On 04/07/2016 03:20 PM, Julian Anastasov wrote:
On Thu, 7 Apr 2016, Chris Friesen wrote:
Hi,
We think we may have found a bug in the handling of ipv4 route caching,
and are curious what you think.
For local routes that require a particular output interface we do not
want to cache the result. Caching the result causes incorrect behaviour
when there are multiple source addresses on the interface. The end
result being that if the intended recipient is waiting on that interface
for the packet he won't receive it because it will be delivered on the
loopback interface and the IP_PKTINFO ipi_ifindex will be set to the
loopback interface as well.
diff --git a/net/ipv4/route.c b/net/ipv4/route.c
index 02c6229..e965d4b 100644
--- a/net/ipv4/route.c
+++ b/net/ipv4/route.c
@@ -2045,6 +2045,17 @@ static struct rtable *__mkroute_output(const struct
fib_result *res,
*/
if (fi && res->prefixlen < 4)
fi = NULL;
+ } else if ((type == RTN_LOCAL) && (orig_oif != 0)) {
So, we can be more specific. Can this work?:
} else if ((type == RTN_LOCAL) && (orig_oif != 0) &&
(orig_oif != dev_out->ifindex)) {
I.e. we should allow to cache orig_oif=LOOPBACK_IFINDEX
but eth1 should not be cached.
Yes, we think that will work. New patch to follow.
Chris
