diff --git a/cove-core/src/packets.rs b/cove-core/src/packets.rs
index 7b27f08..0e179fc 100644
--- a/cove-core/src/packets.rs
+++ b/cove-core/src/packets.rs
@@ -51,7 +51,6 @@ pub struct SendCmd {
 #[serde(tag = "type")]
 pub enum SendRpl {
     Success { message: Message },
-    InvalidNick { reason: String },
     InvalidContent { reason: String },
 }
 
diff --git a/cove-server/src/main.rs b/cove-server/src/main.rs
index 89c8656..1be03c9 100644
--- a/cove-server/src/main.rs
+++ b/cove-server/src/main.rs
@@ -1,27 +1,28 @@
 mod conn;
+mod util;
 
+use std::any;
 use std::collections::HashMap;
-use std::hash::Hash;
 use std::sync::Arc;
-use std::time::{SystemTime, UNIX_EPOCH};
+use std::time::{Duration, SystemTime, UNIX_EPOCH};
 
 use anyhow::anyhow;
-use cove_core::packets::{Cmd, HelloRpl, Packet, Rpl};
-use cove_core::{Identity, MessageId, Session, SessionId};
-use futures::stream::{SplitSink, SplitStream};
-use futures::{future, Sink, SinkExt, Stream, StreamExt, TryStreamExt};
-use rand::prelude::ThreadRng;
+use conn::{ConnMaintenance, ConnRx, ConnTx};
+use cove_core::packets::{
+    Cmd, HelloCmd, HelloRpl, JoinNtf, NickCmd, NickNtf, NickRpl, Ntf, Packet, PartNtf, SendCmd,
+    SendNtf, SendRpl, WhoCmd,
+};
+use cove_core::{Identity, Message, MessageId, Session, SessionId};
 use rand::Rng;
 use tokio::net::{TcpListener, TcpStream};
-use tokio::sync::mpsc::{self, UnboundedSender};
-use tokio::sync::{self, Mutex, RwLock};
-use tokio_tungstenite::tungstenite::Message as TkMessage;
-use tokio_tungstenite::WebSocketStream;
+use tokio::sync::Mutex;
+use tokio_tungstenite::tungstenite::http::header::LAST_MODIFIED;
+use util::timestamp;
 
-#[derive(Debug)]
+#[derive(Debug, Clone)]
 struct Client {
     session: Session,
-    packets: UnboundedSender<Packet>,
+    send: ConnTx,
 }
 
 #[derive(Debug)]
@@ -36,12 +37,157 @@ impl Room {
         Self {
             clients: HashMap::new(),
             last_message: MessageId::of(&format!("{}", rand::thread_rng().gen::<u64>())),
-            last_timestamp: SystemTime::now()
-                .duration_since(UNIX_EPOCH)
-                .expect("executed after 1970")
-                .as_millis(),
+            last_timestamp: util::timestamp(),
         }
     }
+
+    fn client(&self, id: SessionId) -> &Client {
+        self.clients.get(&id).expect("invalid session id")
+    }
+
+    fn client_mut(&mut self, id: SessionId) -> &mut Client {
+        self.clients.get_mut(&id).expect("invalid session id")
+    }
+
+    fn notify_all(&self, packet: &Packet) {
+        for client in self.clients.values() {
+            let _ = client.send.send(packet);
+        }
+    }
+
+    fn notify_except(&self, id: SessionId, packet: &Packet) {
+        for client in self.clients.values() {
+            if client.session.id != id {
+                let _ = client.send.send(packet);
+            }
+        }
+    }
+
+    fn part(&mut self, id: SessionId) {
+        let client = self.clients.remove(&id).expect("invalid session id");
+
+        self.notify_all(&Packet::ntf(PartNtf {
+            who: client.session,
+        }));
+    }
+
+    fn join(&mut self, client: Client) {
+        self.notify_all(&Packet::ntf(JoinNtf {
+            who: client.session.clone(),
+        }));
+
+        self.clients.insert(client.session.id, client);
+    }
+
+    fn nick(&mut self, id: SessionId, nick: String) {
+        let who = {
+            let client = self.client_mut(id);
+            client.session.nick = nick;
+            client.session.clone()
+        };
+
+        self.notify_except(id, &Packet::ntf(NickNtf { who }))
+    }
+
+    fn send(&mut self, id: SessionId, parent: Option<MessageId>, content: String) -> Message {
+        let client = &self.clients[&id];
+
+        self.last_timestamp = util::timestamp_after(self.last_timestamp);
+
+        let message = Message {
+            time: self.last_timestamp,
+            pred: self.last_message,
+            parent,
+            identity: client.session.identity,
+            nick: client.session.nick.clone(),
+            content,
+        };
+
+        self.notify_except(
+            id,
+            &Packet::ntf(SendNtf {
+                message: message.clone(),
+            }),
+        );
+
+        message
+    }
+}
+
+#[derive(Debug)]
+struct ServerSession {
+    tx: ConnTx,
+    rx: ConnRx,
+    room: Arc<Mutex<Room>>,
+    session: Session,
+}
+
+impl ServerSession {
+    fn new(tx: ConnTx, rx: ConnRx, room: Arc<Mutex<Room>>, session: Session) -> Self {
+        Self {
+            tx,
+            rx,
+            room,
+            session,
+        }
+    }
+
+    async fn handle_nick(&mut self, id: u64, cmd: NickCmd) -> anyhow::Result<()> {
+        if let Some(reason) = util::check_nick(&cmd.nick) {
+            self.tx
+                .send(&Packet::rpl(id, NickRpl::InvalidNick { reason }))?;
+            return Ok(());
+        }
+
+        self.session.nick = cmd.nick.clone();
+        self.tx.send(&Packet::rpl(id, NickRpl::Success))?;
+        self.room.lock().await.nick(self.session.id, cmd.nick);
+
+        Ok(())
+    }
+
+    async fn handle_send(&mut self, id: u64, cmd: SendCmd) -> anyhow::Result<()> {
+        if let Some(reason) = util::check_content(&cmd.content) {
+            self.tx
+                .send(&Packet::rpl(id, SendRpl::InvalidContent { reason }))?;
+            return Ok(());
+        }
+
+        let message = self
+            .room
+            .lock()
+            .await
+            .send(self.session.id, cmd.parent, cmd.content);
+
+        self.tx
+            .send(&Packet::rpl(id, SendRpl::Success { message }))?;
+
+        Ok(())
+    }
+
+    async fn handle_who(&mut self, id: u64, cmd: WhoCmd) -> anyhow::Result<()> {
+        todo!()
+    }
+
+    async fn handle_packet(&mut self, packet: Packet) -> anyhow::Result<()> {
+        match packet {
+            Packet::Cmd { id, cmd } => match cmd {
+                Cmd::Hello(_) => Err(anyhow!("unexpected Hello cmd")),
+                Cmd::Nick(cmd) => self.handle_nick(id, cmd).await,
+                Cmd::Send(cmd) => self.handle_send(id, cmd).await,
+                Cmd::Who(cmd) => self.handle_who(id, cmd).await,
+            },
+            Packet::Rpl { .. } => Err(anyhow!("unexpected rpl")),
+            Packet::Ntf { .. } => Err(anyhow!("unexpected ntf")),
+        }
+    }
+
+    async fn run(&mut self) -> anyhow::Result<()> {
+        while let Some(packet) = self.rx.recv().await? {
+            self.handle_packet(packet).await?;
+        }
+        Ok(())
+    }
 }
 
 #[derive(Debug, Clone)]
@@ -65,129 +211,105 @@ impl Server {
             .clone()
     }
 
-    async fn recv(rx: &mut SplitStream<WebSocketStream<TcpStream>>) -> anyhow::Result<Packet> {
-        loop {
-            let msg = rx.next().await.ok_or(anyhow!("connection closed"))??;
-            let str = match msg {
-                TkMessage::Text(str) => str,
-                TkMessage::Ping(_) | TkMessage::Pong(_) => continue,
-                TkMessage::Binary(_) => return Err(anyhow!("invalid binary packet")),
-                TkMessage::Close(_) => return Err(anyhow!("connection closed")),
-            };
-            break Ok(serde_json::from_str(&str)?);
-        }
-    }
-
-    async fn send(
-        tx: &mut SplitSink<WebSocketStream<TcpStream>, TkMessage>,
-        packet: &Packet,
-    ) -> anyhow::Result<()> {
-        let str = serde_json::to_string(packet).expect("serialisable packet");
-        let msg = TkMessage::Text(str);
-        tx.feed(msg).await?;
-        tx.flush().await?;
-        Ok(())
-    }
-
-    fn check_room(room: &str) -> Option<String> {
-        if !room.is_empty() {
-            return Some("is empty".to_string());
-        }
-        if !room.is_ascii() {
-            return Some("contains non-ascii characters".to_string());
-        }
-        if room.len() > 1024 {
-            return Some("contains more than 1024 characters".to_string());
-        }
-        if !room
-            .chars()
-            .all(|c| c == '-' || c == '.' || ('a'..='z').contains(&c))
-        {
-            return Some("must only contain a-z, '-' and '_'".to_string());
-        }
-        None
-    }
-
-    fn check_nick(nick: &str) -> Option<String> {
-        if !nick.is_empty() {
-            return Some("is empty".to_string());
-        }
-        if !nick.trim().is_empty() {
-            return Some("contains only whitespace".to_string());
-        }
-        let nick = nick.trim();
-        if nick.chars().count() > 1024 {
-            return Some("contains more than 1024 characters".to_string());
-        }
-        None
-    }
-
-    fn check_identity(identity: &str) -> Option<String> {
-        if identity.chars().count() > 32768 {
-            return Some("contains more than 32768 characters".to_string());
-        }
-        None
-    }
-
-    async fn greet(
+    async fn handle_hello(
         &self,
-        tx: &mut SplitSink<WebSocketStream<TcpStream>, TkMessage>,
-        rx: &mut SplitStream<WebSocketStream<TcpStream>>,
-    ) -> anyhow::Result<(String, Session, u64)> {
-        // TODO Allow multiple Hello commands until the first succeeds
-        let packet = Self::recv(rx).await?;
-        let (id, cmd) = match packet {
-            Packet::Cmd {
-                id,
-                cmd: Cmd::Hello(cmd),
-            } => (id, cmd),
-            _ => return Err(anyhow!("not a hello command")),
-        };
-        if let Some(reason) = Self::check_room(&cmd.room) {
-            Self::send(tx, &Packet::rpl(id, HelloRpl::InvalidRoom { reason })).await?;
-            return Err(anyhow!("invalid room"));
+        tx: &ConnTx,
+        id: u64,
+        cmd: HelloCmd,
+    ) -> anyhow::Result<Option<(String, Session)>> {
+        if let Some(reason) = util::check_room(&cmd.room) {
+            tx.send(&Packet::rpl(id, HelloRpl::InvalidRoom { reason }))?;
+            return Ok(None);
         }
-        if let Some(reason) = Self::check_nick(&cmd.nick) {
-            Self::send(tx, &Packet::rpl(id, HelloRpl::InvalidNick { reason })).await?;
-            return Err(anyhow!("invalid nick"));
+        if let Some(reason) = util::check_nick(&cmd.nick) {
+            tx.send(&Packet::rpl(id, HelloRpl::InvalidNick { reason }))?;
+            return Ok(None);
         }
-        if let Some(reason) = Self::check_identity(&cmd.identity) {
-            Self::send(tx, &Packet::rpl(id, HelloRpl::InvalidNick { reason })).await?;
-            return Err(anyhow!("invalid identity"));
+        if let Some(reason) = util::check_identity(&cmd.identity) {
+            tx.send(&Packet::rpl(id, HelloRpl::InvalidIdentity { reason }))?;
+            return Ok(None);
         }
+
         let session = Session {
             id: SessionId::of(&format!("{}", rand::thread_rng().gen::<u64>())),
             nick: cmd.nick,
             identity: Identity::of(&cmd.identity),
         };
-        Ok((cmd.room, session, id))
+
+        Ok(Some((cmd.room, session)))
     }
 
-    async fn on_conn(self, stream: TcpStream) {
+    async fn greet(&self, tx: ConnTx, mut rx: ConnRx) -> anyhow::Result<ServerSession> {
+        let (id, room, session) = loop {
+            let (id, cmd) = match rx.recv().await? {
+                Some(Packet::Cmd {
+                    id,
+                    cmd: Cmd::Hello(cmd),
+                }) => (id, cmd),
+                _ => return Err(anyhow!("not a Hello command")),
+            };
+
+            if let Some((room, session)) = self.handle_hello(&tx, id, cmd).await? {
+                break (id, room, session);
+            }
+        };
+
+        let room = self.room(room).await;
+
+        {
+            let mut room = room.lock().await;
+
+            let you = session.clone();
+            let others = room
+                .clients
+                .values()
+                .map(|client| client.session.clone())
+                .collect::<Vec<_>>();
+            let last_message = room.last_message;
+
+            tx.send(&Packet::rpl(
+                id,
+                HelloRpl::Success {
+                    you,
+                    others,
+                    last_message,
+                },
+            ))?;
+
+            room.join(Client {
+                session: session.clone(),
+                send: tx.clone(),
+            });
+        }
+
+        Ok(ServerSession {
+            tx,
+            rx,
+            room,
+            session,
+        })
+    }
+    async fn greet_and_run(&self, tx: ConnTx, rx: ConnRx) -> anyhow::Result<()> {
+        let mut session = self.greet(tx, rx).await?;
+        let result = session.run().await;
+        session.room.lock().await.part(session.session.id);
+        result
+    }
+
+    /// Wrapper for [`ConnMaintenance::perform`] so it returns an
+    /// [`anyhow::Result`].
+    async fn maintain(maintenance: ConnMaintenance) -> anyhow::Result<()> {
+        maintenance.perform().await?;
+        Ok(())
+    }
+
+    async fn on_conn(self, stream: TcpStream) -> anyhow::Result<()> {
         // TODO Ping-pong starting from the beginning (not just after hello)
         println!("Connection from {}", stream.peer_addr().unwrap());
         let stream = tokio_tungstenite::accept_async(stream).await.unwrap();
-        let (mut tx, mut rx) = stream.split();
-        let (room, session, id) = match self.greet(&mut tx, &mut rx).await {
-            Ok(info) => info,
-            Err(_) => return,
-        };
-        let room = self.room(room).await;
-        let (packets, client_rx) = mpsc::unbounded_channel();
-        {
-            let mut room = room.lock().await;
-            packets.send(Packet::rpl(
-                id,
-                HelloRpl::Success {
-                    you: session.clone(),
-                    others: room.clients.values().map(|c| c.session.clone()).collect(),
-                    last_message: room.last_message,
-                },
-            ));
-            let client = Client { session, packets };
-            room.clients.insert(client.session.id, client);
-        }
-        todo!()
+        let (tx, rx, maintenance) = conn::new(stream, Duration::from_secs(10))?;
+        tokio::try_join!(self.greet_and_run(tx, rx), Self::maintain(maintenance))?;
+        Ok(())
     }
 }
 
diff --git a/cove-server/src/util.rs b/cove-server/src/util.rs
new file mode 100644
index 0000000..3d48c41
--- /dev/null
+++ b/cove-server/src/util.rs
@@ -0,0 +1,60 @@
+use std::cmp;
+use std::time::{SystemTime, UNIX_EPOCH};
+
+pub fn timestamp() -> u128 {
+    SystemTime::now()
+        .duration_since(UNIX_EPOCH)
+        .expect("executed after 1970")
+        .as_millis()
+}
+
+pub fn timestamp_after(previous: u128) -> u128 {
+    cmp::max(timestamp(), previous + 1)
+}
+
+pub fn check_room(room: &str) -> Option<String> {
+    if !room.is_empty() {
+        return Some("is empty".to_string());
+    }
+    if !room.is_ascii() {
+        return Some("contains non-ascii characters".to_string());
+    }
+    if room.len() > 1024 {
+        return Some("contains more than 1024 characters".to_string());
+    }
+    if !room
+        .chars()
+        .all(|c| c == '-' || c == '.' || ('a'..='z').contains(&c))
+    {
+        return Some("must only contain a-z, '-' and '_'".to_string());
+    }
+    None
+}
+
+pub fn check_nick(nick: &str) -> Option<String> {
+    if !nick.is_empty() {
+        return Some("is empty".to_string());
+    }
+    if !nick.trim().is_empty() {
+        return Some("contains only whitespace".to_string());
+    }
+    let nick = nick.trim();
+    if nick.chars().count() > 1024 {
+        return Some("contains more than 1024 characters".to_string());
+    }
+    None
+}
+
+pub fn check_identity(identity: &str) -> Option<String> {
+    if identity.chars().count() > 32 * 1024 {
+        return Some("contains more than 32768 characters".to_string());
+    }
+    None
+}
+
+pub fn check_content(content: &str) -> Option<String> {
+    if content.chars().count() > 128 * 1024 {
+        return Some("contains more than 131072 characters".to_string());
+    }
+    None
+}