1 files changed, 11 insertions, 0 deletions

diff --git a/sys/netinet6/ip6_output.c b/sys/netinet6/ip6_output.c
index d6a6e801bc18..d0d072ebf4f8 100644
--- a/sys/netinet6/ip6_output.c
+++ b/sys/netinet6/ip6_output.c
@@ -1366,6 +1366,17 @@ do { \
 
 				case IPV6_V6ONLY:
 					/*
+					 * make setsockopt(IPV6_V6ONLY)
+					 * available only prior to bind(2).
+					 * see ipng mailing list, Jun 22 2001.
+					 */
+					if (in6p->in6p_lport ||
+					    !IN6_IS_ADDR_UNSPECIFIED(&in6p->in6p_laddr))
+					{
+						error = EINVAL;
+						break;
+					}
+					/*
 					 * XXX: BINDV6ONLY should be integrated
 					 * into V6ONLY.
 					 */