path: root/src/sys/socket/addr.rs

use super::sa_family_t;
use {Error, Result, NixPath};
use errno::Errno;
use libc;
use std::{fmt, hash, mem, net, ptr, slice};
use std::ffi::OsStr;
use std::path::Path;
use std::os::unix::ffi::OsStrExt;
#[cfg(any(target_os = "android", target_os = "linux"))]
use ::sys::socket::addr::netlink::NetlinkAddr;
#[cfg(any(target_os = "ios", target_os = "macos"))]
use std::os::unix::io::RawFd;
#[cfg(any(target_os = "ios", target_os = "macos"))]
use ::sys::socket::addr::sys_control::SysControlAddr;

/// These constants specify the protocol family to be used
/// in [`socket`](fn.socket.html) and [`socketpair`](fn.socketpair.html)
#[repr(i32)]
#[derive(Copy, Clone, PartialEq, Eq, Debug, Hash)]
pub enum AddressFamily {
    /// Local communication (see [`unix(7)`](http://man7.org/linux/man-pages/man7/unix.7.html))
    Unix = libc::AF_UNIX,
    /// IPv4 Internet protocols (see [`ip(7)`](http://man7.org/linux/man-pages/man7/ip.7.html))
    Inet = libc::AF_INET,
    /// IPv6 Internet protocols (see [`ipv6(7)`](http://man7.org/linux/man-pages/man7/ipv6.7.html))
    Inet6 = libc::AF_INET6,
    /// Kernel user interface device (see [`netlink(7)`](http://man7.org/linux/man-pages/man7/netlink.7.html))
    #[cfg(any(target_os = "android", target_os = "linux"))]
    Netlink = libc::AF_NETLINK,
    /// Low level packet interface (see [`packet(7)`](http://man7.org/linux/man-pages/man7/packet.7.html))
    #[cfg(any(target_os = "android", target_os = "linux"))]
    Packet = libc::AF_PACKET,
    /// KEXT Controls and Notifications
    #[cfg(any(target_os = "ios", target_os = "macos"))]
    System = libc::AF_SYSTEM,
    /// Amateur radio AX.25 protocol
    #[cfg(any(target_os = "android", target_os = "linux"))]
    Ax25 = libc::AF_AX25,
    /// IPX - Novell protocols
    Ipx = libc::AF_IPX,
    /// AppleTalk
    AppleTalk = libc::AF_APPLETALK,
    #[cfg(any(target_os = "android", target_os = "linux"))]
    NetRom = libc::AF_NETROM,
    #[cfg(any(target_os = "android", target_os = "linux"))]
    Bridge = libc::AF_BRIDGE,
    /// Access to raw ATM PVCs
    #[cfg(any(target_os = "android", target_os = "linux"))]
    AtmPvc = libc::AF_ATMPVC,
    /// ITU-T X.25 / ISO-8208 protocol (see [`x25(7)`](http://man7.org/linux/man-pages/man7/x25.7.html))
    #[cfg(any(target_os = "android", target_os = "linux"))]
    X25 = libc::AF_X25,
    #[cfg(any(target_os = "android", target_os = "linux"))]
    Rose = libc::AF_ROSE,
    Decnet = libc::AF_DECnet,
    #[cfg(any(target_os = "android", target_os = "linux"))]
    NetBeui = libc::AF_NETBEUI,
    #[cfg(any(target_os = "android", target_os = "linux"))]
    Security = libc::AF_SECURITY,
    #[cfg(any(target_os = "android", target_os = "linux"))]
    Key = libc::AF_KEY,
    #[cfg(any(target_os = "android", target_os = "linux"))]
    Ash = libc::AF_ASH,
    #[cfg(any(target_os = "android", target_os = "linux"))]
    Econet = libc::AF_ECONET,
    #[cfg(any(target_os = "android", target_os = "linux"))]
    AtmSvc = libc::AF_ATMSVC,
    #[cfg(any(target_os = "android", target_os = "linux"))]
    Rds = libc::AF_RDS,
    Sna = libc::AF_SNA,
    #[cfg(any(target_os = "android", target_os = "linux"))]
    Irda = libc::AF_IRDA,
    #[cfg(any(target_os = "android", target_os = "linux"))]
    Pppox = libc::AF_PPPOX,
    #[cfg(any(target_os = "android", target_os = "linux"))]
    Wanpipe = libc::AF_WANPIPE,
    #[cfg(any(target_os = "android", target_os = "linux"))]
    Llc = libc::AF_LLC,
    #[cfg(target_os = "linux")]
    Ib = libc::AF_IB,
    #[cfg(target_os = "linux")]
    Mpls = libc::AF_MPLS,
    #[cfg(any(target_os = "android", target_os = "linux"))]
    Can = libc::AF_CAN,
    #[cfg(any(target_os = "android", target_os = "linux"))]
    Tipc = libc::AF_TIPC,
    #[cfg(not(any(target_os = "ios", target_os = "macos")))]
    Bluetooth = libc::AF_BLUETOOTH,
    #[cfg(any(target_os = "android", target_os = "linux"))]
    Iucv = libc::AF_IUCV,
    #[cfg(any(target_os = "android", target_os = "linux"))]
    RxRpc = libc::AF_RXRPC,
    Isdn = libc::AF_ISDN,
    #[cfg(any(target_os = "android", target_os = "linux"))]
    Phonet = libc::AF_PHONET,
    #[cfg(any(target_os = "android", target_os = "linux"))]
    Ieee802154 = libc::AF_IEEE802154,
    #[cfg(any(target_os = "android", target_os = "linux"))]
    Caif = libc::AF_CAIF,
    /// Interface to kernel crypto API
    #[cfg(any(target_os = "android", target_os = "linux"))]
    Alg = libc::AF_ALG,
    #[cfg(target_os = "linux")]
    Nfc = libc::AF_NFC,
    #[cfg(target_os = "linux")]
    Vsock = libc::AF_VSOCK,
    #[cfg(any(target_os = "dragonfly",
              target_os = "freebsd",
              target_os = "ios",
              target_os = "macos",
              target_os = "netbsd",
              target_os = "openbsd"))]
    ImpLink = libc::AF_IMPLINK,
    #[cfg(any(target_os = "dragonfly",
              target_os = "freebsd",
              target_os = "ios",
              target_os = "macos",
              target_os = "netbsd",
              target_os = "openbsd"))]
    Pup = libc::AF_PUP,
    #[cfg(any(target_os = "dragonfly",
              target_os = "freebsd",
              target_os = "ios",
              target_os = "macos",
              target_os = "netbsd",
              target_os = "openbsd"))]
    Chaos = libc::AF_CHAOS,
    #[cfg(any(target_os = "ios",
              target_os = "macos",
              target_os = "netbsd",
              target_os = "openbsd"))]
    Ns = libc::AF_NS,
    #[cfg(any(target_os = "dragonfly",
              target_os = "freebsd",
              target_os = "ios",
              target_os = "macos",
              target_os = "netbsd",
              target_os = "openbsd"))]
    Iso = libc::AF_ISO,
    #[cfg(any(target_os = "dragonfly",
              target_os = "freebsd",
              target_os = "ios",
              target_os = "macos",
              target_os = "netbsd",
              target_os = "openbsd"))]
    Datakit = libc::AF_DATAKIT,
    #[cfg(any(target_os = "dragonfly",
              target_os = "freebsd",
              target_os = "ios",
              target_os = "macos",
              target_os = "netbsd",
              target_os = "openbsd"))]
    Ccitt = libc::AF_CCITT,
    #[cfg(any(target_os = "dragonfly",
              target_os = "freebsd",
              target_os = "ios",
              target_os = "macos",
              target_os = "netbsd",
              target_os = "openbsd"))]
    Dli = libc::AF_DLI,
    #[cfg(any(target_os = "dragonfly",
              target_os = "freebsd",
              target_os = "ios",
              target_os = "macos",
              target_os = "netbsd",
              target_os = "openbsd"))]
    Lat = libc::AF_LAT,
    #[cfg(any(target_os = "dragonfly",
              target_os = "freebsd",
              target_os = "ios",
              target_os = "macos",
              target_os = "netbsd",
              target_os = "openbsd"))]
    Hylink = libc::AF_HYLINK,
    #[cfg(any(target_os = "dragonfly",
              target_os = "freebsd",
              target_os = "ios",
              target_os = "macos",
              target_os = "netbsd",
              target_os = "openbsd"))]
    Link = libc::AF_LINK,
    #[cfg(any(target_os = "dragonfly",
              target_os = "freebsd",
              target_os = "ios",
              target_os = "macos",
              target_os = "netbsd",
              target_os = "openbsd"))]
    Coip = libc::AF_COIP,
    #[cfg(any(target_os = "dragonfly",
              target_os = "freebsd",
              target_os = "ios",
              target_os = "macos",
              target_os = "netbsd",
              target_os = "openbsd"))]
    Cnt = libc::AF_CNT,
    #[cfg(any(target_os = "dragonfly",
              target_os = "freebsd",
              target_os = "ios",
              target_os = "macos",
              target_os = "netbsd",
              target_os = "openbsd"))]
    Natm = libc::AF_NATM,
}

impl AddressFamily {
    /// Create a new `AddressFamily` from an integer value retrieved from `libc`, usually from
    /// the `sa_family` field of a `sockaddr`.
    ///
    /// Currently only supports these address families: Unix, Inet (v4 & v6), Netlink
    /// and System. Returns None for unsupported or unknown address families.
    pub fn from_i32(family: i32) -> Option<AddressFamily> {
        match family {
            libc::AF_UNIX => Some(AddressFamily::Unix),
            libc::AF_INET => Some(AddressFamily::Inet),
            libc::AF_INET6 => Some(AddressFamily::Inet6),
            #[cfg(any(target_os = "android", target_os = "linux"))]
            libc::AF_NETLINK => Some(AddressFamily::Netlink),
            #[cfg(any(target_os = "macos", target_os = "macos"))]
            libc::AF_SYSTEM => Some(AddressFamily::System),
            _ => None
        }
    }
}

#[derive(Copy)]
pub enum InetAddr {
    V4(libc::sockaddr_in),
    V6(libc::sockaddr_in6),
}

impl InetAddr {
    pub fn from_std(std: &net::SocketAddr) -> InetAddr {
        match *std {
            net::SocketAddr::V4(ref addr) => {
                InetAddr::V4(libc::sockaddr_in {
                    sin_family: AddressFamily::Inet as sa_family_t,
                    sin_port: addr.port().to_be(),  // network byte order
                    sin_addr: Ipv4Addr::from_std(addr.ip()).0,
                    .. unsafe { mem::zeroed() }
                })
            }
            net::SocketAddr::V6(ref addr) => {
                InetAddr::V6(libc::sockaddr_in6 {
                    sin6_family: AddressFamily::Inet6 as sa_family_t,
                    sin6_port: addr.port().to_be(),  // network byte order
                    sin6_addr: Ipv6Addr::from_std(addr.ip()).0,
                    sin6_flowinfo: addr.flowinfo(),  // host byte order
                    sin6_scope_id: addr.scope_id(),  // host byte order
                    .. unsafe { mem::zeroed() }
                })
            }
        }
    }

    pub fn new(ip: IpAddr, port: u16) -> InetAddr {
        match ip {
            IpAddr::V4(ref ip) => {
                InetAddr::V4(libc::sockaddr_in {
                    sin_family: AddressFamily::Inet as sa_family_t,
                    sin_port: port.to_be(),
                    sin_addr: ip.0,
                    .. unsafe { mem::zeroed() }
                })
            }
            IpAddr::V6(ref ip) => {
                InetAddr::V6(libc::sockaddr_in6 {
                    sin6_family: AddressFamily::Inet6 as sa_family_t,
                    sin6_port: port.to_be(),
                    sin6_addr: ip.0,
                    .. unsafe { mem::zeroed() }
                })
            }
        }
    }
    /// Gets the IP address associated with this socket address.
    pub fn ip(&self) -> IpAddr {
        match *self {
            InetAddr::V4(ref sa) => IpAddr::V4(Ipv4Addr(sa.sin_addr)),
            InetAddr::V6(ref sa) => IpAddr::V6(Ipv6Addr(sa.sin6_addr)),
        }
    }

    /// Gets the port number associated with this socket address
    pub fn port(&self) -> u16 {
        match *self {
            InetAddr::V6(ref sa) => u16::from_be(sa.sin6_port),
            InetAddr::V4(ref sa) => u16::from_be(sa.sin_port),
        }
    }

    pub fn to_std(&self) -> net::SocketAddr {
        match *self {
            InetAddr::V4(ref sa) => net::SocketAddr::V4(
                net::SocketAddrV4::new(
                    Ipv4Addr(sa.sin_addr).to_std(),
                    self.port())),
            InetAddr::V6(ref sa) => net::SocketAddr::V6(
                net::SocketAddrV6::new(
                    Ipv6Addr(sa.sin6_addr).to_std(),
                    self.port(),
                    sa.sin6_flowinfo,
                    sa.sin6_scope_id)),
        }
    }

    pub fn to_str(&self) -> String {
        format!("{}", self)
    }
}

impl PartialEq for InetAddr {
    fn eq(&self, other: &InetAddr) -> bool {
        match (*self, *other) {
            (InetAddr::V4(ref a), InetAddr::V4(ref b)) => {
                a.sin_port == b.sin_port &&
                    a.sin_addr.s_addr == b.sin_addr.s_addr
            }
            (InetAddr::V6(ref a), InetAddr::V6(ref b)) => {
                a.sin6_port == b.sin6_port &&
                    a.sin6_addr.s6_addr == b.sin6_addr.s6_addr &&
                    a.sin6_flowinfo == b.sin6_flowinfo &&
                    a.sin6_scope_id == b.sin6_scope_id
            }
            _ => false,
        }
    }
}

impl Eq for InetAddr {
}

impl hash::Hash for InetAddr {
    fn hash<H: hash::Hasher>(&self, s: &mut H) {
        match *self {
            InetAddr::V4(ref a) => {
                ( a.sin_family,
                  a.sin_port,
                  a.sin_addr.s_addr ).hash(s)
            }
            InetAddr::V6(ref a) => {
                ( a.sin6_family,
                  a.sin6_port,
                  &a.sin6_addr.s6_addr,
                  a.sin6_flowinfo,
                  a.sin6_scope_id ).hash(s)
            }
        }
    }
}

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

impl fmt::Display for InetAddr {
    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
        match *self {
            InetAddr::V4(_) => write!(f, "{}:{}", self.ip(), self.port()),
            InetAddr::V6(_) => write!(f, "[{}]:{}", self.ip(), self.port()),
        }
    }
}

/*
 *
 * ===== IpAddr =====
 *
 */

pub enum IpAddr {
    V4(Ipv4Addr),
    V6(Ipv6Addr),
}

impl IpAddr {
    /// Create a new IpAddr that contains an IPv4 address.
    ///
    /// The result will represent the IP address a.b.c.d
    pub fn new_v4(a: u8, b: u8, c: u8, d: u8) -> IpAddr {
        IpAddr::V4(Ipv4Addr::new(a, b, c, d))
    }

    /// Create a new IpAddr that contains an IPv6 address.
    ///
    /// The result will represent the IP address a:b:c:d:e:f
    pub fn new_v6(a: u16, b: u16, c: u16, d: u16, e: u16, f: u16, g: u16, h: u16) -> IpAddr {
        IpAddr::V6(Ipv6Addr::new(a, b, c, d, e, f, g, h))
    }

    /*
    pub fn from_std(std: &net::IpAddr) -> IpAddr {
        match *std {
            net::IpAddr::V4(ref std) => IpAddr::V4(Ipv4Addr::from_std(std)),
            net::IpAddr::V6(ref std) => IpAddr::V6(Ipv6Addr::from_std(std)),
        }
    }

    pub fn to_std(&self) -> net::IpAddr {
        match *self {
            IpAddr::V4(ref ip) => net::IpAddr::V4(ip.to_std()),
            IpAddr::V6(ref ip) => net::IpAddr::V6(ip.to_std()),
        }
    }
    */
}

impl fmt::Display for IpAddr {
    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
        match *self {
            IpAddr::V4(ref v4) => v4.fmt(f),
            IpAddr::V6(ref v6) => v6.fmt(f)
        }
    }
}

/*
 *
 * ===== Ipv4Addr =====
 *
 */

#[derive(Copy)]
pub struct Ipv4Addr(pub libc::in_addr);

impl Ipv4Addr {
    pub fn new(a: u8, b: u8, c: u8, d: u8) -> Ipv4Addr {
        let ip = (((a as u32) << 24) |
                  ((b as u32) << 16) |
                  ((c as u32) <<  8) |
                  ((d as u32) <<  0)).to_be();

        Ipv4Addr(libc::in_addr { s_addr: ip })
    }

    pub fn from_std(std: &net::Ipv4Addr) -> Ipv4Addr {
        let bits = std.octets();
        Ipv4Addr::new(bits[0], bits[1], bits[2], bits[3])
    }

    pub fn any() -> Ipv4Addr {
        Ipv4Addr(libc::in_addr { s_addr: libc::INADDR_ANY })
    }

    pub fn octets(&self) -> [u8; 4] {
        let bits = u32::from_be(self.0.s_addr);
        [(bits >> 24) as u8, (bits >> 16) as u8, (bits >> 8) as u8, bits as u8]
    }

    pub fn to_std(&self) -> net::Ipv4Addr {
        let bits = self.octets();
        net::Ipv4Addr::new(bits[0], bits[1], bits[2], bits[3])
    }
}

impl PartialEq for Ipv4Addr {
    fn eq(&self, other: &Ipv4Addr) -> bool {
        self.0.s_addr == other.0.s_addr
    }
}

impl Eq for Ipv4Addr {
}

impl hash::Hash for Ipv4Addr {
    fn hash<H: hash::Hasher>(&self, s: &mut H) {
        self.0.s_addr.hash(s)
    }
}

impl Clone for Ipv4Addr {
    fn clone(&self) -> Ipv4Addr {
        *self
    }
}

impl fmt::Display for Ipv4Addr {
    fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
        let octets = self.octets();
        write!(fmt, "{}.{}.{}.{}", octets[0], octets[1], octets[2], octets[3])
    }
}

/*
 *
 * ===== Ipv6Addr =====
 *
 */

#[derive(Clone, Copy)]
pub struct Ipv6Addr(pub libc::in6_addr);

// Note that IPv6 addresses are stored in big endian order on all architectures.
// See https://tools.ietf.org/html/rfc1700 or consult your favorite search
// engine.

macro_rules! to_u8_array {
    ($($num:ident),*) => {
        [ $(($num>>8) as u8, ($num&0xff) as u8,)* ]
    }
}

macro_rules! to_u16_array {
    ($slf:ident, $($first:expr, $second:expr),*) => {
        [$( (($slf.0.s6_addr[$first] as u16) << 8) + $slf.0.s6_addr[$second] as u16,)*]
    }
}

impl Ipv6Addr {
    pub fn new(a: u16, b: u16, c: u16, d: u16, e: u16, f: u16, g: u16, h: u16) -> Ipv6Addr {
        let mut in6_addr_var: libc::in6_addr = unsafe{mem::uninitialized()};
        in6_addr_var.s6_addr = to_u8_array!(a,b,c,d,e,f,g,h);
        Ipv6Addr(in6_addr_var)
    }

    pub fn from_std(std: &net::Ipv6Addr) -> Ipv6Addr {
        let s = std.segments();
        Ipv6Addr::new(s[0], s[1], s[2], s[3], s[4], s[5], s[6], s[7])
    }

    /// Return the eight 16-bit segments that make up this address
    pub fn segments(&self) -> [u16; 8] {
        to_u16_array!(self, 0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15)
    }

    pub fn to_std(&self) -> net::Ipv6Addr {
        let s = self.segments();
        net::Ipv6Addr::new(s[0], s[1], s[2], s[3], s[4], s[5], s[6], s[7])
    }
}

impl fmt::Display for Ipv6Addr {
    fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
        self.to_std().fmt(fmt)
    }
}

/*
 *
 * ===== UnixAddr =====
 *
 */

/// A wrapper around `sockaddr_un`.
///
/// This also tracks the length of `sun_path` address (excluding
/// a terminating null), because it may not be null-terminated.  For example,
/// unconnected and Linux abstract sockets are never null-terminated, and POSIX
/// does not require that `sun_len` include the terminating null even for normal
/// sockets.  Note that the actual sockaddr length is greater by
/// `offset_of!(libc::sockaddr_un, sun_path)`
#[derive(Copy)]
pub struct UnixAddr(pub libc::sockaddr_un, pub usize);

impl UnixAddr {
    /// Create a new sockaddr_un representing a filesystem path.
    pub fn new<P: ?Sized + NixPath>(path: &P) -> Result<UnixAddr> {
        try!(path.with_nix_path(|cstr| {
            unsafe {
                let mut ret = libc::sockaddr_un {
                    sun_family: AddressFamily::Unix as sa_family_t,
                    .. mem::zeroed()
                };

                let bytes = cstr.to_bytes();

                if bytes.len() > ret.sun_path.len() {
                    return Err(Error::Sys(Errno::ENAMETOOLONG));
                }

                ptr::copy_nonoverlapping(bytes.as_ptr(),
                                         ret.sun_path.as_mut_ptr() as *mut u8,
                                         bytes.len());

                Ok(UnixAddr(ret, bytes.len()))
            }
        }))
    }

    /// Create a new `sockaddr_un` representing an address in the "abstract namespace".
    ///
    /// The leading null byte for the abstract namespace is automatically added;
    /// thus the input `path` is expected to be the bare name, not null-prefixed.
    /// This is a Linux-specific extension, primarily used to allow chrooted
    /// processes to communicate with processes having a different filesystem view.
    #[cfg(any(target_os = "android", target_os = "linux"))]
    pub fn new_abstract(path: &[u8]) -> Result<UnixAddr> {
        unsafe {
            let mut ret = libc::sockaddr_un {
                sun_family: AddressFamily::Unix as sa_family_t,
                .. mem::zeroed()
            };

            if path.len() + 1 > ret.sun_path.len() {
                return Err(Error::Sys(Errno::ENAMETOOLONG));
            }

            // Abstract addresses are represented by sun_path[0] ==
            // b'\0', so copy starting one byte in.
            ptr::copy_nonoverlapping(path.as_ptr(),
                                     ret.sun_path.as_mut_ptr().offset(1) as *mut u8,
                                     path.len());

            Ok(UnixAddr(ret, path.len() + 1))
        }
    }

    fn sun_path(&self) -> &[u8] {
        unsafe { slice::from_raw_parts(self.0.sun_path.as_ptr() as *const u8, self.1) }
    }

    /// If this address represents a filesystem path, return that path.
    pub fn path(&self) -> Option<&Path> {
        if self.1 == 0 || self.0.sun_path[0] == 0 {
            // unnamed or abstract
            None
        } else {
            let p = self.sun_path();
            // POSIX only requires that `sun_len` be at least long enough to
            // contain the pathname, and it need not be null-terminated.  So we
            // need to create a string that is the shorter of the
            // null-terminated length or the full length.
            let ptr = &self.0.sun_path as *const libc::c_char;
            let reallen = unsafe { libc::strnlen(ptr, p.len()) };
            Some(Path::new(<OsStr as OsStrExt>::from_bytes(&p[..reallen])))
        }
    }

    /// If this address represents an abstract socket, return its name.
    ///
    /// For abstract sockets only the bare name is returned, without the
    /// leading null byte. `None` is returned for unnamed or path-backed sockets.
    #[cfg(any(target_os = "android", target_os = "linux"))]
    pub fn as_abstract(&self) -> Option<&[u8]> {
        if self.1 >= 1 && self.0.sun_path[0] == 0 {
            Some(&self.sun_path()[1..])
        } else {
            // unnamed or filesystem path
            None
        }
    }
}

impl PartialEq for UnixAddr {
    fn eq(&self, other: &UnixAddr) -> bool {
        self.sun_path() == other.sun_path()
    }
}

impl Eq for UnixAddr {
}

impl hash::Hash for UnixAddr {
    fn hash<H: hash::Hasher>(&self, s: &mut H) {
        ( self.0.sun_family, self.sun_path() ).hash(s)
    }
}

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

impl fmt::Display for UnixAddr {
    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
        if self.1 == 0 {
            f.write_str("<unbound UNIX socket>")
        } else if let Some(path) = self.path() {
            path.display().fmt(f)
        } else {
            let display = String::from_utf8_lossy(&self.sun_path()[1..]);
            write!(f, "@{}", display)
        }
    }
}

/*
 *
 * ===== Sock addr =====
 *
 */

/// Represents a socket address
#[derive(Copy)]
pub enum SockAddr {
    Inet(InetAddr),
    Unix(UnixAddr),
    #[cfg(any(target_os = "android", target_os = "linux"))]
    Netlink(NetlinkAddr),
    #[cfg(any(target_os = "ios", target_os = "macos"))]
    SysControl(SysControlAddr),
}

impl SockAddr {
    pub fn new_inet(addr: InetAddr) -> SockAddr {
        SockAddr::Inet(addr)
    }

    pub fn new_unix<P: ?Sized + NixPath>(path: &P) -> Result<SockAddr> {
        Ok(SockAddr::Unix(try!(UnixAddr::new(path))))
    }

    #[cfg(any(target_os = "android", target_os = "linux"))]
    pub fn new_netlink(pid: u32, groups: u32) -> SockAddr {
        SockAddr::Netlink(NetlinkAddr::new(pid, groups))
    }

    #[cfg(any(target_os = "ios", target_os = "macos"))]
    pub fn new_sys_control(sockfd: RawFd, name: &str, unit: u32) -> Result<SockAddr> {
        SysControlAddr::from_name(sockfd, name, unit).map(|a| SockAddr::SysControl(a))
    }

    pub fn family(&self) -> AddressFamily {
        match *self {
            SockAddr::Inet(InetAddr::V4(..)) => AddressFamily::Inet,
            SockAddr::Inet(InetAddr::V6(..)) => AddressFamily::Inet6,
            SockAddr::Unix(..) => AddressFamily::Unix,
            #[cfg(any(target_os = "android", target_os = "linux"))]
            SockAddr::Netlink(..) => AddressFamily::Netlink,
            #[cfg(any(target_os = "ios", target_os = "macos"))]
            SockAddr::SysControl(..) => AddressFamily::System,
        }
    }

    pub fn to_str(&self) -> String {
        format!("{}", self)
    }

    /// Creates a `SockAddr` struct from libc's sockaddr.
    ///
    /// Supports only the following address families: Unix, Inet (v4 & v6), Netlink and System.
    /// Returns None for unsupported families.
    pub unsafe fn from_libc_sockaddr(addr: *const libc::sockaddr) -> Option<SockAddr> {
        if addr.is_null() {
            None
        } else {
            match AddressFamily::from_i32((*addr).sa_family as i32) {
                Some(AddressFamily::Unix) => None,
                Some(AddressFamily::Inet) => Some(SockAddr::Inet(
                    InetAddr::V4(*(addr as *const libc::sockaddr_in)))),
                Some(AddressFamily::Inet6) => Some(SockAddr::Inet(
                    InetAddr::V6(*(addr as *const libc::sockaddr_in6)))),
                #[cfg(any(target_os = "android", target_os = "linux"))]
                Some(AddressFamily::Netlink) => Some(SockAddr::Netlink(
                    NetlinkAddr(*(addr as *const libc::sockaddr_nl)))),
                #[cfg(any(target_os = "ios", target_os = "macos"))]
                Some(AddressFamily::System) => Some(SockAddr::SysControl(
                    SysControlAddr(*(addr as *const sys_control::sockaddr_ctl)))),
                // Other address families are currently not supported and simply yield a None
                // entry instead of a proper conversion to a `SockAddr`.
                Some(_) => None,
                None => None,
            }
        }
    }

    pub unsafe fn as_ffi_pair(&self) -> (&libc::sockaddr, libc::socklen_t) {
        match *self {
            SockAddr::Inet(InetAddr::V4(ref addr)) => (mem::transmute(addr), mem::size_of::<libc::sockaddr_in>() as libc::socklen_t),
            SockAddr::Inet(InetAddr::V6(ref addr)) => (mem::transmute(addr), mem::size_of::<libc::sockaddr_in6>() as libc::socklen_t),
            SockAddr::Unix(UnixAddr(ref addr, len)) => (mem::transmute(addr), (len + offset_of!(libc::sockaddr_un, sun_path)) as libc::socklen_t),
            #[cfg(any(target_os = "android", target_os = "linux"))]
            SockAddr::Netlink(NetlinkAddr(ref sa)) => (mem::transmute(sa), mem::size_of::<libc::sockaddr_nl>() as libc::socklen_t),
            #[cfg(any(target_os = "ios", target_os = "macos"))]
            SockAddr::SysControl(SysControlAddr(ref sa)) => (mem::transmute(sa), mem::size_of::<sys_control::sockaddr_ctl>() as libc::socklen_t),
        }
    }
}

impl PartialEq for SockAddr {
    fn eq(&self, other: &SockAddr) -> bool {
        match (*self, *other) {
            (SockAddr::Inet(ref a), SockAddr::Inet(ref b)) => {
                a == b
            }
            (SockAddr::Unix(ref a), SockAddr::Unix(ref b)) => {
                a == b
            }
            #[cfg(any(target_os = "android", target_os = "linux"))]
            (SockAddr::Netlink(ref a), SockAddr::Netlink(ref b)) => {
                a == b
            }
            _ => false,
        }
    }
}

impl Eq for SockAddr {
}

impl hash::Hash for SockAddr {
    fn hash<H: hash::Hasher>(&self, s: &mut H) {
        match *self {
            SockAddr::Inet(ref a) => a.hash(s),
            SockAddr::Unix(ref a) => a.hash(s),
            #[cfg(any(target_os = "android", target_os = "linux"))]
            SockAddr::Netlink(ref a) => a.hash(s),
            #[cfg(any(target_os = "ios", target_os = "macos"))]
            SockAddr::SysControl(ref a) => a.hash(s),
        }
    }
}

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

impl fmt::Display for SockAddr {
    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
        match *self {
            SockAddr::Inet(ref inet) => inet.fmt(f),
            SockAddr::Unix(ref unix) => unix.fmt(f),
            #[cfg(any(target_os = "android", target_os = "linux"))]
            SockAddr::Netlink(ref nl) => nl.fmt(f),
            #[cfg(any(target_os = "ios", target_os = "macos"))]
            SockAddr::SysControl(ref sc) => sc.fmt(f),
        }
    }
}

#[cfg(any(target_os = "android", target_os = "linux"))]
pub mod netlink {
    use ::sys::socket::addr::{AddressFamily};
    use libc::{sa_family_t, sockaddr_nl};
    use std::{fmt, mem};
    use std::hash::{Hash, Hasher};

    #[derive(Copy, Clone)]
    pub struct NetlinkAddr(pub sockaddr_nl);

    // , PartialEq, Eq, Debug, Hash
    impl PartialEq for NetlinkAddr {
        fn eq(&self, other: &Self) -> bool {
            let (inner, other) = (self.0, other.0);
            (inner.nl_family, inner.nl_pid, inner.nl_groups) ==
            (other.nl_family, other.nl_pid, other.nl_groups)
        }
    }

    impl Eq for NetlinkAddr {}

    impl Hash for NetlinkAddr {
        fn hash<H: Hasher>(&self, s: &mut H) {
            let inner = self.0;
            (inner.nl_family, inner.nl_pid, inner.nl_groups).hash(s);
        }
    }


    impl NetlinkAddr {
        pub fn new(pid: u32, groups: u32) -> NetlinkAddr {
            let mut addr: sockaddr_nl = unsafe { mem::zeroed() };
            addr.nl_family = AddressFamily::Netlink as sa_family_t;
            addr.nl_pid = pid;
            addr.nl_groups = groups;

            NetlinkAddr(addr)
        }

        pub fn pid(&self) -> u32 {
            self.0.nl_pid
        }

        pub fn groups(&self) -> u32 {
            self.0.nl_groups
        }
    }

    impl fmt::Display for NetlinkAddr {
        fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
            write!(f, "pid: {} groups: {}", self.pid(), self.groups())
        }
    }
}

#[cfg(any(target_os = "ios", target_os = "macos"))]
pub mod sys_control {
    use ::sys::socket::addr::{AddressFamily};
    use libc::{self, c_uchar, uint16_t, uint32_t};
    use std::{fmt, mem};
    use std::hash::{Hash, Hasher};
    use std::os::unix::io::RawFd;
    use {Errno, Error, Result};

    #[repr(C)]
    pub struct ctl_ioc_info {
        pub ctl_id: uint32_t,
        pub ctl_name: [c_uchar; MAX_KCTL_NAME],
    }

    const CTL_IOC_MAGIC: u8 = 'N' as u8;
    const CTL_IOC_INFO: u8 = 3;
    const MAX_KCTL_NAME: usize = 96;

    ioctl!(readwrite ctl_info with CTL_IOC_MAGIC, CTL_IOC_INFO; ctl_ioc_info);

    #[repr(C)]
    #[derive(Copy, Clone)]
    pub struct sockaddr_ctl {
        pub sc_len: c_uchar,
        pub sc_family: c_uchar,
        pub ss_sysaddr: uint16_t,
        pub sc_id: uint32_t,
        pub sc_unit: uint32_t,
        pub sc_reserved: [uint32_t; 5],
    }

    #[derive(Copy, Clone)]
    pub struct SysControlAddr(pub sockaddr_ctl);

    // , PartialEq, Eq, Debug, Hash
    impl PartialEq for SysControlAddr {
        fn eq(&self, other: &Self) -> bool {
            let (inner, other) = (self.0, other.0);
            (inner.sc_id, inner.sc_unit) ==
            (other.sc_id, other.sc_unit)
        }
    }

    impl Eq for SysControlAddr {}

    impl Hash for SysControlAddr {
        fn hash<H: Hasher>(&self, s: &mut H) {
            let inner = self.0;
            (inner.sc_id, inner.sc_unit).hash(s);
        }
    }


    impl SysControlAddr {
        pub fn new(id: u32, unit: u32) -> SysControlAddr {
            let addr = sockaddr_ctl {
                sc_len: mem::size_of::<sockaddr_ctl>() as c_uchar,
                sc_family: AddressFamily::System as c_uchar,
                ss_sysaddr: libc::AF_SYS_CONTROL as uint16_t,
                sc_id: id,
                sc_unit: unit,
                sc_reserved: [0; 5]
            };

            SysControlAddr(addr)
        }

        pub fn from_name(sockfd: RawFd, name: &str, unit: u32) -> Result<SysControlAddr> {
            if name.len() > MAX_KCTL_NAME {
                return Err(Error::Sys(Errno::ENAMETOOLONG));
            }

            let mut ctl_name = [0; MAX_KCTL_NAME];
            ctl_name[..name.len()].clone_from_slice(name.as_bytes());
            let mut info = ctl_ioc_info { ctl_id: 0, ctl_name: ctl_name };

            unsafe { try!(ctl_info(sockfd, &mut info)); }

            Ok(SysControlAddr::new(info.ctl_id, unit))
        }

        pub fn id(&self) -> u32 {
            self.0.sc_id
        }

        pub fn unit(&self) -> u32 {
            self.0.sc_unit
        }
    }

    impl fmt::Display for SysControlAddr {
        fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
            write!(f, "id: {} unit: {}", self.id(), self.unit())
        }
    }
}