Commit fc75fc83 authored Dec 22, 2010 by Eric Dumazet Committed by David S. Miller Dec 25, 2010

ipv4: dont create routes on down devices



In ip_route_output_slow(), instead of allowing a route to be created on
a not UPed device, report -ENETUNREACH immediately.

# ip tunnel add mode ipip remote 10.16.0.164 local
10.16.0.72 dev eth0
# (Note : tunl1 is down)
# ping -I tunl1 10.1.2.3
PING 10.1.2.3 (10.1.2.3) from 192.168.18.5 tunl1: 56(84) bytes of data.
(nothing)
# ./a.out tunl1
# ip tunnel del tunl1
Message from syslogd@shelby at Dec 22 10:12:08 ...
  kernel: unregister_netdevice: waiting for tunl1 to become free.
Usage count = 3

After patch:
# ping -I tunl1 10.1.2.3
connect: Network is unreachable

Reported-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Reviewed-by: Octavian Purdila <opurdila@ixiacom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

parent 7a36df8a

net/ipv4/route.c

+4 −3

Original line number	Diff line number	Diff line
		@@ -2585,9 +2585,10 @@ static int ip_route_output_slow(struct net net, struct rtable *rp,
		goto out;

		/* RACE: Check return value of inet_select_addr instead. */
		if (rcu_dereference(dev_out->ip_ptr) == NULL)
		goto out; /* Wrong error code */

		if (!(dev_out->flags & IFF_UP) \|\| !__in_dev_get_rcu(dev_out)) {
		err = -ENETUNREACH;
		goto out;
		}
		if (ipv4_is_local_multicast(oldflp->fl4_dst) \|\|
		ipv4_is_lbcast(oldflp->fl4_dst)) {
		if (!fl.fl4_src)

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