[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>
diff --git a/net/ipv4/xfrm4_policy.c b/net/ipv4/xfrm4_policy.c
index 10b72d1..5ccae3a 100644
--- a/net/ipv4/xfrm4_policy.c
+++ b/net/ipv4/xfrm4_policy.c
@@ -115,7 +115,7 @@
}
static void
-_decode_session4(struct sk_buff *skb, struct flowi *fl)
+_decode_session4(struct sk_buff *skb, struct flowi *fl, int reverse)
{
struct iphdr *iph = ip_hdr(skb);
u8 *xprth = skb_network_header(skb) + iph->ihl * 4;
@@ -131,8 +131,8 @@
if (pskb_may_pull(skb, xprth + 4 - skb->data)) {
__be16 *ports = (__be16 *)xprth;
- fl->fl_ip_sport = ports[0];
- fl->fl_ip_dport = ports[1];
+ fl->fl_ip_sport = ports[!!reverse];
+ fl->fl_ip_dport = ports[!reverse];
}
break;
@@ -174,8 +174,8 @@
}
}
fl->proto = iph->protocol;
- fl->fl4_dst = iph->daddr;
- fl->fl4_src = iph->saddr;
+ fl->fl4_dst = reverse ? iph->saddr : iph->daddr;
+ fl->fl4_src = reverse ? iph->daddr : iph->saddr;
fl->fl4_tos = iph->tos;
}