1
2#include <test_progs.h>
3#include "cgroup_helpers.h"
4
5struct tcp_rtt_storage {
6 __u32 invoked;
7 __u32 dsack_dups;
8 __u32 delivered;
9 __u32 delivered_ce;
10 __u32 icsk_retransmits;
11};
12
13static void send_byte(int fd)
14{
15 char b = 0x55;
16
17 if (CHECK_FAIL(write(fd, &b, sizeof(b)) != 1))
18 perror("Failed to send single byte");
19}
20
21static int wait_for_ack(int fd, int retries)
22{
23 struct tcp_info info;
24 socklen_t optlen;
25 int i, err;
26
27 for (i = 0; i < retries; i++) {
28 optlen = sizeof(info);
29 err = getsockopt(fd, SOL_TCP, TCP_INFO, &info, &optlen);
30 if (err < 0) {
31 log_err("Failed to lookup TCP stats");
32 return err;
33 }
34
35 if (info.tcpi_unacked == 0)
36 return 0;
37
38 usleep(10);
39 }
40
41 log_err("Did not receive ACK");
42 return -1;
43}
44
45static int verify_sk(int map_fd, int client_fd, const char *msg, __u32 invoked,
46 __u32 dsack_dups, __u32 delivered, __u32 delivered_ce,
47 __u32 icsk_retransmits)
48{
49 int err = 0;
50 struct tcp_rtt_storage val;
51
52 if (CHECK_FAIL(bpf_map_lookup_elem(map_fd, &client_fd, &val) < 0)) {
53 perror("Failed to read socket storage");
54 return -1;
55 }
56
57 if (val.invoked != invoked) {
58 log_err("%s: unexpected bpf_tcp_sock.invoked %d != %d",
59 msg, val.invoked, invoked);
60 err++;
61 }
62
63 if (val.dsack_dups != dsack_dups) {
64 log_err("%s: unexpected bpf_tcp_sock.dsack_dups %d != %d",
65 msg, val.dsack_dups, dsack_dups);
66 err++;
67 }
68
69 if (val.delivered != delivered) {
70 log_err("%s: unexpected bpf_tcp_sock.delivered %d != %d",
71 msg, val.delivered, delivered);
72 err++;
73 }
74
75 if (val.delivered_ce != delivered_ce) {
76 log_err("%s: unexpected bpf_tcp_sock.delivered_ce %d != %d",
77 msg, val.delivered_ce, delivered_ce);
78 err++;
79 }
80
81 if (val.icsk_retransmits != icsk_retransmits) {
82 log_err("%s: unexpected bpf_tcp_sock.icsk_retransmits %d != %d",
83 msg, val.icsk_retransmits, icsk_retransmits);
84 err++;
85 }
86
87 return err;
88}
89
90static int connect_to_server(int server_fd)
91{
92 struct sockaddr_storage addr;
93 socklen_t len = sizeof(addr);
94 int fd;
95
96 fd = socket(AF_INET, SOCK_STREAM, 0);
97 if (fd < 0) {
98 log_err("Failed to create client socket");
99 return -1;
100 }
101
102 if (getsockname(server_fd, (struct sockaddr *)&addr, &len)) {
103 log_err("Failed to get server addr");
104 goto out;
105 }
106
107 if (connect(fd, (const struct sockaddr *)&addr, len) < 0) {
108 log_err("Fail to connect to server");
109 goto out;
110 }
111
112 return fd;
113
114out:
115 close(fd);
116 return -1;
117}
118
119static int run_test(int cgroup_fd, int server_fd)
120{
121 struct bpf_prog_load_attr attr = {
122 .prog_type = BPF_PROG_TYPE_SOCK_OPS,
123 .file = "./tcp_rtt.o",
124 .expected_attach_type = BPF_CGROUP_SOCK_OPS,
125 };
126 struct bpf_object *obj;
127 struct bpf_map *map;
128 int client_fd;
129 int prog_fd;
130 int map_fd;
131 int err;
132
133 err = bpf_prog_load_xattr(&attr, &obj, &prog_fd);
134 if (err) {
135 log_err("Failed to load BPF object");
136 return -1;
137 }
138
139 map = bpf_map__next(NULL, obj);
140 map_fd = bpf_map__fd(map);
141
142 err = bpf_prog_attach(prog_fd, cgroup_fd, BPF_CGROUP_SOCK_OPS, 0);
143 if (err) {
144 log_err("Failed to attach BPF program");
145 goto close_bpf_object;
146 }
147
148 client_fd = connect_to_server(server_fd);
149 if (client_fd < 0) {
150 err = -1;
151 goto close_bpf_object;
152 }
153
154 err += verify_sk(map_fd, client_fd, "syn-ack",
155 1,
156 0,
157 1,
158 0,
159 0);
160
161 send_byte(client_fd);
162 if (wait_for_ack(client_fd, 100) < 0) {
163 err = -1;
164 goto close_client_fd;
165 }
166
167
168 err += verify_sk(map_fd, client_fd, "first payload byte",
169 2,
170 0,
171 2,
172 0,
173 0);
174
175close_client_fd:
176 close(client_fd);
177
178close_bpf_object:
179 bpf_object__close(obj);
180 return err;
181}
182
183static int start_server(void)
184{
185 struct sockaddr_in addr = {
186 .sin_family = AF_INET,
187 .sin_addr.s_addr = htonl(INADDR_LOOPBACK),
188 };
189 int fd;
190
191 fd = socket(AF_INET, SOCK_STREAM, 0);
192 if (fd < 0) {
193 log_err("Failed to create server socket");
194 return -1;
195 }
196
197 if (bind(fd, (const struct sockaddr *)&addr, sizeof(addr)) < 0) {
198 log_err("Failed to bind socket");
199 close(fd);
200 return -1;
201 }
202
203 return fd;
204}
205
206static pthread_mutex_t server_started_mtx = PTHREAD_MUTEX_INITIALIZER;
207static pthread_cond_t server_started = PTHREAD_COND_INITIALIZER;
208
209static void *server_thread(void *arg)
210{
211 struct sockaddr_storage addr;
212 socklen_t len = sizeof(addr);
213 int fd = *(int *)arg;
214 int client_fd;
215 int err;
216
217 err = listen(fd, 1);
218
219 pthread_mutex_lock(&server_started_mtx);
220 pthread_cond_signal(&server_started);
221 pthread_mutex_unlock(&server_started_mtx);
222
223 if (CHECK_FAIL(err < 0)) {
224 perror("Failed to listed on socket");
225 return NULL;
226 }
227
228 client_fd = accept(fd, (struct sockaddr *)&addr, &len);
229 if (CHECK_FAIL(client_fd < 0)) {
230 perror("Failed to accept client");
231 return NULL;
232 }
233
234
235
236
237
238 if (CHECK_FAIL(accept(fd, (struct sockaddr *)&addr, &len) >= 0)) {
239 perror("Unexpected success in second accept");
240 return NULL;
241 }
242
243 close(client_fd);
244
245 return NULL;
246}
247
248void test_tcp_rtt(void)
249{
250 int server_fd, cgroup_fd;
251 pthread_t tid;
252
253 cgroup_fd = test__join_cgroup("/tcp_rtt");
254 if (CHECK_FAIL(cgroup_fd < 0))
255 return;
256
257 server_fd = start_server();
258 if (CHECK_FAIL(server_fd < 0))
259 goto close_cgroup_fd;
260
261 if (CHECK_FAIL(pthread_create(&tid, NULL, server_thread,
262 (void *)&server_fd)))
263 goto close_server_fd;
264
265 pthread_mutex_lock(&server_started_mtx);
266 pthread_cond_wait(&server_started, &server_started_mtx);
267 pthread_mutex_unlock(&server_started_mtx);
268
269 CHECK_FAIL(run_test(cgroup_fd, server_fd));
270close_server_fd:
271 close(server_fd);
272close_cgroup_fd:
273 close(cgroup_fd);
274}
275
