netdev-linux: Cache error code from mtu ioctl.

netdev linux devices uses mtu ioctl to get and set MTU for a device.
By caching error code from ioctl we can reduce number of ioctl calls
for device which is unregistered from system.
netdev notification is used to update mtu which saves get-mtu-ioctl.

Signed-off-by: Pravin B Shelar <pshelar@nicira.com>

1 files changed, 1 insertions, 0 deletions

diff --git a/lib/rtnetlink-link.h b/lib/rtnetlink-link.h
index b6ddb214..cfdb24ba 100644
--- a/lib/rtnetlink-link.h
+++ b/lib/rtnetlink-link.h
@@ -37,6 +37,7 @@ struct rtnetlink_link_change {
     /* Extracted from Netlink attributes. */
     const char *ifname;         /* Name of network device. */
     int master_ifindex;         /* Ifindex of datapath master (0 if none). */
+    int mtu;                    /* Current MTU. */
     unsigned int ifi_flags;     /* Flags of network device. */
 };