ipv4: Always call ip_options_build() after rest of IP header is filled in.

This will allow ip_options_build() to reliably look at the values of
iph->{daddr,saddr}

Signed-off-by: David S. Miller <davem@davemloft.net>

net/ipv4/ip_output.c

@@ -1327,10 +1327,6 @@ struct sk_buff *__ip_make_skb(struct sock *sk,
 	iph = (struct iphdr *)skb->data;
 	iph->version = 4;
 	iph->ihl = 5;
-	if (opt) {
-		iph->ihl += opt->optlen>>2;
-		ip_options_build(skb, opt, cork->addr, rt, 0);
-	}
 	iph->tos = inet->tos;
 	iph->frag_off = df;
 	ip_select_ident(iph, &rt->dst, sk);
@@ -1339,6 +1335,11 @@ struct sk_buff *__ip_make_skb(struct sock *sk,
 	iph->saddr = fl4->saddr;
 	iph->daddr = fl4->daddr;
 
+	if (opt) {
+		iph->ihl += opt->optlen>>2;
+		ip_options_build(skb, opt, cork->addr, rt, 0);
+	}
+
 	skb->priority = sk->sk_priority;
 	skb->mark = sk->sk_mark;
 	/*