layers

package
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 Go to latest Published: Feb 1, 2024 License: GPL-3.0 Imports: 8 Imported by: 0

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Index

Constants

View Source 
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
)
View Source 
const (
	// IPv6HopByHopOptionJumbogram code as defined in RFC 2675
	IPv6HopByHopOptionJumbogram = 0xC2
)

Variables

View Source 
var (
	// We use two different endpoint types for IPv4 vs IPv6 addresses, so that
	// ordering with endpointA.LessThan(endpointB) sanely groups all IPv4
	// addresses and all IPv6 addresses, such that IPv6 > IPv4 for all addresses.
	EndpointIPv4 = gopacket.RegisterEndpointType(1, gopacket.EndpointTypeMetadata{Name: "IPv4", Formatter: func(b []byte) string {
		return net.IP(b).String()
	}})
	EndpointIPv6 = gopacket.RegisterEndpointType(2, gopacket.EndpointTypeMetadata{Name: "IPv6", Formatter: func(b []byte) string {
		return net.IP(b).String()
	}})

	EndpointTCPPort = gopacket.RegisterEndpointType(4, gopacket.EndpointTypeMetadata{Name: "TCP", Formatter: func(b []byte) string {
		return strconv.Itoa(int(binary.BigEndian.Uint16(b)))
	}})
	EndpointUDPPort = gopacket.RegisterEndpointType(5, gopacket.EndpointTypeMetadata{Name: "UDP", Formatter: func(b []byte) string {
		return strconv.Itoa(int(binary.BigEndian.Uint16(b)))
	}})
)
View Source 
var (
	LayerTypeIPv4            = gopacket.RegisterLayerType(20, gopacket.LayerTypeMetadata{Name: "IPv4", Decoder: gopacket.DecodeFunc(decodeIPv4)})
	LayerTypeIPv6            = gopacket.RegisterLayerType(21, gopacket.LayerTypeMetadata{Name: "IPv6", Decoder: gopacket.DecodeFunc(decodeIPv6)})
	LayerTypeTCP             = gopacket.RegisterLayerType(44, gopacket.LayerTypeMetadata{Name: "TCP", Decoder: gopacket.DecodeFunc(decodeTCP)})
	LayerTypeUDP             = gopacket.RegisterLayerType(45, gopacket.LayerTypeMetadata{Name: "UDP", Decoder: gopacket.DecodeFunc(decodeUDP)})
	LayerTypeIPv6HopByHop    = gopacket.RegisterLayerType(46, gopacket.LayerTypeMetadata{Name: "IPv6HopByHop", Decoder: gopacket.DecodeFunc(decodeIPv6HopByHop)})
	LayerTypeIPv6Routing     = gopacket.RegisterLayerType(47, gopacket.LayerTypeMetadata{Name: "IPv6Routing", Decoder: gopacket.DecodeFunc(decodeIPv6Routing)})
	LayerTypeIPv6Fragment    = gopacket.RegisterLayerType(48, gopacket.LayerTypeMetadata{Name: "IPv6Fragment", Decoder: gopacket.DecodeFunc(decodeIPv6Fragment)})
	LayerTypeIPv6Destination = gopacket.RegisterLayerType(49, gopacket.LayerTypeMetadata{Name: "IPv6Destination", Decoder: gopacket.DecodeFunc(decodeIPv6Destination)})
)
View Source 
var (
	// LayerClassIPNetwork contains TCP/IP network layer types.
	LayerClassIPNetwork = gopacket.NewLayerClass([]gopacket.LayerType{
		LayerTypeIPv4,
		LayerTypeIPv6,
	})
	// LayerClassIPTransport contains TCP/IP transport layer types.
	LayerClassIPTransport = gopacket.NewLayerClass([]gopacket.LayerType{
		LayerTypeTCP,
		LayerTypeUDP,
	})
	// LayerClassIPv6Extension contains IPv6 extension headers.
	LayerClassIPv6Extension = gopacket.NewLayerClass([]gopacket.LayerType{
		LayerTypeIPv6HopByHop,
		LayerTypeIPv6Routing,
		LayerTypeIPv6Fragment,
		LayerTypeIPv6Destination,
	})
)
View Source 
var IPProtocolMetadata [256]EnumMetadata
View Source 
var ProtocolFamilyMetadata [256]EnumMetadata

Functions

func NewIPEndpoint 

func NewIPEndpoint(a net.IP) gopacket.Endpoint

NewIPEndpoint creates a new IP (v4 or v6) endpoint from a net.IP address. It returns gopacket.InvalidEndpoint if the IP address is invalid.

func NewTCPPortEndpoint 

func NewTCPPortEndpoint(p TCPPort) gopacket.Endpoint

NewTCPPortEndpoint returns an endpoint based on a TCP port.

func NewUDPPortEndpoint 

func NewUDPPortEndpoint(p UDPPort) gopacket.Endpoint

NewUDPPortEndpoint returns an endpoint based on a UDP port.

Types

type BaseLayer 

type BaseLayer struct {
	// Contents is the set of bytes that make up this layer.  IE: for an
	// Ethernet packet, this would be the set of bytes making up the
	// Ethernet frame.
	Contents []byte
	// Payload is the set of bytes contained by (but not part of) this
	// Layer.  Again, to take Ethernet as an example, this would be the
	// set of bytes encapsulated by the Ethernet protocol.
	Payload []byte
}

BaseLayer is a convenience struct which implements the LayerData and LayerPayload functions of the Layer interface.

func (*BaseLayer) LayerContents 

func (b *BaseLayer) LayerContents() []byte

LayerContents returns the bytes of the packet layer.

func (*BaseLayer) LayerPayload 

func (b *BaseLayer) LayerPayload() []byte

LayerPayload returns the bytes contained within the packet layer.

type EnumMetadata 

type EnumMetadata struct {
	// DecodeWith is the decoder to use to decode this protocol's data.
	DecodeWith gopacket.Decoder
	// Name is the name of the enumeration value.
	Name string
	// LayerType is the layer type implied by the given enum.
	LayerType gopacket.LayerType
}

EnumMetadata keeps track of a set of metadata for each enumeration value for protocol enumerations.

type IPProtocol 

type IPProtocol uint8

IPProtocol is an enumeration of IP protocol values, and acts as a decoder for any type it supports. 

const (
	IPProtocolIPv6HopByHop    IPProtocol = 0
	IPProtocolIPv4            IPProtocol = 4
	IPProtocolTCP             IPProtocol = 6
	IPProtocolUDP             IPProtocol = 17
	IPProtocolIPv6            IPProtocol = 41
	IPProtocolIPv6Routing     IPProtocol = 43
	IPProtocolIPv6Fragment    IPProtocol = 44
	IPProtocolNoNextHeader    IPProtocol = 59
	IPProtocolIPv6Destination IPProtocol = 60
)

func (IPProtocol) Decode 

func (a IPProtocol) Decode(data []byte, p gopacket.PacketBuilder) error

Decoder calls IPProtocolMetadata.DecodeWith's decoder.

func (IPProtocol) LayerType 

func (a IPProtocol) LayerType() gopacket.LayerType

LayerType returns IPProtocolMetadata.LayerType.

func (IPProtocol) String 

func (a IPProtocol) String() string

String returns IPProtocolMetadata.Name.

type IPv4 

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
}

IPv4 is the header of an IP packet.

func (*IPv4) AddressTo4 

func (ip *IPv4) AddressTo4() error

func (*IPv4) CanDecode 

func (i *IPv4) CanDecode() gopacket.LayerClass

func (*IPv4) DecodeFromBytes 

func (ip *IPv4) DecodeFromBytes(data []byte, df gopacket.DecodeFeedback) error

DecodeFromBytes decodes the given bytes into this layer.

func (*IPv4) LayerType 

func (i *IPv4) LayerType() gopacket.LayerType

LayerType returns LayerTypeIPv4

func (*IPv4) NetworkFlow 

func (i *IPv4) NetworkFlow() gopacket.Flow

func (*IPv4) NextLayerType 

func (i *IPv4) NextLayerType() gopacket.LayerType

func (*IPv4) SerializeTo 

func (ip *IPv4) SerializeTo(b gopacket.SerializeBuffer, opts gopacket.SerializeOptions) error

SerializeTo writes the serialized form of this layer into the SerializationBuffer, implementing gopacket.SerializableLayer.

type IPv4Flag 

type IPv4Flag uint8
const (
	IPv4EvilBit       IPv4Flag = 1 << 2 // http://tools.ietf.org/html/rfc3514 ;)
	IPv4DontFragment  IPv4Flag = 1 << 1
	IPv4MoreFragments IPv4Flag = 1 << 0
)

func (IPv4Flag) String 

func (f IPv4Flag) String() string

type IPv4Option 

type IPv4Option struct {
	OptionType   uint8
	OptionLength uint8
	OptionData   []byte
}

func (IPv4Option) String 

func (i IPv4Option) String() string

type IPv6 

type IPv6 struct {
	// http://www.networksorcery.com/enp/protocol/ipv6.htm
	BaseLayer
	Version      uint8
	TrafficClass uint8
	FlowLabel    uint32
	Length       uint16
	NextHeader   IPProtocol
	HopLimit     uint8
	SrcIP        net.IP
	DstIP        net.IP
	HopByHop     *IPv6HopByHop
	// contains filtered or unexported fields
}

IPv6 is the layer for the IPv6 header.

func (*IPv6) AddressTo16 

func (ipv6 *IPv6) AddressTo16() error

AddressTo16 ensures IPv6.SrcIP and IPv6.DstIP are actually IPv6 addresses (i.e. 16 byte addresses)

func (*IPv6) CanDecode 

func (ipv6 *IPv6) CanDecode() gopacket.LayerClass

CanDecode implementation according to gopacket.DecodingLayer

func (*IPv6) DecodeFromBytes 

func (ipv6 *IPv6) DecodeFromBytes(data []byte, df gopacket.DecodeFeedback) error

DecodeFromBytes implementation according to gopacket.DecodingLayer

func (*IPv6) LayerType 

func (ipv6 *IPv6) LayerType() gopacket.LayerType

LayerType returns LayerTypeIPv6

func (*IPv6) NetworkFlow 

func (ipv6 *IPv6) NetworkFlow() gopacket.Flow

NetworkFlow returns this new Flow (EndpointIPv6, SrcIP, DstIP)

func (*IPv6) NextLayerType 

func (ipv6 *IPv6) NextLayerType() gopacket.LayerType

NextLayerType implementation according to gopacket.DecodingLayer

func (*IPv6) SerializeTo 

func (ipv6 *IPv6) SerializeTo(b gopacket.SerializeBuffer, opts gopacket.SerializeOptions) error

SerializeTo writes the serialized form of this layer into the SerializationBuffer, implementing gopacket.SerializableLayer. See the docs for gopacket.SerializableLayer for more info.

type IPv6Destination 

type IPv6Destination struct {
	Options []*IPv6DestinationOption
	// contains filtered or unexported fields
}

IPv6Destination is the IPv6 destination options header.

func (*IPv6Destination) DecodeFromBytes 

func (i *IPv6Destination) DecodeFromBytes(data []byte, df gopacket.DecodeFeedback) error

DecodeFromBytes implementation according to gopacket.DecodingLayer

func (*IPv6Destination) LayerType 

func (i *IPv6Destination) LayerType() gopacket.LayerType

LayerType returns LayerTypeIPv6Destination.

func (*IPv6Destination) SerializeTo 

func (i *IPv6Destination) SerializeTo(b gopacket.SerializeBuffer, opts gopacket.SerializeOptions) error

SerializeTo writes the serialized form of this layer into the SerializationBuffer, implementing gopacket.SerializableLayer. See the docs for gopacket.SerializableLayer for more info.

type IPv6DestinationOption 

type IPv6DestinationOption ipv6HeaderTLVOption

IPv6DestinationOption is a TLV option present in an IPv6 destination options extension.

type IPv6ExtensionSkipper 

type IPv6ExtensionSkipper struct {
	NextHeader IPProtocol
	BaseLayer
}

IPv6ExtensionSkipper is a DecodingLayer which decodes and ignores v6 extensions. You can use it with a DecodingLayerParser to handle IPv6 stacks which may or may not have extensions.

func (*IPv6ExtensionSkipper) CanDecode 

func (i *IPv6ExtensionSkipper) CanDecode() gopacket.LayerClass

CanDecode implementation according to gopacket.DecodingLayer

func (*IPv6ExtensionSkipper) DecodeFromBytes 

func (i *IPv6ExtensionSkipper) DecodeFromBytes(data []byte, df gopacket.DecodeFeedback) error

DecodeFromBytes implementation according to gopacket.DecodingLayer

func (*IPv6ExtensionSkipper) NextLayerType 

func (i *IPv6ExtensionSkipper) NextLayerType() gopacket.LayerType

NextLayerType implementation according to gopacket.DecodingLayer

type IPv6Fragment 

type IPv6Fragment struct {
	BaseLayer
	NextHeader IPProtocol
	// Reserved1 is bits [8-16), from least to most significant, 0-indexed
	Reserved1      uint8
	FragmentOffset uint16
	// Reserved2 is bits [29-31), from least to most significant, 0-indexed
	Reserved2      uint8
	MoreFragments  bool
	Identification uint32
}

IPv6Fragment is the IPv6 fragment header, used for packet fragmentation/defragmentation.

func (*IPv6Fragment) LayerType 

func (i *IPv6Fragment) LayerType() gopacket.LayerType

LayerType returns LayerTypeIPv6Fragment.

type IPv6HopByHop 

type IPv6HopByHop struct {
	Options []*IPv6HopByHopOption
	// contains filtered or unexported fields
}

IPv6HopByHop is the IPv6 hop-by-hop extension.

func (*IPv6HopByHop) DecodeFromBytes 

func (i *IPv6HopByHop) DecodeFromBytes(data []byte, df gopacket.DecodeFeedback) error

DecodeFromBytes implementation according to gopacket.DecodingLayer

func (*IPv6HopByHop) LayerType 

func (i *IPv6HopByHop) LayerType() gopacket.LayerType

LayerType returns LayerTypeIPv6HopByHop.

func (*IPv6HopByHop) SerializeTo 

func (i *IPv6HopByHop) SerializeTo(b gopacket.SerializeBuffer, opts gopacket.SerializeOptions) error

SerializeTo implementation according to gopacket.SerializableLayer

type IPv6HopByHopOption 

type IPv6HopByHopOption ipv6HeaderTLVOption

IPv6HopByHopOption is a TLV option present in an IPv6 hop-by-hop extension.

func (*IPv6HopByHopOption) SetJumboLength 

func (o *IPv6HopByHopOption) SetJumboLength(len uint32)

SetJumboLength adds the IPv6HopByHopOptionJumbogram with the given length

type IPv6Routing 

type IPv6Routing struct {
	RoutingType  uint8
	SegmentsLeft uint8
	// This segment is supposed to be zero according to RFC2460, the second set of
	// 4 bytes in the extension.
	Reserved []byte
	// SourceRoutingIPs is the set of IPv6 addresses requested for source routing,
	// set only if RoutingType == 0.
	SourceRoutingIPs []net.IP
	// contains filtered or unexported fields
}

IPv6Routing is the IPv6 routing extension.

func (*IPv6Routing) LayerType 

func (i *IPv6Routing) LayerType() gopacket.LayerType

LayerType returns LayerTypeIPv6Routing.

type ProtocolFamily 

type ProtocolFamily uint8

ProtocolFamily is the set of values defined as PF_* in sys/socket.h 

const (
	ProtocolFamilyIPv4 ProtocolFamily = 2
	// BSDs use different values for INET6... glory be.  These values taken from
	// tcpdump 4.3.0.
	ProtocolFamilyIPv6BSD     ProtocolFamily = 24
	ProtocolFamilyIPv6FreeBSD ProtocolFamily = 28
	ProtocolFamilyIPv6Darwin  ProtocolFamily = 30
	ProtocolFamilyIPv6Linux   ProtocolFamily = 10
)

func (ProtocolFamily) Decode 

func (a ProtocolFamily) Decode(data []byte, p gopacket.PacketBuilder) error

Decoder calls ProtocolFamilyMetadata.DecodeWith's decoder.

func (ProtocolFamily) LayerType 

func (a ProtocolFamily) LayerType() gopacket.LayerType

LayerType returns ProtocolFamilyMetadata.LayerType.

func (ProtocolFamily) String 

func (a ProtocolFamily) String() string

String returns ProtocolFamilyMetadata.Name.

type TCP 

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

	Options []TCPOption
	Padding []byte
	// contains filtered or unexported fields
}

TCP is the layer for TCP headers.

func (*TCP) CanDecode 

func (t *TCP) CanDecode() gopacket.LayerClass

func (*TCP) ComputeChecksum 

func (t *TCP) ComputeChecksum() (uint16, error)

func (*TCP) DecodeFromBytes 

func (tcp *TCP) DecodeFromBytes(data []byte, df gopacket.DecodeFeedback) error

func (*TCP) LayerType 

func (t *TCP) LayerType() gopacket.LayerType

LayerType returns gopacket.LayerTypeTCP

func (*TCP) NextLayerType 

func (t *TCP) NextLayerType() gopacket.LayerType

func (*TCP) SerializeTo 

func (t *TCP) SerializeTo(b gopacket.SerializeBuffer, opts gopacket.SerializeOptions) error

SerializeTo writes the serialized form of this layer into the SerializationBuffer, implementing gopacket.SerializableLayer. See the docs for gopacket.SerializableLayer for more info.

func (*TCP) SetInternalPortsForTesting 

func (t *TCP) SetInternalPortsForTesting()

For testing only

func (*TCP) SetNetworkLayerForChecksum 

func (i *TCP) SetNetworkLayerForChecksum(l gopacket.NetworkLayer) error

SetNetworkLayerForChecksum tells this layer which network layer is wrapping it. This is needed for computing the checksum when serializing, since TCP/IP transport layer checksums depends on fields in the IPv4 or IPv6 layer that contains it. The passed in layer must be an *IPv4 or *IPv6.

func (*TCP) TransportFlow 

func (t *TCP) TransportFlow() gopacket.Flow

type TCPOption 

type TCPOption struct {
	OptionType   TCPOptionKind
	OptionLength uint8
	OptionData   []byte
}

func (TCPOption) String 

func (t TCPOption) String() string

type TCPOptionKind 

type TCPOptionKind uint8

TCPOptionKind represents a TCP option code.

func (TCPOptionKind) String 

func (k TCPOptionKind) String() string

type TCPPort 

type TCPPort uint16

TCPPort is a port in a TCP layer.

func (TCPPort) LayerType 

func (a TCPPort) LayerType() gopacket.LayerType

LayerType returns a LayerType that would be able to decode the application payload. It uses some well-known ports such as 53 for DNS.

Returns gopacket.LayerTypePayload for unknown/unsupported port numbers.

func (TCPPort) String 

func (a TCPPort) String() string

String returns the port as "number(name)" if there's a well-known port name, or just "number" if there isn't. Well-known names are stored in TCPPortNames.

type UDP 

type UDP struct {
	BaseLayer
	SrcPort, DstPort UDPPort
	Length           uint16
	Checksum         uint16
	// contains filtered or unexported fields
}

UDP is the layer for UDP headers.

func (*UDP) CanDecode 

func (u *UDP) CanDecode() gopacket.LayerClass

func (*UDP) DecodeFromBytes 

func (udp *UDP) DecodeFromBytes(data []byte, df gopacket.DecodeFeedback) error

func (*UDP) LayerType 

func (u *UDP) LayerType() gopacket.LayerType

LayerType returns gopacket.LayerTypeUDP

func (*UDP) NextLayerType 

func (u *UDP) NextLayerType() gopacket.LayerType

NextLayerType use the destination port to select the right next decoder. It tries first to decode via the destination port, then the source port.

func (*UDP) SerializeTo 

func (u *UDP) SerializeTo(b gopacket.SerializeBuffer, opts gopacket.SerializeOptions) error

SerializeTo writes the serialized form of this layer into the SerializationBuffer, implementing gopacket.SerializableLayer. See the docs for gopacket.SerializableLayer for more info.

func (*UDP) SetInternalPortsForTesting 

func (u *UDP) SetInternalPortsForTesting()

For testing only

func (*UDP) SetNetworkLayerForChecksum 

func (i *UDP) SetNetworkLayerForChecksum(l gopacket.NetworkLayer) error

SetNetworkLayerForChecksum tells this layer which network layer is wrapping it. This is needed for computing the checksum when serializing, since TCP/IP transport layer checksums depends on fields in the IPv4 or IPv6 layer that contains it. The passed in layer must be an *IPv4 or *IPv6.

func (*UDP) TransportFlow 

func (u *UDP) TransportFlow() gopacket.Flow

type UDPPort 

type UDPPort uint16

UDPPort is a port in a UDP layer.

func (UDPPort) LayerType 

func (a UDPPort) LayerType() gopacket.LayerType

LayerType returns a LayerType that would be able to decode the application payload. It uses some well-known ports such as 53 for DNS.

Returns gopacket.LayerTypePayload for unknown/unsupported port numbers.

func (UDPPort) String 

func (a UDPPort) String() string

String returns the port as "number(name)" if there's a well-known port name, or just "number" if there isn't. Well-known names are stored in UDPPortNames.

Source Files

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