ipv4: Implement __ip_dev_find using new interface address hash.

Much quicker than going through the FIB tables.

Signed-off-by: David S. Miller <[e-mail]>

net/ipv4/devinet.c

···
 	spin_unlock(&inet_addr_hash_lock);
 }
 
+/**
+ * __ip_dev_find - find the first device with a given source address.
+ * @net: the net namespace
+ * @addr: the source address
+ * @devref: if true, take a reference on the found device
+ *
+ * If a caller uses devref=false, it should be protected by RCU, or RTNL
+ */
+struct net_device *__ip_dev_find(struct net *net, __be32 addr, bool devref)
+{
+	unsigned int hash = inet_addr_hash(net, addr);
+	struct net_device *result = NULL;
+	struct in_ifaddr *ifa;
+	struct hlist_node *node;
+
+	rcu_read_lock();
+	hlist_for_each_entry_rcu(ifa, node, &inet_addr_lst[hash], hash) {
+		struct net_device *dev = ifa->ifa_dev->dev;
+
+		if (!net_eq(dev_net(dev), net))
+			continue;
+		if (ifa->ifa_address == addr) {
+			result = dev;
+			break;
+		}
+	}
+	if (result && devref)
+		dev_hold(result);
+	rcu_read_unlock();
+	return result;
+}
+EXPORT_SYMBOL(__ip_dev_find);
+
 static void rtmsg_ifa(int event, struct in_ifaddr *, struct nlmsghdr *, u32);
 
 static BLOCKING_NOTIFIER_HEAD(inetaddr_chain);

net/ipv4/fib_frontend.c

···
 		rt_cache_flush(net, -1);
 }
 
-/**
- * __ip_dev_find - find the first device with a given source address.
- * @net: the net namespace
- * @addr: the source address
- * @devref: if true, take a reference on the found device
- *
- * If a caller uses devref=false, it should be protected by RCU, or RTNL
- */
-struct net_device *__ip_dev_find(struct net *net, __be32 addr, bool devref)
-{
-	struct flowi fl = {
-		.fl4_dst = addr,
-	};
-	struct fib_result res = { 0 };
-	struct net_device *dev = NULL;
-	struct fib_table *local_table;
-
-#ifdef CONFIG_IP_MULTIPLE_TABLES
-	res.r = NULL;
-#endif
-
-	rcu_read_lock();
-	local_table = fib_get_table(net, RT_TABLE_LOCAL);
-	if (!local_table ||
-	    fib_table_lookup(local_table, &fl, &res, FIB_LOOKUP_NOREF)) {
-		rcu_read_unlock();
-		return NULL;
-	}
-	if (res.type != RTN_LOCAL)
-		goto out;
-	dev = FIB_RES_DEV(res);
-
-	if (dev && devref)
-		dev_hold(dev);
-out:
-	rcu_read_unlock();
-	return dev;
-}
-EXPORT_SYMBOL(__ip_dev_find);
-
 /*
  * Find address type as if only "dev" was present in the system. If
  * on_dev is NULL then all interfaces are taken into consideration.