Adapt new shadowsocks library.

1. Modify ss/ssu handler and connector
2. Add users to metadata of ss and ssu handler

handler/ss/udp/metadata.go

@@ -4,6 +4,7 @@ import (
 	"time"
 
 	mdata "github.com/go-gost/core/metadata"
+	"github.com/go-gost/go-shadowsocks2/core"
 	mdutil "github.com/go-gost/x/metadata/util"
 )
 
@@ -15,6 +16,8 @@ type metadata struct {
 	key           string
 	readTimeout   time.Duration
 	udpBufferSize int
+
+	users []core.UserConfig
 }
 
 func (h *ssuHandler) parseMetadata(md mdata.Metadata) (err error) {
@@ -23,5 +26,13 @@ func (h *ssuHandler) parseMetadata(md mdata.Metadata) (err error) {
 	h.md.readTimeout = mdutil.GetDuration(md, "readTimeout")
 	h.md.udpBufferSize = mdutil.GetInt(md, "udpBufferSize", "udp.bufferSize")
 
+	usersMap := mdutil.GetStringMapString(md, "users")
+	for name, pass := range usersMap {
+		h.md.users = append(h.md.users, core.UserConfig{
+			Name:     name,
+			Password: pass,
+		})
+	}
+
 	return
 }