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 int sysctl_tcp_nometrics_save __read_mostly; 25 26 static struct tcp_metrics_block *__tcp_get_metrics(const struct inetpeer_addr *saddr, 27 const struct inetpeer_addr *daddr, 28 struct net *net, unsigned int hash); 29 30 struct tcp_fastopen_metrics { 31 u16 mss; 32 u16 syn_loss:10, /* Recurring Fast Open SYN losses */ 33 try_exp:2; /* Request w/ exp. option (once) */ 34 unsigned long last_syn_loss; /* Last Fast Open SYN loss */ 35 struct tcp_fastopen_cookie cookie; 36 }; 37 38 /* TCP_METRIC_MAX includes 2 extra fields for userspace compatibility 39 * Kernel only stores RTT and RTTVAR in usec resolution 40 */ 41 #define TCP_METRIC_MAX_KERNEL (TCP_METRIC_MAX - 2) 42 43 struct tcp_metrics_block { 44 struct tcp_metrics_block __rcu *tcpm_next; 45 possible_net_t tcpm_net; 46 struct inetpeer_addr tcpm_saddr; 47 struct inetpeer_addr tcpm_daddr; 48 unsigned long tcpm_stamp; 49 u32 tcpm_lock; 50 u32 tcpm_vals[TCP_METRIC_MAX_KERNEL + 1]; 51 struct tcp_fastopen_metrics tcpm_fastopen; 52 53 struct rcu_head rcu_head; 54 }; 55 56 static inline struct net *tm_net(struct tcp_metrics_block *tm) 57 { 58 return read_pnet(&tm->tcpm_net); 59 } 60 61 static bool tcp_metric_locked(struct tcp_metrics_block *tm, 62 enum tcp_metric_index idx) 63 { 64 return tm->tcpm_lock & (1 << idx); 65 } 66 67 static u32 tcp_metric_get(struct tcp_metrics_block *tm, 68 enum tcp_metric_index idx) 69 { 70 return tm->tcpm_vals[idx]; 71 } 72 73 static void tcp_metric_set(struct tcp_metrics_block *tm, 74 enum tcp_metric_index idx, 75 u32 val) 76 { 77 tm->tcpm_vals[idx] = val; 78 } 79 80 static bool addr_same(const struct inetpeer_addr *a, 81 const struct inetpeer_addr *b) 82 { 83 return inetpeer_addr_cmp(a, b) == 0; 84 } 85 86 struct tcpm_hash_bucket { 87 struct tcp_metrics_block __rcu *chain; 88 }; 89 90 static struct tcpm_hash_bucket *tcp_metrics_hash __read_mostly; 91 static unsigned int tcp_metrics_hash_log __read_mostly; 92 93 static DEFINE_SPINLOCK(tcp_metrics_lock); 94 95 static void tcpm_suck_dst(struct tcp_metrics_block *tm, 96 const struct dst_entry *dst, 97 bool fastopen_clear) 98 { 99 u32 msval; 100 u32 val; 101 102 tm->tcpm_stamp = jiffies; 103 104 val = 0; 105 if (dst_metric_locked(dst, RTAX_RTT)) 106 val |= 1 << TCP_METRIC_RTT; 107 if (dst_metric_locked(dst, RTAX_RTTVAR)) 108 val |= 1 << TCP_METRIC_RTTVAR; 109 if (dst_metric_locked(dst, RTAX_SSTHRESH)) 110 val |= 1 << TCP_METRIC_SSTHRESH; 111 if (dst_metric_locked(dst, RTAX_CWND)) 112 val |= 1 << TCP_METRIC_CWND; 113 if (dst_metric_locked(dst, RTAX_REORDERING)) 114 val |= 1 << TCP_METRIC_REORDERING; 115 tm->tcpm_lock = val; 116 117 msval = dst_metric_raw(dst, RTAX_RTT); 118 tm->tcpm_vals[TCP_METRIC_RTT] = msval * USEC_PER_MSEC; 119 120 msval = dst_metric_raw(dst, RTAX_RTTVAR); 121 tm->tcpm_vals[TCP_METRIC_RTTVAR] = msval * USEC_PER_MSEC; 122 tm->tcpm_vals[TCP_METRIC_SSTHRESH] = dst_metric_raw(dst, RTAX_SSTHRESH); 123 tm->tcpm_vals[TCP_METRIC_CWND] = dst_metric_raw(dst, RTAX_CWND); 124 tm->tcpm_vals[TCP_METRIC_REORDERING] = dst_metric_raw(dst, RTAX_REORDERING); 125 if (fastopen_clear) { 126 tm->tcpm_fastopen.mss = 0; 127 tm->tcpm_fastopen.syn_loss = 0; 128 tm->tcpm_fastopen.try_exp = 0; 129 tm->tcpm_fastopen.cookie.exp = false; 130 tm->tcpm_fastopen.cookie.len = 0; 131 } 132 } 133 134 #define TCP_METRICS_TIMEOUT (60 * 60 * HZ) 135 136 static void tcpm_check_stamp(struct tcp_metrics_block *tm, struct dst_entry *dst) 137 { 138 if (tm && unlikely(time_after(jiffies, tm->tcpm_stamp + TCP_METRICS_TIMEOUT))) 139 tcpm_suck_dst(tm, dst, false); 140 } 141 142 #define TCP_METRICS_RECLAIM_DEPTH 5 143 #define TCP_METRICS_RECLAIM_PTR (struct tcp_metrics_block *) 0x1UL 144 145 #define deref_locked(p) \ 146 rcu_dereference_protected(p, lockdep_is_held(&tcp_metrics_lock)) 147 148 static struct tcp_metrics_block *tcpm_new(struct dst_entry *dst, 149 struct inetpeer_addr *saddr, 150 struct inetpeer_addr *daddr, 151 unsigned int hash) 152 { 153 struct tcp_metrics_block *tm; 154 struct net *net; 155 bool reclaim = false; 156 157 spin_lock_bh(&tcp_metrics_lock); 158 net = dev_net(dst->dev); 159 160 /* While waiting for the spin-lock the cache might have been populated 161 * with this entry and so we have to check again. 162 */ 163 tm = __tcp_get_metrics(saddr, daddr, net, hash); 164 if (tm == TCP_METRICS_RECLAIM_PTR) { 165 reclaim = true; 166 tm = NULL; 167 } 168 if (tm) { 169 tcpm_check_stamp(tm, dst); 170 goto out_unlock; 171 } 172 173 if (unlikely(reclaim)) { 174 struct tcp_metrics_block *oldest; 175 176 oldest = deref_locked(tcp_metrics_hash[hash].chain); 177 for (tm = deref_locked(oldest->tcpm_next); tm; 178 tm = deref_locked(tm->tcpm_next)) { 179 if (time_before(tm->tcpm_stamp, oldest->tcpm_stamp)) 180 oldest = tm; 181 } 182 tm = oldest; 183 } else { 184 tm = kmalloc(sizeof(*tm), GFP_ATOMIC); 185 if (!tm) 186 goto out_unlock; 187 } 188 write_pnet(&tm->tcpm_net, net); 189 tm->tcpm_saddr = *saddr; 190 tm->tcpm_daddr = *daddr; 191 192 tcpm_suck_dst(tm, dst, true); 193 194 if (likely(!reclaim)) { 195 tm->tcpm_next = tcp_metrics_hash[hash].chain; 196 rcu_assign_pointer(tcp_metrics_hash[hash].chain, tm); 197 } 198 199 out_unlock: 200 spin_unlock_bh(&tcp_metrics_lock); 201 return tm; 202 } 203 204 static struct tcp_metrics_block *tcp_get_encode(struct tcp_metrics_block *tm, int depth) 205 { 206 if (tm) 207 return tm; 208 if (depth > TCP_METRICS_RECLAIM_DEPTH) 209 return TCP_METRICS_RECLAIM_PTR; 210 return NULL; 211 } 212 213 static struct tcp_metrics_block *__tcp_get_metrics(const struct inetpeer_addr *saddr, 214 const struct inetpeer_addr *daddr, 215 struct net *net, unsigned int hash) 216 { 217 struct tcp_metrics_block *tm; 218 int depth = 0; 219 220 for (tm = rcu_dereference(tcp_metrics_hash[hash].chain); tm; 221 tm = rcu_dereference(tm->tcpm_next)) { 222 if (addr_same(&tm->tcpm_saddr, saddr) && 223 addr_same(&tm->tcpm_daddr, daddr) && 224 net_eq(tm_net(tm), net)) 225 break; 226 depth++; 227 } 228 return tcp_get_encode(tm, depth); 229 } 230 231 static struct tcp_metrics_block *__tcp_get_metrics_req(struct request_sock *req, 232 struct dst_entry *dst) 233 { 234 struct tcp_metrics_block *tm; 235 struct inetpeer_addr saddr, daddr; 236 unsigned int hash; 237 struct net *net; 238 239 saddr.family = req->rsk_ops->family; 240 daddr.family = req->rsk_ops->family; 241 switch (daddr.family) { 242 case AF_INET: 243 inetpeer_set_addr_v4(&saddr, inet_rsk(req)->ir_loc_addr); 244 inetpeer_set_addr_v4(&daddr, inet_rsk(req)->ir_rmt_addr); 245 hash = ipv4_addr_hash(inet_rsk(req)->ir_rmt_addr); 246 break; 247 #if IS_ENABLED(CONFIG_IPV6) 248 case AF_INET6: 249 inetpeer_set_addr_v6(&saddr, &inet_rsk(req)->ir_v6_loc_addr); 250 inetpeer_set_addr_v6(&daddr, &inet_rsk(req)->ir_v6_rmt_addr); 251 hash = ipv6_addr_hash(&inet_rsk(req)->ir_v6_rmt_addr); 252 break; 253 #endif 254 default: 255 return NULL; 256 } 257 258 net = dev_net(dst->dev); 259 hash ^= net_hash_mix(net); 260 hash = hash_32(hash, tcp_metrics_hash_log); 261 262 for (tm = rcu_dereference(tcp_metrics_hash[hash].chain); tm; 263 tm = rcu_dereference(tm->tcpm_next)) { 264 if (addr_same(&tm->tcpm_saddr, &saddr) && 265 addr_same(&tm->tcpm_daddr, &daddr) && 266 net_eq(tm_net(tm), net)) 267 break; 268 } 269 tcpm_check_stamp(tm, dst); 270 return tm; 271 } 272 273 static struct tcp_metrics_block *tcp_get_metrics(struct sock *sk, 274 struct dst_entry *dst, 275 bool create) 276 { 277 struct tcp_metrics_block *tm; 278 struct inetpeer_addr saddr, daddr; 279 unsigned int hash; 280 struct net *net; 281 282 if (sk->sk_family == AF_INET) { 283 inetpeer_set_addr_v4(&saddr, inet_sk(sk)->inet_saddr); 284 inetpeer_set_addr_v4(&daddr, inet_sk(sk)->inet_daddr); 285 hash = ipv4_addr_hash(inet_sk(sk)->inet_daddr); 286 } 287 #if IS_ENABLED(CONFIG_IPV6) 288 else if (sk->sk_family == AF_INET6) { 289 if (ipv6_addr_v4mapped(&sk->sk_v6_daddr)) { 290 inetpeer_set_addr_v4(&saddr, inet_sk(sk)->inet_saddr); 291 inetpeer_set_addr_v4(&daddr, inet_sk(sk)->inet_daddr); 292 hash = ipv4_addr_hash(inet_sk(sk)->inet_daddr); 293 } else { 294 inetpeer_set_addr_v6(&saddr, &sk->sk_v6_rcv_saddr); 295 inetpeer_set_addr_v6(&daddr, &sk->sk_v6_daddr); 296 hash = ipv6_addr_hash(&sk->sk_v6_daddr); 297 } 298 } 299 #endif 300 else 301 return NULL; 302 303 net = dev_net(dst->dev); 304 hash ^= net_hash_mix(net); 305 hash = hash_32(hash, tcp_metrics_hash_log); 306 307 tm = __tcp_get_metrics(&saddr, &daddr, net, hash); 308 if (tm == TCP_METRICS_RECLAIM_PTR) 309 tm = NULL; 310 if (!tm && create) 311 tm = tcpm_new(dst, &saddr, &daddr, hash); 312 else 313 tcpm_check_stamp(tm, dst); 314 315 return tm; 316 } 317 318 /* Save metrics learned by this TCP session. This function is called 319 * only, when TCP finishes successfully i.e. when it enters TIME-WAIT 320 * or goes from LAST-ACK to CLOSE. 321 */ 322 void tcp_update_metrics(struct sock *sk) 323 { 324 const struct inet_connection_sock *icsk = inet_csk(sk); 325 struct dst_entry *dst = __sk_dst_get(sk); 326 struct tcp_sock *tp = tcp_sk(sk); 327 struct net *net = sock_net(sk); 328 struct tcp_metrics_block *tm; 329 unsigned long rtt; 330 u32 val; 331 int m; 332 333 sk_dst_confirm(sk); 334 if (sysctl_tcp_nometrics_save || !dst) 335 return; 336 337 rcu_read_lock(); 338 if (icsk->icsk_backoff || !tp->srtt_us) { 339 /* This session failed to estimate rtt. Why? 340 * Probably, no packets returned in time. Reset our 341 * results. 342 */ 343 tm = tcp_get_metrics(sk, dst, false); 344 if (tm && !tcp_metric_locked(tm, TCP_METRIC_RTT)) 345 tcp_metric_set(tm, TCP_METRIC_RTT, 0); 346 goto out_unlock; 347 } else 348 tm = tcp_get_metrics(sk, dst, true); 349 350 if (!tm) 351 goto out_unlock; 352 353 rtt = tcp_metric_get(tm, TCP_METRIC_RTT); 354 m = rtt - tp->srtt_us; 355 356 /* If newly calculated rtt larger than stored one, store new 357 * one. Otherwise, use EWMA. Remember, rtt overestimation is 358 * always better than underestimation. 359 */ 360 if (!tcp_metric_locked(tm, TCP_METRIC_RTT)) { 361 if (m <= 0) 362 rtt = tp->srtt_us; 363 else 364 rtt -= (m >> 3); 365 tcp_metric_set(tm, TCP_METRIC_RTT, rtt); 366 } 367 368 if (!tcp_metric_locked(tm, TCP_METRIC_RTTVAR)) { 369 unsigned long var; 370 371 if (m < 0) 372 m = -m; 373 374 /* Scale deviation to rttvar fixed point */ 375 m >>= 1; 376 if (m < tp->mdev_us) 377 m = tp->mdev_us; 378 379 var = tcp_metric_get(tm, TCP_METRIC_RTTVAR); 380 if (m >= var) 381 var = m; 382 else 383 var -= (var - m) >> 2; 384 385 tcp_metric_set(tm, TCP_METRIC_RTTVAR, var); 386 } 387 388 if (tcp_in_initial_slowstart(tp)) { 389 /* Slow start still did not finish. */ 390 if (!tcp_metric_locked(tm, TCP_METRIC_SSTHRESH)) { 391 val = tcp_metric_get(tm, TCP_METRIC_SSTHRESH); 392 if (val && (tp->snd_cwnd >> 1) > val) 393 tcp_metric_set(tm, TCP_METRIC_SSTHRESH, 394 tp->snd_cwnd >> 1); 395 } 396 if (!tcp_metric_locked(tm, TCP_METRIC_CWND)) { 397 val = tcp_metric_get(tm, TCP_METRIC_CWND); 398 if (tp->snd_cwnd > val) 399 tcp_metric_set(tm, TCP_METRIC_CWND, 400 tp->snd_cwnd); 401 } 402 } else if (!tcp_in_slow_start(tp) && 403 icsk->icsk_ca_state == TCP_CA_Open) { 404 /* Cong. avoidance phase, cwnd is reliable. */ 405 if (!tcp_metric_locked(tm, TCP_METRIC_SSTHRESH)) 406 tcp_metric_set(tm, TCP_METRIC_SSTHRESH, 407 max(tp->snd_cwnd >> 1, tp->snd_ssthresh)); 408 if (!tcp_metric_locked(tm, TCP_METRIC_CWND)) { 409 val = tcp_metric_get(tm, TCP_METRIC_CWND); 410 tcp_metric_set(tm, TCP_METRIC_CWND, (val + tp->snd_cwnd) >> 1); 411 } 412 } else { 413 /* Else slow start did not finish, cwnd is non-sense, 414 * ssthresh may be also invalid. 415 */ 416 if (!tcp_metric_locked(tm, TCP_METRIC_CWND)) { 417 val = tcp_metric_get(tm, TCP_METRIC_CWND); 418 tcp_metric_set(tm, TCP_METRIC_CWND, 419 (val + tp->snd_ssthresh) >> 1); 420 } 421 if (!tcp_metric_locked(tm, TCP_METRIC_SSTHRESH)) { 422 val = tcp_metric_get(tm, TCP_METRIC_SSTHRESH); 423 if (val && tp->snd_ssthresh > val) 424 tcp_metric_set(tm, TCP_METRIC_SSTHRESH, 425 tp->snd_ssthresh); 426 } 427 if (!tcp_metric_locked(tm, TCP_METRIC_REORDERING)) { 428 val = tcp_metric_get(tm, TCP_METRIC_REORDERING); 429 if (val < tp->reordering && 430 tp->reordering != net->ipv4.sysctl_tcp_reordering) 431 tcp_metric_set(tm, TCP_METRIC_REORDERING, 432 tp->reordering); 433 } 434 } 435 tm->tcpm_stamp = jiffies; 436 out_unlock: 437 rcu_read_unlock(); 438 } 439 440 /* Initialize metrics on socket. */ 441 442 void tcp_init_metrics(struct sock *sk) 443 { 444 struct dst_entry *dst = __sk_dst_get(sk); 445 struct tcp_sock *tp = tcp_sk(sk); 446 struct tcp_metrics_block *tm; 447 u32 val, crtt = 0; /* cached RTT scaled by 8 */ 448 449 sk_dst_confirm(sk); 450 if (!dst) 451 goto reset; 452 453 rcu_read_lock(); 454 tm = tcp_get_metrics(sk, dst, true); 455 if (!tm) { 456 rcu_read_unlock(); 457 goto reset; 458 } 459 460 if (tcp_metric_locked(tm, TCP_METRIC_CWND)) 461 tp->snd_cwnd_clamp = tcp_metric_get(tm, TCP_METRIC_CWND); 462 463 val = tcp_metric_get(tm, TCP_METRIC_SSTHRESH); 464 if (val) { 465 tp->snd_ssthresh = val; 466 if (tp->snd_ssthresh > tp->snd_cwnd_clamp) 467 tp->snd_ssthresh = tp->snd_cwnd_clamp; 468 } else { 469 /* ssthresh may have been reduced unnecessarily during. 470 * 3WHS. Restore it back to its initial default. 471 */ 472 tp->snd_ssthresh = TCP_INFINITE_SSTHRESH; 473 } 474 val = tcp_metric_get(tm, TCP_METRIC_REORDERING); 475 if (val && tp->reordering != val) { 476 tcp_disable_fack(tp); 477 tp->reordering = val; 478 } 479 480 crtt = tcp_metric_get(tm, TCP_METRIC_RTT); 481 rcu_read_unlock(); 482 reset: 483 /* The initial RTT measurement from the SYN/SYN-ACK is not ideal 484 * to seed the RTO for later data packets because SYN packets are 485 * small. Use the per-dst cached values to seed the RTO but keep 486 * the RTT estimator variables intact (e.g., srtt, mdev, rttvar). 487 * Later the RTO will be updated immediately upon obtaining the first 488 * data RTT sample (tcp_rtt_estimator()). Hence the cached RTT only 489 * influences the first RTO but not later RTT estimation. 490 * 491 * But if RTT is not available from the SYN (due to retransmits or 492 * syn cookies) or the cache, force a conservative 3secs timeout. 493 * 494 * A bit of theory. RTT is time passed after "normal" sized packet 495 * is sent until it is ACKed. In normal circumstances sending small 496 * packets force peer to delay ACKs and calculation is correct too. 497 * The algorithm is adaptive and, provided we follow specs, it 498 * NEVER underestimate RTT. BUT! If peer tries to make some clever 499 * tricks sort of "quick acks" for time long enough to decrease RTT 500 * to low value, and then abruptly stops to do it and starts to delay 501 * ACKs, wait for troubles. 502 */ 503 if (crtt > tp->srtt_us) { 504 /* Set RTO like tcp_rtt_estimator(), but from cached RTT. */ 505 crtt /= 8 * USEC_PER_SEC / HZ; 506 inet_csk(sk)->icsk_rto = crtt + max(2 * crtt, tcp_rto_min(sk)); 507 } else if (tp->srtt_us == 0) { 508 /* RFC6298: 5.7 We've failed to get a valid RTT sample from 509 * 3WHS. This is most likely due to retransmission, 510 * including spurious one. Reset the RTO back to 3secs 511 * from the more aggressive 1sec to avoid more spurious 512 * retransmission. 513 */ 514 tp->rttvar_us = jiffies_to_usecs(TCP_TIMEOUT_FALLBACK); 515 tp->mdev_us = tp->mdev_max_us = tp->rttvar_us; 516 517 inet_csk(sk)->icsk_rto = TCP_TIMEOUT_FALLBACK; 518 } 519 /* Cut cwnd down to 1 per RFC5681 if SYN or SYN-ACK has been 520 * retransmitted. In light of RFC6298 more aggressive 1sec 521 * initRTO, we only reset cwnd when more than 1 SYN/SYN-ACK 522 * retransmission has occurred. 523 */ 524 if (tp->total_retrans > 1) 525 tp->snd_cwnd = 1; 526 else 527 tp->snd_cwnd = tcp_init_cwnd(tp, dst); 528 tp->snd_cwnd_stamp = tcp_jiffies32; 529 } 530 531 bool tcp_peer_is_proven(struct request_sock *req, struct dst_entry *dst) 532 { 533 struct tcp_metrics_block *tm; 534 bool ret; 535 536 if (!dst) 537 return false; 538 539 rcu_read_lock(); 540 tm = __tcp_get_metrics_req(req, dst); 541 if (tm && tcp_metric_get(tm, TCP_METRIC_RTT)) 542 ret = true; 543 else 544 ret = false; 545 rcu_read_unlock(); 546 547 return ret; 548 } 549 550 static DEFINE_SEQLOCK(fastopen_seqlock); 551 552 void tcp_fastopen_cache_get(struct sock *sk, u16 *mss, 553 struct tcp_fastopen_cookie *cookie, 554 int *syn_loss, unsigned long *last_syn_loss) 555 { 556 struct tcp_metrics_block *tm; 557 558 rcu_read_lock(); 559 tm = tcp_get_metrics(sk, __sk_dst_get(sk), false); 560 if (tm) { 561 struct tcp_fastopen_metrics *tfom = &tm->tcpm_fastopen; 562 unsigned int seq; 563 564 do { 565 seq = read_seqbegin(&fastopen_seqlock); 566 if (tfom->mss) 567 *mss = tfom->mss; 568 *cookie = tfom->cookie; 569 if (cookie->len <= 0 && tfom->try_exp == 1) 570 cookie->exp = true; 571 *syn_loss = tfom->syn_loss; 572 *last_syn_loss = *syn_loss ? tfom->last_syn_loss : 0; 573 } while (read_seqretry(&fastopen_seqlock, seq)); 574 } 575 rcu_read_unlock(); 576 } 577 578 void tcp_fastopen_cache_set(struct sock *sk, u16 mss, 579 struct tcp_fastopen_cookie *cookie, bool syn_lost, 580 u16 try_exp) 581 { 582 struct dst_entry *dst = __sk_dst_get(sk); 583 struct tcp_metrics_block *tm; 584 585 if (!dst) 586 return; 587 rcu_read_lock(); 588 tm = tcp_get_metrics(sk, dst, true); 589 if (tm) { 590 struct tcp_fastopen_metrics *tfom = &tm->tcpm_fastopen; 591 592 write_seqlock_bh(&fastopen_seqlock); 593 if (mss) 594 tfom->mss = mss; 595 if (cookie && cookie->len > 0) 596 tfom->cookie = *cookie; 597 else if (try_exp > tfom->try_exp && 598 tfom->cookie.len <= 0 && !tfom->cookie.exp) 599 tfom->try_exp = try_exp; 600 if (syn_lost) { 601 ++tfom->syn_loss; 602 tfom->last_syn_loss = jiffies; 603 } else 604 tfom->syn_loss = 0; 605 write_sequnlock_bh(&fastopen_seqlock); 606 } 607 rcu_read_unlock(); 608 } 609 610 static struct genl_family tcp_metrics_nl_family; 611 612 static const struct nla_policy tcp_metrics_nl_policy[TCP_METRICS_ATTR_MAX + 1] = { 613 [TCP_METRICS_ATTR_ADDR_IPV4] = { .type = NLA_U32, }, 614 [TCP_METRICS_ATTR_ADDR_IPV6] = { .type = NLA_BINARY, 615 .len = sizeof(struct in6_addr), }, 616 /* Following attributes are not received for GET/DEL, 617 * we keep them for reference 618 */ 619 #if 0 620 [TCP_METRICS_ATTR_AGE] = { .type = NLA_MSECS, }, 621 [TCP_METRICS_ATTR_TW_TSVAL] = { .type = NLA_U32, }, 622 [TCP_METRICS_ATTR_TW_TS_STAMP] = { .type = NLA_S32, }, 623 [TCP_METRICS_ATTR_VALS] = { .type = NLA_NESTED, }, 624 [TCP_METRICS_ATTR_FOPEN_MSS] = { .type = NLA_U16, }, 625 [TCP_METRICS_ATTR_FOPEN_SYN_DROPS] = { .type = NLA_U16, }, 626 [TCP_METRICS_ATTR_FOPEN_SYN_DROP_TS] = { .type = NLA_MSECS, }, 627 [TCP_METRICS_ATTR_FOPEN_COOKIE] = { .type = NLA_BINARY, 628 .len = TCP_FASTOPEN_COOKIE_MAX, }, 629 #endif 630 }; 631 632 /* Add attributes, caller cancels its header on failure */ 633 static int tcp_metrics_fill_info(struct sk_buff *msg, 634 struct tcp_metrics_block *tm) 635 { 636 struct nlattr *nest; 637 int i; 638 639 switch (tm->tcpm_daddr.family) { 640 case AF_INET: 641 if (nla_put_in_addr(msg, TCP_METRICS_ATTR_ADDR_IPV4, 642 inetpeer_get_addr_v4(&tm->tcpm_daddr)) < 0) 643 goto nla_put_failure; 644 if (nla_put_in_addr(msg, TCP_METRICS_ATTR_SADDR_IPV4, 645 inetpeer_get_addr_v4(&tm->tcpm_saddr)) < 0) 646 goto nla_put_failure; 647 break; 648 case AF_INET6: 649 if (nla_put_in6_addr(msg, TCP_METRICS_ATTR_ADDR_IPV6, 650 inetpeer_get_addr_v6(&tm->tcpm_daddr)) < 0) 651 goto nla_put_failure; 652 if (nla_put_in6_addr(msg, TCP_METRICS_ATTR_SADDR_IPV6, 653 inetpeer_get_addr_v6(&tm->tcpm_saddr)) < 0) 654 goto nla_put_failure; 655 break; 656 default: 657 return -EAFNOSUPPORT; 658 } 659 660 if (nla_put_msecs(msg, TCP_METRICS_ATTR_AGE, 661 jiffies - tm->tcpm_stamp, 662 TCP_METRICS_ATTR_PAD) < 0) 663 goto nla_put_failure; 664 665 { 666 int n = 0; 667 668 nest = nla_nest_start(msg, TCP_METRICS_ATTR_VALS); 669 if (!nest) 670 goto nla_put_failure; 671 for (i = 0; i < TCP_METRIC_MAX_KERNEL + 1; i++) { 672 u32 val = tm->tcpm_vals[i]; 673 674 if (!val) 675 continue; 676 if (i == TCP_METRIC_RTT) { 677 if (nla_put_u32(msg, TCP_METRIC_RTT_US + 1, 678 val) < 0) 679 goto nla_put_failure; 680 n++; 681 val = max(val / 1000, 1U); 682 } 683 if (i == TCP_METRIC_RTTVAR) { 684 if (nla_put_u32(msg, TCP_METRIC_RTTVAR_US + 1, 685 val) < 0) 686 goto nla_put_failure; 687 n++; 688 val = max(val / 1000, 1U); 689 } 690 if (nla_put_u32(msg, i + 1, val) < 0) 691 goto nla_put_failure; 692 n++; 693 } 694 if (n) 695 nla_nest_end(msg, nest); 696 else 697 nla_nest_cancel(msg, nest); 698 } 699 700 { 701 struct tcp_fastopen_metrics tfom_copy[1], *tfom; 702 unsigned int seq; 703 704 do { 705 seq = read_seqbegin(&fastopen_seqlock); 706 tfom_copy[0] = tm->tcpm_fastopen; 707 } while (read_seqretry(&fastopen_seqlock, seq)); 708 709 tfom = tfom_copy; 710 if (tfom->mss && 711 nla_put_u16(msg, TCP_METRICS_ATTR_FOPEN_MSS, 712 tfom->mss) < 0) 713 goto nla_put_failure; 714 if (tfom->syn_loss && 715 (nla_put_u16(msg, TCP_METRICS_ATTR_FOPEN_SYN_DROPS, 716 tfom->syn_loss) < 0 || 717 nla_put_msecs(msg, TCP_METRICS_ATTR_FOPEN_SYN_DROP_TS, 718 jiffies - tfom->last_syn_loss, 719 TCP_METRICS_ATTR_PAD) < 0)) 720 goto nla_put_failure; 721 if (tfom->cookie.len > 0 && 722 nla_put(msg, TCP_METRICS_ATTR_FOPEN_COOKIE, 723 tfom->cookie.len, tfom->cookie.val) < 0) 724 goto nla_put_failure; 725 } 726 727 return 0; 728 729 nla_put_failure: 730 return -EMSGSIZE; 731 } 732 733 static int tcp_metrics_dump_info(struct sk_buff *skb, 734 struct netlink_callback *cb, 735 struct tcp_metrics_block *tm) 736 { 737 void *hdr; 738 739 hdr = genlmsg_put(skb, NETLINK_CB(cb->skb).portid, cb->nlh->nlmsg_seq, 740 &tcp_metrics_nl_family, NLM_F_MULTI, 741 TCP_METRICS_CMD_GET); 742 if (!hdr) 743 return -EMSGSIZE; 744 745 if (tcp_metrics_fill_info(skb, tm) < 0) 746 goto nla_put_failure; 747 748 genlmsg_end(skb, hdr); 749 return 0; 750 751 nla_put_failure: 752 genlmsg_cancel(skb, hdr); 753 return -EMSGSIZE; 754 } 755 756 static int tcp_metrics_nl_dump(struct sk_buff *skb, 757 struct netlink_callback *cb) 758 { 759 struct net *net = sock_net(skb->sk); 760 unsigned int max_rows = 1U << tcp_metrics_hash_log; 761 unsigned int row, s_row = cb->args[0]; 762 int s_col = cb->args[1], col = s_col; 763 764 for (row = s_row; row < max_rows; row++, s_col = 0) { 765 struct tcp_metrics_block *tm; 766 struct tcpm_hash_bucket *hb = tcp_metrics_hash + row; 767 768 rcu_read_lock(); 769 for (col = 0, tm = rcu_dereference(hb->chain); tm; 770 tm = rcu_dereference(tm->tcpm_next), col++) { 771 if (!net_eq(tm_net(tm), net)) 772 continue; 773 if (col < s_col) 774 continue; 775 if (tcp_metrics_dump_info(skb, cb, tm) < 0) { 776 rcu_read_unlock(); 777 goto done; 778 } 779 } 780 rcu_read_unlock(); 781 } 782 783 done: 784 cb->args[0] = row; 785 cb->args[1] = col; 786 return skb->len; 787 } 788 789 static int __parse_nl_addr(struct genl_info *info, struct inetpeer_addr *addr, 790 unsigned int *hash, int optional, int v4, int v6) 791 { 792 struct nlattr *a; 793 794 a = info->attrs[v4]; 795 if (a) { 796 inetpeer_set_addr_v4(addr, nla_get_in_addr(a)); 797 if (hash) 798 *hash = ipv4_addr_hash(inetpeer_get_addr_v4(addr)); 799 return 0; 800 } 801 a = info->attrs[v6]; 802 if (a) { 803 struct in6_addr in6; 804 805 if (nla_len(a) != sizeof(struct in6_addr)) 806 return -EINVAL; 807 in6 = nla_get_in6_addr(a); 808 inetpeer_set_addr_v6(addr, &in6); 809 if (hash) 810 *hash = ipv6_addr_hash(inetpeer_get_addr_v6(addr)); 811 return 0; 812 } 813 return optional ? 1 : -EAFNOSUPPORT; 814 } 815 816 static int parse_nl_addr(struct genl_info *info, struct inetpeer_addr *addr, 817 unsigned int *hash, int optional) 818 { 819 return __parse_nl_addr(info, addr, hash, optional, 820 TCP_METRICS_ATTR_ADDR_IPV4, 821 TCP_METRICS_ATTR_ADDR_IPV6); 822 } 823 824 static int parse_nl_saddr(struct genl_info *info, struct inetpeer_addr *addr) 825 { 826 return __parse_nl_addr(info, addr, NULL, 0, 827 TCP_METRICS_ATTR_SADDR_IPV4, 828 TCP_METRICS_ATTR_SADDR_IPV6); 829 } 830 831 static int tcp_metrics_nl_cmd_get(struct sk_buff *skb, struct genl_info *info) 832 { 833 struct tcp_metrics_block *tm; 834 struct inetpeer_addr saddr, daddr; 835 unsigned int hash; 836 struct sk_buff *msg; 837 struct net *net = genl_info_net(info); 838 void *reply; 839 int ret; 840 bool src = true; 841 842 ret = parse_nl_addr(info, &daddr, &hash, 0); 843 if (ret < 0) 844 return ret; 845 846 ret = parse_nl_saddr(info, &saddr); 847 if (ret < 0) 848 src = false; 849 850 msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL); 851 if (!msg) 852 return -ENOMEM; 853 854 reply = genlmsg_put_reply(msg, info, &tcp_metrics_nl_family, 0, 855 info->genlhdr->cmd); 856 if (!reply) 857 goto nla_put_failure; 858 859 hash ^= net_hash_mix(net); 860 hash = hash_32(hash, tcp_metrics_hash_log); 861 ret = -ESRCH; 862 rcu_read_lock(); 863 for (tm = rcu_dereference(tcp_metrics_hash[hash].chain); tm; 864 tm = rcu_dereference(tm->tcpm_next)) { 865 if (addr_same(&tm->tcpm_daddr, &daddr) && 866 (!src || addr_same(&tm->tcpm_saddr, &saddr)) && 867 net_eq(tm_net(tm), net)) { 868 ret = tcp_metrics_fill_info(msg, tm); 869 break; 870 } 871 } 872 rcu_read_unlock(); 873 if (ret < 0) 874 goto out_free; 875 876 genlmsg_end(msg, reply); 877 return genlmsg_reply(msg, info); 878 879 nla_put_failure: 880 ret = -EMSGSIZE; 881 882 out_free: 883 nlmsg_free(msg); 884 return ret; 885 } 886 887 static void tcp_metrics_flush_all(struct net *net) 888 { 889 unsigned int max_rows = 1U << tcp_metrics_hash_log; 890 struct tcpm_hash_bucket *hb = tcp_metrics_hash; 891 struct tcp_metrics_block *tm; 892 unsigned int row; 893 894 for (row = 0; row < max_rows; row++, hb++) { 895 struct tcp_metrics_block __rcu **pp; 896 spin_lock_bh(&tcp_metrics_lock); 897 pp = &hb->chain; 898 for (tm = deref_locked(*pp); tm; tm = deref_locked(*pp)) { 899 if (net_eq(tm_net(tm), net)) { 900 *pp = tm->tcpm_next; 901 kfree_rcu(tm, rcu_head); 902 } else { 903 pp = &tm->tcpm_next; 904 } 905 } 906 spin_unlock_bh(&tcp_metrics_lock); 907 } 908 } 909 910 static int tcp_metrics_nl_cmd_del(struct sk_buff *skb, struct genl_info *info) 911 { 912 struct tcpm_hash_bucket *hb; 913 struct tcp_metrics_block *tm; 914 struct tcp_metrics_block __rcu **pp; 915 struct inetpeer_addr saddr, daddr; 916 unsigned int hash; 917 struct net *net = genl_info_net(info); 918 int ret; 919 bool src = true, found = false; 920 921 ret = parse_nl_addr(info, &daddr, &hash, 1); 922 if (ret < 0) 923 return ret; 924 if (ret > 0) { 925 tcp_metrics_flush_all(net); 926 return 0; 927 } 928 ret = parse_nl_saddr(info, &saddr); 929 if (ret < 0) 930 src = false; 931 932 hash ^= net_hash_mix(net); 933 hash = hash_32(hash, tcp_metrics_hash_log); 934 hb = tcp_metrics_hash + hash; 935 pp = &hb->chain; 936 spin_lock_bh(&tcp_metrics_lock); 937 for (tm = deref_locked(*pp); tm; tm = deref_locked(*pp)) { 938 if (addr_same(&tm->tcpm_daddr, &daddr) && 939 (!src || addr_same(&tm->tcpm_saddr, &saddr)) && 940 net_eq(tm_net(tm), net)) { 941 *pp = tm->tcpm_next; 942 kfree_rcu(tm, rcu_head); 943 found = true; 944 } else { 945 pp = &tm->tcpm_next; 946 } 947 } 948 spin_unlock_bh(&tcp_metrics_lock); 949 if (!found) 950 return -ESRCH; 951 return 0; 952 } 953 954 static const struct genl_ops tcp_metrics_nl_ops[] = { 955 { 956 .cmd = TCP_METRICS_CMD_GET, 957 .doit = tcp_metrics_nl_cmd_get, 958 .dumpit = tcp_metrics_nl_dump, 959 .policy = tcp_metrics_nl_policy, 960 }, 961 { 962 .cmd = TCP_METRICS_CMD_DEL, 963 .doit = tcp_metrics_nl_cmd_del, 964 .policy = tcp_metrics_nl_policy, 965 .flags = GENL_ADMIN_PERM, 966 }, 967 }; 968 969 static struct genl_family tcp_metrics_nl_family __ro_after_init = { 970 .hdrsize = 0, 971 .name = TCP_METRICS_GENL_NAME, 972 .version = TCP_METRICS_GENL_VERSION, 973 .maxattr = TCP_METRICS_ATTR_MAX, 974 .netnsok = true, 975 .module = THIS_MODULE, 976 .ops = tcp_metrics_nl_ops, 977 .n_ops = ARRAY_SIZE(tcp_metrics_nl_ops), 978 }; 979 980 static unsigned int tcpmhash_entries; 981 static int __init set_tcpmhash_entries(char *str) 982 { 983 ssize_t ret; 984 985 if (!str) 986 return 0; 987 988 ret = kstrtouint(str, 0, &tcpmhash_entries); 989 if (ret) 990 return 0; 991 992 return 1; 993 } 994 __setup("tcpmhash_entries=", set_tcpmhash_entries); 995 996 static int __net_init tcp_net_metrics_init(struct net *net) 997 { 998 size_t size; 999 unsigned int slots; 1000 1001 if (!net_eq(net, &init_net)) 1002 return 0; 1003 1004 slots = tcpmhash_entries; 1005 if (!slots) { 1006 if (totalram_pages >= 128 * 1024) 1007 slots = 16 * 1024; 1008 else 1009 slots = 8 * 1024; 1010 } 1011 1012 tcp_metrics_hash_log = order_base_2(slots); 1013 size = sizeof(struct tcpm_hash_bucket) << tcp_metrics_hash_log; 1014 1015 tcp_metrics_hash = kvzalloc(size, GFP_KERNEL); 1016 if (!tcp_metrics_hash) 1017 return -ENOMEM; 1018 1019 return 0; 1020 } 1021 1022 static void __net_exit tcp_net_metrics_exit(struct net *net) 1023 { 1024 tcp_metrics_flush_all(net); 1025 } 1026 1027 static __net_initdata struct pernet_operations tcp_net_metrics_ops = { 1028 .init = tcp_net_metrics_init, 1029 .exit = tcp_net_metrics_exit, 1030 }; 1031 1032 void __init tcp_metrics_init(void) 1033 { 1034 int ret; 1035 1036 ret = register_pernet_subsys(&tcp_net_metrics_ops); 1037 if (ret < 0) 1038 panic("Could not allocate the tcp_metrics hash table\n"); 1039 1040 ret = genl_register_family(&tcp_metrics_nl_family); 1041 if (ret < 0) 1042 panic("Could not register tcp_metrics generic netlink\n"); 1043 } 1044