diff --git a/crates/shadowsocks-service/src/dns/mod.rs b/crates/shadowsocks-service/src/dns/mod.rs
index 08d70a2061c2..e1f25eb715bb 100644
--- a/crates/shadowsocks-service/src/dns/mod.rs
+++ b/crates/shadowsocks-service/src/dns/mod.rs
@@ -6,7 +6,12 @@ use shadowsocks::{dns_resolver::DnsResolver, net::ConnectOpts};
 use crate::config::DnsConfig;
 
 #[allow(unused_variables, dead_code)]
-pub async fn build_dns_resolver(dns: DnsConfig, ipv6_first: bool, dns_cache_size: Option<usize>, connect_opts: &ConnectOpts) -> Option<DnsResolver> {
+pub async fn build_dns_resolver(
+    dns: DnsConfig,
+    ipv6_first: bool,
+    dns_cache_size: Option<usize>,
+    connect_opts: &ConnectOpts,
+) -> Option<DnsResolver> {
     match dns {
         DnsConfig::System => {
             #[cfg(feature = "trust-dns")]
@@ -41,18 +46,20 @@ pub async fn build_dns_resolver(dns: DnsConfig, ipv6_first: bool, dns_cache_size
             None
         }
         #[cfg(feature = "trust-dns")]
-        DnsConfig::TrustDns(dns) => match DnsResolver::trust_dns_resolver(dns, dns_cache_size, connect_opts.clone()).await {
-            Ok(r) => Some(r),
-            Err(err) => {
-                use log::warn;
+        DnsConfig::TrustDns(dns) => {
+            match DnsResolver::trust_dns_resolver(dns, dns_cache_size, connect_opts.clone()).await {
+                Ok(r) => Some(r),
+                Err(err) => {
+                    use log::warn;
 
-                warn!(
-                    "initialize trust-dns DNS resolver failed, fallback to default system resolver, error: {}",
-                    err
-                );
-                None
+                    warn!(
+                        "initialize trust-dns DNS resolver failed, fallback to default system resolver, error: {}",
+                        err
+                    );
+                    None
+                }
             }
-        },
+        }
         #[cfg(feature = "local-dns")]
         DnsConfig::LocalDns(ns) => {
             use crate::local::dns::dns_resolver::DnsResolver as LocalDnsResolver;
diff --git a/crates/shadowsocks-service/src/local/mod.rs b/crates/shadowsocks-service/src/local/mod.rs
index d3d48cecc386..942488cd1311 100644
--- a/crates/shadowsocks-service/src/local/mod.rs
+++ b/crates/shadowsocks-service/src/local/mod.rs
@@ -165,7 +165,14 @@ impl Server {
         accept_opts.tcp.mptcp = config.mptcp;
         context.set_accept_opts(accept_opts);
 
-        if let Some(resolver) = build_dns_resolver(config.dns, config.ipv6_first, config.dns_cache_size, context.connect_opts_ref()).await {
+        if let Some(resolver) = build_dns_resolver(
+            config.dns,
+            config.ipv6_first,
+            config.dns_cache_size,
+            context.connect_opts_ref(),
+        )
+        .await
+        {
             context.set_dns_resolver(Arc::new(resolver));
         }
 
diff --git a/crates/shadowsocks-service/src/local/socks/server/mod.rs b/crates/shadowsocks-service/src/local/socks/server/mod.rs
index e868929d3648..1ccfd3b0bd19 100644
--- a/crates/shadowsocks-service/src/local/socks/server/mod.rs
+++ b/crates/shadowsocks-service/src/local/socks/server/mod.rs
@@ -12,6 +12,7 @@ use self::socks5::Socks5UdpServer;
 
 use super::config::Socks5AuthConfig;
 
+#[allow(clippy::module_inception)]
 mod server;
 #[cfg(feature = "local-socks4")]
 mod socks4;
diff --git a/crates/shadowsocks-service/src/local/tun/virt_device.rs b/crates/shadowsocks-service/src/local/tun/virt_device.rs
index 887024c70f31..1dafb66a838f 100644
--- a/crates/shadowsocks-service/src/local/tun/virt_device.rs
+++ b/crates/shadowsocks-service/src/local/tun/virt_device.rs
@@ -22,6 +22,7 @@ pub struct VirtTunDevice {
 }
 
 impl VirtTunDevice {
+    #[allow(clippy::type_complexity)]
     pub fn new(
         capabilities: DeviceCapabilities,
     ) -> (
@@ -57,7 +58,7 @@ impl Device for VirtTunDevice {
     type RxToken<'a> = VirtRxToken<'a>;
     type TxToken<'a> = VirtTxToken<'a>;
 
-    fn receive<'a>(&'a mut self, _timestamp: Instant) -> Option<(Self::RxToken<'a>, Self::TxToken<'a>)> {
+    fn receive(&mut self, _timestamp: Instant) -> Option<(Self::RxToken<'_>, Self::TxToken<'_>)> {
         if let Ok(buffer) = self.in_buf.try_recv() {
             let rx = Self::RxToken {
                 buffer,
@@ -70,7 +71,7 @@ impl Device for VirtTunDevice {
         None
     }
 
-    fn transmit<'a>(&'a mut self, _timestamp: Instant) -> Option<Self::TxToken<'a>> {
+    fn transmit(&mut self, _timestamp: Instant) -> Option<Self::TxToken<'_>> {
         return Some(VirtTxToken(self));
     }
 
diff --git a/crates/shadowsocks-service/src/manager/mod.rs b/crates/shadowsocks-service/src/manager/mod.rs
index 7dcea2d260a4..1aea53824088 100644
--- a/crates/shadowsocks-service/src/manager/mod.rs
+++ b/crates/shadowsocks-service/src/manager/mod.rs
@@ -64,7 +64,9 @@ pub async fn run(config: Config) -> io::Result<()> {
     accept_opts.tcp.keepalive = config.keep_alive.or(Some(SERVER_DEFAULT_KEEPALIVE_TIMEOUT));
     accept_opts.tcp.mptcp = config.mptcp;
 
-    if let Some(resolver) = build_dns_resolver(config.dns, config.ipv6_first, config.dns_cache_size, &connect_opts).await {
+    if let Some(resolver) =
+        build_dns_resolver(config.dns, config.ipv6_first, config.dns_cache_size, &connect_opts).await
+    {
         manager_builder.set_dns_resolver(Arc::new(resolver));
     }
     manager_builder.set_ipv6_first(config.ipv6_first);
diff --git a/crates/shadowsocks-service/src/manager/server.rs b/crates/shadowsocks-service/src/manager/server.rs
index c518fa3886d3..f281ef9cbe50 100644
--- a/crates/shadowsocks-service/src/manager/server.rs
+++ b/crates/shadowsocks-service/src/manager/server.rs
@@ -373,8 +373,8 @@ impl Manager {
 
         let server_config_path = self.server_config_path(port);
 
-        let _ = fs::remove_file(&pid_path);
-        let _ = fs::remove_file(&server_config_path);
+        let _ = fs::remove_file(pid_path);
+        let _ = fs::remove_file(server_config_path);
     }
 
     #[cfg(unix)]
diff --git a/crates/shadowsocks-service/src/server/udprelay.rs b/crates/shadowsocks-service/src/server/udprelay.rs
index e0da9f05e2b7..cb5cea3129bc 100644
--- a/crates/shadowsocks-service/src/server/udprelay.rs
+++ b/crates/shadowsocks-service/src/server/udprelay.rs
@@ -194,7 +194,8 @@ impl UdpServer {
 
                         if (otx
                             .send((peer_addr, target_addr, control, Bytes::copy_from_slice(&buffer[..n])))
-                            .await).is_err()
+                            .await)
+                            .is_err()
                         {
                             // If Result is error, the channel receiver is closed. We should exit the task.
                             break;
diff --git a/crates/shadowsocks/src/dns_resolver/resolver.rs b/crates/shadowsocks/src/dns_resolver/resolver.rs
index 620e55b8434d..8ee7fbf2da33 100644
--- a/crates/shadowsocks/src/dns_resolver/resolver.rs
+++ b/crates/shadowsocks/src/dns_resolver/resolver.rs
@@ -227,7 +227,10 @@ impl DnsResolver {
     ///
     /// On *nix system, it will try to read configurations from `/etc/resolv.conf`.
     #[cfg(feature = "trust-dns")]
-    pub async fn trust_dns_system_resolver(dns_cache_size: Option<usize>, connect_opts: ConnectOpts) -> io::Result<DnsResolver> {
+    pub async fn trust_dns_system_resolver(
+        dns_cache_size: Option<usize>,
+        connect_opts: ConnectOpts,
+    ) -> io::Result<DnsResolver> {
         use super::trust_dns_resolver::create_resolver;
 
         let resolver = create_resolver(None, dns_cache_size, connect_opts.clone()).await?;
@@ -258,9 +261,15 @@ impl DnsResolver {
 
     /// Use trust-dns DNS resolver (with DNS cache)
     #[cfg(feature = "trust-dns")]
-    pub async fn trust_dns_resolver(dns: ResolverConfig, dns_cache_size: Option<usize>, connect_opts: ConnectOpts) -> io::Result<DnsResolver> {
+    pub async fn trust_dns_resolver(
+        dns: ResolverConfig,
+        dns_cache_size: Option<usize>,
+        connect_opts: ConnectOpts,
+    ) -> io::Result<DnsResolver> {
         use super::trust_dns_resolver::create_resolver;
-        Ok(DnsResolver::TrustDns(create_resolver(Some(dns), dns_cache_size, connect_opts).await?))
+        Ok(DnsResolver::TrustDns(
+            create_resolver(Some(dns), dns_cache_size, connect_opts).await?,
+        ))
     }
 
     /// Custom DNS resolver
diff --git a/crates/shadowsocks/src/dns_resolver/trust_dns_resolver.rs b/crates/shadowsocks/src/dns_resolver/trust_dns_resolver.rs
index eb5ad474e156..2fc27f7dce51 100644
--- a/crates/shadowsocks/src/dns_resolver/trust_dns_resolver.rs
+++ b/crates/shadowsocks/src/dns_resolver/trust_dns_resolver.rs
@@ -99,7 +99,11 @@ pub type ShadowDnsConnectionProvider = GenericConnector<ShadowDnsRuntimeProvider
 pub type DnsResolver = AsyncResolver<ShadowDnsConnectionProvider>;
 
 /// Create a `trust-dns` asynchronous DNS resolver
-pub async fn create_resolver(dns: Option<ResolverConfig>, dns_cache_size: Option<usize>, connect_opts: ConnectOpts) -> ResolveResult<DnsResolver> {
+pub async fn create_resolver(
+    dns: Option<ResolverConfig>,
+    dns_cache_size: Option<usize>,
+    connect_opts: ConnectOpts,
+) -> ResolveResult<DnsResolver> {
     // Customized dns resolution
     match dns {
         Some(conf) => {
@@ -108,7 +112,9 @@ pub async fn create_resolver(dns: Option<ResolverConfig>, dns_cache_size: Option
             // Since we want to use Happy Eyeballs to connect to both IPv4 and IPv6 addresses, we need both A and AAAA records.
             resolver_opts.ip_strategy = LookupIpStrategy::Ipv4AndIpv6;
 
-            if let Some(size) = dns_cache_size { resolver_opts.cache_size = size }
+            if let Some(size) = dns_cache_size {
+                resolver_opts.cache_size = size
+            }
 
             trace!(
                 "initializing DNS resolver with config {:?} opts {:?}",
diff --git a/crates/shadowsocks/src/net/sys/unix/bsd/freebsd.rs b/crates/shadowsocks/src/net/sys/unix/bsd/freebsd.rs
index 812e29c3792b..180154cdb564 100644
--- a/crates/shadowsocks/src/net/sys/unix/bsd/freebsd.rs
+++ b/crates/shadowsocks/src/net/sys/unix/bsd/freebsd.rs
@@ -1,5 +1,6 @@
 use std::{
-    io, mem,
+    io,
+    mem,
     net::{IpAddr, Ipv4Addr, Ipv6Addr, SocketAddr},
     os::unix::io::{AsRawFd, RawFd},
     pin::Pin,
@@ -20,7 +21,9 @@ use tokio_tfo::TfoStream;
 use crate::net::{
     sys::{set_common_sockopt_after_connect, set_common_sockopt_for_connect, socket_bind_dual_stack},
     udp::{BatchRecvMessage, BatchSendMessage},
-    AcceptOpts, AddrFamily, ConnectOpts,
+    AcceptOpts,
+    AddrFamily,
+    ConnectOpts,
 };
 
 /// A `TcpStream` that supports TFO (TCP Fast Open)
diff --git a/crates/shadowsocks/src/net/sys/unix/bsd/macos.rs b/crates/shadowsocks/src/net/sys/unix/bsd/macos.rs
index eac9c8b78fbc..a730bd9c35b1 100644
--- a/crates/shadowsocks/src/net/sys/unix/bsd/macos.rs
+++ b/crates/shadowsocks/src/net/sys/unix/bsd/macos.rs
@@ -21,7 +21,9 @@ use tokio_tfo::TfoStream;
 use crate::net::{
     sys::{set_common_sockopt_after_connect, set_common_sockopt_for_connect, socket_bind_dual_stack},
     udp::{BatchRecvMessage, BatchSendMessage},
-    AcceptOpts, AddrFamily, ConnectOpts,
+    AcceptOpts,
+    AddrFamily,
+    ConnectOpts,
 };
 
 /// A `TcpStream` that supports TFO (TCP Fast Open)
diff --git a/crates/shadowsocks/src/net/sys/unix/linux/mod.rs b/crates/shadowsocks/src/net/sys/unix/linux/mod.rs
index 1122f041d128..07acde426613 100644
--- a/crates/shadowsocks/src/net/sys/unix/linux/mod.rs
+++ b/crates/shadowsocks/src/net/sys/unix/linux/mod.rs
@@ -1,5 +1,6 @@
 use std::{
-    io, mem,
+    io,
+    mem,
     net::{IpAddr, Ipv4Addr, Ipv6Addr, SocketAddr},
     os::unix::io::{AsRawFd, FromRawFd, IntoRawFd, RawFd},
     pin::Pin,
@@ -21,7 +22,9 @@ use tokio_tfo::TfoStream;
 use crate::net::{
     sys::{set_common_sockopt_after_connect, set_common_sockopt_for_connect, socket_bind_dual_stack},
     udp::{BatchRecvMessage, BatchSendMessage},
-    AcceptOpts, AddrFamily, ConnectOpts,
+    AcceptOpts,
+    AddrFamily,
+    ConnectOpts,
 };
 
 /// A `TcpStream` that supports TFO (TCP Fast Open)
diff --git a/crates/shadowsocks/src/plugin/mod.rs b/crates/shadowsocks/src/plugin/mod.rs
index 55ea2b0ec24f..b55f7c0b83a2 100644
--- a/crates/shadowsocks/src/plugin/mod.rs
+++ b/crates/shadowsocks/src/plugin/mod.rs
@@ -227,10 +227,8 @@ impl Drop for Plugin {
             }
         }
 
-        if !terminated {
-            if self.process.start_kill().is_ok() {
-                debug!("killed plugin process {:?}", self.process.id());
-            }
+        if !terminated && self.process.start_kill().is_ok() {
+            debug!("killed plugin process {:?}", self.process.id());
         }
     }
 }
diff --git a/crates/shadowsocks/src/relay/udprelay/proxy_socket.rs b/crates/shadowsocks/src/relay/udprelay/proxy_socket.rs
index 1ea9eb7d8827..812733048e04 100644
--- a/crates/shadowsocks/src/relay/udprelay/proxy_socket.rs
+++ b/crates/shadowsocks/src/relay/udprelay/proxy_socket.rs
@@ -458,6 +458,7 @@ impl ProxySocket {
     /// This function will use `recv_buf` to store intermediate data, so it has to be big enough to store the whole shadowsocks' packet
     ///
     /// It is recommended to allocate a buffer to have at least 65536 bytes.
+    #[allow(clippy::type_complexity)]
     pub async fn recv_from(&self, recv_buf: &mut [u8]) -> ProxySocketResult<(usize, SocketAddr, Address, usize)> {
         self.recv_from_with_ctrl(recv_buf)
             .await
@@ -469,6 +470,7 @@ impl ProxySocket {
     /// This function will use `recv_buf` to store intermediate data, so it has to be big enough to store the whole shadowsocks' packet
     ///
     /// It is recommended to allocate a buffer to have at least 65536 bytes.
+    #[allow(clippy::type_complexity)]
     pub async fn recv_from_with_ctrl(
         &self,
         recv_buf: &mut [u8],
@@ -502,6 +504,7 @@ impl ProxySocket {
 
     /// poll family functions.
     /// the recv_timeout is ignored.
+    #[allow(clippy::type_complexity)]
     pub fn poll_recv(
         &self,
         cx: &mut Context<'_>,
@@ -512,6 +515,7 @@ impl ProxySocket {
     }
 
     /// poll family functions
+    #[allow(clippy::type_complexity)]
     pub fn poll_recv_with_ctrl(
         &self,
         cx: &mut Context<'_>,
@@ -527,6 +531,8 @@ impl ProxySocket {
         }
     }
 
+    /// poll family functions
+    #[allow(clippy::type_complexity)]
     pub fn poll_recv_from(
         &self,
         cx: &mut Context<'_>,
@@ -536,6 +542,8 @@ impl ProxySocket {
             .map(|r| r.map(|(n, sa, a, rn, _)| (n, sa, a, rn)))
     }
 
+    /// poll family functions
+    #[allow(clippy::type_complexity)]
     pub fn poll_recv_from_with_ctrl(
         &self,
         cx: &mut Context<'_>,
@@ -550,6 +558,7 @@ impl ProxySocket {
         }
     }
 
+    /// poll family functions
     pub fn poll_recv_ready(&self, cx: &mut Context<'_>) -> Poll<ProxySocketResult<()>> {
         self.socket.poll_recv_ready(cx).map_err(|x| x.into())
     }
diff --git a/src/service/local.rs b/src/service/local.rs
index a7b0313e53b3..9780f55918ef 100644
--- a/src/service/local.rs
+++ b/src/service/local.rs
@@ -14,7 +14,12 @@ use shadowsocks_service::shadowsocks::relay::socks5::Address;
 use shadowsocks_service::{
     acl::AccessControl,
     config::{
-        read_variable_field_value, Config, ConfigType, LocalConfig, LocalInstanceConfig, ProtocolType,
+        read_variable_field_value,
+        Config,
+        ConfigType,
+        LocalConfig,
+        LocalInstanceConfig,
+        ProtocolType,
         ServerInstanceConfig,
     },
     local::{loadbalancing::PingBalancer, Server},
@@ -29,7 +34,8 @@ use shadowsocks_service::{
 use crate::logging;
 use crate::{
     config::{Config as ServiceConfig, RuntimeMode},
-    monitor, vparser,
+    monitor,
+    vparser,
 };
 
 #[cfg(feature = "local-dns")]
diff --git a/src/service/manager.rs b/src/service/manager.rs
index 895063170963..afb5171e53c3 100644
--- a/src/service/manager.rs
+++ b/src/service/manager.rs
@@ -24,7 +24,8 @@ use shadowsocks_service::{
 use crate::logging;
 use crate::{
     config::{Config as ServiceConfig, RuntimeMode},
-    monitor, vparser,
+    monitor,
+    vparser,
 };
 
 /// Defines command line options
diff --git a/src/service/server.rs b/src/service/server.rs
index 2bec03d6a03f..0b9213f79f46 100644
--- a/src/service/server.rs
+++ b/src/service/server.rs
@@ -22,7 +22,8 @@ use shadowsocks_service::{
 use crate::logging;
 use crate::{
     config::{Config as ServiceConfig, RuntimeMode},
-    monitor, vparser,
+    monitor,
+    vparser,
 };
 
 /// Defines command line options