[PATCH ipsec-next v2 0/5] xfrm: remove xfrm replay indirections

[PATCH ipsec-next v2 0/5] xfrm: remove xfrm replay indirections

[Florian Westphal]

This is v2 of an older patchset that got stuck in backlog hell. Changes:

 - drop bogus "get rid of duplicated notification code" patch. As noted
   by Sabrina it does change behavior.
 - fix a compiler warning in patch 2.

ipsec.c selftest passes.

The xfrm replay logic is implemented via indirect calls.

xfrm_state struct holds a pointer to a
'struct xfrm_replay', which is one of several replay protection
backends.

XFRM then invokes the backend via state->repl->callback().
Due to retpoline all indirect calls have become a lot more
expensive.  Fortunately, there are no 'replay modules', all are available
for direct calls.

This series removes the 'struct xfrm_replay' and adds replay
functions that can be called instead of the redirection.

Example:
  -  err = x->repl->overflow(x, skb);
  +  err = xfrm_replay_overflow(x, skb);

Instead of a pointer to a struct with function pointers, xfrm_state
now holds an enum that tells the replay core what kind of replay
test is to be done.

Florian Westphal (5):
  xfrm: replay: avoid xfrm replay notify indirection
  xfrm: replay: remove advance indirection
  xfrm: replay: remove recheck indirection
  xfrm: replay: avoid replay indirection
  xfrm: replay: remove last replay indirection

 include/net/xfrm.h     |  29 ++++---
 net/xfrm/xfrm_input.c  |   6 +-
 net/xfrm/xfrm_output.c |   2 +-
 net/xfrm/xfrm_replay.c | 171 +++++++++++++++++++++++++----------------
 net/xfrm/xfrm_state.c  |   2 +-
 5 files changed, 123 insertions(+), 87 deletions(-)

-- 
2.31.1

[PATCH ipsec-next v2 1/5] xfrm: replay: avoid xfrm replay notify indirection

[Florian Westphal]

replay protection is implemented using a callback structure and then
called via

   x->repl->notify(), x->repl->recheck(), and so on.

all the differect functions are always built-in, so this could be direct
calls instead.

This first patch prepares for removal of the x->repl structure.
Add an enum with the three available replay modes to the xfrm_state
structure and then replace all x->repl->notify() calls by the new
xfrm_replay_notify() helper.

The helper checks the enum internally to adapt behaviour as needed.

Signed-off-by: Florian Westphal <fw@strlen.de>
---
 include/net/xfrm.h     | 11 ++++++++++-
 net/xfrm/xfrm_replay.c | 45 ++++++++++++++++++++++++++----------------
 net/xfrm/xfrm_state.c  |  2 +-
 3 files changed, 39 insertions(+), 19 deletions(-)

diff --git a/include/net/xfrm.h b/include/net/xfrm.h
index 3a01570410ab..9a79e41defa7 100644
--- a/include/net/xfrm.h
+++ b/include/net/xfrm.h
@@ -145,6 +145,12 @@ enum {
 	XFRM_MODE_FLAG_TUNNEL = 1,
 };
 
+enum xfrm_replay_mode {
+	XFRM_REPLAY_MODE_LEGACY,
+	XFRM_REPLAY_MODE_BMP,
+	XFRM_REPLAY_MODE_ESN,
+};
+
 /* Full description of state of transformer. */
 struct xfrm_state {
 	possible_net_t		xs_net;
@@ -218,6 +224,8 @@ struct xfrm_state {
 	/* The functions for replay detection. */
 	const struct xfrm_replay *repl;
 
+	/* replay detection mode */
+	enum xfrm_replay_mode    repl_mode;
 	/* internal flag that only holds state for delayed aevent at the
 	 * moment
 	*/
@@ -305,7 +313,6 @@ struct xfrm_replay {
 	int	(*recheck)(struct xfrm_state *x,
 			   struct sk_buff *skb,
 			   __be32 net_seq);
-	void	(*notify)(struct xfrm_state *x, int event);
 	int	(*overflow)(struct xfrm_state *x, struct sk_buff *skb);
 };
 
@@ -1715,6 +1722,8 @@ static inline int xfrm_policy_id2dir(u32 index)
 }
 
 #ifdef CONFIG_XFRM
+void xfrm_replay_notify(struct xfrm_state *x, int event);
+
 static inline int xfrm_aevent_is_on(struct net *net)
 {
 	struct sock *nlsk;
diff --git a/net/xfrm/xfrm_replay.c b/net/xfrm/xfrm_replay.c
index c6a4338a0d08..5feeb65f00b3 100644
--- a/net/xfrm/xfrm_replay.c
+++ b/net/xfrm/xfrm_replay.c
@@ -34,8 +34,11 @@ u32 xfrm_replay_seqhi(struct xfrm_state *x, __be32 net_seq)
 	return seq_hi;
 }
 EXPORT_SYMBOL(xfrm_replay_seqhi);
-;
-static void xfrm_replay_notify(struct xfrm_state *x, int event)
+
+static void xfrm_replay_notify_bmp(struct xfrm_state *x, int event);
+static void xfrm_replay_notify_esn(struct xfrm_state *x, int event);
+
+void xfrm_replay_notify(struct xfrm_state *x, int event)
 {
 	struct km_event c;
 	/* we send notify messages in case
@@ -48,6 +51,17 @@ static void xfrm_replay_notify(struct xfrm_state *x, int event)
 	 *  The state structure must be locked!
 	 */
 
+	switch (x->repl_mode) {
+	case XFRM_REPLAY_MODE_LEGACY:
+		break;
+	case XFRM_REPLAY_MODE_BMP:
+		xfrm_replay_notify_bmp(x, event);
+		return;
+	case XFRM_REPLAY_MODE_ESN:
+		xfrm_replay_notify_esn(x, event);
+		return;
+	}
+
 	switch (event) {
 	case XFRM_REPLAY_UPDATE:
 		if (!x->replay_maxdiff ||
@@ -98,7 +112,7 @@ static int xfrm_replay_overflow(struct xfrm_state *x, struct sk_buff *skb)
 			return err;
 		}
 		if (xfrm_aevent_is_on(net))
-			x->repl->notify(x, XFRM_REPLAY_UPDATE);
+			xfrm_replay_notify(x, XFRM_REPLAY_UPDATE);
 	}
 
 	return err;
@@ -157,7 +171,7 @@ static void xfrm_replay_advance(struct xfrm_state *x, __be32 net_seq)
 	}
 
 	if (xfrm_aevent_is_on(xs_net(x)))
-		x->repl->notify(x, XFRM_REPLAY_UPDATE);
+		xfrm_replay_notify(x, XFRM_REPLAY_UPDATE);
 }
 
 static int xfrm_replay_overflow_bmp(struct xfrm_state *x, struct sk_buff *skb)
@@ -178,7 +192,7 @@ static int xfrm_replay_overflow_bmp(struct xfrm_state *x, struct sk_buff *skb)
 			return err;
 		}
 		if (xfrm_aevent_is_on(net))
-			x->repl->notify(x, XFRM_REPLAY_UPDATE);
+			xfrm_replay_notify(x, XFRM_REPLAY_UPDATE);
 	}
 
 	return err;
@@ -273,7 +287,7 @@ static void xfrm_replay_advance_bmp(struct xfrm_state *x, __be32 net_seq)
 	replay_esn->bmp[nr] |= (1U << bitnr);
 
 	if (xfrm_aevent_is_on(xs_net(x)))
-		x->repl->notify(x, XFRM_REPLAY_UPDATE);
+		xfrm_replay_notify(x, XFRM_REPLAY_UPDATE);
 }
 
 static void xfrm_replay_notify_bmp(struct xfrm_state *x, int event)
@@ -416,7 +430,7 @@ static int xfrm_replay_overflow_esn(struct xfrm_state *x, struct sk_buff *skb)
 			}
 		}
 		if (xfrm_aevent_is_on(net))
-			x->repl->notify(x, XFRM_REPLAY_UPDATE);
+			xfrm_replay_notify(x, XFRM_REPLAY_UPDATE);
 	}
 
 	return err;
@@ -548,7 +562,7 @@ static void xfrm_replay_advance_esn(struct xfrm_state *x, __be32 net_seq)
 	replay_esn->bmp[nr] |= (1U << bitnr);
 
 	if (xfrm_aevent_is_on(xs_net(x)))
-		x->repl->notify(x, XFRM_REPLAY_UPDATE);
+		xfrm_replay_notify(x, XFRM_REPLAY_UPDATE);
 }
 
 #ifdef CONFIG_XFRM_OFFLOAD
@@ -585,7 +599,7 @@ static int xfrm_replay_overflow_offload(struct xfrm_state *x, struct sk_buff *sk
 		x->replay.oseq = oseq;
 
 		if (xfrm_aevent_is_on(net))
-			x->repl->notify(x, XFRM_REPLAY_UPDATE);
+			xfrm_replay_notify(x, XFRM_REPLAY_UPDATE);
 	}
 
 	return err;
@@ -625,7 +639,7 @@ static int xfrm_replay_overflow_offload_bmp(struct xfrm_state *x, struct sk_buff
 		}
 
 		if (xfrm_aevent_is_on(net))
-			x->repl->notify(x, XFRM_REPLAY_UPDATE);
+			xfrm_replay_notify(x, XFRM_REPLAY_UPDATE);
 	}
 
 	return err;
@@ -674,7 +688,7 @@ static int xfrm_replay_overflow_offload_esn(struct xfrm_state *x, struct sk_buff
 		replay_esn->oseq = oseq;
 
 		if (xfrm_aevent_is_on(net))
-			x->repl->notify(x, XFRM_REPLAY_UPDATE);
+			xfrm_replay_notify(x, XFRM_REPLAY_UPDATE);
 	}
 
 	return err;
@@ -684,7 +698,6 @@ static const struct xfrm_replay xfrm_replay_legacy = {
 	.advance	= xfrm_replay_advance,
 	.check		= xfrm_replay_check,
 	.recheck	= xfrm_replay_check,
-	.notify		= xfrm_replay_notify,
 	.overflow	= xfrm_replay_overflow_offload,
 };
 
@@ -692,7 +705,6 @@ static const struct xfrm_replay xfrm_replay_bmp = {
 	.advance	= xfrm_replay_advance_bmp,
 	.check		= xfrm_replay_check_bmp,
 	.recheck	= xfrm_replay_check_bmp,
-	.notify		= xfrm_replay_notify_bmp,
 	.overflow	= xfrm_replay_overflow_offload_bmp,
 };
 
@@ -700,7 +712,6 @@ static const struct xfrm_replay xfrm_replay_esn = {
 	.advance	= xfrm_replay_advance_esn,
 	.check		= xfrm_replay_check_esn,
 	.recheck	= xfrm_replay_recheck_esn,
-	.notify		= xfrm_replay_notify_esn,
 	.overflow	= xfrm_replay_overflow_offload_esn,
 };
 #else
@@ -708,7 +719,6 @@ static const struct xfrm_replay xfrm_replay_legacy = {
 	.advance	= xfrm_replay_advance,
 	.check		= xfrm_replay_check,
 	.recheck	= xfrm_replay_check,
-	.notify		= xfrm_replay_notify,
 	.overflow	= xfrm_replay_overflow,
 };
 
@@ -716,7 +726,6 @@ static const struct xfrm_replay xfrm_replay_bmp = {
 	.advance	= xfrm_replay_advance_bmp,
 	.check		= xfrm_replay_check_bmp,
 	.recheck	= xfrm_replay_check_bmp,
-	.notify		= xfrm_replay_notify_bmp,
 	.overflow	= xfrm_replay_overflow_bmp,
 };
 
@@ -724,7 +733,6 @@ static const struct xfrm_replay xfrm_replay_esn = {
 	.advance	= xfrm_replay_advance_esn,
 	.check		= xfrm_replay_check_esn,
 	.recheck	= xfrm_replay_recheck_esn,
-	.notify		= xfrm_replay_notify_esn,
 	.overflow	= xfrm_replay_overflow_esn,
 };
 #endif
@@ -742,11 +750,14 @@ int xfrm_init_replay(struct xfrm_state *x)
 			if (replay_esn->replay_window == 0)
 				return -EINVAL;
 			x->repl = &xfrm_replay_esn;
+			x->repl_mode = XFRM_REPLAY_MODE_ESN;
 		} else {
 			x->repl = &xfrm_replay_bmp;
+			x->repl_mode = XFRM_REPLAY_MODE_BMP;
 		}
 	} else {
 		x->repl = &xfrm_replay_legacy;
+		x->repl_mode = XFRM_REPLAY_MODE_LEGACY;
 	}
 
 	return 0;
diff --git a/net/xfrm/xfrm_state.c b/net/xfrm/xfrm_state.c
index 8f6058e56f7f..c2ce1e6f4760 100644
--- a/net/xfrm/xfrm_state.c
+++ b/net/xfrm/xfrm_state.c
@@ -2177,7 +2177,7 @@ static void xfrm_replay_timer_handler(struct timer_list *t)
 
 	if (x->km.state == XFRM_STATE_VALID) {
 		if (xfrm_aevent_is_on(xs_net(x)))
-			x->repl->notify(x, XFRM_REPLAY_TIMEOUT);
+			xfrm_replay_notify(x, XFRM_REPLAY_TIMEOUT);
 		else
 			x->xflags |= XFRM_TIME_DEFER;
 	}
-- 
2.31.1

[PATCH ipsec-next v2 2/5] xfrm: replay: remove advance indirection

[Florian Westphal]

Similar to other patches: add a new helper to avoid
an indirection.

v2: fix 'net/xfrm/xfrm_replay.c:519:13: warning: 'seq' may be used
uninitialized in this function' warning.

Signed-off-by: Florian Westphal <fw@strlen.de>
---
 include/net/xfrm.h     |  2 +-
 net/xfrm/xfrm_input.c  |  2 +-
 net/xfrm/xfrm_replay.c | 24 +++++++++++++++---------
 3 files changed, 17 insertions(+), 11 deletions(-)

diff --git a/include/net/xfrm.h b/include/net/xfrm.h
index 9a79e41defa7..a7f997b13198 100644
--- a/include/net/xfrm.h
+++ b/include/net/xfrm.h
@@ -306,7 +306,6 @@ struct km_event {
 };
 
 struct xfrm_replay {
-	void	(*advance)(struct xfrm_state *x, __be32 net_seq);
 	int	(*check)(struct xfrm_state *x,
 			 struct sk_buff *skb,
 			 __be32 net_seq);
@@ -1722,6 +1721,7 @@ static inline int xfrm_policy_id2dir(u32 index)
 }
 
 #ifdef CONFIG_XFRM
+void xfrm_replay_advance(struct xfrm_state *x, __be32 net_seq);
 void xfrm_replay_notify(struct xfrm_state *x, int event);
 
 static inline int xfrm_aevent_is_on(struct net *net)
diff --git a/net/xfrm/xfrm_input.c b/net/xfrm/xfrm_input.c
index 1158cd0311d7..c8971e4b33ab 100644
--- a/net/xfrm/xfrm_input.c
+++ b/net/xfrm/xfrm_input.c
@@ -665,7 +665,7 @@ int xfrm_input(struct sk_buff *skb, int nexthdr, __be32 spi, int encap_type)
 			goto drop_unlock;
 		}
 
-		x->repl->advance(x, seq);
+		xfrm_replay_advance(x, seq);
 
 		x->curlft.bytes += skb->len;
 		x->curlft.packets++;
diff --git a/net/xfrm/xfrm_replay.c b/net/xfrm/xfrm_replay.c
index 5feeb65f00b3..9565b0f7d380 100644
--- a/net/xfrm/xfrm_replay.c
+++ b/net/xfrm/xfrm_replay.c
@@ -150,14 +150,26 @@ static int xfrm_replay_check(struct xfrm_state *x,
 	return -EINVAL;
 }
 
-static void xfrm_replay_advance(struct xfrm_state *x, __be32 net_seq)
+static void xfrm_replay_advance_bmp(struct xfrm_state *x, __be32 net_seq);
+static void xfrm_replay_advance_esn(struct xfrm_state *x, __be32 net_seq);
+
+void xfrm_replay_advance(struct xfrm_state *x, __be32 net_seq)
 {
-	u32 diff;
-	u32 seq = ntohl(net_seq);
+	u32 diff, seq;
+
+	switch (x->repl_mode) {
+	case XFRM_REPLAY_MODE_LEGACY:
+		break;
+	case XFRM_REPLAY_MODE_BMP:
+		return xfrm_replay_advance_bmp(x, net_seq);
+	case XFRM_REPLAY_MODE_ESN:
+		return xfrm_replay_advance_esn(x, net_seq);
+	}
 
 	if (!x->props.replay_window)
 		return;
 
+	seq = ntohl(net_seq);
 	if (seq > x->replay.seq) {
 		diff = seq - x->replay.seq;
 		if (diff < x->props.replay_window)
@@ -695,42 +707,36 @@ static int xfrm_replay_overflow_offload_esn(struct xfrm_state *x, struct sk_buff
 }
 
 static const struct xfrm_replay xfrm_replay_legacy = {
-	.advance	= xfrm_replay_advance,
 	.check		= xfrm_replay_check,
 	.recheck	= xfrm_replay_check,
 	.overflow	= xfrm_replay_overflow_offload,
 };
 
 static const struct xfrm_replay xfrm_replay_bmp = {
-	.advance	= xfrm_replay_advance_bmp,
 	.check		= xfrm_replay_check_bmp,
 	.recheck	= xfrm_replay_check_bmp,
 	.overflow	= xfrm_replay_overflow_offload_bmp,
 };
 
 static const struct xfrm_replay xfrm_replay_esn = {
-	.advance	= xfrm_replay_advance_esn,
 	.check		= xfrm_replay_check_esn,
 	.recheck	= xfrm_replay_recheck_esn,
 	.overflow	= xfrm_replay_overflow_offload_esn,
 };
 #else
 static const struct xfrm_replay xfrm_replay_legacy = {
-	.advance	= xfrm_replay_advance,
 	.check		= xfrm_replay_check,
 	.recheck	= xfrm_replay_check,
 	.overflow	= xfrm_replay_overflow,
 };
 
 static const struct xfrm_replay xfrm_replay_bmp = {
-	.advance	= xfrm_replay_advance_bmp,
 	.check		= xfrm_replay_check_bmp,
 	.recheck	= xfrm_replay_check_bmp,
 	.overflow	= xfrm_replay_overflow_bmp,
 };
 
 static const struct xfrm_replay xfrm_replay_esn = {
-	.advance	= xfrm_replay_advance_esn,
 	.check		= xfrm_replay_check_esn,
 	.recheck	= xfrm_replay_recheck_esn,
 	.overflow	= xfrm_replay_overflow_esn,
-- 
2.31.1

[PATCH ipsec-next v2 3/5] xfrm: replay: remove recheck indirection

[Florian Westphal]

Adds new xfrm_replay_recheck() helper and calls it from
xfrm input path instead of the indirection.

Signed-off-by: Florian Westphal <fw@strlen.de>
---
 include/net/xfrm.h     |  4 +---
 net/xfrm/xfrm_input.c  |  2 +-
 net/xfrm/xfrm_replay.c | 22 ++++++++++++++++------
 3 files changed, 18 insertions(+), 10 deletions(-)

diff --git a/include/net/xfrm.h b/include/net/xfrm.h
index a7f997b13198..3a219b34cb8c 100644
--- a/include/net/xfrm.h
+++ b/include/net/xfrm.h
@@ -309,9 +309,6 @@ struct xfrm_replay {
 	int	(*check)(struct xfrm_state *x,
 			 struct sk_buff *skb,
 			 __be32 net_seq);
-	int	(*recheck)(struct xfrm_state *x,
-			   struct sk_buff *skb,
-			   __be32 net_seq);
 	int	(*overflow)(struct xfrm_state *x, struct sk_buff *skb);
 };
 
@@ -1723,6 +1720,7 @@ static inline int xfrm_policy_id2dir(u32 index)
 #ifdef CONFIG_XFRM
 void xfrm_replay_advance(struct xfrm_state *x, __be32 net_seq);
 void xfrm_replay_notify(struct xfrm_state *x, int event);
+int xfrm_replay_recheck(struct xfrm_state *x, struct sk_buff *skb, __be32 net_seq);
 
 static inline int xfrm_aevent_is_on(struct net *net)
 {
diff --git a/net/xfrm/xfrm_input.c b/net/xfrm/xfrm_input.c
index c8971e4b33ab..8046ef1a6680 100644
--- a/net/xfrm/xfrm_input.c
+++ b/net/xfrm/xfrm_input.c
@@ -660,7 +660,7 @@ int xfrm_input(struct sk_buff *skb, int nexthdr, __be32 spi, int encap_type)
 		/* only the first xfrm gets the encap type */
 		encap_type = 0;
 
-		if (x->repl->recheck(x, skb, seq)) {
+		if (xfrm_replay_recheck(x, skb, seq)) {
 			XFRM_INC_STATS(net, LINUX_MIB_XFRMINSTATESEQERROR);
 			goto drop_unlock;
 		}
diff --git a/net/xfrm/xfrm_replay.c b/net/xfrm/xfrm_replay.c
index 9565b0f7d380..59391dc80fa3 100644
--- a/net/xfrm/xfrm_replay.c
+++ b/net/xfrm/xfrm_replay.c
@@ -519,6 +519,22 @@ static int xfrm_replay_recheck_esn(struct xfrm_state *x,
 	return xfrm_replay_check_esn(x, skb, net_seq);
 }
 
+int xfrm_replay_recheck(struct xfrm_state *x,
+			struct sk_buff *skb, __be32 net_seq)
+{
+	switch (x->repl_mode) {
+	case XFRM_REPLAY_MODE_LEGACY:
+		break;
+	case XFRM_REPLAY_MODE_BMP:
+		/* no special recheck treatment */
+		return xfrm_replay_check_bmp(x, skb, net_seq);
+	case XFRM_REPLAY_MODE_ESN:
+		return xfrm_replay_recheck_esn(x, skb, net_seq);
+	}
+
+	return xfrm_replay_check(x, skb, net_seq);
+}
+
 static void xfrm_replay_advance_esn(struct xfrm_state *x, __be32 net_seq)
 {
 	unsigned int bitnr, nr, i;
@@ -708,37 +724,31 @@ static int xfrm_replay_overflow_offload_esn(struct xfrm_state *x, struct sk_buff
 
 static const struct xfrm_replay xfrm_replay_legacy = {
 	.check		= xfrm_replay_check,
-	.recheck	= xfrm_replay_check,
 	.overflow	= xfrm_replay_overflow_offload,
 };
 
 static const struct xfrm_replay xfrm_replay_bmp = {
 	.check		= xfrm_replay_check_bmp,
-	.recheck	= xfrm_replay_check_bmp,
 	.overflow	= xfrm_replay_overflow_offload_bmp,
 };
 
 static const struct xfrm_replay xfrm_replay_esn = {
 	.check		= xfrm_replay_check_esn,
-	.recheck	= xfrm_replay_recheck_esn,
 	.overflow	= xfrm_replay_overflow_offload_esn,
 };
 #else
 static const struct xfrm_replay xfrm_replay_legacy = {
 	.check		= xfrm_replay_check,
-	.recheck	= xfrm_replay_check,
 	.overflow	= xfrm_replay_overflow,
 };
 
 static const struct xfrm_replay xfrm_replay_bmp = {
 	.check		= xfrm_replay_check_bmp,
-	.recheck	= xfrm_replay_check_bmp,
 	.overflow	= xfrm_replay_overflow_bmp,
 };
 
 static const struct xfrm_replay xfrm_replay_esn = {
 	.check		= xfrm_replay_check_esn,
-	.recheck	= xfrm_replay_recheck_esn,
 	.overflow	= xfrm_replay_overflow_esn,
 };
 #endif
-- 
2.31.1

[PATCH ipsec-next v2 4/5] xfrm: replay: avoid replay indirection

[Florian Westphal]

Add and use xfrm_replay_check helper instead of indirection.

Signed-off-by: Florian Westphal <fw@strlen.de>
---
 include/net/xfrm.h     |  4 +---
 net/xfrm/xfrm_input.c  |  2 +-
 net/xfrm/xfrm_replay.c | 27 ++++++++++++++++++---------
 3 files changed, 20 insertions(+), 13 deletions(-)

diff --git a/include/net/xfrm.h b/include/net/xfrm.h
index 3a219b34cb8c..0206d80ec291 100644
--- a/include/net/xfrm.h
+++ b/include/net/xfrm.h
@@ -306,9 +306,6 @@ struct km_event {
 };
 
 struct xfrm_replay {
-	int	(*check)(struct xfrm_state *x,
-			 struct sk_buff *skb,
-			 __be32 net_seq);
 	int	(*overflow)(struct xfrm_state *x, struct sk_buff *skb);
 };
 
@@ -1719,6 +1716,7 @@ static inline int xfrm_policy_id2dir(u32 index)
 
 #ifdef CONFIG_XFRM
 void xfrm_replay_advance(struct xfrm_state *x, __be32 net_seq);
+int xfrm_replay_check(struct xfrm_state *x, struct sk_buff *skb, __be32 net_seq);
 void xfrm_replay_notify(struct xfrm_state *x, int event);
 int xfrm_replay_recheck(struct xfrm_state *x, struct sk_buff *skb, __be32 net_seq);
 
diff --git a/net/xfrm/xfrm_input.c b/net/xfrm/xfrm_input.c
index 8046ef1a6680..3df0861d4390 100644
--- a/net/xfrm/xfrm_input.c
+++ b/net/xfrm/xfrm_input.c
@@ -612,7 +612,7 @@ int xfrm_input(struct sk_buff *skb, int nexthdr, __be32 spi, int encap_type)
 			goto drop_unlock;
 		}
 
-		if (x->repl->check(x, skb, seq)) {
+		if (xfrm_replay_check(x, skb, seq)) {
 			XFRM_INC_STATS(net, LINUX_MIB_XFRMINSTATESEQERROR);
 			goto drop_unlock;
 		}
diff --git a/net/xfrm/xfrm_replay.c b/net/xfrm/xfrm_replay.c
index 59391dc80fa3..e8703aa8d06a 100644
--- a/net/xfrm/xfrm_replay.c
+++ b/net/xfrm/xfrm_replay.c
@@ -118,8 +118,8 @@ static int xfrm_replay_overflow(struct xfrm_state *x, struct sk_buff *skb)
 	return err;
 }
 
-static int xfrm_replay_check(struct xfrm_state *x,
-		      struct sk_buff *skb, __be32 net_seq)
+static int xfrm_replay_check_legacy(struct xfrm_state *x,
+				    struct sk_buff *skb, __be32 net_seq)
 {
 	u32 diff;
 	u32 seq = ntohl(net_seq);
@@ -507,6 +507,21 @@ static int xfrm_replay_check_esn(struct xfrm_state *x,
 	return -EINVAL;
 }
 
+int xfrm_replay_check(struct xfrm_state *x,
+		      struct sk_buff *skb, __be32 net_seq)
+{
+	switch (x->repl_mode) {
+	case XFRM_REPLAY_MODE_LEGACY:
+		break;
+	case XFRM_REPLAY_MODE_BMP:
+		return xfrm_replay_check_bmp(x, skb, net_seq);
+	case XFRM_REPLAY_MODE_ESN:
+		return xfrm_replay_check_esn(x, skb, net_seq);
+	}
+
+	return xfrm_replay_check_legacy(x, skb, net_seq);
+}
+
 static int xfrm_replay_recheck_esn(struct xfrm_state *x,
 				   struct sk_buff *skb, __be32 net_seq)
 {
@@ -532,7 +547,7 @@ int xfrm_replay_recheck(struct xfrm_state *x,
 		return xfrm_replay_recheck_esn(x, skb, net_seq);
 	}
 
-	return xfrm_replay_check(x, skb, net_seq);
+	return xfrm_replay_check_legacy(x, skb, net_seq);
 }
 
 static void xfrm_replay_advance_esn(struct xfrm_state *x, __be32 net_seq)
@@ -723,32 +738,26 @@ static int xfrm_replay_overflow_offload_esn(struct xfrm_state *x, struct sk_buff
 }
 
 static const struct xfrm_replay xfrm_replay_legacy = {
-	.check		= xfrm_replay_check,
 	.overflow	= xfrm_replay_overflow_offload,
 };
 
 static const struct xfrm_replay xfrm_replay_bmp = {
-	.check		= xfrm_replay_check_bmp,
 	.overflow	= xfrm_replay_overflow_offload_bmp,
 };
 
 static const struct xfrm_replay xfrm_replay_esn = {
-	.check		= xfrm_replay_check_esn,
 	.overflow	= xfrm_replay_overflow_offload_esn,
 };
 #else
 static const struct xfrm_replay xfrm_replay_legacy = {
-	.check		= xfrm_replay_check,
 	.overflow	= xfrm_replay_overflow,
 };
 
 static const struct xfrm_replay xfrm_replay_bmp = {
-	.check		= xfrm_replay_check_bmp,
 	.overflow	= xfrm_replay_overflow_bmp,
 };
 
 static const struct xfrm_replay xfrm_replay_esn = {
-	.check		= xfrm_replay_check_esn,
 	.overflow	= xfrm_replay_overflow_esn,
 };
 #endif
-- 
2.31.1

[PATCH ipsec-next v2 5/5] xfrm: replay: remove last replay indirection

[Florian Westphal]

This replaces the overflow indirection with the new xfrm_replay_overflow
helper.  After this, the 'repl' pointer in xfrm_state is no longer
needed and can be removed as well.

xfrm_replay_overflow() is added in two incarnations, one is used
when the kernel is compiled with xfrm hardware offload support enabled,
the other when its disabled.

Signed-off-by: Florian Westphal <fw@strlen.de>
---
 include/net/xfrm.h     |  8 +------
 net/xfrm/xfrm_output.c |  2 +-
 net/xfrm/xfrm_replay.c | 51 +++++++++++++++++++++---------------------
 3 files changed, 28 insertions(+), 33 deletions(-)

diff --git a/include/net/xfrm.h b/include/net/xfrm.h
index 0206d80ec291..d2a0559c255f 100644
--- a/include/net/xfrm.h
+++ b/include/net/xfrm.h
@@ -221,9 +221,6 @@ struct xfrm_state {
 	struct xfrm_replay_state preplay;
 	struct xfrm_replay_state_esn *preplay_esn;
 
-	/* The functions for replay detection. */
-	const struct xfrm_replay *repl;
-
 	/* replay detection mode */
 	enum xfrm_replay_mode    repl_mode;
 	/* internal flag that only holds state for delayed aevent at the
@@ -305,10 +302,6 @@ struct km_event {
 	struct net *net;
 };
 
-struct xfrm_replay {
-	int	(*overflow)(struct xfrm_state *x, struct sk_buff *skb);
-};
-
 struct xfrm_if_cb {
 	struct xfrm_if	*(*decode_session)(struct sk_buff *skb,
 					   unsigned short family);
@@ -1718,6 +1711,7 @@ static inline int xfrm_policy_id2dir(u32 index)
 void xfrm_replay_advance(struct xfrm_state *x, __be32 net_seq);
 int xfrm_replay_check(struct xfrm_state *x, struct sk_buff *skb, __be32 net_seq);
 void xfrm_replay_notify(struct xfrm_state *x, int event);
+int xfrm_replay_overflow(struct xfrm_state *x, struct sk_buff *skb);
 int xfrm_replay_recheck(struct xfrm_state *x, struct sk_buff *skb, __be32 net_seq);
 
 static inline int xfrm_aevent_is_on(struct net *net)
diff --git a/net/xfrm/xfrm_output.c b/net/xfrm/xfrm_output.c
index 0b2975ef0668..527da58464f3 100644
--- a/net/xfrm/xfrm_output.c
+++ b/net/xfrm/xfrm_output.c
@@ -525,7 +525,7 @@ static int xfrm_output_one(struct sk_buff *skb, int err)
 			goto error;
 		}
 
-		err = x->repl->overflow(x, skb);
+		err = xfrm_replay_overflow(x, skb);
 		if (err) {
 			XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTSTATESEQERROR);
 			goto error;
diff --git a/net/xfrm/xfrm_replay.c b/net/xfrm/xfrm_replay.c
index e8703aa8d06a..9277d81b344c 100644
--- a/net/xfrm/xfrm_replay.c
+++ b/net/xfrm/xfrm_replay.c
@@ -95,7 +95,7 @@ void xfrm_replay_notify(struct xfrm_state *x, int event)
 		x->xflags &= ~XFRM_TIME_DEFER;
 }
 
-static int xfrm_replay_overflow(struct xfrm_state *x, struct sk_buff *skb)
+static int __xfrm_replay_overflow(struct xfrm_state *x, struct sk_buff *skb)
 {
 	int err = 0;
 	struct net *net = xs_net(x);
@@ -617,7 +617,7 @@ static int xfrm_replay_overflow_offload(struct xfrm_state *x, struct sk_buff *sk
 	__u32 oseq = x->replay.oseq;
 
 	if (!xo)
-		return xfrm_replay_overflow(x, skb);
+		return __xfrm_replay_overflow(x, skb);
 
 	if (x->type->flags & XFRM_TYPE_REPLAY_PROT) {
 		if (!skb_is_gso(skb)) {
@@ -737,29 +737,33 @@ static int xfrm_replay_overflow_offload_esn(struct xfrm_state *x, struct sk_buff
 	return err;
 }
 
-static const struct xfrm_replay xfrm_replay_legacy = {
-	.overflow	= xfrm_replay_overflow_offload,
-};
-
-static const struct xfrm_replay xfrm_replay_bmp = {
-	.overflow	= xfrm_replay_overflow_offload_bmp,
-};
+int xfrm_replay_overflow(struct xfrm_state *x, struct sk_buff *skb)
+{
+	switch (x->repl_mode) {
+	case XFRM_REPLAY_MODE_LEGACY:
+		break;
+	case XFRM_REPLAY_MODE_BMP:
+		return xfrm_replay_overflow_offload_bmp(x, skb);
+	case XFRM_REPLAY_MODE_ESN:
+		return xfrm_replay_overflow_offload_esn(x, skb);
+	}
 
-static const struct xfrm_replay xfrm_replay_esn = {
-	.overflow	= xfrm_replay_overflow_offload_esn,
-};
+	return xfrm_replay_overflow_offload(x, skb);
+}
 #else
-static const struct xfrm_replay xfrm_replay_legacy = {
-	.overflow	= xfrm_replay_overflow,
-};
-
-static const struct xfrm_replay xfrm_replay_bmp = {
-	.overflow	= xfrm_replay_overflow_bmp,
-};
+int xfrm_replay_overflow(struct xfrm_state *x, struct sk_buff *skb)
+{
+	switch (x->repl_mode) {
+	case XFRM_REPLAY_MODE_LEGACY:
+		break;
+	case XFRM_REPLAY_MODE_BMP:
+		return xfrm_replay_overflow_bmp(x, skb);
+	case XFRM_REPLAY_MODE_ESN:
+		return xfrm_replay_overflow_esn(x, skb);
+	}
 
-static const struct xfrm_replay xfrm_replay_esn = {
-	.overflow	= xfrm_replay_overflow_esn,
-};
+	return __xfrm_replay_overflow(x, skb);
+}
 #endif
 
 int xfrm_init_replay(struct xfrm_state *x)
@@ -774,14 +778,11 @@ int xfrm_init_replay(struct xfrm_state *x)
 		if (x->props.flags & XFRM_STATE_ESN) {
 			if (replay_esn->replay_window == 0)
 				return -EINVAL;
-			x->repl = &xfrm_replay_esn;
 			x->repl_mode = XFRM_REPLAY_MODE_ESN;
 		} else {
-			x->repl = &xfrm_replay_bmp;
 			x->repl_mode = XFRM_REPLAY_MODE_BMP;
 		}
 	} else {
-		x->repl = &xfrm_replay_legacy;
 		x->repl_mode = XFRM_REPLAY_MODE_LEGACY;
 	}
 
-- 
2.31.1

Re: [PATCH ipsec-next v2 0/5] xfrm: remove xfrm replay indirections

[Steffen Klassert]

On Fri, Jun 18, 2021 at 03:51:55PM +0200, Florian Westphal wrote:
> This is v2 of an older patchset that got stuck in backlog hell. Changes:
> 
>  - drop bogus "get rid of duplicated notification code" patch. As noted
>    by Sabrina it does change behavior.
>  - fix a compiler warning in patch 2.
> 
> ipsec.c selftest passes.
> 
> The xfrm replay logic is implemented via indirect calls.
> 
> xfrm_state struct holds a pointer to a
> 'struct xfrm_replay', which is one of several replay protection
> backends.
> 
> XFRM then invokes the backend via state->repl->callback().
> Due to retpoline all indirect calls have become a lot more
> expensive.  Fortunately, there are no 'replay modules', all are available
> for direct calls.
> 
> This series removes the 'struct xfrm_replay' and adds replay
> functions that can be called instead of the redirection.
> 
> Example:
>   -  err = x->repl->overflow(x, skb);
>   +  err = xfrm_replay_overflow(x, skb);
> 
> Instead of a pointer to a struct with function pointers, xfrm_state
> now holds an enum that tells the replay core what kind of replay
> test is to be done.
> 
> Florian Westphal (5):
>   xfrm: replay: avoid xfrm replay notify indirection
>   xfrm: replay: remove advance indirection
>   xfrm: replay: remove recheck indirection
>   xfrm: replay: avoid replay indirection
>   xfrm: replay: remove last replay indirection

All applied, thanks a lot Florian!