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& tags, std::string& prefix, std::string& command, CommandBase::Params& params)
  42 {
  43         std::string token;
  44         irc::tokenstream tokens(line);
  45
  46         if (!tokens.GetMiddle(token))
  47                 return;
  48
  49         if (token[0] == '@')
  50         {
  51                 if (token.length() <= 1)
  52                 {
  53                         this->SendError("BUG: Received a message with empty tags: " + line);
  54                         return;
  55                 }
  56
  57                 tags.assign(token, 1, std::string::npos);
  58                 if (!tokens.GetMiddle(token))
  59                 {
  60                         this->SendError("BUG: Received a message with no command: " + line);
  61                         return;
  62                 }
  63         }
  64
  65         if (token[0] == ':')
  66         {
  67                 if (token.length() <= 1)
  68                 {
  69                         this->SendError("BUG: Received a message with an empty prefix: " + line);
  70                         return;
  71                 }
  72
  73                 prefix.assign(token, 1, std::string::npos);
  74                 if (!tokens.GetMiddle(token))
  75                 {
  76                         this->SendError("BUG: Received a message with no command: " + line);
  77                         return;
  78                 }
  79         }
  80
  81         command.assign(token);
  82         while (tokens.GetTrailing(token))
  83                 params.push_back(token);
  84 }
  85
  86 void TreeSocket::ProcessLine(std::string &line)
  87 {
  88         std::string tags;
  89         std::string prefix;
  90         std::string command;
  91         CommandBase::Params params;
  92
  93         ServerInstance->Logs->Log(MODNAME, LOG_RAWIO, "S[%d] I %s", this->GetFd(), line.c_str());
  94
  95         Split(line, tags, prefix, command, params);
  96
  97         if (command.empty())
  98                 return;
  99
 100         switch (this->LinkState)
 101         {
 102                 case WAIT_AUTH_1:
 103                         /*
 104                          * State WAIT_AUTH_1:
 105                          *  Waiting for SERVER command from remote server. Server initiating
 106                          *  the connection sends the first SERVER command, listening server
 107                          *  replies with theirs if its happy, then if the initiator is happy,
 108                          *  it starts to send its net sync, which starts the merge, otherwise
 109                          *  it sends an ERROR.
 110                          */
 111                         if (command == "PASS")
 112                         {
 113                                 /*
 114                                  * Ignore this silently. Some services packages insist on sending PASS, even
 115                                  * when it is not required (i.e. by us). We have to ignore this here, otherwise
 116                                  * as it's an unknown command (effectively), it will cause the connection to be
 117                                  * closed, which probably isn't what people want. -- w00t
 118                                  */
 119                         }
 120                         else if (command == "SERVER")
 121                         {
 122                                 this->Inbound_Server(params);
 123                         }
 124                         else if (command == "ERROR")
 125                         {
 126                                 this->Error(params);
 127                         }
 128                         else if (command == "USER")
 129                         {
 130                                 this->SendError("Client connections to this port are prohibited.");
 131                         }
 132                         else if (command == "CAPAB")
 133                         {
 134                                 this->Capab(params);
 135                         }
 136                         else
 137                         {
 138                                 this->SendError("Invalid command in negotiation phase: " + command);
 139                         }
 140                 break;
 141                 case WAIT_AUTH_2:
 142                         /*
 143                          * State WAIT_AUTH_2:
 144                          *  We have sent SERVER to the other side of the connection. Now we're waiting for them to start BURST.
 145                          *  The other option at this stage of things, of course, is for them to close our connection thanks
 146                          *  to invalid credentials.. -- w
 147                          */
 148                         if (command == "SERVER")
 149                         {
 150                                 /*
 151                                  * Connection is either attempting to re-auth itself (stupid) or sending netburst without sending BURST.
 152                                  * Both of these aren't allowable, so block them here. -- w
 153                                  */
 154                                 this->SendError("You may not re-authenticate or commence netburst without sending BURST.");
 155                         }
 156                         else if (command == "BURST")
 157                         {
 158                                 if (params.size())
 159                                 {
 160                                         time_t them = ConvToNum<time_t>(params[0]);
 161                                         time_t delta = them - ServerInstance->Time();
 162                                         if ((delta < -600) || (delta > 600))
 163                                         {
 164                                                 ServerInstance->SNO->WriteGlobalSno('l', "\002ERROR\002: Your clocks are off by %ld seconds (this is more than five minutes). Link aborted, \002PLEASE SYNC YOUR CLOCKS!\002", labs((long)delta));
 165                                                 SendError("Your clocks are out by "+ConvToStr(labs((long)delta))+" seconds (this is more than five minutes). Link aborted, PLEASE SYNC YOUR CLOCKS!");
 166                                                 return;
 167                                         }
 168                                         else if ((delta < -30) || (delta > 30))
 169                                         {
 170                                                 ServerInstance->SNO->WriteGlobalSno('l', "\002WARNING\002: Your clocks are off by %ld seconds. Please consider syncing your clocks.", labs((long)delta));
 171                                         }
 172                                 }
 173
 174                                 // Check for duplicate server name/sid again, it's possible that a new
 175                                 // server was introduced while we were waiting for them to send BURST.
 176                                 // (we do not reserve their server name/sid when they send SERVER, we do it now)
 177                                 if (!CheckDuplicate(capab->name, capab->sid))
 178                                         return;
 179
 180                                 FinishAuth(capab->name, capab->sid, capab->description, capab->hidden);
 181                         }
 182                         else if (command == "ERROR")
 183                         {
 184                                 this->Error(params);
 185                         }
 186                         else if (command == "CAPAB")
 187                         {
 188                                 this->Capab(params);
 189                         }
 190
 191                 break;
 192                 case CONNECTING:
 193                         /*
 194                          * State CONNECTING:
 195                          *  We're connecting (OUTGOING) to another server. They are in state WAIT_AUTH_1 until they verify
 196                          *  our credentials, when they proceed into WAIT_AUTH_2 and send SERVER to us. We then send BURST
 197                          *  + our netburst, which will put them into CONNECTED state. -- w
 198                          */
 199                         if (command == "SERVER")
 200                         {
 201                                 // Our credentials have been accepted, send netburst. (this puts US into the CONNECTED state)
 202                                 this->Outbound_Reply_Server(params);
 203                         }
 204                         else if (command == "ERROR")
 205                         {
 206                                 this->Error(params);
 207                         }
 208                         else if (command == "CAPAB")
 209                         {
 210                                 this->Capab(params);
 211                         }
 212                 break;
 213                 case CONNECTED:
 214                         /*
 215                          * State CONNECTED:
 216                          *  Credentials have been exchanged, we've gotten their 'BURST' (or sent ours).
 217                          *  Anything from here on should be accepted a little more reasonably.
 218                          */
 219                         this->ProcessConnectedLine(tags, prefix, command, params);
 220                 break;
 221                 case DYING:
 222                 break;
 223         }
 224 }
 225
 226 User* TreeSocket::FindSource(const std::string& prefix, const std::string& command)
 227 {
 228         // Empty prefix means the source is the directly connected server that sent this command
 229         if (prefix.empty())
 230                 return MyRoot->ServerUser;
 231
 232         if (prefix.size() == 3)
 233         {
 234                 // Prefix looks like a sid
 235                 TreeServer* server = Utils->FindServerID(prefix);
 236                 if (server)
 237                         return server->ServerUser;
 238         }
 239         else
 240         {
 241                 // If the prefix string is a uuid FindUUID() returns the appropriate User object
 242                 User* user = ServerInstance->FindUUID(prefix);
 243                 if (user)
 244                         return user;
 245         }
 246
 247         // Some implementations wrongly send a server name as prefix occasionally, handle that too for now
 248         TreeServer* const server = Utils->FindServer(prefix);
 249         if (server)
 250                 return server->ServerUser;
 251
 252         /* It is important that we don't close the link here, unknown prefix can occur
 253          * due to various race conditions such as the KILL message for a user somehow
 254          * crossing the users QUIT further upstream from the server. Thanks jilles!
 255          */
 256
 257         if ((prefix.length() == UIDGenerator::UUID_LENGTH) && (isdigit(prefix[0])) &&
 258                 ((command == "FMODE") || (command == "MODE") || (command == "KICK") || (command == "TOPIC") || (command == "KILL") || (command == "ADDLINE") || (command == "DELLINE")))
 259         {
 260                 /* Special case, we cannot drop these commands as they've been committed already on a
 261                  * part of the network by the time we receive them, so in this scenario pretend the
 262                  * command came from a server to avoid desync.
 263                  */
 264
 265                 TreeServer* const usersserver = Utils->FindServerID(prefix.substr(0, 3));
 266                 if (usersserver)
 267                         return usersserver->ServerUser;
 268                 return this->MyRoot->ServerUser;
 269         }
 270
 271         // Unknown prefix
 272         return NULL;
 273 }
 274
 275 void TreeSocket::ProcessTag(User* source, const std::string& tag, ClientProtocol::TagMap& tags)
 276 {
 277         std::string tagkey;
 278         std::string tagval;
 279         const std::string::size_type p = tag.find('=');
 280         if (p != std::string::npos)
 281         {
 282                 // Tag has a value
 283                 tagkey.assign(tag, 0, p);
 284                 tagval.assign(tag, p + 1, std::string::npos);
 285         }
 286         else
 287         {
 288                 tagkey.assign(tag);
 289         }
 290
 291         const Events::ModuleEventProvider::SubscriberList& list = Utils->Creator->tagevprov.GetSubscribers();
 292         for (Events::ModuleEventProvider::SubscriberList::const_iterator i = list.begin(); i != list.end(); ++i)
 293         {
 294                 ClientProtocol::MessageTagProvider* const tagprov = static_cast<ClientProtocol::MessageTagProvider*>(*i);
 295                 const ModResult res = tagprov->OnProcessTag(source, tagkey, tagval);
 296                 if (res == MOD_RES_ALLOW)
 297                         tags.insert(std::make_pair(tagkey, ClientProtocol::MessageTagData(tagprov, tagval)));
 298                 else if (res == MOD_RES_DENY)
 299                         break;
 300         }
 301 }
 302
 303 void TreeSocket::ProcessConnectedLine(std::string& taglist, std::string& prefix, std::string& command, CommandBase::Params& params)
 304 {
 305         User* who = FindSource(prefix, command);
 306         if (!who)
 307         {
 308                 ServerInstance->Logs->Log(MODNAME, LOG_DEBUG, "Command '%s' from unknown prefix '%s'! Dropping entire command.", command.c_str(), prefix.c_str());
 309                 return;
 310         }
 311
 312         /*
 313          * Check for fake direction here, and drop any instances that are found.
 314          * What is fake direction? Imagine the following server setup:
 315          *    0AA <-> 0AB <-> 0AC
 316          * Fake direction would be 0AC sending a message to 0AB claiming to be from
 317          * 0AA, or something similar. Basically, a message taking a path that *cannot*
 318          * be correct.
 319          *
 320          * When would this be seen?
 321          * Well, hopefully never. It could be caused by race conditions, bugs, or
 322          * "miscreant" servers, though, so let's check anyway. -- w
 323          *
 324          * We also check here for totally invalid prefixes (prefixes that are neither
 325          * a valid SID or a valid UUID, so that invalid UUID or SID never makes it
 326          * to the higher level functions. -- B
 327          */
 328         TreeServer* const server = TreeServer::Get(who);
 329         if (server->GetSocket() != this)
 330         {
 331                 ServerInstance->Logs->Log(MODNAME, LOG_DEBUG, "Protocol violation: Fake direction '%s' from connection '%s'", prefix.c_str(), linkID.c_str());
 332                 return;
 333         }
 334
 335         // Translate commands coming from servers using an older protocol
 336         if (proto_version < PROTO_NEWEST)
 337         {
 338                 if (!PreProcessOldProtocolMessage(who, command, params))
 339                         return;
 340         }
 341
 342         ServerCommand* scmd = Utils->Creator->CmdManager.GetHandler(command);
 343         CommandBase* cmdbase = scmd;
 344         Command* cmd = NULL;
 345         if (!scmd)
 346         {
 347                 // Not a special server-to-server command
 348                 cmd = ServerInstance->Parser.GetHandler(command);
 349                 if (!cmd)
 350                 {
 351                         if (command == "ERROR")
 352                         {
 353                                 this->Error(params);
 354                                 return;
 355                         }
 356                         else if (command == "BURST")
 357                         {
 358                                 // This is sent even when there is no need for it, drop it here for now
 359                                 return;
 360                         }
 361
 362                         throw ProtocolException("Unknown command: " + command);
 363                 }
 364                 cmdbase = cmd;
 365         }
 366
 367         if (params.size() < cmdbase->min_params)
 368                 throw ProtocolException("Insufficient parameters");
 369
 370         if ((!params.empty()) && (params.back().empty()) && (!cmdbase->allow_empty_last_param))
 371         {
 372                 // 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
 373                 if (params.size()-1 < cmdbase->min_params)
 374                         return;
 375                 params.pop_back();
 376         }
 377
 378         CmdResult res;
 379         ClientProtocol::TagMap tags;
 380         std::string tag;
 381         irc::sepstream tagstream(taglist, ';');
 382         while (tagstream.GetToken(tag))
 383                 ProcessTag(who, tag, tags);
 384
 385         CommandBase::Params newparams(params, tags);
 386
 387         if (scmd)
 388                 res = scmd->Handle(who, newparams);
 389         else
 390         {
 391                 res = cmd->Handle(who, newparams);
 392                 if (res == CMD_INVALID)
 393                         throw ProtocolException("Error in command handler");
 394         }
 395
 396         if (res == CMD_SUCCESS)
 397                 Utils->RouteCommand(server->GetRoute(), cmdbase, newparams, who);
 398 }
 399
 400 void TreeSocket::OnTimeout()
 401 {
 402         ServerInstance->SNO->WriteGlobalSno('l', "CONNECT: Connection to \002%s\002 timed out.", linkID.c_str());
 403 }
 404
 405 void TreeSocket::Close()
 406 {
 407         if (fd < 0)
 408                 return;
 409
 410         ServerInstance->GlobalCulls.AddItem(this);
 411         this->BufferedSocket::Close();
 412         SetError("Remote host closed connection");
 413
 414         // Connection closed.
 415         // If the connection is fully up (state CONNECTED)
 416         // then propogate a netsplit to all peers.
 417         if (MyRoot)
 418                 MyRoot->SQuit(getError());
 419
 420         ServerInstance->SNO->WriteGlobalSno('l', "Connection to '\002%s\002' failed.", linkID.c_str());
 421
 422         time_t server_uptime = ServerInstance->Time() - this->age;
 423         if (server_uptime)
 424         {
 425                 std::string timestr = InspIRCd::DurationString(server_uptime);
 426                 ServerInstance->SNO->WriteGlobalSno('l', "Connection to '\002%s\002' was established for %s", linkID.c_str(), timestr.c_str());
 427         }
 428 }
 429
 430 void TreeSocket::FinishAuth(const std::string& remotename, const std::string& remotesid, const std::string& remotedesc, bool hidden)
 431 {
 432         this->LinkState = CONNECTED;
 433         Utils->timeoutlist.erase(this);
 434
 435         linkID = remotename;
 436
 437         MyRoot = new TreeServer(remotename, remotedesc, remotesid, Utils->TreeRoot, this, hidden);
 438
 439         // Mark the server as bursting
 440         MyRoot->BeginBurst();
 441         this->DoBurst(MyRoot);
 442
 443         CommandServer::Builder(MyRoot).Forward(MyRoot);
 444 }