tcpconntrack

Documentation

Overview

Package tcpconntrack implements a TCP connection tracking object. It allows users with access to a segment stream to figure out when a connection is established, reset, and closed (and in the last case, who closed first).

Index

• type Result
• type TCB
  • func (t *TCB) InboundSendSequenceNumber() seqnum.Value
  • func (t *TCB) Init(initialSyn header.TCP)
  • func (t *TCB) IsAlive() bool
  • func (t *TCB) OutboundSendSequenceNumber() seqnum.Value
  • func (t *TCB) UpdateStateInbound(tcp header.TCP) Result
  • func (t *TCB) UpdateStateOutbound(tcp header.TCP) Result

Types

type Result

type Result int

Result is returned when the state of a TCB is updated in response to an inbound or outbound segment.

const (
	// ResultDrop indicates that the segment should be dropped.
	ResultDrop Result = iota

	// ResultConnecting indicates that the connection remains in a
	// connecting state.
	ResultConnecting

	// ResultAlive indicates that the connection remains alive (connected).
	ResultAlive

	// ResultReset indicates that the connection was reset.
	ResultReset

	// ResultClosedByPeer indicates that the connection was gracefully
	// closed, and the inbound stream was closed first.
	ResultClosedByPeer

	// ResultClosedBySelf indicates that the connection was gracefully
	// closed, and the outbound stream was closed first.
	ResultClosedBySelf
)

type TCB

type TCB struct {
	// contains filtered or unexported fields
}

TCB is a TCP Control Block. It holds state necessary to keep track of a TCP connection and inform the caller when the connection has been closed.

func (*TCB) InboundSendSequenceNumber

func (t *TCB) InboundSendSequenceNumber() seqnum.Value

InboundSendSequenceNumber returns the snd.NXT for the inbound stream.

func (*TCB) Init

func (t *TCB) Init(initialSyn header.TCP)

Init initializes the state of the TCB according to the initial SYN.

func (*TCB) IsAlive

func (t *TCB) IsAlive() bool

IsAlive returns true as long as the connection is established(Alive) or connecting state.

func (*TCB) OutboundSendSequenceNumber

func (t *TCB) OutboundSendSequenceNumber() seqnum.Value

OutboundSendSequenceNumber returns the snd.NXT for the outbound stream.

func (*TCB) UpdateStateInbound

func (t *TCB) UpdateStateInbound(tcp header.TCP) Result

UpdateStateInbound updates the state of the TCB based on the supplied inbound segment.

func (*TCB) UpdateStateOutbound

func (t *TCB) UpdateStateOutbound(tcp header.TCP) Result

UpdateStateOutbound updates the state of the TCB based on the supplied outbound segment.