dedups turbine retransmit peers by tvu socket addresses (#28944)

No need to send duplicate shreds if several nodes have the same tvu
socket address because they are behind a relayer or whatever.

core/benches/cluster_nodes.rs

@@ -49,7 +49,7 @@ fn get_retransmit_peers_deterministic(
             0,
             0,
         );
-        let (_root_distance, _neighbors, _children) = cluster_nodes.get_retransmit_peers(
+        let _retransmit_peers = cluster_nodes.get_retransmit_peers(
             slot_leader,
             &shred.id(),
             root_bank,

core/src/cluster_nodes.rs

@@ -68,6 +68,16 @@ pub struct ClusterNodesCache<T> {
     ttl: Duration, // Time to live.
 }
 
+pub struct RetransmitPeers<'a> {
+    root_distance: usize, // distance from the root node
+    neighbors: Vec<&'a Node>,
+    children: Vec<&'a Node>,
+    // Maps from tvu/tvu_forwards addresses to the first node
+    // in the shuffle with the same address.
+    addrs: HashMap<SocketAddr, Pubkey>, // tvu addresses
+    frwds: HashMap<SocketAddr, Pubkey>, // tvu_forwards addresses
+}
+
 impl Node {
     #[inline]
     fn pubkey(&self) -> Pubkey {
@@ -139,33 +149,48 @@ impl ClusterNodes<RetransmitStage> {
         root_bank: &Bank,
         fanout: usize,
     ) -> (/*root_distance:*/ usize, Vec<SocketAddr>) {
-        let (root_distance, neighbors, children) =
-            self.get_retransmit_peers(slot_leader, shred, root_bank, fanout);
+        let RetransmitPeers {
+            root_distance,
+            neighbors,
+            children,
+            addrs,
+            frwds,
+        } = self.get_retransmit_peers(slot_leader, shred, root_bank, fanout);
         if neighbors.is_empty() {
-            let peers = children.into_iter().filter_map(Node::contact_info);
-            let addrs = peers.map(|peer| peer.tvu).collect();
-            return (root_distance, addrs);
+            let peers = children
+                .into_iter()
+                .filter_map(Node::contact_info)
+                .filter(|node| addrs.get(&node.tvu) == Some(&node.id))
+                .map(|node| node.tvu)
+                .collect();
+            return (root_distance, peers);
         }
         // If the node is on the critical path (i.e. the first node in each
         // neighborhood), it should send the packet to tvu socket of its
         // children and also tvu_forward socket of its neighbors. Otherwise it
         // should only forward to tvu_forwards socket of its children.
         if neighbors[0].pubkey() != self.pubkey {
-            let addrs = children
-                .iter()
-                .filter_map(|node| Some(node.contact_info()?.tvu_forwards));
-            return (root_distance, addrs.collect());
+            let peers = children
+                .into_iter()
+                .filter_map(Node::contact_info)
+                .filter(|node| frwds.get(&node.tvu_forwards) == Some(&node.id))
+                .map(|node| node.tvu_forwards);
+            return (root_distance, peers.collect());
         }
         // First neighbor is this node itself, so skip it.
-        let addrs = neighbors[1..]
+        let peers = neighbors[1..]
             .iter()
-            .filter_map(|node| Some(node.contact_info()?.tvu_forwards))
+            .filter_map(|node| node.contact_info())
+            .filter(|node| frwds.get(&node.tvu_forwards) == Some(&node.id))
+            .map(|node| node.tvu_forwards)
             .chain(
                 children
-                    .iter()
-                    .filter_map(|node| Some(node.contact_info()?.tvu)),
+                    .into_iter()
+                    .filter_map(Node::contact_info)
+                    .filter(|node| addrs.get(&node.tvu) == Some(&node.id))
+                    .map(|node| node.tvu),
             );
-        (root_distance, addrs.collect())
+        (root_distance, peers.collect())
     }
 
     pub fn get_retransmit_peers(
@@ -174,11 +199,7 @@ impl ClusterNodes<RetransmitStage> {
         shred: &ShredId,
         root_bank: &Bank,
         fanout: usize,
-    ) -> (
-        usize,      // distance from the root node
-        Vec<&Node>, // neighbors
-        Vec<&Node>, // children
-    ) {
+    ) -> RetransmitPeers {
         let shred_seed = shred.seed(slot_leader);
         let mut weighted_shuffle = self.weighted_shuffle.clone();
         // Exclude slot leader from list of nodes.
@@ -187,16 +208,27 @@ impl ClusterNodes<RetransmitStage> {
         } else if let Some(index) = self.index.get(slot_leader) {
             weighted_shuffle.remove_index(*index);
         };
+        let mut addrs = HashMap::<SocketAddr, Pubkey>::with_capacity(self.nodes.len());
+        let mut frwds = HashMap::<SocketAddr, Pubkey>::with_capacity(self.nodes.len());
         let mut rng = ChaChaRng::from_seed(shred_seed);
+        let drop_redundant_turbine_path = drop_redundant_turbine_path(shred.slot(), root_bank);
         let nodes: Vec<_> = weighted_shuffle
             .shuffle(&mut rng)
             .map(|index| &self.nodes[index])
+            .inspect(|node| {
+                if let Some(node) = node.contact_info() {
+                    addrs.entry(node.tvu).or_insert(node.id);
+                    if !drop_redundant_turbine_path {
+                        frwds.entry(node.tvu_forwards).or_insert(node.id);
+                    }
+                }
+            })
             .collect();
         let self_index = nodes
             .iter()
             .position(|node| node.pubkey() == self.pubkey)
             .unwrap();
-        if drop_redundant_turbine_path(shred.slot(), root_bank) {
+        if drop_redundant_turbine_path {
             let root_distance = if self_index == 0 {
                 0
             } else if self_index <= fanout {
@@ -205,7 +237,13 @@ impl ClusterNodes<RetransmitStage> {
                 2
             };
             let peers = get_retransmit_peers(fanout, self_index, &nodes);
-            return (root_distance, Vec::default(), peers.collect());
+            return RetransmitPeers {
+                root_distance,
+                neighbors: Vec::default(),
+                children: peers.collect(),
+                addrs,
+                frwds,
+            };
         }
         let root_distance = if self_index == 0 {
             0
@@ -218,7 +256,13 @@ impl ClusterNodes<RetransmitStage> {
         // Assert that the node itself is included in the set of neighbors, at
         // the right offset.
         debug_assert_eq!(neighbors[self_index % fanout].pubkey(), self.pubkey);
-        (root_distance, neighbors, children)
+        RetransmitPeers {
+            root_distance,
+            neighbors,
+            children,
+            addrs,
+            frwds,
+        }
     }
 }