From d15675ad7f41978ceb11ea6261b9b03fb204d156 Mon Sep 17 00:00:00 2001
From: behzad nouri <behzadnouri@gmail.com>
Date: Mon, 12 Oct 2020 15:38:08 -0400
Subject: [PATCH] builds a predicate for checking pull requests

---
 core/src/cluster_info.rs | 51 ++++++++++++++++++++--------------------
 1 file changed, 26 insertions(+), 25 deletions(-)

diff --git a/core/src/cluster_info.rs b/core/src/cluster_info.rs
index 83afa7f1927742..802b2d03474964 100644
--- a/core/src/cluster_info.rs
+++ b/core/src/cluster_info.rs
@@ -28,7 +28,7 @@ use crate::{
 };
 
 use rand::distributions::{Distribution, WeightedIndex};
-use rand::SeedableRng;
+use rand::{CryptoRng, Rng, SeedableRng};
 use rand_chacha::ChaChaRng;
 use solana_sdk::sanitize::{Sanitize, SanitizeError};
 
@@ -1812,20 +1812,22 @@ impl ClusterInfo {
         }
     }
 
-    // Filters out pull requests from invalid addresses, and those which have
-    // not passed the ping-pong check. Appends ping packets for the addresses
-    // which need to be (re)verified.
-    fn filter_pull_requests(
-        &self,
-        requests: Vec<PullData>,
-        packets: &mut Packets,
-    ) -> Vec<PullData> {
-        let mut rng = rand::thread_rng();
+    // Returns a predicate checking if the pull request is from a valid
+    // address, and if the address have responded to a ping request. Also
+    // appends ping packets for the addresses which need to be (re)verified.
+    fn check_pull_request<'a, R>(
+        &'a self,
+        now: Instant,
+        mut rng: &'a mut R,
+        packets: &'a mut Packets,
+    ) -> impl FnMut(&PullData) -> bool + 'a
+    where
+        R: Rng + CryptoRng,
+    {
         let mut cache = HashMap::<(Pubkey, SocketAddr), bool>::new();
-        let mut pingf = || Ping::new_rand(&mut rng, &self.keypair).ok();
+        let mut pingf = move || Ping::new_rand(&mut rng, &self.keypair).ok();
         let mut ping_cache = self.ping_cache.write().unwrap();
-        let now = Instant::now();
-        let mut hard_check = |node| {
+        let mut hard_check = move |node| {
             let (_check, ping) = ping_cache.check(now, node, &mut pingf);
             if let Some(ping) = ping {
                 let ping = Protocol::PingMessage(ping);
@@ -1833,22 +1835,19 @@ impl ClusterInfo {
                 packets.packets.push(ping);
             }
             // TODO: For backward compatibility, this unconditionally returns
-            // true for now. This has to return _check, once nodes start
+            // true for now. It has to return _check, once nodes start
             // responding to ping messages.
             true
         };
         // Because pull-responses are sent back to packet.meta.addr() of
         // incoming pull-requests, pings are also sent to request.from_addr (as
         // opposed to caller.gossip address).
-        requests
-            .into_iter()
-            .filter(|request| {
-                ContactInfo::is_valid_address(&request.from_addr) && {
-                    let node = (request.caller.pubkey(), request.from_addr);
-                    *cache.entry(node).or_insert_with(|| hard_check(node))
-                }
-            })
-            .collect()
+        move |request| {
+            ContactInfo::is_valid_address(&request.from_addr) && {
+                let node = (request.caller.pubkey(), request.from_addr);
+                *cache.entry(node).or_insert_with(|| hard_check(node))
+            }
+        }
     }
 
     // Pull requests take an incoming bloom filter of contained entries from a node
@@ -1863,10 +1862,12 @@ impl ClusterInfo {
         self.time_gossip_write_lock("process_pull_reqs", &self.stats.process_pull_requests)
             .process_pull_requests(requests.iter().map(|r| r.caller.clone()), timestamp());
         self.update_data_budget(stakes);
+        let mut rng = rand::thread_rng();
         let mut packets = Packets::new_with_recycler(recycler.clone(), 64, "handle_pull_requests");
-        let (caller_and_filters, addrs): (Vec<_>, Vec<_>) = self
-            .filter_pull_requests(requests, &mut packets)
+        let check_pull_request = self.check_pull_request(Instant::now(), &mut rng, &mut packets);
+        let (caller_and_filters, addrs): (Vec<_>, Vec<_>) = requests
             .into_iter()
+            .filter(check_pull_request)
             .map(|r| ((r.caller, r.filter), r.from_addr))
             .unzip();
         let now = timestamp();