Adam Ierymenko
10 years ago
7 changed files with 0 additions and 175 deletions
@ -1,135 +0,0 @@
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/*
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* ZeroTier One - Network Virtualization Everywhere |
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* Copyright (C) 2011-2015 ZeroTier, Inc. |
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* |
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* This program is free software: you can redistribute it and/or modify |
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* it under the terms of the GNU General Public License as published by |
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* the Free Software Foundation, either version 3 of the License, or |
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* (at your option) any later version. |
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* |
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* This program is distributed in the hope that it will be useful, |
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* but WITHOUT ANY WARRANTY; without even the implied warranty of |
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
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* GNU General Public License for more details. |
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* |
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* You should have received a copy of the GNU General Public License |
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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* |
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* -- |
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* |
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* ZeroTier may be used and distributed under the terms of the GPLv3, which |
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* are available at: http://www.gnu.org/licenses/gpl-3.0.html
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* |
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* If you would like to embed ZeroTier into a commercial application or |
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* redistribute it in a modified binary form, please contact ZeroTier Networks |
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* LLC. Start here: http://www.zerotier.com/
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*/ |
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#ifndef ZT_ANTIRECURSION_HPP |
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#define ZT_ANTIRECURSION_HPP |
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#include <string.h> |
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#include <stdlib.h> |
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#include "Constants.hpp" |
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namespace ZeroTier { |
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/**
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* Size of anti-recursion history |
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*/ |
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#define ZT_ANTIRECURSION_HISTORY_SIZE 16 |
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/**
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* Filter to prevent recursion (ZeroTier-over-ZeroTier) |
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* |
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* This works by logging ZeroTier packets that we send. It's then invoked |
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* again against packets read from local Ethernet taps. If the last 32 |
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* bytes representing the ZeroTier packet match in the tap frame, then |
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* the frame is a re-injection of a frame that we sent and is rejected. |
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* |
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* This means that ZeroTier packets simply will not traverse ZeroTier |
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* networks, which would cause all sorts of weird problems. |
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* |
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* This is highly optimized code since it's checked for every packet. |
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*/ |
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class AntiRecursion |
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{ |
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public: |
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AntiRecursion() |
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{ |
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for(int i=0;i<ZT_ANTIRECURSION_HISTORY_SIZE;++i) { |
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_history[i].tail[0] = 0; |
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_history[i].tail[1] = 0; |
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_history[i].tail[2] = 0; |
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_history[i].tail[3] = 0; |
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} |
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_ptr = 0; |
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} |
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/**
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* Add an outgoing ZeroTier packet to the circular log |
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* |
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* @param data ZT packet data |
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* @param len Length of packet |
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*/ |
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inline void logOutgoingZT(const void *const data,const unsigned int len) |
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{ |
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if (len < 32) |
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return; |
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#ifdef ZT_NO_TYPE_PUNNING |
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memcpy(_history[++_ptr % ZT_ANTIRECURSION_HISTORY_SIZE].tail,reinterpret_cast<const uint8_t *>(data) + (len - 32),32); |
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#else |
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uint64_t *t = _history[++_ptr % ZT_ANTIRECURSION_HISTORY_SIZE].tail; |
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const uint64_t *p = reinterpret_cast<const uint64_t *>(reinterpret_cast<const uint8_t *>(data) + (len - 32)); |
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*(t++) = *(p++); |
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*(t++) = *(p++); |
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*(t++) = *(p++); |
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*t = *p; |
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#endif |
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} |
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/**
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* Check an ethernet frame from a local tap against anti-recursion history |
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* |
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* @param data Raw frame data |
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* @param len Length of frame |
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* @return True if frame is OK to be passed, false if it's a ZT frame that we sent |
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*/ |
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inline bool checkEthernetFrame(const void *const data,const unsigned int len) const |
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{ |
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if (len < 32) |
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return true; |
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const uint8_t *const pp = reinterpret_cast<const uint8_t *>(data) + (len - 32); |
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const _ArItem *i = _history; |
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const _ArItem *const end = i + ZT_ANTIRECURSION_HISTORY_SIZE; |
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while (i != end) { |
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#ifdef ZT_NO_TYPE_PUNNING |
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if (!memcmp(pp,i->tail,32)) { |
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return false; |
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} |
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#else |
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const uint64_t *t = i->tail; |
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const uint64_t *p = reinterpret_cast<const uint64_t *>(pp); |
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uint64_t bits = *(t++) ^ *(p++); |
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bits |= *(t++) ^ *(p++); |
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bits |= *(t++) ^ *(p++); |
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bits |= *t ^ *p; |
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if (!bits) { |
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return false; |
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} |
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#endif |
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++i; |
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} |
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return true; |
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} |
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private: |
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struct _ArItem { uint64_t tail[4]; }; |
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_ArItem _history[ZT_ANTIRECURSION_HISTORY_SIZE]; |
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volatile unsigned long _ptr; |
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}; |
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} // namespace ZeroTier
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#endif |
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