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>

1 files changed, 34 insertions, 64 deletions

diff --git a/net/xfrm/xfrm_replay.c b/net/xfrm/xfrm_replay.c
index b11ea692bd7d..6ca357406ea8 100644
--- 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);
 }