1#include <linux/rcupdate.h> 2#include <linux/spinlock.h> 3#include <linux/jiffies.h> 4#include <linux/module.h> 5#include <linux/cache.h> 6#include <linux/slab.h> 7#include <linux/init.h> 8#include <linux/tcp.h> 9#include <linux/hash.h> 10#include <linux/tcp_metrics.h> 11#include <linux/vmalloc.h> 12 13#include <net/inet_connection_sock.h> 14#include <net/net_namespace.h> 15#include <net/request_sock.h> 16#include <net/inetpeer.h> 17#include <net/sock.h> 18#include <net/ipv6.h> 19#include <net/dst.h> 20#include <net/tcp.h> 21#include <net/genetlink.h> 22 23int sysctl_tcp_nometrics_save __read_mostly; 24 25static struct tcp_metrics_block *__tcp_get_metrics(const struct inetpeer_addr *saddr, 26 const struct inetpeer_addr *daddr, 27 struct net *net, unsigned int hash); 28 29struct tcp_fastopen_metrics { 30 u16 mss; 31 u16 syn_loss:10; /* Recurring Fast Open SYN losses */ 32 unsigned long last_syn_loss; /* Last Fast Open SYN loss */ 33 struct tcp_fastopen_cookie cookie; 34}; 35 36/* TCP_METRIC_MAX includes 2 extra fields for userspace compatibility 37 * Kernel only stores RTT and RTTVAR in usec resolution 38 */ 39#define TCP_METRIC_MAX_KERNEL (TCP_METRIC_MAX - 2) 40 41struct tcp_metrics_block { 42 struct tcp_metrics_block __rcu *tcpm_next; 43 struct inetpeer_addr tcpm_saddr; 44 struct inetpeer_addr tcpm_daddr; 45 unsigned long tcpm_stamp; 46 u32 tcpm_ts; 47 u32 tcpm_ts_stamp; 48 u32 tcpm_lock; 49 u32 tcpm_vals[TCP_METRIC_MAX_KERNEL + 1]; 50 struct tcp_fastopen_metrics tcpm_fastopen; 51 52 struct rcu_head rcu_head; 53}; 54 55static bool tcp_metric_locked(struct tcp_metrics_block *tm, 56 enum tcp_metric_index idx) 57{ 58 return tm->tcpm_lock & (1 << idx); 59} 60 61static u32 tcp_metric_get(struct tcp_metrics_block *tm, 62 enum tcp_metric_index idx) 63{ 64 return tm->tcpm_vals[idx]; 65} 66 67static void tcp_metric_set(struct tcp_metrics_block *tm, 68 enum tcp_metric_index idx, 69 u32 val) 70{ 71 tm->tcpm_vals[idx] = val; 72} 73 74static bool addr_same(const struct inetpeer_addr *a, 75 const struct inetpeer_addr *b) 76{ 77 const struct in6_addr *a6, *b6; 78 79 if (a->family != b->family) 80 return false; 81 if (a->family == AF_INET) 82 return a->addr.a4 == b->addr.a4; 83 84 a6 = (const struct in6_addr *) &a->addr.a6[0]; 85 b6 = (const struct in6_addr *) &b->addr.a6[0]; 86 87 return ipv6_addr_equal(a6, b6); 88} 89 90struct tcpm_hash_bucket { 91 struct tcp_metrics_block __rcu *chain; 92}; 93 94static DEFINE_SPINLOCK(tcp_metrics_lock); 95 96static void tcpm_suck_dst(struct tcp_metrics_block *tm, 97 const struct dst_entry *dst, 98 bool fastopen_clear) 99{ 100 u32 msval; 101 u32 val; 102 103 tm->tcpm_stamp = jiffies; 104 105 val = 0; 106 if (dst_metric_locked(dst, RTAX_RTT)) 107 val |= 1 << TCP_METRIC_RTT; 108 if (dst_metric_locked(dst, RTAX_RTTVAR)) 109 val |= 1 << TCP_METRIC_RTTVAR; 110 if (dst_metric_locked(dst, RTAX_SSTHRESH)) 111 val |= 1 << TCP_METRIC_SSTHRESH; 112 if (dst_metric_locked(dst, RTAX_CWND)) 113 val |= 1 << TCP_METRIC_CWND; 114 if (dst_metric_locked(dst, RTAX_REORDERING)) 115 val |= 1 << TCP_METRIC_REORDERING; 116 tm->tcpm_lock = val; 117 118 msval = dst_metric_raw(dst, RTAX_RTT); 119 tm->tcpm_vals[TCP_METRIC_RTT] = msval * USEC_PER_MSEC; 120 121 msval = dst_metric_raw(dst, RTAX_RTTVAR); 122 tm->tcpm_vals[TCP_METRIC_RTTVAR] = msval * USEC_PER_MSEC; 123 tm->tcpm_vals[TCP_METRIC_SSTHRESH] = dst_metric_raw(dst, RTAX_SSTHRESH); 124 tm->tcpm_vals[TCP_METRIC_CWND] = dst_metric_raw(dst, RTAX_CWND); 125 tm->tcpm_vals[TCP_METRIC_REORDERING] = dst_metric_raw(dst, RTAX_REORDERING); 126 tm->tcpm_ts = 0; 127 tm->tcpm_ts_stamp = 0; 128 if (fastopen_clear) { 129 tm->tcpm_fastopen.mss = 0; 130 tm->tcpm_fastopen.syn_loss = 0; 131 tm->tcpm_fastopen.cookie.len = 0; 132 } 133} 134 135#define TCP_METRICS_TIMEOUT (60 * 60 * HZ) 136 137static void tcpm_check_stamp(struct tcp_metrics_block *tm, struct dst_entry *dst) 138{ 139 if (tm && unlikely(time_after(jiffies, tm->tcpm_stamp + TCP_METRICS_TIMEOUT))) 140 tcpm_suck_dst(tm, dst, false); 141} 142 143#define TCP_METRICS_RECLAIM_DEPTH 5 144#define TCP_METRICS_RECLAIM_PTR (struct tcp_metrics_block *) 0x1UL 145 146static struct tcp_metrics_block *tcpm_new(struct dst_entry *dst, 147 struct inetpeer_addr *saddr, 148 struct inetpeer_addr *daddr, 149 unsigned int hash) 150{ 151 struct tcp_metrics_block *tm; 152 struct net *net; 153 bool reclaim = false; 154 155 spin_lock_bh(&tcp_metrics_lock); 156 net = dev_net(dst->dev); 157 158 /* While waiting for the spin-lock the cache might have been populated 159 * with this entry and so we have to check again. 160 */ 161 tm = __tcp_get_metrics(saddr, daddr, net, hash); 162 if (tm == TCP_METRICS_RECLAIM_PTR) { 163 reclaim = true; 164 tm = NULL; 165 } 166 if (tm) { 167 tcpm_check_stamp(tm, dst); 168 goto out_unlock; 169 } 170 171 if (unlikely(reclaim)) { 172 struct tcp_metrics_block *oldest; 173 174 oldest = rcu_dereference(net->ipv4.tcp_metrics_hash[hash].chain); 175 for (tm = rcu_dereference(oldest->tcpm_next); tm; 176 tm = rcu_dereference(tm->tcpm_next)) { 177 if (time_before(tm->tcpm_stamp, oldest->tcpm_stamp)) 178 oldest = tm; 179 } 180 tm = oldest; 181 } else { 182 tm = kmalloc(sizeof(*tm), GFP_ATOMIC); 183 if (!tm) 184 goto out_unlock; 185 } 186 tm->tcpm_saddr = *saddr; 187 tm->tcpm_daddr = *daddr; 188 189 tcpm_suck_dst(tm, dst, true); 190 191 if (likely(!reclaim)) { 192 tm->tcpm_next = net->ipv4.tcp_metrics_hash[hash].chain; 193 rcu_assign_pointer(net->ipv4.tcp_metrics_hash[hash].chain, tm); 194 } 195 196out_unlock: 197 spin_unlock_bh(&tcp_metrics_lock); 198 return tm; 199} 200 201static struct tcp_metrics_block *tcp_get_encode(struct tcp_metrics_block *tm, int depth) 202{ 203 if (tm) 204 return tm; 205 if (depth > TCP_METRICS_RECLAIM_DEPTH) 206 return TCP_METRICS_RECLAIM_PTR; 207 return NULL; 208} 209 210static struct tcp_metrics_block *__tcp_get_metrics(const struct inetpeer_addr *saddr, 211 const struct inetpeer_addr *daddr, 212 struct net *net, unsigned int hash) 213{ 214 struct tcp_metrics_block *tm; 215 int depth = 0; 216 217 for (tm = rcu_dereference(net->ipv4.tcp_metrics_hash[hash].chain); tm; 218 tm = rcu_dereference(tm->tcpm_next)) { 219 if (addr_same(&tm->tcpm_saddr, saddr) && 220 addr_same(&tm->tcpm_daddr, daddr)) 221 break; 222 depth++; 223 } 224 return tcp_get_encode(tm, depth); 225} 226 227static struct tcp_metrics_block *__tcp_get_metrics_req(struct request_sock *req, 228 struct dst_entry *dst) 229{ 230 struct tcp_metrics_block *tm; 231 struct inetpeer_addr saddr, daddr; 232 unsigned int hash; 233 struct net *net; 234 235 saddr.family = req->rsk_ops->family; 236 daddr.family = req->rsk_ops->family; 237 switch (daddr.family) { 238 case AF_INET: 239 saddr.addr.a4 = inet_rsk(req)->ir_loc_addr; 240 daddr.addr.a4 = inet_rsk(req)->ir_rmt_addr; 241 hash = (__force unsigned int) daddr.addr.a4; 242 break; 243#if IS_ENABLED(CONFIG_IPV6) 244 case AF_INET6: 245 *(struct in6_addr *)saddr.addr.a6 = inet_rsk(req)->ir_v6_loc_addr; 246 *(struct in6_addr *)daddr.addr.a6 = inet_rsk(req)->ir_v6_rmt_addr; 247 hash = ipv6_addr_hash(&inet_rsk(req)->ir_v6_rmt_addr); 248 break; 249#endif 250 default: 251 return NULL; 252 } 253 254 net = dev_net(dst->dev); 255 hash = hash_32(hash, net->ipv4.tcp_metrics_hash_log); 256 257 for (tm = rcu_dereference(net->ipv4.tcp_metrics_hash[hash].chain); tm; 258 tm = rcu_dereference(tm->tcpm_next)) { 259 if (addr_same(&tm->tcpm_saddr, &saddr) && 260 addr_same(&tm->tcpm_daddr, &daddr)) 261 break; 262 } 263 tcpm_check_stamp(tm, dst); 264 return tm; 265} 266 267static struct tcp_metrics_block *__tcp_get_metrics_tw(struct inet_timewait_sock *tw) 268{ 269 struct tcp_metrics_block *tm; 270 struct inetpeer_addr saddr, daddr; 271 unsigned int hash; 272 struct net *net; 273 274 if (tw->tw_family == AF_INET) { 275 saddr.family = AF_INET; 276 saddr.addr.a4 = tw->tw_rcv_saddr; 277 daddr.family = AF_INET; 278 daddr.addr.a4 = tw->tw_daddr; 279 hash = (__force unsigned int) daddr.addr.a4; 280 } 281#if IS_ENABLED(CONFIG_IPV6) 282 else if (tw->tw_family == AF_INET6) { 283 if (ipv6_addr_v4mapped(&tw->tw_v6_daddr)) { 284 saddr.family = AF_INET; 285 saddr.addr.a4 = tw->tw_rcv_saddr; 286 daddr.family = AF_INET; 287 daddr.addr.a4 = tw->tw_daddr; 288 hash = (__force unsigned int) daddr.addr.a4; 289 } else { 290 saddr.family = AF_INET6; 291 *(struct in6_addr *)saddr.addr.a6 = tw->tw_v6_rcv_saddr; 292 daddr.family = AF_INET6; 293 *(struct in6_addr *)daddr.addr.a6 = tw->tw_v6_daddr; 294 hash = ipv6_addr_hash(&tw->tw_v6_daddr); 295 } 296 } 297#endif 298 else 299 return NULL; 300 301 net = twsk_net(tw); 302 hash = hash_32(hash, net->ipv4.tcp_metrics_hash_log); 303 304 for (tm = rcu_dereference(net->ipv4.tcp_metrics_hash[hash].chain); tm; 305 tm = rcu_dereference(tm->tcpm_next)) { 306 if (addr_same(&tm->tcpm_saddr, &saddr) && 307 addr_same(&tm->tcpm_daddr, &daddr)) 308 break; 309 } 310 return tm; 311} 312 313static struct tcp_metrics_block *tcp_get_metrics(struct sock *sk, 314 struct dst_entry *dst, 315 bool create) 316{ 317 struct tcp_metrics_block *tm; 318 struct inetpeer_addr saddr, daddr; 319 unsigned int hash; 320 struct net *net; 321 322 if (sk->sk_family == AF_INET) { 323 saddr.family = AF_INET; 324 saddr.addr.a4 = inet_sk(sk)->inet_saddr; 325 daddr.family = AF_INET; 326 daddr.addr.a4 = inet_sk(sk)->inet_daddr; 327 hash = (__force unsigned int) daddr.addr.a4; 328 } 329#if IS_ENABLED(CONFIG_IPV6) 330 else if (sk->sk_family == AF_INET6) { 331 if (ipv6_addr_v4mapped(&sk->sk_v6_daddr)) { 332 saddr.family = AF_INET; 333 saddr.addr.a4 = inet_sk(sk)->inet_saddr; 334 daddr.family = AF_INET; 335 daddr.addr.a4 = inet_sk(sk)->inet_daddr; 336 hash = (__force unsigned int) daddr.addr.a4; 337 } else { 338 saddr.family = AF_INET6; 339 *(struct in6_addr *)saddr.addr.a6 = sk->sk_v6_rcv_saddr; 340 daddr.family = AF_INET6; 341 *(struct in6_addr *)daddr.addr.a6 = sk->sk_v6_daddr; 342 hash = ipv6_addr_hash(&sk->sk_v6_daddr); 343 } 344 } 345#endif 346 else 347 return NULL; 348 349 net = dev_net(dst->dev); 350 hash = hash_32(hash, net->ipv4.tcp_metrics_hash_log); 351 352 tm = __tcp_get_metrics(&saddr, &daddr, net, hash); 353 if (tm == TCP_METRICS_RECLAIM_PTR) 354 tm = NULL; 355 if (!tm && create) 356 tm = tcpm_new(dst, &saddr, &daddr, hash); 357 else 358 tcpm_check_stamp(tm, dst); 359 360 return tm; 361} 362 363/* Save metrics learned by this TCP session. This function is called 364 * only, when TCP finishes successfully i.e. when it enters TIME-WAIT 365 * or goes from LAST-ACK to CLOSE. 366 */ 367void tcp_update_metrics(struct sock *sk) 368{ 369 const struct inet_connection_sock *icsk = inet_csk(sk); 370 struct dst_entry *dst = __sk_dst_get(sk); 371 struct tcp_sock *tp = tcp_sk(sk); 372 struct tcp_metrics_block *tm; 373 unsigned long rtt; 374 u32 val; 375 int m; 376 377 if (sysctl_tcp_nometrics_save || !dst) 378 return; 379 380 if (dst->flags & DST_HOST) 381 dst_confirm(dst); 382 383 rcu_read_lock(); 384 if (icsk->icsk_backoff || !tp->srtt_us) { 385 /* This session failed to estimate rtt. Why? 386 * Probably, no packets returned in time. Reset our 387 * results. 388 */ 389 tm = tcp_get_metrics(sk, dst, false); 390 if (tm && !tcp_metric_locked(tm, TCP_METRIC_RTT)) 391 tcp_metric_set(tm, TCP_METRIC_RTT, 0); 392 goto out_unlock; 393 } else 394 tm = tcp_get_metrics(sk, dst, true); 395 396 if (!tm) 397 goto out_unlock; 398 399 rtt = tcp_metric_get(tm, TCP_METRIC_RTT); 400 m = rtt - tp->srtt_us; 401 402 /* If newly calculated rtt larger than stored one, store new 403 * one. Otherwise, use EWMA. Remember, rtt overestimation is 404 * always better than underestimation. 405 */ 406 if (!tcp_metric_locked(tm, TCP_METRIC_RTT)) { 407 if (m <= 0) 408 rtt = tp->srtt_us; 409 else 410 rtt -= (m >> 3); 411 tcp_metric_set(tm, TCP_METRIC_RTT, rtt); 412 } 413 414 if (!tcp_metric_locked(tm, TCP_METRIC_RTTVAR)) { 415 unsigned long var; 416 417 if (m < 0) 418 m = -m; 419 420 /* Scale deviation to rttvar fixed point */ 421 m >>= 1; 422 if (m < tp->mdev_us) 423 m = tp->mdev_us; 424 425 var = tcp_metric_get(tm, TCP_METRIC_RTTVAR); 426 if (m >= var) 427 var = m; 428 else 429 var -= (var - m) >> 2; 430 431 tcp_metric_set(tm, TCP_METRIC_RTTVAR, var); 432 } 433 434 if (tcp_in_initial_slowstart(tp)) { 435 /* Slow start still did not finish. */ 436 if (!tcp_metric_locked(tm, TCP_METRIC_SSTHRESH)) { 437 val = tcp_metric_get(tm, TCP_METRIC_SSTHRESH); 438 if (val && (tp->snd_cwnd >> 1) > val) 439 tcp_metric_set(tm, TCP_METRIC_SSTHRESH, 440 tp->snd_cwnd >> 1); 441 } 442 if (!tcp_metric_locked(tm, TCP_METRIC_CWND)) { 443 val = tcp_metric_get(tm, TCP_METRIC_CWND); 444 if (tp->snd_cwnd > val) 445 tcp_metric_set(tm, TCP_METRIC_CWND, 446 tp->snd_cwnd); 447 } 448 } else if (tp->snd_cwnd > tp->snd_ssthresh && 449 icsk->icsk_ca_state == TCP_CA_Open) { 450 /* Cong. avoidance phase, cwnd is reliable. */ 451 if (!tcp_metric_locked(tm, TCP_METRIC_SSTHRESH)) 452 tcp_metric_set(tm, TCP_METRIC_SSTHRESH, 453 max(tp->snd_cwnd >> 1, tp->snd_ssthresh)); 454 if (!tcp_metric_locked(tm, TCP_METRIC_CWND)) { 455 val = tcp_metric_get(tm, TCP_METRIC_CWND); 456 tcp_metric_set(tm, TCP_METRIC_CWND, (val + tp->snd_cwnd) >> 1); 457 } 458 } else { 459 /* Else slow start did not finish, cwnd is non-sense, 460 * ssthresh may be also invalid. 461 */ 462 if (!tcp_metric_locked(tm, TCP_METRIC_CWND)) { 463 val = tcp_metric_get(tm, TCP_METRIC_CWND); 464 tcp_metric_set(tm, TCP_METRIC_CWND, 465 (val + tp->snd_ssthresh) >> 1); 466 } 467 if (!tcp_metric_locked(tm, TCP_METRIC_SSTHRESH)) { 468 val = tcp_metric_get(tm, TCP_METRIC_SSTHRESH); 469 if (val && tp->snd_ssthresh > val) 470 tcp_metric_set(tm, TCP_METRIC_SSTHRESH, 471 tp->snd_ssthresh); 472 } 473 if (!tcp_metric_locked(tm, TCP_METRIC_REORDERING)) { 474 val = tcp_metric_get(tm, TCP_METRIC_REORDERING); 475 if (val < tp->reordering && 476 tp->reordering != sysctl_tcp_reordering) 477 tcp_metric_set(tm, TCP_METRIC_REORDERING, 478 tp->reordering); 479 } 480 } 481 tm->tcpm_stamp = jiffies; 482out_unlock: 483 rcu_read_unlock(); 484} 485 486/* Initialize metrics on socket. */ 487 488void tcp_init_metrics(struct sock *sk) 489{ 490 struct dst_entry *dst = __sk_dst_get(sk); 491 struct tcp_sock *tp = tcp_sk(sk); 492 struct tcp_metrics_block *tm; 493 u32 val, crtt = 0; /* cached RTT scaled by 8 */ 494 495 if (dst == NULL) 496 goto reset; 497 498 dst_confirm(dst); 499 500 rcu_read_lock(); 501 tm = tcp_get_metrics(sk, dst, true); 502 if (!tm) { 503 rcu_read_unlock(); 504 goto reset; 505 } 506 507 if (tcp_metric_locked(tm, TCP_METRIC_CWND)) 508 tp->snd_cwnd_clamp = tcp_metric_get(tm, TCP_METRIC_CWND); 509 510 val = tcp_metric_get(tm, TCP_METRIC_SSTHRESH); 511 if (val) { 512 tp->snd_ssthresh = val; 513 if (tp->snd_ssthresh > tp->snd_cwnd_clamp) 514 tp->snd_ssthresh = tp->snd_cwnd_clamp; 515 } else { 516 /* ssthresh may have been reduced unnecessarily during. 517 * 3WHS. Restore it back to its initial default. 518 */ 519 tp->snd_ssthresh = TCP_INFINITE_SSTHRESH; 520 } 521 val = tcp_metric_get(tm, TCP_METRIC_REORDERING); 522 if (val && tp->reordering != val) { 523 tcp_disable_fack(tp); 524 tcp_disable_early_retrans(tp); 525 tp->reordering = val; 526 } 527 528 crtt = tcp_metric_get(tm, TCP_METRIC_RTT); 529 rcu_read_unlock(); 530reset: 531 /* The initial RTT measurement from the SYN/SYN-ACK is not ideal 532 * to seed the RTO for later data packets because SYN packets are 533 * small. Use the per-dst cached values to seed the RTO but keep 534 * the RTT estimator variables intact (e.g., srtt, mdev, rttvar). 535 * Later the RTO will be updated immediately upon obtaining the first 536 * data RTT sample (tcp_rtt_estimator()). Hence the cached RTT only 537 * influences the first RTO but not later RTT estimation. 538 * 539 * But if RTT is not available from the SYN (due to retransmits or 540 * syn cookies) or the cache, force a conservative 3secs timeout. 541 * 542 * A bit of theory. RTT is time passed after "normal" sized packet 543 * is sent until it is ACKed. In normal circumstances sending small 544 * packets force peer to delay ACKs and calculation is correct too. 545 * The algorithm is adaptive and, provided we follow specs, it 546 * NEVER underestimate RTT. BUT! If peer tries to make some clever 547 * tricks sort of "quick acks" for time long enough to decrease RTT 548 * to low value, and then abruptly stops to do it and starts to delay 549 * ACKs, wait for troubles. 550 */ 551 if (crtt > tp->srtt_us) { 552 /* Set RTO like tcp_rtt_estimator(), but from cached RTT. */ 553 crtt /= 8 * USEC_PER_MSEC; 554 inet_csk(sk)->icsk_rto = crtt + max(2 * crtt, tcp_rto_min(sk)); 555 } else if (tp->srtt_us == 0) { 556 /* RFC6298: 5.7 We've failed to get a valid RTT sample from 557 * 3WHS. This is most likely due to retransmission, 558 * including spurious one. Reset the RTO back to 3secs 559 * from the more aggressive 1sec to avoid more spurious 560 * retransmission. 561 */ 562 tp->rttvar_us = jiffies_to_usecs(TCP_TIMEOUT_FALLBACK); 563 tp->mdev_us = tp->mdev_max_us = tp->rttvar_us; 564 565 inet_csk(sk)->icsk_rto = TCP_TIMEOUT_FALLBACK; 566 } 567 /* Cut cwnd down to 1 per RFC5681 if SYN or SYN-ACK has been 568 * retransmitted. In light of RFC6298 more aggressive 1sec 569 * initRTO, we only reset cwnd when more than 1 SYN/SYN-ACK 570 * retransmission has occurred. 571 */ 572 if (tp->total_retrans > 1) 573 tp->snd_cwnd = 1; 574 else 575 tp->snd_cwnd = tcp_init_cwnd(tp, dst); 576 tp->snd_cwnd_stamp = tcp_time_stamp; 577} 578 579bool tcp_peer_is_proven(struct request_sock *req, struct dst_entry *dst, 580 bool paws_check, bool timestamps) 581{ 582 struct tcp_metrics_block *tm; 583 bool ret; 584 585 if (!dst) 586 return false; 587 588 rcu_read_lock(); 589 tm = __tcp_get_metrics_req(req, dst); 590 if (paws_check) { 591 if (tm && 592 (u32)get_seconds() - tm->tcpm_ts_stamp < TCP_PAWS_MSL && 593 ((s32)(tm->tcpm_ts - req->ts_recent) > TCP_PAWS_WINDOW || 594 !timestamps)) 595 ret = false; 596 else 597 ret = true; 598 } else { 599 if (tm && tcp_metric_get(tm, TCP_METRIC_RTT) && tm->tcpm_ts_stamp) 600 ret = true; 601 else 602 ret = false; 603 } 604 rcu_read_unlock(); 605 606 return ret; 607} 608EXPORT_SYMBOL_GPL(tcp_peer_is_proven); 609 610void tcp_fetch_timewait_stamp(struct sock *sk, struct dst_entry *dst) 611{ 612 struct tcp_metrics_block *tm; 613 614 rcu_read_lock(); 615 tm = tcp_get_metrics(sk, dst, true); 616 if (tm) { 617 struct tcp_sock *tp = tcp_sk(sk); 618 619 if ((u32)get_seconds() - tm->tcpm_ts_stamp <= TCP_PAWS_MSL) { 620 tp->rx_opt.ts_recent_stamp = tm->tcpm_ts_stamp; 621 tp->rx_opt.ts_recent = tm->tcpm_ts; 622 } 623 } 624 rcu_read_unlock(); 625} 626EXPORT_SYMBOL_GPL(tcp_fetch_timewait_stamp); 627 628/* VJ's idea. Save last timestamp seen from this destination and hold 629 * it at least for normal timewait interval to use for duplicate 630 * segment detection in subsequent connections, before they enter 631 * synchronized state. 632 */ 633bool tcp_remember_stamp(struct sock *sk) 634{ 635 struct dst_entry *dst = __sk_dst_get(sk); 636 bool ret = false; 637 638 if (dst) { 639 struct tcp_metrics_block *tm; 640 641 rcu_read_lock(); 642 tm = tcp_get_metrics(sk, dst, true); 643 if (tm) { 644 struct tcp_sock *tp = tcp_sk(sk); 645 646 if ((s32)(tm->tcpm_ts - tp->rx_opt.ts_recent) <= 0 || 647 ((u32)get_seconds() - tm->tcpm_ts_stamp > TCP_PAWS_MSL && 648 tm->tcpm_ts_stamp <= (u32)tp->rx_opt.ts_recent_stamp)) { 649 tm->tcpm_ts_stamp = (u32)tp->rx_opt.ts_recent_stamp; 650 tm->tcpm_ts = tp->rx_opt.ts_recent; 651 } 652 ret = true; 653 } 654 rcu_read_unlock(); 655 } 656 return ret; 657} 658 659bool tcp_tw_remember_stamp(struct inet_timewait_sock *tw) 660{ 661 struct tcp_metrics_block *tm; 662 bool ret = false; 663 664 rcu_read_lock(); 665 tm = __tcp_get_metrics_tw(tw); 666 if (tm) { 667 const struct tcp_timewait_sock *tcptw; 668 struct sock *sk = (struct sock *) tw; 669 670 tcptw = tcp_twsk(sk); 671 if ((s32)(tm->tcpm_ts - tcptw->tw_ts_recent) <= 0 || 672 ((u32)get_seconds() - tm->tcpm_ts_stamp > TCP_PAWS_MSL && 673 tm->tcpm_ts_stamp <= (u32)tcptw->tw_ts_recent_stamp)) { 674 tm->tcpm_ts_stamp = (u32)tcptw->tw_ts_recent_stamp; 675 tm->tcpm_ts = tcptw->tw_ts_recent; 676 } 677 ret = true; 678 } 679 rcu_read_unlock(); 680 681 return ret; 682} 683 684static DEFINE_SEQLOCK(fastopen_seqlock); 685 686void tcp_fastopen_cache_get(struct sock *sk, u16 *mss, 687 struct tcp_fastopen_cookie *cookie, 688 int *syn_loss, unsigned long *last_syn_loss) 689{ 690 struct tcp_metrics_block *tm; 691 692 rcu_read_lock(); 693 tm = tcp_get_metrics(sk, __sk_dst_get(sk), false); 694 if (tm) { 695 struct tcp_fastopen_metrics *tfom = &tm->tcpm_fastopen; 696 unsigned int seq; 697 698 do { 699 seq = read_seqbegin(&fastopen_seqlock); 700 if (tfom->mss) 701 *mss = tfom->mss; 702 *cookie = tfom->cookie; 703 *syn_loss = tfom->syn_loss; 704 *last_syn_loss = *syn_loss ? tfom->last_syn_loss : 0; 705 } while (read_seqretry(&fastopen_seqlock, seq)); 706 } 707 rcu_read_unlock(); 708} 709 710void tcp_fastopen_cache_set(struct sock *sk, u16 mss, 711 struct tcp_fastopen_cookie *cookie, bool syn_lost) 712{ 713 struct dst_entry *dst = __sk_dst_get(sk); 714 struct tcp_metrics_block *tm; 715 716 if (!dst) 717 return; 718 rcu_read_lock(); 719 tm = tcp_get_metrics(sk, dst, true); 720 if (tm) { 721 struct tcp_fastopen_metrics *tfom = &tm->tcpm_fastopen; 722 723 write_seqlock_bh(&fastopen_seqlock); 724 if (mss) 725 tfom->mss = mss; 726 if (cookie && cookie->len > 0) 727 tfom->cookie = *cookie; 728 if (syn_lost) { 729 ++tfom->syn_loss; 730 tfom->last_syn_loss = jiffies; 731 } else 732 tfom->syn_loss = 0; 733 write_sequnlock_bh(&fastopen_seqlock); 734 } 735 rcu_read_unlock(); 736} 737 738static struct genl_family tcp_metrics_nl_family = { 739 .id = GENL_ID_GENERATE, 740 .hdrsize = 0, 741 .name = TCP_METRICS_GENL_NAME, 742 .version = TCP_METRICS_GENL_VERSION, 743 .maxattr = TCP_METRICS_ATTR_MAX, 744 .netnsok = true, 745}; 746 747static struct nla_policy tcp_metrics_nl_policy[TCP_METRICS_ATTR_MAX + 1] = { 748 [TCP_METRICS_ATTR_ADDR_IPV4] = { .type = NLA_U32, }, 749 [TCP_METRICS_ATTR_ADDR_IPV6] = { .type = NLA_BINARY, 750 .len = sizeof(struct in6_addr), }, 751 /* Following attributes are not received for GET/DEL, 752 * we keep them for reference 753 */ 754#if 0 755 [TCP_METRICS_ATTR_AGE] = { .type = NLA_MSECS, }, 756 [TCP_METRICS_ATTR_TW_TSVAL] = { .type = NLA_U32, }, 757 [TCP_METRICS_ATTR_TW_TS_STAMP] = { .type = NLA_S32, }, 758 [TCP_METRICS_ATTR_VALS] = { .type = NLA_NESTED, }, 759 [TCP_METRICS_ATTR_FOPEN_MSS] = { .type = NLA_U16, }, 760 [TCP_METRICS_ATTR_FOPEN_SYN_DROPS] = { .type = NLA_U16, }, 761 [TCP_METRICS_ATTR_FOPEN_SYN_DROP_TS] = { .type = NLA_MSECS, }, 762 [TCP_METRICS_ATTR_FOPEN_COOKIE] = { .type = NLA_BINARY, 763 .len = TCP_FASTOPEN_COOKIE_MAX, }, 764#endif 765}; 766 767/* Add attributes, caller cancels its header on failure */ 768static int tcp_metrics_fill_info(struct sk_buff *msg, 769 struct tcp_metrics_block *tm) 770{ 771 struct nlattr *nest; 772 int i; 773 774 switch (tm->tcpm_daddr.family) { 775 case AF_INET: 776 if (nla_put_be32(msg, TCP_METRICS_ATTR_ADDR_IPV4, 777 tm->tcpm_daddr.addr.a4) < 0) 778 goto nla_put_failure; 779 if (nla_put_be32(msg, TCP_METRICS_ATTR_SADDR_IPV4, 780 tm->tcpm_saddr.addr.a4) < 0) 781 goto nla_put_failure; 782 break; 783 case AF_INET6: 784 if (nla_put(msg, TCP_METRICS_ATTR_ADDR_IPV6, 16, 785 tm->tcpm_daddr.addr.a6) < 0) 786 goto nla_put_failure; 787 if (nla_put(msg, TCP_METRICS_ATTR_SADDR_IPV6, 16, 788 tm->tcpm_saddr.addr.a6) < 0) 789 goto nla_put_failure; 790 break; 791 default: 792 return -EAFNOSUPPORT; 793 } 794 795 if (nla_put_msecs(msg, TCP_METRICS_ATTR_AGE, 796 jiffies - tm->tcpm_stamp) < 0) 797 goto nla_put_failure; 798 if (tm->tcpm_ts_stamp) { 799 if (nla_put_s32(msg, TCP_METRICS_ATTR_TW_TS_STAMP, 800 (s32) (get_seconds() - tm->tcpm_ts_stamp)) < 0) 801 goto nla_put_failure; 802 if (nla_put_u32(msg, TCP_METRICS_ATTR_TW_TSVAL, 803 tm->tcpm_ts) < 0) 804 goto nla_put_failure; 805 } 806 807 { 808 int n = 0; 809 810 nest = nla_nest_start(msg, TCP_METRICS_ATTR_VALS); 811 if (!nest) 812 goto nla_put_failure; 813 for (i = 0; i < TCP_METRIC_MAX_KERNEL + 1; i++) { 814 u32 val = tm->tcpm_vals[i]; 815 816 if (!val) 817 continue; 818 if (i == TCP_METRIC_RTT) { 819 if (nla_put_u32(msg, TCP_METRIC_RTT_US + 1, 820 val) < 0) 821 goto nla_put_failure; 822 n++; 823 val = max(val / 1000, 1U); 824 } 825 if (i == TCP_METRIC_RTTVAR) { 826 if (nla_put_u32(msg, TCP_METRIC_RTTVAR_US + 1, 827 val) < 0) 828 goto nla_put_failure; 829 n++; 830 val = max(val / 1000, 1U); 831 } 832 if (nla_put_u32(msg, i + 1, val) < 0) 833 goto nla_put_failure; 834 n++; 835 } 836 if (n) 837 nla_nest_end(msg, nest); 838 else 839 nla_nest_cancel(msg, nest); 840 } 841 842 { 843 struct tcp_fastopen_metrics tfom_copy[1], *tfom; 844 unsigned int seq; 845 846 do { 847 seq = read_seqbegin(&fastopen_seqlock); 848 tfom_copy[0] = tm->tcpm_fastopen; 849 } while (read_seqretry(&fastopen_seqlock, seq)); 850 851 tfom = tfom_copy; 852 if (tfom->mss && 853 nla_put_u16(msg, TCP_METRICS_ATTR_FOPEN_MSS, 854 tfom->mss) < 0) 855 goto nla_put_failure; 856 if (tfom->syn_loss && 857 (nla_put_u16(msg, TCP_METRICS_ATTR_FOPEN_SYN_DROPS, 858 tfom->syn_loss) < 0 || 859 nla_put_msecs(msg, TCP_METRICS_ATTR_FOPEN_SYN_DROP_TS, 860 jiffies - tfom->last_syn_loss) < 0)) 861 goto nla_put_failure; 862 if (tfom->cookie.len > 0 && 863 nla_put(msg, TCP_METRICS_ATTR_FOPEN_COOKIE, 864 tfom->cookie.len, tfom->cookie.val) < 0) 865 goto nla_put_failure; 866 } 867 868 return 0; 869 870nla_put_failure: 871 return -EMSGSIZE; 872} 873 874static int tcp_metrics_dump_info(struct sk_buff *skb, 875 struct netlink_callback *cb, 876 struct tcp_metrics_block *tm) 877{ 878 void *hdr; 879 880 hdr = genlmsg_put(skb, NETLINK_CB(cb->skb).portid, cb->nlh->nlmsg_seq, 881 &tcp_metrics_nl_family, NLM_F_MULTI, 882 TCP_METRICS_CMD_GET); 883 if (!hdr) 884 return -EMSGSIZE; 885 886 if (tcp_metrics_fill_info(skb, tm) < 0) 887 goto nla_put_failure; 888 889 return genlmsg_end(skb, hdr); 890 891nla_put_failure: 892 genlmsg_cancel(skb, hdr); 893 return -EMSGSIZE; 894} 895 896static int tcp_metrics_nl_dump(struct sk_buff *skb, 897 struct netlink_callback *cb) 898{ 899 struct net *net = sock_net(skb->sk); 900 unsigned int max_rows = 1U << net->ipv4.tcp_metrics_hash_log; 901 unsigned int row, s_row = cb->args[0]; 902 int s_col = cb->args[1], col = s_col; 903 904 for (row = s_row; row < max_rows; row++, s_col = 0) { 905 struct tcp_metrics_block *tm; 906 struct tcpm_hash_bucket *hb = net->ipv4.tcp_metrics_hash + row; 907 908 rcu_read_lock(); 909 for (col = 0, tm = rcu_dereference(hb->chain); tm; 910 tm = rcu_dereference(tm->tcpm_next), col++) { 911 if (col < s_col) 912 continue; 913 if (tcp_metrics_dump_info(skb, cb, tm) < 0) { 914 rcu_read_unlock(); 915 goto done; 916 } 917 } 918 rcu_read_unlock(); 919 } 920 921done: 922 cb->args[0] = row; 923 cb->args[1] = col; 924 return skb->len; 925} 926 927static int __parse_nl_addr(struct genl_info *info, struct inetpeer_addr *addr, 928 unsigned int *hash, int optional, int v4, int v6) 929{ 930 struct nlattr *a; 931 932 a = info->attrs[v4]; 933 if (a) { 934 addr->family = AF_INET; 935 addr->addr.a4 = nla_get_be32(a); 936 if (hash) 937 *hash = (__force unsigned int) addr->addr.a4; 938 return 0; 939 } 940 a = info->attrs[v6]; 941 if (a) { 942 if (nla_len(a) != sizeof(struct in6_addr)) 943 return -EINVAL; 944 addr->family = AF_INET6; 945 memcpy(addr->addr.a6, nla_data(a), sizeof(addr->addr.a6)); 946 if (hash) 947 *hash = ipv6_addr_hash((struct in6_addr *) addr->addr.a6); 948 return 0; 949 } 950 return optional ? 1 : -EAFNOSUPPORT; 951} 952 953static int parse_nl_addr(struct genl_info *info, struct inetpeer_addr *addr, 954 unsigned int *hash, int optional) 955{ 956 return __parse_nl_addr(info, addr, hash, optional, 957 TCP_METRICS_ATTR_ADDR_IPV4, 958 TCP_METRICS_ATTR_ADDR_IPV6); 959} 960 961static int parse_nl_saddr(struct genl_info *info, struct inetpeer_addr *addr) 962{ 963 return __parse_nl_addr(info, addr, NULL, 0, 964 TCP_METRICS_ATTR_SADDR_IPV4, 965 TCP_METRICS_ATTR_SADDR_IPV6); 966} 967 968static int tcp_metrics_nl_cmd_get(struct sk_buff *skb, struct genl_info *info) 969{ 970 struct tcp_metrics_block *tm; 971 struct inetpeer_addr saddr, daddr; 972 unsigned int hash; 973 struct sk_buff *msg; 974 struct net *net = genl_info_net(info); 975 void *reply; 976 int ret; 977 bool src = true; 978 979 ret = parse_nl_addr(info, &daddr, &hash, 0); 980 if (ret < 0) 981 return ret; 982 983 ret = parse_nl_saddr(info, &saddr); 984 if (ret < 0) 985 src = false; 986 987 msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL); 988 if (!msg) 989 return -ENOMEM; 990 991 reply = genlmsg_put_reply(msg, info, &tcp_metrics_nl_family, 0, 992 info->genlhdr->cmd); 993 if (!reply) 994 goto nla_put_failure; 995 996 hash = hash_32(hash, net->ipv4.tcp_metrics_hash_log); 997 ret = -ESRCH; 998 rcu_read_lock(); 999 for (tm = rcu_dereference(net->ipv4.tcp_metrics_hash[hash].chain); tm; 1000 tm = rcu_dereference(tm->tcpm_next)) { 1001 if (addr_same(&tm->tcpm_daddr, &daddr) && 1002 (!src || addr_same(&tm->tcpm_saddr, &saddr))) { 1003 ret = tcp_metrics_fill_info(msg, tm); 1004 break; 1005 } 1006 } 1007 rcu_read_unlock(); 1008 if (ret < 0) 1009 goto out_free; 1010 1011 genlmsg_end(msg, reply); 1012 return genlmsg_reply(msg, info); 1013 1014nla_put_failure: 1015 ret = -EMSGSIZE; 1016 1017out_free: 1018 nlmsg_free(msg); 1019 return ret; 1020} 1021 1022#define deref_locked_genl(p) \ 1023 rcu_dereference_protected(p, lockdep_genl_is_held() && \ 1024 lockdep_is_held(&tcp_metrics_lock)) 1025 1026#define deref_genl(p) rcu_dereference_protected(p, lockdep_genl_is_held()) 1027 1028static int tcp_metrics_flush_all(struct net *net) 1029{ 1030 unsigned int max_rows = 1U << net->ipv4.tcp_metrics_hash_log; 1031 struct tcpm_hash_bucket *hb = net->ipv4.tcp_metrics_hash; 1032 struct tcp_metrics_block *tm; 1033 unsigned int row; 1034 1035 for (row = 0; row < max_rows; row++, hb++) { 1036 spin_lock_bh(&tcp_metrics_lock); 1037 tm = deref_locked_genl(hb->chain); 1038 if (tm) 1039 hb->chain = NULL; 1040 spin_unlock_bh(&tcp_metrics_lock); 1041 while (tm) { 1042 struct tcp_metrics_block *next; 1043 1044 next = deref_genl(tm->tcpm_next); 1045 kfree_rcu(tm, rcu_head); 1046 tm = next; 1047 } 1048 } 1049 return 0; 1050} 1051 1052static int tcp_metrics_nl_cmd_del(struct sk_buff *skb, struct genl_info *info) 1053{ 1054 struct tcpm_hash_bucket *hb; 1055 struct tcp_metrics_block *tm; 1056 struct tcp_metrics_block __rcu **pp; 1057 struct inetpeer_addr saddr, daddr; 1058 unsigned int hash; 1059 struct net *net = genl_info_net(info); 1060 int ret; 1061 bool src = true, found = false; 1062 1063 ret = parse_nl_addr(info, &daddr, &hash, 1); 1064 if (ret < 0) 1065 return ret; 1066 if (ret > 0) 1067 return tcp_metrics_flush_all(net); 1068 ret = parse_nl_saddr(info, &saddr); 1069 if (ret < 0) 1070 src = false; 1071 1072 hash = hash_32(hash, net->ipv4.tcp_metrics_hash_log); 1073 hb = net->ipv4.tcp_metrics_hash + hash; 1074 pp = &hb->chain; 1075 spin_lock_bh(&tcp_metrics_lock); 1076 for (tm = deref_locked_genl(*pp); tm; tm = deref_locked_genl(*pp)) { 1077 if (addr_same(&tm->tcpm_daddr, &daddr) && 1078 (!src || addr_same(&tm->tcpm_saddr, &saddr))) { 1079 *pp = tm->tcpm_next; 1080 kfree_rcu(tm, rcu_head); 1081 found = true; 1082 } else { 1083 pp = &tm->tcpm_next; 1084 } 1085 } 1086 spin_unlock_bh(&tcp_metrics_lock); 1087 if (!found) 1088 return -ESRCH; 1089 return 0; 1090} 1091 1092static const struct genl_ops tcp_metrics_nl_ops[] = { 1093 { 1094 .cmd = TCP_METRICS_CMD_GET, 1095 .doit = tcp_metrics_nl_cmd_get, 1096 .dumpit = tcp_metrics_nl_dump, 1097 .policy = tcp_metrics_nl_policy, 1098 }, 1099 { 1100 .cmd = TCP_METRICS_CMD_DEL, 1101 .doit = tcp_metrics_nl_cmd_del, 1102 .policy = tcp_metrics_nl_policy, 1103 .flags = GENL_ADMIN_PERM, 1104 }, 1105}; 1106 1107static unsigned int tcpmhash_entries; 1108static int __init set_tcpmhash_entries(char *str) 1109{ 1110 ssize_t ret; 1111 1112 if (!str) 1113 return 0; 1114 1115 ret = kstrtouint(str, 0, &tcpmhash_entries); 1116 if (ret) 1117 return 0; 1118 1119 return 1; 1120} 1121__setup("tcpmhash_entries=", set_tcpmhash_entries); 1122 1123static int __net_init tcp_net_metrics_init(struct net *net) 1124{ 1125 size_t size; 1126 unsigned int slots; 1127 1128 slots = tcpmhash_entries; 1129 if (!slots) { 1130 if (totalram_pages >= 128 * 1024) 1131 slots = 16 * 1024; 1132 else 1133 slots = 8 * 1024; 1134 } 1135 1136 net->ipv4.tcp_metrics_hash_log = order_base_2(slots); 1137 size = sizeof(struct tcpm_hash_bucket) << net->ipv4.tcp_metrics_hash_log; 1138 1139 net->ipv4.tcp_metrics_hash = kzalloc(size, GFP_KERNEL | __GFP_NOWARN); 1140 if (!net->ipv4.tcp_metrics_hash) 1141 net->ipv4.tcp_metrics_hash = vzalloc(size); 1142 1143 if (!net->ipv4.tcp_metrics_hash) 1144 return -ENOMEM; 1145 1146 return 0; 1147} 1148 1149static void __net_exit tcp_net_metrics_exit(struct net *net) 1150{ 1151 unsigned int i; 1152 1153 for (i = 0; i < (1U << net->ipv4.tcp_metrics_hash_log) ; i++) { 1154 struct tcp_metrics_block *tm, *next; 1155 1156 tm = rcu_dereference_protected(net->ipv4.tcp_metrics_hash[i].chain, 1); 1157 while (tm) { 1158 next = rcu_dereference_protected(tm->tcpm_next, 1); 1159 kfree(tm); 1160 tm = next; 1161 } 1162 } 1163 kvfree(net->ipv4.tcp_metrics_hash); 1164} 1165 1166static __net_initdata struct pernet_operations tcp_net_metrics_ops = { 1167 .init = tcp_net_metrics_init, 1168 .exit = tcp_net_metrics_exit, 1169}; 1170 1171void __init tcp_metrics_init(void) 1172{ 1173 int ret; 1174 1175 ret = register_pernet_subsys(&tcp_net_metrics_ops); 1176 if (ret < 0) 1177 goto cleanup; 1178 ret = genl_register_family_with_ops(&tcp_metrics_nl_family, 1179 tcp_metrics_nl_ops); 1180 if (ret < 0) 1181 goto cleanup_subsys; 1182 return; 1183 1184cleanup_subsys: 1185 unregister_pernet_subsys(&tcp_net_metrics_ops); 1186 1187cleanup: 1188 return; 1189} 1190