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https://github.com/zerotier/ZeroTierOne.git
synced 2024-12-19 04:57:53 +00:00
Documentation in Packet, more work on path push, and clean up ancient legacy support code in Switch.
This commit is contained in:
Adam Ierymenko
parent
df08c2cfab
commit
e5f7c55c54
@ -595,9 +595,7 @@ bool IncomingPacket::_doEXT_FRAME(const RuntimeEnvironment *RR,const SharedPtr<P
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TRACE("dropped EXT_FRAME from %s@%s(%s) to %s: sender not allowed to bridge into %.16llx",from.toString().c_str(),peer->address().toString().c_str(),_remoteAddress.toString().c_str(),to.toString().c_str(),network->id());
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return true;
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}
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}
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if (to != network->mac()) {
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} else if (to != network->mac()) {
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if (!network->permitsBridging(RR->identity.address())) {
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TRACE("dropped EXT_FRAME from %s@%s(%s) to %s: I cannot bridge to %.16llx or bridging disabled on network",from.toString().c_str(),peer->address().toString().c_str(),_remoteAddress.toString().c_str(),to.toString().c_str(),network->id());
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return true;
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@ -51,7 +51,7 @@ const char *Packet::verbString(Verb v)
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case VERB_MULTICAST_GATHER: return "MULTICAST_GATHER";
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case VERB_MULTICAST_FRAME: return "MULTICAST_FRAME";
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case VERB_SET_EPHEMERAL_KEY: return "SET_EPHEMERAL_KEY";
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case VERB_PHYSICAL_ADDRESS_PUSH: return "PHYSICAL_ADDRESS_PUSH";
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case VERB_PUSH_DIRECT_PATHS: return "PUSH_DIRECT_PATHS";
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}
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return "(unknown)";
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}
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132
node/Packet.hpp
132
node/Packet.hpp
@ -71,13 +71,14 @@
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/**
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* Maximum hop count allowed by packet structure (3 bits, 0-7)
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*
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* This is not necessarily the maximum hop counter after which
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* relaying is no longer performed.
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* This is a protocol constant. It's the maximum allowed by the length
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* of the hop counter -- three bits. See node/Constants.hpp for the
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* pragmatic forwarding limit, which is typically lower.
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*/
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#define ZT_PROTO_MAX_HOPS 7
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/**
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* Cipher suite: Curve25519/Poly1305/Salsa20/12 without payload encryption
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* Cipher suite: Curve25519/Poly1305/Salsa20/12/NOCRYPT
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*
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* This specifies Poly1305 MAC using a 32-bit key derived from the first
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* 32 bytes of a Salsa20/12 keystream as in the Salsa20/12 cipher suite,
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@ -103,9 +104,7 @@
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*
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* This message is encrypted with the latest negotiated ephemeral (PFS)
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* key pair and cipher suite. If authentication fails, VERB_SET_EPHEMERAL_KEY
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* may be sent to renegotiate ephemeral keys. To prevent attacks, this
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* attempted renegotiation should be limited to some sane rate such as
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* once per second.
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* may be sent to renegotiate ephemeral keys.
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*/
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#define ZT_PROTO_CIPHER_SUITE__EPHEMERAL 7
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@ -113,7 +112,7 @@
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* DEPRECATED payload encrypted flag, will be removed for re-use soon.
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*
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* This has been replaced by the two-bit cipher suite selection field where
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* a value of 0 indicated unencrypted (but authenticated) messages.
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* a value of 0 indicates unencrypted (but authenticated) messages.
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*/
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#define ZT_PROTO_FLAG_ENCRYPTED 0x80
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@ -132,11 +131,68 @@
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/**
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* Rounds used for Salsa20 encryption in ZT
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*
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* Discussion:
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*
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* DJB (Salsa20's designer) designed Salsa20 with a significant margin of 20
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* rounds, but has said repeatedly that 12 is likely sufficient. So far (as of
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* July 2015) there are no published attacks against 12 rounds, let alone 20.
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*
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* In cryptography, a "break" means something different from what it means in
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* common discussion. If a cipher is 256 bits strong and someone finds a way
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* to reduce key search to 254 bits, this constitues a "break" in the academic
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* literature. 254 bits is still far beyond what can be leveraged to accomplish
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* a "break" as most people would understand it -- the actual decryption and
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* reading of traffic.
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*
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* Nevertheless, "attacks only get better" as cryptographers like to say. As
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* a result, they recommend not using anything that's shown any weakness even
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* if that weakness is so far only meaningful to academics. It may be a sign
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* of a deeper problem.
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*
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* So why choose a lower round count?
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*
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* Turns out the speed difference is nontrivial. On a Macbook Pro (Core i3) 20
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* rounds of SSE-optimized Salsa20 achieves ~508mb/sec/core, while 12 rounds
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* hits ~832mb/sec/core. ZeroTier is designed for multiple objectives:
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* security, simplicity, and performance. In this case a deference was made
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* for performance.
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*
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* Meta discussion:
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*
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* The cipher is not the thing you should be paranoid about.
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*
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* I'll qualify that. If the cipher is known to be weak, like RC4, or has a
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* key size that is too small, like DES, then yes you should worry about
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* the cipher.
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*
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* But if the cipher is strong and your adversary is anyone other than the
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* intelligence apparatus of a major superpower, you are fine in that
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* department.
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*
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* Go ahead. Search for the last ten vulnerabilities discovered in SSL. Not
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* a single one involved the breaking of a cipher. Now broaden your search.
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* Look for issues with SSH, IPSec, etc. The only cipher-related issues you
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* will find might involve the use of RC4 or MD5, algorithms with known
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* issues or small key/digest sizes. But even weak ciphers are difficult to
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* exploit in the real world -- you usually need a lot of data and a lot of
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* compute time. No, virtually EVERY security vulnerability you will find
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* involves a problem with the IMPLEMENTATION not with the cipher.
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*
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* A flaw in ZeroTier's protocol or code is incredibly, unbelievably
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* more likely than a flaw in Salsa20 or any other cipher or cryptographic
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* primitive it uses. We're talking odds of dying in a car wreck vs. odds of
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* being personally impacted on the head by a meteorite. Nobody without a
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* billion dollar budget is going to break into your network by actually
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* cracking Salsa20/12 (or even /8) in the field.
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*
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* So stop worrying about the cipher unless you are, say, the Kremlin and your
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* adversary is the NSA and the GCHQ. In that case... well that's above my
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* pay grade. I'll just say defense in depth.
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*/
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#define ZT_PROTO_SALSA20_ROUNDS 12
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// Indices of fields in normal packet header -- do not change as this
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// might require both code rework and will break compatibility.
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// Field indexes in packet header
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#define ZT_PACKET_IDX_IV 0
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#define ZT_PACKET_IDX_DEST 8
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#define ZT_PACKET_IDX_SOURCE 13
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@ -147,16 +203,19 @@
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/**
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* Packet buffer size (can be changed)
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*
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* The current value is big enough for ZT_MAX_PACKET_FRAGMENTS, the pragmatic
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* packet fragment limit, times the default UDP MTU. Most packets won't be
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* this big.
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*/
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#define ZT_PROTO_MAX_PACKET_LENGTH (ZT_MAX_PACKET_FRAGMENTS * ZT_UDP_DEFAULT_PAYLOAD_MTU)
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/**
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* Minimum viable packet length (also length of header)
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* Minimum viable packet length (a.k.a. header length)
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*/
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#define ZT_PROTO_MIN_PACKET_LENGTH ZT_PACKET_IDX_PAYLOAD
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// Indexes of fields in fragment header -- also can't be changed without
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// breaking compatibility.
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// Indexes of fields in fragment header
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#define ZT_PACKET_FRAGMENT_IDX_PACKET_ID 0
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#define ZT_PACKET_FRAGMENT_IDX_DEST 8
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#define ZT_PACKET_FRAGMENT_IDX_FRAGMENT_INDICATOR 13
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@ -165,7 +224,7 @@
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#define ZT_PACKET_FRAGMENT_IDX_PAYLOAD 16
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/**
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* Value found at ZT_PACKET_FRAGMENT_IDX_FRAGMENT_INDICATOR in fragments
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* Magic number found at ZT_PACKET_FRAGMENT_IDX_FRAGMENT_INDICATOR
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*/
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#define ZT_PACKET_FRAGMENT_INDICATOR ZT_ADDRESS_RESERVED_PREFIX
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@ -175,23 +234,26 @@
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#define ZT_PROTO_MIN_FRAGMENT_LENGTH ZT_PACKET_FRAGMENT_IDX_PAYLOAD
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/**
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* Length of LAN beacon packets
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* DEPRECATED: length of LAN beacon packets
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*/
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#define ZT_PROTO_BEACON_LENGTH 13
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/**
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* Index of address in a LAN beacon
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* DEPRECATED: index of address in a LAN beacon
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*/
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#define ZT_PROTO_BEACON_IDX_ADDRESS 8
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// Destination address types from HELLO and OK(HELLO)
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// Destination address types from HELLO, OK(HELLO), and other message types
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#define ZT_PROTO_DEST_ADDRESS_TYPE_NONE 0
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#define ZT_PROTO_DEST_ADDRESS_TYPE_ETHERNET 1
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#define ZT_PROTO_DEST_ADDRESS_TYPE_ZEROTIER 1 // reserved but unused
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#define ZT_PROTO_DEST_ADDRESS_TYPE_ETHERNET 2 // future use
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#define ZT_PROTO_DEST_ADDRESS_TYPE_BLUETOOTH 3 // future use
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#define ZT_PROTO_DEST_ADDRESS_TYPE_IPV4 4
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#define ZT_PROTO_DEST_ADDRESS_TYPE_LTE_DIRECT 5 // future use
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#define ZT_PROTO_DEST_ADDRESS_TYPE_IPV6 6
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// Ephemeral key record flags
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#define ZT_PROTO_EPHEMERAL_KEY_FLAG_FIPS 0x01
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#define ZT_PROTO_EPHEMERAL_KEY_FLAG_FIPS 0x01 // future use
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// Ephemeral key record symmetric cipher types
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#define ZT_PROTO_EPHEMERAL_KEY_SYMMETRIC_CIPHER_SALSA2012_POLY1305 0x01
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@ -680,10 +742,8 @@ public:
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/* Network configuration refresh request:
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* <[...] array of 64-bit network IDs>
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*
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* This message can be sent by the network configuration master node
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* to request that nodes refresh their network configuration. It can
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* thus be used to "push" updates so that network config changes will
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* take effect quickly.
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* This can be sent by the network controller to inform a node that it
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* should now make a NETWORK_CONFIG_REQUEST.
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*
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* It does not generate an OK or ERROR message, and is treated only as
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* a hint to refresh now.
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@ -769,7 +829,7 @@ public:
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*/
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VERB_MULTICAST_FRAME = 14,
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/* Ephemeral (PFS) key push:
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/* Ephemeral (PFS) key push: (UNFINISHED, NOT IMPLEMENTED YET)
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* <[2] flags (unused and reserved, must be 0)>
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* <[2] length of padding / extra field section>
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* <[...] padding / extra field section>
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@ -826,21 +886,35 @@ public:
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VERB_SET_EPHEMERAL_KEY = 15,
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/* Push of potential endpoints for direct communication:
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* <[1] flags (unused, must be zero)>
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* <[2] 16-bit number of paths>
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* <[...] paths>
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*
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* Path record format:
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* <[1] flags>
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* <[2] number of addresses>
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* <[...] address types and addresses>
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* <[1] metric from 0 (highest priority) to 255 (lowest priority)>
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* <[1] address type>
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* <[...] address>
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*
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* Path record flags:
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* 0x01 - Blacklist this path, do not use
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* 0x02 - Reliable path (no keepalives, etc. necessary)
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* 0x04 - Trusted path (encryption and authentication optional)
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*
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* None of the above flags are implemented yet as of 1.0.4. They're
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* reserved for future use.
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*
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* Address types and addresses are of the same format as the destination
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* address type and address in HELLO.
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*
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* The receiver may, upon receiving a push, attempt to establish a
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* direct link to one or more of the indicated addresses. Senders should
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* only send address pushes to peers that they have some relationship
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* with such as a shared network membership or a mutual trust.
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* direct link to one or more of the indicated addresses. It is the
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* responsibility of the sender to limit which peers it pushes direct
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* paths to to those with whom it has a trust relationship.
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*
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* OK/ERROR are not generated.
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*/
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VERB_PHYSICAL_ADDRESS_PUSH = 16
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VERB_PUSH_DIRECT_PATHS = 16
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};
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/**
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@ -167,6 +167,8 @@ void Switch::onLocalEthernet(const SharedPtr<Network> &network,const MAC &from,c
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Address toZT(to.toAddress(network->id()));
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if (network->isAllowed(toZT)) {
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const bool includeCom = network->peerNeedsOurMembershipCertificate(toZT,RR->node->now());
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/*
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if (network->peerNeedsOurMembershipCertificate(toZT,RR->node->now())) {
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// TODO: once there are no more <1.0.0 nodes around, we can
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// bundle this with EXT_FRAME instead of sending two packets.
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@ -174,12 +176,17 @@ void Switch::onLocalEthernet(const SharedPtr<Network> &network,const MAC &from,c
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nconf->com().serialize(outp);
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send(outp,true,network->id());
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}
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*/
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if (fromBridged) {
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// EXT_FRAME is used for bridging or if we want to include a COM
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if ((true)||(fromBridged)||(includeCom)) {
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Packet outp(toZT,RR->identity.address(),Packet::VERB_EXT_FRAME);
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outp.append(network->id());
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outp.append((unsigned char)0);
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if (includeCom) {
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outp.append((unsigned char)0x01); // 0x01 -- COM included
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nconf->com().serialize(outp);
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} else {
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outp.append((unsigned char)0x00);
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}
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to.appendTo(outp);
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from.appendTo(outp);
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outp.append((uint16_t)etherType);
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@ -187,7 +194,6 @@ void Switch::onLocalEthernet(const SharedPtr<Network> &network,const MAC &from,c
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outp.compress();
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send(outp,true,network->id());
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} else {
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// FRAME is a shorter version that can be used when there's no bridging and no COM
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Packet outp(toZT,RR->identity.address(),Packet::VERB_FRAME);
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outp.append(network->id());
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outp.append((uint16_t)etherType);
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@ -196,7 +202,7 @@ void Switch::onLocalEthernet(const SharedPtr<Network> &network,const MAC &from,c
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send(outp,true,network->id());
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}
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//TRACE("%.16llx: UNICAST: %s -> %s etherType==%s(%.4x) vlanId==%u len==%u fromBridged==%d",network->id(),from.toString().c_str(),to.toString().c_str(),etherTypeName(etherType),etherType,vlanId,len,(int)fromBridged);
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//TRACE("%.16llx: UNICAST: %s -> %s etherType==%s(%.4x) vlanId==%u len==%u fromBridged==%d includeCom==%d",network->id(),from.toString().c_str(),to.toString().c_str(),etherTypeName(etherType),etherType,vlanId,len,(int)fromBridged,(int)includeCom);
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} else {
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TRACE("%.16llx: UNICAST: %s -> %s etherType==%s dropped, destination not a member of private network",network->id(),from.toString().c_str(),to.toString().c_str(),etherTypeName(etherType));
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}
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