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/*
* ZeroTier One - Network Virtualization Everywhere
* Copyright (C) 2011-2015 ZeroTier, Inc.
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*
* --
*
* ZeroTier may be used and distributed under the terms of the GPLv3, which
* are available at: http://www.gnu.org/licenses/gpl-3.0.html
*
* If you would like to embed ZeroTier into a commercial application or
* redistribute it in a modified binary form, please contact ZeroTier Networks
* LLC. Start here: http://www.zerotier.com/
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "Constants.hpp"
#include "SelfAwareness.hpp"
#include "RuntimeEnvironment.hpp"
#include "Node.hpp"
#include "Topology.hpp"
#include "Packet.hpp"
#include "Peer.hpp"
namespace ZeroTier {
class _ResetWithinScope
{
public:
_ResetWithinScope(const RuntimeEnvironment *renv,uint64_t now,InetAddress::IpScope scope) :
RR(renv),
_now(now),
_scope(scope) {}
inline void operator()(Topology &t,const SharedPtr<Peer> &p)
{
if (p->resetWithinScope(RR,_scope,_now))
peersReset.push_back(p);
}
std::vector< SharedPtr<Peer> > peersReset;
private:
const RuntimeEnvironment *RR;
uint64_t _now;
InetAddress::IpScope _scope;
};
SelfAwareness::SelfAwareness(const RuntimeEnvironment *renv) :
RR(renv)
{
memset(_lastPhysicalAddress,0,sizeof(_lastPhysicalAddress));
}
SelfAwareness::~SelfAwareness()
{
}
void SelfAwareness::iam(const Address &reporter,const InetAddress &reporterPhysicalAddress,const InetAddress &myPhysicalAddress,bool trusted)
{
// This code depends on the numeric values assigned to scopes in InetAddress.hpp
const unsigned int scope = (unsigned int)myPhysicalAddress.ipScope();
if ((scope > 0)&&(scope < (unsigned int)InetAddress::IP_SCOPE_LOOPBACK)) {
if ( (!trusted) && ((scope == (unsigned int)InetAddress::IP_SCOPE_GLOBAL)||(scope != (unsigned int)reporterPhysicalAddress.ipScope())) ) {
/* For now only trusted peers are permitted to inform us of changes to
* our global Internet IP or to changes of NATed IPs. We'll let peers on
* private, shared, or link-local networks inform us of changes as long
* as they too are at the same scope. This discrimination avoids a DoS
* attack in which an attacker could force us to reset our connections. */
return;
} else {
Mutex::Lock _l(_lock);
InetAddress &lastPhy = _lastPhysicalAddress[scope - 1];
if (!lastPhy) {
TRACE("learned physical address %s for scope %u from reporter %s(%s) (replaced <null>)",myPhysicalAddress.toString().c_str(),scope,reporter.toString().c_str(),reporterPhysicalAddress.toString().c_str());
lastPhy = myPhysicalAddress;
} else if (lastPhy != myPhysicalAddress) {
TRACE("learned physical address %s for scope %u from reporter %s(%s) (replaced %s, resetting within scope)",myPhysicalAddress.toString().c_str(),scope,reporter.toString().c_str(),reporterPhysicalAddress.toString().c_str(),lastPhy.toString().c_str());
lastPhy = myPhysicalAddress;
uint64_t now = RR->node->now();
_ResetWithinScope rset(RR,now,(InetAddress::IpScope)scope);
RR->topology->eachPeer<_ResetWithinScope &>(rset);
// For all peers for whom we forgot an address, send a packet indirectly if
// they are still considered alive so that we will re-establish direct links.
SharedPtr<Peer> sn(RR->topology->getBestSupernode());
if (sn) {
Path *snp = sn->getBestPath(now);
if (snp) {
for(std::vector< SharedPtr<Peer> >::const_iterator p(rset.peersReset.begin());p!=rset.peersReset.end();++p) {
if ((*p)->alive(now)) {
TRACE("sending indirect NOP to %s via %s(%s) to re-establish link",(*p)->address().toString().c_str(),sn->address().toString().c_str(),snp->address().toString().c_str());
Packet outp((*p)->address(),RR->identity.address(),Packet::VERB_NOP);
outp.armor((*p)->key(),true);
snp->send(RR,outp.data(),outp.size(),now);
}
}
}
}
}
}
}
}
} // namespace ZeroTier
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