Add destroy_object callback to object rewriting framework.

It is called when last reference to named object is going to be released
and allows to do additional cleanup for implementation of named objects.

Obtained from:	Yandex LLC
Sponsored by:	Yandex LLC

2 files changed, 11 insertions, 2 deletions

diff --git a/sys/netpfil/ipfw/ip_fw_private.h b/sys/netpfil/ipfw/ip_fw_private.h
index b36ca3f..7be3d1e 100644
--- a/sys/netpfil/ipfw/ip_fw_private.h
+++ b/sys/netpfil/ipfw/ip_fw_private.h
@@ -564,7 +564,12 @@ typedef struct named_object *(ipfw_obj_fidx_cb)(struct ip_fw_chain *ch,
  */
 typedef int (ipfw_obj_create_cb)(struct ip_fw_chain *ch, struct tid_info *ti,
     uint16_t *pkidx);
-
+/*
+ * Object destroy callback. Intended to free resources allocated by
+ * create_object callback.
+ */
+typedef void (ipfw_obj_destroy_cb)(struct ip_fw_chain *ch,
+    struct named_object *no);
 
 struct opcode_obj_rewrite {
 	uint32_t		opcode;		/* Opcode to act upon */
@@ -574,6 +579,7 @@ struct opcode_obj_rewrite {
 	ipfw_obj_fname_cb	*find_byname;	/* Find named object by name */
 	ipfw_obj_fidx_cb	*find_bykidx;	/* Find named object by kidx */
 	ipfw_obj_create_cb	*create_object;	/* Create named object */
+	ipfw_obj_destroy_cb	*destroy_object;/* Destroy named object */
 };
 
 #define	IPFW_ADD_OBJ_REWRITER(f, c)	do {	\
diff --git a/sys/netpfil/ipfw/ip_fw_sockopt.c b/sys/netpfil/ipfw/ip_fw_sockopt.c
index e1caa14..070aed3 100644
--- a/sys/netpfil/ipfw/ip_fw_sockopt.c
+++ b/sys/netpfil/ipfw/ip_fw_sockopt.c
@@ -2348,7 +2348,10 @@ unref_rule_objects(struct ip_fw_chain *ch, struct ip_fw *rule)
 		KASSERT(no->refcnt > 0, ("refcount for table %d is %d",
 		    kidx, no->refcnt));
 
-		no->refcnt--;
+		if (no->refcnt == 1 && rw->destroy_object != NULL)
+			rw->destroy_object(ch, no);
+		else
+			no->refcnt--;
 	}
 }