mirror of
https://github.com/zerotier/ZeroTierOne.git
synced 2024-12-24 15:16:40 +00:00
245 lines
6.9 KiB
C++
245 lines
6.9 KiB
C++
/*
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* ZeroTier One - Global Peer to Peer Ethernet
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* Copyright (C) 2012-2013 ZeroTier Networks LLC
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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_MULTICASTER_HPP
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#define ZT_MULTICASTER_HPP
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#include <stdint.h>
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#include <string.h>
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#include <stdexcept>
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#include <map>
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#include <set>
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#include <list>
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#include <algorithm>
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#include "Constants.hpp"
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#include "Mutex.hpp"
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#include "MulticastGroup.hpp"
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#include "Address.hpp"
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#include "Buffer.hpp"
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namespace ZeroTier {
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/**
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* Multicast propagation algorithm core and database
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*/
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class Multicaster
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{
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public:
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Multicaster();
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~Multicaster();
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/**
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* Add or renew a peer's subscription to a multicast group
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*
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* @param nwid Network ID
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* @param a Address that LIKEd
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* @param mg Multicast group
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* @param now Current time
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*/
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void likesGroup(uint64_t nwid,const Address &a,const MulticastGroup &mg,uint64_t now);
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/**
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* Bring a peer closer in terms of propagation priority
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*
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* This gets called from PacketDecoder when a unicast frame is received.
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*
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* @param nwid Network ID
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* @param a Address to bring closer (e.g. due to unicast message)
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* @param now Current time
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*/
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void bringCloser(uint64_t nwid,const Address &a);
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/**
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* Erase entries for expired LIKEs and GOT records
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*/
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void clean();
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/**
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* Multicast deduplicator
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*
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* This checks to see if a multicast GUID has been seen before. If not, it
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* adds it to the history and returns false.
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*
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* @param nwid Network ID
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* @param mcGuid Multicast GUID (sender address + sender unique ID)
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* @return True if multicast IS a duplicate, false otherwise
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*/
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inline bool deduplicate(uint64_t nwid,uint64_t mcGuid)
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throw()
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{
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Mutex::Lock _l(_lock);
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_NetInfo &n = _nets[nwid];
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for(unsigned int i=0;i<ZT_MULTICAST_DEDUP_HISTORY_LENGTH;++i) {
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if (n.multicastHistory[i] == mcGuid)
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return true;
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}
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n.multicastHistory[n.multicastHistoryPtr++ % ZT_MULTICAST_DEDUP_HISTORY_LENGTH] = mcGuid;
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return false;
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}
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/**
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* Pick next hops for a multicast by proximity
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*
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* The function or function object must return true if more hops are desired
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* or false to stop finding new hops and return.
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*
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* @param nwid Network ID
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* @param mg Multicast group
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* @param nextHopFunc Function to call for each address, search stops if it returns false
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*/
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template<typename F>
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inline void getNextHops(uint64_t nwid,const MulticastGroup &mg,F nextHopFunc)
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{
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Mutex::Lock _l(_lock);
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std::map< uint64_t,_NetInfo >::iterator n(_nets.find(nwid));
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if (n == _nets.end())
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return;
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std::map< MulticastGroup,std::list< Address > >::iterator p(n->second.proximity.find(mg));
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if (p == n->second.proximity.end())
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return;
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for(std::list< Address >::iterator a(p->second.begin());a!=p->second.end();++a) {
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if (!nextHopFunc(*a))
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break;
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}
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}
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/**
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* Functor to add addresses to multicast frame propagation queues
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*
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* This function object checks the origin, bloom filter, and restriction
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* prefix for each address and if all these pass it adds the address and
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* increments the pointer pointed to by ptr. It stops (returns false) when
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* *ptr reaches end. It's used in PacketDecoder and Switch with getNextHops()
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* to compose multicast frame headers.
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*/
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class AddToPropagationQueue
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{
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public:
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/**
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* @param ptr Pointer to pointer to current position in queue
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* @param end End of queue
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* @param bloom Bloom filter field (must be 1024 bytes in length)
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* @param bloomNonce Random nonce for bloom filter randomization
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* @param origin Originating address
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* @param prefixBits Number of bits in propagation restriction prefix
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* @param prefix Propagation restrition prefix
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*/
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AddToPropagationQueue(unsigned char **ptr,unsigned char *end,unsigned char *bloom,uint16_t bloomNonce,const Address &origin,unsigned int prefixBits,unsigned int prefix)
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throw() :
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_origin(origin),
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_bloomNonce((uint64_t)bloomNonce),
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_prefixMask(0xffffffffffffffffULL >> (64 - prefixBits)),
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_prefix((uint64_t)prefix & _prefixMask),
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_ptr(ptr),
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_end(end),
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_bloom(bloom) {}
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inline bool operator()(const Address &a)
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throw()
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{
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// Exclude original sender -- obviously they've already seen it
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if (a == _origin)
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return true;
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// Exclude addresses not in this prefix domain
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if ((a.toInt() & _prefixMask) != _prefix)
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return true;
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// Exclude addresses remembered in bloom filter -- or else remember them
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uint64_t aint = a.toInt() + _bloomNonce;
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const unsigned int bit = (unsigned int)(aint ^ (aint >> 13) ^ (aint >> 26) ^ (aint >> 39)) & 0x1fff;
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unsigned char *const bbyte = _bloom + (bit >> 3); // note: bloom filter size == 1024 is hard-coded here
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const unsigned char bmask = 1 << (bit & 7);
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if ((*bbyte & bmask))
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return true;
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else *bbyte |= bmask;
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a.copyTo(*_ptr,ZT_ADDRESS_LENGTH);
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return ((*_ptr += ZT_ADDRESS_LENGTH) != _end);
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}
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private:
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const Address _origin;
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const uint64_t _bloomNonce;
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const uint64_t _prefixMask;
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const uint64_t _prefix;
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unsigned char **const _ptr;
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unsigned char *const _end;
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unsigned char *const _bloom;
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};
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private:
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// Information about a subscription
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struct _SubInfo
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{
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_SubInfo() :
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lastLike(0),
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proximitySlot() {}
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// Time of last MULTICAST_LIKE for this group
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uint64_t lastLike;
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// Slot in corresponding list in _proximity
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std::list< Address >::iterator proximitySlot;
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};
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// An address and multicast group tuple
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typedef std::pair< Address,MulticastGroup > _Subscription;
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// Multicast info for a given network
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struct _NetInfo
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{
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_NetInfo()
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throw()
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{
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memset(multicastHistory,0,sizeof(multicastHistory));
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multicastHistoryPtr = 0;
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}
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// Ring buffer of most recently injected multicast packet GUIDs
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uint64_t multicastHistory[ZT_MULTICAST_DEDUP_HISTORY_LENGTH];
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unsigned int multicastHistoryPtr;
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// Peer proximity ordering for peers subscribed to each group
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std::map< MulticastGroup,std::list< Address > > proximity;
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// Peer subscriptions to multicast groups
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std::map< _Subscription,_SubInfo > subscriptions;
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};
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std::map< uint64_t,_NetInfo > _nets;
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Mutex _lock;
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};
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} // namespace ZeroTier
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#endif
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