ZeroTierOne/node/Switch.cpp

/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at https://mozilla.org/MPL/2.0/.
 *
 * (c) ZeroTier, Inc.
 * https://www.zerotier.com/
 */

#include "Switch.hpp"

#include "../include/ZeroTierOne.h"
#include "Constants.hpp"
#include "InetAddress.hpp"
#include "Metrics.hpp"
#include "Node.hpp"
#include "Packet.hpp"
#include "Peer.hpp"
#include "RuntimeEnvironment.hpp"
#include "SelfAwareness.hpp"
#include "Topology.hpp"
#include "Trace.hpp"

#include <algorithm>
#include <stdio.h>
#include <stdlib.h>

namespace ZeroTier {

Switch::Switch(const RuntimeEnvironment* renv) : RR(renv), _lastBeaconResponse(0), _lastCheckedQueues(0), _lastUniteAttempt(8)
{
}

// Returns true if packet appears valid; pos and proto will be set
static bool _ipv6GetPayload(const uint8_t* frameData, unsigned int frameLen, unsigned int& pos, unsigned int& proto)
{
	if (frameLen < 40) {
		return false;
	}
	pos = 40;
	proto = frameData[6];
	while (pos <= frameLen) {
		switch (proto) {
			case 0:		// hop-by-hop options
			case 43:	// routing
			case 60:	// destination options
			case 135:	// mobility options
				if ((pos + 8) > frameLen) {
					return false;	// invalid!
				}
				proto = frameData[pos];
				pos += ((unsigned int)frameData[pos + 1] * 8) + 8;
				break;

			// case 44: // fragment -- we currently can't parse these and they are deprecated in IPv6 anyway
			// case 50:
			// case 51: // IPSec ESP and AH -- we have to stop here since this is encrypted stuff
			default:
				return true;
		}
	}
	return false;	// overflow == invalid
}

void Switch::onRemotePacket(void* tPtr, const int64_t localSocket, const InetAddress& fromAddr, const void* data, unsigned int len)
{
	int32_t flowId = ZT_QOS_NO_FLOW;
	try {
		const int64_t now = RR->node->now();

		const SharedPtr<Path> path(RR->topology->getPath(localSocket, fromAddr));
		path->received(now);

		if (len > ZT_PROTO_MIN_FRAGMENT_LENGTH) {
			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()) {
					// RELAY: fragment is for a different node, so maybe send it there if we should relay.
					if ((! RR->topology->amUpstream()) && (! path->trustEstablished(now))) {
						return;
					}

					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(tPtr, destination);
						if ((! relayTo) || (! relayTo->sendDirect(tPtr, fragment.data(), fragment.size(), now, false))) {
							// Don't know peer or no direct path -- so relay via someone upstream
							relayTo = RR->topology->getUpstreamPeer(0);
							if (relayTo) {
								relayTo->sendDirect(tPtr, fragment.data(), fragment.size(), now, true);
							}
						}
					}
				}
				else {
					// RECEIVE: fragment appears to be ours (this is validated in cryptographic auth after assembly)

					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?

						RXQueueEntry* const rq = _findRXQueueEntry(fragmentPacketId);
						Mutex::Lock rql(rq->lock);
						if (rq->packetId != fragmentPacketId) {
							// No packet found, so we received a fragment without its head.

							rq->flowId = flowId;
							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

							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

								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, tPtr, flowId)) {
									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 -------------------------------------------------

				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);

				if (source == RR->identity.address()) {
					return;
				}

				if (destination != RR->identity.address()) {
					// RELAY: packet head is for a different node, so maybe send it there if we should relay.

					if ((! RR->topology->amUpstream()) && (! path->trustEstablished(now)) && (source != RR->identity.address())) {
						return;
					}

					Packet packet(data, len);

					if (packet.hops() < ZT_RELAY_MAX_HOPS) {
						packet.incrementHops();
						SharedPtr<Peer> relayTo = RR->topology->getPeer(tPtr, destination);
						if ((relayTo) && (relayTo->sendDirect(tPtr, packet.data(), packet.size(), now, false))) {
							if ((source != RR->identity.address()) && (_shouldUnite(now, source, destination))) {
								const SharedPtr<Peer> sourcePeer(RR->topology->getPeer(tPtr, source));
								if (sourcePeer) {
									relayTo->introduce(tPtr, now, sourcePeer);
								}
							}
						}
						else {
							relayTo = RR->topology->getUpstreamPeer(0);
							if ((relayTo) && (relayTo->address() != source)) {
								if (relayTo->sendDirect(tPtr, packet.data(), packet.size(), now, true)) {
									const SharedPtr<Peer> sourcePeer(RR->topology->getPeer(tPtr, source));
									if (sourcePeer) {
										relayTo->introduce(tPtr, now, sourcePeer);
									}
								}
							}
						}
					}
				}
				else if ((reinterpret_cast<const uint8_t*>(data)[ZT_PACKET_IDX_FLAGS] & ZT_PROTO_FLAG_FRAGMENTED) != 0) {
					// RECEIVE: packet head appears to be ours (this is validated in cryptographic auth after assembly)

					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]));

					RXQueueEntry* const rq = _findRXQueueEntry(packetId);
					Mutex::Lock rql(rq->lock);
					if (rq->packetId != packetId) {
						// If we have no other fragments yet, create an entry and save the head

						rq->flowId = flowId;
						rq->timestamp = now;
						rq->packetId = packetId;
						rq->frag0.init(data, len, path, 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

							rq->frag0.init(data, len, path, 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, tPtr, flowId)) {
								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, path, now);
						}
					}	// else this is a duplicate head, ignore
				}
				else {
					// RECEIVE: unfragmented packet appears to be ours (this is validated in cryptographic auth after assembly)

					IncomingPacket packet(data, len, path, now);
					if (! packet.tryDecode(RR, tPtr, flowId)) {
						RXQueueEntry* const rq = _nextRXQueueEntry();
						Mutex::Lock rql(rq->lock);
						rq->flowId = flowId;
						rq->timestamp = now;
						rq->packetId = packet.packetId();
						rq->frag0 = packet;
						rq->totalFragments = 1;
						rq->haveFragments = 1;
						rq->complete = true;
					}
				}

				// --------------------------------------------------------------------
			}
		}
	}
	catch (...) {
	}	// sanity check, should be caught elsewhere
}

void Switch::onLocalEthernet(void* tPtr, 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;
	}

	// Check if this packet is from someone other than the tap -- i.e. bridged in
	bool fromBridged;
	if ((fromBridged = (from != network->mac()))) {
		if (! network->config().permitsBridging(RR->identity.address())) {
			RR->t->outgoingNetworkFrameDropped(tPtr, network, from, to, etherType, vlanId, len, "not a bridge");
			return;
		}
	}

	uint8_t qosBucket = ZT_AQM_DEFAULT_BUCKET;

	/**
	 * A pseudo-unique identifier used by balancing and bonding policies to
	 * categorize individual flows/conversations for assignment to a specific
	 * physical path. This identifier consists of the source port and
	 * destination port of the encapsulated frame.
	 *
	 * A flowId of -1 will indicate that there is no preference for how this
	 * packet shall be sent. An example of this would be an ICMP packet.
	 */

	int32_t flowId = ZT_QOS_NO_FLOW;

	if (etherType == ZT_ETHERTYPE_IPV4 && (len >= 20)) {
		uint16_t srcPort = 0;
		uint16_t dstPort = 0;
		uint8_t proto = (reinterpret_cast<const uint8_t*>(data)[9]);
		const unsigned int headerLen = 4 * (reinterpret_cast<const uint8_t*>(data)[0] & 0xf);
		switch (proto) {
			case 0x01:	 // ICMP
				// flowId = 0x01;
				break;
			// All these start with 16-bit source and destination port in that order
			case 0x06:	 // TCP
			case 0x11:	 // UDP
			case 0x84:	 // SCTP
			case 0x88:	 // UDPLite
				if (len > (headerLen + 4)) {
					unsigned int pos = headerLen + 0;
					srcPort = (reinterpret_cast<const uint8_t*>(data)[pos++]) << 8;
					srcPort |= (reinterpret_cast<const uint8_t*>(data)[pos]);
					pos++;
					dstPort = (reinterpret_cast<const uint8_t*>(data)[pos++]) << 8;
					dstPort |= (reinterpret_cast<const uint8_t*>(data)[pos]);
					flowId = dstPort ^ srcPort ^ proto;
				}
				break;
		}
	}

	if (etherType == ZT_ETHERTYPE_IPV6 && (len >= 40)) {
		uint16_t srcPort = 0;
		uint16_t dstPort = 0;
		unsigned int pos;
		unsigned int proto;
		_ipv6GetPayload((const uint8_t*)data, len, pos, proto);
		switch (proto) {
			case 0x3A:	 // ICMPv6
				// flowId = 0x3A;
				break;
			// All these start with 16-bit source and destination port in that order
			case 0x06:	 // TCP
			case 0x11:	 // UDP
			case 0x84:	 // SCTP
			case 0x88:	 // UDPLite
				if (len > (pos + 4)) {
					srcPort = (reinterpret_cast<const uint8_t*>(data)[pos++]) << 8;
					srcPort |= (reinterpret_cast<const uint8_t*>(data)[pos]);
					pos++;
					dstPort = (reinterpret_cast<const uint8_t*>(data)[pos++]) << 8;
					dstPort |= (reinterpret_cast<const uint8_t*>(data)[pos]);
					flowId = dstPort ^ srcPort ^ proto;
				}
				break;
			default:
				break;
		}
	}

	if (to.isMulticast()) {
		MulticastGroup multicastGroup(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. */
				multicastGroup = 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
				RR->t->outgoingNetworkFrameDropped(tPtr, network, from, to, etherType, vlanId, len, "broadcast disabled");
				return;
			}
		}
		else if ((etherType == ZT_ETHERTYPE_IPV6) && (len >= (40 + 8 + 16))) {
			// IPv6 NDP emulation for certain very special patterns of private IPv6 addresses -- if enabled
			if ((network->config().ndpEmulation()) && (reinterpret_cast<const uint8_t*>(data)[6] == 0x3a) && (reinterpret_cast<const uint8_t*>(data)[40] == 0x87)) {   // ICMPv6 neighbor solicitation
				Address v6EmbeddedAddress;
				const uint8_t* const pkt6 = reinterpret_cast<const uint8_t*>(data) + 40 + 8;
				const uint8_t* my6 = (const uint8_t*)0;

				// ZT-RFC4193 address: fdNN:NNNN:NNNN:NNNN:NN99:93DD:DDDD:DDDD / 88 (one /128 per actual host)

				// ZT-6PLANE address:  fcXX:XXXX:XXDD:DDDD:DDDD:####:####:#### / 40 (one /80 per actual host)
				// (XX - lower 32 bits of network ID XORed with higher 32 bits)

				// For these to work, we must have a ZT-managed address assigned in one of the
				// above formats, and the query must match its prefix.
				for (unsigned int sipk = 0; sipk < network->config().staticIpCount; ++sipk) {
					const InetAddress* const sip = &(network->config().staticIps[sipk]);
					if (sip->ss_family == AF_INET6) {
						my6 = reinterpret_cast<const uint8_t*>(reinterpret_cast<const struct sockaddr_in6*>(&(*sip))->sin6_addr.s6_addr);
						const unsigned int sipNetmaskBits = Utils::ntoh((uint16_t)reinterpret_cast<const struct sockaddr_in6*>(&(*sip))->sin6_port);
						if ((sipNetmaskBits == 88) && (my6[0] == 0xfd) && (my6[9] == 0x99) && (my6[10] == 0x93)) {	 // ZT-RFC4193 /88 ???
							unsigned int ptr = 0;
							while (ptr != 11) {
								if (pkt6[ptr] != my6[ptr]) {
									break;
								}
								++ptr;
							}
							if (ptr == 11) {   // prefix match!
								v6EmbeddedAddress.setTo(pkt6 + ptr, 5);
								break;
							}
						}
						else if (sipNetmaskBits == 40) {   // ZT-6PLANE /40 ???
							const uint32_t nwid32 = (uint32_t)((network->id() ^ (network->id() >> 32)) & 0xffffffff);
							if ((my6[0] == 0xfc) && (my6[1] == (uint8_t)((nwid32 >> 24) & 0xff)) && (my6[2] == (uint8_t)((nwid32 >> 16) & 0xff)) && (my6[3] == (uint8_t)((nwid32 >> 8) & 0xff)) && (my6[4] == (uint8_t)(nwid32 & 0xff))) {
								unsigned int ptr = 0;
								while (ptr != 5) {
									if (pkt6[ptr] != my6[ptr]) {
										break;
									}
									++ptr;
								}
								if (ptr == 5) {	  // prefix match!
									v6EmbeddedAddress.setTo(pkt6 + ptr, 5);
									break;
								}
							}
						}
					}
				}

				if ((v6EmbeddedAddress) && (v6EmbeddedAddress != RR->identity.address())) {
					const MAC peerMac(v6EmbeddedAddress, network->id());

					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] = peerMac[0];
					adv[67] = peerMac[1];
					adv[68] = peerMac[2];
					adv[69] = peerMac[3];
					adv[70] = peerMac[4];
					adv[71] = peerMac[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;

					//
					// call on separate background thread
					// this prevents problems related to trying to do rx while inside of doing tx, such as acquiring same lock recursively
					//

					std::thread([=]() { RR->node->putFrame(tPtr, network->id(), network->userPtr(), peerMac, from, ZT_ETHERTYPE_IPV6, 0, adv, 72); }).detach();

					return;	  // NDP emulation done. We have forged a "fake" reply, so no need to send actual NDP query.
				}	// else no NDP emulation
			}	// else no NDP emulation
		}

		// Check this after NDP emulation, since that has to be allowed in exactly this case
		if (network->config().multicastLimit == 0) {
			RR->t->outgoingNetworkFrameDropped(tPtr, network, from, to, etherType, vlanId, len, "multicast disabled");
			return;
		}

		/* 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(tPtr, multicastGroup, RR->node->now());
		}

		// First pass sets noTee to false, but noTee is set to true in OutboundMulticast to prevent duplicates.
		if (! network->filterOutgoingPacket(tPtr, false, RR->identity.address(), Address(), from, to, (const uint8_t*)data, len, etherType, vlanId, qosBucket)) {
			RR->t->outgoingNetworkFrameDropped(tPtr, network, from, to, etherType, vlanId, len, "filter blocked");
			return;
		}

		RR->mc->send(tPtr, RR->node->now(), network, Address(), multicastGroup, (fromBridged) ? from : MAC(), etherType, data, len);
	}
	else if (to == network->mac()) {
		// Destination is this node, so just reinject it

		//
		// same pattern as putFrame call above
		//
		std::thread([=]() { RR->node->putFrame(tPtr, network->id(), network->userPtr(), from, to, etherType, vlanId, data, len); }).detach();
	}
	else 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(tPtr, toZT));

		if (! network->filterOutgoingPacket(tPtr, false, RR->identity.address(), toZT, from, to, (const uint8_t*)data, len, etherType, vlanId, qosBucket)) {
			RR->t->outgoingNetworkFrameDropped(tPtr, network, from, to, etherType, vlanId, len, "filter blocked");
			return;
		}

		network->pushCredentialsIfNeeded(tPtr, toZT, RR->node->now());

		if (! fromBridged) {
			Packet outp(toZT, RR->identity.address(), Packet::VERB_FRAME);
			outp.append(network->id());
			outp.append((uint16_t)etherType);
			outp.append(data, len);
			aqm_enqueue(tPtr, network, outp, true, qosBucket, network->id(), flowId);
		}
		else {
			Packet outp(toZT, RR->identity.address(), Packet::VERB_EXT_FRAME);
			outp.append(network->id());
			outp.append((unsigned char)0x00);
			to.appendTo(outp);
			from.appendTo(outp);
			outp.append((uint16_t)etherType);
			outp.append(data, len);
			aqm_enqueue(tPtr, network, outp, true, qosBucket, network->id(), flowId);
		}
	}
	else {
		// Destination is bridged behind a remote peer

		// We filter with a NULL destination ZeroTier address first. Filtrations
		// for each ZT destination are also done below. This is the same rationale
		// and design as for multicast.
		if (! network->filterOutgoingPacket(tPtr, false, RR->identity.address(), Address(), from, to, (const uint8_t*)data, len, etherType, vlanId, qosBucket)) {
			RR->t->outgoingNetworkFrameDropped(tPtr, network, from, to, etherType, vlanId, len, "filter blocked");
			return;
		}

		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) {
			if (network->filterOutgoingPacket(tPtr, true, RR->identity.address(), bridges[b], from, to, (const uint8_t*)data, len, etherType, vlanId, qosBucket)) {
				Packet outp(bridges[b], RR->identity.address(), Packet::VERB_EXT_FRAME);
				outp.append(network->id());
				outp.append((uint8_t)0x00);
				to.appendTo(outp);
				from.appendTo(outp);
				outp.append((uint16_t)etherType);
				outp.append(data, len);
				aqm_enqueue(tPtr, network, outp, true, qosBucket, network->id(), flowId);
			}
			else {
				RR->t->outgoingNetworkFrameDropped(tPtr, network, from, to, etherType, vlanId, len, "filter blocked (bridge replication)");
			}
		}
	}
}

void Switch::aqm_enqueue(void* tPtr, const SharedPtr<Network>& network, Packet& packet, const bool encrypt, const int qosBucket, const uint64_t nwid, const int32_t flowId)
{
	if (! network->qosEnabled()) {
		send(tPtr, packet, encrypt, nwid, flowId);
		return;
	}
	NetworkQoSControlBlock* nqcb = _netQueueControlBlock[network->id()];
	if (! nqcb) {
		nqcb = new NetworkQoSControlBlock();
		_netQueueControlBlock[network->id()] = nqcb;
		// Initialize ZT_QOS_NUM_BUCKETS queues and place them in the INACTIVE list
		// These queues will be shuffled between the new/old/inactive lists by the enqueue/dequeue algorithm
		for (int i = 0; i < ZT_AQM_NUM_BUCKETS; i++) {
			nqcb->inactiveQueues.push_back(new ManagedQueue(i));
		}
	}
	// Don't apply QoS scheduling to ZT protocol traffic
	if (packet.verb() != Packet::VERB_FRAME && packet.verb() != Packet::VERB_EXT_FRAME) {
		send(tPtr, packet, encrypt, nwid, flowId);
	}

	_aqm_m.lock();

	// Enqueue packet and move queue to appropriate list

	const Address dest(packet.destination());
	TXQueueEntry* txEntry = new TXQueueEntry(dest, nwid, RR->node->now(), packet, encrypt, flowId);

	ManagedQueue* selectedQueue = nullptr;
	for (size_t i = 0; i < ZT_AQM_NUM_BUCKETS; i++) {
		if (i < nqcb->oldQueues.size()) {	// search old queues first (I think this is best since old would imply most recent usage of the queue)
			if (nqcb->oldQueues[i]->id == qosBucket) {
				selectedQueue = nqcb->oldQueues[i];
			}
		}
		if (i < nqcb->newQueues.size()) {	// search new queues (this would imply not often-used queues)
			if (nqcb->newQueues[i]->id == qosBucket) {
				selectedQueue = nqcb->newQueues[i];
			}
		}
		if (i < nqcb->inactiveQueues.size()) {	 // search inactive queues
			if (nqcb->inactiveQueues[i]->id == qosBucket) {
				selectedQueue = nqcb->inactiveQueues[i];
				// move queue to end of NEW queue list
				selectedQueue->byteCredit = ZT_AQM_QUANTUM;
				// DEBUG_INFO("moving q=%p from INACTIVE to NEW list", selectedQueue);
				nqcb->newQueues.push_back(selectedQueue);
				nqcb->inactiveQueues.erase(nqcb->inactiveQueues.begin() + i);
			}
		}
	}
	if (! selectedQueue) {
		_aqm_m.unlock();
		return;
	}

	selectedQueue->q.push_back(txEntry);
	selectedQueue->byteLength += txEntry->packet.payloadLength();
	nqcb->_currEnqueuedPackets++;

	// DEBUG_INFO("nq=%2lu, oq=%2lu, iq=%2lu, nqcb.size()=%3d, bucket=%2d, q=%p", nqcb->newQueues.size(), nqcb->oldQueues.size(), nqcb->inactiveQueues.size(), nqcb->_currEnqueuedPackets, qosBucket, selectedQueue);

	// Drop a packet if necessary
	ManagedQueue* selectedQueueToDropFrom = nullptr;
	if (nqcb->_currEnqueuedPackets > ZT_AQM_MAX_ENQUEUED_PACKETS) {
		// DEBUG_INFO("too many enqueued packets (%d), finding packet to drop", nqcb->_currEnqueuedPackets);
		int maxQueueLength = 0;
		for (size_t i = 0; i < ZT_AQM_NUM_BUCKETS; i++) {
			if (i < nqcb->oldQueues.size()) {
				if (nqcb->oldQueues[i]->byteLength > maxQueueLength) {
					maxQueueLength = nqcb->oldQueues[i]->byteLength;
					selectedQueueToDropFrom = nqcb->oldQueues[i];
				}
			}
			if (i < nqcb->newQueues.size()) {
				if (nqcb->newQueues[i]->byteLength > maxQueueLength) {
					maxQueueLength = nqcb->newQueues[i]->byteLength;
					selectedQueueToDropFrom = nqcb->newQueues[i];
				}
			}
			if (i < nqcb->inactiveQueues.size()) {
				if (nqcb->inactiveQueues[i]->byteLength > maxQueueLength) {
					maxQueueLength = nqcb->inactiveQueues[i]->byteLength;
					selectedQueueToDropFrom = nqcb->inactiveQueues[i];
				}
			}
		}
		if (selectedQueueToDropFrom) {
			// DEBUG_INFO("dropping packet from head of largest queue (%d payload bytes)", maxQueueLength);
			int sizeOfDroppedPacket = selectedQueueToDropFrom->q.front()->packet.payloadLength();
			delete selectedQueueToDropFrom->q.front();
			selectedQueueToDropFrom->q.pop_front();
			selectedQueueToDropFrom->byteLength -= sizeOfDroppedPacket;
			nqcb->_currEnqueuedPackets--;
		}
	}
	_aqm_m.unlock();
	aqm_dequeue(tPtr);
}

uint64_t Switch::control_law(uint64_t t, int count)
{
	return (uint64_t)(t + ZT_AQM_INTERVAL / sqrt(count));
}

Switch::dqr Switch::dodequeue(ManagedQueue* q, uint64_t now)
{
	dqr r;
	r.ok_to_drop = false;
	r.p = q->q.front();

	if (r.p == NULL) {
		q->first_above_time = 0;
		return r;
	}
	uint64_t sojourn_time = now - r.p->creationTime;
	if (sojourn_time < ZT_AQM_TARGET || q->byteLength <= ZT_DEFAULT_MTU) {
		// went below - stay below for at least interval
		q->first_above_time = 0;
	}
	else {
		if (q->first_above_time == 0) {
			// just went above from below. if still above at
			// first_above_time, will say it's ok to drop.
			q->first_above_time = now + ZT_AQM_INTERVAL;
		}
		else if (now >= q->first_above_time) {
			r.ok_to_drop = true;
		}
	}
	return r;
}

Switch::TXQueueEntry* Switch::CoDelDequeue(ManagedQueue* q, bool isNew, uint64_t now)
{
	dqr r = dodequeue(q, now);

	if (q->dropping) {
		if (! r.ok_to_drop) {
			q->dropping = false;
		}
		while (now >= q->drop_next && q->dropping) {
			q->q.pop_front();	// drop
			r = dodequeue(q, now);
			if (! r.ok_to_drop) {
				// leave dropping state
				q->dropping = false;
			}
			else {
				++(q->count);
				// schedule the next drop.
				q->drop_next = control_law(q->drop_next, q->count);
			}
		}
	}
	else if (r.ok_to_drop) {
		q->q.pop_front();	// drop
		r = dodequeue(q, now);
		q->dropping = true;
		q->count = (q->count > 2 && now - q->drop_next < 8 * ZT_AQM_INTERVAL) ? q->count - 2 : 1;
		q->drop_next = control_law(now, q->count);
	}
	return r.p;
}

void Switch::aqm_dequeue(void* tPtr)
{
	// Cycle through network-specific QoS control blocks
	for (std::map<uint64_t, NetworkQoSControlBlock*>::iterator nqcb(_netQueueControlBlock.begin()); nqcb != _netQueueControlBlock.end();) {
		if (! (*nqcb).second->_currEnqueuedPackets) {
			return;
		}

		uint64_t now = RR->node->now();
		TXQueueEntry* entryToEmit = nullptr;
		std::vector<ManagedQueue*>* currQueues = &((*nqcb).second->newQueues);
		std::vector<ManagedQueue*>* oldQueues = &((*nqcb).second->oldQueues);
		std::vector<ManagedQueue*>* inactiveQueues = &((*nqcb).second->inactiveQueues);

		_aqm_m.lock();

		// Attempt dequeue from queues in NEW list
		bool examiningNewQueues = true;
		while (currQueues->size()) {
			ManagedQueue* queueAtFrontOfList = currQueues->front();
			if (queueAtFrontOfList->byteCredit < 0) {
				queueAtFrontOfList->byteCredit += ZT_AQM_QUANTUM;
				// Move to list of OLD queues
				// DEBUG_INFO("moving q=%p from NEW to OLD list", queueAtFrontOfList);
				oldQueues->push_back(queueAtFrontOfList);
				currQueues->erase(currQueues->begin());
			}
			else {
				entryToEmit = CoDelDequeue(queueAtFrontOfList, examiningNewQueues, now);
				if (! entryToEmit) {
					// Move to end of list of OLD queues
					// DEBUG_INFO("moving q=%p from NEW to OLD list", queueAtFrontOfList);
					oldQueues->push_back(queueAtFrontOfList);
					currQueues->erase(currQueues->begin());
				}
				else {
					int len = entryToEmit->packet.payloadLength();
					queueAtFrontOfList->byteLength -= len;
					queueAtFrontOfList->byteCredit -= len;
					// Send the packet!
					queueAtFrontOfList->q.pop_front();
					send(tPtr, entryToEmit->packet, entryToEmit->encrypt, entryToEmit->nwid, entryToEmit->flowId);
					(*nqcb).second->_currEnqueuedPackets--;
				}
				if (queueAtFrontOfList) {
					// DEBUG_INFO("dequeuing from q=%p, len=%lu in NEW list (byteCredit=%d)", queueAtFrontOfList, queueAtFrontOfList->q.size(), queueAtFrontOfList->byteCredit);
				}
				break;
			}
		}

		// Attempt dequeue from queues in OLD list
		examiningNewQueues = false;
		currQueues = &((*nqcb).second->oldQueues);
		while (currQueues->size()) {
			ManagedQueue* queueAtFrontOfList = currQueues->front();
			if (queueAtFrontOfList->byteCredit < 0) {
				queueAtFrontOfList->byteCredit += ZT_AQM_QUANTUM;
				oldQueues->push_back(queueAtFrontOfList);
				currQueues->erase(currQueues->begin());
			}
			else {
				entryToEmit = CoDelDequeue(queueAtFrontOfList, examiningNewQueues, now);
				if (! entryToEmit) {
					// DEBUG_INFO("moving q=%p from OLD to INACTIVE list", queueAtFrontOfList);
					//  Move to inactive list of queues
					inactiveQueues->push_back(queueAtFrontOfList);
					currQueues->erase(currQueues->begin());
				}
				else {
					int len = entryToEmit->packet.payloadLength();
					queueAtFrontOfList->byteLength -= len;
					queueAtFrontOfList->byteCredit -= len;
					queueAtFrontOfList->q.pop_front();
					send(tPtr, entryToEmit->packet, entryToEmit->encrypt, entryToEmit->nwid, entryToEmit->flowId);
					(*nqcb).second->_currEnqueuedPackets--;
				}
				if (queueAtFrontOfList) {
					// DEBUG_INFO("dequeuing from q=%p, len=%lu in OLD list (byteCredit=%d)", queueAtFrontOfList, queueAtFrontOfList->q.size(), queueAtFrontOfList->byteCredit);
				}
				break;
			}
		}
		nqcb++;
		_aqm_m.unlock();
	}
}

void Switch::removeNetworkQoSControlBlock(uint64_t nwid)
{
	NetworkQoSControlBlock* nq = _netQueueControlBlock[nwid];
	if (nq) {
		_netQueueControlBlock.erase(nwid);
		delete nq;
		nq = NULL;
	}
}

void Switch::send(void* tPtr, Packet& packet, const bool encrypt, const uint64_t nwid, const int32_t flowId)
{
	const Address dest(packet.destination());
	if (dest == RR->identity.address()) {
		return;
	}
	_recordOutgoingPacketMetrics(packet);
	if (! _trySend(tPtr, packet, encrypt, nwid, flowId)) {
		{
			Mutex::Lock _l(_txQueue_m);
			if (_txQueue.size() >= ZT_TX_QUEUE_SIZE) {
				_txQueue.pop_front();
			}
			_txQueue.push_back(TXQueueEntry(dest, nwid, RR->node->now(), packet, encrypt, flowId));
		}
		if (! RR->topology->getPeer(tPtr, dest)) {
			requestWhois(tPtr, RR->node->now(), dest);
		}
	}
}

void Switch::requestWhois(void* tPtr, const int64_t now, const Address& addr)
{
	if (addr == RR->identity.address()) {
		return;
	}

	{
		Mutex::Lock _l(_lastSentWhoisRequest_m);
		int64_t& last = _lastSentWhoisRequest[addr];
		if ((now - last) < ZT_WHOIS_RETRY_DELAY) {
			return;
		}
		else {
			last = now;
		}
	}

	const SharedPtr<Peer> upstream(RR->topology->getUpstreamPeer(0));
	if (upstream) {
		int32_t flowId = ZT_QOS_NO_FLOW;
		Packet outp(upstream->address(), RR->identity.address(), Packet::VERB_WHOIS);
		addr.appendTo(outp);
		send(tPtr, outp, true, 0, flowId);
	}
}

void Switch::doAnythingWaitingForPeer(void* tPtr, const SharedPtr<Peer>& peer)
{
	{
		Mutex::Lock _l(_lastSentWhoisRequest_m);
		_lastSentWhoisRequest.erase(peer->address());
	}

	const int64_t now = RR->node->now();
	for (unsigned int ptr = 0; ptr < ZT_RX_QUEUE_SIZE; ++ptr) {
		RXQueueEntry* const rq = &(_rxQueue[ptr]);
		Mutex::Lock rql(rq->lock);
		if ((rq->timestamp) && (rq->complete)) {
			if ((rq->frag0.tryDecode(RR, tPtr, rq->flowId)) || ((now - rq->timestamp) > ZT_RECEIVE_QUEUE_TIMEOUT)) {
				rq->timestamp = 0;
			}
		}
	}

	{
		Mutex::Lock _l(_txQueue_m);
		for (std::list<TXQueueEntry>::iterator txi(_txQueue.begin()); txi != _txQueue.end();) {
			if (txi->dest == peer->address()) {
				if (_trySend(tPtr, txi->packet, txi->encrypt, txi->nwid, txi->flowId)) {
					_txQueue.erase(txi++);
				}
				else {
					++txi;
				}
			}
			else {
				++txi;
			}
		}
	}
}

unsigned long Switch::doTimerTasks(void* tPtr, int64_t now)
{
	const uint64_t timeSinceLastCheck = now - _lastCheckedQueues;
	if (timeSinceLastCheck < ZT_WHOIS_RETRY_DELAY) {
		return (unsigned long)(ZT_WHOIS_RETRY_DELAY - timeSinceLastCheck);
	}
	_lastCheckedQueues = now;

	std::vector<Address> needWhois;
	{
		Mutex::Lock _l(_txQueue_m);

		for (std::list<TXQueueEntry>::iterator txi(_txQueue.begin()); txi != _txQueue.end();) {
			if (_trySend(tPtr, txi->packet, txi->encrypt, 0, txi->flowId)) {
				_txQueue.erase(txi++);
			}
			else if ((now - txi->creationTime) > ZT_TRANSMIT_QUEUE_TIMEOUT) {
				_txQueue.erase(txi++);
			}
			else {
				if (! RR->topology->getPeer(tPtr, txi->dest)) {
					needWhois.push_back(txi->dest);
				}
				++txi;
			}
		}
	}
	for (std::vector<Address>::const_iterator i(needWhois.begin()); i != needWhois.end(); ++i) {
		requestWhois(tPtr, now, *i);
	}

	for (unsigned int ptr = 0; ptr < ZT_RX_QUEUE_SIZE; ++ptr) {
		RXQueueEntry* const rq = &(_rxQueue[ptr]);
		Mutex::Lock rql(rq->lock);
		if ((rq->timestamp) && (rq->complete)) {
			if ((rq->frag0.tryDecode(RR, tPtr, rq->flowId)) || ((now - rq->timestamp) > ZT_RECEIVE_QUEUE_TIMEOUT)) {
				rq->timestamp = 0;
			}
			else {
				const Address src(rq->frag0.source());
				if (! RR->topology->getPeer(tPtr, src)) {
					requestWhois(tPtr, now, src);
				}
			}
		}
	}

	{
		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);
			}
		}
	}

	{
		Mutex::Lock _l(_lastSentWhoisRequest_m);
		Hashtable<Address, int64_t>::Iterator i(_lastSentWhoisRequest);
		Address* a = (Address*)0;
		int64_t* ts = (int64_t*)0;
		while (i.next(a, ts)) {
			if ((now - *ts) > (ZT_WHOIS_RETRY_DELAY * 2)) {
				_lastSentWhoisRequest.erase(*a);
			}
		}
	}

	return ZT_WHOIS_RETRY_DELAY;
}

bool Switch::_shouldUnite(const int64_t now, const Address& source, const Address& destination)
{
	Mutex::Lock _l(_lastUniteAttempt_m);
	uint64_t& ts = _lastUniteAttempt[_LastUniteKey(source, destination)];
	if ((now - ts) >= ZT_MIN_UNITE_INTERVAL) {
		ts = now;
		return true;
	}
	return false;
}

bool Switch::_trySend(void* tPtr, Packet& packet, bool encrypt, const uint64_t nwid, const int32_t flowId)
{
	SharedPtr<Path> viaPath;
	const int64_t now = RR->node->now();
	const Address destination(packet.destination());

	const SharedPtr<Peer> peer(RR->topology->getPeer(tPtr, destination));
	if (peer) {
		if ((peer->bondingPolicy() == ZT_BOND_POLICY_BROADCAST) && (packet.verb() == Packet::VERB_FRAME || packet.verb() == Packet::VERB_EXT_FRAME)) {
			const SharedPtr<Peer> relay(RR->topology->getUpstreamPeer(nwid));
			Mutex::Lock _l(peer->_paths_m);
			for (int i = 0; i < ZT_MAX_PEER_NETWORK_PATHS; ++i) {
				if (peer->_paths[i].p && peer->_paths[i].p->alive(now)) {
					uint16_t userSpecifiedMtu = peer->_paths[i].p->mtu();
					_sendViaSpecificPath(tPtr, peer, peer->_paths[i].p, userSpecifiedMtu, now, packet, encrypt, flowId);
				}
			}
			return true;
		}
		else {
			viaPath = peer->getAppropriatePath(now, false, flowId);
			if (! viaPath) {
				peer->tryMemorizedPath(tPtr, now);	 // periodically attempt memorized or statically defined paths, if any are known
				const SharedPtr<Peer> relay(RR->topology->getUpstreamPeer(nwid));
				if ((! relay) || (! (viaPath = relay->getAppropriatePath(now, false, flowId)))) {
					if (! (viaPath = peer->getAppropriatePath(now, true, flowId))) {
						return false;
					}
				}
			}
			if (viaPath) {
				uint16_t userSpecifiedMtu = viaPath->mtu();
				_sendViaSpecificPath(tPtr, peer, viaPath, userSpecifiedMtu, now, packet, encrypt, flowId);
				return true;
			}
		}
	}
	return false;
}

void Switch::_sendViaSpecificPath(void* tPtr, SharedPtr<Peer> peer, SharedPtr<Path> viaPath, uint16_t userSpecifiedMtu, int64_t now, Packet& packet, bool encrypt, int32_t flowId)
{
	unsigned int mtu = ZT_DEFAULT_PHYSMTU;
	uint64_t trustedPathId = 0;
	RR->topology->getOutboundPathInfo(viaPath->address(), mtu, trustedPathId);

	if (userSpecifiedMtu > 0) {
		mtu = userSpecifiedMtu;
	}
	unsigned int chunkSize = std::min(packet.size(), mtu);
	packet.setFragmented(chunkSize < packet.size());

	if (trustedPathId) {
		packet.setTrusted(trustedPathId);
	}
	else {
		if (! packet.isEncrypted()) {
			packet.armor(peer->key(), encrypt, false, peer->aesKeysIfSupported(), peer->identity());
		}
		RR->node->expectReplyTo(packet.packetId());
	}

	peer->recordOutgoingPacket(viaPath, packet.packetId(), packet.payloadLength(), packet.verb(), flowId, now);

	if (viaPath->send(RR, tPtr, packet.data(), chunkSize, now)) {
		if (chunkSize < packet.size()) {
			// Too big for one packet, fragment the rest
			unsigned int fragStart = chunkSize;
			unsigned int remaining = packet.size() - chunkSize;
			unsigned int fragsRemaining = (remaining / (mtu - ZT_PROTO_MIN_FRAGMENT_LENGTH));
			if ((fragsRemaining * (mtu - ZT_PROTO_MIN_FRAGMENT_LENGTH)) < remaining) {
				++fragsRemaining;
			}
			const unsigned int totalFragments = fragsRemaining + 1;

			for (unsigned int fno = 1; fno < totalFragments; ++fno) {
				chunkSize = std::min(remaining, (unsigned int)(mtu - ZT_PROTO_MIN_FRAGMENT_LENGTH));
				Packet::Fragment frag(packet, fragStart, chunkSize, fno, totalFragments);
				viaPath->send(RR, tPtr, frag.data(), frag.size(), now);
				fragStart += chunkSize;
				remaining -= chunkSize;
			}
		}
	}
}

void Switch::_recordOutgoingPacketMetrics(const Packet& p)
{
	switch (p.verb()) {
		case Packet::VERB_NOP:
			Metrics::pkt_nop_out++;
			break;
		case Packet::VERB_HELLO:
			Metrics::pkt_hello_out++;
			break;
		case Packet::VERB_ERROR:
			Metrics::pkt_error_out++;
			break;
		case Packet::VERB_OK:
			Metrics::pkt_ok_out++;
			break;
		case Packet::VERB_WHOIS:
			Metrics::pkt_whois_out++;
			break;
		case Packet::VERB_RENDEZVOUS:
			Metrics::pkt_rendezvous_out++;
			break;
		case Packet::VERB_FRAME:
			Metrics::pkt_frame_out++;
			break;
		case Packet::VERB_EXT_FRAME:
			Metrics::pkt_ext_frame_out++;
			break;
		case Packet::VERB_ECHO:
			Metrics::pkt_echo_out++;
			break;
		case Packet::VERB_MULTICAST_LIKE:
			Metrics::pkt_multicast_like_out++;
			break;
		case Packet::VERB_NETWORK_CREDENTIALS:
			Metrics::pkt_network_credentials_out++;
			break;
		case Packet::VERB_NETWORK_CONFIG_REQUEST:
			Metrics::pkt_network_config_request_out++;
			break;
		case Packet::VERB_NETWORK_CONFIG:
			Metrics::pkt_network_config_out++;
			break;
		case Packet::VERB_MULTICAST_GATHER:
			Metrics::pkt_multicast_gather_out++;
			break;
		case Packet::VERB_MULTICAST_FRAME:
			Metrics::pkt_multicast_frame_out++;
			break;
		case Packet::VERB_PUSH_DIRECT_PATHS:
			Metrics::pkt_push_direct_paths_out++;
			break;
		case Packet::VERB_ACK:
			Metrics::pkt_ack_out++;
			break;
		case Packet::VERB_QOS_MEASUREMENT:
			Metrics::pkt_qos_out++;
			break;
		case Packet::VERB_USER_MESSAGE:
			Metrics::pkt_user_message_out++;
			break;
		case Packet::VERB_REMOTE_TRACE:
			Metrics::pkt_remote_trace_out++;
			break;
		case Packet::VERB_PATH_NEGOTIATION_REQUEST:
			Metrics::pkt_path_negotiation_request_out++;
			break;
	}
}

}	// namespace ZeroTier