From: Felix Fietkau <nbd@nbd.name>
Date: Sun, 25 Feb 2018 17:22:55 +0100
Subject: [PATCH] netfilter: nf_flow_table: fix checksum when handling DNAT

Add a missing call to csum_replace4 like on SNAT

Signed-off-by: Felix Fietkau <nbd@nbd.name>
---

--- a/net/netfilter/nf_flow_table_ip.c
+++ b/net/netfilter/nf_flow_table_ip.c
@@ -130,6 +130,7 @@ static int nf_flow_dnat_ip(const struct
 	default:
 		return -1;
 	}
+	csum_replace4(&iph->check, addr, new_addr);
 
 	return nf_flow_nat_ip_l4proto(skb, iph, thoff, addr, new_addr);
 }
