mirror of
https://github.com/monero-project/monero.git
synced 2024-11-18 00:37:43 +00:00
165 lines
6.9 KiB
Markdown
165 lines
6.9 KiB
Markdown
# Levin Protocol
|
|
This is a document explaining the current design of the levin protocol, as
|
|
used by Monero. The protocol is largely inherited from cryptonote, but has
|
|
undergone some changes.
|
|
|
|
This document also may differ from the `struct bucket_head2` in Monero's
|
|
code slightly - the spec here is slightly more strict to allow for
|
|
extensibility.
|
|
|
|
One of the goals of this document is to clearly indicate what is being sent
|
|
"on the wire" to identify metadata that could de-anonymize users over I2P/Tor.
|
|
These issues will be addressed as they are found. See `ANONMITY_NETWORKS.md` in
|
|
the top-level folder for any outstanding issues.
|
|
|
|
> This document does not currently list all data being sent by the monero
|
|
> protocol, that portion is a work-in-progress. Please take the time to do it
|
|
> if interested in learning about Monero p2p traffic!
|
|
|
|
|
|
## Header
|
|
This header is sent for every Monero p2p message.
|
|
|
|
```
|
|
0 1 2 3
|
|
0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7
|
|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|
|
| 0x01 | 0x21 | 0x01 | 0x01 |
|
|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|
|
| 0x01 | 0x01 | 0x01 | 0x01 |
|
|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|
|
| Length |
|
|
| |
|
|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|
|
| E. Response | Command
|
|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|
|
| Return Code
|
|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|
|
|Q|S|B|E| Reserved
|
|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|
|
| 0x01 | 0x00 | 0x00 |
|
|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|
|
| 0x00 |
|
|
+-+-+-+-+-+-+-+-+
|
|
```
|
|
|
|
### Signature
|
|
The first 8 bytes are the "signature" which helps identify the protocol (in
|
|
case someone connected to the wrong port, etc). The comments indicate that byte
|
|
sequence is from "benders nightmare".
|
|
|
|
This also can be used by deep packet inspection (DPI) engines to identify
|
|
Monero when the link is not encrypted. SSL has been proposed as a means to
|
|
mitigate this issue, but BIP-151 or the Noise protocol should also be considered.
|
|
|
|
### Length
|
|
The length is an unsigned 64-bit little endian integer. The length does _not_
|
|
include the header.
|
|
|
|
The implementation currently rejects received messages that exceed 100 MB
|
|
(base 10) by default.
|
|
|
|
### Expect Response
|
|
A zero-byte if no response is expected from the peer, and a non-zero byte if a
|
|
response is expected from the peer. Peers must respond to requests with this
|
|
flag in the same order that they were received, however, other messages can be
|
|
sent between responses.
|
|
|
|
There are some commands in the
|
|
[cryptonote protocol](#cryptonote-protocol-commands) where a response is
|
|
expected from the peer, but this flag is not set. Those responses are returned
|
|
as notify messages and can be sent in any order by the peer.
|
|
|
|
### Command
|
|
An unsigned 32-bit little endian integer representing the Monero specific
|
|
command being invoked.
|
|
|
|
### Return Code
|
|
A signed 32-bit little integer integer representing the response from the peer
|
|
from the last command that was invoked. This is `0` for request messages.
|
|
|
|
### Flags
|
|
* `Q` - Bit is set if the message is a request.
|
|
* `S` - Bit is set if the message is a response.
|
|
* `B` - Bit is set if this is a the beginning of a [fragmented message](#fragmented-messages).
|
|
* `E` - Bit is set if this is the end of a [fragmented message](#fragmented-messages).
|
|
|
|
### Version
|
|
A fixed value of `1` as an unsigned 32-bit little endian integer.
|
|
|
|
|
|
## Message Flow
|
|
The protocol can be subdivided into: (1) notifications, (2) requests,
|
|
(3) responses, (4) fragmented messages, and (5) dummy messages. Response
|
|
messages must be sent in the same order that a peer issued a request message.
|
|
A peer does not have to send a response immediately following a request - any
|
|
other message type can be sent instead.
|
|
|
|
### Notifications
|
|
Notifications are one-way messages that can be sent at any time without
|
|
an expectation of a response from the peer. The `Q` bit must be set, the `S`,
|
|
`B` and `E` bits must be unset, and the `Expect Response` field must be zeroed.
|
|
|
|
Some notifications must be in response to other notifications. This is not
|
|
part of the levin messaging layer, and is described in the
|
|
[commands](#commands) section.
|
|
|
|
### Requests
|
|
Requests are the basis of the admin protocol for Monero. The `Q` bit must be
|
|
set, the `S`, `B` and `E` bits must be unset, and the `Expect Response` field
|
|
must be non-zero. The peer is expected to send a response message with the same
|
|
`command` number.
|
|
|
|
### Responses
|
|
Response message can only be sent after a peer first issues a request message.
|
|
Responses must have the `S` bit set, the `Q`, `B` and `E` bits unset, and have
|
|
a zeroed `Expect Response` field. The `Command` field must be the same value
|
|
that was sent in the request message. The `Return Code` is specific to the
|
|
`Command` being issued (see [commands])(#commands)).
|
|
|
|
### Fragmented
|
|
Fragmented messages were introduced for the "white noise" feature for i2p/tor.
|
|
A transaction can be sent in fragments to conceal when "real" data is being
|
|
sent instead of dummy messages. Only one fragmented message can be sent at a
|
|
time, and bits `B` and `E` are never set at the same time
|
|
(see [dummy messages](#dummy)). The re-constructed message must contain a
|
|
levin header for a different (non-fragment) message type.
|
|
|
|
The `Q` and `S` bits are never set and the `Expect Response` field must always
|
|
be zero. The first fragment has the `B` bit set, neither `B` nor `E` is set for
|
|
"middle" fragments, and `E` is set for the last fragment.
|
|
|
|
### Dummy
|
|
Dummy messages have the `B` and `E` bits set, the `Q` and `S` bits unset, and
|
|
the `Expect Reponse` field zeroed. When a message of this type is received, the
|
|
contents can be safely ignored.
|
|
|
|
|
|
## Commands
|
|
### P2P (Admin) Commands
|
|
|
|
#### (`1001` Request) Handshake
|
|
#### (`1001` Response) Handshake
|
|
#### (`1002` Request) Timed Sync
|
|
#### (`1002` Response) Timed Sync
|
|
#### (`1003` Request) Ping
|
|
#### (`1003` Response) Ping
|
|
#### (`1004` Request) Stat Info
|
|
#### (`1004` Response) Stat Info
|
|
#### (`1005` Request) Network State
|
|
#### (`1005` Response) Network State
|
|
#### (`1006` Request) Peer ID
|
|
#### (`1006` Reponse) Peer ID
|
|
#### (`1007` Request) Support Flags
|
|
#### (`1007` Response) Support Flags
|
|
|
|
### Cryptonote Protocol Commands
|
|
|
|
#### (`2001` Notification) New Block
|
|
#### (`2002` Notification) New Transactions
|
|
#### (`2003` Notification) Request Get Objects
|
|
#### (`2004` Notification) Response Get Objects
|
|
#### (`2006` Notification) Request Chain
|
|
#### (`2007` Notification) Response Chain Entry
|
|
#### (`2008` Notification) New Fluffy Block
|
|
#### (`2009` Notification) Request Fluffy Missing TX
|