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,
42 /** DNS is a singleton class used by the core to dispatch dns
43 * requests to the dns server, and route incoming dns replies
44 * back to Resolver objects, based upon the request ID. You
45 * should never use this class yourself.
47 class DNS : public Extensible
50 int dns_getip(const char* name);
51 int dns_getname(const insp_inaddr* ip);
52 DNSResult dns_getresult();
58 * The Resolver class is a high-level abstraction for resolving DNS entries.
59 * It can do forward and reverse IPv4 lookups, and where IPv6 is supported, will
60 * also be able to do those, transparent of protocols. Module developers must
61 * extend this class via inheritence, and then insert a pointer to their derived
62 * class into the core using Server::AddResolver(). Once you have done this,
63 * the class will be able to receive callbacks. There are two callbacks which
64 * can occur by calling virtual methods, one is a success situation, and the other
67 class Resolver : public Extensible
71 * The input data, either a host or an IP address
75 * True if a forward lookup is being performed, false if otherwise
79 * The DNS erver being used for lookups. If this is an empty string,
80 * the value of ServerConfig::DNSServer is used instead.
84 * The ID allocated to your lookup. This is a pseud-random number
85 * between 0 and 65535, a value of -1 indicating a failure.
86 * The core uses this to route results to the correct objects.
91 * Initiate DNS lookup. Your class should not attempt to delete or free these
92 * objects, as the core will do this for you. They must always be created upon
93 * the heap using new, as you cannot be sure at what time they will be deleted.
94 * Allocating them on the stack or attempting to delete them yourself could cause
95 * the object to go 'out of scope' and cause a segfault in the core if the result
96 * arrives at a later time.
97 * @param source The IP or hostname to resolve
98 * @param forward Set to true to perform a forward lookup (hostname to ip) or false
99 * to perform a reverse lookup (ip to hostname). Lookups on A records and PTR
100 * records are supported. CNAME and MX are not supported by this resolver.
101 * If InspIRCd is compiled with ipv6 support, lookups on AAAA records are preferred
102 * and supported over A records.
103 * @throw ModuleException This class may throw an instance of ModuleException, in the
104 * event a lookup could not be allocated, or a similar hard error occurs such as
105 * the network being down.
107 Resolver(const std::string &source, bool forward);
109 * The default destructor does nothing.
113 * When your lookup completes, this method will be called.
114 * @param result The resulting DNS lookup, either an IP address or a hostname.
116 virtual void OnLookupComplete(const std::string &result) = 0;
118 * If an error occurs (such as NXDOMAIN, no domain name found) then this method
120 * @param e A ResolverError enum containing the error type which has occured.
121 * @param errormessage The error text of the error that occured.
123 virtual void OnError(ResolverError e, const std::string &errormessage);
125 * Returns the id value of this class. This is primarily used by the core
126 * to determine where in various tables to place a pointer to your class, but it
127 * is safe to call and use this method.
128 * As specified in RFC1035, each dns request has a 16 bit ID value, ranging
129 * from 0 to 65535. If there is an issue and the core cannot send your request,
130 * this method will return -1.
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);