selftests/bpf: Add mptcpify test

Implement a new test program mptcpify: if the family is AF_INET or
AF_INET6, the type is SOCK_STREAM, and the protocol ID is 0 or
IPPROTO_TCP, set it to IPPROTO_MPTCP. It will be hooked in
update_socket_protocol().

Extend the MPTCP test base, add a selftest test_mptcpify() for the
mptcpify case. Open and load the mptcpify test prog to mptcpify the
TCP sockets dynamically, then use start_server() and connect_to_fd()
to create a TCP socket, but actually what's created is an MPTCP
socket, which can be verified through 'getsockopt(SOL_PROTOCOL)'
and 'getsockopt(MPTCP_INFO)'.

Acked-by: Yonghong Song <yonghong.song@linux.dev>
Reviewed-by: Matthieu Baerts <matthieu.baerts@tessares.net>
Signed-off-by: Geliang Tang <geliang.tang@suse.com>
Link: https://lore.kernel.org/r/364e72f307e7bb38382ec7442c182d76298a9c41.1692147782.git.geliang.tang@suse.com
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>

diff --git a/tools/testing/selftests/bpf/prog_tests/mptcp.c b/tools/testing/selftests/bpf/prog_tests/mptcp.c
index 3d39990..7c0be7c 100644 (file)
--- a/tools/testing/selftests/bpf/prog_tests/mptcp.c
+++ b/tools/testing/selftests/bpf/prog_tests/mptcp.c
@@ -2,17 +2,59 @@
 /* Copyright (c) 2020, Tessares SA. */
 /* Copyright (c) 2022, SUSE. */
 
+#include <linux/const.h>
+#include <netinet/in.h>
 #include <test_progs.h>
 #include "cgroup_helpers.h"
 #include "network_helpers.h"
 #include "mptcp_sock.skel.h"
+#include "mptcpify.skel.h"
 
 #define NS_TEST "mptcp_ns"
 
+#ifndef IPPROTO_MPTCP
+#define IPPROTO_MPTCP 262
+#endif
+
+#ifndef SOL_MPTCP
+#define SOL_MPTCP 284
+#endif
+#ifndef MPTCP_INFO
+#define MPTCP_INFO             1
+#endif
+#ifndef MPTCP_INFO_FLAG_FALLBACK
+#define MPTCP_INFO_FLAG_FALLBACK               _BITUL(0)
+#endif
+#ifndef MPTCP_INFO_FLAG_REMOTE_KEY_RECEIVED
+#define MPTCP_INFO_FLAG_REMOTE_KEY_RECEIVED    _BITUL(1)
+#endif
+
 #ifndef TCP_CA_NAME_MAX
 #define TCP_CA_NAME_MAX        16
 #endif
 
+struct __mptcp_info {
+       __u8    mptcpi_subflows;
+       __u8    mptcpi_add_addr_signal;
+       __u8    mptcpi_add_addr_accepted;
+       __u8    mptcpi_subflows_max;
+       __u8    mptcpi_add_addr_signal_max;
+       __u8    mptcpi_add_addr_accepted_max;
+       __u32   mptcpi_flags;
+       __u32   mptcpi_token;
+       __u64   mptcpi_write_seq;
+       __u64   mptcpi_snd_una;
+       __u64   mptcpi_rcv_nxt;
+       __u8    mptcpi_local_addr_used;
+       __u8    mptcpi_local_addr_max;
+       __u8    mptcpi_csum_enabled;
+       __u32   mptcpi_retransmits;
+       __u64   mptcpi_bytes_retrans;
+       __u64   mptcpi_bytes_sent;
+       __u64   mptcpi_bytes_received;
+       __u64   mptcpi_bytes_acked;
+};
+
 struct mptcp_storage {
        __u32 invoked;
        __u32 is_mptcp;
@@ -183,8 +225,107 @@ fail:
        close(cgroup_fd);
 }
 
+static void send_byte(int fd)
+{
+       char b = 0x55;
+
+       ASSERT_EQ(write(fd, &b, sizeof(b)), 1, "send single byte");
+}
+
+static int verify_mptcpify(int server_fd, int client_fd)
+{
+       struct __mptcp_info info;
+       socklen_t optlen;
+       int protocol;
+       int err = 0;
+
+       optlen = sizeof(protocol);
+       if (!ASSERT_OK(getsockopt(server_fd, SOL_SOCKET, SO_PROTOCOL, &protocol, &optlen),
+                      "getsockopt(SOL_PROTOCOL)"))
+               return -1;
+
+       if (!ASSERT_EQ(protocol, IPPROTO_MPTCP, "protocol isn't MPTCP"))
+               err++;
+
+       optlen = sizeof(info);
+       if (!ASSERT_OK(getsockopt(client_fd, SOL_MPTCP, MPTCP_INFO, &info, &optlen),
+                      "getsockopt(MPTCP_INFO)"))
+               return -1;
+
+       if (!ASSERT_GE(info.mptcpi_flags, 0, "unexpected mptcpi_flags"))
+               err++;
+       if (!ASSERT_FALSE(info.mptcpi_flags & MPTCP_INFO_FLAG_FALLBACK,
+                         "MPTCP fallback"))
+               err++;
+       if (!ASSERT_TRUE(info.mptcpi_flags & MPTCP_INFO_FLAG_REMOTE_KEY_RECEIVED,
+                        "no remote key received"))
+               err++;
+
+       return err;
+}
+
+static int run_mptcpify(int cgroup_fd)
+{
+       int server_fd, client_fd, err = 0;
+       struct mptcpify *mptcpify_skel;
+
+       mptcpify_skel = mptcpify__open_and_load();
+       if (!ASSERT_OK_PTR(mptcpify_skel, "skel_open_load"))
+               return libbpf_get_error(mptcpify_skel);
+
+       err = mptcpify__attach(mptcpify_skel);
+       if (!ASSERT_OK(err, "skel_attach"))
+               goto out;
+
+       /* without MPTCP */
+       server_fd = start_server(AF_INET, SOCK_STREAM, NULL, 0, 0);
+       if (!ASSERT_GE(server_fd, 0, "start_server")) {
+               err = -EIO;
+               goto out;
+       }
+
+       client_fd = connect_to_fd(server_fd, 0);
+       if (!ASSERT_GE(client_fd, 0, "connect to fd")) {
+               err = -EIO;
+               goto close_server;
+       }
+
+       send_byte(client_fd);
+
+       err = verify_mptcpify(server_fd, client_fd);
+
+       close(client_fd);
+close_server:
+       close(server_fd);
+out:
+       mptcpify__destroy(mptcpify_skel);
+       return err;
+}
+
+static void test_mptcpify(void)
+{
+       struct nstoken *nstoken = NULL;
+       int cgroup_fd;
+
+       cgroup_fd = test__join_cgroup("/mptcpify");
+       if (!ASSERT_GE(cgroup_fd, 0, "test__join_cgroup"))
+               return;
+
+       nstoken = create_netns();
+       if (!ASSERT_OK_PTR(nstoken, "create_netns"))
+               goto fail;
+
+       ASSERT_OK(run_mptcpify(cgroup_fd), "run_mptcpify");
+
+fail:
+       cleanup_netns(nstoken);
+       close(cgroup_fd);
+}
+
 void test_mptcp(void)
 {
        if (test__start_subtest("base"))
                test_base();
+       if (test__start_subtest("mptcpify"))
+               test_mptcpify();
 }

diff --git a/tools/testing/selftests/bpf/progs/mptcpify.c b/tools/testing/selftests/bpf/progs/mptcpify.c
new file mode 100644 (file)
index 0000000..53301ae
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/mptcpify.c
@@ -0,0 +1,20 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (c) 2023, SUSE. */
+
+#include "vmlinux.h"
+#include <bpf/bpf_tracing.h>
+#include "bpf_tracing_net.h"
+
+char _license[] SEC("license") = "GPL";
+
+SEC("fmod_ret/update_socket_protocol")
+int BPF_PROG(mptcpify, int family, int type, int protocol)
+{
+       if ((family == AF_INET || family == AF_INET6) &&
+           type == SOCK_STREAM &&
+           (!protocol || protocol == IPPROTO_TCP)) {
+               return IPPROTO_MPTCP;
+       }
+
+       return protocol;
+}