From: Robert Edmonds <edmonds@fsi.io>
Date: Sat, 16 Apr 2016 00:43:34 +0000 (-0400)
Subject: dnswasher: Only zero the IP header checksum for IPv4
X-Git-Tag: dnsdist-1.0.0~9^2~2
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=a8b9d939a7bbef961e825a0088f350ff093f8a04;p=thirdparty%2Fpdns.git

dnswasher: Only zero the IP header checksum for IPv4

IPv6 doesn't have a checksum field. This code previously zeroed the
space in the header where the IPv4 header checksum would be, regardless
of IP header version.
---

diff --git a/pdns/dnswasher.cc b/pdns/dnswasher.cc
index 7032394c4d..d9f0466fa7 100644
--- a/pdns/dnswasher.cc
+++ b/pdns/dnswasher.cc
@@ -82,6 +82,8 @@ try
           *dst=htonl(ipo.obf4(*dst));
         else
           *src=htonl(ipo.obf4(*src));
+
+        pr.d_ip->ip_sum=0;
       } else if (pr.d_ip->ip_v == 6) {
         uint64_t *src=1+(uint64_t*)&pr.d_ip6->ip6_src;
         uint64_t *dst=1+(uint64_t*)&pr.d_ip6->ip6_dst;
@@ -91,7 +93,6 @@ try
         else
           *src=ipo.obf6(*src);
       }
-      pr.d_ip->ip_sum=0;
       pw.write();
     }
   }