1 files changed, 212 insertions, 0 deletions
diff --git a/src/modules/m_codepage.cpp b/src/modules/m_codepage.cpp
new file mode 100644
index 000000000..1c3ac02da
--- /dev/null
+++ b/src/modules/m_codepage.cpp
@@ -0,0 +1,212 @@
+/*
+ * InspIRCd -- Internet Relay Chat Daemon
+ *
+ *   Copyright (C) 2020 Sadie Powell <sadie@witchery.services>
+ *   Copyright (C) 2014 Googolplexed <googol@googolplexed.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"
+
+typedef std::bitset<UCHAR_MAX + 1> AllowedChars;
+
+namespace
+{
+	// The characters which are allowed in nicknames.
+	AllowedChars allowedchars;
+
+	// The characters which are allowed at the front of a nickname.
+	AllowedChars allowedfrontchars;
+
+	// The mapping of lower case characters to upper case characters.
+	unsigned char casemap[UCHAR_MAX];
+
+	bool IsValidNick(const std::string& nick)
+	{
+		if (nick.empty() || nick.length() > ServerInstance->Config->Limits.NickMax)
+			return false;
+
+		for (std::string::const_iterator iter = nick.begin(); iter != nick.end(); ++iter)
+		{
+			unsigned char chr = static_cast<unsigned char>(*iter);
+
+			// Check that the character is allowed at the front of the nick.
+			if (iter == nick.begin() && !allowedfrontchars[chr])
+				return false;
+
+			// Check that the character is allowed in the nick.
+			if (!allowedchars[chr])
+				return false;
+		}
+
+		return true;
+	}
+}
+
+class ModuleCodepage
+	: public Module
+{
+ private:
+	// The character map which was set before this module was loaded.
+	const unsigned char* origcasemap;
+
+	// The IsNick handler which was set before this module was loaded.
+	TR1NS::function<bool(const std::string&)> origisnick;
+
+	template <typename T>
+	void RehashHashmap(T& hashmap)
+	{
+		T newhash(hashmap.bucket_count());
+		for (typename T::const_iterator i = hashmap.begin(); i != hashmap.end(); ++i)
+			newhash.insert(std::make_pair(i->first, i->second));
+		hashmap.swap(newhash);
+	}
+
+	void CheckInvalidNick()
+	{
+		const UserManager::LocalList& list = ServerInstance->Users.GetLocalUsers();
+		for (UserManager::LocalList::const_iterator iter = list.begin(); iter != list.end(); ++iter)
+		{
+			LocalUser* user = *iter;
+			if (user->nick != user->uuid && !ServerInstance->IsNick(user->nick))
+				user->ChangeNick(user->uuid);
+		}
+	}
+
+	void CheckRehash(unsigned char* prevmap)
+	{
+		if (!memcmp(prevmap, national_case_insensitive_map, sizeof(origcasemap)))
+			return;
+
+		RehashHashmap(ServerInstance->Users.clientlist);
+		RehashHashmap(ServerInstance->Users.uuidlist);
+		RehashHashmap(ServerInstance->chanlist);
+	}
+
+ public:
+	ModuleCodepage()
+		: origcasemap(national_case_insensitive_map)
+		, origisnick(ServerInstance->IsNick)
+	{
+	}
+
+	~ModuleCodepage()
+	{
+		ServerInstance->IsNick = origisnick;
+		CheckInvalidNick();
+
+		national_case_insensitive_map = origcasemap;
+		CheckRehash(casemap);
+	}
+
+	void ReadConfig(ConfigStatus& status) CXX11_OVERRIDE
+	{
+		const std::string name = ServerInstance->Config->ConfValue("codepage")->getString("name");
+		if (name.empty())
+			throw ModuleException("<codepage:name> is a required field!");
+
+		AllowedChars newallowedchars;
+		AllowedChars newallowedfrontchars;
+		ConfigTagList cpchars = ServerInstance->Config->ConfTags("cpchars");
+		for (ConfigIter i = cpchars.first; i != cpchars.second; ++i)
+		{
+			ConfigTag* tag = i->second;
+
+			unsigned char begin = tag->getUInt("begin", tag->getUInt("index", 0), 1, UCHAR_MAX);
+			if (!begin)
+				throw ModuleException("<cpchars> tag without index or begin specified at " + tag->getTagLocation());
+	
+			unsigned char end = tag->getUInt("end", begin, 1, UCHAR_MAX);
+			if (begin > end)
+				throw ModuleException("<cpchars:begin> must be lower than <cpchars:end> at " + tag->getTagLocation());
+
+			bool front = tag->getBool("front", false);
+			for (unsigned short pos = begin; pos <= end; ++pos)
+			{
+				if (pos == '\n' || pos == '\r' || pos == ' ')
+				{
+					throw ModuleException(InspIRCd::Format("<cpchars> tag contains a forbidden character: %u at %s",
+						pos, tag->getTagLocation().c_str()));
+				}
+
+				if (front && (pos == ':' || isdigit(pos)))
+				{
+					throw ModuleException(InspIRCd::Format("<cpchars> tag contains a forbidden front character: %u at %s",
+						pos, tag->getTagLocation().c_str()));
+				}
+
+				newallowedchars.set(pos);
+				newallowedfrontchars.set(pos, front);
+				ServerInstance->Logs->Log(MODNAME, LOG_DEBUG, "Marked %u (%c) as allowed (front: %s)",
+					pos, pos, front ? "yes" : "no");
+			}
+		}
+
+		unsigned char newcasemap[UCHAR_MAX];
+		for (size_t i = 0; i < UCHAR_MAX; ++i)
+			newcasemap[i] = i;
+		ConfigTagList cpcase = ServerInstance->Config->ConfTags("cpcase");
+		for (ConfigIter i = cpcase.first; i != cpcase.second; ++i)
+		{
+			ConfigTag* tag = i->second;
+
+			unsigned char lower = tag->getUInt("lower", 0, 1, UCHAR_MAX);
+			if (!lower)
+				throw ModuleException("<cpcase:lower> is required at " + tag->getTagLocation());
+
+			unsigned char upper = tag->getUInt("upper", 0, 1, UCHAR_MAX);
+			if (!upper)
+				throw ModuleException("<cpcase:upper> is required at " + tag->getTagLocation());
+
+			newcasemap[upper] = lower;
+			ServerInstance->Logs->Log(MODNAME, LOG_DEBUG, "Marked %u (%c) as the lower case version of %u (%c)",
+				lower, lower, upper, upper);
+		}
+
+		std::swap(allowedchars, newallowedchars);
+		std::swap(allowedfrontchars, newallowedfrontchars);
+		std::swap(casemap, newcasemap);
+
+		ServerInstance->IsNick = &IsValidNick;
+		CheckInvalidNick();
+
+		ServerInstance->Config->CaseMapping = name;
+		national_case_insensitive_map = casemap;
+		CheckRehash(newcasemap);
+	}
+
+	Version GetVersion() CXX11_OVERRIDE
+	{
+		std::stringstream linkdata;
+
+		linkdata << "front=";
+		for (size_t i = 0; i < allowedfrontchars.size(); ++i)
+			if (allowedfrontchars[i])
+				linkdata << static_cast<unsigned char>(i);
+
+		linkdata << "&middle=";
+		for (size_t i = 0; i < allowedchars.size(); ++i)
+			if (allowedchars[i])
+				linkdata << static_cast<unsigned char>(i);
+
+		linkdata << "&map=";
+		for (size_t i = 0; i < sizeof(casemap); ++i)
+			if (casemap[i] != i)
+				linkdata << static_cast<unsigned char>(i) << casemap[i] << ',';
+
+		return Version("Provides support for custom 8-bit codepages", VF_COMMON | VF_VENDOR, linkdata.str());
+	}
+};
+MODULE_INIT(ModuleCodepage)