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/*
dns.h - dns library declarations based on firedns Copyright (C) 2002 Ian Gulliver
This program is free software; you can redistribute it and/or modify
it under the terms of version 2 of the GNU General Public License as
published by the Free Software Foundation.
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
*/
#ifndef _DNS_H
#define _DNS_H
#include <string>
#include "inspircd_config.h"
#include "socket.h"
#include "base.h"
typedef std::pair<int,std::string> DNSResult;
typedef std::pair<unsigned char*, std::string> DNSInfo;
/**
* Error types that class Resolver can emit to its error method.
*/
enum ResolverError
{
RESOLVER_NOERROR = 0,
RESOLVER_NSDOWN = 1,
RESOLVER_NXDOMAIN = 2,
RESOLVER_NOTREADY = 3,
RESOLVER_BADIP = 4
};
class DNSRequest;
class DNSHeader;
/**
* The Resolver class is a high-level abstraction for resolving DNS entries.
* It can do forward and reverse IPv4 lookups, and where IPv6 is supported, will
* also be able to do those, transparent of protocols. Module developers must
* extend this class via inheritence, and then insert a pointer to their derived
* class into the core using Server::AddResolver(). Once you have done this,
* the class will be able to receive callbacks. There are two callbacks which
* can occur by calling virtual methods, one is a success situation, and the other
* an error situation.
*/
class Resolver : public Extensible
{
protected:
/**
* The input data, either a host or an IP address
*/
std::string input;
/**
* True if a forward lookup is being performed, false if otherwise
*/
bool fwd;
/**
* The DNS erver being used for lookups. If this is an empty string,
* the value of ServerConfig::DNSServer is used instead.
*/
std::string server;
/**
* The ID allocated to your lookup. This is a pseud-random number
* between 0 and 65535, a value of -1 indicating a failure.
* The core uses this to route results to the correct objects.
*/
int myid;
public:
/**
* Initiate DNS lookup. Your class should not attempt to delete or free these
* objects, as the core will do this for you. They must always be created upon
* the heap using new, as you cannot be sure at what time they will be deleted.
* Allocating them on the stack or attempting to delete them yourself could cause
* the object to go 'out of scope' and cause a segfault in the core if the result
* arrives at a later time.
* @param source The IP or hostname to resolve
* @param forward Set to true to perform a forward lookup (hostname to ip) or false
* to perform a reverse lookup (ip to hostname). Lookups on A records and PTR
* records are supported. CNAME and MX are not supported by this resolver.
* If InspIRCd is compiled with ipv6 support, lookups on AAAA records are preferred
* and supported over A records.
* @throw ModuleException This class may throw an instance of ModuleException, in the
* event a lookup could not be allocated, or a similar hard error occurs such as
* the network being down.
*/
Resolver(const std::string &source, bool forward);
/**
* The default destructor does nothing.
*/
virtual ~Resolver();
/**
* When your lookup completes, this method will be called.
* @param result The resulting DNS lookup, either an IP address or a hostname.
*/
virtual void OnLookupComplete(const std::string &result) = 0;
/**
* If an error occurs (such as NXDOMAIN, no domain name found) then this method
* will be called.
* @param e A ResolverError enum containing the error type which has occured.
* @param errormessage The error text of the error that occured.
*/
virtual void OnError(ResolverError e, const std::string &errormessage);
/**
* Returns the id value of this class. This is primarily used by the core
* to determine where in various tables to place a pointer to your class, but it
* is safe to call and use this method.
* As specified in RFC1035, each dns request has a 16 bit ID value, ranging
* from 0 to 65535. If there is an issue and the core cannot send your request,
* this method will return -1.
*/
int GetId();
};
/** DNS is a singleton class used by the core to dispatch dns
* requests to the dns server, and route incoming dns replies
* back to Resolver objects, based upon the request ID. You
* should never use this class yourself.
*/
class DNS : public Extensible
{
private:
insp_inaddr myserver;
public:
int GetIP(const char* name);
int GetName(const insp_inaddr* ip);
DNSResult GetResult();
void MarshallReads(int fd);
bool AddResolverClass(Resolver* r);
DNSRequest* DNSAddQuery(DNSHeader *header, int &id);
DNS();
~DNS();
};
#endif
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