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                 write(c->socket, outbuf, length);
  55         } else {
  56                 write(c->socket, buffer, length);
  57         }
  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 static bool process_meta(connection_t *c, char *reqbuf, int *len) {
  75         while(*len) {
  76                 if(c->tcplen) {
  77                         if(c->tcplen > *len)
  78                                 break;
  79
  80                         mutex_lock(&mutex);
  81                         receive_tcppacket(c, reqbuf, c->tcplen);
  82                         mutex_unlock(&mutex);
  83
  84                         memmove(reqbuf, reqbuf, *len - c->tcplen);
  85                         *len -= c->tcplen;
  86                 } else {
  87                         char *end = memchr(reqbuf, '\n', *len);
  88                         if(!end)
  89                                 break;
  90                         else
  91                                 *end++ = 0;
  92
  93                         mutex_lock(&mutex);
  94                         bool success = receive_request(c, reqbuf);
  95                         mutex_unlock(&mutex);
  96
  97                         if(!success)
  98                                 return false;
  99
 100                         memmove(reqbuf, end, *len - (end - reqbuf));
 101                         *len -= end - reqbuf;
 102                 }
 103         }
 104
 105         return true;
 106 }
 107
 108 bool receive_meta(connection_t *c) {
 109         int inlen;
 110         int reqlen = 0;
 111         char inbuf[MAXBUFSIZE];
 112         char reqbuf[MAXBUFSIZE];
 113
 114         /* Strategy:
 115            - Read as much as possible from the TCP socket in one go.
 116            - Decrypt it if necessary.
 117            - Check if a full request is in the request buffer.
 118            - If yes, process request and remove it from the buffer, then check again.
 119            - If not, try to read more.
 120          */
 121
 122         while(true) {
 123                 inlen = recv(c->socket, inbuf, sizeof inbuf - reqlen, 0);
 124
 125                 if(inlen <= 0) {
 126                         if(!inlen || !errno) {
 127                                 ifdebug(CONNECTIONS) logger(LOG_NOTICE, "Connection closed by %s (%s)",
 128                                                    c->name, c->hostname);
 129                         } else if(sockwouldblock(sockerrno))
 130                                 continue;
 131                         else
 132                                 logger(LOG_ERR, "Metadata socket read error for %s (%s): %s",
 133                                            c->name, c->hostname, sockstrerror(sockerrno));
 134                         return false;
 135                 }
 136
 137                 while(inlen) {
 138                         if(!c->status.decryptin) {
 139                                 char *end = memchr(inbuf, '\n', inlen);
 140                                 if(!end)
 141                                         end = inbuf + inlen;
 142                                 else
 143                                         end++;
 144                                 memcpy(reqbuf + reqlen, inbuf, end - inbuf);
 145                                 reqlen += end - inbuf;
 146
 147                                 if(!process_meta(c, reqbuf, &reqlen))
 148                                         return false;
 149
 150                                 memmove(inbuf, end, inlen - (end - inbuf));
 151                                 inlen -= end - inbuf;
 152                         } else {
 153                                 size_t outlen = inlen;
 154
 155                                 if(!cipher_decrypt(&c->incipher, inbuf, inlen, reqbuf + reqlen, &outlen, false) || inlen != outlen) {
 156                                         logger(LOG_ERR, "Error while decrypting metadata from %s (%s)", c->name, c->hostname);
 157                                         return false;
 158                                 }
 159
 160                                 reqlen += inlen;
 161                                 inlen = 0;
 162
 163                                 if(!process_meta(c, reqbuf, &reqlen))
 164                                         return false;
 165                         }
 166                 }
 167         }
 168 }