esp-idf/components/lwip/netif/ppp/pppcrypt.c

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2016-08-17 11:08:22 -04:00
/*
* pppcrypt.c - PPP/DES linkage for MS-CHAP and EAP SRP-SHA1
*
* Extracted from chap_ms.c by James Carlson.
*
* Copyright (c) 1995 Eric Rosenquist. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
*
* 3. The name(s) of the authors of this software must not be used to
* endorse or promote products derived from this software without
* prior written permission.
*
* THE AUTHORS OF THIS SOFTWARE DISCLAIM ALL WARRANTIES WITH REGARD TO
* THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
* AND FITNESS, IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY
* SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN
* AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING
* OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
#include "lwip/opt.h"
#if PPP_SUPPORT && MSCHAP_SUPPORT /* don't build if not necessary */
#include "netif/ppp/ppp_impl.h"
#include "netif/ppp/pppcrypt.h"
static u_char pppcrypt_get_7bits(u_char *input, int startBit) {
unsigned int word;
word = (unsigned)input[startBit / 8] << 8;
word |= (unsigned)input[startBit / 8 + 1];
word >>= 15 - (startBit % 8 + 7);
return word & 0xFE;
}
/* IN 56 bit DES key missing parity bits
* OUT 64 bit DES key with parity bits added
*/
void pppcrypt_56_to_64_bit_key(u_char *key, u_char * des_key) {
des_key[0] = pppcrypt_get_7bits(key, 0);
des_key[1] = pppcrypt_get_7bits(key, 7);
des_key[2] = pppcrypt_get_7bits(key, 14);
des_key[3] = pppcrypt_get_7bits(key, 21);
des_key[4] = pppcrypt_get_7bits(key, 28);
des_key[5] = pppcrypt_get_7bits(key, 35);
des_key[6] = pppcrypt_get_7bits(key, 42);
des_key[7] = pppcrypt_get_7bits(key, 49);
}
#endif /* PPP_SUPPORT && MSCHAP_SUPPORT */