tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
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 if (CHECK_FAIL(write(fd, &b, sizeof(b)) != 1))
20 perror("Failed to send single byte");
21}
22
23static int wait_for_ack(int fd, int retries)
24{
25 struct tcp_info info;
26 socklen_t optlen;
27 int i, err;
28
29 for (i = 0; i < retries; i++) {
30 optlen = sizeof(info);
31 err = getsockopt(fd, SOL_TCP, TCP_INFO, &info, &optlen);
32 if (err < 0) {
33 log_err("Failed to lookup TCP stats");
34 return err;
35 }
36
37 if (info.tcpi_unacked == 0)
38 return 0;
39
40 usleep(10);
41 }
42
43 log_err("Did not receive ACK");
44 return -1;
45}
46
47static int verify_sk(int map_fd, int client_fd, const char *msg, __u32 invoked,
48 __u32 dsack_dups, __u32 delivered, __u32 delivered_ce,
49 __u32 icsk_retransmits)
50{
51 int err = 0;
52 struct tcp_rtt_storage val;
53
54 if (CHECK_FAIL(bpf_map_lookup_elem(map_fd, &client_fd, &val) < 0)) {
55 perror("Failed to read socket storage");
56 return -1;
57 }
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 return err;
90}
91
92
93static int run_test(int cgroup_fd, int server_fd)
94{
95 struct tcp_rtt *skel;
96 int client_fd;
97 int prog_fd;
98 int map_fd;
99 int err;
100
101 skel = tcp_rtt__open_and_load();
102 if (!ASSERT_OK_PTR(skel, "skel_open_load"))
103 return -1;
104
105 map_fd = bpf_map__fd(skel->maps.socket_storage_map);
106 prog_fd = bpf_program__fd(skel->progs._sockops);
107
108 err = bpf_prog_attach(prog_fd, cgroup_fd, BPF_CGROUP_SOCK_OPS, 0);
109 if (err) {
110 log_err("Failed to attach BPF program");
111 goto close_bpf_object;
112 }
113
114 client_fd = connect_to_fd(server_fd, 0);
115 if (client_fd < 0) {
116 err = -1;
117 goto close_bpf_object;
118 }
119
120 err += verify_sk(map_fd, client_fd, "syn-ack",
121 /*invoked=*/1,
122 /*dsack_dups=*/0,
123 /*delivered=*/1,
124 /*delivered_ce=*/0,
125 /*icsk_retransmits=*/0);
126
127 send_byte(client_fd);
128 if (wait_for_ack(client_fd, 100) < 0) {
129 err = -1;
130 goto close_client_fd;
131 }
132
133
134 err += verify_sk(map_fd, client_fd, "first payload byte",
135 /*invoked=*/2,
136 /*dsack_dups=*/0,
137 /*delivered=*/2,
138 /*delivered_ce=*/0,
139 /*icsk_retransmits=*/0);
140
141close_client_fd:
142 close(client_fd);
143
144close_bpf_object:
145 tcp_rtt__destroy(skel);
146 return err;
147}
148
149void test_tcp_rtt(void)
150{
151 int server_fd, cgroup_fd;
152
153 cgroup_fd = test__join_cgroup("/tcp_rtt");
154 if (CHECK_FAIL(cgroup_fd < 0))
155 return;
156
157 server_fd = start_server(AF_INET, SOCK_STREAM, NULL, 0, 0);
158 if (CHECK_FAIL(server_fd < 0))
159 goto close_cgroup_fd;
160
161 CHECK_FAIL(run_test(cgroup_fd, server_fd));
162
163 close(server_fd);
164
165close_cgroup_fd:
166 close(cgroup_fd);
167}