3 files changed, 199 insertions, 0 deletions
diff --git a/src/net/server/connection.rs b/src/net/server/connection.rs
new file mode 100644
index 0000000..801eb4b
--- /dev/null
+++ b/src/net/server/connection.rs
@@ -0,0 +1,84 @@
+//! A TCP-connection from a client to the server.
+
+use super::super::packet::{Packet, PacketRwError};
+use super::connection_manager::ConnId;
+use serde::de::DeserializeOwned;
+use serde::Serialize;
+use std::fmt::Debug;
+use std::net::TcpStream;
+use std::sync::mpsc::Sender;
+use std::thread::{self, JoinHandle};
+
+/// Holds a stream to the client and manages receiving packets from said client
+/// in an extra thread.
+pub struct Connection {
+    stream: TcpStream,
+    rcv_thread_handle: JoinHandle<()>,
+}
+
+impl Connection {
+    /// Start up the receiving thread after a client connection has been detected.
+    /// Will create a ghost disconnect packet in case the client disconnects.
+    pub(super) fn start_rcv<P>(
+        conn_id: ConnId,
+        stream: TcpStream,
+        packet_tx: Sender<(ConnId, Packet<P>)>,
+    ) -> Self
+    where
+        P: 'static + Debug + Send + DeserializeOwned + Serialize,
+    {
+        let mut stream_cl = stream
+            .try_clone()
+            .expect("Unable to clone TcpStream handle");
+        let rcv_thread_handle = thread::spawn(move || {
+            let mut running = true;
+            while running {
+                // Read the newest packet from the stream.
+                let packet = match Packet::read_from_stream(&mut stream_cl) {
+                    Ok(packet) => dbg!(packet),
+                    Err(PacketRwError::Closed) => {
+                        // Stop the thread after this packet.
+                        running = false;
+
+                        /* Generate an internal disconnection packet, so the connection
+                         * manager can call cleanup code if necessary.
+                         */
+                        Packet::Disconnect
+                    }
+                    Err(err) => {
+                        error!(
+                            "Receiving packet failed. Connection `{}`. {:?}",
+                            conn_id, err
+                        );
+
+                        // Ignore the received data.
+                        continue;
+                    }
+                };
+
+                /* Try sending the packet to the Connection manager. If it has already
+                 * stopped and hung up on the channel, stop this receive thread as well.
+                 */
+                if packet_tx.send((conn_id, packet)).is_err() {
+                    info!("Shutting down connection `{}`", conn_id);
+                    running = false;
+                }
+            }
+
+            info!("Packet receive thread has stopped running.");
+        });
+
+        Self {
+            stream,
+            rcv_thread_handle,
+        }
+    }
+
+    /// Send a packet to the client via TCP.
+    pub(super) fn send<P>(&mut self, packet: &Packet<P>) -> Result<(), PacketRwError>
+    where
+        P: 'static + Debug + Send + DeserializeOwned + Serialize,
+    {
+        packet.write_to_stream(&mut self.stream)
+    }
+}
diff --git a/src/net/server/connection_manager.rs b/src/net/server/connection_manager.rs
new file mode 100644
index 0000000..c47aa32
--- /dev/null
+++ b/src/net/server/connection_manager.rs
@@ -0,0 +1,109 @@
+//! The main server module, managing connections from clients.
+
+use super::super::packet::Packet;
+use super::connection::Connection;
+use crate::stable_vec::StableVec;
+use serde::de::DeserializeOwned;
+use serde::Serialize;
+use std::fmt::Debug;
+use std::io;
+use std::net::{SocketAddr, TcpListener};
+use std::sync::mpsc::{self, Receiver, Sender};
+use std::sync::{Arc, RwLock};
+use std::thread;
+
+/// Type of id for the connections inside of the connection manager.
+pub type ConnId = usize;
+
+/// Manages incoming connections to the servers and packets received from them.
+pub struct ConnectionManager<P: 'static + Send + Debug + DeserializeOwned> {
+    connections: Arc<RwLock<StableVec<Connection>>>,
+    local_port: u16,
+    _tx: Sender<(ConnId, Packet<P>)>,
+    rx: Receiver<(ConnId, Packet<P>)>,
+}
+
+impl<'de, P: 'static + Send + Debug + DeserializeOwned + Serialize> ConnectionManager<P> {
+    fn listen(
+        listener: TcpListener,
+        connections: Arc<RwLock<StableVec<Connection>>>,
+        packet_tx: Sender<(ConnId, Packet<P>)>,
+    ) {
+        for stream in listener.incoming() {
+            info!("Incoming connection.");
+            let stream = match stream {
+                Ok(stream) => stream,
+                Err(err) => {
+                    error!("Unable to accept client. {}", err);
+                    continue;
+                }
+            };
+
+            let mut connections = connections.write().unwrap();
+            let id = connections.next_free();
+            connections
+                .try_insert(id, Connection::start_rcv(id, stream, packet_tx.clone()))
+                .expect("Unable to insert client at supposedly valid id");
+            info!("Client `{}` connected.", id);
+        }
+
+        error!("Closing listener. This should never happen");
+    }
+
+    /// Start listening for connections. Returns the manager for connections,
+    /// which then can be asked about the connectins status and to send packets to
+    /// any client connected.
+    pub fn start(addr: SocketAddr) -> Result<Self, io::Error> {
+        let listener = TcpListener::bind(addr)?;
+        let local_port = listener.local_addr()?.port();
+        let connections = Arc::new(RwLock::new(StableVec::new()));
+
+        let (tx, rx) = mpsc::channel();
+        let tx_cl = tx.clone();
+        let connections_cl = connections.clone();
+        thread::spawn(move || Self::listen(listener, connections_cl, tx_cl));
+
+        Ok(Self {
+            connections,
+            local_port,
+            _tx: tx,
+            rx,
+        })
+    }
+
+    /// Try to receive the next packet. If no packet was received, this returns `None`. If the client
+    /// was disconnected, this also returns `None`.
+    pub fn next_packet(&self) -> Option<(ConnId, P)> {
+        match self.rx.try_recv() {
+            Ok((conn_id, Packet::Disconnect)) => {
+                self.connections.write().unwrap().remove(conn_id);
+                self.next_packet()
+            }
+            Ok((conn_id, Packet::Cargo(packet))) => Some((conn_id, packet)),
+            Err(_err) => None,
+        }
+    }
+
+    /// Send a packet to all clients currently connected
+    pub fn broadcast(&self, packet: P) -> bool {
+        let mut one_failed = false;
+        let mut conns = self.connections.write().unwrap();
+        let packet = Packet::Cargo(packet);
+        for (ref id, ref mut conn) in conns.id_iter_mut() {
+            if let Err(err) = conn.send(&packet) {
+                error!(
+                    "Broadcasting {:?} failed for client `{}`: {:?}",
+                    packet, id, err
+                );
+                one_failed = true;
+            }
+        }
+
+        !one_failed
+    }
+
+    /// Get the local port this connection manager's listener is bound to.
+    pub fn port(&self) -> u16 {
+        self.local_port
+    }
+}
diff --git a/src/net/server/mod.rs b/src/net/server/mod.rs
new file mode 100644
index 0000000..1f52ad5
--- /dev/null
+++ b/src/net/server/mod.rs
@@ -0,0 +1,6 @@
+//! Module containing network library server parts.
+
+pub mod connection;
+pub mod connection_manager;
+
+pub use connection_manager::*;