1 /*- 2 * SPDX-License-Identifier: BSD-3-Clause 3 * 4 * Copyright (c) 2002 Andre Oppermann, Internet Business Solutions AG 5 * Copyright (c) 2021 Gleb Smirnoff <glebius@FreeBSD.org> 6 * All rights reserved. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 3. The name of the author may not be used to endorse or promote 17 * products derived from this software without specific prior written 18 * permission. 19 * 20 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30 * SUCH DAMAGE. 31 */ 32 33 /* 34 * The tcp_hostcache moves the tcp-specific cached metrics from the routing 35 * table to a dedicated structure indexed by the remote IP address. It keeps 36 * information on the measured TCP parameters of past TCP sessions to allow 37 * better initial start values to be used with later connections to/from the 38 * same source. Depending on the network parameters (delay, max MTU, 39 * congestion window) between local and remote sites, this can lead to 40 * significant speed-ups for new TCP connections after the first one. 41 * 42 * Due to the tcp_hostcache, all TCP-specific metrics information in the 43 * routing table have been removed. The inpcb no longer keeps a pointer to 44 * the routing entry, and protocol-initiated route cloning has been removed 45 * as well. With these changes, the routing table has gone back to being 46 * more lightwight and only carries information related to packet forwarding. 47 * 48 * tcp_hostcache is designed for multiple concurrent access in SMP 49 * environments and high contention. It is a straight hash. Each bucket row 50 * is protected by its own lock for modification. Readers are protected by 51 * SMR. This puts certain restrictions on writers, e.g. a writer shall only 52 * insert a fully populated entry into a row. Writer can't reuse least used 53 * entry if a hash is full. Value updates for an entry shall be atomic. 54 * 55 * TCP stack(s) communication with tcp_hostcache() is done via KBI functions 56 * tcp_hc_*() and the hc_metrics_lite structure. 57 * 58 * Since tcp_hostcache is only caching information, there are no fatal 59 * consequences if we either can't allocate a new entry or have to drop 60 * an existing entry, or return somewhat stale information. 61 */ 62 63 /* 64 * Many thanks to jlemon for basic structure of tcp_syncache which is being 65 * followed here. 66 */ 67 68 #include <sys/cdefs.h> 69 #include "opt_inet6.h" 70 71 #include <sys/param.h> 72 #include <sys/systm.h> 73 #include <sys/hash.h> 74 #include <sys/jail.h> 75 #include <sys/kernel.h> 76 #include <sys/lock.h> 77 #include <sys/mutex.h> 78 #include <sys/malloc.h> 79 #include <sys/proc.h> 80 #include <sys/sbuf.h> 81 #include <sys/smr.h> 82 #include <sys/socket.h> 83 #include <sys/sysctl.h> 84 85 #include <net/vnet.h> 86 87 #include <netinet/in.h> 88 #include <netinet/in_pcb.h> 89 #include <netinet/tcp.h> 90 #include <netinet/tcp_var.h> 91 92 #include <vm/uma.h> 93 94 struct hc_head { 95 CK_SLIST_HEAD(hc_qhead, hc_metrics) hch_bucket; 96 u_int hch_length; 97 struct mtx hch_mtx; 98 }; 99 100 struct hc_metrics { 101 /* housekeeping */ 102 CK_SLIST_ENTRY(hc_metrics) hc_q; 103 struct in_addr ip4; /* IP address */ 104 struct in6_addr ip6; /* IP6 address */ 105 uint32_t ip6_zoneid; /* IPv6 scope zone id */ 106 /* endpoint specific values for tcp */ 107 uint32_t hc_mtu; /* MTU for this path */ 108 uint32_t hc_ssthresh; /* outbound gateway buffer limit */ 109 uint32_t hc_rtt; /* estimated round trip time */ 110 uint32_t hc_rttvar; /* estimated rtt variance */ 111 uint32_t hc_cwnd; /* congestion window */ 112 uint32_t hc_sendpipe; /* outbound delay-bandwidth product */ 113 uint32_t hc_recvpipe; /* inbound delay-bandwidth product */ 114 /* TCP hostcache internal data */ 115 int hc_expire; /* lifetime for object */ 116 #ifdef TCP_HC_COUNTERS 117 u_long hc_hits; /* number of hits */ 118 u_long hc_updates; /* number of updates */ 119 #endif 120 }; 121 122 struct tcp_hostcache { 123 struct hc_head *hashbase; 124 uma_zone_t zone; 125 smr_t smr; 126 u_int hashsize; 127 u_int hashmask; 128 u_int hashsalt; 129 u_int bucket_limit; 130 u_int cache_count; 131 u_int cache_limit; 132 int expire; 133 int prune; 134 int purgeall; 135 }; 136 137 /* Arbitrary values */ 138 #define TCP_HOSTCACHE_HASHSIZE 512 139 #define TCP_HOSTCACHE_BUCKETLIMIT 30 140 #define TCP_HOSTCACHE_EXPIRE 60*60 /* one hour */ 141 #define TCP_HOSTCACHE_PRUNE 5*60 /* every 5 minutes */ 142 143 VNET_DEFINE_STATIC(struct tcp_hostcache, tcp_hostcache); 144 #define V_tcp_hostcache VNET(tcp_hostcache) 145 146 VNET_DEFINE_STATIC(struct callout, tcp_hc_callout); 147 #define V_tcp_hc_callout VNET(tcp_hc_callout) 148 149 static struct hc_metrics *tcp_hc_lookup(const struct in_conninfo *); 150 static int sysctl_tcp_hc_list(SYSCTL_HANDLER_ARGS); 151 static int sysctl_tcp_hc_histo(SYSCTL_HANDLER_ARGS); 152 static int sysctl_tcp_hc_purgenow(SYSCTL_HANDLER_ARGS); 153 static void tcp_hc_purge_internal(int); 154 static void tcp_hc_purge(void *); 155 156 static SYSCTL_NODE(_net_inet_tcp, OID_AUTO, hostcache, 157 CTLFLAG_RW | CTLFLAG_MPSAFE, 0, 158 "TCP Host cache"); 159 160 VNET_DEFINE(int, tcp_use_hostcache) = 1; 161 #define V_tcp_use_hostcache VNET(tcp_use_hostcache) 162 SYSCTL_INT(_net_inet_tcp_hostcache, OID_AUTO, enable, CTLFLAG_VNET | CTLFLAG_RW, 163 &VNET_NAME(tcp_use_hostcache), 0, 164 "Enable the TCP hostcache"); 165 166 SYSCTL_UINT(_net_inet_tcp_hostcache, OID_AUTO, cachelimit, CTLFLAG_VNET | CTLFLAG_RDTUN, 167 &VNET_NAME(tcp_hostcache.cache_limit), 0, 168 "Overall entry limit for hostcache"); 169 170 SYSCTL_UINT(_net_inet_tcp_hostcache, OID_AUTO, hashsize, CTLFLAG_VNET | CTLFLAG_RDTUN, 171 &VNET_NAME(tcp_hostcache.hashsize), 0, 172 "Size of TCP hostcache hashtable"); 173 174 SYSCTL_UINT(_net_inet_tcp_hostcache, OID_AUTO, bucketlimit, 175 CTLFLAG_VNET | CTLFLAG_RDTUN, &VNET_NAME(tcp_hostcache.bucket_limit), 0, 176 "Per-bucket hash limit for hostcache"); 177 178 SYSCTL_UINT(_net_inet_tcp_hostcache, OID_AUTO, count, CTLFLAG_VNET | CTLFLAG_RD, 179 &VNET_NAME(tcp_hostcache.cache_count), 0, 180 "Current number of entries in hostcache"); 181 182 SYSCTL_INT(_net_inet_tcp_hostcache, OID_AUTO, expire, CTLFLAG_VNET | CTLFLAG_RW, 183 &VNET_NAME(tcp_hostcache.expire), 0, 184 "Expire time of TCP hostcache entries"); 185 186 SYSCTL_INT(_net_inet_tcp_hostcache, OID_AUTO, prune, CTLFLAG_VNET | CTLFLAG_RW, 187 &VNET_NAME(tcp_hostcache.prune), 0, 188 "Time between purge runs"); 189 190 SYSCTL_INT(_net_inet_tcp_hostcache, OID_AUTO, purge, CTLFLAG_VNET | CTLFLAG_RW, 191 &VNET_NAME(tcp_hostcache.purgeall), 0, 192 "Expire all entries on next purge run"); 193 194 SYSCTL_PROC(_net_inet_tcp_hostcache, OID_AUTO, list, 195 CTLTYPE_STRING | CTLFLAG_RD | CTLFLAG_SKIP | CTLFLAG_MPSAFE, 196 0, 0, sysctl_tcp_hc_list, "A", 197 "List of all hostcache entries"); 198 199 SYSCTL_PROC(_net_inet_tcp_hostcache, OID_AUTO, histo, 200 CTLTYPE_STRING | CTLFLAG_RD | CTLFLAG_SKIP | CTLFLAG_MPSAFE, 201 0, 0, sysctl_tcp_hc_histo, "A", 202 "Print a histogram of hostcache hashbucket utilization"); 203 204 SYSCTL_PROC(_net_inet_tcp_hostcache, OID_AUTO, purgenow, 205 CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_MPSAFE, 206 NULL, 0, sysctl_tcp_hc_purgenow, "I", 207 "Immediately purge all entries"); 208 209 static MALLOC_DEFINE(M_HOSTCACHE, "hostcache", "TCP hostcache"); 210 211 /* Use jenkins_hash32(), as in other parts of the tcp stack */ 212 #define HOSTCACHE_HASH(inc) \ 213 ((inc)->inc_flags & INC_ISIPV6) ? \ 214 (jenkins_hash32((inc)->inc6_faddr.s6_addr32, 4, \ 215 V_tcp_hostcache.hashsalt) & V_tcp_hostcache.hashmask) \ 216 : \ 217 (jenkins_hash32(&(inc)->inc_faddr.s_addr, 1, \ 218 V_tcp_hostcache.hashsalt) & V_tcp_hostcache.hashmask) 219 220 #define THC_LOCK(h) mtx_lock(&(h)->hch_mtx) 221 #define THC_UNLOCK(h) mtx_unlock(&(h)->hch_mtx) 222 223 void 224 tcp_hc_init(void) 225 { 226 u_int cache_limit; 227 int i; 228 229 /* 230 * Initialize hostcache structures. 231 */ 232 atomic_store_int(&V_tcp_hostcache.cache_count, 0); 233 V_tcp_hostcache.hashsize = TCP_HOSTCACHE_HASHSIZE; 234 V_tcp_hostcache.bucket_limit = TCP_HOSTCACHE_BUCKETLIMIT; 235 V_tcp_hostcache.expire = TCP_HOSTCACHE_EXPIRE; 236 V_tcp_hostcache.prune = TCP_HOSTCACHE_PRUNE; 237 V_tcp_hostcache.hashsalt = arc4random(); 238 239 TUNABLE_INT_FETCH("net.inet.tcp.hostcache.hashsize", 240 &V_tcp_hostcache.hashsize); 241 if (!powerof2(V_tcp_hostcache.hashsize)) { 242 printf("WARNING: hostcache hash size is not a power of 2.\n"); 243 V_tcp_hostcache.hashsize = TCP_HOSTCACHE_HASHSIZE; /* default */ 244 } 245 V_tcp_hostcache.hashmask = V_tcp_hostcache.hashsize - 1; 246 247 TUNABLE_INT_FETCH("net.inet.tcp.hostcache.bucketlimit", 248 &V_tcp_hostcache.bucket_limit); 249 250 cache_limit = V_tcp_hostcache.hashsize * V_tcp_hostcache.bucket_limit; 251 V_tcp_hostcache.cache_limit = cache_limit; 252 TUNABLE_INT_FETCH("net.inet.tcp.hostcache.cachelimit", 253 &V_tcp_hostcache.cache_limit); 254 if (V_tcp_hostcache.cache_limit > cache_limit) 255 V_tcp_hostcache.cache_limit = cache_limit; 256 257 /* 258 * Allocate the hash table. 259 */ 260 V_tcp_hostcache.hashbase = (struct hc_head *) 261 malloc(V_tcp_hostcache.hashsize * sizeof(struct hc_head), 262 M_HOSTCACHE, M_WAITOK | M_ZERO); 263 264 /* 265 * Initialize the hash buckets. 266 */ 267 for (i = 0; i < V_tcp_hostcache.hashsize; i++) { 268 CK_SLIST_INIT(&V_tcp_hostcache.hashbase[i].hch_bucket); 269 V_tcp_hostcache.hashbase[i].hch_length = 0; 270 mtx_init(&V_tcp_hostcache.hashbase[i].hch_mtx, "tcp_hc_entry", 271 NULL, MTX_DEF); 272 } 273 274 /* 275 * Allocate the hostcache entries. 276 */ 277 V_tcp_hostcache.zone = 278 uma_zcreate("hostcache", sizeof(struct hc_metrics), 279 NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, UMA_ZONE_SMR); 280 uma_zone_set_max(V_tcp_hostcache.zone, V_tcp_hostcache.cache_limit); 281 V_tcp_hostcache.smr = uma_zone_get_smr(V_tcp_hostcache.zone); 282 283 /* 284 * Set up periodic cache cleanup. 285 */ 286 callout_init(&V_tcp_hc_callout, 1); 287 callout_reset(&V_tcp_hc_callout, V_tcp_hostcache.prune * hz, 288 tcp_hc_purge, curvnet); 289 } 290 291 #ifdef VIMAGE 292 void 293 tcp_hc_destroy(void) 294 { 295 int i; 296 297 callout_drain(&V_tcp_hc_callout); 298 299 /* Purge all hc entries. */ 300 tcp_hc_purge_internal(1); 301 302 /* Free the uma zone and the allocated hash table. */ 303 uma_zdestroy(V_tcp_hostcache.zone); 304 305 for (i = 0; i < V_tcp_hostcache.hashsize; i++) 306 mtx_destroy(&V_tcp_hostcache.hashbase[i].hch_mtx); 307 free(V_tcp_hostcache.hashbase, M_HOSTCACHE); 308 } 309 #endif 310 311 /* 312 * Internal function: compare cache entry to a connection. 313 */ 314 static bool 315 tcp_hc_cmp(struct hc_metrics *hc_entry, const struct in_conninfo *inc) 316 { 317 318 if (inc->inc_flags & INC_ISIPV6) { 319 /* XXX: check ip6_zoneid */ 320 if (memcmp(&inc->inc6_faddr, &hc_entry->ip6, 321 sizeof(inc->inc6_faddr)) == 0) 322 return (true); 323 } else { 324 if (memcmp(&inc->inc_faddr, &hc_entry->ip4, 325 sizeof(inc->inc_faddr)) == 0) 326 return (true); 327 } 328 329 return (false); 330 } 331 332 /* 333 * Internal function: look up an entry in the hostcache for read. 334 * On success returns in SMR section. 335 */ 336 static struct hc_metrics * 337 tcp_hc_lookup(const struct in_conninfo *inc) 338 { 339 struct hc_head *hc_head; 340 struct hc_metrics *hc_entry; 341 342 KASSERT(inc != NULL, ("%s: NULL in_conninfo", __func__)); 343 344 hc_head = &V_tcp_hostcache.hashbase[HOSTCACHE_HASH(inc)]; 345 346 /* 347 * Iterate through entries in bucket row looking for a match. 348 */ 349 smr_enter(V_tcp_hostcache.smr); 350 CK_SLIST_FOREACH(hc_entry, &hc_head->hch_bucket, hc_q) 351 if (tcp_hc_cmp(hc_entry, inc)) 352 break; 353 354 if (hc_entry != NULL) { 355 if (atomic_load_int(&hc_entry->hc_expire) != 356 V_tcp_hostcache.expire) 357 atomic_store_int(&hc_entry->hc_expire, 358 V_tcp_hostcache.expire); 359 #ifdef TCP_HC_COUNTERS 360 hc_entry->hc_hits++; 361 #endif 362 } else 363 smr_exit(V_tcp_hostcache.smr); 364 365 return (hc_entry); 366 } 367 368 /* 369 * External function: look up an entry in the hostcache and fill out the 370 * supplied TCP metrics structure. Fills in NULL when no entry was found or 371 * a value is not set. 372 */ 373 void 374 tcp_hc_get(const struct in_conninfo *inc, 375 struct hc_metrics_lite *hc_metrics_lite) 376 { 377 struct hc_metrics *hc_entry; 378 379 if (!V_tcp_use_hostcache) { 380 bzero(hc_metrics_lite, sizeof(*hc_metrics_lite)); 381 return; 382 } 383 384 /* 385 * Find the right bucket. 386 */ 387 hc_entry = tcp_hc_lookup(inc); 388 389 /* 390 * If we don't have an existing object. 391 */ 392 if (hc_entry == NULL) { 393 bzero(hc_metrics_lite, sizeof(*hc_metrics_lite)); 394 return; 395 } 396 397 hc_metrics_lite->hc_mtu = atomic_load_32(&hc_entry->hc_mtu); 398 hc_metrics_lite->hc_ssthresh = atomic_load_32(&hc_entry->hc_ssthresh); 399 hc_metrics_lite->hc_rtt = atomic_load_32(&hc_entry->hc_rtt); 400 hc_metrics_lite->hc_rttvar = atomic_load_32(&hc_entry->hc_rttvar); 401 hc_metrics_lite->hc_cwnd = atomic_load_32(&hc_entry->hc_cwnd); 402 hc_metrics_lite->hc_sendpipe = atomic_load_32(&hc_entry->hc_sendpipe); 403 hc_metrics_lite->hc_recvpipe = atomic_load_32(&hc_entry->hc_recvpipe); 404 405 smr_exit(V_tcp_hostcache.smr); 406 } 407 408 /* 409 * External function: look up an entry in the hostcache and return the 410 * discovered path MTU. Returns 0 if no entry is found or value is not 411 * set. 412 */ 413 uint32_t 414 tcp_hc_getmtu(const struct in_conninfo *inc) 415 { 416 struct hc_metrics *hc_entry; 417 uint32_t mtu; 418 419 if (!V_tcp_use_hostcache) 420 return (0); 421 422 hc_entry = tcp_hc_lookup(inc); 423 if (hc_entry == NULL) { 424 return (0); 425 } 426 427 mtu = atomic_load_32(&hc_entry->hc_mtu); 428 smr_exit(V_tcp_hostcache.smr); 429 430 return (mtu); 431 } 432 433 /* 434 * External function: update the MTU value of an entry in the hostcache. 435 * Creates a new entry if none was found. 436 */ 437 void 438 tcp_hc_updatemtu(const struct in_conninfo *inc, uint32_t mtu) 439 { 440 struct hc_metrics_lite hcml = { .hc_mtu = mtu }; 441 442 return (tcp_hc_update(inc, &hcml)); 443 } 444 445 /* 446 * External function: update the TCP metrics of an entry in the hostcache. 447 * Creates a new entry if none was found. 448 */ 449 void 450 tcp_hc_update(const struct in_conninfo *inc, struct hc_metrics_lite *hcml) 451 { 452 struct hc_head *hc_head; 453 struct hc_metrics *hc_entry, *hc_prev; 454 uint32_t v; 455 bool new; 456 457 if (!V_tcp_use_hostcache) 458 return; 459 460 hc_head = &V_tcp_hostcache.hashbase[HOSTCACHE_HASH(inc)]; 461 hc_prev = NULL; 462 463 THC_LOCK(hc_head); 464 CK_SLIST_FOREACH(hc_entry, &hc_head->hch_bucket, hc_q) { 465 if (tcp_hc_cmp(hc_entry, inc)) 466 break; 467 if (CK_SLIST_NEXT(hc_entry, hc_q) != NULL) 468 hc_prev = hc_entry; 469 } 470 471 if (hc_entry != NULL) { 472 if (atomic_load_int(&hc_entry->hc_expire) != 473 V_tcp_hostcache.expire) 474 atomic_store_int(&hc_entry->hc_expire, 475 V_tcp_hostcache.expire); 476 #ifdef TCP_HC_COUNTERS 477 hc_entry->hc_updates++; 478 #endif 479 new = false; 480 } else { 481 /* 482 * Try to allocate a new entry. If the bucket limit is 483 * reached, delete the least-used element, located at the end 484 * of the CK_SLIST. During lookup we saved the pointer to 485 * the second to last element, in case if list has at least 2 486 * elements. This will allow to delete last element without 487 * extra traversal. 488 * 489 * Give up if the row is empty. 490 */ 491 if (hc_head->hch_length >= V_tcp_hostcache.bucket_limit || 492 atomic_load_int(&V_tcp_hostcache.cache_count) >= 493 V_tcp_hostcache.cache_limit) { 494 if (hc_prev != NULL) { 495 hc_entry = CK_SLIST_NEXT(hc_prev, hc_q); 496 KASSERT(CK_SLIST_NEXT(hc_entry, hc_q) == NULL, 497 ("%s: %p is not one to last", 498 __func__, hc_prev)); 499 CK_SLIST_REMOVE_AFTER(hc_prev, hc_q); 500 } else if ((hc_entry = 501 CK_SLIST_FIRST(&hc_head->hch_bucket)) != NULL) { 502 KASSERT(CK_SLIST_NEXT(hc_entry, hc_q) == NULL, 503 ("%s: %p is not the only element", 504 __func__, hc_entry)); 505 CK_SLIST_REMOVE_HEAD(&hc_head->hch_bucket, 506 hc_q); 507 } else { 508 THC_UNLOCK(hc_head); 509 return; 510 } 511 KASSERT(hc_head->hch_length > 0 && 512 hc_head->hch_length <= V_tcp_hostcache.bucket_limit, 513 ("tcp_hostcache: bucket length violated at %p", 514 hc_head)); 515 hc_head->hch_length--; 516 atomic_subtract_int(&V_tcp_hostcache.cache_count, 1); 517 TCPSTAT_INC(tcps_hc_bucketoverflow); 518 uma_zfree_smr(V_tcp_hostcache.zone, hc_entry); 519 } 520 521 /* 522 * Allocate a new entry, or balk if not possible. 523 */ 524 hc_entry = uma_zalloc_smr(V_tcp_hostcache.zone, M_NOWAIT); 525 if (hc_entry == NULL) { 526 THC_UNLOCK(hc_head); 527 return; 528 } 529 530 /* 531 * Initialize basic information of hostcache entry. 532 */ 533 bzero(hc_entry, sizeof(*hc_entry)); 534 if (inc->inc_flags & INC_ISIPV6) { 535 hc_entry->ip6 = inc->inc6_faddr; 536 hc_entry->ip6_zoneid = inc->inc6_zoneid; 537 } else 538 hc_entry->ip4 = inc->inc_faddr; 539 hc_entry->hc_expire = V_tcp_hostcache.expire; 540 new = true; 541 } 542 543 /* 544 * Fill in data. Use atomics, since an existing entry is 545 * accessible by readers in SMR section. 546 */ 547 if (hcml->hc_mtu != 0) { 548 atomic_store_32(&hc_entry->hc_mtu, hcml->hc_mtu); 549 } 550 if (hcml->hc_rtt != 0) { 551 if (hc_entry->hc_rtt == 0) 552 v = hcml->hc_rtt; 553 else 554 v = ((uint64_t)hc_entry->hc_rtt + 555 (uint64_t)hcml->hc_rtt) / 2; 556 atomic_store_32(&hc_entry->hc_rtt, v); 557 TCPSTAT_INC(tcps_cachedrtt); 558 } 559 if (hcml->hc_rttvar != 0) { 560 if (hc_entry->hc_rttvar == 0) 561 v = hcml->hc_rttvar; 562 else 563 v = ((uint64_t)hc_entry->hc_rttvar + 564 (uint64_t)hcml->hc_rttvar) / 2; 565 atomic_store_32(&hc_entry->hc_rttvar, v); 566 TCPSTAT_INC(tcps_cachedrttvar); 567 } 568 if (hcml->hc_ssthresh != 0) { 569 if (hc_entry->hc_ssthresh == 0) 570 v = hcml->hc_ssthresh; 571 else 572 v = (hc_entry->hc_ssthresh + hcml->hc_ssthresh) / 2; 573 atomic_store_32(&hc_entry->hc_ssthresh, v); 574 TCPSTAT_INC(tcps_cachedssthresh); 575 } 576 if (hcml->hc_cwnd != 0) { 577 if (hc_entry->hc_cwnd == 0) 578 v = hcml->hc_cwnd; 579 else 580 v = ((uint64_t)hc_entry->hc_cwnd + 581 (uint64_t)hcml->hc_cwnd) / 2; 582 atomic_store_32(&hc_entry->hc_cwnd, v); 583 /* TCPSTAT_INC(tcps_cachedcwnd); */ 584 } 585 if (hcml->hc_sendpipe != 0) { 586 if (hc_entry->hc_sendpipe == 0) 587 v = hcml->hc_sendpipe; 588 else 589 v = ((uint64_t)hc_entry->hc_sendpipe + 590 (uint64_t)hcml->hc_sendpipe) /2; 591 atomic_store_32(&hc_entry->hc_sendpipe, v); 592 /* TCPSTAT_INC(tcps_cachedsendpipe); */ 593 } 594 if (hcml->hc_recvpipe != 0) { 595 if (hc_entry->hc_recvpipe == 0) 596 v = hcml->hc_recvpipe; 597 else 598 v = ((uint64_t)hc_entry->hc_recvpipe + 599 (uint64_t)hcml->hc_recvpipe) /2; 600 atomic_store_32(&hc_entry->hc_recvpipe, v); 601 /* TCPSTAT_INC(tcps_cachedrecvpipe); */ 602 } 603 604 /* 605 * Put it upfront. 606 */ 607 if (new) { 608 CK_SLIST_INSERT_HEAD(&hc_head->hch_bucket, hc_entry, hc_q); 609 hc_head->hch_length++; 610 KASSERT(hc_head->hch_length <= V_tcp_hostcache.bucket_limit, 611 ("tcp_hostcache: bucket length too high at %p", hc_head)); 612 atomic_add_int(&V_tcp_hostcache.cache_count, 1); 613 TCPSTAT_INC(tcps_hc_added); 614 } else if (hc_entry != CK_SLIST_FIRST(&hc_head->hch_bucket)) { 615 KASSERT(CK_SLIST_NEXT(hc_prev, hc_q) == hc_entry, 616 ("%s: %p next is not %p", __func__, hc_prev, hc_entry)); 617 CK_SLIST_REMOVE_AFTER(hc_prev, hc_q); 618 CK_SLIST_INSERT_HEAD(&hc_head->hch_bucket, hc_entry, hc_q); 619 } 620 THC_UNLOCK(hc_head); 621 } 622 623 /* 624 * Sysctl function: prints the list and values of all hostcache entries in 625 * unsorted order. 626 */ 627 static int 628 sysctl_tcp_hc_list(SYSCTL_HANDLER_ARGS) 629 { 630 const int linesize = 128; 631 struct sbuf sb; 632 int i, error, len; 633 struct hc_metrics *hc_entry; 634 char ip4buf[INET_ADDRSTRLEN]; 635 #ifdef INET6 636 char ip6buf[INET6_ADDRSTRLEN]; 637 #endif 638 639 if (jailed_without_vnet(curthread->td_ucred) != 0) 640 return (EPERM); 641 642 /* Optimize Buffer length query by sbin/sysctl */ 643 if (req->oldptr == NULL) { 644 len = (atomic_load_int(&V_tcp_hostcache.cache_count) + 1) * 645 linesize; 646 return (SYSCTL_OUT(req, NULL, len)); 647 } 648 649 error = sysctl_wire_old_buffer(req, 0); 650 if (error != 0) { 651 return(error); 652 } 653 654 /* Use a buffer sized for one full bucket */ 655 sbuf_new_for_sysctl(&sb, NULL, V_tcp_hostcache.bucket_limit * 656 linesize, req); 657 658 sbuf_printf(&sb, 659 "\nIP address MTU SSTRESH RTT RTTVAR " 660 " CWND SENDPIPE RECVPIPE " 661 #ifdef TCP_HC_COUNTERS 662 "HITS UPD " 663 #endif 664 "EXP\n"); 665 sbuf_drain(&sb); 666 667 #define msec(u) (((u) + 500) / 1000) 668 for (i = 0; i < V_tcp_hostcache.hashsize; i++) { 669 THC_LOCK(&V_tcp_hostcache.hashbase[i]); 670 CK_SLIST_FOREACH(hc_entry, 671 &V_tcp_hostcache.hashbase[i].hch_bucket, hc_q) { 672 sbuf_printf(&sb, 673 "%-15s %5u %8u %6lums %6lums %8u %8u %8u " 674 #ifdef TCP_HC_COUNTERS 675 "%4lu %4lu " 676 #endif 677 "%4i\n", 678 hc_entry->ip4.s_addr ? 679 inet_ntoa_r(hc_entry->ip4, ip4buf) : 680 #ifdef INET6 681 ip6_sprintf(ip6buf, &hc_entry->ip6), 682 #else 683 "IPv6?", 684 #endif 685 hc_entry->hc_mtu, 686 hc_entry->hc_ssthresh, 687 msec((u_long)hc_entry->hc_rtt * 688 (RTM_RTTUNIT / (hz * TCP_RTT_SCALE))), 689 msec((u_long)hc_entry->hc_rttvar * 690 (RTM_RTTUNIT / (hz * TCP_RTTVAR_SCALE))), 691 hc_entry->hc_cwnd, 692 hc_entry->hc_sendpipe, 693 hc_entry->hc_recvpipe, 694 #ifdef TCP_HC_COUNTERS 695 hc_entry->hc_hits, 696 hc_entry->hc_updates, 697 #endif 698 hc_entry->hc_expire); 699 } 700 THC_UNLOCK(&V_tcp_hostcache.hashbase[i]); 701 sbuf_drain(&sb); 702 } 703 #undef msec 704 error = sbuf_finish(&sb); 705 sbuf_delete(&sb); 706 return(error); 707 } 708 709 /* 710 * Sysctl function: prints a histogram of the hostcache hashbucket 711 * utilization. 712 */ 713 static int 714 sysctl_tcp_hc_histo(SYSCTL_HANDLER_ARGS) 715 { 716 const int linesize = 50; 717 struct sbuf sb; 718 int i, error; 719 int *histo; 720 u_int hch_length; 721 722 if (jailed_without_vnet(curthread->td_ucred) != 0) 723 return (EPERM); 724 725 histo = (int *)malloc(sizeof(int) * (V_tcp_hostcache.bucket_limit + 1), 726 M_TEMP, M_NOWAIT|M_ZERO); 727 if (histo == NULL) 728 return(ENOMEM); 729 730 for (i = 0; i < V_tcp_hostcache.hashsize; i++) { 731 hch_length = V_tcp_hostcache.hashbase[i].hch_length; 732 KASSERT(hch_length <= V_tcp_hostcache.bucket_limit, 733 ("tcp_hostcache: bucket limit exceeded at %u: %u", 734 i, hch_length)); 735 histo[hch_length]++; 736 } 737 738 /* Use a buffer for 16 lines */ 739 sbuf_new_for_sysctl(&sb, NULL, 16 * linesize, req); 740 741 sbuf_printf(&sb, "\nLength\tCount\n"); 742 for (i = 0; i <= V_tcp_hostcache.bucket_limit; i++) { 743 sbuf_printf(&sb, "%u\t%u\n", i, histo[i]); 744 } 745 error = sbuf_finish(&sb); 746 sbuf_delete(&sb); 747 free(histo, M_TEMP); 748 return(error); 749 } 750 751 /* 752 * Caller has to make sure the curvnet is set properly. 753 */ 754 static void 755 tcp_hc_purge_internal(int all) 756 { 757 struct hc_head *head; 758 struct hc_metrics *hc_entry, *hc_next, *hc_prev; 759 int i; 760 761 for (i = 0; i < V_tcp_hostcache.hashsize; i++) { 762 head = &V_tcp_hostcache.hashbase[i]; 763 hc_prev = NULL; 764 THC_LOCK(head); 765 CK_SLIST_FOREACH_SAFE(hc_entry, &head->hch_bucket, hc_q, 766 hc_next) { 767 KASSERT(head->hch_length > 0 && head->hch_length <= 768 V_tcp_hostcache.bucket_limit, ("tcp_hostcache: " 769 "bucket length out of range at %u: %u", i, 770 head->hch_length)); 771 if (all || 772 atomic_load_int(&hc_entry->hc_expire) <= 0) { 773 if (hc_prev != NULL) { 774 KASSERT(hc_entry == 775 CK_SLIST_NEXT(hc_prev, hc_q), 776 ("%s: %p is not next to %p", 777 __func__, hc_entry, hc_prev)); 778 CK_SLIST_REMOVE_AFTER(hc_prev, hc_q); 779 } else { 780 KASSERT(hc_entry == 781 CK_SLIST_FIRST(&head->hch_bucket), 782 ("%s: %p is not first", 783 __func__, hc_entry)); 784 CK_SLIST_REMOVE_HEAD(&head->hch_bucket, 785 hc_q); 786 } 787 uma_zfree_smr(V_tcp_hostcache.zone, hc_entry); 788 head->hch_length--; 789 atomic_subtract_int(&V_tcp_hostcache.cache_count, 1); 790 } else { 791 atomic_subtract_int(&hc_entry->hc_expire, 792 V_tcp_hostcache.prune); 793 hc_prev = hc_entry; 794 } 795 } 796 THC_UNLOCK(head); 797 } 798 } 799 800 /* 801 * Expire and purge (old|all) entries in the tcp_hostcache. Runs 802 * periodically from the callout. 803 */ 804 static void 805 tcp_hc_purge(void *arg) 806 { 807 CURVNET_SET((struct vnet *) arg); 808 int all = 0; 809 810 if (V_tcp_hostcache.purgeall) { 811 if (V_tcp_hostcache.purgeall == 2) 812 V_tcp_hostcache.hashsalt = arc4random(); 813 all = 1; 814 V_tcp_hostcache.purgeall = 0; 815 } 816 817 tcp_hc_purge_internal(all); 818 819 callout_reset(&V_tcp_hc_callout, V_tcp_hostcache.prune * hz, 820 tcp_hc_purge, arg); 821 CURVNET_RESTORE(); 822 } 823 824 /* 825 * Expire and purge all entries in hostcache immediately. 826 */ 827 static int 828 sysctl_tcp_hc_purgenow(SYSCTL_HANDLER_ARGS) 829 { 830 int error, val; 831 832 val = 0; 833 error = sysctl_handle_int(oidp, &val, 0, req); 834 if (error || !req->newptr) 835 return (error); 836 837 if (val == 2) 838 V_tcp_hostcache.hashsalt = arc4random(); 839 tcp_hc_purge_internal(1); 840 841 callout_reset(&V_tcp_hc_callout, V_tcp_hostcache.prune * hz, 842 tcp_hc_purge, curvnet); 843 844 return (0); 845 } 846