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From:   Lorenz Bauer <lmb@isovalent.com>
Subject: [PATCH bpf-next v6 0/8] Add SO_REUSEPORT support for TC
 bpf_sk_assign
Date:   Thu, 20 Jul 2023 17:30:04 +0200
Message-Id: <20230720-so-reuseport-v6-0-7021b683cdae@isovalent.com>
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To:     "David S. Miller" <davem@davemloft.net>,
        Eric Dumazet <edumazet@google.com>,
        Jakub Kicinski <kuba@kernel.org>,
        Paolo Abeni <pabeni@redhat.com>,
        David Ahern <dsahern@kernel.org>,
        Willem de Bruijn <willemdebruijn.kernel@gmail.com>,
        Alexei Starovoitov <ast@kernel.org>,
        Daniel Borkmann <daniel@iogearbox.net>,
        Andrii Nakryiko <andrii@kernel.org>,
        Martin KaFai Lau <martin.lau@linux.dev>,
        Song Liu <song@kernel.org>, Yonghong Song <yhs@fb.com>,
        John Fastabend <john.fastabend@gmail.com>,
        KP Singh <kpsingh@kernel.org>,
        Stanislav Fomichev <sdf@google.com>,
        Hao Luo <haoluo@google.com>, Jiri Olsa <jolsa@kernel.org>,
        Joe Stringer <joe@wand.net.nz>,
        Mykola Lysenko <mykolal@fb.com>, Shuah Khan <shuah@kernel.org>,
        Kuniyuki Iwashima <kuniyu@amazon.com>
Cc:     Hemanth Malla <hemanthmalla@gmail.com>, netdev@vger.kernel.org,
        linux-kernel@vger.kernel.org, bpf@vger.kernel.org,
        linux-kselftest@vger.kernel.org, Lorenz Bauer <lmb@isovalent.com>,
        Joe Stringer <joe@cilium.io>
Precedence: bulk

We want to replace iptables TPROXY with a BPF program at TC ingress.
To make this work in all cases we need to assign a SO_REUSEPORT socket
to an skb, which is currently prohibited. This series adds support for
such sockets to bpf_sk_assing.

I did some refactoring to cut down on the amount of duplicate code. The
key to this is to use INDIRECT_CALL in the reuseport helpers. To show
that this approach is not just beneficial to TC sk_assign I removed
duplicate code for bpf_sk_lookup as well.

Joint work with Daniel Borkmann.

Signed-off-by: Lorenz Bauer <lmb@isovalent.com>
---
Changes in v6:
- Reject unhashed UDP sockets in bpf_sk_assign to avoid ref leak
- Link to v5: https://lore.kernel.org/r/20230613-so-reuseport-v5-0-f6686a0dbce0@isovalent.com

Changes in v5:
- Drop reuse_sk == sk check in inet[6]_steal_stock (Kuniyuki)
- Link to v4: https://lore.kernel.org/r/20230613-so-reuseport-v4-0-4ece76708bba@isovalent.com

Changes in v4:
- WARN_ON_ONCE if reuseport socket is refcounted (Kuniyuki)
- Use inet[6]_ehashfn_t to shorten function declarations (Kuniyuki)
- Shuffle documentation patch around (Kuniyuki)
- Update commit message to explain why IPv6 needs EXPORT_SYMBOL
- Link to v3: https://lore.kernel.org/r/20230613-so-reuseport-v3-0-907b4cbb7b99@isovalent.com

Changes in v3:
- Fix warning re udp_ehashfn and udp6_ehashfn (Simon)
- Return higher scoring connected UDP reuseport sockets (Kuniyuki)
- Fix ipv6 module builds
- Link to v2: https://lore.kernel.org/r/20230613-so-reuseport-v2-0-b7c69a342613@isovalent.com

Changes in v2:
- Correct commit abbrev length (Kuniyuki)
- Reduce duplication (Kuniyuki)
- Add checks on sk_state (Martin)
- Split exporting inet[6]_lookup_reuseport into separate patch (Eric)

---
Daniel Borkmann (1):
      selftests/bpf: Test that SO_REUSEPORT can be used with sk_assign helper

Lorenz Bauer (7):
      udp: re-score reuseport groups when connected sockets are present
      bpf: reject unhashed sockets in bpf_sk_assign
      net: export inet_lookup_reuseport and inet6_lookup_reuseport
      net: remove duplicate reuseport_lookup functions
      net: document inet[6]_lookup_reuseport sk_state requirements
      net: remove duplicate sk_lookup helpers
      bpf, net: Support SO_REUSEPORT sockets with bpf_sk_assign

 include/net/inet6_hashtables.h                     |  81 ++++++++-
 include/net/inet_hashtables.h                      |  74 +++++++-
 include/net/sock.h                                 |   7 +-
 include/uapi/linux/bpf.h                           |   3 -
 net/core/filter.c                                  |   4 +-
 net/ipv4/inet_hashtables.c                         |  68 ++++---
 net/ipv4/udp.c                                     |  88 ++++-----
 net/ipv6/inet6_hashtables.c                        |  71 +++++---
 net/ipv6/udp.c                                     |  98 ++++------
 tools/include/uapi/linux/bpf.h                     |   3 -
 tools/testing/selftests/bpf/network_helpers.c      |   3 +
 .../selftests/bpf/prog_tests/assign_reuse.c        | 197 +++++++++++++++++++++
 .../selftests/bpf/progs/test_assign_reuse.c        | 142 +++++++++++++++
 13 files changed, 660 insertions(+), 179 deletions(-)
---
base-commit: 6f5a630d7c57cd79b1f526a95e757311e32d41e5
change-id: 20230613-so-reuseport-e92c526173ee

Best regards,
-- 
Lorenz Bauer <lmb@isovalent.com>