Import the anticaps module from inspircd-extras.

1 files changed, 309 insertions, 0 deletions

diff --git a/src/modules/m_anticaps.cpp b/src/modules/m_anticaps.cpp
new file mode 100644
index 000000000..6b0c192be
--- /dev/null
+++ b/src/modules/m_anticaps.cpp
@@ -0,0 +1,309 @@
+/*
+ * InspIRCd -- Internet Relay Chat Daemon
+ *
+ *   Copyright (C) 2017 Peter Powell <petpow@saberuk.com>
+ *
+ * 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 "modules/exemption.h"
+
+enum AntiCapsMethod
+{
+	ACM_BAN,
+	ACM_BLOCK,
+	ACM_MUTE,
+	ACM_KICK,
+	ACM_KICK_BAN
+};
+
+class AntiCapsSettings
+{
+ public:
+	const AntiCapsMethod method;
+	const uint16_t minlen;
+	const uint8_t percent;
+
+	AntiCapsSettings(const AntiCapsMethod& Method, const uint16_t& MinLen, const uint8_t& Percent)
+		: method(Method)
+		, minlen(MinLen)
+		, percent(Percent)
+	{
+	}
+};
+
+class AntiCapsMode : public ParamMode<AntiCapsMode, SimpleExtItem<AntiCapsSettings> >
+{
+ private:
+	bool ParseMethod(irc::sepstream& stream, AntiCapsMethod& method)
+	{
+		std::string methodstr;
+		if (!stream.GetToken(methodstr))
+			return false;
+
+		if (irc::equals(methodstr, "ban"))
+			method = ACM_BAN;
+		else if (irc::equals(methodstr, "block"))
+			method = ACM_BLOCK;
+		else if (irc::equals(methodstr, "mute"))
+			method = ACM_MUTE;
+		else if (irc::equals(methodstr, "kick"))
+			method = ACM_KICK;
+		else if (irc::equals(methodstr, "kickban"))
+			method = ACM_KICK_BAN;
+		else
+			return false;
+
+		return true;
+	}
+
+	bool ParseMinimumLength(irc::sepstream& stream, uint16_t& minlen)
+	{
+		std::string minlenstr;
+		if (!stream.GetToken(minlenstr))
+			return false;
+
+		uint16_t result = atoi(minlenstr.c_str());
+		if (result < 1 || result > ServerInstance->Config->Limits.MaxLine)
+			return false;
+
+		minlen = result;
+		return true;
+	}
+
+	bool ParsePercent(irc::sepstream& stream, uint8_t& percent)
+	{
+		std::string percentstr;
+		if (!stream.GetToken(percentstr))
+			return false;
+
+		int result = atoi(percentstr.c_str());
+		if (result < 1 || result > 100)
+			return false;
+
+		percent = result;
+		return true;
+	}
+
+ public:
+	AntiCapsMode(Module* Creator)
+		: ParamMode<AntiCapsMode, SimpleExtItem<AntiCapsSettings> >(Creator, "anticaps", 'B')
+	{
+	}
+
+	ModeAction OnSet(User* source, Channel* channel, std::string& parameter)
+	{
+		irc::sepstream stream(parameter, ':');
+		AntiCapsMethod method;
+		uint16_t minlen;
+		uint8_t percent;
+
+		// Attempt to parse the method.
+		if (!ParseMethod(stream, method) || !ParseMinimumLength(stream, minlen) || !ParsePercent(stream, percent))
+		{
+			source->WriteNumeric(Numerics::InvalidModeParameter(channel, this, parameter, "Invalid anticaps mode parameter. Syntax: <ban|block|mute|kick|kickban>:{minlen}:{percent}."));
+			return MODEACTION_DENY;
+		}
+
+		ext.set(channel, new AntiCapsSettings(method, minlen, percent));
+		return MODEACTION_ALLOW;
+	}
+
+	void SerializeParam(Channel* chan, const AntiCapsSettings* acs, std::string& out)
+	{
+		switch (acs->method)
+		{
+			case ACM_BAN:
+				out.append("ban");
+				break;
+			case ACM_BLOCK:
+				out.append("block");
+				break;
+			case ACM_MUTE:
+				out.append("mute");
+				break;
+			case ACM_KICK:
+				out.append("kick");
+				break;
+			case ACM_KICK_BAN:
+				out.append("kickban");
+				break;
+			default:
+				out.append("unknown~");
+				out.append(ConvToStr(acs->method));
+				break;
+		}
+		out.push_back(':');
+		out.append(ConvToStr(acs->minlen));
+		out.push_back(':');
+		out.append(ConvToStr(acs->percent));
+	}
+};
+
+class ModuleAntiCaps : public Module
+{
+ private:
+	CheckExemption::EventProvider exemptionprov;
+	std::bitset<UCHAR_MAX> uppercase;
+	std::bitset<UCHAR_MAX> lowercase;
+	AntiCapsMode mode;
+
+	void CreateBan(Channel* channel, User* user, bool mute)
+	{
+		std::string banmask(mute ? "m:" : "");
+		banmask.append("*!*@");
+		banmask.append(user->GetDisplayedHost());
+
+		Modes::ChangeList changelist;
+		changelist.push_add(ServerInstance->Modes->FindMode('b', MODETYPE_CHANNEL), banmask);
+		ServerInstance->Modes->Process(ServerInstance->FakeClient, channel, NULL, changelist);
+	}
+
+	void InformUser(Channel* channel, User* user, const std::string& message)
+	{
+		user->WriteNumeric(ERR_CANNOTSENDTOCHAN, channel, message + " and was blocked.");
+	}
+
+ public:
+	ModuleAntiCaps()
+		: exemptionprov(this)
+		, mode(this)
+	{
+	}
+
+	void ReadConfig(ConfigStatus&) CXX11_OVERRIDE
+	{
+		ConfigTag* tag = ServerInstance->Config->ConfValue("anticaps");
+
+		uppercase.reset();
+		const std::string upper = tag->getString("uppercase", "ABCDEFGHIJKLMNOPQRSTUVWXYZ");
+		for (std::string::const_iterator iter = upper.begin(); iter != upper.end(); ++iter)
+			uppercase.set(static_cast<unsigned char>(*iter));
+
+		lowercase.reset();
+		const std::string lower = tag->getString("lowercase", "abcdefghijklmnopqrstuvwxyz");
+		for (std::string::const_iterator iter = lower.begin(); iter != lower.end(); ++iter)
+			lowercase.set(static_cast<unsigned char>(*iter));
+	}
+
+	ModResult OnUserPreMessage(User* user, const MessageTarget& target, MessageDetails& details) CXX11_OVERRIDE
+	{
+		// We only want to operate on messages from local users.
+		if (!IS_LOCAL(user))
+			return MOD_RES_PASSTHRU;
+
+		// The mode can only be applied to channels.
+		if (target.type != MessageTarget::TYPE_CHANNEL)
+			return MOD_RES_PASSTHRU;
+
+		// We only act if the channel has the mode set.
+		Channel* channel = target.Get<Channel>();
+		if (!channel->IsModeSet(&mode))
+			return MOD_RES_PASSTHRU;
+
+		// If the user is exempt from anticaps then we don't need
+		// to do anything else.
+		ModResult result = CheckExemption::Call(exemptionprov, user, channel, "anticaps");
+			if (result == MOD_RES_ALLOW)
+			return MOD_RES_PASSTHRU;
+
+		// If the message is a CTCP then we skip it unless it is
+		// an ACTION in which case we skip the prefix and suffix.
+		std::string::const_iterator text_begin = details.text.begin();
+		std::string::const_iterator text_end = details.text.end();
+		if (details.text[0] == '\1')
+		{
+			// If the CTCP is not an action then skip it.
+			if (details.text.compare(0, 8, "\1ACTION ", 8))
+				return MOD_RES_PASSTHRU;
+
+			// Skip the CTCP message characters.
+			text_begin += 8;
+			if (*details.text.rbegin() == '\1')
+				text_end -= 1;
+		}
+
+		// Retrieve the anticaps config. This should never be
+		// null but its better to be safe than sorry.
+		AntiCapsSettings* config = mode.ext.get(channel);
+		if (!config)
+			return MOD_RES_PASSTHRU;
+
+		// If the message is shorter than the minimum length then
+		// we don't need to do anything else.
+		size_t length = std::distance(text_begin, text_end);
+		if (length < config->minlen)
+			return MOD_RES_PASSTHRU;
+
+		// Count the characters to see how many upper case and
+		// ignored (non upper or lower) characters there are.
+		size_t upper = 0;
+		for (std::string::const_iterator iter = text_begin; iter != text_end; ++iter)
+		{
+			unsigned char chr = static_cast<unsigned char>(*iter);
+			if (uppercase.test(chr))
+				upper += 1;
+			else if (!lowercase.test(chr))
+				length -= 1;
+		}
+
+		// If the message was entirely symbols then the message
+		// can't contain any upper case letters.
+		if (length == 0)
+			return MOD_RES_PASSTHRU;
+
+		// Calculate the percentage.
+		double percent = round((upper * 100) / length);
+		if (percent < config->percent)
+			return MOD_RES_PASSTHRU;
+
+		const std::string message = InspIRCd::Format("Your message exceeded the %d%% upper case character threshold for %s",
+			config->percent, channel->name.c_str());
+
+		switch (config->method)
+		{
+			case ACM_BAN:
+				InformUser(channel, user, message);
+				CreateBan(channel, user, false);
+				break;
+
+			case ACM_BLOCK:
+				InformUser(channel, user, message);
+				break;
+
+			case ACM_MUTE:
+				InformUser(channel, user, message);
+				CreateBan(channel, user, true);
+				break;
+
+			case ACM_KICK:
+				channel->KickUser(ServerInstance->FakeClient, user, message);
+				break;
+
+			case ACM_KICK_BAN:
+				CreateBan(channel, user, false);
+				channel->KickUser(ServerInstance->FakeClient, user, message);
+				break;
+		}
+		return MOD_RES_DENY;
+	}
+
+	Version GetVersion() CXX11_OVERRIDE
+	{
+		return Version("Provides support for punishing users that send capitalised messages.", VF_COMMON|VF_VENDOR);
+	}
+};
+
+MODULE_INIT(ModuleAntiCaps)