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[src/trunk]: src/sys/netinet6 netinet6: Mark randomid unused.



details:   https://anonhg.NetBSD.org/src/rev/092d4da097ef
branches:  trunk
changeset: 981305:092d4da097ef
user:      christos <christos%NetBSD.org@localhost>
date:      Sun Mar 07 14:59:36 2021 +0000

description:
netinet6: Mark randomid unused.

Will make merging and bisection easier if anything goes wrong with
flow label or fragment id randomization changes.

(from riastradh)

diffstat:

 sys/netinet6/ip6_id.c |  245 ++++---------------------------------------------
 1 files changed, 20 insertions(+), 225 deletions(-)

diffs (275 lines):

diff -r 05c45c7e2c7c -r 092d4da097ef sys/netinet6/ip6_id.c
--- a/sys/netinet6/ip6_id.c     Sun Mar 07 14:58:54 2021 +0000
+++ b/sys/netinet6/ip6_id.c     Sun Mar 07 14:59:36 2021 +0000
@@ -1,9 +1,7 @@
-/*     $NetBSD: ip6_id.c,v 1.19 2019/10/18 04:09:02 msaitoh 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 $       */
+/*     $NetBSD: ip6_id.c,v 1.20 2021/03/07 14:59:36 christos Exp $     */
 
-/*
- * Copyright (C) 2003 WIDE Project.
+/*-
+ * Copyright (c) 2020 The NetBSD Foundation, Inc.
  * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
@@ -14,241 +12,38 @@
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
  *    documentation and/or other materials provided with the distribution.
- * 3. Neither the name of the project 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 PROJECT 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
- * ARE DISCLAIMED.  IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
- * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
- * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
- * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
- * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
- * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
- * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
- * SUCH DAMAGE.
- */
-
-/*
- * Copyright 1998 Niels Provos <provos%citi.umich.edu@localhost>
- * All rights reserved.
- *
- * Theo de Raadt <deraadt%openbsd.org@localhost> came up with the idea of using
- * such a mathematical system to generate more random (yet non-repeating)
- * ids to solve the resolver/named problem.  But Niels designed the
- * actual system based on the constraints.
- *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions
- * are met:
- * 1. Redistributions of source code must retain the above copyright
- *    notice, this list of conditions and the following disclaimer.
- * 2. Redistributions in binary form must reproduce the above copyright
- *    notice, this list of conditions and the following disclaimer in the
- *    documentation and/or other materials provided with the distribution.
  *
- * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
- * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
- * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
- * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
- * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
- * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
- * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
- */
-
-/*
- * seed = random (bits - 1) bit
- * n = prime, g0 = generator to n,
- * j = random so that gcd(j,n-1) == 1
- * g = g0^j mod n will be a generator again.
- *
- * X[0] = random seed.
- * X[n] = a*X[n-1]+b mod m is a Linear Congruential Generator
- * with a = 7^(even random) mod m,
- *      b = random with gcd(b,m) == 1
- *      m = constant and a maximal period of m-1.
- *
- * The transaction id is determined by:
- * id[n] = seed xor (g^X[n] mod n)
- *
- * Effectively the id is restricted to the lower (bits - 1) bits, thus
- * yielding two different cycles by toggling the msb on and off.
- * This avoids reuse issues caused by reseeding.
+ * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. 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 ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
+ * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: ip6_id.c,v 1.19 2019/10/18 04:09:02 msaitoh Exp $");
+__KERNEL_RCSID(0, "$NetBSD: ip6_id.c,v 1.20 2021/03/07 14:59:36 christos Exp $");
 
-#include <sys/param.h>
+#include <sys/types.h>
 #include <sys/cprng.h>
 
-#include <lib/libkern/libkern.h>
-
-#include <net/if.h>
-#include <netinet/in.h>
-#include <netinet/ip6.h>
 #include <netinet6/ip6_var.h>
 
-struct randomtab {
-       const int       ru_bits; /* resulting bits */
-       const long      ru_out; /* Time after wich will be reseeded */
-       const u_int32_t ru_max; /* Uniq cycle, avoid blackjack prediction */
-       const u_int32_t ru_gen; /* Starting generator */
-       const u_int32_t ru_n;   /* ru_n: prime, ru_n - 1: product of pfacts[] */
-       const u_int32_t ru_agen; /* determine ru_a as ru_agen^(2*rand) */
-       const u_int32_t ru_m;   /* ru_m = 2^x*3^y */
-       const u_int32_t ru_pfacts[4];   /* factors of ru_n */
-
-       u_int32_t ru_counter;
-       u_int32_t ru_msb;
-
-       u_int32_t ru_x;
-       u_int32_t ru_seed, ru_seed2;
-       u_int32_t ru_a, ru_b;
-       u_int32_t ru_g;
-       long ru_reseed;
-};
-
-static struct randomtab randomtab_32 = {
-       .ru_bits = 32,          /* resulting bits */
-       .ru_out = 180,          /* Time after wich will be reseeded */
-       .ru_max = 1000000000,   /* Uniq cycle, avoid blackjack prediction */
-       .ru_gen = 2,            /* Starting generator */
-       .ru_n = 2147483629,     /* RU_N-1 = 2^2*3^2*59652323 */
-       .ru_agen = 7,           /* determine ru_a as RU_AGEN^(2*rand) */
-       .ru_m = 1836660096,     /* RU_M = 2^7*3^15 - don't change */
-       .ru_pfacts = { 2, 3, 59652323, 0 },     /* factors of ru_n */
-};
-
-static struct randomtab randomtab_20 = {
-       .ru_bits = 20,          /* resulting bits */
-       .ru_out = 180,          /* Time after wich will be reseeded */
-       .ru_max = 200000,       /* Uniq cycle, avoid blackjack prediction */
-       .ru_gen = 2,            /* Starting generator */
-       .ru_n = 524269,         /* RU_N-1 = 2^2*3^2*14563 */
-       .ru_agen = 7,           /* determine ru_a as RU_AGEN^(2*rand) */
-       .ru_m = 279936,         /* RU_M = 2^7*3^7 - don't change */
-       .ru_pfacts = { 2, 3, 14563, 0 },        /* factors of ru_n */
-};
-
-static u_int32_t pmod(u_int32_t, u_int32_t, u_int32_t);
-static void initid(struct randomtab *);
-static u_int32_t randomid(struct randomtab *);
-
-/*
- * Do a fast modular exponation, returned value will be in the range
- * of 0 - (mod-1)
- */
-
-static u_int32_t
-pmod(u_int32_t gen, u_int32_t expo, u_int32_t mod)
-{
-       u_int64_t s, t, u;
-
-       s = 1;
-       t = gen;
-       u = expo;
-
-       while (u) {
-               if (u & 1)
-                       s = (s * t) % mod;
-               u >>= 1;
-               t = (t * t) % mod;
-       }
-       return (s);
-}
-
-/*
- * Initializes the seed and chooses a suitable generator. Also toggles
- * the msb flag. The msb flag is used to generate two distinct
- * cycles of random numbers and thus avoiding reuse of ids.
- *
- * This function is called from id_randomid() when needed, an
- * application does not have to worry about it.
- */
-static void
-initid(struct randomtab *p)
-{
-       u_int32_t j, i;
-       int noprime = 1;
-
-       p->ru_x = cprng_fast32() % p->ru_m;
-
-       /* (bits - 1) bits of random seed */
-       p->ru_seed = cprng_fast32() & (~0U >> (32 - p->ru_bits + 1));
-       p->ru_seed2 = cprng_fast32() & (~0U >> (32 - p->ru_bits + 1));
-
-       /* Determine the LCG we use */
-       p->ru_b = (cprng_fast32() & (~0U >> (32 - p->ru_bits))) | 1;
-       p->ru_a = pmod(p->ru_agen,
-           (cprng_fast32() & (~0U >> (32 - p->ru_bits))) & (~1U), p->ru_m);
-       while (p->ru_b % 3 == 0)
-               p->ru_b += 2;
-
-       j = cprng_fast32() % p->ru_n;
-
-       /*
-        * Do a fast gcd(j, RU_N - 1), so we can find a j with
-        * gcd(j, RU_N - 1) == 1, giving a new generator for
-        * RU_GEN^j mod RU_N
-        */
-       while (noprime) {
-               for (i = 0; p->ru_pfacts[i] > 0; i++)
-                       if (j % p->ru_pfacts[i] == 0)
-                               break;
-
-               if (p->ru_pfacts[i] == 0)
-                       noprime = 0;
-               else
-                       j = (j + 1) % p->ru_n;
-       }
-
-       p->ru_g = pmod(p->ru_gen, j, p->ru_n);
-       p->ru_counter = 0;
-
-       p->ru_reseed = time_uptime + p->ru_out;
-       p->ru_msb = p->ru_msb ? 0 : (1U << (p->ru_bits - 1));
-}
-
-static u_int32_t
-randomid(struct randomtab *p)
-{
-       int i, n;
-
-       if (p->ru_counter >= p->ru_max || time_uptime > p->ru_reseed)
-               initid(p);
-
-       /* Skip a random number of ids */
-       n = cprng_fast32() & 0x3;
-       if (p->ru_counter + n >= p->ru_max)
-               initid(p);
-
-       for (i = 0; i <= n; i++) {
-               /* Linear Congruential Generator */
-               p->ru_x = ((u_int64_t)p->ru_a * p->ru_x + p->ru_b) % p->ru_m;
-       }
-
-       p->ru_counter += i;
-
-       return (p->ru_seed ^ pmod(p->ru_g, p->ru_seed2 + p->ru_x, p->ru_n)) |
-           p->ru_msb;
-}
-
-u_int32_t
+uint32_t
 ip6_randomid(void)
 {
 
-       return randomid(&randomtab_32);
+       return cprng_fast32();
 }
 
-u_int32_t
+uint32_t
 ip6_randomflowlabel(void)
 {
 
-       return randomid(&randomtab_20) & 0xfffff;
+       return cprng_fast32() & 0xfffff;
 }



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