Add a sockops test program that enables BPF_SOCK_OPS_WRITE_HDR_OPT_CB_FLAG on connection setup and calls bpf_setsockopt(TCP_NODELAY) from BPF_SOCK_OPS_HDR_OPT_LEN_CB.
Exercise the connection by sending data after the socket is established. Before the fix, this setup can recurse through tcp_push_pending_frames() and bpf_skops_hdr_opt_len() until the kernel hits a stack guard page. After the fix, the connection continues to make forward progress and the data exchange completes. Signed-off-by: KaFai Wan <[email protected]> --- .../bpf/prog_tests/tcp_hdr_options.c | 34 +++++++++++++++++++ .../bpf/progs/test_misc_tcp_hdr_options.c | 18 ++++++++++ 2 files changed, 52 insertions(+) diff --git a/tools/testing/selftests/bpf/prog_tests/tcp_hdr_options.c b/tools/testing/selftests/bpf/prog_tests/tcp_hdr_options.c index 56685fc03c7e..f361f9c7bf59 100644 --- a/tools/testing/selftests/bpf/prog_tests/tcp_hdr_options.c +++ b/tools/testing/selftests/bpf/prog_tests/tcp_hdr_options.c @@ -513,6 +513,39 @@ static void misc(void) bpf_link__destroy(link); } +static void hdr_sockopt(void) +{ + const char send_msg[] = "MISC!!!"; + char recv_msg[sizeof(send_msg)]; + const unsigned int nr_data = 2; + struct bpf_link *link; + struct sk_fds sk_fds; + int i, ret; + + link = bpf_program__attach_cgroup(misc_skel->progs.misc_hdr_sockopt, cg_fd); + if (!ASSERT_OK_PTR(link, "attach_cgroup(misc_hdr_sockopt)")) + return; + + if (sk_fds_connect(&sk_fds, false)) { + bpf_link__destroy(link); + return; + } + + for (i = 0; i < nr_data; i++) { + ret = send(sk_fds.active_fd, send_msg, sizeof(send_msg), 0); + if (!ASSERT_EQ(ret, sizeof(send_msg), "send(msg)")) + goto check_linum; + + ret = read(sk_fds.passive_fd, recv_msg, sizeof(recv_msg)); + if (!ASSERT_EQ(ret, sizeof(send_msg), "read(msg)")) + goto check_linum; + } + +check_linum: + sk_fds_close(&sk_fds); + bpf_link__destroy(link); +} + struct test { const char *desc; void (*run)(void); @@ -526,6 +559,7 @@ static struct test tests[] = { DEF_TEST(fastopen_estab), DEF_TEST(fin), DEF_TEST(misc), + DEF_TEST(hdr_sockopt), }; void test_tcp_hdr_options(void) diff --git a/tools/testing/selftests/bpf/progs/test_misc_tcp_hdr_options.c b/tools/testing/selftests/bpf/progs/test_misc_tcp_hdr_options.c index d487153a839d..e1dc7246193e 100644 --- a/tools/testing/selftests/bpf/progs/test_misc_tcp_hdr_options.c +++ b/tools/testing/selftests/bpf/progs/test_misc_tcp_hdr_options.c @@ -326,4 +326,22 @@ int misc_estab(struct bpf_sock_ops *skops) return CG_OK; } +SEC("sockops") +int misc_hdr_sockopt(struct bpf_sock_ops *skops) +{ + int true_val = 1; + + switch (skops->op) { + case BPF_SOCK_OPS_ACTIVE_ESTABLISHED_CB: + case BPF_SOCK_OPS_PASSIVE_ESTABLISHED_CB: + set_hdr_cb_flags(skops, 0); + break; + case BPF_SOCK_OPS_HDR_OPT_LEN_CB: + bpf_setsockopt(skops, SOL_TCP, TCP_NODELAY, &true_val, sizeof(true_val)); + break; + } + + return 0; +} + char _license[] SEC("license") = "GPL"; -- 2.43.0
