dns.h

/* Copyright (c) 2006-2012, DNSPod Inc.
 * 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 COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS 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.

 * The views and conclusions contained in the software and documentation are those
 * of the authors and should not be interpreted as representing official policies, 
 * either expressed or implied, of the FreeBSD Project.
 */


#ifndef _DNS_H
#define _DNS_H

#include "storage.h"
#include "net.h"
#include "datas.h"


//-------------SYSTEM LIMIT----------------------
#define MAX_LABEL_LEN (63)
#define MAX_DOMAIN_LEN (255)
#define MIN_MSG_LEN (sizeof(dnsheader) + sizeof(qdns))
//a.b.c.d...15
#define MAX_NS_LVL (16)
#define MAX_UDP_SIZE (512)
//addr to auth.
#define MAX_PAR (7)
#define MAX_RR_NUM (1000)
//query to para_num auth servers
#define PARA_NUM (3)
//-----------------------------------------------



//  header
//  question
//  answer
//  authority
//  additional

//header format
/////////////
//id
//flag(qr:1,opcode:4,aa:1,tc:1,rd:1,ra:1,z:3,rcode:4)
//qdcount
//ancount
//nscount
//arcount
/////////////

//question format
////////////
//name //digit,char,hyphen
//type
//class
////////////

//rr format
////////////
//name
//type
//class
//ttl
//rdlength
//data
////////////


enum 
{
 NO_ERROR = 0,
 FORMAT_ERROR = 1,
 SERVER_FAIL = 2,
 NAME_ERROR = 3,
 NOT_IMPL = 4,
 REFUSED = 5,
};


enum
{
 MAX_TRY_TIMES = 15,
 IP_DATA_LEN = 2000,
};


//0 is q,1 is r
#define QR_Q (0)
#define QR_R (1)
#define GET_QR(flag) ((flag & 0x8000) / 0x8000)
#define SET_QR_R(flag) (flag | 0x8000)
#define SET_QR_Q(flag) (flag & 0x7fff)
#define GET_OPCODE(flag) ((flag & 7800) >> 11)
//we always set opcode 0 at current veserion.
#define QUERY (0)
#define IQUERY (1)
#define STATUS (2)
#define GET_AA(flag) ((flag & 0x0400) / 0x0400)
#define SET_AA(flag) (flag | 0x0400)
#define GET_TC(flag) ((flag & 0x0200) / 0x0200)
#define SET_TC(flag) (flag | 0x0200)
#define GET_RD(flag) ((flag & 0x0100) / 0x0100)
#define SET_RA(flag) (flag | 0x0080)
#define GET_ERROR(flag) (flag & 0x7)
#define SET_ERROR(flag,errcode) (flag & 0xfff0 + errcode)
#define IS_PTR(os) (os >= 0xc000 && os <= 0xcfff) //in reply msg
#define GET_OFFSET(offset) (offset & 0x3fff) //the 2 higher bits set to 0
#define SET_OFFSET(offset) (offset | 0xc000)
#define IS_EDNS0(flag) (flag > 0x4000 && flag < 0x4fff)


//only IN support
enum
{
 CLASS_IN = 1,
};


struct setheader
{
 ushort an;
 ushort ns;
 ushort id;
 uchar *od;
 uchar *itor;
 ushort type;
};



enum
{
 AN_SECTION = 2,
 NS_SECTION = 5,
 AR_SECTION = 7,
 DMS_SIZE = 256,
};


struct hlpp
{
 int *stype;
 struct htable *ds;
 struct rbtree *rbt;
 uchar *buf;
 int datalen;
 uchar *dms;
 int dmsidx;
 int section;
};


enum rrtype
{
 BEGIN_TYPE = 0, A = 1, NS = 2,
 MD = 3, MF = 4, CNAME = 5, SOA = 6,
 MB = 7, MG = 8, MR = 9, NUL = 10,
 WKS = 11, PTR = 12, HINFO = 13,
 MINFO = 14, MX = 15, TXT = 16,RP = 17,//rfc1183
 AFSDB = 18,//rfc1183
 /*gap*/SIG = 24, KEY = 25,//rfc2065
 /*gap*/AAAA = 28,/*gap*/ NXT = 30, //rfc2065
 /*gap*/SRV = 33, //rfc2782
 CERT = 37,//rfc4398
 /*gap*/A6 = 38, DNAME = 39,/*rfc2672*//*gap*/ OPT = 41, //for edns0
 APL = 42,/*rfc3123*/ DS = 43, //rfc3658
 /*gap*/RRSIG = 46,//rfc4034
 NSEC = 47, DNSKEY = 48,DHCID = 49,/*rfc4701*//*gap*/TKEY = 249,
 /*gap*/AXFR = 252, MAILB = 253,
 MAILA = 254,//obsolete
 ASTERISK = 255,//*,a request for all records
};


struct hlpc
{
 uchar *name;
 short off,level,ref,mt;
};


struct hlpf
{
 uint ttl;
 uchar *hdr;
 ushort type;
 uchar *from;
 uchar *to;
};


#pragma pack (1)
struct fillmsg
{
 uint16_t type;
 uint16_t dclass;
 uint32_t ttl;
 uint16_t len;
};
#pragma pack()


#define TYPE_RECORD (7)
#define TYPE_MSG_LINE (1000)
#define TYPE_TCP_MSG (1007)
#define TYPE_UDP_MSG (1009)

#pragma pack (1)
typedef struct tag_dnsheader
{
 uint16_t id,flags;
 uint16_t qdcount,ancount,nscount,arcount;
}dnsheader;
#pragma pack ()


#pragma pack (1)
typedef struct tag_dq
{
 uint16_t type,dclass;
}qdns;
#pragma pack ()


//some base information about dns msg
struct baseinfo
{
 enum rrtype type;
 uchar *origindomain;
 int err;
 int dlen;
 ushort id;
};

#pragma pack (1)
struct soa
{
 uchar *mname;
 uchar *rname;
 uint32_t serial; //201102022222, 12334545
 uint32_t refresh,retry,expire,minimum;
};
#pragma pack ()

#pragma pack(1)
//_service._proto.name
//in struct record.data.
//uchar *service
//uchar *proto;
//service and proto are NOT case sensitive.
struct srv
{
 uint16_t pri,wei,port;
 //uchar *target;
//name compression is not to be used for this field
};
#pragma pack()


enum
{
 MOST_TRY_PER_QUERY = 3,
};


//query from auth server
#define QBUFFER_SIZE (256)
struct qoutinfo
{
 //client info
 uchar *td; //type and domain
 struct sockinfo *cli; //sock info
 ushort cid,dlen;//include 0
 ushort lables;
 //query info
 uchar *qing;
 ushort backid;
 ushort aid,mask; //auth id,domain mask
 ushort qname;
 //status info
 ushort sq; //send query flag
 ushort qtimes; //ns,cname,domain
 ushort socktype,stat; //this may be diffefrent from client's socktype
 uchar qbuffer[QBUFFER_SIZE];
 ushort hascname;
 int tcpfd;
 int tcpnums;
 int mxtry;
 int qns;
 uint stime;
};


enum
{
 Q_CNAME = 3,
 Q_DOMAIN = 4,
 Q_NS = 6,
};


int find_addr(struct htable *fwd,struct htable*,struct qoutinfo*,uchar*);


uchar *fill_header_in_msg(struct setheader*);
uchar *fill_rrset_in_msg(struct hlpc*,uchar*,uchar*,int,uchar*,uint16_t*);

uint dname_hash(void*);

int check_out_msg(ushort,uchar*,int);
int check_an_msg(ushort,uchar*,int*);
int check_dns_name(uchar *domain,int*);
int check_domain_mask(uchar*,uchar*);

int make_dns_msg_for_new(uchar*,ushort,uchar*,ushort);
int send_tc_to_client(uchar*,struct sockinfo*,ushort);

uchar* str_to_len_label(uchar *domain,int len);

int get_domain_from_msg(uchar *label,uchar *b,uchar *tmpd);
int get_dns_info(uchar*,ushort*,ushort*,uint*,ushort*);
int get_level(uchar*);
int make_type_domain(uchar *domain,int dlen,int type,uchar *buffer);
int insert_kv_mem(struct rbtree *,struct htable *ds,uchar *k,uchar *v,int vlen);

uchar *fill_a_record_in_msg(struct hlpc *h,uchar *from,uchar *to,uint ttl);
uchar *fill_name_in_msg(struct hlpc *h,uchar *to,int idx);
uchar *fill_header_in_msg(struct setheader *sh);
int fill_rrset_in_buffer(uchar*,uchar*,uchar*,int,int,struct hlpp*);
int transfer_record_to_msg(uchar*,uchar *td,uchar *buf,int buflen,uint16_t*);

struct baseinfo passer_dns_data(struct sockinfo*);
uchar* process_rdata(struct hlpp*,uchar *,int);

int check_qo(struct qoutinfo *qo);
uchar* dbg_print_label(uchar *label,int visible);
uchar* dbg_print_domain(uchar *hdr,uchar *itor);
void dbg_print_ip(uchar *ip,enum rrtype type);
int dbg_print_td(uchar *td);

#endif