14 #define GET_32BIT_LSB_FIRST(cp) \
15 (((unsigned long)(unsigned char)(cp)[0]) | \
16 ((unsigned long)(unsigned char)(cp)[1] << 8) | \
17 ((unsigned long)(unsigned char)(cp)[2] << 16) | \
18 ((unsigned long)(unsigned char)(cp)[3] << 24))
20 #define PUT_32BIT_LSB_FIRST(cp, value) ( \
22 (cp)[1] = (value) >> 8, \
23 (cp)[2] = (value) >> 16, \
24 (cp)[3] = (value) >> 24 )
26 #define GET_16BIT_LSB_FIRST(cp) \
27 (((unsigned long)(unsigned char)(cp)[0]) | \
28 ((unsigned long)(unsigned char)(cp)[1] << 8))
30 #define PUT_16BIT_LSB_FIRST(cp, value) ( \
32 (cp)[1] = (value) >> 8 )
34 #define GET_32BIT_MSB_FIRST(cp) \
35 (((unsigned long)(unsigned char)(cp)[0] << 24) | \
36 ((unsigned long)(unsigned char)(cp)[1] << 16) | \
37 ((unsigned long)(unsigned char)(cp)[2] << 8) | \
38 ((unsigned long)(unsigned char)(cp)[3]))
40 #define PUT_32BIT_MSB_FIRST(cp, value) ( \
41 (cp)[0] = (value) >> 24, \
42 (cp)[1] = (value) >> 16, \
43 (cp)[2] = (value) >> 8, \
46 #define GET_16BIT_MSB_FIRST(cp) \
47 (((unsigned long)(unsigned char)(cp)[0] << 8) | \
48 ((unsigned long)(unsigned char)(cp)[1]))
50 #define PUT_16BIT_MSB_FIRST(cp, value) ( \
51 (cp)[0] = (value) >> 8, \
55 const struct plug_function_table
*fn
;
56 /* the above variable absolutely *must* be the first in this structure */
57 void *c
; /* (channel) data used by ssh.c */
58 void *backhandle
; /* instance of SSH backend itself */
59 /* Note that backhandle need not be filled in if c is non-NULL */
61 int throttled
, throttle_override
;
64 * `dynamic' does double duty. It's set to 0 for an ordinary
65 * forwarded port, and nonzero for SOCKS-style dynamic port
66 * forwarding; but it also represents the state of the SOCKS
71 * `hostname' and `port' are the real hostname and port, once
72 * we know what we're connecting to; they're unused for this
73 * purpose while conducting a local SOCKS exchange, which means
74 * we can also use them as a buffer and pointer for reading
75 * data from the SOCKS client.
80 * When doing dynamic port forwarding, we can receive
81 * connection data before we are actually able to send it; so
82 * we may have to temporarily hold some in a dynamically
83 * allocated buffer here.
89 static int pfd_closing(Plug plug
, const char *error_msg
, int error_code
,
92 struct PFwdPrivate
*pr
= (struct PFwdPrivate
*) plug
;
95 * We have no way to communicate down the forwarded connection,
96 * so if an error occurred on the socket, we just ignore it
97 * and treat it like a proper close.
105 static int pfd_receive(Plug plug
, int urgent
, char *data
, int len
)
107 struct PFwdPrivate
*pr
= (struct PFwdPrivate
*) plug
;
110 if (pr
->port
>= lenof(pr
->hostname
)) {
111 if ((pr
->dynamic
>> 12) == 4) {
112 /* Send back a SOCKS 4 error before closing. */
114 memset(data
, 0, sizeof(data
));
115 data
[1] = 91; /* generic `request rejected' */
116 sk_write(pr
->s
, data
, 8);
121 pr
->hostname
[pr
->port
++] = *data
++;
124 * Now check what's in the buffer to see if it's a
125 * valid and complete message in the SOCKS exchange.
127 if ((pr
->dynamic
== 1 || (pr
->dynamic
>> 12) == 4) &&
128 pr
->hostname
[0] == 4) {
132 if (pr
->dynamic
== 1)
133 pr
->dynamic
= 0x4000;
134 if (pr
->port
< 2) continue;/* don't have command code yet */
135 if (pr
->hostname
[1] != 1) {
136 /* Send back a SOCKS 4 error before closing. */
138 memset(data
, 0, sizeof(data
));
139 data
[1] = 91; /* generic `request rejected' */
140 sk_write(pr
->s
, data
, 8);
144 if (pr
->port
< 8) continue; /* haven't started username */
145 if (pr
->hostname
[pr
->port
-1] != 0)
146 continue; /* haven't _finished_ username */
148 * Now we have a full SOCKS 4 request. Check it to
149 * see if it's a SOCKS 4A request.
151 if (pr
->hostname
[4] == 0 && pr
->hostname
[5] == 0 &&
152 pr
->hostname
[6] == 0 && pr
->hostname
[7] != 0) {
154 * It's SOCKS 4A. So if we haven't yet
155 * collected the host name, we should continue
156 * waiting for data in order to do so; if we
157 * have, we can go ahead.
160 if (pr
->dynamic
== 0x4000) {
161 pr
->dynamic
= 0x4001;
162 pr
->port
= 8; /* reset buffer to overwrite name */
165 pr
->hostname
[0] = 0; /* reply version code */
166 pr
->hostname
[1] = 90; /* request granted */
167 sk_write(pr
->s
, pr
->hostname
, 8);
169 pr
->port
= GET_16BIT_MSB_FIRST(pr
->hostname
+2);
170 memmove(pr
->hostname
, pr
->hostname
+ 8, len
);
174 * It's SOCKS 4, which means we should format
175 * the IP address into the hostname string and
178 pr
->hostname
[0] = 0; /* reply version code */
179 pr
->hostname
[1] = 90; /* request granted */
180 sk_write(pr
->s
, pr
->hostname
, 8);
181 pr
->port
= GET_16BIT_MSB_FIRST(pr
->hostname
+2);
182 sprintf(pr
->hostname
, "%d.%d.%d.%d",
183 (unsigned char)pr
->hostname
[4],
184 (unsigned char)pr
->hostname
[5],
185 (unsigned char)pr
->hostname
[6],
186 (unsigned char)pr
->hostname
[7]);
191 if ((pr
->dynamic
== 1 || (pr
->dynamic
>> 12) == 5) &&
192 pr
->hostname
[0] == 5) {
196 if (pr
->dynamic
== 1)
197 pr
->dynamic
= 0x5000;
199 if (pr
->dynamic
== 0x5000) {
203 * We're receiving a set of method identifiers.
205 if (pr
->port
< 2) continue;/* no method count yet */
206 if (pr
->port
< 2 + (unsigned char)pr
->hostname
[1])
207 continue; /* no methods yet */
208 method
= 0xFF; /* invalid */
209 for (i
= 0; i
< (unsigned char)pr
->hostname
[1]; i
++)
210 if (pr
->hostname
[2+i
] == 0) {
211 method
= 0;/* no auth */
216 sk_write(pr
->s
, data
, 2);
217 pr
->dynamic
= 0x5001;
218 pr
->port
= 0; /* re-empty the buffer */
222 if (pr
->dynamic
== 0x5001) {
224 if (pr
->port
< 6) continue;
225 atype
= (unsigned char)pr
->hostname
[3];
226 if (atype
== 1) /* IPv4 address */
228 if (atype
== 4) /* IPv6 address */
230 if (atype
== 3) /* domain name has leading length */
231 alen
= 1 + (unsigned char)pr
->hostname
[4];
232 if (pr
->port
< 6 + alen
) continue;
233 if (pr
->hostname
[1] != 1 || pr
->hostname
[2] != 0) {
234 pr
->hostname
[1] = 1; /* generic failure */
235 pr
->hostname
[2] = 0; /* reserved */
236 sk_write(pr
->s
, pr
->hostname
, pr
->port
);
241 * Now we have a viable connect request. Switch
244 pr
->port
= GET_16BIT_MSB_FIRST(pr
->hostname
+4+alen
);
246 pr
->hostname
[1] = 0; /* succeeded */
247 sk_write(pr
->s
, pr
->hostname
, alen
+ 6);
248 sprintf(pr
->hostname
, "%d.%d.%d.%d",
249 (unsigned char)pr
->hostname
[4],
250 (unsigned char)pr
->hostname
[5],
251 (unsigned char)pr
->hostname
[6],
252 (unsigned char)pr
->hostname
[7]);
254 } else if (atype
== 3) {
255 pr
->hostname
[1] = 0; /* succeeded */
256 sk_write(pr
->s
, pr
->hostname
, alen
+ 6);
257 memmove(pr
->hostname
, pr
->hostname
+ 5, alen
-1);
258 pr
->hostname
[alen
-1] = '\0';
262 * Unknown address type. (FIXME: support IPv6!)
264 pr
->hostname
[1] = 8; /* atype not supported */
265 sk_write(pr
->s
, pr
->hostname
, pr
->port
);
273 * If we get here without either having done `continue'
274 * or `goto connect', it must be because there is no
275 * sensible interpretation of what's in our buffer. So
276 * close the connection rudely.
284 * We come here when we're ready to make an actual
289 pr
->c
= new_sock_channel(pr
->backhandle
, pr
->s
);
294 /* asks to forward to the specified host/port for this */
295 ssh_send_port_open(pr
->c
, pr
->hostname
, pr
->port
, "forwarding");
300 * Now freeze the socket until the SSH server confirms the
303 sk_set_frozen(pr
->s
, 1);
305 * If there's any data remaining in our current buffer,
306 * save it to be sent on pfd_confirm().
309 pr
->buffer
= snewn(len
, char);
310 memcpy(pr
->buffer
, data
, len
);
315 if (sshfwd_write(pr
->c
, data
, len
) > 0) {
317 sk_set_frozen(pr
->s
, 1);
323 static void pfd_sent(Plug plug
, int bufsize
)
325 struct PFwdPrivate
*pr
= (struct PFwdPrivate
*) plug
;
328 sshfwd_unthrottle(pr
->c
, bufsize
);
332 * Called when receiving a PORT OPEN from the server
334 const char *pfd_newconnect(Socket
*s
, char *hostname
, int port
,
335 void *c
, const Config
*cfg
)
337 static const struct plug_function_table fn_table
= {
346 char *dummy_realhost
;
347 struct PFwdPrivate
*pr
;
352 addr
= name_lookup(hostname
, port
, &dummy_realhost
, cfg
);
353 if ((err
= sk_addr_error(addr
)) != NULL
) {
361 pr
= snew(struct PFwdPrivate
);
364 pr
->throttled
= pr
->throttle_override
= 0;
367 pr
->backhandle
= NULL
; /* we shouldn't need this */
370 pr
->s
= *s
= new_connection(addr
, dummy_realhost
, port
,
371 0, 1, 0, (Plug
) pr
, cfg
);
372 if ((err
= sk_socket_error(*s
)) != NULL
) {
377 sk_set_private_ptr(*s
, pr
);
382 called when someone connects to the local port
385 static int pfd_accepting(Plug p
, OSSocket sock
)
387 static const struct plug_function_table fn_table
= {
393 struct PFwdPrivate
*pr
, *org
;
397 org
= (struct PFwdPrivate
*)p
;
398 pr
= snew(struct PFwdPrivate
);
403 pr
->backhandle
= org
->backhandle
;
405 pr
->s
= s
= sk_register(sock
, (Plug
) pr
);
406 if ((err
= sk_socket_error(s
)) != NULL
) {
411 sk_set_private_ptr(s
, pr
);
413 pr
->throttled
= pr
->throttle_override
= 0;
418 pr
->port
= 0; /* hostname buffer is so far empty */
419 sk_set_frozen(s
, 0); /* we want to receive SOCKS _now_! */
422 strcpy(pr
->hostname
, org
->hostname
);
423 pr
->port
= org
->port
;
424 pr
->c
= new_sock_channel(org
->backhandle
, s
);
430 /* asks to forward to the specified host/port for this */
431 ssh_send_port_open(pr
->c
, pr
->hostname
, pr
->port
, "forwarding");
439 /* Add a new forwarding from port -> desthost:destport
440 sets up a listener on the local machine on (srcaddr:)port
442 const char *pfd_addforward(char *desthost
, int destport
, char *srcaddr
,
443 int port
, void *backhandle
, const Config
*cfg
)
445 static const struct plug_function_table fn_table
= {
447 pfd_receive
, /* should not happen... */
448 pfd_sent
, /* also should not happen */
453 struct PFwdPrivate
*pr
;
459 pr
= snew(struct PFwdPrivate
);
464 strcpy(pr
->hostname
, desthost
);
469 pr
->throttled
= pr
->throttle_override
= 0;
471 pr
->backhandle
= backhandle
;
473 pr
->s
= s
= new_listener(srcaddr
, port
, (Plug
) pr
,
474 !cfg
->lport_acceptall
, cfg
);
475 if ((err
= sk_socket_error(s
)) != NULL
) {
480 sk_set_private_ptr(s
, pr
);
485 void pfd_close(Socket s
)
487 struct PFwdPrivate
*pr
;
492 pr
= (struct PFwdPrivate
*) sk_get_private_ptr(s
);
500 void pfd_unthrottle(Socket s
)
502 struct PFwdPrivate
*pr
;
505 pr
= (struct PFwdPrivate
*) sk_get_private_ptr(s
);
508 sk_set_frozen(s
, pr
->throttled
|| pr
->throttle_override
);
511 void pfd_override_throttle(Socket s
, int enable
)
513 struct PFwdPrivate
*pr
;
516 pr
= (struct PFwdPrivate
*) sk_get_private_ptr(s
);
518 pr
->throttle_override
= enable
;
519 sk_set_frozen(s
, pr
->throttled
|| pr
->throttle_override
);
523 * Called to send data down the raw connection.
525 int pfd_send(Socket s
, char *data
, int len
)
529 return sk_write(s
, data
, len
);
533 void pfd_confirm(Socket s
)
535 struct PFwdPrivate
*pr
;
540 pr
= (struct PFwdPrivate
*) sk_get_private_ptr(s
);
543 sk_write(s
, NULL
, 0);
545 sshfwd_write(pr
->c
, pr
->buffer
, pr
->buflen
);