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

   1 /*
   2     meta.c -- handle the meta communication
   3     Copyright (C) 2000-2009 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 "splay_tree.h"
  25 #include "cipher.h"
  26 #include "connection.h"
  27 #include "logger.h"
  28 #include "meta.h"
  29 #include "net.h"
  30 #include "protocol.h"
  31 #include "utils.h"
  32 #include "xalloc.h"
  33
  34 bool send_meta(connection_t *c, const char *buffer, int length) {
  35         if(!c) {
  36                 logger(LOG_ERR, "send_meta() called with NULL pointer!");
  37                 abort();
  38         }
  39
  40         ifdebug(META) logger(LOG_DEBUG, "Sending %d bytes of metadata to %s (%s)", length,
  41                            c->name, c->hostname);
  42
  43         /* Add our data to buffer */
  44         if(c->status.encryptout) {
  45                 char outbuf[length];
  46                 size_t outlen = length;
  47
  48                 if(!cipher_encrypt(&c->outcipher, buffer, length, outbuf, &outlen, false) || outlen != length) {
  49                         logger(LOG_ERR, "Error while encrypting metadata to %s (%s)",
  50                                         c->name, c->hostname);
  51                         return false;
  52                 }
  53
  54                 ifdebug(META) logger(LOG_DEBUG, "Encrypted write %p %p %p %d", c, c->buffer, outbuf, length);
  55                 bufferevent_write(c->buffer, (void *)outbuf, length);
  56                 ifdebug(META) logger(LOG_DEBUG, "Done.");
  57         } else {
  58                 ifdebug(META) logger(LOG_DEBUG, "Unencrypted write %p %p %p %d", c, c->buffer, buffer, length);
  59                 bufferevent_write(c->buffer, (void *)buffer, length);
  60                 ifdebug(META) logger(LOG_DEBUG, "Done.");
  61         }
  62
  63         return true;
  64 }
  65
  66 void broadcast_meta(connection_t *from, const char *buffer, int length) {
  67         splay_node_t *node;
  68         connection_t *c;
  69
  70         for(node = connection_tree->head; node; node = node->next) {
  71                 c = node->data;
  72
  73                 if(c != from && c->status.active)
  74                         send_meta(c, buffer, length);
  75         }
  76 }
  77
  78 bool receive_meta(connection_t *c) {
  79         int inlen;
  80         char inbuf[MAXBUFSIZE];
  81         char *bufp = inbuf, *endp;
  82
  83         /* Strategy:
  84            - Read as much as possible from the TCP socket in one go.
  85            - Decrypt it.
  86            - Check if a full request is in the input buffer.
  87            - If yes, process request and remove it from the buffer,
  88            then check again.
  89            - If not, keep stuff in buffer and exit.
  90          */
  91
  92         inlen = recv(c->socket, inbuf, sizeof inbuf, 0);
  93
  94         if(inlen <= 0) {
  95                 if(!inlen || !errno) {
  96                         ifdebug(CONNECTIONS) logger(LOG_NOTICE, "Connection closed by %s (%s)",
  97                                            c->name, c->hostname);
  98                 } else if(sockwouldblock(sockerrno))
  99                         return true;
 100                 else
 101                         logger(LOG_ERR, "Metadata socket read error for %s (%s): %s",
 102                                    c->name, c->hostname, sockstrerror(sockerrno));
 103                 return false;
 104         }
 105
 106         do {
 107                 if(!c->status.decryptin) {
 108                         endp = memchr(bufp, '\n', inlen);
 109                         if(endp)
 110                                 endp++;
 111                         else
 112                                 endp = bufp + inlen;
 113
 114                         evbuffer_add(c->buffer->input, bufp, endp - bufp);
 115
 116                         inlen -= endp - bufp;
 117                         bufp = endp;
 118                 } else {
 119                         size_t outlen = inlen;
 120                         ifdebug(META) logger(LOG_DEBUG, "Received encrypted %d bytes", inlen);
 121                         evbuffer_expand(c->buffer->input, c->buffer->input->off + inlen);
 122
 123                         if(!cipher_decrypt(&c->incipher, bufp, inlen, c->buffer->input->buffer + c->buffer->input->off, &outlen, false) || inlen != outlen) {
 124                                 logger(LOG_ERR, "Error while decrypting metadata from %s (%s)",
 125                                            c->name, c->hostname);
 126                                 return false;
 127                         }
 128                         c->buffer->input->off += inlen;
 129
 130                         inlen = 0;
 131                 }
 132
 133                 while(c->buffer->input->off) {
 134                         /* Are we receiving a TCPpacket? */
 135
 136                         if(c->tcplen) {
 137                                 if(c->tcplen <= c->buffer->input->off) {
 138                                         receive_tcppacket(c, (char *)c->buffer->input->buffer, c->tcplen);
 139                                         evbuffer_drain(c->buffer->input, c->tcplen);
 140                                         c->tcplen = 0;
 141                                         continue;
 142                                 } else {
 143                                         break;
 144                                 }
 145                         }
 146
 147                         /* Otherwise we are waiting for a request */
 148
 149                         char *request = evbuffer_readline(c->buffer->input);
 150                         if(request) {
 151                                 bool result = receive_request(c, request);
 152                                 free(request);
 153                                 if(!result)
 154                                         return false;
 155                                 continue;
 156                         } else {
 157                                 break;
 158                         }
 159                 }
 160         } while(inlen);
 161
 162         return true;
 163 }