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
);