[IPSEC]: Merge most of the input path

As part of the work on asynchronous cryptographic operations, we need
to be able to resume from the spot where they occur.  As such, it
helps if we isolate them to one spot.

This patch moves most of the remaining family-specific processing into
the common input code.

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

1 files changed, 113 insertions, 0 deletions

diff --git a/net/xfrm/xfrm_input.c b/net/xfrm/xfrm_input.c
index 4c803f7e74e5..b980095be935 100644
--- a/net/xfrm/xfrm_input.c
+++ b/net/xfrm/xfrm_input.c
@@ -9,6 +9,8 @@
 
 #include <linux/slab.h>
 #include <linux/module.h>
+#include <linux/netdevice.h>
+#include <net/dst.h>
 #include <net/ip.h>
 #include <net/xfrm.h>
 
@@ -94,6 +96,117 @@ int xfrm_prepare_input(struct xfrm_state *x, struct sk_buff *skb)
 }
 EXPORT_SYMBOL(xfrm_prepare_input);
 
+int xfrm_input(struct sk_buff *skb, int nexthdr, __be32 spi, int encap_type)
+{
+	int err;
+	__be32 seq;
+	struct xfrm_state *xfrm_vec[XFRM_MAX_DEPTH];
+	struct xfrm_state *x;
+	int xfrm_nr = 0;
+	int decaps = 0;
+	unsigned int nhoff = XFRM_SPI_SKB_CB(skb)->nhoff;
+	unsigned int daddroff = XFRM_SPI_SKB_CB(skb)->daddroff;
+
+	seq = 0;
+	if (!spi && (err = xfrm_parse_spi(skb, nexthdr, &spi, &seq)) != 0)
+		goto drop;
+
+	do {
+		if (xfrm_nr == XFRM_MAX_DEPTH)
+			goto drop;
+
+		x = xfrm_state_lookup((xfrm_address_t *)
+				      (skb_network_header(skb) + daddroff),
+				      spi, nexthdr, AF_INET);
+		if (x == NULL)
+			goto drop;
+
+		spin_lock(&x->lock);
+		if (unlikely(x->km.state != XFRM_STATE_VALID))
+			goto drop_unlock;
+
+		if ((x->encap ? x->encap->encap_type : 0) != encap_type)
+			goto drop_unlock;
+
+		if (x->props.replay_window && xfrm_replay_check(x, seq))
+			goto drop_unlock;
+
+		if (xfrm_state_check_expire(x))
+			goto drop_unlock;
+
+		nexthdr = x->type->input(x, skb);
+		if (nexthdr <= 0)
+			goto drop_unlock;
+
+		skb_network_header(skb)[nhoff] = nexthdr;
+
+		/* only the first xfrm gets the encap type */
+		encap_type = 0;
+
+		if (x->props.replay_window)
+			xfrm_replay_advance(x, seq);
+
+		x->curlft.bytes += skb->len;
+		x->curlft.packets++;
+
+		spin_unlock(&x->lock);
+
+		xfrm_vec[xfrm_nr++] = x;
+
+		if (x->inner_mode->input(x, skb))
+			goto drop;
+
+		if (x->outer_mode->flags & XFRM_MODE_FLAG_TUNNEL) {
+			decaps = 1;
+			break;
+		}
+
+		err = xfrm_parse_spi(skb, nexthdr, &spi, &seq);
+		if (err < 0)
+			goto drop;
+	} while (!err);
+
+	/* Allocate new secpath or COW existing one. */
+
+	if (!skb->sp || atomic_read(&skb->sp->refcnt) != 1) {
+		struct sec_path *sp;
+		sp = secpath_dup(skb->sp);
+		if (!sp)
+			goto drop;
+		if (skb->sp)
+			secpath_put(skb->sp);
+		skb->sp = sp;
+	}
+	if (xfrm_nr + skb->sp->len > XFRM_MAX_DEPTH)
+		goto drop;
+
+	memcpy(skb->sp->xvec + skb->sp->len, xfrm_vec,
+	       xfrm_nr * sizeof(xfrm_vec[0]));
+	skb->sp->len += xfrm_nr;
+
+	nf_reset(skb);
+
+	if (decaps) {
+		dst_release(skb->dst);
+		skb->dst = NULL;
+		netif_rx(skb);
+		return 0;
+	} else {
+		return x->inner_mode->afinfo->transport_finish(skb, 0);
+	}
+
+drop_unlock:
+	spin_unlock(&x->lock);
+	xfrm_state_put(x);
+drop:
+	while (--xfrm_nr >= 0)
+		xfrm_state_put(xfrm_vec[xfrm_nr]);
+
+	kfree_skb(skb);
+	return 0;
+}
+EXPORT_SYMBOL(xfrm_input);
+
 void __init xfrm_input_init(void)
 {
 	secpath_cachep = kmem_cache_create("secpath_cache",