717425320f
kernel: stop gathering timestamps once the bin is full per interrupt random: once seeded, retrieve new entropy at a lower rate Change-Id: I4ce6081d39274728d82c6889686d1650cfd5fc2e
35 lines
1 KiB
C
35 lines
1 KiB
C
#include <lib.h>
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#include <stdlib.h>
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#include <string.h>
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#include <minix/profile.h>
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#include <minix/syslib.h>
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#include <minix/type.h>
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#include <minix/minlib.h>
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#include <minix/sysutil.h>
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/*===========================================================================*
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* get_randomness *
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*===========================================================================*/
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void get_randomness(rand, source)
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struct k_randomness *rand;
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int source;
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{
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/* Use architecture-dependent high-resolution clock for
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* raw entropy gathering.
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*/
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int r_next;
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unsigned long tsc_high, tsc_low;
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source %= RANDOM_SOURCES;
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if (rand->bin[source].r_size >= RANDOM_ELEMENTS) return;
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r_next= rand->bin[source].r_next;
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read_tsc((u32_t *) &tsc_high, (u32_t *) &tsc_low);
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rand->bin[source].r_buf[r_next] = tsc_low;
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if (rand->bin[source].r_size < RANDOM_ELEMENTS) {
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rand->bin[source].r_size ++;
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}
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rand->bin[source].r_next = (r_next + 1 ) % RANDOM_ELEMENTS;
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}
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