xfrm: ifdef setsockopt(UDP_ENCAP_ESPINUDP/UDP_ENCAP_ESPINUDP_NON_IKE)

If IPsec is not configured, there is no reason to delay the inevitable.

Signed-off-by: Alexey Dobriyan <[e-mail]>
Signed-off-by: Steffen Klassert <[e-mail]>

include/net/xfrm.h

···
 {
  	return -ENOPROTOOPT;
 }
-
-static inline int xfrm4_udp_encap_rcv(struct sock *sk, struct sk_buff *skb)
-{
- 	/* should not happen */
- 	kfree_skb(skb);
-	return 0;
-}
 #endif
 
 struct dst_entry *__xfrm_dst_lookup(struct net *net, int tos, int oif,

net/ipv4/udp.c

···
 	case UDP_ENCAP:
 		switch (val) {
 		case 0:
+#ifdef CONFIG_XFRM
 		case UDP_ENCAP_ESPINUDP:
 		case UDP_ENCAP_ESPINUDP_NON_IKE:
 			up->encap_rcv = xfrm4_udp_encap_rcv;
+#endif
 			/* FALLTHROUGH */
 		case UDP_ENCAP_L2TPINUDP:
 			up->encap_type = val;