Added LightClientBootstrap V1 (#3711)

## Issue Addressed

Partially addresses #3651

## Proposed Changes

Adds server-side support for light_client_bootstrap_v1 topic

## Additional Info

This PR, creates each time a bootstrap without using cache, I do not know how necessary a cache is in this case as this topic is not supposed to be called frequently and IMHO we can just prevent abuse by using the limiter, but let me know what you think or if there is any caveat to this, or if it is necessary only for the sake of good practice.


Co-authored-by: Pawan Dhananjay <pawandhananjay@gmail.com>

beacon_node/lighthouse_network/src/rpc/protocol.rs

@@ -153,6 +153,8 @@ pub enum Protocol {
     Ping,
     /// The `MetaData` protocol name.
     MetaData,
+    /// The `LightClientBootstrap` protocol name.
+    LightClientBootstrap,
 }
 
 /// RPC Versions
@@ -179,6 +181,7 @@ impl std::fmt::Display for Protocol {
             Protocol::BlocksByRoot => "beacon_blocks_by_root",
             Protocol::Ping => "ping",
             Protocol::MetaData => "metadata",
+            Protocol::LightClientBootstrap => "light_client_bootstrap",
         };
         f.write_str(repr)
     }
@@ -207,6 +210,7 @@ impl std::fmt::Display for Version {
 pub struct RPCProtocol<TSpec: EthSpec> {
     pub fork_context: Arc<ForkContext>,
     pub max_rpc_size: usize,
+    pub enable_light_client_server: bool,
     pub phantom: PhantomData<TSpec>,
 }
 
@@ -216,7 +220,7 @@ impl<TSpec: EthSpec> UpgradeInfo for RPCProtocol<TSpec> {
 
     /// The list of supported RPC protocols for Lighthouse.
     fn protocol_info(&self) -> Self::InfoIter {
-        vec![
+        let mut supported_protocols = vec![
             ProtocolId::new(Protocol::Status, Version::V1, Encoding::SSZSnappy),
             ProtocolId::new(Protocol::Goodbye, Version::V1, Encoding::SSZSnappy),
             // V2 variants have higher preference then V1
@@ -227,7 +231,15 @@ impl<TSpec: EthSpec> UpgradeInfo for RPCProtocol<TSpec> {
             ProtocolId::new(Protocol::Ping, Version::V1, Encoding::SSZSnappy),
             ProtocolId::new(Protocol::MetaData, Version::V2, Encoding::SSZSnappy),
             ProtocolId::new(Protocol::MetaData, Version::V1, Encoding::SSZSnappy),
-        ]
+        ];
+        if self.enable_light_client_server {
+            supported_protocols.push(ProtocolId::new(
+                Protocol::LightClientBootstrap,
+                Version::V1,
+                Encoding::SSZSnappy,
+            ));
+        }
+        supported_protocols
     }
 }
 
@@ -289,6 +301,10 @@ impl ProtocolId {
                 <Ping as Encode>::ssz_fixed_len(),
                 <Ping as Encode>::ssz_fixed_len(),
             ),
+            Protocol::LightClientBootstrap => RpcLimits::new(
+                <LightClientBootstrapRequest as Encode>::ssz_fixed_len(),
+                <LightClientBootstrapRequest as Encode>::ssz_fixed_len(),
+            ),
             Protocol::MetaData => RpcLimits::new(0, 0), // Metadata requests are empty
         }
     }
@@ -312,6 +328,10 @@ impl ProtocolId {
                 <MetaDataV1<T> as Encode>::ssz_fixed_len(),
                 <MetaDataV2<T> as Encode>::ssz_fixed_len(),
             ),
+            Protocol::LightClientBootstrap => RpcLimits::new(
+                <LightClientBootstrapRequest as Encode>::ssz_fixed_len(),
+                <LightClientBootstrapRequest as Encode>::ssz_fixed_len(),
+            ),
         }
     }
 
@@ -417,57 +437,13 @@ pub enum InboundRequest<TSpec: EthSpec> {
     Goodbye(GoodbyeReason),
     BlocksByRange(OldBlocksByRangeRequest),
     BlocksByRoot(BlocksByRootRequest),
+    LightClientBootstrap(LightClientBootstrapRequest),
     Ping(Ping),
     MetaData(PhantomData<TSpec>),
 }
 
-impl<TSpec: EthSpec> UpgradeInfo for InboundRequest<TSpec> {
-    type Info = ProtocolId;
-    type InfoIter = Vec<Self::Info>;
-
-    // add further protocols as we support more encodings/versions
-    fn protocol_info(&self) -> Self::InfoIter {
-        self.supported_protocols()
-    }
-}
-
 /// Implements the encoding per supported protocol for `RPCRequest`.
 impl<TSpec: EthSpec> InboundRequest<TSpec> {
-    pub fn supported_protocols(&self) -> Vec<ProtocolId> {
-        match self {
-            // add more protocols when versions/encodings are supported
-            InboundRequest::Status(_) => vec![ProtocolId::new(
-                Protocol::Status,
-                Version::V1,
-                Encoding::SSZSnappy,
-            )],
-            InboundRequest::Goodbye(_) => vec![ProtocolId::new(
-                Protocol::Goodbye,
-                Version::V1,
-                Encoding::SSZSnappy,
-            )],
-            InboundRequest::BlocksByRange(_) => vec![
-                // V2 has higher preference when negotiating a stream
-                ProtocolId::new(Protocol::BlocksByRange, Version::V2, Encoding::SSZSnappy),
-                ProtocolId::new(Protocol::BlocksByRange, Version::V1, Encoding::SSZSnappy),
-            ],
-            InboundRequest::BlocksByRoot(_) => vec![
-                // V2 has higher preference when negotiating a stream
-                ProtocolId::new(Protocol::BlocksByRoot, Version::V2, Encoding::SSZSnappy),
-                ProtocolId::new(Protocol::BlocksByRoot, Version::V1, Encoding::SSZSnappy),
-            ],
-            InboundRequest::Ping(_) => vec![ProtocolId::new(
-                Protocol::Ping,
-                Version::V1,
-                Encoding::SSZSnappy,
-            )],
-            InboundRequest::MetaData(_) => vec![
-                ProtocolId::new(Protocol::MetaData, Version::V2, Encoding::SSZSnappy),
-                ProtocolId::new(Protocol::MetaData, Version::V1, Encoding::SSZSnappy),
-            ],
-        }
-    }
-
     /* These functions are used in the handler for stream management */
 
     /// Number of responses expected for this request.
@@ -479,6 +455,7 @@ impl<TSpec: EthSpec> InboundRequest<TSpec> {
             InboundRequest::BlocksByRoot(req) => req.block_roots.len() as u64,
             InboundRequest::Ping(_) => 1,
             InboundRequest::MetaData(_) => 1,
+            InboundRequest::LightClientBootstrap(_) => 1,
         }
     }
 
@@ -491,6 +468,7 @@ impl<TSpec: EthSpec> InboundRequest<TSpec> {
             InboundRequest::BlocksByRoot(_) => Protocol::BlocksByRoot,
             InboundRequest::Ping(_) => Protocol::Ping,
             InboundRequest::MetaData(_) => Protocol::MetaData,
+            InboundRequest::LightClientBootstrap(_) => Protocol::LightClientBootstrap,
         }
     }
 
@@ -506,6 +484,7 @@ impl<TSpec: EthSpec> InboundRequest<TSpec> {
             InboundRequest::Goodbye(_) => unreachable!(),
             InboundRequest::Ping(_) => unreachable!(),
             InboundRequest::MetaData(_) => unreachable!(),
+            InboundRequest::LightClientBootstrap(_) => unreachable!(),
         }
     }
 }
@@ -609,6 +588,9 @@ impl<TSpec: EthSpec> std::fmt::Display for InboundRequest<TSpec> {
             InboundRequest::BlocksByRoot(req) => write!(f, "Blocks by root: {:?}", req),
             InboundRequest::Ping(ping) => write!(f, "Ping: {}", ping.data),
             InboundRequest::MetaData(_) => write!(f, "MetaData request"),
+            InboundRequest::LightClientBootstrap(bootstrap) => {
+                write!(f, "LightClientBootstrap: {}", bootstrap.root)
+            }
         }
     }
 }