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