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/*
* InspIRCd -- Internet Relay Chat Daemon
*
* Copyright (C) 2009 Daniel De Graaf <danieldg@inspircd.org>
* Copyright (C) 2008 Robin Burchell <robin+git@viroteck.net>
*
* 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 "treesocket.h"
#include "treeserver.h"
#include "utils.h"
#include "commandbuilder.h"
/*
* Yes, this function looks a little ugly.
* However, in some circumstances we may not have a User, so we need to do things this way.
* Returns 1 if colliding local client, 2 if colliding remote, 3 if colliding both.
* Sends SAVEs as appropriate and forces nick change of the user 'u' if our side loses or if both lose.
* Does not change the nick of the user that is trying to claim the nick of 'u', i.e. the "remote" user.
*/
int SpanningTreeUtilities::DoCollision(User* u, TreeServer* server, time_t remotets, const std::string& remoteident, const std::string& remoteip, const std::string& remoteuid)
{
// At this point we're sure that a collision happened, increment the counter regardless of who wins
ServerInstance->stats.Collisions++;
/*
* Under old protocol rules, we would have had to kill both clients.
* Really, this sucks.
* These days, we have UID. And, so what we do is, force nick change client(s)
* involved according to timestamp rules.
*
* RULES:
* user@ip equal:
* Force nick change on OLDER timestamped client
* user@ip differ:
* Force nick change on NEWER timestamped client
* TS EQUAL:
* FNC both.
*
* This stops abusive use of collisions, simplifies problems with loops, and so on.
* -- w00t
*/
bool bChangeLocal = true;
bool bChangeRemote = true;
// If the timestamps are not equal only one of the users has to change nick,
// otherwise both have to change
const time_t localts = u->age;
if (remotets != localts)
{
/* first, let's see if ident@host matches. */
const std::string& localident = u->ident;
const std::string& localip = u->GetIPString();
bool SamePerson = (localident == remoteident)
&& (localip == remoteip);
/*
* if ident@ip is equal, and theirs is newer, or
* ident@ip differ, and ours is newer
*/
if((SamePerson && remotets < localts) ||
(!SamePerson && remotets > localts))
{
// Only remote needs to change
bChangeLocal = false;
}
else
{
// Only ours needs to change
bChangeRemote = false;
}
}
/*
* Send SAVE and accept the losing client with its UID (as we know the SAVE will
* not fail under any circumstances -- UIDs are netwide exclusive).
*
* This means that each side of a collide will generate one extra NICK back to where
* they have just linked (and where it got the SAVE from), however, it will
* be dropped harmlessly as it will come in as :928AAAB NICK 928AAAB, and we already
* have 928AAAB's nick set to that.
* -- w00t
*/
if (bChangeLocal)
{
/*
* Local-side nick needs to change. Just in case we are hub, and
* this "local" nick is actually behind us, send a SAVE out.
*/
CmdBuilder params("SAVE");
params.push_back(u->uuid);
params.push_back(ConvToStr(u->age));
params.Broadcast();
u->ChangeNick(u->uuid);
if (!bChangeRemote)
return 1;
}
if (bChangeRemote)
{
/*
* Remote side needs to change. If this happens, we modify the UID or NICK and
* send back a SAVE to the source.
*/
TreeSocket* sock = server->GetSocket();
sock->WriteLine(CmdBuilder("SAVE").push(remoteuid).push_int(remotets));
if (!bChangeLocal)
return 2;
}
return 3;
}
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