xfrm: Simplify the replay check and advance functions

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>

diff --git a/net/xfrm/xfrm_replay.c b/net/xfrm/xfrm_replay.c
index b11ea69..6ca3574 100644 (file)
--- a/net/xfrm/xfrm_replay.c
+++ b/net/xfrm/xfrm_replay.c
@@ -203,8 +203,6 @@ static int xfrm_replay_check_bmp(struct xfrm_state *x,
        if (!replay_esn->replay_window)
                return 0;
 
-       pos = (replay_esn->seq - 1) % replay_esn->replay_window;
-
        if (unlikely(seq == 0))
                goto err;
 
@@ -216,19 +214,18 @@ static int xfrm_replay_check_bmp(struct xfrm_state *x,
                goto err;
        }
 
-       if (pos >= diff) {
+       pos = (replay_esn->seq - 1) % replay_esn->replay_window;
+
+       if (pos >= diff)
                bitnr = (pos - diff) % replay_esn->replay_window;
-               nr = bitnr >> 5;
-               bitnr = bitnr & 0x1F;
-               if (replay_esn->bmp[nr] & (1U << bitnr))
-                       goto err_replay;
-       } else {
+       else
                bitnr = replay_esn->replay_window - (diff - pos);
-               nr = bitnr >> 5;
-               bitnr = bitnr & 0x1F;
-               if (replay_esn->bmp[nr] & (1U << bitnr))
-                       goto err_replay;
-       }
+
+       nr = bitnr >> 5;
+       bitnr = bitnr & 0x1F;
+       if (replay_esn->bmp[nr] & (1U << bitnr))
+               goto err_replay;
+
        return 0;
 
 err_replay:
@@ -259,39 +256,27 @@ static void xfrm_replay_advance_bmp(struct xfrm_state *x, __be32 net_seq)
                                bitnr = bitnr & 0x1F;
                                replay_esn->bmp[nr] &=  ~(1U << bitnr);
                        }
-
-                       bitnr = (pos + diff) % replay_esn->replay_window;
-                       nr = bitnr >> 5;
-                       bitnr = bitnr & 0x1F;
-                       replay_esn->bmp[nr] |= (1U << bitnr);
                } else {
                        nr = (replay_esn->replay_window - 1) >> 5;
                        for (i = 0; i <= nr; i++)
                                replay_esn->bmp[i] = 0;
-
-                       bitnr = (pos + diff) % replay_esn->replay_window;
-                       nr = bitnr >> 5;
-                       bitnr = bitnr & 0x1F;
-                       replay_esn->bmp[nr] |= (1U << bitnr);
                }
 
+               bitnr = (pos + diff) % replay_esn->replay_window;
                replay_esn->seq = seq;
        } else {
                diff = replay_esn->seq - seq;
 
-               if (pos >= diff) {
+               if (pos >= diff)
                        bitnr = (pos - diff) % replay_esn->replay_window;
-                       nr = bitnr >> 5;
-                       bitnr = bitnr & 0x1F;
-                       replay_esn->bmp[nr] |= (1U << bitnr);
-               } else {
+               else
                        bitnr = replay_esn->replay_window - (diff - pos);
-                       nr = bitnr >> 5;
-                       bitnr = bitnr & 0x1F;
-                       replay_esn->bmp[nr] |= (1U << bitnr);
-               }
        }
 
+       nr = bitnr >> 5;
+       bitnr = bitnr & 0x1F;
+       replay_esn->bmp[nr] |= (1U << bitnr);
+
        if (xfrm_aevent_is_on(xs_net(x)))
                xfrm_replay_notify(x, XFRM_REPLAY_UPDATE);
 }
@@ -390,8 +375,6 @@ static int xfrm_replay_check_esn(struct xfrm_state *x,
        if (!wsize)
                return 0;
 
-       pos = (replay_esn->seq - 1) % replay_esn->replay_window;
-
        if (unlikely(seq == 0 && replay_esn->seq_hi == 0 &&
                     (replay_esn->seq < replay_esn->replay_window - 1)))
                goto err;
@@ -415,19 +398,18 @@ static int xfrm_replay_check_esn(struct xfrm_state *x,
                goto err;
        }
 
-       if (pos >= diff) {
+       pos = (replay_esn->seq - 1) % replay_esn->replay_window;
+
+       if (pos >= diff)
                bitnr = (pos - diff) % replay_esn->replay_window;
-               nr = bitnr >> 5;
-               bitnr = bitnr & 0x1F;
-               if (replay_esn->bmp[nr] & (1U << bitnr))
-                       goto err_replay;
-       } else {
+       else
                bitnr = replay_esn->replay_window - (diff - pos);
-               nr = bitnr >> 5;
-               bitnr = bitnr & 0x1F;
-               if (replay_esn->bmp[nr] & (1U << bitnr))
-                       goto err_replay;
-       }
+
+       nr = bitnr >> 5;
+       bitnr = bitnr & 0x1F;
+       if (replay_esn->bmp[nr] & (1U << bitnr))
+               goto err_replay;
+
        return 0;
 
 err_replay:
@@ -465,22 +447,13 @@ static void xfrm_replay_advance_esn(struct xfrm_state *x, __be32 net_seq)
                                bitnr = bitnr & 0x1F;
                                replay_esn->bmp[nr] &=  ~(1U << bitnr);
                        }
-
-                       bitnr = (pos + diff) % replay_esn->replay_window;
-                       nr = bitnr >> 5;
-                       bitnr = bitnr & 0x1F;
-                       replay_esn->bmp[nr] |= (1U << bitnr);
                } else {
                        nr = (replay_esn->replay_window - 1) >> 5;
                        for (i = 0; i <= nr; i++)
                                replay_esn->bmp[i] = 0;
-
-                       bitnr = (pos + diff) % replay_esn->replay_window;
-                       nr = bitnr >> 5;
-                       bitnr = bitnr & 0x1F;
-                       replay_esn->bmp[nr] |= (1U << bitnr);
                }
 
+               bitnr = (pos + diff) % replay_esn->replay_window;
                replay_esn->seq = seq;
 
                if (unlikely(wrap > 0))
@@ -488,19 +461,16 @@ static void xfrm_replay_advance_esn(struct xfrm_state *x, __be32 net_seq)
        } else {
                diff = replay_esn->seq - seq;
 
-               if (pos >= diff) {
+               if (pos >= diff)
                        bitnr = (pos - diff) % replay_esn->replay_window;
-                       nr = bitnr >> 5;
-                       bitnr = bitnr & 0x1F;
-                       replay_esn->bmp[nr] |= (1U << bitnr);
-               } else {
+               else
                        bitnr = replay_esn->replay_window - (diff - pos);
-                       nr = bitnr >> 5;
-                       bitnr = bitnr & 0x1F;
-                       replay_esn->bmp[nr] |= (1U << bitnr);
-               }
        }
 
+       nr = bitnr >> 5;
+       bitnr = bitnr & 0x1F;
+       replay_esn->bmp[nr] |= (1U << bitnr);
+
        if (xfrm_aevent_is_on(xs_net(x)))
                xfrm_replay_notify(x, XFRM_REPLAY_UPDATE);
 }