On Fri, Apr 10, 2026 at 6:32 PM Jiayuan Chen <[email protected]> wrote: > > Add read_tcpext_snmp() helper to network_helpers which reads a > TcpExt SNMP counter via nstat, and use it in the tcp_custom_syncookie > test to verify that LINUX_MIB_SYNCOOKIESRECV is incremented and > LINUX_MIB_SYNCOOKIESFAILED stays unchanged across a successful > BPF custom syncookie validation. > > The delta is captured between start_server() and accept(), which > covers the full SYN/ACK/cookie-check path for one connection. > > Signed-off-by: Jiayuan Chen <[email protected]> > --- > tools/testing/selftests/bpf/network_helpers.c | 22 +++++++++++++++++++ > tools/testing/selftests/bpf/network_helpers.h | 1 + > .../bpf/prog_tests/tcp_custom_syncookie.c | 20 +++++++++++++++++
As you touch bpf selftest helper files, please rebase on bpf-next to avoid possible conflicts and tag bpf-next in the Subject. Change itself looks good. Reviewed-by: Kuniyuki Iwashima <[email protected]> one nit below. > 3 files changed, 43 insertions(+) > > diff --git a/tools/testing/selftests/bpf/network_helpers.c > b/tools/testing/selftests/bpf/network_helpers.c > index b82f572641b7..3388dd5112b6 100644 > --- a/tools/testing/selftests/bpf/network_helpers.c > +++ b/tools/testing/selftests/bpf/network_helpers.c > @@ -621,6 +621,28 @@ int get_socket_local_port(int sock_fd) > return -1; > } > > +int read_tcpext_snmp(const char *name, unsigned long *val) > +{ > + char cmd[128], buf[128]; > + int ret = 0; > + FILE *f; > + > + snprintf(cmd, sizeof(cmd), > + "nstat -az TcpExt%s | awk '/TcpExt/ {print $2}'", name); > + f = popen(cmd, "r"); > + if (!f) > + return -errno; > + > + if (!fgets(buf, sizeof(buf), f)) { > + ret = ferror(f) ? -errno : -ENODATA; > + goto out; > + } > + *val = strtoul(buf, NULL, 10); > +out: > + pclose(f); > + return ret; > +} > + > int get_hw_ring_size(char *ifname, struct ethtool_ringparam *ring_param) > { > struct ifreq ifr = {0}; > diff --git a/tools/testing/selftests/bpf/network_helpers.h > b/tools/testing/selftests/bpf/network_helpers.h > index 79a010c88e11..c53cd781df6e 100644 > --- a/tools/testing/selftests/bpf/network_helpers.h > +++ b/tools/testing/selftests/bpf/network_helpers.h > @@ -84,6 +84,7 @@ int make_sockaddr(int family, const char *addr_str, __u16 > port, > struct sockaddr_storage *addr, socklen_t *len); > char *ping_command(int family); > int get_socket_local_port(int sock_fd); > +int read_tcpext_snmp(const char *name, unsigned long *val); > int get_hw_ring_size(char *ifname, struct ethtool_ringparam *ring_param); > int set_hw_ring_size(char *ifname, struct ethtool_ringparam *ring_param); > > diff --git a/tools/testing/selftests/bpf/prog_tests/tcp_custom_syncookie.c > b/tools/testing/selftests/bpf/prog_tests/tcp_custom_syncookie.c > index eaf441dc7e79..6adfb4b892f8 100644 > --- a/tools/testing/selftests/bpf/prog_tests/tcp_custom_syncookie.c > +++ b/tools/testing/selftests/bpf/prog_tests/tcp_custom_syncookie.c > @@ -91,12 +91,21 @@ static void transfer_message(int sender, int receiver) > > static void create_connection(struct test_tcp_custom_syncookie_case > *test_case) > { > + unsigned long recv_before, recv_after; > + unsigned long failed_before, failed_after; While at it, please keep reverse xmas tree order > int server, client, child; > > server = start_server(test_case->family, test_case->type, > test_case->addr, 0, 0); > if (!ASSERT_NEQ(server, -1, "start_server")) > return; > > + if (!ASSERT_OK(read_tcpext_snmp("SyncookiesRecv", &recv_before), > + "read SyncookiesRecv before")) > + goto close_server; > + if (!ASSERT_OK(read_tcpext_snmp("SyncookiesFailed", &failed_before), > + "read SyncookiesFailed before")) > + goto close_server; > + > client = connect_to_fd(server, 0); > if (!ASSERT_NEQ(client, -1, "connect_to_fd")) > goto close_server; > @@ -105,9 +114,20 @@ static void create_connection(struct > test_tcp_custom_syncookie_case *test_case) > if (!ASSERT_NEQ(child, -1, "accept")) > goto close_client; > > + if (!ASSERT_OK(read_tcpext_snmp("SyncookiesRecv", &recv_after), > + "read SyncookiesRecv after")) > + goto close_child; > + if (!ASSERT_OK(read_tcpext_snmp("SyncookiesFailed", &failed_after), > + "read SyncookiesFailed after")) > + goto close_child; > + > + ASSERT_EQ(recv_after - recv_before, 1, "SyncookiesRecv delta"); > + ASSERT_EQ(failed_after - failed_before, 0, "SyncookiesFailed delta"); > + > transfer_message(client, child); > transfer_message(child, client); > > +close_child: > close(child); > close_client: > close(client); > -- > 2.43.0 >
