sys/netinet/tcp_hostcache.c

   1 /*-
   2  * Copyright (c) 2002 Andre Oppermann, Internet Business Solutions AG
   3  * All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions and the following disclaimer.
  10  * 2. Redistributions in binary form must reproduce the above copyright
  11  *    notice, this list of conditions and the following disclaimer in the
  12  *    documentation and/or other materials provided with the distribution.
  13  * 3. The name of the author may not be used to endorse or promote
  14  *    products derived from this software without specific prior written
  15  *    permission.
  16  *
  17  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  27  * SUCH DAMAGE.
  28  */
  29
  30 /*
  31  * The tcp_hostcache moves the tcp-specific cached metrics from the routing
  32  * table to a dedicated structure indexed by the remote IP address.  It keeps
  33  * information on the measured TCP parameters of past TCP sessions to allow
  34  * better initial start values to be used with later connections to/from the
  35  * same source.  Depending on the network parameters (delay, max MTU,
  36  * congestion window) between local and remote sites, this can lead to
  37  * significant speed-ups for new TCP connections after the first one.
  38  *
  39  * Due to the tcp_hostcache, all TCP-specific metrics information in the
  40  * routing table have been removed.  The inpcb no longer keeps a pointer to
  41  * the routing entry, and protocol-initiated route cloning has been removed
  42  * as well.  With these changes, the routing table has gone back to being
  43  * more lightwight and only carries information related to packet forwarding.
  44  *
  45  * tcp_hostcache is designed for multiple concurrent access in SMP
  46  * environments and high contention.  All bucket rows have their own lock and
  47  * thus multiple lookups and modifies can be done at the same time as long as
  48  * they are in different bucket rows.  If a request for insertion of a new
  49  * record can't be satisfied, it simply returns an empty structure.  Nobody
  50  * and nothing outside of tcp_hostcache.c will ever point directly to any
  51  * entry in the tcp_hostcache.  All communication is done in an
  52  * object-oriented way and only functions of tcp_hostcache will manipulate
  53  * hostcache entries.  Otherwise, we are unable to achieve good behaviour in
  54  * concurrent access situations.  Since tcp_hostcache is only caching
  55  * information, there are no fatal consequences if we either can't satisfy
  56  * any particular request or have to drop/overwrite an existing entry because
  57  * of bucket limit memory constrains.
  58  */
  59
  60 /*
  61  * Many thanks to jlemon for basic structure of tcp_syncache which is being
  62  * followed here.
  63  */
  64
  65 #include <sys/cdefs.h>
  66 __FBSDID("$FreeBSD$");
  67
  68 #include "opt_inet6.h"
  69
  70 #include <sys/param.h>
  71 #include <sys/systm.h>
  72 #include <sys/jail.h>
  73 #include <sys/kernel.h>
  74 #include <sys/lock.h>
  75 #include <sys/mutex.h>
  76 #include <sys/malloc.h>
  77 #include <sys/proc.h>
  78 #include <sys/sbuf.h>
  79 #include <sys/socket.h>
  80 #include <sys/socketvar.h>
  81 #include <sys/sysctl.h>
  82
  83 #include <net/if.h>
  84 #include <net/if_var.h>
  85 #include <net/route.h>
  86 #include <net/vnet.h>
  87
  88 #include <netinet/in.h>
  89 #include <netinet/in_systm.h>
  90 #include <netinet/ip.h>
  91 #include <netinet/in_var.h>
  92 #include <netinet/in_pcb.h>
  93 #include <netinet/ip_var.h>
  94 #ifdef INET6
  95 #include <netinet/ip6.h>
  96 #include <netinet6/ip6_var.h>
  97 #endif
  98 #include <netinet/tcp.h>
  99 #include <netinet/tcp_var.h>
 100 #include <netinet/tcp_hostcache.h>
 101 #ifdef INET6
 102 #include <netinet6/tcp6_var.h>
 103 #endif
 104
 105 #include <vm/uma.h>
 106
 107 /* Arbitrary values */
 108 #define TCP_HOSTCACHE_HASHSIZE          512
 109 #define TCP_HOSTCACHE_BUCKETLIMIT       30
 110 #define TCP_HOSTCACHE_EXPIRE            60*60   /* one hour */
 111 #define TCP_HOSTCACHE_PRUNE             5*60    /* every 5 minutes */
 112
 113 static VNET_DEFINE(struct tcp_hostcache, tcp_hostcache);
 114 #define V_tcp_hostcache         VNET(tcp_hostcache)
 115
 116 static VNET_DEFINE(struct callout, tcp_hc_callout);
 117 #define V_tcp_hc_callout        VNET(tcp_hc_callout)
 118
 119 static struct hc_metrics *tcp_hc_lookup(struct in_conninfo *);
 120 static struct hc_metrics *tcp_hc_insert(struct in_conninfo *);
 121 static int sysctl_tcp_hc_list(SYSCTL_HANDLER_ARGS);
 122 static int sysctl_tcp_hc_purgenow(SYSCTL_HANDLER_ARGS);
 123 static void tcp_hc_purge_internal(int);
 124 static void tcp_hc_purge(void *);
 125
 126 static SYSCTL_NODE(_net_inet_tcp, OID_AUTO, hostcache, CTLFLAG_RW, 0,
 127     "TCP Host cache");
 128
 129 VNET_DEFINE(int, tcp_use_hostcache) = 1;
 130 #define V_tcp_use_hostcache  VNET(tcp_use_hostcache)
 131 SYSCTL_INT(_net_inet_tcp_hostcache, OID_AUTO, enable, CTLFLAG_VNET | CTLFLAG_RW,
 132     &VNET_NAME(tcp_use_hostcache), 0,
 133     "Enable the TCP hostcache");
 134
 135 SYSCTL_UINT(_net_inet_tcp_hostcache, OID_AUTO, cachelimit, CTLFLAG_VNET | CTLFLAG_RDTUN,
 136     &VNET_NAME(tcp_hostcache.cache_limit), 0,
 137     "Overall entry limit for hostcache");
 138
 139 SYSCTL_UINT(_net_inet_tcp_hostcache, OID_AUTO, hashsize, CTLFLAG_VNET | CTLFLAG_RDTUN,
 140     &VNET_NAME(tcp_hostcache.hashsize), 0,
 141     "Size of TCP hostcache hashtable");
 142
 143 SYSCTL_UINT(_net_inet_tcp_hostcache, OID_AUTO, bucketlimit,
 144     CTLFLAG_VNET | CTLFLAG_RDTUN, &VNET_NAME(tcp_hostcache.bucket_limit), 0,
 145     "Per-bucket hash limit for hostcache");
 146
 147 SYSCTL_UINT(_net_inet_tcp_hostcache, OID_AUTO, count, CTLFLAG_VNET | CTLFLAG_RD,
 148      &VNET_NAME(tcp_hostcache.cache_count), 0,
 149     "Current number of entries in hostcache");
 150
 151 SYSCTL_INT(_net_inet_tcp_hostcache, OID_AUTO, expire, CTLFLAG_VNET | CTLFLAG_RW,
 152     &VNET_NAME(tcp_hostcache.expire), 0,
 153     "Expire time of TCP hostcache entries");
 154
 155 SYSCTL_INT(_net_inet_tcp_hostcache, OID_AUTO, prune, CTLFLAG_VNET | CTLFLAG_RW,
 156     &VNET_NAME(tcp_hostcache.prune), 0,
 157     "Time between purge runs");
 158
 159 SYSCTL_INT(_net_inet_tcp_hostcache, OID_AUTO, purge, CTLFLAG_VNET | CTLFLAG_RW,
 160     &VNET_NAME(tcp_hostcache.purgeall), 0,
 161     "Expire all entires on next purge run");
 162
 163 SYSCTL_PROC(_net_inet_tcp_hostcache, OID_AUTO, list,
 164     CTLTYPE_STRING | CTLFLAG_RD | CTLFLAG_SKIP, 0, 0,
 165     sysctl_tcp_hc_list, "A", "List of all hostcache entries");
 166
 167 SYSCTL_PROC(_net_inet_tcp_hostcache, OID_AUTO, purgenow,
 168     CTLTYPE_INT | CTLFLAG_RW, NULL, 0,
 169     sysctl_tcp_hc_purgenow, "I", "Immediately purge all entries");
 170
 171 static MALLOC_DEFINE(M_HOSTCACHE, "hostcache", "TCP hostcache");
 172
 173 #define HOSTCACHE_HASH(ip) \
 174         (((ip)->s_addr ^ ((ip)->s_addr >> 7) ^ ((ip)->s_addr >> 17)) &  \
 175           V_tcp_hostcache.hashmask)
 176
 177 /* XXX: What is the recommended hash to get good entropy for IPv6 addresses? */
 178 #define HOSTCACHE_HASH6(ip6)                            \
 179         (((ip6)->s6_addr32[0] ^                         \
 180           (ip6)->s6_addr32[1] ^                         \
 181           (ip6)->s6_addr32[2] ^                         \
 182           (ip6)->s6_addr32[3]) &                        \
 183          V_tcp_hostcache.hashmask)
 184
 185 #define THC_LOCK(lp)            mtx_lock(lp)
 186 #define THC_UNLOCK(lp)          mtx_unlock(lp)
 187
 188 void
 189 tcp_hc_init(void)
 190 {
 191         u_int cache_limit;
 192         int i;
 193
 194         /*
 195          * Initialize hostcache structures.
 196          */
 197         V_tcp_hostcache.cache_count = 0;
 198         V_tcp_hostcache.hashsize = TCP_HOSTCACHE_HASHSIZE;
 199         V_tcp_hostcache.bucket_limit = TCP_HOSTCACHE_BUCKETLIMIT;
 200         V_tcp_hostcache.expire = TCP_HOSTCACHE_EXPIRE;
 201         V_tcp_hostcache.prune = TCP_HOSTCACHE_PRUNE;
 202
 203         TUNABLE_INT_FETCH("net.inet.tcp.hostcache.hashsize",
 204             &V_tcp_hostcache.hashsize);
 205         if (!powerof2(V_tcp_hostcache.hashsize)) {
 206                 printf("WARNING: hostcache hash size is not a power of 2.\n");
 207                 V_tcp_hostcache.hashsize = TCP_HOSTCACHE_HASHSIZE; /* default */
 208         }
 209         V_tcp_hostcache.hashmask = V_tcp_hostcache.hashsize - 1;
 210
 211         TUNABLE_INT_FETCH("net.inet.tcp.hostcache.bucketlimit",
 212             &V_tcp_hostcache.bucket_limit);
 213
 214         cache_limit = V_tcp_hostcache.hashsize * V_tcp_hostcache.bucket_limit;
 215         V_tcp_hostcache.cache_limit = cache_limit;
 216         TUNABLE_INT_FETCH("net.inet.tcp.hostcache.cachelimit",
 217             &V_tcp_hostcache.cache_limit);
 218         if (V_tcp_hostcache.cache_limit > cache_limit)
 219                 V_tcp_hostcache.cache_limit = cache_limit;
 220
 221         /*
 222          * Allocate the hash table.
 223          */
 224         V_tcp_hostcache.hashbase = (struct hc_head *)
 225             malloc(V_tcp_hostcache.hashsize * sizeof(struct hc_head),
 226                    M_HOSTCACHE, M_WAITOK | M_ZERO);
 227
 228         /*
 229          * Initialize the hash buckets.
 230          */
 231         for (i = 0; i < V_tcp_hostcache.hashsize; i++) {
 232                 TAILQ_INIT(&V_tcp_hostcache.hashbase[i].hch_bucket);
 233                 V_tcp_hostcache.hashbase[i].hch_length = 0;
 234                 mtx_init(&V_tcp_hostcache.hashbase[i].hch_mtx, "tcp_hc_entry",
 235                           NULL, MTX_DEF);
 236         }
 237
 238         /*
 239          * Allocate the hostcache entries.
 240          */
 241         V_tcp_hostcache.zone =
 242             uma_zcreate("hostcache", sizeof(struct hc_metrics),
 243             NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, 0);
 244         uma_zone_set_max(V_tcp_hostcache.zone, V_tcp_hostcache.cache_limit);
 245
 246         /*
 247          * Set up periodic cache cleanup.
 248          */
 249         callout_init(&V_tcp_hc_callout, 1);
 250         callout_reset(&V_tcp_hc_callout, V_tcp_hostcache.prune * hz,
 251             tcp_hc_purge, curvnet);
 252 }
 253
 254 #ifdef VIMAGE
 255 void
 256 tcp_hc_destroy(void)
 257 {
 258         int i;
 259
 260         callout_drain(&V_tcp_hc_callout);
 261
 262         /* Purge all hc entries. */
 263         tcp_hc_purge_internal(1);
 264
 265         /* Free the uma zone and the allocated hash table. */
 266         uma_zdestroy(V_tcp_hostcache.zone);
 267
 268         for (i = 0; i < V_tcp_hostcache.hashsize; i++)
 269                 mtx_destroy(&V_tcp_hostcache.hashbase[i].hch_mtx);
 270         free(V_tcp_hostcache.hashbase, M_HOSTCACHE);
 271 }
 272 #endif
 273
 274 /*
 275  * Internal function: look up an entry in the hostcache or return NULL.
 276  *
 277  * If an entry has been returned, the caller becomes responsible for
 278  * unlocking the bucket row after he is done reading/modifying the entry.
 279  */
 280 static struct hc_metrics *
 281 tcp_hc_lookup(struct in_conninfo *inc)
 282 {
 283         int hash;
 284         struct hc_head *hc_head;
 285         struct hc_metrics *hc_entry;
 286
 287         if (!V_tcp_use_hostcache)
 288                 return NULL;
 289
 290         KASSERT(inc != NULL, ("tcp_hc_lookup with NULL in_conninfo pointer"));
 291
 292         /*
 293          * Hash the foreign ip address.
 294          */
 295         if (inc->inc_flags & INC_ISIPV6)
 296                 hash = HOSTCACHE_HASH6(&inc->inc6_faddr);
 297         else
 298                 hash = HOSTCACHE_HASH(&inc->inc_faddr);
 299
 300         hc_head = &V_tcp_hostcache.hashbase[hash];
 301
 302         /*
 303          * Acquire lock for this bucket row; we release the lock if we don't
 304          * find an entry, otherwise the caller has to unlock after he is
 305          * done.
 306          */
 307         THC_LOCK(&hc_head->hch_mtx);
 308
 309         /*
 310          * Iterate through entries in bucket row looking for a match.
 311          */
 312         TAILQ_FOREACH(hc_entry, &hc_head->hch_bucket, rmx_q) {
 313                 if (inc->inc_flags & INC_ISIPV6) {
 314                         /* XXX: check ip6_zoneid */
 315                         if (memcmp(&inc->inc6_faddr, &hc_entry->ip6,
 316                             sizeof(inc->inc6_faddr)) == 0)
 317                                 return hc_entry;
 318                 } else {
 319                         if (memcmp(&inc->inc_faddr, &hc_entry->ip4,
 320                             sizeof(inc->inc_faddr)) == 0)
 321                                 return hc_entry;
 322                 }
 323         }
 324
 325         /*
 326          * We were unsuccessful and didn't find anything.
 327          */
 328         THC_UNLOCK(&hc_head->hch_mtx);
 329         return NULL;
 330 }
 331
 332 /*
 333  * Internal function: insert an entry into the hostcache or return NULL if
 334  * unable to allocate a new one.
 335  *
 336  * If an entry has been returned, the caller becomes responsible for
 337  * unlocking the bucket row after he is done reading/modifying the entry.
 338  */
 339 static struct hc_metrics *
 340 tcp_hc_insert(struct in_conninfo *inc)
 341 {
 342         int hash;
 343         struct hc_head *hc_head;
 344         struct hc_metrics *hc_entry;
 345
 346         if (!V_tcp_use_hostcache)
 347                 return NULL;
 348
 349         KASSERT(inc != NULL, ("tcp_hc_insert with NULL in_conninfo pointer"));
 350
 351         /*
 352          * Hash the foreign ip address.
 353          */
 354         if (inc->inc_flags & INC_ISIPV6)
 355                 hash = HOSTCACHE_HASH6(&inc->inc6_faddr);
 356         else
 357                 hash = HOSTCACHE_HASH(&inc->inc_faddr);
 358
 359         hc_head = &V_tcp_hostcache.hashbase[hash];
 360
 361         /*
 362          * Acquire lock for this bucket row; we release the lock if we don't
 363          * find an entry, otherwise the caller has to unlock after he is
 364          * done.
 365          */
 366         THC_LOCK(&hc_head->hch_mtx);
 367
 368         /*
 369          * If the bucket limit is reached, reuse the least-used element.
 370          */
 371         if (hc_head->hch_length >= V_tcp_hostcache.bucket_limit ||
 372             V_tcp_hostcache.cache_count >= V_tcp_hostcache.cache_limit) {
 373                 hc_entry = TAILQ_LAST(&hc_head->hch_bucket, hc_qhead);
 374                 /*
 375                  * At first we were dropping the last element, just to
 376                  * reacquire it in the next two lines again, which isn't very
 377                  * efficient.  Instead just reuse the least used element.
 378                  * We may drop something that is still "in-use" but we can be
 379                  * "lossy".
 380                  * Just give up if this bucket row is empty and we don't have
 381                  * anything to replace.
 382                  */
 383                 if (hc_entry == NULL) {
 384                         THC_UNLOCK(&hc_head->hch_mtx);
 385                         return NULL;
 386                 }
 387                 TAILQ_REMOVE(&hc_head->hch_bucket, hc_entry, rmx_q);
 388                 V_tcp_hostcache.hashbase[hash].hch_length--;
 389                 V_tcp_hostcache.cache_count--;
 390                 TCPSTAT_INC(tcps_hc_bucketoverflow);
 391 #if 0
 392                 uma_zfree(V_tcp_hostcache.zone, hc_entry);
 393 #endif
 394         } else {
 395                 /*
 396                  * Allocate a new entry, or balk if not possible.
 397                  */
 398                 hc_entry = uma_zalloc(V_tcp_hostcache.zone, M_NOWAIT);
 399                 if (hc_entry == NULL) {
 400                         THC_UNLOCK(&hc_head->hch_mtx);
 401                         return NULL;
 402                 }
 403         }
 404
 405         /*
 406          * Initialize basic information of hostcache entry.
 407          */
 408         bzero(hc_entry, sizeof(*hc_entry));
 409         if (inc->inc_flags & INC_ISIPV6) {
 410                 hc_entry->ip6 = inc->inc6_faddr;
 411                 hc_entry->ip6_zoneid = inc->inc6_zoneid;
 412         } else
 413                 hc_entry->ip4 = inc->inc_faddr;
 414         hc_entry->rmx_head = hc_head;
 415         hc_entry->rmx_expire = V_tcp_hostcache.expire;
 416
 417         /*
 418          * Put it upfront.
 419          */
 420         TAILQ_INSERT_HEAD(&hc_head->hch_bucket, hc_entry, rmx_q);
 421         V_tcp_hostcache.hashbase[hash].hch_length++;
 422         V_tcp_hostcache.cache_count++;
 423         TCPSTAT_INC(tcps_hc_added);
 424
 425         return hc_entry;
 426 }
 427
 428 /*
 429  * External function: look up an entry in the hostcache and fill out the
 430  * supplied TCP metrics structure.  Fills in NULL when no entry was found or
 431  * a value is not set.
 432  */
 433 void
 434 tcp_hc_get(struct in_conninfo *inc, struct hc_metrics_lite *hc_metrics_lite)
 435 {
 436         struct hc_metrics *hc_entry;
 437
 438         if (!V_tcp_use_hostcache)
 439                 return;
 440
 441         /*
 442          * Find the right bucket.
 443          */
 444         hc_entry = tcp_hc_lookup(inc);
 445
 446         /*
 447          * If we don't have an existing object.
 448          */
 449         if (hc_entry == NULL) {
 450                 bzero(hc_metrics_lite, sizeof(*hc_metrics_lite));
 451                 return;
 452         }
 453         hc_entry->rmx_hits++;
 454         hc_entry->rmx_expire = V_tcp_hostcache.expire; /* start over again */
 455
 456         hc_metrics_lite->rmx_mtu = hc_entry->rmx_mtu;
 457         hc_metrics_lite->rmx_ssthresh = hc_entry->rmx_ssthresh;
 458         hc_metrics_lite->rmx_rtt = hc_entry->rmx_rtt;
 459         hc_metrics_lite->rmx_rttvar = hc_entry->rmx_rttvar;
 460         hc_metrics_lite->rmx_cwnd = hc_entry->rmx_cwnd;
 461         hc_metrics_lite->rmx_sendpipe = hc_entry->rmx_sendpipe;
 462         hc_metrics_lite->rmx_recvpipe = hc_entry->rmx_recvpipe;
 463
 464         /*
 465          * Unlock bucket row.
 466          */
 467         THC_UNLOCK(&hc_entry->rmx_head->hch_mtx);
 468 }
 469
 470 /*
 471  * External function: look up an entry in the hostcache and return the
 472  * discovered path MTU.  Returns 0 if no entry is found or value is not
 473  * set.
 474  */
 475 u_long
 476 tcp_hc_getmtu(struct in_conninfo *inc)
 477 {
 478         struct hc_metrics *hc_entry;
 479         u_long mtu;
 480
 481         if (!V_tcp_use_hostcache)
 482                 return 0;
 483
 484         hc_entry = tcp_hc_lookup(inc);
 485         if (hc_entry == NULL) {
 486                 return 0;
 487         }
 488         hc_entry->rmx_hits++;
 489         hc_entry->rmx_expire = V_tcp_hostcache.expire; /* start over again */
 490
 491         mtu = hc_entry->rmx_mtu;
 492         THC_UNLOCK(&hc_entry->rmx_head->hch_mtx);
 493         return mtu;
 494 }
 495
 496 /*
 497  * External function: update the MTU value of an entry in the hostcache.
 498  * Creates a new entry if none was found.
 499  */
 500 void
 501 tcp_hc_updatemtu(struct in_conninfo *inc, u_long mtu)
 502 {
 503         struct hc_metrics *hc_entry;
 504
 505         if (!V_tcp_use_hostcache)
 506                 return;
 507
 508         /*
 509          * Find the right bucket.
 510          */
 511         hc_entry = tcp_hc_lookup(inc);
 512
 513         /*
 514          * If we don't have an existing object, try to insert a new one.
 515          */
 516         if (hc_entry == NULL) {
 517                 hc_entry = tcp_hc_insert(inc);
 518                 if (hc_entry == NULL)
 519                         return;
 520         }
 521         hc_entry->rmx_updates++;
 522         hc_entry->rmx_expire = V_tcp_hostcache.expire; /* start over again */
 523
 524         hc_entry->rmx_mtu = mtu;
 525
 526         /*
 527          * Put it upfront so we find it faster next time.
 528          */
 529         TAILQ_REMOVE(&hc_entry->rmx_head->hch_bucket, hc_entry, rmx_q);
 530         TAILQ_INSERT_HEAD(&hc_entry->rmx_head->hch_bucket, hc_entry, rmx_q);
 531
 532         /*
 533          * Unlock bucket row.
 534          */
 535         THC_UNLOCK(&hc_entry->rmx_head->hch_mtx);
 536 }
 537
 538 /*
 539  * External function: update the TCP metrics of an entry in the hostcache.
 540  * Creates a new entry if none was found.
 541  */
 542 void
 543 tcp_hc_update(struct in_conninfo *inc, struct hc_metrics_lite *hcml)
 544 {
 545         struct hc_metrics *hc_entry;
 546
 547         if (!V_tcp_use_hostcache)
 548                 return;
 549
 550         hc_entry = tcp_hc_lookup(inc);
 551         if (hc_entry == NULL) {
 552                 hc_entry = tcp_hc_insert(inc);
 553                 if (hc_entry == NULL)
 554                         return;
 555         }
 556         hc_entry->rmx_updates++;
 557         hc_entry->rmx_expire = V_tcp_hostcache.expire; /* start over again */
 558
 559         if (hcml->rmx_rtt != 0) {
 560                 if (hc_entry->rmx_rtt == 0)
 561                         hc_entry->rmx_rtt = hcml->rmx_rtt;
 562                 else
 563                         hc_entry->rmx_rtt =
 564                             (hc_entry->rmx_rtt + hcml->rmx_rtt) / 2;
 565                 TCPSTAT_INC(tcps_cachedrtt);
 566         }
 567         if (hcml->rmx_rttvar != 0) {
 568                 if (hc_entry->rmx_rttvar == 0)
 569                         hc_entry->rmx_rttvar = hcml->rmx_rttvar;
 570                 else
 571                         hc_entry->rmx_rttvar =
 572                             (hc_entry->rmx_rttvar + hcml->rmx_rttvar) / 2;
 573                 TCPSTAT_INC(tcps_cachedrttvar);
 574         }
 575         if (hcml->rmx_ssthresh != 0) {
 576                 if (hc_entry->rmx_ssthresh == 0)
 577                         hc_entry->rmx_ssthresh = hcml->rmx_ssthresh;
 578                 else
 579                         hc_entry->rmx_ssthresh =
 580                             (hc_entry->rmx_ssthresh + hcml->rmx_ssthresh) / 2;
 581                 TCPSTAT_INC(tcps_cachedssthresh);
 582         }
 583         if (hcml->rmx_cwnd != 0) {
 584                 if (hc_entry->rmx_cwnd == 0)
 585                         hc_entry->rmx_cwnd = hcml->rmx_cwnd;
 586                 else
 587                         hc_entry->rmx_cwnd =
 588                             (hc_entry->rmx_cwnd + hcml->rmx_cwnd) / 2;
 589                 /* TCPSTAT_INC(tcps_cachedcwnd); */
 590         }
 591         if (hcml->rmx_sendpipe != 0) {
 592                 if (hc_entry->rmx_sendpipe == 0)
 593                         hc_entry->rmx_sendpipe = hcml->rmx_sendpipe;
 594                 else
 595                         hc_entry->rmx_sendpipe =
 596                             (hc_entry->rmx_sendpipe + hcml->rmx_sendpipe) /2;
 597                 /* TCPSTAT_INC(tcps_cachedsendpipe); */
 598         }
 599         if (hcml->rmx_recvpipe != 0) {
 600                 if (hc_entry->rmx_recvpipe == 0)
 601                         hc_entry->rmx_recvpipe = hcml->rmx_recvpipe;
 602                 else
 603                         hc_entry->rmx_recvpipe =
 604                             (hc_entry->rmx_recvpipe + hcml->rmx_recvpipe) /2;
 605                 /* TCPSTAT_INC(tcps_cachedrecvpipe); */
 606         }
 607
 608         TAILQ_REMOVE(&hc_entry->rmx_head->hch_bucket, hc_entry, rmx_q);
 609         TAILQ_INSERT_HEAD(&hc_entry->rmx_head->hch_bucket, hc_entry, rmx_q);
 610         THC_UNLOCK(&hc_entry->rmx_head->hch_mtx);
 611 }
 612
 613 /*
 614  * Sysctl function: prints the list and values of all hostcache entries in
 615  * unsorted order.
 616  */
 617 static int
 618 sysctl_tcp_hc_list(SYSCTL_HANDLER_ARGS)
 619 {
 620         const int linesize = 128;
 621         struct sbuf sb;
 622         int i, error;
 623         struct hc_metrics *hc_entry;
 624         char ip4buf[INET_ADDRSTRLEN];
 625 #ifdef INET6
 626         char ip6buf[INET6_ADDRSTRLEN];
 627 #endif
 628
 629         if (jailed_without_vnet(curthread->td_ucred) != 0)
 630                 return (EPERM);
 631
 632         sbuf_new(&sb, NULL, linesize * (V_tcp_hostcache.cache_count + 1),
 633                 SBUF_INCLUDENUL);
 634
 635         sbuf_printf(&sb,
 636                 "\nIP address        MTU  SSTRESH      RTT   RTTVAR "
 637                 "    CWND SENDPIPE RECVPIPE HITS  UPD  EXP\n");
 638
 639 #define msec(u) (((u) + 500) / 1000)
 640         for (i = 0; i < V_tcp_hostcache.hashsize; i++) {
 641                 THC_LOCK(&V_tcp_hostcache.hashbase[i].hch_mtx);
 642                 TAILQ_FOREACH(hc_entry, &V_tcp_hostcache.hashbase[i].hch_bucket,
 643                               rmx_q) {
 644                         sbuf_printf(&sb,
 645                             "%-15s %5lu %8lu %6lums %6lums %8lu %8lu %8lu %4lu "
 646                             "%4lu %4i\n",
 647                             hc_entry->ip4.s_addr ?
 648                                 inet_ntoa_r(hc_entry->ip4, ip4buf) :
 649 #ifdef INET6
 650                                 ip6_sprintf(ip6buf, &hc_entry->ip6),
 651 #else
 652                                 "IPv6?",
 653 #endif
 654                             hc_entry->rmx_mtu,
 655                             hc_entry->rmx_ssthresh,
 656                             msec(hc_entry->rmx_rtt *
 657                                 (RTM_RTTUNIT / (hz * TCP_RTT_SCALE))),
 658                             msec(hc_entry->rmx_rttvar *
 659                                 (RTM_RTTUNIT / (hz * TCP_RTTVAR_SCALE))),
 660                             hc_entry->rmx_cwnd,
 661                             hc_entry->rmx_sendpipe,
 662                             hc_entry->rmx_recvpipe,
 663                             hc_entry->rmx_hits,
 664                             hc_entry->rmx_updates,
 665                             hc_entry->rmx_expire);
 666                 }
 667                 THC_UNLOCK(&V_tcp_hostcache.hashbase[i].hch_mtx);
 668         }
 669 #undef msec
 670         error = sbuf_finish(&sb);
 671         if (error == 0)
 672                 error = SYSCTL_OUT(req, sbuf_data(&sb), sbuf_len(&sb));
 673         sbuf_delete(&sb);
 674         return(error);
 675 }
 676
 677 /*
 678  * Caller has to make sure the curvnet is set properly.
 679  */
 680 static void
 681 tcp_hc_purge_internal(int all)
 682 {
 683         struct hc_metrics *hc_entry, *hc_next;
 684         int i;
 685
 686         for (i = 0; i < V_tcp_hostcache.hashsize; i++) {
 687                 THC_LOCK(&V_tcp_hostcache.hashbase[i].hch_mtx);
 688                 TAILQ_FOREACH_SAFE(hc_entry,
 689                     &V_tcp_hostcache.hashbase[i].hch_bucket, rmx_q, hc_next) {
 690                         if (all || hc_entry->rmx_expire <= 0) {
 691                                 TAILQ_REMOVE(&V_tcp_hostcache.hashbase[i].hch_bucket,
 692                                               hc_entry, rmx_q);
 693                                 uma_zfree(V_tcp_hostcache.zone, hc_entry);
 694                                 V_tcp_hostcache.hashbase[i].hch_length--;
 695                                 V_tcp_hostcache.cache_count--;
 696                         } else
 697                                 hc_entry->rmx_expire -= V_tcp_hostcache.prune;
 698                 }
 699                 THC_UNLOCK(&V_tcp_hostcache.hashbase[i].hch_mtx);
 700         }
 701 }
 702
 703 /*
 704  * Expire and purge (old|all) entries in the tcp_hostcache.  Runs
 705  * periodically from the callout.
 706  */
 707 static void
 708 tcp_hc_purge(void *arg)
 709 {
 710         CURVNET_SET((struct vnet *) arg);
 711         int all = 0;
 712
 713         if (V_tcp_hostcache.purgeall) {
 714                 all = 1;
 715                 V_tcp_hostcache.purgeall = 0;
 716         }
 717
 718         tcp_hc_purge_internal(all);
 719
 720         callout_reset(&V_tcp_hc_callout, V_tcp_hostcache.prune * hz,
 721             tcp_hc_purge, arg);
 722         CURVNET_RESTORE();
 723 }
 724
 725 /*
 726  * Expire and purge all entries in hostcache immediately.
 727  */
 728 static int
 729 sysctl_tcp_hc_purgenow(SYSCTL_HANDLER_ARGS)
 730 {
 731         int error, val;
 732
 733         val = 0;
 734         error = sysctl_handle_int(oidp, &val, 0, req);
 735         if (error || !req->newptr)
 736                 return (error);
 737
 738         tcp_hc_purge_internal(1);
 739
 740         callout_reset(&V_tcp_hc_callout, V_tcp_hostcache.prune * hz,
 741             tcp_hc_purge, curvnet);
 742
 743         return (0);
 744 }