selftests/bpf: Test for get_socket_cookie

Add test to use get_socket_cookie() from BPF programs of types
BPF_PROG_TYPE_SOCK_OPS and BPF_PROG_TYPE_CGROUP_SOCK_ADDR.

The test attaches two programs to cgroup, runs TCP server and client in
the cgroup and checks that two operations are done properly on client
socket when user calls connect(2):

1. In BPF_CGROUP_INET6_CONNECT socket cookie is used as the key to write
   new value in a map for client socket.

2. In BPF_CGROUP_SOCK_OPS (BPF_SOCK_OPS_TCP_CONNECT_CB callback) the
   value written in "1." is found by socket cookie, since it's the same
   socket, and updated.

Finally the test verifies the value in the map.

Signed-off-by: Andrey Ignatov <rdna@fb.com>
Acked-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

1 files changed, 60 insertions, 0 deletions

diff --git a/tools/testing/selftests/bpf/socket_cookie_prog.c b/tools/testing/selftests/bpf/socket_cookie_prog.c
new file mode 100644
index 000000000000..9ff8ac4b0bf6
--- /dev/null
+++ b/tools/testing/selftests/bpf/socket_cookie_prog.c
@@ -0,0 +1,60 @@
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (c) 2018 Facebook
+
+#include <linux/bpf.h>
+#include <sys/socket.h>
+
+#include "bpf_helpers.h"
+#include "bpf_endian.h"
+
+struct bpf_map_def SEC("maps") socket_cookies = {
+	.type = BPF_MAP_TYPE_HASH,
+	.key_size = sizeof(__u64),
+	.value_size = sizeof(__u32),
+	.max_entries = 1 << 8,
+};
+
+SEC("cgroup/connect6")
+int set_cookie(struct bpf_sock_addr *ctx)
+{
+	__u32 cookie_value = 0xFF;
+	__u64 cookie_key;
+
+	if (ctx->family != AF_INET6 || ctx->user_family != AF_INET6)
+		return 1;
+
+	cookie_key = bpf_get_socket_cookie(ctx);
+	if (bpf_map_update_elem(&socket_cookies, &cookie_key, &cookie_value, 0))
+		return 0;
+
+	return 1;
+}
+
+SEC("sockops")
+int update_cookie(struct bpf_sock_ops *ctx)
+{
+	__u32 new_cookie_value;
+	__u32 *cookie_value;
+	__u64 cookie_key;
+
+	if (ctx->family != AF_INET6)
+		return 1;
+
+	if (ctx->op != BPF_SOCK_OPS_TCP_CONNECT_CB)
+		return 1;
+
+	cookie_key = bpf_get_socket_cookie(ctx);
+
+	cookie_value = bpf_map_lookup_elem(&socket_cookies, &cookie_key);
+	if (!cookie_value)
+		return 1;
+
+	new_cookie_value = (ctx->local_port << 8) | *cookie_value;
+	bpf_map_update_elem(&socket_cookies, &cookie_key, &new_cookie_value, 0);
+
+	return 1;
+}
+
+int _version SEC("version") = 1;
+
+char _license[] SEC("license") = "GPL";