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/if.h>
  87 #include <net/if_var.h>
  88 #include <net/route.h>
  89 #include <net/vnet.h>
  90
  91 #include <netinet/in.h>
  92 #include <netinet/in_systm.h>
  93 #include <netinet/ip.h>
  94 #include <netinet/in_var.h>
  95 #include <netinet/in_pcb.h>
  96 #include <netinet/ip_var.h>
  97 #ifdef INET6
  98 #include <netinet/ip6.h>
  99 #include <netinet6/ip6_var.h>
 100 #endif
 101 #include <netinet/tcp.h>
 102 #include <netinet/tcp_var.h>
 103 #include <netinet/tcp_hostcache.h>
 104 #ifdef INET6
 105 #include <netinet6/tcp6_var.h>
 106 #endif
 107
 108 #include <vm/uma.h>
 109
 110 /* Arbitrary values */
 111 #define TCP_HOSTCACHE_HASHSIZE          512
 112 #define TCP_HOSTCACHE_BUCKETLIMIT       30
 113 #define TCP_HOSTCACHE_EXPIRE            60*60   /* one hour */
 114 #define TCP_HOSTCACHE_PRUNE             5*60    /* every 5 minutes */
 115
 116 VNET_DEFINE_STATIC(struct tcp_hostcache, tcp_hostcache);
 117 #define V_tcp_hostcache         VNET(tcp_hostcache)
 118
 119 VNET_DEFINE_STATIC(struct callout, tcp_hc_callout);
 120 #define V_tcp_hc_callout        VNET(tcp_hc_callout)
 121
 122 static struct hc_metrics *tcp_hc_lookup(struct in_conninfo *);
 123 static struct hc_metrics *tcp_hc_insert(struct in_conninfo *);
 124 static int sysctl_tcp_hc_list(SYSCTL_HANDLER_ARGS);
 125 static int sysctl_tcp_hc_histo(SYSCTL_HANDLER_ARGS);
 126 static int sysctl_tcp_hc_purgenow(SYSCTL_HANDLER_ARGS);
 127 static void tcp_hc_purge_internal(int);
 128 static void tcp_hc_purge(void *);
 129
 130 static SYSCTL_NODE(_net_inet_tcp, OID_AUTO, hostcache,
 131     CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
 132     "TCP Host cache");
 133
 134 VNET_DEFINE(int, tcp_use_hostcache) = 1;
 135 #define V_tcp_use_hostcache  VNET(tcp_use_hostcache)
 136 SYSCTL_INT(_net_inet_tcp_hostcache, OID_AUTO, enable, CTLFLAG_VNET | CTLFLAG_RW,
 137     &VNET_NAME(tcp_use_hostcache), 0,
 138     "Enable the TCP hostcache");
 139
 140 SYSCTL_UINT(_net_inet_tcp_hostcache, OID_AUTO, cachelimit, CTLFLAG_VNET | CTLFLAG_RDTUN,
 141     &VNET_NAME(tcp_hostcache.cache_limit), 0,
 142     "Overall entry limit for hostcache");
 143
 144 SYSCTL_UINT(_net_inet_tcp_hostcache, OID_AUTO, hashsize, CTLFLAG_VNET | CTLFLAG_RDTUN,
 145     &VNET_NAME(tcp_hostcache.hashsize), 0,
 146     "Size of TCP hostcache hashtable");
 147
 148 SYSCTL_UINT(_net_inet_tcp_hostcache, OID_AUTO, bucketlimit,
 149     CTLFLAG_VNET | CTLFLAG_RDTUN, &VNET_NAME(tcp_hostcache.bucket_limit), 0,
 150     "Per-bucket hash limit for hostcache");
 151
 152 SYSCTL_UINT(_net_inet_tcp_hostcache, OID_AUTO, count, CTLFLAG_VNET | CTLFLAG_RD,
 153      &VNET_NAME(tcp_hostcache.cache_count), 0,
 154     "Current number of entries in hostcache");
 155
 156 SYSCTL_INT(_net_inet_tcp_hostcache, OID_AUTO, expire, CTLFLAG_VNET | CTLFLAG_RW,
 157     &VNET_NAME(tcp_hostcache.expire), 0,
 158     "Expire time of TCP hostcache entries");
 159
 160 SYSCTL_INT(_net_inet_tcp_hostcache, OID_AUTO, prune, CTLFLAG_VNET | CTLFLAG_RW,
 161     &VNET_NAME(tcp_hostcache.prune), 0,
 162     "Time between purge runs");
 163
 164 SYSCTL_INT(_net_inet_tcp_hostcache, OID_AUTO, purge, CTLFLAG_VNET | CTLFLAG_RW,
 165     &VNET_NAME(tcp_hostcache.purgeall), 0,
 166     "Expire all entries on next purge run");
 167
 168 SYSCTL_PROC(_net_inet_tcp_hostcache, OID_AUTO, list,
 169     CTLTYPE_STRING | CTLFLAG_RD | CTLFLAG_SKIP | CTLFLAG_MPSAFE,
 170     0, 0, sysctl_tcp_hc_list, "A",
 171     "List of all hostcache entries");
 172
 173 SYSCTL_PROC(_net_inet_tcp_hostcache, OID_AUTO, histo,
 174     CTLTYPE_STRING | CTLFLAG_RD | CTLFLAG_SKIP | CTLFLAG_MPSAFE,
 175     0, 0, sysctl_tcp_hc_histo, "A",
 176     "Print a histogram of hostcache hashbucket utilization");
 177
 178 SYSCTL_PROC(_net_inet_tcp_hostcache, OID_AUTO, purgenow,
 179     CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_MPSAFE,
 180     NULL, 0, sysctl_tcp_hc_purgenow, "I",
 181     "Immediately purge all entries");
 182
 183 static MALLOC_DEFINE(M_HOSTCACHE, "hostcache", "TCP hostcache");
 184
 185 /* Use jenkins_hash32(), as in other parts of the tcp stack */
 186 #define HOSTCACHE_HASH(ip) \
 187         (jenkins_hash32((uint32_t *)(ip), 1, V_tcp_hostcache.hashsalt) & \
 188          V_tcp_hostcache.hashmask)
 189
 190 #define HOSTCACHE_HASH6(ip6)                            \
 191         (jenkins_hash32((uint32_t *)&((ip6)->s6_addr32[0]), 4, \
 192          V_tcp_hostcache.hashsalt) & \
 193          V_tcp_hostcache.hashmask)
 194
 195 #define THC_LOCK(lp)            mtx_lock(lp)
 196 #define THC_UNLOCK(lp)          mtx_unlock(lp)
 197
 198 void
 199 tcp_hc_init(void)
 200 {
 201         u_int cache_limit;
 202         int i;
 203
 204         /*
 205          * Initialize hostcache structures.
 206          */
 207         atomic_store_int(&V_tcp_hostcache.cache_count, 0);
 208         V_tcp_hostcache.hashsize = TCP_HOSTCACHE_HASHSIZE;
 209         V_tcp_hostcache.bucket_limit = TCP_HOSTCACHE_BUCKETLIMIT;
 210         V_tcp_hostcache.expire = TCP_HOSTCACHE_EXPIRE;
 211         V_tcp_hostcache.prune = TCP_HOSTCACHE_PRUNE;
 212         V_tcp_hostcache.hashsalt = arc4random();
 213
 214         TUNABLE_INT_FETCH("net.inet.tcp.hostcache.hashsize",
 215             &V_tcp_hostcache.hashsize);
 216         if (!powerof2(V_tcp_hostcache.hashsize)) {
 217                 printf("WARNING: hostcache hash size is not a power of 2.\n");
 218                 V_tcp_hostcache.hashsize = TCP_HOSTCACHE_HASHSIZE; /* default */
 219         }
 220         V_tcp_hostcache.hashmask = V_tcp_hostcache.hashsize - 1;
 221
 222         TUNABLE_INT_FETCH("net.inet.tcp.hostcache.bucketlimit",
 223             &V_tcp_hostcache.bucket_limit);
 224
 225         cache_limit = V_tcp_hostcache.hashsize * V_tcp_hostcache.bucket_limit;
 226         V_tcp_hostcache.cache_limit = cache_limit;
 227         TUNABLE_INT_FETCH("net.inet.tcp.hostcache.cachelimit",
 228             &V_tcp_hostcache.cache_limit);
 229         if (V_tcp_hostcache.cache_limit > cache_limit)
 230                 V_tcp_hostcache.cache_limit = cache_limit;
 231
 232         /*
 233          * Allocate the hash table.
 234          */
 235         V_tcp_hostcache.hashbase = (struct hc_head *)
 236             malloc(V_tcp_hostcache.hashsize * sizeof(struct hc_head),
 237                    M_HOSTCACHE, M_WAITOK | M_ZERO);
 238
 239         /*
 240          * Initialize the hash buckets.
 241          */
 242         for (i = 0; i < V_tcp_hostcache.hashsize; i++) {
 243                 TAILQ_INIT(&V_tcp_hostcache.hashbase[i].hch_bucket);
 244                 V_tcp_hostcache.hashbase[i].hch_length = 0;
 245                 mtx_init(&V_tcp_hostcache.hashbase[i].hch_mtx, "tcp_hc_entry",
 246                           NULL, MTX_DEF);
 247         }
 248
 249         /*
 250          * Allocate the hostcache entries.
 251          */
 252         V_tcp_hostcache.zone =
 253             uma_zcreate("hostcache", sizeof(struct hc_metrics),
 254             NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, 0);
 255         uma_zone_set_max(V_tcp_hostcache.zone, V_tcp_hostcache.cache_limit);
 256
 257         /*
 258          * Set up periodic cache cleanup.
 259          */
 260         callout_init(&V_tcp_hc_callout, 1);
 261         callout_reset(&V_tcp_hc_callout, V_tcp_hostcache.prune * hz,
 262             tcp_hc_purge, curvnet);
 263 }
 264
 265 #ifdef VIMAGE
 266 void
 267 tcp_hc_destroy(void)
 268 {
 269         int i;
 270
 271         callout_drain(&V_tcp_hc_callout);
 272
 273         /* Purge all hc entries. */
 274         tcp_hc_purge_internal(1);
 275
 276         /* Free the uma zone and the allocated hash table. */
 277         uma_zdestroy(V_tcp_hostcache.zone);
 278
 279         for (i = 0; i < V_tcp_hostcache.hashsize; i++)
 280                 mtx_destroy(&V_tcp_hostcache.hashbase[i].hch_mtx);
 281         free(V_tcp_hostcache.hashbase, M_HOSTCACHE);
 282 }
 283 #endif
 284
 285 /*
 286  * Internal function: look up an entry in the hostcache or return NULL.
 287  *
 288  * If an entry has been returned, the caller becomes responsible for
 289  * unlocking the bucket row after he is done reading/modifying the entry.
 290  */
 291 static struct hc_metrics *
 292 tcp_hc_lookup(struct in_conninfo *inc)
 293 {
 294         int hash;
 295         struct hc_head *hc_head;
 296         struct hc_metrics *hc_entry;
 297
 298         if (!V_tcp_use_hostcache)
 299                 return NULL;
 300
 301         KASSERT(inc != NULL, ("tcp_hc_lookup with NULL in_conninfo pointer"));
 302
 303         /*
 304          * Hash the foreign ip address.
 305          */
 306         if (inc->inc_flags & INC_ISIPV6)
 307                 hash = HOSTCACHE_HASH6(&inc->inc6_faddr);
 308         else
 309                 hash = HOSTCACHE_HASH(&inc->inc_faddr);
 310
 311         hc_head = &V_tcp_hostcache.hashbase[hash];
 312
 313         /*
 314          * Acquire lock for this bucket row; we release the lock if we don't
 315          * find an entry, otherwise the caller has to unlock after he is
 316          * done.
 317          */
 318         THC_LOCK(&hc_head->hch_mtx);
 319
 320         /*
 321          * Iterate through entries in bucket row looking for a match.
 322          */
 323         TAILQ_FOREACH(hc_entry, &hc_head->hch_bucket, rmx_q) {
 324                 if (inc->inc_flags & INC_ISIPV6) {
 325                         /* XXX: check ip6_zoneid */
 326                         if (memcmp(&inc->inc6_faddr, &hc_entry->ip6,
 327                             sizeof(inc->inc6_faddr)) == 0)
 328                                 return hc_entry;
 329                 } else {
 330                         if (memcmp(&inc->inc_faddr, &hc_entry->ip4,
 331                             sizeof(inc->inc_faddr)) == 0)
 332                                 return hc_entry;
 333                 }
 334         }
 335
 336         /*
 337          * We were unsuccessful and didn't find anything.
 338          */
 339         THC_UNLOCK(&hc_head->hch_mtx);
 340         return NULL;
 341 }
 342
 343 /*
 344  * Internal function: insert an entry into the hostcache or return NULL if
 345  * unable to allocate a new one.
 346  *
 347  * If an entry has been returned, the caller becomes responsible for
 348  * unlocking the bucket row after he is done reading/modifying the entry.
 349  */
 350 static struct hc_metrics *
 351 tcp_hc_insert(struct in_conninfo *inc)
 352 {
 353         int hash;
 354         struct hc_head *hc_head;
 355         struct hc_metrics *hc_entry;
 356
 357         if (!V_tcp_use_hostcache)
 358                 return NULL;
 359
 360         KASSERT(inc != NULL, ("tcp_hc_insert with NULL in_conninfo pointer"));
 361
 362         /*
 363          * Hash the foreign ip address.
 364          */
 365         if (inc->inc_flags & INC_ISIPV6)
 366                 hash = HOSTCACHE_HASH6(&inc->inc6_faddr);
 367         else
 368                 hash = HOSTCACHE_HASH(&inc->inc_faddr);
 369
 370         hc_head = &V_tcp_hostcache.hashbase[hash];
 371
 372         /*
 373          * Acquire lock for this bucket row; we release the lock if we don't
 374          * find an entry, otherwise the caller has to unlock after he is
 375          * done.
 376          */
 377         THC_LOCK(&hc_head->hch_mtx);
 378
 379         /*
 380          * If the bucket limit is reached, reuse the least-used element.
 381          */
 382         if (hc_head->hch_length >= V_tcp_hostcache.bucket_limit ||
 383             atomic_load_int(&V_tcp_hostcache.cache_count) >= V_tcp_hostcache.cache_limit) {
 384                 hc_entry = TAILQ_LAST(&hc_head->hch_bucket, hc_qhead);
 385                 /*
 386                  * At first we were dropping the last element, just to
 387                  * reacquire it in the next two lines again, which isn't very
 388                  * efficient.  Instead just reuse the least used element.
 389                  * We may drop something that is still "in-use" but we can be
 390                  * "lossy".
 391                  * Just give up if this bucket row is empty and we don't have
 392                  * anything to replace.
 393                  */
 394                 if (hc_entry == NULL) {
 395                         THC_UNLOCK(&hc_head->hch_mtx);
 396                         return NULL;
 397                 }
 398                 TAILQ_REMOVE(&hc_head->hch_bucket, hc_entry, rmx_q);
 399                 KASSERT(V_tcp_hostcache.hashbase[hash].hch_length > 0 &&
 400                         V_tcp_hostcache.hashbase[hash].hch_length <=
 401                         V_tcp_hostcache.bucket_limit,
 402                         ("tcp_hostcache: bucket length range violated at %u: %u",
 403                         hash, V_tcp_hostcache.hashbase[hash].hch_length));
 404                 V_tcp_hostcache.hashbase[hash].hch_length--;
 405                 atomic_subtract_int(&V_tcp_hostcache.cache_count, 1);
 406                 TCPSTAT_INC(tcps_hc_bucketoverflow);
 407 #if 0
 408                 uma_zfree(V_tcp_hostcache.zone, hc_entry);
 409 #endif
 410         } else {
 411                 /*
 412                  * Allocate a new entry, or balk if not possible.
 413                  */
 414                 hc_entry = uma_zalloc(V_tcp_hostcache.zone, M_NOWAIT);
 415                 if (hc_entry == NULL) {
 416                         THC_UNLOCK(&hc_head->hch_mtx);
 417                         return NULL;
 418                 }
 419         }
 420
 421         /*
 422          * Initialize basic information of hostcache entry.
 423          */
 424         bzero(hc_entry, sizeof(*hc_entry));
 425         if (inc->inc_flags & INC_ISIPV6) {
 426                 hc_entry->ip6 = inc->inc6_faddr;
 427                 hc_entry->ip6_zoneid = inc->inc6_zoneid;
 428         } else
 429                 hc_entry->ip4 = inc->inc_faddr;
 430         hc_entry->rmx_head = hc_head;
 431         hc_entry->rmx_expire = V_tcp_hostcache.expire;
 432
 433         /*
 434          * Put it upfront.
 435          */
 436         TAILQ_INSERT_HEAD(&hc_head->hch_bucket, hc_entry, rmx_q);
 437         V_tcp_hostcache.hashbase[hash].hch_length++;
 438         KASSERT(V_tcp_hostcache.hashbase[hash].hch_length <
 439                 V_tcp_hostcache.bucket_limit,
 440                 ("tcp_hostcache: bucket length too high at %u: %u",
 441                 hash, V_tcp_hostcache.hashbase[hash].hch_length));
 442         atomic_add_int(&V_tcp_hostcache.cache_count, 1);
 443         TCPSTAT_INC(tcps_hc_added);
 444
 445         return hc_entry;
 446 }
 447
 448 /*
 449  * External function: look up an entry in the hostcache and fill out the
 450  * supplied TCP metrics structure.  Fills in NULL when no entry was found or
 451  * a value is not set.
 452  */
 453 void
 454 tcp_hc_get(struct in_conninfo *inc, struct hc_metrics_lite *hc_metrics_lite)
 455 {
 456         struct hc_metrics *hc_entry;
 457
 458         if (!V_tcp_use_hostcache) {
 459                 bzero(hc_metrics_lite, sizeof(*hc_metrics_lite));
 460                 return;
 461         }
 462
 463         /*
 464          * Find the right bucket.
 465          */
 466         hc_entry = tcp_hc_lookup(inc);
 467
 468         /*
 469          * If we don't have an existing object.
 470          */
 471         if (hc_entry == NULL) {
 472                 bzero(hc_metrics_lite, sizeof(*hc_metrics_lite));
 473                 return;
 474         }
 475         hc_entry->rmx_hits++;
 476         hc_entry->rmx_expire = V_tcp_hostcache.expire; /* start over again */
 477
 478         hc_metrics_lite->rmx_mtu = hc_entry->rmx_mtu;
 479         hc_metrics_lite->rmx_ssthresh = hc_entry->rmx_ssthresh;
 480         hc_metrics_lite->rmx_rtt = hc_entry->rmx_rtt;
 481         hc_metrics_lite->rmx_rttvar = hc_entry->rmx_rttvar;
 482         hc_metrics_lite->rmx_cwnd = hc_entry->rmx_cwnd;
 483         hc_metrics_lite->rmx_sendpipe = hc_entry->rmx_sendpipe;
 484         hc_metrics_lite->rmx_recvpipe = hc_entry->rmx_recvpipe;
 485
 486         /*
 487          * Unlock bucket row.
 488          */
 489         THC_UNLOCK(&hc_entry->rmx_head->hch_mtx);
 490 }
 491
 492 /*
 493  * External function: look up an entry in the hostcache and return the
 494  * discovered path MTU.  Returns 0 if no entry is found or value is not
 495  * set.
 496  */
 497 uint32_t
 498 tcp_hc_getmtu(struct in_conninfo *inc)
 499 {
 500         struct hc_metrics *hc_entry;
 501         uint32_t mtu;
 502
 503         if (!V_tcp_use_hostcache)
 504                 return 0;
 505
 506         hc_entry = tcp_hc_lookup(inc);
 507         if (hc_entry == NULL) {
 508                 return 0;
 509         }
 510         hc_entry->rmx_hits++;
 511         hc_entry->rmx_expire = V_tcp_hostcache.expire; /* start over again */
 512
 513         mtu = hc_entry->rmx_mtu;
 514         THC_UNLOCK(&hc_entry->rmx_head->hch_mtx);
 515         return mtu;
 516 }
 517
 518 /*
 519  * External function: update the MTU value of an entry in the hostcache.
 520  * Creates a new entry if none was found.
 521  */
 522 void
 523 tcp_hc_updatemtu(struct in_conninfo *inc, uint32_t mtu)
 524 {
 525         struct hc_metrics *hc_entry;
 526
 527         if (!V_tcp_use_hostcache)
 528                 return;
 529
 530         /*
 531          * Find the right bucket.
 532          */
 533         hc_entry = tcp_hc_lookup(inc);
 534
 535         /*
 536          * If we don't have an existing object, try to insert a new one.
 537          */
 538         if (hc_entry == NULL) {
 539                 hc_entry = tcp_hc_insert(inc);
 540                 if (hc_entry == NULL)
 541                         return;
 542         }
 543         hc_entry->rmx_updates++;
 544         hc_entry->rmx_expire = V_tcp_hostcache.expire; /* start over again */
 545
 546         hc_entry->rmx_mtu = mtu;
 547
 548         /*
 549          * Put it upfront so we find it faster next time.
 550          */
 551         TAILQ_REMOVE(&hc_entry->rmx_head->hch_bucket, hc_entry, rmx_q);
 552         TAILQ_INSERT_HEAD(&hc_entry->rmx_head->hch_bucket, hc_entry, rmx_q);
 553
 554         /*
 555          * Unlock bucket row.
 556          */
 557         THC_UNLOCK(&hc_entry->rmx_head->hch_mtx);
 558 }
 559
 560 /*
 561  * External function: update the TCP metrics of an entry in the hostcache.
 562  * Creates a new entry if none was found.
 563  */
 564 void
 565 tcp_hc_update(struct in_conninfo *inc, struct hc_metrics_lite *hcml)
 566 {
 567         struct hc_metrics *hc_entry;
 568
 569         if (!V_tcp_use_hostcache)
 570                 return;
 571
 572         hc_entry = tcp_hc_lookup(inc);
 573         if (hc_entry == NULL) {
 574                 hc_entry = tcp_hc_insert(inc);
 575                 if (hc_entry == NULL)
 576                         return;
 577         }
 578         hc_entry->rmx_updates++;
 579         hc_entry->rmx_expire = V_tcp_hostcache.expire; /* start over again */
 580
 581         if (hcml->rmx_rtt != 0) {
 582                 if (hc_entry->rmx_rtt == 0)
 583                         hc_entry->rmx_rtt = hcml->rmx_rtt;
 584                 else
 585                         hc_entry->rmx_rtt = ((uint64_t)hc_entry->rmx_rtt +
 586                             (uint64_t)hcml->rmx_rtt) / 2;
 587                 TCPSTAT_INC(tcps_cachedrtt);
 588         }
 589         if (hcml->rmx_rttvar != 0) {
 590                 if (hc_entry->rmx_rttvar == 0)
 591                         hc_entry->rmx_rttvar = hcml->rmx_rttvar;
 592                 else
 593                         hc_entry->rmx_rttvar = ((uint64_t)hc_entry->rmx_rttvar +
 594                             (uint64_t)hcml->rmx_rttvar) / 2;
 595                 TCPSTAT_INC(tcps_cachedrttvar);
 596         }
 597         if (hcml->rmx_ssthresh != 0) {
 598                 if (hc_entry->rmx_ssthresh == 0)
 599                         hc_entry->rmx_ssthresh = hcml->rmx_ssthresh;
 600                 else
 601                         hc_entry->rmx_ssthresh =
 602                             (hc_entry->rmx_ssthresh + hcml->rmx_ssthresh) / 2;
 603                 TCPSTAT_INC(tcps_cachedssthresh);
 604         }
 605         if (hcml->rmx_cwnd != 0) {
 606                 if (hc_entry->rmx_cwnd == 0)
 607                         hc_entry->rmx_cwnd = hcml->rmx_cwnd;
 608                 else
 609                         hc_entry->rmx_cwnd = ((uint64_t)hc_entry->rmx_cwnd +
 610                             (uint64_t)hcml->rmx_cwnd) / 2;
 611                 /* TCPSTAT_INC(tcps_cachedcwnd); */
 612         }
 613         if (hcml->rmx_sendpipe != 0) {
 614                 if (hc_entry->rmx_sendpipe == 0)
 615                         hc_entry->rmx_sendpipe = hcml->rmx_sendpipe;
 616                 else
 617                         hc_entry->rmx_sendpipe =
 618                             ((uint64_t)hc_entry->rmx_sendpipe +
 619                             (uint64_t)hcml->rmx_sendpipe) /2;
 620                 /* TCPSTAT_INC(tcps_cachedsendpipe); */
 621         }
 622         if (hcml->rmx_recvpipe != 0) {
 623                 if (hc_entry->rmx_recvpipe == 0)
 624                         hc_entry->rmx_recvpipe = hcml->rmx_recvpipe;
 625                 else
 626                         hc_entry->rmx_recvpipe =
 627                             ((uint64_t)hc_entry->rmx_recvpipe +
 628                             (uint64_t)hcml->rmx_recvpipe) /2;
 629                 /* TCPSTAT_INC(tcps_cachedrecvpipe); */
 630         }
 631
 632         TAILQ_REMOVE(&hc_entry->rmx_head->hch_bucket, hc_entry, rmx_q);
 633         TAILQ_INSERT_HEAD(&hc_entry->rmx_head->hch_bucket, hc_entry, rmx_q);
 634         THC_UNLOCK(&hc_entry->rmx_head->hch_mtx);
 635 }
 636
 637 /*
 638  * Sysctl function: prints the list and values of all hostcache entries in
 639  * unsorted order.
 640  */
 641 static int
 642 sysctl_tcp_hc_list(SYSCTL_HANDLER_ARGS)
 643 {
 644         const int linesize = 128;
 645         struct sbuf sb;
 646         int i, error, len;
 647         struct hc_metrics *hc_entry;
 648         char ip4buf[INET_ADDRSTRLEN];
 649 #ifdef INET6
 650         char ip6buf[INET6_ADDRSTRLEN];
 651 #endif
 652
 653         if (jailed_without_vnet(curthread->td_ucred) != 0)
 654                 return (EPERM);
 655
 656         /* Optimize Buffer length query by sbin/sysctl */
 657         if (req->oldptr == NULL) {
 658                 len = (atomic_load_int(&V_tcp_hostcache.cache_count) + 1) *
 659                         linesize;
 660                 return (SYSCTL_OUT(req, NULL, len));
 661         }
 662
 663         error = sysctl_wire_old_buffer(req, 0);
 664         if (error != 0) {
 665                 return(error);
 666         }
 667
 668         /* Use a buffer sized for one full bucket */
 669         sbuf_new_for_sysctl(&sb, NULL, V_tcp_hostcache.bucket_limit *
 670                 linesize, req);
 671
 672         sbuf_printf(&sb,
 673                 "\nIP address        MTU  SSTRESH      RTT   RTTVAR "
 674                 "    CWND SENDPIPE RECVPIPE HITS  UPD  EXP\n");
 675         sbuf_drain(&sb);
 676
 677 #define msec(u) (((u) + 500) / 1000)
 678         for (i = 0; i < V_tcp_hostcache.hashsize; i++) {
 679                 THC_LOCK(&V_tcp_hostcache.hashbase[i].hch_mtx);
 680                 TAILQ_FOREACH(hc_entry, &V_tcp_hostcache.hashbase[i].hch_bucket,
 681                               rmx_q) {
 682                         sbuf_printf(&sb,
 683                             "%-15s %5u %8u %6lums %6lums %8u %8u %8u %4lu "
 684                             "%4lu %4i\n",
 685                             hc_entry->ip4.s_addr ?
 686                                 inet_ntoa_r(hc_entry->ip4, ip4buf) :
 687 #ifdef INET6
 688                                 ip6_sprintf(ip6buf, &hc_entry->ip6),
 689 #else
 690                                 "IPv6?",
 691 #endif
 692                             hc_entry->rmx_mtu,
 693                             hc_entry->rmx_ssthresh,
 694                             msec((u_long)hc_entry->rmx_rtt *
 695                                 (RTM_RTTUNIT / (hz * TCP_RTT_SCALE))),
 696                             msec((u_long)hc_entry->rmx_rttvar *
 697                                 (RTM_RTTUNIT / (hz * TCP_RTTVAR_SCALE))),
 698                             hc_entry->rmx_cwnd,
 699                             hc_entry->rmx_sendpipe,
 700                             hc_entry->rmx_recvpipe,
 701                             hc_entry->rmx_hits,
 702                             hc_entry->rmx_updates,
 703                             hc_entry->rmx_expire);
 704                 }
 705                 THC_UNLOCK(&V_tcp_hostcache.hashbase[i].hch_mtx);
 706                 sbuf_drain(&sb);
 707         }
 708 #undef msec
 709         error = sbuf_finish(&sb);
 710         sbuf_delete(&sb);
 711         return(error);
 712 }
 713
 714 /*
 715  * Sysctl function: prints a histogram of the hostcache hashbucket
 716  * utilization.
 717  */
 718 static int
 719 sysctl_tcp_hc_histo(SYSCTL_HANDLER_ARGS)
 720 {
 721         const int linesize = 50;
 722         struct sbuf sb;
 723         int i, error;
 724         int *histo;
 725         u_int hch_length;
 726
 727         if (jailed_without_vnet(curthread->td_ucred) != 0)
 728                 return (EPERM);
 729
 730         histo = (int *)malloc(sizeof(int) * (V_tcp_hostcache.bucket_limit + 1),
 731                         M_TEMP, M_NOWAIT|M_ZERO);
 732         if (histo == NULL)
 733                 return(ENOMEM);
 734
 735         for (i = 0; i < V_tcp_hostcache.hashsize; i++) {
 736                 hch_length = V_tcp_hostcache.hashbase[i].hch_length;
 737                 KASSERT(hch_length <= V_tcp_hostcache.bucket_limit,
 738                         ("tcp_hostcache: bucket limit exceeded at %u: %u",
 739                         i, hch_length));
 740                 histo[hch_length]++;
 741         }
 742
 743         /* Use a buffer for 16 lines */
 744         sbuf_new_for_sysctl(&sb, NULL, 16 * linesize, req);
 745
 746         sbuf_printf(&sb, "\nLength\tCount\n");
 747         for (i = 0; i <= V_tcp_hostcache.bucket_limit; i++) {
 748                 sbuf_printf(&sb, "%u\t%u\n", i, histo[i]);
 749         }
 750         error = sbuf_finish(&sb);
 751         sbuf_delete(&sb);
 752         free(histo, M_TEMP);
 753         return(error);
 754 }
 755
 756 /*
 757  * Caller has to make sure the curvnet is set properly.
 758  */
 759 static void
 760 tcp_hc_purge_internal(int all)
 761 {
 762         struct hc_metrics *hc_entry, *hc_next;
 763         int i;
 764
 765         for (i = 0; i < V_tcp_hostcache.hashsize; i++) {
 766                 THC_LOCK(&V_tcp_hostcache.hashbase[i].hch_mtx);
 767                 TAILQ_FOREACH_SAFE(hc_entry,
 768                     &V_tcp_hostcache.hashbase[i].hch_bucket, rmx_q, hc_next) {
 769                         KASSERT(V_tcp_hostcache.hashbase[i].hch_length > 0 &&
 770                                 V_tcp_hostcache.hashbase[i].hch_length <=
 771                                 V_tcp_hostcache.bucket_limit,
 772                                 ("tcp_hostcache: bucket length out of range at %u: %u",
 773                                 i, V_tcp_hostcache.hashbase[i].hch_length));
 774                         if (all || hc_entry->rmx_expire <= 0) {
 775                                 TAILQ_REMOVE(&V_tcp_hostcache.hashbase[i].hch_bucket,
 776                                               hc_entry, rmx_q);
 777                                 uma_zfree(V_tcp_hostcache.zone, hc_entry);
 778                                 V_tcp_hostcache.hashbase[i].hch_length--;
 779                                 atomic_subtract_int(&V_tcp_hostcache.cache_count, 1);
 780                         } else
 781                                 hc_entry->rmx_expire -= V_tcp_hostcache.prune;
 782                 }
 783                 THC_UNLOCK(&V_tcp_hostcache.hashbase[i].hch_mtx);
 784         }
 785 }
 786
 787 /*
 788  * Expire and purge (old|all) entries in the tcp_hostcache.  Runs
 789  * periodically from the callout.
 790  */
 791 static void
 792 tcp_hc_purge(void *arg)
 793 {
 794         CURVNET_SET((struct vnet *) arg);
 795         int all = 0;
 796
 797         if (V_tcp_hostcache.purgeall) {
 798                 if (V_tcp_hostcache.purgeall == 2)
 799                         V_tcp_hostcache.hashsalt = arc4random();
 800                 all = 1;
 801                 V_tcp_hostcache.purgeall = 0;
 802         }
 803
 804         tcp_hc_purge_internal(all);
 805
 806         callout_reset(&V_tcp_hc_callout, V_tcp_hostcache.prune * hz,
 807             tcp_hc_purge, arg);
 808         CURVNET_RESTORE();
 809 }
 810
 811 /*
 812  * Expire and purge all entries in hostcache immediately.
 813  */
 814 static int
 815 sysctl_tcp_hc_purgenow(SYSCTL_HANDLER_ARGS)
 816 {
 817         int error, val;
 818
 819         val = 0;
 820         error = sysctl_handle_int(oidp, &val, 0, req);
 821         if (error || !req->newptr)
 822                 return (error);
 823
 824         if (val == 2)
 825                 V_tcp_hostcache.hashsalt = arc4random();
 826         tcp_hc_purge_internal(1);
 827
 828         callout_reset(&V_tcp_hc_callout, V_tcp_hostcache.prune * hz,
 829             tcp_hc_purge, curvnet);
 830
 831         return (0);
 832 }