ipv4: introduce __ip_dev_find()
ip_dev_find(net, addr) finds a device given an IPv4 source address and
takes a reference on it.
Introduce __ip_dev_find(), taking a third argument, to optionally take
the device reference. Callers not asking the reference to be taken
should be in an rcu_read_lock() protected section.
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv4/fib_frontend.c b/net/ipv4/fib_frontend.c
index 981f3c5..4a69a95 100644
--- a/net/ipv4/fib_frontend.c
+++ b/net/ipv4/fib_frontend.c
@@ -147,34 +147,40 @@
rt_cache_flush(net, -1);
}
-/*
- * Find the first device with a given source address.
+/**
+ * __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
*/
-
-struct net_device * ip_dev_find(struct net *net, __be32 addr)
+struct net_device *__ip_dev_find(struct net *net, __be32 addr, bool devref)
{
- struct flowi fl = { .nl_u = { .ip4_u = { .daddr = addr } },
- .flags = FLOWI_FLAG_MATCH_ANY_IIF };
- struct fib_result res;
+ struct flowi fl = {
+ .nl_u = {
+ .ip4_u = {
+ .daddr = addr
+ }
+ },
+ .flags = FLOWI_FLAG_MATCH_ANY_IIF
+ };
+ struct fib_result res = { 0 };
struct net_device *dev = NULL;
-#ifdef CONFIG_IP_MULTIPLE_TABLES
- res.r = NULL;
-#endif
-
if (fib_lookup(net, &fl, &res))
return NULL;
if (res.type != RTN_LOCAL)
goto out;
dev = FIB_RES_DEV(res);
- if (dev)
+ if (dev && devref)
dev_hold(dev);
out:
fib_res_put(&res);
return dev;
}
-EXPORT_SYMBOL(ip_dev_find);
+EXPORT_SYMBOL(__ip_dev_find);
/*
* Find address type as if only "dev" was present in the system. If