[PATCH 12/13 RFC net-next] netfilter: ipv4: guard ip_route_me_harder() with CONFIG_IPV4

[Fernando Fernandez Mancera <fmancera@suse.de>]

To enable compiling the network stack without IPv4, IPv4 specific packet
rerouting logic inside netfilter must be bypassed. Therefore, guard
ip_route_me_harder() with IS_ENABLED(CONFIG_IPV4) so it returns
-EPROTONOSUPPORT when IPv4 is disabled.

Signed-off-by: Fernando Fernandez Mancera <fmancera@suse.de>
---
 net/ipv4/netfilter.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/net/ipv4/netfilter.c b/net/ipv4/netfilter.c
index ce9e1bfa4259..9576d91bb6a6 100644
--- a/net/ipv4/netfilter.c
+++ b/net/ipv4/netfilter.c
@@ -21,6 +21,7 @@
 /* route_me_harder function, used by iptable_nat, iptable_mangle + ip_queue */
 int ip_route_me_harder(struct net *net, struct sock *sk, struct sk_buff *skb, unsigned int addr_type)
 {
+#if IS_ENABLED(CONFIG_IPV4)
 	struct net_device *dev = skb_dst_dev(skb);
 	const struct iphdr *iph = ip_hdr(skb);
 	struct rtable *rt;
@@ -85,6 +86,9 @@ int ip_route_me_harder(struct net *net, struct sock *sk, struct sk_buff *skb, un
 		return -ENOMEM;
 
 	return 0;
+#else
+	return -EPROTONOSUPPORT;
+#endif
 }
 EXPORT_SYMBOL(ip_route_me_harder);
 
-- 
2.54.0