feat: support relay bid sequencing (#795)

## 📝 Summary

Support relay bid sequencing via `x-sequence` header. Ref:
-
https://docs.ultrasound.money/builders/builder-getting-started#bid-sequencing
-
https://docs.titanrelay.xyz/builders/builder-integration#submission-headers

## ✅ I have completed the following steps:

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

Author: efbig

crates/rbuilder-primitives/src/mev_boost/mod.rs

@@ -200,6 +200,7 @@ pub struct BloxrouteRegionalEndpoint {
 
 #[derive(Clone, Debug)]
 pub struct BidMetadata {
+    pub sequence: u64,
     pub value: BidValueMetadata,
     pub order_ids: Vec<OrderId>,
     pub bundle_hashes: Vec<B256>,

crates/rbuilder-primitives/src/mev_boost/submit_header.rs

@@ -1,12 +1,22 @@
 use crate::mev_boost::{
     adjustment::BidAdjustmentDataV2,
     ssz_roots::{calculate_transactions_root_ssz, calculate_withdrawals_root_ssz},
+    BidMetadata,
 };
 use alloy_primitives::{Address, Bloom, Bytes, B256, U256};
 use alloy_rpc_types_beacon::{relay::BidTrace, requests::ExecutionRequestsV4, BlsSignature};
 use alloy_rpc_types_engine::ExecutionPayloadV3;
 use serde_with::{serde_as, DisplayFromStr};
 
+/// Optimistic V3 bid submission with metadata.
+#[derive(Clone, Debug)]
+pub struct SubmitHeaderRequestWithMetadata {
+    /// Header submission.
+    pub submission: SubmitHeaderRequest,
+    /// Bid metadata.
+    pub metadata: BidMetadata,
+}
+
 /// Optimistic V3 bid submission.
 #[derive(
     PartialEq,
@@ -18,7 +28,7 @@ use serde_with::{serde_as, DisplayFromStr};
     ssz_derive::Encode,
     ssz_derive::Decode,
 )]
-pub struct HeaderSubmissionOptimisticV3 {
+pub struct SubmitHeaderRequest {
     /// URL pointing to the builder's server endpoint for retrieving
     /// the full block payload if this header is selected.
     pub url: Vec<u8>,

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

@@ -26,13 +26,14 @@ use rbuilder_primitives::{
     built_block::{block_to_execution_payload, SignedBuiltBlock},
     mev_boost::{
         BidAdjustmentData, BidMetadata, BidValueMetadata, ExecutionPayloadHeaderElectra,
-        HeaderSubmission, HeaderSubmissionElectra, HeaderSubmissionOptimisticV3, MevBoostRelayID,
-        SignedHeaderSubmission, SubmitBlockRequest, SubmitBlockRequestWithMetadata,
-        ValidatorSlotData,
+        HeaderSubmission, HeaderSubmissionElectra, MevBoostRelayID, SignedHeaderSubmission,
+        SubmitBlockRequest, SubmitBlockRequestWithMetadata, SubmitHeaderRequest,
+        SubmitHeaderRequestWithMetadata, ValidatorSlotData,
     },
 };
 use reth_chainspec::ChainSpec;
 use std::sync::Arc;
+use time::OffsetDateTime;
 use tokio::{
     sync::{broadcast, Notify},
     time::Instant,
@@ -221,12 +222,15 @@ async fn run_submit_to_relays_job(
                 }
             });
 
+        // SAFETY: UNIX timestamp in nanos won't exceed u64::MAX until year 2554
+        let sequence = OffsetDateTime::now_utc().unix_timestamp_nanos() as u64;
         let executed_orders = block
             .trace
             .included_orders
             .iter()
             .flat_map(|exec_res| exec_res.order.original_orders());
         let bid_metadata = BidMetadata {
+            sequence,
             value: BidValueMetadata {
                 coinbase_reward: block.trace.coinbase_reward,
                 top_competitor_bid: block.trace.seen_competition_bid,
@@ -403,7 +407,7 @@ fn create_optimistic_v3_request(
     request: &AlloySubmitBlockRequest,
     maybe_adjustment_data: Option<&BidAdjustmentData>,
     adjustment_data_required: bool,
-) -> eyre::Result<HeaderSubmissionOptimisticV3> {
+) -> eyre::Result<SubmitHeaderRequest> {
     let maybe_adjustment_data_v2 = maybe_adjustment_data.map(|d| d.clone().into_v2());
     if maybe_adjustment_data_v2.is_none() && adjustment_data_required {
         eyre::bail!("adjustment data is required")
@@ -455,7 +459,7 @@ fn create_optimistic_v3_request(
         _ => eyre::bail!("optimistic v3 submission is not supported for this fork"),
     };
 
-    Ok(HeaderSubmissionOptimisticV3 {
+    Ok(SubmitHeaderRequest {
         url: builder_url.to_vec(),
         tx_count: tx_count as u32,
         submission,
@@ -503,7 +507,10 @@ fn submit_block_to_relays(
                     maybe_adjustment_data,
                     relay.optimistic_v3_bid_adjustment_required(),
                 )
-                .map(|request| (config.clone(), request))
+                .map(|request| (config.clone(), SubmitHeaderRequestWithMetadata {
+                    submission: request,
+                    metadata: bid_metadata.clone()
+                }))
                 .inspect_err(|error| {
                     error!(parent: submission_span, ?error, "Unable to create optimistic V3 request");
                 })
@@ -547,7 +554,7 @@ fn submit_block_to_relays(
 async fn submit_bid_to_the_relay(
     relay: &MevBoostRelayBidSubmitter,
     submit_block_request: SubmitBlockRequestWithMetadata,
-    optimistic_v3_request: Option<(OptimisticV3Config, HeaderSubmissionOptimisticV3)>,
+    optimistic_v3_request: Option<(OptimisticV3Config, SubmitHeaderRequestWithMetadata)>,
     registration: ValidatorSlotData,
     optimistic: bool,
     cancel: CancellationToken,

crates/rbuilder/src/mev_boost/mod.rs

@@ -4,8 +4,8 @@ use alloy_rpc_types_beacon::BlsPublicKey;
 use flate2::{write::GzEncoder, Compression};
 use governor::{DefaultDirectRateLimiter, Quota, RateLimiter};
 use rbuilder_primitives::mev_boost::{
-    HeaderSubmissionOptimisticV3, KnownRelay, MevBoostRelayID, RelayMode,
-    SubmitBlockRequestNoBlobs, SubmitBlockRequestWithMetadata, ValidatorRegistration,
+    KnownRelay, MevBoostRelayID, RelayMode, SubmitBlockRequestNoBlobs,
+    SubmitBlockRequestWithMetadata, SubmitHeaderRequestWithMetadata, ValidatorRegistration,
     ValidatorSlotData, MEV_BOOST_SLOT_INFO_REQUEST_TIMEOUT,
 };
 use reqwest::{
@@ -35,6 +35,7 @@ const BUNDLE_HASHES_HEADER: &str = "Bundle-Hashes";
 const TOP_BID_HEADER: &str = "Top-Bid";
 const BLOXROUTE_SHARE_HEADER: &str = "share";
 const BLOXROUTE_BUILDER_VALUE_HEADER: &str = "builder-value";
+const X_SEQUENCE_HEADER: &str = "x-sequence";
 
 const JSON_CONTENT_TYPE: &str = "application/json";
 const SSZ_CONTENT_TYPE: &str = "application/octet-stream";
@@ -343,7 +344,7 @@ impl MevBoostRelayBidSubmitter {
 
     pub async fn submit_optimistic_v3(
         &self,
-        data: HeaderSubmissionOptimisticV3,
+        data: SubmitHeaderRequestWithMetadata,
         registration: ValidatorSlotData,
     ) -> Result<(), SubmitBlockErr> {
         self.client
@@ -702,6 +703,7 @@ impl RelayClient {
         } = submission_with_metadata;
 
         let mut headers = HeaderMap::new();
+        headers.insert(X_SEQUENCE_HEADER, metadata.sequence.into());
         self.add_auth_headers(&mut headers)
             .map_err(|_| SubmitBlockErr::InvalidHeader)?;
 
@@ -899,11 +901,17 @@ impl RelayClient {
 
     pub async fn submit_optimistic_v3(
         &self,
-        request: &HeaderSubmissionOptimisticV3,
+        request: &SubmitHeaderRequestWithMetadata,
         registration: &ValidatorSlotData,
         cancellations: bool,
     ) -> Result<(), SubmitBlockErr> {
+        let SubmitHeaderRequestWithMetadata {
+            submission,
+            metadata,
+        } = request;
+
         let mut headers = HeaderMap::new();
+        headers.insert(X_SEQUENCE_HEADER, metadata.sequence.into());
         self.add_auth_headers(&mut headers)
             .map_err(|_| SubmitBlockErr::InvalidHeader)?;
 
@@ -912,7 +920,7 @@ impl RelayClient {
         url.query_pairs_mut()
             .append_pair("cancellations", if cancellations { "1" } else { "0" });
 
-        let body = request.as_ssz_bytes();
+        let body = submission.as_ssz_bytes();
         headers.insert(CONTENT_TYPE, HeaderValue::from_static(SSZ_CONTENT_TYPE));
 
         let response = self
@@ -1284,6 +1292,7 @@ mod tests {
         let sub_relay = SubmitBlockRequestWithMetadata {
             submission,
             metadata: BidMetadata {
+                sequence: 0,
                 value: BidValueMetadata {
                     coinbase_reward: Default::default(),
                     top_competitor_bid: None,