Upstream Fetch Processing. More...

#include <io_fetch.h>

Inheritance diagram for isc::asiodns::IOFetch:

Classes
class	Callback
	I/O Fetch Callback. More...

Public Types
enum	{ STAGING_LENGTH = 8192 }
	Integer Constants. More...

enum	Origin { NONE = 0, OPEN = 1, SEND = 2, RECEIVE = 3, CLOSE = 4 }
	Origin of Asynchronous I/O Call. More...

enum	Protocol { UDP = 0, TCP = 1 }
	Protocol to use on the fetch. More...

enum	Result { SUCCESS = 0, TIME_OUT = 1, STOPPED = 2, NOTSET = 3 }
	Result of Upstream Fetch. More...

Public Member Functions
	IOFetch (Protocol protocol, isc::asiolink::IOService &service, const isc::dns::Question &question, const isc::asiolink::IOAddress &address, uint16_t port, isc::util::OutputBufferPtr &buff, Callback *cb, int wait=-1, bool edns=true)
	Constructor. More...

	IOFetch (Protocol protocol, isc::asiolink::IOService &service, isc::dns::ConstMessagePtr query_message, const isc::asiolink::IOAddress &address, uint16_t port, isc::util::OutputBufferPtr &buff, Callback *cb, int wait=-1)
	Constructor This constructor has one parameter "query_message", which is the shared_ptr to a full query message. More...

	IOFetch (Protocol protocol, isc::asiolink::IOService &service, isc::util::OutputBufferPtr &outpkt, const isc::asiolink::IOAddress &address, uint16_t port, isc::util::OutputBufferPtr &buff, Callback *cb, int wait=-1)
	Constructor. More...

Protocol	getProtocol () const
	Return Current Protocol. More...

void	operator() (boost::system::error_code ec=boost::system::error_code(), size_t length=0)
	Coroutine entry point. More...

void	stop (Result reason=STOPPED)
	Terminate query. More...

Detailed Description

Upstream Fetch Processing.

IOFetch is the class used to send upstream fetches and to handle responses.

Parameters

E	Endpoint type to use.

Definition at line 45 of file io_fetch.h.

Member Enumeration Documentation

anonymous enum

Integer Constants.

Enumerator
STAGING_LENGTH	Size of staging buffer.

Definition at line 81 of file io_fetch.h.

enum isc::asiodns::IOFetch::Origin

Origin of Asynchronous I/O Call.

Indicates what initiated an asynchronous I/O call and used in deciding what error message to output if the I/O fails.

Enumerator
NONE	No asynchronous call outstanding.
OPEN
SEND
RECEIVE
CLOSE

Definition at line 57 of file io_fetch.h.

enum isc::asiodns::IOFetch::Protocol

Protocol to use on the fetch.

Enumerator
UDP
TCP

Definition at line 48 of file io_fetch.h.

enum isc::asiodns::IOFetch::Result

Result of Upstream Fetch.

Note that this applies to the status of I/Os in the fetch - a fetch that resulted in a packet being received from the server is a SUCCESS, even if the contents of the packet indicate that some error occurred.

Enumerator
SUCCESS	Success, fetch completed.
TIME_OUT	Failure, fetch timed out.
STOPPED	Control code, fetch has been stopped.
NOTSET	For testing, indicates value not set.

Definition at line 70 of file io_fetch.h.

Constructor & Destructor Documentation

isc::asiodns::IOFetch::IOFetch	(	Protocol	protocol,
		isc::asiolink::IOService &	service,
		const isc::dns::Question &	question,
		const isc::asiolink::IOAddress &	address,
		uint16_t	port,
		isc::util::OutputBufferPtr &	buff,
		Callback *	cb,
		int	wait = `-1`,
		bool	edns = `true`
	)

Constructor.

IOFetch Constructor - just initialize the private data.

Creates the object that will handle the upstream fetch.

Parameters

protocol	Fetch protocol, either IOFetch::TCP or IOFetch::UDP
service	I/O Service object to handle the asynchronous operations.
question	DNS question to send to the upstream server.
address	IP address of upstream server
port	Port to which to connect on the upstream server
buff	Output buffer into which the response (in wire format) is written (if a response is received).
cb	Callback object containing the callback to be called when we terminate. The caller is responsible for managing this object and deleting it if necessary.
wait	Timeout for the fetch (in ms). The default value of -1 indicates no timeout.
edns	true if the request should be EDNS. The default value is true.

Definition at line 156 of file io_fetch.cc.

isc::asiodns::IOFetch::IOFetch	(	Protocol	protocol,
		isc::asiolink::IOService &	service,
		isc::dns::ConstMessagePtr	query_message,
		const isc::asiolink::IOAddress &	address,
		uint16_t	port,
		isc::util::OutputBufferPtr &	buff,
		Callback *	cb,
		int	wait = `-1`
	)

Constructor This constructor has one parameter "query_message", which is the shared_ptr to a full query message.

It's different with above constructor which has only question section. All other parameters are same.

Parameters

protocol	Fetch protocol, either IOFetch::TCP or IOFetch::UDP
service	I/O Service object to handle the asynchronous operations.
query_message	the shared_ptr to a full query message got from a query client.
address	IP address of upstream server
port	Port to which to connect on the upstream server
buff	Output buffer into which the response (in wire format) is written (if a response is received).
cb	Callback object containing the callback to be called when we terminate. The caller is responsible for managing this object and deleting it if necessary.
wait	Timeout for the fetch (in ms). The default value of -1 indicates no timeout.

Definition at line 176 of file io_fetch.cc.

isc::asiodns::IOFetch::IOFetch	(	Protocol	protocol,
		isc::asiolink::IOService &	service,
		isc::util::OutputBufferPtr &	outpkt,
		const isc::asiolink::IOAddress &	address,
		uint16_t	port,
		isc::util::OutputBufferPtr &	buff,
		Callback *	cb,
		int	wait = `-1`
	)

Constructor.

Creates the object that will handle the upstream fetch.

Parameters

protocol	Fetch protocol, either IOFetch::TCP or IOFetch::UDP
service	I/O Service object to handle the asynchronous operations.
outpkt	Packet to send to upstream server. Note that the QID (first two bytes of the packet) may be altered in the sending.
buff	Output buffer into which the response (in wire format) is written (if a response is received).
cb	Callback object containing the callback to be called when we terminate. The caller is responsible for managing this object and deleting it if necessary.
address	IP address of upstream server
port	Port to which to connect on the upstream server (default = 53)
wait	Timeout for the fetch (in ms). The default value of -1 indicates no timeout.

Definition at line 165 of file io_fetch.cc.

Member Function Documentation

IOFetch::Protocol isc::asiodns::IOFetch::getProtocol ( ) const

Return Current Protocol.

Returns: Protocol associated with this IOFetch object.

Definition at line 223 of file io_fetch.cc.

void isc::asiodns::IOFetch::operator()	(	boost::system::error_code	ec = `boost::system::error_code()`,
		size_t	length = `0`
	)

Coroutine entry point.

The function operator is implemented with the "stackless coroutine" pattern; see boost/asio/coroutine.hpp for details.

The operator() method is the method in which the coroutine code enters this object when an operation has been completed.

Parameters

ec	Error code, the result of the last asynchronous I/O operation.
length	Amount of data received on the last asynchronous read

Generate the upstream query and render it to wire format This is done in a different scope to allow inline variable declarations.

We are done

Definition at line 231 of file io_fetch.cc.

References isc::asiodns::ASIODNS_OPEN_SOCKET, isc::asiodns::ASIODNS_READ_DATA, isc::asiodns::ASIODNS_SEND_DATA, isc::asiodns::ASIODNS_UNKNOWN_ORIGIN, STAGING_LENGTH, stop(), SUCCESS, and TIME_OUT.

Here is the call graph for this function:

void isc::asiodns::IOFetch::stop ( Result reason = STOPPED )

Terminate query.

This method can be called at any point. It terminates the current query with the specified reason.

Parameters

reason Reason for terminating the query

Definition at line 334 of file io_fetch.cc.

References isc::asiodns::ASIODNS_FETCH_COMPLETED, isc::asiodns::ASIODNS_FETCH_STOPPED, isc::asiodns::ASIODNS_READ_TIMEOUT, isc::asiodns::ASIODNS_UNKNOWN_RESULT, LOG_DEBUG, LOG_ERROR, isc::asiodns::logger, STOPPED, SUCCESS, and TIME_OUT.

Referenced by operator()().

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

Classes

Public Types

Public Member Functions

Detailed Description

Member Enumeration Documentation

Constructor & Destructor Documentation

Member Function Documentation