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Huge convoluted logic de-tangling in multicast propagation, supernodes now do random propagation for more efficient coverage with less bias in sparse graph cases.

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This commit is contained in:
Adam Ierymenko
2013-08-21 11:45:06 -04:00
parent 1d9977b8b9
commit 2efc9b31bd
3 changed files with 168 additions and 84 deletions
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186
node/PacketDecoder.cpp
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@ -496,6 +496,24 @@ bool PacketDecoder::_doMULTICAST_FRAME(const RuntimeEnvironment *_r,const Shared
SharedPtr<Network> network(_r->nc->network(at<uint64_t>(ZT_PROTO_VERB_MULTICAST_FRAME_IDX_NETWORK_ID)));
if ((network)&&(network->isAllowed(source()))) {
Address originalSubmitterAddress(field(ZT_PROTO_VERB_MULTICAST_FRAME_IDX_SUBMITTER_ADDRESS,ZT_ADDRESS_LENGTH),ZT_ADDRESS_LENGTH);
if (originalSubmitterAddress.isReserved()) {
TRACE("dropped MULTICAST_FRAME from original submitter %s, received from %s(%s): invalid original submitter address",originalSubmitterAddress.toString().c_str(),source().toString().c_str(),_remoteAddress.toString().c_str());
return true;
}
if (originalSubmitterAddress == _r->identity.address()) {
TRACE("dropped MULTICAST_FRAME from original submitter %s, received from %s(%s): boomerang!",originalSubmitterAddress.toString().c_str(),source().toString().c_str(),_remoteAddress.toString().c_str());
return true;
}
SharedPtr<Peer> originalSubmitter(_r->topology->getPeer(originalSubmitterAddress));
if (!originalSubmitter) {
TRACE("requesting WHOIS on original multicast frame submitter %s",originalSubmitterAddress.toString().c_str());
_r->sw->requestWhois(originalSubmitterAddress);
_step = DECODE_WAITING_FOR_MULTICAST_FRAME_ORIGINAL_SENDER_LOOKUP;
return false; // try again if/when we get OK(WHOIS)
}
MAC fromMac(field(ZT_PROTO_VERB_MULTICAST_FRAME_IDX_SOURCE_MAC,6));
MulticastGroup mg(MAC(field(ZT_PROTO_VERB_MULTICAST_FRAME_IDX_DESTINATION_MAC,6)),at<uint32_t>(ZT_PROTO_VERB_MULTICAST_FRAME_IDX_ADI));
unsigned int hops = (*this)[ZT_PROTO_VERB_MULTICAST_FRAME_IDX_HOP_COUNT];
@ -504,94 +522,100 @@ bool PacketDecoder::_doMULTICAST_FRAME(const RuntimeEnvironment *_r,const Shared
unsigned int signaturelen = at<uint16_t>(ZT_PROTO_VERB_MULTICAST_FRAME_IDX_SIGNATURE_LENGTH);
unsigned char *dataAndSignature = field(ZT_PROTO_VERB_MULTICAST_FRAME_IDX_PAYLOAD,datalen + signaturelen);
if (!Multicaster::verifyMulticastPacket(originalSubmitter->identity(),network->id(),fromMac,mg,etherType,dataAndSignature,datalen,dataAndSignature + datalen,signaturelen)) {
LOG("dropped MULTICAST_FRAME from original submitter %s, received from %s(%s): FAILED SIGNATURE CHECK (spoofed original submitter?)",originalSubmitterAddress.toString().c_str(),source().toString().c_str(),_remoteAddress.toString().c_str());
return true;
}
if (++hops >= ZT_MULTICAST_PROPAGATION_DEPTH) {
TRACE("dropped MULTICAST_FRAME from original submitter %s, received from %s(%s): max depth reached",originalSubmitterAddress.toString().c_str(),source().toString().c_str(),_remoteAddress.toString().c_str());
return true;
}
uint64_t mccrc = Multicaster::computeMulticastDedupCrc(network->id(),fromMac,mg,etherType,dataAndSignature,datalen);
uint64_t now = Utils::now();
bool isDuplicate = _r->multicaster->checkDuplicate(mccrc,now);
if (originalSubmitterAddress == _r->identity.address()) {
// Technically should not happen, since the original submitter is
// excluded from consideration as a propagation recipient.
TRACE("dropped boomerang MULTICAST_FRAME received from %s(%s)",source().toString().c_str(),_remoteAddress.toString().c_str());
} else if ((!isDuplicate)||(_r->topology->amSupernode())) {
//
// If I am a supernode, I will repeatedly propagate duplicates. That's
// because supernodes are used to bridge sparse multicast groups. Non-
// supernodes will ignore duplicates completely.
//
// TODO: supernodes should keep a local bloom filter too and OR it with
// the bloom from the packet in order to pick different recipients each
// time a multicast returns to them for repropagation.
//
SharedPtr<Peer> originalSubmitter(_r->topology->getPeer(originalSubmitterAddress));
if (!originalSubmitter) {
TRACE("requesting WHOIS on original multicast frame submitter %s",originalSubmitterAddress.toString().c_str());
_r->sw->requestWhois(originalSubmitterAddress);
_step = DECODE_WAITING_FOR_MULTICAST_FRAME_ORIGINAL_SENDER_LOOKUP;
return false; // try again if/when we get OK(WHOIS)
} else if (Multicaster::verifyMulticastPacket(originalSubmitter->identity(),network->id(),fromMac,mg,etherType,dataAndSignature,datalen,dataAndSignature + datalen,signaturelen)) {
// In checking the multicast rate, we don't re-check if this is
// a duplicate. That's because if isDuplicate is true it means
// we're a supernode and it's a second pass relay.
if ((isDuplicate)||(network->multicastRateGate(originalSubmitter->address(),datalen))) {
_r->multicaster->addToDedupHistory(mccrc,now);
// Even if we are a supernode, we still don't repeatedly inject
// duplicates into our own tap.
if (!isDuplicate)
network->tap().put(fromMac,mg.mac(),etherType,dataAndSignature,datalen);
if (++hops < ZT_MULTICAST_PROPAGATION_DEPTH) {
Address upstream(source()); // save this since we mangle it
Multicaster::MulticastBloomFilter bloom(field(ZT_PROTO_VERB_MULTICAST_FRAME_IDX_BLOOM_FILTER,ZT_PROTO_VERB_MULTICAST_FRAME_BLOOM_FILTER_SIZE_BYTES));
SharedPtr<Peer> propPeers[ZT_MULTICAST_PROPAGATION_BREADTH];
unsigned int np = _r->multicaster->pickNextPropagationPeers(
*(_r->prng),
*(_r->topology),
network->id(),
mg,
originalSubmitterAddress,
upstream,
bloom,
ZT_MULTICAST_PROPAGATION_BREADTH,
propPeers,
now);
// In a bit of a hack, we re-use this packet to repeat it
// to our multicast propagation recipients. Afterwords we
// return true just to be sure this is the end of this
// packet's life cycle, since it is now mangled.
setSource(_r->identity.address());
(*this)[ZT_PROTO_VERB_MULTICAST_FRAME_IDX_HOP_COUNT] = hops;
memcpy(field(ZT_PROTO_VERB_MULTICAST_FRAME_IDX_BLOOM_FILTER,ZT_PROTO_VERB_MULTICAST_FRAME_BLOOM_FILTER_SIZE_BYTES),bloom.data(),ZT_PROTO_VERB_MULTICAST_FRAME_BLOOM_FILTER_SIZE_BYTES);
compress();
for(unsigned int i=0;i<np;++i) {
//TRACE("propagating multicast from original node %s: %s -> %s",originalSubmitterAddress.toString().c_str(),upstream.toString().c_str(),propPeers[i]->address().toString().c_str());
// Re-use this packet to re-send multicast frame to everyone
// downstream from us.
newInitializationVector();
setDestination(propPeers[i]->address());
_r->sw->send(*this,true);
}
// Return here just to be safe, since this packet's state is no
// longer valid.
return true;
} else {
//TRACE("terminating MULTICAST_FRAME propagation from %s(%s): max depth reached",source().toString().c_str(),_remoteAddress.toString().c_str());
}
} else {
LOG("dropped MULTICAST_FRAME from original sender %s: rate limit overrun",originalSubmitter->address().toString().c_str());
}
if (!isDuplicate) {
if (network->multicastRateGate(originalSubmitterAddress,datalen)) {
network->tap().put(fromMac,mg.mac(),etherType,dataAndSignature,datalen);
} else {
TRACE("rejected MULTICAST_FRAME forwarded by %s(%s): failed signature check (falsely claims origin %s)",source().toString().c_str(),_remoteAddress.toString().c_str(),originalSubmitterAddress.toString().c_str());
TRACE("dropped MULTICAST_FRAME from original submitter %s, received from %s(%s): sender rate limit exceeded",originalSubmitterAddress.toString().c_str(),source().toString().c_str(),_remoteAddress.toString().c_str());
return true;
}
} else {
TRACE("dropped duplicate MULTICAST_FRAME from %s(%s)",source().toString().c_str(),_remoteAddress.toString().c_str());
/* It's important that we do this *after* rate limit checking,
* otherwise supernodes could be used to execute a flood by
* first bouncing a multicast off a supernode and then flooding
* it with retransmits. */
_r->multicaster->addToDedupHistory(mccrc,now);
}
Address upstream(source()); // save this since we might mangle it below
Multicaster::MulticastBloomFilter bloom(field(ZT_PROTO_VERB_MULTICAST_FRAME_IDX_BLOOM_FILTER,ZT_PROTO_VERB_MULTICAST_FRAME_BLOOM_FILTER_SIZE_BYTES));
SharedPtr<Peer> propPeers[ZT_MULTICAST_PROPAGATION_BREADTH];
unsigned int np = 0;
if (_r->topology->amSupernode()) {
/* Supernodes behave differently here from ordinary nodes, as their
* role in the network is to bridge gaps between unconnected islands
* in a multicast propagation graph. Instead of using the ordinary
* multicast peer picker, supernodes propagate to random unvisited
* peers. They will also repeatedly propagate duplicate multicasts to
* new peers, while regular nodes simply discard them. This allows
* such gaps to be bridged more than once by ping-ponging off the
* same supernode -- a simple way to implement this without requiring
* that supernodes maintain a lot of state at the cost of a small
* amount of bandwidth. */
np = _r->multicaster->pickRandomPropagationPeers(
*(_r->prng),
*(_r->topology),
network->id(),
mg,
originalSubmitterAddress,
upstream,
bloom,
ZT_MULTICAST_PROPAGATION_BREADTH,
propPeers,
now);
} else if (isDuplicate) {
TRACE("dropped MULTICAST_FRAME from original submitter %s, received from %s(%s): duplicate",originalSubmitterAddress.toString().c_str(),source().toString().c_str(),_remoteAddress.toString().c_str());
return true;
} else {
/* Regular peers only propagate non-duplicate packets, and do so
* according to ordinary propagation priority rules. */
np = _r->multicaster->pickSocialPropagationPeers(
*(_r->prng),
*(_r->topology),
network->id(),
mg,
originalSubmitterAddress,
upstream,
bloom,
ZT_MULTICAST_PROPAGATION_BREADTH,
propPeers,
now);
}
/* Re-use *this* packet to repeat it to our propagation
* recipients, which invalidates its current contents and
* state. */
if (np) {
setSource(_r->identity.address());
(*this)[ZT_PROTO_VERB_MULTICAST_FRAME_IDX_HOP_COUNT] = hops;
memcpy(field(ZT_PROTO_VERB_MULTICAST_FRAME_IDX_BLOOM_FILTER,ZT_PROTO_VERB_MULTICAST_FRAME_BLOOM_FILTER_SIZE_BYTES),bloom.data(),ZT_PROTO_VERB_MULTICAST_FRAME_BLOOM_FILTER_SIZE_BYTES);
compress();
for(unsigned int i=0;i<np;++i) {
newInitializationVector();
setDestination(propPeers[i]->address());
_r->sw->send(*this,true);
}
}
/* Just to be safe, return true here to terminate processing as we
* have thoroughly destroyed our state by doing the above. */
return true;
} else {
TRACE("dropped MULTICAST_FRAME from %s(%s): network %.16llx unknown or sender not allowed",source().toString().c_str(),_remoteAddress.toString().c_str(),(unsigned long long)network->id());
}