Files
akvorado/outlet/flow/decoder/netflow/decode.go
2025-09-29 05:37:19 +02:00

412 lines
15 KiB
Go

// SPDX-FileCopyrightText: 2023 Free Mobile
// SPDX-FileCopyrightText: 2021 NetSampler
// SPDX-License-Identifier: AGPL-3.0-only AND BSD-3-Clause
package netflow
import (
"bytes"
"encoding/binary"
"net/netip"
"akvorado/common/helpers"
"akvorado/common/pb"
"akvorado/common/schema"
"akvorado/outlet/flow/decoder"
"github.com/bits-and-blooms/bitset"
"github.com/netsampler/goflow2/v2/decoders/netflow"
"github.com/netsampler/goflow2/v2/decoders/netflowlegacy"
)
// When decoding, we use IPFIX information element identifiers. However, it
// should be noted, as per RFC 5102, IPFIX "Information Element identifier
// values in the sub-range of 1-127 are compatible with field types used by
// NetFlow version 9 [RFC3954]."
// Used for RFC 5103
type direction uint
const (
reversePEN = 29305
directionForward direction = iota
directionReverse
)
func (nd *Decoder) decodeNFv5(packet *netflowlegacy.PacketNetFlowV5, ts, sysUptime uint64, options decoder.Option, bf *schema.FlowMessage, finalize decoder.FinalizeFlowFunc) {
for _, record := range packet.Records {
bf.SamplingRate = uint64(packet.SamplingInterval)
bf.InIf = uint32(record.Input)
bf.OutIf = uint32(record.Output)
bf.SrcAddr = decodeIPFromUint32(uint32(record.SrcAddr))
bf.DstAddr = decodeIPFromUint32(uint32(record.DstAddr))
bf.NextHop = decodeIPFromUint32(uint32(record.NextHop))
bf.SrcNetMask = record.SrcMask
bf.DstNetMask = record.DstMask
bf.SrcAS = uint32(record.SrcAS)
bf.DstAS = uint32(record.DstAS)
bf.AppendUint(schema.ColumnBytes, uint64(record.DOctets))
bf.AppendUint(schema.ColumnPackets, uint64(record.DPkts))
bf.AppendUint(schema.ColumnEType, helpers.ETypeIPv4)
bf.AppendUint(schema.ColumnProto, uint64(record.Proto))
bf.AppendUint(schema.ColumnSrcPort, uint64(record.SrcPort))
bf.AppendUint(schema.ColumnDstPort, uint64(record.DstPort))
if !nd.d.Schema.IsDisabled(schema.ColumnGroupL3L4) {
bf.AppendUint(schema.ColumnIPTos, uint64(record.Tos))
bf.AppendUint(schema.ColumnTCPFlags, uint64(record.TCPFlags))
}
if options.TimestampSource == pb.RawFlow_TS_NETFLOW_FIRST_SWITCHED {
bf.TimeReceived = uint32(ts - sysUptime + uint64(record.First))
}
if bf.SamplingRate == 0 {
bf.SamplingRate = 1
}
finalize()
}
}
func (nd *Decoder) decodeNFv9IPFIX(version uint16, obsDomainID uint32, flowSets []any, samplingRateSys *samplingRateSystem, ts, sysUptime uint64, options decoder.Option, bf *schema.FlowMessage, finalize decoder.FinalizeFlowFunc) {
// Look for sampling rate in option data flowsets
for _, flowSet := range flowSets {
switch tFlowSet := flowSet.(type) {
case netflow.OptionsDataFlowSet:
for _, record := range tFlowSet.Records {
var (
samplingRate uint32
samplerID uint64
packetInterval, packetSpace uint32
)
for _, field := range record.OptionsValues {
v, ok := field.Value.([]byte)
if !ok || field.PenProvided {
continue
}
switch field.Type {
case netflow.IPFIX_FIELD_samplingInterval, netflow.IPFIX_FIELD_samplerRandomInterval:
samplingRate = uint32(decodeUNumber(v))
case netflow.IPFIX_FIELD_samplerId, netflow.IPFIX_FIELD_selectorId:
samplerID = uint64(decodeUNumber(v))
case netflow.IPFIX_FIELD_samplingPacketInterval:
packetInterval = uint32(decodeUNumber(v))
case netflow.IPFIX_FIELD_samplingPacketSpace:
packetSpace = uint32(decodeUNumber(v))
}
}
if packetInterval > 0 {
samplingRate = (packetInterval + packetSpace) / packetInterval
}
if samplingRate > 0 {
samplingRateSys.SetSamplingRate(version, obsDomainID, samplerID, samplingRate)
}
}
case netflow.DataFlowSet:
for _, record := range tFlowSet.Records {
nd.decodeRecord(version, obsDomainID, samplingRateSys, record.Values, ts, sysUptime, options, bf, finalize)
}
}
}
}
func (nd *Decoder) decodeRecord(version uint16, obsDomainID uint32, samplingRateSys *samplingRateSystem, fields []netflow.DataField, ts, sysUptime uint64, options decoder.Option, bf *schema.FlowMessage, finalize decoder.FinalizeFlowFunc) {
var foundReverseElement bool
reversePresent := bitset.New(65535)
for _, dir := range []direction{directionForward, directionReverse} {
var etype, dstPort, srcPort uint16
var proto, icmpType, icmpCode uint8
var foundIcmpTypeCode bool
mplsLabels := make([]uint32, 0, 5)
dataLinkFrameSectionIdx := -1
for idx, field := range fields {
v, ok := field.Value.([]byte)
if !ok {
continue
}
// RFC 5103 handling.
if field.PenProvided {
if field.Pen != reversePEN {
continue
}
if dir == directionForward {
// Reverse PEN and current direction is forward. Record we saw it and skip it.
foundReverseElement = true
reversePresent.Set(uint(field.Type))
continue
}
} else if dir == directionReverse && reversePresent.Test(uint(field.Type)) {
// No reverse PEN but we saw this one and so we should use the reversed value.
continue
}
switch field.Type {
// Statistics
case netflow.IPFIX_FIELD_octetDeltaCount, netflow.IPFIX_FIELD_postOctetDeltaCount, netflow.IPFIX_FIELD_initiatorOctets, netflow.IPFIX_FIELD_responderOctets:
bf.AppendUint(schema.ColumnBytes, decodeUNumber(v))
case netflow.IPFIX_FIELD_packetDeltaCount, netflow.IPFIX_FIELD_postPacketDeltaCount:
n := decodeUNumber(v)
if dir == directionReverse && n == 0 {
// We are in the reverse direction, but the flow is empty.
bf.Undo()
return
}
bf.AppendUint(schema.ColumnPackets, n)
case netflow.IPFIX_FIELD_samplingInterval, netflow.IPFIX_FIELD_samplerRandomInterval:
bf.SamplingRate = decodeUNumber(v)
case netflow.IPFIX_FIELD_samplerId, netflow.IPFIX_FIELD_selectorId:
bf.SamplingRate = uint64(samplingRateSys.GetSamplingRate(version, obsDomainID, decodeUNumber(v)))
// L3
case netflow.IPFIX_FIELD_sourceIPv4Address:
if !isAllZeroIP(v) {
etype = helpers.ETypeIPv4
bf.SrcAddr = decodeIPFromBytes(v)
}
case netflow.IPFIX_FIELD_destinationIPv4Address:
if !isAllZeroIP(v) {
etype = helpers.ETypeIPv4
bf.DstAddr = decodeIPFromBytes(v)
}
case netflow.IPFIX_FIELD_sourceIPv6Address:
if !isAllZeroIP(v) {
etype = helpers.ETypeIPv6
bf.SrcAddr = decodeIPFromBytes(v)
}
case netflow.IPFIX_FIELD_destinationIPv6Address:
if !isAllZeroIP(v) {
etype = helpers.ETypeIPv6
bf.DstAddr = decodeIPFromBytes(v)
}
case netflow.IPFIX_FIELD_sourceIPv4PrefixLength, netflow.IPFIX_FIELD_sourceIPv6PrefixLength:
bf.SrcNetMask = uint8(decodeUNumber(v))
case netflow.IPFIX_FIELD_destinationIPv4PrefixLength, netflow.IPFIX_FIELD_destinationIPv6PrefixLength:
bf.DstNetMask = uint8(decodeUNumber(v))
case netflow.IPFIX_FIELD_ipNextHopIPv4Address, netflow.IPFIX_FIELD_bgpNextHopIPv4Address, netflow.IPFIX_FIELD_ipNextHopIPv6Address, netflow.IPFIX_FIELD_bgpNextHopIPv6Address:
bf.NextHop = decodeIPFromBytes(v)
// L4
case netflow.IPFIX_FIELD_sourceTransportPort:
srcPort = uint16(decodeUNumber(v))
bf.AppendUint(schema.ColumnSrcPort, uint64(srcPort))
case netflow.IPFIX_FIELD_destinationTransportPort:
dstPort = uint16(decodeUNumber(v))
bf.AppendUint(schema.ColumnDstPort, uint64(dstPort))
case netflow.IPFIX_FIELD_protocolIdentifier:
proto = uint8(decodeUNumber(v))
bf.AppendUint(schema.ColumnProto, uint64(proto))
// Network
case netflow.IPFIX_FIELD_bgpSourceAsNumber:
bf.SrcAS = uint32(decodeUNumber(v))
case netflow.IPFIX_FIELD_bgpDestinationAsNumber:
bf.DstAS = uint32(decodeUNumber(v))
// Interfaces
case netflow.IPFIX_FIELD_ingressInterface:
bf.InIf = uint32(decodeUNumber(v))
case netflow.IPFIX_FIELD_egressInterface:
bf.OutIf = uint32(decodeUNumber(v))
case netflow.IPFIX_FIELD_ingressPhysicalInterface:
if bf.InIf == 0 {
bf.InIf = uint32(decodeUNumber(v))
}
case netflow.IPFIX_FIELD_egressPhysicalInterface:
if bf.OutIf == 0 {
bf.OutIf = uint32(decodeUNumber(v))
}
// RFC7133: process it later to not override other fields
case netflow.IPFIX_FIELD_dataLinkFrameSize:
// We are going to ignore it as we don't know L3 size yet.
case netflow.IPFIX_FIELD_dataLinkFrameSection:
dataLinkFrameSectionIdx = idx
// MPLS
case netflow.IPFIX_FIELD_mplsTopLabelStackSection, netflow.IPFIX_FIELD_mplsLabelStackSection2, netflow.IPFIX_FIELD_mplsLabelStackSection3, netflow.IPFIX_FIELD_mplsLabelStackSection4, netflow.IPFIX_FIELD_mplsLabelStackSection5, netflow.IPFIX_FIELD_mplsLabelStackSection6, netflow.IPFIX_FIELD_mplsLabelStackSection7, netflow.IPFIX_FIELD_mplsLabelStackSection8, netflow.IPFIX_FIELD_mplsLabelStackSection9, netflow.IPFIX_FIELD_mplsLabelStackSection10:
uv := decodeUNumber(v) >> 4
if uv > 0 {
mplsLabels = append(mplsLabels, uint32(uv))
}
// Remaining
case netflow.IPFIX_FIELD_forwardingStatus:
bf.AppendUint(schema.ColumnForwardingStatus, decodeUNumber(v))
default:
if options.TimestampSource == pb.RawFlow_TS_NETFLOW_FIRST_SWITCHED {
switch field.Type {
case netflow.NFV9_FIELD_FIRST_SWITCHED:
bf.TimeReceived = uint32(ts - sysUptime + decodeUNumber(v))
case netflow.IPFIX_FIELD_flowStartSeconds:
bf.TimeReceived = uint32(decodeUNumber(v))
case netflow.IPFIX_FIELD_flowStartMilliseconds:
bf.TimeReceived = uint32(decodeUNumber(v) / 1000)
case netflow.IPFIX_FIELD_flowStartMicroseconds:
bf.TimeReceived = uint32(decodeUNumber(v) / 1_000_000)
case netflow.IPFIX_FIELD_flowStartNanoseconds:
bf.TimeReceived = uint32(ts + decodeUNumber(v)/1_000_000_000)
}
}
if !nd.d.Schema.IsDisabled(schema.ColumnGroupNAT) {
// NAT
switch field.Type {
case netflow.IPFIX_FIELD_postNATSourceIPv4Address:
bf.AppendIPv6(schema.ColumnSrcAddrNAT, decodeIPFromBytes(v))
case netflow.IPFIX_FIELD_postNATDestinationIPv4Address:
bf.AppendIPv6(schema.ColumnDstAddrNAT, decodeIPFromBytes(v))
case netflow.IPFIX_FIELD_postNAPTSourceTransportPort:
bf.AppendUint(schema.ColumnSrcPortNAT, decodeUNumber(v))
case netflow.IPFIX_FIELD_postNAPTDestinationTransportPort:
bf.AppendUint(schema.ColumnDstPortNAT, decodeUNumber(v))
}
}
if !nd.d.Schema.IsDisabled(schema.ColumnGroupL2) {
// L2
switch field.Type {
case netflow.IPFIX_FIELD_vlanId, netflow.IPFIX_FIELD_dot1qVlanId:
if bf.SrcVlan == 0 {
bf.SrcVlan = uint16(decodeUNumber(v))
}
case netflow.IPFIX_FIELD_postVlanId, netflow.IPFIX_FIELD_postDot1qVlanId:
if bf.DstVlan == 0 {
bf.DstVlan = uint16(decodeUNumber(v))
}
case netflow.IPFIX_FIELD_sourceMacAddress:
bf.AppendUint(schema.ColumnSrcMAC, decodeUNumber(v))
case netflow.IPFIX_FIELD_destinationMacAddress:
bf.AppendUint(schema.ColumnDstMAC, decodeUNumber(v))
case netflow.IPFIX_FIELD_postSourceMacAddress:
bf.AppendUint(schema.ColumnSrcMAC, decodeUNumber(v))
case netflow.IPFIX_FIELD_postDestinationMacAddress:
bf.AppendUint(schema.ColumnDstMAC, decodeUNumber(v))
}
}
if !nd.d.Schema.IsDisabled(schema.ColumnGroupL3L4) {
// Misc L3/L4 fields
switch field.Type {
case netflow.IPFIX_FIELD_ipTTL, netflow.IPFIX_FIELD_minimumTTL:
bf.AppendUint(schema.ColumnIPTTL, decodeUNumber(v))
case netflow.IPFIX_FIELD_ipClassOfService:
bf.AppendUint(schema.ColumnIPTos, decodeUNumber(v))
case netflow.IPFIX_FIELD_flowLabelIPv6:
bf.AppendUint(schema.ColumnIPv6FlowLabel, decodeUNumber(v))
case netflow.IPFIX_FIELD_tcpControlBits:
bf.AppendUint(schema.ColumnTCPFlags, decodeUNumber(v))
case netflow.IPFIX_FIELD_fragmentIdentification:
bf.AppendUint(schema.ColumnIPFragmentID, decodeUNumber(v))
case netflow.IPFIX_FIELD_fragmentOffset:
bf.AppendUint(schema.ColumnIPFragmentOffset, decodeUNumber(v))
// ICMP
case netflow.IPFIX_FIELD_icmpTypeCodeIPv4, netflow.IPFIX_FIELD_icmpTypeCodeIPv6:
icmpTypeCode := decodeUNumber(v)
icmpType = uint8(icmpTypeCode >> 8)
icmpCode = uint8(icmpTypeCode & 0xff)
foundIcmpTypeCode = true
case netflow.IPFIX_FIELD_icmpTypeIPv4, netflow.IPFIX_FIELD_icmpTypeIPv6:
icmpType = uint8(decodeUNumber(v))
foundIcmpTypeCode = true
case netflow.IPFIX_FIELD_icmpCodeIPv4, netflow.IPFIX_FIELD_icmpCodeIPv6:
icmpCode = uint8(decodeUNumber(v))
foundIcmpTypeCode = true
}
}
}
}
if dataLinkFrameSectionIdx >= 0 {
data := fields[dataLinkFrameSectionIdx].Value.([]byte)
if l3Length := decoder.ParseEthernet(nd.d.Schema, bf, data); l3Length > 0 {
bf.AppendUint(schema.ColumnBytes, l3Length)
bf.AppendUint(schema.ColumnPackets, 1)
}
}
if !nd.d.Schema.IsDisabled(schema.ColumnGroupL3L4) && (proto == 1 || proto == 58) {
// ICMP
if !foundIcmpTypeCode {
// Some implementations may use source and destination ports, some
// other only destination port. The following heuristic is safe as
// the only valid code for type 0 is 0 (echo reply).
if srcPort == 0 {
// Use destination port instead (Cisco on NFv5 that still exists
// today with NFv9 and IPFIX).
icmpType = uint8(dstPort >> 8)
icmpCode = uint8(dstPort & 0xff)
}
// Unsure how to do the mapping when using source and destination
// port. Let's ignore.
}
if proto == 1 {
bf.AppendUint(schema.ColumnICMPv4Type, uint64(icmpType))
bf.AppendUint(schema.ColumnICMPv4Code, uint64(icmpCode))
} else {
bf.AppendUint(schema.ColumnICMPv6Type, uint64(icmpType))
bf.AppendUint(schema.ColumnICMPv6Code, uint64(icmpCode))
}
}
bf.AppendUint(schema.ColumnEType, uint64(etype))
if len(mplsLabels) > 0 {
bf.AppendArrayUInt32(schema.ColumnMPLSLabels, mplsLabels)
}
if bf.SamplingRate == 0 {
bf.SamplingRate = uint64(samplingRateSys.GetSamplingRate(version, obsDomainID, 0))
}
if dir == directionForward && !foundReverseElement {
finalize()
break
} else if dir == directionForward {
finalize()
bf.Reverse()
} else {
bf.Reverse()
finalize()
}
}
}
func decodeUNumber(b []byte) uint64 {
l := len(b)
switch l {
case 1:
return uint64(b[0])
case 2:
return uint64(b[1]) | uint64(b[0])<<8
case 3:
return uint64(b[2]) | uint64(b[1])<<8 | uint64(b[0])<<16
case 4:
return uint64(b[3]) | uint64(b[2])<<8 | uint64(b[1])<<16 | uint64(b[0])<<24
case 5:
return uint64(b[4]) | uint64(b[3])<<8 | uint64(b[2])<<16 | uint64(b[1])<<24 | uint64(b[0])<<32
case 6:
return uint64(b[5]) | uint64(b[4])<<8 | uint64(b[3])<<16 | uint64(b[2])<<24 | uint64(b[1])<<32 | uint64(b[0])<<40
case 7:
return uint64(b[6]) | uint64(b[5])<<8 | uint64(b[4])<<16 | uint64(b[3])<<24 | uint64(b[2])<<32 | uint64(b[1])<<40 | uint64(b[0])<<48
case 8:
return binary.BigEndian.Uint64(b)
}
return 0
}
func decodeIPFromBytes(b []byte) netip.Addr {
if ip, ok := netip.AddrFromSlice(b); ok {
return netip.AddrFrom16(ip.As16())
}
return netip.Addr{}
}
var (
allZeroIPv4Bytes = netip.MustParseAddr("0.0.0.0").AsSlice()
allZeroIPv6Bytes = netip.MustParseAddr("::").AsSlice()
)
func isAllZeroIP(b []byte) bool {
return len(b) == 4 && bytes.Equal(b, allZeroIPv4Bytes) ||
len(b) == 16 && bytes.Equal(b, allZeroIPv6Bytes)
}
func decodeIPFromUint32(ipv4 uint32) netip.Addr {
var ipBytes [4]byte
binary.BigEndian.PutUint32(ipBytes[:], ipv4)
return netip.AddrFrom16(netip.AddrFrom4(ipBytes).As16())
}