Improve ergonomics of getsockopt / setsockopt

3 files changed, 369 insertions, 125 deletions

diff --git a/src/sys/socket/consts.rs b/src/sys/socket/consts.rs
index e23098b6..39bcd733 100644
--- a/src/sys/socket/consts.rs
+++ b/src/sys/socket/consts.rs
@@ -19,64 +19,62 @@ mod os {
     pub const SOCK_RAW: SockType = 3;
     pub const SOCK_RDM: SockType = 4;
 
-    pub type SockLevel = c_int;
-
-    pub const SOL_IP: SockLevel     = 0;
-    pub const IPPROTO_IP: SockLevel = SOL_IP;
-    pub const SOL_SOCKET: SockLevel = 1;
-    pub const SOL_TCP: SockLevel    = 6;
-    pub const IPPROTO_TCP: SockLevel = SOL_TCP;
-    pub const SOL_UDP: SockLevel    = 17;
-    pub const SOL_IPV6: SockLevel   = 41;
-
-    pub type SockOpt = c_int;
-
-    pub const SO_ACCEPTCONN: SockOpt = 30;
-    pub const SO_BINDTODEVICE: SockOpt = 25;
-    pub const SO_BROADCAST: SockOpt = 6;
-    pub const SO_BSDCOMPAT: SockOpt = 14;
-    pub const SO_DEBUG: SockOpt = 1;
-    pub const SO_DOMAIN: SockOpt = 39;
-    pub const SO_ERROR: SockOpt = 4;
-    pub const SO_DONTROUTE: SockOpt = 5;
-    pub const SO_KEEPALIVE: SockOpt = 9;
-    pub const SO_LINGER: SockOpt = 13;
-    pub const SO_MARK: SockOpt = 36;
-    pub const SO_OOBINLINE: SockOpt = 10;
-    pub const SO_PASSCRED: SockOpt = 16;
-    pub const SO_PEEK_OFF: SockOpt = 42;
-    pub const SO_PEERCRED: SockOpt = 17;
-    pub const SO_PRIORITY: SockOpt = 12;
-    pub const SO_PROTOCOL: SockOpt = 38;
-    pub const SO_RCVBUF: SockOpt = 8;
-    pub const SO_RCVBUFFORCE: SockOpt = 33;
-    pub const SO_RCVLOWAT: SockOpt = 18;
-    pub const SO_SNDLOWAT: SockOpt = 19;
-    pub const SO_RCVTIMEO: SockOpt = 20;
-    pub const SO_SNDTIMEO: SockOpt = 21;
-    pub const SO_REUSEADDR: SockOpt = 2;
-    pub const SO_REUSEPORT: SockOpt = 15;
-    pub const SO_RXQ_OVFL: SockOpt = 40;
-    pub const SO_SNDBUF: SockOpt = 7;
-    pub const SO_SNDBUFFORCE: SockOpt = 32;
-    pub const SO_TIMESTAMP: SockOpt = 29;
-    pub const SO_TYPE: SockOpt = 3;
-    pub const SO_BUSY_POLL: SockOpt = 46;
+    pub const SOL_IP: c_int     = 0;
+    pub const SOL_SOCKET: c_int = 1;
+    pub const SOL_TCP: c_int    = 6;
+    pub const SOL_UDP: c_int    = 17;
+    pub const SOL_IPV6: c_int   = 41;
+    pub const IPPROTO_IP: c_int = SOL_IP;
+    pub const IPPROTO_IPV6: c_int = SOL_IPV6;
+    pub const IPPROTO_TCP: c_int = SOL_TCP;
+    pub const IPPROTO_UDP: c_int = SOL_UDP;
+
+    pub const SO_ACCEPTCONN: c_int = 30;
+    pub const SO_BINDTODEVICE: c_int = 25;
+    pub const SO_BROADCAST: c_int = 6;
+    pub const SO_BSDCOMPAT: c_int = 14;
+    pub const SO_DEBUG: c_int = 1;
+    pub const SO_DOMAIN: c_int = 39;
+    pub const SO_ERROR: c_int = 4;
+    pub const SO_DONTROUTE: c_int = 5;
+    pub const SO_KEEPALIVE: c_int = 9;
+    pub const SO_LINGER: c_int = 13;
+    pub const SO_MARK: c_int = 36;
+    pub const SO_OOBINLINE: c_int = 10;
+    pub const SO_PASSCRED: c_int = 16;
+    pub const SO_PEEK_OFF: c_int = 42;
+    pub const SO_PEERCRED: c_int = 17;
+    pub const SO_PRIORITY: c_int = 12;
+    pub const SO_PROTOCOL: c_int = 38;
+    pub const SO_RCVBUF: c_int = 8;
+    pub const SO_RCVBUFFORCE: c_int = 33;
+    pub const SO_RCVLOWAT: c_int = 18;
+    pub const SO_SNDLOWAT: c_int = 19;
+    pub const SO_RCVTIMEO: c_int = 20;
+    pub const SO_SNDTIMEO: c_int = 21;
+    pub const SO_REUSEADDR: c_int = 2;
+    pub const SO_REUSEPORT: c_int = 15;
+    pub const SO_RXQ_OVFL: c_int = 40;
+    pub const SO_SNDBUF: c_int = 7;
+    pub const SO_SNDBUFFORCE: c_int = 32;
+    pub const SO_TIMESTAMP: c_int = 29;
+    pub const SO_TYPE: c_int = 3;
+    pub const SO_BUSY_POLL: c_int = 46;
 
     // Socket options for TCP sockets
-    pub const TCP_NODELAY: SockOpt = 1;
-    pub const TCP_MAXSEG: SockOpt = 2;
-    pub const TCP_CORK: SockOpt = 3;
+    pub const TCP_NODELAY: c_int = 1;
+    pub const TCP_MAXSEG: c_int = 2;
+    pub const TCP_CORK: c_int = 3;
 
     // Socket options for the IP layer of the socket
-    pub const IP_MULTICAST_IF: SockOpt = 32;
+    pub const IP_MULTICAST_IF: c_int = 32;
 
     pub type IpMulticastTtl = uint8_t;
 
-    pub const IP_MULTICAST_TTL: SockOpt = 33;
-    pub const IP_MULTICAST_LOOP: SockOpt = 34;
-    pub const IP_ADD_MEMBERSHIP: SockOpt = 35;
-    pub const IP_DROP_MEMBERSHIP: SockOpt = 36;
+    pub const IP_MULTICAST_TTL: c_int = 33;
+    pub const IP_MULTICAST_LOOP: c_int = 34;
+    pub const IP_ADD_MEMBERSHIP: c_int = 35;
+    pub const IP_DROP_MEMBERSHIP: c_int = 36;
 
     pub type InAddrT = u32;
 
@@ -111,67 +109,64 @@ mod os {
     pub const SOCK_RAW: SockType = 3;
     pub const SOCK_RDM: SockType = 4;
 
-    pub type SockLevel = c_int;
-
-    pub const SOL_SOCKET: SockLevel = 0xffff;
-    pub const IPPROTO_IP: SockLevel = 0;
-    pub const IPPROTO_TCP: SockLevel = 6;
-    pub const IPPROTO_UDP: SockLevel = 17;
-
-    pub type SockOpt = c_int;
-
-    pub const SO_ACCEPTCONN: SockOpt          = 0x0002;
-    pub const SO_BROADCAST: SockOpt           = 0x0020;
-    pub const SO_DEBUG: SockOpt               = 0x0001;
-    pub const SO_DONTTRUNC: SockOpt           = 0x2000;
-    pub const SO_ERROR: SockOpt               = 0x1007;
-    pub const SO_DONTROUTE: SockOpt           = 0x0010;
-    pub const SO_KEEPALIVE: SockOpt           = 0x0008;
-    pub const SO_LABEL: SockOpt               = 0x1010;
-    pub const SO_LINGER: SockOpt              = 0x0080;
-    pub const SO_NREAD: SockOpt               = 0x1020;
-    pub const SO_NKE: SockOpt                 = 0x1021;
-    pub const SO_NOSIGPIPE: SockOpt           = 0x1022;
-    pub const SO_NOADDRERR: SockOpt           = 0x1023;
-    pub const SO_NOTIFYCONFLICT: SockOpt      = 0x1026;
-    pub const SO_NP_EXTENSIONS: SockOpt       = 0x1083;
-    pub const SO_NWRITE: SockOpt              = 0x1024;
-    pub const SO_OOBINLINE: SockOpt           = 0x0100;
-    pub const SO_PEERLABEL: SockOpt           = 0x1011;
-    pub const SO_RCVBUF: SockOpt              = 0x1002;
-    pub const SO_RCVLOWAT: SockOpt            = 0x1004;
-    pub const SO_SNDLOWAT: SockOpt            = 0x1003;
-    pub const SO_RCVTIMEO: SockOpt            = 0x1006;
-    pub const SO_SNDTIMEO: SockOpt            = 0x1005;
-    pub const SO_RANDOMPORT: SockOpt          = 0x1082;
-    pub const SO_RESTRICTIONS: SockOpt        = 0x1081;
-    pub const SO_RESTRICT_DENYIN: SockOpt     = 0x00000001;
-    pub const SO_RESTRICT_DENYOUT: SockOpt    = 0x00000002;
-    pub const SO_REUSEADDR: SockOpt           = 0x0004;
-    pub const SO_REUSEPORT: SockOpt           = 0x0200;
-    pub const SO_REUSESHAREUID: SockOpt       = 0x1025;
-    pub const SO_SNDBUF: SockOpt              = 0x1001;
-    pub const SO_TIMESTAMP: SockOpt           = 0x0400;
-    pub const SO_TIMESTAMP_MONOTONIC: SockOpt = 0x0800;
-    pub const SO_TYPE: SockOpt                = 0x1008;
-    pub const SO_WANTMORE: SockOpt            = 0x4000;
-    pub const SO_WANTOOBFLAG: SockOpt         = 0x8000;
+    pub const SOL_SOCKET: c_int = 0xffff;
+    pub const IPPROTO_IP: c_int = 0;
+    pub const IPPROTO_IPV6: c_int = 41;
+    pub const IPPROTO_TCP: c_int = 6;
+    pub const IPPROTO_UDP: c_int = 17;
+
+    pub const SO_ACCEPTCONN: c_int          = 0x0002;
+    pub const SO_BROADCAST: c_int           = 0x0020;
+    pub const SO_DEBUG: c_int               = 0x0001;
+    pub const SO_DONTTRUNC: c_int           = 0x2000;
+    pub const SO_ERROR: c_int               = 0x1007;
+    pub const SO_DONTROUTE: c_int           = 0x0010;
+    pub const SO_KEEPALIVE: c_int           = 0x0008;
+    pub const SO_LABEL: c_int               = 0x1010;
+    pub const SO_LINGER: c_int              = 0x0080;
+    pub const SO_NREAD: c_int               = 0x1020;
+    pub const SO_NKE: c_int                 = 0x1021;
+    pub const SO_NOSIGPIPE: c_int           = 0x1022;
+    pub const SO_NOADDRERR: c_int           = 0x1023;
+    pub const SO_NOTIFYCONFLICT: c_int      = 0x1026;
+    pub const SO_NP_EXTENSIONS: c_int       = 0x1083;
+    pub const SO_NWRITE: c_int              = 0x1024;
+    pub const SO_OOBINLINE: c_int           = 0x0100;
+    pub const SO_PEERLABEL: c_int           = 0x1011;
+    pub const SO_RCVBUF: c_int              = 0x1002;
+    pub const SO_RCVLOWAT: c_int            = 0x1004;
+    pub const SO_SNDLOWAT: c_int            = 0x1003;
+    pub const SO_RCVTIMEO: c_int            = 0x1006;
+    pub const SO_SNDTIMEO: c_int            = 0x1005;
+    pub const SO_RANDOMPORT: c_int          = 0x1082;
+    pub const SO_RESTRICTIONS: c_int        = 0x1081;
+    pub const SO_RESTRICT_DENYIN: c_int     = 0x00000001;
+    pub const SO_RESTRICT_DENYOUT: c_int    = 0x00000002;
+    pub const SO_REUSEADDR: c_int           = 0x0004;
+    pub const SO_REUSEPORT: c_int           = 0x0200;
+    pub const SO_REUSESHAREUID: c_int       = 0x1025;
+    pub const SO_SNDBUF: c_int              = 0x1001;
+    pub const SO_TIMESTAMP: c_int           = 0x0400;
+    pub const SO_TIMESTAMP_MONOTONIC: c_int = 0x0800;
+    pub const SO_TYPE: c_int                = 0x1008;
+    pub const SO_WANTMORE: c_int            = 0x4000;
+    pub const SO_WANTOOBFLAG: c_int         = 0x8000;
     #[allow(overflowing_literals)]
-    pub const SO_RESTRICT_DENYSET: SockOpt    = 0x80000000;
+    pub const SO_RESTRICT_DENYSET: c_int    = 0x80000000;
 
     // Socket options for TCP sockets
-    pub const TCP_NODELAY: SockOpt = 1;
-    pub const TCP_MAXSEG: SockOpt = 2;
+    pub const TCP_NODELAY: c_int = 1;
+    pub const TCP_MAXSEG: c_int = 2;
 
     // Socket options for the IP layer of the socket
-    pub const IP_MULTICAST_IF: SockOpt = 9;
+    pub const IP_MULTICAST_IF: c_int = 9;
 
     pub type IpMulticastTtl = uint8_t;
 
-    pub const IP_MULTICAST_TTL: SockOpt = 10;
-    pub const IP_MULTICAST_LOOP: SockOpt = 11;
-    pub const IP_ADD_MEMBERSHIP: SockOpt = 12;
-    pub const IP_DROP_MEMBERSHIP: SockOpt = 13;
+    pub const IP_MULTICAST_TTL: c_int = 10;
+    pub const IP_MULTICAST_LOOP: c_int = 11;
+    pub const IP_ADD_MEMBERSHIP: c_int = 12;
+    pub const IP_DROP_MEMBERSHIP: c_int = 13;
 
     pub type InAddrT = u32;
 
diff --git a/src/sys/socket/mod.rs b/src/sys/socket/mod.rs
index 7e8afbfd..046df007 100644
--- a/src/sys/socket/mod.rs
+++ b/src/sys/socket/mod.rs
@@ -10,6 +10,7 @@ use std::os::unix::prelude::*;
 mod addr;
 mod consts;
 mod ffi;
+pub mod sockopt;
 
 /*
  *
@@ -264,34 +265,62 @@ pub struct linger {
     pub l_linger: c_int
 }
 
-pub fn getsockopt<T>(fd: Fd, level: SockLevel, opt: SockOpt, val: &mut T) -> NixResult<usize> {
-    let mut len = mem::size_of::<T>() as socklen_t;
+/*
+ *
+ * ===== Socket Options =====
+ *
+ */
 
-    let res = unsafe {
-        ffi::getsockopt(
-            fd, level, opt,
-            mem::transmute(val),
-            &mut len as *mut socklen_t)
-    };
+/// Represents a socket option that can be accessed or set
+pub trait SockOpt : Copy + fmt::Debug {
+    /// Type of `getsockopt` return value
+    type Get;
 
-    if res < 0 {
-        return Err(NixError::Sys(Errno::last()));
-    }
+    /// Type of value used to set the socket option. Used as the argument to
+    /// `setsockopt`.
+    type Set;
 
-    Ok(len as usize)
+    #[doc(hidden)]
+    fn get(&self, fd: Fd, level: c_int) -> NixResult<Self::Get>;
+
+    #[doc(hidden)]
+    fn set(&self, fd: Fd, level: c_int, val: Self::Set) -> NixResult<()>;
 }
 
-pub fn setsockopt<T>(fd: Fd, level: SockLevel, opt: SockOpt, val: &T) -> NixResult<()> {
-    let len = mem::size_of::<T>() as socklen_t;
+pub enum SockLevel {
+    Socket,
+    Tcp,
+    Ip,
+    Ipv6,
+    Udp
+}
 
-    let res = unsafe {
-            ffi::setsockopt(
-            fd, level, opt,
-            mem::transmute(val),
-            len)
-    };
+impl SockLevel {
+    fn as_cint(&self) -> c_int {
+        use self::SockLevel::*;
 
-    from_ffi(res)
+        match *self {
+            Socket => consts::SOL_SOCKET,
+            Tcp    => consts::IPPROTO_TCP,
+            Ip     => consts::IPPROTO_IP,
+            Ipv6   => consts::IPPROTO_IPV6,
+            Udp    => consts::IPPROTO_UDP,
+        }
+    }
+}
+
+/// Get the current value for the requested socket option
+///
+/// [Further reading](http://man7.org/linux/man-pages/man2/setsockopt.2.html)
+pub fn getsockopt<O: SockOpt>(fd: Fd, level: SockLevel, opt: O) -> NixResult<O::Get> {
+    opt.get(fd, level.as_cint())
+}
+
+/// Sets the value for the requested socket option
+///
+/// [Further reading](http://man7.org/linux/man-pages/man2/setsockopt.2.html)
+pub fn setsockopt<O: SockOpt>(fd: Fd, level: SockLevel, opt: O, val: O::Set) -> NixResult<()> {
+    opt.set(fd, level.as_cint(), val)
 }
 
 fn getpeername_sockaddr<T>(sockfd: Fd, addr: &T) -> NixResult<bool> {
diff --git a/src/sys/socket/sockopt.rs b/src/sys/socket/sockopt.rs
new file mode 100644
index 00000000..79c1800e
--- /dev/null
+++ b/src/sys/socket/sockopt.rs
@@ -0,0 +1,220 @@
+use {NixResult, NixError, from_ffi};
+use super::{ffi, consts, SockOpt};
+use errno::Errno;
+use libc::{c_int, uint8_t, c_void, socklen_t};
+use std::mem;
+use std::os::unix::Fd;
+
+// Helper to generate the sockopt accessors
+// TODO: Figure out how to ommit gets when not supported by opt
+macro_rules! sockopt_impl {
+    ($name:ident, $flag:path, bool) => {
+        sockopt_impl!($name, $flag, bool, GetBool, bool, SetBool);
+    };
+
+    ($name:ident, $flag:path, u8) => {
+        sockopt_impl!($name, $flag, u8, GetU8, u8, SetU8);
+    };
+
+    ($name:ident, $flag:path, $ty:ty) => {
+        sockopt_impl!($name, $flag, $ty, GetStruct<$ty>, &'a $ty, SetStruct<$ty>);
+    };
+
+    ($name:ident, $flag:path, $get_ty:ty, $getter:ty, $set_ty:ty, $setter:ty) => {
+        #[derive(Copy, Debug)]
+        pub struct $name;
+
+        impl<'a> SockOpt for $name {
+            type Get = $get_ty;
+            type Set = $set_ty;
+
+            fn get(&self, fd: Fd, level: c_int) -> NixResult<$get_ty> {
+                unsafe {
+                    let mut getter: $getter = Get::blank();
+
+                    let res = ffi::getsockopt(
+                        fd, level, $flag,
+                        getter.ffi_ptr(),
+                        getter.ffi_len());
+
+                    if res < 0 {
+                        return Err(NixError::Sys(Errno::last()));
+                    }
+
+                    Ok(getter.unwrap())
+                }
+            }
+
+            fn set(&self, fd: Fd, level: c_int, val: $set_ty) -> NixResult<()> {
+                unsafe {
+                    let setter: $setter = Set::new(val);
+
+                    let res = ffi::setsockopt(
+                        fd, level, $flag,
+                        setter.ffi_ptr(),
+                        setter.ffi_len());
+
+                    from_ffi(res)
+                }
+            }
+        }
+    };
+}
+
+/*
+ *
+ * ===== Define sockopts =====
+ *
+ */
+
+sockopt_impl!(ReuseAddr, consts::SO_REUSEADDR, bool);
+sockopt_impl!(ReusePort, consts::SO_REUSEPORT, bool);
+sockopt_impl!(TcpNoDelay, consts::TCP_NODELAY, bool);
+sockopt_impl!(Linger, consts::SO_LINGER, super::linger);
+sockopt_impl!(IpAddMembership, consts::IP_ADD_MEMBERSHIP, super::ip_mreq);
+sockopt_impl!(IpMulticastTtl, consts::IP_MULTICAST_TTL, u8);
+
+/*
+ *
+ * ===== Accessor helpers =====
+ *
+ */
+
+trait Get<T> {
+    unsafe fn blank() -> Self;
+    unsafe fn ffi_ptr(&mut self) -> *mut c_void;
+    unsafe fn ffi_len(&mut self) -> *mut socklen_t;
+    unsafe fn unwrap(self) -> T;
+}
+
+trait Set<T> {
+    fn new(val: T) -> Self;
+    unsafe fn ffi_ptr(&self) -> *const c_void;
+    unsafe fn ffi_len(&self) -> socklen_t;
+}
+
+struct GetStruct<T> {
+    len: socklen_t,
+    val: T,
+}
+
+impl<T> Get<T> for GetStruct<T> {
+    unsafe fn blank() -> Self {
+        mem::zeroed()
+    }
+
+    unsafe fn ffi_ptr(&mut self) -> *mut c_void {
+        mem::transmute(&mut self.val)
+    }
+
+    unsafe fn ffi_len(&mut self) -> *mut socklen_t {
+        mem::transmute(&mut self.len)
+    }
+
+    unsafe fn unwrap(self) -> T {
+        assert!(self.len as usize == mem::size_of::<T>(), "invalid getsockopt implementation");
+        self.val
+    }
+}
+
+struct SetStruct<'a, T: 'static> {
+    ptr: &'a T,
+}
+
+impl<'a, T> Set<&'a T> for SetStruct<'a, T> {
+    fn new(ptr: &'a T) -> SetStruct<'a, T> {
+        SetStruct { ptr: ptr }
+    }
+
+    unsafe fn ffi_ptr(&self) -> *const c_void {
+        mem::transmute(self.ptr)
+    }
+
+    unsafe fn ffi_len(&self) -> socklen_t {
+        mem::size_of::<T>() as socklen_t
+    }
+}
+
+struct GetBool {
+    len: socklen_t,
+    val: c_int,
+}
+
+impl Get<bool> for GetBool {
+    unsafe fn blank() -> Self {
+        mem::zeroed()
+    }
+
+    unsafe fn ffi_ptr(&mut self) -> *mut c_void {
+        mem::transmute(&mut self.val)
+    }
+
+    unsafe fn ffi_len(&mut self) -> *mut socklen_t {
+        mem::transmute(&mut self.len)
+    }
+
+    unsafe fn unwrap(self) -> bool {
+        assert!(self.len as usize == mem::size_of::<c_int>(), "invalid getsockopt implementation");
+        self.val != 0
+    }
+}
+
+struct SetBool {
+    val: c_int,
+}
+
+impl Set<bool> for SetBool {
+    fn new(val: bool) -> SetBool {
+        SetBool { val: if val { 1 } else { 0 } }
+    }
+
+    unsafe fn ffi_ptr(&self) -> *const c_void {
+        mem::transmute(&self.val)
+    }
+
+    unsafe fn ffi_len(&self) -> socklen_t {
+        mem::size_of::<c_int>() as socklen_t
+    }
+}
+
+struct GetU8 {
+    len: socklen_t,
+    val: uint8_t,
+}
+
+impl Get<u8> for GetU8 {
+    unsafe fn blank() -> Self {
+        mem::zeroed()
+    }
+
+    unsafe fn ffi_ptr(&mut self) -> *mut c_void {
+        mem::transmute(&mut self.val)
+    }
+
+    unsafe fn ffi_len(&mut self) -> *mut socklen_t {
+        mem::transmute(&mut self.len)
+    }
+
+    unsafe fn unwrap(self) -> u8 {
+        assert!(self.len as usize == mem::size_of::<uint8_t>(), "invalid getsockopt implementation");
+        self.val as u8
+    }
+}
+
+struct SetU8 {
+    val: uint8_t,
+}
+
+impl Set<u8> for SetU8 {
+    fn new(val: u8) -> SetU8 {
+        SetU8 { val: val as uint8_t }
+    }
+
+    unsafe fn ffi_ptr(&self) -> *const c_void {
+        mem::transmute(&self.val)
+    }
+
+    unsafe fn ffi_len(&self) -> socklen_t {
+        mem::size_of::<c_int>() as socklen_t
+    }
+}