/*
* InspIRCd -- Internet Relay Chat Daemon
*
* Copyright (C) 2018-2024 Sadie Powell <sadie@sadiepowell.dev>
*
* 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 <cmath>
#include "inspircd.h"
#include "extension.h"
#include "modules/exemption.h"
#include "numerichelper.h"
enum class AntiCapsMethod
: uint8_t
{
BAN,
BLOCK,
MUTE,
KICK,
KICK_BAN,
};
class AntiCapsSettings final
{
public:
const AntiCapsMethod method;
const uint16_t minlen;
const uint8_t percent;
AntiCapsSettings(const AntiCapsMethod& m, uint16_t ml, uint8_t p)
: method(m)
, minlen(ml)
, percent(p)
{
}
static bool Parse(irc::sepstream& stream, AntiCapsMethod& method, uint16_t& minlen, uint8_t& percent)
{
return ParseMethod(stream, method) && ParseMinimumLength(stream, minlen) && ParsePercent(stream, percent);
}
static bool ParseMethod(irc::sepstream& stream, AntiCapsMethod& method)
{
std::string methodstr;
if (!stream.GetToken(methodstr))
return false;
if (irc::equals(methodstr, "ban"))
method = AntiCapsMethod::BAN;
else if (irc::equals(methodstr, "block"))
method = AntiCapsMethod::BLOCK;
else if (irc::equals(methodstr, "mute"))
method = AntiCapsMethod::MUTE;
else if (irc::equals(methodstr, "kick"))
method = AntiCapsMethod::KICK;
else if (irc::equals(methodstr, "kickban"))
method = AntiCapsMethod::KICK_BAN;
else
return false;
return true;
}
static bool ParseMinimumLength(irc::sepstream& stream, uint16_t& minlen)
{
std::string minlenstr;
if (!stream.GetToken(minlenstr))
return false;
uint16_t result = ConvToNum<uint16_t>(minlenstr);
if (result < 1 || result > ServerInstance->Config->Limits.MaxLine)
return false;
minlen = result;
return true;
}
static bool ParsePercent(irc::sepstream& stream, uint8_t& percent)
{
std::string percentstr;
if (!stream.GetToken(percentstr))
return false;
uint8_t result = ConvToNum<uint8_t>(percentstr);
if (result < 1 || result > 100)
return false;
percent = result;
return true;
}
};
class AntiCapsMode final
: public ParamMode<AntiCapsMode, SimpleExtItem<AntiCapsSettings>>
{
public:
AntiCapsMode(Module* Creator)
: ParamMode<AntiCapsMode, SimpleExtItem<AntiCapsSettings>>(Creator, "anticaps", 'B')
{
syntax = "{ban|block|mute|kick|kickban}:<minlen>:<percent>";
}
bool OnSet(User* source, Channel* channel, std::string& parameter) override
{
irc::sepstream stream(parameter, ':');
AntiCapsMethod method;
uint16_t minlen;
uint8_t percent;
// Attempt to parse the settings.
if (!AntiCapsSettings::Parse(stream, method, minlen, percent))
{
source->WriteNumeric(Numerics::InvalidModeParameter(channel, this, parameter));
return false;
}
ext.SetFwd(channel, method, minlen, percent);
return true;
}
void SerializeParam(Channel* chan, const AntiCapsSettings* acs, std::string& out)
{
switch (acs->method)
{
case AntiCapsMethod::BAN:
out.append("ban");
break;
case AntiCapsMethod::BLOCK:
out.append("block");
break;
case AntiCapsMethod::MUTE:
out.append("mute");
break;
case AntiCapsMethod::KICK:
out.append("kick");
break;
case AntiCapsMethod::KICK_BAN:
out.append("kickban");
break;
}
out.push_back(':');
out.append(ConvToStr(acs->minlen));
out.push_back(':');
out.append(ConvToStr<uint16_t>(acs->percent));
}
};
class ModuleAntiCaps final
: public Module
{
private:
ChanModeReference banmode;
CheckExemption::EventProvider exemptionprov;
CharState uppercase;
CharState lowercase;
AntiCapsMode mode;
std::string message;
void CreateBan(Channel* channel, User* user, bool mute)
{
std::string banmask(mute ? "m:*!" : "*!");
banmask.append(user->GetBanUser(false));
banmask.append("@");
banmask.append(user->GetDisplayedHost());
Modes::ChangeList changelist;
changelist.push_add(*banmode, banmask);
ServerInstance->Modes.Process(ServerInstance->FakeClient, channel, nullptr, changelist);
}
static void InformUser(Channel* channel, User* user, const std::string& msg)
{
user->WriteNumeric(Numerics::CannotSendTo(channel, msg));
}
public:
ModuleAntiCaps()
: Module(VF_VENDOR | VF_COMMON, "Adds channel mode B (anticaps) which allows channels to block messages which are excessively capitalised.")
, banmode(this, "ban")
, exemptionprov(this)
, mode(this)
{
}
void ReadConfig(ConfigStatus&) override
{
const auto& tag = ServerInstance->Config->ConfValue("anticaps");
uppercase.reset();
for (const auto chr : tag->getString("uppercase", "ABCDEFGHIJKLMNOPQRSTUVWXYZ", 1))
uppercase.set(static_cast<unsigned char>(chr));
lowercase.reset();
for (const auto chr : tag->getString("lowercase", "abcdefghijklmnopqrstuvwxyz", 1))
lowercase.set(static_cast<unsigned char>(chr));
message = tag->getString("message", "Your message exceeded the %percent%%% upper case character threshold for %channel%", 1);
}
ModResult OnUserPreMessage(User* user, MessageTarget& target, MessageDetails& details) 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.
auto* 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 = exemptionprov.Check(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 just check against the body.
std::string_view ctcpname;
std::string_view msgbody(details.text);
if (details.IsCTCP(ctcpname, msgbody))
{
// If the CTCP is not an action then skip it.
if (!irc::equals(ctcpname, "ACTION"))
return MOD_RES_PASSTHRU;
}
// 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 = msgbody.length();
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;
size_t lower = 0;
for (const auto chr : msgbody)
{
if (uppercase.test(static_cast<unsigned char>(chr)))
upper += 1;
else if (lowercase.test(static_cast<unsigned char>(chr)))
lower += 1;
else
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 auto msg = Template::Replace(message, {
{ "channel", channel->name },
{ "lower", ConvToStr(lower) },
{ "minlen", ConvToStr(config->minlen) },
{ "percent", ConvToStr<uint16_t>(config->percent) },
{ "punctuation", ConvToStr(msgbody.length() - upper - lower) },
{ "upper", ConvToStr(upper) },
});
switch (config->method)
{
case AntiCapsMethod::BAN:
InformUser(channel, user, msg);
CreateBan(channel, user, false);
break;
case AntiCapsMethod::BLOCK:
InformUser(channel, user, msg);
break;
case AntiCapsMethod::MUTE:
InformUser(channel, user, msg);
CreateBan(channel, user, true);
break;
case AntiCapsMethod::KICK:
channel->KickUser(ServerInstance->FakeClient, user, msg);
break;
case AntiCapsMethod::KICK_BAN:
CreateBan(channel, user, false);
channel->KickUser(ServerInstance->FakeClient, user, msg);
break;
}
return MOD_RES_DENY;
}
};
MODULE_INIT(ModuleAntiCaps)
