src/modules/m_spanningtree/treesocket2.cpp

   1 /*
   2  * InspIRCd -- Internet Relay Chat Daemon
   3  *
   4  *   Copyright (C) 2007-2008, 2012 Robin Burchell <robin+git@viroteck.net>
   5  *   Copyright (C) 2009-2010 Daniel De Graaf <danieldg@inspircd.org>
   6  *   Copyright (C) 2007-2008 Craig Edwards <craigedwards@brainbox.cc>
   7  *   Copyright (C) 2008 Pippijn van Steenhoven <pip88nl@gmail.com>
   8  *   Copyright (C) 2008 Thomas Stagner <aquanight@inspircd.org>
   9  *   Copyright (C) 2007 Dennis Friis <peavey@inspircd.org>
  10  *
  11  * This file is part of InspIRCd.  InspIRCd is free software: you can
  12  * redistribute it and/or modify it under the terms of the GNU General Public
  13  * License as published by the Free Software Foundation, version 2.
  14  *
  15  * This program is distributed in the hope that it will be useful, but WITHOUT
  16  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
  17  * FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more
  18  * details.
  19  *
  20  * You should have received a copy of the GNU General Public License
  21  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  22  */
  23
  24
  25 #include "inspircd.h"
  26
  27 #include "main.h"
  28 #include "utils.h"
  29 #include "treeserver.h"
  30 #include "treesocket.h"
  31 #include "resolvers.h"
  32 #include "commands.h"
  33
  34 /* Handle ERROR command */
  35 void TreeSocket::Error(CommandBase::Params& params)
  36 {
  37         std::string msg = params.size() ? params[0] : "";
  38         SetError("received ERROR " + msg);
  39 }
  40
  41 void TreeSocket::Split(const std::string& line, std::string& prefix, std::string& command, CommandBase::Params& params)
  42 {
  43         irc::tokenstream tokens(line);
  44
  45         if (!tokens.GetMiddle(prefix))
  46                 return;
  47
  48         if (prefix[0] == ':')
  49         {
  50                 prefix.erase(prefix.begin());
  51
  52                 if (prefix.empty())
  53                 {
  54                         this->SendError("BUG (?) Empty prefix received: " + line);
  55                         return;
  56                 }
  57                 if (!tokens.GetMiddle(command))
  58                 {
  59                         this->SendError("BUG (?) Empty command received: " + line);
  60                         return;
  61                 }
  62         }
  63         else
  64         {
  65                 command = prefix;
  66                 prefix.clear();
  67         }
  68         if (command.empty())
  69                 this->SendError("BUG (?) Empty command received: " + line);
  70
  71         std::string param;
  72         while (tokens.GetTrailing(param))
  73         {
  74                 params.push_back(param);
  75         }
  76 }
  77
  78 void TreeSocket::ProcessLine(std::string &line)
  79 {
  80         std::string prefix;
  81         std::string command;
  82         CommandBase::Params params;
  83
  84         ServerInstance->Logs->Log(MODNAME, LOG_RAWIO, "S[%d] I %s", this->GetFd(), line.c_str());
  85
  86         Split(line, prefix, command, params);
  87
  88         if (command.empty())
  89                 return;
  90
  91         switch (this->LinkState)
  92         {
  93                 case WAIT_AUTH_1:
  94                         /*
  95                          * State WAIT_AUTH_1:
  96                          *  Waiting for SERVER command from remote server. Server initiating
  97                          *  the connection sends the first SERVER command, listening server
  98                          *  replies with theirs if its happy, then if the initiator is happy,
  99                          *  it starts to send its net sync, which starts the merge, otherwise
 100                          *  it sends an ERROR.
 101                          */
 102                         if (command == "PASS")
 103                         {
 104                                 /*
 105                                  * Ignore this silently. Some services packages insist on sending PASS, even
 106                                  * when it is not required (i.e. by us). We have to ignore this here, otherwise
 107                                  * as it's an unknown command (effectively), it will cause the connection to be
 108                                  * closed, which probably isn't what people want. -- w00t
 109                                  */
 110                         }
 111                         else if (command == "SERVER")
 112                         {
 113                                 this->Inbound_Server(params);
 114                         }
 115                         else if (command == "ERROR")
 116                         {
 117                                 this->Error(params);
 118                         }
 119                         else if (command == "USER")
 120                         {
 121                                 this->SendError("Client connections to this port are prohibited.");
 122                         }
 123                         else if (command == "CAPAB")
 124                         {
 125                                 this->Capab(params);
 126                         }
 127                         else
 128                         {
 129                                 this->SendError("Invalid command in negotiation phase: " + command);
 130                         }
 131                 break;
 132                 case WAIT_AUTH_2:
 133                         /*
 134                          * State WAIT_AUTH_2:
 135                          *  We have sent SERVER to the other side of the connection. Now we're waiting for them to start BURST.
 136                          *  The other option at this stage of things, of course, is for them to close our connection thanks
 137                          *  to invalid credentials.. -- w
 138                          */
 139                         if (command == "SERVER")
 140                         {
 141                                 /*
 142                                  * Connection is either attempting to re-auth itself (stupid) or sending netburst without sending BURST.
 143                                  * Both of these aren't allowable, so block them here. -- w
 144                                  */
 145                                 this->SendError("You may not re-authenticate or commence netburst without sending BURST.");
 146                         }
 147                         else if (command == "BURST")
 148                         {
 149                                 if (params.size())
 150                                 {
 151                                         time_t them = ConvToInt(params[0]);
 152                                         time_t delta = them - ServerInstance->Time();
 153                                         if ((delta < -600) || (delta > 600))
 154                                         {
 155                                                 ServerInstance->SNO->WriteGlobalSno('l',"\2ERROR\2: Your clocks are out by %ld seconds (this is more than five minutes). Link aborted, \2PLEASE SYNC YOUR CLOCKS!\2",labs((long)delta));
 156                                                 SendError("Your clocks are out by "+ConvToStr(labs((long)delta))+" seconds (this is more than five minutes). Link aborted, PLEASE SYNC YOUR CLOCKS!");
 157                                                 return;
 158                                         }
 159                                         else if ((delta < -30) || (delta > 30))
 160                                         {
 161                                                 ServerInstance->SNO->WriteGlobalSno('l',"\2WARNING\2: Your clocks are out by %ld seconds. Please consider synching your clocks.", labs((long)delta));
 162                                         }
 163                                 }
 164
 165                                 // Check for duplicate server name/sid again, it's possible that a new
 166                                 // server was introduced while we were waiting for them to send BURST.
 167                                 // (we do not reserve their server name/sid when they send SERVER, we do it now)
 168                                 if (!CheckDuplicate(capab->name, capab->sid))
 169                                         return;
 170
 171                                 FinishAuth(capab->name, capab->sid, capab->description, capab->hidden);
 172                         }
 173                         else if (command == "ERROR")
 174                         {
 175                                 this->Error(params);
 176                         }
 177                         else if (command == "CAPAB")
 178                         {
 179                                 this->Capab(params);
 180                         }
 181
 182                 break;
 183                 case CONNECTING:
 184                         /*
 185                          * State CONNECTING:
 186                          *  We're connecting (OUTGOING) to another server. They are in state WAIT_AUTH_1 until they verify
 187                          *  our credentials, when they proceed into WAIT_AUTH_2 and send SERVER to us. We then send BURST
 188                          *  + our netburst, which will put them into CONNECTED state. -- w
 189                          */
 190                         if (command == "SERVER")
 191                         {
 192                                 // Our credentials have been accepted, send netburst. (this puts US into the CONNECTED state)
 193                                 this->Outbound_Reply_Server(params);
 194                         }
 195                         else if (command == "ERROR")
 196                         {
 197                                 this->Error(params);
 198                         }
 199                         else if (command == "CAPAB")
 200                         {
 201                                 this->Capab(params);
 202                         }
 203                 break;
 204                 case CONNECTED:
 205                         /*
 206                          * State CONNECTED:
 207                          *  Credentials have been exchanged, we've gotten their 'BURST' (or sent ours).
 208                          *  Anything from here on should be accepted a little more reasonably.
 209                          */
 210                         this->ProcessConnectedLine(prefix, command, params);
 211                 break;
 212                 case DYING:
 213                 break;
 214         }
 215 }
 216
 217 User* TreeSocket::FindSource(const std::string& prefix, const std::string& command)
 218 {
 219         // Empty prefix means the source is the directly connected server that sent this command
 220         if (prefix.empty())
 221                 return MyRoot->ServerUser;
 222
 223         if (prefix.size() == 3)
 224         {
 225                 // Prefix looks like a sid
 226                 TreeServer* server = Utils->FindServerID(prefix);
 227                 if (server)
 228                         return server->ServerUser;
 229         }
 230         else
 231         {
 232                 // If the prefix string is a uuid FindUUID() returns the appropriate User object
 233                 User* user = ServerInstance->FindUUID(prefix);
 234                 if (user)
 235                         return user;
 236         }
 237
 238         // Some implementations wrongly send a server name as prefix occasionally, handle that too for now
 239         TreeServer* const server = Utils->FindServer(prefix);
 240         if (server)
 241                 return server->ServerUser;
 242
 243         /* It is important that we don't close the link here, unknown prefix can occur
 244          * due to various race conditions such as the KILL message for a user somehow
 245          * crossing the users QUIT further upstream from the server. Thanks jilles!
 246          */
 247
 248         if ((prefix.length() == UIDGenerator::UUID_LENGTH) && (isdigit(prefix[0])) &&
 249                 ((command == "FMODE") || (command == "MODE") || (command == "KICK") || (command == "TOPIC") || (command == "KILL") || (command == "ADDLINE") || (command == "DELLINE")))
 250         {
 251                 /* Special case, we cannot drop these commands as they've been committed already on a
 252                  * part of the network by the time we receive them, so in this scenario pretend the
 253                  * command came from a server to avoid desync.
 254                  */
 255
 256                 TreeServer* const usersserver = Utils->FindServerID(prefix.substr(0, 3));
 257                 if (usersserver)
 258                         return usersserver->ServerUser;
 259                 return this->MyRoot->ServerUser;
 260         }
 261
 262         // Unknown prefix
 263         return NULL;
 264 }
 265
 266 void TreeSocket::ProcessConnectedLine(std::string& prefix, std::string& command, CommandBase::Params& params)
 267 {
 268         User* who = FindSource(prefix, command);
 269         if (!who)
 270         {
 271                 ServerInstance->Logs->Log(MODNAME, LOG_DEBUG, "Command '%s' from unknown prefix '%s'! Dropping entire command.", command.c_str(), prefix.c_str());
 272                 return;
 273         }
 274
 275         /*
 276          * Check for fake direction here, and drop any instances that are found.
 277          * What is fake direction? Imagine the following server setup:
 278          *    0AA <-> 0AB <-> 0AC
 279          * Fake direction would be 0AC sending a message to 0AB claiming to be from
 280          * 0AA, or something similar. Basically, a message taking a path that *cannot*
 281          * be correct.
 282          *
 283          * When would this be seen?
 284          * Well, hopefully never. It could be caused by race conditions, bugs, or
 285          * "miscreant" servers, though, so let's check anyway. -- w
 286          *
 287          * We also check here for totally invalid prefixes (prefixes that are neither
 288          * a valid SID or a valid UUID, so that invalid UUID or SID never makes it
 289          * to the higher level functions. -- B
 290          */
 291         TreeServer* const server = TreeServer::Get(who);
 292         if (server->GetSocket() != this)
 293         {
 294                 ServerInstance->Logs->Log(MODNAME, LOG_DEBUG, "Protocol violation: Fake direction '%s' from connection '%s'", prefix.c_str(), linkID.c_str());
 295                 return;
 296         }
 297
 298         // Translate commands coming from servers using an older protocol
 299         if (proto_version < ProtocolVersion)
 300         {
 301                 if (!PreProcessOldProtocolMessage(who, command, params))
 302                         return;
 303         }
 304
 305         ServerCommand* scmd = Utils->Creator->CmdManager.GetHandler(command);
 306         CommandBase* cmdbase = scmd;
 307         Command* cmd = NULL;
 308         if (!scmd)
 309         {
 310                 // Not a special server-to-server command
 311                 cmd = ServerInstance->Parser.GetHandler(command);
 312                 if (!cmd)
 313                 {
 314                         if (command == "ERROR")
 315                         {
 316                                 this->Error(params);
 317                                 return;
 318                         }
 319                         else if (command == "BURST")
 320                         {
 321                                 // This is sent even when there is no need for it, drop it here for now
 322                                 return;
 323                         }
 324
 325                         throw ProtocolException("Unknown command");
 326                 }
 327                 cmdbase = cmd;
 328         }
 329
 330         if (params.size() < cmdbase->min_params)
 331                 throw ProtocolException("Insufficient parameters");
 332
 333         if ((!params.empty()) && (params.back().empty()) && (!cmdbase->allow_empty_last_param))
 334         {
 335                 // the last param is empty and the command handler doesn't allow that, check if there will be enough params if we drop the last
 336                 if (params.size()-1 < cmdbase->min_params)
 337                         return;
 338                 params.pop_back();
 339         }
 340
 341         CmdResult res;
 342         if (scmd)
 343                 res = scmd->Handle(who, params);
 344         else
 345         {
 346                 res = cmd->Handle(who, params);
 347                 if (res == CMD_INVALID)
 348                         throw ProtocolException("Error in command handler");
 349         }
 350
 351         if (res == CMD_SUCCESS)
 352                 Utils->RouteCommand(server->GetRoute(), cmdbase, params, who);
 353 }
 354
 355 void TreeSocket::OnTimeout()
 356 {
 357         ServerInstance->SNO->WriteGlobalSno('l', "CONNECT: Connection to \002%s\002 timed out.", linkID.c_str());
 358 }
 359
 360 void TreeSocket::Close()
 361 {
 362         if (fd < 0)
 363                 return;
 364
 365         ServerInstance->GlobalCulls.AddItem(this);
 366         this->BufferedSocket::Close();
 367         SetError("Remote host closed connection");
 368
 369         // Connection closed.
 370         // If the connection is fully up (state CONNECTED)
 371         // then propogate a netsplit to all peers.
 372         if (MyRoot)
 373                 MyRoot->SQuit(getError());
 374
 375         ServerInstance->SNO->WriteGlobalSno('l', "Connection to '\2%s\2' failed.",linkID.c_str());
 376
 377         time_t server_uptime = ServerInstance->Time() - this->age;
 378         if (server_uptime)
 379         {
 380                 std::string timestr = ModuleSpanningTree::TimeToStr(server_uptime);
 381                 ServerInstance->SNO->WriteGlobalSno('l', "Connection to '\2%s\2' was established for %s", linkID.c_str(), timestr.c_str());
 382         }
 383 }
 384
 385 void TreeSocket::FinishAuth(const std::string& remotename, const std::string& remotesid, const std::string& remotedesc, bool hidden)
 386 {
 387         this->LinkState = CONNECTED;
 388         Utils->timeoutlist.erase(this);
 389
 390         linkID = remotename;
 391
 392         MyRoot = new TreeServer(remotename, remotedesc, remotesid, Utils->TreeRoot, this, hidden);
 393
 394         // Mark the server as bursting
 395         MyRoot->BeginBurst();
 396         this->DoBurst(MyRoot);
 397
 398         CommandServer::Builder(MyRoot).Forward(MyRoot);
 399 }