Patch from Jeff Studer <jstuder@aquilagroup.com> to supply a defaults for

localfilename from remotefilename, and for remotefilename from localfilename
when the other one is not supplied.

networking/tftp.c

@@ -548,6 +548,13 @@ int tftp_main(int argc, char **argv)
 	if ((cmd == 0) || (optind == argc)) {
 		show_usage();
 	}
+	if(cmd == tftp_cmd_get)
+	    if(localfile == NULL)
+		localfile = remotefile;
+
+	if(cmd == tftp_cmd_put)
+	    if(remotefile == NULL)
+		remotefile = localfile;
 
 	fd = open(localfile, flags, 0644);
 	if (fd < 0) {