[apparmor] [RFC bpf-next v7 6/6] selftests/bpf: Add mptcpify selftest

[Geliang Tang]

This patch extends 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 the outputs of 'ss' and 'nstat' commands.

Signed-off-by: Geliang Tang <geliang.t...@suse.com>
---
 .../testing/selftests/bpf/prog_tests/mptcp.c  | 94 +++++++++++++++++++
 1 file changed, 94 insertions(+)

diff --git a/tools/testing/selftests/bpf/prog_tests/mptcp.c 
b/tools/testing/selftests/bpf/prog_tests/mptcp.c
index 4407bd5c9e9a..caab3aa6a162 100644
--- a/tools/testing/selftests/bpf/prog_tests/mptcp.c
+++ b/tools/testing/selftests/bpf/prog_tests/mptcp.c
@@ -6,6 +6,7 @@
 #include "cgroup_helpers.h"
 #include "network_helpers.h"
 #include "mptcp_sock.skel.h"
+#include "mptcpify.skel.h"
 
 char NS_TEST[32];
 
@@ -195,8 +196,101 @@ static void test_base(void)
        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(void)
+{
+       char cmd[256];
+       int err = 0;
+
+       snprintf(cmd, sizeof(cmd),
+                "ip netns exec %s ss -tOni | grep -q '%s'",
+                NS_TEST, "tcp-ulp-mptcp");
+       if (!ASSERT_OK(system(cmd), "No tcp-ulp-mptcp found!"))
+               err++;
+
+       snprintf(cmd, sizeof(cmd),
+                "ip netns exec %s nstat -asz %s | awk '%s' | grep -q '%s'",
+                NS_TEST, "MPTcpExtMPCapableSYNACKRX",
+                "NR==1 {next} {print $2}", "1");
+       if (!ASSERT_OK(system(cmd), "No MPTcpExtMPCapableSYNACKRX found!"))
+               err++;
+
+       return err;
+}
+
+static int run_mptcpify(int cgroup_fd)
+{
+       int server_fd, client_fd, prog_fd, err = 0;
+       struct mptcpify *mptcpify_skel;
+
+       mptcpify_skel = mptcpify__open_and_load();
+       if (!ASSERT_OK_PTR(mptcpify_skel, "skel_open_load"))
+               return -EIO;
+
+       err = mptcpify__attach(mptcpify_skel);
+       if (!ASSERT_OK(err, "skel_attach"))
+               goto out;
+
+       prog_fd = bpf_program__fd(mptcpify_skel->progs.mptcpify);
+       if (!ASSERT_GE(prog_fd, 0, "bpf_program__fd")) {
+               err = -EIO;
+               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();
+
+       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();
 }
-- 
2.35.3