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Probable fix for GitHub issue #63 - do not unite() if either path is TCP, since doing so can result in asymmetric failed NAT-t over UDP if one side has a firewall that permits outgoing UDP but not incoming.

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This commit is contained in:
Adam Ierymenko 2014-04-10 11:17:54 -07:00
parent 119ef5ecbf
commit b117ff5435
6 changed files with 39 additions and 19 deletions
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21
node/Switch.cpp
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@ -560,7 +560,7 @@ void Switch::_handleRemotePacketFragment(const SharedPtr<Socket> &fromSock,const
fragment.incrementHops();
SharedPtr<Peer> relayTo = _r->topology->getPeer(destination);
if ((!relayTo)||(!relayTo->send(_r,fragment.data(),fragment.size(),Utils::now()))) {
if ((!relayTo)||(relayTo->send(_r,fragment.data(),fragment.size(),Utils::now()) == Path::PATH_TYPE_NULL)) {
relayTo = _r->topology->getBestSupernode();
if (relayTo)
relayTo->send(_r,fragment.data(),fragment.size(),Utils::now());
@ -633,10 +633,13 @@ void Switch::_handleRemotePacketHead(const SharedPtr<Socket> &fromSock,const Ine
packet->incrementHops();
SharedPtr<Peer> relayTo = _r->topology->getPeer(destination);
if ((relayTo)&&(relayTo->send(_r,packet->data(),packet->size(),Utils::now()))) {
// If we've relayed, this periodically tries to get them to
// talk directly to save our bandwidth.
unite(source,destination,false);
Path::Type relayedVia;
if ((relayTo)&&((relayedVia = relayTo->send(_r,packet->data(),packet->size(),Utils::now())) != Path::PATH_TYPE_NULL)) {
/* If both paths are UDP, attempt to invoke UDP NAT-t between peers
* by sending VERB_RENDEZVOUS. Do not do this for TCP due to GitHub
* issue #63. */
if ((fromSock->udp())&&(relayedVia == Path::PATH_TYPE_UDP))
unite(source,destination,false);
} else {
// If we've received a packet not for us and we don't have
// a direct path to its recipient, pass it to (another)
@ -702,7 +705,7 @@ Address Switch::_sendWhoisRequest(const Address &addr,const Address *peersAlread
addr.appendTo(outp);
outp.armor(supernode->key(),true);
uint64_t now = Utils::now();
if (supernode->send(_r,outp.data(),outp.size(),now))
if (supernode->send(_r,outp.data(),outp.size(),now) != Path::PATH_TYPE_NULL)
return supernode->address();
}
return Address();
@ -731,7 +734,7 @@ bool Switch::_trySend(const Packet &packet,bool encrypt)
tmp.armor(peer->key(),encrypt);
if (via->send(_r,tmp.data(),chunkSize,now)) {
if (via->send(_r,tmp.data(),chunkSize,now) != Path::PATH_TYPE_NULL) {
if (chunkSize < tmp.size()) {
// Too big for one bite, fragment the rest
unsigned int fragStart = chunkSize;
@ -744,9 +747,7 @@ bool Switch::_trySend(const Packet &packet,bool encrypt)
for(unsigned int f=0;f<fragsRemaining;++f) {
chunkSize = std::min(remaining,(unsigned int)(ZT_UDP_DEFAULT_PAYLOAD_MTU - ZT_PROTO_MIN_FRAGMENT_LENGTH));
Packet::Fragment frag(tmp,fragStart,chunkSize,f + 1,totalFragments);
if (!via->send(_r,frag.data(),frag.size(),now)) {
TRACE("WARNING: packet send to %s failed on later fragment #%u (check IP layer buffer sizes?)",via->address().toString().c_str(),f + 1);
}
via->send(_r,frag.data(),frag.size(),now);
fragStart += chunkSize;
remaining -= chunkSize;
}