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From: Lorenz Bauer <lmb@cloudflare.com>
To: kafai@fb.com, Shuah Khan <shuah@kernel.org>,
	Alexei Starovoitov <ast@kernel.org>,
	Daniel Borkmann <daniel@iogearbox.net>
Cc: kernel-team@cloudflare.com, Lorenz Bauer <lmb@cloudflare.com>,
	linux-kselftest@vger.kernel.org, netdev@vger.kernel.org,
	bpf@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH bpf-next v2 4/4] selftest: bpf: Test copying a sockmap and sockhash
Date: Mon, 28 Sep 2020 10:08:05 +0100	[thread overview]
Message-ID: <20200928090805.23343-5-lmb@cloudflare.com> (raw)
In-Reply-To: <20200928090805.23343-1-lmb@cloudflare.com>

Since we can now call map_update_elem(sockmap) from bpf_iter context
it's possible to copy a sockmap or sockhash in the kernel. Add a
selftest which exercises this.

Signed-off-by: Lorenz Bauer <lmb@cloudflare.com>
---
 .../selftests/bpf/prog_tests/sockmap_basic.c  | 14 +++++-----
 .../selftests/bpf/progs/bpf_iter_sockmap.c    | 27 +++++++++++++++----
 2 files changed, 30 insertions(+), 11 deletions(-)

diff --git a/tools/testing/selftests/bpf/prog_tests/sockmap_basic.c b/tools/testing/selftests/bpf/prog_tests/sockmap_basic.c
index e8a4bfb4d9f4..854a508e81ce 100644
--- a/tools/testing/selftests/bpf/prog_tests/sockmap_basic.c
+++ b/tools/testing/selftests/bpf/prog_tests/sockmap_basic.c
@@ -194,7 +194,7 @@ static void test_sockmap_invalid_update(void)
 		test_sockmap_invalid_update__destroy(skel);
 }
 
-static void test_sockmap_iter(enum bpf_map_type map_type)
+static void test_sockmap_copy(enum bpf_map_type map_type)
 {
 	DECLARE_LIBBPF_OPTS(bpf_iter_attach_opts, opts);
 	int err, len, src_fd, iter_fd, duration = 0;
@@ -242,7 +242,7 @@ static void test_sockmap_iter(enum bpf_map_type map_type)
 	linfo.map.map_fd = src_fd;
 	opts.link_info = &linfo;
 	opts.link_info_len = sizeof(linfo);
-	link = bpf_program__attach_iter(skel->progs.count_elems, &opts);
+	link = bpf_program__attach_iter(skel->progs.copy, &opts);
 	if (CHECK(IS_ERR(link), "attach_iter", "attach_iter failed\n"))
 		goto out;
 
@@ -265,6 +265,8 @@ static void test_sockmap_iter(enum bpf_map_type map_type)
 		  skel->bss->socks, num_sockets))
 		goto close_iter;
 
+	compare_cookies(src, skel->maps.dst);
+
 close_iter:
 	close(iter_fd);
 free_link:
@@ -294,8 +296,8 @@ void test_sockmap_basic(void)
 		test_sockmap_update(BPF_MAP_TYPE_SOCKHASH);
 	if (test__start_subtest("sockmap update in unsafe context"))
 		test_sockmap_invalid_update();
-	if (test__start_subtest("sockmap iter"))
-		test_sockmap_iter(BPF_MAP_TYPE_SOCKMAP);
-	if (test__start_subtest("sockhash iter"))
-		test_sockmap_iter(BPF_MAP_TYPE_SOCKHASH);
+	if (test__start_subtest("sockmap copy"))
+		test_sockmap_copy(BPF_MAP_TYPE_SOCKMAP);
+	if (test__start_subtest("sockhash copy"))
+		test_sockmap_copy(BPF_MAP_TYPE_SOCKHASH);
 }
diff --git a/tools/testing/selftests/bpf/progs/bpf_iter_sockmap.c b/tools/testing/selftests/bpf/progs/bpf_iter_sockmap.c
index 1af7555f6057..f3af0e30cead 100644
--- a/tools/testing/selftests/bpf/progs/bpf_iter_sockmap.c
+++ b/tools/testing/selftests/bpf/progs/bpf_iter_sockmap.c
@@ -22,21 +22,38 @@ struct {
 	__type(value, __u64);
 } sockhash SEC(".maps");
 
+struct {
+	__uint(type, BPF_MAP_TYPE_SOCKHASH);
+	__uint(max_entries, 64);
+	__type(key, __u32);
+	__type(value, __u64);
+} dst SEC(".maps");
+
 __u32 elems = 0;
 __u32 socks = 0;
 
 SEC("iter/sockmap")
-int count_elems(struct bpf_iter__sockmap *ctx)
+int copy(struct bpf_iter__sockmap *ctx)
 {
 	struct sock *sk = ctx->sk;
 	__u32 tmp, *key = ctx->key;
 	int ret;
 
-	if (key)
-		elems++;
+	if (!key)
+		return 0;
 
-	if (sk)
+	elems++;
+
+	/* We need a temporary buffer on the stack, since the verifier doesn't
+	 * let us use the pointer from the context as an argument to the helper.
+	 */
+	tmp = *key;
+
+	if (sk) {
 		socks++;
+		return bpf_map_update_elem(&dst, &tmp, sk, 0) != 0;
+	}
 
-	return 0;
+	ret = bpf_map_delete_elem(&dst, &tmp);
+	return ret && ret != -ENOENT;
 }
-- 
2.25.1


  parent reply	other threads:[~2020-09-28  9:08 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <20200928090805.23343-1-lmb@cloudflare.com>
2020-09-28  9:08 ` [PATCH bpf-next v2 1/4] bpf: sockmap: enable map_update_elem from bpf_iter Lorenz Bauer
2020-09-29  5:35   ` Martin KaFai Lau
2020-09-28  9:08 ` [PATCH bpf-next v2 2/4] selftests: bpf: Add helper to compare socket cookies Lorenz Bauer
2020-09-29  5:59   ` Martin KaFai Lau
2020-09-29 15:48     ` Alexei Starovoitov
2020-09-30  9:28       ` Lorenz Bauer
2020-10-01  7:23         ` Alexei Starovoitov
2020-10-01 17:09           ` Andrii Nakryiko
2020-10-01 17:11             ` Alexei Starovoitov
2020-10-02 10:08               ` Lorenz Bauer
2020-09-28  9:08 ` [PATCH bpf-next v2 3/4] selftests: bpf: remove shared header from sockmap iter test Lorenz Bauer
2020-09-28  9:08 ` Lorenz Bauer [this message]
2020-09-29  6:06   ` [PATCH bpf-next v2 4/4] selftest: bpf: Test copying a sockmap and sockhash Martin KaFai Lau
2020-09-29  9:21     ` Lorenz Bauer
2020-09-29 17:23       ` Martin KaFai Lau
2020-09-30  9:37         ` Lorenz Bauer

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