// SPDX-License-Identifier: GPL-2.0
/*
* Test key rotation for TFO.
* New keys are 'rotated' in two steps:
* 1) Add new key as the 'backup' key 'behind' the primary key
* 2) Make new key the primary by swapping the backup and primary keys
*
* The rotation is done in stages using multiple sockets bound
* to the same port via SO_REUSEPORT. This simulates key rotation
* behind say a load balancer. We verify that across the rotation
* there are no cases in which a cookie is not accepted by verifying
* that TcpExtTCPFastOpenPassiveFail remains 0.
*/
#define _GNU_SOURCE
#include <arpa/inet.h>
#include <errno.h>
#include <error.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/epoll.h>
#include <unistd.h>
#include <netinet/tcp.h>
#include <fcntl.h>
#include <time.h>
#include "../kselftest.h"
#ifndef TCP_FASTOPEN_KEY
#define TCP_FASTOPEN_KEY 33
#endif
#define N_LISTEN 10
#define PROC_FASTOPEN_KEY "/proc/sys/net/ipv4/tcp_fastopen_key"
#define KEY_LENGTH 16
static bool do_ipv6;
static bool do_sockopt;
static bool do_rotate;
static int key_len = KEY_LENGTH;
static int rcv_fds[N_LISTEN];
static int proc_fd;
static const char *IP4_ADDR = "127.0.0.1";
static const char *IP6_ADDR = "::1";
static const int PORT = 8891;
static void get_keys(int fd, uint32_t *keys)
{
char buf[128];
socklen_t len = KEY_LENGTH * 2;
if (do_sockopt) {
if (getsockopt(fd, SOL_TCP, TCP_FASTOPEN_KEY, keys, &len))
error(1, errno, "Unable to get key");
return;
}
lseek(proc_fd, 0, SEEK_SET);
if (read(proc_fd, buf, sizeof(buf)) <= 0)
error(1, errno, "Unable to read %s", PROC_FASTOPEN_KEY);
if (sscanf(buf, "%x-%x-%x-%x,%x-%x-%x-%x", keys, keys + 1, keys + 2,
keys + 3, keys + 4, keys + 5, keys + 6, keys + 7) != 8)
error(1, 0, "Unable to parse %s", PROC_FASTOPEN_KEY);
}
static void set_keys(int fd, uint32_t *keys)
{
char buf[128];
if (do_sockopt) {
if (setsockopt(fd, SOL_TCP, TCP_FASTOPEN_KEY, keys,
key_len))
error(1, errno, "Unable to set key");
return;
}
if (do_rotate)
snprintf(buf, 128, "%08x-%08x-%08x-%08x,%08x-%08x-%08x-%08x",
keys[0], keys[1], keys[2], keys[3], keys[4], keys[5],
keys[6], keys[7]);
else
snprintf(buf, 128, "%08x-%08x-%08x-%08x",
keys[0], keys[1], keys[2], keys[3]);
lseek(proc_fd, 0, SEEK_SET);
if (write(proc_fd, buf, sizeof(buf)) <= 0)
error(1, errno, "Unable to write %s", PROC_FASTOPEN_KEY);
}
static void build_rcv_fd(int family, int proto, int *rcv_fds)
{
struct sockaddr_in addr4 = {0};
struct sockaddr_in6 addr6 = {0};
struct sockaddr *addr;
int opt = 1, i, sz;
int qlen = 100;
uint32_t keys[8];
switch (family) {
case AF_INET:
addr4.sin_family = family;
addr4.sin_addr.s_addr = htonl(INADDR_ANY);
addr4.sin_port = htons(PORT);
sz = sizeof(addr4);
addr = (struct sockaddr *)&addr4;
break;
case AF_INET6:
addr6.sin6_family = AF_INET6;
addr6.sin6_addr = in6addr_any;
addr6.sin6_port = htons(PORT);
sz = sizeof(addr6);
addr = (struct sockaddr *)&addr6;
break;
default:
error(1, 0, "Unsupported family %d", family);
/* clang does not recognize error() above as terminating
* the program, so it complains that saddr, sz are
* not initialized when this code path is taken. Silence it.
*/
return;
}
for (i = 0; i < ARRAY_SIZE(keys); i++)
keys[i] = rand();
for (i = 0; i < N_LISTEN; i++) {
rcv_fds[i] = socket(family, proto, 0);
if (rcv_fds[i] < 0)
error(1, errno, "failed to create receive socket");
if (setsockopt(rcv_fds[i], SOL_SOCKET, SO_REUSEPORT, &opt,
sizeof(opt)))
error(1, errno, "failed to set SO_REUSEPORT");
if (bind(rcv_fds[i], addr, sz))
error(1, errno, "failed to bind receive socket");
if (setsockopt(rcv_fds[i], SOL_TCP, TCP_FASTOPEN, &qlen,
sizeof(qlen)))
error(1, errno, "failed to set TCP_FASTOPEN");
set_keys(rcv_fds[i], keys);
if (proto == SOCK_STREAM && listen(rcv_fds[i], 10))
error(1, errno, "failed to listen on receive port");
}
}
static int connect_and_send(int family, int proto)
{
struct sockaddr_in saddr4 = {0};
struct sockaddr_in daddr4 = {0};
struct sockaddr_in6 saddr6 = {0};
struct sockaddr_in6 daddr6 = {0};
struct sockaddr *saddr, *daddr;
int fd, sz, ret;
char data[1];
switch (family) {
case AF_INET:
saddr4.sin_family = AF_INET;
saddr4.sin_addr.s_addr = htonl(INADDR_ANY);
saddr4.sin_port = 0;
daddr4.sin_family = AF_INET;
if (!inet_pton(family, IP4_ADDR, &daddr4.sin_addr.s_addr))
error(1, errno, "inet_pton failed: %s", IP4_ADDR);
daddr4.sin_port = htons(PORT);
sz = sizeof(saddr4);
saddr = (struct sockaddr *)&saddr4;
daddr = (struct sockaddr *)&daddr4;
break;
case AF_INET6:
saddr6.sin6_family = AF_INET6;
saddr6.sin6_addr = in6addr_any;
daddr6.sin6_family = AF_INET6;
if (!inet_pton(family, IP6_ADDR, &daddr6.sin6_addr))
error(1, errno, "inet_pton failed: %s", IP6_ADDR);
daddr6.sin6_port = htons(PORT);
sz = sizeof(saddr6);
saddr = (struct sockaddr *)&saddr6;
daddr = (struct sockaddr *)&daddr6;
break;
default:
error(1, 0, "Unsupported family %d", family);
/* clang does not recognize error() above as terminating
* the program, so it complains that saddr, daddr, sz are
* not initialized when this code path is taken. Silence it.
*/
return -1;
}
fd = socket(family, proto, 0);
if (fd < 0)
error(1, errno, "failed to create send socket");
if (bind(fd, saddr, sz))
error(1, errno, "failed to bind send socket");
data[0] = 'a';
ret = sendto(fd, data, 1, MSG_FASTOPEN, daddr, sz);
if (ret != 1)
error(1, errno, "failed to sendto");
return fd;
}
static bool is_listen_fd(int fd)
{
int i;
for (i = 0; i < N_LISTEN; i++) {
if (rcv_fds[i] == fd)
return true;
}
return false;
}
static void rotate_key(int fd)
{
static int iter;
static uint32_t new_key[4];
uint32_t keys[8];
uint32_t tmp_key[4];
int i;
if (iter < N_LISTEN) {
/* first set new key as backups */
if (iter == 0) {
for (i = 0; i < ARRAY_SIZE(new_key); i++)
new_key[i] = rand();
}
get_keys(fd, keys);
memcpy(keys + 4, new_key, KEY_LENGTH);
set_keys(fd, keys);
} else {
/* swap the keys */
get_keys(fd, keys);
memcpy(tmp_key, keys + 4, KEY_LENGTH);
memcpy(keys + 4, keys, KEY_LENGTH);
memcpy(keys, tmp_key, KEY_LENGTH);
set_keys(fd, keys);
}
if (++iter >= (N_LISTEN * 2))
iter = 0;
}
static void run_one_test(int family)
{
struct epoll_event ev;
int i, send_fd;
int n_loops = 10000;
int rotate_key_fd = 0;
int key_rotate_interval = 50;
int fd, epfd;
char buf[1];
build_rcv_fd(family, SOCK_STREAM, rcv_fds);
epfd = epoll_create(1);
if (epfd < 0)
error(1, errno, "failed to create epoll");
ev.events = EPOLLIN;
for (i = 0; i < N_LISTEN; i++) {
ev.data.fd = rcv_fds[i];
if (epoll_ctl(epfd, EPOLL_CTL_ADD, rcv_fds[i], &ev))
error(1, errno, "failed to register sock epoll");
}
while (n_loops--) {
send_fd = connect_and_send(family, SOCK_STREAM);
if (do_rotate && ((n_loops % key_rotate_interval) == 0)) {
rotate_key(rcv_fds[rotate_key_fd]);
if (++rotate_key_fd >= N_LISTEN)
rotate_key_fd = 0;
}
while (1) {
i = epoll_wait(epfd, &ev, 1, -1);
if (i < 0)
error(1, errno, "epoll_wait failed");
if (is_listen_fd(ev.data.fd)) {
fd = accept(ev.data.fd, NULL, NULL);
if (fd < 0)
error(1, errno, "failed to accept");
ev.data.fd = fd;
if (epoll_ctl(epfd, EPOLL_CTL_ADD, fd, &ev))
error(1, errno, "failed epoll add");
continue;
}
i = recv(ev.data.fd, buf, sizeof(buf), 0);
if (i != 1)
error(1, errno, "failed recv data");
if (epoll_ctl(epfd, EPOLL_CTL_DEL, ev.data.fd, NULL))
error(1, errno, "failed epoll del");
close(ev.data.fd);
break;
}
close(send_fd);
}
for (i = 0; i < N_LISTEN; i++)
close(rcv_fds[i]);
}
static void parse_opts(int argc, char **argv)
{
int c;
while ((c = getopt(argc, argv, "46sr")) != -1) {
switch (c) {
case '4':
do_ipv6 = false;
break;
case '6':
do_ipv6 = true;
break;
case 's':
do_sockopt = true;
break;
case 'r':
do_rotate = true;
key_len = KEY_LENGTH * 2;
break;
default:
error(1, 0, "%s: parse error", argv[0]);
}
}
}
int main(int argc, char **argv)
{
parse_opts(argc, argv);
proc_fd = open(PROC_FASTOPEN_KEY, O_RDWR);
if (proc_fd < 0)
error(1, errno, "Unable to open %s", PROC_FASTOPEN_KEY);
srand(time(NULL));
if (do_ipv6)
run_one_test(AF_INET6);
else
run_one_test(AF_INET);
close(proc_fd);
fprintf(stderr, "PASS\n");
return 0;
}