TcpListener::bind_to_port and related changes

src/liblibc/lib.rs

@@ -2318,6 +2318,7 @@ pub mod consts {
             pub const IP_DROP_MEMBERSHIP: c_int = 13;
             pub const IPV6_ADD_MEMBERSHIP: c_int = 5;
             pub const IPV6_DROP_MEMBERSHIP: c_int = 6;
+            pub const IPV6_V6ONLY: c_int = 27;
             pub const IP_TTL: c_int = 4;
             pub const IP_HDRINCL: c_int = 2;
 
@@ -3213,6 +3214,7 @@ pub mod consts {
             pub const IP_DROP_MEMBERSHIP: c_int = 36;
             pub const IPV6_ADD_MEMBERSHIP: c_int = 20;
             pub const IPV6_DROP_MEMBERSHIP: c_int = 21;
+            pub const IPV6_V6ONLY: c_int = 26;
 
             pub const TCP_NODELAY: c_int = 1;
             pub const SOL_SOCKET: c_int = 1;
@@ -3259,6 +3261,7 @@ pub mod consts {
             pub const IP_DROP_MEMBERSHIP: c_int = 36;
             pub const IPV6_ADD_MEMBERSHIP: c_int = 20;
             pub const IPV6_DROP_MEMBERSHIP: c_int = 21;
+            pub const IPV6_V6ONLY: c_int = 26;
 
             pub const TCP_NODELAY: c_int = 1;
             pub const SOL_SOCKET: c_int = 65535;
@@ -3749,6 +3752,7 @@ pub mod consts {
             pub const IP_DROP_MEMBERSHIP: c_int = 13;
             pub const IPV6_ADD_MEMBERSHIP: c_int = 12;
             pub const IPV6_DROP_MEMBERSHIP: c_int = 13;
+            pub const IPV6_V6ONLY: c_int = 27;
 
             pub const TCP_NODELAY: c_int = 1;
             pub const TCP_KEEPIDLE: c_int = 256;
@@ -4131,6 +4135,7 @@ pub mod consts {
             pub const IP_DROP_MEMBERSHIP: c_int = 13;
             pub const IPV6_ADD_MEMBERSHIP: c_int = 12; // don't exist
             pub const IPV6_DROP_MEMBERSHIP: c_int = 13; // don't exist
+            pub const IPV6_V6ONLY: c_int = 27;
 
             pub const TCP_NODELAY: c_int = 0x01;
             pub const SOL_SOCKET: c_int = 0xffff;
@@ -4528,6 +4533,7 @@ pub mod consts {
             pub const IP_DROP_MEMBERSHIP: c_int = 13;
             pub const IPV6_ADD_MEMBERSHIP: c_int = 12;
             pub const IPV6_DROP_MEMBERSHIP: c_int = 13;
+            pub const IPV6_V6ONLY: c_int = 27;
 
             pub const TCP_NODELAY: c_int = 0x01;
             pub const TCP_KEEPALIVE: c_int = 0x10;

src/libstd/net/tcp.rs

@@ -12,7 +12,7 @@ use prelude::v1::*;
 use io::prelude::*;
 
 use io;
-use net::{ToSocketAddrs, SocketAddr, Shutdown};
+use net::{IpAddr, ToSocketAddrs, SocketAddr, Shutdown};
 use sys_common::net2 as net_imp;
 use sys_common::AsInner;
 
@@ -164,6 +164,23 @@ impl TcpListener {
         super::each_addr(addr, net_imp::TcpListener::bind).map(TcpListener)
     }
 
+    /// Creates a new `TcpListener` that listens on all interfaces and
+    /// all available protocols (IPv4 and IPv6) on the specified port.
+    ///
+    /// The returned listener is ready for accepting connections.
+    ///
+    /// Binding with a port number of 0 will request that the OS assigns a port
+    /// to this listener. The port allocated can be queried via the
+    /// `socket_addr` function.
+    ///
+    /// Implementation detail: currently it just binds to `[::]:<port>`
+    /// and accepts IPv6 sockets. However, it is not guaranteed not to
+    /// be changed later. For example, on IPv4-only system it could bind
+    /// on `0.0.0.0:<port>`.
+    pub fn bind_to_port(port: u16) -> io::Result<TcpListener> {
+        TcpListener::bind(&(IpAddr::new_v6(0, 0, 0, 0, 0, 0, 0, 0), port))
+    }
+
     /// Returns the local socket address of this listener.
     pub fn socket_addr(&self) -> io::Result<SocketAddr> {
         self.0.socket_addr()
@@ -215,7 +232,7 @@ mod tests {
     use io::ErrorKind;
     use io::prelude::*;
     use net::*;
-    use net::test::{next_test_ip4, next_test_ip6};
+    use net::test::{next_test_port, next_test_ip4, next_test_ip6};
     use sync::mpsc::channel;
     use thread;
 
@@ -243,6 +260,57 @@ mod tests {
         }
     }
 
+    #[test]
+    fn bind_ipv6_connect_ipv4() {
+        let port = next_test_port();
+
+        let acceptor = t!(TcpListener::bind(&("::", port)));
+
+        let _t = thread::spawn(move || {
+            let mut s = t!(acceptor.accept()).0;
+            t!(s.write(&[10]));
+        });
+
+        let mut buf = [0];
+        let mut c = t!(TcpStream::connect(&("127.0.0.1", port)));
+        t!(c.read(&mut buf));
+        assert!(buf[0] == 10);
+    }
+
+    #[test]
+    fn bind_to_port_connect_ipv4() {
+        let port = next_test_port();
+
+        let acceptor = t!(TcpListener::bind_to_port(port));
+
+        let _t = thread::spawn(move || {
+            let mut s = t!(acceptor.accept()).0;
+            t!(s.write(&[10]));
+        });
+
+        let mut buf = [0];
+        let mut c = t!(TcpStream::connect(&("127.0.0.1", port)));
+        t!(c.read(&mut buf));
+        assert!(buf[0] == 10);
+    }
+
+    #[test]
+    fn bind_to_port_connect_ipv6() {
+        let port = next_test_port();
+
+        let acceptor = t!(TcpListener::bind_to_port(port));
+
+        let _t = thread::spawn(move || {
+            let mut s = t!(acceptor.accept()).0;
+            t!(s.write(&[10]));
+        });
+
+        let mut buf = [0];
+        let mut c = t!(TcpStream::connect(&("::1", port)));
+        t!(c.read(&mut buf));
+        assert!(buf[0] == 10);
+    }
+
     #[test]
     fn connect_error() {
         match TcpStream::connect("0.0.0.0:1") {

src/libstd/net/test.rs

@@ -16,14 +16,16 @@ use sync::atomic::{AtomicUsize, ATOMIC_USIZE_INIT, Ordering};
 
 static PORT: AtomicUsize = ATOMIC_USIZE_INIT;
 
+pub fn next_test_port() -> u16 {
+    PORT.fetch_add(1, Ordering::SeqCst) as u16 + base_port()
+}
+
 pub fn next_test_ip4() -> SocketAddr {
-    SocketAddr::new(IpAddr::new_v4(127, 0, 0, 1),
-                    PORT.fetch_add(1, Ordering::SeqCst) as u16 + base_port())
+    SocketAddr::new(IpAddr::new_v4(127, 0, 0, 1), next_test_port())
 }
 
 pub fn next_test_ip6() -> SocketAddr {
-    SocketAddr::new(IpAddr::new_v6(0, 0, 0, 0, 0, 0, 0, 1),
-                    PORT.fetch_add(1, Ordering::SeqCst) as u16 + base_port())
+    SocketAddr::new(IpAddr::new_v6(0, 0, 0, 0, 0, 0, 0, 1), next_test_port())
 }
 
 // The bots run multiple builds at the same time, and these builds

src/libstd/sys/common/net2.rs

@@ -248,6 +248,16 @@ impl TcpListener {
                             1 as c_int));
         }
 
+        // `IPV6_V6ONLY` is false by default on Linux and OSX, and true
+        // by default on Windows. `TcpListener::bind` should work the
+        // same way on all platforms, so setting this option on Windows.
+        if cfg!(windows) {
+            if let IpAddr::V6(..) = addr.ip() {
+                try!(setsockopt(&sock, libc::IPPROTO_IPV6, libc::IPV6_V6ONLY,
+                                0 as c_int));
+            }
+        }
+
         // Bind our new socket
         let (addrp, len) = addr.into_inner();
         try!(cvt(unsafe { libc::bind(*sock.as_inner(), addrp, len) }));