352 lines
16 KiB
Text
352 lines
16 KiB
Text
module App.Validation.DNS where
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import Prelude (apply, between, bind, map, pure, ($), (-), (<), (<>), (==))
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import Control.Alt ((<|>))
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import Data.Array as A
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import Data.Either (Either(..))
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import Data.Maybe (Maybe(..), maybe, fromMaybe)
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import Data.String.CodeUnits as CU
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import Data.String as S
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import Data.Validation.Semigroup (V, invalid, toEither)
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import App.Type.ResourceRecord (ResourceRecord, emptyRR, Mechanism, Modifier)
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import App.Type.ResourceRecord (MechanismType(..), ModifierType(..)) as RR
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import GenericParser.SomeParsers as SomeParsers
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import GenericParser.Parser as G
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import GenericParser.DomainParser.Common (DomainError) as DomainParser
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import GenericParser.DomainParser (sub_eof) as DomainParser
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import GenericParser.IPAddress as IPAddress
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import GenericParser.RFC5234 as RFC5234
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import App.Type.DKIM as DKIM
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import App.Type.DMARC as DMARC
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import App.Type.CAA as CAA
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-- | **History:**
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-- | The module once used dedicated types for each type of RR.
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-- | That comes with several advantages.
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-- | First, type verification was a thing, and function were dedicated to a certain type of record.
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-- | Second, these dedicated types used strings for their fields,
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-- | which simplifies the typing when dealing with forms.
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-- | Finally, the validation was a way to convert dedicated types (used in forms)
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-- | to the general type (used for network serialization).
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-- | This ensures each resource record is verified before being sent to `dnsmanagerd`.
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-- |
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-- | The problem is that, with dedicated types, you are then required to have dedicated functions.
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-- | Conversion functions are also required.
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-- |
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-- | Maybe the code will change again in the future, but for now it will be enough.
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data Error
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= UNKNOWN
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| VEIPv4 (G.Error IPAddress.IPv4Error)
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| VEIPv6 (G.Error IPAddress.IPv6Error)
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| VEName (G.Error DomainParser.DomainError)
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| VETTL Int Int Int
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| VETXT (G.Error TXTError)
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| VECNAME (G.Error DomainParser.DomainError)
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| VENS (G.Error DomainParser.DomainError)
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| VEMX (G.Error DomainParser.DomainError)
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| VEPriority Int Int Int
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| VESRV (G.Error DomainParser.DomainError)
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| VEPort Int Int Int
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| VEWeight Int Int Int
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| VEDMARCpct Int Int Int
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| VEDMARCri Int Int Int
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| VECAAflag Int Int Int -- CAA flag should be between 0 and 255 (1 byte).
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-- SPF
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| VESPFMechanismName (G.Error DomainParser.DomainError)
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| VESPFMechanismIPv4 (G.Error IPAddress.IPv4Error)
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| VESPFMechanismIPv6 (G.Error IPAddress.IPv6Error)
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| VESPFModifierName (G.Error DomainParser.DomainError)
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| DKIMInvalidKeySize Int Int
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type AVErrors = Array Error
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-- | Current default values.
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min_ttl = 30 :: Int
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max_ttl = 86000 :: Int
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max_txt = 500 :: Int
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min_priority = 0 :: Int
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max_priority = 65535 :: Int
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min_port = 0 :: Int
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max_port = 65535 :: Int
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min_weight = 0 :: Int
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max_weight = 65535 :: Int
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-- Functions handling network-related structures (ResourceRecord).
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type RRPriority = Maybe Int
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type RRPort = Maybe Int
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type RRWeight = Maybe Int
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type RRMname = Maybe String
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type RRRname = Maybe String
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type RRSerial = Maybe Int
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type RRRefresh = Maybe Int
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type RRRetry = Maybe Int
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type RRExpire = Maybe Int
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type RRMinttl = Maybe Int
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data TXTError
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= TXTInvalidCharacter
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| TXTTooLong Int Int -- max current
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-- | TODO: `txt_parser` is currently accepting any printable character (`vchar + sp`).
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txt_parser :: G.Parser TXTError String
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txt_parser = do pos <- G.current_position
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v <- A.many (RFC5234.vchar <|> RFC5234.sp)
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e <- G.tryMaybe SomeParsers.eof
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pos2 <- G.current_position
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case e of
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Nothing -> G.errorParser $ Just TXTInvalidCharacter
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Just _ -> do
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let nbchar = pos2 - pos
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if nbchar < max_txt
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then pure $ CU.fromCharArray v
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else G.Parser \_ -> G.failureError pos (Just $ TXTTooLong max_txt nbchar)
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-- | `parse` enables to run any parser based on `GenericParser` and provide a validation error.
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-- | The actual validation error contains the parser's error including the position.
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parse :: forall e v. G.Parser e v -> String -> ((G.Error e) -> Error) -> V (Array Error) v
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parse (G.Parser p) str c = case p { string: str, position: 0 } of
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Left x -> invalid $ [c x]
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Right x -> pure x.result
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validationA :: ResourceRecord -> V (Array Error) ResourceRecord
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validationA form = ado
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name <- parse DomainParser.sub_eof form.name VEName
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ttl <- is_between min_ttl max_ttl form.ttl VETTL
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target <- parse IPAddress.ipv4 form.target VEIPv4
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in emptyRR { rrid = form.rrid, readonly = form.readonly, rrtype = "A", name = name, ttl = ttl, target = target
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, token = form.token }
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validationAAAA :: ResourceRecord -> V (Array Error) ResourceRecord
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validationAAAA form = ado
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name <- parse DomainParser.sub_eof form.name VEName
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ttl <- is_between min_ttl max_ttl form.ttl VETTL
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-- use read_input to get unaltered input (the IPv6 parser expands the input)
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target <- parse (G.read_input IPAddress.ipv6) form.target VEIPv6
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in emptyRR { rrid = form.rrid, readonly = form.readonly, rrtype = "AAAA", name = name, ttl = ttl, target = target
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, token = form.token }
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validationTXT :: ResourceRecord -> V (Array Error) ResourceRecord
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validationTXT form = ado
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name <- parse DomainParser.sub_eof form.name VEName
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ttl <- is_between min_ttl max_ttl form.ttl VETTL
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target <- parse txt_parser form.target VETXT
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in emptyRR { rrid = form.rrid, readonly = form.readonly, rrtype = "TXT", name = name, ttl = ttl, target = target }
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validationCNAME :: ResourceRecord -> V (Array Error) ResourceRecord
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validationCNAME form = ado
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name <- parse DomainParser.sub_eof form.name VEName
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ttl <- is_between min_ttl max_ttl form.ttl VETTL
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target <- parse DomainParser.sub_eof form.target VECNAME
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in emptyRR { rrid = form.rrid, readonly = form.readonly, rrtype = "CNAME", name = name, ttl = ttl, target = target }
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validationNS :: ResourceRecord -> V (Array Error) ResourceRecord
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validationNS form = ado
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name <- parse DomainParser.sub_eof form.name VEName
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ttl <- is_between min_ttl max_ttl form.ttl VETTL
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target <- parse DomainParser.sub_eof form.target VENS
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in emptyRR { rrid = form.rrid, readonly = form.readonly, rrtype = "NS", name = name, ttl = ttl, target = target }
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is_between :: Int -> Int -> Int -> (Int -> Int -> Int -> Error) -> V (Array Error) Int
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is_between min max n ve = if between min max n
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then pure n
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else invalid [ve min max n]
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validationMX :: ResourceRecord -> V (Array Error) ResourceRecord
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validationMX form = ado
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name <- parse DomainParser.sub_eof form.name VEName
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ttl <- is_between min_ttl max_ttl form.ttl VETTL
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target <- parse DomainParser.sub_eof form.target VEMX
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priority <- is_between min_priority max_priority (maybe 0 id form.priority) VEPriority
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in emptyRR { rrid = form.rrid, readonly = form.readonly, rrtype = "MX"
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, name = name, ttl = ttl, target = target, priority = Just priority }
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validationSRV :: ResourceRecord -> V (Array Error) ResourceRecord
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validationSRV form = ado
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name <- parse DomainParser.sub_eof form.name VEName
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ttl <- is_between min_ttl max_ttl form.ttl VETTL
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target <- parse DomainParser.sub_eof form.target VESRV
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priority <- is_between min_priority max_priority (maybe 0 id form.priority) VEPriority
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port <- is_between min_port max_port (maybe 0 id form.port) VEPort
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weight <- is_between min_weight max_weight (maybe 0 id form.weight) VEWeight
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in emptyRR { rrid = form.rrid, readonly = form.readonly, rrtype = "SRV"
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, name = name, ttl = ttl, target = target
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, priority = Just priority, port = Just port, protocol = form.protocol, weight = Just weight }
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-- My version of "map" lol.
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verification_loop :: forall a e. (a -> V (Array e) a) -> Array a -> V (Array e) (Array a)
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verification_loop _ [] = pure []
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verification_loop f arr =
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case A.head arr, A.tail arr of
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Nothing, _ -> pure []
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Just value, tail -> ado
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v <- f value
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following <- verification_loop f $ maybe [] id tail
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in [v] <> following
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first :: forall a b. a -> b -> a
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first a _ = a
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or_nothing :: forall e. G.Parser e String -> G.Parser e String
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or_nothing p = do v <- G.tryMaybe p
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e <- G.tryMaybe SomeParsers.eof
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case v, e of
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Just value, _ -> pure value
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_, Just _ -> pure ""
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Nothing, Nothing -> p -- at least give the right error results
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-- | `validate_SPF_mechanism` validates the different values for each mechanism.
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-- | A and MX can both either doesn't have a value or a domain name.
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-- | EXISTS requires a domain name.
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-- |
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-- | **What differs from RFC7208**:
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-- | Some features of the mechanisms described in RFC7208 are lacking.
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-- | For instance, INCLUDE, A, MX, PTR and EXISTS accept domain *specs* not simply domain *names*.
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-- | Also, some of them should accept a CIDR, which currently isn't a thing.
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-- |
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-- | TODO: I don't intend to implement the full RFC7208, but accepting CIDR can be done.
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validate_SPF_mechanism :: Mechanism -> V (Array Error) Mechanism
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validate_SPF_mechanism m = case m.t of
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-- RFC: `a = "a" [ ":" domain-spec ] [ dual-cidr-length ]`
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RR.A -> test (or_nothing DomainParser.sub_eof) VESPFMechanismName
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-- RFC: `mx = "mx" [ ":" domain-spec ] [ dual-cidr-length ]`
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RR.MX -> test (or_nothing DomainParser.sub_eof) VESPFMechanismName
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-- RFC: `exists = "exists" ":" domain-spec`
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RR.EXISTS -> test DomainParser.sub_eof VESPFMechanismName
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-- RFC: `ptr = "ptr" [ ":" domain-spec ]`
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RR.PTR -> test (or_nothing DomainParser.sub_eof) VESPFMechanismName
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-- RFC: `ip4 = "ip4" ":" ip4-network [ ip4-cidr-length ]`
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RR.IP4 -> test (IPAddress.ipv4_range <|> IPAddress.ipv4) VESPFMechanismIPv4
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-- RFC: `ip6 = "ip6" ":" ip6-network [ ip6-cidr-length ]`
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RR.IP6 -> test (IPAddress.ipv6_range <|> IPAddress.ipv6) VESPFMechanismIPv6
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-- RFC: `include = "include" ":" domain-spec`
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RR.INCLUDE -> test DomainParser.sub_eof VESPFMechanismName
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where
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test :: forall e. G.Parser e String -> ((G.Error e) -> Error) -> V (Array Error) Mechanism
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test p e = ado
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name <- parse p m.v e
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in first m name -- name is discarded
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validate_SPF_modifier :: Modifier -> V (Array Error) Modifier
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validate_SPF_modifier m = case m.t of
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RR.EXP -> ado
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name <- parse DomainParser.sub_eof m.v VESPFModifierName
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in first m name -- name is discarded
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RR.REDIRECT -> ado
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name <- parse DomainParser.sub_eof m.v VESPFModifierName
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in first m name -- name is discarded
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validationSPF :: ResourceRecord -> V (Array Error) ResourceRecord
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validationSPF form = ado
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name <- parse DomainParser.sub_eof form.name VEName
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ttl <- is_between min_ttl max_ttl form.ttl VETTL
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mechanisms <- verification_loop validate_SPF_mechanism (maybe [] id form.mechanisms)
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modifiers <- verification_loop validate_SPF_modifier (maybe [] id form.modifiers)
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-- No need to validate the target, actually, it will be completely discarded.
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-- The different specific entries replace `target` completely.
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in emptyRR { rrid = form.rrid, readonly = form.readonly, rrtype = "SPF"
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, name = name, ttl = ttl, target = "" -- `target` is discarded!
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, v = form.v, mechanisms = Just mechanisms
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, modifiers = Just modifiers, q = form.q }
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-- | Accepted RSA key sizes = 1024, 2048 or 4096 bits, 256 bits for ED25519.
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-- |
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-- | Since the public key representation for the RSA algorithm is in PKCS format (RFC 5958)
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-- | then converted in PEM (RFC 7468), and knowing this format enables some optional parameters,
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-- | it is not possible to expect an exact size for the public key input.
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-- | Consequently, we expect *at least* an input of 128 bytes for public key, loosely leading
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-- | to accept key sizes of at least 1024 bits. Maximum allowed key size is also arbitrary.
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rsa_min_key_size = 128 :: Int
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rsa_max_key_size = 1000 :: Int
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-- | Contrary to RSA, ED25519 doesn't use a PEM-converted PKCS representation to exchange
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-- | public keys, and the key size is 256 bits (32 bytes).
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-- | This key is converted directly in base64, leading to a simple 44-byte key representation.
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ed25519_key_size = 44 :: Int
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verify_public_key :: DKIM.SignatureAlgorithm -> DKIM.PublicKey -> V (Array Error) DKIM.PublicKey
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verify_public_key signalgo key = case signalgo of
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DKIM.RSA -> ado
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k <- if between rsa_min_key_size rsa_max_key_size (S.length key)
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then pure key
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else invalid [DKIMInvalidKeySize rsa_min_key_size rsa_max_key_size]
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in k
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DKIM.ED25519 -> ado
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k <- if S.length key == ed25519_key_size
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then pure key
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else invalid [DKIMInvalidKeySize ed25519_key_size ed25519_key_size]
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in k
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validationDKIM :: ResourceRecord -> V (Array Error) ResourceRecord
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validationDKIM form =
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let dkim = fromMaybe DKIM.emptyDKIMRR form.dkim
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in ado
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name <- parse DomainParser.sub_eof form.name VEName
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ttl <- is_between min_ttl max_ttl form.ttl VETTL
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-- TODO: v n
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p <- verify_public_key (fromMaybe DKIM.RSA dkim.k) dkim.p
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-- No need to validate the target, actually, it will be completely discarded.
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-- The different specific entries replace `target` completely.
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in emptyRR { rrid = form.rrid, readonly = form.readonly, rrtype = "DKIM"
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, name = name, ttl = ttl, target = "" -- `target` is discarded!
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, dkim = Just $ dkim { p = p } }
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validationDMARC :: ResourceRecord -> V (Array Error) ResourceRecord
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validationDMARC form =
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let dmarc = fromMaybe DMARC.emptyDMARCRR form.dmarc
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in ado
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name <- parse DomainParser.sub_eof form.name VEName
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ttl <- is_between min_ttl max_ttl form.ttl VETTL
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pct <- is_between 0 100 (fromMaybe 100 dmarc.pct) VEDMARCpct
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ri <- is_between 0 1000000 (fromMaybe 86400 dmarc.ri) VEDMARCri
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-- No need to validate the target, actually, it will be completely discarded.
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-- The different specific entries replace `target` completely.
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in emptyRR { rrid = form.rrid, readonly = form.readonly, rrtype = "DMARC"
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, name = name, ttl = ttl, target = "" -- `target` is discarded!
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, dmarc = Just $ dmarc { pct = Just pct, ri = Just ri } }
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validationCAA :: ResourceRecord -> V (Array Error) ResourceRecord
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validationCAA form =
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let caa = fromMaybe CAA.emptyCAARR form.caa
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in ado
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name <- parse DomainParser.sub_eof form.name VEName
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ttl <- is_between min_ttl max_ttl form.ttl VETTL
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flag <- is_between 0 255 caa.flag VECAAflag
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-- TODO: verify the `value` field.
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-- No need to validate the target, actually, it will be completely discarded.
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-- The different specific entries replace `target` completely.
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in emptyRR { rrid = form.rrid, readonly = form.readonly, rrtype = "CAA"
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, name = name, ttl = ttl, target = "" -- `target` is discarded!
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, caa = Just $ caa { flag = flag } }
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validation :: ResourceRecord -> Either (Array Error) ResourceRecord
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validation entry = case entry.rrtype of
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"A" -> toEither $ validationA entry
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"AAAA" -> toEither $ validationAAAA entry
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"TXT" -> toEither $ validationTXT entry
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"CNAME" -> toEither $ validationCNAME entry
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"NS" -> toEither $ validationNS entry
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"MX" -> toEither $ validationMX entry
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"CAA" -> toEither $ validationCAA entry
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"SRV" -> toEither $ validationSRV entry
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"SPF" -> toEither $ validationSPF entry
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"DKIM" -> toEither $ validationDKIM entry
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"DMARC" -> toEither $ validationDMARC entry
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_ -> toEither $ invalid [UNKNOWN]
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id :: forall a. a -> a
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id x = x
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