/*
* pkthdr.h - packet header from wire conversion routines
*
* a Net::DNS like library for C
*
* (c) NLnet Labs, 2005-2006
*
* See the file LICENSE for the license
*/

/**
* \file
*
* Contains functions that translate dns data from the wire format (as sent
* by servers and clients) to the internal structures for the packet header.
*/

#ifndef LDNS_PKTHDR_H
#define LDNS_PKTHDR_H

#ifdef __cplusplus
extern "C" {
#endif

/* The length of the header */
#define LDNS_HEADER_SIZE        12

/* First octet of flags */
#define LDNS_RD_MASK            0x01U
#define LDNS_RD_SHIFT   0
#define LDNS_RD_WIRE(wirebuf)   (*(wirebuf+2) & LDNS_RD_MASK)
#define LDNS_RD_SET(wirebuf)    (*(wirebuf+2) |= LDNS_RD_MASK)
#define LDNS_RD_CLR(wirebuf)    (*(wirebuf+2) &= ~LDNS_RD_MASK)

#define LDNS_TC_MASK            0x02U
#define LDNS_TC_SHIFT   1
#define LDNS_TC_WIRE(wirebuf)   (*(wirebuf+2) & LDNS_TC_MASK)
#define LDNS_TC_SET(wirebuf)    (*(wirebuf+2) |= LDNS_TC_MASK)
#define LDNS_TC_CLR(wirebuf)    (*(wirebuf+2) &= ~LDNS_TC_MASK)

#define LDNS_AA_MASK            0x04U
#define LDNS_AA_SHIFT   2
#define LDNS_AA_WIRE(wirebuf)   (*(wirebuf+2) & LDNS_AA_MASK)
#define LDNS_AA_SET(wirebuf)    (*(wirebuf+2) |= LDNS_AA_MASK)
#define LDNS_AA_CLR(wirebuf)    (*(wirebuf+2) &= ~LDNS_AA_MASK)

#define LDNS_OPCODE_MASK        0x78U
#define LDNS_OPCODE_SHIFT       3
#define LDNS_OPCODE_WIRE(wirebuf)       ((*(wirebuf+2) & LDNS_OPCODE_MASK) >> LDNS_OPCODE_SHIFT)
#define LDNS_OPCODE_SET(wirebuf, opcode) \
       (*(wirebuf+2) = ((*(wirebuf+2)) & ~LDNS_OPCODE_MASK) | ((opcode) << LDNS_OPCODE_SHIFT))

#define LDNS_QR_MASK            0x80U
#define LDNS_QR_SHIFT   7
#define LDNS_QR_WIRE(wirebuf)   (*(wirebuf+2) & LDNS_QR_MASK)
#define LDNS_QR_SET(wirebuf)    (*(wirebuf+2) |= LDNS_QR_MASK)
#define LDNS_QR_CLR(wirebuf)    (*(wirebuf+2) &= ~LDNS_QR_MASK)

/* Second octet of flags */
#define LDNS_RCODE_MASK 0x0fU
#define LDNS_RCODE_SHIFT        0
#define LDNS_RCODE_WIRE(wirebuf)        (*(wirebuf+3) & LDNS_RCODE_MASK)
#define LDNS_RCODE_SET(wirebuf, rcode) \
       (*(wirebuf+3) = ((*(wirebuf+3)) & ~LDNS_RCODE_MASK) | (rcode))

#define LDNS_CD_MASK            0x10U
#define LDNS_CD_SHIFT   4
#define LDNS_CD_WIRE(wirebuf)   (*(wirebuf+3) & LDNS_CD_MASK)
#define LDNS_CD_SET(wirebuf)    (*(wirebuf+3) |= LDNS_CD_MASK)
#define LDNS_CD_CLR(wirebuf)    (*(wirebuf+3) &= ~LDNS_CD_MASK)

#define LDNS_AD_MASK            0x20U
#define LDNS_AD_SHIFT   5
#define LDNS_AD_WIRE(wirebuf)   (*(wirebuf+3) & LDNS_AD_MASK)
#define LDNS_AD_SET(wirebuf)    (*(wirebuf+3) |= LDNS_AD_MASK)
#define LDNS_AD_CLR(wirebuf)    (*(wirebuf+3) &= ~LDNS_AD_MASK)

#define LDNS_Z_MASK             0x40U
#define LDNS_Z_SHIFT            6
#define LDNS_Z_WIRE(wirebuf)    (*(wirebuf+3) & LDNS_Z_MASK)
#define LDNS_Z_SET(wirebuf)     (*(wirebuf+3) |= LDNS_Z_MASK)
#define LDNS_Z_CLR(wirebuf)     (*(wirebuf+3) &= ~LDNS_Z_MASK)

#define LDNS_RA_MASK            0x80U
#define LDNS_RA_SHIFT   7
#define LDNS_RA_WIRE(wirebuf)   (*(wirebuf+3) & LDNS_RA_MASK)
#define LDNS_RA_SET(wirebuf)    (*(wirebuf+3) |= LDNS_RA_MASK)
#define LDNS_RA_CLR(wirebuf)    (*(wirebuf+3) &= ~LDNS_RA_MASK)

/* Query ID */
#define LDNS_ID_WIRE(wirebuf)           (sldns_read_uint16(wirebuf))
#define LDNS_ID_SET(wirebuf, id)        (sldns_write_uint16(wirebuf, id))

/* Counter of the question section */
#define LDNS_QDCOUNT_OFF                4
/*
#define QDCOUNT(wirebuf)                (ntohs(*(uint16_t *)(wirebuf+QDCOUNT_OFF)))
*/
#define LDNS_QDCOUNT(wirebuf)           (sldns_read_uint16(wirebuf+LDNS_QDCOUNT_OFF))
#define LDNS_QDCOUNT_SET(wirebuf, i)    (sldns_write_uint16(wirebuf+LDNS_QDCOUNT_OFF, i))

/* Counter of the answer section */
#define LDNS_ANCOUNT_OFF                6
#define LDNS_ANCOUNT(wirebuf)           (sldns_read_uint16(wirebuf+LDNS_ANCOUNT_OFF))
#define LDNS_ANCOUNT_SET(wirebuf, i)    (sldns_write_uint16(wirebuf+LDNS_ANCOUNT_OFF, i))

/* Counter of the authority section */
#define LDNS_NSCOUNT_OFF                8
#define LDNS_NSCOUNT(wirebuf)           (sldns_read_uint16(wirebuf+LDNS_NSCOUNT_OFF))
#define LDNS_NSCOUNT_SET(wirebuf, i)    (sldns_write_uint16(wirebuf+LDNS_NSCOUNT_OFF, i))

/* Counter of the additional section */
#define LDNS_ARCOUNT_OFF                10
#define LDNS_ARCOUNT(wirebuf)           (sldns_read_uint16(wirebuf+LDNS_ARCOUNT_OFF))
#define LDNS_ARCOUNT_SET(wirebuf, i)    (sldns_write_uint16(wirebuf+LDNS_ARCOUNT_OFF, i))

/**
* The sections of a packet
*/
enum sldns_enum_pkt_section {
       LDNS_SECTION_QUESTION = 0,
       LDNS_SECTION_ANSWER = 1,
       LDNS_SECTION_AUTHORITY = 2,
       LDNS_SECTION_ADDITIONAL = 3,
       /** bogus section, if not interested */
       LDNS_SECTION_ANY = 4,
       /** used to get all non-question rrs from a packet */
       LDNS_SECTION_ANY_NOQUESTION = 5
};
typedef enum sldns_enum_pkt_section sldns_pkt_section;

/* opcodes for pkt's */
enum sldns_enum_pkt_opcode {
       LDNS_PACKET_QUERY = 0,
       LDNS_PACKET_IQUERY = 1,
       LDNS_PACKET_STATUS = 2, /* there is no 3?? DNS is weird */
       LDNS_PACKET_NOTIFY = 4,
       LDNS_PACKET_UPDATE = 5
};
typedef enum sldns_enum_pkt_opcode sldns_pkt_opcode;

/* rcodes for pkts */
enum sldns_enum_pkt_rcode {
       LDNS_RCODE_NOERROR = 0,
       LDNS_RCODE_FORMERR = 1,
       LDNS_RCODE_SERVFAIL = 2,
       LDNS_RCODE_NXDOMAIN = 3,
       LDNS_RCODE_NOTIMPL = 4,
       LDNS_RCODE_REFUSED = 5,
       LDNS_RCODE_YXDOMAIN = 6,
       LDNS_RCODE_YXRRSET = 7,
       LDNS_RCODE_NXRRSET = 8,
       LDNS_RCODE_NOTAUTH = 9,
       LDNS_RCODE_NOTZONE = 10
};
typedef enum sldns_enum_pkt_rcode sldns_pkt_rcode;

#ifdef __cplusplus
}
#endif

#endif /* LDNS_PKTHDR_H */