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#ifndef DNS_H
#define DNS_H
/** Valid query types
*/
enum QueryType
{
/* Nothing */
DNS_QUERY_NONE,
/* A simple A lookup */
DNS_QUERY_A = 1,
/* A CNAME lookup */
DNS_QUERY_CNAME = 5,
/* Reverse DNS lookup */
DNS_QUERY_PTR = 12,
/* IPv6 AAAA lookup */
DNS_QUERY_AAAA = 28
};
/** Flags that can be AND'd into DNSPacket::flags to receive certain values
*/
enum QueryFlags
{
DNS_QUERYFLAGS_QR = 0x8000,
DNS_QUERYFLAGS_OPCODE = 0x7800,
DNS_QUERYFLAGS_AA = 0x400,
DBS_QUERYFLAGS_TC = 0x200,
DNS_QUERYFLAGS_RD = 0x100,
DNS_QUERYFLAGS_RA = 0x80,
DNS_QUERYFLAGS_Z = 0x70,
DNS_QUERYFLAGS_RCODE = 0xF
};
enum DNSError
{
DNS_ERROR_NONE,
DNS_ERROR_UNKNOWN,
DNS_ERROR_UNLOADED,
DNS_ERROR_TIMEOUT,
DNS_ERROR_NOT_AN_ANSWER,
DNS_ERROR_NONSTANDARD_QUERY,
DNS_ERROR_FORMAT_ERROR,
DNS_ERROR_SERVER_FAILURE,
DNS_ERROR_DOMAIN_NOT_FOUND,
DNS_ERROR_NOT_IMPLEMENTED,
DNS_ERROR_REFUSED,
DNS_ERROR_NO_RECORDS,
DNS_ERROR_INVALIDTYPE
};
class DNSRequestTimeout; // Forward declarations
struct DNSRecord;
class Module;
/** The request
*/
class CoreExport DNSRequest
{
/* Timeout timer for this request */
DNSRequestTimeout *timeout;
/* Use result cache if available */
bool use_cache;
public:
/* Request id */
unsigned short id;
/* Creator of this request */
Module *creator;
/* Address we're looking up */
Anope::string address;
/* QueryType, A, AAAA, PTR etc */
QueryType QT;
DNSRequest(const Anope::string &addr, QueryType qt, bool cache = false, Module *c = NULL);
virtual ~DNSRequest();
void Process();
virtual void OnLookupComplete(const DNSRecord *r) = 0;
virtual void OnError(const DNSRecord *r);
};
/** A full packet sent to the nameserver, may contain multiple queries
*/
struct DNSPacket
{
/* Our 16-bit id for this header */
unsigned short id;
/* Flags on the query */
unsigned short flags;
/* Number of queries */
unsigned short qdcount;
/* Number of resource records in answer */
unsigned short ancount;
/* Number of NS resource records in authority records section */
unsigned short nscount;
/* Number of resource records in the additional records section */
unsigned short arcount;
/* How many of the bytes of the payload are in use */
unsigned short payload_count;
/* The queries, at most can be 512 bytes */
unsigned char payload[512];
inline DNSPacket();
bool AddQuestion(const Anope::string &address, QueryType qt);
inline void FillPacket(const unsigned char *input, const size_t length);
inline void FillBuffer(unsigned char *buffer);
};
struct DNSRecord
{
/* Name of the initial lookup */
Anope::string name;
/* Result of the lookup */
Anope::string result;
/* Type of query this was */
QueryType type;
/* Error, if there was one */
DNSError error;
/* Record class, should always be 1 */
unsigned short record_class;
/* Time to live */
time_t ttl;
/* Record length */
unsigned short rdlength;
inline DNSRecord(const Anope::string &n);
/* When this record was created in our cache */
time_t created;
};
/** The socket used to talk to the nameserver, uses UDP
*/
class DNSSocket : public ConnectionSocket
{
private:
int SendTo(const unsigned char *buf, size_t len) const;
int RecvFrom(char *buf, size_t size, sockaddrs &addrs) const;
public:
DNSSocket();
virtual ~DNSSocket();
bool ProcessRead();
bool ProcessWrite();
};
/** DNS manager, manages the connection and all requests
*/
class DNSManager : public Timer
{
std::multimap<Anope::string, DNSRecord *> cache;
public:
DNSSocket *sock;
std::deque<DNSPacket *> packets;
std::map<short, DNSRequest *> requests;
static const int DNSPort = 53;
DNSManager();
~DNSManager();
void AddCache(DNSRecord *rr);
bool CheckCache(DNSRequest *request);
void Tick(time_t now);
void Cleanup(Module *mod);
/** Does a BLOCKING DNS query and returns the first IP.
* Only use this if you know what you are doing. Unless you specifically
* need a blocking query use the DNSRequest system
*/
static DNSRecord BlockingQuery(const Anope::string &mask, QueryType qt);
};
/** A DNS timeout, one is made for every DNS request to detect timeouts
*/
class DNSRequestTimeout : public Timer
{
DNSRequest *request;
public:
bool done;
DNSRequestTimeout(DNSRequest *r, time_t timeout);
~DNSRequestTimeout();
void Tick(time_t);
};
extern DNSManager *DNSEngine;
#endif // DNS_H
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