/*
 * util/data/packed_rrset.h - data storage for a set of resource records.
 *
 * 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 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 the data storage for RRsets.
 */

#ifndef UTIL_DATA_PACKED_RRSET_H
#define UTIL_DATA_PACKED_RRSET_H
#include "util/storage/lruhash.h"
struct alloc_cache;
struct regional;

/** type used to uniquely identify rrsets. Cannot be reused without
 * clearing the cache. */
typedef uint64_t rrset_id_type;

/** this rrset is NSEC and is at zone apex (at child side of zonecut) */
#define PACKED_RRSET_NSEC_AT_APEX 0x1
/** this rrset is A/AAAA and is in-zone-glue (from parent side of zonecut) */
#define PACKED_RRSET_PARENT_SIDE 0x2
/** this rrset is SOA and has the negative ttl (from nxdomain or nodata),
 * this is set on SOA rrsets in the authority section, to keep its TTL separate
 * from the SOA in the answer section from a direct SOA query or ANY query. */
#define PACKED_RRSET_SOA_NEG 0x4
/** This rrset is considered to have a fixed TTL; its TTL doesn't have to be
 * updated on encoding in a reply.  This flag is not expected to be set in
 * cached data. */
#define PACKED_RRSET_FIXEDTTL 0x80000000

/** number of rrs and rrsets for integer overflow protection.  More than
 * this is not really possible (64K packet has much less RRs and RRsets) in
 * a message.  And this is small enough that also multiplied there is no
 * integer overflow. */
#define RR_COUNT_MAX 0xffffff

/**
 * The identifying information for an RRset.
 */
struct packed_rrset_key {
	/**
	 * The domain name. If not null (for id=0) it is allocated, and
	 * contains the wireformat domain name.
	 * This dname is not canonicalized.
	 */
	uint8_t* dname;
	/** 
	 * Length of the domain name, including last 0 root octet. 
	 */
	size_t dname_len;
	/**
	 * Flags. 32bit to be easy for hashing:
	 * 	o PACKED_RRSET_NSEC_AT_APEX
	 * 	o PACKED_RRSET_PARENT_SIDE
	 * 	o PACKED_RRSET_SOA_NEG
	 * 	o PACKED_RRSET_FIXEDTTL (not supposed to be cached)
	 */
	uint32_t flags;
	/** the rrset type in network format */
	uint16_t type;
	/** the rrset class in network format */
	uint16_t rrset_class;
};

/**
 * This structure contains an RRset. A set of resource records that
 * share the same domain name, type and class.
 *
 * Due to memory management and threading, the key structure cannot be
 * deleted, although the data can be. The id can be set to 0 to store and the
 * structure can be recycled with a new id.
 */
struct ub_packed_rrset_key {
	/** 
	 * entry into hashtable. Note the lock is never destroyed,
	 *  even when this key is retired to the cache. 
	 * the data pointer (if not null) points to a struct packed_rrset.
	 */
	struct lruhash_entry entry;
	/** 
	 * the ID of this rrset. unique, based on threadid + sequenceno. 
	 * ids are not reused, except after flushing the cache.
	 * zero is an unused entry, and never a valid id.
	 * Check this value after getting entry.lock.
	 * The other values in this struct may only be altered after changing
	 * the id (which needs a writelock on entry.lock).
	 */
	rrset_id_type id;
	/** key data: dname, type and class */
	struct packed_rrset_key rk;
};

/**
 * RRset trustworthiness. Bigger value is more trust. RFC 2181.
 * The rrset_trust_add_noAA, rrset_trust_auth_noAA, rrset_trust_add_AA,
 * are mentioned as the same trustworthiness in 2181, but split up here
 * for ease of processing.
 *
 * rrset_trust_nonauth_ans_AA, rrset_trust_ans_noAA
 * are also mentioned as the same trustworthiness in 2181, but split up here
 * for ease of processing.
 *
 * Added trust_none for a sane initial value, smaller than anything else.
 * Added validated and ultimate trust for keys and rrsig validated content.
 */
enum rrset_trust {
	/** initial value for trust */
	rrset_trust_none = 0,
	/** Additional information from non-authoritative answers */
	rrset_trust_add_noAA,
	/** Data from the authority section of a non-authoritative answer */
	rrset_trust_auth_noAA,
	/** Additional information from an authoritative answer */
	rrset_trust_add_AA,
	/** non-authoritative data from the answer section of authoritative
	 * answers */
	rrset_trust_nonauth_ans_AA,
	/** Data from the answer section of a non-authoritative answer */
	rrset_trust_ans_noAA,
	/** Glue from a primary zone, or glue from a zone transfer */
	rrset_trust_glue,
	/** Data from the authority section of an authoritative answer */
	rrset_trust_auth_AA,
	/** The authoritative data included in the answer section of an
	 *  authoritative reply */
	rrset_trust_ans_AA,
	/** Data from a zone transfer, other than glue */
	rrset_trust_sec_noglue,
	/** Data from a primary zone file, other than glue data */
	rrset_trust_prim_noglue,
	/** DNSSEC(rfc4034) validated with trusted keys */
	rrset_trust_validated,
	/** ultimately trusted, no more trust is possible; 
	 * trusted keys from the unbound configuration setup. */
	rrset_trust_ultimate
};

/**
 * Security status from validation for data.
 * The order is significant; more secure, more proven later.
 */
enum sec_status {
	/** UNCHECKED means that object has yet to be validated. */
	sec_status_unchecked = 0,
	/** BOGUS means that the object (RRset or message) failed to validate
	 *  (according to local policy), but should have validated. */
	sec_status_bogus,
	/** INDETERMINATE means that the object is insecure, but not 
	 * authoritatively so. Generally this means that the RRset is not 
	 * below a configured trust anchor. */
	sec_status_indeterminate,
	/** INSECURE means that the object is authoritatively known to be 
	 * insecure. Generally this means that this RRset is below a trust 
	 * anchor, but also below a verified, insecure delegation. */
	sec_status_insecure,
	/** SECURE means that the object (RRset or message) validated 
	 * according to local policy. */
	sec_status_secure
};

/**
 * RRset data.
 *
 * The data is packed, stored contiguously in memory.
 *
 * It is not always stored contiguously, in that case, an unpacked-packed
 * rrset has the arrays separate.  A bunch of routines work on that, but
 * the packed rrset that is contiguous is for the rrset-cache and the
 * cache-response routines in daemon/worker.c.
 *
 * memory layout:
 *	o base struct
 *	o rr_len size_t array
 *	o rr_data uint8_t* array
 *	o rr_ttl time_t array (after size_t and ptrs because those may be
 *		64bit and this array before those would make them unaligned).
 *		Since the stuff before is 32/64bit, rr_ttl is 32 bit aligned.
 *	o rr_data rdata wireformats
 *	o rrsig_data rdata wireformat(s)
 *
 * Rdata is stored in wireformat. The dname is stored in wireformat.
 * TTLs are stored as absolute values (and could be expired).
 *
 * RRSIGs are stored in the arrays after the regular rrs.
 *
 * You need the packed_rrset_key to know dname, type, class of the
 * resource records in this RRset. (if signed the rrsig gives the type too).
 *
 * On the wire an RR is:
 *	name, type, class, ttl, rdlength, rdata.
 * So we need to send the following per RR:
 *	key.dname, ttl, rr_data[i].
 *	since key.dname ends with type and class.
 *	and rr_data starts with the rdlength.
 *	the ttl value to send changes due to time.
 */
struct packed_rrset_data {
	/** TTL (in seconds like time()) of the rrset.
	 * Same for all RRs see rfc2181(5.2).  */
	time_t ttl;
	/** number of rrs. */
	size_t count;
	/** number of rrsigs, if 0 no rrsigs */
	size_t rrsig_count;
	/** the trustworthiness of the rrset data */
	enum rrset_trust trust; 
	/** security status of the rrset data */
	enum sec_status security;
	/** length of every rr's rdata, rr_len[i] is size of rr_data[i]. */
	size_t* rr_len;
	/** ttl of every rr. rr_ttl[i] ttl of rr i. */
	time_t *rr_ttl;
	/** 
	 * Array of pointers to every rr's rdata. 
	 * The rr_data[i] rdata is stored in uncompressed wireformat. 
	 * The first uint16_t of rr_data[i] is network format rdlength.
	 *
	 * rr_data[count] to rr_data[count+rrsig_count] contain the rrsig data.
	 */
	uint8_t** rr_data;
};

/**
 * An RRset can be represented using both key and data together.
 * Split into key and data structures to simplify implementation of
 * caching schemes.
 */
struct packed_rrset {
	/** domain name, type and class */
	struct packed_rrset_key* k;
	/** ttl, count and rdatas (and rrsig) */
	struct packed_rrset_data* d;
};

/**
 * list of packed rrsets
 */
struct packed_rrset_list {
	/** next in list */
	struct packed_rrset_list* next;
	/** rrset key and data */
	struct packed_rrset rrset;
};

/**
 * Delete packed rrset key and data, not entered in hashtables yet.
 * Used during parsing.
 * @param pkey: rrset key structure with locks, key and data pointers.
 * @param alloc: where to return the unfree-able key structure.
 */
void ub_packed_rrset_parsedelete(struct ub_packed_rrset_key* pkey,
	struct alloc_cache* alloc);

/**
 * Memory size of rrset data. RRset data must be filled in correctly.
 * @param data: data to examine.
 * @return size in bytes.
 */
size_t packed_rrset_sizeof(struct packed_rrset_data* data);

/**
 * Get TTL of rrset. RRset data must be filled in correctly.
 * @param key: rrset key, with data to examine.
 * @return ttl value.
 */
time_t ub_packed_rrset_ttl(struct ub_packed_rrset_key* key);

/**
 * Calculate memory size of rrset entry. For hash table usage.
 * @param key: struct ub_packed_rrset_key*.
 * @param data: struct packed_rrset_data*.
 * @return size in bytes.
 */
size_t ub_rrset_sizefunc(void* key, void* data);

/**
 * compares two rrset keys.
 * @param k1: struct ub_packed_rrset_key*.
 * @param k2: struct ub_packed_rrset_key*.
 * @return 0 if equal.
 */
int ub_rrset_compare(void* k1, void* k2);

/**
 * compare two rrset data structures.
 * Compared rdata and rrsigdata, not the trust or ttl value.
 * @param d1: data to compare.
 * @param d2: data to compare.
 * @return 1 if equal.
 */
int rrsetdata_equal(struct packed_rrset_data* d1, struct packed_rrset_data* d2);

/**
 * Old key to be deleted. RRset keys are recycled via alloc.
 * The id is set to 0. So that other threads, after acquiring a lock always
 * get the correct value, in this case the 0 deleted-special value.
 * @param key: struct ub_packed_rrset_key*.
 * @param userdata: alloc structure to use for recycling.
 */
void ub_rrset_key_delete(void* key, void* userdata);

/**
 * Old data to be deleted.
 * @param data: what to delete.
 * @param userdata: user data ptr.
 */
void rrset_data_delete(void* data, void* userdata);

/**
 * Calculate hash value for a packed rrset key.
 * @param key: the rrset key with name, type, class, flags.
 * @return hash value.
 */
hashvalue_type rrset_key_hash(struct packed_rrset_key* key);

/**
 * Fixup pointers in fixed data packed_rrset_data blob.
 * After a memcpy of the data for example. Will set internal pointers right.
 * @param data: rrset data structure. Otherwise correctly filled in.
 */
void packed_rrset_ptr_fixup(struct packed_rrset_data* data);

/**
 * Fixup TTLs in fixed data packed_rrset_data blob.
 * @param data: rrset data structure. Otherwise correctly filled in.
 * @param add: how many seconds to add, pass time(0) for example.
 */
void packed_rrset_ttl_add(struct packed_rrset_data* data, time_t add);

/**
 * Utility procedure to extract CNAME target name from its rdata.
 * Failsafes; it will change passed dname to a valid dname or do nothing.
 * @param rrset: the rrset structure. Must be a CNAME. 
 *	Only first RR is used (multiple RRs are technically illegal anyway).
 * 	Also works on type DNAME. Returns target name.
 * @param dname: this pointer is updated to point into the cname rdata.
 *	If a failsafe fails, nothing happens to the pointer (such as the
 *	rdata was not a valid dname, not a CNAME, ...).
 * @param dname_len: length of dname is returned.
 */
void get_cname_target(struct ub_packed_rrset_key* rrset, uint8_t** dname, 
	size_t* dname_len);

/**
 * Get a printable string for a rrset trust value 
 * @param s: rrset trust value
 * @return printable string.
 */
const char* rrset_trust_to_string(enum rrset_trust s);

/**
 * Get a printable string for a security status value 
 * @param s: security status
 * @return printable string.
 */
const char* sec_status_to_string(enum sec_status s);

/**
 * Print string with neat domain name, type, class from rrset.
 * @param v: at what verbosity level to print this.
 * @param str: string of message.
 * @param rrset: structure with name, type and class.
 */
void log_rrset_key(enum verbosity_value v, const char* str, 
	struct ub_packed_rrset_key* rrset);

/**
 * Convert RR from RRset to string.
 * @param rrset: structure with data.
 * @param i: index of rr or RRSIG.
 * @param now: time that is subtracted from ttl before printout. Can be 0.
 * @param dest: destination string buffer. Must be nonNULL.
 * @param dest_len: length of dest buffer (>0).
 * @return false on failure.
 */
int packed_rr_to_string(struct ub_packed_rrset_key* rrset, size_t i,
	time_t now, char* dest, size_t dest_len);

/**
 * Print the string with prefix, one rr per line.
 * @param v: at what verbosity level to print this.
 * @param str: string of message.
 * @param rrset: with name, and rdata, and rrsigs.
 */
void log_packed_rrset(enum verbosity_value v, const char* str,
	struct ub_packed_rrset_key* rrset);

/** 
 * Allocate rrset in region - no more locks needed 
 * @param key: a (just from rrset cache looked up) rrset key + valid,
 * 	packed data record.
 * @param region: where to alloc the copy
 * @param now: adjust the TTLs to be relative (subtract from all TTLs).
 * @return new region-alloced rrset key or NULL on alloc failure.
 */
struct ub_packed_rrset_key* packed_rrset_copy_region(
	struct ub_packed_rrset_key* key, struct regional* region, 
	time_t now);

/** 
 * Allocate rrset with malloc (from region or you are holding the lock).
 * @param key: key with data entry.
 * @param alloc: alloc_cache to create rrset_keys
 * @param now: adjust the TTLs to be absolute (add to all TTLs).
 * @return new region-alloced rrset key or NULL on alloc failure.
 */
struct ub_packed_rrset_key* packed_rrset_copy_alloc(
	struct ub_packed_rrset_key* key, struct alloc_cache* alloc, 
	time_t now);

#endif /* UTIL_DATA_PACKED_RRSET_H */
