p2p: add V1MessageHeader encoding traits
What the developer wrote
Authored by yancy
p2p: add V1MessageHeader encoding traits
`V1MessageHeader` has traits for decoding a message header, however the
traits to encode a header are missing.
The four fields that are encoded are as follows:
* magic.encoder()
* command.encoder()
* length is cast using to_le_bytes per protocol docs
* no casting is needed for checksum since it's already a u8[]
ref: https://en.bitcoin.it/wiki/Protocol_documentation
What changed, and why it matters
This commit adds the missing ability to encode (serialize) Bitcoin P2P v1 message headers, matching the existing decoding support. It is a straightforward feature addition with no security-relevant behavior change.
No security action required. Review as normal code-quality/feature completeness change.
Security signals we found
No strong security signals were identified.
Evidence from the diff
The patch implements Encodable for V1MessageHeader in p2p/src/message.rs, producing a 24-byte header (4-byte magic, 12-byte command, 4-byte little-endian payload length, 4-byte checksum). It uses the project’s existing encoder combinators and matches the protocol documentation. No logic is modified or removed; only serialization traits are added.
Changed components
p2p/src/message.rsV1MessageHeaderInspect captured patch +30 / −0
diff --git a/p2p/src/message.rs b/p2p/src/message.rs
index 59fd0db2..2a1d0a69 100644
--- a/p2p/src/message.rs
+++ b/p2p/src/message.rs
@@ -285,6 +285,36 @@ pub struct V1MessageHeader {
pub checksum: [u8; 4],
}
+impl encoding::Encodable for V1MessageHeader {
+ type Encoder<'e>
+ = V1MessageHeaderEncoder<'e>
+ where
+ Self: 'e;
+
+ #[inline]
+ fn encoder(&self) -> Self::Encoder<'_> {
+ let enc = encoding::Encoder4::new(
+ self.magic.encoder(),
+ self.command.encoder(),
+ encoding::ArrayEncoder::without_length_prefix(self.length.to_le_bytes()),
+ encoding::ArrayEncoder::without_length_prefix(self.checksum),
+ );
+
+ V1MessageHeaderEncoder::new(enc)
+ }
+}
+
+encoding::encoder_newtype! {
+ /// The encoder for the [`V1MessageHeader`] type.
+ pub struct V1MessageHeaderEncoder<'e>(
+ encoding::Encoder4<
+ crate::MagicEncoder<'e>,
+ CommandStringEncoder,
+ encoding::ArrayEncoder<4>,
+ encoding::ArrayEncoder<4>
+ >);
+}
+
type V1MessageHeaderInnerDecoder = encoding::Decoder4<
encoding::ArrayDecoder<4>,
CommandStringDecoder,
Why this scored 15/100
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