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         (void)type;
  39         connection_t *c = handle;
  40
  41         if(!c) {
  42                 logger(DEBUG_ALWAYS, LOG_ERR, "send_meta_sptps() called with NULL pointer!");
  43                 abort();
  44         }
  45
  46         buffer_add(&c->outbuf, buffer, length);
  47         io_set(&c->io, IO_READ | IO_WRITE);
  48
  49         return true;
  50 }
  51
  52 bool send_meta(connection_t *c, const char *buffer, size_t length) {
  53         if(!c) {
  54                 logger(DEBUG_ALWAYS, LOG_ERR, "send_meta() called with NULL pointer!");
  55                 abort();
  56         }
  57
  58         logger(DEBUG_META, LOG_DEBUG, "Sending %lu bytes of metadata to %s (%s)", (unsigned long)length,
  59                c->name, c->hostname);
  60
  61         if(c->protocol_minor >= 2) {
  62                 return sptps_send_record(&c->sptps, 0, buffer, length);
  63         }
  64
  65         /* Add our data to buffer */
  66         if(c->status.encryptout) {
  67 #ifdef DISABLE_LEGACY
  68                 return false;
  69 #else
  70
  71                 if(length > c->outbudget) {
  72                         logger(DEBUG_META, LOG_ERR, "Byte limit exceeded for encryption to %s (%s)", c->name, c->hostname);
  73                         return false;
  74                 } else {
  75                         c->outbudget -= length;
  76                 }
  77
  78                 size_t outlen = length;
  79
  80                 if(!cipher_encrypt(c->outcipher, buffer, length, buffer_prepare(&c->outbuf, length), &outlen, false) || outlen != length) {
  81                         logger(DEBUG_ALWAYS, LOG_ERR, "Error while encrypting metadata to %s (%s)",
  82                                c->name, c->hostname);
  83                         return false;
  84                 }
  85
  86 #endif
  87         } else {
  88                 buffer_add(&c->outbuf, buffer, length);
  89         }
  90
  91         io_set(&c->io, IO_READ | IO_WRITE);
  92
  93         return true;
  94 }
  95
  96 void send_meta_raw(connection_t *c, const char *buffer, size_t length) {
  97         if(!c) {
  98                 logger(DEBUG_ALWAYS, LOG_ERR, "send_meta() called with NULL pointer!");
  99                 abort();
 100         }
 101
 102         logger(DEBUG_META, LOG_DEBUG, "Sending %lu bytes of raw metadata to %s (%s)", (unsigned long)length,
 103                c->name, c->hostname);
 104
 105         buffer_add(&c->outbuf, buffer, length);
 106
 107         io_set(&c->io, IO_READ | IO_WRITE);
 108 }
 109
 110 void broadcast_meta(connection_t *from, const char *buffer, size_t length) {
 111         for list_each(connection_t, c, connection_list)
 112                 if(c != from && c->edge) {
 113                         send_meta(c, buffer, length);
 114                 }
 115 }
 116
 117 bool receive_meta_sptps(void *handle, uint8_t type, const void *vdata, uint16_t length) {
 118         const char *data = vdata;
 119         connection_t *c = handle;
 120
 121         if(!c) {
 122                 logger(DEBUG_ALWAYS, LOG_ERR, "receive_meta_sptps() called with NULL pointer!");
 123                 abort();
 124         }
 125
 126         if(type == SPTPS_HANDSHAKE) {
 127                 if(c->allow_request == ACK) {
 128                         return send_ack(c);
 129                 } else {
 130                         return true;
 131                 }
 132         }
 133
 134         if(!data) {
 135                 return true;
 136         }
 137
 138         /* Are we receiving a TCPpacket? */
 139
 140         if(c->tcplen) {
 141                 if(length != c->tcplen) {
 142                         return false;
 143                 }
 144
 145                 receive_tcppacket(c, data, length);
 146                 c->tcplen = 0;
 147                 return true;
 148         }
 149
 150         /* Change newline to null byte, just like non-SPTPS requests */
 151
 152         if(data[length - 1] == '\n') {
 153                 ((char *)data)[length - 1] = 0;
 154         }
 155
 156         /* Otherwise we are waiting for a request */
 157
 158         return receive_request(c, data);
 159 }
 160
 161 bool receive_meta(connection_t *c) {
 162         ssize_t inlen;
 163         char inbuf[MAXBUFSIZE];
 164         char *bufp = inbuf, *endp;
 165
 166         /* Strategy:
 167            - Read as much as possible from the TCP socket in one go.
 168            - Decrypt it.
 169            - Check if a full request is in the input buffer.
 170            - If yes, process request and remove it from the buffer,
 171            then check again.
 172            - If not, keep stuff in buffer and exit.
 173          */
 174
 175         buffer_compact(&c->inbuf, MAXBUFSIZE);
 176
 177         if(sizeof(inbuf) <= c->inbuf.len) {
 178                 logger(DEBUG_ALWAYS, LOG_ERR, "Input buffer full for %s (%s)", c->name, c->hostname);
 179                 return false;
 180         }
 181
 182         inlen = recv(c->socket, inbuf, sizeof(inbuf) - c->inbuf.len, 0);
 183
 184         if(inlen <= 0) {
 185                 if(!inlen || !sockerrno) {
 186                         logger(DEBUG_CONNECTIONS, LOG_NOTICE, "Connection closed by %s (%s)",
 187                                c->name, c->hostname);
 188                 } else if(sockwouldblock(sockerrno)) {
 189                         return true;
 190                 } else
 191                         logger(DEBUG_ALWAYS, LOG_ERR, "Metadata socket read error for %s (%s): %s",
 192                                c->name, c->hostname, sockstrerror(sockerrno));
 193
 194                 return false;
 195         }
 196
 197         do {
 198                 /* Are we receiving a SPTPS packet? */
 199
 200                 if(c->sptpslen) {
 201                         ssize_t len = MIN(inlen, c->sptpslen - c->inbuf.len);
 202                         buffer_add(&c->inbuf, bufp, len);
 203
 204                         char *sptpspacket = buffer_read(&c->inbuf, c->sptpslen);
 205
 206                         if(!sptpspacket) {
 207                                 return true;
 208                         }
 209
 210                         if(!receive_tcppacket_sptps(c, sptpspacket, c->sptpslen)) {
 211                                 return false;
 212                         }
 213
 214                         c->sptpslen = 0;
 215
 216                         bufp += len;
 217                         inlen -= len;
 218                         continue;
 219                 }
 220
 221                 if(c->protocol_minor >= 2) {
 222                         size_t len = sptps_receive_data(&c->sptps, bufp, inlen);
 223
 224                         if(!len) {
 225                                 return false;
 226                         }
 227
 228                         bufp += len;
 229                         inlen -= len;
 230                         continue;
 231                 }
 232
 233                 if(!c->status.decryptin) {
 234                         endp = memchr(bufp, '\n', inlen);
 235
 236                         if(endp) {
 237                                 endp++;
 238                         } else {
 239                                 endp = bufp + inlen;
 240                         }
 241
 242                         buffer_add(&c->inbuf, bufp, endp - bufp);
 243
 244                         inlen -= endp - bufp;
 245                         bufp = endp;
 246                 } else {
 247 #ifdef DISABLE_LEGACY
 248                         return false;
 249 #else
 250
 251                         if((size_t)inlen > c->inbudget) {
 252                                 logger(DEBUG_META, LOG_ERR, "Byte limit exceeded for decryption from %s (%s)", c->name, c->hostname);
 253                                 return false;
 254                         } else {
 255                                 c->inbudget -= inlen;
 256                         }
 257
 258                         size_t outlen = inlen;
 259
 260                         if(!cipher_decrypt(c->incipher, bufp, inlen, buffer_prepare(&c->inbuf, inlen), &outlen, false) || (size_t)inlen != outlen) {
 261                                 logger(DEBUG_ALWAYS, LOG_ERR, "Error while decrypting metadata from %s (%s)",
 262                                        c->name, c->hostname);
 263                                 return false;
 264                         }
 265
 266                         inlen = 0;
 267 #endif
 268                 }
 269
 270                 while(c->inbuf.len) {
 271                         /* Are we receiving a TCPpacket? */
 272
 273                         if(c->tcplen) {
 274                                 char *tcpbuffer = buffer_read(&c->inbuf, c->tcplen);
 275
 276                                 if(!tcpbuffer) {
 277                                         break;
 278                                 }
 279
 280                                 if(!c->node) {
 281                                         if(c->outgoing && proxytype == PROXY_SOCKS4 && c->allow_request == ID) {
 282                                                 if(tcpbuffer[0] == 0 && tcpbuffer[1] == 0x5a) {
 283                                                         logger(DEBUG_CONNECTIONS, LOG_DEBUG, "Proxy request granted");
 284                                                 } else {
 285                                                         logger(DEBUG_CONNECTIONS, LOG_ERR, "Proxy request rejected");
 286                                                         return false;
 287                                                 }
 288                                         } else if(c->outgoing && proxytype == PROXY_SOCKS5 && c->allow_request == ID) {
 289                                                 if(tcpbuffer[0] != 5) {
 290                                                         logger(DEBUG_CONNECTIONS, LOG_ERR, "Invalid response from proxy server");
 291                                                         return false;
 292                                                 }
 293
 294                                                 if(tcpbuffer[1] == (char)0xff) {
 295                                                         logger(DEBUG_CONNECTIONS, LOG_ERR, "Proxy request rejected: unsuitable authentication method");
 296                                                         return false;
 297                                                 }
 298
 299                                                 if(tcpbuffer[2] != 5) {
 300                                                         logger(DEBUG_CONNECTIONS, LOG_ERR, "Invalid response from proxy server");
 301                                                         return false;
 302                                                 }
 303
 304                                                 if(tcpbuffer[3] == 0) {
 305                                                         logger(DEBUG_CONNECTIONS, LOG_DEBUG, "Proxy request granted");
 306                                                 } else {
 307                                                         logger(DEBUG_CONNECTIONS, LOG_DEBUG, "Proxy request rejected");
 308                                                         return false;
 309                                                 }
 310                                         } else {
 311                                                 logger(DEBUG_CONNECTIONS, LOG_ERR, "c->tcplen set but c->node is NULL!");
 312                                                 abort();
 313                                         }
 314                                 } else {
 315                                         if(c->allow_request == ALL) {
 316                                                 receive_tcppacket(c, tcpbuffer, c->tcplen);
 317                                         } else {
 318                                                 logger(DEBUG_CONNECTIONS, LOG_ERR, "Got unauthorized TCP packet from %s (%s)", c->name, c->hostname);
 319                                                 return false;
 320                                         }
 321                                 }
 322
 323                                 c->tcplen = 0;
 324                         }
 325
 326                         /* Otherwise we are waiting for a request */
 327
 328                         char *request = buffer_readline(&c->inbuf);
 329
 330                         if(request) {
 331                                 bool result = receive_request(c, request);
 332
 333                                 if(!result) {
 334                                         return false;
 335                                 }
 336
 337                                 continue;
 338                         } else {
 339                                 break;
 340                         }
 341                 }
 342         } while(inlen);
 343
 344         return true;
 345 }