1 /*- 2 * SPDX-License-Identifier: BSD-3-Clause 3 * 4 * Copyright (c) 2002 Andre Oppermann, Internet Business Solutions AG 5 * All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 3. The name of the author may not be used to endorse or promote 16 * products derived from this software without specific prior written 17 * permission. 18 * 19 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 22 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 29 * SUCH DAMAGE. 30 */ 31 32 /* 33 * The tcp_hostcache moves the tcp-specific cached metrics from the routing 34 * table to a dedicated structure indexed by the remote IP address. It keeps 35 * information on the measured TCP parameters of past TCP sessions to allow 36 * better initial start values to be used with later connections to/from the 37 * same source. Depending on the network parameters (delay, max MTU, 38 * congestion window) between local and remote sites, this can lead to 39 * significant speed-ups for new TCP connections after the first one. 40 * 41 * Due to the tcp_hostcache, all TCP-specific metrics information in the 42 * routing table have been removed. The inpcb no longer keeps a pointer to 43 * the routing entry, and protocol-initiated route cloning has been removed 44 * as well. With these changes, the routing table has gone back to being 45 * more lightwight and only carries information related to packet forwarding. 46 * 47 * tcp_hostcache is designed for multiple concurrent access in SMP 48 * environments and high contention. All bucket rows have their own lock and 49 * thus multiple lookups and modifies can be done at the same time as long as 50 * they are in different bucket rows. If a request for insertion of a new 51 * record can't be satisfied, it simply returns an empty structure. Nobody 52 * and nothing outside of tcp_hostcache.c will ever point directly to any 53 * entry in the tcp_hostcache. All communication is done in an 54 * object-oriented way and only functions of tcp_hostcache will manipulate 55 * hostcache entries. Otherwise, we are unable to achieve good behaviour in 56 * concurrent access situations. Since tcp_hostcache is only caching 57 * information, there are no fatal consequences if we either can't satisfy 58 * any particular request or have to drop/overwrite an existing entry because 59 * of bucket limit memory constrains. 60 */ 61 62 /* 63 * Many thanks to jlemon for basic structure of tcp_syncache which is being 64 * followed here. 65 */ 66 67 #include <sys/cdefs.h> 68 __FBSDID("$FreeBSD$"); 69 70 #include "opt_inet6.h" 71 72 #include <sys/param.h> 73 #include <sys/systm.h> 74 #include <sys/hash.h> 75 #include <sys/jail.h> 76 #include <sys/kernel.h> 77 #include <sys/lock.h> 78 #include <sys/mutex.h> 79 #include <sys/malloc.h> 80 #include <sys/proc.h> 81 #include <sys/sbuf.h> 82 #include <sys/socket.h> 83 #include <sys/socketvar.h> 84 #include <sys/sysctl.h> 85 86 #include <net/vnet.h> 87 88 #include <netinet/in.h> 89 #include <netinet/in_pcb.h> 90 #include <netinet/tcp.h> 91 #include <netinet/tcp_var.h> 92 93 #include <vm/uma.h> 94 95 TAILQ_HEAD(hc_qhead, hc_metrics); 96 97 struct hc_head { 98 struct hc_qhead hch_bucket; 99 u_int hch_length; 100 struct mtx hch_mtx; 101 }; 102 103 struct hc_metrics { 104 /* housekeeping */ 105 TAILQ_ENTRY(hc_metrics) rmx_q; 106 struct hc_head *rmx_head; /* head of bucket tail queue */ 107 struct in_addr ip4; /* IP address */ 108 struct in6_addr ip6; /* IP6 address */ 109 uint32_t ip6_zoneid; /* IPv6 scope zone id */ 110 /* endpoint specific values for tcp */ 111 uint32_t rmx_mtu; /* MTU for this path */ 112 uint32_t rmx_ssthresh; /* outbound gateway buffer limit */ 113 uint32_t rmx_rtt; /* estimated round trip time */ 114 uint32_t rmx_rttvar; /* estimated rtt variance */ 115 uint32_t rmx_cwnd; /* congestion window */ 116 uint32_t rmx_sendpipe; /* outbound delay-bandwidth product */ 117 uint32_t rmx_recvpipe; /* inbound delay-bandwidth product */ 118 /* TCP hostcache internal data */ 119 int rmx_expire; /* lifetime for object */ 120 #ifdef TCP_HC_COUNTERS 121 u_long rmx_hits; /* number of hits */ 122 u_long rmx_updates; /* number of updates */ 123 #endif 124 }; 125 126 struct tcp_hostcache { 127 struct hc_head *hashbase; 128 uma_zone_t zone; 129 u_int hashsize; 130 u_int hashmask; 131 u_int hashsalt; 132 u_int bucket_limit; 133 u_int cache_count; 134 u_int cache_limit; 135 int expire; 136 int prune; 137 int purgeall; 138 }; 139 140 /* Arbitrary values */ 141 #define TCP_HOSTCACHE_HASHSIZE 512 142 #define TCP_HOSTCACHE_BUCKETLIMIT 30 143 #define TCP_HOSTCACHE_EXPIRE 60*60 /* one hour */ 144 #define TCP_HOSTCACHE_PRUNE 5*60 /* every 5 minutes */ 145 146 VNET_DEFINE_STATIC(struct tcp_hostcache, tcp_hostcache); 147 #define V_tcp_hostcache VNET(tcp_hostcache) 148 149 VNET_DEFINE_STATIC(struct callout, tcp_hc_callout); 150 #define V_tcp_hc_callout VNET(tcp_hc_callout) 151 152 static struct hc_metrics *tcp_hc_lookup(struct in_conninfo *, bool); 153 static struct hc_metrics *tcp_hc_insert(struct in_conninfo *); 154 static int sysctl_tcp_hc_list(SYSCTL_HANDLER_ARGS); 155 static int sysctl_tcp_hc_histo(SYSCTL_HANDLER_ARGS); 156 static int sysctl_tcp_hc_purgenow(SYSCTL_HANDLER_ARGS); 157 static void tcp_hc_purge_internal(int); 158 static void tcp_hc_purge(void *); 159 160 static SYSCTL_NODE(_net_inet_tcp, OID_AUTO, hostcache, 161 CTLFLAG_RW | CTLFLAG_MPSAFE, 0, 162 "TCP Host cache"); 163 164 VNET_DEFINE(int, tcp_use_hostcache) = 1; 165 #define V_tcp_use_hostcache VNET(tcp_use_hostcache) 166 SYSCTL_INT(_net_inet_tcp_hostcache, OID_AUTO, enable, CTLFLAG_VNET | CTLFLAG_RW, 167 &VNET_NAME(tcp_use_hostcache), 0, 168 "Enable the TCP hostcache"); 169 170 SYSCTL_UINT(_net_inet_tcp_hostcache, OID_AUTO, cachelimit, CTLFLAG_VNET | CTLFLAG_RDTUN, 171 &VNET_NAME(tcp_hostcache.cache_limit), 0, 172 "Overall entry limit for hostcache"); 173 174 SYSCTL_UINT(_net_inet_tcp_hostcache, OID_AUTO, hashsize, CTLFLAG_VNET | CTLFLAG_RDTUN, 175 &VNET_NAME(tcp_hostcache.hashsize), 0, 176 "Size of TCP hostcache hashtable"); 177 178 SYSCTL_UINT(_net_inet_tcp_hostcache, OID_AUTO, bucketlimit, 179 CTLFLAG_VNET | CTLFLAG_RDTUN, &VNET_NAME(tcp_hostcache.bucket_limit), 0, 180 "Per-bucket hash limit for hostcache"); 181 182 SYSCTL_UINT(_net_inet_tcp_hostcache, OID_AUTO, count, CTLFLAG_VNET | CTLFLAG_RD, 183 &VNET_NAME(tcp_hostcache.cache_count), 0, 184 "Current number of entries in hostcache"); 185 186 SYSCTL_INT(_net_inet_tcp_hostcache, OID_AUTO, expire, CTLFLAG_VNET | CTLFLAG_RW, 187 &VNET_NAME(tcp_hostcache.expire), 0, 188 "Expire time of TCP hostcache entries"); 189 190 SYSCTL_INT(_net_inet_tcp_hostcache, OID_AUTO, prune, CTLFLAG_VNET | CTLFLAG_RW, 191 &VNET_NAME(tcp_hostcache.prune), 0, 192 "Time between purge runs"); 193 194 SYSCTL_INT(_net_inet_tcp_hostcache, OID_AUTO, purge, CTLFLAG_VNET | CTLFLAG_RW, 195 &VNET_NAME(tcp_hostcache.purgeall), 0, 196 "Expire all entires on next purge run"); 197 198 SYSCTL_PROC(_net_inet_tcp_hostcache, OID_AUTO, list, 199 CTLTYPE_STRING | CTLFLAG_RD | CTLFLAG_SKIP | CTLFLAG_MPSAFE, 200 0, 0, sysctl_tcp_hc_list, "A", 201 "List of all hostcache entries"); 202 203 SYSCTL_PROC(_net_inet_tcp_hostcache, OID_AUTO, histo, 204 CTLTYPE_STRING | CTLFLAG_RD | CTLFLAG_SKIP | CTLFLAG_MPSAFE, 205 0, 0, sysctl_tcp_hc_histo, "A", 206 "Print a histogram of hostcache hashbucket utilization"); 207 208 SYSCTL_PROC(_net_inet_tcp_hostcache, OID_AUTO, purgenow, 209 CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_MPSAFE, 210 NULL, 0, sysctl_tcp_hc_purgenow, "I", 211 "Immediately purge all entries"); 212 213 static MALLOC_DEFINE(M_HOSTCACHE, "hostcache", "TCP hostcache"); 214 215 /* Use jenkins_hash32(), as in other parts of the tcp stack */ 216 #define HOSTCACHE_HASH(ip) \ 217 (jenkins_hash32((uint32_t *)(ip), 1, V_tcp_hostcache.hashsalt) & \ 218 V_tcp_hostcache.hashmask) 219 220 #define HOSTCACHE_HASH6(ip6) \ 221 (jenkins_hash32((uint32_t *)&((ip6)->s6_addr32[0]), 4, \ 222 V_tcp_hostcache.hashsalt) & \ 223 V_tcp_hostcache.hashmask) 224 225 #define THC_LOCK(lp) mtx_lock(lp) 226 #define THC_UNLOCK(lp) mtx_unlock(lp) 227 228 void 229 tcp_hc_init(void) 230 { 231 u_int cache_limit; 232 int i; 233 234 /* 235 * Initialize hostcache structures. 236 */ 237 atomic_store_int(&V_tcp_hostcache.cache_count, 0); 238 V_tcp_hostcache.hashsize = TCP_HOSTCACHE_HASHSIZE; 239 V_tcp_hostcache.bucket_limit = TCP_HOSTCACHE_BUCKETLIMIT; 240 V_tcp_hostcache.expire = TCP_HOSTCACHE_EXPIRE; 241 V_tcp_hostcache.prune = TCP_HOSTCACHE_PRUNE; 242 V_tcp_hostcache.hashsalt = arc4random(); 243 244 TUNABLE_INT_FETCH("net.inet.tcp.hostcache.hashsize", 245 &V_tcp_hostcache.hashsize); 246 if (!powerof2(V_tcp_hostcache.hashsize)) { 247 printf("WARNING: hostcache hash size is not a power of 2.\n"); 248 V_tcp_hostcache.hashsize = TCP_HOSTCACHE_HASHSIZE; /* default */ 249 } 250 V_tcp_hostcache.hashmask = V_tcp_hostcache.hashsize - 1; 251 252 TUNABLE_INT_FETCH("net.inet.tcp.hostcache.bucketlimit", 253 &V_tcp_hostcache.bucket_limit); 254 255 cache_limit = V_tcp_hostcache.hashsize * V_tcp_hostcache.bucket_limit; 256 V_tcp_hostcache.cache_limit = cache_limit; 257 TUNABLE_INT_FETCH("net.inet.tcp.hostcache.cachelimit", 258 &V_tcp_hostcache.cache_limit); 259 if (V_tcp_hostcache.cache_limit > cache_limit) 260 V_tcp_hostcache.cache_limit = cache_limit; 261 262 /* 263 * Allocate the hash table. 264 */ 265 V_tcp_hostcache.hashbase = (struct hc_head *) 266 malloc(V_tcp_hostcache.hashsize * sizeof(struct hc_head), 267 M_HOSTCACHE, M_WAITOK | M_ZERO); 268 269 /* 270 * Initialize the hash buckets. 271 */ 272 for (i = 0; i < V_tcp_hostcache.hashsize; i++) { 273 TAILQ_INIT(&V_tcp_hostcache.hashbase[i].hch_bucket); 274 V_tcp_hostcache.hashbase[i].hch_length = 0; 275 mtx_init(&V_tcp_hostcache.hashbase[i].hch_mtx, "tcp_hc_entry", 276 NULL, MTX_DEF); 277 } 278 279 /* 280 * Allocate the hostcache entries. 281 */ 282 V_tcp_hostcache.zone = 283 uma_zcreate("hostcache", sizeof(struct hc_metrics), 284 NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, 0); 285 uma_zone_set_max(V_tcp_hostcache.zone, V_tcp_hostcache.cache_limit); 286 287 /* 288 * Set up periodic cache cleanup. 289 */ 290 callout_init(&V_tcp_hc_callout, 1); 291 callout_reset(&V_tcp_hc_callout, V_tcp_hostcache.prune * hz, 292 tcp_hc_purge, curvnet); 293 } 294 295 #ifdef VIMAGE 296 void 297 tcp_hc_destroy(void) 298 { 299 int i; 300 301 callout_drain(&V_tcp_hc_callout); 302 303 /* Purge all hc entries. */ 304 tcp_hc_purge_internal(1); 305 306 /* Free the uma zone and the allocated hash table. */ 307 uma_zdestroy(V_tcp_hostcache.zone); 308 309 for (i = 0; i < V_tcp_hostcache.hashsize; i++) 310 mtx_destroy(&V_tcp_hostcache.hashbase[i].hch_mtx); 311 free(V_tcp_hostcache.hashbase, M_HOSTCACHE); 312 } 313 #endif 314 315 /* 316 * Internal function: look up an entry in the hostcache or return NULL. 317 * 318 * If an entry has been returned, the caller becomes responsible for 319 * unlocking the bucket row after he is done reading/modifying the entry. 320 */ 321 static struct hc_metrics * 322 tcp_hc_lookup(struct in_conninfo *inc, bool update) 323 { 324 int hash; 325 struct hc_head *hc_head; 326 struct hc_metrics *hc_entry; 327 328 if (!V_tcp_use_hostcache) 329 return NULL; 330 331 KASSERT(inc != NULL, ("tcp_hc_lookup with NULL in_conninfo pointer")); 332 333 /* 334 * Hash the foreign ip address. 335 */ 336 if (inc->inc_flags & INC_ISIPV6) 337 hash = HOSTCACHE_HASH6(&inc->inc6_faddr); 338 else 339 hash = HOSTCACHE_HASH(&inc->inc_faddr); 340 341 hc_head = &V_tcp_hostcache.hashbase[hash]; 342 343 /* 344 * Acquire lock for this bucket row; we release the lock if we don't 345 * find an entry, otherwise the caller has to unlock after he is 346 * done. 347 */ 348 THC_LOCK(&hc_head->hch_mtx); 349 350 /* 351 * Iterate through entries in bucket row looking for a match. 352 */ 353 TAILQ_FOREACH(hc_entry, &hc_head->hch_bucket, rmx_q) { 354 if (inc->inc_flags & INC_ISIPV6) { 355 /* XXX: check ip6_zoneid */ 356 if (memcmp(&inc->inc6_faddr, &hc_entry->ip6, 357 sizeof(inc->inc6_faddr)) == 0) 358 goto found; 359 } else { 360 if (memcmp(&inc->inc_faddr, &hc_entry->ip4, 361 sizeof(inc->inc_faddr)) == 0) 362 goto found; 363 } 364 } 365 366 /* 367 * We were unsuccessful and didn't find anything. 368 */ 369 THC_UNLOCK(&hc_head->hch_mtx); 370 return (NULL); 371 372 found: 373 #ifdef TCP_HC_COUNTERS 374 if (update) 375 hc_entry->rmx_updates++; 376 else 377 hc_entry->rmx_hits++; 378 #endif 379 hc_entry->rmx_expire = V_tcp_hostcache.expire; 380 381 return (hc_entry); 382 } 383 384 /* 385 * Internal function: insert an entry into the hostcache or return NULL if 386 * unable to allocate a new one. 387 * 388 * If an entry has been returned, the caller becomes responsible for 389 * unlocking the bucket row after he is done reading/modifying the entry. 390 */ 391 static struct hc_metrics * 392 tcp_hc_insert(struct in_conninfo *inc) 393 { 394 int hash; 395 struct hc_head *hc_head; 396 struct hc_metrics *hc_entry; 397 398 if (!V_tcp_use_hostcache) 399 return NULL; 400 401 KASSERT(inc != NULL, ("tcp_hc_insert with NULL in_conninfo pointer")); 402 403 /* 404 * Hash the foreign ip address. 405 */ 406 if (inc->inc_flags & INC_ISIPV6) 407 hash = HOSTCACHE_HASH6(&inc->inc6_faddr); 408 else 409 hash = HOSTCACHE_HASH(&inc->inc_faddr); 410 411 hc_head = &V_tcp_hostcache.hashbase[hash]; 412 413 /* 414 * Acquire lock for this bucket row; we release the lock if we don't 415 * find an entry, otherwise the caller has to unlock after he is 416 * done. 417 */ 418 THC_LOCK(&hc_head->hch_mtx); 419 420 /* 421 * If the bucket limit is reached, reuse the least-used element. 422 */ 423 if (hc_head->hch_length >= V_tcp_hostcache.bucket_limit || 424 atomic_load_int(&V_tcp_hostcache.cache_count) >= V_tcp_hostcache.cache_limit) { 425 hc_entry = TAILQ_LAST(&hc_head->hch_bucket, hc_qhead); 426 /* 427 * At first we were dropping the last element, just to 428 * reacquire it in the next two lines again, which isn't very 429 * efficient. Instead just reuse the least used element. 430 * We may drop something that is still "in-use" but we can be 431 * "lossy". 432 * Just give up if this bucket row is empty and we don't have 433 * anything to replace. 434 */ 435 if (hc_entry == NULL) { 436 THC_UNLOCK(&hc_head->hch_mtx); 437 return NULL; 438 } 439 TAILQ_REMOVE(&hc_head->hch_bucket, hc_entry, rmx_q); 440 KASSERT(V_tcp_hostcache.hashbase[hash].hch_length > 0 && 441 V_tcp_hostcache.hashbase[hash].hch_length <= 442 V_tcp_hostcache.bucket_limit, 443 ("tcp_hostcache: bucket length range violated at %u: %u", 444 hash, V_tcp_hostcache.hashbase[hash].hch_length)); 445 V_tcp_hostcache.hashbase[hash].hch_length--; 446 atomic_subtract_int(&V_tcp_hostcache.cache_count, 1); 447 TCPSTAT_INC(tcps_hc_bucketoverflow); 448 #if 0 449 uma_zfree(V_tcp_hostcache.zone, hc_entry); 450 #endif 451 } else { 452 /* 453 * Allocate a new entry, or balk if not possible. 454 */ 455 hc_entry = uma_zalloc(V_tcp_hostcache.zone, M_NOWAIT); 456 if (hc_entry == NULL) { 457 THC_UNLOCK(&hc_head->hch_mtx); 458 return NULL; 459 } 460 } 461 462 /* 463 * Initialize basic information of hostcache entry. 464 */ 465 bzero(hc_entry, sizeof(*hc_entry)); 466 if (inc->inc_flags & INC_ISIPV6) { 467 hc_entry->ip6 = inc->inc6_faddr; 468 hc_entry->ip6_zoneid = inc->inc6_zoneid; 469 } else 470 hc_entry->ip4 = inc->inc_faddr; 471 hc_entry->rmx_head = hc_head; 472 hc_entry->rmx_expire = V_tcp_hostcache.expire; 473 474 /* 475 * Put it upfront. 476 */ 477 TAILQ_INSERT_HEAD(&hc_head->hch_bucket, hc_entry, rmx_q); 478 V_tcp_hostcache.hashbase[hash].hch_length++; 479 KASSERT(V_tcp_hostcache.hashbase[hash].hch_length < 480 V_tcp_hostcache.bucket_limit, 481 ("tcp_hostcache: bucket length too high at %u: %u", 482 hash, V_tcp_hostcache.hashbase[hash].hch_length)); 483 atomic_add_int(&V_tcp_hostcache.cache_count, 1); 484 TCPSTAT_INC(tcps_hc_added); 485 486 return hc_entry; 487 } 488 489 /* 490 * External function: look up an entry in the hostcache and fill out the 491 * supplied TCP metrics structure. Fills in NULL when no entry was found or 492 * a value is not set. 493 */ 494 void 495 tcp_hc_get(struct in_conninfo *inc, struct hc_metrics_lite *hc_metrics_lite) 496 { 497 struct hc_metrics *hc_entry; 498 499 if (!V_tcp_use_hostcache) { 500 bzero(hc_metrics_lite, sizeof(*hc_metrics_lite)); 501 return; 502 } 503 504 /* 505 * Find the right bucket. 506 */ 507 hc_entry = tcp_hc_lookup(inc, false); 508 509 /* 510 * If we don't have an existing object. 511 */ 512 if (hc_entry == NULL) { 513 bzero(hc_metrics_lite, sizeof(*hc_metrics_lite)); 514 return; 515 } 516 517 hc_metrics_lite->rmx_mtu = hc_entry->rmx_mtu; 518 hc_metrics_lite->rmx_ssthresh = hc_entry->rmx_ssthresh; 519 hc_metrics_lite->rmx_rtt = hc_entry->rmx_rtt; 520 hc_metrics_lite->rmx_rttvar = hc_entry->rmx_rttvar; 521 hc_metrics_lite->rmx_cwnd = hc_entry->rmx_cwnd; 522 hc_metrics_lite->rmx_sendpipe = hc_entry->rmx_sendpipe; 523 hc_metrics_lite->rmx_recvpipe = hc_entry->rmx_recvpipe; 524 525 /* 526 * Unlock bucket row. 527 */ 528 THC_UNLOCK(&hc_entry->rmx_head->hch_mtx); 529 } 530 531 /* 532 * External function: look up an entry in the hostcache and return the 533 * discovered path MTU. Returns 0 if no entry is found or value is not 534 * set. 535 */ 536 uint32_t 537 tcp_hc_getmtu(struct in_conninfo *inc) 538 { 539 struct hc_metrics *hc_entry; 540 uint32_t mtu; 541 542 if (!V_tcp_use_hostcache) 543 return 0; 544 545 hc_entry = tcp_hc_lookup(inc, false); 546 if (hc_entry == NULL) { 547 return 0; 548 } 549 550 mtu = hc_entry->rmx_mtu; 551 THC_UNLOCK(&hc_entry->rmx_head->hch_mtx); 552 return mtu; 553 } 554 555 /* 556 * External function: update the MTU value of an entry in the hostcache. 557 * Creates a new entry if none was found. 558 */ 559 void 560 tcp_hc_updatemtu(struct in_conninfo *inc, uint32_t mtu) 561 { 562 struct hc_metrics *hc_entry; 563 564 if (!V_tcp_use_hostcache) 565 return; 566 567 /* 568 * Find the right bucket. 569 */ 570 hc_entry = tcp_hc_lookup(inc, true); 571 572 /* 573 * If we don't have an existing object, try to insert a new one. 574 */ 575 if (hc_entry == NULL) { 576 hc_entry = tcp_hc_insert(inc); 577 if (hc_entry == NULL) 578 return; 579 } 580 581 hc_entry->rmx_mtu = mtu; 582 583 /* 584 * Put it upfront so we find it faster next time. 585 */ 586 TAILQ_REMOVE(&hc_entry->rmx_head->hch_bucket, hc_entry, rmx_q); 587 TAILQ_INSERT_HEAD(&hc_entry->rmx_head->hch_bucket, hc_entry, rmx_q); 588 589 /* 590 * Unlock bucket row. 591 */ 592 THC_UNLOCK(&hc_entry->rmx_head->hch_mtx); 593 } 594 595 /* 596 * External function: update the TCP metrics of an entry in the hostcache. 597 * Creates a new entry if none was found. 598 */ 599 void 600 tcp_hc_update(struct in_conninfo *inc, struct hc_metrics_lite *hcml) 601 { 602 struct hc_metrics *hc_entry; 603 604 if (!V_tcp_use_hostcache) 605 return; 606 607 hc_entry = tcp_hc_lookup(inc, true); 608 if (hc_entry == NULL) { 609 hc_entry = tcp_hc_insert(inc); 610 if (hc_entry == NULL) 611 return; 612 } 613 614 if (hcml->rmx_rtt != 0) { 615 if (hc_entry->rmx_rtt == 0) 616 hc_entry->rmx_rtt = hcml->rmx_rtt; 617 else 618 hc_entry->rmx_rtt = ((uint64_t)hc_entry->rmx_rtt + 619 (uint64_t)hcml->rmx_rtt) / 2; 620 TCPSTAT_INC(tcps_cachedrtt); 621 } 622 if (hcml->rmx_rttvar != 0) { 623 if (hc_entry->rmx_rttvar == 0) 624 hc_entry->rmx_rttvar = hcml->rmx_rttvar; 625 else 626 hc_entry->rmx_rttvar = ((uint64_t)hc_entry->rmx_rttvar + 627 (uint64_t)hcml->rmx_rttvar) / 2; 628 TCPSTAT_INC(tcps_cachedrttvar); 629 } 630 if (hcml->rmx_ssthresh != 0) { 631 if (hc_entry->rmx_ssthresh == 0) 632 hc_entry->rmx_ssthresh = hcml->rmx_ssthresh; 633 else 634 hc_entry->rmx_ssthresh = 635 (hc_entry->rmx_ssthresh + hcml->rmx_ssthresh) / 2; 636 TCPSTAT_INC(tcps_cachedssthresh); 637 } 638 if (hcml->rmx_cwnd != 0) { 639 if (hc_entry->rmx_cwnd == 0) 640 hc_entry->rmx_cwnd = hcml->rmx_cwnd; 641 else 642 hc_entry->rmx_cwnd = ((uint64_t)hc_entry->rmx_cwnd + 643 (uint64_t)hcml->rmx_cwnd) / 2; 644 /* TCPSTAT_INC(tcps_cachedcwnd); */ 645 } 646 if (hcml->rmx_sendpipe != 0) { 647 if (hc_entry->rmx_sendpipe == 0) 648 hc_entry->rmx_sendpipe = hcml->rmx_sendpipe; 649 else 650 hc_entry->rmx_sendpipe = 651 ((uint64_t)hc_entry->rmx_sendpipe + 652 (uint64_t)hcml->rmx_sendpipe) /2; 653 /* TCPSTAT_INC(tcps_cachedsendpipe); */ 654 } 655 if (hcml->rmx_recvpipe != 0) { 656 if (hc_entry->rmx_recvpipe == 0) 657 hc_entry->rmx_recvpipe = hcml->rmx_recvpipe; 658 else 659 hc_entry->rmx_recvpipe = 660 ((uint64_t)hc_entry->rmx_recvpipe + 661 (uint64_t)hcml->rmx_recvpipe) /2; 662 /* TCPSTAT_INC(tcps_cachedrecvpipe); */ 663 } 664 665 TAILQ_REMOVE(&hc_entry->rmx_head->hch_bucket, hc_entry, rmx_q); 666 TAILQ_INSERT_HEAD(&hc_entry->rmx_head->hch_bucket, hc_entry, rmx_q); 667 THC_UNLOCK(&hc_entry->rmx_head->hch_mtx); 668 } 669 670 /* 671 * Sysctl function: prints the list and values of all hostcache entries in 672 * unsorted order. 673 */ 674 static int 675 sysctl_tcp_hc_list(SYSCTL_HANDLER_ARGS) 676 { 677 const int linesize = 128; 678 struct sbuf sb; 679 int i, error, len; 680 struct hc_metrics *hc_entry; 681 char ip4buf[INET_ADDRSTRLEN]; 682 #ifdef INET6 683 char ip6buf[INET6_ADDRSTRLEN]; 684 #endif 685 686 if (jailed_without_vnet(curthread->td_ucred) != 0) 687 return (EPERM); 688 689 /* Optimize Buffer length query by sbin/sysctl */ 690 if (req->oldptr == NULL) { 691 len = (atomic_load_int(&V_tcp_hostcache.cache_count) + 1) * 692 linesize; 693 return (SYSCTL_OUT(req, NULL, len)); 694 } 695 696 error = sysctl_wire_old_buffer(req, 0); 697 if (error != 0) { 698 return(error); 699 } 700 701 /* Use a buffer sized for one full bucket */ 702 sbuf_new_for_sysctl(&sb, NULL, V_tcp_hostcache.bucket_limit * 703 linesize, req); 704 705 sbuf_printf(&sb, 706 "\nIP address MTU SSTRESH RTT RTTVAR " 707 " CWND SENDPIPE RECVPIPE " 708 #ifdef TCP_HC_COUNTERS 709 "HITS UPD " 710 #endif 711 "EXP\n"); 712 sbuf_drain(&sb); 713 714 #define msec(u) (((u) + 500) / 1000) 715 for (i = 0; i < V_tcp_hostcache.hashsize; i++) { 716 THC_LOCK(&V_tcp_hostcache.hashbase[i].hch_mtx); 717 TAILQ_FOREACH(hc_entry, &V_tcp_hostcache.hashbase[i].hch_bucket, 718 rmx_q) { 719 sbuf_printf(&sb, 720 "%-15s %5u %8u %6lums %6lums %8u %8u %8u " 721 #ifdef TCP_HC_COUNTERS 722 "%4lu %4lu " 723 #endif 724 "%4i\n", 725 hc_entry->ip4.s_addr ? 726 inet_ntoa_r(hc_entry->ip4, ip4buf) : 727 #ifdef INET6 728 ip6_sprintf(ip6buf, &hc_entry->ip6), 729 #else 730 "IPv6?", 731 #endif 732 hc_entry->rmx_mtu, 733 hc_entry->rmx_ssthresh, 734 msec((u_long)hc_entry->rmx_rtt * 735 (RTM_RTTUNIT / (hz * TCP_RTT_SCALE))), 736 msec((u_long)hc_entry->rmx_rttvar * 737 (RTM_RTTUNIT / (hz * TCP_RTTVAR_SCALE))), 738 hc_entry->rmx_cwnd, 739 hc_entry->rmx_sendpipe, 740 hc_entry->rmx_recvpipe, 741 #ifdef TCP_HC_COUNTERS 742 hc_entry->rmx_hits, 743 hc_entry->rmx_updates, 744 #endif 745 hc_entry->rmx_expire); 746 } 747 THC_UNLOCK(&V_tcp_hostcache.hashbase[i].hch_mtx); 748 sbuf_drain(&sb); 749 } 750 #undef msec 751 error = sbuf_finish(&sb); 752 sbuf_delete(&sb); 753 return(error); 754 } 755 756 /* 757 * Sysctl function: prints a histogram of the hostcache hashbucket 758 * utilization. 759 */ 760 static int 761 sysctl_tcp_hc_histo(SYSCTL_HANDLER_ARGS) 762 { 763 const int linesize = 50; 764 struct sbuf sb; 765 int i, error; 766 int *histo; 767 u_int hch_length; 768 769 if (jailed_without_vnet(curthread->td_ucred) != 0) 770 return (EPERM); 771 772 histo = (int *)malloc(sizeof(int) * (V_tcp_hostcache.bucket_limit + 1), 773 M_TEMP, M_NOWAIT|M_ZERO); 774 if (histo == NULL) 775 return(ENOMEM); 776 777 for (i = 0; i < V_tcp_hostcache.hashsize; i++) { 778 hch_length = V_tcp_hostcache.hashbase[i].hch_length; 779 KASSERT(hch_length <= V_tcp_hostcache.bucket_limit, 780 ("tcp_hostcache: bucket limit exceeded at %u: %u", 781 i, hch_length)); 782 histo[hch_length]++; 783 } 784 785 /* Use a buffer for 16 lines */ 786 sbuf_new_for_sysctl(&sb, NULL, 16 * linesize, req); 787 788 sbuf_printf(&sb, "\nLength\tCount\n"); 789 for (i = 0; i <= V_tcp_hostcache.bucket_limit; i++) { 790 sbuf_printf(&sb, "%u\t%u\n", i, histo[i]); 791 } 792 error = sbuf_finish(&sb); 793 sbuf_delete(&sb); 794 free(histo, M_TEMP); 795 return(error); 796 } 797 798 /* 799 * Caller has to make sure the curvnet is set properly. 800 */ 801 static void 802 tcp_hc_purge_internal(int all) 803 { 804 struct hc_metrics *hc_entry, *hc_next; 805 int i; 806 807 for (i = 0; i < V_tcp_hostcache.hashsize; i++) { 808 THC_LOCK(&V_tcp_hostcache.hashbase[i].hch_mtx); 809 TAILQ_FOREACH_SAFE(hc_entry, 810 &V_tcp_hostcache.hashbase[i].hch_bucket, rmx_q, hc_next) { 811 KASSERT(V_tcp_hostcache.hashbase[i].hch_length > 0 && 812 V_tcp_hostcache.hashbase[i].hch_length <= 813 V_tcp_hostcache.bucket_limit, 814 ("tcp_hostcache: bucket length out of range at %u: %u", 815 i, V_tcp_hostcache.hashbase[i].hch_length)); 816 if (all || hc_entry->rmx_expire <= 0) { 817 TAILQ_REMOVE(&V_tcp_hostcache.hashbase[i].hch_bucket, 818 hc_entry, rmx_q); 819 uma_zfree(V_tcp_hostcache.zone, hc_entry); 820 V_tcp_hostcache.hashbase[i].hch_length--; 821 atomic_subtract_int(&V_tcp_hostcache.cache_count, 1); 822 } else 823 hc_entry->rmx_expire -= V_tcp_hostcache.prune; 824 } 825 THC_UNLOCK(&V_tcp_hostcache.hashbase[i].hch_mtx); 826 } 827 } 828 829 /* 830 * Expire and purge (old|all) entries in the tcp_hostcache. Runs 831 * periodically from the callout. 832 */ 833 static void 834 tcp_hc_purge(void *arg) 835 { 836 CURVNET_SET((struct vnet *) arg); 837 int all = 0; 838 839 if (V_tcp_hostcache.purgeall) { 840 if (V_tcp_hostcache.purgeall == 2) 841 V_tcp_hostcache.hashsalt = arc4random(); 842 all = 1; 843 V_tcp_hostcache.purgeall = 0; 844 } 845 846 tcp_hc_purge_internal(all); 847 848 callout_reset(&V_tcp_hc_callout, V_tcp_hostcache.prune * hz, 849 tcp_hc_purge, arg); 850 CURVNET_RESTORE(); 851 } 852 853 /* 854 * Expire and purge all entries in hostcache immediately. 855 */ 856 static int 857 sysctl_tcp_hc_purgenow(SYSCTL_HANDLER_ARGS) 858 { 859 int error, val; 860 861 val = 0; 862 error = sysctl_handle_int(oidp, &val, 0, req); 863 if (error || !req->newptr) 864 return (error); 865 866 if (val == 2) 867 V_tcp_hostcache.hashsalt = arc4random(); 868 tcp_hc_purge_internal(1); 869 870 callout_reset(&V_tcp_hc_callout, V_tcp_hostcache.prune * hz, 871 tcp_hc_purge, curvnet); 872 873 return (0); 874 } 875