2 dns.h - dns library declarations based on firedns Copyright (C) 2002 Ian Gulliver
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22 #include "inspircd_config.h"
26 typedef std::pair<int,std::string> DNSResult;
27 typedef std::pair<unsigned char*, std::string> DNSInfo;
30 * Error types that class Resolver can emit to its error method.
36 RESOLVER_NXDOMAIN = 2,
37 RESOLVER_NOTREADY = 3,
45 * The Resolver class is a high-level abstraction for resolving DNS entries.
46 * It can do forward and reverse IPv4 lookups, and where IPv6 is supported, will
47 * also be able to do those, transparent of protocols. Module developers must
48 * extend this class via inheritence, and then insert a pointer to their derived
49 * class into the core using Server::AddResolver(). Once you have done this,
50 * the class will be able to receive callbacks. There are two callbacks which
51 * can occur by calling virtual methods, one is a success situation, and the other
54 class Resolver : public Extensible
58 * The input data, either a host or an IP address
62 * True if a forward lookup is being performed, false if otherwise
66 * The DNS erver being used for lookups. If this is an empty string,
67 * the value of ServerConfig::DNSServer is used instead.
71 * The ID allocated to your lookup. This is a pseud-random number
72 * between 0 and 65535, a value of -1 indicating a failure.
73 * The core uses this to route results to the correct objects.
78 * Initiate DNS lookup. Your class should not attempt to delete or free these
79 * objects, as the core will do this for you. They must always be created upon
80 * the heap using new, as you cannot be sure at what time they will be deleted.
81 * Allocating them on the stack or attempting to delete them yourself could cause
82 * the object to go 'out of scope' and cause a segfault in the core if the result
83 * arrives at a later time.
84 * @param source The IP or hostname to resolve
85 * @param forward Set to true to perform a forward lookup (hostname to ip) or false
86 * to perform a reverse lookup (ip to hostname). Lookups on A records and PTR
87 * records are supported. CNAME and MX are not supported by this resolver.
88 * If InspIRCd is compiled with ipv6 support, lookups on AAAA records are preferred
89 * and supported over A records.
90 * @throw ModuleException This class may throw an instance of ModuleException, in the
91 * event a lookup could not be allocated, or a similar hard error occurs such as
92 * the network being down.
94 Resolver(const std::string &source, bool forward);
96 * The default destructor does nothing.
100 * When your lookup completes, this method will be called.
101 * @param result The resulting DNS lookup, either an IP address or a hostname.
103 virtual void OnLookupComplete(const std::string &result) = 0;
105 * If an error occurs (such as NXDOMAIN, no domain name found) then this method
107 * @param e A ResolverError enum containing the error type which has occured.
108 * @param errormessage The error text of the error that occured.
110 virtual void OnError(ResolverError e, const std::string &errormessage);
112 * Returns the id value of this class. This is primarily used by the core
113 * to determine where in various tables to place a pointer to your class, but it
114 * is safe to call and use this method.
115 * As specified in RFC1035, each dns request has a 16 bit ID value, ranging
116 * from 0 to 65535. If there is an issue and the core cannot send your request,
117 * this method will return -1.
122 /** DNS is a singleton class used by the core to dispatch dns
123 * requests to the dns server, and route incoming dns replies
124 * back to Resolver objects, based upon the request ID. You
125 * should never use this class yourself.
127 class DNS : public Extensible
130 insp_inaddr myserver;
131 static int MasterSocket;
133 static int GetMasterSocket();
134 int GetIP(const char* name);
135 int GetName(const insp_inaddr* ip);
136 DNSResult GetResult();
137 void MarshallReads(int fd);
138 bool AddResolverClass(Resolver* r);
139 DNSRequest* DNSAddQuery(DNSHeader *header, int &id);