如何在lldp.go中使用decodeLinkLayerDiscovery

Question

我想解码LLDP数据包中的信息：LLDP.go用decodeLinkLayerDiscovery函数来做，但我不知道如何使用它。例如，我想获得MgmtAddress的值。我该怎么做？

func readLLDP(handle *pcap.Handle, iface *net.Interface, stop chan struct{}) {
src := gopacket.NewPacketSource(handle, layers.LayerTypeEthernet)
in := src.Packets()
p := gopacket.PacketBuilder{}
p.AddLayer()
for {
var packet gopacket.Packet
select {
case <-stop:
return
case packet = <-in:
lldpLayer := packet.Layer(layers.LayerTypeLinkLayerDiscovery)
if lldpLayer == nil {
continue
}
lldp := lldpLayer.(*layers.LinkLayerDiscovery)
var chassisID string
switch lldp.ChassisID.Subtype {
case layers.LLDPChassisIDSubTypeMACAddr:
chassisID = net.HardwareAddr(lldp.ChassisID.ID).String()
default:
chassisID = string(lldp.ChassisID.ID)
}
log.Printf("[%v] ChassisID %v", iface.Name, chassisID)
}
}
}

Answer 1

我找到了解决方案，我必须使用LayerTypeLinkLayerDiscoveryInfo:

lldpLayerInfos := packet.Layer(layers.LayerTypeLinkLayerDiscoveryInfo)
if lldpLayerInfos == nil {
continue
}
lldpInfos := lldpLayerInfos.(*layers.LinkLayerDiscoveryInfo)
log.Printf("[%v] ************************************************", iface.Name)
log.Printf("[%v] PortDescription : %s", iface.Name, lldpInfos.PortDescription)
log.Printf("[%v] SysName : %s", iface.Name, lldpInfos.SysName)
log.Printf("[%v] SysDescription : %s", iface.Name, lldpInfos.SysDescription)
var mgmtAddress string
switch lldpInfos.MgmtAddress.Subtype {
case layers.IANAAddressFamilyIPV4:
mgmtAddress = net.IP(lldpInfos.MgmtAddress.Address).String()
default:
mgmtAddress = string(lldpInfos.MgmtAddress.Address)
}
log.Printf("[%v] MgmtAddress : %s", iface.Name, mgmtAddress)