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use crate::{
buffer::NetworkBuffer,
error::{Error, Result},
packet::{deserialize_packet_header, serialize_packet, Packet, PacketBody, PACKET_HEADER_SIZE},
send_bytes, PacketRecipient,
};
use mio::{
net::{TcpListener, TcpStream},
Events, Interest, Poll, Token,
};
use std::{
collections::{HashMap, VecDeque},
io::Read,
net::SocketAddr,
};
const LOCAL_TOKEN: Token = Token(0);
const EVENTS_CAPACITY: usize = 4096;
pub enum ServerEvent {
ConnectionRejected(SocketAddr),
ClientConnected(Token, SocketAddr),
ClientDisconnected(Token),
ReceivedPacket(Token, usize),
SentPacket(Token, usize),
#[doc(hidden)]
__Nonexhaustive,
}
pub struct Connection {
token: Token,
socket: TcpStream,
is_disconnected: bool,
buffer: NetworkBuffer,
outgoing_packets: VecDeque<Box<dyn PacketBody>>,
}
impl Connection {
pub fn new(token: Token, socket: TcpStream) -> Self {
Connection {
token,
socket,
is_disconnected: false,
buffer: NetworkBuffer::new(),
outgoing_packets: VecDeque::new(),
}
}
}
pub struct Server {
tcp_listener: TcpListener,
events: Events,
poll: Poll,
connections: HashMap<Token, Connection>,
connection_limit: usize,
token_counter: usize,
incoming_packets: VecDeque<(Token, Packet)>,
}
impl Server {
/// Begin hosting a TCP server.
pub fn host(ip: &str, port: u16, connection_limit: usize) -> Result<Server> {
let address = format!("{}:{}", ip, port).parse().unwrap();
let mut tcp_listener = TcpListener::bind(address)?;
// Register to read events
let poll = Poll::new().unwrap();
poll.registry()
.register(&mut tcp_listener, LOCAL_TOKEN, Interest::READABLE)?;
Ok(Server {
tcp_listener,
events: Events::with_capacity(EVENTS_CAPACITY),
poll,
connections: HashMap::new(),
connection_limit,
token_counter: 0,
incoming_packets: VecDeque::new(),
})
}
/// Get the current number of connections.
pub fn num_connections(&self) -> usize {
self.connections.len()
}
/// Get the maximum number of connections allowed.
pub fn connection_limit(&self) -> usize {
self.connection_limit
}
/// Drain any incoming packets and return them.
pub fn drain_incoming_packets(&mut self) -> Vec<(Token, Packet)> {
self.incoming_packets.drain(..).collect()
}
/// Kick a connection from the server.
pub fn kick(&mut self, connection_token: Token) -> Result<()> {
let conn: &mut Connection = match self.connections.get_mut(&connection_token) {
Some(c) => c,
None => {
return Err(Error::ConnectionNotFound);
}
};
conn.is_disconnected = true;
Ok(())
}
/// Send a packet.
/// This function will box the packet, then queue it to be sent on the next server tick.
pub fn send(&mut self, recipient: PacketRecipient, packet: impl PacketBody) {
let boxed: Box<dyn PacketBody> = Box::new(packet);
self.send_boxed(recipient, boxed);
}
/// Send a boxed packet.
/// Similar to `send`, but this is moreuseful when you have a boxed packet already and don't want
/// to cast it to a concrete type before sending it.
pub fn send_boxed(&mut self, recipient: PacketRecipient, packet_boxed: Box<dyn PacketBody>) {
match recipient {
PacketRecipient::All => {
for (_, connection) in self.connections.iter_mut() {
connection.outgoing_packets.push_back(packet_boxed.clone());
}
}
PacketRecipient::Single(t) => {
if let Some(connection) = self.connections.get_mut(&t) {
connection.outgoing_packets.push_back(packet_boxed);
}
}
PacketRecipient::Exclude(t) => {
let filtered = self.connections.iter_mut().filter(|(tok, _c)| tok.0 != t.0);
for (_token, connection) in filtered {
connection.outgoing_packets.push_back(packet_boxed.clone());
}
}
PacketRecipient::ExcludeMany(filter) => {
let filtered = self
.connections
.iter_mut()
.filter(|(tok, _c)| !filter.contains(tok));
for (_token, connection) in filtered {
connection.outgoing_packets.push_back(packet_boxed.clone());
}
}
PacketRecipient::Include(targets) => {
let filtered = self
.connections
.iter_mut()
.filter(|(tok, _c)| targets.contains(tok));
for (_token, connection) in filtered {
connection.outgoing_packets.push_back(packet_boxed.clone());
}
}
}
}
/// Runs a network tick, which sends/receives packets based on socket readiness, as well as accepts new connections.
pub fn tick(&mut self) -> Vec<ServerEvent> {
let timeout_dur = std::time::Duration::from_millis(1);
self.poll
.poll(&mut self.events, Some(timeout_dur))
.unwrap_or_else(|e| panic!("Failed to poll for new events! {}", e));
let mut net_events: Vec<ServerEvent> = Vec::new();
for event in self.events.iter() {
match event.token() {
// Local socket is ready to accept
LOCAL_TOKEN => loop {
let (mut socket, addr) = match self.tcp_listener.accept() {
Ok((socket, addr)) => (socket, addr),
Err(e) => {
if e.kind() == std::io::ErrorKind::WouldBlock {
break;
}
println!("{}", e);
break;
}
};
if self.num_connections() >= self.connection_limit() {
println!("Rejecting connection from {}, server is full!", addr.ip());
net_events.push(ServerEvent::ConnectionRejected(addr));
continue;
}
// Increment our token counter, then create a new token for this connection
self.token_counter += 1;
let token = Token(self.token_counter);
// Register the new socket to receive events
self.poll.registry().register(
&mut socket,
token,
Interest::READABLE | Interest::WRITABLE,
).unwrap_or_else(|e| panic!("Failed to register poll for new connection (Token {}, Address {}). {}", token.0, addr, e));
// Insert the new connection
self.connections
.insert(token, Connection::new(token, socket));
net_events.push(ServerEvent::ClientConnected(token, addr));
},
// Connection socket is ready to read/write
token => {
// Get the connection
let conn: &mut Connection =
self.connections.get_mut(&token).unwrap_or_else(|| {
panic!(
"Attempted to handle socket event for non-existent connection {}!",
token.0
)
});
// Handle reading
if event.is_readable() {
// Loop and read bytes into this connections buffer, until there are no more incoming bytes
let buffer = &mut conn.buffer.data[conn.buffer.offset..];
loop {
match conn.socket.read(buffer) {
Ok(0) => {
// "Read" 0 bytes, which means the socket has closed
conn.is_disconnected = true;
break;
}
Ok(read_bytes) => {
// Read some bytes
conn.buffer.offset += read_bytes;
}
Err(e) => {
// Socket is not ready anymore, stop reading
if e.kind() == std::io::ErrorKind::WouldBlock {
break;
} else {
eprintln!("Unexpected error when reading bytes from connection {}! {}", conn.token.0, e);
conn.is_disconnected = true;
break;
}
}
}
}
// Process incoming bytes into packets
while let Ok(header) = deserialize_packet_header(&mut conn.buffer) {
// Now make sure we have enough bytes for at the rest of this packet
let packet_size = PACKET_HEADER_SIZE + (header.size as usize);
if conn.buffer.offset < packet_size {
break;
}
// Drain the packet bytes from the front of the buffer
let bytes: &[u8] = &conn.buffer.data[PACKET_HEADER_SIZE..packet_size];
let body = bytes.to_vec();
conn.buffer.drain(packet_size);
let packet = Packet { header, body };
self.incoming_packets.push_back((token, packet));
net_events.push(ServerEvent::ReceivedPacket(conn.token, packet_size));
}
}
// Handle writing
if event.is_writable() {
while let Some(packet) = conn.outgoing_packets.pop_front() {
let data = match serialize_packet(packet) {
Ok(d) => d,
Err(e) => {
eprintln!("Failed to serialize packet! {}", e);
continue;
}
};
match send_bytes(&mut conn.socket, &data) {
Ok(sent_bytes) => {
net_events.push(ServerEvent::SentPacket(token, sent_bytes));
}
Err(e) => {
eprintln!(
"Unexpected error when sending bytes to connection {}! {}",
conn.token.0, e
);
conn.is_disconnected = true;
break;
}
}
}
}
// We're done processing events for this connection for this tick.
// Reregister for next tick.
self.poll
.registry()
.reregister(
&mut conn.socket,
conn.token,
Interest::READABLE | Interest::WRITABLE,
)
.unwrap_or_else(|e| {
panic!(
"Failed to reregister poll for connection (Token {}). {}",
token.0, e
)
});
}
}
}
// Iterate through disconnected connections and send ClientDisconnected event
for (tok, _) in self.connections.iter().filter(|&(_, c)| c.is_disconnected) {
net_events.push(ServerEvent::ClientDisconnected(*tok));
}
// Retain any connections which aren't disconnected
self.connections.retain(|_, v| !v.is_disconnected);
net_events
}
}