/*
 * \brief  DHCP server role of a domain
 * \author Martin Stein
 * \date   2016-08-19
 */

/*
 * Copyright (C) 2016-2017 Genode Labs GmbH
 *
 * This file is part of the Genode OS framework, which is distributed
 * under the terms of the GNU Affero General Public License version 3.
 */

/* local includes */
#include <dhcp_server.h>
#include <interface.h>
#include <domain.h>
#include <configuration.h>

using namespace Net;
using namespace Genode;


/*****************
 ** Dhcp_server **
 *****************/

void Dhcp_server::_invalid(Domain     &domain,
                           char const *reason)
{
	if (domain.config().verbose()) {
		log("[", domain, "] invalid DHCP server (", reason, ")"); }

	throw Domain::Invalid();
}


Dhcp_server::Dhcp_server(Xml_node            const  node,
                         Domain                    &domain,
                         Allocator                 &alloc,
                         Ipv4_address_prefix const &interface,
                         Domain_tree               &domains)
:
	_dns_server(node.attribute_value("dns_server", Ipv4_address())),
	_dns_server_from(_init_dns_server_from(node, domains)),
	_ip_lease_time  (_init_ip_lease_time(node)),
	_ip_first(node.attribute_value("ip_first", Ipv4_address())),
	_ip_last(node.attribute_value("ip_last", Ipv4_address())),
	_ip_first_raw(_ip_first.to_uint32_little_endian()),
	_ip_count(_ip_last.to_uint32_little_endian() - _ip_first_raw + 1),
	_ip_alloc(alloc, _ip_count)
{
	if (!interface.prefix_matches(_ip_first)) {
		_invalid(domain, "first IP does not match domain subnet"); }

	if (!interface.prefix_matches(_ip_last)) {
		_invalid(domain, "last IP does not match domain subnet"); }

	if (interface.address.is_in_range(_ip_first, _ip_last)) {
		_invalid(domain, "IP range contains IP address of domain"); }
}


Microseconds Dhcp_server::_init_ip_lease_time(Xml_node const node)
{
	uint64_t ip_lease_time_sec =
		node.attribute_value("ip_lease_time_sec", (uint64_t)0);

	if (!ip_lease_time_sec) {
		ip_lease_time_sec = DEFAULT_IP_LEASE_TIME_SEC;
	}
	return Microseconds((uint64_t)ip_lease_time_sec * 1000 * 1000);
}


void Dhcp_server::print(Output &output) const
{
	if (_dns_server.valid()) {
		Genode::print(output, "DNS server ", _dns_server, ", ");
	}
	try { Genode::print(output, "DNS server from ", _dns_server_from(), ", "); }
	catch (Pointer<Domain>::Invalid) { }

	Genode::print(output, "IP first ", _ip_first,
	                        ", last ", _ip_last,
	                       ", count ", _ip_count,
	                  ", lease time ", _ip_lease_time.value / 1000 / 1000, " sec");
}


Ipv4_address Dhcp_server::alloc_ip()
{
	try {
		return Ipv4_address::from_uint32_little_endian(_ip_alloc.alloc() +
		                                               _ip_first_raw);
	}
	catch (Bit_allocator_dynamic::Out_of_indices) {
		throw Alloc_ip_failed();
	}
}


void Dhcp_server::alloc_ip(Ipv4_address const &ip)
{
	try { _ip_alloc.alloc_addr(ip.to_uint32_little_endian() - _ip_first_raw); }
	catch (Bit_allocator_dynamic::Range_conflict)   { throw Alloc_ip_failed(); }
	catch (Bit_array_dynamic::Invalid_index_access) { throw Alloc_ip_failed(); }
}


void Dhcp_server::free_ip(Ipv4_address const &ip)
{
	_ip_alloc.free(ip.to_uint32_little_endian() - _ip_first_raw);
}


Pointer<Domain> Dhcp_server::_init_dns_server_from(Genode::Xml_node const  node,
                                                   Domain_tree            &domains)
{
	if (_dns_server.valid()) {
		return Pointer<Domain>();
	}
	Domain_name dns_server_from =
		node.attribute_value("dns_server_from", Domain_name());

	if (dns_server_from == Domain_name()) {
		return Pointer<Domain>();
	}
	try { return domains.find_by_name(dns_server_from); }
	catch (Domain_tree::No_match) { throw Invalid(); }
}


Ipv4_address const &Dhcp_server::dns_server() const
{
	try { return _dns_server_from().ip_config().dns_server; }
	catch (Pointer<Domain>::Invalid) { }
	return _dns_server;
}


bool Dhcp_server::ready() const
{
	if (_dns_server.valid()) {
		return true;
	}
	try { return _dns_server_from().ip_config().valid; }
	catch (Pointer<Domain>::Invalid) { }
	return true;
}


/*********************
 ** Dhcp_allocation **
 *********************/

Dhcp_allocation::Dhcp_allocation(Interface      &interface,
                             Ipv4_address const &ip,
                             Mac_address  const &mac,
                             Timer::Connection  &timer,
                             Microseconds        lifetime)
:
	_interface(interface), _ip(ip), _mac(mac),
	_timeout(timer, *this, &Dhcp_allocation::_handle_timeout)
{
	_interface.dhcp_stats().alive++;
	_timeout.schedule(lifetime);
}


Dhcp_allocation::~Dhcp_allocation()
{
	_interface.dhcp_stats().alive--;
	_interface.dhcp_stats().destroyed++;
}


void Dhcp_allocation::lifetime(Microseconds lifetime)
{
	_timeout.schedule(lifetime);
}


bool Dhcp_allocation::_higher(Mac_address const &mac) const
{
	return memcmp(mac.addr, _mac.addr, sizeof(_mac.addr)) > 0;
}


Dhcp_allocation &Dhcp_allocation::find_by_mac(Mac_address const &mac)
{
	if (mac == _mac) {
		return *this; }

	Dhcp_allocation *const allocation = child(_higher(mac));
	if (!allocation) {
		throw Dhcp_allocation_tree::No_match(); }

	return allocation->find_by_mac(mac);
}


void Dhcp_allocation::print(Output &output) const
{
	Genode::print(output, "MAC ", _mac, " IP ", _ip);
}


void Dhcp_allocation::_handle_timeout(Duration)
{
	_interface.dhcp_allocation_expired(*this);
}


/**************************
 ** Dhcp_allocation_tree **
 **************************/

Dhcp_allocation &
Dhcp_allocation_tree::find_by_mac(Mac_address const &mac) const
{
	if (!_tree.first()) {
		throw No_match(); }

	return _tree.first()->find_by_mac(mac);
}