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>

3 files changed, 78 insertions, 20 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);
diff --git a/net/ipv6/xfrm6_policy.c b/net/ipv6/xfrm6_policy.c
index 7254e3f899a7..dbdc696f5fc5 100644
--- a/net/ipv6/xfrm6_policy.c
+++ b/net/ipv6/xfrm6_policy.c
@@ -24,7 +24,6 @@
 #include <net/mip6.h>
 #endif
 
-static struct dst_ops xfrm6_dst_ops;
 static struct xfrm_policy_afinfo xfrm6_policy_afinfo;
 
 static struct dst_entry *xfrm6_dst_lookup(struct net *net, int tos,
@@ -224,8 +223,10 @@ _decode_session6(struct sk_buff *skb, struct flowi *fl, int reverse)
 
 static inline int xfrm6_garbage_collect(struct dst_ops *ops)
 {
-        xfrm6_policy_afinfo.garbage_collect(&init_net);
-        return (atomic_read(&xfrm6_dst_ops.entries) > xfrm6_dst_ops.gc_thresh*2);
+        struct net *net = container_of(ops, struct net, xfrm.xfrm6_dst_ops);
+
+        xfrm6_policy_afinfo.garbage_collect(net);
+        return (atomic_read(&ops->entries) > ops->gc_thresh * 2);
 }
 
 static void xfrm6_update_pmtu(struct dst_entry *dst, u32 mtu)
@@ -310,7 +311,7 @@ static void xfrm6_policy_fini(void)
 static struct ctl_table xfrm6_policy_table[] = {
         {
                 .procname       = "xfrm6_gc_thresh",
-                .data           = &xfrm6_dst_ops.gc_thresh,
+                .data           = &init_net.xfrm.xfrm6_dst_ops.gc_thresh,
                 .maxlen         = sizeof(int),
                 .mode           = 0644,
                 .proc_handler   = proc_dointvec,
@@ -326,13 +327,6 @@ int __init xfrm6_init(void)
         int ret;
         unsigned int gc_thresh;
 
-        ret = xfrm6_policy_init();
-        if (ret)
-                goto out;
-
-        ret = xfrm6_state_init();
-        if (ret)
-                goto out_policy;
         /*
          * We need a good default value for the xfrm6 gc threshold.
          * In ipv4 we set it to the route hash table size * 8, which
@@ -346,6 +340,15 @@ int __init xfrm6_init(void)
          */
         gc_thresh = FIB6_TABLE_HASHSZ * 8;
         xfrm6_dst_ops.gc_thresh = (gc_thresh < 1024) ? 1024 : gc_thresh;
+
+        ret = xfrm6_policy_init();
+        if (ret)
+                goto out;
+
+        ret = xfrm6_state_init();
+        if (ret)
+                goto out_policy;
+
 #ifdef CONFIG_SYSCTL
         sysctl_hdr = register_net_sysctl_table(&init_net, net_ipv6_ctl_path,
                                                 xfrm6_policy_table);
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;