ZeroTierOne/node/Protocol.cpp
2020-02-07 00:02:29 -08:00

136 lines
4.2 KiB
C++

/*
* Copyright (c)2013-2020 ZeroTier, Inc.
*
* Use of this software is governed by the Business Source License included
* in the LICENSE.TXT file in the project's root directory.
*
* Change Date: 2024-01-01
*
* On the date above, in accordance with the Business Source License, use
* of this software will be governed by version 2.0 of the Apache License.
*/
/****/
#include "Protocol.hpp"
#include "Buf.hpp"
#include "Utils.hpp"
#include <cstdlib>
#include <stdexcept>
#if defined(__GCC__) && (defined(__amd64) || defined(__amd64__) || defined(__x86_64) || defined(__x86_64__) || defined(__AMD64) || defined(__AMD64__) || defined(_M_X64))
#define ZT_PACKET_USE_ATOMIC_INTRINSICS
#endif
#ifndef ZT_PACKET_USE_ATOMIC_INTRINSICS
#include <atomic>
#endif
namespace ZeroTier {
namespace Protocol {
namespace {
unsigned long long _initPacketID()
{
unsigned long long tmp = 0;
Utils::getSecureRandom(&tmp,sizeof(tmp));
tmp >>= 31U;
tmp |= (((uint64_t)time(nullptr)) & 0xffffffffULL) << 33U;
return tmp;
}
#ifdef ZT_PACKET_USE_ATOMIC_INTRINSICS
unsigned long long _packetIdCtr = _initPacketID();
#else
static std::atomic<unsigned long long> _packetIdCtr(_initPacketID());
#endif
uintptr_t _checkStructureSizing()
{
if (sizeof(Header) != ZT_PROTO_MIN_PACKET_LENGTH)
throw std::runtime_error("sizeof(Header) != ZT_PROTO_MIN_PACKET_LENGTH");
if (sizeof(FragmentHeader) != ZT_PROTO_MIN_FRAGMENT_LENGTH)
throw std::runtime_error("sizeof(FragmentHeader) != ZT_PROTO_MIN_FRAGMENT_LENGTH");
return (uintptr_t)Utils::getSecureRandomU64(); // also prevents compiler from optimizing out
}
} // anonymous namespace
volatile uintptr_t _compileTimeStructCheckHappened = _checkStructureSizing();
uint64_t getPacketId()
{
#ifdef ZT_PACKET_USE_ATOMIC_INTRINSICS
return __sync_add_and_fetch(&_packetIdCtr,1ULL);
#else
return ++_packetIdCtr;
#endif
}
void armor(Buf &pkt,unsigned int packetSize,const uint8_t key[ZT_PEER_SECRET_KEY_LENGTH],uint8_t cipherSuite)
{
Protocol::Header &ph = pkt.as<Protocol::Header>();
ph.flags = (ph.flags & 0xc7U) | ((cipherSuite << 3U) & 0x38U); // flags: FFCCCHHH where CCC is cipher
switch(cipherSuite) {
case ZT_PROTO_CIPHER_SUITE__POLY1305_NONE: {
uint8_t perPacketKey[ZT_PEER_SECRET_KEY_LENGTH];
salsa2012DeriveKey(key,perPacketKey,pkt,packetSize);
Salsa20 s20(perPacketKey,&ph.packetId);
uint8_t macKey[ZT_POLY1305_KEY_LEN];
s20.crypt12(Utils::ZERO256,macKey,ZT_POLY1305_KEY_LEN);
// only difference here is that we don't encrypt the payload
uint64_t mac[2];
poly1305(mac,pkt.b + ZT_PROTO_PACKET_ENCRYPTED_SECTION_START,packetSize - ZT_PROTO_PACKET_ENCRYPTED_SECTION_START,macKey);
ph.mac = mac[0];
} break;
case ZT_PROTO_CIPHER_SUITE__POLY1305_SALSA2012: {
uint8_t perPacketKey[ZT_PEER_SECRET_KEY_LENGTH];
salsa2012DeriveKey(key,perPacketKey,pkt,packetSize);
Salsa20 s20(perPacketKey,&ph.packetId);
uint8_t macKey[ZT_POLY1305_KEY_LEN];
s20.crypt12(Utils::ZERO256,macKey,ZT_POLY1305_KEY_LEN);
const unsigned int encLen = packetSize - ZT_PROTO_PACKET_ENCRYPTED_SECTION_START;
s20.crypt12(pkt.b + ZT_PROTO_PACKET_ENCRYPTED_SECTION_START,pkt.b + ZT_PROTO_PACKET_ENCRYPTED_SECTION_START,encLen);
uint64_t mac[2];
poly1305(mac,pkt.b + ZT_PROTO_PACKET_ENCRYPTED_SECTION_START,encLen,macKey);
ph.mac = mac[0];
} break;
case ZT_PROTO_CIPHER_SUITE__AES_GCM_NRH: {
} break;
}
}
unsigned int compress(SharedPtr<Buf> &pkt,unsigned int packetSize)
{
if (packetSize <= 128)
return packetSize;
SharedPtr<Buf> pkt2(Buf::get());
if (!pkt2) return packetSize;
const unsigned int uncompressedLen = packetSize - ZT_PROTO_PACKET_PAYLOAD_START;
const int compressedLen = LZ4_compress_fast(
reinterpret_cast<const char *>(pkt->b + ZT_PROTO_PACKET_PAYLOAD_START),
reinterpret_cast<char *>(pkt2->b + ZT_PROTO_PACKET_PAYLOAD_START),
(int)uncompressedLen,
ZT_BUF_MEM_SIZE - ZT_PROTO_PACKET_PAYLOAD_START);
if ((compressedLen > 0)&&(compressedLen < (int)uncompressedLen)) {
memcpy(pkt2->b,pkt->b,ZT_PROTO_PACKET_PAYLOAD_START);
pkt.swap(pkt2);
pkt->as<Protocol::Header>().verb |= ZT_PROTO_VERB_FLAG_COMPRESSED;
return (unsigned int)compressedLen + ZT_PROTO_PACKET_PAYLOAD_START;
}
return packetSize;
}
} // namespace Protocol
} // namespace ZeroTier