A working DNS resolver (not yet tied in to anything)

1 files changed, 109 insertions, 0 deletions

diff --git a/src/include/gpxe/dns.h b/src/include/gpxe/dns.h
new file mode 100644
index 000000000..49292d588
--- /dev/null
+++ b/src/include/gpxe/dns.h
@@ -0,0 +1,109 @@
+#ifndef _GPXE_DNS_H
+#define _GPXE_DNS_H
+
+/** @file
+ *
+ * DNS protocol
+ *
+ */
+
+#include <stdint.h>
+#include <gpxe/in.h>
+#include <gpxe/async.h>
+#include <gpxe/retry.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_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 dns_header dns;
+	char		payload[ 256 + sizeof ( struct dns_query_info ) ];
+} __attribute__ (( packed ));
+
+struct dns_rr_info_common {
+	uint16_t	type;
+	uint16_t	class;
+	uint32_t	ttl;
+	uint16_t	rdlength;
+} __attribute__ (( packed ));
+
+struct dns_rr_info_a {
+	struct dns_rr_info_common common;
+	struct in_addr in_addr;
+} __attribute__ (( packed ));
+
+struct dns_rr_info_cname {
+	struct dns_rr_info_common common;
+	char cname[0];
+} __attribute__ (( packed ));
+
+union dns_rr_info {
+	struct dns_rr_info_common common;
+	struct dns_rr_info_a a;
+	struct dns_rr_info_cname cname;
+};
+
+struct dns_request {
+
+	struct sockaddr_tcpip *st;
+
+	struct async async;
+	struct dns_query query;
+	struct dns_query_info *qinfo;
+
+	unsigned int recursion;
+
+	struct udp_connection udp;
+	struct retry_timer timer;
+};
+
+extern int dns_resolv ( const char *name, struct sockaddr_tcpip *st,
+			struct async *parent );
+
+#endif /* _GPXE_DNS_H */