upstream

Documentation

Index

• type Event
• type EventObserver
• type Opt
• type Upstream
  • func NewUpstream(addr string, opt Opt) (Upstream, error)

Types

type Event

type Event int

const (
	EventConnOpen Event = iota
	EventConnClose
)

type EventObserver

type EventObserver interface {
	OnEvent(typ Event)
}

type Opt

type Opt struct {
	// DialAddr specifies the address the upstream will
	// actually dial to.
	DialAddr string

	// Socks5 specifies the socks5 proxy server that the upstream
	// will connect though.
	// Not implemented for udp upstreams and doh upstreams with http/3.
	Socks5 string

	// SoMark sets the socket SO_MARK option in unix system.
	SoMark int

	// BindToDevice sets the socket SO_BINDTODEVICE option in unix system.
	BindToDevice string

	// IdleTimeout specifies the idle timeout for long-connections.
	// Available for TCP, DoT, DoH.
	// If negative, TCP, DoT will not reuse connections.
	// Default: TCP, DoT: 10s , DoH: 30s.
	IdleTimeout time.Duration

	// EnablePipeline enables query pipelining support as RFC 7766 6.2.1.1 suggested.
	// Available for TCP, DoT upstream with IdleTimeout >= 0.
	EnablePipeline bool

	// EnableHTTP3 enables HTTP/3 protocol for DoH upstream.
	EnableHTTP3 bool

	// MaxConns limits the total number of connections, including connections
	// in the dialing states.
	// Implemented for TCP/DoT pipeline enabled upstreams and DoH upstreams.
	// Default is 2.
	MaxConns int

	// Bootstrap specifies a plain dns server for the go runtime to solve the
	// domain of the upstream server. It SHOULD be an IP address. Custom port
	// is supported.
	// Note: Use a domain address may cause dead resolve loop and additional
	// latency to dial upstream server.
	// HTTP3 is not supported.
	Bootstrap string

	// TLSConfig specifies the tls.Config that the TLS client will use.
	// Available for DoT, DoH upstreams.
	TLSConfig *tls.Config

	// Logger specifies the logger that the upstream will use.
	Logger *zap.Logger

	// EventObserver can observe connection events.
	// Note: Not Implemented for HTTP/3 upstreams.
	EventObserver EventObserver
}

type Upstream

type Upstream interface {
	// ExchangeContext exchanges query message m to the upstream, and returns
	// response. It MUST NOT keep or modify m.
	ExchangeContext(ctx context.Context, m *dns.Msg) (*dns.Msg, error)

	io.Closer
}

Upstream represents a DNS upstream.

func NewUpstream

func NewUpstream(addr string, opt Opt) (Upstream, error)