add retry logic

- if the connection to server fails, retry 5 times, sleeping 5 seconds before
  each retry.
- if the redirection fails, go back and request the chunk from the server again.

src/main.c

@@ -54,6 +54,7 @@ struct tip_client {
 	uint64_t data_len;
 	uint64_t content_len;
 	int state;
+	int num_retries;
 	int fd;
 	bool error;
 	bool redirected;
@@ -444,6 +445,9 @@ static uint32_t select_file_chunk(bool *file_chunk)
 
 static char _filename[PATH_MAX + 1];
 
+#define MAX_RETRIES	5
+#define WAIT_RETRY	5	/* wait 5 seconds before retrying. */
+
 int main(int argc, char *argv[])
 {
 	struct timeval tv_start, tv_stop, tv;
@@ -471,7 +475,7 @@ int main(int argc, char *argv[])
 		k = select_file_chunk(file_chunk);
 		snprintf(_filename, sizeof(_filename), "%s.%u", argv[2], k);
 		filename = _filename;
-
+retry:
 		syslog(LOG_INFO, "Requesting file %s to server\n", filename);
 
 		tip_client_connect(argv[1]);
@@ -482,7 +486,14 @@ int main(int argc, char *argv[])
 
 		if (_cli.error) {
 			syslog(LOG_ERR, "Failed to fetch file %s\n", filename);
-			break;
+			sleep(WAIT_RETRY);
+			if (_cli.num_retries++ >= MAX_RETRIES) {
+				syslog(LOG_ERR, "Maximum number of retries (%d), bailing out!\n",
+				       MAX_RETRIES);
+				break;
+			}
+			_cli.error = false;
+			goto retry;
 		}
 
 		tip_client_progress(&_cli, true);