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use std::{collections::HashMap, error::Error, fmt, io::ErrorKind, net::SocketAddr, sync::Arc, time::Duration};
use plain_binary_stream::{BinaryStream, Serializable};
use tokio::{io::{AsyncReadExt, AsyncWriteExt}, net::{TcpListener, TcpStream, tcp::ReadHalf}, sync::{mpsc, Mutex}, time::timeout};
use crate::{AM, BantamPacketType, ByePacket, DataPacket, HandshakePacket, HandshakeResponsePacket, PacketHeader, SerializableSocketAddr};
pub const TCP_STREAM_READ_BUFFER_SIZE: usize = 256;
pub const TCP_STREAM_CONNECTION_TIMEOUT_SECS: u64 = 15;
pub const TCP_STREAM_READ_TIMEOUT_SECS: u64 = 5;
type Tx = mpsc::UnboundedSender<Vec<u8>>;
#[derive(Debug)]
pub enum BantamError {
ConnectionTimeout,
ReadTimeout,
ReceivedCorruptedPacket
}
impl fmt::Display for BantamError {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
write!(f, "{}", self.to_string())
}
}
impl Error for BantamError {
fn source(&self) -> Option<&(dyn Error + 'static)> {
None
}
fn description(&self) -> &str {
"description() is deprecated; use Display"
}
fn cause(&self) -> Option<&dyn Error> {
None
}
}
pub struct Peer {
pub listener_addr: SocketAddr,
sender: Tx
}
pub trait ExternalSharedState {
fn on_connected(&mut self, addr: SocketAddr);
fn on_disconnected(&mut self, addr: SocketAddr);
fn on_receive_packet(&mut self, bytes: Vec<u8>, sender_addr: SocketAddr);
}
pub struct PeerSharedState {
listener_addr: SocketAddr,
peers: HashMap<SocketAddr, Peer>
}
impl PeerSharedState {
pub fn get_peers(&self) -> Vec<(&SocketAddr, &Peer)> {
let peers = self.peers.iter().map(|pair| {
(pair.0, pair.1)
}).collect();
peers
}
pub fn get_peer_count(&self) -> usize {
return self.peers.len()
}
fn add_peer(&mut self, addr: SocketAddr, peer: Peer) -> bool {
self.peers.insert(addr, peer).is_none()
}
fn remove_peer(&mut self, addr: SocketAddr) -> bool {
self.peers.remove(&addr).is_some()
}
async fn broadcast(&self, bytes: Vec<u8>) -> Result<(), Box<dyn Error + Send + Sync>> {
Ok(for peer in self.peers.iter() {
peer.1.sender.send(bytes.clone())?
})
}
async fn unicast(&mut self, bytes: Vec<u8>, addr: SocketAddr) -> Result<(), Box<dyn Error + Send + Sync>> {
if let Some(peer) = self.peers.get(&addr) {
peer.sender.send(bytes)?;
}
else {
eprintln!("Peer with address {} is not part of this network.", addr);
}
Ok(())
}
}
pub async fn setup_peer<T: ExternalSharedState + Send + Sync + 'static>(port: u16, addr: SocketAddr,
ext_shared_state: AM<T>) -> Result<AM<PeerSharedState>, Box<dyn Error + Send + Sync>> {
let shared_state = setup_ingoing_peer(port, ext_shared_state.clone()).await?;
let shared_state_ref = shared_state.clone();
setup_outgoing_peer(addr, shared_state, true, ext_shared_state.clone()).await?;
Ok(shared_state_ref)
}
pub async fn setup_ingoing_peer<T: ExternalSharedState + Send + Sync + 'static>(port: u16,
ext_shared_state: AM<T>) -> Result<AM<PeerSharedState>, Box<dyn Error + Send + Sync>> {
let listener_addr: SocketAddr = format!("0.0.0.0:{}", port).parse().unwrap();
let listener = TcpListener::bind(listener_addr).await?;
let shared_state = Arc::new(Mutex::new(PeerSharedState {
listener_addr: listener_addr,
peers: HashMap::new()
}));
let shared_state_ref = shared_state.clone();
tokio::spawn(async move {
loop {
match listener.accept().await {
Ok((conn, addr)) => {
let shared_state_conn = shared_state.clone();
println!("Accepted connection with {}...", &addr);
handle_peer(conn, addr, shared_state_conn, ext_shared_state.clone())
},
Err(e) => {
eprintln!("Failed to accept new connection: {}.", e);
break;
}
}
}
println!("Terminating listener loop. Ingoing peer shut down.")
});
Ok(shared_state_ref)
}
async fn setup_outgoing_peer<T: ExternalSharedState + Send + Sync + 'static>(addr: SocketAddr,
shared_state: AM<PeerSharedState>, request_peers: bool, ext_shared_state: AM<T>) -> Result<(), Box<dyn Error + Send + Sync>> {
match timeout(Duration::from_secs(TCP_STREAM_CONNECTION_TIMEOUT_SECS),
TcpStream::connect(addr)).await {
Ok(connection_result) => {
match connection_result {
Ok(mut conn) => {
conn.write_all(&construct_bantam_packet(HandshakePacket::new(
shared_state.lock().await.listener_addr.port(), request_peers))).await?;
println!("Connecting with {}...", &addr);
handle_peer(conn, addr, shared_state.clone(), ext_shared_state);
Ok(())
},
Err(e) => return Err(Box::new(e))
}
},
Err(_) => {
return Err(Box::new(BantamError::ConnectionTimeout));
}
}
}
pub async fn shutdown(shared_state: AM<PeerSharedState>) -> Result<(), Box<dyn Error + Send + Sync>> {
send_bantam_packet(ByePacket::new(0), shared_state).await
}
fn handle_peer<T: ExternalSharedState + Send + Sync + 'static>(conn: TcpStream, addr: SocketAddr,
shared_state: AM<PeerSharedState>, ext_shared_state: AM<T>) {
if let Err(e) = conn.set_linger(None) {
println!("Failed to set linger duration of connection with {}: {}.", addr, e);
}
if let Err(e) = conn.set_nodelay(true) {
println!("Failed to set no delay of connection with {}: {}.", addr, e);
}
tokio::spawn(async move {
if let Err(e) = handle_peer_io_loop(conn, addr, shared_state, ext_shared_state).await {
eprintln!("Failed running IO loop for {}: {}", addr, e);
}
});
}
async fn handle_peer_io_loop<T: ExternalSharedState + Send + Sync + 'static>(mut conn: TcpStream, addr: SocketAddr,
shared_state: AM<PeerSharedState>, ext_shared_state: AM<T>) -> Result<(), Box<dyn Error + Send + Sync>> {
let (tx, mut rx) = mpsc::unbounded_channel::<Vec<u8>>();
let (mut reader, mut writer) = conn.split();
loop {
let mut buffer = [0u8; TCP_STREAM_READ_BUFFER_SIZE];
tokio::select! {
Some(msg) = rx.recv() => {
writer.write_all(&msg).await?;
}
read_result = reader.read(&mut buffer) => match read_result {
Ok(bytes_received) => {
let mut buffer_vec = buffer[0..bytes_received].to_vec();
match read_segments(bytes_received, &mut buffer_vec, &mut reader).await {
Err(e) => {
eprintln!("Error occured while reading packet segments of {}: {}", addr, e);
break;
},
Ok(total_bytes_received) if total_bytes_received == 0 => break,
_ => ()
}
match process_packet(buffer_vec, addr, tx.clone(), shared_state.clone(), ext_shared_state.clone()).await {
Ok(connected) if !connected => break,
Err(e) => {
eprintln!("Error occured while processing received packet: {}.", e);
break
},
_ => ()
}
},
Err(e) if e.kind() == ErrorKind::ConnectionReset => break,
Err(e) => {
eprintln!("Error ({:?}) occured while reading stream of {}: {}", e.kind(), &addr, e);
break
}
}
}
}
println!("Peer {} disconnected.", &addr);
ext_shared_state.lock().await.on_disconnected(addr);
shared_state.lock().await.remove_peer(addr);
Ok(())
}
async fn read_segments<'a>(bytes_received: usize, buffer_vec: &mut Vec<u8>, reader: &mut ReadHalf<'a>)
-> Result<usize, Box<dyn Error + Send + Sync>> {
if bytes_received <= 4 {
return Ok(0);
}
let total_packet_size = check_first_packet_segment(buffer_vec);
let mut total_packet_bytes_received = bytes_received - 4;
let packet_bytes_received_percent_step = (total_packet_size as f32 * 0.25f32) as usize;
let mut packet_bytes_received_step = packet_bytes_received_percent_step;
while total_packet_bytes_received < total_packet_size {
let mut buffer = [0u8; TCP_STREAM_READ_BUFFER_SIZE];
match timeout(Duration::from_secs(TCP_STREAM_READ_TIMEOUT_SECS), reader.read(&mut buffer)).await {
Ok(read_result) => {
match read_result {
Ok(bytes_received) => {
buffer_vec.extend(buffer[0..bytes_received].to_vec());
total_packet_bytes_received += bytes_received;
let progress_percentage = f32::round(total_packet_bytes_received as f32 /
total_packet_size as f32 * 100f32);
if total_packet_bytes_received > packet_bytes_received_step {
println!("Downloaded {}% of packet ({}b of {}b).", progress_percentage,
total_packet_bytes_received, total_packet_size);
packet_bytes_received_step += packet_bytes_received_percent_step;
}
},
Err(e) => return Err(Box::new(e))
}
},
Err(_) => return Err(Box::new(BantamError::ReadTimeout))
}
}
Ok(total_packet_size)
}
fn check_first_packet_segment(buffer: &mut Vec<u8>) -> usize {
let mut size_bytes = [0u8; 4];
for i in 0..4 {
size_bytes[i] = buffer.remove(0);
}
u32::from_le_bytes(size_bytes) as usize
}
async fn process_packet<T: ExternalSharedState + Send + Sync + 'static>(bytes: Vec<u8>, addr: SocketAddr,
tx: Tx, shared_state: AM<PeerSharedState>, ext_shared_state: AM<T>) -> Result<bool, Box<dyn Error + Send + Sync>> {
let (packet_type, mut stream) = deconstruct_bantam_packet(bytes);
match packet_type {
BantamPacketType::Handshake => {
process_handshake_packet(stream, addr, tx.clone(), shared_state.clone()).await?;
},
BantamPacketType::HandshakeResponse => {
process_handshake_response_packet(stream, addr, tx.clone(), shared_state.clone(),
ext_shared_state.clone()).await?;
},
BantamPacketType::Data => {
let data_packet = DataPacket::from_stream(&mut stream);
ext_shared_state.lock().await.on_receive_packet(data_packet.bytes, addr);
},
BantamPacketType::Bye => {
println!("Peer {} manually disconnected.", &addr);
return Ok(false);
},
}
Ok(true)
}
async fn process_handshake_packet(mut stream: BinaryStream, addr: SocketAddr, tx: Tx,
shared_state: AM<PeerSharedState>) -> Result<(), Box<dyn Error + Send + Sync>> {
let handshake = HandshakePacket::from_stream(&mut stream);
let mut listener_addr = addr.clone();
listener_addr.set_port(handshake.listening_port);
shared_state.lock().await.add_peer(addr, Peer {
listener_addr, sender: tx.clone()
});
let peer_addresses = match handshake.request_peers {
true => {
let mut peer_addresses = vec![];
for (_, peer) in shared_state.lock().await.peers.iter() {
if peer.listener_addr != listener_addr {
peer_addresses.push(SerializableSocketAddr::from_sock_addr(peer.listener_addr));
}
}
println!("Peer {} connected. Integrating into network...", &addr);
peer_addresses
},
false => {
println!("Peer {} connected.", &addr);
vec![]
}
};
send_bantam_packet_to(HandshakeResponsePacket::new(peer_addresses),
addr, shared_state.clone()).await
}
async fn process_handshake_response_packet<T: ExternalSharedState + Send + Sync + 'static>(
mut stream: BinaryStream, addr: SocketAddr, tx: Tx, shared_state: AM<PeerSharedState>,
ext_shared_state: AM<T>) -> Result<(), Box<dyn Error + Send + Sync>> {
shared_state.lock().await.add_peer(addr, Peer {
listener_addr: addr, sender: tx.clone()
});
let handshake_response = HandshakeResponsePacket::from_stream(&mut stream);
if handshake_response.peers.len() > 0 {
println!("Connecting with remaining peers in the network...");
for addr in handshake_response.peers {
let sock_addr = addr.to_sock_addr();
if !shared_state.lock().await.peers.contains_key(&sock_addr) {
if let Err(e) = setup_outgoing_peer(sock_addr, shared_state.clone(), false, ext_shared_state.clone()).await {
println!("Connection attempt with {} failed: {}.", sock_addr, e);
continue;
}
}
}
}
println!("Established connection with {}.", &addr);
ext_shared_state.lock().await.on_connected(addr);
Ok(())
}
async fn send_packet(bytes: Vec<u8>, shared_state: AM<PeerSharedState>)
-> Result<(), Box<dyn Error + Send + Sync>> {
shared_state.lock().await.broadcast(bytes).await
}
async fn send_packet_to(bytes: Vec<u8>, addr: SocketAddr, shared_state: AM<PeerSharedState>)
-> Result<(), Box<dyn Error + Send + Sync>> {
shared_state.lock().await.unicast(bytes, addr).await
}
fn construct_bantam_packet<T: PacketHeader<BantamPacketType> + Serializable>(
packet: T) -> Vec<u8> {
let mut stream = BinaryStream::new();
stream.write_packet_type(packet.get_type()).unwrap();
packet.to_stream(&mut stream);
let buffer = stream.get_buffer_vec();
let mut header = u32::to_le_bytes(buffer.len() as u32).to_vec();
header.extend(buffer);
header
}
fn deconstruct_bantam_packet(bytes: Vec<u8>) -> (BantamPacketType, BinaryStream) {
let mut stream = BinaryStream::from_bytes(&bytes);
(stream.read_packet_type::<BantamPacketType>().unwrap(), stream)
}
async fn send_bantam_packet<T: PacketHeader<BantamPacketType> + Serializable>(
packet: T, shared_state: AM<PeerSharedState>) -> Result<(), Box<dyn Error + Send + Sync>> {
send_packet(construct_bantam_packet(packet), shared_state).await
}
async fn send_bantam_packet_to<T: PacketHeader<BantamPacketType> + Serializable>(packet: T,
addr: SocketAddr, shared_state: AM<PeerSharedState>) -> Result<(), Box<dyn Error + Send + Sync>> {
send_packet_to(construct_bantam_packet(packet), addr, shared_state).await
}
pub async fn send_data_packet(bytes: Vec<u8>, shared_state: AM<PeerSharedState>)
-> Result<(), Box<dyn Error + Send + Sync>> {
send_packet(construct_bantam_packet(DataPacket::new(bytes)), shared_state).await
}
pub async fn send_data_packet_to(bytes: Vec<u8>, addr: SocketAddr, shared_state: AM<PeerSharedState>)
-> Result<(), Box<dyn Error + Send + Sync>> {
send_packet_to(construct_bantam_packet(DataPacket::new(bytes)), addr, shared_state).await
}