netfilter: move handlers to net/ip_vs.h

Fix the following compilation warnings:
net/netfilter/ipvs/ip_vs_proto_tcp.c:147:1: warning: no previous prototype for 'tcp_snat_handler' [-Wmissing-prototypes]
  147 | tcp_snat_handler(struct sk_buff *skb, struct ip_vs_protocol *pp,
      | ^~~~~~~~~~~~~~~~
net/netfilter/ipvs/ip_vs_proto_udp.c:136:1: warning: no previous prototype for 'udp_snat_handler' [-Wmissing-prototypes]
  136 | udp_snat_handler(struct sk_buff *skb, struct ip_vs_protocol *pp,
      | ^~~~~~~~~~~~~~~~
Signed-off-by: Leon Romanovsky <leonro@nvidia.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

include/net/ip_vs.h

@@ -1712,4 +1712,15 @@ ip_vs_dest_conn_overhead(struct ip_vs_dest *dest)
 		atomic_read(&dest->inactconns);
 }
 
+#ifdef CONFIG_IP_VS_PROTO_TCP
+INDIRECT_CALLABLE_DECLARE(int
+	tcp_snat_handler(struct sk_buff *skb, struct ip_vs_protocol *pp,
+			 struct ip_vs_conn *cp, struct ip_vs_iphdr *iph));
+#endif
+
+#ifdef CONFIG_IP_VS_PROTO_UDP
+INDIRECT_CALLABLE_DECLARE(int
+	udp_snat_handler(struct sk_buff *skb, struct ip_vs_protocol *pp,
+			 struct ip_vs_conn *cp, struct ip_vs_iphdr *iph));
+#endif
 #endif	/* _NET_IP_VS_H */

net/netfilter/ipvs/ip_vs_core.c

@@ -68,18 +68,6 @@ EXPORT_SYMBOL(ip_vs_get_debug_level);
 #endif
 EXPORT_SYMBOL(ip_vs_new_conn_out);
 
-#ifdef CONFIG_IP_VS_PROTO_TCP
-INDIRECT_CALLABLE_DECLARE(int
-	tcp_snat_handler(struct sk_buff *skb, struct ip_vs_protocol *pp,
-			 struct ip_vs_conn *cp, struct ip_vs_iphdr *iph));
-#endif
-
-#ifdef CONFIG_IP_VS_PROTO_UDP
-INDIRECT_CALLABLE_DECLARE(int
-	udp_snat_handler(struct sk_buff *skb, struct ip_vs_protocol *pp,
-			 struct ip_vs_conn *cp, struct ip_vs_iphdr *iph));
-#endif
-
 #if defined(CONFIG_IP_VS_PROTO_TCP) && defined(CONFIG_IP_VS_PROTO_UDP)
 #define SNAT_CALL(f, ...) \
 	INDIRECT_CALL_2(f, tcp_snat_handler, udp_snat_handler, __VA_ARGS__)