ZeroTierOne/node/Topology.cpp

338 lines
12 KiB
C++

/*
* ZeroTier One - Global Peer to Peer Ethernet
* Copyright (C) 2012-2013 ZeroTier Networks LLC
*
* 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 "Topology.hpp"
#include "NodeConfig.hpp"
namespace ZeroTier {
#define ZT_KISSDB_HASH_TABLE_SIZE 131072
#define ZT_KISSDB_KEY_SIZE ZT_ADDRESS_LENGTH
#define ZT_KISSDB_VALUE_SIZE ZT_PEER_MAX_SERIALIZED_LENGTH
Topology::Topology(const RuntimeEnvironment *renv,const char *dbpath)
throw(std::runtime_error) :
Thread(),
_r(renv)
{
if (KISSDB_open(&_dbm,dbpath,KISSDB_OPEN_MODE_RWCREAT,ZT_KISSDB_HASH_TABLE_SIZE,ZT_KISSDB_KEY_SIZE,ZT_KISSDB_VALUE_SIZE)) {
if (KISSDB_open(&_dbm,dbpath,KISSDB_OPEN_MODE_RWREPLACE,ZT_KISSDB_HASH_TABLE_SIZE,ZT_KISSDB_KEY_SIZE,ZT_KISSDB_VALUE_SIZE))
throw std::runtime_error("unable to open peer database (rw/create)");
}
if ((_dbm.key_size != ZT_KISSDB_KEY_SIZE)||(_dbm.value_size != ZT_KISSDB_VALUE_SIZE)||(_dbm.hash_table_size != ZT_KISSDB_HASH_TABLE_SIZE)) {
KISSDB_close(&_dbm);
if (KISSDB_open(&_dbm,dbpath,KISSDB_OPEN_MODE_RWREPLACE,ZT_KISSDB_HASH_TABLE_SIZE,ZT_KISSDB_KEY_SIZE,ZT_KISSDB_VALUE_SIZE))
throw std::runtime_error("unable to open peer database (recreate)");
}
Utils::lockDownFile(dbpath,false); // node.db caches secrets
start();
}
Topology::~Topology()
{
{
Mutex::Lock _l(_peerDeepVerifyJobs_m);
_peerDeepVerifyJobs.push_back(_PeerDeepVerifyJob());
_peerDeepVerifyJobs.back().type = _PeerDeepVerifyJob::CLEAN_CACHE;
_peerDeepVerifyJobs.push_back(_PeerDeepVerifyJob());
_peerDeepVerifyJobs.back().type = _PeerDeepVerifyJob::EXIT_THREAD;
}
_peerDeepVerifyJobs_c.signal();
while (running())
Thread::sleep(10); // wait for thread to terminate without join()
KISSDB_close(&_dbm);
}
void Topology::setSupernodes(const std::map< Identity,std::vector<InetAddress> > &sn)
{
Mutex::Lock _l(_supernodes_m);
_supernodes = sn;
_supernodeAddresses.clear();
_supernodePeers.clear();
for(std::map< Identity,std::vector<InetAddress> >::const_iterator i(sn.begin());i!=sn.end();++i) {
if (i->first != _r->identity) {
SharedPtr<Peer> p(getPeer(i->first.address()));
if ((!p)||(p->identity() != i->first)) {
p = SharedPtr<Peer>(new Peer(_r->identity,i->first));
_reallyAddPeer(p);
}
for(std::vector<InetAddress>::const_iterator j(i->second.begin());j!=i->second.end();++j)
p->setPathAddress(*j,true);
_supernodePeers.push_back(p);
}
_supernodeAddresses.insert(i->first.address());
}
}
void Topology::addPeer(const SharedPtr<Peer> &candidate,void (*callback)(void *,const SharedPtr<Peer> &,Topology::PeerVerifyResult),void *arg)
{
if (candidate->address() != _r->identity.address()) {
Mutex::Lock _l(_peerDeepVerifyJobs_m);
_peerDeepVerifyJobs.push_back(_PeerDeepVerifyJob());
_PeerDeepVerifyJob &job = _peerDeepVerifyJobs.back();
job.callback = callback;
job.arg = arg;
job.candidate = candidate;
job.type = _PeerDeepVerifyJob::VERIFY_PEER;
_peerDeepVerifyJobs_c.signal();
} else {
TRACE("BUG: addPeer() caught and ignored attempt to add peer for self");
if (callback)
callback(arg,candidate,PEER_VERIFY_REJECTED_DUPLICATE_TRIAGED);
}
}
SharedPtr<Peer> Topology::getPeer(const Address &zta)
{
if (zta == _r->identity.address()) {
TRACE("BUG: ignored attempt to getPeer() for self, returned NULL");
return SharedPtr<Peer>();
}
{
Mutex::Lock _l(_activePeers_m);
std::map< Address,SharedPtr<Peer> >::const_iterator ap(_activePeers.find(zta));
if ((ap != _activePeers.end())&&(ap->second))
return ap->second;
}
Buffer<ZT_KISSDB_VALUE_SIZE> b(ZT_KISSDB_VALUE_SIZE);
_dbm_m.lock();
if (!KISSDB_get(&_dbm,zta.data(),b.data())) {
_dbm_m.unlock();
SharedPtr<Peer> p(new Peer());
try {
p->deserialize(b,0);
Mutex::Lock _l(_activePeers_m);
_activePeers[zta] = p;
return p;
} catch ( ... ) {
TRACE("unexpected exception deserializing peer %s from peerdb",zta.toString().c_str());
return SharedPtr<Peer>();
}
} else _dbm_m.unlock();
return SharedPtr<Peer>();
}
SharedPtr<Peer> Topology::getBestSupernode(const Address *avoid,unsigned int avoidCount) const
{
SharedPtr<Peer> bestSupernode;
unsigned long bestSupernodeLatency = 0xffff;
uint64_t now = Utils::now();
Mutex::Lock _l(_supernodes_m);
for(std::vector< SharedPtr<Peer> >::const_iterator sn=_supernodePeers.begin();sn!=_supernodePeers.end();) {
for(unsigned int i=0;i<avoidCount;++i) {
if (avoid[i] == (*sn)->address())
goto skip_and_try_next_supernode;
}
if ((*sn)->hasActiveDirectPath(now)) { // only consider those that responded to pings
unsigned int l = (*sn)->latency();
if ((l)&&(l <= bestSupernodeLatency)) {
bestSupernodeLatency = l;
bestSupernode = *sn;
}
}
skip_and_try_next_supernode:
++sn;
}
if (bestSupernode)
return bestSupernode;
for(std::vector< SharedPtr<Peer> >::const_iterator sn=_supernodePeers.begin();sn!=_supernodePeers.end();++sn) {
if ((*sn)->hasActiveDirectPath(now)) { // only consider those that responded to pings
unsigned int l = (*sn)->latency();
if ((l)&&(l <= bestSupernodeLatency)) {
bestSupernodeLatency = l;
bestSupernode = *sn;
}
}
}
if (bestSupernode)
return bestSupernode;
uint64_t bestSupernodeLastDirectReceive = 0;
for(std::vector< SharedPtr<Peer> >::const_iterator sn=_supernodePeers.begin();sn!=_supernodePeers.end();++sn) {
uint64_t l = (*sn)->lastDirectReceive();
if (l > bestSupernodeLastDirectReceive) {
bestSupernodeLastDirectReceive = l;
bestSupernode = *sn;
}
}
return bestSupernode;
}
void Topology::clean()
{
{
Mutex::Lock _l(_peerDeepVerifyJobs_m);
_peerDeepVerifyJobs.push_back(_PeerDeepVerifyJob());
_peerDeepVerifyJobs.back().type = _PeerDeepVerifyJob::CLEAN_CACHE;
}
_peerDeepVerifyJobs_c.signal();
}
void Topology::main()
throw()
{
for(;;) {
_peerDeepVerifyJobs_m.lock();
if (_peerDeepVerifyJobs.empty()) {
_peerDeepVerifyJobs_m.unlock();
_peerDeepVerifyJobs_c.wait();
continue;
}
_PeerDeepVerifyJob job(_peerDeepVerifyJobs.front());
_peerDeepVerifyJobs.pop_front();
unsigned long queueRemaining = _peerDeepVerifyJobs.size();
_peerDeepVerifyJobs_m.unlock();
switch(job.type) {
case _PeerDeepVerifyJob::VERIFY_PEER:
/* TODO: We should really verify peers every time completely if this
* is a supernode, perhaps deferring the expensive part for new
* addresses. An attempt at claim jumping should also trigger a
* short duration ban of the originating IP address in most cases,
* since this means either malicious intent or broken software. */
TRACE("verifying peer: %s",job.candidate->identity().address().toString().c_str());
if ((job.candidate->identity())&&(!job.candidate->identity().address().isReserved())&&(job.candidate->identity().locallyValidate(false))) {
// Peer passes sniff test, so check to see if we've already got
// one with the same address.
SharedPtr<Peer> existingPeer(getPeer(job.candidate->identity().address()));
if (existingPeer) {
if (existingPeer->identity() == job.candidate->identity()) {
// It's an *exact* duplicate, so return the existing peer
if (job.callback)
job.callback(job.arg,existingPeer,PEER_VERIFY_ACCEPTED_ALREADY_HAVE);
} else if (queueRemaining > 3) {
/* Prevents a CPU hog DOS attack, while allowing a very unlikely kind of
* DOS attack where someone knows someone else's address prior to their
* registering it and claim-jumps them and then floods with bad identities
* to hold their claim. Of the two, the latter would be infeasable
* without already having cracked the target's machine in which case
* the attacker has their private key anyway and can really steal their
* identity. So why bother.*/
TRACE("%s is duplicate, load too high, old won",job.candidate->identity().address().toString().c_str());
if (job.callback)
job.callback(job.arg,job.candidate,PEER_VERIFY_REJECTED_DUPLICATE_TRIAGED);
} else {
// It's different so deeply validate it first, then the
// existing claimant, and toss the imposter. If both verify, the
// one we already have wins.
if (!job.candidate->identity().locallyValidate(true)) {
LOG("Topology: IMPOSTER %s rejected",job.candidate->identity().address().toString().c_str());
if (job.callback)
job.callback(job.arg,job.candidate,PEER_VERIFY_REJECTED_INVALID_IDENTITY);
} else if (!existingPeer->identity().locallyValidate(true)) {
LOG("Topology: previous IMPOSTER %s displaced by valid identity!",job.candidate->identity().address().toString().c_str());
_reallyAddPeer(job.candidate);
if (job.callback)
job.callback(job.arg,job.candidate,PEER_VERIFY_ACCEPTED_DISPLACED_INVALID_ADDRESS);
} else {
LOG("Topology: tie between apparently valid claims on %s, oldest won",job.candidate->identity().address().toString().c_str());
if (job.callback)
job.callback(job.arg,job.candidate,PEER_VERIFY_REJECTED_DUPLICATE);
}
}
} else {
TRACE("%s accepted as new",job.candidate->identity().address().toString().c_str());
_reallyAddPeer(job.candidate);
if (job.callback)
job.callback(job.arg,job.candidate,PEER_VERIFY_ACCEPTED_NEW);
}
} else {
TRACE("%s rejected, identity failed initial checks",job.candidate->identity().address().toString().c_str());
if (job.callback)
job.callback(job.arg,job.candidate,PEER_VERIFY_REJECTED_INVALID_IDENTITY);
}
break;
case _PeerDeepVerifyJob::CLEAN_CACHE:
TRACE("cleaning caches and flushing modified peers to disk...");
{
Mutex::Lock _l(_activePeers_m);
for(std::map< Address,SharedPtr<Peer> >::iterator p(_activePeers.begin());p!=_activePeers.end();++p) {
if (p->second->getAndResetDirty()) {
try {
Buffer<ZT_PEER_MAX_SERIALIZED_LENGTH> b;
p->second->serialize(b);
b.zeroUnused();
_dbm_m.lock();
if (KISSDB_put(&_dbm,p->second->identity().address().data(),b.data())) {
TRACE("error writing %s to peer.db",p->second->identity().address().toString().c_str());
}
_dbm_m.unlock();
} catch ( ... ) {
TRACE("unexpected exception flushing %s to peer.db",p->second->identity().address().toString().c_str());
}
}
}
}
break;
case _PeerDeepVerifyJob::EXIT_THREAD:
TRACE("thread terminating...");
return;
}
}
}
void Topology::_reallyAddPeer(const SharedPtr<Peer> &p)
{
{
Mutex::Lock _l(_activePeers_m);
_activePeers[p->identity().address()] = p;
}
try {
Buffer<ZT_PEER_MAX_SERIALIZED_LENGTH> b;
p->serialize(b);
b.zeroUnused();
_dbm_m.lock();
if (KISSDB_put(&_dbm,p->identity().address().data(),b.data())) {
TRACE("error writing %s to peerdb",p->address().toString().c_str());
} else p->getAndResetDirty();
_dbm_m.unlock();
} catch ( ... ) {
TRACE("unexpected exception flushing to peerdb");
}
}
} // namespace ZeroTier