Initial commit

tun/src/apple/kern_control.rs

@@ -0,0 +1,53 @@
+use libc::{sockaddr_ctl, AF_SYSTEM, AF_SYS_CONTROL};
+use std::io::Result;
+use std::mem::size_of;
+use std::os::unix::io::AsRawFd;
+
+/// Trait to connect to kernel extensions on Apple platforms
+///
+/// Pulled from XNU source: https://github.com/apple/darwin-xnu/blob/main/bsd/sys/kern_control.h
+pub trait SysControlSocket {
+    fn resolve(&self, name: &str, index: u32) -> Result<socket2::SockAddr>;
+}
+
+impl SysControlSocket for socket2::Socket {
+    fn resolve(&self, name: &str, index: u32) -> Result<socket2::SockAddr> {
+        let mut info = sys::ctl_info {
+            ctl_id: 0,
+            ctl_name: [0; 96],
+        };
+        info.ctl_name[..name.len()].copy_from_slice(name.as_bytes());
+
+        unsafe { sys::resolve_ctl_info(self.as_raw_fd(), &mut info as *mut sys::ctl_info)? };
+
+        let (_, addr) = unsafe {
+            socket2::SockAddr::init(|addr_storage, len| {
+                *len = size_of::<sockaddr_ctl>() as u32;
+
+                let mut addr: &mut sockaddr_ctl = &mut *addr_storage.cast();
+                addr.sc_len = *len as u8;
+                addr.sc_family = AF_SYSTEM as u8;
+                addr.ss_sysaddr = AF_SYS_CONTROL as u16;
+                addr.sc_id = info.ctl_id;
+                addr.sc_unit = index;
+                Ok(())
+            })
+        }?;
+
+        Ok(addr)
+    }
+}
+
+mod sys {
+    use nix::ioctl_readwrite;
+
+    const MAX_KCTL_NAME: usize = 96;
+
+    #[repr(C)]
+    pub struct ctl_info {
+        pub ctl_id: u32,
+        pub ctl_name: [u8; MAX_KCTL_NAME],
+    }
+
+    ioctl_readwrite!(resolve_ctl_info, b'N', 3, ctl_info);
+}