barentp 1.3.0

An NTP client library for use with and without the standard library.
Documentation 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62

use crate::{
    error::Error,
    protocol::{SntpMessage, Timestamp},
};
use core::future::Future;

pub trait NtpTransportAsync {
    type SendError;
    type RecvError;

    fn send(&self, buffer: &[u8]) -> impl Future<Output = Result<(), Self::SendError>> + Send;
    fn recv(
        &self,
        buffer: &mut [u8],
    ) -> impl Future<Output = Result<usize, Self::RecvError>> + Send;
}

async fn sntp_send_and_recv<T>(
    transport: &T,
) -> Result<SntpMessage, Error<T::SendError, T::RecvError>>
where
    T: NtpTransportAsync,
{
    let mut buf = [0; SntpMessage::BUFFER_SIZE];
    let mut msg = SntpMessage::new_v4();
    msg.write_to_buffer(&mut buf)?;
    transport.send(&buf).await.map_err(Error::TransportSend)?;
    transport
        .recv(&mut buf)
        .await
        .map_err(Error::TransportRecv)?;
    msg.read_from_buffer(&buf)?;
    Ok(msg)
}

pub async fn sntp_get_transmit_timestamp<T>(
    transport: &T,
) -> Result<Timestamp, Error<T::SendError, T::RecvError>>
where
    T: NtpTransportAsync,
{
    let msg = sntp_send_and_recv(transport).await?;
    Ok(msg.transmit_timestamp)
}

#[cfg(feature = "std")]
impl NtpTransportAsync for std::net::UdpSocket {
    type SendError = std::io::Error;
    type RecvError = std::io::Error;

    async fn send(&self, mut buffer: &[u8]) -> Result<(), Self::SendError> {
        while !buffer.is_empty() {
            let sent = self.send(buffer)?;
            buffer = &buffer[sent..];
        }
        Ok(())
    }

    async fn recv(&self, buffer: &mut [u8]) -> Result<usize, Self::RecvError> {
        self.recv(buffer)
    }
}