Add bind_reusablemethod to UdpSocket

src/libstd/io/net/udp.rs

@@ -71,6 +71,16 @@ impl UdpSocket {
         })
     }
 
+    /// Creates a UDP socket from the given address with `SO_REUSEADDR` set to true.
+    ///
+    /// Address type can be any implementor of `ToSocketAddr` trait. See its
+    /// documentation for concrete examples.
+    pub fn bind_reusable<A: ToSocketAddr>(addr: A) -> IoResult<UdpSocket> {
+        super::with_addresses(addr, |addr| {
+            UdpSocketImp::bind_reusable(addr).map(|s| UdpSocket { inner: s })
+        })
+    }
+
     /// Receives data from the socket. On success, returns the number of bytes
     /// read and the address from whence the data came.
     pub fn recv_from(&mut self, buf: &mut [u8]) -> IoResult<(uint, SocketAddr)> {

src/libstd/sys/common/net.rs

@@ -809,6 +809,28 @@ impl UdpSocket {
         }
     }
 
+    pub fn bind_reusable(addr: SocketAddr) -> IoResult<UdpSocket> {
+        sys::init_net();
+
+        let fd = try!(socket(addr, libc::SOCK_DGRAM));
+        let ret = UdpSocket {
+            inner: Arc::new(Inner::new(fd)),
+            read_deadline: 0,
+            write_deadline: 0,
+        };
+
+        setsockopt(fd, libc::SOL_SOCKET, libc::SO_REUSEADDR, true as libc::c_int).unwrap();
+
+        let mut storage = unsafe { mem::zeroed() };
+        let len = addr_to_sockaddr(addr, &mut storage);
+        let addrp = &storage as *const _ as *const libc::sockaddr;
+
+        match unsafe { libc::bind(fd, addrp, len) } {
+            -1 => Err(last_error()),
+            _ => Ok(ret),
+        }
+    }
+
     pub fn fd(&self) -> sock_t { self.inner.fd }
 
     pub fn set_broadcast(&mut self, on: bool) -> IoResult<()> {