linux/net/ipv4/tcp_metrics.c
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   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
  23int sysctl_tcp_nometrics_save __read_mostly;
  24
  25struct tcp_fastopen_metrics {
  26        u16     mss;
  27        u16     syn_loss:10;            /* Recurring Fast Open SYN losses */
  28        unsigned long   last_syn_loss;  /* Last Fast Open SYN loss */
  29        struct  tcp_fastopen_cookie     cookie;
  30};
  31
  32struct tcp_metrics_block {
  33        struct tcp_metrics_block __rcu  *tcpm_next;
  34        struct inetpeer_addr            tcpm_addr;
  35        unsigned long                   tcpm_stamp;
  36        u32                             tcpm_ts;
  37        u32                             tcpm_ts_stamp;
  38        u32                             tcpm_lock;
  39        u32                             tcpm_vals[TCP_METRIC_MAX + 1];
  40        struct tcp_fastopen_metrics     tcpm_fastopen;
  41
  42        struct rcu_head                 rcu_head;
  43};
  44
  45static bool tcp_metric_locked(struct tcp_metrics_block *tm,
  46                              enum tcp_metric_index idx)
  47{
  48        return tm->tcpm_lock & (1 << idx);
  49}
  50
  51static u32 tcp_metric_get(struct tcp_metrics_block *tm,
  52                          enum tcp_metric_index idx)
  53{
  54        return tm->tcpm_vals[idx];
  55}
  56
  57static u32 tcp_metric_get_jiffies(struct tcp_metrics_block *tm,
  58                                  enum tcp_metric_index idx)
  59{
  60        return msecs_to_jiffies(tm->tcpm_vals[idx]);
  61}
  62
  63static void tcp_metric_set(struct tcp_metrics_block *tm,
  64                           enum tcp_metric_index idx,
  65                           u32 val)
  66{
  67        tm->tcpm_vals[idx] = val;
  68}
  69
  70static void tcp_metric_set_msecs(struct tcp_metrics_block *tm,
  71                                 enum tcp_metric_index idx,
  72                                 u32 val)
  73{
  74        tm->tcpm_vals[idx] = jiffies_to_msecs(val);
  75}
  76
  77static bool addr_same(const struct inetpeer_addr *a,
  78                      const struct inetpeer_addr *b)
  79{
  80        const struct in6_addr *a6, *b6;
  81
  82        if (a->family != b->family)
  83                return false;
  84        if (a->family == AF_INET)
  85                return a->addr.a4 == b->addr.a4;
  86
  87        a6 = (const struct in6_addr *) &a->addr.a6[0];
  88        b6 = (const struct in6_addr *) &b->addr.a6[0];
  89
  90        return ipv6_addr_equal(a6, b6);
  91}
  92
  93struct tcpm_hash_bucket {
  94        struct tcp_metrics_block __rcu  *chain;
  95};
  96
  97static DEFINE_SPINLOCK(tcp_metrics_lock);
  98
  99static void tcpm_suck_dst(struct tcp_metrics_block *tm, struct dst_entry *dst)
 100{
 101        u32 val;
 102
 103        tm->tcpm_stamp = jiffies;
 104
 105        val = 0;
 106        if (dst_metric_locked(dst, RTAX_RTT))
 107                val |= 1 << TCP_METRIC_RTT;
 108        if (dst_metric_locked(dst, RTAX_RTTVAR))
 109                val |= 1 << TCP_METRIC_RTTVAR;
 110        if (dst_metric_locked(dst, RTAX_SSTHRESH))
 111                val |= 1 << TCP_METRIC_SSTHRESH;
 112        if (dst_metric_locked(dst, RTAX_CWND))
 113                val |= 1 << TCP_METRIC_CWND;
 114        if (dst_metric_locked(dst, RTAX_REORDERING))
 115                val |= 1 << TCP_METRIC_REORDERING;
 116        tm->tcpm_lock = val;
 117
 118        tm->tcpm_vals[TCP_METRIC_RTT] = dst_metric_raw(dst, RTAX_RTT);
 119        tm->tcpm_vals[TCP_METRIC_RTTVAR] = dst_metric_raw(dst, RTAX_RTTVAR);
 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        tm->tcpm_ts = 0;
 124        tm->tcpm_ts_stamp = 0;
 125        tm->tcpm_fastopen.mss = 0;
 126        tm->tcpm_fastopen.syn_loss = 0;
 127        tm->tcpm_fastopen.cookie.len = 0;
 128}
 129
 130static struct tcp_metrics_block *tcpm_new(struct dst_entry *dst,
 131                                          struct inetpeer_addr *addr,
 132                                          unsigned int hash,
 133                                          bool reclaim)
 134{
 135        struct tcp_metrics_block *tm;
 136        struct net *net;
 137
 138        spin_lock_bh(&tcp_metrics_lock);
 139        net = dev_net(dst->dev);
 140        if (unlikely(reclaim)) {
 141                struct tcp_metrics_block *oldest;
 142
 143                oldest = rcu_dereference(net->ipv4.tcp_metrics_hash[hash].chain);
 144                for (tm = rcu_dereference(oldest->tcpm_next); tm;
 145                     tm = rcu_dereference(tm->tcpm_next)) {
 146                        if (time_before(tm->tcpm_stamp, oldest->tcpm_stamp))
 147                                oldest = tm;
 148                }
 149                tm = oldest;
 150        } else {
 151                tm = kmalloc(sizeof(*tm), GFP_ATOMIC);
 152                if (!tm)
 153                        goto out_unlock;
 154        }
 155        tm->tcpm_addr = *addr;
 156
 157        tcpm_suck_dst(tm, dst);
 158
 159        if (likely(!reclaim)) {
 160                tm->tcpm_next = net->ipv4.tcp_metrics_hash[hash].chain;
 161                rcu_assign_pointer(net->ipv4.tcp_metrics_hash[hash].chain, tm);
 162        }
 163
 164out_unlock:
 165        spin_unlock_bh(&tcp_metrics_lock);
 166        return tm;
 167}
 168
 169#define TCP_METRICS_TIMEOUT             (60 * 60 * HZ)
 170
 171static void tcpm_check_stamp(struct tcp_metrics_block *tm, struct dst_entry *dst)
 172{
 173        if (tm && unlikely(time_after(jiffies, tm->tcpm_stamp + TCP_METRICS_TIMEOUT)))
 174                tcpm_suck_dst(tm, dst);
 175}
 176
 177#define TCP_METRICS_RECLAIM_DEPTH       5
 178#define TCP_METRICS_RECLAIM_PTR         (struct tcp_metrics_block *) 0x1UL
 179
 180static struct tcp_metrics_block *tcp_get_encode(struct tcp_metrics_block *tm, int depth)
 181{
 182        if (tm)
 183                return tm;
 184        if (depth > TCP_METRICS_RECLAIM_DEPTH)
 185                return TCP_METRICS_RECLAIM_PTR;
 186        return NULL;
 187}
 188
 189static struct tcp_metrics_block *__tcp_get_metrics(const struct inetpeer_addr *addr,
 190                                                   struct net *net, unsigned int hash)
 191{
 192        struct tcp_metrics_block *tm;
 193        int depth = 0;
 194
 195        for (tm = rcu_dereference(net->ipv4.tcp_metrics_hash[hash].chain); tm;
 196             tm = rcu_dereference(tm->tcpm_next)) {
 197                if (addr_same(&tm->tcpm_addr, addr))
 198                        break;
 199                depth++;
 200        }
 201        return tcp_get_encode(tm, depth);
 202}
 203
 204static struct tcp_metrics_block *__tcp_get_metrics_req(struct request_sock *req,
 205                                                       struct dst_entry *dst)
 206{
 207        struct tcp_metrics_block *tm;
 208        struct inetpeer_addr addr;
 209        unsigned int hash;
 210        struct net *net;
 211
 212        addr.family = req->rsk_ops->family;
 213        switch (addr.family) {
 214        case AF_INET:
 215                addr.addr.a4 = inet_rsk(req)->rmt_addr;
 216                hash = (__force unsigned int) addr.addr.a4;
 217                break;
 218        case AF_INET6:
 219                *(struct in6_addr *)addr.addr.a6 = inet6_rsk(req)->rmt_addr;
 220                hash = ipv6_addr_hash(&inet6_rsk(req)->rmt_addr);
 221                break;
 222        default:
 223                return NULL;
 224        }
 225
 226        net = dev_net(dst->dev);
 227        hash = hash_32(hash, net->ipv4.tcp_metrics_hash_log);
 228
 229        for (tm = rcu_dereference(net->ipv4.tcp_metrics_hash[hash].chain); tm;
 230             tm = rcu_dereference(tm->tcpm_next)) {
 231                if (addr_same(&tm->tcpm_addr, &addr))
 232                        break;
 233        }
 234        tcpm_check_stamp(tm, dst);
 235        return tm;
 236}
 237
 238static struct tcp_metrics_block *__tcp_get_metrics_tw(struct inet_timewait_sock *tw)
 239{
 240        struct inet6_timewait_sock *tw6;
 241        struct tcp_metrics_block *tm;
 242        struct inetpeer_addr addr;
 243        unsigned int hash;
 244        struct net *net;
 245
 246        addr.family = tw->tw_family;
 247        switch (addr.family) {
 248        case AF_INET:
 249                addr.addr.a4 = tw->tw_daddr;
 250                hash = (__force unsigned int) addr.addr.a4;
 251                break;
 252        case AF_INET6:
 253                tw6 = inet6_twsk((struct sock *)tw);
 254                *(struct in6_addr *)addr.addr.a6 = tw6->tw_v6_daddr;
 255                hash = ipv6_addr_hash(&tw6->tw_v6_daddr);
 256                break;
 257        default:
 258                return NULL;
 259        }
 260
 261        net = twsk_net(tw);
 262        hash = hash_32(hash, net->ipv4.tcp_metrics_hash_log);
 263
 264        for (tm = rcu_dereference(net->ipv4.tcp_metrics_hash[hash].chain); tm;
 265             tm = rcu_dereference(tm->tcpm_next)) {
 266                if (addr_same(&tm->tcpm_addr, &addr))
 267                        break;
 268        }
 269        return tm;
 270}
 271
 272static 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 addr;
 278        unsigned int hash;
 279        struct net *net;
 280        bool reclaim;
 281
 282        addr.family = sk->sk_family;
 283        switch (addr.family) {
 284        case AF_INET:
 285                addr.addr.a4 = inet_sk(sk)->inet_daddr;
 286                hash = (__force unsigned int) addr.addr.a4;
 287                break;
 288        case AF_INET6:
 289                *(struct in6_addr *)addr.addr.a6 = inet6_sk(sk)->daddr;
 290                hash = ipv6_addr_hash(&inet6_sk(sk)->daddr);
 291                break;
 292        default:
 293                return NULL;
 294        }
 295
 296        net = dev_net(dst->dev);
 297        hash = hash_32(hash, net->ipv4.tcp_metrics_hash_log);
 298
 299        tm = __tcp_get_metrics(&addr, net, hash);
 300        reclaim = false;
 301        if (tm == TCP_METRICS_RECLAIM_PTR) {
 302                reclaim = true;
 303                tm = NULL;
 304        }
 305        if (!tm && create)
 306                tm = tcpm_new(dst, &addr, hash, reclaim);
 307        else
 308                tcpm_check_stamp(tm, dst);
 309
 310        return tm;
 311}
 312
 313/* Save metrics learned by this TCP session.  This function is called
 314 * only, when TCP finishes successfully i.e. when it enters TIME-WAIT
 315 * or goes from LAST-ACK to CLOSE.
 316 */
 317void tcp_update_metrics(struct sock *sk)
 318{
 319        const struct inet_connection_sock *icsk = inet_csk(sk);
 320        struct dst_entry *dst = __sk_dst_get(sk);
 321        struct tcp_sock *tp = tcp_sk(sk);
 322        struct tcp_metrics_block *tm;
 323        unsigned long rtt;
 324        u32 val;
 325        int m;
 326
 327        if (sysctl_tcp_nometrics_save || !dst)
 328                return;
 329
 330        if (dst->flags & DST_HOST)
 331                dst_confirm(dst);
 332
 333        rcu_read_lock();
 334        if (icsk->icsk_backoff || !tp->srtt) {
 335                /* This session failed to estimate rtt. Why?
 336                 * Probably, no packets returned in time.  Reset our
 337                 * results.
 338                 */
 339                tm = tcp_get_metrics(sk, dst, false);
 340                if (tm && !tcp_metric_locked(tm, TCP_METRIC_RTT))
 341                        tcp_metric_set(tm, TCP_METRIC_RTT, 0);
 342                goto out_unlock;
 343        } else
 344                tm = tcp_get_metrics(sk, dst, true);
 345
 346        if (!tm)
 347                goto out_unlock;
 348
 349        rtt = tcp_metric_get_jiffies(tm, TCP_METRIC_RTT);
 350        m = rtt - tp->srtt;
 351
 352        /* If newly calculated rtt larger than stored one, store new
 353         * one. Otherwise, use EWMA. Remember, rtt overestimation is
 354         * always better than underestimation.
 355         */
 356        if (!tcp_metric_locked(tm, TCP_METRIC_RTT)) {
 357                if (m <= 0)
 358                        rtt = tp->srtt;
 359                else
 360                        rtt -= (m >> 3);
 361                tcp_metric_set_msecs(tm, TCP_METRIC_RTT, rtt);
 362        }
 363
 364        if (!tcp_metric_locked(tm, TCP_METRIC_RTTVAR)) {
 365                unsigned long var;
 366
 367                if (m < 0)
 368                        m = -m;
 369
 370                /* Scale deviation to rttvar fixed point */
 371                m >>= 1;
 372                if (m < tp->mdev)
 373                        m = tp->mdev;
 374
 375                var = tcp_metric_get_jiffies(tm, TCP_METRIC_RTTVAR);
 376                if (m >= var)
 377                        var = m;
 378                else
 379                        var -= (var - m) >> 2;
 380
 381                tcp_metric_set_msecs(tm, TCP_METRIC_RTTVAR, var);
 382        }
 383
 384        if (tcp_in_initial_slowstart(tp)) {
 385                /* Slow start still did not finish. */
 386                if (!tcp_metric_locked(tm, TCP_METRIC_SSTHRESH)) {
 387                        val = tcp_metric_get(tm, TCP_METRIC_SSTHRESH);
 388                        if (val && (tp->snd_cwnd >> 1) > val)
 389                                tcp_metric_set(tm, TCP_METRIC_SSTHRESH,
 390                                               tp->snd_cwnd >> 1);
 391                }
 392                if (!tcp_metric_locked(tm, TCP_METRIC_CWND)) {
 393                        val = tcp_metric_get(tm, TCP_METRIC_CWND);
 394                        if (tp->snd_cwnd > val)
 395                                tcp_metric_set(tm, TCP_METRIC_CWND,
 396                                               tp->snd_cwnd);
 397                }
 398        } else if (tp->snd_cwnd > tp->snd_ssthresh &&
 399                   icsk->icsk_ca_state == TCP_CA_Open) {
 400                /* Cong. avoidance phase, cwnd is reliable. */
 401                if (!tcp_metric_locked(tm, TCP_METRIC_SSTHRESH))
 402                        tcp_metric_set(tm, TCP_METRIC_SSTHRESH,
 403                                       max(tp->snd_cwnd >> 1, tp->snd_ssthresh));
 404                if (!tcp_metric_locked(tm, TCP_METRIC_CWND)) {
 405                        val = tcp_metric_get(tm, TCP_METRIC_CWND);
 406                        tcp_metric_set(tm, TCP_METRIC_CWND, (val + tp->snd_cwnd) >> 1);
 407                }
 408        } else {
 409                /* Else slow start did not finish, cwnd is non-sense,
 410                 * ssthresh may be also invalid.
 411                 */
 412                if (!tcp_metric_locked(tm, TCP_METRIC_CWND)) {
 413                        val = tcp_metric_get(tm, TCP_METRIC_CWND);
 414                        tcp_metric_set(tm, TCP_METRIC_CWND,
 415                                       (val + tp->snd_ssthresh) >> 1);
 416                }
 417                if (!tcp_metric_locked(tm, TCP_METRIC_SSTHRESH)) {
 418                        val = tcp_metric_get(tm, TCP_METRIC_SSTHRESH);
 419                        if (val && tp->snd_ssthresh > val)
 420                                tcp_metric_set(tm, TCP_METRIC_SSTHRESH,
 421                                               tp->snd_ssthresh);
 422                }
 423                if (!tcp_metric_locked(tm, TCP_METRIC_REORDERING)) {
 424                        val = tcp_metric_get(tm, TCP_METRIC_REORDERING);
 425                        if (val < tp->reordering &&
 426                            tp->reordering != sysctl_tcp_reordering)
 427                                tcp_metric_set(tm, TCP_METRIC_REORDERING,
 428                                               tp->reordering);
 429                }
 430        }
 431        tm->tcpm_stamp = jiffies;
 432out_unlock:
 433        rcu_read_unlock();
 434}
 435
 436/* Initialize metrics on socket. */
 437
 438void tcp_init_metrics(struct sock *sk)
 439{
 440        struct dst_entry *dst = __sk_dst_get(sk);
 441        struct tcp_sock *tp = tcp_sk(sk);
 442        struct tcp_metrics_block *tm;
 443        u32 val;
 444
 445        if (dst == NULL)
 446                goto reset;
 447
 448        dst_confirm(dst);
 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                tcp_disable_early_retrans(tp);
 475                tp->reordering = val;
 476        }
 477
 478        val = tcp_metric_get(tm, TCP_METRIC_RTT);
 479        if (val == 0 || tp->srtt == 0) {
 480                rcu_read_unlock();
 481                goto reset;
 482        }
 483        /* Initial rtt is determined from SYN,SYN-ACK.
 484         * The segment is small and rtt may appear much
 485         * less than real one. Use per-dst memory
 486         * to make it more realistic.
 487         *
 488         * A bit of theory. RTT is time passed after "normal" sized packet
 489         * is sent until it is ACKed. In normal circumstances sending small
 490         * packets force peer to delay ACKs and calculation is correct too.
 491         * The algorithm is adaptive and, provided we follow specs, it
 492         * NEVER underestimate RTT. BUT! If peer tries to make some clever
 493         * tricks sort of "quick acks" for time long enough to decrease RTT
 494         * to low value, and then abruptly stops to do it and starts to delay
 495         * ACKs, wait for troubles.
 496         */
 497        val = msecs_to_jiffies(val);
 498        if (val > tp->srtt) {
 499                tp->srtt = val;
 500                tp->rtt_seq = tp->snd_nxt;
 501        }
 502        val = tcp_metric_get_jiffies(tm, TCP_METRIC_RTTVAR);
 503        if (val > tp->mdev) {
 504                tp->mdev = val;
 505                tp->mdev_max = tp->rttvar = max(tp->mdev, tcp_rto_min(sk));
 506        }
 507        rcu_read_unlock();
 508
 509        tcp_set_rto(sk);
 510reset:
 511        if (tp->srtt == 0) {
 512                /* RFC6298: 5.7 We've failed to get a valid RTT sample from
 513                 * 3WHS. This is most likely due to retransmission,
 514                 * including spurious one. Reset the RTO back to 3secs
 515                 * from the more aggressive 1sec to avoid more spurious
 516                 * retransmission.
 517                 */
 518                tp->mdev = tp->mdev_max = tp->rttvar = TCP_TIMEOUT_FALLBACK;
 519                inet_csk(sk)->icsk_rto = TCP_TIMEOUT_FALLBACK;
 520        }
 521        /* Cut cwnd down to 1 per RFC5681 if SYN or SYN-ACK has been
 522         * retransmitted. In light of RFC6298 more aggressive 1sec
 523         * initRTO, we only reset cwnd when more than 1 SYN/SYN-ACK
 524         * retransmission has occurred.
 525         */
 526        if (tp->total_retrans > 1)
 527                tp->snd_cwnd = 1;
 528        else
 529                tp->snd_cwnd = tcp_init_cwnd(tp, dst);
 530        tp->snd_cwnd_stamp = tcp_time_stamp;
 531}
 532
 533bool tcp_peer_is_proven(struct request_sock *req, struct dst_entry *dst, bool paws_check)
 534{
 535        struct tcp_metrics_block *tm;
 536        bool ret;
 537
 538        if (!dst)
 539                return false;
 540
 541        rcu_read_lock();
 542        tm = __tcp_get_metrics_req(req, dst);
 543        if (paws_check) {
 544                if (tm &&
 545                    (u32)get_seconds() - tm->tcpm_ts_stamp < TCP_PAWS_MSL &&
 546                    (s32)(tm->tcpm_ts - req->ts_recent) > TCP_PAWS_WINDOW)
 547                        ret = false;
 548                else
 549                        ret = true;
 550        } else {
 551                if (tm && tcp_metric_get(tm, TCP_METRIC_RTT) && tm->tcpm_ts_stamp)
 552                        ret = true;
 553                else
 554                        ret = false;
 555        }
 556        rcu_read_unlock();
 557
 558        return ret;
 559}
 560EXPORT_SYMBOL_GPL(tcp_peer_is_proven);
 561
 562void tcp_fetch_timewait_stamp(struct sock *sk, struct dst_entry *dst)
 563{
 564        struct tcp_metrics_block *tm;
 565
 566        rcu_read_lock();
 567        tm = tcp_get_metrics(sk, dst, true);
 568        if (tm) {
 569                struct tcp_sock *tp = tcp_sk(sk);
 570
 571                if ((u32)get_seconds() - tm->tcpm_ts_stamp <= TCP_PAWS_MSL) {
 572                        tp->rx_opt.ts_recent_stamp = tm->tcpm_ts_stamp;
 573                        tp->rx_opt.ts_recent = tm->tcpm_ts;
 574                }
 575        }
 576        rcu_read_unlock();
 577}
 578EXPORT_SYMBOL_GPL(tcp_fetch_timewait_stamp);
 579
 580/* VJ's idea. Save last timestamp seen from this destination and hold
 581 * it at least for normal timewait interval to use for duplicate
 582 * segment detection in subsequent connections, before they enter
 583 * synchronized state.
 584 */
 585bool tcp_remember_stamp(struct sock *sk)
 586{
 587        struct dst_entry *dst = __sk_dst_get(sk);
 588        bool ret = false;
 589
 590        if (dst) {
 591                struct tcp_metrics_block *tm;
 592
 593                rcu_read_lock();
 594                tm = tcp_get_metrics(sk, dst, true);
 595                if (tm) {
 596                        struct tcp_sock *tp = tcp_sk(sk);
 597
 598                        if ((s32)(tm->tcpm_ts - tp->rx_opt.ts_recent) <= 0 ||
 599                            ((u32)get_seconds() - tm->tcpm_ts_stamp > TCP_PAWS_MSL &&
 600                             tm->tcpm_ts_stamp <= (u32)tp->rx_opt.ts_recent_stamp)) {
 601                                tm->tcpm_ts_stamp = (u32)tp->rx_opt.ts_recent_stamp;
 602                                tm->tcpm_ts = tp->rx_opt.ts_recent;
 603                        }
 604                        ret = true;
 605                }
 606                rcu_read_unlock();
 607        }
 608        return ret;
 609}
 610
 611bool tcp_tw_remember_stamp(struct inet_timewait_sock *tw)
 612{
 613        struct tcp_metrics_block *tm;
 614        bool ret = false;
 615
 616        rcu_read_lock();
 617        tm = __tcp_get_metrics_tw(tw);
 618        if (tm) {
 619                const struct tcp_timewait_sock *tcptw;
 620                struct sock *sk = (struct sock *) tw;
 621
 622                tcptw = tcp_twsk(sk);
 623                if ((s32)(tm->tcpm_ts - tcptw->tw_ts_recent) <= 0 ||
 624                    ((u32)get_seconds() - tm->tcpm_ts_stamp > TCP_PAWS_MSL &&
 625                     tm->tcpm_ts_stamp <= (u32)tcptw->tw_ts_recent_stamp)) {
 626                        tm->tcpm_ts_stamp = (u32)tcptw->tw_ts_recent_stamp;
 627                        tm->tcpm_ts        = tcptw->tw_ts_recent;
 628                }
 629                ret = true;
 630        }
 631        rcu_read_unlock();
 632
 633        return ret;
 634}
 635
 636static DEFINE_SEQLOCK(fastopen_seqlock);
 637
 638void tcp_fastopen_cache_get(struct sock *sk, u16 *mss,
 639                            struct tcp_fastopen_cookie *cookie,
 640                            int *syn_loss, unsigned long *last_syn_loss)
 641{
 642        struct tcp_metrics_block *tm;
 643
 644        rcu_read_lock();
 645        tm = tcp_get_metrics(sk, __sk_dst_get(sk), false);
 646        if (tm) {
 647                struct tcp_fastopen_metrics *tfom = &tm->tcpm_fastopen;
 648                unsigned int seq;
 649
 650                do {
 651                        seq = read_seqbegin(&fastopen_seqlock);
 652                        if (tfom->mss)
 653                                *mss = tfom->mss;
 654                        *cookie = tfom->cookie;
 655                        *syn_loss = tfom->syn_loss;
 656                        *last_syn_loss = *syn_loss ? tfom->last_syn_loss : 0;
 657                } while (read_seqretry(&fastopen_seqlock, seq));
 658        }
 659        rcu_read_unlock();
 660}
 661
 662void tcp_fastopen_cache_set(struct sock *sk, u16 mss,
 663                            struct tcp_fastopen_cookie *cookie, bool syn_lost)
 664{
 665        struct tcp_metrics_block *tm;
 666
 667        rcu_read_lock();
 668        tm = tcp_get_metrics(sk, __sk_dst_get(sk), true);
 669        if (tm) {
 670                struct tcp_fastopen_metrics *tfom = &tm->tcpm_fastopen;
 671
 672                write_seqlock_bh(&fastopen_seqlock);
 673                tfom->mss = mss;
 674                if (cookie->len > 0)
 675                        tfom->cookie = *cookie;
 676                if (syn_lost) {
 677                        ++tfom->syn_loss;
 678                        tfom->last_syn_loss = jiffies;
 679                } else
 680                        tfom->syn_loss = 0;
 681                write_sequnlock_bh(&fastopen_seqlock);
 682        }
 683        rcu_read_unlock();
 684}
 685
 686static struct genl_family tcp_metrics_nl_family = {
 687        .id             = GENL_ID_GENERATE,
 688        .hdrsize        = 0,
 689        .name           = TCP_METRICS_GENL_NAME,
 690        .version        = TCP_METRICS_GENL_VERSION,
 691        .maxattr        = TCP_METRICS_ATTR_MAX,
 692        .netnsok        = true,
 693};
 694
 695static struct nla_policy tcp_metrics_nl_policy[TCP_METRICS_ATTR_MAX + 1] = {
 696        [TCP_METRICS_ATTR_ADDR_IPV4]    = { .type = NLA_U32, },
 697        [TCP_METRICS_ATTR_ADDR_IPV6]    = { .type = NLA_BINARY,
 698                                            .len = sizeof(struct in6_addr), },
 699        /* Following attributes are not received for GET/DEL,
 700         * we keep them for reference
 701         */
 702#if 0
 703        [TCP_METRICS_ATTR_AGE]          = { .type = NLA_MSECS, },
 704        [TCP_METRICS_ATTR_TW_TSVAL]     = { .type = NLA_U32, },
 705        [TCP_METRICS_ATTR_TW_TS_STAMP]  = { .type = NLA_S32, },
 706        [TCP_METRICS_ATTR_VALS]         = { .type = NLA_NESTED, },
 707        [TCP_METRICS_ATTR_FOPEN_MSS]    = { .type = NLA_U16, },
 708        [TCP_METRICS_ATTR_FOPEN_SYN_DROPS]      = { .type = NLA_U16, },
 709        [TCP_METRICS_ATTR_FOPEN_SYN_DROP_TS]    = { .type = NLA_MSECS, },
 710        [TCP_METRICS_ATTR_FOPEN_COOKIE] = { .type = NLA_BINARY,
 711                                            .len = TCP_FASTOPEN_COOKIE_MAX, },
 712#endif
 713};
 714
 715/* Add attributes, caller cancels its header on failure */
 716static int tcp_metrics_fill_info(struct sk_buff *msg,
 717                                 struct tcp_metrics_block *tm)
 718{
 719        struct nlattr *nest;
 720        int i;
 721
 722        switch (tm->tcpm_addr.family) {
 723        case AF_INET:
 724                if (nla_put_be32(msg, TCP_METRICS_ATTR_ADDR_IPV4,
 725                                tm->tcpm_addr.addr.a4) < 0)
 726                        goto nla_put_failure;
 727                break;
 728        case AF_INET6:
 729                if (nla_put(msg, TCP_METRICS_ATTR_ADDR_IPV6, 16,
 730                            tm->tcpm_addr.addr.a6) < 0)
 731                        goto nla_put_failure;
 732                break;
 733        default:
 734                return -EAFNOSUPPORT;
 735        }
 736
 737        if (nla_put_msecs(msg, TCP_METRICS_ATTR_AGE,
 738                          jiffies - tm->tcpm_stamp) < 0)
 739                goto nla_put_failure;
 740        if (tm->tcpm_ts_stamp) {
 741                if (nla_put_s32(msg, TCP_METRICS_ATTR_TW_TS_STAMP,
 742                                (s32) (get_seconds() - tm->tcpm_ts_stamp)) < 0)
 743                        goto nla_put_failure;
 744                if (nla_put_u32(msg, TCP_METRICS_ATTR_TW_TSVAL,
 745                                tm->tcpm_ts) < 0)
 746                        goto nla_put_failure;
 747        }
 748
 749        {
 750                int n = 0;
 751
 752                nest = nla_nest_start(msg, TCP_METRICS_ATTR_VALS);
 753                if (!nest)
 754                        goto nla_put_failure;
 755                for (i = 0; i < TCP_METRIC_MAX + 1; i++) {
 756                        if (!tm->tcpm_vals[i])
 757                                continue;
 758                        if (nla_put_u32(msg, i + 1, tm->tcpm_vals[i]) < 0)
 759                                goto nla_put_failure;
 760                        n++;
 761                }
 762                if (n)
 763                        nla_nest_end(msg, nest);
 764                else
 765                        nla_nest_cancel(msg, nest);
 766        }
 767
 768        {
 769                struct tcp_fastopen_metrics tfom_copy[1], *tfom;
 770                unsigned int seq;
 771
 772                do {
 773                        seq = read_seqbegin(&fastopen_seqlock);
 774                        tfom_copy[0] = tm->tcpm_fastopen;
 775                } while (read_seqretry(&fastopen_seqlock, seq));
 776
 777                tfom = tfom_copy;
 778                if (tfom->mss &&
 779                    nla_put_u16(msg, TCP_METRICS_ATTR_FOPEN_MSS,
 780                                tfom->mss) < 0)
 781                        goto nla_put_failure;
 782                if (tfom->syn_loss &&
 783                    (nla_put_u16(msg, TCP_METRICS_ATTR_FOPEN_SYN_DROPS,
 784                                tfom->syn_loss) < 0 ||
 785                     nla_put_msecs(msg, TCP_METRICS_ATTR_FOPEN_SYN_DROP_TS,
 786                                jiffies - tfom->last_syn_loss) < 0))
 787                        goto nla_put_failure;
 788                if (tfom->cookie.len > 0 &&
 789                    nla_put(msg, TCP_METRICS_ATTR_FOPEN_COOKIE,
 790                            tfom->cookie.len, tfom->cookie.val) < 0)
 791                        goto nla_put_failure;
 792        }
 793
 794        return 0;
 795
 796nla_put_failure:
 797        return -EMSGSIZE;
 798}
 799
 800static int tcp_metrics_dump_info(struct sk_buff *skb,
 801                                 struct netlink_callback *cb,
 802                                 struct tcp_metrics_block *tm)
 803{
 804        void *hdr;
 805
 806        hdr = genlmsg_put(skb, NETLINK_CB(cb->skb).portid, cb->nlh->nlmsg_seq,
 807                          &tcp_metrics_nl_family, NLM_F_MULTI,
 808                          TCP_METRICS_CMD_GET);
 809        if (!hdr)
 810                return -EMSGSIZE;
 811
 812        if (tcp_metrics_fill_info(skb, tm) < 0)
 813                goto nla_put_failure;
 814
 815        return genlmsg_end(skb, hdr);
 816
 817nla_put_failure:
 818        genlmsg_cancel(skb, hdr);
 819        return -EMSGSIZE;
 820}
 821
 822static int tcp_metrics_nl_dump(struct sk_buff *skb,
 823                               struct netlink_callback *cb)
 824{
 825        struct net *net = sock_net(skb->sk);
 826        unsigned int max_rows = 1U << net->ipv4.tcp_metrics_hash_log;
 827        unsigned int row, s_row = cb->args[0];
 828        int s_col = cb->args[1], col = s_col;
 829
 830        for (row = s_row; row < max_rows; row++, s_col = 0) {
 831                struct tcp_metrics_block *tm;
 832                struct tcpm_hash_bucket *hb = net->ipv4.tcp_metrics_hash + row;
 833
 834                rcu_read_lock();
 835                for (col = 0, tm = rcu_dereference(hb->chain); tm;
 836                     tm = rcu_dereference(tm->tcpm_next), col++) {
 837                        if (col < s_col)
 838                                continue;
 839                        if (tcp_metrics_dump_info(skb, cb, tm) < 0) {
 840                                rcu_read_unlock();
 841                                goto done;
 842                        }
 843                }
 844                rcu_read_unlock();
 845        }
 846
 847done:
 848        cb->args[0] = row;
 849        cb->args[1] = col;
 850        return skb->len;
 851}
 852
 853static int parse_nl_addr(struct genl_info *info, struct inetpeer_addr *addr,
 854                         unsigned int *hash, int optional)
 855{
 856        struct nlattr *a;
 857
 858        a = info->attrs[TCP_METRICS_ATTR_ADDR_IPV4];
 859        if (a) {
 860                addr->family = AF_INET;
 861                addr->addr.a4 = nla_get_be32(a);
 862                *hash = (__force unsigned int) addr->addr.a4;
 863                return 0;
 864        }
 865        a = info->attrs[TCP_METRICS_ATTR_ADDR_IPV6];
 866        if (a) {
 867                if (nla_len(a) != sizeof(struct in6_addr))
 868                        return -EINVAL;
 869                addr->family = AF_INET6;
 870                memcpy(addr->addr.a6, nla_data(a), sizeof(addr->addr.a6));
 871                *hash = ipv6_addr_hash((struct in6_addr *) addr->addr.a6);
 872                return 0;
 873        }
 874        return optional ? 1 : -EAFNOSUPPORT;
 875}
 876
 877static int tcp_metrics_nl_cmd_get(struct sk_buff *skb, struct genl_info *info)
 878{
 879        struct tcp_metrics_block *tm;
 880        struct inetpeer_addr addr;
 881        unsigned int hash;
 882        struct sk_buff *msg;
 883        struct net *net = genl_info_net(info);
 884        void *reply;
 885        int ret;
 886
 887        ret = parse_nl_addr(info, &addr, &hash, 0);
 888        if (ret < 0)
 889                return ret;
 890
 891        msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
 892        if (!msg)
 893                return -ENOMEM;
 894
 895        reply = genlmsg_put_reply(msg, info, &tcp_metrics_nl_family, 0,
 896                                  info->genlhdr->cmd);
 897        if (!reply)
 898                goto nla_put_failure;
 899
 900        hash = hash_32(hash, net->ipv4.tcp_metrics_hash_log);
 901        ret = -ESRCH;
 902        rcu_read_lock();
 903        for (tm = rcu_dereference(net->ipv4.tcp_metrics_hash[hash].chain); tm;
 904             tm = rcu_dereference(tm->tcpm_next)) {
 905                if (addr_same(&tm->tcpm_addr, &addr)) {
 906                        ret = tcp_metrics_fill_info(msg, tm);
 907                        break;
 908                }
 909        }
 910        rcu_read_unlock();
 911        if (ret < 0)
 912                goto out_free;
 913
 914        genlmsg_end(msg, reply);
 915        return genlmsg_reply(msg, info);
 916
 917nla_put_failure:
 918        ret = -EMSGSIZE;
 919
 920out_free:
 921        nlmsg_free(msg);
 922        return ret;
 923}
 924
 925#define deref_locked_genl(p)    \
 926        rcu_dereference_protected(p, lockdep_genl_is_held() && \
 927                                     lockdep_is_held(&tcp_metrics_lock))
 928
 929#define deref_genl(p)   rcu_dereference_protected(p, lockdep_genl_is_held())
 930
 931static int tcp_metrics_flush_all(struct net *net)
 932{
 933        unsigned int max_rows = 1U << net->ipv4.tcp_metrics_hash_log;
 934        struct tcpm_hash_bucket *hb = net->ipv4.tcp_metrics_hash;
 935        struct tcp_metrics_block *tm;
 936        unsigned int row;
 937
 938        for (row = 0; row < max_rows; row++, hb++) {
 939                spin_lock_bh(&tcp_metrics_lock);
 940                tm = deref_locked_genl(hb->chain);
 941                if (tm)
 942                        hb->chain = NULL;
 943                spin_unlock_bh(&tcp_metrics_lock);
 944                while (tm) {
 945                        struct tcp_metrics_block *next;
 946
 947                        next = deref_genl(tm->tcpm_next);
 948                        kfree_rcu(tm, rcu_head);
 949                        tm = next;
 950                }
 951        }
 952        return 0;
 953}
 954
 955static int tcp_metrics_nl_cmd_del(struct sk_buff *skb, struct genl_info *info)
 956{
 957        struct tcpm_hash_bucket *hb;
 958        struct tcp_metrics_block *tm;
 959        struct tcp_metrics_block __rcu **pp;
 960        struct inetpeer_addr addr;
 961        unsigned int hash;
 962        struct net *net = genl_info_net(info);
 963        int ret;
 964
 965        ret = parse_nl_addr(info, &addr, &hash, 1);
 966        if (ret < 0)
 967                return ret;
 968        if (ret > 0)
 969                return tcp_metrics_flush_all(net);
 970
 971        hash = hash_32(hash, net->ipv4.tcp_metrics_hash_log);
 972        hb = net->ipv4.tcp_metrics_hash + hash;
 973        pp = &hb->chain;
 974        spin_lock_bh(&tcp_metrics_lock);
 975        for (tm = deref_locked_genl(*pp); tm;
 976             pp = &tm->tcpm_next, tm = deref_locked_genl(*pp)) {
 977                if (addr_same(&tm->tcpm_addr, &addr)) {
 978                        *pp = tm->tcpm_next;
 979                        break;
 980                }
 981        }
 982        spin_unlock_bh(&tcp_metrics_lock);
 983        if (!tm)
 984                return -ESRCH;
 985        kfree_rcu(tm, rcu_head);
 986        return 0;
 987}
 988
 989static struct genl_ops tcp_metrics_nl_ops[] = {
 990        {
 991                .cmd = TCP_METRICS_CMD_GET,
 992                .doit = tcp_metrics_nl_cmd_get,
 993                .dumpit = tcp_metrics_nl_dump,
 994                .policy = tcp_metrics_nl_policy,
 995                .flags = GENL_ADMIN_PERM,
 996        },
 997        {
 998                .cmd = TCP_METRICS_CMD_DEL,
 999                .doit = tcp_metrics_nl_cmd_del,
1000                .policy = tcp_metrics_nl_policy,
1001                .flags = GENL_ADMIN_PERM,
1002        },
1003};
1004
1005static unsigned int tcpmhash_entries;
1006static int __init set_tcpmhash_entries(char *str)
1007{
1008        ssize_t ret;
1009
1010        if (!str)
1011                return 0;
1012
1013        ret = kstrtouint(str, 0, &tcpmhash_entries);
1014        if (ret)
1015                return 0;
1016
1017        return 1;
1018}
1019__setup("tcpmhash_entries=", set_tcpmhash_entries);
1020
1021static int __net_init tcp_net_metrics_init(struct net *net)
1022{
1023        size_t size;
1024        unsigned int slots;
1025
1026        slots = tcpmhash_entries;
1027        if (!slots) {
1028                if (totalram_pages >= 128 * 1024)
1029                        slots = 16 * 1024;
1030                else
1031                        slots = 8 * 1024;
1032        }
1033
1034        net->ipv4.tcp_metrics_hash_log = order_base_2(slots);
1035        size = sizeof(struct tcpm_hash_bucket) << net->ipv4.tcp_metrics_hash_log;
1036
1037        net->ipv4.tcp_metrics_hash = kzalloc(size, GFP_KERNEL | __GFP_NOWARN);
1038        if (!net->ipv4.tcp_metrics_hash)
1039                net->ipv4.tcp_metrics_hash = vzalloc(size);
1040
1041        if (!net->ipv4.tcp_metrics_hash)
1042                return -ENOMEM;
1043
1044        return 0;
1045}
1046
1047static void __net_exit tcp_net_metrics_exit(struct net *net)
1048{
1049        unsigned int i;
1050
1051        for (i = 0; i < (1U << net->ipv4.tcp_metrics_hash_log) ; i++) {
1052                struct tcp_metrics_block *tm, *next;
1053
1054                tm = rcu_dereference_protected(net->ipv4.tcp_metrics_hash[i].chain, 1);
1055                while (tm) {
1056                        next = rcu_dereference_protected(tm->tcpm_next, 1);
1057                        kfree(tm);
1058                        tm = next;
1059                }
1060        }
1061        if (is_vmalloc_addr(net->ipv4.tcp_metrics_hash))
1062                vfree(net->ipv4.tcp_metrics_hash);
1063        else
1064                kfree(net->ipv4.tcp_metrics_hash);
1065}
1066
1067static __net_initdata struct pernet_operations tcp_net_metrics_ops = {
1068        .init   =       tcp_net_metrics_init,
1069        .exit   =       tcp_net_metrics_exit,
1070};
1071
1072void __init tcp_metrics_init(void)
1073{
1074        int ret;
1075
1076        ret = register_pernet_subsys(&tcp_net_metrics_ops);
1077        if (ret < 0)
1078                goto cleanup;
1079        ret = genl_register_family_with_ops(&tcp_metrics_nl_family,
1080                                            tcp_metrics_nl_ops,
1081                                            ARRAY_SIZE(tcp_metrics_nl_ops));
1082        if (ret < 0)
1083                goto cleanup_subsys;
1084        return;
1085
1086cleanup_subsys:
1087        unregister_pernet_subsys(&tcp_net_metrics_ops);
1088
1089cleanup:
1090        return;
1091}
1092
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