net/xfrm/xfrm_replay.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * xfrm_replay.c - xfrm replay detection, derived from xfrm_state.c.
   4  *
   5  * Copyright (C) 2010 secunet Security Networks AG
   6  * Copyright (C) 2010 Steffen Klassert <steffen.klassert@secunet.com>
   7  */
   8
   9 #include <linux/export.h>
  10 #include <net/xfrm.h>
  11
  12 u32 xfrm_replay_seqhi(struct xfrm_state *x, __be32 net_seq)
  13 {
  14         u32 seq, seq_hi, bottom;
  15         struct xfrm_replay_state_esn *replay_esn = x->replay_esn;
  16
  17         if (!(x->props.flags & XFRM_STATE_ESN))
  18                 return 0;
  19
  20         seq = ntohl(net_seq);
  21         seq_hi = replay_esn->seq_hi;
  22         bottom = replay_esn->seq - replay_esn->replay_window + 1;
  23
  24         if (likely(replay_esn->seq >= replay_esn->replay_window - 1)) {
  25                 /* A. same subspace */
  26                 if (unlikely(seq < bottom))
  27                         seq_hi++;
  28         } else {
  29                 /* B. window spans two subspaces */
  30                 if (unlikely(seq >= bottom))
  31                         seq_hi--;
  32         }
  33
  34         return seq_hi;
  35 }
  36 EXPORT_SYMBOL(xfrm_replay_seqhi);
  37 ;
  38 static void xfrm_replay_notify(struct xfrm_state *x, int event)
  39 {
  40         struct km_event c;
  41         /* we send notify messages in case
  42          *  1. we updated on of the sequence numbers, and the seqno difference
  43          *     is at least x->replay_maxdiff, in this case we also update the
  44          *     timeout of our timer function
  45          *  2. if x->replay_maxage has elapsed since last update,
  46          *     and there were changes
  47          *
  48          *  The state structure must be locked!
  49          */
  50
  51         switch (event) {
  52         case XFRM_REPLAY_UPDATE:
  53                 if (!x->replay_maxdiff ||
  54                     ((x->replay.seq - x->preplay.seq < x->replay_maxdiff) &&
  55                     (x->replay.oseq - x->preplay.oseq < x->replay_maxdiff))) {
  56                         if (x->xflags & XFRM_TIME_DEFER)
  57                                 event = XFRM_REPLAY_TIMEOUT;
  58                         else
  59                                 return;
  60                 }
  61
  62                 break;
  63
  64         case XFRM_REPLAY_TIMEOUT:
  65                 if (memcmp(&x->replay, &x->preplay,
  66                            sizeof(struct xfrm_replay_state)) == 0) {
  67                         x->xflags |= XFRM_TIME_DEFER;
  68                         return;
  69                 }
  70
  71                 break;
  72         }
  73
  74         memcpy(&x->preplay, &x->replay, sizeof(struct xfrm_replay_state));
  75         c.event = XFRM_MSG_NEWAE;
  76         c.data.aevent = event;
  77         km_state_notify(x, &c);
  78
  79         if (x->replay_maxage &&
  80             !mod_timer(&x->rtimer, jiffies + x->replay_maxage))
  81                 x->xflags &= ~XFRM_TIME_DEFER;
  82 }
  83
  84 static int xfrm_replay_overflow(struct xfrm_state *x, struct sk_buff *skb)
  85 {
  86         int err = 0;
  87         struct net *net = xs_net(x);
  88
  89         if (x->type->flags & XFRM_TYPE_REPLAY_PROT) {
  90                 XFRM_SKB_CB(skb)->seq.output.low = ++x->replay.oseq;
  91                 XFRM_SKB_CB(skb)->seq.output.hi = 0;
  92                 if (unlikely(x->replay.oseq == 0)) {
  93                         x->replay.oseq--;
  94                         xfrm_audit_state_replay_overflow(x, skb);
  95                         err = -EOVERFLOW;
  96
  97                         return err;
  98                 }
  99                 if (xfrm_aevent_is_on(net))
 100                         x->repl->notify(x, XFRM_REPLAY_UPDATE);
 101         }
 102
 103         return err;
 104 }
 105
 106 static int xfrm_replay_check(struct xfrm_state *x,
 107                       struct sk_buff *skb, __be32 net_seq)
 108 {
 109         u32 diff;
 110         u32 seq = ntohl(net_seq);
 111
 112         if (!x->props.replay_window)
 113                 return 0;
 114
 115         if (unlikely(seq == 0))
 116                 goto err;
 117
 118         if (likely(seq > x->replay.seq))
 119                 return 0;
 120
 121         diff = x->replay.seq - seq;
 122         if (diff >= x->props.replay_window) {
 123                 x->stats.replay_window++;
 124                 goto err;
 125         }
 126
 127         if (x->replay.bitmap & (1U << diff)) {
 128                 x->stats.replay++;
 129                 goto err;
 130         }
 131         return 0;
 132
 133 err:
 134         xfrm_audit_state_replay(x, skb, net_seq);
 135         return -EINVAL;
 136 }
 137
 138 static void xfrm_replay_advance(struct xfrm_state *x, __be32 net_seq)
 139 {
 140         u32 diff;
 141         u32 seq = ntohl(net_seq);
 142
 143         if (!x->props.replay_window)
 144                 return;
 145
 146         if (seq > x->replay.seq) {
 147                 diff = seq - x->replay.seq;
 148                 if (diff < x->props.replay_window)
 149                         x->replay.bitmap = ((x->replay.bitmap) << diff) | 1;
 150                 else
 151                         x->replay.bitmap = 1;
 152                 x->replay.seq = seq;
 153         } else {
 154                 diff = x->replay.seq - seq;
 155                 x->replay.bitmap |= (1U << diff);
 156         }
 157
 158         if (xfrm_aevent_is_on(xs_net(x)))
 159                 x->repl->notify(x, XFRM_REPLAY_UPDATE);
 160 }
 161
 162 static int xfrm_replay_overflow_bmp(struct xfrm_state *x, struct sk_buff *skb)
 163 {
 164         int err = 0;
 165         struct xfrm_replay_state_esn *replay_esn = x->replay_esn;
 166         struct net *net = xs_net(x);
 167
 168         if (x->type->flags & XFRM_TYPE_REPLAY_PROT) {
 169                 XFRM_SKB_CB(skb)->seq.output.low = ++replay_esn->oseq;
 170                 XFRM_SKB_CB(skb)->seq.output.hi = 0;
 171                 if (unlikely(replay_esn->oseq == 0)) {
 172                         replay_esn->oseq--;
 173                         xfrm_audit_state_replay_overflow(x, skb);
 174                         err = -EOVERFLOW;
 175
 176                         return err;
 177                 }
 178                 if (xfrm_aevent_is_on(net))
 179                         x->repl->notify(x, XFRM_REPLAY_UPDATE);
 180         }
 181
 182         return err;
 183 }
 184
 185 static int xfrm_replay_check_bmp(struct xfrm_state *x,
 186                                  struct sk_buff *skb, __be32 net_seq)
 187 {
 188         unsigned int bitnr, nr;
 189         struct xfrm_replay_state_esn *replay_esn = x->replay_esn;
 190         u32 pos;
 191         u32 seq = ntohl(net_seq);
 192         u32 diff =  replay_esn->seq - seq;
 193
 194         if (!replay_esn->replay_window)
 195                 return 0;
 196
 197         if (unlikely(seq == 0))
 198                 goto err;
 199
 200         if (likely(seq > replay_esn->seq))
 201                 return 0;
 202
 203         if (diff >= replay_esn->replay_window) {
 204                 x->stats.replay_window++;
 205                 goto err;
 206         }
 207
 208         pos = (replay_esn->seq - 1) % replay_esn->replay_window;
 209
 210         if (pos >= diff)
 211                 bitnr = (pos - diff) % replay_esn->replay_window;
 212         else
 213                 bitnr = replay_esn->replay_window - (diff - pos);
 214
 215         nr = bitnr >> 5;
 216         bitnr = bitnr & 0x1F;
 217         if (replay_esn->bmp[nr] & (1U << bitnr))
 218                 goto err_replay;
 219
 220         return 0;
 221
 222 err_replay:
 223         x->stats.replay++;
 224 err:
 225         xfrm_audit_state_replay(x, skb, net_seq);
 226         return -EINVAL;
 227 }
 228
 229 static void xfrm_replay_advance_bmp(struct xfrm_state *x, __be32 net_seq)
 230 {
 231         unsigned int bitnr, nr, i;
 232         u32 diff;
 233         struct xfrm_replay_state_esn *replay_esn = x->replay_esn;
 234         u32 seq = ntohl(net_seq);
 235         u32 pos;
 236
 237         if (!replay_esn->replay_window)
 238                 return;
 239
 240         pos = (replay_esn->seq - 1) % replay_esn->replay_window;
 241
 242         if (seq > replay_esn->seq) {
 243                 diff = seq - replay_esn->seq;
 244
 245                 if (diff < replay_esn->replay_window) {
 246                         for (i = 1; i < diff; i++) {
 247                                 bitnr = (pos + i) % replay_esn->replay_window;
 248                                 nr = bitnr >> 5;
 249                                 bitnr = bitnr & 0x1F;
 250                                 replay_esn->bmp[nr] &=  ~(1U << bitnr);
 251                         }
 252                 } else {
 253                         nr = (replay_esn->replay_window - 1) >> 5;
 254                         for (i = 0; i <= nr; i++)
 255                                 replay_esn->bmp[i] = 0;
 256                 }
 257
 258                 bitnr = (pos + diff) % replay_esn->replay_window;
 259                 replay_esn->seq = seq;
 260         } else {
 261                 diff = replay_esn->seq - seq;
 262
 263                 if (pos >= diff)
 264                         bitnr = (pos - diff) % replay_esn->replay_window;
 265                 else
 266                         bitnr = replay_esn->replay_window - (diff - pos);
 267         }
 268
 269         nr = bitnr >> 5;
 270         bitnr = bitnr & 0x1F;
 271         replay_esn->bmp[nr] |= (1U << bitnr);
 272
 273         if (xfrm_aevent_is_on(xs_net(x)))
 274                 x->repl->notify(x, XFRM_REPLAY_UPDATE);
 275 }
 276
 277 static void xfrm_replay_notify_bmp(struct xfrm_state *x, int event)
 278 {
 279         struct km_event c;
 280         struct xfrm_replay_state_esn *replay_esn = x->replay_esn;
 281         struct xfrm_replay_state_esn *preplay_esn = x->preplay_esn;
 282
 283         /* we send notify messages in case
 284          *  1. we updated on of the sequence numbers, and the seqno difference
 285          *     is at least x->replay_maxdiff, in this case we also update the
 286          *     timeout of our timer function
 287          *  2. if x->replay_maxage has elapsed since last update,
 288          *     and there were changes
 289          *
 290          *  The state structure must be locked!
 291          */
 292
 293         switch (event) {
 294         case XFRM_REPLAY_UPDATE:
 295                 if (!x->replay_maxdiff ||
 296                     ((replay_esn->seq - preplay_esn->seq < x->replay_maxdiff) &&
 297                     (replay_esn->oseq - preplay_esn->oseq
 298                      < x->replay_maxdiff))) {
 299                         if (x->xflags & XFRM_TIME_DEFER)
 300                                 event = XFRM_REPLAY_TIMEOUT;
 301                         else
 302                                 return;
 303                 }
 304
 305                 break;
 306
 307         case XFRM_REPLAY_TIMEOUT:
 308                 if (memcmp(x->replay_esn, x->preplay_esn,
 309                            xfrm_replay_state_esn_len(replay_esn)) == 0) {
 310                         x->xflags |= XFRM_TIME_DEFER;
 311                         return;
 312                 }
 313
 314                 break;
 315         }
 316
 317         memcpy(x->preplay_esn, x->replay_esn,
 318                xfrm_replay_state_esn_len(replay_esn));
 319         c.event = XFRM_MSG_NEWAE;
 320         c.data.aevent = event;
 321         km_state_notify(x, &c);
 322
 323         if (x->replay_maxage &&
 324             !mod_timer(&x->rtimer, jiffies + x->replay_maxage))
 325                 x->xflags &= ~XFRM_TIME_DEFER;
 326 }
 327
 328 static void xfrm_replay_notify_esn(struct xfrm_state *x, int event)
 329 {
 330         u32 seq_diff, oseq_diff;
 331         struct km_event c;
 332         struct xfrm_replay_state_esn *replay_esn = x->replay_esn;
 333         struct xfrm_replay_state_esn *preplay_esn = x->preplay_esn;
 334
 335         /* we send notify messages in case
 336          *  1. we updated on of the sequence numbers, and the seqno difference
 337          *     is at least x->replay_maxdiff, in this case we also update the
 338          *     timeout of our timer function
 339          *  2. if x->replay_maxage has elapsed since last update,
 340          *     and there were changes
 341          *
 342          *  The state structure must be locked!
 343          */
 344
 345         switch (event) {
 346         case XFRM_REPLAY_UPDATE:
 347                 if (x->replay_maxdiff) {
 348                         if (replay_esn->seq_hi == preplay_esn->seq_hi)
 349                                 seq_diff = replay_esn->seq - preplay_esn->seq;
 350                         else
 351                                 seq_diff = ~preplay_esn->seq + replay_esn->seq
 352                                            + 1;
 353
 354                         if (replay_esn->oseq_hi == preplay_esn->oseq_hi)
 355                                 oseq_diff = replay_esn->oseq
 356                                             - preplay_esn->oseq;
 357                         else
 358                                 oseq_diff = ~preplay_esn->oseq
 359                                             + replay_esn->oseq + 1;
 360
 361                         if (seq_diff >= x->replay_maxdiff ||
 362                             oseq_diff >= x->replay_maxdiff)
 363                                 break;
 364                 }
 365
 366                 if (x->xflags & XFRM_TIME_DEFER)
 367                         event = XFRM_REPLAY_TIMEOUT;
 368                 else
 369                         return;
 370
 371                 break;
 372
 373         case XFRM_REPLAY_TIMEOUT:
 374                 if (memcmp(x->replay_esn, x->preplay_esn,
 375                            xfrm_replay_state_esn_len(replay_esn)) == 0) {
 376                         x->xflags |= XFRM_TIME_DEFER;
 377                         return;
 378                 }
 379
 380                 break;
 381         }
 382
 383         memcpy(x->preplay_esn, x->replay_esn,
 384                xfrm_replay_state_esn_len(replay_esn));
 385         c.event = XFRM_MSG_NEWAE;
 386         c.data.aevent = event;
 387         km_state_notify(x, &c);
 388
 389         if (x->replay_maxage &&
 390             !mod_timer(&x->rtimer, jiffies + x->replay_maxage))
 391                 x->xflags &= ~XFRM_TIME_DEFER;
 392 }
 393
 394 static int xfrm_replay_overflow_esn(struct xfrm_state *x, struct sk_buff *skb)
 395 {
 396         int err = 0;
 397         struct xfrm_replay_state_esn *replay_esn = x->replay_esn;
 398         struct net *net = xs_net(x);
 399
 400         if (x->type->flags & XFRM_TYPE_REPLAY_PROT) {
 401                 XFRM_SKB_CB(skb)->seq.output.low = ++replay_esn->oseq;
 402                 XFRM_SKB_CB(skb)->seq.output.hi = replay_esn->oseq_hi;
 403
 404                 if (unlikely(replay_esn->oseq == 0)) {
 405                         XFRM_SKB_CB(skb)->seq.output.hi = ++replay_esn->oseq_hi;
 406
 407                         if (replay_esn->oseq_hi == 0) {
 408                                 replay_esn->oseq--;
 409                                 replay_esn->oseq_hi--;
 410                                 xfrm_audit_state_replay_overflow(x, skb);
 411                                 err = -EOVERFLOW;
 412
 413                                 return err;
 414                         }
 415                 }
 416                 if (xfrm_aevent_is_on(net))
 417                         x->repl->notify(x, XFRM_REPLAY_UPDATE);
 418         }
 419
 420         return err;
 421 }
 422
 423 static int xfrm_replay_check_esn(struct xfrm_state *x,
 424                                  struct sk_buff *skb, __be32 net_seq)
 425 {
 426         unsigned int bitnr, nr;
 427         u32 diff;
 428         struct xfrm_replay_state_esn *replay_esn = x->replay_esn;
 429         u32 pos;
 430         u32 seq = ntohl(net_seq);
 431         u32 wsize = replay_esn->replay_window;
 432         u32 top = replay_esn->seq;
 433         u32 bottom = top - wsize + 1;
 434
 435         if (!wsize)
 436                 return 0;
 437
 438         if (unlikely(seq == 0 && replay_esn->seq_hi == 0 &&
 439                      (replay_esn->seq < replay_esn->replay_window - 1)))
 440                 goto err;
 441
 442         diff = top - seq;
 443
 444         if (likely(top >= wsize - 1)) {
 445                 /* A. same subspace */
 446                 if (likely(seq > top) || seq < bottom)
 447                         return 0;
 448         } else {
 449                 /* B. window spans two subspaces */
 450                 if (likely(seq > top && seq < bottom))
 451                         return 0;
 452                 if (seq >= bottom)
 453                         diff = ~seq + top + 1;
 454         }
 455
 456         if (diff >= replay_esn->replay_window) {
 457                 x->stats.replay_window++;
 458                 goto err;
 459         }
 460
 461         pos = (replay_esn->seq - 1) % replay_esn->replay_window;
 462
 463         if (pos >= diff)
 464                 bitnr = (pos - diff) % replay_esn->replay_window;
 465         else
 466                 bitnr = replay_esn->replay_window - (diff - pos);
 467
 468         nr = bitnr >> 5;
 469         bitnr = bitnr & 0x1F;
 470         if (replay_esn->bmp[nr] & (1U << bitnr))
 471                 goto err_replay;
 472
 473         return 0;
 474
 475 err_replay:
 476         x->stats.replay++;
 477 err:
 478         xfrm_audit_state_replay(x, skb, net_seq);
 479         return -EINVAL;
 480 }
 481
 482 static int xfrm_replay_recheck_esn(struct xfrm_state *x,
 483                                    struct sk_buff *skb, __be32 net_seq)
 484 {
 485         if (unlikely(XFRM_SKB_CB(skb)->seq.input.hi !=
 486                      htonl(xfrm_replay_seqhi(x, net_seq)))) {
 487                         x->stats.replay_window++;
 488                         return -EINVAL;
 489         }
 490
 491         return xfrm_replay_check_esn(x, skb, net_seq);
 492 }
 493
 494 static void xfrm_replay_advance_esn(struct xfrm_state *x, __be32 net_seq)
 495 {
 496         unsigned int bitnr, nr, i;
 497         int wrap;
 498         u32 diff, pos, seq, seq_hi;
 499         struct xfrm_replay_state_esn *replay_esn = x->replay_esn;
 500
 501         if (!replay_esn->replay_window)
 502                 return;
 503
 504         seq = ntohl(net_seq);
 505         pos = (replay_esn->seq - 1) % replay_esn->replay_window;
 506         seq_hi = xfrm_replay_seqhi(x, net_seq);
 507         wrap = seq_hi - replay_esn->seq_hi;
 508
 509         if ((!wrap && seq > replay_esn->seq) || wrap > 0) {
 510                 if (likely(!wrap))
 511                         diff = seq - replay_esn->seq;
 512                 else
 513                         diff = ~replay_esn->seq + seq + 1;
 514
 515                 if (diff < replay_esn->replay_window) {
 516                         for (i = 1; i < diff; i++) {
 517                                 bitnr = (pos + i) % replay_esn->replay_window;
 518                                 nr = bitnr >> 5;
 519                                 bitnr = bitnr & 0x1F;
 520                                 replay_esn->bmp[nr] &=  ~(1U << bitnr);
 521                         }
 522                 } else {
 523                         nr = (replay_esn->replay_window - 1) >> 5;
 524                         for (i = 0; i <= nr; i++)
 525                                 replay_esn->bmp[i] = 0;
 526                 }
 527
 528                 bitnr = (pos + diff) % replay_esn->replay_window;
 529                 replay_esn->seq = seq;
 530
 531                 if (unlikely(wrap > 0))
 532                         replay_esn->seq_hi++;
 533         } else {
 534                 diff = replay_esn->seq - seq;
 535
 536                 if (pos >= diff)
 537                         bitnr = (pos - diff) % replay_esn->replay_window;
 538                 else
 539                         bitnr = replay_esn->replay_window - (diff - pos);
 540         }
 541
 542         xfrm_dev_state_advance_esn(x);
 543
 544         nr = bitnr >> 5;
 545         bitnr = bitnr & 0x1F;
 546         replay_esn->bmp[nr] |= (1U << bitnr);
 547
 548         if (xfrm_aevent_is_on(xs_net(x)))
 549                 x->repl->notify(x, XFRM_REPLAY_UPDATE);
 550 }
 551
 552 #ifdef CONFIG_XFRM_OFFLOAD
 553 static int xfrm_replay_overflow_offload(struct xfrm_state *x, struct sk_buff *skb)
 554 {
 555         int err = 0;
 556         struct net *net = xs_net(x);
 557         struct xfrm_offload *xo = xfrm_offload(skb);
 558         __u32 oseq = x->replay.oseq;
 559
 560         if (!xo)
 561                 return xfrm_replay_overflow(x, skb);
 562
 563         if (x->type->flags & XFRM_TYPE_REPLAY_PROT) {
 564                 if (!skb_is_gso(skb)) {
 565                         XFRM_SKB_CB(skb)->seq.output.low = ++oseq;
 566                         xo->seq.low = oseq;
 567                 } else {
 568                         XFRM_SKB_CB(skb)->seq.output.low = oseq + 1;
 569                         xo->seq.low = oseq + 1;
 570                         oseq += skb_shinfo(skb)->gso_segs;
 571                 }
 572
 573                 XFRM_SKB_CB(skb)->seq.output.hi = 0;
 574                 xo->seq.hi = 0;
 575                 if (unlikely(oseq < x->replay.oseq)) {
 576                         xfrm_audit_state_replay_overflow(x, skb);
 577                         err = -EOVERFLOW;
 578
 579                         return err;
 580                 }
 581
 582                 x->replay.oseq = oseq;
 583
 584                 if (xfrm_aevent_is_on(net))
 585                         x->repl->notify(x, XFRM_REPLAY_UPDATE);
 586         }
 587
 588         return err;
 589 }
 590
 591 static int xfrm_replay_overflow_offload_bmp(struct xfrm_state *x, struct sk_buff *skb)
 592 {
 593         int err = 0;
 594         struct xfrm_offload *xo = xfrm_offload(skb);
 595         struct xfrm_replay_state_esn *replay_esn = x->replay_esn;
 596         struct net *net = xs_net(x);
 597         __u32 oseq = replay_esn->oseq;
 598
 599         if (!xo)
 600                 return xfrm_replay_overflow_bmp(x, skb);
 601
 602         if (x->type->flags & XFRM_TYPE_REPLAY_PROT) {
 603                 if (!skb_is_gso(skb)) {
 604                         XFRM_SKB_CB(skb)->seq.output.low = ++oseq;
 605                         xo->seq.low = oseq;
 606                 } else {
 607                         XFRM_SKB_CB(skb)->seq.output.low = oseq + 1;
 608                         xo->seq.low = oseq + 1;
 609                         oseq += skb_shinfo(skb)->gso_segs;
 610                 }
 611
 612                 XFRM_SKB_CB(skb)->seq.output.hi = 0;
 613                 xo->seq.hi = 0;
 614                 if (unlikely(oseq < replay_esn->oseq)) {
 615                         xfrm_audit_state_replay_overflow(x, skb);
 616                         err = -EOVERFLOW;
 617
 618                         return err;
 619                 } else {
 620                         replay_esn->oseq = oseq;
 621                 }
 622
 623                 if (xfrm_aevent_is_on(net))
 624                         x->repl->notify(x, XFRM_REPLAY_UPDATE);
 625         }
 626
 627         return err;
 628 }
 629
 630 static int xfrm_replay_overflow_offload_esn(struct xfrm_state *x, struct sk_buff *skb)
 631 {
 632         int err = 0;
 633         struct xfrm_offload *xo = xfrm_offload(skb);
 634         struct xfrm_replay_state_esn *replay_esn = x->replay_esn;
 635         struct net *net = xs_net(x);
 636         __u32 oseq = replay_esn->oseq;
 637         __u32 oseq_hi = replay_esn->oseq_hi;
 638
 639         if (!xo)
 640                 return xfrm_replay_overflow_esn(x, skb);
 641
 642         if (x->type->flags & XFRM_TYPE_REPLAY_PROT) {
 643                 if (!skb_is_gso(skb)) {
 644                         XFRM_SKB_CB(skb)->seq.output.low = ++oseq;
 645                         XFRM_SKB_CB(skb)->seq.output.hi = oseq_hi;
 646                         xo->seq.low = oseq;
 647                         xo->seq.hi = oseq_hi;
 648                 } else {
 649                         XFRM_SKB_CB(skb)->seq.output.low = oseq + 1;
 650                         XFRM_SKB_CB(skb)->seq.output.hi = oseq_hi;
 651                         xo->seq.low = oseq + 1;
 652                         xo->seq.hi = oseq_hi;
 653                         oseq += skb_shinfo(skb)->gso_segs;
 654                 }
 655
 656                 if (unlikely(oseq < replay_esn->oseq)) {
 657                         XFRM_SKB_CB(skb)->seq.output.hi = ++oseq_hi;
 658                         xo->seq.hi = oseq_hi;
 659                         replay_esn->oseq_hi = oseq_hi;
 660                         if (replay_esn->oseq_hi == 0) {
 661                                 replay_esn->oseq--;
 662                                 replay_esn->oseq_hi--;
 663                                 xfrm_audit_state_replay_overflow(x, skb);
 664                                 err = -EOVERFLOW;
 665
 666                                 return err;
 667                         }
 668                 }
 669
 670                 replay_esn->oseq = oseq;
 671
 672                 if (xfrm_aevent_is_on(net))
 673                         x->repl->notify(x, XFRM_REPLAY_UPDATE);
 674         }
 675
 676         return err;
 677 }
 678
 679 static const struct xfrm_replay xfrm_replay_legacy = {
 680         .advance        = xfrm_replay_advance,
 681         .check          = xfrm_replay_check,
 682         .recheck        = xfrm_replay_check,
 683         .notify         = xfrm_replay_notify,
 684         .overflow       = xfrm_replay_overflow_offload,
 685 };
 686
 687 static const struct xfrm_replay xfrm_replay_bmp = {
 688         .advance        = xfrm_replay_advance_bmp,
 689         .check          = xfrm_replay_check_bmp,
 690         .recheck        = xfrm_replay_check_bmp,
 691         .notify         = xfrm_replay_notify_bmp,
 692         .overflow       = xfrm_replay_overflow_offload_bmp,
 693 };
 694
 695 static const struct xfrm_replay xfrm_replay_esn = {
 696         .advance        = xfrm_replay_advance_esn,
 697         .check          = xfrm_replay_check_esn,
 698         .recheck        = xfrm_replay_recheck_esn,
 699         .notify         = xfrm_replay_notify_esn,
 700         .overflow       = xfrm_replay_overflow_offload_esn,
 701 };
 702 #else
 703 static const struct xfrm_replay xfrm_replay_legacy = {
 704         .advance        = xfrm_replay_advance,
 705         .check          = xfrm_replay_check,
 706         .recheck        = xfrm_replay_check,
 707         .notify         = xfrm_replay_notify,
 708         .overflow       = xfrm_replay_overflow,
 709 };
 710
 711 static const struct xfrm_replay xfrm_replay_bmp = {
 712         .advance        = xfrm_replay_advance_bmp,
 713         .check          = xfrm_replay_check_bmp,
 714         .recheck        = xfrm_replay_check_bmp,
 715         .notify         = xfrm_replay_notify_bmp,
 716         .overflow       = xfrm_replay_overflow_bmp,
 717 };
 718
 719 static const struct xfrm_replay xfrm_replay_esn = {
 720         .advance        = xfrm_replay_advance_esn,
 721         .check          = xfrm_replay_check_esn,
 722         .recheck        = xfrm_replay_recheck_esn,
 723         .notify         = xfrm_replay_notify_esn,
 724         .overflow       = xfrm_replay_overflow_esn,
 725 };
 726 #endif
 727
 728 int xfrm_init_replay(struct xfrm_state *x)
 729 {
 730         struct xfrm_replay_state_esn *replay_esn = x->replay_esn;
 731
 732         if (replay_esn) {
 733                 if (replay_esn->replay_window >
 734                     replay_esn->bmp_len * sizeof(__u32) * 8)
 735                         return -EINVAL;
 736
 737                 if (x->props.flags & XFRM_STATE_ESN) {
 738                         if (replay_esn->replay_window == 0)
 739                                 return -EINVAL;
 740                         x->repl = &xfrm_replay_esn;
 741                 } else {
 742                         x->repl = &xfrm_replay_bmp;
 743                 }
 744         } else {
 745                 x->repl = &xfrm_replay_legacy;
 746         }
 747
 748         return 0;
 749 }
 750 EXPORT_SYMBOL(xfrm_init_replay);