* | Inspire Internet Relay Chat Daemon |
* +------------------------------------+
*
- * InspIRCd is copyright (C) 2002-2006 ChatSpike-Dev.
- * E-mail:
- * <brain@chatspike.net>
- * <Craig@chatspike.net>
+ * InspIRCd: (C) 2002-2007 InspIRCd Development Team
+ * See: http://www.inspircd.org/wiki/index.php/Credits
*
- * Written by Craig Edwards, Craig McLure, and others.
* This program is free but copyrighted software; see
- * the file COPYING for details.
+ * the file COPYING for details.
*
* ---------------------------------------------------
*/
#include <string>
#include "inspircd_config.h"
-#include "socket.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
*/
-typedef std::pair<int,std::string> DNSResult;
+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.
*/
RESOLVER_NSDOWN = 1,
RESOLVER_NXDOMAIN = 2,
RESOLVER_NOTREADY = 3,
- RESOLVER_BADIP = 4
+ RESOLVER_BADIP = 4,
+ RESOLVER_TIMEOUT = 5,
+ RESLOVER_FORCEUNLOAD = 6
};
/**
/**
* A DNS Resource Record (rr)
*/
-class ResourceRecord;
+struct ResourceRecord;
/**
- * A set of requests keyed by request id
+ * Query and resource record types
*/
-typedef std::map<int,DNSRequest*> requestlist;
+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;
/**
- * An iterator into a set of requests
+ * 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.
*/
-typedef requestlist::iterator requestlist_iter;
+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.
* can occur by calling virtual methods, one is a success situation, and the other
* an error situation.
*/
-class Resolver : public Extensible
+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
*/
/**
* True if a forward lookup is being performed, false if otherwise
*/
- bool fwd;
+ QueryType querytype;
/**
* The DNS erver being used for lookups. If this is an empty string,
* the value of ServerConfig::DNSServer is used instead.
* 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 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.
+ * @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.
+ * 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, bool forward);
+ Resolver(InspIRCd* Instance, const std::string &source, QueryType qt, bool &cached, Module* creator = NULL);
+
/**
* The default destructor does nothing.
*/
/**
* 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.
+ * @param resultnum Result number, for records with multiple matching results.
+ * Normally, you will only want to act on this when the result is 0.
*/
- virtual void OnLookupComplete(const std::string &result) = 0;
+ virtual void OnLookupComplete(const std::string &result, unsigned int ttl, bool cached, int resultnum = 0) = 0;
/**
* If an error occurs (such as NXDOMAIN, no domain name found) then this method
* will be called.
* this method will return -1.
*/
int GetId();
-};
-
-/**
- * Query and resource record types
- */
-enum QueryType
-{
- DNS_QUERY_A = 1, /* 'A' record: an IP address */
- DNS_QUERY_PTR = 12 /* 'PTR' record: a hostname */
+ /**
+ * 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:
+ /**
+ * Creator/Owner object
+ */
+ InspIRCd* ServerInstance;
+
/**
* The maximum value of a dns request id,
* 16 bits wide, 0xFFFF.
static const int MAX_REQUEST_ID = 0xFFFF;
/**
- * Requests that are currently 'in flight
+ * A counter used to form part of the pseudo-random id
*/
- requestlist requests;
+ int currid;
/**
- * Server address being used currently
+ * 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.
*/
- insp_inaddr myserver;
+ bool ip6munge;
/**
- * File descriptor being used to perform queries
+ * Currently cached items
+ */
+ dnscache* cache;
+
+ /** 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:
+
+ /**
+ * 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];
/**
- * 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.
+ */
+ 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);
- /**
- * Get the master socket fd, used internally
- */
- static int GetMasterSocket();
/**
- * Start the lookup of an ip from a hostname
+ * Start the lookup of an ipv4 from a hostname
*/
int GetIP(const char* name);
/**
- * Start the lookup of a hostname from an ip
+ * 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.
+ * @param resultnum Result number to fetch
*/
- DNSResult GetResult();
+ DNSResult GetResult(int resultnum);
/**
* 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,
* and clears the request lists.
*/
- DNS();
+ 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