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[dragonfly.git] / sys / net / altq / altq_rio.c

/*      $KAME: altq_rio.c,v 1.17 2003/07/10 12:07:49 kjc Exp $  */
/*      $DragonFly: src/sys/net/altq/altq_rio.c,v 1.3 2006/12/22 23:44:55 swildner Exp $ */

/*
 * Copyright (C) 1998-2003
 *      Sony Computer Science Laboratories Inc.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY SONY CSL AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL SONY CSL OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */
/*
 * Copyright (c) 1990-1994 Regents of the University of California.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *      This product includes software developed by the Computer Systems
 *      Engineering Group at Lawrence Berkeley Laboratory.
 * 4. Neither the name of the University nor of the Laboratory may be used
 *    to endorse or promote products derived from this software without
 *    specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#include "opt_altq.h"
#include "opt_inet.h"
#include "opt_inet6.h"

#ifdef ALTQ_RIO /* rio is enabled by ALTQ_RIO option in opt_altq.h */

#include <sys/param.h>
#include <sys/malloc.h>
#include <sys/mbuf.h>
#include <sys/socket.h>
#include <sys/systm.h>
#include <sys/errno.h>

#include <net/if.h>

#include <netinet/in.h>
#include <netinet/in_systm.h>
#include <netinet/ip.h>
#ifdef INET6
#include <netinet/ip6.h>
#endif

#include <net/pf/pfvar.h>
#include <net/altq/altq.h>
#include <net/altq/altq_red.h>
#include <net/altq/altq_rio.h>

/*
 * RIO: RED with IN/OUT bit
 *   described in
 *      "Explicit Allocation of Best Effort Packet Delivery Service"
 *      David D. Clark and Wenjia Fang, MIT Lab for Computer Science
 *      http://diffserv.lcs.mit.edu/Papers/exp-alloc-ddc-wf.{ps,pdf}
 *
 * this implementation is extended to support more than 2 drop precedence
 * values as described in RFC2597 (Assured Forwarding PHB Group).
 *
 */
/*
 * AF DS (differentiated service) codepoints.
 * (classes can be mapped to CBQ or H-FSC classes.)
 *
 *      0   1   2   3   4   5   6   7
 *    +---+---+---+---+---+---+---+---+
 *    |   CLASS   |DropPre| 0 |  CU   |
 *    +---+---+---+---+---+---+---+---+
 *
 *    class 1: 001
 *    class 2: 010
 *    class 3: 011
 *    class 4: 100
 *
 *    low drop prec:    01
 *    medium drop prec: 10
 *    high drop prec:   11
 */

/* normal red parameters */
#define W_WEIGHT        512     /* inverse of weight of EWMA (511/512) */
                                /* q_weight = 0.00195 */

/* red parameters for a slow link */
#define W_WEIGHT_1      128     /* inverse of weight of EWMA (127/128) */
                                /* q_weight = 0.0078125 */

/* red parameters for a very slow link (e.g., dialup) */
#define W_WEIGHT_2      64      /* inverse of weight of EWMA (63/64) */
                                /* q_weight = 0.015625 */

/* fixed-point uses 12-bit decimal places */
#define FP_SHIFT        12      /* fixed-point shift */

/* red parameters for drop probability */
#define INV_P_MAX       10      /* inverse of max drop probability */
#define TH_MIN           5      /* min threshold */
#define TH_MAX          15      /* max threshold */

#define RIO_LIMIT       60      /* default max queue lenght */
#define RIO_STATS               /* collect statistics */

/* default rio parameter values */
static struct redparams default_rio_params[RIO_NDROPPREC] = {
  /* th_min,             th_max,     inv_pmax */
  { TH_MAX * 2 + TH_MIN, TH_MAX * 3, INV_P_MAX }, /* low drop precedence */
  { TH_MAX + TH_MIN,     TH_MAX * 2, INV_P_MAX }, /* medium drop precedence */
  { TH_MIN,              TH_MAX,     INV_P_MAX }  /* high drop precedence */
};

/* internal function prototypes */
static int      dscp2index(uint8_t);
/* YYY Do we really need this? */
#define AF_DROPPRECMASK         0x18
#define DSCP_MASK       0xfc

rio_t *
rio_alloc(int weight, struct redparams *params, int flags, int pkttime)
{
        rio_t *rp;
        int w, i;
        int npkts_per_sec;

        rp = kmalloc(sizeof(*rp), M_ALTQ, M_WAITOK | M_ZERO);

        rp->rio_flags = flags;
        if (pkttime == 0)
                /* default packet time: 1000 bytes / 10Mbps * 8 * 1000000 */
                rp->rio_pkttime = 800;
        else
                rp->rio_pkttime = pkttime;

        if (weight != 0)
                rp->rio_weight = weight;
        else {
                /* use default */
                rp->rio_weight = W_WEIGHT;

                /* when the link is very slow, adjust red parameters */
                npkts_per_sec = 1000000 / rp->rio_pkttime;
                if (npkts_per_sec < 50) {
                        /* up to about 400Kbps */
                        rp->rio_weight = W_WEIGHT_2;
                } else if (npkts_per_sec < 300) {
                        /* up to about 2.4Mbps */
                        rp->rio_weight = W_WEIGHT_1;
                }
        }

        /* calculate wshift.  weight must be power of 2 */
        w = rp->rio_weight;
        for (i = 0; w > 1; i++)
                w = w >> 1;
        rp->rio_wshift = i;
        w = 1 << rp->rio_wshift;
        if (w != rp->rio_weight) {
                kprintf("invalid weight value %d for red! use %d\n",
                       rp->rio_weight, w);
                rp->rio_weight = w;
        }

        /* allocate weight table */
        rp->rio_wtab = wtab_alloc(rp->rio_weight);

        for (i = 0; i < RIO_NDROPPREC; i++) {
                struct dropprec_state *prec = &rp->rio_precstate[i];

                prec->avg = 0;
                prec->idle = 1;

                if (params == NULL || params[i].inv_pmax == 0)
                        prec->inv_pmax = default_rio_params[i].inv_pmax;
                else
                        prec->inv_pmax = params[i].inv_pmax;
                if (params == NULL || params[i].th_min == 0)
                        prec->th_min = default_rio_params[i].th_min;
                else
                        prec->th_min = params[i].th_min;
                if (params == NULL || params[i].th_max == 0)
                        prec->th_max = default_rio_params[i].th_max;
                else
                        prec->th_max = params[i].th_max;

                /*
                 * th_min_s and th_max_s are scaled versions of th_min
                 * and th_max to be compared with avg.
                 */
                prec->th_min_s = prec->th_min << (rp->rio_wshift + FP_SHIFT);
                prec->th_max_s = prec->th_max << (rp->rio_wshift + FP_SHIFT);

                /*
                 * precompute probability denominator
                 *  probd = (2 * (TH_MAX-TH_MIN) / pmax) in fixed-point
                 */
                prec->probd = (2 * (prec->th_max - prec->th_min)
                               * prec->inv_pmax) << FP_SHIFT;

                microtime(&prec->last);
        }

        return (rp);
}

void
rio_destroy(rio_t *rp)
{
        wtab_destroy(rp->rio_wtab);
        kfree(rp, M_ALTQ);
}

void
rio_getstats(rio_t *rp, struct redstats *sp)
{
        int i;

        for (i = 0; i < RIO_NDROPPREC; i++) {
                bcopy(&rp->q_stats[i], sp, sizeof(struct redstats));
                sp->q_avg = rp->rio_precstate[i].avg >> rp->rio_wshift;
                sp++;
        }
}

#if (RIO_NDROPPREC == 3)
/*
 * internally, a drop precedence value is converted to an index
 * starting from 0.
 */
static int
dscp2index(uint8_t dscp)
{
        int dpindex = dscp & AF_DROPPRECMASK;

        if (dpindex == 0)
                return (0);
        return ((dpindex >> 3) - 1);
}
#endif

#if 1
/*
 * kludge: when a packet is dequeued, we need to know its drop precedence
 * in order to keep the queue length of each drop precedence.
 * use m_pkthdr.rcvif to pass this info.
 */
#define RIOM_SET_PRECINDEX(m, idx)      \
        do { (m)->m_pkthdr.rcvif = (struct ifnet *)((long)(idx)); } while (0)
#define RIOM_GET_PRECINDEX(m)   \
        ({ long idx; idx = (long)((m)->m_pkthdr.rcvif); \
        (m)->m_pkthdr.rcvif = NULL; idx; })
#endif

int
rio_addq(rio_t *rp, class_queue_t *q, struct mbuf *m, struct altq_pktattr *pktattr)
{
        int avg, droptype;
        uint8_t dsfield, odsfield;
        int dpindex, i, n, t;
        struct timeval now;
        struct dropprec_state *prec;

        dsfield = odsfield = read_dsfield(m, pktattr);
        dpindex = dscp2index(dsfield);

        /*
         * update avg of the precedence states whose drop precedence
         * is larger than or equal to the drop precedence of the packet
         */
        now.tv_sec = 0;
        for (i = dpindex; i < RIO_NDROPPREC; i++) {
                prec = &rp->rio_precstate[i];
                avg = prec->avg;
                if (prec->idle) {
                        prec->idle = 0;
                        if (now.tv_sec == 0)
                                microtime(&now);
                        t = (now.tv_sec - prec->last.tv_sec);
                        if (t > 60)
                                avg = 0;
                        else {
                                t = t * 1000000 +
                                        (now.tv_usec - prec->last.tv_usec);
                                n = t / rp->rio_pkttime;
                                /* calculate (avg = (1 - Wq)^n * avg) */
                                if (n > 0)
                                        avg = (avg >> FP_SHIFT) *
                                                pow_w(rp->rio_wtab, n);
                        }
                }

                /* run estimator. (avg is scaled by WEIGHT in fixed-point) */
                avg += (prec->qlen << FP_SHIFT) - (avg >> rp->rio_wshift);
                prec->avg = avg;                /* save the new value */
                /*
                 * count keeps a tally of arriving traffic that has not
                 * been dropped.
                 */
                prec->count++;
        }

        prec = &rp->rio_precstate[dpindex];
        avg = prec->avg;

        /* see if we drop early */
        droptype = DTYPE_NODROP;
        if (avg >= prec->th_min_s && prec->qlen > 1) {
                if (avg >= prec->th_max_s) {
                        /* avg >= th_max: forced drop */
                        droptype = DTYPE_FORCED;
                } else if (prec->old == 0) {
                        /* first exceeds th_min */
                        prec->count = 1;
                        prec->old = 1;
                } else if (drop_early((avg - prec->th_min_s) >> rp->rio_wshift,
                                      prec->probd, prec->count)) {
                        /* unforced drop by red */
                        droptype = DTYPE_EARLY;
                }
        } else {
                /* avg < th_min */
                prec->old = 0;
        }

        /*
         * if the queue length hits the hard limit, it's a forced drop.
         */
        if (droptype == DTYPE_NODROP && qlen(q) >= qlimit(q))
                droptype = DTYPE_FORCED;

        if (droptype != DTYPE_NODROP) {
                /* always drop incoming packet (as opposed to randomdrop) */
                for (i = dpindex; i < RIO_NDROPPREC; i++)
                        rp->rio_precstate[i].count = 0;
#ifdef RIO_STATS
                if (droptype == DTYPE_EARLY)
                        rp->q_stats[dpindex].drop_unforced++;
                else
                        rp->q_stats[dpindex].drop_forced++;
                PKTCNTR_ADD(&rp->q_stats[dpindex].drop_cnt, m_pktlen(m));
#endif
                m_freem(m);
                return (-1);
        }

        for (i = dpindex; i < RIO_NDROPPREC; i++)
                rp->rio_precstate[i].qlen++;

        /* save drop precedence index in mbuf hdr */
        RIOM_SET_PRECINDEX(m, dpindex);

        if (rp->rio_flags & RIOF_CLEARDSCP)
                dsfield &= ~DSCP_MASK;

        if (dsfield != odsfield)
                write_dsfield(m, pktattr, dsfield);

        _addq(q, m);

#ifdef RIO_STATS
        PKTCNTR_ADD(&rp->q_stats[dpindex].xmit_cnt, m_pktlen(m));
#endif
        return (0);
}

struct mbuf *
rio_getq(rio_t *rp, class_queue_t *q)
{
        struct mbuf *m;
        int dpindex, i;

        if ((m = _getq(q)) == NULL)
                return (NULL);

        dpindex = RIOM_GET_PRECINDEX(m);
        for (i = dpindex; i < RIO_NDROPPREC; i++) {
                if (--rp->rio_precstate[i].qlen == 0) {
                        if (rp->rio_precstate[i].idle == 0) {
                                rp->rio_precstate[i].idle = 1;
                                microtime(&rp->rio_precstate[i].last);
                        }
                }
        }
        return (m);
}

#endif /* ALTQ_RIO */