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 tm_net(const struct tcp_metrics_block * tm)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 tcp_metric_locked(struct tcp_metrics_block * tm,enum tcp_metric_index idx)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 tcp_metric_get(const struct tcp_metrics_block * tm,enum tcp_metric_index idx)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 tcp_metric_set(struct tcp_metrics_block * tm,enum tcp_metric_index idx,u32 val)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 addr_same(const struct inetpeer_addr * a,const struct inetpeer_addr * b)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 tcpm_suck_dst(struct tcp_metrics_block * tm,const struct dst_entry * dst,bool fastopen_clear)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 tcpm_check_stamp(struct tcp_metrics_block * tm,const struct dst_entry * dst)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 tcpm_new(struct dst_entry * dst,struct inetpeer_addr * saddr,struct inetpeer_addr * daddr,unsigned int hash)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_rcu(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 tcp_get_encode(struct tcp_metrics_block * tm,int depth)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 __tcp_get_metrics(const struct inetpeer_addr * saddr,const struct inetpeer_addr * daddr,struct net * net,unsigned int hash)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 __tcp_get_metrics_req(struct request_sock * req,struct dst_entry * dst)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_rcu(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 tcp_get_metrics(struct sock * sk,struct dst_entry * dst,bool create)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_rcu(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 */ tcp_update_metrics(struct sock * sk)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 tcp_init_metrics(struct sock * sk)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 /* ssthresh may have been reduced unnecessarily during. 474 * 3WHS. Restore it back to its initial default. 475 */ 476 tp->snd_ssthresh = TCP_INFINITE_SSTHRESH; 477 if (!dst) 478 goto reset; 479 480 rcu_read_lock(); 481 tm = tcp_get_metrics(sk, dst, false); 482 if (!tm) { 483 rcu_read_unlock(); 484 goto reset; 485 } 486 487 if (tcp_metric_locked(tm, TCP_METRIC_CWND)) 488 tp->snd_cwnd_clamp = tcp_metric_get(tm, TCP_METRIC_CWND); 489 490 val = READ_ONCE(net->ipv4.sysctl_tcp_no_ssthresh_metrics_save) ? 491 0 : tcp_metric_get(tm, TCP_METRIC_SSTHRESH); 492 if (val) { 493 tp->snd_ssthresh = val; 494 if (tp->snd_ssthresh > tp->snd_cwnd_clamp) 495 tp->snd_ssthresh = tp->snd_cwnd_clamp; 496 } 497 val = tcp_metric_get(tm, TCP_METRIC_REORDERING); 498 if (val && tp->reordering != val) 499 tp->reordering = val; 500 501 crtt = tcp_metric_get(tm, TCP_METRIC_RTT); 502 rcu_read_unlock(); 503 reset: 504 /* The initial RTT measurement from the SYN/SYN-ACK is not ideal 505 * to seed the RTO for later data packets because SYN packets are 506 * small. Use the per-dst cached values to seed the RTO but keep 507 * the RTT estimator variables intact (e.g., srtt, mdev, rttvar). 508 * Later the RTO will be updated immediately upon obtaining the first 509 * data RTT sample (tcp_rtt_estimator()). Hence the cached RTT only 510 * influences the first RTO but not later RTT estimation. 511 * 512 * But if RTT is not available from the SYN (due to retransmits or 513 * syn cookies) or the cache, force a conservative 3secs timeout. 514 * 515 * A bit of theory. RTT is time passed after "normal" sized packet 516 * is sent until it is ACKed. In normal circumstances sending small 517 * packets force peer to delay ACKs and calculation is correct too. 518 * The algorithm is adaptive and, provided we follow specs, it 519 * NEVER underestimate RTT. BUT! If peer tries to make some clever 520 * tricks sort of "quick acks" for time long enough to decrease RTT 521 * to low value, and then abruptly stops to do it and starts to delay 522 * ACKs, wait for troubles. 523 */ 524 if (crtt > tp->srtt_us) { 525 /* Set RTO like tcp_rtt_estimator(), but from cached RTT. */ 526 crtt /= 8 * USEC_PER_SEC / HZ; 527 inet_csk(sk)->icsk_rto = crtt + max(2 * crtt, tcp_rto_min(sk)); 528 } else if (tp->srtt_us == 0) { 529 /* RFC6298: 5.7 We've failed to get a valid RTT sample from 530 * 3WHS. This is most likely due to retransmission, 531 * including spurious one. Reset the RTO back to 3secs 532 * from the more aggressive 1sec to avoid more spurious 533 * retransmission. 534 */ 535 tp->rttvar_us = jiffies_to_usecs(TCP_TIMEOUT_FALLBACK); 536 tp->mdev_us = tp->mdev_max_us = tp->rttvar_us; 537 538 inet_csk(sk)->icsk_rto = TCP_TIMEOUT_FALLBACK; 539 } 540 } 541 tcp_peer_is_proven(struct request_sock * req,struct dst_entry * dst)542 bool tcp_peer_is_proven(struct request_sock *req, struct dst_entry *dst) 543 { 544 struct tcp_metrics_block *tm; 545 bool ret; 546 547 if (!dst) 548 return false; 549 550 rcu_read_lock(); 551 tm = __tcp_get_metrics_req(req, dst); 552 if (tm && tcp_metric_get(tm, TCP_METRIC_RTT)) 553 ret = true; 554 else 555 ret = false; 556 rcu_read_unlock(); 557 558 return ret; 559 } 560 tcp_fastopen_cache_get(struct sock * sk,u16 * mss,struct tcp_fastopen_cookie * cookie)561 void tcp_fastopen_cache_get(struct sock *sk, u16 *mss, 562 struct tcp_fastopen_cookie *cookie) 563 { 564 struct tcp_metrics_block *tm; 565 566 rcu_read_lock(); 567 tm = tcp_get_metrics(sk, __sk_dst_get(sk), false); 568 if (tm) { 569 struct tcp_fastopen_metrics *tfom = &tm->tcpm_fastopen; 570 unsigned int seq; 571 572 do { 573 seq = read_seqbegin(&fastopen_seqlock); 574 if (tfom->mss) 575 *mss = tfom->mss; 576 *cookie = tfom->cookie; 577 if (cookie->len <= 0 && tfom->try_exp == 1) 578 cookie->exp = true; 579 } while (read_seqretry(&fastopen_seqlock, seq)); 580 } 581 rcu_read_unlock(); 582 } 583 tcp_fastopen_cache_set(struct sock * sk,u16 mss,struct tcp_fastopen_cookie * cookie,bool syn_lost,u16 try_exp)584 void tcp_fastopen_cache_set(struct sock *sk, u16 mss, 585 struct tcp_fastopen_cookie *cookie, bool syn_lost, 586 u16 try_exp) 587 { 588 struct dst_entry *dst = __sk_dst_get(sk); 589 struct tcp_metrics_block *tm; 590 591 if (!dst) 592 return; 593 rcu_read_lock(); 594 tm = tcp_get_metrics(sk, dst, true); 595 if (tm) { 596 struct tcp_fastopen_metrics *tfom = &tm->tcpm_fastopen; 597 598 write_seqlock_bh(&fastopen_seqlock); 599 if (mss) 600 tfom->mss = mss; 601 if (cookie && cookie->len > 0) 602 tfom->cookie = *cookie; 603 else if (try_exp > tfom->try_exp && 604 tfom->cookie.len <= 0 && !tfom->cookie.exp) 605 tfom->try_exp = try_exp; 606 if (syn_lost) { 607 ++tfom->syn_loss; 608 tfom->last_syn_loss = jiffies; 609 } else 610 tfom->syn_loss = 0; 611 write_sequnlock_bh(&fastopen_seqlock); 612 } 613 rcu_read_unlock(); 614 } 615 616 static struct genl_family tcp_metrics_nl_family; 617 618 static const struct nla_policy tcp_metrics_nl_policy[TCP_METRICS_ATTR_MAX + 1] = { 619 [TCP_METRICS_ATTR_ADDR_IPV4] = { .type = NLA_U32, }, 620 [TCP_METRICS_ATTR_ADDR_IPV6] = 621 NLA_POLICY_EXACT_LEN(sizeof(struct in6_addr)), 622 623 [TCP_METRICS_ATTR_SADDR_IPV4] = { .type = NLA_U32, }, 624 [TCP_METRICS_ATTR_SADDR_IPV6] = 625 NLA_POLICY_EXACT_LEN(sizeof(struct in6_addr)), 626 627 /* Following attributes are not received for GET/DEL, 628 * we keep them for reference 629 */ 630 #if 0 631 [TCP_METRICS_ATTR_AGE] = { .type = NLA_MSECS, }, 632 [TCP_METRICS_ATTR_TW_TSVAL] = { .type = NLA_U32, }, 633 [TCP_METRICS_ATTR_TW_TS_STAMP] = { .type = NLA_S32, }, 634 [TCP_METRICS_ATTR_VALS] = { .type = NLA_NESTED, }, 635 [TCP_METRICS_ATTR_FOPEN_MSS] = { .type = NLA_U16, }, 636 [TCP_METRICS_ATTR_FOPEN_SYN_DROPS] = { .type = NLA_U16, }, 637 [TCP_METRICS_ATTR_FOPEN_SYN_DROP_TS] = { .type = NLA_MSECS, }, 638 [TCP_METRICS_ATTR_FOPEN_COOKIE] = { .type = NLA_BINARY, 639 .len = TCP_FASTOPEN_COOKIE_MAX, }, 640 #endif 641 }; 642 643 /* Add attributes, caller cancels its header on failure */ tcp_metrics_fill_info(struct sk_buff * msg,struct tcp_metrics_block * tm)644 static int tcp_metrics_fill_info(struct sk_buff *msg, 645 struct tcp_metrics_block *tm) 646 { 647 struct nlattr *nest; 648 int i; 649 650 switch (tm->tcpm_daddr.family) { 651 case AF_INET: 652 if (nla_put_in_addr(msg, TCP_METRICS_ATTR_ADDR_IPV4, 653 inetpeer_get_addr_v4(&tm->tcpm_daddr)) < 0) 654 goto nla_put_failure; 655 if (nla_put_in_addr(msg, TCP_METRICS_ATTR_SADDR_IPV4, 656 inetpeer_get_addr_v4(&tm->tcpm_saddr)) < 0) 657 goto nla_put_failure; 658 break; 659 case AF_INET6: 660 if (nla_put_in6_addr(msg, TCP_METRICS_ATTR_ADDR_IPV6, 661 inetpeer_get_addr_v6(&tm->tcpm_daddr)) < 0) 662 goto nla_put_failure; 663 if (nla_put_in6_addr(msg, TCP_METRICS_ATTR_SADDR_IPV6, 664 inetpeer_get_addr_v6(&tm->tcpm_saddr)) < 0) 665 goto nla_put_failure; 666 break; 667 default: 668 return -EAFNOSUPPORT; 669 } 670 671 if (nla_put_msecs(msg, TCP_METRICS_ATTR_AGE, 672 jiffies - READ_ONCE(tm->tcpm_stamp), 673 TCP_METRICS_ATTR_PAD) < 0) 674 goto nla_put_failure; 675 676 { 677 int n = 0; 678 679 nest = nla_nest_start_noflag(msg, TCP_METRICS_ATTR_VALS); 680 if (!nest) 681 goto nla_put_failure; 682 for (i = 0; i < TCP_METRIC_MAX_KERNEL + 1; i++) { 683 u32 val = tcp_metric_get(tm, i); 684 685 if (!val) 686 continue; 687 if (i == TCP_METRIC_RTT) { 688 if (nla_put_u32(msg, TCP_METRIC_RTT_US + 1, 689 val) < 0) 690 goto nla_put_failure; 691 n++; 692 val = max(val / 1000, 1U); 693 } 694 if (i == TCP_METRIC_RTTVAR) { 695 if (nla_put_u32(msg, TCP_METRIC_RTTVAR_US + 1, 696 val) < 0) 697 goto nla_put_failure; 698 n++; 699 val = max(val / 1000, 1U); 700 } 701 if (nla_put_u32(msg, i + 1, val) < 0) 702 goto nla_put_failure; 703 n++; 704 } 705 if (n) 706 nla_nest_end(msg, nest); 707 else 708 nla_nest_cancel(msg, nest); 709 } 710 711 { 712 struct tcp_fastopen_metrics tfom_copy[1], *tfom; 713 unsigned int seq; 714 715 do { 716 seq = read_seqbegin(&fastopen_seqlock); 717 tfom_copy[0] = tm->tcpm_fastopen; 718 } while (read_seqretry(&fastopen_seqlock, seq)); 719 720 tfom = tfom_copy; 721 if (tfom->mss && 722 nla_put_u16(msg, TCP_METRICS_ATTR_FOPEN_MSS, 723 tfom->mss) < 0) 724 goto nla_put_failure; 725 if (tfom->syn_loss && 726 (nla_put_u16(msg, TCP_METRICS_ATTR_FOPEN_SYN_DROPS, 727 tfom->syn_loss) < 0 || 728 nla_put_msecs(msg, TCP_METRICS_ATTR_FOPEN_SYN_DROP_TS, 729 jiffies - tfom->last_syn_loss, 730 TCP_METRICS_ATTR_PAD) < 0)) 731 goto nla_put_failure; 732 if (tfom->cookie.len > 0 && 733 nla_put(msg, TCP_METRICS_ATTR_FOPEN_COOKIE, 734 tfom->cookie.len, tfom->cookie.val) < 0) 735 goto nla_put_failure; 736 } 737 738 return 0; 739 740 nla_put_failure: 741 return -EMSGSIZE; 742 } 743 tcp_metrics_dump_info(struct sk_buff * skb,struct netlink_callback * cb,struct tcp_metrics_block * tm)744 static int tcp_metrics_dump_info(struct sk_buff *skb, 745 struct netlink_callback *cb, 746 struct tcp_metrics_block *tm) 747 { 748 void *hdr; 749 750 hdr = genlmsg_put(skb, NETLINK_CB(cb->skb).portid, cb->nlh->nlmsg_seq, 751 &tcp_metrics_nl_family, NLM_F_MULTI, 752 TCP_METRICS_CMD_GET); 753 if (!hdr) 754 return -EMSGSIZE; 755 756 if (tcp_metrics_fill_info(skb, tm) < 0) 757 goto nla_put_failure; 758 759 genlmsg_end(skb, hdr); 760 return 0; 761 762 nla_put_failure: 763 genlmsg_cancel(skb, hdr); 764 return -EMSGSIZE; 765 } 766 tcp_metrics_nl_dump(struct sk_buff * skb,struct netlink_callback * cb)767 static int tcp_metrics_nl_dump(struct sk_buff *skb, 768 struct netlink_callback *cb) 769 { 770 struct net *net = sock_net(skb->sk); 771 unsigned int max_rows = 1U << tcp_metrics_hash_log; 772 unsigned int row, s_row = cb->args[0]; 773 int s_col = cb->args[1], col = s_col; 774 int res = 0; 775 776 for (row = s_row; row < max_rows; row++, s_col = 0) { 777 struct tcp_metrics_block *tm; 778 struct tcpm_hash_bucket *hb = tcp_metrics_hash + row; 779 780 rcu_read_lock(); 781 for (col = 0, tm = rcu_dereference(hb->chain); tm; 782 tm = rcu_dereference(tm->tcpm_next), col++) { 783 if (!net_eq(tm_net(tm), net)) 784 continue; 785 if (col < s_col) 786 continue; 787 res = tcp_metrics_dump_info(skb, cb, tm); 788 if (res < 0) { 789 rcu_read_unlock(); 790 goto done; 791 } 792 } 793 rcu_read_unlock(); 794 } 795 796 done: 797 cb->args[0] = row; 798 cb->args[1] = col; 799 return res; 800 } 801 __parse_nl_addr(struct genl_info * info,struct inetpeer_addr * addr,unsigned int * hash,int optional,int v4,int v6)802 static int __parse_nl_addr(struct genl_info *info, struct inetpeer_addr *addr, 803 unsigned int *hash, int optional, int v4, int v6) 804 { 805 struct nlattr *a; 806 807 a = info->attrs[v4]; 808 if (a) { 809 inetpeer_set_addr_v4(addr, nla_get_in_addr(a)); 810 if (hash) 811 *hash = ipv4_addr_hash(inetpeer_get_addr_v4(addr)); 812 return 0; 813 } 814 a = info->attrs[v6]; 815 if (a) { 816 struct in6_addr in6; 817 818 in6 = nla_get_in6_addr(a); 819 inetpeer_set_addr_v6(addr, &in6); 820 if (hash) 821 *hash = ipv6_addr_hash(inetpeer_get_addr_v6(addr)); 822 return 0; 823 } 824 return optional ? 1 : -EAFNOSUPPORT; 825 } 826 parse_nl_addr(struct genl_info * info,struct inetpeer_addr * addr,unsigned int * hash,int optional)827 static int parse_nl_addr(struct genl_info *info, struct inetpeer_addr *addr, 828 unsigned int *hash, int optional) 829 { 830 return __parse_nl_addr(info, addr, hash, optional, 831 TCP_METRICS_ATTR_ADDR_IPV4, 832 TCP_METRICS_ATTR_ADDR_IPV6); 833 } 834 parse_nl_saddr(struct genl_info * info,struct inetpeer_addr * addr)835 static int parse_nl_saddr(struct genl_info *info, struct inetpeer_addr *addr) 836 { 837 return __parse_nl_addr(info, addr, NULL, 0, 838 TCP_METRICS_ATTR_SADDR_IPV4, 839 TCP_METRICS_ATTR_SADDR_IPV6); 840 } 841 tcp_metrics_nl_cmd_get(struct sk_buff * skb,struct genl_info * info)842 static int tcp_metrics_nl_cmd_get(struct sk_buff *skb, struct genl_info *info) 843 { 844 struct tcp_metrics_block *tm; 845 struct inetpeer_addr saddr, daddr; 846 unsigned int hash; 847 struct sk_buff *msg; 848 struct net *net = genl_info_net(info); 849 void *reply; 850 int ret; 851 bool src = true; 852 853 ret = parse_nl_addr(info, &daddr, &hash, 0); 854 if (ret < 0) 855 return ret; 856 857 ret = parse_nl_saddr(info, &saddr); 858 if (ret < 0) 859 src = false; 860 861 msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL); 862 if (!msg) 863 return -ENOMEM; 864 865 reply = genlmsg_put_reply(msg, info, &tcp_metrics_nl_family, 0, 866 info->genlhdr->cmd); 867 if (!reply) 868 goto nla_put_failure; 869 870 hash ^= net_hash_mix(net); 871 hash = hash_32(hash, tcp_metrics_hash_log); 872 ret = -ESRCH; 873 rcu_read_lock(); 874 for (tm = rcu_dereference(tcp_metrics_hash[hash].chain); tm; 875 tm = rcu_dereference(tm->tcpm_next)) { 876 if (addr_same(&tm->tcpm_daddr, &daddr) && 877 (!src || addr_same(&tm->tcpm_saddr, &saddr)) && 878 net_eq(tm_net(tm), net)) { 879 ret = tcp_metrics_fill_info(msg, tm); 880 break; 881 } 882 } 883 rcu_read_unlock(); 884 if (ret < 0) 885 goto out_free; 886 887 genlmsg_end(msg, reply); 888 return genlmsg_reply(msg, info); 889 890 nla_put_failure: 891 ret = -EMSGSIZE; 892 893 out_free: 894 nlmsg_free(msg); 895 return ret; 896 } 897 tcp_metrics_flush_all(struct net * net)898 static void tcp_metrics_flush_all(struct net *net) 899 { 900 unsigned int max_rows = 1U << tcp_metrics_hash_log; 901 struct tcpm_hash_bucket *hb = tcp_metrics_hash; 902 struct tcp_metrics_block *tm; 903 unsigned int row; 904 905 for (row = 0; row < max_rows; row++, hb++) { 906 struct tcp_metrics_block __rcu **pp = &hb->chain; 907 bool match; 908 909 if (!rcu_access_pointer(*pp)) 910 continue; 911 912 spin_lock_bh(&tcp_metrics_lock); 913 for (tm = deref_locked(*pp); tm; tm = deref_locked(*pp)) { 914 match = net ? net_eq(tm_net(tm), net) : 915 !refcount_read(&tm_net(tm)->ns.count); 916 if (match) { 917 rcu_assign_pointer(*pp, tm->tcpm_next); 918 kfree_rcu(tm, rcu_head); 919 } else { 920 pp = &tm->tcpm_next; 921 } 922 } 923 spin_unlock_bh(&tcp_metrics_lock); 924 cond_resched(); 925 } 926 } 927 tcp_metrics_nl_cmd_del(struct sk_buff * skb,struct genl_info * info)928 static int tcp_metrics_nl_cmd_del(struct sk_buff *skb, struct genl_info *info) 929 { 930 struct tcpm_hash_bucket *hb; 931 struct tcp_metrics_block *tm; 932 struct tcp_metrics_block __rcu **pp; 933 struct inetpeer_addr saddr, daddr; 934 unsigned int hash; 935 struct net *net = genl_info_net(info); 936 int ret; 937 bool src = true, found = false; 938 939 ret = parse_nl_addr(info, &daddr, &hash, 1); 940 if (ret < 0) 941 return ret; 942 if (ret > 0) { 943 tcp_metrics_flush_all(net); 944 return 0; 945 } 946 ret = parse_nl_saddr(info, &saddr); 947 if (ret < 0) 948 src = false; 949 950 hash ^= net_hash_mix(net); 951 hash = hash_32(hash, tcp_metrics_hash_log); 952 hb = tcp_metrics_hash + hash; 953 pp = &hb->chain; 954 spin_lock_bh(&tcp_metrics_lock); 955 for (tm = deref_locked(*pp); tm; tm = deref_locked(*pp)) { 956 if (addr_same(&tm->tcpm_daddr, &daddr) && 957 (!src || addr_same(&tm->tcpm_saddr, &saddr)) && 958 net_eq(tm_net(tm), net)) { 959 rcu_assign_pointer(*pp, tm->tcpm_next); 960 kfree_rcu(tm, rcu_head); 961 found = true; 962 } else { 963 pp = &tm->tcpm_next; 964 } 965 } 966 spin_unlock_bh(&tcp_metrics_lock); 967 if (!found) 968 return -ESRCH; 969 return 0; 970 } 971 972 static const struct genl_small_ops tcp_metrics_nl_ops[] = { 973 { 974 .cmd = TCP_METRICS_CMD_GET, 975 .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP, 976 .doit = tcp_metrics_nl_cmd_get, 977 .dumpit = tcp_metrics_nl_dump, 978 }, 979 { 980 .cmd = TCP_METRICS_CMD_DEL, 981 .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP, 982 .doit = tcp_metrics_nl_cmd_del, 983 .flags = GENL_ADMIN_PERM, 984 }, 985 }; 986 987 static struct genl_family tcp_metrics_nl_family __ro_after_init = { 988 .hdrsize = 0, 989 .name = TCP_METRICS_GENL_NAME, 990 .version = TCP_METRICS_GENL_VERSION, 991 .maxattr = TCP_METRICS_ATTR_MAX, 992 .policy = tcp_metrics_nl_policy, 993 .netnsok = true, 994 .parallel_ops = true, 995 .module = THIS_MODULE, 996 .small_ops = tcp_metrics_nl_ops, 997 .n_small_ops = ARRAY_SIZE(tcp_metrics_nl_ops), 998 .resv_start_op = TCP_METRICS_CMD_DEL + 1, 999 }; 1000 1001 static unsigned int tcpmhash_entries __initdata; set_tcpmhash_entries(char * str)1002 static int __init set_tcpmhash_entries(char *str) 1003 { 1004 ssize_t ret; 1005 1006 if (!str) 1007 return 0; 1008 1009 ret = kstrtouint(str, 0, &tcpmhash_entries); 1010 if (ret) 1011 return 0; 1012 1013 return 1; 1014 } 1015 __setup("tcpmhash_entries=", set_tcpmhash_entries); 1016 tcp_metrics_hash_alloc(void)1017 static void __init tcp_metrics_hash_alloc(void) 1018 { 1019 unsigned int slots = tcpmhash_entries; 1020 size_t size; 1021 1022 if (!slots) { 1023 if (totalram_pages() >= 128 * 1024) 1024 slots = 16 * 1024; 1025 else 1026 slots = 8 * 1024; 1027 } 1028 1029 tcp_metrics_hash_log = order_base_2(slots); 1030 size = sizeof(struct tcpm_hash_bucket) << tcp_metrics_hash_log; 1031 1032 tcp_metrics_hash = kvzalloc(size, GFP_KERNEL); 1033 if (!tcp_metrics_hash) 1034 panic("Could not allocate the tcp_metrics hash table\n"); 1035 } 1036 tcp_net_metrics_exit_batch(struct list_head * net_exit_list)1037 static void __net_exit tcp_net_metrics_exit_batch(struct list_head *net_exit_list) 1038 { 1039 tcp_metrics_flush_all(NULL); 1040 } 1041 1042 static __net_initdata struct pernet_operations tcp_net_metrics_ops = { 1043 .exit_batch = tcp_net_metrics_exit_batch, 1044 }; 1045 tcp_metrics_init(void)1046 void __init tcp_metrics_init(void) 1047 { 1048 int ret; 1049 1050 tcp_metrics_hash_alloc(); 1051 1052 ret = register_pernet_subsys(&tcp_net_metrics_ops); 1053 if (ret < 0) 1054 panic("Could not register tcp_net_metrics_ops\n"); 1055 1056 ret = genl_register_family(&tcp_metrics_nl_family); 1057 if (ret < 0) 1058 panic("Could not register tcp_metrics generic netlink\n"); 1059 } 1060