feat: multi-party rooms (SFU) + push-to-talk radio mode

Room-based SFU relay:
- Clients join named rooms (room name from QUIC SNI)
- Each participant's packets forwarded to all others (no mixing)
- Multiple rooms run concurrently on one relay
- Web bridge passes room name from URL path to relay

Push-to-talk (radio mode):
- Toggle "Radio mode" checkbox after connecting
- Hold PTT button or spacebar to transmit
- Release to mute mic (receive-only)
- Works on desktop (spacebar) and mobile (touch)

URL routing:
- /myroom → joins room "myroom"
- Room name input field as fallback

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

crates/wzp-relay/Cargo.toml

@@ -21,6 +21,7 @@ serde = { workspace = true }
 toml = "0.8"
 anyhow = "1"
 rustls = { version = "0.23", default-features = false, features = ["ring", "std"] }
+quinn = { workspace = true }
 
 [[bin]]
 name = "wzp-relay"

crates/wzp-relay/src/lib.rs

@@ -10,6 +10,7 @@
 pub mod config;
 pub mod handshake;
 pub mod pipeline;
+pub mod room;
 pub mod session_mgr;
 
 pub use config::RelayConfig;

crates/wzp-relay/src/main.rs

@@ -1,7 +1,11 @@
 //! WarzonePhone relay daemon entry point.
 //!
-//! Accepts client QUIC connections and bridges pairs of clients together.
-//! When a --remote relay is configured, forwards traffic to it instead.
+//! Supports two modes:
+//! - **Room mode** (default): clients join named rooms, packets forwarded to all others (SFU)
+//! - **Forward mode** (--remote): all traffic forwarded to a remote relay
+//!
+//! Room names are passed via the QUIC SNI (server_name) field.
+//! The web bridge connects with room name as SNI.
 
 use std::net::SocketAddr;
 use std::sync::atomic::{AtomicU64, Ordering};
@@ -14,7 +18,7 @@ use tracing::{error, info};
 use wzp_proto::MediaTransport;
 use wzp_relay::config::RelayConfig;
 use wzp_relay::pipeline::{PipelineConfig, RelayPipeline};
-use wzp_relay::session_mgr::SessionManager;
+use wzp_relay::room::{self, RoomManager};
 
 fn parse_args() -> RelayConfig {
     let mut config = RelayConfig::default();
@@ -39,7 +43,12 @@ fn parse_args() -> RelayConfig {
                 eprintln!();
                 eprintln!("Options:");
                 eprintln!("  --listen <addr>  Listen address (default: 0.0.0.0:4433)");
-                eprintln!("  --remote <addr>  Remote relay address for forwarding");
+                eprintln!("  --remote <addr>  Remote relay for forwarding (disables room mode)");
+                eprintln!();
+                eprintln!("Room mode (default):");
+                eprintln!("  Clients join rooms by name. Packets are forwarded to all");
+                eprintln!("  other participants in the same room (SFU model).");
+                eprintln!("  Room name comes from QUIC SNI or defaults to 'default'.");
                 std::process::exit(0);
             }
             other => {
@@ -57,78 +66,6 @@ struct RelayStats {
     downstream_packets: AtomicU64,
 }
 
-/// Bridge two transports: A's packets go to B, B's go to A.
-async fn run_bridge(
-    a: Arc<wzp_transport::QuinnTransport>,
-    b: Arc<wzp_transport::QuinnTransport>,
-    a_addr: SocketAddr,
-    b_addr: SocketAddr,
-) {
-    info!(%a_addr, %b_addr, "bridging two clients");
-
-    let stats = Arc::new(RelayStats {
-        upstream_packets: AtomicU64::new(0),
-        downstream_packets: AtomicU64::new(0),
-    });
-
-    let stats_log = stats.clone();
-    let stats_handle = tokio::spawn(async move {
-        let mut interval = tokio::time::interval(Duration::from_secs(5));
-        loop {
-            interval.tick().await;
-            let ab = stats_log.upstream_packets.load(Ordering::Relaxed);
-            let ba = stats_log.downstream_packets.load(Ordering::Relaxed);
-            info!(a_to_b = ab, b_to_a = ba, "bridge stats");
-        }
-    });
-
-    let a1 = a.clone();
-    let b1 = b.clone();
-    let s1 = stats.clone();
-    let a_to_b = tokio::spawn(async move {
-        loop {
-            match a1.recv_media().await {
-                Ok(Some(pkt)) => {
-                    if let Err(e) = b1.send_media(&pkt).await {
-                        error!("A→B send error: {e}");
-                        break;
-                    }
-                    s1.upstream_packets.fetch_add(1, Ordering::Relaxed);
-                }
-                Ok(None) => { info!(%a_addr, "client A disconnected"); break; }
-                Err(e) => { error!(%a_addr, "A recv error: {e}"); break; }
-            }
-        }
-    });
-
-    let a2 = a.clone();
-    let b2 = b.clone();
-    let s2 = stats.clone();
-    let b_to_a = tokio::spawn(async move {
-        loop {
-            match b2.recv_media().await {
-                Ok(Some(pkt)) => {
-                    if let Err(e) = a2.send_media(&pkt).await {
-                        error!("B→A send error: {e}");
-                        break;
-                    }
-                    s2.downstream_packets.fetch_add(1, Ordering::Relaxed);
-                }
-                Ok(None) => { info!(%b_addr, "client B disconnected"); break; }
-                Err(e) => { error!(%b_addr, "B recv error: {e}"); break; }
-            }
-        }
-    });
-
-    tokio::select! {
-        _ = a_to_b => {}
-        _ = b_to_a => {}
-    }
-    stats_handle.abort();
-    info!(%a_addr, %b_addr, "bridge ended");
-}
-
-/// Run upstream forwarding: client → pipeline → remote.
 async fn run_upstream(
     client: Arc<wzp_transport::QuinnTransport>,
     remote: Arc<wzp_transport::QuinnTransport>,
@@ -159,7 +96,6 @@ async fn run_upstream(
     }
 }
 
-/// Run downstream forwarding: remote → pipeline → client.
 async fn run_downstream(
     client: Arc<wzp_transport::QuinnTransport>,
     remote: Arc<wzp_transport::QuinnTransport>,
@@ -190,12 +126,6 @@ async fn run_downstream(
     }
 }
 
-/// Waiting client: address + transport.
-struct WaitingClient {
-    addr: SocketAddr,
-    transport: Arc<wzp_transport::QuinnTransport>,
-}
-
 #[tokio::main]
 async fn main() -> anyhow::Result<()> {
     let config = parse_args();
@@ -205,29 +135,24 @@ async fn main() -> anyhow::Result<()> {
         .expect("failed to install rustls crypto provider");
 
     info!(addr = %config.listen_addr, "WarzonePhone relay starting");
-    if let Some(remote) = config.remote_relay {
-        info!(%remote, "forwarding mode → remote relay");
-    } else {
-        info!("bridge mode — pairs clients together (echo when alone)");
-    }
 
     let (server_config, _cert) = wzp_transport::server_config();
     let endpoint = wzp_transport::create_endpoint(config.listen_addr, Some(server_config))?;
 
-    let _sessions = Arc::new(Mutex::new(SessionManager::new(config.max_sessions)));
-
-    // Remote relay transport (forwarding mode only)
+    // Forward mode
     let remote_transport: Option<Arc<wzp_transport::QuinnTransport>> =
         if let Some(remote_addr) = config.remote_relay {
+            info!(%remote_addr, "forward mode → remote relay");
             let client_cfg = wzp_transport::client_config();
             let conn = wzp_transport::connect(&endpoint, remote_addr, "localhost", client_cfg).await?;
             Some(Arc::new(wzp_transport::QuinnTransport::new(conn)))
         } else {
+            info!("room mode — clients join named rooms (SFU)");
             None
         };
 
-    // Bridge mode: slot for waiting client
-    let waiting: Arc<Mutex<Option<WaitingClient>>> = Arc::new(Mutex::new(None));
+    // Room manager (room mode only)
+    let room_mgr = Arc::new(Mutex::new(RoomManager::new()));
 
     info!("Listening for connections...");
 
@@ -238,15 +163,27 @@ async fn main() -> anyhow::Result<()> {
         };
 
         let remote_transport = remote_transport.clone();
-        let waiting = waiting.clone();
+        let room_mgr = room_mgr.clone();
 
         tokio::spawn(async move {
             let addr = connection.remote_address();
+
+            // Extract room name from QUIC handshake data (SNI).
+            // The web bridge connects with the room name as server_name.
+            let room_name = connection
+                .handshake_data()
+                .and_then(|hd| {
+                    hd.downcast::<quinn::crypto::rustls::HandshakeData>().ok()
+                })
+                .and_then(|hd| hd.server_name.clone())
+                .unwrap_or_else(|| "default".to_string());
+
             let transport = Arc::new(wzp_transport::QuinnTransport::new(connection));
-            info!(%addr, "new client");
+
+            info!(%addr, room = %room_name, "new client");
 
             if let Some(remote) = remote_transport {
-                // Forwarding mode
+                // Forward mode — same as before
                 let stats = Arc::new(RelayStats {
                     upstream_packets: AtomicU64::new(0),
                     downstream_packets: AtomicU64::new(0),
@@ -273,71 +210,21 @@ async fn main() -> anyhow::Result<()> {
                 tokio::select! { _ = up => {} _ = dn => {} }
                 stats_handle.abort();
                 transport.close().await.ok();
-                info!(%addr, "forwarding session ended");
             } else {
-                // Bridge mode — try to pair with a waiting client
-                let peer = {
-                    let mut slot = waiting.lock().await;
-                    slot.take()
+                // Room mode — join room and forward to all others
+                let participant_id = {
+                    let mut mgr = room_mgr.lock().await;
+                    mgr.join(&room_name, addr, transport.clone())
                 };
 
-                if let Some(peer_client) = peer {
-                    // Second client — bridge immediately
-                    run_bridge(peer_client.transport.clone(), transport.clone(), peer_client.addr, addr).await;
-                    peer_client.transport.close().await.ok();
-                    transport.close().await.ok();
+                room::run_participant(
+                    room_mgr.clone(),
+                    room_name,
+                    participant_id,
+                    transport.clone(),
+                ).await;
 
-                    // After bridge ends, clean up so next pair can form
-                    info!("bridge complete, ready for next pair");
-                } else {
-                    // First client — register and wait
-                    {
-                        let mut slot = waiting.lock().await;
-                        *slot = Some(WaitingClient { addr, transport: transport.clone() });
-                    }
-                    info!(%addr, "waiting for peer (echo in meantime)");
-
-                    // Echo loop — but check periodically if we've been claimed by a bridge
-                    loop {
-                        // Check if we've been taken from the waiting slot
-                        // (meaning a second client connected and started the bridge)
-                        {
-                            let slot = waiting.lock().await;
-                            if slot.is_none() {
-                                // We were taken — a bridge is running with our transport.
-                                // Just exit this task; the bridge task handles everything.
-                                info!(%addr, "peer connected, exiting echo loop");
-                                return;
-                            }
-                        }
-
-                        // Echo with a short timeout so we can check the slot again
-                        match tokio::time::timeout(
-                            Duration::from_millis(100),
-                            transport.recv_media()
-                        ).await {
-                            Ok(Ok(Some(pkt))) => {
-                                let _ = transport.send_media(&pkt).await;
-                            }
-                            Ok(Ok(None)) => {
-                                info!(%addr, "disconnected while waiting");
-                                // Clean up our slot
-                                let mut slot = waiting.lock().await;
-                                *slot = None;
-                                return;
-                            }
-                            Ok(Err(e)) => {
-                                error!(%addr, "echo error: {e}");
-                                let mut slot = waiting.lock().await;
-                                *slot = None;
-                                return;
-                            }
-                            Err(_) => {
-                                // Timeout — loop back and check if we got paired
-                            }
-                        }
-                    }
-                }
+                transport.close().await.ok();
             }
         });
     }

crates/wzp-relay/src/room.rs

@@ -0,0 +1,200 @@
+//! Room management for multi-party calls.
+//!
+//! Each room holds N participants. When one participant sends a media packet,
+//! the relay forwards it to all other participants in the room (SFU model).
+
+use std::collections::HashMap;
+use std::sync::atomic::{AtomicU64, Ordering};
+use std::sync::Arc;
+
+use tokio::sync::Mutex;
+use tracing::{error, info};
+
+use wzp_proto::MediaTransport;
+
+/// Unique participant ID within a room.
+pub type ParticipantId = u64;
+
+static NEXT_PARTICIPANT_ID: AtomicU64 = AtomicU64::new(1);
+
+fn next_id() -> ParticipantId {
+    NEXT_PARTICIPANT_ID.fetch_add(1, Ordering::Relaxed)
+}
+
+/// A participant in a room.
+struct Participant {
+    id: ParticipantId,
+    addr: std::net::SocketAddr,
+    transport: Arc<wzp_transport::QuinnTransport>,
+}
+
+/// A room holding multiple participants.
+struct Room {
+    participants: Vec<Participant>,
+}
+
+impl Room {
+    fn new() -> Self {
+        Self {
+            participants: Vec::new(),
+        }
+    }
+
+    fn add(&mut self, addr: std::net::SocketAddr, transport: Arc<wzp_transport::QuinnTransport>) -> ParticipantId {
+        let id = next_id();
+        info!(room_size = self.participants.len() + 1, participant = id, %addr, "joined room");
+        self.participants.push(Participant { id, addr, transport });
+        id
+    }
+
+    fn remove(&mut self, id: ParticipantId) {
+        self.participants.retain(|p| p.id != id);
+        info!(room_size = self.participants.len(), participant = id, "left room");
+    }
+
+    fn others(&self, exclude_id: ParticipantId) -> Vec<Arc<wzp_transport::QuinnTransport>> {
+        self.participants
+            .iter()
+            .filter(|p| p.id != exclude_id)
+            .map(|p| p.transport.clone())
+            .collect()
+    }
+
+    fn is_empty(&self) -> bool {
+        self.participants.is_empty()
+    }
+
+    fn len(&self) -> usize {
+        self.participants.len()
+    }
+}
+
+/// Manages all rooms on the relay.
+pub struct RoomManager {
+    rooms: HashMap<String, Room>,
+}
+
+impl RoomManager {
+    pub fn new() -> Self {
+        Self {
+            rooms: HashMap::new(),
+        }
+    }
+
+    /// Join a room. Returns the participant ID.
+    pub fn join(
+        &mut self,
+        room_name: &str,
+        addr: std::net::SocketAddr,
+        transport: Arc<wzp_transport::QuinnTransport>,
+    ) -> ParticipantId {
+        let room = self.rooms.entry(room_name.to_string()).or_insert_with(Room::new);
+        room.add(addr, transport)
+    }
+
+    /// Leave a room. Removes the room if empty.
+    pub fn leave(&mut self, room_name: &str, participant_id: ParticipantId) {
+        if let Some(room) = self.rooms.get_mut(room_name) {
+            room.remove(participant_id);
+            if room.is_empty() {
+                self.rooms.remove(room_name);
+                info!(room = room_name, "room closed (empty)");
+            }
+        }
+    }
+
+    /// Get transports for all OTHER participants in a room.
+    pub fn others(
+        &self,
+        room_name: &str,
+        participant_id: ParticipantId,
+    ) -> Vec<Arc<wzp_transport::QuinnTransport>> {
+        self.rooms
+            .get(room_name)
+            .map(|r| r.others(participant_id))
+            .unwrap_or_default()
+    }
+
+    /// Get room size.
+    pub fn room_size(&self, room_name: &str) -> usize {
+        self.rooms.get(room_name).map(|r| r.len()).unwrap_or(0)
+    }
+
+    /// List all rooms with their sizes.
+    pub fn list(&self) -> Vec<(String, usize)> {
+        self.rooms.iter().map(|(k, v)| (k.clone(), v.len())).collect()
+    }
+}
+
+/// Run the receive loop for one participant in a room.
+/// Forwards all received packets to every other participant.
+pub async fn run_participant(
+    room_mgr: Arc<Mutex<RoomManager>>,
+    room_name: String,
+    participant_id: ParticipantId,
+    transport: Arc<wzp_transport::QuinnTransport>,
+) {
+    let addr = transport.connection().remote_address();
+    let mut packets_forwarded = 0u64;
+
+    loop {
+        let pkt = match transport.recv_media().await {
+            Ok(Some(pkt)) => pkt,
+            Ok(None) => {
+                info!(%addr, participant = participant_id, "disconnected");
+                break;
+            }
+            Err(e) => {
+                error!(%addr, participant = participant_id, "recv error: {e}");
+                break;
+            }
+        };
+
+        // Get current list of other participants
+        let others = {
+            let mgr = room_mgr.lock().await;
+            mgr.others(&room_name, participant_id)
+        };
+
+        // Forward to all others
+        for other in &others {
+            // Best-effort: if one send fails, continue to others
+            if let Err(e) = other.send_media(&pkt).await {
+                // Don't log every failure — they'll be cleaned up when their recv loop breaks
+                let _ = e;
+            }
+        }
+
+        packets_forwarded += 1;
+        if packets_forwarded % 500 == 0 {
+            let room_size = {
+                let mgr = room_mgr.lock().await;
+                mgr.room_size(&room_name)
+            };
+            info!(
+                room = %room_name,
+                participant = participant_id,
+                forwarded = packets_forwarded,
+                room_size,
+                "participant stats"
+            );
+        }
+    }
+
+    // Clean up
+    let mut mgr = room_mgr.lock().await;
+    mgr.leave(&room_name, participant_id);
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn room_join_leave() {
+        let mut mgr = RoomManager::new();
+        // Can't test with real transports, but test the room logic
+        assert_eq!(mgr.room_size("test"), 0);
+        assert!(mgr.list().is_empty());
+    }
+}

crates/wzp-web/src/main.rs

@@ -155,8 +155,10 @@ async fn handle_ws(socket: WebSocket, room: String, state: AppState) {
         Err(e) => { error!("create endpoint: {e}"); return; }
     };
 
+    // Pass room name as QUIC SNI so the relay knows which room to join
+    let sni = if room.is_empty() { "default" } else { &room };
     let connection =
-        match wzp_transport::connect(&endpoint, relay_addr, "localhost", client_config).await {
+        match wzp_transport::connect(&endpoint, relay_addr, sni, client_config).await {
             Ok(c) => c,
             Err(e) => { error!("connect to relay: {e}"); return; }
         };

crates/wzp-web/static/index.html

@@ -22,6 +22,11 @@
   .stats { margin-top: 0.5rem; font-size: 0.75rem; color: #555; font-family: monospace; }
   .level { margin-top: 1rem; height: 6px; background: #333; border-radius: 3px; overflow: hidden; }
   .level-bar { height: 100%; background: #00d4ff; width: 0%; transition: width 50ms; }
+  .controls { margin-top: 1rem; display: flex; gap: 0.5rem; justify-content: center; flex-wrap: wrap; }
+  .controls label { font-size: 0.8rem; color: #888; cursor: pointer; display: flex; align-items: center; gap: 0.3rem; }
+  .controls input[type="checkbox"] { accent-color: #00d4ff; }
+  #pttBtn { display: none; background: #444; color: #e0e0e0; border: 2px solid #666; padding: 0.8rem 2rem; font-size: 1rem; border-radius: 12px; cursor: pointer; user-select: none; -webkit-user-select: none; touch-action: none; }
+  #pttBtn.transmitting { background: #ff4444; border-color: #ff6666; color: white; }
 </style>
 </head>
 <body>
@@ -33,6 +38,10 @@
     <input type="text" id="room" placeholder="enter room name" value="">
   </div>
   <button id="callBtn" onclick="toggleCall()">Connect</button>
+  <div class="controls" id="controls" style="display:none;">
+    <label><input type="checkbox" id="pttMode" onchange="togglePTT()"> Radio mode (push-to-talk)</label>
+  </div>
+  <button id="pttBtn">Hold to Talk</button>
   <div class="level"><div class="level-bar" id="levelBar"></div></div>
   <div class="status" id="status"></div>
   <div class="stats" id="stats"></div>
@@ -48,6 +57,8 @@ let mediaStream = null;
 let captureNode = null;
 let playbackNode = null;
 let active = false;
+let transmitting = true; // in open-mic mode, always transmitting
+let pttMode = false;
 let framesSent = 0;
 let framesRecv = 0;
 let startTime = 0;
@@ -108,6 +119,7 @@ async function startCall() {
     framesSent = 0;
     framesRecv = 0;
     startTime = Date.now();
+    showControls(true);
     await startAudioCapture();
     await startAudioPlayback();
     startStatsUpdate();
@@ -142,6 +154,7 @@ function stopCall() {
   btn.textContent = 'Connect';
   btn.classList.remove('active');
   btn.disabled = false;
+  showControls(false);
   cleanupAudio();
   if (ws) { ws.close(); ws = null; }
   if (statsInterval) { clearInterval(statsInterval); statsInterval = null; }
@@ -163,8 +176,7 @@ async function startAudioCapture() {
     await audioCtx.audioWorklet.addModule('audio-processor.js');
     captureNode = new AudioWorkletNode(audioCtx, 'capture-processor');
     captureNode.port.onmessage = (e) => {
-      if (!active || !ws || ws.readyState !== WebSocket.OPEN) return;
-      // e.data is an ArrayBuffer of Int16 PCM
+      if (!active || !ws || ws.readyState !== WebSocket.OPEN || !transmitting) return;
       ws.send(e.data);
       framesSent++;
 
@@ -182,7 +194,7 @@ async function startAudioCapture() {
     captureNode = audioCtx.createScriptProcessor(1024, 1, 1);
     let acc = new Float32Array(0);
     captureNode.onaudioprocess = (ev) => {
-      if (!active || !ws || ws.readyState !== WebSocket.OPEN) return;
+      if (!active || !ws || ws.readyState !== WebSocket.OPEN || !transmitting) return;
       const input = ev.inputBuffer.getChannelData(0);
       const n = new Float32Array(acc.length + input.length);
       n.set(acc); n.set(input, acc.length); acc = n;
@@ -250,6 +262,55 @@ function startStatsUpdate() {
   }, 1000);
 }
 
+// --- Push-to-talk ---
+
+function togglePTT() {
+  pttMode = document.getElementById('pttMode').checked;
+  const btn = document.getElementById('pttBtn');
+  if (pttMode) {
+    transmitting = false;
+    btn.style.display = 'block';
+  } else {
+    transmitting = true;
+    btn.style.display = 'none';
+  }
+}
+
+// PTT button — hold to talk (mouse + touch)
+document.getElementById('pttBtn').addEventListener('mousedown', () => { startTransmit(); });
+document.getElementById('pttBtn').addEventListener('mouseup', () => { stopTransmit(); });
+document.getElementById('pttBtn').addEventListener('mouseleave', () => { stopTransmit(); });
+document.getElementById('pttBtn').addEventListener('touchstart', (e) => { e.preventDefault(); startTransmit(); });
+document.getElementById('pttBtn').addEventListener('touchend', (e) => { e.preventDefault(); stopTransmit(); });
+
+// Spacebar PTT
+document.addEventListener('keydown', (e) => { if (pttMode && active && e.code === 'Space' && !e.repeat) { e.preventDefault(); startTransmit(); } });
+document.addEventListener('keyup', (e) => { if (pttMode && active && e.code === 'Space') { e.preventDefault(); stopTransmit(); } });
+
+function startTransmit() {
+  if (!pttMode || !active) return;
+  transmitting = true;
+  document.getElementById('pttBtn').classList.add('transmitting');
+  document.getElementById('pttBtn').textContent = 'Transmitting...';
+}
+
+function stopTransmit() {
+  if (!pttMode) return;
+  transmitting = false;
+  document.getElementById('pttBtn').classList.remove('transmitting');
+  document.getElementById('pttBtn').textContent = 'Hold to Talk';
+}
+
+// Show controls when connected
+function showControls(show) {
+  document.getElementById('controls').style.display = show ? 'flex' : 'none';
+  if (!show) {
+    document.getElementById('pttBtn').style.display = 'none';
+    pttMode = false;
+    transmitting = true;
+  }
+}
+
 // Set room from URL on load
 window.addEventListener('load', () => {
   const room = getRoom();