package tcpconntrack

import "gvisor.dev/gvisor/pkg/tcpip/transport/tcpconntrack"

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) Init(initialSyn header.TCP, dataLen int) Result
• func (t *TCB) IsAlive() bool
• func (t *TCB) IsEmpty() bool
• func (t *TCB) OriginalSendSequenceNumber() seqnum.Value
• func (t *TCB) ReplySendSequenceNumber() seqnum.Value
• func (t *TCB) State() Result
• func (t *TCB) UpdateStateOriginal(tcp header.TCP, dataLen int) Result
• func (t *TCB) UpdateStateReply(tcp header.TCP, dataLen int) Result

Types ¶

type Result ¶

type Result int

Result is returned when the state of a TCB is updated in response to a 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

	// ResultClosedByResponder indicates that the connection was gracefully
	// closed, and the reply stream was closed first.
	ResultClosedByResponder

	// ResultClosedByOriginator indicates that the connection was gracefully
	// closed, and the original stream was closed first.
	ResultClosedByOriginator
)

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.

+stateify savable

func (*TCB) Init ¶

func (t *TCB) Init(initialSyn header.TCP, dataLen int) Result

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) IsEmpty ¶

func (t *TCB) IsEmpty() bool

IsEmpty returns true if tcb is not initialized.

func (*TCB) OriginalSendSequenceNumber ¶

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

OriginalSendSequenceNumber returns the snd.NXT for the original stream.

func (*TCB) ReplySendSequenceNumber ¶

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

ReplySendSequenceNumber returns the snd.NXT for the reply stream.

func (*TCB) State ¶

func (t *TCB) State() Result

State returns the current state of the TCB.

func (*TCB) UpdateStateOriginal ¶

func (t *TCB) UpdateStateOriginal(tcp header.TCP, dataLen int) Result

UpdateStateOriginal updates the state of the TCB based on the supplied original segment.

func (*TCB) UpdateStateReply ¶

func (t *TCB) UpdateStateReply(tcp header.TCP, dataLen int) Result

UpdateStateReply updates the state of the TCB based on the supplied reply segment.

Source Files ¶

tcp_conntrack.go