tcp_hostcache.c revision 170405
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 * $FreeBSD: head/sys/netinet/tcp_hostcache.c 170405 2007-06-07 21:41:50Z andre $ 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, bandwidth, max 38 * MTU, 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 has 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 "opt_inet6.h" 68 69#include <sys/param.h> 70#include <sys/systm.h> 71#include <sys/kernel.h> 72#include <sys/lock.h> 73#include <sys/mutex.h> 74#include <sys/malloc.h> 75#include <sys/socket.h> 76#include <sys/socketvar.h> 77#include <sys/sysctl.h> 78 79#include <net/if.h> 80 81#include <netinet/in.h> 82#include <netinet/in_systm.h> 83#include <netinet/ip.h> 84#include <netinet/in_var.h> 85#include <netinet/in_pcb.h> 86#include <netinet/ip_var.h> 87#ifdef INET6 88#include <netinet/ip6.h> 89#include <netinet6/ip6_var.h> 90#endif 91#include <netinet/tcp.h> 92#include <netinet/tcp_var.h> 93#ifdef INET6 94#include <netinet6/tcp6_var.h> 95#endif 96 97#include <vm/uma.h> 98 99 100TAILQ_HEAD(hc_qhead, hc_metrics); 101 102struct hc_head { 103 struct hc_qhead hch_bucket; 104 u_int hch_length; 105 struct mtx hch_mtx; 106}; 107 108struct hc_metrics { 109 /* housekeeping */ 110 TAILQ_ENTRY(hc_metrics) rmx_q; 111 struct hc_head *rmx_head; /* head of bucket tail queue */ 112 struct in_addr ip4; /* IP address */ 113 struct in6_addr ip6; /* IP6 address */ 114 /* endpoint specific values for TCP */ 115 u_long rmx_mtu; /* MTU for this path */ 116 u_long rmx_ssthresh; /* outbound gateway buffer limit */ 117 u_long rmx_rtt; /* estimated round trip time */ 118 u_long rmx_rttvar; /* estimated rtt variance */ 119 u_long rmx_bandwidth; /* estimated bandwidth */ 120 u_long rmx_cwnd; /* congestion window */ 121 u_long rmx_sendpipe; /* outbound delay-bandwidth product */ 122 u_long rmx_recvpipe; /* inbound delay-bandwidth product */ 123 /* TCP hostcache internal data */ 124 int rmx_expire; /* lifetime for object */ 125 u_long rmx_hits; /* number of hits */ 126 u_long rmx_updates; /* number of updates */ 127}; 128 129/* Arbitrary values */ 130#define TCP_HOSTCACHE_HASHSIZE 512 131#define TCP_HOSTCACHE_BUCKETLIMIT 30 132#define TCP_HOSTCACHE_EXPIRE 60*60 /* one hour */ 133#define TCP_HOSTCACHE_PRUNE 5*60 /* every 5 minutes */ 134 135struct tcp_hostcache { 136 struct hc_head *hashbase; 137 uma_zone_t zone; 138 u_int hashsize; 139 u_int hashmask; 140 u_int bucket_limit; 141 u_int cache_count; 142 u_int cache_limit; 143 int expire; 144 int purgeall; 145}; 146static struct tcp_hostcache tcp_hostcache; 147 148static struct callout tcp_hc_callout; 149 150static struct hc_metrics *tcp_hc_lookup(struct in_conninfo *); 151static struct hc_metrics *tcp_hc_insert(struct in_conninfo *); 152static int sysctl_tcp_hc_list(SYSCTL_HANDLER_ARGS); 153static void tcp_hc_purge(void *); 154 155SYSCTL_NODE(_net_inet_tcp, OID_AUTO, hostcache, CTLFLAG_RW, 0, "TCP Host cache"); 156 157SYSCTL_INT(_net_inet_tcp_hostcache, OID_AUTO, cachelimit, CTLFLAG_RDTUN, 158 &tcp_hostcache.cache_limit, 0, "Overall entry limit for hostcache"); 159 160SYSCTL_INT(_net_inet_tcp_hostcache, OID_AUTO, hashsize, CTLFLAG_RDTUN, 161 &tcp_hostcache.hashsize, 0, "Size of TCP hostcache hashtable"); 162 163SYSCTL_INT(_net_inet_tcp_hostcache, OID_AUTO, bucketlimit, CTLFLAG_RDTUN, 164 &tcp_hostcache.bucket_limit, 0, "Per-bucket hash limit for hostcache"); 165 166SYSCTL_INT(_net_inet_tcp_hostcache, OID_AUTO, count, CTLFLAG_RD, 167 &tcp_hostcache.cache_count, 0, "Current number of entries in hostcache"); 168 169SYSCTL_INT(_net_inet_tcp_hostcache, OID_AUTO, expire, CTLFLAG_RW, 170 &tcp_hostcache.expire, 0, "Expire time of TCP hostcache entries"); 171 172SYSCTL_INT(_net_inet_tcp_hostcache, OID_AUTO, purge, CTLFLAG_RW, 173 &tcp_hostcache.purgeall, 0, "Expire all entires on next purge run"); 174 175SYSCTL_PROC(_net_inet_tcp_hostcache, OID_AUTO, list, 176 CTLTYPE_STRING | CTLFLAG_RD | CTLFLAG_SKIP, 0, 0, 177 sysctl_tcp_hc_list, "A", "List of all hostcache entries"); 178 179 180static MALLOC_DEFINE(M_HOSTCACHE, "hostcache", "TCP hostcache"); 181 182#define HOSTCACHE_HASH(ip) \ 183 (((ip)->s_addr ^ ((ip)->s_addr >> 7) ^ ((ip)->s_addr >> 17)) & \ 184 tcp_hostcache.hashmask) 185 186/* XXX: What is the recommended hash to get good entropy for IPv6 addresses? */ 187#define HOSTCACHE_HASH6(ip6) \ 188 (((ip6)->s6_addr32[0] ^ \ 189 (ip6)->s6_addr32[1] ^ \ 190 (ip6)->s6_addr32[2] ^ \ 191 (ip6)->s6_addr32[3]) & \ 192 tcp_hostcache.hashmask) 193 194#define THC_LOCK(lp) mtx_lock(lp) 195#define THC_UNLOCK(lp) mtx_unlock(lp) 196 197void 198tcp_hc_init(void) 199{ 200 int i; 201 202 /* 203 * Initialize hostcache structures. 204 */ 205 tcp_hostcache.cache_count = 0; 206 tcp_hostcache.hashsize = TCP_HOSTCACHE_HASHSIZE; 207 tcp_hostcache.bucket_limit = TCP_HOSTCACHE_BUCKETLIMIT; 208 tcp_hostcache.cache_limit = 209 tcp_hostcache.hashsize * tcp_hostcache.bucket_limit; 210 tcp_hostcache.expire = TCP_HOSTCACHE_EXPIRE; 211 212 TUNABLE_INT_FETCH("net.inet.tcp.hostcache.hashsize", 213 &tcp_hostcache.hashsize); 214 TUNABLE_INT_FETCH("net.inet.tcp.hostcache.cachelimit", 215 &tcp_hostcache.cache_limit); 216 TUNABLE_INT_FETCH("net.inet.tcp.hostcache.bucketlimit", 217 &tcp_hostcache.bucket_limit); 218 if (!powerof2(tcp_hostcache.hashsize)) { 219 printf("WARNING: hostcache hash size is not a power of 2.\n"); 220 tcp_hostcache.hashsize = 512; /* safe default */ 221 } 222 tcp_hostcache.hashmask = tcp_hostcache.hashsize - 1; 223 224 /* 225 * Allocate the hash table. 226 */ 227 tcp_hostcache.hashbase = (struct hc_head *) 228 malloc(tcp_hostcache.hashsize * sizeof(struct hc_head), 229 M_HOSTCACHE, M_WAITOK | M_ZERO); 230 231 /* 232 * Initialize the hash buckets. 233 */ 234 for (i = 0; i < tcp_hostcache.hashsize; i++) { 235 TAILQ_INIT(&tcp_hostcache.hashbase[i].hch_bucket); 236 tcp_hostcache.hashbase[i].hch_length = 0; 237 mtx_init(&tcp_hostcache.hashbase[i].hch_mtx, "tcp_hc_entry", 238 NULL, MTX_DEF); 239 } 240 241 /* 242 * Allocate the hostcache entries. 243 */ 244 tcp_hostcache.zone = uma_zcreate("hostcache", sizeof(struct hc_metrics), 245 NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, 0); 246 uma_zone_set_max(tcp_hostcache.zone, tcp_hostcache.cache_limit); 247 248 /* 249 * Set up periodic cache cleanup. 250 */ 251 callout_init(&tcp_hc_callout, CALLOUT_MPSAFE); 252 callout_reset(&tcp_hc_callout, TCP_HOSTCACHE_PRUNE * hz, tcp_hc_purge, 0); 253} 254 255/* 256 * Internal function: look up an entry in the hostcache or return NULL. 257 * 258 * If an entry has been returned, the caller becomes responsible for 259 * unlocking the bucket row after he is done reading/modifying the entry. 260 */ 261static struct hc_metrics * 262tcp_hc_lookup(struct in_conninfo *inc) 263{ 264 int hash; 265 struct hc_head *hc_head; 266 struct hc_metrics *hc_entry; 267 268 KASSERT(inc != NULL, ("tcp_hc_lookup with NULL in_conninfo pointer")); 269 270 /* 271 * Hash the foreign ip address. 272 */ 273 if (inc->inc_isipv6) 274 hash = HOSTCACHE_HASH6(&inc->inc6_faddr); 275 else 276 hash = HOSTCACHE_HASH(&inc->inc_faddr); 277 278 hc_head = &tcp_hostcache.hashbase[hash]; 279 280 /* 281 * Acquire lock for this bucket row; we release the lock if we don't 282 * find an entry, otherwise the caller has to unlock after he is 283 * done. 284 */ 285 THC_LOCK(&hc_head->hch_mtx); 286 287 /* 288 * Iterate through entries in bucket row looking for a match. 289 */ 290 TAILQ_FOREACH(hc_entry, &hc_head->hch_bucket, rmx_q) { 291 if (inc->inc_isipv6) { 292 if (memcmp(&inc->inc6_faddr, &hc_entry->ip6, 293 sizeof(inc->inc6_faddr)) == 0) 294 return hc_entry; 295 } else { 296 if (memcmp(&inc->inc_faddr, &hc_entry->ip4, 297 sizeof(inc->inc_faddr)) == 0) 298 return hc_entry; 299 } 300 } 301 302 /* 303 * We were unsuccessful and didn't find anything. 304 */ 305 THC_UNLOCK(&hc_head->hch_mtx); 306 return NULL; 307} 308 309/* 310 * Internal function: insert an entry into the hostcache or return NULL if 311 * unable to allocate a new one. 312 * 313 * If an entry has been returned, the caller becomes responsible for 314 * unlocking the bucket row after he is done reading/modifying the entry. 315 */ 316static struct hc_metrics * 317tcp_hc_insert(struct in_conninfo *inc) 318{ 319 int hash; 320 struct hc_head *hc_head; 321 struct hc_metrics *hc_entry; 322 323 KASSERT(inc != NULL, ("tcp_hc_insert with NULL in_conninfo pointer")); 324 325 /* 326 * Hash the foreign ip address. 327 */ 328 if (inc->inc_isipv6) 329 hash = HOSTCACHE_HASH6(&inc->inc6_faddr); 330 else 331 hash = HOSTCACHE_HASH(&inc->inc_faddr); 332 333 hc_head = &tcp_hostcache.hashbase[hash]; 334 335 /* 336 * Acquire lock for this bucket row; we release the lock if we don't 337 * find an entry, otherwise the caller has to unlock after he is 338 * done. 339 */ 340 THC_LOCK(&hc_head->hch_mtx); 341 342 /* 343 * If the bucket limit is reached, reuse the least-used element. 344 */ 345 if (hc_head->hch_length >= tcp_hostcache.bucket_limit || 346 tcp_hostcache.cache_count >= tcp_hostcache.cache_limit) { 347 hc_entry = TAILQ_LAST(&hc_head->hch_bucket, hc_qhead); 348 /* 349 * At first we were dropping the last element, just to 350 * reacquire it in the next two lines again, which isn't very 351 * efficient. Instead just reuse the least used element. 352 * We may drop something that is still "in-use" but we can be 353 * "lossy". 354 * Just give up if this bucket row is empty and we don't have 355 * anything to replace. 356 */ 357 if (hc_entry == NULL) { 358 THC_UNLOCK(&hc_head->hch_mtx); 359 return NULL; 360 } 361 TAILQ_REMOVE(&hc_head->hch_bucket, hc_entry, rmx_q); 362 tcp_hostcache.hashbase[hash].hch_length--; 363 tcp_hostcache.cache_count--; 364 tcpstat.tcps_hc_bucketoverflow++; 365#if 0 366 uma_zfree(tcp_hostcache.zone, hc_entry); 367#endif 368 } else { 369 /* 370 * Allocate a new entry, or balk if not possible. 371 */ 372 hc_entry = uma_zalloc(tcp_hostcache.zone, M_NOWAIT); 373 if (hc_entry == NULL) { 374 THC_UNLOCK(&hc_head->hch_mtx); 375 return NULL; 376 } 377 } 378 379 /* 380 * Initialize basic information of hostcache entry. 381 */ 382 bzero(hc_entry, sizeof(*hc_entry)); 383 if (inc->inc_isipv6) 384 bcopy(&inc->inc6_faddr, &hc_entry->ip6, sizeof(hc_entry->ip6)); 385 else 386 hc_entry->ip4 = inc->inc_faddr; 387 hc_entry->rmx_head = hc_head; 388 hc_entry->rmx_expire = tcp_hostcache.expire; 389 390 /* 391 * Put it upfront. 392 */ 393 TAILQ_INSERT_HEAD(&hc_head->hch_bucket, hc_entry, rmx_q); 394 tcp_hostcache.hashbase[hash].hch_length++; 395 tcp_hostcache.cache_count++; 396 tcpstat.tcps_hc_added++; 397 398 return hc_entry; 399} 400 401/* 402 * External function: look up an entry in the hostcache and fill out the 403 * supplied TCP metrics structure. Fills in NULL when no entry was found or 404 * a value is not set. 405 */ 406void 407tcp_hc_get(struct in_conninfo *inc, struct hc_metrics_lite *hc_metrics_lite) 408{ 409 struct hc_metrics *hc_entry; 410 411 /* 412 * Find the right bucket. 413 */ 414 hc_entry = tcp_hc_lookup(inc); 415 416 /* 417 * If we don't have an existing object. 418 */ 419 if (hc_entry == NULL) { 420 bzero(hc_metrics_lite, sizeof(*hc_metrics_lite)); 421 return; 422 } 423 hc_entry->rmx_hits++; 424 hc_entry->rmx_expire = tcp_hostcache.expire; /* start over again */ 425 426 hc_metrics_lite->rmx_mtu = hc_entry->rmx_mtu; 427 hc_metrics_lite->rmx_ssthresh = hc_entry->rmx_ssthresh; 428 hc_metrics_lite->rmx_rtt = hc_entry->rmx_rtt; 429 hc_metrics_lite->rmx_rttvar = hc_entry->rmx_rttvar; 430 hc_metrics_lite->rmx_bandwidth = hc_entry->rmx_bandwidth; 431 hc_metrics_lite->rmx_cwnd = hc_entry->rmx_cwnd; 432 hc_metrics_lite->rmx_sendpipe = hc_entry->rmx_sendpipe; 433 hc_metrics_lite->rmx_recvpipe = hc_entry->rmx_recvpipe; 434 435 /* 436 * Unlock bucket row. 437 */ 438 THC_UNLOCK(&hc_entry->rmx_head->hch_mtx); 439} 440 441/* 442 * External function: look up an entry in the hostcache and return the 443 * discovered path MTU. Returns NULL if no entry is found or value is not 444 * set. 445 */ 446u_long 447tcp_hc_getmtu(struct in_conninfo *inc) 448{ 449 struct hc_metrics *hc_entry; 450 u_long mtu; 451 452 hc_entry = tcp_hc_lookup(inc); 453 if (hc_entry == NULL) { 454 return 0; 455 } 456 hc_entry->rmx_hits++; 457 hc_entry->rmx_expire = tcp_hostcache.expire; /* start over again */ 458 459 mtu = hc_entry->rmx_mtu; 460 THC_UNLOCK(&hc_entry->rmx_head->hch_mtx); 461 return mtu; 462} 463 464/* 465 * External function: update the MTU value of an entry in the hostcache. 466 * Creates a new entry if none was found. 467 */ 468void 469tcp_hc_updatemtu(struct in_conninfo *inc, u_long mtu) 470{ 471 struct hc_metrics *hc_entry; 472 473 /* 474 * Find the right bucket. 475 */ 476 hc_entry = tcp_hc_lookup(inc); 477 478 /* 479 * If we don't have an existing object, try to insert a new one. 480 */ 481 if (hc_entry == NULL) { 482 hc_entry = tcp_hc_insert(inc); 483 if (hc_entry == NULL) 484 return; 485 } 486 hc_entry->rmx_updates++; 487 hc_entry->rmx_expire = tcp_hostcache.expire; /* start over again */ 488 489 hc_entry->rmx_mtu = mtu; 490 491 /* 492 * Put it upfront so we find it faster next time. 493 */ 494 TAILQ_REMOVE(&hc_entry->rmx_head->hch_bucket, hc_entry, rmx_q); 495 TAILQ_INSERT_HEAD(&hc_entry->rmx_head->hch_bucket, hc_entry, rmx_q); 496 497 /* 498 * Unlock bucket row. 499 */ 500 THC_UNLOCK(&hc_entry->rmx_head->hch_mtx); 501} 502 503/* 504 * External function: update the TCP metrics of an entry in the hostcache. 505 * Creates a new entry if none was found. 506 */ 507void 508tcp_hc_update(struct in_conninfo *inc, struct hc_metrics_lite *hcml) 509{ 510 struct hc_metrics *hc_entry; 511 512 hc_entry = tcp_hc_lookup(inc); 513 if (hc_entry == NULL) { 514 hc_entry = tcp_hc_insert(inc); 515 if (hc_entry == NULL) 516 return; 517 } 518 hc_entry->rmx_updates++; 519 hc_entry->rmx_expire = tcp_hostcache.expire; /* start over again */ 520 521 if (hcml->rmx_rtt != 0) { 522 if (hc_entry->rmx_rtt == 0) 523 hc_entry->rmx_rtt = hcml->rmx_rtt; 524 else 525 hc_entry->rmx_rtt = 526 (hc_entry->rmx_rtt + hcml->rmx_rtt) / 2; 527 tcpstat.tcps_cachedrtt++; 528 } 529 if (hcml->rmx_rttvar != 0) { 530 if (hc_entry->rmx_rttvar == 0) 531 hc_entry->rmx_rttvar = hcml->rmx_rttvar; 532 else 533 hc_entry->rmx_rttvar = 534 (hc_entry->rmx_rttvar + hcml->rmx_rttvar) / 2; 535 tcpstat.tcps_cachedrttvar++; 536 } 537 if (hcml->rmx_ssthresh != 0) { 538 if (hc_entry->rmx_ssthresh == 0) 539 hc_entry->rmx_ssthresh = hcml->rmx_ssthresh; 540 else 541 hc_entry->rmx_ssthresh = 542 (hc_entry->rmx_ssthresh + hcml->rmx_ssthresh) / 2; 543 tcpstat.tcps_cachedssthresh++; 544 } 545 if (hcml->rmx_bandwidth != 0) { 546 if (hc_entry->rmx_bandwidth == 0) 547 hc_entry->rmx_bandwidth = hcml->rmx_bandwidth; 548 else 549 hc_entry->rmx_bandwidth = 550 (hc_entry->rmx_bandwidth + hcml->rmx_bandwidth) / 2; 551 /* tcpstat.tcps_cachedbandwidth++; */ 552 } 553 if (hcml->rmx_cwnd != 0) { 554 if (hc_entry->rmx_cwnd == 0) 555 hc_entry->rmx_cwnd = hcml->rmx_cwnd; 556 else 557 hc_entry->rmx_cwnd = 558 (hc_entry->rmx_cwnd + hcml->rmx_cwnd) / 2; 559 /* tcpstat.tcps_cachedcwnd++; */ 560 } 561 if (hcml->rmx_sendpipe != 0) { 562 if (hc_entry->rmx_sendpipe == 0) 563 hc_entry->rmx_sendpipe = hcml->rmx_sendpipe; 564 else 565 hc_entry->rmx_sendpipe = 566 (hc_entry->rmx_sendpipe + hcml->rmx_sendpipe) /2; 567 /* tcpstat.tcps_cachedsendpipe++; */ 568 } 569 if (hcml->rmx_recvpipe != 0) { 570 if (hc_entry->rmx_recvpipe == 0) 571 hc_entry->rmx_recvpipe = hcml->rmx_recvpipe; 572 else 573 hc_entry->rmx_recvpipe = 574 (hc_entry->rmx_recvpipe + hcml->rmx_recvpipe) /2; 575 /* tcpstat.tcps_cachedrecvpipe++; */ 576 } 577 578 TAILQ_REMOVE(&hc_entry->rmx_head->hch_bucket, hc_entry, rmx_q); 579 TAILQ_INSERT_HEAD(&hc_entry->rmx_head->hch_bucket, hc_entry, rmx_q); 580 THC_UNLOCK(&hc_entry->rmx_head->hch_mtx); 581} 582 583/* 584 * Sysctl function: prints the list and values of all hostcache entries in 585 * unsorted order. 586 */ 587static int 588sysctl_tcp_hc_list(SYSCTL_HANDLER_ARGS) 589{ 590 int bufsize; 591 int linesize = 128; 592 char *p, *buf; 593 int len, i, error; 594 struct hc_metrics *hc_entry; 595#ifdef INET6 596 char ip6buf[INET6_ADDRSTRLEN]; 597#endif 598 599 bufsize = linesize * (tcp_hostcache.cache_count + 1); 600 601 p = buf = (char *)malloc(bufsize, M_TEMP, M_WAITOK|M_ZERO); 602 603 len = snprintf(p, linesize, 604 "\nIP address MTU SSTRESH RTT RTTVAR BANDWIDTH " 605 " CWND SENDPIPE RECVPIPE HITS UPD EXP\n"); 606 p += len; 607 608#define msec(u) (((u) + 500) / 1000) 609 for (i = 0; i < tcp_hostcache.hashsize; i++) { 610 THC_LOCK(&tcp_hostcache.hashbase[i].hch_mtx); 611 TAILQ_FOREACH(hc_entry, &tcp_hostcache.hashbase[i].hch_bucket, 612 rmx_q) { 613 len = snprintf(p, linesize, 614 "%-15s %5lu %8lu %6lums %6lums %9lu %8lu %8lu %8lu " 615 "%4lu %4lu %4i\n", 616 hc_entry->ip4.s_addr ? inet_ntoa(hc_entry->ip4) : 617#ifdef INET6 618 ip6_sprintf(ip6buf, &hc_entry->ip6), 619#else 620 "IPv6?", 621#endif 622 hc_entry->rmx_mtu, 623 hc_entry->rmx_ssthresh, 624 msec(hc_entry->rmx_rtt * 625 (RTM_RTTUNIT / (hz * TCP_RTT_SCALE))), 626 msec(hc_entry->rmx_rttvar * 627 (RTM_RTTUNIT / (hz * TCP_RTT_SCALE))), 628 hc_entry->rmx_bandwidth * 8, 629 hc_entry->rmx_cwnd, 630 hc_entry->rmx_sendpipe, 631 hc_entry->rmx_recvpipe, 632 hc_entry->rmx_hits, 633 hc_entry->rmx_updates, 634 hc_entry->rmx_expire); 635 p += len; 636 } 637 THC_UNLOCK(&tcp_hostcache.hashbase[i].hch_mtx); 638 } 639#undef msec 640 error = SYSCTL_OUT(req, buf, p - buf); 641 free(buf, M_TEMP); 642 return(error); 643} 644 645/* 646 * Expire and purge (old|all) entries in the tcp_hostcache. Runs 647 * periodically from the callout. 648 */ 649static void 650tcp_hc_purge(void *arg) 651{ 652 struct hc_metrics *hc_entry, *hc_next; 653 int all = (intptr_t)arg; 654 int i; 655 656 if (tcp_hostcache.purgeall) { 657 all = 1; 658 tcp_hostcache.purgeall = 0; 659 } 660 661 for (i = 0; i < tcp_hostcache.hashsize; i++) { 662 THC_LOCK(&tcp_hostcache.hashbase[i].hch_mtx); 663 TAILQ_FOREACH_SAFE(hc_entry, &tcp_hostcache.hashbase[i].hch_bucket, 664 rmx_q, hc_next) { 665 if (all || hc_entry->rmx_expire <= 0) { 666 TAILQ_REMOVE(&tcp_hostcache.hashbase[i].hch_bucket, 667 hc_entry, rmx_q); 668 uma_zfree(tcp_hostcache.zone, hc_entry); 669 tcp_hostcache.hashbase[i].hch_length--; 670 tcp_hostcache.cache_count--; 671 } else 672 hc_entry->rmx_expire -= TCP_HOSTCACHE_PRUNE; 673 } 674 THC_UNLOCK(&tcp_hostcache.hashbase[i].hch_mtx); 675 } 676 callout_reset(&tcp_hc_callout, TCP_HOSTCACHE_PRUNE * hz, tcp_hc_purge, 0); 677} 678