From 5a79899d5a888e9aa76f29cb889e77979062a4a1 Mon Sep 17 00:00:00 2001
From: Mikko Rasa <tdb@tdb.fi>
Date: Thu, 15 Oct 2015 02:49:29 +0300
Subject: [PATCH] Use a datagram socket for automatic service discovery

---
 source/networkinterface.cpp | 16 ++++++++++++++++
 source/networkinterface.h   |  3 +++
 2 files changed, 19 insertions(+)

diff --git a/source/networkinterface.cpp b/source/networkinterface.cpp
index 74c80dc..1bf7b4a 100644
--- a/source/networkinterface.cpp
+++ b/source/networkinterface.cpp
@@ -6,17 +6,23 @@
 using namespace std;
 using namespace Msp;
 
+#include <msp/io/print.h>
+
 NetworkInterface::NetworkInterface(Xinema &x):
 	xinema(x)
 {
 	Net::SockAddr *addr = Net::resolve("::", "34588", Net::INET6);
 	server_sock = new Net::StreamServerSocket(addr->get_family());
 	server_sock->listen(*addr);
+	discover_sock = new Net::DatagramSocket(addr->get_family());
+	discover_sock->bind(*addr);
 	delete addr;
 
 	server_sock->signal_data_available.connect(sigc::mem_fun(this, &NetworkInterface::connection_available));
+	discover_sock->signal_data_available.connect(sigc::mem_fun(this, &NetworkInterface::discover_request));
 
 	event_disp.add(*server_sock);
+	event_disp.add(*discover_sock);
 
 	thread = new NetworkThread(*this);
 }
@@ -35,6 +41,16 @@ void NetworkInterface::connection_available()
 	clients.push_back(new Client(xinema, sock));
 }
 
+void NetworkInterface::discover_request()
+{
+	Net::SockAddr *peer_addr;
+	char rbuf[1024];
+	discover_sock->recvfrom(rbuf, sizeof(rbuf), peer_addr);
+	IO::print("Discovery beacon received from %s\n", peer_addr->str());
+	discover_sock->sendto("xinema", 6, *peer_addr);
+	delete peer_addr;
+}
+
 
 NetworkInterface::NetworkThread::NetworkThread(NetworkInterface &n):
 	network(n),
diff --git a/source/networkinterface.h b/source/networkinterface.h
index fbb66b9..9814f6a 100644
--- a/source/networkinterface.h
+++ b/source/networkinterface.h
@@ -4,6 +4,7 @@
 #include <msp/core/thread.h>
 #include <msp/io/eventdispatcher.h>
 #include <msp/io/pipe.h>
+#include <msp/net/datagramsocket.h>
 #include <msp/net/streamserversocket.h>
 
 class Client;
@@ -30,6 +31,7 @@ private:
 
 	Xinema &xinema;
 	Msp::Net::StreamServerSocket *server_sock;
+	Msp::Net::DatagramSocket *discover_sock;
 	Msp::IO::EventDispatcher event_disp;
 	NetworkThread *thread;
 	std::list<Client *> clients;
@@ -40,6 +42,7 @@ public:
 
 private:
 	void connection_available();
+	void discover_request();
 };
 
 #endif
-- 
2.43.0