--- libc/resolv/nss_dns/dns-host.c	2003/10/26 08:33:27	1.38
+++ libc/resolv/nss_dns/dns-host.c	2004/01/15 09:45:57	1.39
@@ -1,4 +1,4 @@
-/* Copyright (C) 1996-2000, 2001, 2002, 2003 Free Software Foundation, Inc.
+/* Copyright (C) 1996-2003, 2004 Free Software Foundation, Inc.
    This file is part of the GNU C Library.
    Extended from original form by Ulrich Drepper <drepper@cygnus.com>, 1996.
 
@@ -298,6 +298,8 @@
       return NSS_STATUS_UNAVAIL;
     }
 
+  host_buffer.buf = orig_host_buffer = (querybuf *) alloca (1024);
+
   switch (af)
     {
     case AF_INET:
@@ -305,29 +307,38 @@
 	       (uaddr[2] & 0xff), (uaddr[1] & 0xff), (uaddr[0] & 0xff));
       break;
     case AF_INET6:
-      /* XXX Maybe we need an option to select whether to use the nibble
-	 or the bitfield form.  The RFC requires the bitfield form so
-	 we use it.  */
+      /* Only lookup with the byte string format if the user wants it.  */
+      if (__builtin_expect (_res.options & RES_USEBSTRING, 0))
+	{
+	  qp = stpcpy (qbuf, "\\[x");
+	  for (n = 0; n < IN6ADDRSZ; ++n)
+	    qp += sprintf (qp, "%02hhx", uaddr[n]);
+	  strcpy (qp, "].ip6.arpa");
+	  n = __libc_res_nquery (&_res, qbuf, C_IN, T_PTR,
+				 host_buffer.buf->buf, 1024, &host_buffer.ptr);
+	  if (n >= 0)
+	    goto got_it_already;
+	}
       qp = qbuf;
-      qp = stpcpy (qbuf, "\\[x");
-      for (n = 0; n < IN6ADDRSZ; ++n)
-	qp += sprintf (qp, "%02hhx", uaddr[n]);
-      strcpy (qp, "].ip6.arpa");
+      for (n = IN6ADDRSZ - 1; n >= 0; n--)
+	{
+	  static const char nibblechar[16] = "0123456789abcdef";
+	  *qp++ = nibblechar[uaddr[n] & 0xf];
+	  *qp++ = '.';
+	  *qp++ = nibblechar[(uaddr[n] >> 4) & 0xf];
+	  *qp++ = '.';
+	}
+      strcpy(qp, "ip6.arpa");
       break;
     default:
       /* Cannot happen.  */
       break;
     }
 
-  host_buffer.buf = orig_host_buffer = (querybuf *) alloca (1024);
-
   n = __libc_res_nquery (&_res, qbuf, C_IN, T_PTR, host_buffer.buf->buf,
 			 1024, &host_buffer.ptr);
   if (n < 0 && af == AF_INET6)
     {
-      qp = qbuf;
-      for (n = IN6ADDRSZ - 1; n >= 0; n--)
-	qp += sprintf (qp, "%x.%x.", uaddr[n] & 0xf, (uaddr[n] >> 4) & 0xf);
       strcpy (qp, "ip6.int");
       n = __libc_res_nquery (&_res, qbuf, C_IN, T_PTR, host_buffer.buf->buf,
 			     host_buffer.buf != orig_host_buffer
@@ -342,6 +353,7 @@
       return errno == ECONNREFUSED ? NSS_STATUS_UNAVAIL : NSS_STATUS_NOTFOUND;
     }
 
+ got_it_already:
   status = getanswer_r (host_buffer.buf, n, qbuf, T_PTR, result, buffer, buflen,
 			errnop, h_errnop, 0 /* XXX */);
   if (host_buffer.buf != orig_host_buffer)
--- libc/resolv/resolv.h	2002/12/15 23:22:50	1.37
+++ libc/resolv/resolv.h	2004/01/15 09:41:58	1.38
@@ -199,6 +199,8 @@
 #define	RES_NOCHECKNAME	0x00008000	/* do not check names for sanity. */
 #define	RES_KEEPTSIG	0x00010000	/* do not strip TSIG records */
 #define	RES_BLAST	0x00020000	/* blast all recursive servers */
+#define RES_USEBSTRING	0x00040000	/* IPv6 reverse lookup with byte
+					   strings */
 
 #define RES_DEFAULT	(RES_RECURSE | RES_DEFNAMES | RES_DNSRCH)
 
--- libc/resolv/res_debug.c	2002/08/08 02:01:31	1.28
+++ libc/resolv/res_debug.c	2004/01/15 09:43:35	1.29
@@ -572,6 +572,10 @@
 	case RES_DNSRCH:	return "dnsrch";
 	case RES_INSECURE1:	return "insecure1";
 	case RES_INSECURE2:	return "insecure2";
+	case RES_USE_INET6:	return "inet6";
+	case RES_ROTATE:	return "rotate";
+	case RES_NOCHECKNAME:	return "no-check-names";
+	case RES_USEBSTRING:	return "ip6-bytstring";
 				/* XXX nonreentrant */
 	default:		sprintf(nbuf, "?0x%lx?", (u_long)option);
 				return (nbuf);
--- libc/resolv/res_init.c	2003/09/04 12:48:52	1.34
+++ libc/resolv/res_init.c	2004/01/15 09:44:18	1.35
@@ -489,6 +489,9 @@
 #endif
 		} else if (!strncmp(cp, "inet6", sizeof("inet6") - 1)) {
 			statp->options |= RES_USE_INET6;
+		} else if (!strncmp(cp, "ip6-bytestring",
+				    sizeof("ip6-bytestring") - 1)) {
+			statp->options |= RES_USEBSTRING;
 		} else if (!strncmp(cp, "rotate", sizeof("rotate") - 1)) {
 			statp->options |= RES_ROTATE;
 		} else if (!strncmp(cp, "no-check-names",