Network.DNS.Types.Resolver

Documentation

data FileOrNumericHost

The type to specify a cache server.

Constructors

RCFilePath FilePath

A path for "resolv.conf" where one or more IP addresses of DNS servers should be found on Unix. Default DNS servers are automatically detected on Windows regardless of the value of the file name.

RCHostName HostName

A numeric IP address. Warning: host names are invalid.

RCHostNames [HostName]

Numeric IP addresses. Warning: host names are invalid.

RCHostPort HostName PortNumber

A numeric IP address and port number. Warning: host names are invalid.

Instances

Show FileOrNumericHost

Defined in Network.DNS.Types.Resolver

Methods

showsPrec :: Int -> FileOrNumericHost -> ShowS

show :: FileOrNumericHost -> String

showList :: [FileOrNumericHost] -> ShowS

data CacheConf

Cache configuration for responses.

Constructors

CacheConf

Fields

• maximumTTL :: TTL

  If RR's TTL is higher than this value, this value is used instead.

• pruningDelay :: Int

  Cache pruning interval in seconds.

Instances

Show CacheConf

Defined in Network.DNS.Types.Resolver

Methods

showsPrec :: Int -> CacheConf -> ShowS

show :: CacheConf -> String

showList :: [CacheConf] -> ShowS

defaultCacheConf :: CacheConf

Default cache configuration.

>>> defaultCacheConf
CacheConf {maximumTTL = 300, pruningDelay = 10}

data ResolvConf

Type for resolver configuration. Use defaultResolvConf to create a new value.

An example to use Google's public DNS cache instead of resolv.conf:

>>> let conf = defaultResolvConf { resolvInfo = RCHostName "8.8.8.8" }

An example to use multiple Google's public DNS cache concurrently:

>>> let conf = defaultResolvConf { resolvInfo = RCHostNames ["8.8.8.8","8.8.4.4"], resolvConcurrent = True }

An example to disable EDNS:

>>> let conf = defaultResolvConf { resolvQueryControls = ednsEnabled FlagClear }

An example to enable query result caching:

>>> let conf = defaultResolvConf { resolvCache = Just defaultCacheConf }

An example to disable requesting recursive service.

>>> let conf = defaultResolvConf { resolvQueryControls = rdFlag FlagClear }

An example to set the AD bit in all queries by default.

>>> let conf = defaultResolvConf { resolvQueryControls = adFlag FlagSet }

An example to set the both the AD and CD bits in all queries by default.

>>> let conf = defaultResolvConf { resolvQueryControls = adFlag FlagSet <> cdFlag FlagSet }

An example with an EDNS buffer size of 1216 bytes, which is more robust with IPv6, and the DO bit set to request DNSSEC responses.

>>> let conf = defaultResolvConf { resolvQueryControls = ednsSetUdpSize (Just 1216) <> doFlag FlagSet }

Constructors

ResolvConf

Fields

• resolvInfo :: FileOrNumericHost

  Server information.

• resolvTimeout :: Int

  Timeout in micro seconds.

• resolvRetry :: Int

  The number of retries including the first try.

• resolvConcurrent :: Bool

  Concurrent queries if multiple DNS servers are specified.

• resolvCache :: Maybe CacheConf

  Cache configuration.

• resolvQueryControls :: QueryControls

  Overrides for the default flags used for queries via resolvers that use this configuration.

Instances

Show ResolvConf

Defined in Network.DNS.Types.Resolver

Methods

showsPrec :: Int -> ResolvConf -> ShowS

show :: ResolvConf -> String

showList :: [ResolvConf] -> ShowS

defaultResolvConf :: ResolvConf

Return a default ResolvConf:

• resolvInfo is RCFilePath "/etc/resolv.conf".
• resolvTimeout is 3,000,000 micro seconds.
• resolvRetry is 3.
• resolvConcurrent is False.
• resolvCache is Nothing.
• resolvQueryControls is an empty set of overrides.

data ResolvSeed

Intermediate abstract data type for resolvers. IP address information of DNS servers is generated according to resolvInfo internally. This value can be safely reused for withResolver.

The naming is confusing for historical reasons.

Constructors

ResolvSeed

Fields

• resolvconf :: ResolvConf
• nameservers :: NonEmpty AddrInfo

data Resolver

Abstract data type of DNS Resolver. This includes newly seeded identifier generators for all specified DNS servers and a cache database.

Constructors

Resolver

Fields

• resolvseed :: ResolvSeed
• genIds :: NonEmpty (IO Word16)
• cache :: Maybe Cache