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, 25 insertions, 1 deletions

diff --git a/sys/net/if.c b/sys/net/if.c
index 1a5dcd2..35a5e0b 100644
--- a/sys/net/if.c
+++ b/sys/net/if.c
@@ -153,6 +153,9 @@ extern void	nd6_setmtu(struct ifnet *);
 #endif
 
 static int	vnet_net_iattach(const void *);
+#ifdef VIMAGE
+static int	vnet_net_idetach(const void *);
+#endif
 
 #ifdef VIMAGE_GLOBALS
 struct	ifnethead ifnet;	/* depend on static init XXX */
@@ -189,7 +192,10 @@ static const vnet_modinfo_t vnet_net_modinfo = {
 	.vmi_name	= "net",
 	.vmi_size	= sizeof(struct vnet_net),
 	.vmi_symmap	= vnet_net_symmap,
-	.vmi_iattach	= vnet_net_iattach
+	.vmi_iattach	= vnet_net_iattach,
+#ifdef VIMAGE
+	.vmi_idetach	= vnet_net_idetach
+#endif
 };
 #endif /* !VIMAGE_GLOBALS */
 
@@ -446,6 +452,22 @@ vnet_net_iattach(const void *unused __unused)
 	return (0);
 }
 
+#ifdef VIMAGE
+static int
+vnet_net_idetach(const void *unused __unused)
+{
+	INIT_VNET_NET(curvnet);
+
+	VNET_ASSERT(TAILQ_EMPTY(&V_ifnet));
+	VNET_ASSERT(TAILQ_EMPTY(&V_ifg_head));
+	VNET_ASSERT(SLIST_EMPTY(&V_ifklist.kl_list));
+
+	free((caddr_t)V_ifindex_table, M_IFNET);
+
+	return (0);
+}
+#endif
+
 void
 if_grow(void)
 {
@@ -688,6 +710,8 @@ if_attach_internal(struct ifnet *ifp, int vmove)
 
 #ifdef VIMAGE
 	ifp->if_vnet = curvnet;
+	if (ifp->if_home_vnet == NULL)
+		ifp->if_home_vnet = curvnet;
 #endif
 
 	if_addgroup(ifp, IFG_ALL);