There is no need to try to attach IPv6 to an interface when the

AUTOCONF6 flag is already set.
This is likely a leftover from when we sent router solicitations from
the kernel. This was a way to trigger sending a solicitation from
userland.
OK kn

diff --git a/sys/net/if.c b/sys/net/if.c
index 912ce49..3e40c59 100644 (file)
--- a/sys/net/if.c
+++ b/sys/net/if.c
@@ -1,4 +1,4 @@
-/*     $OpenBSD: if.c,v 1.635 2021/03/11 15:56:27 deraadt Exp $        */
+/*     $OpenBSD: if.c,v 1.636 2021/03/11 16:48:47 florian Exp $        */
 /*     $NetBSD: if.c,v 1.35 1996/05/07 05:26:04 thorpej Exp $  */
 
 /*
@@ -1958,7 +1958,8 @@ ifioctl(struct socket *so, u_long cmd, caddr_t data, struct proc *p)
 
                NET_LOCK();
 #ifdef INET6
-               if (ISSET(ifr->ifr_flags, IFXF_AUTOCONF6)) {
+               if (ISSET(ifr->ifr_flags, IFXF_AUTOCONF6) &&
+                   !ISSET(ifp->if_xflags, IFXF_AUTOCONF6)) {
                        error = in6_ifattach(ifp);
                        if (error != 0) {
                                NET_UNLOCK();