From 0864b4939d63d98b25901f9db1d42f52e0c85a62 Mon Sep 17 00:00:00 2001
From: itojun <itojun@NetBSD.org>
Date: Tue, 25 Nov 2003 18:13:55 +0000
Subject: [PATCH] "seed2" was ruining non-repeating property, so remove it. 
 discussed on tech-net

---
 sys/netinet/ip_id.c   | 9 ++++-----
 sys/netinet6/ip6_id.c | 9 ++++-----
 2 files changed, 8 insertions(+), 10 deletions(-)

diff --git a/sys/netinet/ip_id.c b/sys/netinet/ip_id.c
index c48d18134b67..f42a46ab9d29 100644
--- a/sys/netinet/ip_id.c
+++ b/sys/netinet/ip_id.c
@@ -1,4 +1,4 @@
-/*	$NetBSD: ip_id.c,v 1.3 2003/11/19 18:39:34 jonathan Exp $	*/
+/*	$NetBSD: ip_id.c,v 1.4 2003/11/25 18:13:55 itojun Exp $	*/
 /*	$OpenBSD: ip_id.c,v 1.6 2002/03/15 18:19:52 millert Exp $	*/
 
 /*
@@ -57,7 +57,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: ip_id.c,v 1.3 2003/11/19 18:39:34 jonathan Exp $");
+__KERNEL_RCSID(0, "$NetBSD: ip_id.c,v 1.4 2003/11/25 18:13:55 itojun Exp $");
 
 #include "opt_inet.h"
 
@@ -85,7 +85,7 @@ const static u_int16_t pfacts[PFAC_N] = {
 };
 
 static u_int16_t ru_x;
-static u_int16_t ru_seed, ru_seed2;
+static u_int16_t ru_seed;
 static u_int16_t ru_a, ru_b;
 static u_int16_t ru_g;
 static u_int16_t ru_counter = 0;
@@ -137,7 +137,6 @@ ip_initid(void)
 
 	/* 15 bits of random seed */
 	ru_seed = (tmp >> 16) & 0x7FFF;
-	ru_seed2 = arc4random() & 0x7FFF;
 
 	/* Determine the LCG we use */
 	ru_b = ((tmp = arc4random()) & 0xfffe) | 1;
@@ -194,5 +193,5 @@ ip_randomid(void)
 
 	ru_counter += i;
 
-	return (ru_seed ^ pmod(ru_g, ru_seed2 ^ ru_x,RU_N)) | ru_msb;
+	return (ru_seed ^ pmod(ru_g, ru_x, RU_N)) | ru_msb;
 }
diff --git a/sys/netinet6/ip6_id.c b/sys/netinet6/ip6_id.c
index 10f2d4db5c07..7b090c3f0d4f 100644
--- a/sys/netinet6/ip6_id.c
+++ b/sys/netinet6/ip6_id.c
@@ -1,4 +1,4 @@
-/*	$NetBSD: ip6_id.c,v 1.9 2003/09/16 00:31:23 itojun Exp $	*/
+/*	$NetBSD: ip6_id.c,v 1.10 2003/11/25 18:13:55 itojun Exp $	*/
 /*	$KAME: ip6_id.c,v 1.8 2003/09/06 13:41:06 itojun Exp $	*/
 /*	$OpenBSD: ip_id.c,v 1.6 2002/03/15 18:19:52 millert Exp $	*/
 
@@ -87,7 +87,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: ip6_id.c,v 1.9 2003/09/16 00:31:23 itojun Exp $");
+__KERNEL_RCSID(0, "$NetBSD: ip6_id.c,v 1.10 2003/11/25 18:13:55 itojun Exp $");
 
 #include <sys/types.h>
 #include <sys/param.h>
@@ -113,7 +113,7 @@ struct randomtab {
 	u_int32_t ru_msb;
 
 	u_int32_t ru_x;
-	u_int32_t ru_seed, ru_seed2;
+	u_int32_t ru_seed;
 	u_int32_t ru_a, ru_b;
 	u_int32_t ru_g;
 	long ru_reseed;
@@ -186,7 +186,6 @@ initid(struct randomtab *p)
 
 	/* (bits - 1) bits of random seed */
 	p->ru_seed = arc4random() & (~0U >> (32 - p->ru_bits + 1));
-	p->ru_seed2 = arc4random() & (~0U >> (32 - p->ru_bits + 1));
 
 	/* Determine the LCG we use */
 	p->ru_b = (arc4random() & (~0U >> (32 - p->ru_bits))) | 1;
@@ -243,7 +242,7 @@ randomid(struct randomtab *p)
 
 	p->ru_counter += i;
 
-	return (p->ru_seed ^ pmod(p->ru_g, p->ru_seed2 ^ p->ru_x, p->ru_n)) |
+	return (p->ru_seed ^ pmod(p->ru_g, p->ru_x, p->ru_n)) |
 	    p->ru_msb;
 }