header

package
v0.0.0-...-8cc07ee Latest Latest
Warning

This package is not in the latest version of its module.

 Go to latest Published: Nov 7, 2021 License: Apache-2.0 Imports: 6 Imported by: 16

Documentation

Overview

Package header provides the implementation of the encoding and decoding of network protocol headers.

Index

Constants

View Source 
const (
	// ARPProtocolNumber is the ARP network protocol number.
	ARPProtocolNumber tcpip.NetworkProtocolNumber = 0x0806

	// ARPSize is the size of an IPv4-over-Ethernet ARP packet.
	ARPSize = 2 + 2 + 1 + 1 + 2 + 2*6 + 2*4
)
View Source 
const (
	// EthernetMinimumSize is the minimum size of a valid ethernet frame.
	EthernetMinimumSize = 14

	// EthernetAddressSize is the size, in bytes, of an ethernet address.
	EthernetAddressSize = 6
)
View Source 
const (
	// ICMPv4MinimumSize is the minimum size of a valid ICMP packet.
	ICMPv4MinimumSize = 4

	// ICMPv4EchoMinimumSize is the minimum size of a valid ICMP echo packet.
	ICMPv4EchoMinimumSize = 6

	// ICMPv4DstUnreachableMinimumSize is the minimum size of a valid ICMP
	// destination unreachable packet.
	ICMPv4DstUnreachableMinimumSize = ICMPv4MinimumSize + 4

	// ICMPv4ProtocolNumber is the ICMP transport protocol number.
	ICMPv4ProtocolNumber tcpip.TransportProtocolNumber = 1
)
View Source 
const (
	ICMPv4PortUnreachable     = 3
	ICMPv4FragmentationNeeded = 4
)

Values for ICMP code as defined in RFC 792.

View Source 
const (
	// ICMPv6MinimumSize is the minimum size of a valid ICMP packet.
	ICMPv6MinimumSize = 4

	// ICMPv6ProtocolNumber is the ICMP transport protocol number.
	ICMPv6ProtocolNumber tcpip.TransportProtocolNumber = 58

	// ICMPv6NeighborSolicitMinimumSize is the minimum size of a
	// neighbor solicitation packet.
	ICMPv6NeighborSolicitMinimumSize = ICMPv6MinimumSize + 4 + 16

	// ICMPv6NeighborAdvertSize is size of a neighbor advertisement.
	ICMPv6NeighborAdvertSize = 32

	// ICMPv6EchoMinimumSize is the minimum size of a valid ICMP echo packet.
	ICMPv6EchoMinimumSize = 8

	// ICMPv6DstUnreachableMinimumSize is the minimum size of a valid ICMP
	// destination unreachable packet.
	ICMPv6DstUnreachableMinimumSize = ICMPv6MinimumSize + 4

	// ICMPv6PacketTooBigMinimumSize is the minimum size of a valid ICMP
	// packet-too-big packet.
	ICMPv6PacketTooBigMinimumSize = ICMPv6MinimumSize + 4
)
View Source 
const (
	// IPv4MinimumSize is the minimum size of a valid IPv4 packet.
	IPv4MinimumSize = 20

	// IPv4MaximumHeaderSize is the maximum size of an IPv4 header. Given
	// that there are only 4 bits to represents the header length in 32-bit
	// units, the header cannot exceed 15*4 = 60 bytes.
	IPv4MaximumHeaderSize = 60

	// IPv4AddressSize is the size, in bytes, of an IPv4 address.
	IPv4AddressSize = 4

	// IPv4ProtocolNumber is IPv4's network protocol number.
	IPv4ProtocolNumber tcpip.NetworkProtocolNumber = 0x0800

	// IPv4Version is the version of the ipv4 protocol.
	IPv4Version = 4

	// IPv4Broadcast is the broadcast address of the IPv4 procotol.
	IPv4Broadcast tcpip.Address = "\xff\xff\xff\xff"

	// IPv4Any is the non-routable IPv4 "any" meta address.
	IPv4Any tcpip.Address = "\x00\x00\x00\x00"
)
View Source 
const (
	IPv4FlagMoreFragments = 1 << iota
	IPv4FlagDontFragment
)

Flags that may be set in an IPv4 packet.

View Source 
const (
	// IPv6MinimumSize is the minimum size of a valid IPv6 packet.
	IPv6MinimumSize = 40

	// IPv6AddressSize is the size, in bytes, of an IPv6 address.
	IPv6AddressSize = 16

	// IPv6ProtocolNumber is IPv6's network protocol number.
	IPv6ProtocolNumber tcpip.NetworkProtocolNumber = 0x86dd

	// IPv6Version is the version of the ipv6 protocol.
	IPv6Version = 6

	// IPv6MinimumMTU is the minimum MTU required by IPv6, per RFC 2460,
	// section 5.
	IPv6MinimumMTU = 1280

	// IPv6Any is the non-routable IPv6 "any" meta address.
	IPv6Any tcpip.Address = "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
)
View Source 
const (
	// IPv6FragmentHeader header is the number used to specify that the next
	// header is a fragment header, per RFC 2460.
	IPv6FragmentHeader = 44

	// IPv6FragmentHeaderSize is the size of the fragment header.
	IPv6FragmentHeaderSize = 8
)
View Source 
const (
	TCPSrcPortOffset   = 0
	TCPDstPortOffset   = 2
	TCPSeqNumOffset    = 4
	TCPAckNumOffset    = 8
	TCPDataOffset      = 12
	TCPFlagsOffset     = 13
	TCPWinSizeOffset   = 14
	TCPChecksumOffset  = 16
	TCPUrgentPtrOffset = 18
)

These constants are the offsets of the respective fields in the TCP header.

View Source 
const (
	// MaxWndScale is maximum allowed window scaling, as described in
	// RFC 1323, section 2.3, page 11.
	MaxWndScale = 14

	// TCPMaxSACKBlocks is the maximum number of SACK blocks that can
	// be encoded in a TCP option field.
	TCPMaxSACKBlocks = 4
)
View Source 
const (
	TCPFlagFin = 1 << iota
	TCPFlagSyn
	TCPFlagRst
	TCPFlagPsh
	TCPFlagAck
	TCPFlagUrg
)

Flags that may be set in a TCP segment.

View Source 
const (
	TCPOptionEOL           = 0
	TCPOptionNOP           = 1
	TCPOptionMSS           = 2
	TCPOptionWS            = 3
	TCPOptionTS            = 8
	TCPOptionSACKPermitted = 4
	TCPOptionSACK          = 5
)

Options that may be present in a TCP segment.

View Source 
const (
	// TCPMinimumSize is the minimum size of a valid TCP packet.
	TCPMinimumSize = 20

	// TCPOptionsMaximumSize is the maximum size of TCP options.
	TCPOptionsMaximumSize = 40

	// TCPHeaderMaximumSize is the maximum header size of a TCP packet.
	TCPHeaderMaximumSize = TCPMinimumSize + TCPOptionsMaximumSize

	// TCPProtocolNumber is TCP's transport protocol number.
	TCPProtocolNumber tcpip.TransportProtocolNumber = 6
)
View Source 
const (
	// UDPMinimumSize is the minimum size of a valid UDP packet.
	UDPMinimumSize = 8

	// UDPProtocolNumber is UDP's transport protocol number.
	UDPProtocolNumber tcpip.TransportProtocolNumber = 17
)
View Source 
const (
	// GUEMinimumSize is the minimum size of a valid GUE packet.
	GUEMinimumSize = 4
)
View Source 
const (
	ICMPv6PortUnreachable = 4
)

Values for ICMP code as defined in RFC 4443.

View Source 
const (
	// MaxIPPacketSize is the maximum supported IP packet size, excluding
	// jumbograms. The maximum IPv4 packet size is 64k-1 (total size must fit
	// in 16 bits). For IPv6, the payload max size (excluding jumbograms) is
	// 64k-1 (also needs to fit in 16 bits). So we use 64k - 1 + 2 * m, where
	// m is the minimum IPv6 header size; we leave room for some potential
	// IP options.
	MaxIPPacketSize = 0xffff + 2*IPv6MinimumSize
)

Variables

This section is empty.

Functions

func AddTCPOptionPadding 

func AddTCPOptionPadding(options []byte, offset int) int

AddTCPOptionPadding adds the required number of TCPOptionNOP to quad align the option buffer. It adds padding bytes after the offset specified and returns the number of padding bytes added. The passed in options slice must have space for the padding bytes.

func Checksum 

func Checksum(buf []byte, initial uint16) uint16

Checksum calculates the checksum (as defined in RFC 1071) of the bytes in the given byte array.

The initial checksum must have been computed on an even number of bytes.

func ChecksumCombine 

func ChecksumCombine(a, b uint16) uint16

ChecksumCombine combines the two uint16 to form their checksum. This is done by adding them and the carry.

Note that checksum a must have been computed on an even number of bytes.

func ChecksumVV 

func ChecksumVV(vv buffer.VectorisedView, initial uint16) uint16

ChecksumVV calculates the checksum (as defined in RFC 1071) of the bytes in the given VectorizedView.

The initial checksum must have been computed on an even number of bytes.

func EncodeMSSOption 

func EncodeMSSOption(mss uint32, b []byte) int

EncodeMSSOption encodes the MSS TCP option with the provided MSS values in the supplied buffer. If the provided buffer is not large enough then it just returns without encoding anything. It returns the number of bytes written to the provided buffer.

func EncodeNOP 

func EncodeNOP(b []byte) int

EncodeNOP adds an explicit NOP to the option list.

func EncodeSACKBlocks 

func EncodeSACKBlocks(sackBlocks []SACKBlock, b []byte) int

EncodeSACKBlocks encodes the provided SACK blocks as a TCP SACK option block in the provided slice. It tries to fit in as many blocks as possible based on number of bytes available in the provided buffer. It returns the number of bytes written to the provided buffer.

func EncodeSACKPermittedOption 

func EncodeSACKPermittedOption(b []byte) int

EncodeSACKPermittedOption encodes a SACKPermitted option into the provided buffer. If the buffer is smaller than required it just returns without encoding anything. It returns the number of bytes written to the provided buffer.

func EncodeTSOption 

func EncodeTSOption(tsVal, tsEcr uint32, b []byte) int

EncodeTSOption encodes the provided tsVal and tsEcr values as a TCP timestamp option into the provided buffer. If the buffer is smaller than expected it just returns without encoding anything. It returns the number of bytes written to the provided buffer.

func EncodeWSOption 

func EncodeWSOption(ws int, b []byte) int

EncodeWSOption encodes the WS TCP option with the WS value in the provided buffer. If the provided buffer is not large enough then it just returns without encoding anything. It returns the number of bytes written to the provided buffer.

func IPVersion 

func IPVersion(b []byte) int

IPVersion returns the version of IP used in the given packet. It returns -1 if the packet is not large enough to contain the version field.

func IsV4MappedAddress 

func IsV4MappedAddress(addr tcpip.Address) bool

IsV4MappedAddress determines if the provided address is an IPv4 mapped address by checking if its prefix is 0:0:0:0:0:ffff::/96.

func IsV4MulticastAddress 

func IsV4MulticastAddress(addr tcpip.Address) bool

IsV4MulticastAddress determines if the provided address is an IPv4 multicast address (range 224.0.0.0 to 239.255.255.255). The four most significant bits will be 1110 = 0xe0.

func IsV6LinkLocalAddress 

func IsV6LinkLocalAddress(addr tcpip.Address) bool

IsV6LinkLocalAddress determines if the provided address is an IPv6 link-local address (fe80::/10).

func IsV6MulticastAddress 

func IsV6MulticastAddress(addr tcpip.Address) bool

IsV6MulticastAddress determines if the provided address is an IPv6 multicast address (anything starting with FF).

func LinkLocalAddr 

func LinkLocalAddr(linkAddr tcpip.LinkAddress) tcpip.Address

LinkLocalAddr computes the default IPv6 link-local address from a link-layer (MAC) address.

func PseudoHeaderChecksum 

func PseudoHeaderChecksum(protocol tcpip.TransportProtocolNumber, srcAddr tcpip.Address, dstAddr tcpip.Address, totalLen uint16) uint16

PseudoHeaderChecksum calculates the pseudo-header checksum for the given destination protocol and network address. Pseudo-headers are needed by transport layers when calculating their own checksum.

func SolicitedNodeAddr 

func SolicitedNodeAddr(addr tcpip.Address) tcpip.Address

SolicitedNodeAddr computes the solicited-node multicast address. This is used for NDP. Described in RFC 4291. The argument must be a full-length IPv6 address.

Types

type ARP 

type ARP []byte

ARP is an ARP packet stored in a byte array as described in RFC 826.

func (ARP) HardwareAddressSender 

func (a ARP) HardwareAddressSender() []byte

HardwareAddressSender is the link address of the sender. It is a view on to the ARP packet so it can be used to set the value.

func (ARP) HardwareAddressTarget 

func (a ARP) HardwareAddressTarget() []byte

HardwareAddressTarget is the link address of the target. It is a view on to the ARP packet so it can be used to set the value.

func (ARP) IsValid 

func (a ARP) IsValid() bool

IsValid reports whether this is an ARP packet for IPv4 over Ethernet.

func (ARP) Op 

func (a ARP) Op() ARPOp

Op is the ARP opcode.

func (ARP) ProtocolAddressSender 

func (a ARP) ProtocolAddressSender() []byte

ProtocolAddressSender is the protocol address of the sender. It is a view on to the ARP packet so it can be used to set the value.

func (ARP) ProtocolAddressTarget 

func (a ARP) ProtocolAddressTarget() []byte

ProtocolAddressTarget is the protocol address of the target. It is a view on to the ARP packet so it can be used to set the value.

func (ARP) SetIPv4OverEthernet 

func (a ARP) SetIPv4OverEthernet()

SetIPv4OverEthernet configures the ARP packet for IPv4-over-Ethernet.

func (ARP) SetOp 

func (a ARP) SetOp(op ARPOp)

SetOp sets the ARP opcode.

type ARPOp 

type ARPOp uint16

ARPOp is an ARP opcode. 

const (
	ARPRequest ARPOp = 1
	ARPReply   ARPOp = 2
)

Typical ARP opcodes defined in RFC 826.

type Ethernet 

type Ethernet []byte

Ethernet represents an ethernet frame header stored in a byte array.

func (Ethernet) DestinationAddress 

func (b Ethernet) DestinationAddress() tcpip.LinkAddress

DestinationAddress returns the "MAC destination" field of the ethernet frame header.

func (Ethernet) Encode 

func (b Ethernet) Encode(e *EthernetFields)

Encode encodes all the fields of the ethernet frame header.

func (Ethernet) SourceAddress 

func (b Ethernet) SourceAddress() tcpip.LinkAddress

SourceAddress returns the "MAC source" field of the ethernet frame header.

func (Ethernet) Type 

func (b Ethernet) Type() tcpip.NetworkProtocolNumber

Type returns the "ethertype" field of the ethernet frame header.

type EthernetFields 

type EthernetFields struct {
	// SrcAddr is the "MAC source" field of an ethernet frame header.
	SrcAddr tcpip.LinkAddress

	// DstAddr is the "MAC destination" field of an ethernet frame header.
	DstAddr tcpip.LinkAddress

	// Type is the "ethertype" field of an ethernet frame header.
	Type tcpip.NetworkProtocolNumber
}

EthernetFields contains the fields of an ethernet frame header. It is used to describe the fields of a frame that needs to be encoded.

type GUE 

type GUE []byte

GUE represents a Generic UDP Encapsulation header stored in a byte array, the fields are described in https://tools.ietf.org/html/draft-ietf-nvo3-gue-01.

func (GUE) Encode 

func (b GUE) Encode(i *GUEFields)

Encode encodes all the fields of the GUE header.

func (GUE) HeaderLength 

func (b GUE) HeaderLength() uint8

HeaderLength returns the total length of the GUE header.

func (GUE) Protocol 

func (b GUE) Protocol() uint8

Protocol returns the protocol field of the GUE header.

func (GUE) TypeAndControl 

func (b GUE) TypeAndControl() uint8

TypeAndControl returns the GUE packet type (top 3 bits of the first byte, which includes the control bit).

type GUEFields 

type GUEFields struct {
	// Type is the "type" field of the GUE header.
	Type uint8

	// Control is the "control" field of the GUE header.
	Control bool

	// HeaderLength is the "header length" field of the GUE header. It must
	// be at least 4 octets, and a multiple of 4 as well.
	HeaderLength uint8

	// Protocol is the "protocol" field of the GUE header. This is one of
	// the IPPROTO_* values.
	Protocol uint8
}

GUEFields contains the fields of a GUE packet. It is used to describe the fields of a packet that needs to be encoded.

type ICMPv4 

type ICMPv4 []byte

ICMPv4 represents an ICMPv4 header stored in a byte array.

func (ICMPv4) Checksum 

func (b ICMPv4) Checksum() uint16

Checksum is the ICMP checksum field.

func (ICMPv4) Code 

func (b ICMPv4) Code() byte

Code is the ICMP code field. Its meaning depends on the value of Type.

func (ICMPv4) DestinationPort 

func (ICMPv4) DestinationPort() uint16

DestinationPort implements Transport.DestinationPort.

func (ICMPv4) Payload 

func (b ICMPv4) Payload() []byte

Payload implements Transport.Payload.

func (ICMPv4) SetChecksum 

func (b ICMPv4) SetChecksum(checksum uint16)

SetChecksum sets the ICMP checksum field.

func (ICMPv4) SetCode 

func (b ICMPv4) SetCode(c byte)

SetCode sets the ICMP code field.

func (ICMPv4) SetDestinationPort 

func (ICMPv4) SetDestinationPort(uint16)

SetDestinationPort implements Transport.SetDestinationPort.

func (ICMPv4) SetSourcePort 

func (ICMPv4) SetSourcePort(uint16)

SetSourcePort implements Transport.SetSourcePort.

func (ICMPv4) SetType 

func (b ICMPv4) SetType(t ICMPv4Type)

SetType sets the ICMP type field.

func (ICMPv4) SourcePort 

func (ICMPv4) SourcePort() uint16

SourcePort implements Transport.SourcePort.

func (ICMPv4) Type 

func (b ICMPv4) Type() ICMPv4Type

Type is the ICMP type field.

type ICMPv4Type 

type ICMPv4Type byte

ICMPv4Type is the ICMP type field described in RFC 792. 

const (
	ICMPv4EchoReply      ICMPv4Type = 0
	ICMPv4DstUnreachable ICMPv4Type = 3
	ICMPv4SrcQuench      ICMPv4Type = 4
	ICMPv4Redirect       ICMPv4Type = 5
	ICMPv4Echo           ICMPv4Type = 8
	ICMPv4TimeExceeded   ICMPv4Type = 11
	ICMPv4ParamProblem   ICMPv4Type = 12
	ICMPv4Timestamp      ICMPv4Type = 13
	ICMPv4TimestampReply ICMPv4Type = 14
	ICMPv4InfoRequest    ICMPv4Type = 15
	ICMPv4InfoReply      ICMPv4Type = 16
)

Typical values of ICMPv4Type defined in RFC 792.

type ICMPv6 

type ICMPv6 []byte

ICMPv6 represents an ICMPv6 header stored in a byte array.

func (ICMPv6) Checksum 

func (b ICMPv6) Checksum() uint16

Checksum is the ICMP checksum field.

func (ICMPv6) Code 

func (b ICMPv6) Code() byte

Code is the ICMP code field. Its meaning depends on the value of Type.

func (ICMPv6) DestinationPort 

func (ICMPv6) DestinationPort() uint16

DestinationPort implements Transport.DestinationPort.

func (ICMPv6) Payload 

func (b ICMPv6) Payload() []byte

Payload implements Transport.Payload.

func (ICMPv6) SetChecksum 

func (b ICMPv6) SetChecksum(checksum uint16)

SetChecksum calculates and sets the ICMP checksum field.

func (ICMPv6) SetCode 

func (b ICMPv6) SetCode(c byte)

SetCode sets the ICMP code field.

func (ICMPv6) SetDestinationPort 

func (ICMPv6) SetDestinationPort(uint16)

SetDestinationPort implements Transport.SetDestinationPort.

func (ICMPv6) SetSourcePort 

func (ICMPv6) SetSourcePort(uint16)

SetSourcePort implements Transport.SetSourcePort.

func (ICMPv6) SetType 

func (b ICMPv6) SetType(t ICMPv6Type)

SetType sets the ICMP type field.

func (ICMPv6) SourcePort 

func (ICMPv6) SourcePort() uint16

SourcePort implements Transport.SourcePort.

func (ICMPv6) Type 

func (b ICMPv6) Type() ICMPv6Type

Type is the ICMP type field.

type ICMPv6Type 

type ICMPv6Type byte

ICMPv6Type is the ICMP type field described in RFC 4443 and friends. 

const (
	ICMPv6DstUnreachable ICMPv6Type = 1
	ICMPv6PacketTooBig   ICMPv6Type = 2
	ICMPv6TimeExceeded   ICMPv6Type = 3
	ICMPv6ParamProblem   ICMPv6Type = 4
	ICMPv6EchoRequest    ICMPv6Type = 128
	ICMPv6EchoReply      ICMPv6Type = 129

	ICMPv6RouterSolicit   ICMPv6Type = 133
	ICMPv6RouterAdvert    ICMPv6Type = 134
	ICMPv6NeighborSolicit ICMPv6Type = 135
	ICMPv6NeighborAdvert  ICMPv6Type = 136
	ICMPv6RedirectMsg     ICMPv6Type = 137
)

Typical values of ICMPv6Type defined in RFC 4443.

type IPv4 

type IPv4 []byte

IPv4 represents an ipv4 header stored in a byte array. Most of the methods of IPv4 access to the underlying slice without checking the boundaries and could panic because of 'index out of range'. Always call IsValid() to validate an instance of IPv4 before using other methods.

func (IPv4) CalculateChecksum 

func (b IPv4) CalculateChecksum() uint16

CalculateChecksum calculates the checksum of the ipv4 header.

func (IPv4) Checksum 

func (b IPv4) Checksum() uint16

Checksum returns the checksum field of the ipv4 header.

func (IPv4) DestinationAddress 

func (b IPv4) DestinationAddress() tcpip.Address

DestinationAddress returns the "destination address" field of the ipv4 header.

func (IPv4) Encode 

func (b IPv4) Encode(i *IPv4Fields)

Encode encodes all the fields of the ipv4 header.

func (IPv4) EncodePartial 

func (b IPv4) EncodePartial(partialChecksum, totalLength uint16)

EncodePartial updates the total length and checksum fields of ipv4 header, taking in the partial checksum, which is the checksum of the header without the total length and checksum fields. It is useful in cases when similar packets are produced.

func (IPv4) Flags 

func (b IPv4) Flags() uint8

Flags returns the "flags" field of the ipv4 header.

func (IPv4) FragmentOffset 

func (b IPv4) FragmentOffset() uint16

FragmentOffset returns the "fragment offset" field of the ipv4 header.

func (IPv4) HeaderLength 

func (b IPv4) HeaderLength() uint8

HeaderLength returns the value of the "header length" field of the ipv4 header.

func (IPv4) ID 

func (b IPv4) ID() uint16

ID returns the value of the identifier field of the ipv4 header.

func (IPv4) IsValid 

func (b IPv4) IsValid(pktSize int) bool

IsValid performs basic validation on the packet.

func (IPv4) Payload 

func (b IPv4) Payload() []byte

Payload implements Network.Payload.

func (IPv4) PayloadLength 

func (b IPv4) PayloadLength() uint16

PayloadLength returns the length of the payload portion of the ipv4 packet.

func (IPv4) Protocol 

func (b IPv4) Protocol() uint8

Protocol returns the value of the protocol field of the ipv4 header.

func (IPv4) SetChecksum 

func (b IPv4) SetChecksum(v uint16)

SetChecksum sets the checksum field of the ipv4 header.

func (IPv4) SetDestinationAddress 

func (b IPv4) SetDestinationAddress(addr tcpip.Address)

SetDestinationAddress sets the "destination address" field of the ipv4 header.

func (IPv4) SetFlagsFragmentOffset 

func (b IPv4) SetFlagsFragmentOffset(flags uint8, offset uint16)

SetFlagsFragmentOffset sets the "flags" and "fragment offset" fields of the ipv4 header.

func (IPv4) SetID 

func (b IPv4) SetID(v uint16)

SetID sets the identification field.

func (IPv4) SetSourceAddress 

func (b IPv4) SetSourceAddress(addr tcpip.Address)

SetSourceAddress sets the "source address" field of the ipv4 header.

func (IPv4) SetTOS 

func (b IPv4) SetTOS(v uint8, _ uint32)

SetTOS sets the "type of service" field of the ipv4 header.

func (IPv4) SetTotalLength 

func (b IPv4) SetTotalLength(totalLength uint16)

SetTotalLength sets the "total length" field of the ipv4 header.

func (IPv4) SourceAddress 

func (b IPv4) SourceAddress() tcpip.Address

SourceAddress returns the "source address" field of the ipv4 header.

func (IPv4) TOS 

func (b IPv4) TOS() (uint8, uint32)

TOS returns the "type of service" field of the ipv4 header.

func (IPv4) TTL 

func (b IPv4) TTL() uint8

TTL returns the "TTL" field of the ipv4 header.

func (IPv4) TotalLength 

func (b IPv4) TotalLength() uint16

TotalLength returns the "total length" field of the ipv4 header.

func (IPv4) TransportProtocol 

func (b IPv4) TransportProtocol() tcpip.TransportProtocolNumber

TransportProtocol implements Network.TransportProtocol.

type IPv4Fields 

type IPv4Fields struct {
	// IHL is the "internet header length" field of an IPv4 packet.
	IHL uint8

	// TOS is the "type of service" field of an IPv4 packet.
	TOS uint8

	// TotalLength is the "total length" field of an IPv4 packet.
	TotalLength uint16

	// ID is the "identification" field of an IPv4 packet.
	ID uint16

	// Flags is the "flags" field of an IPv4 packet.
	Flags uint8

	// FragmentOffset is the "fragment offset" field of an IPv4 packet.
	FragmentOffset uint16

	// TTL is the "time to live" field of an IPv4 packet.
	TTL uint8

	// Protocol is the "protocol" field of an IPv4 packet.
	Protocol uint8

	// Checksum is the "checksum" field of an IPv4 packet.
	Checksum uint16

	// SrcAddr is the "source ip address" of an IPv4 packet.
	SrcAddr tcpip.Address

	// DstAddr is the "destination ip address" of an IPv4 packet.
	DstAddr tcpip.Address
}

IPv4Fields contains the fields of an IPv4 packet. It is used to describe the fields of a packet that needs to be encoded.

type IPv6 

type IPv6 []byte

IPv6 represents an ipv6 header stored in a byte array. Most of the methods of IPv6 access to the underlying slice without checking the boundaries and could panic because of 'index out of range'. Always call IsValid() to validate an instance of IPv6 before using other methods.

func (IPv6) Checksum 

func (IPv6) Checksum() uint16

Checksum implements Network.Checksum. Given that IPv6 doesn't have a checksum, it just returns 0.

func (IPv6) DestinationAddress 

func (b IPv6) DestinationAddress() tcpip.Address

DestinationAddress returns the "destination address" field of the ipv6 header.

func (IPv6) Encode 

func (b IPv6) Encode(i *IPv6Fields)

Encode encodes all the fields of the ipv6 header.

func (IPv6) HopLimit 

func (b IPv6) HopLimit() uint8

HopLimit returns the value of the "hop limit" field of the ipv6 header.

func (IPv6) IsValid 

func (b IPv6) IsValid(pktSize int) bool

IsValid performs basic validation on the packet.

func (IPv6) NextHeader 

func (b IPv6) NextHeader() uint8

NextHeader returns the value of the "next header" field of the ipv6 header.

func (IPv6) Payload 

func (b IPv6) Payload() []byte

Payload implements Network.Payload.

func (IPv6) PayloadLength 

func (b IPv6) PayloadLength() uint16

PayloadLength returns the value of the "payload length" field of the ipv6 header.

func (IPv6) SetChecksum 

func (IPv6) SetChecksum(uint16)

SetChecksum implements Network.SetChecksum. Given that IPv6 doesn't have a checksum, it is empty.

func (IPv6) SetDestinationAddress 

func (b IPv6) SetDestinationAddress(addr tcpip.Address)

SetDestinationAddress sets the "destination address" field of the ipv6 header.

func (IPv6) SetNextHeader 

func (b IPv6) SetNextHeader(v uint8)

SetNextHeader sets the value of the "next header" field of the ipv6 header.

func (IPv6) SetPayloadLength 

func (b IPv6) SetPayloadLength(payloadLength uint16)

SetPayloadLength sets the "payload length" field of the ipv6 header.

func (IPv6) SetSourceAddress 

func (b IPv6) SetSourceAddress(addr tcpip.Address)

SetSourceAddress sets the "source address" field of the ipv6 header.

func (IPv6) SetTOS 

func (b IPv6) SetTOS(t uint8, l uint32)

SetTOS sets the "traffic class" and "flow label" fields of the ipv6 header.

func (IPv6) SourceAddress 

func (b IPv6) SourceAddress() tcpip.Address

SourceAddress returns the "source address" field of the ipv6 header.

func (IPv6) TOS 

func (b IPv6) TOS() (uint8, uint32)

TOS returns the "traffic class" and "flow label" fields of the ipv6 header.

func (IPv6) TransportProtocol 

func (b IPv6) TransportProtocol() tcpip.TransportProtocolNumber

TransportProtocol implements Network.TransportProtocol.

type IPv6Fields 

type IPv6Fields struct {
	// TrafficClass is the "traffic class" field of an IPv6 packet.
	TrafficClass uint8

	// FlowLabel is the "flow label" field of an IPv6 packet.
	FlowLabel uint32

	// PayloadLength is the "payload length" field of an IPv6 packet.
	PayloadLength uint16

	// NextHeader is the "next header" field of an IPv6 packet.
	NextHeader uint8

	// HopLimit is the "hop limit" field of an IPv6 packet.
	HopLimit uint8

	// SrcAddr is the "source ip address" of an IPv6 packet.
	SrcAddr tcpip.Address

	// DstAddr is the "destination ip address" of an IPv6 packet.
	DstAddr tcpip.Address
}

IPv6Fields contains the fields of an IPv6 packet. It is used to describe the fields of a packet that needs to be encoded.

type IPv6Fragment 

type IPv6Fragment []byte

IPv6Fragment represents an ipv6 fragment header stored in a byte array. Most of the methods of IPv6Fragment access to the underlying slice without checking the boundaries and could panic because of 'index out of range'. Always call IsValid() to validate an instance of IPv6Fragment before using other methods.

func (IPv6Fragment) Checksum 

func (b IPv6Fragment) Checksum() uint16

Checksum is not supported by IPv6Fragment.

func (IPv6Fragment) DestinationAddress 

func (b IPv6Fragment) DestinationAddress() tcpip.Address

DestinationAddress is not supported by IPv6Fragment.

func (IPv6Fragment) Encode 

func (b IPv6Fragment) Encode(i *IPv6FragmentFields)

Encode encodes all the fields of the ipv6 fragment.

func (IPv6Fragment) FragmentOffset 

func (b IPv6Fragment) FragmentOffset() uint16

FragmentOffset returns the "fragment offset" field of the ipv6 fragment.

func (IPv6Fragment) ID 

func (b IPv6Fragment) ID() uint32

ID returns the value of the identifier field of the ipv6 fragment.

func (IPv6Fragment) IsValid 

func (b IPv6Fragment) IsValid() bool

IsValid performs basic validation on the fragment header.

func (IPv6Fragment) More 

func (b IPv6Fragment) More() bool

More returns the "more" field of the ipv6 fragment.

func (IPv6Fragment) NextHeader 

func (b IPv6Fragment) NextHeader() uint8

NextHeader returns the value of the "next header" field of the ipv6 fragment.

func (IPv6Fragment) Payload 

func (b IPv6Fragment) Payload() []byte

Payload implements Network.Payload.

func (IPv6Fragment) SetChecksum 

func (b IPv6Fragment) SetChecksum(uint16)

SetChecksum is not supported by IPv6Fragment.

func (IPv6Fragment) SetDestinationAddress 

func (b IPv6Fragment) SetDestinationAddress(tcpip.Address)

SetDestinationAddress is not supported by IPv6Fragment.

func (IPv6Fragment) SetSourceAddress 

func (b IPv6Fragment) SetSourceAddress(tcpip.Address)

SetSourceAddress is not supported by IPv6Fragment.

func (IPv6Fragment) SetTOS 

func (b IPv6Fragment) SetTOS(t uint8, l uint32)

SetTOS is not supported by IPv6Fragment.

func (IPv6Fragment) SourceAddress 

func (b IPv6Fragment) SourceAddress() tcpip.Address

SourceAddress is not supported by IPv6Fragment.

func (IPv6Fragment) TOS 

func (b IPv6Fragment) TOS() (uint8, uint32)

TOS is not supported by IPv6Fragment.

func (IPv6Fragment) TransportProtocol 

func (b IPv6Fragment) TransportProtocol() tcpip.TransportProtocolNumber

TransportProtocol implements Network.TransportProtocol.

type IPv6FragmentFields 

type IPv6FragmentFields struct {
	// NextHeader is the "next header" field of an IPv6 fragment.
	NextHeader uint8

	// FragmentOffset is the "fragment offset" field of an IPv6 fragment.
	FragmentOffset uint16

	// M is the "more" field of an IPv6 fragment.
	M bool

	// Identification is the "identification" field of an IPv6 fragment.
	Identification uint32
}

IPv6FragmentFields contains the fields of an IPv6 fragment. It is used to describe the fields of a packet that needs to be encoded.

type Network 

type Network interface {
	// SourceAddress returns the value of the "source address" field.
	SourceAddress() tcpip.Address

	// DestinationAddress returns the value of the "destination address"
	// field.
	DestinationAddress() tcpip.Address

	// Checksum returns the value of the "checksum" field.
	Checksum() uint16

	// SetSourceAddress sets the value of the "source address" field.
	SetSourceAddress(tcpip.Address)

	// SetDestinationAddress sets the value of the "destination address"
	// field.
	SetDestinationAddress(tcpip.Address)

	// SetChecksum sets the value of the "checksum" field.
	SetChecksum(uint16)

	// TransportProtocol returns the number of the transport protocol
	// stored in the payload.
	TransportProtocol() tcpip.TransportProtocolNumber

	// Payload returns a byte slice containing the payload of the network
	// packet.
	Payload() []byte

	// TOS returns the values of the "type of service" and "flow label" fields.
	TOS() (uint8, uint32)

	// SetTOS sets the values of the "type of service" and "flow label" fields.
	SetTOS(t uint8, l uint32)
}

Network offers generic methods to query and/or update the fields of the header of a network protocol buffer.

type SACKBlock 

type SACKBlock struct {
	// Start indicates the lowest sequence number in the block.
	Start seqnum.Value

	// End indicates the sequence number immediately following the last
	// sequence number of this block.
	End seqnum.Value
}

SACKBlock represents a single contiguous SACK block.

+stateify savable

func (SACKBlock) Contains 

func (r SACKBlock) Contains(b SACKBlock) bool

Contains returns true if b is completely contained in r.

func (SACKBlock) Less 

func (r SACKBlock) Less(b btree.Item) bool

Less returns true if r.Start < b.Start.

type TCP 

type TCP []byte

TCP represents a TCP header stored in a byte array.

func (TCP) AckNumber 

func (b TCP) AckNumber() uint32

AckNumber returns the "ack number" field of the tcp header.

func (TCP) CalculateChecksum 

func (b TCP) CalculateChecksum(partialChecksum uint16) uint16

CalculateChecksum calculates the checksum of the tcp segment. partialChecksum is the checksum of the network-layer pseudo-header and the checksum of the segment data.

func (TCP) Checksum 

func (b TCP) Checksum() uint16

Checksum returns the "checksum" field of the tcp header.

func (TCP) DataOffset 

func (b TCP) DataOffset() uint8

DataOffset returns the "data offset" field of the tcp header.

func (TCP) DestinationPort 

func (b TCP) DestinationPort() uint16

DestinationPort returns the "destination port" field of the tcp header.

func (TCP) Encode 

func (b TCP) Encode(t *TCPFields)

Encode encodes all the fields of the tcp header.

func (TCP) EncodePartial 

func (b TCP) EncodePartial(partialChecksum, length uint16, seqnum, acknum uint32, flags byte, rcvwnd uint16)

EncodePartial updates a subset of the fields of the tcp header. It is useful in cases when similar segments are produced.

func (TCP) Flags 

func (b TCP) Flags() uint8

Flags returns the flags field of the tcp header.

func (TCP) Options 

func (b TCP) Options() []byte

Options returns a slice that holds the unparsed TCP options in the segment.

func (TCP) ParsedOptions 

func (b TCP) ParsedOptions() TCPOptions

ParsedOptions returns a TCPOptions structure which parses and caches the TCP option values in the TCP segment. NOTE: Invoking this function repeatedly is expensive as it reparses the options on each invocation.

func (TCP) Payload 

func (b TCP) Payload() []byte

Payload returns the data in the tcp packet.

func (TCP) SequenceNumber 

func (b TCP) SequenceNumber() uint32

SequenceNumber returns the "sequence number" field of the tcp header.

func (TCP) SetChecksum 

func (b TCP) SetChecksum(checksum uint16)

SetChecksum sets the checksum field of the tcp header.

func (TCP) SetDestinationPort 

func (b TCP) SetDestinationPort(port uint16)

SetDestinationPort sets the "destination port" field of the tcp header.

func (TCP) SetSourcePort 

func (b TCP) SetSourcePort(port uint16)

SetSourcePort sets the "source port" field of the tcp header.

func (TCP) SourcePort 

func (b TCP) SourcePort() uint16

SourcePort returns the "source port" field of the tcp header.

func (TCP) WindowSize 

func (b TCP) WindowSize() uint16

WindowSize returns the "window size" field of the tcp header.

type TCPFields 

type TCPFields struct {
	// SrcPort is the "source port" field of a TCP packet.
	SrcPort uint16

	// DstPort is the "destination port" field of a TCP packet.
	DstPort uint16

	// SeqNum is the "sequence number" field of a TCP packet.
	SeqNum uint32

	// AckNum is the "acknowledgement number" field of a TCP packet.
	AckNum uint32

	// DataOffset is the "data offset" field of a TCP packet.
	DataOffset uint8

	// Flags is the "flags" field of a TCP packet.
	Flags uint8

	// WindowSize is the "window size" field of a TCP packet.
	WindowSize uint16

	// Checksum is the "checksum" field of a TCP packet.
	Checksum uint16

	// UrgentPointer is the "urgent pointer" field of a TCP packet.
	UrgentPointer uint16
}

TCPFields contains the fields of a TCP packet. It is used to describe the fields of a packet that needs to be encoded.

type TCPOptions 

type TCPOptions struct {
	// TS is true if the TimeStamp option is enabled.
	TS bool

	// TSVal is the value in the TSVal field of the segment.
	TSVal uint32

	// TSEcr is the value in the TSEcr field of the segment.
	TSEcr uint32

	// SACKBlocks are the SACK blocks specified in the segment.
	SACKBlocks []SACKBlock
}

TCPOptions are used to parse and cache the TCP segment options for a non syn/syn-ack segment.

+stateify savable

func ParseTCPOptions 

func ParseTCPOptions(b []byte) TCPOptions

ParseTCPOptions extracts and stores all known options in the provided byte slice in a TCPOptions structure.

type TCPSynOptions 

type TCPSynOptions struct {
	// MSS is the maximum segment size provided by the peer in the SYN.
	MSS uint16

	// WS is the window scale option provided by the peer in the SYN.
	//
	// Set to -1 if no window scale option was provided.
	WS int

	// TS is true if the timestamp option was provided in the syn/syn-ack.
	TS bool

	// TSVal is the value of the TSVal field in the timestamp option.
	TSVal uint32

	// TSEcr is the value of the TSEcr field in the timestamp option.
	TSEcr uint32

	// SACKPermitted is true if the SACK option was provided in the SYN/SYN-ACK.
	SACKPermitted bool
}

TCPSynOptions is used to return the parsed TCP Options in a syn segment.

func ParseSynOptions 

func ParseSynOptions(opts []byte, isAck bool) TCPSynOptions

ParseSynOptions parses the options received in a SYN segment and returns the relevant ones. opts should point to the option part of the TCP Header.

type Transport 

type Transport interface {
	// SourcePort returns the value of the "source port" field.
	SourcePort() uint16

	// Destination returns the value of the "destination port" field.
	DestinationPort() uint16

	// Checksum returns the value of the "checksum" field.
	Checksum() uint16

	// SetSourcePort sets the value of the "source port" field.
	SetSourcePort(uint16)

	// SetDestinationPort sets the value of the "destination port" field.
	SetDestinationPort(uint16)

	// SetChecksum sets the value of the "checksum" field.
	SetChecksum(uint16)

	// Payload returns the data carried in the transport buffer.
	Payload() []byte
}

Transport offers generic methods to query and/or update the fields of the header of a transport protocol buffer.

type UDP 

type UDP []byte

UDP represents a UDP header stored in a byte array.

func (UDP) CalculateChecksum 

func (b UDP) CalculateChecksum(partialChecksum uint16) uint16

CalculateChecksum calculates the checksum of the udp packet, given the checksum of the network-layer pseudo-header and the checksum of the payload.

func (UDP) Checksum 

func (b UDP) Checksum() uint16

Checksum returns the "checksum" field of the udp header.

func (UDP) DestinationPort 

func (b UDP) DestinationPort() uint16

DestinationPort returns the "destination port" field of the udp header.

func (UDP) Encode 

func (b UDP) Encode(u *UDPFields)

Encode encodes all the fields of the udp header.

func (UDP) Length 

func (b UDP) Length() uint16

Length returns the "length" field of the udp header.

func (UDP) Payload 

func (b UDP) Payload() []byte

Payload returns the data contained in the UDP datagram.

func (UDP) SetChecksum 

func (b UDP) SetChecksum(checksum uint16)

SetChecksum sets the "checksum" field of the udp header.

func (UDP) SetDestinationPort 

func (b UDP) SetDestinationPort(port uint16)

SetDestinationPort sets the "destination port" field of the udp header.

func (UDP) SetSourcePort 

func (b UDP) SetSourcePort(port uint16)

SetSourcePort sets the "source port" field of the udp header.

func (UDP) SourcePort 

func (b UDP) SourcePort() uint16

SourcePort returns the "source port" field of the udp header.

type UDPFields 

type UDPFields struct {
	// SrcPort is the "source port" field of a UDP packet.
	SrcPort uint16

	// DstPort is the "destination port" field of a UDP packet.
	DstPort uint16

	// Length is the "length" field of a UDP packet.
	Length uint16

	// Checksum is the "checksum" field of a UDP packet.
	Checksum uint16
}

UDPFields contains the fields of a UDP packet. It is used to describe the fields of a packet that needs to be encoded.

Source Files

View all Source files

Jump to

Keyboard shortcuts

? : This menu
/ : Search site
f or F : Jump to
y or Y : Canonical URL
go.dev uses cookies from Google to deliver and enhance the quality of its services and to analyze traffic. Learn more.