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(h) mtx_lock(&(h)->hch_mtx) 226 #define THC_UNLOCK(h) mtx_unlock(&(h)->hch_mtx) 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 KASSERT(inc != NULL, ("%s: NULL in_conninfo", __func__)); 329 330 /* 331 * Hash the foreign ip address. 332 */ 333 if (inc->inc_flags & INC_ISIPV6) 334 hash = HOSTCACHE_HASH6(&inc->inc6_faddr); 335 else 336 hash = HOSTCACHE_HASH(&inc->inc_faddr); 337 338 hc_head = &V_tcp_hostcache.hashbase[hash]; 339 340 /* 341 * Acquire lock for this bucket row; we release the lock if we don't 342 * find an entry, otherwise the caller has to unlock after he is 343 * done. 344 */ 345 THC_LOCK(hc_head); 346 347 /* 348 * Iterate through entries in bucket row looking for a match. 349 */ 350 TAILQ_FOREACH(hc_entry, &hc_head->hch_bucket, rmx_q) { 351 if (inc->inc_flags & INC_ISIPV6) { 352 /* XXX: check ip6_zoneid */ 353 if (memcmp(&inc->inc6_faddr, &hc_entry->ip6, 354 sizeof(inc->inc6_faddr)) == 0) 355 goto found; 356 } else { 357 if (memcmp(&inc->inc_faddr, &hc_entry->ip4, 358 sizeof(inc->inc_faddr)) == 0) 359 goto found; 360 } 361 } 362 363 /* 364 * We were unsuccessful and didn't find anything. 365 */ 366 THC_UNLOCK(hc_head); 367 return (NULL); 368 369 found: 370 #ifdef TCP_HC_COUNTERS 371 if (update) 372 hc_entry->rmx_updates++; 373 else 374 hc_entry->rmx_hits++; 375 #endif 376 hc_entry->rmx_expire = V_tcp_hostcache.expire; 377 378 return (hc_entry); 379 } 380 381 /* 382 * Internal function: insert an entry into the hostcache or return NULL if 383 * unable to allocate a new one. 384 * 385 * If an entry has been returned, the caller becomes responsible for 386 * unlocking the bucket row after he is done reading/modifying the entry. 387 */ 388 static struct hc_metrics * 389 tcp_hc_insert(struct in_conninfo *inc) 390 { 391 int hash; 392 struct hc_head *hc_head; 393 struct hc_metrics *hc_entry; 394 395 KASSERT(inc != NULL, ("%s: NULL in_conninfo", __func__)); 396 397 /* 398 * Hash the foreign ip address. 399 */ 400 if (inc->inc_flags & INC_ISIPV6) 401 hash = HOSTCACHE_HASH6(&inc->inc6_faddr); 402 else 403 hash = HOSTCACHE_HASH(&inc->inc_faddr); 404 405 hc_head = &V_tcp_hostcache.hashbase[hash]; 406 407 /* 408 * Acquire lock for this bucket row; we release the lock if we don't 409 * find an entry, otherwise the caller has to unlock after he is 410 * done. 411 */ 412 THC_LOCK(hc_head); 413 414 /* 415 * If the bucket limit is reached, reuse the least-used element. 416 */ 417 if (hc_head->hch_length >= V_tcp_hostcache.bucket_limit || 418 atomic_load_int(&V_tcp_hostcache.cache_count) >= V_tcp_hostcache.cache_limit) { 419 hc_entry = TAILQ_LAST(&hc_head->hch_bucket, hc_qhead); 420 /* 421 * At first we were dropping the last element, just to 422 * reacquire it in the next two lines again, which isn't very 423 * efficient. Instead just reuse the least used element. 424 * We may drop something that is still "in-use" but we can be 425 * "lossy". 426 * Just give up if this bucket row is empty and we don't have 427 * anything to replace. 428 */ 429 if (hc_entry == NULL) { 430 THC_UNLOCK(hc_head); 431 return (NULL); 432 } 433 TAILQ_REMOVE(&hc_head->hch_bucket, hc_entry, rmx_q); 434 KASSERT(V_tcp_hostcache.hashbase[hash].hch_length > 0 && 435 V_tcp_hostcache.hashbase[hash].hch_length <= 436 V_tcp_hostcache.bucket_limit, 437 ("tcp_hostcache: bucket length range violated at %u: %u", 438 hash, V_tcp_hostcache.hashbase[hash].hch_length)); 439 V_tcp_hostcache.hashbase[hash].hch_length--; 440 atomic_subtract_int(&V_tcp_hostcache.cache_count, 1); 441 TCPSTAT_INC(tcps_hc_bucketoverflow); 442 #if 0 443 uma_zfree(V_tcp_hostcache.zone, hc_entry); 444 #endif 445 } else { 446 /* 447 * Allocate a new entry, or balk if not possible. 448 */ 449 hc_entry = uma_zalloc(V_tcp_hostcache.zone, M_NOWAIT); 450 if (hc_entry == NULL) { 451 THC_UNLOCK(hc_head); 452 return (NULL); 453 } 454 } 455 456 /* 457 * Initialize basic information of hostcache entry. 458 */ 459 bzero(hc_entry, sizeof(*hc_entry)); 460 if (inc->inc_flags & INC_ISIPV6) { 461 hc_entry->ip6 = inc->inc6_faddr; 462 hc_entry->ip6_zoneid = inc->inc6_zoneid; 463 } else 464 hc_entry->ip4 = inc->inc_faddr; 465 hc_entry->rmx_head = hc_head; 466 hc_entry->rmx_expire = V_tcp_hostcache.expire; 467 468 /* 469 * Put it upfront. 470 */ 471 TAILQ_INSERT_HEAD(&hc_head->hch_bucket, hc_entry, rmx_q); 472 V_tcp_hostcache.hashbase[hash].hch_length++; 473 KASSERT(V_tcp_hostcache.hashbase[hash].hch_length < 474 V_tcp_hostcache.bucket_limit, 475 ("tcp_hostcache: bucket length too high at %u: %u", 476 hash, V_tcp_hostcache.hashbase[hash].hch_length)); 477 atomic_add_int(&V_tcp_hostcache.cache_count, 1); 478 TCPSTAT_INC(tcps_hc_added); 479 480 return (hc_entry); 481 } 482 483 /* 484 * External function: look up an entry in the hostcache and fill out the 485 * supplied TCP metrics structure. Fills in NULL when no entry was found or 486 * a value is not set. 487 */ 488 void 489 tcp_hc_get(struct in_conninfo *inc, struct hc_metrics_lite *hc_metrics_lite) 490 { 491 struct hc_metrics *hc_entry; 492 493 if (!V_tcp_use_hostcache) { 494 bzero(hc_metrics_lite, sizeof(*hc_metrics_lite)); 495 return; 496 } 497 498 /* 499 * Find the right bucket. 500 */ 501 hc_entry = tcp_hc_lookup(inc, false); 502 503 /* 504 * If we don't have an existing object. 505 */ 506 if (hc_entry == NULL) { 507 bzero(hc_metrics_lite, sizeof(*hc_metrics_lite)); 508 return; 509 } 510 511 hc_metrics_lite->rmx_mtu = hc_entry->rmx_mtu; 512 hc_metrics_lite->rmx_ssthresh = hc_entry->rmx_ssthresh; 513 hc_metrics_lite->rmx_rtt = hc_entry->rmx_rtt; 514 hc_metrics_lite->rmx_rttvar = hc_entry->rmx_rttvar; 515 hc_metrics_lite->rmx_cwnd = hc_entry->rmx_cwnd; 516 hc_metrics_lite->rmx_sendpipe = hc_entry->rmx_sendpipe; 517 hc_metrics_lite->rmx_recvpipe = hc_entry->rmx_recvpipe; 518 519 /* 520 * Unlock bucket row. 521 */ 522 THC_UNLOCK(hc_entry->rmx_head); 523 } 524 525 /* 526 * External function: look up an entry in the hostcache and return the 527 * discovered path MTU. Returns 0 if no entry is found or value is not 528 * set. 529 */ 530 uint32_t 531 tcp_hc_getmtu(struct in_conninfo *inc) 532 { 533 struct hc_metrics *hc_entry; 534 uint32_t mtu; 535 536 if (!V_tcp_use_hostcache) 537 return (0); 538 539 hc_entry = tcp_hc_lookup(inc, false); 540 if (hc_entry == NULL) { 541 return (0); 542 } 543 544 mtu = hc_entry->rmx_mtu; 545 THC_UNLOCK(hc_entry->rmx_head); 546 return (mtu); 547 } 548 549 /* 550 * External function: update the MTU value of an entry in the hostcache. 551 * Creates a new entry if none was found. 552 */ 553 void 554 tcp_hc_updatemtu(struct in_conninfo *inc, uint32_t mtu) 555 { 556 struct hc_metrics_lite hcml = { .rmx_mtu = mtu }; 557 558 return (tcp_hc_update(inc, &hcml)); 559 } 560 561 /* 562 * External function: update the TCP metrics of an entry in the hostcache. 563 * Creates a new entry if none was found. 564 */ 565 void 566 tcp_hc_update(struct in_conninfo *inc, struct hc_metrics_lite *hcml) 567 { 568 struct hc_metrics *hc_entry; 569 570 if (!V_tcp_use_hostcache) 571 return; 572 573 hc_entry = tcp_hc_lookup(inc, true); 574 if (hc_entry == NULL) { 575 hc_entry = tcp_hc_insert(inc); 576 if (hc_entry == NULL) 577 return; 578 } 579 580 if (hcml->rmx_mtu != 0) { 581 hc_entry->rmx_mtu = hcml->rmx_mtu; 582 } 583 if (hcml->rmx_rtt != 0) { 584 if (hc_entry->rmx_rtt == 0) 585 hc_entry->rmx_rtt = hcml->rmx_rtt; 586 else 587 hc_entry->rmx_rtt = ((uint64_t)hc_entry->rmx_rtt + 588 (uint64_t)hcml->rmx_rtt) / 2; 589 TCPSTAT_INC(tcps_cachedrtt); 590 } 591 if (hcml->rmx_rttvar != 0) { 592 if (hc_entry->rmx_rttvar == 0) 593 hc_entry->rmx_rttvar = hcml->rmx_rttvar; 594 else 595 hc_entry->rmx_rttvar = ((uint64_t)hc_entry->rmx_rttvar + 596 (uint64_t)hcml->rmx_rttvar) / 2; 597 TCPSTAT_INC(tcps_cachedrttvar); 598 } 599 if (hcml->rmx_ssthresh != 0) { 600 if (hc_entry->rmx_ssthresh == 0) 601 hc_entry->rmx_ssthresh = hcml->rmx_ssthresh; 602 else 603 hc_entry->rmx_ssthresh = 604 (hc_entry->rmx_ssthresh + hcml->rmx_ssthresh) / 2; 605 TCPSTAT_INC(tcps_cachedssthresh); 606 } 607 if (hcml->rmx_cwnd != 0) { 608 if (hc_entry->rmx_cwnd == 0) 609 hc_entry->rmx_cwnd = hcml->rmx_cwnd; 610 else 611 hc_entry->rmx_cwnd = ((uint64_t)hc_entry->rmx_cwnd + 612 (uint64_t)hcml->rmx_cwnd) / 2; 613 /* TCPSTAT_INC(tcps_cachedcwnd); */ 614 } 615 if (hcml->rmx_sendpipe != 0) { 616 if (hc_entry->rmx_sendpipe == 0) 617 hc_entry->rmx_sendpipe = hcml->rmx_sendpipe; 618 else 619 hc_entry->rmx_sendpipe = 620 ((uint64_t)hc_entry->rmx_sendpipe + 621 (uint64_t)hcml->rmx_sendpipe) /2; 622 /* TCPSTAT_INC(tcps_cachedsendpipe); */ 623 } 624 if (hcml->rmx_recvpipe != 0) { 625 if (hc_entry->rmx_recvpipe == 0) 626 hc_entry->rmx_recvpipe = hcml->rmx_recvpipe; 627 else 628 hc_entry->rmx_recvpipe = 629 ((uint64_t)hc_entry->rmx_recvpipe + 630 (uint64_t)hcml->rmx_recvpipe) /2; 631 /* TCPSTAT_INC(tcps_cachedrecvpipe); */ 632 } 633 634 TAILQ_REMOVE(&hc_entry->rmx_head->hch_bucket, hc_entry, rmx_q); 635 TAILQ_INSERT_HEAD(&hc_entry->rmx_head->hch_bucket, hc_entry, rmx_q); 636 THC_UNLOCK(hc_entry->rmx_head); 637 } 638 639 /* 640 * Sysctl function: prints the list and values of all hostcache entries in 641 * unsorted order. 642 */ 643 static int 644 sysctl_tcp_hc_list(SYSCTL_HANDLER_ARGS) 645 { 646 const int linesize = 128; 647 struct sbuf sb; 648 int i, error, len; 649 struct hc_metrics *hc_entry; 650 char ip4buf[INET_ADDRSTRLEN]; 651 #ifdef INET6 652 char ip6buf[INET6_ADDRSTRLEN]; 653 #endif 654 655 if (jailed_without_vnet(curthread->td_ucred) != 0) 656 return (EPERM); 657 658 /* Optimize Buffer length query by sbin/sysctl */ 659 if (req->oldptr == NULL) { 660 len = (atomic_load_int(&V_tcp_hostcache.cache_count) + 1) * 661 linesize; 662 return (SYSCTL_OUT(req, NULL, len)); 663 } 664 665 error = sysctl_wire_old_buffer(req, 0); 666 if (error != 0) { 667 return(error); 668 } 669 670 /* Use a buffer sized for one full bucket */ 671 sbuf_new_for_sysctl(&sb, NULL, V_tcp_hostcache.bucket_limit * 672 linesize, req); 673 674 sbuf_printf(&sb, 675 "\nIP address MTU SSTRESH RTT RTTVAR " 676 " CWND SENDPIPE RECVPIPE " 677 #ifdef TCP_HC_COUNTERS 678 "HITS UPD " 679 #endif 680 "EXP\n"); 681 sbuf_drain(&sb); 682 683 #define msec(u) (((u) + 500) / 1000) 684 for (i = 0; i < V_tcp_hostcache.hashsize; i++) { 685 THC_LOCK(&V_tcp_hostcache.hashbase[i]); 686 TAILQ_FOREACH(hc_entry, &V_tcp_hostcache.hashbase[i].hch_bucket, 687 rmx_q) { 688 sbuf_printf(&sb, 689 "%-15s %5u %8u %6lums %6lums %8u %8u %8u " 690 #ifdef TCP_HC_COUNTERS 691 "%4lu %4lu " 692 #endif 693 "%4i\n", 694 hc_entry->ip4.s_addr ? 695 inet_ntoa_r(hc_entry->ip4, ip4buf) : 696 #ifdef INET6 697 ip6_sprintf(ip6buf, &hc_entry->ip6), 698 #else 699 "IPv6?", 700 #endif 701 hc_entry->rmx_mtu, 702 hc_entry->rmx_ssthresh, 703 msec((u_long)hc_entry->rmx_rtt * 704 (RTM_RTTUNIT / (hz * TCP_RTT_SCALE))), 705 msec((u_long)hc_entry->rmx_rttvar * 706 (RTM_RTTUNIT / (hz * TCP_RTTVAR_SCALE))), 707 hc_entry->rmx_cwnd, 708 hc_entry->rmx_sendpipe, 709 hc_entry->rmx_recvpipe, 710 #ifdef TCP_HC_COUNTERS 711 hc_entry->rmx_hits, 712 hc_entry->rmx_updates, 713 #endif 714 hc_entry->rmx_expire); 715 } 716 THC_UNLOCK(&V_tcp_hostcache.hashbase[i]); 717 sbuf_drain(&sb); 718 } 719 #undef msec 720 error = sbuf_finish(&sb); 721 sbuf_delete(&sb); 722 return(error); 723 } 724 725 /* 726 * Sysctl function: prints a histogram of the hostcache hashbucket 727 * utilization. 728 */ 729 static int 730 sysctl_tcp_hc_histo(SYSCTL_HANDLER_ARGS) 731 { 732 const int linesize = 50; 733 struct sbuf sb; 734 int i, error; 735 int *histo; 736 u_int hch_length; 737 738 if (jailed_without_vnet(curthread->td_ucred) != 0) 739 return (EPERM); 740 741 histo = (int *)malloc(sizeof(int) * (V_tcp_hostcache.bucket_limit + 1), 742 M_TEMP, M_NOWAIT|M_ZERO); 743 if (histo == NULL) 744 return(ENOMEM); 745 746 for (i = 0; i < V_tcp_hostcache.hashsize; i++) { 747 hch_length = V_tcp_hostcache.hashbase[i].hch_length; 748 KASSERT(hch_length <= V_tcp_hostcache.bucket_limit, 749 ("tcp_hostcache: bucket limit exceeded at %u: %u", 750 i, hch_length)); 751 histo[hch_length]++; 752 } 753 754 /* Use a buffer for 16 lines */ 755 sbuf_new_for_sysctl(&sb, NULL, 16 * linesize, req); 756 757 sbuf_printf(&sb, "\nLength\tCount\n"); 758 for (i = 0; i <= V_tcp_hostcache.bucket_limit; i++) { 759 sbuf_printf(&sb, "%u\t%u\n", i, histo[i]); 760 } 761 error = sbuf_finish(&sb); 762 sbuf_delete(&sb); 763 free(histo, M_TEMP); 764 return(error); 765 } 766 767 /* 768 * Caller has to make sure the curvnet is set properly. 769 */ 770 static void 771 tcp_hc_purge_internal(int all) 772 { 773 struct hc_metrics *hc_entry, *hc_next; 774 int i; 775 776 for (i = 0; i < V_tcp_hostcache.hashsize; i++) { 777 THC_LOCK(&V_tcp_hostcache.hashbase[i]); 778 TAILQ_FOREACH_SAFE(hc_entry, 779 &V_tcp_hostcache.hashbase[i].hch_bucket, rmx_q, hc_next) { 780 KASSERT(V_tcp_hostcache.hashbase[i].hch_length > 0 && 781 V_tcp_hostcache.hashbase[i].hch_length <= 782 V_tcp_hostcache.bucket_limit, ("tcp_hostcache: " 783 "bucket length out of range at %u: %u", 784 i, V_tcp_hostcache.hashbase[i].hch_length)); 785 if (all || hc_entry->rmx_expire <= 0) { 786 TAILQ_REMOVE( 787 &V_tcp_hostcache.hashbase[i].hch_bucket, 788 hc_entry, rmx_q); 789 uma_zfree(V_tcp_hostcache.zone, hc_entry); 790 V_tcp_hostcache.hashbase[i].hch_length--; 791 atomic_subtract_int(&V_tcp_hostcache.cache_count, 1); 792 } else 793 hc_entry->rmx_expire -= V_tcp_hostcache.prune; 794 } 795 THC_UNLOCK(&V_tcp_hostcache.hashbase[i]); 796 } 797 } 798 799 /* 800 * Expire and purge (old|all) entries in the tcp_hostcache. Runs 801 * periodically from the callout. 802 */ 803 static void 804 tcp_hc_purge(void *arg) 805 { 806 CURVNET_SET((struct vnet *) arg); 807 int all = 0; 808 809 if (V_tcp_hostcache.purgeall) { 810 if (V_tcp_hostcache.purgeall == 2) 811 V_tcp_hostcache.hashsalt = arc4random(); 812 all = 1; 813 V_tcp_hostcache.purgeall = 0; 814 } 815 816 tcp_hc_purge_internal(all); 817 818 callout_reset(&V_tcp_hc_callout, V_tcp_hostcache.prune * hz, 819 tcp_hc_purge, arg); 820 CURVNET_RESTORE(); 821 } 822 823 /* 824 * Expire and purge all entries in hostcache immediately. 825 */ 826 static int 827 sysctl_tcp_hc_purgenow(SYSCTL_HANDLER_ARGS) 828 { 829 int error, val; 830 831 val = 0; 832 error = sysctl_handle_int(oidp, &val, 0, req); 833 if (error || !req->newptr) 834 return (error); 835 836 if (val == 2) 837 V_tcp_hostcache.hashsalt = arc4random(); 838 tcp_hc_purge_internal(1); 839 840 callout_reset(&V_tcp_hc_callout, V_tcp_hostcache.prune * hz, 841 tcp_hc_purge, curvnet); 842 843 return (0); 844 } 845