Commit 5b87adc3 authored by Lorenz Bauer's avatar Lorenz Bauer Committed by Alexei Starovoitov
Browse files

selftest: bpf: Test copying a sockmap and sockhash 



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: default avatarLorenz Bauer <lmb@cloudflare.com>
Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200928090805.23343-5-lmb@cloudflare.com
parent 27870317

tools/testing/selftests/bpf/prog_tests/sockmap_basic.c

+8 −6
Original line number Diff line number Diff line
@@ -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);

}

tools/testing/selftests/bpf/progs/bpf_iter_sockmap.c

+22 −5
Original line number Diff line number Diff line
@@ -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)

	if (!key)

		return 0;



	elems++;



	if (sk)

	/* 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;

}