sgx_tstd/src/net/addr.rs - incubator-teaclave-sgx-sdk - Git at Google

 // Copyright (C) 2017-2018 Baidu, Inc. All Rights Reserved.
 //
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions
 // are met:
 //
 //  * Redistributions of source code must retain the above copyright
 //    notice, this list of conditions and the following disclaimer.
 //  * Redistributions in binary form must reproduce the above copyright
 //    notice, this list of conditions and the following disclaimer in
 //    the documentation and/or other materials provided with the
 //    distribution.
 //  * Neither the name of Baidu, Inc., nor the names of its
 //    contributors may be used to endorse or promote products derived
 //    from this software without specific prior written permission.
 //
 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

 use sgx_trts::libc as c;
 use core::fmt;
 use core::hash;
 use core::mem;
 use core::option;
 use core::iter;
 use alloc::vec;
 use alloc::slice;
 use io;
 use net::{ntoh, hton, IpAddr, Ipv4Addr, Ipv6Addr};
 use sys_common::{FromInner, AsInner, IntoInner};

 /// An internet socket address, either IPv4 or IPv6.
 ///
 /// Internet socket addresses consist of an [IP address], a 16-bit port number, as well
 /// as possibly some version-dependent additional information. See [`SocketAddrV4`]'s and
 /// [`SocketAddrV6`]'s respective documentation for more details.
 ///
 /// The size of a `SocketAddr` instance may vary depending on the target operating
 /// system.
 ///
 #[derive(Copy, Clone, PartialEq, Eq, Hash, Debug)]
 pub enum SocketAddr {
     /// An IPv4 socket address.
     V4(SocketAddrV4),
     /// An IPv6 socket address.
     V6(SocketAddrV6),
 }

 /// An IPv4 socket address.
 ///
 /// IPv4 socket addresses consist of an [IPv4 address] and a 16-bit port number, as
 /// stated in [IETF RFC 793].
 ///
 /// See [`SocketAddr`] for a type encompassing both IPv4 and IPv6 socket addresses.
 ///
 #[derive(Copy)]
 pub struct SocketAddrV4 { inner: c::sockaddr_in }

 /// An IPv6 socket address.
 ///
 /// IPv6 socket addresses consist of an [Ipv6 address], a 16-bit port number, as well
 /// as fields containing the traffic class, the flow label, and a scope identifier
 /// (see [IETF RFC 2553, Section 3.3] for more details).
 ///
 /// See [`SocketAddr`] for a type encompassing both IPv4 and IPv6 socket addresses.
 ///
 /// The size of a `SocketAddrV6` struct may vary depending on the target operating
 /// system.
 ///
 #[derive(Copy)]
 pub struct SocketAddrV6 { inner: c::sockaddr_in6 }

 impl SocketAddr {
     /// Creates a new socket address from an [IP address] and a port number.
     ///
     pub fn new(ip: IpAddr, port: u16) -> SocketAddr {
         match ip {
             IpAddr::V4(a) => SocketAddr::V4(SocketAddrV4::new(a, port)),
             IpAddr::V6(a) => SocketAddr::V6(SocketAddrV6::new(a, port, 0, 0)),
         }
     }

     /// Returns the IP address associated with this socket address.
     ///
     pub fn ip(&self) -> IpAddr {
         match *self {
             SocketAddr::V4(ref a) => IpAddr::V4(*a.ip()),
             SocketAddr::V6(ref a) => IpAddr::V6(*a.ip()),
         }
     }

     /// Changes the IP address associated with this socket address.
     ///
     pub fn set_ip(&mut self, new_ip: IpAddr) {
         // `match (*self, new_ip)` would have us mutate a copy of self only to throw it away.
         match (self, new_ip) {
             (&mut SocketAddr::V4(ref mut a), IpAddr::V4(new_ip)) => a.set_ip(new_ip),
             (&mut SocketAddr::V6(ref mut a), IpAddr::V6(new_ip)) => a.set_ip(new_ip),
             (self_, new_ip) => *self_ = Self::new(new_ip, self_.port()),
         }
     }

     /// Returns the port number associated with this socket address.
     ///
     pub fn port(&self) -> u16 {
         match *self {
             SocketAddr::V4(ref a) => a.port(),
             SocketAddr::V6(ref a) => a.port(),
         }
     }

     /// Changes the port number associated with this socket address.
     ///
     pub fn set_port(&mut self, new_port: u16) {
         match *self {
             SocketAddr::V4(ref mut a) => a.set_port(new_port),
             SocketAddr::V6(ref mut a) => a.set_port(new_port),
         }
     }

     /// Returns [`true`] if the [IP address] in this `SocketAddr` is an
     /// [IPv4 address], and [`false`] otherwise.
     ///
     pub fn is_ipv4(&self) -> bool {
         match *self {
             SocketAddr::V4(_) => true,
             SocketAddr::V6(_) => false,
         }
     }

     /// Returns [`true`] if the [IP address] in this `SocketAddr` is an
     /// [IPv6 address], and [`false`] otherwise.
     ///
     pub fn is_ipv6(&self) -> bool {
         match *self {
             SocketAddr::V4(_) => false,
             SocketAddr::V6(_) => true,
         }
     }
 }

 impl SocketAddrV4 {
     /// Creates a new socket address from an [IPv4 address] and a port number.
     ///
     pub fn new(ip: Ipv4Addr, port: u16) -> SocketAddrV4 {
         SocketAddrV4 {
             inner: c::sockaddr_in {
                 sin_family: c::AF_INET as c::sa_family_t,
                 sin_port: hton(port),
                 sin_addr: *ip.as_inner(),
                 .. unsafe { mem::zeroed() }
             },
         }
     }

     /// Returns the IP address associated with this socket address.
     ///
     pub fn ip(&self) -> &Ipv4Addr {
         unsafe {
             &*(&self.inner.sin_addr as *const c::in_addr as *const Ipv4Addr)
         }
     }

     /// Changes the IP address associated with this socket address.
     ///
     pub fn set_ip(&mut self, new_ip: Ipv4Addr) {
         self.inner.sin_addr = *new_ip.as_inner()
     }

     /// Returns the port number associated with this socket address.
     ///
     pub fn port(&self) -> u16 {
         ntoh(self.inner.sin_port)
     }

     /// Changes the port number associated with this socket address.
     ///
     pub fn set_port(&mut self, new_port: u16) {
         self.inner.sin_port = hton(new_port);
     }
 }

 impl SocketAddrV6 {
     /// Creates a new socket address from an [IPv6 address], a 16-bit port number,
     /// and the `flowinfo` and `scope_id` fields.
     ///
     /// For more information on the meaning and layout of the `flowinfo` and `scope_id`
     /// parameters, see [IETF RFC 2553, Section 3.3].
     ///
     pub fn new(ip: Ipv6Addr, port: u16, flowinfo: u32, scope_id: u32)
                -> SocketAddrV6 {
         SocketAddrV6 {
             inner: c::sockaddr_in6 {
                 sin6_family: c::AF_INET6 as c::sa_family_t,
                 sin6_port: hton(port),
                 sin6_addr: *ip.as_inner(),
                 sin6_flowinfo: flowinfo,
                 sin6_scope_id: scope_id,
                 .. unsafe { mem::zeroed() }
             },
         }
     }

     /// Returns the IP address associated with this socket address.
     ///
     pub fn ip(&self) -> &Ipv6Addr {
         unsafe {
             &*(&self.inner.sin6_addr as *const c::in6_addr as *const Ipv6Addr)
         }
     }

     /// Changes the IP address associated with this socket address.
     ///
     pub fn set_ip(&mut self, new_ip: Ipv6Addr) {
         self.inner.sin6_addr = *new_ip.as_inner()
     }

     /// Returns the port number associated with this socket address.
     ///
     pub fn port(&self) -> u16 {
         ntoh(self.inner.sin6_port)
     }

     /// Changes the port number associated with this socket address.
     ///
     pub fn set_port(&mut self, new_port: u16) {
         self.inner.sin6_port = hton(new_port);
     }

     /// Returns the flow information associated with this address.
     ///
     /// This information corresponds to the `sin6_flowinfo` field in C's `netinet/in.h`,
     /// as specified in [IETF RFC 2553, Section 3.3].
     /// It combines information about the flow label and the traffic class as specified
     /// in [IETF RFC 2460], respectively [Section 6] and [Section 7].
     ///
     pub fn flowinfo(&self) -> u32 {
         self.inner.sin6_flowinfo
     }

     /// Changes the flow information associated with this socket address.
     ///
     /// See the [`flowinfo`] method's documentation for more details.
     ///
     /// [`flowinfo`]: #method.flowinfo
     ///
     pub fn set_flowinfo(&mut self, new_flowinfo: u32) {
         self.inner.sin6_flowinfo = new_flowinfo;
     }

     /// Returns the scope ID associated with this address.
     ///
     /// This information corresponds to the `sin6_scope_id` field in C's `netinet/in.h`,
     /// as specified in [IETF RFC 2553, Section 3.3].
     ///
     pub fn scope_id(&self) -> u32 {
         self.inner.sin6_scope_id
     }

     /// Change the scope ID associated with this socket address.
     ///
     /// See the [`scope_id`] method's documentation for more details.
     ///
     /// [`scope_id`]: #method.scope_id
     ///
     pub fn set_scope_id(&mut self, new_scope_id: u32) {
         self.inner.sin6_scope_id = new_scope_id;
     }
 }

 impl FromInner<c::sockaddr_in> for SocketAddrV4 {
     fn from_inner(addr: c::sockaddr_in) -> SocketAddrV4 {
         SocketAddrV4 { inner: addr }
     }
 }

 impl FromInner<c::sockaddr_in6> for SocketAddrV6 {
     fn from_inner(addr: c::sockaddr_in6) -> SocketAddrV6 {
         SocketAddrV6 { inner: addr }
     }
 }

 impl From<SocketAddrV4> for SocketAddr {
     fn from(sock4: SocketAddrV4) -> SocketAddr {
         SocketAddr::V4(sock4)
     }
 }

 impl From<SocketAddrV6> for SocketAddr {
     fn from(sock6: SocketAddrV6) -> SocketAddr {
         SocketAddr::V6(sock6)
     }
 }

 impl<I: Into<IpAddr>> From<(I, u16)> for SocketAddr {
     fn from(pieces: (I, u16)) -> SocketAddr {
         SocketAddr::new(pieces.0.into(), pieces.1)
     }
 }

 impl<'a> IntoInner<(*const c::sockaddr, c::socklen_t)> for &'a SocketAddr {
     fn into_inner(self) -> (*const c::sockaddr, c::socklen_t) {
         match *self {
             SocketAddr::V4(ref a) => {
                 (a as *const _ as *const _, mem::size_of_val(a) as c::socklen_t)
             }
             SocketAddr::V6(ref a) => {
                 (a as *const _ as *const _, mem::size_of_val(a) as c::socklen_t)
             }
         }
     }
 }

 impl fmt::Display for SocketAddr {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         match *self {
             SocketAddr::V4(ref a) => a.fmt(f),
             SocketAddr::V6(ref a) => a.fmt(f),
         }
     }
 }

 impl fmt::Display for SocketAddrV4 {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         write!(f, "{}:{}", self.ip(), self.port())
     }
 }

 impl fmt::Debug for SocketAddrV4 {
     fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
         fmt::Display::fmt(self, fmt)
     }
 }

 impl fmt::Display for SocketAddrV6 {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         write!(f, "[{}]:{}", self.ip(), self.port())
     }
 }

 impl fmt::Debug for SocketAddrV6 {
     fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
         fmt::Display::fmt(self, fmt)
     }
 }

 impl Clone for SocketAddrV4 {
     fn clone(&self) -> SocketAddrV4 { *self }
 }

 impl Clone for SocketAddrV6 {
     fn clone(&self) -> SocketAddrV6 { *self }
 }

 impl PartialEq for SocketAddrV4 {
     fn eq(&self, other: &SocketAddrV4) -> bool {
         self.inner.sin_port == other.inner.sin_port &&
             self.inner.sin_addr.s_addr == other.inner.sin_addr.s_addr
     }
 }

 impl PartialEq for SocketAddrV6 {
     fn eq(&self, other: &SocketAddrV6) -> bool {
         self.inner.sin6_port == other.inner.sin6_port &&
             self.inner.sin6_addr.s6_addr == other.inner.sin6_addr.s6_addr &&
             self.inner.sin6_flowinfo == other.inner.sin6_flowinfo &&
             self.inner.sin6_scope_id == other.inner.sin6_scope_id
     }
 }

 impl Eq for SocketAddrV4 {}

 impl Eq for SocketAddrV6 {}

 impl hash::Hash for SocketAddrV4 {
     fn hash<H: hash::Hasher>(&self, s: &mut H) {
         (self.inner.sin_port, self.inner.sin_addr.s_addr).hash(s)
     }
 }

 impl hash::Hash for SocketAddrV6 {
     fn hash<H: hash::Hasher>(&self, s: &mut H) {
         (self.inner.sin6_port, &self.inner.sin6_addr.s6_addr,
          self.inner.sin6_flowinfo, self.inner.sin6_scope_id).hash(s)
     }
 }

 /// A trait for objects which can be converted or resolved to one or more
 /// [`SocketAddr`] values.
 ///
 /// This trait is used for generic address resolution when constructing network
 /// objects.  By default it is implemented for the following types:
 ///
 ///  * [`SocketAddr`]: [`to_socket_addrs`] is the identity function.
 ///
 ///  * [`SocketAddrV4`], [`SocketAddrV6`], `(`[`IpAddr`]`, `[`u16`]`)`,
 ///    `(`[`Ipv4Addr`]`, `[`u16`]`)`, `(`[`Ipv6Addr`]`, `[`u16`]`)`:
 ///    [`to_socket_addrs`] constructs a [`SocketAddr`] trivially.
 ///
 ///  * `(`[`&str`]`, `[`u16`]`)`: the string should be either a string representation
 ///    of an [`IpAddr`] address as expected by [`FromStr`] implementation or a host
 ///    name.
 ///
 ///  * [`&str`]: the string should be either a string representation of a
 ///    [`SocketAddr`] as expected by its [`FromStr`] implementation or a string like
 ///    `<host_name>:<port>` pair where `<port>` is a [`u16`] value.
 ///
 /// This trait allows constructing network objects like [`TcpStream`] or
 /// [`UdpSocket`] easily with values of various types for the bind/connection
 /// address. It is needed because sometimes one type is more appropriate than
 /// the other: for simple uses a string like `"localhost:12345"` is much nicer
 /// than manual construction of the corresponding [`SocketAddr`], but sometimes
 /// [`SocketAddr`] value is *the* main source of the address, and converting it to
 /// some other type (e.g. a string) just for it to be converted back to
 /// [`SocketAddr`] in constructor methods is pointless.
 ///
 /// Addresses returned by the operating system that are not IP addresses are
 /// silently ignored.
 ///
 pub trait ToSocketAddrs {
     /// Returned iterator over socket addresses which this type may correspond
     /// to.
     type Iter: Iterator<Item=SocketAddr>;

     /// Converts this object to an iterator of resolved `SocketAddr`s.
     ///
     /// The returned iterator may not actually yield any values depending on the
     /// outcome of any resolution performed.
     ///
     /// Note that this function may block the current thread while resolution is
     /// performed.
     fn to_socket_addrs(&self) -> io::Result<Self::Iter>;
 }

 impl ToSocketAddrs for SocketAddr {
     type Iter = option::IntoIter<SocketAddr>;
     fn to_socket_addrs(&self) -> io::Result<option::IntoIter<SocketAddr>> {
         Ok(Some(*self).into_iter())
     }
 }

 impl ToSocketAddrs for SocketAddrV4 {
     type Iter = option::IntoIter<SocketAddr>;
     fn to_socket_addrs(&self) -> io::Result<option::IntoIter<SocketAddr>> {
         SocketAddr::V4(*self).to_socket_addrs()
     }
 }

 impl ToSocketAddrs for SocketAddrV6 {
     type Iter = option::IntoIter<SocketAddr>;
     fn to_socket_addrs(&self) -> io::Result<option::IntoIter<SocketAddr>> {
         SocketAddr::V6(*self).to_socket_addrs()
     }
 }

 impl ToSocketAddrs for (IpAddr, u16) {
     type Iter = option::IntoIter<SocketAddr>;
     fn to_socket_addrs(&self) -> io::Result<option::IntoIter<SocketAddr>> {
         let (ip, port) = *self;
         match ip {
             IpAddr::V4(ref a) => (*a, port).to_socket_addrs(),
             IpAddr::V6(ref a) => (*a, port).to_socket_addrs(),
         }
     }
 }

 impl ToSocketAddrs for (Ipv4Addr, u16) {
     type Iter = option::IntoIter<SocketAddr>;
     fn to_socket_addrs(&self) -> io::Result<option::IntoIter<SocketAddr>> {
         let (ip, port) = *self;
         SocketAddrV4::new(ip, port).to_socket_addrs()
     }
 }

 impl ToSocketAddrs for (Ipv6Addr, u16) {
     type Iter = option::IntoIter<SocketAddr>;
     fn to_socket_addrs(&self) -> io::Result<option::IntoIter<SocketAddr>> {
         let (ip, port) = *self;
         SocketAddrV6::new(ip, port, 0, 0).to_socket_addrs()
     }
 }

 impl<'a> ToSocketAddrs for (&'a str, u16) {
     type Iter = vec::IntoIter<SocketAddr>;
     fn to_socket_addrs(&self) -> io::Result<vec::IntoIter<SocketAddr>> {
         let (host, port) = *self;

         // try to parse the host as a regular IP address first
         if let Ok(addr) = host.parse::<Ipv4Addr>() {
             let addr = SocketAddrV4::new(addr, port);
             return Ok(vec![SocketAddr::V4(addr)].into_iter())
         }
         if let Ok(addr) = host.parse::<Ipv6Addr>() {
             let addr = SocketAddrV6::new(addr, port, 0, 0);
             return Ok(vec![SocketAddr::V6(addr)].into_iter())
         }

         Err(io::Error::new(io::ErrorKind::InvalidInput, "invalid socket address"))
         //resolve_socket_addr(host, port)
     }
 }

 // accepts strings like 'localhost:12345'
 #[allow(unused_variables)]
 impl ToSocketAddrs for str {
     type Iter = vec::IntoIter<SocketAddr>;
     fn to_socket_addrs(&self) -> io::Result<vec::IntoIter<SocketAddr>> {
         // try to parse as a regular SocketAddr first
         if let Some(addr) = self.parse().ok() {
             return Ok(vec![addr].into_iter());
         }

         macro_rules! try_opt {
             ($e:expr, $msg:expr) => (
                 match $e {
                     Some(r) => r,
                     None => return Err(io::Error::new(io::ErrorKind::InvalidInput,
                                                       $msg)),
                 }
             )
         }

         // split the string by ':' and convert the second part to u16
         let mut parts_iter = self.rsplitn(2, ':');
         let port_str = try_opt!(parts_iter.next(), "invalid socket address");
         let host = try_opt!(parts_iter.next(), "invalid socket address");
         let port: u16 = try_opt!(port_str.parse().ok(), "invalid port value");
         Err(io::Error::new(io::ErrorKind::InvalidInput, "invalid socket address"))
         //resolve_socket_addr(host, port)
     }
 }

 impl<'a> ToSocketAddrs for &'a [SocketAddr] {
     type Iter = iter::Cloned<slice::Iter<'a, SocketAddr>>;

     fn to_socket_addrs(&self) -> io::Result<Self::Iter> {
         Ok(self.iter().cloned())
     }
 }

 impl<'a, T: ToSocketAddrs + ?Sized> ToSocketAddrs for &'a T {
     type Iter = T::Iter;
     fn to_socket_addrs(&self) -> io::Result<T::Iter> {
         (**self).to_socket_addrs()
     }
 }

 impl ToSocketAddrs for String {
     type Iter = vec::IntoIter<SocketAddr>;
     fn to_socket_addrs(&self) -> io::Result<vec::IntoIter<SocketAddr>> {
         (&**self).to_socket_addrs()
     }
 }
	// Copyright (C) 2017-2018 Baidu, Inc. All Rights Reserved.
	//
	// Redistribution and use in source and binary forms, with or without
	// modification, are permitted provided that the following conditions
	// are met:
	//
	// * Redistributions of source code must retain the above copyright
	// notice, this list of conditions and the following disclaimer.
	// * Redistributions in binary form must reproduce the above copyright
	// notice, this list of conditions and the following disclaimer in
	// the documentation and/or other materials provided with the
	// distribution.
	// * Neither the name of Baidu, Inc., nor the names of its
	// contributors may be used to endorse or promote products derived
	// from this software without specific prior written permission.
	//
	// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
	// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
	// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
	// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
	// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
	// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
	// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
	// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
	// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
	// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
	// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

	use sgx_trts::libc as c;
	use core::fmt;
	use core::hash;
	use core::mem;
	use core::option;
	use core::iter;
	use alloc::vec;
	use alloc::slice;
	use io;
	use net::{ntoh, hton, IpAddr, Ipv4Addr, Ipv6Addr};
	use sys_common::{FromInner, AsInner, IntoInner};

	/// An internet socket address, either IPv4 or IPv6.
	///
	/// Internet socket addresses consist of an [IP address], a 16-bit port number, as well
	/// as possibly some version-dependent additional information. See [`SocketAddrV4`]'s and
	/// [`SocketAddrV6`]'s respective documentation for more details.
	///
	/// The size of a `SocketAddr` instance may vary depending on the target operating
	/// system.
	///
	#[derive(Copy, Clone, PartialEq, Eq, Hash, Debug)]
	pub enum SocketAddr {
	/// An IPv4 socket address.
	V4(SocketAddrV4),
	/// An IPv6 socket address.
	V6(SocketAddrV6),
	}

	/// An IPv4 socket address.
	///
	/// IPv4 socket addresses consist of an [IPv4 address] and a 16-bit port number, as
	/// stated in [IETF RFC 793].
	///
	/// See [`SocketAddr`] for a type encompassing both IPv4 and IPv6 socket addresses.
	///
	#[derive(Copy)]
	pub struct SocketAddrV4 { inner: c::sockaddr_in }

	/// An IPv6 socket address.
	///
	/// IPv6 socket addresses consist of an [Ipv6 address], a 16-bit port number, as well
	/// as fields containing the traffic class, the flow label, and a scope identifier
	/// (see [IETF RFC 2553, Section 3.3] for more details).
	///
	/// See [`SocketAddr`] for a type encompassing both IPv4 and IPv6 socket addresses.
	///
	/// The size of a `SocketAddrV6` struct may vary depending on the target operating
	/// system.
	///
	#[derive(Copy)]
	pub struct SocketAddrV6 { inner: c::sockaddr_in6 }

	impl SocketAddr {
	/// Creates a new socket address from an [IP address] and a port number.
	///
	pub fn new(ip: IpAddr, port: u16) -> SocketAddr {
	match ip {
	IpAddr::V4(a) => SocketAddr::V4(SocketAddrV4::new(a, port)),
	IpAddr::V6(a) => SocketAddr::V6(SocketAddrV6::new(a, port, 0, 0)),
	}
	}

	/// Returns the IP address associated with this socket address.
	///
	pub fn ip(&self) -> IpAddr {
	match *self {
	SocketAddr::V4(ref a) => IpAddr::V4(*a.ip()),
	SocketAddr::V6(ref a) => IpAddr::V6(*a.ip()),
	}
	}

	/// Changes the IP address associated with this socket address.
	///
	pub fn set_ip(&mut self, new_ip: IpAddr) {
	// `match (*self, new_ip)` would have us mutate a copy of self only to throw it away.
	match (self, new_ip) {
	(&mut SocketAddr::V4(ref mut a), IpAddr::V4(new_ip)) => a.set_ip(new_ip),
	(&mut SocketAddr::V6(ref mut a), IpAddr::V6(new_ip)) => a.set_ip(new_ip),
	(self_, new_ip) => *self_ = Self::new(new_ip, self_.port()),
	}
	}

	/// Returns the port number associated with this socket address.
	///
	pub fn port(&self) -> u16 {
	match *self {
	SocketAddr::V4(ref a) => a.port(),
	SocketAddr::V6(ref a) => a.port(),
	}
	}

	/// Changes the port number associated with this socket address.
	///
	pub fn set_port(&mut self, new_port: u16) {
	match *self {
	SocketAddr::V4(ref mut a) => a.set_port(new_port),
	SocketAddr::V6(ref mut a) => a.set_port(new_port),
	}
	}

	/// Returns [`true`] if the [IP address] in this `SocketAddr` is an
	/// [IPv4 address], and [`false`] otherwise.
	///
	pub fn is_ipv4(&self) -> bool {
	match *self {
	SocketAddr::V4(_) => true,
	SocketAddr::V6(_) => false,
	}
	}

	/// Returns [`true`] if the [IP address] in this `SocketAddr` is an
	/// [IPv6 address], and [`false`] otherwise.
	///
	pub fn is_ipv6(&self) -> bool {
	match *self {
	SocketAddr::V4(_) => false,
	SocketAddr::V6(_) => true,
	}
	}
	}

	impl SocketAddrV4 {
	/// Creates a new socket address from an [IPv4 address] and a port number.
	///
	pub fn new(ip: Ipv4Addr, port: u16) -> SocketAddrV4 {
	SocketAddrV4 {
	inner: c::sockaddr_in {
	sin_family: c::AF_INET as c::sa_family_t,
	sin_port: hton(port),
	sin_addr: *ip.as_inner(),
	.. unsafe { mem::zeroed() }
	},
	}
	}

	/// Returns the IP address associated with this socket address.
	///
	pub fn ip(&self) -> &Ipv4Addr {
	unsafe {
	&(&self.inner.sin_addr as const c::in_addr as *const Ipv4Addr)
	}
	}

	/// Changes the IP address associated with this socket address.
	///
	pub fn set_ip(&mut self, new_ip: Ipv4Addr) {
	self.inner.sin_addr = *new_ip.as_inner()
	}

	/// Returns the port number associated with this socket address.
	///
	pub fn port(&self) -> u16 {
	ntoh(self.inner.sin_port)
	}

	/// Changes the port number associated with this socket address.
	///
	pub fn set_port(&mut self, new_port: u16) {
	self.inner.sin_port = hton(new_port);
	}
	}

	impl SocketAddrV6 {
	/// Creates a new socket address from an [IPv6 address], a 16-bit port number,
	/// and the `flowinfo` and `scope_id` fields.
	///
	/// For more information on the meaning and layout of the `flowinfo` and `scope_id`
	/// parameters, see [IETF RFC 2553, Section 3.3].
	///
	pub fn new(ip: Ipv6Addr, port: u16, flowinfo: u32, scope_id: u32)
	-> SocketAddrV6 {
	SocketAddrV6 {
	inner: c::sockaddr_in6 {
	sin6_family: c::AF_INET6 as c::sa_family_t,
	sin6_port: hton(port),
	sin6_addr: *ip.as_inner(),
	sin6_flowinfo: flowinfo,
	sin6_scope_id: scope_id,
	.. unsafe { mem::zeroed() }
	},
	}
	}

	/// Returns the IP address associated with this socket address.
	///
	pub fn ip(&self) -> &Ipv6Addr {
	unsafe {
	&(&self.inner.sin6_addr as const c::in6_addr as *const Ipv6Addr)
	}
	}

	/// Changes the IP address associated with this socket address.
	///
	pub fn set_ip(&mut self, new_ip: Ipv6Addr) {
	self.inner.sin6_addr = *new_ip.as_inner()
	}

	/// Returns the port number associated with this socket address.
	///
	pub fn port(&self) -> u16 {
	ntoh(self.inner.sin6_port)
	}

	/// Changes the port number associated with this socket address.
	///
	pub fn set_port(&mut self, new_port: u16) {
	self.inner.sin6_port = hton(new_port);
	}

	/// Returns the flow information associated with this address.
	///
	/// This information corresponds to the `sin6_flowinfo` field in C's `netinet/in.h`,
	/// as specified in [IETF RFC 2553, Section 3.3].
	/// It combines information about the flow label and the traffic class as specified
	/// in [IETF RFC 2460], respectively [Section 6] and [Section 7].
	///
	pub fn flowinfo(&self) -> u32 {
	self.inner.sin6_flowinfo
	}

	/// Changes the flow information associated with this socket address.
	///
	/// See the [`flowinfo`] method's documentation for more details.
	///
	/// [`flowinfo`]: #method.flowinfo
	///
	pub fn set_flowinfo(&mut self, new_flowinfo: u32) {
	self.inner.sin6_flowinfo = new_flowinfo;
	}

	/// Returns the scope ID associated with this address.
	///
	/// This information corresponds to the `sin6_scope_id` field in C's `netinet/in.h`,
	/// as specified in [IETF RFC 2553, Section 3.3].
	///
	pub fn scope_id(&self) -> u32 {
	self.inner.sin6_scope_id
	}

	/// Change the scope ID associated with this socket address.
	///
	/// See the [`scope_id`] method's documentation for more details.
	///
	/// [`scope_id`]: #method.scope_id
	///
	pub fn set_scope_id(&mut self, new_scope_id: u32) {
	self.inner.sin6_scope_id = new_scope_id;
	}
	}

	impl FromInner<c::sockaddr_in> for SocketAddrV4 {
	fn from_inner(addr: c::sockaddr_in) -> SocketAddrV4 {
	SocketAddrV4 { inner: addr }
	}
	}

	impl FromInner<c::sockaddr_in6> for SocketAddrV6 {
	fn from_inner(addr: c::sockaddr_in6) -> SocketAddrV6 {
	SocketAddrV6 { inner: addr }
	}
	}

	impl From<SocketAddrV4> for SocketAddr {
	fn from(sock4: SocketAddrV4) -> SocketAddr {
	SocketAddr::V4(sock4)
	}
	}

	impl From<SocketAddrV6> for SocketAddr {
	fn from(sock6: SocketAddrV6) -> SocketAddr {
	SocketAddr::V6(sock6)
	}
	}

	impl<I: Into<IpAddr>> From<(I, u16)> for SocketAddr {
	fn from(pieces: (I, u16)) -> SocketAddr {
	SocketAddr::new(pieces.0.into(), pieces.1)
	}
	}

	impl<'a> IntoInner<(*const c::sockaddr, c::socklen_t)> for &'a SocketAddr {
	fn into_inner(self) -> (*const c::sockaddr, c::socklen_t) {
	match *self {
	SocketAddr::V4(ref a) => {
	(a as const _ as const _, mem::size_of_val(a) as c::socklen_t)
	}
	SocketAddr::V6(ref a) => {
	(a as const _ as const _, mem::size_of_val(a) as c::socklen_t)
	}
	}
	}
	}

	impl fmt::Display for SocketAddr {
	fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
	match *self {
	SocketAddr::V4(ref a) => a.fmt(f),
	SocketAddr::V6(ref a) => a.fmt(f),
	}
	}
	}

	impl fmt::Display for SocketAddrV4 {
	fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
	write!(f, "{}:{}", self.ip(), self.port())
	}
	}

	impl fmt::Debug for SocketAddrV4 {
	fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
	fmt::Display::fmt(self, fmt)
	}
	}

	impl fmt::Display for SocketAddrV6 {
	fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
	write!(f, "[{}]:{}", self.ip(), self.port())
	}
	}

	impl fmt::Debug for SocketAddrV6 {
	fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
	fmt::Display::fmt(self, fmt)
	}
	}

	impl Clone for SocketAddrV4 {
	fn clone(&self) -> SocketAddrV4 { *self }
	}

	impl Clone for SocketAddrV6 {
	fn clone(&self) -> SocketAddrV6 { *self }
	}

	impl PartialEq for SocketAddrV4 {
	fn eq(&self, other: &SocketAddrV4) -> bool {
	self.inner.sin_port == other.inner.sin_port &&
	self.inner.sin_addr.s_addr == other.inner.sin_addr.s_addr
	}
	}

	impl PartialEq for SocketAddrV6 {
	fn eq(&self, other: &SocketAddrV6) -> bool {
	self.inner.sin6_port == other.inner.sin6_port &&
	self.inner.sin6_addr.s6_addr == other.inner.sin6_addr.s6_addr &&
	self.inner.sin6_flowinfo == other.inner.sin6_flowinfo &&
	self.inner.sin6_scope_id == other.inner.sin6_scope_id
	}
	}

	impl Eq for SocketAddrV4 {}

	impl Eq for SocketAddrV6 {}

	impl hash::Hash for SocketAddrV4 {
	fn hash<H: hash::Hasher>(&self, s: &mut H) {
	(self.inner.sin_port, self.inner.sin_addr.s_addr).hash(s)
	}
	}

	impl hash::Hash for SocketAddrV6 {
	fn hash<H: hash::Hasher>(&self, s: &mut H) {
	(self.inner.sin6_port, &self.inner.sin6_addr.s6_addr,
	self.inner.sin6_flowinfo, self.inner.sin6_scope_id).hash(s)
	}
	}

	/// A trait for objects which can be converted or resolved to one or more
	/// [`SocketAddr`] values.
	///
	/// This trait is used for generic address resolution when constructing network
	/// objects. By default it is implemented for the following types:
	///
	/// * [`SocketAddr`]: [`to_socket_addrs`] is the identity function.
	///
	/// * [`SocketAddrV4`], [`SocketAddrV6`], `(`[`IpAddr`]`, `[`u16`]`)`,
	/// `(`[`Ipv4Addr`]`, `[`u16`]`)`, `(`[`Ipv6Addr`]`, `[`u16`]`)`:
	/// [`to_socket_addrs`] constructs a [`SocketAddr`] trivially.
	///
	/// * `(`[`&str`]`, `[`u16`]`)`: the string should be either a string representation
	/// of an [`IpAddr`] address as expected by [`FromStr`] implementation or a host
	/// name.
	///
	/// * [`&str`]: the string should be either a string representation of a
	/// [`SocketAddr`] as expected by its [`FromStr`] implementation or a string like
	/// `<host_name>:<port>` pair where `<port>` is a [`u16`] value.
	///
	/// This trait allows constructing network objects like [`TcpStream`] or
	/// [`UdpSocket`] easily with values of various types for the bind/connection
	/// address. It is needed because sometimes one type is more appropriate than
	/// the other: for simple uses a string like `"localhost:12345"` is much nicer
	/// than manual construction of the corresponding [`SocketAddr`], but sometimes
	/// [`SocketAddr`] value is the main source of the address, and converting it to
	/// some other type (e.g. a string) just for it to be converted back to
	/// [`SocketAddr`] in constructor methods is pointless.
	///
	/// Addresses returned by the operating system that are not IP addresses are
	/// silently ignored.
	///
	pub trait ToSocketAddrs {
	/// Returned iterator over socket addresses which this type may correspond
	/// to.
	type Iter: Iterator<Item=SocketAddr>;

	/// Converts this object to an iterator of resolved `SocketAddr`s.
	///
	/// The returned iterator may not actually yield any values depending on the
	/// outcome of any resolution performed.
	///
	/// Note that this function may block the current thread while resolution is
	/// performed.
	fn to_socket_addrs(&self) -> io::Result<Self::Iter>;
	}

	impl ToSocketAddrs for SocketAddr {
	type Iter = option::IntoIter<SocketAddr>;
	fn to_socket_addrs(&self) -> io::Result<option::IntoIter<SocketAddr>> {
	Ok(Some(*self).into_iter())
	}
	}

	impl ToSocketAddrs for SocketAddrV4 {
	type Iter = option::IntoIter<SocketAddr>;
	fn to_socket_addrs(&self) -> io::Result<option::IntoIter<SocketAddr>> {
	SocketAddr::V4(*self).to_socket_addrs()
	}
	}

	impl ToSocketAddrs for SocketAddrV6 {
	type Iter = option::IntoIter<SocketAddr>;
	fn to_socket_addrs(&self) -> io::Result<option::IntoIter<SocketAddr>> {
	SocketAddr::V6(*self).to_socket_addrs()
	}
	}

	impl ToSocketAddrs for (IpAddr, u16) {
	type Iter = option::IntoIter<SocketAddr>;
	fn to_socket_addrs(&self) -> io::Result<option::IntoIter<SocketAddr>> {
	let (ip, port) = *self;
	match ip {
	IpAddr::V4(ref a) => (*a, port).to_socket_addrs(),
	IpAddr::V6(ref a) => (*a, port).to_socket_addrs(),
	}
	}
	}

	impl ToSocketAddrs for (Ipv4Addr, u16) {
	type Iter = option::IntoIter<SocketAddr>;
	fn to_socket_addrs(&self) -> io::Result<option::IntoIter<SocketAddr>> {
	let (ip, port) = *self;
	SocketAddrV4::new(ip, port).to_socket_addrs()
	}
	}

	impl ToSocketAddrs for (Ipv6Addr, u16) {
	type Iter = option::IntoIter<SocketAddr>;
	fn to_socket_addrs(&self) -> io::Result<option::IntoIter<SocketAddr>> {
	let (ip, port) = *self;
	SocketAddrV6::new(ip, port, 0, 0).to_socket_addrs()
	}
	}

	impl<'a> ToSocketAddrs for (&'a str, u16) {
	type Iter = vec::IntoIter<SocketAddr>;
	fn to_socket_addrs(&self) -> io::Result<vec::IntoIter<SocketAddr>> {
	let (host, port) = *self;

	// try to parse the host as a regular IP address first
	if let Ok(addr) = host.parse::<Ipv4Addr>() {
	let addr = SocketAddrV4::new(addr, port);
	return Ok(vec![SocketAddr::V4(addr)].into_iter())
	}
	if let Ok(addr) = host.parse::<Ipv6Addr>() {
	let addr = SocketAddrV6::new(addr, port, 0, 0);
	return Ok(vec![SocketAddr::V6(addr)].into_iter())
	}

	Err(io::Error::new(io::ErrorKind::InvalidInput, "invalid socket address"))
	//resolve_socket_addr(host, port)
	}
	}

	// accepts strings like 'localhost:12345'
	#[allow(unused_variables)]
	impl ToSocketAddrs for str {
	type Iter = vec::IntoIter<SocketAddr>;
	fn to_socket_addrs(&self) -> io::Result<vec::IntoIter<SocketAddr>> {
	// try to parse as a regular SocketAddr first
	if let Some(addr) = self.parse().ok() {
	return Ok(vec![addr].into_iter());
	}

	macro_rules! try_opt {
	($e:expr, $msg:expr) => (
	match $e {
	Some(r) => r,
	None => return Err(io::Error::new(io::ErrorKind::InvalidInput,
	$msg)),
	}
	)
	}

	// split the string by ':' and convert the second part to u16
	let mut parts_iter = self.rsplitn(2, ':');
	let port_str = try_opt!(parts_iter.next(), "invalid socket address");
	let host = try_opt!(parts_iter.next(), "invalid socket address");
	let port: u16 = try_opt!(port_str.parse().ok(), "invalid port value");
	Err(io::Error::new(io::ErrorKind::InvalidInput, "invalid socket address"))
	//resolve_socket_addr(host, port)
	}
	}

	impl<'a> ToSocketAddrs for &'a [SocketAddr] {
	type Iter = iter::Cloned<slice::Iter<'a, SocketAddr>>;

	fn to_socket_addrs(&self) -> io::Result<Self::Iter> {
	Ok(self.iter().cloned())
	}
	}

	impl<'a, T: ToSocketAddrs + ?Sized> ToSocketAddrs for &'a T {
	type Iter = T::Iter;
	fn to_socket_addrs(&self) -> io::Result<T::Iter> {
	(**self).to_socket_addrs()
	}
	}

	impl ToSocketAddrs for String {
	type Iter = vec::IntoIter<SocketAddr>;
	fn to_socket_addrs(&self) -> io::Result<vec::IntoIter<SocketAddr>> {
	(&**self).to_socket_addrs()
	}
	}