ipv6: fix the check when handle RA

d9333196572(ipv6: Allow accepting RA from local IP addresses.) made the wrong
check, whether or not to accept RA with source-addr found on local machine, when
accept_ra_from_local is 0.

Fixes: d9333196572(ipv6: Allow accepting RA from local IP addresses.)
Cc: Ben Greear <[e-mail]>
Cc: Hannes Frederic Sowa <[e-mail]>
Signed-off-by: Li RongQing <[e-mail]>
Acked-by: Hannes Frederic Sowa <[e-mail]>
Signed-off-by: David S. Miller <[e-mail]>

net/ipv6/ndisc.c

···
 	/* Do not accept RA with source-addr found on local machine unless
 	 * accept_ra_from_local is set to true.
 	 */
-	if (!(in6_dev->cnf.accept_ra_from_local ||
-	      ipv6_chk_addr(dev_net(in6_dev->dev), &ipv6_hdr(skb)->saddr,
-			    NULL, 0))) {
+	if (!in6_dev->cnf.accept_ra_from_local &&
+	    ipv6_chk_addr(dev_net(in6_dev->dev), &ipv6_hdr(skb)->saddr,
+			  NULL, 0)) {
 		ND_PRINTK(2, info,
 			  "RA from local address detected on dev: %s: default router ignored\n",
 			  skb->dev->name);
···
 	}
 
 #ifdef CONFIG_IPV6_ROUTE_INFO
-	if (!(in6_dev->cnf.accept_ra_from_local ||
-	      ipv6_chk_addr(dev_net(in6_dev->dev), &ipv6_hdr(skb)->saddr,
-			    NULL, 0))) {
+	if (!in6_dev->cnf.accept_ra_from_local &&
+	    ipv6_chk_addr(dev_net(in6_dev->dev), &ipv6_hdr(skb)->saddr,
+			  NULL, 0)) {
 		ND_PRINTK(2, info,
 			  "RA from local address detected on dev: %s: router info ignored.\n",
 			  skb->dev->name);