-/* +------------------------------------+\r * | Inspire Internet Relay Chat Daemon |\r * +------------------------------------+\r *\r * InspIRCd: (C) 2002-2007 InspIRCd Development Team\r * See: http://www.inspircd.org/wiki/index.php/Credits\r *\r * This program is free but copyrighted software; see\r * the file COPYING for details.\r *\r * ---------------------------------------------------\r */\r\r/*\rdns.h - dns library very very loosely based on\rfiredns, Copyright (C) 2002 Ian Gulliver\r\rThis program is free software; you can redistribute it and/or modify\rit under the terms of version 2 of the GNU General Public License as\rpublished by the Free Software Foundation.\r\rThis program is distributed in the hope that it will be useful,\rbut WITHOUT ANY WARRANTY; without even the implied warranty of\rMERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the\rGNU General Public License for more details.\r\rYou should have received a copy of the GNU General Public License\ralong with this program; if not, write to the Free Software\rFoundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA\r*/\r\r#ifndef _DNS_H\r#define _DNS_H\r\r#include <string>\r#include "inspircd_config.h"\r#include "base.h"\r#include "socketengine.h"\r#include "socket.h"\r#include "hash_map.h"\r#include "hashcomp.h"\r\rusing namespace std;\rusing irc::sockets::insp_aton;\rusing irc::sockets::insp_ntoa;\rusing irc::sockets::insp_sockaddr;\rusing irc::sockets::insp_inaddr;\r\rclass InspIRCd;\rclass Module;\r\r/**\r * Result status, used internally\r */\rclass CoreExport DNSResult : public classbase\r{\r public:\r /** Result ID\r */\r int id;\r /** Result body, a hostname or IP address\r */\r std::string result;\r /** Time-to-live value of the result\r */\r unsigned long ttl;\r /** The original request, a hostname or IP address\r */\r std::string original;\r\r /** Build a DNS result.\r * @param i The request ID\r * @param res The request result, a hostname or IP\r * @param timetolive The request time-to-live\r * @param orig The original request, a hostname or IP\r */\r DNSResult(int i, const std::string &res, unsigned long timetolive, const std::string &orig) : id(i), result(res), ttl(timetolive), original(orig) { }\r};\r\r/**\r * Information on a completed lookup, used internally\r */\rtypedef std::pair<unsigned char*, std::string> DNSInfo;\r\r/** Cached item stored in the query cache.\r */\rclass CoreExport CachedQuery\r{\r public:\r /** The cached result data, an IP or hostname\r */\r std::string data;\r /** The time when the item is due to expire\r */\r time_t expires;\r\r /** Build a cached query\r * @param res The result data, an IP or hostname\r * @param ttl The time-to-live value of the query result\r */\r CachedQuery(const std::string &res, unsigned int ttl) : data(res)\r {\r expires = time(NULL) + ttl;\r }\r\r /** Returns the number of seconds remaining before this\r * cache item has expired and should be removed.\r */\r int CalcTTLRemaining()\r {\r int n = (int)expires - (int)time(NULL);\r return (n < 0 ? 0 : n);\r }\r};\r\r/** DNS cache information. Holds IPs mapped to hostnames, and hostnames mapped to IPs.\r */\r#ifndef WIN32\rtypedef nspace::hash_map<irc::string, CachedQuery, nspace::hash<irc::string> > dnscache;\r#else\rtypedef nspace::hash_map<irc::string, CachedQuery, nspace::hash_compare<irc::string> > dnscache;\r#endif\r\r/**\r * Error types that class Resolver can emit to its error method.\r */\renum ResolverError\r{\r RESOLVER_NOERROR = 0,\r RESOLVER_NSDOWN = 1,\r RESOLVER_NXDOMAIN = 2,\r RESOLVER_NOTREADY = 3,\r RESOLVER_BADIP = 4,\r RESOLVER_TIMEOUT = 5,\r RESLOVER_FORCEUNLOAD = 6\r};\r\r/**\r * A DNS request\r */\rclass DNSRequest;\r\r/**\r * A DNS packet header\r */\rclass DNSHeader;\r\r/**\r * A DNS Resource Record (rr)\r */\rstruct ResourceRecord;\r\r/**\r * Query and resource record types\r */\renum QueryType\r{\r DNS_QUERY_NONE = 0, /* Uninitialized Query */\r DNS_QUERY_A = 1, /* 'A' record: an ipv4 address */\r DNS_QUERY_CNAME = 5, /* 'CNAME' record: An alias */\r DNS_QUERY_PTR = 12, /* 'PTR' record: a hostname */\r DNS_QUERY_AAAA = 28, /* 'AAAA' record: an ipv6 address */\r\r DNS_QUERY_PTR4 = 0xFFFD, /* Force 'PTR' to use IPV4 scemantics */\r DNS_QUERY_PTR6 = 0xFFFE /* Force 'PTR' to use IPV6 scemantics */\r};\r\r#ifdef IPV6\rconst QueryType DNS_QUERY_FORWARD = DNS_QUERY_AAAA;\r#else\rconst QueryType DNS_QUERY_FORWARD = DNS_QUERY_A;\r#endif\rconst QueryType DNS_QUERY_REVERSE = DNS_QUERY_PTR;\r/**\r * Used internally to force PTR lookups to use a certain protocol scemantics,\r * e.g. x.x.x.x.in-addr.arpa for v4, and *.ip6.arpa for v6.\r */\renum ForceProtocol\r{\r PROTOCOL_IPV4 = 0, /* Forced to use ipv4 */\r PROTOCOL_IPV6 = 1 /* Forced to use ipv6 */\r};\r\r/**\r * The Resolver class is a high-level abstraction for resolving DNS entries.\r * It can do forward and reverse IPv4 lookups, and where IPv6 is supported, will\r * also be able to do those, transparent of protocols. Module developers must\r * extend this class via inheritence, and then insert a pointer to their derived\r * class into the core using Server::AddResolver(). Once you have done this,\r * the class will be able to receive callbacks. There are two callbacks which\r * can occur by calling virtual methods, one is a success situation, and the other\r * an error situation.\r */\rclass CoreExport Resolver : public Extensible\r{\r protected:\r /**\r * Pointer to creator\r */\r InspIRCd* ServerInstance;\r /**\r * Pointer to creator module (if any, or NULL)\r */\r Module* Creator;\r /**\r * The input data, either a host or an IP address\r */\r std::string input;\r /**\r * True if a forward lookup is being performed, false if otherwise\r */\r QueryType querytype;\r /**\r * The DNS erver being used for lookups. If this is an empty string,\r * the value of ServerConfig::DNSServer is used instead.\r */\r std::string server;\r /**\r * The ID allocated to your lookup. This is a pseudo-random number\r * between 0 and 65535, a value of -1 indicating a failure.\r * The core uses this to route results to the correct objects.\r */\r int myid;\r\r /**\r * Cached result, if there is one\r */\r CachedQuery *CQ;\r\r /**\r * Time left before cache expiry\r */\r int time_left;\r public:\r /**\r * Initiate DNS lookup. Your class should not attempt to delete or free these\r * objects, as the core will do this for you. They must always be created upon\r * the heap using new, as you cannot be sure at what time they will be deleted.\r * Allocating them on the stack or attempting to delete them yourself could cause\r * the object to go 'out of scope' and cause a segfault in the core if the result\r * arrives at a later time.\r * @param source The IP or hostname to resolve\r * @param qt The query type to perform. If you just want to perform a forward\r * or reverse lookup, and you don't care wether you get ipv4 or ipv6, then use\r * the constants DNS_QUERY_FORWARD and DNS_QUERY_REVERSE, which automatically\r * select from 'A' record or 'AAAA' record lookups. However, if you want to resolve\r * a specific record type, resolution of 'A', 'AAAA', 'PTR' and 'CNAME' records\r * is supported. Use one of the QueryType enum values to initiate this type of\r * lookup. Resolution of 'AAAA' ipv6 records is always supported, regardless of\r * wether InspIRCd is built with ipv6 support.\r * If you attempt to resolve a 'PTR' record using DNS_QUERY_PTR, and InspIRCd is\r * built with ipv6 support, the 'PTR' record will be formatted to ipv6 specs,\r * e.g. x.x.x.x.x....ip6.arpa. otherwise it will be formatted to ipv4 specs,\r * e.g. x.x.x.x.in-addr.arpa. This translation is automatic.\r * To get around this automatic behaviour, you must use one of the values\r * DNS_QUERY_PTR4 or DNS_QUERY_PTR6 to force ipv4 or ipv6 behaviour on the lookup,\r * irrespective of what protocol InspIRCd has been built for.\r * @param cached The constructor will set this boolean to true or false depending\r * on whether the DNS lookup you are attempting is cached (and not expired) or not.\r * If the value is cached, upon return this will be set to true, otherwise it will\r * be set to false. You should pass this value to InspIRCd::AddResolver(), which\r * will then influence the behaviour of the method and determine whether a cached\r * or non-cached result is obtained. The value in this variable is always correct\r * for the given request when the constructor exits.\r * @param creator See the note below.\r * @throw ModuleException This class may throw an instance of ModuleException, in the\r * event a lookup could not be allocated, or a similar hard error occurs such as\r * the network being down. This will also be thrown if an invalid IP address is\r * passed when resolving a 'PTR' record.\r *\r * NOTE: If you are instantiating your DNS lookup from a module, you should set the\r * value of creator to point at your Module class. This way if your module is unloaded\r * whilst lookups are in progress, they can be safely removed and your module will not\r * crash the server.\r */\r Resolver(InspIRCd* Instance, const std::string &source, QueryType qt, bool &cached, Module* creator = NULL);\r\r /**\r * The default destructor does nothing.\r */\r virtual ~Resolver();\r /**\r * When your lookup completes, this method will be called.\r * @param result The resulting DNS lookup, either an IP address or a hostname.\r * @param ttl The time-to-live value of the result, in the instance of a cached\r * result, this is the number of seconds remaining before refresh/expiry.\r * @param cached True if the result is a cached result, false if it was requested\r * from the DNS server.\r */\r virtual void OnLookupComplete(const std::string &result, unsigned int ttl, bool cached) = 0;\r /**\r * If an error occurs (such as NXDOMAIN, no domain name found) then this method\r * will be called.\r * @param e A ResolverError enum containing the error type which has occured.\r * @param errormessage The error text of the error that occured.\r */\r virtual void OnError(ResolverError e, const std::string &errormessage);\r /**\r * Returns the id value of this class. This is primarily used by the core\r * to determine where in various tables to place a pointer to your class, but it\r * is safe to call and use this method.\r * As specified in RFC1035, each dns request has a 16 bit ID value, ranging\r * from 0 to 65535. If there is an issue and the core cannot send your request,\r * this method will return -1.\r */\r int GetId();\r /**\r * Returns the creator module, or NULL\r */\r Module* GetCreator();\r /**\r * If the result is a cached result, this triggers the objects\r * OnLookupComplete. This is done because it is not safe to call\r * the abstract virtual method from the constructor.\r */\r void TriggerCachedResult();\r};\r\r/** DNS is a singleton class used by the core to dispatch dns\r * requests to the dns server, and route incoming dns replies\r * back to Resolver objects, based upon the request ID. You\r * should never use this class yourself.\r */\rclass CoreExport DNS : public EventHandler\r{\r private:\r\r /**\r * Creator/Owner object\r */\r InspIRCd* ServerInstance;\r\r /**\r * The maximum value of a dns request id,\r * 16 bits wide, 0xFFFF.\r */\r static const int MAX_REQUEST_ID = 0xFFFF;\r\r /**\r * A counter used to form part of the pseudo-random id\r */\r int currid;\r\r /**\r * We have to turn off a few checks on received packets\r * when people are using 4in6 (e.g. ::ffff:xxxx). This is\r * a temporary kludge, Please let me know if you know how\r * to fix it.\r */\r bool ip6munge;\r\r /**\r * Currently cached items\r */\r dnscache* cache;\r\r /** A timer which ticks every hour to remove expired\r * items from the DNS cache.\r */\r class CacheTimer* PruneTimer;\r\r /**\r * Build a dns packet payload\r */\r int MakePayload(const char* name, const QueryType rr, const unsigned short rr_class, unsigned char* payload);\r\r public:\r\r /**\r * Server address being used currently\r */\r int socketfamily;\r#ifdef IPV6\r in6_addr myserver6;\r#endif\r in_addr myserver4;\r\r /**\r * Currently active Resolver classes\r */\r Resolver* Classes[MAX_REQUEST_ID];\r\r /**\r * Requests that are currently 'in flight'\r */\r DNSRequest* requests[MAX_REQUEST_ID];\r\r /**\r * The port number DNS requests are made on,\r * and replies have as a source-port number.\r */\r static const int QUERY_PORT = 53;\r\r /**\r * Fill an rr (resource record) with data from input\r */\r static void FillResourceRecord(ResourceRecord* rr, const unsigned char* input);\r\r /**\r * Fill a header with data from input limited by a length\r */\r static void FillHeader(DNSHeader *header, const unsigned char *input, const int length);\r\r /**\r * Empty out a header into a data stream ready for transmission "on the wire"\r */\r static void EmptyHeader(unsigned char *output, const DNSHeader *header, const int length);\r\r /**\r * Start the lookup of an ipv4 from a hostname\r */\r int GetIP(const char* name);\r\r /**\r * Start the lookup of a hostname from an ip,\r * always using the protocol inspircd is built for,\r * e.g. use ipv6 reverse lookup when built for ipv6,\r * or ipv4 lookup when built for ipv4.\r */\r int GetName(const insp_inaddr* ip);\r\r /**\r * Start lookup of a hostname from an ip, but\r * force a specific protocol to be used for the lookup\r * for example to perform an ipv6 reverse lookup.\r */\r int GetNameForce(const char *ip, ForceProtocol fp);\r\r /**\r * Start lookup of an ipv6 from a hostname\r */\r int GetIP6(const char *name);\r\r /**\r * Start lookup of a CNAME from another hostname\r */\r int GetCName(const char* alias);\r\r /**\r * Fetch the result string (an ip or host)\r * and/or an error message to go with it.\r */\r DNSResult GetResult();\r\r /**\r * Handle a SocketEngine read event\r * Inherited from EventHandler\r */\r void HandleEvent(EventType et, int errornum = 0);\r\r /**\r * Add a Resolver* to the list of active classes\r */\r bool AddResolverClass(Resolver* r);\r\r /**\r * Add a query to the list to be sent\r */\r DNSRequest* AddQuery(DNSHeader *header, int &id, const char* original);\r\r /**\r * The constructor initialises the dns socket,\r * and clears the request lists.\r */\r DNS(InspIRCd* Instance);\r\r /**\r * Re-initialize the DNS subsystem.\r */\r void Rehash();\r\r /**\r * Destructor\r */\r ~DNS();\r\r /** Portable random number generator, generates\r * its random number from the ircd stats counters,\r * effective user id, time of day and the rollover\r * counter (currid)\r */\r unsigned long PRNG();\r\r /**\r * Turn an in6_addr into a .ip6.arpa domain\r */\r static void MakeIP6Int(char* query, const in6_addr *ip);\r\r /**\r * Clean out all dns resolvers owned by a particular\r * module, to make unloading a module safe if there\r * are dns requests currently in progress.\r */\r void CleanResolvers(Module* module);\r\r /** Return the cached value of an IP or hostname\r * @param source An IP or hostname to find in the cache.\r * @return A pointer to a CachedQuery if the item exists,\r * otherwise NULL.\r */\r CachedQuery* GetCache(const std::string &source);\r\r /** Delete a cached item from the DNS cache.\r * @param source An IP or hostname to remove\r */\r void DelCache(const std::string &source);\r\r /** Clear all items from the DNS cache immediately.\r */\r int ClearCache();\r\r /** Prune the DNS cache, e.g. remove all expired\r * items and rehash the cache buckets, but leave\r * items in the hash which are still valid.\r */\r int PruneCache();\r};\r\r#endif\r\r
\ No newline at end of file
+/* +------------------------------------+
+ * | Inspire Internet Relay Chat Daemon |
+ * +------------------------------------+
+ *
+ * InspIRCd: (C) 2002-2007 InspIRCd Development Team
+ * See: http://www.inspircd.org/wiki/index.php/Credits
+ *
+ * This program is free but copyrighted software; see
+ * the file COPYING for details.
+ *
+ * ---------------------------------------------------
+ */
+
+/*
+dns.h - dns library very very loosely 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 "base.h"
+#include "socketengine.h"
+#include "socket.h"
+#include "hash_map.h"
+#include "hashcomp.h"
+
+using namespace std;
+using irc::sockets::insp_aton;
+using irc::sockets::insp_ntoa;
+using irc::sockets::insp_sockaddr;
+using irc::sockets::insp_inaddr;
+
+class InspIRCd;
+class Module;
+
+/**
+ * Result status, used internally
+ */
+class CoreExport DNSResult : public classbase
+{
+ 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;
+
+ /** 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
+ */
+ DNSResult(int i, const std::string &res, unsigned long timetolive, const std::string &orig) : id(i), result(res), ttl(timetolive), original(orig) { }
+};
+
+/**
+ * Information on a completed lookup, used internally
+ */
+typedef std::pair<unsigned char*, std::string> DNSInfo;
+
+/** Cached item stored in the query cache.
+ */
+class CoreExport CachedQuery
+{
+ public:
+ /** The cached result data, an IP or hostname
+ */
+ std::string data;
+ /** The time when the item is due to expire
+ */
+ time_t expires;
+
+ /** Build a cached query
+ * @param res The result data, an IP or hostname
+ * @param ttl The time-to-live value of the query result
+ */
+ CachedQuery(const std::string &res, unsigned int ttl) : data(res)
+ {
+ expires = time(NULL) + ttl;
+ }
+
+ /** Returns the number of seconds remaining before this
+ * cache item has expired and should be removed.
+ */
+ int CalcTTLRemaining()
+ {
+ int n = (int)expires - (int)time(NULL);
+ return (n < 0 ? 0 : n);
+ }
+};
+
+/** DNS cache information. Holds IPs mapped to hostnames, and hostnames mapped to IPs.
+ */
+#ifndef WIN32
+typedef nspace::hash_map<irc::string, CachedQuery, nspace::hash<irc::string> > dnscache;
+#else
+typedef nspace::hash_map<irc::string, CachedQuery, nspace::hash_compare<irc::string> > dnscache;
+#endif
+
+/**
+ * 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,
+ RESOLVER_TIMEOUT = 5,
+ RESLOVER_FORCEUNLOAD = 6
+};
+
+/**
+ * A DNS request
+ */
+class DNSRequest;
+
+/**
+ * A DNS packet header
+ */
+class DNSHeader;
+
+/**
+ * A DNS Resource Record (rr)
+ */
+struct ResourceRecord;
+
+/**
+ * Query and resource record types
+ */
+enum QueryType
+{
+ DNS_QUERY_NONE = 0, /* Uninitialized Query */
+ 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 */
+};
+
+#ifdef IPV6
+const QueryType DNS_QUERY_FORWARD = DNS_QUERY_AAAA;
+#else
+const QueryType DNS_QUERY_FORWARD = DNS_QUERY_A;
+#endif
+const QueryType DNS_QUERY_REVERSE = DNS_QUERY_PTR;
+/**
+ * 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 */
+};
+
+/**
+ * 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 CoreExport Resolver : public Extensible
+{
+ protected:
+ /**
+ * Pointer to creator
+ */
+ InspIRCd* ServerInstance;
+ /**
+ * Pointer to creator module (if any, or NULL)
+ */
+ Module* Creator;
+ /**
+ * The input data, either a host or an IP address
+ */
+ std::string input;
+ /**
+ * True if a forward lookup is being performed, false if otherwise
+ */
+ QueryType querytype;
+ /**
+ * 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 pseudo-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;
+
+ /**
+ * 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
+ * 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 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
+ * 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.
+ * @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(InspIRCd* Instance, const std::string &source, QueryType qt, bool &cached, Module* creator = NULL);
+
+ /**
+ * 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, unsigned int ttl, bool cached) = 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();
+ /**
+ * 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
+ * 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 CoreExport DNS : public EventHandler
+{
+ private:
+
+ /**
+ * Creator/Owner object
+ */
+ InspIRCd* ServerInstance;
+
+ /**
+ * The maximum value of a dns request id,
+ * 16 bits wide, 0xFFFF.
+ */
+ static const int MAX_REQUEST_ID = 0xFFFF;
+
+ /**
+ * A counter used to form part of the pseudo-random id
+ */
+ int currid;
+
+ /**
+ * We have to turn off a few checks on received packets
+ * when people are using 4in6 (e.g. ::ffff:xxxx). This is
+ * a temporary kludge, Please let me know if you know how
+ * to fix it.
+ */
+ bool ip6munge;
+
+ /**
+ * Currently cached items
+ */
+ dnscache* cache;
+
+ /** A timer which ticks every hour to remove expired
+ * items from the DNS cache.
+ */
+ class CacheTimer* PruneTimer;
+
+ /**
+ * Build a dns packet payload
+ */
+ int MakePayload(const char* name, const QueryType rr, const unsigned short rr_class, unsigned char* payload);
+
+ public:
+
+ /**
+ * Server address being used currently
+ */
+ int socketfamily;
+#ifdef IPV6
+ in6_addr myserver6;
+#endif
+ in_addr myserver4;
+
+ /**
+ * Currently active Resolver classes
+ */
+ Resolver* Classes[MAX_REQUEST_ID];
+
+ /**
+ * Requests that are currently 'in flight'
+ */
+ DNSRequest* requests[MAX_REQUEST_ID];
+
+ /**
+ * The port number DNS requests are made on,
+ * and replies have as a source-port number.
+ */
+ static const int QUERY_PORT = 53;
+
+ /**
+ * 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);
+
+ /**
+ * 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
+ * for example to perform an ipv6 reverse lookup.
+ */
+ int GetNameForce(const char *ip, ForceProtocol fp);
+
+ /**
+ * Start lookup of an ipv6 from a hostname
+ */
+ int GetIP6(const char *name);
+
+ /**
+ * Start lookup of a CNAME from another hostname
+ */
+ int GetCName(const char* alias);
+
+ /**
+ * Fetch the result string (an ip or host)
+ * and/or an error message to go with it.
+ */
+ DNSResult GetResult();
+
+ /**
+ * Handle a SocketEngine read event
+ * Inherited from EventHandler
+ */
+ void HandleEvent(EventType et, int errornum = 0);
+
+ /**
+ * Add a Resolver* to the list of active classes
+ */
+ bool AddResolverClass(Resolver* r);
+
+ /**
+ * Add a query to the list to be sent
+ */
+ DNSRequest* AddQuery(DNSHeader *header, int &id, const char* original);
+
+ /**
+ * The constructor initialises the dns socket,
+ * and clears the request lists.
+ */
+ DNS(InspIRCd* Instance);
+
+ /**
+ * Re-initialize the DNS subsystem.
+ */
+ void Rehash();
+
+ /**
+ * Destructor
+ */
+ ~DNS();
+
+ /** Portable random number generator, generates
+ * its random number from the ircd stats counters,
+ * effective user id, time of day and the rollover
+ * counter (currid)
+ */
+ unsigned long PRNG();
+
+ /**
+ * 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