[email protected] 2009-06-02

1. Netqos

Netqos is a virtual device for 2.6 linux kernels.

2. External data is needed to compile and test!

That's right, you will need about 1,5 GB of external data to compile and test netqos the way I do it. Of course none of these external data is included in this distribution. You will have to get it yourself. That way I keep this distribution small and avoid the inclusion of external software.

2.1 What external data I need and how do I get it?

To compile netqos you will need a full kernel source tree.

To test netqos the way I do it, you will need an UML kernel and some root filesystems to boot it.

I have write some scripts to help you/me to get all these things. They are under the extdata-generator/ directory. You will need to edit the extdata-generator/CONFIGUREME file before executing those scritps. Then just execute each of the scripts in alphanumerical order.

If you are trying to compile an older kernel in some new distributions you will also need to copy /usr/include/sys/user.h to /usr/include/asm/user.h.

3. Kernel tree compilation

The scripts to download and compile a kernel are:

extdata-generator/00-download-kernel-tree.sh
extdata-generator/01-compile-uml-kernel.sh

To compile a 2.6 linux kernel module you will need a compiled linux kernel source tree. I'm going to use UML as the compilation architecture as the testing and debugging of the kernel module is safer and easier.

When configuring the kernel compilation remember to adapt it to your CPU and to include hostfs support. Also remember to include all the debugging options you need; some of the following wil be usefull:

CONFIG_DEBUG_KERNEL CONFIG_DEBUG_SLAB CONFIG_DEBUG_PAGEALLOC CONFIG_DEBUG_SPINLOCK CONFIG_DEBUG_SPINLOCK_SLEEP CONFIG_INIT_DEBUG CONFIG_DEBUG_INFO CONFIG_MAGIC_SYSRQ CONFIG_DEBUG_STACKOVERFLOW CONFIG_DEBUG_STACK_USAGE CONFIG_KALLSYMS CONFIG_IKCONFIG CONFIG_IKCONFIG_PROC CONFIG_ACPI_DEBUG CONFIG_DEBUG_DRIVER CONFIG_SCSI_CONSTANTS CONFIG_PROFILING

See doc/uml-compilation.txt for instructions about how to compile such a kernel. If you edit the CONFIGUREME file and used my extdata-generator/ scripts to generate all the needed external data, you will only need to invoke "make" to compile the module.

4. Test the module

4.1 UML rootfs creation

See doc/01-uml-rootfs-creation.txt for instruction about how to create the rootfs for the UML systems. If you used my extdata-generator/ scripts you have already create a working rootfs.

4.2 Launch the rootfs

Just launch it with the newly generated "rootfs/run-uml.sh". There is only one user "root" with no passwd.

4.3 Test the module

You will find the module and the load and unload scripts at:

/mnt/host-tmp/netqos.ko /mnt/host-tmp/netqos_load /mnt/host-tmp/netqos_unload

Use one of the UML terminals to monitor kernels logs:

; tail -f /var/log/kern.log | egrep -v "IRQ 10/winch|Failed to open console|getmaster - no usable host pty"

Use the other terminal to play with the module:

client:~# cd /mnt/host-tmp client:/mnt/host-tmp# modinfo netqos.ko filename: netqos.ko version: 0.2 author: Alberto Cortes [email protected] license: GPL srcversion: E325E0C32CA0B0CEDE2D5BB depends:
vermagic: 2.6.29.4 mod_unload client:/mnt/host-tmp# netqos_load client:/mnt/host-tmp# tree /sys/kernel/netqos/ /sys/kernel/netqos/ |-- figures | |-- bw | |-- delay | |-- jitter | -- price |-- ifaces -- version

6 directories, 1 file client:/mnt/host-tmp# netqos_test all tests OK client:/mnt/host-tmp# netqos_unload