Ethloop

Ethloop is very simple and versatile packet generator and measurer which I use to test HTB qdisc. It is developement tool and you take it as such. It accepts controling program at stdin, executing it and producing flow rate table at stdout.

The generated rate is output on interface(s) selected in program and data are recieved on all interfaces in a system. You sometimes need to set promisc flag on recieving interfaces.
Generated packets are ethernet frames with protocol set to ETH_P_CUST so that you can safely inject them into existing LANs. MAC addresses are set to MACs of sending/recieving interface (may be the same).

The controling program is line based text file. Each line has fixed format and comment lines behins with #. The format of a line is:
5000 R 2 4500000

Number of spaces is optional and tabs can be used. Input is parsed by sscanf "%u %c %u %n". The first number is time in miliseconds from program start. The second character determines operation to do. Third number is flow id (see below) and remainder of line is operation dependent. However the remainder can be text or number and numbers are allowed in decimal or hex (if starting with 0x). Number can end with k to multiply it by 1024.

The line above means: at time 5sec set rate of flow 2 to 4.5 MBps. Lines are first read into struct progdata in memory (performance reasons) and should be in increasing time order. Ethloop performs no sorting by time so be carefull about it. Each line is executed at its time and can change ongoing traffic generators.