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 72c20227 2021-11-21 op #ifndef __OpenBSD__
42 72c20227 2021-11-21 op #define pledge(p, e) 0
45 b542d800 2021-11-20 op int rport; /* ssh port */
46 b542d800 2021-11-20 op const char *addr; /* our addr */
47 b542d800 2021-11-20 op const char *ssh_tunnel_flag;
48 b542d800 2021-11-20 op const char *ssh_dest;
50 b542d800 2021-11-20 op struct event sockev[MAXSOCK];
51 b542d800 2021-11-20 op int socks[MAXSOCK];
54 b542d800 2021-11-20 op struct event sighupev;
55 b542d800 2021-11-20 op struct event sigintev;
56 b542d800 2021-11-20 op struct event sigtermev;
57 b542d800 2021-11-20 op struct event sigchldev;
58 b542d800 2021-11-20 op struct event siginfoev;
60 b542d800 2021-11-20 op struct timeval timeout;
61 b542d800 2021-11-20 op struct event timeoutev;
63 b542d800 2021-11-20 op pid_t ssh_pid = -1;
69 b542d800 2021-11-20 op struct bufferevent *sourcebev;
71 b542d800 2021-11-20 op struct bufferevent *tobev;
72 b542d800 2021-11-20 op } conns[MAXCONN];
75 b542d800 2021-11-20 op terminate(int fd, short event, void *data)
77 b542d800 2021-11-20 op event_loopbreak();
81 b542d800 2021-11-20 op chld(int fd, short event, void *data)
86 b542d800 2021-11-20 op if ((pid = waitpid(ssh_pid, &status, WNOHANG)) == -1)
87 b542d800 2021-11-20 op err(1, "waitpid");
91 b542d800 2021-11-20 op info(int fd, short event, void *data)
93 b542d800 2021-11-20 op warnx("connections: %d", conn);
97 b542d800 2021-11-20 op spawn_ssh(void)
99 b542d800 2021-11-20 op warnx("spawning ssh...");
101 b542d800 2021-11-20 op switch (ssh_pid = fork()) {
103 b542d800 2021-11-20 op err(1, "fork");
105 b542d800 2021-11-20 op execl(SSH_PATH, "ssh", "-L", ssh_tunnel_flag,
106 b542d800 2021-11-20 op "-NTq", ssh_dest, NULL);
107 b542d800 2021-11-20 op err(1, "exec");
109 b542d800 2021-11-20 op sleep(5); /* XXX: wait for ssh to bind the port... */
114 b542d800 2021-11-20 op killing_time(int fd, short event, void *data)
116 b542d800 2021-11-20 op if (ssh_pid == -1)
119 b542d800 2021-11-20 op warnx("killing time!");
120 b542d800 2021-11-20 op kill(ssh_pid, SIGTERM);
121 b542d800 2021-11-20 op ssh_pid = -1;
125 b542d800 2021-11-20 op nopcb(struct bufferevent *bev, void *d)
131 b542d800 2021-11-20 op sreadcb(struct bufferevent *bev, void *d)
133 b542d800 2021-11-20 op struct conn *c = d;
135 b542d800 2021-11-20 op bufferevent_write_buffer(c->tobev, EVBUFFER_INPUT(bev));
139 b542d800 2021-11-20 op treadcb(struct bufferevent *bev, void *d)
141 b542d800 2021-11-20 op struct conn *c = d;
143 b542d800 2021-11-20 op bufferevent_write_buffer(c->sourcebev, EVBUFFER_INPUT(bev));
147 b542d800 2021-11-20 op errcb(struct bufferevent *bev, short event, void *d)
149 b542d800 2021-11-20 op struct conn *c = d;
151 b542d800 2021-11-20 op warnx("in errcb, closing connection");
153 b542d800 2021-11-20 op bufferevent_free(c->sourcebev);
154 b542d800 2021-11-20 op bufferevent_free(c->tobev);
156 b542d800 2021-11-20 op close(c->source);
157 b542d800 2021-11-20 op close(c->to);
159 b542d800 2021-11-20 op c->source = -1;
162 b542d800 2021-11-20 op if (--conn == 0) {
163 b542d800 2021-11-20 op warnx("scheduling ssh termination (%lds)",
164 b542d800 2021-11-20 op timeout.tv_sec);
165 b542d800 2021-11-20 op evtimer_set(&timeoutev, killing_time, NULL);
166 b542d800 2021-11-20 op evtimer_add(&timeoutev, &timeout);
171 b542d800 2021-11-20 op connect_to_ssh(void)
173 b542d800 2021-11-20 op struct addrinfo hints, *res, *res0;
174 b542d800 2021-11-20 op int r, saved_errno, sock;
175 b542d800 2021-11-20 op char port[16];
176 b542d800 2021-11-20 op const char *c, *cause;
178 b542d800 2021-11-20 op if ((c = strchr(ssh_tunnel_flag, ':')) == NULL)
179 b542d800 2021-11-20 op errx(1, "wrong flag format: %s", ssh_tunnel_flag);
181 b542d800 2021-11-20 op if ((size_t)(c - ssh_tunnel_flag) >= sizeof(port)-1)
182 b542d800 2021-11-20 op errx(1, "EPORTTOOLONG");
184 b542d800 2021-11-20 op memset(port, 0, sizeof(port));
185 b542d800 2021-11-20 op memcpy(port, ssh_tunnel_flag, c - ssh_tunnel_flag);
187 b542d800 2021-11-20 op memset(&hints, 0, sizeof(hints));
188 b542d800 2021-11-20 op hints.ai_family = AF_UNSPEC;
189 b542d800 2021-11-20 op hints.ai_socktype = SOCK_STREAM;
191 b542d800 2021-11-20 op /* XXX: hardcoded */
192 b542d800 2021-11-20 op r = getaddrinfo("localhost", port, &hints, &res0);
194 b542d800 2021-11-20 op errx(1, "getaddrinfo(\"localhost\", \"%s\"): %s",
195 b542d800 2021-11-20 op port, gai_strerror(r));
197 b542d800 2021-11-20 op for (res = res0; res; res = res->ai_next) {
198 b542d800 2021-11-20 op sock = socket(res->ai_family, res->ai_socktype,
199 b542d800 2021-11-20 op res->ai_protocol);
200 b542d800 2021-11-20 op if (sock == -1) {
201 b542d800 2021-11-20 op cause = "socket";
205 b542d800 2021-11-20 op if (connect(sock, res->ai_addr, res->ai_addrlen) == -1) {
206 b542d800 2021-11-20 op cause = "connect";
207 b542d800 2021-11-20 op saved_errno = errno;
209 b542d800 2021-11-20 op errno = saved_errno;
217 b542d800 2021-11-20 op if (sock == -1)
218 b542d800 2021-11-20 op err(1, "%s", cause);
220 b542d800 2021-11-20 op freeaddrinfo(res0);
225 b542d800 2021-11-20 op do_accept(int fd, short event, void *data)
227 b542d800 2021-11-20 op int s, sock, i;
229 b542d800 2021-11-20 op warnx("handling connection");
231 b542d800 2021-11-20 op if (evtimer_pending(&timeoutev, NULL))
232 b542d800 2021-11-20 op evtimer_del(&timeoutev);
234 b542d800 2021-11-20 op if ((s = accept(fd, NULL, 0)) == -1)
235 b542d800 2021-11-20 op err(1, "accept");
237 b542d800 2021-11-20 op if (conn == MAXCONN) {
245 b542d800 2021-11-20 op if (ssh_pid == -1)
248 b542d800 2021-11-20 op warnx("binding the socket to ssh");
249 b542d800 2021-11-20 op sock = connect_to_ssh();
251 b542d800 2021-11-20 op for (i = 0; i < MAXCONN; ++i) {
252 b542d800 2021-11-20 op if (conns[i].source == -1) {
253 b542d800 2021-11-20 op conns[i].source = s;
254 b542d800 2021-11-20 op conns[i].to = sock;
255 b542d800 2021-11-20 op conns[i].sourcebev = bufferevent_new(s,
256 b542d800 2021-11-20 op sreadcb, nopcb, errcb, &conns[i]);
257 b542d800 2021-11-20 op conns[i].tobev = bufferevent_new(sock,
258 b542d800 2021-11-20 op treadcb, nopcb, errcb, &conns[i]);
259 b542d800 2021-11-20 op if (conns[i].sourcebev == NULL ||
260 b542d800 2021-11-20 op conns[i].tobev == NULL)
261 b542d800 2021-11-20 op err(1, "bufferevent_new");
262 b5e7ff9b 2021-11-21 op bufferevent_enable(conns[i].sourcebev,
263 b542d800 2021-11-20 op EV_READ|EV_WRITE);
264 b5e7ff9b 2021-11-21 op bufferevent_enable(conns[i].tobev,
265 b542d800 2021-11-20 op EV_READ|EV_WRITE);
271 b542d800 2021-11-20 op static void __dead
274 b542d800 2021-11-20 op fprintf(stderr, "usage: %s -B port:host:hostport -b addr [-t timeout]"
275 b542d800 2021-11-20 op " destination\n", getprogname());
280 b542d800 2021-11-20 op bind_socket(void)
282 b542d800 2021-11-20 op struct addrinfo hints, *res, *res0;
283 b542d800 2021-11-20 op int r, saved_errno;
284 b542d800 2021-11-20 op char host[64];
285 b542d800 2021-11-20 op const char *c, *h, *port, *cause;
287 b542d800 2021-11-20 op if ((c = strchr(addr, ':')) == NULL) {
291 b542d800 2021-11-20 op if ((size_t)(c - addr) >= sizeof(host) -1)
292 b542d800 2021-11-20 op errx(1, "ENAMETOOLONG");
293 b542d800 2021-11-20 op memset(host, 0, sizeof(host));
294 b542d800 2021-11-20 op memcpy(host, c, c - addr);
300 b542d800 2021-11-20 op memset(&hints, 0, sizeof(hints));
301 b542d800 2021-11-20 op hints.ai_family = AF_UNSPEC;
302 b542d800 2021-11-20 op hints.ai_socktype = SOCK_STREAM;
303 b542d800 2021-11-20 op hints.ai_flags = AI_PASSIVE;
305 b542d800 2021-11-20 op r = getaddrinfo(h, port, &hints, &res0);
307 b542d800 2021-11-20 op errx(1, "getaddrinfo(%s): %s",
308 b542d800 2021-11-20 op addr, gai_strerror(r));
310 b542d800 2021-11-20 op for (res = res0; res && nsock < MAXSOCK; res = res->ai_next) {
311 b542d800 2021-11-20 op socks[nsock] = socket(res->ai_family, res->ai_socktype,
312 b542d800 2021-11-20 op res->ai_protocol);
313 b542d800 2021-11-20 op if (socks[nsock] == -1) {
314 b542d800 2021-11-20 op cause = "socket";
318 b542d800 2021-11-20 op if (bind(socks[nsock], res->ai_addr, res->ai_addrlen) == -1) {
319 b542d800 2021-11-20 op cause = "bind";
320 b542d800 2021-11-20 op saved_errno = errno;
321 b542d800 2021-11-20 op close(socks[nsock]);
322 b542d800 2021-11-20 op errno = saved_errno;
326 b542d800 2021-11-20 op listen(socks[nsock], 5);
330 b542d800 2021-11-20 op if (nsock == 0)
331 b542d800 2021-11-20 op err(1, "%s", cause);
333 b542d800 2021-11-20 op freeaddrinfo(res0);
337 b542d800 2021-11-20 op main(int argc, char **argv)
340 b542d800 2021-11-20 op int ch, tout, i, status;
341 b542d800 2021-11-20 op const char *errstr;
343 b542d800 2021-11-20 op while ((ch = getopt(argc, argv, "B:b:t:")) != -1) {
344 b542d800 2021-11-20 op switch (ch) {
346 b542d800 2021-11-20 op ssh_tunnel_flag = optarg;
349 b542d800 2021-11-20 op addr = optarg;
352 b542d800 2021-11-20 op tout = strtonum(optarg, 1, INT_MAX, &errstr);
353 b542d800 2021-11-20 op if (errstr != NULL)
354 b542d800 2021-11-20 op errx(1, "timeout is %s: %s", errstr, optarg);
360 b542d800 2021-11-20 op argc -= optind;
361 b542d800 2021-11-20 op argv += optind;
363 b542d800 2021-11-20 op if (argc != 1 || addr == NULL || ssh_tunnel_flag == NULL)
366 b542d800 2021-11-20 op if (tout == 0)
369 b542d800 2021-11-20 op timeout.tv_sec = tout;
370 b542d800 2021-11-20 op timeout.tv_usec = 0;
372 b542d800 2021-11-20 op ssh_dest = argv[0];
374 b542d800 2021-11-20 op for (i = 0; i < MAXCONN; ++i) {
375 b542d800 2021-11-20 op conns[i].source = -1;
376 b542d800 2021-11-20 op conns[i].to = -1;
379 b542d800 2021-11-20 op bind_socket();
381 b542d800 2021-11-20 op signal(SIGPIPE, SIG_IGN);
383 b542d800 2021-11-20 op event_init();
385 b542d800 2021-11-20 op /* initialize the timer */
386 b542d800 2021-11-20 op evtimer_set(&timeoutev, killing_time, NULL);
388 b542d800 2021-11-20 op signal_set(&sighupev, SIGHUP, terminate, NULL);
389 b542d800 2021-11-20 op signal_set(&sigintev, SIGINT, terminate, NULL);
390 b542d800 2021-11-20 op signal_set(&sigtermev, SIGTERM, terminate, NULL);
391 b542d800 2021-11-20 op signal_set(&sigchldev, SIGCHLD, chld, NULL);
392 b542d800 2021-11-20 op signal_set(&siginfoev, SIGINFO, info, NULL);
394 b542d800 2021-11-20 op signal_add(&sighupev, NULL);
395 b542d800 2021-11-20 op signal_add(&sigintev, NULL);
396 b542d800 2021-11-20 op signal_add(&sigtermev, NULL);
397 b542d800 2021-11-20 op signal_add(&sigchldev, NULL);
398 b542d800 2021-11-20 op signal_add(&siginfoev, NULL);
400 b542d800 2021-11-20 op for (i = 0; i < nsock; ++i) {
401 b542d800 2021-11-20 op event_set(&sockev[i], socks[i], EV_READ|EV_PERSIST,
402 b542d800 2021-11-20 op do_accept, NULL);
403 b542d800 2021-11-20 op event_add(&sockev[i], NULL);
407 b542d800 2021-11-20 op * dns, inet: bind the socket and connect to the childs.
408 b542d800 2021-11-20 op * proc, exec: execute ssh on demand.
410 b542d800 2021-11-20 op if (pledge("stdio dns inet proc exec", NULL) == -1)
411 b542d800 2021-11-20 op err(1, "pledge");
413 b542d800 2021-11-20 op warnx("lift off!");
414 b542d800 2021-11-20 op event_dispatch();
416 b542d800 2021-11-20 op if (ssh_pid != -1)
417 b542d800 2021-11-20 op kill(ssh_pid, SIGINT);