feat: add ability to restrict submissions to rproxies only (#805)

## 📝 Summary

Add a flag that would allow restricting submissions to bloxroute
rproxies only.

## ✅ I have completed the following steps:

* [x] Run `make lint`
* [x] Run `make test`
* [ ] Added tests (if applicable)

Author: efbig

crates/rbuilder/src/integration/playground.rs

@@ -161,6 +161,7 @@ impl Playground {
             Vec::new(),
             false,
             false,
+            false,
         );
 
         let payload = client

crates/rbuilder/src/live_builder/block_output/relay_submit.rs

@@ -650,6 +650,7 @@ async fn submit_bid_to_the_relay(
         Err(SubmitBlockErr::InvalidUrl(error)) => {
             error!(err = ?error, "Error parsing URL");
         }
+        Err(SubmitBlockErr::NoRproxyAvailable) => {} // noop
     }
 }
 

crates/rbuilder/src/live_builder/config.rs

@@ -306,6 +306,7 @@ impl L1Config {
                         relay_config.api_token_header.clone(),
                         relay_config.is_bloxroute,
                         relay_config.bloxroute_rproxy_regions.clone(),
+                        relay_config.bloxroute_rproxy_only,
                         relay_config
                             .ask_for_filtering_validators
                             .unwrap_or(DEFAULT_ASK_FOR_FILTERING_VALIDATORS),
@@ -951,6 +952,7 @@ lazy_static! {
                 adjustment_fee_payer: None,
                 is_bloxroute: false,
                 bloxroute_rproxy_regions: Vec::new(),
+                bloxroute_rproxy_only: false,
                 ask_for_filtering_validators: None,
                 can_ignore_gas_limit: None,
             },
@@ -978,6 +980,7 @@ lazy_static! {
                 adjustment_fee_payer: None,
                 is_bloxroute: false,
                 bloxroute_rproxy_regions: Vec::new(),
+                bloxroute_rproxy_only: false,
                 ask_for_filtering_validators: None,
                 can_ignore_gas_limit: None,
             },
@@ -1005,6 +1008,7 @@ lazy_static! {
                 adjustment_fee_payer: None,
                 is_bloxroute: false,
                 bloxroute_rproxy_regions: Vec::new(),
+                bloxroute_rproxy_only: false,
                 ask_for_filtering_validators: None,
                 can_ignore_gas_limit: None,
             },
@@ -1032,6 +1036,7 @@ lazy_static! {
                 adjustment_fee_payer: None,
                 is_bloxroute: false,
                 bloxroute_rproxy_regions: Vec::new(),
+                bloxroute_rproxy_only: false,
                 ask_for_filtering_validators: None,
                 can_ignore_gas_limit: None,
             },
@@ -1059,6 +1064,7 @@ lazy_static! {
                 adjustment_fee_payer: None,
                 is_bloxroute: false,
                 bloxroute_rproxy_regions: Vec::new(),
+                bloxroute_rproxy_only: false,
                 ask_for_filtering_validators: None,
                 can_ignore_gas_limit: None,
             },

crates/rbuilder/src/mev_boost/mod.rs

@@ -98,6 +98,9 @@ pub struct RelayConfig {
     /// The list of bloxroute rproxy regions to send to order by preference.
     #[serde(default)]
     pub bloxroute_rproxy_regions: Vec<String>,
+    /// Flag indicating whether the builder should only submit to rproxy endpoinds if available.
+    #[serde(default)]
+    pub bloxroute_rproxy_only: bool,
     /// Adds "filtering=true" as query to the call relay/v1/builder/validators to get all validators (including those filtering OFAC)
     /// On 2025/06/24 (my birthday!) only supported by ultrasound.
     /// None -> false
@@ -162,6 +165,8 @@ pub struct RelayClient {
     is_bloxroute: bool,
     /// Bloxroute rproxy regions.
     bloxroute_rproxy_regions: Vec<String>,
+    /// Flag indicating whether rproxy regions are required.
+    bloxroute_rproxy_only: bool,
     /// Adds "filtering=true" as query
     ask_for_filtering_validators: bool,
     /// If we submit a block with a different gas than the one the validator registered with in this relay the relay does not mind.
@@ -177,6 +182,7 @@ impl RelayClient {
         api_token_header: Option<String>,
         is_bloxroute: bool,
         bloxroute_rproxy_regions: Vec<String>,
+        bloxroute_rproxy_only: bool,
         ask_for_filtering_validators: bool,
         can_ignore_gas_limit: bool,
     ) -> Self {
@@ -189,6 +195,7 @@ impl RelayClient {
             api_token_header,
             is_bloxroute,
             bloxroute_rproxy_regions,
+            bloxroute_rproxy_only,
             ask_for_filtering_validators,
             can_ignore_gas_limit,
         }
@@ -204,6 +211,7 @@ impl RelayClient {
             Vec::new(),
             false,
             false,
+            false,
         )
     }
 
@@ -523,6 +531,8 @@ pub enum SubmitBlockErr {
     InvalidHeader,
     #[error("Block known")]
     BlockKnown,
+    #[error("No rproxy available")]
+    NoRproxyAvailable,
     #[error("gRPC error")]
     Grpc(#[from] Box<tonic::Status>),
 }
@@ -937,6 +947,8 @@ impl RelayClient {
                 error!(?error, url = %regional.http_endpoint, "Error parsing rproxy URL");
                 SubmitBlockErr::InvalidUrl(error)
             });
+        } else if self.bloxroute_rproxy_only {
+            return Err(SubmitBlockErr::NoRproxyAvailable);
         }
 
         if self.is_bloxroute {
@@ -1254,8 +1266,17 @@ mod tests {
         let mut generator = TestDataGenerator::default();
 
         let relay_url = Url::from_str(&srv.endpoint()).unwrap();
-        let relay =
-            RelayClient::from_url(relay_url, None, None, None, false, Vec::new(), false, false);
+        let relay = RelayClient::from_url(
+            relay_url,
+            None,
+            None,
+            None,
+            false,
+            Vec::new(),
+            false,
+            false,
+            false,
+        );
         let submission = SubmitBlockRequest {
             request: Arc::new(generator.create_deneb_submit_block_request()),
             adjustment_data: None,

crates/test-relay/src/main.rs

@@ -101,7 +101,17 @@ async fn main() -> eyre::Result<()> {
 
     let relay = {
         let url: Url = cli.relay.parse()?;
-        let client = RelayClient::from_url(url, None, None, None, false, Vec::new(), false, false);
+        let client = RelayClient::from_url(
+            url,
+            None,
+            None,
+            None,
+            false,
+            Vec::new(),
+            false,
+            false,
+            false,
+        );
         MevBoostRelaySlotInfoProvider::new(client, "relay".to_string())
     };