ofproto: Add a ref_count to "struct rule" to protect it from being freed.
[cascardo/ovs.git] / ofproto / ofproto.c
index a8634aa..5473c7d 100644 (file)
@@ -124,9 +124,7 @@ struct ofoperation {
 
     /* OFOPERATION_MODIFY, OFOPERATION_REPLACE: The old actions, if the actions
      * are changing. */
-    struct ofpact *ofpacts;
-    size_t ofpacts_len;
-    uint32_t meter_id;
+    struct rule_actions *actions;
 
     /* OFOPERATION_DELETE. */
     enum ofp_flow_removed_reason reason; /* Reason flow was removed. */
@@ -190,6 +188,36 @@ static uint32_t rule_eviction_priority(struct rule *);
 static void eviction_group_add_rule(struct rule *);
 static void eviction_group_remove_rule(struct rule *);
 
+/* Criteria that flow_mod and other operations use for selecting rules on
+ * which to operate. */
+struct rule_criteria {
+    /* An OpenFlow table or 255 for all tables. */
+    uint8_t table_id;
+
+    /* OpenFlow matching criteria.  Interpreted different in "loose" way by
+     * collect_rules_loose() and "strict" way by collect_rules_strict(), as
+     * defined in the OpenFlow spec. */
+    struct cls_rule cr;
+
+    /* Matching criteria for the OpenFlow cookie.  Consider a bit B in a rule's
+     * cookie and the corresponding bits C in 'cookie' and M in 'cookie_mask'.
+     * The rule will not be selected if M is 1 and B != C.  */
+    ovs_be64 cookie;
+    ovs_be64 cookie_mask;
+
+    /* Selection based on actions within a rule:
+     *
+     * If out_port != OFPP_ANY, selects only rules that output to out_port. */
+    ofp_port_t out_port;
+};
+
+static void rule_criteria_init(struct rule_criteria *, uint8_t table_id,
+                               const struct match *match,
+                               unsigned int priority,
+                               ovs_be64 cookie, ovs_be64 cookie_mask,
+                               ofp_port_t out_port);
+static void rule_criteria_destroy(struct rule_criteria *);
+
 /* ofport. */
 static void ofport_destroy__(struct ofport *);
 static void ofport_destroy(struct ofport *);
@@ -199,7 +227,6 @@ static int init_ports(struct ofproto *);
 static void reinit_ports(struct ofproto *);
 
 /* rule. */
-static void ofproto_rule_destroy(struct rule *);
 static void ofproto_rule_destroy__(struct rule *);
 static void ofproto_rule_send_removed(struct rule *, uint8_t reason);
 static bool rule_is_modifiable(const struct rule *);
@@ -210,7 +237,8 @@ static enum ofperr add_flow(struct ofproto *, struct ofconn *,
                             const struct ofp_header *);
 static enum ofperr modify_flows__(struct ofproto *, struct ofconn *,
                                   struct ofputil_flow_mod *,
-                                  const struct ofp_header *, struct list *);
+                                  const struct ofp_header *,
+                                  const struct rule_collection *);
 static void delete_flow__(struct rule *rule, struct ofopgroup *,
                           enum ofp_flow_removed_reason)
     OVS_RELEASES(rule->rwlock);
@@ -639,14 +667,15 @@ ofproto_set_mac_table_config(struct ofproto *ofproto, unsigned idle_time,
 }
 
 /* Sets number of upcall handler threads.  The default is
- * (number of online cores - 1). */
+ * (number of online cores - 2). */
 void
 ofproto_set_n_handler_threads(unsigned limit)
 {
     if (limit) {
         n_handler_threads = limit;
     } else {
-        n_handler_threads = MAX(1, sysconf(_SC_NPROCESSORS_ONLN) - 1);
+        int n_proc = sysconf(_SC_NPROCESSORS_ONLN);
+        n_handler_threads = n_proc > 2 ? n_proc - 2 : 1;
     }
 }
 
@@ -1078,10 +1107,20 @@ ofproto_get_snoops(const struct ofproto *ofproto, struct sset *snoops)
 
 /* Deletes 'rule' from 'cls' within 'ofproto'.
  *
+ * Within an ofproto implementation, this function allows an ofproto
+ * implementation to destroy any rules that remain when its ->destruct()
+ * function is called.  This function is not suitable for use elsewhere in an
+ * ofproto implementation.
+ *
+ * This function is also used internally in ofproto.c.
+ *
+ * This function implements steps 4.4 and 4.5 in the section titled "Rule Life
+ * Cycle" in ofproto-provider.h.
+
  * The 'cls' argument is redundant (it is &ofproto->tables[rule->table_id].cls)
  * but it allows Clang to do better checking. */
-static void
-ofproto_delete_rule(struct ofproto *ofproto, struct classifier *cls,
+void
+ofproto_rule_delete(struct ofproto *ofproto, struct classifier *cls,
                     struct rule *rule)
     OVS_REQ_WRLOCK(cls->rwlock)
 {
@@ -1119,7 +1158,7 @@ ofproto_flush__(struct ofproto *ofproto)
         cls_cursor_init(&cursor, &table->cls, NULL);
         CLS_CURSOR_FOR_EACH_SAFE (rule, next_rule, cr, &cursor) {
             if (!rule->pending) {
-                ofproto_delete_rule(ofproto, &table->cls, rule);
+                ofproto_rule_delete(ofproto, &table->cls, rule);
             }
         }
         ovs_rwlock_unlock(&table->cls.rwlock);
@@ -1134,11 +1173,6 @@ ofproto_destroy__(struct ofproto *ofproto)
     ovs_assert(list_is_empty(&ofproto->pending));
     ovs_assert(!ofproto->n_pending);
 
-    if (ofproto->meters) {
-        meter_delete(ofproto, 1, ofproto->meter_features.max_meters);
-        free(ofproto->meters);
-    }
-
     connmgr_destroy(ofproto->connmgr);
 
     hmap_remove(&all_ofprotos, &ofproto->hmap_node);
@@ -1176,6 +1210,13 @@ ofproto_destroy(struct ofproto *p)
         return;
     }
 
+    if (p->meters) {
+        meter_delete(p, 1, p->meter_features.max_meters);
+        p->meter_features.max_meters = 0;
+        free(p->meters);
+        p->meters = NULL;
+    }
+
     ofproto_flush__(p);
     HMAP_FOR_EACH_SAFE (ofport, next_ofport, hmap_node, &p->ports) {
         ofport_destroy(ofport);
@@ -1281,7 +1322,6 @@ ofproto_run(struct ofproto *p)
             struct oftable *table = &p->tables[i];
             struct eviction_group *evg;
             struct cls_cursor cursor;
-            struct cls_rule cr;
             struct rule *rule;
 
             if (!table->eviction_fields) {
@@ -1293,7 +1333,7 @@ ofproto_run(struct ofproto *p)
             }
 
             ovs_rwlock_rdlock(&table->cls.rwlock);
-            cls_cursor_init(&cursor, &table->cls, &cr);
+            cls_cursor_init(&cursor, &table->cls, NULL);
             CLS_CURSOR_FOR_EACH (rule, cr, &cursor) {
                 if (!rule->eviction_group
                     && (rule->idle_timeout || rule->hard_timeout)) {
@@ -1678,6 +1718,32 @@ ofproto_port_del(struct ofproto *ofproto, ofp_port_t ofp_port)
     return error;
 }
 
+static int
+simple_flow_mod(struct ofproto *ofproto,
+                const struct match *match, unsigned int priority,
+                const struct ofpact *ofpacts, size_t ofpacts_len,
+                enum ofp_flow_mod_command command)
+{
+    struct ofputil_flow_mod fm;
+
+    memset(&fm, 0, sizeof fm);
+    fm.match = *match;
+    fm.priority = priority;
+    fm.cookie = 0;
+    fm.new_cookie = 0;
+    fm.modify_cookie = false;
+    fm.table_id = 0;
+    fm.command = command;
+    fm.idle_timeout = 0;
+    fm.hard_timeout = 0;
+    fm.buffer_id = UINT32_MAX;
+    fm.out_port = OFPP_ANY;
+    fm.flags = 0;
+    fm.ofpacts = CONST_CAST(struct ofpact *, ofpacts);
+    fm.ofpacts_len = ofpacts_len;
+    return handle_flow_mod__(ofproto, NULL, &fm, NULL);
+}
+
 /* Adds a flow to OpenFlow flow table 0 in 'p' that matches 'cls_rule' and
  * performs the 'n_actions' actions in 'actions'.  The new flow will not
  * timeout.
@@ -1695,23 +1761,31 @@ ofproto_add_flow(struct ofproto *ofproto, const struct match *match,
                  const struct ofpact *ofpacts, size_t ofpacts_len)
 {
     const struct rule *rule;
+    bool must_add;
 
+    /* First do a cheap check whether the rule we're looking for already exists
+     * with the actions that we want.  If it does, then we're done. */
     ovs_rwlock_rdlock(&ofproto->tables[0].cls.rwlock);
     rule = rule_from_cls_rule(classifier_find_match_exactly(
                                   &ofproto->tables[0].cls, match, priority));
+    if (rule) {
+        ovs_rwlock_rdlock(&rule->rwlock);
+        must_add = !ofpacts_equal(rule->actions->ofpacts,
+                                  rule->actions->ofpacts_len,
+                                  ofpacts, ofpacts_len);
+        ovs_rwlock_unlock(&rule->rwlock);
+    } else {
+        must_add = true;
+    }
     ovs_rwlock_unlock(&ofproto->tables[0].cls.rwlock);
-    if (!rule || !ofpacts_equal(rule->ofpacts, rule->ofpacts_len,
-                                ofpacts, ofpacts_len)) {
-        struct ofputil_flow_mod fm;
 
-        memset(&fm, 0, sizeof fm);
-        fm.match = *match;
-        fm.priority = priority;
-        fm.buffer_id = UINT32_MAX;
-        fm.ofpacts = xmemdup(ofpacts, ofpacts_len);
-        fm.ofpacts_len = ofpacts_len;
-        add_flow(ofproto, NULL, &fm, NULL);
-        free(fm.ofpacts);
+    /* If there's no such rule or the rule doesn't have the actions we want,
+     * fall back to a executing a full flow mod.  We can't optimize this at
+     * all because we didn't take enough locks above to ensure that the flow
+     * table didn't already change beneath us.  */
+    if (must_add) {
+        simple_flow_mod(ofproto, match, priority, ofpacts, ofpacts_len,
+                        OFPFC_MODIFY_STRICT);
     }
 }
 
@@ -1737,26 +1811,21 @@ ofproto_delete_flow(struct ofproto *ofproto,
     struct classifier *cls = &ofproto->tables[0].cls;
     struct rule *rule;
 
+    /* First do a cheap check whether the rule we're looking for has already
+     * been deleted.  If so, then we're done. */
     ovs_rwlock_rdlock(&cls->rwlock);
     rule = rule_from_cls_rule(classifier_find_match_exactly(cls, target,
                                                             priority));
     ovs_rwlock_unlock(&cls->rwlock);
     if (!rule) {
-        /* No such rule -> success. */
-        return true;
-    } else if (rule->pending) {
-        /* An operation on the rule is already pending -> failure.
-         * Caller must retry later if it's important. */
-        return false;
-    } else {
-        /* Initiate deletion -> success. */
-        ovs_rwlock_wrlock(&cls->rwlock);
-        ofproto_delete_rule(ofproto, cls, rule);
-        ovs_rwlock_unlock(&cls->rwlock);
-
         return true;
     }
 
+    /* Fall back to a executing a full flow mod.  We can't optimize this at all
+     * because we didn't take enough locks above to ensure that the flow table
+     * didn't already change beneath us.  */
+    return simple_flow_mod(ofproto, target, priority, NULL, 0,
+                           OFPFC_DELETE_STRICT) != OFPROTO_POSTPONE;
 }
 
 /* Starts the process of deleting all of the flows from all of ofproto's flow
@@ -2247,12 +2316,30 @@ update_mtu(struct ofproto *p, struct ofport *port)
     }
 }
 \f
-static void
-ofproto_rule_destroy(struct rule *rule)
+void
+ofproto_rule_ref(struct rule *rule)
 {
     if (rule) {
-        rule->ofproto->ofproto_class->rule_destruct(rule);
-        ofproto_rule_destroy__(rule);
+        unsigned int orig;
+
+        atomic_add(&rule->ref_count, 1, &orig);
+        ovs_assert(orig != 0);
+    }
+}
+
+void
+ofproto_rule_unref(struct rule *rule)
+{
+    if (rule) {
+        unsigned int orig;
+
+        atomic_sub(&rule->ref_count, 1, &orig);
+        if (orig == 1) {
+            rule->ofproto->ofproto_class->rule_destruct(rule);
+            ofproto_rule_destroy__(rule);
+        } else {
+            ovs_assert(orig != 0);
+        }
     }
 }
 
@@ -2260,25 +2347,54 @@ static void
 ofproto_rule_destroy__(struct rule *rule)
 {
     cls_rule_destroy(&rule->cr);
-    free(rule->ofpacts);
+    rule_actions_unref(rule->actions);
     ovs_mutex_destroy(&rule->timeout_mutex);
     ovs_rwlock_destroy(&rule->rwlock);
     rule->ofproto->ofproto_class->rule_dealloc(rule);
 }
 
-/* This function allows an ofproto implementation to destroy any rules that
- * remain when its ->destruct() function is called..  This function implements
- * steps 4.4 and 4.5 in the section titled "Rule Life Cycle" in
- * ofproto-provider.h.
- *
- * This function should only be called from an ofproto implementation's
- * ->destruct() function.  It is not suitable elsewhere. */
+/* Creates and returns a new 'struct rule_actions', with a ref_count of 1,
+ * whose actions are a copy of from the 'ofpacts_len' bytes of 'ofpacts'. */
+struct rule_actions *
+rule_actions_create(const struct ofpact *ofpacts, size_t ofpacts_len)
+{
+    struct rule_actions *actions;
+
+    actions = xmalloc(sizeof *actions);
+    atomic_init(&actions->ref_count, 1);
+    actions->ofpacts = xmemdup(ofpacts, ofpacts_len);
+    actions->ofpacts_len = ofpacts_len;
+    actions->meter_id = ofpacts_get_meter(ofpacts, ofpacts_len);
+    return actions;
+}
+
+/* Increments 'actions''s ref_count. */
 void
-ofproto_rule_delete(struct ofproto *ofproto, struct classifier *cls,
-                    struct rule *rule)
-    OVS_REQ_WRLOCK(cls->rwlock)
+rule_actions_ref(struct rule_actions *actions)
+{
+    if (actions) {
+        unsigned int orig;
+
+        atomic_add(&actions->ref_count, 1, &orig);
+        ovs_assert(orig != 0);
+    }
+}
+
+/* Decrements 'actions''s ref_count and frees 'actions' if the ref_count
+ * reaches 0. */
+void
+rule_actions_unref(struct rule_actions *actions)
 {
-    ofproto_delete_rule(ofproto, cls, rule);
+    if (actions) {
+        unsigned int orig;
+
+        atomic_sub(&actions->ref_count, 1, &orig);
+        if (orig == 1) {
+            free(actions);
+        } else {
+            ovs_assert(orig != 0);
+        }
+    }
 }
 
 /* Returns true if 'rule' has an OpenFlow OFPAT_OUTPUT or OFPAT_ENQUEUE action
@@ -2287,7 +2403,8 @@ bool
 ofproto_rule_has_out_port(const struct rule *rule, ofp_port_t port)
 {
     return (port == OFPP_ANY
-            || ofpacts_output_to_port(rule->ofpacts, rule->ofpacts_len, port));
+            || ofpacts_output_to_port(rule->actions->ofpacts,
+                                      rule->actions->ofpacts_len, port));
 }
 
 /* Returns true if a rule related to 'op' has an OpenFlow OFPAT_OUTPUT or
@@ -2306,7 +2423,8 @@ ofoperation_has_out_port(const struct ofoperation *op, ofp_port_t out_port)
 
     case OFOPERATION_MODIFY:
     case OFOPERATION_REPLACE:
-        return ofpacts_output_to_port(op->ofpacts, op->ofpacts_len, out_port);
+        return ofpacts_output_to_port(op->actions->ofpacts,
+                                      op->actions->ofpacts_len, out_port);
     }
 
     NOT_REACHED();
@@ -2478,30 +2596,6 @@ reject_slave_controller(struct ofconn *ofconn)
     }
 }
 
-/* Finds the OFPACT_METER action, if any, in the 'ofpacts_len' bytes of
- * 'ofpacts'.  If found, returns its meter ID; if not, returns 0.
- *
- * This function relies on the order of 'ofpacts' being correct (as checked by
- * ofpacts_verify()). */
-static uint32_t
-find_meter(const struct ofpact ofpacts[], size_t ofpacts_len)
-{
-    const struct ofpact *a;
-
-    OFPACT_FOR_EACH (a, ofpacts, ofpacts_len) {
-        enum ovs_instruction_type inst;
-
-        inst = ovs_instruction_type_from_ofpact_type(a->type);
-        if (a->type == OFPACT_METER) {
-            return ofpact_get_METER(a)->meter_id;
-        } else if (inst > OVSINST_OFPIT13_METER) {
-            break;
-        }
-    }
-
-    return 0;
-}
-
 /* Checks that the 'ofpacts_len' bytes of actions in 'ofpacts' are appropriate
  * for a packet with the prerequisites satisfied by 'flow' in table 'table_id'.
  * 'flow' may be temporarily modified, but is restored at return.
@@ -2520,7 +2614,7 @@ ofproto_check_ofpacts(struct ofproto *ofproto,
         return error;
     }
 
-    mid = find_meter(ofpacts, ofpacts_len);
+    mid = ofpacts_get_meter(ofpacts, ofpacts_len);
     if (mid && ofproto_get_provider_meter_id(ofproto, mid) == UINT32_MAX) {
         return OFPERR_OFPMMFC_INVALID_METER;
     }
@@ -2918,163 +3012,203 @@ next_matching_table(const struct ofproto *ofproto,
          (TABLE) != NULL;                                         \
          (TABLE) = next_matching_table(OFPROTO, TABLE, TABLE_ID))
 
-/* Searches 'ofproto' for rules in table 'table_id' (or in all tables, if
- * 'table_id' is 0xff) that match 'match' in the "loose" way required for
- * OpenFlow OFPFC_MODIFY and OFPFC_DELETE requests and puts them on list
- * 'rules'.
+/* Initializes 'criteria' in a straightforward way based on the other
+ * parameters.
  *
- * If 'out_port' is anything other than OFPP_ANY, then only rules that output
- * to 'out_port' are included.
+ * For "loose" matching, the 'priority' parameter is unimportant and may be
+ * supplied as 0. */
+static void
+rule_criteria_init(struct rule_criteria *criteria, uint8_t table_id,
+                   const struct match *match, unsigned int priority,
+                   ovs_be64 cookie, ovs_be64 cookie_mask,
+                   ofp_port_t out_port)
+{
+    criteria->table_id = table_id;
+    cls_rule_init(&criteria->cr, match, priority);
+    criteria->cookie = cookie;
+    criteria->cookie_mask = cookie_mask;
+    criteria->out_port = out_port;
+}
+
+static void
+rule_criteria_destroy(struct rule_criteria *criteria)
+{
+    cls_rule_destroy(&criteria->cr);
+}
+
+void
+rule_collection_init(struct rule_collection *rules)
+{
+    rules->rules = rules->stub;
+    rules->n = 0;
+    rules->capacity = ARRAY_SIZE(rules->stub);
+}
+
+void
+rule_collection_add(struct rule_collection *rules, struct rule *rule)
+{
+    if (rules->n >= rules->capacity) {
+        size_t old_size, new_size;
+
+        old_size = rules->capacity * sizeof *rules->rules;
+        rules->capacity *= 2;
+        new_size = rules->capacity * sizeof *rules->rules;
+
+        if (rules->rules == rules->stub) {
+            rules->rules = xmalloc(new_size);
+            memcpy(rules->rules, rules->stub, old_size);
+        } else {
+            rules->rules = xrealloc(rules->rules, new_size);
+        }
+    }
+
+    rules->rules[rules->n++] = rule;
+}
+
+void
+rule_collection_destroy(struct rule_collection *rules)
+{
+    if (rules->rules != rules->stub) {
+        free(rules->rules);
+    }
+}
+
+static enum ofperr
+collect_rule(struct rule *rule, const struct rule_criteria *c,
+             struct rule_collection *rules)
+{
+    if (ofproto_rule_is_hidden(rule)) {
+        return 0;
+    } else if (rule->pending) {
+        return OFPROTO_POSTPONE;
+    } else {
+        if ((c->table_id == rule->table_id || c->table_id == 0xff)
+            && ofproto_rule_has_out_port(rule, c->out_port)
+            && !((rule->flow_cookie ^ c->cookie) & c->cookie_mask)) {
+            rule_collection_add(rules, rule);
+        }
+        return 0;
+    }
+}
+
+/* Searches 'ofproto' for rules that match the criteria in 'criteria'.  Matches
+ * on classifiers rules are done in the "loose" way required for OpenFlow
+ * OFPFC_MODIFY and OFPFC_DELETE requests.  Puts the selected rules on list
+ * 'rules'.
  *
  * Hidden rules are always omitted.
  *
  * Returns 0 on success, otherwise an OpenFlow error code. */
 static enum ofperr
-collect_rules_loose(struct ofproto *ofproto, uint8_t table_id,
-                    const struct match *match,
-                    ovs_be64 cookie, ovs_be64 cookie_mask,
-                    ofp_port_t out_port, struct list *rules)
+collect_rules_loose(struct ofproto *ofproto,
+                    const struct rule_criteria *criteria,
+                    struct rule_collection *rules)
 {
     struct oftable *table;
-    struct cls_rule cr;
     enum ofperr error;
 
-    error = check_table_id(ofproto, table_id);
+    rule_collection_init(rules);
+
+    error = check_table_id(ofproto, criteria->table_id);
     if (error) {
-        return error;
+        goto exit;
     }
 
-    list_init(rules);
-    cls_rule_init(&cr, match, 0);
-
-    if (cookie_mask == htonll(UINT64_MAX)) {
+    if (criteria->cookie_mask == htonll(UINT64_MAX)) {
         struct rule *rule;
 
-        HINDEX_FOR_EACH_WITH_HASH (rule, cookie_node, hash_cookie(cookie),
+        HINDEX_FOR_EACH_WITH_HASH (rule, cookie_node,
+                                   hash_cookie(criteria->cookie),
                                    &ofproto->cookies) {
-            if (table_id != rule->table_id && table_id != 0xff) {
-                continue;
-            }
-            if (ofproto_rule_is_hidden(rule)) {
-                continue;
-            }
-            if (cls_rule_is_loose_match(&rule->cr, &cr.match)) {
-                if (rule->pending) {
-                    error = OFPROTO_POSTPONE;
-                    goto exit;
-                }
-                if (rule->flow_cookie == cookie /* Hash collisions possible. */
-                    && ofproto_rule_has_out_port(rule, out_port)) {
-                    list_push_back(rules, &rule->ofproto_node);
+            if (cls_rule_is_loose_match(&rule->cr, &criteria->cr.match)) {
+                error = collect_rule(rule, criteria, rules);
+                if (error) {
+                    break;
                 }
             }
         }
-        goto exit;
-    }
-
-    FOR_EACH_MATCHING_TABLE (table, table_id, ofproto) {
-        struct cls_cursor cursor;
-        struct rule *rule;
+    } else {
+        FOR_EACH_MATCHING_TABLE (table, criteria->table_id, ofproto) {
+            struct cls_cursor cursor;
+            struct rule *rule;
 
-        ovs_rwlock_rdlock(&table->cls.rwlock);
-        cls_cursor_init(&cursor, &table->cls, &cr);
-        CLS_CURSOR_FOR_EACH (rule, cr, &cursor) {
-            if (rule->pending) {
-                ovs_rwlock_unlock(&table->cls.rwlock);
-                error = OFPROTO_POSTPONE;
-                goto exit;
-            }
-            if (!ofproto_rule_is_hidden(rule)
-                && ofproto_rule_has_out_port(rule, out_port)
-                    && !((rule->flow_cookie ^ cookie) & cookie_mask)) {
-                list_push_back(rules, &rule->ofproto_node);
+            ovs_rwlock_rdlock(&table->cls.rwlock);
+            cls_cursor_init(&cursor, &table->cls, &criteria->cr);
+            CLS_CURSOR_FOR_EACH (rule, cr, &cursor) {
+                error = collect_rule(rule, criteria, rules);
+                if (error) {
+                    break;
+                }
             }
+            ovs_rwlock_unlock(&table->cls.rwlock);
         }
-        ovs_rwlock_unlock(&table->cls.rwlock);
     }
 
 exit:
-    cls_rule_destroy(&cr);
+    if (error) {
+        rule_collection_destroy(rules);
+    }
     return error;
 }
 
-/* Searches 'ofproto' for rules in table 'table_id' (or in all tables, if
- * 'table_id' is 0xff) that match 'match' in the "strict" way required for
- * OpenFlow OFPFC_MODIFY_STRICT and OFPFC_DELETE_STRICT requests and puts them
- * on list 'rules'.
- *
- * If 'out_port' is anything other than OFPP_ANY, then only rules that output
- * to 'out_port' are included.
+/* Searches 'ofproto' for rules that match the criteria in 'criteria'.  Matches
+ * on classifiers rules are done in the "strict" way required for OpenFlow
+ * OFPFC_MODIFY_STRICT and OFPFC_DELETE_STRICT requests.  Puts the selected
+ * rules on list 'rules'.
  *
  * Hidden rules are always omitted.
  *
  * Returns 0 on success, otherwise an OpenFlow error code. */
 static enum ofperr
-collect_rules_strict(struct ofproto *ofproto, uint8_t table_id,
-                     const struct match *match, unsigned int priority,
-                     ovs_be64 cookie, ovs_be64 cookie_mask,
-                     ofp_port_t out_port, struct list *rules)
+collect_rules_strict(struct ofproto *ofproto,
+                     const struct rule_criteria *criteria,
+                     struct rule_collection *rules)
 {
     struct oftable *table;
-    struct cls_rule cr;
     int error;
 
-    error = check_table_id(ofproto, table_id);
+    rule_collection_init(rules);
+
+    error = check_table_id(ofproto, criteria->table_id);
     if (error) {
-        return error;
+        goto exit;
     }
 
-    list_init(rules);
-    cls_rule_init(&cr, match, priority);
-
-    if (cookie_mask == htonll(UINT64_MAX)) {
+    if (criteria->cookie_mask == htonll(UINT64_MAX)) {
         struct rule *rule;
 
-        HINDEX_FOR_EACH_WITH_HASH (rule, cookie_node, hash_cookie(cookie),
+        HINDEX_FOR_EACH_WITH_HASH (rule, cookie_node,
+                                   hash_cookie(criteria->cookie),
                                    &ofproto->cookies) {
-            if (table_id != rule->table_id && table_id != 0xff) {
-                continue;
-            }
-            if (ofproto_rule_is_hidden(rule)) {
-                continue;
-            }
-            if (cls_rule_equal(&rule->cr, &cr)) {
-                if (rule->pending) {
-                    error = OFPROTO_POSTPONE;
-                    goto exit;
-                }
-                if (rule->flow_cookie == cookie /* Hash collisions possible. */
-                    && ofproto_rule_has_out_port(rule, out_port)) {
-                    list_push_back(rules, &rule->ofproto_node);
+            if (cls_rule_equal(&rule->cr, &criteria->cr)) {
+                error = collect_rule(rule, criteria, rules);
+                if (error) {
+                    break;
                 }
             }
         }
-        goto exit;
-    }
-
-    FOR_EACH_MATCHING_TABLE (table, table_id, ofproto) {
-        struct rule *rule;
+    } else {
+        FOR_EACH_MATCHING_TABLE (table, criteria->table_id, ofproto) {
+            struct rule *rule;
 
-        ovs_rwlock_rdlock(&table->cls.rwlock);
-        rule = rule_from_cls_rule(classifier_find_rule_exactly(&table->cls,
-                                                               &cr));
-        ovs_rwlock_unlock(&table->cls.rwlock);
-        if (rule) {
-            if (rule->pending) {
-                error = OFPROTO_POSTPONE;
-                goto exit;
-            }
-            if (!ofproto_rule_is_hidden(rule)
-                && ofproto_rule_has_out_port(rule, out_port)
-                    && !((rule->flow_cookie ^ cookie) & cookie_mask)) {
-                list_push_back(rules, &rule->ofproto_node);
+            ovs_rwlock_rdlock(&table->cls.rwlock);
+            rule = rule_from_cls_rule(classifier_find_rule_exactly(
+                                          &table->cls, &criteria->cr));
+            ovs_rwlock_unlock(&table->cls.rwlock);
+            if (rule) {
+                error = collect_rule(rule, criteria, rules);
+                if (error) {
+                    break;
+                }
             }
         }
     }
 
 exit:
-    cls_rule_destroy(&cr);
-    return 0;
+    if (error) {
+        rule_collection_destroy(rules);
+    }
+    return error;
 }
 
 /* Returns 'age_ms' (a duration in milliseconds), converted to seconds and
@@ -3093,25 +3227,28 @@ handle_flow_stats_request(struct ofconn *ofconn,
 {
     struct ofproto *ofproto = ofconn_get_ofproto(ofconn);
     struct ofputil_flow_stats_request fsr;
+    struct rule_criteria criteria;
+    struct rule_collection rules;
     struct list replies;
-    struct list rules;
-    struct rule *rule;
     enum ofperr error;
+    size_t i;
 
     error = ofputil_decode_flow_stats_request(&fsr, request);
     if (error) {
         return error;
     }
 
-    error = collect_rules_loose(ofproto, fsr.table_id, &fsr.match,
-                                fsr.cookie, fsr.cookie_mask,
-                                fsr.out_port, &rules);
+    rule_criteria_init(&criteria, fsr.table_id, &fsr.match, 0, fsr.cookie,
+                       fsr.cookie_mask, fsr.out_port);
+    error = collect_rules_loose(ofproto, &criteria, &rules);
+    rule_criteria_destroy(&criteria);
     if (error) {
         return error;
     }
 
     ofpmp_init(&replies, request);
-    LIST_FOR_EACH (rule, ofproto_node, &rules) {
+    for (i = 0; i < rules.n; i++) {
+        struct rule *rule = rules.rules[i];
         long long int now = time_msec();
         struct ofputil_flow_stats fs;
 
@@ -3124,8 +3261,8 @@ handle_flow_stats_request(struct ofconn *ofconn,
         fs.hard_age = age_secs(now - rule->modified);
         ofproto->ofproto_class->rule_get_stats(rule, &fs.packet_count,
                                                &fs.byte_count);
-        fs.ofpacts = rule->ofpacts;
-        fs.ofpacts_len = rule->ofpacts_len;
+        fs.ofpacts = rule->actions->ofpacts;
+        fs.ofpacts_len = rule->actions->ofpacts_len;
 
         ovs_mutex_lock(&rule->timeout_mutex);
         fs.idle_timeout = rule->idle_timeout;
@@ -3140,6 +3277,8 @@ handle_flow_stats_request(struct ofconn *ofconn,
         }
         ofputil_append_flow_stats_reply(&fs, &replies);
     }
+    rule_collection_destroy(&rules);
+
     ofconn_send_replies(ofconn, &replies);
 
     return 0;
@@ -3163,7 +3302,8 @@ flow_stats_ds(struct rule *rule, struct ds *results)
     ds_put_format(results, "n_bytes=%"PRIu64", ", byte_count);
     cls_rule_format(&rule->cr, results);
     ds_put_char(results, ',');
-    ofpacts_format(rule->ofpacts, rule->ofpacts_len, results);
+    ofpacts_format(rule->actions->ofpacts, rule->actions->ofpacts_len,
+                   results);
     ds_put_cstr(results, "\n");
 }
 
@@ -3220,26 +3360,30 @@ handle_aggregate_stats_request(struct ofconn *ofconn,
     struct ofputil_flow_stats_request request;
     struct ofputil_aggregate_stats stats;
     bool unknown_packets, unknown_bytes;
+    struct rule_criteria criteria;
+    struct rule_collection rules;
     struct ofpbuf *reply;
-    struct list rules;
-    struct rule *rule;
     enum ofperr error;
+    size_t i;
 
     error = ofputil_decode_flow_stats_request(&request, oh);
     if (error) {
         return error;
     }
 
-    error = collect_rules_loose(ofproto, request.table_id, &request.match,
-                                request.cookie, request.cookie_mask,
-                                request.out_port, &rules);
+    rule_criteria_init(&criteria, request.table_id, &request.match, 0,
+                       request.cookie, request.cookie_mask,
+                       request.out_port);
+    error = collect_rules_loose(ofproto, &criteria, &rules);
+    rule_criteria_destroy(&criteria);
     if (error) {
         return error;
     }
 
     memset(&stats, 0, sizeof stats);
     unknown_packets = unknown_bytes = false;
-    LIST_FOR_EACH (rule, ofproto_node, &rules) {
+    for (i = 0; i < rules.n; i++) {
+        struct rule *rule = rules.rules[i];
         uint64_t packet_count;
         uint64_t byte_count;
 
@@ -3267,6 +3411,8 @@ handle_aggregate_stats_request(struct ofconn *ofconn,
         stats.byte_count = UINT64_MAX;
     }
 
+    rule_collection_destroy(&rules);
+
     reply = ofputil_encode_aggregate_stats_reply(&stats, oh);
     ofconn_send_reply(ofconn, reply);
 
@@ -3427,8 +3573,7 @@ evict_rule_from_table(struct ofproto *ofproto, struct oftable *table)
  * error code on failure, or OFPROTO_POSTPONE if the operation cannot be
  * initiated now but may be retried later.
  *
- * Upon successful return, takes ownership of 'fm->ofpacts'.  On failure,
- * ownership remains with the caller.
+ * The caller retains ownership of 'fm->ofpacts'.
  *
  * 'ofconn' is used to retrieve the packet buffer specified in ofm->buffer_id,
  * if any. */
@@ -3486,12 +3631,15 @@ add_flow(struct ofproto *ofproto, struct ofconn *ofconn,
         } else if (rule->pending) {
             return OFPROTO_POSTPONE;
         } else {
-            struct list rules;
+            struct rule_collection rules;
 
-            list_init(&rules);
-            list_push_back(&rules, &rule->ofproto_node);
+            rule_collection_init(&rules);
+            rule_collection_add(&rules, rule);
             fm->modify_cookie = true;
-            return modify_flows__(ofproto, ofconn, fm, request, &rules);
+            error = modify_flows__(ofproto, ofconn, fm, request, &rules);
+            rule_collection_destroy(&rules);
+
+            return error;
         }
     }
 
@@ -3542,6 +3690,7 @@ add_flow(struct ofproto *ofproto, struct ofconn *ofconn,
     /* Initialize base state. */
     rule->ofproto = ofproto;
     cls_rule_move(&rule->cr, &cr);
+    atomic_init(&rule->ref_count, 1);
     rule->pending = NULL;
     rule->flow_cookie = fm->new_cookie;
     rule->created = rule->modified = rule->used = time_msec();
@@ -3554,9 +3703,7 @@ add_flow(struct ofproto *ofproto, struct ofconn *ofconn,
 
     rule->table_id = table - ofproto->tables;
     rule->send_flow_removed = (fm->flags & OFPUTIL_FF_SEND_FLOW_REM) != 0;
-    rule->ofpacts = xmemdup(fm->ofpacts, fm->ofpacts_len);
-    rule->ofpacts_len = fm->ofpacts_len;
-    rule->meter_id = find_meter(rule->ofpacts, rule->ofpacts_len);
+    rule->actions = rule_actions_create(fm->ofpacts, fm->ofpacts_len);
     list_init(&rule->meter_list_node);
     rule->eviction_group = NULL;
     list_init(&rule->expirable);
@@ -3595,17 +3742,18 @@ add_flow(struct ofproto *ofproto, struct ofconn *ofconn,
 static enum ofperr
 modify_flows__(struct ofproto *ofproto, struct ofconn *ofconn,
                struct ofputil_flow_mod *fm, const struct ofp_header *request,
-               struct list *rules)
+               const struct rule_collection *rules)
 {
     enum ofoperation_type type;
     struct ofopgroup *group;
-    struct rule *rule;
     enum ofperr error;
+    size_t i;
 
     type = fm->command == OFPFC_ADD ? OFOPERATION_REPLACE : OFOPERATION_MODIFY;
     group = ofopgroup_create(ofproto, ofconn, request, fm->buffer_id);
     error = OFPERR_OFPBRC_EPERM;
-    LIST_FOR_EACH (rule, ofproto_node, rules) {
+    for (i = 0; i < rules->n; i++) {
+        struct rule *rule = rules->rules[i];
         struct ofoperation *op;
         bool actions_changed;
         bool reset_counters;
@@ -3627,7 +3775,8 @@ modify_flows__(struct ofproto *ofproto, struct ofconn *ofconn,
         }
 
         actions_changed = !ofpacts_equal(fm->ofpacts, fm->ofpacts_len,
-                                         rule->ofpacts, rule->ofpacts_len);
+                                         rule->actions->ofpacts,
+                                         rule->actions->ofpacts_len);
 
         op = ofoperation_create(group, rule, type, 0);
 
@@ -3654,16 +3803,15 @@ modify_flows__(struct ofproto *ofproto, struct ofconn *ofconn,
 
         reset_counters = (fm->flags & OFPUTIL_FF_RESET_COUNTS) != 0;
         if (actions_changed || reset_counters) {
-            op->ofpacts = rule->ofpacts;
-            op->ofpacts_len = rule->ofpacts_len;
-            op->meter_id = rule->meter_id;
+            struct rule_actions *new_actions;
+
+            op->actions = rule->actions;
+            new_actions = rule_actions_create(fm->ofpacts, fm->ofpacts_len);
 
             ovs_rwlock_wrlock(&rule->rwlock);
-            rule->ofpacts = xmemdup(fm->ofpacts, fm->ofpacts_len);
-            rule->ofpacts_len = fm->ofpacts_len;
+            rule->actions = new_actions;
             ovs_rwlock_unlock(&rule->rwlock);
 
-            rule->meter_id = find_meter(rule->ofpacts, rule->ofpacts_len);
             rule->ofproto->ofproto_class->rule_modify_actions(rule,
                                                               reset_counters);
         } else {
@@ -3695,19 +3843,24 @@ modify_flows_loose(struct ofproto *ofproto, struct ofconn *ofconn,
                    struct ofputil_flow_mod *fm,
                    const struct ofp_header *request)
 {
-    struct list rules;
+    struct rule_criteria criteria;
+    struct rule_collection rules;
     int error;
 
-    error = collect_rules_loose(ofproto, fm->table_id, &fm->match,
-                                fm->cookie, fm->cookie_mask,
-                                OFPP_ANY, &rules);
-    if (error) {
-        return error;
-    } else if (list_is_empty(&rules)) {
-        return modify_flows_add(ofproto, ofconn, fm, request);
-    } else {
-        return modify_flows__(ofproto, ofconn, fm, request, &rules);
+    rule_criteria_init(&criteria, fm->table_id, &fm->match, 0,
+                       fm->cookie, fm->cookie_mask, OFPP_ANY);
+    error = collect_rules_loose(ofproto, &criteria, &rules);
+    rule_criteria_destroy(&criteria);
+
+    if (!error) {
+        error = (rules.n > 0
+                 ? modify_flows__(ofproto, ofconn, fm, request, &rules)
+                 : modify_flows_add(ofproto, ofconn, fm, request));
     }
+
+    rule_collection_destroy(&rules);
+
+    return error;
 }
 
 /* Implements OFPFC_MODIFY_STRICT.  Returns 0 on success or an OpenFlow error
@@ -3720,22 +3873,26 @@ modify_flow_strict(struct ofproto *ofproto, struct ofconn *ofconn,
                    struct ofputil_flow_mod *fm,
                    const struct ofp_header *request)
 {
-    struct list rules;
+    struct rule_criteria criteria;
+    struct rule_collection rules;
     int error;
 
-    error = collect_rules_strict(ofproto, fm->table_id, &fm->match,
-                                 fm->priority, fm->cookie, fm->cookie_mask,
-                                 OFPP_ANY, &rules);
+    rule_criteria_init(&criteria, fm->table_id, &fm->match, fm->priority,
+                       fm->cookie, fm->cookie_mask, OFPP_ANY);
+    error = collect_rules_strict(ofproto, &criteria, &rules);
+    rule_criteria_destroy(&criteria);
 
-    if (error) {
-        return error;
-    } else if (list_is_empty(&rules)) {
-        return modify_flows_add(ofproto, ofconn, fm, request);
-    } else {
-        return list_is_singleton(&rules) ? modify_flows__(ofproto, ofconn,
-                                                          fm, request, &rules)
-                                         : 0;
+    if (!error) {
+        if (rules.n == 0) {
+            error =  modify_flows_add(ofproto, ofconn, fm, request);
+        } else if (rules.n == 1) {
+            error = modify_flows__(ofproto, ofconn, fm, request, &rules);
+        }
     }
+
+    rule_collection_destroy(&rules);
+
+    return error;
 }
 \f
 /* OFPFC_DELETE implementation. */
@@ -3758,14 +3915,16 @@ delete_flow__(struct rule *rule, struct ofopgroup *group,
  * Returns 0 on success, otherwise an OpenFlow error code. */
 static enum ofperr
 delete_flows__(struct ofproto *ofproto, struct ofconn *ofconn,
-               const struct ofp_header *request, struct list *rules,
+               const struct ofp_header *request,
+               const struct rule_collection *rules,
                enum ofp_flow_removed_reason reason)
 {
-    struct rule *rule, *next;
     struct ofopgroup *group;
+    size_t i;
 
     group = ofopgroup_create(ofproto, ofconn, request, UINT32_MAX);
-    LIST_FOR_EACH_SAFE (rule, next, ofproto_node, rules) {
+    for (i = 0; i < rules->n; i++) {
+        struct rule *rule = rules->rules[i];
         ovs_rwlock_wrlock(&rule->rwlock);
         delete_flow__(rule, group, reason);
     }
@@ -3780,16 +3939,22 @@ delete_flows_loose(struct ofproto *ofproto, struct ofconn *ofconn,
                    const struct ofputil_flow_mod *fm,
                    const struct ofp_header *request)
 {
-    struct list rules;
+    struct rule_criteria criteria;
+    struct rule_collection rules;
     enum ofperr error;
 
-    error = collect_rules_loose(ofproto, fm->table_id, &fm->match,
-                                fm->cookie, fm->cookie_mask,
-                                fm->out_port, &rules);
-    return (error ? error
-            : !list_is_empty(&rules) ? delete_flows__(ofproto, ofconn, request,
-                                                      &rules, OFPRR_DELETE)
-            : 0);
+    rule_criteria_init(&criteria, fm->table_id, &fm->match, 0,
+                       fm->cookie, fm->cookie_mask,
+                       fm->out_port);
+    error = collect_rules_loose(ofproto, &criteria, &rules);
+    rule_criteria_destroy(&criteria);
+
+    if (!error && rules.n > 0) {
+        error = delete_flows__(ofproto, ofconn, request, &rules, OFPRR_DELETE);
+    }
+    rule_collection_destroy(&rules);
+
+    return error;
 }
 
 /* Implements OFPFC_DELETE_STRICT. */
@@ -3798,17 +3963,21 @@ delete_flow_strict(struct ofproto *ofproto, struct ofconn *ofconn,
                    const struct ofputil_flow_mod *fm,
                    const struct ofp_header *request)
 {
-    struct list rules;
+    struct rule_criteria criteria;
+    struct rule_collection rules;
     enum ofperr error;
 
-    error = collect_rules_strict(ofproto, fm->table_id, &fm->match,
-                                 fm->priority, fm->cookie, fm->cookie_mask,
-                                 fm->out_port, &rules);
-    return (error ? error
-            : list_is_singleton(&rules) ? delete_flows__(ofproto, ofconn,
-                                                         request, &rules,
-                                                         OFPRR_DELETE)
-            : 0);
+    rule_criteria_init(&criteria, fm->table_id, &fm->match, fm->priority,
+                       fm->cookie, fm->cookie_mask, fm->out_port);
+    error = collect_rules_strict(ofproto, &criteria, &rules);
+    rule_criteria_destroy(&criteria);
+
+    if (!error && rules.n > 0) {
+        error = delete_flows__(ofproto, ofconn, request, &rules, OFPRR_DELETE);
+    }
+    rule_collection_destroy(&rules);
+
+    return error;
 }
 
 static void
@@ -3856,7 +4025,7 @@ ofproto_rule_expire(struct rule *rule, uint8_t reason)
     ofproto_rule_send_removed(rule, reason);
 
     ovs_rwlock_wrlock(&cls->rwlock);
-    ofproto_delete_rule(ofproto, cls, rule);
+    ofproto_rule_delete(ofproto, cls, rule);
     ovs_rwlock_unlock(&cls->rwlock);
 }
 
@@ -4143,6 +4312,7 @@ ofproto_compose_flow_refresh_update(const struct rule *rule,
                                     struct list *msgs)
 {
     struct ofoperation *op = rule->pending;
+    const struct rule_actions *actions;
     struct ofputil_flow_update fu;
     struct match match;
 
@@ -4164,12 +4334,11 @@ ofproto_compose_flow_refresh_update(const struct rule *rule,
     minimatch_expand(&rule->cr.match, &match);
     fu.match = &match;
     fu.priority = rule->cr.priority;
+
     if (!(flags & NXFMF_ACTIONS)) {
-        fu.ofpacts = NULL;
-        fu.ofpacts_len = 0;
+        actions = NULL;
     } else if (!op) {
-        fu.ofpacts = rule->ofpacts;
-        fu.ofpacts_len = rule->ofpacts_len;
+        actions = rule->actions;
     } else {
         /* An operation is in progress.  Use the previous version of the flow's
          * actions, so that when the operation commits we report the change. */
@@ -4179,24 +4348,19 @@ ofproto_compose_flow_refresh_update(const struct rule *rule,
 
         case OFOPERATION_MODIFY:
         case OFOPERATION_REPLACE:
-            if (op->ofpacts) {
-                fu.ofpacts = op->ofpacts;
-                fu.ofpacts_len = op->ofpacts_len;
-            } else {
-                fu.ofpacts = rule->ofpacts;
-                fu.ofpacts_len = rule->ofpacts_len;
-            }
+            actions = op->actions ? op->actions : rule->actions;
             break;
 
         case OFOPERATION_DELETE:
-            fu.ofpacts = rule->ofpacts;
-            fu.ofpacts_len = rule->ofpacts_len;
+            actions = rule->actions;
             break;
 
         default:
             NOT_REACHED();
         }
     }
+    fu.ofpacts = actions ? actions->ofpacts : NULL;
+    fu.ofpacts_len = actions ? actions->ofpacts_len : 0;
 
     if (list_is_empty(msgs)) {
         ofputil_start_flow_update(msgs);
@@ -4205,11 +4369,13 @@ ofproto_compose_flow_refresh_update(const struct rule *rule,
 }
 
 void
-ofmonitor_compose_refresh_updates(struct list *rules, struct list *msgs)
+ofmonitor_compose_refresh_updates(struct rule_collection *rules,
+                                  struct list *msgs)
 {
-    struct rule *rule;
+    size_t i;
 
-    LIST_FOR_EACH (rule, ofproto_node, rules) {
+    for (i = 0; i < rules->n; i++) {
+        struct rule *rule = rules->rules[i];
         enum nx_flow_monitor_flags flags = rule->monitor_flags;
         rule->monitor_flags = 0;
 
@@ -4220,7 +4386,7 @@ ofmonitor_compose_refresh_updates(struct list *rules, struct list *msgs)
 static void
 ofproto_collect_ofmonitor_refresh_rule(const struct ofmonitor *m,
                                        struct rule *rule, uint64_t seqno,
-                                       struct list *rules)
+                                       struct rule_collection *rules)
 {
     enum nx_flow_monitor_flags update;
 
@@ -4251,7 +4417,7 @@ ofproto_collect_ofmonitor_refresh_rule(const struct ofmonitor *m,
     }
 
     if (!rule->monitor_flags) {
-        list_push_back(rules, &rule->ofproto_node);
+        rule_collection_add(rules, rule);
     }
     rule->monitor_flags |= update | (m->flags & NXFMF_ACTIONS);
 }
@@ -4259,7 +4425,7 @@ ofproto_collect_ofmonitor_refresh_rule(const struct ofmonitor *m,
 static void
 ofproto_collect_ofmonitor_refresh_rules(const struct ofmonitor *m,
                                         uint64_t seqno,
-                                        struct list *rules)
+                                        struct rule_collection *rules)
 {
     const struct ofproto *ofproto = ofconn_get_ofproto(m->ofconn);
     const struct ofoperation *op;
@@ -4295,7 +4461,7 @@ ofproto_collect_ofmonitor_refresh_rules(const struct ofmonitor *m,
 
 static void
 ofproto_collect_ofmonitor_initial_rules(struct ofmonitor *m,
-                                        struct list *rules)
+                                        struct rule_collection *rules)
 {
     if (m->flags & NXFMF_INITIAL) {
         ofproto_collect_ofmonitor_refresh_rules(m, 0, rules);
@@ -4304,7 +4470,7 @@ ofproto_collect_ofmonitor_initial_rules(struct ofmonitor *m,
 
 void
 ofmonitor_collect_resume_rules(struct ofmonitor *m,
-                               uint64_t seqno, struct list *rules)
+                               uint64_t seqno, struct rule_collection *rules)
 {
     ofproto_collect_ofmonitor_refresh_rules(m, seqno, rules);
 }
@@ -4315,9 +4481,9 @@ handle_flow_monitor_request(struct ofconn *ofconn, const struct ofp_header *oh)
     struct ofproto *ofproto = ofconn_get_ofproto(ofconn);
     struct ofmonitor **monitors;
     size_t n_monitors, allocated_monitors;
+    struct rule_collection rules;
     struct list replies;
     enum ofperr error;
-    struct list rules;
     struct ofpbuf b;
     size_t i;
 
@@ -4356,13 +4522,15 @@ handle_flow_monitor_request(struct ofconn *ofconn, const struct ofp_header *oh)
         monitors[n_monitors++] = m;
     }
 
-    list_init(&rules);
+    rule_collection_init(&rules);
     for (i = 0; i < n_monitors; i++) {
         ofproto_collect_ofmonitor_initial_rules(monitors[i], &rules);
     }
 
     ofpmp_init(&replies, oh);
     ofmonitor_compose_refresh_updates(&rules, &replies);
+    rule_collection_destroy(&rules);
+
     ofconn_send_replies(ofconn, &replies);
 
     free(monitors);
@@ -4521,8 +4689,9 @@ handle_delete_meter(struct ofconn *ofconn, const struct ofp_header *oh,
 {
     struct ofproto *ofproto = ofconn_get_ofproto(ofconn);
     uint32_t meter_id = mm->meter.meter_id;
+    struct rule_collection rules;
+    enum ofperr error = 0;
     uint32_t first, last;
-    struct list rules;
 
     if (meter_id == OFPM13_ALL) {
         first = 1;
@@ -4536,7 +4705,7 @@ handle_delete_meter(struct ofconn *ofconn, const struct ofp_header *oh,
 
     /* First delete the rules that use this meter.  If any of those rules are
      * currently being modified, postpone the whole operation until later. */
-    list_init(&rules);
+    rule_collection_init(&rules);
     for (meter_id = first; meter_id <= last; ++meter_id) {
         struct meter *meter = ofproto->meters[meter_id];
         if (meter && !list_is_empty(&meter->rules)) {
@@ -4544,20 +4713,24 @@ handle_delete_meter(struct ofconn *ofconn, const struct ofp_header *oh,
 
             LIST_FOR_EACH (rule, meter_list_node, &meter->rules) {
                 if (rule->pending) {
-                    return OFPROTO_POSTPONE;
+                    error = OFPROTO_POSTPONE;
+                    goto exit;
                 }
-                list_push_back(&rules, &rule->ofproto_node);
+                rule_collection_add(&rules, rule);
             }
         }
     }
-    if (!list_is_empty(&rules)) {
+    if (rules.n > 0) {
         delete_flows__(ofproto, ofconn, oh, &rules, OFPRR_METER_DELETE);
     }
 
     /* Delete the meters. */
     meter_delete(ofproto, first, last);
 
-    return 0;
+exit:
+    rule_collection_destroy(&rules);
+
+    return error;
 }
 
 static enum ofperr
@@ -4586,9 +4759,12 @@ handle_meter_mod(struct ofconn *ofconn, const struct ofp_header *oh)
 
     if (mm.command != OFPMC13_DELETE) {
         /* Fails also when meters are not implemented by the provider. */
-        if (!meter_id || meter_id > ofproto->meter_features.max_meters) {
+        if (meter_id == 0 || meter_id > OFPM13_MAX) {
             error = OFPERR_OFPMMFC_INVALID_METER;
             goto exit_free_bands;
+        } else if (meter_id > ofproto->meter_features.max_meters) {
+            error = OFPERR_OFPMMFC_OUT_OF_METERS;
+            goto exit_free_bands;
         }
         if (mm.meter.n_bands > ofproto->meter_features.max_bands) {
             error = OFPERR_OFPMMFC_OUT_OF_BANDS;
@@ -4985,7 +5161,7 @@ ofopgroup_complete(struct ofopgroup *group)
         if (!(op->error
               || ofproto_rule_is_hidden(rule)
               || (op->type == OFOPERATION_MODIFY
-                  && op->ofpacts
+                  && op->actions
                   && rule->flow_cookie == op->flow_cookie))) {
             /* Check that we can just cast from ofoperation_type to
              * nx_flow_update_event. */
@@ -5035,13 +5211,13 @@ ofopgroup_complete(struct ofopgroup *group)
             } else {
                 ovs_rwlock_wrlock(&rule->rwlock);
                 oftable_remove_rule(rule);
-                ofproto_rule_destroy(rule);
+                ofproto_rule_unref(rule);
             }
             break;
 
         case OFOPERATION_DELETE:
             ovs_assert(!op->error);
-            ofproto_rule_destroy(rule);
+            ofproto_rule_unref(rule);
             op->rule = NULL;
             break;
 
@@ -5060,16 +5236,16 @@ ofopgroup_complete(struct ofopgroup *group)
                 rule->idle_timeout = op->idle_timeout;
                 rule->hard_timeout = op->hard_timeout;
                 ovs_mutex_unlock(&rule->timeout_mutex);
-                if (op->ofpacts) {
-                    free(rule->ofpacts);
+                if (op->actions) {
+                    struct rule_actions *old_actions;
 
                     ovs_rwlock_wrlock(&rule->rwlock);
-                    rule->ofpacts = op->ofpacts;
-                    rule->ofpacts_len = op->ofpacts_len;
+                    old_actions = rule->actions;
+                    rule->actions = op->actions;
                     ovs_rwlock_unlock(&rule->rwlock);
 
-                    op->ofpacts = NULL;
-                    op->ofpacts_len = 0;
+                    op->actions = NULL;
+                    rule_actions_unref(old_actions);
                 }
                 rule->send_flow_removed = op->send_flow_removed;
             }
@@ -5153,7 +5329,7 @@ ofoperation_destroy(struct ofoperation *op)
         hmap_remove(&group->ofproto->deletions, &op->hmap_node);
     }
     list_remove(&op->group_node);
-    free(op->ofpacts);
+    rule_actions_unref(op->actions);
     free(op);
 }
 
@@ -5607,9 +5783,6 @@ oftable_remove_rule__(struct ofproto *ofproto, struct classifier *cls,
     OVS_REQ_WRLOCK(cls->rwlock) OVS_RELEASES(rule->rwlock)
 {
     classifier_remove(cls, &rule->cr);
-    if (rule->meter_id) {
-        list_remove(&rule->meter_list_node);
-    }
     cookies_remove(ofproto, rule);
     eviction_group_remove_rule(rule);
     ovs_mutex_lock(&ofproto->expirable_mutex);
@@ -5619,6 +5792,7 @@ oftable_remove_rule__(struct ofproto *ofproto, struct classifier *cls,
     ovs_mutex_unlock(&ofproto->expirable_mutex);
     if (!list_is_empty(&rule->meter_list_node)) {
         list_remove(&rule->meter_list_node);
+        list_init(&rule->meter_list_node);
     }
     ovs_rwlock_unlock(&rule->rwlock);
 }
@@ -5653,8 +5827,9 @@ oftable_insert_rule(struct rule *rule)
         ovs_mutex_unlock(&ofproto->expirable_mutex);
     }
     cookies_insert(ofproto, rule);
-    if (rule->meter_id) {
-        struct meter *meter = ofproto->meters[rule->meter_id];
+
+    if (rule->actions->meter_id) {
+        struct meter *meter = ofproto->meters[rule->actions->meter_id];
         list_insert(&meter->rules, &rule->meter_list_node);
     }
     ovs_rwlock_wrlock(&table->cls.rwlock);