nd6: don't force inet6 params off for bridgelf/dev/bridge-inet6-params

currently, nd6 forces ND6_IFF_AUTO_LINKLOCAL and ND6_IFF_ACCEPT_RTADV to
be disabled for IFT_BRIDGE interfaces.  delete this, as there is no
reason to behave this way.

in the past, this might have made sense when adding IP addresses to a
bridge could create strange behaviour, in particular relating to
link-local scope violations as described in the "IPv6 support" section
of bridge(4).

however, nowadays the only reason IPv6 would be enabled on a bridge is
because the admin explicitly enabled that, in which case they will
expect this to work like any other interface.

PR:	254445
Reported by:	John W. O'Brien <john@saltant.com>

1 files changed, 3 insertions, 12 deletions

diff --git a/sys/netinet6/nd6.c b/sys/netinet6/nd6.c
index 887da1ebe21a..fb95dac29c12 100644
--- a/sys/netinet6/nd6.c
+++ b/sys/netinet6/nd6.c
@@ -297,23 +297,14 @@ nd6_ifattach(struct ifnet *ifp)
 		nd->flags |= ND6_IFF_IFDISABLED;
 
 	/* A loopback interface always has ND6_IFF_AUTO_LINKLOCAL.
-	 * XXXHRS: Clear ND6_IFF_AUTO_LINKLOCAL on an IFT_BRIDGE interface by
-	 * default regardless of the V_ip6_auto_linklocal configuration to
-	 * give a reasonable default behavior.
 	 */
-	if ((V_ip6_auto_linklocal && ifp->if_type != IFT_BRIDGE &&
-	    ifp->if_type != IFT_WIREGUARD) || (ifp->if_flags & IFF_LOOPBACK))
+	if ((V_ip6_auto_linklocal && ifp->if_type != IFT_WIREGUARD) ||
+	    (ifp->if_flags & IFF_LOOPBACK))
 		nd->flags |= ND6_IFF_AUTO_LINKLOCAL;
 	/*
 	 * A loopback interface does not need to accept RTADV.
-	 * XXXHRS: Clear ND6_IFF_ACCEPT_RTADV on an IFT_BRIDGE interface by
-	 * default regardless of the V_ip6_accept_rtadv configuration to
-	 * prevent the interface from accepting RA messages arrived
-	 * on one of the member interfaces with ND6_IFF_ACCEPT_RTADV.
 	 */
-	if (V_ip6_accept_rtadv &&
-	    !(ifp->if_flags & IFF_LOOPBACK) &&
-	    (ifp->if_type != IFT_BRIDGE)) {
+	if (V_ip6_accept_rtadv && !(ifp->if_flags & IFF_LOOPBACK)) {
 			nd->flags |= ND6_IFF_ACCEPT_RTADV;
 			/* If we globally accept rtadv, assume IPv6 on. */
 			nd->flags &= ~ND6_IFF_IFDISABLED;