While flushing the multicast filter of an interface, do not zero the relevant

ifmultiaddr structures' reference to the parent interface, unless the parent
interface is really detaching. While here, program only link layer multicast
filters to a wlan's hardware parent interface.

PR:		kern/142391, kern/142392
Reviewed by:	sam, rpaolo, bms
MFC after:	1 week

1 files changed, 19 insertions, 2 deletions

diff --git a/sys/net/if.c b/sys/net/if.c
index aa04eff..565913d 100644
--- a/sys/net/if.c
+++ b/sys/net/if.c
@@ -740,9 +740,10 @@ if_purgeaddrs(struct ifnet *ifp)
 }
 
 /*
- * Remove any multicast network addresses from an interface.
+ * Remove any multicast network addresses from an interface when an ifnet
+ * is going away.
  */
-void
+static void
 if_purgemaddrs(struct ifnet *ifp)
 {
 	struct ifmultiaddr *ifma;
@@ -2940,6 +2941,22 @@ if_delmulti(struct ifnet *ifp, struct sockaddr *sa)
 }
 
 /*
+ * Delete all multicast group membership for an interface.
+ * Should be used to quickly flush all multicast filters.
+ */
+void
+if_delallmulti(struct ifnet *ifp)
+{
+	struct ifmultiaddr *ifma;
+	struct ifmultiaddr *next;
+
+	IF_ADDR_LOCK(ifp);
+	TAILQ_FOREACH_SAFE(ifma, &ifp->if_multiaddrs, ifma_link, next)
+		if_delmulti_locked(ifp, ifma, 0);
+	IF_ADDR_UNLOCK(ifp);
+}
+
+/*
  * Delete a multicast group membership by group membership pointer.
  * Network-layer protocol domains must use this routine.
  *