netns xfrm: xfrm6_tunnel in netns

I'm not sure about rcu stuff near kmem cache destruction:
* checks for non-empty hashes look bogus, they're done _before_
  rcu_berrier()
* unregistering netns ops is done before kmem_cache destoy
  (as it should), and unregistering involves rcu barriers by itself

So it looks nothing should be done.

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

3 files changed, 88 insertions, 62 deletions

diff --git a/include/net/xfrm.h b/include/net/xfrm.h
index 60c27706e7b9..fcee547ca7e3 100644
--- a/include/net/xfrm.h
+++ b/include/net/xfrm.h
@@ -1408,9 +1408,9 @@ extern int xfrm6_input_addr(struct sk_buff *skb, xfrm_address_t *daddr,
                             xfrm_address_t *saddr, u8 proto);
 extern int xfrm6_tunnel_register(struct xfrm6_tunnel *handler, unsigned short family);
 extern int xfrm6_tunnel_deregister(struct xfrm6_tunnel *handler, unsigned short family);
-extern __be32 xfrm6_tunnel_alloc_spi(xfrm_address_t *saddr);
-extern void xfrm6_tunnel_free_spi(xfrm_address_t *saddr);
-extern __be32 xfrm6_tunnel_spi_lookup(xfrm_address_t *saddr);
+extern __be32 xfrm6_tunnel_alloc_spi(struct net *net, xfrm_address_t *saddr);
+extern void xfrm6_tunnel_free_spi(struct net *net, xfrm_address_t *saddr);
+extern __be32 xfrm6_tunnel_spi_lookup(struct net *net, xfrm_address_t *saddr);
 extern int xfrm6_extract_output(struct xfrm_state *x, struct sk_buff *skb);
 extern int xfrm6_prepare_output(struct xfrm_state *x, struct sk_buff *skb);
 extern int xfrm6_output(struct sk_buff *skb);
diff --git a/net/ipv6/ipcomp6.c b/net/ipv6/ipcomp6.c
index 2f2a5ca2c878..1d1faf757c9a 100644
--- a/net/ipv6/ipcomp6.c
+++ b/net/ipv6/ipcomp6.c
@@ -81,7 +81,7 @@ static struct xfrm_state *ipcomp6_tunnel_create(struct xfrm_state *x)
                 goto out;
 
         t->id.proto = IPPROTO_IPV6;
-        t->id.spi = xfrm6_tunnel_alloc_spi((xfrm_address_t *)&x->props.saddr);
+        t->id.spi = xfrm6_tunnel_alloc_spi(&init_net, (xfrm_address_t *)&x->props.saddr);
         if (!t->id.spi)
                 goto error;
 
@@ -112,7 +112,7 @@ static int ipcomp6_tunnel_attach(struct xfrm_state *x)
         struct xfrm_state *t = NULL;
         __be32 spi;
 
-        spi = xfrm6_tunnel_spi_lookup((xfrm_address_t *)&x->props.saddr);
+        spi = xfrm6_tunnel_spi_lookup(&init_net, (xfrm_address_t *)&x->props.saddr);
         if (spi)
                 t = xfrm_state_lookup(&init_net, (xfrm_address_t *)&x->id.daddr,
                                               spi, IPPROTO_IPV6, AF_INET6);
diff --git a/net/ipv6/xfrm6_tunnel.c b/net/ipv6/xfrm6_tunnel.c
index 23fb1002124c..d6f9aeec69f7 100644
--- a/net/ipv6/xfrm6_tunnel.c
+++ b/net/ipv6/xfrm6_tunnel.c
@@ -30,6 +30,25 @@
 #include <linux/ipv6.h>
 #include <linux/icmpv6.h>
 #include <linux/mutex.h>
+#include <net/netns/generic.h>
+
+#define XFRM6_TUNNEL_SPI_BYADDR_HSIZE 256
+#define XFRM6_TUNNEL_SPI_BYSPI_HSIZE 256
+
+#define XFRM6_TUNNEL_SPI_MIN    1
+#define XFRM6_TUNNEL_SPI_MAX    0xffffffff
+
+struct xfrm6_tunnel_net {
+        struct hlist_head spi_byaddr[XFRM6_TUNNEL_SPI_BYADDR_HSIZE];
+        struct hlist_head spi_byspi[XFRM6_TUNNEL_SPI_BYSPI_HSIZE];
+        u32 spi;
+};
+
+static int xfrm6_tunnel_net_id __read_mostly;
+static inline struct xfrm6_tunnel_net *xfrm6_tunnel_pernet(struct net *net)
+{
+        return net_generic(net, xfrm6_tunnel_net_id);
+}
 
 /*
  * xfrm_tunnel_spi things are for allocating unique id ("spi")
@@ -46,19 +65,8 @@ struct xfrm6_tunnel_spi {
 
 static DEFINE_SPINLOCK(xfrm6_tunnel_spi_lock);
 
-static u32 xfrm6_tunnel_spi;
-
-#define XFRM6_TUNNEL_SPI_MIN    1
-#define XFRM6_TUNNEL_SPI_MAX    0xffffffff
-
 static struct kmem_cache *xfrm6_tunnel_spi_kmem __read_mostly;
 
-#define XFRM6_TUNNEL_SPI_BYADDR_HSIZE 256
-#define XFRM6_TUNNEL_SPI_BYSPI_HSIZE 256
-
-static struct hlist_head xfrm6_tunnel_spi_byaddr[XFRM6_TUNNEL_SPI_BYADDR_HSIZE];
-static struct hlist_head xfrm6_tunnel_spi_byspi[XFRM6_TUNNEL_SPI_BYSPI_HSIZE];
-
 static inline unsigned xfrm6_tunnel_spi_hash_byaddr(xfrm_address_t *addr)
 {
         unsigned h;
@@ -77,49 +85,30 @@ static inline unsigned xfrm6_tunnel_spi_hash_byspi(u32 spi)
 }
 
 
-static int xfrm6_tunnel_spi_init(void)
+static int __init xfrm6_tunnel_spi_init(void)
 {
-        int i;
-
-        xfrm6_tunnel_spi = 0;
         xfrm6_tunnel_spi_kmem = kmem_cache_create("xfrm6_tunnel_spi",
                                                   sizeof(struct xfrm6_tunnel_spi),
                                                   0, SLAB_HWCACHE_ALIGN,
                                                   NULL);
         if (!xfrm6_tunnel_spi_kmem)
                 return -ENOMEM;
-
-        for (i = 0; i < XFRM6_TUNNEL_SPI_BYADDR_HSIZE; i++)
-                INIT_HLIST_HEAD(&xfrm6_tunnel_spi_byaddr[i]);
-        for (i = 0; i < XFRM6_TUNNEL_SPI_BYSPI_HSIZE; i++)
-                INIT_HLIST_HEAD(&xfrm6_tunnel_spi_byspi[i]);
         return 0;
 }
 
 static void xfrm6_tunnel_spi_fini(void)
 {
-        int i;
-
-        for (i = 0; i < XFRM6_TUNNEL_SPI_BYADDR_HSIZE; i++) {
-                if (!hlist_empty(&xfrm6_tunnel_spi_byaddr[i]))
-                        return;
-        }
-        for (i = 0; i < XFRM6_TUNNEL_SPI_BYSPI_HSIZE; i++) {
-                if (!hlist_empty(&xfrm6_tunnel_spi_byspi[i]))
-                        return;
-        }
-        rcu_barrier();
         kmem_cache_destroy(xfrm6_tunnel_spi_kmem);
-        xfrm6_tunnel_spi_kmem = NULL;
 }
 
-static struct xfrm6_tunnel_spi *__xfrm6_tunnel_spi_lookup(xfrm_address_t *saddr)
+static struct xfrm6_tunnel_spi *__xfrm6_tunnel_spi_lookup(struct net *net, xfrm_address_t *saddr)
 {
+        struct xfrm6_tunnel_net *xfrm6_tn = xfrm6_tunnel_pernet(net);
         struct xfrm6_tunnel_spi *x6spi;
         struct hlist_node *pos;
 
         hlist_for_each_entry_rcu(x6spi, pos,
-                             &xfrm6_tunnel_spi_byaddr[xfrm6_tunnel_spi_hash_byaddr(saddr)],
+                             &xfrm6_tn->spi_byaddr[xfrm6_tunnel_spi_hash_byaddr(saddr)],
                              list_byaddr) {
                 if (memcmp(&x6spi->addr, saddr, sizeof(x6spi->addr)) == 0)
                         return x6spi;
@@ -128,13 +117,13 @@ static struct xfrm6_tunnel_spi *__xfrm6_tunnel_spi_lookup(xfrm_address_t *saddr)
         return NULL;
 }
 
-__be32 xfrm6_tunnel_spi_lookup(xfrm_address_t *saddr)
+__be32 xfrm6_tunnel_spi_lookup(struct net *net, xfrm_address_t *saddr)
 {
         struct xfrm6_tunnel_spi *x6spi;
         u32 spi;
 
         rcu_read_lock_bh();
-        x6spi = __xfrm6_tunnel_spi_lookup(saddr);
+        x6spi = __xfrm6_tunnel_spi_lookup(net, saddr);
         spi = x6spi ? x6spi->spi : 0;
         rcu_read_unlock_bh();
         return htonl(spi);
@@ -142,14 +131,15 @@ __be32 xfrm6_tunnel_spi_lookup(xfrm_address_t *saddr)
 
 EXPORT_SYMBOL(xfrm6_tunnel_spi_lookup);
 
-static int __xfrm6_tunnel_spi_check(u32 spi)
+static int __xfrm6_tunnel_spi_check(struct net *net, u32 spi)
 {
+        struct xfrm6_tunnel_net *xfrm6_tn = xfrm6_tunnel_pernet(net);
         struct xfrm6_tunnel_spi *x6spi;
         int index = xfrm6_tunnel_spi_hash_byspi(spi);
         struct hlist_node *pos;
 
         hlist_for_each_entry(x6spi, pos,
-                             &xfrm6_tunnel_spi_byspi[index],
+                             &xfrm6_tn->spi_byspi[index],
                              list_byspi) {
                 if (x6spi->spi == spi)
                         return -1;
@@ -157,32 +147,33 @@ static int __xfrm6_tunnel_spi_check(u32 spi)
         return index;
 }
 
-static u32 __xfrm6_tunnel_alloc_spi(xfrm_address_t *saddr)
+static u32 __xfrm6_tunnel_alloc_spi(struct net *net, xfrm_address_t *saddr)
 {
+        struct xfrm6_tunnel_net *xfrm6_tn = xfrm6_tunnel_pernet(net);
         u32 spi;
         struct xfrm6_tunnel_spi *x6spi;
         int index;
 
-        if (xfrm6_tunnel_spi < XFRM6_TUNNEL_SPI_MIN ||
-            xfrm6_tunnel_spi >= XFRM6_TUNNEL_SPI_MAX)
-                xfrm6_tunnel_spi = XFRM6_TUNNEL_SPI_MIN;
+        if (xfrm6_tn->spi < XFRM6_TUNNEL_SPI_MIN ||
+            xfrm6_tn->spi >= XFRM6_TUNNEL_SPI_MAX)
+                xfrm6_tn->spi = XFRM6_TUNNEL_SPI_MIN;
         else
-                xfrm6_tunnel_spi++;
+                xfrm6_tn->spi++;
 
-        for (spi = xfrm6_tunnel_spi; spi <= XFRM6_TUNNEL_SPI_MAX; spi++) {
-                index = __xfrm6_tunnel_spi_check(spi);
+        for (spi = xfrm6_tn->spi; spi <= XFRM6_TUNNEL_SPI_MAX; spi++) {
+                index = __xfrm6_tunnel_spi_check(net, spi);
                 if (index >= 0)
                         goto alloc_spi;
         }
-        for (spi = XFRM6_TUNNEL_SPI_MIN; spi < xfrm6_tunnel_spi; spi++) {
-                index = __xfrm6_tunnel_spi_check(spi);
+        for (spi = XFRM6_TUNNEL_SPI_MIN; spi < xfrm6_tn->spi; spi++) {
+                index = __xfrm6_tunnel_spi_check(net, spi);
                 if (index >= 0)
                         goto alloc_spi;
         }
         spi = 0;
         goto out;
 alloc_spi:
-        xfrm6_tunnel_spi = spi;
+        xfrm6_tn->spi = spi;
         x6spi = kmem_cache_alloc(xfrm6_tunnel_spi_kmem, GFP_ATOMIC);
         if (!x6spi)
                 goto out;
@@ -192,26 +183,26 @@ alloc_spi:
         x6spi->spi = spi;
         atomic_set(&x6spi->refcnt, 1);
 
-        hlist_add_head_rcu(&x6spi->list_byspi, &xfrm6_tunnel_spi_byspi[index]);
+        hlist_add_head_rcu(&x6spi->list_byspi, &xfrm6_tn->spi_byspi[index]);
 
         index = xfrm6_tunnel_spi_hash_byaddr(saddr);
-        hlist_add_head_rcu(&x6spi->list_byaddr, &xfrm6_tunnel_spi_byaddr[index]);
+        hlist_add_head_rcu(&x6spi->list_byaddr, &xfrm6_tn->spi_byaddr[index]);
 out:
         return spi;
 }
 
-__be32 xfrm6_tunnel_alloc_spi(xfrm_address_t *saddr)
+__be32 xfrm6_tunnel_alloc_spi(struct net *net, xfrm_address_t *saddr)
 {
         struct xfrm6_tunnel_spi *x6spi;
         u32 spi;
 
         spin_lock_bh(&xfrm6_tunnel_spi_lock);
-        x6spi = __xfrm6_tunnel_spi_lookup(saddr);
+        x6spi = __xfrm6_tunnel_spi_lookup(net, saddr);
         if (x6spi) {
                 atomic_inc(&x6spi->refcnt);
                 spi = x6spi->spi;
         } else
-                spi = __xfrm6_tunnel_alloc_spi(saddr);
+                spi = __xfrm6_tunnel_alloc_spi(net, saddr);
         spin_unlock_bh(&xfrm6_tunnel_spi_lock);
 
         return htonl(spi);
@@ -225,15 +216,16 @@ static void x6spi_destroy_rcu(struct rcu_head *head)
                         container_of(head, struct xfrm6_tunnel_spi, rcu_head));
 }
 
-void xfrm6_tunnel_free_spi(xfrm_address_t *saddr)
+void xfrm6_tunnel_free_spi(struct net *net, xfrm_address_t *saddr)
 {
+        struct xfrm6_tunnel_net *xfrm6_tn = xfrm6_tunnel_pernet(net);
         struct xfrm6_tunnel_spi *x6spi;
         struct hlist_node *pos, *n;
 
         spin_lock_bh(&xfrm6_tunnel_spi_lock);
 
         hlist_for_each_entry_safe(x6spi, pos, n,
-                                  &xfrm6_tunnel_spi_byaddr[xfrm6_tunnel_spi_hash_byaddr(saddr)],
+                                  &xfrm6_tn->spi_byaddr[xfrm6_tunnel_spi_hash_byaddr(saddr)],
                                   list_byaddr)
         {
                 if (memcmp(&x6spi->addr, saddr, sizeof(x6spi->addr)) == 0) {
@@ -263,10 +255,11 @@ static int xfrm6_tunnel_input(struct xfrm_state *x, struct sk_buff *skb)
 
 static int xfrm6_tunnel_rcv(struct sk_buff *skb)
 {
+        struct net *net = dev_net(skb->dev);
         struct ipv6hdr *iph = ipv6_hdr(skb);
         __be32 spi;
 
-        spi = xfrm6_tunnel_spi_lookup((xfrm_address_t *)&iph->saddr);
+        spi = xfrm6_tunnel_spi_lookup(net, (xfrm_address_t *)&iph->saddr);
         return xfrm6_rcv_spi(skb, IPPROTO_IPV6, spi) > 0 ? : 0;
 }
 
@@ -326,7 +319,9 @@ static int xfrm6_tunnel_init_state(struct xfrm_state *x)
 
 static void xfrm6_tunnel_destroy(struct xfrm_state *x)
 {
-        xfrm6_tunnel_free_spi((xfrm_address_t *)&x->props.saddr);
+        struct net *net = xs_net(x);
+
+        xfrm6_tunnel_free_spi(net, (xfrm_address_t *)&x->props.saddr);
 }
 
 static const struct xfrm_type xfrm6_tunnel_type = {
@@ -351,6 +346,31 @@ static struct xfrm6_tunnel xfrm46_tunnel_handler = {
         .priority       = 2,
 };
 
+static int __net_init xfrm6_tunnel_net_init(struct net *net)
+{
+        struct xfrm6_tunnel_net *xfrm6_tn = xfrm6_tunnel_pernet(net);
+        unsigned int i;
+
+        for (i = 0; i < XFRM6_TUNNEL_SPI_BYADDR_HSIZE; i++)
+                INIT_HLIST_HEAD(&xfrm6_tn->spi_byaddr[i]);
+        for (i = 0; i < XFRM6_TUNNEL_SPI_BYSPI_HSIZE; i++)
+                INIT_HLIST_HEAD(&xfrm6_tn->spi_byspi[i]);
+        xfrm6_tn->spi = 0;
+
+        return 0;
+}
+
+static void __net_exit xfrm6_tunnel_net_exit(struct net *net)
+{
+}
+
+static struct pernet_operations xfrm6_tunnel_net_ops = {
+        .init   = xfrm6_tunnel_net_init,
+        .exit   = xfrm6_tunnel_net_exit,
+        .id     = &xfrm6_tunnel_net_id,
+        .size   = sizeof(struct xfrm6_tunnel_net),
+};
+
 static int __init xfrm6_tunnel_init(void)
 {
         int rv;
@@ -367,8 +387,13 @@ static int __init xfrm6_tunnel_init(void)
         rv = xfrm6_tunnel_spi_init();
         if (rv < 0)
                 goto dereg46;
+        rv = register_pernet_subsys(&xfrm6_tunnel_net_ops);
+        if (rv < 0)
+                goto deregspi;
         return 0;
 
+deregspi:
+        xfrm6_tunnel_spi_fini();
 dereg46:
         xfrm6_tunnel_deregister(&xfrm46_tunnel_handler, AF_INET);
 dereg6:
@@ -381,6 +406,7 @@ err:
 
 static void __exit xfrm6_tunnel_fini(void)
 {
+        unregister_pernet_subsys(&xfrm6_tunnel_net_ops);
         xfrm6_tunnel_spi_fini();
         xfrm6_tunnel_deregister(&xfrm46_tunnel_handler, AF_INET);
         xfrm6_tunnel_deregister(&xfrm6_tunnel_handler, AF_INET6);