func decodeLLDP(b []byte) (nom.Node, nom.Port, error) {
h := lldp.NewLinkDiscoveryProtocolWithBuf(b)
size := h.Size()
tlvb := b[size:]
chTLV := lldp.NewChassisMacTLVWithBuf(tlvb)
if chTLV.Size() == 0 {
return nom.Node{}, nom.Port{}, errors.New("decodeLLDP: no chassis id")
}
n := nom.Node{
MACAddr: chTLV.MacAddr(),
}
size += chTLV.Size()
tlvb = b[size:]
pTLV := lldp.NewLinkDiscoveryTLVWithBuf(tlvb)
if pTLV.Size() == 0 || pTLV.Type() != uint8(lldp.TLV_PORT_ID) {
return nom.Node{}, nom.Port{}, errors.New("decodeLLDP: no port id")
}
v := pTLV.Value()
if v[0] != uint8(lldp.PORT_TLV_IFACE_NAME) {
return nom.Node{}, nom.Port{}, errors.New("decodeLLDP: no port iface name")
}
portUID := nom.UID(v[1:])
nID, pID := nom.ParsePortUID(portUID)
n.ID = nID
return n, nom.Port{ID: pID, Node: n.UID()}, nil
}
func encodeLLDP(n nom.Node, p nom.Port) []byte {
b := make([]byte, 256)
h := lldp.NewLinkDiscoveryProtocolWithBuf(b)
h.Init()
h.SetSrcMac(n.MACAddr)
h.SetDstMac([6]byte{0x01, 0x80, 0xC2, 0x00, 0x00, 0x0E})
size := h.Size()
tlvb := b[size:]
chTLV := lldp.NewChassisMacTLVWithBuf(tlvb)
chTLV.Init()
chTLV.SetMacAddr(n.MACAddr)
size += chTLV.Size()
tlvb = b[size:]
pTLV := lldp.NewLinkDiscoveryTLVWithBuf(tlvb)
pTLV.Init()
pTLV.SetType(uint8(lldp.TLV_PORT_ID))
pTLV.AddValue(byte(lldp.PORT_TLV_IFACE_NAME))
for _, v := range []byte(p.UID()) {
pTLV.AddValue(v)
}
size += pTLV.Size()
tlvb = b[size:]
ttlTLV := lldp.NewLinkDiscoveryTLVWithBuf(tlvb)
ttlTLV.Init()
ttlTLV.SetType(uint8(lldp.TLV_TTL))
ttlTLV.AddValue(0)
ttlTLV.AddValue(0xFF)
size += ttlTLV.Size()
// TODO(soheil): Maybe add a few custom fields?
return b[:size]
}