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| 1 | +package lldp |
| 2 | + |
| 3 | +import ( |
| 4 | + "encoding/binary" |
| 5 | + "fmt" |
| 6 | + "net" |
| 7 | + |
| 8 | + "github.com/google/gopacket/layers" |
| 9 | +) |
| 10 | + |
| 11 | +var ( |
| 12 | + capabilityMap = map[string]uint16{ |
| 13 | + "other": layers.LLDPCapsOther, |
| 14 | + "repeater": layers.LLDPCapsRepeater, |
| 15 | + "bridge": layers.LLDPCapsBridge, |
| 16 | + "wlanap": layers.LLDPCapsWLANAP, |
| 17 | + "router": layers.LLDPCapsRouter, |
| 18 | + "phone": layers.LLDPCapsPhone, |
| 19 | + "docsis": layers.LLDPCapsDocSis, |
| 20 | + "station_only": layers.LLDPCapsStationOnly, |
| 21 | + "cvlan": layers.LLDPCapsCVLAN, |
| 22 | + "svlan": layers.LLDPCapsSVLAN, |
| 23 | + "tmpr": layers.LLDPCapsTmpr, |
| 24 | + } |
| 25 | +) |
| 26 | + |
| 27 | +func tlvMgmtAddressToBytes(m *layers.LLDPMgmtAddress) []byte { |
| 28 | + var b []byte |
| 29 | + b = append(b, byte(len(m.Address))+1) // TLV Length |
| 30 | + b = append(b, byte(m.Subtype)) // Address Subtype |
| 31 | + b = append(b, m.Address...) // Address |
| 32 | + b = append(b, byte(m.InterfaceSubtype)) // Interface Subtype |
| 33 | + |
| 34 | + ifIndex := make([]byte, 4) // 4 bytes for the interface number |
| 35 | + binary.BigEndian.PutUint32(ifIndex, m.InterfaceNumber) |
| 36 | + b = append(b, ifIndex...) |
| 37 | + |
| 38 | + b = append(b, 0) // OID type |
| 39 | + return b |
| 40 | +} |
| 41 | + |
| 42 | +func tlvMgmtAddress(m *layers.LLDPMgmtAddress) layers.LinkLayerDiscoveryValue { |
| 43 | + return layers.LinkLayerDiscoveryValue{ |
| 44 | + Type: layers.LLDPTLVMgmtAddress, |
| 45 | + Value: tlvMgmtAddressToBytes(m), |
| 46 | + Length: uint16(len(tlvMgmtAddressToBytes(m))), |
| 47 | + } |
| 48 | +} |
| 49 | + |
| 50 | +// if err := checkLLDPTLVLen(v, 9); err != nil { |
| 51 | +// return err |
| 52 | +// } |
| 53 | +// mlen := v.Value[0] |
| 54 | +// if err := checkLLDPTLVLen(v, int(mlen+7)); err != nil { |
| 55 | +// return err |
| 56 | +// } |
| 57 | +// info.MgmtAddress.Subtype = IANAAddressFamily(v.Value[1]) |
| 58 | +// info.MgmtAddress.Address = v.Value[2 : mlen+1] |
| 59 | +// info.MgmtAddress.InterfaceSubtype = LLDPInterfaceSubtype(v.Value[mlen+1]) |
| 60 | +// info.MgmtAddress.InterfaceNumber = binary.BigEndian.Uint32(v.Value[mlen+2 : mlen+6]) |
| 61 | +// olen := v.Value[mlen+6] |
| 62 | +// if err := checkLLDPTLVLen(v, int(mlen+7+olen)); err != nil { |
| 63 | +// return err |
| 64 | +// } |
| 65 | +// info.MgmtAddress.OID = string(v.Value[mlen+7 : mlen+7+olen]) |
| 66 | + |
| 67 | +func checkLLDPTLVLen(v layers.LinkLayerDiscoveryValue, l int) (err error) { |
| 68 | + if len(v.Value) < l { |
| 69 | + err = fmt.Errorf("invalid TLV %v length %d (wanted mimimum %v)", v.Type, len(v.Value), l) |
| 70 | + } |
| 71 | + return |
| 72 | +} |
| 73 | + |
| 74 | +// parseTlvMgmtAddress parses the Management Address TLV and returns the Management Address |
| 75 | +// structure. |
| 76 | +// we don't parse the OID here, as it's not needed for the neighbor cache |
| 77 | +func parseTlvMgmtAddress(v layers.LinkLayerDiscoveryValue) *layers.LLDPMgmtAddress { |
| 78 | + if err := checkLLDPTLVLen(v, 9); err != nil { |
| 79 | + return nil |
| 80 | + } |
| 81 | + |
| 82 | + mlen := v.Value[0] |
| 83 | + if err := checkLLDPTLVLen(v, int(mlen+7)); err != nil { |
| 84 | + return nil |
| 85 | + } |
| 86 | + |
| 87 | + return &layers.LLDPMgmtAddress{ |
| 88 | + Subtype: layers.IANAAddressFamily(v.Value[1]), |
| 89 | + Address: v.Value[2 : mlen+1], |
| 90 | + InterfaceSubtype: layers.LLDPInterfaceSubtype(v.Value[mlen+1]), |
| 91 | + InterfaceNumber: binary.BigEndian.Uint32(v.Value[mlen+2 : mlen+6]), |
| 92 | + } |
| 93 | +} |
| 94 | + |
| 95 | +func lldpMgmtAddressToSerializable(m *layers.LLDPMgmtAddress) ManagementAddress { |
| 96 | + var addrString string |
| 97 | + switch m.Subtype { |
| 98 | + case layers.IANAAddressFamilyIPV4: |
| 99 | + addrString = net.IP(m.Address).String() |
| 100 | + case layers.IANAAddressFamilyIPV6: |
| 101 | + addrString = net.IP(m.Address).String() |
| 102 | + default: |
| 103 | + addrString = string(m.Address) |
| 104 | + } |
| 105 | + |
| 106 | + return ManagementAddress{ |
| 107 | + AddressFamily: m.Subtype.String(), |
| 108 | + Address: addrString, |
| 109 | + InterfaceSubtype: m.InterfaceSubtype.String(), |
| 110 | + InterfaceNumber: m.InterfaceNumber, |
| 111 | + } |
| 112 | +} |
| 113 | + |
| 114 | +func tlvStringValue(tlvType layers.LLDPTLVType, value string) layers.LinkLayerDiscoveryValue { |
| 115 | + return layers.LinkLayerDiscoveryValue{ |
| 116 | + Type: tlvType, |
| 117 | + Value: []byte(value), |
| 118 | + Length: uint16(len(value)), |
| 119 | + } |
| 120 | +} |
| 121 | + |
| 122 | +func toLLDPCapabilitiesBytes(capabilities []string) uint16 { |
| 123 | + r := uint16(0) |
| 124 | + for _, capability := range capabilities { |
| 125 | + mask, ok := capabilityMap[capability] |
| 126 | + if ok { |
| 127 | + r |= mask |
| 128 | + } |
| 129 | + } |
| 130 | + return r |
| 131 | +} |
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