[IPSEC]: Added xfrm_decode_session_reverse and xfrmX_policy_check_reverse

RFC 4301 requires us to relookup ICMP traffic that does not match any
policies using the reverse of its payload.  This patch adds the functions
xfrm_decode_session_reverse and xfrmX_policy_check_reverse so we can get
the reverse flow to perform such a lookup.

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

1 files changed, 5 insertions, 5 deletions

diff --git a/net/ipv6/xfrm6_policy.c b/net/ipv6/xfrm6_policy.c
index 181cf91538f1..d26b7dc3f33b 100644
--- a/net/ipv6/xfrm6_policy.c
+++ b/net/ipv6/xfrm6_policy.c
@@ -123,7 +123,7 @@ static int xfrm6_fill_dst(struct xfrm_dst *xdst, struct net_device *dev)
 }
 
 static inline void
-_decode_session6(struct sk_buff *skb, struct flowi *fl)
+_decode_session6(struct sk_buff *skb, struct flowi *fl, int reverse)
 {
         u16 offset = skb_network_header_len(skb);
         struct ipv6hdr *hdr = ipv6_hdr(skb);
@@ -132,8 +132,8 @@ _decode_session6(struct sk_buff *skb, struct flowi *fl)
         u8 nexthdr = nh[IP6CB(skb)->nhoff];
 
         memset(fl, 0, sizeof(struct flowi));
-        ipv6_addr_copy(&fl->fl6_dst, &hdr->daddr);
-        ipv6_addr_copy(&fl->fl6_src, &hdr->saddr);
+        ipv6_addr_copy(&fl->fl6_dst, reverse ? &hdr->saddr : &hdr->daddr);
+        ipv6_addr_copy(&fl->fl6_src, reverse ? &hdr->daddr : &hdr->saddr);
 
         while (pskb_may_pull(skb, nh + offset + 1 - skb->data)) {
                 nh = skb_network_header(skb);
@@ -156,8 +156,8 @@ _decode_session6(struct sk_buff *skb, struct flowi *fl)
                         if (pskb_may_pull(skb, nh + offset + 4 - skb->data)) {
                                 __be16 *ports = (__be16 *)exthdr;
 
-                                fl->fl_ip_sport = ports[0];
-                                fl->fl_ip_dport = ports[1];
+                                fl->fl_ip_sport = ports[!!reverse];
+                                fl->fl_ip_dport = ports[!reverse];
                         }
                         fl->proto = nexthdr;
                         return;