OW32::CAsyncResolver Class Reference

An asynchronous name resolver using IO completion ports. More...

#include <AsyncResolver.h>

Inheritance diagram for OW32::CAsyncResolver:

List of all members.

Public Member Functions
	CAsyncResolver ()
	Construct an uninitialised resolver.
AsyncResolverError	initialise (const CAsyncResolverOptions *pOptions, HANDLE hIoPort, CFileWatcher *pFileWatcher=NULL, const char *random_data=NULL)
	Initialise the resolver.
	~CAsyncResolver ()
	Destructor for final cleanup.
AsyncResolverError	terminate ()
	Shutdown the resolver.
HANDLE	getIoCompletionPort ()
	Return the IO completion port in use.
void	gethostbyname (CAsyncResolverHostCallback *pCallback, void *context, const char *name, int family)
	Asynchronous version of gethostbynmae.
void	gethostbyaddr (CAsyncResolverHostCallback *pCallback, void *context, const void *addr, int addrlen, int family)
	Asynchronous version of gethostbyaddr.
void	search (CAsyncResolverCallback *pCallback, void *context, const char *name, int dnsclass, int type)
	Asynchronous version of search.
void	sendQuery (CAsyncResolverQuery *query)
	Initiate transmission of a CAsyncResolverQuery object.
AsyncResolverError	getHostsDB (CAsyncResolverHostsDBPtr &hostsDB)
	Get the hosts file database, reading it in if this is the first call.
unsigned int	random (unsigned int n)
	Return a random number modulo n.
const CAsyncResolverOptions *	getOptions () const
	Return the options object in use by this resolver.
void	OnAnswer (size_t serverIndex, bool fTCP, BYTE *abuf, size_t alen)
	Callback from CAsyncResolverServer.
void	OnError (size_t serverIndex, bool fTCP, AsyncResolverError status, CAsyncResolverQuery *query)
	Callback from CAsyncResolverServer.
virtual void	onTimeout (LPVOID key)
	Called by the I/O timeout manager when a timeout occurs.
virtual bool	drainTimeout (CIoTimeoutCallback *pCallback, LPVOID key)
	Called by the I/O timeout manager during timeout queue draining.
Static Public Member Functions
AsyncResolverError	expandName (const unsigned char *encoded, const unsigned char *abuf, size_t alen, char **s, size_t *enclen)
	Utility function to expand a name in a DNS packet.
AsyncResolverError	getHostEnt (FILE *fp, struct hostent **host)
	Utility function to get a hostent structure by reading a line from a 'hosts' style file.
void	freeHostEnt (struct hostent *host)
	Utility function to free a hostent structure where all fields are allocated with malloc (e.g.
const TCHAR *	describeError (AsyncResolverError code)
	Utility function to provide a textual description of an error code.
AsyncResolverError	readLine (FILE *fp, char **buf, size_t *bufsize)
	Utility function to read a line from a file.

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Detailed Description

An asynchronous name resolver using IO completion ports.

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Constructor & Destructor Documentation

OW32::CAsyncResolver::CAsyncResolver (   )  [inline]

Construct an uninitialised resolver. initialise must be called before use.

OW32::CAsyncResolver::~CAsyncResolver (   )

Destructor for final cleanup. Must call terminate() first.

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Member Function Documentation

const TCHAR* OW32::CAsyncResolver::describeError (  AsyncResolverError  code  )  [static]

Utility function to provide a textual description of an error code. Currently only English is supported. Parameters: code  The error code to describe Returns: The error code description, never NULL.

virtual bool OW32::CAsyncResolver::drainTimeout (  CIoTimeoutCallback *  pCallback, LPVOID  key )  [virtual]

Called by the I/O timeout manager during timeout queue draining. Not to be called directly. Implements OW32::CIoTimeoutDrainCallback.

AsyncResolverError OW32::CAsyncResolver::expandName (  const unsigned char *  encoded, const unsigned char *  abuf, size_t  alen, char **  s, size_t *  enclen )  [static]

Utility function to expand a name in a DNS packet. Parameters: encoded  The encoded name abuf  The answer packet alen  The length of the answer packet s  Output - a NULl terminated string allocated with malloc that is the expanded name enclen  The length of the encoded name Returns: ARES_SUCCESS on success, otherwise an appropriate error code.

void OW32::CAsyncResolver::freeHostEnt (  struct hostent *  host  )  [static]

Utility function to free a hostent structure where all fields are allocated with malloc (e.g. from getHostEnt). Parameters: host  The structure to free

void OW32::CAsyncResolver::gethostbyaddr (  CAsyncResolverHostCallback *  pCallback, void *  context, const void *  addr, int  addrlen, int  family )

Asynchronous version of gethostbyaddr. Parameters: pCallback  The callback to inform of errors/responses context  Arbitrary context data for the callback addr  The address to resolve addrlen  The length of the address to resolve family  Only AF_INET is currently supported Only "struct in_addr" is supported for the address (corresponding to only AF_INET being supported). All errors are reported via the callback

void OW32::CAsyncResolver::gethostbyname (  CAsyncResolverHostCallback *  pCallback, void *  context, const char *  name, int  family )

Asynchronous version of gethostbynmae. Parameters: pCallback  The callback to inform of errors/responses context  Arbitrary context data for the callback name  The name to resolve family  Only AF_INET is currently supported All errors are reported via the callback

AsyncResolverError OW32::CAsyncResolver::getHostEnt (  FILE *  fp, struct hostent **  host )  [static]

Utility function to get a hostent structure by reading a line from a 'hosts' style file. Parameters: fp  The file to read from host  Output, the hostent structure Returns: ARES_SUCCESS on success, otherwise an appropriate error code.

AsyncResolverError OW32::CAsyncResolver::getHostsDB (  CAsyncResolverHostsDBPtr &  hostsDB  )

Get the hosts file database, reading it in if this is the first call. Parameters: hostsDB  The hosts database cache. Returns NULL if no change monitoring object is configured, in this case the caller is expected to parse the hosts file. Returns: ARES_SUCCESS if database read OK, otherwise an error code

AsyncResolverError OW32::CAsyncResolver::initialise (  const CAsyncResolverOptions *  pOptions, HANDLE  hIoPort, CFileWatcher *  pFileWatcher = NULL, const char *  random_data = NULL )

Initialise the resolver. Parameters: pOptions  An options object specifying nameservers, timeouts and the like. The options object must be initialised. hIoPort  The I/O completion port to use pFileWatcher  The file watcher to use for monitoring for hosts file changes. If none is set, the hosts file will be re-read for each query. random_data  128 bytes of data used to initialise the random number generator, may be NULL, if so default values will be used. Returns: ARES_SUCCESS if successful, or an error code.

void OW32::CAsyncResolver::OnAnswer (  size_t  serverIndex, bool  fTCP, BYTE *  abuf, size_t  alen )

Callback from CAsyncResolverServer. Not for direct use.

void OW32::CAsyncResolver::OnError (  size_t  serverIndex, bool  fTCP, AsyncResolverError  status, CAsyncResolverQuery *  query )

Callback from CAsyncResolverServer. Not for direct use.

virtual void OW32::CAsyncResolver::onTimeout (  LPVOID  key  )  [virtual]

Called by the I/O timeout manager when a timeout occurs. Not to be called directly. Implements OW32::CIoTimeoutCallback.

unsigned int OW32::CAsyncResolver::random (  unsigned int  n  )

Return a random number modulo n. If n is 0, 0 is returned.

AsyncResolverError OW32::CAsyncResolver::readLine (  FILE *  fp, char **  buf, size_t *  bufsize )  [static]

Utility function to read a line from a file. Parameters: fp  The file to read from buf  The buffer to read into (malloc'd, may be NULL initially) bufsize  The size of the buffer (in/out) Returns: ARES_SUCCESS on success, otherwise an appropriate error code.

void OW32::CAsyncResolver::search (  CAsyncResolverCallback *  pCallback, void *  context, const char *  name, int  dnsclass, int  type )

Asynchronous version of search. Parameters: pCallback  The callback to inform of errors/responses context  Arbitrary context data for the callback name  The name to resolve dnsclass  The dns class of the query type  The dns type of the query All errors are reported via the callback

void OW32::CAsyncResolver::sendQuery (  CAsyncResolverQuery *  query  )

Initiate transmission of a CAsyncResolverQuery object. Parameters: query  The query to transmit All errors are reported to the query's callback object.

AsyncResolverError OW32::CAsyncResolver::terminate (   )

Shutdown the resolver. Must be called before disposing of the resolver object.

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The documentation for this class was generated from the following file:

• AsyncResolver.h

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