From 3f1edad4e6ba0a7876750aea55507fae14d8badf Mon Sep 17 00:00:00 2001 From: Milan Lenco Date: Wed, 11 Oct 2017 16:40:58 +0200 Subject: ODPM 266: Go-libmemif + 2 examples. Change-Id: Icdb9b9eb2314eff6c96afe7996fcf2728291de4a Signed-off-by: Milan Lenco --- vendor/github.com/google/gopacket/layers/tcp.go | 327 ++++++++++++++++++++++++ 1 file changed, 327 insertions(+) create mode 100644 vendor/github.com/google/gopacket/layers/tcp.go (limited to 'vendor/github.com/google/gopacket/layers/tcp.go') diff --git a/vendor/github.com/google/gopacket/layers/tcp.go b/vendor/github.com/google/gopacket/layers/tcp.go new file mode 100644 index 0000000..fb731da --- /dev/null +++ b/vendor/github.com/google/gopacket/layers/tcp.go @@ -0,0 +1,327 @@ +// Copyright 2012 Google, Inc. All rights reserved. +// Copyright 2009-2011 Andreas Krennmair. All rights reserved. +// +// Use of this source code is governed by a BSD-style license +// that can be found in the LICENSE file in the root of the source +// tree. + +package layers + +import ( + "encoding/binary" + "encoding/hex" + "errors" + "fmt" + + "github.com/google/gopacket" +) + +// TCP is the layer for TCP headers. +type TCP struct { + BaseLayer + SrcPort, DstPort TCPPort + Seq uint32 + Ack uint32 + DataOffset uint8 + FIN, SYN, RST, PSH, ACK, URG, ECE, CWR, NS bool + Window uint16 + Checksum uint16 + Urgent uint16 + sPort, dPort []byte + Options []TCPOption + Padding []byte + opts [4]TCPOption + tcpipchecksum +} + +// TCPOptionKind represents a TCP option code. +type TCPOptionKind uint8 + +const ( + TCPOptionKindEndList = 0 + TCPOptionKindNop = 1 + TCPOptionKindMSS = 2 // len = 4 + TCPOptionKindWindowScale = 3 // len = 3 + TCPOptionKindSACKPermitted = 4 // len = 2 + TCPOptionKindSACK = 5 // len = n + TCPOptionKindEcho = 6 // len = 6, obsolete + TCPOptionKindEchoReply = 7 // len = 6, obsolete + TCPOptionKindTimestamps = 8 // len = 10 + TCPOptionKindPartialOrderConnectionPermitted = 9 // len = 2, obsolete + TCPOptionKindPartialOrderServiceProfile = 10 // len = 3, obsolete + TCPOptionKindCC = 11 // obsolete + TCPOptionKindCCNew = 12 // obsolete + TCPOptionKindCCEcho = 13 // obsolete + TCPOptionKindAltChecksum = 14 // len = 3, obsolete + TCPOptionKindAltChecksumData = 15 // len = n, obsolete +) + +func (k TCPOptionKind) String() string { + switch k { + case TCPOptionKindEndList: + return "EndList" + case TCPOptionKindNop: + return "NOP" + case TCPOptionKindMSS: + return "MSS" + case TCPOptionKindWindowScale: + return "WindowScale" + case TCPOptionKindSACKPermitted: + return "SACKPermitted" + case TCPOptionKindSACK: + return "SACK" + case TCPOptionKindEcho: + return "Echo" + case TCPOptionKindEchoReply: + return "EchoReply" + case TCPOptionKindTimestamps: + return "Timestamps" + case TCPOptionKindPartialOrderConnectionPermitted: + return "PartialOrderConnectionPermitted" + case TCPOptionKindPartialOrderServiceProfile: + return "PartialOrderServiceProfile" + case TCPOptionKindCC: + return "CC" + case TCPOptionKindCCNew: + return "CCNew" + case TCPOptionKindCCEcho: + return "CCEcho" + case TCPOptionKindAltChecksum: + return "AltChecksum" + case TCPOptionKindAltChecksumData: + return "AltChecksumData" + default: + return fmt.Sprintf("Unknown(%d)", k) + } +} + +type TCPOption struct { + OptionType TCPOptionKind + OptionLength uint8 + OptionData []byte +} + +func (t TCPOption) String() string { + hd := hex.EncodeToString(t.OptionData) + if len(hd) > 0 { + hd = " 0x" + hd + } + switch t.OptionType { + case TCPOptionKindMSS: + return fmt.Sprintf("TCPOption(%s:%v%s)", + t.OptionType, + binary.BigEndian.Uint16(t.OptionData), + hd) + + case TCPOptionKindTimestamps: + if len(t.OptionData) == 8 { + return fmt.Sprintf("TCPOption(%s:%v/%v%s)", + t.OptionType, + binary.BigEndian.Uint32(t.OptionData[:4]), + binary.BigEndian.Uint32(t.OptionData[4:8]), + hd) + } + } + return fmt.Sprintf("TCPOption(%s:%s)", t.OptionType, hd) +} + +// LayerType returns gopacket.LayerTypeTCP +func (t *TCP) LayerType() gopacket.LayerType { return LayerTypeTCP } + +// SerializeTo writes the serialized form of this layer into the +// SerializationBuffer, implementing gopacket.SerializableLayer. +// See the docs for gopacket.SerializableLayer for more info. +func (t *TCP) SerializeTo(b gopacket.SerializeBuffer, opts gopacket.SerializeOptions) error { + var optionLength int + for _, o := range t.Options { + switch o.OptionType { + case 0, 1: + optionLength += 1 + default: + optionLength += 2 + len(o.OptionData) + } + } + if opts.FixLengths { + if rem := optionLength % 4; rem != 0 { + t.Padding = lotsOfZeros[:4-rem] + } + t.DataOffset = uint8((len(t.Padding) + optionLength + 20) / 4) + } + bytes, err := b.PrependBytes(20 + optionLength + len(t.Padding)) + if err != nil { + return err + } + binary.BigEndian.PutUint16(bytes, uint16(t.SrcPort)) + binary.BigEndian.PutUint16(bytes[2:], uint16(t.DstPort)) + binary.BigEndian.PutUint32(bytes[4:], t.Seq) + binary.BigEndian.PutUint32(bytes[8:], t.Ack) + binary.BigEndian.PutUint16(bytes[12:], t.flagsAndOffset()) + binary.BigEndian.PutUint16(bytes[14:], t.Window) + binary.BigEndian.PutUint16(bytes[18:], t.Urgent) + start := 20 + for _, o := range t.Options { + bytes[start] = byte(o.OptionType) + switch o.OptionType { + case 0, 1: + start++ + default: + if opts.FixLengths { + o.OptionLength = uint8(len(o.OptionData) + 2) + } + bytes[start+1] = o.OptionLength + copy(bytes[start+2:start+len(o.OptionData)+2], o.OptionData) + start += int(o.OptionLength) + } + } + copy(bytes[start:], t.Padding) + if opts.ComputeChecksums { + // zero out checksum bytes in current serialization. + bytes[16] = 0 + bytes[17] = 0 + csum, err := t.computeChecksum(b.Bytes(), IPProtocolTCP) + if err != nil { + return err + } + t.Checksum = csum + } + binary.BigEndian.PutUint16(bytes[16:], t.Checksum) + return nil +} + +func (t *TCP) ComputeChecksum() (uint16, error) { + return t.computeChecksum(append(t.Contents, t.Payload...), IPProtocolTCP) +} + +func (t *TCP) flagsAndOffset() uint16 { + f := uint16(t.DataOffset) << 12 + if t.FIN { + f |= 0x0001 + } + if t.SYN { + f |= 0x0002 + } + if t.RST { + f |= 0x0004 + } + if t.PSH { + f |= 0x0008 + } + if t.ACK { + f |= 0x0010 + } + if t.URG { + f |= 0x0020 + } + if t.ECE { + f |= 0x0040 + } + if t.CWR { + f |= 0x0080 + } + if t.NS { + f |= 0x0100 + } + return f +} + +func (tcp *TCP) DecodeFromBytes(data []byte, df gopacket.DecodeFeedback) error { + tcp.SrcPort = TCPPort(binary.BigEndian.Uint16(data[0:2])) + tcp.sPort = data[0:2] + tcp.DstPort = TCPPort(binary.BigEndian.Uint16(data[2:4])) + tcp.dPort = data[2:4] + tcp.Seq = binary.BigEndian.Uint32(data[4:8]) + tcp.Ack = binary.BigEndian.Uint32(data[8:12]) + tcp.DataOffset = data[12] >> 4 + tcp.FIN = data[13]&0x01 != 0 + tcp.SYN = data[13]&0x02 != 0 + tcp.RST = data[13]&0x04 != 0 + tcp.PSH = data[13]&0x08 != 0 + tcp.ACK = data[13]&0x10 != 0 + tcp.URG = data[13]&0x20 != 0 + tcp.ECE = data[13]&0x40 != 0 + tcp.CWR = data[13]&0x80 != 0 + tcp.NS = data[12]&0x01 != 0 + tcp.Window = binary.BigEndian.Uint16(data[14:16]) + tcp.Checksum = binary.BigEndian.Uint16(data[16:18]) + tcp.Urgent = binary.BigEndian.Uint16(data[18:20]) + tcp.Options = tcp.opts[:0] + if tcp.DataOffset < 5 { + return fmt.Errorf("Invalid TCP data offset %d < 5", tcp.DataOffset) + } + dataStart := int(tcp.DataOffset) * 4 + if dataStart > len(data) { + df.SetTruncated() + tcp.Payload = nil + tcp.Contents = data + return errors.New("TCP data offset greater than packet length") + } + tcp.Contents = data[:dataStart] + tcp.Payload = data[dataStart:] + // From here on, data points just to the header options. + data = data[20:dataStart] + for len(data) > 0 { + if tcp.Options == nil { + // Pre-allocate to avoid allocating a slice. + tcp.Options = tcp.opts[:0] + } + tcp.Options = append(tcp.Options, TCPOption{OptionType: TCPOptionKind(data[0])}) + opt := &tcp.Options[len(tcp.Options)-1] + switch opt.OptionType { + case TCPOptionKindEndList: // End of options + opt.OptionLength = 1 + tcp.Padding = data[1:] + break + case TCPOptionKindNop: // 1 byte padding + opt.OptionLength = 1 + default: + opt.OptionLength = data[1] + if opt.OptionLength < 2 { + return fmt.Errorf("Invalid TCP option length %d < 2", opt.OptionLength) + } else if int(opt.OptionLength) > len(data) { + return fmt.Errorf("Invalid TCP option length %d exceeds remaining %d bytes", opt.OptionLength, len(data)) + } + opt.OptionData = data[2:opt.OptionLength] + } + data = data[opt.OptionLength:] + } + return nil +} + +func (t *TCP) CanDecode() gopacket.LayerClass { + return LayerTypeTCP +} + +func (t *TCP) NextLayerType() gopacket.LayerType { + lt := t.DstPort.LayerType() + if lt == gopacket.LayerTypePayload { + lt = t.SrcPort.LayerType() + } + return lt +} + +func decodeTCP(data []byte, p gopacket.PacketBuilder) error { + tcp := &TCP{} + err := tcp.DecodeFromBytes(data, p) + p.AddLayer(tcp) + p.SetTransportLayer(tcp) + if err != nil { + return err + } + if p.DecodeOptions().DecodeStreamsAsDatagrams { + return p.NextDecoder(tcp.NextLayerType()) + } else { + return p.NextDecoder(gopacket.LayerTypePayload) + } +} + +func (t *TCP) TransportFlow() gopacket.Flow { + return gopacket.NewFlow(EndpointTCPPort, t.sPort, t.dPort) +} + +// For testing only +func (t *TCP) SetInternalPortsForTesting() { + t.sPort = make([]byte, 2) + t.dPort = make([]byte, 2) + binary.BigEndian.PutUint16(t.sPort, uint16(t.SrcPort)) + binary.BigEndian.PutUint16(t.dPort, uint16(t.DstPort)) +} -- cgit 1.2.3-korg