[libos] Re-implement unix/host socket and unify net-related structs

src/libos/src/fs/events.rs

@@ -14,6 +14,9 @@ bitflags! {
         const HUP   = 0x0010; // = POLLHUP
         const NVAL  = 0x0020; // = POLLNVAL
         const RDHUP = 0x2000; // = POLLRDHUP
+
+        /// Events that are always polled even without specifying them.
+        const ALWAYS_POLL = Self::ERR.bits | Self::HUP.bits;
     }
 }
 

src/libos/src/fs/file_ops/file_flags.rs

@@ -129,4 +129,8 @@ impl StatusFlags {
     pub fn is_fast_open(&self) -> bool {
         self.contains(StatusFlags::O_PATH)
     }
+
+    pub fn is_nonblocking(&self) -> bool {
+        self.contains(StatusFlags::O_NONBLOCK)
+    }
 }

src/libos/src/fs/file_ops/ioctl/builtin/get_ifconf.rs

@@ -99,7 +99,7 @@ fn get_ifconf_by_host(fd: FileDesc, if_conf: &mut IfConf) -> Result<()> {
         // len: the size of the buf
         // recv_len: accepts transferred data length when buf is used to get data from host
         //
-        fn socket_ocall_ioctl_repack(
+        fn occlum_ocall_ioctl_repack(
             ret: *mut i32,
             fd: i32,
             cmd_num: i32,
@@ -112,7 +112,7 @@ fn get_ifconf_by_host(fd: FileDesc, if_conf: &mut IfConf) -> Result<()> {
     try_libc!({
         let mut recv_len: i32 = 0;
         let mut retval: i32 = 0;
-        let status = socket_ocall_ioctl_repack(
+        let status = occlum_ocall_ioctl_repack(
             &mut retval as *mut i32,
             fd as _,
             SIOCGIFCONF as _,

src/libos/src/net/io_multiplexing/poll_new/event_monitor.rs

@@ -1,10 +1,9 @@
-use std::cell::Cell;
 use std::ptr;
 use std::sync::Weak;
 use std::time::Duration;
 
 use crate::events::{Observer, Waiter, WaiterQueueObserver};
-use crate::fs::{AtomicIoEvents, IoEvents};
+use crate::fs::IoEvents;
 use crate::prelude::*;
 use crate::time::{timespec_t, TIMERSLACK};
 
@@ -265,13 +264,13 @@ trait ObserverExt {
 impl ObserverExt for Weak<dyn Observer<IoEvents>> {
     fn register_files<'a>(&self, files_and_events: impl Iterator<Item = &'a (FileRef, IoEvents)>) {
         for (file, events) in files_and_events {
-            let notifier = match file.notifier() {
+            match file.notifier() {
                 None => continue,
-                Some(notifier) => notifier,
+                Some(notifier) => {
+                    let mask = *events;
+                    notifier.register(self.clone(), Some(mask), None);
+                }
             };
-
-            let mask = *events;
-            notifier.register(self.clone(), Some(mask), None);
         }
     }
 
@@ -280,11 +279,12 @@ impl ObserverExt for Weak<dyn Observer<IoEvents>> {
         files_and_events: impl Iterator<Item = &'a (FileRef, IoEvents)>,
     ) {
         for (file, events) in files_and_events {
-            let notifier = match file.notifier() {
+            match file.notifier() {
                 None => continue,
-                Some(notifier) => notifier,
+                Some(notifier) => {
+                    notifier.unregister(self);
+                }
             };
-            notifier.unregister(self);
         }
     }
 }

src/libos/src/net/socket/flags.rs

@@ -1,43 +0,0 @@
-use super::*;
-
-bitflags! {
-    pub struct SendFlags: i32 {
-        const MSG_OOB          = 0x01;
-        const MSG_DONTROUTE    = 0x04;
-        const MSG_DONTWAIT     = 0x40;       // Nonblocking io
-        const MSG_EOR          = 0x80;       // End of record
-        const MSG_CONFIRM      = 0x0800;     // Confirm path validity
-        const MSG_NOSIGNAL     = 0x4000;     // Do not generate SIGPIPE
-        const MSG_MORE         = 0x8000;     // Sender will send more
-    }
-}
-
-bitflags! {
-    pub struct RecvFlags: i32 {
-        const MSG_OOB          = 0x01;
-        const MSG_PEEK         = 0x02;
-        const MSG_TRUNC        = 0x20;
-        const MSG_DONTWAIT     = 0x40;       // Nonblocking io
-        const MSG_WAITALL      = 0x0100;     // Wait for a full request
-        const MSG_ERRQUEUE     = 0x2000;     // Fetch message from error queue
-        const MSG_CMSG_CLOEXEC = 0x40000000; // Set close_on_exec for file descriptor received through M_RIGHTS
-    }
-}
-
-bitflags! {
-    pub struct MsgHdrFlags: i32 {
-        const MSG_OOB          = 0x01;
-        const MSG_CTRUNC       = 0x08;
-        const MSG_TRUNC        = 0x20;
-        const MSG_EOR          = 0x80;       // End of record
-        const MSG_ERRQUEUE     = 0x2000;     // Fetch message from error queue
-        const MSG_NOTIFICATION = 0x8000;     // Only applicable to SCTP socket
-    }
-}
-
-bitflags! {
-    pub struct FileFlags: i32 {
-        const SOCK_NONBLOCK = 0x800;
-        const SOCK_CLOEXEC  = 0x80000;
-    }
-}

src/libos/src/net/socket/host/ioctl_impl.rs

@@ -1,82 +0,0 @@
-use super::*;
-use fs::{occlum_ocall_ioctl, BuiltinIoctlNum, IfConf, IoctlCmd};
-
-impl HostSocket {
-    pub(super) fn ioctl_impl(&self, cmd: &mut IoctlCmd) -> Result<i32> {
-        if let IoctlCmd::SIOCGIFCONF(arg_ref) = cmd {
-            return self.ioctl_getifconf(arg_ref);
-        }
-
-        let cmd_num = cmd.cmd_num() as c_int;
-        let cmd_arg_ptr = cmd.arg_ptr() as *mut c_void;
-        let ret = try_libc!({
-            let mut retval: i32 = 0;
-            let status = occlum_ocall_ioctl(
-                &mut retval as *mut i32,
-                self.raw_host_fd() as i32,
-                cmd_num,
-                cmd_arg_ptr,
-                cmd.arg_len(),
-            );
-            assert!(status == sgx_status_t::SGX_SUCCESS);
-            retval
-        });
-        // FIXME: add sanity checks for results returned for socket-related ioctls
-        cmd.validate_arg_and_ret_vals(ret)?;
-        Ok(ret)
-    }
-
-    fn ioctl_getifconf(&self, arg_ref: &mut IfConf) -> Result<i32> {
-        if !arg_ref.ifc_buf.is_null() && arg_ref.ifc_len == 0 {
-            return Ok(0);
-        }
-
-        let ret = try_libc!({
-            let mut recv_len: i32 = 0;
-            let mut retval: i32 = 0;
-            let status = occlum_ocall_ioctl_repack(
-                &mut retval as *mut i32,
-                self.raw_host_fd() as i32,
-                BuiltinIoctlNum::SIOCGIFCONF as i32,
-                arg_ref.ifc_buf,
-                arg_ref.ifc_len,
-                &mut recv_len as *mut i32,
-            );
-            assert!(status == sgx_status_t::SGX_SUCCESS);
-            // If ifc_req is NULL, SIOCGIFCONF returns the necessary buffer
-            // size in bytes for receiving all available addresses in ifc_len
-            // which is irrelevant to the orginal ifc_len.
-            if !arg_ref.ifc_buf.is_null() {
-                assert!(arg_ref.ifc_len >= recv_len);
-            }
-
-            arg_ref.ifc_len = recv_len;
-            retval
-        });
-        Ok(ret)
-    }
-}
-
-extern "C" {
-    // Used to ioctl arguments with pointer members.
-    //
-    // Before the call the area the pointers points to should be assembled into
-    // one continous memory block. Then the block is repacked to ioctl arguments
-    // in the ocall implementation in host.
-    //
-    // ret: holds the return value of ioctl in host
-    // fd: the host fd for the device
-    // cmd_num: request number of the ioctl
-    // buf: the data to exchange with host
-    // len: the size of the buf
-    // recv_len: accepts transferred data length when buf is used to get data from host
-    //
-    fn occlum_ocall_ioctl_repack(
-        ret: *mut i32,
-        fd: c_int,
-        cmd_num: c_int,
-        buf: *const u8,
-        len: i32,
-        recv_len: *mut i32,
-    ) -> sgx_status_t;
-}

src/libos/src/net/socket/host/mod.rs

@@ -1,18 +1,16 @@
 use std::any::Any;
 use std::io::{Read, Seek, SeekFrom, Write};
 use std::mem;
-
 use atomic::Atomic;
 
 use super::*;
 use crate::fs::{
     occlum_ocall_ioctl, AccessMode, CreationFlags, File, FileRef, HostFd, IoEvents, IoNotifier,
-    IoctlCmd, StatusFlags,
+    IoctlRawCmd, StatusFlags,
 };
 
 use crate::process::IO_BUF_SIZE;
 
-mod ioctl_impl;
 mod recv;
 mod send;
 mod socket_file;
@@ -27,14 +25,14 @@ pub struct HostSocket {
 
 impl HostSocket {
     pub fn new(
-        domain: AddressFamily,
+        domain: Domain,
-        socket_type: SocketType,
+        socket_type: Type,
-        file_flags: FileFlags,
+        socket_flags: SocketFlags,
         protocol: i32,
     ) -> Result<Self> {
         let raw_host_fd = try_libc!(libc::ocall::socket(
             domain as i32,
-            socket_type as i32 | file_flags.bits(),
+            socket_type as i32 | socket_flags.bits(),
             protocol
         )) as FileDesc;
         let host_fd = HostFd::new(raw_host_fd);
@@ -51,7 +49,7 @@ impl HostSocket {
         })
     }
 
-    pub fn bind(&self, addr: &SockAddr) -> Result<()> {
+    pub fn bind(&self, addr: &RawAddr) -> Result<()> {
         let (addr_ptr, addr_len) = addr.as_ptr_and_len();
 
         let ret = try_libc!(libc::ocall::bind(
@@ -67,8 +65,8 @@ impl HostSocket {
         Ok(())
     }
 
-    pub fn accept(&self, flags: FileFlags) -> Result<(Self, Option<SockAddr>)> {
+    pub fn accept(&self, flags: SocketFlags) -> Result<(Self, Option<RawAddr>)> {
-        let mut sockaddr = SockAddr::default();
+        let mut sockaddr = RawAddr::default();
         let mut addr_len = sockaddr.len();
 
         let raw_host_fd = try_libc!(libc::ocall::accept4(
@@ -88,7 +86,33 @@ impl HostSocket {
         Ok((HostSocket::from_host_fd(host_fd)?, addr_option))
     }
 
-    pub fn connect(&self, addr: &Option<SockAddr>) -> Result<()> {
+    pub fn addr(&self) -> Result<RawAddr> {
+        let mut sockaddr = RawAddr::default();
+        let mut addr_len = sockaddr.len();
+        try_libc!(libc::ocall::getsockname(
+            self.raw_host_fd() as i32,
+            sockaddr.as_mut_ptr() as *mut _,
+            &mut addr_len as *mut _ as *mut _,
+        ));
+
+        sockaddr.set_len(addr_len)?;
+        Ok(sockaddr)
+    }
+
+    pub fn peer_addr(&self) -> Result<RawAddr> {
+        let mut sockaddr = RawAddr::default();
+        let mut addr_len = sockaddr.len();
+        try_libc!(libc::ocall::getpeername(
+            self.raw_host_fd() as i32,
+            sockaddr.as_mut_ptr() as *mut _,
+            &mut addr_len as *mut _ as *mut _,
+        ));
+
+        sockaddr.set_len(addr_len)?;
+        Ok(sockaddr)
+    }
+
+    pub fn connect(&self, addr: &Option<RawAddr>) -> Result<()> {
         debug!("connect: host_fd: {}, addr {:?}", self.raw_host_fd(), addr);
 
         let (addr_ptr, addr_len) = if let Some(sock_addr) = addr {
@@ -109,34 +133,29 @@ impl HostSocket {
         &self,
         buf: &[u8],
         flags: SendFlags,
-        addr_option: &Option<SockAddr>,
+        addr_option: &Option<RawAddr>,
     ) -> Result<usize> {
         let bufs = vec![buf];
-        let name_option = addr_option.as_ref().map(|addr| addr.as_slice());
+        self.sendmsg(&bufs, flags, addr_option, None)
-        self.do_sendmsg(&bufs, flags, name_option, None)
     }
 
-    pub fn recvfrom(&self, buf: &mut [u8], flags: RecvFlags) -> Result<(usize, Option<SockAddr>)> {
+    pub fn recvfrom(&self, buf: &mut [u8], flags: RecvFlags) -> Result<(usize, Option<RawAddr>)> {
-        let mut sockaddr = SockAddr::default();
+        let mut sockaddr = RawAddr::default();
         let mut bufs = vec![buf];
-        let (bytes_recv, addr_len, _, _) =
+        let (bytes_recv, recv_addr, _, _) = self.recvmsg(&mut bufs, flags, None)?;
-            self.do_recvmsg(&mut bufs, flags, Some(sockaddr.as_mut_slice()), None)?;
 
-        let addr_option = if addr_len != 0 {
+        Ok((bytes_recv, recv_addr))
-            sockaddr.set_len(addr_len)?;
-            Some(sockaddr)
-        } else {
-            None
-        };
-        Ok((bytes_recv, addr_option))
     }
 
     pub fn raw_host_fd(&self) -> FileDesc {
         self.host_fd.to_raw()
     }
 
-    pub fn shutdown(&self, how: HowToShut) -> Result<()> {
+    pub fn shutdown(&self, how: Shutdown) -> Result<()> {
-        try_libc!(libc::ocall::shutdown(self.raw_host_fd() as i32, how.bits()));
+        try_libc!(libc::ocall::shutdown(
+            self.raw_host_fd() as i32,
+            how.to_c() as i32
+        ));
         Ok(())
     }
 }

src/libos/src/net/socket/host/recv.rs

@@ -7,30 +7,12 @@ impl HostSocket {
         Ok(bytes_recvd)
     }
 
-    pub fn recvmsg<'a, 'b>(&self, msg: &'b mut MsgHdrMut<'a>, flags: RecvFlags) -> Result<usize> {
+    pub fn recvmsg(
-        // Do OCall-based recvmsg
-        let (bytes_recvd, namelen_recvd, controllen_recvd, flags_recvd) = {
-            // Acquire mutable references to the name and control buffers
-            let (iovs, name, control) = msg.get_iovs_name_and_control_mut();
-            // Fill the data, the name, and the control buffers
-            self.do_recvmsg(iovs.as_slices_mut(), flags, name, control)?
-        };
-
-        // Update the output lengths and flags
-        msg.set_name_len(namelen_recvd)?;
-        msg.set_control_len(controllen_recvd)?;
-        msg.set_flags(flags_recvd);
-
-        Ok(bytes_recvd)
-    }
-
-    pub(super) fn do_recvmsg(
         &self,
         data: &mut [&mut [u8]],
         flags: RecvFlags,
-        mut name: Option<&mut [u8]>,
+        control: Option<&mut [u8]>,
-        mut control: Option<&mut [u8]>,
+    ) -> Result<(usize, Option<RawAddr>, MsgFlags, usize)> {
-    ) -> Result<(usize, usize, usize, MsgHdrFlags)> {
         let current = current!();
         let data_length = data.iter().map(|s| s.len()).sum();
         let mut ocall_alloc;
@@ -52,7 +34,7 @@ impl HostSocket {
             }
             bufs
         };
-        let retval = self.do_recvmsg_untrusted_data(&mut u_data, flags, name, control)?;
+        let retval = self.do_recvmsg_untrusted_data(&mut u_data, flags, control)?;
 
         let mut remain = retval.0;
         for (i, buf) in data.iter_mut().enumerate() {
@@ -71,16 +53,15 @@ impl HostSocket {
         &self,
         data: &mut [UntrustedSlice],
         flags: RecvFlags,
-        mut name: Option<&mut [u8]>,
         mut control: Option<&mut [u8]>,
-    ) -> Result<(usize, usize, usize, MsgHdrFlags)> {
+    ) -> Result<(usize, Option<RawAddr>, MsgFlags, usize)> {
         // Prepare the arguments for OCall
-        // Host socket fd
         let host_fd = self.raw_host_fd() as i32;
-        // Name
+        let mut addr = RawAddr::default();
-        let (msg_name, msg_namelen) = name.as_mut_ptr_and_len();
+        let mut msg_name = addr.as_mut_ptr();
-        let msg_name = msg_name as *mut c_void;
+        let mut msg_namelen = addr.len();
         let mut msg_namelen_recvd = 0_u32;
+
         // Iovs
         let mut raw_iovs: Vec<libc::iovec> = data
             .iter()
@@ -101,7 +82,7 @@ impl HostSocket {
             let status = occlum_ocall_recvmsg(
                 &mut retval as *mut isize,
                 host_fd,
-                msg_name,
+                msg_name as _,
                 msg_namelen as u32,
                 &mut msg_namelen_recvd as *mut u32,
                 msg_iov,
@@ -119,7 +100,7 @@ impl HostSocket {
             retval
         });
 
-        let flags_recvd = MsgHdrFlags::from_bits(msg_flags_recvd).unwrap();
+        let flags_recvd = MsgFlags::from_bits(msg_flags_recvd).unwrap();
 
         // Check values returned from outside the enclave
         let bytes_recvd = {
@@ -133,21 +114,24 @@ impl HostSocket {
             // For MSG_TRUNC recvmsg returns the real length of the packet or datagram,
             // even when it was longer than the passed buffer.
             if flags.contains(RecvFlags::MSG_TRUNC) && retval > max_bytes_recvd {
-                assert!(flags_recvd.contains(MsgHdrFlags::MSG_TRUNC));
+                assert!(flags_recvd.contains(MsgFlags::MSG_TRUNC));
             } else {
                 assert!(retval <= max_bytes_recvd);
             }
             retval
         };
         let msg_namelen_recvd = msg_namelen_recvd as usize;
+
+        let raw_addr = if msg_namelen_recvd == 0 {
+            None
+        } else {
+            addr.set_len(msg_namelen_recvd)?;
+            Some(addr)
+        };
+
         assert!(msg_namelen_recvd <= msg_namelen);
         assert!(msg_controllen_recvd <= msg_controllen);
-        Ok((
+        Ok((bytes_recvd, raw_addr, flags_recvd, msg_controllen_recvd))
-            bytes_recvd,
-            msg_namelen_recvd,
-            msg_controllen_recvd,
-            flags_recvd,
-        ))
     }
 }
 

src/libos/src/net/socket/host/send.rs

@@ -5,22 +5,11 @@ impl HostSocket {
         self.sendto(buf, flags, &None)
     }
 
-    pub fn sendmsg<'a, 'b>(&self, msg: &'b MsgHdr<'a>, flags: SendFlags) -> Result<usize> {
+    pub fn sendmsg(
-        let msg_iov = msg.get_iovs();
-
-        self.do_sendmsg(
-            msg_iov.as_slices(),
-            flags,
-            msg.get_name(),
-            msg.get_control(),
-        )
-    }
-
-    pub(super) fn do_sendmsg(
         &self,
         data: &[&[u8]],
         flags: SendFlags,
-        name: Option<&[u8]>,
+        addr: &Option<RawAddr>,
         control: Option<&[u8]>,
     ) -> Result<usize> {
         let current = current!();
@@ -45,8 +34,8 @@ impl HostSocket {
             bufs
         };
 
-        let retval = self.do_sendmsg_untrusted_data(&u_data, flags, name, control);
+        let name = addr.as_ref().map(|raw_addr| raw_addr.as_slice());
-        retval
+        self.do_sendmsg_untrusted_data(&u_data, flags, name, control)
     }
 
     fn do_sendmsg_untrusted_data(

src/libos/src/net/socket/host/socket_file.rs

@@ -4,10 +4,11 @@ use std::io::{Read, Seek, SeekFrom, Write};
 use atomic::{Atomic, Ordering};
 
 use super::*;
+use crate::fs::{AccessMode, File, HostFd, IoEvents, StatusFlags, STATUS_FLAGS_MASK};
 use crate::fs::{
-    occlum_ocall_ioctl, AccessMode, AtomicIoEvents, CreationFlags, File, FileRef, HostFd, IoEvents,
+    GetIfConf, GetIfReqWithRawCmd, GetReadBufLen, IoctlCmd, NonBuiltinIoctlCmd, SetNonBlocking,
-    IoctlCmd, StatusFlags, STATUS_FLAGS_MASK,
 };
+use crate::net::socket::sockopt::{GetSockOptRawCmd, SetSockOptRawCmd};
 
 //TODO: refactor write syscall to allow zero length with non-zero buffer
 impl File for HostSocket {
@@ -34,20 +35,46 @@ impl File for HostSocket {
     }
 
     fn readv(&self, bufs: &mut [&mut [u8]]) -> Result<usize> {
-        let (bytes_recvd, _, _, _) = self.do_recvmsg(bufs, RecvFlags::empty(), None, None)?;
+        let (bytes_recvd, _, _, _) = self.recvmsg(bufs, RecvFlags::empty(), None)?;
         Ok(bytes_recvd)
     }
 
     fn writev(&self, bufs: &[&[u8]]) -> Result<usize> {
-        self.do_sendmsg(bufs, SendFlags::empty(), None, None)
+        self.sendmsg(bufs, SendFlags::empty(), &None, None)
     }
 
     fn seek(&self, pos: SeekFrom) -> Result<off_t> {
         return_errno!(ESPIPE, "Socket does not support seek")
     }
 
-    fn ioctl(&self, cmd: &mut IoctlCmd) -> Result<i32> {
+    fn ioctl(&self, cmd: &mut dyn IoctlCmd) -> Result<()> {
-        self.ioctl_impl(cmd)
+        match_ioctl_cmd_mut!(&mut *cmd, {
+            cmd: GetSockOptRawCmd => {
+                cmd.execute(self.raw_host_fd())?;
+            },
+            cmd: SetSockOptRawCmd => {
+                cmd.execute(self.raw_host_fd())?;
+            },
+            cmd: GetIfReqWithRawCmd => {
+                cmd.execute(self.raw_host_fd())?;
+            },
+            cmd: GetIfConf => {
+                cmd.execute(self.raw_host_fd())?;
+            },
+            cmd: GetReadBufLen => {
+                cmd.execute(self.raw_host_fd())?;
+            },
+            cmd: SetNonBlocking => {
+                cmd.execute(self.raw_host_fd())?;
+            },
+            cmd: NonBuiltinIoctlCmd => {
+                cmd.execute(self.raw_host_fd())?;
+            },
+            _ => {
+                return_errno!(EINVAL, "Not supported yet");
+            }
+        });
+        Ok(())
     }
 
     fn access_mode(&self) -> Result<AccessMode> {

src/libos/src/net/socket/msg.rs

@@ -1,354 +0,0 @@
-/// Socket message and its flags.
-use super::*;
-
-/// C struct for a socket message with const pointers
-#[repr(C)]
-#[derive(Debug, Copy, Clone)]
-pub struct msghdr {
-    pub msg_name: *const c_void,
-    pub msg_namelen: libc::socklen_t,
-    pub msg_iov: *const libc::iovec,
-    pub msg_iovlen: size_t,
-    pub msg_control: *const c_void,
-    pub msg_controllen: size_t,
-    pub msg_flags: c_int,
-}
-
-#[repr(C)]
-#[derive(Debug, Copy, Clone)]
-pub struct mmsghdr {
-    pub msg_hdr: msghdr,
-    pub msg_len: c_uint,
-}
-
-/// C struct for a socket message with mutable pointers
-#[repr(C)]
-#[derive(Debug, Copy, Clone)]
-pub struct msghdr_mut {
-    pub msg_name: *mut c_void,
-    pub msg_namelen: libc::socklen_t,
-    pub msg_iov: *mut libc::iovec,
-    pub msg_iovlen: size_t,
-    pub msg_control: *mut c_void,
-    pub msg_controllen: size_t,
-    pub msg_flags: c_int,
-}
-
-/// MsgHdr is a memory-safe, immutable wrapper of msghdr
-pub struct MsgHdr<'a> {
-    name: Option<&'a [u8]>,
-    iovs: Iovs<'a>,
-    control: Option<&'a [u8]>,
-    flags: MsgHdrFlags,
-    c_self: &'a msghdr,
-}
-
-impl<'a> MsgHdr<'a> {
-    /// Wrap a unsafe msghdr into a safe MsgHdr
-    pub unsafe fn from_c(c_msg: &'a msghdr) -> Result<MsgHdr> {
-        // Convert c_msg's (*mut T, usize)-pair fields to Option<&mut [T]>
-        let name_opt_slice =
-            new_optional_slice(c_msg.msg_name as *const u8, c_msg.msg_namelen as usize);
-        let iovs_opt_slice = new_optional_slice(
-            c_msg.msg_iov as *const libc::iovec,
-            c_msg.msg_iovlen as usize,
-        );
-        let control_opt_slice = new_optional_slice(
-            c_msg.msg_control as *const u8,
-            c_msg.msg_controllen as usize,
-        );
-
-        let flags = MsgHdrFlags::from_bits_truncate(c_msg.msg_flags);
-
-        let iovs = {
-            let iovs_vec = match iovs_opt_slice {
-                Some(iovs_slice) => iovs_slice
-                    .iter()
-                    .flat_map(|iov| new_optional_slice(iov.iov_base as *const u8, iov.iov_len))
-                    .collect(),
-                None => Vec::new(),
-            };
-            Iovs::new(iovs_vec)
-        };
-
-        Ok(Self {
-            name: name_opt_slice,
-            iovs: iovs,
-            control: control_opt_slice,
-            flags: flags,
-            c_self: c_msg,
-        })
-    }
-
-    pub fn get_iovs(&self) -> &Iovs {
-        &self.iovs
-    }
-
-    pub fn get_name(&self) -> Option<&[u8]> {
-        self.name
-    }
-
-    pub fn get_control(&self) -> Option<&[u8]> {
-        self.control
-    }
-
-    pub fn get_flags(&self) -> MsgHdrFlags {
-        self.flags
-    }
-}
-
-/// MsgHdrMut is a memory-safe, mutable wrapper of msghdr_mut
-pub struct MsgHdrMut<'a> {
-    name: Option<&'a mut [u8]>,
-    iovs: IovsMut<'a>,
-    control: Option<&'a mut [u8]>,
-    flags: MsgHdrFlags,
-    c_self: &'a mut msghdr_mut,
-}
-
-// TODO: use macros to eliminate redundant code between MsgHdr and MsgHdrMut
-impl<'a> MsgHdrMut<'a> {
-    /// Wrap a unsafe msghdr_mut into a safe MsgHdrMut
-    pub unsafe fn from_c(c_msg: &'a mut msghdr_mut) -> Result<MsgHdrMut> {
-        // Convert c_msg's (*mut T, usize)-pair fields to Option<&mut [T]>
-        let name_opt_slice =
-            new_optional_slice_mut(c_msg.msg_name as *mut u8, c_msg.msg_namelen as usize);
-        let iovs_opt_slice =
-            new_optional_slice_mut(c_msg.msg_iov as *mut libc::iovec, c_msg.msg_iovlen as usize);
-        let control_opt_slice =
-            new_optional_slice_mut(c_msg.msg_control as *mut u8, c_msg.msg_controllen as usize);
-
-        let flags = MsgHdrFlags::from_bits_truncate(c_msg.msg_flags);
-
-        let iovs = {
-            let iovs_vec = match iovs_opt_slice {
-                Some(iovs_slice) => iovs_slice
-                    .iter()
-                    .flat_map(|iov| new_optional_slice_mut(iov.iov_base as *mut u8, iov.iov_len))
-                    .collect(),
-                None => Vec::new(),
-            };
-            IovsMut::new(iovs_vec)
-        };
-
-        Ok(Self {
-            name: name_opt_slice,
-            iovs: iovs,
-            control: control_opt_slice,
-            flags: flags,
-            c_self: c_msg,
-        })
-    }
-
-    /////////////////////////////////////////////////////////////////////////
-    // Immutable interfaces (same as MsgHdr)
-    /////////////////////////////////////////////////////////////////////////
-
-    pub fn get_iovs(&self) -> &IovsMut {
-        &self.iovs
-    }
-
-    pub fn get_name(&self) -> Option<&[u8]> {
-        self.name.as_ref().map(|name| &name[..])
-    }
-
-    pub fn get_control(&self) -> Option<&[u8]> {
-        self.control.as_ref().map(|control| &control[..])
-    }
-
-    pub fn get_flags(&self) -> MsgHdrFlags {
-        self.flags
-    }
-
-    /////////////////////////////////////////////////////////////////////////
-    // Mutable interfaces (unique to MsgHdrMut)
-    /////////////////////////////////////////////////////////////////////////
-
-    pub fn get_iovs_mut<'b>(&'b mut self) -> &'b mut IovsMut<'a> {
-        &mut self.iovs
-    }
-
-    pub fn get_name_mut(&mut self) -> Option<&mut [u8]> {
-        self.name.as_mut().map(|name| &mut name[..])
-    }
-
-    pub fn get_name_max_len(&self) -> usize {
-        self.name.as_ref().map(|name| name.len()).unwrap_or(0)
-    }
-
-    pub fn set_name_len(&mut self, new_name_len: usize) -> Result<()> {
-        if new_name_len > self.get_name_max_len() {
-            return_errno!(EINVAL, "new_name_len is too big");
-        }
-        self.c_self.msg_namelen = new_name_len as libc::socklen_t;
-        Ok(())
-    }
-
-    pub fn get_control_mut(&mut self) -> Option<&mut [u8]> {
-        self.control.as_mut().map(|control| &mut control[..])
-    }
-
-    pub fn get_control_max_len(&self) -> usize {
-        self.control
-            .as_ref()
-            .map(|control| control.len())
-            .unwrap_or(0)
-    }
-
-    pub fn set_control_len(&mut self, new_control_len: usize) -> Result<()> {
-        if new_control_len > self.get_control_max_len() {
-            return_errno!(EINVAL, "new_control_len is too big");
-        }
-        self.c_self.msg_controllen = new_control_len;
-        Ok(())
-    }
-
-    pub fn get_iovs_name_and_control_mut(
-        &mut self,
-    ) -> (&mut IovsMut<'a>, Option<&mut [u8]>, Option<&mut [u8]>) {
-        (
-            &mut self.iovs,
-            self.name.as_mut().map(|name| &mut name[..]),
-            self.control.as_mut().map(|control| &mut control[..]),
-        )
-    }
-
-    pub fn set_flags(&mut self, flags: MsgHdrFlags) {
-        self.flags = flags;
-        self.c_self.msg_flags = flags.bits();
-    }
-}
-
-/// This struct is used to iterate through the control messages.
-///
-/// `cmsghdr` is a C struct for ancillary data object information of a unix socket.
-pub struct CMessages<'a> {
-    buffer: &'a [u8],
-    current: Option<&'a libc::cmsghdr>,
-}
-
-impl<'a> Iterator for CMessages<'a> {
-    type Item = CmsgData<'a>;
-
-    fn next(&mut self) -> Option<Self::Item> {
-        let cmsg = unsafe {
-            let mut msg: libc::msghdr = core::mem::zeroed();
-            msg.msg_control = self.buffer.as_ptr() as *mut _;
-            msg.msg_controllen = self.buffer.len() as _;
-
-            let cmsg = if let Some(current) = self.current {
-                libc::CMSG_NXTHDR(&msg, current)
-            } else {
-                libc::CMSG_FIRSTHDR(&msg)
-            };
-            cmsg.as_ref()?
-        };
-
-        self.current = Some(cmsg);
-        CmsgData::try_from_cmsghdr(cmsg)
-    }
-}
-
-impl<'a> CMessages<'a> {
-    pub fn from_bytes(msg_control: &'a mut [u8]) -> Self {
-        Self {
-            buffer: msg_control,
-            current: None,
-        }
-    }
-}
-
-/// Control message data of variable type. The data resides next to `cmsghdr`.
-pub enum CmsgData<'a> {
-    ScmRights(ScmRights<'a>),
-    ScmCredentials,
-}
-
-impl<'a> CmsgData<'a> {
-    /// Create an `CmsgData::ScmRights` variant.
-    ///
-    /// # Safety
-    ///
-    /// `data` must contain a valid control message and the control message must be type of
-    /// `SOL_SOCKET` and level of `SCM_RIGHTS`.
-    unsafe fn as_rights(data: &'a mut [u8]) -> Self {
-        let scm_rights = ScmRights { data };
-        CmsgData::ScmRights(scm_rights)
-    }
-
-    /// Create an `CmsgData::ScmCredentials` variant.
-    ///
-    /// # Safety
-    ///
-    /// `data` must contain a valid control message and the control message must be type of
-    /// `SOL_SOCKET` and level of `SCM_CREDENTIALS`.
-    unsafe fn as_credentials(_data: &'a [u8]) -> Self {
-        CmsgData::ScmCredentials
-    }
-
-    fn try_from_cmsghdr(cmsg: &'a libc::cmsghdr) -> Option<Self> {
-        unsafe {
-            let cmsg_len_zero = libc::CMSG_LEN(0) as usize;
-            let data_len = (*cmsg).cmsg_len as usize - cmsg_len_zero;
-            let data = libc::CMSG_DATA(cmsg);
-            let data = core::slice::from_raw_parts_mut(data, data_len);
-
-            match (*cmsg).cmsg_level {
-                libc::SOL_SOCKET => match (*cmsg).cmsg_type {
-                    libc::SCM_RIGHTS => Some(CmsgData::as_rights(data)),
-                    libc::SCM_CREDENTIALS => Some(CmsgData::as_credentials(data)),
-                    _ => None,
-                },
-                _ => None,
-            }
-        }
-    }
-}
-
-/// The data unit of this control message is file descriptor(s).
-///
-/// The level is equal to `SOL_SOCKET` and the type is equal to `SCM_RIGHTS`.
-pub struct ScmRights<'a> {
-    data: &'a mut [u8],
-}
-
-impl<'a> ScmRights<'a> {
-    /// Iterate and reassign each fd in data buffer, given a reassignment function.
-    pub fn iter_and_reassign_fds<F>(&mut self, reassign_fd_fn: F)
-    where
-        F: Fn(FileDesc) -> FileDesc,
-    {
-        for fd_bytes in self.data.chunks_exact_mut(core::mem::size_of::<FileDesc>()) {
-            let old_fd = FileDesc::from_ne_bytes(fd_bytes.try_into().unwrap());
-            let reassigned_fd = reassign_fd_fn(old_fd);
-            fd_bytes.copy_from_slice(&reassigned_fd.to_ne_bytes());
-        }
-    }
-
-    pub fn iter_fds(&self) -> impl Iterator<Item = FileDesc> + '_ {
-        self.data
-            .chunks_exact(core::mem::size_of::<FileDesc>())
-            .map(|fd_bytes| FileDesc::from_ne_bytes(fd_bytes.try_into().unwrap()))
-    }
-}
-
-unsafe fn new_optional_slice<'a, T>(slice_ptr: *const T, slice_size: usize) -> Option<&'a [T]> {
-    if !slice_ptr.is_null() {
-        let slice = core::slice::from_raw_parts::<T>(slice_ptr, slice_size);
-        Some(slice)
-    } else {
-        None
-    }
-}
-
-unsafe fn new_optional_slice_mut<'a, T>(
-    slice_ptr: *mut T,
-    slice_size: usize,
-) -> Option<&'a mut [T]> {
-    if !slice_ptr.is_null() {
-        let slice = core::slice::from_raw_parts_mut::<T>(slice_ptr, slice_size);
-        Some(slice)
-    } else {
-        None
-    }
-}

src/libos/src/net/socket/shutdown.rs

@@ -1,28 +0,0 @@
-use super::*;
-
-bitflags! {
-   pub struct HowToShut: c_int {
-        const READ = 0;
-        const WRITE = 1;
-        const BOTH = 2;
-   }
-}
-
-impl HowToShut {
-    pub fn try_from_raw(how: c_int) -> Result<Self> {
-        match how {
-            0 => Ok(Self::READ),
-            1 => Ok(Self::WRITE),
-            2 => Ok(Self::BOTH),
-            _ => return_errno!(EINVAL, "invalid how"),
-        }
-    }
-
-    pub fn to_shut_read(&self) -> bool {
-        *self == Self::READ || *self == Self::BOTH
-    }
-
-    pub fn to_shut_write(&self) -> bool {
-        *self == Self::WRITE || *self == Self::BOTH
-    }
-}

src/libos/src/net/socket/socket_type.rs

@@ -1,29 +0,0 @@
-use super::*;
-
-#[derive(Copy, Clone, Debug, PartialEq, Eq)]
-#[repr(i32)]
-#[allow(non_camel_case_types)]
-pub enum SocketType {
-    STREAM = 1,
-    DGRAM = 2,
-    RAW = 3,
-    RDM = 4,
-    SEQPACKET = 5,
-    DCCP = 6,
-    PACKET = 10,
-}
-
-impl SocketType {
-    pub fn try_from(sock_type: i32) -> Result<Self> {
-        match sock_type {
-            1 => Ok(SocketType::STREAM),
-            2 => Ok(SocketType::DGRAM),
-            3 => Ok(SocketType::RAW),
-            4 => Ok(SocketType::RDM),
-            5 => Ok(SocketType::SEQPACKET),
-            6 => Ok(SocketType::DCCP),
-            10 => Ok(SocketType::PACKET),
-            _ => return_errno!(EINVAL, "invalid socket type"),
-        }
-    }
-}

src/libos/src/net/socket/unix/addr.rs

@@ -1,156 +0,0 @@
-use super::*;
-use std::path::{Path, PathBuf};
-use std::{cmp, mem, slice, str};
-
-const MAX_PATH_LEN: usize = 108;
-const SUN_FAMILY_LEN: usize = mem::size_of::<libc::sa_family_t>();
-lazy_static! {
-    static ref SUN_PATH_OFFSET: usize = memoffset::offset_of!(libc::sockaddr_un, sun_path);
-}
-
-#[derive(Clone, Debug, Eq, PartialEq)]
-pub enum Addr {
-    File(Option<usize>, UnixPath), // An optional inode number and path. Use inode if there is one.
-    Abstract(String),
-}
-
-impl Addr {
-    /// Caller should guarentee the sockaddr and addr_len are valid.
-    /// The pathname should end with a '\0' within the passed length.
-    /// The abstract name should both start and end with a '\0' within the passed length.
-    pub unsafe fn try_from_raw(
-        sockaddr: *const libc::sockaddr,
-        addr_len: libc::socklen_t,
-    ) -> Result<Self> {
-        let addr_len = addr_len as usize;
-
-        // TODO: support autobind to validate when addr_len == SUN_FAMILY_LEN
-        if addr_len <= SUN_FAMILY_LEN {
-            return_errno!(EINVAL, "the address is too short.");
-        }
-
-        if addr_len > MAX_PATH_LEN + *SUN_PATH_OFFSET {
-            return_errno!(EINVAL, "the address is too long.");
-        }
-
-        if AddressFamily::try_from((*sockaddr).sa_family)? != AddressFamily::LOCAL {
-            return_errno!(EINVAL, "not a valid address for unix socket");
-        }
-
-        let sockaddr = sockaddr as *const libc::sockaddr_un;
-        let sun_path = (*sockaddr).sun_path;
-
-        if sun_path[0] == 0 {
-            let path_ptr = sun_path[1..(addr_len - *SUN_PATH_OFFSET)].as_ptr();
-            let path_slice =
-                slice::from_raw_parts(path_ptr as *const u8, addr_len - *SUN_PATH_OFFSET - 1);
-
-            Ok(Self::Abstract(
-                str::from_utf8(&path_slice).unwrap().to_string(),
-            ))
-        } else {
-            let path_cstr = CStr::from_ptr(sun_path.as_ptr());
-            if path_cstr.to_bytes_with_nul().len() > MAX_PATH_LEN {
-                return_errno!(EINVAL, "no null in the address");
-            }
-
-            Ok(Self::File(None, UnixPath::new(path_cstr.to_str().unwrap())))
-        }
-    }
-
-    pub fn copy_to_slice(&self, dst: &mut [u8]) -> usize {
-        let (raw_addr, addr_len) = self.to_raw();
-        let src =
-            unsafe { std::slice::from_raw_parts(&raw_addr as *const _ as *const u8, addr_len) };
-        let copied = std::cmp::min(dst.len(), addr_len);
-        dst[..copied].copy_from_slice(&src[..copied]);
-        copied
-    }
-
-    pub fn raw_len(&self) -> usize {
-        /// The '/0' at the end of Self::File counts
-        self.path_str().len()
-            + 1
-            + *SUN_PATH_OFFSET
-    }
-
-    pub fn path_str(&self) -> &str {
-        match self {
-            Self::File(_, unix_path) => &unix_path.path_str(),
-            Self::Abstract(path) => &path,
-        }
-    }
-
-    fn to_raw(&self) -> (libc::sockaddr_un, usize) {
-        let mut addr: libc::sockaddr_un = unsafe { mem::zeroed() };
-        addr.sun_family = AddressFamily::LOCAL as libc::sa_family_t;
-
-        let addr_len = match self {
-            Self::File(_, unix_path) => {
-                let path_str = unix_path.path_str();
-                let buf_len = path_str.len();
-                /// addr is initialized to all zeros and try_from_raw guarentees
-                /// unix_path length is shorter than sun_path, so sun_path here
-                /// will always have a null terminator
-                addr.sun_path[..buf_len]
-                    .copy_from_slice(unsafe { &*(path_str.as_bytes() as *const _ as *const [i8]) });
-                buf_len + *SUN_PATH_OFFSET + 1
-            }
-            Self::Abstract(path_str) => {
-                addr.sun_path[0] = 0;
-                let buf_len = path_str.len() + 1;
-                addr.sun_path[1..buf_len]
-                    .copy_from_slice(unsafe { &*(path_str.as_bytes() as *const _ as *const [i8]) });
-                buf_len + *SUN_PATH_OFFSET
-            }
-        };
-
-        (addr, addr_len)
-    }
-}
-
-#[derive(Clone, Debug, Eq, PartialEq)]
-pub struct UnixPath {
-    inner: PathBuf,
-    /// Holds the cwd when a relative path is created
-    cwd: Option<String>,
-}
-
-impl UnixPath {
-    pub fn new(path: &str) -> Self {
-        let inner = PathBuf::from(path);
-        let is_absolute = inner.is_absolute();
-        Self {
-            inner: inner,
-            cwd: if is_absolute {
-                None
-            } else {
-                let thread = current!();
-                let fs = thread.fs().read().unwrap();
-                let cwd = fs.cwd().to_owned();
-
-                Some(cwd)
-            },
-        }
-    }
-
-    pub fn absolute(&self) -> String {
-        let path_str = self.path_str();
-        if self.inner.is_absolute() {
-            path_str.to_string()
-        } else {
-            let mut prefix = self.cwd.as_ref().unwrap().clone();
-            if prefix.ends_with("/") {
-                prefix.push_str(path_str);
-            } else {
-                prefix.push_str("/");
-                prefix.push_str(path_str);
-            }
-            prefix
-        }
-    }
-
-    pub fn path_str(&self) -> &str {
-        self.inner.to_str().unwrap()
-    }
-}

src/libos/src/net/socket/unix/mod.rs

@@ -1,19 +1,16 @@
-use self::addr::Addr;
 use super::*;
 
-mod addr;
 mod stream;
 
-pub use self::addr::Addr as UnixAddr;
 pub use self::stream::Stream;
 
 //TODO: rewrite this file when a new kind of uds is added
-pub fn unix_socket(socket_type: SocketType, flags: FileFlags, protocol: i32) -> Result<Stream> {
+pub fn unix_socket(socket_type: Type, flags: SocketFlags, protocol: i32) -> Result<Stream> {
-    if protocol != 0 && protocol != AddressFamily::LOCAL as i32 {
+    if protocol != 0 && protocol != Domain::LOCAL as i32 {
         return_errno!(EPROTONOSUPPORT, "protocol is not supported");
     }
 
-    if socket_type == SocketType::STREAM {
+    if socket_type == Type::STREAM {
         Ok(Stream::new(flags))
     } else {
         return_errno!(ESOCKTNOSUPPORT, "only stream type is supported");
@@ -21,15 +18,15 @@ pub fn unix_socket(socket_type: SocketType, flags: FileFlags, protocol: i32) ->
 }
 
 pub fn socketpair(
-    socket_type: SocketType,
+    socket_type: Type,
-    flags: FileFlags,
+    flags: SocketFlags,
     protocol: i32,
 ) -> Result<(Stream, Stream)> {
-    if protocol != 0 && protocol != AddressFamily::LOCAL as i32 {
+    if protocol != 0 && protocol != Domain::LOCAL as i32 {
         return_errno!(EPROTONOSUPPORT, "protocol is not supported");
     }
 
-    if socket_type == SocketType::STREAM {
+    if socket_type == Type::STREAM {
         Stream::socketpair(flags)
     } else {
         return_errno!(ESOCKTNOSUPPORT, "only stream type is supported");

src/libos/src/net/socket/unix/stream/address_space.rs

@@ -39,9 +39,9 @@ impl AddressSpace {
         }
     }
 
-    pub fn add_binder(&self, addr: &Addr) -> Result<()> {
+    pub fn add_binder(&self, addr: &UnixAddr) -> Result<()> {
         let key = Self::get_key(addr).ok_or_else(|| errno!(EINVAL, "can't find socket file"))?;
-        let mut space = self.get_space(addr);
+        let mut space = self.get_space(addr)?;
         if space.contains_key(&key) {
             return_errno!(EADDRINUSE, "the addr is already bound");
         } else {
@@ -52,13 +52,13 @@ impl AddressSpace {
 
     pub(super) fn add_listener(
         &self,
-        addr: &Addr,
+        addr: &UnixAddr,
         capacity: usize,
         nonblocking: bool,
         notifier: Arc<RelayNotifier>,
     ) -> Result<()> {
         let key = Self::get_key(addr).ok_or_else(|| errno!(EINVAL, "the socket is not bound"))?;
-        let mut space = self.get_space(addr);
+        let mut space = self.get_space(addr)?;
 
         if let Some(option) = space.get(&key) {
             if option.is_none() {
@@ -75,9 +75,9 @@ impl AddressSpace {
         }
     }
 
-    pub fn resize_listener(&self, addr: &Addr, capacity: usize) -> Result<()> {
+    pub fn resize_listener(&self, addr: &UnixAddr, capacity: usize) -> Result<()> {
         let key = Self::get_key(addr).ok_or_else(|| errno!(EINVAL, "the socket is not bound"))?;
-        let mut space = self.get_space(addr);
+        let mut space = self.get_space(addr)?;
 
         if let Some(option) = space.get(&key) {
             if let Some(listener) = option {
@@ -91,33 +91,33 @@ impl AddressSpace {
         }
     }
 
-    pub fn push_incoming(&self, addr: &Addr, sock: Endpoint) -> Result<()> {
+    pub fn push_incoming(&self, addr: &UnixAddr, sock: Endpoint) -> Result<()> {
         self.get_listener_ref(addr)
             .ok_or_else(|| errno!(ECONNREFUSED, "no one's listening on the remote address"))?
             .push_incoming(sock)
     }
 
-    pub fn pop_incoming(&self, addr: &Addr) -> Result<Endpoint> {
+    pub fn pop_incoming(&self, addr: &UnixAddr) -> Result<Endpoint> {
         self.get_listener_ref(addr)
             .ok_or_else(|| errno!(EINVAL, "the socket is not listening"))?
             .pop_incoming()
             .ok_or_else(|| errno!(EAGAIN, "No connection is incoming"))
     }
 
-    pub fn get_listener_ref(&self, addr: &Addr) -> Option<Arc<Listener>> {
+    pub fn get_listener_ref(&self, addr: &UnixAddr) -> Option<Arc<Listener>> {
         let key = Self::get_key(addr);
         if let Some(key) = key {
-            let space = self.get_space(addr);
+            let space = self.get_space(addr).unwrap();
             space.get(&key).map(|x| x.clone()).flatten()
         } else {
             None
         }
     }
 
-    pub fn remove_addr(&self, addr: &Addr) {
+    pub fn remove_addr(&self, addr: &UnixAddr) {
         let key = Self::get_key(addr);
         if let Some(key) = key {
-            let mut space = self.get_space(addr);
+            let mut space = self.get_space(addr).unwrap();
             space.remove(&key);
         } else {
             warn!("address space key not exit: {:?}", addr);
@@ -126,21 +126,22 @@ impl AddressSpace {
 
     fn get_space(
         &self,
-        addr: &Addr,
+        addr: &UnixAddr,
-    ) -> SgxMutexGuard<'_, BTreeMap<AddressSpaceKey, Option<Arc<Listener>>>> {
+    ) -> Result<SgxMutexGuard<'_, BTreeMap<AddressSpaceKey, Option<Arc<Listener>>>>> {
         match addr {
-            Addr::File(_, _) => self.file.lock().unwrap(),
+            UnixAddr::File(_, _) => Ok(self.file.lock().unwrap()),
-            Addr::Abstract(_) => self.abstr.lock().unwrap(),
+            UnixAddr::Abstract(_) => Ok(self.abstr.lock().unwrap()),
+            UnixAddr::Unnamed => return_errno!(EINVAL, "can't get path name for unnamed socket"),
         }
     }
 
-    fn get_key(addr: &Addr) -> Option<AddressSpaceKey> {
+    fn get_key(addr: &UnixAddr) -> Option<AddressSpaceKey> {
         trace!("addr = {:?}", addr);
         match addr {
-            Addr::File(inode_num, unix_path) if inode_num.is_some() => {
+            UnixAddr::File(inode_num, unix_path) if inode_num.is_some() => {
                 Some(AddressSpaceKey::from_inode(inode_num.unwrap()))
             }
-            Addr::File(_, unix_path) => {
+            UnixAddr::File(_, unix_path) => {
                 let inode = {
                     let file_path = unix_path.absolute();
                     let current = current!();
@@ -153,7 +154,10 @@ impl AddressSpace {
                     None
                 }
             }
-            Addr::Abstract(path) => Some(AddressSpaceKey::from_path(addr.path_str().to_string())),
+            UnixAddr::Abstract(path) => Some(AddressSpaceKey::from_path(
+                addr.path_str().unwrap().to_string(),
+            )),
+            UnixAddr::Unnamed => None,
         }
     }
 }

src/libos/src/net/socket/unix/stream/endpoint.rs

@@ -39,7 +39,7 @@ pub fn end_pair(nonblocking: bool) -> Result<(Endpoint, Endpoint)> {
 
 /// One end of the connected unix socket
 pub struct Inner {
-    addr: RwLock<Option<Addr>>,
+    addr: RwLock<Option<UnixAddr>>,
     reader: Consumer<u8>,
     writer: Producer<u8>,
     peer: Weak<Self>,
@@ -47,15 +47,15 @@ pub struct Inner {
 }
 
 impl Inner {
-    pub fn addr(&self) -> Option<Addr> {
+    pub fn addr(&self) -> Option<UnixAddr> {
         self.addr.read().unwrap().clone()
     }
 
-    pub fn set_addr(&self, addr: &Addr) {
+    pub fn set_addr(&self, addr: &UnixAddr) {
         *self.addr.write().unwrap() = Some(addr.clone());
     }
 
-    pub fn peer_addr(&self) -> Option<Addr> {
+    pub fn peer_addr(&self) -> Option<UnixAddr> {
         self.peer.upgrade().map(|end| end.addr().clone()).flatten()
     }
 
@@ -90,16 +90,16 @@ impl Inner {
         self.reader.items_to_consume()
     }
 
-    pub fn shutdown(&self, how: HowToShut) -> Result<()> {
+    pub fn shutdown(&self, how: Shutdown) -> Result<()> {
         if !self.is_connected() {
             return_errno!(ENOTCONN, "The socket is not connected.");
         }
 
-        if how.to_shut_read() {
+        if how.should_shut_read() {
             self.reader.shutdown()
         }
 
-        if how.to_shut_write() {
+        if how.should_shut_write() {
             self.writer.shutdown()
         }
 

src/libos/src/net/socket/unix/stream/file.rs

@@ -1,10 +1,12 @@
 use super::address_space::ADDRESS_SPACE;
 use super::stream::Status;
 use super::*;
-use fs::{AccessMode, File, FileRef, IoEvents, IoNotifier, IoctlCmd, StatusFlags};
+use fs::{AccessMode, File, IoEvents, IoNotifier, StatusFlags};
 use rcore_fs::vfs::{FileType, Metadata, Timespec};
 use std::any::Any;
 
+use crate::fs::{GetReadBufLen, IoctlCmd, SetNonBlocking};
+
 impl File for Stream {
     fn read(&self, buf: &mut [u8]) -> Result<usize> {
         // The connected status will not be changed any more
@@ -55,23 +57,23 @@ impl File for Stream {
         }
     }
 
-    fn ioctl(&self, cmd: &mut IoctlCmd) -> Result<i32> {
+    fn ioctl(&self, cmd: &mut dyn IoctlCmd) -> Result<()> {
-        match cmd {
+        match_ioctl_cmd_auto_error!(cmd, {
-            IoctlCmd::TCGETS(_) => return_errno!(ENOTTY, "not tty device"),
+            cmd : GetReadBufLen => {
-            IoctlCmd::TCSETS(_) => return_errno!(ENOTTY, "not tty device"),
+                match &*self.inner() {
-            IoctlCmd::FIONBIO(nonblocking) => {
+                    Status::Connected(endpoint) => {
-                self.set_nonblocking(**nonblocking != 0);
+                        let bytes_to_read = endpoint.bytes_to_read().min(std::i32::MAX as usize) as i32;
-            }
+                        cmd.set_output(bytes_to_read as _);
-            IoctlCmd::FIONREAD(arg) => match &*self.inner() {
+                    }
-                Status::Connected(endpoint) => {
+                    _ => return_errno!(ENOTCONN, "unconnected socket"),
-                    let bytes_to_read = endpoint.bytes_to_read().min(std::i32::MAX as usize) as i32;
+                };
-                    **arg = bytes_to_read;
-                }
-                _ => return_errno!(ENOTCONN, "unconnected socket"),
             },
-            _ => return_errno!(EINVAL, "unknown ioctl cmd for unix socket"),
+            cmd : SetNonBlocking => {
-        }
+                let nonblocking = cmd.input();
-        Ok(0)
+                self.set_nonblocking(*nonblocking != 0);
+            }
+        });
+        Ok(())
     }
 
     fn access_mode(&self) -> Result<AccessMode> {

src/libos/src/net/socket/unix/stream/stream.rs

@@ -5,7 +5,7 @@ use events::{Event, EventFilter, Notifier, Observer};
 use fs::channel::Channel;
 use fs::IoEvents;
 use fs::{CreationFlags, FileMode};
-use net::socket::{CMessages, CmsgData, Iovs, MsgHdr, MsgHdrMut};
+use net::socket::{CMessages, CmsgData};
 use std::fmt;
 use std::sync::atomic::{AtomicBool, Ordering};
 use std::sync::Arc;
@@ -23,17 +23,17 @@ pub struct Stream {
 }
 
 impl Stream {
-    pub fn new(flags: FileFlags) -> Self {
+    pub fn new(flags: SocketFlags) -> Self {
         Self {
             inner: SgxMutex::new(Status::Idle(Info::new(
-                flags.contains(FileFlags::SOCK_NONBLOCK),
+                flags.contains(SocketFlags::SOCK_NONBLOCK),
             ))),
             notifier: Arc::new(RelayNotifier::new()),
         }
     }
 
-    pub fn socketpair(flags: FileFlags) -> Result<(Self, Self)> {
+    pub fn socketpair(flags: SocketFlags) -> Result<(Self, Self)> {
-        let nonblocking = flags.contains(FileFlags::SOCK_NONBLOCK);
+        let nonblocking = flags.contains(SocketFlags::SOCK_NONBLOCK);
         let (end_a, end_b) = end_pair(nonblocking)?;
         let notifier_a = Arc::new(RelayNotifier::new());
         let notifier_b = Arc::new(RelayNotifier::new());
@@ -53,15 +53,17 @@ impl Stream {
         Ok((socket_a, socket_b))
     }
 
-    pub fn addr(&self) -> Option<Addr> {
+    pub fn addr(&self) -> UnixAddr {
-        match &*self.inner() {
+        let addr_opt = match &*self.inner() {
             Status::Idle(info) => info.addr().clone(),
             Status::Connected(endpoint) => endpoint.addr(),
             Status::Listening(addr) => Some(addr).cloned(),
-        }
+        };
+
+        addr_opt.unwrap_or(UnixAddr::Unnamed)
     }
 
-    pub fn peer_addr(&self) -> Result<Addr> {
+    pub fn peer_addr(&self) -> Result<UnixAddr> {
         if let Status::Connected(endpoint) = &*self.inner() {
             if let Some(addr) = endpoint.peer_addr() {
                 return Ok(addr);
@@ -70,8 +72,8 @@ impl Stream {
         return_errno!(ENOTCONN, "the socket is not connected");
     }
 
-    pub fn bind(&self, addr: &mut Addr) -> Result<()> {
+    pub fn bind(&self, addr: &mut UnixAddr) -> Result<()> {
-        if let Addr::File(inode_num, path) = addr {
+        if let UnixAddr::File(inode_num, path) = addr {
             // create the corresponding file in the fs and fill Addr with its inode
             let corresponding_inode_num = {
                 let current = current!();
@@ -143,7 +145,7 @@ impl Stream {
 
     /// The establishment of the connection is very fast and can be done immediately.
     /// Therefore, the connect function in our implementation will never block.
-    pub fn connect(&self, addr: &Addr) -> Result<()> {
+    pub fn connect(&self, addr: &UnixAddr) -> Result<()> {
         debug!("connect to {:?}", addr);
 
         let mut inner = self.inner();
@@ -168,7 +170,7 @@ impl Stream {
                 ADDRESS_SPACE
                     .push_incoming(addr, end_incoming)
                     .map_err(|e| match e.errno() {
-                        Errno::EAGAIN => errno!(ECONNREFUSED, "the backlog is full"),
+                        EAGAIN => errno!(ECONNREFUSED, "the backlog is full"),
                         _ => e,
                     })?;
 
@@ -187,12 +189,12 @@ impl Stream {
         }
     }
 
-    pub fn accept(&self, flags: FileFlags) -> Result<(Self, Option<Addr>)> {
+    pub fn accept(&self, flags: SocketFlags) -> Result<(Self, Option<UnixAddr>)> {
         let status = (*self.inner()).clone();
         match status {
             Status::Listening(addr) => {
                 let endpoint = ADDRESS_SPACE.pop_incoming(&addr)?;
-                endpoint.set_nonblocking(flags.contains(FileFlags::SOCK_NONBLOCK));
+                endpoint.set_nonblocking(flags.contains(SocketFlags::SOCK_NONBLOCK));
                 endpoint.set_ancillary(Ancillary {
                     tid: current!().tid(),
                 });
@@ -216,12 +218,12 @@ impl Stream {
     }
 
     // TODO: handle flags
-    pub fn sendto(&self, buf: &[u8], flags: SendFlags, addr: &Option<Addr>) -> Result<usize> {
+    pub fn sendto(&self, buf: &[u8], flags: SendFlags, addr: &Option<UnixAddr>) -> Result<usize> {
         self.write(buf)
     }
 
     // TODO: handle flags
-    pub fn recvfrom(&self, buf: &mut [u8], flags: RecvFlags) -> Result<(usize, Option<Addr>)> {
+    pub fn recvfrom(&self, buf: &mut [u8], flags: RecvFlags) -> Result<(usize, Option<UnixAddr>)> {
         let data_len = self.read(buf)?;
         let addr = self.peer_addr().ok();
 
@@ -230,33 +232,39 @@ impl Stream {
         Ok((data_len, addr))
     }
 
-    pub fn sendmsg(&self, msg_hdr: &MsgHdr, flags: SendFlags) -> Result<usize> {
+    pub fn sendmsg(
+        &self,
+        bufs: &[&[u8]],
+        flags: SendFlags,
+        control: Option<&[u8]>,
+    ) -> Result<usize> {
         if !flags.is_empty() {
             warn!("unsupported flags: {:?}", flags);
         }
 
-        let bufs = msg_hdr.get_iovs().as_slices();
+        let data_len = self.writev(bufs)?;
-        let mut data_len = self.writev(bufs)?;
+        if let Some(msg_control) = control {
-
+            self.write(msg_control)?;
-        if let Some(msg_control) = msg_hdr.get_control() {
-            data_len += self.write(msg_control)?;
         }
+
         Ok(data_len)
     }
 
-    pub fn recvmsg(&self, msg_hdr: &mut MsgHdrMut, flags: RecvFlags) -> Result<usize> {
+    pub fn recvmsg(
+        &self,
+        bufs: &mut [&mut [u8]],
+        flags: RecvFlags,
+        control: Option<&mut [u8]>,
+    ) -> Result<(usize, usize)> {
         if !flags.is_empty() {
             warn!("unsupported flags: {:?}", flags);
         }
 
-        let bufs = msg_hdr.get_iovs_mut().as_slices_mut();
+        let data_len = self.readv(bufs)?;
-        let mut data_len = self.readv(bufs)?;
 
         // For stream socket, the msg_name is ignored. And other fields are not supported.
-        msg_hdr.set_name_len(0);
+        let control_len = if let Some(msg_control) = control {
-
+            let control_len = self.read(msg_control)?;
-        if let Some(msg_control) = msg_hdr.get_control_mut() {
-            data_len += self.read(msg_control)?;
 
             // For each control message that contains file descriptors (SOL_SOCKET and SCM_RIGHTS),
             // reassign each fd in the message in receive end.
@@ -268,7 +276,6 @@ impl Stream {
                             .unwrap()
                             .files()
                             .lock()
-                            .unwrap()
                             .get(send_fd)
                             .unwrap();
                         current!().add_file(ipc_file.clone(), false)
@@ -276,12 +283,16 @@ impl Stream {
                 }
                 // Unix credentials need not to be handled here
             }
-        }
+            control_len
-        Ok(data_len)
+        } else {
+            0
+        };
+
+        Ok((data_len, control_len))
     }
 
     /// perform shutdown on the socket.
-    pub fn shutdown(&self, how: HowToShut) -> Result<()> {
+    pub fn shutdown(&self, how: Shutdown) -> Result<()> {
         if let Status::Connected(ref end) = &*self.inner() {
             end.shutdown(how)
         } else {
@@ -369,13 +380,13 @@ pub enum Status {
     Idle(Info),
     // The listeners are stored in a global data structure indexed by the address.
     // The consitency of Status with that data structure should be carefully maintained.
-    Listening(Addr),
+    Listening(UnixAddr),
     Connected(Endpoint),
 }
 
 #[derive(Debug, Clone)]
 pub struct Info {
-    addr: Option<Addr>,
+    addr: Option<UnixAddr>,
     nonblocking: bool,
 }
 
@@ -387,11 +398,11 @@ impl Info {
         }
     }
 
-    pub fn addr(&self) -> &Option<Addr> {
+    pub fn addr(&self) -> &Option<UnixAddr> {
         &self.addr
     }
 
-    pub fn set_addr(&mut self, addr: &Addr) {
+    pub fn set_addr(&mut self, addr: &UnixAddr) {
         self.addr = Some(addr.clone());
     }
 

src/libos/src/net/socket/util/addr/c_sock_addr.rs

@@ -0,0 +1,134 @@
+use crate::prelude::*;
+use std::mem::{size_of, size_of_val, MaybeUninit};
+/// A trait for all C version of C socket addresses.
+///
+/// There are four types that implement this trait:
+/// * `libc::sockaddr_in`
+/// * `(libc::sockaddr_in, usize)`
+/// * `(libc::sockaddr_un, usize)`
+/// * `(libc::sockaddr_storage, usize)`.
+pub trait CSockAddr {
+    /// The network family of the address.
+    fn c_family(&self) -> libc::sa_family_t;
+
+    /// The address in bytes (excluding the family part).
+    fn c_addr(&self) -> &[u8];
+
+    /// Returns the address in `libc::sockaddr_storage` along with its length.
+    fn to_c_storage(&self) -> (libc::sockaddr_storage, usize) {
+        let mut c_storage =
+            unsafe { MaybeUninit::<libc::sockaddr_storage>::uninit().assume_init() };
+
+        c_storage.ss_family = self.c_family();
+        let offset = size_of_val(&c_storage.ss_family);
+
+        let c_storage_len = offset + self.c_addr().len();
+        assert!(c_storage_len <= size_of::<libc::sockaddr_storage>());
+
+        let c_storage_remain = unsafe {
+            let ptr = (&mut c_storage as *mut _ as *mut u8).add(offset);
+            let len = self.c_addr().len();
+            std::slice::from_raw_parts_mut(ptr, len)
+        };
+        c_storage_remain.copy_from_slice(self.c_addr());
+        (c_storage, c_storage_len)
+    }
+}
+
+impl CSockAddr for libc::sockaddr_in {
+    fn c_family(&self) -> libc::sa_family_t {
+        libc::AF_INET as _
+    }
+
+    fn c_addr(&self) -> &[u8] {
+        // Safety. The slice is part of self.
+        unsafe {
+            let addr_ptr = (self as *const _ as *const u8).add(size_of_val(&self.sin_family));
+            std::slice::from_raw_parts(
+                addr_ptr,
+                size_of::<libc::sockaddr_in>() - size_of_val(&self.sin_family),
+            )
+        }
+    }
+}
+
+impl CSockAddr for (libc::sockaddr_in, usize) {
+    fn c_family(&self) -> libc::sa_family_t {
+        self.0.c_family()
+    }
+
+    fn c_addr(&self) -> &[u8] {
+        assert!(self.1 == size_of::<libc::sockaddr_in>());
+        self.0.c_addr()
+    }
+}
+
+impl CSockAddr for (libc::sockaddr_in6, usize) {
+    fn c_family(&self) -> libc::sa_family_t {
+        self.0.sin6_family
+    }
+
+    fn c_addr(&self) -> &[u8] {
+        assert!(self.1 == size_of::<libc::sockaddr_in6>());
+        unsafe {
+            let addr_ptr = (&self.0 as *const _ as *const u8).add(size_of_val(&self.c_family()));
+            std::slice::from_raw_parts(
+                addr_ptr,
+                size_of::<libc::sockaddr_in6>() - size_of_val(&self.c_family()),
+            )
+        }
+    }
+}
+
+impl CSockAddr for (libc::sockaddr_un, usize) {
+    fn c_family(&self) -> libc::sa_family_t {
+        libc::AF_UNIX as _
+    }
+
+    fn c_addr(&self) -> &[u8] {
+        assert!(
+            size_of::<libc::sa_family_t>() <= self.1 && self.1 <= size_of::<libc::sockaddr_un>()
+        );
+        // Safety. The slice is part of self.
+        unsafe {
+            let addr_ptr = (&self.0 as *const _ as *const u8).add(size_of_val(&self.0.sun_family));
+            std::slice::from_raw_parts(addr_ptr, self.1 - size_of_val(&self.0.sun_family))
+        }
+    }
+}
+
+impl CSockAddr for (libc::sockaddr_nl, usize) {
+    fn c_family(&self) -> libc::sa_family_t {
+        libc::AF_NETLINK as _
+    }
+
+    fn c_addr(&self) -> &[u8] {
+        assert!(self.1 == size_of::<libc::sockaddr_nl>());
+
+        unsafe {
+            let addr_ptr = (&self.0 as *const _ as *const u8).add(size_of_val(&self.c_family()));
+            std::slice::from_raw_parts(
+                addr_ptr,
+                size_of::<libc::sockaddr_nl>() - size_of_val(&self.c_family()),
+            )
+        }
+    }
+}
+
+impl CSockAddr for (libc::sockaddr_storage, usize) {
+    fn c_family(&self) -> libc::sa_family_t {
+        self.0.ss_family
+    }
+
+    fn c_addr(&self) -> &[u8] {
+        assert!(
+            size_of::<libc::sa_family_t>() <= self.1
+                && self.1 <= size_of::<libc::sockaddr_storage>()
+        );
+        // Safety. The slice is part of self.
+        unsafe {
+            let addr_ptr = (&self.0 as *const _ as *const u8).add(size_of_val(&self.0.ss_family));
+            std::slice::from_raw_parts(addr_ptr, self.1 - size_of_val(&self.0.ss_family))
+        }
+    }
+}

src/libos/src/net/socket/util/addr/ipv4.rs

@@ -0,0 +1,137 @@
+use std::any::Any;
+use std::fmt::{self, Debug};
+
+use super::{Addr, CSockAddr, Domain, RawAddr};
+use crate::prelude::*;
+
+/// An IPv4 socket address, consisting of an IPv4 address and a port.
+#[derive(Copy, Clone, Debug, PartialEq, Eq)]
+pub struct Ipv4SocketAddr {
+    ip: Ipv4Addr,
+    port: u16,
+}
+
+impl Addr for Ipv4SocketAddr {
+    fn domain() -> Domain {
+        Domain::INET
+    }
+
+    fn from_c_storage(c_addr: &libc::sockaddr_storage, c_addr_len: usize) -> Result<Self> {
+        if c_addr_len > std::mem::size_of::<libc::sockaddr_storage>() {
+            return_errno!(EINVAL, "address length is too large");
+        }
+
+        // The c_addr_len is certainly not smaller than the length of IN_ADDR_ANY.
+        // https://en.wikipedia.org/wiki/IPv4
+        if c_addr_len < std::mem::size_of::<libc::sockaddr_in>() {
+            return_errno!(EINVAL, "address length is too small");
+        }
+        // Safe to convert from sockaddr_storage to sockaddr_in
+        let c_addr = unsafe { std::mem::transmute(c_addr) };
+        Self::from_c(c_addr)
+    }
+
+    fn to_c_storage(&self) -> (libc::sockaddr_storage, usize) {
+        let c_in_addr = self.to_c();
+        c_in_addr.to_c_storage()
+    }
+
+    fn as_any(&self) -> &dyn Any {
+        self
+    }
+
+    fn is_default(&self) -> bool {
+        let inaddr_any = Self::default();
+        *self == inaddr_any
+    }
+}
+
+impl Ipv4SocketAddr {
+    pub fn new(ip: Ipv4Addr, port: u16) -> Self {
+        Self { ip, port }
+    }
+
+    pub fn from_c(c_addr: &libc::sockaddr_in) -> Result<Self> {
+        if c_addr.sin_family != libc::AF_INET as libc::sa_family_t {
+            return_errno!(EINVAL, "an ipv4 address is expected");
+        }
+        Ok(Self {
+            port: u16::from_be(c_addr.sin_port),
+            ip: Ipv4Addr::from_c(&c_addr.sin_addr),
+        })
+    }
+
+    pub fn to_c(&self) -> libc::sockaddr_in {
+        libc::sockaddr_in {
+            sin_family: libc::AF_INET as _,
+            sin_port: self.port.to_be(),
+            sin_addr: self.ip.to_c(),
+            sin_zero: [0; 8],
+        }
+    }
+
+    pub fn to_raw(&self) -> RawAddr {
+        let (storage, len) = self.to_c_storage();
+        RawAddr::from_c_storage(&storage, len)
+    }
+
+    pub fn ip(&self) -> &Ipv4Addr {
+        &self.ip
+    }
+
+    pub fn port(&self) -> u16 {
+        self.port
+    }
+
+    pub fn set_ip(&mut self, new_ip: Ipv4Addr) {
+        self.ip = new_ip;
+    }
+
+    pub fn set_port(&mut self, new_port: u16) {
+        self.port = new_port;
+    }
+}
+
+impl Default for Ipv4SocketAddr {
+    fn default() -> Self {
+        let addr = Ipv4Addr::new(0, 0, 0, 0);
+        Self::new(addr, 0)
+    }
+}
+
+/// An Ipv4 address.
+#[derive(Copy, Clone, PartialEq, Eq)]
+pub struct Ipv4Addr([u8; 4] /* big endian */);
+
+impl Ipv4Addr {
+    /// Creates a new IPv4 address of `a.b.c.d`.
+    pub fn new(a: u8, b: u8, c: u8, d: u8) -> Self {
+        Self([a, b, c, d])
+    }
+
+    /// Creates a new IPv4 address from its C counterpart.
+    pub fn from_c(c_addr: &libc::in_addr) -> Self {
+        Self(c_addr.s_addr.to_ne_bytes())
+    }
+
+    /// Return the C counterpart.
+    pub fn to_c(&self) -> libc::in_addr {
+        libc::in_addr {
+            s_addr: u32::from_ne_bytes(self.0),
+        }
+    }
+
+    /// Return the four digits that make up the address.
+    ///
+    /// Assuming the address is `a.b.c.d`, the returned value would be `[a, b, c, d]`.
+    pub fn octets(&self) -> &[u8; 4] {
+        &self.0
+    }
+}
+
+impl fmt::Debug for Ipv4Addr {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        let [a, b, c, d] = *self.octets();
+        write!(f, "Ipv4Addr ({}.{}.{}.{})", &a, &b, &c, &d)
+    }
+}

src/libos/src/net/socket/util/addr/ipv6.rs

@@ -0,0 +1,115 @@
+use std::any::Any;
+use std::fmt::Debug;
+
+use super::RawAddr;
+use super::{Addr, CSockAddr, Domain};
+use crate::prelude::*;
+use libc::in6_addr;
+use libc::sockaddr_in6;
+
+pub use std::net::Ipv6Addr;
+
+#[derive(Copy, Clone, Debug, PartialEq, Eq)]
+pub struct Ipv6SocketAddr {
+    ip: Ipv6Addr,
+    port: u16,
+    flowinfo: u32,
+    scope_id: u32,
+}
+
+impl Addr for Ipv6SocketAddr {
+    fn domain() -> Domain {
+        Domain::INET6
+    }
+
+    fn from_c_storage(c_addr: &libc::sockaddr_storage, c_addr_len: usize) -> Result<Self> {
+        if c_addr_len > std::mem::size_of::<libc::sockaddr_storage>() {
+            return_errno!(EINVAL, "address length is too large");
+        }
+
+        if c_addr_len < std::mem::size_of::<sockaddr_in6>() {
+            return_errno!(EINVAL, "address length is too small");
+        }
+        // Safe to convert from sockaddr_storage to sockaddr_in
+        let c_addr: &sockaddr_in6 = unsafe { std::mem::transmute(c_addr) };
+        Self::from_c(c_addr)
+    }
+
+    fn to_c_storage(&self) -> (libc::sockaddr_storage, usize) {
+        let c_addr = self.to_c();
+        (c_addr, std::mem::size_of::<libc::sockaddr_in6>()).to_c_storage()
+    }
+
+    fn as_any(&self) -> &dyn Any {
+        self
+    }
+
+    fn is_default(&self) -> bool {
+        let in6addr_any_init = Self::default();
+        *self == in6addr_any_init
+    }
+}
+
+impl Ipv6SocketAddr {
+    pub fn new(ip: Ipv6Addr, port: u16, flowinfo: u32, scope_id: u32) -> Self {
+        Self {
+            ip,
+            port,
+            flowinfo,
+            scope_id,
+        }
+    }
+
+    pub fn from_c(c_addr: &libc::sockaddr_in6) -> Result<Self> {
+        if c_addr.sin6_family != libc::AF_INET6 as libc::sa_family_t {
+            return_errno!(EINVAL, "an ipv6 address is expected");
+        }
+        Ok(Self {
+            port: u16::from_be(c_addr.sin6_port),
+            ip: Ipv6Addr::from(c_addr.sin6_addr.s6_addr),
+            flowinfo: u32::from_be(c_addr.sin6_flowinfo),
+            scope_id: u32::from_be(c_addr.sin6_scope_id),
+        })
+    }
+
+    pub fn to_c(&self) -> libc::sockaddr_in6 {
+        let in6_addr = in6_addr {
+            s6_addr: self.ip.octets(),
+        };
+        libc::sockaddr_in6 {
+            sin6_family: libc::AF_INET6 as _,
+            sin6_port: self.port.to_be(),
+            sin6_addr: in6_addr,
+            sin6_flowinfo: self.flowinfo.to_be(),
+            sin6_scope_id: self.flowinfo.to_be(),
+        }
+    }
+
+    pub fn to_raw(&self) -> RawAddr {
+        let (storage, len) = self.to_c_storage();
+        RawAddr::from_c_storage(&storage, len)
+    }
+
+    pub fn ip(&self) -> &Ipv6Addr {
+        &self.ip
+    }
+
+    pub fn port(&self) -> u16 {
+        self.port
+    }
+
+    pub fn set_ip(&mut self, new_ip: Ipv6Addr) {
+        self.ip = new_ip;
+    }
+
+    pub fn set_port(&mut self, new_port: u16) {
+        self.port = new_port;
+    }
+}
+
+impl Default for Ipv6SocketAddr {
+    fn default() -> Self {
+        let addr = Ipv6Addr::new(0, 0, 0, 0, 0, 0, 0, 0);
+        Self::new(addr, 0, 0, 0)
+    }
+}

src/libos/src/net/socket/util/addr/mod.rs

@@ -0,0 +1,87 @@
+use std::any::Any;
+use std::fmt::Debug;
+
+use crate::net::Domain;
+use crate::prelude::*;
+
+mod c_sock_addr;
+mod ipv4;
+mod ipv6;
+mod raw_addr;
+mod unix_addr;
+
+/// A trait for network addresses.
+pub trait Addr: Clone + Debug + Default + PartialEq + Send + Sync {
+    /// Return the domain that the address belongs to.
+    fn domain() -> Domain
+    where
+        Self: Sized;
+
+    /// Construct a new address from C's sockaddr_storage.
+    ///
+    /// The length argument specify how much bytes in the given sockaddr_storage are to be
+    /// interpreted as parts of the address.
+    fn from_c_storage(c_addr: &libc::sockaddr_storage, c_addr_len: usize) -> Result<Self>
+    where
+        Self: Sized;
+
+    /// Converts the address to C's sockaddr_storage.
+    ///
+    /// The actual length used in sockaddr_storage is also returned.
+    fn to_c_storage(&self) -> (libc::sockaddr_storage, usize);
+
+    fn as_any(&self) -> &dyn Any;
+
+    fn is_default(&self) -> bool;
+}
+
+pub use self::c_sock_addr::CSockAddr;
+pub use self::ipv4::{Ipv4Addr, Ipv4SocketAddr};
+pub use self::ipv6::{Ipv6Addr, Ipv6SocketAddr};
+pub use self::raw_addr::RawAddr;
+pub use self::unix_addr::UnixAddr;
+
+#[cfg(test)]
+mod tests {
+    use std::mem::size_of;
+
+    use super::*;
+
+    #[test]
+    fn ipv4_to_and_from_c() {
+        let addr = [127u8, 0, 0, 1];
+        let port = 8888u16;
+
+        let c_addr = libc::sockaddr_in {
+            sin_family: libc::AF_INET as _,
+            sin_port: port.to_be(),
+            sin_addr: libc::in_addr {
+                s_addr: u32::from_be_bytes(addr).to_be(),
+            },
+            sin_zero: [0u8; 8],
+        };
+
+        let addr = {
+            let addr = Ipv4Addr::new(addr[0], addr[1], addr[2], addr[3]);
+            Ipv4SocketAddr::new(addr, port)
+        };
+
+        check_to_and_from_c(&c_addr, &addr);
+    }
+
+    fn check_to_and_from_c<T: CSockAddr, U: Addr>(c_addr: &T, addr: &U) {
+        let c_addr_storage = c_addr.to_c_storage();
+
+        // To C
+        assert!(are_sock_addrs_equal(c_addr, &addr.to_c_storage()));
+        assert!(are_sock_addrs_equal(&c_addr_storage, &addr.to_c_storage()));
+
+        // From C
+        let (c_addr_storage, c_addr_len) = c_addr_storage;
+        assert!(&U::from_c_storage(&c_addr_storage, c_addr_len).unwrap() == addr);
+    }
+
+    fn are_sock_addrs_equal<T: CSockAddr, U: CSockAddr>(one: &T, other: &U) -> bool {
+        one.c_family() == other.c_family() && one.c_addr() == other.c_addr()
+    }
+}

src/libos/src/net/socket/util/addr/raw_addr.rs

@@ -2,25 +2,33 @@ use super::*;
 use std::*;
 
 #[derive(Copy, Clone)]
-pub struct SockAddr {
+pub struct RawAddr {
     storage: libc::sockaddr_storage,
     len: usize,
 }
 
 // TODO: add more fields
-impl fmt::Debug for SockAddr {
+impl fmt::Debug for RawAddr {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        f.debug_struct("SockAddr")
+        f.debug_struct("RawAddr")
-            .field(
+            .field("family", &Domain::try_from(self.storage.ss_family).unwrap())
-                "family",
-                &AddressFamily::try_from(self.storage.ss_family).unwrap(),
-            )
             .field("len", &self.len)
             .finish()
     }
 }
 
-impl SockAddr {
+impl RawAddr {
+    pub fn from_c_storage(c_addr: &libc::sockaddr_storage, c_addr_len: usize) -> Self {
+        Self {
+            storage: *c_addr,
+            len: c_addr_len,
+        }
+    }
+
+    pub fn to_c_storage(&self) -> (libc::sockaddr_storage, usize) {
+        (self.storage, self.len)
+    }
+
     // Caller should guarentee the sockaddr and addr_len are valid
     pub unsafe fn try_from_raw(
         sockaddr: *const libc::sockaddr,
@@ -34,13 +42,13 @@ impl SockAddr {
             return_errno!(EINVAL, "the address is too long.");
         }
 
-        match AddressFamily::try_from((*sockaddr).sa_family)? {
+        match Domain::try_from((*sockaddr).sa_family)? {
-            AddressFamily::INET => {
+            Domain::INET => {
                 if addr_len < std::mem::size_of::<libc::sockaddr_in>() as u32 {
                     return_errno!(EINVAL, "short ipv4 address.");
                 }
             }
-            AddressFamily::INET6 => {
+            Domain::INET6 => {
                 let ipv6_addr_len = std::mem::size_of::<libc::sockaddr_in6>() as u32;
                 // Omit sin6_scope_id when it is not fully provided
                 // 4 represents the size of sin6_scope_id which is not a must
@@ -110,7 +118,7 @@ impl SockAddr {
     }
 }
 
-impl Default for SockAddr {
+impl Default for RawAddr {
     fn default() -> Self {
         let mut storage: libc::sockaddr_storage = unsafe { mem::zeroed() };
         Self {

src/libos/src/net/socket/util/addr/unix_addr.rs

@@ -0,0 +1,212 @@
+use crate::net::socket::CSockAddr;
+
+use super::*;
+use sgx_trts::c_str::CStr;
+use std::path::{Path, PathBuf};
+use std::{cmp, mem, slice, str};
+
+const MAX_PATH_LEN: usize = 108;
+const SUN_FAMILY_LEN: usize = mem::size_of::<libc::sa_family_t>();
+lazy_static! {
+    static ref SUN_PATH_OFFSET: usize = memoffset::offset_of!(libc::sockaddr_un, sun_path);
+}
+
+#[derive(Clone, Debug, Eq, PartialEq)]
+pub enum UnixAddr {
+    Unnamed,
+    File(Option<usize>, UnixPath), // An optional inode number and path. Use inode if there is one.
+    Abstract(String),
+}
+
+impl UnixAddr {
+    /// Construct a unix address from its C counterpart.
+    ///
+    /// The argument `c_len` specifies the length of the valid part in the given
+    /// C address.
+    pub fn from_c(c_addr: &libc::sockaddr_un, c_len: usize) -> Result<Self> {
+        // Sanity checks
+        if c_addr.sun_family != libc::AF_UNIX as libc::sa_family_t {
+            return_errno!(EINVAL, "an unix address is expected");
+        }
+        if c_len < std::mem::size_of::<libc::sa_family_t>() {
+            return_errno!(EINVAL, "the length of the address is too small");
+        } else if c_len > std::mem::size_of::<libc::sockaddr_un>() {
+            return_errno!(EINVAL, "the length of the address is too large");
+        }
+
+        if c_len == std::mem::size_of::<libc::sa_family_t>() {
+            return Ok(Self::Unnamed);
+        }
+
+        let path_len = c_len - std::mem::size_of::<libc::sa_family_t>();
+        debug_assert!(path_len > 1);
+        if path_len == 1 {
+            // Both pathname and abstract addresses require a path_len greater than 1.
+            return_errno!(EINVAL, "the pathname must not be empty");
+        }
+
+        // A pathname address
+        if c_addr.sun_path[0] != 0 {
+            // More sanity check
+            let last_char = c_addr.sun_path[path_len - 1];
+            if last_char != 0 {
+                return_errno!(EINVAL, "the pathname is not null-terminated");
+            }
+
+            let pathname = {
+                // Safety. Converting from &[c_char] to &[i8] is harmless.
+                let path_slice: &[i8] = unsafe {
+                    let char_slice = &c_addr.sun_path[..(path_len - 1)];
+                    std::mem::transmute(char_slice)
+                };
+                let path_cstr = unsafe { CStr::from_ptr(path_slice.as_ptr()) };
+                if path_cstr.to_bytes_with_nul().len() > MAX_PATH_LEN {
+                    return_errno!(EINVAL, "no null in the address");
+                }
+                path_cstr
+                    .to_str()
+                    .map_err(|_| errno!(EINVAL, "path is not UTF8"))?
+                    .to_string()
+            };
+
+            Ok(Self::File(None, UnixPath::new(&pathname)))
+        }
+        // An abstract address
+        else {
+            // Safety. Converting from &[c_char] to &[u8] is harmless.
+            let u8_slice: &[u8] = unsafe {
+                let char_slice = &c_addr.sun_path[1..(path_len)];
+                std::mem::transmute(char_slice)
+            };
+            Ok(Self::Abstract(
+                str::from_utf8(u8_slice).unwrap().to_string(),
+            ))
+        }
+    }
+
+    pub fn from_c_storage(c_addr: &libc::sockaddr_storage, c_addr_len: usize) -> Result<Self> {
+        if (c_addr_len) > std::mem::size_of::<libc::sockaddr_storage>() {
+            return_errno!(EINVAL, "address length is too large");
+        }
+        // Safety. Convert from sockaddr_storage to sockaddr_un is harmless.
+        let c_addr = unsafe { std::mem::transmute(c_addr) };
+        unsafe { Self::from_c(c_addr, c_addr_len) }
+    }
+
+    pub fn copy_to_slice(&self, dst: &mut [u8]) -> usize {
+        let (raw_addr, addr_len) = self.to_c();
+        let src =
+            unsafe { std::slice::from_raw_parts(&raw_addr as *const _ as *const u8, addr_len) };
+        let copied = std::cmp::min(dst.len(), addr_len);
+        dst[..copied].copy_from_slice(&src[..copied]);
+        copied
+    }
+
+    pub fn raw_len(&self) -> usize {
+        /// The '/0' at the end of Self::File counts
+        match self.path_str() {
+            Ok(str) => str.len() + 1 + *SUN_PATH_OFFSET,
+            Err(_) => 0,
+        }
+    }
+
+    pub fn path_str(&self) -> Result<&str> {
+        match self {
+            Self::File(_, unix_path) => Ok(&unix_path.path_str()),
+            Self::Abstract(path) => Ok(&path),
+            Self::Unnamed => return_errno!(EINVAL, "can't get path name for unnamed socket"),
+        }
+    }
+
+    pub fn to_c_storage(&self) -> (libc::sockaddr_storage, usize) {
+        let c_un_addr = self.to_c();
+        c_un_addr.to_c_storage()
+    }
+
+    pub fn to_raw(&self) -> RawAddr {
+        let (storage, addr_len) = self.to_c_storage();
+        RawAddr::from_c_storage(&storage, addr_len)
+    }
+
+    fn to_c(&self) -> (libc::sockaddr_un, usize) {
+        const FAMILY_LEN: usize = std::mem::size_of::<libc::sa_family_t>();
+
+        let mut addr: libc::sockaddr_un = unsafe { mem::zeroed() };
+        addr.sun_family = Domain::LOCAL as libc::sa_family_t;
+
+        let addr_len = match self {
+            Self::Unnamed => FAMILY_LEN,
+            Self::File(_, unix_path) => {
+                let path_str = unix_path.path_str();
+                let buf_len = path_str.len();
+                /// addr is initialized to all zeros and try_from_raw guarentees
+                /// unix_path length is shorter than sun_path, so sun_path here
+                /// will always have a null terminator
+                addr.sun_path[..buf_len]
+                    .copy_from_slice(unsafe { &*(path_str.as_bytes() as *const _ as *const [i8]) });
+                buf_len + *SUN_PATH_OFFSET + 1
+            }
+            Self::Abstract(path_str) => {
+                addr.sun_path[0] = 0;
+                let buf_len = path_str.len() + 1;
+                addr.sun_path[1..buf_len]
+                    .copy_from_slice(unsafe { &*(path_str.as_bytes() as *const _ as *const [i8]) });
+                buf_len + *SUN_PATH_OFFSET
+            }
+        };
+
+        (addr, addr_len)
+    }
+}
+
+impl Default for UnixAddr {
+    fn default() -> Self {
+        UnixAddr::Unnamed
+    }
+}
+
+#[derive(Clone, Debug, Eq, PartialEq)]
+pub struct UnixPath {
+    inner: PathBuf,
+    /// Holds the cwd when a relative path is created
+    cwd: Option<String>,
+}
+
+impl UnixPath {
+    pub fn new(path: &str) -> Self {
+        let inner = PathBuf::from(path);
+        let is_absolute = inner.is_absolute();
+        Self {
+            inner: inner,
+            cwd: if is_absolute {
+                None
+            } else {
+                let thread = current!();
+                let fs = thread.fs().read().unwrap();
+                let cwd = fs.cwd().to_owned();
+
+                Some(cwd)
+            },
+        }
+    }
+
+    pub fn absolute(&self) -> String {
+        let path_str = self.path_str();
+        if self.inner.is_absolute() {
+            path_str.to_string()
+        } else {
+            let mut prefix = self.cwd.as_ref().unwrap().clone();
+            if prefix.ends_with("/") {
+                prefix.push_str(path_str);
+            } else {
+                prefix.push_str("/");
+                prefix.push_str(path_str);
+            }
+            prefix
+        }
+    }
+
+    pub fn path_str(&self) -> &str {
+        self.inner.to_str().unwrap()
+    }
+}

src/libos/src/net/socket/util/any_addr.rs

@@ -0,0 +1,113 @@
+use std::mem::{self, MaybeUninit};
+
+use crate::net::socket::Domain;
+use crate::prelude::*;
+
+use super::{Addr, CSockAddr, Ipv4Addr, Ipv4SocketAddr, Ipv6SocketAddr, RawAddr, UnixAddr};
+use num_enum::IntoPrimitive;
+use std::path::Path;
+
+#[derive(Clone, Debug)]
+pub enum AnyAddr {
+    Ipv4(Ipv4SocketAddr),
+    Ipv6(Ipv6SocketAddr),
+    Unix(UnixAddr),
+    Raw(RawAddr),
+    Unspec,
+}
+
+impl AnyAddr {
+    pub fn from_c_storage(c_addr: &libc::sockaddr_storage, c_addr_len: usize) -> Result<Self> {
+        let any_addr = match c_addr.ss_family as _ {
+            libc::AF_INET => {
+                let ipv4_addr = Ipv4SocketAddr::from_c_storage(c_addr, c_addr_len)?;
+                Self::Ipv4(ipv4_addr)
+            }
+            libc::AF_INET6 => {
+                let ipv6_addr = Ipv6SocketAddr::from_c_storage(c_addr, c_addr_len)?;
+                Self::Ipv6(ipv6_addr)
+            }
+            libc::AF_UNSPEC => Self::Unspec,
+            libc::AF_UNIX | libc::AF_LOCAL => {
+                let unix_addr = UnixAddr::from_c_storage(c_addr, c_addr_len)?;
+                Self::Unix(unix_addr)
+            }
+            _ => {
+                let raw_addr = RawAddr::from_c_storage(c_addr, c_addr_len);
+                Self::Raw(raw_addr)
+            }
+        };
+        Ok(any_addr)
+    }
+
+    pub fn to_c_storage(&self) -> (libc::sockaddr_storage, usize) {
+        match self {
+            Self::Ipv4(ipv4_addr) => ipv4_addr.to_c_storage(),
+            Self::Ipv6(ipv6_addr) => ipv6_addr.to_c_storage(),
+            Self::Unix(unix_addr) => unix_addr.to_c_storage(),
+            Self::Raw(raw_addr) => raw_addr.to_c_storage(),
+            Self::Unspec => {
+                let mut sockaddr_storage =
+                    unsafe { MaybeUninit::<libc::sockaddr_storage>::uninit().assume_init() };
+                sockaddr_storage.ss_family = libc::AF_UNSPEC as _;
+                (sockaddr_storage, mem::size_of::<libc::sa_family_t>())
+            }
+        }
+    }
+
+    pub fn to_raw(&self) -> RawAddr {
+        match self {
+            Self::Ipv4(ipv4_addr) => ipv4_addr.to_raw(),
+            Self::Ipv6(ipv6_addr) => ipv6_addr.to_raw(),
+            Self::Unix(unix_addr) => unix_addr.to_raw(),
+            Self::Raw(raw_addr) => *raw_addr,
+            Self::Unspec => {
+                let mut sockaddr_storage =
+                    unsafe { MaybeUninit::<libc::sockaddr_storage>::uninit().assume_init() };
+                sockaddr_storage.ss_family = libc::AF_UNSPEC as _;
+                RawAddr::from_c_storage(&sockaddr_storage, mem::size_of::<libc::sa_family_t>())
+            }
+        }
+    }
+
+    pub fn to_unix(&self) -> Result<&UnixAddr> {
+        match self {
+            Self::Unix(unix_addr) => Ok(unix_addr),
+            _ => return_errno!(EAFNOSUPPORT, "not unix address"),
+        }
+    }
+
+    pub fn as_ipv4(&self) -> Option<&Ipv4SocketAddr> {
+        match self {
+            Self::Ipv4(ipv4_addr) => Some(ipv4_addr),
+            _ => None,
+        }
+    }
+
+    pub fn to_ipv4(&self) -> Result<&Ipv4SocketAddr> {
+        match self {
+            Self::Ipv4(ipv4_addr) => Ok(ipv4_addr),
+            _ => return_errno!(EAFNOSUPPORT, "not ipv4 address"),
+        }
+    }
+
+    pub fn to_ipv6(&self) -> Result<&Ipv6SocketAddr> {
+        match self {
+            Self::Ipv6(ipv6_addr) => Ok(ipv6_addr),
+            _ => return_errno!(EAFNOSUPPORT, "not ipv6 address"),
+        }
+    }
+
+    pub fn is_unspec(&self) -> bool {
+        match self {
+            Self::Unspec => true,
+            _ => false,
+        }
+    }
+
+    pub fn as_slice(&self) -> &[u8] {
+        let (storage, len) = self.to_c_storage();
+        let addr = &storage as *const _ as *const _;
+        unsafe { std::slice::from_raw_parts(addr as *const u8, len) }
+    }
+}

src/libos/src/net/socket/util/domain.rs

@@ -1,10 +1,11 @@
 use super::*;
+use num_enum::{IntoPrimitive, TryFromPrimitive};
 
 // The protocol family generally is the same as the address family
-#[derive(Copy, Clone, Debug, PartialEq, Eq)]
+#[derive(Copy, Clone, Debug, PartialEq, Eq, IntoPrimitive, TryFromPrimitive)]
 #[repr(u16)]
 #[allow(non_camel_case_types)]
-pub enum AddressFamily {
+pub enum Domain {
     UNSPEC = 0,
     LOCAL = 1,
     /* Hide the families with the same number
@@ -60,7 +61,7 @@ pub enum AddressFamily {
     MAX = 45,
 }
 
-impl AddressFamily {
+impl Domain {
     pub fn try_from(af: u16) -> Result<Self> {
         if af >= Self::MAX as u16 {
             return_errno!(EINVAL, "Unknown address family");

src/libos/src/net/socket/util/flags.rs

@@ -0,0 +1,39 @@
+use bitflags::bitflags;
+
+// Flags to use when sending data through a socket
+bitflags! {
+    pub struct SendFlags: i32 {
+        const MSG_OOB          = 0x01;      // Sends out-of-band data on sockets
+        const MSG_DONTROUTE    = 0x04;      // Don't use a gateway to send out the packet
+        const MSG_DONTWAIT     = 0x40;      // Nonblocking io
+        const MSG_EOR          = 0x80;      // End of record
+        const MSG_CONFIRM      = 0x0800;    // Confirm path validity
+        const MSG_NOSIGNAL     = 0x4000;    // Do not generate SIGPIPE
+        const MSG_MORE         = 0x8000;    // Sender will send more
+    }
+}
+
+// Flags to use when receiving data through a socket
+bitflags! {
+    pub struct RecvFlags: i32 {
+        const MSG_OOB          = 0x01;          // Recv out-of-band data
+        const MSG_PEEK         = 0x02;          // Return data without removing that
+        const MSG_TRUNC        = 0x20;          // Return the real length of the packet or datagram
+        const MSG_DONTWAIT     = 0x40;          // Nonblocking io
+        const MSG_WAITALL      = 0x0100;        // Wait for a full request
+        const MSG_ERRQUEUE     = 0x2000;        // Fetch message from error queue
+        // recvmsg only
+        const MSG_CMSG_CLOEXEC = 0x40000000;    // Set close_on_exec for file descriptor received through SCM_RIGHTS
+    }
+}
+
+bitflags! {
+    pub struct MsgFlags: i32 {
+        const MSG_OOB          = 0x01;      // Expedited or out-of-band data was received
+        const MSG_CTRUNC       = 0x08;      // Some control data was discarded
+        const MSG_TRUNC        = 0x20;      // The trailing portion of a datagram was discarded
+        const MSG_EOR          = 0x80;      // End of record
+        const MSG_ERRQUEUE     = 0x2000;    // Fetch message from error queue
+        const MSG_NOTIFICATION = 0x8000;     // Only applicable to SCTP socket
+    }
+}

src/libos/src/net/socket/util/mod.rs

@@ -0,0 +1,27 @@
+use crate::prelude::*;
+use crate::untrusted::{
+    SliceAsMutPtrAndLen, SliceAsPtrAndLen, UntrustedSlice, UntrustedSliceAlloc,
+};
+use std;
+
+mod addr;
+mod any_addr;
+mod domain;
+mod flags;
+mod iovs;
+mod msg;
+mod protocol;
+mod shutdown;
+mod r#type;
+
+pub use self::addr::{
+    Addr, CSockAddr, Ipv4Addr, Ipv4SocketAddr, Ipv6SocketAddr, RawAddr, UnixAddr,
+};
+pub use self::any_addr::AnyAddr;
+pub use self::domain::Domain;
+pub use self::flags::{MsgFlags, RecvFlags, SendFlags};
+pub use self::iovs::{Iovs, IovsMut, SliceAsLibcIovec};
+pub use self::msg::{CMessages, CmsgData};
+pub use self::protocol::SocketProtocol;
+pub use self::r#type::Type;
+pub use self::shutdown::Shutdown;

src/libos/src/net/socket/util/msg.rs

@@ -0,0 +1,115 @@
+/// Socket message and its flags.
+use super::*;
+
+/// This struct is used to iterate through the control messages.
+///
+/// `cmsghdr` is a C struct for ancillary data object information of a unix socket.
+pub struct CMessages<'a> {
+    buffer: &'a [u8],
+    current: Option<&'a libc::cmsghdr>,
+}
+
+impl<'a> Iterator for CMessages<'a> {
+    type Item = CmsgData<'a>;
+
+    fn next(&mut self) -> Option<Self::Item> {
+        let cmsg = unsafe {
+            let mut msg: libc::msghdr = core::mem::zeroed();
+            msg.msg_control = self.buffer.as_ptr() as *mut _;
+            msg.msg_controllen = self.buffer.len() as _;
+
+            let cmsg = if let Some(current) = self.current {
+                libc::CMSG_NXTHDR(&msg, current)
+            } else {
+                libc::CMSG_FIRSTHDR(&msg)
+            };
+            cmsg.as_ref()?
+        };
+
+        self.current = Some(cmsg);
+        CmsgData::try_from_cmsghdr(cmsg)
+    }
+}
+
+impl<'a> CMessages<'a> {
+    pub fn from_bytes(msg_control: &'a mut [u8]) -> Self {
+        Self {
+            buffer: msg_control,
+            current: None,
+        }
+    }
+}
+
+/// Control message data of variable type. The data resides next to `cmsghdr`.
+pub enum CmsgData<'a> {
+    ScmRights(ScmRights<'a>),
+    ScmCredentials,
+}
+
+impl<'a> CmsgData<'a> {
+    /// Create an `CmsgData::ScmRights` variant.
+    ///
+    /// # Safety
+    ///
+    /// `data` must contain a valid control message and the control message must be type of
+    /// `SOL_SOCKET` and level of `SCM_RIGHTS`.
+    unsafe fn as_rights(data: &'a mut [u8]) -> Self {
+        let scm_rights = ScmRights { data };
+        CmsgData::ScmRights(scm_rights)
+    }
+
+    /// Create an `CmsgData::ScmCredentials` variant.
+    ///
+    /// # Safety
+    ///
+    /// `data` must contain a valid control message and the control message must be type of
+    /// `SOL_SOCKET` and level of `SCM_CREDENTIALS`.
+    unsafe fn as_credentials(_data: &'a [u8]) -> Self {
+        CmsgData::ScmCredentials
+    }
+
+    fn try_from_cmsghdr(cmsg: &'a libc::cmsghdr) -> Option<Self> {
+        unsafe {
+            let cmsg_len_zero = libc::CMSG_LEN(0) as usize;
+            let data_len = (*cmsg).cmsg_len as usize - cmsg_len_zero;
+            let data = libc::CMSG_DATA(cmsg);
+            let data = core::slice::from_raw_parts_mut(data, data_len);
+
+            match (*cmsg).cmsg_level {
+                libc::SOL_SOCKET => match (*cmsg).cmsg_type {
+                    libc::SCM_RIGHTS => Some(CmsgData::as_rights(data)),
+                    libc::SCM_CREDENTIALS => Some(CmsgData::as_credentials(data)),
+                    _ => None,
+                },
+                _ => None,
+            }
+        }
+    }
+}
+
+/// The data unit of this control message is file descriptor(s).
+///
+/// The level is equal to `SOL_SOCKET` and the type is equal to `SCM_RIGHTS`.
+pub struct ScmRights<'a> {
+    data: &'a mut [u8],
+}
+
+impl<'a> ScmRights<'a> {
+    /// Iterate and reassign each fd in data buffer, given a reassignment function.
+    pub fn iter_and_reassign_fds<F>(&mut self, reassign_fd_fn: F)
+    where
+        F: Fn(FileDesc) -> FileDesc,
+    {
+        for fd_bytes in self.data.chunks_exact_mut(core::mem::size_of::<FileDesc>()) {
+            let old_fd = FileDesc::from_ne_bytes(fd_bytes.try_into().unwrap());
+            let reassigned_fd = reassign_fd_fn(old_fd);
+            fd_bytes.copy_from_slice(&reassigned_fd.to_ne_bytes());
+        }
+    }
+
+    pub fn iter_fds(&self) -> impl Iterator<Item = FileDesc> + '_ {
+        self.data
+            .chunks_exact(core::mem::size_of::<FileDesc>())
+            .map(|fd_bytes| FileDesc::from_ne_bytes(fd_bytes.try_into().unwrap()))
+    }
+}

src/libos/src/net/socket/util/protocol.rs

@@ -0,0 +1,34 @@
+use num_enum::{IntoPrimitive, TryFromPrimitive};
+
+/* Standard well-defined IP protocols.  */
+#[allow(non_camel_case_types)]
+#[derive(Clone, Copy, Debug, Eq, PartialEq, IntoPrimitive, TryFromPrimitive)]
+#[repr(i32)]
+pub enum SocketProtocol {
+    IPPROTO_IP = 0,        /* Dummy protocol for TCP.  */
+    IPPROTO_ICMP = 1,      /* Internet Control Message Protocol.  */
+    IPPROTO_IGMP = 2,      /* Internet Group Management Protocol. */
+    IPPROTO_IPIP = 4,      /* IPIP tunnels (older KA9Q tunnels use 94).  */
+    IPPROTO_TCP = 6,       /* Transmission Control Protocol.  */
+    IPPROTO_EGP = 8,       /* Exterior Gateway Protocol.  */
+    IPPROTO_PUP = 12,      /* PUP protocol.  */
+    IPPROTO_UDP = 17,      /* User Datagram Protocol.  */
+    IPPROTO_IDP = 22,      /* XNS IDP protocol.  */
+    IPPROTO_TP = 29,       /* SO Transport Protocol Class 4.  */
+    IPPROTO_DCCP = 33,     /* Datagram Congestion Control Protocol.  */
+    IPPROTO_IPV6 = 41,     /* IPv6 header.  */
+    IPPROTO_RSVP = 46,     /* Reservation Protocol.  */
+    IPPROTO_GRE = 47,      /* General Routing Encapsulation.  */
+    IPPROTO_ESP = 50,      /* encapsulating security payload.  */
+    IPPROTO_AH = 51,       /* authentication header.  */
+    IPPROTO_MTP = 92,      /* Multicast Transport Protocol.  */
+    IPPROTO_BEETPH = 94,   /* IP option pseudo header for BEET.  */
+    IPPROTO_ENCAP = 98,    /* Encapsulation Header.  */
+    IPPROTO_PIM = 103,     /* Protocol Independent Multicast.  */
+    IPPROTO_COMP = 108,    /* Compression Header Protocol.  */
+    IPPROTO_SCTP = 132,    /* Stream Control Transmission Protocol.  */
+    IPPROTO_UDPLITE = 136, /* UDP-Lite protocol.  */
+    IPPROTO_MPLS = 137,    /* MPLS in IP.  */
+    IPPROTO_RAW = 255,     /* Raw IP packets.  */
+    IPPROTO_MAX,
+}

src/libos/src/net/socket/util/shutdown.rs

@@ -0,0 +1,34 @@
+use crate::prelude::*;
+
+#[derive(Clone, Copy, Debug, PartialEq, Eq)]
+#[repr(u32)]
+pub enum Shutdown {
+    Read = 0,
+    Write = 1,
+    Both = 2,
+}
+
+impl Shutdown {
+    pub fn from_c(c_val: u32) -> Result<Self> {
+        match c_val {
+            0 => Ok(Self::Read),
+            1 => Ok(Self::Write),
+            2 => Ok(Self::Both),
+            _ => return_errno!(EINVAL, "invalid how"),
+        }
+    }
+
+    pub fn to_c(&self) -> u32 {
+        *self as u32
+    }
+
+    pub fn should_shut_read(&self) -> bool {
+        // a slightly more efficient check than using two equality comparions
+        self.to_c() % 2 == 0
+    }
+
+    pub fn should_shut_write(&self) -> bool {
+        // a slightly more efficient check than using two equality comparions
+        self.to_c() >= 1
+    }
+}

src/libos/src/net/socket/util/type.rs

@@ -0,0 +1,15 @@
+use crate::prelude::*;
+use num_enum::{IntoPrimitive, TryFromPrimitive};
+
+/// A network type.
+#[derive(Clone, Copy, Debug, Eq, PartialEq, IntoPrimitive, TryFromPrimitive)]
+#[repr(i32)]
+pub enum Type {
+    STREAM = libc::SOCK_STREAM,
+    DGRAM = libc::SOCK_DGRAM,
+    RAW = libc::SOCK_RAW,
+    RDM = libc::SOCK_RDM,
+    SEQPACKET = libc::SOCK_SEQPACKET,
+    DCCP = libc::SOCK_DCCP,
+    PACKET = libc::SOCK_PACKET,
+}