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         if(!c) {
  39                 logger(LOG_ERR, _("send_meta() called with NULL pointer!"));
  40                 abort();
  41         }
  42
  43         ifdebug(META) logger(LOG_DEBUG, _("Sending %d bytes of metadata to %s (%s)"), length,
  44                            c->name, c->hostname);
  45
  46         /* Add our data to buffer */
  47         if(c->status.encryptout) {
  48                 char outbuf[length];
  49                 size_t outlen = length;
  50
  51                 if(!cipher_encrypt(&c->outcipher, buffer, length, outbuf, &outlen, false) || outlen != length) {
  52                         logger(LOG_ERR, _("Error while encrypting metadata to %s (%s)"),
  53                                         c->name, c->hostname);
  54                         return false;
  55                 }
  56
  57                 ifdebug(META) logger(LOG_DEBUG, _("Encrypted write %p %p %p %d"), c, c->buffer, outbuf, length);
  58                 bufferevent_write(c->buffer, (void *)outbuf, length);
  59                 ifdebug(META) logger(LOG_DEBUG, _("Done."));
  60         } else {
  61                 ifdebug(META) logger(LOG_DEBUG, _("Unencrypted write %p %p %p %d"), c, c->buffer, buffer, length);
  62                 bufferevent_write(c->buffer, (void *)buffer, length);
  63                 ifdebug(META) logger(LOG_DEBUG, _("Done."));
  64         }
  65
  66         return true;
  67 }
  68
  69 void broadcast_meta(connection_t *from, const char *buffer, int length) {
  70         splay_node_t *node;
  71         connection_t *c;
  72
  73         cp();
  74
  75         for(node = connection_tree->head; node; node = node->next) {
  76                 c = node->data;
  77
  78                 if(c != from && c->status.active)
  79                         send_meta(c, buffer, length);
  80         }
  81 }
  82
  83 bool receive_meta(connection_t *c) {
  84         size_t inlen;
  85         char inbuf[MAXBUFSIZE];
  86         char *bufp = inbuf, *endp;
  87
  88         cp();
  89
  90         /* Strategy:
  91            - Read as much as possible from the TCP socket in one go.
  92            - Decrypt it.
  93            - Check if a full request is in the input buffer.
  94            - If yes, process request and remove it from the buffer,
  95            then check again.
  96            - If not, keep stuff in buffer and exit.
  97          */
  98
  99         inlen = recv(c->socket, inbuf, sizeof inbuf, 0);
 100
 101         if(inlen <= 0) {
 102                 logger(LOG_ERR, _("Receive callback called for %s (%s) but no data to receive: %s"), c->name, c->hostname, strerror(errno));
 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 %zu 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         c->last_ping_time = time(NULL);
 163
 164         return true;
 165 }