Improve handling of timeouts when federates connect to RTI/each other

core/federated/federate.c

@@ -1678,15 +1678,14 @@ void lf_terminate_execution(environment_t* env) {
 
 void lf_connect_to_federate(uint16_t remote_federate_id) {
   int result = -1;
-  int count_retries = 0;
 
   // Ask the RTI for port number of the remote federate.
   // The buffer is used for both sending and receiving replies.
   // The size is what is needed for receiving replies.
   unsigned char buffer[sizeof(int32_t) + INET_ADDRSTRLEN + 1];
   int port = -1;
   struct in_addr host_ip_addr;
-  int count_tries = 0;
+  instant_t start_connect = lf_time_physical();
   while (port == -1 && !_lf_termination_executed) {
     buffer[0] = MSG_TYPE_ADDRESS_QUERY;
     // NOTE: Sending messages in little endian.
@@ -1724,7 +1723,7 @@ void lf_connect_to_federate(uint16_t remote_federate_id) {
     // remote federate has not yet sent an MSG_TYPE_ADDRESS_ADVERTISEMENT message to the RTI.
     // Sleep for some time before retrying.
     if (port == -1) {
-      if (count_tries++ >= CONNECT_MAX_RETRIES) {
+      if (CHECK_TIMEOUT(start_connect, CONNECT_TIMEOUT)) {
         lf_print_error_and_exit("TIMEOUT obtaining IP/port for federate %d from the RTI.", remote_federate_id);
       }
       // Wait ADDRESS_QUERY_RETRY_INTERVAL nanoseconds.
@@ -1745,8 +1744,8 @@ void lf_connect_to_federate(uint16_t remote_federate_id) {
   LF_PRINT_LOG("Received address %s port %d for federate %d from RTI.", hostname, uport, remote_federate_id);
 #endif
 
-  // Iterate until we either successfully connect or exceed the number of
-  // attempts given by CONNECT_MAX_RETRIES.
+  // Iterate until we either successfully connect or we exceed the CONNECT_TIMEOUT
+  start_connect = lf_time_physical();
   int socket_id = -1;
   while (result < 0 && !_lf_termination_executed) {
     // Create an IPv4 socket for TCP (not UDP) communication over IP (0).
@@ -1772,12 +1771,11 @@ void lf_connect_to_federate(uint16_t remote_federate_id) {
       // Note that this should not really happen since the remote federate should be
       // accepting socket connections. But possibly it will be busy (in process of accepting
       // another socket connection?). Hence, we retry.
-      count_retries++;
-      if (count_retries > CONNECT_MAX_RETRIES) {
-        // If the remote federate is not accepting the connection after CONNECT_MAX_RETRIES
+      if (CHECK_TIMEOUT(start_connect, CONNECT_TIMEOUT)) {
+        // If the remote federate is not accepting the connection after CONNECT_TIMEOUT
         // treat it as a soft error condition and return.
-        lf_print_error("Failed to connect to federate %d after %d retries. Giving up.", remote_federate_id,
-                       CONNECT_MAX_RETRIES);
+        lf_print_error("Failed to connect to federate %d with timeout: " PRINTF_TIME ". Giving up.", remote_federate_id,
+                       CONNECT_TIMEOUT);
         return;
       }
       lf_print_warning("Could not connect to federate %d. Will try again every" PRINTF_TIME "nanoseconds.\n",
@@ -1859,10 +1857,10 @@ void lf_connect_to_rti(const char* hostname, int port) {
   _fed.socket_TCP_RTI = create_real_time_tcp_socket_errexit();
 
   int result = -1;
-  int count_retries = 0;
   struct addrinfo* res = NULL;
 
-  while (count_retries++ < CONNECT_MAX_RETRIES && !_lf_termination_executed) {
+  instant_t start_connect = lf_time_physical();
+  while (!CHECK_TIMEOUT(start_connect, CONNECT_TIMEOUT) && !_lf_termination_executed) {
     if (res != NULL) {
       // This is a repeated attempt.
       if (_fed.socket_TCP_RTI >= 0)
@@ -1884,7 +1882,7 @@ void lf_connect_to_rti(const char* hostname, int port) {
         // Reconstruct the address info.
         rti_address(hostname, uport, &res);
       }
-      lf_print("Trying RTI again on port %d (attempt %d).", uport, count_retries);
+      lf_print("Trying RTI again on port %d.", uport);
     } else {
       // This is the first attempt.
       rti_address(hostname, uport, &res);
@@ -1975,7 +1973,7 @@ void lf_connect_to_rti(const char* hostname, int port) {
     }
   }
   if (result < 0) {
-    lf_print_error_and_exit("Failed to connect to RTI after %d tries.", CONNECT_MAX_RETRIES);
+    lf_print_error_and_exit("Failed to connect to RTI with timeout: " PRINTF_TIME, CONNECT_TIMEOUT);
   }
 
   freeaddrinfo(res); /* No longer needed */

include/core/federated/federate.h

@@ -244,7 +244,7 @@ void lf_connect_to_federate(uint16_t);
  * This will return the socket descriptor for the connection.
  * If port_number is 0, then start at DEFAULT_PORT and increment
  * the port number on each attempt. If an attempt fails, wait CONNECT_RETRY_INTERVAL
- * and try again.  If it fails after CONNECT_MAX_RETRIES, the program exits.
+ * and try again.  If it fails after CONNECT_TIMEOUT, the program exits.
  * If it succeeds, it sets the _fed.socket_TCP_RTI global variable to refer to
  * the socket for communicating with the RTI.
  * @param hostname A hostname, such as "localhost".

include/core/federated/network/net_common.h

@@ -205,10 +205,10 @@ THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 /**
  * Bound on the number of retries to connect to the RTI.
- * A federate will retry every CONNECT_RETRY_INTERVAL seconds
- * this many times before giving up.
+ * A federate will retry every CONNECT_RETRY_INTERVAL seconds until
+ * CONNECTION_TIMEOUT expires.
  */
-#define CONNECT_MAX_RETRIES 100
+#define CONNECT_TIMEOUT MINUTES(1)
 
 /**
  * Maximum number of port addresses that a federate will try to connect to the RTI on.

tag/api/tag.h

@@ -47,6 +47,9 @@
 #define ZERO_TAG                                                                                                       \
   (tag_t) { .time = 0LL, .microstep = 0u }
 
+// Returns true if timeout has elapsed.
+#define CHECK_TIMEOUT(start, duration) (lf_time_physical() > ((start) + (duration)))
+
 // Convenience for converting times
 #define BILLION ((instant_t)1000000000LL)