tunnels: correct conditional build of MPLS and IPv6
Using a combination if #if conditionals and goto labels to unwind
tunnel4_init seems unwieldy. This patch takes a simpler approach of
directly unregistering previously registered protocols when an error
occurs.
This fixes a number of problems with the current implementation
including the potential presence of labels when they are unused
and the potential absence of unregister code when it is needed.
Fixes: 8afe97e5d416 ("tunnels: support MPLS over IPv4 tunnels")
Signed-off-by: Simon Horman <simon.horman@netronome.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv4/tunnel4.c b/net/ipv4/tunnel4.c
index 45cd4253..ec35eaa 100644
--- a/net/ipv4/tunnel4.c
+++ b/net/ipv4/tunnel4.c
@@ -208,24 +208,25 @@
static int __init tunnel4_init(void)
{
if (inet_add_protocol(&tunnel4_protocol, IPPROTO_IPIP))
- goto err_ipip;
+ goto err;
#if IS_ENABLED(CONFIG_IPV6)
- if (inet_add_protocol(&tunnel64_protocol, IPPROTO_IPV6))
- goto err_ipv6;
+ if (inet_add_protocol(&tunnel64_protocol, IPPROTO_IPV6)) {
+ inet_del_protocol(&tunnel4_protocol, IPPROTO_IPIP);
+ goto err;
+ }
#endif
#if IS_ENABLED(CONFIG_MPLS)
- if (inet_add_protocol(&tunnelmpls4_protocol, IPPROTO_MPLS))
- goto err_mpls;
+ if (inet_add_protocol(&tunnelmpls4_protocol, IPPROTO_MPLS)) {
+ inet_del_protocol(&tunnel4_protocol, IPPROTO_IPIP);
+#if IS_ENABLED(CONFIG_IPV6)
+ inet_del_protocol(&tunnel64_protocol, IPPROTO_IPV6);
+#endif
+ goto err;
+ }
#endif
return 0;
-#if IS_ENABLED(CONFIG_IPV6)
-err_mpls:
- inet_del_protocol(&tunnel4_protocol, IPPROTO_IPV6);
-#endif
-err_ipv6:
- inet_del_protocol(&tunnel4_protocol, IPPROTO_IPIP);
-err_ipip:
+err:
pr_err("%s: can't add protocol\n", __func__);
return -EAGAIN;
}