git.meshlink.io Git - meshlink/blob - src/meta.c

   1 /*
   2     meta.c -- handle the meta communication
   3     Copyright (C) 2014 Guus Sliepen <guus@meshlink.io>,
   4
   5     This program is free software; you can redistribute it and/or modify
   6     it under the terms of the GNU General Public License as published by
   7     the Free Software Foundation; either version 2 of the License, or
   8     (at your option) any later version.
   9
  10     This program is distributed in the hope that it will be useful,
  11     but WITHOUT ANY WARRANTY; without even the implied warranty of
  12     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13     GNU General Public License for more details.
  14
  15     You should have received a copy of the GNU General Public License along
  16     with this program; if not, write to the Free Software Foundation, Inc.,
  17     51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  18 */
  19
  20 #include "system.h"
  21
  22 #include "cipher.h"
  23 #include "connection.h"
  24 #include "logger.h"
  25 #include "meta.h"
  26 #include "net.h"
  27 #include "protocol.h"
  28 #include "utils.h"
  29 #include "xalloc.h"
  30
  31 bool send_meta_sptps(void *handle, uint8_t type, const char *buffer, size_t length) {
  32         connection_t *c = handle;
  33
  34         if(!c) {
  35                 logger(DEBUG_ALWAYS, LOG_ERR, "send_meta_sptps() called with NULL pointer!");
  36                 abort();
  37         }
  38
  39         buffer_add(&c->outbuf, buffer, length);
  40         io_set(&c->io, IO_READ | IO_WRITE);
  41
  42         return true;
  43 }
  44
  45 bool send_meta(connection_t *c, const char *buffer, int length) {
  46         if(!c) {
  47                 logger(DEBUG_ALWAYS, LOG_ERR, "send_meta() called with NULL pointer!");
  48                 abort();
  49         }
  50
  51         logger(DEBUG_META, LOG_DEBUG, "Sending %d bytes of metadata to %s (%s)", length,
  52                            c->name, c->hostname);
  53
  54         if(c->protocol_minor >= 2)
  55                 return sptps_send_record(&c->sptps, 0, buffer, length);
  56
  57         /* Add our data to buffer */
  58         if(c->status.encryptout) {
  59                 size_t outlen = length;
  60
  61                 if(!cipher_encrypt(c->outcipher, buffer, length, buffer_prepare(&c->outbuf, length), &outlen, false) || outlen != length) {
  62                         logger(DEBUG_ALWAYS, LOG_ERR, "Error while encrypting metadata to %s (%s)",
  63                                         c->name, c->hostname);
  64                         return false;
  65                 }
  66         } else {
  67                 buffer_add(&c->outbuf, buffer, length);
  68         }
  69
  70         io_set(&c->io, IO_READ | IO_WRITE);
  71
  72         return true;
  73 }
  74
  75 void broadcast_meta(connection_t *from, const char *buffer, int length) {
  76         for list_each(connection_t, c, connection_list)
  77                 if(c != from && c->status.active)
  78                         send_meta(c, buffer, length);
  79 }
  80
  81 bool receive_meta_sptps(void *handle, uint8_t type, const char *data, uint16_t length) {
  82         connection_t *c = handle;
  83
  84         if(!c) {
  85                 logger(DEBUG_ALWAYS, LOG_ERR, "receive_meta_sptps() called with NULL pointer!");
  86                 abort();
  87         }
  88
  89         if(type == SPTPS_HANDSHAKE) {
  90                 if(c->allow_request == ACK)
  91                         return send_ack(c);
  92                 else
  93                         return true;
  94         }
  95
  96         if(!data)
  97                 return true;
  98
  99         /* Are we receiving a TCPpacket? */
 100
 101         if(c->tcplen) {
 102                 if(length != c->tcplen)
 103                         return false;
 104                 receive_tcppacket(c, data, length);
 105                 c->tcplen = 0;
 106                 return true;
 107         }
 108
 109         /* Change newline to null byte, just like non-SPTPS requests */
 110
 111         if(data[length - 1] == '\n')
 112                 ((char *)data)[length - 1] = 0;
 113
 114         /* Otherwise we are waiting for a request */
 115
 116         return receive_request(c, data);
 117 }
 118
 119 bool receive_meta(connection_t *c) {
 120         int inlen;
 121         char inbuf[MAXBUFSIZE];
 122         char *bufp = inbuf, *endp;
 123
 124         /* Strategy:
 125            - Read as much as possible from the TCP socket in one go.
 126            - Decrypt it.
 127            - Check if a full request is in the input buffer.
 128            - If yes, process request and remove it from the buffer,
 129            then check again.
 130            - If not, keep stuff in buffer and exit.
 131          */
 132
 133         buffer_compact(&c->inbuf, MAXBUFSIZE);
 134
 135         if(sizeof inbuf <= c->inbuf.len) {
 136                 logger(DEBUG_ALWAYS, LOG_ERR, "Input buffer full for %s (%s)", c->name, c->hostname);
 137                 return false;
 138         }
 139
 140         inlen = recv(c->socket, inbuf, sizeof inbuf - c->inbuf.len, 0);
 141
 142         if(inlen <= 0) {
 143                 if(!inlen || !errno) {
 144                         logger(DEBUG_CONNECTIONS, LOG_NOTICE, "Connection closed by %s (%s)",
 145                                            c->name, c->hostname);
 146                 } else if(sockwouldblock(sockerrno))
 147                         return true;
 148                 else
 149                         logger(DEBUG_ALWAYS, LOG_ERR, "Metadata socket read error for %s (%s): %s",
 150                                    c->name, c->hostname, sockstrerror(sockerrno));
 151                 return false;
 152         }
 153
 154         do {
 155                 if(c->protocol_minor >= 2)
 156                         return sptps_receive_data(&c->sptps, bufp, inlen);
 157
 158                 if(!c->status.decryptin) {
 159                         endp = memchr(bufp, '\n', inlen);
 160                         if(endp)
 161                                 endp++;
 162                         else
 163                                 endp = bufp + inlen;
 164
 165                         buffer_add(&c->inbuf, bufp, endp - bufp);
 166
 167                         inlen -= endp - bufp;
 168                         bufp = endp;
 169                 } else {
 170                         size_t outlen = inlen;
 171
 172                         if(!cipher_decrypt(c->incipher, bufp, inlen, buffer_prepare(&c->inbuf, inlen), &outlen, false) || inlen != outlen) {
 173                                 logger(DEBUG_ALWAYS, LOG_ERR, "Error while decrypting metadata from %s (%s)",
 174                                            c->name, c->hostname);
 175                                 return false;
 176                         }
 177
 178                         inlen = 0;
 179                 }
 180
 181                 while(c->inbuf.len) {
 182                         /* Are we receiving a TCPpacket? */
 183
 184                         if(c->tcplen) {
 185                                 char *tcpbuffer = buffer_read(&c->inbuf, c->tcplen);
 186                                 if(!tcpbuffer)
 187                                         break;
 188
 189                                 if(!c->node) {
 190                                         if(c->outgoing && proxytype == PROXY_SOCKS4 && c->allow_request == ID) {
 191                                                 if(tcpbuffer[0] == 0 && tcpbuffer[1] == 0x5a) {
 192                                                         logger(DEBUG_CONNECTIONS, LOG_DEBUG, "Proxy request granted");
 193                                                 } else {
 194                                                         logger(DEBUG_CONNECTIONS, LOG_ERR, "Proxy request rejected");
 195                                                         return false;
 196                                                 }
 197                                         } else if(c->outgoing && proxytype == PROXY_SOCKS5 && c->allow_request == ID) {
 198                                                 if(tcpbuffer[0] != 5) {
 199                                                         logger(DEBUG_CONNECTIONS, LOG_ERR, "Invalid response from proxy server");
 200                                                         return false;
 201                                                 }
 202                                                 if(tcpbuffer[1] == (char)0xff) {
 203                                                         logger(DEBUG_CONNECTIONS, LOG_ERR, "Proxy request rejected: unsuitable authentication method");
 204                                                         return false;
 205                                                 }
 206                                                 if(tcpbuffer[2] != 5) {
 207                                                         logger(DEBUG_CONNECTIONS, LOG_ERR, "Invalid response from proxy server");
 208                                                         return false;
 209                                                 }
 210                                                 if(tcpbuffer[3] == 0) {
 211                                                         logger(DEBUG_CONNECTIONS, LOG_DEBUG, "Proxy request granted");
 212                                                 } else {
 213                                                         logger(DEBUG_CONNECTIONS, LOG_DEBUG, "Proxy request rejected");
 214                                                         return false;
 215                                                 }
 216                                         } else {
 217                                                 logger(DEBUG_CONNECTIONS, LOG_ERR, "c->tcplen set but c->node is NULL!");
 218                                                 abort();
 219                                         }
 220                                 } else {
 221                                         if(c->allow_request == ALL) {
 222                                                 receive_tcppacket(c, tcpbuffer, c->tcplen);
 223                                         } else {
 224                                                 logger(DEBUG_CONNECTIONS, LOG_ERR, "Got unauthorized TCP packet from %s (%s)", c->name, c->hostname);
 225                                                 return false;
 226                                         }
 227                                 }
 228
 229                                 c->tcplen = 0;
 230                         }
 231
 232                         /* Otherwise we are waiting for a request */
 233
 234                         char *request = buffer_readline(&c->inbuf);
 235                         if(request) {
 236                                 bool result = receive_request(c, request);
 237                                 if(!result)
 238                                         return false;
 239                                 continue;
 240                         } else {
 241                                 break;
 242                         }
 243                 }
 244         } while(inlen);
 245
 246         return true;
 247 }