enable repair ping/pong cache (solana-labs#28408)

core/src/serve_repair.rs

@@ -166,6 +166,8 @@ struct ServeRepairStats {
     orphan: usize,
     pong: usize,
     ancestor_hashes: usize,
+    ping_cache_check_failed: usize,
+    pings_sent: usize,
     err_time_skew: usize,
     err_malformed: usize,
     err_sig_verify: usize,
@@ -531,6 +533,12 @@ impl ServeRepair {
                 i64
             ),
             ("pong", stats.pong, i64),
+            (
+                "ping_cache_check_failed",
+                stats.ping_cache_check_failed,
+                i64
+            ),
+            ("pings_sent", stats.pings_sent, i64),
             ("err_time_skew", stats.err_time_skew, i64),
             ("err_malformed", stats.err_malformed, i64),
             ("err_sig_verify", stats.err_sig_verify, i64),
@@ -659,6 +667,43 @@ impl ServeRepair {
         true
     }
 
+    fn check_ping_cache(
+        ping_cache: &mut PingCache,
+        request: &RepairProtocol,
+        from_addr: &SocketAddr,
+        identity_keypair: &Keypair,
+    ) -> (bool, Option<Packet>) {
+        let mut rng = rand::thread_rng();
+        let mut pingf = move || Ping::new_rand(&mut rng, identity_keypair).ok();
+        let (check, ping) =
+            ping_cache.check(Instant::now(), (*request.sender(), *from_addr), &mut pingf);
+        let ping_pkt = if let Some(ping) = ping {
+            match request {
+                RepairProtocol::LegacyWindowIndex(_, _, _)
+                | RepairProtocol::LegacyHighestWindowIndex(_, _, _)
+                | RepairProtocol::LegacyOrphan(_, _)
+                | RepairProtocol::LegacyWindowIndexWithNonce(_, _, _, _)
+                | RepairProtocol::LegacyHighestWindowIndexWithNonce(_, _, _, _)
+                | RepairProtocol::LegacyOrphanWithNonce(_, _, _)
+                | RepairProtocol::WindowIndex { .. }
+                | RepairProtocol::HighestWindowIndex { .. }
+                | RepairProtocol::Orphan { .. } => {
+                    let ping = RepairResponse::Ping(ping);
+                    Packet::from_data(Some(from_addr), ping).ok()
+                }
+                RepairProtocol::LegacyAncestorHashes(_, _, _)
+                | RepairProtocol::AncestorHashes { .. } => {
+                    let ping = AncestorHashesResponse::Ping(ping);
+                    Packet::from_data(Some(from_addr), ping).ok()
+                }
+                RepairProtocol::Pong(_) => None,
+            }
+        } else {
+            None
+        };
+        (check, ping_pkt)
+    }
+
     fn handle_packets(
         &self,
         ping_cache: &mut PingCache,
@@ -672,6 +717,8 @@ impl ServeRepair {
     ) {
         let identity_keypair = self.cluster_info.keypair().clone();
         let my_id = identity_keypair.pubkey();
+        let socket_addr_space = *self.cluster_info.socket_addr_space();
+        let mut pending_pings = Vec::default();
 
         // iter over the packets
         for (i, packet) in packet_batch.iter().enumerate() {
@@ -683,6 +730,12 @@ impl ServeRepair {
                 }
             };
 
+            let from_addr = packet.meta.socket_addr();
+            if !ContactInfo::is_valid_address(&from_addr, &socket_addr_space) {
+                stats.err_malformed += 1;
+                continue;
+            }
+
             let staked = epoch_staked_nodes
                 .as_ref()
                 .map(|nodes| nodes.contains_key(request.sender()))
@@ -704,7 +757,18 @@ impl ServeRepair {
                 stats.unsigned_requests += 1;
             }
 
-            let from_addr = packet.meta.socket_addr();
+            if !matches!(&request, RepairProtocol::Pong(_)) {
+                let (check, ping_pkt) =
+                    Self::check_ping_cache(ping_cache, &request, &from_addr, &identity_keypair);
+                if let Some(ping_pkt) = ping_pkt {
+                    pending_pings.push(ping_pkt);
+                }
+                if !check {
+                    // collect stats for ping/pong verification
+                    stats.ping_cache_check_failed += 1;
+                }
+            }
+
             stats.processed += 1;
             let rsp = match Self::handle_repair(
                 recycler, &from_addr, blockstore, request, stats, ping_cache,
@@ -726,6 +790,12 @@ impl ServeRepair {
                 break;
             }
         }
+
+        if !pending_pings.is_empty() {
+            stats.pings_sent += pending_pings.len();
+            let batch = PacketBatch::new(pending_pings);
+            let _ignore = response_sender.send(batch);
+        }
     }
 
     pub fn ancestor_repair_request_bytes(