Add password support for shadowsocks 2022 ciphers

protocol/shadowsocks/shadowimpl/fetcher.go

@@ -0,0 +1,56 @@
+package shadowimpl
+
+import (
+	"encoding/base64"
+	"io"
+	"strings"
+
+	"github.com/sagernet/sing/common"
+	E "github.com/sagernet/sing/common/exceptions"
+	"github.com/sagernet/sing/protocol/shadowsocks"
+	"github.com/sagernet/sing/protocol/shadowsocks/shadowaead"
+	"github.com/sagernet/sing/protocol/shadowsocks/shadowaead_2022"
+	"github.com/sagernet/sing/protocol/shadowsocks/shadowstream"
+)
+
+func FetchMethod(method string, key string, password string, secureRNG io.Reader) (shadowsocks.Method, error) {
+	if method == "none" {
+		return shadowsocks.NewNone(), nil
+	} else if common.Contains(shadowstream.List, method) {
+		var keyBytes []byte
+		if key != "" {
+			kb, err := base64.StdEncoding.DecodeString(key)
+			if err != nil {
+				return nil, E.Cause(err, "decode key")
+			}
+			keyBytes = kb
+		}
+		return shadowstream.New(method, keyBytes, password, secureRNG)
+	} else if common.Contains(shadowaead.List, method) {
+		var keyBytes []byte
+		if key != "" {
+			kb, err := base64.StdEncoding.DecodeString(key)
+			if err != nil {
+				return nil, E.Cause(err, "decode key")
+			}
+			keyBytes = kb
+		}
+		return shadowaead.New(method, keyBytes, password, secureRNG)
+	} else if common.Contains(shadowaead_2022.List, method) {
+		var pskList [][]byte
+		if key != "" {
+			keyStrList := strings.Split(key, ":")
+			pskList = make([][]byte, len(keyStrList))
+			for i, keyStr := range keyStrList {
+				kb, err := base64.StdEncoding.DecodeString(keyStr)
+				if err != nil {
+					return nil, E.Cause(err, "decode key")
+				}
+				pskList[i] = kb
+			}
+		}
+		return shadowaead_2022.New(method, pskList, password, secureRNG)
+	} else {
+		return nil, E.New("shadowsocks: unsupported method ", method)
+	}
+}