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ZeroTierOne/node/Switch.cpp

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/*
* ZeroTier One - Network Virtualization Everywhere
* Copyright (C) 2011-2016 ZeroTier, Inc. https://www.zerotier.com/
*
* 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/>.
*/
#include <stdio.h>
#include <stdlib.h>
#include <algorithm>
#include <utility>
#include <stdexcept>
#include "../version.h"
#include "../include/ZeroTierOne.h"
#include "Constants.hpp"
#include "RuntimeEnvironment.hpp"
#include "Switch.hpp"
#include "Node.hpp"
#include "InetAddress.hpp"
#include "Topology.hpp"
#include "Peer.hpp"
#include "SelfAwareness.hpp"
#include "Packet.hpp"
#include "Cluster.hpp"
namespace ZeroTier {
#ifdef ZT_TRACE
static const char *etherTypeName(const unsigned int etherType)
{
switch(etherType) {
case ZT_ETHERTYPE_IPV4: return "IPV4";
case ZT_ETHERTYPE_ARP: return "ARP";
case ZT_ETHERTYPE_RARP: return "RARP";
case ZT_ETHERTYPE_ATALK: return "ATALK";
case ZT_ETHERTYPE_AARP: return "AARP";
case ZT_ETHERTYPE_IPX_A: return "IPX_A";
case ZT_ETHERTYPE_IPX_B: return "IPX_B";
case ZT_ETHERTYPE_IPV6: return "IPV6";
}
return "UNKNOWN";
}
#endif // ZT_TRACE
Switch::Switch(const RuntimeEnvironment *renv) :
RR(renv),
_lastBeaconResponse(0),
_outstandingWhoisRequests(32),
_lastUniteAttempt(8) // only really used on root servers and upstreams, and it'll grow there just fine
{
}
Switch::~Switch()
{
}
void Switch::onRemotePacket(const InetAddress &localAddr,const InetAddress &fromAddr,const void *data,unsigned int len)
{
try {
const uint64_t now = RR->node->now();
if (len == 13) {
/* LEGACY: before VERB_PUSH_DIRECT_PATHS, peers used broadcast
* announcements on the LAN to solve the 'same network problem.' We
* no longer send these, but we'll listen for them for a while to
* locate peers with versions <1.0.4. */
Address beaconAddr(reinterpret_cast<const char *>(data) + 8,5);
if (beaconAddr == RR->identity.address())
return;
if (!RR->node->shouldUsePathForZeroTierTraffic(localAddr,fromAddr))
return;
SharedPtr<Peer> peer(RR->topology->getPeer(beaconAddr));
if (peer) { // we'll only respond to beacons from known peers
if ((now - _lastBeaconResponse) >= 2500) { // limit rate of responses
_lastBeaconResponse = now;
Packet outp(peer->address(),RR->identity.address(),Packet::VERB_NOP);
outp.armor(peer->key(),true);
RR->node->putPacket(localAddr,fromAddr,outp.data(),outp.size());
}
}
} else if (len > ZT_PROTO_MIN_FRAGMENT_LENGTH) { // min length check is important!
if (reinterpret_cast<const uint8_t *>(data)[ZT_PACKET_FRAGMENT_IDX_FRAGMENT_INDICATOR] == ZT_PACKET_FRAGMENT_INDICATOR) {
// Handle fragment ----------------------------------------------------
Packet::Fragment fragment(data,len);
const Address destination(fragment.destination());
if (destination != RR->identity.address()) {
// Fragment is not for us, so try to relay it
if (fragment.hops() < ZT_RELAY_MAX_HOPS) {
fragment.incrementHops();
// Note: we don't bother initiating NAT-t for fragments, since heads will set that off.
// It wouldn't hurt anything, just redundant and unnecessary.
SharedPtr<Peer> relayTo = RR->topology->getPeer(destination);
if ((!relayTo)||(!relayTo->send(fragment.data(),fragment.size(),now))) {
#ifdef ZT_ENABLE_CLUSTER
if (RR->cluster) {
RR->cluster->sendViaCluster(Address(),destination,fragment.data(),fragment.size(),false);
return;
}
#endif
// Don't know peer or no direct path -- so relay via root server
relayTo = RR->topology->getBestRoot();
if (relayTo)
relayTo->send(fragment.data(),fragment.size(),now);
}
} else {
TRACE("dropped relay [fragment](%s) -> %s, max hops exceeded",fromAddr.toString().c_str(),destination.toString().c_str());
}
} else {
// Fragment looks like ours
const uint64_t fragmentPacketId = fragment.packetId();
const unsigned int fragmentNumber = fragment.fragmentNumber();
const unsigned int totalFragments = fragment.totalFragments();
if ((totalFragments <= ZT_MAX_PACKET_FRAGMENTS)&&(fragmentNumber < ZT_MAX_PACKET_FRAGMENTS)&&(fragmentNumber > 0)&&(totalFragments > 1)) {
// Fragment appears basically sane. Its fragment number must be
// 1 or more, since a Packet with fragmented bit set is fragment 0.
// Total fragments must be more than 1, otherwise why are we
// seeing a Packet::Fragment?
Mutex::Lock _l(_rxQueue_m);
RXQueueEntry *const rq = _findRXQueueEntry(now,fragmentPacketId);
if ((!rq->timestamp)||(rq->packetId != fragmentPacketId)) {
// No packet found, so we received a fragment without its head.
//TRACE("fragment (%u/%u) of %.16llx from %s",fragmentNumber + 1,totalFragments,fragmentPacketId,fromAddr.toString().c_str());
rq->timestamp = now;
rq->packetId = fragmentPacketId;
rq->frags[fragmentNumber - 1] = fragment;
rq->totalFragments = totalFragments; // total fragment count is known
rq->haveFragments = 1 << fragmentNumber; // we have only this fragment
rq->complete = false;
} else if (!(rq->haveFragments & (1 << fragmentNumber))) {
// We have other fragments and maybe the head, so add this one and check
//TRACE("fragment (%u/%u) of %.16llx from %s",fragmentNumber + 1,totalFragments,fragmentPacketId,fromAddr.toString().c_str());
rq->frags[fragmentNumber - 1] = fragment;
rq->totalFragments = totalFragments;
if (Utils::countBits(rq->haveFragments |= (1 << fragmentNumber)) == totalFragments) {
// We have all fragments -- assemble and process full Packet
//TRACE("packet %.16llx is complete, assembling and processing...",fragmentPacketId);
for(unsigned int f=1;f<totalFragments;++f)
rq->frag0.append(rq->frags[f - 1].payload(),rq->frags[f - 1].payloadLength());
if (rq->frag0.tryDecode(RR,false)) {
rq->timestamp = 0; // packet decoded, free entry
} else {
rq->complete = true; // set complete flag but leave entry since it probably needs WHOIS or something
}
}
} // else this is a duplicate fragment, ignore
}
}
// --------------------------------------------------------------------
} else if (len >= ZT_PROTO_MIN_PACKET_LENGTH) { // min length check is important!
// Handle packet head -------------------------------------------------
// See packet format in Packet.hpp to understand this
const uint64_t packetId = (
(((uint64_t)reinterpret_cast<const uint8_t *>(data)[0]) << 56) |
(((uint64_t)reinterpret_cast<const uint8_t *>(data)[1]) << 48) |
(((uint64_t)reinterpret_cast<const uint8_t *>(data)[2]) << 40) |
(((uint64_t)reinterpret_cast<const uint8_t *>(data)[3]) << 32) |
(((uint64_t)reinterpret_cast<const uint8_t *>(data)[4]) << 24) |
(((uint64_t)reinterpret_cast<const uint8_t *>(data)[5]) << 16) |
(((uint64_t)reinterpret_cast<const uint8_t *>(data)[6]) << 8) |
((uint64_t)reinterpret_cast<const uint8_t *>(data)[7])
);
const Address destination(reinterpret_cast<const uint8_t *>(data) + 8,ZT_ADDRESS_LENGTH);
const Address source(reinterpret_cast<const uint8_t *>(data) + 13,ZT_ADDRESS_LENGTH);
// Catch this and toss it -- it would never work, but it could happen if we somehow
// mistakenly guessed an address we're bound to as a destination for another peer.
if (source == RR->identity.address())
return;
//TRACE("<< %.16llx %s -> %s (size: %u)",(unsigned long long)packet->packetId(),source.toString().c_str(),destination.toString().c_str(),packet->size());
if (destination != RR->identity.address()) {
Packet packet(data,len);
// Packet is not for us, so try to relay it
if (packet.hops() < ZT_RELAY_MAX_HOPS) {
packet.incrementHops();
SharedPtr<Peer> relayTo = RR->topology->getPeer(destination);
if ((relayTo)&&((relayTo->send(packet.data(),packet.size(),now)))) {
Mutex::Lock _l(_lastUniteAttempt_m);
uint64_t &luts = _lastUniteAttempt[_LastUniteKey(source,destination)];
if ((now - luts) >= ZT_MIN_UNITE_INTERVAL) {
luts = now;
unite(source,destination);
}
} else {
#ifdef ZT_ENABLE_CLUSTER
if (RR->cluster) {
bool shouldUnite;
{
Mutex::Lock _l(_lastUniteAttempt_m);
uint64_t &luts = _lastUniteAttempt[_LastUniteKey(source,destination)];
shouldUnite = ((now - luts) >= ZT_MIN_UNITE_INTERVAL);
if (shouldUnite)
luts = now;
}
RR->cluster->sendViaCluster(source,destination,packet.data(),packet.size(),shouldUnite);
return;
}
#endif
relayTo = RR->topology->getBestRoot(&source,1,true);
if (relayTo)
relayTo->send(packet.data(),packet.size(),now);
}
} else {
TRACE("dropped relay %s(%s) -> %s, max hops exceeded",packet.source().toString().c_str(),fromAddr.toString().c_str(),destination.toString().c_str());
}
} else if ((reinterpret_cast<const uint8_t *>(data)[ZT_PACKET_IDX_FLAGS] & ZT_PROTO_FLAG_FRAGMENTED) != 0) {
// Packet is the head of a fragmented packet series
Mutex::Lock _l(_rxQueue_m);
RXQueueEntry *const rq = _findRXQueueEntry(now,packetId);
if ((!rq->timestamp)||(rq->packetId != packetId)) {
// If we have no other fragments yet, create an entry and save the head
//TRACE("fragment (0/?) of %.16llx from %s",pid,fromAddr.toString().c_str());
rq->timestamp = now;
rq->packetId = packetId;
rq->frag0.init(data,len,localAddr,fromAddr,now);
rq->totalFragments = 0;
rq->haveFragments = 1;
rq->complete = false;
} else if (!(rq->haveFragments & 1)) {
// If we have other fragments but no head, see if we are complete with the head
if ((rq->totalFragments > 1)&&(Utils::countBits(rq->haveFragments |= 1) == rq->totalFragments)) {
// We have all fragments -- assemble and process full Packet
//TRACE("packet %.16llx is complete, assembling and processing...",pid);
rq->frag0.init(data,len,localAddr,fromAddr,now);
for(unsigned int f=1;f<rq->totalFragments;++f)
rq->frag0.append(rq->frags[f - 1].payload(),rq->frags[f - 1].payloadLength());
if (rq->frag0.tryDecode(RR,false)) {
rq->timestamp = 0; // packet decoded, free entry
} else {
rq->complete = true; // set complete flag but leave entry since it probably needs WHOIS or something
}
} else {
// Still waiting on more fragments, but keep the head
rq->frag0.init(data,len,localAddr,fromAddr,now);
}
} // else this is a duplicate head, ignore
} else {
// Packet is unfragmented, so just process it
IncomingPacket packet(data,len,localAddr,fromAddr,now);
if (!packet.tryDecode(RR,false)) {
Mutex::Lock _l(_rxQueue_m);
RXQueueEntry *rq = &(_rxQueue[ZT_RX_QUEUE_SIZE - 1]);
unsigned long i = ZT_RX_QUEUE_SIZE - 1;
while ((i)&&(rq->timestamp)) {
RXQueueEntry *tmp = &(_rxQueue[--i]);
if (tmp->timestamp < rq->timestamp)
rq = tmp;
}
rq->timestamp = now;
rq->packetId = packetId;
rq->frag0 = packet;
rq->totalFragments = 1;
rq->haveFragments = 1;
rq->complete = true;
}
}
// --------------------------------------------------------------------
}
}
} catch (std::exception &ex) {
TRACE("dropped packet from %s: unexpected exception: %s",fromAddr.toString().c_str(),ex.what());
} catch ( ... ) {
TRACE("dropped packet from %s: unexpected exception: (unknown)",fromAddr.toString().c_str());
}
}
void Switch::onLocalEthernet(const SharedPtr<Network> &network,const MAC &from,const MAC &to,unsigned int etherType,unsigned int vlanId,const void *data,unsigned int len)
{
if (!network->hasConfig())
return;
// Sanity check -- bridge loop? OS problem?
if (to == network->mac())
return;
// Check to make sure this protocol is allowed on this network
if (!network->config().permitsEtherType(etherType)) {
TRACE("%.16llx: ignored tap: %s -> %s: ethertype %s not allowed on network %.16llx",network->id(),from.toString().c_str(),to.toString().c_str(),etherTypeName(etherType),(unsigned long long)network->id());
return;
}
// Check if this packet is from someone other than the tap -- i.e. bridged in
bool fromBridged = false;
if (from != network->mac()) {
if (!network->config().permitsBridging(RR->identity.address())) {
TRACE("%.16llx: %s -> %s %s not forwarded, bridging disabled or this peer not a bridge",network->id(),from.toString().c_str(),to.toString().c_str(),etherTypeName(etherType));
return;
}
fromBridged = true;
}
if (to.isMulticast()) {
// Destination is a multicast address (including broadcast)
MulticastGroup mg(to,0);
if (to.isBroadcast()) {
if ( (etherType == ZT_ETHERTYPE_ARP) && (len >= 28) && ((((const uint8_t *)data)[2] == 0x08)&&(((const uint8_t *)data)[3] == 0x00)&&(((const uint8_t *)data)[4] == 6)&&(((const uint8_t *)data)[5] == 4)&&(((const uint8_t *)data)[7] == 0x01)) ) {
/* IPv4 ARP is one of the few special cases that we impose upon what is
* otherwise a straightforward Ethernet switch emulation. Vanilla ARP
* is dumb old broadcast and simply doesn't scale. ZeroTier multicast
* groups have an additional field called ADI (additional distinguishing
* information) which was added specifically for ARP though it could
* be used for other things too. We then take ARP broadcasts and turn
* them into multicasts by stuffing the IP address being queried into
* the 32-bit ADI field. In practice this uses our multicast pub/sub
* system to implement a kind of extended/distributed ARP table. */
mg = MulticastGroup::deriveMulticastGroupForAddressResolution(InetAddress(((const unsigned char *)data) + 24,4,0));
} else if (!network->config().enableBroadcast()) {
// Don't transmit broadcasts if this network doesn't want them
TRACE("%.16llx: dropped broadcast since ff:ff:ff:ff:ff:ff is not enabled",network->id());
return;
}
} else if ((etherType == ZT_ETHERTYPE_IPV6)&&(len >= (40 + 8 + 16))) {
/* IPv6 NDP emulation on ZeroTier-RFC4193 addressed networks! This allows
* for multicast-free operation in IPv6 networks, which both improves
* performance and is friendlier to mobile and (especially) IoT devices.
* In the future there may be a no-multicast build option for embedded
* and IoT use and this will be the preferred addressing mode. Note that
* it plays nice with our L2 emulation philosophy and even with bridging.
* While "real" devices behind the bridge can't have ZT-RFC4193 addresses
* themselves, they can look these addresses up with NDP and it will
* work just fine. */
if ((reinterpret_cast<const uint8_t *>(data)[6] == 0x3a)&&(reinterpret_cast<const uint8_t *>(data)[40] == 0x87)) { // ICMPv6 neighbor solicitation
for(unsigned int sipk=0;sipk<network->config().staticIpCount;++sipk) {
const InetAddress *sip = &(network->config().staticIps[sipk]);
if ((sip->ss_family == AF_INET6)&&(Utils::ntoh((uint16_t)reinterpret_cast<const struct sockaddr_in6 *>(&(*sip))->sin6_port) == 88)) {
const uint8_t *my6 = reinterpret_cast<const uint8_t *>(reinterpret_cast<const struct sockaddr_in6 *>(&(*sip))->sin6_addr.s6_addr);
if ((my6[0] == 0xfd)&&(my6[9] == 0x99)&&(my6[10] == 0x93)) { // ZT-RFC4193 == fd__:____:____:____:__99:93__:____:____ / 88
const uint8_t *pkt6 = reinterpret_cast<const uint8_t *>(data) + 40 + 8;
unsigned int ptr = 0;
while (ptr != 11) {
if (pkt6[ptr] != my6[ptr])
break;
++ptr;
}
if (ptr == 11) { // /88 matches an assigned address on this network
const Address atPeer(pkt6 + ptr,5);
if (atPeer != RR->identity.address()) {
const MAC atPeerMac(atPeer,network->id());
TRACE("ZT-RFC4193 NDP emulation: %.16llx: forging response for %s/%s",network->id(),atPeer.toString().c_str(),atPeerMac.toString().c_str());
uint8_t adv[72];
adv[0] = 0x60; adv[1] = 0x00; adv[2] = 0x00; adv[3] = 0x00;
adv[4] = 0x00; adv[5] = 0x20;
adv[6] = 0x3a; adv[7] = 0xff;
for(int i=0;i<16;++i) adv[8 + i] = pkt6[i];
for(int i=0;i<16;++i) adv[24 + i] = my6[i];
adv[40] = 0x88; adv[41] = 0x00;
adv[42] = 0x00; adv[43] = 0x00; // future home of checksum
adv[44] = 0x60; adv[45] = 0x00; adv[46] = 0x00; adv[47] = 0x00;
for(int i=0;i<16;++i) adv[48 + i] = pkt6[i];
adv[64] = 0x02; adv[65] = 0x01;
adv[66] = atPeerMac[0]; adv[67] = atPeerMac[1]; adv[68] = atPeerMac[2]; adv[69] = atPeerMac[3]; adv[70] = atPeerMac[4]; adv[71] = atPeerMac[5];
uint16_t pseudo_[36];
uint8_t *const pseudo = reinterpret_cast<uint8_t *>(pseudo_);
for(int i=0;i<32;++i) pseudo[i] = adv[8 + i];
pseudo[32] = 0x00; pseudo[33] = 0x00; pseudo[34] = 0x00; pseudo[35] = 0x20;
pseudo[36] = 0x00; pseudo[37] = 0x00; pseudo[38] = 0x00; pseudo[39] = 0x3a;
for(int i=0;i<32;++i) pseudo[40 + i] = adv[40 + i];
uint32_t checksum = 0;
for(int i=0;i<36;++i) checksum += Utils::hton(pseudo_[i]);
while ((checksum >> 16)) checksum = (checksum & 0xffff) + (checksum >> 16);
checksum = ~checksum;
adv[42] = (checksum >> 8) & 0xff;
adv[43] = checksum & 0xff;
RR->node->putFrame(network->id(),network->userPtr(),atPeerMac,from,ZT_ETHERTYPE_IPV6,0,adv,72);
return; // stop processing: we have handled this frame with a spoofed local reply so no need to send it anywhere
}
}
}
}
}
}
}
/* Learn multicast groups for bridged-in hosts.
* Note that some OSes, most notably Linux, do this for you by learning
* multicast addresses on bridge interfaces and subscribing each slave.
* But in that case this does no harm, as the sets are just merged. */
if (fromBridged)
network->learnBridgedMulticastGroup(mg,RR->node->now());
//TRACE("%.16llx: MULTICAST %s -> %s %s %u",network->id(),from.toString().c_str(),mg.toString().c_str(),etherTypeName(etherType),len);
RR->mc->send(
((!network->config().isPublic())&&(network->config().com)) ? &(network->config().com) : (const CertificateOfMembership *)0,
network->config().multicastLimit,
RR->node->now(),
network->id(),
network->config().activeBridges(),
mg,
(fromBridged) ? from : MAC(),
etherType,
data,
len);
return;
}
if (to[0] == MAC::firstOctetForNetwork(network->id())) {
// Destination is another ZeroTier peer on the same network
Address toZT(to.toAddress(network->id())); // since in-network MACs are derived from addresses and network IDs, we can reverse this
SharedPtr<Peer> toPeer(RR->topology->getPeer(toZT));
const bool includeCom = ( (network->config().isPrivate()) && (network->config().com) && ((!toPeer)||(toPeer->needsOurNetworkMembershipCertificate(network->id(),RR->node->now(),true))) );
if ((fromBridged)||(includeCom)) {
Packet outp(toZT,RR->identity.address(),Packet::VERB_EXT_FRAME);
outp.append(network->id());
if (includeCom) {
outp.append((unsigned char)0x01); // 0x01 -- COM included
network->config().com.serialize(outp);
} else {
outp.append((unsigned char)0x00);
}
to.appendTo(outp);
from.appendTo(outp);
outp.append((uint16_t)etherType);
outp.append(data,len);
outp.compress();
send(outp,true,network->id());
} else {
Packet outp(toZT,RR->identity.address(),Packet::VERB_FRAME);
outp.append(network->id());
outp.append((uint16_t)etherType);
outp.append(data,len);
outp.compress();
send(outp,true,network->id());
}
//TRACE("%.16llx: UNICAST: %s -> %s etherType==%s(%.4x) vlanId==%u len==%u fromBridged==%d includeCom==%d",network->id(),from.toString().c_str(),to.toString().c_str(),etherTypeName(etherType),etherType,vlanId,len,(int)fromBridged,(int)includeCom);
return;
}
{
// Destination is bridged behind a remote peer
Address bridges[ZT_MAX_BRIDGE_SPAM];
unsigned int numBridges = 0;
/* Create an array of up to ZT_MAX_BRIDGE_SPAM recipients for this bridged frame. */
bridges[0] = network->findBridgeTo(to);
std::vector<Address> activeBridges(network->config().activeBridges());
if ((bridges[0])&&(bridges[0] != RR->identity.address())&&(network->config().permitsBridging(bridges[0]))) {
/* We have a known bridge route for this MAC, send it there. */
++numBridges;
} else if (!activeBridges.empty()) {
/* If there is no known route, spam to up to ZT_MAX_BRIDGE_SPAM active
* bridges. If someone responds, we'll learn the route. */
std::vector<Address>::const_iterator ab(activeBridges.begin());
if (activeBridges.size() <= ZT_MAX_BRIDGE_SPAM) {
// If there are <= ZT_MAX_BRIDGE_SPAM active bridges, spam them all
while (ab != activeBridges.end()) {
bridges[numBridges++] = *ab;
++ab;
}
} else {
// Otherwise pick a random set of them
while (numBridges < ZT_MAX_BRIDGE_SPAM) {
if (ab == activeBridges.end())
ab = activeBridges.begin();
if (((unsigned long)RR->node->prng() % (unsigned long)activeBridges.size()) == 0) {
bridges[numBridges++] = *ab;
++ab;
} else ++ab;
}
}
}
for(unsigned int b=0;b<numBridges;++b) {
SharedPtr<Peer> bridgePeer(RR->topology->getPeer(bridges[b]));
Packet outp(bridges[b],RR->identity.address(),Packet::VERB_EXT_FRAME);
outp.append(network->id());
if ( (network->config().isPrivate()) && (network->config().com) && ((!bridgePeer)||(bridgePeer->needsOurNetworkMembershipCertificate(network->id(),RR->node->now(),true))) ) {
outp.append((unsigned char)0x01); // 0x01 -- COM included
network->config().com.serialize(outp);
} else {
outp.append((unsigned char)0);
}
to.appendTo(outp);
from.appendTo(outp);
outp.append((uint16_t)etherType);
outp.append(data,len);
outp.compress();
send(outp,true,network->id());
}
}
}
void Switch::send(const Packet &packet,bool encrypt,uint64_t nwid)
{
if (packet.destination() == RR->identity.address()) {
TRACE("BUG: caught attempt to send() to self, ignored");
return;
}
//TRACE(">> %s to %s (%u bytes, encrypt==%d, nwid==%.16llx)",Packet::verbString(packet.verb()),packet.destination().toString().c_str(),packet.size(),(int)encrypt,nwid);
if (!_trySend(packet,encrypt,nwid)) {
Mutex::Lock _l(_txQueue_m);
_txQueue.push_back(TXQueueEntry(packet.destination(),RR->node->now(),packet,encrypt,nwid));
}
}
bool Switch::unite(const Address &p1,const Address &p2)
{
if ((p1 == RR->identity.address())||(p2 == RR->identity.address()))
return false;
SharedPtr<Peer> p1p = RR->topology->getPeer(p1);
if (!p1p)
return false;
SharedPtr<Peer> p2p = RR->topology->getPeer(p2);
if (!p2p)
return false;
const uint64_t now = RR->node->now();
std::pair<InetAddress,InetAddress> cg(Peer::findCommonGround(*p1p,*p2p,now));
if ((!(cg.first))||(cg.first.ipScope() != cg.second.ipScope()))
return false;
TRACE("unite: %s(%s) <> %s(%s)",p1.toString().c_str(),cg.second.toString().c_str(),p2.toString().c_str(),cg.first.toString().c_str());
/* Tell P1 where to find P2 and vice versa, sending the packets to P1 and
* P2 in randomized order in terms of which gets sent first. This is done
* since in a few cases NAT-t can be sensitive to slight timing differences
* in terms of when the two peers initiate. Normally this is accounted for
* by the nearly-simultaneous RENDEZVOUS kickoff from the relay, but
* given that relay are hosted on cloud providers this can in some
* cases have a few ms of latency between packet departures. By randomizing
* the order we make each attempted NAT-t favor one or the other going
* first, meaning if it doesn't succeed the first time it might the second
* and so forth. */
unsigned int alt = (unsigned int)RR->node->prng() & 1;
unsigned int completed = alt + 2;
while (alt != completed) {
if ((alt & 1) == 0) {
// Tell p1 where to find p2.
Packet outp(p1,RR->identity.address(),Packet::VERB_RENDEZVOUS);
outp.append((unsigned char)0);
p2.appendTo(outp);
outp.append((uint16_t)cg.first.port());
if (cg.first.isV6()) {
outp.append((unsigned char)16);
outp.append(cg.first.rawIpData(),16);
} else {
outp.append((unsigned char)4);
outp.append(cg.first.rawIpData(),4);
}
outp.armor(p1p->key(),true);
p1p->send(outp.data(),outp.size(),now);
} else {
// Tell p2 where to find p1.
Packet outp(p2,RR->identity.address(),Packet::VERB_RENDEZVOUS);
outp.append((unsigned char)0);
p1.appendTo(outp);
outp.append((uint16_t)cg.second.port());
if (cg.second.isV6()) {
outp.append((unsigned char)16);
outp.append(cg.second.rawIpData(),16);
} else {
outp.append((unsigned char)4);
outp.append(cg.second.rawIpData(),4);
}
outp.armor(p2p->key(),true);
p2p->send(outp.data(),outp.size(),now);
}
++alt; // counts up and also flips LSB
}
return true;
}
void Switch::rendezvous(const SharedPtr<Peer> &peer,const InetAddress &localAddr,const InetAddress &atAddr)
{
TRACE("sending NAT-t message to %s(%s)",peer->address().toString().c_str(),atAddr.toString().c_str());
const uint64_t now = RR->node->now();
peer->sendHELLO(localAddr,atAddr,now,2); // first attempt: send low-TTL packet to 'open' local NAT
{
Mutex::Lock _l(_contactQueue_m);
_contactQueue.push_back(ContactQueueEntry(peer,now + ZT_NAT_T_TACTICAL_ESCALATION_DELAY,localAddr,atAddr));
}
}
void Switch::requestWhois(const Address &addr)
{
bool inserted = false;
{
Mutex::Lock _l(_outstandingWhoisRequests_m);
WhoisRequest &r = _outstandingWhoisRequests[addr];
if (r.lastSent) {
r.retries = 0; // reset retry count if entry already existed, but keep waiting and retry again after normal timeout
} else {
r.lastSent = RR->node->now();
inserted = true;
}
}
if (inserted)
_sendWhoisRequest(addr,(const Address *)0,0);
}
void Switch::doAnythingWaitingForPeer(const SharedPtr<Peer> &peer)
{
{ // cancel pending WHOIS since we now know this peer
Mutex::Lock _l(_outstandingWhoisRequests_m);
_outstandingWhoisRequests.erase(peer->address());
}
{ // finish processing any packets waiting on peer's public key / identity
Mutex::Lock _l(_rxQueue_m);
unsigned long i = ZT_RX_QUEUE_SIZE;
while (i) {
RXQueueEntry *rq = &(_rxQueue[--i]);
if ((rq->timestamp)&&(rq->complete)) {
if (rq->frag0.tryDecode(RR,false))
rq->timestamp = 0;
}
}
}
{ // finish sending any packets waiting on peer's public key / identity
Mutex::Lock _l(_txQueue_m);
for(std::list< TXQueueEntry >::iterator txi(_txQueue.begin());txi!=_txQueue.end();) {
if (txi->dest == peer->address()) {
if (_trySend(txi->packet,txi->encrypt,txi->nwid))
_txQueue.erase(txi++);
else ++txi;
} else ++txi;
}
}
}
unsigned long Switch::doTimerTasks(uint64_t now)
{
unsigned long nextDelay = 0xffffffff; // ceiling delay, caller will cap to minimum
{ // Iterate through NAT traversal strategies for entries in contact queue
Mutex::Lock _l(_contactQueue_m);
for(std::list<ContactQueueEntry>::iterator qi(_contactQueue.begin());qi!=_contactQueue.end();) {
if (now >= qi->fireAtTime) {
if (!qi->peer->pushDirectPaths(qi->localAddr,qi->inaddr,now,true,false))
qi->peer->sendHELLO(qi->localAddr,qi->inaddr,now);
_contactQueue.erase(qi++);
continue;
/* Old symmetric NAT buster code, obsoleted by port prediction alg in SelfAwareness but left around for now in case we revert
if (qi->strategyIteration == 0) {
// First strategy: send packet directly to destination
qi->peer->sendHELLO(qi->localAddr,qi->inaddr,now);
} else if (qi->strategyIteration <= 3) {
// Strategies 1-3: try escalating ports for symmetric NATs that remap sequentially
InetAddress tmpaddr(qi->inaddr);
int p = (int)qi->inaddr.port() + qi->strategyIteration;
if (p > 65535)
p -= 64511;
tmpaddr.setPort((unsigned int)p);
qi->peer->sendHELLO(qi->localAddr,tmpaddr,now);
} else {
// All strategies tried, expire entry
_contactQueue.erase(qi++);
continue;
}
++qi->strategyIteration;
qi->fireAtTime = now + ZT_NAT_T_TACTICAL_ESCALATION_DELAY;
nextDelay = std::min(nextDelay,(unsigned long)ZT_NAT_T_TACTICAL_ESCALATION_DELAY);
*/
} else {
nextDelay = std::min(nextDelay,(unsigned long)(qi->fireAtTime - now));
}
++qi; // if qi was erased, loop will have continued before here
}
}
{ // Retry outstanding WHOIS requests
Mutex::Lock _l(_outstandingWhoisRequests_m);
Hashtable< Address,WhoisRequest >::Iterator i(_outstandingWhoisRequests);
Address *a = (Address *)0;
WhoisRequest *r = (WhoisRequest *)0;
while (i.next(a,r)) {
const unsigned long since = (unsigned long)(now - r->lastSent);
if (since >= ZT_WHOIS_RETRY_DELAY) {
if (r->retries >= ZT_MAX_WHOIS_RETRIES) {
TRACE("WHOIS %s timed out",a->toString().c_str());
_outstandingWhoisRequests.erase(*a);
} else {
r->lastSent = now;
r->peersConsulted[r->retries] = _sendWhoisRequest(*a,r->peersConsulted,r->retries);
++r->retries;
TRACE("WHOIS %s (retry %u)",a->toString().c_str(),r->retries);
nextDelay = std::min(nextDelay,(unsigned long)ZT_WHOIS_RETRY_DELAY);
}
} else {
nextDelay = std::min(nextDelay,ZT_WHOIS_RETRY_DELAY - since);
}
}
}
{ // Time out TX queue packets that never got WHOIS lookups or other info.
Mutex::Lock _l(_txQueue_m);
for(std::list< TXQueueEntry >::iterator txi(_txQueue.begin());txi!=_txQueue.end();) {
if (_trySend(txi->packet,txi->encrypt,txi->nwid))
_txQueue.erase(txi++);
else if ((now - txi->creationTime) > ZT_TRANSMIT_QUEUE_TIMEOUT) {
TRACE("TX %s -> %s timed out",txi->packet.source().toString().c_str(),txi->packet.destination().toString().c_str());
_txQueue.erase(txi++);
} else ++txi;
}
}
{ // Remove really old last unite attempt entries to keep table size controlled
Mutex::Lock _l(_lastUniteAttempt_m);
Hashtable< _LastUniteKey,uint64_t >::Iterator i(_lastUniteAttempt);
_LastUniteKey *k = (_LastUniteKey *)0;
uint64_t *v = (uint64_t *)0;
while (i.next(k,v)) {
if ((now - *v) >= (ZT_MIN_UNITE_INTERVAL * 8))
_lastUniteAttempt.erase(*k);
}
}
return nextDelay;
}
Address Switch::_sendWhoisRequest(const Address &addr,const Address *peersAlreadyConsulted,unsigned int numPeersAlreadyConsulted)
{
SharedPtr<Peer> root(RR->topology->getBestRoot(peersAlreadyConsulted,numPeersAlreadyConsulted,false));
if (root) {
Packet outp(root->address(),RR->identity.address(),Packet::VERB_WHOIS);
addr.appendTo(outp);
outp.armor(root->key(),true);
if (root->send(outp.data(),outp.size(),RR->node->now()))
return root->address();
}
return Address();
}
bool Switch::_trySend(const Packet &packet,bool encrypt,uint64_t nwid)
{
SharedPtr<Peer> peer(RR->topology->getPeer(packet.destination()));
if (peer) {
const uint64_t now = RR->node->now();
SharedPtr<Network> network;
if (nwid) {
network = RR->node->network(nwid);
if ((!network)||(!network->hasConfig()))
return false; // we probably just left this network, let its packets die
}
Path *viaPath = peer->getBestPath(now);
SharedPtr<Peer> relay;
if (!viaPath) {
if (network) {
unsigned int bestq = ~((unsigned int)0); // max unsigned int since quality is lower==better
unsigned int ptr = 0;
for(;;) {
const Address raddr(network->config().nextRelay(ptr));
if (raddr) {
SharedPtr<Peer> rp(RR->topology->getPeer(raddr));
if (rp) {
const unsigned int q = rp->relayQuality(now);
if (q < bestq) {
bestq = q;
rp.swap(relay);
}
}
} else break;
}
}
if (!relay)
relay = RR->topology->getBestRoot();
if ( (!relay) || (!(viaPath = relay->getBestPath(now))) )
return false;
}
// viaPath will not be null if we make it here
// Push possible direct paths to us if we are relaying
if (relay) {
peer->pushDirectPaths(viaPath->localAddress(),viaPath->address(),now,false,( (network)&&(network->isAllowed(peer)) ));
viaPath->sent(now);
}
Packet tmp(packet);
unsigned int chunkSize = std::min(tmp.size(),(unsigned int)ZT_UDP_DEFAULT_PAYLOAD_MTU);
tmp.setFragmented(chunkSize < tmp.size());
tmp.armor(peer->key(),encrypt);
if (viaPath->send(RR,tmp.data(),chunkSize,now)) {
if (chunkSize < tmp.size()) {
// Too big for one packet, fragment the rest
unsigned int fragStart = chunkSize;
unsigned int remaining = tmp.size() - chunkSize;
unsigned int fragsRemaining = (remaining / (ZT_UDP_DEFAULT_PAYLOAD_MTU - ZT_PROTO_MIN_FRAGMENT_LENGTH));
if ((fragsRemaining * (ZT_UDP_DEFAULT_PAYLOAD_MTU - ZT_PROTO_MIN_FRAGMENT_LENGTH)) < remaining)
++fragsRemaining;
unsigned int totalFragments = fragsRemaining + 1;
for(unsigned int fno=1;fno<totalFragments;++fno) {
chunkSize = std::min(remaining,(unsigned int)(ZT_UDP_DEFAULT_PAYLOAD_MTU - ZT_PROTO_MIN_FRAGMENT_LENGTH));
Packet::Fragment frag(tmp,fragStart,chunkSize,fno,totalFragments);
viaPath->send(RR,frag.data(),frag.size(),now);
fragStart += chunkSize;
remaining -= chunkSize;
}
}
return true;
}
} else {
requestWhois(packet.destination());
}
return false;
}
} // namespace ZeroTier
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