This commit adds xsk_fwd test file to .gitignore which is newly added
to samples/bpf.
Signed-off-by: Daniel T. Lee <danieltimlee@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20200904063434.24963-2-danieltimlee@gmail.com

From commit 52109584 ("libbpf: Deprecate notion of BPF program
"title" in favor of "section name""), the term title has been replaced
with section name in libbpf.

Since the bpf_program__title() has been deprecated, this commit
switches this function to bpf_program__section_name(). Due to
this commit, the compilation warning issue has also been resolved.

Fixes: 52109584 ("libbpf: Deprecate notion of BPF program "title" in favor of "section name"")
Signed-off-by: Daniel T. Lee <danieltimlee@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20200904063434.24963-1-danieltimlee@gmail.com

Detected by LGTM static analyze in Github repo, fix potential multiplication
overflow before result is casted to size_t.

Fixes: 8505e870 ("libbpf: Implement generalized .BTF.ext func/line info adjustment")
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20200904041611.1695163-2-andriin@fb.com

Another issue of __u64 needing either %lu or %llu, depending on the
architecture. Fix with cast to `unsigned long long`.

Fixes: 7e06aad5 ("libbpf: Add multi-prog section support for struct_ops")
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20200904041611.1695163-1-andriin@fb.com

The returned value of bpf_object__open_file() should be checked with
libbpf_get_error() rather than NULL. This fix prevents test_progs from
crash when test_global_data.o is not present.
Signed-off-by: Hao Luo <haoluo@google.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/20200903200528.747884-1-haoluo@google.com

Andrii Nakryiko says:

====================
Currently, libbpf supports a limited form of BPF-to-BPF subprogram calls. The
restriction is that entry-point BPF program should use *all* of defined
sub-programs in BPF .o file. If any of the subprograms is not used, such
entry-point BPF program will be rejected by verifier as containing unreachable
dead code. This is not a big limitation for cases with single entry-point BPF
programs, but is quite a heavy restriction for multi-programs that use only
partially overlapping set of subprograms.

This patch set removes all such restrictions and adds complete support for
using BPF sub-program calls on BPF side. This is achieved through libbpf
tracking subprograms individually and detecting which subprograms are used by
any given entry-point BPF program, and subsequently only appending and
relocating code for just those used subprograms.

In addition, libbpf now also supports multiple entry-point BPF programs within
the same ELF section. This allows to structure code so that there are few
variants of BPF programs of the same type and attaching to the same target
(e.g., for tracepoints and kprobes) without the need to worry about ELF
section name clashes.

This patch set opens way for more wider adoption of BPF subprogram calls,
especially for real-world production use-cases with complicated net of
subprograms. This will allow to further scale BPF verification process through
good use of global functions, which can be verified independently. This is
also important prerequisite for static linking which allows static BPF
libraries to not worry about naming clashes for section names, as well as use
static non-inlined functions (subprograms) without worries of verifier
rejecting program due to dead code.

Patch set is structured as follows:
- patched 1-6 contain all the libbpf changes necessary to support multi-prog
  sections and bpf2bpf subcalls;
- patch 7 adds dedicated selftests validating all combinations of possible
  sub-calls (within and across sections, static vs global functions);
- patch 8 deprecated bpf_program__title() in favor of
  bpf_program__section_name(). The intent was to also deprecate
  bpf_object__find_program_by_title() as it's now non-sensical with multiple
  programs per section. But there were too many selftests uses of this and
  I didn't want to delay this patches further and make it even bigger, so left
  it for a follow up cleanup;
- patches 9-10 remove uses for title-related APIs from bpftool and
  bpf_program__title() use from selftests;
- patch 11 is converting fexit_bpf2bpf to have explicit subtest (it does
  contain 4 subtests, which are not handled as sub-tests);
- patches 12-14 convert few complicated BPF selftests to use __noinline
  functions to further validate correctness of libbpf's bpf2bpf processing
  logic.

v2->v3:
  - explained subprog relocation algorithm in more details (Alexei);
  - pyperf, strobelight and cls_redirect got new subprog variants, leaving
    other modes intact (Alexei);
v1->v2:
  - rename DEPRECATED to LIBBPF_DEPRECATED to avoid name clashes;
  - fix test_subprogs build;
  - convert a bunch of complicated selftests to __noinline (Alexei).
====================
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

As one of the most complicated and close-to-real-world programs, cls_redirect
is a good candidate to exercise libbpf's logic of handling bpf2bpf calls. So
add variant with using explicit __noinline for majority of functions except
few most basic ones. If those few functions are inlined, verifier starts to
complain about program instruction limit of 1mln instructions being exceeded,
most probably due to instruction overhead of doing a sub-program call.
Convert user-space part of selftest to have to sub-tests: with and without
inlining.
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Cc: Lorenz Bauer <lmb@cloudflare.com>
Link: https://lore.kernel.org/bpf/20200903203542.15944-15-andriin@fb.com

Update xdp_noinline to use BPF skeleton and force __noinline on helper
sub-programs. Also, split existing logic into v4- and v6-only to complicate
sub-program calling patterns (partially overlapped sets of functions for
entry-level BPF programs).
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200903203542.15944-14-andriin@fb.com

Add use of non-inlined subprogs to few bigger selftests to excercise libbpf's
bpf2bpf handling logic. Also split l4lb_all selftest into two sub-tests.
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200903203542.15944-13-andriin@fb.com

There are clearly 4 subtests, so make it official.
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200903203542.15944-12-andriin@fb.com

BPF program title is ambigious and misleading term. It is ELF section name, so
let's just call it that and deprecate bpf_program__title() API in favor of
bpf_program__section_name().

Additionally, using bpf_object__find_program_by_title() is now inherently
dangerous and ambiguous, as multiple BPF program can have the same section
name. So deprecate this API as well and recommend to switch to non-ambiguous
bpf_object__find_program_by_name().

Internally, clean up usage and mis-usage of BPF program section name for
denoting BPF program name. Shorten the field name to prog->sec_name to be
consistent with all other prog->sec_* variables.
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200903203542.15944-11-andriin@fb.com

Remove all uses of bpf_program__title() and
bpf_program__find_program_by_title().
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200903203542.15944-10-andriin@fb.com

bpf_program__title() is deprecated, switch to bpf_program__section_name() and
avoid compilation warnings.
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200903203542.15944-9-andriin@fb.com

Add a selftest excercising bpf-to-bpf subprogram calls, as well as multiple
entry-point BPF programs per section. Also make sure that BPF CO-RE works for
such set ups both for sub-programs and for multi-entry sections.
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200903203542.15944-8-andriin@fb.com

Adjust struct_ops handling code to work with multi-program ELF sections
properly.
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200903203542.15944-7-andriin@fb.com

Complete multi-prog sections and multi sub-prog support in libbpf by properly
adjusting .BTF.ext's line and function information. Mark exposed
btf_ext__reloc_func_info() and btf_ext__reloc_func_info() APIs as deprecated.
These APIs have simplistic assumption that all sub-programs are going to be
appended to all main BPF programs, which doesn't hold in real life. It's
unlikely there are any users of this API, as it's very libbpf
internals-specific.
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200903203542.15944-6-andriin@fb.com

This patch implements general and correct logic for bpf-to-bpf sub-program
calls. Only sub-programs used (called into) from entry-point (main) BPF
program are going to be appended at the end of main BPF program. This ensures
that BPF verifier won't encounter any dead code due to copying unreferenced
sub-program. This change means that each entry-point (main) BPF program might
have a different set of sub-programs appended to it and potentially in
different order. This has implications on how sub-program call relocations
need to be handled, described below.

All relocations are now split into two categores: data references (maps and
global variables) and code references (sub-program calls). This distinction is
important because data references need to be relocated just once per each BPF
program and sub-program. These relocation are agnostic to instruction
locations, because they are not code-relative and they are relocating against
static targets (maps, variables with fixes offsets, etc).

Sub-program RELO_CALL relocations, on the other hand, are highly-dependent on
code position, because they are recorded as instruction-relative offset. So
BPF sub-programs (those that do calls into other sub-programs) can't be
relocated once, they need to be relocated each time such a sub-program is
appended at the end of the main entry-point BPF program. As mentioned above,
each main BPF program might have different subset and differen order of
sub-programs, so call relocations can't be done just once. Splitting data
reference and calls relocations as described above allows to do this
efficiently and cleanly.

bpf_object__find_program_by_name() will now ignore non-entry BPF programs.
Previously one could have looked up '.text' fake BPF program, but the
existence of such BPF program was always an implementation detail and you
can't do much useful with it. Now, though, all non-entry sub-programs get
their own BPF program with name corresponding to a function name, so there is
no more '.text' name for BPF program. This means there is no regression,
effectively, w.r.t.  API behavior. But this is important aspect to highlight,
because it's going to be critical once libbpf implements static linking of BPF
programs. Non-entry static BPF programs will be allowed to have conflicting
names, but global and main-entry BPF program names should be unique. Just like
with normal user-space linking process. So it's important to restrict this
aspect right now, keep static and non-entry functions as internal
implementation details, and not have to deal with regressions in behavior
later.

This patch leaves .BTF.ext adjustment as is until next patch.
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200903203542.15944-5-andriin@fb.com

Fix up CO-RE relocation code to handle relocations against ELF sections
containing multiple BPF programs. This requires lookup of a BPF program by its
section name and instruction index it contains. While it could have been done
as a simple loop, it could run into performance issues pretty quickly, as
number of CO-RE relocations can be quite large in real-world applications, and
each CO-RE relocation incurs BPF program look up now. So instead of simple
loop, implement a binary search by section name + insn offset.
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Link: https://lore.kernel.org/bpf/20200903203542.15944-4-andriin@fb.com

Teach libbpf how to parse code sections into potentially multiple bpf_program
instances, based on ELF FUNC symbols. Each BPF program will keep track of its
position within containing ELF section for translating section instruction
offsets into program instruction offsets: regardless of BPF program's location
in ELF section, it's first instruction is always at local instruction offset
0, so when libbpf is working with relocations (which use section-based
instruction offsets) this is critical to make proper translations.
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Link: https://lore.kernel.org/bpf/20200903203542.15944-3-andriin@fb.com

libbpf ELF parsing logic might need symbols available before ELF parsing is
completed, so we need to make sure that symbols table section is found in
a separate pass before all the subsequent sections are processed.
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Link: https://lore.kernel.org/bpf/20200903203542.15944-2-andriin@fb.com

Fix use-after-free when a shared umem bind fails. The code incorrectly
tried to free the allocated buffer pool both in the bind code and then
later also when the socket was released. Fix this by setting the
buffer pool pointer to NULL after the bind code has freed the pool, so
that the socket release code will not try to free the pool. This is
the same solution as the regular, non-shared umem code path has. This
was missing from the shared umem path.

Fixes: b5aea28d ("xsk: Add shared umem support between queue ids")
Reported-by: syzbot+5334f62e4d22804e646a@syzkaller.appspotmail.com
Signed-off-by: Magnus Karlsson <magnus.karlsson@intel.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/1599032164-25684-1-git-send-email-magnus.karlsson@intel.com

Currently, dma_map is being checked, when the right object identifier
to be null-checked is dma_map->dma_pages, instead.

Fix this by null-checking dma_map->dma_pages.

Fixes: 921b6869 ("xsk: Enable sharing of dma mappings")
Addresses-Coverity-ID: 1496811 ("Logically dead code")
Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Björn Töpel <bjorn.topel@intel.com>
Link: https://lore.kernel.org/bpf/20200902150750.GA7257@embeddedor

Fix possible segfault when entry is inserted into xskmap. This can
happen if the socket is in a state where the umem has been set up, the
Rx ring created but it has yet to be bound to a device. In this case
the pool has not yet been created and we cannot reference it for the
existence of the fill ring. Fix this by removing the whole
xsk_is_setup_for_bpf_map function. Once upon a time, it was used to
make sure that the Rx and fill rings where set up before the driver
could call xsk_rcv, since there are no tests for the existence of
these rings in the data path. But these days, we have a state variable
that we test instead. When it is XSK_BOUND, everything has been set up
correctly and the socket has been bound. So no reason to have the
xsk_is_setup_for_bpf_map function anymore.

Fixes: 7361f9c3 ("xsk: Move fill and completion rings to buffer pool")
Reported-by: syzbot+febe51d44243fbc564ee@syzkaller.appspotmail.com
Signed-off-by: Magnus Karlsson <magnus.karlsson@intel.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/1599037569-26690-1-git-send-email-magnus.karlsson@intel.com

Fix possible segfault in the xsk diagnostics code when dumping
information about the umem. This can happen when a umem has been
created, but the socket has not been bound yet. In this case, the xsk
buffer pool does not exist yet and we cannot dump the information
that was moved from the umem to the buffer pool. Fix this by testing
for the existence of the buffer pool and if not there, do not dump any
of that information.

Fixes: c2d3d6a4 ("xsk: Move queue_id, dev and need_wakeup to buffer pool")
Fixes: 7361f9c3 ("xsk: Move fill and completion rings to buffer pool")
Reported-by: syzbot+3f04d36b7336f7868066@syzkaller.appspotmail.com
Signed-off-by: Magnus Karlsson <magnus.karlsson@intel.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/1599036743-26454-1-git-send-email-magnus.karlsson@intel.com

Modified existing bpf_iter_test_file.c program to check whether
all accessed files from the main thread or not.

Modified existing bpf_iter_test_file program to check
whether all accessed files from the main thread or not.
  $ ./test_progs -n 4
  ...
  #4/7 task_file:OK
  ...
  #4 bpf_iter:OK
  Summary: 1/24 PASSED, 0 SKIPPED, 0 FAILED
Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/20200902023113.1672863-1-yhs@fb.com

Currently, task_file iterator iterates all files from all tasks.
This may potentially visit a lot of duplicated files if there are
many tasks sharing the same files, e.g., typical pthreads
where these pthreads and the main thread are sharing the same files.

This patch changed task_file iterator to skip a particular task
if that task shares the same files as its group_leader (the task
having the same tgid and also task->tgid == task->pid).
This will preserve the same result, visiting all files from all
tasks, and will reduce runtime cost significantl, e.g., if there are
a lot of pthreads and the process has a lot of open files.
Suggested-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Link: https://lore.kernel.org/bpf/20200902023112.1672792-1-yhs@fb.com

Ioana Ciornei says:

====================
dpaa2-eth: add a dpaa2_eth_ prefix to all functions

This is just a quick cleanup that aims at adding a dpaa2_eth_ prefix to
all functions within the dpaa2-eth driver even if those are static and
private to the driver. The main reason for doing this is that looking a
perf top, for example, is becoming an inconvenience because one cannot
easily determine which entries are dpaa2-eth related or not.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

Some static functions in the dpaa2-eth driver don't have the dpaa2_eth_
prefix and this is becoming an inconvenience when looking at, for
example, a perf top output and trying to determine easily which entries
are dpaa2-eth related. Ammend this by adding the prefix to all the
functions.
Signed-off-by: Ioana Ciornei <ioana.ciornei@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Some static functions in the dpaa2-eth driver don't have the dpaa2_eth_
prefix and this is becoming an inconvenience when looking at, for
example, a perf top output and trying to determine easily which entries
are dpaa2-eth related. Ammend this by adding the prefix to all the
functions.
Signed-off-by: Ioana Ciornei <ioana.ciornei@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Some static functions in the dpaa2-eth driver don't have the dpaa2_eth_
prefix and this is becoming an inconvenience when looking at, for
example, a perf top output and trying to determine easily which entries
are dpaa2-eth related. Ammend this by adding the prefix to all the
functions.
Signed-off-by: Ioana Ciornei <ioana.ciornei@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

If nf_conncount_init fails currently the dispatched work is not canceled,
causing problems when the timer fires. This change fixes this by not
scheduling the work until all initialization is successful.

Fixes: a65878d6 ("net: openvswitch: fixes potential deadlock in dp cleanup code")
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Eelco Chaudron <echaudro@redhat.com>
Reviewed-by: Tonghao Zhang <xiangxia.m.yue@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

In some cases, the device or firmware may be busy when the
driver attempts to perform the CRQ initialization handshake.
If the partner is busy, the hypervisor will return the H_CLOSED
return code. The aim of this patch is that, if the device is not
ready, to query the device a number of times, with a small wait
time in between queries. If all initialization requests fail,
the driver will remain in a dormant state, awaiting a signal
from the device that it is ready for operation.
Signed-off-by: Thomas Falcon <tlfalcon@linux.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Daniel Borkmann says:

====================
pull-request: bpf-next 2020-09-01

The following pull-request contains BPF updates for your *net-next* tree.

There are two small conflicts when pulling, resolve as follows:

1) Merge conflict in tools/lib/bpf/libbpf.c between 88a82120 ("libbpf: Factor
   out common ELF operations and improve logging") in bpf-next and 1e891e51
   ("libbpf: Fix map index used in error message") in net-next. Resolve by taking
   the hunk in bpf-next:

        [...]
        scn = elf_sec_by_idx(obj, obj->efile.btf_maps_shndx);
        data = elf_sec_data(obj, scn);
        if (!scn || !data) {
                pr_warn("elf: failed to get %s map definitions for %s\n",
                        MAPS_ELF_SEC, obj->path);
                return -EINVAL;
        }
        [...]

2) Merge conflict in drivers/net/ethernet/mellanox/mlx5/core/en/xsk/rx.c between
   9647c57b ("xsk: i40e: ice: ixgbe: mlx5: Test for dma_need_sync earlier for
   better performance") in bpf-next and e20f0dbf ("net/mlx5e: RX, Add a prefetch
   command for small L1_CACHE_BYTES") in net-next. Resolve the two locations by retaining
   net_prefetch() and taking xsk_buff_dma_sync_for_cpu() from bpf-next. Should look like:

        [...]
        xdp_set_data_meta_invalid(xdp);
        xsk_buff_dma_sync_for_cpu(xdp, rq->xsk_pool);
        net_prefetch(xdp->data);
        [...]

We've added 133 non-merge commits during the last 14 day(s) which contain
a total of 246 files changed, 13832 insertions(+), 3105 deletions(-).

The main changes are:

1) Initial support for sleepable BPF programs along with bpf_copy_from_user() helper
   for tracing to reliably access user memory, from Alexei Starovoitov.

2) Add BPF infra for writing and parsing TCP header options, from Martin KaFai Lau.

3) bpf_d_path() helper for returning full path for given 'struct path', from Jiri Olsa.

4) AF_XDP support for shared umems between devices and queues, from Magnus Karlsson.

5) Initial prep work for full BPF-to-BPF call support in libbpf, from Andrii Nakryiko.

6) Generalize bpf_sk_storage map & add local storage for inodes, from KP Singh.

7) Implement sockmap/hash updates from BPF context, from Lorenz Bauer.

8) BPF xor verification for scalar types & add BPF link iterator, from Yonghong Song.

9) Use target's prog type for BPF_PROG_TYPE_EXT prog verification, from Udip Pant.

10) Rework BPF tracing samples to use libbpf loader, from Daniel T. Lee.

11) Fix xdpsock sample to really cycle through all buffers, from Weqaar Janjua.

12) Improve type safety for tun/veth XDP frame handling, from Maciej Żenczykowski.

13) Various smaller cleanups and improvements all over the place.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

Remove unneeded return value cast.
This is detected by coccinelle.
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Remove dma_alloc_coherent return value cast.
This is detected by coccinelle.
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Implement the getsockopt SOL_TLS TLS_RX which is currently missing. The
primary usecase is to use it in conjunction with TCP_REPAIR to
checkpoint/restore the TLS record layer state.

TLS connection state usually exists on the user space library. So
basically we can easily extract it from there, but when the TLS
connections are delegated to the kTLS, it is not the case. We need to
have a way to extract the TLS state from the kernel for both of TX and
RX side.

The new TLS_RX getsockopt copies the crypto_info to user in the same
way as TLS_TX does.

We have described use cases in our research work in Netdev 0x14
Transport Workshop [1].

Also, there is an TLS implementation called tlse [2] which supports
TLS connection migration. They have support of kTLS and their code
shows that they are expecting the future support of this option.

[1] https://speakerdeck.com/yutarohayakawa/prism-proxies-without-the-pain
[2] https://github.com/eduardsui/tlseSigned-off-by: Yutaro Hayakawa <yhayakawa3720@gmail.com>
Reviewed-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

Tonghao Zhang says:

====================
net: openvswitch: improve the codes

This series patches are not bug fix, just improve codes.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

keep_flows was introduced by [1], which used as flag to delete flows or not.
When rehashing or expanding the table instance, we will not flush the flows.
Now don't use it anymore, remove it.

[1] - https://github.com/openvswitch/ovs/commit/acd051f1761569205827dc9b037e15568a8d59f8
Cc: Pravin B Shelar <pshelar@ovn.org>
Signed-off-by: Tonghao Zhang <xiangxia.m.yue@gmail.com>
Acked-by: Pravin B Shelar <pshelar@ovn.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

Decrease table->count and ufid_count unconditionally,
because we only don't use count or ufid_count to count
when flushing the flows. To simplify the codes, we
remove the "count" argument of table_instance_flow_free.

To avoid a bug when deleting flows in the future, add
WARN_ON in flush flows function.

Cc: Pravin B Shelar <pshelar@ovn.org>
Signed-off-by: Tonghao Zhang <xiangxia.m.yue@gmail.com>
Acked-by: Pravin B Shelar <pshelar@ovn.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

Not change the logic, just improve the coding style.

Cc: Pravin B Shelar <pshelar@ovn.org>
Signed-off-by: Tonghao Zhang <xiangxia.m.yue@gmail.com>
Acked-by: Pravin B Shelar <pshelar@ovn.org>
Signed-off-by: David S. Miller <davem@davemloft.net>