Shuffle the modules about a bit.

1 files changed, 131 insertions, 0 deletions

diff --git a/modules/spanningtree/nickcollide.cpp b/modules/spanningtree/nickcollide.cpp
new file mode 100644
index 000000000..69e804f5b
--- /dev/null
+++ b/modules/spanningtree/nickcollide.cpp
@@ -0,0 +1,131 @@
+/*
+ * InspIRCd -- Internet Relay Chat Daemon
+ *
+ *   Copyright (C) 2019, 2021-2023 Sadie Powell <sadie@witchery.services>
+ *   Copyright (C) 2013-2015 Attila Molnar <attilamolnar@hush.com>
+ *   Copyright (C) 2012 Robby <robby@chatbelgie.be>
+ *   Copyright (C) 2009 Uli Schlachter <psychon@znc.in>
+ *   Copyright (C) 2009 Daniel De Graaf <danieldg@inspircd.org>
+ *   Copyright (C) 2008, 2010 Craig Edwards <brain@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"
+#include "commands.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 true if remote or both lost, false otherwise.
+ * 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.
+ */
+bool SpanningTreeUtilities::DoCollision(User* u, TreeServer* server, time_t remotets, const std::string& remoteuser, const std::string& remoteip, const std::string& remoteuid, const char* collidecmd)
+{
+	// 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->nickchanged;
+	if (remotets != localts)
+	{
+		/* first, let's see if user@host matches. */
+		const std::string& localuser = u->GetRealUser();
+		const std::string& localip = u->GetAddress();
+		bool SamePerson = (localuser == remoteuser)
+				&& (localip == remoteip);
+
+		/*
+		 * if user@ip is equal, and theirs is newer, or
+		 * user@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;
+		}
+	}
+
+	ServerInstance->Logs.Debug(MODNAME, "Nick collision on \"{}\" caused by {}: {}/{}/{}@{} {} <-> {}/{}/{}@{} {}", u->nick, collidecmd,
+		u->uuid, localts, u->GetRealUser(), u->GetAddress(), bChangeLocal,
+		remoteuid, remotets, remoteuser, remoteip, bChangeRemote);
+
+	/*
+	 * 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(u->uuid);
+		params.push(ConvToStr(u->nickchanged));
+		params.Broadcast();
+
+		u->ChangeNick(u->uuid, CommandSave::SavedTimestamp);
+	}
+	if (bChangeRemote)
+	{
+		/*
+		 * Remote side needs to change. If this happens, we modify the UID or NICK and
+		 * send back a SAVE to the source.
+		 */
+		CmdBuilder("SAVE").push(remoteuid).push_int(remotets).Unicast(server->ServerUser);
+	}
+
+	return bChangeRemote;
+}