From e5205dfbe6a4a89c33c41d5aed1544d47e27af75 Mon Sep 17 00:00:00 2001
From: tuexen <tuexen@FreeBSD.org>
Date: Sun, 31 May 2015 12:11:05 +0000
Subject: [PATCH] A TCP checksum of 0 is completely valid. Mapping 0 to 0xffff
 only applies to UDP and UDP-Lite.

MFC after: 3 days
---
 contrib/traceroute/traceroute.c | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/contrib/traceroute/traceroute.c b/contrib/traceroute/traceroute.c
index 9ec655f5bdb2..28ba67b51f2d 100644
--- a/contrib/traceroute/traceroute.c
+++ b/contrib/traceroute/traceroute.c
@@ -1470,10 +1470,8 @@ tcp_prep(struct outdata *outdata)
 	tcp->th_flags = TH_SYN;
 	tcp->th_sum = 0;
 
-	if (doipcksum) {
-	    u_short sum = p_cksum(outip, (u_short*)tcp, protlen, protlen);
-	    tcp->th_sum = (sum) ? sum : 0xffff;
-	}
+	if (doipcksum)
+	    tcp->th_sum = p_cksum(outip, (u_short*)tcp, protlen, protlen);
 }
 
 int