inet/ipf/drand48.c

ab073b324433ebc8947d28ade932d29d0e809795dr/*
ab073b324433ebc8947d28ade932d29d0e809795dr * CDDL HEADER START
ab073b324433ebc8947d28ade932d29d0e809795dr *
ab073b324433ebc8947d28ade932d29d0e809795dr * The contents of this file are subject to the terms of the
ab073b324433ebc8947d28ade932d29d0e809795dr * Common Development and Distribution License (the "License").
ab073b324433ebc8947d28ade932d29d0e809795dr * You may not use this file except in compliance with the License.
ab073b324433ebc8947d28ade932d29d0e809795dr *
ab073b324433ebc8947d28ade932d29d0e809795dr * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
ab073b324433ebc8947d28ade932d29d0e809795dr * or http://www.opensolaris.org/os/licensing.
ab073b324433ebc8947d28ade932d29d0e809795dr * See the License for the specific language governing permissions
ab073b324433ebc8947d28ade932d29d0e809795dr * and limitations under the License.
ab073b324433ebc8947d28ade932d29d0e809795dr *
ab073b324433ebc8947d28ade932d29d0e809795dr * When distributing Covered Code, include this CDDL HEADER in each
ab073b324433ebc8947d28ade932d29d0e809795dr * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
ab073b324433ebc8947d28ade932d29d0e809795dr * If applicable, add the following below this CDDL HEADER, with the
ab073b324433ebc8947d28ade932d29d0e809795dr * fields enclosed by brackets "[]" replaced with your own identifying
ab073b324433ebc8947d28ade932d29d0e809795dr * information: Portions Copyright [yyyy] [name of copyright owner]
ab073b324433ebc8947d28ade932d29d0e809795dr *
ab073b324433ebc8947d28ade932d29d0e809795dr * CDDL HEADER END
ab073b324433ebc8947d28ade932d29d0e809795dr */
ab073b324433ebc8947d28ade932d29d0e809795dr
ab073b324433ebc8947d28ade932d29d0e809795dr/*
62d17c5fefb1ca81dc75288f899e19485b3f72f1Darren Reed * Copyright 2009 Sun Microsystems, Inc.  All rights reserved.
ab073b324433ebc8947d28ade932d29d0e809795dr * Use is subject to license terms.
ab073b324433ebc8947d28ade932d29d0e809795dr */
ab073b324433ebc8947d28ade932d29d0e809795dr
ab073b324433ebc8947d28ade932d29d0e809795dr/*  Copyright (c) 1988 AT&T */
ab073b324433ebc8947d28ade932d29d0e809795dr/*    All Rights Reserved   */
ab073b324433ebc8947d28ade932d29d0e809795dr
ab073b324433ebc8947d28ade932d29d0e809795dr/*
ab073b324433ebc8947d28ade932d29d0e809795dr *  drand48, etc. pseudo-random number generator
ab073b324433ebc8947d28ade932d29d0e809795dr *  This implementation assumes unsigned short integers of at least
ab073b324433ebc8947d28ade932d29d0e809795dr *  16 bits, long integers of at least 32 bits, and ignores
ab073b324433ebc8947d28ade932d29d0e809795dr *  overflows on adding or multiplying two unsigned integers.
ab073b324433ebc8947d28ade932d29d0e809795dr *  Two's-complement representation is assumed in a few places.
ab073b324433ebc8947d28ade932d29d0e809795dr *  Some extra masking is done if unsigneds are exactly 16 bits
ab073b324433ebc8947d28ade932d29d0e809795dr *  or longs are exactly 32 bits, but so what?
ab073b324433ebc8947d28ade932d29d0e809795dr *  An assembly-language implementation would run significantly faster.
ab073b324433ebc8947d28ade932d29d0e809795dr */
ab073b324433ebc8947d28ade932d29d0e809795dr/*
ab073b324433ebc8947d28ade932d29d0e809795dr *  New assumptions (supercede those stated above) for 64-bit work.
ab073b324433ebc8947d28ade932d29d0e809795dr *  Longs are now 64 bits, and we are bound by standards to return
ab073b324433ebc8947d28ade932d29d0e809795dr *  type long, hovever all internal calculations where long was
ab073b324433ebc8947d28ade932d29d0e809795dr *  previously used (32 bit precision) are now using the int32_t
ab073b324433ebc8947d28ade932d29d0e809795dr *  type (32 bit precision in both ILP32 and LP64 worlds).
ab073b324433ebc8947d28ade932d29d0e809795dr */
ab073b324433ebc8947d28ade932d29d0e809795dr
ab073b324433ebc8947d28ade932d29d0e809795dr#include <sys/mutex.h>
ab073b324433ebc8947d28ade932d29d0e809795dr
ab073b324433ebc8947d28ade932d29d0e809795drstatic kmutex_t seed_lock;
ab073b324433ebc8947d28ade932d29d0e809795drstatic int  init48done = 0;
ab073b324433ebc8947d28ade932d29d0e809795dr
ab073b324433ebc8947d28ade932d29d0e809795dr#define EXPORT0(TYPE, fn, fnu)  TYPE fn() { \
ab073b324433ebc8947d28ade932d29d0e809795dr    TYPE res; \
ab073b324433ebc8947d28ade932d29d0e809795dr    mutex_enter(&seed_lock); \
ab073b324433ebc8947d28ade932d29d0e809795dr    res = fnu(); \
ab073b324433ebc8947d28ade932d29d0e809795dr    mutex_exit(&seed_lock); \
ab073b324433ebc8947d28ade932d29d0e809795dr    return (res); }
ab073b324433ebc8947d28ade932d29d0e809795dr#define EXPORT1(TYPE, fn, fnu)  TYPE fn(unsigned short xsubi[3]) { \
ab073b324433ebc8947d28ade932d29d0e809795dr    TYPE res; \
ab073b324433ebc8947d28ade932d29d0e809795dr    mutex_enter(&seed_lock); \
ab073b324433ebc8947d28ade932d29d0e809795dr    res = fnu(xsubi); \
ab073b324433ebc8947d28ade932d29d0e809795dr    mutex_exit(&seed_lock); \
ab073b324433ebc8947d28ade932d29d0e809795dr    return (res); }
ab073b324433ebc8947d28ade932d29d0e809795dr
ab073b324433ebc8947d28ade932d29d0e809795dr#define N   16
ab073b324433ebc8947d28ade932d29d0e809795dr#define MASK    ((unsigned)(1 << (N - 1)) + (1 << (N - 1)) - 1)
ab073b324433ebc8947d28ade932d29d0e809795dr#define LOW(x)  ((unsigned)(x) & MASK)
ab073b324433ebc8947d28ade932d29d0e809795dr#define HIGH(x) LOW((x) >> N)
ab073b324433ebc8947d28ade932d29d0e809795dr#define MUL(x, y, z)    { int32_t l = (int32_t)(x) * (int32_t)(y); \
ab073b324433ebc8947d28ade932d29d0e809795dr        (z)[0] = LOW(l); (z)[1] = HIGH(l); }
ab073b324433ebc8947d28ade932d29d0e809795dr#define CARRY(x, y) ((int32_t)(x) + (int32_t)(y) > MASK)
ab073b324433ebc8947d28ade932d29d0e809795dr#define ADDEQU(x, y, z) (z = CARRY(x, (y)), x = LOW(x + (y)))
ab073b324433ebc8947d28ade932d29d0e809795dr#define X0  0x330E
ab073b324433ebc8947d28ade932d29d0e809795dr#define X1  0xABCD
ab073b324433ebc8947d28ade932d29d0e809795dr#define X2  0x1234
ab073b324433ebc8947d28ade932d29d0e809795dr#define A0  0xE66D
ab073b324433ebc8947d28ade932d29d0e809795dr#define A1  0xDEEC
ab073b324433ebc8947d28ade932d29d0e809795dr#define A2  0x5
ab073b324433ebc8947d28ade932d29d0e809795dr#define C   0xB
ab073b324433ebc8947d28ade932d29d0e809795dr#define SET3(x, x0, x1, x2) ((x)[0] = (x0), (x)[1] = (x1), (x)[2] = (x2))
ab073b324433ebc8947d28ade932d29d0e809795dr#define SETLOW(x, y, n) SET3(x, LOW((y)[n]), LOW((y)[(n)+1]), LOW((y)[(n)+2]))
ab073b324433ebc8947d28ade932d29d0e809795dr#define SEED(x0, x1, x2) (SET3(x, x0, x1, x2), SET3(a, A0, A1, A2), c = C)
ab073b324433ebc8947d28ade932d29d0e809795dr#define REST(v) for (i = 0; i < 3; i++) { xsubi[i] = x[i]; x[i] = temp[i]; } \
ab073b324433ebc8947d28ade932d29d0e809795dr        return (v)
ab073b324433ebc8947d28ade932d29d0e809795dr#define NEST(TYPE, f, F) static TYPE f(unsigned short *xsubi) { \
ab073b324433ebc8947d28ade932d29d0e809795dr    int i; TYPE v; unsigned temp[3]; \
ab073b324433ebc8947d28ade932d29d0e809795dr    for (i = 0; i < 3; i++) { temp[i] = x[i]; x[i] = LOW(xsubi[i]); }  \
ab073b324433ebc8947d28ade932d29d0e809795dr    v = F(); REST(v); }
ab073b324433ebc8947d28ade932d29d0e809795dr
ab073b324433ebc8947d28ade932d29d0e809795dr/* Way ugly solution to problem names, but it works */
ab073b324433ebc8947d28ade932d29d0e809795dr#define x   _drand48_x
ab073b324433ebc8947d28ade932d29d0e809795dr#define a   _drand48_a
ab073b324433ebc8947d28ade932d29d0e809795dr#define c   _drand48_c
ab073b324433ebc8947d28ade932d29d0e809795dr/* End way ugly */
ab073b324433ebc8947d28ade932d29d0e809795drstatic unsigned x[3] = { X0, X1, X2 }, a[3] = { A0, A1, A2 }, c = C;
ab073b324433ebc8947d28ade932d29d0e809795drstatic unsigned short lastx[3];
ab073b324433ebc8947d28ade932d29d0e809795drstatic void next(void);
ab073b324433ebc8947d28ade932d29d0e809795dr
ab073b324433ebc8947d28ade932d29d0e809795drstatic long
ab073b324433ebc8947d28ade932d29d0e809795dripf_r_lrand48_u(void)
ab073b324433ebc8947d28ade932d29d0e809795dr{
ab073b324433ebc8947d28ade932d29d0e809795dr    next();
ab073b324433ebc8947d28ade932d29d0e809795dr    return ((long)((int32_t)x[2] << (N - 1)) + (x[1] >> 1));
ab073b324433ebc8947d28ade932d29d0e809795dr}
ab073b324433ebc8947d28ade932d29d0e809795dr
ab073b324433ebc8947d28ade932d29d0e809795drstatic void
ab073b324433ebc8947d28ade932d29d0e809795drinit48(void)
ab073b324433ebc8947d28ade932d29d0e809795dr{
ab073b324433ebc8947d28ade932d29d0e809795dr    mutex_init(&seed_lock, 0L, MUTEX_DRIVER, 0L);
ab073b324433ebc8947d28ade932d29d0e809795dr    init48done = 1;
ab073b324433ebc8947d28ade932d29d0e809795dr}
ab073b324433ebc8947d28ade932d29d0e809795dr
ab073b324433ebc8947d28ade932d29d0e809795drstatic long
ab073b324433ebc8947d28ade932d29d0e809795dripf_r_mrand48_u(void)
ab073b324433ebc8947d28ade932d29d0e809795dr{
ab073b324433ebc8947d28ade932d29d0e809795dr    next();
ab073b324433ebc8947d28ade932d29d0e809795dr    return ((long)((int32_t)x[2] << N) + x[1]);
ab073b324433ebc8947d28ade932d29d0e809795dr}
ab073b324433ebc8947d28ade932d29d0e809795dr
ab073b324433ebc8947d28ade932d29d0e809795drstatic void
ab073b324433ebc8947d28ade932d29d0e809795drnext(void)
ab073b324433ebc8947d28ade932d29d0e809795dr{
ab073b324433ebc8947d28ade932d29d0e809795dr    unsigned p[2], q[2], r[2], carry0, carry1;
ab073b324433ebc8947d28ade932d29d0e809795dr
ab073b324433ebc8947d28ade932d29d0e809795dr    MUL(a[0], x[0], p);
ab073b324433ebc8947d28ade932d29d0e809795dr    ADDEQU(p[0], c, carry0);
ab073b324433ebc8947d28ade932d29d0e809795dr    ADDEQU(p[1], carry0, carry1);
ab073b324433ebc8947d28ade932d29d0e809795dr    MUL(a[0], x[1], q);
ab073b324433ebc8947d28ade932d29d0e809795dr    ADDEQU(p[1], q[0], carry0);
ab073b324433ebc8947d28ade932d29d0e809795dr    MUL(a[1], x[0], r);
ab073b324433ebc8947d28ade932d29d0e809795dr    x[2] = LOW(carry0 + carry1 + CARRY(p[1], r[0]) + q[1] + r[1] +
ab073b324433ebc8947d28ade932d29d0e809795dr        a[0] * x[2] + a[1] * x[1] + a[2] * x[0]);
ab073b324433ebc8947d28ade932d29d0e809795dr    x[1] = LOW(p[1] + r[0]);
ab073b324433ebc8947d28ade932d29d0e809795dr    x[0] = LOW(p[0]);
ab073b324433ebc8947d28ade932d29d0e809795dr}
ab073b324433ebc8947d28ade932d29d0e809795dr
ab073b324433ebc8947d28ade932d29d0e809795drvoid
ab073b324433ebc8947d28ade932d29d0e809795dripf_r_srand48(long seedval)
ab073b324433ebc8947d28ade932d29d0e809795dr{
ab073b324433ebc8947d28ade932d29d0e809795dr    int32_t fixseed = (int32_t)seedval; /* limit to 32 bits */
ab073b324433ebc8947d28ade932d29d0e809795dr
ab073b324433ebc8947d28ade932d29d0e809795dr    if (init48done == 0)
ab073b324433ebc8947d28ade932d29d0e809795dr        init48();
ab073b324433ebc8947d28ade932d29d0e809795dr    mutex_enter(&seed_lock);
ab073b324433ebc8947d28ade932d29d0e809795dr    SEED(X0, LOW(fixseed), HIGH(fixseed));
ab073b324433ebc8947d28ade932d29d0e809795dr    mutex_exit(&seed_lock);
ab073b324433ebc8947d28ade932d29d0e809795dr}
ab073b324433ebc8947d28ade932d29d0e809795dr
ab073b324433ebc8947d28ade932d29d0e809795drEXPORT0(long, ipf_r_lrand48, ipf_r_lrand48_u)
ab073b324433ebc8947d28ade932d29d0e809795dr
ab073b324433ebc8947d28ade932d29d0e809795dr#include <sys/random.h>
ab073b324433ebc8947d28ade932d29d0e809795dr
ab073b324433ebc8947d28ade932d29d0e809795drunsigned
ab073b324433ebc8947d28ade932d29d0e809795dripf_random()
ab073b324433ebc8947d28ade932d29d0e809795dr{
ab073b324433ebc8947d28ade932d29d0e809795dr    static int seeded = 0;
ab073b324433ebc8947d28ade932d29d0e809795dr
ab073b324433ebc8947d28ade932d29d0e809795dr    if (seeded == 0) {
ab073b324433ebc8947d28ade932d29d0e809795dr        long seed;
ab073b324433ebc8947d28ade932d29d0e809795dr
ab073b324433ebc8947d28ade932d29d0e809795dr        /*
ab073b324433ebc8947d28ade932d29d0e809795dr         * Keep reseeding until some good randomness comes from the
ab073b324433ebc8947d28ade932d29d0e809795dr         * kernel. One of two things will happen: it will succeed or
ab073b324433ebc8947d28ade932d29d0e809795dr         * it will fail (with poor randomness), thus creating NAT
ab073b324433ebc8947d28ade932d29d0e809795dr         * sessions will be "slow" until enough randomness is gained
ab073b324433ebc8947d28ade932d29d0e809795dr         * to not need to get more. It isn't necessary to initialise
ab073b324433ebc8947d28ade932d29d0e809795dr         * seed as it will just pickup whatever random garbage has
ab073b324433ebc8947d28ade932d29d0e809795dr         * been left on the heap and that's good enough until we
ab073b324433ebc8947d28ade932d29d0e809795dr         * get some good garbage.
ab073b324433ebc8947d28ade932d29d0e809795dr         */
ab073b324433ebc8947d28ade932d29d0e809795dr        if (random_get_bytes((uint8_t *)&seed, sizeof (seed)) == 0)
ab073b324433ebc8947d28ade932d29d0e809795dr            seeded = 1;
ab073b324433ebc8947d28ade932d29d0e809795dr        ipf_r_srand48(seed);
ab073b324433ebc8947d28ade932d29d0e809795dr    }
ab073b324433ebc8947d28ade932d29d0e809795dr
ab073b324433ebc8947d28ade932d29d0e809795dr    return (unsigned)ipf_r_lrand48();
ab073b324433ebc8947d28ade932d29d0e809795dr}