linux-kernel.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: Florent Revest <revest@chromium.org>
To: bpf@vger.kernel.org
Cc: viro@zeniv.linux.org.uk, davem@davemloft.net, kuba@kernel.org,
	ast@kernel.org, daniel@iogearbox.net, kafai@fb.com, yhs@fb.com,
	andrii@kernel.org, kpsingh@chromium.org, revest@google.com,
	linux-kernel@vger.kernel.org, netdev@vger.kernel.org
Subject: [PATCH bpf-next v4 5/6] bpf: Add an iterator selftest for bpf_sk_storage_get
Date: Wed,  2 Dec 2020 21:55:26 +0100	[thread overview]
Message-ID: <20201202205527.984965-5-revest@google.com> (raw)
In-Reply-To: <20201202205527.984965-1-revest@google.com>

The eBPF program iterates over all files and tasks. For all socket
files, it stores the tgid of the last task it encountered with a handle
to that socket. This is a heuristic for finding the "owner" of a socket
similar to what's done by lsof, ss, netstat or fuser. Potentially, this
information could be used from a cgroup_skb/*gress hook to try to
associate network traffic with processes.

The test makes sure that a socket it created is tagged with prog_tests's
pid.

Signed-off-by: Florent Revest <revest@google.com>
Acked-by: Yonghong Song <yhs@fb.com>
---
 .../selftests/bpf/prog_tests/bpf_iter.c       | 40 +++++++++++++++++++
 .../progs/bpf_iter_bpf_sk_storage_helpers.c   | 24 +++++++++++
 2 files changed, 64 insertions(+)

diff --git a/tools/testing/selftests/bpf/prog_tests/bpf_iter.c b/tools/testing/selftests/bpf/prog_tests/bpf_iter.c
index bb4a638f2e6f..9336d0f18331 100644
--- a/tools/testing/selftests/bpf/prog_tests/bpf_iter.c
+++ b/tools/testing/selftests/bpf/prog_tests/bpf_iter.c
@@ -975,6 +975,44 @@ static void test_bpf_sk_storage_delete(void)
 	bpf_iter_bpf_sk_storage_helpers__destroy(skel);
 }
 
+/* This creates a socket and its local storage. It then runs a task_iter BPF
+ * program that replaces the existing socket local storage with the tgid of the
+ * only task owning a file descriptor to this socket, this process, prog_tests.
+ */
+static void test_bpf_sk_storage_get(void)
+{
+	struct bpf_iter_bpf_sk_storage_helpers *skel;
+	int err, map_fd, val = -1;
+	int sock_fd = -1;
+
+	skel = bpf_iter_bpf_sk_storage_helpers__open_and_load();
+	if (CHECK(!skel, "bpf_iter_bpf_sk_storage_helpers__open_and_load",
+		  "skeleton open_and_load failed\n"))
+		return;
+
+	sock_fd = socket(AF_INET6, SOCK_STREAM, 0);
+	if (CHECK(sock_fd < 0, "socket", "errno: %d\n", errno))
+		goto out;
+
+	map_fd = bpf_map__fd(skel->maps.sk_stg_map);
+
+	err = bpf_map_update_elem(map_fd, &sock_fd, &val, BPF_NOEXIST);
+	if (CHECK(err, "bpf_map_update_elem", "map_update_failed\n"))
+		goto close_socket;
+
+	do_dummy_read(skel->progs.fill_socket_owner);
+
+	err = bpf_map_lookup_elem(map_fd, &sock_fd, &val);
+	CHECK(err || val != getpid(), "bpf_map_lookup_elem",
+	      "map value wasn't set correctly (expected %d, got %d, err=%d)\n",
+	      getpid(), val, err);
+
+close_socket:
+	close(sock_fd);
+out:
+	bpf_iter_bpf_sk_storage_helpers__destroy(skel);
+}
+
 static void test_bpf_sk_storage_map(void)
 {
 	DECLARE_LIBBPF_OPTS(bpf_iter_attach_opts, opts);
@@ -1131,6 +1169,8 @@ void test_bpf_iter(void)
 		test_bpf_sk_storage_map();
 	if (test__start_subtest("bpf_sk_storage_delete"))
 		test_bpf_sk_storage_delete();
+	if (test__start_subtest("bpf_sk_storage_get"))
+		test_bpf_sk_storage_get();
 	if (test__start_subtest("rdonly-buf-out-of-bound"))
 		test_rdonly_buf_out_of_bound();
 	if (test__start_subtest("buf-neg-offset"))
diff --git a/tools/testing/selftests/bpf/progs/bpf_iter_bpf_sk_storage_helpers.c b/tools/testing/selftests/bpf/progs/bpf_iter_bpf_sk_storage_helpers.c
index 01ff3235e413..dde53df37de8 100644
--- a/tools/testing/selftests/bpf/progs/bpf_iter_bpf_sk_storage_helpers.c
+++ b/tools/testing/selftests/bpf/progs/bpf_iter_bpf_sk_storage_helpers.c
@@ -21,3 +21,27 @@ int delete_bpf_sk_storage_map(struct bpf_iter__bpf_sk_storage_map *ctx)
 
 	return 0;
 }
+
+SEC("iter/task_file")
+int fill_socket_owner(struct bpf_iter__task_file *ctx)
+{
+	struct task_struct *task = ctx->task;
+	struct file *file = ctx->file;
+	struct socket *sock;
+	int *sock_tgid;
+
+	if (!task || !file)
+		return 0;
+
+	sock = bpf_sock_from_file(file);
+	if (!sock)
+		return 0;
+
+	sock_tgid = bpf_sk_storage_get(&sk_stg_map, sock->sk, 0, 0);
+	if (!sock_tgid)
+		return 0;
+
+	*sock_tgid = task->tgid;
+
+	return 0;
+}
-- 
2.29.2.454.gaff20da3a2-goog


  parent reply	other threads:[~2020-12-02 20:57 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-12-02 20:55 [PATCH bpf-next v4 1/6] net: Remove the err argument from sock_from_file Florent Revest
2020-12-02 20:55 ` [PATCH bpf-next v4 2/6] bpf: Add a bpf_sock_from_file helper Florent Revest
2020-12-02 20:55 ` [PATCH bpf-next v4 3/6] bpf: Expose bpf_sk_storage_* to iterator programs Florent Revest
2020-12-02 20:55 ` [PATCH bpf-next v4 4/6] bpf: Add an iterator selftest for bpf_sk_storage_delete Florent Revest
2020-12-02 20:55 ` Florent Revest [this message]
2020-12-04  1:39   ` [PATCH bpf-next v4 5/6] bpf: Add an iterator selftest for bpf_sk_storage_get Martin KaFai Lau
2020-12-02 20:55 ` [PATCH bpf-next v4 6/6] bpf: Test bpf_sk_storage_get in tcp iterators Florent Revest
2020-12-04  2:05   ` Martin KaFai Lau
2020-12-04 11:37     ` Florent Revest

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20201202205527.984965-5-revest@google.com \
    --to=revest@chromium.org \
    --cc=andrii@kernel.org \
    --cc=ast@kernel.org \
    --cc=bpf@vger.kernel.org \
    --cc=daniel@iogearbox.net \
    --cc=davem@davemloft.net \
    --cc=kafai@fb.com \
    --cc=kpsingh@chromium.org \
    --cc=kuba@kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=netdev@vger.kernel.org \
    --cc=revest@google.com \
    --cc=viro@zeniv.linux.org.uk \
    --cc=yhs@fb.com \
    --subject='Re: [PATCH bpf-next v4 5/6] bpf: Add an iterator selftest for bpf_sk_storage_get' \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).