How to add .o file in the Linux Kernel
I would like to know how would you enable the Congestion Control Algorithm correctly (lets call it Tcp_quic or quic).
My code is almost exactly like the tcp_veno.c file. Just the algorithm in the tcp_veno_cong_avoid() function changed.
I would like to attached the code on here, but I got an upload error. I would post it as well, but it is pretty long.
I have successfully compile the Linux Kernel with the C file (in the directory linux-3.4-rc7\net\ipv4\tcp_quic.c)
I just need to enable it, so I can use my algorithm and add it to the Kernel.
I realize that in the Linux Kernel folder(kernel\linux-3.3.6\net\ipv4), where I added the tcp_quic.c file, does not have .mod.o or .o file. With means that the tcp_quic.c did not compile successfully, right? However why did the compile in the terminal compile successfully? I read on one forum that may be I need to change something in the MAKEFILE to have .o file, is this true? I am not sure how I would do this if it is so.
I know that most people said that you should not mess with the Kernel, but it is something I would like to try.
The code below is how I want to enable the Congestion Control Algorithm.
Code:
echo quic > /proc/sys/net/ipv4/tcp_congestion_control
Also this is how I compile the Linux Kernel:
Code:
make-kpkg clean
fakeroot make-kpkg --initrd --append-to-version=-geekernel kernel_image kernel_headers
(this takes about 2 hours to compile)
Re: How to add .o file in the Linux Kernel
Yes, you'd need to modify the Makefile in net/ipv4/.
In there, just look for tcp_veno.o - how it's getting used.
More precisely, check these:
http://lxr.linux.no/linux+*/net/ipv4/Makefile#L46
http://lxr.linux.no/linux+*/net/ipv4/Kconfig#L530
You'd need to add something similar for your files.
If you want to compile it as a module, use the following command while compiling the kernel:
Code:
fakeroot CONFIG_TCP_CONG_WHATEVER=m make-kpkg --initrd --append-to-version=-geekernel kernel_image kernel_headers
where you add the following line in the Makefile:
Code:
obj-$(CONFIG_TCP_CONG_WHATEVER) += tcp_<your_file>.o
Re: How to add .o file in the Linux Kernel
the_unforgiven,
Thank you for the reply.
So far I have done that steps on editing the MAKEFILE and the Kconfig file. Where I see veno, I copy and paste another line(s) of code and replace it with the word "quic".
What I put in the MAKEFILE is
Code:
obj-$(CONFIG_TCP_CONG_QUIC) += tcp_quic.o
What I put in the Kconfig file is:
(there is a lot of editing in this one I wont list them because I basically search for "vegas/veno" to copy and paste a new one for "quic"
I did get an error when I try using the code you have recommended, but I got an Error
Code:
fakeroot CONFIG_TCP_CONG_QUIC=m make-kpkg --initrd --append-to-version=-geekernel kernel_image kernel_headers
This is the error
Quote:
/usr/bin/fakeroot: line 176: CONFIG_TCP_QUIC=m: command not found
Here is the code in the fakeroot file around line 176:
Code:
export FAKEROOT_FD_BASE
if test -z "$*"; then
FAKEROOTKEY=$FAKEROOTKEY LD_LIBRARY_PATH="$PATHS" LD_PRELOAD="$LIB" ${SHELL:-/bin/sh}
RESULT=$?
else
(LINE 176) FAKEROOTKEY=$FAKEROOTKEY LD_LIBRARY_PATH="$PATHS" LD_PRELOAD="$LIB" "$@"
RESULT=$?
fi
exit $RESULT
Did I miss something when I edit in the MAKEFILE or Kconfig file?
Thanks
Re: How to add .o file in the Linux Kernel
OK, I guess, fakeroot is trying to interpret "CONFIG_TCP_CONG_QUIC=.." as a command - which is wrong.
Instead, what you could do is edit the .config file.
At the end of kernel configuration, "make (x|menu|whatever)config" generates a .config file which is built using all the Kconfig segments.
You can simply edit .config and add CONFIG_TC_CONG_QUIC=m to it. Then reconfigure using "make oldconfig" and then build the kernel using your regular "make-kpkg ..." command.
HTH ;)
Re: How to add .o file in the Linux Kernel
the_unforgiven,
I believe what you wrote is really important, but I am having a hard time understanding or locating the files that you recommended.
When you mean the .config file are you referring to kconfig file?
I ask because I do not know what you mean by here.
Quote:
At the end of kernel configuration, "make (x|menu|whatever)config" generates a .config file which is built using all the Kconfig segments.
When you mention this part:
Quote:
You can simply edit .config and add CONFIG_TCP_CONG_QUIC=m to it. Then reconfigure using "make oldconfig" and then build the kernel using your regular "make-kpkg ..." command.
Are you talking about the kconfig file the lines around here
Code:
config DEFAULT_CUBIC
bool "Cubic" if TCP_CONG_CUBIC=y
config DEFAULT_HTCP
bool "Htcp" if TCP_CONG_HTCP=y
config DEFAULT_HYBLA
bool "Hybla" if TCP_CONG_HYBLA=y
config DEFAULT_VEGAS
bool "Vegas" if TCP_CONG_VEGAS=y
config DEFAULT_VENO
bool "Veno" if TCP_CONG_VENO=y
config DEFAULT_QUIC
bool "Quic" if TCP_CONG_QUIC=m
Thanks
Re: How to add .o file in the Linux Kernel
What I meant was that before compiling the kernel, it needs to be configured for the type of system on which it will run - this is what the various "make config" commands do. For details, check this:
http://lxr.linux.no/linux+*/README#L153
This is true for almost all operating system kernels - linux, *BSD, solaris (I don't know about Windows) - that you need to configure the kernel before compiling it.
During this configuration process, you decide what all features to include in the kernel - some of them can be built into the kernel binary, while others can be compiled as loadable kernel modules (drivers).
At the end of this configuration process, there is a .config file written in the same directory as README/MAINTAINERS files in the kernel sources - it's a simple text file that you can examine using any text editor.
This file is used during the compilation process to different options in various parts of the kernel - CONFIG_TCP_CONG_QUIC being one of them.
"CONFIG_*=m" says that it should be built as a module - whereas, "CONFIG_*=y" means that it should be built into the kernel binary directly.
Most modern linux distros include the configuration with which the kernel was built under /boot/config-<KERNEL_VERSION>. This can be quite helpful as a starting point.
You can just copy this file to .config in your kernel sources and edit it to your liking (for example, add "CONFIG_TCP_CONG_QUIC=m" in the .config file which is copied from /boot/config-<KERNEL_VERSION>).
make-kpkg tries to automate the kernel build process by bundling predefined configuration templates.
I've never used make-kpkg - so, don't know what should be the ideal way. But, ubuntu uses a similar process. In there, there is a directory debian.master/configs/ (or something similar) which stores the configuration templates.
I hope this helps in understanding the basics of kernel build process ;)
Re: How to add .o file in the Linux Kernel
how to add new congstion control like tcp_hybla.c in linux kernel...
step to recompile kernel
step to add new .c file and required changes in kernel...
