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use std::str::FromStr;
use std::sync::Arc;
use std::sync::atomic::{AtomicBool, Ordering};
use async_std::{io, task};
use async_std::prelude::*;
use async_trait::async_trait;
use async_std::net::{TcpListener, TcpStream};
use log::{debug, error, info, trace};
use crate::protocol::{FtlCommand, FtlError, FtlHandshake, FtlHandshakeFinalised, FtlResponse};
use crate::util;
pub struct IngestClient {
channel_id: Option<String>,
hmac_payload: String,
handshake: FtlHandshake,
should_stop: Arc<AtomicBool>
}
#[async_trait]
pub trait IngestServer {
async fn launch(&'static self, addr: String) -> Result<(), io::Error> {
let listener = TcpListener::bind(addr).await?;
while let Ok((stream, address)) = listener.accept().await {
info!("Remote client connected: {}", address);
task::spawn(async move {
let (reader, writer) = &mut (&stream, &stream);
let mut client = IngestClient {
channel_id: None,
hmac_payload: util::generate_hmac(),
handshake: FtlHandshake::default(),
should_stop: Arc::new(AtomicBool::new(false)),
};
let mut reader = reader.bytes();
let mut buffer = Vec::with_capacity(128);
while let Some(byte) = reader.next().await {
if let Ok(byte) = byte {
match byte {
b'\n' => {
if buffer.len() > 0 {
if let Ok(payload) = std::str::from_utf8(&buffer) {
if let Ok(command) = FtlCommand::from_str(payload) {
if let Err(error) = self.handler(&mut client, writer, command).await {
if error.is_err() {
error!("Failed to execute FTL command. {:?}", error);
}
writer.write(
error
.to_string()
.as_bytes()
)
.await
.ok();
break;
}
} else {
error!("Failed to deserialise FTL command. {}", payload);
}
} else {
error!("Failed to convert buffer to UTF8 string.");
}
buffer.clear();
}
}
b'\r' => continue,
byte => buffer.push(byte)
}
} else {
error!("Failed to read anymore bytes from client.");
break;
}
}
info!("Remote FTL client disconnected.");
client.should_stop.store(true, Ordering::Relaxed);
stream.shutdown(std::net::Shutdown::Both).ok();
});
}
Ok(())
}
async fn handler(&self, client: &mut IngestClient, mut writer: &TcpStream, command: FtlCommand) -> Result<(), FtlError> {
match command {
FtlCommand::HMAC => {
debug!("Client requested HMAC payload, sending response.");
writer.write(
FtlResponse::HMAC {
hmac_payload: client.hmac_payload.clone()
}
.to_string()
.as_bytes()
)
.await
.map_err(|_| FtlError::IoError)?;
Ok(())
}
FtlCommand::Connect { channel_id, hashed_hmac_payload } => {
debug!("Client is connecting, attempting to stream to {}.", &channel_id);
let known_key = self.get_stream_key(&channel_id)
.await.map_err(|_| FtlError::InvalidStreamKey)?;
let client_hash = hex::decode(hashed_hmac_payload[1..].to_string())
.map_err(|_| FtlError::DecodeError)?;
let key = ring::hmac::Key::new(ring::hmac::HMAC_SHA512, &known_key.as_bytes());
ring::hmac::verify(
&key,
&hex::decode(client.hmac_payload.clone().into_bytes())
.map_err(|_| FtlError::DecodeError)?,
&client_hash.as_slice()
).map_err(|_| FtlError::RingError)?;
debug!("Client was verified, ready to stream to {}.", &channel_id);
client.channel_id = Some(channel_id);
writer.write(
FtlResponse::Success
.to_string()
.as_bytes()
)
.await
.map_err(|_| FtlError::IoError)?;
Ok(())
}
FtlCommand::Attribute { key, value } => client.handshake.insert(key, value),
FtlCommand::Dot => {
if let Some(channel_id) = &client.channel_id {
let handshake = client.handshake.clone().finalise()?;
let udp_port = self.allocate_ingest(channel_id, handshake, client.should_stop.clone())
.await.map_err(|_| FtlError::AllocateError)?;
debug!("Client is about to begin stream. Allocated port {}.", udp_port);
writer.write(
FtlResponse::Connect { udp_port }
.to_string()
.as_bytes()
)
.await
.map_err(|_| FtlError::IoError)?;
Ok(())
} else {
Err(FtlError::InvalidStreamKey)
}
}
FtlCommand::Ping { channel_id } => {
trace!("Client sent ping. {}", &channel_id);
writer.write(
FtlResponse::Pong
.to_string()
.as_bytes()
)
.await
.map_err(|_| FtlError::IoError)?;
Ok(())
}
FtlCommand::Disconnect => Err(FtlError::Disconnect)
}
}
async fn get_stream_key(&self, channel_id: &str) -> Result<String, ()>;
async fn allocate_ingest(&self, channel_id: &str, handshake: FtlHandshakeFinalised, should_stop: Arc<AtomicBool>) -> Result<u16, ()>;
}
