-/* +------------------------------------+
- * | Inspire Internet Relay Chat Daemon |
- * +------------------------------------+
+/*
+ * InspIRCd -- Internet Relay Chat Daemon
+ *
+ * Copyright (C) 2009 Daniel De Graaf <danieldg@inspircd.org>
+ * Copyright (C) 2005-2008 Craig Edwards <craigedwards@brainbox.cc>
+ * Copyright (C) 2007 Dennis Friis <peavey@inspircd.org>
*
- * InspIRCd is copyright (C) 2002-2006 ChatSpike-Dev.
- * E-mail:
- * <brain@chatspike.net>
- * <Craig@chatspike.net>
+ * This file is part of InspIRCd. InspIRCd 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, version 2.
*
- * Written by Craig Edwards, Craig McLure, and others.
- * This program is free but copyrighted software; see
- * the file COPYING for details.
+ * 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, see <http://www.gnu.org/licenses/>.
*/
+
/*
dns.h - dns library very very loosely based on
firedns, Copyright (C) 2002 Ian Gulliver
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
-#ifndef _DNS_H
-#define _DNS_H
+#ifndef DNS_H
+#define DNS_H
-#include <string>
-#include "inspircd_config.h"
#include "socket.h"
-#include "base.h"
-
-/**
- * Result status, used internally
- */
-typedef std::pair<int,std::string> DNSResult;
+#include "hashcomp.h"
/**
- * Information on a completed lookup, used internally
+ * Query and resource record types
*/
-typedef std::pair<unsigned char*, std::string> DNSInfo;
+enum QueryType
+{
+ /** Uninitialized Query */
+ DNS_QUERY_NONE = 0,
+ /** 'A' record: an ipv4 address */
+ DNS_QUERY_A = 1,
+ /** 'CNAME' record: An alias */
+ DNS_QUERY_CNAME = 5,
+ /** 'PTR' record: a hostname */
+ DNS_QUERY_PTR = 12,
+ /** 'AAAA' record: an ipv6 address */
+ DNS_QUERY_AAAA = 28,
+
+ /** Force 'PTR' to use IPV4 scemantics */
+ DNS_QUERY_PTR4 = 0xFFFD,
+ /** Force 'PTR' to use IPV6 scemantics */
+ DNS_QUERY_PTR6 = 0xFFFE
+};
/**
- * Error types that class Resolver can emit to its error method.
+ * Result status, used internally
*/
-enum ResolverError
+class CoreExport DNSResult
{
- RESOLVER_NOERROR = 0,
- RESOLVER_NSDOWN = 1,
- RESOLVER_NXDOMAIN = 2,
- RESOLVER_NOTREADY = 3,
- RESOLVER_BADIP = 4
+ public:
+ /** Result ID
+ */
+ int id;
+ /** Result body, a hostname or IP address
+ */
+ std::string result;
+ /** Time-to-live value of the result
+ */
+ unsigned long ttl;
+ /** The original request, a hostname or IP address
+ */
+ std::string original;
+ /** The type of the request
+ */
+ QueryType type;
+
+ /** Build a DNS result.
+ * @param i The request ID
+ * @param res The request result, a hostname or IP
+ * @param timetolive The request time-to-live
+ * @param orig The original request, a hostname or IP
+ * @param qt The type of DNS query this result represents.
+ */
+ DNSResult(int i, const std::string &res, unsigned long timetolive, const std::string &orig, QueryType qt = DNS_QUERY_NONE) : id(i), result(res), ttl(timetolive), original(orig), type(qt) { }
};
/**
- * A DNS request
+ * Information on a completed lookup, used internally
*/
-class DNSRequest;
+typedef std::pair<unsigned char*, std::string> DNSInfo;
-/**
- * A DNS packet header
+/** Cached item stored in the query cache.
*/
-class DNSHeader;
+class CoreExport CachedQuery
+{
+ public:
+ /** The cached result data, an IP or hostname
+ */
+ std::string data;
+ /** The type of result this is
+ */
+ QueryType type;
+ /** The time when the item is due to expire
+ */
+ time_t expires;
-/**
- * A DNS Resource Record (rr)
- */
-class ResourceRecord;
+ /** Build a cached query
+ * @param res The result data, an IP or hostname
+ * @param qt The type of DNS query this instance represents.
+ * @param ttl The time-to-live value of the query result
+ */
+ CachedQuery(const std::string &res, QueryType qt, unsigned int ttl);
-/**
- * A set of requests keyed by request id
- */
-typedef std::map<int,DNSRequest*> requestlist;
+ /** Returns the number of seconds remaining before this
+ * cache item has expired and should be removed.
+ */
+ int CalcTTLRemaining();
+};
-/**
- * An iterator into a set of requests
+/** DNS cache information. Holds IPs mapped to hostnames, and hostnames mapped to IPs.
*/
-typedef requestlist::iterator requestlist_iter;
+typedef nspace::hash_map<irc::string, CachedQuery, irc::hash> dnscache;
/**
- * Query and resource record types
+ * Error types that class Resolver can emit to its error method.
*/
-enum QueryType
+enum ResolverError
{
- DNS_QUERY_A = 1, /* 'A' record: an ipv4 address */
- DNS_QUERY_CNAME = 5, /* 'CNAME' record: An alias */
- DNS_QUERY_PTR = 12, /* 'PTR' record: a hostname */
- DNS_QUERY_AAAA = 28, /* 'AAAA' record: an ipv6 address */
-
- DNS_QUERY_PTR4 = 0xFFFD, /* Force 'PTR' to use IPV4 scemantics */
- DNS_QUERY_PTR6 = 0xFFFE, /* Force 'PTR' to use IPV6 scemantics */
+ RESOLVER_NOERROR = 0,
+ RESOLVER_NSDOWN = 1,
+ RESOLVER_NXDOMAIN = 2,
+ RESOLVER_BADIP = 3,
+ RESOLVER_TIMEOUT = 4,
+ RESOLVER_FORCEUNLOAD = 5
};
-#ifdef IPV6
-const QueryType DNS_QUERY_FORWARD = DNS_QUERY_AAAA;
-const QueryType DNS_QUERY_REVERSE = DNS_QUERY_PTR;
-#else
-const QueryType DNS_QUERY_FORWARD = DNS_QUERY_A;
-const QueryType DNS_QUERY_REVERSE = DNS_QUERY_PTR;
-#endif
-
/**
* Used internally to force PTR lookups to use a certain protocol scemantics,
* e.g. x.x.x.x.in-addr.arpa for v4, and *.ip6.arpa for v6.
*/
enum ForceProtocol
{
- PROTOCOL_IPV4 = 0, /* Forced to use ipv4 */
- PROTOCOL_IPV6 = 1 /* Forced to use ipv6 */
+ /** Forced to use ipv4 */
+ PROTOCOL_IPV4 = 0,
+ /** Forced to use ipv6 */
+ PROTOCOL_IPV6 = 1
};
/**
* can occur by calling virtual methods, one is a success situation, and the other
* an error situation.
*/
-class Resolver : public Extensible
+class CoreExport Resolver
{
protected:
+ /**
+ * Pointer to creator module (if any, or NULL)
+ */
+ ModuleRef Creator;
/**
* The input data, either a host or an IP address
*/
* The core uses this to route results to the correct objects.
*/
int myid;
+
+ /**
+ * Cached result, if there is one
+ */
+ CachedQuery *CQ;
+
+ /**
+ * Time left before cache expiry
+ */
+ int time_left;
+
public:
/**
* Initiate DNS lookup. Your class should not attempt to delete or free these
* 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 qt The query type to perform. If you just want to perform a forward
- * or reverse lookup, and you don't care wether you get ipv4 or ipv6, then use
- * the constants DNS_QUERY_FORWARD and DNS_QUERY_REVERSE, which automatically
- * select from 'A' record or 'AAAA' record lookups. However, if you want to resolve
- * a specific record type, resolution of 'A', 'AAAA', 'PTR' and 'CNAME' records
+ * @param qt The query type to perform. Resolution of 'A', 'AAAA', 'PTR' and 'CNAME' records
* is supported. Use one of the QueryType enum values to initiate this type of
* lookup. Resolution of 'AAAA' ipv6 records is always supported, regardless of
* wether InspIRCd is built with ipv6 support.
- * If you attempt to resolve a 'PTR' record using DNS_QUERY_PTR, and InspIRCd is
- * built with ipv6 support, the 'PTR' record will be formatted to ipv6 specs,
- * e.g. x.x.x.x.x....ip6.arpa. otherwise it will be formatted to ipv4 specs,
- * e.g. x.x.x.x.in-addr.arpa. This translation is automatic.
- * To get around this automatic behaviour, you must use one of the values
- * DNS_QUERY_PTR4 or DNS_QUERY_PTR6 to force ipv4 or ipv6 behaviour on the lookup,
- * irrespective of what protocol InspIRCd has been built for.
+ * To look up reverse records, specify one of DNS_QUERY_PTR4 or DNS_QUERY_PTR6 depending
+ * on the type of address you are looking up.
+ * @param cached The constructor will set this boolean to true or false depending
+ * on whether the DNS lookup you are attempting is cached (and not expired) or not.
+ * If the value is cached, upon return this will be set to true, otherwise it will
+ * be set to false. You should pass this value to InspIRCd::AddResolver(), which
+ * will then influence the behaviour of the method and determine whether a cached
+ * or non-cached result is obtained. The value in this variable is always correct
+ * for the given request when the constructor exits.
+ * @param creator See the note below.
* @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. This will also be thrown if an invalid IP address is
* passed when resolving a 'PTR' record.
+ *
+ * NOTE: If you are instantiating your DNS lookup from a module, you should set the
+ * value of creator to point at your Module class. This way if your module is unloaded
+ * whilst lookups are in progress, they can be safely removed and your module will not
+ * crash the server.
*/
- Resolver(const std::string &source, QueryType qt);
+ Resolver(const std::string &source, QueryType qt, bool &cached, Module* creator);
+
/**
* 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.
+ * @param ttl The time-to-live value of the result, in the instance of a cached
+ * result, this is the number of seconds remaining before refresh/expiry.
+ * @param cached True if the result is a cached result, false if it was requested
+ * from the DNS server.
*/
- virtual void OnLookupComplete(const std::string &result) = 0;
+ virtual void OnLookupComplete(const std::string &result, unsigned int ttl, bool cached) = 0;
+
/**
* If an error occurs (such as NXDOMAIN, no domain name found) then this method
* will be called.
* @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
* this method will return -1.
*/
int GetId();
+
+ /**
+ * Returns the creator module, or NULL
+ */
+ Module* GetCreator();
+
+ /**
+ * If the result is a cached result, this triggers the objects
+ * OnLookupComplete. This is done because it is not safe to call
+ * the abstract virtual method from the constructor.
+ */
+ void TriggerCachedResult();
};
/** DNS is a singleton class used by the core to dispatch dns
* back to Resolver objects, based upon the request ID. You
* should never use this class yourself.
*/
-class DNS : public Extensible
+class CoreExport DNS : public EventHandler
{
private:
*/
static const int MAX_REQUEST_ID = 0xFFFF;
- /**
- * Requests that are currently 'in flight'
+ /** Maximum number of entries in cache
*/
- requestlist requests;
+ static const unsigned int MAX_CACHE_SIZE = 1000;
/**
- * Server address being used currently
+ * Currently cached items
*/
- insp_inaddr myserver;
+ dnscache* cache;
- /**
- * File descriptor being used to perform queries
+ /** A timer which ticks every hour to remove expired
+ * items from the DNS cache.
*/
- static int MasterSocket;
+ class CacheTimer* PruneTimer;
/**
- * A counter used to form part of the pseudo-random id
+ * Build a dns packet payload
*/
- int currid;
+ int MakePayload(const char* name, const QueryType rr, const unsigned short rr_class, unsigned char* payload);
+
+ public:
+
+ irc::sockets::sockaddrs myserver;
/**
* Currently active Resolver classes
Resolver* Classes[MAX_REQUEST_ID];
/**
- * Build a dns packet payload
+ * Requests that are currently 'in flight'
*/
- int MakePayload(const char* name, const QueryType rr, const unsigned short rr_class, unsigned char* payload);
+ DNSRequest* requests[MAX_REQUEST_ID];
- public:
/**
* The port number DNS requests are made on,
* and replies have as a source-port number.
* Fill an rr (resource record) with data from input
*/
static void FillResourceRecord(ResourceRecord* rr, const unsigned char* input);
+
/**
* Fill a header with data from input limited by a length
*/
static void FillHeader(DNSHeader *header, const unsigned char *input, const int length);
+
/**
* Empty out a header into a data stream ready for transmission "on the wire"
*/
static void EmptyHeader(unsigned char *output, const DNSHeader *header, const int length);
- /**
- * Get the master socket fd, used internally
- */
- static int GetMasterSocket();
/**
* Start the lookup of an ipv4 from a hostname
*/
int GetIP(const char* name);
- /**
- * Start the lookup of a hostname from an ip,
- * always using the protocol inspircd is built for,
- * e.g. use ipv6 reverse lookup when built for ipv6,
- * or ipv4 lookup when built for ipv4.
- */
- int GetName(const insp_inaddr* ip);
-
/**
* Start lookup of a hostname from an ip, but
* force a specific protocol to be used for the lookup
/**
* Handle a SocketEngine read event
+ * Inherited from EventHandler
*/
- void MarshallReads(int fd);
+ void HandleEvent(EventType et, int errornum = 0);
/**
* Add a Resolver* to the list of active classes
/**
* Add a query to the list to be sent
*/
- DNSRequest* AddQuery(DNSHeader *header, int &id);
+ DNSRequest* AddQuery(DNSHeader *header, int &id, const char* original);
/**
* The constructor initialises the dns socket,
DNS();
/**
- * Destructor
+ * Re-initialize the DNS subsystem.
*/
- ~DNS();
+ void Rehash();
- /** Portable random number generator, generates
- * its random number from the ircd stats counters,
- * effective user id, time of day and the rollover
- * counter (currid)
+ /**
+ * Destructor
*/
- unsigned long PRNG();
+ ~DNS();
/**
* Turn an in6_addr into a .ip6.arpa domain
*/
static void MakeIP6Int(char* query, const in6_addr *ip);
+
+ /**
+ * Clean out all dns resolvers owned by a particular
+ * module, to make unloading a module safe if there
+ * are dns requests currently in progress.
+ */
+ void CleanResolvers(Module* module);
+
+ /** Return the cached value of an IP or hostname
+ * @param source An IP or hostname to find in the cache.
+ * @return A pointer to a CachedQuery if the item exists,
+ * otherwise NULL.
+ */
+ CachedQuery* GetCache(const std::string &source);
+
+ /** Delete a cached item from the DNS cache.
+ * @param source An IP or hostname to remove
+ */
+ void DelCache(const std::string &source);
+
+ /** Clear all items from the DNS cache immediately.
+ */
+ int ClearCache();
+
+ /** Prune the DNS cache, e.g. remove all expired
+ * items and rehash the cache buckets, but leave
+ * items in the hash which are still valid.
+ */
+ int PruneCache();
};
#endif
projects / user / henk / code / inspircd.git / blobdiff