Don't work too much

src/main.c

@@ -1433,7 +1433,6 @@ int main (int argc, char **argv)
                 }
             }
 
-            while (1) {
             buffer_shift(&tun.write);
 
             if _0_(gt_decrypt(&ctx, &tun.write, &sock.read)) {
@@ -1441,6 +1440,7 @@ int main (int argc, char **argv)
                 goto restart;
             }
 
+            while (1) {
                 size_t size = buffer_read_size(&tun.write);
 
                 if (!size)