Nino Der Kinderen / Mbed 2 deprecated InetTest

Embedded C project:18/12/2014

Dependencies:   DS1307 TextLCD mbed

NetServices/lwip/netif/ppp/randm.c@0:8d87bc453349, 2014-12-18 (annotated)

Committer:
ninoderkinderen
Date:
Thu Dec 18 09:35:49 2014 +0000
Revision:
0:8d87bc453349
Programma embedded C

Who changed what in which revision?

UserRevisionLine numberNew contents of line
ninoderkinderen 0:8d87bc453349 1 /*****************************************************************************
ninoderkinderen 0:8d87bc453349 2 * randm.c - Random number generator program file.
ninoderkinderen 0:8d87bc453349 3 *
ninoderkinderen 0:8d87bc453349 4 * Copyright (c) 2003 by Marc Boucher, Services Informatiques (MBSI) inc.
ninoderkinderen 0:8d87bc453349 5 * Copyright (c) 1998 by Global Election Systems Inc.
ninoderkinderen 0:8d87bc453349 6 *
ninoderkinderen 0:8d87bc453349 7 * The authors hereby grant permission to use, copy, modify, distribute,
ninoderkinderen 0:8d87bc453349 8 * and license this software and its documentation for any purpose, provided
ninoderkinderen 0:8d87bc453349 9 * that existing copyright notices are retained in all copies and that this
ninoderkinderen 0:8d87bc453349 10 * notice and the following disclaimer are included verbatim in any
ninoderkinderen 0:8d87bc453349 11 * distributions. No written agreement, license, or royalty fee is required
ninoderkinderen 0:8d87bc453349 12 * for any of the authorized uses.
ninoderkinderen 0:8d87bc453349 13 *
ninoderkinderen 0:8d87bc453349 14 * THIS SOFTWARE IS PROVIDED BY THE CONTRIBUTORS *AS IS* AND ANY EXPRESS OR
ninoderkinderen 0:8d87bc453349 15 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
ninoderkinderen 0:8d87bc453349 16 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
ninoderkinderen 0:8d87bc453349 17 * IN NO EVENT SHALL THE CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
ninoderkinderen 0:8d87bc453349 18 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
ninoderkinderen 0:8d87bc453349 19 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
ninoderkinderen 0:8d87bc453349 20 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
ninoderkinderen 0:8d87bc453349 21 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
ninoderkinderen 0:8d87bc453349 22 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
ninoderkinderen 0:8d87bc453349 23 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
ninoderkinderen 0:8d87bc453349 24 *
ninoderkinderen 0:8d87bc453349 25 ******************************************************************************
ninoderkinderen 0:8d87bc453349 26 * REVISION HISTORY
ninoderkinderen 0:8d87bc453349 27 *
ninoderkinderen 0:8d87bc453349 28 * 03-01-01 Marc Boucher <marc@mbsi.ca>
ninoderkinderen 0:8d87bc453349 29 * Ported to lwIP.
ninoderkinderen 0:8d87bc453349 30 * 98-06-03 Guy Lancaster <lancasterg@acm.org>, Global Election Systems Inc.
ninoderkinderen 0:8d87bc453349 31 * Extracted from avos.
ninoderkinderen 0:8d87bc453349 32 *****************************************************************************/
ninoderkinderen 0:8d87bc453349 33
ninoderkinderen 0:8d87bc453349 34 #include "lwip/opt.h"
ninoderkinderen 0:8d87bc453349 35
ninoderkinderen 0:8d87bc453349 36 #if PPP_SUPPORT /* don't build if not configured for use in lwipopts.h */
ninoderkinderen 0:8d87bc453349 37
ninoderkinderen 0:8d87bc453349 38 #include "md5.h"
ninoderkinderen 0:8d87bc453349 39 #include "randm.h"
ninoderkinderen 0:8d87bc453349 40
ninoderkinderen 0:8d87bc453349 41 #include "ppp.h"
ninoderkinderen 0:8d87bc453349 42 #include "pppdebug.h"
ninoderkinderen 0:8d87bc453349 43
ninoderkinderen 0:8d87bc453349 44 #include <string.h>
ninoderkinderen 0:8d87bc453349 45
ninoderkinderen 0:8d87bc453349 46 #if MD5_SUPPORT /* this module depends on MD5 */
ninoderkinderen 0:8d87bc453349 47 #define RANDPOOLSZ 16 /* Bytes stored in the pool of randomness. */
ninoderkinderen 0:8d87bc453349 48
ninoderkinderen 0:8d87bc453349 49 /*****************************/
ninoderkinderen 0:8d87bc453349 50 /*** LOCAL DATA STRUCTURES ***/
ninoderkinderen 0:8d87bc453349 51 /*****************************/
ninoderkinderen 0:8d87bc453349 52 static char randPool[RANDPOOLSZ]; /* Pool of randomness. */
ninoderkinderen 0:8d87bc453349 53 static long randCount = 0; /* Pseudo-random incrementer */
ninoderkinderen 0:8d87bc453349 54
ninoderkinderen 0:8d87bc453349 55
ninoderkinderen 0:8d87bc453349 56 /***********************************/
ninoderkinderen 0:8d87bc453349 57 /*** PUBLIC FUNCTION DEFINITIONS ***/
ninoderkinderen 0:8d87bc453349 58 /***********************************/
ninoderkinderen 0:8d87bc453349 59 /*
ninoderkinderen 0:8d87bc453349 60 * Initialize the random number generator.
ninoderkinderen 0:8d87bc453349 61 *
ninoderkinderen 0:8d87bc453349 62 * Since this is to be called on power up, we don't have much
ninoderkinderen 0:8d87bc453349 63 * system randomess to work with. Here all we use is the
ninoderkinderen 0:8d87bc453349 64 * real-time clock. We'll accumulate more randomness as soon
ninoderkinderen 0:8d87bc453349 65 * as things start happening.
ninoderkinderen 0:8d87bc453349 66 */
ninoderkinderen 0:8d87bc453349 67 void
ninoderkinderen 0:8d87bc453349 68 avRandomInit()
ninoderkinderen 0:8d87bc453349 69 {
ninoderkinderen 0:8d87bc453349 70 avChurnRand(NULL, 0);
ninoderkinderen 0:8d87bc453349 71 }
ninoderkinderen 0:8d87bc453349 72
ninoderkinderen 0:8d87bc453349 73 /*
ninoderkinderen 0:8d87bc453349 74 * Churn the randomness pool on a random event. Call this early and often
ninoderkinderen 0:8d87bc453349 75 * on random and semi-random system events to build randomness in time for
ninoderkinderen 0:8d87bc453349 76 * usage. For randomly timed events, pass a null pointer and a zero length
ninoderkinderen 0:8d87bc453349 77 * and this will use the system timer and other sources to add randomness.
ninoderkinderen 0:8d87bc453349 78 * If new random data is available, pass a pointer to that and it will be
ninoderkinderen 0:8d87bc453349 79 * included.
ninoderkinderen 0:8d87bc453349 80 *
ninoderkinderen 0:8d87bc453349 81 * Ref: Applied Cryptography 2nd Ed. by Bruce Schneier p. 427
ninoderkinderen 0:8d87bc453349 82 */
ninoderkinderen 0:8d87bc453349 83 void
ninoderkinderen 0:8d87bc453349 84 avChurnRand(char *randData, u32_t randLen)
ninoderkinderen 0:8d87bc453349 85 {
ninoderkinderen 0:8d87bc453349 86 MD5_CTX md5;
ninoderkinderen 0:8d87bc453349 87
ninoderkinderen 0:8d87bc453349 88 /* LWIP_DEBUGF(LOG_INFO, ("churnRand: %u@%P\n", randLen, randData)); */
ninoderkinderen 0:8d87bc453349 89 MD5Init(&md5);
ninoderkinderen 0:8d87bc453349 90 MD5Update(&md5, (u_char *)randPool, sizeof(randPool));
ninoderkinderen 0:8d87bc453349 91 if (randData) {
ninoderkinderen 0:8d87bc453349 92 MD5Update(&md5, (u_char *)randData, randLen);
ninoderkinderen 0:8d87bc453349 93 } else {
ninoderkinderen 0:8d87bc453349 94 struct {
ninoderkinderen 0:8d87bc453349 95 /* INCLUDE fields for any system sources of randomness */
ninoderkinderen 0:8d87bc453349 96 char foobar;
ninoderkinderen 0:8d87bc453349 97 } sysData;
ninoderkinderen 0:8d87bc453349 98
ninoderkinderen 0:8d87bc453349 99 /* Load sysData fields here. */
ninoderkinderen 0:8d87bc453349 100 MD5Update(&md5, (u_char *)&sysData, sizeof(sysData));
ninoderkinderen 0:8d87bc453349 101 }
ninoderkinderen 0:8d87bc453349 102 MD5Final((u_char *)randPool, &md5);
ninoderkinderen 0:8d87bc453349 103 /* LWIP_DEBUGF(LOG_INFO, ("churnRand: -> 0\n")); */
ninoderkinderen 0:8d87bc453349 104 }
ninoderkinderen 0:8d87bc453349 105
ninoderkinderen 0:8d87bc453349 106 /*
ninoderkinderen 0:8d87bc453349 107 * Use the random pool to generate random data. This degrades to pseudo
ninoderkinderen 0:8d87bc453349 108 * random when used faster than randomness is supplied using churnRand().
ninoderkinderen 0:8d87bc453349 109 * Note: It's important that there be sufficient randomness in randPool
ninoderkinderen 0:8d87bc453349 110 * before this is called for otherwise the range of the result may be
ninoderkinderen 0:8d87bc453349 111 * narrow enough to make a search feasible.
ninoderkinderen 0:8d87bc453349 112 *
ninoderkinderen 0:8d87bc453349 113 * Ref: Applied Cryptography 2nd Ed. by Bruce Schneier p. 427
ninoderkinderen 0:8d87bc453349 114 *
ninoderkinderen 0:8d87bc453349 115 * XXX Why does he not just call churnRand() for each block? Probably
ninoderkinderen 0:8d87bc453349 116 * so that you don't ever publish the seed which could possibly help
ninoderkinderen 0:8d87bc453349 117 * predict future values.
ninoderkinderen 0:8d87bc453349 118 * XXX Why don't we preserve md5 between blocks and just update it with
ninoderkinderen 0:8d87bc453349 119 * randCount each time? Probably there is a weakness but I wish that
ninoderkinderen 0:8d87bc453349 120 * it was documented.
ninoderkinderen 0:8d87bc453349 121 */
ninoderkinderen 0:8d87bc453349 122 void
ninoderkinderen 0:8d87bc453349 123 avGenRand(char *buf, u32_t bufLen)
ninoderkinderen 0:8d87bc453349 124 {
ninoderkinderen 0:8d87bc453349 125 MD5_CTX md5;
ninoderkinderen 0:8d87bc453349 126 u_char tmp[16];
ninoderkinderen 0:8d87bc453349 127 u32_t n;
ninoderkinderen 0:8d87bc453349 128
ninoderkinderen 0:8d87bc453349 129 while (bufLen > 0) {
ninoderkinderen 0:8d87bc453349 130 n = LWIP_MIN(bufLen, RANDPOOLSZ);
ninoderkinderen 0:8d87bc453349 131 MD5Init(&md5);
ninoderkinderen 0:8d87bc453349 132 MD5Update(&md5, (u_char *)randPool, sizeof(randPool));
ninoderkinderen 0:8d87bc453349 133 MD5Update(&md5, (u_char *)&randCount, sizeof(randCount));
ninoderkinderen 0:8d87bc453349 134 MD5Final(tmp, &md5);
ninoderkinderen 0:8d87bc453349 135 randCount++;
ninoderkinderen 0:8d87bc453349 136 MEMCPY(buf, tmp, n);
ninoderkinderen 0:8d87bc453349 137 buf += n;
ninoderkinderen 0:8d87bc453349 138 bufLen -= n;
ninoderkinderen 0:8d87bc453349 139 }
ninoderkinderen 0:8d87bc453349 140 }
ninoderkinderen 0:8d87bc453349 141
ninoderkinderen 0:8d87bc453349 142 /*
ninoderkinderen 0:8d87bc453349 143 * Return a new random number.
ninoderkinderen 0:8d87bc453349 144 */
ninoderkinderen 0:8d87bc453349 145 u32_t
ninoderkinderen 0:8d87bc453349 146 avRandom()
ninoderkinderen 0:8d87bc453349 147 {
ninoderkinderen 0:8d87bc453349 148 u32_t newRand;
ninoderkinderen 0:8d87bc453349 149
ninoderkinderen 0:8d87bc453349 150 avGenRand((char *)&newRand, sizeof(newRand));
ninoderkinderen 0:8d87bc453349 151
ninoderkinderen 0:8d87bc453349 152 return newRand;
ninoderkinderen 0:8d87bc453349 153 }
ninoderkinderen 0:8d87bc453349 154
ninoderkinderen 0:8d87bc453349 155 #else /* MD5_SUPPORT */
ninoderkinderen 0:8d87bc453349 156
ninoderkinderen 0:8d87bc453349 157 /*****************************/
ninoderkinderen 0:8d87bc453349 158 /*** LOCAL DATA STRUCTURES ***/
ninoderkinderen 0:8d87bc453349 159 /*****************************/
ninoderkinderen 0:8d87bc453349 160 static int avRandomized = 0; /* Set when truely randomized. */
ninoderkinderen 0:8d87bc453349 161 static u32_t avRandomSeed = 0; /* Seed used for random number generation. */
ninoderkinderen 0:8d87bc453349 162
ninoderkinderen 0:8d87bc453349 163
ninoderkinderen 0:8d87bc453349 164 /***********************************/
ninoderkinderen 0:8d87bc453349 165 /*** PUBLIC FUNCTION DEFINITIONS ***/
ninoderkinderen 0:8d87bc453349 166 /***********************************/
ninoderkinderen 0:8d87bc453349 167 /*
ninoderkinderen 0:8d87bc453349 168 * Initialize the random number generator.
ninoderkinderen 0:8d87bc453349 169 *
ninoderkinderen 0:8d87bc453349 170 * Here we attempt to compute a random number seed but even if
ninoderkinderen 0:8d87bc453349 171 * it isn't random, we'll randomize it later.
ninoderkinderen 0:8d87bc453349 172 *
ninoderkinderen 0:8d87bc453349 173 * The current method uses the fields from the real time clock,
ninoderkinderen 0:8d87bc453349 174 * the idle process counter, the millisecond counter, and the
ninoderkinderen 0:8d87bc453349 175 * hardware timer tick counter. When this is invoked
ninoderkinderen 0:8d87bc453349 176 * in startup(), then the idle counter and timer values may
ninoderkinderen 0:8d87bc453349 177 * repeat after each boot and the real time clock may not be
ninoderkinderen 0:8d87bc453349 178 * operational. Thus we call it again on the first random
ninoderkinderen 0:8d87bc453349 179 * event.
ninoderkinderen 0:8d87bc453349 180 */
ninoderkinderen 0:8d87bc453349 181 void
ninoderkinderen 0:8d87bc453349 182 avRandomInit()
ninoderkinderen 0:8d87bc453349 183 {
ninoderkinderen 0:8d87bc453349 184 #if 0
ninoderkinderen 0:8d87bc453349 185 /* Get a pointer into the last 4 bytes of clockBuf. */
ninoderkinderen 0:8d87bc453349 186 u32_t *lptr1 = (u32_t *)((char *)&clockBuf[3]);
ninoderkinderen 0:8d87bc453349 187
ninoderkinderen 0:8d87bc453349 188 /*
ninoderkinderen 0:8d87bc453349 189 * Initialize our seed using the real-time clock, the idle
ninoderkinderen 0:8d87bc453349 190 * counter, the millisecond timer, and the hardware timer
ninoderkinderen 0:8d87bc453349 191 * tick counter. The real-time clock and the hardware
ninoderkinderen 0:8d87bc453349 192 * tick counter are the best sources of randomness but
ninoderkinderen 0:8d87bc453349 193 * since the tick counter is only 16 bit (and truncated
ninoderkinderen 0:8d87bc453349 194 * at that), the idle counter and millisecond timer
ninoderkinderen 0:8d87bc453349 195 * (which may be small values) are added to help
ninoderkinderen 0:8d87bc453349 196 * randomize the lower 16 bits of the seed.
ninoderkinderen 0:8d87bc453349 197 */
ninoderkinderen 0:8d87bc453349 198 readClk();
ninoderkinderen 0:8d87bc453349 199 avRandomSeed += *(u32_t *)clockBuf + *lptr1 + OSIdleCtr
ninoderkinderen 0:8d87bc453349 200 + ppp_mtime() + ((u32_t)TM1 << 16) + TM1;
ninoderkinderen 0:8d87bc453349 201 #else
ninoderkinderen 0:8d87bc453349 202 avRandomSeed += sys_jiffies(); /* XXX */
ninoderkinderen 0:8d87bc453349 203 #endif
ninoderkinderen 0:8d87bc453349 204
ninoderkinderen 0:8d87bc453349 205 /* Initialize the Borland random number generator. */
ninoderkinderen 0:8d87bc453349 206 srand((unsigned)avRandomSeed);
ninoderkinderen 0:8d87bc453349 207 }
ninoderkinderen 0:8d87bc453349 208
ninoderkinderen 0:8d87bc453349 209 /*
ninoderkinderen 0:8d87bc453349 210 * Randomize our random seed value. Here we use the fact that
ninoderkinderen 0:8d87bc453349 211 * this function is called at *truely random* times by the polling
ninoderkinderen 0:8d87bc453349 212 * and network functions. Here we only get 16 bits of new random
ninoderkinderen 0:8d87bc453349 213 * value but we use the previous value to randomize the other 16
ninoderkinderen 0:8d87bc453349 214 * bits.
ninoderkinderen 0:8d87bc453349 215 */
ninoderkinderen 0:8d87bc453349 216 void
ninoderkinderen 0:8d87bc453349 217 avRandomize(void)
ninoderkinderen 0:8d87bc453349 218 {
ninoderkinderen 0:8d87bc453349 219 static u32_t last_jiffies;
ninoderkinderen 0:8d87bc453349 220
ninoderkinderen 0:8d87bc453349 221 if (!avRandomized) {
ninoderkinderen 0:8d87bc453349 222 avRandomized = !0;
ninoderkinderen 0:8d87bc453349 223 avRandomInit();
ninoderkinderen 0:8d87bc453349 224 /* The initialization function also updates the seed. */
ninoderkinderen 0:8d87bc453349 225 } else {
ninoderkinderen 0:8d87bc453349 226 /* avRandomSeed += (avRandomSeed << 16) + TM1; */
ninoderkinderen 0:8d87bc453349 227 avRandomSeed += (sys_jiffies() - last_jiffies); /* XXX */
ninoderkinderen 0:8d87bc453349 228 }
ninoderkinderen 0:8d87bc453349 229 last_jiffies = sys_jiffies();
ninoderkinderen 0:8d87bc453349 230 }
ninoderkinderen 0:8d87bc453349 231
ninoderkinderen 0:8d87bc453349 232 /*
ninoderkinderen 0:8d87bc453349 233 * Return a new random number.
ninoderkinderen 0:8d87bc453349 234 * Here we use the Borland rand() function to supply a pseudo random
ninoderkinderen 0:8d87bc453349 235 * number which we make truely random by combining it with our own
ninoderkinderen 0:8d87bc453349 236 * seed which is randomized by truely random events.
ninoderkinderen 0:8d87bc453349 237 * Thus the numbers will be truely random unless there have been no
ninoderkinderen 0:8d87bc453349 238 * operator or network events in which case it will be pseudo random
ninoderkinderen 0:8d87bc453349 239 * seeded by the real time clock.
ninoderkinderen 0:8d87bc453349 240 */
ninoderkinderen 0:8d87bc453349 241 u32_t
ninoderkinderen 0:8d87bc453349 242 avRandom()
ninoderkinderen 0:8d87bc453349 243 {
ninoderkinderen 0:8d87bc453349 244 return ((((u32_t)rand() << 16) + rand()) + avRandomSeed);
ninoderkinderen 0:8d87bc453349 245 }
ninoderkinderen 0:8d87bc453349 246
ninoderkinderen 0:8d87bc453349 247 #endif /* MD5_SUPPORT */
ninoderkinderen 0:8d87bc453349 248
ninoderkinderen 0:8d87bc453349 249 #endif /* PPP_SUPPORT */