[IPSEC]: Add async resume support on input

This patch adds support for async resumptions on input.  To do so, the
transform would return -EINPROGRESS and subsequently invoke the
function xfrm_input_resume to resume processing.

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

4 files changed, 40 insertions, 5 deletions

diff --git a/include/net/xfrm.h b/include/net/xfrm.h
index cf85dc9dc420..37a086d71baf 100644
--- a/include/net/xfrm.h
+++ b/include/net/xfrm.h
@@ -1138,6 +1138,7 @@ extern int xfrm_init_state(struct xfrm_state *x);
 extern int xfrm_prepare_input(struct xfrm_state *x, struct sk_buff *skb);
 extern int xfrm_input(struct sk_buff *skb, int nexthdr, __be32 spi,
                       int encap_type);
+extern int xfrm_input_resume(struct sk_buff *skb, int nexthdr);
 extern int xfrm_output_resume(struct sk_buff *skb, int err);
 extern int xfrm_output(struct sk_buff *skb);
 extern int xfrm4_extract_header(struct sk_buff *skb);
diff --git a/net/ipv4/xfrm4_input.c b/net/ipv4/xfrm4_input.c
index 662d1e86cfbf..d5890c84a492 100644
--- a/net/ipv4/xfrm4_input.c
+++ b/net/ipv4/xfrm4_input.c
@@ -59,6 +59,9 @@ int xfrm4_transport_finish(struct sk_buff *skb, int async)
                 xfrm4_rcv_encap_finish);
         return 0;
 #else
+        if (async)
+                return xfrm4_rcv_encap_finish(skb);
+
         return -iph->protocol;
 #endif
 }
diff --git a/net/ipv6/xfrm6_input.c b/net/ipv6/xfrm6_input.c
index 5c006c845943..e317d0855468 100644
--- a/net/ipv6/xfrm6_input.c
+++ b/net/ipv6/xfrm6_input.c
@@ -41,6 +41,9 @@ int xfrm6_transport_finish(struct sk_buff *skb, int async)
                 ip6_rcv_finish);
         return -1;
 #else
+        if (async)
+                return ip6_rcv_finish(skb);
+
         return 1;
 #endif
 }
diff --git a/net/xfrm/xfrm_input.c b/net/xfrm/xfrm_input.c
index cce9d4586045..96f42c1d2e8e 100644
--- a/net/xfrm/xfrm_input.c
+++ b/net/xfrm/xfrm_input.c
@@ -101,8 +101,17 @@ int xfrm_input(struct sk_buff *skb, int nexthdr, __be32 spi, int encap_type)
         int err;
         __be32 seq;
         struct xfrm_state *x;
+        xfrm_address_t *daddr;
         int decaps = 0;
-        unsigned int daddroff = XFRM_SPI_SKB_CB(skb)->daddroff;
+        int async = 0;
+
+        /* A negative encap_type indicates async resumption. */
+        if (encap_type < 0) {
+                async = 1;
+                x = skb->sp->xvec[skb->sp->len - 1];
+                seq = XFRM_SKB_CB(skb)->seq;
+                goto resume;
+        }
 
         /* Allocate new secpath or COW existing one. */
         if (!skb->sp || atomic_read(&skb->sp->refcnt) != 1) {
@@ -116,6 +125,9 @@ int xfrm_input(struct sk_buff *skb, int nexthdr, __be32 spi, int encap_type)
                 skb->sp = sp;
         }
 
+        daddr = (xfrm_address_t *)(skb_network_header(skb) +
+                                   XFRM_SPI_SKB_CB(skb)->daddroff);
+
         seq = 0;
         if (!spi && (err = xfrm_parse_spi(skb, nexthdr, &spi, &seq)) != 0)
                 goto drop;
@@ -124,9 +136,7 @@ int xfrm_input(struct sk_buff *skb, int nexthdr, __be32 spi, int encap_type)
                 if (skb->sp->len == XFRM_MAX_DEPTH)
                         goto drop;
 
-                x = xfrm_state_lookup((xfrm_address_t *)
-                                      (skb_network_header(skb) + daddroff),
-                                      spi, nexthdr, AF_INET);
+                x = xfrm_state_lookup(daddr, spi, nexthdr, AF_INET);
                 if (x == NULL)
                         goto drop;
 
@@ -147,8 +157,14 @@ int xfrm_input(struct sk_buff *skb, int nexthdr, __be32 spi, int encap_type)
 
                 spin_unlock(&x->lock);
 
+                XFRM_SKB_CB(skb)->seq = seq;
+
                 nexthdr = x->type->input(x, skb);
 
+                if (nexthdr == -EINPROGRESS)
+                        return 0;
+
+resume:
                 spin_lock(&x->lock);
                 if (nexthdr <= 0) {
                         if (nexthdr == -EBADMSG)
@@ -177,6 +193,12 @@ int xfrm_input(struct sk_buff *skb, int nexthdr, __be32 spi, int encap_type)
                         break;
                 }
 
+                /*
+                 * We need the inner address.  However, we only get here for
+                 * transport mode so the outer address is identical.
+                 */
+                daddr = &x->id.daddr;
+
                 err = xfrm_parse_spi(skb, nexthdr, &spi, &seq);
                 if (err < 0)
                         goto drop;
@@ -190,7 +212,7 @@ int xfrm_input(struct sk_buff *skb, int nexthdr, __be32 spi, int encap_type)
                 netif_rx(skb);
                 return 0;
         } else {
-                return x->inner_mode->afinfo->transport_finish(skb, 0);
+                return x->inner_mode->afinfo->transport_finish(skb, async);
         }
 
 drop_unlock:
@@ -201,6 +223,12 @@ drop:
 }
 EXPORT_SYMBOL(xfrm_input);
 
+int xfrm_input_resume(struct sk_buff *skb, int nexthdr)
+{
+        return xfrm_input(skb, nexthdr, 0, -1);
+}
+EXPORT_SYMBOL(xfrm_input_resume);
+
 void __init xfrm_input_init(void)
 {
         secpath_cachep = kmem_cache_create("secpath_cache",