X-Git-Url: https://git.netwichtig.de/gitweb/?a=blobdiff_plain;f=include%2Fdns.h;h=adb9fdab853d02ab2f5eb5b5f1e1a23d95b3e780;hb=94fd751561acbf2ea0b830df8ed21eb3b6ccdc61;hp=7c128602f3a0ec5733c72e4e3528418d746a39a8;hpb=7da8ae070688fe8921edcd615d22d6cdd602459f;p=user%2Fhenk%2Fcode%2Finspircd.git diff --git a/include/dns.h b/include/dns.h index 7c128602f..adb9fdab8 100644 --- a/include/dns.h +++ b/include/dns.h @@ -2,14 +2,11 @@ * | Inspire Internet Relay Chat Daemon | * +------------------------------------+ * - * InspIRCd is copyright (C) 2002-2006 ChatSpike-Dev. - * E-mail: - * - * + * 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. * * --------------------------------------------------- */ @@ -37,19 +34,93 @@ Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA #include #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 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 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 > dnscache; +#else +typedef nspace::hash_map > dnscache; +#endif + /** * Error types that class Resolver can emit to its error method. */ @@ -59,7 +130,9 @@ enum ResolverError RESOLVER_NSDOWN = 1, RESOLVER_NXDOMAIN = 2, RESOLVER_NOTREADY = 3, - RESOLVER_BADIP = 4 + RESOLVER_BADIP = 4, + RESOLVER_TIMEOUT = 5, + RESLOVER_FORCEUNLOAD = 6 }; /** @@ -75,17 +148,38 @@ class DNSHeader; /** * 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 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. @@ -97,9 +191,17 @@ typedef requestlist::iterator requestlist_iter; * 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 */ @@ -107,7 +209,7 @@ class Resolver : public Extensible /** * 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. @@ -119,6 +221,16 @@ class Resolver : public Extensible * 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 @@ -128,16 +240,41 @@ class Resolver : public Extensible * 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. */ @@ -145,8 +282,14 @@ class Resolver : public Extensible /** * 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. @@ -163,15 +306,16 @@ class Resolver : public Extensible * 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 @@ -179,10 +323,15 @@ enum QueryType * 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. @@ -190,24 +339,43 @@ class DNS : public Extensible 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 @@ -215,49 +383,73 @@ class DNS : public Extensible 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 @@ -267,18 +459,64 @@ class DNS : public Extensible /** * 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