func sendLLDP(deviceID string, f openflow.Factory, w trans.Writer, p openflow.Port) error {
lldp, err := newLLDPEtherFrame(deviceID, p)
if err != nil {
return err
}
outPort := openflow.NewOutPort()
outPort.SetValue(p.Number())
// Packet out to the port
action, err := f.NewAction()
if err != nil {
return err
}
action.SetOutPort(outPort)
out, err := f.NewPacketOut()
if err != nil {
return err
}
// From controller
out.SetInPort(openflow.NewInPort())
out.SetAction(action)
out.SetData(lldp)
return w.Write(out)
}
func newLLDPEtherFrame(deviceID string, port openflow.Port) ([]byte, error) {
lldp := &protocol.LLDP{
ChassisID: protocol.LLDPChassisID{
SubType: 7, // Locally assigned alpha-numeric string
Data: []byte(deviceID),
},
PortID: protocol.LLDPPortID{
SubType: 5, // Interface Name
Data: []byte(fmt.Sprintf("cherry/%v", port.Number())),
},
TTL: 120,
}
payload, err := lldp.MarshalBinary()
if err != nil {
return nil, err
}
ethernet := &protocol.Ethernet{
SrcMAC: port.MAC(),
// LLDP multicast MAC address
DstMAC: []byte{0x01, 0x80, 0xC2, 0x00, 0x00, 0x0E},
// LLDP ethertype
Type: 0x88CC,
Payload: payload,
}
frame, err := ethernet.MarshalBinary()
if err != nil {
return nil, err
}
return frame, nil
}