/*
 * InspIRCd -- Internet Relay Chat Daemon
 *
 *   Copyright (C) 2019, 2022-2023 Sadie Powell <sadie@witchery.services>
 *   Copyright (C) 2014-2015 Attila Molnar <attilamolnar@hush.com>
 *   Copyright (C) 2012 Robby <robby@chatbelgie.be>
 *   Copyright (C) 2009-2010 Daniel De Graaf <danieldg@inspircd.org>
 *   Copyright (C) 2008 Robin Burchell <robin+git@viroteck.net>
 *   Copyright (C) 2008 Craig Edwards <brain@inspircd.org>
 *
 * 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"

/* Match CIDR strings, e.g. 127.0.0.1 to 127.0.0.0/8 or 3ffe:1:5:6::8 to 3ffe:1::0/32
 *
 * This will also attempt to match any leading usernames or nicknames on the mask, using
 * match(), when match_with_username is true.
 */
bool irc::sockets::MatchCIDR(const std::string& address, const std::string& cidr_mask, bool match_with_username)
{
	std::string address_copy;
	std::string cidr_copy;

	/* The caller is trying to match username@<mask>/bits.
	 * Chop off the username@ portion, use match() on it
	 * separately.
	 */
	if (match_with_username)
	{
		/* Use strchr not strrchr, because its going to be nearer to the left */
		std::string::size_type username_mask_pos = cidr_mask.rfind('@');
		std::string::size_type username_addr_pos = address.rfind('@');

		/* Both strings have an @ symbol in them */
		if (username_mask_pos != std::string::npos && username_addr_pos != std::string::npos)
		{
			/* Try and match() the strings before the @
			 * symbols, and recursively call MatchCIDR without
			 * username matching enabled to match the host part.
			 */
			return (InspIRCd::Match(address.substr(0, username_addr_pos), cidr_mask.substr(0, username_mask_pos), ascii_case_insensitive_map) &&
					MatchCIDR(address.substr(username_addr_pos + 1), cidr_mask.substr(username_mask_pos + 1), false));
		}
		else
		{
			address_copy.assign(address, username_addr_pos + 1, std::string::npos);
			cidr_copy.assign(cidr_mask, username_mask_pos + 1, std::string::npos);
		}
	}
	else
	{
		address_copy.assign(address);
		cidr_copy.assign(cidr_mask);
	}

	const std::string::size_type per_pos = cidr_copy.rfind('/');
	if ((per_pos != std::string::npos) && ((per_pos == cidr_copy.length()-1)
		|| (cidr_copy.find_first_not_of("0123456789", per_pos+1) != std::string::npos)
		|| (cidr_copy.find_first_not_of("0123456789abcdefABCDEF.:") < per_pos)))
	{
		// The CIDR mask is invalid
		return false;
	}

	irc::sockets::sockaddrs addr(false);
	if (!addr.from_ip(address_copy))
	{
		// The address could not be parsed.
		return false;
	}

	irc::sockets::cidr_mask mask(cidr_copy);
	irc::sockets::cidr_mask mask2(addr, mask.length);

	return mask == mask2;
}
