bsd/net/classq/classq_fq_codel.c

   1 /*
   2  * Copyright (c) 2016-2017 Apple Inc. All rights reserved.
   3  *
   4  * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
   5  *
   6  * This file contains Original Code and/or Modifications of Original Code
   7  * as defined in and that are subject to the Apple Public Source License
   8  * Version 2.0 (the 'License'). You may not use this file except in
   9  * compliance with the License. The rights granted to you under the License
  10  * may not be used to create, or enable the creation or redistribution of,
  11  * unlawful or unlicensed copies of an Apple operating system, or to
  12  * circumvent, violate, or enable the circumvention or violation of, any
  13  * terms of an Apple operating system software license agreement.
  14  *
  15  * Please obtain a copy of the License at
  16  * http://www.opensource.apple.com/apsl/ and read it before using this file.
  17  *
  18  * The Original Code and all software distributed under the License are
  19  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  20  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  21  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  22  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  23  * Please see the License for the specific language governing rights and
  24  * limitations under the License.
  25  *
  26  * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
  27  */
  28
  29 #include <sys/cdefs.h>
  30 #include <sys/param.h>
  31 #include <sys/mbuf.h>
  32 #include <sys/socket.h>
  33 #include <sys/sockio.h>
  34 #include <sys/systm.h>
  35 #include <sys/sysctl.h>
  36 #include <sys/syslog.h>
  37 #include <sys/proc.h>
  38 #include <sys/errno.h>
  39 #include <sys/kernel.h>
  40 #include <sys/kauth.h>
  41 #include <kern/zalloc.h>
  42 #include <netinet/in.h>
  43
  44 #include <net/classq/classq.h>
  45 #include <net/classq/if_classq.h>
  46 #include <net/pktsched/pktsched.h>
  47 #include <net/pktsched/pktsched_fq_codel.h>
  48 #include <net/classq/classq_fq_codel.h>
  49
  50 static uint32_t flowq_size;                     /* size of flowq */
  51 static struct mcache *flowq_cache = NULL;       /* mcache for flowq */
  52
  53 #define FQ_ZONE_MAX     (32 * 1024)     /* across all interfaces */
  54
  55 #define DTYPE_NODROP    0       /* no drop */
  56 #define DTYPE_FORCED    1       /* a "forced" drop */
  57 #define DTYPE_EARLY     2       /* an "unforced" (early) drop */
  58
  59 void
  60 fq_codel_init(void)
  61 {
  62         if (flowq_cache != NULL)
  63                 return;
  64
  65         flowq_size = sizeof (fq_t);
  66         flowq_cache = mcache_create("fq.flowq", flowq_size, sizeof (uint64_t),
  67             0, MCR_SLEEP);
  68         if (flowq_cache == NULL) {
  69                 panic("%s: failed to allocate flowq_cache", __func__);
  70                 /* NOTREACHED */
  71         }
  72 }
  73
  74 void
  75 fq_codel_reap_caches(boolean_t purge)
  76 {
  77         mcache_reap_now(flowq_cache, purge);
  78 }
  79
  80 fq_t *
  81 fq_alloc(classq_pkt_type_t ptype)
  82 {
  83         fq_t *fq = NULL;
  84         fq = mcache_alloc(flowq_cache, MCR_SLEEP);
  85         if (fq == NULL) {
  86                 log(LOG_ERR, "%s: unable to allocate from flowq_cache\n");
  87                 return (NULL);
  88         }
  89
  90         bzero(fq, flowq_size);
  91         fq->fq_ptype = ptype;
  92         if (ptype == QP_MBUF) {
  93                 MBUFQ_INIT(&fq->fq_mbufq);
  94         }
  95         return (fq);
  96 }
  97
  98 void
  99 fq_destroy(fq_t *fq)
 100 {
 101         VERIFY(fq_empty(fq));
 102         VERIFY(!(fq->fq_flags & (FQF_NEW_FLOW | FQF_OLD_FLOW)));
 103         VERIFY(fq->fq_bytes == 0);
 104         mcache_free(flowq_cache, fq);
 105 }
 106
 107 static void
 108 fq_detect_dequeue_stall(fq_if_t *fqs, fq_t *flowq, fq_if_classq_t *fq_cl,
 109     u_int64_t *now)
 110 {
 111         u_int64_t maxgetqtime;
 112         if (FQ_IS_DELAYHIGH(flowq) || flowq->fq_getqtime == 0 ||
 113             fq_empty(flowq) ||
 114             flowq->fq_bytes < FQ_MIN_FC_THRESHOLD_BYTES)
 115                 return;
 116         maxgetqtime = flowq->fq_getqtime + fqs->fqs_update_interval;
 117         if ((*now) > maxgetqtime) {
 118                 /*
 119                  * there was no dequeue in an update interval worth of
 120                  * time. It means that the queue is stalled.
 121                  */
 122                 FQ_SET_DELAY_HIGH(flowq);
 123                 fq_cl->fcl_stat.fcl_dequeue_stall++;
 124         }
 125 }
 126
 127 void
 128 fq_head_drop(fq_if_t *fqs, fq_t *fq)
 129 {
 130         pktsched_pkt_t pkt;
 131         uint32_t *pkt_flags;
 132         uint64_t *pkt_timestamp;
 133         struct ifclassq *ifq = fqs->fqs_ifq;
 134
 135         _PKTSCHED_PKT_INIT(&pkt);
 136         if (fq_getq_flow_internal(fqs, fq, &pkt) == NULL)
 137                 return;
 138
 139         pktsched_get_pkt_vars(&pkt, &pkt_flags, &pkt_timestamp, NULL, NULL,
 140             NULL, NULL);
 141
 142         *pkt_timestamp = 0;
 143         if (pkt.pktsched_ptype == QP_MBUF)
 144                 *pkt_flags &= ~PKTF_PRIV_GUARDED;
 145
 146         IFCQ_DROP_ADD(ifq, 1, pktsched_get_pkt_len(&pkt));
 147         IFCQ_CONVERT_LOCK(ifq);
 148         pktsched_free_pkt(&pkt);
 149 }
 150
 151 int
 152 fq_addq(fq_if_t *fqs, pktsched_pkt_t *pkt, fq_if_classq_t *fq_cl)
 153 {
 154         int droptype = DTYPE_NODROP, fc_adv = 0, ret = CLASSQEQ_SUCCESS;
 155         u_int64_t now;
 156         fq_t *fq = NULL;
 157         uint64_t *pkt_timestamp;
 158         uint32_t *pkt_flags;
 159         uint32_t pkt_flowid, pkt_tx_start_seq;
 160         uint8_t pkt_proto, pkt_flowsrc;
 161
 162         pktsched_get_pkt_vars(pkt, &pkt_flags, &pkt_timestamp, &pkt_flowid,
 163             &pkt_flowsrc, &pkt_proto, &pkt_tx_start_seq);
 164
 165         if (pkt->pktsched_ptype == QP_MBUF) {
 166                 /* See comments in <rdar://problem/14040693> */
 167                 VERIFY(!(*pkt_flags & PKTF_PRIV_GUARDED));
 168                 *pkt_flags |= PKTF_PRIV_GUARDED;
 169         }
 170
 171         if (*pkt_timestamp > 0) {
 172                 now = *pkt_timestamp;
 173         } else {
 174                 struct timespec now_ts;
 175                 nanouptime(&now_ts);
 176                 now = (now_ts.tv_sec * NSEC_PER_SEC) + now_ts.tv_nsec;
 177                 *pkt_timestamp = now;
 178         }
 179
 180         /* find the flowq for this packet */
 181         fq = fq_if_hash_pkt(fqs, pkt_flowid, pktsched_get_pkt_svc(pkt),
 182             now, TRUE, pkt->pktsched_ptype);
 183         if (fq == NULL) {
 184                 /* drop the packet if we could not allocate a flow queue */
 185                 fq_cl->fcl_stat.fcl_drop_memfailure++;
 186                 IFCQ_CONVERT_LOCK(fqs->fqs_ifq);
 187                 return (CLASSQEQ_DROP);
 188         }
 189         VERIFY(fq->fq_ptype == pkt->pktsched_ptype);
 190
 191         fq_detect_dequeue_stall(fqs, fq, fq_cl, &now);
 192
 193         if (FQ_IS_DELAYHIGH(fq)) {
 194                 if ((fq->fq_flags & FQF_FLOWCTL_CAPABLE) &&
 195                     (*pkt_flags & PKTF_FLOW_ADV)) {
 196                         fc_adv = 1;
 197                         /*
 198                          * If the flow is suspended or it is not
 199                          * TCP, drop the packet
 200                          */
 201                         if (pkt_proto != IPPROTO_TCP) {
 202                                 droptype = DTYPE_EARLY;
 203                                 fq_cl->fcl_stat.fcl_drop_early++;
 204                         }
 205                 } else {
 206                         /*
 207                          * Need to drop a packet, instead of dropping this
 208                          * one, try to drop from the head of the queue
 209                          */
 210                         if (!fq_empty(fq)) {
 211                                 fq_head_drop(fqs, fq);
 212                                 droptype = DTYPE_NODROP;
 213                         } else {
 214                                 droptype = DTYPE_EARLY;
 215                         }
 216                         fq_cl->fcl_stat.fcl_drop_early++;
 217                 }
 218
 219         }
 220
 221         /* Set the return code correctly */
 222         if (fc_adv == 1 && droptype != DTYPE_FORCED) {
 223                 if (fq_if_add_fcentry(fqs, pkt, pkt_flowid, pkt_flowsrc,
 224                     fq_cl)) {
 225                         fq->fq_flags |= FQF_FLOWCTL_ON;
 226                         /* deliver flow control advisory error */
 227                         if (droptype == DTYPE_NODROP) {
 228                                 ret = CLASSQEQ_SUCCESS_FC;
 229                         } else {
 230                                 /* dropped due to flow control */
 231                                 ret = CLASSQEQ_DROP_FC;
 232                         }
 233                 } else {
 234                         /*
 235                          * if we could not flow control the flow, it is
 236                          * better to drop
 237                          */
 238                         droptype = DTYPE_FORCED;
 239                         ret = CLASSQEQ_DROP_FC;
 240                         fq_cl->fcl_stat.fcl_flow_control_fail++;
 241                 }
 242         }
 243
 244         /*
 245          * If the queue length hits the queue limit, drop a packet from the
 246          * front of the queue for a flow with maximum number of bytes. This
 247          * will penalize heavy and unresponsive flows. It will also avoid a
 248          * tail drop.
 249          */
 250         if (droptype == DTYPE_NODROP && fq_if_at_drop_limit(fqs)) {
 251                 if (fqs->fqs_large_flow == fq) {
 252                         /*
 253                          * Drop from the head of the current fq. Since a
 254                          * new packet will be added to the tail, it is ok
 255                          * to leave fq in place.
 256                          */
 257                         fq_head_drop(fqs, fq);
 258                 } else {
 259                         if (fqs->fqs_large_flow == NULL) {
 260                                 droptype = DTYPE_FORCED;
 261                                 fq_cl->fcl_stat.fcl_drop_overflow++;
 262                                 ret = CLASSQEQ_DROP;
 263
 264                                 /*
 265                                  * if this fq was freshly created and there
 266                                  * is nothing to enqueue, free it
 267                                  */
 268                                 if (fq_empty(fq) && !(fq->fq_flags &
 269                                     (FQF_NEW_FLOW | FQF_OLD_FLOW))) {
 270                                         fq_if_destroy_flow(fqs, fq_cl, fq);
 271                                         fq = NULL;
 272                                 }
 273                         } else {
 274                                 fq_if_drop_packet(fqs);
 275                         }
 276                 }
 277         }
 278
 279         if (droptype == DTYPE_NODROP) {
 280                 uint32_t pkt_len = pktsched_get_pkt_len(pkt);
 281                 fq_enqueue(fq, pkt->pktsched_pkt);
 282                 fq->fq_bytes += pkt_len;
 283                 fq_cl->fcl_stat.fcl_byte_cnt += pkt_len;
 284                 fq_cl->fcl_stat.fcl_pkt_cnt++;
 285
 286                 /*
 287                  * check if this queue will qualify to be the next
 288                  * victim queue
 289                  */
 290                 fq_if_is_flow_heavy(fqs, fq);
 291         } else {
 292                 IFCQ_CONVERT_LOCK(fqs->fqs_ifq);
 293                 return ((ret != CLASSQEQ_SUCCESS) ? ret : CLASSQEQ_DROP);
 294         }
 295
 296         /*
 297          * If the queue is not currently active, add it to the end of new
 298          * flows list for that service class.
 299          */
 300         if ((fq->fq_flags & (FQF_NEW_FLOW|FQF_OLD_FLOW)) == 0) {
 301                 VERIFY(STAILQ_NEXT(fq, fq_actlink) == NULL);
 302                 STAILQ_INSERT_TAIL(&fq_cl->fcl_new_flows, fq, fq_actlink);
 303                 fq->fq_flags |= FQF_NEW_FLOW;
 304
 305                 fq_cl->fcl_stat.fcl_newflows_cnt++;
 306
 307                 fq->fq_deficit = fq_cl->fcl_quantum;
 308         }
 309         return (ret);
 310 }
 311
 312 void *
 313 fq_getq_flow_internal(fq_if_t *fqs, fq_t *fq, pktsched_pkt_t *pkt)
 314 {
 315         void *p;
 316         uint32_t plen;
 317         fq_if_classq_t *fq_cl;
 318         struct ifclassq *ifq = fqs->fqs_ifq;
 319
 320         fq_dequeue(fq, p);
 321         if (p == NULL)
 322                 return (NULL);
 323
 324         pktsched_pkt_encap(pkt, fq->fq_ptype, p);
 325         plen = pktsched_get_pkt_len(pkt);
 326
 327         VERIFY(fq->fq_bytes >= plen);
 328         fq->fq_bytes -= plen;
 329
 330         fq_cl = &fqs->fqs_classq[fq->fq_sc_index];
 331         fq_cl->fcl_stat.fcl_byte_cnt -= plen;
 332         fq_cl->fcl_stat.fcl_pkt_cnt--;
 333         IFCQ_DEC_LEN(ifq);
 334         IFCQ_DEC_BYTES(ifq, plen);
 335
 336         /* Reset getqtime so that we don't count idle times */
 337         if (fq_empty(fq))
 338                 fq->fq_getqtime = 0;
 339
 340         return (p);
 341 }
 342
 343 void *
 344 fq_getq_flow(fq_if_t *fqs, fq_t *fq, pktsched_pkt_t *pkt)
 345 {
 346         void *p;
 347         fq_if_classq_t *fq_cl;
 348         u_int64_t now;
 349         int64_t qdelay = 0;
 350         struct timespec now_ts;
 351         uint32_t *pkt_flags, pkt_tx_start_seq;
 352         uint64_t *pkt_timestamp;
 353
 354         p = fq_getq_flow_internal(fqs, fq, pkt);
 355         if (p == NULL)
 356                 return (NULL);
 357
 358         pktsched_get_pkt_vars(pkt, &pkt_flags, &pkt_timestamp, NULL, NULL,
 359             NULL, &pkt_tx_start_seq);
 360
 361         nanouptime(&now_ts);
 362         now = (now_ts.tv_sec * NSEC_PER_SEC) + now_ts.tv_nsec;
 363
 364         /* this will compute qdelay in nanoseconds */
 365         if (now > *pkt_timestamp)
 366                 qdelay = now - *pkt_timestamp;
 367         fq_cl = &fqs->fqs_classq[fq->fq_sc_index];
 368
 369         if (fq->fq_min_qdelay == 0 ||
 370             (qdelay > 0 && (u_int64_t)qdelay < fq->fq_min_qdelay))
 371                 fq->fq_min_qdelay = qdelay;
 372         if (now >= fq->fq_updatetime) {
 373                 if (fq->fq_min_qdelay > fqs->fqs_target_qdelay) {
 374                         if (!FQ_IS_DELAYHIGH(fq))
 375                                 FQ_SET_DELAY_HIGH(fq);
 376                 } else {
 377                         FQ_CLEAR_DELAY_HIGH(fq);
 378                 }
 379
 380
 381                 /* Reset measured queue delay and update time */
 382                 fq->fq_updatetime = now + fqs->fqs_update_interval;
 383                 fq->fq_min_qdelay = 0;
 384         }
 385         if (!FQ_IS_DELAYHIGH(fq) || fq_empty(fq)) {
 386                 FQ_CLEAR_DELAY_HIGH(fq);
 387                 if (fq->fq_flags & FQF_FLOWCTL_ON) {
 388                         fq_if_flow_feedback(fqs, fq, fq_cl);
 389                 }
 390         }
 391
 392         if (fq_empty(fq)) {
 393                 /* Reset getqtime so that we don't count idle times */
 394                 fq->fq_getqtime = 0;
 395         } else {
 396                 fq->fq_getqtime = now;
 397         }
 398         fq_if_is_flow_heavy(fqs, fq);
 399
 400         *pkt_timestamp = 0;
 401         if (pkt->pktsched_ptype == QP_MBUF)
 402                 *pkt_flags &= ~PKTF_PRIV_GUARDED;
 403
 404         return (p);
 405 }