/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at https://mozilla.org/MPL/2.0/.
 *
 * (c) ZeroTier, Inc.
 * https://www.zerotier.com/
 */

#ifndef ZT_LINUX_NETLINK_HPP
#define ZT_LINUX_NETLINK_HPP

#include "../node/Constants.hpp"

#ifdef __LINUX__

#include <asm/types.h>
#include <linux/rtnetlink.h>
#include <map>
#include <set>
#include <sys/socket.h>
#include <vector>
// #include <linux/if.h>

#include "../node/Hashtable.hpp"
#include "../node/InetAddress.hpp"
#include "../node/MAC.hpp"
#include "../node/Mutex.hpp"
#include "Thread.hpp"

namespace ZeroTier {

/**
 * Interface with Linux's RTNETLINK
 */
class LinuxNetLink {
  private:
	LinuxNetLink();
	~LinuxNetLink();

  public:
	struct Route {
		InetAddress target;
		InetAddress via;
		InetAddress src;
		int ifidx;

		inline bool operator==(const Route& r) const
		{
			return ((target == r.target) && (via == r.via) && (src == r.src) && (ifidx == r.ifidx));
		}
		inline bool operator!=(const Route& r) const
		{
			return (! (*this == r));
		}
		inline bool operator<(const Route& r) const
		{
			if (target < r.target) {
				return true;
			}
			else if (target == r.target) {
				if (via < r.via) {
					return true;
				}
				else if (via == r.via) {
					if (src < r.src) {
						return true;
					}
					else if (src == r.src) {
						return (ifidx < r.ifidx);
					}
				}
			}
			return false;
		}
		inline bool operator>(const Route& r) const
		{
			return (r < *this);
		}
		inline bool operator<=(const Route& r) const
		{
			return ! (r < *this);
		}
		inline bool operator>=(const Route& r) const
		{
			return ! (*this < r);
		}
	};

	static LinuxNetLink& getInstance()
	{
		static LinuxNetLink instance;
		return instance;
	}

	LinuxNetLink(LinuxNetLink const&) = delete;
	void operator=(LinuxNetLink const&) = delete;

	void addRoute(const InetAddress& target, const InetAddress& via, const InetAddress& src, const char* ifaceName);
	void delRoute(const InetAddress& target, const InetAddress& via, const InetAddress& src, const char* ifaceName);

	void addAddress(const InetAddress& addr, const char* iface);
	void removeAddress(const InetAddress& addr, const char* iface);

	bool routeIsSet(const InetAddress& target, const InetAddress& via, const InetAddress& src, const char* ifname);

	void threadMain() throw();

  private:
	int _doRecv(int fd);

	void _processMessage(struct nlmsghdr* nlp, int nll);
	void _routeAdded(struct nlmsghdr* nlp);
	void _routeDeleted(struct nlmsghdr* nlp);
	void _linkAdded(struct nlmsghdr* nlp);
	void _linkDeleted(struct nlmsghdr* nlp);
	void _ipAddressAdded(struct nlmsghdr* nlp);
	void _ipAddressDeleted(struct nlmsghdr* nlp);

	void _requestInterfaceList();
	void _requestIPv4Routes();
	void _requestIPv6Routes();

	int _indexForInterface(const char* iface);

	void _setSocketTimeout(int fd, int seconds = 1);

	Thread _t;
	bool _running;

	uint32_t _seq;

	std::map<InetAddress, std::set<LinuxNetLink::Route> > _routes;
	Mutex _routes_m;

	struct iface_entry {
		iface_entry()
		{
			memset(this, 0, sizeof(iface_entry));
		}
		int index;
		char ifacename[16];	  // IFNAMSIZ on Linux == 16
		char mac[18];
		char mac_bin[6];
		unsigned int mtu;
	};
	Hashtable<int, iface_entry> _interfaces;
	Mutex _if_m;

	// socket communication vars;
	int _fd;
	struct sockaddr_nl _la;
};

}	// namespace ZeroTier

#endif

#endif	 // ZT_LINUX_NETLINK_HPPS