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 void pfd_log(Plug plug, int type, SockAddr addr, int port,
90 const char *error_msg, int error_code)
92 /* we have to dump these since we have no interface to logging.c */
95 static int pfd_closing(Plug plug, const char *error_msg, int error_code,
98 struct PFwdPrivate *pr = (struct PFwdPrivate *) plug;
101 * We have no way to communicate down the forwarded connection,
102 * so if an error occurred on the socket, we just ignore it
103 * and treat it like a proper close.
111 static int pfd_receive(Plug plug, int urgent, char *data, int len)
113 struct PFwdPrivate *pr = (struct PFwdPrivate *) plug;
117 * Throughout SOCKS negotiation, "hostname" is re-used as a
118 * random protocol buffer with "port" storing the length.
120 if (pr->port >= lenof(pr->hostname)) {
121 /* Request too long. */
122 if ((pr->dynamic >> 12) == 4) {
123 /* Send back a SOCKS 4 error before closing. */
125 memset(data, 0, sizeof(data));
126 data[1] = 91; /* generic `request rejected' */
127 sk_write(pr->s, data, 8);
132 pr->hostname[pr->port++] = *data++;
135 * Now check what's in the buffer to see if it's a
136 * valid and complete message in the SOCKS exchange.
138 if ((pr->dynamic == 1 || (pr->dynamic >> 12) == 4) &&
139 pr->hostname[0] == 4) {
143 if (pr->dynamic == 1)
144 pr->dynamic = 0x4000;
145 if (pr->port < 2) continue;/* don't have command code yet */
146 if (pr->hostname[1] != 1) {
148 /* Send back a SOCKS 4 error before closing. */
150 memset(data, 0, sizeof(data));
151 data[1] = 91; /* generic `request rejected' */
152 sk_write(pr->s, data, 8);
156 if (pr->port <= 8) continue; /* haven't started user/hostname */
157 if (pr->hostname[pr->port-1] != 0)
158 continue; /* haven't _finished_ user/hostname */
160 * Now we have a full SOCKS 4 request. Check it to
161 * see if it's a SOCKS 4A request.
163 if (pr->hostname[4] == 0 && pr->hostname[5] == 0 &&
164 pr->hostname[6] == 0 && pr->hostname[7] != 0) {
166 * It's SOCKS 4A. So if we haven't yet
167 * collected the host name, we should continue
168 * waiting for data in order to do so; if we
169 * have, we can go ahead.
172 if (pr->dynamic == 0x4000) {
173 pr->dynamic = 0x4001;
174 pr->port = 8; /* reset buffer to overwrite name */
177 pr->hostname[0] = 0; /* reply version code */
178 pr->hostname[1] = 90; /* request granted */
179 sk_write(pr->s, pr->hostname, 8);
181 pr->port = GET_16BIT_MSB_FIRST(pr->hostname+2);
182 memmove(pr->hostname, pr->hostname + 8, len);
186 * It's SOCKS 4, which means we should format
187 * the IP address into the hostname string and
190 pr->hostname[0] = 0; /* reply version code */
191 pr->hostname[1] = 90; /* request granted */
192 sk_write(pr->s, pr->hostname, 8);
193 pr->port = GET_16BIT_MSB_FIRST(pr->hostname+2);
194 sprintf(pr->hostname, "%d.%d.%d.%d",
195 (unsigned char)pr->hostname[4],
196 (unsigned char)pr->hostname[5],
197 (unsigned char)pr->hostname[6],
198 (unsigned char)pr->hostname[7]);
203 if ((pr->dynamic == 1 || (pr->dynamic >> 12) == 5) &&
204 pr->hostname[0] == 5) {
208 if (pr->dynamic == 1)
209 pr->dynamic = 0x5000;
211 if (pr->dynamic == 0x5000) {
215 * We're receiving a set of method identifiers.
217 if (pr->port < 2) continue;/* no method count yet */
218 if (pr->port < 2 + (unsigned char)pr->hostname[1])
219 continue; /* no methods yet */
220 method = 0xFF; /* invalid */
221 for (i = 0; i < (unsigned char)pr->hostname[1]; i++)
222 if (pr->hostname[2+i] == 0) {
223 method = 0;/* no auth */
228 sk_write(pr->s, data, 2);
229 pr->dynamic = 0x5001;
230 pr->port = 0; /* re-empty the buffer */
234 if (pr->dynamic == 0x5001) {
236 * We're receiving a SOCKS request.
238 unsigned char reply[10]; /* SOCKS5 atyp=1 reply */
242 * Pre-fill reply packet.
243 * In all cases, we set BND.{HOST,ADDR} to 0.0.0.0:0
244 * (atyp=1) in the reply; if we succeed, we don't know
245 * the right answers, and if we fail, they should be
248 memset(reply, 0, lenof(reply));
249 reply[0] = 5; /* VER */
250 reply[3] = 1; /* ATYP = 1 (IPv4, 0.0.0.0:0) */
252 if (pr->port < 6) continue;
253 atype = (unsigned char)pr->hostname[3];
254 if (atype == 1) /* IPv4 address */
256 if (atype == 4) /* IPv6 address */
258 if (atype == 3) /* domain name has leading length */
259 alen = 1 + (unsigned char)pr->hostname[4];
260 if (pr->port < 6 + alen) continue;
261 if (pr->hostname[1] != 1 || pr->hostname[2] != 0) {
262 /* Not CONNECT or reserved field nonzero - error */
263 reply[1] = 1; /* generic failure */
264 sk_write(pr->s, (char *) reply, lenof(reply));
269 * Now we have a viable connect request. Switch
272 pr->port = GET_16BIT_MSB_FIRST(pr->hostname+4+alen);
274 /* REP=0 (success) already */
275 sk_write(pr->s, (char *) reply, lenof(reply));
276 sprintf(pr->hostname, "%d.%d.%d.%d",
277 (unsigned char)pr->hostname[4],
278 (unsigned char)pr->hostname[5],
279 (unsigned char)pr->hostname[6],
280 (unsigned char)pr->hostname[7]);
282 } else if (atype == 3) {
283 /* REP=0 (success) already */
284 sk_write(pr->s, (char *) reply, lenof(reply));
285 memmove(pr->hostname, pr->hostname + 5, alen-1);
286 pr->hostname[alen-1] = '\0';
290 * Unknown address type. (FIXME: support IPv6!)
292 reply[1] = 8; /* atype not supported */
293 sk_write(pr->s, (char *) reply, lenof(reply));
301 * If we get here without either having done `continue'
302 * or `goto connect', it must be because there is no
303 * sensible interpretation of what's in our buffer. So
304 * close the connection rudely.
312 * We come here when we're ready to make an actual
317 pr->c = new_sock_channel(pr->backhandle, pr->s);
322 /* asks to forward to the specified host/port for this */
323 ssh_send_port_open(pr->c, pr->hostname, pr->port, "forwarding");
328 * Now freeze the socket until the SSH server confirms the
331 sk_set_frozen(pr->s, 1);
333 * If there's any data remaining in our current buffer,
334 * save it to be sent on pfd_confirm().
337 pr->buffer = snewn(len, char);
338 memcpy(pr->buffer, data, len);
343 if (sshfwd_write(pr->c, data, len) > 0) {
345 sk_set_frozen(pr->s, 1);
351 static void pfd_sent(Plug plug, int bufsize)
353 struct PFwdPrivate *pr = (struct PFwdPrivate *) plug;
356 sshfwd_unthrottle(pr->c, bufsize);
360 * Called when receiving a PORT OPEN from the server
362 const char *pfd_newconnect(Socket *s, char *hostname, int port,
363 void *c, const Config *cfg, int addressfamily)
365 static const struct plug_function_table fn_table = {
375 char *dummy_realhost;
376 struct PFwdPrivate *pr;
381 addr = name_lookup(hostname, port, &dummy_realhost, cfg, addressfamily);
382 if ((err = sk_addr_error(addr)) != NULL) {
390 pr = snew(struct PFwdPrivate);
393 pr->throttled = pr->throttle_override = 0;
396 pr->backhandle = NULL; /* we shouldn't need this */
399 pr->s = *s = new_connection(addr, dummy_realhost, port,
400 0, 1, 0, 0, (Plug) pr, cfg);
401 if ((err = sk_socket_error(*s)) != NULL) {
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 = snew(struct PFwdPrivate);
433 pr->backhandle = org->backhandle;
435 pr->s = s = sk_register(sock, (Plug) pr);
436 if ((err = sk_socket_error(s)) != NULL) {
441 sk_set_private_ptr(s, pr);
443 pr->throttled = pr->throttle_override = 0;
448 pr->port = 0; /* "hostname" buffer is so far empty */
449 sk_set_frozen(s, 0); /* we want to receive SOCKS _now_! */
452 strcpy(pr->hostname, org->hostname);
453 pr->port = org->port;
454 pr->c = new_sock_channel(org->backhandle, s);
460 /* asks to forward to the specified host/port for this */
461 ssh_send_port_open(pr->c, pr->hostname, pr->port, "forwarding");
469 /* Add a new forwarding from port -> desthost:destport
470 sets up a listener on the local machine on (srcaddr:)port
472 const char *pfd_addforward(char *desthost, int destport, char *srcaddr,
473 int port, void *backhandle, const Config *cfg,
474 void **sockdata, int address_family)
476 static const struct plug_function_table fn_table = {
479 pfd_receive, /* should not happen... */
480 pfd_sent, /* also should not happen */
485 struct PFwdPrivate *pr;
491 pr = snew(struct PFwdPrivate);
496 strcpy(pr->hostname, desthost);
501 pr->throttled = pr->throttle_override = 0;
503 pr->backhandle = backhandle;
505 pr->s = s = new_listener(srcaddr, port, (Plug) pr,
506 !cfg->lport_acceptall, cfg, address_family);
507 if ((err = sk_socket_error(s)) != NULL) {
512 sk_set_private_ptr(s, pr);
514 *sockdata = (void *)s;
519 void pfd_close(Socket s)
521 struct PFwdPrivate *pr;
526 pr = (struct PFwdPrivate *) sk_get_private_ptr(s);
535 * Terminate a listener.
537 void pfd_terminate(void *sv)
539 pfd_close((Socket)sv);
542 void pfd_unthrottle(Socket s)
544 struct PFwdPrivate *pr;
547 pr = (struct PFwdPrivate *) sk_get_private_ptr(s);
550 sk_set_frozen(s, pr->throttled || pr->throttle_override);
553 void pfd_override_throttle(Socket s, int enable)
555 struct PFwdPrivate *pr;
558 pr = (struct PFwdPrivate *) sk_get_private_ptr(s);
560 pr->throttle_override = enable;
561 sk_set_frozen(s, pr->throttled || pr->throttle_override);
565 * Called to send data down the raw connection.
567 int pfd_send(Socket s, char *data, int len)
571 return sk_write(s, data, len);
575 void pfd_confirm(Socket s)
577 struct PFwdPrivate *pr;
582 pr = (struct PFwdPrivate *) sk_get_private_ptr(s);
585 sk_write(s, NULL, 0);
587 sshfwd_write(pr->c, pr->buffer, pr->buflen);