Add server-side NOOP upload for connection keepalive

src/Cedar/Protocol.c

@@ -5429,7 +5429,7 @@ void ClientUploadNoop(CONNECTION *c)
 	}
 
 	p = PackError(0);
-	PackAddInt(p, "noop", 1);
+	PackAddInt(p, "noop", NOOP);
 	(void)HttpClientSend(c->FirstSock, p);
 	FreePack(p);
 
@@ -5440,6 +5440,24 @@ void ClientUploadNoop(CONNECTION *c)
 	}
 }
 
+void ServerUploadNoop(CONNECTION *c)
+{
+	PACK *p;
+	// Validate arguments
+	if (c == NULL)
+	{
+		return;
+	}
+
+	p = PackError(0);
+	PackAddInt(p, "noop", NOOP_IGNORE);
+	(void)HttpServerSend(c->FirstSock, p);
+	FreePack(p);
+
+	// Client can't re-respond to an HTTP "response" 
+	// so we don't wait for it on the server side
+}
+
 // Add client version information to the PACK
 void PackAddClientVersion(PACK *p, CONNECTION *c)
 {

src/Cedar/Protocol.h

@@ -169,6 +169,7 @@ bool GetSessionKeyFromPack(PACK *p, UCHAR *session_key, UINT *session_key_32);
 void CreateNodeInfo(NODE_INFO *info, CONNECTION *c);
 UINT SecureSign(SECURE_SIGN *sign, UINT device_id, char *pin);
 void ClientUploadNoop(CONNECTION *c);
+void ServerUploadNoop(CONNECTION *c);
 bool ClientCheckServerCert(CONNECTION *c, bool *expired);
 void ClientCheckServerCertThread(THREAD *thread, void *param);
 bool ClientSecureSign(CONNECTION *c, UCHAR *sign, UCHAR *random, X **x);