func decodeSCTPEmptyLayer(data []byte, p gopacket.PacketBuilder) error {
sc := &SCTPEmptyLayer{
SCTPChunk: decodeSCTPChunk(data),
}
p.AddLayer(sc)
return p.NextDecoder(gopacket.DecodeFunc(decodeWithSCTPChunkTypePrefix))
}
func decodeSCTPShutdown(data []byte, p gopacket.PacketBuilder) error {
sc := &SCTPShutdown{
SCTPChunk: decodeSCTPChunk(data),
CumulativeTSNAck: binary.BigEndian.Uint32(data[4:8]),
}
p.AddLayer(sc)
return p.NextDecoder(gopacket.DecodeFunc(decodeWithSCTPChunkTypePrefix))
}
func decodeSCTPCookieEcho(data []byte, p gopacket.PacketBuilder) error {
sc := &SCTPCookieEcho{
SCTPChunk: decodeSCTPChunk(data),
}
sc.Cookie = data[4:sc.Length]
p.AddLayer(sc)
return p.NextDecoder(gopacket.DecodeFunc(decodeWithSCTPChunkTypePrefix))
}
func decodeIPv6HopByHop(data []byte, p gopacket.PacketBuilder) error {
i := &IPv6HopByHop{}
err := i.DecodeFromBytes(data, p)
p.AddLayer(i)
if err != nil {
return err
}
return p.NextDecoder(i.NextHeader)
}
func decodeIPSecESP(data []byte, p gopacket.PacketBuilder) error {
i := &IPSecESP{
BaseLayer: BaseLayer{data, nil},
SPI: binary.BigEndian.Uint32(data[:4]),
Seq: binary.BigEndian.Uint32(data[4:8]),
Encrypted: data[8:],
}
p.AddLayer(i)
return nil
}
func decodeEthernetCTP(data []byte, p gopacket.PacketBuilder) error {
c := &EthernetCTP{
SkipCount: binary.LittleEndian.Uint16(data[:2]),
BaseLayer: BaseLayer{data[:2], data[2:]},
}
if c.SkipCount%2 != 0 {
return fmt.Errorf("EthernetCTP skip count is odd: %d", c.SkipCount)
}
p.AddLayer(c)
return p.NextDecoder(gopacket.DecodeFunc(decodeEthernetCTPFromFunctionType))
}
func decodeIPSecAH(data []byte, p gopacket.PacketBuilder) error {
i := &IPSecAH{
ipv6ExtensionBase: decodeIPv6ExtensionBase(data),
Reserved: binary.BigEndian.Uint16(data[2:4]),
SPI: binary.BigEndian.Uint32(data[4:8]),
Seq: binary.BigEndian.Uint32(data[8:12]),
}
i.AuthenticationData = i.Contents[12:]
p.AddLayer(i)
return p.NextDecoder(i.NextHeader)
}
func decodeMPLS(data []byte, p gopacket.PacketBuilder) error {
decoded := binary.BigEndian.Uint32(data[:4])
p.AddLayer(&MPLS{
Label: decoded >> 12,
TrafficClass: uint8(decoded>>9) & 0x7,
StackBottom: decoded&0x100 != 0,
TTL: uint8(decoded),
BaseLayer: BaseLayer{data[:4], data[4:]},
})
return p.NextDecoder(MPLSPayloadDecoder)
}
func decodingLayerDecoder(d layerDecodingLayer, data []byte, p gopacket.PacketBuilder) error {
err := d.DecodeFromBytes(data, p)
if err != nil {
return err
}
p.AddLayer(d)
next := d.NextLayerType()
if next == gopacket.LayerTypeZero {
return nil
}
return p.NextDecoder(next)
}
func decodeSNAP(data []byte, p gopacket.PacketBuilder) error {
s := &SNAP{
OrganizationalCode: data[:3],
Type: EthernetType(binary.BigEndian.Uint16(data[3:5])),
BaseLayer: BaseLayer{data[:5], data[5:]},
}
p.AddLayer(s)
// BUG(gconnell): When decoding SNAP, we treat the SNAP type as an Ethernet
// type. This may not actually be an ethernet type in all cases,
// depending on the organizational code. Right now, we don't check.
return p.NextDecoder(s.Type)
}
// decodePPPoE decodes the PPPoE header (see http://tools.ietf.org/html/rfc2516).
func decodePPPoE(data []byte, p gopacket.PacketBuilder) error {
pppoe := &PPPoE{
Version: data[0] >> 4,
Type: data[0] & 0x0F,
Code: PPPoECode(data[1]),
SessionId: binary.BigEndian.Uint16(data[2:4]),
Length: binary.BigEndian.Uint16(data[4:6]),
}
pppoe.BaseLayer = BaseLayer{data[:6], data[6 : 6+pppoe.Length]}
p.AddLayer(pppoe)
return p.NextDecoder(pppoe.Code)
}
func decodeIPv6Fragment(data []byte, p gopacket.PacketBuilder) error {
i := &IPv6Fragment{
BaseLayer: BaseLayer{data[:8], data[8:]},
NextHeader: IPProtocol(data[0]),
Reserved1: data[1],
FragmentOffset: binary.BigEndian.Uint16(data[2:4]) >> 3,
Reserved2: data[3] & 0x6 >> 1,
MoreFragments: data[3]&0x1 != 0,
Identification: binary.BigEndian.Uint32(data[4:8]),
}
p.AddLayer(i)
return p.NextDecoder(gopacket.DecodeFragment)
}
func decodeSCTPHeartbeat(data []byte, p gopacket.PacketBuilder) error {
sc := &SCTPHeartbeat{
SCTPChunk: decodeSCTPChunk(data),
}
paramData := data[4:sc.Length]
for len(paramData) > 0 {
p := SCTPHeartbeatParameter(decodeSCTPParameter(paramData))
paramData = paramData[p.ActualLength:]
sc.Parameters = append(sc.Parameters, p)
}
p.AddLayer(sc)
return p.NextDecoder(gopacket.DecodeFunc(decodeWithSCTPChunkTypePrefix))
}
func decodeIPv6Destination(data []byte, p gopacket.PacketBuilder) error {
i := &IPv6Destination{
ipv6ExtensionBase: decodeIPv6ExtensionBase(data),
// We guess we'll 1-2 options, one regular option at least, then maybe one
// padding option.
Options: make([]IPv6DestinationOption, 0, 2),
}
var opt *IPv6DestinationOption
for d := i.Contents[2:]; len(d) > 0; d = d[opt.ActualLength:] {
i.Options = append(i.Options, IPv6DestinationOption(decodeIPv6HeaderTLVOption(d)))
opt = &i.Options[len(i.Options)-1]
}
p.AddLayer(i)
return p.NextDecoder(i.NextHeader)
}
func decodeSCTPInit(data []byte, p gopacket.PacketBuilder) error {
sc := &SCTPInit{
SCTPChunk: decodeSCTPChunk(data),
InitiateTag: binary.BigEndian.Uint32(data[4:8]),
AdvertisedReceiverWindowCredit: binary.BigEndian.Uint32(data[8:12]),
OutboundStreams: binary.BigEndian.Uint16(data[12:14]),
InboundStreams: binary.BigEndian.Uint16(data[14:16]),
InitialTSN: binary.BigEndian.Uint32(data[16:20]),
}
paramData := data[20:sc.ActualLength]
for len(paramData) > 0 {
p := SCTPInitParameter(decodeSCTPParameter(paramData))
paramData = paramData[p.ActualLength:]
sc.Parameters = append(sc.Parameters, p)
}
p.AddLayer(sc)
return p.NextDecoder(gopacket.DecodeFunc(decodeWithSCTPChunkTypePrefix))
}
func decodeIPv6(data []byte, p gopacket.PacketBuilder) error {
ip6 := &IPv6{}
err := ip6.DecodeFromBytes(data, p)
p.AddLayer(ip6)
p.SetNetworkLayer(ip6)
if ip6.HopByHop != nil {
// TODO(gconnell): Since HopByHop is now an integral part of the IPv6
// layer, should it actually be added as its own layer? I'm leaning towards
// no.
p.AddLayer(ip6.HopByHop)
}
if err != nil {
return err
}
if ip6.HopByHop != nil {
return p.NextDecoder(ip6.HopByHop.NextHeader)
}
return p.NextDecoder(ip6.NextHeader)
}
func decodeCiscoDiscovery(data []byte, p gopacket.PacketBuilder) error {
c := &CiscoDiscovery{
Version: data[0],
TTL: data[1],
Checksum: binary.BigEndian.Uint16(data[2:4]),
}
if c.Version != 1 && c.Version != 2 {
return fmt.Errorf("Invalid CiscoDiscovery version number %d", c.Version)
}
var err error
c.Values, err = decodeCiscoDiscoveryTLVs(data[4:])
if err != nil {
return err
}
c.Contents = data[0:4]
c.Payload = data[4:]
p.AddLayer(c)
return p.NextDecoder(gopacket.DecodeFunc(decodeCiscoDiscoveryInfo))
}
func decodeIPv6Routing(data []byte, p gopacket.PacketBuilder) error {
i := &IPv6Routing{
ipv6ExtensionBase: decodeIPv6ExtensionBase(data),
RoutingType: data[2],
SegmentsLeft: data[3],
Reserved: data[4:8],
}
switch i.RoutingType {
case 0: // Source routing
if (len(data)-8)%16 != 0 {
return fmt.Errorf("Invalid IPv6 source routing, length of type 0 packet %d", len(data))
}
for d := i.Contents[8:]; len(d) >= 16; d = d[16:] {
i.SourceRoutingIPs = append(i.SourceRoutingIPs, net.IP(d[:16]))
}
}
p.AddLayer(i)
return p.NextDecoder(i.NextHeader)
}
func decodeLoopback(data []byte, p gopacket.PacketBuilder) error {
// The protocol could be either big-endian or little-endian, we're
// not sure. But we're PRETTY sure that the value is less than
// 256, so we can check the first two bytes.
var prot uint32
if data[0] == 0 && data[1] == 0 {
prot = binary.BigEndian.Uint32(data[:4])
} else {
prot = binary.LittleEndian.Uint32(data[:4])
}
if prot > 0xFF {
return fmt.Errorf("Invalid loopback protocol %q", data[:4])
}
l := &Loopback{
BaseLayer: BaseLayer{data[:4], data[4:]},
Family: ProtocolFamily(prot),
}
p.AddLayer(l)
return p.NextDecoder(l.Family)
}
func decodeSCTPChunkTypeUnknown(data []byte, p gopacket.PacketBuilder) error {
sc := &SCTPUnknownChunkType{SCTPChunk: decodeSCTPChunk(data)}
sc.bytes = data[:sc.ActualLength]
p.AddLayer(sc)
p.SetErrorLayer(sc)
return p.NextDecoder(gopacket.DecodeFunc(decodeWithSCTPChunkTypePrefix))
}
func decodeLinuxSLL(data []byte, p gopacket.PacketBuilder) error {
sll := &LinuxSLL{}
if err := sll.DecodeFromBytes(data, p); err != nil {
return err
}
p.AddLayer(sll)
p.SetLinkLayer(sll)
return p.NextDecoder(sll.EthernetType)
}
func decodeSCTPSack(data []byte, p gopacket.PacketBuilder) error {
sc := &SCTPSack{
SCTPChunk: decodeSCTPChunk(data),
CumulativeTSNAck: binary.BigEndian.Uint32(data[4:8]),
AdvertisedReceiverWindowCredit: binary.BigEndian.Uint32(data[8:12]),
NumGapACKs: binary.BigEndian.Uint16(data[12:14]),
NumDuplicateTSNs: binary.BigEndian.Uint16(data[14:16]),
}
// We maximize gapAcks and dupTSNs here so we're not allocating tons
// of memory based on a user-controlable field. Our maximums are not exact,
// but should give us sane defaults... we'll still hit slice boundaries and
// fail if the user-supplied values are too high (in the for loops below), but
// the amount of memory we'll have allocated because of that should be small
// (< sc.ActualLength)
gapAcks := sc.SCTPChunk.ActualLength / 2
dupTSNs := (sc.SCTPChunk.ActualLength - gapAcks*2) / 4
if gapAcks > int(sc.NumGapACKs) {
gapAcks = int(sc.NumGapACKs)
}
if dupTSNs > int(sc.NumDuplicateTSNs) {
dupTSNs = int(sc.NumDuplicateTSNs)
}
sc.GapACKs = make([]uint16, 0, gapAcks)
sc.DuplicateTSNs = make([]uint32, 0, dupTSNs)
bytesRemaining := data[16:]
for i := 0; i < int(sc.NumGapACKs); i++ {
sc.GapACKs = append(sc.GapACKs, binary.BigEndian.Uint16(bytesRemaining[:2]))
bytesRemaining = bytesRemaining[2:]
}
for i := 0; i < int(sc.NumDuplicateTSNs); i++ {
sc.DuplicateTSNs = append(sc.DuplicateTSNs, binary.BigEndian.Uint32(bytesRemaining[:4]))
bytesRemaining = bytesRemaining[4:]
}
p.AddLayer(sc)
return p.NextDecoder(gopacket.DecodeFunc(decodeWithSCTPChunkTypePrefix))
}
func decodeUDP(data []byte, p gopacket.PacketBuilder) error {
udp := &UDP{}
err := udp.DecodeFromBytes(data, p)
p.AddLayer(udp)
p.SetTransportLayer(udp)
if err != nil {
return err
}
return p.NextDecoder(gopacket.LayerTypePayload)
}
func decodeIPv4(data []byte, p gopacket.PacketBuilder) error {
ip := &IPv4{}
err := ip.DecodeFromBytes(data, p)
p.AddLayer(ip)
p.SetNetworkLayer(ip)
if err != nil {
return err
}
return p.NextDecoder(ip.NextLayerType())
}
func decodeEthernet(data []byte, p gopacket.PacketBuilder) error {
eth := &Ethernet{}
err := eth.DecodeFromBytes(data, p)
if err != nil {
return err
}
p.AddLayer(eth)
p.SetLinkLayer(eth)
return p.NextDecoder(eth.EthernetType)
}
func decodeFDDI(data []byte, p gopacket.PacketBuilder) error {
f := &FDDI{
FrameControl: FDDIFrameControl(data[0] & 0xF8),
Priority: data[0] & 0x07,
SrcMAC: net.HardwareAddr(data[1:7]),
DstMAC: net.HardwareAddr(data[7:13]),
BaseLayer: BaseLayer{data[:13], data[13:]},
}
p.SetLinkLayer(f)
p.AddLayer(f)
return p.NextDecoder(f.FrameControl)
}
func decodeSCTP(data []byte, p gopacket.PacketBuilder) error {
sctp := &SCTP{
SrcPort: SCTPPort(binary.BigEndian.Uint16(data[:2])),
sPort: data[:2],
DstPort: SCTPPort(binary.BigEndian.Uint16(data[2:4])),
dPort: data[2:4],
VerificationTag: binary.BigEndian.Uint32(data[4:8]),
Checksum: binary.BigEndian.Uint32(data[8:12]),
BaseLayer: BaseLayer{data[:12], data[12:]},
}
p.AddLayer(sctp)
p.SetTransportLayer(sctp)
return p.NextDecoder(sctpChunkTypePrefixDecoder)
}
func decodeRUDP(data []byte, p gopacket.PacketBuilder) error {
r := &RUDP{
SYN: data[0]&0x80 != 0,
ACK: data[0]&0x40 != 0,
EACK: data[0]&0x20 != 0,
RST: data[0]&0x10 != 0,
NUL: data[0]&0x08 != 0,
Version: data[0] & 0x3,
HeaderLength: data[1],
SrcPort: RUDPPort(data[2]),
DstPort: RUDPPort(data[3]),
DataLength: binary.BigEndian.Uint16(data[4:6]),
Seq: binary.BigEndian.Uint32(data[6:10]),
Ack: binary.BigEndian.Uint32(data[10:14]),
Checksum: binary.BigEndian.Uint32(data[14:18]),
}
if r.HeaderLength < 9 {
return fmt.Errorf("RUDP packet with too-short header length %d", r.HeaderLength)
}
hlen := int(r.HeaderLength) * 2
r.Contents = data[:hlen]
r.Payload = data[hlen : hlen+int(r.DataLength)]
r.VariableHeaderArea = data[18:hlen]
headerData := r.VariableHeaderArea
switch {
case r.SYN:
if len(headerData) != 6 {
return fmt.Errorf("RUDP packet invalid SYN header length: %d", len(headerData))
}
r.RUDPHeaderSYN = &RUDPHeaderSYN{
MaxOutstandingSegments: binary.BigEndian.Uint16(headerData[:2]),
MaxSegmentSize: binary.BigEndian.Uint16(headerData[2:4]),
OptionFlags: binary.BigEndian.Uint16(headerData[4:6]),
}
case r.EACK:
if len(headerData)%4 != 0 {
return fmt.Errorf("RUDP packet invalid EACK header length: %d", len(headerData))
}
r.RUDPHeaderEACK = &RUDPHeaderEACK{make([]uint32, len(headerData)/4)}
for i := 0; i < len(headerData); i += 4 {
r.SeqsReceivedOK[i/4] = binary.BigEndian.Uint32(headerData[i : i+4])
}
}
p.AddLayer(r)
p.SetTransportLayer(r)
return p.NextDecoder(gopacket.LayerTypePayload)
}
func decodeSCTPData(data []byte, p gopacket.PacketBuilder) error {
sc := &SCTPData{
SCTPChunk: decodeSCTPChunk(data),
Unordered: data[1]&0x4 != 0,
BeginFragment: data[1]&0x2 != 0,
EndFragment: data[1]&0x1 != 0,
TSN: binary.BigEndian.Uint32(data[4:8]),
StreamId: binary.BigEndian.Uint16(data[8:10]),
StreamSequence: binary.BigEndian.Uint16(data[10:12]),
PayloadProtocol: binary.BigEndian.Uint32(data[12:16]),
}
// Length is the length in bytes of the data, INCLUDING the 16-byte header.
sc.PayloadData = data[16:sc.Length]
p.AddLayer(sc)
p.SetApplicationLayer(sc)
return p.NextDecoder(gopacket.DecodeFunc(decodeWithSCTPChunkTypePrefix))
}
// decodeEthernetCTPFromFunctionType reads in the first 2 bytes to determine the EthernetCTP
// layer type to decode next, then decodes based on that.
func decodeEthernetCTPFromFunctionType(data []byte, p gopacket.PacketBuilder) error {
function := EthernetCTPFunction(binary.LittleEndian.Uint16(data[:2]))
switch function {
case EthernetCTPFunctionReply:
reply := &EthernetCTPReply{
Function: function,
ReceiptNumber: binary.LittleEndian.Uint16(data[2:4]),
Data: data[4:],
BaseLayer: BaseLayer{data, nil},
}
p.AddLayer(reply)
p.SetApplicationLayer(reply)
return nil
case EthernetCTPFunctionForwardData:
forward := &EthernetCTPForwardData{
Function: function,
ForwardAddress: data[2:8],
BaseLayer: BaseLayer{data[:8], data[8:]},
}
p.AddLayer(forward)
return p.NextDecoder(gopacket.DecodeFunc(decodeEthernetCTPFromFunctionType))
}
return fmt.Errorf("Unknown EthernetCTP function type %v", function)
}