upstream

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

type ConsequentResolver = types.ConsequentResolver

type DialHandler func(ctx context.Context, network string, addr string) (conn net.Conn, err error)

type DialerInitializer func() (handler DialHandler, err error)

type ExchangeAllResult struct {
	// Resp is the response DNS request resolved into.
	Resp *dns.Msg

	// Upstream is the upstream that successfully resolved the request.
	Upstream Upstream
}

type HTTPVersion string

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

type Network = types.Network

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

type Options struct {
	// Logger is used for logging during parsing and upstream exchange.  If nil,
	// [slog.Default] is used.
	Logger *slog.Logger

	// VerifyServerCertificate is used to set the VerifyPeerCertificate property
	// of the *tls.Config for DNS-over-HTTPS, DNS-over-QUIC, and DNS-over-TLS.
	VerifyServerCertificate func(rawCerts [][]byte, verifiedChains [][]*x509.Certificate) error

	// VerifyConnection is used to set the VerifyConnection property
	// of the *tls.Config for DNS-over-HTTPS, DNS-over-QUIC, and DNS-over-TLS.
	VerifyConnection func(state tls.ConnectionState) error

	// VerifyDNSCryptCertificate is the callback the DNSCrypt server certificate
	// will be passed to.  It's called in dnsCrypt.exchangeDNSCrypt.
	// Upstream.Exchange method returns any error caused by it.
	VerifyDNSCryptCertificate func(cert *dnscrypt.Cert) error

	// QUICTracer is an optional callback that allows tracing every QUIC
	// connection and logging every packet that goes through.
	QUICTracer QUICTraceFunc

	// RootCAs is the CertPool that must be used by all upstreams.  Redefining
	// RootCAs makes sense on iOS to overcome the 15MB memory limit of the
	// NEPacketTunnelProvider.
	RootCAs *x509.CertPool

	// CipherSuites is a custom list of TLSv1.2 ciphers.
	CipherSuites []uint16

	// Bootstrap is used to resolve upstreams' hostnames.  If nil, the
	// [net.DefaultResolver] will be used.
	Bootstrap Resolver

	// HTTPVersions is a list of HTTP versions that should be supported by the
	// DNS-over-HTTPS client.  If not set, HTTP/1.1 and HTTP/2 will be used.
	HTTPVersions []HTTPVersion

	// Timeout is the default upstream timeout.  It's also used as a timeout for
	// bootstrap DNS requests.  Zero value disables the timeout.
	Timeout time.Duration

	// InsecureSkipVerify disables verifying the server's certificate.
	InsecureSkipVerify bool

	// PreferIPv6 tells the bootstrapper to prefer IPv6 addresses for an
	// upstream.
	PreferIPv6 bool
}

type ParallelResolver = types.ParallelResolver

type QUICTraceFunc func(
	ctx context.Context,
	role logging.Perspective,
	connID quic.ConnectionID,
) (tracer *logging.ConnectionTracer)

type Resolver = types.Resolver

type StaticResolver = types.StaticResolver

type Upstream interface {
	// Exchange sends req to this upstream and returns the response that has
	// been received or an error if something went wrong.  The implementations
	// must not modify req as well as the caller must not modify it until the
	// method returns.  It shouldn't be called after closing.
	Exchange(req *dns.Msg) (resp *dns.Msg, err error)

	// Address returns the human-readable address of the upstream DNS resolver.
	// It may differ from what was passed to [AddressToUpstream].
	Address() (addr string)

	// Closer used to close the upstreams properly.
	io.Closer
}

type UpstreamOptions interface {
	// Getter methods for Options fields
	GetLogger() *slog.Logger
	GetVerifyServerCertificate() func(rawCerts [][]byte, verifiedChains [][]*x509.Certificate) error
	GetVerifyConnection() func(state tls.ConnectionState) error
	GetVerifyDNSCryptCertificate() func(cert *dnscrypt.Cert) error
	GetQUICTracer() QUICTraceFunc
	GetRootCAs() *x509.CertPool
	GetCipherSuites() []uint16
	GetBootstrap() Resolver
	GetHTTPVersions() []HTTPVersion
	GetTimeout() time.Duration
	GetInsecureSkipVerify() bool
	GetPreferIPv6() bool

	// DialTCP creates a TCP connection to the specified address using the
	// configuration from this UpstreamOptions.
	DialTCP(ctx context.Context, addr string) (net.Conn, error)

	// DialUDP creates a UDP connection to the specified address using the
	// configuration from this UpstreamOptions.
	DialUDP(ctx context.Context, addr string) (*net.UDPConn, error)

	// LookupIP resolves a hostname to IP addresses using the bootstrap resolver.
	// This method has the same interface as net.LookupIP.
	LookupIP(host string) ([]net.IP, error)

	// Setter methods for mutable fields
	SetLogger(logger *slog.Logger)
	SetBootstrap(bootstrap Resolver)

	Clone() (clone UpstreamOptions)
}

type UpstreamResolver struct {
	// Upstream is used for lookups.  It must not be nil.
	Upstream
}