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zebra/zebra-network/src/message.rs

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//! Definitions of network messages.
use std::io::{self, Cursor, Read, Write};
use std::net;
use byteorder::{LittleEndian, ReadBytesExt, WriteBytesExt};
use chrono::{DateTime, TimeZone, Utc};
use tokio::io::{AsyncRead, AsyncReadExt, AsyncWrite, AsyncWriteExt};
use zebra_chain::{
serialization::{
ReadZcashExt, SerializationError, WriteZcashExt, ZcashDeserialize, ZcashSerialize,
},
transaction::Transaction,
types::{BlockHeight, Sha256dChecksum},
};
use crate::meta_addr::MetaAddr;
use crate::types::*;
/// A Bitcoin-like network message for the Zcash protocol.
///
/// The Zcash network protocol is mostly inherited from Bitcoin, and a list of
/// Bitcoin network messages can be found [on the Bitcoin
/// wiki][btc_wiki_protocol].
///
/// That page describes the wire format of the messages, while this enum stores
/// an internal representation. The internal representation is unlinked from the
/// wire format, and the translation between the two happens only during
/// serialization and deserialization. For instance, Bitcoin identifies messages
/// by a 12-byte ascii command string; we consider this a serialization detail
/// and use the enum discriminant instead. (As a side benefit, this also means
/// that we have a clearly-defined validation boundary for network messages
/// during serialization).
///
/// [btc_wiki_protocol]: https://en.bitcoin.it/wiki/Protocol_documentation
//
// XXX not all messages are filled in yet. Messages written as { /* XXX add
// fields */ } are explicitly incomplete and we need to define a mapping between
// the serialized message data and the internal representation. Note that this
// is different from messages like GetAddr which have no data (and so have no
// fields).
#[derive(Clone, Debug, Eq, PartialEq)]
pub enum Message {
/// A `version` message.
///
/// Note that although this is called `version` in Bitcoin, its role is really
/// analogous to a `ClientHello` message in TLS, used to begin a handshake, and
/// is distinct from a simple version number.
///
/// [Bitcoin reference](https://en.bitcoin.it/wiki/Protocol_documentation#version)
Version {
/// The network version number supported by the sender.
version: Version,
/// The network services advertised by the sender.
services: Services,
/// The time when the version message was sent.
timestamp: DateTime<Utc>,
/// The network address of the node receiving this message, and its
/// advertised network services.
///
/// Q: how does the handshake know the remote peer's services already?
address_recv: (Services, net::SocketAddr),
/// The network address of the node sending this message, and its
/// advertised network services.
address_from: (Services, net::SocketAddr),
/// Node random nonce, randomly generated every time a version
/// packet is sent. This nonce is used to detect connections
/// to self.
nonce: Nonce,
/// The Zcash user agent advertised by the sender.
user_agent: String,
/// The last block received by the emitting node.
start_height: BlockHeight,
/// Whether the remote peer should announce relayed
/// transactions or not, see [BIP 0037](https://github.com/bitcoin/bips/blob/master/bip-0037.mediawiki)
relay: bool,
},
/// A `verack` message.
///
/// [Bitcoin reference](https://en.bitcoin.it/wiki/Protocol_documentation#verack)
Verack,
/// A `ping` message.
///
/// [Bitcoin reference](https://en.bitcoin.it/wiki/Protocol_documentation#ping)
Ping(
/// A nonce unique to this [`Ping`] message.
Nonce,
),
/// A `pong` message.
///
/// [Bitcoin reference](https://en.bitcoin.it/wiki/Protocol_documentation#pong)
Pong(
/// The nonce from the [`Ping`] message this was in response to.
Nonce,
),
/// A `reject` message.
///
/// [Bitcoin reference](https://en.bitcoin.it/wiki/Protocol_documentation#reject)
Reject {
/// Type of message rejected.
// Q: can we just reference the Type, rather than instantiate an instance of the enum type?
message: Box<Message>,
/// RejectReason code relating to rejected message.
ccode: RejectReason,
/// Human-readable version of rejection reason.
reason: String,
/// Optional extra data provided for some errors.
// Currently, all errors which provide this field fill it with
// the TXID or block header hash of the object being rejected,
// so the field is 32 bytes.
//
// Q: can we tell Rust that this field is optional? Or just
// default its value to an empty array, I guess.
data: Option<[u8; 32]>,
},
/// An `addr` message.
///
/// [Bitcoin reference](https://en.bitcoin.it/wiki/Protocol_documentation#addr)
Addr(Vec<MetaAddr>),
/// A `getaddr` message.
///
/// [Bitcoin reference](https://en.bitcoin.it/wiki/Protocol_documentation#getaddr)
GetAddr,
/// A `block` message.
///
/// [Bitcoin reference](https://en.bitcoin.it/wiki/Protocol_documentation#block)
Block {/* XXX add fields */},
/// A `getblocks` message.
///
/// [Bitcoin reference](https://en.bitcoin.it/wiki/Protocol_documentation#getblocks)
GetBlocks {/* XXX add fields */},
/// A `headers` message.
///
/// [Bitcoin reference](https://en.bitcoin.it/wiki/Protocol_documentation#headers)
Headers {/* XXX add fields */},
/// A `getheaders` message.
///
/// [Bitcoin reference](https://en.bitcoin.it/wiki/Protocol_documentation#getheaders)
GetHeaders {/* XXX add fields */},
/// An `inv` message.
///
/// [Bitcoin reference](https://en.bitcoin.it/wiki/Protocol_documentation#inv)
// XXX the bitcoin reference above suggests this can be 1.8 MB in bitcoin -- maybe
// larger in Zcash, since Zcash objects could be bigger (?) -- does this tilt towards
// having serialization be async?
Inventory {
/// Number of inventory entries.
count: u64,
/// Inventory vectors.
inventory: Vec<zebra_chain::types::InventoryVector>,
},
/// A `getdata` message.
///
/// `getdata` is used in response to `inv`, to retrieve the content of
/// a specific object, and is usually sent after receiving an `inv`
/// packet, after filtering known elements.
///
/// [Bitcoin reference](https://en.bitcoin.it/wiki/Protocol_documentation#getdata)
GetData {
/// Number of inventory entries.
count: u64,
/// Inventory vectors.
inventory: Vec<zebra_chain::types::InventoryVector>,
},
/// A `notfound` message.
///
/// [Bitcoin reference](https://en.bitcoin.it/wiki/Protocol_documentation#notfound)
// See note above on `Inventory`.
NotFound {
/// Number of inventory entries.
count: u64,
/// Inventory vectors.
inventory: Vec<zebra_chain::types::InventoryVector>,
},
/// A `tx` message.
///
/// [Bitcoin reference](https://en.bitcoin.it/wiki/Protocol_documentation#tx)
// `flag` is not included (it's optional), and therefore
// `tx_witnesses` aren't either, as they go if `flag` goes.
Tx {
/// Transaction data format version (note, this is signed).
version: Version,
/// The `Transaction` type itself.
// XXX Is this ~aesthetic~?
transaction: Transaction,
},
/// A `mempool` message.
///
/// This was defined in [BIP35], which is included in Zcash.
///
/// [Bitcoin reference](https://en.bitcoin.it/wiki/Protocol_documentation#mempool)
/// [BIP35]: https://github.com/bitcoin/bips/blob/master/bip-0035.mediawiki
Mempool {/* XXX add fields */},
/// A `filterload` message.
///
/// This was defined in [BIP37], which is included in Zcash.
///
/// [Bitcoin reference](https://en.bitcoin.it/wiki/Protocol_documentation#filterload.2C_filteradd.2C_filterclear.2C_merkleblock)
/// [BIP37]: https://github.com/bitcoin/bips/blob/master/bip-0037.mediawiki
FilterLoad {/* XXX add fields */},
/// A `filteradd` message.
///
/// This was defined in [BIP37], which is included in Zcash.
///
/// [Bitcoin reference](https://en.bitcoin.it/wiki/Protocol_documentation#filterload.2C_filteradd.2C_filterclear.2C_merkleblock)
/// [BIP37]: https://github.com/bitcoin/bips/blob/master/bip-0037.mediawiki
FilterAdd {/* XXX add fields */},
/// A `filterclear` message.
///
/// This was defined in [BIP37], which is included in Zcash.
///
/// [Bitcoin reference](https://en.bitcoin.it/wiki/Protocol_documentation#filterload.2C_filteradd.2C_filterclear.2C_merkleblock)
/// [BIP37]: https://github.com/bitcoin/bips/blob/master/bip-0037.mediawiki
FilterClear {/* XXX add fields */},
/// A `merkleblock` message.
///
/// This was defined in [BIP37], which is included in Zcash.
///
/// [Bitcoin reference](https://en.bitcoin.it/wiki/Protocol_documentation#filterload.2C_filteradd.2C_filterclear.2C_merkleblock)
/// [BIP37]: https://github.com/bitcoin/bips/blob/master/bip-0037.mediawiki
MerkleBlock {/* XXX add fields */},
}
/// Reject Reason CCodes
///
/// [Bitcoin reference](https://en.bitcoin.it/wiki/Protocol_documentation#reject)
#[derive(Copy, Clone, Debug, Eq, PartialEq)]
#[repr(u8)]
#[allow(missing_docs)]
pub enum RejectReason {
Malformed = 0x01,
Invalid = 0x10,
Obsolete = 0x11,
Duplicate = 0x12,
Nonstandard = 0x40,
Dust = 0x41,
InsufficientFee = 0x42,
Checkpoint = 0x43,
}
// Q: how do we want to implement serialization, exactly? do we want to have
// something generic over stdlib Read and Write traits, or over async versions
// of those traits?
//
// Note: because of the way the message structure is defined (checksum comes
// first) we can't write the message headers before collecting the whole body
// into a buffer
//
// Maybe just write some functions and refactor later?
impl Message {
/// Send `self` to the given async writer (e.g., a network stream).
pub async fn send<W: Unpin + AsyncWrite>(
&self,
mut writer: W,
magic: Magic,
version: Version,
) -> Result<(), SerializationError> {
// Because the header contains a checksum of
// the body data, it must be written first.
let mut body = Vec::new();
self.write_body(&mut body, magic, version)?;
use Message::*;
// Note: because all match arms must have
// the same type, and the array length is
// part of the type, having at least one
// of length 12 checks that they are all
// of length 12, as they must be &[u8; 12].
let command = match *self {
Version { .. } => b"version\0\0\0\0\0",
Verack { .. } => b"verack\0\0\0\0\0\0",
Ping { .. } => b"ping\0\0\0\0\0\0\0\0",
Pong { .. } => b"pong\0\0\0\0\0\0\0\0",
Reject { .. } => b"reject\0\0\0\0\0\0",
Addr { .. } => b"addr\0\0\0\0\0\0\0\0",
GetAddr { .. } => b"getaddr\0\0\0\0\0",
Block { .. } => b"block\0\0\0\0\0\0\0",
GetBlocks { .. } => b"getblocks\0\0\0",
Headers { .. } => b"headers\0\0\0\0\0",
GetHeaders { .. } => b"getheaders\0\0",
Inventory { .. } => b"inv\0\0\0\0\0\0\0\0\0",
GetData { .. } => b"getdata\0\0\0\0\0",
NotFound { .. } => b"notfound\0\0\0\0",
Tx { .. } => b"tx\0\0\0\0\0\0\0\0\0\0",
Mempool { .. } => b"mempool\0\0\0\0\0",
FilterLoad { .. } => b"filterload\0\0",
FilterAdd { .. } => b"filteradd\0\0\0",
FilterClear { .. } => b"filterclear\0",
MerkleBlock { .. } => b"merkleblock\0",
};
// Write the header into a stack buffer first before feeding that stack
// buffer into the async writer. This allows using the WriteBytesExt
// extension trait, which is only defined for sync Writers.
// The header is 4+12+4+4=24 bytes long.
let mut header = [0u8; 24];
let mut header_writer = Cursor::new(&mut header[..]);
header_writer.write_all(&magic.0)?;
header_writer.write_all(command)?;
header_writer.write_u32::<LittleEndian>(body.len() as u32)?;
header_writer.write_all(&Sha256dChecksum::from(&body[..]).0)?;
writer.write_all(&header).await?;
writer.write_all(&body).await?;
Ok(())
}
/// Receive a message from the given async reader (e.g., a network stream).
pub async fn recv<R: Unpin + AsyncRead>(
mut reader: R,
magic: Magic,
version: Version,
) -> Result<Self, SerializationError> {
use SerializationError::ParseError;
// Read the header into a stack buffer before trying to parse it. This
// allows using the ReadBytesExt extension trait, which is only defined
// for sync Readers. Then we can determine the expected message length,
// await that many bytes, and finally parse the message.
// The header is 4+12+4+4=24 bytes long.
let header = {
let mut bytes = [0u8; 24];
reader.read_exact(&mut bytes).await?;
bytes
};
let mut header_reader = Cursor::new(&header[..]);
// Read header data
let message_magic = Magic(header_reader.read_4_bytes()?);
let command = header_reader.read_12_bytes()?;
let body_len = header_reader.read_u32::<LittleEndian>()? as usize;
let checksum = Sha256dChecksum(header_reader.read_4_bytes()?);
if magic != message_magic {
return Err(ParseError("Message has incorrect magic value"));
}
// XXX bound the body_len value to avoid large attacker-controlled allocs
// XXX add a ChecksumReader<R: Read>(R) wrapper and avoid this
let body = {
let mut bytes = vec![0; body_len];
reader.read_exact(&mut bytes).await?;
bytes
};
if checksum != Sha256dChecksum::from(&body[..]) {
return Err(SerializationError::ParseError("checksum does not match"));
}
let body_reader = Cursor::new(&body);
match &command {
b"version\0\0\0\0\0" => try_read_version(body_reader, version),
b"verack\0\0\0\0\0\0" => try_read_verack(body_reader, version),
b"ping\0\0\0\0\0\0\0\0" => try_read_ping(body_reader, version),
b"pong\0\0\0\0\0\0\0\0" => try_read_pong(body_reader, version),
b"reject\0\0\0\0\0\0" => try_read_reject(body_reader, version),
b"addr\0\0\0\0\0\0\0\0" => try_read_addr(body_reader, version),
b"getaddr\0\0\0\0\0" => try_read_getaddr(body_reader, version),
b"block\0\0\0\0\0\0\0" => try_read_block(body_reader, version),
b"getblocks\0\0\0" => try_read_getblocks(body_reader, version),
b"headers\0\0\0\0\0" => try_read_headers(body_reader, version),
b"getheaders\0\0" => try_read_getheaders(body_reader, version),
b"inv\0\0\0\0\0\0\0\0\0" => try_read_inv(body_reader, version),
b"getdata\0\0\0\0\0" => try_read_getdata(body_reader, version),
b"notfound\0\0\0\0" => try_read_notfound(body_reader, version),
b"tx\0\0\0\0\0\0\0\0\0\0" => try_read_tx(body_reader, version),
b"mempool\0\0\0\0\0" => try_read_mempool(body_reader, version),
b"filterload\0\0" => try_read_filterload(body_reader, version),
b"filteradd\0\0\0" => try_read_filteradd(body_reader, version),
b"filterclear\0" => try_read_filterclear(body_reader, version),
b"merkleblock\0" => try_read_merkleblock(body_reader, version),
_ => Err(ParseError("Unknown command")),
}
}
}
impl Message {
/// Write the body of the message into the given writer. This allows writing
/// the message body prior to writing the header, so that the header can
/// contain a checksum of the message body.
fn write_body<W: io::Write>(
&self,
mut writer: W,
_m: Magic,
_v: Version,
) -> Result<(), SerializationError> {
use Message::*;
match *self {
Version {
ref version,
ref services,
ref timestamp,
ref address_recv,
ref address_from,
ref nonce,
ref user_agent,
ref start_height,
ref relay,
} => {
writer.write_u32::<LittleEndian>(version.0)?;
writer.write_u64::<LittleEndian>(services.0)?;
writer.write_i64::<LittleEndian>(timestamp.timestamp())?;
let (recv_services, recv_addr) = address_recv;
writer.write_u64::<LittleEndian>(recv_services.0)?;
writer.write_socket_addr(*recv_addr)?;
let (from_services, from_addr) = address_from;
writer.write_u64::<LittleEndian>(from_services.0)?;
writer.write_socket_addr(*from_addr)?;
writer.write_u64::<LittleEndian>(nonce.0)?;
writer.write_string(&user_agent)?;
writer.write_u32::<LittleEndian>(start_height.0)?;
writer.write_u8(*relay as u8)?;
}
Verack => { /* Empty payload -- no-op */ }
Ping(nonce) => {
writer.write_u64::<LittleEndian>(nonce.0)?;
}
Pong(nonce) => {
writer.write_u64::<LittleEndian>(nonce.0)?;
}
_ => unimplemented!(),
}
Ok(())
}
}
fn try_read_version<R: io::Read>(
mut reader: R,
_parsing_version: Version,
) -> Result<Message, SerializationError> {
Ok(Message::Version {
version: Version(reader.read_u32::<LittleEndian>()?),
services: Services(reader.read_u64::<LittleEndian>()?),
timestamp: Utc.timestamp(reader.read_i64::<LittleEndian>()?, 0),
address_recv: (
Services(reader.read_u64::<LittleEndian>()?),
reader.read_socket_addr()?,
),
address_from: (
Services(reader.read_u64::<LittleEndian>()?),
reader.read_socket_addr()?,
),
nonce: Nonce(reader.read_u64::<LittleEndian>()?),
user_agent: reader.read_string()?,
start_height: BlockHeight(reader.read_u32::<LittleEndian>()?),
relay: match reader.read_u8()? {
0 => false,
1 => true,
_ => return Err(SerializationError::ParseError("non-bool value")),
},
})
}
fn try_read_verack<R: io::Read>(
mut _reader: R,
_version: Version,
) -> Result<Message, SerializationError> {
Ok(Message::Verack)
}
fn try_read_ping<R: io::Read>(
mut reader: R,
_version: Version,
) -> Result<Message, SerializationError> {
Ok(Message::Ping(Nonce(reader.read_u64::<LittleEndian>()?)))
}
fn try_read_pong<R: io::Read>(
mut reader: R,
_version: Version,
) -> Result<Message, SerializationError> {
Ok(Message::Pong(Nonce(reader.read_u64::<LittleEndian>()?)))
}
fn try_read_reject<R: io::Read>(
mut _reader: R,
_version: Version,
) -> Result<Message, SerializationError> {
unimplemented!()
}
fn try_read_addr<R: io::Read>(
mut _reader: R,
_version: Version,
) -> Result<Message, SerializationError> {
unimplemented!()
}
fn try_read_getaddr<R: io::Read>(
mut _reader: R,
_version: Version,
) -> Result<Message, SerializationError> {
unimplemented!()
}
fn try_read_block<R: io::Read>(
mut _reader: R,
_version: Version,
) -> Result<Message, SerializationError> {
unimplemented!()
}
fn try_read_getblocks<R: io::Read>(
mut _reader: R,
_version: Version,
) -> Result<Message, SerializationError> {
unimplemented!()
}
fn try_read_headers<R: io::Read>(
mut _reader: R,
_version: Version,
) -> Result<Message, SerializationError> {
unimplemented!()
}
fn try_read_getheaders<R: io::Read>(
mut _reader: R,
_version: Version,
) -> Result<Message, SerializationError> {
unimplemented!()
}
fn try_read_inv<R: io::Read>(
mut _reader: R,
_version: Version,
) -> Result<Message, SerializationError> {
unimplemented!()
}
fn try_read_getdata<R: io::Read>(
mut _reader: R,
_version: Version,
) -> Result<Message, SerializationError> {
unimplemented!()
}
fn try_read_notfound<R: io::Read>(
mut _reader: R,
_version: Version,
) -> Result<Message, SerializationError> {
unimplemented!()
}
fn try_read_tx<R: io::Read>(
mut _reader: R,
_version: Version,
) -> Result<Message, SerializationError> {
unimplemented!()
}
fn try_read_mempool<R: io::Read>(
mut _reader: R,
_version: Version,
) -> Result<Message, SerializationError> {
unimplemented!()
}
fn try_read_filterload<R: io::Read>(
mut _reader: R,
_version: Version,
) -> Result<Message, SerializationError> {
unimplemented!()
}
fn try_read_filteradd<R: io::Read>(
mut _reader: R,
_version: Version,
) -> Result<Message, SerializationError> {
unimplemented!()
}
fn try_read_filterclear<R: io::Read>(
mut _reader: R,
_version: Version,
) -> Result<Message, SerializationError> {
unimplemented!()
}
fn try_read_merkleblock<R: io::Read>(
mut _reader: R,
_version: Version,
) -> Result<Message, SerializationError> {
unimplemented!()
}
#[cfg(test)]
mod tests {
use super::*;
use tokio::runtime::Runtime;
#[test]
fn version_message_round_trip() {
use std::net::{IpAddr, Ipv4Addr, SocketAddr};
let services = Services(0x1);
let timestamp = Utc.timestamp(1568000000, 0);
let rt = Runtime::new().unwrap();
let v = Message::Version {
version: crate::constants::CURRENT_VERSION,
services,
timestamp,
address_recv: (
services,
SocketAddr::new(IpAddr::V4(Ipv4Addr::new(203, 0, 113, 6)), 8233),
),
address_from: (
services,
SocketAddr::new(IpAddr::V4(Ipv4Addr::new(203, 0, 113, 6)), 8233),
),
nonce: Nonce(0x9082_4908_8927_9238),
user_agent: "Zebra".to_owned(),
start_height: BlockHeight(540_000),
relay: true,
};
let v_bytes = rt.block_on(async {
let mut bytes = Vec::new();
v.send(
&mut bytes,
crate::constants::magics::MAINNET,
crate::constants::CURRENT_VERSION,
)
.await
.unwrap();
bytes
});
let v_parsed = rt.block_on(async {
Message::recv(
Cursor::new(&v_bytes),
crate::constants::magics::MAINNET,
crate::constants::CURRENT_VERSION,
)
.await
.unwrap()
});
assert_eq!(v, v_parsed);
}
}
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