socks5

type AddrSpec struct {
	FQDN string
	IP   net.IP
	Port int
}

type AddressRewriter interface {
	Rewrite(ctx context.Context, request *Request) (context.Context, *AddrSpec)
}

type AuthContext struct {
	// Provided auth method
	Method uint8
	// Payload provided during negotiation.
	// Keys depend on the used auth method.
	// For UserPassAuth contains Username
	Payload map[string]string
}

type Authenticator interface {
	Authenticate(reader io.Reader, writer io.Writer) (*AuthContext, error)
	GetCode() uint8
}

type Config struct {
	// can be provided to implement custom authentication
	// By default, "auth-less" mode is enabled.
	// For password-based auth use UserPassAuthenticator.
	AuthMethods []Authenticator

	// If provided, username/password authentication is enabled,
	// by appending a UserPassAuthenticator to AuthMethods. If not provided,
	// and AUthMethods is nil, then "auth-less" mode is enabled.
	Credentials CredentialStore

	// can be provided to do custom name resolution.
	// Defaults to NoOpResolver if not provided.
	Resolver NameResolver

	// Rules is provided to enable custom logic around permitting
	// various commands. If not provided, PermitAll is used.
	Rules RuleSet

	// can be used to transparently rewrite addresses.
	// This is invoked before the RuleSet is invoked.
	// Defaults to NoRewrite.
	Rewriter AddressRewriter

	// server queries handler
	// Defaults to SinglePortUDPHandler
	Handler Handler
}

type ContextGo interface {
	Ctx() context.Context
	GoNoError(f func())
	Go(f func() error)
	Cancel()
}

type CredentialStore interface {
	Valid(user, password string) bool
}

type DNSResolver struct{}

type ErrorLogger interface {
	Printf(format string, v ...interface{})
}

type Handler interface {
	// Called, when Serve is called on socks server. Server will be really started only after returning from this func.
	// Returned error will abort socks server starting.
	OnStartServe(ctxServer ContextGo, tcp net.Listener) error

	// Must return valid non-nil ErrorLogger
	// May be called only after OnStartServe is called
	ErrLog() ErrorLogger

	// Called on every "connect" query from client. May block if needed, but must obey ctx cancellation.
	// Returned error will only abort current client's connection and will not stop server.
	OnConnect(ctx context.Context, conn net.Conn, req *Request) error

	// Called on every "associate" query from client. May block if needed, but must obey ctx cancellation
	// Returned error will only abort current client's connection and will not stop server.
	OnAssociate(ctx context.Context, conn net.Conn, req *Request) error
}

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

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

type NameResolver interface {
	Resolve(ctx context.Context, name string) (context.Context, net.IP, error)
}

type NoAuthAuthenticator struct{}

type NoOpResolver struct{}

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

type PermitCommand struct {
	EnableConnect   bool
	EnableBind      bool
	EnableAssociate bool
}

type RemoteUDPConn interface {
	Send(ctx context.Context, data []byte, remoteAddr *AddrSpec) error
	Close() error
}

type RemoteUDPConnFactory interface {
	MakeRemoteUDPConn(ctxClient ContextGo, ctxServer ContextGo, sendBack UDPSendBack, onBroken func()) (RemoteUDPConn, error)
	MaxUDPPacketSize() uint
}

type Request struct {
	// Protocol version
	Version uint8
	// Requested command
	Command uint8
	// AuthContext provided during negotiation
	AuthContext *AuthContext
	// AddrSpec of the the network that sent the request
	RemoteAddr *AddrSpec
	// AddrSpec of the desired destination
	DestAddr *AddrSpec
	// contains filtered or unexported fields
}

type RuleSet interface {
	Allow(ctx context.Context, req *Request) (context.Context, bool)
}

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

type SinglePortUDPHandler struct {

	// used for udp associate, defaults to automatically chosen free UDP port
	UDPListenPort int
	// contains filtered or unexported fields
}

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

type StaticCredentials map[string]string

type UDPSendBack func(remoteAddr *AddrSpec, data []byte) error

type UDPSendBackTo func(remoteAddr *AddrSpec, data []byte, client *net.UDPAddr) error

type UserPassAuthenticator struct {
	Credentials CredentialStore
}