2003-10-01 15:13:29 +00:00
|
|
|
/* $KAME: ip6_id.c,v 1.13 2003/09/16 09:11:19 itojun Exp $ */
|
|
|
|
/* $OpenBSD: ip_id.c,v 1.6 2002/03/15 18:19:52 millert Exp $ */
|
|
|
|
/* $FreeBSD$ */
|
|
|
|
|
|
|
|
/*
|
|
|
|
* Copyright (C) 2003 WIDE Project.
|
|
|
|
* All rights reserved.
|
|
|
|
*
|
|
|
|
* 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.
|
|
|
|
* 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>
|
|
|
|
* All rights reserved.
|
|
|
|
*
|
|
|
|
* Theo de Raadt <deraadt@openbsd.org> 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.
|
|
|
|
* 3. All advertising materials mentioning features or use of this software
|
|
|
|
* must display the following acknowledgement:
|
|
|
|
* This product includes software developed by Niels Provos.
|
|
|
|
* 4. The name of the author may not be used to endorse or promote products
|
|
|
|
* derived from this software without specific prior written permission.
|
|
|
|
*
|
|
|
|
* 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)
|
|
|
|
*
|
|
|
|
* Effectivly 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.
|
|
|
|
*/
|
|
|
|
|
2003-10-01 17:28:42 +00:00
|
|
|
#include "opt_random_ip_id.h"
|
|
|
|
|
2003-10-01 15:13:29 +00:00
|
|
|
#include <sys/types.h>
|
|
|
|
#include <sys/param.h>
|
|
|
|
#include <sys/kernel.h>
|
|
|
|
#include <sys/socket.h>
|
|
|
|
#include <sys/libkern.h>
|
|
|
|
|
|
|
|
#include <net/if.h>
|
|
|
|
#include <net/route.h>
|
|
|
|
#include <netinet/in.h>
|
|
|
|
#include <netinet/ip6.h>
|
|
|
|
#include <netinet6/ip6_var.h>
|
|
|
|
|
2003-10-01 16:22:58 +00:00
|
|
|
#ifdef RANDOM_IP_ID
|
|
|
|
|
2003-10-01 15:13:29 +00:00
|
|
|
#ifndef INT32_MAX
|
|
|
|
#define INT32_MAX 0x7fffffffU
|
|
|
|
#endif
|
|
|
|
|
|
|
|
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 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 = {
|
|
|
|
32, /* resulting bits */
|
|
|
|
180, /* Time after wich will be reseeded */
|
|
|
|
1000000000, /* Uniq cycle, avoid blackjack prediction */
|
|
|
|
2, /* Starting generator */
|
|
|
|
2147483629, /* RU_N-1 = 2^2*3^2*59652323 */
|
|
|
|
7, /* determine ru_a as RU_AGEN^(2*rand) */
|
|
|
|
1836660096, /* RU_M = 2^7*3^15 - don't change */
|
|
|
|
{ 2, 3, 59652323, 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);
|
|
|
|
}
|
|
|
|
|
|
|
|
/*
|
|
|
|
* Initalizes 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 = arc4random() % p->ru_m;
|
|
|
|
|
|
|
|
/* (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;
|
|
|
|
p->ru_a = pmod(p->ru_agen,
|
|
|
|
(arc4random() & (~0U >> (32 - p->ru_bits))) & (~1U), p->ru_m);
|
|
|
|
while (p->ru_b % 3 == 0)
|
|
|
|
p->ru_b += 2;
|
|
|
|
|
|
|
|
j = arc4random() % 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->pfacts[i] > 0; i++)
|
|
|
|
if (j % p->pfacts[i] == 0)
|
|
|
|
break;
|
|
|
|
|
|
|
|
if (p->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_second + 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;
|
|
|
|
u_int32_t tmp;
|
|
|
|
|
|
|
|
if (p->ru_counter >= p->ru_max || time_second > p->ru_reseed)
|
|
|
|
initid(p);
|
|
|
|
|
|
|
|
tmp = arc4random();
|
|
|
|
|
|
|
|
/* Skip a random number of ids */
|
|
|
|
n = tmp & 0x3; tmp = tmp >> 2;
|
|
|
|
if (p->ru_counter + n >= p->ru_max)
|
|
|
|
initid(p);
|
|
|
|
|
|
|
|
for (i = 0; i <= n; i++) {
|
|
|
|
/* Linear Congruential Generator */
|
|
|
|
p->ru_x = (u_int32_t)((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
|
|
|
|
ip6_randomid(void)
|
|
|
|
{
|
|
|
|
|
|
|
|
return randomid(&randomtab_32);
|
|
|
|
}
|
2003-10-01 16:22:58 +00:00
|
|
|
|
2003-10-01 21:24:28 +00:00
|
|
|
u_int32_t
|
|
|
|
ip6_randomflowlabel(void)
|
|
|
|
{
|
|
|
|
|
|
|
|
return randomid(&randomtab_20) & 0xfffff;
|
|
|
|
}
|
|
|
|
|
2003-10-01 16:22:58 +00:00
|
|
|
#endif /* RANDOM_IP_ID */
|