selftests/bpf: add cgroup_skb netns cookie tests

JIRA: https://issues.redhat.com/browse/RHEL-110279

commit 9138048
Author: Mahe Tardy <mahe.tardy@gmail.com>
Date:   Tue Feb 25 12:50:31 2025 +0000

    selftests/bpf: add cgroup_skb netns cookie tests

    Add netns cookie test that verifies the helper is now supported and work
    in the context of cgroup_skb programs.

    Signed-off-by: Mahe Tardy <mahe.tardy@gmail.com>
    Link: https://lore.kernel.org/r/20250225125031.258740-2-mahe.tardy@gmail.com
    Signed-off-by: Alexei Starovoitov <ast@kernel.org>

Signed-off-by: Jerome Marchand <jmarchan@redhat.com>

Author: jeromemarchand

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

@@ -33,20 +33,25 @@ void test_netns_cookie(void)
 
 	skel->links.get_netns_cookie_sockops = bpf_program__attach_cgroup(
 		skel->progs.get_netns_cookie_sockops, cgroup_fd);
-	if (!ASSERT_OK_PTR(skel->links.get_netns_cookie_sockops, "prog_attach"))
+	if (!ASSERT_OK_PTR(skel->links.get_netns_cookie_sockops, "prog_attach_sockops"))
 		goto done;
 
 	verdict = bpf_program__fd(skel->progs.get_netns_cookie_sk_msg);
 	map = bpf_map__fd(skel->maps.sock_map);
 	err = bpf_prog_attach(verdict, map, BPF_SK_MSG_VERDICT, 0);
-	if (!ASSERT_OK(err, "prog_attach"))
+	if (!ASSERT_OK(err, "prog_attach_sk_msg"))
 		goto done;
 
 	tc_fd = bpf_program__fd(skel->progs.get_netns_cookie_tcx);
 	err = bpf_prog_attach_opts(tc_fd, loopback, BPF_TCX_INGRESS, &opta);
-	if (!ASSERT_OK(err, "prog_attach"))
+	if (!ASSERT_OK(err, "prog_attach_tcx"))
 		goto done;
 
+	skel->links.get_netns_cookie_cgroup_skb = bpf_program__attach_cgroup(
+		skel->progs.get_netns_cookie_cgroup_skb, cgroup_fd);
+	if (!ASSERT_OK_PTR(skel->links.get_netns_cookie_cgroup_skb, "prog_attach_cgroup_skb"))
+		goto cleanup_tc;
+
 	server_fd = start_server(AF_INET6, SOCK_STREAM, "::1", 0, 0);
 	if (CHECK(server_fd < 0, "start_server", "errno %d\n", errno))
 		goto cleanup_tc;
@@ -69,16 +74,18 @@ void test_netns_cookie(void)
 	if (!ASSERT_OK(err, "getsockopt"))
 		goto cleanup_tc;
 
-	ASSERT_EQ(val, cookie_expected_value, "cookie_value");
+	ASSERT_EQ(val, cookie_expected_value, "cookie_value_sockops");
 
 	err = bpf_map_lookup_elem(bpf_map__fd(skel->maps.sk_msg_netns_cookies),
 				  &client_fd, &val);
 	if (!ASSERT_OK(err, "map_lookup(sk_msg_netns_cookies)"))
 		goto cleanup_tc;
 
-	ASSERT_EQ(val, cookie_expected_value, "cookie_value");
-	ASSERT_EQ(skel->bss->tcx_init_netns_cookie, cookie_expected_value, "cookie_value");
-	ASSERT_EQ(skel->bss->tcx_netns_cookie, cookie_expected_value, "cookie_value");
+	ASSERT_EQ(val, cookie_expected_value, "cookie_value_sk_msg");
+	ASSERT_EQ(skel->bss->tcx_init_netns_cookie, cookie_expected_value, "cookie_value_init_tcx");
+	ASSERT_EQ(skel->bss->tcx_netns_cookie, cookie_expected_value, "cookie_value_tcx");
+	ASSERT_EQ(skel->bss->cgroup_skb_init_netns_cookie, cookie_expected_value, "cookie_value_init_cgroup_skb");
+	ASSERT_EQ(skel->bss->cgroup_skb_netns_cookie, cookie_expected_value, "cookie_value_cgroup_skb");
 
 cleanup_tc:
 	err = bpf_prog_detach_opts(tc_fd, loopback, BPF_TCX_INGRESS, &optd);

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

@@ -28,6 +28,7 @@ struct {
 } sock_map SEC(".maps");
 
 int tcx_init_netns_cookie, tcx_netns_cookie;
+int cgroup_skb_init_netns_cookie, cgroup_skb_netns_cookie;
 
 SEC("sockops")
 int get_netns_cookie_sockops(struct bpf_sock_ops *ctx)
@@ -91,4 +92,12 @@ int get_netns_cookie_tcx(struct __sk_buff *skb)
 	return TCX_PASS;
 }
 
+SEC("cgroup_skb/ingress")
+int get_netns_cookie_cgroup_skb(struct __sk_buff *skb)
+{
+	cgroup_skb_init_netns_cookie = bpf_get_netns_cookie(NULL);
+	cgroup_skb_netns_cookie = bpf_get_netns_cookie(skb);
+	return SK_PASS;
+}
+
 char _license[] SEC("license") = "GPL";