From: Ulrich Drepper <drepper@redhat.com>
Date: Sat, 18 Sep 2004 18:00:50 +0000 (+0000)
Subject: (res_nmkquery): Randomize request ID every time.
X-Git-Tag: upstream/2.30~17499
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=e33b89df220fae37a1819b3fa39d1cc3cd2e31aa;p=external%2Fglibc.git

(res_nmkquery): Randomize request ID every time.
---

diff --git a/resolv/res_mkquery.c b/resolv/res_mkquery.c
index 05b94bd..2d25b16 100644
--- a/resolv/res_mkquery.c
+++ b/resolv/res_mkquery.c
@@ -1,7 +1,7 @@
 /*
  * Copyright (c) 1985, 1993
  *    The Regents of the University of California.  All rights reserved.
- * 
+ *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
@@ -13,7 +13,7 @@
  * 4. Neither the name of the University nor the names of its contributors
  *    may be used to endorse or promote products derived from this software
  *    without specific prior written permission.
- * 
+ *
  * THIS SOFTWARE IS PROVIDED BY THE REGENTS 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
@@ -29,14 +29,14 @@
 
 /*
  * Portions Copyright (c) 1993 by Digital Equipment Corporation.
- * 
+ *
  * Permission to use, copy, modify, and distribute this software for any
  * purpose with or without fee is hereby granted, provided that the above
  * copyright notice and this permission notice appear in all copies, and that
  * the name of Digital Equipment Corporation not be used in advertising or
  * publicity pertaining to distribution of the document or software without
  * specific, written prior permission.
- * 
+ *
  * THE SOFTWARE IS PROVIDED "AS IS" AND DIGITAL EQUIPMENT CORP. DISCLAIMS ALL
  * WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES
  * OF MERCHANTABILITY AND FITNESS.   IN NO EVENT SHALL DIGITAL EQUIPMENT
@@ -81,6 +81,13 @@ static const char rcsid[] = "$BINDId: res_mkquery.c,v 8.12 1999/10/13 16:39:40 v
 /* Options.  Leave them on. */
 /* #define DEBUG */
 
+#ifdef _LIBC
+# include <hp-timing.h>
+# if HP_TIMING_AVAIL
+#  define RANDOM_BITS(Var) { uint64_t v64; HP_TIMING_NOW (v64); Var = v64; }
+# endif
+#endif
+
 extern const char *_res_opcodes[];
 
 /*
@@ -115,7 +122,28 @@ res_nmkquery(res_state statp,
 		return (-1);
 	memset(buf, 0, HFIXEDSZ);
 	hp = (HEADER *) buf;
+	/* We randomize the IDs every time.  The old code just
+	   incremented by one after the initial randomization which
+	   still predictable if the application does multiple
+	   requests.  */
+#if 0
 	hp->id = htons(++statp->id);
+#else
+	hp->id = htons(statp->id);
+	int randombits;
+	do
+	  {
+#ifdef RANDOM_BITS
+	    RANDOM_BITS (randombits);
+#else
+	    struct timeval tv;
+	    __gettimeofday (&tv, NULL);
+	    random_time_bits = (tv.tv_sec << 8) ^ tv.tv_usec;
+#endif
+	  }
+	while (randombits == 0);
+	statp->id = (statp->id + randombits) & 0xffff;
+#endif
 	hp->opcode = op;
 	hp->rd = (statp->options & RES_RECURSE) != 0;
 	hp->rcode = NOERROR;