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