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/net/xfrm/xfrm_replay.c

http://github.com/mirrors/linux
C | 750 lines | 581 code | 131 blank | 38 comment | 126 complexity | f3a1f588dd63259e498e96f50544de82 MD5 | raw file
  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
 12u32 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}
 36EXPORT_SYMBOL(xfrm_replay_seqhi);
 37;
 38static 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
 84static 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
106static 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
133err:
134	xfrm_audit_state_replay(x, skb, net_seq);
135	return -EINVAL;
136}
137
138static 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
162static 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
185static 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
222err_replay:
223	x->stats.replay++;
224err:
225	xfrm_audit_state_replay(x, skb, net_seq);
226	return -EINVAL;
227}
228
229static 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
277static 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
328static 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
394static 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
423static 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
475err_replay:
476	x->stats.replay++;
477err:
478	xfrm_audit_state_replay(x, skb, net_seq);
479	return -EINVAL;
480}
481
482static 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
494static 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
553static 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
591static 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
630static 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
679static 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
687static 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
695static 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
703static 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
711static 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
719static 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
728int 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}
750EXPORT_SYMBOL(xfrm_init_replay);