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

   1 /*
   2     meta.c -- handle the meta communication
   3     Copyright (C) 2000-2018 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 <assert.h>
  25
  26 #include "cipher.h"
  27 #include "connection.h"
  28 #include "logger.h"
  29 #include "meta.h"
  30 #include "net.h"
  31 #include "protocol.h"
  32 #include "utils.h"
  33 #include "proxy.h"
  34
  35 #ifndef MIN
  36 static ssize_t MIN(ssize_t x, ssize_t y) {
  37         return x < y ? x : y;
  38 }
  39 #endif
  40
  41 bool send_meta_sptps(void *handle, uint8_t type, const void *buffer, size_t length) {
  42         (void)type;
  43         connection_t *c = handle;
  44
  45         if(!c) {
  46                 logger(DEBUG_ALWAYS, LOG_ERR, "send_meta_sptps() called with NULL pointer!");
  47                 abort();
  48         }
  49
  50         buffer_add(&c->outbuf, buffer, length);
  51         io_set(&c->io, IO_READ | IO_WRITE);
  52
  53         return true;
  54 }
  55
  56 bool send_meta(connection_t *c, const void *buffer, size_t length) {
  57         if(!c) {
  58                 logger(DEBUG_ALWAYS, LOG_ERR, "send_meta() called with NULL pointer!");
  59                 abort();
  60         }
  61
  62         logger(DEBUG_META, LOG_DEBUG, "Sending %lu bytes of metadata to %s (%s)",
  63                (unsigned long)length, c->name, c->hostname);
  64
  65         if(c->protocol_minor >= 2) {
  66                 return sptps_send_record(&c->sptps, 0, buffer, length);
  67         }
  68
  69         /* Add our data to buffer */
  70         if(c->status.encryptout) {
  71 #ifdef DISABLE_LEGACY
  72                 return false;
  73 #else
  74                 assert(c->legacy);
  75
  76                 if(!decrease_budget(&c->legacy->out, length)) {
  77                         logger(DEBUG_META, LOG_ERR, "Byte limit exceeded for encryption to %s (%s)", c->name, c->hostname);
  78                         return false;
  79                 }
  80
  81                 size_t outlen = length;
  82
  83                 if(!cipher_encrypt(&c->legacy->out.cipher, buffer, length, buffer_prepare(&c->outbuf, length), &outlen, false) || outlen != length) {
  84                         logger(DEBUG_ALWAYS, LOG_ERR, "Error while encrypting metadata to %s (%s)",
  85                                c->name, c->hostname);
  86                         return false;
  87                 }
  88
  89 #endif
  90         } else {
  91                 buffer_add(&c->outbuf, buffer, length);
  92         }
  93
  94         io_set(&c->io, IO_READ | IO_WRITE);
  95
  96         return true;
  97 }
  98
  99 void send_meta_raw(connection_t *c, const void *buffer, size_t length) {
 100         if(!c) {
 101                 logger(DEBUG_ALWAYS, LOG_ERR, "send_meta() called with NULL pointer!");
 102                 abort();
 103         }
 104
 105         logger(DEBUG_META, LOG_DEBUG, "Sending %lu bytes of raw metadata to %s (%s)",
 106                (unsigned long)length, c->name, c->hostname);
 107
 108         buffer_add(&c->outbuf, buffer, length);
 109
 110         io_set(&c->io, IO_READ | IO_WRITE);
 111 }
 112
 113 void broadcast_meta(connection_t *from, const char *buffer, size_t length) {
 114         for list_each(connection_t, c, &connection_list)
 115                 if(c != from && c->edge) {
 116                         send_meta(c, buffer, length);
 117                 }
 118 }
 119
 120 bool receive_meta_sptps(void *handle, uint8_t type, const void *vdata, uint16_t length) {
 121         const char *data = vdata;
 122         connection_t *c = handle;
 123
 124         if(!c) {
 125                 logger(DEBUG_ALWAYS, LOG_ERR, "receive_meta_sptps() called with NULL pointer!");
 126                 abort();
 127         }
 128
 129         if(type == SPTPS_HANDSHAKE) {
 130                 if(c->allow_request == ACK) {
 131                         return send_ack(c);
 132                 } else {
 133                         return true;
 134                 }
 135         }
 136
 137         if(!data) {
 138                 return true;
 139         }
 140
 141         /* Are we receiving a TCPpacket? */
 142
 143         if(c->tcplen) {
 144                 if(length != c->tcplen) {
 145                         return false;
 146                 }
 147
 148                 receive_tcppacket(c, data, length);
 149                 c->tcplen = 0;
 150                 return true;
 151         }
 152
 153         /* Change newline to null byte, just like non-SPTPS requests */
 154
 155         if(data[length - 1] == '\n') {
 156                 ((char *)data)[length - 1] = 0;
 157         }
 158
 159         /* Otherwise we are waiting for a request */
 160
 161         return receive_request(c, data);
 162 }
 163
 164 bool receive_meta(connection_t *c) {
 165         ssize_t inlen;
 166         char inbuf[MAXBUFSIZE];
 167         char *bufp = inbuf, *endp;
 168
 169         /* Strategy:
 170            - Read as much as possible from the TCP socket in one go.
 171            - Decrypt it.
 172            - Check if a full request is in the input buffer.
 173            - If yes, process request and remove it from the buffer,
 174            then check again.
 175            - If not, keep stuff in buffer and exit.
 176          */
 177
 178         buffer_compact(&c->inbuf, MAXBUFSIZE);
 179
 180         if(sizeof(inbuf) <= c->inbuf.len) {
 181                 logger(DEBUG_ALWAYS, LOG_ERR, "Input buffer full for %s (%s)", c->name, c->hostname);
 182                 return false;
 183         }
 184
 185         inlen = recv(c->socket, inbuf, sizeof(inbuf) - c->inbuf.len, 0);
 186
 187         if(inlen <= 0) {
 188                 if(!inlen || !sockerrno) {
 189                         logger(DEBUG_CONNECTIONS, LOG_NOTICE, "Connection closed by %s (%s)",
 190                                c->name, c->hostname);
 191                 } else if(sockwouldblock(sockerrno)) {
 192                         return true;
 193                 } else
 194                         logger(DEBUG_ALWAYS, LOG_ERR, "Metadata socket read error for %s (%s): %s",
 195                                c->name, c->hostname, sockstrerror(sockerrno));
 196
 197                 return false;
 198         }
 199
 200         do {
 201                 /* Are we receiving a SPTPS packet? */
 202
 203                 if(c->sptpslen) {
 204                         ssize_t len = MIN(inlen, c->sptpslen - c->inbuf.len);
 205                         buffer_add(&c->inbuf, bufp, len);
 206
 207                         char *sptpspacket = buffer_read(&c->inbuf, c->sptpslen);
 208
 209                         if(!sptpspacket) {
 210                                 return true;
 211                         }
 212
 213                         if(!receive_tcppacket_sptps(c, sptpspacket, c->sptpslen)) {
 214                                 return false;
 215                         }
 216
 217                         c->sptpslen = 0;
 218
 219                         bufp += len;
 220                         inlen -= len;
 221                         continue;
 222                 }
 223
 224                 if(c->protocol_minor >= 2) {
 225                         size_t len = sptps_receive_data(&c->sptps, bufp, inlen);
 226
 227                         if(!len) {
 228                                 return false;
 229                         }
 230
 231                         bufp += len;
 232                         inlen -= (ssize_t)len;
 233                         continue;
 234                 }
 235
 236                 if(!c->status.decryptin) {
 237                         endp = memchr(bufp, '\n', inlen);
 238
 239                         if(endp) {
 240                                 endp++;
 241                         } else {
 242                                 endp = bufp + inlen;
 243                         }
 244
 245                         buffer_add(&c->inbuf, bufp, endp - bufp);
 246
 247                         inlen -= endp - bufp;
 248                         bufp = endp;
 249                 } else {
 250 #ifdef DISABLE_LEGACY
 251                         return false;
 252 #else
 253                         assert(c->legacy);
 254
 255                         if(!decrease_budget(&c->legacy->in, (size_t) inlen)) {
 256                                 logger(DEBUG_META, LOG_ERR, "Byte limit exceeded for decryption from %s (%s)", c->name, c->hostname);
 257                                 return false;
 258                         }
 259
 260                         size_t outlen = inlen;
 261
 262                         if(!cipher_decrypt(&c->legacy->in.cipher, bufp, inlen, buffer_prepare(&c->inbuf, inlen), &outlen, false) || (size_t)inlen != outlen) {
 263                                 logger(DEBUG_ALWAYS, LOG_ERR, "Error while decrypting metadata from %s (%s)",
 264                                        c->name, c->hostname);
 265                                 return false;
 266                         }
 267
 268                         inlen = 0;
 269 #endif
 270                 }
 271
 272                 while(c->inbuf.len) {
 273                         /* Are we receiving a TCPpacket? */
 274
 275                         if(c->tcplen) {
 276                                 char *tcpbuffer = buffer_read(&c->inbuf, c->tcplen);
 277
 278                                 if(!tcpbuffer) {
 279                                         break;
 280                                 }
 281
 282                                 if(!c->node) {
 283                                         if(c->outgoing && c->allow_request == ID && (proxytype == PROXY_SOCKS4 || proxytype == PROXY_SOCKS5)) {
 284                                                 if(!check_socks_resp(proxytype, tcpbuffer, c->tcplen)) {
 285                                                         return false;
 286                                                 }
 287                                         } else {
 288                                                 logger(DEBUG_CONNECTIONS, LOG_ERR, "c->tcplen set but c->node is NULL!");
 289                                                 abort();
 290                                         }
 291                                 } else {
 292                                         if(c->allow_request == ALL) {
 293                                                 receive_tcppacket(c, tcpbuffer, c->tcplen);
 294                                         } else {
 295                                                 logger(DEBUG_CONNECTIONS, LOG_ERR, "Got unauthorized TCP packet from %s (%s)", c->name, c->hostname);
 296                                                 return false;
 297                                         }
 298                                 }
 299
 300                                 c->tcplen = 0;
 301                         }
 302
 303                         /* Otherwise we are waiting for a request */
 304
 305                         char *request = buffer_readline(&c->inbuf);
 306
 307                         if(request) {
 308                                 bool result = receive_request(c, request);
 309
 310                                 if(!result) {
 311                                         return false;
 312                                 }
 313
 314                                 continue;
 315                         } else {
 316                                 break;
 317                         }
 318                 }
 319         } while(inlen);
 320
 321         return true;
 322 }