Introduce an infrastructure for dismantling vnet instances.

Vnet modules and protocol domains may now register destructor
functions to clean up and release per-module state.  The destructor
mechanisms can be triggered by invoking "vimage -d", or a future
equivalent command which will be provided via the new jail framework.

While this patch introduces numerous placeholder destructor functions,
many of those are currently incomplete, thus leaking memory or (even
worse) failing to stop all running timers.  Many of such issues are
already known and will be incrementaly fixed over the next weeks in
smaller incremental commits.

Apart from introducing new fields in structs ifnet, domain, protosw
and vnet_net, which requires the kernel and modules to be rebuilt, this
change should have no impact on nooptions VIMAGE builds, since vnet
destructors can only be called in VIMAGE kernels.  Moreover,
destructor functions should be in general compiled in only in
options VIMAGE builds, except for kernel modules which can be safely
kldunloaded at run time.

Bump __FreeBSD_version to 800097.
Reviewed by:	bz, julian
Approved by:	rwatson, kib (re), julian (mentor)

1 files changed, 30 insertions, 5 deletions

diff --git a/sys/net/if_loop.c b/sys/net/if_loop.c
index 2bbccac..b0f22c8 100644
--- a/sys/net/if_loop.c
+++ b/sys/net/if_loop.c
@@ -105,6 +105,9 @@ int		looutput(struct ifnet *ifp, struct mbuf *m,
 static int	lo_clone_create(struct if_clone *, int, caddr_t);
 static void	lo_clone_destroy(struct ifnet *);
 static int	vnet_loif_iattach(const void *);
+#ifdef VIMAGE
+static int	vnet_loif_idetach(const void *);
+#endif
 
 #ifdef VIMAGE_GLOBALS
 struct ifnet *loif;			/* Used externally */
@@ -119,7 +122,10 @@ static const vnet_modinfo_t vnet_loif_modinfo = {
 	.vmi_id		= VNET_MOD_LOIF,
 	.vmi_dependson	= VNET_MOD_IF_CLONE,
 	.vmi_name	= "loif",
-	.vmi_iattach	= vnet_loif_iattach
+	.vmi_iattach	= vnet_loif_iattach,
+#ifdef VIMAGE
+	.vmi_idetach	= vnet_loif_idetach
+#endif
 };
 #endif /* !VIMAGE_GLOBALS */
 
@@ -128,12 +134,11 @@ IFC_SIMPLE_DECLARE(lo, 1);
 static void
 lo_clone_destroy(struct ifnet *ifp)
 {
-#ifdef INVARIANTS
-	INIT_VNET_NET(ifp->if_vnet);
-#endif
 
+#ifndef VIMAGE
 	/* XXX: destroying lo0 will lead to panics. */
 	KASSERT(V_loif != ifp, ("%s: destroying lo0", __func__));
+#endif
 
 	bpfdetach(ifp);
 	if_detach(ifp);
@@ -166,7 +171,8 @@ lo_clone_create(struct if_clone *ifc, int unit, caddr_t params)
 	return (0);
 }
 
-static int vnet_loif_iattach(const void *unused __unused)
+static int
+vnet_loif_iattach(const void *unused __unused)
 {
 	INIT_VNET_NET(curvnet);
 
@@ -175,7 +181,11 @@ static int vnet_loif_iattach(const void *unused __unused)
 #ifdef VIMAGE
 	V_lo_cloner = malloc(sizeof(*V_lo_cloner), M_LO_CLONER,
 	    M_WAITOK | M_ZERO);
+	V_lo_cloner_data = malloc(sizeof(*V_lo_cloner_data), M_LO_CLONER,
+	    M_WAITOK | M_ZERO);
 	bcopy(&lo_cloner, V_lo_cloner, sizeof(*V_lo_cloner));
+	bcopy(lo_cloner.ifc_data, V_lo_cloner_data, sizeof(*V_lo_cloner_data));
+	V_lo_cloner->ifc_data = V_lo_cloner_data;
 	if_clone_attach(V_lo_cloner);
 #else
 	if_clone_attach(&lo_cloner);
@@ -183,6 +193,21 @@ static int vnet_loif_iattach(const void *unused __unused)
 	return (0);
 }
 
+#ifdef VIMAGE
+static int
+vnet_loif_idetach(const void *unused __unused)
+{
+	INIT_VNET_NET(curvnet);
+
+	if_clone_detach(V_lo_cloner);
+	free(V_lo_cloner, M_LO_CLONER);
+	free(V_lo_cloner_data, M_LO_CLONER);
+	V_loif = NULL;
+
+	return (0);
+}
+#endif
+
 static int
 loop_modevent(module_t mod, int type, void *data)
 {