ipv6: Move ipv6_find_hdr() out of Netfilter code.

Open vSwitch will soon also use ipv6_find_hdr() so this moves it
out of Netfilter-specific code into a more common location.

Signed-off-by: Jesse Gross <jesse@nicira.com>
diff --git a/include/net/ipv6.h b/include/net/ipv6.h
index 979bf6c..b2f0cfb 100644
--- a/include/net/ipv6.h
+++ b/include/net/ipv6.h
@@ -630,6 +630,15 @@
 
 extern bool			ipv6_ext_hdr(u8 nexthdr);
 
+enum {
+	IP6_FH_F_FRAG	= (1 << 0),
+	IP6_FH_F_AUTH	= (1 << 1),
+};
+
+/* find specified header and get offset to it */
+extern int ipv6_find_hdr(const struct sk_buff *skb, unsigned int *offset,
+			 int target, unsigned short *fragoff, int *fragflg);
+
 extern int ipv6_find_tlv(struct sk_buff *skb, int offset, int type);
 
 extern struct in6_addr *fl6_update_dst(struct flowi6 *fl6,