[IPSEC]: Move tunnel parsing for IPv4 out of xfrm4_input

This patch moves the tunnel parsing for IPv4 out of xfrm4_input and into
xfrm4_tunnel.  This change is in line with what IPv6 does and will allow
us to merge the two input functions.

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

2 files changed, 18 insertions, 27 deletions

diff --git a/net/ipv4/xfrm4_input.c b/net/ipv4/xfrm4_input.c
index e9bbfde19ac3..5cb0b5995bc8 100644
--- a/net/ipv4/xfrm4_input.c
+++ b/net/ipv4/xfrm4_input.c
@@ -16,19 +16,6 @@
 #include <net/ip.h>
 #include <net/xfrm.h>
 
-static int xfrm4_parse_spi(struct sk_buff *skb, u8 nexthdr, __be32 *spi, __be32 *seq)
-{
-        switch (nexthdr) {
-        case IPPROTO_IPIP:
-        case IPPROTO_IPV6:
-                *spi = ip_hdr(skb)->saddr;
-                *seq = 0;
-                return 0;
-        }
-
-        return xfrm_parse_spi(skb, nexthdr, spi, seq);
-}
-
 #ifdef CONFIG_NETFILTER
 static inline int xfrm4_rcv_encap_finish(struct sk_buff *skb)
 {
@@ -46,28 +33,29 @@ drop:
 }
 #endif
 
-static int xfrm4_rcv_encap(struct sk_buff *skb, __u16 encap_type)
+int xfrm4_rcv_encap(struct sk_buff *skb, int nexthdr, __be32 spi,
+                    int encap_type)
 {
-        __be32 spi, seq;
+        int err;
+        __be32 seq;
         struct xfrm_state *xfrm_vec[XFRM_MAX_DEPTH];
         struct xfrm_state *x;
         int xfrm_nr = 0;
         int decaps = 0;
-        int err = xfrm4_parse_spi(skb, ip_hdr(skb)->protocol, &spi, &seq);
         unsigned int nhoff = offsetof(struct iphdr, protocol);
 
-        if (err != 0)
+        seq = 0;
+        if (!spi && (err = xfrm_parse_spi(skb, nexthdr, &spi, &seq)) != 0)
                 goto drop;
 
         do {
                 const struct iphdr *iph = ip_hdr(skb);
-                int nexthdr;
 
                 if (xfrm_nr == XFRM_MAX_DEPTH)
                         goto drop;
 
                 x = xfrm_state_lookup((xfrm_address_t *)&iph->daddr, spi,
-                                iph->protocol != IPPROTO_IPV6 ? iph->protocol : IPPROTO_IPIP, AF_INET);
+                                      nexthdr, AF_INET);
                 if (x == NULL)
                         goto drop;
 
@@ -111,7 +99,7 @@ static int xfrm4_rcv_encap(struct sk_buff *skb, __u16 encap_type)
                         break;
                 }
 
-                err = xfrm_parse_spi(skb, ip_hdr(skb)->protocol, &spi, &seq);
+                err = xfrm_parse_spi(skb, nexthdr, &spi, &seq);
                 if (err < 0)
                         goto drop;
         } while (!err);
@@ -165,6 +153,7 @@ drop:
         kfree_skb(skb);
         return 0;
 }
+EXPORT_SYMBOL(xfrm4_rcv_encap);
 
 /* If it's a keepalive packet, then just eat it.
  * If it's an encapsulated packet, then pass it to the
@@ -252,11 +241,8 @@ int xfrm4_udp_encap_rcv(struct sock *sk, struct sk_buff *skb)
         __skb_pull(skb, len);
         skb_reset_transport_header(skb);
 
-        /* modify the protocol (it's ESP!) */
-        iph->protocol = IPPROTO_ESP;
-
         /* process ESP */
-        ret = xfrm4_rcv_encap(skb, encap_type);
+        ret = xfrm4_rcv_encap(skb, IPPROTO_ESP, 0, encap_type);
         return ret;
 
 drop:
@@ -266,7 +252,7 @@ drop:
 
 int xfrm4_rcv(struct sk_buff *skb)
 {
-        return xfrm4_rcv_encap(skb, 0);
+        return xfrm4_rcv_spi(skb, ip_hdr(skb)->protocol, 0);
 }
 
 EXPORT_SYMBOL(xfrm4_rcv);
diff --git a/net/ipv4/xfrm4_tunnel.c b/net/ipv4/xfrm4_tunnel.c
index 83e9580feac4..326845195620 100644
--- a/net/ipv4/xfrm4_tunnel.c
+++ b/net/ipv4/xfrm4_tunnel.c
@@ -48,20 +48,25 @@ static struct xfrm_type ipip_type = {
         .output         = ipip_output
 };
 
+static int xfrm_tunnel_rcv(struct sk_buff *skb)
+{
+        return xfrm4_rcv_spi(skb, IPPROTO_IP, ip_hdr(skb)->saddr);
+}
+
 static int xfrm_tunnel_err(struct sk_buff *skb, u32 info)
 {
         return -ENOENT;
 }
 
 static struct xfrm_tunnel xfrm_tunnel_handler = {
-        .handler        =       xfrm4_rcv,
+        .handler        =       xfrm_tunnel_rcv,
         .err_handler    =       xfrm_tunnel_err,
         .priority       =       2,
 };
 
 #if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
 static struct xfrm_tunnel xfrm64_tunnel_handler = {
-        .handler        =       xfrm4_rcv,
+        .handler        =       xfrm_tunnel_rcv,
         .err_handler    =       xfrm_tunnel_err,
         .priority       =       2,
 };