Add netlink hooks to delete a bridge dev

Signed-off-by: Dhammika Pathirana <dhammika@gmail.com>

Docker-DCO-1.1-Signed-off-by: Dhammika Pathirana <dhammika@gmail.com> (github: dhammika)

netlink/netlink_linux.go

@@ -20,7 +20,9 @@ const (
 	VETH_INFO_PEER = 1
 	IFLA_NET_NS_FD = 28
 	SIOC_BRADDBR   = 0x89a0
+	SIOC_BRDELBR   = 0x89a1
 	SIOC_BRADDIF   = 0x89a2
+	SIOC_BRDELIF   = 0x89a3
 )
 
 var nextSeqNr uint32
@@ -35,6 +37,11 @@ type ifreqIndex struct {
 	IfruIndex int32
 }
 
+type ifreqFlags struct {
+	IfrnName  [IFNAMSIZ]byte
+	Ifruflags uint16
+}
+
 func nativeEndian() binary.ByteOrder {
 	var x uint32 = 0x01020304
 	if *(*byte)(unsafe.Pointer(&x)) == 0x01 {
@@ -921,6 +928,37 @@ func CreateBridge(name string, setMacAddr bool) error {
 	return nil
 }
 
+// Delete the actual bridge device.
+func DeleteBridge(name string) error {
+	s, err := syscall.Socket(syscall.AF_INET6, syscall.SOCK_STREAM, syscall.IPPROTO_IP)
+	if err != nil {
+		// ipv6 issue, creating with ipv4
+		s, err = syscall.Socket(syscall.AF_INET, syscall.SOCK_STREAM, syscall.IPPROTO_IP)
+		if err != nil {
+			return err
+		}
+	}
+	defer syscall.Close(s)
+
+	nameBytePtr, err := syscall.BytePtrFromString(name)
+	if err != nil {
+		return err
+	}
+
+	var ifr ifreqFlags
+	copy(ifr.IfrnName[:], []byte(name))
+	if _, _, err := syscall.Syscall(syscall.SYS_IOCTL, uintptr(s),
+		syscall.SIOCSIFFLAGS, uintptr(unsafe.Pointer(&ifr))); err != 0 {
+		return err
+	}
+
+	if _, _, err := syscall.Syscall(syscall.SYS_IOCTL, uintptr(s),
+		SIOC_BRDELBR, uintptr(unsafe.Pointer(nameBytePtr))); err != 0 {
+		return err
+	}
+	return nil
+}
+
 // Add a slave to abridge device.  This is more backward-compatible than
 // netlink.NetworkSetMaster and works on RHEL 6.
 func AddToBridge(iface, master *net.Interface) error {

netlink/netlink_unsupported.go

@@ -67,6 +67,10 @@ func CreateBridge(name string, setMacAddr bool) error {
 	return ErrNotImplemented
 }
 
+func DeleteBridge(name string) error {
+	return ErrNotImplemented
+}
+
 func AddToBridge(iface, master *net.Interface) error {
 	return ErrNotImplemented
 }