net/ipv6: Add anycast addresses to a global hashtable

icmp6_send() function is expensive on systems with a large number of
interfaces. Every time it’s called, it has to verify that the source
address does not correspond to an existing anycast address by looping
through every device and every anycast address on the device.  This can
result in significant delays for a CPU when there are a large number of
neighbors and ND timers are frequently timing out and calling
neigh_invalidate().

Add anycast addresses to a global hashtable to allow quick searching for
matching anycast addresses.  This is based on inet6_addr_lst in addrconf.c.

Signed-off-by: Jeff Barnhill <0xeffeff@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/include/net/addrconf.h b/include/net/addrconf.h
index 14b789a123e7d9240cea72fc01bf0d4d7acdba9b..1656c59784987bd486ace6be1f10705fb47ac5c6 100644 (file)
--- a/include/net/addrconf.h
+++ b/include/net/addrconf.h
@@ -317,6 +317,8 @@ bool ipv6_chk_acast_addr(struct net *net, struct net_device *dev,
                         const struct in6_addr *addr);
 bool ipv6_chk_acast_addr_src(struct net *net, struct net_device *dev,
                             const struct in6_addr *addr);
+int ipv6_anycast_init(void);
+void ipv6_anycast_cleanup(void);
 
 /* Device notifier */
 int register_inet6addr_notifier(struct notifier_block *nb);

diff --git a/include/net/if_inet6.h b/include/net/if_inet6.h
index d7578cf49c3af85f2cd164a0b242d064b25ed23b..c9c78c15bce04eea71172ecad8693eb363bc2d60 100644 (file)
--- a/include/net/if_inet6.h
+++ b/include/net/if_inet6.h
@@ -146,10 +146,12 @@ struct ifacaddr6 {
        struct in6_addr         aca_addr;
        struct fib6_info        *aca_rt;
        struct ifacaddr6        *aca_next;
+       struct hlist_node       aca_addr_lst;
        int                     aca_users;
        refcount_t              aca_refcnt;
        unsigned long           aca_cstamp;
        unsigned long           aca_tstamp;
+       struct rcu_head         rcu;
 };
 
 #define        IFA_HOST        IPV6_ADDR_LOOPBACK

diff --git a/net/ipv6/af_inet6.c b/net/ipv6/af_inet6.c
index 3f4d61017a6947c9dfb5cd1a38e5a25f1665928f..f0cd291034f0fa8ece55acd0fccf79e02629c98a 100644 (file)
--- a/net/ipv6/af_inet6.c
+++ b/net/ipv6/af_inet6.c
@@ -1001,6 +1001,9 @@ static int __init inet6_init(void)
        err = ip6_flowlabel_init();
        if (err)
                goto ip6_flowlabel_fail;
+       err = ipv6_anycast_init();
+       if (err)
+               goto ipv6_anycast_fail;
        err = addrconf_init();
        if (err)
                goto addrconf_fail;
@@ -1091,6 +1094,8 @@ ipv6_frag_fail:
 ipv6_exthdrs_fail:
        addrconf_cleanup();
 addrconf_fail:
+       ipv6_anycast_cleanup();
+ipv6_anycast_fail:
        ip6_flowlabel_cleanup();
 ip6_flowlabel_fail:
        ndisc_late_cleanup();

diff --git a/net/ipv6/anycast.c b/net/ipv6/anycast.c
index 4e0ff7031edd55ce6dbb3f2c62e22b9040cc7fec..7698637cf827648988d93a2b529810c5ee08109e 100644 (file)
--- a/net/ipv6/anycast.c
+++ b/net/ipv6/anycast.c
@@ -44,8 +44,22 @@
 
 #include <net/checksum.h>
 
+#define IN6_ADDR_HSIZE_SHIFT   8
+#define IN6_ADDR_HSIZE         BIT(IN6_ADDR_HSIZE_SHIFT)
+/*     anycast address hash table
+ */
+static struct hlist_head inet6_acaddr_lst[IN6_ADDR_HSIZE];
+static DEFINE_SPINLOCK(acaddr_hash_lock);
+
 static int ipv6_dev_ac_dec(struct net_device *dev, const struct in6_addr *addr);
 
+static u32 inet6_acaddr_hash(struct net *net, const struct in6_addr *addr)
+{
+       u32 val = ipv6_addr_hash(addr) ^ net_hash_mix(net);
+
+       return hash_32(val, IN6_ADDR_HSIZE_SHIFT);
+}
+
 /*
  *     socket join an anycast group
  */
@@ -204,16 +218,39 @@ void ipv6_sock_ac_close(struct sock *sk)
        rtnl_unlock();
 }
 
+static void ipv6_add_acaddr_hash(struct net *net, struct ifacaddr6 *aca)
+{
+       unsigned int hash = inet6_acaddr_hash(net, &aca->aca_addr);
+
+       spin_lock(&acaddr_hash_lock);
+       hlist_add_head_rcu(&aca->aca_addr_lst, &inet6_acaddr_lst[hash]);
+       spin_unlock(&acaddr_hash_lock);
+}
+
+static void ipv6_del_acaddr_hash(struct ifacaddr6 *aca)
+{
+       spin_lock(&acaddr_hash_lock);
+       hlist_del_init_rcu(&aca->aca_addr_lst);
+       spin_unlock(&acaddr_hash_lock);
+}
+
 static void aca_get(struct ifacaddr6 *aca)
 {
        refcount_inc(&aca->aca_refcnt);
 }
 
+static void aca_free_rcu(struct rcu_head *h)
+{
+       struct ifacaddr6 *aca = container_of(h, struct ifacaddr6, rcu);
+
+       fib6_info_release(aca->aca_rt);
+       kfree(aca);
+}
+
 static void aca_put(struct ifacaddr6 *ac)
 {
        if (refcount_dec_and_test(&ac->aca_refcnt)) {
-               fib6_info_release(ac->aca_rt);
-               kfree(ac);
+               call_rcu(&ac->rcu, aca_free_rcu);
        }
 }
 
@@ -229,6 +266,7 @@ static struct ifacaddr6 *aca_alloc(struct fib6_info *f6i,
        aca->aca_addr = *addr;
        fib6_info_hold(f6i);
        aca->aca_rt = f6i;
+       INIT_HLIST_NODE(&aca->aca_addr_lst);
        aca->aca_users = 1;
        /* aca_tstamp should be updated upon changes */
        aca->aca_cstamp = aca->aca_tstamp = jiffies;
@@ -285,6 +323,8 @@ int __ipv6_dev_ac_inc(struct inet6_dev *idev, const struct in6_addr *addr)
        aca_get(aca);
        write_unlock_bh(&idev->lock);
 
+       ipv6_add_acaddr_hash(net, aca);
+
        ip6_ins_rt(net, f6i);
 
        addrconf_join_solict(idev->dev, &aca->aca_addr);
@@ -325,6 +365,7 @@ int __ipv6_dev_ac_dec(struct inet6_dev *idev, const struct in6_addr *addr)
        else
                idev->ac_list = aca->aca_next;
        write_unlock_bh(&idev->lock);
+       ipv6_del_acaddr_hash(aca);
        addrconf_leave_solict(idev, &aca->aca_addr);
 
        ip6_del_rt(dev_net(idev->dev), aca->aca_rt);
@@ -352,6 +393,8 @@ void ipv6_ac_destroy_dev(struct inet6_dev *idev)
                idev->ac_list = aca->aca_next;
                write_unlock_bh(&idev->lock);
 
+               ipv6_del_acaddr_hash(aca);
+
                addrconf_leave_solict(idev, &aca->aca_addr);
 
                ip6_del_rt(dev_net(idev->dev), aca->aca_rt);
@@ -390,17 +433,25 @@ static bool ipv6_chk_acast_dev(struct net_device *dev, const struct in6_addr *ad
 bool ipv6_chk_acast_addr(struct net *net, struct net_device *dev,
                         const struct in6_addr *addr)
 {
+       unsigned int hash = inet6_acaddr_hash(net, addr);
+       struct net_device *nh_dev;
+       struct ifacaddr6 *aca;
        bool found = false;
 
        rcu_read_lock();
        if (dev)
                found = ipv6_chk_acast_dev(dev, addr);
        else
-               for_each_netdev_rcu(net, dev)
-                       if (ipv6_chk_acast_dev(dev, addr)) {
+               hlist_for_each_entry_rcu(aca, &inet6_acaddr_lst[hash],
+                                        aca_addr_lst) {
+                       nh_dev = fib6_info_nh_dev(aca->aca_rt);
+                       if (!nh_dev || !net_eq(dev_net(nh_dev), net))
+                               continue;
+                       if (ipv6_addr_equal(&aca->aca_addr, addr)) {
                                found = true;
                                break;
                        }
+               }
        rcu_read_unlock();
        return found;
 }
@@ -539,4 +590,25 @@ void ac6_proc_exit(struct net *net)
 {
        remove_proc_entry("anycast6", net->proc_net);
 }
+
+/*     Init / cleanup code
+ */
+int __init ipv6_anycast_init(void)
+{
+       int i;
+
+       for (i = 0; i < IN6_ADDR_HSIZE; i++)
+               INIT_HLIST_HEAD(&inet6_acaddr_lst[i]);
+       return 0;
+}
+
+void ipv6_anycast_cleanup(void)
+{
+       int i;
+
+       spin_lock(&acaddr_hash_lock);
+       for (i = 0; i < IN6_ADDR_HSIZE; i++)
+               WARN_ON(!hlist_empty(&inet6_acaddr_lst[i]));
+       spin_unlock(&acaddr_hash_lock);
+}
 #endif