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