[ovs-dev] [PATCH 2/3] netdev-linux: make tap devices persistent.

[Vishal Deep Ajmera]

Hi Flavio,

If the tap-device is persistent but the 'netdev' datapath is not yet started then will it create any issues in the system ? What happens if we start sending packets on this interface whereas data-path is not present ?

Regards,
Vishal

-----Original Message-----
From: ovs-dev-bounces at openvswitch.org [mailto:ovs-dev-bounces at openvswitch.org] On Behalf Of Flavio Leitner
Sent: Tuesday, May 30, 2017 1:10 AM
To: dev at openvswitch.org
Cc: Flavio Leitner <fbl at redhat.com>
Subject: [ovs-dev] [PATCH 2/3] netdev-linux: make tap devices persistent.

When using data path type "netdev", bridge port is a tun device and when OVS restarts, that device and its network configuration is lost.

This patch enables the tap device to persist instead.

Signed-off-by: Flavio Leitner <fbl at redhat.com>
---
 lib/netdev-linux.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/lib/netdev-linux.c b/lib/netdev-linux.c index 3ad3d45..d181e4f 100644
--- a/lib/netdev-linux.c
+++ b/lib/netdev-linux.c
@@ -866,6 +866,13 @@ netdev_linux_construct_tap(struct netdev *netdev_)
         goto error_close;
     }
 
+    if (ioctl(netdev->tap_fd, TUNSETPERSIST, 1)) {
+        VLOG_WARN("%s: creating tap device failed (persist): %s", name,
+                  ovs_strerror(errno));
+        error = errno;
+        goto error_close;
+    }
+
     return 0;
 
 error_close:
@@ -885,6 +892,7 @@ netdev_linux_destruct(struct netdev *netdev_)
     if (netdev_get_class(netdev_) == &netdev_tap_class
         && netdev->tap_fd >= 0)
     {
+        ioctl(netdev->tap_fd, TUNSETPERSIST, 0);
         close(netdev->tap_fd);
     }
 
--
2.9.4

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