enr-cli 0.7.1

Simple utility to read Ethereum Node Records (ENR)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40

use crate::Enr;
use bytes::Bytes;
use ssz::Decode;
use ssz_derive::{Decode, Encode};

/// The ENR field specifying the fork id.
pub const ETH2_ENR_KEY: &str = "eth2";
/// The ENR field specifying the subnet bitfield.
pub const BITFIELD_ENR_KEY: &str = "attnets";

#[derive(Debug, Clone, PartialEq, Default, Encode, Decode, Eq)]
pub struct EnrForkId {
    pub fork_digest: [u8; 4],
    pub next_fork_version: [u8; 4],
    pub next_fork_epoch: u64,
}

/// Extension trait for ENR's within Eth2.
pub trait Eth2Enr {
    /// The subnet bitfield associated with the ENR.
    fn bitfield(&self) -> Option<Vec<u8>>;
    fn eth2(&self) -> Result<EnrForkId, &'static str>;
}

impl Eth2Enr for Enr {
    fn bitfield(&self) -> Option<Vec<u8>> {
        self.get_decodable(BITFIELD_ENR_KEY)?
            .ok()
            .map(|v: Bytes| v.to_vec())
    }

    fn eth2(&self) -> Result<EnrForkId, &'static str> {
        let eth2_bytes = self
            .get_decodable::<Bytes>(ETH2_ENR_KEY)
            .ok_or("ENR has no eth2 field")?
            .map_err(|_| "Could not decode fork id")?;

        EnrForkId::from_ssz_bytes(&eth2_bytes).map_err(|_| "Could not decode EnrForkId")
    }
}