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ZeroTierOne/node/Packet.hpp

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/*
* 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: 2026-01-01
*
* 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.
*/
/****/
#ifndef ZT_N_PACKET_HPP
#define ZT_N_PACKET_HPP
#include <stdint.h>
#include <string.h>
#include <stdio.h>
#include <string>
#include <iostream>
#include "Constants.hpp"
#include "Address.hpp"
#include "Poly1305.hpp"
#include "Salsa20.hpp"
#include "AES.hpp"
#include "Utils.hpp"
#include "Buffer.hpp"
/**
* Protocol version -- incremented only for major changes
*
* 1 - 0.2.0 ... 0.2.5
* 2 - 0.3.0 ... 0.4.5
* + Added signature and originating peer to multicast frame
* + Double size of multicast frame bloom filter
* 3 - 0.5.0 ... 0.6.0
* + Yet another multicast redesign
* + New crypto completely changes key agreement cipher
* 4 - 0.6.0 ... 1.0.6
* + BREAKING CHANGE: New identity format based on hashcash design
* 5 - 1.1.0 ... 1.1.5
* + Supports echo
* + Supports in-band world (root server definition) updates
* + Clustering! (Though this will work with protocol v4 clients.)
* + Otherwise backward compatible with protocol v4
* 6 - 1.1.5 ... 1.1.10
* + Network configuration format revisions including binary values
* 7 - 1.1.10 ... 1.1.17
* + Introduce trusted paths for local SDN use
* 8 - 1.1.17 ... 1.2.0
* + Multipart network configurations for large network configs
* + Tags and Capabilities
* + Inline push of CertificateOfMembership deprecated
* 9 - 1.2.0 ... 1.2.14
* 10 - 1.4.0 ... 1.4.6
* 11 - 1.4.7 ... 1.4.8
* + Multipath capability and load balancing (beta)
* 12 - 1.4.8 ... CURRENT (1.4 series)
* + AES-GMAC-SIV backported for faster peer-to-peer crypto
*/
#define ZT_PROTO_VERSION 12
/**
* Minimum supported protocol version
*/
#define ZT_PROTO_VERSION_MIN 4
/**
* Maximum hop count allowed by packet structure (3 bits, 0-7)
*
* This is a protocol constant. It's the maximum allowed by the length
* of the hop counter -- three bits. See node/Constants.hpp for the
* pragmatic forwarding limit, which is typically lower.
*/
#define ZT_PROTO_MAX_HOPS 7
/**
* Cipher suite: Curve25519/Poly1305/Salsa20/12/NOCRYPT
*
* This specifies Poly1305 MAC using a 32-bit key derived from the first
* 32 bytes of a Salsa20/12 keystream as in the Salsa20/12 cipher suite,
* but the payload is not encrypted. This is currently only used to send
* HELLO since that's the public key specification packet and must be
* sent in the clear. Key agreement is performed using Curve25519 elliptic
* curve Diffie-Hellman.
*/
#define ZT_PROTO_CIPHER_SUITE__C25519_POLY1305_NONE 0
/**
* Cipher suite: Curve25519/Poly1305/Salsa20/12
*
* This specifies Poly1305 using the first 32 bytes of a Salsa20/12 key
* stream as its one-time-use key followed by payload encryption with
* the remaining Salsa20/12 key stream. Key agreement is performed using
* Curve25519 elliptic curve Diffie-Hellman.
*/
#define ZT_PROTO_CIPHER_SUITE__C25519_POLY1305_SALSA2012 1
/**
* AES-GMAC-SIV backported from 2.x
*/
#define ZT_PROTO_CIPHER_SUITE__AES_GMAC_SIV 3
/**
* AES-GMAC-SIV first of two keys
*/
#define ZT_KBKDF_LABEL_AES_GMAC_SIV_K0 '0'
/**
* AES-GMAC-SIV second of two keys
*/
#define ZT_KBKDF_LABEL_AES_GMAC_SIV_K1 '1'
/**
* Cipher suite: NONE
*
* This differs from POLY1305/NONE in that *no* crypto is done, not even
* authentication. This is for trusted local LAN interconnects for internal
* SDN use within a data center.
*
* For this mode the MAC field becomes a trusted path ID and must match the
* configured ID of a trusted path or the packet is discarded.
*/
#define ZT_PROTO_CIPHER_SUITE__NO_CRYPTO_TRUSTED_PATH 2
/**
* DEPRECATED payload encrypted flag, may be re-used in the future.
*
* This has been replaced by the three-bit cipher suite selection field.
*/
#define ZT_PROTO_FLAG_ENCRYPTED 0x80
/**
* Header flag indicating that a packet is fragmented
*
* If this flag is set, the receiver knows to expect more than one fragment.
* See Packet::Fragment for details.
*/
#define ZT_PROTO_FLAG_FRAGMENTED 0x40
/**
* Verb flag indicating payload is compressed with LZ4
*/
#define ZT_PROTO_VERB_FLAG_COMPRESSED 0x80
/**
* Rounds used for Salsa20 encryption in ZT
*
* Discussion:
*
* DJB (Salsa20's designer) designed Salsa20 with a significant margin of 20
* rounds, but has said repeatedly that 12 is likely sufficient. So far (as of
* July 2015) there are no published attacks against 12 rounds, let alone 20.
*
* In cryptography, a "break" means something different from what it means in
* common discussion. If a cipher is 256 bits strong and someone finds a way
* to reduce key search to 254 bits, this constitutes a "break" in the academic
* literature. 254 bits is still far beyond what can be leveraged to accomplish
* a "break" as most people would understand it -- the actual decryption and
* reading of traffic.
*
* Nevertheless, "attacks only get better" as cryptographers like to say. As
* a result, they recommend not using anything that's shown any weakness even
* if that weakness is so far only meaningful to academics. It may be a sign
* of a deeper problem.
*
* So why choose a lower round count?
*
* Turns out the speed difference is nontrivial. On a Macbook Pro (Core i3) 20
* rounds of SSE-optimized Salsa20 achieves ~508mb/sec/core, while 12 rounds
* hits ~832mb/sec/core. ZeroTier is designed for multiple objectives:
* security, simplicity, and performance. In this case a deference was made
* for performance.
*
* Meta discussion:
*
* The cipher is not the thing you should be paranoid about.
*
* I'll qualify that. If the cipher is known to be weak, like RC4, or has a
* key size that is too small, like DES, then yes you should worry about
* the cipher.
*
* But if the cipher is strong and your adversary is anyone other than the
* intelligence apparatus of a major superpower, you are fine in that
* department.
*
* Go ahead. Search for the last ten vulnerabilities discovered in SSL. Not
* a single one involved the breaking of a cipher. Now broaden your search.
* Look for issues with SSH, IPSec, etc. The only cipher-related issues you
* will find might involve the use of RC4 or MD5, algorithms with known
* issues or small key/digest sizes. But even weak ciphers are difficult to
* exploit in the real world -- you usually need a lot of data and a lot of
* compute time. No, virtually EVERY security vulnerability you will find
* involves a problem with the IMPLEMENTATION not with the cipher.
*
* A flaw in ZeroTier's protocol or code is incredibly, unbelievably
* more likely than a flaw in Salsa20 or any other cipher or cryptographic
* primitive it uses. We're talking odds of dying in a car wreck vs. odds of
* being personally impacted on the head by a meteorite. Nobody without a
* billion dollar budget is going to break into your network by actually
* cracking Salsa20/12 (or even /8) in the field.
*
* So stop worrying about the cipher unless you are, say, the Kremlin and your
* adversary is the NSA and the GCHQ. In that case... well that's above my
* pay grade. I'll just say defense in depth.
*/
#define ZT_PROTO_SALSA20_ROUNDS 12
/**
* PUSH_DIRECT_PATHS flag: forget path
*/
#define ZT_PUSH_DIRECT_PATHS_FLAG_FORGET_PATH 0x01
/**
* PUSH_DIRECT_PATHS flag: cluster redirect
*/
#define ZT_PUSH_DIRECT_PATHS_FLAG_CLUSTER_REDIRECT 0x02
// Field indexes in packet header
#define ZT_PACKET_IDX_IV 0
#define ZT_PACKET_IDX_DEST 8
#define ZT_PACKET_IDX_SOURCE 13
#define ZT_PACKET_IDX_FLAGS 18
#define ZT_PACKET_IDX_MAC 19
#define ZT_PACKET_IDX_VERB 27
#define ZT_PACKET_IDX_PAYLOAD 28
/**
* Packet buffer size (can be changed)
*/
#define ZT_PROTO_MAX_PACKET_LENGTH (ZT_MAX_PACKET_FRAGMENTS * ZT_DEFAULT_PHYSMTU)
/**
* Minimum viable packet length (a.k.a. header length)
*/
#define ZT_PROTO_MIN_PACKET_LENGTH ZT_PACKET_IDX_PAYLOAD
// Indexes of fields in fragment header
#define ZT_PACKET_FRAGMENT_IDX_PACKET_ID 0
#define ZT_PACKET_FRAGMENT_IDX_DEST 8
#define ZT_PACKET_FRAGMENT_IDX_FRAGMENT_INDICATOR 13
#define ZT_PACKET_FRAGMENT_IDX_FRAGMENT_NO 14
#define ZT_PACKET_FRAGMENT_IDX_HOPS 15
#define ZT_PACKET_FRAGMENT_IDX_PAYLOAD 16
/**
* Magic number found at ZT_PACKET_FRAGMENT_IDX_FRAGMENT_INDICATOR
*/
#define ZT_PACKET_FRAGMENT_INDICATOR ZT_ADDRESS_RESERVED_PREFIX
/**
* Minimum viable fragment length
*/
#define ZT_PROTO_MIN_FRAGMENT_LENGTH ZT_PACKET_FRAGMENT_IDX_PAYLOAD
// Field indices for parsing verbs -------------------------------------------
// Some verbs have variable-length fields. Those aren't fully defined here
// yet-- instead they are parsed using relative indexes in IncomingPacket.
// See their respective handler functions.
#define ZT_PROTO_VERB_HELLO_IDX_PROTOCOL_VERSION (ZT_PACKET_IDX_PAYLOAD)
#define ZT_PROTO_VERB_HELLO_IDX_MAJOR_VERSION (ZT_PROTO_VERB_HELLO_IDX_PROTOCOL_VERSION + 1)
#define ZT_PROTO_VERB_HELLO_IDX_MINOR_VERSION (ZT_PROTO_VERB_HELLO_IDX_MAJOR_VERSION + 1)
#define ZT_PROTO_VERB_HELLO_IDX_REVISION (ZT_PROTO_VERB_HELLO_IDX_MINOR_VERSION + 1)
#define ZT_PROTO_VERB_HELLO_IDX_TIMESTAMP (ZT_PROTO_VERB_HELLO_IDX_REVISION + 2)
#define ZT_PROTO_VERB_HELLO_IDX_IDENTITY (ZT_PROTO_VERB_HELLO_IDX_TIMESTAMP + 8)
#define ZT_PROTO_VERB_ERROR_IDX_IN_RE_VERB (ZT_PACKET_IDX_PAYLOAD)
#define ZT_PROTO_VERB_ERROR_IDX_IN_RE_PACKET_ID (ZT_PROTO_VERB_ERROR_IDX_IN_RE_VERB + 1)
#define ZT_PROTO_VERB_ERROR_IDX_ERROR_CODE (ZT_PROTO_VERB_ERROR_IDX_IN_RE_PACKET_ID + 8)
#define ZT_PROTO_VERB_ERROR_IDX_PAYLOAD (ZT_PROTO_VERB_ERROR_IDX_ERROR_CODE + 1)
#define ZT_PROTO_VERB_OK_IDX_IN_RE_VERB (ZT_PACKET_IDX_PAYLOAD)
#define ZT_PROTO_VERB_OK_IDX_IN_RE_PACKET_ID (ZT_PROTO_VERB_OK_IDX_IN_RE_VERB + 1)
#define ZT_PROTO_VERB_OK_IDX_PAYLOAD (ZT_PROTO_VERB_OK_IDX_IN_RE_PACKET_ID + 8)
#define ZT_PROTO_VERB_WHOIS_IDX_ZTADDRESS (ZT_PACKET_IDX_PAYLOAD)
#define ZT_PROTO_VERB_RENDEZVOUS_IDX_FLAGS (ZT_PACKET_IDX_PAYLOAD)
#define ZT_PROTO_VERB_RENDEZVOUS_IDX_ZTADDRESS (ZT_PROTO_VERB_RENDEZVOUS_IDX_FLAGS + 1)
#define ZT_PROTO_VERB_RENDEZVOUS_IDX_PORT (ZT_PROTO_VERB_RENDEZVOUS_IDX_ZTADDRESS + 5)
#define ZT_PROTO_VERB_RENDEZVOUS_IDX_ADDRLEN (ZT_PROTO_VERB_RENDEZVOUS_IDX_PORT + 2)
#define ZT_PROTO_VERB_RENDEZVOUS_IDX_ADDRESS (ZT_PROTO_VERB_RENDEZVOUS_IDX_ADDRLEN + 1)
#define ZT_PROTO_VERB_FRAME_IDX_NETWORK_ID (ZT_PACKET_IDX_PAYLOAD)
#define ZT_PROTO_VERB_FRAME_IDX_ETHERTYPE (ZT_PROTO_VERB_FRAME_IDX_NETWORK_ID + 8)
#define ZT_PROTO_VERB_FRAME_IDX_PAYLOAD (ZT_PROTO_VERB_FRAME_IDX_ETHERTYPE + 2)
#define ZT_PROTO_VERB_EXT_FRAME_IDX_NETWORK_ID (ZT_PACKET_IDX_PAYLOAD)
#define ZT_PROTO_VERB_EXT_FRAME_LEN_NETWORK_ID 8
#define ZT_PROTO_VERB_EXT_FRAME_IDX_FLAGS (ZT_PROTO_VERB_EXT_FRAME_IDX_NETWORK_ID + ZT_PROTO_VERB_EXT_FRAME_LEN_NETWORK_ID)
#define ZT_PROTO_VERB_EXT_FRAME_LEN_FLAGS 1
#define ZT_PROTO_VERB_EXT_FRAME_IDX_COM (ZT_PROTO_VERB_EXT_FRAME_IDX_FLAGS + ZT_PROTO_VERB_EXT_FRAME_LEN_FLAGS)
#define ZT_PROTO_VERB_EXT_FRAME_IDX_TO (ZT_PROTO_VERB_EXT_FRAME_IDX_FLAGS + ZT_PROTO_VERB_EXT_FRAME_LEN_FLAGS)
#define ZT_PROTO_VERB_EXT_FRAME_LEN_TO 6
#define ZT_PROTO_VERB_EXT_FRAME_IDX_FROM (ZT_PROTO_VERB_EXT_FRAME_IDX_TO + ZT_PROTO_VERB_EXT_FRAME_LEN_TO)
#define ZT_PROTO_VERB_EXT_FRAME_LEN_FROM 6
#define ZT_PROTO_VERB_EXT_FRAME_IDX_ETHERTYPE (ZT_PROTO_VERB_EXT_FRAME_IDX_FROM + ZT_PROTO_VERB_EXT_FRAME_LEN_FROM)
#define ZT_PROTO_VERB_EXT_FRAME_LEN_ETHERTYPE 2
#define ZT_PROTO_VERB_EXT_FRAME_IDX_PAYLOAD (ZT_PROTO_VERB_EXT_FRAME_IDX_ETHERTYPE + ZT_PROTO_VERB_EXT_FRAME_LEN_ETHERTYPE)
#define ZT_PROTO_VERB_NETWORK_CONFIG_REQUEST_IDX_NETWORK_ID (ZT_PACKET_IDX_PAYLOAD)
#define ZT_PROTO_VERB_NETWORK_CONFIG_REQUEST_IDX_DICT_LEN (ZT_PROTO_VERB_NETWORK_CONFIG_REQUEST_IDX_NETWORK_ID + 8)
#define ZT_PROTO_VERB_NETWORK_CONFIG_REQUEST_IDX_DICT (ZT_PROTO_VERB_NETWORK_CONFIG_REQUEST_IDX_DICT_LEN + 2)
#define ZT_PROTO_VERB_MULTICAST_GATHER_IDX_NETWORK_ID (ZT_PACKET_IDX_PAYLOAD)
#define ZT_PROTO_VERB_MULTICAST_GATHER_IDX_FLAGS (ZT_PROTO_VERB_MULTICAST_GATHER_IDX_NETWORK_ID + 8)
#define ZT_PROTO_VERB_MULTICAST_GATHER_IDX_MAC (ZT_PROTO_VERB_MULTICAST_GATHER_IDX_FLAGS + 1)
#define ZT_PROTO_VERB_MULTICAST_GATHER_IDX_ADI (ZT_PROTO_VERB_MULTICAST_GATHER_IDX_MAC + 6)
#define ZT_PROTO_VERB_MULTICAST_GATHER_IDX_GATHER_LIMIT (ZT_PROTO_VERB_MULTICAST_GATHER_IDX_ADI + 4)
#define ZT_PROTO_VERB_MULTICAST_GATHER_IDX_COM (ZT_PROTO_VERB_MULTICAST_GATHER_IDX_GATHER_LIMIT + 4)
// Note: COM, GATHER_LIMIT, and SOURCE_MAC are optional, and so are specified without size
#define ZT_PROTO_VERB_MULTICAST_FRAME_IDX_NETWORK_ID (ZT_PACKET_IDX_PAYLOAD)
#define ZT_PROTO_VERB_MULTICAST_FRAME_IDX_FLAGS (ZT_PROTO_VERB_MULTICAST_FRAME_IDX_NETWORK_ID + 8)
#define ZT_PROTO_VERB_MULTICAST_FRAME_IDX_COM (ZT_PROTO_VERB_MULTICAST_FRAME_IDX_FLAGS + 1)
#define ZT_PROTO_VERB_MULTICAST_FRAME_IDX_GATHER_LIMIT (ZT_PROTO_VERB_MULTICAST_FRAME_IDX_FLAGS + 1)
#define ZT_PROTO_VERB_MULTICAST_FRAME_IDX_SOURCE_MAC (ZT_PROTO_VERB_MULTICAST_FRAME_IDX_FLAGS + 1)
#define ZT_PROTO_VERB_MULTICAST_FRAME_IDX_DEST_MAC (ZT_PROTO_VERB_MULTICAST_FRAME_IDX_FLAGS + 1)
#define ZT_PROTO_VERB_MULTICAST_FRAME_IDX_DEST_ADI (ZT_PROTO_VERB_MULTICAST_FRAME_IDX_DEST_MAC + 6)
#define ZT_PROTO_VERB_MULTICAST_FRAME_IDX_ETHERTYPE (ZT_PROTO_VERB_MULTICAST_FRAME_IDX_DEST_ADI + 4)
#define ZT_PROTO_VERB_MULTICAST_FRAME_IDX_FRAME (ZT_PROTO_VERB_MULTICAST_FRAME_IDX_ETHERTYPE + 2)
#define ZT_PROTO_VERB_HELLO__OK__IDX_TIMESTAMP (ZT_PROTO_VERB_OK_IDX_PAYLOAD)
#define ZT_PROTO_VERB_HELLO__OK__IDX_PROTOCOL_VERSION (ZT_PROTO_VERB_HELLO__OK__IDX_TIMESTAMP + 8)
#define ZT_PROTO_VERB_HELLO__OK__IDX_MAJOR_VERSION (ZT_PROTO_VERB_HELLO__OK__IDX_PROTOCOL_VERSION + 1)
#define ZT_PROTO_VERB_HELLO__OK__IDX_MINOR_VERSION (ZT_PROTO_VERB_HELLO__OK__IDX_MAJOR_VERSION + 1)
#define ZT_PROTO_VERB_HELLO__OK__IDX_REVISION (ZT_PROTO_VERB_HELLO__OK__IDX_MINOR_VERSION + 1)
#define ZT_PROTO_VERB_WHOIS__OK__IDX_IDENTITY (ZT_PROTO_VERB_OK_IDX_PAYLOAD)
#define ZT_PROTO_VERB_NETWORK_CONFIG_REQUEST__OK__IDX_NETWORK_ID (ZT_PROTO_VERB_OK_IDX_PAYLOAD)
#define ZT_PROTO_VERB_NETWORK_CONFIG_REQUEST__OK__IDX_DICT_LEN (ZT_PROTO_VERB_NETWORK_CONFIG_REQUEST__OK__IDX_NETWORK_ID + 8)
#define ZT_PROTO_VERB_NETWORK_CONFIG_REQUEST__OK__IDX_DICT (ZT_PROTO_VERB_NETWORK_CONFIG_REQUEST__OK__IDX_DICT_LEN + 2)
#define ZT_PROTO_VERB_MULTICAST_GATHER__OK__IDX_NETWORK_ID (ZT_PROTO_VERB_OK_IDX_PAYLOAD)
#define ZT_PROTO_VERB_MULTICAST_GATHER__OK__IDX_MAC (ZT_PROTO_VERB_MULTICAST_GATHER__OK__IDX_NETWORK_ID + 8)
#define ZT_PROTO_VERB_MULTICAST_GATHER__OK__IDX_ADI (ZT_PROTO_VERB_MULTICAST_GATHER__OK__IDX_MAC + 6)
#define ZT_PROTO_VERB_MULTICAST_GATHER__OK__IDX_GATHER_RESULTS (ZT_PROTO_VERB_MULTICAST_GATHER__OK__IDX_ADI + 4)
#define ZT_PROTO_VERB_MULTICAST_FRAME__OK__IDX_NETWORK_ID (ZT_PROTO_VERB_OK_IDX_PAYLOAD)
#define ZT_PROTO_VERB_MULTICAST_FRAME__OK__IDX_MAC (ZT_PROTO_VERB_MULTICAST_FRAME__OK__IDX_NETWORK_ID + 8)
#define ZT_PROTO_VERB_MULTICAST_FRAME__OK__IDX_ADI (ZT_PROTO_VERB_MULTICAST_FRAME__OK__IDX_MAC + 6)
#define ZT_PROTO_VERB_MULTICAST_FRAME__OK__IDX_FLAGS (ZT_PROTO_VERB_MULTICAST_FRAME__OK__IDX_ADI + 4)
#define ZT_PROTO_VERB_MULTICAST_FRAME__OK__IDX_COM_AND_GATHER_RESULTS (ZT_PROTO_VERB_MULTICAST_FRAME__OK__IDX_FLAGS + 1)
// ---------------------------------------------------------------------------
namespace ZeroTier {
/**
* ZeroTier packet
*
* Packet format:
* <[8] 64-bit packet ID / crypto IV / packet counter>
* <[5] destination ZT address>
* <[5] source ZT address>
* <[1] flags/cipher/hops>
* <[8] 64-bit MAC (or trusted path ID in trusted path mode)>
* [... -- begin encryption envelope -- ...]
* <[1] encrypted flags (MS 3 bits) and verb (LS 5 bits)>
* [... verb-specific payload ...]
*
* Packets smaller than 28 bytes are invalid and silently discarded.
*
* The 64-bit packet ID is a strongly random value used as a crypto IV.
* Its least significant 3 bits are also used as a monotonically increasing
* (and looping) counter for sending packets to a particular recipient. This
* can be used for link quality monitoring and reporting and has no crypto
* impact as it does not increase the likelihood of an IV collision. (The
* crypto we use is not sensitive to the nature of the IV, only that it does
* not repeat.)
*
* The flags/cipher/hops bit field is: FFCCCHHH where C is a 3-bit cipher
* selection allowing up to 7 cipher suites, F is outside-envelope flags,
* and H is hop count.
*
* The three-bit hop count is the only part of a packet that is mutable in
* transit without invalidating the MAC. All other bits in the packet are
* immutable. This is because intermediate nodes can increment the hop
* count up to 7 (protocol max).
*
* For unencrypted packets, MAC is computed on plaintext. Only HELLO is ever
* sent in the clear, as it's the "here is my public key" message.
*/
class Packet : public Buffer<ZT_PROTO_MAX_PACKET_LENGTH>
{
public:
/**
* A packet fragment
*
* Fragments are sent if a packet is larger than UDP MTU. The first fragment
* is sent with its normal header with the fragmented flag set. Remaining
* fragments are sent this way.
*
* The fragmented bit indicates that there is at least one fragment. Fragments
* themselves contain the total, so the receiver must "learn" this from the
* first fragment it receives.
*
* Fragments are sent with the following format:
* <[8] packet ID of packet whose fragment this belongs to>
* <[5] destination ZT address>
* <[1] 0xff, a reserved address, signals that this isn't a normal packet>
* <[1] total fragments (most significant 4 bits), fragment no (LS 4 bits)>
* <[1] ZT hop count (top 5 bits unused and must be zero)>
* <[...] fragment data>
*
* The protocol supports a maximum of 16 fragments. If a fragment is received
* before its main packet header, it should be cached for a brief period of
* time to see if its parent arrives. Loss of any fragment constitutes packet
* loss; there is no retransmission mechanism. The receiver must wait for full
* receipt to authenticate and decrypt; there is no per-fragment MAC. (But if
* fragments are corrupt, the MAC will fail for the whole assembled packet.)
*/
class Fragment : public Buffer<ZT_PROTO_MAX_PACKET_LENGTH>
{
public:
Fragment() :
Buffer<ZT_PROTO_MAX_PACKET_LENGTH>()
{
}
template<unsigned int C2>
Fragment(const Buffer<C2> &b) :
Buffer<ZT_PROTO_MAX_PACKET_LENGTH>(b)
{
}
Fragment(const void *data,unsigned int len) :
Buffer<ZT_PROTO_MAX_PACKET_LENGTH>(data,len)
{
}
/**
* Initialize from a packet
*
* @param p Original assembled packet
* @param fragStart Start of fragment (raw index in packet data)
* @param fragLen Length of fragment in bytes
* @param fragNo Which fragment (>= 1, since 0 is Packet with end chopped off)
* @param fragTotal Total number of fragments (including 0)
*/
Fragment(const Packet &p,unsigned int fragStart,unsigned int fragLen,unsigned int fragNo,unsigned int fragTotal)
{
init(p,fragStart,fragLen,fragNo,fragTotal);
}
/**
* Initialize from a packet
*
* @param p Original assembled packet
* @param fragStart Start of fragment (raw index in packet data)
* @param fragLen Length of fragment in bytes
* @param fragNo Which fragment (>= 1, since 0 is Packet with end chopped off)
* @param fragTotal Total number of fragments (including 0)
*/
inline void init(const Packet &p,unsigned int fragStart,unsigned int fragLen,unsigned int fragNo,unsigned int fragTotal)
{
if ((fragStart + fragLen) > p.size()) {
throw ZT_EXCEPTION_OUT_OF_BOUNDS;
}
setSize(fragLen + ZT_PROTO_MIN_FRAGMENT_LENGTH);
// NOTE: this copies both the IV/packet ID and the destination address.
memcpy(field(ZT_PACKET_FRAGMENT_IDX_PACKET_ID,13),p.field(ZT_PACKET_IDX_IV,13),13);
(*this)[ZT_PACKET_FRAGMENT_IDX_FRAGMENT_INDICATOR] = ZT_PACKET_FRAGMENT_INDICATOR;
(*this)[ZT_PACKET_FRAGMENT_IDX_FRAGMENT_NO] = (char)(((fragTotal & 0xf) << 4) | (fragNo & 0xf));
(*this)[ZT_PACKET_FRAGMENT_IDX_HOPS] = 0;
memcpy(field(ZT_PACKET_FRAGMENT_IDX_PAYLOAD,fragLen),p.field(fragStart,fragLen),fragLen);
}
/**
* Get this fragment's destination
*
* @return Destination ZT address
*/
inline Address destination() const { return Address(field(ZT_PACKET_FRAGMENT_IDX_DEST,ZT_ADDRESS_LENGTH),ZT_ADDRESS_LENGTH); }
/**
* @return True if fragment is of a valid length
*/
inline bool lengthValid() const { return (size() >= ZT_PACKET_FRAGMENT_IDX_PAYLOAD); }
/**
* @return ID of packet this is a fragment of
*/
inline uint64_t packetId() const { return at<uint64_t>(ZT_PACKET_FRAGMENT_IDX_PACKET_ID); }
/**
* @return Total number of fragments in packet
*/
inline unsigned int totalFragments() const { return (((unsigned int)((*this)[ZT_PACKET_FRAGMENT_IDX_FRAGMENT_NO]) >> 4) & 0xf); }
/**
* @return Fragment number of this fragment
*/
inline unsigned int fragmentNumber() const { return ((unsigned int)((*this)[ZT_PACKET_FRAGMENT_IDX_FRAGMENT_NO]) & 0xf); }
/**
* @return Fragment ZT hop count
*/
inline unsigned int hops() const { return (unsigned int)((*this)[ZT_PACKET_FRAGMENT_IDX_HOPS]); }
/**
* Increment this packet's hop count
*/
inline void incrementHops()
{
(*this)[ZT_PACKET_FRAGMENT_IDX_HOPS] = (((*this)[ZT_PACKET_FRAGMENT_IDX_HOPS]) + 1) & ZT_PROTO_MAX_HOPS;
}
/**
* @return Length of payload in bytes
*/
inline unsigned int payloadLength() const { return ((size() > ZT_PACKET_FRAGMENT_IDX_PAYLOAD) ? (size() - ZT_PACKET_FRAGMENT_IDX_PAYLOAD) : 0); }
/**
* @return Raw packet payload
*/
inline const unsigned char *payload() const
{
return field(ZT_PACKET_FRAGMENT_IDX_PAYLOAD,size() - ZT_PACKET_FRAGMENT_IDX_PAYLOAD);
}
};
/**
* ZeroTier protocol verbs
*/
enum Verb /* Max value: 32 (5 bits) */
{
/**
* No operation (ignored, no reply)
*/
VERB_NOP = 0x00,
/**
* Announcement of a node's existence and vitals:
* <[1] protocol version>
* <[1] software major version>
* <[1] software minor version>
* <[2] software revision>
* <[8] timestamp for determining latency>
* <[...] binary serialized identity (see Identity)>
* <[...] physical destination address of packet>
* <[8] 64-bit world ID of current planet>
* <[8] 64-bit timestamp of current planet>
* [... remainder if packet is encrypted using cryptField() ...]
* <[2] 16-bit number of moons>
* [<[1] 8-bit type ID of moon>]
* [<[8] 64-bit world ID of moon>]
* [<[8] 64-bit timestamp of moon>]
* [... additional moon type/ID/timestamp tuples ...]
*
* HELLO is sent in the clear as it is how peers share their identity
* public keys. A few additional fields are sent in the clear too, but
* these are things that are public info or are easy to determine. As
* of 1.2.0 we have added a few more fields, but since these could have
* the potential to be sensitive we introduced the encryption of the
* remainder of the packet. See cryptField(). Packet MAC is still
* performed of course, so authentication occurs as normal.
*
* Destination address is the actual wire address to which the packet
* was sent. See InetAddress::serialize() for format.
*
* OK payload:
* <[8] HELLO timestamp field echo>
* <[1] protocol version>
* <[1] software major version>
* <[1] software minor version>
* <[2] software revision>
* <[...] physical destination address of packet>
* <[2] 16-bit length of world update(s) or 0 if none>
* [[...] updates to planets and/or moons]
*
* With the exception of the timestamp, the other fields pertain to the
* respondent who is sending OK and are not echoes.
*
* Note that OK is fully encrypted so no selective cryptField() of
* potentially sensitive fields is needed.
*
* ERROR has no payload.
*/
VERB_HELLO = 0x01,
/**
* Error response:
* <[1] in-re verb>
* <[8] in-re packet ID>
* <[1] error code>
* <[...] error-dependent payload>
*/
VERB_ERROR = 0x02,
/**
* Success response:
* <[1] in-re verb>
* <[8] in-re packet ID>
* <[...] request-specific payload>
*/
VERB_OK = 0x03,
/**
* Query an identity by address:
* <[5] address to look up>
* [<[...] additional addresses to look up>
*
* OK response payload:
* <[...] binary serialized identity>
* [<[...] additional binary serialized identities>]
*
* If querying a cluster, duplicate OK responses may occasionally occur.
* These must be tolerated, which is easy since they'll have info you
* already have.
*
* If the address is not found, no response is generated. The semantics
* of WHOIS is similar to ARP and NDP in that persistent retrying can
* be performed.
*/
VERB_WHOIS = 0x04,
/**
* Relay-mediated NAT traversal or firewall punching initiation:
* <[1] flags (unused, currently 0)>
* <[5] ZeroTier address of peer that might be found at this address>
* <[2] 16-bit protocol address port>
* <[1] protocol address length (4 for IPv4, 16 for IPv6)>
* <[...] protocol address (network byte order)>
*
* An upstream node can send this to inform both sides of a relay of
* information they might use to establish a direct connection.
*
* Upon receipt a peer sends HELLO to establish a direct link.
*
* No OK or ERROR is generated.
*/
VERB_RENDEZVOUS = 0x05,
/**
* ZT-to-ZT unicast ethernet frame (shortened EXT_FRAME):
* <[8] 64-bit network ID>
* <[2] 16-bit ethertype>
* <[...] ethernet payload>
*
* MAC addresses are derived from the packet's source and destination
* ZeroTier addresses. This is a shortened EXT_FRAME that elides full
* Ethernet framing and other optional flags and features when they
* are not necessary.
*
* ERROR may be generated if a membership certificate is needed for a
* closed network. Payload will be network ID.
*/
VERB_FRAME = 0x06,
/**
* Full Ethernet frame with MAC addressing and optional fields:
* <[8] 64-bit network ID>
* <[1] flags>
* <[6] destination MAC or all zero for destination node>
* <[6] source MAC or all zero for node of origin>
* <[2] 16-bit ethertype>
* <[...] ethernet payload>
*
* Flags:
* 0x01 - Certificate of network membership attached (DEPRECATED)
* 0x02 - Most significant bit of subtype (see below)
* 0x04 - Middle bit of subtype (see below)
* 0x08 - Least significant bit of subtype (see below)
* 0x10 - ACK requested in the form of OK(EXT_FRAME)
*
* Subtypes (0..7):
* 0x0 - Normal frame (bridging can be determined by checking MAC)
* 0x1 - TEEd outbound frame
* 0x2 - REDIRECTed outbound frame
* 0x3 - WATCHed outbound frame (TEE with ACK, ACK bit also set)
* 0x4 - TEEd inbound frame
* 0x5 - REDIRECTed inbound frame
* 0x6 - WATCHed inbound frame
* 0x7 - (reserved for future use)
*
* An extended frame carries full MAC addressing, making it a
* superset of VERB_FRAME. It is used for bridged traffic,
* redirected or observed traffic via rules, and can in theory
* be used for multicast though MULTICAST_FRAME exists for that
* purpose and has additional options and capabilities.
*
* OK payload (if ACK flag is set):
* <[8] 64-bit network ID>
*/
VERB_EXT_FRAME = 0x07,
/**
* ECHO request (a.k.a. ping):
* <[...] arbitrary payload>
*
* This generates OK with a copy of the transmitted payload. No ERROR
* is generated. Response to ECHO requests is optional and ECHO may be
* ignored if a node detects a possible flood.
*/
VERB_ECHO = 0x08,
/**
* Announce interest in multicast group(s):
* <[8] 64-bit network ID>
* <[6] multicast Ethernet address>
* <[4] multicast additional distinguishing information (ADI)>
* [... additional tuples of network/address/adi ...]
*
* LIKEs may be sent to any peer, though a good implementation should
* restrict them to peers on the same network they're for and to network
* controllers and root servers. In the current network, root servers
* will provide the service of final multicast cache.
*
* VERB_NETWORK_CREDENTIALS should be pushed along with this, especially
* if using upstream (e.g. root) nodes as multicast databases. This allows
* GATHERs to be authenticated.
*
* OK/ERROR are not generated.
*/
VERB_MULTICAST_LIKE = 0x09,
/**
* Network credentials push:
* [<[...] one or more certificates of membership>]
* <[1] 0x00, null byte marking end of COM array>
* <[2] 16-bit number of capabilities>
* <[...] one or more serialized Capability>
* <[2] 16-bit number of tags>
* <[...] one or more serialized Tags>
* <[2] 16-bit number of revocations>
* <[...] one or more serialized Revocations>
* <[2] 16-bit number of certificates of ownership>
* <[...] one or more serialized CertificateOfOwnership>
*
* This can be sent by anyone at any time to push network credentials.
* These will of course only be accepted if they are properly signed.
* Credentials can be for any number of networks.
*
* The use of a zero byte to terminate the COM section is for legacy
* backward compatibility. Newer fields are prefixed with a length.
*
* OK/ERROR are not generated.
*/
VERB_NETWORK_CREDENTIALS = 0x0a,
/**
* Network configuration request:
* <[8] 64-bit network ID>
* <[2] 16-bit length of request meta-data dictionary>
* <[...] string-serialized request meta-data>
* <[8] 64-bit revision of netconf we currently have>
* <[8] 64-bit timestamp of netconf we currently have>
*
* This message requests network configuration from a node capable of
* providing it.
*
* Responses to this are always whole configs intended for the recipient.
* For patches and other updates a NETWORK_CONFIG is sent instead.
*
* It would be valid and correct as of 1.2.0 to use NETWORK_CONFIG always,
* but OK(NETWORK_CONFIG_REQUEST) should be sent for compatibility.
*
* OK response payload:
* <[8] 64-bit network ID>
* <[2] 16-bit length of network configuration dictionary chunk>
* <[...] network configuration dictionary (may be incomplete)>
* [ ... end of legacy single chunk response ... ]
* <[1] 8-bit flags>
* <[8] 64-bit config update ID (should never be 0)>
* <[4] 32-bit total length of assembled dictionary>
* <[4] 32-bit index of chunk>
* [ ... end signed portion ... ]
* <[1] 8-bit chunk signature type>
* <[2] 16-bit length of chunk signature>
* <[...] chunk signature>
*
* The chunk signature signs the entire payload of the OK response.
* Currently only one signature type is supported: ed25519 (1).
*
* Each config chunk is signed to prevent memory exhaustion or
* traffic crowding DOS attacks against config fragment assembly.
*
* If the packet is from the network controller it is permitted to end
* before the config update ID or other chunking related or signature
* fields. This is to support older controllers that don't include
* these fields and may be removed in the future.
*
* ERROR response payload:
* <[8] 64-bit network ID>
* <[2] 16-bit length of error-related data (optional)>
* <[...] error-related data (optional)>
*
* Error related data is a Dictionary containing things like a URL
* for authentication or a human-readable error message, and is
* optional and may be absent or empty.
*/
VERB_NETWORK_CONFIG_REQUEST = 0x0b,
/**
* Network configuration data push:
* <[8] 64-bit network ID>
* <[2] 16-bit length of network configuration dictionary chunk>
* <[...] network configuration dictionary (may be incomplete)>
* <[1] 8-bit flags>
* <[8] 64-bit config update ID (should never be 0)>
* <[4] 32-bit total length of assembled dictionary>
* <[4] 32-bit index of chunk>
* [ ... end signed portion ... ]
* <[1] 8-bit chunk signature type>
* <[2] 16-bit length of chunk signature>
* <[...] chunk signature>
*
* This is a direct push variant for network config updates. It otherwise
* carries the same payload as OK(NETWORK_CONFIG_REQUEST) and has the same
* semantics.
*
* The legacy mode missing the additional chunking fields is not supported
* here.
*
* Flags:
* 0x01 - Use fast propagation
*
* An OK should be sent if the config is successfully received and
* accepted.
*
* OK payload:
* <[8] 64-bit network ID>
* <[8] 64-bit config update ID>
*/
VERB_NETWORK_CONFIG = 0x0c,
/**
* Request endpoints for multicast distribution:
* <[8] 64-bit network ID>
* <[1] flags>
* <[6] MAC address of multicast group being queried>
* <[4] 32-bit ADI for multicast group being queried>
* <[4] 32-bit requested max number of multicast peers>
* [<[...] network certificate of membership>]
*
* Flags:
* 0x01 - COM is attached
*
* This message asks a peer for additional known endpoints that have
* LIKEd a given multicast group. It's sent when the sender wishes
* to send multicast but does not have the desired number of recipient
* peers.
*
* More than one OK response can occur if the response is broken up across
* multiple packets or if querying a clustered node.
*
* The COM should be included so that upstream nodes that are not
* members of our network can validate our request.
*
* OK response payload:
* <[8] 64-bit network ID>
* <[6] MAC address of multicast group being queried>
* <[4] 32-bit ADI for multicast group being queried>
* [begin gather results -- these same fields can be in OK(MULTICAST_FRAME)]
* <[4] 32-bit total number of known members in this multicast group>
* <[2] 16-bit number of members enumerated in this packet>
* <[...] series of 5-byte ZeroTier addresses of enumerated members>
*
* ERROR is not generated; queries that return no response are dropped.
*/
VERB_MULTICAST_GATHER = 0x0d,
/**
* Multicast frame:
* <[8] 64-bit network ID>
* <[1] flags>
* [<[4] 32-bit implicit gather limit>]
* [<[6] source MAC>]
* <[6] destination MAC (multicast address)>
* <[4] 32-bit multicast ADI (multicast address extension)>
* <[2] 16-bit ethertype>
* <[...] ethernet payload>
*
* Flags:
* 0x01 - Network certificate of membership attached (DEPRECATED)
* 0x02 - Implicit gather limit field is present
* 0x04 - Source MAC is specified -- otherwise it's computed from sender
* 0x08 - Please replicate (sent to multicast replicators)
*
* OK and ERROR responses are optional. OK may be generated if there are
* implicit gather results or if the recipient wants to send its own
* updated certificate of network membership to the sender. ERROR may be
* generated if a certificate is needed or if multicasts to this group
* are no longer wanted (multicast unsubscribe).
*
* OK response payload:
* <[8] 64-bit network ID>
* <[6] MAC address of multicast group>
* <[4] 32-bit ADI for multicast group>
* <[1] flags>
* [<[...] network certificate of membership (DEPRECATED)>]
* [<[...] implicit gather results if flag 0x01 is set>]
*
* OK flags (same bits as request flags):
* 0x01 - OK includes certificate of network membership (DEPRECATED)
* 0x02 - OK includes implicit gather results
*
* ERROR response payload:
* <[8] 64-bit network ID>
* <[6] multicast group MAC>
* <[4] 32-bit multicast group ADI>
*/
VERB_MULTICAST_FRAME = 0x0e,
/**
* Push of potential endpoints for direct communication:
* <[2] 16-bit number of paths>
* <[...] paths>
*
* Path record format:
* <[1] 8-bit path flags>
* <[2] length of extended path characteristics or 0 for none>
* <[...] extended path characteristics>
* <[1] address type>
* <[1] address length in bytes>
* <[...] address>
*
* Path record flags:
* 0x01 - Forget this path if currently known (not implemented yet)
* 0x02 - Cluster redirect -- use this in preference to others
*
* The receiver may, upon receiving a push, attempt to establish a
* direct link to one or more of the indicated addresses. It is the
* responsibility of the sender to limit which peers it pushes direct
* paths to to those with whom it has a trust relationship. The receiver
* must obey any restrictions provided such as exclusivity or blacklists.
* OK responses to this message are optional.
*
* Note that a direct path push does not imply that learned paths can't
* be used unless they are blacklisted explicitly or unless flag 0x01
* is set.
*
* OK and ERROR are not generated.
*/
VERB_PUSH_DIRECT_PATHS = 0x10,
// 0x11 -- deprecated
/**
* An acknowledgment of receipt of a series of recent packets from another
* peer. This is used to calculate relative throughput values and to detect
* packet loss. Only VERB_FRAME and VERB_EXT_FRAME packets are counted.
*
* ACK response format:
* <[4] 32-bit number of bytes received since last ACK>
*
* Upon receipt of this packet, the local peer will verify that the correct
* number of bytes were received by the remote peer. If these values do
* not agree that could be an indication of packet loss.
*
* Additionally, the local peer knows the interval of time that has
* elapsed since the last received ACK. With this information it can compute
* a rough estimate of the current throughput.
*
* This is sent at a maximum rate of once per every ZT_QOS_ACK_INTERVAL
*/
VERB_ACK = 0x12,
/**
* A packet containing timing measurements useful for estimating path quality.
* Composed of a list of <packet ID:internal sojourn time> pairs for an
* arbitrary set of recent packets. This is used to sample for latency and
* packet delay variance (PDV, "jitter").
*
* QoS record format:
*
* <[8] 64-bit packet ID of previously-received packet>
* <[1] 8-bit packet sojourn time>
* <...repeat until end of max 1400 byte packet...>
*
* The number of possible records per QoS packet is: (1400 * 8) / 72 = 155
* This packet should be sent very rarely (every few seconds) as it can be
* somewhat large if the connection is saturated. Future versions might use
* a bloom table to probabilistically determine these values in a vastly
* more space-efficient manner.
*
* Note: The 'internal packet sojourn time' is a slight misnomer as it is a
* measure of the amount of time between when a packet was received and the
* egress time of its tracking QoS packet.
*
* This is sent at a maximum rate of once per every
* ZT_QOS_MEASUREMENT_INTERVAL
*/
VERB_QOS_MEASUREMENT = 0x13,
/**
* A message with arbitrary user-definable content:
* <[8] 64-bit arbitrary message type ID>
* [<[...] message payload>]
*
* This can be used to send arbitrary messages over VL1. It generates no
* OK or ERROR and has no special semantics outside of whatever the user
* (via the ZeroTier core API) chooses to give it.
*
* Message type IDs less than or equal to 65535 are reserved for use by
* ZeroTier, Inc. itself. We recommend making up random ones for your own
* implementations.
*/
VERB_USER_MESSAGE = 0x14,
/**
* A trace for remote debugging or diagnostics:
* <[...] null-terminated dictionary containing trace information>
* [<[...] additional null-terminated dictionaries>]
*
* This message contains a remote trace event. Remote trace events can
* be sent to observers configured at the network level for those that
* pertain directly to activity on a network, or to global observers if
* locally configured.
*
* The instance ID is a random 64-bit value generated by each ZeroTier
* node on startup. This is helpful in identifying traces from different
* members of a cluster.
*/
VERB_REMOTE_TRACE = 0x15,
/**
* A request to a peer to use a specific path in a multi-path scenario:
* <[2] 16-bit unsigned integer that encodes a path choice utility>
*
* This is sent when a node operating in multipath mode observes that
* its inbound and outbound traffic aren't going over the same path. The
* node will compute its perceived utility for using its chosen outbound
* path and send this to a peer in an attempt to petition it to send
* its traffic over this same path.
*
* Scenarios:
*
* (1) Remote peer utility is GREATER than ours:
* - Remote peer will refuse the petition and continue using current path
* (2) Remote peer utility is LESS than than ours:
* - Remote peer will accept the petition and switch to our chosen path
* (3) Remote peer utility is EQUAL to our own:
* - To prevent confusion and flapping, both side will agree to use the
* numerical values of their identities to determine which path to use.
* The peer with the greatest identity will win.
*
* If a node petitions a peer repeatedly with no effect it will regard
* that as a refusal by the remote peer, in this case if the utility is
* negligible it will voluntarily switch to the remote peer's chosen path.
*/
VERB_PATH_NEGOTIATION_REQUEST = 0x16
};
/**
* Error codes for VERB_ERROR
*/
enum ErrorCode
{
/* No error, not actually used in transit */
ERROR_NONE = 0x00,
/* Invalid request */
ERROR_INVALID_REQUEST = 0x01,
/* Bad/unsupported protocol version */
ERROR_BAD_PROTOCOL_VERSION = 0x02,
/* Unknown object queried */
ERROR_OBJ_NOT_FOUND = 0x03,
/* HELLO pushed an identity whose address is already claimed */
ERROR_IDENTITY_COLLISION = 0x04,
/* Verb or use case not supported/enabled by this node */
ERROR_UNSUPPORTED_OPERATION = 0x05,
/* Network membership certificate update needed */
ERROR_NEED_MEMBERSHIP_CERTIFICATE = 0x06,
/* Tried to join network, but you're not a member */
ERROR_NETWORK_ACCESS_DENIED_ = 0x07, /* extra _ at end to avoid Windows name conflict */
/* Multicasts to this group are not wanted */
ERROR_UNWANTED_MULTICAST = 0x08,
/* Network requires external or 2FA authentication (e.g. SSO). */
ERROR_NETWORK_AUTHENTICATION_REQUIRED = 0x09
};
template<unsigned int C2>
Packet(const Buffer<C2> &b) :
Buffer<ZT_PROTO_MAX_PACKET_LENGTH>(b)
{
}
Packet(const void *data,unsigned int len) :
Buffer<ZT_PROTO_MAX_PACKET_LENGTH>(data,len)
{
}
/**
* Construct a new empty packet with a unique random packet ID
*
* Flags and hops will be zero. Other fields and data region are undefined.
* Use the header access methods (setDestination() and friends) to fill out
* the header. Payload should be appended; initial size is header size.
*/
Packet() :
Buffer<ZT_PROTO_MAX_PACKET_LENGTH>(ZT_PROTO_MIN_PACKET_LENGTH)
{
Utils::getSecureRandom(field(ZT_PACKET_IDX_IV,8),8);
(*this)[ZT_PACKET_IDX_FLAGS] = 0; // zero flags, cipher ID, and hops
}
/**
* Make a copy of a packet with a new initialization vector and destination address
*
* This can be used to take one draft prototype packet and quickly make copies to
* encrypt for different destinations.
*
* @param prototype Prototype packet
* @param dest Destination ZeroTier address for new packet
*/
Packet(const Packet &prototype,const Address &dest) :
Buffer<ZT_PROTO_MAX_PACKET_LENGTH>(prototype)
{
Utils::getSecureRandom(field(ZT_PACKET_IDX_IV,8),8);
setDestination(dest);
}
/**
* Construct a new empty packet with a unique random packet ID
*
* @param dest Destination ZT address
* @param source Source ZT address
* @param v Verb
*/
Packet(const Address &dest,const Address &source,const Verb v) :
Buffer<ZT_PROTO_MAX_PACKET_LENGTH>(ZT_PROTO_MIN_PACKET_LENGTH)
{
Utils::getSecureRandom(field(ZT_PACKET_IDX_IV,8),8);
setDestination(dest);
setSource(source);
(*this)[ZT_PACKET_IDX_FLAGS] = 0; // zero flags and hops
setVerb(v);
}
/**
* Reset this packet structure for reuse in place
*
* @param dest Destination ZT address
* @param source Source ZT address
* @param v Verb
*/
inline void reset(const Address &dest,const Address &source,const Verb v)
{
setSize(ZT_PROTO_MIN_PACKET_LENGTH);
Utils::getSecureRandom(field(ZT_PACKET_IDX_IV,8),8);
setDestination(dest);
setSource(source);
(*this)[ZT_PACKET_IDX_FLAGS] = 0; // zero flags, cipher ID, and hops
setVerb(v);
}
/**
* Generate a new IV / packet ID in place
*
* This can be used to re-use a packet buffer multiple times to send
* technically different but otherwise identical copies of the same
* packet.
*/
inline void newInitializationVector() { Utils::getSecureRandom(field(ZT_PACKET_IDX_IV,8),8); }
/**
* Set this packet's destination
*
* @param dest ZeroTier address of destination
*/
inline void setDestination(const Address &dest) { dest.copyTo(field(ZT_PACKET_IDX_DEST,ZT_ADDRESS_LENGTH),ZT_ADDRESS_LENGTH); }
/**
* Set this packet's source
*
* @param source ZeroTier address of source
*/
inline void setSource(const Address &source) { source.copyTo(field(ZT_PACKET_IDX_SOURCE,ZT_ADDRESS_LENGTH),ZT_ADDRESS_LENGTH); }
/**
* Get this packet's destination
*
* @return Destination ZT address
*/
inline Address destination() const { return Address(field(ZT_PACKET_IDX_DEST,ZT_ADDRESS_LENGTH),ZT_ADDRESS_LENGTH); }
/**
* Get this packet's source
*
* @return Source ZT address
*/
inline Address source() const { return Address(field(ZT_PACKET_IDX_SOURCE,ZT_ADDRESS_LENGTH),ZT_ADDRESS_LENGTH); }
/**
* @return True if packet is of valid length
*/
inline bool lengthValid() const { return (size() >= ZT_PROTO_MIN_PACKET_LENGTH); }
/**
* @return True if packet is fragmented (expect fragments)
*/
inline bool fragmented() const { return (((unsigned char)(*this)[ZT_PACKET_IDX_FLAGS] & ZT_PROTO_FLAG_FRAGMENTED) != 0); }
/**
* Set this packet's fragmented flag
*
* @param f Fragmented flag value
*/
inline void setFragmented(bool f)
{
if (f) {
(*this)[ZT_PACKET_IDX_FLAGS] |= (char)ZT_PROTO_FLAG_FRAGMENTED;
} else {
(*this)[ZT_PACKET_IDX_FLAGS] &= (char)(~ZT_PROTO_FLAG_FRAGMENTED);
}
}
/**
* @return True if compressed (result only valid if unencrypted)
*/
inline bool compressed() const { return (((unsigned char)(*this)[ZT_PACKET_IDX_VERB] & ZT_PROTO_VERB_FLAG_COMPRESSED) != 0); }
/**
* @return ZeroTier forwarding hops (0 to 7)
*/
inline unsigned int hops() const { return ((unsigned int)(*this)[ZT_PACKET_IDX_FLAGS] & 0x07); }
/**
* Increment this packet's hop count
*/
inline void incrementHops()
{
unsigned char &b = (*this)[ZT_PACKET_IDX_FLAGS];
b = (b & 0xf8) | ((b + 1) & 0x07);
}
/**
* @return Cipher suite selector: 0 - 7 (see #defines)
*/
inline unsigned int cipher() const
{
return (((unsigned int)(*this)[ZT_PACKET_IDX_FLAGS] & 0x38) >> 3);
}
/**
* @return Whether this packet is currently encrypted
*/
inline bool isEncrypted() const
{
return (cipher() == ZT_PROTO_CIPHER_SUITE__C25519_POLY1305_SALSA2012) || (cipher() == ZT_PROTO_CIPHER_SUITE__AES_GMAC_SIV);
}
/**
* Set this packet's cipher suite
*/
inline void setCipher(unsigned int c)
{
unsigned char &b = (*this)[ZT_PACKET_IDX_FLAGS];
b = (b & 0xc7) | (unsigned char)((c << 3) & 0x38); // bits: FFCCCHHH
// Set DEPRECATED "encrypted" flag -- used by pre-1.0.3 peers
if (c == ZT_PROTO_CIPHER_SUITE__C25519_POLY1305_SALSA2012) {
b |= ZT_PROTO_FLAG_ENCRYPTED;
} else {
b &= (~ZT_PROTO_FLAG_ENCRYPTED);
}
}
/**
* Get the trusted path ID for this packet (only meaningful if cipher is trusted path)
*
* @return Trusted path ID (from MAC field)
*/
inline uint64_t trustedPathId() const { return at<uint64_t>(ZT_PACKET_IDX_MAC); }
/**
* Set this packet's trusted path ID and set the cipher spec to trusted path
*
* @param tpid Trusted path ID
*/
inline void setTrusted(const uint64_t tpid)
{
setCipher(ZT_PROTO_CIPHER_SUITE__NO_CRYPTO_TRUSTED_PATH);
setAt(ZT_PACKET_IDX_MAC,tpid);
}
/**
* Get this packet's unique ID (the IV field interpreted as uint64_t)
*
* Note that the least significant 3 bits of this ID will change when armor()
* is called to armor the packet for transport. This is because armor() will
* mask the last 3 bits against the send counter for QoS monitoring use prior
* to actually using the IV to encrypt and MAC the packet. Be aware of this
* when grabbing the packetId of a new packet prior to armor/send.
*
* @return Packet ID
*/
inline uint64_t packetId() const { return at<uint64_t>(ZT_PACKET_IDX_IV); }
/**
* Set packet verb
*
* This also has the side-effect of clearing any verb flags, such as
* compressed, and so must only be done during packet composition.
*
* @param v New packet verb
*/
inline void setVerb(Verb v) { (*this)[ZT_PACKET_IDX_VERB] = (char)v; }
/**
* @return Packet verb (not including flag bits)
*/
inline Verb verb() const { return (Verb)((*this)[ZT_PACKET_IDX_VERB] & 0x1f); }
/**
* @return Length of packet payload
*/
inline unsigned int payloadLength() const { return ((size() < ZT_PROTO_MIN_PACKET_LENGTH) ? 0 : (size() - ZT_PROTO_MIN_PACKET_LENGTH)); }
/**
* @return Raw packet payload
*/
inline const unsigned char *payload() const { return field(ZT_PACKET_IDX_PAYLOAD,size() - ZT_PACKET_IDX_PAYLOAD); }
/**
* Armor packet for transport
*
* @param key 32-byte key
* @param encryptPayload If true, encrypt packet payload, else just MAC
* @param aesKeys If non-NULL these are the two keys for AES-GMAC-SIV
*/
void armor(const void *key,bool encryptPayload,const AES aesKeys[2]);
/**
* Verify and (if encrypted) decrypt packet
*
* This does not handle trusted path mode packets and will return false
* for these. These are handled in IncomingPacket if the sending physical
* address and MAC field match a trusted path.
*
* @param key 32-byte key
* @param aesKeys If non-NULL these are the two keys for AES-GMAC-SIV
* @return False if packet is invalid or failed MAC authenticity check
*/
bool dearmor(const void *key,const AES aesKeys[2]);
/**
* Encrypt/decrypt a separately armored portion of a packet
*
* This is currently only used to mask portions of HELLO as an extra
* security precaution since most of that message is sent in the clear.
*
* This must NEVER be used more than once in the same packet, as doing
* so will result in re-use of the same key stream.
*
* @param key 32-byte key
* @param start Start of encrypted portion
* @param len Length of encrypted portion
*/
void cryptField(const void *key,unsigned int start,unsigned int len);
/**
* Attempt to compress payload if not already (must be unencrypted)
*
* This requires that the payload at least contain the verb byte already
* set. The compressed flag in the verb is set if compression successfully
* results in a size reduction. If no size reduction occurs, compression
* is not done and the flag is left cleared.
*
* @return True if compression occurred
*/
bool compress();
/**
* Attempt to decompress payload if it is compressed (must be unencrypted)
*
* If payload is compressed, it is decompressed and the compressed verb
* flag is cleared. Otherwise nothing is done and true is returned.
*
* @return True if data is now decompressed and valid, false on error
*/
bool uncompress();
private:
static const unsigned char ZERO_KEY[32];
/**
* Deterministically mangle a 256-bit crypto key based on packet
*
* This uses extra data from the packet to mangle the secret, giving us an
* effective IV that is somewhat more than 64 bits. This is "free" for
* Salsa20 since it has negligible key setup time so using a different
* key each time is fine.
*
* @param in Input key (32 bytes)
* @param out Output buffer (32 bytes)
*/
inline void _salsa20MangleKey(const unsigned char *in,unsigned char *out) const
{
const unsigned char *d = (const unsigned char *)data();
// IV and source/destination addresses. Using the addresses divides the
// key space into two halves-- A->B and B->A (since order will change).
for(unsigned int i=0;i<18;++i) { // 8 + (ZT_ADDRESS_LENGTH * 2) == 18
out[i] = in[i] ^ d[i];
}
// Flags, but with hop count masked off. Hop count is altered by forwarding
// nodes. It's one of the only parts of a packet modifiable by people
// without the key.
out[18] = in[18] ^ (d[ZT_PACKET_IDX_FLAGS] & 0xf8);
// Raw packet size in bytes -- thus each packet size defines a new
// key space.
out[19] = in[19] ^ (unsigned char)(size() & 0xff);
out[20] = in[20] ^ (unsigned char)((size() >> 8) & 0xff); // little endian
// Rest of raw key is used unchanged
for(unsigned int i=21;i<32;++i) {
out[i] = in[i];
}
}
};
} // namespace ZeroTier
#endif
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