Add client and service

client.go

@@ -0,0 +1,104 @@
+package shadowtls
+
+import (
+	"context"
+	"crypto/hmac"
+	"crypto/sha1"
+	"encoding/hex"
+	"net"
+	"os"
+
+	"github.com/sagernet/sing/common/debug"
+	E "github.com/sagernet/sing/common/exceptions"
+	"github.com/sagernet/sing/common/logger"
+	M "github.com/sagernet/sing/common/metadata"
+	N "github.com/sagernet/sing/common/network"
+)
+
+type ClientConfig struct {
+	Version      int
+	Password     string
+	Server       M.Socksaddr
+	Dialer       N.Dialer
+	TLSHandshake TLSHandshakeFunc
+	Logger       logger.ContextLogger
+}
+
+type Client struct {
+	version      int
+	password     string
+	server       M.Socksaddr
+	dialer       N.Dialer
+	tlsHandshake TLSHandshakeFunc
+	logger       logger.ContextLogger
+}
+
+func NewClient(config ClientConfig) (*Client, error) {
+	client := &Client{
+		version:      config.Version,
+		password:     config.Password,
+		server:       config.Server,
+		dialer:       config.Dialer,
+		tlsHandshake: config.TLSHandshake,
+		logger:       config.Logger,
+	}
+	if !client.server.IsValid() || client.dialer == nil || client.tlsHandshake == nil {
+		return nil, os.ErrInvalid
+	}
+	switch client.version {
+	case 1, 2, 3:
+	default:
+		return nil, E.New("unknown protocol version: ", client.version)
+	}
+	if client.dialer == nil {
+		client.dialer = N.SystemDialer
+	}
+	return client, nil
+}
+
+func (c *Client) DialContext(ctx context.Context) (net.Conn, error) {
+	conn, err := c.dialer.DialContext(ctx, N.NetworkTCP, c.server)
+	if err != nil {
+		return nil, err
+	}
+	switch c.version {
+	default:
+		fallthrough
+	case 1:
+		err = c.tlsHandshake(ctx, conn, nil)
+		if err != nil {
+			return nil, err
+		}
+		c.logger.TraceContext(ctx, "clint handshake finished")
+		return conn, nil
+	case 2:
+		hashConn := newHashReadConn(conn, c.password)
+		err = c.tlsHandshake(ctx, hashConn, nil)
+		if err != nil {
+			return nil, err
+		}
+		c.logger.TraceContext(ctx, "clint handshake finished")
+		return newClientConn(hashConn), nil
+	case 3:
+		stream := newStreamWrapper(conn, c.password)
+		err = c.tlsHandshake(ctx, stream, generateSessionID(c.password))
+		if err != nil {
+			return nil, err
+		}
+		c.logger.TraceContext(ctx, "handshake success")
+		authorized, serverRandom, readHMAC := stream.Authorized()
+		if !authorized {
+			return nil, E.New("traffic hijacked or TLS1.3 is not supported")
+		}
+		if debug.Enabled {
+			c.logger.TraceContext(ctx, "authorized, server random extracted: ", hex.EncodeToString(serverRandom))
+		}
+		hmacAdd := hmac.New(sha1.New, []byte(c.password))
+		hmacAdd.Write(serverRandom)
+		hmacAdd.Write([]byte("C"))
+		hmacVerify := hmac.New(sha1.New, []byte(c.password))
+		hmacVerify.Write(serverRandom)
+		hmacVerify.Write([]byte("S"))
+		return newVerifiedConn(conn, hmacAdd, hmacVerify, readHMAC), nil
+	}
+}