FRRouting Topology Tests with Mininet

Guidelines

Instructions for use, write or debug topologies can be found in the guidelines. To learn/remember common code snippets see here.

Before creating a new topology, make sure that there isn't one already that does what you need. If nothing is similar, then you may create a new topology, preferably, using the newest template.

Installation of Mininet for running tests

Only tested with Ubuntu 16.04 (which uses Mininet 2.2.0)

Instructions are the same for all setups (ie ExaBGP is only used for BGP tests)

Installing Mininet Infrastructure:

1. apt-get install mininet
2. apt-get install python-pip
3. apt-get install iproute
4. pip install ipaddr
5. pip install pytest
6. pip install exabgp==3.4.17 (Newer 4.0 version of exabgp is not yet supported)
7. useradd -d /var/run/exabgp/ -s /bin/false exabgp

Enable Coredumps

Optional, will give better output

1. apt-get install gdb

2. disable apport (which move core files)

   Set enabled=0 in /etc/default/apport

3. Update security limits

   Add/change /etc/security/limits.conf to

    #<domain>      <type>  <item>         <value>
    *               soft    core          unlimited
    root            soft    core          unlimited
    *               hard    core          unlimited
    root            hard    core          unlimited
   

4. reboot (for options to take effect)

FRRouting (FRR) Installation

FRR needs to be installed separatly. It is assume to be configured like the standard Ubuntu Packages:

• Binaries in /usr/lib/frr
• State Directory /var/run/frr
• Running under user frr, group frr
• vtygroup: frrvty
• config directory: /etc/frr
• For FRR Packages, install the dbg package as well for coredump decoding

No FRR config needs to be done and no FRR daemons should be run ahead of the test. They are all started as part of the test

Manual FRRouting (FRR) build

If you prefer to manually build FRR, then use the following suggested config:

./configure \
	--prefix=/usr \
	--localstatedir=/var/run/frr \
	--sbindir=/usr/lib/frr \
	--sysconfdir=/etc/frr \
	--enable-vtysh \
	--enable-pimd \
	--enable-multipath=64 \
	--enable-user=frr \
	--enable-group=frr \
	--enable-vty-group=frrvty \
	--with-pkg-extra-version=-my-manual-build

And create frr User and frrvty group as follows:

addgroup --system --gid 92 frr
addgroup --system --gid 85 frrvty
adduser --system --ingroup frr --home /var/run/frr/ \
   --gecos "FRRouting suite" --shell /bin/false frr
usermod -G frrvty frr

Executing Tests

Execute all tests with output to console

py.test -s -v --tb=no

All test_* scripts in subdirectories are detected and executed (unless disabled in pytest.ini file)

--tb=no disables the python traceback which might be irrelevant unless the test script itself is debugged

Execute single test

cd test_to_be_run
./test_to_be_run.py

For further options, refer to pytest documentation

Test will set exit code which can be used with git bisect

For the simulated topology, see the description in the python file

If you need to clear the mininet setup between tests (if it isn't cleanly shutdown), then use the mn -c command to clean up the environment

(Optional) StdErr log from daemos after exit

To enable the reporting of any messages seen on StdErr after the daemons exit, the following env variable can be set.

export TOPOTESTS_CHECK_STDERR=Yes

(The value doesn't matter at this time. The check is if the env variable exists or not) There is no pass/fail on this reporting. The Output will be reported to the console

export TOPOTESTS_CHECK_MEMLEAK="/home/mydir/memleak_"

This will enable the check and output to console and the writing of the information to files with the given prefix (followed by testname), ie /home/mydir/memcheck_test_bgp_multiview_topo1.txt in case of a memory leak.

(Optional) Collect Memory Leak Information

FreeRangeRouting processes have the capabilities to report remaining memory allocations upon exit. To enable the reporting of the memory, define an enviroment variable TOPOTESTS_CHECK_MEMLEAK with the file prefix, ie

export TOPOTESTS_CHECK_MEMLEAK="/home/mydir/memleak_"

This will enable the check and output to console and the writing of the information to files with the given prefix (followed by testname), ie /home/mydir/memcheck_test_bgp_multiview_topo1.txt in case of a memory leak.

(Optional) Run topotests with GCC AddressSanitizer enabled

Topotests can be run with the GCC AddressSanitizer. It requires GCC 4.8 or newer. (Ubuntu 16.04 as suggested here is fine with GCC 5 as default) For more information on AddressSanitizer, see https://github.com/google/sanitizers/wiki/AddressSanitizer

The checks are done automatically in the library call of checkRouterRunning (ie at beginning of tests when there is a check for all daemons running). No changes or extra configuration for topotests is required beside compiling the suite with AddressSanitizer enabled.

If a daemon crashed, then the errorlog is checked for AddressSanitizer output. If found, then this is added with context (calling test) to /tmp/AddressSanitizer.txt in markdown compatible format.

Compiling for GCC AddressSanitizer requires to use gcc as a linker as well (instead of ld). Here is a suggest way to compile frr with AddressSanitizer for stable/3.0 branch:

git clone https://github.com/FRRouting/frr.git
cd frr
git checkout stable/3.0
./bootstrap.sh
export CC=gcc
export CFLAGS="-O1 -g -fsanitize=address -fno-omit-frame-pointer"
export LD=gcc
export LDFLAGS="-g -fsanitize=address -ldl"
./configure --enable-shared=no \
	--prefix=/usr/lib/frr --sysconfdir=/etc/frr \
	--localstatedir=/var/run/frr \
	--sbindir=/usr/lib/frr --bindir=/usr/lib/frr \
	--enable-exampledir=/usr/lib/frr/examples \
	--with-moduledir=/usr/lib/frr/modules \
	--enable-multipath=0 --enable-rtadv \
	--enable-tcp-zebra --enable-fpm --enable-pimd
make
sudo make install
# Create symlink for vtysh, so topotest finds it in /usr/lib/frr
sudo ln -s /usr/lib/frr/vtysh /usr/bin/

and create frr user and frrvty group as shown above

License

All the configs and scripts are licensed under a ISC-style license. See Python scripts for details.