Only the virtual_bpf.h should point to the installed kernel headers.
Signed-off-by: Brenden Blanco <bblanco@gmail.com>

As is occassionally necessary, we need to update the compat header
files for new kernels. This picks up the bpf.h from 4.10rc1.

Fixes: #877
Signed-off-by: Brenden Blanco <bblanco@gmail.com>

Concretely, it adds two functions to bcc, namely:
`attach_xdp` and `remove_xdp`
which allows to attach an XDP program to a device (given via its name, e.g., en0) (in the future this might change to a specific queue on a device once the kernel offers this interface)
and `remove_xdp` removes a XDP program from a device. Please note that there can currently be only one program attached to the device and attaching another program replaces the previous.

One example is available to test XDP, in networking/xdp which drops all packets an counts for which protocol a packet was dropped (this is taken from the kernel xdp1 example). Please note that you cannot use the network headers defined in <bcc/proto.h> as they cause llvm/clang to generate instructions not available on XDP layer. On XDP layer you do not have an skb yet, so you are operating on the bare packet data.

XDP support is currently limited to only some network adapters, there is the `mlx4` and there is also a patch available for the `e1000` driver.

version checks don't work at all on kernels with backported bpf bits
they also fail when /usr/include/linux/bpf.h doesn't match loaded
kernel.
Fix these issues by embedding bpf.h into libbcc.so and force load it
in clang, so we can remove all version checks and rely on verifier
complaining on unknown function call.
Later patch can make verifier errors less cryptic by converting
'unknown call 12' to strings.

while at it update bpf.h to the latest.
Signed-off-by: Alexei Starovoitov <ast@fb.com>

Pull in bpf.h from upstream, and update helpers accordingly.
Signed-off-by: Brenden Blanco <bblanco@plumgrid.com>

Signed-off-by: Brenden Blanco <bblanco@plumgrid.com>

Signed-off-by: Alexei Starovoitov <ast@plumgrid.com>

* Update compat.h
* Move bpf_clone_redirect to signed int, matching the implementation.
  This allows error codes to be compared to < 0.
Signed-off-by: Brenden Blanco <bblanco@plumgrid.com>

Signed-off-by: Yonghong Song <yhs@plumgrid.com>

* Add RPM and DEB packaging targets (using CPack from CMake) to build
  binary packages for Fedora and Ubuntu targets.
* Add Docker build scripts for each of the above that run the build in
  the right environment (assuming docker is available).
 - In Ubuntu, build against the LLVM 3.7 nightly snapshots
 - In Fedora, build against LLVM 3.7 from git (takes longer)
* Depending on packages installed on the build machine, it may be
  possible to cross-package for other targets without invoking Docker.
* Re-introduce src/cc/compat directory to keep the build stable for the
  time being. Similarly, it was necessary to #define some ugly constants
  that should eventually show up in libc.
* Add a few simple version checks to allow a partially working (really
  tracing only) libbcc in 4.1 kernels.

TODO (followup commit): Re-work the READMEs
Signed-off-by: Brenden Blanco <bblanco@plumgrid.com>