mirror of
https://github.com/soypat/lneto.git
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soypat
1081 lines
27 KiB
Go
1081 lines
27 KiB
Go
package pcap
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//go:generate stringer -type=FieldClass -linecomment -output stringers.go .
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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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"math"
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"github.com/soypat/lneto"
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"github.com/soypat/lneto/arp"
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"github.com/soypat/lneto/dhcpv4"
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"github.com/soypat/lneto/dns"
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"github.com/soypat/lneto/ethernet"
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"github.com/soypat/lneto/http/httpraw"
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"github.com/soypat/lneto/ipv4"
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"github.com/soypat/lneto/ipv6"
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"github.com/soypat/lneto/ntp"
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"github.com/soypat/lneto/tcp"
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"github.com/soypat/lneto/udp"
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)
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const unknownPayloadProto = "payload?"
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type PacketBreakdown struct {
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hdr httpraw.Header
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dmsg dns.Message
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vld lneto.Validator
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}
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func (pc *PacketBreakdown) CaptureEthernet(dst []Frame, pkt []byte, bitOffset int) ([]Frame, error) {
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if bitOffset%8 != 0 {
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return dst, errors.New("ethernet must be parsed at byte boundary")
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}
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efrm, err := ethernet.NewFrame(pkt[bitOffset/8:])
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if err != nil {
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return dst, err
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}
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efrm.ValidateSize(pc.validator())
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if pc.validator().HasError() {
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return dst, pc.validator().ErrPop()
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}
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finfo := Frame{
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Protocol: "Ethernet",
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PacketBitOffset: bitOffset,
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}
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finfo.Fields = append(finfo.Fields, baseEthernetFields[:]...)
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etype := efrm.EtherTypeOrSize()
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end := 14*octet + bitOffset
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if etype.IsSize() {
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finfo.Fields[len(finfo.Fields)-1].Class = FieldClassSize
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dst = append(dst, finfo)
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dst = append(dst, remainingFrameInfo("Ethernet payload", FieldClassPayload, end, octet*len(pkt)))
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return dst, nil
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}
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dst = append(dst, finfo)
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if efrm.IsVLAN() {
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finfo.Fields = append(finfo.Fields, FrameField{Name: "VLAN Tag", Class: FieldClassType, FrameBitOffset: end, BitLength: 2 * octet})
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dst = append(dst, remainingFrameInfo("Ethernet VLAN", FieldClassPayload, end+2*octet, octet*len(pkt)))
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return dst, nil
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}
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switch etype {
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case ethernet.TypeARP:
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dst, err = pc.CaptureARP(dst, pkt, end)
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case ethernet.TypeIPv4:
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dst, err = pc.CaptureIPv4(dst, pkt, end)
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case ethernet.TypeIPv6:
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dst, err = pc.CaptureIPv6(dst, pkt, end)
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default:
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dst = append(dst, remainingFrameInfo(etype, FieldClassPayload, end, octet*len(pkt)))
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}
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return dst, err
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}
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func (pc *PacketBreakdown) CaptureARP(dst []Frame, pkt []byte, bitOffset int) ([]Frame, error) {
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if bitOffset%8 != 0 {
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return dst, errors.New("ARP must be parsed at byte boundary")
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}
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afrm, err := arp.NewFrame(pkt[bitOffset/8:])
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if err != nil {
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return dst, err
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}
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afrm.ValidateSize(pc.validator())
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if pc.validator().HasError() {
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return dst, pc.validator().ErrPop()
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}
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finfo := Frame{
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Protocol: ethernet.TypeARP,
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PacketBitOffset: bitOffset,
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}
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const varstart = 8 * octet
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finfo.Fields = append(finfo.Fields, baseARPFields[:]...)
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_, hlen := afrm.Hardware()
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_, plen := afrm.Protocol()
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finfo.Fields = append(finfo.Fields,
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FrameField{
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Name: "Sender hardware address",
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Class: FieldClassSrc,
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FrameBitOffset: varstart,
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BitLength: int(hlen) * octet,
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},
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FrameField{
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Name: "Sender protocol address",
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Class: FieldClassSrc,
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FrameBitOffset: int(hlen)*octet + varstart,
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BitLength: int(plen) * octet,
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},
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FrameField{
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Name: "Target hardware address",
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Class: FieldClassSrc,
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FrameBitOffset: int(hlen+plen)*octet + varstart,
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BitLength: int(hlen) * octet,
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},
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FrameField{
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Name: "Target protocol address",
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Class: FieldClassSrc,
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FrameBitOffset: (2*int(hlen)+int(plen))*octet + varstart,
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BitLength: int(plen) * octet,
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},
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)
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dst = append(dst, finfo)
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return dst, nil
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}
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func (pc *PacketBreakdown) CaptureIPv6(dst []Frame, pkt []byte, bitOffset int) ([]Frame, error) {
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if bitOffset%8 != 0 {
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return dst, errors.New("IPv6 must be parsed at byte boundary")
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}
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ifrm6, err := ipv6.NewFrame(pkt[bitOffset/8:])
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if err != nil {
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return dst, err
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}
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ifrm6.ValidateSize(pc.validator())
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if pc.validator().HasError() {
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return dst, pc.validator().ErrPop()
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}
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finfo := Frame{
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Protocol: ethernet.TypeIPv6,
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PacketBitOffset: bitOffset,
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}
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finfo.Fields = append(finfo.Fields, baseIPv6Fields[:]...)
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dst = append(dst, finfo)
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proto := ifrm6.NextHeader()
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end := bitOffset + 40*octet
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var protoErrs []error
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var crc lneto.CRC791
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if proto == lneto.IPProtoTCP {
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ifrm6.CRCWritePseudo(&crc)
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tfrm, err := tcp.NewFrame(ifrm6.Payload())
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if err == nil {
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tfrm.CRCWrite(&crc)
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wantSum := crc.Sum16()
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gotSum := tfrm.CRC()
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if wantSum != gotSum {
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protoErrs = append(protoErrs, &crcError16{protocol: "ipv6+tcp", want: wantSum, got: gotSum})
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}
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}
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} else if proto == lneto.IPProtoUDP || proto == lneto.IPProtoUDPLite {
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ifrm6.CRCWritePseudo(&crc)
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ufrm, err := udp.NewFrame(ifrm6.Payload())
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if err == nil {
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ufrm.CRCWriteIPv6(&crc)
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wantSum := crc.Sum16()
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gotSum := ufrm.CRC()
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if wantSum != gotSum {
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protoErrs = append(protoErrs, &crcError16{protocol: "ipv6+udp", want: wantSum, got: gotSum})
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}
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}
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}
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return pc.captureIPProto(proto, dst, pkt, end, protoErrs...)
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}
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func (pc *PacketBreakdown) CaptureIPv4(dst []Frame, pkt []byte, bitOffset int) ([]Frame, error) {
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if bitOffset%8 != 0 {
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return dst, errors.New("IPv4 must be parsed at byte boundary")
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}
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ifrm4, err := ipv4.NewFrame(pkt[bitOffset/8:])
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if err != nil {
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return dst, err
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}
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ifrm4.ValidateSize(pc.validator())
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if pc.validator().HasError() {
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return dst, pc.validator().ErrPop()
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}
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finfo := Frame{
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Protocol: ethernet.TypeIPv4,
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PacketBitOffset: bitOffset,
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}
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finfo.Fields = append(finfo.Fields, baseIPv4Fields[:]...)
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options := ifrm4.Options()
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if len(options) > 0 {
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finfo.Fields = append(finfo.Fields, FrameField{
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Class: FieldClassOptions,
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FrameBitOffset: 20 * octet,
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BitLength: octet * len(options),
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})
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}
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gotSum := ifrm4.CRC()
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wantSum := ifrm4.CalculateHeaderCRC()
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if gotSum != wantSum {
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finfo.Errors = append(finfo.Errors, &crcError16{protocol: "ipv4", want: wantSum, got: gotSum})
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}
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dst = append(dst, finfo)
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proto := ifrm4.Protocol()
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end := bitOffset + octet*ifrm4.HeaderLength()
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var protoErrs []error
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var crc lneto.CRC791
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if proto == lneto.IPProtoTCP {
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ifrm4.CRCWriteTCPPseudo(&crc)
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tfrm, err := tcp.NewFrame(ifrm4.Payload())
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if err == nil {
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tfrm.ValidateSize(pc.validator())
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if pc.vld.HasError() {
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println("BAD TCP")
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return dst, pc.vld.ErrPop()
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}
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tfrm.CRCWrite(&crc)
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wantSum := crc.Sum16()
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gotSum := tfrm.CRC()
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if wantSum != gotSum {
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protoErrs = append(protoErrs, &crcError16{protocol: "ipv4+tcp", want: wantSum, got: gotSum})
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}
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}
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} else if proto == lneto.IPProtoUDP {
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ifrm4.CRCWriteUDPPseudo(&crc)
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ufrm, err := udp.NewFrame(ifrm4.Payload())
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if err == nil {
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ufrm.ValidateSize(pc.validator())
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if pc.vld.HasError() {
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println("BAD UDP")
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return dst, pc.vld.ErrPop()
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}
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ufrm.CRCWriteIPv4(&crc)
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wantSum := crc.Sum16()
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gotSum := ufrm.CRC()
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if wantSum != gotSum {
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protoErrs = append(protoErrs, &crcError16{protocol: "ipv4+udp", want: wantSum, got: gotSum})
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}
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}
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}
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return pc.captureIPProto(proto, dst, pkt, end, protoErrs...)
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}
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func (pc *PacketBreakdown) captureIPProto(proto lneto.IPProto, dst []Frame, pkt []byte, bitOffset int, ipProtoErrs ...error) (_ []Frame, err error) {
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nextFrame := len(dst)
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switch proto {
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case lneto.IPProtoTCP:
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dst, err = pc.CaptureTCP(dst, pkt, bitOffset)
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case lneto.IPProtoUDP:
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dst, err = pc.CaptureUDP(dst, pkt, bitOffset)
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case lneto.IPProtoUDPLite:
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dst, err = pc.CaptureUDP(dst, pkt, bitOffset)
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if len(dst) > nextFrame {
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dst[nextFrame].Protocol = lneto.IPProtoUDPLite
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}
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default:
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dst = append(dst, remainingFrameInfo(proto, 0, bitOffset, octet*len(pkt)))
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}
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if len(ipProtoErrs) > 0 && len(dst) > nextFrame {
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dst[nextFrame].Errors = append(dst[nextFrame].Errors, ipProtoErrs...)
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}
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return dst, err
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}
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func (pc *PacketBreakdown) CaptureTCP(dst []Frame, pkt []byte, bitOffset int) ([]Frame, error) {
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if bitOffset%8 != 0 {
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return dst, errors.New("TCP must be parsed at byte boundary")
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}
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tfrm, err := tcp.NewFrame(pkt[bitOffset/8:])
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if err != nil {
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return dst, err
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}
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tfrm.ValidateSize(pc.validator())
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if pc.validator().HasError() {
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return dst, pc.validator().ErrPop()
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}
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end := bitOffset + octet*tfrm.HeaderLength()
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finfo := Frame{
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Protocol: lneto.IPProtoTCP,
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PacketBitOffset: bitOffset,
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}
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finfo.Fields = append(finfo.Fields, baseTCPFields[:]...)
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options := tfrm.Options()
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if len(options) > 0 {
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finfo.Fields = append(finfo.Fields, FrameField{
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Class: FieldClassOptions,
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FrameBitOffset: 20 * octet,
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BitLength: octet * len(options),
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})
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}
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dst = append(dst, finfo)
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payload := tfrm.Payload()
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if len(payload) > 0 {
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dst, err = pc.CaptureHTTP(dst, pkt, end)
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if err != nil {
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dst = append(dst, remainingFrameInfo(unknownPayloadProto, FieldClassPayload, end, octet*len(pkt)))
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}
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}
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return dst, nil
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}
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// func (pc *PacketBreakdown) CaptureDHCPv4(dst []Frame, pkt []byte, bitOffset int) ([]Frame, error) {
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// }
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func (pc *PacketBreakdown) CaptureUDP(dst []Frame, pkt []byte, bitOffset int) ([]Frame, error) {
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if bitOffset%8 != 0 {
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return dst, errors.New("UDP must be parsed at byte boundary")
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}
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ufrm, err := udp.NewFrame(pkt[bitOffset/8:])
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if err != nil {
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return dst, err
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}
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ufrm.ValidateSize(pc.validator())
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if pc.validator().HasError() {
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return dst, pc.validator().ErrPop()
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}
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finfo := Frame{
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Protocol: lneto.IPProtoUDP,
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PacketBitOffset: bitOffset,
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}
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finfo.Fields = append(finfo.Fields, baseUDPFields[:]...)
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dst = append(dst, finfo)
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end := bitOffset + 8*octet
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payload := ufrm.Payload()
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dstport := ufrm.DestinationPort()
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srcport := ufrm.SourcePort()
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if dhcpv4.PayloadIsDHCPv4(payload) {
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dst, err = pc.CaptureDHCPv4(dst, pkt, end)
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} else if dstport == dns.ServerPort || srcport == dns.ServerPort {
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dst, err = pc.CaptureDNS(dst, pkt, end)
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} else if dstport == ntp.ServerPort || srcport == ntp.ServerPort {
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dst, err = pc.CaptureNTP(dst, pkt, end)
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}
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if err != nil {
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dst = append(dst, remainingFrameInfo(unknownPayloadProto, FieldClassPayload, end, octet*len(pkt)))
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}
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return dst, nil
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}
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func (pc *PacketBreakdown) CaptureDNS(dst []Frame, pkt []byte, bitOffset int) ([]Frame, error) {
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if bitOffset%8 != 0 {
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return nil, errors.New("DNS must be parsed at byte boundary")
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}
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dnsData := pkt[bitOffset/8:]
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pc.dmsg.LimitResourceDecoding(20, 20, 20, 20)
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off, incomplete, err := pc.dmsg.Decode(dnsData)
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if err != nil && !incomplete {
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return dst, err
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}
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finfo := Frame{
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Protocol: "DNS",
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PacketBitOffset: bitOffset,
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}
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if incomplete {
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finfo.Errors = append(finfo.Errors, errors.New("pcap: could not parse all DNS resources; add higher limit"))
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}
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finfo.Fields = append(finfo.Fields, FrameField{
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Name: "Data",
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FrameBitOffset: 0,
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BitLength: int(off) * octet,
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})
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dst = append(dst, finfo)
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return dst, nil
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}
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func (pc *PacketBreakdown) CaptureNTP(dst []Frame, pkt []byte, bitOffset int) ([]Frame, error) {
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if bitOffset%8 != 0 {
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return nil, errors.New("NTP must be parsed at byte boundary")
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}
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ntpData := pkt[bitOffset/8:]
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_, err := ntp.NewFrame(ntpData)
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if err != nil {
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return dst, err
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}
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finfo := Frame{
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Protocol: "NTP",
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PacketBitOffset: bitOffset,
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}
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finfo.Fields = append(finfo.Fields, baseNTPFields[:]...)
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dst = append(dst, finfo)
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return dst, nil
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}
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func (pc *PacketBreakdown) CaptureDHCPv4(dst []Frame, pkt []byte, bitOffset int) ([]Frame, error) {
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if bitOffset%8 != 0 {
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return nil, errors.New("DHCP must be parsed at byte boundary")
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}
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dhcpData := pkt[bitOffset/8:]
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dfrm, err := dhcpv4.NewFrame(dhcpData)
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if err != nil {
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return nil, err
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}
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finfo := Frame{
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Protocol: "DHCPv4",
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PacketBitOffset: bitOffset,
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}
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magic := dfrm.MagicCookie()
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if magic != dhcpv4.MagicCookie {
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finfo.Errors = append(finfo.Errors, errors.New("incorrect DHCPv4 magic cookie"))
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}
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finfo.Fields = append(finfo.Fields, baseDHCPv4Fields[:]...)
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options := dfrm.OptionsPayload()
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if len(options) > 0 {
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err = dfrm.ForEachOption(func(optoff int, op dhcpv4.OptNum, data []byte) error {
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finfo.Fields = append(finfo.Fields, FrameField{
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Name: op.String(),
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Class: FieldClassOptions,
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FrameBitOffset: optoff * octet,
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BitLength: (2 + len(data)) * octet,
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})
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return nil
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})
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if err != nil {
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finfo.Errors = append(finfo.Errors, err)
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}
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}
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dst = append(dst, finfo)
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return dst, nil
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}
|
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func (pc *PacketBreakdown) CaptureHTTP(dst []Frame, pkt []byte, bitOffset int) ([]Frame, error) {
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const httpProtocol = "HTTP"
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if bitOffset%8 != 0 {
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return nil, errors.New("HTTP must be parsed at byte boundary")
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}
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const asResponse = true
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const asRequest = false
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httpData := pkt[bitOffset/8:]
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pc.hdr.Reset(httpData)
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err := pc.hdr.Parse(asResponse)
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if err != nil {
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pc.hdr.Reset(httpData)
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err = pc.hdr.Parse(asRequest) // try as request.
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}
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if err != nil {
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return dst, err
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}
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hdrLen := pc.hdr.BufferParsed()
|
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body, _ := pc.hdr.Body()
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dst = append(dst, Frame{
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Protocol: httpProtocol,
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PacketBitOffset: bitOffset,
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Fields: []FrameField{
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{
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Name: "HTTP Header",
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Class: FieldClassText,
|
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FrameBitOffset: 0,
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BitLength: hdrLen * octet,
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},
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{
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Class: FieldClassPayload,
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FrameBitOffset: hdrLen * octet,
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BitLength: len(body) * octet,
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},
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},
|
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})
|
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return dst, err
|
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}
|
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|
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func (pc *PacketBreakdown) validator() *lneto.Validator {
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return &pc.vld
|
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}
|
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|
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type FrameField struct {
|
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Name string
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Class FieldClass
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FrameBitOffset int
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BitLength int
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SubFields []FrameField
|
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RightAligned bool
|
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}
|
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|
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type Frame struct {
|
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Protocol any
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Fields []FrameField
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PacketBitOffset int
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Errors []error
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}
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|
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// FieldByClass gets the frame field index with the argument FieldClass Class field set.
|
|
// If there are multiple fields with same class it will get the one with empty name.
|
|
// If there are multiple fields with same class and none have empty name then it will return an error.
|
|
func (frm Frame) FieldByClass(c FieldClass) (int, error) {
|
|
Nfields := len(frm.Fields)
|
|
selected := -1
|
|
multiple := false
|
|
for i := range Nfields {
|
|
field := &frm.Fields[i]
|
|
if field.Class != c {
|
|
continue
|
|
}
|
|
if field.Name == "" { // Prioritize "canonical" fields with no name.
|
|
if selected >= 0 && frm.Fields[selected].Name == "" {
|
|
return -1, errors.New("multiple class fields with no name")
|
|
}
|
|
selected = i
|
|
} else if selected >= 0 {
|
|
multiple = true
|
|
} else {
|
|
selected = i
|
|
}
|
|
}
|
|
if selected < 0 {
|
|
return -1, errors.New("field by class not found")
|
|
}
|
|
if multiple && frm.Fields[selected].Name != "" {
|
|
return -1, errors.New("multiple classes found and none have empty name")
|
|
}
|
|
return selected, nil
|
|
}
|
|
|
|
// FieldAsUint evaluates the field as a 64-bit integer.
|
|
func (frm Frame) FieldAsUint(fieldIdx int, pkt []byte) (uint64, error) {
|
|
const badUint64 = math.MaxUint64
|
|
if fieldIdx < 0 || fieldIdx >= len(frm.Fields) {
|
|
return badUint64, errors.New("invalid field index")
|
|
}
|
|
field := frm.Fields[fieldIdx]
|
|
octets := (field.BitLength + 7) / 8
|
|
if octets > 8 {
|
|
return badUint64, errors.New("field too long to be represented by uint64")
|
|
}
|
|
var buf [8]byte
|
|
_, err := frm.AppendField(buf[8-octets:8-octets], fieldIdx, pkt)
|
|
if err != nil {
|
|
return badUint64, err
|
|
}
|
|
v := binary.BigEndian.Uint64(buf[:])
|
|
return v, nil
|
|
}
|
|
|
|
func (frm Frame) AppendField(dst []byte, fieldIdx int, pkt []byte) ([]byte, error) {
|
|
if fieldIdx < 0 || fieldIdx >= len(frm.Fields) {
|
|
return dst, errors.New("invalid field index")
|
|
}
|
|
field := frm.Fields[fieldIdx]
|
|
fieldBitStart := frm.PacketBitOffset + field.FrameBitOffset
|
|
fieldBitEnd := fieldBitStart + field.BitLength
|
|
octets := (field.BitLength + 7) / 8 // total octets needed to represent field.
|
|
octetsStart := fieldBitStart / 8
|
|
if octets+octetsStart > len(pkt) {
|
|
return dst, errors.New("buffer overflow")
|
|
}
|
|
firstBitOffset := fieldBitStart % 8
|
|
lastOctetExcessBits := fieldBitEnd % 8
|
|
if firstBitOffset == 0 {
|
|
if field.RightAligned {
|
|
return dst, errors.New("invalid right aligned set for fully aligned field")
|
|
}
|
|
// Optimized path: field starts at byte boundary.
|
|
dst = append(dst, pkt[octetsStart:octetsStart+octets]...)
|
|
if lastOctetExcessBits != 0 {
|
|
dst[len(dst)-1] >>= lastOctetExcessBits
|
|
}
|
|
return dst, nil
|
|
}
|
|
|
|
mask := byte(1<<firstBitOffset) - 1
|
|
if field.RightAligned {
|
|
if lastOctetExcessBits == 0 {
|
|
// Right aligned with no loose trailing bits. i.e: TCP flags.
|
|
dst = append(dst, pkt[octetsStart]&mask)
|
|
dst = append(dst, pkt[octetsStart+1:octetsStart+octets]...)
|
|
return dst, nil
|
|
}
|
|
// Right aligned with trailing bits. i.e: ???
|
|
for i := 1; i < octets; i++ {
|
|
b := pkt[octetsStart+i] >> (8 - lastOctetExcessBits)
|
|
b |= pkt[octetsStart+i-1] & mask
|
|
dst = append(dst, b)
|
|
}
|
|
return dst, nil
|
|
}
|
|
|
|
// LEFT ALIGNED: TODO: test this.
|
|
for i := 0; i < octets-1; i++ {
|
|
// Append all octets except last one due to excess bits special handling.
|
|
b := pkt[i+octetsStart] & mask
|
|
b |= pkt[i+octetsStart+1] >> firstBitOffset
|
|
dst = append(dst, b)
|
|
}
|
|
lastOctet := pkt[octetsStart+octets-1] & mask
|
|
lastOctet >>= lastOctetExcessBits
|
|
dst = append(dst, lastOctet)
|
|
return dst, nil
|
|
}
|
|
|
|
func (frm Frame) String() string {
|
|
return string(frm.AppendString(nil))
|
|
}
|
|
|
|
func (frm Frame) AppendString(b []byte) []byte {
|
|
bitlen := frm.LenBits()
|
|
b = fmt.Appendf(b, "%s", frm.Protocol)
|
|
if bitlen%8 == 0 {
|
|
b = fmt.Appendf(b, " len=%d", bitlen/8)
|
|
} else {
|
|
b = fmt.Appendf(b, " bits=%d", bitlen)
|
|
}
|
|
iopt, err := frm.FieldByClass(FieldClassOptions)
|
|
if err == nil {
|
|
b = fmt.Appendf(b, " optlen=%d", (frm.Fields[iopt].BitLength+7)/8)
|
|
}
|
|
for _, err := range frm.Errors {
|
|
b = fmt.Appendf(b, " %s", err.Error())
|
|
}
|
|
return b
|
|
}
|
|
|
|
func (frm Frame) LenBits() (totalBitlen int) {
|
|
for i := range frm.Fields {
|
|
totalBitlen = max(totalBitlen, frm.Fields[i].FrameBitOffset+frm.Fields[i].BitLength)
|
|
}
|
|
return totalBitlen
|
|
}
|
|
|
|
func (ff FrameField) String() string {
|
|
if ff.Class == FieldClassPayload {
|
|
return fmt.Sprintf("Payload len=%d", ff.BitLength/8)
|
|
}
|
|
if ff.Name != "" {
|
|
return fmt.Sprintf("%s (%s)", ff.Name, ff.Class.String())
|
|
}
|
|
return ff.Class.String()
|
|
}
|
|
|
|
type FieldClass uint8
|
|
|
|
const (
|
|
fieldClassUndefined FieldClass = iota // undefined
|
|
FieldClassSrc // source
|
|
FieldClassDst // destination
|
|
FieldClassProto // protocol
|
|
FieldClassVersion // version
|
|
FieldClassType // type
|
|
FieldClassSize // field size
|
|
FieldClassFlags // flags
|
|
FieldClassID // identification
|
|
FieldClassChecksum // checksum
|
|
FieldClassOptions // options
|
|
FieldClassPayload // payload
|
|
FieldClassText // text
|
|
FieldClassAddress // address
|
|
)
|
|
|
|
const octet = 8
|
|
|
|
var baseEthernetFields = [...]FrameField{
|
|
{
|
|
Class: FieldClassDst,
|
|
FrameBitOffset: 0,
|
|
BitLength: 6 * octet,
|
|
},
|
|
{
|
|
Class: FieldClassSrc,
|
|
FrameBitOffset: 6 * octet,
|
|
BitLength: 6 * octet,
|
|
},
|
|
{
|
|
Class: FieldClassProto,
|
|
FrameBitOffset: 12 * octet,
|
|
BitLength: 2 * octet,
|
|
},
|
|
}
|
|
|
|
var baseARPFields = [...]FrameField{
|
|
{
|
|
Name: "Hardware type",
|
|
Class: FieldClassType,
|
|
FrameBitOffset: 0,
|
|
BitLength: 2 * octet,
|
|
},
|
|
{
|
|
Name: "Protocol type",
|
|
Class: FieldClassType,
|
|
FrameBitOffset: 2 * octet,
|
|
BitLength: 2 * octet,
|
|
},
|
|
{
|
|
Name: "Hardware size",
|
|
Class: FieldClassSize,
|
|
FrameBitOffset: 4 * octet,
|
|
BitLength: 1 * octet,
|
|
},
|
|
{
|
|
Name: "Protocol size",
|
|
Class: FieldClassSize,
|
|
FrameBitOffset: 5 * octet,
|
|
BitLength: 1 * octet,
|
|
},
|
|
{
|
|
Name: "Opcode",
|
|
Class: FieldClassType,
|
|
FrameBitOffset: 6 * octet,
|
|
BitLength: 2 * octet,
|
|
},
|
|
}
|
|
|
|
var baseIPv6Fields = [...]FrameField{
|
|
{
|
|
Class: FieldClassVersion,
|
|
FrameBitOffset: 0,
|
|
BitLength: 4,
|
|
},
|
|
{
|
|
Name: "Type of Service",
|
|
Class: FieldClassFlags,
|
|
FrameBitOffset: 4,
|
|
BitLength: 1 * octet,
|
|
RightAligned: true,
|
|
},
|
|
{
|
|
Name: "Flow Label",
|
|
Class: FieldClassID,
|
|
FrameBitOffset: 12,
|
|
BitLength: 20,
|
|
RightAligned: true,
|
|
},
|
|
{
|
|
Name: "Total Length",
|
|
Class: FieldClassSize,
|
|
FrameBitOffset: 4 * octet,
|
|
BitLength: 2 * octet,
|
|
},
|
|
{
|
|
Name: "Next Header",
|
|
Class: 0,
|
|
FrameBitOffset: 6 * octet,
|
|
BitLength: 1 * octet,
|
|
},
|
|
{
|
|
Name: "Hop Limit",
|
|
Class: 0,
|
|
FrameBitOffset: 7 * octet,
|
|
BitLength: 1 * octet,
|
|
},
|
|
{
|
|
Class: FieldClassSrc,
|
|
FrameBitOffset: 8 * octet,
|
|
BitLength: 16 * octet,
|
|
},
|
|
{
|
|
Class: FieldClassSrc,
|
|
FrameBitOffset: 24 * octet,
|
|
BitLength: 16 * octet,
|
|
},
|
|
}
|
|
|
|
var baseIPv4Fields = [...]FrameField{
|
|
{
|
|
Class: FieldClassVersion,
|
|
FrameBitOffset: 0,
|
|
BitLength: 4,
|
|
},
|
|
{
|
|
Name: "Header Length",
|
|
Class: FieldClassSize,
|
|
FrameBitOffset: 4,
|
|
BitLength: 4,
|
|
},
|
|
{
|
|
Name: "Type of Service",
|
|
Class: FieldClassFlags,
|
|
FrameBitOffset: 1 * octet,
|
|
BitLength: 1 * octet,
|
|
},
|
|
{
|
|
Name: "Total Length",
|
|
Class: FieldClassSize,
|
|
FrameBitOffset: 2 * octet,
|
|
BitLength: 2 * octet,
|
|
},
|
|
{
|
|
Class: FieldClassID,
|
|
FrameBitOffset: 4 * octet,
|
|
BitLength: 2 * octet,
|
|
},
|
|
{
|
|
Class: FieldClassID,
|
|
FrameBitOffset: 4 * octet,
|
|
BitLength: 2 * octet,
|
|
},
|
|
{
|
|
Class: FieldClassFlags,
|
|
FrameBitOffset: 6 * octet,
|
|
BitLength: 2 * octet,
|
|
},
|
|
{
|
|
Name: "Time to live",
|
|
FrameBitOffset: 8 * octet,
|
|
BitLength: 1 * octet,
|
|
},
|
|
{
|
|
Class: FieldClassProto,
|
|
FrameBitOffset: 9 * octet,
|
|
BitLength: 1 * octet,
|
|
},
|
|
{
|
|
Class: FieldClassChecksum,
|
|
FrameBitOffset: 10 * octet,
|
|
BitLength: 2 * octet,
|
|
},
|
|
{
|
|
Class: FieldClassSrc,
|
|
FrameBitOffset: 12 * octet,
|
|
BitLength: 4 * octet,
|
|
},
|
|
{
|
|
Class: FieldClassDst,
|
|
FrameBitOffset: 16 * octet,
|
|
BitLength: 4 * octet,
|
|
},
|
|
}
|
|
|
|
var baseTCPFields = [...]FrameField{
|
|
{
|
|
Name: "Source port",
|
|
Class: FieldClassSrc,
|
|
FrameBitOffset: 0,
|
|
BitLength: 2 * octet,
|
|
},
|
|
{
|
|
Name: "Destination port",
|
|
Class: FieldClassDst,
|
|
FrameBitOffset: 2 * octet,
|
|
BitLength: 2 * octet,
|
|
},
|
|
{
|
|
Name: "Sequence number",
|
|
Class: FieldClassID,
|
|
FrameBitOffset: 4 * octet,
|
|
BitLength: 4 * octet,
|
|
},
|
|
{
|
|
Name: "Acknowledgement number",
|
|
Class: FieldClassID,
|
|
FrameBitOffset: 8 * octet,
|
|
BitLength: 4 * octet,
|
|
},
|
|
{
|
|
Name: "Header length",
|
|
Class: FieldClassSize,
|
|
FrameBitOffset: 12 * octet,
|
|
BitLength: 4,
|
|
},
|
|
{
|
|
Class: FieldClassFlags,
|
|
FrameBitOffset: 12*octet + 4,
|
|
BitLength: 12,
|
|
RightAligned: true,
|
|
},
|
|
{
|
|
Name: "Window",
|
|
Class: 0,
|
|
FrameBitOffset: 14 * octet,
|
|
BitLength: 2 * octet,
|
|
},
|
|
{
|
|
Class: FieldClassChecksum,
|
|
FrameBitOffset: 16 * octet,
|
|
BitLength: 2 * octet,
|
|
},
|
|
{
|
|
Name: "Urgent pointer",
|
|
Class: 0,
|
|
FrameBitOffset: 18 * octet,
|
|
BitLength: 2 * octet,
|
|
},
|
|
}
|
|
|
|
var baseUDPFields = [...]FrameField{
|
|
{
|
|
Name: "Source port",
|
|
Class: FieldClassSrc,
|
|
FrameBitOffset: 0,
|
|
BitLength: 2 * octet,
|
|
},
|
|
{
|
|
Name: "Destination port",
|
|
Class: FieldClassDst,
|
|
FrameBitOffset: 2 * octet,
|
|
BitLength: 2 * octet,
|
|
},
|
|
{
|
|
Class: FieldClassSize,
|
|
FrameBitOffset: 4 * octet,
|
|
BitLength: 2 * octet,
|
|
},
|
|
{
|
|
Class: FieldClassChecksum,
|
|
FrameBitOffset: 6 * octet,
|
|
BitLength: 2 * octet,
|
|
},
|
|
}
|
|
|
|
var baseDHCPv4Fields = [...]FrameField{
|
|
{
|
|
Name: "Opcode",
|
|
Class: FieldClassType,
|
|
FrameBitOffset: 0,
|
|
BitLength: 1 * octet,
|
|
},
|
|
{
|
|
Name: "Hardware Address Type",
|
|
Class: FieldClassProto,
|
|
FrameBitOffset: 1 * octet,
|
|
BitLength: 1 * octet,
|
|
},
|
|
{
|
|
Name: "Hardware Address Length",
|
|
Class: FieldClassSize,
|
|
FrameBitOffset: 2 * octet,
|
|
BitLength: 1 * octet,
|
|
},
|
|
{
|
|
Name: "Hops",
|
|
Class: fieldClassUndefined,
|
|
FrameBitOffset: 3 * octet,
|
|
BitLength: 1 * octet,
|
|
},
|
|
{
|
|
Name: "Transaction ID",
|
|
Class: FieldClassID,
|
|
FrameBitOffset: 4 * octet,
|
|
BitLength: 4 * octet,
|
|
},
|
|
{
|
|
Name: "Start Time",
|
|
Class: fieldClassUndefined,
|
|
FrameBitOffset: 8 * octet,
|
|
BitLength: 2 * octet,
|
|
},
|
|
{
|
|
Name: "Flags",
|
|
Class: FieldClassFlags,
|
|
FrameBitOffset: 10 * octet,
|
|
BitLength: 2 * octet,
|
|
},
|
|
{
|
|
Name: "Client Address",
|
|
Class: FieldClassAddress,
|
|
FrameBitOffset: 12 * octet,
|
|
BitLength: 4 * octet,
|
|
},
|
|
{
|
|
Name: "Offered Address",
|
|
Class: FieldClassAddress,
|
|
FrameBitOffset: 16 * octet,
|
|
BitLength: 4 * octet,
|
|
},
|
|
{
|
|
Name: "Server Next Address",
|
|
Class: FieldClassAddress,
|
|
FrameBitOffset: 20 * octet,
|
|
BitLength: 4 * octet,
|
|
},
|
|
{
|
|
Name: "Relay Agent Address",
|
|
Class: FieldClassAddress,
|
|
FrameBitOffset: 24 * octet,
|
|
BitLength: 4 * octet,
|
|
},
|
|
{
|
|
Name: "Client Hardware Address",
|
|
Class: FieldClassAddress,
|
|
FrameBitOffset: 28 * octet,
|
|
BitLength: 16 * octet,
|
|
},
|
|
{
|
|
Name: "BOOTP",
|
|
Class: FieldClassAddress,
|
|
FrameBitOffset: (28 + 16) * octet,
|
|
BitLength: (dhcpv4.OptionsOffset - (28 + 16)) * octet,
|
|
},
|
|
}
|
|
|
|
var baseNTPFields = [...]FrameField{
|
|
{
|
|
Name: "Mode",
|
|
Class: FieldClassType,
|
|
FrameBitOffset: 0,
|
|
BitLength: 3,
|
|
},
|
|
{
|
|
Class: FieldClassVersion,
|
|
FrameBitOffset: 3,
|
|
BitLength: 2,
|
|
},
|
|
{
|
|
Name: "Leap Indicator",
|
|
Class: fieldClassUndefined,
|
|
FrameBitOffset: 5,
|
|
BitLength: 3,
|
|
},
|
|
{
|
|
Name: "Stratum",
|
|
Class: fieldClassUndefined,
|
|
FrameBitOffset: 1 * octet,
|
|
BitLength: 1 * octet,
|
|
},
|
|
{
|
|
Name: "Poll",
|
|
Class: fieldClassUndefined,
|
|
FrameBitOffset: 2 * octet,
|
|
BitLength: 1 * octet,
|
|
},
|
|
{
|
|
Name: "System Precision",
|
|
Class: fieldClassUndefined,
|
|
FrameBitOffset: 3 * octet,
|
|
BitLength: 1 * octet,
|
|
},
|
|
{
|
|
Name: "Root Delay",
|
|
Class: fieldClassUndefined,
|
|
FrameBitOffset: 4 * octet,
|
|
BitLength: 4 * octet,
|
|
},
|
|
{
|
|
Name: "Root Dispersion",
|
|
Class: fieldClassUndefined,
|
|
FrameBitOffset: 8 * octet,
|
|
BitLength: 4 * octet,
|
|
},
|
|
{
|
|
Name: "Reference ID",
|
|
Class: FieldClassText,
|
|
FrameBitOffset: 12 * octet,
|
|
BitLength: 4 * octet,
|
|
},
|
|
{
|
|
Name: "Reference Time",
|
|
Class: FieldClassText,
|
|
FrameBitOffset: 16 * octet,
|
|
BitLength: 8 * octet,
|
|
},
|
|
{
|
|
Name: "Origin Time",
|
|
Class: FieldClassText,
|
|
FrameBitOffset: 24 * octet,
|
|
BitLength: 8 * octet,
|
|
},
|
|
{
|
|
Name: "Receive Time",
|
|
Class: FieldClassText,
|
|
FrameBitOffset: 32 * octet,
|
|
BitLength: 8 * octet,
|
|
},
|
|
{
|
|
Name: "Transit Time",
|
|
Class: FieldClassText,
|
|
FrameBitOffset: 40 * octet,
|
|
BitLength: 8 * octet,
|
|
},
|
|
}
|
|
|
|
func remainingFrameInfo(proto any, class FieldClass, pktBitOffset, pktBitLen int) Frame {
|
|
return Frame{
|
|
Protocol: proto,
|
|
PacketBitOffset: pktBitOffset,
|
|
Fields: []FrameField{
|
|
{
|
|
Class: class,
|
|
BitLength: pktBitLen - pktBitOffset,
|
|
}},
|
|
}
|
|
}
|
|
|
|
type crcError16 struct {
|
|
protocol string
|
|
want uint16
|
|
got uint16
|
|
}
|
|
|
|
func (cerr *crcError16) Error() string {
|
|
return fmt.Sprintf("%s:incorrect checksum. want 0x%x, got 0x%x", cerr.protocol, cerr.want, cerr.got)
|
|
}
|