netfilter: payload_len is be16, add size of struct rather than size of pointer

payload_len is a be16 value, not cpu_endian, also the size of a ponter
to a struct ipv6hdr was being added, not the size of the struct itself.
Signed-off-by: NHarvey Harrison <harvey.harrison@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/netfilter/ipvs/ip_vs_xmit.c

@@ -713,7 +713,8 @@ ip_vs_tunnel_xmit_v6(struct sk_buff *skb, struct ip_vs_conn *cp,
 	iph			=	ipv6_hdr(skb);
 	iph->version		=	6;
 	iph->nexthdr		=	IPPROTO_IPV6;
-	iph->payload_len	=	old_iph->payload_len + sizeof(old_iph);
+	iph->payload_len	=	old_iph->payload_len;
+	be16_add_cpu(&iph->payload_len, sizeof(*old_iph));
 	iph->priority		=	old_iph->priority;
 	memset(&iph->flow_lbl, 0, sizeof(iph->flow_lbl));
 	iph->daddr		=	rt->rt6i_dst.addr;