/*
* validator/val_neg.h - validator aggressive negative caching functions.
*
* Copyright (c) 2008, 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 COPYRIGHT
* HOLDER 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 existence, and proofs for absence of types
* from cached NSEC records.
*/
#ifndef VALIDATOR_VAL_NEG_H
#define VALIDATOR_VAL_NEG_H
#include "util/locks.h"
#include "util/rbtree.h"
struct sldns_buffer;
struct val_neg_data;
struct config_file;
struct reply_info;
struct rrset_cache;
struct regional;
struct query_info;
struct dns_msg;
struct ub_packed_rrset_key;
/**
* The negative cache. It is shared between the threads, so locked.
* Kept as validator-environ-state. It refers back to the rrset cache for
* data elements. It can be out of date and contain conflicting data
* from zone content changes.
* It contains a tree of zones, every zone has a tree of data elements.
* The data elements are part of one big LRU list, with one memory counter.
*/
struct val_neg_cache {
/** the big lock on the negative cache. Because we use a rbtree
* for the data (quick lookup), we need a big lock */
lock_basic_t lock;
/** The zone rbtree. contents sorted canonical, type val_neg_zone */
rbtree_t tree;
/** the first in linked list of LRU of val_neg_data */
struct val_neg_data* first;
/** last in lru (least recently used element) */
struct val_neg_data* last;
/** current memory in use (bytes) */
size_t use;
/** max memory to use (bytes) */
size_t max;
/** max nsec3 iterations allowed */
size_t nsec3_max_iter;
};
/**
* Per Zone aggressive negative caching data.
*/
struct val_neg_zone {
/** rbtree node element, key is this struct: the name, class */
rbnode_t node;
/** name; the key */
uint8_t* name;
/** length of name */
size_t len;
/** labels in name */
int labs;
/** pointer to parent zone in the negative cache */
struct val_neg_zone* parent;
/** the number of elements, including this one and the ones whose
* parents (-parents) include this one, that are in_use
* No elements have a count of zero, those are removed. */
int count;
/** if 0: NSEC zone, else NSEC3 hash algorithm in use */
int nsec3_hash;
/** nsec3 iteration count in use */
size_t nsec3_iter;
/** nsec3 salt in use */
uint8_t* nsec3_salt;
/** length of salt in bytes */
size_t nsec3_saltlen;
/** tree of NSEC data for this zone, sorted canonical
* by NSEC owner name */
rbtree_t tree;
/** class of node; host order */
uint16_t dclass;
/** if this element is in use, boolean */
uint8_t in_use;
};
/**
* Data element for aggressive negative caching.
* The tree of these elements acts as an index onto the rrset cache.
* It shows the NSEC records that (may) exist and are (possibly) secure.
* The rbtree allows for logN search for a covering NSEC record.
* To make tree insertion and deletion logN too, all the parent (one label
* less than the name) data elements are also in the rbtree, with a usage
* count for every data element.
* There is no actual data stored in this data element, if it is in_use,
* then the data can (possibly) be found in the rrset cache.
*/
struct val_neg_data {
/** rbtree node element, key is this struct: the name */
rbnode_t node;
/** name; the key */
uint8_t* name;
/** length of name */
size_t len;
/** labels in name */
int labs;
/** pointer to parent node in the negative cache */
struct val_neg_data* parent;
/** the number of elements, including this one and the ones whose
* parents (-parents) include this one, that are in use
* No elements have a count of zero, those are removed. */
int count;
/** the zone that this denial is part of */
struct val_neg_zone* zone;
/** previous in LRU */
struct val_neg_data* prev;
/** next in LRU (next element was less recently used) */
struct val_neg_data* next;
/** if this element is in use, boolean */
uint8_t in_use;
};
/**
* Create negative cache
* @param cfg: config options.
* @param maxiter: max nsec3 iterations allowed.
* @return neg cache, empty or NULL on failure.
*/
struct val_neg_cache* val_neg_create(struct config_file* cfg, size_t maxiter);
/**
* see how much memory is in use by the negative cache.
* @param neg: negative cache
* @return number of bytes in use.
*/
size_t val_neg_get_mem(struct val_neg_cache* neg);
/**
* Destroy negative cache. There must no longer be any other threads.
* @param neg: negative cache.
*/
void neg_cache_delete(struct val_neg_cache* neg);
/**
* Comparison function for rbtree val neg data elements
*/
int val_neg_data_compare(const void* a, const void* b);
/**
* Comparison function for rbtree val neg zone elements
*/
int val_neg_zone_compare(const void* a, const void* b);
/**
* Insert NSECs from this message into the negative cache for reference.
* @param neg: negative cache
* @param rep: reply with NSECs.
* Errors are ignored, means that storage is omitted.
*/
void val_neg_addreply(struct val_neg_cache* neg, struct reply_info* rep);
/**
* Insert NSECs from this referral into the negative cache for reference.
* @param neg: negative cache
* @param rep: referral reply with NS, NSECs.
* @param zone: bailiwick for the referral.
* Errors are ignored, means that storage is omitted.
*/
void val_neg_addreferral(struct val_neg_cache* neg, struct reply_info* rep,
uint8_t* zone);
/**
* Perform a DLV style lookup
* During the lookup, we could find out that data has expired. In that
* case the neg_cache entries are removed, and lookup fails.
*
* @param neg: negative cache.
* @param qname: name to look for
* @param len: length of qname.
* @param qclass: class to look in.
* @param rrset_cache: the rrset cache, for NSEC lookups.
* @param now: current time for ttl checks.
* @return
* 0 on error
* 0 if no proof of negative
* 1 if indeed negative was proven
* thus, qname DLV qclass does not exist.
*/
int val_neg_dlvlookup(struct val_neg_cache* neg, uint8_t* qname, size_t len,
uint16_t qclass, struct rrset_cache* rrset_cache, time_t now);
/**
* For the given query, try to get a reply out of the negative cache.
* The reply still needs to be validated.
* @param neg: negative cache.
* @param qinfo: query
* @param region: where to allocate reply.
* @param rrset_cache: rrset cache.
* @param buf: temporary buffer.
* @param now: to check TTLs against.
* @param addsoa: if true, produce result for external consumption.
* if false, do not add SOA - for unbound-internal consumption.
* @param topname: do not look higher than this name,
* so that the result cannot be taken from a zone above the current
* trust anchor. Which could happen with multiple islands of trust.
* if NULL, then no trust anchor is used, but also the algorithm becomes
* more conservative, especially for opt-out zones, since the receiver
* may have a trust-anchor below the optout and thus the optout cannot
* be used to create a proof from the negative cache.
* @return a reply message if something was found.
* This reply may still need validation.
* NULL if nothing found (or out of memory).
*/
struct dns_msg* val_neg_getmsg(struct val_neg_cache* neg,
struct query_info* qinfo, struct regional* region,
struct rrset_cache* rrset_cache, struct sldns_buffer* buf, time_t now,
int addsoa, uint8_t* topname);
/**** functions exposed for unit test ****/
/**
* Insert data into the data tree of a zone
* Does not do locking.
* @param neg: negative cache
* @param zone: zone to insert into
* @param nsec: record to insert.
*/
void neg_insert_data(struct val_neg_cache* neg,
struct val_neg_zone* zone, struct ub_packed_rrset_key* nsec);
/**
* Delete a data element from the negative cache.
* May delete other data elements to keep tree coherent, or
* only mark the element as 'not in use'.
* Does not do locking.
* @param neg: negative cache.
* @param el: data element to delete.
*/
void neg_delete_data(struct val_neg_cache* neg, struct val_neg_data* el);
/**
* Find the given zone, from the SOA owner name and class
* Does not do locking.
* @param neg: negative cache
* @param nm: what to look for.
* @param len: length of nm
* @param dclass: class to look for.
* @return zone or NULL if not found.
*/
struct val_neg_zone* neg_find_zone(struct val_neg_cache* neg,
uint8_t* nm, size_t len, uint16_t dclass);
/**
* Create a new zone.
* Does not do locking.
* @param neg: negative cache
* @param nm: what to look for.
* @param nm_len: length of name.
* @param dclass: class of zone, host order.
* @return zone or NULL if out of memory.
*/
struct val_neg_zone* neg_create_zone(struct val_neg_cache* neg,
uint8_t* nm, size_t nm_len, uint16_t dclass);
/**
* take a zone into use. increases counts of parents.
* Does not do locking.
* @param zone: zone to take into use.
*/
void val_neg_zone_take_inuse(struct val_neg_zone* zone);
#endif /* VALIDATOR_VAL_NEG_H */
