socket_oob

README

Socket OOB Control Message Utils for Go

Experimental

Planned features

• append, read, modify, remove
  • generic socket OOB control messages
  • ECN flags
  • GSO size
  • IPv6 destination options

Supported Systems

Currently only Linux is supported.

References

• https://man7.org/linux/man-pages/man7/ip.7.html
• https://man7.org/linux/man-pages/man7/ipv6.7.html
• https://man7.org/linux/man-pages/man7/udp.7.html
• https://man7.org/linux/man-pages/man7/tcp.7.html

Documentation

Index

• Constants
• Variables
• func DstOptsLen(datalen int) int
• func EnableGRO(conn *net.UDPConn) error
• func IsGROEnabled(conn *net.UDPConn) bool
• func IsGROSupported(conn *net.UDPConn) bool
• func IsGSOSupported(conn *net.UDPConn) bool
• func WriteGSO(conn *net.UDPConn, b []byte, size uint16, addr netip.AddrPort, oob []byte) (n int, oobn int, err error)
• type Cmsg
• type DstOptsHdr
• type ECN
  • func (e ECN) ToHeaderBits() byte
• type Iterator
• type Segments
  • func ReadGRO(conn *net.UDPConn, b []byte, oob []byte) (Segments, []byte, int, netip.AddrPort, error)
  • func (s *Segments) First() []byte
  • func (s *Segments) Iterator() Iterator[[]byte]
  • func (s *Segments) Len() int
  • func (s *Segments) Split(left func(segment []byte) bool) (Segments, Segments)

Constants

const (
	DestOptTypePad0 byte = 0
	DestOptTypePadN      = 1
)

const DstOptsHdrLen = 2

const MaxGSOBufSize = math.MaxUint16 - 8

Variables

var CmsgHdrSpace int

Functions

func DstOptsLen

func DstOptsLen(datalen int) int

func EnableGRO

func EnableGRO(conn *net.UDPConn) error

func IsGROEnabled

func IsGROEnabled(conn *net.UDPConn) bool

IsGROEnabled tests if GSO is enabled on this socket. Sending with GRO might still fail later on, if the interface doesn't support it.

func IsGROSupported

func IsGROSupported(conn *net.UDPConn) bool

IsGROSupported tests if the kernel supports GRO. Sending with GRO might still fail later on, if the interface doesn't support it.

func IsGSOSupported

func IsGSOSupported(conn *net.UDPConn) bool

IsGSOSupported tests if the kernel supports GSO. Sending with GSO might still fail later on, if the interface doesn't support it.

func WriteGSO

func WriteGSO(conn *net.UDPConn, b []byte, size uint16, addr netip.AddrPort, oob []byte) (n int, oobn int, err error)

WriteGSO uses generic segmentation offload

Types

type Cmsg

type Cmsg struct {
	Hdr  *unix.Cmsghdr
	Data []byte
}

type DstOptsHdr

type DstOptsHdr struct {
	NextHeader            uint8
	HeaderExtensionLength uint8
}

type ECN

type ECN uint8

const (
	ECNUnsupported ECN = iota
	ECNNon             // 00
	ECT1               // 01
	ECT0               // 10
	ECNCE              // 11
)

func (ECN) ToHeaderBits

func (e ECN) ToHeaderBits() byte

type Iterator

type Iterator[T any] interface {
	HasNext() bool
	Next() T
}

type Segments

type Segments struct {
	Buf            []byte
	MaxSegmentSize int
}

Segments represents a series of network packets in one byte array. all segments have MaxSegmentSize except the last one might be smaller.

func ReadGRO

func ReadGRO(conn *net.UDPConn, b []byte, oob []byte) (Segments, []byte, int, netip.AddrPort, error)

ReadGRO uses generic receive offload

func (*Segments) First

func (s *Segments) First() []byte

func (*Segments) Iterator

func (s *Segments) Iterator() Iterator[[]byte]

func (*Segments) Len

func (s *Segments) Len() int

func (*Segments) Split

func (s *Segments) Split(left func(segment []byte) bool) (Segments, Segments)