91 lines
3.3 KiB
OCaml
91 lines
3.3 KiB
OCaml
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(** DNS cache - a least recently used cache of DNS responses
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This data structure allows to insert and retrieve entries into a least
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recently used data structure. An [`Entry] weights the cardinality of the
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resource record map, all other entries have a weight of 1.
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The time to live is preserved, and when it is exceeded the entry is no
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longer returned.
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*)
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(* (c) 2017, 2018 Hannes Mehnert, all rights reserved *)
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open Dns
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(** The variant of the rank in the cache. *)
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type rank =
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| ZoneFile
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| ZoneTransfer
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| AuthoritativeAnswer of Rrsig.t option
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| AuthoritativeAuthority of Rrsig.t option
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| ZoneGlue
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| NonAuthoritativeAnswer
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| Additional
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val pp_rank : rank Fmt.t
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(** [pp_rank ppf rank] pretty-prints the [rank] on [ppf]. *)
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val compare_rank : rank -> rank -> int
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(** [compare_rank a b] compares the ranks [a] with [b]. *)
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(** The type of a DNS cache. *)
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type t
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val empty : int -> t
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(** [empty maximum_size] is an empty DNS cache with the maximum size as
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capacity. *)
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val size : t -> int
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(** [size cache] is the number of bindings currently in the [cache]. *)
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val capacity : t -> int
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(** [capacity cache] is the used weight. *)
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val pp : t Fmt.t
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(** [pp ppf t] pretty prints the cache [t] on [ppf]. *)
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(** The polymorphic variant of an entry: a resource record, or no data,
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no domain, or a server failure. *)
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type 'a entry = [
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| `Entry of 'a
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| `No_data of [ `raw ] Domain_name.t * Soa.t
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| `No_domain of [ `raw ] Domain_name.t * Soa.t
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| `Serv_fail of [ `raw ] Domain_name.t * Soa.t
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]
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val pp_entry : 'a Rr_map.key -> 'a entry Fmt.t
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(** [pp_entry ppf entry] pretty-prints [entry] on [ppf]. *)
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val get : t -> int64 -> [ `raw ] Domain_name.t -> 'a Rr_map.key ->
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t * ('a entry * rank, [ `Cache_miss | `Cache_drop ]) result
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(** [get cache timestamp type name] retrieves the query [type, name] from the
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[cache] using [timestamp]. If the time to live is exceeded, a [`Cache_drop]
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is returned. If there is no entry in the cache, a [`Cache_miss] is
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returned. *)
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val get_or_cname : t -> int64 -> [ `raw ] Domain_name.t -> 'a Rr_map.key ->
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t * ([ 'a entry | `Alias of int32 * [`raw] Domain_name.t] * rank,
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[ `Cache_miss | `Cache_drop ]) result
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(** [get_or_cname cache timestamp type name] is the same as [get], but if a
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[`Cache_miss] is encountered, a lookup for an alias (CNAME) is done. *)
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val get_any : t -> int64 -> [ `raw ] Domain_name.t ->
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t * ([ `Entries of Rr_map.t
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| `No_domain of [ `raw ] Domain_name.t * Soa.t ] * rank,
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[ `Cache_miss | `Cache_drop ]) result
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(** [get_any cache timestamp name] retrieves all resource records for [name]
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in [cache]. *)
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val get_nsec3 : t -> int64 -> [ `raw ] Domain_name.t ->
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t * (([`raw] Domain_name.t * int32 * Nsec3.t * rank) list, [ `Cache_miss | `Cache_drop ]) result
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(** [get_nsec3 cache timestamp name] retrieves all nsec3 resource records for
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the zone [name]. *)
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val set : t -> int64 -> [ `raw ] Domain_name.t -> 'a Rr_map.key -> rank ->
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'a entry -> t
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(** [set cache timestamp type name rank value] attempts to insert
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[type, name, value] into the [cache] using the [timestamp] and [rank]. If
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an entry already exists with a higher [rank], the [cache] is unchanged. *)
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val remove : t -> [ `raw ] Domain_name.t -> t
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(** [remove cache name] removes [name] from [cache]. *)
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