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