www.tinc-vpn.org Git - tinc/blob - src/meta.c

   1 /*
   2     meta.c -- handle the meta communication
   3     Copyright (C) 2000-2014 Guus Sliepen <guus@tinc-vpn.org>,
   4                   2000-2005 Ivo Timmermans
   5                   2006      Scott Lamb <slamb@slamb.org>
   6
   7     This program is free software; you can redistribute it and/or modify
   8     it under the terms of the GNU General Public License as published by
   9     the Free Software Foundation; either version 2 of the License, or
  10     (at your option) any later version.
  11
  12     This program is distributed in the hope that it will be useful,
  13     but WITHOUT ANY WARRANTY; without even the implied warranty of
  14     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15     GNU General Public License for more details.
  16
  17     You should have received a copy of the GNU General Public License along
  18     with this program; if not, write to the Free Software Foundation, Inc.,
  19     51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  20 */
  21
  22 #include "system.h"
  23
  24 #include "cipher.h"
  25 #include "connection.h"
  26 #include "logger.h"
  27 #include "meta.h"
  28 #include "net.h"
  29 #include "protocol.h"
  30 #include "utils.h"
  31 #include "xalloc.h"
  32
  33 #ifndef MIN
  34 #define MIN(x, y) (((x)<(y))?(x):(y))
  35 #endif
  36
  37 bool send_meta_sptps(void *handle, uint8_t type, const void *buffer, size_t length) {
  38         connection_t *c = handle;
  39
  40         if(!c) {
  41                 logger(DEBUG_ALWAYS, LOG_ERR, "send_meta_sptps() called with NULL pointer!");
  42                 abort();
  43         }
  44
  45         buffer_add(&c->outbuf, buffer, length);
  46         io_set(&c->io, IO_READ | IO_WRITE);
  47
  48         return true;
  49 }
  50
  51 bool send_meta(connection_t *c, const char *buffer, int length) {
  52         if(!c) {
  53                 logger(DEBUG_ALWAYS, LOG_ERR, "send_meta() called with NULL pointer!");
  54                 abort();
  55         }
  56
  57         logger(DEBUG_META, LOG_DEBUG, "Sending %d bytes of metadata to %s (%s)", length,
  58                c->name, c->hostname);
  59
  60         if(c->protocol_minor >= 2) {
  61                 return sptps_send_record(&c->sptps, 0, buffer, length);
  62         }
  63
  64         /* Add our data to buffer */
  65         if(c->status.encryptout) {
  66 #ifdef DISABLE_LEGACY
  67                 return false;
  68 #else
  69
  70                 if(length > c->outbudget) {
  71                         logger(DEBUG_META, LOG_ERR, "Byte limit exceeded for encryption to %s (%s)", c->name, c->hostname);
  72                         return false;
  73                 } else {
  74                         c->outbudget -= length;
  75                 }
  76
  77                 size_t outlen = length;
  78
  79                 if(!cipher_encrypt(c->outcipher, buffer, length, buffer_prepare(&c->outbuf, length), &outlen, false) || outlen != length) {
  80                         logger(DEBUG_ALWAYS, LOG_ERR, "Error while encrypting metadata to %s (%s)",
  81                                c->name, c->hostname);
  82                         return false;
  83                 }
  84
  85 #endif
  86         } else {
  87                 buffer_add(&c->outbuf, buffer, length);
  88         }
  89
  90         io_set(&c->io, IO_READ | IO_WRITE);
  91
  92         return true;
  93 }
  94
  95 void send_meta_raw(connection_t *c, const char *buffer, int length) {
  96         if(!c) {
  97                 logger(DEBUG_ALWAYS, LOG_ERR, "send_meta() called with NULL pointer!");
  98                 abort();
  99         }
 100
 101         logger(DEBUG_META, LOG_DEBUG, "Sending %d bytes of raw metadata to %s (%s)", length,
 102                c->name, c->hostname);
 103
 104         buffer_add(&c->outbuf, buffer, length);
 105
 106         io_set(&c->io, IO_READ | IO_WRITE);
 107 }
 108
 109 void broadcast_meta(connection_t *from, const char *buffer, int length) {
 110         for list_each(connection_t, c, connection_list)
 111                 if(c != from && c->edge) {
 112                         send_meta(c, buffer, length);
 113                 }
 114 }
 115
 116 bool receive_meta_sptps(void *handle, uint8_t type, const void *vdata, uint16_t length) {
 117         const char *data = vdata;
 118         connection_t *c = handle;
 119
 120         if(!c) {
 121                 logger(DEBUG_ALWAYS, LOG_ERR, "receive_meta_sptps() called with NULL pointer!");
 122                 abort();
 123         }
 124
 125         if(type == SPTPS_HANDSHAKE) {
 126                 if(c->allow_request == ACK) {
 127                         return send_ack(c);
 128                 } else {
 129                         return true;
 130                 }
 131         }
 132
 133         if(!data) {
 134                 return true;
 135         }
 136
 137         /* Are we receiving a TCPpacket? */
 138
 139         if(c->tcplen) {
 140                 if(length != c->tcplen) {
 141                         return false;
 142                 }
 143
 144                 receive_tcppacket(c, data, length);
 145                 c->tcplen = 0;
 146                 return true;
 147         }
 148
 149         /* Change newline to null byte, just like non-SPTPS requests */
 150
 151         if(data[length - 1] == '\n') {
 152                 ((char *)data)[length - 1] = 0;
 153         }
 154
 155         /* Otherwise we are waiting for a request */
 156
 157         return receive_request(c, data);
 158 }
 159
 160 bool receive_meta(connection_t *c) {
 161         int inlen;
 162         char inbuf[MAXBUFSIZE];
 163         char *bufp = inbuf, *endp;
 164
 165         /* Strategy:
 166            - Read as much as possible from the TCP socket in one go.
 167            - Decrypt it.
 168            - Check if a full request is in the input buffer.
 169            - If yes, process request and remove it from the buffer,
 170            then check again.
 171            - If not, keep stuff in buffer and exit.
 172          */
 173
 174         buffer_compact(&c->inbuf, MAXBUFSIZE);
 175
 176         if(sizeof(inbuf) <= c->inbuf.len) {
 177                 logger(DEBUG_ALWAYS, LOG_ERR, "Input buffer full for %s (%s)", c->name, c->hostname);
 178                 return false;
 179         }
 180
 181         inlen = recv(c->socket, inbuf, sizeof(inbuf) - c->inbuf.len, 0);
 182
 183         if(inlen <= 0) {
 184                 if(!inlen || !sockerrno) {
 185                         logger(DEBUG_CONNECTIONS, LOG_NOTICE, "Connection closed by %s (%s)",
 186                                c->name, c->hostname);
 187                 } else if(sockwouldblock(sockerrno)) {
 188                         return true;
 189                 } else
 190                         logger(DEBUG_ALWAYS, LOG_ERR, "Metadata socket read error for %s (%s): %s",
 191                                c->name, c->hostname, sockstrerror(sockerrno));
 192
 193                 return false;
 194         }
 195
 196         do {
 197                 /* Are we receiving a SPTPS packet? */
 198
 199                 if(c->sptpslen) {
 200                         int len = MIN(inlen, c->sptpslen - c->inbuf.len);
 201                         buffer_add(&c->inbuf, bufp, len);
 202
 203                         char *sptpspacket = buffer_read(&c->inbuf, c->sptpslen);
 204
 205                         if(!sptpspacket) {
 206                                 return true;
 207                         }
 208
 209                         if(!receive_tcppacket_sptps(c, sptpspacket, c->sptpslen)) {
 210                                 return false;
 211                         }
 212
 213                         c->sptpslen = 0;
 214
 215                         bufp += len;
 216                         inlen -= len;
 217                         continue;
 218                 }
 219
 220                 if(c->protocol_minor >= 2) {
 221                         int len = sptps_receive_data(&c->sptps, bufp, inlen);
 222
 223                         if(!len) {
 224                                 return false;
 225                         }
 226
 227                         bufp += len;
 228                         inlen -= len;
 229                         continue;
 230                 }
 231
 232                 if(!c->status.decryptin) {
 233                         endp = memchr(bufp, '\n', inlen);
 234
 235                         if(endp) {
 236                                 endp++;
 237                         } else {
 238                                 endp = bufp + inlen;
 239                         }
 240
 241                         buffer_add(&c->inbuf, bufp, endp - bufp);
 242
 243                         inlen -= endp - bufp;
 244                         bufp = endp;
 245                 } else {
 246 #ifdef DISABLE_LEGACY
 247                         return false;
 248 #else
 249
 250                         if(inlen > c->inbudget) {
 251                                 logger(DEBUG_META, LOG_ERR, "yte limit exceeded for decryption from %s (%s)", c->name, c->hostname);
 252                                 return false;
 253                         } else {
 254                                 c->inbudget -= inlen;
 255                         }
 256
 257                         size_t outlen = inlen;
 258
 259                         if(!cipher_decrypt(c->incipher, bufp, inlen, buffer_prepare(&c->inbuf, inlen), &outlen, false) || inlen != outlen) {
 260                                 logger(DEBUG_ALWAYS, LOG_ERR, "Error while decrypting metadata from %s (%s)",
 261                                        c->name, c->hostname);
 262                                 return false;
 263                         }
 264
 265                         inlen = 0;
 266 #endif
 267                 }
 268
 269                 while(c->inbuf.len) {
 270                         /* Are we receiving a TCPpacket? */
 271
 272                         if(c->tcplen) {
 273                                 char *tcpbuffer = buffer_read(&c->inbuf, c->tcplen);
 274
 275                                 if(!tcpbuffer) {
 276                                         break;
 277                                 }
 278
 279                                 if(!c->node) {
 280                                         if(c->outgoing && proxytype == PROXY_SOCKS4 && c->allow_request == ID) {
 281                                                 if(tcpbuffer[0] == 0 && tcpbuffer[1] == 0x5a) {
 282                                                         logger(DEBUG_CONNECTIONS, LOG_DEBUG, "Proxy request granted");
 283                                                 } else {
 284                                                         logger(DEBUG_CONNECTIONS, LOG_ERR, "Proxy request rejected");
 285                                                         return false;
 286                                                 }
 287                                         } else if(c->outgoing && proxytype == PROXY_SOCKS5 && c->allow_request == ID) {
 288                                                 if(tcpbuffer[0] != 5) {
 289                                                         logger(DEBUG_CONNECTIONS, LOG_ERR, "Invalid response from proxy server");
 290                                                         return false;
 291                                                 }
 292
 293                                                 if(tcpbuffer[1] == (char)0xff) {
 294                                                         logger(DEBUG_CONNECTIONS, LOG_ERR, "Proxy request rejected: unsuitable authentication method");
 295                                                         return false;
 296                                                 }
 297
 298                                                 if(tcpbuffer[2] != 5) {
 299                                                         logger(DEBUG_CONNECTIONS, LOG_ERR, "Invalid response from proxy server");
 300                                                         return false;
 301                                                 }
 302
 303                                                 if(tcpbuffer[3] == 0) {
 304                                                         logger(DEBUG_CONNECTIONS, LOG_DEBUG, "Proxy request granted");
 305                                                 } else {
 306                                                         logger(DEBUG_CONNECTIONS, LOG_DEBUG, "Proxy request rejected");
 307                                                         return false;
 308                                                 }
 309                                         } else {
 310                                                 logger(DEBUG_CONNECTIONS, LOG_ERR, "c->tcplen set but c->node is NULL!");
 311                                                 abort();
 312                                         }
 313                                 } else {
 314                                         if(c->allow_request == ALL) {
 315                                                 receive_tcppacket(c, tcpbuffer, c->tcplen);
 316                                         } else {
 317                                                 logger(DEBUG_CONNECTIONS, LOG_ERR, "Got unauthorized TCP packet from %s (%s)", c->name, c->hostname);
 318                                                 return false;
 319                                         }
 320                                 }
 321
 322                                 c->tcplen = 0;
 323                         }
 324
 325                         /* Otherwise we are waiting for a request */
 326
 327                         char *request = buffer_readline(&c->inbuf);
 328
 329                         if(request) {
 330                                 bool result = receive_request(c, request);
 331
 332                                 if(!result) {
 333                                         return false;
 334                                 }
 335
 336                                 continue;
 337                         } else {
 338                                 break;
 339                         }
 340                 }
 341         } while(inlen);
 342
 343         return true;
 344 }