106 lines
2.7 KiB
C
106 lines
2.7 KiB
C
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#ifndef HV_DNS_H_
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#define HV_DNS_H_
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#include "hexport.h"
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#include "hplatform.h"
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#define DNS_PORT 53
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#define DNS_QUERY 0
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#define DNS_RESPONSE 1
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#define DNS_TYPE_A 1 // ipv4
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#define DNS_TYPE_NS 2
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#define DNS_TYPE_CNAME 5
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#define DNS_TYPE_SOA 6
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#define DNS_TYPE_WKS 11
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#define DNS_TYPE_PTR 12
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#define DNS_TYPE_HINFO 13
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#define DNS_TYPE_MX 15
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#define DNS_TYPE_AAAA 28 // ipv6
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#define DNS_TYPE_AXFR 252
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#define DNS_TYPE_ANY 255
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#define DNS_CLASS_IN 1
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#define DNS_NAME_MAXLEN 256
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// sizeof(dnshdr_t) = 12
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typedef struct dnshdr_s {
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uint16_t transaction_id;
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// flags
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#if BYTE_ORDER == LITTLE_ENDIAN
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uint8_t rd:1;
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uint8_t tc:1;
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uint8_t aa:1;
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uint8_t opcode:4;
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uint8_t qr:1;
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uint8_t rcode:4;
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uint8_t cd:1;
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uint8_t ad:1;
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uint8_t res:1;
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uint8_t ra:1;
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#elif BYTE_ORDER == BIG_ENDIAN
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uint8_t qr:1; // DNS_QUERY or DNS_RESPONSE
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uint8_t opcode:4;
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uint8_t aa:1; // authoritative
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uint8_t tc:1; // truncated
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uint8_t rd:1; // recursion desired
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uint8_t ra:1; // recursion available
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uint8_t res:1; // reserved
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uint8_t ad:1; // authenticated data
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uint8_t cd:1; // checking disable
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uint8_t rcode:4;
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#else
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#error "BYTE_ORDER undefined!"
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#endif
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uint16_t nquestion;
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uint16_t nanswer;
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uint16_t nauthority;
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uint16_t naddtional;
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} dnshdr_t;
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typedef struct dns_rr_s {
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char name[DNS_NAME_MAXLEN]; // original domain, such as www.example.com
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uint16_t rtype;
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uint16_t rclass;
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uint32_t ttl;
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uint16_t datalen;
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char* data;
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} dns_rr_t;
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typedef struct dns_s {
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dnshdr_t hdr;
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dns_rr_t* questions;
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dns_rr_t* answers;
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dns_rr_t* authorities;
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dns_rr_t* addtionals;
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} dns_t;
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BEGIN_EXTERN_C
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// www.example.com => 3www7example3com
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HV_EXPORT int dns_name_encode(const char* domain, char* buf);
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// 3www7example3com => www.example.com
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HV_EXPORT int dns_name_decode(const char* buf, char* domain);
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HV_EXPORT int dns_rr_pack(dns_rr_t* rr, char* buf, int len);
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HV_EXPORT int dns_rr_unpack(char* buf, int len, dns_rr_t* rr, int is_question);
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HV_EXPORT int dns_pack(dns_t* dns, char* buf, int len);
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HV_EXPORT int dns_unpack(char* buf, int len, dns_t* dns);
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// NOTE: free dns->rrs
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HV_EXPORT void dns_free(dns_t* dns);
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// dns_pack -> sendto -> recvfrom -> dns_unpack
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HV_EXPORT int dns_query(dns_t* query, dns_t* response, const char* nameserver DEFAULT("127.0.1.1"));
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// domain -> dns_t query; -> dns_query -> dns_t response; -> addrs
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HV_EXPORT int nslookup(const char* domain, uint32_t* addrs, int naddr, const char* nameserver DEFAULT("127.0.1.1"));
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END_EXTERN_C
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#endif // HV_DNS_H_
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