#include "base.h"
#include "socketengine.h"
#include "socket.h"
+#include "hash_map.h"
+#include "hashcomp.h"
using namespace std;
using irc::sockets::insp_aton;
/**
* 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.
*/
/**
* A DNS Resource Record (rr)
*/
-class ResourceRecord;
+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 */
+ 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;
-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
-
+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.
* 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:
/**
* 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
* 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
* 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, Module* creator = NULL);
+ 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();
-
/**
* 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 EventHandler
+class CoreExport DNS : public EventHandler
{
private:
+ /**
+ * Creator/Owner object
+ */
InspIRCd* ServerInstance;
/**
*/
static const int MAX_REQUEST_ID = 0xFFFF;
- /**
- * Server address being used currently
- */
- insp_inaddr myserver;
-
/**
* A counter used to form part of the pseudo-random id
*/
*/
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.
* 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
*/
/**
* 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
/**
* 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,
* 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