func getEthernet(packet []byte) (*protocol.Ethernet, error) {
eth := new(protocol.Ethernet)
if err := eth.UnmarshalBinary(packet); err != nil {
return nil, err
}
return eth, nil
}
func makeARPReply(request *protocol.ARP, mac net.HardwareAddr) ([]byte, error) {
v := protocol.NewARPReply(mac, request.SHA, request.TPA, request.SPA)
reply, err := v.MarshalBinary()
if err != nil {
return nil, err
}
eth := protocol.Ethernet{
SrcMAC: mac,
DstMAC: request.SHA,
Type: 0x0806,
Payload: reply,
}
return eth.MarshalBinary()
}
func makeARPAnnouncement(ip net.IP, mac net.HardwareAddr) ([]byte, error) {
v := protocol.NewARPRequest(mac, ip, ip)
anon, err := v.MarshalBinary()
if err != nil {
return nil, err
}
eth := protocol.Ethernet{
SrcMAC: mac,
DstMAC: net.HardwareAddr([]byte{0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF}),
Type: 0x0806,
Payload: anon,
}
return eth.MarshalBinary()
}
func (r *L2Switch) processPacket(finder network.Finder, ingress *network.Port, eth *protocol.Ethernet) (drop bool, err error) {
r.log.Debug(fmt.Sprintf("L2Switch: PACKET_IN.. Ingress=%v, SrcMAC=%v, DstMAC=%v", ingress.ID(), eth.SrcMAC, eth.DstMAC))
packet, err := eth.MarshalBinary()
if err != nil {
return false, err
}
// Broadcast?
if isBroadcast(eth) {
r.log.Debug(fmt.Sprintf("L2Switch: broadcasting.. SrcMAC=%v, DstMAC=%v", eth.SrcMAC, eth.DstMAC))
return true, r.stormCtrl.broadcast(ingress, packet)
}
dstNode, err := finder.Node(eth.DstMAC)
if err != nil {
return true, fmt.Errorf("locating a node (MAC=%v): %v", eth.DstMAC, err)
}
// Unknown node?
if dstNode == nil {
r.log.Debug(fmt.Sprintf("L2Switch: unknown node! dropping.. SrcMAC=%v, DstMAC=%v", eth.SrcMAC, eth.DstMAC))
return true, nil
}
// Disconnected node?
port := dstNode.Port().Value()
if port.IsPortDown() || port.IsLinkDown() {
r.log.Debug(fmt.Sprintf("L2Switch: disconnected node! dropping.. SrcMAC=%v, DstMAC=%v", eth.SrcMAC, eth.DstMAC))
return true, nil
}
param := switchParam{}
// Check whether src and dst nodes reside on a same switch device
if ingress.Device().ID() == dstNode.Port().Device().ID() {
param = switchParam{
finder: finder,
ethernet: eth,
ingress: ingress,
egress: dstNode.Port(),
rawPacket: packet,
}
} else {
path := finder.Path(ingress.Device().ID(), dstNode.Port().Device().ID())
if len(path) == 0 {
r.log.Debug(fmt.Sprintf("L2Switch: empty path.. dropping SrcMAC=%v, DstMAC=%v", eth.SrcMAC, eth.DstMAC))
return true, nil
}
egress := path[0][0]
// Drop this packet if it goes back to the ingress port to avoid duplicated packet routing
if ingress.Number() == egress.Number() {
r.log.Debug(fmt.Sprintf("L2Switch: ignore routing path that goes back to the ingress port (SrcMAC=%v, DstMAC=%v)", eth.SrcMAC, eth.DstMAC))
return true, nil
}
param = switchParam{
finder: finder,
ethernet: eth,
ingress: ingress,
egress: egress,
rawPacket: packet,
}
}
return true, r.switching(param)
}