src/rfc1035.c

/* dnsmasq is Copyright (c) 2000-2021 Simon Kelley

   This program 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; version 2 dated June, 1991, or
   (at your option) version 3 dated 29 June, 2007.
 
   This program 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, see <http://www.gnu.org/licenses/>.
*/

#include "dnsmasq.h"

int extract_name(struct dns_header *header, size_t plen, unsigned char **pp, 
		 char *name, int isExtract, int extrabytes)
{
  unsigned char *cp = (unsigned char *)name, *p = *pp, *p1 = NULL;
  unsigned int j, l, namelen = 0, hops = 0;
  int retvalue = 1;
  
  if (isExtract)
    *cp = 0;

  while (1)
    { 
      unsigned int label_type;

      if (!CHECK_LEN(header, p, plen, 1))
	return 0;
      
      if ((l = *p++) == 0) 
	/* end marker */
	{
	  /* check that there are the correct no. of bytes after the name */
	  if (!CHECK_LEN(header, p1 ? p1 : p, plen, extrabytes))
	    return 0;
	  
	  if (isExtract)
	    {
	      if (cp != (unsigned char *)name)
		cp--;
	      *cp = 0; /* terminate: lose final period */
	    }
	  else if (*cp != 0)
	    retvalue = 2;
	  
	  if (p1) /* we jumped via compression */
	    *pp = p1;
	  else
	    *pp = p;
	  
	  return retvalue;
	}

      label_type = l & 0xc0;
      
      if (label_type == 0xc0) /* pointer */
	{ 
	  if (!CHECK_LEN(header, p, plen, 1))
	    return 0;
	      
	  /* get offset */
	  l = (l&0x3f) << 8;
	  l |= *p++;
	  
	  if (!p1) /* first jump, save location to go back to */
	    p1 = p;
	      
	  hops++; /* break malicious infinite loops */
	  if (hops > 255)
	    return 0;
	  
	  p = l + (unsigned char *)header;
	}
      else if (label_type == 0x00)
	{ /* label_type = 0 -> label. */
	  namelen += l + 1; /* include period */
	  if (namelen >= MAXDNAME)
	    return 0;
	  if (!CHECK_LEN(header, p, plen, l))
	    return 0;
	  
	  for(j=0; j<l; j++, p++)
	    if (isExtract)
	      {
		unsigned char c = *p;
#ifdef HAVE_DNSSEC
		if (option_bool(OPT_DNSSEC_VALID))
		  {
		    if (c == 0 || c == '.' || c == NAME_ESCAPE)
		      {
			*cp++ = NAME_ESCAPE;
			*cp++ = c+1;
		      }
		    else
		      *cp++ = c; 
		  }
		else
#endif
		if (c != 0 && c != '.')
		  *cp++ = c;
		else
		  return 0;
	      }
	    else 
	      {
		unsigned char c1 = *cp, c2 = *p;
		
		if (c1 == 0)
		  retvalue = 2;
		else 
		  {
		    cp++;
		    if (c1 >= 'A' && c1 <= 'Z')
		      c1 += 'a' - 'A';
#ifdef HAVE_DNSSEC
		    if (option_bool(OPT_DNSSEC_VALID) && c1 == NAME_ESCAPE)
		      c1 = (*cp++)-1;
#endif
		    
		    if (c2 >= 'A' && c2 <= 'Z')
		      c2 += 'a' - 'A';
		     
		    if (c1 != c2)
		      retvalue =  2;
		  }
	      }
	    
	  if (isExtract)
	    *cp++ = '.';
	  else if (*cp != 0 && *cp++ != '.')
	    retvalue = 2;
	}
      else
	return 0; /* label types 0x40 and 0x80 not supported */
    }
}
 
/* Max size of input string (for IPv6) is 75 chars.) */
#define MAXARPANAME 75
int in_arpa_name_2_addr(char *namein, union all_addr *addrp)
{
  int j;
  char name[MAXARPANAME+1], *cp1;
  unsigned char *addr = (unsigned char *)addrp;
  char *lastchunk = NULL, *penchunk = NULL;
  
  if (strlen(namein) > MAXARPANAME)
    return 0;

  memset(addrp, 0, sizeof(union all_addr));

  /* turn name into a series of asciiz strings */
  /* j counts no. of labels */
  for(j = 1,cp1 = name; *namein; cp1++, namein++)
    if (*namein == '.')
      {
	penchunk = lastchunk;
        lastchunk = cp1 + 1;
	*cp1 = 0;
	j++;
      }
    else
      *cp1 = *namein;
  
  *cp1 = 0;

  if (j<3)
    return 0;

  if (hostname_isequal(lastchunk, "arpa") && hostname_isequal(penchunk, "in-addr"))
    {
      /* IP v4 */
      /* address arrives as a name of the form
	 www.xxx.yyy.zzz.in-addr.arpa
	 some of the low order address octets might be missing
	 and should be set to zero. */
      for (cp1 = name; cp1 != penchunk; cp1 += strlen(cp1)+1)
	{
	  /* check for digits only (weeds out things like
	     50.0/24.67.28.64.in-addr.arpa which are used 
	     as CNAME targets according to RFC 2317 */
	  char *cp;
	  for (cp = cp1; *cp; cp++)
	    if (!isdigit((unsigned char)*cp))
	      return 0;
	  
	  addr[3] = addr[2];
	  addr[2] = addr[1];
	  addr[1] = addr[0];
	  addr[0] = atoi(cp1);
	}

      return F_IPV4;
    }
  else if (hostname_isequal(penchunk, "ip6") && 
	   (hostname_isequal(lastchunk, "int") || hostname_isequal(lastchunk, "arpa")))
    {
      /* IP v6:
         Address arrives as 0.1.2.3.4.5.6.7.8.9.a.b.c.d.e.f.ip6.[int|arpa]
    	 or \[xfedcba9876543210fedcba9876543210/128].ip6.[int|arpa]
      
	 Note that most of these the various representations are obsolete and 
	 left-over from the many DNS-for-IPv6 wars. We support all the formats
	 that we can since there is no reason not to.
      */

      if (*name == '\\' && *(name+1) == '[' && 
	  (*(name+2) == 'x' || *(name+2) == 'X'))
	{	  
	  for (j = 0, cp1 = name+3; *cp1 && isxdigit((unsigned char) *cp1) && j < 32; cp1++, j++)
	    {
	      char xdig[2];
	      xdig[0] = *cp1;
	      xdig[1] = 0;
	      if (j%2)
		addr[j/2] |= strtol(xdig, NULL, 16);
	      else
		addr[j/2] = strtol(xdig, NULL, 16) << 4;
	    }
	  
	  if (*cp1 == '/' && j == 32)
	    return F_IPV6;
	}
      else
	{
	  for (cp1 = name; cp1 != penchunk; cp1 += strlen(cp1)+1)
	    {
	      if (*(cp1+1) || !isxdigit((unsigned char)*cp1))
		return 0;
	      
	      for (j = sizeof(struct in6_addr)-1; j>0; j--)
		addr[j] = (addr[j] >> 4) | (addr[j-1] << 4);
	      addr[0] = (addr[0] >> 4) | (strtol(cp1, NULL, 16) << 4);
	    }
	  
	  return F_IPV6;
	}
    }
  
  return 0;
}

unsigned char *skip_name(unsigned char *ansp, struct dns_header *header, size_t plen, int extrabytes)
{
  while(1)
    {
      unsigned int label_type;
      
      if (!CHECK_LEN(header, ansp, plen, 1))
	return NULL;
      
      label_type = (*ansp) & 0xc0;

      if (label_type == 0xc0)
	{
	  /* pointer for compression. */
	  ansp += 2;	
	  break;
	}
      else if (label_type == 0x80)
	return NULL; /* reserved */
      else if (label_type == 0x40)
	{
	  /* Extended label type */
	  unsigned int count;
	  
	  if (!CHECK_LEN(header, ansp, plen, 2))
	    return NULL;
	  
	  if (((*ansp++) & 0x3f) != 1)
	    return NULL; /* we only understand bitstrings */
	  
	  count = *(ansp++); /* Bits in bitstring */
	  
	  if (count == 0) /* count == 0 means 256 bits */
	    ansp += 32;
	  else
	    ansp += ((count-1)>>3)+1;
	}
      else
	{ /* label type == 0 Bottom six bits is length */
	  unsigned int len = (*ansp++) & 0x3f;
	  
	  if (!ADD_RDLEN(header, ansp, plen, len))
	    return NULL;

	  if (len == 0)
	    break; /* zero length label marks the end. */
	}
    }

  if (!CHECK_LEN(header, ansp, plen, extrabytes))
    return NULL;
  
  return ansp;
}

unsigned char *skip_questions(struct dns_header *header, size_t plen)
{
  int q;
  unsigned char *ansp = (unsigned char *)(header+1);

  for (q = ntohs(header->qdcount); q != 0; q--)
    {
      if (!(ansp = skip_name(ansp, header, plen, 4)))
	return NULL;
      ansp += 4; /* class and type */
    }
  
  return ansp;
}

unsigned char *skip_section(unsigned char *ansp, int count, struct dns_header *header, size_t plen)
{
  int i, rdlen;
  
  for (i = 0; i < count; i++)
    {
      if (!(ansp = skip_name(ansp, header, plen, 10)))
	return NULL; 
      ansp += 8; /* type, class, TTL */
      GETSHORT(rdlen, ansp);
      if (!ADD_RDLEN(header, ansp, plen, rdlen))
	return NULL;
    }

  return ansp;
}

size_t resize_packet(struct dns_header *header, size_t plen, unsigned char *pheader, size_t hlen)
{
  unsigned char *ansp = skip_questions(header, plen);
    
  /* if packet is malformed, just return as-is. */
  if (!ansp)
    return plen;
  
  if (!(ansp = skip_section(ansp, ntohs(header->ancount) + ntohs(header->nscount) + ntohs(header->arcount),
			    header, plen)))
    return plen;
    
  /* restore pseudoheader */
  if (pheader && ntohs(header->arcount) == 0)
    {
      /* must use memmove, may overlap */
      memmove(ansp, pheader, hlen);
      header->arcount = htons(1);
      ansp += hlen;
    }

  return ansp - (unsigned char *)header;
}

/* is addr in the non-globally-routed IP space? */ 
int private_net(struct in_addr addr, int ban_localhost) 
{
  in_addr_t ip_addr = ntohl(addr.s_addr);

  return
    (((ip_addr & 0xFF000000) == 0x7F000000) && ban_localhost)  /* 127.0.0.0/8    (loopback) */ ||
    ((ip_addr & 0xFF000000) == 0x00000000)  /* RFC 5735 section 3. "here" network */ ||
    ((ip_addr & 0xFF000000) == 0x0A000000)  /* 10.0.0.0/8     (private)  */ ||
    ((ip_addr & 0xFFF00000) == 0xAC100000)  /* 172.16.0.0/12  (private)  */ ||
    ((ip_addr & 0xFFFF0000) == 0xC0A80000)  /* 192.168.0.0/16 (private)  */ ||
    ((ip_addr & 0xFFFF0000) == 0xA9FE0000)  /* 169.254.0.0/16 (zeroconf) */ ||
    ((ip_addr & 0xFFFFFF00) == 0xC0000200)  /* 192.0.2.0/24   (test-net) */ ||
    ((ip_addr & 0xFFFFFF00) == 0xC6336400)  /* 198.51.100.0/24(test-net) */ ||
    ((ip_addr & 0xFFFFFF00) == 0xCB007100)  /* 203.0.113.0/24 (test-net) */ ||
    ((ip_addr & 0xFFFFFFFF) == 0xFFFFFFFF)  /* 255.255.255.255/32 (broadcast)*/ ;
}

static int private_net6(struct in6_addr *a)
{
  return 
    IN6_IS_ADDR_UNSPECIFIED(a) || /* RFC 6303 4.3 */
    IN6_IS_ADDR_LOOPBACK(a) ||    /* RFC 6303 4.3 */
    IN6_IS_ADDR_LINKLOCAL(a) ||   /* RFC 6303 4.5 */
    ((unsigned char *)a)[0] == 0xfd ||   /* RFC 6303 4.4 */
    ((u32 *)a)[0] == htonl(0x20010db8); /* RFC 6303 4.6 */
}

static unsigned char *do_doctor(unsigned char *p, int count, struct dns_header *header, size_t qlen, char *name, int *doctored)
{
  int i, qtype, qclass, rdlen;

  for (i = count; i != 0; i--)
    {
      if (name && option_bool(OPT_LOG))
	{
	  if (!extract_name(header, qlen, &p, name, 1, 10))
	    return 0;
	}
      else if (!(p = skip_name(p, header, qlen, 10)))
	return 0; /* bad packet */
      
      GETSHORT(qtype, p); 
      GETSHORT(qclass, p);
      p += 4; /* ttl */
      GETSHORT(rdlen, p);
      
      if (qclass == C_IN && qtype == T_A)
	{
	  struct doctor *doctor;
	  struct in_addr addr;
	  
	  if (!CHECK_LEN(header, p, qlen, INADDRSZ))
	    return 0;
	  
	  /* alignment */
	  memcpy(&addr, p, INADDRSZ);
	  
	  for (doctor = daemon->doctors; doctor; doctor = doctor->next)
	    {
	      if (doctor->end.s_addr == 0)
		{
		  if (!is_same_net(doctor->in, addr, doctor->mask))
		    continue;
		}
	      else if (ntohl(doctor->in.s_addr) > ntohl(addr.s_addr) || 
		       ntohl(doctor->end.s_addr) < ntohl(addr.s_addr))
		continue;
	      
	      addr.s_addr &= ~doctor->mask.s_addr;
	      addr.s_addr |= (doctor->out.s_addr & doctor->mask.s_addr);
	      /* Since we munged the data, the server it came from is no longer authoritative */
	      header->hb3 &= ~HB3_AA;
	      *doctored = 1;
	      memcpy(p, &addr, INADDRSZ);
	      break;
	    }
	}
      else if (qtype == T_TXT && name && option_bool(OPT_LOG))
	{
	  unsigned char *p1 = p;
	  if (!CHECK_LEN(header, p1, qlen, rdlen))
	    return 0;
	  while ((p1 - p) < rdlen)
	    {
	      unsigned int i, len = *p1;
	      unsigned char *p2 = p1;
	      if ((p1 + len - p) >= rdlen)
	        return 0; /* bad packet */
	      /* make counted string zero-term  and sanitise */
	      for (i = 0; i < len; i++)
		{
		  if (!isprint((int)*(p2+1)))
		    break;
		  
		  *p2 = *(p2+1);
		  p2++;
		}
	      *p2 = 0;
	      my_syslog(LOG_INFO, "reply %s is %s", name, p1);
	      /* restore */
	      memmove(p1 + 1, p1, i);
	      *p1 = len;
	      p1 += len+1;
	    }
	}		  
      
      if (!ADD_RDLEN(header, p, qlen, rdlen))
	 return 0; /* bad packet */
    }
  
  return p; 
}

static int find_soa(struct dns_header *header, size_t qlen, char *name, int *doctored)
{
  unsigned char *p;
  int qtype, qclass, rdlen;
  unsigned long ttl, minttl = ULONG_MAX;
  int i, found_soa = 0;
  
  /* first move to NS section and find TTL from any SOA section */
  if (!(p = skip_questions(header, qlen)) ||
      !(p = do_doctor(p, ntohs(header->ancount), header, qlen, name, doctored)))
    return 0;  /* bad packet */
  
  for (i = ntohs(header->nscount); i != 0; i--)
    {
      if (!(p = skip_name(p, header, qlen, 10)))
	return 0; /* bad packet */
      
      GETSHORT(qtype, p); 
      GETSHORT(qclass, p);
      GETLONG(ttl, p);
      GETSHORT(rdlen, p);
      
      if ((qclass == C_IN) && (qtype == T_SOA))
	{
	  found_soa = 1;
	  if (ttl < minttl)
	    minttl = ttl;

	  /* MNAME */
	  if (!(p = skip_name(p, header, qlen, 0)))
	    return 0;
	  /* RNAME */
	  if (!(p = skip_name(p, header, qlen, 20)))
	    return 0;
	  p += 16; /* SERIAL REFRESH RETRY EXPIRE */
	  
	  GETLONG(ttl, p); /* minTTL */
	  if (ttl < minttl)
	    minttl = ttl;
	}
      else if (!ADD_RDLEN(header, p, qlen, rdlen))
	return 0; /* bad packet */
    }
  
  /* rewrite addresses in additional section too */
  if (!do_doctor(p, ntohs(header->arcount), header, qlen, NULL, doctored))
    return 0;
  
  if (!found_soa)
    minttl = daemon->neg_ttl;

  return minttl;
}

/* Note that the following code can create CNAME chains that don't point to a real record,
   either because of lack of memory, or lack of SOA records.  These are treated by the cache code as 
   expired and cleaned out that way. 
   Return 1 if we reject an address because it look like part of dns-rebinding attack. */
int extract_addresses(struct dns_header *header, size_t qlen, char *name, time_t now, 
		      char **ipsets, int is_sign, int check_rebind, int no_cache_dnssec,
		      int secure, int *doctored)
{
  unsigned char *p, *p1, *endrr, *namep;
  int i, j, qtype, qclass, aqtype, aqclass, ardlen, res, searched_soa = 0;
  unsigned long ttl = 0;
  union all_addr addr;
#ifdef HAVE_IPSET
  char **ipsets_cur;
#else
  (void)ipsets; /* unused */
#endif

  
  cache_start_insert();

  /* find_soa is needed for dns_doctor and logging side-effects, so don't call it lazily if there are any. */
  if (daemon->doctors || option_bool(OPT_LOG) || option_bool(OPT_DNSSEC_VALID))
    {
      searched_soa = 1;
      ttl = find_soa(header, qlen, name, doctored);

      if (*doctored)
	{
	  if (secure)
	    return 0;
#ifdef HAVE_DNSSEC
	  if (option_bool(OPT_DNSSEC_VALID))
	    for (i = 0; i < ntohs(header->ancount); i++)
	      if (daemon->rr_status[i] != 0)
		return 0;
#endif
	}
    }
  
  /* go through the questions. */
  p = (unsigned char *)(header+1);
  
  for (i = ntohs(header->qdcount); i != 0; i--)
    {
      int found = 0, cname_count = CNAME_CHAIN;
      struct crec *cpp = NULL;
      int flags = RCODE(header) == NXDOMAIN ? F_NXDOMAIN : 0;
#ifdef HAVE_DNSSEC
      int cname_short = 0;
#endif
      unsigned long cttl = ULONG_MAX, attl;

      namep = p;
      if (!extract_name(header, qlen, &p, name, 1, 4))
	return 0; /* bad packet */
           
      GETSHORT(qtype, p); 
      GETSHORT(qclass, p);
      
      if (qclass != C_IN)
	continue;

      /* PTRs: we chase CNAMEs here, since we have no way to 
	 represent them in the cache. */
      if (qtype == T_PTR)
	{ 
	  int name_encoding = in_arpa_name_2_addr(name, &addr);
	  
	  if (!name_encoding)
	    continue;

	  if (!(flags & F_NXDOMAIN))
	    {
	    cname_loop:
	      if (!(p1 = skip_questions(header, qlen)))
		return 0;
	      
	      for (j = 0; j < ntohs(header->ancount); j++) 
		{
		  int secflag = 0;
		  unsigned char *tmp = namep;
		  /* the loop body overwrites the original name, so get it back here. */
		  if (!extract_name(header, qlen, &tmp, name, 1, 0) ||
		      !(res = extract_name(header, qlen, &p1, name, 0, 10)))
		    return 0; /* bad packet */
		  
		  GETSHORT(aqtype, p1); 
		  GETSHORT(aqclass, p1);
		  GETLONG(attl, p1);
		  if ((daemon->max_ttl != 0) && (attl > daemon->max_ttl) && !is_sign)
		    {
		      (p1) -= 4;
		      PUTLONG(daemon->max_ttl, p1);
		    }
		  GETSHORT(ardlen, p1);
		  endrr = p1+ardlen;
		  
		  /* TTL of record is minimum of CNAMES and PTR */
		  if (attl < cttl)
		    cttl = attl;

		  if (aqclass == C_IN && res != 2 && (aqtype == T_CNAME || aqtype == T_PTR))
		    {
		      if (!extract_name(header, qlen, &p1, name, 1, 0))
			return 0;
#ifdef HAVE_DNSSEC
		      if (option_bool(OPT_DNSSEC_VALID) && daemon->rr_status[j] != 0)
			{
			  /* validated RR anywhere in CNAME chain, don't cache. */
			  if (cname_short || aqtype == T_CNAME)
			    return 0;

			  secflag = F_DNSSECOK;
			  /* limit TTL based on signature. */
			  if (daemon->rr_status[j] < cttl)
			    cttl = daemon->rr_status[j];
			}
#endif

		      if (aqtype == T_CNAME)
			{
			  if (!cname_count--)
			    return 0; /* looped CNAMES, we can't cache. */
#ifdef HAVE_DNSSEC
			  cname_short = 1;
#endif
			  goto cname_loop;
			}
		      
		      cache_insert(name, &addr, C_IN, now, cttl, name_encoding | secflag | F_REVERSE);
		      found = 1; 
		    }
		  
		  p1 = endrr;
		  if (!CHECK_LEN(header, p1, qlen, 0))
		    return 0; /* bad packet */
		}
	    }
	  
	   if (!found && !option_bool(OPT_NO_NEG))
	    {
	      if (!searched_soa)
		{
		  searched_soa = 1;
		  ttl = find_soa(header, qlen, NULL, doctored);
		}
	      if (ttl)
		cache_insert(NULL, &addr, C_IN, now, ttl, name_encoding | F_REVERSE | F_NEG | flags | (secure ?  F_DNSSECOK : 0));	
	    }
	}
      else
	{
	  /* everything other than PTR */
	  struct crec *newc;
	  int addrlen = 0;

	  if (qtype == T_A)
	    {
	      addrlen = INADDRSZ;
	      flags |= F_IPV4;
	    }
	  else if (qtype == T_AAAA)
	    {
	      addrlen = IN6ADDRSZ;
	      flags |= F_IPV6;
	    }
	  else if (qtype == T_SRV)
	    flags |= F_SRV;
	  else
	    continue;
	    
	cname_loop1:
	  if (!(p1 = skip_questions(header, qlen)))
	    return 0;
	  
	  for (j = 0; j < ntohs(header->ancount); j++) 
	    {
	      int secflag = 0;
	      
	      if (!(res = extract_name(header, qlen, &p1, name, 0, 10)))
		return 0; /* bad packet */
	      
	      GETSHORT(aqtype, p1); 
	      GETSHORT(aqclass, p1);
	      GETLONG(attl, p1);
	      if ((daemon->max_ttl != 0) && (attl > daemon->max_ttl) && !is_sign)
		{
		  (p1) -= 4;
		  PUTLONG(daemon->max_ttl, p1);
		}
	      GETSHORT(ardlen, p1);
	      endrr = p1+ardlen;
	      
	      if (aqclass == C_IN && res != 2 && (aqtype == T_CNAME || aqtype == qtype))
		{
#ifdef HAVE_DNSSEC
		  if (option_bool(OPT_DNSSEC_VALID) && daemon->rr_status[j] != 0)
		    {
		      secflag = F_DNSSECOK;

		      /* limit TTl based on sig. */
		      if (daemon->rr_status[j] < attl)
			attl = daemon->rr_status[j];
		    }
#endif		  
		  if (aqtype == T_CNAME)
		    {
		      if (!cname_count--)
			return 0; /* looped CNAMES */

		      if ((newc = cache_insert(name, NULL, C_IN, now, attl, F_CNAME | F_FORWARD | secflag)))
			{
			  newc->addr.cname.target.cache = NULL;
			  newc->addr.cname.is_name_ptr = 0; 
			  if (cpp)
			    {
			      next_uid(newc);
			      cpp->addr.cname.target.cache = newc;
			      cpp->addr.cname.uid = newc->uid;
			    }
			}
		      
		      cpp = newc;
		      if (attl < cttl)
			cttl = attl;
		      
		      namep = p1;
		      if (!extract_name(header, qlen, &p1, name, 1, 0))
			return 0;
		      
		      goto cname_loop1;
		    }
		  else if (!(flags & F_NXDOMAIN))
		    {
		      found = 1;
		      
		      if (flags & F_SRV)
			{
			   unsigned char *tmp = namep;

			   if (!CHECK_LEN(header, p1, qlen, 6))
			     return 0; /* bad packet */
			   GETSHORT(addr.srv.priority, p1);
			   GETSHORT(addr.srv.weight, p1);
			   GETSHORT(addr.srv.srvport, p1);
			   if (!extract_name(header, qlen, &p1, name, 1, 0))
			     return 0;
			   addr.srv.targetlen = strlen(name) + 1; /* include terminating zero */
			   if (!(addr.srv.target = blockdata_alloc(name, addr.srv.targetlen)))
			     return 0;
			   
			   /* we overwrote the original name, so get it back here. */
			   if (!extract_name(header, qlen, &tmp, name, 1, 0))
			     return 0;
			}
		      else
			{
			  /* copy address into aligned storage */
			  if (!CHECK_LEN(header, p1, qlen, addrlen))
			    return 0; /* bad packet */
			  memcpy(&addr, p1, addrlen);
		      
			  /* check for returned address in private space */
			  if (check_rebind)
			    {
			      if ((flags & F_IPV4) &&
				  private_net(addr.addr4, !option_bool(OPT_LOCAL_REBIND)))
				return 1;

			      /* Block IPv4-mapped IPv6 addresses in private IPv4 address space */
			      if (flags & F_IPV6)
				{
				  if (IN6_IS_ADDR_V4MAPPED(&addr.addr6))
				    {
				      struct in_addr v4;
				      v4.s_addr = ((const uint32_t *) (&addr.addr6))[3];
				      if (private_net(v4, !option_bool(OPT_LOCAL_REBIND)))
					return 1;
				    }

				  /* Check for link-local (LL) and site-local (ULA) IPv6 addresses */
				  if (IN6_IS_ADDR_LINKLOCAL(&addr.addr6) ||
				      IN6_IS_ADDR_SITELOCAL(&addr.addr6))
				    return 1;

				  /* Check for the IPv6 loopback address (::1) when
				     option rebind-localhost-ok is NOT set */
				  if (!option_bool(OPT_LOCAL_REBIND) &&
				      IN6_IS_ADDR_LOOPBACK(&addr.addr6))
				    return 1;
				}
			    }

#ifdef HAVE_IPSET
			  if (ipsets && (flags & (F_IPV4 | F_IPV6)))
			    {
			      ipsets_cur = ipsets;
			      while (*ipsets_cur)
				{
				  log_query((flags & (F_IPV4 | F_IPV6)) | F_IPSET, name, &addr, *ipsets_cur);
				  add_to_ipset(*ipsets_cur++, &addr, flags, 0);
				}
			    }
#endif
			}
		      
		      newc = cache_insert(name, &addr, C_IN, now, attl, flags | F_FORWARD | secflag);
		      if (newc && cpp)
			{
			  next_uid(newc);
			  cpp->addr.cname.target.cache = newc;
			  cpp->addr.cname.uid = newc->uid;
			}
		      cpp = NULL;
		    }
		}
	      
	      p1 = endrr;
	      if (!CHECK_LEN(header, p1, qlen, 0))
		return 0; /* bad packet */
	    }
	  
	  if (!found && !option_bool(OPT_NO_NEG))
	    {
	      if (!searched_soa)
		{
		  searched_soa = 1;
		  ttl = find_soa(header, qlen, NULL, doctored);
		}
	      /* If there's no SOA to get the TTL from, but there is a CNAME 
		 pointing at this, inherit its TTL */
	      if (ttl || cpp)
		{
		  newc = cache_insert(name, NULL, C_IN, now, ttl ? ttl : cttl, F_FORWARD | F_NEG | flags | (secure ? F_DNSSECOK : 0));	
		  if (newc && cpp)
		    {
		      next_uid(newc);
		      cpp->addr.cname.target.cache = newc;
		      cpp->addr.cname.uid = newc->uid;
		    }
		}
	    }
	}
    }
  
  /* Don't put stuff from a truncated packet into the cache.
     Don't cache replies from non-recursive nameservers, since we may get a 
     reply containing a CNAME but not its target, even though the target 
     does exist. */
  if (!(header->hb3 & HB3_TC) && 
      !(header->hb4 & HB4_CD) &&
      (header->hb4 & HB4_RA) &&
      !no_cache_dnssec)
    cache_end_insert();

  return 0;
}

/* If the packet holds exactly one query
   return F_IPV4 or F_IPV6  and leave the name from the query in name */
unsigned int extract_request(struct dns_header *header, size_t qlen, char *name, unsigned short *typep)
{
  unsigned char *p = (unsigned char *)(header+1);
  int qtype, qclass;

  if (typep)
    *typep = 0;

  if (ntohs(header->qdcount) != 1 || OPCODE(header) != QUERY)
    return 0; /* must be exactly one query. */
  
  if (!extract_name(header, qlen, &p, name, 1, 4))
    return 0; /* bad packet */
   
  GETSHORT(qtype, p); 
  GETSHORT(qclass, p);

  if (typep)
    *typep = qtype;

  if (qclass == C_IN)
    {
      if (qtype == T_A)
	return F_IPV4;
      if (qtype == T_AAAA)
	return F_IPV6;
      if (qtype == T_ANY)
	return  F_IPV4 | F_IPV6;
    }

  /* F_DNSSECOK as agument to search_servers() inhibits forwarding
     to servers for domains without a trust anchor. This make the
     behaviour for DS and DNSKEY queries we forward the same
     as for DS and DNSKEY queries we originate. */
  if (qtype == T_DS || qtype == T_DNSKEY)
    return F_DNSSECOK;
  
  return F_QUERY;
}

size_t setup_reply(struct dns_header *header, size_t qlen,
		   union all_addr *addrp, unsigned int flags, unsigned long ttl)
{
  unsigned char *p;
  
  if (!(p = skip_questions(header, qlen)))
    return 0;
  
  /* clear authoritative and truncated flags, set QR flag */
  header->hb3 = (header->hb3 & ~(HB3_AA | HB3_TC )) | HB3_QR;
  /* clear AD flag, set RA flag */
  header->hb4 = (header->hb4 & ~HB4_AD) | HB4_RA;

  header->nscount = htons(0);
  header->arcount = htons(0);
  header->ancount = htons(0); /* no answers unless changed below */
  if (flags == F_NOERR)
    SET_RCODE(header, NOERROR); /* empty domain */
  else if (flags == F_NXDOMAIN)
    SET_RCODE(header, NXDOMAIN);
  else if (flags == F_SERVFAIL)
    {
      union all_addr a;
      a.log.rcode = SERVFAIL;
      log_query(F_CONFIG | F_RCODE, "error", &a, NULL);
      SET_RCODE(header, SERVFAIL);
    }
  else if (flags & ( F_IPV4 | F_IPV6))
    {
      if (flags & F_IPV4)
	{ /* we know the address */
	  SET_RCODE(header, NOERROR);
	  header->ancount = htons(1);
	  header->hb3 |= HB3_AA;
	  add_resource_record(header, NULL, NULL, sizeof(struct dns_header), &p, ttl, NULL, T_A, C_IN, "4", addrp);
	}
      
      if (flags & F_IPV6)
	{
	  SET_RCODE(header, NOERROR);
	  header->ancount = htons(ntohs(header->ancount) + 1);
	  header->hb3 |= HB3_AA;
	  add_resource_record(header, NULL, NULL, sizeof(struct dns_header), &p, ttl, NULL, T_AAAA, C_IN, "6", addrp);
	}
    }
  else /* nowhere to forward to */
    {
      union all_addr a;
      a.log.rcode = REFUSED;
      log_query(F_CONFIG | F_RCODE, "error", &a, NULL);
      SET_RCODE(header, REFUSED);
    }
  
  return p - (unsigned char *)header;
}

/* check if name matches local names ie from /etc/hosts or DHCP or local mx names. */
int check_for_local_domain(char *name, time_t now)
{
  struct mx_srv_record *mx;
  struct txt_record *txt;
  struct interface_name *intr;
  struct ptr_record *ptr;
  struct naptr *naptr;

  for (naptr = daemon->naptr; naptr; naptr = naptr->next)
     if (hostname_issubdomain(name, naptr->name))
      return 1;

   for (mx = daemon->mxnames; mx; mx = mx->next)
    if (hostname_issubdomain(name, mx->name))
      return 1;

  for (txt = daemon->txt; txt; txt = txt->next)
    if (hostname_issubdomain(name, txt->name))
      return 1;

  for (intr = daemon->int_names; intr; intr = intr->next)
    if (hostname_issubdomain(name, intr->name))
      return 1;

  for (ptr = daemon->ptr; ptr; ptr = ptr->next)
    if (hostname_issubdomain(name, ptr->name))
      return 1;

  if (cache_find_non_terminal(name, now))
    return 1;

  return 0;
}

/* Is the packet a reply with the answer address equal to addr?
   If so mung is into an NXDOMAIN reply and also put that information
   in the cache. */
int check_for_bogus_wildcard(struct dns_header *header, size_t qlen, char *name, 
			     struct bogus_addr *baddr, time_t now)
{
  unsigned char *p;
  int i, qtype, qclass, rdlen;
  unsigned long ttl;
  struct bogus_addr *baddrp;

  /* skip over questions */
  if (!(p = skip_questions(header, qlen)))
    return 0; /* bad packet */

  for (i = ntohs(header->ancount); i != 0; i--)
    {
      if (!extract_name(header, qlen, &p, name, 1, 10))
	return 0; /* bad packet */
  
      GETSHORT(qtype, p); 
      GETSHORT(qclass, p);
      GETLONG(ttl, p);
      GETSHORT(rdlen, p);
      
      if (qclass == C_IN && qtype == T_A)
	{
	  if (!CHECK_LEN(header, p, qlen, INADDRSZ))
	    return 0;
	  
	  for (baddrp = baddr; baddrp; baddrp = baddrp->next)
	    if (memcmp(&baddrp->addr, p, INADDRSZ) == 0)
	      {
		/* Found a bogus address. Insert that info here, since there no SOA record
		   to get the ttl from in the normal processing */
		cache_start_insert();
		cache_insert(name, NULL, C_IN, now, ttl, F_IPV4 | F_FORWARD | F_NEG | F_NXDOMAIN);
		cache_end_insert();
		
		return 1;
	      }
	}
      
      if (!ADD_RDLEN(header, p, qlen, rdlen))
	return 0;
    }
  
  return 0;
}

int check_for_ignored_address(struct dns_header *header, size_t qlen, struct bogus_addr *baddr)
{
  unsigned char *p;
  int i, qtype, qclass, rdlen;
  struct bogus_addr *baddrp;

  /* skip over questions */
  if (!(p = skip_questions(header, qlen)))
    return 0; /* bad packet */

  for (i = ntohs(header->ancount); i != 0; i--)
    {
      if (!(p = skip_name(p, header, qlen, 10)))
	return 0; /* bad packet */
      
      GETSHORT(qtype, p); 
      GETSHORT(qclass, p);
      p += 4; /* TTL */
      GETSHORT(rdlen, p);
      
      if (qclass == C_IN && qtype == T_A)
	{
	  if (!CHECK_LEN(header, p, qlen, INADDRSZ))
	    return 0;
	  
	  for (baddrp = baddr; baddrp; baddrp = baddrp->next)
	    if (memcmp(&baddrp->addr, p, INADDRSZ) == 0)
	      return 1;
	}
      
      if (!ADD_RDLEN(header, p, qlen, rdlen))
	return 0;
    }
  
  return 0;
}


int add_resource_record(struct dns_header *header, char *limit, int *truncp, int nameoffset, unsigned char **pp, 
			unsigned long ttl, int *offset, unsigned short type, unsigned short class, char *format, ...)
{
  va_list ap;
  unsigned char *sav, *p = *pp;
  int j;
  unsigned short usval;
  long lval;
  char *sval;
  
#define CHECK_LIMIT(size) \
  if (limit && p + (size) > (unsigned char*)limit) goto truncated;

  va_start(ap, format);   /* make ap point to 1st unamed argument */
  
  if (truncp && *truncp)
    goto truncated;
  
  if (nameoffset > 0)
    {
      CHECK_LIMIT(2);
      PUTSHORT(nameoffset | 0xc000, p);
    }
  else
    {
      char *name = va_arg(ap, char *);
      if (name && !(p = do_rfc1035_name(p, name, limit)))
	goto truncated;
      
      if (nameoffset < 0)
	{
	  CHECK_LIMIT(2);
	  PUTSHORT(-nameoffset | 0xc000, p);
	}
      else
	{
	  CHECK_LIMIT(1);
	  *p++ = 0;
	}
    }

  /* type (2) + class (2) + ttl (4) + rdlen (2) */
  CHECK_LIMIT(10);
  
  PUTSHORT(type, p);
  PUTSHORT(class, p);
  PUTLONG(ttl, p);      /* TTL */

  sav = p;              /* Save pointer to RDLength field */
  PUTSHORT(0, p);       /* Placeholder RDLength */

  for (; *format; format++)
    switch (*format)
      {
      case '6':
        CHECK_LIMIT(IN6ADDRSZ);
	sval = va_arg(ap, char *); 
	memcpy(p, sval, IN6ADDRSZ);
	p += IN6ADDRSZ;
	break;
	
      case '4':
        CHECK_LIMIT(INADDRSZ);
	sval = va_arg(ap, char *); 
	memcpy(p, sval, INADDRSZ);
	p += INADDRSZ;
	break;
	
      case 'b':
        CHECK_LIMIT(1);
	usval = va_arg(ap, int);
	*p++ = usval;
	break;
	
      case 's':
        CHECK_LIMIT(2);
	usval = va_arg(ap, int);
	PUTSHORT(usval, p);
	break;
	
      case 'l':
        CHECK_LIMIT(4);
	lval = va_arg(ap, long);
	PUTLONG(lval, p);
	break;
	
      case 'd':
        /* get domain-name answer arg and store it in RDATA field */
        if (offset)
          *offset = p - (unsigned char *)header;
        if (!(p = do_rfc1035_name(p, va_arg(ap, char *), limit)))
	  goto truncated;
	CHECK_LIMIT(1);
        *p++ = 0;
	break;
	
      case 't':
	usval = va_arg(ap, int);
        CHECK_LIMIT(usval);
	sval = va_arg(ap, char *);
	if (usval != 0)
	  memcpy(p, sval, usval);
	p += usval;
	break;

      case 'z':
	sval = va_arg(ap, char *);
	usval = sval ? strlen(sval) : 0;
	if (usval > 255)
	  usval = 255;
        CHECK_LIMIT(usval + 1);
	*p++ = (unsigned char)usval;
	memcpy(p, sval, usval);
	p += usval;
	break;
      }

  va_end(ap);	/* clean up variable argument pointer */
  
  /* Now, store real RDLength. sav already checked against limit. */
  j = p - sav - 2;
  PUTSHORT(j, sav);
  
  *pp = p;
  return 1;
  
 truncated:
  va_end(ap);
  if (truncp)
    *truncp = 1;
  return 0;

#undef CHECK_LIMIT
}

static unsigned long crec_ttl(struct crec *crecp, time_t now)
{
  /* Return 0 ttl for DHCP entries, which might change
     before the lease expires, unless configured otherwise. */

  if (crecp->flags & F_DHCP)
    {
      int conf_ttl = daemon->use_dhcp_ttl ? daemon->dhcp_ttl : daemon->local_ttl;
      
      /* Apply ceiling of actual lease length to configured TTL. */
      if (!(crecp->flags & F_IMMORTAL) && (crecp->ttd - now) < conf_ttl)
	return crecp->ttd - now;
      
      return conf_ttl;
    }	  
  
  /* Immortal entries other than DHCP are local, and hold TTL in TTD field. */
  if (crecp->flags & F_IMMORTAL)
    return crecp->ttd;

  /* Return the Max TTL value if it is lower than the actual TTL */
  if (daemon->max_ttl == 0 || ((unsigned)(crecp->ttd - now) < daemon->max_ttl))
    return crecp->ttd - now;
  else
    return daemon->max_ttl;
}

static int cache_validated(const struct crec *crecp)
{
  return (option_bool(OPT_DNSSEC_VALID) && !(crecp->flags & F_DNSSECOK));
}

/* return zero if we can't answer from cache, or packet size if we can */
size_t answer_request(struct dns_header *header, char *limit, size_t qlen,  
		      struct in_addr local_addr, struct in_addr local_netmask, 
		      time_t now, int ad_reqd, int do_bit, int have_pseudoheader) 
{
  char *name = daemon->namebuff;
  unsigned char *p, *ansp;
  unsigned int qtype, qclass;
  union all_addr addr;
  int nameoffset;
  unsigned short flag;
  int q, ans, anscount = 0, addncount = 0;
  int dryrun = 0;
  struct crec *crecp;
  int nxdomain = 0, notimp = 0, auth = 1, trunc = 0, sec_data = 1;
  struct mx_srv_record *rec;
  size_t len;
  int rd_bit = (header->hb3 & HB3_RD);

  /* never answer queries with RD unset, to avoid cache snooping. */
  if (ntohs(header->ancount) != 0 ||
      ntohs(header->nscount) != 0 ||
      ntohs(header->qdcount) == 0 ||
      OPCODE(header) != QUERY )
    return 0;

  /* Don't return AD set if checking disabled. */
  if (header->hb4 & HB4_CD)
    sec_data = 0;
  
  /* If there is an  additional data section then it will be overwritten by
     partial replies, so we have to do a dry run to see if we can answer
     the query. */
  if (ntohs(header->arcount) != 0)
    dryrun = 1;

  for (rec = daemon->mxnames; rec; rec = rec->next)
    rec->offset = 0;
  
 rerun:
  /* determine end of question section (we put answers there) */
  if (!(ansp = skip_questions(header, qlen)))
    return 0; /* bad packet */
   
  /* now process each question, answers go in RRs after the question */
  p = (unsigned char *)(header+1);

  for (q = ntohs(header->qdcount); q != 0; q--)
    {
      int count = 255; /* catch loops */
      
      /* save pointer to name for copying into answers */
      nameoffset = p - (unsigned char *)header;

      /* now extract name as .-concatenated string into name */
      if (!extract_name(header, qlen, &p, name, 1, 4))
	return 0; /* bad packet */
            
      GETSHORT(qtype, p); 
      GETSHORT(qclass, p);

      ans = 0; /* have we answered this question */

      while (--count != 0 && (crecp = cache_find_by_name(NULL, name, now, F_CNAME)))
	{
	  char *cname_target = cache_get_cname_target(crecp);

	  /* If the client asked for DNSSEC  don't use cached data. */
	  if ((crecp->flags & (F_HOSTS | F_DHCP | F_CONFIG)) ||
	      (rd_bit && (!do_bit || cache_validated(crecp))))
	    {
	      if (crecp->flags & F_CONFIG || qtype == T_CNAME)
		ans = 1;

	      if (!(crecp->flags & F_DNSSECOK))
		sec_data = 0;

	      if (!dryrun)
		{
		  log_query(crecp->flags, name, NULL, record_source(crecp->uid));
		  if (add_resource_record(header, limit, &trunc, nameoffset, &ansp, 
					  crec_ttl(crecp, now), &nameoffset,
					  T_CNAME, C_IN, "d", cname_target))
		    anscount++;
		}

	    }
	  else
	    return 0; /* give up if any cached CNAME in chain can't be used for DNSSEC reasons. */

	  strcpy(name, cname_target);
	}
	  
      if (qtype == T_TXT || qtype == T_ANY)
	{
	  struct txt_record *t;
	  for(t = daemon->txt; t ; t = t->next)
	    {
	      if (t->class == qclass && hostname_isequal(name, t->name))
		{
		  ans = 1, sec_data = 0;
		  if (!dryrun)
		    {
		      unsigned long ttl = daemon->local_ttl;
		      int ok = 1;
#ifndef NO_ID
		      /* Dynamically generate stat record */
		      if (t->stat != 0)
			{
			  ttl = 0;
			  if (!cache_make_stat(t))
			    ok = 0;
			}
#endif
		      if (ok)
			{
			  log_query(F_CONFIG | F_RRNAME, name, NULL, "<TXT>");
			  if (add_resource_record(header, limit, &trunc, nameoffset, &ansp, 
						  ttl, NULL,
						  T_TXT, t->class, "t", t->len, t->txt))
			    anscount++;
			}
		    }
		}
	    }
	}

      if (qclass == C_CHAOS)
	{
	  /* don't forward *.bind and *.server chaos queries - always reply with NOTIMP */
	  if (hostname_issubdomain("bind", name) || hostname_issubdomain("server", name))
	    {
	      if (!ans)
		{
		  notimp = 1, auth = 0;
		  if (!dryrun)
		    {
		       addr.log.rcode = NOTIMP;
		       log_query(F_CONFIG | F_RCODE, name, &addr, NULL);
		    }
		  ans = 1, sec_data = 0;
		}
	    }
	}

      if (qclass == C_IN)
	{
	  struct txt_record *t;

	  for (t = daemon->rr; t; t = t->next)
	    if ((t->class == qtype || qtype == T_ANY) && hostname_isequal(name, t->name))
	      {
		ans = 1;
		sec_data = 0;
		if (!dryrun)
		  {
		    log_query(F_CONFIG | F_RRNAME, name, NULL, querystr(NULL, t->class));
		    if (add_resource_record(header, limit, &trunc, nameoffset, &ansp, 
					    daemon->local_ttl, NULL,
					    t->class, C_IN, "t", t->len, t->txt))
		      anscount++;
		  }
	      }
		
	  if (qtype == T_PTR || qtype == T_ANY)
	    {
	      /* see if it's w.z.y.z.in-addr.arpa format */
	      int is_arpa = in_arpa_name_2_addr(name, &addr);
	      struct ptr_record *ptr;
	      struct interface_name* intr = NULL;

	      for (ptr = daemon->ptr; ptr; ptr = ptr->next)
		if (hostname_isequal(name, ptr->name))
		  break;

	      if (is_arpa == F_IPV4)
		for (intr = daemon->int_names; intr; intr = intr->next)
		  {
		    struct addrlist *addrlist;
		    
		    for (addrlist = intr->addr; addrlist; addrlist = addrlist->next)
		      if (!(addrlist->flags & ADDRLIST_IPV6) && addr.addr4.s_addr == addrlist->addr.addr4.s_addr)
			break;
		    
		    if (addrlist)
		      break;
		    else
		      while (intr->next && strcmp(intr->intr, intr->next->intr) == 0)
			intr = intr->next;
		  }
	      else if (is_arpa == F_IPV6)
		for (intr = daemon->int_names; intr; intr = intr->next)
		  {
		    struct addrlist *addrlist;
		    
		    for (addrlist = intr->addr; addrlist; addrlist = addrlist->next)
		      if ((addrlist->flags & ADDRLIST_IPV6) && IN6_ARE_ADDR_EQUAL(&addr.addr6, &addrlist->addr.addr6))
			break;
		    
		    if (addrlist)
		      break;
		    else
		      while (intr->next && strcmp(intr->intr, intr->next->intr) == 0)
			intr = intr->next;
		  }
	      
	      if (intr)
		{
		  sec_data = 0;
		  ans = 1;
		  if (!dryrun)
		    {
		      log_query(is_arpa | F_REVERSE | F_CONFIG, intr->name, &addr, NULL);
		      if (add_resource_record(header, limit, &trunc, nameoffset, &ansp, 
					      daemon->local_ttl, NULL,
					      T_PTR, C_IN, "d", intr->name))
			anscount++;
		    }
		}
	      else if (ptr)
		{
		  ans = 1;
		  sec_data = 0;
		  if (!dryrun)
		    {
		      log_query(F_CONFIG | F_RRNAME, name, NULL, "<PTR>");
		      for (ptr = daemon->ptr; ptr; ptr = ptr->next)
			if (hostname_isequal(name, ptr->name) &&
			    add_resource_record(header, limit, &trunc, nameoffset, &ansp, 
						daemon->local_ttl, NULL,
						T_PTR, C_IN, "d", ptr->ptr))
			  anscount++;
			 
		    }
		}
	      else if ((crecp = cache_find_by_addr(NULL, &addr, now, is_arpa)))
		{
		  /* Don't use cache when DNSSEC data required, unless we know that
		     the zone is unsigned, which implies that we're doing
		     validation. */
		  if ((crecp->flags & (F_HOSTS | F_DHCP | F_CONFIG)) ||
		      (rd_bit && (!do_bit || cache_validated(crecp)) ))
		    {
		      do 
			{ 
			  /* don't answer wildcard queries with data not from /etc/hosts or dhcp leases */
			  if (qtype == T_ANY && !(crecp->flags & (F_HOSTS | F_DHCP)))
			    continue;
			  
			  if (!(crecp->flags & F_DNSSECOK))
			    sec_data = 0;
			   
			  ans = 1;
			   
			  if (crecp->flags & F_NEG)
			    {
			      auth = 0;
			      if (crecp->flags & F_NXDOMAIN)
				nxdomain = 1;
			      if (!dryrun)
				log_query(crecp->flags & ~F_FORWARD, name, &addr, NULL);
			    }
			  else
			    {
			      if (!(crecp->flags & (F_HOSTS | F_DHCP)))
				auth = 0;
			      if (!dryrun)
				{
				  log_query(crecp->flags & ~F_FORWARD, cache_get_name(crecp), &addr, 
					    record_source(crecp->uid));
				  
				  if (add_resource_record(header, limit, &trunc, nameoffset, &ansp, 
							  crec_ttl(crecp, now), NULL,
							  T_PTR, C_IN, "d", cache_get_name(crecp)))
				    anscount++;
				}
			    }
			} while ((crecp = cache_find_by_addr(crecp, &addr, now, is_arpa)));
		    }
		}
	      else if (is_rev_synth(is_arpa, &addr, name))
		{
		  ans = 1;
		  sec_data = 0;
		  if (!dryrun)
		    {
		      log_query(F_CONFIG | F_REVERSE | is_arpa, name, &addr, NULL); 
		      
		      if (add_resource_record(header, limit, &trunc, nameoffset, &ansp, 
					      daemon->local_ttl, NULL,
					      T_PTR, C_IN, "d", name))
			      anscount++;
		    }
		}
	      else if (option_bool(OPT_BOGUSPRIV) && (
		       (is_arpa == F_IPV6 && private_net6(&addr.addr6)) ||
		       (is_arpa == F_IPV4 && private_net(addr.addr4, 1))))
		{
		  struct server *serv;
		  unsigned int namelen = strlen(name);
		  char *nameend = name + namelen;

		  /* see if have rev-server set */
		  for (serv = daemon->servers; serv; serv = serv->next)
		    {
		      unsigned int domainlen;
		      char *matchstart;

		      if ((serv->flags & (SERV_HAS_DOMAIN | SERV_NO_ADDR)) != SERV_HAS_DOMAIN)
		        continue;

		      domainlen = strlen(serv->domain);
		      if (domainlen == 0 || domainlen > namelen)
		        continue;

		      matchstart = nameend - domainlen;
		      if (hostname_isequal(matchstart, serv->domain) &&
		          (namelen == domainlen || *(matchstart-1) == '.' ))
			break;
		    }

		  /* if no configured server, not in cache, enabled and private IPV4 address, return NXDOMAIN */
		  if (!serv)
		    {
		      ans = 1;
		      sec_data = 0;
		      nxdomain = 1;
		      if (!dryrun)
			log_query(F_CONFIG | F_REVERSE | is_arpa | F_NEG | F_NXDOMAIN,
				  name, &addr, NULL);
		    }
		}
	    }

	  for (flag = F_IPV4; flag; flag = (flag == F_IPV4) ? F_IPV6 : 0)
	    {
	      unsigned short type = (flag == F_IPV6) ? T_AAAA : T_A;
	      struct interface_name *intr;

	      if (qtype != type && qtype != T_ANY)
		continue;
	      
	      /* interface name stuff */
	      for (intr = daemon->int_names; intr; intr = intr->next)
		if (hostname_isequal(name, intr->name))
		  break;
	      
	      if (intr)
		{
		  struct addrlist *addrlist;
		  int gotit = 0, localise = 0;

		  enumerate_interfaces(0);
		    
		  /* See if a putative address is on the network from which we received
		     the query, is so we'll filter other answers. */
		  if (local_addr.s_addr != 0 && option_bool(OPT_LOCALISE) && type == T_A)
		    for (intr = daemon->int_names; intr; intr = intr->next)
		      if (hostname_isequal(name, intr->name))
			for (addrlist = intr->addr; addrlist; addrlist = addrlist->next)
			  if (!(addrlist->flags & ADDRLIST_IPV6) && 
			      is_same_net(addrlist->addr.addr4, local_addr, local_netmask))
			    {
			      localise = 1;
			      break;
			    }
		  
		  for (intr = daemon->int_names; intr; intr = intr->next)
		    if (hostname_isequal(name, intr->name))
		      {
			for (addrlist = intr->addr; addrlist; addrlist = addrlist->next)
			  if (((addrlist->flags & ADDRLIST_IPV6) ? T_AAAA : T_A) == type)
			    {
			      if (localise && 
				  !is_same_net(addrlist->addr.addr4, local_addr, local_netmask))
				continue;

			      if (addrlist->flags & ADDRLIST_REVONLY)
				continue;

			      ans = 1;	
			      sec_data = 0;
			      if (!dryrun)
				{
				  gotit = 1;
				  log_query(F_FORWARD | F_CONFIG | flag, name, &addrlist->addr, NULL);
				  if (add_resource_record(header, limit, &trunc, nameoffset, &ansp, 
							  daemon->local_ttl, NULL, type, C_IN, 
							  type == T_A ? "4" : "6", &addrlist->addr))
				    anscount++;
				}
			    }
		      }
		  
		  if (!dryrun && !gotit)
		    log_query(F_FORWARD | F_CONFIG | flag | F_NEG, name, NULL, NULL);
		     
		  continue;
		}

	      if ((crecp = cache_find_by_name(NULL, name, now, flag | (dryrun ? F_NO_RR : 0))))
		{
		  int localise = 0;
		  
		  /* See if a putative address is on the network from which we received
		     the query, is so we'll filter other answers. */
		  if (local_addr.s_addr != 0 && option_bool(OPT_LOCALISE) && flag == F_IPV4)
		    {
		      struct crec *save = crecp;
		      do {
			if ((crecp->flags & F_HOSTS) &&
			    is_same_net(crecp->addr.addr4, local_addr, local_netmask))
			  {
			    localise = 1;
			    break;
			  } 
			} while ((crecp = cache_find_by_name(crecp, name, now, flag)));
		      crecp = save;
		    }

		  /* If the client asked for DNSSEC  don't use cached data. */
		  if ((crecp->flags & (F_HOSTS | F_DHCP | F_CONFIG)) ||
		      (rd_bit && (!do_bit || cache_validated(crecp)) ))
		    do
		      { 
			/* don't answer wildcard queries with data not from /etc/hosts
			   or DHCP leases */
			if (qtype == T_ANY && !(crecp->flags & (F_HOSTS | F_DHCP | F_CONFIG)))
			  break;
			
			if (!(crecp->flags & F_DNSSECOK))
			  sec_data = 0;
			
			if (crecp->flags & F_NEG)
			  {
			    ans = 1;
			    auth = 0;
			    if (crecp->flags & F_NXDOMAIN)
			      nxdomain = 1;
			    if (!dryrun)
			      log_query(crecp->flags, name, NULL, NULL);
			  }
			else 
			  {
			    /* If we are returning local answers depending on network,
			       filter here. */
			    if (localise && 
				(crecp->flags & F_HOSTS) &&
				!is_same_net(crecp->addr.addr4, local_addr, local_netmask))
			      continue;
			    
			    if (!(crecp->flags & (F_HOSTS | F_DHCP)))
			      auth = 0;
			    
			    ans = 1;
			    if (!dryrun)
			      {
				log_query(crecp->flags & ~F_REVERSE, name, &crecp->addr,
					  record_source(crecp->uid));
				
				if (add_resource_record(header, limit, &trunc, nameoffset, &ansp, 
							crec_ttl(crecp, now), NULL, type, C_IN, 
							type == T_A ? "4" : "6", &crecp->addr))
				  anscount++;
			      }
			  }
		      } while ((crecp = cache_find_by_name(crecp, name, now, flag)));
		}
	      else if (is_name_synthetic(flag, name, &addr))
		{
		  ans = 1, sec_data = 0;
		  if (!dryrun)
		    {
		      log_query(F_FORWARD | F_CONFIG | flag, name, &addr, NULL);
		      if (add_resource_record(header, limit, &trunc, nameoffset, &ansp, 
					      daemon->local_ttl, NULL, type, C_IN, type == T_A ? "4" : "6", &addr))
			anscount++;
		    }
		}
	    }

	  if (qtype == T_MX || qtype == T_ANY)
	    {
	      int found = 0;
	      for (rec = daemon->mxnames; rec; rec = rec->next)
		if (!rec->issrv && hostname_isequal(name, rec->name))
		  {
		    ans = found = 1;
		    sec_data = 0;
		    if (!dryrun)
		      {
			int offset;
			log_query(F_CONFIG | F_RRNAME, name, NULL, "<MX>");
			if (add_resource_record(header, limit, &trunc, nameoffset, &ansp, daemon->local_ttl,
						&offset, T_MX, C_IN, "sd", rec->weight, rec->target))
			  {
			    anscount++;
			    if (rec->target)
			      rec->offset = offset;
			  }
		      }
		  }
	      
	      if (!found && (option_bool(OPT_SELFMX) || option_bool(OPT_LOCALMX)) &&
		  cache_find_by_name(NULL, name, now, F_HOSTS | F_DHCP | F_NO_RR))
		{ 
		  ans = 1;
		  sec_data = 0;
		  if (!dryrun)
		    {
		      log_query(F_CONFIG | F_RRNAME, name, NULL, "<MX>");
		      if (add_resource_record(header, limit, &trunc, nameoffset, &ansp, daemon->local_ttl, NULL, 
					      T_MX, C_IN, "sd", 1, 
					      option_bool(OPT_SELFMX) ? name : daemon->mxtarget))
			anscount++;
		    }
		}
	    }
	  	  
	  if (qtype == T_SRV || qtype == T_ANY)
	    {
	      int found = 0;
	      struct mx_srv_record *move = NULL, **up = &daemon->mxnames;

	      for (rec = daemon->mxnames; rec; rec = rec->next)
		if (rec->issrv && hostname_isequal(name, rec->name))
		  {
		    found = ans = 1;
		    sec_data = 0;
		    if (!dryrun)
		      {
			int offset;
			log_query(F_CONFIG | F_RRNAME, name, NULL, "<SRV>");
			if (add_resource_record(header, limit, &trunc, nameoffset, &ansp, daemon->local_ttl, 
						&offset, T_SRV, C_IN, "sssd", 
						rec->priority, rec->weight, rec->srvport, rec->target))
			  {
			    anscount++;
			    if (rec->target)
			      rec->offset = offset;
			  }
		      }
		    
		    /* unlink first SRV record found */
		    if (!move)
		      {
			move = rec;
			*up = rec->next;
		      }
		    else
		      up = &rec->next;      
		  }
		else
		  up = &rec->next;

	      /* put first SRV record back at the end. */
	      if (move)
		{
		  *up = move;
		  move->next = NULL;
		}

	      if (!found)
		{
		  if ((crecp = cache_find_by_name(NULL, name, now, F_SRV | (dryrun ? F_NO_RR : 0))) &&
		      rd_bit && (!do_bit || (option_bool(OPT_DNSSEC_VALID) && !(crecp->flags & F_DNSSECOK))))
		    {
		      if (!(crecp->flags & F_DNSSECOK))
			sec_data = 0;
		      
		      auth = 0;
		      found = ans = 1;
		      
		      do {
			if (crecp->flags & F_NEG)
			  {
			    if (crecp->flags & F_NXDOMAIN)
			      nxdomain = 1;
			    if (!dryrun)
			      log_query(crecp->flags, name, NULL, NULL);
			  }
			else if (!dryrun)
			  {
			    char *target = blockdata_retrieve(crecp->addr.srv.target, crecp->addr.srv.targetlen, NULL);
			    log_query(crecp->flags, name, NULL, 0);
			    
			    if (add_resource_record(header, limit, &trunc, nameoffset, &ansp, 
						    crec_ttl(crecp, now), NULL, T_SRV, C_IN, "sssd",
						    crecp->addr.srv.priority, crecp->addr.srv.weight, crecp->addr.srv.srvport,
						    target))
			      anscount++;
			  }
		      } while ((crecp = cache_find_by_name(crecp, name, now, F_SRV)));
		    }
		}

	      if (!found && option_bool(OPT_FILTER) && (qtype == T_SRV || (qtype == T_ANY && strchr(name, '_'))))
		{
		  ans = 1;
		  sec_data = 0;
		  if (!dryrun)
		    log_query(F_CONFIG | F_NEG, name, NULL, NULL);
		}
	    }

	  if (qtype == T_NAPTR || qtype == T_ANY)
	    {
	      struct naptr *na;
	      for (na = daemon->naptr; na; na = na->next)
		if (hostname_isequal(name, na->name))
		  {
		    ans = 1;
		    sec_data = 0;
		    if (!dryrun)
		      {
			log_query(F_CONFIG | F_RRNAME, name, NULL, "<NAPTR>");
			if (add_resource_record(header, limit, &trunc, nameoffset, &ansp, daemon->local_ttl, 
						NULL, T_NAPTR, C_IN, "sszzzd", 
						na->order, na->pref, na->flags, na->services, na->regexp, na->replace))
			  anscount++;
		      }
		  }
	    }
	  
	  if (qtype == T_MAILB)
	    ans = 1, nxdomain = 1, sec_data = 0;

	  if (qtype == T_SOA && option_bool(OPT_FILTER))
	    {
	      ans = 1;
	      sec_data = 0;
	      if (!dryrun)
		log_query(F_CONFIG | F_NEG, name, &addr, NULL);
	    }
	}

      if (!ans)
	return 0; /* failed to answer a question */
    }
  
  if (dryrun)
    {
      dryrun = 0;
      goto rerun;
    }
  
  /* create an additional data section, for stuff in SRV and MX record replies. */
  for (rec = daemon->mxnames; rec; rec = rec->next)
    if (rec->offset != 0)
      {
	/* squash dupes */
	struct mx_srv_record *tmp;
	for (tmp = rec->next; tmp; tmp = tmp->next)
	  if (tmp->offset != 0 && hostname_isequal(rec->target, tmp->target))
	    tmp->offset = 0;
	
	crecp = NULL;
	while ((crecp = cache_find_by_name(crecp, rec->target, now, F_IPV4 | F_IPV6)))
	  {
	    int type =  crecp->flags & F_IPV4 ? T_A : T_AAAA;

	    if (crecp->flags & F_NEG)
	      continue;

	    if (add_resource_record(header, limit, NULL, rec->offset, &ansp, 
				    crec_ttl(crecp, now), NULL, type, C_IN, 
				    crecp->flags & F_IPV4 ? "4" : "6", &crecp->addr))
	      addncount++;
	  }
      }
  
  /* done all questions, set up header and return length of result */
  /* clear authoritative and truncated flags, set QR flag */
  header->hb3 = (header->hb3 & ~(HB3_AA | HB3_TC)) | HB3_QR;
  /* set RA flag */
  header->hb4 |= HB4_RA;
   
  /* authoritative - only hosts and DHCP derived names. */
  if (auth)
    header->hb3 |= HB3_AA;
  
  /* truncation */
  if (trunc)
    header->hb3 |= HB3_TC;
  
  if (nxdomain)
    SET_RCODE(header, NXDOMAIN);
  else if (notimp)
    SET_RCODE(header, NOTIMP);
  else
    SET_RCODE(header, NOERROR); /* no error */
  header->ancount = htons(anscount);
  header->nscount = htons(0);
  header->arcount = htons(addncount);

  len = ansp - (unsigned char *)header;
  
  /* Advertise our packet size limit in our reply */
  if (have_pseudoheader)
    len = add_pseudoheader(header, len, (unsigned char *)limit, daemon->edns_pktsz, 0, NULL, 0, do_bit, 0);
  
  if (ad_reqd && sec_data)
    header->hb4 |= HB4_AD;
  else
    header->hb4 &= ~HB4_AD;
  
  return len;
}