1 files changed, 311 insertions, 0 deletions
diff --git a/vendor/github.com/google/gopacket/layers/ip4.go b/vendor/github.com/google/gopacket/layers/ip4.go
new file mode 100644
index 0000000..3f31b27
--- /dev/null
+++ b/vendor/github.com/google/gopacket/layers/ip4.go
@@ -0,0 +1,311 @@
+// 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"
+	"errors"
+	"fmt"
+	"net"
+	"strings"
+
+	"github.com/google/gopacket"
+)
+
+type IPv4Flag uint8
+
+const (
+	IPv4EvilBit       IPv4Flag = 1 << 2 // http://tools.ietf.org/html/rfc3514 ;)
+	IPv4DontFragment  IPv4Flag = 1 << 1
+	IPv4MoreFragments IPv4Flag = 1 << 0
+)
+
+func (f IPv4Flag) String() string {
+	var s []string
+	if f&IPv4EvilBit != 0 {
+		s = append(s, "Evil")
+	}
+	if f&IPv4DontFragment != 0 {
+		s = append(s, "DF")
+	}
+	if f&IPv4MoreFragments != 0 {
+		s = append(s, "MF")
+	}
+	return strings.Join(s, "|")
+}
+
+// IPv4 is the header of an IP packet.
+type IPv4 struct {
+	BaseLayer
+	Version    uint8
+	IHL        uint8
+	TOS        uint8
+	Length     uint16
+	Id         uint16
+	Flags      IPv4Flag
+	FragOffset uint16
+	TTL        uint8
+	Protocol   IPProtocol
+	Checksum   uint16
+	SrcIP      net.IP
+	DstIP      net.IP
+	Options    []IPv4Option
+	Padding    []byte
+}
+
+// LayerType returns LayerTypeIPv4
+func (i *IPv4) LayerType() gopacket.LayerType { return LayerTypeIPv4 }
+func (i *IPv4) NetworkFlow() gopacket.Flow {
+	return gopacket.NewFlow(EndpointIPv4, i.SrcIP, i.DstIP)
+}
+
+type IPv4Option struct {
+	OptionType   uint8
+	OptionLength uint8
+	OptionData   []byte
+}
+
+func (i IPv4Option) String() string {
+	return fmt.Sprintf("IPv4Option(%v:%v)", i.OptionType, i.OptionData)
+}
+
+// for the current ipv4 options, return the number of bytes (including
+// padding that the options used)
+func (ip *IPv4) getIPv4OptionSize() uint8 {
+	optionSize := uint8(0)
+	for _, opt := range ip.Options {
+		switch opt.OptionType {
+		case 0:
+			// this is the end of option lists
+			optionSize++
+		case 1:
+			// this is the padding
+			optionSize++
+		default:
+			optionSize += opt.OptionLength
+
+		}
+	}
+	// make sure the options are aligned to 32 bit boundary
+	if (optionSize % 4) != 0 {
+		optionSize += 4 - (optionSize % 4)
+	}
+	return optionSize
+}
+
+// SerializeTo writes the serialized form of this layer into the
+// SerializationBuffer, implementing gopacket.SerializableLayer.
+func (ip *IPv4) SerializeTo(b gopacket.SerializeBuffer, opts gopacket.SerializeOptions) error {
+	optionLength := ip.getIPv4OptionSize()
+	bytes, err := b.PrependBytes(20 + int(optionLength))
+	if err != nil {
+		return err
+	}
+	if opts.FixLengths {
+		ip.IHL = 5 + (optionLength / 4)
+		ip.Length = uint16(len(b.Bytes()))
+	}
+	bytes[0] = (ip.Version << 4) | ip.IHL
+	bytes[1] = ip.TOS
+	binary.BigEndian.PutUint16(bytes[2:], ip.Length)
+	binary.BigEndian.PutUint16(bytes[4:], ip.Id)
+	binary.BigEndian.PutUint16(bytes[6:], ip.flagsfrags())
+	bytes[8] = ip.TTL
+	bytes[9] = byte(ip.Protocol)
+	if err := ip.AddressTo4(); err != nil {
+		return err
+	}
+	copy(bytes[12:16], ip.SrcIP)
+	copy(bytes[16:20], ip.DstIP)
+
+	curLocation := 20
+	// Now, we will encode the options
+	for _, opt := range ip.Options {
+		switch opt.OptionType {
+		case 0:
+			// this is the end of option lists
+			bytes[curLocation] = 0
+			curLocation++
+		case 1:
+			// this is the padding
+			bytes[curLocation] = 1
+			curLocation++
+		default:
+			bytes[curLocation] = opt.OptionType
+			bytes[curLocation+1] = opt.OptionLength
+
+			// sanity checking to protect us from buffer overrun
+			if len(opt.OptionData) > int(opt.OptionLength-2) {
+				return errors.New("option length is smaller than length of option data")
+			}
+			copy(bytes[curLocation+2:curLocation+int(opt.OptionLength)], opt.OptionData)
+			curLocation += int(opt.OptionLength)
+		}
+	}
+
+	if opts.ComputeChecksums {
+		ip.Checksum = checksum(bytes)
+	}
+	binary.BigEndian.PutUint16(bytes[10:], ip.Checksum)
+	return nil
+}
+
+func checksum(bytes []byte) uint16 {
+	// Clear checksum bytes
+	bytes[10] = 0
+	bytes[11] = 0
+
+	// Compute checksum
+	var csum uint32
+	for i := 0; i < len(bytes); i += 2 {
+		csum += uint32(bytes[i]) << 8
+		csum += uint32(bytes[i+1])
+	}
+	for {
+		// Break when sum is less or equals to 0xFFFF
+		if csum <= 65535 {
+			break
+		}
+		// Add carry to the sum
+		csum = (csum >> 16) + uint32(uint16(csum))
+	}
+	// Flip all the bits
+	return ^uint16(csum)
+}
+
+func (ip *IPv4) flagsfrags() (ff uint16) {
+	ff |= uint16(ip.Flags) << 13
+	ff |= ip.FragOffset
+	return
+}
+
+// DecodeFromBytes decodes the given bytes into this layer.
+func (ip *IPv4) DecodeFromBytes(data []byte, df gopacket.DecodeFeedback) error {
+	flagsfrags := binary.BigEndian.Uint16(data[6:8])
+
+	ip.Version = uint8(data[0]) >> 4
+	ip.IHL = uint8(data[0]) & 0x0F
+	ip.TOS = data[1]
+	ip.Length = binary.BigEndian.Uint16(data[2:4])
+	ip.Id = binary.BigEndian.Uint16(data[4:6])
+	ip.Flags = IPv4Flag(flagsfrags >> 13)
+	ip.FragOffset = flagsfrags & 0x1FFF
+	ip.TTL = data[8]
+	ip.Protocol = IPProtocol(data[9])
+	ip.Checksum = binary.BigEndian.Uint16(data[10:12])
+	ip.SrcIP = data[12:16]
+	ip.DstIP = data[16:20]
+	ip.Options = ip.Options[:0]
+	// Set up an initial guess for contents/payload... we'll reset these soon.
+	ip.BaseLayer = BaseLayer{Contents: data}
+
+	// This code is added for the following enviroment:
+	// * Windows 10 with TSO option activated. ( tested on Hyper-V, RealTek ethernet driver )
+	if ip.Length == 0 {
+		// If using TSO(TCP Segmentation Offload), length is zero.
+		// The actual packet length is the length of data.
+		ip.Length = uint16(len(data))
+	}
+
+	if ip.Length < 20 {
+		return fmt.Errorf("Invalid (too small) IP length (%d < 20)", ip.Length)
+	} else if ip.IHL < 5 {
+		return fmt.Errorf("Invalid (too small) IP header length (%d < 5)", ip.IHL)
+	} else if int(ip.IHL*4) > int(ip.Length) {
+		return fmt.Errorf("Invalid IP header length > IP length (%d > %d)", ip.IHL, ip.Length)
+	}
+	if cmp := len(data) - int(ip.Length); cmp > 0 {
+		data = data[:ip.Length]
+	} else if cmp < 0 {
+		df.SetTruncated()
+		if int(ip.IHL)*4 > len(data) {
+			return errors.New("Not all IP header bytes available")
+		}
+	}
+	ip.Contents = data[:ip.IHL*4]
+	ip.Payload = data[ip.IHL*4:]
+	// From here on, data contains the header options.
+	data = data[20 : ip.IHL*4]
+	// Pull out IP options
+	for len(data) > 0 {
+		if ip.Options == nil {
+			// Pre-allocate to avoid growing the slice too much.
+			ip.Options = make([]IPv4Option, 0, 4)
+		}
+		opt := IPv4Option{OptionType: data[0]}
+		switch opt.OptionType {
+		case 0: // End of options
+			opt.OptionLength = 1
+			ip.Options = append(ip.Options, opt)
+			ip.Padding = data[1:]
+			break
+		case 1: // 1 byte padding
+			opt.OptionLength = 1
+		default:
+			opt.OptionLength = data[1]
+			opt.OptionData = data[2:opt.OptionLength]
+		}
+		if len(data) >= int(opt.OptionLength) {
+			data = data[opt.OptionLength:]
+		} else {
+			return fmt.Errorf("IP option length exceeds remaining IP header size, option type %v length %v", opt.OptionType, opt.OptionLength)
+		}
+		ip.Options = append(ip.Options, opt)
+	}
+	return nil
+}
+
+func (i *IPv4) CanDecode() gopacket.LayerClass {
+	return LayerTypeIPv4
+}
+
+func (i *IPv4) NextLayerType() gopacket.LayerType {
+	if i.Flags&IPv4MoreFragments != 0 || i.FragOffset != 0 {
+		return gopacket.LayerTypeFragment
+	}
+	return i.Protocol.LayerType()
+}
+
+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 checkIPv4Address(addr net.IP) (net.IP, error) {
+	if c := addr.To4(); c != nil {
+		return c, nil
+	}
+	if len(addr) == net.IPv6len {
+		return nil, errors.New("address is IPv6")
+	}
+	return nil, fmt.Errorf("wrong length of %d bytes instead of %d", len(addr), net.IPv4len)
+}
+
+func (ip *IPv4) AddressTo4() error {
+	var src, dst net.IP
+
+	if addr, err := checkIPv4Address(ip.SrcIP); err != nil {
+		return fmt.Errorf("Invalid source IPv4 address (%s)", err)
+	} else {
+		src = addr
+	}
+	if addr, err := checkIPv4Address(ip.DstIP); err != nil {
+		return fmt.Errorf("Invalid destination IPv4 address (%s)", err)
+	} else {
+		dst = addr
+	}
+	ip.SrcIP = src
+	ip.DstIP = dst
+	return nil
+}