src: connection: Fix panic when DNS lookup fails

src/connection/mod.rs

@@ -102,3 +102,19 @@ pub fn connect<M: Message>(address: &str) -> io::Result<Box<dyn MavConnection<M>
         protocol_err
     }
 }
+
+/// Returns the socket address for the given address.
+pub(crate) fn get_socket_addr<T: std::net::ToSocketAddrs>(
+    address: T,
+) -> Result<std::net::SocketAddr, io::Error> {
+    let addr = match address.to_socket_addrs()?.next() {
+        Some(addr) => addr,
+        None => {
+            return Err(io::Error::new(
+                io::ErrorKind::Other,
+                "Host address lookup failed",
+            ));
+        }
+    };
+    Ok(addr)
+}

src/connection/tcp.rs

@@ -6,6 +6,8 @@ use std::net::{TcpListener, TcpStream};
 use std::sync::Mutex;
 use std::time::Duration;
 
+use super::get_socket_addr;
+
 /// TCP MAVLink connection
 
 pub fn select_protocol<M: Message>(
@@ -24,12 +26,9 @@ pub fn select_protocol<M: Message>(
 }
 
 pub fn tcpout<T: ToSocketAddrs>(address: T) -> io::Result<TcpConnection> {
-    let addr = address
-        .to_socket_addrs()
-        .unwrap()
-        .next()
-        .expect("Host address lookup failed.");
-    let socket = TcpStream::connect(&addr)?;
+    let addr = get_socket_addr(address)?;
+
+    let socket = TcpStream::connect(addr)?;
     socket.set_read_timeout(Some(Duration::from_millis(100)))?;
 
     Ok(TcpConnection {
@@ -43,12 +42,8 @@ pub fn tcpout<T: ToSocketAddrs>(address: T) -> io::Result<TcpConnection> {
 }
 
 pub fn tcpin<T: ToSocketAddrs>(address: T) -> io::Result<TcpConnection> {
-    let addr = address
-        .to_socket_addrs()
-        .unwrap()
-        .next()
-        .expect("Invalid address");
-    let listener = TcpListener::bind(&addr)?;
+    let addr = get_socket_addr(address)?;
+    let listener = TcpListener::bind(addr)?;
 
     //For now we only accept one incoming stream: this blocks until we get one
     for incoming in listener.incoming() {

src/connection/udp.rs

@@ -7,6 +7,8 @@ use std::net::{SocketAddr, UdpSocket};
 use std::str::FromStr;
 use std::sync::Mutex;
 
+use super::get_socket_addr;
+
 /// UDP MAVLink connection
 
 pub fn select_protocol<M: Message>(
@@ -27,35 +29,23 @@ pub fn select_protocol<M: Message>(
 }
 
 pub fn udpbcast<T: ToSocketAddrs>(address: T) -> io::Result<UdpConnection> {
-    let addr = address
-        .to_socket_addrs()
-        .unwrap()
-        .next()
-        .expect("Invalid address");
-    let socket = UdpSocket::bind(&SocketAddr::from_str("0.0.0.0:0").unwrap()).unwrap();
+    let addr = get_socket_addr(address)?;
+    let socket = UdpSocket::bind("0.0.0.0:0")?;
     socket
         .set_broadcast(true)
         .expect("Couldn't bind to broadcast address.");
     UdpConnection::new(socket, false, Some(addr))
 }
 
 pub fn udpout<T: ToSocketAddrs>(address: T) -> io::Result<UdpConnection> {
-    let addr = address
-        .to_socket_addrs()
-        .unwrap()
-        .next()
-        .expect("Invalid address");
-    let socket = UdpSocket::bind(&SocketAddr::from_str("0.0.0.0:0").unwrap())?;
+    let addr = get_socket_addr(address)?;
+    let socket = UdpSocket::bind("0.0.0.0:0")?;
     UdpConnection::new(socket, false, Some(addr))
 }
 
 pub fn udpin<T: ToSocketAddrs>(address: T) -> io::Result<UdpConnection> {
-    let addr = address
-        .to_socket_addrs()
-        .unwrap()
-        .next()
-        .expect("Invalid address");
-    let socket = UdpSocket::bind(&addr)?;
+    let addr = get_socket_addr(address)?;
+    let socket = UdpSocket::bind(addr)?;
     UdpConnection::new(socket, true, None)
 }