devices/vsock/tsi: fix parse_address on macOS

The method parse_address generates a SockaddrStorage object from raw
socket information from the Linux guest. This doesn't work on macOS
because both sockaddr-related structs and definitions differ from Linux.

Fix it by manually parsing the address data on macOS. We leave AF_UNIX
support for later, since nix doesn't have a way to cast UnixPath to
SockaddrStorage.

Signed-off-by: Sergio Lopez <[email protected]>

Author: slp

src/devices/src/virtio/vsock/mod.rs

@@ -59,6 +59,11 @@ mod defs {
     pub const TSI_ACCEPT: u32 = 1030;
     pub const TSI_PROXY_RELEASE: u32 = 1031;
 
+    // Linux definitions that we need for cross-platform compatibility.
+    pub const LINUX_AF_UNIX: u16 = 1;
+    pub const LINUX_AF_INET: u16 = 2;
+    pub const LINUX_AF_INET6: u16 = 10;
+
     pub mod uapi {
 
         /// Virtio feature flags.

src/devices/src/virtio/vsock/packet.rs

@@ -18,10 +18,14 @@
 use std::convert::TryInto;
 use std::ffi::CStr;
 use std::net::{Ipv4Addr, SocketAddrV4};
+#[cfg(target_os = "macos")]
+use std::net::{Ipv6Addr, SocketAddrV6};
 use std::os::raw::c_char;
 use std::result;
 
-use nix::sys::socket::{sockaddr, AddressFamily, SockaddrLike, SockaddrStorage};
+#[cfg(target_os = "linux")]
+use nix::sys::socket::{sockaddr, AddressFamily};
+use nix::sys::socket::{SockaddrLike, SockaddrStorage};
 use utils::byte_order;
 use vm_memory::{self, Address, GuestAddress, GuestMemory, GuestMemoryError};
 
@@ -480,6 +484,7 @@ impl VsockPacket {
         }
     }
 
+    #[cfg(target_os = "linux")]
     fn parse_address(buf: &[u8], addr_len: u32) -> Option<SockaddrStorage> {
         let sockaddr: SockaddrStorage = unsafe {
             SockaddrStorage::from_raw(&buf[0] as *const _ as *const sockaddr, Some(addr_len))?
@@ -502,6 +507,44 @@ impl VsockPacket {
         Some(sockaddr)
     }
 
+    #[cfg(target_os = "macos")]
+    fn parse_address(buf: &[u8], _addr_len: u32) -> Option<SockaddrStorage> {
+        let family: u16 = byte_order::read_le_u16(&buf[0..2]);
+
+        match family {
+            defs::LINUX_AF_INET => {
+                debug!("parse_address: AF_INET");
+                let in_port: u16 = byte_order::read_be_u16(&buf[2..4]);
+                let in_addr = Ipv4Addr::new(buf[4], buf[5], buf[6], buf[7]);
+                Some(SocketAddrV4::new(in_addr, in_port).into())
+            }
+            defs::LINUX_AF_INET6 => {
+                debug!("parse_address: AF_INET6");
+                let in_port: u16 = byte_order::read_be_u16(&buf[2..4]);
+                let flowinfo: u32 = byte_order::read_be_u32(&buf[4..8]);
+                let in6_addr = Ipv6Addr::new(
+                    byte_order::read_be_u16(&buf[8..10]),
+                    byte_order::read_be_u16(&buf[10..12]),
+                    byte_order::read_be_u16(&buf[12..14]),
+                    byte_order::read_be_u16(&buf[14..16]),
+                    byte_order::read_be_u16(&buf[16..18]),
+                    byte_order::read_be_u16(&buf[18..20]),
+                    byte_order::read_be_u16(&buf[20..22]),
+                    byte_order::read_be_u16(&buf[22..24]),
+                );
+                let scope_id: u32 = byte_order::read_be_u32(&buf[24..28]);
+                Some(SocketAddrV6::new(in6_addr, in_port, flowinfo, scope_id).into())
+            }
+            defs::LINUX_AF_UNIX => {
+                // On macOS, SockaddrStorage doesn't implement `from_raw` for
+                // Unix sockets, nor a way to cast an UnixPath to it.
+                error!("AF_UNIX sockets aren't yet supported on macOS");
+                None
+            }
+            _ => None,
+        }
+    }
+
     pub fn read_proxy_create(&self) -> Option<TsiProxyCreate> {
         if self.buf_size >= 6 {
             let peer_port: u32 = byte_order::read_le_u32(&self.buf().unwrap()[0..]);

src/devices/src/virtio/vsock/tsi_dgram.rs

@@ -5,7 +5,6 @@ use std::os::fd::OwnedFd;
 use std::os::unix::io::{AsRawFd, RawFd};
 use std::sync::{Arc, Mutex};
 
-use libc::{AF_INET, AF_INET6, AF_UNIX};
 use nix::fcntl::{fcntl, FcntlArg, OFlag};
 use nix::sys::socket::{
     bind, connect, getpeername, recv, send, sendto, socket, AddressFamily, MsgFlags, SockFlag,
@@ -55,10 +54,11 @@ impl TsiDgramProxy {
         queue: Arc<Mutex<VirtQueue>>,
         rxq: Arc<Mutex<MuxerRxQ>>,
     ) -> Result<Self, ProxyError> {
-        let family = match family as i32 {
-            AF_INET => AddressFamily::Inet,
-            AF_INET6 => AddressFamily::Inet6,
-            AF_UNIX => AddressFamily::Unix,
+        let family = match family {
+            defs::LINUX_AF_INET => AddressFamily::Inet,
+            defs::LINUX_AF_INET6 => AddressFamily::Inet6,
+            #[cfg(target_os = "linux")]
+            defs::LINUX_AF_UNIX => AddressFamily::Unix,
             _ => return Err(ProxyError::InvalidFamily),
         };
 

src/devices/src/virtio/vsock/tsi_stream.rs

@@ -13,7 +13,6 @@ use std::sync::{Arc, Mutex};
 use libc::EINVAL;
 #[cfg(target_os = "macos")]
 use libc::EINVAL;
-use libc::{AF_INET, AF_INET6, AF_UNIX};
 use nix::errno::Errno;
 use nix::fcntl::{fcntl, FcntlArg, OFlag};
 use nix::sys::socket::{
@@ -74,10 +73,11 @@ impl TsiStreamProxy {
         queue: Arc<Mutex<VirtQueue>>,
         rxq: Arc<Mutex<MuxerRxQ>>,
     ) -> Result<Self, ProxyError> {
-        let family = match family as i32 {
-            AF_INET => AddressFamily::Inet,
-            AF_INET6 => AddressFamily::Inet6,
-            AF_UNIX => AddressFamily::Unix,
+        let family = match family {
+            defs::LINUX_AF_INET => AddressFamily::Inet,
+            defs::LINUX_AF_INET6 => AddressFamily::Inet6,
+            #[cfg(target_os = "linux")]
+            defs::LINUX_AF_UNIX => AddressFamily::Unix,
             _ => return Err(ProxyError::InvalidFamily),
         };
         let fd = socket(family, SockType::Stream, SockFlag::empty(), None)