netns xfrm: deal with dst entries in netns

GC is non-existent in netns, so after you hit GC threshold, no new
dst entries will be created until someone triggers cleanup in init_net.

Make xfrm4_dst_ops and xfrm6_dst_ops per-netns.
This is not done in a generic way, because it woule waste
(AF_MAX - 2) * sizeof(struct dst_ops) bytes per-netns.

Reorder GC threshold initialization so it'd be done before registering
XFRM policies.

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 8 insertions, 6 deletions

diff --git a/net/ipv4/xfrm4_policy.c b/net/ipv4/xfrm4_policy.c
index 8c08a28d8f83..67107d63c1cd 100644
--- a/net/ipv4/xfrm4_policy.c
+++ b/net/ipv4/xfrm4_policy.c
@@ -15,7 +15,6 @@
 #include <net/xfrm.h>
 #include <net/ip.h>
 
-static struct dst_ops xfrm4_dst_ops;
 static struct xfrm_policy_afinfo xfrm4_policy_afinfo;
 
 static struct dst_entry *xfrm4_dst_lookup(struct net *net, int tos,
@@ -190,8 +189,10 @@ _decode_session4(struct sk_buff *skb, struct flowi *fl, int reverse)
 
 static inline int xfrm4_garbage_collect(struct dst_ops *ops)
 {
-        xfrm4_policy_afinfo.garbage_collect(&init_net);
-        return (atomic_read(&xfrm4_dst_ops.entries) > xfrm4_dst_ops.gc_thresh*2);
+        struct net *net = container_of(ops, struct net, xfrm.xfrm4_dst_ops);
+
+        xfrm4_policy_afinfo.garbage_collect(net);
+        return (atomic_read(&ops->entries) > ops->gc_thresh * 2);
 }
 
 static void xfrm4_update_pmtu(struct dst_entry *dst, u32 mtu)
@@ -268,7 +269,7 @@ static struct xfrm_policy_afinfo xfrm4_policy_afinfo = {
 static struct ctl_table xfrm4_policy_table[] = {
         {
                 .procname       = "xfrm4_gc_thresh",
-                .data           = &xfrm4_dst_ops.gc_thresh,
+                .data           = &init_net.xfrm.xfrm4_dst_ops.gc_thresh,
                 .maxlen         = sizeof(int),
                 .mode           = 0644,
                 .proc_handler   = proc_dointvec,
@@ -295,8 +296,6 @@ static void __exit xfrm4_policy_fini(void)
 
 void __init xfrm4_init(int rt_max_size)
 {
-        xfrm4_state_init();
-        xfrm4_policy_init();
         /*
          * Select a default value for the gc_thresh based on the main route
          * table hash size.  It seems to me the worst case scenario is when
@@ -308,6 +307,9 @@ void __init xfrm4_init(int rt_max_size)
          * and start cleaning when were 1/2 full
          */
         xfrm4_dst_ops.gc_thresh = rt_max_size/2;
+
+        xfrm4_state_init();
+        xfrm4_policy_init();
 #ifdef CONFIG_SYSCTL
         sysctl_hdr = register_net_sysctl_table(&init_net, net_ipv4_ctl_path,
                                                 xfrm4_policy_table);