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