2 * InspIRCd -- Internet Relay Chat Daemon
4 * Copyright (C) 2009 Daniel De Graaf <danieldg@inspircd.org>
5 * Copyright (C) 2008 Robin Burchell <robin+git@viroteck.net>
7 * This file is part of InspIRCd. InspIRCd is free software: you can
8 * redistribute it and/or modify it under the terms of the GNU General Public
9 * License as published by the Free Software Foundation, version 2.
11 * This program is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
13 * FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
16 * You should have received a copy of the GNU General Public License
17 * along with this program. If not, see <http://www.gnu.org/licenses/>.
23 #include "treesocket.h"
24 #include "treeserver.h"
26 #include "commandbuilder.h"
29 * Yes, this function looks a little ugly.
30 * However, in some circumstances we may not have a User, so we need to do things this way.
31 * Returns 1 if colliding local client, 2 if colliding remote, 3 if colliding both.
32 * Sends SAVEs as appropriate and forces nick change of the user 'u' if our side loses or if both lose.
33 * Does not change the nick of the user that is trying to claim the nick of 'u', i.e. the "remote" user.
35 int SpanningTreeUtilities::DoCollision(User* u, TreeServer* server, time_t remotets, const std::string& remoteident, const std::string& remoteip, const std::string& remoteuid)
37 // At this point we're sure that a collision happened, increment the counter regardless of who wins
38 ServerInstance->stats.Collisions++;
41 * Under old protocol rules, we would have had to kill both clients.
43 * These days, we have UID. And, so what we do is, force nick change client(s)
44 * involved according to timestamp rules.
48 * Force nick change on OLDER timestamped client
50 * Force nick change on NEWER timestamped client
54 * This stops abusive use of collisions, simplifies problems with loops, and so on.
57 bool bChangeLocal = true;
58 bool bChangeRemote = true;
60 /* for brevity, don't use the User - use defines to avoid any copy */
61 #define localts u->age
62 #define localident u->ident
63 #define localip u->GetIPString()
65 /* mmk. let's do this again. */
66 if (remotets == localts)
68 /* equal. fuck them both! do nada, let the handler at the bottom figure this out. */
72 /* fuck. now it gets complex. */
74 /* first, let's see if ident@host matches. */
75 bool SamePerson = (localident == remoteident)
76 && (localip == remoteip);
79 * if ident@ip is equal, and theirs is newer, or
80 * ident@ip differ, and ours is newer
82 if((SamePerson && remotets < localts) ||
83 (!SamePerson && remotets > localts))
85 /* remote needs to change */
90 /* ours needs to change */
91 bChangeRemote = false;
96 * Cheat a little here. Instead of a dedicated command to change UID,
97 * use SAVE and accept the losing client with its UID (as we know the SAVE will
98 * not fail under any circumstances -- UIDs are netwide exclusive).
100 * This means that each side of a collide will generate one extra NICK back to where
101 * they have just linked (and where it got the SAVE from), however, it will
102 * be dropped harmlessly as it will come in as :928AAAB NICK 928AAAB, and we already
103 * have 928AAAB's nick set to that.
110 * Local-side nick needs to change. Just in case we are hub, and
111 * this "local" nick is actually behind us, send an SAVE out.
113 CmdBuilder params("SAVE");
114 params.push_back(u->uuid);
115 params.push_back(ConvToStr(u->age));
118 u->ChangeNick(u->uuid);
126 * remote side needs to change. If this happens, we will modify
127 * the UID or halt the propagation of the nick change command,
128 * so other servers don't need to see the SAVE
130 TreeSocket* sock = server->GetSocket();
131 sock->WriteLine(CmdBuilder("SAVE").push(remoteuid).push_int(remotets));