1 #ifndef _GPXE_DNS_H 2 #define _GPXE_DNS_H 3 4 /** @file 5 * 6 * DNS protocol 7 * 8 */ 9 10 FILE_LICENCE ( GPL2_OR_LATER ); 11 12 #include <stdint.h> 13 #include <gpxe/in.h> 14 15 /* 16 * Constants 17 * 18 */ 19 20 #define DNS_TYPE_A 1 21 #define DNS_TYPE_CNAME 5 22 #define DNS_TYPE_ANY 255 23 24 #define DNS_CLASS_IN 1 25 #define DNS_CLASS_CS 2 26 #define DNS_CLASS_CH 3 27 #define DNS_CLASS_HS 4 28 29 #define DNS_FLAG_QUERY ( 0x00 << 15 ) 30 #define DNS_FLAG_RESPONSE ( 0x01 << 15 ) 31 #define DNS_FLAG_QR(flags) ( (flags) & ( 0x01 << 15 ) ) 32 #define DNS_FLAG_OPCODE_QUERY ( 0x00 << 11 ) 33 #define DNS_FLAG_OPCODE_IQUERY ( 0x01 << 11 ) 34 #define DNS_FLAG_OPCODE_STATUS ( 0x02 << 11 ) 35 #define DNS_FLAG_OPCODE(flags) ( (flags) & ( 0x0f << 11 ) ) 36 #define DNS_FLAG_RD ( 0x01 << 8 ) 37 #define DNS_FLAG_RA ( 0x01 << 7 ) 38 #define DNS_FLAG_RCODE_OK ( 0x00 << 0 ) 39 #define DNS_FLAG_RCODE_NX ( 0x03 << 0 ) 40 #define DNS_FLAG_RCODE(flags) ( (flags) & ( 0x0f << 0 ) ) 41 42 #define DNS_PORT 53 43 #define DNS_MAX_RETRIES 3 44 #define DNS_MAX_CNAME_RECURSION 0x30 45 46 /* 47 * DNS protocol structures 48 * 49 */ 50 struct dns_header { 51 uint16_t id; 52 uint16_t flags; 53 uint16_t qdcount; 54 uint16_t ancount; 55 uint16_t nscount; 56 uint16_t arcount; 57 } __attribute__ (( packed )); 58 59 struct dns_query_info { 60 uint16_t qtype; 61 uint16_t qclass; 62 } __attribute__ (( packed )); 63 64 struct dns_query { 65 struct dns_header dns; 66 char payload[ 256 + sizeof ( struct dns_query_info ) ]; 67 } __attribute__ (( packed )); 68 69 struct dns_rr_info_common { 70 uint16_t type; 71 uint16_t class; 72 uint32_t ttl; 73 uint16_t rdlength; 74 } __attribute__ (( packed )); 75 76 struct dns_rr_info_a { 77 struct dns_rr_info_common common; 78 struct in_addr in_addr; 79 } __attribute__ (( packed )); 80 81 struct dns_rr_info_cname { 82 struct dns_rr_info_common common; 83 char cname[0]; 84 } __attribute__ (( packed )); 85 86 union dns_rr_info { 87 struct dns_rr_info_common common; 88 struct dns_rr_info_a a; 89 struct dns_rr_info_cname cname; 90 }; 91 92 #endif /* _GPXE_DNS_H */ 93
