/*
	AddressManager.cpp
	
	IP Address Manager for Aladin
	Copyright (C) 2003 Mike Saywell
	
	Southampton Open Wireless Network,
	http://www.sown.org.uk

	~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~

	This class manages the IP addresses available for links.

	It takes a range of IPs (network address+netmask), splitting
	it into as many /30 subnets as possible.  These are allocated
	on demmand.

	~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~
	
	This program 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; either version 2
	of the License, or (at your option) any later version.

	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, write to the Free Software
	Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA. 

*/

#include "AddressManager.h"

AddressManager::AddressManager() {
	this->list = NULL;
	if(DEBUG) {
		cout << "New Allocation Manager" << endl;
	}
}

void AddressManager::setRange(struct in_addr* net, struct in_addr* mask) {
	this->netmask = mask;
	this->network = net;

	if(DEBUG) {
		cout << "Allocating addresses from " << inet_ntoa(*net);
		cout << "/" << inet_ntoa(*mask) << endl;
	}

	this->list = new struct AllocationList;	

	struct AllocationList* list = this->list;
	struct AddressAllocation* current = &(list->alloc);

	struct in_addr* link_mask = new struct in_addr;
	inet_aton("255.255.255.252", link_mask);

	// Create the first entry
	list->next = 0;
	current->allocated = false;
	memcpy(&(current->network), net, sizeof(struct in_addr));
	memcpy(&(current->netmask), link_mask, sizeof(struct in_addr));

	struct in_addr* net_inc = new struct in_addr;
	memcpy(net_inc, net, sizeof(struct in_addr));
	net_inc->s_addr = htonl(4+ntohl(net_inc->s_addr));
	
	if (DEBUG) {
		cout << "Allocation list:" << endl;
		cout << "Network: " << inet_ntoa(current->network) << endl;
	}

	while ((net_inc->s_addr & mask->s_addr) == (net->s_addr & mask->s_addr)) {
		// Add an item to the linked list
		list->next = new AllocationList();
		list = list->next;

		// Populate the item
		current = &(list->alloc);
		current->allocated = false;
		list->next = NULL;
		memcpy(&(current->network), net_inc, 4);
		memcpy(&(current->netmask), link_mask, 4);

		
		if (DEBUG) {
			cout << "Network: " << inet_ntoa(current->network) << endl;
		}
		net_inc->s_addr = htonl(4+ntohl(net_inc->s_addr));
	}
}

AddressAllocation* AddressManager::allocate() {
	struct AllocationList* current = this->list;

	while(current== NULL) {
		sleep(1);
	}

	while (current->alloc.allocated == true) {
		if(!current->next)
			return NULL;

		current = current ->next;
	}
	current->alloc.allocated = true;
	return &current->alloc;
}

void AddressManager::deallocate(AddressAllocation* alloc) {
	alloc->allocated = false;
}