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 <openssl/err.h>
  26 #include <openssl/evp.h>
  27
  28 #include "splay_tree.h"
  29 #include "connection.h"
  30 #include "logger.h"
  31 #include "meta.h"
  32 #include "net.h"
  33 #include "protocol.h"
  34 #include "utils.h"
  35 #include "xalloc.h"
  36
  37 bool send_meta(connection_t *c, const char *buffer, int length) {
  38         int outlen;
  39         int result;
  40         cp();
  41
  42         ifdebug(META) logger(LOG_DEBUG, _("Sending %d bytes of metadata to %s (%s)"), length,
  43                            c->name, c->hostname);
  44
  45         /* Add our data to buffer */
  46         if(c->status.encryptout) {
  47                 char outbuf[length];
  48
  49                 result = EVP_EncryptUpdate(c->outctx, (unsigned char *)outbuf, &outlen, (unsigned char *)buffer, length);
  50                 if(!result || outlen != length) {
  51                         logger(LOG_ERR, _("Error while encrypting metadata to %s (%s): %s"),
  52                                         c->name, c->hostname, ERR_error_string(ERR_get_error(), NULL));
  53                         return false;
  54                 }
  55
  56                 ifdebug(META) logger(LOG_DEBUG, _("Encrypted write %p %p %p %d"), c, c->buffer, outbuf, length);
  57                 bufferevent_write(c->buffer, (void *)outbuf, length);
  58                 ifdebug(META) logger(LOG_DEBUG, _("Done."));
  59         } else {
  60                 ifdebug(META) logger(LOG_DEBUG, _("Unencrypted write %p %p %p %d"), c, c->buffer, buffer, length);
  61                 bufferevent_write(c->buffer, (void *)buffer, length);
  62                 ifdebug(META) logger(LOG_DEBUG, _("Done."));
  63         }
  64
  65         return true;
  66 }
  67
  68 void broadcast_meta(connection_t *from, const char *buffer, int length) {
  69         splay_node_t *node;
  70         connection_t *c;
  71
  72         cp();
  73
  74         for(node = connection_tree->head; node; node = node->next) {
  75                 c = node->data;
  76
  77                 if(c != from && c->status.active)
  78                         send_meta(c, buffer, length);
  79         }
  80 }
  81
  82 bool receive_meta(connection_t *c) {
  83         int result, inlen, outlen;
  84         char inbuf[MAXBUFSIZE];
  85         char *bufp = inbuf, *endp;
  86
  87         cp();
  88
  89         /* Strategy:
  90            - Read as much as possible from the TCP socket in one go.
  91            - Decrypt it.
  92            - Check if a full request is in the input buffer.
  93            - If yes, process request and remove it from the buffer,
  94            then check again.
  95            - If not, keep stuff in buffer and exit.
  96          */
  97
  98         inlen = recv(c->socket, inbuf, sizeof inbuf, 0);
  99
 100         if(inlen <= 0) {
 101                 logger(LOG_ERR, _("Receive callback called for %s (%s) but no data to receive: %s"), c->name, c->hostname, strerror(errno));
 102                 return false;
 103         }
 104
 105         do {
 106                 if(!c->status.decryptin) {
 107                         endp = memchr(bufp, '\n', inlen);
 108                         if(endp)
 109                                 endp++;
 110                         else
 111                                 endp = bufp + inlen;
 112
 113                         evbuffer_add(c->buffer->input, bufp, endp - bufp);
 114
 115                         inlen -= endp - bufp;
 116                         bufp = endp;
 117                 } else {
 118                         ifdebug(META) logger(LOG_DEBUG, _("Received encrypted %d bytes"), inlen);
 119                         evbuffer_expand(c->buffer->input, c->buffer->input->off + inlen);
 120                         result = EVP_DecryptUpdate(c->inctx, (unsigned char *)c->buffer->input->buffer + c->buffer->input->off, &outlen, (unsigned char *)bufp, inlen);
 121                         if(!result || outlen != inlen) {
 122                                 logger(LOG_ERR, _("Error while decrypting metadata from %s (%s): %s"),
 123                                            c->name, c->hostname, ERR_error_string(ERR_get_error(), NULL));
 124                                 return false;
 125                         }
 126                         c->buffer->input->off += inlen;
 127
 128                         inlen = 0;
 129                 }
 130
 131                 while(c->buffer->input->off) {
 132                         /* Are we receiving a TCPpacket? */
 133
 134                         if(c->tcplen) {
 135                                 if(c->tcplen <= c->buffer->input->off) {
 136                                         receive_tcppacket(c, (char *)c->buffer->input->buffer, c->tcplen);
 137                                         evbuffer_drain(c->buffer->input, c->tcplen);
 138                                         c->tcplen = 0;
 139                                         continue;
 140                                 } else {
 141                                         break;
 142                                 }
 143                         }
 144
 145                         /* Otherwise we are waiting for a request */
 146
 147                         char *request = evbuffer_readline(c->buffer->input);
 148                         if(request) {
 149                                 receive_request(c, request);
 150                                 free(request);
 151                                 continue;
 152                         } else {
 153                                 break;
 154                         }
 155                 }
 156         } while(inlen);
 157
 158         c->last_ping_time = time(NULL);
 159
 160         return true;
 161 }