266 lines
7 KiB
C++
266 lines
7 KiB
C++
/*
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* Copyright (c)2013-2020 ZeroTier, Inc.
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*
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* Use of this software is governed by the Business Source License included
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* in the LICENSE.TXT file in the project's root directory.
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*
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* Change Date: 2026-01-01
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*
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* On the date above, in accordance with the Business Source License, use
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* of this software will be governed by version 2.0 of the Apache License.
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*/
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#ifndef ZT_N_CAMOPATTERN_HPP
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#define ZT_N_CAMOPATTERN_HPP
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#include <stdint.h>
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#include <array>
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#include <unordered_map>
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#include <mutex>
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#include <random>
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#include <bitset>
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#include "Address.hpp"
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#include "Buffer.hpp"
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#include "RuntimeEnvironment.hpp"
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#define BYTES_IN_WORD (sizeof(uint32_t) / sizeof(uint8_t))
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#define ID_SIZE (BYTES_IN_WORD * 2)
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/**
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* Camo functions debug trace macro
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* Enables debug output when CAMO_TRACE is defined
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*/
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#ifdef CAMO_TRACE
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#define CT(...) do { \
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printf("%s:%d %s: ", __FILE__, __LINE__, __PRETTY_FUNCTION__); \
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printf(__VA_ARGS__); \
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printf("\n"); \
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} while(0)
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#else
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#define CT(...) ((void)0)
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#endif
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namespace ZeroTier {
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/**
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* Camouflage class enum
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*/
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enum CamoClass {
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NODE,
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CONTROLLER,
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MOON,
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AUTO_APPLY_COUNT,
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ALWAYS = AUTO_APPLY_COUNT,
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NEVER
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};
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typedef std::bitset<CamoClass::AUTO_APPLY_COUNT> CamoAutoApplyBits;
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typedef std::array<uint8_t, BYTES_IN_WORD> CamoPatternBytes;
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typedef std::unordered_map<Address, CamoClass> KnownHostsMap;
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}
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/**
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* Hash function for the KnownHostsMap
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*/
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namespace std {
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template<>
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struct hash<ZeroTier::Address> {
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size_t operator()(const ZeroTier::Address& address) const {
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return std::hash<uint64_t>{}(address.toInt());
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}
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};
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}
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namespace ZeroTier {
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enum class CamoRelayRule {
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LEAVE,
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KNOWNHOSTS,
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STRIP,
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APPLY
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};
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/**
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* Helper class for packet camouflage operations
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*/
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class CamoPattern
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{
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/**
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* Check if the buffer has camo
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*
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* @param buffer Buffer to check
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* @return True if the buffer has camo
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*/
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template<unsigned int C>
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static bool hasCamo(const Buffer<C> &buffer)
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{
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bool result = false;
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if (buffer.size() > (ID_SIZE * 2))
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{
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size_t a = 0;
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size_t b = BYTES_IN_WORD;
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size_t x = buffer.size() - ID_SIZE;
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size_t y = buffer.size() - BYTES_IN_WORD;
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result = true;
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for (size_t i = 0; i < BYTES_IN_WORD; i++)
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{
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if ((buffer[a + i] ^ buffer[b + i]) != (buffer[x + i] ^ buffer [y + i]))
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{
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result = false;
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break;
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}
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}
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}
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CT("PACKET HAS CAMO: %b", result);
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return result;
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}
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/**
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* Check the host camo class
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*
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* @param host Destination address
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* @param RR RuntimeEnvironment pointer
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* @return Camo class for this host
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*/
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static CamoClass getCamoClass(const Address host, const RuntimeEnvironment * const RR);
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public:
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/**
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* Determine if camouflage is required for a specific host
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*
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* @param host Destination address
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* @param RR RuntimeEnvironment pointer
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* @param hadCamo Whether the packet previously had camouflage applied
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* @param isRelay Whether this is a relay operation
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* @return True if host requires camouflage
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*/
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static bool isCamoRequired(const Address host, const RuntimeEnvironment * const RR, const bool hadCamo = false, const bool isRelay = false);
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/**
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* Apply camouflage to buffer
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*
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* This increases buffer length by adding ID to the end
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*
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* @param buffer Buffer to apply camouflage to
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*/
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template<unsigned int C>
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static void applyCamo(Buffer<C> &buffer)
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{
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CT("APPLYING CAMO");
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if (isInitialized && !hasCamo(buffer))
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{
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// load random number into an array
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uint32_t camo = rng();
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CamoPatternBytes camoBytes;
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for (size_t i = 0; i < BYTES_IN_WORD; i++)
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{
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camoBytes[i] = camo >> 24;
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CT("CAMO BYTE %u: %02x", i, camoBytes[i]);
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camo <<= 8;
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}
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//camouflage all the data
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uint8_t * const data = reinterpret_cast<uint8_t * const>(buffer.unsafeData());
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for (size_t i = ID_SIZE; i < buffer.size(); i++)
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{
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data[i] ^= camoBytes[i % BYTES_IN_WORD];
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}
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// expand the buffer
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size_t originalSize = buffer.size();
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buffer.setSize(originalSize + ID_SIZE);
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//copy the id
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for (size_t i = 0; i < ID_SIZE; i++)
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{
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data[i + originalSize] = data[i] ^ camoBytes[i % BYTES_IN_WORD];
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}
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CT("DONE");
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}
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}
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/**
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* Remove camouflage from buffer
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*
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* This decreases buffer length by removing stored ID from the end
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*
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* @param buffer Buffer to remove camouflage from
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* @return True if buffer had camouflage and it was stripped
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*/
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template<unsigned int C>
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static bool stripCamo(Buffer<C> &buffer)
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{
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bool result = false;
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if (isInitialized && hasCamo(buffer)) {
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//retrieve the camo bytes
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uint8_t * a = &buffer[0];
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uint8_t * x = &buffer[buffer.size() - ID_SIZE];
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CamoPatternBytes camoBytes;
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for (size_t i = 0; i < BYTES_IN_WORD; i++)
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{
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camoBytes[i] = a[i] ^ x[i];
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CT("CAMO BYTE %u: %02x", i, camoBytes[i]);
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}
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//remove the duplicated id
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buffer.setSize(buffer.size() - ID_SIZE);
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//strip camo
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uint8_t * const data = reinterpret_cast<uint8_t * const>(buffer.unsafeData());
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for (size_t i = ID_SIZE; i < buffer.size(); i++)
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{
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data[i] ^= camoBytes[i % BYTES_IN_WORD];
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}
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result = true;
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}
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CT("CAMO STRIPPED: %d", result);
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return result;
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}
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/**
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* Initialize the camo system
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*
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* @param autoApply Bits controlling automatic application to different host classes
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* @param hosts knownHosts preloading
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* @param relayRule Packet relay rule
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*/
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static void init(CamoAutoApplyBits autoApply, KnownHostsMap hosts, CamoRelayRule rule);
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private:
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static bool isInitialized;
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static CamoAutoApplyBits camoAutoApply;
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static CamoRelayRule relayRule;
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static std::mutex camoMutex;
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static KnownHostsMap knownHosts;
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static std::mt19937 rng;
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};
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} // namespace ZeroTier
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// Implementation of Buffer::dump() method
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template<unsigned int C>
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void ZeroTier::Buffer<C>::dump() const
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{
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#ifdef CAMO_TRACE
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const unsigned char *bytes = reinterpret_cast<const unsigned char *>(data());
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const unsigned int size = this->size();
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for (unsigned int i = 0; i < size; i++) {
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printf("%02x", bytes[i]);
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if ((i + 1) % 16 == 0) {
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printf("\n");
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} else if (i < size - 1) {
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printf(" ");
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}
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}
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// Add newline if last line wasn't complete
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if (size % 16 != 0) {
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printf("\n");
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}
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#endif
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}
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#endif // ZT_CAMOPATTERN_HPP
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