fix(ss): address review findings for PR #96 — nil guards, resource leaks, dead code

- Bump go-shadowsocks2 to v0.1.3 (new API symbols)
- Return error instead of nil when Target() is empty in TCP handler
- Reset wbuf unconditionally on write error to prevent unbounded growth
- Add nil guard on targetAddr before WriteTo to prevent panic
- Remove duplicate NewClientConfig call and dead ClientConfig literal
- Remove unused noDelay metadata field
- Fix buffer-size guard to catch negative values (len(b)==0 → bufSize<=0)
- Add address context to parse/session error messages

connector/ss/metadata.go

@@ -10,19 +10,16 @@ import (
 type metadata struct {
 	key            string
 	connectTimeout time.Duration
-	noDelay        bool
 }
 
 func (c *ssConnector) parseMetadata(md mdata.Metadata) (err error) {
 	const (
 		key            = "key"
 		connectTimeout = "timeout"
-		noDelay        = "nodelay"
 	)
 
 	c.md.key = mdutil.GetString(md, key)
 	c.md.connectTimeout = mdutil.GetDuration(md, connectTimeout)
-	c.md.noDelay = mdutil.GetBool(md, noDelay)
 
 	return
 }

connector/ss/udp/connector.go

@@ -58,13 +58,8 @@ func (c *ssuConnector) Init(md md.Metadata) (err error) {
 	}
 	clientConfig.UDPTimeout = time.Minute
 
-	tcpClientConfig, err := utils.NewClientConfig(method, password)
-	if err != nil {
-		return err
-	}
-
 	c.clientCfg = clientConfig
-	c.tcpClient = core.NewTCPClient(tcpClientConfig)
+	c.tcpClient = core.NewTCPClient(clientConfig)
 
 	return
 }
@@ -98,15 +93,11 @@ func (c *ssuConnector) Connect(ctx context.Context, conn net.Conn, network, addr
 	}
 	serverAddr, err := netip.ParseAddrPort(conn.RemoteAddr().String())
 	if err != nil {
-		return nil, err
+		return nil, fmt.Errorf("ss: parse remote addr %q: %w", conn.RemoteAddr().String(), err)
 	}
 	clientCfg := c.clientCfg
 	clientCfg.ServerAddr = serverAddr
-	client := core.NewUDPClient(core.ClientConfig{
-		Cipher:     clientCfg.Cipher,
-		ServerAddr: serverAddr,
-		UDPTimeout: time.Minute,
-	})
+	client := core.NewUDPClient(clientCfg)
 	if err := client.Init(); err != nil {
 		return nil, err
 	}