480 lines
13 KiB
Go
480 lines
13 KiB
Go
package sflow
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import (
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"encoding/binary"
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"errors"
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"fmt"
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"io"
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"github.com/influxdata/telegraf"
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"github.com/influxdata/telegraf/plugins/inputs/sflow/binaryio"
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)
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type packetDecoder struct {
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onPacketF func(p *v5Format)
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Log telegraf.Logger
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}
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func newDecoder() *packetDecoder {
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return &packetDecoder{}
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}
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func (d *packetDecoder) debug(args ...interface{}) {
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if d.Log != nil {
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d.Log.Debug(args...)
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}
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}
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func (d *packetDecoder) onPacket(f func(p *v5Format)) {
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d.onPacketF = f
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}
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func (d *packetDecoder) decode(r io.Reader) error {
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var err error
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var packet *v5Format
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for err == nil {
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packet, err = d.decodeOnePacket(r)
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if err != nil {
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break
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}
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d.onPacketF(packet)
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}
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if err != nil && errors.Is(err, io.EOF) {
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return nil
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}
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return err
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}
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type addressType uint32 // must be uint32
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const (
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addressTypeUnknown addressType = 0
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addressTypeIPV4 addressType = 1
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addressTypeIPV6 addressType = 2
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)
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func (d *packetDecoder) decodeOnePacket(r io.Reader) (*v5Format, error) {
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p := &v5Format{}
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err := read(r, &p.version, "version")
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if err != nil {
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return nil, err
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}
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if p.version != 5 {
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return nil, fmt.Errorf("version %d not supported, only version 5", p.version)
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}
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var addressIPType addressType
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if err := read(r, &addressIPType, "address ip type"); err != nil {
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return nil, err
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}
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switch addressIPType {
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case addressTypeUnknown:
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p.agentAddress.IP = make([]byte, 0)
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case addressTypeIPV4:
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p.agentAddress.IP = make([]byte, 4)
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case addressTypeIPV6:
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p.agentAddress.IP = make([]byte, 16)
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default:
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return nil, fmt.Errorf("unknown address IP type %d", addressIPType)
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}
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if err := read(r, &p.agentAddress.IP, "Agent Address IP"); err != nil {
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return nil, err
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}
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if err := read(r, &p.subAgentID, "SubAgentID"); err != nil {
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return nil, err
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}
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if err := read(r, &p.sequenceNumber, "SequenceNumber"); err != nil {
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return nil, err
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}
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if err := read(r, &p.uptime, "Uptime"); err != nil {
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return nil, err
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}
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p.samples, err = d.decodeSamples(r)
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return p, err
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}
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func (d *packetDecoder) decodeSamples(r io.Reader) ([]sample, error) {
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// # of samples
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var numOfSamples uint32
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if err := read(r, &numOfSamples, "sample count"); err != nil {
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return nil, err
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}
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result := make([]sample, 0, numOfSamples)
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for i := 0; i < int(numOfSamples); i++ {
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sam, err := d.decodeSample(r)
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if err != nil {
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return result, err
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}
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result = append(result, sam)
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}
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return result, nil
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}
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func (d *packetDecoder) decodeSample(r io.Reader) (sample, error) {
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var err error
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sam := sample{}
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if err := read(r, &sam.smplType, "sampleType"); err != nil {
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return sam, err
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}
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sampleDataLen := uint32(0)
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if err := read(r, &sampleDataLen, "Sample data length"); err != nil {
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return sam, err
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}
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mr := binaryio.MinReader(r, int64(sampleDataLen))
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defer mr.Close()
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switch sam.smplType {
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case sampleTypeFlowSample:
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sam.smplData, err = d.decodeFlowSample(mr)
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case sampleTypeFlowSampleExpanded:
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sam.smplData, err = d.decodeFlowSampleExpanded(mr)
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default:
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d.debug("Unknown sample type: ", sam.smplType)
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}
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return sam, err
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}
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func (d *packetDecoder) decodeFlowSample(r io.Reader) (t sampleDataFlowSampleExpanded, err error) {
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if err := read(r, &t.sequenceNumber, "SequenceNumber"); err != nil {
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return t, err
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}
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var sourceID uint32
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if err := read(r, &sourceID, "SourceID"); err != nil { // source_id sflow_version_5.txt line: 1622
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return t, err
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}
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// split source id to source id type and source id index
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t.sourceIDIndex = sourceID & 0x00ffffff // sflow_version_5.txt line: 1468
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t.sourceIDType = sourceID >> 24 // source_id_type sflow_version_5.txt Line 1465
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if err := read(r, &t.samplingRate, "SamplingRate"); err != nil {
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return t, err
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}
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if err := read(r, &t.samplePool, "SamplePool"); err != nil {
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return t, err
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}
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if err := read(r, &t.drops, "Drops"); err != nil { // sflow_version_5.txt line 1636
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return t, err
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}
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if err := read(r, &t.inputIfIndex, "InputIfIndex"); err != nil {
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return t, err
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}
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t.inputIfFormat = t.inputIfIndex >> 30
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t.inputIfIndex = t.inputIfIndex & 0x3FFFFFFF
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if err := read(r, &t.outputIfIndex, "OutputIfIndex"); err != nil {
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return t, err
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}
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t.outputIfFormat = t.outputIfIndex >> 30
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t.outputIfIndex = t.outputIfIndex & 0x3FFFFFFF
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switch t.sourceIDIndex {
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case t.outputIfIndex:
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t.sampleDirection = "egress"
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case t.inputIfIndex:
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t.sampleDirection = "ingress"
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}
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t.flowRecords, err = d.decodeFlowRecords(r, t.samplingRate)
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return t, err
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}
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func (d *packetDecoder) decodeFlowSampleExpanded(r io.Reader) (t sampleDataFlowSampleExpanded, err error) {
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if err := read(r, &t.sequenceNumber, "SequenceNumber"); err != nil { // sflow_version_5.txt line 1701
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return t, err
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}
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if err := read(r, &t.sourceIDType, "SourceIDType"); err != nil { // sflow_version_5.txt line: 1706 + 16878
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return t, err
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}
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if err := read(r, &t.sourceIDIndex, "SourceIDIndex"); err != nil { // sflow_version_5.txt line: 1689
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return t, err
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}
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if err := read(r, &t.samplingRate, "SamplingRate"); err != nil { // sflow_version_5.txt line: 1707
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return t, err
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}
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if err := read(r, &t.samplePool, "SamplePool"); err != nil { // sflow_version_5.txt line: 1708
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return t, err
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}
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if err := read(r, &t.drops, "Drops"); err != nil { // sflow_version_5.txt line: 1712
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return t, err
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}
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if err := read(r, &t.inputIfFormat, "InputIfFormat"); err != nil { // sflow_version_5.txt line: 1727
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return t, err
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}
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if err := read(r, &t.inputIfIndex, "InputIfIndex"); err != nil {
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return t, err
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}
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if err := read(r, &t.outputIfFormat, "OutputIfFormat"); err != nil { // sflow_version_5.txt line: 1728
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return t, err
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}
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if err := read(r, &t.outputIfIndex, "OutputIfIndex"); err != nil {
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return t, err
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}
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switch t.sourceIDIndex {
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case t.outputIfIndex:
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t.sampleDirection = "egress"
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case t.inputIfIndex:
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t.sampleDirection = "ingress"
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}
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t.flowRecords, err = d.decodeFlowRecords(r, t.samplingRate)
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return t, err
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}
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func (d *packetDecoder) decodeFlowRecords(r io.Reader, samplingRate uint32) (recs []flowRecord, err error) {
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var flowDataLen uint32
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var count uint32
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if err := read(r, &count, "FlowRecord count"); err != nil {
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return recs, err
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}
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for i := uint32(0); i < count; i++ {
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fr := flowRecord{}
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if err := read(r, &fr.flowFormat, "FlowFormat"); err != nil { // sflow_version_5.txt line 1597
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return recs, err
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}
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if err := read(r, &flowDataLen, "Flow data length"); err != nil {
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return recs, err
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}
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mr := binaryio.MinReader(r, int64(flowDataLen))
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switch fr.flowFormat {
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case flowFormatTypeRawPacketHeader: // sflow_version_5.txt line 1938
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fr.flowData, err = d.decodeRawPacketHeaderFlowData(mr, samplingRate)
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default:
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d.debug("Unknown flow format: ", fr.flowFormat)
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}
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if err != nil {
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mr.Close()
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return recs, err
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}
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recs = append(recs, fr)
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mr.Close()
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}
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return recs, err
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}
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func (d *packetDecoder) decodeRawPacketHeaderFlowData(r io.Reader, samplingRate uint32) (h rawPacketHeaderFlowData, err error) {
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if err := read(r, &h.headerProtocol, "HeaderProtocol"); err != nil { // sflow_version_5.txt line 1940
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return h, err
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}
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if err := read(r, &h.frameLength, "FrameLength"); err != nil { // sflow_version_5.txt line 1942
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return h, err
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}
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h.bytes = h.frameLength * samplingRate
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if err := read(r, &h.strippedOctets, "StrippedOctets"); err != nil { // sflow_version_5.txt line 1967
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return h, err
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}
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if err := read(r, &h.headerLength, "HeaderLength"); err != nil {
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return h, err
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}
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mr := binaryio.MinReader(r, int64(h.headerLength))
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defer mr.Close()
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switch h.headerProtocol {
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case headerProtocolTypeEthernetISO88023:
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h.header, err = d.decodeEthHeader(mr)
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default:
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d.debug("Unknown header protocol type: ", h.headerProtocol)
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}
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return h, err
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}
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// ethHeader answers a decode Directive that will decode an ethernet frame header
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// according to https://en.wikipedia.org/wiki/Ethernet_frame
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func (d *packetDecoder) decodeEthHeader(r io.Reader) (h ethHeader, err error) {
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// we may have to read out StrippedOctets bytes and throw them away first?
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if err := read(r, &h.destinationMAC, "DestinationMAC"); err != nil {
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return h, err
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}
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if err := read(r, &h.sourceMAC, "SourceMAC"); err != nil {
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return h, err
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}
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var tagOrEType uint16
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if err := read(r, &tagOrEType, "tagOrEtype"); err != nil {
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return h, err
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}
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switch tagOrEType {
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case 0x8100: // could be?
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var discard uint16
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if err := read(r, &discard, "unknown"); err != nil {
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return h, err
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}
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if err := read(r, &h.etherTypeCode, "EtherTypeCode"); err != nil {
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return h, err
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}
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default:
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h.etherTypeCode = tagOrEType
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}
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h.etherType = eTypeMap[h.etherTypeCode]
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switch h.etherType {
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case "IPv4":
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h.ipHeader, err = d.decodeIPv4Header(r)
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case "IPv6":
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h.ipHeader, err = d.decodeIPv6Header(r)
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default:
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}
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if err != nil {
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return h, err
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}
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return h, err
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}
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// https://en.wikipedia.org/wiki/IPv4#Header
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func (d *packetDecoder) decodeIPv4Header(r io.Reader) (h ipV4Header, err error) {
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if err := read(r, &h.version, "Version"); err != nil {
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return h, err
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}
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h.internetHeaderLength = h.version & 0x0F
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h.version = h.version & 0xF0
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if err := read(r, &h.dscp, "DSCP"); err != nil {
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return h, err
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}
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h.ecn = h.dscp & 0x03
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h.dscp = h.dscp >> 2
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if err := read(r, &h.totalLength, "TotalLength"); err != nil {
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return h, err
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}
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if err := read(r, &h.identification, "Identification"); err != nil {
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return h, err
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}
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if err := read(r, &h.fragmentOffset, "FragmentOffset"); err != nil {
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return h, err
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}
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h.flags = uint8(h.fragmentOffset >> 13)
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h.fragmentOffset = h.fragmentOffset & 0x1FFF
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if err := read(r, &h.ttl, "TTL"); err != nil {
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return h, err
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}
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if err := read(r, &h.protocol, "Protocol"); err != nil {
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return h, err
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}
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if err := read(r, &h.headerChecksum, "HeaderChecksum"); err != nil {
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return h, err
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}
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if err := read(r, &h.sourceIP, "SourceIP"); err != nil {
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return h, err
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}
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if err := read(r, &h.destIP, "DestIP"); err != nil {
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return h, err
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}
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switch h.protocol {
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case ipProtocolTCP:
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h.protocolHeader, err = decodeTCPHeader(r)
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case ipProtocolUDP:
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h.protocolHeader, err = decodeUDPHeader(r)
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default:
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d.debug("Unknown IP protocol: ", h.protocol)
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}
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return h, err
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}
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// https://en.wikipedia.org/wiki/IPv6_packet
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func (d *packetDecoder) decodeIPv6Header(r io.Reader) (h ipV6Header, err error) {
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var fourByteBlock uint32
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if err := read(r, &fourByteBlock, "IPv6 header octet 0"); err != nil {
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return h, err
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}
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version := fourByteBlock >> 28
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if version != 0x6 {
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return h, fmt.Errorf("unexpected IPv6 header version 0x%x", version)
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}
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h.dscp = uint8((fourByteBlock & 0xFC00000) >> 22)
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h.ecn = uint8((fourByteBlock & 0x300000) >> 20)
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// The flowLabel is available via fourByteBlock & 0xFFFFF
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if err := read(r, &h.payloadLength, "PayloadLength"); err != nil {
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return h, err
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}
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if err := read(r, &h.nextHeaderProto, "NextHeaderProto"); err != nil {
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return h, err
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}
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if err := read(r, &h.hopLimit, "HopLimit"); err != nil {
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return h, err
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}
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if err := read(r, &h.sourceIP, "SourceIP"); err != nil {
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return h, err
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}
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if err := read(r, &h.destIP, "DestIP"); err != nil {
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return h, err
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}
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switch h.nextHeaderProto {
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case ipProtocolTCP:
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h.protocolHeader, err = decodeTCPHeader(r)
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case ipProtocolUDP:
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h.protocolHeader, err = decodeUDPHeader(r)
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default:
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// not handled
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d.debug("Unknown IP protocol: ", h.nextHeaderProto)
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}
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return h, err
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}
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// https://en.wikipedia.org/wiki/Transmission_Control_Protocol#TCP_segment_structure
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func decodeTCPHeader(r io.Reader) (h tcpHeader, err error) {
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if err := read(r, &h.sourcePort, "SourcePort"); err != nil {
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return h, err
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}
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if err := read(r, &h.destinationPort, "DestinationPort"); err != nil {
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return h, err
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}
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if err := read(r, &h.sequence, "Sequence"); err != nil {
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return h, err
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}
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if err := read(r, &h.ackNumber, "AckNumber"); err != nil {
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return h, err
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}
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// Next up: bit reading!
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// data offset 4 bits
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// reserved 3 bits
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// flags 9 bits
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var dataOffsetAndReservedAndFlags uint16
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if err := read(r, &dataOffsetAndReservedAndFlags, "TCP Header Octet offset 12"); err != nil {
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return h, err
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}
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h.tcpHeaderLength = uint8((dataOffsetAndReservedAndFlags >> 12) * 4)
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h.flags = dataOffsetAndReservedAndFlags & 0x1FF
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// done bit reading
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if err := read(r, &h.tcpWindowSize, "TCPWindowSize"); err != nil {
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return h, err
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}
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if err := read(r, &h.checksum, "Checksum"); err != nil {
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return h, err
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}
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if err := read(r, &h.tcpUrgentPointer, "TCPUrgentPointer"); err != nil {
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return h, err
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}
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return h, err
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}
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func decodeUDPHeader(r io.Reader) (h udpHeader, err error) {
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if err := read(r, &h.sourcePort, "SourcePort"); err != nil {
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return h, err
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}
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if err := read(r, &h.destinationPort, "DestinationPort"); err != nil {
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return h, err
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}
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if err := read(r, &h.udpLength, "UDPLength"); err != nil {
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return h, err
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}
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if err := read(r, &h.checksum, "Checksum"); err != nil {
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return h, err
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}
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return h, err
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}
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func read(r io.Reader, data interface{}, name string) error {
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err := binary.Read(r, binary.BigEndian, data)
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if err != nil {
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return fmt.Errorf("failed to read %q: %w", name, err)
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}
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return nil
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}
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