From patchwork Thu Dec 1 15:13:52 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Maryam Tahhan X-Patchwork-Id: 13061419 X-Patchwork-Delegate: bpf@iogearbox.net Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 4AB76C43217 for ; Thu, 1 Dec 2022 15:15:00 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230480AbiLAPO7 (ORCPT ); Thu, 1 Dec 2022 10:14:59 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51990 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231164AbiLAPO5 (ORCPT ); Thu, 1 Dec 2022 10:14:57 -0500 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A3E469953F for ; Thu, 1 Dec 2022 07:13:59 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1669907638; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding; bh=9BZSv1KMusXSU2SW8G1TuRVioFf+tWfm0VsCOs0TpbI=; b=Ma7pj8eakTLJxWMe0C+B6alGAFNVDiCaTuqZaAKkPsyK6/QjDdVk1EKsUulsMAHrNlRyu7 r1c7X7JdFh1kshcVHAx1CNdk1VV/zX011ZZy5jMnfRb3zYBd+eDBY/2Oi5PQdKlPn6DRer l9QaEtWziI/L6Om08AaI8ce4Sdje6F0= Received: from mail-wm1-f70.google.com (mail-wm1-f70.google.com [209.85.128.70]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_128_GCM_SHA256) id us-mta-614-Hkg2D9FYPsaNvM2MJ5BwCw-1; Thu, 01 Dec 2022 10:13:57 -0500 X-MC-Unique: Hkg2D9FYPsaNvM2MJ5BwCw-1 Received: by mail-wm1-f70.google.com with SMTP id ay40-20020a05600c1e2800b003cf8aa16377so968447wmb.7 for ; Thu, 01 Dec 2022 07:13:57 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=9BZSv1KMusXSU2SW8G1TuRVioFf+tWfm0VsCOs0TpbI=; b=YASOw9NjlZV4le4n44Dprc+SL7ETCSaWNnx0rTEjmKBa9fM2JJVpKkj5W4akFm38Sd gXUIRWQ8MGytGPORB0UuszNJXCEKVeDvucDg1BoW/Arb2lo6Y+fZFdE8jrLgrcUtA4Y4 oLow6k2CVU8S5ooSYIMAEKOPzZLBdIYtI648oDdxkpu89aLPFqR/uHHZA5HfFglRWQkR GigNK6gniOPBUBWedfrFEruEezb0ZTWQMvIuPvuBMWgZEG2eACXFCQGwF7eRwSrD6fPL sDVHf9EMY2dwC5iYpU4QmUF1LN8ir2Dwu80BHcxThEonjT66RYKERIQlC+0aF3NUm972 zRPw== X-Gm-Message-State: ANoB5pmZW4RHrTjroUK72TE8T9W14WolPwKr8sboozDavrLt9vSpa4An ZWDGbf0d3WUdgvj7FW63y9lruLF9jBd48K5ofyRPBkOnvAps+X28c4JRpMIaY9Y2iVLlDGiiloC sruLIL4c5vANAtEdhuSLF8IXKQ//FxmdtuFR1kIv/DBZJXzyCG3y3ydXrctEhsPw= X-Received: by 2002:adf:f30e:0:b0:242:1ef4:fb8a with SMTP id i14-20020adff30e000000b002421ef4fb8amr9582906wro.146.1669907635790; Thu, 01 Dec 2022 07:13:55 -0800 (PST) X-Google-Smtp-Source: AA0mqf7aqi+sx0a1BlhbFWt88m++k69JXVHVENej8qjLVFVq7brBxpfGQEC8kSHzKIk/GG+juhS+JQ== X-Received: by 2002:adf:f30e:0:b0:242:1ef4:fb8a with SMTP id i14-20020adff30e000000b002421ef4fb8amr9582862wro.146.1669907635184; Thu, 01 Dec 2022 07:13:55 -0800 (PST) Received: from localhost.localdomain ([78.16.131.111]) by smtp.gmail.com with ESMTPSA id l7-20020a5d4107000000b00242246c2f7csm4788559wrp.101.2022.12.01.07.13.54 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 01 Dec 2022 07:13:54 -0800 (PST) From: mtahhan@redhat.com To: bpf@vger.kernel.org, linux-doc@vger.kernel.org Cc: jbrouer@redhat.com, thoiland@redhat.com, donhunte@redhat.com, john.fastabend@gmail.com, Maryam Tahhan Subject: [PATCH bpf-next v2 1/1] docs: BPF_MAP_TYPE_SOCK[MAP|HASH] Date: Thu, 1 Dec 2022 15:13:52 +0000 Message-Id: <20221201151352.34810-1-mtahhan@redhat.com> X-Mailer: git-send-email 2.34.1 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org X-Patchwork-Delegate: bpf@iogearbox.net From: Maryam Tahhan Add documentation for BPF_MAP_TYPE_SOCK[MAP|HASH] including kernel versions introduced, usage and examples. Signed-off-by: Maryam Tahhan Acked-by: John Fastabend --- v2: - Fixed typos and user space references to BPF helpers. - Added update, lookup and delete BPF helpers. --- --- Documentation/bpf/map_sockmap.rst | 482 ++++++++++++++++++++++++++++++ 1 file changed, 482 insertions(+) create mode 100644 Documentation/bpf/map_sockmap.rst diff --git a/Documentation/bpf/map_sockmap.rst b/Documentation/bpf/map_sockmap.rst new file mode 100644 index 000000000000..398a01e863ff --- /dev/null +++ b/Documentation/bpf/map_sockmap.rst @@ -0,0 +1,482 @@ +.. SPDX-License-Identifier: GPL-2.0-only +.. Copyright Red Hat + +============================================== +BPF_MAP_TYPE_SOCKMAP and BPF_MAP_TYPE_SOCKHASH +============================================== + +.. note:: + - ``BPF_MAP_TYPE_SOCKMAP`` was introduced in kernel version 4.14 + - ``BPF_MAP_TYPE_SOCKHASH`` was introduced in kernel version 4.18 + +``BPF_MAP_TYPE_SOCKMAP`` is backed by an array that uses an integer key as the +index to lookup a reference to a sock struct. The map values are sockets. +Similarly, ``BPF_MAP_TYPE_SOCKHASH`` is a hash backed BPF map that holds +references to sockets. + +.. note:: + - The value type must be __u32 or __u64. + - The value type of __u64 is to support socket cookies. + +When these maps are created BPF programs are attached to them. The list of +allowed programs is shown below: + +.. code-block:: c + + struct sk_psock_progs { + struct bpf_prog *msg_parser; + struct bpf_prog *stream_parser; + struct bpf_prog *stream_verdict; + struct bpf_prog *skb_verdict; + }; + +.. note:: + Users are not allowed to attach ``stream_verdict`` and ``skb_verdict`` + programs to the same map. + +The parser programs determine how much data needs to be queued to come to a +verdict. The verdict programs return a verdict ``__SK_DROP``, ``__SK_PASS``, or +``__SK_REDIRECT``. + +The attach types for the map programs are: + +- ``msg_parser`` program - ``BPF_SK_MSG_VERDICT``. +- ``stream_parser`` program - ``BPF_SK_SKB_STREAM_PARSER``. +- ``stream_verdict`` program - ``BPF_SK_SKB_STREAM_VERDICT``. +- ``skb_verdict`` program - ``BPF_SK_SKB_VERDICT``. + +These maps can be used to redirect skbs between sockets or to apply policy at +the socket level based on the result of a verdict program with the help of the +BPF helpers ``bpf_sk_redirect_map()``, ``bpf_sk_redirect_hash()``, +``bpf_msg_redirect_map()`` and ``bpf_msg_redirect_hash()``. + +When a socket is inserted into one of these maps, its socket callbacks are +replaced and a ``struct sk_psock`` is attached to it. Additionally, this +``sk_psock`` inherits the programs that are attached to the map. + +.. note:: + For more details of the socket callbacks that get replaced please see: + + - TCP BPF functions: ``net/ipv4/tcp_bpf.c`` + - UDP BPF functions: ``net/ipv4/udp_bpf.c`` + +There are additional helpers available to use with the parser and verdict +programs: ``bpf_msg_apply_bytes()`` and ``bpf_msg_cork_bytes()``. With +``bpf_msg_apply_bytes()`` BPF programs can tell the infrastructure how many +bytes the given verdict should apply to. The helper ``bpf_msg_cork_bytes()`` +handles a different case where a BPF program can not reach a verdict on a msg +until it receives more bytes AND the program doesn't want to forward the packet +until it is known to be good. + +Finally, the helpers ``bpf_msg_pull_data()`` and ``bpf_msg_push_data()`` are +available to ``BPF_PROG_TYPE_SK_MSG`` BPF programs to pull in data and set the +start and end pointer to given values or to add metadata to the ``struct +sk_msg_buff *msg``. + +Usage +===== +Kernel BPF +---------- +bpf_msg_redirect_map() +^^^^^^^^^^^^^^^^^^^^^^ +.. code-block:: c + + long bpf_msg_redirect_map(struct sk_msg_buff *msg, struct bpf_map *map, u32 key, u64 flags) + +This helper is used in programs implementing policies at the socket level. If +the message ``msg`` is allowed to pass (i.e. if the verdict BPF program +returns ``SK_PASS``), redirect it to the socket referenced by ``map`` (of type +``BPF_MAP_TYPE_SOCKMAP``) at index ``key``. Both ingress and egress interfaces +can be used for redirection. The ``BPF_F_INGRESS`` value in ``flags`` is used +to select the ingress path otherwise the egress path is selected. This is the +only flag supported for now. + +Returns ``SK_PASS`` on success, or ``SK_DROP`` on error. + +bpf_sk_redirect_map() +^^^^^^^^^^^^^^^^^^^^^ +.. code-block:: c + + long bpf_sk_redirect_map(struct sk_buff *skb, struct bpf_map *map, u32 key u64 flags) + +Redirect the packet to the socket referenced by ``map`` (of type +``BPF_MAP_TYPE_SOCKMAP``) at index ``key``. Both ingress and egress interfaces +can be used for redirection. The ``BPF_F_INGRESS`` value in ``flags`` is used +to select the ingress path otherwise the egress path is selected. This is the +only flag supported for now. + +Returns ``SK_PASS`` on success, or ``SK_DROP`` on error. + +bpf_map_lookup_elem() +^^^^^^^^^^^^^^^^^^^^^ +.. code-block:: c + + void *bpf_map_lookup_elem(struct bpf_map *map, const void *key) + +socket entries of type ``struct sock *`` can be retrieved using the +``bpf_map_lookup_elem()`` helper. + +bpf_sock_map_update() +^^^^^^^^^^^^^^^^^^^^^ +.. code-block:: c + + long bpf_sock_map_update(struct bpf_sock_ops *skops, struct bpf_map *map, void *key, u64 flags) + +Add an entry to, or update a ``map`` referencing sockets. The ``skops`` is used +as a new value for the entry associated to ``key``. The ``flags`` argument can +be one of the following: + +- ``BPF_ANY``: Create a new element or update an existing element. +- ``BPF_NOEXIST``: Create a new element only if it did not exist. +- ``BPF_EXIST``: Update an existing element. + +If the ``map`` has BPF programs (parser and verdict), those will be inherited +by the socket being added. If the socket is already attached to BPF programs, +this results in an error. + +Returns 0 on success, or a negative error in case of failure. + +bpf_sock_hash_update() +^^^^^^^^^^^^^^^^^^^^^^ +.. code-block:: c + + long bpf_sock_hash_update(struct bpf_sock_ops *skops, struct bpf_map *map, void *key, u64 flags) + +Add an entry to, or update a sockhash ``map`` referencing sockets. The ``skops`` +is used as a new value for the entry associated to ``key``. + +The ``flags`` argument can be one of the following: + +- ``BPF_ANY``: Create a new element or update an existing element. +- ``BPF_NOEXIST``: Create a new element only if it did not exist. +- ``BPF_EXIST``: Update an existing element. + +If the ``map`` has BPF programs (parser and verdict), those will be inherited +by the socket being added. If the socket is already attached to BPF programs, +this results in an error. + +Returns 0 on success, or a negative error in case of failure. + +bpf_msg_redirect_hash() +^^^^^^^^^^^^^^^^^^^^^^^ +.. code-block:: c + + long bpf_msg_redirect_hash(struct sk_msg_buff *msg, struct bpf_map *map, void *key, u64 flags) + +This helper is used in programs implementing policies at the socket level. If +the message ``msg`` is allowed to pass (i.e. if the verdict BPF program returns +``SK_PASS``), redirect it to the socket referenced by ``map`` (of type +``BPF_MAP_TYPE_SOCKHASH``) using hash ``key``. Both ingress and egress +interfaces can be used for redirection. The ``BPF_F_INGRESS`` value in +``flags`` is used to select the ingress path otherwise the egress path is +selected. This is the only flag supported for now. + +Returns ``SK_PASS`` on success, or ``SK_DROP`` on error. + +bpf_sk_redirect_hash() +^^^^^^^^^^^^^^^^^^^^^^ +.. code-block:: c + + long bpf_sk_redirect_hash(struct sk_buff *skb, struct bpf_map *map, void *key, u64 flags) + +This helper is used in programs implementing policies at the skb socket level. +If the sk_buff ``skb`` is allowed to pass (i.e. if the verdict BPF program +returns ``SK_PASS``), redirect it to the socket referenced by ``map`` (of type +``BPF_MAP_TYPE_SOCKHASH``) using hash ``key``. Both ingress and egress +interfaces can be used for redirection. The ``BPF_F_INGRESS`` value in +``flags`` is used to select the ingress path otherwise the egress path is +selected. This is the only flag supported for now. + +Returns ``SK_PASS`` on success, or ``SK_DROP`` on error. + +bpf_msg_apply_bytes() +^^^^^^^^^^^^^^^^^^^^^^ +.. code-block:: c + + long bpf_msg_apply_bytes(struct sk_msg_buff *msg, u32 bytes) + +For socket policies, apply the verdict of the BPF program to the next (number +of ``bytes``) of message ``msg``. For example, this helper can be used in the +following cases: + +- A single ``sendmsg()`` or ``sendfile()`` system call contains multiple + logical messages that the BPF program is supposed to read and for which it + should apply a verdict. +- A BPF program only cares to read the first ``bytes`` of a ``msg``. If the + message has a large payload, then setting up and calling the BPF program + repeatedly for all bytes, even though the verdict is already known, would + create unnecessary overhead. + +Returns 0 + +bpf_msg_cork_bytes() +^^^^^^^^^^^^^^^^^^^^^^ +.. code-block:: c + + long bpf_msg_cork_bytes(struct sk_msg_buff *msg, u32 bytes) + +For socket policies, prevent the execution of the verdict BPF program for +message ``msg`` until the number of ``bytes`` have been accumulated. + +This can be used when one needs a specific number of bytes before a verdict can +be assigned, even if the data spans multiple ``sendmsg()`` or ``sendfile()`` +calls. + +Returns 0 + +bpf_msg_pull_data() +^^^^^^^^^^^^^^^^^^^^^^ +.. code-block:: c + + long bpf_msg_pull_data(struct sk_msg_buff *msg, u32 start, u32 end, u64 flags) + +For socket policies, pull in non-linear data from user space for ``msg`` and set +pointers ``msg->data`` and ``msg->data_end`` to ``start`` and ``end`` bytes +offsets into ``msg``, respectively. + +If a program of type ``BPF_PROG_TYPE_SK_MSG`` is run on a ``msg`` it can only +parse data that the (``data``, ``data_end``) pointers have already consumed. +For ``sendmsg()`` hooks this is likely the first scatterlist element. But for +calls relying on the ``sendpage`` handler (e.g. ``sendfile()``) this will be +the range (**0**, **0**) because the data is shared with user space and by +default the objective is to avoid allowing user space to modify data while (or +after) BPF verdict is being decided. This helper can be used to pull in data +and to set the start and end pointer to given values. Data will be copied if +necessary (i.e. if data was not linear and if start and end pointers do not +point to the same chunk). + +A call to this helper is susceptible to change the underlying packet buffer. +Therefore, at load time, all checks on pointers previously done by the verifier +are invalidated and must be performed again, if the helper is used in +combination with direct packet access. + +All values for ``flags`` are reserved for future usage, and must be left at +zero. + +Returns 0 on success, or a negative error in case of failure. + +bpf_map_lookup_elem() +^^^^^^^^^^^^^^^^^^^^^ + +.. code-block:: c + + void *bpf_map_lookup_elem(struct bpf_map *map, const void *key) + +Lookup a socket entry in the sockmap or sockhash map. + +Returns the socket entry associated to ``key``, or NULL if no entry was found. + +bpf_map_update_elem() +^^^^^^^^^^^^^^^^^^^^^ +.. code-block:: c + + long bpf_map_update_elem(struct bpf_map *map, const void *key, const void *value, u64 flags) + +Add or update a socket entry in a sockmap or sockhash. + +The flags argument can be one of the following: + +- BPF_ANY: Create a new element or update an existing element. +- BPF_NOEXIST: Create a new element only if it did not exist. +- BPF_EXIST: Update an existing element. + +Returns 0 on success, or a negative error in case of failure. + +bpf_map_delete_elem() +^^^^^^^^^^^^^^^^^^^^^^ +.. code-block:: c + + long bpf_map_delete_elem(struct bpf_map *map, const void *key) + +Delete a socket entry from a sockmap or a sockhash. + +Returns 0 on success, or a negative error in case of failure. + +User space +---------- +bpf_map_update_elem() +^^^^^^^^^^^^^^^^^^^^^ +.. code-block:: c + + int bpf_map_update_elem(int fd, const void *key, const void *value, __u64 flags) + +Sockmap entries can be added or updated using the ``bpf_map_update_elem()`` +function. The ``key`` parameter is the index value of the sockmap array. And the +``value`` parameter is the FD value of that socket. + +Under the hood, the sockmap update function uses the socket FD value to +retrieve the associated socket and its attached psock. + +The flags argument can be one of the following: + +- BPF_ANY: Create a new element or update an existing element. +- BPF_NOEXIST: Create a new element only if it did not exist. +- BPF_EXIST: Update an existing element. + +bpf_map_lookup_elem() +^^^^^^^^^^^^^^^^^^^^^ +.. code-block:: c + + int bpf_map_lookup_elem(int fd, const void *key, void *value) + +Sockmap entries can be retrieved using the ``bpf_map_lookup_elem()`` function. + +.. note:: + The entry returned is a socket cookie rather than a socket itself. + +bpf_map_delete_elem() +^^^^^^^^^^^^^^^^^^^^^ +.. code-block:: c + + int bpf_map_delete_elem(int fd, const void *key) + +Sockmap entries can be deleted using the ``bpf_map_delete_elem()`` +function. + +Returns 0 on success, or negative error in case of failure. + +Examples +======== + +Kernel BPF +---------- +Several examples of the use of sockmap APIs can be found in: + +- `tools/testing/selftests/bpf/progs/test_sockmap_kern.h`_ +- `tools/testing/selftests/bpf/progs/sockmap_parse_prog.c`_ +- `tools/testing/selftests/bpf/progs/sockmap_verdict_prog.c`_ +- `tools/testing/selftests/bpf/progs/test_sockmap_listen.c`_ +- `tools/testing/selftests/bpf/progs/test_sockmap_update.c`_ + +The following code snippet shows how to declare a sockmap. + +.. code-block:: c + + struct { + __uint(type, BPF_MAP_TYPE_SOCKMAP); + __uint(max_entries, 1); + __type(key, __u32); + __type(value, __u64); + } sock_map_rx SEC(".maps"); + +The following code snippet shows a sample parser program. + +.. code-block:: c + + SEC("sk_skb/stream_parser") + int bpf_prog_parser(struct __sk_buff *skb) + { + return skb->len; + } + +The following code snippet shows a simple verdict program that interacts with a +sockmap to redirect traffic to another socket based on the local port. + +.. code-block:: c + + SEC("sk_skb/stream_verdict") + int bpf_prog_verdict(struct __sk_buff *skb) + { + __u32 lport = skb->local_port; + __u32 idx = 0; + + if (lport == 10000) + return bpf_sk_redirect_map(skb, &sock_map_rx, idx, 0); + + return SK_PASS; + } + +The following code snippet shows how to declare a sockhash map. + +.. code-block:: c + + struct socket_key { + __u32 src_ip; + __u32 dst_ip; + __u32 src_port; + __u32 dst_port; + }; + + struct { + __uint(type, BPF_MAP_TYPE_SOCKHASH); + __uint(max_entries, 1); + __type(key, struct socket_key); + __type(value, __u64); + } sock_hash_rx SEC(".maps"); + +The following code snippet shows a simple verdict program that interacts with a +sockhash to redirect traffic to another socket based on a hash of some of the +skb parameters. + +.. code-block:: c + + static inline + void extract_socket_key(struct __sk_buff *skb, struct socket_key *key) + { + key->src_ip = skb->remote_ip4; + key->dst_ip = skb->local_ip4; + key->src_port = skb->remote_port >> 16; + key->dst_port = (bpf_htonl(skb->local_port)) >> 16; + } + + SEC("sk_skb/stream_verdict") + int bpf_prog_verdict(struct __sk_buff *skb) + { + struct socket_key key; + + extract_socket_key(skb, &key); + + return bpf_sk_redirect_hash(skb, &sock_hash_rx, &key, 0); + } + +User space +---------- +Several examples of the use of sockmap APIs can be found in: + +- `tools/testing/selftests/bpf/prog_tests/sockmap_basic.c`_ +- `tools/testing/selftests/bpf/test_sockmap.c`_ +- `tools/testing/selftests/bpf/test_maps.c`_ + +The following code snippet shows how to create a sockmap and add a socket +entry: + +.. code-block:: c + + /* Create a map and populate it with one socket*/ + static void create_sample_sockmap(int s) + { + const int index = 0; + int map, err; + + map = bpf_map_create(BPF_MAP_TYPE_SOCKMAP, NULL, sizeof(int), sizeof(int), 1, NULL); + if (map < 0) { + fprintf(stderr, "Failed to create sockmap: %s\n", strerror(errno)); + goto out; + } + + err = bpf_map_update_elem(map, &index, &s, BPF_NOEXIST); + if (err) { + fprintf(stderr, "Failed to update sockmap: %s\n", strerror(errno)); + goto out; + } + + out: + close(map); + } + +References +=========== + +- https://github.com/jrfastab/linux-kernel-xdp/commit/c89fd73cb9d2d7f3c716c3e00836f07b1aeb261f +- https://lwn.net/Articles/731133/ +- http://vger.kernel.org/lpc_net2018_talks/ktls_bpf_paper.pdf +- https://lwn.net/Articles/748628/ + +.. _`tools/testing/selftests/bpf/progs/test_sockmap_kern.h`: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/tools/testing/selftests/bpf/progs/test_sockmap_kern.h +.. _`tools/testing/selftests/bpf/progs/sockmap_parse_prog.c`: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/tools/testing/selftests/bpf/progs/sockmap_parse_prog.c +.. _`tools/testing/selftests/bpf/progs/sockmap_verdict_prog.c`: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/tools/testing/selftests/bpf/progs/sockmap_verdict_prog.c +.. _`tools/testing/selftests/bpf/prog_tests/sockmap_basic.c`: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/tools/testing/selftests/bpf/prog_tests/sockmap_basic.c +.. _`tools/testing/selftests/bpf/test_sockmap.c`: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/tools/testing/selftests/bpf/test_sockmap.c +.. _`tools/testing/selftests/bpf/test_maps.c`: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/tools/testing/selftests/bpf/test_maps.c +.. _`tools/testing/selftests/bpf/progs/test_sockmap_listen.c`: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/tools/testing/selftests/bpf/progs/test_sockmap_listen.c +.. _`tools/testing/selftests/bpf/progs/test_sockmap_update.c`: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/tools/testing/selftests/bpf/progs/test_sockmap_update.c