Stepping down as I haven't had a chance to look into the powerpc
BPF JIT compilers for a while.
Signed-off-by: Sandipan Das <sandipan@linux.ibm.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20210827111905.396145-1-sandipan@linux.ibm.com

This lock is not released if the program
return at the patched branch.
Signed-off-by: Chengfeng Ye <cyeaa@connect.ust.hk>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20210827074140.118671-1-cyeaa@connect.ust.hk

While at it, also improve help output when CPU number is greater than
possible.

Fixes: e531a220 ("samples: bpf: Convert xdp_redirect_cpu to XDP samples helper")
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20210826120910.454081-1-memxor@gmail.com

This patch adds similar retry logic to more places where read() is used, to
reduce flakyness in slow CI environment.
Signed-off-by: Yucong Sun <fallentree@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20210825184745.2680830-1-fallentree@fb.com

This commit fixes linker errors along the lines of:

    s390-linux-ld: task_iter.c:(.init.text+0xa4): undefined reference to `btf_task_struct_ids'`

Fix by defining btf_task_struct_ids unconditionally in kernel/bpf/btf.c
since there exists code that unconditionally uses btf_task_struct_ids.
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Daniel Xu <dxu@dxuuu.xyz>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/05d94748d9f4b3eecedc4fddd6875418a396e23c.1629942444.git.dxu@dxuuu.xyz

Martin KaFai says:

====================

This set allows the bpf-tcp-cc to call bpf_setsockopt.  One use
case is to allow a bpf-tcp-cc switching to another cc during init().
For example, when the tcp flow is not ecn ready, the bpf_dctcp
can switch to another cc by calling setsockopt(TCP_CONGESTION).

bpf_getsockopt() is also added to have a symmetrical API, so
less usage surprise.

v2:
- Not allow switching to kernel's tcp_cdg because it is the only
  kernel tcp-cc that stores a pointer to icsk_ca_priv.
  Please see the commit log in patch 1 for details.
  Test is added in patch 4 to check switching to tcp_cdg.
- Refactor the logic finding the offset of a func ptr
  in the "struct tcp_congestion_ops" to prog_ops_moff()
  in patch 1.
- bpf_setsockopt() has been disabled in release() since v1 (please
  see commit log in patch 1 for reason).  bpf_getsockopt() is
  also disabled together in release() in v2 to avoid usage surprise
  because both of them are usually expected to be available together.
  bpf-tcp-cc can already use PTR_TO_BTF_ID to read from tcp_sock.
====================
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

This patch makes the bpf_dctcp test to fallback to cubic by
using setsockopt(TCP_CONGESTION) when the tcp flow is not
ecn ready.

It also checks setsockopt() is not available to release().

The settimeo() from the network_helpers.h is used, so the local
one is removed.
Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20210824173026.3979130-1-kafai@fb.com

The next test requires to setsockopt(TCP_CONGESTION) before
connect(), so a new arg is needed for the connect_to_fd() to specify
the cc's name.

This patch adds a new "struct network_helper_opts" for the future
option needs.  It starts with the "cc" and "timeout_ms" option.
A new helper connect_to_fd_opts() is added to take the new
"const struct network_helper_opts *opts" as an arg.
Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20210824173019.3977910-1-kafai@fb.com

Add sk_state define to bpf_tcp_helpers.h.  Rename the existing
global variable "sk_state" in the kfunc_call test to "sk_state_res".
Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20210824173013.3977316-1-kafai@fb.com

This patch allows the bpf-tcp-cc to call bpf_setsockopt.  One use
case is to allow a bpf-tcp-cc switching to another cc during init().
For example, when the tcp flow is not ecn ready, the bpf_dctcp
can switch to another cc by calling setsockopt(TCP_CONGESTION).

During setsockopt(TCP_CONGESTION), the new tcp-cc's init() will be
called and this could cause a recursion but it is stopped by the
current trampoline's logic (in the prog->active counter).

While retiring a bpf-tcp-cc (e.g. in tcp_v[46]_destroy_sock()),
the tcp stack calls bpf-tcp-cc's release().  To avoid the retiring
bpf-tcp-cc making further changes to the sk, bpf_setsockopt is not
available to the bpf-tcp-cc's release().  This will avoid release()
making setsockopt() call that will potentially allocate new resources.

Although the bpf-tcp-cc already has a more powerful way to read tcp_sock
from the PTR_TO_BTF_ID, it is usually expected that bpf_getsockopt and
bpf_setsockopt are available together.  Thus, bpf_getsockopt() is also
added to all tcp_congestion_ops except release().

When the old bpf-tcp-cc is calling setsockopt(TCP_CONGESTION)
to switch to a new cc, the old bpf-tcp-cc will be released by
bpf_struct_ops_put().  Thus, this patch also puts the bpf_struct_ops_map
after a rcu grace period because the trampoline's image cannot be freed
while the old bpf-tcp-cc is still running.

bpf-tcp-cc can only access icsk_ca_priv as SCALAR.  All kernel's
tcp-cc is also accessing the icsk_ca_priv as SCALAR.   The size
of icsk_ca_priv has already been raised a few times to avoid
extra kmalloc and memory referencing.  The only exception is the
kernel's tcp_cdg.c that stores a kmalloc()-ed pointer in icsk_ca_priv.
To avoid the old bpf-tcp-cc accidentally overriding this tcp_cdg's pointer
value stored in icsk_ca_priv after switching and without over-complicating
the bpf's verifier for this one exception in tcp_cdg, this patch does not
allow switching to tcp_cdg.  If there is a need, bpf_tcp_cdg can be
implemented and then use the bpf_sk_storage as the extended storage.

bpf_sk_setsockopt proto has only been recently added and used
in bpf-sockopt and bpf-iter-tcp, so impose the tcp_cdg limitation in the
same proto instead of adding a new proto specifically for bpf-tcp-cc.
Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20210824173007.3976921-1-kafai@fb.com

Magnus Karlsson says:

====================

This patch set mainly contains various simplifications to the xsk
selftests. The only exception is the introduction of packet streams
that describes what the Tx process should send and what the Rx process
should receive. If it receives anything else, the test fails. This
mechanism can be used to produce tests were all packets are not
received by the Rx thread or modified in some way. An example of this
is if an XDP program does XDP_PASS on some of the packets.

This patch set will be followed by another patch set that implements a
new structure that will facilitate adding new tests. A couple of new
tests will also be included in that patch set.

v2 -> v3:

* Reworked patch 12 so that it now has functions for creating and
  destroying ifobjects. Simplifies the code. [Maciej]
* The packet stream now allocates the supplied buffer array length,
  instead of the default one. [Maciej]
* pkt_stream_get_pkt() now returns NULL when indexing a non-existing
  packet. [Maciej]
* pkt_validate() is now is_pkt_valid(). [Maciej]
* Slowed down packet sending speed even more in patch 11 so that slow
  systems do not silenty drop packets in skb mode.

v1 -> v2:

* Dropped the patch with per process limit changes as it is not needed
  [Yonghong]
* Improved the commit message of patch 1 [Yonghong]
* Fixed a spelling error in patch 9

Thanks: Magnus
====================
Acked-by: Maciej Fijalkowski <maciej.fijalkowski@intel.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

Preface all options with opt_ and make them booleans.
Signed-off-by: Magnus Karlsson <magnus.karlsson@intel.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20210825093722.10219-17-magnus.karlsson@gmail.com

Make enums lower case as that is the standard. Also drop the
unnecessary TEST_MODE_UNCONFIGURED mode.
Signed-off-by: Magnus Karlsson <magnus.karlsson@intel.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20210825093722.10219-16-magnus.karlsson@gmail.com

Generate packets from a specification instead of something hard
coded. The idea is that a test generates one or more packet
specifications and provides it/them to both Tx and Rx. The Tx thread
will generate from this specification and Rx will validate that it
receives what is in the specification. The specification can be the
same on both ends, meaning that everything that was sent should be
received, or different which means that Rx will only receive part of
the sent packets.

Currently, the packet specification is the same for both Rx and Tx and
the same for each test. This will change in later work as features
and tests are added.

The data path functions are also renamed to better reflect what
actions they are performing after introducing this feature.
Signed-off-by: Magnus Karlsson <magnus.karlsson@intel.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20210825093722.10219-15-magnus.karlsson@gmail.com

Generate the packet directly in the umem instead of in a temporary
buffer that is copied out. Simplifies the code and improves
performance.
Signed-off-by: Magnus Karlsson <magnus.karlsson@intel.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20210825093722.10219-14-magnus.karlsson@gmail.com

Simpify the cleanup of ifobjects right before the program exits by
introducing functions for creating and destroying these objects.
Signed-off-by: Magnus Karlsson <magnus.karlsson@intel.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20210825093722.10219-13-magnus.karlsson@gmail.com

Decrease sending speed to avoid potentially overflowing some buffers
in the skb case that leads to dropped packets we cannot control (and
thus the tests may generate false negatives). Decrease batch size and
introduce a usleep in the transmit thread to not overflow the
receiver.
Signed-off-by: Magnus Karlsson <magnus.karlsson@intel.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20210825093722.10219-12-magnus.karlsson@gmail.com

Validate the tx stats on the Tx thread instead of the Rx
thread. Depending on your settings, you might not be allowed to query
the statistics of a socket you do not own, so better to do this on the
correct thread to start with.
Signed-off-by: Magnus Karlsson <magnus.karlsson@intel.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20210825093722.10219-11-magnus.karlsson@gmail.com

Simplify packet validation in the xsk selftests by performing it at
once for every packet. The current code performed this per batch and
did this on copied packet data. Make it simpler and faster by
validating it at once and on the umem packet data thus skipping the
copy and the memory allocation for the temprary buffer.

The optional packet dump feature is also simplified in the same
manner. Memory allocation and copying is removed and the dump is
performed directly on the umem data.
Signed-off-by: Magnus Karlsson <magnus.karlsson@intel.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20210825093722.10219-10-magnus.karlsson@gmail.com

Rename worker_* functions that are not thread entry points to
something else. This was confusing. Now only thread entry points are
worker_something.
Signed-off-by: Magnus Karlsson <magnus.karlsson@intel.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20210825093722.10219-9-magnus.karlsson@gmail.com

Disassociate the number of packets sent with the number of buffers in
the umem. This so we can loop over the umem to test more things. Set
the size of the umem to be a multiple of 2M. A requirement for huge
pages that are needed in unaligned mode.
Signed-off-by: Magnus Karlsson <magnus.karlsson@intel.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20210825093722.10219-8-magnus.karlsson@gmail.com

Get rid of the end-of-test packet and just count the number of packets
received and quit when the expected number as been
received. Simplifies the code.
Signed-off-by: Magnus Karlsson <magnus.karlsson@intel.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20210825093722.10219-7-magnus.karlsson@gmail.com

Simplify the retry code and make it more efficient by waiting first,
instead of trying immediately which always fails due to the
asynchronous nature of xsk socket close. Also decrease the wait time
to significantly lower the run-time of the test suite.
Signed-off-by: Magnus Karlsson <magnus.karlsson@intel.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20210825093722.10219-6-magnus.karlsson@gmail.com

Return the correct error codes so they can be printed correctly.
Signed-off-by: Magnus Karlsson <magnus.karlsson@intel.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20210825093722.10219-5-magnus.karlsson@gmail.com

Remove unused variables and typedefs. The *_npkts variables are
incremented but never used.
Signed-off-by: Magnus Karlsson <magnus.karlsson@intel.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20210825093722.10219-4-magnus.karlsson@gmail.com

Remove the number of tx packet option as this should be decided by the
test itself. Also change the number of packets to be sent to 4096
speeding up the execution.
Signed-off-by: Magnus Karlsson <magnus.karlsson@intel.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20210825093722.10219-3-magnus.karlsson@gmail.com

Remove color mode since it does not add any value and having less code
means less maintenance which is a good thing.
Signed-off-by: Magnus Karlsson <magnus.karlsson@intel.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20210825093722.10219-2-magnus.karlsson@gmail.com

Daniel Xu says:

====================

The motivation behind this helper is to access userspace pt_regs in a
kprobe handler.

uprobe's ctx is the userspace pt_regs. kprobe's ctx is the kernelspace
pt_regs. bpf_task_pt_regs() allows accessing userspace pt_regs in a
kprobe handler. The final case (kernelspace pt_regs in uprobe) is
pretty rare (usermode helper) so I think that can be solved later if
necessary.

More concretely, this helper is useful in doing BPF-based DWARF stack
unwinding. Currently the kernel can only do framepointer based stack
unwinds for userspace code. This is because the DWARF state machines are
too fragile to be computed in kernelspace [0]. The idea behind
DWARF-based stack unwinds w/ BPF is to copy a chunk of the userspace
stack (while in prog context) and send it up to userspace for unwinding
(probably with libunwind) [1]. This would effectively enable profiling
applications with -fomit-frame-pointer using kprobes and uprobes.

[0]: https://lkml.org/lkml/2012/2/10/356
[1]: https://github.com/danobi/bpf-dwarf-walk

Changes from v1:
- Conwolidate BTF_ID decls for task_struct
- Enable bpf_get_current_task_btf() for all prog types
- Enable bpf_task_pt_regs() for all prog types
- Use ASSERT_* macros instead of CHECK
====================
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

This test retrieves the uprobe's pt_regs in two different ways and
compares the contents in an arch-agnostic way.
Signed-off-by: Daniel Xu <dxu@dxuuu.xyz>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/5581eb8800f6625ec8813fe21e9dce1fbdef4937.1629772842.git.dxu@dxuuu.xyz

The motivation behind this helper is to access userspace pt_regs in a
kprobe handler.

uprobe's ctx is the userspace pt_regs. kprobe's ctx is the kernelspace
pt_regs. bpf_task_pt_regs() allows accessing userspace pt_regs in a
kprobe handler. The final case (kernelspace pt_regs in uprobe) is
pretty rare (usermode helper) so I think that can be solved later if
necessary.

More concretely, this helper is useful in doing BPF-based DWARF stack
unwinding. Currently the kernel can only do framepointer based stack
unwinds for userspace code. This is because the DWARF state machines are
too fragile to be computed in kernelspace [0]. The idea behind
DWARF-based stack unwinds w/ BPF is to copy a chunk of the userspace
stack (while in prog context) and send it up to userspace for unwinding
(probably with libunwind) [1]. This would effectively enable profiling
applications with -fomit-frame-pointer using kprobes and uprobes.

[0]: https://lkml.org/lkml/2012/2/10/356
[1]: https://github.com/danobi/bpf-dwarf-walkSigned-off-by: Daniel Xu <dxu@dxuuu.xyz>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/e2718ced2d51ef4268590ab8562962438ab82815.1629772842.git.dxu@dxuuu.xyz

bpf_get_current_task() is already supported so it's natural to also
include the _btf() variant for btf-powered helpers.

This is required for non-tracing progs to use bpf_task_pt_regs() in the
next commit.
Signed-off-by: Daniel Xu <dxu@dxuuu.xyz>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/f99870ed5f834c9803d73b3476f8272b1bb987c0.1629772842.git.dxu@dxuuu.xyz

No need to have it defined 5 times. Once is enough.
Signed-off-by: Daniel Xu <dxu@dxuuu.xyz>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/6dcefa5bed26fe1226f26683f36819bb53ec19a2.1629772842.git.dxu@dxuuu.xyz

Same as BTF_ID_LIST_SINGLE macro except defines a global ID.
Signed-off-by: Daniel Xu <dxu@dxuuu.xyz>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/a867a97517df42fd3953eeb5454402b57e74538f.1629772842.git.dxu@dxuuu.xyz

Kumar Kartikeya says:

====================

This set revamps XDP samples related to redirection to show better output and
implement missing features consolidating all their differences and giving them a
consistent look and feel, by implementing common features and command line
options.  Some of the TODO items like reporting redirect error numbers
(ENETDOWN, EINVAL, ENOSPC, etc.) have also been implemented.

Some of the features are:
* Received packet statistics
* xdp_redirect/xdp_redirect_map tracepoint statistics
* xdp_redirect_err/xdp_redirect_map_err tracepoint statistics (with support for
  showing exact errno)
* xdp_cpumap_enqueue/xdp_cpumap_kthread tracepoint statistics
* xdp_devmap_xmit tracepoint statistics
* xdp_exception tracepoint statistics
* Per ifindex pair devmap_xmit stats shown dynamically (for xdp_monitor) to
  decompose the total.
* Use of BPF skeleton and BPF static linking to share BPF programs.
* Use of vmlinux.h and tp_btf for raw_tracepoint support.
* Removal of redundant -N/--native-mode option (enforced by default now)
* ... and massive cleanups all over the place.

All tracepoints also use raw_tp now, and tracepoints like xdp_redirect
are only enabled when requested explicitly to capture successful redirection
statistics.

The set of programs converted as part of this series are:
 * xdp_redirect_cpu
 * xdp_redirect_map_multi
 * xdp_redirect_map
 * xdp_redirect
 * xdp_monitor

 Explanation of the output:

There is now a concise output mode by default that shows primarily four fields:
  rx/s        Number of packets received per second
  redir/s     Number of packets successfully redirected per second
  err,drop/s  Aggregated count of errors per second (including dropped packets)
  xmit/s      Number of packets transmitted on the output device per second

Some examples:
 ; sudo ./xdp_redirect_map veth0 veth1 -s
Redirecting from veth0 (ifindex 15; driver veth) to veth1 (ifindex 14; driver veth)
veth0->veth1                    0 rx/s                  0 redir/s		0 err,drop/s               0 xmit/s
veth0->veth1            9,998,660 rx/s          9,998,658 redir/s		0 err,drop/s       9,998,654 xmit/s
...

There is also a verbose mode, that can also be enabled by default using -v (--verbose).
The output mode can be switched dynamically at runtime using Ctrl + \ (SIGQUIT).

To make the concise output more useful, the errors that occur are expanded inline
(as if verbose mode was enabled) to let the user pin down the source of the
problem without having to clutter output (or possibly miss it) or always use verbose mode.

For instance, let's consider a case where the output device link state is set to
down while redirection is happening:

[...]
veth0->veth1           24,503,376 rx/s                  0 err,drop/s      24,503,372 xmit/s
veth0->veth1           25,044,775 rx/s                  0 err,drop/s      25,044,783 xmit/s
veth0->veth1           25,263,046 rx/s                  4 err,drop/s      25,263,028 xmit/s
  redirect_err                  4 error/s
    ENETDOWN                    4 error/s
[...]

The same holds for xdp_exception actions.

An example of how a complete xdp_redirect_map session would look:

 ; sudo ./xdp_redirect_map veth0 veth1
Redirecting from veth0 (ifindex 5; driver veth) to veth1 (ifindex 4; driver veth)
veth0->veth1            7,411,506 rx/s                  0 err,drop/s    7,411,470 xmit/s
veth0->veth1            8,931,770 rx/s                  0 err,drop/s    8,931,771 xmit/s
^\
veth0->veth1            8,787,295 rx/s                  0 err,drop/s    8,787,325 xmit/s
  receive total         8,787,295 pkt/s                 0 drop/s                0 error/s
    cpu:7               8,787,295 pkt/s                 0 drop/s                0 error/s
  redirect_err                  0 error/s
  xdp_exception                 0 hit/s
  xmit veth0->veth1     8,787,325 xmit/s                0 drop/s                0 drv_err/s          2.00 bulk-avg
     cpu:7              8,787,325 xmit/s                0 drop/s                0 drv_err/s          2.00 bulk-avg

veth0->veth1            8,842,610 rx/s                  0 err,drop/s    8,842,606 xmit/s
  receive total         8,842,610 pkt/s                 0 drop/s                0 error/s
    cpu:7               8,842,610 pkt/s                 0 drop/s                0 error/s
  redirect_err                  0 error/s
  xdp_exception                 0 hit/s
  xmit veth0->veth1     8,842,606 xmit/s                0 drop/s                0 drv_err/s          2.00 bulk-avg
     cpu:7              8,842,606 xmit/s                0 drop/s                0 drv_err/s          2.00 bulk-avg

^C
  Packets received    : 33,973,181
  Average packets/s   : 4,246,648
  Packets transmitted : 33,973,172
  Average transmit/s  : 4,246,647

The xdp_redirect tracepoint (for success stats) needs to be enabled explicitly
using --stats/-s. Documentation for entire output and options is provided when
user specifies --help/-h with a sample.

Changelog:
----------
v3 -> v4:
v3: https://lore.kernel.org/bpf/20210728165552.435050-1-memxor@gmail.com

 * Address all feedback from Daniel
  * Use READ_ONCE/WRITE_ONCE from linux/compiler.h (cannot directly include
    due to conflicts with vmlinux.h)
  * Fix MAX_CPUS hardcoding by switching to mmapable array maps, that are
    resized based on the value of libbpf_num_possible_cpus
  * s/ELEMENTS_OF/ARRAY_SIZE/g
  * Use tools/include/linux/hashtable.h
  * Coding style fixes
  * Remove hyperlinks for tracepoints
  * Split into smaller reviewable changes
 * Restore support for specifying custom xdp_redirect_cpu cpumap prog with some
   enhancements, including built-in programs for common actions (pass, drop,
   redirect). By default, cpumap prog is now disabled.
 * Misc bug fixes all over the place

  The printing stuff is a lot more basic without hyperlink support, hence it
  has not been exported into a more general facility.

v2 -> v3
v2: https://lore.kernel.org/bpf/20210721212833.701342-1-memxor@gmail.com

 * Address all feedback from Andrii
  * Replace usage of libbpf hashmap (internal API) with custom one
  * Rename ATOMIC_* macros to NO_TEAR_* to better reflect their use
  * Use size_t as a portable word sized data type
  * Set libbpf_set_strict_mode
  * Invert conditions in BPF programs to exit early and reduce nesting
  * Use canonical SEC("xdp") naming for all XDP BPF progams
 * Add missing help description for cpumap enqueue and kthread tracepoints
 * Move private struct declarations from xdp_sample_user.h to .c file
 * Improve help output for cpumap enqueue and cpumap kthread tracepoints
 * Fix a bug where keys array for BPF_MAP_LOOKUP_BATCH is overallocated
 * Fix some conditions for printing stats (earlier only checked pps, now pps,
   drop, err and print if any is greater than zero)
 * Fix alloc_stats_record to properly return and cleanup allocated memory on
   allocation failure instead of calling exit(3)
 * Bump bpf_map_lookup_batch count to 32 to reduce lookup time with multiple
   devices in map
 * Fix a bug where devmap_xmit_multi stats are not printed when previous record
   is missing (i.e. when the first time stats are printed), by simply using a
   dummy record that is zeroed out
 * Also print per-CPU counts for devmap_xmit_multi which we collect already
 * Change mac_map to be BPF_MAP_TYPE_HASH instead of array to prevent resizing
   to a large size when max_ifindex is high, in xdp_redirect_map_multi
 * Fix instance of strerror(errno) in sample_install_xdp to use saved errno
 * Provide a usage function from samples helper
 * Provide a fix where incorrect stats are shown for parallel sessions of
   xdp_redirect_* samples by introducing matching support for input device(s),
   output device(s) and cpumap map id for enqueue and kthread stats.
   Only xdp_monitor doesn't filter stats, all others do.

RFC (v1) -> v2
RFC (v1): https://lore.kernel.org/bpf/20210528235250.2635167-1-memxor@gmail.com

 * Address all feedback from Andrii
   * Use BPF static linking
   * Use vmlinux.h
   * Use BPF_PROG macro
   * Use global variables instead of maps
 * Use of tp_btf for raw_tracepoint progs
 * Switch to timerfd for polling
 * Use libbpf hashmap for maintaing device sets for per ifindex pair
   devmap_xmit stats
 * Fix Makefile to specify object dependencies properly
 * Use in-tree bpftool
 * ... misc fixes and cleanups all over the place
====================
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

Use the libbpf skeleton facility and other utilities provided by XDP
samples helper. Also adapt to change of type of mac address map, so that
no resizing is required.

Add a new flag for sample mask that skips priting the
from_device->to_device heading for each line, as xdp_redirect_map_multi
may have two devices but the flow of data may be bidirectional, so the
output would be confusing.
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20210821002010.845777-23-memxor@gmail.com

One of the notable changes is using a BPF_MAP_TYPE_HASH instead of array
map to store mac addresses of devices, as the resizing behavior was
based on max_ifindex, which unecessarily maximized the capacity of map
beyond what was needed.
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20210821002010.845777-22-memxor@gmail.com

Use the libbpf skeleton facility and other utilities provided by XDP
samples helper.

Since get_mac_addr is already provided by XDP samples helper, we drop
it. Also convert to XDP samples helper similar to prior samples to
minimize duplication of code.
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20210821002010.845777-21-memxor@gmail.com

Also update it to use consistent SEC("xdp") and SEC("xdp_devmap")
naming, and use global variable instead of BPF map for copying the mac
address.
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20210821002010.845777-20-memxor@gmail.com

Use the libbpf skeleton facility and other utilities provided by XDP
samples helper.

Similar to xdp_monitor, xdp_redirect_cpu was quite featureful except a
few minor omissions (e.g. redirect errno reporting). All of these have
been moved to XDP samples helper, hence drop the unneeded code and
convert to usage of helpers provided by it.

One of the important changes here is dropping of mprog-disable option,
as we make that the default. Also, we support built-in programs for some
common actions on the packet when it reaches kthread (pass, drop,
redirect to device). If the user still needs to install a custom
program, they can still supply a BPF object, however the program should
be suitably tagged with SEC("xdp_cpumap") annotation so that the
expected attach type is correct when updating our cpumap map element.
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20210821002010.845777-19-memxor@gmail.com

Similar to xdp_monitor_kern, a lot of these BPF programs have been
reimplemented properly consolidating missing features from other XDP
samples. Hence, drop the unneeded code and rename to .bpf.c suffix.
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20210821002010.845777-18-memxor@gmail.com