bpf: add a crutch to support if_vmove

Fixes:	0bf42a0a05

sys/net/bpf.c

@@ -2722,6 +2722,22 @@ bpf_detach(struct bpf_if *bp)
 	BPF_UNLOCK();
 }
 
+#ifdef VIMAGE
+/*
+ * Move bpf to a different VNET.  This KPI is a crutch to support if_vmove
+ * and is not supposed to be used anywhere else.
+ */
+void
+bpf_vmove(struct bpf_if *bp)
+{
+
+	BPF_LOCK();
+	LIST_REMOVE(bp, bif_next);
+	LIST_INSERT_HEAD(&V_bpf_iflist, bp, bif_next);
+	BPF_UNLOCK();
+}
+#endif
+
 bool
 bpf_peers_present_if(struct ifnet *ifp)
 {

sys/net/bpf.h

@@ -425,6 +425,7 @@ CK_LIST_HEAD(bpfd_list, bpf_d);
 struct bpf_if *	bpf_attach(const char *, u_int, u_int,
 	    const struct bif_methods *, void *);
 void	bpf_detach(struct bpf_if *);
+void	bpf_vmove(struct bpf_if *bp);
 void	bpf_bufheld(struct bpf_d *d);
 int	bpf_validate(const struct bpf_insn *, int);
 void	bpf_tap(struct bpf_if *, u_char *, u_int);

sys/net/if.c

@@ -1285,6 +1285,7 @@ if_vmove(struct ifnet *ifp, struct vnet *new_vnet)
 	 */
 	CURVNET_SET_QUIET(new_vnet);
 	if_attach_internal(ifp, true);
+	bpf_vmove(ifp->if_bpf);
 	CURVNET_RESTORE();
 }