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altq_rio.c revision 1.4
      1 /*	$NetBSD: altq_rio.c,v 1.4 2001/11/12 23:14:22 lukem 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 1.4 2001/11/12 23:14:22 lukem 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 lenght */
    153 #define	RIO_STATS		/* collect statistics */
    154 
    155 #define	TV_DELTA(a, b, delta) {					\
    156 	register int	xxs;					\
    157 								\
    158 	delta = (a)->tv_usec - (b)->tv_usec; 			\
    159 	if ((xxs = (a)->tv_sec - (b)->tv_sec) != 0) { 		\
    160 		if (xxs < 0) { 					\
    161 			printf("rm_class: bogus time values");	\
    162 			delta = 60000000;			\
    163 		} else if (xxs > 4)  {				\
    164 			if (xxs > 60)				\
    165 				delta = 60000000;		\
    166 			else					\
    167 				delta += xxs * 1000000;		\
    168 		} else while (xxs > 0) {			\
    169 			delta += 1000000;			\
    170 			xxs--;					\
    171 		}						\
    172 	}							\
    173 }
    174 
    175 /* rio_list keeps all rio_queue_t's allocated. */
    176 static rio_queue_t *rio_list = NULL;
    177 /* default rio parameter values */
    178 static struct redparams default_rio_params[RIO_NDROPPREC] = {
    179   /* th_min,		 th_max,     inv_pmax */
    180   { TH_MAX * 2 + TH_MIN, TH_MAX * 3, INV_P_MAX }, /* low drop precedence */
    181   { TH_MAX + TH_MIN,	 TH_MAX * 2, INV_P_MAX }, /* medium drop precedence */
    182   { TH_MIN,		 TH_MAX,     INV_P_MAX }  /* high drop precedence */
    183 };
    184 
    185 /* internal function prototypes */
    186 static int rio_enqueue __P((struct ifaltq *, struct mbuf *,
    187 			    struct altq_pktattr *));
    188 static struct mbuf *rio_dequeue __P((struct ifaltq *, int));
    189 static int rio_request __P((struct ifaltq *, int, void *));
    190 static int rio_detach __P((rio_queue_t *));
    191 static int dscp2index __P((u_int8_t));
    192 
    193 /*
    194  * rio device interface
    195  */
    196 altqdev_decl(rio);
    197 
    198 int
    199 rioopen(dev, flag, fmt, p)
    200 	dev_t dev;
    201 	int flag, fmt;
    202 	struct proc *p;
    203 {
    204 	/* everything will be done when the queueing scheme is attached. */
    205 	return 0;
    206 }
    207 
    208 int
    209 rioclose(dev, flag, fmt, p)
    210 	dev_t dev;
    211 	int flag, fmt;
    212 	struct proc *p;
    213 {
    214 	rio_queue_t *rqp;
    215 	int err, error = 0;
    216 
    217 	while ((rqp = rio_list) != NULL) {
    218 		/* destroy all */
    219 		err = rio_detach(rqp);
    220 		if (err != 0 && error == 0)
    221 			error = err;
    222 	}
    223 
    224 	return error;
    225 }
    226 
    227 int
    228 rioioctl(dev, cmd, addr, flag, p)
    229 	dev_t dev;
    230 	ioctlcmd_t cmd;
    231 	caddr_t addr;
    232 	int flag;
    233 	struct proc *p;
    234 {
    235 	rio_queue_t *rqp;
    236 	struct rio_interface *ifacep;
    237 	struct ifnet *ifp;
    238 	int	error = 0;
    239 
    240 	/* check super-user privilege */
    241 	switch (cmd) {
    242 	case RIO_GETSTATS:
    243 		break;
    244 	default:
    245 #if (__FreeBSD_version > 400000)
    246 		if ((error = suser(p)) != 0)
    247 			return (error);
    248 #else
    249 		if ((error = suser(p->p_ucred, &p->p_acflag)) != 0)
    250 			return (error);
    251 #endif
    252 		break;
    253 	}
    254 
    255 	switch (cmd) {
    256 
    257 	case RIO_ENABLE:
    258 		ifacep = (struct rio_interface *)addr;
    259 		if ((rqp = altq_lookup(ifacep->rio_ifname, ALTQT_RIO)) == NULL) {
    260 			error = EBADF;
    261 			break;
    262 		}
    263 		error = altq_enable(rqp->rq_ifq);
    264 		break;
    265 
    266 	case RIO_DISABLE:
    267 		ifacep = (struct rio_interface *)addr;
    268 		if ((rqp = altq_lookup(ifacep->rio_ifname, ALTQT_RIO)) == NULL) {
    269 			error = EBADF;
    270 			break;
    271 		}
    272 		error = altq_disable(rqp->rq_ifq);
    273 		break;
    274 
    275 	case RIO_IF_ATTACH:
    276 		ifp = ifunit(((struct rio_interface *)addr)->rio_ifname);
    277 		if (ifp == NULL) {
    278 			error = ENXIO;
    279 			break;
    280 		}
    281 
    282 		/* allocate and initialize rio_queue_t */
    283 		MALLOC(rqp, rio_queue_t *, sizeof(rio_queue_t), M_DEVBUF, M_WAITOK);
    284 		if (rqp == NULL) {
    285 			error = ENOMEM;
    286 			break;
    287 		}
    288 		bzero(rqp, sizeof(rio_queue_t));
    289 
    290 		MALLOC(rqp->rq_q, class_queue_t *, sizeof(class_queue_t),
    291 		       M_DEVBUF, M_WAITOK);
    292 		if (rqp->rq_q == NULL) {
    293 			FREE(rqp, M_DEVBUF);
    294 			error = ENOMEM;
    295 			break;
    296 		}
    297 		bzero(rqp->rq_q, sizeof(class_queue_t));
    298 
    299 		rqp->rq_rio = rio_alloc(0, NULL, 0, 0);
    300 		if (rqp->rq_rio == NULL) {
    301 			FREE(rqp->rq_q, M_DEVBUF);
    302 			FREE(rqp, M_DEVBUF);
    303 			error = ENOMEM;
    304 			break;
    305 		}
    306 
    307 		rqp->rq_ifq = &ifp->if_snd;
    308 		qtail(rqp->rq_q) = NULL;
    309 		qlen(rqp->rq_q) = 0;
    310 		qlimit(rqp->rq_q) = RIO_LIMIT;
    311 		qtype(rqp->rq_q) = Q_RIO;
    312 
    313 		/*
    314 		 * set RIO to this ifnet structure.
    315 		 */
    316 		error = altq_attach(rqp->rq_ifq, ALTQT_RIO, rqp,
    317 				    rio_enqueue, rio_dequeue, rio_request,
    318 				    NULL, NULL);
    319 		if (error) {
    320 			rio_destroy(rqp->rq_rio);
    321 			FREE(rqp->rq_q, M_DEVBUF);
    322 			FREE(rqp, M_DEVBUF);
    323 			break;
    324 		}
    325 
    326 		/* add this state to the rio list */
    327 		rqp->rq_next = rio_list;
    328 		rio_list = rqp;
    329 		break;
    330 
    331 	case RIO_IF_DETACH:
    332 		ifacep = (struct rio_interface *)addr;
    333 		if ((rqp = altq_lookup(ifacep->rio_ifname, ALTQT_RIO)) == NULL) {
    334 			error = EBADF;
    335 			break;
    336 		}
    337 		error = rio_detach(rqp);
    338 		break;
    339 
    340 	case RIO_GETSTATS:
    341 		do {
    342 			struct rio_stats *q_stats;
    343 			rio_t *rp;
    344 			int i;
    345 
    346 			q_stats = (struct rio_stats *)addr;
    347 			if ((rqp = altq_lookup(q_stats->iface.rio_ifname,
    348 					       ALTQT_RIO)) == NULL) {
    349 				error = EBADF;
    350 				break;
    351 			}
    352 
    353 			rp = rqp->rq_rio;
    354 
    355 			q_stats->q_limit = qlimit(rqp->rq_q);
    356 			q_stats->weight	= rp->rio_weight;
    357 			q_stats->flags = rp->rio_flags;
    358 
    359 			for (i = 0; i < RIO_NDROPPREC; i++) {
    360 				q_stats->q_len[i] = rp->rio_precstate[i].qlen;
    361 				bcopy(&rp->q_stats[i], &q_stats->q_stats[i],
    362 				      sizeof(struct redstats));
    363 				q_stats->q_stats[i].q_avg =
    364 				    rp->rio_precstate[i].avg >> rp->rio_wshift;
    365 
    366 				q_stats->q_params[i].inv_pmax
    367 					= rp->rio_precstate[i].inv_pmax;
    368 				q_stats->q_params[i].th_min
    369 					= rp->rio_precstate[i].th_min;
    370 				q_stats->q_params[i].th_max
    371 					= rp->rio_precstate[i].th_max;
    372 			}
    373 		} while (0);
    374 		break;
    375 
    376 	case RIO_CONFIG:
    377 		do {
    378 			struct rio_conf *fc;
    379 			rio_t	*new;
    380 			int s, limit, i;
    381 
    382 			fc = (struct rio_conf *)addr;
    383 			if ((rqp = altq_lookup(fc->iface.rio_ifname,
    384 					       ALTQT_RIO)) == NULL) {
    385 				error = EBADF;
    386 				break;
    387 			}
    388 
    389 			new = rio_alloc(fc->rio_weight, &fc->q_params[0],
    390 					fc->rio_flags, fc->rio_pkttime);
    391 			if (new == NULL) {
    392 				error = ENOMEM;
    393 				break;
    394 			}
    395 
    396 			s = splnet();
    397 			_flushq(rqp->rq_q);
    398 			limit = fc->rio_limit;
    399 			if (limit < fc->q_params[RIO_NDROPPREC-1].th_max)
    400 				limit = fc->q_params[RIO_NDROPPREC-1].th_max;
    401 			qlimit(rqp->rq_q) = limit;
    402 
    403 			rio_destroy(rqp->rq_rio);
    404 			rqp->rq_rio = new;
    405 
    406 			splx(s);
    407 
    408 			/* write back new values */
    409 			fc->rio_limit = limit;
    410 			for (i = 0; i < RIO_NDROPPREC; i++) {
    411 				fc->q_params[i].inv_pmax =
    412 					rqp->rq_rio->rio_precstate[i].inv_pmax;
    413 				fc->q_params[i].th_min =
    414 					rqp->rq_rio->rio_precstate[i].th_min;
    415 				fc->q_params[i].th_max =
    416 					rqp->rq_rio->rio_precstate[i].th_max;
    417 			}
    418 		} while (0);
    419 		break;
    420 
    421 	case RIO_SETDEFAULTS:
    422 		do {
    423 			struct redparams *rp;
    424 			int i;
    425 
    426 			rp = (struct redparams *)addr;
    427 			for (i = 0; i < RIO_NDROPPREC; i++)
    428 				default_rio_params[i] = rp[i];
    429 		} while (0);
    430 		break;
    431 
    432 	default:
    433 		error = EINVAL;
    434 		break;
    435 	}
    436 
    437 	return error;
    438 }
    439 
    440 static int
    441 rio_detach(rqp)
    442 	rio_queue_t *rqp;
    443 {
    444 	rio_queue_t *tmp;
    445 	int error = 0;
    446 
    447 	if (ALTQ_IS_ENABLED(rqp->rq_ifq))
    448 		altq_disable(rqp->rq_ifq);
    449 
    450 	if ((error = altq_detach(rqp->rq_ifq)))
    451 		return (error);
    452 
    453 	if (rio_list == rqp)
    454 		rio_list = rqp->rq_next;
    455 	else {
    456 		for (tmp = rio_list; tmp != NULL; tmp = tmp->rq_next)
    457 			if (tmp->rq_next == rqp) {
    458 				tmp->rq_next = rqp->rq_next;
    459 				break;
    460 			}
    461 		if (tmp == NULL)
    462 			printf("rio_detach: no state found in rio_list!\n");
    463 	}
    464 
    465 	rio_destroy(rqp->rq_rio);
    466 	FREE(rqp->rq_q, M_DEVBUF);
    467 	FREE(rqp, M_DEVBUF);
    468 	return (error);
    469 }
    470 
    471 /*
    472  * rio support routines
    473  */
    474 static int
    475 rio_request(ifq, req, arg)
    476 	struct ifaltq *ifq;
    477 	int req;
    478 	void *arg;
    479 {
    480 	rio_queue_t *rqp = (rio_queue_t *)ifq->altq_disc;
    481 
    482 	switch (req) {
    483 	case ALTRQ_PURGE:
    484 		_flushq(rqp->rq_q);
    485 		if (ALTQ_IS_ENABLED(ifq))
    486 			ifq->ifq_len = 0;
    487 		break;
    488 	}
    489 	return (0);
    490 }
    491 
    492 
    493 rio_t *
    494 rio_alloc(weight, params, flags, pkttime)
    495 	int	weight;
    496 	struct redparams *params;
    497 	int	flags, pkttime;
    498 {
    499 	rio_t 	*rp;
    500 	int	w, i;
    501 	int	npkts_per_sec;
    502 
    503 	MALLOC(rp, rio_t *, sizeof(rio_t), M_DEVBUF, M_WAITOK);
    504 	if (rp == NULL)
    505 		return (NULL);
    506 	bzero(rp, sizeof(rio_t));
    507 
    508 	rp->rio_flags = flags;
    509 	if (pkttime == 0)
    510 		/* default packet time: 1000 bytes / 10Mbps * 8 * 1000000 */
    511 		rp->rio_pkttime = 800;
    512 	else
    513 		rp->rio_pkttime = pkttime;
    514 
    515 	if (weight != 0)
    516 		rp->rio_weight = weight;
    517 	else {
    518 		/* use derfault */
    519 		rp->rio_weight = W_WEIGHT;
    520 
    521 		/* when the link is very slow, adjust red parameters */
    522 		npkts_per_sec = 1000000 / rp->rio_pkttime;
    523 		if (npkts_per_sec < 50) {
    524 			/* up to about 400Kbps */
    525 			rp->rio_weight = W_WEIGHT_2;
    526 		} else if (npkts_per_sec < 300) {
    527 			/* up to about 2.4Mbps */
    528 			rp->rio_weight = W_WEIGHT_1;
    529 		}
    530 	}
    531 
    532 	/* calculate wshift.  weight must be power of 2 */
    533 	w = rp->rio_weight;
    534 	for (i = 0; w > 1; i++)
    535 		w = w >> 1;
    536 	rp->rio_wshift = i;
    537 	w = 1 << rp->rio_wshift;
    538 	if (w != rp->rio_weight) {
    539 		printf("invalid weight value %d for red! use %d\n",
    540 		       rp->rio_weight, w);
    541 		rp->rio_weight = w;
    542 	}
    543 
    544 	/* allocate weight table */
    545 	rp->rio_wtab = wtab_alloc(rp->rio_weight);
    546 
    547 	for (i = 0; i < RIO_NDROPPREC; i++) {
    548 		struct dropprec_state *prec = &rp->rio_precstate[i];
    549 
    550 		prec->avg = 0;
    551 		prec->idle = 1;
    552 
    553 		if (params == NULL || params[i].inv_pmax == 0)
    554 			prec->inv_pmax = default_rio_params[i].inv_pmax;
    555 		else
    556 			prec->inv_pmax = params[i].inv_pmax;
    557 		if (params == NULL || params[i].th_min == 0)
    558 			prec->th_min = default_rio_params[i].th_min;
    559 		else
    560 			prec->th_min = params[i].th_min;
    561 		if (params == NULL || params[i].th_max == 0)
    562 			prec->th_max = default_rio_params[i].th_max;
    563 		else
    564 			prec->th_max = params[i].th_max;
    565 
    566 		/*
    567 		 * th_min_s and th_max_s are scaled versions of th_min
    568 		 * and th_max to be compared with avg.
    569 		 */
    570 		prec->th_min_s = prec->th_min << (rp->rio_wshift + FP_SHIFT);
    571 		prec->th_max_s = prec->th_max << (rp->rio_wshift + FP_SHIFT);
    572 
    573 		/*
    574 		 * precompute probability denominator
    575 		 *  probd = (2 * (TH_MAX-TH_MIN) / pmax) in fixed-point
    576 		 */
    577 		prec->probd = (2 * (prec->th_max - prec->th_min)
    578 			       * prec->inv_pmax) << FP_SHIFT;
    579 
    580 		microtime(&prec->last);
    581 	}
    582 
    583 	return (rp);
    584 }
    585 
    586 void
    587 rio_destroy(rp)
    588 	rio_t *rp;
    589 {
    590 	wtab_destroy(rp->rio_wtab);
    591 	FREE(rp, M_DEVBUF);
    592 }
    593 
    594 void
    595 rio_getstats(rp, sp)
    596 	rio_t *rp;
    597 	struct redstats *sp;
    598 {
    599 	int i;
    600 
    601 	for (i = 0; i < RIO_NDROPPREC; i++) {
    602 		bcopy(&rp->q_stats[i], sp, sizeof(struct redstats));
    603 		sp->q_avg = rp->rio_precstate[i].avg >> rp->rio_wshift;
    604 		sp++;
    605 	}
    606 }
    607 
    608 /*
    609  * enqueue routine:
    610  *
    611  *	returns: 0 when successfully queued.
    612  *		 ENOBUFS when drop occurs.
    613  */
    614 static int
    615 rio_enqueue(ifq, m, pktattr)
    616 	struct ifaltq *ifq;
    617 	struct mbuf *m;
    618 	struct altq_pktattr *pktattr;
    619 {
    620 	rio_queue_t *rqp = (rio_queue_t *)ifq->altq_disc;
    621 	int error = 0;
    622 
    623 	if (rio_addq(rqp->rq_rio, rqp->rq_q, m, pktattr) == 0)
    624 		ifq->ifq_len++;
    625 	else
    626 		error = ENOBUFS;
    627 	return error;
    628 }
    629 
    630 #if (RIO_NDROPPREC == 3)
    631 /*
    632  * internally, a drop precedence value is converted to an index
    633  * starting from 0.
    634  */
    635 static int
    636 dscp2index(u_int8_t dscp)
    637 {
    638 	int dpindex = dscp & AF_DROPPRECMASK;
    639 
    640 	if (dpindex == 0)
    641 		return (0);
    642 	return ((dpindex >> 3) - 1);
    643 }
    644 #endif
    645 
    646 #if 1
    647 /*
    648  * kludge: when a packet is dequeued, we need to know its drop precedence
    649  * in order to keep the queue length of each drop precedence.
    650  * use m_pkthdr.rcvif to pass this info.
    651  */
    652 #define	RIOM_SET_PRECINDEX(m, idx)	\
    653 	do { (m)->m_pkthdr.rcvif = (struct ifnet *)((long)(idx)); } while (0)
    654 #define	RIOM_GET_PRECINDEX(m)	\
    655 	({ long idx; idx = (long)((m)->m_pkthdr.rcvif); \
    656 	(m)->m_pkthdr.rcvif = NULL; idx; })
    657 #endif
    658 
    659 int
    660 rio_addq(rp, q, m, pktattr)
    661 	rio_t *rp;
    662 	class_queue_t *q;
    663 	struct mbuf *m;
    664 	struct altq_pktattr *pktattr;
    665 {
    666 	int avg, droptype;
    667 	u_int8_t dsfield, odsfield;
    668 	int dpindex, i, n, t;
    669 	struct timeval now;
    670 	struct dropprec_state *prec;
    671 
    672 	dsfield = odsfield = read_dsfield(m, pktattr);
    673 	dpindex = dscp2index(dsfield);
    674 
    675 	/*
    676 	 * update avg of the precedence states whose drop precedence
    677 	 * is larger than or equal to the drop precedence of the packet
    678 	 */
    679 	now.tv_sec = 0;
    680 	for (i = dpindex; i < RIO_NDROPPREC; i++) {
    681 		prec = &rp->rio_precstate[i];
    682 		avg = prec->avg;
    683 		if (prec->idle) {
    684 			prec->idle = 0;
    685 			if (now.tv_sec == 0)
    686 				microtime(&now);
    687 			t = (now.tv_sec - prec->last.tv_sec);
    688 			if (t > 60)
    689 				avg = 0;
    690 			else {
    691 				t = t * 1000000 +
    692 					(now.tv_usec - prec->last.tv_usec);
    693 				n = t / rp->rio_pkttime;
    694 				/* calculate (avg = (1 - Wq)^n * avg) */
    695 				if (n > 0)
    696 					avg = (avg >> FP_SHIFT) *
    697 						pow_w(rp->rio_wtab, n);
    698 			}
    699 		}
    700 
    701 		/* run estimator. (avg is scaled by WEIGHT in fixed-point) */
    702 		avg += (prec->qlen << FP_SHIFT) - (avg >> rp->rio_wshift);
    703 		prec->avg = avg;		/* save the new value */
    704 		/*
    705 		 * count keeps a tally of arriving traffic that has not
    706 		 * been dropped.
    707 		 */
    708 		prec->count++;
    709 	}
    710 
    711 	prec = &rp->rio_precstate[dpindex];
    712 	avg = prec->avg;
    713 
    714 	/* see if we drop early */
    715 	droptype = DTYPE_NODROP;
    716 	if (avg >= prec->th_min_s && prec->qlen > 1) {
    717 		if (avg >= prec->th_max_s) {
    718 			/* avg >= th_max: forced drop */
    719 			droptype = DTYPE_FORCED;
    720 		} else if (prec->old == 0) {
    721 			/* first exceeds th_min */
    722 			prec->count = 1;
    723 			prec->old = 1;
    724 		} else if (drop_early((avg - prec->th_min_s) >> rp->rio_wshift,
    725 				      prec->probd, prec->count)) {
    726 			/* unforced drop by red */
    727 			droptype = DTYPE_EARLY;
    728 		}
    729 	} else {
    730 		/* avg < th_min */
    731 		prec->old = 0;
    732 	}
    733 
    734 	/*
    735 	 * if the queue length hits the hard limit, it's a forced drop.
    736 	 */
    737 	if (droptype == DTYPE_NODROP && qlen(q) >= qlimit(q))
    738 		droptype = DTYPE_FORCED;
    739 
    740 	if (droptype != DTYPE_NODROP) {
    741 		/* always drop incoming packet (as opposed to randomdrop) */
    742 		for (i = dpindex; i < RIO_NDROPPREC; i++)
    743 			rp->rio_precstate[i].count = 0;
    744 #ifdef RIO_STATS
    745 		if (droptype == DTYPE_EARLY)
    746 			rp->q_stats[dpindex].drop_unforced++;
    747 		else
    748 			rp->q_stats[dpindex].drop_forced++;
    749 		PKTCNTR_ADD(&rp->q_stats[dpindex].drop_cnt, m_pktlen(m));
    750 #endif
    751 		m_freem(m);
    752 		return (-1);
    753 	}
    754 
    755 	for (i = dpindex; i < RIO_NDROPPREC; i++)
    756 		rp->rio_precstate[i].qlen++;
    757 
    758 	/* save drop precedence index in mbuf hdr */
    759 	RIOM_SET_PRECINDEX(m, dpindex);
    760 
    761 	if (rp->rio_flags & RIOF_CLEARDSCP)
    762 		dsfield &= ~DSCP_MASK;
    763 
    764 	if (dsfield != odsfield)
    765 		write_dsfield(m, pktattr, dsfield);
    766 
    767 	_addq(q, m);
    768 
    769 #ifdef RIO_STATS
    770 	PKTCNTR_ADD(&rp->q_stats[dpindex].xmit_cnt, m_pktlen(m));
    771 #endif
    772 	return (0);
    773 }
    774 
    775 /*
    776  * dequeue routine:
    777  *	must be called in splnet.
    778  *
    779  *	returns: mbuf dequeued.
    780  *		 NULL when no packet is available in the queue.
    781  */
    782 
    783 static struct mbuf *
    784 rio_dequeue(ifq, op)
    785 	struct ifaltq *ifq;
    786 	int op;
    787 {
    788 	rio_queue_t *rqp = (rio_queue_t *)ifq->altq_disc;
    789 	struct mbuf *m = NULL;
    790 
    791 	if (op == ALTDQ_POLL)
    792 		return qhead(rqp->rq_q);
    793 
    794 	m = rio_getq(rqp->rq_rio, rqp->rq_q);
    795 	if (m != NULL)
    796 		ifq->ifq_len--;
    797 	return m;
    798 }
    799 
    800 struct mbuf *
    801 rio_getq(rp, q)
    802 	rio_t *rp;
    803 	class_queue_t *q;
    804 {
    805 	struct mbuf *m;
    806 	int dpindex, i;
    807 
    808 	if ((m = _getq(q)) == NULL)
    809 		return NULL;
    810 
    811 	dpindex = RIOM_GET_PRECINDEX(m);
    812 	for (i = dpindex; i < RIO_NDROPPREC; i++) {
    813 		if (--rp->rio_precstate[i].qlen == 0) {
    814 			if (rp->rio_precstate[i].idle == 0) {
    815 				rp->rio_precstate[i].idle = 1;
    816 				microtime(&rp->rio_precstate[i].last);
    817 			}
    818 		}
    819 	}
    820 	return (m);
    821 }
    822 
    823 #ifdef KLD_MODULE
    824 
    825 static struct altqsw rio_sw =
    826 	{"rio", rioopen, rioclose, rioioctl};
    827 
    828 ALTQ_MODULE(altq_rio, ALTQT_RIO, &rio_sw);
    829 
    830 #endif /* KLD_MODULE */
    831 
    832 #endif /* ALTQ_RIO */
    833