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 94struct hc_head { 95 CK_SLIST_HEAD(hc_qhead, hc_metrics) hch_bucket; 96 u_int hch_length; 97 struct mtx hch_mtx; 98}; 99 100struct hc_metrics { 101 /* housekeeping */ 102 CK_SLIST_ENTRY(hc_metrics) rmx_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 rmx_mtu; /* MTU for this path */ 108 uint32_t rmx_ssthresh; /* outbound gateway buffer limit */ 109 uint32_t rmx_rtt; /* estimated round trip time */ 110 uint32_t rmx_rttvar; /* estimated rtt variance */ 111 uint32_t rmx_cwnd; /* congestion window */ 112 uint32_t rmx_sendpipe; /* outbound delay-bandwidth product */ 113 uint32_t rmx_recvpipe; /* inbound delay-bandwidth product */ 114 /* TCP hostcache internal data */ 115 int rmx_expire; /* lifetime for object */ 116#ifdef TCP_HC_COUNTERS 117 u_long rmx_hits; /* number of hits */ 118 u_long rmx_updates; /* number of updates */ 119#endif 120}; 121 122struct 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 143VNET_DEFINE_STATIC(struct tcp_hostcache, tcp_hostcache); 144#define V_tcp_hostcache VNET(tcp_hostcache) 145 146VNET_DEFINE_STATIC(struct callout, tcp_hc_callout); 147#define V_tcp_hc_callout VNET(tcp_hc_callout) 148 149static struct hc_metrics *tcp_hc_lookup(struct in_conninfo *); 150static int sysctl_tcp_hc_list(SYSCTL_HANDLER_ARGS); 151static int sysctl_tcp_hc_histo(SYSCTL_HANDLER_ARGS); 152static int sysctl_tcp_hc_purgenow(SYSCTL_HANDLER_ARGS); 153static void tcp_hc_purge_internal(int); 154static void tcp_hc_purge(void *); 155 156static SYSCTL_NODE(_net_inet_tcp, OID_AUTO, hostcache, 157 CTLFLAG_RW | CTLFLAG_MPSAFE, 0, 158 "TCP Host cache"); 159 160VNET_DEFINE(int, tcp_use_hostcache) = 1; 161#define V_tcp_use_hostcache VNET(tcp_use_hostcache) 162SYSCTL_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 166SYSCTL_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 170SYSCTL_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 174SYSCTL_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 178SYSCTL_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 182SYSCTL_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 186SYSCTL_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 190SYSCTL_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 194SYSCTL_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 199SYSCTL_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 204SYSCTL_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 209static 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 223void 224tcp_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 292void 293tcp_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 */ 314static bool 315tcp_hc_cmp(struct hc_metrics *hc_entry, 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 */ 336static struct hc_metrics * 337tcp_hc_lookup(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, rmx_q) 351 if (tcp_hc_cmp(hc_entry, inc)) 352 break; 353 354 if (hc_entry != NULL) { 355 if (atomic_load_int(&hc_entry->rmx_expire) != 356 V_tcp_hostcache.expire) 357 atomic_store_int(&hc_entry->rmx_expire, 358 V_tcp_hostcache.expire); 359#ifdef TCP_HC_COUNTERS 360 hc_entry->rmx_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 */ 373void 374tcp_hc_get(struct in_conninfo *inc, struct hc_metrics_lite *hc_metrics_lite) 375{ 376 struct hc_metrics *hc_entry; 377 378 if (!V_tcp_use_hostcache) { 379 bzero(hc_metrics_lite, sizeof(*hc_metrics_lite)); 380 return; 381 } 382 383 /* 384 * Find the right bucket. 385 */ 386 hc_entry = tcp_hc_lookup(inc); 387 388 /* 389 * If we don't have an existing object. 390 */ 391 if (hc_entry == NULL) { 392 bzero(hc_metrics_lite, sizeof(*hc_metrics_lite)); 393 return; 394 } 395 396 hc_metrics_lite->rmx_mtu = atomic_load_32(&hc_entry->rmx_mtu); 397 hc_metrics_lite->rmx_ssthresh = atomic_load_32(&hc_entry->rmx_ssthresh); 398 hc_metrics_lite->rmx_rtt = atomic_load_32(&hc_entry->rmx_rtt); 399 hc_metrics_lite->rmx_rttvar = atomic_load_32(&hc_entry->rmx_rttvar); 400 hc_metrics_lite->rmx_cwnd = atomic_load_32(&hc_entry->rmx_cwnd); 401 hc_metrics_lite->rmx_sendpipe = atomic_load_32(&hc_entry->rmx_sendpipe); 402 hc_metrics_lite->rmx_recvpipe = atomic_load_32(&hc_entry->rmx_recvpipe); 403 404 smr_exit(V_tcp_hostcache.smr); 405} 406 407/* 408 * External function: look up an entry in the hostcache and return the 409 * discovered path MTU. Returns 0 if no entry is found or value is not 410 * set. 411 */ 412uint32_t 413tcp_hc_getmtu(struct in_conninfo *inc) 414{ 415 struct hc_metrics *hc_entry; 416 uint32_t mtu; 417 418 if (!V_tcp_use_hostcache) 419 return (0); 420 421 hc_entry = tcp_hc_lookup(inc); 422 if (hc_entry == NULL) { 423 return (0); 424 } 425 426 mtu = atomic_load_32(&hc_entry->rmx_mtu); 427 smr_exit(V_tcp_hostcache.smr); 428 429 return (mtu); 430} 431 432/* 433 * External function: update the MTU value of an entry in the hostcache. 434 * Creates a new entry if none was found. 435 */ 436void 437tcp_hc_updatemtu(struct in_conninfo *inc, uint32_t mtu) 438{ 439 struct hc_metrics_lite hcml = { .rmx_mtu = mtu }; 440 441 return (tcp_hc_update(inc, &hcml)); 442} 443 444/* 445 * External function: update the TCP metrics of an entry in the hostcache. 446 * Creates a new entry if none was found. 447 */ 448void 449tcp_hc_update(struct in_conninfo *inc, struct hc_metrics_lite *hcml) 450{ 451 struct hc_head *hc_head; 452 struct hc_metrics *hc_entry, *hc_prev; 453 uint32_t v; 454 bool new; 455 456 if (!V_tcp_use_hostcache) 457 return; 458 459 hc_head = &V_tcp_hostcache.hashbase[HOSTCACHE_HASH(inc)]; 460 hc_prev = NULL; 461 462 THC_LOCK(hc_head); 463 CK_SLIST_FOREACH(hc_entry, &hc_head->hch_bucket, rmx_q) { 464 if (tcp_hc_cmp(hc_entry, inc)) 465 break; 466 if (CK_SLIST_NEXT(hc_entry, rmx_q) != NULL) 467 hc_prev = hc_entry; 468 } 469 470 if (hc_entry != NULL) { 471 if (atomic_load_int(&hc_entry->rmx_expire) != 472 V_tcp_hostcache.expire) 473 atomic_store_int(&hc_entry->rmx_expire, 474 V_tcp_hostcache.expire); 475#ifdef TCP_HC_COUNTERS 476 hc_entry->rmx_updates++; 477#endif 478 new = false; 479 } else { 480 /* 481 * Try to allocate a new entry. If the bucket limit is 482 * reached, delete the least-used element, located at the end 483 * of the CK_SLIST. During lookup we saved the pointer to 484 * the second to last element, in case if list has at least 2 485 * elements. This will allow to delete last element without 486 * extra traversal. 487 * 488 * Give up if the row is empty. 489 */ 490 if (hc_head->hch_length >= V_tcp_hostcache.bucket_limit || 491 atomic_load_int(&V_tcp_hostcache.cache_count) >= 492 V_tcp_hostcache.cache_limit) { 493 if (hc_prev != NULL) { 494 hc_entry = CK_SLIST_NEXT(hc_prev, rmx_q); 495 KASSERT(CK_SLIST_NEXT(hc_entry, rmx_q) == NULL, 496 ("%s: %p is not one to last", 497 __func__, hc_prev)); 498 CK_SLIST_REMOVE_AFTER(hc_prev, rmx_q); 499 } else if ((hc_entry = 500 CK_SLIST_FIRST(&hc_head->hch_bucket)) != NULL) { 501 KASSERT(CK_SLIST_NEXT(hc_entry, rmx_q) == NULL, 502 ("%s: %p is not the only element", 503 __func__, hc_entry)); 504 CK_SLIST_REMOVE_HEAD(&hc_head->hch_bucket, 505 rmx_q); 506 } else { 507 THC_UNLOCK(hc_head); 508 return; 509 } 510 KASSERT(hc_head->hch_length > 0 && 511 hc_head->hch_length <= V_tcp_hostcache.bucket_limit, 512 ("tcp_hostcache: bucket length violated at %p", 513 hc_head)); 514 hc_head->hch_length--; 515 atomic_subtract_int(&V_tcp_hostcache.cache_count, 1); 516 TCPSTAT_INC(tcps_hc_bucketoverflow); 517 uma_zfree_smr(V_tcp_hostcache.zone, hc_entry); 518 } 519 520 /* 521 * Allocate a new entry, or balk if not possible. 522 */ 523 hc_entry = uma_zalloc_smr(V_tcp_hostcache.zone, M_NOWAIT); 524 if (hc_entry == NULL) { 525 THC_UNLOCK(hc_head); 526 return; 527 } 528 529 /* 530 * Initialize basic information of hostcache entry. 531 */ 532 bzero(hc_entry, sizeof(*hc_entry)); 533 if (inc->inc_flags & INC_ISIPV6) { 534 hc_entry->ip6 = inc->inc6_faddr; 535 hc_entry->ip6_zoneid = inc->inc6_zoneid; 536 } else 537 hc_entry->ip4 = inc->inc_faddr; 538 hc_entry->rmx_expire = V_tcp_hostcache.expire; 539 new = true; 540 } 541 542 /* 543 * Fill in data. Use atomics, since an existing entry is 544 * accessible by readers in SMR section. 545 */ 546 if (hcml->rmx_mtu != 0) { 547 atomic_store_32(&hc_entry->rmx_mtu, hcml->rmx_mtu); 548 } 549 if (hcml->rmx_rtt != 0) { 550 if (hc_entry->rmx_rtt == 0) 551 v = hcml->rmx_rtt; 552 else 553 v = ((uint64_t)hc_entry->rmx_rtt + 554 (uint64_t)hcml->rmx_rtt) / 2; 555 atomic_store_32(&hc_entry->rmx_rtt, v); 556 TCPSTAT_INC(tcps_cachedrtt); 557 } 558 if (hcml->rmx_rttvar != 0) { 559 if (hc_entry->rmx_rttvar == 0) 560 v = hcml->rmx_rttvar; 561 else 562 v = ((uint64_t)hc_entry->rmx_rttvar + 563 (uint64_t)hcml->rmx_rttvar) / 2; 564 atomic_store_32(&hc_entry->rmx_rttvar, v); 565 TCPSTAT_INC(tcps_cachedrttvar); 566 } 567 if (hcml->rmx_ssthresh != 0) { 568 if (hc_entry->rmx_ssthresh == 0) 569 v = hcml->rmx_ssthresh; 570 else 571 v = (hc_entry->rmx_ssthresh + hcml->rmx_ssthresh) / 2; 572 atomic_store_32(&hc_entry->rmx_ssthresh, v); 573 TCPSTAT_INC(tcps_cachedssthresh); 574 } 575 if (hcml->rmx_cwnd != 0) { 576 if (hc_entry->rmx_cwnd == 0) 577 v = hcml->rmx_cwnd; 578 else 579 v = ((uint64_t)hc_entry->rmx_cwnd + 580 (uint64_t)hcml->rmx_cwnd) / 2; 581 atomic_store_32(&hc_entry->rmx_cwnd, v); 582 /* TCPSTAT_INC(tcps_cachedcwnd); */ 583 } 584 if (hcml->rmx_sendpipe != 0) { 585 if (hc_entry->rmx_sendpipe == 0) 586 v = hcml->rmx_sendpipe; 587 else 588 v = ((uint64_t)hc_entry->rmx_sendpipe + 589 (uint64_t)hcml->rmx_sendpipe) /2; 590 atomic_store_32(&hc_entry->rmx_sendpipe, v); 591 /* TCPSTAT_INC(tcps_cachedsendpipe); */ 592 } 593 if (hcml->rmx_recvpipe != 0) { 594 if (hc_entry->rmx_recvpipe == 0) 595 v = hcml->rmx_recvpipe; 596 else 597 v = ((uint64_t)hc_entry->rmx_recvpipe + 598 (uint64_t)hcml->rmx_recvpipe) /2; 599 atomic_store_32(&hc_entry->rmx_recvpipe, v); 600 /* TCPSTAT_INC(tcps_cachedrecvpipe); */ 601 } 602 603 /* 604 * Put it upfront. 605 */ 606 if (new) { 607 CK_SLIST_INSERT_HEAD(&hc_head->hch_bucket, hc_entry, rmx_q); 608 hc_head->hch_length++; 609 KASSERT(hc_head->hch_length <= V_tcp_hostcache.bucket_limit, 610 ("tcp_hostcache: bucket length too high at %p", hc_head)); 611 atomic_add_int(&V_tcp_hostcache.cache_count, 1); 612 TCPSTAT_INC(tcps_hc_added); 613 } else if (hc_entry != CK_SLIST_FIRST(&hc_head->hch_bucket)) { 614 KASSERT(CK_SLIST_NEXT(hc_prev, rmx_q) == hc_entry, 615 ("%s: %p next is not %p", __func__, hc_prev, hc_entry)); 616 CK_SLIST_REMOVE_AFTER(hc_prev, rmx_q); 617 CK_SLIST_INSERT_HEAD(&hc_head->hch_bucket, hc_entry, rmx_q); 618 } 619 THC_UNLOCK(hc_head); 620} 621 622/* 623 * Sysctl function: prints the list and values of all hostcache entries in 624 * unsorted order. 625 */ 626static int 627sysctl_tcp_hc_list(SYSCTL_HANDLER_ARGS) 628{ 629 const int linesize = 128; 630 struct sbuf sb; 631 int i, error, len; 632 struct hc_metrics *hc_entry; 633 char ip4buf[INET_ADDRSTRLEN]; 634#ifdef INET6 635 char ip6buf[INET6_ADDRSTRLEN]; 636#endif 637 638 if (jailed_without_vnet(curthread->td_ucred) != 0) 639 return (EPERM); 640 641 /* Optimize Buffer length query by sbin/sysctl */ 642 if (req->oldptr == NULL) { 643 len = (atomic_load_int(&V_tcp_hostcache.cache_count) + 1) * 644 linesize; 645 return (SYSCTL_OUT(req, NULL, len)); 646 } 647 648 error = sysctl_wire_old_buffer(req, 0); 649 if (error != 0) { 650 return(error); 651 } 652 653 /* Use a buffer sized for one full bucket */ 654 sbuf_new_for_sysctl(&sb, NULL, V_tcp_hostcache.bucket_limit * 655 linesize, req); 656 657 sbuf_printf(&sb, 658 "\nIP address MTU SSTRESH RTT RTTVAR " 659 " CWND SENDPIPE RECVPIPE " 660#ifdef TCP_HC_COUNTERS 661 "HITS UPD " 662#endif 663 "EXP\n"); 664 sbuf_drain(&sb); 665 666#define msec(u) (((u) + 500) / 1000) 667 for (i = 0; i < V_tcp_hostcache.hashsize; i++) { 668 THC_LOCK(&V_tcp_hostcache.hashbase[i]); 669 CK_SLIST_FOREACH(hc_entry, 670 &V_tcp_hostcache.hashbase[i].hch_bucket, rmx_q) { 671 sbuf_printf(&sb, 672 "%-15s %5u %8u %6lums %6lums %8u %8u %8u " 673#ifdef TCP_HC_COUNTERS 674 "%4lu %4lu " 675#endif 676 "%4i\n", 677 hc_entry->ip4.s_addr ? 678 inet_ntoa_r(hc_entry->ip4, ip4buf) : 679#ifdef INET6 680 ip6_sprintf(ip6buf, &hc_entry->ip6), 681#else 682 "IPv6?", 683#endif 684 hc_entry->rmx_mtu, 685 hc_entry->rmx_ssthresh, 686 msec((u_long)hc_entry->rmx_rtt * 687 (RTM_RTTUNIT / (hz * TCP_RTT_SCALE))), 688 msec((u_long)hc_entry->rmx_rttvar * 689 (RTM_RTTUNIT / (hz * TCP_RTTVAR_SCALE))), 690 hc_entry->rmx_cwnd, 691 hc_entry->rmx_sendpipe, 692 hc_entry->rmx_recvpipe, 693#ifdef TCP_HC_COUNTERS 694 hc_entry->rmx_hits, 695 hc_entry->rmx_updates, 696#endif 697 hc_entry->rmx_expire); 698 } 699 THC_UNLOCK(&V_tcp_hostcache.hashbase[i]); 700 sbuf_drain(&sb); 701 } 702#undef msec 703 error = sbuf_finish(&sb); 704 sbuf_delete(&sb); 705 return(error); 706} 707 708/* 709 * Sysctl function: prints a histogram of the hostcache hashbucket 710 * utilization. 711 */ 712static int 713sysctl_tcp_hc_histo(SYSCTL_HANDLER_ARGS) 714{ 715 const int linesize = 50; 716 struct sbuf sb; 717 int i, error; 718 int *histo; 719 u_int hch_length; 720 721 if (jailed_without_vnet(curthread->td_ucred) != 0) 722 return (EPERM); 723 724 histo = (int *)malloc(sizeof(int) * (V_tcp_hostcache.bucket_limit + 1), 725 M_TEMP, M_NOWAIT|M_ZERO); 726 if (histo == NULL) 727 return(ENOMEM); 728 729 for (i = 0; i < V_tcp_hostcache.hashsize; i++) { 730 hch_length = V_tcp_hostcache.hashbase[i].hch_length; 731 KASSERT(hch_length <= V_tcp_hostcache.bucket_limit, 732 ("tcp_hostcache: bucket limit exceeded at %u: %u", 733 i, hch_length)); 734 histo[hch_length]++; 735 } 736 737 /* Use a buffer for 16 lines */ 738 sbuf_new_for_sysctl(&sb, NULL, 16 * linesize, req); 739 740 sbuf_printf(&sb, "\nLength\tCount\n"); 741 for (i = 0; i <= V_tcp_hostcache.bucket_limit; i++) { 742 sbuf_printf(&sb, "%u\t%u\n", i, histo[i]); 743 } 744 error = sbuf_finish(&sb); 745 sbuf_delete(&sb); 746 free(histo, M_TEMP); 747 return(error); 748} 749 750/* 751 * Caller has to make sure the curvnet is set properly. 752 */ 753static void 754tcp_hc_purge_internal(int all) 755{ 756 struct hc_head *head; 757 struct hc_metrics *hc_entry, *hc_next, *hc_prev; 758 int i; 759 760 for (i = 0; i < V_tcp_hostcache.hashsize; i++) { 761 head = &V_tcp_hostcache.hashbase[i]; 762 hc_prev = NULL; 763 THC_LOCK(head); 764 CK_SLIST_FOREACH_SAFE(hc_entry, &head->hch_bucket, rmx_q, 765 hc_next) { 766 KASSERT(head->hch_length > 0 && head->hch_length <= 767 V_tcp_hostcache.bucket_limit, ("tcp_hostcache: " 768 "bucket length out of range at %u: %u", i, 769 head->hch_length)); 770 if (all || 771 atomic_load_int(&hc_entry->rmx_expire) <= 0) { 772 if (hc_prev != NULL) { 773 KASSERT(hc_entry == 774 CK_SLIST_NEXT(hc_prev, rmx_q), 775 ("%s: %p is not next to %p", 776 __func__, hc_entry, hc_prev)); 777 CK_SLIST_REMOVE_AFTER(hc_prev, rmx_q); 778 } else { 779 KASSERT(hc_entry == 780 CK_SLIST_FIRST(&head->hch_bucket), 781 ("%s: %p is not first", 782 __func__, hc_entry)); 783 CK_SLIST_REMOVE_HEAD(&head->hch_bucket, 784 rmx_q); 785 } 786 uma_zfree_smr(V_tcp_hostcache.zone, hc_entry); 787 head->hch_length--; 788 atomic_subtract_int(&V_tcp_hostcache.cache_count, 1); 789 } else { 790 atomic_subtract_int(&hc_entry->rmx_expire, 791 V_tcp_hostcache.prune); 792 hc_prev = hc_entry; 793 } 794 } 795 THC_UNLOCK(head); 796 } 797} 798 799/* 800 * Expire and purge (old|all) entries in the tcp_hostcache. Runs 801 * periodically from the callout. 802 */ 803static void 804tcp_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 */ 826static int 827sysctl_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