--- /dev/null
+/*
+ * Copyright (c) 2007-2012 Apple Inc. All rights reserved.
+ *
+ * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
+ *
+ * This file contains Original Code and/or Modifications of Original Code
+ * as defined in and that are subject to the Apple Public Source License
+ * Version 2.0 (the 'License'). You may not use this file except in
+ * compliance with the License. The rights granted to you under the License
+ * may not be used to create, or enable the creation or redistribution of,
+ * unlawful or unlicensed copies of an Apple operating system, or to
+ * circumvent, violate, or enable the circumvention or violation of, any
+ * terms of an Apple operating system software license agreement.
+ *
+ * Please obtain a copy of the License at
+ * http://www.opensource.apple.com/apsl/ and read it before using this file.
+ *
+ * The Original Code and all software distributed under the License are
+ * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
+ * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
+ * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
+ * Please see the License for the specific language governing rights and
+ * limitations under the License.
+ *
+ * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
+ */
+
+/* $OpenBSD: altq_red.c,v 1.14 2007/09/13 20:40:02 chl Exp $ */
+/* $KAME: altq_red.c,v 1.10 2002/04/03 05:38:51 kjc Exp $ */
+
+/*
+ * Copyright (C) 1997-2003
+ * 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 <sys/cdefs.h>
+
+#if CLASSQ_RED
+
+#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 <sys/kauth.h>
+
+#include <kern/zalloc.h>
+
+#include <net/if.h>
+
+#include <netinet/in.h>
+#include <netinet/in_systm.h>
+#include <netinet/ip.h>
+#if INET6
+#include <netinet/ip6.h>
+#endif
+
+#include <net/classq/classq_red.h>
+
+/*
+ * 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 allowed 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 lenght */
+
+#define RED_ZONE_MAX 32 /* maximum elements in zone */
+#define RED_ZONE_NAME "classq_red" /* zone name */
+
+static unsigned int red_size; /* size of zone element */
+static struct zone *red_zone; /* zone for red */
+
+/*
+ * 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".
+ */
+
+/* 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;
+
+static struct mbuf *red_getq_flow(struct red *, class_queue_t *,
+ u_int32_t, boolean_t);
+
+void
+red_init(void)
+{
+ _CASSERT(REDF_ECN4 == CLASSQF_ECN4);
+ _CASSERT(REDF_ECN6 == CLASSQF_ECN6);
+
+ red_size = sizeof (red_t);
+ red_zone = zinit(red_size, RED_ZONE_MAX * red_size,
+ 0, RED_ZONE_NAME);
+ if (red_zone == NULL) {
+ panic("%s: failed allocating %s", __func__, RED_ZONE_NAME);
+ /* NOTREACHED */
+ }
+ zone_change(red_zone, Z_EXPAND, TRUE);
+ zone_change(red_zone, Z_CALLERACCT, TRUE);
+}
+
+/*
+ * red support routines
+ */
+red_t *
+red_alloc(struct ifnet *ifp, int weight, int inv_pmax, int th_min,
+ int th_max, int flags, int pkttime)
+{
+ red_t *rp;
+ int w, i;
+ int npkts_per_sec;
+
+ VERIFY(ifp != NULL);
+
+ rp = zalloc(red_zone);
+ if (rp == NULL)
+ return (NULL);
+
+ bzero(rp, red_size);
+ 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 & REDF_USERFLAGS);
+ rp->red_ifp = ifp;
+
+ 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);
+ if (rp->red_wtab == NULL) {
+ red_destroy(rp);
+ return (NULL);
+ }
+
+ microuptime(&rp->red_last);
+ return (rp);
+}
+
+void
+red_destroy(red_t *rp)
+{
+ if (rp->red_wtab != NULL) {
+ wtab_destroy(rp->red_wtab);
+ rp->red_wtab = NULL;
+ }
+ zfree(red_zone, rp);
+}
+
+void
+red_getstats(red_t *rp, struct red_stats *sp)
+{
+ sp->q_avg = rp->red_avg >> rp->red_wshift;
+ sp->drop_forced = rp->red_stats.drop_forced;
+ sp->drop_unforced = rp->red_stats.drop_unforced;
+ sp->marked_packets = rp->red_stats.marked_packets;
+}
+
+int
+red_addq(red_t *rp, class_queue_t *q, struct mbuf *m, struct pf_mtag *tag)
+{
+ int avg, droptype;
+ int n;
+
+ 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;
+ microuptime(&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) &&
+ (tag->pftag_flags & PF_TAG_TCP) && /* only TCP */
+ mark_ecn(m, tag, rp->red_flags)) {
+ /* successfully marked. do not drop. */
+ rp->red_count = 0;
+ rp->red_stats.marked_packets++;
+ } 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 */
+ rp->red_stats.drop_unforced++;
+ } else {
+ /* forced drop, select a victim packet in the queue. */
+#ifdef RED_RANDOM_DROP
+ m = _getq_random(q);
+#endif
+ rp->red_stats.drop_forced++;
+ }
+ rp->red_count = 0;
+ IFCQ_CONVERT_LOCK(&rp->red_ifp->if_snd);
+ m_freem(m);
+ return (CLASSQEQ_DROPPED);
+ }
+ /* successfully queued */
+ return (CLASSQEQ_SUCCESS);
+}
+
+/*
+ * 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(int fp_len, int fp_probd, int count)
+{
+ 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) < (unsigned)fp_len) {
+ /* drop or mark */
+ return (1);
+ }
+ /* no drop/mark */
+ return (0);
+}
+
+static struct mbuf *
+red_getq_flow(struct red *rp, class_queue_t *q, u_int32_t flow, boolean_t purge)
+{
+#pragma unused(purge)
+ struct mbuf *m;
+
+ /* flow of 0 means head of queue */
+ if ((m = ((flow == 0) ? _getq(q) : _getq_flow(q, flow))) == NULL) {
+ if (rp->red_idle == 0) {
+ rp->red_idle = 1;
+ microuptime(&rp->red_last);
+ }
+ return (NULL);
+ }
+
+ rp->red_idle = 0;
+ return (m);
+}
+
+struct mbuf *
+red_getq(red_t *rp, class_queue_t *q)
+{
+ return (red_getq_flow(rp, q, 0, FALSE));
+}
+
+void
+red_purgeq(struct red *rp, class_queue_t *q, u_int32_t flow, u_int32_t *packets,
+ u_int32_t *bytes)
+{
+ u_int32_t cnt = 0, len = 0;
+ struct mbuf *m;
+
+ IFCQ_CONVERT_LOCK(&rp->red_ifp->if_snd);
+
+ while ((m = red_getq_flow(rp, q, flow, TRUE)) != NULL) {
+ cnt++;
+ len += m_pktlen(m);
+ m_freem(m);
+ }
+
+ if (packets != NULL)
+ *packets = cnt;
+ if (bytes != NULL)
+ *bytes = len;
+}
+
+void
+red_updateq(red_t *rp, cqev_t ev)
+{
+#pragma unused(rp, ev)
+ /* nothing for now */
+}
+
+int
+red_suspendq(red_t *rp, class_queue_t *q, boolean_t on)
+{
+#pragma unused(rp, q, on)
+ return (ENOTSUP);
+}
+
+/*
+ * 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(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);
+ }
+
+ w = _MALLOC(sizeof (struct wtab), M_DEVBUF, M_WAITOK|M_ZERO);
+ if (w == NULL)
+ return (NULL);
+
+ 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);
+}
+
+void
+wtab_destroy(struct wtab *w)
+{
+ struct wtab *prev;
+
+ if (--w->w_refcount > 0)
+ return;
+
+ 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);
+}
+
+int32_t
+pow_w(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);
+}
+
+#endif /* CLASSQ_RED */
projects / apple / xnu.git / blobdiff