Exercise BPF_SOCK_OPS_TCP_TS_ID_CB end to end over IPv6 loopback.
A cgroup sock_ops program sets BPF_SOCK_OPS_TCP_TS_ID_CB_FLAG on the
listener and answers the callback. With tcp_timestamps=1 and
tcp_ts_id_bits=4 the test checks that:
- the callback runs exactly once, on the SYN, with args[1] equal to
the configured width;
- the accepted socket reports the identifier and width through
TCP_TS_ID;
- the connecting socket reports no identifier, as only passive opens
are covered;
- a reply that does not fit in the width ("decline" subtest) leaves the
accepted socket without an identifier.
The test skips when tcp_ts_id_bits does not exist and restores both
sysctls afterwards. It defines TCP_TS_ID locally when the libc headers
do not have it yet.
Signed-off-by: Willem Ferguson <[email protected]>
---
.../selftests/bpf/prog_tests/tcp_ts_id.c | 150 ++++++++++++++++++
.../selftests/bpf/progs/test_tcp_ts_id_kern.c | 32 ++++
2 files changed, 182 insertions(+)
create mode 100644 tools/testing/selftests/bpf/prog_tests/tcp_ts_id.c
create mode 100644 tools/testing/selftests/bpf/progs/test_tcp_ts_id_kern.c
diff --git a/tools/testing/selftests/bpf/prog_tests/tcp_ts_id.c
b/tools/testing/selftests/bpf/prog_tests/tcp_ts_id.c
new file mode 100644
index 000000000000..25c1f6d8dd43
--- /dev/null
+++ b/tools/testing/selftests/bpf/prog_tests/tcp_ts_id.c
@@ -0,0 +1,150 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <errno.h>
+
+#include <test_progs.h>
+#include <network_helpers.h>
+
+#include "test_tcp_ts_id_kern.skel.h"
+
+#define LO_ADDR6 "::1"
+#define CG_NAME "/tcp-ts-id-test"
+
+#ifndef TCP_TS_ID
+#define TCP_TS_ID 47
+#define TCP_TS_ID_BITS_SHIFT 8
+#endif
+
+#define TS_ID_BITS_SYSCTL "/proc/sys/net/ipv4/tcp_ts_id_bits"
+#define TIMESTAMPS_SYSCTL "/proc/sys/net/ipv4/tcp_timestamps"
+#define EXPECTED_TS_ID 7
+#define EXPECTED_TS_ID_BITS 4
+#define EXPECTED_TS_ID_BITS_STR "4"
+
+static char saved_ts_id_bits[16];
+static char saved_timestamps[16];
+
+static int save_sysctl(const char *path, char *buf)
+{
+ int err = 0;
+ FILE *f;
+
+ f = fopen(path, "r");
+ if (!f)
+ return -errno;
+
+ if (fscanf(f, "%15s", buf) != 1)
+ err = -EINVAL;
+ fclose(f);
+
+ return err;
+}
+
+static void restore_sysctl(const char *path, const char *buf)
+{
+ if (buf[0])
+ write_sysctl(path, buf);
+}
+
+static void run_ts_id_test(int cg_fd, bool decline)
+{
+ int listen_fd = -1, cli_fd = -1, accept_fd = -1;
+ struct test_tcp_ts_id_kern *skel;
+ socklen_t optlen;
+ int ts_id;
+
+ skel = test_tcp_ts_id_kern__open_and_load();
+ if (!ASSERT_OK_PTR(skel, "open_and_load"))
+ return;
+
+ skel->bss->ts_id_reply = EXPECTED_TS_ID;
+ skel->bss->ts_id_decline = decline;
+
+ skel->links.tcp_ts_id_sockops =
+ bpf_program__attach_cgroup(skel->progs.tcp_ts_id_sockops,
+ cg_fd);
+ if (!ASSERT_OK_PTR(skel->links.tcp_ts_id_sockops, "attach_cgroup"))
+ goto out;
+
+ /* The listener has to be created after the attach to get LISTEN_CB. */
+ listen_fd = start_server(AF_INET6, SOCK_STREAM, LO_ADDR6, 0, 0);
+ if (!ASSERT_NEQ(listen_fd, -1, "start_server"))
+ goto out;
+
+ cli_fd = connect_to_fd(listen_fd, 0);
+ if (!ASSERT_NEQ(cli_fd, -1, "connect_to_fd"))
+ goto out;
+
+ accept_fd = accept(listen_fd, NULL, NULL);
+ if (!ASSERT_NEQ(accept_fd, -1, "accept"))
+ goto out;
+
+ ASSERT_EQ(skel->bss->ts_id_cb_count, 1, "cb_count");
+ ASSERT_EQ(skel->bss->ts_id_cb_syn, 1, "cb_on_syn");
+ ASSERT_EQ(skel->bss->ts_id_cb_bits, EXPECTED_TS_ID_BITS, "cb_bits");
+
+ /* The identifier must reach the child socket created by the SYN. */
+ optlen = sizeof(ts_id);
+ if (ASSERT_OK(getsockopt(accept_fd, IPPROTO_TCP, TCP_TS_ID, &ts_id,
+ &optlen), "getsockopt(accept_fd, TCP_TS_ID)"))
+ ASSERT_EQ(ts_id, decline ? 0 :
+ (EXPECTED_TS_ID_BITS << TCP_TS_ID_BITS_SHIFT) |
+ EXPECTED_TS_ID, "server_ts_id");
+
+ /* Identifiers are passive-open only, so the opener must have none. */
+ optlen = sizeof(ts_id);
+ if (ASSERT_OK(getsockopt(cli_fd, IPPROTO_TCP, TCP_TS_ID, &ts_id,
+ &optlen), "getsockopt(cli_fd, TCP_TS_ID)"))
+ ASSERT_EQ(ts_id, 0, "client_ts_id");
+out:
+ if (accept_fd != -1)
+ close(accept_fd);
+ if (cli_fd != -1)
+ close(cli_fd);
+ if (listen_fd != -1)
+ close(listen_fd);
+ test_tcp_ts_id_kern__destroy(skel);
+}
+
+void test_tcp_ts_id(void)
+{
+ int cg_fd = -1;
+ int err;
+
+ err = save_sysctl(TS_ID_BITS_SYSCTL, saved_ts_id_bits);
+ if (err == -ENOENT) {
+ test__skip();
+ return;
+ }
+ if (!ASSERT_OK(err, "read " TS_ID_BITS_SYSCTL))
+ return;
+
+ if (!ASSERT_OK(save_sysctl(TIMESTAMPS_SYSCTL, saved_timestamps),
+ "read " TIMESTAMPS_SYSCTL))
+ goto out;
+
+ /* The callback only runs when timestamps are negotiated. */
+ if (!ASSERT_OK(write_sysctl(TIMESTAMPS_SYSCTL, "1"),
+ "write " TIMESTAMPS_SYSCTL))
+ goto out;
+
+ /* Identifiers are disabled by default, so the test has to opt in. */
+ if (!ASSERT_OK(write_sysctl(TS_ID_BITS_SYSCTL, EXPECTED_TS_ID_BITS_STR),
+ "write " TS_ID_BITS_SYSCTL))
+ goto out;
+
+ cg_fd = test__join_cgroup(CG_NAME);
+ if (!ASSERT_GE(cg_fd, 0, "test__join_cgroup(" CG_NAME ")"))
+ goto out;
+
+ if (test__start_subtest("assign"))
+ run_ts_id_test(cg_fd, false);
+
+ /* Only one sockops program may be attached to the cgroup at a time. */
+ if (test__start_subtest("decline"))
+ run_ts_id_test(cg_fd, true);
+out:
+ if (cg_fd != -1)
+ close(cg_fd);
+ restore_sysctl(TIMESTAMPS_SYSCTL, saved_timestamps);
+ restore_sysctl(TS_ID_BITS_SYSCTL, saved_ts_id_bits);
+}
diff --git a/tools/testing/selftests/bpf/progs/test_tcp_ts_id_kern.c
b/tools/testing/selftests/bpf/progs/test_tcp_ts_id_kern.c
new file mode 100644
index 000000000000..07e4e56c4fb1
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/test_tcp_ts_id_kern.c
@@ -0,0 +1,32 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/bpf.h>
+#include <bpf/bpf_helpers.h>
+
+__u32 ts_id_cb_count;
+__u32 ts_id_cb_syn;
+__u32 ts_id_cb_bits;
+__u32 ts_id_reply;
+__u32 ts_id_decline; /* set by userspace to exercise the decline path */
+
+SEC("sockops")
+int tcp_ts_id_sockops(struct bpf_sock_ops *skops)
+{
+ if (skops->op == BPF_SOCK_OPS_TCP_LISTEN_CB) {
+ bpf_sock_ops_cb_flags_set(skops,
+ BPF_SOCK_OPS_TCP_TS_ID_CB_FLAG);
+ return 1;
+ }
+
+ if (skops->op != BPF_SOCK_OPS_TCP_TS_ID_CB)
+ return 1;
+
+ ts_id_cb_count++;
+ ts_id_cb_syn = !!(skops->skb_tcp_flags & (1U << 1));
+ ts_id_cb_bits = skops->args[1];
+ /* -1 does not fit in Arg2 bits, so the kernel assigns no ID. */
+ skops->reply = ts_id_decline ? -1 : ts_id_reply;
+
+ return 1;
+}
+
+char _license[] SEC("license") = "GPL";
--
2.47.3
