tools/testing/selftests/bpf/prog_tests/tcp_rtt.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 #include <test_progs.h>
   3 #include "cgroup_helpers.h"
   4
   5 struct tcp_rtt_storage {
   6         __u32 invoked;
   7         __u32 dsack_dups;
   8         __u32 delivered;
   9         __u32 delivered_ce;
  10         __u32 icsk_retransmits;
  11 };
  12
  13 static 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
  21 static 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
  45 static 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
  90 static 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
 114 out:
 115         close(fd);
 116         return -1;
 117 }
 118
 119 static 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                          /*invoked=*/1,
 156                          /*dsack_dups=*/0,
 157                          /*delivered=*/1,
 158                          /*delivered_ce=*/0,
 159                          /*icsk_retransmits=*/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                          /*invoked=*/2,
 170                          /*dsack_dups=*/0,
 171                          /*delivered=*/2,
 172                          /*delivered_ce=*/0,
 173                          /*icsk_retransmits=*/0);
 174
 175 close_client_fd:
 176         close(client_fd);
 177
 178 close_bpf_object:
 179         bpf_object__close(obj);
 180         return err;
 181 }
 182
 183 static 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
 206 static pthread_mutex_t server_started_mtx = PTHREAD_MUTEX_INITIALIZER;
 207 static pthread_cond_t server_started = PTHREAD_COND_INITIALIZER;
 208
 209 static 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         /* Wait for the next connection (that never arrives)
 235          * to keep this thread alive to prevent calling
 236          * close() on client_fd.
 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
 248 void 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));
 270 close_server_fd:
 271         close(server_fd);
 272 close_cgroup_fd:
 273         close(cgroup_fd);
 274 }