mpls: Add a sysctl to control the size of the mpls label table

This sysctl gives two benefits.  By defaulting the table size to 0
mpls even when compiled in and enabled defaults to not forwarding
any packets.  This prevents unpleasant surprises for users.

The other benefit is that as mpls labels are allocated locally a dense
table a small dense label table may be used which saves memory and
is extremely simple and efficient to implement.

This sysctl allows userspace to choose the restrictions on the label
table size userspace applications need to cope with.

Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 2 insertions, 0 deletions

diff --git a/include/net/netns/mpls.h b/include/net/netns/mpls.h
index f90aaf8d4f89..d29203651c01 100644
--- a/include/net/netns/mpls.h
+++ b/include/net/netns/mpls.h
@@ -6,10 +6,12 @@
 #define __NETNS_MPLS_H__
 
 struct mpls_route;
+struct ctl_table_header;
 
 struct netns_mpls {
         size_t platform_labels;
         struct mpls_route __rcu * __rcu *platform_label;
+        struct ctl_table_header *ctl;
 };
 
 #endif /* __NETNS_MPLS_H__ */