| 1 | /* |
| 2 | * Network proxy abstraction in PuTTY |
| 3 | * |
| 4 | * A proxy layer, if necessary, wedges itself between the network |
| 5 | * code and the higher level backend. |
| 6 | */ |
| 7 | |
| 8 | #include <windows.h> |
| 9 | |
| 10 | #define DEFINE_PLUG_METHOD_MACROS |
| 11 | #include "putty.h" |
| 12 | #include "network.h" |
| 13 | #include "proxy.h" |
| 14 | |
| 15 | /* |
| 16 | * Call this when proxy negotiation is complete, so that this |
| 17 | * socket can begin working normally. |
| 18 | */ |
| 19 | void proxy_activate (Proxy_Socket p) |
| 20 | { |
| 21 | void *data; |
| 22 | int len; |
| 23 | |
| 24 | p->lock_close = |
| 25 | p->lock_write = |
| 26 | p->lock_write_oob = |
| 27 | p->lock_receive = |
| 28 | p->lock_flush = |
| 29 | p->lock_closing = |
| 30 | p->lock_sent = |
| 31 | p->lock_accepting = |
| 32 | p->lock_freeze = 1; |
| 33 | |
| 34 | p->state = PROXY_STATE_ACTIVE; |
| 35 | |
| 36 | /* let's try to keep extra receive events from coming through */ |
| 37 | sk_set_frozen(p->sub_socket, 1); |
| 38 | |
| 39 | while (bufchain_size(&p->pending_oob_output_data) > 0) { |
| 40 | bufchain_prefix(&p->pending_oob_output_data, &data, &len); |
| 41 | sk_write_oob(p->sub_socket, data, len); |
| 42 | bufchain_consume(&p->pending_oob_output_data, len); |
| 43 | } |
| 44 | bufchain_clear(&p->pending_oob_output_data); |
| 45 | |
| 46 | while (bufchain_size(&p->pending_output_data) > 0) { |
| 47 | bufchain_prefix(&p->pending_output_data, &data, &len); |
| 48 | sk_write(p->sub_socket, data, len); |
| 49 | bufchain_consume(&p->pending_output_data, len); |
| 50 | } |
| 51 | bufchain_clear(&p->pending_output_data); |
| 52 | |
| 53 | p->lock_write_oob = 0; |
| 54 | p->lock_write = 0; |
| 55 | |
| 56 | if (p->pending_flush) sk_flush(p->sub_socket); |
| 57 | p->lock_flush = 0; |
| 58 | |
| 59 | while (bufchain_size(&p->pending_input_data) > 0) { |
| 60 | bufchain_prefix(&p->pending_input_data, &data, &len); |
| 61 | plug_receive(p->plug, 0, data, len); |
| 62 | bufchain_consume(&p->pending_input_data, len); |
| 63 | } |
| 64 | bufchain_clear(&p->pending_input_data); |
| 65 | p->lock_receive = 0; |
| 66 | |
| 67 | /* now set the underlying socket to whatever freeze state they wanted */ |
| 68 | sk_set_frozen(p->sub_socket, p->freeze); |
| 69 | p->lock_freeze = 0; |
| 70 | |
| 71 | p->lock_sent = 0; |
| 72 | p->lock_accepting = 0; |
| 73 | p->lock_closing = 0; |
| 74 | p->lock_close = 0; |
| 75 | } |
| 76 | |
| 77 | /* basic proxy socket functions */ |
| 78 | |
| 79 | static Plug sk_proxy_plug (Socket s, Plug p) |
| 80 | { |
| 81 | Proxy_Socket ps = (Proxy_Socket) s; |
| 82 | Plug ret = ps->plug; |
| 83 | if (p) |
| 84 | ps->plug = p; |
| 85 | return ret; |
| 86 | } |
| 87 | |
| 88 | static void sk_proxy_close (Socket s) |
| 89 | { |
| 90 | Proxy_Socket ps = (Proxy_Socket) s; |
| 91 | |
| 92 | while (ps->lock_close) ; |
| 93 | sk_close(ps->sub_socket); |
| 94 | sfree(ps); |
| 95 | } |
| 96 | |
| 97 | static int sk_proxy_write (Socket s, char *data, int len) |
| 98 | { |
| 99 | Proxy_Socket ps = (Proxy_Socket) s; |
| 100 | |
| 101 | while (ps->lock_write) ; |
| 102 | if (ps->state != PROXY_STATE_ACTIVE) { |
| 103 | bufchain_add(&ps->pending_output_data, data, len); |
| 104 | return bufchain_size(&ps->pending_output_data); |
| 105 | } |
| 106 | return sk_write(ps->sub_socket, data, len); |
| 107 | } |
| 108 | |
| 109 | static int sk_proxy_write_oob (Socket s, char *data, int len) |
| 110 | { |
| 111 | Proxy_Socket ps = (Proxy_Socket) s; |
| 112 | |
| 113 | while (ps->lock_write_oob) ; |
| 114 | if (ps->state != PROXY_STATE_ACTIVE) { |
| 115 | bufchain_clear(&ps->pending_output_data); |
| 116 | bufchain_clear(&ps->pending_oob_output_data); |
| 117 | bufchain_add(&ps->pending_oob_output_data, data, len); |
| 118 | return len; |
| 119 | } |
| 120 | return sk_write_oob(ps->sub_socket, data, len); |
| 121 | } |
| 122 | |
| 123 | static void sk_proxy_flush (Socket s) |
| 124 | { |
| 125 | Proxy_Socket ps = (Proxy_Socket) s; |
| 126 | |
| 127 | while (ps->lock_flush) ; |
| 128 | if (ps->state != PROXY_STATE_ACTIVE) { |
| 129 | ps->pending_flush = 1; |
| 130 | return; |
| 131 | } |
| 132 | sk_flush(ps->sub_socket); |
| 133 | } |
| 134 | |
| 135 | static void sk_proxy_set_private_ptr (Socket s, void *ptr) |
| 136 | { |
| 137 | Proxy_Socket ps = (Proxy_Socket) s; |
| 138 | sk_set_private_ptr(ps->sub_socket, ptr); |
| 139 | } |
| 140 | |
| 141 | static void * sk_proxy_get_private_ptr (Socket s) |
| 142 | { |
| 143 | Proxy_Socket ps = (Proxy_Socket) s; |
| 144 | return sk_get_private_ptr(ps->sub_socket); |
| 145 | } |
| 146 | |
| 147 | static void sk_proxy_set_frozen (Socket s, int is_frozen) |
| 148 | { |
| 149 | Proxy_Socket ps = (Proxy_Socket) s; |
| 150 | |
| 151 | while (ps->lock_freeze) ; |
| 152 | if (ps->state != PROXY_STATE_ACTIVE) { |
| 153 | ps->freeze = is_frozen; |
| 154 | return; |
| 155 | } |
| 156 | sk_set_frozen(ps->sub_socket, is_frozen); |
| 157 | } |
| 158 | |
| 159 | static char * sk_proxy_socket_error (Socket s) |
| 160 | { |
| 161 | Proxy_Socket ps = (Proxy_Socket) s; |
| 162 | if (ps->error != NULL || ps->sub_socket == NULL) { |
| 163 | return ps->error; |
| 164 | } |
| 165 | return sk_socket_error(ps->sub_socket); |
| 166 | } |
| 167 | |
| 168 | /* basic proxy plug functions */ |
| 169 | |
| 170 | static int plug_proxy_closing (Plug p, char *error_msg, |
| 171 | int error_code, int calling_back) |
| 172 | { |
| 173 | Proxy_Plug pp = (Proxy_Plug) p; |
| 174 | Proxy_Socket ps = pp->proxy_socket; |
| 175 | |
| 176 | while (ps->lock_closing) ; |
| 177 | if (ps->state != PROXY_STATE_ACTIVE) { |
| 178 | ps->closing_error_msg = error_msg; |
| 179 | ps->closing_error_code = error_code; |
| 180 | ps->closing_calling_back = calling_back; |
| 181 | return ps->negotiate(ps, PROXY_CHANGE_CLOSING); |
| 182 | } |
| 183 | return plug_closing(ps->plug, error_msg, |
| 184 | error_code, calling_back); |
| 185 | } |
| 186 | |
| 187 | static int plug_proxy_receive (Plug p, int urgent, char *data, int len) |
| 188 | { |
| 189 | Proxy_Plug pp = (Proxy_Plug) p; |
| 190 | Proxy_Socket ps = pp->proxy_socket; |
| 191 | |
| 192 | while (ps->lock_receive) ; |
| 193 | if (ps->state != PROXY_STATE_ACTIVE) { |
| 194 | /* we will lose the urgentness of this data, but since most, |
| 195 | * if not all, of this data will be consumed by the negotiation |
| 196 | * process, hopefully it won't affect the protocol above us |
| 197 | */ |
| 198 | bufchain_add(&ps->pending_input_data, data, len); |
| 199 | ps->receive_urgent = urgent; |
| 200 | ps->receive_data = data; |
| 201 | ps->receive_len = len; |
| 202 | return ps->negotiate(ps, PROXY_CHANGE_RECEIVE); |
| 203 | } |
| 204 | return plug_receive(ps->plug, urgent, data, len); |
| 205 | } |
| 206 | |
| 207 | static void plug_proxy_sent (Plug p, int bufsize) |
| 208 | { |
| 209 | Proxy_Plug pp = (Proxy_Plug) p; |
| 210 | Proxy_Socket ps = pp->proxy_socket; |
| 211 | |
| 212 | while (ps->lock_sent) ; |
| 213 | if (ps->state != PROXY_STATE_ACTIVE) { |
| 214 | ps->sent_bufsize = bufsize; |
| 215 | ps->negotiate(ps, PROXY_CHANGE_SENT); |
| 216 | return; |
| 217 | } |
| 218 | plug_sent(ps->plug, bufsize); |
| 219 | } |
| 220 | |
| 221 | static int plug_proxy_accepting (Plug p, void *sock) |
| 222 | { |
| 223 | Proxy_Plug pp = (Proxy_Plug) p; |
| 224 | Proxy_Socket ps = pp->proxy_socket; |
| 225 | |
| 226 | while (ps->lock_accepting) ; |
| 227 | if (ps->state != PROXY_STATE_ACTIVE) { |
| 228 | ps->accepting_sock = sock; |
| 229 | return ps->negotiate(ps, PROXY_CHANGE_ACCEPTING); |
| 230 | } |
| 231 | return plug_accepting(ps->plug, sock); |
| 232 | } |
| 233 | |
| 234 | static int proxy_for_destination (SockAddr addr, char * hostname, int port) |
| 235 | { |
| 236 | int s = 0, e = 0; |
| 237 | char hostip[64]; |
| 238 | int hostip_len, hostname_len; |
| 239 | char * exclude_list; |
| 240 | |
| 241 | /* we want a string representation of the IP address for comparisons */ |
| 242 | sk_getaddr(addr, hostip, 64); |
| 243 | |
| 244 | hostip_len = strlen(hostip); |
| 245 | hostname_len = strlen(hostname); |
| 246 | |
| 247 | exclude_list = cfg.proxy_exclude_list; |
| 248 | |
| 249 | /* now parse the exclude list, and see if either our IP |
| 250 | * or hostname matches anything in it. |
| 251 | */ |
| 252 | |
| 253 | while (exclude_list[s]) { |
| 254 | while (exclude_list[s] && |
| 255 | (isspace(exclude_list[s]) || |
| 256 | exclude_list[s] == ',')) s++; |
| 257 | |
| 258 | if (!exclude_list[s]) break; |
| 259 | |
| 260 | e = s; |
| 261 | |
| 262 | while (exclude_list[e] && |
| 263 | (isalnum(exclude_list[e]) || |
| 264 | exclude_list[e] == '-' || |
| 265 | exclude_list[e] == '.' || |
| 266 | exclude_list[e] == '*')) e++; |
| 267 | |
| 268 | if (exclude_list[s] == '*') { |
| 269 | /* wildcard at beginning of entry */ |
| 270 | |
| 271 | if (strnicmp(hostip + hostip_len - (e - s - 1), |
| 272 | exclude_list + s + 1, e - s - 1) == 0 || |
| 273 | strnicmp(hostname + hostname_len - (e - s - 1), |
| 274 | exclude_list + s + 1, e - s - 1) == 0) |
| 275 | return 0; /* IP/hostname range excluded. do not use proxy. */ |
| 276 | |
| 277 | } else if (exclude_list[e-1] == '*') { |
| 278 | /* wildcard at end of entry */ |
| 279 | |
| 280 | if (strnicmp(hostip, exclude_list + s, e - s - 1) == 0 || |
| 281 | strnicmp(hostname, exclude_list + s, e - s - 1) == 0) |
| 282 | return 0; /* IP/hostname range excluded. do not use proxy. */ |
| 283 | |
| 284 | } else { |
| 285 | /* no wildcard at either end, so let's try an absolute |
| 286 | * match (ie. a specific IP) |
| 287 | */ |
| 288 | |
| 289 | if (stricmp(hostip, exclude_list + s) == 0) |
| 290 | return 0; /* IP/hostname excluded. do not use proxy. */ |
| 291 | if (stricmp(hostname, exclude_list + s) == 0) |
| 292 | return 0; /* IP/hostname excluded. do not use proxy. */ |
| 293 | } |
| 294 | |
| 295 | s = e; |
| 296 | } |
| 297 | |
| 298 | /* no matches in the exclude list, so use the proxy */ |
| 299 | return 1; |
| 300 | } |
| 301 | |
| 302 | Socket new_connection(SockAddr addr, char *hostname, |
| 303 | int port, int privport, |
| 304 | int oobinline, int nodelay, Plug plug) |
| 305 | { |
| 306 | static struct socket_function_table socket_fn_table = { |
| 307 | sk_proxy_plug, |
| 308 | sk_proxy_close, |
| 309 | sk_proxy_write, |
| 310 | sk_proxy_write_oob, |
| 311 | sk_proxy_flush, |
| 312 | sk_proxy_set_private_ptr, |
| 313 | sk_proxy_get_private_ptr, |
| 314 | sk_proxy_set_frozen, |
| 315 | sk_proxy_socket_error |
| 316 | }; |
| 317 | |
| 318 | static struct plug_function_table plug_fn_table = { |
| 319 | plug_proxy_closing, |
| 320 | plug_proxy_receive, |
| 321 | plug_proxy_sent, |
| 322 | plug_proxy_accepting |
| 323 | }; |
| 324 | |
| 325 | if (cfg.proxy_type != PROXY_NONE && |
| 326 | proxy_for_destination(addr, hostname, port)) |
| 327 | { |
| 328 | Proxy_Socket ret; |
| 329 | Proxy_Plug pplug; |
| 330 | SockAddr proxy_addr; |
| 331 | char * proxy_canonical_name; |
| 332 | |
| 333 | ret = smalloc(sizeof(struct Socket_proxy_tag)); |
| 334 | ret->fn = &socket_fn_table; |
| 335 | ret->plug = plug; |
| 336 | ret->remote_addr = addr; |
| 337 | ret->remote_port = port; |
| 338 | |
| 339 | bufchain_init(&ret->pending_input_data); |
| 340 | bufchain_init(&ret->pending_output_data); |
| 341 | bufchain_init(&ret->pending_oob_output_data); |
| 342 | |
| 343 | ret->lock_close = |
| 344 | ret->lock_write = |
| 345 | ret->lock_write_oob = |
| 346 | ret->lock_receive = |
| 347 | ret->lock_flush = |
| 348 | ret->lock_closing = |
| 349 | ret->lock_sent = |
| 350 | ret->lock_accepting = 0; |
| 351 | |
| 352 | ret->sub_socket = NULL; |
| 353 | ret->state = PROXY_STATE_NEW; |
| 354 | |
| 355 | if (cfg.proxy_type == PROXY_HTTP) { |
| 356 | ret->negotiate = proxy_http_negotiate; |
| 357 | } else if (cfg.proxy_type == PROXY_SOCKS) { |
| 358 | ret->negotiate = proxy_socks_negotiate; |
| 359 | } else if (cfg.proxy_type == PROXY_TELNET) { |
| 360 | ret->negotiate = proxy_telnet_negotiate; |
| 361 | } else { |
| 362 | ret->error = "Network error: Unknown proxy method"; |
| 363 | return (Socket) ret; |
| 364 | } |
| 365 | |
| 366 | /* create the proxy plug to map calls from the actual |
| 367 | * socket into our proxy socket layer */ |
| 368 | pplug = smalloc(sizeof(struct Plug_proxy_tag)); |
| 369 | pplug->fn = &plug_fn_table; |
| 370 | pplug->proxy_socket = ret; |
| 371 | |
| 372 | /* look-up proxy */ |
| 373 | proxy_addr = sk_namelookup(cfg.proxy_host, |
| 374 | &proxy_canonical_name); |
| 375 | sfree(proxy_canonical_name); |
| 376 | |
| 377 | /* create the actual socket we will be using, |
| 378 | * connected to our proxy server and port. |
| 379 | */ |
| 380 | ret->sub_socket = sk_new(proxy_addr, cfg.proxy_port, |
| 381 | privport, oobinline, |
| 382 | nodelay, (Plug) pplug); |
| 383 | if (sk_socket_error(ret->sub_socket) != NULL) |
| 384 | return (Socket) ret; |
| 385 | |
| 386 | sk_addr_free(proxy_addr); |
| 387 | |
| 388 | /* start the proxy negotiation process... */ |
| 389 | sk_set_frozen(ret->sub_socket, 0); |
| 390 | ret->negotiate(ret, PROXY_CHANGE_NEW); |
| 391 | |
| 392 | return (Socket) ret; |
| 393 | } |
| 394 | |
| 395 | /* no proxy, so just return the direct socket */ |
| 396 | return sk_new(addr, port, privport, oobinline, nodelay, plug); |
| 397 | } |
| 398 | |
| 399 | Socket new_listener(int port, Plug plug, int local_host_only) |
| 400 | { |
| 401 | /* TODO: SOCKS (and potentially others) support inbound |
| 402 | * TODO: connections via the proxy. support them. |
| 403 | */ |
| 404 | |
| 405 | return sk_newlistener(port, plug, local_host_only); |
| 406 | } |
| 407 | |
| 408 | /* ---------------------------------------------------------------------- |
| 409 | * HTTP CONNECT proxy type. |
| 410 | */ |
| 411 | |
| 412 | static int get_line_end (char * data, int len) |
| 413 | { |
| 414 | int off = 0; |
| 415 | |
| 416 | while (off < len) |
| 417 | { |
| 418 | if (data[off] == '\n') { |
| 419 | /* we have a newline */ |
| 420 | off++; |
| 421 | |
| 422 | /* is that the only thing on this line? */ |
| 423 | if (off <= 2) return off; |
| 424 | |
| 425 | /* if not, then there is the possibility that this header |
| 426 | * continues onto the next line, if it starts with a space |
| 427 | * or a tab. |
| 428 | */ |
| 429 | |
| 430 | if (off + 1 < len && |
| 431 | data[off+1] != ' ' && |
| 432 | data[off+1] != '\t') return off; |
| 433 | |
| 434 | /* the line does continue, so we have to keep going |
| 435 | * until we see an the header's "real" end of line. |
| 436 | */ |
| 437 | off++; |
| 438 | } |
| 439 | |
| 440 | off++; |
| 441 | } |
| 442 | |
| 443 | return -1; |
| 444 | } |
| 445 | |
| 446 | int proxy_http_negotiate (Proxy_Socket p, int change) |
| 447 | { |
| 448 | if (p->state == PROXY_STATE_NEW) { |
| 449 | /* we are just beginning the proxy negotiate process, |
| 450 | * so we'll send off the initial bits of the request. |
| 451 | * for this proxy method, it's just a simple HTTP |
| 452 | * request |
| 453 | */ |
| 454 | char buf[1024], dest[21]; |
| 455 | |
| 456 | sk_getaddr(p->remote_addr, dest, 20); |
| 457 | |
| 458 | sprintf(buf, "CONNECT %s:%i HTTP/1.1\r\nHost: %s:%i\r\n\r\n", |
| 459 | dest, p->remote_port, dest, p->remote_port); |
| 460 | sk_write(p->sub_socket, buf, strlen(buf)); |
| 461 | |
| 462 | p->state = 1; |
| 463 | |
| 464 | return 0; |
| 465 | } |
| 466 | |
| 467 | if (change == PROXY_CHANGE_CLOSING) { |
| 468 | /* if our proxy negotiation process involves closing and opening |
| 469 | * new sockets, then we would want to intercept this closing |
| 470 | * callback when we were expecting it. if we aren't anticipating |
| 471 | * a socket close, then some error must have occurred. we'll |
| 472 | * just pass those errors up to the backend. |
| 473 | */ |
| 474 | return plug_closing(p->plug, p->closing_error_msg, |
| 475 | p->closing_error_code, |
| 476 | p->closing_calling_back); |
| 477 | } |
| 478 | |
| 479 | if (change == PROXY_CHANGE_SENT) { |
| 480 | /* some (or all) of what we wrote to the proxy was sent. |
| 481 | * we don't do anything new, however, until we receive the |
| 482 | * proxy's response. we might want to set a timer so we can |
| 483 | * timeout the proxy negotiation after a while... |
| 484 | */ |
| 485 | return 0; |
| 486 | } |
| 487 | |
| 488 | if (change == PROXY_CHANGE_ACCEPTING) { |
| 489 | /* we should _never_ see this, as we are using our socket to |
| 490 | * connect to a proxy, not accepting inbound connections. |
| 491 | * what should we do? close the socket with an appropriate |
| 492 | * error message? |
| 493 | */ |
| 494 | return plug_accepting(p->plug, p->accepting_sock); |
| 495 | } |
| 496 | |
| 497 | if (change == PROXY_CHANGE_RECEIVE) { |
| 498 | /* we have received data from the underlying socket, which |
| 499 | * we'll need to parse, process, and respond to appropriately. |
| 500 | */ |
| 501 | |
| 502 | void *data; |
| 503 | int len; |
| 504 | int eol; |
| 505 | |
| 506 | if (p->state == 1) { |
| 507 | |
| 508 | int min_ver, maj_ver, status; |
| 509 | |
| 510 | /* get the status line */ |
| 511 | bufchain_prefix(&p->pending_input_data, &data, &len); |
| 512 | eol = get_line_end(data, len); |
| 513 | if (eol < 0) return 1; |
| 514 | |
| 515 | sscanf((char *)data, "HTTP/%i.%i %i", &maj_ver, &min_ver, &status); |
| 516 | |
| 517 | /* remove the status line from the input buffer. */ |
| 518 | bufchain_consume(&p->pending_input_data, eol); |
| 519 | |
| 520 | /* TODO: we need to support Proxy-Auth headers */ |
| 521 | |
| 522 | if (status < 200 || status > 299) { |
| 523 | /* error */ |
| 524 | /* TODO: return a more specific error message, |
| 525 | * TODO: based on the status code. |
| 526 | */ |
| 527 | plug_closing(p->plug, "Network error: Error while communicating with proxy", |
| 528 | PROXY_ERROR_GENERAL, 0); |
| 529 | return 1; |
| 530 | } |
| 531 | |
| 532 | p->state = 2; |
| 533 | } |
| 534 | |
| 535 | if (p->state == 2) { |
| 536 | |
| 537 | /* get headers. we're done when we get a |
| 538 | * header of length 2, (ie. just "\r\n") |
| 539 | */ |
| 540 | |
| 541 | bufchain_prefix(&p->pending_input_data, &data, &len); |
| 542 | eol = get_line_end(data, len); |
| 543 | while (eol > 2) |
| 544 | { |
| 545 | /* TODO: Proxy-Auth stuff. in some cases, we will |
| 546 | * TODO: need to extract information from headers. |
| 547 | */ |
| 548 | bufchain_consume(&p->pending_input_data, eol); |
| 549 | bufchain_prefix(&p->pending_input_data, &data, &len); |
| 550 | eol = get_line_end(data, len); |
| 551 | } |
| 552 | |
| 553 | if (eol == 2) { |
| 554 | /* we're done */ |
| 555 | bufchain_consume(&p->pending_input_data, 2); |
| 556 | proxy_activate(p); |
| 557 | /* proxy activate will have dealt with |
| 558 | * whatever is left of the buffer */ |
| 559 | return 1; |
| 560 | } |
| 561 | |
| 562 | return 1; |
| 563 | } |
| 564 | } |
| 565 | |
| 566 | plug_closing(p->plug, "Network error: Unexpected proxy error", |
| 567 | PROXY_ERROR_UNEXPECTED, 0); |
| 568 | return 0; |
| 569 | } |
| 570 | |
| 571 | /* ---------------------------------------------------------------------- |
| 572 | * SOCKS proxy type (as yet unimplemented). |
| 573 | */ |
| 574 | |
| 575 | int proxy_socks_negotiate (Proxy_Socket p, int change) |
| 576 | { |
| 577 | p->error = "Network error: SOCKS proxy implementation is incomplete"; |
| 578 | return 0; |
| 579 | } |
| 580 | |
| 581 | /* ---------------------------------------------------------------------- |
| 582 | * `Telnet' proxy type (as yet unimplemented). |
| 583 | * |
| 584 | * (This is for ad-hoc proxies where you connect to the proxy's |
| 585 | * telnet port and send a command such as `connect host port'. The |
| 586 | * command is configurable, since this proxy type is typically not |
| 587 | * standardised or at all well-defined.) |
| 588 | */ |
| 589 | |
| 590 | int proxy_telnet_negotiate (Proxy_Socket p, int change) |
| 591 | { |
| 592 | p->error = "Network error: Telnet proxy implementation is incomplete"; |
| 593 | return 0; |
| 594 | } |