[PATCH 10/16 net-next v2] tunnels: guard IPv4 tunnel functions with CONFIG_IPV4

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

To enable compiling INET subsystem withou IPv4, IPv4 specific IP tunnel
core functions must be bypassed when the protocol is disabled.

Signed-off-by: Fernando Fernandez Mancera <fmancera@suse.de>
---
 net/ipv4/ip_tunnel_core.c | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/net/ipv4/ip_tunnel_core.c b/net/ipv4/ip_tunnel_core.c
index bab42b9e277f..996e61243922 100644
--- a/net/ipv4/ip_tunnel_core.c
+++ b/net/ipv4/ip_tunnel_core.c
@@ -58,6 +58,14 @@ void iptunnel_xmit(struct sock *sk, struct rtable *rt, struct sk_buff *skb,
 	struct iphdr *iph;
 	int err;
 
+	if (!IS_ENABLED(CONFIG_IPV4)) {
+		if (dev)
+			DEV_STATS_INC(dev, tx_errors);
+		ip_rt_put(rt);
+		kfree_skb(skb);
+		return;
+	}
+
 	if (unlikely(dev_recursion_level() > IP_TUNNEL_RECURSION_LIMIT)) {
 		if (dev) {
 			net_crit_ratelimited("Dead loop on virtual device %s (net %llu), fix it urgently!\n",
@@ -218,6 +226,9 @@ static int iptunnel_pmtud_build_icmp(struct sk_buff *skb, int mtu)
 	struct ethhdr eh;
 	int len, err;
 
+	if (!IS_ENABLED(CONFIG_IPV4))
+		return -EOPNOTSUPP;
+
 	if (!pskb_may_pull(skb, ETH_HLEN + sizeof(struct iphdr)))
 		return -EINVAL;
 
-- 
2.55.0