[PATCH 1/2] ipv6: hide ip6_encap_hlen/ip6_tnl_encap definitions

[PATCH 1/2] ipv6: hide ip6_encap_hlen/ip6_tnl_encap definitions

[Arnd Bergmann]

A recent cleanup moved MAX_IPTUN_ENCAP_OPS along with some other
definitions, but it is now invisible when CONFIG_INET is
not defined, but still referenced from ip6_tunnel.h:

In file included from net/xfrm/xfrm_input.c:17:0:
include/net/ip6_tunnel.h:67:17: error: 'MAX_IPTUN_ENCAP_OPS' undeclared here (not in a function)
   ip6tun_encaps[MAX_IPTUN_ENCAP_OPS];
                 ^~~~~~~~~~~~~~~~~~~

This hides the ip6_encap_hlen and ip6_tnl_encap functions inside
of CONFIG_INET so we don't run into the the problem.

Alternatively we could move the macro out of the #ifdef again to
restore the previous behavior

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Fixes: 55c2bc143224 ("net: Cleanup encap items in ip_tunnels.h")
---
 include/net/ip6_tunnel.h | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/include/net/ip6_tunnel.h b/include/net/ip6_tunnel.h
index d325c81332e3..43a5a0e4524c 100644
--- a/include/net/ip6_tunnel.h
+++ b/include/net/ip6_tunnel.h
@@ -63,6 +63,8 @@ struct ip6_tnl_encap_ops {
 			    u8 *protocol, struct flowi6 *fl6);
 };
 
+#ifdef CONFIG_INET
+
 extern const struct ip6_tnl_encap_ops __rcu *
 		ip6tun_encaps[MAX_IPTUN_ENCAP_OPS];
 
@@ -138,7 +140,6 @@ struct net *ip6_tnl_get_link_net(const struct net_device *dev);
 int ip6_tnl_get_iflink(const struct net_device *dev);
 int ip6_tnl_change_mtu(struct net_device *dev, int new_mtu);
 
-#ifdef CONFIG_INET
 static inline void ip6tunnel_xmit(struct sock *sk, struct sk_buff *skb,
 				  struct net_device *dev)
 {
-- 
2.7.0

[PATCH 2/2] fou: add Kconfig options for IPv6 support

[Arnd Bergmann]

A previous patch added the fou6.ko module, but that failed to link
in a couple of configurations:

net/built-in.o: In function `ip6_tnl_encap_add_fou_ops':
net/ipv6/fou6.c:88: undefined reference to `ip6_tnl_encap_add_ops'
net/ipv6/fou6.c:94: undefined reference to `ip6_tnl_encap_add_ops'
net/ipv6/fou6.c:97: undefined reference to `ip6_tnl_encap_del_ops'
net/built-in.o: In function `ip6_tnl_encap_del_fou_ops':
net/ipv6/fou6.c:106: undefined reference to `ip6_tnl_encap_del_ops'
net/ipv6/fou6.c:107: undefined reference to `ip6_tnl_encap_del_ops'

If CONFIG_IPV6=m, ip6_tnl_encap_add_ops/ip6_tnl_encap_del_ops
are in a module, but fou6.c can still be built-in, and that
obviously fails to link.

Also, if CONFIG_IPV6=y, but CONFIG_IPV6_TUNNEL=m or
CONFIG_IPV6_TUNNEL=n, the same problem happens for a different
reason.

This adds two new silent Kconfig symbols to work around both
problems:

- CONFIG_IPV6_FOU is now always set to 'm' if either CONFIG_NET_FOU=m
  or CONFIG_IPV6=m
- CONFIG_IPV6_FOU_TUNNEL is set implicitly when IPV6_FOU is enabled
  and NET_FOU_IP_TUNNELS is also turned out, and it will ensure
  that CONFIG_IPV6_TUNNEL is also available.

The options could be made user-visible as well, to give additional
room for configuration, but it seems easier not to bother users
with more choice here.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Fixes: aa3463d65e7b ("fou: Add encap ops for IPv6 tunnels")
---
 net/ipv6/Kconfig  | 9 +++++++++
 net/ipv6/Makefile | 2 +-
 net/ipv6/fou6.c   | 2 +-
 3 files changed, 11 insertions(+), 2 deletions(-)

diff --git a/net/ipv6/Kconfig b/net/ipv6/Kconfig
index 3f8411328de5..994608263260 100644
--- a/net/ipv6/Kconfig
+++ b/net/ipv6/Kconfig
@@ -232,6 +232,15 @@ config IPV6_GRE
 
 	  Saying M here will produce a module called ip6_gre. If unsure, say N.
 
+config IPV6_FOU
+	tristate
+	default NET_FOU && IPV6
+
+config IPV6_FOU_TUNNEL
+	tristate
+	default NET_FOU_IP_TUNNELS && IPV6_FOU
+	select INET6_TUNNEL
+
 config IPV6_MULTIPLE_TABLES
 	bool "IPv6: Multiple Routing Tables"
 	select FIB_RULES
diff --git a/net/ipv6/Makefile b/net/ipv6/Makefile
index 7ec3129c9ace..d42ca3d1197f 100644
--- a/net/ipv6/Makefile
+++ b/net/ipv6/Makefile
@@ -42,7 +42,7 @@ obj-$(CONFIG_IPV6_VTI) += ip6_vti.o
 obj-$(CONFIG_IPV6_SIT) += sit.o
 obj-$(CONFIG_IPV6_TUNNEL) += ip6_tunnel.o
 obj-$(CONFIG_IPV6_GRE) += ip6_gre.o
-obj-$(CONFIG_NET_FOU) += fou6.o
+obj-$(CONFIG_NET_FOU_IPV6_TUNNELS) += fou6.o
 
 obj-y += addrconf_core.o exthdrs_core.o ip6_checksum.o ip6_icmp.o
 obj-$(CONFIG_INET) += output_core.o protocol.o $(ipv6-offload)
diff --git a/net/ipv6/fou6.c b/net/ipv6/fou6.c
index c972d0b52579..9ea249b9451e 100644
--- a/net/ipv6/fou6.c
+++ b/net/ipv6/fou6.c
@@ -69,7 +69,7 @@ int gue6_build_header(struct sk_buff *skb, struct ip_tunnel_encap *e,
 }
 EXPORT_SYMBOL(gue6_build_header);
 
-#ifdef CONFIG_NET_FOU_IP_TUNNELS
+#if IS_ENABLED(CONFIG_IPV6_FOU_TUNNEL)
 
 static const struct ip6_tnl_encap_ops fou_ip6tun_ops = {
 	.encap_hlen = fou_encap_hlen,
-- 
2.7.0

Re: [PATCH 1/2] ipv6: hide ip6_encap_hlen/ip6_tnl_encap definitions

[David Miller]

From: Arnd Bergmann <arnd@arndb.de>
Date: Wed, 25 May 2016 16:50:45 +0200

> A recent cleanup moved MAX_IPTUN_ENCAP_OPS along with some other
> definitions, but it is now invisible when CONFIG_INET is
> not defined, but still referenced from ip6_tunnel.h:
> 
> In file included from net/xfrm/xfrm_input.c:17:0:
> include/net/ip6_tunnel.h:67:17: error: 'MAX_IPTUN_ENCAP_OPS' undeclared here (not in a function)
>    ip6tun_encaps[MAX_IPTUN_ENCAP_OPS];
>                  ^~~~~~~~~~~~~~~~~~~
> 
> This hides the ip6_encap_hlen and ip6_tnl_encap functions inside
> of CONFIG_INET so we don't run into the the problem.
> 
> Alternatively we could move the macro out of the #ifdef again to
> restore the previous behavior
> 
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
> Fixes: 55c2bc143224 ("net: Cleanup encap items in ip_tunnels.h")

Applied.

Re: [PATCH 2/2] fou: add Kconfig options for IPv6 support

[David Miller]

From: Arnd Bergmann <arnd@arndb.de>
Date: Wed, 25 May 2016 16:50:46 +0200

> A previous patch added the fou6.ko module, but that failed to link
> in a couple of configurations:
> 
> net/built-in.o: In function `ip6_tnl_encap_add_fou_ops':
> net/ipv6/fou6.c:88: undefined reference to `ip6_tnl_encap_add_ops'
> net/ipv6/fou6.c:94: undefined reference to `ip6_tnl_encap_add_ops'
> net/ipv6/fou6.c:97: undefined reference to `ip6_tnl_encap_del_ops'
> net/built-in.o: In function `ip6_tnl_encap_del_fou_ops':
> net/ipv6/fou6.c:106: undefined reference to `ip6_tnl_encap_del_ops'
> net/ipv6/fou6.c:107: undefined reference to `ip6_tnl_encap_del_ops'
> 
> If CONFIG_IPV6=m, ip6_tnl_encap_add_ops/ip6_tnl_encap_del_ops
> are in a module, but fou6.c can still be built-in, and that
> obviously fails to link.
> 
> Also, if CONFIG_IPV6=y, but CONFIG_IPV6_TUNNEL=m or
> CONFIG_IPV6_TUNNEL=n, the same problem happens for a different
> reason.
> 
> This adds two new silent Kconfig symbols to work around both
> problems:
> 
> - CONFIG_IPV6_FOU is now always set to 'm' if either CONFIG_NET_FOU=m
>   or CONFIG_IPV6=m
> - CONFIG_IPV6_FOU_TUNNEL is set implicitly when IPV6_FOU is enabled
>   and NET_FOU_IP_TUNNELS is also turned out, and it will ensure
>   that CONFIG_IPV6_TUNNEL is also available.
> 
> The options could be made user-visible as well, to give additional
> room for configuration, but it seems easier not to bother users
> with more choice here.
> 
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
> Fixes: aa3463d65e7b ("fou: Add encap ops for IPv6 tunnels")

Applied.