link: switch to host netns to set up host veth end

diff --git a/ip/link.go b/ip/link.go
index 3936ed9..44e5d84 100644 (file)
--- a/ip/link.go
+++ b/ip/link.go
@@ -20,6 +20,7 @@ import (
        "net"
        "os"
 
+       "github.com/appc/cni/pkg/ns"
        "github.com/vishvananda/netlink"
 )
 
@@ -78,7 +79,8 @@ func RandomVethName() (string, error) {
 }
 
 // SetupVeth sets up a virtual ethernet link.
-// Should be in container netns.
+// Should be in container netns, and will switch back to hostNS to set the host
+// veth end up.
 func SetupVeth(contVethName string, mtu int, hostNS *os.File) (hostVeth, contVeth netlink.Link, err error) {
        var hostVethName string
        hostVethName, contVeth, err = makeVeth(contVethName, mtu)
@@ -97,16 +99,22 @@ 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
        }
 
+       err = ns.WithNetNS(hostNS, false, func(_ *os.File) error {
+               hostVeth, err := netlink.LinkByName(hostVethName)
+               if err != nil {
+                       return fmt.Errorf("failed to lookup %q in %q: %v", hostVethName, hostNS.Name(), err)
+               }
+
+               if err = netlink.LinkSetUp(hostVeth); err != nil {
+                       return fmt.Errorf("failed to set %q up: %v", hostVethName, err)
+               }
+               return nil
+       })
        return
 }