Add EIP 7636 support (#81)

Co-authored-by: Age Manning <Age@AgeManning.com>

src/builder.rs

@@ -110,6 +110,22 @@ impl<K: EnrKey> Builder<K> {
         self
     }
 
+    /// Adds a [EIP-7636](https://eips.ethereum.org/EIPS/eip-7636) `client` field to the `ENRBuilder`.
+    pub fn client_info(
+        &mut self,
+        name: String,
+        version: String,
+        build: Option<String>,
+    ) -> &mut Self {
+        if build.is_none() {
+            self.add_value("client", &vec![name, version]);
+        } else {
+            self.add_value("client", &vec![name, version, build.unwrap()]);
+        }
+
+        self
+    }
+
     /// Generates the rlp-encoded form of the ENR specified by the builder config.
     fn rlp_content(&self) -> BytesMut {
         let mut list = Vec::<u8>::with_capacity(MAX_ENR_SIZE);

src/lib.rs

@@ -343,6 +343,36 @@ impl<K: EnrKey> Enr<K> {
         None
     }
 
+    /// Returns [EIP-7636](https://eips.ethereum.org/EIPS/eip-7636) entry if it is defined.
+    #[must_use]
+    pub fn client_info(&self) -> Option<(String, String, Option<String>)> {
+        if let Some(Ok(client_list)) = self.get_decodable::<Vec<Bytes>>("client") {
+            match client_list.len() {
+                2 => {
+                    let client_name = String::from_utf8_lossy(client_list[0].as_ref()).to_string();
+
+                    let client_version =
+                        String::from_utf8_lossy(client_list[1].as_ref()).to_string();
+
+                    return Some((client_name, client_version, None));
+                }
+                3 => {
+                    let client_name = String::from_utf8_lossy(client_list[0].as_ref()).to_string();
+
+                    let client_version =
+                        String::from_utf8_lossy(client_list[1].as_ref()).to_string();
+
+                    let client_additional =
+                        String::from_utf8_lossy(client_list[2].as_ref()).to_string();
+                    return Some((client_name, client_version, Some(client_additional)));
+                }
+                _ => {}
+            }
+        }
+
+        None
+    }
+
     /// The TCP port of ENR record if it is defined.
     #[must_use]
     pub fn tcp4(&self) -> Option<u16> {
@@ -620,6 +650,23 @@ impl<K: EnrKey> Enr<K> {
         Ok(None)
     }
 
+    /// Sets the [EIP-7636](https://eips.ethereum.org/EIPS/eip-7636) `client` field in the record.
+    pub fn set_client_info(
+        &mut self,
+        name: String,
+        version: String,
+        build: Option<String>,
+        key: &K,
+    ) -> Result<(), Error> {
+        if build.is_none() {
+            self.insert("client", &vec![name, version], key)?;
+        } else {
+            self.insert("client", &vec![name, version, build.unwrap()], key)?;
+        }
+
+        Ok(())
+    }
+
     /// Sets the IP and UDP port in a single update with a single increment in sequence number.
     pub fn set_udp_socket(&mut self, socket: SocketAddr, key: &K) -> Result<(), Error> {
         self.set_socket(socket, key, false)
@@ -1969,6 +2016,79 @@ mod tests {
         assert_eq!(record.seq(), 30);
     }
 
+    #[test]
+    fn test_set_client_eip7636() {
+        let key = k256::ecdsa::SigningKey::random(&mut rand::thread_rng());
+        let mut enr = Enr::empty(&key).unwrap();
+
+        enr.set_client_info(
+            "Test".to_string(),
+            "v1.0.0".to_string(),
+            Some("Test".to_string()),
+            &key,
+        )
+        .unwrap();
+        assert!(enr.verify());
+
+        enr.set_client_info("Test".to_string(), "v1.0.0".to_string(), None, &key)
+            .unwrap();
+        assert!(enr.verify());
+    }
+
+    #[test]
+    fn test_get_eip7636() {
+        let example_eip = "enr:-MO4QBn4OF-y-dqULg4WOIlc8gQAt-arldNFe0_YQ4HNX28jDtg41xjDyKfCXGfZaPN97I-MCfogeK91TyqmWTpb0_AChmNsaWVudNqKTmV0aGVybWluZIYxLjkuNTOHN2ZjYjU2N4JpZIJ2NIJpcIR_AAABg2lwNpAAAAAAAAAAAAAAAAAAAAABiXNlY3AyNTZrMaECn-TTdCwfZP4XgJyq8Lxoj-SgEoIFgDLVBEUqQk4HnAqDdWRwgiMshHVkcDaCIyw";
+        let enr = example_eip.parse::<DefaultEnr>().unwrap();
+
+        let info = enr.client_info().unwrap();
+
+        assert_eq!(info.0, "Nethermind");
+        assert_eq!(info.1, "1.9.53");
+        assert_eq!(info.2.unwrap(), "7fcb567");
+
+        let key = k256::ecdsa::SigningKey::random(&mut rand::thread_rng());
+        let mut enr = Enr::empty(&key).unwrap();
+
+        enr.set_client_info("Test".to_string(), "v1.0.0".to_string(), None, &key)
+            .unwrap();
+
+        let info = enr.client_info().unwrap();
+        assert_eq!(info.0, "Test");
+        assert_eq!(info.1, "v1.0.0");
+        assert_eq!(info.2, None);
+    }
+
+    #[test]
+    fn test_builder_eip7636() {
+        let key = k256::ecdsa::SigningKey::random(&mut rand::thread_rng());
+        let enr = Enr::builder()
+            .ip4(Ipv4Addr::new(127, 0, 0, 1))
+            .tcp4(30303)
+            .client_info(
+                "Test".to_string(),
+                "v1.0.0".to_string(),
+                Some("Test".to_string()),
+            )
+            .build(&key)
+            .unwrap();
+
+        let info = enr.client_info().unwrap();
+        assert_eq!(info.0, "Test");
+        assert_eq!(info.1, "v1.0.0");
+        assert_eq!(info.2.unwrap(), "Test");
+
+        let enr = Enr::builder()
+            .ip4(Ipv4Addr::new(127, 0, 0, 1))
+            .tcp4(30303)
+            .client_info("Test".to_string(), "v1.0.0".to_string(), None)
+            .build(&key)
+            .unwrap();
+
+        let info = enr.client_info().unwrap();
+        assert_eq!(info.0, "Test");
+        assert_eq!(info.1, "v1.0.0");
+        assert_eq!(info.2, None);
+    }
     /// Tests a common ENR which uses RLP encoded values without the header
     #[test]
     fn test_common_rlp_convention() {