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derpnet.h
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derpnet.h
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#pragma once
#include <stddef.h>
#include <stdint.h>
#include <stdbool.h>
#ifndef DERPNET_API
# ifdef DERPNET_STATIC
# define DERPNET_API static inline
# else
# define DERPNET_API extern
# endif
#endif
//
// interface
//
typedef struct {
uint8_t Bytes[32];
} DerpKey;
DERPNET_API void DerpNet_CreateNewKey(DerpKey* UserSecret);
DERPNET_API void DerpNet_GetPublicKey(const DerpKey* UserSecret, DerpKey* UserPublic);
typedef struct {
uintptr_t Socket;
void* SocketEvent;
void* CredHandle[2];
void* CtxHandle[2];
uint8_t UserPrivateKey[32];
uint8_t LastPublicKey[32];
uint8_t LastSharedKey[32];
size_t BufferSize;
size_t BufferReceived;
size_t LastFrameSize;
size_t TotalReceived;
size_t TotalSent;
uint8_t Buffer[1 << 16];
} DerpNet;
// use DERP server hostname from https://login.tailscale.com/derpmap/default
DERPNET_API bool DerpNet_Open(DerpNet* Net, const char* DerpServer, const DerpKey* UserSecret);
DERPNET_API void DerpNet_Close(DerpNet* Net);
// returns 1 when received data from other user, pointer is valid till next call
// returns -1 if disconnected from server
// returns 0 if no new info is available to read
// if Wait=true, then never returns 0 - always waits for one incoming message
DERPNET_API int DerpNet_Recv(DerpNet* Net, DerpKey* ReceivedUserPublicKey, uint8_t** ReceivedData, uint32_t* ReceivedSize, bool Wait);
// returns false if disconnected
DERPNET_API bool DerpNet_Send(DerpNet* Net, const DerpKey* TargetUserPublicKey, const void* Data, size_t DataSize);
// use this if you're an expert!
DERPNET_API bool DerpNet_SendEx(DerpNet* Net, const DerpKey* TargetUserPublicKey, const uint8_t SharedKey[32], const uint8_t Nonce[24], const void* Data, size_t DataSize);
//
// implementation
//
#if defined(DERPNET_STATIC) || defined(DERPNET_IMPLEMENTATION)
#include <stdio.h>
#include <string.h>
#define SECURITY_WIN32
#define _WINSOCK_DEPRECATED_NO_WARNINGS
#include <winsock2.h>
#include <windows.h>
#include <ws2tcpip.h>
#include <security.h>
#include <schannel.h>
#include <bcrypt.h>
#pragma comment (lib, "bcrypt")
#pragma comment (lib, "ws2_32")
#pragma comment (lib, "secur32")
//
// helpers
//
#if defined(__SIZEOF_INT128__)
typedef unsigned __int128 uint128;
# define mul64x64_128(out,a,b) out = (uint128)a * b
# define shr128_pair(out,hi,lo,shift) out = (uint64_t)((((uint128)hi << 64) | lo) >> (shift))
# define shl128_pair(out,hi,lo,shift) out = (uint64_t)(((((uint128)hi << 64) | lo) << (shift)) >> 64);
# define shr128(out,in,shift) out = (uint64_t)(in >> (shift))
# define shl128(out,in,shift) out = (uint64_t)((in << shift) >> 64)
# define add128(a,b) a += b
# define add128_64(a,b) a += (uint64_t)b
# define lo128(a) ((uint64_t)a)
# define hi128(a) ((uint64_t)(a >> 64))
#elif defined(_MSC_VER)
typedef struct { uint64_t lo, hi; } uint128;
# include <intrin.h>
# define mul64x64_128(out,a,b) out.lo = _umul128(a,b,&out.hi)
# define shr128_pair(out,hi,lo,shift) out = __shiftright128(lo, hi, shift)
# define shl128_pair(out,hi,lo,shift) out = __shiftleft128(lo, hi, shift)
# define shr128(out,in,shift) shr128_pair(out, in.hi, in.lo, shift)
# define shl128(out,in,shift) shl128_pair(out, in.hi, in.lo, shift)
# define add128(a,b) do { uint64_t p = a.lo; a.lo += b.lo; a.hi += b.hi + (a.lo < p); } while (0)
# define add128_64(a,b) do { uint64_t p = a.lo; a.lo += b; a.hi += (a.lo < p); } while (0)
# define lo128(a) (a.lo)
# define hi128(a) (a.hi)
#else
# error unsupported compiler/target
#endif
#if defined(__clang__)
# define rol32(x, n) __builtin_rotateleft32(x, n)
#elif defined(_MSC_VER)
# define rol32(x, n) _rotl(x, n)
#else
# define rol32(x, n) ( ((x) << (n)) | ((x) >> (32-(n))) )
#endif
#if !defined(NDEBUG)
# define DERPNET_ASSERT(cond) do { if (!(cond)) __debugbreak(); } while (0)
# define DERPNET_LOG(...) do { \
char LogBuffer[256]; \
snprintf(LogBuffer, sizeof(LogBuffer), "DERP: " __VA_ARGS__); \
OutputDebugStringA(LogBuffer); \
OutputDebugStringA("\n"); \
} while (0)
#else
# define DERPNET_ASSERT(cond) do { (void)(cond); } while (0)
# define DERPNET_LOG(...) do { (void)sizeof(__VA_ARGS__); } while (0)
#endif
static inline uint32_t Get32LE(const uint8_t* Buffer)
{
return (Buffer[3] << 24) + (Buffer[2] << 16) + (Buffer[1] << 8) + Buffer[0];
}
static inline uint32_t Get32BE(const uint8_t* Buffer)
{
return (Buffer[0] << 24) + (Buffer[1] << 16) + (Buffer[2] << 8) + Buffer[3];
}
static inline uint64_t Get64LE(const uint8_t* Buffer)
{
return ((uint64_t)Buffer[7] << 56)
+ ((uint64_t)Buffer[6] << 48)
+ ((uint64_t)Buffer[5] << 40)
+ ((uint64_t)Buffer[4] << 32)
+ ((uint64_t)Buffer[3] << 24)
+ ((uint64_t)Buffer[2] << 16)
+ ((uint64_t)Buffer[1] << 8)
+ ((uint64_t)Buffer[0]);
}
static inline void Set32LE(uint8_t* Buffer, uint32_t Value)
{
Buffer[0] = Value;
Buffer[1] = Value >> 8;
Buffer[2] = Value >> 16;
Buffer[3] = Value >> 24;
}
static inline void Set32BE(uint8_t* Buffer, uint32_t Value)
{
Buffer[3] = Value;
Buffer[2] = Value >> 8;
Buffer[1] = Value >> 16;
Buffer[0] = Value >> 24;
}
static inline void Set64LE(uint8_t* Buffer, uint64_t Value)
{
Buffer[0] = (uint8_t)(Value);
Buffer[1] = (uint8_t)(Value >> 8);
Buffer[2] = (uint8_t)(Value >> 16);
Buffer[3] = (uint8_t)(Value >> 24);
Buffer[4] = (uint8_t)(Value >> 32);
Buffer[5] = (uint8_t)(Value >> 40);
Buffer[6] = (uint8_t)(Value >> 48);
Buffer[7] = (uint8_t)(Value >> 56);
}
static inline void DerpNet__GetRandom(void* Buffer, size_t BufferSize)
{
int Status = BCryptGenRandom(NULL, (PUCHAR)Buffer, (ULONG)BufferSize, BCRYPT_USE_SYSTEM_PREFERRED_RNG);
DERPNET_ASSERT(Status == 0);
}
//
// curve25519, based on public domain code from https://github.com/floodyberry/curve25519-donna
//
typedef uint64_t bignum25519[5];
static const uint64_t reduce_mask_51 = (1ULL << 51) - 1;
static void curve25519_copy(bignum25519 out, const bignum25519 in)
{
out[0] = in[0];
out[1] = in[1];
out[2] = in[2];
out[3] = in[3];
out[4] = in[4];
}
static void curve25519_add(bignum25519 out, const bignum25519 a, const bignum25519 b)
{
out[0] = a[0] + b[0];
out[1] = a[1] + b[1];
out[2] = a[2] + b[2];
out[3] = a[3] + b[3];
out[4] = a[4] + b[4];
}
static void curve25519_sub(bignum25519 out, const bignum25519 a, const bignum25519 b)
{
const uint64_t two54m152 = (1ULL << 54) - 152;
const uint64_t two54m8 = (1ULL << 54) - 8;
out[0] = a[0] + two54m152 - b[0];
out[1] = a[1] + two54m8 - b[1];
out[2] = a[2] + two54m8 - b[2];
out[3] = a[3] + two54m8 - b[3];
out[4] = a[4] + two54m8 - b[4];
}
static void curve25519_scalar_product(bignum25519 out, const bignum25519 in, const uint64_t scalar)
{
uint128 a;
uint64_t c;
mul64x64_128(a, in[0], scalar); out[0] = lo128(a) & reduce_mask_51; shr128(c, a, 51);
mul64x64_128(a, in[1], scalar); add128_64(a, c); out[1] = lo128(a) & reduce_mask_51; shr128(c, a, 51);
mul64x64_128(a, in[2], scalar); add128_64(a, c); out[2] = lo128(a) & reduce_mask_51; shr128(c, a, 51);
mul64x64_128(a, in[3], scalar); add128_64(a, c); out[3] = lo128(a) & reduce_mask_51; shr128(c, a, 51);
mul64x64_128(a, in[4], scalar); add128_64(a, c); out[4] = lo128(a) & reduce_mask_51; shr128(c, a, 51);
out[0] += c * 19;
}
static void curve25519_mul(bignum25519 out, const bignum25519 a, const bignum25519 b)
{
uint128 mul;
uint128 t[5];
uint64_t r0,r1,r2,r3,r4,s0,s1,s2,s3,s4,c;
r0 = b[0];
r1 = b[1];
r2 = b[2];
r3 = b[3];
r4 = b[4];
s0 = a[0];
s1 = a[1];
s2 = a[2];
s3 = a[3];
s4 = a[4];
mul64x64_128(t[0], r0, s0);
mul64x64_128(t[1], r0, s1); mul64x64_128(mul, r1, s0); add128(t[1], mul);
mul64x64_128(t[2], r0, s2); mul64x64_128(mul, r2, s0); add128(t[2], mul); mul64x64_128(mul, r1, s1); add128(t[2], mul);
mul64x64_128(t[3], r0, s3); mul64x64_128(mul, r3, s0); add128(t[3], mul); mul64x64_128(mul, r1, s2); add128(t[3], mul); mul64x64_128(mul, r2, s1); add128(t[3], mul);
mul64x64_128(t[4], r0, s4); mul64x64_128(mul, r4, s0); add128(t[4], mul); mul64x64_128(mul, r3, s1); add128(t[4], mul); mul64x64_128(mul, r1, s3); add128(t[4], mul); mul64x64_128(mul, r2, s2); add128(t[4], mul);
r1 *= 19;
r2 *= 19;
r3 *= 19;
r4 *= 19;
mul64x64_128(mul, r4, s1); add128(t[0], mul); mul64x64_128(mul, r1, s4); add128(t[0], mul); mul64x64_128(mul, r2, s3); add128(t[0], mul); mul64x64_128(mul, r3, s2); add128(t[0], mul);
mul64x64_128(mul, r4, s2); add128(t[1], mul); mul64x64_128(mul, r2, s4); add128(t[1], mul); mul64x64_128(mul, r3, s3); add128(t[1], mul);
mul64x64_128(mul, r4, s3); add128(t[2], mul); mul64x64_128(mul, r3, s4); add128(t[2], mul);
mul64x64_128(mul, r4, s4); add128(t[3], mul);
r0 = lo128(t[0]) & reduce_mask_51; shr128(c, t[0], 51);
add128_64(t[1], c); r1 = lo128(t[1]) & reduce_mask_51; shr128(c, t[1], 51);
add128_64(t[2], c); r2 = lo128(t[2]) & reduce_mask_51; shr128(c, t[2], 51);
add128_64(t[3], c); r3 = lo128(t[3]) & reduce_mask_51; shr128(c, t[3], 51);
add128_64(t[4], c); r4 = lo128(t[4]) & reduce_mask_51; shr128(c, t[4], 51);
r0 += c * 19; c = r0 >> 51; r0 = r0 & reduce_mask_51;
r1 += c;
out[0] = r0;
out[1] = r1;
out[2] = r2;
out[3] = r3;
out[4] = r4;
}
static void curve25519_square_times(bignum25519 out, const bignum25519 in, uint64_t count)
{
uint128 mul;
uint128 t[5];
uint64_t r0,r1,r2,r3,r4,c;
uint64_t d0,d1,d2,d4,d419;
r0 = in[0];
r1 = in[1];
r2 = in[2];
r3 = in[3];
r4 = in[4];
do
{
d0 = r0 * 2;
d1 = r1 * 2;
d2 = r2 * 2 * 19;
d419 = r4 * 19;
d4 = d419 * 2;
mul64x64_128(t[0], r0, r0); mul64x64_128(mul, d4, r1); add128(t[0], mul); mul64x64_128(mul, d2, r3); add128(t[0], mul);
mul64x64_128(t[1], d0, r1); mul64x64_128(mul, d4, r2); add128(t[1], mul); mul64x64_128(mul, r3, r3 * 19); add128(t[1], mul);
mul64x64_128(t[2], d0, r2); mul64x64_128(mul, r1, r1); add128(t[2], mul); mul64x64_128(mul, d4, r3); add128(t[2], mul);
mul64x64_128(t[3], d0, r3); mul64x64_128(mul, d1, r2); add128(t[3], mul); mul64x64_128(mul, r4, d419); add128(t[3], mul);
mul64x64_128(t[4], d0, r4); mul64x64_128(mul, d1, r3); add128(t[4], mul); mul64x64_128(mul, r2, r2); add128(t[4], mul);
r0 = lo128(t[0]) & reduce_mask_51; shr128(c, t[0], 51);
add128_64(t[1], c); r1 = lo128(t[1]) & reduce_mask_51; shr128(c, t[1], 51);
add128_64(t[2], c); r2 = lo128(t[2]) & reduce_mask_51; shr128(c, t[2], 51);
add128_64(t[3], c); r3 = lo128(t[3]) & reduce_mask_51; shr128(c, t[3], 51);
add128_64(t[4], c); r4 = lo128(t[4]) & reduce_mask_51; shr128(c, t[4], 51);
r0 += c * 19; c = r0 >> 51; r0 = r0 & reduce_mask_51;
r1 += c;
}
while(--count);
out[0] = r0;
out[1] = r1;
out[2] = r2;
out[3] = r3;
out[4] = r4;
}
static void curve25519_square(bignum25519 out, const bignum25519 in)
{
uint128 mul;
uint128 t[5];
uint64_t r0,r1,r2,r3,r4,c;
uint64_t d0,d1,d2,d4,d419;
r0 = in[0];
r1 = in[1];
r2 = in[2];
r3 = in[3];
r4 = in[4];
d0 = r0 * 2;
d1 = r1 * 2;
d2 = r2 * 2 * 19;
d419 = r4 * 19;
d4 = d419 * 2;
mul64x64_128(t[0], r0, r0); mul64x64_128(mul, d4, r1); add128(t[0], mul); mul64x64_128(mul, d2, r3); add128(t[0], mul);
mul64x64_128(t[1], d0, r1); mul64x64_128(mul, d4, r2); add128(t[1], mul); mul64x64_128(mul, r3, r3 * 19); add128(t[1], mul);
mul64x64_128(t[2], d0, r2); mul64x64_128(mul, r1, r1); add128(t[2], mul); mul64x64_128(mul, d4, r3); add128(t[2], mul);
mul64x64_128(t[3], d0, r3); mul64x64_128(mul, d1, r2); add128(t[3], mul); mul64x64_128(mul, r4, d419); add128(t[3], mul);
mul64x64_128(t[4], d0, r4); mul64x64_128(mul, d1, r3); add128(t[4], mul); mul64x64_128(mul, r2, r2); add128(t[4], mul);
r0 = lo128(t[0]) & reduce_mask_51; shr128(c, t[0], 51);
add128_64(t[1], c); r1 = lo128(t[1]) & reduce_mask_51; shr128(c, t[1], 51);
add128_64(t[2], c); r2 = lo128(t[2]) & reduce_mask_51; shr128(c, t[2], 51);
add128_64(t[3], c); r3 = lo128(t[3]) & reduce_mask_51; shr128(c, t[3], 51);
add128_64(t[4], c); r4 = lo128(t[4]) & reduce_mask_51; shr128(c, t[4], 51);
r0 += c * 19; c = r0 >> 51; r0 = r0 & reduce_mask_51;
r1 += c;
out[0] = r0;
out[1] = r1;
out[2] = r2;
out[3] = r3;
out[4] = r4;
}
static void curve25519_expand(bignum25519 out, const uint8_t* in)
{
uint64_t x0 = Get64LE(&in[ 0]);
uint64_t x1 = Get64LE(&in[ 8]);
uint64_t x2 = Get64LE(&in[16]);
uint64_t x3 = Get64LE(&in[24]);
out[0] = x0 & reduce_mask_51; x0 = (x0 >> 51) | (x1 << 13);
out[1] = x0 & reduce_mask_51; x1 = (x1 >> 38) | (x2 << 26);
out[2] = x1 & reduce_mask_51; x2 = (x2 >> 25) | (x3 << 39);
out[3] = x2 & reduce_mask_51; x3 = (x3 >> 12);
out[4] = x3 & reduce_mask_51; /* ignore the top bit */
}
static void curve25519_contract(uint8_t* out, const bignum25519 input)
{
uint64_t t[5];
uint64_t f;
t[0] = input[0];
t[1] = input[1];
t[2] = input[2];
t[3] = input[3];
t[4] = input[4];
#define curve25519_contract_carry() \
t[1] += t[0] >> 51; t[0] &= reduce_mask_51; \
t[2] += t[1] >> 51; t[1] &= reduce_mask_51; \
t[3] += t[2] >> 51; t[2] &= reduce_mask_51; \
t[4] += t[3] >> 51; t[3] &= reduce_mask_51;
#define curve25519_contract_carry_full() curve25519_contract_carry() \
t[0] += 19 * (t[4] >> 51); t[4] &= reduce_mask_51;
#define curve25519_contract_carry_final() curve25519_contract_carry() \
t[4] &= reduce_mask_51;
curve25519_contract_carry_full()
curve25519_contract_carry_full()
/* now t is between 0 and 2^255-1, properly carried. */
/* case 1: between 0 and 2^255-20. case 2: between 2^255-19 and 2^255-1. */
t[0] += 19;
curve25519_contract_carry_full()
/* now between 19 and 2^255-1 in both cases, and offset by 19. */
t[0] += 0x8000000000000 - 19;
t[1] += 0x8000000000000 - 1;
t[2] += 0x8000000000000 - 1;
t[3] += 0x8000000000000 - 1;
t[4] += 0x8000000000000 - 1;
/* now between 2^255 and 2^256-20, and offset by 2^255. */
curve25519_contract_carry_final()
#define write51full(n,shift) \
f = ((t[n] >> shift) | (t[n+1] << (51 - shift))); \
for (int i = 0; i < 8; i++, f >>= 8) *out++ = (uint8_t)f;
#define write51(n) write51full(n,13*n)
write51(0)
write51(1)
write51(2)
write51(3)
#undef curve25519_contract_carry
#undef curve25519_contract_carry_full
#undef curve25519_contract_carry_final
#undef write51full
#undef write51
}
static void curve25519_swap_conditional(bignum25519 x, bignum25519 qpx, uint64_t iswap)
{
const uint64_t swap = (uint64_t)(-(int64_t)iswap);
uint64_t x0,x1,x2,x3,x4;
x0 = swap & (x[0] ^ qpx[0]); x[0] ^= x0; qpx[0] ^= x0;
x1 = swap & (x[1] ^ qpx[1]); x[1] ^= x1; qpx[1] ^= x1;
x2 = swap & (x[2] ^ qpx[2]); x[2] ^= x2; qpx[2] ^= x2;
x3 = swap & (x[3] ^ qpx[3]); x[3] ^= x3; qpx[3] ^= x3;
x4 = swap & (x[4] ^ qpx[4]); x[4] ^= x4; qpx[4] ^= x4;
}
static void curve25519_pow_two5mtwo0_two250mtwo0(bignum25519 b)
{
bignum25519 t0, c;
/* 2^5 - 2^0 */ /* b */
/* 2^10 - 2^5 */ curve25519_square_times(t0, b, 5);
/* 2^10 - 2^0 */ curve25519_mul(b, t0, b);
/* 2^20 - 2^10 */ curve25519_square_times(t0, b, 10);
/* 2^20 - 2^0 */ curve25519_mul(c, t0, b);
/* 2^40 - 2^20 */ curve25519_square_times(t0, c, 20);
/* 2^40 - 2^0 */ curve25519_mul(t0, t0, c);
/* 2^50 - 2^10 */ curve25519_square_times(t0, t0, 10);
/* 2^50 - 2^0 */ curve25519_mul(b, t0, b);
/* 2^100 - 2^50 */ curve25519_square_times(t0, b, 50);
/* 2^100 - 2^0 */ curve25519_mul(c, t0, b);
/* 2^200 - 2^100 */ curve25519_square_times(t0, c, 100);
/* 2^200 - 2^0 */ curve25519_mul(t0, t0, c);
/* 2^250 - 2^50 */ curve25519_square_times(t0, t0, 50);
/* 2^250 - 2^0 */ curve25519_mul(b, t0, b);
}
static void curve25519_recip(bignum25519 out, const bignum25519 z)
{
bignum25519 a, t0, b;
/* 2 */ curve25519_square(a, z); /* a = 2 */
/* 8 */ curve25519_square_times(t0, a, 2);
/* 9 */ curve25519_mul(b, t0, z); /* b = 9 */
/* 11 */ curve25519_mul(a, b, a); /* a = 11 */
/* 22 */ curve25519_square(t0, a);
/* 2^5 - 2^0 = 31 */ curve25519_mul(b, t0, b);
/* 2^250 - 2^0 */ curve25519_pow_two5mtwo0_two250mtwo0(b);
/* 2^255 - 2^5 */ curve25519_square_times(b, b, 5);
/* 2^255 - 21 */ curve25519_mul(out, b, a);
}
static void curve25519_scalarmult(uint8_t* mypublic, const uint8_t* n, const uint8_t* basepoint)
{
// curve25519-donna-64bit.h
// curve25519-donna-common.h
bignum25519 nqpqx = { 1 }, nqpqz = { 0 }, nqz = { 1 }, nqx;
bignum25519 q, qx, qpqx, qqx, zzz, zmone;
curve25519_expand(q, basepoint);
curve25519_copy(nqx, q);
/* bit 255 is always 0, and bit 254 is always 1, so skip bit 255 and
start pre-swapped on bit 254 */
size_t lastbit = 1;
/* we are doing bits 254..3 in the loop, but are swapping in bits 253..2 */
for (int i = 253; i >= 2; i--)
{
curve25519_add(qx, nqx, nqz);
curve25519_sub(nqz, nqx, nqz);
curve25519_add(qpqx, nqpqx, nqpqz);
curve25519_sub(nqpqz, nqpqx, nqpqz);
curve25519_mul(nqpqx, qpqx, nqz);
curve25519_mul(nqpqz, qx, nqpqz);
curve25519_add(qqx, nqpqx, nqpqz);
curve25519_sub(nqpqz, nqpqx, nqpqz);
curve25519_square(nqpqz, nqpqz);
curve25519_square(nqpqx, qqx);
curve25519_mul(nqpqz, nqpqz, q);
curve25519_square(qx, qx);
curve25519_square(nqz, nqz);
curve25519_mul(nqx, qx, nqz);
curve25519_sub(nqz, qx, nqz);
curve25519_scalar_product(zzz, nqz, 121665);
curve25519_add(zzz, zzz, qx);
curve25519_mul(nqz, nqz, zzz);
size_t bit = (n[i/8] >> (i & 7)) & 1;
curve25519_swap_conditional(nqx, nqpqx, bit ^ lastbit);
curve25519_swap_conditional(nqz, nqpqz, bit ^ lastbit);
lastbit = bit;
}
/* the final 3 bits are always zero, so we only need to double */
for (int i = 0; i < 3; i++)
{
curve25519_add(qx, nqx, nqz);
curve25519_sub(nqz, nqx, nqz);
curve25519_square(qx, qx);
curve25519_square(nqz, nqz);
curve25519_mul(nqx, qx, nqz);
curve25519_sub(nqz, qx, nqz);
curve25519_scalar_product(zzz, nqz, 121665);
curve25519_add(zzz, zzz, qx);
curve25519_mul(nqz, nqz, zzz);
}
curve25519_recip(zmone, nqz);
curve25519_mul(nqz, nqx, zmone);
curve25519_contract(mypublic, nqz);
}
//
// poly1305, based on public domain code from https://github.com/floodyberry/poly1305-donna
//
#define poly1305_block_size 16
typedef struct {
uint64_t r[3];
uint64_t h[3];
uint64_t pad[2];
size_t leftover;
unsigned char buffer[poly1305_block_size];
unsigned char final;
} poly1305_state_internal_t;
static void poly1305_init(poly1305_state_internal_t* st, const uint8_t key[32])
{
/* r &= 0xffffffc0ffffffc0ffffffc0fffffff */
uint64_t t0 = Get64LE(&key[0]);
uint64_t t1 = Get64LE(&key[8]);
st->r[0] = ( t0 ) & 0xffc0fffffff;
st->r[1] = ((t0 >> 44) | (t1 << 20)) & 0xfffffc0ffff;
st->r[2] = ((t1 >> 24) ) & 0x00ffffffc0f;
/* h = 0 */
st->h[0] = 0;
st->h[1] = 0;
st->h[2] = 0;
/* save pad for later */
st->pad[0] = Get64LE(&key[16]);
st->pad[1] = Get64LE(&key[24]);
st->leftover = 0;
st->final = 0;
}
static void poly1305_blocks(poly1305_state_internal_t* st, const uint8_t* m, size_t bytes)
{
const uint64_t hibit = (st->final) ? 0 : (1ULL << 40); /* 1 << 128 */
uint64_t r0,r1,r2;
uint64_t s1,s2;
uint64_t h0,h1,h2;
uint64_t c;
uint128 d0,d1,d2,d;
r0 = st->r[0];
r1 = st->r[1];
r2 = st->r[2];
h0 = st->h[0];
h1 = st->h[1];
h2 = st->h[2];
s1 = r1 * (5 << 2);
s2 = r2 * (5 << 2);
while (bytes >= poly1305_block_size)
{
/* h += m[i] */
uint64_t t0 = Get64LE(&m[0]);
uint64_t t1 = Get64LE(&m[8]);
h0 += (( t0 ) & 0xfffffffffff);
h1 += (((t0 >> 44) | (t1 << 20)) & 0xfffffffffff);
h2 += (((t1 >> 24) ) & 0x3ffffffffff) | hibit;
/* h *= r */
mul64x64_128(d0, h0, r0); mul64x64_128(d, h1, s2); add128(d0, d); mul64x64_128(d, h2, s1); add128(d0, d);
mul64x64_128(d1, h0, r1); mul64x64_128(d, h1, r0); add128(d1, d); mul64x64_128(d, h2, s2); add128(d1, d);
mul64x64_128(d2, h0, r2); mul64x64_128(d, h1, r1); add128(d2, d); mul64x64_128(d, h2, r0); add128(d2, d);
/* (partial) h %= p */
shr128(c, d0, 44); h0 = lo128(d0) & 0xfffffffffff;
add128_64(d1, c); shr128(c, d1, 44); h1 = lo128(d1) & 0xfffffffffff;
add128_64(d2, c); shr128(c, d2, 42); h2 = lo128(d2) & 0x3ffffffffff;
h0 += c * 5; c = (h0 >> 44); h0 = h0 & 0xfffffffffff;
h1 += c;
m += poly1305_block_size;
bytes -= poly1305_block_size;
}
st->h[0] = h0;
st->h[1] = h1;
st->h[2] = h2;
}
void poly1305_finish(poly1305_state_internal_t* st, uint8_t mac[16])
{
uint64_t h0,h1,h2,c;
uint64_t g0,g1,g2;
uint64_t t0,t1;
/* process the remaining block */
if (st->leftover)
{
size_t i = st->leftover;
st->buffer[i] = 1;
for (i = i + 1; i < poly1305_block_size; i++)
st->buffer[i] = 0;
st->final = 1;
poly1305_blocks(st, st->buffer, poly1305_block_size);
}
/* fully carry h */
h0 = st->h[0];
h1 = st->h[1];
h2 = st->h[2];
c = (h1 >> 44); h1 &= 0xfffffffffff;
h2 += c; c = (h2 >> 42); h2 &= 0x3ffffffffff;
h0 += c * 5; c = (h0 >> 44); h0 &= 0xfffffffffff;
h1 += c; c = (h1 >> 44); h1 &= 0xfffffffffff;
h2 += c; c = (h2 >> 42); h2 &= 0x3ffffffffff;
h0 += c * 5; c = (h0 >> 44); h0 &= 0xfffffffffff;
h1 += c;
/* compute h + -p */
g0 = h0 + 5; c = (g0 >> 44); g0 &= 0xfffffffffff;
g1 = h1 + c; c = (g1 >> 44); g1 &= 0xfffffffffff;
g2 = h2 + c - (1ULL << 42);
/* select h if h < p, or h + -p if h >= p */
c = (g2 >> ((sizeof(uint64_t) * 8) - 1)) - 1;
g0 &= c;
g1 &= c;
g2 &= c;
c = ~c;
h0 = (h0 & c) | g0;
h1 = (h1 & c) | g1;
h2 = (h2 & c) | g2;
/* h = (h + pad) */
t0 = st->pad[0];
t1 = st->pad[1];
h0 += (( t0 ) & 0xfffffffffff) ; c = (h0 >> 44); h0 &= 0xfffffffffff;
h1 += (((t0 >> 44) | (t1 << 20)) & 0xfffffffffff) + c; c = (h1 >> 44); h1 &= 0xfffffffffff;
h2 += (((t1 >> 24) ) & 0x3ffffffffff) + c; h2 &= 0x3ffffffffff;
/* mac = h % (2^128) */
h0 = ((h0 ) | (h1 << 44));
h1 = ((h1 >> 20) | (h2 << 24));
Set64LE(&mac[0], h0);
Set64LE(&mac[8], h1);
}
static void poly1305_update(poly1305_state_internal_t* st, const uint8_t* m, size_t bytes)
{
/* handle leftover */
if (st->leftover)
{
size_t want = (poly1305_block_size - st->leftover);
if (want > bytes)
want = bytes;
memcpy(st->buffer + st->leftover, m, want);
bytes -= want;
m += want;
st->leftover += want;
if (st->leftover < poly1305_block_size)
return;
poly1305_blocks(st, st->buffer, poly1305_block_size);
st->leftover = 0;
}
/* process full blocks */
if (bytes >= poly1305_block_size)
{
size_t want = (bytes & ~(poly1305_block_size - 1));
poly1305_blocks(st, m, want);
m += want;
bytes -= want;
}
/* store leftover */
if (bytes)
{
memcpy(st->buffer + st->leftover, m, bytes);
st->leftover += bytes;
}
}
static void poly1305_auth(uint8_t mac[16], const uint8_t* m, size_t bytes, const uint8_t key[32])
{
poly1305_state_internal_t st;
poly1305_init(&st, key);
poly1305_update(&st, m, bytes);
poly1305_finish(&st, mac);
}
static int poly1305_verify(const uint8_t mac1[16], const uint8_t mac2[16])
{
uint64_t a1, a2, b1, b2;
memcpy(&a1, mac1 + 0, sizeof(a1));
memcpy(&a2, mac1 + 8, sizeof(a2));
memcpy(&b1, mac2 + 0, sizeof(b1));
memcpy(&b2, mac2 + 8, sizeof(b2));
return ((a1 ^ b1) | (a2 ^ b2)) == 0;
}
//
// salsa20, based on info from https://en.wikipedia.org/wiki/Salsa20#Structure
//
static void salsa20_rounds(uint32_t x[16])
{
for (int i = 0; i < 20; i += 2)
{
uint32_t t;
#define Q(a,b,c,d) \
t = x[a] + x[d]; x[b] ^= rol32(t, 7); \
t = x[b] + x[a]; x[c] ^= rol32(t, 9); \
t = x[c] + x[b]; x[d] ^= rol32(t, 13); \
t = x[d] + x[c]; x[a] ^= rol32(t, 18)
Q( 0, 4, 8, 12);
Q( 5, 9, 13, 1);
Q(10, 14, 2, 6);
Q(15, 3, 7, 11);
Q( 0, 1, 2, 3);
Q( 5, 6, 7, 4);
Q(10, 11, 8, 9);
Q(15, 12, 13, 14);
#undef Q
}
}
static const char salsa20_constant[] = "expand 32-byte k";
static void hsalsa20(uint8_t Output[32], const uint8_t Input[16], const uint8_t Key[32])
{
uint32_t x[16];
x[ 0] = Get32LE((uint8_t*)&salsa20_constant[0]);
x[ 1] = Get32LE(&Key[ 0]);
x[ 2] = Get32LE(&Key[ 4]);
x[ 3] = Get32LE(&Key[ 8]);
x[ 4] = Get32LE(&Key[12]);
x[ 5] = Get32LE((uint8_t*)&salsa20_constant[4]);
x[ 6] = Get32LE(&Input[ 0]);
x[ 7] = Get32LE(&Input[ 4]);
x[ 8] = Get32LE(&Input[ 8]);
x[ 9] = Get32LE(&Input[12]);
x[10] = Get32LE((uint8_t*)&salsa20_constant[8]);
x[11] = Get32LE(&Key[16]);
x[12] = Get32LE(&Key[20]);
x[13] = Get32LE(&Key[24]);
x[14] = Get32LE(&Key[28]);
x[15] = Get32LE((uint8_t*)&salsa20_constant[12]);
salsa20_rounds(x);
Set32LE(&Output[ 0], x[ 0]);
Set32LE(&Output[ 4], x[ 5]);
Set32LE(&Output[ 8], x[10]);
Set32LE(&Output[12], x[15]);
Set32LE(&Output[16], x[ 6]);
Set32LE(&Output[20], x[ 7]);
Set32LE(&Output[24], x[ 8]);
Set32LE(&Output[28], x[ 9]);
}
static void salsa20(uint8_t Output[64], const uint8_t Input[16], const uint8_t Key[32])
{
uint32_t x[16];
x[ 0] = Get32LE((uint8_t*)&salsa20_constant[0]);
x[ 1] = Get32LE(&Key[ 0]);
x[ 2] = Get32LE(&Key[ 4]);
x[ 3] = Get32LE(&Key[ 8]);
x[ 4] = Get32LE(&Key[12]);
x[ 5] = Get32LE((uint8_t*)&salsa20_constant[4]);
x[ 6] = Get32LE(&Input[ 0]);
x[ 7] = Get32LE(&Input[ 4]);
x[ 8] = Get32LE(&Input[ 8]);
x[ 9] = Get32LE(&Input[12]);
x[10] = Get32LE((uint8_t*)&salsa20_constant[8]);
x[11] = Get32LE(&Key[16]);
x[12] = Get32LE(&Key[20]);
x[13] = Get32LE(&Key[24]);
x[14] = Get32LE(&Key[28]);
x[15] = Get32LE((uint8_t*)&salsa20_constant[12]);
uint32_t j[16];
memcpy(j, x, sizeof(j));
salsa20_rounds(x);
for (int i = 0; i < 16; i++)
{
Set32LE(&Output[i * 4], x[i] + j[i]);
}
}
static void salsa20_xor(uint8_t* Output, const uint8_t* Input, size_t InputSize, const uint8_t Key[32], const uint8_t Nonce[8], uint64_t Counter)
{
uint8_t TempInput[16];
uint8_t Block[64];
memcpy(TempInput, Nonce, 8);
while (InputSize >= 64)
{
memcpy(TempInput + 8, &Counter, sizeof(Counter));
salsa20(Block, TempInput, Key);
for (size_t i = 0; i < 64; ++i)
{
Output[i] = Input[i] ^ Block[i];
}
Counter += 1;
Output += 64;
Input += 64;
InputSize -= 64;
}
if (InputSize)
{
memcpy(TempInput + 8, &Counter, sizeof(Counter));
salsa20(Block, TempInput, Key);
for (size_t i = 0; i < InputSize; ++i)
{
Output[i] = Input[i] ^ Block[i];
}
}
}
//
// nacl box seal/unseal
//
static void DerpNet__GetSharedKey(uint8_t SharedKey[32], const uint8_t PrivateKey[32], const uint8_t PublicKey[32])
{
uint8_t SharedSecret[32];
curve25519_scalarmult(SharedSecret, PrivateKey, PublicKey);
uint8_t ZeroInput[16] = { 0 };
hsalsa20(SharedKey, ZeroInput, SharedSecret);
}
static void DerpNet__BoxSealEx(uint8_t Nonce[24], uint8_t Auth[16], uint8_t* Output, const uint8_t* Input, size_t InputSize, const uint8_t SharedKey[32])
{
// xsalsa20 key construction
uint8_t SubKey[32];
hsalsa20(SubKey, Nonce, SharedKey);
uint8_t FirstBlock[64] = { 0 };
salsa20_xor(FirstBlock, FirstBlock, sizeof(FirstBlock), SubKey, Nonce + 16, 0);
size_t FirstSize = InputSize > 32 ? 32 : InputSize;
for (size_t i = 0; i < FirstSize; i++)
{
Output[i] = Input[i] ^ FirstBlock[32 + i];
}
salsa20_xor(Output + FirstSize, Input + FirstSize, InputSize - FirstSize, SubKey, Nonce + 16, 1);
poly1305_auth(Auth, Output, InputSize, FirstBlock);
}
static void DerpNet__BoxSeal(uint8_t Nonce[24], uint8_t Auth[16], uint8_t* Output, const uint8_t* Input, size_t InputSize, const uint8_t PrivateKey[32], const uint8_t PublicKey[32])
{
uint8_t SharedKey[32];
DerpNet__GetSharedKey(SharedKey, PrivateKey, PublicKey);
DerpNet__GetRandom(Nonce, 24);
DerpNet__BoxSealEx(Nonce, Auth, Output, Input, InputSize, SharedKey);
}
static bool DerpNet__BoxUnsealEx(uint8_t* Output, const uint8_t* Input, size_t InputSize, const uint8_t Auth[16], const uint8_t Nonce[24], const uint8_t SharedKey[32])
{
// xsalsa20 key construction
uint8_t SubKey[32];
hsalsa20(SubKey, Nonce, SharedKey);
uint8_t FirstBlock[64] = { 0 };
salsa20_xor(FirstBlock, FirstBlock, sizeof(FirstBlock), SubKey, Nonce + 16, 0);
uint8_t ExpectedAuth[16];
poly1305_auth(ExpectedAuth, Input, InputSize, FirstBlock);
if (poly1305_verify(Auth, ExpectedAuth) == 0)
{
return false;
}
size_t FirstSize = InputSize > 32 ? 32 : InputSize;
for (size_t i = 0; i < FirstSize; i++)
{
Output[i] = Input[i] ^ FirstBlock[32 + i];
}
salsa20_xor(Output + FirstSize, Input + FirstSize, InputSize - FirstSize, SubKey, Nonce + 16, 1);
return true;
}
static bool DerpNet__BoxUnseal(uint8_t* Output, const uint8_t* Input, size_t InputSize, const uint8_t Auth[16], const uint8_t Nonce[24], const uint8_t PrivateKey[32], const uint8_t PublicKey[32])
{
uint8_t SharedKey[32];
DerpNet__GetSharedKey(SharedKey, PrivateKey, PublicKey);
return DerpNet__BoxUnsealEx(Output, Input, InputSize, Auth, Nonce, SharedKey);
}
void DerpNet_CreateNewKey(DerpKey* UserSecret)
{
DerpNet__GetRandom(UserSecret->Bytes, sizeof(UserSecret->Bytes));
UserSecret->Bytes[ 0] &= 0xf8;
UserSecret->Bytes[31] &= 0x7f;
UserSecret->Bytes[31] |= 0x40;
}
void DerpNet_GetPublicKey(const DerpKey* UserSecret, DerpKey* UserPublic)
{
static const uint8_t Base[32] = { 9 };
curve25519_scalarmult(UserPublic->Bytes, UserSecret->Bytes, Base);
}
static bool DerpNet__TlsHandshake(DerpNet* Net, const char* Hostname, CredHandle* CredentialHandle, CtxtHandle* ContextHandle)
{
SCHANNEL_CRED Cred = { 0 };
Cred.dwVersion = SCHANNEL_CRED_VERSION;
Cred.dwFlags = SCH_USE_STRONG_CRYPTO | SCH_CRED_AUTO_CRED_VALIDATION | SCH_CRED_NO_DEFAULT_CREDS;
Cred.grbitEnabledProtocols = SP_PROT_TLS1_2;
SECURITY_STATUS SecStatus = AcquireCredentialsHandleA(NULL, UNISP_NAME_A, SECPKG_CRED_OUTBOUND, NULL, &Cred, NULL, NULL, CredentialHandle, NULL);
DERPNET_ASSERT(SecStatus == SEC_E_OK);
CtxtHandle* Context = NULL;
for (;;)
{
SecBuffer InBuffers[2] = { 0 };
InBuffers[0].BufferType = SECBUFFER_TOKEN;
InBuffers[0].pvBuffer = Net->Buffer;
InBuffers[0].cbBuffer = (unsigned)Net->BufferReceived;
InBuffers[1].BufferType = SECBUFFER_EMPTY;