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                 size_t outlen = length;
  46
  47                 if(!cipher_encrypt(&c->outcipher, buffer, length, buffer_prepare(&c->outbuf, length), &outlen, false) || outlen != length) {
  48                         logger(LOG_ERR, "Error while encrypting metadata to %s (%s)",
  49                                         c->name, c->hostname);
  50                         return false;
  51                 }
  52
  53         } else {
  54                 buffer_add(&c->outbuf, buffer, length);
  55         }
  56
  57         event_add(&c->outevent, NULL);
  58
  59         return true;
  60 }
  61
  62 void broadcast_meta(connection_t *from, const char *buffer, int length) {
  63         splay_node_t *node;
  64         connection_t *c;
  65
  66         for(node = connection_tree->head; node; node = node->next) {
  67                 c = node->data;
  68
  69                 if(c != from && c->status.active)
  70                         send_meta(c, buffer, length);
  71         }
  72 }
  73
  74 bool receive_meta(connection_t *c) {
  75         int inlen;
  76         char inbuf[MAXBUFSIZE];
  77         char *bufp = inbuf, *endp;
  78
  79         /* Strategy:
  80            - Read as much as possible from the TCP socket in one go.
  81            - Decrypt it.
  82            - Check if a full request is in the input buffer.
  83            - If yes, process request and remove it from the buffer,
  84            then check again.
  85            - If not, keep stuff in buffer and exit.
  86          */
  87
  88         buffer_compact(&c->inbuf, MAXBUFSIZE);
  89
  90         if(sizeof inbuf <= c->inbuf.len) {
  91                 logger(LOG_ERR, "Input buffer full for %s (%s)\n", c, c->hostname);
  92                 return false;
  93         }
  94
  95         inlen = recv(c->socket, inbuf, sizeof inbuf - c->inbuf.len, 0);
  96
  97         if(inlen <= 0) {
  98                 if(!inlen || !errno) {
  99                         ifdebug(CONNECTIONS) logger(LOG_NOTICE, "Connection closed by %s (%s)",
 100                                            c->name, c->hostname);
 101                 } else if(sockwouldblock(sockerrno))
 102                         return true;
 103                 else
 104                         logger(LOG_ERR, "Metadata socket read error for %s (%s): %s",
 105                                    c->name, c->hostname, sockstrerror(sockerrno));
 106                 return false;
 107         }
 108
 109         do {
 110                 if(!c->status.decryptin) {
 111                         endp = memchr(bufp, '\n', inlen);
 112                         if(endp)
 113                                 endp++;
 114                         else
 115                                 endp = bufp + inlen;
 116
 117                         buffer_add(&c->inbuf, bufp, endp - bufp);
 118
 119                         inlen -= endp - bufp;
 120                         bufp = endp;
 121                 } else {
 122                         size_t outlen = inlen;
 123                         ifdebug(META) logger(LOG_DEBUG, "Received encrypted %d bytes", inlen);
 124
 125                         if(!cipher_decrypt(&c->incipher, bufp, inlen, buffer_prepare(&c->inbuf, inlen), &outlen, false) || inlen != outlen) {
 126                                 logger(LOG_ERR, "Error while decrypting metadata from %s (%s)",
 127                                            c->name, c->hostname);
 128                                 return false;
 129                         }
 130
 131                         inlen = 0;
 132                 }
 133
 134                 while(c->inbuf.len) {
 135                         /* Are we receiving a TCPpacket? */
 136
 137                         if(c->tcplen) {
 138                                 char *tcpbuffer = buffer_read(&c->inbuf, c->tcplen);
 139                                 if(tcpbuffer) {
 140                                         c->tcplen = 0;
 141                                         receive_tcppacket(c, tcpbuffer, c->tcplen);
 142                                         continue;
 143                                 } else {
 144                                         break;
 145                                 }
 146                         }
 147
 148                         /* Otherwise we are waiting for a request */
 149
 150                         char *request = buffer_readline(&c->inbuf);
 151                         if(request) {
 152                                 bool result = receive_request(c, request);
 153                                 if(!result)
 154                                         return false;
 155                                 continue;
 156                         } else {
 157                                 break;
 158                         }
 159                 }
 160         } while(inlen);
 161
 162         return true;
 163 }