1 files changed, 254 insertions, 0 deletions
diff --git a/tools/testing/selftests/bpf/test_tcp_rtt.c b/tools/testing/selftests/bpf/test_tcp_rtt.c
new file mode 100644
index 000000000000..90c3862f74a8
--- /dev/null
+++ b/tools/testing/selftests/bpf/test_tcp_rtt.c
@@ -0,0 +1,254 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <error.h>
+#include <errno.h>
+#include <stdio.h>
+#include <unistd.h>
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <netinet/in.h>
+#include <pthread.h>
+
+#include <linux/filter.h>
+#include <bpf/bpf.h>
+#include <bpf/libbpf.h>
+
+#include "bpf_rlimit.h"
+#include "bpf_util.h"
+#include "cgroup_helpers.h"
+
+#define CG_PATH                                "/tcp_rtt"
+
+struct tcp_rtt_storage {
+	__u32 invoked;
+	__u32 dsack_dups;
+	__u32 delivered;
+	__u32 delivered_ce;
+	__u32 icsk_retransmits;
+};
+
+static void send_byte(int fd)
+{
+	char b = 0x55;
+
+	if (write(fd, &b, sizeof(b)) != 1)
+		error(1, errno, "Failed to send single byte");
+}
+
+static int verify_sk(int map_fd, int client_fd, const char *msg, __u32 invoked,
+		     __u32 dsack_dups, __u32 delivered, __u32 delivered_ce,
+		     __u32 icsk_retransmits)
+{
+	int err = 0;
+	struct tcp_rtt_storage val;
+
+	if (bpf_map_lookup_elem(map_fd, &client_fd, &val) < 0)
+		error(1, errno, "Failed to read socket storage");
+
+	if (val.invoked != invoked) {
+		log_err("%s: unexpected bpf_tcp_sock.invoked %d != %d",
+			msg, val.invoked, invoked);
+		err++;
+	}
+
+	if (val.dsack_dups != dsack_dups) {
+		log_err("%s: unexpected bpf_tcp_sock.dsack_dups %d != %d",
+			msg, val.dsack_dups, dsack_dups);
+		err++;
+	}
+
+	if (val.delivered != delivered) {
+		log_err("%s: unexpected bpf_tcp_sock.delivered %d != %d",
+			msg, val.delivered, delivered);
+		err++;
+	}
+
+	if (val.delivered_ce != delivered_ce) {
+		log_err("%s: unexpected bpf_tcp_sock.delivered_ce %d != %d",
+			msg, val.delivered_ce, delivered_ce);
+		err++;
+	}
+
+	if (val.icsk_retransmits != icsk_retransmits) {
+		log_err("%s: unexpected bpf_tcp_sock.icsk_retransmits %d != %d",
+			msg, val.icsk_retransmits, icsk_retransmits);
+		err++;
+	}
+
+	return err;
+}
+
+static int connect_to_server(int server_fd)
+{
+	struct sockaddr_storage addr;
+	socklen_t len = sizeof(addr);
+	int fd;
+
+	fd = socket(AF_INET, SOCK_STREAM, 0);
+	if (fd < 0) {
+		log_err("Failed to create client socket");
+		return -1;
+	}
+
+	if (getsockname(server_fd, (struct sockaddr *)&addr, &len)) {
+		log_err("Failed to get server addr");
+		goto out;
+	}
+
+	if (connect(fd, (const struct sockaddr *)&addr, len) < 0) {
+		log_err("Fail to connect to server");
+		goto out;
+	}
+
+	return fd;
+
+out:
+	close(fd);
+	return -1;
+}
+
+static int run_test(int cgroup_fd, int server_fd)
+{
+	struct bpf_prog_load_attr attr = {
+		.prog_type = BPF_PROG_TYPE_SOCK_OPS,
+		.file = "./tcp_rtt.o",
+		.expected_attach_type = BPF_CGROUP_SOCK_OPS,
+	};
+	struct bpf_object *obj;
+	struct bpf_map *map;
+	int client_fd;
+	int prog_fd;
+	int map_fd;
+	int err;
+
+	err = bpf_prog_load_xattr(&attr, &obj, &prog_fd);
+	if (err) {
+		log_err("Failed to load BPF object");
+		return -1;
+	}
+
+	map = bpf_map__next(NULL, obj);
+	map_fd = bpf_map__fd(map);
+
+	err = bpf_prog_attach(prog_fd, cgroup_fd, BPF_CGROUP_SOCK_OPS, 0);
+	if (err) {
+		log_err("Failed to attach BPF program");
+		goto close_bpf_object;
+	}
+
+	client_fd = connect_to_server(server_fd);
+	if (client_fd < 0) {
+		err = -1;
+		goto close_bpf_object;
+	}
+
+	err += verify_sk(map_fd, client_fd, "syn-ack",
+			 /*invoked=*/1,
+			 /*dsack_dups=*/0,
+			 /*delivered=*/1,
+			 /*delivered_ce=*/0,
+			 /*icsk_retransmits=*/0);
+
+	send_byte(client_fd);
+
+	err += verify_sk(map_fd, client_fd, "first payload byte",
+			 /*invoked=*/2,
+			 /*dsack_dups=*/0,
+			 /*delivered=*/2,
+			 /*delivered_ce=*/0,
+			 /*icsk_retransmits=*/0);
+
+	close(client_fd);
+
+close_bpf_object:
+	bpf_object__close(obj);
+	return err;
+}
+
+static int start_server(void)
+{
+	struct sockaddr_in addr = {
+		.sin_family = AF_INET,
+		.sin_addr.s_addr = htonl(INADDR_LOOPBACK),
+	};
+	int fd;
+
+	fd = socket(AF_INET, SOCK_STREAM, 0);
+	if (fd < 0) {
+		log_err("Failed to create server socket");
+		return -1;
+	}
+
+	if (bind(fd, (const struct sockaddr *)&addr, sizeof(addr)) < 0) {
+		log_err("Failed to bind socket");
+		close(fd);
+		return -1;
+	}
+
+	return fd;
+}
+
+static void *server_thread(void *arg)
+{
+	struct sockaddr_storage addr;
+	socklen_t len = sizeof(addr);
+	int fd = *(int *)arg;
+	int client_fd;
+
+	if (listen(fd, 1) < 0)
+		error(1, errno, "Failed to listed on socket");
+
+	client_fd = accept(fd, (struct sockaddr *)&addr, &len);
+	if (client_fd < 0)
+		error(1, errno, "Failed to accept client");
+
+	/* Wait for the next connection (that never arrives)
+	 * to keep this thread alive to prevent calling
+	 * close() on client_fd.
+	 */
+	if (accept(fd, (struct sockaddr *)&addr, &len) >= 0)
+		error(1, errno, "Unexpected success in second accept");
+
+	close(client_fd);
+
+	return NULL;
+}
+
+int main(int args, char **argv)
+{
+	int server_fd, cgroup_fd;
+	int err = EXIT_SUCCESS;
+	pthread_t tid;
+
+	if (setup_cgroup_environment())
+		goto cleanup_obj;
+
+	cgroup_fd = create_and_get_cgroup(CG_PATH);
+	if (cgroup_fd < 0)
+		goto cleanup_cgroup_env;
+
+	if (join_cgroup(CG_PATH))
+		goto cleanup_cgroup;
+
+	server_fd = start_server();
+	if (server_fd < 0) {
+		err = EXIT_FAILURE;
+		goto cleanup_cgroup;
+	}
+
+	pthread_create(&tid, NULL, server_thread, (void *)&server_fd);
+
+	if (run_test(cgroup_fd, server_fd))
+		err = EXIT_FAILURE;
+
+	close(server_fd);
+
+	printf("test_sockopt_sk: %s\n",
+	       err == EXIT_SUCCESS ? "PASSED" : "FAILED");
+
+cleanup_cgroup:
+	close(cgroup_fd);
+cleanup_cgroup_env:
+	cleanup_cgroup_environment();
+cleanup_obj:
+	return err;
+}