revises turbine peers shuffling order (solana-labs#20480)

Turbine randomly shuffles cluster nodes on a broadcast tree for each
shred. This requires knowing the stakes and nodes' contact-infos (from
gossip).

However gossip is subject to partitioning and propogation delays.
Additionally unstaked nodes may join and leave the cluster at any
moment, changing the cluster view from one node to another.

This commit:
* Always arranges the unstaked nodes at the bottom of turbine broadcast
  tree.
* Staked nodes are always included regardless of if their contact-info
  is available in gossip or not.
* Uses the unbiased WeightedShuffle construct for shuffling nodes.

core/src/broadcast_stage.rs

@@ -17,7 +17,7 @@ use {
         Sender as CrossbeamSender,
     },
     itertools::Itertools,
-    solana_gossip::cluster_info::{ClusterInfo, ClusterInfoError},
+    solana_gossip::cluster_info::{ClusterInfo, ClusterInfoError, DATA_PLANE_FANOUT},
     solana_ledger::{blockstore::Blockstore, shred::Shred},
     solana_measure::measure::Measure,
     solana_metrics::{inc_new_counter_error, inc_new_counter_info},
@@ -33,6 +33,7 @@ use {
     },
     std::{
         collections::HashMap,
+        iter::repeat,
         net::UdpSocket,
         sync::{
             atomic::{AtomicBool, Ordering},
@@ -412,8 +413,6 @@ pub fn broadcast_shreds(
 ) -> Result<()> {
     let mut result = Ok(());
     let mut shred_select = Measure::start("shred_select");
-    // Only the leader broadcasts shreds.
-    let leader = cluster_info.id();
     let (root_bank, working_bank) = {
         let bank_forks = bank_forks.read().unwrap();
         (bank_forks.root_bank(), bank_forks.working_bank())
@@ -427,12 +426,13 @@ pub fn broadcast_shreds(
                 cluster_nodes_cache.get(slot, &root_bank, &working_bank, cluster_info);
             update_peer_stats(&cluster_nodes, last_datapoint_submit);
             let root_bank = root_bank.clone();
-            shreds.filter_map(move |shred| {
-                let seed = shred.seed(leader, &root_bank);
-                let node = cluster_nodes.get_broadcast_peer(seed)?;
-                socket_addr_space
-                    .check(&node.tvu)
-                    .then(|| (&shred.payload, node.tvu))
+            shreds.flat_map(move |shred| {
+                repeat(&shred.payload).zip(cluster_nodes.get_broadcast_addrs(
+                    shred,
+                    &root_bank,
+                    DATA_PLANE_FANOUT,
+                    socket_addr_space,
+                ))
             })
         })
         .collect();

core/src/broadcast_stage/broadcast_duplicates_run.rs

@@ -3,6 +3,7 @@ use {
     crate::cluster_nodes::ClusterNodesCache,
     itertools::Itertools,
     solana_entry::entry::Entry,
+    solana_gossip::cluster_info::DATA_PLANE_FANOUT,
     solana_ledger::shred::Shredder,
     solana_sdk::{
         hash::Hash,
@@ -246,6 +247,11 @@ impl BroadcastRun for BroadcastDuplicatesRun {
             (bank_forks.root_bank(), bank_forks.working_bank())
         };
         let self_pubkey = cluster_info.id();
+        let nodes: Vec<_> = cluster_info
+            .all_peers()
+            .into_iter()
+            .map(|(node, _)| node)
+            .collect();
 
         // Creat cluster partition.
         let cluster_partition: HashSet<Pubkey> = {
@@ -273,8 +279,11 @@ impl BroadcastRun for BroadcastDuplicatesRun {
         let packets: Vec<_> = shreds
             .iter()
             .filter_map(|shred| {
-                let seed = shred.seed(self_pubkey, &root_bank);
-                let node = cluster_nodes.get_broadcast_peer(seed)?;
+                let addr = cluster_nodes
+                    .get_broadcast_addrs(shred, &root_bank, DATA_PLANE_FANOUT, socket_addr_space)
+                    .first()
+                    .copied()?;
+                let node = nodes.iter().find(|node| node.tvu == addr)?;
                 if !socket_addr_space.check(&node.tvu) {
                     return None;
                 }