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, 56 insertions, 3 deletions

diff --git a/net/xfrm/xfrm_policy.c b/net/xfrm/xfrm_policy.c
index d2c8cb57ee4c..0ecb16a9a883 100644
--- a/net/xfrm/xfrm_policy.c
+++ b/net/xfrm/xfrm_policy.c
@@ -1309,15 +1309,28 @@ static inline int xfrm_get_tos(struct flowi *fl, int family)
         return tos;
 }
 
-static inline struct xfrm_dst *xfrm_alloc_dst(int family)
+static inline struct xfrm_dst *xfrm_alloc_dst(struct net *net, int family)
 {
         struct xfrm_policy_afinfo *afinfo = xfrm_policy_get_afinfo(family);
+        struct dst_ops *dst_ops;
         struct xfrm_dst *xdst;
 
         if (!afinfo)
                 return ERR_PTR(-EINVAL);
 
-        xdst = dst_alloc(afinfo->dst_ops) ?: ERR_PTR(-ENOBUFS);
+        switch (family) {
+        case AF_INET:
+                dst_ops = &net->xfrm.xfrm4_dst_ops;
+                break;
+#if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
+        case AF_INET6:
+                dst_ops = &net->xfrm.xfrm6_dst_ops;
+                break;
+#endif
+        default:
+                BUG();
+        }
+        xdst = dst_alloc(dst_ops) ?: ERR_PTR(-ENOBUFS);
 
         xfrm_policy_put_afinfo(afinfo);
 
@@ -1366,6 +1379,7 @@ static struct dst_entry *xfrm_bundle_create(struct xfrm_policy *policy,
                                             struct flowi *fl,
                                             struct dst_entry *dst)
 {
+        struct net *net = xp_net(policy);
         unsigned long now = jiffies;
         struct net_device *dev;
         struct dst_entry *dst_prev = NULL;
@@ -1389,7 +1403,7 @@ static struct dst_entry *xfrm_bundle_create(struct xfrm_policy *policy,
         dst_hold(dst);
 
         for (; i < nx; i++) {
-                struct xfrm_dst *xdst = xfrm_alloc_dst(family);
+                struct xfrm_dst *xdst = xfrm_alloc_dst(net, family);
                 struct dst_entry *dst1 = &xdst->u.dst;
 
                 err = PTR_ERR(xdst);
@@ -2279,6 +2293,7 @@ EXPORT_SYMBOL(xfrm_bundle_ok);
 
 int xfrm_policy_register_afinfo(struct xfrm_policy_afinfo *afinfo)
 {
+        struct net *net;
         int err = 0;
         if (unlikely(afinfo == NULL))
                 return -EINVAL;
@@ -2302,6 +2317,27 @@ int xfrm_policy_register_afinfo(struct xfrm_policy_afinfo *afinfo)
                 xfrm_policy_afinfo[afinfo->family] = afinfo;
         }
         write_unlock_bh(&xfrm_policy_afinfo_lock);
+
+        rtnl_lock();
+        for_each_net(net) {
+                struct dst_ops *xfrm_dst_ops;
+
+                switch (afinfo->family) {
+                case AF_INET:
+                        xfrm_dst_ops = &net->xfrm.xfrm4_dst_ops;
+                        break;
+#if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
+                case AF_INET6:
+                        xfrm_dst_ops = &net->xfrm.xfrm6_dst_ops;
+                        break;
+#endif
+                default:
+                        BUG();
+                }
+                *xfrm_dst_ops = *afinfo->dst_ops;
+        }
+        rtnl_unlock();
+
         return err;
 }
 EXPORT_SYMBOL(xfrm_policy_register_afinfo);
@@ -2332,6 +2368,22 @@ int xfrm_policy_unregister_afinfo(struct xfrm_policy_afinfo *afinfo)
 }
 EXPORT_SYMBOL(xfrm_policy_unregister_afinfo);
 
+static void __net_init xfrm_dst_ops_init(struct net *net)
+{
+        struct xfrm_policy_afinfo *afinfo;
+
+        read_lock_bh(&xfrm_policy_afinfo_lock);
+        afinfo = xfrm_policy_afinfo[AF_INET];
+        if (afinfo)
+                net->xfrm.xfrm4_dst_ops = *afinfo->dst_ops;
+#if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
+        afinfo = xfrm_policy_afinfo[AF_INET6];
+        if (afinfo)
+                net->xfrm.xfrm6_dst_ops = *afinfo->dst_ops;
+#endif
+        read_unlock_bh(&xfrm_policy_afinfo_lock);
+}
+
 static struct xfrm_policy_afinfo *xfrm_policy_get_afinfo(unsigned short family)
 {
         struct xfrm_policy_afinfo *afinfo;
@@ -2494,6 +2546,7 @@ static int __net_init xfrm_net_init(struct net *net)
         rv = xfrm_policy_init(net);
         if (rv < 0)
                 goto out_policy;
+        xfrm_dst_ops_init(net);
         rv = xfrm_sysctl_init(net);
         if (rv < 0)
                 goto out_sysctl;