hsdns-1.3: Asynchronous DNS Resolver Source code Contents Index

ADNS Portability portable Stability provisional Maintainer simons@cryp.to

Description

An asynchronous DNS resolver based on GNU ADNS http://www.gnu.org/software/adns/. You should link your program with the threaded runtime-system when using this module. In GHC, this is accomplished by specifying -threaded on the command-line.

Synopsis

type Resolver = String -> RRType -> [QueryFlag] -> IO (MVar Answer) initResolver :: [InitFlag] -> (Resolver -> IO a) -> IO a data InitFlag = NoEnv | NoErrPrint | NoServerWarn | Debug | LogPid | NoAutoSys | Eintr | NoSigPipe | CheckC_EntEx | CheckC_Freq queryA :: Resolver -> HostName -> IO (Maybe [HostAddress]) queryPTR :: Resolver -> HostAddress -> IO (Maybe [HostName]) queryMX :: Resolver -> HostName -> IO (Maybe [(HostName, HostAddress)]) dummyDNS :: Resolver

Documentation

type Resolver = String -> RRType -> [QueryFlag] -> IO (MVar Answer) Source

A Resolver is an IO computation which -- given the name and type of the record to query -- returns an MVar that will eventually contain the Answer from the Domain Name System.

initResolver :: [InitFlag] -> (Resolver -> IO a) -> IO a Source

Run the given IO computation with an Initialized Resolver. Note that resolver functions can be shared, and should be shared between any number of IO threads. You may use multiple resolvers, of course, but doing so defeats the purpose of an asynchronous resolver.

data InitFlag Source

Constructors NoEnv do not look at environment NoErrPrint never print output to stderr (Debug overrides) NoServerWarn do not warn to stderr about duff nameservers etc Debug enable all output to stderr plus Debug msgs LogPid include process id in diagnostic output NoAutoSys do not make syscalls at every opportunity Eintr allow adnsSynch to return eINTR NoSigPipe application has SIGPIPE set to SIG_IGN, do not protect CheckC_EntEx do consistency checks on entry/exit to adns functions CheckC_Freq do consistency checks very frequently (slow!) Instances Bounded InitFlag Enum InitFlag Eq InitFlag Show InitFlag

queryA :: Resolver -> HostName -> IO (Maybe [HostAddress]) Source

queryPTR :: Resolver -> HostAddress -> IO (Maybe [HostName]) Source

queryMX :: Resolver -> HostName -> IO (Maybe [(HostName, HostAddress)]) Source

dummyDNS :: Resolver Source

Use this function to disable DNS resolving. It will always return (Answer sSYSTEMFAIL Nothing (Just host) (-1) []).

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