tcp_hostcache.c revision 195699
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, bandwidth, max 36 * MTU, 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: head/sys/netinet/tcp_hostcache.c 195699 2009-07-14 22:48:30Z rwatson $"); 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/socket.h> 77#include <sys/socketvar.h> 78#include <sys/sysctl.h> 79#include <sys/vimage.h> 80 81#include <net/if.h> 82#include <net/route.h> 83 84#include <netinet/in.h> 85#include <netinet/in_systm.h> 86#include <netinet/ip.h> 87#include <netinet/in_var.h> 88#include <netinet/in_pcb.h> 89#include <netinet/ip_var.h> 90#ifdef INET6 91#include <netinet/ip6.h> 92#include <netinet6/ip6_var.h> 93#endif 94#include <netinet/tcp.h> 95#include <netinet/tcp_var.h> 96#include <netinet/tcp_hostcache.h> 97#ifdef INET6 98#include <netinet6/tcp6_var.h> 99#endif 100 101#include <vm/uma.h> 102 103/* Arbitrary values */ 104#define TCP_HOSTCACHE_HASHSIZE 512 105#define TCP_HOSTCACHE_BUCKETLIMIT 30 106#define TCP_HOSTCACHE_EXPIRE 60*60 /* one hour */ 107#define TCP_HOSTCACHE_PRUNE 5*60 /* every 5 minutes */ 108 109static VNET_DEFINE(struct tcp_hostcache, tcp_hostcache); 110static VNET_DEFINE(struct callout, tcp_hc_callout); 111 112#define V_tcp_hostcache VNET_GET(tcp_hostcache) 113#define V_tcp_hc_callout VNET_GET(tcp_hc_callout) 114 115static struct hc_metrics *tcp_hc_lookup(struct in_conninfo *); 116static struct hc_metrics *tcp_hc_insert(struct in_conninfo *); 117static int sysctl_tcp_hc_list(SYSCTL_HANDLER_ARGS); 118static void tcp_hc_purge(void *); 119 120SYSCTL_NODE(_net_inet_tcp, OID_AUTO, hostcache, CTLFLAG_RW, 0, 121 "TCP Host cache"); 122 123SYSCTL_VNET_INT(_net_inet_tcp_hostcache, OID_AUTO, cachelimit, CTLFLAG_RDTUN, 124 &VNET_NAME(tcp_hostcache.cache_limit), 0, 125 "Overall entry limit for hostcache"); 126 127SYSCTL_VNET_INT(_net_inet_tcp_hostcache, OID_AUTO, hashsize, CTLFLAG_RDTUN, 128 &VNET_NAME(tcp_hostcache.hashsize), 0, 129 "Size of TCP hostcache hashtable"); 130 131SYSCTL_VNET_INT(_net_inet_tcp_hostcache, OID_AUTO, bucketlimit, 132 CTLFLAG_RDTUN, &VNET_NAME(tcp_hostcache.bucket_limit), 0, 133 "Per-bucket hash limit for hostcache"); 134 135SYSCTL_VNET_INT(_net_inet_tcp_hostcache, OID_AUTO, count, CTLFLAG_RD, 136 &VNET_NAME(tcp_hostcache.cache_count), 0, 137 "Current number of entries in hostcache"); 138 139SYSCTL_VNET_INT(_net_inet_tcp_hostcache, OID_AUTO, expire, CTLFLAG_RW, 140 &VNET_NAME(tcp_hostcache.expire), 0, 141 "Expire time of TCP hostcache entries"); 142 143SYSCTL_VNET_INT(_net_inet_tcp_hostcache, OID_AUTO, prune, CTLFLAG_RW, 144 &VNET_NAME(tcp_hostcache.prune), 0, 145 "Time between purge runs"); 146 147SYSCTL_VNET_INT(_net_inet_tcp_hostcache, OID_AUTO, purge, CTLFLAG_RW, 148 &VNET_NAME(tcp_hostcache.purgeall), 0, 149 "Expire all entires on next purge run"); 150 151SYSCTL_PROC(_net_inet_tcp_hostcache, OID_AUTO, list, 152 CTLTYPE_STRING | CTLFLAG_RD | CTLFLAG_SKIP, 0, 0, 153 sysctl_tcp_hc_list, "A", "List of all hostcache entries"); 154 155 156static MALLOC_DEFINE(M_HOSTCACHE, "hostcache", "TCP hostcache"); 157 158#define HOSTCACHE_HASH(ip) \ 159 (((ip)->s_addr ^ ((ip)->s_addr >> 7) ^ ((ip)->s_addr >> 17)) & \ 160 V_tcp_hostcache.hashmask) 161 162/* XXX: What is the recommended hash to get good entropy for IPv6 addresses? */ 163#define HOSTCACHE_HASH6(ip6) \ 164 (((ip6)->s6_addr32[0] ^ \ 165 (ip6)->s6_addr32[1] ^ \ 166 (ip6)->s6_addr32[2] ^ \ 167 (ip6)->s6_addr32[3]) & \ 168 V_tcp_hostcache.hashmask) 169 170#define THC_LOCK(lp) mtx_lock(lp) 171#define THC_UNLOCK(lp) mtx_unlock(lp) 172 173void 174tcp_hc_init(void) 175{ 176 int i; 177 178 /* 179 * Initialize hostcache structures. 180 */ 181 V_tcp_hostcache.cache_count = 0; 182 V_tcp_hostcache.hashsize = TCP_HOSTCACHE_HASHSIZE; 183 V_tcp_hostcache.bucket_limit = TCP_HOSTCACHE_BUCKETLIMIT; 184 V_tcp_hostcache.cache_limit = 185 V_tcp_hostcache.hashsize * V_tcp_hostcache.bucket_limit; 186 V_tcp_hostcache.expire = TCP_HOSTCACHE_EXPIRE; 187 V_tcp_hostcache.prune = TCP_HOSTCACHE_PRUNE; 188 189 TUNABLE_INT_FETCH("net.inet.tcp.hostcache.hashsize", 190 &V_tcp_hostcache.hashsize); 191 TUNABLE_INT_FETCH("net.inet.tcp.hostcache.cachelimit", 192 &V_tcp_hostcache.cache_limit); 193 TUNABLE_INT_FETCH("net.inet.tcp.hostcache.bucketlimit", 194 &V_tcp_hostcache.bucket_limit); 195 if (!powerof2(V_tcp_hostcache.hashsize)) { 196 printf("WARNING: hostcache hash size is not a power of 2.\n"); 197 V_tcp_hostcache.hashsize = TCP_HOSTCACHE_HASHSIZE; /* default */ 198 } 199 V_tcp_hostcache.hashmask = V_tcp_hostcache.hashsize - 1; 200 201 /* 202 * Allocate the hash table. 203 */ 204 V_tcp_hostcache.hashbase = (struct hc_head *) 205 malloc(V_tcp_hostcache.hashsize * sizeof(struct hc_head), 206 M_HOSTCACHE, M_WAITOK | M_ZERO); 207 208 /* 209 * Initialize the hash buckets. 210 */ 211 for (i = 0; i < V_tcp_hostcache.hashsize; i++) { 212 TAILQ_INIT(&V_tcp_hostcache.hashbase[i].hch_bucket); 213 V_tcp_hostcache.hashbase[i].hch_length = 0; 214 mtx_init(&V_tcp_hostcache.hashbase[i].hch_mtx, "tcp_hc_entry", 215 NULL, MTX_DEF); 216 } 217 218 /* 219 * Allocate the hostcache entries. 220 */ 221 V_tcp_hostcache.zone = 222 uma_zcreate("hostcache", sizeof(struct hc_metrics), 223 NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, 0); 224 uma_zone_set_max(V_tcp_hostcache.zone, V_tcp_hostcache.cache_limit); 225 226 /* 227 * Set up periodic cache cleanup. 228 */ 229 callout_init(&V_tcp_hc_callout, CALLOUT_MPSAFE); 230 callout_reset(&V_tcp_hc_callout, V_tcp_hostcache.prune * hz, 231 tcp_hc_purge, curvnet); 232} 233 234#ifdef VIMAGE 235void 236tcp_hc_destroy(void) 237{ 238 239 /* XXX TODO walk the hashtable and free all entries */ 240 241 callout_drain(&V_tcp_hc_callout); 242} 243#endif 244 245/* 246 * Internal function: look up an entry in the hostcache or return NULL. 247 * 248 * If an entry has been returned, the caller becomes responsible for 249 * unlocking the bucket row after he is done reading/modifying the entry. 250 */ 251static struct hc_metrics * 252tcp_hc_lookup(struct in_conninfo *inc) 253{ 254 int hash; 255 struct hc_head *hc_head; 256 struct hc_metrics *hc_entry; 257 258 KASSERT(inc != NULL, ("tcp_hc_lookup with NULL in_conninfo pointer")); 259 260 /* 261 * Hash the foreign ip address. 262 */ 263 if (inc->inc_flags & INC_ISIPV6) 264 hash = HOSTCACHE_HASH6(&inc->inc6_faddr); 265 else 266 hash = HOSTCACHE_HASH(&inc->inc_faddr); 267 268 hc_head = &V_tcp_hostcache.hashbase[hash]; 269 270 /* 271 * Acquire lock for this bucket row; we release the lock if we don't 272 * find an entry, otherwise the caller has to unlock after he is 273 * done. 274 */ 275 THC_LOCK(&hc_head->hch_mtx); 276 277 /* 278 * Iterate through entries in bucket row looking for a match. 279 */ 280 TAILQ_FOREACH(hc_entry, &hc_head->hch_bucket, rmx_q) { 281 if (inc->inc_flags & INC_ISIPV6) { 282 if (memcmp(&inc->inc6_faddr, &hc_entry->ip6, 283 sizeof(inc->inc6_faddr)) == 0) 284 return hc_entry; 285 } else { 286 if (memcmp(&inc->inc_faddr, &hc_entry->ip4, 287 sizeof(inc->inc_faddr)) == 0) 288 return hc_entry; 289 } 290 } 291 292 /* 293 * We were unsuccessful and didn't find anything. 294 */ 295 THC_UNLOCK(&hc_head->hch_mtx); 296 return NULL; 297} 298 299/* 300 * Internal function: insert an entry into the hostcache or return NULL if 301 * unable to allocate a new one. 302 * 303 * If an entry has been returned, the caller becomes responsible for 304 * unlocking the bucket row after he is done reading/modifying the entry. 305 */ 306static struct hc_metrics * 307tcp_hc_insert(struct in_conninfo *inc) 308{ 309 int hash; 310 struct hc_head *hc_head; 311 struct hc_metrics *hc_entry; 312 313 KASSERT(inc != NULL, ("tcp_hc_insert with NULL in_conninfo pointer")); 314 315 /* 316 * Hash the foreign ip address. 317 */ 318 if (inc->inc_flags & INC_ISIPV6) 319 hash = HOSTCACHE_HASH6(&inc->inc6_faddr); 320 else 321 hash = HOSTCACHE_HASH(&inc->inc_faddr); 322 323 hc_head = &V_tcp_hostcache.hashbase[hash]; 324 325 /* 326 * Acquire lock for this bucket row; we release the lock if we don't 327 * find an entry, otherwise the caller has to unlock after he is 328 * done. 329 */ 330 THC_LOCK(&hc_head->hch_mtx); 331 332 /* 333 * If the bucket limit is reached, reuse the least-used element. 334 */ 335 if (hc_head->hch_length >= V_tcp_hostcache.bucket_limit || 336 V_tcp_hostcache.cache_count >= V_tcp_hostcache.cache_limit) { 337 hc_entry = TAILQ_LAST(&hc_head->hch_bucket, hc_qhead); 338 /* 339 * At first we were dropping the last element, just to 340 * reacquire it in the next two lines again, which isn't very 341 * efficient. Instead just reuse the least used element. 342 * We may drop something that is still "in-use" but we can be 343 * "lossy". 344 * Just give up if this bucket row is empty and we don't have 345 * anything to replace. 346 */ 347 if (hc_entry == NULL) { 348 THC_UNLOCK(&hc_head->hch_mtx); 349 return NULL; 350 } 351 TAILQ_REMOVE(&hc_head->hch_bucket, hc_entry, rmx_q); 352 V_tcp_hostcache.hashbase[hash].hch_length--; 353 V_tcp_hostcache.cache_count--; 354 TCPSTAT_INC(tcps_hc_bucketoverflow); 355#if 0 356 uma_zfree(V_tcp_hostcache.zone, hc_entry); 357#endif 358 } else { 359 /* 360 * Allocate a new entry, or balk if not possible. 361 */ 362 hc_entry = uma_zalloc(V_tcp_hostcache.zone, M_NOWAIT); 363 if (hc_entry == NULL) { 364 THC_UNLOCK(&hc_head->hch_mtx); 365 return NULL; 366 } 367 } 368 369 /* 370 * Initialize basic information of hostcache entry. 371 */ 372 bzero(hc_entry, sizeof(*hc_entry)); 373 if (inc->inc_flags & INC_ISIPV6) 374 bcopy(&inc->inc6_faddr, &hc_entry->ip6, sizeof(hc_entry->ip6)); 375 else 376 hc_entry->ip4 = inc->inc_faddr; 377 hc_entry->rmx_head = hc_head; 378 hc_entry->rmx_expire = V_tcp_hostcache.expire; 379 380 /* 381 * Put it upfront. 382 */ 383 TAILQ_INSERT_HEAD(&hc_head->hch_bucket, hc_entry, rmx_q); 384 V_tcp_hostcache.hashbase[hash].hch_length++; 385 V_tcp_hostcache.cache_count++; 386 TCPSTAT_INC(tcps_hc_added); 387 388 return hc_entry; 389} 390 391/* 392 * External function: look up an entry in the hostcache and fill out the 393 * supplied TCP metrics structure. Fills in NULL when no entry was found or 394 * a value is not set. 395 */ 396void 397tcp_hc_get(struct in_conninfo *inc, struct hc_metrics_lite *hc_metrics_lite) 398{ 399 struct hc_metrics *hc_entry; 400 401 /* 402 * Find the right bucket. 403 */ 404 hc_entry = tcp_hc_lookup(inc); 405 406 /* 407 * If we don't have an existing object. 408 */ 409 if (hc_entry == NULL) { 410 bzero(hc_metrics_lite, sizeof(*hc_metrics_lite)); 411 return; 412 } 413 hc_entry->rmx_hits++; 414 hc_entry->rmx_expire = V_tcp_hostcache.expire; /* start over again */ 415 416 hc_metrics_lite->rmx_mtu = hc_entry->rmx_mtu; 417 hc_metrics_lite->rmx_ssthresh = hc_entry->rmx_ssthresh; 418 hc_metrics_lite->rmx_rtt = hc_entry->rmx_rtt; 419 hc_metrics_lite->rmx_rttvar = hc_entry->rmx_rttvar; 420 hc_metrics_lite->rmx_bandwidth = hc_entry->rmx_bandwidth; 421 hc_metrics_lite->rmx_cwnd = hc_entry->rmx_cwnd; 422 hc_metrics_lite->rmx_sendpipe = hc_entry->rmx_sendpipe; 423 hc_metrics_lite->rmx_recvpipe = hc_entry->rmx_recvpipe; 424 425 /* 426 * Unlock bucket row. 427 */ 428 THC_UNLOCK(&hc_entry->rmx_head->hch_mtx); 429} 430 431/* 432 * External function: look up an entry in the hostcache and return the 433 * discovered path MTU. Returns NULL if no entry is found or value is not 434 * set. 435 */ 436u_long 437tcp_hc_getmtu(struct in_conninfo *inc) 438{ 439 struct hc_metrics *hc_entry; 440 u_long mtu; 441 442 hc_entry = tcp_hc_lookup(inc); 443 if (hc_entry == NULL) { 444 return 0; 445 } 446 hc_entry->rmx_hits++; 447 hc_entry->rmx_expire = V_tcp_hostcache.expire; /* start over again */ 448 449 mtu = hc_entry->rmx_mtu; 450 THC_UNLOCK(&hc_entry->rmx_head->hch_mtx); 451 return mtu; 452} 453 454/* 455 * External function: update the MTU value of an entry in the hostcache. 456 * Creates a new entry if none was found. 457 */ 458void 459tcp_hc_updatemtu(struct in_conninfo *inc, u_long mtu) 460{ 461 struct hc_metrics *hc_entry; 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, try to insert a new one. 470 */ 471 if (hc_entry == NULL) { 472 hc_entry = tcp_hc_insert(inc); 473 if (hc_entry == NULL) 474 return; 475 } 476 hc_entry->rmx_updates++; 477 hc_entry->rmx_expire = V_tcp_hostcache.expire; /* start over again */ 478 479 hc_entry->rmx_mtu = mtu; 480 481 /* 482 * Put it upfront so we find it faster next time. 483 */ 484 TAILQ_REMOVE(&hc_entry->rmx_head->hch_bucket, hc_entry, rmx_q); 485 TAILQ_INSERT_HEAD(&hc_entry->rmx_head->hch_bucket, hc_entry, rmx_q); 486 487 /* 488 * Unlock bucket row. 489 */ 490 THC_UNLOCK(&hc_entry->rmx_head->hch_mtx); 491} 492 493/* 494 * External function: update the TCP metrics of an entry in the hostcache. 495 * Creates a new entry if none was found. 496 */ 497void 498tcp_hc_update(struct in_conninfo *inc, struct hc_metrics_lite *hcml) 499{ 500 struct hc_metrics *hc_entry; 501 502 hc_entry = tcp_hc_lookup(inc); 503 if (hc_entry == NULL) { 504 hc_entry = tcp_hc_insert(inc); 505 if (hc_entry == NULL) 506 return; 507 } 508 hc_entry->rmx_updates++; 509 hc_entry->rmx_expire = V_tcp_hostcache.expire; /* start over again */ 510 511 if (hcml->rmx_rtt != 0) { 512 if (hc_entry->rmx_rtt == 0) 513 hc_entry->rmx_rtt = hcml->rmx_rtt; 514 else 515 hc_entry->rmx_rtt = 516 (hc_entry->rmx_rtt + hcml->rmx_rtt) / 2; 517 TCPSTAT_INC(tcps_cachedrtt); 518 } 519 if (hcml->rmx_rttvar != 0) { 520 if (hc_entry->rmx_rttvar == 0) 521 hc_entry->rmx_rttvar = hcml->rmx_rttvar; 522 else 523 hc_entry->rmx_rttvar = 524 (hc_entry->rmx_rttvar + hcml->rmx_rttvar) / 2; 525 TCPSTAT_INC(tcps_cachedrttvar); 526 } 527 if (hcml->rmx_ssthresh != 0) { 528 if (hc_entry->rmx_ssthresh == 0) 529 hc_entry->rmx_ssthresh = hcml->rmx_ssthresh; 530 else 531 hc_entry->rmx_ssthresh = 532 (hc_entry->rmx_ssthresh + hcml->rmx_ssthresh) / 2; 533 TCPSTAT_INC(tcps_cachedssthresh); 534 } 535 if (hcml->rmx_bandwidth != 0) { 536 if (hc_entry->rmx_bandwidth == 0) 537 hc_entry->rmx_bandwidth = hcml->rmx_bandwidth; 538 else 539 hc_entry->rmx_bandwidth = 540 (hc_entry->rmx_bandwidth + hcml->rmx_bandwidth) / 2; 541 /* TCPSTAT_INC(tcps_cachedbandwidth); */ 542 } 543 if (hcml->rmx_cwnd != 0) { 544 if (hc_entry->rmx_cwnd == 0) 545 hc_entry->rmx_cwnd = hcml->rmx_cwnd; 546 else 547 hc_entry->rmx_cwnd = 548 (hc_entry->rmx_cwnd + hcml->rmx_cwnd) / 2; 549 /* TCPSTAT_INC(tcps_cachedcwnd); */ 550 } 551 if (hcml->rmx_sendpipe != 0) { 552 if (hc_entry->rmx_sendpipe == 0) 553 hc_entry->rmx_sendpipe = hcml->rmx_sendpipe; 554 else 555 hc_entry->rmx_sendpipe = 556 (hc_entry->rmx_sendpipe + hcml->rmx_sendpipe) /2; 557 /* TCPSTAT_INC(tcps_cachedsendpipe); */ 558 } 559 if (hcml->rmx_recvpipe != 0) { 560 if (hc_entry->rmx_recvpipe == 0) 561 hc_entry->rmx_recvpipe = hcml->rmx_recvpipe; 562 else 563 hc_entry->rmx_recvpipe = 564 (hc_entry->rmx_recvpipe + hcml->rmx_recvpipe) /2; 565 /* TCPSTAT_INC(tcps_cachedrecvpipe); */ 566 } 567 568 TAILQ_REMOVE(&hc_entry->rmx_head->hch_bucket, hc_entry, rmx_q); 569 TAILQ_INSERT_HEAD(&hc_entry->rmx_head->hch_bucket, hc_entry, rmx_q); 570 THC_UNLOCK(&hc_entry->rmx_head->hch_mtx); 571} 572 573/* 574 * Sysctl function: prints the list and values of all hostcache entries in 575 * unsorted order. 576 */ 577static int 578sysctl_tcp_hc_list(SYSCTL_HANDLER_ARGS) 579{ 580 int bufsize; 581 int linesize = 128; 582 char *p, *buf; 583 int len, i, error; 584 struct hc_metrics *hc_entry; 585#ifdef INET6 586 char ip6buf[INET6_ADDRSTRLEN]; 587#endif 588 589 bufsize = linesize * (V_tcp_hostcache.cache_count + 1); 590 591 p = buf = (char *)malloc(bufsize, M_TEMP, M_WAITOK|M_ZERO); 592 593 len = snprintf(p, linesize, 594 "\nIP address MTU SSTRESH RTT RTTVAR BANDWIDTH " 595 " CWND SENDPIPE RECVPIPE HITS UPD EXP\n"); 596 p += len; 597 598#define msec(u) (((u) + 500) / 1000) 599 for (i = 0; i < V_tcp_hostcache.hashsize; i++) { 600 THC_LOCK(&V_tcp_hostcache.hashbase[i].hch_mtx); 601 TAILQ_FOREACH(hc_entry, &V_tcp_hostcache.hashbase[i].hch_bucket, 602 rmx_q) { 603 len = snprintf(p, linesize, 604 "%-15s %5lu %8lu %6lums %6lums %9lu %8lu %8lu %8lu " 605 "%4lu %4lu %4i\n", 606 hc_entry->ip4.s_addr ? inet_ntoa(hc_entry->ip4) : 607#ifdef INET6 608 ip6_sprintf(ip6buf, &hc_entry->ip6), 609#else 610 "IPv6?", 611#endif 612 hc_entry->rmx_mtu, 613 hc_entry->rmx_ssthresh, 614 msec(hc_entry->rmx_rtt * 615 (RTM_RTTUNIT / (hz * TCP_RTT_SCALE))), 616 msec(hc_entry->rmx_rttvar * 617 (RTM_RTTUNIT / (hz * TCP_RTT_SCALE))), 618 hc_entry->rmx_bandwidth * 8, 619 hc_entry->rmx_cwnd, 620 hc_entry->rmx_sendpipe, 621 hc_entry->rmx_recvpipe, 622 hc_entry->rmx_hits, 623 hc_entry->rmx_updates, 624 hc_entry->rmx_expire); 625 p += len; 626 } 627 THC_UNLOCK(&V_tcp_hostcache.hashbase[i].hch_mtx); 628 } 629#undef msec 630 error = SYSCTL_OUT(req, buf, p - buf); 631 free(buf, M_TEMP); 632 return(error); 633} 634 635/* 636 * Expire and purge (old|all) entries in the tcp_hostcache. Runs 637 * periodically from the callout. 638 */ 639static void 640tcp_hc_purge(void *arg) 641{ 642 CURVNET_SET((struct vnet *) arg); 643 struct hc_metrics *hc_entry, *hc_next; 644 int all = 0; 645 int i; 646 647 if (V_tcp_hostcache.purgeall) { 648 all = 1; 649 V_tcp_hostcache.purgeall = 0; 650 } 651 652 for (i = 0; i < V_tcp_hostcache.hashsize; i++) { 653 THC_LOCK(&V_tcp_hostcache.hashbase[i].hch_mtx); 654 TAILQ_FOREACH_SAFE(hc_entry, 655 &V_tcp_hostcache.hashbase[i].hch_bucket, rmx_q, hc_next) { 656 if (all || hc_entry->rmx_expire <= 0) { 657 TAILQ_REMOVE(&V_tcp_hostcache.hashbase[i].hch_bucket, 658 hc_entry, rmx_q); 659 uma_zfree(V_tcp_hostcache.zone, hc_entry); 660 V_tcp_hostcache.hashbase[i].hch_length--; 661 V_tcp_hostcache.cache_count--; 662 } else 663 hc_entry->rmx_expire -= V_tcp_hostcache.prune; 664 } 665 THC_UNLOCK(&V_tcp_hostcache.hashbase[i].hch_mtx); 666 } 667 668 callout_reset(&V_tcp_hc_callout, V_tcp_hostcache.prune * hz, 669 tcp_hc_purge, arg); 670 CURVNET_RESTORE(); 671} 672