Fix group membership of cloned interfaces when one is moved by

if_vmove().

In if_vmove(), if_detach_internal() and if_attach_internal() were
called in series to detach and reattach the interface.  When
detaching, if_delgroup() was called and the interface leaves all of
the group membership.  And then upon attachment, if_addgroup(ifp,
IFG_ALL) was called and it joined only "all" group again.

This had a problem. Normally, a cloned interface automatically joins
a group whose name is ifc_name of the cloner in addition to "all"
upon creation.  However, if_vmove() removed the membership and did
not restore upon attachment.

Differential Revision:	https://reviews.freebsd.org/D1859

1 files changed, 43 insertions, 0 deletions

diff --git a/sys/net/if_clone.c b/sys/net/if_clone.c
index 09f8d2a613bf..dc71bfc04f1e 100644
--- a/sys/net/if_clone.c
+++ b/sys/net/if_clone.c
@@ -518,6 +518,49 @@ done:
 }
 
 /*
+ * if_clone_findifc() looks up ifnet from the current
+ * cloner list, and returns ifc if found.  Note that ifc_refcnt
+ * is incremented.
+ */
+struct if_clone *
+if_clone_findifc(struct ifnet *ifp)
+{
+	struct if_clone *ifc, *ifc0;
+	struct ifnet *ifcifp;
+
+	ifc0 = NULL;
+	IF_CLONERS_LOCK();
+	LIST_FOREACH(ifc, &V_if_cloners, ifc_list) {
+		IF_CLONE_LOCK(ifc);
+		LIST_FOREACH(ifcifp, &ifc->ifc_iflist, if_clones) {
+			if (ifp == ifcifp) {
+				ifc0 = ifc;
+				IF_CLONE_ADDREF_LOCKED(ifc);
+				break;
+			}
+		}
+		IF_CLONE_UNLOCK(ifc);
+		if (ifc0 != NULL)
+			break;
+	}
+	IF_CLONERS_UNLOCK();
+
+	return (ifc0);
+}
+
+/*
+ * if_clone_addgroup() decrements ifc_refcnt because it is called after
+ * if_clone_findifc().
+ */
+void
+if_clone_addgroup(struct ifnet *ifp, struct if_clone *ifc)
+{
+
+	if_addgroup(ifp, ifc->ifc_name);
+	IF_CLONE_REMREF(ifc);
+}
+
+/*
  * A utility function to extract unit numbers from interface names of
  * the form name###.
  *