usrloc: Avoid firing DELETE and EXPIRE for same ct

This patch fixes a usrloc callbacks API issue where both the
UL_CONTACT_DELETE and UL_CONTACT_EXPIRE events would often be fired for
the same contact, when the "write-back" SQL mode is in use.

The following modules should notice improved behavior:
    mid_registrar, pua_bla, pua_usrloc, snmpstats

(cherry picked from commit 1a50d66)

modules/usrloc/ucontact.h

@@ -202,14 +202,15 @@ void free_ucontact_coords(ucontact_coords coords);
 int is_my_ucontact(ucontact_t *c);
 
 /*! \brief
- * ancient time used for marking the contacts forced to expired
+ * Non-zero but still ancient time which forces a contact to expire
  */
 #define UL_EXPIRED_TIME 10
+#define FORCE_EXPIRED_CONTACT(c)  ((c)->expires == UL_EXPIRED_TIME)
 
 /*
- * Valid contact is a contact that either didn't expire yet or is permanent
+ * A contact is valid when it is neither expired nor permanent
  */
-#define VALID_CONTACT(c, t)   ((c->expires>t) || (c->expires==0))
+#define VALID_CONTACT(c, t)   ((c)->expires>(t) || (c)->expires==0)
 
 
 /*! \brief

modules/usrloc/urecord.c

@@ -248,8 +248,8 @@ static inline int nodb_timer(urecord_t* _r)
 
 	while(ptr) {
 		if (!VALID_CONTACT(ptr, act_time)) {
-			/* run callbacks for EXPIRE event */
-			if (exists_ulcb_type(UL_CONTACT_EXPIRE))
+			/* for forcibly expired contacts, DELETE event is already run */
+			if (!FORCE_EXPIRED_CONTACT(ptr) && exists_ulcb_type(UL_CONTACT_EXPIRE))
 				run_ul_callbacks( UL_CONTACT_EXPIRE, ptr, NULL);
 
 			LM_DBG("Binding '%.*s','%.*s' has expired\n",
@@ -282,10 +282,9 @@ static inline int ALLOW_UNUSED wt_timer(urecord_t* _r)
 
 	while(ptr) {
 		if (!VALID_CONTACT(ptr, act_time)) {
-			/* run callbacks for EXPIRE event */
-			if (exists_ulcb_type(UL_CONTACT_EXPIRE)) {
+			/* for forcibly expired contacts, DELETE event is already run */
+			if (!FORCE_EXPIRED_CONTACT(ptr) && exists_ulcb_type(UL_CONTACT_EXPIRE))
 				run_ul_callbacks( UL_CONTACT_EXPIRE, ptr, NULL);
-			}
 
 			LM_DBG("Binding '%.*s','%.*s' has expired\n",
 				ptr->aor->len, ZSW(ptr->aor->s),
@@ -325,10 +324,9 @@ static inline int wb_timer(urecord_t* _r,query_list_t **ins_list)
 
 	while(ptr) {
 		if (!VALID_CONTACT(ptr, act_time)) {
-			/* run callbacks for EXPIRE event */
-			if (exists_ulcb_type(UL_CONTACT_EXPIRE)) {
+			/* for forcibly expired contacts, DELETE event is already run */
+			if (!FORCE_EXPIRED_CONTACT(ptr) && exists_ulcb_type(UL_CONTACT_EXPIRE))
 				run_ul_callbacks( UL_CONTACT_EXPIRE, ptr, NULL);
-			}
 
 			LM_DBG("Binding '%.*s','%.*s' has expired\n",
 				ptr->aor->len, ZSW(ptr->aor->s),