1 // SPDX-License-Identifier: GPL-2.0 2 #include <linux/rcupdate.h> 3 #include <linux/spinlock.h> 4 #include <linux/jiffies.h> 5 #include <linux/module.h> 6 #include <linux/cache.h> 7 #include <linux/slab.h> 8 #include <linux/init.h> 9 #include <linux/tcp.h> 10 #include <linux/hash.h> 11 #include <linux/tcp_metrics.h> 12 #include <linux/vmalloc.h> 13 14 #include <net/inet_connection_sock.h> 15 #include <net/net_namespace.h> 16 #include <net/request_sock.h> 17 #include <net/inetpeer.h> 18 #include <net/sock.h> 19 #include <net/ipv6.h> 20 #include <net/dst.h> 21 #include <net/tcp.h> 22 #include <net/genetlink.h> 23 24 static struct tcp_metrics_block *__tcp_get_metrics(const struct inetpeer_addr *saddr, 25 const struct inetpeer_addr *daddr, 26 struct net *net, unsigned int hash); 27 28 struct tcp_fastopen_metrics { 29 u16 mss; 30 u16 syn_loss:10, /* Recurring Fast Open SYN losses */ 31 try_exp:2; /* Request w/ exp. option (once) */ 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 41 struct tcp_metrics_block { 42 struct tcp_metrics_block __rcu *tcpm_next; 43 struct net *tcpm_net; 44 struct inetpeer_addr tcpm_saddr; 45 struct inetpeer_addr tcpm_daddr; 46 unsigned long tcpm_stamp; 47 u32 tcpm_lock; 48 u32 tcpm_vals[TCP_METRIC_MAX_KERNEL + 1]; 49 struct tcp_fastopen_metrics tcpm_fastopen; 50 51 struct rcu_head rcu_head; 52 }; 53 54 static inline struct net *tm_net(const struct tcp_metrics_block *tm) 55 { 56 /* Paired with the WRITE_ONCE() in tcpm_new() */ 57 return READ_ONCE(tm->tcpm_net); 58 } 59 60 static bool tcp_metric_locked(struct tcp_metrics_block *tm, 61 enum tcp_metric_index idx) 62 { 63 /* Paired with WRITE_ONCE() in tcpm_suck_dst() */ 64 return READ_ONCE(tm->tcpm_lock) & (1 << idx); 65 } 66 67 static u32 tcp_metric_get(const struct tcp_metrics_block *tm, 68 enum tcp_metric_index idx) 69 { 70 /* Paired with WRITE_ONCE() in tcp_metric_set() */ 71 return READ_ONCE(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 /* Paired with READ_ONCE() in tcp_metric_get() */ 79 WRITE_ONCE(tm->tcpm_vals[idx], val); 80 } 81 82 static bool addr_same(const struct inetpeer_addr *a, 83 const struct inetpeer_addr *b) 84 { 85 return (a->family == b->family) && !inetpeer_addr_cmp(a, b); 86 } 87 88 struct tcpm_hash_bucket { 89 struct tcp_metrics_block __rcu *chain; 90 }; 91 92 static struct tcpm_hash_bucket *tcp_metrics_hash __read_mostly; 93 static unsigned int tcp_metrics_hash_log __read_mostly; 94 95 static DEFINE_SPINLOCK(tcp_metrics_lock); 96 static DEFINE_SEQLOCK(fastopen_seqlock); 97 98 static void tcpm_suck_dst(struct tcp_metrics_block *tm, 99 const struct dst_entry *dst, 100 bool fastopen_clear) 101 { 102 u32 msval; 103 u32 val; 104 105 WRITE_ONCE(tm->tcpm_stamp, jiffies); 106 107 val = 0; 108 if (dst_metric_locked(dst, RTAX_RTT)) 109 val |= 1 << TCP_METRIC_RTT; 110 if (dst_metric_locked(dst, RTAX_RTTVAR)) 111 val |= 1 << TCP_METRIC_RTTVAR; 112 if (dst_metric_locked(dst, RTAX_SSTHRESH)) 113 val |= 1 << TCP_METRIC_SSTHRESH; 114 if (dst_metric_locked(dst, RTAX_CWND)) 115 val |= 1 << TCP_METRIC_CWND; 116 if (dst_metric_locked(dst, RTAX_REORDERING)) 117 val |= 1 << TCP_METRIC_REORDERING; 118 /* Paired with READ_ONCE() in tcp_metric_locked() */ 119 WRITE_ONCE(tm->tcpm_lock, val); 120 121 msval = dst_metric_raw(dst, RTAX_RTT); 122 tcp_metric_set(tm, TCP_METRIC_RTT, msval * USEC_PER_MSEC); 123 124 msval = dst_metric_raw(dst, RTAX_RTTVAR); 125 tcp_metric_set(tm, TCP_METRIC_RTTVAR, msval * USEC_PER_MSEC); 126 tcp_metric_set(tm, TCP_METRIC_SSTHRESH, 127 dst_metric_raw(dst, RTAX_SSTHRESH)); 128 tcp_metric_set(tm, TCP_METRIC_CWND, 129 dst_metric_raw(dst, RTAX_CWND)); 130 tcp_metric_set(tm, TCP_METRIC_REORDERING, 131 dst_metric_raw(dst, RTAX_REORDERING)); 132 if (fastopen_clear) { 133 write_seqlock(&fastopen_seqlock); 134 tm->tcpm_fastopen.mss = 0; 135 tm->tcpm_fastopen.syn_loss = 0; 136 tm->tcpm_fastopen.try_exp = 0; 137 tm->tcpm_fastopen.cookie.exp = false; 138 tm->tcpm_fastopen.cookie.len = 0; 139 write_sequnlock(&fastopen_seqlock); 140 } 141 } 142 143 #define TCP_METRICS_TIMEOUT (60 * 60 * HZ) 144 145 static void tcpm_check_stamp(struct tcp_metrics_block *tm, 146 const struct dst_entry *dst) 147 { 148 unsigned long limit; 149 150 if (!tm) 151 return; 152 limit = READ_ONCE(tm->tcpm_stamp) + TCP_METRICS_TIMEOUT; 153 if (unlikely(time_after(jiffies, limit))) 154 tcpm_suck_dst(tm, dst, false); 155 } 156 157 #define TCP_METRICS_RECLAIM_DEPTH 5 158 #define TCP_METRICS_RECLAIM_PTR (struct tcp_metrics_block *) 0x1UL 159 160 #define deref_locked(p) \ 161 rcu_dereference_protected(p, lockdep_is_held(&tcp_metrics_lock)) 162 163 static struct tcp_metrics_block *tcpm_new(struct dst_entry *dst, 164 struct inetpeer_addr *saddr, 165 struct inetpeer_addr *daddr, 166 unsigned int hash) 167 { 168 struct tcp_metrics_block *tm; 169 struct net *net; 170 bool reclaim = false; 171 172 spin_lock_bh(&tcp_metrics_lock); 173 net = dev_net(dst->dev); 174 175 /* While waiting for the spin-lock the cache might have been populated 176 * with this entry and so we have to check again. 177 */ 178 tm = __tcp_get_metrics(saddr, daddr, net, hash); 179 if (tm == TCP_METRICS_RECLAIM_PTR) { 180 reclaim = true; 181 tm = NULL; 182 } 183 if (tm) { 184 tcpm_check_stamp(tm, dst); 185 goto out_unlock; 186 } 187 188 if (unlikely(reclaim)) { 189 struct tcp_metrics_block *oldest; 190 191 oldest = deref_locked(tcp_metrics_hash[hash].chain); 192 for (tm = deref_locked(oldest->tcpm_next); tm; 193 tm = deref_locked(tm->tcpm_next)) { 194 if (time_before(READ_ONCE(tm->tcpm_stamp), 195 READ_ONCE(oldest->tcpm_stamp))) 196 oldest = tm; 197 } 198 tm = oldest; 199 } else { 200 tm = kzalloc(sizeof(*tm), GFP_ATOMIC); 201 if (!tm) 202 goto out_unlock; 203 } 204 /* Paired with the READ_ONCE() in tm_net() */ 205 WRITE_ONCE(tm->tcpm_net, net); 206 207 tm->tcpm_saddr = *saddr; 208 tm->tcpm_daddr = *daddr; 209 210 tcpm_suck_dst(tm, dst, reclaim); 211 212 if (likely(!reclaim)) { 213 tm->tcpm_next = tcp_metrics_hash[hash].chain; 214 rcu_assign_pointer(tcp_metrics_hash[hash].chain, tm); 215 } 216 217 out_unlock: 218 spin_unlock_bh(&tcp_metrics_lock); 219 return tm; 220 } 221 222 static struct tcp_metrics_block *tcp_get_encode(struct tcp_metrics_block *tm, int depth) 223 { 224 if (tm) 225 return tm; 226 if (depth > TCP_METRICS_RECLAIM_DEPTH) 227 return TCP_METRICS_RECLAIM_PTR; 228 return NULL; 229 } 230 231 static struct tcp_metrics_block *__tcp_get_metrics(const struct inetpeer_addr *saddr, 232 const struct inetpeer_addr *daddr, 233 struct net *net, unsigned int hash) 234 { 235 struct tcp_metrics_block *tm; 236 int depth = 0; 237 238 for (tm = rcu_dereference(tcp_metrics_hash[hash].chain); tm; 239 tm = rcu_dereference(tm->tcpm_next)) { 240 if (addr_same(&tm->tcpm_saddr, saddr) && 241 addr_same(&tm->tcpm_daddr, daddr) && 242 net_eq(tm_net(tm), net)) 243 break; 244 depth++; 245 } 246 return tcp_get_encode(tm, depth); 247 } 248 249 static struct tcp_metrics_block *__tcp_get_metrics_req(struct request_sock *req, 250 struct dst_entry *dst) 251 { 252 struct tcp_metrics_block *tm; 253 struct inetpeer_addr saddr, daddr; 254 unsigned int hash; 255 struct net *net; 256 257 saddr.family = req->rsk_ops->family; 258 daddr.family = req->rsk_ops->family; 259 switch (daddr.family) { 260 case AF_INET: 261 inetpeer_set_addr_v4(&saddr, inet_rsk(req)->ir_loc_addr); 262 inetpeer_set_addr_v4(&daddr, inet_rsk(req)->ir_rmt_addr); 263 hash = ipv4_addr_hash(inet_rsk(req)->ir_rmt_addr); 264 break; 265 #if IS_ENABLED(CONFIG_IPV6) 266 case AF_INET6: 267 inetpeer_set_addr_v6(&saddr, &inet_rsk(req)->ir_v6_loc_addr); 268 inetpeer_set_addr_v6(&daddr, &inet_rsk(req)->ir_v6_rmt_addr); 269 hash = ipv6_addr_hash(&inet_rsk(req)->ir_v6_rmt_addr); 270 break; 271 #endif 272 default: 273 return NULL; 274 } 275 276 net = dev_net(dst->dev); 277 hash ^= net_hash_mix(net); 278 hash = hash_32(hash, tcp_metrics_hash_log); 279 280 for (tm = rcu_dereference(tcp_metrics_hash[hash].chain); tm; 281 tm = rcu_dereference(tm->tcpm_next)) { 282 if (addr_same(&tm->tcpm_saddr, &saddr) && 283 addr_same(&tm->tcpm_daddr, &daddr) && 284 net_eq(tm_net(tm), net)) 285 break; 286 } 287 tcpm_check_stamp(tm, dst); 288 return tm; 289 } 290 291 static struct tcp_metrics_block *tcp_get_metrics(struct sock *sk, 292 struct dst_entry *dst, 293 bool create) 294 { 295 struct tcp_metrics_block *tm; 296 struct inetpeer_addr saddr, daddr; 297 unsigned int hash; 298 struct net *net; 299 300 if (sk->sk_family == AF_INET) { 301 inetpeer_set_addr_v4(&saddr, inet_sk(sk)->inet_saddr); 302 inetpeer_set_addr_v4(&daddr, inet_sk(sk)->inet_daddr); 303 hash = ipv4_addr_hash(inet_sk(sk)->inet_daddr); 304 } 305 #if IS_ENABLED(CONFIG_IPV6) 306 else if (sk->sk_family == AF_INET6) { 307 if (ipv6_addr_v4mapped(&sk->sk_v6_daddr)) { 308 inetpeer_set_addr_v4(&saddr, inet_sk(sk)->inet_saddr); 309 inetpeer_set_addr_v4(&daddr, inet_sk(sk)->inet_daddr); 310 hash = ipv4_addr_hash(inet_sk(sk)->inet_daddr); 311 } else { 312 inetpeer_set_addr_v6(&saddr, &sk->sk_v6_rcv_saddr); 313 inetpeer_set_addr_v6(&daddr, &sk->sk_v6_daddr); 314 hash = ipv6_addr_hash(&sk->sk_v6_daddr); 315 } 316 } 317 #endif 318 else 319 return NULL; 320 321 net = dev_net(dst->dev); 322 hash ^= net_hash_mix(net); 323 hash = hash_32(hash, tcp_metrics_hash_log); 324 325 tm = __tcp_get_metrics(&saddr, &daddr, net, hash); 326 if (tm == TCP_METRICS_RECLAIM_PTR) 327 tm = NULL; 328 if (!tm && create) 329 tm = tcpm_new(dst, &saddr, &daddr, hash); 330 else 331 tcpm_check_stamp(tm, dst); 332 333 return tm; 334 } 335 336 /* Save metrics learned by this TCP session. This function is called 337 * only, when TCP finishes successfully i.e. when it enters TIME-WAIT 338 * or goes from LAST-ACK to CLOSE. 339 */ 340 void tcp_update_metrics(struct sock *sk) 341 { 342 const struct inet_connection_sock *icsk = inet_csk(sk); 343 struct dst_entry *dst = __sk_dst_get(sk); 344 struct tcp_sock *tp = tcp_sk(sk); 345 struct net *net = sock_net(sk); 346 struct tcp_metrics_block *tm; 347 unsigned long rtt; 348 u32 val; 349 int m; 350 351 sk_dst_confirm(sk); 352 if (READ_ONCE(net->ipv4.sysctl_tcp_nometrics_save) || !dst) 353 return; 354 355 rcu_read_lock(); 356 if (icsk->icsk_backoff || !tp->srtt_us) { 357 /* This session failed to estimate rtt. Why? 358 * Probably, no packets returned in time. Reset our 359 * results. 360 */ 361 tm = tcp_get_metrics(sk, dst, false); 362 if (tm && !tcp_metric_locked(tm, TCP_METRIC_RTT)) 363 tcp_metric_set(tm, TCP_METRIC_RTT, 0); 364 goto out_unlock; 365 } else 366 tm = tcp_get_metrics(sk, dst, true); 367 368 if (!tm) 369 goto out_unlock; 370 371 rtt = tcp_metric_get(tm, TCP_METRIC_RTT); 372 m = rtt - tp->srtt_us; 373 374 /* If newly calculated rtt larger than stored one, store new 375 * one. Otherwise, use EWMA. Remember, rtt overestimation is 376 * always better than underestimation. 377 */ 378 if (!tcp_metric_locked(tm, TCP_METRIC_RTT)) { 379 if (m <= 0) 380 rtt = tp->srtt_us; 381 else 382 rtt -= (m >> 3); 383 tcp_metric_set(tm, TCP_METRIC_RTT, rtt); 384 } 385 386 if (!tcp_metric_locked(tm, TCP_METRIC_RTTVAR)) { 387 unsigned long var; 388 389 if (m < 0) 390 m = -m; 391 392 /* Scale deviation to rttvar fixed point */ 393 m >>= 1; 394 if (m < tp->mdev_us) 395 m = tp->mdev_us; 396 397 var = tcp_metric_get(tm, TCP_METRIC_RTTVAR); 398 if (m >= var) 399 var = m; 400 else 401 var -= (var - m) >> 2; 402 403 tcp_metric_set(tm, TCP_METRIC_RTTVAR, var); 404 } 405 406 if (tcp_in_initial_slowstart(tp)) { 407 /* Slow start still did not finish. */ 408 if (!READ_ONCE(net->ipv4.sysctl_tcp_no_ssthresh_metrics_save) && 409 !tcp_metric_locked(tm, TCP_METRIC_SSTHRESH)) { 410 val = tcp_metric_get(tm, TCP_METRIC_SSTHRESH); 411 if (val && (tcp_snd_cwnd(tp) >> 1) > val) 412 tcp_metric_set(tm, TCP_METRIC_SSTHRESH, 413 tcp_snd_cwnd(tp) >> 1); 414 } 415 if (!tcp_metric_locked(tm, TCP_METRIC_CWND)) { 416 val = tcp_metric_get(tm, TCP_METRIC_CWND); 417 if (tcp_snd_cwnd(tp) > val) 418 tcp_metric_set(tm, TCP_METRIC_CWND, 419 tcp_snd_cwnd(tp)); 420 } 421 } else if (!tcp_in_slow_start(tp) && 422 icsk->icsk_ca_state == TCP_CA_Open) { 423 /* Cong. avoidance phase, cwnd is reliable. */ 424 if (!READ_ONCE(net->ipv4.sysctl_tcp_no_ssthresh_metrics_save) && 425 !tcp_metric_locked(tm, TCP_METRIC_SSTHRESH)) 426 tcp_metric_set(tm, TCP_METRIC_SSTHRESH, 427 max(tcp_snd_cwnd(tp) >> 1, tp->snd_ssthresh)); 428 if (!tcp_metric_locked(tm, TCP_METRIC_CWND)) { 429 val = tcp_metric_get(tm, TCP_METRIC_CWND); 430 tcp_metric_set(tm, TCP_METRIC_CWND, (val + tcp_snd_cwnd(tp)) >> 1); 431 } 432 } else { 433 /* Else slow start did not finish, cwnd is non-sense, 434 * ssthresh may be also invalid. 435 */ 436 if (!tcp_metric_locked(tm, TCP_METRIC_CWND)) { 437 val = tcp_metric_get(tm, TCP_METRIC_CWND); 438 tcp_metric_set(tm, TCP_METRIC_CWND, 439 (val + tp->snd_ssthresh) >> 1); 440 } 441 if (!READ_ONCE(net->ipv4.sysctl_tcp_no_ssthresh_metrics_save) && 442 !tcp_metric_locked(tm, TCP_METRIC_SSTHRESH)) { 443 val = tcp_metric_get(tm, TCP_METRIC_SSTHRESH); 444 if (val && tp->snd_ssthresh > val) 445 tcp_metric_set(tm, TCP_METRIC_SSTHRESH, 446 tp->snd_ssthresh); 447 } 448 if (!tcp_metric_locked(tm, TCP_METRIC_REORDERING)) { 449 val = tcp_metric_get(tm, TCP_METRIC_REORDERING); 450 if (val < tp->reordering && 451 tp->reordering != 452 READ_ONCE(net->ipv4.sysctl_tcp_reordering)) 453 tcp_metric_set(tm, TCP_METRIC_REORDERING, 454 tp->reordering); 455 } 456 } 457 WRITE_ONCE(tm->tcpm_stamp, jiffies); 458 out_unlock: 459 rcu_read_unlock(); 460 } 461 462 /* Initialize metrics on socket. */ 463 464 void tcp_init_metrics(struct sock *sk) 465 { 466 struct dst_entry *dst = __sk_dst_get(sk); 467 struct tcp_sock *tp = tcp_sk(sk); 468 struct net *net = sock_net(sk); 469 struct tcp_metrics_block *tm; 470 u32 val, crtt = 0; /* cached RTT scaled by 8 */ 471 472 sk_dst_confirm(sk); 473 if (!dst) 474 goto reset; 475 476 rcu_read_lock(); 477 tm = tcp_get_metrics(sk, dst, true); 478 if (!tm) { 479 rcu_read_unlock(); 480 goto reset; 481 } 482 483 if (tcp_metric_locked(tm, TCP_METRIC_CWND)) 484 tp->snd_cwnd_clamp = tcp_metric_get(tm, TCP_METRIC_CWND); 485 486 val = READ_ONCE(net->ipv4.sysctl_tcp_no_ssthresh_metrics_save) ? 487 0 : tcp_metric_get(tm, TCP_METRIC_SSTHRESH); 488 if (val) { 489 tp->snd_ssthresh = val; 490 if (tp->snd_ssthresh > tp->snd_cwnd_clamp) 491 tp->snd_ssthresh = tp->snd_cwnd_clamp; 492 } else { 493 /* ssthresh may have been reduced unnecessarily during. 494 * 3WHS. Restore it back to its initial default. 495 */ 496 tp->snd_ssthresh = TCP_INFINITE_SSTHRESH; 497 } 498 val = tcp_metric_get(tm, TCP_METRIC_REORDERING); 499 if (val && tp->reordering != val) 500 tp->reordering = val; 501 502 crtt = tcp_metric_get(tm, TCP_METRIC_RTT); 503 rcu_read_unlock(); 504 reset: 505 /* The initial RTT measurement from the SYN/SYN-ACK is not ideal 506 * to seed the RTO for later data packets because SYN packets are 507 * small. Use the per-dst cached values to seed the RTO but keep 508 * the RTT estimator variables intact (e.g., srtt, mdev, rttvar). 509 * Later the RTO will be updated immediately upon obtaining the first 510 * data RTT sample (tcp_rtt_estimator()). Hence the cached RTT only 511 * influences the first RTO but not later RTT estimation. 512 * 513 * But if RTT is not available from the SYN (due to retransmits or 514 * syn cookies) or the cache, force a conservative 3secs timeout. 515 * 516 * A bit of theory. RTT is time passed after "normal" sized packet 517 * is sent until it is ACKed. In normal circumstances sending small 518 * packets force peer to delay ACKs and calculation is correct too. 519 * The algorithm is adaptive and, provided we follow specs, it 520 * NEVER underestimate RTT. BUT! If peer tries to make some clever 521 * tricks sort of "quick acks" for time long enough to decrease RTT 522 * to low value, and then abruptly stops to do it and starts to delay 523 * ACKs, wait for troubles. 524 */ 525 if (crtt > tp->srtt_us) { 526 /* Set RTO like tcp_rtt_estimator(), but from cached RTT. */ 527 crtt /= 8 * USEC_PER_SEC / HZ; 528 inet_csk(sk)->icsk_rto = crtt + max(2 * crtt, tcp_rto_min(sk)); 529 } else if (tp->srtt_us == 0) { 530 /* RFC6298: 5.7 We've failed to get a valid RTT sample from 531 * 3WHS. This is most likely due to retransmission, 532 * including spurious one. Reset the RTO back to 3secs 533 * from the more aggressive 1sec to avoid more spurious 534 * retransmission. 535 */ 536 tp->rttvar_us = jiffies_to_usecs(TCP_TIMEOUT_FALLBACK); 537 tp->mdev_us = tp->mdev_max_us = tp->rttvar_us; 538 539 inet_csk(sk)->icsk_rto = TCP_TIMEOUT_FALLBACK; 540 } 541 } 542 543 bool tcp_peer_is_proven(struct request_sock *req, struct dst_entry *dst) 544 { 545 struct tcp_metrics_block *tm; 546 bool ret; 547 548 if (!dst) 549 return false; 550 551 rcu_read_lock(); 552 tm = __tcp_get_metrics_req(req, dst); 553 if (tm && tcp_metric_get(tm, TCP_METRIC_RTT)) 554 ret = true; 555 else 556 ret = false; 557 rcu_read_unlock(); 558 559 return ret; 560 } 561 562 void tcp_fastopen_cache_get(struct sock *sk, u16 *mss, 563 struct tcp_fastopen_cookie *cookie) 564 { 565 struct tcp_metrics_block *tm; 566 567 rcu_read_lock(); 568 tm = tcp_get_metrics(sk, __sk_dst_get(sk), false); 569 if (tm) { 570 struct tcp_fastopen_metrics *tfom = &tm->tcpm_fastopen; 571 unsigned int seq; 572 573 do { 574 seq = read_seqbegin(&fastopen_seqlock); 575 if (tfom->mss) 576 *mss = tfom->mss; 577 *cookie = tfom->cookie; 578 if (cookie->len <= 0 && tfom->try_exp == 1) 579 cookie->exp = true; 580 } while (read_seqretry(&fastopen_seqlock, seq)); 581 } 582 rcu_read_unlock(); 583 } 584 585 void tcp_fastopen_cache_set(struct sock *sk, u16 mss, 586 struct tcp_fastopen_cookie *cookie, bool syn_lost, 587 u16 try_exp) 588 { 589 struct dst_entry *dst = __sk_dst_get(sk); 590 struct tcp_metrics_block *tm; 591 592 if (!dst) 593 return; 594 rcu_read_lock(); 595 tm = tcp_get_metrics(sk, dst, true); 596 if (tm) { 597 struct tcp_fastopen_metrics *tfom = &tm->tcpm_fastopen; 598 599 write_seqlock_bh(&fastopen_seqlock); 600 if (mss) 601 tfom->mss = mss; 602 if (cookie && cookie->len > 0) 603 tfom->cookie = *cookie; 604 else if (try_exp > tfom->try_exp && 605 tfom->cookie.len <= 0 && !tfom->cookie.exp) 606 tfom->try_exp = try_exp; 607 if (syn_lost) { 608 ++tfom->syn_loss; 609 tfom->last_syn_loss = jiffies; 610 } else 611 tfom->syn_loss = 0; 612 write_sequnlock_bh(&fastopen_seqlock); 613 } 614 rcu_read_unlock(); 615 } 616 617 static struct genl_family tcp_metrics_nl_family; 618 619 static const struct nla_policy tcp_metrics_nl_policy[TCP_METRICS_ATTR_MAX + 1] = { 620 [TCP_METRICS_ATTR_ADDR_IPV4] = { .type = NLA_U32, }, 621 [TCP_METRICS_ATTR_ADDR_IPV6] = { .type = NLA_BINARY, 622 .len = sizeof(struct in6_addr), }, 623 /* Following attributes are not received for GET/DEL, 624 * we keep them for reference 625 */ 626 #if 0 627 [TCP_METRICS_ATTR_AGE] = { .type = NLA_MSECS, }, 628 [TCP_METRICS_ATTR_TW_TSVAL] = { .type = NLA_U32, }, 629 [TCP_METRICS_ATTR_TW_TS_STAMP] = { .type = NLA_S32, }, 630 [TCP_METRICS_ATTR_VALS] = { .type = NLA_NESTED, }, 631 [TCP_METRICS_ATTR_FOPEN_MSS] = { .type = NLA_U16, }, 632 [TCP_METRICS_ATTR_FOPEN_SYN_DROPS] = { .type = NLA_U16, }, 633 [TCP_METRICS_ATTR_FOPEN_SYN_DROP_TS] = { .type = NLA_MSECS, }, 634 [TCP_METRICS_ATTR_FOPEN_COOKIE] = { .type = NLA_BINARY, 635 .len = TCP_FASTOPEN_COOKIE_MAX, }, 636 #endif 637 }; 638 639 /* Add attributes, caller cancels its header on failure */ 640 static int tcp_metrics_fill_info(struct sk_buff *msg, 641 struct tcp_metrics_block *tm) 642 { 643 struct nlattr *nest; 644 int i; 645 646 switch (tm->tcpm_daddr.family) { 647 case AF_INET: 648 if (nla_put_in_addr(msg, TCP_METRICS_ATTR_ADDR_IPV4, 649 inetpeer_get_addr_v4(&tm->tcpm_daddr)) < 0) 650 goto nla_put_failure; 651 if (nla_put_in_addr(msg, TCP_METRICS_ATTR_SADDR_IPV4, 652 inetpeer_get_addr_v4(&tm->tcpm_saddr)) < 0) 653 goto nla_put_failure; 654 break; 655 case AF_INET6: 656 if (nla_put_in6_addr(msg, TCP_METRICS_ATTR_ADDR_IPV6, 657 inetpeer_get_addr_v6(&tm->tcpm_daddr)) < 0) 658 goto nla_put_failure; 659 if (nla_put_in6_addr(msg, TCP_METRICS_ATTR_SADDR_IPV6, 660 inetpeer_get_addr_v6(&tm->tcpm_saddr)) < 0) 661 goto nla_put_failure; 662 break; 663 default: 664 return -EAFNOSUPPORT; 665 } 666 667 if (nla_put_msecs(msg, TCP_METRICS_ATTR_AGE, 668 jiffies - READ_ONCE(tm->tcpm_stamp), 669 TCP_METRICS_ATTR_PAD) < 0) 670 goto nla_put_failure; 671 672 { 673 int n = 0; 674 675 nest = nla_nest_start_noflag(msg, TCP_METRICS_ATTR_VALS); 676 if (!nest) 677 goto nla_put_failure; 678 for (i = 0; i < TCP_METRIC_MAX_KERNEL + 1; i++) { 679 u32 val = tcp_metric_get(tm, i); 680 681 if (!val) 682 continue; 683 if (i == TCP_METRIC_RTT) { 684 if (nla_put_u32(msg, TCP_METRIC_RTT_US + 1, 685 val) < 0) 686 goto nla_put_failure; 687 n++; 688 val = max(val / 1000, 1U); 689 } 690 if (i == TCP_METRIC_RTTVAR) { 691 if (nla_put_u32(msg, TCP_METRIC_RTTVAR_US + 1, 692 val) < 0) 693 goto nla_put_failure; 694 n++; 695 val = max(val / 1000, 1U); 696 } 697 if (nla_put_u32(msg, i + 1, val) < 0) 698 goto nla_put_failure; 699 n++; 700 } 701 if (n) 702 nla_nest_end(msg, nest); 703 else 704 nla_nest_cancel(msg, nest); 705 } 706 707 { 708 struct tcp_fastopen_metrics tfom_copy[1], *tfom; 709 unsigned int seq; 710 711 do { 712 seq = read_seqbegin(&fastopen_seqlock); 713 tfom_copy[0] = tm->tcpm_fastopen; 714 } while (read_seqretry(&fastopen_seqlock, seq)); 715 716 tfom = tfom_copy; 717 if (tfom->mss && 718 nla_put_u16(msg, TCP_METRICS_ATTR_FOPEN_MSS, 719 tfom->mss) < 0) 720 goto nla_put_failure; 721 if (tfom->syn_loss && 722 (nla_put_u16(msg, TCP_METRICS_ATTR_FOPEN_SYN_DROPS, 723 tfom->syn_loss) < 0 || 724 nla_put_msecs(msg, TCP_METRICS_ATTR_FOPEN_SYN_DROP_TS, 725 jiffies - tfom->last_syn_loss, 726 TCP_METRICS_ATTR_PAD) < 0)) 727 goto nla_put_failure; 728 if (tfom->cookie.len > 0 && 729 nla_put(msg, TCP_METRICS_ATTR_FOPEN_COOKIE, 730 tfom->cookie.len, tfom->cookie.val) < 0) 731 goto nla_put_failure; 732 } 733 734 return 0; 735 736 nla_put_failure: 737 return -EMSGSIZE; 738 } 739 740 static int tcp_metrics_dump_info(struct sk_buff *skb, 741 struct netlink_callback *cb, 742 struct tcp_metrics_block *tm) 743 { 744 void *hdr; 745 746 hdr = genlmsg_put(skb, NETLINK_CB(cb->skb).portid, cb->nlh->nlmsg_seq, 747 &tcp_metrics_nl_family, NLM_F_MULTI, 748 TCP_METRICS_CMD_GET); 749 if (!hdr) 750 return -EMSGSIZE; 751 752 if (tcp_metrics_fill_info(skb, tm) < 0) 753 goto nla_put_failure; 754 755 genlmsg_end(skb, hdr); 756 return 0; 757 758 nla_put_failure: 759 genlmsg_cancel(skb, hdr); 760 return -EMSGSIZE; 761 } 762 763 static int tcp_metrics_nl_dump(struct sk_buff *skb, 764 struct netlink_callback *cb) 765 { 766 struct net *net = sock_net(skb->sk); 767 unsigned int max_rows = 1U << tcp_metrics_hash_log; 768 unsigned int row, s_row = cb->args[0]; 769 int s_col = cb->args[1], col = s_col; 770 771 for (row = s_row; row < max_rows; row++, s_col = 0) { 772 struct tcp_metrics_block *tm; 773 struct tcpm_hash_bucket *hb = tcp_metrics_hash + row; 774 775 rcu_read_lock(); 776 for (col = 0, tm = rcu_dereference(hb->chain); tm; 777 tm = rcu_dereference(tm->tcpm_next), col++) { 778 if (!net_eq(tm_net(tm), net)) 779 continue; 780 if (col < s_col) 781 continue; 782 if (tcp_metrics_dump_info(skb, cb, tm) < 0) { 783 rcu_read_unlock(); 784 goto done; 785 } 786 } 787 rcu_read_unlock(); 788 } 789 790 done: 791 cb->args[0] = row; 792 cb->args[1] = col; 793 return skb->len; 794 } 795 796 static int __parse_nl_addr(struct genl_info *info, struct inetpeer_addr *addr, 797 unsigned int *hash, int optional, int v4, int v6) 798 { 799 struct nlattr *a; 800 801 a = info->attrs[v4]; 802 if (a) { 803 inetpeer_set_addr_v4(addr, nla_get_in_addr(a)); 804 if (hash) 805 *hash = ipv4_addr_hash(inetpeer_get_addr_v4(addr)); 806 return 0; 807 } 808 a = info->attrs[v6]; 809 if (a) { 810 struct in6_addr in6; 811 812 if (nla_len(a) != sizeof(struct in6_addr)) 813 return -EINVAL; 814 in6 = nla_get_in6_addr(a); 815 inetpeer_set_addr_v6(addr, &in6); 816 if (hash) 817 *hash = ipv6_addr_hash(inetpeer_get_addr_v6(addr)); 818 return 0; 819 } 820 return optional ? 1 : -EAFNOSUPPORT; 821 } 822 823 static int parse_nl_addr(struct genl_info *info, struct inetpeer_addr *addr, 824 unsigned int *hash, int optional) 825 { 826 return __parse_nl_addr(info, addr, hash, optional, 827 TCP_METRICS_ATTR_ADDR_IPV4, 828 TCP_METRICS_ATTR_ADDR_IPV6); 829 } 830 831 static int parse_nl_saddr(struct genl_info *info, struct inetpeer_addr *addr) 832 { 833 return __parse_nl_addr(info, addr, NULL, 0, 834 TCP_METRICS_ATTR_SADDR_IPV4, 835 TCP_METRICS_ATTR_SADDR_IPV6); 836 } 837 838 static int tcp_metrics_nl_cmd_get(struct sk_buff *skb, struct genl_info *info) 839 { 840 struct tcp_metrics_block *tm; 841 struct inetpeer_addr saddr, daddr; 842 unsigned int hash; 843 struct sk_buff *msg; 844 struct net *net = genl_info_net(info); 845 void *reply; 846 int ret; 847 bool src = true; 848 849 ret = parse_nl_addr(info, &daddr, &hash, 0); 850 if (ret < 0) 851 return ret; 852 853 ret = parse_nl_saddr(info, &saddr); 854 if (ret < 0) 855 src = false; 856 857 msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL); 858 if (!msg) 859 return -ENOMEM; 860 861 reply = genlmsg_put_reply(msg, info, &tcp_metrics_nl_family, 0, 862 info->genlhdr->cmd); 863 if (!reply) 864 goto nla_put_failure; 865 866 hash ^= net_hash_mix(net); 867 hash = hash_32(hash, tcp_metrics_hash_log); 868 ret = -ESRCH; 869 rcu_read_lock(); 870 for (tm = rcu_dereference(tcp_metrics_hash[hash].chain); tm; 871 tm = rcu_dereference(tm->tcpm_next)) { 872 if (addr_same(&tm->tcpm_daddr, &daddr) && 873 (!src || addr_same(&tm->tcpm_saddr, &saddr)) && 874 net_eq(tm_net(tm), net)) { 875 ret = tcp_metrics_fill_info(msg, tm); 876 break; 877 } 878 } 879 rcu_read_unlock(); 880 if (ret < 0) 881 goto out_free; 882 883 genlmsg_end(msg, reply); 884 return genlmsg_reply(msg, info); 885 886 nla_put_failure: 887 ret = -EMSGSIZE; 888 889 out_free: 890 nlmsg_free(msg); 891 return ret; 892 } 893 894 static void tcp_metrics_flush_all(struct net *net) 895 { 896 unsigned int max_rows = 1U << tcp_metrics_hash_log; 897 struct tcpm_hash_bucket *hb = tcp_metrics_hash; 898 struct tcp_metrics_block *tm; 899 unsigned int row; 900 901 for (row = 0; row < max_rows; row++, hb++) { 902 struct tcp_metrics_block __rcu **pp; 903 bool match; 904 905 spin_lock_bh(&tcp_metrics_lock); 906 pp = &hb->chain; 907 for (tm = deref_locked(*pp); tm; tm = deref_locked(*pp)) { 908 match = net ? net_eq(tm_net(tm), net) : 909 !refcount_read(&tm_net(tm)->ns.count); 910 if (match) { 911 *pp = tm->tcpm_next; 912 kfree_rcu(tm, rcu_head); 913 } else { 914 pp = &tm->tcpm_next; 915 } 916 } 917 spin_unlock_bh(&tcp_metrics_lock); 918 } 919 } 920 921 static int tcp_metrics_nl_cmd_del(struct sk_buff *skb, struct genl_info *info) 922 { 923 struct tcpm_hash_bucket *hb; 924 struct tcp_metrics_block *tm; 925 struct tcp_metrics_block __rcu **pp; 926 struct inetpeer_addr saddr, daddr; 927 unsigned int hash; 928 struct net *net = genl_info_net(info); 929 int ret; 930 bool src = true, found = false; 931 932 ret = parse_nl_addr(info, &daddr, &hash, 1); 933 if (ret < 0) 934 return ret; 935 if (ret > 0) { 936 tcp_metrics_flush_all(net); 937 return 0; 938 } 939 ret = parse_nl_saddr(info, &saddr); 940 if (ret < 0) 941 src = false; 942 943 hash ^= net_hash_mix(net); 944 hash = hash_32(hash, tcp_metrics_hash_log); 945 hb = tcp_metrics_hash + hash; 946 pp = &hb->chain; 947 spin_lock_bh(&tcp_metrics_lock); 948 for (tm = deref_locked(*pp); tm; tm = deref_locked(*pp)) { 949 if (addr_same(&tm->tcpm_daddr, &daddr) && 950 (!src || addr_same(&tm->tcpm_saddr, &saddr)) && 951 net_eq(tm_net(tm), net)) { 952 *pp = tm->tcpm_next; 953 kfree_rcu(tm, rcu_head); 954 found = true; 955 } else { 956 pp = &tm->tcpm_next; 957 } 958 } 959 spin_unlock_bh(&tcp_metrics_lock); 960 if (!found) 961 return -ESRCH; 962 return 0; 963 } 964 965 static const struct genl_small_ops tcp_metrics_nl_ops[] = { 966 { 967 .cmd = TCP_METRICS_CMD_GET, 968 .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP, 969 .doit = tcp_metrics_nl_cmd_get, 970 .dumpit = tcp_metrics_nl_dump, 971 }, 972 { 973 .cmd = TCP_METRICS_CMD_DEL, 974 .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP, 975 .doit = tcp_metrics_nl_cmd_del, 976 .flags = GENL_ADMIN_PERM, 977 }, 978 }; 979 980 static struct genl_family tcp_metrics_nl_family __ro_after_init = { 981 .hdrsize = 0, 982 .name = TCP_METRICS_GENL_NAME, 983 .version = TCP_METRICS_GENL_VERSION, 984 .maxattr = TCP_METRICS_ATTR_MAX, 985 .policy = tcp_metrics_nl_policy, 986 .netnsok = true, 987 .module = THIS_MODULE, 988 .small_ops = tcp_metrics_nl_ops, 989 .n_small_ops = ARRAY_SIZE(tcp_metrics_nl_ops), 990 .resv_start_op = TCP_METRICS_CMD_DEL + 1, 991 }; 992 993 static unsigned int tcpmhash_entries __initdata; 994 static int __init set_tcpmhash_entries(char *str) 995 { 996 ssize_t ret; 997 998 if (!str) 999 return 0; 1000 1001 ret = kstrtouint(str, 0, &tcpmhash_entries); 1002 if (ret) 1003 return 0; 1004 1005 return 1; 1006 } 1007 __setup("tcpmhash_entries=", set_tcpmhash_entries); 1008 1009 static void __init tcp_metrics_hash_alloc(void) 1010 { 1011 unsigned int slots = tcpmhash_entries; 1012 size_t size; 1013 1014 if (!slots) { 1015 if (totalram_pages() >= 128 * 1024) 1016 slots = 16 * 1024; 1017 else 1018 slots = 8 * 1024; 1019 } 1020 1021 tcp_metrics_hash_log = order_base_2(slots); 1022 size = sizeof(struct tcpm_hash_bucket) << tcp_metrics_hash_log; 1023 1024 tcp_metrics_hash = kvzalloc(size, GFP_KERNEL); 1025 if (!tcp_metrics_hash) 1026 panic("Could not allocate the tcp_metrics hash table\n"); 1027 } 1028 1029 static void __net_exit tcp_net_metrics_exit_batch(struct list_head *net_exit_list) 1030 { 1031 tcp_metrics_flush_all(NULL); 1032 } 1033 1034 static __net_initdata struct pernet_operations tcp_net_metrics_ops = { 1035 .exit_batch = tcp_net_metrics_exit_batch, 1036 }; 1037 1038 void __init tcp_metrics_init(void) 1039 { 1040 int ret; 1041 1042 tcp_metrics_hash_alloc(); 1043 1044 ret = register_pernet_subsys(&tcp_net_metrics_ops); 1045 if (ret < 0) 1046 panic("Could not register tcp_net_metrics_ops\n"); 1047 1048 ret = genl_register_family(&tcp_metrics_nl_family); 1049 if (ret < 0) 1050 panic("Could not register tcp_metrics generic netlink\n"); 1051 } 1052