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/kernel.h>
  73 #include <sys/lock.h>
  74 #include <sys/mutex.h>
  75 #include <sys/malloc.h>
  76 #include <sys/sbuf.h>
  77 #include <sys/socket.h>
  78 #include <sys/socketvar.h>
  79 #include <sys/sysctl.h>
  80
  81 #include <net/if.h>
  82 #include <net/if_var.h>
  83 #include <net/route.h>
  84 #include <net/vnet.h>
  85
  86 #include <netinet/in.h>
  87 #include <netinet/in_systm.h>
  88 #include <netinet/ip.h>
  89 #include <netinet/in_var.h>
  90 #include <netinet/in_pcb.h>
  91 #include <netinet/ip_var.h>
  92 #ifdef INET6
  93 #include <netinet/ip6.h>
  94 #include <netinet6/ip6_var.h>
  95 #endif
  96 #include <netinet/tcp.h>
  97 #include <netinet/tcp_var.h>
  98 #include <netinet/tcp_hostcache.h>
  99 #ifdef INET6
 100 #include <netinet6/tcp6_var.h>
 101 #endif
 102
 103 #include <vm/uma.h>
 104
 105 /* Arbitrary values */
 106 #define TCP_HOSTCACHE_HASHSIZE          512
 107 #define TCP_HOSTCACHE_BUCKETLIMIT       30
 108 #define TCP_HOSTCACHE_EXPIRE            60*60   /* one hour */
 109 #define TCP_HOSTCACHE_PRUNE             5*60    /* every 5 minutes */
 110
 111 static VNET_DEFINE(struct tcp_hostcache, tcp_hostcache);
 112 #define V_tcp_hostcache         VNET(tcp_hostcache)
 113
 114 static VNET_DEFINE(struct callout, tcp_hc_callout);
 115 #define V_tcp_hc_callout        VNET(tcp_hc_callout)
 116
 117 static struct hc_metrics *tcp_hc_lookup(struct in_conninfo *);
 118 static struct hc_metrics *tcp_hc_insert(struct in_conninfo *);
 119 static int sysctl_tcp_hc_list(SYSCTL_HANDLER_ARGS);
 120 static int sysctl_tcp_hc_purgenow(SYSCTL_HANDLER_ARGS);
 121 static void tcp_hc_purge_internal(int);
 122 static void tcp_hc_purge(void *);
 123
 124 static SYSCTL_NODE(_net_inet_tcp, OID_AUTO, hostcache, CTLFLAG_RW, 0,
 125     "TCP Host cache");
 126
 127 VNET_DEFINE(int, tcp_use_hostcache) = 1;
 128 #define V_tcp_use_hostcache  VNET(tcp_use_hostcache)
 129 SYSCTL_INT(_net_inet_tcp_hostcache, OID_AUTO, enable, CTLFLAG_VNET | CTLFLAG_RW,
 130     &VNET_NAME(tcp_use_hostcache), 0,
 131     "Enable the TCP hostcache");
 132
 133 SYSCTL_UINT(_net_inet_tcp_hostcache, OID_AUTO, cachelimit, CTLFLAG_VNET | CTLFLAG_RDTUN,
 134     &VNET_NAME(tcp_hostcache.cache_limit), 0,
 135     "Overall entry limit for hostcache");
 136
 137 SYSCTL_UINT(_net_inet_tcp_hostcache, OID_AUTO, hashsize, CTLFLAG_VNET | CTLFLAG_RDTUN,
 138     &VNET_NAME(tcp_hostcache.hashsize), 0,
 139     "Size of TCP hostcache hashtable");
 140
 141 SYSCTL_UINT(_net_inet_tcp_hostcache, OID_AUTO, bucketlimit,
 142     CTLFLAG_VNET | CTLFLAG_RDTUN, &VNET_NAME(tcp_hostcache.bucket_limit), 0,
 143     "Per-bucket hash limit for hostcache");
 144
 145 SYSCTL_UINT(_net_inet_tcp_hostcache, OID_AUTO, count, CTLFLAG_VNET | CTLFLAG_RD,
 146      &VNET_NAME(tcp_hostcache.cache_count), 0,
 147     "Current number of entries in hostcache");
 148
 149 SYSCTL_INT(_net_inet_tcp_hostcache, OID_AUTO, expire, CTLFLAG_VNET | CTLFLAG_RW,
 150     &VNET_NAME(tcp_hostcache.expire), 0,
 151     "Expire time of TCP hostcache entries");
 152
 153 SYSCTL_INT(_net_inet_tcp_hostcache, OID_AUTO, prune, CTLFLAG_VNET | CTLFLAG_RW,
 154     &VNET_NAME(tcp_hostcache.prune), 0,
 155     "Time between purge runs");
 156
 157 SYSCTL_INT(_net_inet_tcp_hostcache, OID_AUTO, purge, CTLFLAG_VNET | CTLFLAG_RW,
 158     &VNET_NAME(tcp_hostcache.purgeall), 0,
 159     "Expire all entires on next purge run");
 160
 161 SYSCTL_PROC(_net_inet_tcp_hostcache, OID_AUTO, list,
 162     CTLTYPE_STRING | CTLFLAG_RD | CTLFLAG_SKIP, 0, 0,
 163     sysctl_tcp_hc_list, "A", "List of all hostcache entries");
 164
 165 SYSCTL_PROC(_net_inet_tcp_hostcache, OID_AUTO, purgenow,
 166     CTLTYPE_INT | CTLFLAG_RW, NULL, 0,
 167     sysctl_tcp_hc_purgenow, "I", "Immediately purge all entries");
 168
 169 static MALLOC_DEFINE(M_HOSTCACHE, "hostcache", "TCP hostcache");
 170
 171 #define HOSTCACHE_HASH(ip) \
 172         (((ip)->s_addr ^ ((ip)->s_addr >> 7) ^ ((ip)->s_addr >> 17)) &  \
 173           V_tcp_hostcache.hashmask)
 174
 175 /* XXX: What is the recommended hash to get good entropy for IPv6 addresses? */
 176 #define HOSTCACHE_HASH6(ip6)                            \
 177         (((ip6)->s6_addr32[0] ^                         \
 178           (ip6)->s6_addr32[1] ^                         \
 179           (ip6)->s6_addr32[2] ^                         \
 180           (ip6)->s6_addr32[3]) &                        \
 181          V_tcp_hostcache.hashmask)
 182
 183 #define THC_LOCK(lp)            mtx_lock(lp)
 184 #define THC_UNLOCK(lp)          mtx_unlock(lp)
 185
 186 void
 187 tcp_hc_init(void)
 188 {
 189         u_int cache_limit;
 190         int i;
 191
 192         /*
 193          * Initialize hostcache structures.
 194          */
 195         V_tcp_hostcache.cache_count = 0;
 196         V_tcp_hostcache.hashsize = TCP_HOSTCACHE_HASHSIZE;
 197         V_tcp_hostcache.bucket_limit = TCP_HOSTCACHE_BUCKETLIMIT;
 198         V_tcp_hostcache.expire = TCP_HOSTCACHE_EXPIRE;
 199         V_tcp_hostcache.prune = TCP_HOSTCACHE_PRUNE;
 200
 201         TUNABLE_INT_FETCH("net.inet.tcp.hostcache.hashsize",
 202             &V_tcp_hostcache.hashsize);
 203         if (!powerof2(V_tcp_hostcache.hashsize)) {
 204                 printf("WARNING: hostcache hash size is not a power of 2.\n");
 205                 V_tcp_hostcache.hashsize = TCP_HOSTCACHE_HASHSIZE; /* default */
 206         }
 207         V_tcp_hostcache.hashmask = V_tcp_hostcache.hashsize - 1;
 208
 209         TUNABLE_INT_FETCH("net.inet.tcp.hostcache.bucketlimit",
 210             &V_tcp_hostcache.bucket_limit);
 211
 212         cache_limit = V_tcp_hostcache.hashsize * V_tcp_hostcache.bucket_limit;
 213         V_tcp_hostcache.cache_limit = cache_limit;
 214         TUNABLE_INT_FETCH("net.inet.tcp.hostcache.cachelimit",
 215             &V_tcp_hostcache.cache_limit);
 216         if (V_tcp_hostcache.cache_limit > cache_limit)
 217                 V_tcp_hostcache.cache_limit = cache_limit;
 218
 219         /*
 220          * Allocate the hash table.
 221          */
 222         V_tcp_hostcache.hashbase = (struct hc_head *)
 223             malloc(V_tcp_hostcache.hashsize * sizeof(struct hc_head),
 224                    M_HOSTCACHE, M_WAITOK | M_ZERO);
 225
 226         /*
 227          * Initialize the hash buckets.
 228          */
 229         for (i = 0; i < V_tcp_hostcache.hashsize; i++) {
 230                 TAILQ_INIT(&V_tcp_hostcache.hashbase[i].hch_bucket);
 231                 V_tcp_hostcache.hashbase[i].hch_length = 0;
 232                 mtx_init(&V_tcp_hostcache.hashbase[i].hch_mtx, "tcp_hc_entry",
 233                           NULL, MTX_DEF);
 234         }
 235
 236         /*
 237          * Allocate the hostcache entries.
 238          */
 239         V_tcp_hostcache.zone =
 240             uma_zcreate("hostcache", sizeof(struct hc_metrics),
 241             NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, 0);
 242         uma_zone_set_max(V_tcp_hostcache.zone, V_tcp_hostcache.cache_limit);
 243
 244         /*
 245          * Set up periodic cache cleanup.
 246          */
 247         callout_init(&V_tcp_hc_callout, 1);
 248         callout_reset(&V_tcp_hc_callout, V_tcp_hostcache.prune * hz,
 249             tcp_hc_purge, curvnet);
 250 }
 251
 252 #ifdef VIMAGE
 253 void
 254 tcp_hc_destroy(void)
 255 {
 256         int i;
 257
 258         callout_drain(&V_tcp_hc_callout);
 259
 260         /* Purge all hc entries. */
 261         tcp_hc_purge_internal(1);
 262
 263         /* Free the uma zone and the allocated hash table. */
 264         uma_zdestroy(V_tcp_hostcache.zone);
 265
 266         for (i = 0; i < V_tcp_hostcache.hashsize; i++)
 267                 mtx_destroy(&V_tcp_hostcache.hashbase[i].hch_mtx);
 268         free(V_tcp_hostcache.hashbase, M_HOSTCACHE);
 269 }
 270 #endif
 271
 272 /*
 273  * Internal function: look up an entry in the hostcache or return NULL.
 274  *
 275  * If an entry has been returned, the caller becomes responsible for
 276  * unlocking the bucket row after he is done reading/modifying the entry.
 277  */
 278 static struct hc_metrics *
 279 tcp_hc_lookup(struct in_conninfo *inc)
 280 {
 281         int hash;
 282         struct hc_head *hc_head;
 283         struct hc_metrics *hc_entry;
 284
 285         if (!V_tcp_use_hostcache)
 286                 return NULL;
 287
 288         KASSERT(inc != NULL, ("tcp_hc_lookup with NULL in_conninfo pointer"));
 289
 290         /*
 291          * Hash the foreign ip address.
 292          */
 293         if (inc->inc_flags & INC_ISIPV6)
 294                 hash = HOSTCACHE_HASH6(&inc->inc6_faddr);
 295         else
 296                 hash = HOSTCACHE_HASH(&inc->inc_faddr);
 297
 298         hc_head = &V_tcp_hostcache.hashbase[hash];
 299
 300         /*
 301          * Acquire lock for this bucket row; we release the lock if we don't
 302          * find an entry, otherwise the caller has to unlock after he is
 303          * done.
 304          */
 305         THC_LOCK(&hc_head->hch_mtx);
 306
 307         /*
 308          * Iterate through entries in bucket row looking for a match.
 309          */
 310         TAILQ_FOREACH(hc_entry, &hc_head->hch_bucket, rmx_q) {
 311                 if (inc->inc_flags & INC_ISIPV6) {
 312                         /* XXX: check ip6_zoneid */
 313                         if (memcmp(&inc->inc6_faddr, &hc_entry->ip6,
 314                             sizeof(inc->inc6_faddr)) == 0)
 315                                 return hc_entry;
 316                 } else {
 317                         if (memcmp(&inc->inc_faddr, &hc_entry->ip4,
 318                             sizeof(inc->inc_faddr)) == 0)
 319                                 return hc_entry;
 320                 }
 321         }
 322
 323         /*
 324          * We were unsuccessful and didn't find anything.
 325          */
 326         THC_UNLOCK(&hc_head->hch_mtx);
 327         return NULL;
 328 }
 329
 330 /*
 331  * Internal function: insert an entry into the hostcache or return NULL if
 332  * unable to allocate a new one.
 333  *
 334  * If an entry has been returned, the caller becomes responsible for
 335  * unlocking the bucket row after he is done reading/modifying the entry.
 336  */
 337 static struct hc_metrics *
 338 tcp_hc_insert(struct in_conninfo *inc)
 339 {
 340         int hash;
 341         struct hc_head *hc_head;
 342         struct hc_metrics *hc_entry;
 343
 344         if (!V_tcp_use_hostcache)
 345                 return NULL;
 346
 347         KASSERT(inc != NULL, ("tcp_hc_insert with NULL in_conninfo pointer"));
 348
 349         /*
 350          * Hash the foreign ip address.
 351          */
 352         if (inc->inc_flags & INC_ISIPV6)
 353                 hash = HOSTCACHE_HASH6(&inc->inc6_faddr);
 354         else
 355                 hash = HOSTCACHE_HASH(&inc->inc_faddr);
 356
 357         hc_head = &V_tcp_hostcache.hashbase[hash];
 358
 359         /*
 360          * Acquire lock for this bucket row; we release the lock if we don't
 361          * find an entry, otherwise the caller has to unlock after he is
 362          * done.
 363          */
 364         THC_LOCK(&hc_head->hch_mtx);
 365
 366         /*
 367          * If the bucket limit is reached, reuse the least-used element.
 368          */
 369         if (hc_head->hch_length >= V_tcp_hostcache.bucket_limit ||
 370             V_tcp_hostcache.cache_count >= V_tcp_hostcache.cache_limit) {
 371                 hc_entry = TAILQ_LAST(&hc_head->hch_bucket, hc_qhead);
 372                 /*
 373                  * At first we were dropping the last element, just to
 374                  * reacquire it in the next two lines again, which isn't very
 375                  * efficient.  Instead just reuse the least used element.
 376                  * We may drop something that is still "in-use" but we can be
 377                  * "lossy".
 378                  * Just give up if this bucket row is empty and we don't have
 379                  * anything to replace.
 380                  */
 381                 if (hc_entry == NULL) {
 382                         THC_UNLOCK(&hc_head->hch_mtx);
 383                         return NULL;
 384                 }
 385                 TAILQ_REMOVE(&hc_head->hch_bucket, hc_entry, rmx_q);
 386                 V_tcp_hostcache.hashbase[hash].hch_length--;
 387                 V_tcp_hostcache.cache_count--;
 388                 TCPSTAT_INC(tcps_hc_bucketoverflow);
 389 #if 0
 390                 uma_zfree(V_tcp_hostcache.zone, hc_entry);
 391 #endif
 392         } else {
 393                 /*
 394                  * Allocate a new entry, or balk if not possible.
 395                  */
 396                 hc_entry = uma_zalloc(V_tcp_hostcache.zone, M_NOWAIT);
 397                 if (hc_entry == NULL) {
 398                         THC_UNLOCK(&hc_head->hch_mtx);
 399                         return NULL;
 400                 }
 401         }
 402
 403         /*
 404          * Initialize basic information of hostcache entry.
 405          */
 406         bzero(hc_entry, sizeof(*hc_entry));
 407         if (inc->inc_flags & INC_ISIPV6) {
 408                 hc_entry->ip6 = inc->inc6_faddr;
 409                 hc_entry->ip6_zoneid = inc->inc6_zoneid;
 410         } else
 411                 hc_entry->ip4 = inc->inc_faddr;
 412         hc_entry->rmx_head = hc_head;
 413         hc_entry->rmx_expire = V_tcp_hostcache.expire;
 414
 415         /*
 416          * Put it upfront.
 417          */
 418         TAILQ_INSERT_HEAD(&hc_head->hch_bucket, hc_entry, rmx_q);
 419         V_tcp_hostcache.hashbase[hash].hch_length++;
 420         V_tcp_hostcache.cache_count++;
 421         TCPSTAT_INC(tcps_hc_added);
 422
 423         return hc_entry;
 424 }
 425
 426 /*
 427  * External function: look up an entry in the hostcache and fill out the
 428  * supplied TCP metrics structure.  Fills in NULL when no entry was found or
 429  * a value is not set.
 430  */
 431 void
 432 tcp_hc_get(struct in_conninfo *inc, struct hc_metrics_lite *hc_metrics_lite)
 433 {
 434         struct hc_metrics *hc_entry;
 435
 436         if (!V_tcp_use_hostcache)
 437                 return;
 438
 439         /*
 440          * Find the right bucket.
 441          */
 442         hc_entry = tcp_hc_lookup(inc);
 443
 444         /*
 445          * If we don't have an existing object.
 446          */
 447         if (hc_entry == NULL) {
 448                 bzero(hc_metrics_lite, sizeof(*hc_metrics_lite));
 449                 return;
 450         }
 451         hc_entry->rmx_hits++;
 452         hc_entry->rmx_expire = V_tcp_hostcache.expire; /* start over again */
 453
 454         hc_metrics_lite->rmx_mtu = hc_entry->rmx_mtu;
 455         hc_metrics_lite->rmx_ssthresh = hc_entry->rmx_ssthresh;
 456         hc_metrics_lite->rmx_rtt = hc_entry->rmx_rtt;
 457         hc_metrics_lite->rmx_rttvar = hc_entry->rmx_rttvar;
 458         hc_metrics_lite->rmx_cwnd = hc_entry->rmx_cwnd;
 459         hc_metrics_lite->rmx_sendpipe = hc_entry->rmx_sendpipe;
 460         hc_metrics_lite->rmx_recvpipe = hc_entry->rmx_recvpipe;
 461
 462         /*
 463          * Unlock bucket row.
 464          */
 465         THC_UNLOCK(&hc_entry->rmx_head->hch_mtx);
 466 }
 467
 468 /*
 469  * External function: look up an entry in the hostcache and return the
 470  * discovered path MTU.  Returns 0 if no entry is found or value is not
 471  * set.
 472  */
 473 uint32_t
 474 tcp_hc_getmtu(struct in_conninfo *inc)
 475 {
 476         struct hc_metrics *hc_entry;
 477         uint32_t mtu;
 478
 479         if (!V_tcp_use_hostcache)
 480                 return 0;
 481
 482         hc_entry = tcp_hc_lookup(inc);
 483         if (hc_entry == NULL) {
 484                 return 0;
 485         }
 486         hc_entry->rmx_hits++;
 487         hc_entry->rmx_expire = V_tcp_hostcache.expire; /* start over again */
 488
 489         mtu = hc_entry->rmx_mtu;
 490         THC_UNLOCK(&hc_entry->rmx_head->hch_mtx);
 491         return mtu;
 492 }
 493
 494 /*
 495  * External function: update the MTU value of an entry in the hostcache.
 496  * Creates a new entry if none was found.
 497  */
 498 void
 499 tcp_hc_updatemtu(struct in_conninfo *inc, uint32_t mtu)
 500 {
 501         struct hc_metrics *hc_entry;
 502
 503         if (!V_tcp_use_hostcache)
 504                 return;
 505
 506         /*
 507          * Find the right bucket.
 508          */
 509         hc_entry = tcp_hc_lookup(inc);
 510
 511         /*
 512          * If we don't have an existing object, try to insert a new one.
 513          */
 514         if (hc_entry == NULL) {
 515                 hc_entry = tcp_hc_insert(inc);
 516                 if (hc_entry == NULL)
 517                         return;
 518         }
 519         hc_entry->rmx_updates++;
 520         hc_entry->rmx_expire = V_tcp_hostcache.expire; /* start over again */
 521
 522         hc_entry->rmx_mtu = mtu;
 523
 524         /*
 525          * Put it upfront so we find it faster next time.
 526          */
 527         TAILQ_REMOVE(&hc_entry->rmx_head->hch_bucket, hc_entry, rmx_q);
 528         TAILQ_INSERT_HEAD(&hc_entry->rmx_head->hch_bucket, hc_entry, rmx_q);
 529
 530         /*
 531          * Unlock bucket row.
 532          */
 533         THC_UNLOCK(&hc_entry->rmx_head->hch_mtx);
 534 }
 535
 536 /*
 537  * External function: update the TCP metrics of an entry in the hostcache.
 538  * Creates a new entry if none was found.
 539  */
 540 void
 541 tcp_hc_update(struct in_conninfo *inc, struct hc_metrics_lite *hcml)
 542 {
 543         struct hc_metrics *hc_entry;
 544
 545         if (!V_tcp_use_hostcache)
 546                 return;
 547
 548         hc_entry = tcp_hc_lookup(inc);
 549         if (hc_entry == NULL) {
 550                 hc_entry = tcp_hc_insert(inc);
 551                 if (hc_entry == NULL)
 552                         return;
 553         }
 554         hc_entry->rmx_updates++;
 555         hc_entry->rmx_expire = V_tcp_hostcache.expire; /* start over again */
 556
 557         if (hcml->rmx_rtt != 0) {
 558                 if (hc_entry->rmx_rtt == 0)
 559                         hc_entry->rmx_rtt = hcml->rmx_rtt;
 560                 else
 561                         hc_entry->rmx_rtt = ((uint64_t)hc_entry->rmx_rtt +
 562                             (uint64_t)hcml->rmx_rtt) / 2;
 563                 TCPSTAT_INC(tcps_cachedrtt);
 564         }
 565         if (hcml->rmx_rttvar != 0) {
 566                 if (hc_entry->rmx_rttvar == 0)
 567                         hc_entry->rmx_rttvar = hcml->rmx_rttvar;
 568                 else
 569                         hc_entry->rmx_rttvar = ((uint64_t)hc_entry->rmx_rttvar +
 570                             (uint64_t)hcml->rmx_rttvar) / 2;
 571                 TCPSTAT_INC(tcps_cachedrttvar);
 572         }
 573         if (hcml->rmx_ssthresh != 0) {
 574                 if (hc_entry->rmx_ssthresh == 0)
 575                         hc_entry->rmx_ssthresh = hcml->rmx_ssthresh;
 576                 else
 577                         hc_entry->rmx_ssthresh =
 578                             (hc_entry->rmx_ssthresh + hcml->rmx_ssthresh) / 2;
 579                 TCPSTAT_INC(tcps_cachedssthresh);
 580         }
 581         if (hcml->rmx_cwnd != 0) {
 582                 if (hc_entry->rmx_cwnd == 0)
 583                         hc_entry->rmx_cwnd = hcml->rmx_cwnd;
 584                 else
 585                         hc_entry->rmx_cwnd = ((uint64_t)hc_entry->rmx_cwnd +
 586                             (uint64_t)hcml->rmx_cwnd) / 2;
 587                 /* TCPSTAT_INC(tcps_cachedcwnd); */
 588         }
 589         if (hcml->rmx_sendpipe != 0) {
 590                 if (hc_entry->rmx_sendpipe == 0)
 591                         hc_entry->rmx_sendpipe = hcml->rmx_sendpipe;
 592                 else
 593                         hc_entry->rmx_sendpipe =
 594                             ((uint64_t)hc_entry->rmx_sendpipe +
 595                             (uint64_t)hcml->rmx_sendpipe) /2;
 596                 /* TCPSTAT_INC(tcps_cachedsendpipe); */
 597         }
 598         if (hcml->rmx_recvpipe != 0) {
 599                 if (hc_entry->rmx_recvpipe == 0)
 600                         hc_entry->rmx_recvpipe = hcml->rmx_recvpipe;
 601                 else
 602                         hc_entry->rmx_recvpipe =
 603                             ((uint64_t)hc_entry->rmx_recvpipe +
 604                             (uint64_t)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 #ifdef INET6
 625         char ip6buf[INET6_ADDRSTRLEN];
 626 #endif
 627
 628         sbuf_new(&sb, NULL, linesize * (V_tcp_hostcache.cache_count + 1),
 629                 SBUF_INCLUDENUL);
 630
 631         sbuf_printf(&sb,
 632                 "\nIP address        MTU  SSTRESH      RTT   RTTVAR "
 633                 "    CWND SENDPIPE RECVPIPE HITS  UPD  EXP\n");
 634
 635 #define msec(u) (((u) + 500) / 1000)
 636         for (i = 0; i < V_tcp_hostcache.hashsize; i++) {
 637                 THC_LOCK(&V_tcp_hostcache.hashbase[i].hch_mtx);
 638                 TAILQ_FOREACH(hc_entry, &V_tcp_hostcache.hashbase[i].hch_bucket,
 639                               rmx_q) {
 640                         sbuf_printf(&sb,
 641                             "%-15s %5u %8u %6lums %6lums %8u %8u %8u %4lu "
 642                             "%4lu %4i\n",
 643                             hc_entry->ip4.s_addr ? inet_ntoa(hc_entry->ip4) :
 644 #ifdef INET6
 645                                 ip6_sprintf(ip6buf, &hc_entry->ip6),
 646 #else
 647                                 "IPv6?",
 648 #endif
 649                             hc_entry->rmx_mtu,
 650                             hc_entry->rmx_ssthresh,
 651                             msec((u_long)hc_entry->rmx_rtt *
 652                                 (RTM_RTTUNIT / (hz * TCP_RTT_SCALE))),
 653                             msec((u_long)hc_entry->rmx_rttvar *
 654                                 (RTM_RTTUNIT / (hz * TCP_RTTVAR_SCALE))),
 655                             hc_entry->rmx_cwnd,
 656                             hc_entry->rmx_sendpipe,
 657                             hc_entry->rmx_recvpipe,
 658                             hc_entry->rmx_hits,
 659                             hc_entry->rmx_updates,
 660                             hc_entry->rmx_expire);
 661                 }
 662                 THC_UNLOCK(&V_tcp_hostcache.hashbase[i].hch_mtx);
 663         }
 664 #undef msec
 665         error = sbuf_finish(&sb);
 666         if (error == 0)
 667                 error = SYSCTL_OUT(req, sbuf_data(&sb), sbuf_len(&sb));
 668         sbuf_delete(&sb);
 669         return(error);
 670 }
 671
 672 /*
 673  * Caller has to make sure the curvnet is set properly.
 674  */
 675 static void
 676 tcp_hc_purge_internal(int all)
 677 {
 678         struct hc_metrics *hc_entry, *hc_next;
 679         int i;
 680
 681         for (i = 0; i < V_tcp_hostcache.hashsize; i++) {
 682                 THC_LOCK(&V_tcp_hostcache.hashbase[i].hch_mtx);
 683                 TAILQ_FOREACH_SAFE(hc_entry,
 684                     &V_tcp_hostcache.hashbase[i].hch_bucket, rmx_q, hc_next) {
 685                         if (all || hc_entry->rmx_expire <= 0) {
 686                                 TAILQ_REMOVE(&V_tcp_hostcache.hashbase[i].hch_bucket,
 687                                               hc_entry, rmx_q);
 688                                 uma_zfree(V_tcp_hostcache.zone, hc_entry);
 689                                 V_tcp_hostcache.hashbase[i].hch_length--;
 690                                 V_tcp_hostcache.cache_count--;
 691                         } else
 692                                 hc_entry->rmx_expire -= V_tcp_hostcache.prune;
 693                 }
 694                 THC_UNLOCK(&V_tcp_hostcache.hashbase[i].hch_mtx);
 695         }
 696 }
 697
 698 /*
 699  * Expire and purge (old|all) entries in the tcp_hostcache.  Runs
 700  * periodically from the callout.
 701  */
 702 static void
 703 tcp_hc_purge(void *arg)
 704 {
 705         CURVNET_SET((struct vnet *) arg);
 706         int all = 0;
 707
 708         if (V_tcp_hostcache.purgeall) {
 709                 all = 1;
 710                 V_tcp_hostcache.purgeall = 0;
 711         }
 712
 713         tcp_hc_purge_internal(all);
 714
 715         callout_reset(&V_tcp_hc_callout, V_tcp_hostcache.prune * hz,
 716             tcp_hc_purge, arg);
 717         CURVNET_RESTORE();
 718 }
 719
 720 /*
 721  * Expire and purge all entries in hostcache immediately.
 722  */
 723 static int
 724 sysctl_tcp_hc_purgenow(SYSCTL_HANDLER_ARGS)
 725 {
 726         int error, val;
 727
 728         val = 0;
 729         error = sysctl_handle_int(oidp, &val, 0, req);
 730         if (error || !req->newptr)
 731                 return (error);
 732
 733         tcp_hc_purge_internal(1);
 734
 735         callout_reset(&V_tcp_hc_callout, V_tcp_hostcache.prune * hz,
 736             tcp_hc_purge, curvnet);
 737
 738         return (0);
 739 }