libdeng2|Fixed: Allow multiple Beacons to coexist on one machine

Each server will listen on its own UDP port. The default range of UDP ports that local servers use is 13209..13224 (16 ports).
skyjake · Feb 12, 2013 · 6fd78c8 · 6fd78c8
1 parent 774461d
commit 6fd78c8
Show file tree

Hide file tree

Showing 2 changed files with 33 additions and 7 deletions.
diff --git a/doomsday/libdeng2/include/de/net/beacon.h b/doomsday/libdeng2/include/de/net/beacon.h
@@ -43,6 +43,12 @@ class DENG2_PUBLIC Beacon : public QObject
 
     virtual ~Beacon();
 
+    /**
+     * Port the beacon uses for listening.
+     * @return  Port.
+     */
+    duint16 port() const;
+
     /**
      * Starts the beacon with a message to give out.
      *

diff --git a/doomsday/libdeng2/src/net/beacon.cpp b/doomsday/libdeng2/src/net/beacon.cpp
@@ -27,6 +27,12 @@
 
 namespace de {
 
+/**
+ * Maximum number of Beacon UDP ports in simultaneous use at one machine, i.e.,
+ * maximum number of servers on one machine.
+ */
+static duint16 const MAX_LISTEN_RANGE = 16;
+
 static char const *discoveryMessage = "Doomsday Beacon 1.0";
 
 struct Beacon::Instance
@@ -59,6 +65,11 @@ Beacon::~Beacon()
     delete d;
 }
 
+duint16 Beacon::port() const
+{
+    return d->port;
+}
+
 void Beacon::start(duint16 serviceListenPort)
 {
     DENG2_ASSERT(!d->socket);
@@ -68,11 +79,17 @@ void Beacon::start(duint16 serviceListenPort)
     d->socket = new QUdpSocket;
     connect(d->socket, SIGNAL(readyRead()), this, SLOT(readIncoming()));
 
-    if(!d->socket->bind(d->port, QUdpSocket::ShareAddress))
+    for(duint16 attempt = 0; attempt < MAX_LISTEN_RANGE; ++attempt)
     {
-        /// @throws PortError Could not open the UDP port.
-        throw PortError("Beacon::start", "Could not bind to UDP port " + String::number(d->port));
+        if(d->socket->bind(d->port + attempt, QUdpSocket::DontShareAddress))
+        {
+            d->port = d->port + attempt;
+            return;
+        }
     }
+
+    /// @throws PortError Could not open the UDP port.
+    throw PortError("Beacon::start", "Could not bind to UDP port " + String::number(d->port));
 }
 
 void Beacon::setMessage(IByteArray const &advertisedMessage)
@@ -222,10 +239,13 @@ void Beacon::continueDiscovery()
 
     LOG_TRACE("Broadcasting %i bytes") << block.size();
 
-    // Send a new broadcast.
-    d->socket->writeDatagram(block,
-                             QHostAddress::Broadcast,
-                             d->port);
+    // Send a new broadcast to the whole listening range of the beacons.
+    for(duint16 range = 0; range < MAX_LISTEN_RANGE; ++range)
+    {
+        d->socket->writeDatagram(block,
+                                 QHostAddress::Broadcast,
+                                 d->port + range);
+    }
 }
 
 } // namespace de