2 b542d800 2021-11-20 op * Copyright (c) 2021 Omar Polo <op@omarpolo.com>
4 b542d800 2021-11-20 op * Permission to use, copy, modify, and distribute this software for any
5 b542d800 2021-11-20 op * purpose with or without fee is hereby granted, provided that the above
6 b542d800 2021-11-20 op * copyright notice and this permission notice appear in all copies.
8 b542d800 2021-11-20 op * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
9 b542d800 2021-11-20 op * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
10 b542d800 2021-11-20 op * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
11 b542d800 2021-11-20 op * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
12 b542d800 2021-11-20 op * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
13 b542d800 2021-11-20 op * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
14 b542d800 2021-11-20 op * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
17 b542d800 2021-11-20 op #include <sys/types.h>
18 b542d800 2021-11-20 op #include <sys/socket.h>
19 b542d800 2021-11-20 op #include <sys/wait.h>
21 b542d800 2021-11-20 op #include <err.h>
22 b542d800 2021-11-20 op #include <errno.h>
23 b542d800 2021-11-20 op #include <event.h>
24 b542d800 2021-11-20 op #include <limits.h>
25 b542d800 2021-11-20 op #include <netdb.h>
26 b542d800 2021-11-20 op #include <signal.h>
27 b542d800 2021-11-20 op #include <stdio.h>
28 b542d800 2021-11-20 op #include <stdlib.h>
29 b542d800 2021-11-20 op #include <string.h>
30 b542d800 2021-11-20 op #include <unistd.h>
32 b542d800 2021-11-20 op #include <stdint.h>
34 b542d800 2021-11-20 op #ifndef SSH_PATH
35 b542d800 2021-11-20 op #define SSH_PATH "/usr/bin/ssh"
38 b542d800 2021-11-20 op #define MAXSOCK 4
39 b542d800 2021-11-20 op #define MAXCONN 16
41 b542d800 2021-11-20 op int rport; /* ssh port */
42 b542d800 2021-11-20 op const char *addr; /* our addr */
43 b542d800 2021-11-20 op const char *ssh_tunnel_flag;
44 b542d800 2021-11-20 op const char *ssh_dest;
46 b542d800 2021-11-20 op struct event sockev[MAXSOCK];
47 b542d800 2021-11-20 op int socks[MAXSOCK];
50 b542d800 2021-11-20 op struct event sighupev;
51 b542d800 2021-11-20 op struct event sigintev;
52 b542d800 2021-11-20 op struct event sigtermev;
53 b542d800 2021-11-20 op struct event sigchldev;
54 b542d800 2021-11-20 op struct event siginfoev;
56 b542d800 2021-11-20 op struct timeval timeout;
57 b542d800 2021-11-20 op struct event timeoutev;
59 b542d800 2021-11-20 op pid_t ssh_pid = -1;
65 b542d800 2021-11-20 op struct bufferevent *sourcebev;
67 b542d800 2021-11-20 op struct bufferevent *tobev;
68 b542d800 2021-11-20 op } conns[MAXCONN];
71 b542d800 2021-11-20 op terminate(int fd, short event, void *data)
73 b542d800 2021-11-20 op event_loopbreak();
77 b542d800 2021-11-20 op chld(int fd, short event, void *data)
82 b542d800 2021-11-20 op if ((pid = waitpid(ssh_pid, &status, WNOHANG)) == -1)
83 b542d800 2021-11-20 op err(1, "waitpid");
87 b542d800 2021-11-20 op info(int fd, short event, void *data)
89 b542d800 2021-11-20 op warnx("connections: %d", conn);
93 b542d800 2021-11-20 op spawn_ssh(void)
95 b542d800 2021-11-20 op warnx("spawning ssh...");
97 b542d800 2021-11-20 op switch (ssh_pid = fork()) {
99 b542d800 2021-11-20 op err(1, "fork");
101 b542d800 2021-11-20 op execl(SSH_PATH, "ssh", "-L", ssh_tunnel_flag,
102 b542d800 2021-11-20 op "-NTq", ssh_dest, NULL);
103 b542d800 2021-11-20 op err(1, "exec");
105 b542d800 2021-11-20 op sleep(5); /* XXX: wait for ssh to bind the port... */
110 b542d800 2021-11-20 op killing_time(int fd, short event, void *data)
112 b542d800 2021-11-20 op if (ssh_pid == -1)
115 b542d800 2021-11-20 op warnx("killing time!");
116 b542d800 2021-11-20 op kill(ssh_pid, SIGTERM);
117 b542d800 2021-11-20 op ssh_pid = -1;
121 b542d800 2021-11-20 op nopcb(struct bufferevent *bev, void *d)
127 b542d800 2021-11-20 op sreadcb(struct bufferevent *bev, void *d)
129 b542d800 2021-11-20 op struct conn *c = d;
131 b542d800 2021-11-20 op bufferevent_write_buffer(c->tobev, EVBUFFER_INPUT(bev));
135 b542d800 2021-11-20 op treadcb(struct bufferevent *bev, void *d)
137 b542d800 2021-11-20 op struct conn *c = d;
139 b542d800 2021-11-20 op bufferevent_write_buffer(c->sourcebev, EVBUFFER_INPUT(bev));
143 b542d800 2021-11-20 op errcb(struct bufferevent *bev, short event, void *d)
145 b542d800 2021-11-20 op struct conn *c = d;
147 b542d800 2021-11-20 op warnx("in errcb, closing connection");
149 b542d800 2021-11-20 op bufferevent_free(c->sourcebev);
150 b542d800 2021-11-20 op bufferevent_free(c->tobev);
152 b542d800 2021-11-20 op close(c->source);
153 b542d800 2021-11-20 op close(c->to);
155 b542d800 2021-11-20 op c->source = -1;
158 b542d800 2021-11-20 op if (--conn == 0) {
159 b542d800 2021-11-20 op warnx("scheduling ssh termination (%lds)",
160 b542d800 2021-11-20 op timeout.tv_sec);
161 b542d800 2021-11-20 op evtimer_set(&timeoutev, killing_time, NULL);
162 b542d800 2021-11-20 op evtimer_add(&timeoutev, &timeout);
167 b542d800 2021-11-20 op connect_to_ssh(void)
169 b542d800 2021-11-20 op struct addrinfo hints, *res, *res0;
170 b542d800 2021-11-20 op int r, saved_errno, sock;
171 b542d800 2021-11-20 op char port[16];
172 b542d800 2021-11-20 op const char *c, *cause;
174 b542d800 2021-11-20 op if ((c = strchr(ssh_tunnel_flag, ':')) == NULL)
175 b542d800 2021-11-20 op errx(1, "wrong flag format: %s", ssh_tunnel_flag);
177 b542d800 2021-11-20 op if ((size_t)(c - ssh_tunnel_flag) >= sizeof(port)-1)
178 b542d800 2021-11-20 op errx(1, "EPORTTOOLONG");
180 b542d800 2021-11-20 op memset(port, 0, sizeof(port));
181 b542d800 2021-11-20 op memcpy(port, ssh_tunnel_flag, c - ssh_tunnel_flag);
183 b542d800 2021-11-20 op memset(&hints, 0, sizeof(hints));
184 b542d800 2021-11-20 op hints.ai_family = AF_UNSPEC;
185 b542d800 2021-11-20 op hints.ai_socktype = SOCK_STREAM;
187 b542d800 2021-11-20 op /* XXX: hardcoded */
188 b542d800 2021-11-20 op r = getaddrinfo("localhost", port, &hints, &res0);
190 b542d800 2021-11-20 op errx(1, "getaddrinfo(\"localhost\", \"%s\"): %s",
191 b542d800 2021-11-20 op port, gai_strerror(r));
193 b542d800 2021-11-20 op for (res = res0; res; res = res->ai_next) {
194 b542d800 2021-11-20 op sock = socket(res->ai_family, res->ai_socktype,
195 b542d800 2021-11-20 op res->ai_protocol);
196 b542d800 2021-11-20 op if (sock == -1) {
197 b542d800 2021-11-20 op cause = "socket";
201 b542d800 2021-11-20 op if (connect(sock, res->ai_addr, res->ai_addrlen) == -1) {
202 b542d800 2021-11-20 op cause = "connect";
203 b542d800 2021-11-20 op saved_errno = errno;
205 b542d800 2021-11-20 op errno = saved_errno;
213 b542d800 2021-11-20 op if (sock == -1)
214 b542d800 2021-11-20 op err(1, "%s", cause);
216 b542d800 2021-11-20 op freeaddrinfo(res0);
221 b542d800 2021-11-20 op do_accept(int fd, short event, void *data)
223 b542d800 2021-11-20 op int s, sock, i;
225 b542d800 2021-11-20 op warnx("handling connection");
227 b542d800 2021-11-20 op if (evtimer_pending(&timeoutev, NULL))
228 b542d800 2021-11-20 op evtimer_del(&timeoutev);
230 b542d800 2021-11-20 op if ((s = accept(fd, NULL, 0)) == -1)
231 b542d800 2021-11-20 op err(1, "accept");
233 b542d800 2021-11-20 op if (conn == MAXCONN) {
241 b542d800 2021-11-20 op if (ssh_pid == -1)
244 b542d800 2021-11-20 op warnx("binding the socket to ssh");
245 b542d800 2021-11-20 op sock = connect_to_ssh();
247 b542d800 2021-11-20 op for (i = 0; i < MAXCONN; ++i) {
248 b542d800 2021-11-20 op if (conns[i].source == -1) {
249 b542d800 2021-11-20 op conns[i].source = s;
250 b542d800 2021-11-20 op conns[i].to = sock;
251 b542d800 2021-11-20 op conns[i].sourcebev = bufferevent_new(s,
252 b542d800 2021-11-20 op sreadcb, nopcb, errcb, &conns[i]);
253 b542d800 2021-11-20 op conns[i].tobev = bufferevent_new(sock,
254 b542d800 2021-11-20 op treadcb, nopcb, errcb, &conns[i]);
255 b542d800 2021-11-20 op if (conns[i].sourcebev == NULL ||
256 b542d800 2021-11-20 op conns[i].tobev == NULL)
257 b542d800 2021-11-20 op err(1, "bufferevent_new");
258 b542d800 2021-11-20 op bufferevent_enable(conns[i].sourcebev,
259 b542d800 2021-11-20 op EV_READ|EV_WRITE);
260 b542d800 2021-11-20 op bufferevent_enable(conns[i].tobev,
261 b542d800 2021-11-20 op EV_READ|EV_WRITE);
267 b542d800 2021-11-20 op static void __dead
270 b542d800 2021-11-20 op fprintf(stderr, "usage: %s -B port:host:hostport -b addr [-t timeout]"
271 b542d800 2021-11-20 op " destination\n", getprogname());
276 b542d800 2021-11-20 op bind_socket(void)
278 b542d800 2021-11-20 op struct addrinfo hints, *res, *res0;
279 b542d800 2021-11-20 op int r, saved_errno;
280 b542d800 2021-11-20 op char host[64];
281 b542d800 2021-11-20 op const char *c, *h, *port, *cause;
283 b542d800 2021-11-20 op if ((c = strchr(addr, ':')) == NULL) {
287 b542d800 2021-11-20 op if ((size_t)(c - addr) >= sizeof(host) -1)
288 b542d800 2021-11-20 op errx(1, "ENAMETOOLONG");
289 b542d800 2021-11-20 op memset(host, 0, sizeof(host));
290 b542d800 2021-11-20 op memcpy(host, c, c - addr);
296 b542d800 2021-11-20 op memset(&hints, 0, sizeof(hints));
297 b542d800 2021-11-20 op hints.ai_family = AF_UNSPEC;
298 b542d800 2021-11-20 op hints.ai_socktype = SOCK_STREAM;
299 b542d800 2021-11-20 op hints.ai_flags = AI_PASSIVE;
301 b542d800 2021-11-20 op r = getaddrinfo(h, port, &hints, &res0);
303 b542d800 2021-11-20 op errx(1, "getaddrinfo(%s): %s",
304 b542d800 2021-11-20 op addr, gai_strerror(r));
306 b542d800 2021-11-20 op for (res = res0; res && nsock < MAXSOCK; res = res->ai_next) {
307 b542d800 2021-11-20 op socks[nsock] = socket(res->ai_family, res->ai_socktype,
308 b542d800 2021-11-20 op res->ai_protocol);
309 b542d800 2021-11-20 op if (socks[nsock] == -1) {
310 b542d800 2021-11-20 op cause = "socket";
314 b542d800 2021-11-20 op if (bind(socks[nsock], res->ai_addr, res->ai_addrlen) == -1) {
315 b542d800 2021-11-20 op cause = "bind";
316 b542d800 2021-11-20 op saved_errno = errno;
317 b542d800 2021-11-20 op close(socks[nsock]);
318 b542d800 2021-11-20 op errno = saved_errno;
322 b542d800 2021-11-20 op listen(socks[nsock], 5);
326 b542d800 2021-11-20 op if (nsock == 0)
327 b542d800 2021-11-20 op err(1, "%s", cause);
329 b542d800 2021-11-20 op freeaddrinfo(res0);
333 b542d800 2021-11-20 op main(int argc, char **argv)
336 b542d800 2021-11-20 op int ch, tout, i, status;
337 b542d800 2021-11-20 op const char *errstr;
339 b542d800 2021-11-20 op while ((ch = getopt(argc, argv, "B:b:t:")) != -1) {
340 b542d800 2021-11-20 op switch (ch) {
342 b542d800 2021-11-20 op ssh_tunnel_flag = optarg;
345 b542d800 2021-11-20 op addr = optarg;
348 b542d800 2021-11-20 op tout = strtonum(optarg, 1, INT_MAX, &errstr);
349 b542d800 2021-11-20 op if (errstr != NULL)
350 b542d800 2021-11-20 op errx(1, "timeout is %s: %s", errstr, optarg);
356 b542d800 2021-11-20 op argc -= optind;
357 b542d800 2021-11-20 op argv += optind;
359 b542d800 2021-11-20 op if (argc != 1 || addr == NULL || ssh_tunnel_flag == NULL)
362 b542d800 2021-11-20 op if (tout == 0)
365 b542d800 2021-11-20 op timeout.tv_sec = tout;
366 b542d800 2021-11-20 op timeout.tv_usec = 0;
368 b542d800 2021-11-20 op ssh_dest = argv[0];
370 b542d800 2021-11-20 op for (i = 0; i < MAXCONN; ++i) {
371 b542d800 2021-11-20 op conns[i].source = -1;
372 b542d800 2021-11-20 op conns[i].to = -1;
375 b542d800 2021-11-20 op bind_socket();
377 b542d800 2021-11-20 op signal(SIGPIPE, SIG_IGN);
379 b542d800 2021-11-20 op event_init();
381 b542d800 2021-11-20 op /* initialize the timer */
382 b542d800 2021-11-20 op evtimer_set(&timeoutev, killing_time, NULL);
384 b542d800 2021-11-20 op signal_set(&sighupev, SIGHUP, terminate, NULL);
385 b542d800 2021-11-20 op signal_set(&sigintev, SIGINT, terminate, NULL);
386 b542d800 2021-11-20 op signal_set(&sigtermev, SIGTERM, terminate, NULL);
387 b542d800 2021-11-20 op signal_set(&sigchldev, SIGCHLD, chld, NULL);
388 b542d800 2021-11-20 op signal_set(&siginfoev, SIGINFO, info, NULL);
390 b542d800 2021-11-20 op signal_add(&sighupev, NULL);
391 b542d800 2021-11-20 op signal_add(&sigintev, NULL);
392 b542d800 2021-11-20 op signal_add(&sigtermev, NULL);
393 b542d800 2021-11-20 op signal_add(&sigchldev, NULL);
394 b542d800 2021-11-20 op signal_add(&siginfoev, NULL);
396 b542d800 2021-11-20 op for (i = 0; i < nsock; ++i) {
397 b542d800 2021-11-20 op event_set(&sockev[i], socks[i], EV_READ|EV_PERSIST,
398 b542d800 2021-11-20 op do_accept, NULL);
399 b542d800 2021-11-20 op event_add(&sockev[i], NULL);
403 b542d800 2021-11-20 op * dns, inet: bind the socket and connect to the childs.
404 b542d800 2021-11-20 op * proc, exec: execute ssh on demand.
406 b542d800 2021-11-20 op if (pledge("stdio dns inet proc exec", NULL) == -1)
407 b542d800 2021-11-20 op err(1, "pledge");
409 b542d800 2021-11-20 op warnx("lift off!");
410 b542d800 2021-11-20 op event_dispatch();
412 b542d800 2021-11-20 op if (ssh_pid != -1)
413 b542d800 2021-11-20 op kill(ssh_pid, SIGINT);