eBPF sample programs
====================

This directory contains a test stubs, verifier test-suite and examples
for using eBPF. The examples use libbpf from tools/lib/bpf.

Build dependencies
==================

Compiling requires having installed:
 * clang >= version 3.4.0
 * llvm >= version 3.7.1

Note that LLVM's tool 'llc' must support target 'bpf', list version
and supported targets with command: ``llc --version``

Kernel headers
--------------

There are usually dependencies to header files of the current kernel.
To avoid installing devel kernel headers system wide, as a normal
user, simply call::

 make headers_install

This will creates a local "usr/include" directory in the git/build top
level directory, that the make system automatically pickup first.

Compiling
=========

For building the BPF samples, issue the below command from the kernel
top level directory::

 make samples/bpf/

Do notice the "/" slash after the directory name.

It is also possible to call make from this directory.  This will just
hide the the invocation of make as above with the appended "/".

Manually compiling LLVM with 'bpf' support
------------------------------------------

Since version 3.7.0, LLVM adds a proper LLVM backend target for the
BPF bytecode architecture.

By default llvm will build all non-experimental backends including bpf.
To generate a smaller llc binary one can use::

 -DLLVM_TARGETS_TO_BUILD="BPF"

Quick sniplet for manually compiling LLVM and clang
(build dependencies are cmake and gcc-c++)::

 $ git clone http://llvm.org/git/llvm.git
 $ cd llvm/tools
 $ git clone --depth 1 http://llvm.org/git/clang.git
 $ cd ..; mkdir build; cd build
 $ cmake .. -DLLVM_TARGETS_TO_BUILD="BPF;X86"
 $ make -j $(getconf _NPROCESSORS_ONLN)

It is also possible to point make to the newly compiled 'llc' or
'clang' command via redefining LLC or CLANG on the make command line::

 make samples/bpf/ LLC=~/git/llvm/build/bin/llc CLANG=~/git/llvm/build/bin/clang
thod='get' action='/cgit.cgi/linux/net-next.git/log/'>
<input type='hidden' name='id' value='1a2a14444d32b89b28116daea86f63ced1716668'/><select name='qt'>
<option value='grep'>log msg</option>
<option value='author'>author</option>
<option value='committer'>committer</option>
<option value='range'>range</option>
</select>
<input class='txt' type='search' size='10' name='q' value=''/>
<input type='submit' value='search'/>
</form>
</td></tr></table>
<div class='content'><table class='list nowrap'><tr class='nohover'><th class='left'>Age</th><th class='left'>Commit message (<a href='/cgit.cgi/linux/net-next.git/log/?id=1a2a14444d32b89b28116daea86f63ced1716668&amp;showmsg=1'>Expand</a>)</th><th class='left'>Author</th><th class='left'>Files</th><th class='left'>Lines</th></tr>
<tr><td><span title='2017-02-01 12:10:56 -0500'>2017-02-01</span></td><td><a href='/cgit.cgi/linux/net-next.git/commit/?id=1a2a14444d32b89b28116daea86f63ced1716668'>net: fix ndo_features_check/ndo_fix_features comment ordering</a></td><td>Dimitris Michailidis</td><td>1</td><td><span class='deletions'>-14</span>/<span class='insertions'>+15</span></td></tr>
<tr><td><span title='2017-02-01 11:57:33 -0500'>2017-02-01</span></td><td><a href='/cgit.cgi/linux/net-next.git/commit/?id=fd62d9f5c575f0792f150109f1fd24a0d4b3f854'>net/sched: matchall: Fix configuration race</a></td><td>Yotam Gigi</td><td>1</td><td><span class='deletions'>-82</span>/<span class='insertions'>+45</span></td></tr>
<tr><td><span title='2017-02-01 11:11:41 -0500'>2017-02-01</span></td><td><a href='/cgit.cgi/linux/net-next.git/commit/?id=4993b39ab04b083ff6ee1147e7e7f120feb6bf7f'>be2net: fix initial MAC setting</a></td><td>Ivan Vecera