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

   1 /*
   2     meta.c -- handle the meta communication
   3     Copyright (C) 2000-2006 Guus Sliepen <guus@tinc-vpn.org>,
   4                   2000-2005 Ivo Timmermans
   5
   6     This program is free software; you can redistribute it and/or modify
   7     it under the terms of the GNU General Public License as published by
   8     the Free Software Foundation; either version 2 of the License, or
   9     (at your option) any later version.
  10
  11     This program is distributed in the hope that it will be useful,
  12     but WITHOUT ANY WARRANTY; without even the implied warranty of
  13     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14     GNU General Public License for more details.
  15
  16     You should have received a copy of the GNU General Public License
  17     along with this program; if not, write to the Free Software
  18     Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  19
  20     $Id$
  21 */
  22
  23 #include "system.h"
  24
  25 #include "splay_tree.h"
  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 "xalloc.h"
  34
  35 bool send_meta(connection_t *c, const char *buffer, int length) {
  36         cp();
  37
  38         ifdebug(META) logger(LOG_DEBUG, _("Sending %d bytes of metadata to %s (%s)"), length,
  39                            c->name, c->hostname);
  40
  41         /* Add our data to buffer */
  42         if(c->status.encryptout) {
  43                 char outbuf[length];
  44                 size_t outlen = length;
  45
  46                 if(!cipher_encrypt(&c->outcipher, buffer, length, outbuf, &outlen, false) || outlen != length) {
  47                         logger(LOG_ERR, _("Error while encrypting metadata to %s (%s)"),
  48                                         c->name, c->hostname);
  49                         return false;
  50                 }
  51
  52                 ifdebug(META) logger(LOG_DEBUG, _("Encrypted write %p %p %p %d"), c, c->buffer, outbuf, length);
  53                 bufferevent_write(c->buffer, (void *)outbuf, length);
  54                 ifdebug(META) logger(LOG_DEBUG, _("Done."));
  55         } else {
  56                 ifdebug(META) logger(LOG_DEBUG, _("Unencrypted write %p %p %p %d"), c, c->buffer, buffer, length);
  57                 bufferevent_write(c->buffer, (void *)buffer, length);
  58                 ifdebug(META) logger(LOG_DEBUG, _("Done."));
  59         }
  60
  61         return true;
  62 }
  63
  64 void broadcast_meta(connection_t *from, const char *buffer, int length) {
  65         splay_node_t *node;
  66         connection_t *c;
  67
  68         cp();
  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         size_t inlen;
  80         char inbuf[MAXBUFSIZE];
  81         char *bufp = inbuf, *endp;
  82
  83         cp();
  84
  85         /* Strategy:
  86            - Read as much as possible from the TCP socket in one go.
  87            - Decrypt it.
  88            - Check if a full request is in the input buffer.
  89            - If yes, process request and remove it from the buffer,
  90            then check again.
  91            - If not, keep stuff in buffer and exit.
  92          */
  93
  94         inlen = recv(c->socket, inbuf, sizeof inbuf, 0);
  95
  96         if(inlen <= 0) {
  97                 logger(LOG_ERR, _("Receive callback called for %s (%s) but no data to receive: %s"), c->name, c->hostname, strerror(errno));
  98                 return false;
  99         }
 100
 101         do {
 102                 if(!c->status.decryptin) {
 103                         endp = memchr(bufp, '\n', inlen);
 104                         if(endp)
 105                                 endp++;
 106                         else
 107                                 endp = bufp + inlen;
 108
 109                         evbuffer_add(c->buffer->input, bufp, endp - bufp);
 110
 111                         inlen -= endp - bufp;
 112                         bufp = endp;
 113                 } else {
 114                         size_t outlen = inlen;
 115                         ifdebug(META) logger(LOG_DEBUG, _("Received encrypted %zu bytes"), inlen);
 116                         evbuffer_expand(c->buffer->input, c->buffer->input->off + inlen);
 117
 118                         if(!cipher_decrypt(&c->incipher, bufp, inlen, c->buffer->input->buffer + c->buffer->input->off, &outlen, false) || inlen != outlen) {
 119                                 logger(LOG_ERR, _("Error while decrypting metadata from %s (%s)"),
 120                                            c->name, c->hostname);
 121                                 return false;
 122                         }
 123                         c->buffer->input->off += inlen;
 124
 125                         inlen = 0;
 126                 }
 127
 128                 while(c->buffer->input->off) {
 129                         /* Are we receiving a TCPpacket? */
 130
 131                         if(c->tcplen) {
 132                                 if(c->tcplen <= c->buffer->input->off) {
 133                                         receive_tcppacket(c, (char *)c->buffer->input->buffer, c->tcplen);
 134                                         evbuffer_drain(c->buffer->input, c->tcplen);
 135                                         c->tcplen = 0;
 136                                         continue;
 137                                 } else {
 138                                         break;
 139                                 }
 140                         }
 141
 142                         /* Otherwise we are waiting for a request */
 143
 144                         char *request = evbuffer_readline(c->buffer->input);
 145                         if(request) {
 146                                 bool result = receive_request(c, request);
 147                                 free(request);
 148                                 if(!result)
 149                                         return false;
 150                                 continue;
 151                         } else {
 152                                 break;
 153                         }
 154                 }
 155         } while(inlen);
 156
 157         c->last_ping_time = time(NULL);
 158
 159         return true;
 160 }