19 const struct plug_function_table *fn;
20 /* the above variable absolutely *must* be the first in this structure */
21 void *c; /* (channel) data used by ssh.c */
22 void *backhandle; /* instance of SSH backend itself */
23 /* Note that backhandle need not be filled in if c is non-NULL */
25 int throttled, throttle_override;
28 * `dynamic' does double duty. It's set to 0 for an ordinary
29 * forwarded port, and nonzero for SOCKS-style dynamic port
30 * forwarding; but it also represents the state of the SOCKS
35 * `hostname' and `port' are the real hostname and port, once
36 * we know what we're connecting to.
41 * `socksbuf' is the buffer we use to accumulate a SOCKS request.
44 int sockslen, sockssize;
46 * When doing dynamic port forwarding, we can receive
47 * connection data before we are actually able to send it; so
48 * we may have to temporarily hold some in a dynamically
49 * allocated buffer here.
55 static struct PFwdPrivate *new_portfwd_private(void)
57 struct PFwdPrivate *pr = snew(struct PFwdPrivate);
60 pr->sockslen = pr->sockssize = 0;
65 static void free_portfwd_private(struct PFwdPrivate *pr)
75 static void pfd_log(Plug plug, int type, SockAddr addr, int port,
76 const char *error_msg, int error_code)
78 /* we have to dump these since we have no interface to logging.c */
81 static int pfd_closing(Plug plug, const char *error_msg, int error_code,
84 struct PFwdPrivate *pr = (struct PFwdPrivate *) plug;
88 * Socket error. Slam the connection instantly shut.
90 sshfwd_unclean_close(pr->c);
93 * Ordinary EOF received on socket. Send an EOF on the SSH
97 sshfwd_write_eof(pr->c);
103 static int pfd_receive(Plug plug, int urgent, char *data, int len)
105 struct PFwdPrivate *pr = (struct PFwdPrivate *) plug;
108 if (pr->sockslen >= pr->sockssize) {
109 pr->sockssize = pr->sockslen * 5 / 4 + 256;
110 pr->socksbuf = sresize(pr->socksbuf, pr->sockssize, char);
112 pr->socksbuf[pr->sockslen++] = *data++;
115 * Now check what's in the buffer to see if it's a
116 * valid and complete message in the SOCKS exchange.
118 if ((pr->dynamic == 1 || (pr->dynamic >> 12) == 4) &&
119 pr->socksbuf[0] == 4) {
123 if (pr->dynamic == 1)
124 pr->dynamic = 0x4000;
125 if (pr->sockslen < 2)
126 continue; /* don't have command code yet */
127 if (pr->socksbuf[1] != 1) {
129 /* Send back a SOCKS 4 error before closing. */
131 memset(data, 0, sizeof(data));
132 data[1] = 91; /* generic `request rejected' */
133 sk_write(pr->s, data, 8);
137 if (pr->sockslen <= 8)
138 continue; /* haven't started user/hostname */
139 if (pr->socksbuf[pr->sockslen-1] != 0)
140 continue; /* haven't _finished_ user/hostname */
142 * Now we have a full SOCKS 4 request. Check it to
143 * see if it's a SOCKS 4A request.
145 if (pr->socksbuf[4] == 0 && pr->socksbuf[5] == 0 &&
146 pr->socksbuf[6] == 0 && pr->socksbuf[7] != 0) {
148 * It's SOCKS 4A. So if we haven't yet
149 * collected the host name, we should continue
150 * waiting for data in order to do so; if we
151 * have, we can go ahead.
154 if (pr->dynamic == 0x4000) {
155 pr->dynamic = 0x4001;
156 pr->sockslen = 8; /* reset buffer to overwrite name */
159 pr->socksbuf[0] = 0; /* reply version code */
160 pr->socksbuf[1] = 90; /* request granted */
161 sk_write(pr->s, pr->socksbuf, 8);
162 len = pr->sockslen - 8;
163 pr->port = GET_16BIT_MSB_FIRST(pr->socksbuf+2);
164 pr->hostname = snewn(len+1, char);
165 pr->hostname[len] = '\0';
166 memcpy(pr->hostname, pr->socksbuf + 8, len);
170 * It's SOCKS 4, which means we should format
171 * the IP address into the hostname string and
174 pr->socksbuf[0] = 0; /* reply version code */
175 pr->socksbuf[1] = 90; /* request granted */
176 sk_write(pr->s, pr->socksbuf, 8);
177 pr->port = GET_16BIT_MSB_FIRST(pr->socksbuf+2);
178 pr->hostname = dupprintf("%d.%d.%d.%d",
179 (unsigned char)pr->socksbuf[4],
180 (unsigned char)pr->socksbuf[5],
181 (unsigned char)pr->socksbuf[6],
182 (unsigned char)pr->socksbuf[7]);
187 if ((pr->dynamic == 1 || (pr->dynamic >> 12) == 5) &&
188 pr->socksbuf[0] == 5) {
192 if (pr->dynamic == 1)
193 pr->dynamic = 0x5000;
195 if (pr->dynamic == 0x5000) {
199 * We're receiving a set of method identifiers.
201 if (pr->sockslen < 2)
202 continue; /* no method count yet */
203 if (pr->sockslen < 2 + (unsigned char)pr->socksbuf[1])
204 continue; /* no methods yet */
205 method = 0xFF; /* invalid */
206 for (i = 0; i < (unsigned char)pr->socksbuf[1]; i++)
207 if (pr->socksbuf[2+i] == 0) {
208 method = 0;/* no auth */
213 sk_write(pr->s, data, 2);
214 pr->dynamic = 0x5001;
215 pr->sockslen = 0; /* re-empty the buffer */
219 if (pr->dynamic == 0x5001) {
221 * We're receiving a SOCKS request.
223 unsigned char reply[10]; /* SOCKS5 atyp=1 reply */
227 * Pre-fill reply packet.
228 * In all cases, we set BND.{HOST,ADDR} to 0.0.0.0:0
229 * (atyp=1) in the reply; if we succeed, we don't know
230 * the right answers, and if we fail, they should be
233 memset(reply, 0, lenof(reply));
234 reply[0] = 5; /* VER */
235 reply[3] = 1; /* ATYP = 1 (IPv4, 0.0.0.0:0) */
237 if (pr->sockslen < 6) continue;
238 atype = (unsigned char)pr->socksbuf[3];
239 if (atype == 1) /* IPv4 address */
241 if (atype == 4) /* IPv6 address */
243 if (atype == 3) /* domain name has leading length */
244 alen = 1 + (unsigned char)pr->socksbuf[4];
245 if (pr->sockslen < 6 + alen) continue;
246 if (pr->socksbuf[1] != 1 || pr->socksbuf[2] != 0) {
247 /* Not CONNECT or reserved field nonzero - error */
248 reply[1] = 1; /* generic failure */
249 sk_write(pr->s, (char *) reply, lenof(reply));
254 * Now we have a viable connect request. Switch
257 pr->port = GET_16BIT_MSB_FIRST(pr->socksbuf+4+alen);
259 /* REP=0 (success) already */
260 sk_write(pr->s, (char *) reply, lenof(reply));
261 pr->hostname = dupprintf("%d.%d.%d.%d",
262 (unsigned char)pr->socksbuf[4],
263 (unsigned char)pr->socksbuf[5],
264 (unsigned char)pr->socksbuf[6],
265 (unsigned char)pr->socksbuf[7]);
267 } else if (atype == 3) {
268 /* REP=0 (success) already */
269 sk_write(pr->s, (char *) reply, lenof(reply));
270 pr->hostname = snewn(alen, char);
271 pr->hostname[alen-1] = '\0';
272 memcpy(pr->hostname, pr->socksbuf + 5, alen-1);
276 * Unknown address type. (FIXME: support IPv6!)
278 reply[1] = 8; /* atype not supported */
279 sk_write(pr->s, (char *) reply, lenof(reply));
287 * If we get here without either having done `continue'
288 * or `goto connect', it must be because there is no
289 * sensible interpretation of what's in our buffer. So
290 * close the connection rudely.
298 * We come here when we're ready to make an actual
306 * Freeze the socket until the SSH server confirms the
309 sk_set_frozen(pr->s, 1);
311 pr->c = new_sock_channel(pr->backhandle, pr->s);
316 /* asks to forward to the specified host/port for this */
317 ssh_send_port_open(pr->c, pr->hostname, pr->port, "forwarding");
322 * If there's any data remaining in our current buffer,
323 * save it to be sent on pfd_confirm().
326 pr->buffer = snewn(len, char);
327 memcpy(pr->buffer, data, len);
332 if (sshfwd_write(pr->c, data, len) > 0) {
334 sk_set_frozen(pr->s, 1);
340 static void pfd_sent(Plug plug, int bufsize)
342 struct PFwdPrivate *pr = (struct PFwdPrivate *) plug;
345 sshfwd_unthrottle(pr->c, bufsize);
349 * Called when receiving a PORT OPEN from the server
351 const char *pfd_newconnect(Socket *s, char *hostname, int port,
352 void *c, Conf *conf, int addressfamily)
354 static const struct plug_function_table fn_table = {
364 char *dummy_realhost;
365 struct PFwdPrivate *pr;
370 addr = name_lookup(hostname, port, &dummy_realhost, conf, addressfamily);
371 if ((err = sk_addr_error(addr)) != NULL) {
373 sfree(dummy_realhost);
380 pr = new_portfwd_private();
382 pr->throttled = pr->throttle_override = 0;
385 pr->backhandle = NULL; /* we shouldn't need this */
388 pr->s = *s = new_connection(addr, dummy_realhost, port,
389 0, 1, 0, 0, (Plug) pr, conf);
390 sfree(dummy_realhost);
391 if ((err = sk_socket_error(*s)) != NULL) {
392 free_portfwd_private(pr);
396 sk_set_private_ptr(*s, pr);
401 called when someone connects to the local port
404 static int pfd_accepting(Plug p, OSSocket sock)
406 static const struct plug_function_table fn_table = {
413 struct PFwdPrivate *pr, *org;
417 org = (struct PFwdPrivate *)p;
418 pr = new_portfwd_private();
422 pr->backhandle = org->backhandle;
424 pr->s = s = sk_register(sock, (Plug) pr);
425 if ((err = sk_socket_error(s)) != NULL) {
426 free_portfwd_private(pr);
430 sk_set_private_ptr(s, pr);
432 pr->throttled = pr->throttle_override = 0;
437 pr->port = 0; /* "hostname" buffer is so far empty */
438 sk_set_frozen(s, 0); /* we want to receive SOCKS _now_! */
441 pr->hostname = dupstr(org->hostname);
442 pr->port = org->port;
443 pr->c = new_sock_channel(org->backhandle, s);
446 free_portfwd_private(pr);
449 /* asks to forward to the specified host/port for this */
450 ssh_send_port_open(pr->c, pr->hostname, pr->port, "forwarding");
458 /* Add a new forwarding from port -> desthost:destport
459 sets up a listener on the local machine on (srcaddr:)port
461 const char *pfd_addforward(char *desthost, int destport, char *srcaddr,
462 int port, void *backhandle, Conf *conf,
463 void **sockdata, int address_family)
465 static const struct plug_function_table fn_table = {
468 pfd_receive, /* should not happen... */
469 pfd_sent, /* also should not happen */
474 struct PFwdPrivate *pr;
480 pr = new_portfwd_private();
484 pr->hostname = dupstr(desthost);
489 pr->throttled = pr->throttle_override = 0;
491 pr->backhandle = backhandle;
493 pr->s = s = new_listener(srcaddr, port, (Plug) pr,
494 !conf_get_int(conf, CONF_lport_acceptall),
495 conf, address_family);
496 if ((err = sk_socket_error(s)) != NULL) {
497 free_portfwd_private(pr);
501 sk_set_private_ptr(s, pr);
503 *sockdata = (void *)s;
508 void pfd_close(Socket s)
510 struct PFwdPrivate *pr;
515 pr = (struct PFwdPrivate *) sk_get_private_ptr(s);
517 free_portfwd_private(pr);
523 * Terminate a listener.
525 void pfd_terminate(void *sv)
527 pfd_close((Socket)sv);
530 void pfd_unthrottle(Socket s)
532 struct PFwdPrivate *pr;
535 pr = (struct PFwdPrivate *) sk_get_private_ptr(s);
538 sk_set_frozen(s, pr->throttled || pr->throttle_override);
541 void pfd_override_throttle(Socket s, int enable)
543 struct PFwdPrivate *pr;
546 pr = (struct PFwdPrivate *) sk_get_private_ptr(s);
548 pr->throttle_override = enable;
549 sk_set_frozen(s, pr->throttled || pr->throttle_override);
553 * Called to send data down the raw connection.
555 int pfd_send(Socket s, char *data, int len)
559 return sk_write(s, data, len);
562 void pfd_send_eof(Socket s)
567 void pfd_confirm(Socket s)
569 struct PFwdPrivate *pr;
574 pr = (struct PFwdPrivate *) sk_get_private_ptr(s);
577 sk_write(s, NULL, 0);
579 sshfwd_write(pr->c, pr->buffer, pr->buflen);