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 broadcast_meta(connection_t *from, const char *buffer, int length) {
  82         for list_each(connection_t, c, connection_list)
  83                 if(c != from && c->edge)
  84                         send_meta(c, buffer, length);
  85 }
  86
  87 bool receive_meta_sptps(void *handle, uint8_t type, const void *vdata, uint16_t length) {
  88         const char *data = vdata;
  89         connection_t *c = handle;
  90
  91         if(!c) {
  92                 logger(DEBUG_ALWAYS, LOG_ERR, "receive_meta_sptps() called with NULL pointer!");
  93                 abort();
  94         }
  95
  96         if(type == SPTPS_HANDSHAKE) {
  97                 if(c->allow_request == ACK)
  98                         return send_ack(c);
  99                 else
 100                         return true;
 101         }
 102
 103         if(!data)
 104                 return true;
 105
 106         /* Are we receiving a TCPpacket? */
 107
 108         if(c->tcplen) {
 109                 if(length != c->tcplen)
 110                         return false;
 111                 receive_tcppacket(c, data, length);
 112                 c->tcplen = 0;
 113                 return true;
 114         }
 115
 116         /* Change newline to null byte, just like non-SPTPS requests */
 117
 118         if(data[length - 1] == '\n')
 119                 ((char *)data)[length - 1] = 0;
 120
 121         /* Otherwise we are waiting for a request */
 122
 123         return receive_request(c, data);
 124 }
 125
 126 bool receive_meta(connection_t *c) {
 127         int inlen;
 128         char inbuf[MAXBUFSIZE];
 129         char *bufp = inbuf, *endp;
 130
 131         /* Strategy:
 132            - Read as much as possible from the TCP socket in one go.
 133            - Decrypt it.
 134            - Check if a full request is in the input buffer.
 135            - If yes, process request and remove it from the buffer,
 136            then check again.
 137            - If not, keep stuff in buffer and exit.
 138          */
 139
 140         buffer_compact(&c->inbuf, MAXBUFSIZE);
 141
 142         if(sizeof inbuf <= c->inbuf.len) {
 143                 logger(DEBUG_ALWAYS, LOG_ERR, "Input buffer full for %s (%s)", c->name, c->hostname);
 144                 return false;
 145         }
 146
 147         inlen = recv(c->socket, inbuf, sizeof inbuf - c->inbuf.len, 0);
 148
 149         if(inlen <= 0) {
 150                 if(!inlen || !sockerrno) {
 151                         logger(DEBUG_CONNECTIONS, LOG_NOTICE, "Connection closed by %s (%s)",
 152                                            c->name, c->hostname);
 153                 } else if(sockwouldblock(sockerrno))
 154                         return true;
 155                 else
 156                         logger(DEBUG_ALWAYS, LOG_ERR, "Metadata socket read error for %s (%s): %s",
 157                                    c->name, c->hostname, sockstrerror(sockerrno));
 158                 return false;
 159         }
 160
 161         do {
 162                 if(c->protocol_minor >= 2) {
 163                         int len = sptps_receive_data(&c->sptps, bufp, inlen);
 164                         if(!len)
 165                                 return false;
 166                         bufp += len;
 167                         inlen -= len;
 168                         continue;
 169                 }
 170
 171                 if(!c->status.decryptin) {
 172                         endp = memchr(bufp, '\n', inlen);
 173                         if(endp)
 174                                 endp++;
 175                         else
 176                                 endp = bufp + inlen;
 177
 178                         buffer_add(&c->inbuf, bufp, endp - bufp);
 179
 180                         inlen -= endp - bufp;
 181                         bufp = endp;
 182                 } else {
 183 #ifdef DISABLE_LEGACY
 184                         return false;
 185 #else
 186                         size_t outlen = inlen;
 187
 188                         if(!cipher_decrypt(c->incipher, bufp, inlen, buffer_prepare(&c->inbuf, inlen), &outlen, false) || inlen != outlen) {
 189                                 logger(DEBUG_ALWAYS, LOG_ERR, "Error while decrypting metadata from %s (%s)",
 190                                            c->name, c->hostname);
 191                                 return false;
 192                         }
 193
 194                         inlen = 0;
 195 #endif
 196                 }
 197
 198                 while(c->inbuf.len) {
 199                         /* Are we receiving a TCPpacket? */
 200
 201                         if(c->tcplen) {
 202                                 char *tcpbuffer = buffer_read(&c->inbuf, c->tcplen);
 203                                 if(!tcpbuffer)
 204                                         break;
 205
 206                                 if(!c->node) {
 207                                         if(c->outgoing && proxytype == PROXY_SOCKS4 && c->allow_request == ID) {
 208                                                 if(tcpbuffer[0] == 0 && tcpbuffer[1] == 0x5a) {
 209                                                         logger(DEBUG_CONNECTIONS, LOG_DEBUG, "Proxy request granted");
 210                                                 } else {
 211                                                         logger(DEBUG_CONNECTIONS, LOG_ERR, "Proxy request rejected");
 212                                                         return false;
 213                                                 }
 214                                         } else if(c->outgoing && proxytype == PROXY_SOCKS5 && c->allow_request == ID) {
 215                                                 if(tcpbuffer[0] != 5) {
 216                                                         logger(DEBUG_CONNECTIONS, LOG_ERR, "Invalid response from proxy server");
 217                                                         return false;
 218                                                 }
 219                                                 if(tcpbuffer[1] == (char)0xff) {
 220                                                         logger(DEBUG_CONNECTIONS, LOG_ERR, "Proxy request rejected: unsuitable authentication method");
 221                                                         return false;
 222                                                 }
 223                                                 if(tcpbuffer[2] != 5) {
 224                                                         logger(DEBUG_CONNECTIONS, LOG_ERR, "Invalid response from proxy server");
 225                                                         return false;
 226                                                 }
 227                                                 if(tcpbuffer[3] == 0) {
 228                                                         logger(DEBUG_CONNECTIONS, LOG_DEBUG, "Proxy request granted");
 229                                                 } else {
 230                                                         logger(DEBUG_CONNECTIONS, LOG_DEBUG, "Proxy request rejected");
 231                                                         return false;
 232                                                 }
 233                                         } else {
 234                                                 logger(DEBUG_CONNECTIONS, LOG_ERR, "c->tcplen set but c->node is NULL!");
 235                                                 abort();
 236                                         }
 237                                 } else {
 238                                         if(c->allow_request == ALL) {
 239                                                 receive_tcppacket(c, tcpbuffer, c->tcplen);
 240                                         } else {
 241                                                 logger(DEBUG_CONNECTIONS, LOG_ERR, "Got unauthorized TCP packet from %s (%s)", c->name, c->hostname);
 242                                                 return false;
 243                                         }
 244                                 }
 245
 246                                 c->tcplen = 0;
 247                         }
 248
 249                         /* Otherwise we are waiting for a request */
 250
 251                         char *request = buffer_readline(&c->inbuf);
 252                         if(request) {
 253                                 bool result = receive_request(c, request);
 254                                 if(!result)
 255                                         return false;
 256                                 continue;
 257                         } else {
 258                                 break;
 259                         }
 260                 }
 261         } while(inlen);
 262
 263         return true;
 264 }