| libnl@d21790bf96 | ||
| .gitignore | ||
| config.h | ||
| dist.c | ||
| dump.sh | ||
| emulate.c | ||
| hist.c | ||
| hist.h | ||
| main.c | ||
| Makefile | ||
| mark.c | ||
| probe.c | ||
| README.md | ||
| tc.c | ||
| tc.h | ||
| tcp.c | ||
| tcp.h | ||
| timing.c | ||
| timing.h | ||
| ts.c | ||
| ts.h | ||
| utils.c | ||
| utils.h | ||
Netem Tool
This tool uses the 3-way TCP handshake to measure the real RTT of a TCP connection.
Usage
Use case 1: collect probing measurements
Run TCP SYN/ACK probes to measure round-trip-time (RTT):
./netem probe 8.8.8.8 > probing.dat
Use case 2: convert measurements into delay distribution table
Collect measurements to build a tc-netem(8) delay distribution table
Use case 3
The output of this command and be stored in a file or directly passed to the emulate subcommand:
./netem probe 8.8.8.8 | ./netem emulate
./netem emulate < probing.dat
To apply the network emulation only to a limit stream of packets, you can use the mark tool:
sudo LD_PRELOAD=${PWD}/mark.so MARK=0xCD ping google.de
Please make sure the specify the environmental variables after the sudo command!
This is necessary, as ping is a SUID program.
The dynamic linker strips certain enviromental variables (as LD_PRELOAD) for security reasons!
Building
Install libnl
git submodule init git submodule update
cd libnl/ autreconf -i ./configure make make install
Install netem
Just run make.
Dependencies
- libnl3 (3.2.26)
- recent Linux Kernel version
For building libnl (make libnl)
- libtool
- bison
- flex
- autotools
See also
- http://www.infradead.org/~tgr/libnl/
- https://www.kernel.org/doc/Documentation/networking/timestamping.txt
- https://github.com/shemminger/iproute2/tree/master/netem
- tc-netem(8)
Author
Steffen Vogel post@steffenvogel.de
This tool was developed as a project for the Network Programming Laboratory of the Institute for Networked Systems, RWTH Aachen University, in summer 2015.
License
Copyright (C) 2015 Steffen Vogel
This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or any later version.
This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
You should have received a copy of the GNU General Public License along with this program. If not, see http://www.gnu.org/licenses/.