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