201 lines
4.7 KiB
Go
201 lines
4.7 KiB
Go
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package snmp
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import (
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"bytes"
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"encoding/binary"
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"git.loafle.net/overflow/commons_go/matcher/packet"
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"git.loafle.net/overflow/commons_go/model/scaninfo"
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)
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const (
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SNMP_START_SEQUENCE uint8 = 0X30
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SNMP_TYPE_INTEGER uint8 = 0X02
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SNMP_TYPE_STRING uint8 = 0X04
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SNMP_TYPE_NULL uint8 = 0X05
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SNMP_TYPE_OBJECT uint8 = 0X06
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SNMP_GET_REQUEST uint8 = 0XA0
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//SNMP_RESPONSE uint8 = 0XA2
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SNMP_NO_DESC uint16 = 0X0004
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SNMP_END_SEQUENCE uint8 = 0X30
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SNMP_PROTOCOL_VERSION_3 uint8 = 0X03
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SNMP_PROTOCOL_VERSION_2c uint8 = 0X01
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SNMP_MSG_ID_MAX_VALUE uint32 = 0xFFFFFF7F
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)
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type snmpv2VarBinding struct {
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VarBindindStart uint8
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VarBindLen uint8
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ObjectStart uint8
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ObjectLen uint8
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ValueType uint8
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ValueLen uint8
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ObjectValue uint64
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NullValue uint8
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EndIndicator uint8
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}
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type snmpv2Data struct {
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DataType uint8
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DataLen uint8
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RequestIdType uint8
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RequestIdLen uint8
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RequestId uint8
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ErrorStatusType uint8
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ErrorStatusLen uint8
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ErrorStatus uint8
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ErrorIndexType uint8
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ErrorIndexLen uint8
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ErrorIndex uint8
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VarBinding snmpv2VarBinding
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}
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type snmpv2 struct {
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StartSeq uint8
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SeqLen uint8
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SNMPVersionType uint8
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SNMPVersionLen uint8
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SNMPVersion uint8
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CommunityVersionType uint8
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CommunityVersionLen uint8
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Community [6]byte
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Data snmpv2Data
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}
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type SNMPv2Matcher struct {
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packets []*packet.Packet
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}
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func NewSNMPv2Matcher() *SNMPv2Matcher {
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snmpMatcher := &SNMPv2Matcher{}
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snmpTempBuf := new(bytes.Buffer)
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binary.Write(snmpTempBuf, binary.BigEndian, snmpv2{}) //For getting the struct size
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snmpDataTempBuf := new(bytes.Buffer)
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binary.Write(snmpDataTempBuf, binary.BigEndian, snmpv2Data{}) //For getting the struct size
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snmpVarTempBuf := new(bytes.Buffer)
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binary.Write(snmpVarTempBuf, binary.BigEndian, snmpv2VarBinding{}) //For getting the struct size
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q := snmpv2{}
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q.StartSeq = SNMP_START_SEQUENCE
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q.SeqLen = uint8(len(snmpTempBuf.Bytes())) - 2
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q.SNMPVersionType = SNMP_TYPE_INTEGER
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q.SNMPVersionLen = 0x01
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q.SNMPVersion = SNMP_PROTOCOL_VERSION_2c
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q.CommunityVersionType = SNMP_TYPE_STRING
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q.CommunityVersionLen = 0x06
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var community [6]byte
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copy(community[:], "public")
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q.Community = community
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q.Data.DataType = SNMP_GET_REQUEST
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q.Data.DataLen = uint8(len(snmpDataTempBuf.Bytes())) - 2
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q.Data.RequestIdType = SNMP_TYPE_INTEGER
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q.Data.RequestIdLen = 0x01
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q.Data.RequestId = 0x01
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q.Data.ErrorStatusType = SNMP_TYPE_INTEGER
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q.Data.ErrorStatusLen = 0x01
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q.Data.ErrorStatus = 0x00
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q.Data.ErrorIndexType = SNMP_TYPE_INTEGER
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q.Data.ErrorIndexLen = 0x01
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q.Data.ErrorIndex = 0x00
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q.Data.VarBinding.VarBindindStart = SNMP_START_SEQUENCE
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q.Data.VarBinding.VarBindLen = uint8(len(snmpVarTempBuf.Bytes())) - 2
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q.Data.VarBinding.ObjectStart = SNMP_START_SEQUENCE
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q.Data.VarBinding.ObjectLen = uint8(len(snmpVarTempBuf.Bytes())) - 4
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q.Data.VarBinding.ValueType = SNMP_TYPE_OBJECT
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q.Data.VarBinding.ValueLen = 0x08
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q.Data.VarBinding.ObjectValue = 0x000001010201062b
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q.Data.VarBinding.NullValue = SNMP_TYPE_NULL
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q.Data.VarBinding.EndIndicator = 0x00
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writer := new(bytes.Buffer)
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binary.Write(writer, binary.LittleEndian, q)
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snmpMatcher.packets = append(snmpMatcher.packets, packet.NewPacket(writer.Bytes(), writer.Len()))
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return snmpMatcher
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}
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func (t *SNMPv2Matcher) ServiceName() string {
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return "SNMP"
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}
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func (t *SNMPv2Matcher) PacketCount() int {
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return len(t.packets)
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}
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func (t *SNMPv2Matcher) Packet(index int) *packet.Packet {
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return t.packets[index]
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}
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func (t *SNMPv2Matcher) IsError(index int, packet *packet.Packet, info scaninfo.ServiceScanInfo) bool {
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return false
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}
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func (t *SNMPv2Matcher) IsNoResponse(index int) bool {
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return false
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}
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func (t *SNMPv2Matcher) IsPrePacket() bool {
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return false
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}
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func (t *SNMPv2Matcher) Match(index int, packet *packet.Packet, info scaninfo.ServiceScanInfo) bool {
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if packet == nil {
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return false
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}
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r := new(bytes.Buffer)
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r.Write(packet.Buffer)
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s := snmpv2{}
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if err := binary.Read(r, binary.BigEndian, &s); err != nil {
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return false
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}
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if s.StartSeq != SNMP_START_SEQUENCE {
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return false
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}
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var p uint8
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reader := new(bytes.Buffer)
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reader.Write(packet.Buffer)
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for idx := 0; idx < 5; idx++ {
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if err := binary.Read(reader, binary.BigEndian, &p); err != nil {
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return false
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}
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if p == SNMP_TYPE_INTEGER {
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break
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}
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p++
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}
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//finding protocol version type : 0x02 0x01 0x01
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if err := binary.Read(reader, binary.BigEndian, &p); err != nil {
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return false
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}
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if p == 0x01 {
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if err := binary.Read(reader, binary.BigEndian, &p); err != nil {
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return false
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}
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if p == 0x01 {
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return true
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}
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}
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return false
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}
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func (t *SNMPv2Matcher) IsSend(port int) bool {
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if port == 161 {
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return true
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}
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return false
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}
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