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 static 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 29 struct tcp_fastopen_metrics { 30 u16 mss; 31 u16 syn_loss:10, /* Recurring Fast Open SYN losses */ 32 try_exp:2; /* Request w/ exp. option (once) */ 33 unsigned long last_syn_loss; /* Last Fast Open SYN loss */ 34 struct tcp_fastopen_cookie cookie; 35 }; 36 37 /* TCP_METRIC_MAX includes 2 extra fields for userspace compatibility 38 * Kernel only stores RTT and RTTVAR in usec resolution 39 */ 40 #define TCP_METRIC_MAX_KERNEL (TCP_METRIC_MAX - 2) 41 42 struct tcp_metrics_block { 43 struct tcp_metrics_block __rcu *tcpm_next; 44 possible_net_t tcpm_net; 45 struct inetpeer_addr tcpm_saddr; 46 struct inetpeer_addr tcpm_daddr; 47 unsigned long tcpm_stamp; 48 u32 tcpm_ts; 49 u32 tcpm_ts_stamp; 50 u32 tcpm_lock; 51 u32 tcpm_vals[TCP_METRIC_MAX_KERNEL + 1]; 52 struct tcp_fastopen_metrics tcpm_fastopen; 53 54 struct rcu_head rcu_head; 55 }; 56 57 static inline struct net *tm_net(struct tcp_metrics_block *tm) 58 { 59 return read_pnet(&tm->tcpm_net); 60 } 61 62 static bool tcp_metric_locked(struct tcp_metrics_block *tm, 63 enum tcp_metric_index idx) 64 { 65 return tm->tcpm_lock & (1 << idx); 66 } 67 68 static u32 tcp_metric_get(struct tcp_metrics_block *tm, 69 enum tcp_metric_index idx) 70 { 71 return tm->tcpm_vals[idx]; 72 } 73 74 static void tcp_metric_set(struct tcp_metrics_block *tm, 75 enum tcp_metric_index idx, 76 u32 val) 77 { 78 tm->tcpm_vals[idx] = val; 79 } 80 81 static bool addr_same(const struct inetpeer_addr *a, 82 const struct inetpeer_addr *b) 83 { 84 if (a->family != b->family) 85 return false; 86 if (a->family == AF_INET) 87 return a->addr.a4 == b->addr.a4; 88 return ipv6_addr_equal(&a->addr.in6, &b->addr.in6); 89 } 90 91 struct tcpm_hash_bucket { 92 struct tcp_metrics_block __rcu *chain; 93 }; 94 95 static struct tcpm_hash_bucket *tcp_metrics_hash __read_mostly; 96 static unsigned int tcp_metrics_hash_log __read_mostly; 97 98 static DEFINE_SPINLOCK(tcp_metrics_lock); 99 100 static void tcpm_suck_dst(struct tcp_metrics_block *tm, 101 const struct dst_entry *dst, 102 bool fastopen_clear) 103 { 104 u32 msval; 105 u32 val; 106 107 tm->tcpm_stamp = jiffies; 108 109 val = 0; 110 if (dst_metric_locked(dst, RTAX_RTT)) 111 val |= 1 << TCP_METRIC_RTT; 112 if (dst_metric_locked(dst, RTAX_RTTVAR)) 113 val |= 1 << TCP_METRIC_RTTVAR; 114 if (dst_metric_locked(dst, RTAX_SSTHRESH)) 115 val |= 1 << TCP_METRIC_SSTHRESH; 116 if (dst_metric_locked(dst, RTAX_CWND)) 117 val |= 1 << TCP_METRIC_CWND; 118 if (dst_metric_locked(dst, RTAX_REORDERING)) 119 val |= 1 << TCP_METRIC_REORDERING; 120 tm->tcpm_lock = val; 121 122 msval = dst_metric_raw(dst, RTAX_RTT); 123 tm->tcpm_vals[TCP_METRIC_RTT] = msval * USEC_PER_MSEC; 124 125 msval = dst_metric_raw(dst, RTAX_RTTVAR); 126 tm->tcpm_vals[TCP_METRIC_RTTVAR] = msval * USEC_PER_MSEC; 127 tm->tcpm_vals[TCP_METRIC_SSTHRESH] = dst_metric_raw(dst, RTAX_SSTHRESH); 128 tm->tcpm_vals[TCP_METRIC_CWND] = dst_metric_raw(dst, RTAX_CWND); 129 tm->tcpm_vals[TCP_METRIC_REORDERING] = dst_metric_raw(dst, RTAX_REORDERING); 130 tm->tcpm_ts = 0; 131 tm->tcpm_ts_stamp = 0; 132 if (fastopen_clear) { 133 tm->tcpm_fastopen.mss = 0; 134 tm->tcpm_fastopen.syn_loss = 0; 135 tm->tcpm_fastopen.try_exp = 0; 136 tm->tcpm_fastopen.cookie.exp = false; 137 tm->tcpm_fastopen.cookie.len = 0; 138 } 139 } 140 141 #define TCP_METRICS_TIMEOUT (60 * 60 * HZ) 142 143 static void tcpm_check_stamp(struct tcp_metrics_block *tm, struct dst_entry *dst) 144 { 145 if (tm && unlikely(time_after(jiffies, tm->tcpm_stamp + TCP_METRICS_TIMEOUT))) 146 tcpm_suck_dst(tm, dst, false); 147 } 148 149 #define TCP_METRICS_RECLAIM_DEPTH 5 150 #define TCP_METRICS_RECLAIM_PTR (struct tcp_metrics_block *) 0x1UL 151 152 #define deref_locked(p) \ 153 rcu_dereference_protected(p, lockdep_is_held(&tcp_metrics_lock)) 154 155 static struct tcp_metrics_block *tcpm_new(struct dst_entry *dst, 156 struct inetpeer_addr *saddr, 157 struct inetpeer_addr *daddr, 158 unsigned int hash) 159 { 160 struct tcp_metrics_block *tm; 161 struct net *net; 162 bool reclaim = false; 163 164 spin_lock_bh(&tcp_metrics_lock); 165 net = dev_net(dst->dev); 166 167 /* While waiting for the spin-lock the cache might have been populated 168 * with this entry and so we have to check again. 169 */ 170 tm = __tcp_get_metrics(saddr, daddr, net, hash); 171 if (tm == TCP_METRICS_RECLAIM_PTR) { 172 reclaim = true; 173 tm = NULL; 174 } 175 if (tm) { 176 tcpm_check_stamp(tm, dst); 177 goto out_unlock; 178 } 179 180 if (unlikely(reclaim)) { 181 struct tcp_metrics_block *oldest; 182 183 oldest = deref_locked(tcp_metrics_hash[hash].chain); 184 for (tm = deref_locked(oldest->tcpm_next); tm; 185 tm = deref_locked(tm->tcpm_next)) { 186 if (time_before(tm->tcpm_stamp, oldest->tcpm_stamp)) 187 oldest = tm; 188 } 189 tm = oldest; 190 } else { 191 tm = kmalloc(sizeof(*tm), GFP_ATOMIC); 192 if (!tm) 193 goto out_unlock; 194 } 195 write_pnet(&tm->tcpm_net, net); 196 tm->tcpm_saddr = *saddr; 197 tm->tcpm_daddr = *daddr; 198 199 tcpm_suck_dst(tm, dst, true); 200 201 if (likely(!reclaim)) { 202 tm->tcpm_next = tcp_metrics_hash[hash].chain; 203 rcu_assign_pointer(tcp_metrics_hash[hash].chain, tm); 204 } 205 206 out_unlock: 207 spin_unlock_bh(&tcp_metrics_lock); 208 return tm; 209 } 210 211 static struct tcp_metrics_block *tcp_get_encode(struct tcp_metrics_block *tm, int depth) 212 { 213 if (tm) 214 return tm; 215 if (depth > TCP_METRICS_RECLAIM_DEPTH) 216 return TCP_METRICS_RECLAIM_PTR; 217 return NULL; 218 } 219 220 static struct tcp_metrics_block *__tcp_get_metrics(const struct inetpeer_addr *saddr, 221 const struct inetpeer_addr *daddr, 222 struct net *net, unsigned int hash) 223 { 224 struct tcp_metrics_block *tm; 225 int depth = 0; 226 227 for (tm = rcu_dereference(tcp_metrics_hash[hash].chain); tm; 228 tm = rcu_dereference(tm->tcpm_next)) { 229 if (addr_same(&tm->tcpm_saddr, saddr) && 230 addr_same(&tm->tcpm_daddr, daddr) && 231 net_eq(tm_net(tm), net)) 232 break; 233 depth++; 234 } 235 return tcp_get_encode(tm, depth); 236 } 237 238 static struct tcp_metrics_block *__tcp_get_metrics_req(struct request_sock *req, 239 struct dst_entry *dst) 240 { 241 struct tcp_metrics_block *tm; 242 struct inetpeer_addr saddr, daddr; 243 unsigned int hash; 244 struct net *net; 245 246 saddr.family = req->rsk_ops->family; 247 daddr.family = req->rsk_ops->family; 248 switch (daddr.family) { 249 case AF_INET: 250 saddr.addr.a4 = inet_rsk(req)->ir_loc_addr; 251 daddr.addr.a4 = inet_rsk(req)->ir_rmt_addr; 252 hash = (__force unsigned int) daddr.addr.a4; 253 break; 254 #if IS_ENABLED(CONFIG_IPV6) 255 case AF_INET6: 256 saddr.addr.in6 = inet_rsk(req)->ir_v6_loc_addr; 257 daddr.addr.in6 = inet_rsk(req)->ir_v6_rmt_addr; 258 hash = ipv6_addr_hash(&inet_rsk(req)->ir_v6_rmt_addr); 259 break; 260 #endif 261 default: 262 return NULL; 263 } 264 265 net = dev_net(dst->dev); 266 hash ^= net_hash_mix(net); 267 hash = hash_32(hash, tcp_metrics_hash_log); 268 269 for (tm = rcu_dereference(tcp_metrics_hash[hash].chain); tm; 270 tm = rcu_dereference(tm->tcpm_next)) { 271 if (addr_same(&tm->tcpm_saddr, &saddr) && 272 addr_same(&tm->tcpm_daddr, &daddr) && 273 net_eq(tm_net(tm), net)) 274 break; 275 } 276 tcpm_check_stamp(tm, dst); 277 return tm; 278 } 279 280 static struct tcp_metrics_block *__tcp_get_metrics_tw(struct inet_timewait_sock *tw) 281 { 282 struct tcp_metrics_block *tm; 283 struct inetpeer_addr saddr, daddr; 284 unsigned int hash; 285 struct net *net; 286 287 if (tw->tw_family == AF_INET) { 288 saddr.family = AF_INET; 289 saddr.addr.a4 = tw->tw_rcv_saddr; 290 daddr.family = AF_INET; 291 daddr.addr.a4 = tw->tw_daddr; 292 hash = (__force unsigned int) daddr.addr.a4; 293 } 294 #if IS_ENABLED(CONFIG_IPV6) 295 else if (tw->tw_family == AF_INET6) { 296 if (ipv6_addr_v4mapped(&tw->tw_v6_daddr)) { 297 saddr.family = AF_INET; 298 saddr.addr.a4 = tw->tw_rcv_saddr; 299 daddr.family = AF_INET; 300 daddr.addr.a4 = tw->tw_daddr; 301 hash = (__force unsigned int) daddr.addr.a4; 302 } else { 303 saddr.family = AF_INET6; 304 saddr.addr.in6 = tw->tw_v6_rcv_saddr; 305 daddr.family = AF_INET6; 306 daddr.addr.in6 = tw->tw_v6_daddr; 307 hash = ipv6_addr_hash(&tw->tw_v6_daddr); 308 } 309 } 310 #endif 311 else 312 return NULL; 313 314 net = twsk_net(tw); 315 hash ^= net_hash_mix(net); 316 hash = hash_32(hash, tcp_metrics_hash_log); 317 318 for (tm = rcu_dereference(tcp_metrics_hash[hash].chain); tm; 319 tm = rcu_dereference(tm->tcpm_next)) { 320 if (addr_same(&tm->tcpm_saddr, &saddr) && 321 addr_same(&tm->tcpm_daddr, &daddr) && 322 net_eq(tm_net(tm), net)) 323 break; 324 } 325 return tm; 326 } 327 328 static struct tcp_metrics_block *tcp_get_metrics(struct sock *sk, 329 struct dst_entry *dst, 330 bool create) 331 { 332 struct tcp_metrics_block *tm; 333 struct inetpeer_addr saddr, daddr; 334 unsigned int hash; 335 struct net *net; 336 337 if (sk->sk_family == AF_INET) { 338 saddr.family = AF_INET; 339 saddr.addr.a4 = inet_sk(sk)->inet_saddr; 340 daddr.family = AF_INET; 341 daddr.addr.a4 = inet_sk(sk)->inet_daddr; 342 hash = (__force unsigned int) daddr.addr.a4; 343 } 344 #if IS_ENABLED(CONFIG_IPV6) 345 else if (sk->sk_family == AF_INET6) { 346 if (ipv6_addr_v4mapped(&sk->sk_v6_daddr)) { 347 saddr.family = AF_INET; 348 saddr.addr.a4 = inet_sk(sk)->inet_saddr; 349 daddr.family = AF_INET; 350 daddr.addr.a4 = inet_sk(sk)->inet_daddr; 351 hash = (__force unsigned int) daddr.addr.a4; 352 } else { 353 saddr.family = AF_INET6; 354 saddr.addr.in6 = sk->sk_v6_rcv_saddr; 355 daddr.family = AF_INET6; 356 daddr.addr.in6 = sk->sk_v6_daddr; 357 hash = ipv6_addr_hash(&sk->sk_v6_daddr); 358 } 359 } 360 #endif 361 else 362 return NULL; 363 364 net = dev_net(dst->dev); 365 hash ^= net_hash_mix(net); 366 hash = hash_32(hash, tcp_metrics_hash_log); 367 368 tm = __tcp_get_metrics(&saddr, &daddr, net, hash); 369 if (tm == TCP_METRICS_RECLAIM_PTR) 370 tm = NULL; 371 if (!tm && create) 372 tm = tcpm_new(dst, &saddr, &daddr, hash); 373 else 374 tcpm_check_stamp(tm, dst); 375 376 return tm; 377 } 378 379 /* Save metrics learned by this TCP session. This function is called 380 * only, when TCP finishes successfully i.e. when it enters TIME-WAIT 381 * or goes from LAST-ACK to CLOSE. 382 */ 383 void tcp_update_metrics(struct sock *sk) 384 { 385 const struct inet_connection_sock *icsk = inet_csk(sk); 386 struct dst_entry *dst = __sk_dst_get(sk); 387 struct tcp_sock *tp = tcp_sk(sk); 388 struct tcp_metrics_block *tm; 389 unsigned long rtt; 390 u32 val; 391 int m; 392 393 if (sysctl_tcp_nometrics_save || !dst) 394 return; 395 396 if (dst->flags & DST_HOST) 397 dst_confirm(dst); 398 399 rcu_read_lock(); 400 if (icsk->icsk_backoff || !tp->srtt_us) { 401 /* This session failed to estimate rtt. Why? 402 * Probably, no packets returned in time. Reset our 403 * results. 404 */ 405 tm = tcp_get_metrics(sk, dst, false); 406 if (tm && !tcp_metric_locked(tm, TCP_METRIC_RTT)) 407 tcp_metric_set(tm, TCP_METRIC_RTT, 0); 408 goto out_unlock; 409 } else 410 tm = tcp_get_metrics(sk, dst, true); 411 412 if (!tm) 413 goto out_unlock; 414 415 rtt = tcp_metric_get(tm, TCP_METRIC_RTT); 416 m = rtt - tp->srtt_us; 417 418 /* If newly calculated rtt larger than stored one, store new 419 * one. Otherwise, use EWMA. Remember, rtt overestimation is 420 * always better than underestimation. 421 */ 422 if (!tcp_metric_locked(tm, TCP_METRIC_RTT)) { 423 if (m <= 0) 424 rtt = tp->srtt_us; 425 else 426 rtt -= (m >> 3); 427 tcp_metric_set(tm, TCP_METRIC_RTT, rtt); 428 } 429 430 if (!tcp_metric_locked(tm, TCP_METRIC_RTTVAR)) { 431 unsigned long var; 432 433 if (m < 0) 434 m = -m; 435 436 /* Scale deviation to rttvar fixed point */ 437 m >>= 1; 438 if (m < tp->mdev_us) 439 m = tp->mdev_us; 440 441 var = tcp_metric_get(tm, TCP_METRIC_RTTVAR); 442 if (m >= var) 443 var = m; 444 else 445 var -= (var - m) >> 2; 446 447 tcp_metric_set(tm, TCP_METRIC_RTTVAR, var); 448 } 449 450 if (tcp_in_initial_slowstart(tp)) { 451 /* Slow start still did not finish. */ 452 if (!tcp_metric_locked(tm, TCP_METRIC_SSTHRESH)) { 453 val = tcp_metric_get(tm, TCP_METRIC_SSTHRESH); 454 if (val && (tp->snd_cwnd >> 1) > val) 455 tcp_metric_set(tm, TCP_METRIC_SSTHRESH, 456 tp->snd_cwnd >> 1); 457 } 458 if (!tcp_metric_locked(tm, TCP_METRIC_CWND)) { 459 val = tcp_metric_get(tm, TCP_METRIC_CWND); 460 if (tp->snd_cwnd > val) 461 tcp_metric_set(tm, TCP_METRIC_CWND, 462 tp->snd_cwnd); 463 } 464 } else if (tp->snd_cwnd > tp->snd_ssthresh && 465 icsk->icsk_ca_state == TCP_CA_Open) { 466 /* Cong. avoidance phase, cwnd is reliable. */ 467 if (!tcp_metric_locked(tm, TCP_METRIC_SSTHRESH)) 468 tcp_metric_set(tm, TCP_METRIC_SSTHRESH, 469 max(tp->snd_cwnd >> 1, tp->snd_ssthresh)); 470 if (!tcp_metric_locked(tm, TCP_METRIC_CWND)) { 471 val = tcp_metric_get(tm, TCP_METRIC_CWND); 472 tcp_metric_set(tm, TCP_METRIC_CWND, (val + tp->snd_cwnd) >> 1); 473 } 474 } else { 475 /* Else slow start did not finish, cwnd is non-sense, 476 * ssthresh may be also invalid. 477 */ 478 if (!tcp_metric_locked(tm, TCP_METRIC_CWND)) { 479 val = tcp_metric_get(tm, TCP_METRIC_CWND); 480 tcp_metric_set(tm, TCP_METRIC_CWND, 481 (val + tp->snd_ssthresh) >> 1); 482 } 483 if (!tcp_metric_locked(tm, TCP_METRIC_SSTHRESH)) { 484 val = tcp_metric_get(tm, TCP_METRIC_SSTHRESH); 485 if (val && tp->snd_ssthresh > val) 486 tcp_metric_set(tm, TCP_METRIC_SSTHRESH, 487 tp->snd_ssthresh); 488 } 489 if (!tcp_metric_locked(tm, TCP_METRIC_REORDERING)) { 490 val = tcp_metric_get(tm, TCP_METRIC_REORDERING); 491 if (val < tp->reordering && 492 tp->reordering != sysctl_tcp_reordering) 493 tcp_metric_set(tm, TCP_METRIC_REORDERING, 494 tp->reordering); 495 } 496 } 497 tm->tcpm_stamp = jiffies; 498 out_unlock: 499 rcu_read_unlock(); 500 } 501 502 /* Initialize metrics on socket. */ 503 504 void tcp_init_metrics(struct sock *sk) 505 { 506 struct dst_entry *dst = __sk_dst_get(sk); 507 struct tcp_sock *tp = tcp_sk(sk); 508 struct tcp_metrics_block *tm; 509 u32 val, crtt = 0; /* cached RTT scaled by 8 */ 510 511 if (!dst) 512 goto reset; 513 514 dst_confirm(dst); 515 516 rcu_read_lock(); 517 tm = tcp_get_metrics(sk, dst, true); 518 if (!tm) { 519 rcu_read_unlock(); 520 goto reset; 521 } 522 523 if (tcp_metric_locked(tm, TCP_METRIC_CWND)) 524 tp->snd_cwnd_clamp = tcp_metric_get(tm, TCP_METRIC_CWND); 525 526 val = tcp_metric_get(tm, TCP_METRIC_SSTHRESH); 527 if (val) { 528 tp->snd_ssthresh = val; 529 if (tp->snd_ssthresh > tp->snd_cwnd_clamp) 530 tp->snd_ssthresh = tp->snd_cwnd_clamp; 531 } else { 532 /* ssthresh may have been reduced unnecessarily during. 533 * 3WHS. Restore it back to its initial default. 534 */ 535 tp->snd_ssthresh = TCP_INFINITE_SSTHRESH; 536 } 537 val = tcp_metric_get(tm, TCP_METRIC_REORDERING); 538 if (val && tp->reordering != val) { 539 tcp_disable_fack(tp); 540 tcp_disable_early_retrans(tp); 541 tp->reordering = val; 542 } 543 544 crtt = tcp_metric_get(tm, TCP_METRIC_RTT); 545 rcu_read_unlock(); 546 reset: 547 /* The initial RTT measurement from the SYN/SYN-ACK is not ideal 548 * to seed the RTO for later data packets because SYN packets are 549 * small. Use the per-dst cached values to seed the RTO but keep 550 * the RTT estimator variables intact (e.g., srtt, mdev, rttvar). 551 * Later the RTO will be updated immediately upon obtaining the first 552 * data RTT sample (tcp_rtt_estimator()). Hence the cached RTT only 553 * influences the first RTO but not later RTT estimation. 554 * 555 * But if RTT is not available from the SYN (due to retransmits or 556 * syn cookies) or the cache, force a conservative 3secs timeout. 557 * 558 * A bit of theory. RTT is time passed after "normal" sized packet 559 * is sent until it is ACKed. In normal circumstances sending small 560 * packets force peer to delay ACKs and calculation is correct too. 561 * The algorithm is adaptive and, provided we follow specs, it 562 * NEVER underestimate RTT. BUT! If peer tries to make some clever 563 * tricks sort of "quick acks" for time long enough to decrease RTT 564 * to low value, and then abruptly stops to do it and starts to delay 565 * ACKs, wait for troubles. 566 */ 567 if (crtt > tp->srtt_us) { 568 /* Set RTO like tcp_rtt_estimator(), but from cached RTT. */ 569 crtt /= 8 * USEC_PER_MSEC; 570 inet_csk(sk)->icsk_rto = crtt + max(2 * crtt, tcp_rto_min(sk)); 571 } else if (tp->srtt_us == 0) { 572 /* RFC6298: 5.7 We've failed to get a valid RTT sample from 573 * 3WHS. This is most likely due to retransmission, 574 * including spurious one. Reset the RTO back to 3secs 575 * from the more aggressive 1sec to avoid more spurious 576 * retransmission. 577 */ 578 tp->rttvar_us = jiffies_to_usecs(TCP_TIMEOUT_FALLBACK); 579 tp->mdev_us = tp->mdev_max_us = tp->rttvar_us; 580 581 inet_csk(sk)->icsk_rto = TCP_TIMEOUT_FALLBACK; 582 } 583 /* Cut cwnd down to 1 per RFC5681 if SYN or SYN-ACK has been 584 * retransmitted. In light of RFC6298 more aggressive 1sec 585 * initRTO, we only reset cwnd when more than 1 SYN/SYN-ACK 586 * retransmission has occurred. 587 */ 588 if (tp->total_retrans > 1) 589 tp->snd_cwnd = 1; 590 else 591 tp->snd_cwnd = tcp_init_cwnd(tp, dst); 592 tp->snd_cwnd_stamp = tcp_time_stamp; 593 } 594 595 bool tcp_peer_is_proven(struct request_sock *req, struct dst_entry *dst, 596 bool paws_check, bool timestamps) 597 { 598 struct tcp_metrics_block *tm; 599 bool ret; 600 601 if (!dst) 602 return false; 603 604 rcu_read_lock(); 605 tm = __tcp_get_metrics_req(req, dst); 606 if (paws_check) { 607 if (tm && 608 (u32)get_seconds() - tm->tcpm_ts_stamp < TCP_PAWS_MSL && 609 ((s32)(tm->tcpm_ts - req->ts_recent) > TCP_PAWS_WINDOW || 610 !timestamps)) 611 ret = false; 612 else 613 ret = true; 614 } else { 615 if (tm && tcp_metric_get(tm, TCP_METRIC_RTT) && tm->tcpm_ts_stamp) 616 ret = true; 617 else 618 ret = false; 619 } 620 rcu_read_unlock(); 621 622 return ret; 623 } 624 EXPORT_SYMBOL_GPL(tcp_peer_is_proven); 625 626 void tcp_fetch_timewait_stamp(struct sock *sk, struct dst_entry *dst) 627 { 628 struct tcp_metrics_block *tm; 629 630 rcu_read_lock(); 631 tm = tcp_get_metrics(sk, dst, true); 632 if (tm) { 633 struct tcp_sock *tp = tcp_sk(sk); 634 635 if ((u32)get_seconds() - tm->tcpm_ts_stamp <= TCP_PAWS_MSL) { 636 tp->rx_opt.ts_recent_stamp = tm->tcpm_ts_stamp; 637 tp->rx_opt.ts_recent = tm->tcpm_ts; 638 } 639 } 640 rcu_read_unlock(); 641 } 642 EXPORT_SYMBOL_GPL(tcp_fetch_timewait_stamp); 643 644 /* VJ's idea. Save last timestamp seen from this destination and hold 645 * it at least for normal timewait interval to use for duplicate 646 * segment detection in subsequent connections, before they enter 647 * synchronized state. 648 */ 649 bool tcp_remember_stamp(struct sock *sk) 650 { 651 struct dst_entry *dst = __sk_dst_get(sk); 652 bool ret = false; 653 654 if (dst) { 655 struct tcp_metrics_block *tm; 656 657 rcu_read_lock(); 658 tm = tcp_get_metrics(sk, dst, true); 659 if (tm) { 660 struct tcp_sock *tp = tcp_sk(sk); 661 662 if ((s32)(tm->tcpm_ts - tp->rx_opt.ts_recent) <= 0 || 663 ((u32)get_seconds() - tm->tcpm_ts_stamp > TCP_PAWS_MSL && 664 tm->tcpm_ts_stamp <= (u32)tp->rx_opt.ts_recent_stamp)) { 665 tm->tcpm_ts_stamp = (u32)tp->rx_opt.ts_recent_stamp; 666 tm->tcpm_ts = tp->rx_opt.ts_recent; 667 } 668 ret = true; 669 } 670 rcu_read_unlock(); 671 } 672 return ret; 673 } 674 675 bool tcp_tw_remember_stamp(struct inet_timewait_sock *tw) 676 { 677 struct tcp_metrics_block *tm; 678 bool ret = false; 679 680 rcu_read_lock(); 681 tm = __tcp_get_metrics_tw(tw); 682 if (tm) { 683 const struct tcp_timewait_sock *tcptw; 684 struct sock *sk = (struct sock *) tw; 685 686 tcptw = tcp_twsk(sk); 687 if ((s32)(tm->tcpm_ts - tcptw->tw_ts_recent) <= 0 || 688 ((u32)get_seconds() - tm->tcpm_ts_stamp > TCP_PAWS_MSL && 689 tm->tcpm_ts_stamp <= (u32)tcptw->tw_ts_recent_stamp)) { 690 tm->tcpm_ts_stamp = (u32)tcptw->tw_ts_recent_stamp; 691 tm->tcpm_ts = tcptw->tw_ts_recent; 692 } 693 ret = true; 694 } 695 rcu_read_unlock(); 696 697 return ret; 698 } 699 700 static DEFINE_SEQLOCK(fastopen_seqlock); 701 702 void tcp_fastopen_cache_get(struct sock *sk, u16 *mss, 703 struct tcp_fastopen_cookie *cookie, 704 int *syn_loss, unsigned long *last_syn_loss) 705 { 706 struct tcp_metrics_block *tm; 707 708 rcu_read_lock(); 709 tm = tcp_get_metrics(sk, __sk_dst_get(sk), false); 710 if (tm) { 711 struct tcp_fastopen_metrics *tfom = &tm->tcpm_fastopen; 712 unsigned int seq; 713 714 do { 715 seq = read_seqbegin(&fastopen_seqlock); 716 if (tfom->mss) 717 *mss = tfom->mss; 718 *cookie = tfom->cookie; 719 if (cookie->len <= 0 && tfom->try_exp == 1) 720 cookie->exp = true; 721 *syn_loss = tfom->syn_loss; 722 *last_syn_loss = *syn_loss ? tfom->last_syn_loss : 0; 723 } while (read_seqretry(&fastopen_seqlock, seq)); 724 } 725 rcu_read_unlock(); 726 } 727 728 void tcp_fastopen_cache_set(struct sock *sk, u16 mss, 729 struct tcp_fastopen_cookie *cookie, bool syn_lost, 730 u16 try_exp) 731 { 732 struct dst_entry *dst = __sk_dst_get(sk); 733 struct tcp_metrics_block *tm; 734 735 if (!dst) 736 return; 737 rcu_read_lock(); 738 tm = tcp_get_metrics(sk, dst, true); 739 if (tm) { 740 struct tcp_fastopen_metrics *tfom = &tm->tcpm_fastopen; 741 742 write_seqlock_bh(&fastopen_seqlock); 743 if (mss) 744 tfom->mss = mss; 745 if (cookie && cookie->len > 0) 746 tfom->cookie = *cookie; 747 else if (try_exp > tfom->try_exp && 748 tfom->cookie.len <= 0 && !tfom->cookie.exp) 749 tfom->try_exp = try_exp; 750 if (syn_lost) { 751 ++tfom->syn_loss; 752 tfom->last_syn_loss = jiffies; 753 } else 754 tfom->syn_loss = 0; 755 write_sequnlock_bh(&fastopen_seqlock); 756 } 757 rcu_read_unlock(); 758 } 759 760 static struct genl_family tcp_metrics_nl_family = { 761 .id = GENL_ID_GENERATE, 762 .hdrsize = 0, 763 .name = TCP_METRICS_GENL_NAME, 764 .version = TCP_METRICS_GENL_VERSION, 765 .maxattr = TCP_METRICS_ATTR_MAX, 766 .netnsok = true, 767 }; 768 769 static struct nla_policy tcp_metrics_nl_policy[TCP_METRICS_ATTR_MAX + 1] = { 770 [TCP_METRICS_ATTR_ADDR_IPV4] = { .type = NLA_U32, }, 771 [TCP_METRICS_ATTR_ADDR_IPV6] = { .type = NLA_BINARY, 772 .len = sizeof(struct in6_addr), }, 773 /* Following attributes are not received for GET/DEL, 774 * we keep them for reference 775 */ 776 #if 0 777 [TCP_METRICS_ATTR_AGE] = { .type = NLA_MSECS, }, 778 [TCP_METRICS_ATTR_TW_TSVAL] = { .type = NLA_U32, }, 779 [TCP_METRICS_ATTR_TW_TS_STAMP] = { .type = NLA_S32, }, 780 [TCP_METRICS_ATTR_VALS] = { .type = NLA_NESTED, }, 781 [TCP_METRICS_ATTR_FOPEN_MSS] = { .type = NLA_U16, }, 782 [TCP_METRICS_ATTR_FOPEN_SYN_DROPS] = { .type = NLA_U16, }, 783 [TCP_METRICS_ATTR_FOPEN_SYN_DROP_TS] = { .type = NLA_MSECS, }, 784 [TCP_METRICS_ATTR_FOPEN_COOKIE] = { .type = NLA_BINARY, 785 .len = TCP_FASTOPEN_COOKIE_MAX, }, 786 #endif 787 }; 788 789 /* Add attributes, caller cancels its header on failure */ 790 static int tcp_metrics_fill_info(struct sk_buff *msg, 791 struct tcp_metrics_block *tm) 792 { 793 struct nlattr *nest; 794 int i; 795 796 switch (tm->tcpm_daddr.family) { 797 case AF_INET: 798 if (nla_put_in_addr(msg, TCP_METRICS_ATTR_ADDR_IPV4, 799 tm->tcpm_daddr.addr.a4) < 0) 800 goto nla_put_failure; 801 if (nla_put_in_addr(msg, TCP_METRICS_ATTR_SADDR_IPV4, 802 tm->tcpm_saddr.addr.a4) < 0) 803 goto nla_put_failure; 804 break; 805 case AF_INET6: 806 if (nla_put_in6_addr(msg, TCP_METRICS_ATTR_ADDR_IPV6, 807 &tm->tcpm_daddr.addr.in6) < 0) 808 goto nla_put_failure; 809 if (nla_put_in6_addr(msg, TCP_METRICS_ATTR_SADDR_IPV6, 810 &tm->tcpm_saddr.addr.in6) < 0) 811 goto nla_put_failure; 812 break; 813 default: 814 return -EAFNOSUPPORT; 815 } 816 817 if (nla_put_msecs(msg, TCP_METRICS_ATTR_AGE, 818 jiffies - tm->tcpm_stamp) < 0) 819 goto nla_put_failure; 820 if (tm->tcpm_ts_stamp) { 821 if (nla_put_s32(msg, TCP_METRICS_ATTR_TW_TS_STAMP, 822 (s32) (get_seconds() - tm->tcpm_ts_stamp)) < 0) 823 goto nla_put_failure; 824 if (nla_put_u32(msg, TCP_METRICS_ATTR_TW_TSVAL, 825 tm->tcpm_ts) < 0) 826 goto nla_put_failure; 827 } 828 829 { 830 int n = 0; 831 832 nest = nla_nest_start(msg, TCP_METRICS_ATTR_VALS); 833 if (!nest) 834 goto nla_put_failure; 835 for (i = 0; i < TCP_METRIC_MAX_KERNEL + 1; i++) { 836 u32 val = tm->tcpm_vals[i]; 837 838 if (!val) 839 continue; 840 if (i == TCP_METRIC_RTT) { 841 if (nla_put_u32(msg, TCP_METRIC_RTT_US + 1, 842 val) < 0) 843 goto nla_put_failure; 844 n++; 845 val = max(val / 1000, 1U); 846 } 847 if (i == TCP_METRIC_RTTVAR) { 848 if (nla_put_u32(msg, TCP_METRIC_RTTVAR_US + 1, 849 val) < 0) 850 goto nla_put_failure; 851 n++; 852 val = max(val / 1000, 1U); 853 } 854 if (nla_put_u32(msg, i + 1, val) < 0) 855 goto nla_put_failure; 856 n++; 857 } 858 if (n) 859 nla_nest_end(msg, nest); 860 else 861 nla_nest_cancel(msg, nest); 862 } 863 864 { 865 struct tcp_fastopen_metrics tfom_copy[1], *tfom; 866 unsigned int seq; 867 868 do { 869 seq = read_seqbegin(&fastopen_seqlock); 870 tfom_copy[0] = tm->tcpm_fastopen; 871 } while (read_seqretry(&fastopen_seqlock, seq)); 872 873 tfom = tfom_copy; 874 if (tfom->mss && 875 nla_put_u16(msg, TCP_METRICS_ATTR_FOPEN_MSS, 876 tfom->mss) < 0) 877 goto nla_put_failure; 878 if (tfom->syn_loss && 879 (nla_put_u16(msg, TCP_METRICS_ATTR_FOPEN_SYN_DROPS, 880 tfom->syn_loss) < 0 || 881 nla_put_msecs(msg, TCP_METRICS_ATTR_FOPEN_SYN_DROP_TS, 882 jiffies - tfom->last_syn_loss) < 0)) 883 goto nla_put_failure; 884 if (tfom->cookie.len > 0 && 885 nla_put(msg, TCP_METRICS_ATTR_FOPEN_COOKIE, 886 tfom->cookie.len, tfom->cookie.val) < 0) 887 goto nla_put_failure; 888 } 889 890 return 0; 891 892 nla_put_failure: 893 return -EMSGSIZE; 894 } 895 896 static int tcp_metrics_dump_info(struct sk_buff *skb, 897 struct netlink_callback *cb, 898 struct tcp_metrics_block *tm) 899 { 900 void *hdr; 901 902 hdr = genlmsg_put(skb, NETLINK_CB(cb->skb).portid, cb->nlh->nlmsg_seq, 903 &tcp_metrics_nl_family, NLM_F_MULTI, 904 TCP_METRICS_CMD_GET); 905 if (!hdr) 906 return -EMSGSIZE; 907 908 if (tcp_metrics_fill_info(skb, tm) < 0) 909 goto nla_put_failure; 910 911 genlmsg_end(skb, hdr); 912 return 0; 913 914 nla_put_failure: 915 genlmsg_cancel(skb, hdr); 916 return -EMSGSIZE; 917 } 918 919 static int tcp_metrics_nl_dump(struct sk_buff *skb, 920 struct netlink_callback *cb) 921 { 922 struct net *net = sock_net(skb->sk); 923 unsigned int max_rows = 1U << tcp_metrics_hash_log; 924 unsigned int row, s_row = cb->args[0]; 925 int s_col = cb->args[1], col = s_col; 926 927 for (row = s_row; row < max_rows; row++, s_col = 0) { 928 struct tcp_metrics_block *tm; 929 struct tcpm_hash_bucket *hb = tcp_metrics_hash + row; 930 931 rcu_read_lock(); 932 for (col = 0, tm = rcu_dereference(hb->chain); tm; 933 tm = rcu_dereference(tm->tcpm_next), col++) { 934 if (!net_eq(tm_net(tm), net)) 935 continue; 936 if (col < s_col) 937 continue; 938 if (tcp_metrics_dump_info(skb, cb, tm) < 0) { 939 rcu_read_unlock(); 940 goto done; 941 } 942 } 943 rcu_read_unlock(); 944 } 945 946 done: 947 cb->args[0] = row; 948 cb->args[1] = col; 949 return skb->len; 950 } 951 952 static int __parse_nl_addr(struct genl_info *info, struct inetpeer_addr *addr, 953 unsigned int *hash, int optional, int v4, int v6) 954 { 955 struct nlattr *a; 956 957 a = info->attrs[v4]; 958 if (a) { 959 addr->family = AF_INET; 960 addr->addr.a4 = nla_get_in_addr(a); 961 if (hash) 962 *hash = (__force unsigned int) addr->addr.a4; 963 return 0; 964 } 965 a = info->attrs[v6]; 966 if (a) { 967 if (nla_len(a) != sizeof(struct in6_addr)) 968 return -EINVAL; 969 addr->family = AF_INET6; 970 addr->addr.in6 = nla_get_in6_addr(a); 971 if (hash) 972 *hash = ipv6_addr_hash(&addr->addr.in6); 973 return 0; 974 } 975 return optional ? 1 : -EAFNOSUPPORT; 976 } 977 978 static int parse_nl_addr(struct genl_info *info, struct inetpeer_addr *addr, 979 unsigned int *hash, int optional) 980 { 981 return __parse_nl_addr(info, addr, hash, optional, 982 TCP_METRICS_ATTR_ADDR_IPV4, 983 TCP_METRICS_ATTR_ADDR_IPV6); 984 } 985 986 static int parse_nl_saddr(struct genl_info *info, struct inetpeer_addr *addr) 987 { 988 return __parse_nl_addr(info, addr, NULL, 0, 989 TCP_METRICS_ATTR_SADDR_IPV4, 990 TCP_METRICS_ATTR_SADDR_IPV6); 991 } 992 993 static int tcp_metrics_nl_cmd_get(struct sk_buff *skb, struct genl_info *info) 994 { 995 struct tcp_metrics_block *tm; 996 struct inetpeer_addr saddr, daddr; 997 unsigned int hash; 998 struct sk_buff *msg; 999 struct net *net = genl_info_net(info); 1000 void *reply; 1001 int ret; 1002 bool src = true; 1003 1004 ret = parse_nl_addr(info, &daddr, &hash, 0); 1005 if (ret < 0) 1006 return ret; 1007 1008 ret = parse_nl_saddr(info, &saddr); 1009 if (ret < 0) 1010 src = false; 1011 1012 msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL); 1013 if (!msg) 1014 return -ENOMEM; 1015 1016 reply = genlmsg_put_reply(msg, info, &tcp_metrics_nl_family, 0, 1017 info->genlhdr->cmd); 1018 if (!reply) 1019 goto nla_put_failure; 1020 1021 hash ^= net_hash_mix(net); 1022 hash = hash_32(hash, tcp_metrics_hash_log); 1023 ret = -ESRCH; 1024 rcu_read_lock(); 1025 for (tm = rcu_dereference(tcp_metrics_hash[hash].chain); tm; 1026 tm = rcu_dereference(tm->tcpm_next)) { 1027 if (addr_same(&tm->tcpm_daddr, &daddr) && 1028 (!src || addr_same(&tm->tcpm_saddr, &saddr)) && 1029 net_eq(tm_net(tm), net)) { 1030 ret = tcp_metrics_fill_info(msg, tm); 1031 break; 1032 } 1033 } 1034 rcu_read_unlock(); 1035 if (ret < 0) 1036 goto out_free; 1037 1038 genlmsg_end(msg, reply); 1039 return genlmsg_reply(msg, info); 1040 1041 nla_put_failure: 1042 ret = -EMSGSIZE; 1043 1044 out_free: 1045 nlmsg_free(msg); 1046 return ret; 1047 } 1048 1049 static void tcp_metrics_flush_all(struct net *net) 1050 { 1051 unsigned int max_rows = 1U << tcp_metrics_hash_log; 1052 struct tcpm_hash_bucket *hb = tcp_metrics_hash; 1053 struct tcp_metrics_block *tm; 1054 unsigned int row; 1055 1056 for (row = 0; row < max_rows; row++, hb++) { 1057 struct tcp_metrics_block __rcu **pp; 1058 spin_lock_bh(&tcp_metrics_lock); 1059 pp = &hb->chain; 1060 for (tm = deref_locked(*pp); tm; tm = deref_locked(*pp)) { 1061 if (net_eq(tm_net(tm), net)) { 1062 *pp = tm->tcpm_next; 1063 kfree_rcu(tm, rcu_head); 1064 } else { 1065 pp = &tm->tcpm_next; 1066 } 1067 } 1068 spin_unlock_bh(&tcp_metrics_lock); 1069 } 1070 } 1071 1072 static int tcp_metrics_nl_cmd_del(struct sk_buff *skb, struct genl_info *info) 1073 { 1074 struct tcpm_hash_bucket *hb; 1075 struct tcp_metrics_block *tm; 1076 struct tcp_metrics_block __rcu **pp; 1077 struct inetpeer_addr saddr, daddr; 1078 unsigned int hash; 1079 struct net *net = genl_info_net(info); 1080 int ret; 1081 bool src = true, found = false; 1082 1083 ret = parse_nl_addr(info, &daddr, &hash, 1); 1084 if (ret < 0) 1085 return ret; 1086 if (ret > 0) { 1087 tcp_metrics_flush_all(net); 1088 return 0; 1089 } 1090 ret = parse_nl_saddr(info, &saddr); 1091 if (ret < 0) 1092 src = false; 1093 1094 hash ^= net_hash_mix(net); 1095 hash = hash_32(hash, tcp_metrics_hash_log); 1096 hb = tcp_metrics_hash + hash; 1097 pp = &hb->chain; 1098 spin_lock_bh(&tcp_metrics_lock); 1099 for (tm = deref_locked(*pp); tm; tm = deref_locked(*pp)) { 1100 if (addr_same(&tm->tcpm_daddr, &daddr) && 1101 (!src || addr_same(&tm->tcpm_saddr, &saddr)) && 1102 net_eq(tm_net(tm), net)) { 1103 *pp = tm->tcpm_next; 1104 kfree_rcu(tm, rcu_head); 1105 found = true; 1106 } else { 1107 pp = &tm->tcpm_next; 1108 } 1109 } 1110 spin_unlock_bh(&tcp_metrics_lock); 1111 if (!found) 1112 return -ESRCH; 1113 return 0; 1114 } 1115 1116 static const struct genl_ops tcp_metrics_nl_ops[] = { 1117 { 1118 .cmd = TCP_METRICS_CMD_GET, 1119 .doit = tcp_metrics_nl_cmd_get, 1120 .dumpit = tcp_metrics_nl_dump, 1121 .policy = tcp_metrics_nl_policy, 1122 }, 1123 { 1124 .cmd = TCP_METRICS_CMD_DEL, 1125 .doit = tcp_metrics_nl_cmd_del, 1126 .policy = tcp_metrics_nl_policy, 1127 .flags = GENL_ADMIN_PERM, 1128 }, 1129 }; 1130 1131 static unsigned int tcpmhash_entries; 1132 static int __init set_tcpmhash_entries(char *str) 1133 { 1134 ssize_t ret; 1135 1136 if (!str) 1137 return 0; 1138 1139 ret = kstrtouint(str, 0, &tcpmhash_entries); 1140 if (ret) 1141 return 0; 1142 1143 return 1; 1144 } 1145 __setup("tcpmhash_entries=", set_tcpmhash_entries); 1146 1147 static int __net_init tcp_net_metrics_init(struct net *net) 1148 { 1149 size_t size; 1150 unsigned int slots; 1151 1152 if (!net_eq(net, &init_net)) 1153 return 0; 1154 1155 slots = tcpmhash_entries; 1156 if (!slots) { 1157 if (totalram_pages >= 128 * 1024) 1158 slots = 16 * 1024; 1159 else 1160 slots = 8 * 1024; 1161 } 1162 1163 tcp_metrics_hash_log = order_base_2(slots); 1164 size = sizeof(struct tcpm_hash_bucket) << tcp_metrics_hash_log; 1165 1166 tcp_metrics_hash = kzalloc(size, GFP_KERNEL | __GFP_NOWARN); 1167 if (!tcp_metrics_hash) 1168 tcp_metrics_hash = vzalloc(size); 1169 1170 if (!tcp_metrics_hash) 1171 return -ENOMEM; 1172 1173 return 0; 1174 } 1175 1176 static void __net_exit tcp_net_metrics_exit(struct net *net) 1177 { 1178 tcp_metrics_flush_all(net); 1179 } 1180 1181 static __net_initdata struct pernet_operations tcp_net_metrics_ops = { 1182 .init = tcp_net_metrics_init, 1183 .exit = tcp_net_metrics_exit, 1184 }; 1185 1186 void __init tcp_metrics_init(void) 1187 { 1188 int ret; 1189 1190 ret = register_pernet_subsys(&tcp_net_metrics_ops); 1191 if (ret < 0) 1192 panic("Could not allocate the tcp_metrics hash table\n"); 1193 1194 ret = genl_register_family_with_ops(&tcp_metrics_nl_family, 1195 tcp_metrics_nl_ops); 1196 if (ret < 0) 1197 panic("Could not register tcp_metrics generic netlink\n"); 1198 } 1199