add: relay/piface support

include/helpers.h

@@ -0,0 +1,25 @@
+#ifndef CONTROLLER_HELPERS_H
+#define CONTROLLER_HELPERS_H
+
+int
+helper_connect_tcp_server(char* host, uint16_t port);
+
+int
+helper_bind_tcp_server(char* addr, uint16_t port, int max_client_backlog);
+
+uint16_t
+helper_get_port(int sock);
+
+/**
+ * @brief Open socket for discovery
+ *
+ * Will exit program when unable to open socket.
+ *
+ * @param discovery_port Port number to listen on for discovery broadcasts
+ *
+ * @return Open socket to accept discovery broadcasts on
+ */
+int
+helper_open_discovery_socket(uint16_t discovery_port);
+
+#endif /* CONTROLLER_HELPERS_H */