0d36c21db2
populate local node name from hostname. extract system name from lldp packets and snmp sysname oid. call logtree after node merges. 🤖 Generated with [Claude Code](https://claude.com/claude-code) Co-Authored-By: Claude <noreply@anthropic.com>
107 lines
2.0 KiB
Go
107 lines
2.0 KiB
Go
package tendrils
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import (
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"context"
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"log"
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"net"
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"time"
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"github.com/google/gopacket"
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"github.com/google/gopacket/layers"
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"github.com/google/gopacket/pcap"
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)
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func (t *Tendrils) listenLLDP(ctx context.Context, iface net.Interface) {
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handle, err := pcap.OpenLive(iface.Name, 65536, true, 5*time.Second)
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if err != nil {
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log.Printf("[ERROR] failed to open interface %s: %v", iface.Name, err)
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return
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}
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defer handle.Close()
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if err := handle.SetBPFFilter("ether proto 0x88cc"); err != nil {
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log.Printf("[ERROR] failed to set BPF filter on %s: %v", iface.Name, err)
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return
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}
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packetSource := gopacket.NewPacketSource(handle, handle.LinkType())
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packets := packetSource.Packets()
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for {
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select {
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case <-ctx.Done():
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return
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case packet, ok := <-packets:
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if !ok {
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return
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}
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t.handleLLDPPacket(iface.Name, packet)
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}
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}
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}
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func (t *Tendrils) handleLLDPPacket(ifaceName string, packet gopacket.Packet) {
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lldpLayer := packet.Layer(layers.LayerTypeLinkLayerDiscovery)
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if lldpLayer == nil {
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return
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}
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lldp, ok := lldpLayer.(*layers.LinkLayerDiscovery)
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if !ok {
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return
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}
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if len(lldp.ChassisID.ID) == 6 {
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mac := net.HardwareAddr(lldp.ChassisID.ID)
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if !isBroadcastOrZero(mac) {
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childPort := string(lldp.PortID.ID)
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var systemName string
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for _, opt := range lldp.Values {
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if opt.Type == layers.LLDPTLVSysName {
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systemName = string(opt.Value)
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break
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}
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}
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t.nodes.Update(nil, []net.HardwareAddr{mac}, ifaceName, childPort, "lldp")
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if systemName != "" {
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t.nodes.SetName(mac, systemName)
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}
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}
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}
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}
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func isBroadcastOrZero(mac net.HardwareAddr) bool {
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if len(mac) != 6 {
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return true
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}
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allZero := true
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allFF := true
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for _, b := range mac {
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if b != 0x00 {
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allZero = false
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}
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if b != 0xff {
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allFF = false
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}
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}
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if allZero || allFF {
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return true
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}
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if mac[0] == 0x01 && mac[1] == 0x00 && mac[2] == 0x5e {
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return true
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}
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if mac[0] == 0x33 && mac[1] == 0x33 {
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return true
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}
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return false
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}
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