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- #ifndef _IPXE_DNS_H
- #define _IPXE_DNS_H
-
- /** @file
- *
- * DNS protocol
- *
- */
-
- FILE_LICENCE ( GPL2_OR_LATER );
-
- #include <stdint.h>
- #include <ipxe/in.h>
-
- /** DNS server port */
- #define DNS_PORT 53
-
- /** An RFC1035-encoded DNS name */
- struct dns_name {
- /** Start of data */
- void *data;
- /** Offset of name within data */
- size_t offset;
- /** Total length of data */
- size_t len;
- };
-
- /**
- * Test for a DNS compression pointer
- *
- * @v byte Initial byte
- * @ret is_compressed Is a compression pointer
- */
- #define DNS_IS_COMPRESSED( byte ) ( (byte) & 0xc0 )
-
- /**
- * Extract DNS compression pointer
- *
- * @v word Initial word
- * @ret offset Offset
- */
- #define DNS_COMPRESSED_OFFSET( word ) ( (word) & ~0xc000 )
-
- /**
- * Extract DNS label length
- *
- * @v byte Initial byte
- * @ret len Label length
- */
- #define DNS_LABEL_LEN( byte ) ( (byte) & ~0xc0 )
-
- /** Maximum length of a single DNS label */
- #define DNS_MAX_LABEL_LEN 0x3f
-
- /** Maximum length of a DNS name (mandated by RFC1035 section 2.3.4) */
- #define DNS_MAX_NAME_LEN 255
-
- /** Maximum depth of CNAME recursion
- *
- * This is a policy decision.
- */
- #define DNS_MAX_CNAME_RECURSION 32
-
- /** A DNS packet header */
- struct dns_header {
- /** Query identifier */
- uint16_t id;
- /** Flags */
- uint16_t flags;
- /** Number of question records */
- uint16_t qdcount;
- /** Number of answer records */
- uint16_t ancount;
- /** Number of name server records */
- uint16_t nscount;
- /** Number of additional records */
- uint16_t arcount;
- } __attribute__ (( packed ));
-
- /** Recursion desired flag */
- #define DNS_FLAG_RD 0x0100
-
- /** A DNS question */
- struct dns_question {
- /** Query type */
- uint16_t qtype;
- /** Query class */
- uint16_t qclass;
- } __attribute__ (( packed ));
-
- /** DNS class "IN" */
- #define DNS_CLASS_IN 1
-
- /** A DNS resource record */
- struct dns_rr_common {
- /** Type */
- uint16_t type;
- /** Class */
- uint16_t class;
- /** Time to live */
- uint32_t ttl;
- /** Resource data length */
- uint16_t rdlength;
- } __attribute__ (( packed ));
-
- /** Type of a DNS "A" record */
- #define DNS_TYPE_A 1
-
- /** A DNS "A" record */
- struct dns_rr_a {
- /** Common fields */
- struct dns_rr_common common;
- /** IPv4 address */
- struct in_addr in_addr;
- } __attribute__ (( packed ));
-
- /** Type of a DNS "AAAA" record */
- #define DNS_TYPE_AAAA 28
-
- /** A DNS "AAAA" record */
- struct dns_rr_aaaa {
- /** Common fields */
- struct dns_rr_common common;
- /** IPv6 address */
- struct in6_addr in6_addr;
- } __attribute__ (( packed ));
-
- /** Type of a DNS "NAME" record */
- #define DNS_TYPE_CNAME 5
-
- /** A DNS "CNAME" record */
- struct dns_rr_cname {
- /** Common fields */
- struct dns_rr_common common;
- } __attribute__ (( packed ));
-
- /** A DNS resource record */
- union dns_rr {
- /** Common fields */
- struct dns_rr_common common;
- /** "A" record */
- struct dns_rr_a a;
- /** "AAAA" record */
- struct dns_rr_aaaa aaaa;
- /** "CNAME" record */
- struct dns_rr_cname cname;
- };
-
- extern int dns_encode ( const char *string, struct dns_name *name );
- extern int dns_decode ( struct dns_name *name, char *data, size_t len );
- extern int dns_compare ( struct dns_name *first, struct dns_name *second );
- extern int dns_copy ( struct dns_name *src, struct dns_name *dst );
- extern int dns_skip ( struct dns_name *name );
-
- #endif /* _IPXE_DNS_H */
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