324 lines
12 KiB
Rust
324 lines
12 KiB
Rust
//! Definitions of network messages.
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use std::io;
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use chrono::{DateTime, Utc};
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use zebra_chain::types::Sha256dChecksum;
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use crate::meta_addr::MetaAddr;
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use crate::types::*;
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/// A Bitcoin-like network message for the Zcash protocol.
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///
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/// The Zcash network protocol is mostly inherited from Bitcoin, and a list of
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/// Bitcoin network messages can be found [on the Bitcoin
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/// wiki][btc_wiki_protocol].
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///
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/// That page describes the wire format of the messages, while this enum stores
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/// an internal representation. The internal representation is unlinked from the
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/// wire format, and the translation between the two happens only during
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/// serialization and deserialization. For instance, Bitcoin identifies messages
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/// by a 12-byte ascii command string; we consider this a serialization detail
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/// and use the enum discriminant instead. (As a side benefit, this also means
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/// that we have a clearly-defined validation boundary for network messages
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/// during serialization).
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///
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/// [btc_wiki_protocol]: https://en.bitcoin.it/wiki/Protocol_documentation
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//
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// XXX not all messages are filled in yet. Messages written as { /* XXX add
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// fields */ } are explicitly incomplete and we need to define a mapping between
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// the serialized message data and the internal representation. Note that this
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// is different from messages like GetAddr which have no data (and so have no
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// fields).
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pub enum Message {
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/// A `version` message.
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///
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/// Note that although this is called `version` in Bitcoin, its role is really
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/// analogous to a `ClientHello` message in TLS, used to begin a handshake, and
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/// is distinct from a simple version number.
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///
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/// [Bitcoin reference](https://en.bitcoin.it/wiki/Protocol_documentation#version)
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Version {
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/// The network version number supported by the sender.
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version: Version,
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/// The network services advertised by the sender.
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services: Services,
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/// The time when the version message was sent.
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timestamp: DateTime<Utc>,
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/// The network address of the node receiving this message.
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///
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/// Note that the timestamp field of the [`MetaAddr`] is not included in
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/// the serialization of `version` messages.
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address_receiving: MetaAddr,
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/// The network address of the node emitting this message.
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///
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/// Note that the timestamp field of the [`MetaAddr`] is not included in
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/// the serialization of `version` messages.
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address_from: MetaAddr,
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/// Node random nonce, randomly generated every time a version
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/// packet is sent. This nonce is used to detect connections
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/// to self.
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nonce: Nonce,
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/// The Zcash user agent advertised by the sender.
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user_agent: String,
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/// The last block received by the emitting node.
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start_height: zebra_chain::types::BlockHeight,
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/// Whether the remote peer should announce relayed
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/// transactions or not, see [BIP 0037](https://github.com/bitcoin/bips/blob/master/bip-0037.mediawiki)
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relay: bool,
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},
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/// A `verack` message.
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///
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/// [Bitcoin reference](https://en.bitcoin.it/wiki/Protocol_documentation#verack)
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Verack,
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/// A `ping` message.
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///
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/// [Bitcoin reference](https://en.bitcoin.it/wiki/Protocol_documentation#ping)
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Ping(Nonce),
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/// A `pong` message.
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///
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/// [Bitcoin reference](https://en.bitcoin.it/wiki/Protocol_documentation#pong)
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Pong(
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/// The nonce from the `Ping` message this was in response to.
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Nonce,
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),
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/// A `reject` message.
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///
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/// [Bitcoin reference](https://en.bitcoin.it/wiki/Protocol_documentation#reject)
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Reject {
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/// Type of message rejected.
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// Q: can we just reference the Type, rather than instantiate an instance of the enum type?
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message: Box<Message>,
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/// RejectReason code relating to rejected message.
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ccode: RejectReason,
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/// Human-readable version of rejection reason.
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reason: String,
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/// Optional extra data provided for some errors.
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// Currently, all errors which provide this field fill it with
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// the TXID or block header hash of the object being rejected,
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// so the field is 32 bytes.
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//
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// Q: can we tell Rust that this field is optional? Or just
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// default its value to an empty array, I guess.
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data: [u8; 32],
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},
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/// An `addr` message.
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///
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/// [Bitcoin reference](https://en.bitcoin.it/wiki/Protocol_documentation#addr)
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Addr(Vec<MetaAddr>),
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/// A `getaddr` message.
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///
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/// [Bitcoin reference](https://en.bitcoin.it/wiki/Protocol_documentation#getaddr)
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GetAddr,
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/// A `block` message.
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///
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/// [Bitcoin reference](https://en.bitcoin.it/wiki/Protocol_documentation#block)
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Block {/* XXX add fields */},
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/// A `getblocks` message.
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///
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/// [Bitcoin reference](https://en.bitcoin.it/wiki/Protocol_documentation#getblocks)
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GetBlocks {/* XXX add fields */},
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/// A `headers` message.
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///
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/// [Bitcoin reference](https://en.bitcoin.it/wiki/Protocol_documentation#headers)
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Headers {/* XXX add fields */},
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/// A `getheaders` message.
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///
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/// [Bitcoin reference](https://en.bitcoin.it/wiki/Protocol_documentation#getheaders)
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GetHeaders {/* XXX add fields */},
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/// An `inv` message.
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///
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/// [Bitcoin reference](https://en.bitcoin.it/wiki/Protocol_documentation#inv)
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// XXX the bitcoin reference above suggests this can be 1.8 MB in bitcoin -- maybe
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// larger in Zcash, since Zcash objects could be bigger (?) -- does this tilt towards
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// having serialization be async?
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Inventory {
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/// Number of inventory entries.
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count: u64,
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/// Inventory vectors.
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inventory: Vec<zebra_chain::types::InventoryVector>,
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},
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/// A `getdata` message.
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///
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/// `getdata` is used in response to `inv`, to retrieve the content of
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/// a specific object, and is usually sent after receiving an `inv`
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/// packet, after filtering known elements.
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///
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/// [Bitcoin reference](https://en.bitcoin.it/wiki/Protocol_documentation#getdata)
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GetData {
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/// Number of inventory entries.
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count: u64,
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/// Inventory vectors.
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inventory: Vec<zebra_chain::types::InventoryVector>,
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},
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/// A `notfound` message.
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///
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/// [Bitcoin reference](https://en.bitcoin.it/wiki/Protocol_documentation#notfound)
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// See note above on `Inventory`.
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NotFound {
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/// Number of inventory entries.
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count: u64,
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/// Inventory vectors.
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inventory: Vec<zebra_chain::types::InventoryVector>,
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},
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/// A `tx` message.
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///
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/// [Bitcoin reference](https://en.bitcoin.it/wiki/Protocol_documentation#tx)
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Tx {/* XXX add fields */},
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/// A `mempool` message.
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///
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/// This was defined in [BIP35], which is included in Zcash.
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///
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/// [Bitcoin reference](https://en.bitcoin.it/wiki/Protocol_documentation#mempool)
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/// [BIP35]: https://github.com/bitcoin/bips/blob/master/bip-0035.mediawiki
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Mempool {/* XXX add fields */},
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/// A `filterload` message.
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///
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/// This was defined in [BIP37], which is included in Zcash.
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///
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/// [Bitcoin reference](https://en.bitcoin.it/wiki/Protocol_documentation#filterload.2C_filteradd.2C_filterclear.2C_merkleblock)
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/// [BIP37]: https://github.com/bitcoin/bips/blob/master/bip-0037.mediawiki
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FilterLoad {/* XXX add fields */},
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/// A `filteradd` message.
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///
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/// This was defined in [BIP37], which is included in Zcash.
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///
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/// [Bitcoin reference](https://en.bitcoin.it/wiki/Protocol_documentation#filterload.2C_filteradd.2C_filterclear.2C_merkleblock)
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/// [BIP37]: https://github.com/bitcoin/bips/blob/master/bip-0037.mediawiki
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FilterAdd {/* XXX add fields */},
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/// A `filterclear` message.
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///
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/// This was defined in [BIP37], which is included in Zcash.
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///
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/// [Bitcoin reference](https://en.bitcoin.it/wiki/Protocol_documentation#filterload.2C_filteradd.2C_filterclear.2C_merkleblock)
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/// [BIP37]: https://github.com/bitcoin/bips/blob/master/bip-0037.mediawiki
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FilterClear {/* XXX add fields */},
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/// A `merkleblock` message.
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///
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/// This was defined in [BIP37], which is included in Zcash.
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///
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/// [Bitcoin reference](https://en.bitcoin.it/wiki/Protocol_documentation#filterload.2C_filteradd.2C_filterclear.2C_merkleblock)
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/// [BIP37]: https://github.com/bitcoin/bips/blob/master/bip-0037.mediawiki
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MerkleBlock {/* XXX add fields */},
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}
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/// Reject Reason CCodes
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///
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/// [Bitcoin reference](https://en.bitcoin.it/wiki/Protocol_documentation#reject)
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#[repr(u8)]
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#[allow(missing_docs)]
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pub enum RejectReason {
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Malformed = 0x01,
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Invalid = 0x10,
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Obsolete = 0x11,
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Duplicate = 0x12,
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Nonstandard = 0x40,
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Dust = 0x41,
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InsufficientFee = 0x42,
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Checkpoint = 0x43,
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}
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// Q: how do we want to implement serialization, exactly? do we want to have
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// something generic over stdlib Read and Write traits, or over async versions
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// of those traits?
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//
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// Note: because of the way the message structure is defined (checksum comes
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// first) we can't write the message headers before collecting the whole body
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// into a buffer
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//
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// Maybe just write some functions and refactor later?
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impl Message {
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/// Serialize `self` into the given writer.
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pub fn write<W: io::Write>(&self, mut writer: W, magic: Magic) -> io::Result<()> {
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use byteorder::{LittleEndian, WriteBytesExt};
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// Because the header contains a checksum of
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// the body data, it must be written first.
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let mut body = Vec::new();
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self.write_body(&mut body)?;
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use Message::*;
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// Note: because all match arms must have
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// the same type, and the array length is
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// part of the type, having at least one
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// of length 12 checks that they are all
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// of length 12, as they must be &[u8; 12].
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let command = match *self {
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Version { .. } => b"version\0\0\0\0\0",
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Verack { .. } => b"verack\0\0\0\0\0\0",
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Ping { .. } => b"ping\0\0\0\0\0\0\0\0",
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Pong { .. } => b"pong\0\0\0\0\0\0\0\0",
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Reject { .. } => b"reject\0\0\0\0\0\0",
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Addr { .. } => b"addr\0\0\0\0\0\0\0\0",
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GetAddr { .. } => b"getaddr\0\0\0\0\0",
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Block { .. } => b"block\0\0\0\0\0\0\0",
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GetBlocks { .. } => b"getblocks\0\0\0",
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Headers { .. } => b"headers\0\0\0\0\0",
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GetHeaders { .. } => b"getheaders\0\0",
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Inventory { .. } => b"inv\0\0\0\0\0\0\0\0\0",
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GetData { .. } => b"getdata\0\0\0\0\0",
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NotFound { .. } => b"notfound\0\0\0\0",
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Tx { .. } => b"tx\0\0\0\0\0\0\0\0\0\0",
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Mempool { .. } => b"mempool\0\0\0\0\0",
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FilterLoad { .. } => b"filterload\0\0",
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FilterAdd { .. } => b"filteradd\0\0\0",
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FilterClear { .. } => b"filterclear\0",
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MerkleBlock { .. } => b"merkleblock\0",
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};
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// Write the header and then the body.
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writer.write_u32::<LittleEndian>(magic.0)?;
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writer.write_all(command)?;
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writer.write_u32::<LittleEndian>(body.len() as u32)?;
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writer.write_all(&Sha256dChecksum::from(&body[..]).0)?;
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writer.write_all(&body)
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}
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/// Write the body of the message into the given writer. This allows writing
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/// the message body prior to writing the header, so that the header can
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/// contain a checksum of the message body.
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fn write_body<W: io::Write>(&self, _writer: W) -> io::Result<()> {
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unimplemented!()
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}
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/// Try to deserialize a [`Message`] from the given reader.
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pub fn try_read<R: io::Read>(_reader: R) -> Result<Self, String> {
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unimplemented!()
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}
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}
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