+++ /dev/null
-/*****************************************************************************
-* randm.c - Random number generator program file.
-*
-* Copyright (c) 2003 by Marc Boucher, Services Informatiques (MBSI) inc.
-* Copyright (c) 1998 by Global Election Systems Inc.
-*
-* The authors hereby grant permission to use, copy, modify, distribute,
-* and license this software and its documentation for any purpose, provided
-* that existing copyright notices are retained in all copies and that this
-* notice and the following disclaimer are included verbatim in any
-* distributions. No written agreement, license, or royalty fee is required
-* for any of the authorized uses.
-*
-* THIS SOFTWARE IS PROVIDED BY THE 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 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.
-*
-******************************************************************************
-* REVISION HISTORY
-*
-* 03-01-01 Marc Boucher <marc@mbsi.ca>
-* Ported to lwIP.
-* 98-06-03 Guy Lancaster <lancasterg@acm.org>, Global Election Systems Inc.
-* Extracted from avos.
-*****************************************************************************/
-
-#include "lwip/opt.h"
-
-#if PPP_SUPPORT /* don't build if not configured for use in lwipopts.h */
-
-#include "md5.h"
-#include "randm.h"
-
-#include "ppp_impl.h"
-#include "pppdebug.h"
-
-#include <string.h>
-
-#if MD5_SUPPORT /* this module depends on MD5 */
-#define RANDPOOLSZ 16 /* Bytes stored in the pool of randomness. */
-
-/*****************************/
-/*** LOCAL DATA STRUCTURES ***/
-/*****************************/
-static char randPool[RANDPOOLSZ]; /* Pool of randomness. */
-static long randCount = 0; /* Pseudo-random incrementer */
-
-
-/***********************************/
-/*** PUBLIC FUNCTION DEFINITIONS ***/
-/***********************************/
-/*
- * Initialize the random number generator.
- *
- * Since this is to be called on power up, we don't have much
- * system randomess to work with. Here all we use is the
- * real-time clock. We'll accumulate more randomness as soon
- * as things start happening.
- */
-void
-avRandomInit()
-{
- avChurnRand(NULL, 0);
-}
-
-/*
- * Churn the randomness pool on a random event. Call this early and often
- * on random and semi-random system events to build randomness in time for
- * usage. For randomly timed events, pass a null pointer and a zero length
- * and this will use the system timer and other sources to add randomness.
- * If new random data is available, pass a pointer to that and it will be
- * included.
- *
- * Ref: Applied Cryptography 2nd Ed. by Bruce Schneier p. 427
- */
-void
-avChurnRand(char *randData, u32_t randLen)
-{
- MD5_CTX md5;
-
- /* LWIP_DEBUGF(LOG_INFO, ("churnRand: %u@%P\n", randLen, randData)); */
- MD5Init(&md5);
- MD5Update(&md5, (u_char *)randPool, sizeof(randPool));
- if (randData) {
- MD5Update(&md5, (u_char *)randData, randLen);
- } else {
- struct {
- /* INCLUDE fields for any system sources of randomness */
- char foobar;
- } sysData;
-
- /* Load sysData fields here. */
- MD5Update(&md5, (u_char *)&sysData, sizeof(sysData));
- }
- MD5Final((u_char *)randPool, &md5);
-/* LWIP_DEBUGF(LOG_INFO, ("churnRand: -> 0\n")); */
-}
-
-/*
- * Use the random pool to generate random data. This degrades to pseudo
- * random when used faster than randomness is supplied using churnRand().
- * Note: It's important that there be sufficient randomness in randPool
- * before this is called for otherwise the range of the result may be
- * narrow enough to make a search feasible.
- *
- * Ref: Applied Cryptography 2nd Ed. by Bruce Schneier p. 427
- *
- * XXX Why does he not just call churnRand() for each block? Probably
- * so that you don't ever publish the seed which could possibly help
- * predict future values.
- * XXX Why don't we preserve md5 between blocks and just update it with
- * randCount each time? Probably there is a weakness but I wish that
- * it was documented.
- */
-void
-avGenRand(char *buf, u32_t bufLen)
-{
- MD5_CTX md5;
- u_char tmp[16];
- u32_t n;
-
- while (bufLen > 0) {
- n = LWIP_MIN(bufLen, RANDPOOLSZ);
- MD5Init(&md5);
- MD5Update(&md5, (u_char *)randPool, sizeof(randPool));
- MD5Update(&md5, (u_char *)&randCount, sizeof(randCount));
- MD5Final(tmp, &md5);
- randCount++;
- MEMCPY(buf, tmp, n);
- buf += n;
- bufLen -= n;
- }
-}
-
-/*
- * Return a new random number.
- */
-u32_t
-avRandom()
-{
- u32_t newRand;
-
- avGenRand((char *)&newRand, sizeof(newRand));
-
- return newRand;
-}
-
-#else /* MD5_SUPPORT */
-
-/*****************************/
-/*** LOCAL DATA STRUCTURES ***/
-/*****************************/
-static int avRandomized = 0; /* Set when truely randomized. */
-static u32_t avRandomSeed = 0; /* Seed used for random number generation. */
-
-
-/***********************************/
-/*** PUBLIC FUNCTION DEFINITIONS ***/
-/***********************************/
-/*
- * Initialize the random number generator.
- *
- * Here we attempt to compute a random number seed but even if
- * it isn't random, we'll randomize it later.
- *
- * The current method uses the fields from the real time clock,
- * the idle process counter, the millisecond counter, and the
- * hardware timer tick counter. When this is invoked
- * in startup(), then the idle counter and timer values may
- * repeat after each boot and the real time clock may not be
- * operational. Thus we call it again on the first random
- * event.
- */
-void
-avRandomInit()
-{
-#if 0
- /* Get a pointer into the last 4 bytes of clockBuf. */
- u32_t *lptr1 = (u32_t *)((char *)&clockBuf[3]);
-
- /*
- * Initialize our seed using the real-time clock, the idle
- * counter, the millisecond timer, and the hardware timer
- * tick counter. The real-time clock and the hardware
- * tick counter are the best sources of randomness but
- * since the tick counter is only 16 bit (and truncated
- * at that), the idle counter and millisecond timer
- * (which may be small values) are added to help
- * randomize the lower 16 bits of the seed.
- */
- readClk();
- avRandomSeed += *(u32_t *)clockBuf + *lptr1 + OSIdleCtr
- + ppp_mtime() + ((u32_t)TM1 << 16) + TM1;
-#else
- avRandomSeed += sys_jiffies(); /* XXX */
-#endif
-
- /* Initialize the Borland random number generator. */
- srand((unsigned)avRandomSeed);
-}
-
-/*
- * Randomize our random seed value. Here we use the fact that
- * this function is called at *truely random* times by the polling
- * and network functions. Here we only get 16 bits of new random
- * value but we use the previous value to randomize the other 16
- * bits.
- */
-void
-avRandomize(void)
-{
- static u32_t last_jiffies;
-
- if (!avRandomized) {
- avRandomized = !0;
- avRandomInit();
- /* The initialization function also updates the seed. */
- } else {
- /* avRandomSeed += (avRandomSeed << 16) + TM1; */
- avRandomSeed += (sys_jiffies() - last_jiffies); /* XXX */
- }
- last_jiffies = sys_jiffies();
-}
-
-/*
- * Return a new random number.
- * Here we use the Borland rand() function to supply a pseudo random
- * number which we make truely random by combining it with our own
- * seed which is randomized by truely random events.
- * Thus the numbers will be truely random unless there have been no
- * operator or network events in which case it will be pseudo random
- * seeded by the real time clock.
- */
-u32_t
-avRandom()
-{
- return ((((u32_t)rand() << 16) + rand()) + avRandomSeed);
-}
-
-#endif /* MD5_SUPPORT */
-
-#endif /* PPP_SUPPORT */
projects / reactos.git / blobdiff