ipv4: call __ip_options_echo() in cookie_v4_check()

commit 971f10ec ("tcp: better TCP_SKB_CB layout to reduce cache line misses")
missed that cookie_v4_check() still calls ip_options_echo() which uses
IPCB(). It should use TCPCB() at TCP layer, so call __ip_options_echo()
instead.

Fixes: commit 971f10ec ("tcp: better TCP_SKB_CB layout to reduce cache line misses")
Cc: Krzysztof Kolasa <kkolasa@winsoft.pl>
Cc: Eric Dumazet <edumazet@google.com>
Reported-by: NKrzysztof Kolasa <kkolasa@winsoft.pl>
Tested-by: NKrzysztof Kolasa <kkolasa@winsoft.pl>
Signed-off-by: NCong Wang <cwang@twopensource.com>
Signed-off-by: NCong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/ipv4/syncookies.c

@@ -321,7 +321,7 @@ struct sock *cookie_v4_check(struct sock *sk, struct sk_buff *skb,
 		int opt_size = sizeof(struct ip_options_rcu) + opt->optlen;
 
 		ireq->opt = kmalloc(opt_size, GFP_ATOMIC);
-		if (ireq->opt != NULL && ip_options_echo(&ireq->opt->opt, skb)) {
+		if (ireq->opt != NULL && __ip_options_echo(&ireq->opt->opt, skb, opt)) {
 			kfree(ireq->opt);
 			ireq->opt = NULL;
 		}