Add the new implementation of the silence module.

This module has significant improvements on the previous one:
 * Flags which actually make sense.
 * Better compatibility with other SILENCE implementations.
 * Support for blocking CTCPs.
 * Support for blocking TAGMSGs.

2 files changed, 464 insertions, 0 deletions

diff --git a/docs/conf/helpop.conf.example b/docs/conf/helpop.conf.example
index 3578f0683..c0dbdc45f 100644
--- a/docs/conf/helpop.conf.example
+++ b/docs/conf/helpop.conf.example
@@ -145,6 +145,32 @@ E.g. '/RMODE #channel b m:*' will remove all mute extbans on the channel.">
 This behaves identically to /REMOVE. /REMOVE is a built-in mIRC command
 which caused trouble for some users.">
 
+<helpop key="silence" value="/SILENCE [(+|-)<mask> [CcdiNnPpsTtx]+]
+
+A server-side ignore of the given n!u@h mask. If the optional flags field is
+specified then it must contain one or more flags which specify what kind of
+messages should be blocked and how they should be blocked.
+
+/SILENCE - Shows a list of silenced masks
+/SILENCE +<mask> [<flags>] - Add a mask
+/SILENCE -<mask> - Remove a mask
+
+Valid SILENCE Flags
+-------------------
+ c    Matches a CTCP targeted at a channel.
+ C    Matches a CTCP targeted at a user.
+ d    Default behaviour; equivalent to CciNnPpTt.
+ i    Matches an invite to a channel.
+ n    Matches a NOTICE targeted at a channel.
+ N    Matches a NOTICE targeted at a user.
+ p    Matches a PRIVMSG targeted at a channel.
+ P    Matches a PRIVMSG targeted at a user.
+ t    Matches a TAGMSG targeted at a channel.
+ T    Matches a TAGMSG targeted at a user.
+ x    Exempt the mask from silence rules.
+
+Any combination of flags is valid.">
+
 <helpop key="knock" value="/KNOCK <channel> :<reason>
 
 Sends a notice to a channel indicating you wish to join.">
diff --git a/src/modules/m_silence.cpp b/src/modules/m_silence.cpp
new file mode 100644
index 000000000..36d024ba5
--- /dev/null
+++ b/src/modules/m_silence.cpp
@@ -0,0 +1,438 @@
+/*
+ * InspIRCd -- Internet Relay Chat Daemon
+ *
+ *   Copyright (C) 2019 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/ctctags.h"
+
+enum
+{
+	// From ircu?
+	RPL_SILELIST = 271,
+	RPL_ENDOFSILELIST = 272,
+	ERR_SILELISTFULL = 511,
+
+	// InspIRCd-specific.
+	ERR_SILENCE = 952
+};
+
+class SilenceEntry
+{
+ public:
+	enum SilenceFlags
+	{
+		// Does nothing; for internal use only.
+		SF_NONE = 0,
+
+		// Exclude users who match this flags ("x").
+		SF_EXEMPT = 1,
+	
+		// 2, 4, 8, 16 are reserved for future use.
+
+		// Matches a NOTICE targeted at a channel ("n").
+		SF_NOTICE_CHANNEL = 32,
+
+		// Matches a NOTICE targeted at a user ("N").
+		SF_NOTICE_USER = 64,
+
+		// Matches a PRIVMSG targeted at a channel ("p").
+		SF_PRIVMSG_CHANNEL = 128,
+
+		// Matches a PRIVMSG targeted at a user ("P").
+		SF_PRIVMSG_USER = 256,
+
+		// Matches a TAGMSG targeted at a channel ("t").
+		SF_TAGMSG_CHANNEL = 512,
+
+		// Matches a TAGMSG targeted at a user ("T").
+		SF_TAGMSG_USER = 1024,
+
+		// Matches a CTCP targeted at a channel ("c").
+		SF_CTCP_CHANNEL = 2048,
+
+		// Matches a CTCP targeted at a user ("C").
+		SF_CTCP_USER = 4096,
+
+		// Matches an invite to a channel ("i").
+		SF_INVITE = 8192,
+
+		// The default if no flags have been specified.
+		SF_DEFAULT = SF_NOTICE_CHANNEL | SF_NOTICE_USER | SF_PRIVMSG_CHANNEL | SF_PRIVMSG_USER | SF_TAGMSG_CHANNEL |
+			SF_TAGMSG_USER | SF_CTCP_CHANNEL | SF_CTCP_USER | SF_INVITE
+	};
+
+	// The flags that this mask is silenced for.
+	uint32_t flags;
+
+	// The mask which is silenced (e.g. *!*@example.com).
+	std::string mask;
+
+	SilenceEntry(uint32_t Flags, const std::string& Mask)
+		: flags(Flags)
+		, mask(Mask)
+	{
+	}
+
+	bool operator <(const SilenceEntry& other) const
+	{
+		if (flags & SF_EXEMPT && other.flags & ~SF_EXEMPT)
+			return true;
+		if (other.flags & SF_EXEMPT && flags & ~SF_EXEMPT)
+			return false;
+		if (flags < other.flags)
+			return true;
+		if (other.flags < flags)
+			return false;
+		return mask < other.mask;
+	}
+
+	// Converts a flag list to a bitmask.
+	static bool FlagsToBits(const std::string& flags, uint32_t& out)
+	{
+		out = SF_NONE;
+		for (std::string::const_iterator flag = flags.begin(); flag != flags.end(); ++flag)
+		{
+			switch (*flag)
+			{
+				case 'C':
+					out |= SF_CTCP_USER;
+					break;
+				case 'c':
+					out |= SF_CTCP_CHANNEL;
+					break;
+				case 'd':
+					out |= SF_DEFAULT;
+					break;
+				case 'i':
+					out |= SF_INVITE;
+					break;
+				case 'N':
+					out |= SF_NOTICE_USER;
+					break;
+				case 'n':
+					out |= SF_NOTICE_CHANNEL;
+					break;
+				case 'P':
+					out |= SF_PRIVMSG_USER;
+					break;
+				case 'p':
+					out |= SF_PRIVMSG_CHANNEL;
+					break;
+				case 'T':
+					out |= SF_TAGMSG_USER;
+					break;
+				case 't':
+					out |= SF_TAGMSG_CHANNEL;
+					break;
+				case 'x':
+					out |= SF_EXEMPT;
+					break;
+				default:
+					out = SF_NONE;
+					return false;
+			}
+		}
+		return true;
+	}
+
+	// Converts a bitmask to a flag list.
+	static std::string BitsToFlags(uint32_t flags)
+	{
+		std::string out;
+		if (flags & SF_CTCP_USER)
+			out.push_back('C');
+		if (flags & SF_CTCP_CHANNEL)
+			out.push_back('c');
+		if (flags & SF_INVITE)
+			out.push_back('i');
+		if (flags & SF_NOTICE_USER)
+			out.push_back('N');
+		if (flags & SF_NOTICE_CHANNEL)
+			out.push_back('n');
+		if (flags & SF_PRIVMSG_USER)
+			out.push_back('P');
+		if (flags & SF_PRIVMSG_CHANNEL)
+			out.push_back('p');
+		if (flags & SF_TAGMSG_CHANNEL)
+			out.push_back('T');
+		if (flags & SF_TAGMSG_USER)
+			out.push_back('t');
+		if (flags & SF_EXEMPT)
+			out.push_back('x');
+		return out;
+	}
+};
+
+typedef insp::flat_set<SilenceEntry> SilenceList;
+
+class SilenceMessage : public ClientProtocol::Message
+{
+ public:
+	SilenceMessage(const std::string& mask, const std::string& flags)
+		: ClientProtocol::Message("SILENCE")
+	{
+		PushParam(mask);
+		PushParamRef(flags);
+	}
+};
+
+class CommandSilence : public SplitCommand
+{
+ private:
+	ClientProtocol::EventProvider msgprov;
+
+	CmdResult AddSilence(LocalUser* user, const std::string& mask, uint32_t flags)
+	{
+		SilenceList* list = ext.get(user);
+		if (list && list->size() > maxsilence)
+		{
+			user->WriteNumeric(ERR_SILELISTFULL, mask, SilenceEntry::BitsToFlags(flags), "Your silence list is full");
+			return CMD_FAILURE;
+		}
+		else if (!list)
+		{
+			// There is no list; create it.
+			list = new SilenceList();
+			ext.set(user, list);
+		}
+
+		if (!list->insert(SilenceEntry(flags, mask)).second)
+		{
+			user->WriteNumeric(ERR_SILENCE, mask, SilenceEntry::BitsToFlags(flags), "The silence entry you specified already exists");
+			return CMD_FAILURE;
+		}
+
+		SilenceMessage msg("+" + mask, SilenceEntry::BitsToFlags(flags));
+		user->Send(msgprov, msg);
+		return CMD_SUCCESS;
+	}
+
+	CmdResult RemoveSilence(LocalUser* user, const std::string& mask, uint32_t flags)
+	{
+		SilenceList* list = ext.get(user);
+		if (list)
+		{
+			for (SilenceList::iterator iter = list->begin(); iter != list->end(); ++iter)
+			{
+				if (!irc::equals(iter->mask, mask) || iter->flags != flags)
+					continue;
+
+				list->erase(iter);
+				SilenceMessage msg("-" + mask, SilenceEntry::BitsToFlags(flags));
+				user->Send(msgprov, msg);
+				return CMD_SUCCESS;
+			}
+		}
+
+		user->WriteNumeric(ERR_SILENCE, mask, SilenceEntry::BitsToFlags(flags), "The silence entry you specified could not be found");
+		return CMD_FAILURE;
+	}
+
+	CmdResult ShowSilenceList(LocalUser* user)
+	{
+		SilenceList* list = ext.get(user);
+		if (list)
+		{
+			for (SilenceList::const_iterator iter = list->begin(); iter != list->end(); ++iter)
+			{
+				user->WriteNumeric(RPL_SILELIST, iter->mask, SilenceEntry::BitsToFlags(iter->flags));
+			}
+		}
+		user->WriteNumeric(RPL_ENDOFSILELIST, "End of silence list");
+		return CMD_SUCCESS;
+	}
+
+ public:
+	SimpleExtItem<SilenceList> ext;
+	unsigned int maxsilence;
+
+	CommandSilence(Module* Creator)
+		: SplitCommand(Creator, "SILENCE")
+		, msgprov(Creator, "SILENCE")
+		, ext("silence_list", ExtensionItem::EXT_USER, Creator)
+	{
+		allow_empty_last_param = false;
+		syntax = "[(+|-)<mask> [CcdiNnPpTtx]]";
+	}
+
+	CmdResult HandleLocal(LocalUser* user, const Params& parameters) CXX11_OVERRIDE
+	{
+		if (parameters.empty())
+			return ShowSilenceList(user);
+
+		// If neither add nor remove are specified we default to add.
+		bool is_remove = parameters[0][0] == '-';
+
+		// If a prefix mask has been given then strip it and clean it up.
+		std::string mask = parameters[0];
+		if (mask[0] == '-' || mask[0] == '+')
+		{
+			mask.erase(0);
+			if (mask.empty())
+				mask.assign("*");
+			ModeParser::CleanMask(mask);
+		}
+
+		// If the user specified a flags then use that. Otherwise, default to blocking
+		// all CTCPs, invites, notices, privmsgs, and invites.
+		uint32_t flags = SilenceEntry::SF_DEFAULT;
+		if (parameters.size() > 1)
+		{
+			if (!SilenceEntry::FlagsToBits(parameters[1], flags))
+			{
+				user->WriteNumeric(ERR_SILENCE, mask, parameters[1], "You specified one or more invalid SILENCE flags");
+				return CMD_FAILURE;
+			}
+			else if (flags == SilenceEntry::SF_EXEMPT)
+			{
+				// The user specified "x" with no other flags which does not make sense; add the "d" flag.
+				flags |= SilenceEntry::SF_DEFAULT;
+			}
+		}
+
+		return is_remove ? RemoveSilence(user, mask, flags) : AddSilence(user, mask, flags);
+	}
+};
+
+class ModuleSilence
+	: public Module
+	, public CTCTags::EventListener
+{
+ private:
+	bool exemptuline;
+	CommandSilence cmd;
+
+	ModResult BuildChannelExempts(User* source, Channel* channel, SilenceEntry::SilenceFlags flag, CUList& exemptions)
+	{
+		const Channel::MemberMap& members = channel->GetUsers();
+		for (Channel::MemberMap::const_iterator member = members.begin(); member != members.end(); ++member)
+		{
+			if (!CanReceiveMessage(source, member->first, flag))
+				exemptions.insert(member->first);
+		}
+		return MOD_RES_PASSTHRU;
+	}
+
+	bool CanReceiveMessage(User* source, User* target, SilenceEntry::SilenceFlags flag)
+	{
+		// Servers handle their own clients.
+		if (!IS_LOCAL(target))
+			return true;
+
+		if (exemptuline && source->server->IsULine())
+			return true;
+
+		SilenceList* list = cmd.ext.get(target);
+		if (!list)
+			return true;
+
+		for (SilenceList::iterator iter = list->begin(); iter != list->end(); ++iter)
+		{
+			if (!(iter->flags & flag))
+				continue;
+
+			if (InspIRCd::Match(source->GetFullHost(), iter->mask))
+				return iter->flags & SilenceEntry::SF_EXEMPT;
+		}
+
+		return true;
+	}
+
+ public:
+	ModuleSilence()
+		: CTCTags::EventListener(this)
+		, cmd(this)
+	{
+	}
+
+	void ReadConfig(ConfigStatus& status) CXX11_OVERRIDE
+	{
+		ConfigTag* tag = ServerInstance->Config->ConfValue("silence");
+		exemptuline = tag->getBool("exemptuline", true);
+		cmd.maxsilence = tag->getUInt("maxentries", 32, 1);
+	}
+
+	void On005Numeric(std::map<std::string, std::string>& tokens) CXX11_OVERRIDE
+	{
+		tokens["ESILENCE"] = "CcdiNnPpsTtx";
+		tokens["SILENCE"] = ConvToStr(cmd.maxsilence);
+	}
+
+	ModResult OnUserPreInvite(User* source, User* dest, Channel* channel, time_t timeout) CXX11_OVERRIDE
+	{
+		return CanReceiveMessage(source, dest, SilenceEntry::SF_INVITE) ? MOD_RES_PASSTHRU : MOD_RES_DENY;
+	}
+
+	ModResult OnUserPreMessage(User* user, const MessageTarget& target, MessageDetails& details) CXX11_OVERRIDE
+	{
+		std::string ctcpname;
+		bool is_ctcp = details.IsCTCP(ctcpname) && !irc::equals(ctcpname, "ACTION");
+
+		SilenceEntry::SilenceFlags flag = SilenceEntry::SF_NONE;
+		if (target.type == MessageTarget::TYPE_CHANNEL)
+		{
+			if (is_ctcp)
+				flag = SilenceEntry::SF_CTCP_CHANNEL;
+			else if (details.type == MSG_NOTICE)
+				flag = SilenceEntry::SF_NOTICE_CHANNEL;
+			else if (details.type == MSG_PRIVMSG)
+				flag = SilenceEntry::SF_PRIVMSG_CHANNEL;
+
+			return BuildChannelExempts(user, target.Get<Channel>(), flag, details.exemptions);
+		}
+
+		if (target.type == MessageTarget::TYPE_USER)
+		{
+			if (is_ctcp)
+				flag = SilenceEntry::SF_CTCP_USER;
+			else if (details.type == MSG_NOTICE)
+				flag = SilenceEntry::SF_NOTICE_USER;
+			else if (details.type == MSG_PRIVMSG)
+				flag = SilenceEntry::SF_PRIVMSG_USER;
+
+			if (!CanReceiveMessage(user, target.Get<User>(), flag))
+			{
+				details.echo_original = true;
+				return MOD_RES_DENY;
+			}
+		}
+
+		return MOD_RES_PASSTHRU;
+	}
+
+	ModResult OnUserPreTagMessage(User* user, const MessageTarget& target, CTCTags::TagMessageDetails& details) CXX11_OVERRIDE
+	{
+		if (target.type == MessageTarget::TYPE_CHANNEL)
+			return BuildChannelExempts(user, target.Get<Channel>(), SilenceEntry::SF_TAGMSG_CHANNEL, details.exemptions);
+
+		if (target.type == MessageTarget::TYPE_USER && !CanReceiveMessage(user, target.Get<User>(), SilenceEntry::SF_TAGMSG_USER))
+		{
+			details.echo_original = true;
+			return MOD_RES_DENY;
+		}
+
+		return MOD_RES_PASSTHRU;
+	}
+
+	Version GetVersion() CXX11_OVERRIDE
+	{
+		return Version("Provides support for blocking users with the /SILENCE command", VF_OPTCOMMON | VF_VENDOR);
+	}
+};
+
+MODULE_INIT(ModuleSilence)