1 #include <linux/rcupdate.h> 2 #include <linux/spinlock.h> 3 #include <linux/jiffies.h> 4 #include <linux/module.h> 5 #include <linux/cache.h> 6 #include <linux/slab.h> 7 #include <linux/init.h> 8 #include <linux/tcp.h> 9 #include <linux/hash.h> 10 #include <linux/tcp_metrics.h> 11 #include <linux/vmalloc.h> 12 13 #include <net/inet_connection_sock.h> 14 #include <net/net_namespace.h> 15 #include <net/request_sock.h> 16 #include <net/inetpeer.h> 17 #include <net/sock.h> 18 #include <net/ipv6.h> 19 #include <net/dst.h> 20 #include <net/tcp.h> 21 #include <net/genetlink.h> 22 23 static struct tcp_metrics_block *__tcp_get_metrics(const struct inetpeer_addr *saddr, 24 const struct inetpeer_addr *daddr, 25 struct net *net, unsigned int hash); 26 27 struct tcp_fastopen_metrics { 28 u16 mss; 29 u16 syn_loss:10, /* Recurring Fast Open SYN losses */ 30 try_exp:2; /* Request w/ exp. option (once) */ 31 unsigned long last_syn_loss; /* Last Fast Open SYN loss */ 32 struct tcp_fastopen_cookie cookie; 33 }; 34 35 /* TCP_METRIC_MAX includes 2 extra fields for userspace compatibility 36 * Kernel only stores RTT and RTTVAR in usec resolution 37 */ 38 #define TCP_METRIC_MAX_KERNEL (TCP_METRIC_MAX - 2) 39 40 struct tcp_metrics_block { 41 struct tcp_metrics_block __rcu *tcpm_next; 42 possible_net_t tcpm_net; 43 struct inetpeer_addr tcpm_saddr; 44 struct inetpeer_addr tcpm_daddr; 45 unsigned long tcpm_stamp; 46 u32 tcpm_lock; 47 u32 tcpm_vals[TCP_METRIC_MAX_KERNEL + 1]; 48 struct tcp_fastopen_metrics tcpm_fastopen; 49 50 struct rcu_head rcu_head; 51 }; 52 53 static inline struct net *tm_net(struct tcp_metrics_block *tm) 54 { 55 return read_pnet(&tm->tcpm_net); 56 } 57 58 static bool tcp_metric_locked(struct tcp_metrics_block *tm, 59 enum tcp_metric_index idx) 60 { 61 return tm->tcpm_lock & (1 << idx); 62 } 63 64 static u32 tcp_metric_get(struct tcp_metrics_block *tm, 65 enum tcp_metric_index idx) 66 { 67 return tm->tcpm_vals[idx]; 68 } 69 70 static void tcp_metric_set(struct tcp_metrics_block *tm, 71 enum tcp_metric_index idx, 72 u32 val) 73 { 74 tm->tcpm_vals[idx] = val; 75 } 76 77 static bool addr_same(const struct inetpeer_addr *a, 78 const struct inetpeer_addr *b) 79 { 80 return inetpeer_addr_cmp(a, b) == 0; 81 } 82 83 struct tcpm_hash_bucket { 84 struct tcp_metrics_block __rcu *chain; 85 }; 86 87 static struct tcpm_hash_bucket *tcp_metrics_hash __read_mostly; 88 static unsigned int tcp_metrics_hash_log __read_mostly; 89 90 static DEFINE_SPINLOCK(tcp_metrics_lock); 91 92 static void tcpm_suck_dst(struct tcp_metrics_block *tm, 93 const struct dst_entry *dst, 94 bool fastopen_clear) 95 { 96 u32 msval; 97 u32 val; 98 99 tm->tcpm_stamp = jiffies; 100 101 val = 0; 102 if (dst_metric_locked(dst, RTAX_RTT)) 103 val |= 1 << TCP_METRIC_RTT; 104 if (dst_metric_locked(dst, RTAX_RTTVAR)) 105 val |= 1 << TCP_METRIC_RTTVAR; 106 if (dst_metric_locked(dst, RTAX_SSTHRESH)) 107 val |= 1 << TCP_METRIC_SSTHRESH; 108 if (dst_metric_locked(dst, RTAX_CWND)) 109 val |= 1 << TCP_METRIC_CWND; 110 if (dst_metric_locked(dst, RTAX_REORDERING)) 111 val |= 1 << TCP_METRIC_REORDERING; 112 tm->tcpm_lock = val; 113 114 msval = dst_metric_raw(dst, RTAX_RTT); 115 tm->tcpm_vals[TCP_METRIC_RTT] = msval * USEC_PER_MSEC; 116 117 msval = dst_metric_raw(dst, RTAX_RTTVAR); 118 tm->tcpm_vals[TCP_METRIC_RTTVAR] = msval * USEC_PER_MSEC; 119 tm->tcpm_vals[TCP_METRIC_SSTHRESH] = dst_metric_raw(dst, RTAX_SSTHRESH); 120 tm->tcpm_vals[TCP_METRIC_CWND] = dst_metric_raw(dst, RTAX_CWND); 121 tm->tcpm_vals[TCP_METRIC_REORDERING] = dst_metric_raw(dst, RTAX_REORDERING); 122 if (fastopen_clear) { 123 tm->tcpm_fastopen.mss = 0; 124 tm->tcpm_fastopen.syn_loss = 0; 125 tm->tcpm_fastopen.try_exp = 0; 126 tm->tcpm_fastopen.cookie.exp = false; 127 tm->tcpm_fastopen.cookie.len = 0; 128 } 129 } 130 131 #define TCP_METRICS_TIMEOUT (60 * 60 * HZ) 132 133 static void tcpm_check_stamp(struct tcp_metrics_block *tm, struct dst_entry *dst) 134 { 135 if (tm && unlikely(time_after(jiffies, tm->tcpm_stamp + TCP_METRICS_TIMEOUT))) 136 tcpm_suck_dst(tm, dst, false); 137 } 138 139 #define TCP_METRICS_RECLAIM_DEPTH 5 140 #define TCP_METRICS_RECLAIM_PTR (struct tcp_metrics_block *) 0x1UL 141 142 #define deref_locked(p) \ 143 rcu_dereference_protected(p, lockdep_is_held(&tcp_metrics_lock)) 144 145 static struct tcp_metrics_block *tcpm_new(struct dst_entry *dst, 146 struct inetpeer_addr *saddr, 147 struct inetpeer_addr *daddr, 148 unsigned int hash) 149 { 150 struct tcp_metrics_block *tm; 151 struct net *net; 152 bool reclaim = false; 153 154 spin_lock_bh(&tcp_metrics_lock); 155 net = dev_net(dst->dev); 156 157 /* While waiting for the spin-lock the cache might have been populated 158 * with this entry and so we have to check again. 159 */ 160 tm = __tcp_get_metrics(saddr, daddr, net, hash); 161 if (tm == TCP_METRICS_RECLAIM_PTR) { 162 reclaim = true; 163 tm = NULL; 164 } 165 if (tm) { 166 tcpm_check_stamp(tm, dst); 167 goto out_unlock; 168 } 169 170 if (unlikely(reclaim)) { 171 struct tcp_metrics_block *oldest; 172 173 oldest = deref_locked(tcp_metrics_hash[hash].chain); 174 for (tm = deref_locked(oldest->tcpm_next); tm; 175 tm = deref_locked(tm->tcpm_next)) { 176 if (time_before(tm->tcpm_stamp, oldest->tcpm_stamp)) 177 oldest = tm; 178 } 179 tm = oldest; 180 } else { 181 tm = kmalloc(sizeof(*tm), GFP_ATOMIC); 182 if (!tm) 183 goto out_unlock; 184 } 185 write_pnet(&tm->tcpm_net, net); 186 tm->tcpm_saddr = *saddr; 187 tm->tcpm_daddr = *daddr; 188 189 tcpm_suck_dst(tm, dst, true); 190 191 if (likely(!reclaim)) { 192 tm->tcpm_next = tcp_metrics_hash[hash].chain; 193 rcu_assign_pointer(tcp_metrics_hash[hash].chain, tm); 194 } 195 196 out_unlock: 197 spin_unlock_bh(&tcp_metrics_lock); 198 return tm; 199 } 200 201 static struct tcp_metrics_block *tcp_get_encode(struct tcp_metrics_block *tm, int depth) 202 { 203 if (tm) 204 return tm; 205 if (depth > TCP_METRICS_RECLAIM_DEPTH) 206 return TCP_METRICS_RECLAIM_PTR; 207 return NULL; 208 } 209 210 static struct tcp_metrics_block *__tcp_get_metrics(const struct inetpeer_addr *saddr, 211 const struct inetpeer_addr *daddr, 212 struct net *net, unsigned int hash) 213 { 214 struct tcp_metrics_block *tm; 215 int depth = 0; 216 217 for (tm = rcu_dereference(tcp_metrics_hash[hash].chain); tm; 218 tm = rcu_dereference(tm->tcpm_next)) { 219 if (addr_same(&tm->tcpm_saddr, saddr) && 220 addr_same(&tm->tcpm_daddr, daddr) && 221 net_eq(tm_net(tm), net)) 222 break; 223 depth++; 224 } 225 return tcp_get_encode(tm, depth); 226 } 227 228 static struct tcp_metrics_block *__tcp_get_metrics_req(struct request_sock *req, 229 struct dst_entry *dst) 230 { 231 struct tcp_metrics_block *tm; 232 struct inetpeer_addr saddr, daddr; 233 unsigned int hash; 234 struct net *net; 235 236 saddr.family = req->rsk_ops->family; 237 daddr.family = req->rsk_ops->family; 238 switch (daddr.family) { 239 case AF_INET: 240 inetpeer_set_addr_v4(&saddr, inet_rsk(req)->ir_loc_addr); 241 inetpeer_set_addr_v4(&daddr, inet_rsk(req)->ir_rmt_addr); 242 hash = ipv4_addr_hash(inet_rsk(req)->ir_rmt_addr); 243 break; 244 #if IS_ENABLED(CONFIG_IPV6) 245 case AF_INET6: 246 inetpeer_set_addr_v6(&saddr, &inet_rsk(req)->ir_v6_loc_addr); 247 inetpeer_set_addr_v6(&daddr, &inet_rsk(req)->ir_v6_rmt_addr); 248 hash = ipv6_addr_hash(&inet_rsk(req)->ir_v6_rmt_addr); 249 break; 250 #endif 251 default: 252 return NULL; 253 } 254 255 net = dev_net(dst->dev); 256 hash ^= net_hash_mix(net); 257 hash = hash_32(hash, tcp_metrics_hash_log); 258 259 for (tm = rcu_dereference(tcp_metrics_hash[hash].chain); tm; 260 tm = rcu_dereference(tm->tcpm_next)) { 261 if (addr_same(&tm->tcpm_saddr, &saddr) && 262 addr_same(&tm->tcpm_daddr, &daddr) && 263 net_eq(tm_net(tm), net)) 264 break; 265 } 266 tcpm_check_stamp(tm, dst); 267 return tm; 268 } 269 270 static struct tcp_metrics_block *tcp_get_metrics(struct sock *sk, 271 struct dst_entry *dst, 272 bool create) 273 { 274 struct tcp_metrics_block *tm; 275 struct inetpeer_addr saddr, daddr; 276 unsigned int hash; 277 struct net *net; 278 279 if (sk->sk_family == AF_INET) { 280 inetpeer_set_addr_v4(&saddr, inet_sk(sk)->inet_saddr); 281 inetpeer_set_addr_v4(&daddr, inet_sk(sk)->inet_daddr); 282 hash = ipv4_addr_hash(inet_sk(sk)->inet_daddr); 283 } 284 #if IS_ENABLED(CONFIG_IPV6) 285 else if (sk->sk_family == AF_INET6) { 286 if (ipv6_addr_v4mapped(&sk->sk_v6_daddr)) { 287 inetpeer_set_addr_v4(&saddr, inet_sk(sk)->inet_saddr); 288 inetpeer_set_addr_v4(&daddr, inet_sk(sk)->inet_daddr); 289 hash = ipv4_addr_hash(inet_sk(sk)->inet_daddr); 290 } else { 291 inetpeer_set_addr_v6(&saddr, &sk->sk_v6_rcv_saddr); 292 inetpeer_set_addr_v6(&daddr, &sk->sk_v6_daddr); 293 hash = ipv6_addr_hash(&sk->sk_v6_daddr); 294 } 295 } 296 #endif 297 else 298 return NULL; 299 300 net = dev_net(dst->dev); 301 hash ^= net_hash_mix(net); 302 hash = hash_32(hash, tcp_metrics_hash_log); 303 304 tm = __tcp_get_metrics(&saddr, &daddr, net, hash); 305 if (tm == TCP_METRICS_RECLAIM_PTR) 306 tm = NULL; 307 if (!tm && create) 308 tm = tcpm_new(dst, &saddr, &daddr, hash); 309 else 310 tcpm_check_stamp(tm, dst); 311 312 return tm; 313 } 314 315 /* Save metrics learned by this TCP session. This function is called 316 * only, when TCP finishes successfully i.e. when it enters TIME-WAIT 317 * or goes from LAST-ACK to CLOSE. 318 */ 319 void tcp_update_metrics(struct sock *sk) 320 { 321 const struct inet_connection_sock *icsk = inet_csk(sk); 322 struct dst_entry *dst = __sk_dst_get(sk); 323 struct tcp_sock *tp = tcp_sk(sk); 324 struct net *net = sock_net(sk); 325 struct tcp_metrics_block *tm; 326 unsigned long rtt; 327 u32 val; 328 int m; 329 330 sk_dst_confirm(sk); 331 if (net->ipv4.sysctl_tcp_nometrics_save || !dst) 332 return; 333 334 rcu_read_lock(); 335 if (icsk->icsk_backoff || !tp->srtt_us) { 336 /* This session failed to estimate rtt. Why? 337 * Probably, no packets returned in time. Reset our 338 * results. 339 */ 340 tm = tcp_get_metrics(sk, dst, false); 341 if (tm && !tcp_metric_locked(tm, TCP_METRIC_RTT)) 342 tcp_metric_set(tm, TCP_METRIC_RTT, 0); 343 goto out_unlock; 344 } else 345 tm = tcp_get_metrics(sk, dst, true); 346 347 if (!tm) 348 goto out_unlock; 349 350 rtt = tcp_metric_get(tm, TCP_METRIC_RTT); 351 m = rtt - tp->srtt_us; 352 353 /* If newly calculated rtt larger than stored one, store new 354 * one. Otherwise, use EWMA. Remember, rtt overestimation is 355 * always better than underestimation. 356 */ 357 if (!tcp_metric_locked(tm, TCP_METRIC_RTT)) { 358 if (m <= 0) 359 rtt = tp->srtt_us; 360 else 361 rtt -= (m >> 3); 362 tcp_metric_set(tm, TCP_METRIC_RTT, rtt); 363 } 364 365 if (!tcp_metric_locked(tm, TCP_METRIC_RTTVAR)) { 366 unsigned long var; 367 368 if (m < 0) 369 m = -m; 370 371 /* Scale deviation to rttvar fixed point */ 372 m >>= 1; 373 if (m < tp->mdev_us) 374 m = tp->mdev_us; 375 376 var = tcp_metric_get(tm, TCP_METRIC_RTTVAR); 377 if (m >= var) 378 var = m; 379 else 380 var -= (var - m) >> 2; 381 382 tcp_metric_set(tm, TCP_METRIC_RTTVAR, var); 383 } 384 385 if (tcp_in_initial_slowstart(tp)) { 386 /* Slow start still did not finish. */ 387 if (!tcp_metric_locked(tm, TCP_METRIC_SSTHRESH)) { 388 val = tcp_metric_get(tm, TCP_METRIC_SSTHRESH); 389 if (val && (tp->snd_cwnd >> 1) > val) 390 tcp_metric_set(tm, TCP_METRIC_SSTHRESH, 391 tp->snd_cwnd >> 1); 392 } 393 if (!tcp_metric_locked(tm, TCP_METRIC_CWND)) { 394 val = tcp_metric_get(tm, TCP_METRIC_CWND); 395 if (tp->snd_cwnd > val) 396 tcp_metric_set(tm, TCP_METRIC_CWND, 397 tp->snd_cwnd); 398 } 399 } else if (!tcp_in_slow_start(tp) && 400 icsk->icsk_ca_state == TCP_CA_Open) { 401 /* Cong. avoidance phase, cwnd is reliable. */ 402 if (!tcp_metric_locked(tm, TCP_METRIC_SSTHRESH)) 403 tcp_metric_set(tm, TCP_METRIC_SSTHRESH, 404 max(tp->snd_cwnd >> 1, tp->snd_ssthresh)); 405 if (!tcp_metric_locked(tm, TCP_METRIC_CWND)) { 406 val = tcp_metric_get(tm, TCP_METRIC_CWND); 407 tcp_metric_set(tm, TCP_METRIC_CWND, (val + tp->snd_cwnd) >> 1); 408 } 409 } else { 410 /* Else slow start did not finish, cwnd is non-sense, 411 * ssthresh may be also invalid. 412 */ 413 if (!tcp_metric_locked(tm, TCP_METRIC_CWND)) { 414 val = tcp_metric_get(tm, TCP_METRIC_CWND); 415 tcp_metric_set(tm, TCP_METRIC_CWND, 416 (val + tp->snd_ssthresh) >> 1); 417 } 418 if (!tcp_metric_locked(tm, TCP_METRIC_SSTHRESH)) { 419 val = tcp_metric_get(tm, TCP_METRIC_SSTHRESH); 420 if (val && tp->snd_ssthresh > val) 421 tcp_metric_set(tm, TCP_METRIC_SSTHRESH, 422 tp->snd_ssthresh); 423 } 424 if (!tcp_metric_locked(tm, TCP_METRIC_REORDERING)) { 425 val = tcp_metric_get(tm, TCP_METRIC_REORDERING); 426 if (val < tp->reordering && 427 tp->reordering != net->ipv4.sysctl_tcp_reordering) 428 tcp_metric_set(tm, TCP_METRIC_REORDERING, 429 tp->reordering); 430 } 431 } 432 tm->tcpm_stamp = jiffies; 433 out_unlock: 434 rcu_read_unlock(); 435 } 436 437 /* Initialize metrics on socket. */ 438 439 void tcp_init_metrics(struct sock *sk) 440 { 441 struct dst_entry *dst = __sk_dst_get(sk); 442 struct tcp_sock *tp = tcp_sk(sk); 443 struct tcp_metrics_block *tm; 444 u32 val, crtt = 0; /* cached RTT scaled by 8 */ 445 446 sk_dst_confirm(sk); 447 if (!dst) 448 goto reset; 449 450 rcu_read_lock(); 451 tm = tcp_get_metrics(sk, dst, true); 452 if (!tm) { 453 rcu_read_unlock(); 454 goto reset; 455 } 456 457 if (tcp_metric_locked(tm, TCP_METRIC_CWND)) 458 tp->snd_cwnd_clamp = tcp_metric_get(tm, TCP_METRIC_CWND); 459 460 val = tcp_metric_get(tm, TCP_METRIC_SSTHRESH); 461 if (val) { 462 tp->snd_ssthresh = val; 463 if (tp->snd_ssthresh > tp->snd_cwnd_clamp) 464 tp->snd_ssthresh = tp->snd_cwnd_clamp; 465 } else { 466 /* ssthresh may have been reduced unnecessarily during. 467 * 3WHS. Restore it back to its initial default. 468 */ 469 tp->snd_ssthresh = TCP_INFINITE_SSTHRESH; 470 } 471 val = tcp_metric_get(tm, TCP_METRIC_REORDERING); 472 if (val && tp->reordering != val) { 473 tcp_disable_fack(tp); 474 tp->reordering = val; 475 } 476 477 crtt = tcp_metric_get(tm, TCP_METRIC_RTT); 478 rcu_read_unlock(); 479 reset: 480 /* The initial RTT measurement from the SYN/SYN-ACK is not ideal 481 * to seed the RTO for later data packets because SYN packets are 482 * small. Use the per-dst cached values to seed the RTO but keep 483 * the RTT estimator variables intact (e.g., srtt, mdev, rttvar). 484 * Later the RTO will be updated immediately upon obtaining the first 485 * data RTT sample (tcp_rtt_estimator()). Hence the cached RTT only 486 * influences the first RTO but not later RTT estimation. 487 * 488 * But if RTT is not available from the SYN (due to retransmits or 489 * syn cookies) or the cache, force a conservative 3secs timeout. 490 * 491 * A bit of theory. RTT is time passed after "normal" sized packet 492 * is sent until it is ACKed. In normal circumstances sending small 493 * packets force peer to delay ACKs and calculation is correct too. 494 * The algorithm is adaptive and, provided we follow specs, it 495 * NEVER underestimate RTT. BUT! If peer tries to make some clever 496 * tricks sort of "quick acks" for time long enough to decrease RTT 497 * to low value, and then abruptly stops to do it and starts to delay 498 * ACKs, wait for troubles. 499 */ 500 if (crtt > tp->srtt_us) { 501 /* Set RTO like tcp_rtt_estimator(), but from cached RTT. */ 502 crtt /= 8 * USEC_PER_SEC / HZ; 503 inet_csk(sk)->icsk_rto = crtt + max(2 * crtt, tcp_rto_min(sk)); 504 } else if (tp->srtt_us == 0) { 505 /* RFC6298: 5.7 We've failed to get a valid RTT sample from 506 * 3WHS. This is most likely due to retransmission, 507 * including spurious one. Reset the RTO back to 3secs 508 * from the more aggressive 1sec to avoid more spurious 509 * retransmission. 510 */ 511 tp->rttvar_us = jiffies_to_usecs(TCP_TIMEOUT_FALLBACK); 512 tp->mdev_us = tp->mdev_max_us = tp->rttvar_us; 513 514 inet_csk(sk)->icsk_rto = TCP_TIMEOUT_FALLBACK; 515 } 516 /* Cut cwnd down to 1 per RFC5681 if SYN or SYN-ACK has been 517 * retransmitted. In light of RFC6298 more aggressive 1sec 518 * initRTO, we only reset cwnd when more than 1 SYN/SYN-ACK 519 * retransmission has occurred. 520 */ 521 if (tp->total_retrans > 1) 522 tp->snd_cwnd = 1; 523 else 524 tp->snd_cwnd = tcp_init_cwnd(tp, dst); 525 tp->snd_cwnd_stamp = tcp_jiffies32; 526 } 527 528 bool tcp_peer_is_proven(struct request_sock *req, struct dst_entry *dst) 529 { 530 struct tcp_metrics_block *tm; 531 bool ret; 532 533 if (!dst) 534 return false; 535 536 rcu_read_lock(); 537 tm = __tcp_get_metrics_req(req, dst); 538 if (tm && tcp_metric_get(tm, TCP_METRIC_RTT)) 539 ret = true; 540 else 541 ret = false; 542 rcu_read_unlock(); 543 544 return ret; 545 } 546 547 static DEFINE_SEQLOCK(fastopen_seqlock); 548 549 void tcp_fastopen_cache_get(struct sock *sk, u16 *mss, 550 struct tcp_fastopen_cookie *cookie, 551 int *syn_loss, unsigned long *last_syn_loss) 552 { 553 struct tcp_metrics_block *tm; 554 555 rcu_read_lock(); 556 tm = tcp_get_metrics(sk, __sk_dst_get(sk), false); 557 if (tm) { 558 struct tcp_fastopen_metrics *tfom = &tm->tcpm_fastopen; 559 unsigned int seq; 560 561 do { 562 seq = read_seqbegin(&fastopen_seqlock); 563 if (tfom->mss) 564 *mss = tfom->mss; 565 *cookie = tfom->cookie; 566 if (cookie->len <= 0 && tfom->try_exp == 1) 567 cookie->exp = true; 568 *syn_loss = tfom->syn_loss; 569 *last_syn_loss = *syn_loss ? tfom->last_syn_loss : 0; 570 } while (read_seqretry(&fastopen_seqlock, seq)); 571 } 572 rcu_read_unlock(); 573 } 574 575 void tcp_fastopen_cache_set(struct sock *sk, u16 mss, 576 struct tcp_fastopen_cookie *cookie, bool syn_lost, 577 u16 try_exp) 578 { 579 struct dst_entry *dst = __sk_dst_get(sk); 580 struct tcp_metrics_block *tm; 581 582 if (!dst) 583 return; 584 rcu_read_lock(); 585 tm = tcp_get_metrics(sk, dst, true); 586 if (tm) { 587 struct tcp_fastopen_metrics *tfom = &tm->tcpm_fastopen; 588 589 write_seqlock_bh(&fastopen_seqlock); 590 if (mss) 591 tfom->mss = mss; 592 if (cookie && cookie->len > 0) 593 tfom->cookie = *cookie; 594 else if (try_exp > tfom->try_exp && 595 tfom->cookie.len <= 0 && !tfom->cookie.exp) 596 tfom->try_exp = try_exp; 597 if (syn_lost) { 598 ++tfom->syn_loss; 599 tfom->last_syn_loss = jiffies; 600 } else 601 tfom->syn_loss = 0; 602 write_sequnlock_bh(&fastopen_seqlock); 603 } 604 rcu_read_unlock(); 605 } 606 607 static struct genl_family tcp_metrics_nl_family; 608 609 static const struct nla_policy tcp_metrics_nl_policy[TCP_METRICS_ATTR_MAX + 1] = { 610 [TCP_METRICS_ATTR_ADDR_IPV4] = { .type = NLA_U32, }, 611 [TCP_METRICS_ATTR_ADDR_IPV6] = { .type = NLA_BINARY, 612 .len = sizeof(struct in6_addr), }, 613 /* Following attributes are not received for GET/DEL, 614 * we keep them for reference 615 */ 616 #if 0 617 [TCP_METRICS_ATTR_AGE] = { .type = NLA_MSECS, }, 618 [TCP_METRICS_ATTR_TW_TSVAL] = { .type = NLA_U32, }, 619 [TCP_METRICS_ATTR_TW_TS_STAMP] = { .type = NLA_S32, }, 620 [TCP_METRICS_ATTR_VALS] = { .type = NLA_NESTED, }, 621 [TCP_METRICS_ATTR_FOPEN_MSS] = { .type = NLA_U16, }, 622 [TCP_METRICS_ATTR_FOPEN_SYN_DROPS] = { .type = NLA_U16, }, 623 [TCP_METRICS_ATTR_FOPEN_SYN_DROP_TS] = { .type = NLA_MSECS, }, 624 [TCP_METRICS_ATTR_FOPEN_COOKIE] = { .type = NLA_BINARY, 625 .len = TCP_FASTOPEN_COOKIE_MAX, }, 626 #endif 627 }; 628 629 /* Add attributes, caller cancels its header on failure */ 630 static int tcp_metrics_fill_info(struct sk_buff *msg, 631 struct tcp_metrics_block *tm) 632 { 633 struct nlattr *nest; 634 int i; 635 636 switch (tm->tcpm_daddr.family) { 637 case AF_INET: 638 if (nla_put_in_addr(msg, TCP_METRICS_ATTR_ADDR_IPV4, 639 inetpeer_get_addr_v4(&tm->tcpm_daddr)) < 0) 640 goto nla_put_failure; 641 if (nla_put_in_addr(msg, TCP_METRICS_ATTR_SADDR_IPV4, 642 inetpeer_get_addr_v4(&tm->tcpm_saddr)) < 0) 643 goto nla_put_failure; 644 break; 645 case AF_INET6: 646 if (nla_put_in6_addr(msg, TCP_METRICS_ATTR_ADDR_IPV6, 647 inetpeer_get_addr_v6(&tm->tcpm_daddr)) < 0) 648 goto nla_put_failure; 649 if (nla_put_in6_addr(msg, TCP_METRICS_ATTR_SADDR_IPV6, 650 inetpeer_get_addr_v6(&tm->tcpm_saddr)) < 0) 651 goto nla_put_failure; 652 break; 653 default: 654 return -EAFNOSUPPORT; 655 } 656 657 if (nla_put_msecs(msg, TCP_METRICS_ATTR_AGE, 658 jiffies - tm->tcpm_stamp, 659 TCP_METRICS_ATTR_PAD) < 0) 660 goto nla_put_failure; 661 662 { 663 int n = 0; 664 665 nest = nla_nest_start(msg, TCP_METRICS_ATTR_VALS); 666 if (!nest) 667 goto nla_put_failure; 668 for (i = 0; i < TCP_METRIC_MAX_KERNEL + 1; i++) { 669 u32 val = tm->tcpm_vals[i]; 670 671 if (!val) 672 continue; 673 if (i == TCP_METRIC_RTT) { 674 if (nla_put_u32(msg, TCP_METRIC_RTT_US + 1, 675 val) < 0) 676 goto nla_put_failure; 677 n++; 678 val = max(val / 1000, 1U); 679 } 680 if (i == TCP_METRIC_RTTVAR) { 681 if (nla_put_u32(msg, TCP_METRIC_RTTVAR_US + 1, 682 val) < 0) 683 goto nla_put_failure; 684 n++; 685 val = max(val / 1000, 1U); 686 } 687 if (nla_put_u32(msg, i + 1, val) < 0) 688 goto nla_put_failure; 689 n++; 690 } 691 if (n) 692 nla_nest_end(msg, nest); 693 else 694 nla_nest_cancel(msg, nest); 695 } 696 697 { 698 struct tcp_fastopen_metrics tfom_copy[1], *tfom; 699 unsigned int seq; 700 701 do { 702 seq = read_seqbegin(&fastopen_seqlock); 703 tfom_copy[0] = tm->tcpm_fastopen; 704 } while (read_seqretry(&fastopen_seqlock, seq)); 705 706 tfom = tfom_copy; 707 if (tfom->mss && 708 nla_put_u16(msg, TCP_METRICS_ATTR_FOPEN_MSS, 709 tfom->mss) < 0) 710 goto nla_put_failure; 711 if (tfom->syn_loss && 712 (nla_put_u16(msg, TCP_METRICS_ATTR_FOPEN_SYN_DROPS, 713 tfom->syn_loss) < 0 || 714 nla_put_msecs(msg, TCP_METRICS_ATTR_FOPEN_SYN_DROP_TS, 715 jiffies - tfom->last_syn_loss, 716 TCP_METRICS_ATTR_PAD) < 0)) 717 goto nla_put_failure; 718 if (tfom->cookie.len > 0 && 719 nla_put(msg, TCP_METRICS_ATTR_FOPEN_COOKIE, 720 tfom->cookie.len, tfom->cookie.val) < 0) 721 goto nla_put_failure; 722 } 723 724 return 0; 725 726 nla_put_failure: 727 return -EMSGSIZE; 728 } 729 730 static int tcp_metrics_dump_info(struct sk_buff *skb, 731 struct netlink_callback *cb, 732 struct tcp_metrics_block *tm) 733 { 734 void *hdr; 735 736 hdr = genlmsg_put(skb, NETLINK_CB(cb->skb).portid, cb->nlh->nlmsg_seq, 737 &tcp_metrics_nl_family, NLM_F_MULTI, 738 TCP_METRICS_CMD_GET); 739 if (!hdr) 740 return -EMSGSIZE; 741 742 if (tcp_metrics_fill_info(skb, tm) < 0) 743 goto nla_put_failure; 744 745 genlmsg_end(skb, hdr); 746 return 0; 747 748 nla_put_failure: 749 genlmsg_cancel(skb, hdr); 750 return -EMSGSIZE; 751 } 752 753 static int tcp_metrics_nl_dump(struct sk_buff *skb, 754 struct netlink_callback *cb) 755 { 756 struct net *net = sock_net(skb->sk); 757 unsigned int max_rows = 1U << tcp_metrics_hash_log; 758 unsigned int row, s_row = cb->args[0]; 759 int s_col = cb->args[1], col = s_col; 760 761 for (row = s_row; row < max_rows; row++, s_col = 0) { 762 struct tcp_metrics_block *tm; 763 struct tcpm_hash_bucket *hb = tcp_metrics_hash + row; 764 765 rcu_read_lock(); 766 for (col = 0, tm = rcu_dereference(hb->chain); tm; 767 tm = rcu_dereference(tm->tcpm_next), col++) { 768 if (!net_eq(tm_net(tm), net)) 769 continue; 770 if (col < s_col) 771 continue; 772 if (tcp_metrics_dump_info(skb, cb, tm) < 0) { 773 rcu_read_unlock(); 774 goto done; 775 } 776 } 777 rcu_read_unlock(); 778 } 779 780 done: 781 cb->args[0] = row; 782 cb->args[1] = col; 783 return skb->len; 784 } 785 786 static int __parse_nl_addr(struct genl_info *info, struct inetpeer_addr *addr, 787 unsigned int *hash, int optional, int v4, int v6) 788 { 789 struct nlattr *a; 790 791 a = info->attrs[v4]; 792 if (a) { 793 inetpeer_set_addr_v4(addr, nla_get_in_addr(a)); 794 if (hash) 795 *hash = ipv4_addr_hash(inetpeer_get_addr_v4(addr)); 796 return 0; 797 } 798 a = info->attrs[v6]; 799 if (a) { 800 struct in6_addr in6; 801 802 if (nla_len(a) != sizeof(struct in6_addr)) 803 return -EINVAL; 804 in6 = nla_get_in6_addr(a); 805 inetpeer_set_addr_v6(addr, &in6); 806 if (hash) 807 *hash = ipv6_addr_hash(inetpeer_get_addr_v6(addr)); 808 return 0; 809 } 810 return optional ? 1 : -EAFNOSUPPORT; 811 } 812 813 static int parse_nl_addr(struct genl_info *info, struct inetpeer_addr *addr, 814 unsigned int *hash, int optional) 815 { 816 return __parse_nl_addr(info, addr, hash, optional, 817 TCP_METRICS_ATTR_ADDR_IPV4, 818 TCP_METRICS_ATTR_ADDR_IPV6); 819 } 820 821 static int parse_nl_saddr(struct genl_info *info, struct inetpeer_addr *addr) 822 { 823 return __parse_nl_addr(info, addr, NULL, 0, 824 TCP_METRICS_ATTR_SADDR_IPV4, 825 TCP_METRICS_ATTR_SADDR_IPV6); 826 } 827 828 static int tcp_metrics_nl_cmd_get(struct sk_buff *skb, struct genl_info *info) 829 { 830 struct tcp_metrics_block *tm; 831 struct inetpeer_addr saddr, daddr; 832 unsigned int hash; 833 struct sk_buff *msg; 834 struct net *net = genl_info_net(info); 835 void *reply; 836 int ret; 837 bool src = true; 838 839 ret = parse_nl_addr(info, &daddr, &hash, 0); 840 if (ret < 0) 841 return ret; 842 843 ret = parse_nl_saddr(info, &saddr); 844 if (ret < 0) 845 src = false; 846 847 msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL); 848 if (!msg) 849 return -ENOMEM; 850 851 reply = genlmsg_put_reply(msg, info, &tcp_metrics_nl_family, 0, 852 info->genlhdr->cmd); 853 if (!reply) 854 goto nla_put_failure; 855 856 hash ^= net_hash_mix(net); 857 hash = hash_32(hash, tcp_metrics_hash_log); 858 ret = -ESRCH; 859 rcu_read_lock(); 860 for (tm = rcu_dereference(tcp_metrics_hash[hash].chain); tm; 861 tm = rcu_dereference(tm->tcpm_next)) { 862 if (addr_same(&tm->tcpm_daddr, &daddr) && 863 (!src || addr_same(&tm->tcpm_saddr, &saddr)) && 864 net_eq(tm_net(tm), net)) { 865 ret = tcp_metrics_fill_info(msg, tm); 866 break; 867 } 868 } 869 rcu_read_unlock(); 870 if (ret < 0) 871 goto out_free; 872 873 genlmsg_end(msg, reply); 874 return genlmsg_reply(msg, info); 875 876 nla_put_failure: 877 ret = -EMSGSIZE; 878 879 out_free: 880 nlmsg_free(msg); 881 return ret; 882 } 883 884 static void tcp_metrics_flush_all(struct net *net) 885 { 886 unsigned int max_rows = 1U << tcp_metrics_hash_log; 887 struct tcpm_hash_bucket *hb = tcp_metrics_hash; 888 struct tcp_metrics_block *tm; 889 unsigned int row; 890 891 for (row = 0; row < max_rows; row++, hb++) { 892 struct tcp_metrics_block __rcu **pp; 893 bool match; 894 895 spin_lock_bh(&tcp_metrics_lock); 896 pp = &hb->chain; 897 for (tm = deref_locked(*pp); tm; tm = deref_locked(*pp)) { 898 match = net ? net_eq(tm_net(tm), net) : 899 !atomic_read(&tm_net(tm)->count); 900 if (match) { 901 *pp = tm->tcpm_next; 902 kfree_rcu(tm, rcu_head); 903 } else { 904 pp = &tm->tcpm_next; 905 } 906 } 907 spin_unlock_bh(&tcp_metrics_lock); 908 } 909 } 910 911 static int tcp_metrics_nl_cmd_del(struct sk_buff *skb, struct genl_info *info) 912 { 913 struct tcpm_hash_bucket *hb; 914 struct tcp_metrics_block *tm; 915 struct tcp_metrics_block __rcu **pp; 916 struct inetpeer_addr saddr, daddr; 917 unsigned int hash; 918 struct net *net = genl_info_net(info); 919 int ret; 920 bool src = true, found = false; 921 922 ret = parse_nl_addr(info, &daddr, &hash, 1); 923 if (ret < 0) 924 return ret; 925 if (ret > 0) { 926 tcp_metrics_flush_all(net); 927 return 0; 928 } 929 ret = parse_nl_saddr(info, &saddr); 930 if (ret < 0) 931 src = false; 932 933 hash ^= net_hash_mix(net); 934 hash = hash_32(hash, tcp_metrics_hash_log); 935 hb = tcp_metrics_hash + hash; 936 pp = &hb->chain; 937 spin_lock_bh(&tcp_metrics_lock); 938 for (tm = deref_locked(*pp); tm; tm = deref_locked(*pp)) { 939 if (addr_same(&tm->tcpm_daddr, &daddr) && 940 (!src || addr_same(&tm->tcpm_saddr, &saddr)) && 941 net_eq(tm_net(tm), net)) { 942 *pp = tm->tcpm_next; 943 kfree_rcu(tm, rcu_head); 944 found = true; 945 } else { 946 pp = &tm->tcpm_next; 947 } 948 } 949 spin_unlock_bh(&tcp_metrics_lock); 950 if (!found) 951 return -ESRCH; 952 return 0; 953 } 954 955 static const struct genl_ops tcp_metrics_nl_ops[] = { 956 { 957 .cmd = TCP_METRICS_CMD_GET, 958 .doit = tcp_metrics_nl_cmd_get, 959 .dumpit = tcp_metrics_nl_dump, 960 .policy = tcp_metrics_nl_policy, 961 }, 962 { 963 .cmd = TCP_METRICS_CMD_DEL, 964 .doit = tcp_metrics_nl_cmd_del, 965 .policy = tcp_metrics_nl_policy, 966 .flags = GENL_ADMIN_PERM, 967 }, 968 }; 969 970 static struct genl_family tcp_metrics_nl_family __ro_after_init = { 971 .hdrsize = 0, 972 .name = TCP_METRICS_GENL_NAME, 973 .version = TCP_METRICS_GENL_VERSION, 974 .maxattr = TCP_METRICS_ATTR_MAX, 975 .netnsok = true, 976 .module = THIS_MODULE, 977 .ops = tcp_metrics_nl_ops, 978 .n_ops = ARRAY_SIZE(tcp_metrics_nl_ops), 979 }; 980 981 static unsigned int tcpmhash_entries; 982 static int __init set_tcpmhash_entries(char *str) 983 { 984 ssize_t ret; 985 986 if (!str) 987 return 0; 988 989 ret = kstrtouint(str, 0, &tcpmhash_entries); 990 if (ret) 991 return 0; 992 993 return 1; 994 } 995 __setup("tcpmhash_entries=", set_tcpmhash_entries); 996 997 static int __net_init tcp_net_metrics_init(struct net *net) 998 { 999 size_t size; 1000 unsigned int slots; 1001 1002 if (!net_eq(net, &init_net)) 1003 return 0; 1004 1005 slots = tcpmhash_entries; 1006 if (!slots) { 1007 if (totalram_pages >= 128 * 1024) 1008 slots = 16 * 1024; 1009 else 1010 slots = 8 * 1024; 1011 } 1012 1013 tcp_metrics_hash_log = order_base_2(slots); 1014 size = sizeof(struct tcpm_hash_bucket) << tcp_metrics_hash_log; 1015 1016 tcp_metrics_hash = kvzalloc(size, GFP_KERNEL); 1017 if (!tcp_metrics_hash) 1018 return -ENOMEM; 1019 1020 return 0; 1021 } 1022 1023 static void __net_exit tcp_net_metrics_exit_batch(struct list_head *net_exit_list) 1024 { 1025 tcp_metrics_flush_all(NULL); 1026 } 1027 1028 static __net_initdata struct pernet_operations tcp_net_metrics_ops = { 1029 .init = tcp_net_metrics_init, 1030 .exit_batch = tcp_net_metrics_exit_batch, 1031 }; 1032 1033 void __init tcp_metrics_init(void) 1034 { 1035 int ret; 1036 1037 ret = register_pernet_subsys(&tcp_net_metrics_ops); 1038 if (ret < 0) 1039 panic("Could not allocate the tcp_metrics hash table\n"); 1040 1041 ret = genl_register_family(&tcp_metrics_nl_family); 1042 if (ret < 0) 1043 panic("Could not register tcp_metrics generic netlink\n"); 1044 } 1045