ExternalVendorCode/ZeroTierOne
1
0
Fork 0
mirror of https://github.com/zerotier/ZeroTierOne.git synced 2024-12-19 04:57:53 +00:00
Code Issues Actions Packages Projects Releases Wiki Activity

docs

Browse Source
This commit is contained in:
Adam Ierymenko 2013-12-22 10:56:03 -08:00
parent fe6b7f477c
commit 026442f28f
1 changed files with 44 additions and 18 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

62
node/PacketDecoder.cpp
View File

@ -452,39 +452,61 @@ bool PacketDecoder::_doMULTICAST_FRAME(const RuntimeEnvironment *_r,const Shared
SharedPtr<Network> network(_r->nc->network(nwid));
// Grab, verify, and learn certificate if any -- provided we are a member of this network
// Note: we can do this before verification of the actual packet, since the certificate
// has its own separate signature.
/* Grab, verify, and learn certificate of network membership if any -- provided we are
* a member of this network. Note: we can do this before verification of the actual
* packet, since the certificate has its own separate signature. In other words a valid
* COM does not imply a valid multicast; they are two separate things. The ability to
* include the COM with the multicast is a performance optimization to allow peers to
* distribute their COM along with their packets instead of as a separate transaction.
* This causes network memberships to start working faster. */
if (((flags & ZT_PROTO_VERB_MULTICAST_FRAME_FLAGS_HAS_MEMBERSHIP_CERTIFICATE))&&(network)) {
CertificateOfMembership originCom(*this,ZT_PROTO_VERB_MULTICAST_FRAME_IDX_FRAME + frameLen + 2 + signatureLen);
Address signedBy(originCom.signedBy());
if ((originCom.networkId() == nwid)&&(signedBy == network->controller())) {
SharedPtr<Peer> signingPeer(_r->topology->getPeer(signedBy));
if (!signingPeer) {
// Technically this shouldn't happen, but handle it anyway...
_r->sw->requestWhois(signedBy);
Address comSignedBy(originCom.signedBy());
if ((originCom.networkId() == nwid)&&(comSignedBy == network->controller())) {
SharedPtr<Peer> comSigningPeer(_r->topology->getPeer(comSignedBy));
if (!comSigningPeer) {
// Technically this should never happen because the COM should be signed by
// the master for this network (in current usage) and we ought to already have
// that cached. But handle it anyway.
_r->sw->requestWhois(comSignedBy);
_step = DECODE_WAITING_FOR_MULTICAST_FRAME_ORIGINAL_SENDER_LOOKUP; // causes processing to come back here
return false;
} else if (originCom.verify(signingPeer->identity())) {
} else if (originCom.verify(comSigningPeer->identity())) {
// The certificate is valid so learn it. As explained above this does not
// imply validation of the multicast. That happens later. Look for a call
// to network->isAllowed().
network->addMembershipCertificate(originCom);
} else {
// Go ahead and drop the multicast though if the COM was invalid, since this
// obviously signifies a problem.
LOG("dropped MULTICAST_FRAME from %s(%s): included COM failed authentication check",source().toString().c_str(),_remoteAddress.toString().c_str());
return true;
}
} else {
// Go ahead and drop the multicast here too, since this also ought never to
// happen and certainly indicates a problem.
LOG("dropped MULTICAST_FRAME from %s(%s): included COM is not for this network",source().toString().c_str(),_remoteAddress.toString().c_str());
return true;
}
}
// Check multicast signature to verify original sender
// Check the multicast frame's signature to verify that its original sender is
// who it claims to be.
const unsigned int signedPartLen = (ZT_PROTO_VERB_MULTICAST_FRAME_IDX_FRAME - ZT_PROTO_VERB_MULTICAST_FRAME_IDX__START_OF_SIGNED_PORTION) + frameLen;
if (!originPeer->identity().verify(field(ZT_PROTO_VERB_MULTICAST_FRAME_IDX__START_OF_SIGNED_PORTION,signedPartLen),signedPartLen,signature,signatureLen)) {
TRACE("dropped MULTICAST_FRAME from %s(%s): failed signature verification, claims to be from %s",source().toString().c_str(),_remoteAddress.toString().c_str(),origin.toString().c_str());
LOG("dropped MULTICAST_FRAME from %s(%s): failed signature verification, claims to be from %s",source().toString().c_str(),_remoteAddress.toString().c_str(),origin.toString().c_str());
return true;
}
// Security check to prohibit multicasts that are really Ethernet unicasts
// Security check to prohibit multicasts that are really Ethernet unicasts...
// otherwise people could do weird things like multicast out a TCP SYN.
if (!dest.mac().isMulticast()) {
TRACE("dropped MULTICAST_FRAME from %s(%s): %s is not a multicast/broadcast address",source().toString().c_str(),_remoteAddress.toString().c_str(),dest.mac().toString().c_str());
LOG("dropped MULTICAST_FRAME from %s(%s): %s is not a multicast/broadcast address",source().toString().c_str(),_remoteAddress.toString().c_str(),dest.mac().toString().c_str());
return true;
}
#ifdef ZT_TRACE_MULTICAST
// This code, if enabled, sends a UDP pingback to a logger for each multicast.
char mct[1024],mctdepth[1024];
unsigned int startingFifoItems = 0;
for(unsigned int i=0;i<ZT_PROTO_VERB_MULTICAST_FRAME_LEN_PROPAGATION_FIFO;i+=ZT_ADDRESS_LENGTH) {
@ -510,12 +532,13 @@ bool PacketDecoder::_doMULTICAST_FRAME(const RuntimeEnvironment *_r,const Shared
_r->demarc->send(Demarc::ANY_PORT,ZT_DEFAULTS.multicastTraceWatcher,mct,strlen(mct),-1);
#endif
// This gets updated later in most cases but start with the global limit.
unsigned int maxDepth = ZT_MULTICAST_GLOBAL_MAX_DEPTH;
if ((origin == _r->identity.address())||(_r->mc->deduplicate(nwid,guid))) {
// Ordinary nodes will drop duplicates. Supernodes keep propagating
// them since they're used as hubs to link disparate clusters of
// members of the same multicast group.
// This is a boomerang or a duplicate of a multicast we've already seen. Ordinary
// nodes drop these, while supernodes will keep propagating them since they can
// act as bridges between sparse multicast networks more than once.
if (!_r->topology->amSupernode()) {
#ifdef ZT_TRACE_MULTICAST
Utils::snprintf(mct,sizeof(mct),
@ -646,6 +669,8 @@ bool PacketDecoder::_doMULTICAST_FRAME(const RuntimeEnvironment *_r,const Shared
TRACE("not forwarding MULTICAST_FRAME from %s(%s): max propagation depth reached",source().toString().c_str(),_remoteAddress.toString().c_str());
return true;
}
// Update depth in packet with new incremented value
setAt(ZT_PROTO_VERB_MULTICAST_FRAME_IDX_PROPAGATION_DEPTH,(uint16_t)depth);
// New FIFO with room for one extra, since head will be next hop
@ -676,7 +701,8 @@ bool PacketDecoder::_doMULTICAST_FRAME(const RuntimeEnvironment *_r,const Shared
unsigned int numAdded = (unsigned int)(newFifoPtr - beforeAdd) / ZT_ADDRESS_LENGTH;
#endif
// Zero-terminate new FIFO if not completely full
// Zero-terminate new FIFO if not completely full. We pad the remainder with
// zeroes because this improves data compression ratios.
while (newFifoPtr != newFifoEnd)
*(newFifoPtr++) = (unsigned char)0;