From 48cb400fb10564bb08e61735d88d4410bd160fb0 Mon Sep 17 00:00:00 2001
From: Ruslan Ermilov <ru@FreeBSD.org>
Date: Tue, 31 Oct 2000 09:13:02 +0000
Subject: [PATCH] Do not waste a time saving a copy of IP header if we are
 certainly not going to send an ICMP error message (net.inet.udp.blackhole=1).

---
 sys/netinet/udp_usrreq.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/sys/netinet/udp_usrreq.c b/sys/netinet/udp_usrreq.c
index f357905568f..589fbef76d1 100644
--- a/sys/netinet/udp_usrreq.c
+++ b/sys/netinet/udp_usrreq.c
@@ -208,7 +208,8 @@ udp_input(m, off, proto)
 	 * Save a copy of the IP header in case we want restore it
 	 * for sending an ICMP error message in response.
 	 */
-	save_ip = *ip;
+	if (!blackhole)
+		save_ip = *ip;
 
 	/*
 	 * Checksum extended UDP header and data.