1// SPDX-License-Identifier: GPL-2.0
  2#define _GNU_SOURCE
  3#include <test_progs.h>
  4#include "cgroup_helpers.h"
  5#include "network_helpers.h"
  6#include "tcp_rtt.skel.h"
  7
  8struct tcp_rtt_storage {
  9	__u32 invoked;
 10	__u32 dsack_dups;
 11	__u32 delivered;
 12	__u32 delivered_ce;
 13	__u32 icsk_retransmits;
 14
 15	__u32 mrtt_us;	/* args[0] */
 16	__u32 srtt;	/* args[1] */
 17};
 18
 19static void send_byte(int fd)
 20{
 21	char b = 0x55;
 22
 23	ASSERT_EQ(write(fd, &b, sizeof(b)), 1, "send single byte");
 24}
 25
 26static int wait_for_ack(int fd, int retries)
 27{
 28	struct tcp_info info;
 29	socklen_t optlen;
 30	int i, err;
 31
 32	for (i = 0; i < retries; i++) {
 33		optlen = sizeof(info);
 34		err = getsockopt(fd, SOL_TCP, TCP_INFO, &info, &optlen);
 35		if (err < 0) {
 36			log_err("Failed to lookup TCP stats");
 37			return err;
 38		}
 39
 40		if (info.tcpi_unacked == 0)
 41			return 0;
 42
 43		usleep(10);
 44	}
 45
 46	log_err("Did not receive ACK");
 47	return -1;
 48}
 49
 50static int verify_sk(int map_fd, int client_fd, const char *msg, __u32 invoked,
 51		     __u32 dsack_dups, __u32 delivered, __u32 delivered_ce,
 52		     __u32 icsk_retransmits)
 53{
 54	int err = 0;
 55	struct tcp_rtt_storage val;
 56
 57	if (!ASSERT_GE(bpf_map_lookup_elem(map_fd, &client_fd, &val), 0, "read socket storage"))
 58		return -1;
 59
 60	if (val.invoked != invoked) {
 61		log_err("%s: unexpected bpf_tcp_sock.invoked %d != %d",
 62			msg, val.invoked, invoked);
 63		err++;
 64	}
 65
 66	if (val.dsack_dups != dsack_dups) {
 67		log_err("%s: unexpected bpf_tcp_sock.dsack_dups %d != %d",
 68			msg, val.dsack_dups, dsack_dups);
 69		err++;
 70	}
 71
 72	if (val.delivered != delivered) {
 73		log_err("%s: unexpected bpf_tcp_sock.delivered %d != %d",
 74			msg, val.delivered, delivered);
 75		err++;
 76	}
 77
 78	if (val.delivered_ce != delivered_ce) {
 79		log_err("%s: unexpected bpf_tcp_sock.delivered_ce %d != %d",
 80			msg, val.delivered_ce, delivered_ce);
 81		err++;
 82	}
 83
 84	if (val.icsk_retransmits != icsk_retransmits) {
 85		log_err("%s: unexpected bpf_tcp_sock.icsk_retransmits %d != %d",
 86			msg, val.icsk_retransmits, icsk_retransmits);
 87		err++;
 88	}
 89
 90	/* Precise values of mrtt and srtt are unavailable, just make sure they are nonzero */
 91	if (val.mrtt_us == 0) {
 92		log_err("%s: unexpected bpf_tcp_sock.args[0] (mrtt_us) %u == 0", msg, val.mrtt_us);
 93		err++;
 94	}
 95
 96	if (val.srtt == 0) {
 97		log_err("%s: unexpected bpf_tcp_sock.args[1] (srtt) %u == 0", msg, val.srtt);
 98		err++;
 99	}
100
101	return err;
102}
103
104
105static int run_test(int cgroup_fd, int server_fd)
106{
107	struct tcp_rtt *skel;
108	int client_fd;
109	int prog_fd;
110	int map_fd;
111	int err;
112
113	skel = tcp_rtt__open_and_load();
114	if (!ASSERT_OK_PTR(skel, "skel_open_load"))
115		return -1;
116
117	map_fd = bpf_map__fd(skel->maps.socket_storage_map);
118	prog_fd = bpf_program__fd(skel->progs._sockops);
119
120	err = bpf_prog_attach(prog_fd, cgroup_fd, BPF_CGROUP_SOCK_OPS, 0);
121	if (err) {
122		log_err("Failed to attach BPF program");
123		goto close_bpf_object;
124	}
125
126	client_fd = connect_to_fd(server_fd, 0);
127	if (client_fd < 0) {
128		err = -1;
129		goto close_bpf_object;
130	}
131
132	err += verify_sk(map_fd, client_fd, "syn-ack",
133			 /*invoked=*/1,
134			 /*dsack_dups=*/0,
135			 /*delivered=*/1,
136			 /*delivered_ce=*/0,
137			 /*icsk_retransmits=*/0);
138
139	send_byte(client_fd);
140	if (wait_for_ack(client_fd, 100) < 0) {
141		err = -1;
142		goto close_client_fd;
143	}
144
145
146	err += verify_sk(map_fd, client_fd, "first payload byte",
147			 /*invoked=*/2,
148			 /*dsack_dups=*/0,
149			 /*delivered=*/2,
150			 /*delivered_ce=*/0,
151			 /*icsk_retransmits=*/0);
152
153close_client_fd:
154	close(client_fd);
155
156close_bpf_object:
157	tcp_rtt__destroy(skel);
158	return err;
159}
160
161void test_tcp_rtt(void)
162{
163	int server_fd, cgroup_fd;
164
165	cgroup_fd = test__join_cgroup("/tcp_rtt");
166	if (!ASSERT_GE(cgroup_fd, 0, "join_cgroup /tcp_rtt"))
167		return;
168
169	server_fd = start_server(AF_INET, SOCK_STREAM, NULL, 0, 0);
170	if (!ASSERT_GE(server_fd, 0, "start_server"))
171		goto close_cgroup_fd;
172
173	ASSERT_OK(run_test(cgroup_fd, server_fd), "run_test");
174
175	close(server_fd);
176
177close_cgroup_fd:
178	close(cgroup_fd);
179}