model

type Dialer interface {
	DialContext(context.Context, string, string) (net.Conn, error)
}

type Direction int

type DummyTracer struct{}

type HandshakeTracer interface {
	// TimeNow allows to inject time for deterministic tests.
	TimeNow() time.Time

	// OnStateChange is called for each transition in the state machine.
	OnStateChange(state NegotiationState)

	// OnIncomingPacket is called when a packet is received.
	OnIncomingPacket(packet *Packet, stage NegotiationState)

	// OnOutgoingPacket is called when a packet is about to be sent.
	OnOutgoingPacket(packet *Packet, stage NegotiationState, retries int)

	// OnDroppedPacket is called whenever a packet is dropped (in/out)
	OnDroppedPacket(direction Direction, stage NegotiationState, packet *Packet)
}

type Logger interface {
	// Debug emits a debug message.
	Debug(msg string)

	// Debugf formats and emits a debug message.
	Debugf(format string, v ...any)

	// Info emits an informational message.
	Info(msg string)

	// Infof formats and emits an informational message.
	Infof(format string, v ...any)

	// Warn emits a warning message.
	Warn(msg string)

	// Warnf formats and emits a warning message.
	Warnf(format string, v ...any)
}

type NegotiationState int

type Notification struct {
	// Flags contains flags explaining what happened.
	Flags int64
}

type Opcode byte

type Packet struct {
	// Opcode is the packet message type (a P_* constant; high 5-bits of
	// the first packet byte).
	Opcode Opcode

	// The key_id refers to an already negotiated TLS session.
	// This is the shortened version of the key-id (low 3-bits of the first
	// packet byte).
	KeyID byte

	// PeerID is the peer ID.
	PeerID PeerID

	// LocalSessionID is the local session ID.
	LocalSessionID SessionID

	// Acks contains the remote packets we're ACKing.
	ACKs []PacketID

	// RemoteSessionID is the remote session ID.
	RemoteSessionID SessionID

	// ID is the packet-id for replay protection. According to the spec: "4 or 8 bytes,
	// includes sequence number and optional time_t timestamp".
	//
	// This library does not use the timestamp.
	// TODO(ainghazal): use optional.Value (only control packets have packet id)
	ID PacketID

	// Payload is the packet's payload.
	Payload []byte
}

type PacketID uint32

type PeerID [3]byte

type SessionID [8]byte

type TestLogger struct {
	Lines []string
}

type TunnelInfo struct {
	// GW is the Route Gateway.
	GW string

	// IP is the assigned IP.
	IP string

	// MTU is the configured MTU pushed by the remote.
	MTU int

	// NetMask is the netmask configured on the TUN interface, pushed by the ifconfig command.
	NetMask string

	// PeerID is the peer-id assigned to us by the remote.
	PeerID int
}