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 bool send_meta_sptps(void *handle, uint8_t type, const void *buffer, size_t length) {
  34         connection_t *c = handle;
  35
  36         if(!c) {
  37                 logger(DEBUG_ALWAYS, LOG_ERR, "send_meta_sptps() called with NULL pointer!");
  38                 abort();
  39         }
  40
  41         buffer_add(&c->outbuf, buffer, length);
  42         io_set(&c->io, IO_READ | IO_WRITE);
  43
  44         return true;
  45 }
  46
  47 bool send_meta(connection_t *c, const char *buffer, int length) {
  48         if(!c) {
  49                 logger(DEBUG_ALWAYS, LOG_ERR, "send_meta() called with NULL pointer!");
  50                 abort();
  51         }
  52
  53         logger(DEBUG_META, LOG_DEBUG, "Sending %d bytes of metadata to %s (%s)", length,
  54                            c->name, c->hostname);
  55
  56         if(c->protocol_minor >= 2)
  57                 return sptps_send_record(&c->sptps, 0, buffer, length);
  58
  59         /* Add our data to buffer */
  60         if(c->status.encryptout) {
  61 #ifdef DISABLE_LEGACY
  62                 return false;
  63 #else
  64                 size_t outlen = length;
  65
  66                 if(!cipher_encrypt(c->outcipher, buffer, length, buffer_prepare(&c->outbuf, length), &outlen, false) || outlen != length) {
  67                         logger(DEBUG_ALWAYS, LOG_ERR, "Error while encrypting metadata to %s (%s)",
  68                                         c->name, c->hostname);
  69                         return false;
  70                 }
  71 #endif
  72         } else {
  73                 buffer_add(&c->outbuf, buffer, length);
  74         }
  75
  76         io_set(&c->io, IO_READ | IO_WRITE);
  77
  78         return true;
  79 }
  80
  81 void send_meta_raw(connection_t *c, const char *buffer, int length) {
  82         if(!c) {
  83                 logger(DEBUG_ALWAYS, LOG_ERR, "send_meta() called with NULL pointer!");
  84                 abort();
  85         }
  86
  87         logger(DEBUG_META, LOG_DEBUG, "Sending %d bytes of raw metadata to %s (%s)", length,
  88                            c->name, c->hostname);
  89
  90         buffer_add(&c->outbuf, buffer, length);
  91
  92         io_set(&c->io, IO_READ | IO_WRITE);
  93 }
  94
  95 void broadcast_meta(connection_t *from, const char *buffer, int length) {
  96         for list_each(connection_t, c, connection_list)
  97                 if(c != from && c->edge)
  98                         send_meta(c, buffer, length);
  99 }
 100
 101 bool receive_meta_sptps(void *handle, uint8_t type, const void *vdata, uint16_t length) {
 102         const char *data = vdata;
 103         connection_t *c = handle;
 104
 105         if(!c) {
 106                 logger(DEBUG_ALWAYS, LOG_ERR, "receive_meta_sptps() called with NULL pointer!");
 107                 abort();
 108         }
 109
 110         if(type == SPTPS_HANDSHAKE) {
 111                 if(c->allow_request == ACK)
 112                         return send_ack(c);
 113                 else
 114                         return true;
 115         }
 116
 117         if(!data)
 118                 return true;
 119
 120         /* Are we receiving a TCPpacket? */
 121
 122         if(c->tcplen) {
 123                 if(length != c->tcplen)
 124                         return false;
 125                 receive_tcppacket(c, data, length);
 126                 c->tcplen = 0;
 127                 return true;
 128         }
 129
 130         /* Change newline to null byte, just like non-SPTPS requests */
 131
 132         if(data[length - 1] == '\n')
 133                 ((char *)data)[length - 1] = 0;
 134
 135         /* Otherwise we are waiting for a request */
 136
 137         return receive_request(c, data);
 138 }
 139
 140 bool receive_meta(connection_t *c) {
 141         int inlen;
 142         char inbuf[MAXBUFSIZE];
 143         char *bufp = inbuf, *endp;
 144
 145         /* Strategy:
 146            - Read as much as possible from the TCP socket in one go.
 147            - Decrypt it.
 148            - Check if a full request is in the input buffer.
 149            - If yes, process request and remove it from the buffer,
 150            then check again.
 151            - If not, keep stuff in buffer and exit.
 152          */
 153
 154         buffer_compact(&c->inbuf, MAXBUFSIZE);
 155
 156         if(sizeof inbuf <= c->inbuf.len) {
 157                 logger(DEBUG_ALWAYS, LOG_ERR, "Input buffer full for %s (%s)", c->name, c->hostname);
 158                 return false;
 159         }
 160
 161         inlen = recv(c->socket, inbuf, sizeof inbuf - c->inbuf.len, 0);
 162
 163         if(inlen <= 0) {
 164                 if(!inlen || !sockerrno) {
 165                         logger(DEBUG_CONNECTIONS, LOG_NOTICE, "Connection closed by %s (%s)",
 166                                            c->name, c->hostname);
 167                 } else if(sockwouldblock(sockerrno))
 168                         return true;
 169                 else
 170                         logger(DEBUG_ALWAYS, LOG_ERR, "Metadata socket read error for %s (%s): %s",
 171                                    c->name, c->hostname, sockstrerror(sockerrno));
 172                 return false;
 173         }
 174
 175         do {
 176                 /* Are we receiving a SPTPS packet? */
 177
 178                 if(c->sptpslen) {
 179                         int len = MIN(inlen, c->sptpslen - c->inbuf.len);
 180                         buffer_add(&c->inbuf, bufp, len);
 181
 182                         char *sptpspacket = buffer_read(&c->inbuf, c->sptpslen);
 183                         if(!sptpspacket)
 184                                 return true;
 185
 186                         if(!receive_tcppacket_sptps(c, sptpspacket, c->sptpslen))
 187                                 return false;
 188                         c->sptpslen = 0;
 189
 190                         bufp += len;
 191                         inlen -= len;
 192                         continue;
 193                 }
 194
 195                 if(c->protocol_minor >= 2) {
 196                         int len = sptps_receive_data(&c->sptps, bufp, inlen);
 197                         if(!len)
 198                                 return false;
 199                         bufp += len;
 200                         inlen -= len;
 201                         continue;
 202                 }
 203
 204                 if(!c->status.decryptin) {
 205                         endp = memchr(bufp, '\n', inlen);
 206                         if(endp)
 207                                 endp++;
 208                         else
 209                                 endp = bufp + inlen;
 210
 211                         buffer_add(&c->inbuf, bufp, endp - bufp);
 212
 213                         inlen -= endp - bufp;
 214                         bufp = endp;
 215                 } else {
 216 #ifdef DISABLE_LEGACY
 217                         return false;
 218 #else
 219                         size_t outlen = inlen;
 220
 221                         if(!cipher_decrypt(c->incipher, bufp, inlen, buffer_prepare(&c->inbuf, inlen), &outlen, false) || inlen != outlen) {
 222                                 logger(DEBUG_ALWAYS, LOG_ERR, "Error while decrypting metadata from %s (%s)",
 223                                            c->name, c->hostname);
 224                                 return false;
 225                         }
 226
 227                         inlen = 0;
 228 #endif
 229                 }
 230
 231                 while(c->inbuf.len) {
 232                         /* Are we receiving a TCPpacket? */
 233
 234                         if(c->tcplen) {
 235                                 char *tcpbuffer = buffer_read(&c->inbuf, c->tcplen);
 236                                 if(!tcpbuffer)
 237                                         break;
 238
 239                                 if(!c->node) {
 240                                         if(c->outgoing && proxytype == PROXY_SOCKS4 && c->allow_request == ID) {
 241                                                 if(tcpbuffer[0] == 0 && tcpbuffer[1] == 0x5a) {
 242                                                         logger(DEBUG_CONNECTIONS, LOG_DEBUG, "Proxy request granted");
 243                                                 } else {
 244                                                         logger(DEBUG_CONNECTIONS, LOG_ERR, "Proxy request rejected");
 245                                                         return false;
 246                                                 }
 247                                         } else if(c->outgoing && proxytype == PROXY_SOCKS5 && c->allow_request == ID) {
 248                                                 if(tcpbuffer[0] != 5) {
 249                                                         logger(DEBUG_CONNECTIONS, LOG_ERR, "Invalid response from proxy server");
 250                                                         return false;
 251                                                 }
 252                                                 if(tcpbuffer[1] == (char)0xff) {
 253                                                         logger(DEBUG_CONNECTIONS, LOG_ERR, "Proxy request rejected: unsuitable authentication method");
 254                                                         return false;
 255                                                 }
 256                                                 if(tcpbuffer[2] != 5) {
 257                                                         logger(DEBUG_CONNECTIONS, LOG_ERR, "Invalid response from proxy server");
 258                                                         return false;
 259                                                 }
 260                                                 if(tcpbuffer[3] == 0) {
 261                                                         logger(DEBUG_CONNECTIONS, LOG_DEBUG, "Proxy request granted");
 262                                                 } else {
 263                                                         logger(DEBUG_CONNECTIONS, LOG_DEBUG, "Proxy request rejected");
 264                                                         return false;
 265                                                 }
 266                                         } else {
 267                                                 logger(DEBUG_CONNECTIONS, LOG_ERR, "c->tcplen set but c->node is NULL!");
 268                                                 abort();
 269                                         }
 270                                 } else {
 271                                         if(c->allow_request == ALL) {
 272                                                 receive_tcppacket(c, tcpbuffer, c->tcplen);
 273                                         } else {
 274                                                 logger(DEBUG_CONNECTIONS, LOG_ERR, "Got unauthorized TCP packet from %s (%s)", c->name, c->hostname);
 275                                                 return false;
 276                                         }
 277                                 }
 278
 279                                 c->tcplen = 0;
 280                         }
 281
 282                         /* Otherwise we are waiting for a request */
 283
 284                         char *request = buffer_readline(&c->inbuf);
 285                         if(request) {
 286                                 bool result = receive_request(c, request);
 287                                 if(!result)
 288                                         return false;
 289                                 continue;
 290                         } else {
 291                                 break;
 292                         }
 293                 }
 294         } while(inlen);
 295
 296         return true;
 297 }