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NetBSD/sys/altq/altq_red.c

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/* $NetBSD: altq_red.c,v 1.13 2005/12/24 20:10:16 perry Exp $ */
/* $KAME: altq_red.c,v 1.9 2002/01/07 11:25:40 kjc Exp $ */
/*
* Copyright (C) 1997-2000
* 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 <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: altq_red.c,v 1.13 2005/12/24 20:10:16 perry Exp $");
#if defined(__FreeBSD__) || defined(__NetBSD__)
#include "opt_altq.h"
#if (__FreeBSD__ != 2)
#include "opt_inet.h"
#ifdef __FreeBSD__
#include "opt_inet6.h"
#endif
#endif
#endif /* __FreeBSD__ || __NetBSD__ */
#ifdef ALTQ_RED /* red is enabled by ALTQ_RED option in opt_altq.h */
#include <sys/param.h>
#include <sys/malloc.h>
#include <sys/mbuf.h>
#include <sys/socket.h>
#include <sys/sockio.h>
#include <sys/systm.h>
#include <sys/proc.h>
#include <sys/errno.h>
#include <sys/kernel.h>
#ifdef ALTQ_FLOWVALVE
#include <sys/queue.h>
#include <sys/time.h>
#endif
#include <net/if.h>
#include <net/if_types.h>
#include <netinet/in.h>
#include <netinet/in_systm.h>
#include <netinet/ip.h>
#ifdef INET6
#include <netinet/ip6.h>
#endif
#include <altq/altq.h>
#include <altq/altq_conf.h>
#include <altq/altq_red.h>
#ifdef ALTQ_FLOWVALVE
#include <altq/altq_flowvalve.h>
#endif
/*
* ALTQ/RED (Random Early Detection) implementation using 32-bit
* fixed-point calculation.
*
* written by kjc using the ns code as a reference.
* you can learn more about red and ns from Sally's home page at
* http://www-nrg.ee.lbl.gov/floyd/
*
* most of the red parameter values are fixed in this implementation
* to prevent fixed-point overflow/underflow.
* if you change the parameters, watch out for overflow/underflow!
*
* the parameters used are recommended values by Sally.
* the corresponding ns config looks:
* q_weight=0.00195
* minthresh=5 maxthresh=15 queue-size=60
* linterm=30
* dropmech=drop-tail
* bytes=false (can't be handled by 32-bit fixed-point)
* doubleq=false dqthresh=false
* wait=true
*/
/*
* alternative red parameters for a slow link.
*
* assume the queue length becomes from zero to L and keeps L, it takes
* N packets for q_avg to reach 63% of L.
* when q_weight is 0.002, N is about 500 packets.
* for a slow link like dial-up, 500 packets takes more than 1 minute!
* when q_weight is 0.008, N is about 127 packets.
* when q_weight is 0.016, N is about 63 packets.
* bursts of 50 packets are allowd for 0.002, bursts of 25 packets
* are allowed for 0.016.
* see Sally's paper for more details.
*/
/* 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 RED_LIMIT 60 /* default max queue length */
/*
* our default policy for forced-drop is drop-tail.
* (in altq-1.1.2 or earlier, the default was random-drop.
* but it makes more sense to punish the cause of the surge.)
* to switch to the random-drop policy, define "RED_RANDOM_DROP".
*/
#ifdef ALTQ_FLOWVALVE
/*
* flow-valve is an extension to protect red from unresponsive flows
* and to promote end-to-end congestion control.
* flow-valve observes the average drop rates of the flows that have
* experienced packet drops in the recent past.
* when the average drop rate exceeds the threshold, the flow is
* blocked by the flow-valve. the trapped flow should back off
* exponentially to escape from the flow-valve.
*/
#ifdef RED_RANDOM_DROP
#error "random-drop can't be used with flow-valve!"
#endif
#endif /* ALTQ_FLOWVALVE */
/* red_list keeps all red_queue_t's allocated. */
static red_queue_t *red_list = NULL;
/* default red parameter values */
static int default_th_min = TH_MIN;
static int default_th_max = TH_MAX;
static int default_inv_pmax = INV_P_MAX;
/* internal function prototypes */
static int red_enqueue __P((struct ifaltq *, struct mbuf *,
struct altq_pktattr *));
static struct mbuf *red_dequeue __P((struct ifaltq *, int));
static int red_request __P((struct ifaltq *, int, void *));
static void red_purgeq __P((red_queue_t *));
static int red_detach __P((red_queue_t *));
#ifdef ALTQ_FLOWVALVE
static inline struct fve *flowlist_lookup __P((struct flowvalve *,
struct altq_pktattr *, struct timeval *));
static inline struct fve *flowlist_reclaim __P((struct flowvalve *,
struct altq_pktattr *));
static inline void flowlist_move_to_head __P((struct flowvalve *,
struct fve *));
static inline int fv_p2f __P((struct flowvalve *, int));
static struct flowvalve *fv_alloc __P((struct red *));
static void fv_destroy __P((struct flowvalve *));
static int fv_checkflow __P((struct flowvalve *, struct altq_pktattr *,
struct fve **));
static void fv_dropbyred __P((struct flowvalve *fv, struct altq_pktattr *,
struct fve *));
#endif
/*
* red device interface
*/
altqdev_decl(red);
int
redopen(dev, flag, fmt, l)
dev_t dev;
int flag, fmt;
struct lwp *l;
{
/* everything will be done when the queueing scheme is attached. */
return 0;
}
int
redclose(dev, flag, fmt, l)
dev_t dev;
int flag, fmt;
struct lwp *l;
{
red_queue_t *rqp;
int err, error = 0;
while ((rqp = red_list) != NULL) {
/* destroy all */
err = red_detach(rqp);
if (err != 0 && error == 0)
error = err;
}
return error;
}
int
redioctl(dev, cmd, addr, flag, l)
dev_t dev;
ioctlcmd_t cmd;
caddr_t addr;
int flag;
struct lwp *l;
{
red_queue_t *rqp;
struct red_interface *ifacep;
struct ifnet *ifp;
struct proc *p = l->l_proc;
int error = 0;
/* check super-user privilege */
switch (cmd) {
case RED_GETSTATS:
break;
default:
#if (__FreeBSD_version > 400000)
if ((error = suser(p)) != 0)
#else
if ((error = suser(p->p_ucred, &p->p_acflag)) != 0)
#endif
return (error);
break;
}
switch (cmd) {
case RED_ENABLE:
ifacep = (struct red_interface *)addr;
if ((rqp = altq_lookup(ifacep->red_ifname, ALTQT_RED)) == NULL) {
error = EBADF;
break;
}
error = altq_enable(rqp->rq_ifq);
break;
case RED_DISABLE:
ifacep = (struct red_interface *)addr;
if ((rqp = altq_lookup(ifacep->red_ifname, ALTQT_RED)) == NULL) {
error = EBADF;
break;
}
error = altq_disable(rqp->rq_ifq);
break;
case RED_IF_ATTACH:
ifp = ifunit(((struct red_interface *)addr)->red_ifname);
if (ifp == NULL) {
error = ENXIO;
break;
}
/* allocate and initialize red_queue_t */
MALLOC(rqp, red_queue_t *, sizeof(red_queue_t), M_DEVBUF, M_WAITOK);
if (rqp == NULL) {
error = ENOMEM;
break;
}
(void)memset(rqp, 0, sizeof(red_queue_t));
MALLOC(rqp->rq_q, class_queue_t *, sizeof(class_queue_t),
M_DEVBUF, M_WAITOK);
if (rqp->rq_q == NULL) {
FREE(rqp, M_DEVBUF);
error = ENOMEM;
break;
}
(void)memset(rqp->rq_q, 0, sizeof(class_queue_t));
rqp->rq_red = red_alloc(0, 0, 0, 0, 0, 0);
if (rqp->rq_red == NULL) {
FREE(rqp->rq_q, M_DEVBUF);
FREE(rqp, M_DEVBUF);
error = ENOMEM;
break;
}
rqp->rq_ifq = &ifp->if_snd;
qtail(rqp->rq_q) = NULL;
qlen(rqp->rq_q) = 0;
qlimit(rqp->rq_q) = RED_LIMIT;
qtype(rqp->rq_q) = Q_RED;
/*
* set RED to this ifnet structure.
*/
error = altq_attach(rqp->rq_ifq, ALTQT_RED, rqp,
red_enqueue, red_dequeue, red_request,
NULL, NULL);
if (error) {
red_destroy(rqp->rq_red);
FREE(rqp->rq_q, M_DEVBUF);
FREE(rqp, M_DEVBUF);
break;
}
/* add this state to the red list */
rqp->rq_next = red_list;
red_list = rqp;
break;
case RED_IF_DETACH:
ifacep = (struct red_interface *)addr;
if ((rqp = altq_lookup(ifacep->red_ifname, ALTQT_RED)) == NULL) {
error = EBADF;
break;
}
error = red_detach(rqp);
break;
case RED_GETSTATS:
do {
struct red_stats *q_stats;
red_t *rp;
q_stats = (struct red_stats *)addr;
if ((rqp = altq_lookup(q_stats->iface.red_ifname,
ALTQT_RED)) == NULL) {
error = EBADF;
break;
}
q_stats->q_len = qlen(rqp->rq_q);
q_stats->q_limit = qlimit(rqp->rq_q);
rp = rqp->rq_red;
q_stats->q_avg = rp->red_avg >> rp->red_wshift;
q_stats->xmit_cnt = rp->red_stats.xmit_cnt;
q_stats->drop_cnt = rp->red_stats.drop_cnt;
q_stats->drop_forced = rp->red_stats.drop_forced;
q_stats->drop_unforced = rp->red_stats.drop_unforced;
q_stats->marked_packets = rp->red_stats.marked_packets;
q_stats->weight = rp->red_weight;
q_stats->inv_pmax = rp->red_inv_pmax;
q_stats->th_min = rp->red_thmin;
q_stats->th_max = rp->red_thmax;
#ifdef ALTQ_FLOWVALVE
if (rp->red_flowvalve != NULL) {
struct flowvalve *fv = rp->red_flowvalve;
q_stats->fv_flows = fv->fv_flows;
q_stats->fv_pass = fv->fv_stats.pass;
q_stats->fv_predrop = fv->fv_stats.predrop;
q_stats->fv_alloc = fv->fv_stats.alloc;
q_stats->fv_escape = fv->fv_stats.escape;
} else {
#endif /* ALTQ_FLOWVALVE */
q_stats->fv_flows = 0;
q_stats->fv_pass = 0;
q_stats->fv_predrop = 0;
q_stats->fv_alloc = 0;
q_stats->fv_escape = 0;
#ifdef ALTQ_FLOWVALVE
}
#endif /* ALTQ_FLOWVALVE */
} while (0);
break;
case RED_CONFIG:
do {
struct red_conf *fc;
red_t *new;
int s, limit;
fc = (struct red_conf *)addr;
if ((rqp = altq_lookup(fc->iface.red_ifname,
ALTQT_RED)) == NULL) {
error = EBADF;
break;
}
new = red_alloc(fc->red_weight,
fc->red_inv_pmax,
fc->red_thmin,
fc->red_thmax,
fc->red_flags,
fc->red_pkttime);
if (new == NULL) {
error = ENOMEM;
break;
}
s = splnet();
red_purgeq(rqp);
limit = fc->red_limit;
if (limit < fc->red_thmax)
limit = fc->red_thmax;
qlimit(rqp->rq_q) = limit;
fc->red_limit = limit; /* write back the new value */
red_destroy(rqp->rq_red);
rqp->rq_red = new;
splx(s);
/* write back new values */
fc->red_limit = limit;
fc->red_inv_pmax = rqp->rq_red->red_inv_pmax;
fc->red_thmin = rqp->rq_red->red_thmin;
fc->red_thmax = rqp->rq_red->red_thmax;
} while (0);
break;
case RED_SETDEFAULTS:
do {
struct redparams *rp;
rp = (struct redparams *)addr;
default_th_min = rp->th_min;
default_th_max = rp->th_max;
default_inv_pmax = rp->inv_pmax;
} while (0);
break;
default:
error = EINVAL;
break;
}
return error;
}
static int
red_detach(rqp)
red_queue_t *rqp;
{
red_queue_t *tmp;
int error = 0;
if (ALTQ_IS_ENABLED(rqp->rq_ifq))
altq_disable(rqp->rq_ifq);
if ((error = altq_detach(rqp->rq_ifq)))
return (error);
if (red_list == rqp)
red_list = rqp->rq_next;
else {
for (tmp = red_list; tmp != NULL; tmp = tmp->rq_next)
if (tmp->rq_next == rqp) {
tmp->rq_next = rqp->rq_next;
break;
}
if (tmp == NULL)
printf("red_detach: no state found in red_list!\n");
}
red_destroy(rqp->rq_red);
FREE(rqp->rq_q, M_DEVBUF);
FREE(rqp, M_DEVBUF);
return (error);
}
/*
* red support routines
*/
red_t *
red_alloc(weight, inv_pmax, th_min, th_max, flags, pkttime)
int weight, inv_pmax, th_min, th_max;
int flags, pkttime;
{
red_t *rp;
int w, i;
int npkts_per_sec;
MALLOC(rp, red_t *, sizeof(red_t), M_DEVBUF, M_WAITOK);
if (rp == NULL)
return (NULL);
(void)memset(rp, 0, sizeof(red_t));
rp->red_avg = 0;
rp->red_idle = 1;
if (weight == 0)
rp->red_weight = W_WEIGHT;
else
rp->red_weight = weight;
if (inv_pmax == 0)
rp->red_inv_pmax = default_inv_pmax;
else
rp->red_inv_pmax = inv_pmax;
if (th_min == 0)
rp->red_thmin = default_th_min;
else
rp->red_thmin = th_min;
if (th_max == 0)
rp->red_thmax = default_th_max;
else
rp->red_thmax = th_max;
rp->red_flags = flags;
if (pkttime == 0)
/* default packet time: 1000 bytes / 10Mbps * 8 * 1000000 */
rp->red_pkttime = 800;
else
rp->red_pkttime = pkttime;
if (weight == 0) {
/* when the link is very slow, adjust red parameters */
npkts_per_sec = 1000000 / rp->red_pkttime;
if (npkts_per_sec < 50) {
/* up to about 400Kbps */
rp->red_weight = W_WEIGHT_2;
} else if (npkts_per_sec < 300) {
/* up to about 2.4Mbps */
rp->red_weight = W_WEIGHT_1;
}
}
/* calculate wshift. weight must be power of 2 */
w = rp->red_weight;
for (i = 0; w > 1; i++)
w = w >> 1;
rp->red_wshift = i;
w = 1 << rp->red_wshift;
if (w != rp->red_weight) {
printf("invalid weight value %d for red! use %d\n",
rp->red_weight, w);
rp->red_weight = w;
}
/*
* thmin_s and thmax_s are scaled versions of th_min and th_max
* to be compared with avg.
*/
rp->red_thmin_s = rp->red_thmin << (rp->red_wshift + FP_SHIFT);
rp->red_thmax_s = rp->red_thmax << (rp->red_wshift + FP_SHIFT);
/*
* precompute probability denominator
* probd = (2 * (TH_MAX-TH_MIN) / pmax) in fixed-point
*/
rp->red_probd = (2 * (rp->red_thmax - rp->red_thmin)
* rp->red_inv_pmax) << FP_SHIFT;
/* allocate weight table */
rp->red_wtab = wtab_alloc(rp->red_weight);
microtime(&rp->red_last);
#ifdef ALTQ_FLOWVALVE
if (flags & REDF_FLOWVALVE)
rp->red_flowvalve = fv_alloc(rp);
/* if fv_alloc failes, flowvalve is just disabled */
#endif
return (rp);
}
void
red_destroy(rp)
red_t *rp;
{
#ifdef ALTQ_FLOWVALVE
if (rp->red_flowvalve != NULL)
fv_destroy(rp->red_flowvalve);
#endif
wtab_destroy(rp->red_wtab);
FREE(rp, M_DEVBUF);
}
void
red_getstats(rp, sp)
red_t *rp;
struct redstats *sp;
{
sp->q_avg = rp->red_avg >> rp->red_wshift;
sp->xmit_cnt = rp->red_stats.xmit_cnt;
sp->drop_cnt = rp->red_stats.drop_cnt;
sp->drop_forced = rp->red_stats.drop_forced;
sp->drop_unforced = rp->red_stats.drop_unforced;
sp->marked_packets = rp->red_stats.marked_packets;
}
/*
* enqueue routine:
*
* returns: 0 when successfully queued.
* ENOBUFS when drop occurs.
*/
static int
red_enqueue(ifq, m, pktattr)
struct ifaltq *ifq;
struct mbuf *m;
struct altq_pktattr *pktattr;
{
red_queue_t *rqp = (red_queue_t *)ifq->altq_disc;
if (red_addq(rqp->rq_red, rqp->rq_q, m, pktattr) < 0)
return ENOBUFS;
ifq->ifq_len++;
return 0;
}
int
red_addq(rp, q, m, pktattr)
red_t *rp;
class_queue_t *q;
struct mbuf *m;
struct altq_pktattr *pktattr;
{
int avg, droptype;
int n;
#ifdef ALTQ_FLOWVALVE
struct fve *fve = NULL;
if (rp->red_flowvalve != NULL && rp->red_flowvalve->fv_flows > 0)
if (fv_checkflow(rp->red_flowvalve, pktattr, &fve)) {
m_freem(m);
return (-1);
}
#endif
avg = rp->red_avg;
/*
* if we were idle, we pretend that n packets arrived during
* the idle period.
*/
if (rp->red_idle) {
struct timeval now;
int t;
rp->red_idle = 0;
microtime(&now);
t = (now.tv_sec - rp->red_last.tv_sec);
if (t > 60) {
/*
* being idle for more than 1 minute, set avg to zero.
* this prevents t from overflow.
*/
avg = 0;
} else {
t = t * 1000000 + (now.tv_usec - rp->red_last.tv_usec);
n = t / rp->red_pkttime - 1;
/* the following line does (avg = (1 - Wq)^n * avg) */
if (n > 0)
avg = (avg >> FP_SHIFT) *
pow_w(rp->red_wtab, n);
}
}
/* run estimator. (note: avg is scaled by WEIGHT in fixed-point) */
avg += (qlen(q) << FP_SHIFT) - (avg >> rp->red_wshift);
rp->red_avg = avg; /* save the new value */
/*
* red_count keeps a tally of arriving traffic that has not
* been dropped.
*/
rp->red_count++;
/* see if we drop early */
droptype = DTYPE_NODROP;
if (avg >= rp->red_thmin_s && qlen(q) > 1) {
if (avg >= rp->red_thmax_s) {
/* avg >= th_max: forced drop */
droptype = DTYPE_FORCED;
} else if (rp->red_old == 0) {
/* first exceeds th_min */
rp->red_count = 1;
rp->red_old = 1;
} else if (drop_early((avg - rp->red_thmin_s) >> rp->red_wshift,
rp->red_probd, rp->red_count)) {
/* mark or drop by red */
if ((rp->red_flags & REDF_ECN) &&
mark_ecn(m, pktattr, rp->red_flags)) {
/* successfully marked. do not drop. */
rp->red_count = 0;
#ifdef RED_STATS
rp->red_stats.marked_packets++;
#endif
} else {
/* unforced drop by red */
droptype = DTYPE_EARLY;
}
}
} else {
/* avg < th_min */
rp->red_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;
#ifdef RED_RANDOM_DROP
/* if successful or forced drop, enqueue this packet. */
if (droptype != DTYPE_EARLY)
_addq(q, m);
#else
/* if successful, enqueue this packet. */
if (droptype == DTYPE_NODROP)
_addq(q, m);
#endif
if (droptype != DTYPE_NODROP) {
if (droptype == DTYPE_EARLY) {
/* drop the incoming packet */
#ifdef RED_STATS
rp->red_stats.drop_unforced++;
#endif
} else {
/* forced drop, select a victim packet in the queue. */
#ifdef RED_RANDOM_DROP
m = _getq_random(q);
#endif
#ifdef RED_STATS
rp->red_stats.drop_forced++;
#endif
}
#ifdef RED_STATS
PKTCNTR_ADD(&rp->red_stats.drop_cnt, m_pktlen(m));
#endif
rp->red_count = 0;
#ifdef ALTQ_FLOWVALVE
if (rp->red_flowvalve != NULL)
fv_dropbyred(rp->red_flowvalve, pktattr, fve);
#endif
m_freem(m);
return (-1);
}
/* successfully queued */
#ifdef RED_STATS
PKTCNTR_ADD(&rp->red_stats.xmit_cnt, m_pktlen(m));
#endif
return (0);
}
/*
* early-drop probability is calculated as follows:
* prob = p_max * (avg - th_min) / (th_max - th_min)
* prob_a = prob / (2 - count*prob)
* = (avg-th_min) / (2*(th_max-th_min)*inv_p_max - count*(avg-th_min))
* here prob_a increases as successive undrop count increases.
* (prob_a starts from prob/2, becomes prob when (count == (1 / prob)),
* becomes 1 when (count >= (2 / prob))).
*/
int
drop_early(fp_len, fp_probd, count)
int fp_len; /* (avg - TH_MIN) in fixed-point */
int fp_probd; /* (2 * (TH_MAX-TH_MIN) / pmax) in fixed-point */
int count; /* how many successive undropped packets */
{
int d; /* denominator of drop-probability */
d = fp_probd - count * fp_len;
if (d <= 0)
/* count exceeds the hard limit: drop or mark */
return (1);
/*
* now the range of d is [1..600] in fixed-point. (when
* th_max-th_min=10 and p_max=1/30)
* drop probability = (avg - TH_MIN) / d
*/
if ((random() % d) < fp_len) {
/* drop or mark */
return (1);
}
/* no drop/mark */
return (0);
}
/*
* try to mark CE bit to the packet.
* returns 1 if successfully marked, 0 otherwise.
*/
int
mark_ecn(m, pktattr, flags)
struct mbuf *m;
struct altq_pktattr *pktattr;
int flags;
{
struct mbuf *m0;
if (pktattr == NULL ||
(pktattr->pattr_af != AF_INET && pktattr->pattr_af != AF_INET6))
return (0);
/* verify that pattr_hdr is within the mbuf data */
for (m0 = m; m0 != NULL; m0 = m0->m_next)
if ((pktattr->pattr_hdr >= m0->m_data) &&
(pktattr->pattr_hdr < m0->m_data + m0->m_len))
break;
if (m0 == NULL) {
/* ick, pattr_hdr is stale */
pktattr->pattr_af = AF_UNSPEC;
return (0);
}
switch (pktattr->pattr_af) {
case AF_INET:
if (flags & REDF_ECN4) {
struct ip *ip = (struct ip *)pktattr->pattr_hdr;
u_int8_t otos;
int sum;
if (ip->ip_v != 4)
return (0); /* version mismatch! */
if ((ip->ip_tos & IPTOS_ECN_MASK) == IPTOS_ECN_NOTECT)
return (0); /* not-ECT */
if ((ip->ip_tos & IPTOS_ECN_MASK) == IPTOS_ECN_CE)
return (1); /* already marked */
/*
* ecn-capable but not marked,
* mark CE and update checksum
*/
otos = ip->ip_tos;
ip->ip_tos |= IPTOS_ECN_CE;
/*
* update checksum (from RFC1624)
* HC' = ~(~HC + ~m + m')
*/
sum = ~ntohs(ip->ip_sum) & 0xffff;
sum += (~otos & 0xffff) + ip->ip_tos;
sum = (sum >> 16) + (sum & 0xffff);
sum += (sum >> 16); /* add carry */
ip->ip_sum = htons(~sum & 0xffff);
return (1);
}
break;
#ifdef INET6
case AF_INET6:
if (flags & REDF_ECN6) {
struct ip6_hdr *ip6 = (struct ip6_hdr *)pktattr->pattr_hdr;
u_int32_t flowlabel;
flowlabel = ntohl(ip6->ip6_flow);
if ((flowlabel >> 28) != 6)
return (0); /* version mismatch! */
if ((flowlabel & (IPTOS_ECN_MASK << 20)) ==
(IPTOS_ECN_NOTECT << 20))
return (0); /* not-ECT */
if ((flowlabel & (IPTOS_ECN_MASK << 20)) ==
(IPTOS_ECN_CE << 20))
return (1); /* already marked */
/*
* ecn-capable but not marked, mark CE
*/
flowlabel |= (IPTOS_ECN_CE << 20);
ip6->ip6_flow = htonl(flowlabel);
return (1);
}
break;
#endif /* INET6 */
}
/* not marked */
return (0);
}
/*
* dequeue routine:
* must be called in splnet.
*
* returns: mbuf dequeued.
* NULL when no packet is available in the queue.
*/
static struct mbuf *
red_dequeue(ifq, op)
struct ifaltq *ifq;
int op;
{
red_queue_t *rqp = (red_queue_t *)ifq->altq_disc;
struct mbuf *m;
if (op == ALTDQ_POLL)
return qhead(rqp->rq_q);
/* op == ALTDQ_REMOVE */
m = red_getq(rqp->rq_red, rqp->rq_q);
if (m != NULL)
ifq->ifq_len--;
return (m);
}
struct mbuf *
red_getq(rp, q)
red_t *rp;
class_queue_t *q;
{
struct mbuf *m;
if ((m = _getq(q)) == NULL) {
if (rp->red_idle == 0) {
rp->red_idle = 1;
microtime(&rp->red_last);
}
return NULL;
}
rp->red_idle = 0;
return (m);
}
static int
red_request(ifq, req, arg)
struct ifaltq *ifq;
int req;
void *arg;
{
red_queue_t *rqp = (red_queue_t *)ifq->altq_disc;
switch (req) {
case ALTRQ_PURGE:
red_purgeq(rqp);
break;
}
return (0);
}
static void
red_purgeq(rqp)
red_queue_t *rqp;
{
_flushq(rqp->rq_q);
if (ALTQ_IS_ENABLED(rqp->rq_ifq))
rqp->rq_ifq->ifq_len = 0;
}
/*
* helper routine to calibrate avg during idle.
* pow_w(wtab, n) returns (1 - Wq)^n in fixed-point
* here Wq = 1/weight and the code assumes Wq is close to zero.
*
* w_tab[n] holds ((1 - Wq)^(2^n)) in fixed-point.
*/
static struct wtab *wtab_list = NULL; /* pointer to wtab list */
struct wtab *
wtab_alloc(weight)
int weight;
{
struct wtab *w;
int i;
for (w = wtab_list; w != NULL; w = w->w_next)
if (w->w_weight == weight) {
w->w_refcount++;
return (w);
}
MALLOC(w, struct wtab *, sizeof(struct wtab), M_DEVBUF, M_WAITOK);
if (w == NULL)
panic("wtab_alloc: malloc failed!");
(void)memset(w, 0, sizeof(struct wtab));
w->w_weight = weight;
w->w_refcount = 1;
w->w_next = wtab_list;
wtab_list = w;
/* initialize the weight table */
w->w_tab[0] = ((weight - 1) << FP_SHIFT) / weight;
for (i = 1; i < 32; i++) {
w->w_tab[i] = (w->w_tab[i-1] * w->w_tab[i-1]) >> FP_SHIFT;
if (w->w_tab[i] == 0 && w->w_param_max == 0)
w->w_param_max = 1 << i;
}
return (w);
}
int
wtab_destroy(w)
struct wtab *w;
{
struct wtab *prev;
if (--w->w_refcount > 0)
return (0);
if (wtab_list == w)
wtab_list = w->w_next;
else for (prev = wtab_list; prev->w_next != NULL; prev = prev->w_next)
if (prev->w_next == w) {
prev->w_next = w->w_next;
break;
}
FREE(w, M_DEVBUF);
return (0);
}
int32_t
pow_w(w, n)
struct wtab *w;
int n;
{
int i, bit;
int32_t val;
if (n >= w->w_param_max)
return (0);
val = 1 << FP_SHIFT;
if (n <= 0)
return (val);
bit = 1;
i = 0;
while (n) {
if (n & bit) {
val = (val * w->w_tab[i]) >> FP_SHIFT;
n &= ~bit;
}
i++;
bit <<= 1;
}
return (val);
}
#ifdef ALTQ_FLOWVALVE
#define FV_PSHIFT 7 /* weight of average drop rate -- 1/128 */
#define FV_PSCALE(x) ((x) << FV_PSHIFT)
#define FV_PUNSCALE(x) ((x) >> FV_PSHIFT)
#define FV_FSHIFT 5 /* weight of average fraction -- 1/32 */
#define FV_FSCALE(x) ((x) << FV_FSHIFT)
#define FV_FUNSCALE(x) ((x) >> FV_FSHIFT)
#define FV_TIMER (3 * hz) /* timer value for garbage collector */
#define FV_FLOWLISTSIZE 64 /* how many flows in flowlist */
#define FV_N 10 /* update fve_f every FV_N packets */
#define FV_BACKOFFTHRESH 1 /* backoff threshold interval in second */
#define FV_TTHRESH 3 /* time threshold to delete fve */
#define FV_ALPHA 5 /* extra packet count */
#if (__FreeBSD_version > 300000)
#define FV_TIMESTAMP(tp) getmicrotime(tp)
#else
#define FV_TIMESTAMP(tp) { (*(tp)) = time; }
#endif
/*
* Brtt table: 127 entry table to convert drop rate (p) to
* the corresponding bandwidth fraction (f)
* the following equation is implemented to use scaled values,
* fve_p and fve_f, in the fixed point format.
*
* Brtt(p) = 1 /(sqrt(4*p/3) + min(1,3*sqrt(p*6/8)) * p * (1+32 * p*p))
* f = Brtt(p) / (max_th + alpha)
*/
#define BRTT_SIZE 128
#define BRTT_SHIFT 12
#define BRTT_MASK 0x0007f000
#define BRTT_PMAX (1 << (FV_PSHIFT + FP_SHIFT))
const int brtt_tab[BRTT_SIZE] = {
0, 1262010, 877019, 703694, 598706, 525854, 471107, 427728,
392026, 361788, 335598, 312506, 291850, 273158, 256081, 240361,
225800, 212247, 199585, 187788, 178388, 169544, 161207, 153333,
145888, 138841, 132165, 125836, 119834, 114141, 108739, 103612,
98747, 94129, 89746, 85585, 81637, 77889, 74333, 70957,
67752, 64711, 61824, 59084, 56482, 54013, 51667, 49440,
47325, 45315, 43406, 41591, 39866, 38227, 36667, 35184,
33773, 32430, 31151, 29933, 28774, 27668, 26615, 25611,
24653, 23740, 22868, 22035, 21240, 20481, 19755, 19062,
18399, 17764, 17157, 16576, 16020, 15487, 14976, 14487,
14017, 13567, 13136, 12721, 12323, 11941, 11574, 11222,
10883, 10557, 10243, 9942, 9652, 9372, 9103, 8844,
8594, 8354, 8122, 7898, 7682, 7474, 7273, 7079,
6892, 6711, 6536, 6367, 6204, 6046, 5893, 5746,
5603, 5464, 5330, 5201, 5075, 4954, 4836, 4722,
4611, 4504, 4400, 4299, 4201, 4106, 4014, 3924
};
static inline struct fve *
flowlist_lookup(fv, pktattr, now)
struct flowvalve *fv;
struct altq_pktattr *pktattr;
struct timeval *now;
{
struct fve *fve;
int flows;
struct ip *ip;
#ifdef INET6
struct ip6_hdr *ip6;
#endif
struct timeval tthresh;
if (pktattr == NULL)
return (NULL);
tthresh.tv_sec = now->tv_sec - FV_TTHRESH;
flows = 0;
/*
* search the flow list
*/
switch (pktattr->pattr_af) {
case AF_INET:
ip = (struct ip *)pktattr->pattr_hdr;
TAILQ_FOREACH(fve, &fv->fv_flowlist, fve_lru){
if (fve->fve_lastdrop.tv_sec == 0)
break;
if (fve->fve_lastdrop.tv_sec < tthresh.tv_sec) {
fve->fve_lastdrop.tv_sec = 0;
break;
}
if (fve->fve_flow.flow_af == AF_INET &&
fve->fve_flow.flow_ip.ip_src.s_addr ==
ip->ip_src.s_addr &&
fve->fve_flow.flow_ip.ip_dst.s_addr ==
ip->ip_dst.s_addr)
return (fve);
flows++;
}
break;
#ifdef INET6
case AF_INET6:
ip6 = (struct ip6_hdr *)pktattr->pattr_hdr;
TAILQ_FOREACH(fve, &fv->fv_flowlist, fve_lru){
if (fve->fve_lastdrop.tv_sec == 0)
break;
if (fve->fve_lastdrop.tv_sec < tthresh.tv_sec) {
fve->fve_lastdrop.tv_sec = 0;
break;
}
if (fve->fve_flow.flow_af == AF_INET6 &&
IN6_ARE_ADDR_EQUAL(&fve->fve_flow.flow_ip6.ip6_src,
&ip6->ip6_src) &&
IN6_ARE_ADDR_EQUAL(&fve->fve_flow.flow_ip6.ip6_dst,
&ip6->ip6_dst))
return (fve);
flows++;
}
break;
#endif /* INET6 */
default:
/* unknown protocol. no drop. */
return (NULL);
}
fv->fv_flows = flows; /* save the number of active fve's */
return (NULL);
}
static inline struct fve *
flowlist_reclaim(fv, pktattr)
struct flowvalve *fv;
struct altq_pktattr *pktattr;
{
struct fve *fve;
struct ip *ip;
#ifdef INET6
struct ip6_hdr *ip6;
#endif
/*
* get an entry from the tail of the LRU list.
*/
fve = TAILQ_LAST(&fv->fv_flowlist, fv_flowhead);
switch (pktattr->pattr_af) {
case AF_INET:
ip = (struct ip *)pktattr->pattr_hdr;
fve->fve_flow.flow_af = AF_INET;
fve->fve_flow.flow_ip.ip_src = ip->ip_src;
fve->fve_flow.flow_ip.ip_dst = ip->ip_dst;
break;
#ifdef INET6
case AF_INET6:
ip6 = (struct ip6_hdr *)pktattr->pattr_hdr;
fve->fve_flow.flow_af = AF_INET6;
fve->fve_flow.flow_ip6.ip6_src = ip6->ip6_src;
fve->fve_flow.flow_ip6.ip6_dst = ip6->ip6_dst;
break;
#endif
}
fve->fve_state = Green;
fve->fve_p = 0.0;
fve->fve_f = 0.0;
fve->fve_ifseq = fv->fv_ifseq - 1;
fve->fve_count = 0;
fv->fv_flows++;
#ifdef FV_STATS
fv->fv_stats.alloc++;
#endif
return (fve);
}
static inline void
flowlist_move_to_head(fv, fve)
struct flowvalve *fv;
struct fve *fve;
{
if (TAILQ_FIRST(&fv->fv_flowlist) != fve) {
TAILQ_REMOVE(&fv->fv_flowlist, fve, fve_lru);
TAILQ_INSERT_HEAD(&fv->fv_flowlist, fve, fve_lru);
}
}
/*
* allocate flowvalve structure
*/
static struct flowvalve *
fv_alloc(rp)
struct red *rp;
{
struct flowvalve *fv;
struct fve *fve;
int i, num;
num = FV_FLOWLISTSIZE;
MALLOC(fv, struct flowvalve *, sizeof(struct flowvalve),
M_DEVBUF, M_WAITOK);
if (fv == NULL)
return (NULL);
(void)memset(fv, 0, sizeof(struct flowvalve));
MALLOC(fv->fv_fves, struct fve *, sizeof(struct fve) * num,
M_DEVBUF, M_WAITOK);
if (fv->fv_fves == NULL) {
FREE(fv, M_DEVBUF);
return (NULL);
}
(void)memset(fv->fv_fves, 0, sizeof(struct fve) * num);
fv->fv_flows = 0;
TAILQ_INIT(&fv->fv_flowlist);
for (i = 0; i < num; i++) {
fve = &fv->fv_fves[i];
fve->fve_lastdrop.tv_sec = 0;
TAILQ_INSERT_TAIL(&fv->fv_flowlist, fve, fve_lru);
}
/* initialize drop rate threshold in scaled fixed-point */
fv->fv_pthresh = (FV_PSCALE(1) << FP_SHIFT) / rp->red_inv_pmax;
/* initialize drop rate to fraction table */
MALLOC(fv->fv_p2ftab, int *, sizeof(int) * BRTT_SIZE,
M_DEVBUF, M_WAITOK);
if (fv->fv_p2ftab == NULL) {
FREE(fv->fv_fves, M_DEVBUF);
FREE(fv, M_DEVBUF);
return (NULL);
}
/*
* create the p2f table.
* (shift is used to keep the precision)
*/
for (i = 1; i < BRTT_SIZE; i++) {
int f;
f = brtt_tab[i] << 8;
fv->fv_p2ftab[i] = (f / (rp->red_thmax + FV_ALPHA)) >> 8;
}
return (fv);
}
static void fv_destroy(fv)
struct flowvalve *fv;
{
FREE(fv->fv_p2ftab, M_DEVBUF);
FREE(fv->fv_fves, M_DEVBUF);
FREE(fv, M_DEVBUF);
}
static inline int
fv_p2f(fv, p)
struct flowvalve *fv;
int p;
{
int val, f;
if (p >= BRTT_PMAX)
f = fv->fv_p2ftab[BRTT_SIZE-1];
else if ((val = (p & BRTT_MASK)))
f = fv->fv_p2ftab[(val >> BRTT_SHIFT)];
else
f = fv->fv_p2ftab[1];
return (f);
}
/*
* check if an arriving packet should be pre-dropped.
* called from red_addq() when a packet arrives.
* returns 1 when the packet should be pre-dropped.
* should be called in splnet.
*/
static int
fv_checkflow(fv, pktattr, fcache)
struct flowvalve *fv;
struct altq_pktattr *pktattr;
struct fve **fcache;
{
struct fve *fve;
struct timeval now;
fv->fv_ifseq++;
FV_TIMESTAMP(&now);
if ((fve = flowlist_lookup(fv, pktattr, &now)) == NULL)
/* no matching entry in the flowlist */
return (0);
*fcache = fve;
/* update fraction f for every FV_N packets */
if (++fve->fve_count == FV_N) {
/*
* f = Wf * N / (fv_ifseq - fve_ifseq) + (1 - Wf) * f
*/
fve->fve_f =
(FV_N << FP_SHIFT) / (fv->fv_ifseq - fve->fve_ifseq)
+ fve->fve_f - FV_FUNSCALE(fve->fve_f);
fve->fve_ifseq = fv->fv_ifseq;
fve->fve_count = 0;
}
/*
* overpumping test
*/
if (fve->fve_state == Green && fve->fve_p > fv->fv_pthresh) {
int fthresh;
/* calculate a threshold */
fthresh = fv_p2f(fv, fve->fve_p);
if (fve->fve_f > fthresh)
fve->fve_state = Red;
}
if (fve->fve_state == Red) {
/*
* backoff test
*/
if (now.tv_sec - fve->fve_lastdrop.tv_sec > FV_BACKOFFTHRESH) {
/* no drop for at least FV_BACKOFFTHRESH sec */
fve->fve_p = 0;
fve->fve_state = Green;
#ifdef FV_STATS
fv->fv_stats.escape++;
#endif
} else {
/* block this flow */
flowlist_move_to_head(fv, fve);
fve->fve_lastdrop = now;
#ifdef FV_STATS
fv->fv_stats.predrop++;
#endif
return (1);
}
}
/*
* p = (1 - Wp) * p
*/
fve->fve_p -= FV_PUNSCALE(fve->fve_p);
if (fve->fve_p < 0)
fve->fve_p = 0;
#ifdef FV_STATS
fv->fv_stats.pass++;
#endif
return (0);
}
/*
* called from red_addq when a packet is dropped by red.
* should be called in splnet.
*/
static void fv_dropbyred(fv, pktattr, fcache)
struct flowvalve *fv;
struct altq_pktattr *pktattr;
struct fve *fcache;
{
struct fve *fve;
struct timeval now;
if (pktattr == NULL)
return;
FV_TIMESTAMP(&now);
if (fcache != NULL)
/* the fve of this packet is already cached */
fve = fcache;
else if ((fve = flowlist_lookup(fv, pktattr, &now)) == NULL)
fve = flowlist_reclaim(fv, pktattr);
flowlist_move_to_head(fv, fve);
/*
* update p: the following line cancels the update
* in fv_checkflow() and calculate
* p = Wp + (1 - Wp) * p
*/
fve->fve_p = (1 << FP_SHIFT) + fve->fve_p;
fve->fve_lastdrop = now;
}
#endif /* ALTQ_FLOWVALVE */
#ifdef KLD_MODULE
static struct altqsw red_sw =
{"red", redopen, redclose, redioctl};
ALTQ_MODULE(altq_red, ALTQT_RED, &red_sw);
#endif /* KLD_MODULE */
#endif /* ALTQ_RED */
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