local-dns remote-dns-addr will have default port 53

fixes #683

Cargo.lock

@@ -1623,7 +1623,7 @@ dependencies = [
 
 [[package]]
 name = "shadowsocks-rust"
-version = "1.12.1"
+version = "1.12.2"
 dependencies = [
  "build-time",
  "byte_string",

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "shadowsocks-rust"
-version = "1.12.1"
+version = "1.12.2"
 authors = ["Shadowsocks Contributors"]
 description = "shadowsocks is a fast tunnel proxy that helps you bypass firewalls."
 repository = "https://github.com/shadowsocks/shadowsocks-rust"

bin/sslocal.rs

@@ -329,7 +329,25 @@ fn main() {
 
             #[cfg(feature = "local-dns")]
             {
-                use shadowsocks_service::local::dns::NameServerAddr;
+                use shadowsocks_service::{local::dns::NameServerAddr, shadowsocks::relay::socks5::AddressError};
+                use std::net::SocketAddr;
+
+                #[inline]
+                fn parse_remote_dns_addr(a: &str) -> Result<Address, AddressError> {
+                    if let Ok(ip) = a.parse::<IpAddr>() {
+                        return Ok(Address::SocketAddress(SocketAddr::new(ip, 53)));
+                    }
+
+                    if let Ok(saddr) = a.parse::<SocketAddr>() {
+                        return Ok(Address::SocketAddress(saddr));
+                    }
+
+                    if a.find(':').is_some() {
+                        a.parse::<Address>()
+                    } else {
+                        Ok(Address::DomainNameAddress(a.to_owned(), 53))
+                    }
+                }
 
                 if let Some(local_dns_addr) = matches.value_of("LOCAL_DNS_ADDR") {
                     let addr = local_dns_addr.parse::<NameServerAddr>().expect("local dns address");
@@ -337,7 +355,7 @@ fn main() {
                 }
 
                 if let Some(remote_dns_addr) = matches.value_of("REMOTE_DNS_ADDR") {
-                    let addr = remote_dns_addr.parse::<Address>().expect("remote dns address");
+                    let addr = parse_remote_dns_addr(remote_dns_addr).expect("remote dns address");
                     local_config.remote_dns_addr = Some(addr);
                 }
             }

crates/shadowsocks-service/src/local/dns/config.rs

@@ -4,7 +4,7 @@
 use std::{convert::Infallible, path::PathBuf};
 use std::{
     fmt::{self, Display},
-    net::SocketAddr,
+    net::{IpAddr, SocketAddr},
     str::FromStr,
 };
 
@@ -31,6 +31,10 @@ impl FromStr for NameServerAddr {
     type Err = NameServerAddrError;
 
     fn from_str(s: &str) -> Result<Self, Self::Err> {
+        if let Ok(ip) = s.parse::<IpAddr>() {
+            return Ok(NameServerAddr::SocketAddr(SocketAddr::new(ip, 53)));
+        }
+
         match s.parse::<SocketAddr>() {
             Ok(addr) => Ok(NameServerAddr::SocketAddr(addr)),
             #[cfg(unix)]