From 7b9ca3e9d9b5837dd79adc863f1bac9b19c25983 Mon Sep 17 00:00:00 2001
From: "mergify[bot]" <37929162+mergify[bot]@users.noreply.github.com>
Date: Tue, 4 Jan 2022 16:31:59 +0000
Subject: [PATCH] Flip iter operations to keep associated
 address/header/packets together (backport #22245) (#22256)

* Flip iter operations to keep associated address/header/packets together (#22245)

Flip iter operations to keep associated address/header/packets together

Before this change, if cast_socket_addr() returned a None for any
address/header pair, the subsequent zip() would misalign the
address/header pair and packet. So, this change zips all three together,
then does filter_map() so keep things aligned.

Additionally, compute total_size inline to avoid running through packets
a second time.

(cherry picked from commit 20b61e28b61bf0e327f749a079276bc89d2dcc45)

# Conflicts:
#	streamer/src/recvmmsg.rs

* removes backport merge conflicts

Co-authored-by: steviez <steven@solana.com>
Co-authored-by: behzad nouri <behzadnouri@gmail.com>
---
 streamer/src/recvmmsg.rs | 17 ++++++++---------
 1 file changed, 8 insertions(+), 9 deletions(-)

diff --git a/streamer/src/recvmmsg.rs b/streamer/src/recvmmsg.rs
index 0a9e25d908..28337d8485 100644
--- a/streamer/src/recvmmsg.rs
+++ b/streamer/src/recvmmsg.rs
@@ -99,21 +99,20 @@ pub fn recv_mmsg(sock: &UdpSocket, packets: &mut [Packet]) -> io::Result<(usize,
         return Err(io::Error::last_os_error());
     }
     let mut npkts = 0;
-    addrs
-        .iter()
-        .zip(&hdrs)
+    let mut total_size = 0;
+
+    izip!(&addrs, &hdrs, packets.iter_mut())
         .take(nrecv as usize)
-        .filter_map(|(addr, hdr)| {
-            let addr = cast_socket_addr(addr, &hdr)?.to_std();
-            Some((addr, hdr))
+        .filter_map(|(addr, hdr, pkt)| {
+            let addr = cast_socket_addr(addr, hdr)?.to_std();
+            Some((addr, hdr, pkt))
         })
-        .zip(packets.iter_mut())
-        .for_each(|((addr, hdr), pkt)| {
+        .for_each(|(addr, hdr, pkt)| {
             pkt.meta.size = hdr.msg_len as usize;
             pkt.meta.set_addr(&addr);
             npkts += 1;
+            total_size += pkt.meta.size;
         });
-    let total_size = packets.iter().take(npkts).map(|pkt| pkt.meta.size).sum();
     Ok((total_size, npkts))
 }