ipv4: Add hash table of interface addresses.

This will be used to optimize __ip_dev_find() and friends.

With help from Eric Dumazet.

Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 45 insertions, 0 deletions

diff --git a/net/ipv4/devinet.c b/net/ipv4/devinet.c
index 748cb5b337bd..2fe50765a672 100644
--- a/net/ipv4/devinet.c
+++ b/net/ipv4/devinet.c
@@ -51,6 +51,7 @@
 #include <linux/inetdevice.h>
 #include <linux/igmp.h>
 #include <linux/slab.h>
+#include <linux/hash.h>
 #ifdef CONFIG_SYSCTL
 #include <linux/sysctl.h>
 #endif
@@ -92,6 +93,38 @@ static const struct nla_policy ifa_ipv4_policy[IFA_MAX+1] = {
         [IFA_LABEL]             = { .type = NLA_STRING, .len = IFNAMSIZ - 1 },
 };
 
+/* inet_addr_hash's shifting is dependent upon this IN4_ADDR_HSIZE
+ * value.  So if you change this define, make appropriate changes to
+ * inet_addr_hash as well.
+ */
+#define IN4_ADDR_HSIZE  256
+static struct hlist_head inet_addr_lst[IN4_ADDR_HSIZE];
+static DEFINE_SPINLOCK(inet_addr_hash_lock);
+
+static inline unsigned int inet_addr_hash(struct net *net, __be32 addr)
+{
+        u32 val = (__force u32) addr ^ hash_ptr(net, 8);
+
+        return ((val ^ (val >> 8) ^ (val >> 16) ^ (val >> 24)) &
+                (IN4_ADDR_HSIZE - 1));
+}
+
+static void inet_hash_insert(struct net *net, struct in_ifaddr *ifa)
+{
+        unsigned int hash = inet_addr_hash(net, ifa->ifa_address);
+
+        spin_lock(&inet_addr_hash_lock);
+        hlist_add_head_rcu(&ifa->hash, &inet_addr_lst[hash]);
+        spin_unlock(&inet_addr_hash_lock);
+}
+
+static void inet_hash_remove(struct in_ifaddr *ifa)
+{
+        spin_lock(&inet_addr_hash_lock);
+        hlist_del_init_rcu(&ifa->hash);
+        spin_unlock(&inet_addr_hash_lock);
+}
+
 static void rtmsg_ifa(int event, struct in_ifaddr *, struct nlmsghdr *, u32);
 
 static BLOCKING_NOTIFIER_HEAD(inetaddr_chain);
@@ -265,6 +298,7 @@ static void __inet_del_ifa(struct in_device *in_dev, struct in_ifaddr **ifap,
                         }
 
                         if (!do_promote) {
+                                inet_hash_remove(ifa);
                                 *ifap1 = ifa->ifa_next;
 
                                 rtmsg_ifa(RTM_DELADDR, ifa, nlh, pid);
@@ -281,6 +315,7 @@ static void __inet_del_ifa(struct in_device *in_dev, struct in_ifaddr **ifap,
         /* 2. Unlink it */
 
         *ifap = ifa1->ifa_next;
+        inet_hash_remove(ifa1);
 
         /* 3. Announce address deletion */
 
@@ -368,6 +403,8 @@ static int __inet_insert_ifa(struct in_ifaddr *ifa, struct nlmsghdr *nlh,
         ifa->ifa_next = *ifap;
         *ifap = ifa;
 
+        inet_hash_insert(dev_net(in_dev->dev), ifa);
+
         /* Send message first, then call notifier.
            Notifier will trigger FIB update, so that
            listeners of netlink will know about new ifaddr */
@@ -521,6 +558,7 @@ static struct in_ifaddr *rtm_to_ifaddr(struct net *net, struct nlmsghdr *nlh)
         if (tb[IFA_ADDRESS] == NULL)
                 tb[IFA_ADDRESS] = tb[IFA_LOCAL];
 
+        INIT_HLIST_NODE(&ifa->hash);
         ifa->ifa_prefixlen = ifm->ifa_prefixlen;
         ifa->ifa_mask = inet_make_mask(ifm->ifa_prefixlen);
         ifa->ifa_flags = ifm->ifa_flags;
@@ -728,6 +766,7 @@ int devinet_ioctl(struct net *net, unsigned int cmd, void __user *arg)
                 if (!ifa) {
                         ret = -ENOBUFS;
                         ifa = inet_alloc_ifa();
+                        INIT_HLIST_NODE(&ifa->hash);
                         if (!ifa)
                                 break;
                         if (colon)
@@ -1069,6 +1108,7 @@ static int inetdev_event(struct notifier_block *this, unsigned long event,
                         struct in_ifaddr *ifa = inet_alloc_ifa();
 
                         if (ifa) {
+                                INIT_HLIST_NODE(&ifa->hash);
                                 ifa->ifa_local =
                                   ifa->ifa_address = htonl(INADDR_LOOPBACK);
                                 ifa->ifa_prefixlen = 8;
@@ -1710,6 +1750,11 @@ static struct rtnl_af_ops inet_af_ops = {
 
 void __init devinet_init(void)
 {
+        int i;
+
+        for (i = 0; i < IN4_ADDR_HSIZE; i++)
+                INIT_HLIST_HEAD(&inet_addr_lst[i]);
+
         register_pernet_subsys(&devinet_ops);
 
         register_gifconf(PF_INET, inet_gifconf);