1 // SPDX-License-Identifier: GPL-2.0
2
3 /*
4 * Test key rotation for TFO.
5 * New keys are 'rotated' in two steps:
6 * 1) Add new key as the 'backup' key 'behind' the primary key
7 * 2) Make new key the primary by swapping the backup and primary keys
8 *
9 * The rotation is done in stages using multiple sockets bound
10 * to the same port via SO_REUSEPORT. This simulates key rotation
11 * behind say a load balancer. We verify that across the rotation
12 * there are no cases in which a cookie is not accepted by verifying
13 * that TcpExtTCPFastOpenPassiveFail remains 0.
14 */
15 #define _GNU_SOURCE
16 #include <arpa/inet.h>
17 #include <errno.h>
18 #include <error.h>
19 #include <stdbool.h>
20 #include <stdio.h>
21 #include <stdlib.h>
22 #include <string.h>
23 #include <sys/epoll.h>
24 #include <unistd.h>
25 #include <netinet/tcp.h>
26 #include <fcntl.h>
27 #include <time.h>
28
29 #ifndef TCP_FASTOPEN_KEY
30 #define TCP_FASTOPEN_KEY 33
31 #endif
32
33 #define N_LISTEN 10
34 #define PROC_FASTOPEN_KEY "/proc/sys/net/ipv4/tcp_fastopen_key"
35 #define KEY_LENGTH 16
36
37 #ifndef ARRAY_SIZE
38 #define ARRAY_SIZE(arr) (sizeof(arr) / sizeof((arr)[0]))
39 #endif
40
41 static bool do_ipv6;
42 static bool do_sockopt;
43 static bool do_rotate;
44 static int key_len = KEY_LENGTH;
45 static int rcv_fds[N_LISTEN];
46 static int proc_fd;
47 static const char *IP4_ADDR = "127.0.0.1";
48 static const char *IP6_ADDR = "::1";
49 static const int PORT = 8891;
50
get_keys(int fd,uint32_t * keys)51 static void get_keys(int fd, uint32_t *keys)
52 {
53 char buf[128];
54 socklen_t len = KEY_LENGTH * 2;
55
56 if (do_sockopt) {
57 if (getsockopt(fd, SOL_TCP, TCP_FASTOPEN_KEY, keys, &len))
58 error(1, errno, "Unable to get key");
59 return;
60 }
61 lseek(proc_fd, 0, SEEK_SET);
62 if (read(proc_fd, buf, sizeof(buf)) <= 0)
63 error(1, errno, "Unable to read %s", PROC_FASTOPEN_KEY);
64 if (sscanf(buf, "%x-%x-%x-%x,%x-%x-%x-%x", keys, keys + 1, keys + 2,
65 keys + 3, keys + 4, keys + 5, keys + 6, keys + 7) != 8)
66 error(1, 0, "Unable to parse %s", PROC_FASTOPEN_KEY);
67 }
68
set_keys(int fd,uint32_t * keys)69 static void set_keys(int fd, uint32_t *keys)
70 {
71 char buf[128];
72
73 if (do_sockopt) {
74 if (setsockopt(fd, SOL_TCP, TCP_FASTOPEN_KEY, keys,
75 key_len))
76 error(1, errno, "Unable to set key");
77 return;
78 }
79 if (do_rotate)
80 snprintf(buf, 128, "%08x-%08x-%08x-%08x,%08x-%08x-%08x-%08x",
81 keys[0], keys[1], keys[2], keys[3], keys[4], keys[5],
82 keys[6], keys[7]);
83 else
84 snprintf(buf, 128, "%08x-%08x-%08x-%08x",
85 keys[0], keys[1], keys[2], keys[3]);
86 lseek(proc_fd, 0, SEEK_SET);
87 if (write(proc_fd, buf, sizeof(buf)) <= 0)
88 error(1, errno, "Unable to write %s", PROC_FASTOPEN_KEY);
89 }
90
build_rcv_fd(int family,int proto,int * rcv_fds)91 static void build_rcv_fd(int family, int proto, int *rcv_fds)
92 {
93 struct sockaddr_in addr4 = {0};
94 struct sockaddr_in6 addr6 = {0};
95 struct sockaddr *addr;
96 int opt = 1, i, sz;
97 int qlen = 100;
98 uint32_t keys[8];
99
100 switch (family) {
101 case AF_INET:
102 addr4.sin_family = family;
103 addr4.sin_addr.s_addr = htonl(INADDR_ANY);
104 addr4.sin_port = htons(PORT);
105 sz = sizeof(addr4);
106 addr = (struct sockaddr *)&addr4;
107 break;
108 case AF_INET6:
109 addr6.sin6_family = AF_INET6;
110 addr6.sin6_addr = in6addr_any;
111 addr6.sin6_port = htons(PORT);
112 sz = sizeof(addr6);
113 addr = (struct sockaddr *)&addr6;
114 break;
115 default:
116 error(1, 0, "Unsupported family %d", family);
117 /* clang does not recognize error() above as terminating
118 * the program, so it complains that saddr, sz are
119 * not initialized when this code path is taken. Silence it.
120 */
121 return;
122 }
123 for (i = 0; i < ARRAY_SIZE(keys); i++)
124 keys[i] = rand();
125 for (i = 0; i < N_LISTEN; i++) {
126 rcv_fds[i] = socket(family, proto, 0);
127 if (rcv_fds[i] < 0)
128 error(1, errno, "failed to create receive socket");
129 if (setsockopt(rcv_fds[i], SOL_SOCKET, SO_REUSEPORT, &opt,
130 sizeof(opt)))
131 error(1, errno, "failed to set SO_REUSEPORT");
132 if (bind(rcv_fds[i], addr, sz))
133 error(1, errno, "failed to bind receive socket");
134 if (setsockopt(rcv_fds[i], SOL_TCP, TCP_FASTOPEN, &qlen,
135 sizeof(qlen)))
136 error(1, errno, "failed to set TCP_FASTOPEN");
137 set_keys(rcv_fds[i], keys);
138 if (proto == SOCK_STREAM && listen(rcv_fds[i], 10))
139 error(1, errno, "failed to listen on receive port");
140 }
141 }
142
connect_and_send(int family,int proto)143 static int connect_and_send(int family, int proto)
144 {
145 struct sockaddr_in saddr4 = {0};
146 struct sockaddr_in daddr4 = {0};
147 struct sockaddr_in6 saddr6 = {0};
148 struct sockaddr_in6 daddr6 = {0};
149 struct sockaddr *saddr, *daddr;
150 int fd, sz, ret;
151 char data[1];
152
153 switch (family) {
154 case AF_INET:
155 saddr4.sin_family = AF_INET;
156 saddr4.sin_addr.s_addr = htonl(INADDR_ANY);
157 saddr4.sin_port = 0;
158
159 daddr4.sin_family = AF_INET;
160 if (!inet_pton(family, IP4_ADDR, &daddr4.sin_addr.s_addr))
161 error(1, errno, "inet_pton failed: %s", IP4_ADDR);
162 daddr4.sin_port = htons(PORT);
163
164 sz = sizeof(saddr4);
165 saddr = (struct sockaddr *)&saddr4;
166 daddr = (struct sockaddr *)&daddr4;
167 break;
168 case AF_INET6:
169 saddr6.sin6_family = AF_INET6;
170 saddr6.sin6_addr = in6addr_any;
171
172 daddr6.sin6_family = AF_INET6;
173 if (!inet_pton(family, IP6_ADDR, &daddr6.sin6_addr))
174 error(1, errno, "inet_pton failed: %s", IP6_ADDR);
175 daddr6.sin6_port = htons(PORT);
176
177 sz = sizeof(saddr6);
178 saddr = (struct sockaddr *)&saddr6;
179 daddr = (struct sockaddr *)&daddr6;
180 break;
181 default:
182 error(1, 0, "Unsupported family %d", family);
183 /* clang does not recognize error() above as terminating
184 * the program, so it complains that saddr, daddr, sz are
185 * not initialized when this code path is taken. Silence it.
186 */
187 return -1;
188 }
189 fd = socket(family, proto, 0);
190 if (fd < 0)
191 error(1, errno, "failed to create send socket");
192 if (bind(fd, saddr, sz))
193 error(1, errno, "failed to bind send socket");
194 data[0] = 'a';
195 ret = sendto(fd, data, 1, MSG_FASTOPEN, daddr, sz);
196 if (ret != 1)
197 error(1, errno, "failed to sendto");
198
199 return fd;
200 }
201
is_listen_fd(int fd)202 static bool is_listen_fd(int fd)
203 {
204 int i;
205
206 for (i = 0; i < N_LISTEN; i++) {
207 if (rcv_fds[i] == fd)
208 return true;
209 }
210 return false;
211 }
212
rotate_key(int fd)213 static void rotate_key(int fd)
214 {
215 static int iter;
216 static uint32_t new_key[4];
217 uint32_t keys[8];
218 uint32_t tmp_key[4];
219 int i;
220
221 if (iter < N_LISTEN) {
222 /* first set new key as backups */
223 if (iter == 0) {
224 for (i = 0; i < ARRAY_SIZE(new_key); i++)
225 new_key[i] = rand();
226 }
227 get_keys(fd, keys);
228 memcpy(keys + 4, new_key, KEY_LENGTH);
229 set_keys(fd, keys);
230 } else {
231 /* swap the keys */
232 get_keys(fd, keys);
233 memcpy(tmp_key, keys + 4, KEY_LENGTH);
234 memcpy(keys + 4, keys, KEY_LENGTH);
235 memcpy(keys, tmp_key, KEY_LENGTH);
236 set_keys(fd, keys);
237 }
238 if (++iter >= (N_LISTEN * 2))
239 iter = 0;
240 }
241
run_one_test(int family)242 static void run_one_test(int family)
243 {
244 struct epoll_event ev;
245 int i, send_fd;
246 int n_loops = 10000;
247 int rotate_key_fd = 0;
248 int key_rotate_interval = 50;
249 int fd, epfd;
250 char buf[1];
251
252 build_rcv_fd(family, SOCK_STREAM, rcv_fds);
253 epfd = epoll_create(1);
254 if (epfd < 0)
255 error(1, errno, "failed to create epoll");
256 ev.events = EPOLLIN;
257 for (i = 0; i < N_LISTEN; i++) {
258 ev.data.fd = rcv_fds[i];
259 if (epoll_ctl(epfd, EPOLL_CTL_ADD, rcv_fds[i], &ev))
260 error(1, errno, "failed to register sock epoll");
261 }
262 while (n_loops--) {
263 send_fd = connect_and_send(family, SOCK_STREAM);
264 if (do_rotate && ((n_loops % key_rotate_interval) == 0)) {
265 rotate_key(rcv_fds[rotate_key_fd]);
266 if (++rotate_key_fd >= N_LISTEN)
267 rotate_key_fd = 0;
268 }
269 while (1) {
270 i = epoll_wait(epfd, &ev, 1, -1);
271 if (i < 0)
272 error(1, errno, "epoll_wait failed");
273 if (is_listen_fd(ev.data.fd)) {
274 fd = accept(ev.data.fd, NULL, NULL);
275 if (fd < 0)
276 error(1, errno, "failed to accept");
277 ev.data.fd = fd;
278 if (epoll_ctl(epfd, EPOLL_CTL_ADD, fd, &ev))
279 error(1, errno, "failed epoll add");
280 continue;
281 }
282 i = recv(ev.data.fd, buf, sizeof(buf), 0);
283 if (i != 1)
284 error(1, errno, "failed recv data");
285 if (epoll_ctl(epfd, EPOLL_CTL_DEL, ev.data.fd, NULL))
286 error(1, errno, "failed epoll del");
287 close(ev.data.fd);
288 break;
289 }
290 close(send_fd);
291 }
292 for (i = 0; i < N_LISTEN; i++)
293 close(rcv_fds[i]);
294 }
295
parse_opts(int argc,char ** argv)296 static void parse_opts(int argc, char **argv)
297 {
298 int c;
299
300 while ((c = getopt(argc, argv, "46sr")) != -1) {
301 switch (c) {
302 case '4':
303 do_ipv6 = false;
304 break;
305 case '6':
306 do_ipv6 = true;
307 break;
308 case 's':
309 do_sockopt = true;
310 break;
311 case 'r':
312 do_rotate = true;
313 key_len = KEY_LENGTH * 2;
314 break;
315 default:
316 error(1, 0, "%s: parse error", argv[0]);
317 }
318 }
319 }
320
main(int argc,char ** argv)321 int main(int argc, char **argv)
322 {
323 parse_opts(argc, argv);
324 proc_fd = open(PROC_FASTOPEN_KEY, O_RDWR);
325 if (proc_fd < 0)
326 error(1, errno, "Unable to open %s", PROC_FASTOPEN_KEY);
327 srand(time(NULL));
328 if (do_ipv6)
329 run_one_test(AF_INET6);
330 else
331 run_one_test(AF_INET);
332 close(proc_fd);
333 fprintf(stderr, "PASS\n");
334 return 0;
335 }
336