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use super::*;
use tokio::io::{AsyncWrite, AsyncRead};
use std::sync::Arc;
use openssl::symm::Crypter;
use crypt::{
RsaPublicKey,
RsaPrivateKey,
};
/// A type that implements both `AsyncWrite` and `AsyncRead`
pub trait AsyncStream: AsyncRead + AsyncWrite{}
impl<T: AsyncRead + AsyncWrite + ?Sized> AsyncStream for T{}
/// Inner rsa data for encrypted stream read+write halves
struct EncryptedStreamMeta
{
us: RsaPrivateKey,
them: Option<RsaPublicKey>,
}
/// Writable half of `EncryptedStream`.
pub struct WriteHalf<S>
where S: AsyncWrite
{
meta: Arc<EncryptedStreamMeta>,
backing_write: Box<dual::DualStream<S>>,
}
/// Readable half of `EncryptedStream`.
pub struct ReadHalf<S>
where S: AsyncRead
{
meta: Arc<EncryptedStreamMeta>,
/// chacha20_poly1305 decrypter for incoming reads from `S`
//TODO: chacha20stream: implement a read version of AsyncSink so we don't need to keep this?
cipher: Option<Crypter>,
backing_read: Box<S>,
}
struct ReadWriteCombined<R, W>
{
/// Since chacha20stream has no AsyncRead counterpart, we have to do it ourselves.
cipher_read: Option<Crypter>,
backing_read: R,
backing_write: dual::DualStream<W>,
}
/// RSA/chacha20 encrypted stream
pub struct EncryptedStream<R, W>
where R: AsyncRead,
W: AsyncWrite,
{
meta: EncryptedStreamMeta,
// Keep the streams on the heap to keep this type not hueg.
backing: Box<ReadWriteCombined<R, W>>,
}
//TODO: How do we use this with a single AsyncStream instead of requiring 2? Will we need to make our own Arc wrapper?? Ugh,, for now let's ignore this I guess... Most read+write thingies have a Read/WriteHalf split mechanism.
impl<R: AsyncRead, W: AsyncWrite> EncryptedStream<R, W>
{
/// Has this stream done its RSA key exchange?
pub fn has_exchanged(&self) -> bool
{
self.meta.them.is_some()
}
/// Split this stream into a read and writeable half.
pub fn split(self) -> (WriteHalf<W>, ReadHalf<R>)
{
let meta = Arc::new(self.meta);
let (read, write) = {
let ReadWriteCombined { cipher_read, backing_read, backing_write } = *self.backing;
((cipher_read, backing_read), backing_write)
};
(WriteHalf {
meta: Arc::clone(&meta),
backing_write: Box::new(write),
}, ReadHalf {
meta,
cipher: read.0,
backing_read: Box::new(read.1),
})
}
/// Join a split `EncryptedStream` from halves.
///
/// # Panics
/// If the read and write half are not from the same split.
pub fn from_split((write, read): (WriteHalf<W>, ReadHalf<R>)) -> Self
{
if !Arc::ptr_eq(&write.meta, &read.meta) {
panic!("Read and Write halves are not from the same split");
}
todo!("Drop write's `meta`, consume read's `meta`. Move the streams into `ReadWriteCombined`")
}
}