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/*******************************************************************************
* shroudBNC - an object-oriented framework for IRC *
* Copyright (C) 2005-2007 Gunnar Beutner *
* *
* This program is free software; you can redistribute it and/or *
* modify it under the terms of the GNU General Public License *
* as published by the Free Software Foundation; either version 2 *
* of the License, or (at your option) any later version. *
* *
* This program is distributed in the hope that it will be useful, *
* but WITHOUT ANY WARRANTY; without even the implied warranty of *
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the *
* GNU General Public License for more details. *
* *
* You should have received a copy of the GNU General Public License *
* along with this program; if not, write to the Free Software *
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. *
*******************************************************************************/
#include "StdAfx.h"
/**
* GenericDnsQueryCallback
*
* Used as a thunk between c-ares' C-style callbacks and shroudBNC's
* object-oriented dns class.
*
* @param Cookie a pointer to a CDnsQuery object
* @param Status the status of the dns query
* @param Timeout reports how many times a query timed out during the
* execution of the given request, useable for logging purpose.
* @param HostEntity the response for the dns query (can be NULL)
*/
void GenericDnsQueryCallback(void *Cookie, int Status, int Timeout, hostent *HostEntity) {
CDnsQuery *Query = (CDnsQuery *)Cookie;
Query->AsyncDnsEvent(Status, HostEntity);
Query->m_PendingQueries--;
}
/**
* CDnsQuery
*
* Constructs a new DNS query object.
*
* @param EventInterface an object to which DNS callbacks are routed
* @param EventFunction a function which is called when DNS queries are completed
* @param Timeout specifies the timeout value for dns queries
*
* \see IMPL_DNSEVENTPROXY
* \see USE_DNSEVENTPROXY
*/
CDnsQuery::CDnsQuery(void *EventInterface, DnsEventFunction EventFunction, int Timeout) {
m_Timeout = Timeout;
m_EventObject = EventInterface;
m_EventFunction = EventFunction;
m_Channel = NULL;
m_PendingQueries = 0;
FD_ZERO(&m_Reader);
FD_ZERO(&m_Writer);
}
/**
* InitChannel
*
* Initializes a new ARES channel.
*/
void CDnsQuery::InitChannel(void) {
if (m_Channel == NULL) {
ares_options Options;
Options.timeout = m_Timeout;
ares_init_options(&m_Channel, &Options, ARES_OPT_TIMEOUT);
g_Bouncer->RegisterDnsQuery(this);
}
}
/**
* DestroyChannel
*
* Destroys the ARES channel.
*/
void CDnsQuery::DestroyChannel(void) {
DnsEventFunction Function;
if (m_Channel != NULL) {
FD_ZERO(&m_Reader);
FD_ZERO(&m_Writer);
Function = m_EventFunction;
m_EventFunction = NULL;
ares_destroy(m_Channel);
m_EventFunction = Function;
m_Channel = NULL;
g_Bouncer->UnregisterDnsQuery(this);
m_PendingQueries = 0;
}
}
/**
* ~CDnsQuery
*
* Destructs a DNS query object.
*/
CDnsQuery::~CDnsQuery(void) {
DestroyChannel();
}
/**
* GetHostByName
*
* Asynchronously performs the task of the "gethostbyname" function
* and calls the callback function once the operation has completed.
*
* @param Host the hostname
* @param Family the address family (AF_INET or AF_INET6)
*/
void CDnsQuery::GetHostByName(const char *Host, int Family) {
InitChannel();
m_PendingQueries++;
ares_gethostbyname(m_Channel, Host, Family, GenericDnsQueryCallback, this);
}
/**
* GetHostByAddr
*
* Asynchronously performs the task of the "gethostbyaddr" function
* and calls the callback function once the operation has completed.
*
* @param Address the address for which the hostname should be looked up
*/
void CDnsQuery::GetHostByAddr(sockaddr *Address) {
void *IpAddr;
#ifdef IPV6
if (Address->sa_family == AF_INET) {
#endif
IpAddr = &(((sockaddr_in *)Address)->sin_addr);
#ifdef IPV6
} else {
IpAddr = &(((sockaddr_in6 *)Address)->sin6_addr);
}
#endif
InitChannel();
m_PendingQueries++;
ares_gethostbyaddr(m_Channel, IpAddr, INADDR_LEN(Address->sa_family), Address->sa_family, GenericDnsQueryCallback, this);
}
/**
* GetChannel
*
* Returns the underlying c-ares channel object.
*/
ares_channel CDnsQuery::GetChannel(void) {
return m_Channel;
}
/**
* AsyncDnsEvent
*
* Used by GenericDnsQueryCallback to notify the object of the status
* of a dns query.
*
* @param Status the status
* @param Response the response for the dns query
*/
void CDnsQuery::AsyncDnsEvent(int Status, hostent *Response) {
if (m_EventFunction != NULL) {
(*m_EventFunction)(m_EventObject, Response);
}
}
/**
* Cleanup
*
* Cleans up unused channels.
*/
void CDnsQuery::Cleanup(void) {
if (m_PendingQueries == 0) {
DestroyChannel();
}
}
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