[IPSEC]: Move output replay code into xfrm_output

The replay counter is one of only two remaining things in the output code
that requires a lock on the xfrm state (the other being the crypto).  This
patch moves it into the generic xfrm_output so we can remove the lock from
the transforms themselves.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>

6 files changed, 32 insertions, 9 deletions

diff --git a/include/net/xfrm.h b/include/net/xfrm.h
index bb9193434eb3..a267725f9753 100644
--- a/include/net/xfrm.h
+++ b/include/net/xfrm.h
@@ -2,7 +2,6 @@
 #define _NET_XFRM_H
 
 #include <linux/compiler.h>
-#include <linux/in.h>
 #include <linux/xfrm.h>
 #include <linux/spinlock.h>
 #include <linux/list.h>
@@ -16,6 +15,7 @@
 
 #include <net/sock.h>
 #include <net/dst.h>
+#include <net/ip.h>
 #include <net/route.h>
 #include <net/ipv6.h>
 #include <net/ip6_fib.h>
@@ -279,6 +279,7 @@ struct xfrm_type
         __u8                    proto;
         __u8                    flags;
 #define XFRM_TYPE_NON_FRAGMENT  1
+#define XFRM_TYPE_REPLAY_PROT   2
 
         int                     (*init_state)(struct xfrm_state *x);
         void                    (*destructor)(struct xfrm_state *);
@@ -419,6 +420,23 @@ extern int xfrm_unregister_km(struct xfrm_mgr *km);
 
 extern unsigned int xfrm_policy_count[XFRM_POLICY_MAX*2];
 
+/*
+ * This structure is used for the duration where packets are being
+ * transformed by IPsec.  As soon as the packet leaves IPsec the
+ * area beyond the generic IP part may be overwritten.
+ */
+struct xfrm_skb_cb {
+        union {
+                struct inet_skb_parm h4;
+                struct inet6_skb_parm h6;
+        } header;
+
+        /* Sequence number for replay protection. */
+        u64 seq;
+};
+
+#define XFRM_SKB_CB(__skb) ((struct xfrm_skb_cb *)&((__skb)->cb[0]))
+
 /* Audit Information */
 struct xfrm_audit
 {
diff --git a/net/ipv4/ah4.c b/net/ipv4/ah4.c
index dc1d8e871b24..58af298e1941 100644
--- a/net/ipv4/ah4.c
+++ b/net/ipv4/ah4.c
@@ -96,8 +96,7 @@ static int ah_output(struct xfrm_state *x, struct sk_buff *skb)
 
         ah->reserved = 0;
         ah->spi = x->id.spi;
-        ah->seq_no = htonl(++x->replay.oseq);
-        xfrm_aevent_doreplay(x);
+        ah->seq_no = htonl(XFRM_SKB_CB(skb)->seq);
         err = ah_mac_digest(ahp, skb, ah->auth_data);
         if (err)
                 goto error;
@@ -297,6 +296,7 @@ static struct xfrm_type ah_type =
         .description    = "AH4",
         .owner          = THIS_MODULE,
         .proto          = IPPROTO_AH,
+        .flags          = XFRM_TYPE_REPLAY_PROT,
         .init_state     = ah_init_state,
         .destructor     = ah_destroy,
         .input          = ah_input,
diff --git a/net/ipv4/esp4.c b/net/ipv4/esp4.c
index d233e2e62500..0f62af9a7f15 100644
--- a/net/ipv4/esp4.c
+++ b/net/ipv4/esp4.c
@@ -95,8 +95,7 @@ static int esp_output(struct xfrm_state *x, struct sk_buff *skb)
                 top_iph->protocol = IPPROTO_ESP;
 
         esph->spi = x->id.spi;
-        esph->seq_no = htonl(++x->replay.oseq);
-        xfrm_aevent_doreplay(x);
+        esph->seq_no = htonl(XFRM_SKB_CB(skb)->seq);
 
         if (esp->conf.ivlen) {
                 if (unlikely(!esp->conf.ivinitted)) {
@@ -437,6 +436,7 @@ static struct xfrm_type esp_type =
         .description    = "ESP4",
         .owner          = THIS_MODULE,
         .proto          = IPPROTO_ESP,
+        .flags          = XFRM_TYPE_REPLAY_PROT,
         .init_state     = esp_init_state,
         .destructor     = esp_destroy,
         .get_mtu        = esp4_get_mtu,
diff --git a/net/ipv6/ah6.c b/net/ipv6/ah6.c
index 69a2030407b8..ae68a900f605 100644
--- a/net/ipv6/ah6.c
+++ b/net/ipv6/ah6.c
@@ -283,8 +283,7 @@ static int ah6_output(struct xfrm_state *x, struct sk_buff *skb)
 
         ah->reserved = 0;
         ah->spi = x->id.spi;
-        ah->seq_no = htonl(++x->replay.oseq);
-        xfrm_aevent_doreplay(x);
+        ah->seq_no = htonl(XFRM_SKB_CB(skb)->seq);
         err = ah_mac_digest(ahp, skb, ah->auth_data);
         if (err)
                 goto error_free_iph;
@@ -506,6 +505,7 @@ static struct xfrm_type ah6_type =
         .description    = "AH6",
         .owner          = THIS_MODULE,
         .proto          = IPPROTO_AH,
+        .flags          = XFRM_TYPE_REPLAY_PROT,
         .init_state     = ah6_init_state,
         .destructor     = ah6_destroy,
         .input          = ah6_input,
diff --git a/net/ipv6/esp6.c b/net/ipv6/esp6.c
index 77281068d0f9..0c5fb81451b7 100644
--- a/net/ipv6/esp6.c
+++ b/net/ipv6/esp6.c
@@ -95,8 +95,7 @@ static int esp6_output(struct xfrm_state *x, struct sk_buff *skb)
         *skb_network_header(skb) = IPPROTO_ESP;
 
         esph->spi = x->id.spi;
-        esph->seq_no = htonl(++x->replay.oseq);
-        xfrm_aevent_doreplay(x);
+        esph->seq_no = htonl(XFRM_SKB_CB(skb)->seq);
 
         if (esp->conf.ivlen) {
                 if (unlikely(!esp->conf.ivinitted)) {
@@ -373,6 +372,7 @@ static struct xfrm_type esp6_type =
         .description    = "ESP6",
         .owner          = THIS_MODULE,
         .proto          = IPPROTO_ESP,
+        .flags          = XFRM_TYPE_REPLAY_PROT,
         .init_state     = esp6_init_state,
         .destructor     = esp6_destroy,
         .get_mtu        = esp6_get_mtu,
diff --git a/net/xfrm/xfrm_output.c b/net/xfrm/xfrm_output.c
index 5b1c978a323c..20e789d8c63e 100644
--- a/net/xfrm/xfrm_output.c
+++ b/net/xfrm/xfrm_output.c
@@ -58,6 +58,11 @@ int xfrm_output(struct sk_buff *skb)
                 if (err)
                         goto error;
 
+                if (x->type->flags & XFRM_TYPE_REPLAY_PROT) {
+                        XFRM_SKB_CB(skb)->seq = ++x->replay.oseq;
+                        xfrm_aevent_doreplay(x);
+                }
+
                 err = x->mode->output(x, skb);
                 if (err)
                         goto error;