15 const struct plug_function_table
*fn
;
16 /* the above variable absolutely *must* be the first in this structure */
17 void *c
; /* (channel) data used by ssh.c */
18 void *backhandle
; /* instance of SSH backend itself */
19 /* Note that backhandle need not be filled in if c is non-NULL */
21 int throttled
, throttle_override
;
24 * `dynamic' does double duty. It's set to 0 for an ordinary
25 * forwarded port, and nonzero for SOCKS-style dynamic port
26 * forwarding; but it also represents the state of the SOCKS
31 * `hostname' and `port' are the real hostname and port, once
32 * we know what we're connecting to; they're unused for this
33 * purpose while conducting a local SOCKS exchange, which means
34 * we can also use them as a buffer and pointer for reading
35 * data from the SOCKS client.
40 * When doing dynamic port forwarding, we can receive
41 * connection data before we are actually able to send it; so
42 * we may have to temporarily hold some in a dynamically
43 * allocated buffer here.
49 static void pfd_log(Plug plug
, int type
, SockAddr addr
, int port
,
50 const char *error_msg
, int error_code
)
52 /* we have to dump these since we have no interface to logging.c */
55 static int pfd_closing(Plug plug
, const char *error_msg
, int error_code
,
58 struct PFwdPrivate
*pr
= (struct PFwdPrivate
*) plug
;
61 * We have no way to communicate down the forwarded connection,
62 * so if an error occurred on the socket, we just ignore it
63 * and treat it like a proper close.
71 static int pfd_receive(Plug plug
, int urgent
, char *data
, int len
)
73 struct PFwdPrivate
*pr
= (struct PFwdPrivate
*) plug
;
77 * Throughout SOCKS negotiation, "hostname" is re-used as a
78 * random protocol buffer with "port" storing the length.
80 if (pr
->port
>= lenof(pr
->hostname
)) {
81 /* Request too long. */
82 if ((pr
->dynamic
>> 12) == 4) {
83 /* Send back a SOCKS 4 error before closing. */
85 memset(data
, 0, sizeof(data
));
86 data
[1] = 91; /* generic `request rejected' */
87 sk_write(pr
->s
, data
, 8);
92 pr
->hostname
[pr
->port
++] = *data
++;
95 * Now check what's in the buffer to see if it's a
96 * valid and complete message in the SOCKS exchange.
98 if ((pr
->dynamic
== 1 || (pr
->dynamic
>> 12) == 4) &&
99 pr
->hostname
[0] == 4) {
103 if (pr
->dynamic
== 1)
104 pr
->dynamic
= 0x4000;
105 if (pr
->port
< 2) continue;/* don't have command code yet */
106 if (pr
->hostname
[1] != 1) {
108 /* Send back a SOCKS 4 error before closing. */
110 memset(data
, 0, sizeof(data
));
111 data
[1] = 91; /* generic `request rejected' */
112 sk_write(pr
->s
, data
, 8);
116 if (pr
->port
<= 8) continue; /* haven't started user/hostname */
117 if (pr
->hostname
[pr
->port
-1] != 0)
118 continue; /* haven't _finished_ user/hostname */
120 * Now we have a full SOCKS 4 request. Check it to
121 * see if it's a SOCKS 4A request.
123 if (pr
->hostname
[4] == 0 && pr
->hostname
[5] == 0 &&
124 pr
->hostname
[6] == 0 && pr
->hostname
[7] != 0) {
126 * It's SOCKS 4A. So if we haven't yet
127 * collected the host name, we should continue
128 * waiting for data in order to do so; if we
129 * have, we can go ahead.
132 if (pr
->dynamic
== 0x4000) {
133 pr
->dynamic
= 0x4001;
134 pr
->port
= 8; /* reset buffer to overwrite name */
137 pr
->hostname
[0] = 0; /* reply version code */
138 pr
->hostname
[1] = 90; /* request granted */
139 sk_write(pr
->s
, pr
->hostname
, 8);
141 pr
->port
= GET_16BIT_MSB_FIRST(pr
->hostname
+2);
142 memmove(pr
->hostname
, pr
->hostname
+ 8, len
);
146 * It's SOCKS 4, which means we should format
147 * the IP address into the hostname string and
150 pr
->hostname
[0] = 0; /* reply version code */
151 pr
->hostname
[1] = 90; /* request granted */
152 sk_write(pr
->s
, pr
->hostname
, 8);
153 pr
->port
= GET_16BIT_MSB_FIRST(pr
->hostname
+2);
154 sprintf(pr
->hostname
, "%d.%d.%d.%d",
155 (unsigned char)pr
->hostname
[4],
156 (unsigned char)pr
->hostname
[5],
157 (unsigned char)pr
->hostname
[6],
158 (unsigned char)pr
->hostname
[7]);
163 if ((pr
->dynamic
== 1 || (pr
->dynamic
>> 12) == 5) &&
164 pr
->hostname
[0] == 5) {
168 if (pr
->dynamic
== 1)
169 pr
->dynamic
= 0x5000;
171 if (pr
->dynamic
== 0x5000) {
175 * We're receiving a set of method identifiers.
177 if (pr
->port
< 2) continue;/* no method count yet */
178 if (pr
->port
< 2 + (unsigned char)pr
->hostname
[1])
179 continue; /* no methods yet */
180 method
= 0xFF; /* invalid */
181 for (i
= 0; i
< (unsigned char)pr
->hostname
[1]; i
++)
182 if (pr
->hostname
[2+i
] == 0) {
183 method
= 0;/* no auth */
188 sk_write(pr
->s
, data
, 2);
189 pr
->dynamic
= 0x5001;
190 pr
->port
= 0; /* re-empty the buffer */
194 if (pr
->dynamic
== 0x5001) {
196 * We're receiving a SOCKS request.
198 unsigned char reply
[10]; /* SOCKS5 atyp=1 reply */
202 * Pre-fill reply packet.
203 * In all cases, we set BND.{HOST,ADDR} to 0.0.0.0:0
204 * (atyp=1) in the reply; if we succeed, we don't know
205 * the right answers, and if we fail, they should be
208 memset(reply
, 0, lenof(reply
));
209 reply
[0] = 5; /* VER */
210 reply
[3] = 1; /* ATYP = 1 (IPv4, 0.0.0.0:0) */
212 if (pr
->port
< 6) continue;
213 atype
= (unsigned char)pr
->hostname
[3];
214 if (atype
== 1) /* IPv4 address */
216 if (atype
== 4) /* IPv6 address */
218 if (atype
== 3) /* domain name has leading length */
219 alen
= 1 + (unsigned char)pr
->hostname
[4];
220 if (pr
->port
< 6 + alen
) continue;
221 if (pr
->hostname
[1] != 1 || pr
->hostname
[2] != 0) {
222 /* Not CONNECT or reserved field nonzero - error */
223 reply
[1] = 1; /* generic failure */
224 sk_write(pr
->s
, (char *) reply
, lenof(reply
));
229 * Now we have a viable connect request. Switch
232 pr
->port
= GET_16BIT_MSB_FIRST(pr
->hostname
+4+alen
);
234 /* REP=0 (success) already */
235 sk_write(pr
->s
, (char *) reply
, lenof(reply
));
236 sprintf(pr
->hostname
, "%d.%d.%d.%d",
237 (unsigned char)pr
->hostname
[4],
238 (unsigned char)pr
->hostname
[5],
239 (unsigned char)pr
->hostname
[6],
240 (unsigned char)pr
->hostname
[7]);
242 } else if (atype
== 3) {
243 /* REP=0 (success) already */
244 sk_write(pr
->s
, (char *) reply
, lenof(reply
));
245 memmove(pr
->hostname
, pr
->hostname
+ 5, alen
-1);
246 pr
->hostname
[alen
-1] = '\0';
250 * Unknown address type. (FIXME: support IPv6!)
252 reply
[1] = 8; /* atype not supported */
253 sk_write(pr
->s
, (char *) reply
, lenof(reply
));
261 * If we get here without either having done `continue'
262 * or `goto connect', it must be because there is no
263 * sensible interpretation of what's in our buffer. So
264 * close the connection rudely.
272 * We come here when we're ready to make an actual
277 pr
->c
= new_sock_channel(pr
->backhandle
, pr
->s
);
282 /* asks to forward to the specified host/port for this */
283 ssh_send_port_open(pr
->c
, pr
->hostname
, pr
->port
, "forwarding");
288 * Now freeze the socket until the SSH server confirms the
291 sk_set_frozen(pr
->s
, 1);
293 * If there's any data remaining in our current buffer,
294 * save it to be sent on pfd_confirm().
297 pr
->buffer
= snewn(len
, char);
298 memcpy(pr
->buffer
, data
, len
);
303 if (sshfwd_write(pr
->c
, data
, len
) > 0) {
305 sk_set_frozen(pr
->s
, 1);
311 static void pfd_sent(Plug plug
, int bufsize
)
313 struct PFwdPrivate
*pr
= (struct PFwdPrivate
*) plug
;
316 sshfwd_unthrottle(pr
->c
, bufsize
);
320 * Called when receiving a PORT OPEN from the server
322 const char *pfd_newconnect(Socket
*s
, char *hostname
, int port
,
323 void *c
, const Config
*cfg
, int addressfamily
)
325 static const struct plug_function_table fn_table
= {
335 char *dummy_realhost
;
336 struct PFwdPrivate
*pr
;
341 addr
= name_lookup(hostname
, port
, &dummy_realhost
, cfg
, addressfamily
);
342 if ((err
= sk_addr_error(addr
)) != NULL
) {
350 pr
= snew(struct PFwdPrivate
);
353 pr
->throttled
= pr
->throttle_override
= 0;
356 pr
->backhandle
= NULL
; /* we shouldn't need this */
359 pr
->s
= *s
= new_connection(addr
, dummy_realhost
, port
,
360 0, 1, 0, 0, (Plug
) pr
, cfg
);
361 if ((err
= sk_socket_error(*s
)) != NULL
) {
366 sk_set_private_ptr(*s
, pr
);
371 called when someone connects to the local port
374 static int pfd_accepting(Plug p
, OSSocket sock
)
376 static const struct plug_function_table fn_table
= {
383 struct PFwdPrivate
*pr
, *org
;
387 org
= (struct PFwdPrivate
*)p
;
388 pr
= snew(struct PFwdPrivate
);
393 pr
->backhandle
= org
->backhandle
;
395 pr
->s
= s
= sk_register(sock
, (Plug
) pr
);
396 if ((err
= sk_socket_error(s
)) != NULL
) {
401 sk_set_private_ptr(s
, pr
);
403 pr
->throttled
= pr
->throttle_override
= 0;
408 pr
->port
= 0; /* "hostname" buffer is so far empty */
409 sk_set_frozen(s
, 0); /* we want to receive SOCKS _now_! */
412 strcpy(pr
->hostname
, org
->hostname
);
413 pr
->port
= org
->port
;
414 pr
->c
= new_sock_channel(org
->backhandle
, s
);
420 /* asks to forward to the specified host/port for this */
421 ssh_send_port_open(pr
->c
, pr
->hostname
, pr
->port
, "forwarding");
429 /* Add a new forwarding from port -> desthost:destport
430 sets up a listener on the local machine on (srcaddr:)port
432 const char *pfd_addforward(char *desthost
, int destport
, char *srcaddr
,
433 int port
, void *backhandle
, const Config
*cfg
,
434 void **sockdata
, int address_family
)
436 static const struct plug_function_table fn_table
= {
439 pfd_receive
, /* should not happen... */
440 pfd_sent
, /* also should not happen */
445 struct PFwdPrivate
*pr
;
451 pr
= snew(struct PFwdPrivate
);
456 strcpy(pr
->hostname
, desthost
);
461 pr
->throttled
= pr
->throttle_override
= 0;
463 pr
->backhandle
= backhandle
;
465 pr
->s
= s
= new_listener(srcaddr
, port
, (Plug
) pr
,
466 !cfg
->lport_acceptall
, cfg
, address_family
);
467 if ((err
= sk_socket_error(s
)) != NULL
) {
472 sk_set_private_ptr(s
, pr
);
474 *sockdata
= (void *)s
;
479 void pfd_close(Socket s
)
481 struct PFwdPrivate
*pr
;
486 pr
= (struct PFwdPrivate
*) sk_get_private_ptr(s
);
495 * Terminate a listener.
497 void pfd_terminate(void *sv
)
499 pfd_close((Socket
)sv
);
502 void pfd_unthrottle(Socket s
)
504 struct PFwdPrivate
*pr
;
507 pr
= (struct PFwdPrivate
*) sk_get_private_ptr(s
);
510 sk_set_frozen(s
, pr
->throttled
|| pr
->throttle_override
);
513 void pfd_override_throttle(Socket s
, int enable
)
515 struct PFwdPrivate
*pr
;
518 pr
= (struct PFwdPrivate
*) sk_get_private_ptr(s
);
520 pr
->throttle_override
= enable
;
521 sk_set_frozen(s
, pr
->throttled
|| pr
->throttle_override
);
525 * Called to send data down the raw connection.
527 int pfd_send(Socket s
, char *data
, int len
)
531 return sk_write(s
, data
, len
);
535 void pfd_confirm(Socket s
)
537 struct PFwdPrivate
*pr
;
542 pr
= (struct PFwdPrivate
*) sk_get_private_ptr(s
);
545 sk_write(s
, NULL
, 0);
547 sshfwd_write(pr
->c
, pr
->buffer
, pr
->buflen
);