sys/netinet/tcp_hostcache.c

   1 /*-
   2  * SPDX-License-Identifier: BSD-3-Clause
   3  *
   4  * Copyright (c) 2002 Andre Oppermann, Internet Business Solutions AG
   5  * All rights reserved.
   6  *
   7  * Redistribution and use in source and binary forms, with or without
   8  * modification, are permitted provided that the following conditions
   9  * are met:
  10  * 1. Redistributions of source code must retain the above copyright
  11  *    notice, this list of conditions and the following disclaimer.
  12  * 2. Redistributions in binary form must reproduce the above copyright
  13  *    notice, this list of conditions and the following disclaimer in the
  14  *    documentation and/or other materials provided with the distribution.
  15  * 3. The name of the author may not be used to endorse or promote
  16  *    products derived from this software without specific prior written
  17  *    permission.
  18  *
  19  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  29  * SUCH DAMAGE.
  30  */
  31
  32 /*
  33  * The tcp_hostcache moves the tcp-specific cached metrics from the routing
  34  * table to a dedicated structure indexed by the remote IP address.  It keeps
  35  * information on the measured TCP parameters of past TCP sessions to allow
  36  * better initial start values to be used with later connections to/from the
  37  * same source.  Depending on the network parameters (delay, max MTU,
  38  * congestion window) between local and remote sites, this can lead to
  39  * significant speed-ups for new TCP connections after the first one.
  40  *
  41  * Due to the tcp_hostcache, all TCP-specific metrics information in the
  42  * routing table have been removed.  The inpcb no longer keeps a pointer to
  43  * the routing entry, and protocol-initiated route cloning has been removed
  44  * as well.  With these changes, the routing table has gone back to being
  45  * more lightwight and only carries information related to packet forwarding.
  46  *
  47  * tcp_hostcache is designed for multiple concurrent access in SMP
  48  * environments and high contention.  All bucket rows have their own lock and
  49  * thus multiple lookups and modifies can be done at the same time as long as
  50  * they are in different bucket rows.  If a request for insertion of a new
  51  * record can't be satisfied, it simply returns an empty structure.  Nobody
  52  * and nothing outside of tcp_hostcache.c will ever point directly to any
  53  * entry in the tcp_hostcache.  All communication is done in an
  54  * object-oriented way and only functions of tcp_hostcache will manipulate
  55  * hostcache entries.  Otherwise, we are unable to achieve good behaviour in
  56  * concurrent access situations.  Since tcp_hostcache is only caching
  57  * information, there are no fatal consequences if we either can't satisfy
  58  * any particular request or have to drop/overwrite an existing entry because
  59  * of bucket limit memory constrains.
  60  */
  61
  62 /*
  63  * Many thanks to jlemon for basic structure of tcp_syncache which is being
  64  * followed here.
  65  */
  66
  67 #include <sys/cdefs.h>
  68 __FBSDID("$FreeBSD$");
  69
  70 #include "opt_inet6.h"
  71
  72 #include <sys/param.h>
  73 #include <sys/systm.h>
  74 #include <sys/hash.h>
  75 #include <sys/jail.h>
  76 #include <sys/kernel.h>
  77 #include <sys/lock.h>
  78 #include <sys/mutex.h>
  79 #include <sys/malloc.h>
  80 #include <sys/proc.h>
  81 #include <sys/sbuf.h>
  82 #include <sys/socket.h>
  83 #include <sys/socketvar.h>
  84 #include <sys/sysctl.h>
  85
  86 #include <net/vnet.h>
  87
  88 #include <netinet/in.h>
  89 #include <netinet/in_pcb.h>
  90 #include <netinet/tcp.h>
  91 #include <netinet/tcp_var.h>
  92
  93 #include <vm/uma.h>
  94
  95 TAILQ_HEAD(hc_qhead, hc_metrics);
  96
  97 struct hc_head {
  98         struct hc_qhead hch_bucket;
  99         u_int           hch_length;
 100         struct mtx      hch_mtx;
 101 };
 102
 103 struct hc_metrics {
 104         /* housekeeping */
 105         TAILQ_ENTRY(hc_metrics) rmx_q;
 106         struct          hc_head *rmx_head; /* head of bucket tail queue */
 107         struct          in_addr ip4;    /* IP address */
 108         struct          in6_addr ip6;   /* IP6 address */
 109         uint32_t        ip6_zoneid;     /* IPv6 scope zone id */
 110         /* endpoint specific values for tcp */
 111         uint32_t        rmx_mtu;        /* MTU for this path */
 112         uint32_t        rmx_ssthresh;   /* outbound gateway buffer limit */
 113         uint32_t        rmx_rtt;        /* estimated round trip time */
 114         uint32_t        rmx_rttvar;     /* estimated rtt variance */
 115         uint32_t        rmx_cwnd;       /* congestion window */
 116         uint32_t        rmx_sendpipe;   /* outbound delay-bandwidth product */
 117         uint32_t        rmx_recvpipe;   /* inbound delay-bandwidth product */
 118         /* TCP hostcache internal data */
 119         int             rmx_expire;     /* lifetime for object */
 120 #ifdef  TCP_HC_COUNTERS
 121         u_long          rmx_hits;       /* number of hits */
 122         u_long          rmx_updates;    /* number of updates */
 123 #endif
 124 };
 125
 126 struct tcp_hostcache {
 127         struct hc_head  *hashbase;
 128         uma_zone_t      zone;
 129         u_int           hashsize;
 130         u_int           hashmask;
 131         u_int           hashsalt;
 132         u_int           bucket_limit;
 133         u_int           cache_count;
 134         u_int           cache_limit;
 135         int             expire;
 136         int             prune;
 137         int             purgeall;
 138 };
 139
 140 /* Arbitrary values */
 141 #define TCP_HOSTCACHE_HASHSIZE          512
 142 #define TCP_HOSTCACHE_BUCKETLIMIT       30
 143 #define TCP_HOSTCACHE_EXPIRE            60*60   /* one hour */
 144 #define TCP_HOSTCACHE_PRUNE             5*60    /* every 5 minutes */
 145
 146 VNET_DEFINE_STATIC(struct tcp_hostcache, tcp_hostcache);
 147 #define V_tcp_hostcache         VNET(tcp_hostcache)
 148
 149 VNET_DEFINE_STATIC(struct callout, tcp_hc_callout);
 150 #define V_tcp_hc_callout        VNET(tcp_hc_callout)
 151
 152 static struct hc_metrics *tcp_hc_lookup(struct in_conninfo *, bool);
 153 static struct hc_metrics *tcp_hc_insert(struct in_conninfo *);
 154 static int sysctl_tcp_hc_list(SYSCTL_HANDLER_ARGS);
 155 static int sysctl_tcp_hc_histo(SYSCTL_HANDLER_ARGS);
 156 static int sysctl_tcp_hc_purgenow(SYSCTL_HANDLER_ARGS);
 157 static void tcp_hc_purge_internal(int);
 158 static void tcp_hc_purge(void *);
 159
 160 static SYSCTL_NODE(_net_inet_tcp, OID_AUTO, hostcache,
 161     CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
 162     "TCP Host cache");
 163
 164 VNET_DEFINE(int, tcp_use_hostcache) = 1;
 165 #define V_tcp_use_hostcache  VNET(tcp_use_hostcache)
 166 SYSCTL_INT(_net_inet_tcp_hostcache, OID_AUTO, enable, CTLFLAG_VNET | CTLFLAG_RW,
 167     &VNET_NAME(tcp_use_hostcache), 0,
 168     "Enable the TCP hostcache");
 169
 170 SYSCTL_UINT(_net_inet_tcp_hostcache, OID_AUTO, cachelimit, CTLFLAG_VNET | CTLFLAG_RDTUN,
 171     &VNET_NAME(tcp_hostcache.cache_limit), 0,
 172     "Overall entry limit for hostcache");
 173
 174 SYSCTL_UINT(_net_inet_tcp_hostcache, OID_AUTO, hashsize, CTLFLAG_VNET | CTLFLAG_RDTUN,
 175     &VNET_NAME(tcp_hostcache.hashsize), 0,
 176     "Size of TCP hostcache hashtable");
 177
 178 SYSCTL_UINT(_net_inet_tcp_hostcache, OID_AUTO, bucketlimit,
 179     CTLFLAG_VNET | CTLFLAG_RDTUN, &VNET_NAME(tcp_hostcache.bucket_limit), 0,
 180     "Per-bucket hash limit for hostcache");
 181
 182 SYSCTL_UINT(_net_inet_tcp_hostcache, OID_AUTO, count, CTLFLAG_VNET | CTLFLAG_RD,
 183     &VNET_NAME(tcp_hostcache.cache_count), 0,
 184     "Current number of entries in hostcache");
 185
 186 SYSCTL_INT(_net_inet_tcp_hostcache, OID_AUTO, expire, CTLFLAG_VNET | CTLFLAG_RW,
 187     &VNET_NAME(tcp_hostcache.expire), 0,
 188     "Expire time of TCP hostcache entries");
 189
 190 SYSCTL_INT(_net_inet_tcp_hostcache, OID_AUTO, prune, CTLFLAG_VNET | CTLFLAG_RW,
 191     &VNET_NAME(tcp_hostcache.prune), 0,
 192     "Time between purge runs");
 193
 194 SYSCTL_INT(_net_inet_tcp_hostcache, OID_AUTO, purge, CTLFLAG_VNET | CTLFLAG_RW,
 195     &VNET_NAME(tcp_hostcache.purgeall), 0,
 196     "Expire all entires on next purge run");
 197
 198 SYSCTL_PROC(_net_inet_tcp_hostcache, OID_AUTO, list,
 199     CTLTYPE_STRING | CTLFLAG_RD | CTLFLAG_SKIP | CTLFLAG_MPSAFE,
 200     0, 0, sysctl_tcp_hc_list, "A",
 201     "List of all hostcache entries");
 202
 203 SYSCTL_PROC(_net_inet_tcp_hostcache, OID_AUTO, histo,
 204     CTLTYPE_STRING | CTLFLAG_RD | CTLFLAG_SKIP | CTLFLAG_MPSAFE,
 205     0, 0, sysctl_tcp_hc_histo, "A",
 206     "Print a histogram of hostcache hashbucket utilization");
 207
 208 SYSCTL_PROC(_net_inet_tcp_hostcache, OID_AUTO, purgenow,
 209     CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_MPSAFE,
 210     NULL, 0, sysctl_tcp_hc_purgenow, "I",
 211     "Immediately purge all entries");
 212
 213 static MALLOC_DEFINE(M_HOSTCACHE, "hostcache", "TCP hostcache");
 214
 215 /* Use jenkins_hash32(), as in other parts of the tcp stack */
 216 #define HOSTCACHE_HASH(ip) \
 217         (jenkins_hash32((uint32_t *)(ip), 1, V_tcp_hostcache.hashsalt) & \
 218          V_tcp_hostcache.hashmask)
 219
 220 #define HOSTCACHE_HASH6(ip6)                            \
 221         (jenkins_hash32((uint32_t *)&((ip6)->s6_addr32[0]), 4, \
 222          V_tcp_hostcache.hashsalt) & \
 223          V_tcp_hostcache.hashmask)
 224
 225 #define THC_LOCK(h)             mtx_lock(&(h)->hch_mtx)
 226 #define THC_UNLOCK(h)           mtx_unlock(&(h)->hch_mtx)
 227
 228 void
 229 tcp_hc_init(void)
 230 {
 231         u_int cache_limit;
 232         int i;
 233
 234         /*
 235          * Initialize hostcache structures.
 236          */
 237         atomic_store_int(&V_tcp_hostcache.cache_count, 0);
 238         V_tcp_hostcache.hashsize = TCP_HOSTCACHE_HASHSIZE;
 239         V_tcp_hostcache.bucket_limit = TCP_HOSTCACHE_BUCKETLIMIT;
 240         V_tcp_hostcache.expire = TCP_HOSTCACHE_EXPIRE;
 241         V_tcp_hostcache.prune = TCP_HOSTCACHE_PRUNE;
 242         V_tcp_hostcache.hashsalt = arc4random();
 243
 244         TUNABLE_INT_FETCH("net.inet.tcp.hostcache.hashsize",
 245             &V_tcp_hostcache.hashsize);
 246         if (!powerof2(V_tcp_hostcache.hashsize)) {
 247                 printf("WARNING: hostcache hash size is not a power of 2.\n");
 248                 V_tcp_hostcache.hashsize = TCP_HOSTCACHE_HASHSIZE; /* default */
 249         }
 250         V_tcp_hostcache.hashmask = V_tcp_hostcache.hashsize - 1;
 251
 252         TUNABLE_INT_FETCH("net.inet.tcp.hostcache.bucketlimit",
 253             &V_tcp_hostcache.bucket_limit);
 254
 255         cache_limit = V_tcp_hostcache.hashsize * V_tcp_hostcache.bucket_limit;
 256         V_tcp_hostcache.cache_limit = cache_limit;
 257         TUNABLE_INT_FETCH("net.inet.tcp.hostcache.cachelimit",
 258             &V_tcp_hostcache.cache_limit);
 259         if (V_tcp_hostcache.cache_limit > cache_limit)
 260                 V_tcp_hostcache.cache_limit = cache_limit;
 261
 262         /*
 263          * Allocate the hash table.
 264          */
 265         V_tcp_hostcache.hashbase = (struct hc_head *)
 266             malloc(V_tcp_hostcache.hashsize * sizeof(struct hc_head),
 267                    M_HOSTCACHE, M_WAITOK | M_ZERO);
 268
 269         /*
 270          * Initialize the hash buckets.
 271          */
 272         for (i = 0; i < V_tcp_hostcache.hashsize; i++) {
 273                 TAILQ_INIT(&V_tcp_hostcache.hashbase[i].hch_bucket);
 274                 V_tcp_hostcache.hashbase[i].hch_length = 0;
 275                 mtx_init(&V_tcp_hostcache.hashbase[i].hch_mtx, "tcp_hc_entry",
 276                           NULL, MTX_DEF);
 277         }
 278
 279         /*
 280          * Allocate the hostcache entries.
 281          */
 282         V_tcp_hostcache.zone =
 283             uma_zcreate("hostcache", sizeof(struct hc_metrics),
 284             NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, 0);
 285         uma_zone_set_max(V_tcp_hostcache.zone, V_tcp_hostcache.cache_limit);
 286
 287         /*
 288          * Set up periodic cache cleanup.
 289          */
 290         callout_init(&V_tcp_hc_callout, 1);
 291         callout_reset(&V_tcp_hc_callout, V_tcp_hostcache.prune * hz,
 292             tcp_hc_purge, curvnet);
 293 }
 294
 295 #ifdef VIMAGE
 296 void
 297 tcp_hc_destroy(void)
 298 {
 299         int i;
 300
 301         callout_drain(&V_tcp_hc_callout);
 302
 303         /* Purge all hc entries. */
 304         tcp_hc_purge_internal(1);
 305
 306         /* Free the uma zone and the allocated hash table. */
 307         uma_zdestroy(V_tcp_hostcache.zone);
 308
 309         for (i = 0; i < V_tcp_hostcache.hashsize; i++)
 310                 mtx_destroy(&V_tcp_hostcache.hashbase[i].hch_mtx);
 311         free(V_tcp_hostcache.hashbase, M_HOSTCACHE);
 312 }
 313 #endif
 314
 315 /*
 316  * Internal function: look up an entry in the hostcache or return NULL.
 317  *
 318  * If an entry has been returned, the caller becomes responsible for
 319  * unlocking the bucket row after he is done reading/modifying the entry.
 320  */
 321 static struct hc_metrics *
 322 tcp_hc_lookup(struct in_conninfo *inc, bool update)
 323 {
 324         int hash;
 325         struct hc_head *hc_head;
 326         struct hc_metrics *hc_entry;
 327
 328         KASSERT(inc != NULL, ("%s: NULL in_conninfo", __func__));
 329
 330         /*
 331          * Hash the foreign ip address.
 332          */
 333         if (inc->inc_flags & INC_ISIPV6)
 334                 hash = HOSTCACHE_HASH6(&inc->inc6_faddr);
 335         else
 336                 hash = HOSTCACHE_HASH(&inc->inc_faddr);
 337
 338         hc_head = &V_tcp_hostcache.hashbase[hash];
 339
 340         /*
 341          * Acquire lock for this bucket row; we release the lock if we don't
 342          * find an entry, otherwise the caller has to unlock after he is
 343          * done.
 344          */
 345         THC_LOCK(hc_head);
 346
 347         /*
 348          * Iterate through entries in bucket row looking for a match.
 349          */
 350         TAILQ_FOREACH(hc_entry, &hc_head->hch_bucket, rmx_q) {
 351                 if (inc->inc_flags & INC_ISIPV6) {
 352                         /* XXX: check ip6_zoneid */
 353                         if (memcmp(&inc->inc6_faddr, &hc_entry->ip6,
 354                             sizeof(inc->inc6_faddr)) == 0)
 355                                 goto found;
 356                 } else {
 357                         if (memcmp(&inc->inc_faddr, &hc_entry->ip4,
 358                             sizeof(inc->inc_faddr)) == 0)
 359                                 goto found;
 360                 }
 361         }
 362
 363         /*
 364          * We were unsuccessful and didn't find anything.
 365          */
 366         THC_UNLOCK(hc_head);
 367         return (NULL);
 368
 369 found:
 370 #ifdef  TCP_HC_COUNTERS
 371         if (update)
 372                 hc_entry->rmx_updates++;
 373         else
 374                 hc_entry->rmx_hits++;
 375 #endif
 376         hc_entry->rmx_expire = V_tcp_hostcache.expire;
 377
 378         return (hc_entry);
 379 }
 380
 381 /*
 382  * Internal function: insert an entry into the hostcache or return NULL if
 383  * unable to allocate a new one.
 384  *
 385  * If an entry has been returned, the caller becomes responsible for
 386  * unlocking the bucket row after he is done reading/modifying the entry.
 387  */
 388 static struct hc_metrics *
 389 tcp_hc_insert(struct in_conninfo *inc)
 390 {
 391         int hash;
 392         struct hc_head *hc_head;
 393         struct hc_metrics *hc_entry;
 394
 395         KASSERT(inc != NULL, ("%s: NULL in_conninfo", __func__));
 396
 397         /*
 398          * Hash the foreign ip address.
 399          */
 400         if (inc->inc_flags & INC_ISIPV6)
 401                 hash = HOSTCACHE_HASH6(&inc->inc6_faddr);
 402         else
 403                 hash = HOSTCACHE_HASH(&inc->inc_faddr);
 404
 405         hc_head = &V_tcp_hostcache.hashbase[hash];
 406
 407         /*
 408          * Acquire lock for this bucket row; we release the lock if we don't
 409          * find an entry, otherwise the caller has to unlock after he is
 410          * done.
 411          */
 412         THC_LOCK(hc_head);
 413
 414         /*
 415          * If the bucket limit is reached, reuse the least-used element.
 416          */
 417         if (hc_head->hch_length >= V_tcp_hostcache.bucket_limit ||
 418             atomic_load_int(&V_tcp_hostcache.cache_count) >= V_tcp_hostcache.cache_limit) {
 419                 hc_entry = TAILQ_LAST(&hc_head->hch_bucket, hc_qhead);
 420                 /*
 421                  * At first we were dropping the last element, just to
 422                  * reacquire it in the next two lines again, which isn't very
 423                  * efficient.  Instead just reuse the least used element.
 424                  * We may drop something that is still "in-use" but we can be
 425                  * "lossy".
 426                  * Just give up if this bucket row is empty and we don't have
 427                  * anything to replace.
 428                  */
 429                 if (hc_entry == NULL) {
 430                         THC_UNLOCK(hc_head);
 431                         return (NULL);
 432                 }
 433                 TAILQ_REMOVE(&hc_head->hch_bucket, hc_entry, rmx_q);
 434                 KASSERT(V_tcp_hostcache.hashbase[hash].hch_length > 0 &&
 435                     V_tcp_hostcache.hashbase[hash].hch_length <=
 436                     V_tcp_hostcache.bucket_limit,
 437                     ("tcp_hostcache: bucket length range violated at %u: %u",
 438                     hash, V_tcp_hostcache.hashbase[hash].hch_length));
 439                 V_tcp_hostcache.hashbase[hash].hch_length--;
 440                 atomic_subtract_int(&V_tcp_hostcache.cache_count, 1);
 441                 TCPSTAT_INC(tcps_hc_bucketoverflow);
 442 #if 0
 443                 uma_zfree(V_tcp_hostcache.zone, hc_entry);
 444 #endif
 445         } else {
 446                 /*
 447                  * Allocate a new entry, or balk if not possible.
 448                  */
 449                 hc_entry = uma_zalloc(V_tcp_hostcache.zone, M_NOWAIT);
 450                 if (hc_entry == NULL) {
 451                         THC_UNLOCK(hc_head);
 452                         return (NULL);
 453                 }
 454         }
 455
 456         /*
 457          * Initialize basic information of hostcache entry.
 458          */
 459         bzero(hc_entry, sizeof(*hc_entry));
 460         if (inc->inc_flags & INC_ISIPV6) {
 461                 hc_entry->ip6 = inc->inc6_faddr;
 462                 hc_entry->ip6_zoneid = inc->inc6_zoneid;
 463         } else
 464                 hc_entry->ip4 = inc->inc_faddr;
 465         hc_entry->rmx_head = hc_head;
 466         hc_entry->rmx_expire = V_tcp_hostcache.expire;
 467
 468         /*
 469          * Put it upfront.
 470          */
 471         TAILQ_INSERT_HEAD(&hc_head->hch_bucket, hc_entry, rmx_q);
 472         V_tcp_hostcache.hashbase[hash].hch_length++;
 473         KASSERT(V_tcp_hostcache.hashbase[hash].hch_length <=
 474             V_tcp_hostcache.bucket_limit,
 475             ("tcp_hostcache: bucket length too high at %u: %u",
 476             hash, V_tcp_hostcache.hashbase[hash].hch_length));
 477         atomic_add_int(&V_tcp_hostcache.cache_count, 1);
 478         TCPSTAT_INC(tcps_hc_added);
 479
 480         return (hc_entry);
 481 }
 482
 483 /*
 484  * External function: look up an entry in the hostcache and fill out the
 485  * supplied TCP metrics structure.  Fills in NULL when no entry was found or
 486  * a value is not set.
 487  */
 488 void
 489 tcp_hc_get(struct in_conninfo *inc, struct hc_metrics_lite *hc_metrics_lite)
 490 {
 491         struct hc_metrics *hc_entry;
 492
 493         if (!V_tcp_use_hostcache) {
 494                 bzero(hc_metrics_lite, sizeof(*hc_metrics_lite));
 495                 return;
 496         }
 497
 498         /*
 499          * Find the right bucket.
 500          */
 501         hc_entry = tcp_hc_lookup(inc, false);
 502
 503         /*
 504          * If we don't have an existing object.
 505          */
 506         if (hc_entry == NULL) {
 507                 bzero(hc_metrics_lite, sizeof(*hc_metrics_lite));
 508                 return;
 509         }
 510
 511         hc_metrics_lite->rmx_mtu = hc_entry->rmx_mtu;
 512         hc_metrics_lite->rmx_ssthresh = hc_entry->rmx_ssthresh;
 513         hc_metrics_lite->rmx_rtt = hc_entry->rmx_rtt;
 514         hc_metrics_lite->rmx_rttvar = hc_entry->rmx_rttvar;
 515         hc_metrics_lite->rmx_cwnd = hc_entry->rmx_cwnd;
 516         hc_metrics_lite->rmx_sendpipe = hc_entry->rmx_sendpipe;
 517         hc_metrics_lite->rmx_recvpipe = hc_entry->rmx_recvpipe;
 518
 519         /*
 520          * Unlock bucket row.
 521          */
 522         THC_UNLOCK(hc_entry->rmx_head);
 523 }
 524
 525 /*
 526  * External function: look up an entry in the hostcache and return the
 527  * discovered path MTU.  Returns 0 if no entry is found or value is not
 528  * set.
 529  */
 530 uint32_t
 531 tcp_hc_getmtu(struct in_conninfo *inc)
 532 {
 533         struct hc_metrics *hc_entry;
 534         uint32_t mtu;
 535
 536         if (!V_tcp_use_hostcache)
 537                 return (0);
 538
 539         hc_entry = tcp_hc_lookup(inc, false);
 540         if (hc_entry == NULL) {
 541                 return (0);
 542         }
 543
 544         mtu = hc_entry->rmx_mtu;
 545         THC_UNLOCK(hc_entry->rmx_head);
 546         return (mtu);
 547 }
 548
 549 /*
 550  * External function: update the MTU value of an entry in the hostcache.
 551  * Creates a new entry if none was found.
 552  */
 553 void
 554 tcp_hc_updatemtu(struct in_conninfo *inc, uint32_t mtu)
 555 {
 556         struct hc_metrics_lite hcml = { .rmx_mtu = mtu };
 557
 558         return (tcp_hc_update(inc, &hcml));
 559 }
 560
 561 /*
 562  * External function: update the TCP metrics of an entry in the hostcache.
 563  * Creates a new entry if none was found.
 564  */
 565 void
 566 tcp_hc_update(struct in_conninfo *inc, struct hc_metrics_lite *hcml)
 567 {
 568         struct hc_metrics *hc_entry;
 569
 570         if (!V_tcp_use_hostcache)
 571                 return;
 572
 573         hc_entry = tcp_hc_lookup(inc, true);
 574         if (hc_entry == NULL) {
 575                 hc_entry = tcp_hc_insert(inc);
 576                 if (hc_entry == NULL)
 577                         return;
 578         }
 579
 580         if (hcml->rmx_mtu != 0) {
 581                 hc_entry->rmx_mtu = hcml->rmx_mtu;
 582         }
 583         if (hcml->rmx_rtt != 0) {
 584                 if (hc_entry->rmx_rtt == 0)
 585                         hc_entry->rmx_rtt = hcml->rmx_rtt;
 586                 else
 587                         hc_entry->rmx_rtt = ((uint64_t)hc_entry->rmx_rtt +
 588                             (uint64_t)hcml->rmx_rtt) / 2;
 589                 TCPSTAT_INC(tcps_cachedrtt);
 590         }
 591         if (hcml->rmx_rttvar != 0) {
 592                 if (hc_entry->rmx_rttvar == 0)
 593                         hc_entry->rmx_rttvar = hcml->rmx_rttvar;
 594                 else
 595                         hc_entry->rmx_rttvar = ((uint64_t)hc_entry->rmx_rttvar +
 596                             (uint64_t)hcml->rmx_rttvar) / 2;
 597                 TCPSTAT_INC(tcps_cachedrttvar);
 598         }
 599         if (hcml->rmx_ssthresh != 0) {
 600                 if (hc_entry->rmx_ssthresh == 0)
 601                         hc_entry->rmx_ssthresh = hcml->rmx_ssthresh;
 602                 else
 603                         hc_entry->rmx_ssthresh =
 604                             (hc_entry->rmx_ssthresh + hcml->rmx_ssthresh) / 2;
 605                 TCPSTAT_INC(tcps_cachedssthresh);
 606         }
 607         if (hcml->rmx_cwnd != 0) {
 608                 if (hc_entry->rmx_cwnd == 0)
 609                         hc_entry->rmx_cwnd = hcml->rmx_cwnd;
 610                 else
 611                         hc_entry->rmx_cwnd = ((uint64_t)hc_entry->rmx_cwnd +
 612                             (uint64_t)hcml->rmx_cwnd) / 2;
 613                 /* TCPSTAT_INC(tcps_cachedcwnd); */
 614         }
 615         if (hcml->rmx_sendpipe != 0) {
 616                 if (hc_entry->rmx_sendpipe == 0)
 617                         hc_entry->rmx_sendpipe = hcml->rmx_sendpipe;
 618                 else
 619                         hc_entry->rmx_sendpipe =
 620                             ((uint64_t)hc_entry->rmx_sendpipe +
 621                             (uint64_t)hcml->rmx_sendpipe) /2;
 622                 /* TCPSTAT_INC(tcps_cachedsendpipe); */
 623         }
 624         if (hcml->rmx_recvpipe != 0) {
 625                 if (hc_entry->rmx_recvpipe == 0)
 626                         hc_entry->rmx_recvpipe = hcml->rmx_recvpipe;
 627                 else
 628                         hc_entry->rmx_recvpipe =
 629                             ((uint64_t)hc_entry->rmx_recvpipe +
 630                             (uint64_t)hcml->rmx_recvpipe) /2;
 631                 /* TCPSTAT_INC(tcps_cachedrecvpipe); */
 632         }
 633
 634         TAILQ_REMOVE(&hc_entry->rmx_head->hch_bucket, hc_entry, rmx_q);
 635         TAILQ_INSERT_HEAD(&hc_entry->rmx_head->hch_bucket, hc_entry, rmx_q);
 636         THC_UNLOCK(hc_entry->rmx_head);
 637 }
 638
 639 /*
 640  * Sysctl function: prints the list and values of all hostcache entries in
 641  * unsorted order.
 642  */
 643 static int
 644 sysctl_tcp_hc_list(SYSCTL_HANDLER_ARGS)
 645 {
 646         const int linesize = 128;
 647         struct sbuf sb;
 648         int i, error, len;
 649         struct hc_metrics *hc_entry;
 650         char ip4buf[INET_ADDRSTRLEN];
 651 #ifdef INET6
 652         char ip6buf[INET6_ADDRSTRLEN];
 653 #endif
 654
 655         if (jailed_without_vnet(curthread->td_ucred) != 0)
 656                 return (EPERM);
 657
 658         /* Optimize Buffer length query by sbin/sysctl */
 659         if (req->oldptr == NULL) {
 660                 len = (atomic_load_int(&V_tcp_hostcache.cache_count) + 1) *
 661                         linesize;
 662                 return (SYSCTL_OUT(req, NULL, len));
 663         }
 664
 665         error = sysctl_wire_old_buffer(req, 0);
 666         if (error != 0) {
 667                 return(error);
 668         }
 669
 670         /* Use a buffer sized for one full bucket */
 671         sbuf_new_for_sysctl(&sb, NULL, V_tcp_hostcache.bucket_limit *
 672                 linesize, req);
 673
 674         sbuf_printf(&sb,
 675                 "\nIP address        MTU  SSTRESH      RTT   RTTVAR "
 676                 "    CWND SENDPIPE RECVPIPE "
 677 #ifdef  TCP_HC_COUNTERS
 678                 "HITS  UPD  "
 679 #endif
 680                 "EXP\n");
 681         sbuf_drain(&sb);
 682
 683 #define msec(u) (((u) + 500) / 1000)
 684         for (i = 0; i < V_tcp_hostcache.hashsize; i++) {
 685                 THC_LOCK(&V_tcp_hostcache.hashbase[i]);
 686                 TAILQ_FOREACH(hc_entry, &V_tcp_hostcache.hashbase[i].hch_bucket,
 687                     rmx_q) {
 688                         sbuf_printf(&sb,
 689                             "%-15s %5u %8u %6lums %6lums %8u %8u %8u "
 690 #ifdef  TCP_HC_COUNTERS
 691                             "%4lu %4lu "
 692 #endif
 693                             "%4i\n",
 694                             hc_entry->ip4.s_addr ?
 695                                 inet_ntoa_r(hc_entry->ip4, ip4buf) :
 696 #ifdef INET6
 697                                 ip6_sprintf(ip6buf, &hc_entry->ip6),
 698 #else
 699                                 "IPv6?",
 700 #endif
 701                             hc_entry->rmx_mtu,
 702                             hc_entry->rmx_ssthresh,
 703                             msec((u_long)hc_entry->rmx_rtt *
 704                                 (RTM_RTTUNIT / (hz * TCP_RTT_SCALE))),
 705                             msec((u_long)hc_entry->rmx_rttvar *
 706                                 (RTM_RTTUNIT / (hz * TCP_RTTVAR_SCALE))),
 707                             hc_entry->rmx_cwnd,
 708                             hc_entry->rmx_sendpipe,
 709                             hc_entry->rmx_recvpipe,
 710 #ifdef  TCP_HC_COUNTERS
 711                             hc_entry->rmx_hits,
 712                             hc_entry->rmx_updates,
 713 #endif
 714                             hc_entry->rmx_expire);
 715                 }
 716                 THC_UNLOCK(&V_tcp_hostcache.hashbase[i]);
 717                 sbuf_drain(&sb);
 718         }
 719 #undef msec
 720         error = sbuf_finish(&sb);
 721         sbuf_delete(&sb);
 722         return(error);
 723 }
 724
 725 /*
 726  * Sysctl function: prints a histogram of the hostcache hashbucket
 727  * utilization.
 728  */
 729 static int
 730 sysctl_tcp_hc_histo(SYSCTL_HANDLER_ARGS)
 731 {
 732         const int linesize = 50;
 733         struct sbuf sb;
 734         int i, error;
 735         int *histo;
 736         u_int hch_length;
 737
 738         if (jailed_without_vnet(curthread->td_ucred) != 0)
 739                 return (EPERM);
 740
 741         histo = (int *)malloc(sizeof(int) * (V_tcp_hostcache.bucket_limit + 1),
 742                         M_TEMP, M_NOWAIT|M_ZERO);
 743         if (histo == NULL)
 744                 return(ENOMEM);
 745
 746         for (i = 0; i < V_tcp_hostcache.hashsize; i++) {
 747                 hch_length = V_tcp_hostcache.hashbase[i].hch_length;
 748                 KASSERT(hch_length <= V_tcp_hostcache.bucket_limit,
 749                     ("tcp_hostcache: bucket limit exceeded at %u: %u",
 750                     i, hch_length));
 751                 histo[hch_length]++;
 752         }
 753
 754         /* Use a buffer for 16 lines */
 755         sbuf_new_for_sysctl(&sb, NULL, 16 * linesize, req);
 756
 757         sbuf_printf(&sb, "\nLength\tCount\n");
 758         for (i = 0; i <= V_tcp_hostcache.bucket_limit; i++) {
 759                 sbuf_printf(&sb, "%u\t%u\n", i, histo[i]);
 760         }
 761         error = sbuf_finish(&sb);
 762         sbuf_delete(&sb);
 763         free(histo, M_TEMP);
 764         return(error);
 765 }
 766
 767 /*
 768  * Caller has to make sure the curvnet is set properly.
 769  */
 770 static void
 771 tcp_hc_purge_internal(int all)
 772 {
 773         struct hc_metrics *hc_entry, *hc_next;
 774         int i;
 775
 776         for (i = 0; i < V_tcp_hostcache.hashsize; i++) {
 777                 THC_LOCK(&V_tcp_hostcache.hashbase[i]);
 778                 TAILQ_FOREACH_SAFE(hc_entry,
 779                     &V_tcp_hostcache.hashbase[i].hch_bucket, rmx_q, hc_next) {
 780                         KASSERT(V_tcp_hostcache.hashbase[i].hch_length > 0 &&
 781                             V_tcp_hostcache.hashbase[i].hch_length <=
 782                             V_tcp_hostcache.bucket_limit, ("tcp_hostcache: "
 783                             "bucket length out of range at %u: %u",
 784                             i, V_tcp_hostcache.hashbase[i].hch_length));
 785                         if (all || hc_entry->rmx_expire <= 0) {
 786                                 TAILQ_REMOVE(
 787                                     &V_tcp_hostcache.hashbase[i].hch_bucket,
 788                                     hc_entry, rmx_q);
 789                                 uma_zfree(V_tcp_hostcache.zone, hc_entry);
 790                                 V_tcp_hostcache.hashbase[i].hch_length--;
 791                                 atomic_subtract_int(&V_tcp_hostcache.cache_count, 1);
 792                         } else
 793                                 hc_entry->rmx_expire -= V_tcp_hostcache.prune;
 794                 }
 795                 THC_UNLOCK(&V_tcp_hostcache.hashbase[i]);
 796         }
 797 }
 798
 799 /*
 800  * Expire and purge (old|all) entries in the tcp_hostcache.  Runs
 801  * periodically from the callout.
 802  */
 803 static void
 804 tcp_hc_purge(void *arg)
 805 {
 806         CURVNET_SET((struct vnet *) arg);
 807         int all = 0;
 808
 809         if (V_tcp_hostcache.purgeall) {
 810                 if (V_tcp_hostcache.purgeall == 2)
 811                         V_tcp_hostcache.hashsalt = arc4random();
 812                 all = 1;
 813                 V_tcp_hostcache.purgeall = 0;
 814         }
 815
 816         tcp_hc_purge_internal(all);
 817
 818         callout_reset(&V_tcp_hc_callout, V_tcp_hostcache.prune * hz,
 819             tcp_hc_purge, arg);
 820         CURVNET_RESTORE();
 821 }
 822
 823 /*
 824  * Expire and purge all entries in hostcache immediately.
 825  */
 826 static int
 827 sysctl_tcp_hc_purgenow(SYSCTL_HANDLER_ARGS)
 828 {
 829         int error, val;
 830
 831         val = 0;
 832         error = sysctl_handle_int(oidp, &val, 0, req);
 833         if (error || !req->newptr)
 834                 return (error);
 835
 836         if (val == 2)
 837                 V_tcp_hostcache.hashsalt = arc4random();
 838         tcp_hc_purge_internal(1);
 839
 840         callout_reset(&V_tcp_hc_callout, V_tcp_hostcache.prune * hz,
 841             tcp_hc_purge, curvnet);
 842
 843         return (0);
 844 }