Use lazy_static to evaluate the chain config

This is to make messages network-agnostic and keep the interface
of each message clean as they don't really care what network is in
use when they are being created.

Saving the chain config to a lazily evaluated static variable allows
the chain config data to be specified at the start-up but also allows
different subsystems to use the values as if they were static variables.

Author: altonen

common/Cargo.toml

@@ -7,6 +7,7 @@ license = "MIT"
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
 [dependencies]
+lazy_static = "1.4.0"
 fixed-hash = { version = "0.7.0", default-features = true, features = ["std"] }
 bech32 = "0.8.1"
 thiserror = "1.0.30"

common/src/chain/config.rs

@@ -26,7 +26,7 @@ pub struct ChainConfig {
     #[allow(dead_code)]
     height_checkpoint_data: BTreeMap<BlockHeight, HashType>,
     #[allow(dead_code)]
-    magic_bytes: [u8; 4],
+    pub magic_bytes: [u8; 4],
 }
 
 impl ChainConfig {
@@ -35,6 +35,10 @@ impl ChainConfig {
     }
 }
 
+lazy_static::lazy_static! {
+    pub static ref CHAIN_CONFIG: ChainConfig = create_mainnet();
+}
+
 #[allow(dead_code)]
 pub fn create_mainnet() -> ChainConfig {
     ChainConfig {

p2p/src/message.rs

@@ -14,7 +14,7 @@
 // limitations under the License.
 //
 // Author(s): A. Altonen
-use common::chain::config::{ChainType, MAGIC_BYTES};
+use common::chain::config::CHAIN_CONFIG;
 use parity_scale_codec::{Decode, Encode};
 use util::Message;
 
@@ -40,8 +40,6 @@ pub struct Message {
 pub struct Hello {
     /// Version of the software
     version: u32,
-    /// Network ID
-    network: ChainType,
     /// Services provided by the node
     services: u32,
     /// Unix timestamp
@@ -52,8 +50,6 @@ pub struct Hello {
 pub struct HelloAck {
     /// Version of the software
     version: u32,
-    /// Network ID
-    network: ChainType,
     /// Services provided by the node
     services: u32,
     /// Unix timestamp
@@ -73,7 +69,7 @@ mod tests {
         let timestamp: u64 =
             SystemTime::now().duration_since(SystemTime::UNIX_EPOCH).unwrap().as_secs();
 
-        let hello = Hello::new(version, ChainType::Mainnet, services, timestamp);
+        let hello = Hello::new(version, services, timestamp);
         let msg: Message = hello.clone().into();
 
         // Hello message cannot be converted to HelloAck message
@@ -93,10 +89,10 @@ mod tests {
         let timestamp: u64 =
             SystemTime::now().duration_since(SystemTime::UNIX_EPOCH).unwrap().as_secs();
 
-        let hello_ack = HelloAck::new(version, ChainType::Mainnet, services, timestamp);
+        let hello_ack = HelloAck::new(version, services, timestamp);
         let msg: Message = hello_ack.clone().into();
 
-        // Hello message cannot be converted to HelloAck message
+        // HelloAck message cannot be converted to Hello message
         // even if the representation of the messages is exactly the same
         assert_eq!(
             Hello::try_from(msg.clone()),

p2p/src/util/src/lib.rs

@@ -63,7 +63,7 @@ pub fn message(input: TokenStream) -> TokenStream {
             fn into(self) -> Message {
                 let encoded = self.encode();
                 Message {
-                    magic: MAGIC_BYTES,
+                    magic: CHAIN_CONFIG.magic_bytes,
                     msg_type: MessageType::#ident,
                     size: encoded.len() as u32,
                     payload: encoded,