From 6464f3748bdbe061d22f5bd1307c30f83c0d2ea4 Mon Sep 17 00:00:00 2001
From: spyophobia <76800505+spyophobia@users.noreply.github.com>
Date: Thu, 31 Aug 2023 17:39:24 +0800
Subject: [PATCH] local DNS uses mode `tcp_and_udp` by default

- Fixes #1281
---
 crates/shadowsocks-service/src/config.rs | 29 ++++++++++++++++--------
 1 file changed, 19 insertions(+), 10 deletions(-)

diff --git a/crates/shadowsocks-service/src/config.rs b/crates/shadowsocks-service/src/config.rs
index 4112a8d1f706..e44a9e9d504b 100644
--- a/crates/shadowsocks-service/src/config.rs
+++ b/crates/shadowsocks-service/src/config.rs
@@ -66,14 +66,7 @@ use serde::{Deserialize, Serialize};
 use shadowsocks::relay::socks5::Address;
 use shadowsocks::{
     config::{
-        ManagerAddr,
-        Mode,
-        ReplayAttackPolicy,
-        ServerAddr,
-        ServerConfig,
-        ServerUser,
-        ServerUserManager,
-        ServerWeight,
+        ManagerAddr, Mode, ReplayAttackPolicy, ServerAddr, ServerConfig, ServerUser, ServerUserManager, ServerWeight,
     },
     crypto::CipherKind,
     plugin::PluginConfig,
@@ -891,12 +884,20 @@ pub struct LocalConfig {
 impl LocalConfig {
     /// Create a new `LocalConfig`
     pub fn new(protocol: ProtocolType) -> LocalConfig {
+        // DNS server runs in `TcpAndUdp` mode by default to maintain backwards compatibility
+        // see https://github.com/shadowsocks/shadowsocks-rust/issues/1281
+        let mode = match protocol {
+            #[cfg(feature = "local-dns")]
+            ProtocolType::Dns => Mode::TcpAndUdp,
+            _ => Mode::TcpOnly,
+        };
+
         LocalConfig {
             addr: None,
 
             protocol,
 
-            mode: Mode::TcpOnly,
+            mode,
             udp_addr: None,
 
             #[cfg(feature = "local-tunnel")]
@@ -1456,7 +1457,15 @@ impl Config {
                                 }
                             },
                             None => {
-                                local_config.mode = global_mode;
+                                // DNS server runs in `TcpAndUdp` mode by default to maintain backwards compatibility
+                                // see https://github.com/shadowsocks/shadowsocks-rust/issues/1281
+                                let mode = match protocol {
+                                    #[cfg(feature = "local-dns")]
+                                    ProtocolType::Dns => Mode::TcpAndUdp,
+                                    _ => global_mode,
+                                };
+
+                                local_config.mode = mode;
                             }
                         }