/*
 * validator/val_neg.c - validator aggressive negative caching functions.
 *
 * Copyright (c) 2007, NLnet Labs. All rights reserved.
 *
 * This software is open source.
 * 
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 
 * Redistributions of source code must retain the above copyright notice,
 * this list of conditions and the following disclaimer.
 * 
 * Redistributions in binary form must reproduce the above copyright notice,
 * this list of conditions and the following disclaimer in the documentation
 * and/or other materials provided with the distribution.
 * 
 * Neither the name of the NLNET LABS nor the names of its contributors may
 * be used to endorse or promote products derived from this software without
 * specific prior written permission.
 * 
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */

/**
 * \file
 *
 * This file contains helper functions for the validator module.
 * The functions help with aggressive negative caching.
 * This creates new denials of existance, and proofs for absence of types
 * from cached NSEC records.
 */
#include "config.h"
#include "validator/val_neg.h"
#include "util/log.h"
#include "util/data/dname.h"

int val_neg_compare(const void* a, const void* b)
{
	struct val_neg_data* x = (struct val_neg_data*)a;
	struct val_neg_data* y = (struct val_neg_data*)b;
	int m;
	if(x->dclass != y->dclass) {
		if(x->dclass < y->dclass)
			return -1;
		return 1;
	}
	return dname_canon_lab_cmp(x->name, x->labs, y->name, y->labs, &m);
}

struct val_neg_cache* val_neg_create()
{
	struct val_neg_cache* neg = (struct val_neg_cache*)calloc(1, 
		sizeof(*neg));
	if(!neg) {
		log_err("Could not create neg cache: out of memory");
		return NULL;
	}
	neg->max = 1024*1024; /* 1 M is about 5000(64bit)-10000(32) data */
	rbtree_init(&neg->tree, &val_neg_compare);
	lock_basic_init(&neg->lock);
	lock_protect(&neg->lock, neg, sizeof(*neg));
	return neg;
}

int val_neg_apply_cfg(struct val_neg_cache* neg, struct config_file* cfg)
{
	/* TODO read max mem size from cfg */
	return 1;
}

size_t val_neg_get_mem(struct val_neg_cache* neg)
{
	size_t result;
	lock_basic_lock(&neg->lock);
	result = sizeof(*neg) + neg->use;
	lock_basic_unlock(&neg->lock);
	return result;
}

void neg_cache_delete(struct val_neg_cache* neg)
{
	struct val_neg_data* p, *np;
	if(!neg) return;
	lock_basic_destroy(&neg->lock);
	/* delete all the elements */
	p = neg->first;
	while(p) {
		np = p->next;
		free(p->name);
		free(p);
		p = np;
	}
	free(neg);
}

void val_neg_addreply(struct val_neg_cache* neg, struct reply_info* rep)
{
	size_t i;
	for(i=rep->an_numrrsets; i< rep->an_numrrsets+rep->ns_numrrsets; i++){
		if(ntohs(rep->rrsets[i]->rk.type) != LDNS_RR_TYPE_NSEC)
			continue;
		/* insert the NSEC */
	}
}

int val_neg_dlvlookup(struct val_neg_cache* neg, uint8_t* qname, size_t len,
        uint16_t qclass)
{
	/* lookup closest data record */

	/* examine proof */

	/* delete closest data record if expired */

	/* if OK touch the LRU for it */
}