/*
* InspIRCd -- Internet Relay Chat Daemon
*
* Copyright (C) 2019 linuxdaemon <linuxdaemon.irc@gmail.com>
* Copyright (C) 2018-2024 Sadie Powell <sadie@witchery.services>
* Copyright (C) 2012-2016, 2018 Attila Molnar <attilamolnar@hush.com>
* Copyright (C) 2012 Robby <robby@chatbelgie.be>
* Copyright (C) 2009-2010 Daniel De Graaf <danieldg@inspircd.org>
* Copyright (C) 2008, 2012 Robin Burchell <robin+git@viroteck.net>
* Copyright (C) 2007-2008 Dennis Friis <peavey@inspircd.org>
* Copyright (C) 2007-2008 Craig Edwards <brain@inspircd.org>
*
* This file is part of InspIRCd. InspIRCd is free software: you can
* redistribute it and/or modify it under the terms of the GNU General Public
* License as published by the Free Software Foundation, version 2.
*
* This program is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
* FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
* details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include "inspircd.h"
#include "timeutils.h"
#include "main.h"
#include "utils.h"
#include "treeserver.h"
#include "treesocket.h"
#include "resolvers.h"
#include "commands.h"
/* Handle ERROR command */
void TreeSocket::Error(CommandBase::Params& params)
{
const std::string msg = params.empty() ? "" : params[0];
SetError("received ERROR " + msg);
}
void TreeSocket::Split(const std::string& line, std::string& tags, std::string& prefix, std::string& command, CommandBase::Params& params)
{
std::string token;
irc::tokenstream tokens(line);
if (!tokens.GetMiddle(token))
return;
if (token[0] == '@')
{
if (token.length() <= 1)
{
this->SendError("BUG: Received a message with empty tags: " + line);
return;
}
tags.assign(token, 1, std::string::npos);
if (!tokens.GetMiddle(token))
{
this->SendError("BUG: Received a message with no command: " + line);
return;
}
}
if (token[0] == ':')
{
if (token.length() <= 1)
{
this->SendError("BUG: Received a message with an empty prefix: " + line);
return;
}
prefix.assign(token, 1, std::string::npos);
if (!tokens.GetMiddle(token))
{
this->SendError("BUG: Received a message with no command: " + line);
return;
}
}
command.assign(token);
while (tokens.GetTrailing(token))
params.push_back(token);
}
void TreeSocket::ProcessLine(std::string& line)
{
std::string tags;
std::string prefix;
std::string command;
CommandBase::Params params;
ServerInstance->Logs.RawIO(MODNAME, "S[{}] I {}", GetFd(), line);
Split(line, tags, prefix, command, params);
if (command.empty())
return;
switch (this->LinkState)
{
case WAIT_AUTH_1:
/*
* State WAIT_AUTH_1:
* Waiting for SERVER command from remote server. Server initiating
* the connection sends the first SERVER command, listening server
* replies with theirs if its happy, then if the initiator is happy,
* it starts to send its net sync, which starts the merge, otherwise
* it sends an ERROR.
*/
if (command == "PASS")
{
/*
* Ignore this silently. Some services packages insist on sending PASS, even
* when it is not required (i.e. by us). We have to ignore this here, otherwise
* as it's an unknown command (effectively), it will cause the connection to be
* closed, which probably isn't what people want. -- w00t
*/
}
else if (command == "SERVER")
{
this->Inbound_Server(params);
}
else if (command == "ERROR")
{
this->Error(params);
}
else if (command == "USER")
{
this->SendError("Client connections to this port are prohibited.");
}
else if (command == "CAPAB")
{
this->Capab(params);
}
else
{
this->SendError("Invalid command in negotiation phase: " + command);
}
break;
case WAIT_AUTH_2:
/*
* State WAIT_AUTH_2:
* We have sent SERVER to the other side of the connection. Now we're waiting for them to start BURST.
* The other option at this stage of things, of course, is for them to close our connection thanks
* to invalid credentials.. -- w
*/
if (command == "SERVER")
{
/*
* Connection is either attempting to re-auth itself (stupid) or sending netburst without sending BURST.
* Both of these aren't allowable, so block them here. -- w
*/
this->SendError("You may not re-authenticate or commence netburst without sending BURST.");
}
else if (command == "BURST")
{
if (!params.empty())
{
time_t them = ServerCommand::ExtractTS(params[0]);
time_t delta = them - ServerInstance->Time();
if ((delta < -15) || (delta > 15))
{
ServerInstance->SNO.WriteGlobalSno('l', "\002ERROR\002: Your clocks are off by {} seconds (this is more than fifteen seconds). Link aborted, \002PLEASE SYNC YOUR CLOCKS!\002", labs((long)delta));
SendError("Your clocks are out by "+ConvToStr(labs((long)delta))+" seconds (this is more than fifteen seconds). Link aborted, PLEASE SYNC YOUR CLOCKS!");
return;
}
else if ((delta < -5) || (delta > 5))
{
ServerInstance->SNO.WriteGlobalSno('l', "\002WARNING\002: Your clocks are off by {} seconds. Please consider syncing your clocks.", labs((long)delta));
}
}
// Check for duplicate server name/sid again, it's possible that a new
// server was introduced while we were waiting for them to send BURST.
// (we do not reserve their server name/sid when they send SERVER, we do it now)
if (!CheckDuplicate(capab->name, capab->sid))
return;
FinishAuth(capab->name, capab->sid, capab->description, capab->hidden);
}
else if (command == "ERROR")
{
this->Error(params);
}
else if (command == "CAPAB")
{
this->Capab(params);
}
else
{
ServerInstance->Logs.Debug(MODNAME, "Unknown command from fd {} in the WAIT_AUTH_2 phase: {}",
GetFd(), command);
}
break;
case CONNECTING:
/*
* State CONNECTING:
* We're connecting (OUTGOING) to another server. They are in state WAIT_AUTH_1 until they verify
* our credentials, when they proceed into WAIT_AUTH_2 and send SERVER to us. We then send BURST
* + our netburst, which will put them into CONNECTED state. -- w
*/
if (command == "SERVER")
{
// Our credentials have been accepted, send netburst. (this puts US into the CONNECTED state)
this->Outbound_Reply_Server(params);
}
else if (command == "ERROR")
{
this->Error(params);
}
else if (command == "CAPAB")
{
this->Capab(params);
}
else
{
ServerInstance->Logs.Debug(MODNAME, "Unknown command from fd {} in the CONNECTING phase: {}",
GetFd(), command);
}
break;
case CONNECTED:
/*
* State CONNECTED:
* Credentials have been exchanged, we've gotten their 'BURST' (or sent ours).
* Anything from here on should be accepted a little more reasonably.
*/
this->ProcessConnectedLine(tags, prefix, command, params);
break;
case DYING:
break;
}
}
User* TreeSocket::FindSource(const std::string& prefix, const std::string& command)
{
// Empty prefix means the source is the directly connected server that sent this command
if (prefix.empty())
return MyRoot->ServerUser;
if (prefix.size() == 3)
{
// Prefix looks like a sid
TreeServer* server = Utils->FindServerID(prefix);
if (server)
return server->ServerUser;
}
else
{
// If the prefix string is a uuid FindUUID() returns the appropriate User object
auto* user = ServerInstance->Users.FindUUID(prefix);
if (user)
return user;
}
// Some implementations wrongly send a server name as prefix occasionally, handle that too for now
TreeServer* const server = Utils->FindServer(prefix);
if (server)
return server->ServerUser;
/* It is important that we don't close the link here, unknown prefix can occur
* due to various race conditions such as the KILL message for a user somehow
* crossing the users QUIT further upstream from the server. Thanks jilles!
*/
if ((prefix.length() == UIDGenerator::UUID_LENGTH) && (isdigit(prefix[0])) &&
((command == "FMODE") || (command == "MODE") || (command == "KICK") || (command == "TOPIC") || (command == "KILL") || (command == "ADDLINE") || (command == "DELLINE")))
{
/* Special case, we cannot drop these commands as they've been committed already on a
* part of the network by the time we receive them, so in this scenario pretend the
* command came from a server to avoid desync.
*/
TreeServer* const usersserver = Utils->FindServerID(prefix.substr(0, 3));
if (usersserver)
return usersserver->ServerUser;
return this->MyRoot->ServerUser;
}
// Unknown prefix
return nullptr;
}
void TreeSocket::ProcessTag(User* source, const std::string& tag, ClientProtocol::TagMap& tags)
{
std::string tagkey;
std::string tagval;
const std::string::size_type p = tag.find('=');
if (p != std::string::npos)
{
// Tag has a value
tagkey.assign(tag, 0, p);
tagval.assign(tag, p + 1, std::string::npos);
}
else
{
tagkey.assign(tag);
}
for (auto* subscriber : Utils->Creator->tagevprov.GetSubscribers())
{
ClientProtocol::MessageTagProvider* const tagprov = static_cast<ClientProtocol::MessageTagProvider*>(subscriber);
const ModResult res = tagprov->OnProcessTag(source, tagkey, tagval);
if (res == MOD_RES_ALLOW)
tags.emplace(tagkey, ClientProtocol::MessageTagData(tagprov, tagval));
else if (res == MOD_RES_DENY)
break;
}
}
void TreeSocket::ProcessConnectedLine(std::string& taglist, std::string& prefix, std::string& command, CommandBase::Params& params)
{
User* who = FindSource(prefix, command);
if (!who)
{
ServerInstance->Logs.Debug(MODNAME, "Command '{}' from unknown prefix '{}'! Dropping entire command.", command, prefix);
return;
}
/*
* Check for fake direction here, and drop any instances that are found.
* What is fake direction? Imagine the following server setup:
* 0AA <-> 0AB <-> 0AC
* Fake direction would be 0AC sending a message to 0AB claiming to be from
* 0AA, or something similar. Basically, a message taking a path that *cannot*
* be correct.
*
* When would this be seen?
* Well, hopefully never. It could be caused by race conditions, bugs, or
* "miscreant" servers, though, so let's check anyway. -- w
*
* We also check here for totally invalid prefixes (prefixes that are neither
* a valid SID or a valid UUID, so that invalid UUID or SID never makes it
* to the higher level functions. -- B
*/
TreeServer* const server = TreeServer::Get(who);
if (server->GetSocket() != this)
{
ServerInstance->Logs.Debug(MODNAME, "Protocol violation: Fake direction '{}' from connection '{}'", prefix, linkID);
return;
}
// Translate commands coming from servers using an older protocol
if (proto_version < PROTO_NEWEST)
{
if (!PreProcessOldProtocolMessage(who, command, params))
return;
}
ServerCommand* scmd = Utils->Creator->CmdManager.GetHandler(command);
CommandBase* cmdbase = scmd;
Command* cmd = nullptr;
if (!scmd)
{
// Not a special server-to-server command
cmd = ServerInstance->Parser.GetHandler(command);
if (!cmd)
{
if (command == "ERROR")
{
this->Error(params);
return;
}
else if (command == "BURST")
{
// This is sent even when there is no need for it, drop it here for now
return;
}
throw ProtocolException("Unknown command: " + command);
}
cmdbase = cmd;
}
if (params.size() < cmdbase->min_params)
throw ProtocolException("Insufficient parameters");
if ((!params.empty()) && (params.back().empty()) && (!cmdbase->allow_empty_last_param))
{
// 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
if (params.size()-1 < cmdbase->min_params)
return;
params.pop_back();
}
CmdResult res;
ClientProtocol::TagMap tags;
std::string tag;
irc::sepstream tagstream(taglist, ';');
while (tagstream.GetToken(tag))
ProcessTag(who, tag, tags);
CommandBase::Params newparams(params, tags);
if (scmd)
res = scmd->Handle(who, newparams);
else
{
res = cmd->Handle(who, newparams);
if (res == CmdResult::INVALID)
throw ProtocolException("Error in command handler");
}
if (res == CmdResult::SUCCESS)
Utils->RouteCommand(server->GetRoute(), cmdbase, newparams, who);
}
void TreeSocket::OnTimeout()
{
ServerInstance->SNO.WriteGlobalSno('l', "CONNECT: Connection to \002{}\002 timed out.", linkID);
}
void TreeSocket::Close()
{
if (!HasFd())
return;
ServerInstance->GlobalCulls.AddItem(this);
this->BufferedSocket::Close();
SetError("Remote host closed connection");
// Connection closed.
// If the connection is fully up (state CONNECTED)
// then propagate a netsplit to all peers.
if (MyRoot && !MyRoot->IsDead())
MyRoot->SQuit(GetError(), true);
else
ServerInstance->SNO.WriteGlobalSno('l', "Connection to '\002{}\002' failed.", linkID);
time_t server_uptime = ServerInstance->Time() - this->age;
if (server_uptime)
{
std::string timestr = Duration::ToString(server_uptime);
ServerInstance->SNO.WriteGlobalSno('l', "Connection to '\002{}\002' was established for {}", linkID, timestr);
}
}
void TreeSocket::FinishAuth(const std::string& remotename, const std::string& remotesid, const std::string& remotedesc, bool hidden)
{
this->LinkState = CONNECTED;
Utils->timeoutlist.erase(this);
linkID = remotename;
MyRoot = new TreeServer(remotename, remotedesc, remotesid, Utils->TreeRoot, this, hidden);
// Mark the server as bursting
MyRoot->BeginBurst();
this->DoBurst(MyRoot);
CommandServer::Builder(MyRoot).Forward(MyRoot);
}
