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.
91 sshfwd_unclean_close(pr
->c
);
94 * We might not have an SSH channel, if a socket error
95 * occurred during SOCKS negotiation. If not, we must
96 * clean ourself up without sshfwd_unclean_close's call
103 * Ordinary EOF received on socket. Send an EOF on the SSH
107 sshfwd_write_eof(pr
->c
);
113 static int pfd_receive(Plug plug
, int urgent
, char *data
, int len
)
115 struct PFwdPrivate
*pr
= (struct PFwdPrivate
*) plug
;
118 if (pr
->sockslen
>= pr
->sockssize
) {
119 pr
->sockssize
= pr
->sockslen
* 5 / 4 + 256;
120 pr
->socksbuf
= sresize(pr
->socksbuf
, pr
->sockssize
, char);
122 pr
->socksbuf
[pr
->sockslen
++] = *data
++;
125 * Now check what's in the buffer to see if it's a
126 * valid and complete message in the SOCKS exchange.
128 if ((pr
->dynamic
== 1 || (pr
->dynamic
>> 12) == 4) &&
129 pr
->socksbuf
[0] == 4) {
133 if (pr
->dynamic
== 1)
134 pr
->dynamic
= 0x4000;
135 if (pr
->sockslen
< 2)
136 continue; /* don't have command code yet */
137 if (pr
->socksbuf
[1] != 1) {
139 /* Send back a SOCKS 4 error before closing. */
141 memset(data
, 0, sizeof(data
));
142 data
[1] = 91; /* generic `request rejected' */
143 sk_write(pr
->s
, data
, 8);
147 if (pr
->sockslen
<= 8)
148 continue; /* haven't started user/hostname */
149 if (pr
->socksbuf
[pr
->sockslen
-1] != 0)
150 continue; /* haven't _finished_ user/hostname */
152 * Now we have a full SOCKS 4 request. Check it to
153 * see if it's a SOCKS 4A request.
155 if (pr
->socksbuf
[4] == 0 && pr
->socksbuf
[5] == 0 &&
156 pr
->socksbuf
[6] == 0 && pr
->socksbuf
[7] != 0) {
158 * It's SOCKS 4A. So if we haven't yet
159 * collected the host name, we should continue
160 * waiting for data in order to do so; if we
161 * have, we can go ahead.
164 if (pr
->dynamic
== 0x4000) {
165 pr
->dynamic
= 0x4001;
166 pr
->sockslen
= 8; /* reset buffer to overwrite name */
169 pr
->socksbuf
[0] = 0; /* reply version code */
170 pr
->socksbuf
[1] = 90; /* request granted */
171 sk_write(pr
->s
, pr
->socksbuf
, 8);
172 len
= pr
->sockslen
- 8;
173 pr
->port
= GET_16BIT_MSB_FIRST(pr
->socksbuf
+2);
174 pr
->hostname
= snewn(len
+1, char);
175 pr
->hostname
[len
] = '\0';
176 memcpy(pr
->hostname
, pr
->socksbuf
+ 8, len
);
180 * It's SOCKS 4, which means we should format
181 * the IP address into the hostname string and
184 pr
->socksbuf
[0] = 0; /* reply version code */
185 pr
->socksbuf
[1] = 90; /* request granted */
186 sk_write(pr
->s
, pr
->socksbuf
, 8);
187 pr
->port
= GET_16BIT_MSB_FIRST(pr
->socksbuf
+2);
188 pr
->hostname
= dupprintf("%d.%d.%d.%d",
189 (unsigned char)pr
->socksbuf
[4],
190 (unsigned char)pr
->socksbuf
[5],
191 (unsigned char)pr
->socksbuf
[6],
192 (unsigned char)pr
->socksbuf
[7]);
197 if ((pr
->dynamic
== 1 || (pr
->dynamic
>> 12) == 5) &&
198 pr
->socksbuf
[0] == 5) {
202 if (pr
->dynamic
== 1)
203 pr
->dynamic
= 0x5000;
205 if (pr
->dynamic
== 0x5000) {
209 * We're receiving a set of method identifiers.
211 if (pr
->sockslen
< 2)
212 continue; /* no method count yet */
213 if (pr
->sockslen
< 2 + (unsigned char)pr
->socksbuf
[1])
214 continue; /* no methods yet */
215 method
= 0xFF; /* invalid */
216 for (i
= 0; i
< (unsigned char)pr
->socksbuf
[1]; i
++)
217 if (pr
->socksbuf
[2+i
] == 0) {
218 method
= 0;/* no auth */
223 sk_write(pr
->s
, data
, 2);
224 pr
->dynamic
= 0x5001;
225 pr
->sockslen
= 0; /* re-empty the buffer */
229 if (pr
->dynamic
== 0x5001) {
231 * We're receiving a SOCKS request.
233 unsigned char reply
[10]; /* SOCKS5 atyp=1 reply */
237 * Pre-fill reply packet.
238 * In all cases, we set BND.{HOST,ADDR} to 0.0.0.0:0
239 * (atyp=1) in the reply; if we succeed, we don't know
240 * the right answers, and if we fail, they should be
243 memset(reply
, 0, lenof(reply
));
244 reply
[0] = 5; /* VER */
245 reply
[3] = 1; /* ATYP = 1 (IPv4, 0.0.0.0:0) */
247 if (pr
->sockslen
< 6) continue;
248 atype
= (unsigned char)pr
->socksbuf
[3];
249 if (atype
== 1) /* IPv4 address */
251 if (atype
== 4) /* IPv6 address */
253 if (atype
== 3) /* domain name has leading length */
254 alen
= 1 + (unsigned char)pr
->socksbuf
[4];
255 if (pr
->sockslen
< 6 + alen
) continue;
256 if (pr
->socksbuf
[1] != 1 || pr
->socksbuf
[2] != 0) {
257 /* Not CONNECT or reserved field nonzero - error */
258 reply
[1] = 1; /* generic failure */
259 sk_write(pr
->s
, (char *) reply
, lenof(reply
));
264 * Now we have a viable connect request. Switch
267 pr
->port
= GET_16BIT_MSB_FIRST(pr
->socksbuf
+4+alen
);
269 /* REP=0 (success) already */
270 sk_write(pr
->s
, (char *) reply
, lenof(reply
));
271 pr
->hostname
= dupprintf("%d.%d.%d.%d",
272 (unsigned char)pr
->socksbuf
[4],
273 (unsigned char)pr
->socksbuf
[5],
274 (unsigned char)pr
->socksbuf
[6],
275 (unsigned char)pr
->socksbuf
[7]);
277 } else if (atype
== 3) {
278 /* REP=0 (success) already */
279 sk_write(pr
->s
, (char *) reply
, lenof(reply
));
280 pr
->hostname
= snewn(alen
, char);
281 pr
->hostname
[alen
-1] = '\0';
282 memcpy(pr
->hostname
, pr
->socksbuf
+ 5, alen
-1);
286 * Unknown address type. (FIXME: support IPv6!)
288 reply
[1] = 8; /* atype not supported */
289 sk_write(pr
->s
, (char *) reply
, lenof(reply
));
297 * If we get here without either having done `continue'
298 * or `goto connect', it must be because there is no
299 * sensible interpretation of what's in our buffer. So
300 * close the connection rudely.
308 * We come here when we're ready to make an actual
316 * Freeze the socket until the SSH server confirms the
319 sk_set_frozen(pr
->s
, 1);
321 pr
->c
= new_sock_channel(pr
->backhandle
, pr
->s
);
326 /* asks to forward to the specified host/port for this */
327 ssh_send_port_open(pr
->c
, pr
->hostname
, pr
->port
, "forwarding");
332 * If there's any data remaining in our current buffer,
333 * save it to be sent on pfd_confirm().
336 pr
->buffer
= snewn(len
, char);
337 memcpy(pr
->buffer
, data
, len
);
342 if (sshfwd_write(pr
->c
, data
, len
) > 0) {
344 sk_set_frozen(pr
->s
, 1);
350 static void pfd_sent(Plug plug
, int bufsize
)
352 struct PFwdPrivate
*pr
= (struct PFwdPrivate
*) plug
;
355 sshfwd_unthrottle(pr
->c
, bufsize
);
359 * Called when receiving a PORT OPEN from the server
361 const char *pfd_newconnect(Socket
*s
, char *hostname
, int port
,
362 void *c
, Conf
*conf
, int addressfamily
)
364 static const struct plug_function_table fn_table
= {
374 char *dummy_realhost
;
375 struct PFwdPrivate
*pr
;
380 addr
= name_lookup(hostname
, port
, &dummy_realhost
, conf
, addressfamily
);
381 if ((err
= sk_addr_error(addr
)) != NULL
) {
383 sfree(dummy_realhost
);
390 pr
= new_portfwd_private();
392 pr
->throttled
= pr
->throttle_override
= 0;
395 pr
->backhandle
= NULL
; /* we shouldn't need this */
398 pr
->s
= *s
= new_connection(addr
, dummy_realhost
, port
,
399 0, 1, 0, 0, (Plug
) pr
, conf
);
400 sfree(dummy_realhost
);
401 if ((err
= sk_socket_error(*s
)) != NULL
) {
402 free_portfwd_private(pr
);
406 sk_set_private_ptr(*s
, pr
);
411 called when someone connects to the local port
414 static int pfd_accepting(Plug p
, OSSocket sock
)
416 static const struct plug_function_table fn_table
= {
423 struct PFwdPrivate
*pr
, *org
;
427 org
= (struct PFwdPrivate
*)p
;
428 pr
= new_portfwd_private();
432 pr
->backhandle
= org
->backhandle
;
434 pr
->s
= s
= sk_register(sock
, (Plug
) pr
);
435 if ((err
= sk_socket_error(s
)) != NULL
) {
436 free_portfwd_private(pr
);
440 sk_set_private_ptr(s
, pr
);
442 pr
->throttled
= pr
->throttle_override
= 0;
447 pr
->port
= 0; /* "hostname" buffer is so far empty */
448 sk_set_frozen(s
, 0); /* we want to receive SOCKS _now_! */
451 pr
->hostname
= dupstr(org
->hostname
);
452 pr
->port
= org
->port
;
453 pr
->c
= new_sock_channel(org
->backhandle
, s
);
456 free_portfwd_private(pr
);
459 /* asks to forward to the specified host/port for this */
460 ssh_send_port_open(pr
->c
, pr
->hostname
, pr
->port
, "forwarding");
468 /* Add a new forwarding from port -> desthost:destport
469 sets up a listener on the local machine on (srcaddr:)port
471 const char *pfd_addforward(char *desthost
, int destport
, char *srcaddr
,
472 int port
, void *backhandle
, Conf
*conf
,
473 void **sockdata
, int address_family
)
475 static const struct plug_function_table fn_table
= {
478 pfd_receive
, /* should not happen... */
479 pfd_sent
, /* also should not happen */
484 struct PFwdPrivate
*pr
;
490 pr
= new_portfwd_private();
494 pr
->hostname
= dupstr(desthost
);
499 pr
->throttled
= pr
->throttle_override
= 0;
501 pr
->backhandle
= backhandle
;
503 pr
->s
= s
= new_listener(srcaddr
, port
, (Plug
) pr
,
504 !conf_get_int(conf
, CONF_lport_acceptall
),
505 conf
, address_family
);
506 if ((err
= sk_socket_error(s
)) != NULL
) {
507 free_portfwd_private(pr
);
511 sk_set_private_ptr(s
, pr
);
513 *sockdata
= (void *)s
;
518 void pfd_close(Socket s
)
520 struct PFwdPrivate
*pr
;
525 pr
= (struct PFwdPrivate
*) sk_get_private_ptr(s
);
527 free_portfwd_private(pr
);
533 * Terminate a listener.
535 void pfd_terminate(void *sv
)
537 pfd_close((Socket
)sv
);
540 void pfd_unthrottle(Socket s
)
542 struct PFwdPrivate
*pr
;
545 pr
= (struct PFwdPrivate
*) sk_get_private_ptr(s
);
548 sk_set_frozen(s
, pr
->throttled
|| pr
->throttle_override
);
551 void pfd_override_throttle(Socket s
, int enable
)
553 struct PFwdPrivate
*pr
;
556 pr
= (struct PFwdPrivate
*) sk_get_private_ptr(s
);
558 pr
->throttle_override
= enable
;
559 sk_set_frozen(s
, pr
->throttled
|| pr
->throttle_override
);
563 * Called to send data down the raw connection.
565 int pfd_send(Socket s
, char *data
, int len
)
569 return sk_write(s
, data
, len
);
572 void pfd_send_eof(Socket s
)
577 void pfd_confirm(Socket s
)
579 struct PFwdPrivate
*pr
;
584 pr
= (struct PFwdPrivate
*) sk_get_private_ptr(s
);
587 sk_write(s
, NULL
, 0);
589 sshfwd_write(pr
->c
, pr
->buffer
, pr
->buflen
);