| Greg Hartman | 76d05dc | 2016-11-23 15:51:27 -0800 | [diff] [blame] | 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 */ |