![Steffen Klassert](/assets/img/avatar_default.png)
The replay check and replay advance functions had some code duplications. This patch removes the duplications. Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com> Signed-off-by: David S. Miller <davem@davemloft.net>
521 lines
12 KiB
C
521 lines
12 KiB
C
/*
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* xfrm_replay.c - xfrm replay detection, derived from xfrm_state.c.
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*
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* Copyright (C) 2010 secunet Security Networks AG
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* Copyright (C) 2010 Steffen Klassert <steffen.klassert@secunet.com>
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms and conditions of the GNU General Public License,
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* version 2, as published by the Free Software Foundation.
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*
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* This program is distributed in the hope it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
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* more details.
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*
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* You should have received a copy of the GNU General Public License along with
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* this program; if not, write to the Free Software Foundation, Inc.,
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* 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
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*/
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#include <net/xfrm.h>
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u32 xfrm_replay_seqhi(struct xfrm_state *x, __be32 net_seq)
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{
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u32 seq, seq_hi, bottom;
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struct xfrm_replay_state_esn *replay_esn = x->replay_esn;
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if (!(x->props.flags & XFRM_STATE_ESN))
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return 0;
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seq = ntohl(net_seq);
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seq_hi = replay_esn->seq_hi;
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bottom = replay_esn->seq - replay_esn->replay_window + 1;
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if (likely(replay_esn->seq >= replay_esn->replay_window - 1)) {
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/* A. same subspace */
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if (unlikely(seq < bottom))
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seq_hi++;
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} else {
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/* B. window spans two subspaces */
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if (unlikely(seq >= bottom))
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seq_hi--;
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}
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return seq_hi;
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}
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static void xfrm_replay_notify(struct xfrm_state *x, int event)
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{
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struct km_event c;
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/* we send notify messages in case
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* 1. we updated on of the sequence numbers, and the seqno difference
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* is at least x->replay_maxdiff, in this case we also update the
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* timeout of our timer function
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* 2. if x->replay_maxage has elapsed since last update,
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* and there were changes
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*
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* The state structure must be locked!
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*/
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switch (event) {
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case XFRM_REPLAY_UPDATE:
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if (x->replay_maxdiff &&
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(x->replay.seq - x->preplay.seq < x->replay_maxdiff) &&
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(x->replay.oseq - x->preplay.oseq < x->replay_maxdiff)) {
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if (x->xflags & XFRM_TIME_DEFER)
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event = XFRM_REPLAY_TIMEOUT;
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else
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return;
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}
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break;
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case XFRM_REPLAY_TIMEOUT:
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if (memcmp(&x->replay, &x->preplay,
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sizeof(struct xfrm_replay_state)) == 0) {
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x->xflags |= XFRM_TIME_DEFER;
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return;
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}
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break;
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}
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memcpy(&x->preplay, &x->replay, sizeof(struct xfrm_replay_state));
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c.event = XFRM_MSG_NEWAE;
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c.data.aevent = event;
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km_state_notify(x, &c);
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if (x->replay_maxage &&
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!mod_timer(&x->rtimer, jiffies + x->replay_maxage))
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x->xflags &= ~XFRM_TIME_DEFER;
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}
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static int xfrm_replay_overflow(struct xfrm_state *x, struct sk_buff *skb)
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{
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int err = 0;
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struct net *net = xs_net(x);
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if (x->type->flags & XFRM_TYPE_REPLAY_PROT) {
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XFRM_SKB_CB(skb)->seq.output.low = ++x->replay.oseq;
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if (unlikely(x->replay.oseq == 0)) {
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x->replay.oseq--;
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xfrm_audit_state_replay_overflow(x, skb);
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err = -EOVERFLOW;
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return err;
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}
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if (xfrm_aevent_is_on(net))
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x->repl->notify(x, XFRM_REPLAY_UPDATE);
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}
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return err;
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}
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static int xfrm_replay_check(struct xfrm_state *x,
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struct sk_buff *skb, __be32 net_seq)
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{
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u32 diff;
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u32 seq = ntohl(net_seq);
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if (!x->props.replay_window)
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return 0;
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if (unlikely(seq == 0))
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goto err;
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if (likely(seq > x->replay.seq))
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return 0;
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diff = x->replay.seq - seq;
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if (diff >= min_t(unsigned int, x->props.replay_window,
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sizeof(x->replay.bitmap) * 8)) {
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x->stats.replay_window++;
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goto err;
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}
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if (x->replay.bitmap & (1U << diff)) {
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x->stats.replay++;
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goto err;
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}
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return 0;
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err:
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xfrm_audit_state_replay(x, skb, net_seq);
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return -EINVAL;
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}
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static void xfrm_replay_advance(struct xfrm_state *x, __be32 net_seq)
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{
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u32 diff;
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u32 seq = ntohl(net_seq);
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if (!x->props.replay_window)
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return;
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if (seq > x->replay.seq) {
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diff = seq - x->replay.seq;
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if (diff < x->props.replay_window)
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x->replay.bitmap = ((x->replay.bitmap) << diff) | 1;
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else
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x->replay.bitmap = 1;
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x->replay.seq = seq;
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} else {
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diff = x->replay.seq - seq;
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x->replay.bitmap |= (1U << diff);
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}
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if (xfrm_aevent_is_on(xs_net(x)))
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xfrm_replay_notify(x, XFRM_REPLAY_UPDATE);
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}
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static int xfrm_replay_overflow_bmp(struct xfrm_state *x, struct sk_buff *skb)
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{
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int err = 0;
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struct xfrm_replay_state_esn *replay_esn = x->replay_esn;
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struct net *net = xs_net(x);
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if (x->type->flags & XFRM_TYPE_REPLAY_PROT) {
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XFRM_SKB_CB(skb)->seq.output.low = ++replay_esn->oseq;
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if (unlikely(replay_esn->oseq == 0)) {
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replay_esn->oseq--;
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xfrm_audit_state_replay_overflow(x, skb);
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err = -EOVERFLOW;
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return err;
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}
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if (xfrm_aevent_is_on(net))
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x->repl->notify(x, XFRM_REPLAY_UPDATE);
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}
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return err;
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}
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static int xfrm_replay_check_bmp(struct xfrm_state *x,
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struct sk_buff *skb, __be32 net_seq)
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{
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unsigned int bitnr, nr;
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struct xfrm_replay_state_esn *replay_esn = x->replay_esn;
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u32 pos;
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u32 seq = ntohl(net_seq);
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u32 diff = replay_esn->seq - seq;
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if (!replay_esn->replay_window)
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return 0;
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if (unlikely(seq == 0))
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goto err;
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if (likely(seq > replay_esn->seq))
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return 0;
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if (diff >= replay_esn->replay_window) {
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x->stats.replay_window++;
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goto err;
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}
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pos = (replay_esn->seq - 1) % replay_esn->replay_window;
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if (pos >= diff)
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bitnr = (pos - diff) % replay_esn->replay_window;
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else
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bitnr = replay_esn->replay_window - (diff - pos);
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nr = bitnr >> 5;
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bitnr = bitnr & 0x1F;
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if (replay_esn->bmp[nr] & (1U << bitnr))
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goto err_replay;
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return 0;
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err_replay:
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x->stats.replay++;
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err:
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xfrm_audit_state_replay(x, skb, net_seq);
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return -EINVAL;
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}
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static void xfrm_replay_advance_bmp(struct xfrm_state *x, __be32 net_seq)
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{
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unsigned int bitnr, nr, i;
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u32 diff;
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struct xfrm_replay_state_esn *replay_esn = x->replay_esn;
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u32 seq = ntohl(net_seq);
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u32 pos = (replay_esn->seq - 1) % replay_esn->replay_window;
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if (!replay_esn->replay_window)
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return;
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if (seq > replay_esn->seq) {
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diff = seq - replay_esn->seq;
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if (diff < replay_esn->replay_window) {
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for (i = 1; i < diff; i++) {
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bitnr = (pos + i) % replay_esn->replay_window;
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nr = bitnr >> 5;
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bitnr = bitnr & 0x1F;
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replay_esn->bmp[nr] &= ~(1U << bitnr);
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}
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} else {
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nr = (replay_esn->replay_window - 1) >> 5;
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for (i = 0; i <= nr; i++)
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replay_esn->bmp[i] = 0;
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}
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bitnr = (pos + diff) % replay_esn->replay_window;
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replay_esn->seq = seq;
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} else {
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diff = replay_esn->seq - seq;
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if (pos >= diff)
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bitnr = (pos - diff) % replay_esn->replay_window;
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else
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bitnr = replay_esn->replay_window - (diff - pos);
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}
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nr = bitnr >> 5;
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bitnr = bitnr & 0x1F;
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replay_esn->bmp[nr] |= (1U << bitnr);
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if (xfrm_aevent_is_on(xs_net(x)))
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xfrm_replay_notify(x, XFRM_REPLAY_UPDATE);
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}
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static void xfrm_replay_notify_bmp(struct xfrm_state *x, int event)
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{
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struct km_event c;
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struct xfrm_replay_state_esn *replay_esn = x->replay_esn;
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struct xfrm_replay_state_esn *preplay_esn = x->preplay_esn;
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/* we send notify messages in case
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* 1. we updated on of the sequence numbers, and the seqno difference
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* is at least x->replay_maxdiff, in this case we also update the
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* timeout of our timer function
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* 2. if x->replay_maxage has elapsed since last update,
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* and there were changes
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*
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* The state structure must be locked!
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*/
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switch (event) {
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case XFRM_REPLAY_UPDATE:
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if (x->replay_maxdiff &&
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(replay_esn->seq - preplay_esn->seq < x->replay_maxdiff) &&
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(replay_esn->oseq - preplay_esn->oseq < x->replay_maxdiff)) {
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if (x->xflags & XFRM_TIME_DEFER)
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event = XFRM_REPLAY_TIMEOUT;
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else
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return;
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}
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break;
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case XFRM_REPLAY_TIMEOUT:
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if (memcmp(x->replay_esn, x->preplay_esn,
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xfrm_replay_state_esn_len(replay_esn)) == 0) {
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x->xflags |= XFRM_TIME_DEFER;
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return;
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}
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break;
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}
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memcpy(x->preplay_esn, x->replay_esn,
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xfrm_replay_state_esn_len(replay_esn));
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c.event = XFRM_MSG_NEWAE;
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c.data.aevent = event;
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km_state_notify(x, &c);
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if (x->replay_maxage &&
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!mod_timer(&x->rtimer, jiffies + x->replay_maxage))
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x->xflags &= ~XFRM_TIME_DEFER;
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}
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static int xfrm_replay_overflow_esn(struct xfrm_state *x, struct sk_buff *skb)
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{
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int err = 0;
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struct xfrm_replay_state_esn *replay_esn = x->replay_esn;
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struct net *net = xs_net(x);
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if (x->type->flags & XFRM_TYPE_REPLAY_PROT) {
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XFRM_SKB_CB(skb)->seq.output.low = ++replay_esn->oseq;
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XFRM_SKB_CB(skb)->seq.output.hi = replay_esn->oseq_hi;
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if (unlikely(replay_esn->oseq == 0)) {
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XFRM_SKB_CB(skb)->seq.output.hi = ++replay_esn->oseq_hi;
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if (replay_esn->oseq_hi == 0) {
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replay_esn->oseq--;
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replay_esn->oseq_hi--;
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xfrm_audit_state_replay_overflow(x, skb);
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err = -EOVERFLOW;
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return err;
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}
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}
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if (xfrm_aevent_is_on(net))
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x->repl->notify(x, XFRM_REPLAY_UPDATE);
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}
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return err;
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}
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static int xfrm_replay_check_esn(struct xfrm_state *x,
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struct sk_buff *skb, __be32 net_seq)
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{
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unsigned int bitnr, nr;
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u32 diff;
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struct xfrm_replay_state_esn *replay_esn = x->replay_esn;
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u32 pos;
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u32 seq = ntohl(net_seq);
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u32 wsize = replay_esn->replay_window;
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u32 top = replay_esn->seq;
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u32 bottom = top - wsize + 1;
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if (!wsize)
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return 0;
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if (unlikely(seq == 0 && replay_esn->seq_hi == 0 &&
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(replay_esn->seq < replay_esn->replay_window - 1)))
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goto err;
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diff = top - seq;
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if (likely(top >= wsize - 1)) {
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/* A. same subspace */
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if (likely(seq > top) || seq < bottom)
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return 0;
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} else {
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/* B. window spans two subspaces */
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if (likely(seq > top && seq < bottom))
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return 0;
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if (seq >= bottom)
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diff = ~seq + top + 1;
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}
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if (diff >= replay_esn->replay_window) {
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x->stats.replay_window++;
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goto err;
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}
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pos = (replay_esn->seq - 1) % replay_esn->replay_window;
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if (pos >= diff)
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bitnr = (pos - diff) % replay_esn->replay_window;
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else
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bitnr = replay_esn->replay_window - (diff - pos);
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nr = bitnr >> 5;
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bitnr = bitnr & 0x1F;
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if (replay_esn->bmp[nr] & (1U << bitnr))
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goto err_replay;
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return 0;
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err_replay:
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x->stats.replay++;
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err:
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xfrm_audit_state_replay(x, skb, net_seq);
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return -EINVAL;
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}
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static void xfrm_replay_advance_esn(struct xfrm_state *x, __be32 net_seq)
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{
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unsigned int bitnr, nr, i;
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int wrap;
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u32 diff, pos, seq, seq_hi;
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struct xfrm_replay_state_esn *replay_esn = x->replay_esn;
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if (!replay_esn->replay_window)
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return;
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seq = ntohl(net_seq);
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pos = (replay_esn->seq - 1) % replay_esn->replay_window;
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seq_hi = xfrm_replay_seqhi(x, net_seq);
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wrap = seq_hi - replay_esn->seq_hi;
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if ((!wrap && seq > replay_esn->seq) || wrap > 0) {
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if (likely(!wrap))
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diff = seq - replay_esn->seq;
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else
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diff = ~replay_esn->seq + seq + 1;
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if (diff < replay_esn->replay_window) {
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for (i = 1; i < diff; i++) {
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bitnr = (pos + i) % replay_esn->replay_window;
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nr = bitnr >> 5;
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bitnr = bitnr & 0x1F;
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replay_esn->bmp[nr] &= ~(1U << bitnr);
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}
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} else {
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nr = (replay_esn->replay_window - 1) >> 5;
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for (i = 0; i <= nr; i++)
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replay_esn->bmp[i] = 0;
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}
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bitnr = (pos + diff) % replay_esn->replay_window;
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replay_esn->seq = seq;
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if (unlikely(wrap > 0))
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replay_esn->seq_hi++;
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} else {
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diff = replay_esn->seq - seq;
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if (pos >= diff)
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bitnr = (pos - diff) % replay_esn->replay_window;
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else
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bitnr = replay_esn->replay_window - (diff - pos);
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}
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nr = bitnr >> 5;
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bitnr = bitnr & 0x1F;
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replay_esn->bmp[nr] |= (1U << bitnr);
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if (xfrm_aevent_is_on(xs_net(x)))
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xfrm_replay_notify(x, XFRM_REPLAY_UPDATE);
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}
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static struct xfrm_replay xfrm_replay_legacy = {
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.advance = xfrm_replay_advance,
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.check = xfrm_replay_check,
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.notify = xfrm_replay_notify,
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.overflow = xfrm_replay_overflow,
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};
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static struct xfrm_replay xfrm_replay_bmp = {
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.advance = xfrm_replay_advance_bmp,
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.check = xfrm_replay_check_bmp,
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.notify = xfrm_replay_notify_bmp,
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.overflow = xfrm_replay_overflow_bmp,
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};
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static struct xfrm_replay xfrm_replay_esn = {
|
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.advance = xfrm_replay_advance_esn,
|
|
.check = xfrm_replay_check_esn,
|
|
.notify = xfrm_replay_notify_bmp,
|
|
.overflow = xfrm_replay_overflow_esn,
|
|
};
|
|
|
|
int xfrm_init_replay(struct xfrm_state *x)
|
|
{
|
|
struct xfrm_replay_state_esn *replay_esn = x->replay_esn;
|
|
|
|
if (replay_esn) {
|
|
if (replay_esn->replay_window >
|
|
replay_esn->bmp_len * sizeof(__u32) * 8)
|
|
return -EINVAL;
|
|
|
|
if ((x->props.flags & XFRM_STATE_ESN) && replay_esn->replay_window == 0)
|
|
return -EINVAL;
|
|
|
|
if ((x->props.flags & XFRM_STATE_ESN) && x->replay_esn)
|
|
x->repl = &xfrm_replay_esn;
|
|
else
|
|
x->repl = &xfrm_replay_bmp;
|
|
} else
|
|
x->repl = &xfrm_replay_legacy;
|
|
|
|
return 0;
|
|
}
|
|
EXPORT_SYMBOL(xfrm_init_replay);
|