ZeroTierOne/core/VL1.cpp

/*
 * Copyright (c)2013-2020 ZeroTier, Inc.
 *
 * Use of this software is governed by the Business Source License included
 * in the LICENSE.TXT file in the project's root directory.
 *
 * Change Date: 2024-01-01
 *
 * On the date above, in accordance with the Business Source License, use
 * of this software will be governed by version 2.0 of the Apache License.
 */
/****/

#include "VL1.hpp"
#include "RuntimeEnvironment.hpp"
#include "Node.hpp"
#include "Topology.hpp"
#include "VL2.hpp"
#include "AES.hpp"
#include "Salsa20.hpp"
#include "LZ4.hpp"
#include "Poly1305.hpp"
#include "SHA512.hpp"
#include "Identity.hpp"
#include "SelfAwareness.hpp"
#include "Peer.hpp"
#include "Path.hpp"
#include "Expect.hpp"

namespace ZeroTier {

namespace {

ZT_INLINE const Identity &identityFromPeerPtr(const SharedPtr< Peer > &p)
{
	return (p) ? p->identity() : Identity::NIL;
}

struct p_SalsaPolyCopyFunction
{
	Salsa20 s20;
	Poly1305 poly1305;
	unsigned int hdrRemaining;

	ZT_INLINE p_SalsaPolyCopyFunction(const void *salsaKey, const void *salsaIv) :
		s20(salsaKey, salsaIv),
		poly1305(),
		hdrRemaining(ZT_PROTO_PACKET_ENCRYPTED_SECTION_START)
	{
		uint8_t macKey[ZT_POLY1305_KEY_SIZE];
		s20.crypt12(Utils::ZERO256, macKey, ZT_POLY1305_KEY_SIZE);
		poly1305.init(macKey);
	}

	ZT_INLINE void operator()(void *dest, const void *src, unsigned int len) noexcept
	{
		if (hdrRemaining != 0) {
			unsigned int hdrBytes = (len > hdrRemaining) ? hdrRemaining : len;
			Utils::copy(dest, src, hdrBytes);
			hdrRemaining -= hdrBytes;
			dest = reinterpret_cast<uint8_t *>(dest) + hdrBytes;
			src = reinterpret_cast<const uint8_t *>(src) + hdrBytes;
			len -= hdrBytes;
		}
		poly1305.update(src, len);
		s20.crypt12(src, dest, len);
	}
};

struct p_PolyCopyFunction
{
	Poly1305 poly1305;
	unsigned int hdrRemaining;

	ZT_INLINE p_PolyCopyFunction(const void *salsaKey, const void *salsaIv) :
		poly1305(),
		hdrRemaining(ZT_PROTO_PACKET_ENCRYPTED_SECTION_START)
	{
		uint8_t macKey[ZT_POLY1305_KEY_SIZE];
		Salsa20(salsaKey, salsaIv).crypt12(Utils::ZERO256, macKey, ZT_POLY1305_KEY_SIZE);
		poly1305.init(macKey);
	}

	ZT_INLINE void operator()(void *dest, const void *src, unsigned int len) noexcept
	{
		if (hdrRemaining != 0) {
			unsigned int hdrBytes = (len > hdrRemaining) ? hdrRemaining : len;
			Utils::copy(dest, src, hdrBytes);
			hdrRemaining -= hdrBytes;
			dest = reinterpret_cast<uint8_t *>(dest) + hdrBytes;
			src = reinterpret_cast<const uint8_t *>(src) + hdrBytes;
			len -= hdrBytes;
		}
		poly1305.update(src, len);
		Utils::copy(dest, src, len);
	}
};

} // anonymous namespace

VL1::VL1(const RuntimeEnvironment *renv) :
	RR(renv)
{
}

void VL1::onRemotePacket(void *const tPtr, const int64_t localSocket, const InetAddress &fromAddr, SharedPtr< Buf > &data, const unsigned int len) noexcept
{
	const SharedPtr< Path > path(RR->topology->path(localSocket, fromAddr));
	const int64_t now = RR->node->now();

	ZT_SPEW("%u bytes from %s (local socket %lld)", len, fromAddr.toString().c_str(), localSocket);
	path->received(now, len);

	// NOTE: likely/unlikely are used here to highlight the most common code path
	// for valid data packets. This may allow the compiler to generate very slightly
	// faster code for that path.

	try {
		if (unlikely(len < ZT_PROTO_MIN_FRAGMENT_LENGTH))
			return;

		static_assert((ZT_PROTO_PACKET_ID_INDEX + sizeof(uint64_t)) < ZT_PROTO_MIN_FRAGMENT_LENGTH, "overflow");
		const uint64_t packetId = Utils::loadAsIsEndian< uint64_t >(data->unsafeData + ZT_PROTO_PACKET_ID_INDEX);

		static_assert((ZT_PROTO_PACKET_DESTINATION_INDEX + ZT_ADDRESS_LENGTH) < ZT_PROTO_MIN_FRAGMENT_LENGTH, "overflow");
		const Address destination(data->unsafeData + ZT_PROTO_PACKET_DESTINATION_INDEX);
		if (destination != RR->identity.address()) {
			m_relay(tPtr, path, destination, data, len);
			return;
		}

		// ----------------------------------------------------------------------------------------------------------------
		// If we made it this far, the packet is at least MIN_FRAGMENT_LENGTH and is addressed to this node's ZT address
		// ----------------------------------------------------------------------------------------------------------------

		Buf::PacketVector pktv;

		static_assert(ZT_PROTO_PACKET_FRAGMENT_INDICATOR_INDEX <= ZT_PROTO_MIN_FRAGMENT_LENGTH, "overflow");
		if (data->unsafeData[ZT_PROTO_PACKET_FRAGMENT_INDICATOR_INDEX] == ZT_PROTO_PACKET_FRAGMENT_INDICATOR) {
			// This looks like a fragment (excluding the head) of a larger packet.
			static_assert(ZT_PROTO_PACKET_FRAGMENT_COUNTS < ZT_PROTO_MIN_FRAGMENT_LENGTH, "overflow");
			const unsigned int totalFragments = (data->unsafeData[ZT_PROTO_PACKET_FRAGMENT_COUNTS] >> 4U) & 0x0fU;
			const unsigned int fragmentNo = data->unsafeData[ZT_PROTO_PACKET_FRAGMENT_COUNTS] & 0x0fU;
			switch (m_inputPacketAssembler.assemble(
				packetId,
				pktv,
				data,
				ZT_PROTO_PACKET_FRAGMENT_PAYLOAD_START_AT,
				len - ZT_PROTO_PACKET_FRAGMENT_PAYLOAD_START_AT,
				fragmentNo,
				totalFragments,
				now,
				path)) {
				case Defragmenter< ZT_MAX_PACKET_FRAGMENTS >::COMPLETE:
					break;
				default:
					//case Defragmenter<ZT_MAX_PACKET_FRAGMENTS>::OK:
					//case Defragmenter<ZT_MAX_PACKET_FRAGMENTS>::ERR_DUPLICATE_FRAGMENT:
					//case Defragmenter<ZT_MAX_PACKET_FRAGMENTS>::ERR_INVALID_FRAGMENT:
					//case Defragmenter<ZT_MAX_PACKET_FRAGMENTS>::ERR_TOO_MANY_FRAGMENTS_FOR_PATH:
					//case Defragmenter<ZT_MAX_PACKET_FRAGMENTS>::ERR_OUT_OF_MEMORY:
					return;
			}
		} else {
			if (unlikely(len < ZT_PROTO_MIN_PACKET_LENGTH))
				return;
			static_assert(ZT_PROTO_PACKET_FLAGS_INDEX < ZT_PROTO_MIN_PACKET_LENGTH, "overflow");
			if ((data->unsafeData[ZT_PROTO_PACKET_FLAGS_INDEX] & ZT_PROTO_FLAG_FRAGMENTED) != 0) {
				// This is the head of a series of fragments that we may or may not already have.
				switch (m_inputPacketAssembler.assemble(
					packetId,
					pktv,
					data,
					0, // fragment index is 0 since this is the head
					len,
					0, // always the zero'eth fragment
					0, // this is specified in fragments, not in the head
					now,
					path)) {
					case Defragmenter< ZT_MAX_PACKET_FRAGMENTS >::COMPLETE:
						break;
					default:
						//case Defragmenter<ZT_MAX_PACKET_FRAGMENTS>::OK:
						//case Defragmenter<ZT_MAX_PACKET_FRAGMENTS>::ERR_DUPLICATE_FRAGMENT:
						//case Defragmenter<ZT_MAX_PACKET_FRAGMENTS>::ERR_INVALID_FRAGMENT:
						//case Defragmenter<ZT_MAX_PACKET_FRAGMENTS>::ERR_TOO_MANY_FRAGMENTS_FOR_PATH:
						//case Defragmenter<ZT_MAX_PACKET_FRAGMENTS>::ERR_OUT_OF_MEMORY:
						return;
				}
			} else {
				// This is a single whole packet with no fragments.
				Buf::Slice s = pktv.push();
				s.b.swap(data);
				s.s = 0;
				s.e = len;
			}
		}

		// ----------------------------------------------------------------------------------------------------------------
		// If we made it this far without returning, a packet is fully assembled and ready to process.
		// ----------------------------------------------------------------------------------------------------------------

		const uint8_t *const hdr = pktv[0].b->unsafeData + pktv[0].s;
		static_assert((ZT_PROTO_PACKET_SOURCE_INDEX + ZT_ADDRESS_LENGTH) < ZT_PROTO_MIN_PACKET_LENGTH, "overflow");
		const Address source(hdr + ZT_PROTO_PACKET_SOURCE_INDEX);
		static_assert(ZT_PROTO_PACKET_FLAGS_INDEX < ZT_PROTO_MIN_PACKET_LENGTH, "overflow");
		const uint8_t hops = hdr[ZT_PROTO_PACKET_FLAGS_INDEX] & ZT_PROTO_FLAG_FIELD_HOPS_MASK;
		const uint8_t cipher = (hdr[ZT_PROTO_PACKET_FLAGS_INDEX] >> 3U) & 3U;

		SharedPtr< Buf > pkt(new Buf());
		int pktSize = 0;

		static_assert(ZT_PROTO_PACKET_VERB_INDEX < ZT_PROTO_MIN_PACKET_LENGTH, "overflow");
		if (unlikely(((cipher == ZT_PROTO_CIPHER_SUITE__POLY1305_NONE) || (cipher == ZT_PROTO_CIPHER_SUITE__NONE)) && ((hdr[ZT_PROTO_PACKET_VERB_INDEX] & ZT_PROTO_VERB_MASK) == Protocol::VERB_HELLO))) {
			// Handle unencrypted HELLO packets.
			pktSize = pktv.mergeCopy(*pkt);
			if (unlikely(pktSize < ZT_PROTO_MIN_PACKET_LENGTH)) {
				ZT_SPEW("discarding packet %.16llx from %s(%s): assembled packet size: %d", packetId, source.toString().c_str(), fromAddr.toString().c_str(), pktSize);
				return;
			}
			const SharedPtr< Peer > peer(m_HELLO(tPtr, path, *pkt, pktSize));
			if (likely(peer))
				peer->received(tPtr, path, hops, packetId, pktSize - ZT_PROTO_PACKET_PAYLOAD_START, Protocol::VERB_HELLO, Protocol::VERB_NOP);
			return;
		}

		// This remains zero if authentication fails. Otherwise it gets set to a bit mask
		// indicating authentication and other security flags like encryption and forward
		// secrecy status.
		unsigned int auth = 0;

		SharedPtr< Peer > peer(RR->topology->peer(tPtr, source));
		if (likely(peer)) {
			switch (cipher) {

				case ZT_PROTO_CIPHER_SUITE__POLY1305_NONE: {
					uint8_t perPacketKey[ZT_SALSA20_KEY_SIZE];
					Protocol::salsa2012DeriveKey(peer->rawIdentityKey(), perPacketKey, *pktv[0].b, pktv.totalSize());
					p_PolyCopyFunction s20cf(perPacketKey, &packetId);

					pktSize = pktv.mergeMap< p_PolyCopyFunction & >(*pkt, ZT_PROTO_PACKET_ENCRYPTED_SECTION_START, s20cf);
					if (unlikely(pktSize < ZT_PROTO_MIN_PACKET_LENGTH)) {
						ZT_SPEW("discarding packet %.16llx from %s(%s): assembled packet size: %d", packetId, source.toString().c_str(), fromAddr.toString().c_str(), pktSize);
						return;
					}

					uint64_t mac[2];
					s20cf.poly1305.finish(mac);
					static_assert((ZT_PROTO_PACKET_MAC_INDEX + 8) < ZT_PROTO_MIN_PACKET_LENGTH, "overflow");
					if (unlikely(Utils::loadAsIsEndian< uint64_t >(hdr + ZT_PROTO_PACKET_MAC_INDEX) != mac[0])) {
						ZT_SPEW("discarding packet %.16llx from %s(%s): packet MAC failed (none/poly1305)", packetId, source.toString().c_str(), fromAddr.toString().c_str());
						RR->t->incomingPacketDropped(tPtr, 0xcc89c812, packetId, 0, peer->identity(), path->address(), hops, Protocol::VERB_NOP, ZT_TRACE_PACKET_DROP_REASON_MAC_FAILED);
						return;
					}

					auth = ZT_VL1_AUTH_RESULT_FLAG_AUTHENTICATED;
				}
					break;

				case ZT_PROTO_CIPHER_SUITE__POLY1305_SALSA2012: {
					uint8_t perPacketKey[ZT_SALSA20_KEY_SIZE];
					Protocol::salsa2012DeriveKey(peer->rawIdentityKey(), perPacketKey, *pktv[0].b, pktv.totalSize());
					p_SalsaPolyCopyFunction s20cf(perPacketKey, &packetId);

					pktSize = pktv.mergeMap< p_SalsaPolyCopyFunction & >(*pkt, ZT_PROTO_PACKET_ENCRYPTED_SECTION_START, s20cf);
					if (unlikely(pktSize < ZT_PROTO_MIN_PACKET_LENGTH)) {
						ZT_SPEW("discarding packet %.16llx from %s(%s): assembled packet size: %d", packetId, source.toString().c_str(), fromAddr.toString().c_str(), pktSize);
						return;
					}

					uint64_t mac[2];
					s20cf.poly1305.finish(mac);
					static_assert((ZT_PROTO_PACKET_MAC_INDEX + 8) < ZT_PROTO_MIN_PACKET_LENGTH, "overflow");
					if (unlikely(Utils::loadAsIsEndian< uint64_t >(hdr + ZT_PROTO_PACKET_MAC_INDEX) != mac[0])) {
						ZT_SPEW("discarding packet %.16llx from %s(%s): packet MAC failed (salsa/poly1305)", packetId, source.toString().c_str(), fromAddr.toString().c_str());
						RR->t->incomingPacketDropped(tPtr, 0xcc89c812, packetId, 0, peer->identity(), path->address(), hops, Protocol::VERB_NOP, ZT_TRACE_PACKET_DROP_REASON_MAC_FAILED);
						return;
					}

					auth = ZT_VL1_AUTH_RESULT_FLAG_AUTHENTICATED | ZT_VL1_AUTH_RESULT_FLAG_ENCRYPTED;
				}
					break;

				case ZT_PROTO_CIPHER_SUITE__NONE: {
					// TODO
				}
					break;

				case ZT_PROTO_CIPHER_SUITE__AES_GMAC_SIV: {
					// TODO
				}
					break;

				default:
					RR->t->incomingPacketDropped(tPtr, 0x5b001099, packetId, 0, identityFromPeerPtr(peer), path->address(), hops, Protocol::VERB_NOP, ZT_TRACE_PACKET_DROP_REASON_INVALID_OBJECT);
					return;
			}
		}

		if (likely(auth != 0)) {
			// If authentication was successful go on and process the packet.

			if (unlikely(pktSize < ZT_PROTO_MIN_PACKET_LENGTH)) {
				ZT_SPEW("discarding packet %.16llx from %s(%s): assembled packet size %d is smaller than minimum packet length", packetId, source.toString().c_str(), fromAddr.toString().c_str(), pktSize);
				return;
			}

			// TODO: should take instance ID into account here once that is fully implemented.
			if (unlikely(peer->deduplicateIncomingPacket(packetId))) {
				ZT_SPEW("discarding packet %.16llx from %s(%s): duplicate!", packetId, source.toString().c_str(), fromAddr.toString().c_str());
				return;
			}

			static_assert(ZT_PROTO_PACKET_VERB_INDEX < ZT_PROTO_MIN_PACKET_LENGTH, "overflow");
			const uint8_t verbFlags = pkt->unsafeData[ZT_PROTO_PACKET_VERB_INDEX];
			const Protocol::Verb verb = (Protocol::Verb)(verbFlags & ZT_PROTO_VERB_MASK);

			// Decompress packet payload if compressed. For additional safety decompression is
			// only performed on packets whose MACs have already been validated. (Only HELLO is
			// sent without this, and HELLO doesn't benefit from compression.)
			if (((verbFlags & ZT_PROTO_VERB_FLAG_COMPRESSED) != 0) && (pktSize > ZT_PROTO_PACKET_PAYLOAD_START)) {
				SharedPtr< Buf > dec(new Buf());
				Utils::copy< ZT_PROTO_PACKET_PAYLOAD_START >(dec->unsafeData, pkt->unsafeData);
				const int uncompressedLen = LZ4_decompress_safe(
					reinterpret_cast<const char *>(pkt->unsafeData + ZT_PROTO_PACKET_PAYLOAD_START),
					reinterpret_cast<char *>(dec->unsafeData + ZT_PROTO_PACKET_PAYLOAD_START),
					pktSize - ZT_PROTO_PACKET_PAYLOAD_START,
					ZT_BUF_MEM_SIZE - ZT_PROTO_PACKET_PAYLOAD_START);
				if (likely((uncompressedLen >= 0) && (uncompressedLen <= (ZT_BUF_MEM_SIZE - ZT_PROTO_PACKET_PAYLOAD_START)))) {
					pkt.swap(dec);
					ZT_SPEW("decompressed packet: %d -> %d", pktSize, ZT_PROTO_PACKET_PAYLOAD_START + uncompressedLen);
					pktSize = ZT_PROTO_PACKET_PAYLOAD_START + uncompressedLen;
				} else {
					RR->t->incomingPacketDropped(tPtr, 0xee9e4392, packetId, 0, identityFromPeerPtr(peer), path->address(), hops, verb, ZT_TRACE_PACKET_DROP_REASON_INVALID_COMPRESSED_DATA);
					return;
				}
			}

			ZT_SPEW("%s from %s(%s) (%d bytes)", Protocol::verbName(verb), source.toString().c_str(), fromAddr.toString().c_str(), pktSize);

			// NOTE: HELLO is normally sent in the clear (in terms of our usual AEAD modes) and is handled
			// above. We will try to process it here, but if so it'll still get re-authenticated via HELLO's
			// own internal authentication logic as usual. It would be abnormal to make it here with HELLO
			// but not invalid.

			Protocol::Verb inReVerb = Protocol::VERB_NOP;
			bool ok = true;
			switch (verb) {
				case Protocol::VERB_NOP:
					break;
				case Protocol::VERB_HELLO:
					ok = (bool)(m_HELLO(tPtr, path, *pkt, pktSize));
					break;
				case Protocol::VERB_ERROR:
					ok = m_ERROR(tPtr, packetId, auth, path, peer, *pkt, pktSize, inReVerb);
					break;
				case Protocol::VERB_OK:
					ok = m_OK(tPtr, packetId, auth, path, peer, *pkt, pktSize, inReVerb);
					break;
				case Protocol::VERB_WHOIS:
					ok = m_WHOIS(tPtr, packetId, auth, path, peer, *pkt, pktSize);
					break;
				case Protocol::VERB_RENDEZVOUS:
					ok = m_RENDEZVOUS(tPtr, packetId, auth, path, peer, *pkt, pktSize);
					break;
				case Protocol::VERB_FRAME:
					ok = RR->vl2->m_FRAME(tPtr, packetId, auth, path, peer, *pkt, pktSize);
					break;
				case Protocol::VERB_EXT_FRAME:
					ok = RR->vl2->m_EXT_FRAME(tPtr, packetId, auth, path, peer, *pkt, pktSize);
					break;
				case Protocol::VERB_ECHO:
					ok = m_ECHO(tPtr, packetId, auth, path, peer, *pkt, pktSize);
					break;
				case Protocol::VERB_MULTICAST_LIKE:
					ok = RR->vl2->m_MULTICAST_LIKE(tPtr, packetId, auth, path, peer, *pkt, pktSize);
					break;
				case Protocol::VERB_NETWORK_CREDENTIALS:
					ok = RR->vl2->m_NETWORK_CREDENTIALS(tPtr, packetId, auth, path, peer, *pkt, pktSize);
					break;
				case Protocol::VERB_NETWORK_CONFIG_REQUEST:
					ok = RR->vl2->m_NETWORK_CONFIG_REQUEST(tPtr, packetId, auth, path, peer, *pkt, pktSize);
					break;
				case Protocol::VERB_NETWORK_CONFIG:
					ok = RR->vl2->m_NETWORK_CONFIG(tPtr, packetId, auth, path, peer, *pkt, pktSize);
					break;
				case Protocol::VERB_MULTICAST_GATHER:
					ok = RR->vl2->m_MULTICAST_GATHER(tPtr, packetId, auth, path, peer, *pkt, pktSize);
					break;
				case Protocol::VERB_MULTICAST_FRAME_deprecated:
					ok = RR->vl2->m_MULTICAST_FRAME_deprecated(tPtr, packetId, auth, path, peer, *pkt, pktSize);
					break;
				case Protocol::VERB_PUSH_DIRECT_PATHS:
					ok = m_PUSH_DIRECT_PATHS(tPtr, packetId, auth, path, peer, *pkt, pktSize);
					break;
				case Protocol::VERB_USER_MESSAGE:
					ok = m_USER_MESSAGE(tPtr, packetId, auth, path, peer, *pkt, pktSize);
					break;
				case Protocol::VERB_MULTICAST:
					ok = RR->vl2->m_MULTICAST(tPtr, packetId, auth, path, peer, *pkt, pktSize);
					break;
				case Protocol::VERB_ENCAP:
					ok = m_ENCAP(tPtr, packetId, auth, path, peer, *pkt, pktSize);
					break;

				default:
					RR->t->incomingPacketDropped(tPtr, 0xeeeeeff0, packetId, 0, identityFromPeerPtr(peer), path->address(), hops, verb, ZT_TRACE_PACKET_DROP_REASON_UNRECOGNIZED_VERB);
					break;
			}
			if (likely(ok))
				peer->received(tPtr, path, hops, packetId, pktSize - ZT_PROTO_PACKET_PAYLOAD_START, verb, inReVerb);
		} else {
			// If decryption and authentication were not successful, try to look up identities.
			// This is rate limited by virtue of the retry rate limit timer.
			if (pktSize <= 0)
				pktSize = pktv.mergeCopy(*pkt);
			if (likely(pktSize >= ZT_PROTO_MIN_PACKET_LENGTH)) {
				ZT_SPEW("authentication failed or no peers match, queueing WHOIS for %s", source.toString().c_str());
				bool sendPending;
				{
					Mutex::Lock wl(m_whoisQueue_l);
					p_WhoisQueueItem &wq = m_whoisQueue[source];
					const unsigned int wpidx = wq.waitingPacketCount++ % ZT_VL1_MAX_WHOIS_WAITING_PACKETS;
					wq.waitingPacketSize[wpidx] = (unsigned int)pktSize;
					wq.waitingPacket[wpidx] = pkt;
					sendPending = (now - wq.lastRetry) >= ZT_WHOIS_RETRY_DELAY;
				}
				if (sendPending)
					m_sendPendingWhois(tPtr, now);
			}
		}
	} catch (...) {
		RR->t->unexpectedError(tPtr, 0xea1b6dea, "unexpected exception in onRemotePacket() parsing packet from %s", path->address().toString().c_str());
	}
}

void VL1::m_relay(void *tPtr, const SharedPtr< Path > &path, Address destination, SharedPtr< Buf > &pkt, int pktSize)
{
}

void VL1::m_sendPendingWhois(void *tPtr, int64_t now)
{
	const SharedPtr< Peer > root(RR->topology->root());
	if (unlikely(!root))
		return;
	const SharedPtr< Path > rootPath(root->path(now));
	if (unlikely(!rootPath))
		return;

	Vector< Address > toSend;
	{
		Mutex::Lock wl(m_whoisQueue_l);
		for (Map< Address, p_WhoisQueueItem >::iterator wi(m_whoisQueue.begin()); wi != m_whoisQueue.end(); ++wi) {
			if ((now - wi->second.lastRetry) >= ZT_WHOIS_RETRY_DELAY) {
				wi->second.lastRetry = now;
				++wi->second.retries;
				toSend.push_back(wi->first);
			}
		}
	}

	if (!toSend.empty()) {
		const SharedPtr< SymmetricKey > key(root->key());
		uint8_t outp[ZT_DEFAULT_UDP_MTU - ZT_PROTO_MIN_PACKET_LENGTH];
		Vector< Address >::iterator a(toSend.begin());
		while (a != toSend.end()) {
			const uint64_t packetId = key->nextMessage(RR->identity.address(), root->address());
			int p = Protocol::newPacket(outp, packetId, root->address(), RR->identity.address(), Protocol::VERB_WHOIS);
			while ((a != toSend.end()) && (p < (sizeof(outp) - ZT_ADDRESS_LENGTH))) {
				a->copyTo(outp + p);
				++a;
				p += ZT_ADDRESS_LENGTH;
			}
			Protocol::armor(outp, p, key, root->cipher());
			RR->expect->sending(packetId, now);
			root->send(tPtr, now, outp, p, rootPath);
		}
	}
}

SharedPtr< Peer > VL1::m_HELLO(void *tPtr, const SharedPtr< Path > &path, Buf &pkt, int packetSize)
{
	const uint64_t packetId = Utils::loadAsIsEndian< uint64_t >(pkt.unsafeData + ZT_PROTO_PACKET_ID_INDEX);
	const uint64_t mac = Utils::loadAsIsEndian< uint64_t >(pkt.unsafeData + ZT_PROTO_PACKET_MAC_INDEX);
	const uint8_t hops = pkt.unsafeData[ZT_PROTO_PACKET_FLAGS_INDEX] & ZT_PROTO_FLAG_FIELD_HOPS_MASK;

	const uint8_t protoVersion = pkt.lI8< ZT_PROTO_PACKET_PAYLOAD_START >();
	if (unlikely(protoVersion < ZT_PROTO_VERSION_MIN)) {
		RR->t->incomingPacketDropped(tPtr, 0x907a9891, packetId, 0, Identity::NIL, path->address(), hops, Protocol::VERB_HELLO, ZT_TRACE_PACKET_DROP_REASON_PEER_TOO_OLD);
		return SharedPtr< Peer >();
	}
	const unsigned int versionMajor = pkt.lI8< ZT_PROTO_PACKET_PAYLOAD_START + 1 >();
	const unsigned int versionMinor = pkt.lI8< ZT_PROTO_PACKET_PAYLOAD_START + 2 >();
	const unsigned int versionRev = pkt.lI16< ZT_PROTO_PACKET_PAYLOAD_START + 3 >();
	const uint64_t timestamp = pkt.lI64< ZT_PROTO_PACKET_PAYLOAD_START + 5 >();

	int ii = ZT_PROTO_PACKET_PAYLOAD_START + 13;

	// Get identity and verify that it matches the sending address in the packet.
	Identity id;
	if (unlikely(pkt.rO(ii, id) < 0)) {
		RR->t->incomingPacketDropped(tPtr, 0x707a9810, packetId, 0, Identity::NIL, path->address(), hops, Protocol::VERB_HELLO, ZT_TRACE_PACKET_DROP_REASON_INVALID_OBJECT);
		return SharedPtr< Peer >();
	}
	if (unlikely(id.address() != Address(pkt.unsafeData + ZT_PROTO_PACKET_SOURCE_INDEX))) {
		RR->t->incomingPacketDropped(tPtr, 0x707a9010, packetId, 0, Identity::NIL, path->address(), hops, Protocol::VERB_HELLO, ZT_TRACE_PACKET_DROP_REASON_MAC_FAILED);
		return SharedPtr< Peer >();
	}

	// Get the peer that matches this identity, or learn a new one if we don't know it.
	SharedPtr< Peer > peer(RR->topology->peer(tPtr, id.address(), true));
	if (peer) {
		if (unlikely(peer->identity() != id)) {
			RR->t->incomingPacketDropped(tPtr, 0x707a9891, packetId, 0, identityFromPeerPtr(peer), path->address(), hops, Protocol::VERB_HELLO, ZT_TRACE_PACKET_DROP_REASON_MAC_FAILED);
			return SharedPtr< Peer >();
		}
		if (unlikely(peer->deduplicateIncomingPacket(packetId))) {
			ZT_SPEW("discarding packet %.16llx from %s(%s): duplicate!", packetId, id.address().toString().c_str(), path->address().toString().c_str());
			return SharedPtr< Peer >();
		}
	} else {
		if (unlikely(!id.locallyValidate())) {
			RR->t->incomingPacketDropped(tPtr, 0x707a9892, packetId, 0, identityFromPeerPtr(peer), path->address(), hops, Protocol::VERB_HELLO, ZT_TRACE_PACKET_DROP_REASON_INVALID_OBJECT);
			return SharedPtr< Peer >();
		}
		peer.set(new Peer(RR));
		if (unlikely(!peer->init(id))) {
			RR->t->incomingPacketDropped(tPtr, 0x707a9893, packetId, 0, identityFromPeerPtr(peer), path->address(), hops, Protocol::VERB_HELLO, ZT_TRACE_PACKET_DROP_REASON_UNSPECIFIED);
			return SharedPtr< Peer >();
		}
		peer = RR->topology->add(tPtr, peer);
	}

	// ------------------------------------------------------------------------------------------------------------------
	// If we made it this far, peer is non-NULL and the identity is valid and matches it.
	// ------------------------------------------------------------------------------------------------------------------

	if (protoVersion >= 11) {
		// V2.x and newer use HMAC-SHA384 for HELLO, which offers a larger security margin
		// to guard key exchange and connection setup than typical AEAD. The packet MAC
		// field is ignored, and eventually it'll be undefined.
		uint8_t hmac[ZT_HMACSHA384_LEN];
		if (unlikely(packetSize < ZT_HMACSHA384_LEN)) {
			RR->t->incomingPacketDropped(tPtr, 0xab9c9891, packetId, 0, identityFromPeerPtr(peer), path->address(), hops, Protocol::VERB_HELLO, ZT_TRACE_PACKET_DROP_REASON_MAC_FAILED);
			return SharedPtr< Peer >();
		}
		packetSize -= ZT_HMACSHA384_LEN;
		pkt.unsafeData[ZT_PROTO_PACKET_FLAGS_INDEX] &= ~ZT_PROTO_FLAG_FIELD_HOPS_MASK; // mask hops to 0
		Utils::storeAsIsEndian< uint64_t >(pkt.unsafeData + ZT_PROTO_PACKET_MAC_INDEX, 0); // set MAC field to 0
		HMACSHA384(peer->identityHelloHmacKey(), pkt.unsafeData, packetSize, hmac);
		if (unlikely(!Utils::secureEq(hmac, pkt.unsafeData + packetSize, ZT_HMACSHA384_LEN))) {
			RR->t->incomingPacketDropped(tPtr, 0x707a9891, packetId, 0, identityFromPeerPtr(peer), path->address(), hops, Protocol::VERB_HELLO, ZT_TRACE_PACKET_DROP_REASON_MAC_FAILED);
			return SharedPtr< Peer >();
		}
	} else {
		// Older versions use Poly1305 MAC (but no whole packet encryption) for HELLO.
		if (likely(packetSize > ZT_PROTO_PACKET_ENCRYPTED_SECTION_START)) {
			uint8_t perPacketKey[ZT_SALSA20_KEY_SIZE];
			Protocol::salsa2012DeriveKey(peer->rawIdentityKey(), perPacketKey, pkt, packetSize);
			uint8_t macKey[ZT_POLY1305_KEY_SIZE];
			Salsa20(perPacketKey, &packetId).crypt12(Utils::ZERO256, macKey, ZT_POLY1305_KEY_SIZE);
			Poly1305 poly1305(macKey);
			poly1305.update(pkt.unsafeData + ZT_PROTO_PACKET_ENCRYPTED_SECTION_START, packetSize - ZT_PROTO_PACKET_ENCRYPTED_SECTION_START);
			uint64_t polyMac[2];
			poly1305.finish(polyMac);
			if (unlikely(mac != polyMac[0])) {
				RR->t->incomingPacketDropped(tPtr, 0x11bfff82, packetId, 0, id, path->address(), hops, Protocol::VERB_NOP, ZT_TRACE_PACKET_DROP_REASON_MAC_FAILED);
				return SharedPtr< Peer >();
			}
		} else {
			RR->t->incomingPacketDropped(tPtr, 0x11bfff81, packetId, 0, id, path->address(), hops, Protocol::VERB_NOP, ZT_TRACE_PACKET_DROP_REASON_MAC_FAILED);
			return SharedPtr< Peer >();
		}
	}

	// ------------------------------------------------------------------------------------------------------------------
	// This far means we passed MAC (Poly1305 or HMAC-SHA384 for newer peers)
	// ------------------------------------------------------------------------------------------------------------------

	InetAddress sentTo;
	if (unlikely(pkt.rO(ii, sentTo) < 0)) {
		RR->t->incomingPacketDropped(tPtr, 0x707a9811, packetId, 0, identityFromPeerPtr(peer), path->address(), hops, Protocol::VERB_HELLO, ZT_TRACE_PACKET_DROP_REASON_INVALID_OBJECT);
		return SharedPtr< Peer >();
	}

	const SharedPtr< SymmetricKey > key(peer->identityKey());

	if (protoVersion >= 11) {
		// V2.x and newer supports an encrypted section and has a new OK format.
		ii += 4; // skip reserved field
		if (likely((ii + 12) < packetSize)) {
			AES::CTR ctr(peer->identityHelloDictionaryEncryptionCipher());
			const uint8_t *const ctrNonce = pkt.unsafeData + ii;
			ii += 12;
			ctr.init(ctrNonce, 0, pkt.unsafeData + ii);
			ctr.crypt(pkt.unsafeData + ii, packetSize - ii);
			ctr.finish();

			ii += 2; // skip reserved field
			const unsigned int dictSize = pkt.rI16(ii);
			if (unlikely((ii + dictSize) > packetSize)) {
				RR->t->incomingPacketDropped(tPtr, 0x707a9815, packetId, 0, identityFromPeerPtr(peer), path->address(), hops, Protocol::VERB_HELLO, ZT_TRACE_PACKET_DROP_REASON_INVALID_OBJECT);
				return peer;
			}
			Dictionary md;
			if (!md.decode(pkt.unsafeData + ii, dictSize)) {
				RR->t->incomingPacketDropped(tPtr, 0x707a9816, packetId, 0, identityFromPeerPtr(peer), path->address(), hops, Protocol::VERB_HELLO, ZT_TRACE_PACKET_DROP_REASON_INVALID_OBJECT);
				return peer;
			}

			if (!md.empty()) {
				// TODO
			}
		}
	}

	Protocol::newPacket(pkt, key->nextMessage(RR->identity.address(), peer->address()), peer->address(), RR->identity.address(), Protocol::VERB_OK);
	ii = ZT_PROTO_PACKET_PAYLOAD_START;
	pkt.wI8(ii, Protocol::VERB_HELLO);
	pkt.wI64(ii, packetId);
	pkt.wI64(ii, timestamp);
	pkt.wI8(ii, ZT_PROTO_VERSION);
	pkt.wI8(ii, ZEROTIER_VERSION_MAJOR);
	pkt.wI8(ii, ZEROTIER_VERSION_MINOR);
	pkt.wI16(ii, ZEROTIER_VERSION_REVISION);
	pkt.wO(ii, path->address());
	pkt.wI16(ii, 0); // reserved, specifies no "moons" for older versions

	if (protoVersion >= 11) {
		FCV< uint8_t, 1024 > okmd;
		pkt.wI16(ii, (uint16_t)okmd.size());
		pkt.wB(ii, okmd.data(), okmd.size());

		if (unlikely((ii + ZT_HMACSHA384_LEN) > ZT_BUF_MEM_SIZE)) // sanity check, should be impossible
			return SharedPtr< Peer >();

		HMACSHA384(peer->identityHelloHmacKey(), pkt.unsafeData, ii, pkt.unsafeData + ii);
		ii += ZT_HMACSHA384_LEN;
	}

	peer->setRemoteVersion(protoVersion, versionMajor, versionMinor, versionRev);
	peer->send(tPtr, RR->node->now(), pkt.unsafeData, ii, path);
	return peer;
}

bool VL1::m_ERROR(void *tPtr, const uint64_t packetId, const unsigned int auth, const SharedPtr< Path > &path, const SharedPtr< Peer > &peer, Buf &pkt, int packetSize, Protocol::Verb &inReVerb)
{
#if 0
	if (packetSize < (int)sizeof(Protocol::ERROR::Header)) {
		RR->t->incomingPacketDropped(tPtr,0x3beb1947,0,0,identityFromPeerPtr(peer),path->address(),0,Protocol::VERB_ERROR,ZT_TRACE_PACKET_DROP_REASON_MALFORMED_PACKET);
		return false;
	}
	Protocol::ERROR::Header &eh = pkt.as<Protocol::ERROR::Header>();
	inReVerb = (Protocol::Verb)eh.inReVerb;

	const int64_t now = RR->node->now();
	if (!RR->expect->expecting(eh.inRePacketId,now)) {
		RR->t->incomingPacketDropped(tPtr,0x4c1f1ff7,0,0,identityFromPeerPtr(peer),path->address(),0,Protocol::VERB_OK,ZT_TRACE_PACKET_DROP_REASON_REPLY_NOT_EXPECTED);
		return false;
	}

	switch(eh.error) {

		//case Protocol::ERROR_INVALID_REQUEST:
		//case Protocol::ERROR_BAD_PROTOCOL_VERSION:
		//case Protocol::ERROR_CANNOT_DELIVER:
		default:
			break;

		case Protocol::ERROR_OBJ_NOT_FOUND:
			if (eh.inReVerb == Protocol::VERB_NETWORK_CONFIG_REQUEST) {
			}
			break;

		case Protocol::ERROR_UNSUPPORTED_OPERATION:
			if (eh.inReVerb == Protocol::VERB_NETWORK_CONFIG_REQUEST) {
			}
			break;

		case Protocol::ERROR_NEED_MEMBERSHIP_CERTIFICATE:
			break;

		case Protocol::ERROR_NETWORK_ACCESS_DENIED_:
			if (eh.inReVerb == Protocol::VERB_NETWORK_CONFIG_REQUEST) {
			}
			break;

	}
	return true;
#endif
}

bool VL1::m_OK(void *tPtr, const uint64_t packetId, const unsigned int auth, const SharedPtr< Path > &path, const SharedPtr< Peer > &peer, Buf &pkt, int packetSize, Protocol::Verb &inReVerb)
{
	int ii = ZT_PROTO_PACKET_PAYLOAD_START + 13;

	inReVerb = (Protocol::Verb)pkt.rI8(ii);
	const uint64_t inRePacketId = pkt.rI64(ii);
	if (unlikely(Buf::readOverflow(ii, packetSize))) {
		RR->t->incomingPacketDropped(tPtr, 0x4c1f1ff7, packetId, 0, identityFromPeerPtr(peer), path->address(), 0, Protocol::VERB_OK, ZT_TRACE_PACKET_DROP_REASON_MALFORMED_PACKET);
		return false;
	}

	const int64_t now = RR->node->now();
	if (unlikely(!RR->expect->expecting(inRePacketId, now))) {
		RR->t->incomingPacketDropped(tPtr, 0x4c1f1ff8, packetId, 0, identityFromPeerPtr(peer), path->address(), 0, Protocol::VERB_OK, ZT_TRACE_PACKET_DROP_REASON_REPLY_NOT_EXPECTED);
		return false;
	}

	ZT_SPEW("got OK in-re %s (packet ID %.16llx) from %s(%s)", Protocol::verbName(inReVerb), inRePacketId, peer->address().toString().c_str(), path->address().toString().c_str());

	switch (inReVerb) {

		case Protocol::VERB_HELLO:
			break;

		case Protocol::VERB_WHOIS:
			break;

		case Protocol::VERB_NETWORK_CONFIG_REQUEST:
			break;

		case Protocol::VERB_MULTICAST_GATHER:
			break;

	}

	return true;
}

bool VL1::m_WHOIS(void *tPtr, const uint64_t packetId, const unsigned int auth, const SharedPtr< Path > &path, const SharedPtr< Peer > &peer, Buf &pkt, int packetSize)
{
#if 0
	if (packetSize < (int)sizeof(Protocol::OK::Header)) {
		RR->t->incomingPacketDropped(tPtr,0x4c1f1ff7,0,0,identityFromPeerPtr(peer),path->address(),0,Protocol::VERB_OK,ZT_TRACE_PACKET_DROP_REASON_MALFORMED_PACKET);
		return false;
	}
	Protocol::Header &ph = pkt.as<Protocol::Header>();

	if (!peer->rateGateInboundWhoisRequest(RR->node->now())) {
		RR->t->incomingPacketDropped(tPtr,0x19f7194a,ph.packetId,0,peer->identity(),path->address(),Protocol::packetHops(ph),Protocol::VERB_WHOIS,ZT_TRACE_PACKET_DROP_REASON_RATE_LIMIT_EXCEEDED);
		return true;
	}

	Buf outp;
	Protocol::OK::WHOIS &outh = outp.as<Protocol::OK::WHOIS>();
	int ptr = sizeof(Protocol::Header);
	while ((ptr + ZT_ADDRESS_LENGTH) <= packetSize) {
		outh.h.h.packetId = Protocol::getPacketId();
		peer->address().copyTo(outh.h.h.destination);
		RR->identity.address().copyTo(outh.h.h.source);
		outh.h.h.flags = 0;
		outh.h.h.verb = Protocol::VERB_OK;

		outh.h.inReVerb = Protocol::VERB_WHOIS;
		outh.h.inRePacketId = ph.packetId;

		int outl = sizeof(Protocol::OK::WHOIS);
		while ( ((ptr + ZT_ADDRESS_LENGTH) <= packetSize) && ((outl + ZT_IDENTITY_MARSHAL_SIZE_MAX + ZT_LOCATOR_MARSHAL_SIZE_MAX) < ZT_PROTO_MAX_PACKET_LENGTH) ) {
			const SharedPtr<Peer> &wp(RR->topology->peer(tPtr,Address(pkt.unsafeData + ptr)));
			if (wp) {
				outp.wO(outl,wp->identity());
				if (peer->remoteVersionProtocol() >= 11) { // older versions don't know what a locator is
					const Locator loc(wp->locator());
					outp.wO(outl,loc);
				}
				if (Buf::writeOverflow(outl)) { // sanity check, shouldn't be possible
					RR->t->unexpectedError(tPtr,0xabc0f183,"Buf write overflow building OK(WHOIS) to reply to %s",Trace::str(peer->address(),path).s);
					return false;
				}
			}
			ptr += ZT_ADDRESS_LENGTH;
		}

		if (outl > (int)sizeof(Protocol::OK::WHOIS)) {
			Protocol::armor(outp,outl,peer->key(),peer->cipher());
			path->send(RR,tPtr,outp.unsafeData,outl,RR->node->now());
		}
	}

	return true;
#endif
}

bool VL1::m_RENDEZVOUS(void *tPtr, const uint64_t packetId, const unsigned int auth, const SharedPtr< Path > &path, const SharedPtr< Peer > &peer, Buf &pkt, int packetSize)
{
#if 0
	if (RR->topology->isRoot(peer->identity())) {
		if (packetSize < (int)sizeof(Protocol::RENDEZVOUS)) {
			RR->t->incomingPacketDropped(tPtr,0x43e90ab3,Protocol::packetId(pkt,packetSize),0,peer->identity(),path->address(),Protocol::packetHops(pkt,packetSize),Protocol::VERB_RENDEZVOUS,ZT_TRACE_PACKET_DROP_REASON_MALFORMED_PACKET);
			return false;
		}
		Protocol::RENDEZVOUS &rdv = pkt.as<Protocol::RENDEZVOUS>();

		const SharedPtr<Peer> with(RR->topology->peer(tPtr,Address(rdv.peerAddress)));
		if (with) {
			const int64_t now = RR->node->now();
			const unsigned int port = Utils::ntoh(rdv.port);
			if (port != 0) {
				switch(rdv.addressLength) {
					case 4:
					case 16:
						if ((int)(sizeof(Protocol::RENDEZVOUS) + rdv.addressLength) <= packetSize) {
							const InetAddress atAddr(pkt.unsafeData + sizeof(Protocol::RENDEZVOUS),rdv.addressLength,port);
							peer->tryToContactAt(tPtr,Endpoint(atAddr),now,false);
							RR->t->tryingNewPath(tPtr,0x55a19aaa,with->identity(),atAddr,path->address(),Protocol::packetId(pkt,packetSize),Protocol::VERB_RENDEZVOUS,peer->identity(),ZT_TRACE_TRYING_NEW_PATH_REASON_RENDEZVOUS);
						}
						break;
					case 255: {
						Endpoint ep;
						int p = sizeof(Protocol::RENDEZVOUS);
						int epl = pkt.rO(p,ep);
						if ((epl > 0) && (ep) && (!Buf::readOverflow(p,packetSize))) {
							switch (ep.type()) {
								case Endpoint::TYPE_INETADDR_V4:
								case Endpoint::TYPE_INETADDR_V6:
									peer->tryToContactAt(tPtr,ep,now,false);
									RR->t->tryingNewPath(tPtr,0x55a19aab,with->identity(),ep.inetAddr(),path->address(),Protocol::packetId(pkt,packetSize),Protocol::VERB_RENDEZVOUS,peer->identity(),ZT_TRACE_TRYING_NEW_PATH_REASON_RENDEZVOUS);
									break;
								default:
									break;
							}
						}
					} break;
				}
			}
		}
	}
	return true;
#endif
}

bool VL1::m_ECHO(void *tPtr, const uint64_t packetId, const unsigned int auth, const SharedPtr< Path > &path, const SharedPtr< Peer > &peer, Buf &pkt, int packetSize)
{
#if 0
	const uint64_t packetId = Protocol::packetId(pkt,packetSize);
	const uint64_t now = RR->node->now();
	if (packetSize < (int)sizeof(Protocol::Header)) {
		RR->t->incomingPacketDropped(tPtr,0x14d70bb0,packetId,0,peer->identity(),path->address(),Protocol::packetHops(pkt,packetSize),Protocol::VERB_ECHO,ZT_TRACE_PACKET_DROP_REASON_MALFORMED_PACKET);
		return false;
	}

	if (peer->rateGateEchoRequest(now)) {
		Buf outp;
		Protocol::OK::ECHO &outh = outp.as<Protocol::OK::ECHO>();
		outh.h.h.packetId = Protocol::getPacketId();
		peer->address().copyTo(outh.h.h.destination);
		RR->identity.address().copyTo(outh.h.h.source);
		outh.h.h.flags = 0;
		outh.h.h.verb = Protocol::VERB_OK;
		outh.h.inReVerb = Protocol::VERB_ECHO;
		outh.h.inRePacketId = packetId;
		int outl = sizeof(Protocol::OK::ECHO);
		outp.wB(outl,pkt.unsafeData + sizeof(Protocol::Header),packetSize - sizeof(Protocol::Header));

		if (Buf::writeOverflow(outl)) {
			RR->t->incomingPacketDropped(tPtr,0x14d70bb0,packetId,0,peer->identity(),path->address(),Protocol::packetHops(pkt,packetSize),Protocol::VERB_ECHO,ZT_TRACE_PACKET_DROP_REASON_MALFORMED_PACKET);
			return false;
		}

		Protocol::armor(outp,outl,peer->key(),peer->cipher());
		path->send(RR,tPtr,outp.unsafeData,outl,now);
	} else {
		RR->t->incomingPacketDropped(tPtr,0x27878bc1,packetId,0,peer->identity(),path->address(),Protocol::packetHops(pkt,packetSize),Protocol::VERB_ECHO,ZT_TRACE_PACKET_DROP_REASON_RATE_LIMIT_EXCEEDED);
	}

	return true;
#endif
}

bool VL1::m_PUSH_DIRECT_PATHS(void *tPtr, const uint64_t packetId, const unsigned int auth, const SharedPtr< Path > &path, const SharedPtr< Peer > &peer, Buf &pkt, int packetSize)
{
#if 0
	if (packetSize < (int)sizeof(Protocol::PUSH_DIRECT_PATHS)) {
		RR->t->incomingPacketDropped(tPtr,0x1bb1bbb1,Protocol::packetId(pkt,packetSize),0,peer->identity(),path->address(),Protocol::packetHops(pkt,packetSize),Protocol::VERB_PUSH_DIRECT_PATHS,ZT_TRACE_PACKET_DROP_REASON_MALFORMED_PACKET);
		return false;
	}
	Protocol::PUSH_DIRECT_PATHS &pdp = pkt.as<Protocol::PUSH_DIRECT_PATHS>();

	int ptr = sizeof(Protocol::PUSH_DIRECT_PATHS);
	const unsigned int numPaths = Utils::ntoh(pdp.numPaths);
	InetAddress a;
	Endpoint ep;
	for(unsigned int pi=0;pi<numPaths;++pi) {
		/*const uint8_t flags = pkt.rI8(ptr);*/ ++ptr; // flags are not presently used

		const int xas = (int)pkt.rI16(ptr);
		//const uint8_t *const extendedAttrs = pkt.rBnc(ptr,xas);
		ptr += xas;

		const unsigned int addrType = pkt.rI8(ptr);
		const unsigned int addrRecordLen = pkt.rI8(ptr);
		if (addrRecordLen == 0) {
			RR->t->incomingPacketDropped(tPtr,0xaed00118,pdp.h.packetId,0,peer->identity(),path->address(),Protocol::packetHops(pdp.h),Protocol::VERB_PUSH_DIRECT_PATHS,ZT_TRACE_PACKET_DROP_REASON_MALFORMED_PACKET);
			return false;
		}
		if (Buf::readOverflow(ptr,packetSize)) {
			RR->t->incomingPacketDropped(tPtr,0xb450e10f,pdp.h.packetId,0,peer->identity(),path->address(),Protocol::packetHops(pdp.h),Protocol::VERB_PUSH_DIRECT_PATHS,ZT_TRACE_PACKET_DROP_REASON_MALFORMED_PACKET);
			return false;
		}

		const void *addrBytes = nullptr;
		unsigned int addrLen = 0;
		unsigned int addrPort = 0;
		switch(addrType) {
			case 0:
				addrBytes = pkt.rBnc(ptr,addrRecordLen);
				addrLen = addrRecordLen;
				break;
			case 4:
				addrBytes = pkt.rBnc(ptr,4);
				addrLen = 4;
				addrPort = pkt.rI16(ptr);
				break;
			case 6:
				addrBytes = pkt.rBnc(ptr,16);
				addrLen = 16;
				addrPort = pkt.rI16(ptr);
				break;
			//case 200:
				// TODO: this would be a WebRTC SDP offer contained in the extended attrs field
				//break;
			default: break;
		}

		if (Buf::readOverflow(ptr,packetSize)) {
			RR->t->incomingPacketDropped(tPtr,0xb4d0f10f,pdp.h.packetId,0,peer->identity(),path->address(),Protocol::packetHops(pdp.h),Protocol::VERB_PUSH_DIRECT_PATHS,ZT_TRACE_PACKET_DROP_REASON_MALFORMED_PACKET);
			return false;
		}

		if (addrPort) {
			a.set(addrBytes,addrLen,addrPort);
		} else if (addrLen) {
			if (ep.unmarshal(reinterpret_cast<const uint8_t *>(addrBytes),(int)addrLen) <= 0) {
				RR->t->incomingPacketDropped(tPtr,0x00e0f00d,pdp.h.packetId,0,peer->identity(),path->address(),Protocol::packetHops(pdp.h),Protocol::VERB_PUSH_DIRECT_PATHS,ZT_TRACE_PACKET_DROP_REASON_MALFORMED_PACKET);
				return false;
			}

			switch(ep.type()) {
				case Endpoint::TYPE_INETADDR_V4:
				case Endpoint::TYPE_INETADDR_V6:
					a = ep.inetAddr();
					break;
				default: // other types are not supported yet
					break;
			}
		}

		if (a) {
			RR->t->tryingNewPath(tPtr,0xa5ab1a43,peer->identity(),a,path->address(),Protocol::packetId(pkt,packetSize),Protocol::VERB_RENDEZVOUS,peer->identity(),ZT_TRACE_TRYING_NEW_PATH_REASON_RECEIVED_PUSH_DIRECT_PATHS);
		}

		ptr += (int)addrRecordLen;
	}

	// TODO: add to a peer try-queue

	return true;
#endif
}

bool VL1::m_USER_MESSAGE(void *tPtr, const uint64_t packetId, const unsigned int auth, const SharedPtr< Path > &path, const SharedPtr< Peer > &peer, Buf &pkt, int packetSize)
{
	// TODO
	return true;
}

bool VL1::m_ENCAP(void *tPtr, const uint64_t packetId, const unsigned int auth, const SharedPtr< Path > &path, const SharedPtr< Peer > &peer, Buf &pkt, int packetSize)
{
	// TODO: not implemented yet
	return true;
}

} // namespace ZeroTier