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// SPDX-License-Identifier: GPL-2.0
#include <test_progs.h>
#include "cgroup_helpers.h"
struct tcp_rtt_storage {
__u32 invoked;
__u32 dsack_dups;
__u32 delivered;
__u32 delivered_ce;
__u32 icsk_retransmits;
};
static void send_byte(int fd)
{
char b = 0x55;
if (CHECK_FAIL(write(fd, &b, sizeof(b)) != 1))
perror("Failed to send single byte");
}
static int wait_for_ack(int fd, int retries)
{
struct tcp_info info;
socklen_t optlen;
int i, err;
for (i = 0; i < retries; i++) {
optlen = sizeof(info);
err = getsockopt(fd, SOL_TCP, TCP_INFO, &info, &optlen);
if (err < 0) {
log_err("Failed to lookup TCP stats");
return err;
}
if (info.tcpi_unacked == 0)
return 0;
usleep(10);
}
log_err("Did not receive ACK");
return -1;
}
static int verify_sk(int map_fd, int client_fd, const char *msg, __u32 invoked,
__u32 dsack_dups, __u32 delivered, __u32 delivered_ce,
__u32 icsk_retransmits)
{
int err = 0;
struct tcp_rtt_storage val;
if (CHECK_FAIL(bpf_map_lookup_elem(map_fd, &client_fd, &val) < 0)) {
perror("Failed to read socket storage");
return -1;
}
if (val.invoked != invoked) {
log_err("%s: unexpected bpf_tcp_sock.invoked %d != %d",
msg, val.invoked, invoked);
err++;
}
if (val.dsack_dups != dsack_dups) {
log_err("%s: unexpected bpf_tcp_sock.dsack_dups %d != %d",
msg, val.dsack_dups, dsack_dups);
err++;
}
if (val.delivered != delivered) {
log_err("%s: unexpected bpf_tcp_sock.delivered %d != %d",
msg, val.delivered, delivered);
err++;
}
if (val.delivered_ce != delivered_ce) {
log_err("%s: unexpected bpf_tcp_sock.delivered_ce %d != %d",
msg, val.delivered_ce, delivered_ce);
err++;
}
if (val.icsk_retransmits != icsk_retransmits) {
log_err("%s: unexpected bpf_tcp_sock.icsk_retransmits %d != %d",
msg, val.icsk_retransmits, icsk_retransmits);
err++;
}
return err;
}
static int connect_to_server(int server_fd)
{
struct sockaddr_storage addr;
socklen_t len = sizeof(addr);
int fd;
fd = socket(AF_INET, SOCK_STREAM, 0);
if (fd < 0) {
log_err("Failed to create client socket");
return -1;
}
if (getsockname(server_fd, (struct sockaddr *)&addr, &len)) {
log_err("Failed to get server addr");
goto out;
}
if (connect(fd, (const struct sockaddr *)&addr, len) < 0) {
log_err("Fail to connect to server");
goto out;
}
return fd;
out:
close(fd);
return -1;
}
static int run_test(int cgroup_fd, int server_fd)
{
struct bpf_prog_load_attr attr = {
.prog_type = BPF_PROG_TYPE_SOCK_OPS,
.file = "./tcp_rtt.o",
.expected_attach_type = BPF_CGROUP_SOCK_OPS,
};
struct bpf_object *obj;
struct bpf_map *map;
int client_fd;
int prog_fd;
int map_fd;
int err;
err = bpf_prog_load_xattr(&attr, &obj, &prog_fd);
if (err) {
log_err("Failed to load BPF object");
return -1;
}
map = bpf_map__next(NULL, obj);
map_fd = bpf_map__fd(map);
err = bpf_prog_attach(prog_fd, cgroup_fd, BPF_CGROUP_SOCK_OPS, 0);
if (err) {
log_err("Failed to attach BPF program");
goto close_bpf_object;
}
client_fd = connect_to_server(server_fd);
if (client_fd < 0) {
err = -1;
goto close_bpf_object;
}
err += verify_sk(map_fd, client_fd, "syn-ack",
/*invoked=*/1,
/*dsack_dups=*/0,
/*delivered=*/1,
/*delivered_ce=*/0,
/*icsk_retransmits=*/0);
send_byte(client_fd);
if (wait_for_ack(client_fd, 100) < 0) {
err = -1;
goto close_client_fd;
}
err += verify_sk(map_fd, client_fd, "first payload byte",
/*invoked=*/2,
/*dsack_dups=*/0,
/*delivered=*/2,
/*delivered_ce=*/0,
/*icsk_retransmits=*/0);
close_client_fd:
close(client_fd);
close_bpf_object:
bpf_object__close(obj);
return err;
}
static int start_server(void)
{
struct sockaddr_in addr = {
.sin_family = AF_INET,
.sin_addr.s_addr = htonl(INADDR_LOOPBACK),
};
int fd;
fd = socket(AF_INET, SOCK_STREAM, 0);
if (fd < 0) {
log_err("Failed to create server socket");
return -1;
}
if (bind(fd, (const struct sockaddr *)&addr, sizeof(addr)) < 0) {
log_err("Failed to bind socket");
close(fd);
return -1;
}
return fd;
}
static void *server_thread(void *arg)
{
struct sockaddr_storage addr;
socklen_t len = sizeof(addr);
int fd = *(int *)arg;
int client_fd;
if (CHECK_FAIL(listen(fd, 1)) < 0) {
perror("Failed to listed on socket");
return NULL;
}
client_fd = accept(fd, (struct sockaddr *)&addr, &len);
if (CHECK_FAIL(client_fd < 0)) {
perror("Failed to accept client");
return NULL;
}
/* Wait for the next connection (that never arrives)
* to keep this thread alive to prevent calling
* close() on client_fd.
*/
if (CHECK_FAIL(accept(fd, (struct sockaddr *)&addr, &len) >= 0)) {
perror("Unexpected success in second accept");
return NULL;
}
close(client_fd);
return NULL;
}
void test_tcp_rtt(void)
{
int server_fd, cgroup_fd;
pthread_t tid;
cgroup_fd = test__join_cgroup("/tcp_rtt");
if (CHECK_FAIL(cgroup_fd < 0))
return;
server_fd = start_server();
if (CHECK_FAIL(server_fd < 0))
goto close_cgroup_fd;
pthread_create(&tid, NULL, server_thread, (void *)&server_fd);
CHECK_FAIL(run_test(cgroup_fd, server_fd));
close(server_fd);
close_cgroup_fd:
close(cgroup_fd);
}
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