NetServicesSource - Experimental HTTPClient with proxy support

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Experimental HTTPClient with proxy support

lwip/netif/ppp/randm.c@0:b56b6a05cad4, 2011-06-29 (annotated)

Committer:: igorsk
Date:: Wed Jun 29 16:01:58 2011 +0000
Revision:: 0:b56b6a05cad4

Who changed what in which revision?

User	Revision	Line number	New contents of line
igorsk	0:b56b6a05cad4	1	/*****************************************************************************
igorsk	0:b56b6a05cad4	2	* randm.c - Random number generator program file.
igorsk	0:b56b6a05cad4	3	*
igorsk	0:b56b6a05cad4	4	* Copyright (c) 2003 by Marc Boucher, Services Informatiques (MBSI) inc.
igorsk	0:b56b6a05cad4	5	* Copyright (c) 1998 by Global Election Systems Inc.
igorsk	0:b56b6a05cad4	6	*
igorsk	0:b56b6a05cad4	7	* The authors hereby grant permission to use, copy, modify, distribute,
igorsk	0:b56b6a05cad4	8	* and license this software and its documentation for any purpose, provided
igorsk	0:b56b6a05cad4	9	* that existing copyright notices are retained in all copies and that this
igorsk	0:b56b6a05cad4	10	* notice and the following disclaimer are included verbatim in any
igorsk	0:b56b6a05cad4	11	* distributions. No written agreement, license, or royalty fee is required
igorsk	0:b56b6a05cad4	12	* for any of the authorized uses.
igorsk	0:b56b6a05cad4	13	*
igorsk	0:b56b6a05cad4	14	* THIS SOFTWARE IS PROVIDED BY THE CONTRIBUTORS AS IS AND ANY EXPRESS OR
igorsk	0:b56b6a05cad4	15	* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
igorsk	0:b56b6a05cad4	16	* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
igorsk	0:b56b6a05cad4	17	* IN NO EVENT SHALL THE CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
igorsk	0:b56b6a05cad4	18	* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
igorsk	0:b56b6a05cad4	19	* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
igorsk	0:b56b6a05cad4	20	* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
igorsk	0:b56b6a05cad4	21	* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
igorsk	0:b56b6a05cad4	22	* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
igorsk	0:b56b6a05cad4	23	* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
igorsk	0:b56b6a05cad4	24	*
igorsk	0:b56b6a05cad4	25	******************************************************************************
igorsk	0:b56b6a05cad4	26	* REVISION HISTORY
igorsk	0:b56b6a05cad4	27	*
igorsk	0:b56b6a05cad4	28	* 03-01-01 Marc Boucher <marc@mbsi.ca>
igorsk	0:b56b6a05cad4	29	* Ported to lwIP.
igorsk	0:b56b6a05cad4	30	* 98-06-03 Guy Lancaster <lancasterg@acm.org>, Global Election Systems Inc.
igorsk	0:b56b6a05cad4	31	* Extracted from avos.
igorsk	0:b56b6a05cad4	32	*****************************************************************************/
igorsk	0:b56b6a05cad4	33
igorsk	0:b56b6a05cad4	34	#include "lwip/opt.h"
igorsk	0:b56b6a05cad4	35
igorsk	0:b56b6a05cad4	36	#if PPP_SUPPORT /* don't build if not configured for use in lwipopts.h */
igorsk	0:b56b6a05cad4	37
igorsk	0:b56b6a05cad4	38	#include "md5.h"
igorsk	0:b56b6a05cad4	39	#include "randm.h"
igorsk	0:b56b6a05cad4	40
igorsk	0:b56b6a05cad4	41	#include "ppp.h"
igorsk	0:b56b6a05cad4	42	#include "pppdebug.h"
igorsk	0:b56b6a05cad4	43
igorsk	0:b56b6a05cad4	44	#include <string.h>
igorsk	0:b56b6a05cad4	45
igorsk	0:b56b6a05cad4	46	#if MD5_SUPPORT /* this module depends on MD5 */
igorsk	0:b56b6a05cad4	47	#define RANDPOOLSZ 16 /* Bytes stored in the pool of randomness. */
igorsk	0:b56b6a05cad4	48
igorsk	0:b56b6a05cad4	49	/*****************************/
igorsk	0:b56b6a05cad4	50	/* LOCAL DATA STRUCTURES */
igorsk	0:b56b6a05cad4	51	/*****************************/
igorsk	0:b56b6a05cad4	52	static char randPool[RANDPOOLSZ]; /* Pool of randomness. */
igorsk	0:b56b6a05cad4	53	static long randCount = 0; /* Pseudo-random incrementer */
igorsk	0:b56b6a05cad4	54
igorsk	0:b56b6a05cad4	55
igorsk	0:b56b6a05cad4	56	/***********************************/
igorsk	0:b56b6a05cad4	57	/* PUBLIC FUNCTION DEFINITIONS */
igorsk	0:b56b6a05cad4	58	/***********************************/
igorsk	0:b56b6a05cad4	59	/*
igorsk	0:b56b6a05cad4	60	* Initialize the random number generator.
igorsk	0:b56b6a05cad4	61	*
igorsk	0:b56b6a05cad4	62	* Since this is to be called on power up, we don't have much
igorsk	0:b56b6a05cad4	63	* system randomess to work with. Here all we use is the
igorsk	0:b56b6a05cad4	64	* real-time clock. We'll accumulate more randomness as soon
igorsk	0:b56b6a05cad4	65	* as things start happening.
igorsk	0:b56b6a05cad4	66	*/
igorsk	0:b56b6a05cad4	67	void
igorsk	0:b56b6a05cad4	68	avRandomInit()
igorsk	0:b56b6a05cad4	69	{
igorsk	0:b56b6a05cad4	70	avChurnRand(NULL, 0);
igorsk	0:b56b6a05cad4	71	}
igorsk	0:b56b6a05cad4	72
igorsk	0:b56b6a05cad4	73	/*
igorsk	0:b56b6a05cad4	74	* Churn the randomness pool on a random event. Call this early and often
igorsk	0:b56b6a05cad4	75	* on random and semi-random system events to build randomness in time for
igorsk	0:b56b6a05cad4	76	* usage. For randomly timed events, pass a null pointer and a zero length
igorsk	0:b56b6a05cad4	77	* and this will use the system timer and other sources to add randomness.
igorsk	0:b56b6a05cad4	78	* If new random data is available, pass a pointer to that and it will be
igorsk	0:b56b6a05cad4	79	* included.
igorsk	0:b56b6a05cad4	80	*
igorsk	0:b56b6a05cad4	81	* Ref: Applied Cryptography 2nd Ed. by Bruce Schneier p. 427
igorsk	0:b56b6a05cad4	82	*/
igorsk	0:b56b6a05cad4	83	void
igorsk	0:b56b6a05cad4	84	avChurnRand(char *randData, u32_t randLen)
igorsk	0:b56b6a05cad4	85	{
igorsk	0:b56b6a05cad4	86	MD5_CTX md5;
igorsk	0:b56b6a05cad4	87
igorsk	0:b56b6a05cad4	88	/* LWIP_DEBUGF(LOG_INFO, ("churnRand: %u@%P\n", randLen, randData)); */
igorsk	0:b56b6a05cad4	89	MD5Init(&md5);
igorsk	0:b56b6a05cad4	90	MD5Update(&md5, (u_char *)randPool, sizeof(randPool));
igorsk	0:b56b6a05cad4	91	if (randData) {
igorsk	0:b56b6a05cad4	92	MD5Update(&md5, (u_char *)randData, randLen);
igorsk	0:b56b6a05cad4	93	} else {
igorsk	0:b56b6a05cad4	94	struct {
igorsk	0:b56b6a05cad4	95	/* INCLUDE fields for any system sources of randomness */
igorsk	0:b56b6a05cad4	96	char foobar;
igorsk	0:b56b6a05cad4	97	} sysData;
igorsk	0:b56b6a05cad4	98
igorsk	0:b56b6a05cad4	99	/* Load sysData fields here. */
igorsk	0:b56b6a05cad4	100	MD5Update(&md5, (u_char *)&sysData, sizeof(sysData));
igorsk	0:b56b6a05cad4	101	}
igorsk	0:b56b6a05cad4	102	MD5Final((u_char *)randPool, &md5);
igorsk	0:b56b6a05cad4	103	/* LWIP_DEBUGF(LOG_INFO, ("churnRand: -> 0\n")); */
igorsk	0:b56b6a05cad4	104	}
igorsk	0:b56b6a05cad4	105
igorsk	0:b56b6a05cad4	106	/*
igorsk	0:b56b6a05cad4	107	* Use the random pool to generate random data. This degrades to pseudo
igorsk	0:b56b6a05cad4	108	* random when used faster than randomness is supplied using churnRand().
igorsk	0:b56b6a05cad4	109	* Note: It's important that there be sufficient randomness in randPool
igorsk	0:b56b6a05cad4	110	* before this is called for otherwise the range of the result may be
igorsk	0:b56b6a05cad4	111	* narrow enough to make a search feasible.
igorsk	0:b56b6a05cad4	112	*
igorsk	0:b56b6a05cad4	113	* Ref: Applied Cryptography 2nd Ed. by Bruce Schneier p. 427
igorsk	0:b56b6a05cad4	114	*
igorsk	0:b56b6a05cad4	115	* XXX Why does he not just call churnRand() for each block? Probably
igorsk	0:b56b6a05cad4	116	* so that you don't ever publish the seed which could possibly help
igorsk	0:b56b6a05cad4	117	* predict future values.
igorsk	0:b56b6a05cad4	118	* XXX Why don't we preserve md5 between blocks and just update it with
igorsk	0:b56b6a05cad4	119	* randCount each time? Probably there is a weakness but I wish that
igorsk	0:b56b6a05cad4	120	* it was documented.
igorsk	0:b56b6a05cad4	121	*/
igorsk	0:b56b6a05cad4	122	void
igorsk	0:b56b6a05cad4	123	avGenRand(char *buf, u32_t bufLen)
igorsk	0:b56b6a05cad4	124	{
igorsk	0:b56b6a05cad4	125	MD5_CTX md5;
igorsk	0:b56b6a05cad4	126	u_char tmp[16];
igorsk	0:b56b6a05cad4	127	u32_t n;
igorsk	0:b56b6a05cad4	128
igorsk	0:b56b6a05cad4	129	while (bufLen > 0) {
igorsk	0:b56b6a05cad4	130	n = LWIP_MIN(bufLen, RANDPOOLSZ);
igorsk	0:b56b6a05cad4	131	MD5Init(&md5);
igorsk	0:b56b6a05cad4	132	MD5Update(&md5, (u_char *)randPool, sizeof(randPool));
igorsk	0:b56b6a05cad4	133	MD5Update(&md5, (u_char *)&randCount, sizeof(randCount));
igorsk	0:b56b6a05cad4	134	MD5Final(tmp, &md5);
igorsk	0:b56b6a05cad4	135	randCount++;
igorsk	0:b56b6a05cad4	136	MEMCPY(buf, tmp, n);
igorsk	0:b56b6a05cad4	137	buf += n;
igorsk	0:b56b6a05cad4	138	bufLen -= n;
igorsk	0:b56b6a05cad4	139	}
igorsk	0:b56b6a05cad4	140	}
igorsk	0:b56b6a05cad4	141
igorsk	0:b56b6a05cad4	142	/*
igorsk	0:b56b6a05cad4	143	* Return a new random number.
igorsk	0:b56b6a05cad4	144	*/
igorsk	0:b56b6a05cad4	145	u32_t
igorsk	0:b56b6a05cad4	146	avRandom()
igorsk	0:b56b6a05cad4	147	{
igorsk	0:b56b6a05cad4	148	u32_t newRand;
igorsk	0:b56b6a05cad4	149
igorsk	0:b56b6a05cad4	150	avGenRand((char *)&newRand, sizeof(newRand));
igorsk	0:b56b6a05cad4	151
igorsk	0:b56b6a05cad4	152	return newRand;
igorsk	0:b56b6a05cad4	153	}
igorsk	0:b56b6a05cad4	154
igorsk	0:b56b6a05cad4	155	#else /* MD5_SUPPORT */
igorsk	0:b56b6a05cad4	156
igorsk	0:b56b6a05cad4	157	/*****************************/
igorsk	0:b56b6a05cad4	158	/* LOCAL DATA STRUCTURES */
igorsk	0:b56b6a05cad4	159	/*****************************/
igorsk	0:b56b6a05cad4	160	static int avRandomized = 0; /* Set when truely randomized. */
igorsk	0:b56b6a05cad4	161	static u32_t avRandomSeed = 0; /* Seed used for random number generation. */
igorsk	0:b56b6a05cad4	162
igorsk	0:b56b6a05cad4	163
igorsk	0:b56b6a05cad4	164	/***********************************/
igorsk	0:b56b6a05cad4	165	/* PUBLIC FUNCTION DEFINITIONS */
igorsk	0:b56b6a05cad4	166	/***********************************/
igorsk	0:b56b6a05cad4	167	/*
igorsk	0:b56b6a05cad4	168	* Initialize the random number generator.
igorsk	0:b56b6a05cad4	169	*
igorsk	0:b56b6a05cad4	170	* Here we attempt to compute a random number seed but even if
igorsk	0:b56b6a05cad4	171	* it isn't random, we'll randomize it later.
igorsk	0:b56b6a05cad4	172	*
igorsk	0:b56b6a05cad4	173	* The current method uses the fields from the real time clock,
igorsk	0:b56b6a05cad4	174	* the idle process counter, the millisecond counter, and the
igorsk	0:b56b6a05cad4	175	* hardware timer tick counter. When this is invoked
igorsk	0:b56b6a05cad4	176	* in startup(), then the idle counter and timer values may
igorsk	0:b56b6a05cad4	177	* repeat after each boot and the real time clock may not be
igorsk	0:b56b6a05cad4	178	* operational. Thus we call it again on the first random
igorsk	0:b56b6a05cad4	179	* event.
igorsk	0:b56b6a05cad4	180	*/
igorsk	0:b56b6a05cad4	181	void
igorsk	0:b56b6a05cad4	182	avRandomInit()
igorsk	0:b56b6a05cad4	183	{
igorsk	0:b56b6a05cad4	184	#if 0
igorsk	0:b56b6a05cad4	185	/* Get a pointer into the last 4 bytes of clockBuf. */
igorsk	0:b56b6a05cad4	186	u32_t lptr1 = (u32_t )((char *)&clockBuf[3]);
igorsk	0:b56b6a05cad4	187
igorsk	0:b56b6a05cad4	188	/*
igorsk	0:b56b6a05cad4	189	* Initialize our seed using the real-time clock, the idle
igorsk	0:b56b6a05cad4	190	* counter, the millisecond timer, and the hardware timer
igorsk	0:b56b6a05cad4	191	* tick counter. The real-time clock and the hardware
igorsk	0:b56b6a05cad4	192	* tick counter are the best sources of randomness but
igorsk	0:b56b6a05cad4	193	* since the tick counter is only 16 bit (and truncated
igorsk	0:b56b6a05cad4	194	* at that), the idle counter and millisecond timer
igorsk	0:b56b6a05cad4	195	* (which may be small values) are added to help
igorsk	0:b56b6a05cad4	196	* randomize the lower 16 bits of the seed.
igorsk	0:b56b6a05cad4	197	*/
igorsk	0:b56b6a05cad4	198	readClk();
igorsk	0:b56b6a05cad4	199	avRandomSeed += (u32_t )clockBuf + *lptr1 + OSIdleCtr
igorsk	0:b56b6a05cad4	200	+ ppp_mtime() + ((u32_t)TM1 << 16) + TM1;
igorsk	0:b56b6a05cad4	201	#else
igorsk	0:b56b6a05cad4	202	avRandomSeed += sys_jiffies(); /* XXX */
igorsk	0:b56b6a05cad4	203	#endif
igorsk	0:b56b6a05cad4	204
igorsk	0:b56b6a05cad4	205	/* Initialize the Borland random number generator. */
igorsk	0:b56b6a05cad4	206	srand((unsigned)avRandomSeed);
igorsk	0:b56b6a05cad4	207	}
igorsk	0:b56b6a05cad4	208
igorsk	0:b56b6a05cad4	209	/*
igorsk	0:b56b6a05cad4	210	* Randomize our random seed value. Here we use the fact that
igorsk	0:b56b6a05cad4	211	* this function is called at truely random times by the polling
igorsk	0:b56b6a05cad4	212	* and network functions. Here we only get 16 bits of new random
igorsk	0:b56b6a05cad4	213	* value but we use the previous value to randomize the other 16
igorsk	0:b56b6a05cad4	214	* bits.
igorsk	0:b56b6a05cad4	215	*/
igorsk	0:b56b6a05cad4	216	void
igorsk	0:b56b6a05cad4	217	avRandomize(void)
igorsk	0:b56b6a05cad4	218	{
igorsk	0:b56b6a05cad4	219	static u32_t last_jiffies;
igorsk	0:b56b6a05cad4	220
igorsk	0:b56b6a05cad4	221	if (!avRandomized) {
igorsk	0:b56b6a05cad4	222	avRandomized = !0;
igorsk	0:b56b6a05cad4	223	avRandomInit();
igorsk	0:b56b6a05cad4	224	/* The initialization function also updates the seed. */
igorsk	0:b56b6a05cad4	225	} else {
igorsk	0:b56b6a05cad4	226	/* avRandomSeed += (avRandomSeed << 16) + TM1; */
igorsk	0:b56b6a05cad4	227	avRandomSeed += (sys_jiffies() - last_jiffies); /* XXX */
igorsk	0:b56b6a05cad4	228	}
igorsk	0:b56b6a05cad4	229	last_jiffies = sys_jiffies();
igorsk	0:b56b6a05cad4	230	}
igorsk	0:b56b6a05cad4	231
igorsk	0:b56b6a05cad4	232	/*
igorsk	0:b56b6a05cad4	233	* Return a new random number.
igorsk	0:b56b6a05cad4	234	* Here we use the Borland rand() function to supply a pseudo random
igorsk	0:b56b6a05cad4	235	* number which we make truely random by combining it with our own
igorsk	0:b56b6a05cad4	236	* seed which is randomized by truely random events.
igorsk	0:b56b6a05cad4	237	* Thus the numbers will be truely random unless there have been no
igorsk	0:b56b6a05cad4	238	* operator or network events in which case it will be pseudo random
igorsk	0:b56b6a05cad4	239	* seeded by the real time clock.
igorsk	0:b56b6a05cad4	240	*/
igorsk	0:b56b6a05cad4	241	u32_t
igorsk	0:b56b6a05cad4	242	avRandom()
igorsk	0:b56b6a05cad4	243	{
igorsk	0:b56b6a05cad4	244	return ((((u32_t)rand() << 16) + rand()) + avRandomSeed);
igorsk	0:b56b6a05cad4	245	}
igorsk	0:b56b6a05cad4	246
igorsk	0:b56b6a05cad4	247	#endif /* MD5_SUPPORT */
igorsk	0:b56b6a05cad4	248
igorsk	0:b56b6a05cad4	249	#endif /* PPP_SUPPORT */

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Type:	Program
Created:	29 Jun 2011
Imports:	167
Forks:	0
Commits:	1
Dependents:	0
Dependencies:	0
Followers:	3

lwip/netif/ppp/randm.c@0:b56b6a05cad4, 2011-06-29 (annotated)

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