mirror of
https://github.com/didyouexpectthat/zerotierone.git
synced 2024-09-19 04:10:20 -07:00
121 lines
2.4 KiB
C++
121 lines
2.4 KiB
C++
/*
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* Based on public domain code available at: http://cr.yp.to/snuffle.html
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*
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* This therefore is public domain.
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*/
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#ifndef ZT_SALSA20_HPP
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#define ZT_SALSA20_HPP
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#include <stdio.h>
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#include <stdint.h>
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#include <stdlib.h>
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#include <string.h>
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#include "Constants.hpp"
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#include "Utils.hpp"
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#if (!defined(ZT_SALSA20_SSE)) && (defined(__SSE2__) || defined(__WINDOWS__))
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#define ZT_SALSA20_SSE 1
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#endif
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#ifdef ZT_SALSA20_SSE
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#include <emmintrin.h>
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#endif // ZT_SALSA20_SSE
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namespace ZeroTier {
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/**
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* Salsa20 stream cipher
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*/
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class Salsa20
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{
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public:
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Salsa20() {}
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~Salsa20() { Utils::burn(&_state,sizeof(_state)); }
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/**
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* XOR d with s
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*
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* This is done efficiently using e.g. SSE if available. It's used when
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* alternative Salsa20 implementations are used in Packet and is here
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* since this is where all the SSE stuff is already included.
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*
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* @param d Destination to XOR
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* @param s Source bytes to XOR with destination
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* @param len Length of s and d
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*/
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static inline void memxor(uint8_t *d,const uint8_t *s,unsigned int len)
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{
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#ifdef ZT_SALSA20_SSE
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while (len >= 16) {
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_mm_storeu_si128(reinterpret_cast<__m128i *>(d),_mm_xor_si128(_mm_loadu_si128(reinterpret_cast<__m128i *>(d)),_mm_loadu_si128(reinterpret_cast<const __m128i *>(s))));
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s += 16;
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d += 16;
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len -= 16;
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}
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#else
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#ifndef ZT_NO_TYPE_PUNNING
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while (len >= 16) {
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(*reinterpret_cast<uint64_t *>(d)) ^= (*reinterpret_cast<const uint64_t *>(s));
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s += 8;
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d += 8;
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(*reinterpret_cast<uint64_t *>(d)) ^= (*reinterpret_cast<const uint64_t *>(s));
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s += 8;
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d += 8;
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len -= 16;
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}
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#endif
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#endif
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while (len--)
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*(d++) ^= *(s++);
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}
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/**
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* @param key 256-bit (32 byte) key
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* @param iv 64-bit initialization vector
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*/
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Salsa20(const void *key,const void *iv)
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{
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init(key,iv);
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}
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/**
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* Initialize cipher
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*
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* @param key Key bits
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* @param iv 64-bit initialization vector
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*/
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void init(const void *key,const void *iv);
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/**
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* Encrypt/decrypt data using Salsa20/12
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*
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* @param in Input data
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* @param out Output buffer
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* @param bytes Length of data
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*/
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void crypt12(const void *in,void *out,unsigned int bytes);
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/**
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* Encrypt/decrypt data using Salsa20/20
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*
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* @param in Input data
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* @param out Output buffer
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* @param bytes Length of data
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*/
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void crypt20(const void *in,void *out,unsigned int bytes);
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private:
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union {
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#ifdef ZT_SALSA20_SSE
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__m128i v[4];
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#endif // ZT_SALSA20_SSE
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uint32_t i[16];
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} _state;
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};
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} // namespace ZeroTier
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#endif
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