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#ifndef DNS_RESOLVER_H
#define DNS_RESOLVER_H
#include "stdint.h"
#include "nic.h"
#include "in.h"
/*
* Constants
*
*/
#define DNS_TYPE_A 1
#define DNS_TYPE_CNAME 5
#define DNS_TYPE_ANY 255
#define DNS_CLASS_IN 1
#define DNS_CLASS_CS 2
#define DNS_CLASS_CH 3
#define DNS_CLASS_HS 4
#define DNS_FLAG_QUERY ( 0x00 << 15 )
#define DNS_FLAG_RESPONSE ( 0x01 << 15 )
#define DNS_FLAG_QR(flags) ( (flags) & ( 0x01 << 15 ) )
#define DNS_FLAG_OPCODE_QUERY ( 0x00 << 11 )
#define DNS_FLAG_OPCODE_IQUERY ( 0x01 << 11 )
#define DNS_FLAG_OPCODE_STATUS ( 0x02 << 11 )
#define DNS_FLAG_OPCODE(flags) ( (flags) & ( 0x0f << 11 ) )
#define DNS_FLAG_RD ( 0x01 << 8 )
#define DNS_FLAG_RA ( 0x01 << 7 )
#define DNS_FLAG_RCODE_OK ( 0x00 << 0 )
#define DNS_FLAG_RCODE_NX ( 0x03 << 0 )
#define DNS_FLAG_RCODE(flags) ( (flags) & ( 0x0f << 0 ) )
#define DNS_UDP_PORT 53
#define DNS_MAX_RETRIES 3
#define DNS_MAX_CNAME_RECURSION 0x30
/*
* DNS protocol structures
*
*/
struct dns_header {
uint16_t id;
uint16_t flags;
uint16_t qdcount;
uint16_t ancount;
uint16_t nscount;
uint16_t arcount;
} __attribute__ (( packed ));
struct dns_query_info {
uint16_t qtype;
uint16_t qclass;
} __attribute__ (( packed ));
struct dns_query {
struct iphdr ip;
struct udphdr udp;
struct dns_header dns;
char payload[ 256 + sizeof ( struct dns_query_info ) ];
} __attribute__ (( packed ));
struct dns_rr_info {
uint16_t type;
uint16_t class;
uint16_t ttl;
uint16_t rdlength;
} __attribute__ (( packed ));
struct dns_rr_info_a {
struct dns_rr_info;
struct in_addr in_addr;
} __attribute__ (( packed ));
struct dns_rr_info_cname {
struct dns_rr_info;
char cname[0];
};
#endif /* DNS_RESOLVER_H */
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