1 // SPDX-License-Identifier: GPL-2.0 2 #include <linux/rcupdate.h> 3 #include <linux/spinlock.h> 4 #include <linux/jiffies.h> 5 #include <linux/module.h> 6 #include <linux/cache.h> 7 #include <linux/slab.h> 8 #include <linux/init.h> 9 #include <linux/tcp.h> 10 #include <linux/hash.h> 11 #include <linux/tcp_metrics.h> 12 #include <linux/vmalloc.h> 13 14 #include <net/inet_connection_sock.h> 15 #include <net/net_namespace.h> 16 #include <net/request_sock.h> 17 #include <net/inetpeer.h> 18 #include <net/sock.h> 19 #include <net/ipv6.h> 20 #include <net/dst.h> 21 #include <net/tcp.h> 22 #include <net/genetlink.h> 23 24 static struct tcp_metrics_block *__tcp_get_metrics(const struct inetpeer_addr *saddr, 25 const struct inetpeer_addr *daddr, 26 struct net *net, unsigned int hash); 27 28 struct tcp_fastopen_metrics { 29 u16 mss; 30 u16 syn_loss:10, /* Recurring Fast Open SYN losses */ 31 try_exp:2; /* Request w/ exp. option (once) */ 32 unsigned long last_syn_loss; /* Last Fast Open SYN loss */ 33 struct tcp_fastopen_cookie cookie; 34 }; 35 36 /* TCP_METRIC_MAX includes 2 extra fields for userspace compatibility 37 * Kernel only stores RTT and RTTVAR in usec resolution 38 */ 39 #define TCP_METRIC_MAX_KERNEL (TCP_METRIC_MAX - 2) 40 41 struct tcp_metrics_block { 42 struct tcp_metrics_block __rcu *tcpm_next; 43 possible_net_t tcpm_net; 44 struct inetpeer_addr tcpm_saddr; 45 struct inetpeer_addr tcpm_daddr; 46 unsigned long tcpm_stamp; 47 u32 tcpm_lock; 48 u32 tcpm_vals[TCP_METRIC_MAX_KERNEL + 1]; 49 struct tcp_fastopen_metrics tcpm_fastopen; 50 51 struct rcu_head rcu_head; 52 }; 53 54 static inline struct net *tm_net(struct tcp_metrics_block *tm) 55 { 56 return read_pnet(&tm->tcpm_net); 57 } 58 59 static bool tcp_metric_locked(struct tcp_metrics_block *tm, 60 enum tcp_metric_index idx) 61 { 62 return tm->tcpm_lock & (1 << idx); 63 } 64 65 static u32 tcp_metric_get(struct tcp_metrics_block *tm, 66 enum tcp_metric_index idx) 67 { 68 return tm->tcpm_vals[idx]; 69 } 70 71 static void tcp_metric_set(struct tcp_metrics_block *tm, 72 enum tcp_metric_index idx, 73 u32 val) 74 { 75 tm->tcpm_vals[idx] = val; 76 } 77 78 static bool addr_same(const struct inetpeer_addr *a, 79 const struct inetpeer_addr *b) 80 { 81 return inetpeer_addr_cmp(a, b) == 0; 82 } 83 84 struct tcpm_hash_bucket { 85 struct tcp_metrics_block __rcu *chain; 86 }; 87 88 static struct tcpm_hash_bucket *tcp_metrics_hash __read_mostly; 89 static unsigned int tcp_metrics_hash_log __read_mostly; 90 91 static DEFINE_SPINLOCK(tcp_metrics_lock); 92 93 static void tcpm_suck_dst(struct tcp_metrics_block *tm, 94 const struct dst_entry *dst, 95 bool fastopen_clear) 96 { 97 u32 msval; 98 u32 val; 99 100 tm->tcpm_stamp = jiffies; 101 102 val = 0; 103 if (dst_metric_locked(dst, RTAX_RTT)) 104 val |= 1 << TCP_METRIC_RTT; 105 if (dst_metric_locked(dst, RTAX_RTTVAR)) 106 val |= 1 << TCP_METRIC_RTTVAR; 107 if (dst_metric_locked(dst, RTAX_SSTHRESH)) 108 val |= 1 << TCP_METRIC_SSTHRESH; 109 if (dst_metric_locked(dst, RTAX_CWND)) 110 val |= 1 << TCP_METRIC_CWND; 111 if (dst_metric_locked(dst, RTAX_REORDERING)) 112 val |= 1 << TCP_METRIC_REORDERING; 113 tm->tcpm_lock = val; 114 115 msval = dst_metric_raw(dst, RTAX_RTT); 116 tm->tcpm_vals[TCP_METRIC_RTT] = msval * USEC_PER_MSEC; 117 118 msval = dst_metric_raw(dst, RTAX_RTTVAR); 119 tm->tcpm_vals[TCP_METRIC_RTTVAR] = msval * USEC_PER_MSEC; 120 tm->tcpm_vals[TCP_METRIC_SSTHRESH] = dst_metric_raw(dst, RTAX_SSTHRESH); 121 tm->tcpm_vals[TCP_METRIC_CWND] = dst_metric_raw(dst, RTAX_CWND); 122 tm->tcpm_vals[TCP_METRIC_REORDERING] = dst_metric_raw(dst, RTAX_REORDERING); 123 if (fastopen_clear) { 124 tm->tcpm_fastopen.mss = 0; 125 tm->tcpm_fastopen.syn_loss = 0; 126 tm->tcpm_fastopen.try_exp = 0; 127 tm->tcpm_fastopen.cookie.exp = false; 128 tm->tcpm_fastopen.cookie.len = 0; 129 } 130 } 131 132 #define TCP_METRICS_TIMEOUT (60 * 60 * HZ) 133 134 static void tcpm_check_stamp(struct tcp_metrics_block *tm, struct dst_entry *dst) 135 { 136 if (tm && unlikely(time_after(jiffies, tm->tcpm_stamp + TCP_METRICS_TIMEOUT))) 137 tcpm_suck_dst(tm, dst, false); 138 } 139 140 #define TCP_METRICS_RECLAIM_DEPTH 5 141 #define TCP_METRICS_RECLAIM_PTR (struct tcp_metrics_block *) 0x1UL 142 143 #define deref_locked(p) \ 144 rcu_dereference_protected(p, lockdep_is_held(&tcp_metrics_lock)) 145 146 static struct tcp_metrics_block *tcpm_new(struct dst_entry *dst, 147 struct inetpeer_addr *saddr, 148 struct inetpeer_addr *daddr, 149 unsigned int hash) 150 { 151 struct tcp_metrics_block *tm; 152 struct net *net; 153 bool reclaim = false; 154 155 spin_lock_bh(&tcp_metrics_lock); 156 net = dev_net(dst->dev); 157 158 /* While waiting for the spin-lock the cache might have been populated 159 * with this entry and so we have to check again. 160 */ 161 tm = __tcp_get_metrics(saddr, daddr, net, hash); 162 if (tm == TCP_METRICS_RECLAIM_PTR) { 163 reclaim = true; 164 tm = NULL; 165 } 166 if (tm) { 167 tcpm_check_stamp(tm, dst); 168 goto out_unlock; 169 } 170 171 if (unlikely(reclaim)) { 172 struct tcp_metrics_block *oldest; 173 174 oldest = deref_locked(tcp_metrics_hash[hash].chain); 175 for (tm = deref_locked(oldest->tcpm_next); tm; 176 tm = deref_locked(tm->tcpm_next)) { 177 if (time_before(tm->tcpm_stamp, oldest->tcpm_stamp)) 178 oldest = tm; 179 } 180 tm = oldest; 181 } else { 182 tm = kmalloc(sizeof(*tm), GFP_ATOMIC); 183 if (!tm) 184 goto out_unlock; 185 } 186 write_pnet(&tm->tcpm_net, net); 187 tm->tcpm_saddr = *saddr; 188 tm->tcpm_daddr = *daddr; 189 190 tcpm_suck_dst(tm, dst, true); 191 192 if (likely(!reclaim)) { 193 tm->tcpm_next = tcp_metrics_hash[hash].chain; 194 rcu_assign_pointer(tcp_metrics_hash[hash].chain, tm); 195 } 196 197 out_unlock: 198 spin_unlock_bh(&tcp_metrics_lock); 199 return tm; 200 } 201 202 static struct tcp_metrics_block *tcp_get_encode(struct tcp_metrics_block *tm, int depth) 203 { 204 if (tm) 205 return tm; 206 if (depth > TCP_METRICS_RECLAIM_DEPTH) 207 return TCP_METRICS_RECLAIM_PTR; 208 return NULL; 209 } 210 211 static struct tcp_metrics_block *__tcp_get_metrics(const struct inetpeer_addr *saddr, 212 const struct inetpeer_addr *daddr, 213 struct net *net, unsigned int hash) 214 { 215 struct tcp_metrics_block *tm; 216 int depth = 0; 217 218 for (tm = rcu_dereference(tcp_metrics_hash[hash].chain); tm; 219 tm = rcu_dereference(tm->tcpm_next)) { 220 if (addr_same(&tm->tcpm_saddr, saddr) && 221 addr_same(&tm->tcpm_daddr, daddr) && 222 net_eq(tm_net(tm), net)) 223 break; 224 depth++; 225 } 226 return tcp_get_encode(tm, depth); 227 } 228 229 static struct tcp_metrics_block *__tcp_get_metrics_req(struct request_sock *req, 230 struct dst_entry *dst) 231 { 232 struct tcp_metrics_block *tm; 233 struct inetpeer_addr saddr, daddr; 234 unsigned int hash; 235 struct net *net; 236 237 saddr.family = req->rsk_ops->family; 238 daddr.family = req->rsk_ops->family; 239 switch (daddr.family) { 240 case AF_INET: 241 inetpeer_set_addr_v4(&saddr, inet_rsk(req)->ir_loc_addr); 242 inetpeer_set_addr_v4(&daddr, inet_rsk(req)->ir_rmt_addr); 243 hash = ipv4_addr_hash(inet_rsk(req)->ir_rmt_addr); 244 break; 245 #if IS_ENABLED(CONFIG_IPV6) 246 case AF_INET6: 247 inetpeer_set_addr_v6(&saddr, &inet_rsk(req)->ir_v6_loc_addr); 248 inetpeer_set_addr_v6(&daddr, &inet_rsk(req)->ir_v6_rmt_addr); 249 hash = ipv6_addr_hash(&inet_rsk(req)->ir_v6_rmt_addr); 250 break; 251 #endif 252 default: 253 return NULL; 254 } 255 256 net = dev_net(dst->dev); 257 hash ^= net_hash_mix(net); 258 hash = hash_32(hash, tcp_metrics_hash_log); 259 260 for (tm = rcu_dereference(tcp_metrics_hash[hash].chain); tm; 261 tm = rcu_dereference(tm->tcpm_next)) { 262 if (addr_same(&tm->tcpm_saddr, &saddr) && 263 addr_same(&tm->tcpm_daddr, &daddr) && 264 net_eq(tm_net(tm), net)) 265 break; 266 } 267 tcpm_check_stamp(tm, dst); 268 return tm; 269 } 270 271 static struct tcp_metrics_block *tcp_get_metrics(struct sock *sk, 272 struct dst_entry *dst, 273 bool create) 274 { 275 struct tcp_metrics_block *tm; 276 struct inetpeer_addr saddr, daddr; 277 unsigned int hash; 278 struct net *net; 279 280 if (sk->sk_family == AF_INET) { 281 inetpeer_set_addr_v4(&saddr, inet_sk(sk)->inet_saddr); 282 inetpeer_set_addr_v4(&daddr, inet_sk(sk)->inet_daddr); 283 hash = ipv4_addr_hash(inet_sk(sk)->inet_daddr); 284 } 285 #if IS_ENABLED(CONFIG_IPV6) 286 else if (sk->sk_family == AF_INET6) { 287 if (ipv6_addr_v4mapped(&sk->sk_v6_daddr)) { 288 inetpeer_set_addr_v4(&saddr, inet_sk(sk)->inet_saddr); 289 inetpeer_set_addr_v4(&daddr, inet_sk(sk)->inet_daddr); 290 hash = ipv4_addr_hash(inet_sk(sk)->inet_daddr); 291 } else { 292 inetpeer_set_addr_v6(&saddr, &sk->sk_v6_rcv_saddr); 293 inetpeer_set_addr_v6(&daddr, &sk->sk_v6_daddr); 294 hash = ipv6_addr_hash(&sk->sk_v6_daddr); 295 } 296 } 297 #endif 298 else 299 return NULL; 300 301 net = dev_net(dst->dev); 302 hash ^= net_hash_mix(net); 303 hash = hash_32(hash, tcp_metrics_hash_log); 304 305 tm = __tcp_get_metrics(&saddr, &daddr, net, hash); 306 if (tm == TCP_METRICS_RECLAIM_PTR) 307 tm = NULL; 308 if (!tm && create) 309 tm = tcpm_new(dst, &saddr, &daddr, hash); 310 else 311 tcpm_check_stamp(tm, dst); 312 313 return tm; 314 } 315 316 /* Save metrics learned by this TCP session. This function is called 317 * only, when TCP finishes successfully i.e. when it enters TIME-WAIT 318 * or goes from LAST-ACK to CLOSE. 319 */ 320 void tcp_update_metrics(struct sock *sk) 321 { 322 const struct inet_connection_sock *icsk = inet_csk(sk); 323 struct dst_entry *dst = __sk_dst_get(sk); 324 struct tcp_sock *tp = tcp_sk(sk); 325 struct net *net = sock_net(sk); 326 struct tcp_metrics_block *tm; 327 unsigned long rtt; 328 u32 val; 329 int m; 330 331 sk_dst_confirm(sk); 332 if (net->ipv4.sysctl_tcp_nometrics_save || !dst) 333 return; 334 335 rcu_read_lock(); 336 if (icsk->icsk_backoff || !tp->srtt_us) { 337 /* This session failed to estimate rtt. Why? 338 * Probably, no packets returned in time. Reset our 339 * results. 340 */ 341 tm = tcp_get_metrics(sk, dst, false); 342 if (tm && !tcp_metric_locked(tm, TCP_METRIC_RTT)) 343 tcp_metric_set(tm, TCP_METRIC_RTT, 0); 344 goto out_unlock; 345 } else 346 tm = tcp_get_metrics(sk, dst, true); 347 348 if (!tm) 349 goto out_unlock; 350 351 rtt = tcp_metric_get(tm, TCP_METRIC_RTT); 352 m = rtt - tp->srtt_us; 353 354 /* If newly calculated rtt larger than stored one, store new 355 * one. Otherwise, use EWMA. Remember, rtt overestimation is 356 * always better than underestimation. 357 */ 358 if (!tcp_metric_locked(tm, TCP_METRIC_RTT)) { 359 if (m <= 0) 360 rtt = tp->srtt_us; 361 else 362 rtt -= (m >> 3); 363 tcp_metric_set(tm, TCP_METRIC_RTT, rtt); 364 } 365 366 if (!tcp_metric_locked(tm, TCP_METRIC_RTTVAR)) { 367 unsigned long var; 368 369 if (m < 0) 370 m = -m; 371 372 /* Scale deviation to rttvar fixed point */ 373 m >>= 1; 374 if (m < tp->mdev_us) 375 m = tp->mdev_us; 376 377 var = tcp_metric_get(tm, TCP_METRIC_RTTVAR); 378 if (m >= var) 379 var = m; 380 else 381 var -= (var - m) >> 2; 382 383 tcp_metric_set(tm, TCP_METRIC_RTTVAR, var); 384 } 385 386 if (tcp_in_initial_slowstart(tp)) { 387 /* Slow start still did not finish. */ 388 if (!net->ipv4.sysctl_tcp_no_ssthresh_metrics_save && 389 !tcp_metric_locked(tm, TCP_METRIC_SSTHRESH)) { 390 val = tcp_metric_get(tm, TCP_METRIC_SSTHRESH); 391 if (val && (tcp_snd_cwnd(tp) >> 1) > val) 392 tcp_metric_set(tm, TCP_METRIC_SSTHRESH, 393 tcp_snd_cwnd(tp) >> 1); 394 } 395 if (!tcp_metric_locked(tm, TCP_METRIC_CWND)) { 396 val = tcp_metric_get(tm, TCP_METRIC_CWND); 397 if (tcp_snd_cwnd(tp) > val) 398 tcp_metric_set(tm, TCP_METRIC_CWND, 399 tcp_snd_cwnd(tp)); 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 (!net->ipv4.sysctl_tcp_no_ssthresh_metrics_save && 405 !tcp_metric_locked(tm, TCP_METRIC_SSTHRESH)) 406 tcp_metric_set(tm, TCP_METRIC_SSTHRESH, 407 max(tcp_snd_cwnd(tp) >> 1, tp->snd_ssthresh)); 408 if (!tcp_metric_locked(tm, TCP_METRIC_CWND)) { 409 val = tcp_metric_get(tm, TCP_METRIC_CWND); 410 tcp_metric_set(tm, TCP_METRIC_CWND, (val + tcp_snd_cwnd(tp)) >> 1); 411 } 412 } else { 413 /* Else slow start did not finish, cwnd is non-sense, 414 * ssthresh may be also invalid. 415 */ 416 if (!tcp_metric_locked(tm, TCP_METRIC_CWND)) { 417 val = tcp_metric_get(tm, TCP_METRIC_CWND); 418 tcp_metric_set(tm, TCP_METRIC_CWND, 419 (val + tp->snd_ssthresh) >> 1); 420 } 421 if (!net->ipv4.sysctl_tcp_no_ssthresh_metrics_save && 422 !tcp_metric_locked(tm, TCP_METRIC_SSTHRESH)) { 423 val = tcp_metric_get(tm, TCP_METRIC_SSTHRESH); 424 if (val && tp->snd_ssthresh > val) 425 tcp_metric_set(tm, TCP_METRIC_SSTHRESH, 426 tp->snd_ssthresh); 427 } 428 if (!tcp_metric_locked(tm, TCP_METRIC_REORDERING)) { 429 val = tcp_metric_get(tm, TCP_METRIC_REORDERING); 430 if (val < tp->reordering && 431 tp->reordering != net->ipv4.sysctl_tcp_reordering) 432 tcp_metric_set(tm, TCP_METRIC_REORDERING, 433 tp->reordering); 434 } 435 } 436 tm->tcpm_stamp = jiffies; 437 out_unlock: 438 rcu_read_unlock(); 439 } 440 441 /* Initialize metrics on socket. */ 442 443 void tcp_init_metrics(struct sock *sk) 444 { 445 struct dst_entry *dst = __sk_dst_get(sk); 446 struct tcp_sock *tp = tcp_sk(sk); 447 struct net *net = sock_net(sk); 448 struct tcp_metrics_block *tm; 449 u32 val, crtt = 0; /* cached RTT scaled by 8 */ 450 451 sk_dst_confirm(sk); 452 if (!dst) 453 goto reset; 454 455 rcu_read_lock(); 456 tm = tcp_get_metrics(sk, dst, true); 457 if (!tm) { 458 rcu_read_unlock(); 459 goto reset; 460 } 461 462 if (tcp_metric_locked(tm, TCP_METRIC_CWND)) 463 tp->snd_cwnd_clamp = tcp_metric_get(tm, TCP_METRIC_CWND); 464 465 val = net->ipv4.sysctl_tcp_no_ssthresh_metrics_save ? 466 0 : tcp_metric_get(tm, TCP_METRIC_SSTHRESH); 467 if (val) { 468 tp->snd_ssthresh = val; 469 if (tp->snd_ssthresh > tp->snd_cwnd_clamp) 470 tp->snd_ssthresh = tp->snd_cwnd_clamp; 471 } else { 472 /* ssthresh may have been reduced unnecessarily during. 473 * 3WHS. Restore it back to its initial default. 474 */ 475 tp->snd_ssthresh = TCP_INFINITE_SSTHRESH; 476 } 477 val = tcp_metric_get(tm, TCP_METRIC_REORDERING); 478 if (val && tp->reordering != val) 479 tp->reordering = val; 480 481 crtt = tcp_metric_get(tm, TCP_METRIC_RTT); 482 rcu_read_unlock(); 483 reset: 484 /* The initial RTT measurement from the SYN/SYN-ACK is not ideal 485 * to seed the RTO for later data packets because SYN packets are 486 * small. Use the per-dst cached values to seed the RTO but keep 487 * the RTT estimator variables intact (e.g., srtt, mdev, rttvar). 488 * Later the RTO will be updated immediately upon obtaining the first 489 * data RTT sample (tcp_rtt_estimator()). Hence the cached RTT only 490 * influences the first RTO but not later RTT estimation. 491 * 492 * But if RTT is not available from the SYN (due to retransmits or 493 * syn cookies) or the cache, force a conservative 3secs timeout. 494 * 495 * A bit of theory. RTT is time passed after "normal" sized packet 496 * is sent until it is ACKed. In normal circumstances sending small 497 * packets force peer to delay ACKs and calculation is correct too. 498 * The algorithm is adaptive and, provided we follow specs, it 499 * NEVER underestimate RTT. BUT! If peer tries to make some clever 500 * tricks sort of "quick acks" for time long enough to decrease RTT 501 * to low value, and then abruptly stops to do it and starts to delay 502 * ACKs, wait for troubles. 503 */ 504 if (crtt > tp->srtt_us) { 505 /* Set RTO like tcp_rtt_estimator(), but from cached RTT. */ 506 crtt /= 8 * USEC_PER_SEC / HZ; 507 inet_csk(sk)->icsk_rto = crtt + max(2 * crtt, tcp_rto_min(sk)); 508 } else if (tp->srtt_us == 0) { 509 /* RFC6298: 5.7 We've failed to get a valid RTT sample from 510 * 3WHS. This is most likely due to retransmission, 511 * including spurious one. Reset the RTO back to 3secs 512 * from the more aggressive 1sec to avoid more spurious 513 * retransmission. 514 */ 515 tp->rttvar_us = jiffies_to_usecs(TCP_TIMEOUT_FALLBACK); 516 tp->mdev_us = tp->mdev_max_us = tp->rttvar_us; 517 518 inet_csk(sk)->icsk_rto = TCP_TIMEOUT_FALLBACK; 519 } 520 } 521 522 bool tcp_peer_is_proven(struct request_sock *req, struct dst_entry *dst) 523 { 524 struct tcp_metrics_block *tm; 525 bool ret; 526 527 if (!dst) 528 return false; 529 530 rcu_read_lock(); 531 tm = __tcp_get_metrics_req(req, dst); 532 if (tm && tcp_metric_get(tm, TCP_METRIC_RTT)) 533 ret = true; 534 else 535 ret = false; 536 rcu_read_unlock(); 537 538 return ret; 539 } 540 541 static DEFINE_SEQLOCK(fastopen_seqlock); 542 543 void tcp_fastopen_cache_get(struct sock *sk, u16 *mss, 544 struct tcp_fastopen_cookie *cookie) 545 { 546 struct tcp_metrics_block *tm; 547 548 rcu_read_lock(); 549 tm = tcp_get_metrics(sk, __sk_dst_get(sk), false); 550 if (tm) { 551 struct tcp_fastopen_metrics *tfom = &tm->tcpm_fastopen; 552 unsigned int seq; 553 554 do { 555 seq = read_seqbegin(&fastopen_seqlock); 556 if (tfom->mss) 557 *mss = tfom->mss; 558 *cookie = tfom->cookie; 559 if (cookie->len <= 0 && tfom->try_exp == 1) 560 cookie->exp = true; 561 } while (read_seqretry(&fastopen_seqlock, seq)); 562 } 563 rcu_read_unlock(); 564 } 565 566 void tcp_fastopen_cache_set(struct sock *sk, u16 mss, 567 struct tcp_fastopen_cookie *cookie, bool syn_lost, 568 u16 try_exp) 569 { 570 struct dst_entry *dst = __sk_dst_get(sk); 571 struct tcp_metrics_block *tm; 572 573 if (!dst) 574 return; 575 rcu_read_lock(); 576 tm = tcp_get_metrics(sk, dst, true); 577 if (tm) { 578 struct tcp_fastopen_metrics *tfom = &tm->tcpm_fastopen; 579 580 write_seqlock_bh(&fastopen_seqlock); 581 if (mss) 582 tfom->mss = mss; 583 if (cookie && cookie->len > 0) 584 tfom->cookie = *cookie; 585 else if (try_exp > tfom->try_exp && 586 tfom->cookie.len <= 0 && !tfom->cookie.exp) 587 tfom->try_exp = try_exp; 588 if (syn_lost) { 589 ++tfom->syn_loss; 590 tfom->last_syn_loss = jiffies; 591 } else 592 tfom->syn_loss = 0; 593 write_sequnlock_bh(&fastopen_seqlock); 594 } 595 rcu_read_unlock(); 596 } 597 598 static struct genl_family tcp_metrics_nl_family; 599 600 static const struct nla_policy tcp_metrics_nl_policy[TCP_METRICS_ATTR_MAX + 1] = { 601 [TCP_METRICS_ATTR_ADDR_IPV4] = { .type = NLA_U32, }, 602 [TCP_METRICS_ATTR_ADDR_IPV6] = { .type = NLA_BINARY, 603 .len = sizeof(struct in6_addr), }, 604 /* Following attributes are not received for GET/DEL, 605 * we keep them for reference 606 */ 607 #if 0 608 [TCP_METRICS_ATTR_AGE] = { .type = NLA_MSECS, }, 609 [TCP_METRICS_ATTR_TW_TSVAL] = { .type = NLA_U32, }, 610 [TCP_METRICS_ATTR_TW_TS_STAMP] = { .type = NLA_S32, }, 611 [TCP_METRICS_ATTR_VALS] = { .type = NLA_NESTED, }, 612 [TCP_METRICS_ATTR_FOPEN_MSS] = { .type = NLA_U16, }, 613 [TCP_METRICS_ATTR_FOPEN_SYN_DROPS] = { .type = NLA_U16, }, 614 [TCP_METRICS_ATTR_FOPEN_SYN_DROP_TS] = { .type = NLA_MSECS, }, 615 [TCP_METRICS_ATTR_FOPEN_COOKIE] = { .type = NLA_BINARY, 616 .len = TCP_FASTOPEN_COOKIE_MAX, }, 617 #endif 618 }; 619 620 /* Add attributes, caller cancels its header on failure */ 621 static int tcp_metrics_fill_info(struct sk_buff *msg, 622 struct tcp_metrics_block *tm) 623 { 624 struct nlattr *nest; 625 int i; 626 627 switch (tm->tcpm_daddr.family) { 628 case AF_INET: 629 if (nla_put_in_addr(msg, TCP_METRICS_ATTR_ADDR_IPV4, 630 inetpeer_get_addr_v4(&tm->tcpm_daddr)) < 0) 631 goto nla_put_failure; 632 if (nla_put_in_addr(msg, TCP_METRICS_ATTR_SADDR_IPV4, 633 inetpeer_get_addr_v4(&tm->tcpm_saddr)) < 0) 634 goto nla_put_failure; 635 break; 636 case AF_INET6: 637 if (nla_put_in6_addr(msg, TCP_METRICS_ATTR_ADDR_IPV6, 638 inetpeer_get_addr_v6(&tm->tcpm_daddr)) < 0) 639 goto nla_put_failure; 640 if (nla_put_in6_addr(msg, TCP_METRICS_ATTR_SADDR_IPV6, 641 inetpeer_get_addr_v6(&tm->tcpm_saddr)) < 0) 642 goto nla_put_failure; 643 break; 644 default: 645 return -EAFNOSUPPORT; 646 } 647 648 if (nla_put_msecs(msg, TCP_METRICS_ATTR_AGE, 649 jiffies - tm->tcpm_stamp, 650 TCP_METRICS_ATTR_PAD) < 0) 651 goto nla_put_failure; 652 653 { 654 int n = 0; 655 656 nest = nla_nest_start_noflag(msg, TCP_METRICS_ATTR_VALS); 657 if (!nest) 658 goto nla_put_failure; 659 for (i = 0; i < TCP_METRIC_MAX_KERNEL + 1; i++) { 660 u32 val = tm->tcpm_vals[i]; 661 662 if (!val) 663 continue; 664 if (i == TCP_METRIC_RTT) { 665 if (nla_put_u32(msg, TCP_METRIC_RTT_US + 1, 666 val) < 0) 667 goto nla_put_failure; 668 n++; 669 val = max(val / 1000, 1U); 670 } 671 if (i == TCP_METRIC_RTTVAR) { 672 if (nla_put_u32(msg, TCP_METRIC_RTTVAR_US + 1, 673 val) < 0) 674 goto nla_put_failure; 675 n++; 676 val = max(val / 1000, 1U); 677 } 678 if (nla_put_u32(msg, i + 1, val) < 0) 679 goto nla_put_failure; 680 n++; 681 } 682 if (n) 683 nla_nest_end(msg, nest); 684 else 685 nla_nest_cancel(msg, nest); 686 } 687 688 { 689 struct tcp_fastopen_metrics tfom_copy[1], *tfom; 690 unsigned int seq; 691 692 do { 693 seq = read_seqbegin(&fastopen_seqlock); 694 tfom_copy[0] = tm->tcpm_fastopen; 695 } while (read_seqretry(&fastopen_seqlock, seq)); 696 697 tfom = tfom_copy; 698 if (tfom->mss && 699 nla_put_u16(msg, TCP_METRICS_ATTR_FOPEN_MSS, 700 tfom->mss) < 0) 701 goto nla_put_failure; 702 if (tfom->syn_loss && 703 (nla_put_u16(msg, TCP_METRICS_ATTR_FOPEN_SYN_DROPS, 704 tfom->syn_loss) < 0 || 705 nla_put_msecs(msg, TCP_METRICS_ATTR_FOPEN_SYN_DROP_TS, 706 jiffies - tfom->last_syn_loss, 707 TCP_METRICS_ATTR_PAD) < 0)) 708 goto nla_put_failure; 709 if (tfom->cookie.len > 0 && 710 nla_put(msg, TCP_METRICS_ATTR_FOPEN_COOKIE, 711 tfom->cookie.len, tfom->cookie.val) < 0) 712 goto nla_put_failure; 713 } 714 715 return 0; 716 717 nla_put_failure: 718 return -EMSGSIZE; 719 } 720 721 static int tcp_metrics_dump_info(struct sk_buff *skb, 722 struct netlink_callback *cb, 723 struct tcp_metrics_block *tm) 724 { 725 void *hdr; 726 727 hdr = genlmsg_put(skb, NETLINK_CB(cb->skb).portid, cb->nlh->nlmsg_seq, 728 &tcp_metrics_nl_family, NLM_F_MULTI, 729 TCP_METRICS_CMD_GET); 730 if (!hdr) 731 return -EMSGSIZE; 732 733 if (tcp_metrics_fill_info(skb, tm) < 0) 734 goto nla_put_failure; 735 736 genlmsg_end(skb, hdr); 737 return 0; 738 739 nla_put_failure: 740 genlmsg_cancel(skb, hdr); 741 return -EMSGSIZE; 742 } 743 744 static int tcp_metrics_nl_dump(struct sk_buff *skb, 745 struct netlink_callback *cb) 746 { 747 struct net *net = sock_net(skb->sk); 748 unsigned int max_rows = 1U << tcp_metrics_hash_log; 749 unsigned int row, s_row = cb->args[0]; 750 int s_col = cb->args[1], col = s_col; 751 752 for (row = s_row; row < max_rows; row++, s_col = 0) { 753 struct tcp_metrics_block *tm; 754 struct tcpm_hash_bucket *hb = tcp_metrics_hash + row; 755 756 rcu_read_lock(); 757 for (col = 0, tm = rcu_dereference(hb->chain); tm; 758 tm = rcu_dereference(tm->tcpm_next), col++) { 759 if (!net_eq(tm_net(tm), net)) 760 continue; 761 if (col < s_col) 762 continue; 763 if (tcp_metrics_dump_info(skb, cb, tm) < 0) { 764 rcu_read_unlock(); 765 goto done; 766 } 767 } 768 rcu_read_unlock(); 769 } 770 771 done: 772 cb->args[0] = row; 773 cb->args[1] = col; 774 return skb->len; 775 } 776 777 static int __parse_nl_addr(struct genl_info *info, struct inetpeer_addr *addr, 778 unsigned int *hash, int optional, int v4, int v6) 779 { 780 struct nlattr *a; 781 782 a = info->attrs[v4]; 783 if (a) { 784 inetpeer_set_addr_v4(addr, nla_get_in_addr(a)); 785 if (hash) 786 *hash = ipv4_addr_hash(inetpeer_get_addr_v4(addr)); 787 return 0; 788 } 789 a = info->attrs[v6]; 790 if (a) { 791 struct in6_addr in6; 792 793 if (nla_len(a) != sizeof(struct in6_addr)) 794 return -EINVAL; 795 in6 = nla_get_in6_addr(a); 796 inetpeer_set_addr_v6(addr, &in6); 797 if (hash) 798 *hash = ipv6_addr_hash(inetpeer_get_addr_v6(addr)); 799 return 0; 800 } 801 return optional ? 1 : -EAFNOSUPPORT; 802 } 803 804 static int parse_nl_addr(struct genl_info *info, struct inetpeer_addr *addr, 805 unsigned int *hash, int optional) 806 { 807 return __parse_nl_addr(info, addr, hash, optional, 808 TCP_METRICS_ATTR_ADDR_IPV4, 809 TCP_METRICS_ATTR_ADDR_IPV6); 810 } 811 812 static int parse_nl_saddr(struct genl_info *info, struct inetpeer_addr *addr) 813 { 814 return __parse_nl_addr(info, addr, NULL, 0, 815 TCP_METRICS_ATTR_SADDR_IPV4, 816 TCP_METRICS_ATTR_SADDR_IPV6); 817 } 818 819 static int tcp_metrics_nl_cmd_get(struct sk_buff *skb, struct genl_info *info) 820 { 821 struct tcp_metrics_block *tm; 822 struct inetpeer_addr saddr, daddr; 823 unsigned int hash; 824 struct sk_buff *msg; 825 struct net *net = genl_info_net(info); 826 void *reply; 827 int ret; 828 bool src = true; 829 830 ret = parse_nl_addr(info, &daddr, &hash, 0); 831 if (ret < 0) 832 return ret; 833 834 ret = parse_nl_saddr(info, &saddr); 835 if (ret < 0) 836 src = false; 837 838 msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL); 839 if (!msg) 840 return -ENOMEM; 841 842 reply = genlmsg_put_reply(msg, info, &tcp_metrics_nl_family, 0, 843 info->genlhdr->cmd); 844 if (!reply) 845 goto nla_put_failure; 846 847 hash ^= net_hash_mix(net); 848 hash = hash_32(hash, tcp_metrics_hash_log); 849 ret = -ESRCH; 850 rcu_read_lock(); 851 for (tm = rcu_dereference(tcp_metrics_hash[hash].chain); tm; 852 tm = rcu_dereference(tm->tcpm_next)) { 853 if (addr_same(&tm->tcpm_daddr, &daddr) && 854 (!src || addr_same(&tm->tcpm_saddr, &saddr)) && 855 net_eq(tm_net(tm), net)) { 856 ret = tcp_metrics_fill_info(msg, tm); 857 break; 858 } 859 } 860 rcu_read_unlock(); 861 if (ret < 0) 862 goto out_free; 863 864 genlmsg_end(msg, reply); 865 return genlmsg_reply(msg, info); 866 867 nla_put_failure: 868 ret = -EMSGSIZE; 869 870 out_free: 871 nlmsg_free(msg); 872 return ret; 873 } 874 875 static void tcp_metrics_flush_all(struct net *net) 876 { 877 unsigned int max_rows = 1U << tcp_metrics_hash_log; 878 struct tcpm_hash_bucket *hb = tcp_metrics_hash; 879 struct tcp_metrics_block *tm; 880 unsigned int row; 881 882 for (row = 0; row < max_rows; row++, hb++) { 883 struct tcp_metrics_block __rcu **pp; 884 bool match; 885 886 spin_lock_bh(&tcp_metrics_lock); 887 pp = &hb->chain; 888 for (tm = deref_locked(*pp); tm; tm = deref_locked(*pp)) { 889 match = net ? net_eq(tm_net(tm), net) : 890 !refcount_read(&tm_net(tm)->ns.count); 891 if (match) { 892 *pp = tm->tcpm_next; 893 kfree_rcu(tm, rcu_head); 894 } else { 895 pp = &tm->tcpm_next; 896 } 897 } 898 spin_unlock_bh(&tcp_metrics_lock); 899 } 900 } 901 902 static int tcp_metrics_nl_cmd_del(struct sk_buff *skb, struct genl_info *info) 903 { 904 struct tcpm_hash_bucket *hb; 905 struct tcp_metrics_block *tm; 906 struct tcp_metrics_block __rcu **pp; 907 struct inetpeer_addr saddr, daddr; 908 unsigned int hash; 909 struct net *net = genl_info_net(info); 910 int ret; 911 bool src = true, found = false; 912 913 ret = parse_nl_addr(info, &daddr, &hash, 1); 914 if (ret < 0) 915 return ret; 916 if (ret > 0) { 917 tcp_metrics_flush_all(net); 918 return 0; 919 } 920 ret = parse_nl_saddr(info, &saddr); 921 if (ret < 0) 922 src = false; 923 924 hash ^= net_hash_mix(net); 925 hash = hash_32(hash, tcp_metrics_hash_log); 926 hb = tcp_metrics_hash + hash; 927 pp = &hb->chain; 928 spin_lock_bh(&tcp_metrics_lock); 929 for (tm = deref_locked(*pp); tm; tm = deref_locked(*pp)) { 930 if (addr_same(&tm->tcpm_daddr, &daddr) && 931 (!src || addr_same(&tm->tcpm_saddr, &saddr)) && 932 net_eq(tm_net(tm), net)) { 933 *pp = tm->tcpm_next; 934 kfree_rcu(tm, rcu_head); 935 found = true; 936 } else { 937 pp = &tm->tcpm_next; 938 } 939 } 940 spin_unlock_bh(&tcp_metrics_lock); 941 if (!found) 942 return -ESRCH; 943 return 0; 944 } 945 946 static const struct genl_small_ops tcp_metrics_nl_ops[] = { 947 { 948 .cmd = TCP_METRICS_CMD_GET, 949 .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP, 950 .doit = tcp_metrics_nl_cmd_get, 951 .dumpit = tcp_metrics_nl_dump, 952 }, 953 { 954 .cmd = TCP_METRICS_CMD_DEL, 955 .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP, 956 .doit = tcp_metrics_nl_cmd_del, 957 .flags = GENL_ADMIN_PERM, 958 }, 959 }; 960 961 static struct genl_family tcp_metrics_nl_family __ro_after_init = { 962 .hdrsize = 0, 963 .name = TCP_METRICS_GENL_NAME, 964 .version = TCP_METRICS_GENL_VERSION, 965 .maxattr = TCP_METRICS_ATTR_MAX, 966 .policy = tcp_metrics_nl_policy, 967 .netnsok = true, 968 .module = THIS_MODULE, 969 .small_ops = tcp_metrics_nl_ops, 970 .n_small_ops = ARRAY_SIZE(tcp_metrics_nl_ops), 971 }; 972 973 static unsigned int tcpmhash_entries; 974 static int __init set_tcpmhash_entries(char *str) 975 { 976 ssize_t ret; 977 978 if (!str) 979 return 0; 980 981 ret = kstrtouint(str, 0, &tcpmhash_entries); 982 if (ret) 983 return 0; 984 985 return 1; 986 } 987 __setup("tcpmhash_entries=", set_tcpmhash_entries); 988 989 static int __net_init tcp_net_metrics_init(struct net *net) 990 { 991 size_t size; 992 unsigned int slots; 993 994 if (!net_eq(net, &init_net)) 995 return 0; 996 997 slots = tcpmhash_entries; 998 if (!slots) { 999 if (totalram_pages() >= 128 * 1024) 1000 slots = 16 * 1024; 1001 else 1002 slots = 8 * 1024; 1003 } 1004 1005 tcp_metrics_hash_log = order_base_2(slots); 1006 size = sizeof(struct tcpm_hash_bucket) << tcp_metrics_hash_log; 1007 1008 tcp_metrics_hash = kvzalloc(size, GFP_KERNEL); 1009 if (!tcp_metrics_hash) 1010 return -ENOMEM; 1011 1012 return 0; 1013 } 1014 1015 static void __net_exit tcp_net_metrics_exit_batch(struct list_head *net_exit_list) 1016 { 1017 tcp_metrics_flush_all(NULL); 1018 } 1019 1020 static __net_initdata struct pernet_operations tcp_net_metrics_ops = { 1021 .init = tcp_net_metrics_init, 1022 .exit_batch = tcp_net_metrics_exit_batch, 1023 }; 1024 1025 void __init tcp_metrics_init(void) 1026 { 1027 int ret; 1028 1029 ret = register_pernet_subsys(&tcp_net_metrics_ops); 1030 if (ret < 0) 1031 panic("Could not allocate the tcp_metrics hash table\n"); 1032 1033 ret = genl_register_family(&tcp_metrics_nl_family); 1034 if (ret < 0) 1035 panic("Could not register tcp_metrics generic netlink\n"); 1036 } 1037