diff options
Diffstat (limited to 'src/include/dns.h')
-rw-r--r-- | src/include/dns.h | 81 |
1 files changed, 81 insertions, 0 deletions
diff --git a/src/include/dns.h b/src/include/dns.h new file mode 100644 index 00000000..cd26a961 --- /dev/null +++ b/src/include/dns.h @@ -0,0 +1,81 @@ +#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 */ |