/*
  * $Id$
  *
  * resolver related functions

  *
  * Copyright (C) 2001-2003 Fhg Fokus
  *
  * This file is part of ser, a free SIP server.
  *
  * ser is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
  * the Free Software Foundation; either version 2 of the License, or
  * (at your option) any later version
  *
  * For a license to use the ser software under conditions
  * other than those described here, or to purchase support for this
  * software, please contact iptel.org by e-mail at the following addresses:
  *    info@iptel.org
  *
  * ser is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  * GNU General Public License for more details.
  *
  * You should have received a copy of the GNU General Public License 
  * along with this program; if not, write to the Free Software 
  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

  */

 /* History:
  * --------
  *  2003-04-12  support for resolving ipv6 address references added (andrei)
  */

 #ifndef __resolve_h
 #define __resolve_h

 #include <sys/types.h>
 #include <sys/socket.h>

 #include <netdb.h>

 #include <arpa/nameser.h>

 #include "ip_addr.h"
 

 #define MAX_QUERY_SIZE 8192
 #define ANS_SIZE       8192
 #define DNS_HDR_SIZE     12
 #define MAX_DNS_NAME 256

 #define MAX_DNS_STRING 255

 /* query union*/
 union dns_query{
 	HEADER hdr;
 	unsigned char buff[MAX_QUERY_SIZE];
 };
 
 
 /* rdata struct*/
 struct rdata {
 	unsigned short type;
 	unsigned short class;
 	unsigned int   ttl;
 	void* rdata;
 	struct rdata* next;
 };
 
 
 /* srv rec. struct*/
 struct srv_rdata {
 	unsigned short priority;
 	unsigned short weight;
 	unsigned short port;
 	unsigned int name_len;
 	char name[MAX_DNS_NAME];
 };
 

 /* naptr rec. struct*/
 struct naptr_rdata {
 	unsigned short order;
 	unsigned short pref;
 	unsigned int flags_len;
 	char flags[MAX_DNS_STRING];
 	unsigned int services_len;
 	char services[MAX_DNS_STRING];
 	unsigned int regexp_len;
 	char regexp[MAX_DNS_STRING];
 	unsigned int repl_len; /* not currently used */
 	char repl[MAX_DNS_NAME];
 };
 

 
 /* A rec. struct */
 struct a_rdata {
 	unsigned char ip[4];
 };
 
 struct aaaa_rdata {
 	unsigned char ip6[16];
 };
 

 /* cname rec. struct*/
 struct cname_rdata {
 	char name[MAX_DNS_NAME];
 };
 

 
 
 struct rdata* get_record(char* name, int type);
 void free_rdata_list(struct rdata* head);
 
 

 #define rev_resolvehost(ip)\
 					gethostbyaddr((char*)(ip)->u.addr, (ip)->len, (ip)->af);

 
 #define HEX2I(c) \
 	(	(((c)>='0') && ((c)<='9'))? (c)-'0' :  \
 		(((c)>='A') && ((c)<='F'))? ((c)-'A')+10 : \
 		(((c)>='a') && ((c)<='f'))? ((c)-'a')+10 : -1 )
 
 

 /* converts a str to an ipv4 address, returns the address or 0 on error
    Warning: the result is a pointer to a statically allocated structure */

 static inline struct ip_addr* str2ip(str* st)

 {
 	int i;
 	unsigned char *limit;
 	static struct ip_addr ip;

 	unsigned char* s;
 

 	s=(unsigned char*)st->s;

 
 	/*init*/
 	ip.u.addr32[0]=0;
 	i=0;

 	limit=(unsigned char*)(st->s + st->len);

 	for(;s<limit ;s++){
 		if (*s=='.'){

 				i++;
 				if (i>3) goto error_dots;

 		}else if ( (*s <= '9' ) && (*s >= '0') ){
 				ip.u.addr[i]=ip.u.addr[i]*10+*s-'0';

 		}else{
 				//error unknown char
 				goto error_char;
 		}
 	}
 	ip.af=AF_INET;
 	ip.len=4;
 	
 	return &ip;
 error_dots:

 	DBG("str2ip: ERROR: too many dots in [%.*s]\n", st->len, st->s);

 	return 0;

  error_char:

 	/*

 	DBG("str2ip: WARNING: unexpected char %c in [%.*s]\n", *s, st->len, st->s);

 	*/

 	return 0;
 }
 
 
 
 /* returns an ip_addr struct.; on error returns 0
  * the ip_addr struct is static, so subsequent calls will destroy its content*/

 static inline struct ip_addr* str2ip6(str* st)

 {
 	int i, idx1, rest;
 	int no_colons;
 	int double_colon;
 	int hex;
 	static struct ip_addr ip;
 	unsigned short* addr_start;
 	unsigned short addr_end[8];
 	unsigned short* addr;
 	unsigned char* limit;

 	unsigned char* s;

 	
 	/* init */

 	if ((st->len) && (st->s[0]=='[')){
 		/* skip over [ ] */
 		if (st->s[st->len-1]!=']') goto error_char;
 		s=(unsigned char*)(st->s+1);
 		limit=(unsigned char*)(st->s+st->len-1);
 	}else{
 		s=(unsigned char*)st->s;
 		limit=(unsigned char*)(st->s+st->len);
 	}

 	i=idx1=rest=0;
 	double_colon=0;
 	no_colons=0;
 	ip.af=AF_INET6;
 	ip.len=16;
 	addr_start=ip.u.addr16;
 	addr=addr_start;
 	memset(addr_start, 0 , 8*sizeof(unsigned short));
 	memset(addr_end, 0 , 8*sizeof(unsigned short));

 	for (; s<limit; s++){
 		if (*s==':'){

 			no_colons++;
 			if (no_colons>7) goto error_too_many_colons;
 			if (double_colon){
 				idx1=i;
 				i=0;
 				if (addr==addr_end) goto error_colons;
 				addr=addr_end;
 			}else{
 				double_colon=1;

 				addr[i]=htons(addr[i]);

 				i++;
 			}

 		}else if ((hex=HEX2I(*s))>=0){

 				addr[i]=addr[i]*16+hex;
 				double_colon=0;
 		}else{
 			/* error, unknown char */
 			goto error_char;
 		}
 	}

 	if (no_colons<2) goto error_too_few_colons;
 	if (!double_colon){ /* not ending in ':' */
 		addr[i]=htons(addr[i]);
 		i++; 
 	}

 	/* if address contained '::' fix it */
 	if (addr==addr_end){
 		rest=8-i-idx1;
 		memcpy(addr_start+idx1+rest, addr_end, i*sizeof(unsigned short));
 	}
 /*
 	DBG("str2ip6: idx1=%d, rest=%d, no_colons=%d, hex=%x\n",
 			idx1, rest, no_colons, hex);
 	DBG("str2ip6: address %x:%x:%x:%x:%x:%x:%x:%x\n", 
 			addr_start[0], addr_start[1], addr_start[2],
 			addr_start[3], addr_start[4], addr_start[5],
 			addr_start[6], addr_start[7] );
 */

 	return &ip;
 
 error_too_many_colons:

 	DBG("str2ip6: ERROR: too many colons in [%.*s]\n", st->len, st->s);

 	return 0;
 
 error_too_few_colons:

 	DBG("str2ip6: ERROR: too few colons in [%.*s]\n", st->len, st->s);

 	return 0;
 
 error_colons:

 	DBG("str2ip6: ERROR: too many double colons in [%.*s]\n", st->len, st->s);

 	return 0;
 
 error_char:

 	/*

 	DBG("str2ip6: WARNING: unexpected char %c in  [%.*s]\n", *s, st->len,

 			st->s);*/

 	return 0;
 }

 struct hostent* sip_resolvehost(str* name, unsigned short* port, int proto);

 
 
 
 /* gethostbyname wrappers
  * use this, someday they will use a local cache */
 

 static inline struct hostent* resolvehost(char* name)

 {

 	static struct hostent* he=0;

 #ifdef HAVE_GETIPNODEBYNAME 

 	int err;

 	static struct hostent* he2=0;

 #endif

 #ifndef DNS_IP_HACK
 	int len;
 #endif

 #ifdef DNS_IP_HACK
 	struct ip_addr* ip;

 	str s;
 
 	s.s = (char*)name;
 	s.len = strlen(name);
 

 	/* check if it's an ip address */

 	if ( ((ip=str2ip(&s))!=0)

 #ifdef	USE_IPV6

 		  || ((ip=str2ip6(&s))!=0)

 #endif
 		){
 		/* we are lucky, this is an ip address */

 		return ip_addr2he(&s, ip);

 	}
 	

 #else /* DNS_IP_HACK */
 	len=0;
 	if (*name=='['){
 		len=strlen(name);
 		if (len && (name[len-1]==']')){
 			name[len-1]=0; /* remove '[' */
 			name++; /* skip '[' */
 			goto skip_ipv4;
 		}
 	}

 #endif

 	/* ipv4 */
 	he=gethostbyname(name);

 #ifdef USE_IPV6
 	if(he==0){

 #ifndef DNS_IP_HACK
 skip_ipv4:
 #endif

 		/*try ipv6*/

 	#ifdef HAVE_GETHOSTBYNAME2
 		he=gethostbyname2(name, AF_INET6);
 	#elif defined HAVE_GETIPNODEBYNAME

 		/* on solaris 8 getipnodebyname has a memory leak,
 		 * after some time calls to it will fail with err=3
 		 * solution: patch your solaris 8 installation */
 		if (he2) freehostent(he2);
 		he=he2=getipnodebyname(name, AF_INET6, 0, &err);

 	#else

 		#error neither gethostbyname2 or getipnodebyname present

 	#endif

 #ifndef DNS_IP_HACK
 		if (len) name[len-2]=']'; /* restore */
 #endif

 	}
 #endif
 	return he;
 }

 #endif