90 lines
1.9 KiB
C
90 lines
1.9 KiB
C
/*
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This file is part of libcapwap.
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libcapwap is free software: you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation, either version 3 of the License, or
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(at your option) any later version.
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libcapwap is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with Foobar. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include <stdlib.h>
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#include <stdint.h>
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#include <stdio.h>
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#include <string.h>
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#include <errno.h>
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#include <unistd.h>
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#include <time.h>
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#include <sys/types.h>
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#include <sys/stat.h>
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#include <fcntl.h>
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#include "rand.h"
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#include "log.h"
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char *cw_rand_dev = "/dev/random";
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int cw_rand_r(uint8_t * dst, int len)
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{
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int rf;
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int l;
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rf = open(cw_rand_dev, O_RDONLY | O_NONBLOCK);
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if (rf < 0) {
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cw_log(LOG_ERR, "Can't open %s: %s", cw_rand_dev, strerror(errno));
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return 0;
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}
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l = read(rf, dst, len);
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close(rf);
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if ((l < 0) && (errno != EAGAIN)) {
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cw_log(LOG_ERR, "Cant read from %s: %s", cw_rand_dev, strerror(errno));
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return 0;
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}
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return l;
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}
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/**
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* Generate random bytes
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* @param dst Destination where to store random bytes
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* @param len Number of bytes to generate
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* @return Number of generated bytes
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*/
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int cw_rand(uint8_t * dst, int len)
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{
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static uint32_t rinit = 0;
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int i;
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if (!rinit) {
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int l = cw_rand_r((uint8_t *) (&rinit), sizeof(uint32_t));
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if (l < sizeof(uint32_t)) {
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cw_log(LOG_WARNING,
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"Can't read enough bytes from %s. Using time to init rand instead.",
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cw_rand_dev);
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rinit = time(NULL);
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}
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srand(rinit);
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}
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for (i = 0; i < len; i++) {
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dst[i] = rand();
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}
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return len;
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}
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