alnyan/yggdrasil: Add LookupHost and TimerFd

library/std/src/os/yggdrasil/io/mod.rs

@@ -12,6 +12,7 @@ pub mod pipe;
 pub mod poll;
 pub mod shared_memory;
 pub mod terminal;
+pub mod timer;
 
 // Public exports
 

library/std/src/os/yggdrasil/io/timer.rs

@@ -0,0 +1,34 @@
+#![unstable(feature = "yggdrasil_os", issue = "none")]
+
+use crate::io;
+use crate::os::fd::{AsRawFd, FromRawFd, RawFd};
+use crate::sys::cvt_io;
+use crate::sys::fd::FileDesc;
+use crate::time::Duration;
+
+use yggdrasil_rt::sys as syscall;
+
+#[unstable(feature = "yggdrasil_os", issue = "none")]
+pub struct TimerFd(FileDesc);
+
+impl TimerFd {
+    #[unstable(feature = "yggdrasil_os", issue = "none")]
+    pub fn new(repeat: bool) -> io::Result<Self> {
+        let raw = cvt_io(unsafe { syscall::create_timer(repeat) })?;
+        let fd = unsafe { FileDesc::from_raw_fd(raw) };
+        Ok(Self(fd))
+    }
+
+    pub fn start(&mut self, timeout: Duration) -> io::Result<()> {
+        let tval = timeout.as_micros();
+        cvt_io(unsafe { syscall::write(self.0.as_raw_fd(), &tval.to_ne_bytes()) })?;
+        Ok(())
+    }
+}
+
+#[unstable(feature = "yggdrasil_os", issue = "none")]
+impl AsRawFd for TimerFd {
+    fn as_raw_fd(&self) -> RawFd {
+        self.0.as_raw_fd()
+    }
+}

library/std/src/sys/yggdrasil/net/dns.rs

@@ -0,0 +1,145 @@
+use yggdrasil_rt::net::dns::{
+    self, DnsClass, DnsMessage, DnsRecordData, DnsReplyCode, DnsType, UdpRequester,
+};
+
+use crate::io;
+use crate::net::{IpAddr, Ipv4Addr, SocketAddr, UdpSocket};
+use crate::os::{
+    fd::AsRawFd,
+    yggdrasil::io::{poll::PollChannel, timer::TimerFd},
+};
+use crate::time::Duration;
+
+pub struct LookupHost {
+    addresses: Vec<IpAddr>,
+    port: u16,
+}
+
+struct DnsRequester {
+    nameserver: SocketAddr,
+
+    poll: PollChannel,
+
+    timer: TimerFd,
+    socket: UdpSocket,
+}
+
+// TODO remove hardcoded nameserver
+//      Maybe use local resolver?
+const NAMESERVER: SocketAddr = SocketAddr::new(IpAddr::V4(Ipv4Addr::new(11, 0, 0, 1)), 53);
+
+impl DnsRequester {
+    pub fn new(nameserver: SocketAddr) -> io::Result<Self> {
+        let mut poll = PollChannel::new()?;
+        let timer = TimerFd::new(false)?;
+        let socket = UdpSocket::bind("0.0.0.0:0")?;
+
+        poll.add(timer.as_raw_fd())?;
+        poll.add(socket.as_raw_fd())?;
+
+        Ok(Self { nameserver, poll, timer, socket })
+    }
+}
+
+impl UdpRequester for DnsRequester {
+    type Error = io::Error;
+
+    fn send_message(&mut self, message: &[u8]) -> io::Result<()> {
+        self.socket.send_to(message, &self.nameserver)?;
+        Ok(())
+    }
+
+    fn receive_message<F: Fn(&[u8]) -> Option<DnsMessage>>(
+        &mut self,
+        map: F,
+    ) -> io::Result<DnsMessage> {
+        let mut buffer = [0; 2048];
+
+        self.timer.start(Duration::from_millis(500));
+
+        loop {
+            let (poll_fd, result) = self.poll.wait(None)?.unwrap();
+            result?;
+
+            match poll_fd {
+                fd if fd == self.socket.as_raw_fd() => {
+                    let (len, _) = self.socket.recv_from(&mut buffer)?;
+
+                    if let Some(message) = map(&buffer[..len]) {
+                        return Ok(message);
+                    }
+                }
+                fd if fd == self.timer.as_raw_fd() => {
+                    return Err(io::Error::new(io::ErrorKind::TimedOut, "DNS query timed out"));
+                }
+                _ => unreachable!(),
+            }
+        }
+    }
+}
+
+impl LookupHost {
+    pub fn port(&self) -> u16 {
+        self.port
+    }
+}
+
+impl Iterator for LookupHost {
+    type Item = SocketAddr;
+
+    fn next(&mut self) -> Option<SocketAddr> {
+        let ip = self.addresses.pop()?;
+        Some(SocketAddr::new(ip, self.port))
+    }
+}
+
+impl TryFrom<&str> for LookupHost {
+    type Error = io::Error;
+
+    fn try_from(s: &str) -> io::Result<Self> {
+        use crate::str::FromStr;
+
+        let (hostname, port) = s
+            .rsplit_once(':')
+            .ok_or(io::Error::new(io::ErrorKind::InvalidData, "Invalid host:port combination"))?;
+        let port =
+            u16::from_str(port).map_err(|e| io::Error::new(io::ErrorKind::InvalidData, e))?;
+
+        Self::try_from((hostname, port))
+    }
+}
+
+impl<'a> TryFrom<(&'a str, u16)> for LookupHost {
+    type Error = io::Error;
+
+    fn try_from((hostname, port): (&'a str, u16)) -> io::Result<Self> {
+        // TODO randomize xid/cookie
+        let mut requester = DnsRequester::new(NAMESERVER)?;
+        let message = dns::perform_query(&mut requester, hostname, DnsType::A, 12341, 0x12313121)?;
+
+        if message.reply_code != DnsReplyCode::NO_ERROR {
+            return Err(io::Error::new(io::ErrorKind::Other, "DNS server returned error"));
+        }
+
+        let mut addresses = vec![];
+
+        for answer in message.answers {
+            let Some(name) = answer.name.0.as_ref() else {
+                continue;
+            };
+            let name = name.trim_end_matches('.');
+            if name != hostname {
+                continue;
+            }
+
+            match (answer.ty, answer.class, &answer.rdata) {
+                (DnsType::A, DnsClass::IN, DnsRecordData::A(address)) => {
+                    addresses.push(IpAddr::V4(u32::from(*address).into()));
+                }
+                _ => (),
+            }
+        }
+
+        Ok(Self { addresses, port })
+    }
+}

library/std/src/sys/yggdrasil/net/mod.rs

@@ -1,58 +1,15 @@
 #![allow(dead_code)]
 
-// use crate::io::{self, BorrowedCursor, IoSlice, IoSliceMut};
-// use crate::net::{Ipv4Addr, Ipv6Addr, Shutdown, SocketAddr};
-// use crate::os::yggdrasil::io::{AsFd, AsRawFd, BorrowedFd, RawFd};
-// use crate::sys::io::FileDesc;
-// use crate::sys_common::{AsInner, FromInner, IntoInner};
-// use crate::time::Duration;
-//
-// pub use crate::sys::{cvt, cvt_r};
-
-// pub use super::yggdrasil_rt::netc;
-
+mod dns;
 mod tcp_listener;
 mod tcp_stream;
 mod udp;
 
+pub use dns::LookupHost;
 pub use tcp_listener::TcpListener;
 pub use tcp_stream::TcpStream;
 pub use udp::UdpSocket;
 
-use crate::net::SocketAddr;
-
-pub struct LookupHost(!);
-
-impl LookupHost {
-    pub fn port(&self) -> u16 {
-        todo!()
-    }
-}
-
-impl Iterator for LookupHost {
-    type Item = SocketAddr;
-
-    fn next(&mut self) -> Option<SocketAddr> {
-        todo!()
-    }
-}
-
-impl TryFrom<&str> for LookupHost {
-    type Error = crate::io::Error;
-
-    fn try_from(_s: &str) -> crate::io::Result<Self> {
-        todo!()
-    }
-}
-
-impl<'a> TryFrom<(&'a str, u16)> for LookupHost {
-    type Error = crate::io::Error;
-
-    fn try_from(_s: (&'a str, u16)) -> crate::io::Result<Self> {
-        todo!()
-    }
-}
-
 // pub type wrlen_t = usize;
 
 // #[derive(Debug)]