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;
29 * Error types that class Resolver can emit to its error method.
35 RESOLVER_NXDOMAIN = 2,
40 /** DNS is a singleton class used by the core to dispatch dns
41 * requests to the dns server, and route incoming dns replies
42 * back to Resolver objects, based upon the request ID. You
43 * should never use this class yourself.
45 class DNS : public Extensible
48 int dns_getip4(const char* name);
49 int dns_getname4(const insp_inaddr* ip);
50 DNSResult dns_getresult();
56 * The Resolver class is a high-level abstraction for resolving DNS entries.
57 * It can do forward and reverse IPv4 lookups, and when IPv6 is supported, will
58 * also be able to do those, transparent of protocols. Module developers must
59 * extend this class via inheritence, and then insert a pointer to their derived
60 * class into the core using Server::AddResolver(). Once you have done this,
61 * the class will be able to receive callbacks. There are two callbacks which
62 * can occur by calling virtual methods, one is a success situation, and the other
65 class Resolver : public Extensible
69 * The input data, either a host or an IP address
73 * True if a forward lookup is being performed, false if otherwise
77 * The DNS erver being used for lookups. If this is an empty string,
78 * the value of ServerConfig::DNSServer is used instead.
82 * The ID allocated to your lookup. This is a pseud-random number
83 * between 0 and 65535, a value of -1 indicating a failure.
84 * The core uses this to route results to the correct objects.
89 * Initiate DNS lookup. Your class should not attempt to delete or free these
90 * objects, as the core will do this for you. They must always be created upon
91 * the heap using new, as you cannot be sure at what time they will be deleted.
92 * Allocating them on the stack or attempting to delete them yourself could cause
93 * the object to go 'out of scope' and cause a segfault in the core if the result
94 * arrives at a later time.
95 * @param source The IP or hostname to resolve
96 * @param forward Set to true to perform a forward lookup (hostname to ip) or false
97 * to perform a reverse lookup (ip to hostname). Lookups on A records and PTR
98 * records are supported. CNAME and MX are not supported by this resolver.
99 * If InspIRCd is compiled with ipv6 support, lookups on AAAA records are preferred
100 * and supported over A records.
101 * @throw ModuleException This class may throw an instance of ModuleException, in the
102 * event a lookup could not be allocated, or a similar hard error occurs such as
103 * the network being down.
105 Resolver(const std::string &source, bool forward);
107 * The default destructor does nothing.
111 * When your lookup completes, this method will be called.
112 * @param result The resulting DNS lookup, either an IP address or a hostname.
114 virtual void OnLookupComplete(const std::string &result);
116 * If an error occurs (such as NXDOMAIN, no domain name found) then this method
118 * @param e A ResolverError enum containing the error type which has occured.
120 virtual void OnError(ResolverError e);
122 * This method is called by the core when the object's file descriptor is ready
123 * for reading, and will then dispatch a call to either OnLookupComplete or
124 * OnError. You should never call this method yourself.
126 bool ProcessResult(const std::string &result);
128 * Returns the file descriptor of this class. This is primarily used by the core
129 * to determine where in various tables to place a pointer to your class, but it
130 * is safe to call and use this method.
136 * Clear the pointer table used for Resolver classes,
137 * translate ServerConfig::DNSServer into an insp_inaddr,
138 * establish binding on UDP socket for DNS requests.
142 * Deal with a Resolver class which has become readable
144 void dns_deal_with_classes(int fd);
146 * Add a resolver class to our active table
148 bool dns_add_class(Resolver* r);