Avoid starvation

src/lib/udp/server.cpp

@@ -27,8 +27,7 @@ UdpServer::UdpServer(const std::string &address, uint16_t port): sockets{}
 
 int UdpServer::Receive(uint8_t *buffer, size_t bufferSize, int timeoutMs, InetAddress &outPeerAddress)
 {
-    // Use the first socket ready for receiving data
-    // Warning: this may lead to starvation since there is no round robin implemented yet in `Socket::Select`
+    // Choose at random a ready socket for receiving data
     std::vector<Socket> ws;
     return Socket::Select(sockets, ws, timeoutMs).receive(buffer, bufferSize, 0, outPeerAddress);
 }

src/utils/network.cpp

@@ -13,6 +13,7 @@
 
 #include <arpa/inet.h>
 #include <netdb.h>
+#include <random>
 #include <stdexcept>
 #include <sys/socket.h>
 #include <sys/types.h>
@@ -273,10 +274,20 @@ Socket Socket::Select(const std::vector<Socket> &readSockets, const std::vector<
     std::vector<Socket> rs, ws;
     Select(readSockets, writeSockets, rs, ws, timeout);
 
+    // Return a socket choosen at random from selection
+    // to avoid starvation
+    std::default_random_engine generator;
+
     if (!rs.empty())
-        return rs[0];
+    {
+        std::uniform_int_distribution<int> drs(0, rs.size()-1);
+        return rs[drs(generator)];
+    }
     if (!ws.empty())
-        return rs[0];
+    {
+        std::uniform_int_distribution<int> dws(0, ws.size()-1);
+        return rs[dws(generator)];
+    }
     return {};
 }