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