feat(x): make config support PacketListeners and make dependencies explicit and decoupled

x/configurl/config.go

@@ -15,108 +15,84 @@
 package configurl
 
 import (
+	"context"
 	"errors"
 	"fmt"
 	"net/url"
-	"strconv"
 	"strings"
-
-	"github.com/Jigsaw-Code/outline-sdk/transport"
-	"github.com/Jigsaw-Code/outline-sdk/transport/tlsfrag"
 )
 
-// ConfigToDialer enables the creation of stream and packet dialers based on a config. The config is
-// extensible by registering wrappers for config subtypes.
-type ConfigToDialer struct {
-	// Base StreamDialer to create direct stream connections. If you need direct stream connections, this must not be nil.
-	BaseStreamDialer transport.StreamDialer
-	// Base PacketDialer to create direct packet connections. If you need direct packet connections, this must not be nil.
-	BasePacketDialer transport.PacketDialer
-	sdBuilders       map[string]NewStreamDialerFunc
-	pdBuilders       map[string]NewPacketDialerFunc
+// Config is a pre-parsed generic config created from pipe-separated URLs.
+type Config struct {
+	URL        url.URL
+	BaseConfig *Config
 }
 
-// NewStreamDialerFunc wraps a Dialer based on the wrapConfig. The innerSD and innerPD functions can provide a base Stream and Packet Dialers if needed.
-type NewStreamDialerFunc func(innerSD func() (transport.StreamDialer, error), innerPD func() (transport.PacketDialer, error), wrapConfig *url.URL) (transport.StreamDialer, error)
-
-// NewPacketDialerFunc wraps a Dialer based on the wrapConfig. The innerSD and innerPD functions can provide a base Stream and Packet Dialers if needed.
-type NewPacketDialerFunc func(innerSD func() (transport.StreamDialer, error), innerPD func() (transport.PacketDialer, error), wrapConfig *url.URL) (transport.PacketDialer, error)
-
-// NewDefaultConfigToDialer creates a [ConfigToDialer] with a set of default wrappers already registered.
-func NewDefaultConfigToDialer() *ConfigToDialer {
-	p := new(ConfigToDialer)
-	p.BaseStreamDialer = &transport.TCPDialer{}
-	p.BasePacketDialer = &transport.UDPDialer{}
-
-	// Please keep the list in alphabetical order.
-	p.RegisterStreamDialerType("do53", wrapStreamDialerWithDO53)
-
-	p.RegisterStreamDialerType("doh", wrapStreamDialerWithDOH)
-
-	p.RegisterStreamDialerType("override", wrapStreamDialerWithOverride)
-	p.RegisterPacketDialerType("override", wrapPacketDialerWithOverride)
-
-	p.RegisterStreamDialerType("socks5", wrapStreamDialerWithSOCKS5)
-	p.RegisterPacketDialerType("socks5", wrapPacketDialerWithSOCKS5)
-
-	p.RegisterStreamDialerType("split", wrapStreamDialerWithSplit)
+// BuildFunc is a function that creates an instance of ObjectType given a [Config].
+type BuildFunc[ObjectType any] func(ctx context.Context, config *Config) (ObjectType, error)
 
-	p.RegisterStreamDialerType("ss", wrapStreamDialerWithShadowsocks)
-	p.RegisterPacketDialerType("ss", wrapPacketDialerWithShadowsocks)
-
-	p.RegisterStreamDialerType("tls", wrapStreamDialerWithTLS)
+// TypeRegistry registers config types.
+type TypeRegistry[ObjectType any] interface {
+	RegisterType(subtype string, newInstance BuildFunc[ObjectType])
+}
 
-	p.RegisterStreamDialerType("tlsfrag", func(innerSD func() (transport.StreamDialer, error), innerPD func() (transport.PacketDialer, error), wrapConfig *url.URL) (transport.StreamDialer, error) {
-		sd, err := innerSD()
-		if err != nil {
-			return nil, err
-		}
-		lenStr := wrapConfig.Opaque
-		fixedLen, err := strconv.Atoi(lenStr)
-		if err != nil {
-			return nil, fmt.Errorf("invalid tlsfrag option: %v. It should be in tlsfrag:<number> format", lenStr)
-		}
-		return tlsfrag.NewFixedLenStreamDialer(sd, fixedLen)
-	})
+// ExtensibleProvider creates instances of ObjectType in a way that can be extended via its [TypeRegistry] interface.
+type ExtensibleProvider[ObjectType comparable] struct {
+	// Instance to return when config is nil.
+	BaseInstance ObjectType
+	builders     map[string]BuildFunc[ObjectType]
+}
 
-	p.RegisterStreamDialerType("ws", wrapStreamDialerWithWebSocket)
-	p.RegisterPacketDialerType("ws", wrapPacketDialerWithWebSocket)
+var (
+	_ BuildFunc[any]    = (*ExtensibleProvider[any])(nil).NewInstance
+	_ TypeRegistry[any] = (*ExtensibleProvider[any])(nil)
+)
 
-	return p
+// NewExtensibleProvider creates an [ExtensibleProvider] with the given base instance.
+func NewExtensibleProvider[ObjectType comparable](baseInstance ObjectType) ExtensibleProvider[ObjectType] {
+	return ExtensibleProvider[ObjectType]{
+		BaseInstance: baseInstance,
+		builders:     make(map[string]BuildFunc[ObjectType]),
+	}
 }
 
-// RegisterStreamDialerType will register a wrapper for stream dialers under the given subtype.
-func (p *ConfigToDialer) RegisterStreamDialerType(subtype string, newDialer NewStreamDialerFunc) error {
-	if p.sdBuilders == nil {
-		p.sdBuilders = make(map[string]NewStreamDialerFunc)
+func (p *ExtensibleProvider[ObjectType]) ensureBuildersMap() map[string]BuildFunc[ObjectType] {
+	if p.builders == nil {
+		p.builders = make(map[string]BuildFunc[ObjectType])
 	}
+	return p.builders
+}
 
-	if _, found := p.sdBuilders[subtype]; found {
-		return fmt.Errorf("config parser %v for StreamDialer added twice", subtype)
-	}
-	p.sdBuilders[subtype] = newDialer
-	return nil
+// RegisterType will register a factory for the given subtype.
+func (p *ExtensibleProvider[ObjectType]) RegisterType(subtype string, newInstance BuildFunc[ObjectType]) {
+	p.ensureBuildersMap()[subtype] = newInstance
 }
 
-// RegisterPacketDialerType will register a wrapper for packet dialers under the given subtype.
-func (p *ConfigToDialer) RegisterPacketDialerType(subtype string, newDialer NewPacketDialerFunc) error {
-	if p.pdBuilders == nil {
-		p.pdBuilders = make(map[string]NewPacketDialerFunc)
+// NewInstance creates a new instance of ObjectType according to the config.
+func (p *ExtensibleProvider[ObjectType]) NewInstance(ctx context.Context, config *Config) (ObjectType, error) {
+	var zero ObjectType
+	if config == nil {
+		if p.BaseInstance == zero {
+			return zero, errors.New("base instance is not configured")
+		}
+		return p.BaseInstance, nil
 	}
 
-	if _, found := p.pdBuilders[subtype]; found {
-		return fmt.Errorf("config parser %v for StreamDialer added twice", subtype)
+	newInstance, ok := p.ensureBuildersMap()[config.URL.Scheme]
+	if !ok {
+		return zero, fmt.Errorf("config type '%v' is not registered", config.URL.Scheme)
 	}
-	p.pdBuilders[subtype] = newDialer
-	return nil
+	return newInstance(ctx, config)
 }
 
-func parseConfig(configText string) ([]*url.URL, error) {
+// ParseConfig will parse a config given as a string and return the structured [Config].
+func ParseConfig(configText string) (*Config, error) {
 	parts := strings.Split(strings.TrimSpace(configText), "|")
 	if len(parts) == 1 && parts[0] == "" {
-		return []*url.URL{}, nil
+		return nil, nil
 	}
-	urls := make([]*url.URL, 0, len(parts))
+
+	var config *Config = nil
 	for _, part := range parts {
 		part = strings.TrimSpace(part)
 		if part == "" {
@@ -130,143 +106,7 @@ func parseConfig(configText string) ([]*url.URL, error) {
 		if err != nil {
 			return nil, fmt.Errorf("part is not a valid URL: %w", err)
 		}
-		urls = append(urls, url)
-	}
-	return urls, nil
-}
-
-// NewStreamDialer creates a [Dialer] according to transportConfig, using dialer as the
-// base [Dialer]. The given dialer must not be nil.
-func (p *ConfigToDialer) NewStreamDialer(transportConfig string) (transport.StreamDialer, error) {
-	parts, err := parseConfig(transportConfig)
-	if err != nil {
-		return nil, err
-	}
-	return p.newStreamDialer(parts)
-}
-
-// NewPacketDialer creates a [Dialer] according to transportConfig, using dialer as the
-// base [Dialer]. The given dialer must not be nil.
-func (p *ConfigToDialer) NewPacketDialer(transportConfig string) (transport.PacketDialer, error) {
-	parts, err := parseConfig(transportConfig)
-	if err != nil {
-		return nil, err
-	}
-	return p.newPacketDialer(parts)
-}
-
-func (p *ConfigToDialer) newStreamDialer(configParts []*url.URL) (transport.StreamDialer, error) {
-	if len(configParts) == 0 {
-		if p.BaseStreamDialer == nil {
-			return nil, fmt.Errorf("base StreamDialer must not be nil")
-		}
-		return p.BaseStreamDialer, nil
-	}
-	thisURL := configParts[len(configParts)-1]
-	innerConfig := configParts[:len(configParts)-1]
-	newDialer, ok := p.sdBuilders[thisURL.Scheme]
-	if !ok {
-		return nil, fmt.Errorf("config scheme '%v' is not supported for Stream Dialers", thisURL.Scheme)
-	}
-	newSD := func() (transport.StreamDialer, error) {
-		return p.newStreamDialer(innerConfig)
-	}
-	newPD := func() (transport.PacketDialer, error) {
-		return p.newPacketDialer(innerConfig)
-	}
-	return newDialer(newSD, newPD, thisURL)
-}
-
-func (p *ConfigToDialer) newPacketDialer(configParts []*url.URL) (transport.PacketDialer, error) {
-	if len(configParts) == 0 {
-		if p.BasePacketDialer == nil {
-			return nil, fmt.Errorf("base PacketDialer must not be nil")
-		}
-		return p.BasePacketDialer, nil
-	}
-	thisURL := configParts[len(configParts)-1]
-	innerConfig := configParts[:len(configParts)-1]
-	newDialer, ok := p.pdBuilders[thisURL.Scheme]
-	if !ok {
-		return nil, fmt.Errorf("config scheme '%v' is not supported for Packet Dialers", thisURL.Scheme)
-	}
-	newSD := func() (transport.StreamDialer, error) {
-		return p.newStreamDialer(innerConfig)
-	}
-	newPD := func() (transport.PacketDialer, error) {
-		return p.newPacketDialer(innerConfig)
-	}
-	return newDialer(newSD, newPD, thisURL)
-}
-
-// NewpacketListener creates a new [transport.PacketListener] according to the given config,
-// the config must contain only one "ss://" segment.
-// TODO: make NewPacketListener configurable.
-func NewPacketListener(transportConfig string) (transport.PacketListener, error) {
-	parts, err := parseConfig(transportConfig)
-	if err != nil {
-		return nil, err
-	}
-	if len(parts) == 0 {
-		return nil, errors.New("config is required")
-	}
-	if len(parts) > 1 {
-		return nil, errors.New("multi-part config is not supported")
-	}
-
-	url := parts[0]
-	// Please keep scheme list sorted.
-	switch strings.ToLower(url.Scheme) {
-	case "ss":
-		// TODO: support nested dialer, the last part must be "ss://"
-		return newShadowsocksPacketListenerFromURL(url)
-	default:
-		return nil, fmt.Errorf("config scheme '%v' is not supported", url.Scheme)
-	}
-}
-
-func SanitizeConfig(transportConfig string) (string, error) {
-	parts, err := parseConfig(transportConfig)
-	if err != nil {
-		return "", err
-	}
-
-	// Do nothing if the config is empty
-	if len(parts) == 0 {
-		return "", nil
-	}
-
-	// Iterate through each part
-	textParts := make([]string, len(parts))
-	for i, u := range parts {
-		scheme := strings.ToLower(u.Scheme)
-		switch scheme {
-		case "ss":
-			textParts[i], err = sanitizeShadowsocksURL(u)
-			if err != nil {
-				return "", err
-			}
-		case "socks5":
-			textParts[i], err = sanitizeSocks5URL(u)
-			if err != nil {
-				return "", err
-			}
-		case "override", "split", "tls", "tlsfrag":
-			// No sanitization needed
-			textParts[i] = u.String()
-		default:
-			textParts[i] = scheme + "://UNKNOWN"
-		}
-	}
-	// Join the parts back into a string
-	return strings.Join(textParts, "|"), nil
-}
-
-func sanitizeSocks5URL(u *url.URL) (string, error) {
-	const redactedPlaceholder = "REDACTED"
-	if u.User != nil {
-		u.User = url.User(redactedPlaceholder)
-		return u.String(), nil
+		config = &Config{URL: *url, BaseConfig: config}
 	}
-	return u.String(), nil
+	return config, nil
 }

x/configurl/dns.go

@@ -27,16 +27,46 @@ import (
 	"golang.org/x/net/dns/dnsmessage"
 )
 
-func wrapStreamDialerWithDO53(innerSD func() (transport.StreamDialer, error), innerPD func() (transport.PacketDialer, error), configURL *url.URL) (transport.StreamDialer, error) {
-	sd, err := innerSD()
-	if err != nil {
-		return nil, err
-	}
-	pd, err := innerPD()
-	if err != nil {
-		return nil, err
-	}
-	query := configURL.Opaque
+func registerDO53StreamDialer(r TypeRegistry[transport.StreamDialer], typeID string, newSD BuildFunc[transport.StreamDialer], newPD BuildFunc[transport.PacketDialer]) {
+	r.RegisterType(typeID, func(ctx context.Context, config *Config) (transport.StreamDialer, error) {
+		if config == nil {
+			return nil, fmt.Errorf("emtpy do53 config")
+		}
+		sd, err := newSD(ctx, config.BaseConfig)
+		if err != nil {
+			return nil, err
+		}
+		pd, err := newPD(ctx, config.BaseConfig)
+		if err != nil {
+			return nil, err
+		}
+		resolver, err := newDO53Resolver(config.URL, sd, pd)
+		if err != nil {
+			return nil, err
+		}
+		return dns.NewStreamDialer(resolver, sd)
+	})
+}
+
+func registerDOHStreamDialer(r TypeRegistry[transport.StreamDialer], typeID string, newSD BuildFunc[transport.StreamDialer]) {
+	r.RegisterType(typeID, func(ctx context.Context, config *Config) (transport.StreamDialer, error) {
+		if config == nil {
+			return nil, fmt.Errorf("emtpy doh config")
+		}
+		sd, err := newSD(ctx, config.BaseConfig)
+		if err != nil {
+			return nil, err
+		}
+		resolver, err := newDOHResolver(config.URL, sd)
+		if err != nil {
+			return nil, err
+		}
+		return dns.NewStreamDialer(resolver, sd)
+	})
+}
+
+func newDO53Resolver(config url.URL, sd transport.StreamDialer, pd transport.PacketDialer) (dns.Resolver, error) {
+	query := config.Opaque
 	values, err := url.ParseQuery(query)
 	if err != nil {
 		return nil, err
@@ -75,19 +105,15 @@ func wrapStreamDialerWithDO53(innerSD func() (transport.StreamDialer, error), in
 		// See https://datatracker.ietf.org/doc/html/rfc1123#page-75.
 		return tcpResolver.Query(ctx, q)
 	})
-	return dns.NewStreamDialer(resolver, sd)
+	return resolver, nil
 }
 
-func wrapStreamDialerWithDOH(innerSD func() (transport.StreamDialer, error), innerPD func() (transport.PacketDialer, error), configURL *url.URL) (transport.StreamDialer, error) {
-	query := configURL.Opaque
+func newDOHResolver(config url.URL, sd transport.StreamDialer) (dns.Resolver, error) {
+	query := config.Opaque
 	values, err := url.ParseQuery(query)
 	if err != nil {
 		return nil, err
 	}
-	sd, err := innerSD()
-	if err != nil {
-		return nil, err
-	}
 
 	var name, address string
 	for key, values := range values {
@@ -119,6 +145,5 @@ func wrapStreamDialerWithDOH(innerSD func() (transport.StreamDialer, error), inn
 		port = "443"
 	}
 	dohURL := url.URL{Scheme: "https", Host: net.JoinHostPort(name, port), Path: "/dns-query"}
-	resolver := dns.NewHTTPSResolver(sd, address, dohURL.String())
-	return dns.NewStreamDialer(resolver, sd)
+	return dns.NewHTTPSResolver(sd, address, dohURL.String()), nil
 }