Zero-length and one-element arrays are deprecated, see:
Documentation/process/deprecated.rst

Flexible-array members should be used instead.

Generated by: scripts/coccinelle/misc/flexible_array.cocci

Fixes: c1ff181f

 ("selftests/bpf: Extend kfunc selftests")
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: kernel test robot <lkp@intel.com>
Signed-off-by: Julia Lawall <julia.lawall@inria.fr>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Cc: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/bpf/alpine.DEB.2.22.394.2201221206320.12220@hadrien

Lorenzo Bianconi says:

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

This series introduces XDP frags support. The mvneta driver is
the first to support these new "non-linear" xdp_{buff,frame}. Reviewers
please focus on how these new types of xdp_{buff,frame} packets
traverse the different layers and the layout design. It is on purpose
that BPF-helpers are kept simple, as we don't want to expose the
internal layout to allow later changes.

The main idea for the new XDP frags layout is to reuse the same
structure used for non-linear SKB. This rely on the "skb_shared_info"
struct at the end of the first buffer to link together subsequent
buffers. Keeping the layout compatible with SKBs is also done to ease
and speedup creating a SKB from an xdp_{buff,frame}.
Converting xdp_frame to SKB and deliver it to the network stack is shown
in patch 05/18 (e.g. cpumaps).

A frags bit (XDP_FLAGS_HAS_FRAGS) has been introduced in the flags
field of xdp_{buff,frame} structure to notify the bpf/network layer if
this is a non-linear xdp frame (XDP_FLAGS_HAS_FRAGS set) or not
(XDP_FLAGS_HAS_FRAGS not set).
The frags bit will be set by a xdp frags capable driver only
for non-linear frames maintaining the capability to receive linear frames
without any extra cost since the skb_shared_info structure at the end
of the first buffer will be initialized only if XDP_FLAGS_HAS_FRAGS bit
is set. Moreover the flags field in xdp_{buff,frame} will be reused even for
xdp rx csum offloading in future series.

Typical use cases for this series are:
- Jumbo-frames
- Packet header split (please see Google’s use-case @ NetDevConf 0x14, [0])
- TSO/GRO for XDP_REDIRECT

The three following ebpf helpers (and related selftests) has been introduced:
- bpf_xdp_load_bytes:
  This helper is provided as an easy way to load data from a xdp buffer. It
  can be used to load len bytes from offset from the frame associated to
  xdp_md, into the buffer pointed by buf.
- bpf_xdp_store_bytes:
  Store len bytes from buffer buf into the frame associated to xdp_md, at
  offset.
- bpf_xdp_get_buff_len:
  Return the total frame size (linear + paged parts)

bpf_xdp_adjust_tail and bpf_xdp_copy helpers have been modified to take into
account non-linear xdp frames.
Moreover, similar to skb_header_pointer, we introduced bpf_xdp_pointer utility
routine to return a pointer to a given position in the xdp_buff if the
requested area (offset + len) is contained in a contiguous memory area
otherwise it must be copied in a bounce buffer provided by the caller running
bpf_xdp_copy_buf().

BPF_F_XDP_HAS_FRAGS flag has been introduced to notify the kernel the
eBPF program fully support xdp frags.
SEC("xdp.frags"), SEC_DEF("xdp.frags/devmap") and SEC_DEF("xdp.frags/cpumap")
have been introduced to declare xdp frags support.
The NIC driver is expected to reject an eBPF program if it is running in
XDP frags mode and the program does not support XDP frags.
In the same way it is not possible to mix XDP frags and XDP legacy
programs in a CPUMAP/DEVMAP or tailcall a XDP frags/legacy program from
a legacy/frags one.

More info about the main idea behind this approach can be found here [1][2].

Changes since v22:
- remove leftover CHECK macro usage
- reintroduce SEC_XDP_FRAGS flag in sec_def_flags
- rename xdp multi_frags in xdp frags
- do not report xdp_frags support in fdinfo

Changes since v21:
- rename *_mb in *_frags: e.g:
  s/xdp_buff_is_mb/xdp_buff_has_frags
- rely on ASSERT_* and not on CHECK in
  bpf_xdp_load_bytes/bpf_xdp_store_bytes self-tests
- change new multi.frags SEC definitions to use the following schema:
  prog_type.prog_flags/attach_place
- get rid of unnecessary properties in new multi.frags SEC definitions
- rebase on top of bpf-next

Changes since v20:
- rebase to current bpf-next

Changes since v19:
- do not run deprecated bpf_prog_load()
- rely on skb_frag_size_add/skb_frag_size_sub in
  bpf_xdp_mb_increase_tail/bpf_xdp_mb_shrink_tail
- rely on sinfo->nr_frags in bpf_xdp_mb_shrink_tail to check if the frame has
  been shrunk to a single-buffer one
- allow XDP_REDIRECT of a xdp-mb frame into a CPUMAP

Changes since v18:
- fix bpf_xdp_copy_buf utility routine when we want to load/store data
  contained in frag<n>
- add a selftest for bpf_xdp_load_bytes/bpf_xdp_store_bytes when the caller
  accesses data contained in frag<n> and frag<n+1>

Changes since v17:
- rework bpf_xdp_copy to squash base and frag management
- remove unused variable in bpf_xdp_mb_shrink_tail()
- move bpf_xdp_copy_buf() out of bpf_xdp_pointer()
- add sanity check for len in bpf_xdp_pointer()
- remove EXPORT_SYMBOL for __xdp_return()
- introduce frag_size field in xdp_rxq_info to let the driver specify max value
  for xdp fragments. frag_size set to 0 means the tail increase of last the
  fragment is not supported.

Changes since v16:
- do not allow tailcalling a xdp multi-buffer/legacy program from a
  legacy/multi-buff one.
- do not allow mixing xdp multi-buffer and xdp legacy programs in a
  CPUMAP/DEVMAP
- add selftests for CPUMAP/DEVMAP xdp mb compatibility
- disable XDP_REDIRECT for xdp multi-buff for the moment
- set max offset value to 0xffff in bpf_xdp_pointer
- use ARG_PTR_TO_UNINIT_MEM and ARG_CONST_SIZE for arg3_type and arg4_type
  of bpf_xdp_store_bytes/bpf_xdp_load_bytes

Changes since v15:
- let the verifier check buf is not NULL in
  bpf_xdp_load_bytes/bpf_xdp_store_bytes helpers
- return an error if offset + length is over frame boundaries in
  bpf_xdp_pointer routine
- introduce BPF_F_XDP_MB flag for bpf_attr to notify the kernel the eBPF
  program fully supports xdp multi-buffer.
- reject a non XDP multi-buffer program if the driver is running in
  XDP multi-buffer mode.

Changes since v14:
- intrudce bpf_xdp_pointer utility routine and
  bpf_xdp_load_bytes/bpf_xdp_store_bytes helpers
- drop bpf_xdp_adjust_data helper
- drop xdp_frags_truesize in skb_shared_info
- explode bpf_xdp_mb_adjust_tail in bpf_xdp_mb_increase_tail and
  bpf_xdp_mb_shrink_tail

Changes since v13:
- use u32 for xdp_buff/xdp_frame flags field
- rename xdp_frags_tsize in xdp_frags_truesize
- fixed comments

Changes since v12:
- fix bpf_xdp_adjust_data helper for single-buffer use case
- return -EFAULT in bpf_xdp_adjust_{head,tail} in case the data pointers are not
  properly reset
- collect ACKs from John

Changes since v11:
- add missing static to bpf_xdp_get_buff_len_proto structure
- fix bpf_xdp_adjust_data helper when offset is smaller than linear area length.

Changes since v10:
- move xdp->data to the requested payload offset instead of to the beginning of
  the fragment in bpf_xdp_adjust_data()

Changes since v9:
- introduce bpf_xdp_adjust_data helper and related selftest
- add xdp_frags_size and xdp_frags_tsize fields in skb_shared_info
- introduce xdp_update_skb_shared_info utility routine in ordere to not reset
  frags array in skb_shared_info converting from a xdp_buff/xdp_frame to a skb
- simplify bpf_xdp_copy routine

Changes since v8:
- add proper dma unmapping if XDP_TX fails on mvneta for a xdp multi-buff
- switch back to skb_shared_info implementation from previous xdp_shared_info
  one
- avoid using a bietfield in xdp_buff/xdp_frame since it introduces performance
  regressions. Tested now on 10G NIC (ixgbe) to verify there are no performance
  penalties for regular codebase
- add bpf_xdp_get_buff_len helper and remove frame_length field in xdp ctx
- add data_len field in skb_shared_info struct
- introduce XDP_FLAGS_FRAGS_PF_MEMALLOC flag

Changes since v7:
- rebase on top of bpf-next
- fix sparse warnings
- improve comments for frame_length in include/net/xdp.h

Changes since v6:
- the main difference respect to previous versions is the new approach proposed
  by Eelco to pass full length of the packet to eBPF layer in XDP context
- reintroduce multi-buff support to eBPF kself-tests
- reintroduce multi-buff support to bpf_xdp_adjust_tail helper
- introduce multi-buffer support to bpf_xdp_copy helper
- rebase on top of bpf-next

Changes since v5:
- rebase on top of bpf-next
- initialize mb bit in xdp_init_buff() and drop per-driver initialization
- drop xdp->mb initialization in xdp_convert_zc_to_xdp_frame()
- postpone introduction of frame_length field in XDP ctx to another series
- minor changes

Changes since v4:
- rebase ontop of bpf-next
- introduce xdp_shared_info to build xdp multi-buff instead of using the
  skb_shared_info struct
- introduce frame_length in xdp ctx
- drop previous bpf helpers
- fix bpf_xdp_adjust_tail for xdp multi-buff
- introduce xdp multi-buff self-tests for bpf_xdp_adjust_tail
- fix xdp_return_frame_bulk for xdp multi-buff

Changes since v3:
- rebase ontop of bpf-next
- add patch 10/13 to copy back paged data from a xdp multi-buff frame to
  userspace buffer for xdp multi-buff selftests

Changes since v2:
- add throughput measurements
- drop bpf_xdp_adjust_mb_header bpf helper
- introduce selftest for xdp multibuffer
- addressed comments on bpf_xdp_get_frags_count
- introduce xdp multi-buff support to cpumaps

Changes since v1:
- Fix use-after-free in xdp_return_{buff/frame}
- Introduce bpf helpers
- Introduce xdp_mb sample program
- access skb_shared_info->nr_frags only on the last fragment

Changes since RFC:
- squash multi-buffer bit initialization in a single patch
- add mvneta non-linear XDP buff support for tx side

[0] https://netdevconf.info/0x14/session.html?talk-the-path-to-tcp-4k-mtu-and-rx-zerocopy
[1] https://github.com/xdp-project/xdp-project/blob/master/areas/core/xdp-multi-buffer01-design.org
[2] https://netdevconf.info/0x14/session.html?tutorial-add-XDP-support-to-a-NIC-driver (XDPmulti-buffers section)

Eelco Chaudron (3):
  bpf: add frags support to the bpf_xdp_adjust_tail() API
  bpf: add frags support to xdp copy helpers
  bpf: selftests: update xdp_adjust_tail selftest to include xdp frags

Lorenzo Bianconi (19):
  net: skbuff: add size metadata to skb_shared_info for xdp
  xdp: introduce flags field in xdp_buff/xdp_frame
  net: mvneta: update frags bit before passing the xdp buffer to eBPF
    layer
  net: mvneta: simplify mvneta_swbm_add_rx_fragment management
  net: xdp: add xdp_update_skb_shared_info utility routine
  net: marvell: rely on xdp_update_skb_shared_info utility routine
  xdp: add frags support to xdp_return_{buff/frame}
  net: mvneta: add frags support to XDP_TX
  bpf: introduce BPF_F_XDP_HAS_FRAGS flag in prog_flags loading the ebpf
    program
  net: mvneta: enable jumbo frames if the loaded XDP program support
    frags
  bpf: introduce bpf_xdp_get_buff_len helper
  bpf: move user_size out of bpf_test_init
  bpf: introduce frags support to bpf_prog_test_run_xdp()
  bpf: test_run: add xdp_shared_info pointer in bpf_test_finish
    signature
  libbpf: Add SEC name for xdp frags programs
  net: xdp: introduce bpf_xdp_pointer utility routine
  bpf: selftests: introduce bpf_xdp_{load,store}_bytes selftest
  bpf: selftests: add CPUMAP/DEVMAP selftests for xdp frags
  xdp: disable XDP_REDIRECT for xdp frags
====================

Signed-off-by: Alexei Starovoitov <ast@kernel.org>

XDP_REDIRECT is not fully supported yet for xdp frags since not
all XDP capable drivers can map non-linear xdp_frame in ndo_xdp_xmit
so disable it for the moment.

Acked-by: Toke Hoiland-Jorgensen <toke@redhat.com>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Acked-by: Jesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
Link: https://lore.kernel.org/r/0da25e117d0e2673f5d0ce6503393c55c6fb1be9.1642758637.git.lorenzo@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

Verify compatibility checks attaching a XDP frags program to a
CPUMAP/DEVMAP

Acked-by: Toke Hoiland-Jorgensen <toke@redhat.com>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
Link: https://lore.kernel.org/r/d94b4d35adc1e42c9ca5004e6b2cdfd75992304d.1642758637.git.lorenzo@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

Introduce kernel selftest for new bpf_xdp_{load,store}_bytes helpers.
and bpf_xdp_pointer/bpf_xdp_copy_buf utility routines.

Acked-by: Toke Hoiland-Jorgensen <toke@redhat.com>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
Link: https://lore.kernel.org/r/2c99ae663a5dcfbd9240b1d0489ad55dea4f4601.1642758637.git.lorenzo@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

Similar to skb_header_pointer, introduce bpf_xdp_pointer utility routine
to return a pointer to a given position in the xdp_buff if the requested
area (offset + len) is contained in a contiguous memory area otherwise it
will be copied in a bounce buffer provided by the caller.
Similar to the tc counterpart, introduce the two following xdp helpers:
- bpf_xdp_load_bytes
- bpf_xdp_store_bytes

Reviewed-by: Eelco Chaudron <echaudro@redhat.com>
Acked-by: Toke Hoiland-Jorgensen <toke@redhat.com>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Acked-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
Link: https://lore.kernel.org/r/ab285c1efdd5b7a9d361348b1e7d3ef49f6382b3.1642758637.git.lorenzo@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

The check for tail call map compatibility ensures that tail calls only
happen between maps of the same type. To ensure backwards compatibility for
XDP frags we need a similar type of check for cpumap and devmap
programs, so move the state from bpf_array_aux into bpf_map, add
xdp_has_frags to the check, and apply the same check to cpumap and devmap.

Acked-by: John Fastabend <john.fastabend@gmail.com>
Co-developed-by: Lorenzo Bianconi <lorenzo@kernel.org>
Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
Signed-off-by: Toke Hoiland-Jorgensen <toke@redhat.com>
Link: https://lore.kernel.org/r/f19fd97c0328a39927f3ad03e1ca6b43fd53cdfd.1642758637.git.lorenzo@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

Introduce support for the following SEC entries for XDP frags
property:
- SEC("xdp.frags")
- SEC("xdp.frags/devmap")
- SEC("xdp.frags/cpumap")

Acked-by: Toke Hoiland-Jorgensen <toke@redhat.com>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
Link: https://lore.kernel.org/r/af23b6e4841c171ad1af01917839b77847a4bc27.1642758637.git.lorenzo@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

This change adds test cases for the xdp frags scenarios when shrinking
and growing.

Acked-by: Toke Hoiland-Jorgensen <toke@redhat.com>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Co-developed-by: Lorenzo Bianconi <lorenzo@kernel.org>
Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
Signed-off-by: Eelco Chaudron <echaudro@redhat.com>
Link: https://lore.kernel.org/r/d2e6a0ebc52db6f89e62b9befe045032e5e0a5fe.1642758637.git.lorenzo@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

introduce xdp_shared_info pointer in bpf_test_finish signature in order
to copy back paged data from a xdp frags frame to userspace buffer

Acked-by: Toke Hoiland-Jorgensen <toke@redhat.com>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
Link: https://lore.kernel.org/r/c803673798c786f915bcdd6c9338edaa9740d3d6.1642758637.git.lorenzo@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

Introduce the capability to allocate a xdp frags in
bpf_prog_test_run_xdp routine. This is a preliminary patch to
introduce the selftests for new xdp frags ebpf helpers

Acked-by: Toke Hoiland-Jorgensen <toke@redhat.com>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
Link: https://lore.kernel.org/r/b7c0e425a9287f00f601c4fc0de54738ec6ceeea.1642758637.git.lorenzo@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

Rely on data_size_in in bpf_test_init routine signature. This is a
preliminary patch to introduce xdp frags selftest

Acked-by: Toke Hoiland-Jorgensen <toke@redhat.com>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
Link: https://lore.kernel.org/r/6b48d38ed3d60240d7d6bb15e6fa7fabfac8dfb2.1642758637.git.lorenzo@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

This patch adds support for frags for the following helpers:
  - bpf_xdp_output()
  - bpf_perf_event_output()

Acked-by: Toke Hoiland-Jorgensen <toke@redhat.com>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Acked-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Eelco Chaudron <echaudro@redhat.com>
Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
Link: https://lore.kernel.org/r/340b4a99cdc24337b40eaf8bb597f9f9e7b0373e.1642758637.git.lorenzo@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

This change adds support for tail growing and shrinking for XDP frags.

When called on a non-linear packet with a grow request, it will work
on the last fragment of the packet. So the maximum grow size is the
last fragments tailroom, i.e. no new buffer will be allocated.
A XDP frags capable driver is expected to set frag_size in xdp_rxq_info
data structure to notify the XDP core the fragment size.
frag_size set to 0 is interpreted by the XDP core as tail growing is
not allowed.
Introduce __xdp_rxq_info_reg utility routine to initialize frag_size field.

When shrinking, it will work from the last fragment, all the way down to
the base buffer depending on the shrinking size. It's important to mention
that once you shrink down the fragment(s) are freed, so you can not grow
again to the original size.

Acked-by: Toke Hoiland-Jorgensen <toke@redhat.com>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Acked-by: Jakub Kicinski <kuba@kernel.org>
Co-developed-by: Lorenzo Bianconi <lorenzo@kernel.org>
Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
Signed-off-by: Eelco Chaudron <echaudro@redhat.com>
Link: https://lore.kernel.org/r/eabda3485dda4f2f158b477729337327e609461d.1642758637.git.lorenzo@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

Introduce bpf_xdp_get_buff_len helper in order to return the xdp buffer
total size (linear and paged area)

Acked-by: Toke Hoiland-Jorgensen <toke@redhat.com>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
Link: https://lore.kernel.org/r/aac9ac3504c84026cf66a3c71b7c5ae89bc991be.1642758637.git.lorenzo@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

Enable the capability to receive jumbo frames even if the interface is
running in XDP mode if the loaded program declare to properly support
xdp frags. At same time reject a xdp program not supporting xdp frags
if the driver is running in xdp frags mode.

Acked-by: Toke Hoiland-Jorgensen <toke@redhat.com>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
Link: https://lore.kernel.org/r/6909f81a3cbb8fb6b88e914752c26395771b882a.1642758637.git.lorenzo@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

Introduce BPF_F_XDP_HAS_FRAGS and the related field in bpf_prog_aux
in order to notify the driver the loaded program support xdp frags.

Acked-by: Toke Hoiland-Jorgensen <toke@redhat.com>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
Link: https://lore.kernel.org/r/db2e8075b7032a356003f407d1b0deb99adaa0ed.1642758637.git.lorenzo@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

Introduce the capability to map non-linear xdp buffer running
mvneta_xdp_submit_frame() for XDP_TX and XDP_REDIRECT

Acked-by: Toke Hoiland-Jorgensen <toke@redhat.com>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
Link: https://lore.kernel.org/r/5d46ab63870ffe96fb95e6075a7ff0c81ef6424d.1642758637.git.lorenzo@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

Take into account if the received xdp_buff/xdp_frame is non-linear
recycling/returning the frame memory to the allocator or into
xdp_frame_bulk.

Acked-by: Toke Hoiland-Jorgensen <toke@redhat.com>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
Link: https://lore.kernel.org/r/a961069febc868508ce1bdf5e53a343eb4e57cb2.1642758637.git.lorenzo@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

Rely on xdp_update_skb_shared_info routine in order to avoid
resetting frags array in skb_shared_info structure building
the skb in mvneta_swbm_build_skb(). Frags array is expected to
be initialized by the receiving driver building the xdp_buff
and here we just need to update memory metadata.

Acked-by: Toke Hoiland-Jorgensen <toke@redhat.com>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
Link: https://lore.kernel.org/r/e0dad97f5d02b13f189f99f1e5bc8e61bef73412.1642758637.git.lorenzo@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

Introduce xdp_update_skb_shared_info routine to update frags array
metadata in skb_shared_info data structure converting to a skb from
a xdp_buff or xdp_frame.
According to the current skb_shared_info architecture in
xdp_frame/xdp_buff and to the xdp frags support, there is
no need to run skb_add_rx_frag() and reset frags array converting the buffer
to a skb since the frag array will be in the same position for xdp_buff/xdp_frame
and for the skb, we just need to update memory metadata.
Introduce XDP_FLAGS_PF_MEMALLOC flag in xdp_buff_flags in order to mark
the xdp_buff or xdp_frame as under memory-pressure if pages of the frags array
are under memory pressure. Doing so we can avoid looping over all fragments in
xdp_update_skb_shared_info routine. The driver is expected to set the
flag constructing the xdp_buffer using xdp_buff_set_frag_pfmemalloc
utility routine.
Rely on xdp_update_skb_shared_info in __xdp_build_skb_from_frame routine
converting the non-linear xdp_frame to a skb after performing a XDP_REDIRECT.

Acked-by: Toke Hoiland-Jorgensen <toke@redhat.com>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Acked-by: Jesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
Link: https://lore.kernel.org/r/bfd23fb8a8d7438724f7819c567cdf99ffd6226f.1642758637.git.lorenzo@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

Relying on xdp frags bit, remove skb_shared_info structure
allocated on the stack in mvneta_rx_swbm routine and simplify
mvneta_swbm_add_rx_fragment accessing skb_shared_info in the
xdp_buff structure directly. There is no performance penalty in
this approach since mvneta_swbm_add_rx_fragment is run just
for xdp frags use-case.

Acked-by: Toke Hoiland-Jorgensen <toke@redhat.com>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
Link: https://lore.kernel.org/r/45f050c094ccffce49d6bc5112939ed35250ba90.1642758637.git.lorenzo@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

Update frags bit (XDP_FLAGS_HAS_FRAGS) in xdp_buff to notify
XDP/eBPF layer and XDP remote drivers if this is a "non-linear"
XDP buffer. Access skb_shared_info only if XDP_FLAGS_HAS_FRAGS flag
is set in order to avoid possible cache-misses.

Acked-by: Toke Hoiland-Jorgensen <toke@redhat.com>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
Link: https://lore.kernel.org/r/c00a73097f8a35860d50dae4a36e6cc9ef7e172f.1642758637.git.lorenzo@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

Introduce flags field in xdp_frame and xdp_buffer data structures
to define additional buffer features. At the moment the only
supported buffer feature is frags bit (XDP_FLAGS_HAS_FRAGS).
frags bit is used to specify if this is a linear buffer
(XDP_FLAGS_HAS_FRAGS not set) or a frags frame (XDP_FLAGS_HAS_FRAGS
set). In the latter case the driver is expected to initialize the
skb_shared_info structure at the end of the first buffer to link together
subsequent buffers belonging to the same frame.

Acked-by: Toke Hoiland-Jorgensen <toke@redhat.com>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Acked-by: Jesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
Link: https://lore.kernel.org/r/e389f14f3a162c0a5bc6a2e1aa8dd01a90be117d.1642758637.git.lorenzo@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

Introduce xdp_frags_size field in skb_shared_info data structure
to store xdp_buff/xdp_frame frame paged size (xdp_frags_size will
be used in xdp frags support). In order to not increase
skb_shared_info size we will use a hole due to skb_shared_info
alignment.

Acked-by: Toke Hoiland-Jorgensen <toke@redhat.com>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Acked-by: Jesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
Link: https://lore.kernel.org/r/8a849819a3e0a143d540f78a3a5add76e17e980d.1642758637.git.lorenzo@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

Add test for querying progs attached to sockmap. we use an existing
libbpf query interface to query prog cnt before and after progs
attaching to sockmap and check whether the queried prog id is right.

Signed-off-by: Di Zhu <zhudi2@huawei.com>
Acked-by: Yonghong Song <yhs@fb.com>
Reviewed-by: Jakub Sitnicki <jakub@cloudflare.com>
Link: https://lore.kernel.org/r/20220119014005.1209-2-zhudi2@huawei.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

Right now there is no way to query whether BPF programs are
attached to a sockmap or not.

we can use the standard interface in libbpf to query, such as:
bpf_prog_query(mapFd, BPF_SK_SKB_STREAM_PARSER, 0, NULL, ...);
the mapFd is the fd of sockmap.

Signed-off-by: Di Zhu <zhudi2@huawei.com>
Acked-by: Yonghong Song <yhs@fb.com>
Reviewed-by: Jakub Sitnicki <jakub@cloudflare.com>
Link: https://lore.kernel.org/r/20220119014005.1209-1-zhudi2@huawei.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

Andrii Nakryiko says:

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

Revamp existing low-level XDP APIs provided by libbpf to follow more
consistent naming (new APIs follow bpf_tc_xxx() approach where it makes
sense) and be extensible without ABI breakages (OPTS-based). See patch #1 for
details, remaining patches switch bpftool, selftests/bpf and samples/bpf to
new APIs.
====================

Signed-off-by: Alexei Starovoitov <ast@kernel.org>

Use new bpf_xdp_*() APIs across all XDP-related BPF samples.

Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20220120061422.2710637-5-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

Switch to using new bpf_xdp_*() APIs across all selftests. Take
advantage of a more straightforward and user-friendly semantics of
old_prog_fd (0 means "don't care") in few places.

Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20220120061422.2710637-4-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

Switch to new bpf_xdp_attach() API to avoid deprecation warnings.

Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20220120061422.2710637-3-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

Introduce 4 new netlink-based XDP APIs for attaching, detaching, and
querying XDP programs:
  - bpf_xdp_attach;
  - bpf_xdp_detach;
  - bpf_xdp_query;
  - bpf_xdp_query_id.

These APIs replace bpf_set_link_xdp_fd, bpf_set_link_xdp_fd_opts,
bpf_get_link_xdp_id, and bpf_get_link_xdp_info APIs ([0]). The latter
don't follow a consistent naming pattern and some of them use
non-extensible approaches (e.g., struct xdp_link_info which can't be
modified without breaking libbpf ABI).

The approach I took with these low-level XDP APIs is similar to what we
did with low-level TC APIs. There is a nice duality of bpf_tc_attach vs
bpf_xdp_attach, and so on. I left bpf_xdp_attach() to support detaching
when -1 is specified for prog_fd for generality and convenience, but
bpf_xdp_detach() is preferred due to clearer naming and associated
semantics. Both bpf_xdp_attach() and bpf_xdp_detach() accept the same
opts struct allowing to specify expected old_prog_fd.

While doing the refactoring, I noticed that old APIs require users to
specify opts with old_fd == -1 to declare "don't care about already
attached XDP prog fd" condition. Otherwise, FD 0 is assumed, which is
essentially never an intended behavior. So I made this behavior
consistent with other kernel and libbpf APIs, in which zero FD means "no
FD". This seems to be more in line with the latest thinking in BPF land
and should cause less user confusion, hopefully.

For querying, I left two APIs, both more generic bpf_xdp_query()
allowing to query multiple IDs and attach mode, but also
a specialization of it, bpf_xdp_query_id(), which returns only requested
prog_id. Uses of prog_id returning bpf_get_link_xdp_id() were so
prevalent across selftests and samples, that it seemed a very common use
case and using bpf_xdp_query() for doing it felt very cumbersome with
a highly branches if/else chain based on flags and attach mode.

Old APIs are scheduled for deprecation in libbpf 0.8 release.

  [0] Closes: https://github.com/libbpf/libbpf/issues/309

Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Toke Høiland-Jørgensen <toke@redhat.com>
Link: https://lore.kernel.org/r/20220120061422.2710637-2-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

Andrii Nakryiko says:

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

Officially deprecate legacy BPF map definitions in libbpf. They've been slated
for deprecation for a while in favor of more powerful BTF-defined map
definitions and this patch set adds warnings and a way to enforce this in
libbpf through LIBBPF_STRICT_MAP_DEFINITIONS strict mode flag.

Selftests are fixed up and updated, BPF documentation is updated, bpftool's
strict mode usage is adjusted to avoid breaking users unnecessarily.

v1->v2:
  - replace missed bpf_map_def case in Documentation/bpf/btf.rst (Alexei).
====================

Signed-off-by: Alexei Starovoitov <ast@kernel.org>

Use BTF-defined map definition in the documentation example.

Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20220120060529.1890907-5-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

Enact deprecation of legacy BPF map definition in SEC("maps") ([0]). For
the definitions themselves introduce LIBBPF_STRICT_MAP_DEFINITIONS flag
for libbpf strict mode. If it is set, error out on any struct
bpf_map_def-based map definition. If not set, libbpf will print out
a warning for each legacy BPF map to raise awareness that it goes away.

For any use of BPF_ANNOTATE_KV_PAIR() macro providing a legacy way to
associate BTF key/value type information with legacy BPF map definition,
warn through libbpf's pr_warn() error message (but don't fail BPF object
open).

BPF-side struct bpf_map_def is marked as deprecated. User-space struct
bpf_map_def has to be used internally in libbpf, so it is left
untouched. It should be enough for bpf_map__def() to be marked
deprecated to raise awareness that it goes away.

bpftool is an interesting case that utilizes libbpf to open BPF ELF
object to generate skeleton. As such, even though bpftool itself uses
full on strict libbpf mode (LIBBPF_STRICT_ALL), it has to relax it a bit
for BPF map definition handling to minimize unnecessary disruptions. So
opt-out of LIBBPF_STRICT_MAP_DEFINITIONS for bpftool. User's code that
will later use generated skeleton will make its own decision whether to
enforce LIBBPF_STRICT_MAP_DEFINITIONS or not.

There are few tests in selftests/bpf that are consciously using legacy
BPF map definitions to test libbpf functionality. For those, temporary
opt out of LIBBPF_STRICT_MAP_DEFINITIONS mode for the duration of those
tests.

  [0] Closes: https://github.com/libbpf/libbpf/issues/272

Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20220120060529.1890907-4-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

Converted few remaining legacy BPF map definition to BTF-defined ones.
For the remaining two bpf_map_def-based legacy definitions that we want
to keep for testing purposes until libbpf 1.0 release, guard them in
pragma to suppres deprecation warnings which will be added in libbpf in
the next commit.

Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20220120060529.1890907-3-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

It's very easy to miss compilation warnings without -Werror, which is
not set for selftests. libbpf and bpftool are already strict about this,
so make selftests/bpf also treat compilation warnings as errors to catch
such regressions early.

Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20220120060529.1890907-2-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

Some users have complained that selftests fail to build when
CONFIG_NF_CONNTRACK=m. It would be useful to allow building as long as
it is set to module or built-in, even though in case of building as
module, user would need to load it before running the selftest. Note
that this also allows building selftest when CONFIG_NF_CONNTRACK is
disabled.

Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20220120164932.2798544-1-memxor@gmail.com

The bind_perm BPF selftest failed when port 111/tcp was already in use
during the test. To fix this, the test now runs in its own network name
space.

To use unshare, it is necessary to reorder the includes. The style of
the includes is adapted to be consistent with the other prog_tests.

v2: Replace deprecated CHECK macro with ASSERT_OK

Fixes: 8259fdeb

 ("selftests/bpf: Verify that rebinding to port < 1024 from BPF works")
Signed-off-by: Felix Maurer <fmaurer@redhat.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Reviewed-by: Jakub Sitnicki <jakub@cloudflare.com>
Link: https://lore.kernel.org/bpf/551ee65533bb987a43f93d88eaf2368b416ccd32.1642518457.git.fmaurer@redhat.com

Lorenzo Bianconi says:

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

Rely on ASSERT* macros and get rid of deprecated CHECK ones in xdp_bpf2bpf and
xdp_adjust_tail bpf selftests.
This is a preliminary series for XDP multi-frags support.

Changes since v1:
- run each ASSERT test separately
- drop unnecessary return statements
- drop unnecessary if condition in test_xdp_bpf2bpf()
====================

Signed-off-by: Andrii Nakryiko <andrii@kernel.org>