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/* Copyright (C) 2014-2017 CZ.NIC, z.s.p.o. <knot-dns@labs.nic.cz>
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 3 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, see <https://www.gnu.org/licenses/>.
*/
#pragma once
#include <netinet/in.h>
#include <sys/socket.h>
#include <libknot/dname.h>
#include <limits.h>
#include "lib/defines.h"
#include "lib/generic/lru.h"
struct kr_query;
/**
* NS RTT score (special values).
* @note RTT is measured in milliseconds.
*/
enum kr_ns_score {
KR_NS_MAX_SCORE = 20 * KR_CONN_RTT_MAX, /* max possible value */
KR_NS_FWD_TIMEOUT = (95 * 10000) / 100, /* timeout for upstream recursor,
* 95 percents from max resolution time */
KR_NS_TIMEOUT = (95 * KR_CONN_RTT_MAX) / 100, /* timeout for upstream auth */
KR_NS_LONG = (3 * KR_NS_TIMEOUT) / 4,
KR_NS_UNKNOWN = KR_NS_TIMEOUT / 2,
KR_NS_PENALTY = 100,
KR_NS_GLUED = 10
};
/**
* See kr_nsrep_update_rtt()
*/
#define KR_NS_DEAD (((KR_NS_TIMEOUT * 4) + 3) / 3)
#define KR_NS_FWD_DEAD (((KR_NS_FWD_TIMEOUT * 4) + 3) / 3)
/** If once NS was marked as "timeouted", it won't participate in NS elections
* at least KR_NS_TIMEOUT_RETRY_INTERVAL milliseconds (now: one second). */
#define KR_NS_TIMEOUT_RETRY_INTERVAL 1000
/**
* NS QoS flags.
*/
enum kr_ns_rep {
KR_NS_NOIP4 = 1 << 0, /**< NS has no IPv4 */
KR_NS_NOIP6 = 1 << 1, /**< NS has no IPv6 */
KR_NS_NOEDNS = 1 << 2 /**< NS has no EDNS support */
};
/**
* NS RTT update modes.
* First update is always KR_NS_RESET unless
* KR_NS_UPDATE_NORESET mode had choosen.
*/
enum kr_ns_update_mode {
KR_NS_UPDATE = 0, /**< Update as smooth over last two measurements */
KR_NS_UPDATE_NORESET, /**< Same as KR_NS_UPDATE, but disable fallback to
* KR_NS_RESET on newly added entries.
* Zero is used as initial value. */
KR_NS_RESET, /**< Set to given value */
KR_NS_ADD, /**< Increment current value */
KR_NS_MAX /**< Set to maximum of current/proposed value. */
};
struct kr_nsrep_rtt_lru_entry {
unsigned score; /* combined rtt */
uint64_t tout_timestamp; /* The time when score became
* greater or equal then KR_NS_TIMEOUT.
* Is meaningful only when score >= KR_NS_TIMEOUT */
};
typedef struct kr_nsrep_rtt_lru_entry kr_nsrep_rtt_lru_entry_t;
/**
* NS QoS tracking.
*/
typedef lru_t(kr_nsrep_rtt_lru_entry_t) kr_nsrep_rtt_lru_t;
/**
* NS reputation tracking.
*/
typedef lru_t(unsigned) kr_nsrep_lru_t;
/* Maximum count of addresses probed in one go (last is left empty) */
#define KR_NSREP_MAXADDR 4
/**
* Name server representation.
* Contains extra information about the name server, e.g. score
* or other metadata.
*/
struct kr_nsrep
{
unsigned score; /**< NS score */
unsigned reputation; /**< NS reputation */
const knot_dname_t *name; /**< NS name */
struct kr_context *ctx; /**< Resolution context */
union inaddr addr[KR_NSREP_MAXADDR]; /**< NS address(es) */
};
/**
* Set given NS address. (Very low-level access to the list.)
* @param qry updated query
* @param index index of the updated target
* @param sock socket address to use (sockaddr_in or sockaddr_in6 or NULL)
* @return 0 or an error code, in particular kr_error(ENOENT) for net.ipvX
*/
KR_EXPORT
int kr_nsrep_set(struct kr_query *qry, size_t index, const struct sockaddr *sock);
/**
* Elect best nameserver/address pair from the nsset.
* @param qry updated query
* @param ctx resolution context
* @return 0 or an error code
*/
KR_EXPORT
int kr_nsrep_elect(struct kr_query *qry, struct kr_context *ctx);
/**
* Elect best nameserver/address pair from the nsset.
* @param qry updated query
* @param ctx resolution context
* @return 0 or an error code
*/
KR_EXPORT
int kr_nsrep_elect_addr(struct kr_query *qry, struct kr_context *ctx);
/**
* Update NS address RTT information.
*
* @brief In KR_NS_UPDATE mode reputation is smoothed over last N measurements.
*
* @param ns updated NS representation
* @param addr chosen address (NULL for first)
* @param score new score (i.e. RTT), see enum kr_ns_score
* @param cache RTT LRU cache
* @param umode update mode (KR_NS_UPDATE or KR_NS_RESET or KR_NS_ADD)
* @return 0 on success, error code on failure
*/
KR_EXPORT
int kr_nsrep_update_rtt(struct kr_nsrep *ns, const struct sockaddr *addr,
unsigned score, kr_nsrep_rtt_lru_t *cache, int umode);
/**
* Update NSSET reputation information.
*
* @param ns updated NS representation
* @param reputation combined reputation flags, see enum kr_ns_rep
* @param cache LRU cache
* @return 0 on success, error code on failure
*/
KR_EXPORT
int kr_nsrep_update_rep(struct kr_nsrep *ns, unsigned reputation, kr_nsrep_lru_t *cache);
/**
* Copy NSSET reputation information and resets score.
*
* @param dst updated NS representation
* @param src source NS representation
* @return 0 on success, error code on failure
*/
int kr_nsrep_copy_set(struct kr_nsrep *dst, const struct kr_nsrep *src);
/**
* Sort addresses in the query nsrep list by cached RTT.
* if RTT is greater then KR_NS_TIMEOUT, address will placed at the beginning of the
* nsrep list once in cache.ns_tout() milliseconds. Otherwise it will be sorted
* as if it has cached RTT equal to KR_NS_MAX_SCORE + 1.
* @param ns updated kr_nsrep
* @param ctx name resolution context.
* @return 0 or an error code
* @note ns reputation is zeroed and score is set to KR_NS_MAX_SCORE + 1.
*/
KR_EXPORT
int kr_nsrep_sort(struct kr_nsrep *ns, struct kr_context *ctx);
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