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}