Ostinato is an open-source, cross-platform packet/traffic generator and analyzer with a friendly GUI. It aims to be “Wireshark in Reverse” and thus become complementary to Wireshark.
You can download it from the following link: https://packetstormsecurity.com/files/download/96622/ostinato-src-0.3.tar.gz
Source: https://packetstormsecurity.com/files/96622/Ostinato-Traffic-Generator-0.3-Source-Code.html