plugins/ptp: allow host veth to be UP

diff --git a/ip/link.go b/ip/link.go
index 3936ed9..e97dcd2 100644 (file)
--- a/ip/link.go
+++ b/ip/link.go
@@ -77,8 +77,9 @@ func RandomVethName() (string, error) {
        return fmt.Sprintf("veth%x", entropy), nil
 }
 
-// SetupVeth sets up a virtual ethernet link.
-// Should be in container netns.
+// SetupVeth creates the virtual ethernet pair and sets up the container's end in the container netns.
+// Setting up the host end up has to be done in the host netns outside of this function.
+// This is because moving the host veth end will cause it to be brought down automatically when it is moved to the host netns.
 func SetupVeth(contVethName string, mtu int, hostNS *os.File) (hostVeth, contVeth netlink.Link, err error) {
        var hostVethName string
        hostVethName, contVeth, err = makeVeth(contVethName, mtu)
@@ -97,11 +98,6 @@ func SetupVeth(contVethName string, mtu int, hostNS *os.File) (hostVeth, contVet
                return
        }
 
-       if err = netlink.LinkSetUp(hostVeth); err != nil {
-               err = fmt.Errorf("failed to set %q up: %v", contVethName, err)
-               return
-       }
-
        if err = netlink.LinkSetNsFd(hostVeth, int(hostNS.Fd())); err != nil {
                err = fmt.Errorf("failed to move veth to host netns: %v", err)
                return