Subject: [PATCH bpf-next 0/3] bpf: support cloning sk storage on accept()

From: Stanislav Fomichev <[email-masked]>
Date: Wed, 7 Aug 2019 08:47:17 -0700

Currently there is no way to propagate sk storage from the listener
socket to a newly accepted one. Consider the following use case:

        fd = socket();
        setsockopt(fd, SOL_IP, IP_TOS,...);
        /* ^^^ setsockopt BPF program triggers here and saves something
         * into sk storage of the listener.
         */
        listen(fd, ...);
        while (client = accept(fd)) {
                /* At this point all association between listener
                 * socket and newly accepted one is gone. New
                 * socket will not have any sk storage attached.
                 */
        }

Let's add new BPF_SK_STORAGE_GET_F_CLONE flag that can be passed to
bpf_sk_storage_get. This new flag indicates that that particular
bpf_sk_storage_elem should be cloned when the socket is cloned.

Cc: Martin KaFai Lau <[email-masked]>

Stanislav Fomichev (3):
  bpf: support cloning sk storage on accept()
  bpf: sync bpf.h to tools/
  selftests/bpf: add sockopt clone/inheritance test

 include/net/bpf_sk_storage.h                  |  10 +
 include/uapi/linux/bpf.h                      |   1 +
 net/core/bpf_sk_storage.c                     | 102 ++++++-
 net/core/sock.c                               |   9 +-
 tools/include/uapi/linux/bpf.h                |   1 +
 tools/testing/selftests/bpf/.gitignore        |   1 +
 tools/testing/selftests/bpf/Makefile          |   3 +-
 .../selftests/bpf/progs/sockopt_inherit.c     | 102 +++++++
 .../selftests/bpf/test_sockopt_inherit.c      | 252 ++++++++++++++++++
 9 files changed, 473 insertions(+), 8 deletions(-)
 create mode 100644 tools/testing/selftests/bpf/progs/sockopt_inherit.c
 create mode 100644 tools/testing/selftests/bpf/test_sockopt_inherit.c

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2.22.0.770.g0f2c4a37fd-goog