src/modules/m_spanningtree/treesocket2.cpp

   1 /*
   2  * InspIRCd -- Internet Relay Chat Daemon
   3  *
   4  *   Copyright (C) 2019 linuxdaemon <linuxdaemon.irc@gmail.com>
   5  *   Copyright (C) 2013, 2018-2020 Sadie Powell <sadie@witchery.services>
   6  *   Copyright (C) 2013 Adam <Adam@anope.org>
   7  *   Copyright (C) 2012-2016 Attila Molnar <attilamolnar@hush.com>
   8  *   Copyright (C) 2012, 2019 Robby <robby@chatbelgie.be>
   9  *   Copyright (C) 2009-2010 Daniel De Graaf <danieldg@inspircd.org>
  10  *   Copyright (C) 2008, 2012 Robin Burchell <robin+git@viroteck.net>
  11  *   Copyright (C) 2007-2008, 2010 Craig Edwards <brain@inspircd.org>
  12  *   Copyright (C) 2007 Dennis Friis <peavey@inspircd.org>
  13  *
  14  * This file is part of InspIRCd.  InspIRCd is free software: you can
  15  * redistribute it and/or modify it under the terms of the GNU General Public
  16  * License as published by the Free Software Foundation, version 2.
  17  *
  18  * This program is distributed in the hope that it will be useful, but WITHOUT
  19  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
  20  * FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more
  21  * details.
  22  *
  23  * You should have received a copy of the GNU General Public License
  24  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  25  */
  26
  27
  28 #include "inspircd.h"
  29
  30 #include "main.h"
  31 #include "utils.h"
  32 #include "treeserver.h"
  33 #include "treesocket.h"
  34 #include "resolvers.h"
  35 #include "commands.h"
  36
  37 /* Handle ERROR command */
  38 void TreeSocket::Error(CommandBase::Params& params)
  39 {
  40         std::string msg = params.size() ? params[0] : "";
  41         SetError("received ERROR " + msg);
  42 }
  43
  44 void TreeSocket::Split(const std::string& line, std::string& tags, std::string& prefix, std::string& command, CommandBase::Params& params)
  45 {
  46         std::string token;
  47         irc::tokenstream tokens(line);
  48
  49         if (!tokens.GetMiddle(token))
  50                 return;
  51
  52         if (token[0] == '@')
  53         {
  54                 if (token.length() <= 1)
  55                 {
  56                         this->SendError("BUG: Received a message with empty tags: " + line);
  57                         return;
  58                 }
  59
  60                 tags.assign(token, 1, std::string::npos);
  61                 if (!tokens.GetMiddle(token))
  62                 {
  63                         this->SendError("BUG: Received a message with no command: " + line);
  64                         return;
  65                 }
  66         }
  67
  68         if (token[0] == ':')
  69         {
  70                 if (token.length() <= 1)
  71                 {
  72                         this->SendError("BUG: Received a message with an empty prefix: " + line);
  73                         return;
  74                 }
  75
  76                 prefix.assign(token, 1, std::string::npos);
  77                 if (!tokens.GetMiddle(token))
  78                 {
  79                         this->SendError("BUG: Received a message with no command: " + line);
  80                         return;
  81                 }
  82         }
  83
  84         command.assign(token);
  85         while (tokens.GetTrailing(token))
  86                 params.push_back(token);
  87 }
  88
  89 void TreeSocket::ProcessLine(std::string &line)
  90 {
  91         std::string tags;
  92         std::string prefix;
  93         std::string command;
  94         CommandBase::Params params;
  95
  96         ServerInstance->Logs->Log(MODNAME, LOG_RAWIO, "S[%d] I %s", this->GetFd(), line.c_str());
  97
  98         Split(line, tags, prefix, command, params);
  99
 100         if (command.empty())
 101                 return;
 102
 103         switch (this->LinkState)
 104         {
 105                 case WAIT_AUTH_1:
 106                         /*
 107                          * State WAIT_AUTH_1:
 108                          *  Waiting for SERVER command from remote server. Server initiating
 109                          *  the connection sends the first SERVER command, listening server
 110                          *  replies with theirs if its happy, then if the initiator is happy,
 111                          *  it starts to send its net sync, which starts the merge, otherwise
 112                          *  it sends an ERROR.
 113                          */
 114                         if (command == "PASS")
 115                         {
 116                                 /*
 117                                  * Ignore this silently. Some services packages insist on sending PASS, even
 118                                  * when it is not required (i.e. by us). We have to ignore this here, otherwise
 119                                  * as it's an unknown command (effectively), it will cause the connection to be
 120                                  * closed, which probably isn't what people want. -- w00t
 121                                  */
 122                         }
 123                         else if (command == "SERVER")
 124                         {
 125                                 this->Inbound_Server(params);
 126                         }
 127                         else if (command == "ERROR")
 128                         {
 129                                 this->Error(params);
 130                         }
 131                         else if (command == "USER")
 132                         {
 133                                 this->SendError("Client connections to this port are prohibited.");
 134                         }
 135                         else if (command == "CAPAB")
 136                         {
 137                                 this->Capab(params);
 138                         }
 139                         else
 140                         {
 141                                 this->SendError("Invalid command in negotiation phase: " + command);
 142                         }
 143                 break;
 144                 case WAIT_AUTH_2:
 145                         /*
 146                          * State WAIT_AUTH_2:
 147                          *  We have sent SERVER to the other side of the connection. Now we're waiting for them to start BURST.
 148                          *  The other option at this stage of things, of course, is for them to close our connection thanks
 149                          *  to invalid credentials.. -- w
 150                          */
 151                         if (command == "SERVER")
 152                         {
 153                                 /*
 154                                  * Connection is either attempting to re-auth itself (stupid) or sending netburst without sending BURST.
 155                                  * Both of these aren't allowable, so block them here. -- w
 156                                  */
 157                                 this->SendError("You may not re-authenticate or commence netburst without sending BURST.");
 158                         }
 159                         else if (command == "BURST")
 160                         {
 161                                 if (!params.empty())
 162                                 {
 163                                         time_t them = ConvToNum<time_t>(params[0]);
 164                                         time_t delta = them - ServerInstance->Time();
 165                                         if ((delta < -60) || (delta > 60))
 166                                         {
 167                                                 ServerInstance->SNO->WriteGlobalSno('l', "\002ERROR\002: Your clocks are off by %ld seconds (this is more than one minute). Link aborted, \002PLEASE SYNC YOUR CLOCKS!\002", labs((long)delta));
 168                                                 SendError("Your clocks are out by "+ConvToStr(labs((long)delta))+" seconds (this is more than one minute). Link aborted, PLEASE SYNC YOUR CLOCKS!");
 169                                                 return;
 170                                         }
 171                                         else if ((delta < -15) || (delta > 15))
 172                                         {
 173                                                 ServerInstance->SNO->WriteGlobalSno('l', "\002WARNING\002: Your clocks are off by %ld seconds. Please consider syncing your clocks.", labs((long)delta));
 174                                         }
 175                                 }
 176
 177                                 // Check for duplicate server name/sid again, it's possible that a new
 178                                 // server was introduced while we were waiting for them to send BURST.
 179                                 // (we do not reserve their server name/sid when they send SERVER, we do it now)
 180                                 if (!CheckDuplicate(capab->name, capab->sid))
 181                                         return;
 182
 183                                 FinishAuth(capab->name, capab->sid, capab->description, capab->hidden);
 184                         }
 185                         else if (command == "ERROR")
 186                         {
 187                                 this->Error(params);
 188                         }
 189                         else if (command == "CAPAB")
 190                         {
 191                                 this->Capab(params);
 192                         }
 193
 194                 break;
 195                 case CONNECTING:
 196                         /*
 197                          * State CONNECTING:
 198                          *  We're connecting (OUTGOING) to another server. They are in state WAIT_AUTH_1 until they verify
 199                          *  our credentials, when they proceed into WAIT_AUTH_2 and send SERVER to us. We then send BURST
 200                          *  + our netburst, which will put them into CONNECTED state. -- w
 201                          */
 202                         if (command == "SERVER")
 203                         {
 204                                 // Our credentials have been accepted, send netburst. (this puts US into the CONNECTED state)
 205                                 this->Outbound_Reply_Server(params);
 206                         }
 207                         else if (command == "ERROR")
 208                         {
 209                                 this->Error(params);
 210                         }
 211                         else if (command == "CAPAB")
 212                         {
 213                                 this->Capab(params);
 214                         }
 215                 break;
 216                 case CONNECTED:
 217                         /*
 218                          * State CONNECTED:
 219                          *  Credentials have been exchanged, we've gotten their 'BURST' (or sent ours).
 220                          *  Anything from here on should be accepted a little more reasonably.
 221                          */
 222                         this->ProcessConnectedLine(tags, prefix, command, params);
 223                 break;
 224                 case DYING:
 225                 break;
 226         }
 227 }
 228
 229 User* TreeSocket::FindSource(const std::string& prefix, const std::string& command)
 230 {
 231         // Empty prefix means the source is the directly connected server that sent this command
 232         if (prefix.empty())
 233                 return MyRoot->ServerUser;
 234
 235         if (prefix.size() == 3)
 236         {
 237                 // Prefix looks like a sid
 238                 TreeServer* server = Utils->FindServerID(prefix);
 239                 if (server)
 240                         return server->ServerUser;
 241         }
 242         else
 243         {
 244                 // If the prefix string is a uuid FindUUID() returns the appropriate User object
 245                 User* user = ServerInstance->FindUUID(prefix);
 246                 if (user)
 247                         return user;
 248         }
 249
 250         // Some implementations wrongly send a server name as prefix occasionally, handle that too for now
 251         TreeServer* const server = Utils->FindServer(prefix);
 252         if (server)
 253                 return server->ServerUser;
 254
 255         /* It is important that we don't close the link here, unknown prefix can occur
 256          * due to various race conditions such as the KILL message for a user somehow
 257          * crossing the users QUIT further upstream from the server. Thanks jilles!
 258          */
 259
 260         if ((prefix.length() == UIDGenerator::UUID_LENGTH) && (isdigit(prefix[0])) &&
 261                 ((command == "FMODE") || (command == "MODE") || (command == "KICK") || (command == "TOPIC") || (command == "KILL") || (command == "ADDLINE") || (command == "DELLINE")))
 262         {
 263                 /* Special case, we cannot drop these commands as they've been committed already on a
 264                  * part of the network by the time we receive them, so in this scenario pretend the
 265                  * command came from a server to avoid desync.
 266                  */
 267
 268                 TreeServer* const usersserver = Utils->FindServerID(prefix.substr(0, 3));
 269                 if (usersserver)
 270                         return usersserver->ServerUser;
 271                 return this->MyRoot->ServerUser;
 272         }
 273
 274         // Unknown prefix
 275         return NULL;
 276 }
 277
 278 void TreeSocket::ProcessTag(User* source, const std::string& tag, ClientProtocol::TagMap& tags)
 279 {
 280         std::string tagkey;
 281         std::string tagval;
 282         const std::string::size_type p = tag.find('=');
 283         if (p != std::string::npos)
 284         {
 285                 // Tag has a value
 286                 tagkey.assign(tag, 0, p);
 287                 tagval.assign(tag, p + 1, std::string::npos);
 288         }
 289         else
 290         {
 291                 tagkey.assign(tag);
 292         }
 293
 294         const Events::ModuleEventProvider::SubscriberList& list = Utils->Creator->tagevprov.GetSubscribers();
 295         for (Events::ModuleEventProvider::SubscriberList::const_iterator i = list.begin(); i != list.end(); ++i)
 296         {
 297                 ClientProtocol::MessageTagProvider* const tagprov = static_cast<ClientProtocol::MessageTagProvider*>(*i);
 298                 const ModResult res = tagprov->OnProcessTag(source, tagkey, tagval);
 299                 if (res == MOD_RES_ALLOW)
 300                         tags.insert(std::make_pair(tagkey, ClientProtocol::MessageTagData(tagprov, tagval)));
 301                 else if (res == MOD_RES_DENY)
 302                         break;
 303         }
 304 }
 305
 306 void TreeSocket::ProcessConnectedLine(std::string& taglist, std::string& prefix, std::string& command, CommandBase::Params& params)
 307 {
 308         User* who = FindSource(prefix, command);
 309         if (!who)
 310         {
 311                 ServerInstance->Logs->Log(MODNAME, LOG_DEBUG, "Command '%s' from unknown prefix '%s'! Dropping entire command.", command.c_str(), prefix.c_str());
 312                 return;
 313         }
 314
 315         /*
 316          * Check for fake direction here, and drop any instances that are found.
 317          * What is fake direction? Imagine the following server setup:
 318          *    0AA <-> 0AB <-> 0AC
 319          * Fake direction would be 0AC sending a message to 0AB claiming to be from
 320          * 0AA, or something similar. Basically, a message taking a path that *cannot*
 321          * be correct.
 322          *
 323          * When would this be seen?
 324          * Well, hopefully never. It could be caused by race conditions, bugs, or
 325          * "miscreant" servers, though, so let's check anyway. -- w
 326          *
 327          * We also check here for totally invalid prefixes (prefixes that are neither
 328          * a valid SID or a valid UUID, so that invalid UUID or SID never makes it
 329          * to the higher level functions. -- B
 330          */
 331         TreeServer* const server = TreeServer::Get(who);
 332         if (server->GetSocket() != this)
 333         {
 334                 ServerInstance->Logs->Log(MODNAME, LOG_DEBUG, "Protocol violation: Fake direction '%s' from connection '%s'", prefix.c_str(), linkID.c_str());
 335                 return;
 336         }
 337
 338         // Translate commands coming from servers using an older protocol
 339         if (proto_version < PROTO_NEWEST)
 340         {
 341                 if (!PreProcessOldProtocolMessage(who, command, params))
 342                         return;
 343         }
 344
 345         ServerCommand* scmd = Utils->Creator->CmdManager.GetHandler(command);
 346         CommandBase* cmdbase = scmd;
 347         Command* cmd = NULL;
 348         if (!scmd)
 349         {
 350                 // Not a special server-to-server command
 351                 cmd = ServerInstance->Parser.GetHandler(command);
 352                 if (!cmd)
 353                 {
 354                         if (command == "ERROR")
 355                         {
 356                                 this->Error(params);
 357                                 return;
 358                         }
 359                         else if (command == "BURST")
 360                         {
 361                                 // This is sent even when there is no need for it, drop it here for now
 362                                 return;
 363                         }
 364
 365                         throw ProtocolException("Unknown command: " + command);
 366                 }
 367                 cmdbase = cmd;
 368         }
 369
 370         if (params.size() < cmdbase->min_params)
 371                 throw ProtocolException("Insufficient parameters");
 372
 373         if ((!params.empty()) && (params.back().empty()) && (!cmdbase->allow_empty_last_param))
 374         {
 375                 // 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
 376                 if (params.size()-1 < cmdbase->min_params)
 377                         return;
 378                 params.pop_back();
 379         }
 380
 381         CmdResult res;
 382         ClientProtocol::TagMap tags;
 383         std::string tag;
 384         irc::sepstream tagstream(taglist, ';');
 385         while (tagstream.GetToken(tag))
 386                 ProcessTag(who, tag, tags);
 387
 388         CommandBase::Params newparams(params, tags);
 389
 390         if (scmd)
 391                 res = scmd->Handle(who, newparams);
 392         else
 393         {
 394                 res = cmd->Handle(who, newparams);
 395                 if (res == CMD_INVALID)
 396                         throw ProtocolException("Error in command handler");
 397         }
 398
 399         if (res == CMD_SUCCESS)
 400                 Utils->RouteCommand(server->GetRoute(), cmdbase, newparams, who);
 401 }
 402
 403 void TreeSocket::OnTimeout()
 404 {
 405         ServerInstance->SNO->WriteGlobalSno('l', "CONNECT: Connection to \002%s\002 timed out.", linkID.c_str());
 406 }
 407
 408 void TreeSocket::Close()
 409 {
 410         if (!HasFd())
 411                 return;
 412
 413         ServerInstance->GlobalCulls.AddItem(this);
 414         this->BufferedSocket::Close();
 415         SetError("Remote host closed connection");
 416
 417         // Connection closed.
 418         // If the connection is fully up (state CONNECTED)
 419         // then propagate a netsplit to all peers.
 420         if (MyRoot)
 421                 MyRoot->SQuit(getError(), true);
 422
 423         ServerInstance->SNO->WriteGlobalSno('l', "Connection to '\002%s\002' failed.", linkID.c_str());
 424
 425         time_t server_uptime = ServerInstance->Time() - this->age;
 426         if (server_uptime)
 427         {
 428                 std::string timestr = InspIRCd::DurationString(server_uptime);
 429                 ServerInstance->SNO->WriteGlobalSno('l', "Connection to '\002%s\002' was established for %s", linkID.c_str(), timestr.c_str());
 430         }
 431 }
 432
 433 void TreeSocket::FinishAuth(const std::string& remotename, const std::string& remotesid, const std::string& remotedesc, bool hidden)
 434 {
 435         this->LinkState = CONNECTED;
 436         Utils->timeoutlist.erase(this);
 437
 438         linkID = remotename;
 439
 440         MyRoot = new TreeServer(remotename, remotedesc, remotesid, Utils->TreeRoot, this, hidden);
 441
 442         // Mark the server as bursting
 443         MyRoot->BeginBurst();
 444         this->DoBurst(MyRoot);
 445
 446         CommandServer::Builder(MyRoot).Forward(MyRoot);
 447 }