 
    520 		/* when the link is very slow, adjust red parameters */
    521 		npkts_per_sec = 1000000 / rp->rio_pkttime;
    522 		if (npkts_per_sec < 50) {
    523 			/* up to about 400Kbps */
    524 			rp->rio_weight = W_WEIGHT_2;
    525 		} else if (npkts_per_sec < 300) {
    526 			/* up to about 2.4Mbps */
    527 			rp->rio_weight = W_WEIGHT_1;
    528 		}
    529 	}
    530 
    531 	/* calculate wshift.  weight must be power of 2 */
    532 	w = rp->rio_weight;
    533 	for (i = 0; w > 1; i++)
    534 		w = w >> 1;
    535 	rp->rio_wshift = i;
    536 	w = 1 << rp->rio_wshift;
    537 	if (w != rp->rio_weight) {
    538 		printf("invalid weight value %d for red! use %d\n",
    539 		       rp->rio_weight, w);
    540 		rp->rio_weight = w;
    541 	}
    542 
    543 	/* allocate weight table */
    544 	rp->rio_wtab = wtab_alloc(rp->rio_weight);
    545 
    546 	for (i = 0; i < RIO_NDROPPREC; i++) {
    547 		struct dropprec_state *prec = &rp->rio_precstate[i];
    548 
    549 		prec->avg = 0;
    550 		prec->idle = 1;
    551 
    552 		if (params == NULL || params[i].inv_pmax == 0)
    553 			prec->inv_pmax = default_rio_params[i].inv_pmax;
    554 		else
    555 			prec->inv_pmax = params[i].inv_pmax;
    556 		if (params == NULL || params[i].th_min == 0)
    557 			prec->th_min = default_rio_params[i].th_min;
    558 		else
    559 			prec->th_min = params[i].th_min;
    560 		if (params == NULL || params[i].th_max == 0)
    561 			prec->th_max = default_rio_params[i].th_max;
    562 		else
    563 			prec->th_max = params[i].th_max;
    564 
    565 		/*
    566 		 * th_min_s and th_max_s are scaled versions of th_min
    567 		 * and th_max to be compared with avg.
    568 		 */
    569 		prec->th_min_s = prec->th_min << (rp->rio_wshift + FP_SHIFT);
    570 		prec->th_max_s = prec->th_max << (rp->rio_wshift + FP_SHIFT);
    571 
    572 		/*
    573 		 * precompute probability denominator
    574 		 *  probd = (2 * (TH_MAX-TH_MIN) / pmax) in fixed-point
    575 		 */
    576 		prec->probd = (2 * (prec->th_max - prec->th_min)
    577 			       * prec->inv_pmax) << FP_SHIFT;
    578 
    579 		microtime(&prec->last);
    580 	}
    581 
    582 	return (rp);
    583 }
    584 
    585 void
    586 rio_destroy(rp)
    587 	rio_t *rp;
    588 {
    589 	wtab_destroy(rp->rio_wtab);
    590 	FREE(rp, M_DEVBUF);
    591 }
    592 
    593 void
    594 rio_getstats(rp, sp)
    595 	rio_t *rp;
    596 	struct redstats *sp;
    597 {
    598 	int i;
    599 
    600 	for (i = 0; i < RIO_NDROPPREC; i++) {
    601 		(void)memcpy(sp, &rp->q_stats[i], sizeof(struct redstats));
    602 		sp->q_avg = rp->rio_precstate[i].avg >> rp->rio_wshift;
    603 		sp++;
    604 	}
    605 }
    606 
    607 /*
    608  * enqueue routine:
    609  *
    610  *	returns: 0 when successfully queued.
    611  *		 ENOBUFS when drop occurs.
    612  */
    613 static int
    614 rio_enqueue(ifq, m, pktattr)
    615 	struct ifaltq *ifq;
    616 	struct mbuf *m;
    617 	struct altq_pktattr *pktattr;
    618 {
    619 	rio_queue_t *rqp = (rio_queue_t *)ifq->altq_disc;
    620 	int error = 0;
    621 
    622 	if (rio_addq(rqp->rq_rio, rqp->rq_q, m, pktattr) == 0)
    623 		ifq->ifq_len++;
    624 	else
    625 		error = ENOBUFS;
    626 	return error;
    627 }
    628 
    629 #if (RIO_NDROPPREC == 3)
    630 /*
    631  * internally, a drop precedence value is converted to an index
    632  * starting from 0.
    633  */
    634 static int
    635 dscp2index(u_int8_t dscp)
    636 {
    637 	int dpindex = dscp & AF_DROPPRECMASK;
    638 
    639 	if (dpindex == 0)
    640 		return (0);
    641 	return ((dpindex >> 3) - 1);
    642 }
    643 #endif
    644 
    645 #if 1
    646 /*
    647  * kludge: when a packet is dequeued, we need to know its drop precedence
    648  * in order to keep the queue length of each drop precedence.
    649  * use m_pkthdr.rcvif to pass this info.
    650  */
    651 #define	RIOM_SET_PRECINDEX(m, idx)	\
    652 	do { (m)->m_pkthdr.rcvif = (struct ifnet *)((long)(idx)); } while (0)
    653 #define	RIOM_GET_PRECINDEX(m)	\
    654 	({ long idx; idx = (long)((m)->m_pkthdr.rcvif); \
    655 	(m)->m_pkthdr.rcvif = NULL; idx; })
    656 #endif
    657 
    658 int
    659 rio_addq(rp, q, m, pktattr)
    660 	rio_t *rp;
    661 	class_queue_t *q;
    662 	struct mbuf *m;
    663 	struct altq_pktattr *pktattr;
    664 {
    665 	int avg, droptype;
    666 	u_int8_t dsfield, odsfield;
    667 	int dpindex, i, n, t;
    668 	struct timeval now;
    669 	struct dropprec_state *prec;
    670 
    671 	dsfield = odsfield = read_dsfield(m, pktattr);
    672 	dpindex = dscp2index(dsfield);
    673 
    674 	/*
    675 	 * update avg of the precedence states whose drop precedence
    676 	 * is larger than or equal to the drop precedence of the packet
    677 	 */
    678 	now.tv_sec = 0;
    679 	for (i = dpindex; i < RIO_NDROPPREC; i++) {
    680 		prec = &rp->rio_precstate[i];
    681 		avg = prec->avg;
    682 		if (prec->idle) {
    683 			prec->idle = 0;
    684 			if (now.tv_sec == 0)
    685 				microtime(&now);
    686 			t = (now.tv_sec - prec->last.tv_sec);
    687 			if (t > 60)
    688 				avg = 0;
    689 			else {
    690 				t = t * 1000000 +
    691 					(now.tv_usec - prec->last.tv_usec);
    692 				n = t / rp->rio_pkttime;
    693 				/* calculate (avg = (1 - Wq)^n * avg) */
    694 				if (n > 0)
    695 					avg = (avg >> FP_SHIFT) *
    696 						pow_w(rp->rio_wtab, n);
    697 			}
    698 		}
    699 
    700 		/* run estimator. (avg is scaled by WEIGHT in fixed-point) */
    701 		avg += (prec->qlen << FP_SHIFT) - (avg >> rp->rio_wshift);
    702 		prec->avg = avg;		/* save the new value */
    703 		/*
    704 		 * count keeps a tally of arriving traffic that has not
    705 		 * been dropped.
    706 		 */
    707 		prec->count++;
    708 	}
    709 
    710 	prec = &rp->rio_precstate[dpindex];
    711 	avg = prec->avg;
    712 
    713 	/* see if we drop early */
    714 	droptype = DTYPE_NODROP;
    715 	if (avg >= prec->th_min_s && prec->qlen > 1) {
    716 		if (avg >= prec->th_max_s) {
    717 			/* avg >= th_max: forced drop */
    718 			droptype = DTYPE_FORCED;
    719 		} else if (prec->old == 0) {
    720 			/* first exceeds th_min */
    721 			prec->count = 1;
    722 			prec->old = 1;
    723 		} else if (drop_early((avg - prec->th_min_s) >> rp->rio_wshift,
    724 				      prec->probd, prec->count)) {
    725 			/* unforced drop by red */
    726 			droptype = DTYPE_EARLY;
    727 		}
    728 	} else {
    729 		/* avg < th_min */
    730 		prec->old = 0;
    731 	}
    732 
    733 	/*
    734 	 * if the queue length hits the hard limit, it's a forced drop.
    735 	 */
    736 	if (droptype == DTYPE_NODROP && qlen(q) >= qlimit(q))
    737 		droptype = DTYPE_FORCED;
    738 
    739 	if (droptype != DTYPE_NODROP) {
    740 		/* always drop incoming packet (as opposed to randomdrop) */
    741 		for (i = dpindex; i < RIO_NDROPPREC; i++)
    742 			rp->rio_precstate[i].count = 0;
    743 #ifdef RIO_STATS
    744 		if (droptype == DTYPE_EARLY)
    745 			rp->q_stats[dpindex].drop_unforced++;
    746 		else
    747 			rp->q_stats[dpindex].drop_forced++;
    748 		PKTCNTR_ADD(&rp->q_stats[dpindex].drop_cnt, m_pktlen(m));
    749 #endif
    750 		m_freem(m);
    751 		return (-1);
    752 	}
    753 
    754 	for (i = dpindex; i < RIO_NDROPPREC; i++)
    755 		rp->rio_precstate[i].qlen++;
    756 
    757 	/* save drop precedence index in mbuf hdr */
    758 	RIOM_SET_PRECINDEX(m, dpindex);
    759 
    760 	if (rp->rio_flags & RIOF_CLEARDSCP)
    761 		dsfield &= ~DSCP_MASK;
    762 
    763 	if (dsfield != odsfield)
    764 		write_dsfield(m, pktattr, dsfield);
    765 
    766 	_addq(q, m);
    767 
    768 #ifdef RIO_STATS
    769 	PKTCNTR_ADD(&rp->q_stats[dpindex].xmit_cnt, m_pktlen(m));
    770 #endif
    771 	return (0);
    772 }
    773 
    774 /*
    775  * dequeue routine:
    776  *	must be called in splnet.
    777  *
    778  *	returns: mbuf dequeued.
    779  *		 NULL when no packet is available in the queue.
    780  */
    781 
    782 static struct mbuf *
    783 rio_dequeue(ifq, op)
    784 	struct ifaltq *ifq;
    785 	int op;
    786 {
    787 	rio_queue_t *rqp = (rio_queue_t *)ifq->altq_disc;
    788 	struct mbuf *m = NULL;
    789 
    790 	if (op == ALTDQ_POLL)
    791 		return qhead(rqp->rq_q);
    792 
    793 	m = rio_getq(rqp->rq_rio, rqp->rq_q);
    794 	if (m != NULL)
    795 		ifq->ifq_len--;
    796 	return m;
    797 }
    798 
    799 struct mbuf *
    800 rio_getq(rp, q)
    801 	rio_t *rp;
    802 	class_queue_t *q;
    803 {
    804 	struct mbuf *m;
    805 	int dpindex, i;
    806 
    807 	if ((m = _getq(q)) == NULL)
    808 		return NULL;
    809 
    810 	dpindex = RIOM_GET_PRECINDEX(m);
    811 	for (i = dpindex; i < RIO_NDROPPREC; i++) {
    812 		if (--rp->rio_precstate[i].qlen == 0) {
    813 			if (rp->rio_precstate[i].idle == 0) {
    814 				rp->rio_precstate[i].idle = 1;
    815 				microtime(&rp->rio_precstate[i].last);
    816 			}
    817 		}
    818 	}
    819 	return (m);
    820 }
    821 
    822 #ifdef KLD_MODULE
    823 
    824 static struct altqsw rio_sw =
    825 	{"rio", rioopen, rioclose, rioioctl};
    826 
    827 ALTQ_MODULE(altq_rio, ALTQT_RIO, &rio_sw);
    828 
    829 #endif /* KLD_MODULE */
    830 
    831 #endif /* ALTQ_RIO */
    832