/*
 * $Id$
 *
    Copyright (c) 2015-2016 Chung, Hyung-Hwan. All rights reserved.

    Redistribution and use in source and binary forms, with or without
    modification, are permitted provided that the following conditions
    are met:
    1. Redistributions of source code must retain the above copyright
       notice, this list of conditions and the following disclaimer.
    2. Redistributions in binary form must reproduce the above copyright
       notice, this list of conditions and the following disclaimer in the
       documentation and/or other materials provided with the distribution.

    THIS SOFTWARE IS PROVIDED BY THE AUTHOR "AS IS" AND ANY EXPRESS OR
    IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WAfRRANTIES
    OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
    IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
    INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
    NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
    DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
    THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
    (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
    THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#ifndef _MIO_DNS_H_
#define _MIO_DNS_H_

#include <mio.h>

#define MIO_DNS_PORT (53)

enum mio_dns_opcode_t
{
	MIO_DNS_OPCODE_QUERY = 0, /* standard query */
	MIO_DNS_OPCODE_IQUERY = 1, /* inverse query */
	MIO_DNS_OPCODE_STATUS = 2, /* status request */
	/* 3 unassigned */
	MIO_DNS_OPCODE_NOTIFY = 4,
	MIO_DNS_OPCODE_UPDATE = 5
};
typedef enum mio_dns_opcode_t mio_dns_opcode_t;

enum mio_dns_rcode_t
{
	MIO_DNS_RCODE_NOERROR   = 0,
	MIO_DNS_RCODE_FORMERR   = 1,  /* format error */
	MIO_DNS_RCODE_SERVFAIL  = 2,  /* server failure */
	MIO_DNS_RCODE_NXDOMAIN  = 3,  /* non-existent domain */
	MIO_DNS_RCODE_NOTIMPL   = 4,  /* not implemented */
	MIO_DNS_RCODE_REFUSED   = 5,  /* query refused */
	MIO_DNS_RCODE_YXDOMAIN  = 6,  /* name exists when it should not */
	MIO_DNS_RCODE_YXRRSET   = 7,  /* RR set exists when it should not */
	MIO_DNS_RCODE_NXRRSET   = 8,  /* RR set exists when it should not */
	MIO_DNS_RCODE_NOTAUTH   = 9,  /* not authorized or server not authoritative for zone*/
	MIO_DNS_RCODE_NOTZONE   = 10, /* name not contained in zone */
	MIO_DNS_RCODE_BADVERS   = 16,
	MIO_DNS_RCODE_BADSIG    = 17,
	MIO_DNS_RCODE_BADTIME   = 18,
	MIO_DNS_RCODE_BADMODE   = 19,
	MIO_DNS_RCODE_BADNAME   = 20,
	MIO_DNS_RCODE_BADALG    = 21,
	MIO_DNS_RCODE_BADTRUNC  = 22,
	MIO_DNS_RCODE_BADCOOKIE = 23
};
typedef enum mio_dns_rcode_t mio_dns_rcode_t;

enum mio_dns_qtype_t
{
	MIO_DNS_QTYPE_A = 1,
	MIO_DNS_QTYPE_NS = 2,
	MIO_DNS_QTYPE_CNAME = 5,
	MIO_DNS_QTYPE_SOA = 6,
	MIO_DNS_QTYPE_NULL = 10,
	MIO_DNS_QTYPE_PTR = 12,
	MIO_DNS_QTYPE_MX = 15,
	MIO_DNS_QTYPE_TXT = 16,
	MIO_DNS_QTYPE_AAAA = 28,
	MIO_DNS_QTYPE_EID = 31,
	MIO_DNS_QTYPE_SRV = 33,
	MIO_DNS_QTYPE_OPT = 41,
	MIO_DNS_QTYPE_RRSIG = 46,
	MIO_DNS_QTYPE_AFXR = 252, /* entire zone transfer */
	MIO_DNS_QTYPE_ANY = 255
};
typedef enum mio_dns_qtype_t mio_dns_qtype_t;

enum mio_dns_qclass_t
{
	MIO_DNS_QCLASS_IN = 1, /* internet */
	MIO_DNS_QCLASS_CH = 3, /* chaos */
	MIO_DNS_QCLASS_HS = 4, /* hesiod */
	MIO_DNS_QCLASS_NONE = 254,
	MIO_DNS_QCLASS_ANY = 255
};
typedef enum mio_dns_qclass_t mio_dns_qclass_t;

enum mio_dns_eopt_code_t
{
	MIO_DNS_EOPT_NSID         = 3,
	MIO_DNS_EOPT_DAU          = 5,
	MIO_DNS_EOPT_DHU          = 6,
	MIO_DNS_EOPT_N3U          = 7,
	MIO_DNS_EOPT_ECS          = 8,
	MIO_DNS_EOPT_EXPIRE       = 9,
	MIO_DNS_EOPT_COOKIE       = 10,
	MIO_DNS_EOPT_TCPKEEPALIVE = 11,
	MIO_DNS_EOPT_PADDING      = 12,
	MIO_DNS_EOPT_CHAIN        = 13,
	MIO_DNS_EOPT_KEYTAG       = 14,
};
typedef enum mio_dns_eopt_code_t mio_dns_eopt_code_t;

/* dns message preamble */
typedef struct mio_dns_msg_t mio_dns_msg_t;
struct mio_dns_msg_t
{
	mio_oow_t      buflen;
	mio_oow_t      pktlen;
	mio_tmridx_t   rtmridx;
	mio_dev_t*     dev;
	mio_dns_msg_t* prev;
	mio_dns_msg_t* next;
};

#include <mio-pac1.h>
struct mio_dns_pkt_t /* dns packet header */
{
	mio_uint16_t id;
#if defined(MIO_ENDIAN_BIG)
	mio_uint16_t qr: 1; /* query(0), answer(1) */
	mio_uint16_t opcode: 4; /* operation type */
	mio_uint16_t aa: 1; /* authoritative answer */
	mio_uint16_t tc: 1; /* truncated. response too large for UDP */
	mio_uint16_t rd: 1; /* recursion desired */

	mio_uint16_t ra: 1; /* recursion available */
	mio_uint16_t unused_1: 1;
	mio_uint16_t ad: 1; /* authentication data - dnssec */
	mio_uint16_t cd: 1; /* checking disabled - dnssec */
	mio_uint16_t rcode: 4; /* reply code - for reply only */
#else
	mio_uint16_t rd: 1;
	mio_uint16_t tc: 1;
	mio_uint16_t aa: 1;
	mio_uint16_t opcode: 4;
	mio_uint16_t qr: 1;

	mio_uint16_t rcode: 4;
	mio_uint16_t cd: 1;
	mio_uint16_t ad: 1;
	mio_uint16_t unused_1: 1;
	mio_uint16_t ra: 1;
#endif

	mio_uint16_t qdcount; /* number of questions */
	mio_uint16_t ancount; /* number of answers (answer part) */
	mio_uint16_t nscount; /* number of name servers (authority part. only NS types) */
	mio_uint16_t arcount; /* number of additional resource (additional part) */
};
typedef struct mio_dns_pkt_t mio_dns_pkt_t;

struct mio_dns_pkt_alt_t
{
	mio_uint16_t id;
	mio_uint16_t flags;
	mio_uint16_t rrcount[4];
};
typedef struct mio_dns_pkt_alt_t mio_dns_pkt_alt_t;
/* question
 *   name, qtype, qclass
 * answer
 *   name, qtype, qclass, ttl, rlength, rdata
 */

/* trailing part after the domain name in a resource record in a question */
struct mio_dns_qrtr_t
{
	/* qname upto 64 bytes */
	mio_uint16_t qtype;
	mio_uint16_t qclass;
};
typedef struct mio_dns_qrtr_t mio_dns_qrtr_t;

/* trailing part after the domain name in a resource record in an answer */
struct mio_dns_rrtr_t
{
	/* qname upto 64 bytes */
	mio_uint16_t qtype;
	mio_uint16_t qclass;
	mio_uint32_t ttl;
	mio_uint16_t dlen; /* data length */
	/* actual data if if dlen > 0 */
};
typedef struct mio_dns_rrtr_t mio_dns_rrtr_t;

struct mio_dns_eopt_t
{
	mio_uint16_t code;
	mio_uint16_t dlen;
	/* actual data if if dlen > 0 */
};
typedef struct mio_dns_eopt_t mio_dns_eopt_t;

#include <mio-upac.h>

typedef struct mio_dnss_t mio_dnss_t;
typedef struct mio_dnsc_t mio_dnsc_t;

/*
#define MIO_DNS_HDR_MAKE_FLAGS(qr,opcode,aa,tc,rd,ra,ad,cd,rcode) \
	((((qr) & 0x01) << 15) | (((opcode) & 0x0F) << 14) | (((aa) & 0x01) << 10) | (((tc) & 0x01) << 9) | \
	(((rd) & 0x01) << 8) | (((ra) & 0x01) << 7) | (((ad) & 0x01) << 5) | (((cd) & 0x01) << 4) | ((rcode) & 0x0F))
*/

/* breakdown of the dns message id and flags */
struct mio_dns_bdns_t
{
	int id; /* auto-assign if negative. */

	mio_uint8_t qr; /* query(0), answer(1) */
	mio_uint8_t opcode; /* operation type */
	mio_uint8_t aa; /* authoritative answer */
	mio_uint8_t tc; /* truncated. response too large for UDP */
	mio_uint8_t rd; /* recursion desired */

	mio_uint8_t ra; /* recursion available */
	mio_uint8_t ad; /* authentication data - dnssec */
	mio_uint8_t cd; /* checking disabled - dnssec */
	mio_uint8_t rcode; /* reply code - for reply only */
};
typedef struct mio_dns_bdns_t mio_dns_bdns_t;

/* breakdown of question record */
struct mio_dns_bqr_t
{
	mio_bch_t*   qname;
	mio_uint16_t qtype;
	mio_uint16_t qclass;
};
typedef struct mio_dns_bqr_t mio_dns_bqr_t;


enum mio_dns_rr_part_t
{
	MIO_DNS_RR_PART_ANSWER,
	MIO_DNS_RR_PART_AUTHORITY,
	MIO_DNS_RR_PART_ADDITIONAL
};
typedef enum mio_dns_rr_part_t mio_dns_rr_part_t;

/* breakdown of resource record */
struct mio_dns_brr_t
{
	mio_dns_rr_part_t  part;
	mio_bch_t*         qname;
	mio_uint16_t       qtype;
	mio_uint16_t       qclass;
	mio_uint32_t       ttl;
	mio_uint16_t       dlen;
	void*              dptr;
};
typedef struct mio_dns_brr_t mio_dns_brr_t;

#if 0
/* A RDATA */
struct mio_dns_brd_a_t 
{
};
typedef struct mio_dns_brd_a_t mio_dns_brd_a_t;

/* 3.3.1 CNAME RDATA format */
struct mio_dns_brd_cname_t
{
};
typedef struct mio_dns_brd_cname_t mio_dns_brc_cname_t;


/* 3.3.9 MX RDATA format */
struct mio_dns_brd_mx_t
{
	mio_uint16_t preference;
	mio_bch_t*   exchange;
};
typedef struct mio_dns_brd_mx_t mio_dns_brd_mx_t;



struct mio_dns_brd_soa_t
{
	mio_bch_t*   mname;
	mio_bch_t*   rname; 
	mio_uint32_t serial
	mio_uint32_t refresh;
	mio_uint32_t retry;
	mio_uint32_t expire;
	mio_uint32_t minimum;
};
typedef struct mio_dns_brd_soa_t mio_dns_brd_soa_t;
#endif

struct mio_dns_beopt_t
{
	mio_uint16_t code;
	mio_uint16_t dlen;
	void*        dptr;
};
typedef struct mio_dns_beopt_t mio_dns_beopt_t;

/* the full rcode must be given. the macro takes the upper 8 bits */
#define MIO_DNS_EDNS_MAKE_TTL(rcode,version,dnssecok) ((((((mio_uint32_t)rcode) >> 4) & 0xFF) << 24) | (((mio_uint32_t)version & 0xFF) << 16) | (((mio_uint32_t)dnssecok & 0x1) << 15))

struct mio_dns_bedns_t
{
	mio_uint16_t     uplen; /* udp payload len - will be placed in the qclass field of RR. */

	/* the ttl field(32 bits) of RR holds extended rcode, version, dnssecok */
	mio_uint8_t      version; 
	mio_uint8_t      dnssecok;

	mio_oow_t        beonum; /* option count */
	mio_dns_beopt_t* beoptr;
};
typedef struct mio_dns_bedns_t mio_dns_bedns_t;

#if defined(__cplusplus)
extern "C" {
#endif

MIO_EXPORT mio_dnsc_t* mio_dnsc_start (
	mio_t* mio
);

MIO_EXPORT void mio_dnsc_stop (
	mio_dnsc_t* dnsc
);

MIO_EXPORT int mio_dnsc_sendreq (
	mio_dnsc_t*      dnsc,
	mio_dns_bdns_t*  bdns,
	mio_dns_bqr_t*   qr,
	mio_oow_t        qr_count,
	mio_dns_bedns_t* edns
);

MIO_EXPORT int mio_dnsc_sendmsg (
	mio_dnsc_t*      dnsc,
	mio_dns_bdns_t*  bdns,
	mio_dns_bqr_t*   qr,
	mio_oow_t        qr_count,
	mio_dns_brr_t*   rr,
	mio_oow_t        rr_count,
	mio_dns_bedns_t* edns
);

#if defined(__cplusplus)
}
#endif

#endif