ofproto: Eliminate 'ofproto_node' member from struct rule.
[cascardo/ovs.git] / ofproto / ofproto.c
index 3cdc72c..67717e6 100644 (file)
@@ -21,6 +21,7 @@
 #include <inttypes.h>
 #include <stdbool.h>
 #include <stdlib.h>
+#include <unistd.h>
 #include "bitmap.h"
 #include "byte-order.h"
 #include "classifier.h"
@@ -75,7 +76,8 @@ enum ofproto_state {
 enum ofoperation_type {
     OFOPERATION_ADD,
     OFOPERATION_DELETE,
-    OFOPERATION_MODIFY
+    OFOPERATION_MODIFY,
+    OFOPERATION_REPLACE
 };
 
 /* A single OpenFlow request can execute any number of operations.  The
@@ -120,10 +122,8 @@ struct ofoperation {
     struct rule *rule;          /* Rule being operated upon. */
     enum ofoperation_type type; /* Type of operation. */
 
-    /* OFOPERATION_ADD. */
-    struct rule *victim;        /* Rule being replaced, if any.. */
-
-    /* OFOPERATION_MODIFY: The old actions, if the actions are changing. */
+    /* OFOPERATION_MODIFY, OFOPERATION_REPLACE: The old actions, if the actions
+     * are changing. */
     struct ofpact *ofpacts;
     size_t ofpacts_len;
     uint32_t meter_id;
@@ -132,6 +132,9 @@ struct ofoperation {
     enum ofp_flow_removed_reason reason; /* Reason flow was removed. */
 
     ovs_be64 flow_cookie;       /* Rule's old flow cookie. */
+    uint16_t idle_timeout;      /* Rule's old idle timeout. */
+    uint16_t hard_timeout;      /* Rule's old hard timeout. */
+    bool send_flow_removed;     /* Rule's old 'send_flow_removed'. */
     enum ofperr error;          /* 0 if no error. */
 };
 
@@ -152,12 +155,11 @@ static void oftable_enable_eviction(struct oftable *,
                                     const struct mf_subfield *fields,
                                     size_t n_fields);
 
-static void oftable_remove_rule(struct rule *);
+static void oftable_remove_rule(struct rule *rule) OVS_RELEASES(rule->rwlock);
 static void oftable_remove_rule__(struct ofproto *ofproto,
                                   struct classifier *cls, struct rule *rule)
-    OVS_REQ_WRLOCK(cls->rwlock);
-static struct rule *oftable_replace_rule(struct rule *);
-static void oftable_substitute_rule(struct rule *old, struct rule *new);
+    OVS_REQ_WRLOCK(cls->rwlock) OVS_RELEASES(rule->rwlock);
+static void oftable_insert_rule(struct rule *);
 
 /* A set of rules within a single OpenFlow table (oftable) that have the same
  * values for the oftable's eviction_fields.  A rule to be evicted, when one is
@@ -181,9 +183,42 @@ struct eviction_group {
     struct heap rules;          /* Contains "struct rule"s. */
 };
 
-static struct rule *choose_rule_to_evict(struct oftable *);
+static bool choose_rule_to_evict(struct oftable *table, struct rule **rulep)
+    OVS_TRY_WRLOCK(true, (*rulep)->rwlock);
 static void ofproto_evict(struct ofproto *);
 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 *);
@@ -194,6 +229,7 @@ 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 *);
@@ -202,8 +238,13 @@ static bool rule_is_modifiable(const struct rule *);
 static enum ofperr add_flow(struct ofproto *, struct ofconn *,
                             struct ofputil_flow_mod *,
                             const struct ofp_header *);
-static void delete_flow__(struct rule *, struct ofopgroup *,
-                          enum ofp_flow_removed_reason);
+static enum ofperr modify_flows__(struct ofproto *, struct ofconn *,
+                                  struct ofputil_flow_mod *,
+                                  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);
 static bool handle_openflow(struct ofconn *, const struct ofpbuf *);
 static enum ofperr handle_flow_mod__(struct ofproto *, struct ofconn *,
                                      struct ofputil_flow_mod *,
@@ -227,6 +268,7 @@ static size_t n_ofproto_classes;
 static size_t allocated_ofproto_classes;
 
 unsigned flow_eviction_threshold = OFPROTO_FLOW_EVICTION_THRESHOLD_DEFAULT;
+unsigned n_handler_threads;
 enum ofproto_flow_miss_model flow_miss_model = OFPROTO_HANDLE_MISS_AUTO;
 
 /* Map from datapath name to struct ofproto, for use by unixctl commands. */
@@ -428,12 +470,13 @@ ofproto_create(const char *datapath_name, const char *datapath_type,
     hmap_init(&ofproto->ports);
     shash_init(&ofproto->port_by_name);
     simap_init(&ofproto->ofp_requests);
-    ofproto->max_ports = OFPP_MAX;
+    ofproto->max_ports = ofp_to_u16(OFPP_MAX);
+    ofproto->eviction_group_timer = LLONG_MIN;
     ofproto->tables = NULL;
     ofproto->n_tables = 0;
     hindex_init(&ofproto->cookies);
     list_init(&ofproto->expirable);
-    ovs_mutex_init(&ofproto->expirable_mutex, PTHREAD_MUTEX_RECURSIVE);
+    ovs_mutex_init_recursive(&ofproto->expirable_mutex);
     ofproto->connmgr = connmgr_create(ofproto, datapath_name, datapath_name);
     ofproto->state = S_OPENFLOW;
     list_init(&ofproto->pending);
@@ -457,7 +500,7 @@ ofproto_create(const char *datapath_name, const char *datapath_type,
 
     /* The "max_ports" member should have been set by ->construct(ofproto).
      * Port 0 is not a valid OpenFlow port, so mark that as unavailable. */
-    ofproto->ofp_port_ids = bitmap_allocate(ofp_to_u16(ofproto->max_ports));
+    ofproto->ofp_port_ids = bitmap_allocate(ofproto->max_ports);
     bitmap_set1(ofproto->ofp_port_ids, 0);
 
     /* Check that hidden tables, if any, are at the end. */
@@ -516,9 +559,9 @@ ofproto_init_tables(struct ofproto *ofproto, int n_tables)
  * Reserved ports numbered OFPP_MAX and higher are special and not subject to
  * the 'max_ports' restriction. */
 void
-ofproto_init_max_ports(struct ofproto *ofproto, ofp_port_t max_ports)
+ofproto_init_max_ports(struct ofproto *ofproto, uint16_t max_ports)
 {
-    ovs_assert(ofp_to_u16(max_ports) <= ofp_to_u16(OFPP_MAX));
+    ovs_assert(max_ports <= ofp_to_u16(OFPP_MAX));
     ofproto->max_ports = max_ports;
 }
 
@@ -626,6 +669,19 @@ ofproto_set_mac_table_config(struct ofproto *ofproto, unsigned idle_time,
     }
 }
 
+/* Sets number of upcall handler threads.  The default is
+ * (number of online cores - 2). */
+void
+ofproto_set_n_handler_threads(unsigned limit)
+{
+    if (limit) {
+        n_handler_threads = limit;
+    } else {
+        int n_proc = sysconf(_SC_NPROCESSORS_ONLN);
+        n_handler_threads = n_proc > 2 ? n_proc - 2 : 1;
+    }
+}
+
 void
 ofproto_set_dp_desc(struct ofproto *p, const char *dp_desc)
 {
@@ -1052,17 +1108,37 @@ ofproto_get_snoops(const struct ofproto *ofproto, struct sset *snoops)
     connmgr_get_snoops(ofproto->connmgr, snoops);
 }
 
+/* Deletes 'rule' from 'cls' within 'ofproto'.
+ *
+ * The 'cls' argument is redundant (it is &ofproto->tables[rule->table_id].cls)
+ * but it allows Clang to do better checking. */
 static void
-ofproto_flush__(struct ofproto *ofproto)
+ofproto_delete_rule(struct ofproto *ofproto, struct classifier *cls,
+                    struct rule *rule)
+    OVS_REQ_WRLOCK(cls->rwlock)
 {
     struct ofopgroup *group;
+
+    ovs_assert(!rule->pending);
+    ovs_assert(cls == &ofproto->tables[rule->table_id].cls);
+
+    group = ofopgroup_create_unattached(ofproto);
+    ofoperation_create(group, rule, OFOPERATION_DELETE, OFPRR_DELETE);
+    ovs_rwlock_wrlock(&rule->rwlock);
+    oftable_remove_rule__(ofproto, cls, rule);
+    ofproto->ofproto_class->rule_delete(rule);
+    ofopgroup_submit(group);
+}
+
+static void
+ofproto_flush__(struct ofproto *ofproto)
+{
     struct oftable *table;
 
     if (ofproto->ofproto_class->flush) {
         ofproto->ofproto_class->flush(ofproto);
     }
 
-    group = ofopgroup_create_unattached(ofproto);
     OFPROTO_FOR_EACH_TABLE (table, ofproto) {
         struct rule *rule, *next_rule;
         struct cls_cursor cursor;
@@ -1075,15 +1151,11 @@ 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) {
-                ofoperation_create(group, rule, OFOPERATION_DELETE,
-                                   OFPRR_DELETE);
-                oftable_remove_rule__(ofproto, &table->cls, rule);
-                ofproto->ofproto_class->rule_destruct(rule);
+                ofproto_delete_rule(ofproto, &table->cls, rule);
             }
         }
         ovs_rwlock_unlock(&table->cls.rwlock);
     }
-    ofopgroup_submit(group);
 }
 
 static void
@@ -1094,11 +1166,6 @@ 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);
@@ -1136,6 +1203,13 @@ 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);
@@ -1231,6 +1305,38 @@ ofproto_run(struct ofproto *p)
         VLOG_ERR_RL(&rl, "%s: run failed (%s)", p->name, ovs_strerror(error));
     }
 
+    /* Restore the eviction group heap invariant occasionally. */
+    if (p->eviction_group_timer < time_msec()) {
+        size_t i;
+
+        p->eviction_group_timer = time_msec() + 1000;
+
+        for (i = 0; i < p->n_tables; i++) {
+            struct oftable *table = &p->tables[i];
+            struct eviction_group *evg;
+            struct cls_cursor cursor;
+            struct rule *rule;
+
+            if (!table->eviction_fields) {
+                continue;
+            }
+
+            HEAP_FOR_EACH (evg, size_node, &table->eviction_groups_by_size) {
+                heap_rebuild(&evg->rules);
+            }
+
+            ovs_rwlock_rdlock(&table->cls.rwlock);
+            cls_cursor_init(&cursor, &table->cls, NULL);
+            CLS_CURSOR_FOR_EACH (rule, cr, &cursor) {
+                if (!rule->eviction_group
+                    && (rule->idle_timeout || rule->hard_timeout)) {
+                    eviction_group_add_rule(rule);
+                }
+            }
+            ovs_rwlock_unlock(&table->cls.rwlock);
+        }
+    }
+
     if (p->ofproto_class->port_poll) {
         char *devname;
 
@@ -1661,12 +1767,13 @@ bool
 ofproto_delete_flow(struct ofproto *ofproto,
                     const struct match *target, unsigned int priority)
 {
+    struct classifier *cls = &ofproto->tables[0].cls;
     struct rule *rule;
 
-    ovs_rwlock_rdlock(&ofproto->tables[0].cls.rwlock);
-    rule = rule_from_cls_rule(classifier_find_match_exactly(
-                                  &ofproto->tables[0].cls, target, priority));
-    ovs_rwlock_unlock(&ofproto->tables[0].cls.rwlock);
+    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;
@@ -1676,11 +1783,10 @@ ofproto_delete_flow(struct ofproto *ofproto,
         return false;
     } else {
         /* Initiate deletion -> success. */
-        struct ofopgroup *group = ofopgroup_create_unattached(ofproto);
-        ofoperation_create(group, rule, OFOPERATION_DELETE, OFPRR_DELETE);
-        oftable_remove_rule(rule);
-        ofproto->ofproto_class->rule_destruct(rule);
-        ofopgroup_submit(group);
+        ovs_rwlock_wrlock(&cls->rwlock);
+        ofproto_delete_rule(ofproto, cls, rule);
+        ovs_rwlock_unlock(&cls->rwlock);
+
         return true;
     }
 
@@ -1724,32 +1830,28 @@ reinit_ports(struct ofproto *p)
 static ofp_port_t
 alloc_ofp_port(struct ofproto *ofproto, const char *netdev_name)
 {
-    uint16_t max_ports = ofp_to_u16(ofproto->max_ports);
     uint16_t port_idx;
 
     port_idx = simap_get(&ofproto->ofp_requests, netdev_name);
-    if (!port_idx) {
-        port_idx = UINT16_MAX;
-    }
+    port_idx = port_idx ? port_idx : UINT16_MAX;
 
-    if (port_idx >= max_ports
+    if (port_idx >= ofproto->max_ports
         || bitmap_is_set(ofproto->ofp_port_ids, port_idx)) {
-        uint16_t end_port_no = ofp_to_u16(ofproto->alloc_port_no);
-        uint16_t alloc_port_no = end_port_no;
+        uint16_t end_port_no = ofproto->alloc_port_no;
 
         /* Search for a free OpenFlow port number.  We try not to
          * immediately reuse them to prevent problems due to old
          * flows. */
         for (;;) {
-            if (++alloc_port_no >= max_ports) {
-                alloc_port_no = 0;
+            if (++ofproto->alloc_port_no >= ofproto->max_ports) {
+                ofproto->alloc_port_no = 0;
             }
-            if (!bitmap_is_set(ofproto->ofp_port_ids, alloc_port_no)) {
-                port_idx = alloc_port_no;
-                ofproto->alloc_port_no = u16_to_ofp(alloc_port_no);
+            if (!bitmap_is_set(ofproto->ofp_port_ids,
+                               ofproto->alloc_port_no)) {
+                port_idx = ofproto->alloc_port_no;
                 break;
             }
-            if (alloc_port_no == end_port_no) {
+            if (ofproto->alloc_port_no == end_port_no) {
                 return OFPP_NONE;
             }
         }
@@ -1761,7 +1863,7 @@ alloc_ofp_port(struct ofproto *ofproto, const char *netdev_name)
 static void
 dealloc_ofp_port(const struct ofproto *ofproto, ofp_port_t ofp_port)
 {
-    if (ofp_to_u16(ofp_port) < ofp_to_u16(ofproto->max_ports)) {
+    if (ofp_to_u16(ofp_port) < ofproto->max_ports) {
         bitmap_set0(ofproto->ofp_port_ids, ofp_to_u16(ofp_port));
     }
 }
@@ -1804,8 +1906,8 @@ ofport_open(struct ofproto *ofproto,
     pp->state = netdev_get_carrier(netdev) ? 0 : OFPUTIL_PS_LINK_DOWN;
     netdev_get_features(netdev, &pp->curr, &pp->advertised,
                         &pp->supported, &pp->peer);
-    pp->curr_speed = netdev_features_to_bps(pp->curr, 0);
-    pp->max_speed = netdev_features_to_bps(pp->supported, 0);
+    pp->curr_speed = netdev_features_to_bps(pp->curr, 0) / 1000;
+    pp->max_speed = netdev_features_to_bps(pp->supported, 0) / 1000;
 
     return netdev;
 }
@@ -2085,6 +2187,10 @@ init_ports(struct ofproto *p)
             netdev = ofport_open(p, &ofproto_port, &pp);
             if (netdev) {
                 ofport_install(p, netdev, &pp);
+                if (ofp_to_u16(ofproto_port.ofp_port) < p->max_ports) {
+                    p->alloc_port_no = MAX(p->alloc_port_no,
+                                           ofp_to_u16(ofproto_port.ofp_port));
+                }
             }
         }
     }
@@ -2175,31 +2281,37 @@ update_mtu(struct ofproto *p, struct ofport *port)
 }
 \f
 static void
-ofproto_rule_destroy__(struct rule *rule)
+ofproto_rule_destroy(struct rule *rule)
 {
     if (rule) {
-        cls_rule_destroy(&rule->cr);
-        free(rule->ofpacts);
-        ovs_mutex_destroy(&rule->timeout_mutex);
-        rule->ofproto->ofproto_class->rule_dealloc(rule);
+        rule->ofproto->ofproto_class->rule_destruct(rule);
+        ofproto_rule_destroy__(rule);
     }
 }
 
+static void
+ofproto_rule_destroy__(struct rule *rule)
+{
+    cls_rule_destroy(&rule->cr);
+    free(rule->ofpacts);
+    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.  The caller must have
- * already uninitialized any derived members of 'rule' (step 5 described in the
- * large comment in ofproto/ofproto-provider.h titled "Life Cycle").
- * This function implements steps 6 and 7.
+ * 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. */
 void
-ofproto_rule_destroy(struct ofproto *ofproto, struct classifier *cls,
-                     struct rule *rule) OVS_REQ_WRLOCK(cls->rwlock)
+ofproto_rule_delete(struct ofproto *ofproto, struct classifier *cls,
+                    struct rule *rule)
+    OVS_REQ_WRLOCK(cls->rwlock)
 {
-    ovs_assert(!rule->pending);
-    oftable_remove_rule__(ofproto, cls, rule);
-    ofproto_rule_destroy__(rule);
+    ofproto_delete_rule(ofproto, cls, rule);
 }
 
 /* Returns true if 'rule' has an OpenFlow OFPAT_OUTPUT or OFPAT_ENQUEUE action
@@ -2222,12 +2334,11 @@ ofoperation_has_out_port(const struct ofoperation *op, ofp_port_t out_port)
 
     switch (op->type) {
     case OFOPERATION_ADD:
-        return op->victim && ofproto_rule_has_out_port(op->victim, out_port);
-
     case OFOPERATION_DELETE:
         return false;
 
     case OFOPERATION_MODIFY:
+    case OFOPERATION_REPLACE:
         return ofpacts_output_to_port(op->ofpacts, op->ofpacts_len, out_port);
     }
 
@@ -2235,8 +2346,7 @@ ofoperation_has_out_port(const struct ofoperation *op, ofp_port_t out_port)
 }
 
 /* Executes the actions indicated by 'rule' on 'packet' and credits 'rule''s
- * statistics appropriately.  'packet' must have at least sizeof(struct
- * ofp10_packet_in) bytes of headroom.
+ * statistics appropriately.
  *
  * 'packet' doesn't necessarily have to match 'rule'.  'rule' will be credited
  * with statistics for 'packet' either way.
@@ -2248,8 +2358,6 @@ rule_execute(struct rule *rule, ofp_port_t in_port, struct ofpbuf *packet)
     struct flow flow;
     union flow_in_port in_port_;
 
-    ovs_assert(ofpbuf_headroom(packet) >= sizeof(struct ofp10_packet_in));
-
     in_port_.ofp_port = in_port;
     flow_extract(packet, 0, 0, NULL, &in_port_, &flow);
     return rule->ofproto->ofproto_class->rule_execute(rule, &flow, packet);
@@ -2439,8 +2547,8 @@ ofproto_check_ofpacts(struct ofproto *ofproto,
     enum ofperr error;
     uint32_t mid;
 
-    error = ofpacts_check(ofpacts, ofpacts_len, flow, ofproto->max_ports,
-                          table_id);
+    error = ofpacts_check(ofpacts, ofpacts_len, flow,
+                          u16_to_ofp(ofproto->max_ports), table_id);
     if (error) {
         return error;
     }
@@ -2477,7 +2585,7 @@ handle_packet_out(struct ofconn *ofconn, const struct ofp_header *oh)
     if (error) {
         goto exit_free_ofpacts;
     }
-    if (ofp_to_u16(po.in_port) >= ofp_to_u16(p->max_ports)
+    if (ofp_to_u16(po.in_port) >= p->max_ports
         && ofp_to_u16(po.in_port) < ofp_to_u16(OFPP_MAX)) {
         error = OFPERR_OFPBRC_BAD_PORT;
         goto exit_free_ofpacts;
@@ -2491,8 +2599,8 @@ handle_packet_out(struct ofconn *ofconn, const struct ofp_header *oh)
             goto exit_free_ofpacts;
         }
     } else {
-        payload = xmalloc(sizeof *payload);
-        ofpbuf_use_const(payload, po.packet, po.packet_len);
+        /* Ensure that the L3 header is 32-bit aligned. */
+        payload = ofpbuf_clone_data_with_headroom(po.packet, po.packet_len, 2);
     }
 
     /* Verify actions against packet, then send packet if successful. */
@@ -2758,7 +2866,9 @@ ofproto_rule_change_cookie(struct ofproto *ofproto, struct rule *rule,
     if (new_cookie != rule->flow_cookie) {
         cookies_remove(ofproto, rule);
 
+        ovs_rwlock_wrlock(&rule->rwlock);
         rule->flow_cookie = new_cookie;
+        ovs_rwlock_unlock(&rule->rwlock);
 
         cookies_insert(ofproto, rule);
     }
@@ -2841,163 +2951,203 @@ 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
@@ -3016,25 +3166,28 @@ 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;
 
@@ -3049,20 +3202,22 @@ handle_flow_stats_request(struct ofconn *ofconn,
                                                &fs.byte_count);
         fs.ofpacts = rule->ofpacts;
         fs.ofpacts_len = rule->ofpacts_len;
-        fs.flags = 0;
 
         ovs_mutex_lock(&rule->timeout_mutex);
         fs.idle_timeout = rule->idle_timeout;
         fs.hard_timeout = rule->hard_timeout;
         ovs_mutex_unlock(&rule->timeout_mutex);
 
+        fs.flags = 0;
         if (rule->send_flow_removed) {
-            fs.flags |= OFPFF_SEND_FLOW_REM;
-            /* FIXME: Implement OF 1.3 flags OFPFF13_NO_PKT_COUNTS
-               and OFPFF13_NO_BYT_COUNTS */
+            fs.flags |= OFPUTIL_FF_SEND_FLOW_REM;
+            /* FIXME: Implement OFPUTIL_FF_NO_PKT_COUNTS and
+               OFPUTIL_FF_NO_BYT_COUNTS. */
         }
         ofputil_append_flow_stats_reply(&fs, &replies);
     }
+    rule_collection_destroy(&rules);
+
     ofconn_send_replies(ofconn, &replies);
 
     return 0;
@@ -3143,26 +3298,30 @@ 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;
 
@@ -3190,6 +3349,8 @@ 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);
 
@@ -3314,6 +3475,34 @@ is_flow_deletion_pending(const struct ofproto *ofproto,
     return false;
 }
 
+static enum ofperr
+evict_rule_from_table(struct ofproto *ofproto, struct oftable *table)
+{
+    struct rule *rule;
+    size_t n_rules;
+
+    ovs_rwlock_rdlock(&table->cls.rwlock);
+    n_rules = classifier_count(&table->cls);
+    ovs_rwlock_unlock(&table->cls.rwlock);
+
+    if (n_rules < table->max_flows) {
+        return 0;
+    } else if (!choose_rule_to_evict(table, &rule)) {
+        return OFPERR_OFPFMFC_TABLE_FULL;
+    } else if (rule->pending) {
+        ovs_rwlock_unlock(&rule->rwlock);
+        return OFPROTO_POSTPONE;
+    } else {
+        struct ofopgroup *group;
+
+        group = ofopgroup_create_unattached(ofproto);
+        delete_flow__(rule, group, OFPRR_EVICTION);
+        ofopgroup_submit(group);
+
+        return 0;
+    }
+}
+
 /* Implements OFPFC_ADD and the cases for OFPFC_MODIFY and OFPFC_MODIFY_STRICT
  * in which no matching flow already exists in the flow table.
  *
@@ -3333,10 +3522,9 @@ add_flow(struct ofproto *ofproto, struct ofconn *ofconn,
 {
     struct oftable *table;
     struct ofopgroup *group;
-    struct rule *victim;
+    struct cls_rule cr;
     struct rule *rule;
     uint8_t table_id;
-    bool overlaps;
     int error;
 
     error = check_table_id(ofproto, fm->table_id);
@@ -3369,120 +3557,116 @@ add_flow(struct ofproto *ofproto, struct ofconn *ofconn,
         return OFPERR_OFPBRC_EPERM;
     }
 
+    cls_rule_init(&cr, &fm->match, fm->priority);
+
+    /* Transform "add" into "modify" if there's an existing identical flow. */
+    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) {
+        cls_rule_destroy(&cr);
+        if (!rule_is_modifiable(rule)) {
+            return OFPERR_OFPBRC_EPERM;
+        } else if (rule->pending) {
+            return OFPROTO_POSTPONE;
+        } else {
+            struct rule_collection rules;
+
+            rule_collection_init(&rules);
+            rule_collection_add(&rules, rule);
+            fm->modify_cookie = true;
+            error = modify_flows__(ofproto, ofconn, fm, request, &rules);
+            rule_collection_destroy(&rules);
+
+            return error;
+        }
+    }
+
     /* Verify actions. */
     error = ofproto_check_ofpacts(ofproto, fm->ofpacts, fm->ofpacts_len,
                                   &fm->match.flow, table_id);
     if (error) {
+        cls_rule_destroy(&cr);
         return error;
     }
 
-    /* Allocate new rule and initialize classifier rule. */
-    rule = ofproto->ofproto_class->rule_alloc();
-    if (!rule) {
-        VLOG_WARN_RL(&rl, "%s: failed to create rule (%s)",
-                     ofproto->name, ovs_strerror(error));
-        return ENOMEM;
-    }
-    cls_rule_init(&rule->cr, &fm->match, fm->priority);
-
     /* Serialize against pending deletion. */
-    if (is_flow_deletion_pending(ofproto, &rule->cr, table_id)) {
-        cls_rule_destroy(&rule->cr);
-        ofproto->ofproto_class->rule_dealloc(rule);
+    if (is_flow_deletion_pending(ofproto, &cr, table_id)) {
+        cls_rule_destroy(&cr);
         return OFPROTO_POSTPONE;
     }
 
     /* Check for overlap, if requested. */
-    ovs_rwlock_rdlock(&table->cls.rwlock);
-    overlaps = classifier_rule_overlaps(&table->cls, &rule->cr);
-    ovs_rwlock_unlock(&table->cls.rwlock);
-    if (fm->flags & OFPFF_CHECK_OVERLAP && overlaps) {
-        cls_rule_destroy(&rule->cr);
-        ofproto->ofproto_class->rule_dealloc(rule);
-        return OFPERR_OFPFMFC_OVERLAP;
+    if (fm->flags & OFPUTIL_FF_CHECK_OVERLAP) {
+        bool overlaps;
+
+        ovs_rwlock_rdlock(&table->cls.rwlock);
+        overlaps = classifier_rule_overlaps(&table->cls, &cr);
+        ovs_rwlock_unlock(&table->cls.rwlock);
+
+        if (overlaps) {
+            cls_rule_destroy(&cr);
+            return OFPERR_OFPFMFC_OVERLAP;
+        }
+    }
+
+    /* If necessary, evict an existing rule to clear out space. */
+    error = evict_rule_from_table(ofproto, table);
+    if (error) {
+        cls_rule_destroy(&cr);
+        return error;
     }
 
-    /* FIXME: Implement OFPFF12_RESET_COUNTS */
+    /* Allocate new rule. */
+    rule = ofproto->ofproto_class->rule_alloc();
+    if (!rule) {
+        cls_rule_destroy(&cr);
+        VLOG_WARN_RL(&rl, "%s: failed to create rule (%s)",
+                     ofproto->name, ovs_strerror(error));
+        return ENOMEM;
+    }
 
+    /* Initialize base state. */
     rule->ofproto = ofproto;
+    cls_rule_move(&rule->cr, &cr);
     rule->pending = NULL;
     rule->flow_cookie = fm->new_cookie;
     rule->created = rule->modified = rule->used = time_msec();
 
-    ovs_mutex_init(&rule->timeout_mutex, OVS_MUTEX_ADAPTIVE);
+    ovs_mutex_init(&rule->timeout_mutex);
     ovs_mutex_lock(&rule->timeout_mutex);
     rule->idle_timeout = fm->idle_timeout;
     rule->hard_timeout = fm->hard_timeout;
     ovs_mutex_unlock(&rule->timeout_mutex);
 
     rule->table_id = table - ofproto->tables;
-    rule->send_flow_removed = (fm->flags & OFPFF_SEND_FLOW_REM) != 0;
-    /* FIXME: Implement OF 1.3 flags OFPFF13_NO_PKT_COUNTS
-       and OFPFF13_NO_BYT_COUNTS */
+    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);
     list_init(&rule->meter_list_node);
-    rule->evictable = true;
     rule->eviction_group = NULL;
     list_init(&rule->expirable);
     rule->monitor_flags = 0;
     rule->add_seqno = 0;
     rule->modify_seqno = 0;
+    ovs_rwlock_init(&rule->rwlock);
 
-    /* Insert new rule. */
-    victim = oftable_replace_rule(rule);
-    if (victim && !rule_is_modifiable(victim)) {
-        error = OFPERR_OFPBRC_EPERM;
-    } else if (victim && victim->pending) {
-        error = OFPROTO_POSTPONE;
-    } else {
-        struct ofoperation *op;
-        struct rule *evict;
-        size_t n_rules;
-
-        ovs_rwlock_rdlock(&table->cls.rwlock);
-        n_rules = classifier_count(&table->cls);
-        ovs_rwlock_unlock(&table->cls.rwlock);
-        if (n_rules > table->max_flows) {
-            bool was_evictable;
-
-            was_evictable = rule->evictable;
-            rule->evictable = false;
-            evict = choose_rule_to_evict(table);
-            rule->evictable = was_evictable;
-
-            if (!evict) {
-                error = OFPERR_OFPFMFC_TABLE_FULL;
-                goto exit;
-            } else if (evict->pending) {
-                error = OFPROTO_POSTPONE;
-                goto exit;
-            }
-        } else {
-            evict = NULL;
-        }
-
-        group = ofopgroup_create(ofproto, ofconn, request, fm->buffer_id);
-        op = ofoperation_create(group, rule, OFOPERATION_ADD, 0);
-        op->victim = victim;
-
-        error = ofproto->ofproto_class->rule_construct(rule);
-        if (error) {
-            op->group->n_running--;
-            ofoperation_destroy(rule->pending);
-        } else if (evict) {
-            delete_flow__(evict, group, OFPRR_EVICTION);
-        }
-        ofopgroup_submit(group);
-    }
-
-exit:
-    /* Back out if an error occurred. */
+    /* Construct rule, initializing derived state. */
+    error = ofproto->ofproto_class->rule_construct(rule);
     if (error) {
-        oftable_substitute_rule(rule, victim);
         ofproto_rule_destroy__(rule);
+        return error;
     }
+
+    /* Insert rule. */
+    oftable_insert_rule(rule);
+
+    group = ofopgroup_create(ofproto, ofconn, request, fm->buffer_id);
+    ofoperation_create(group, rule, OFOPERATION_ADD, 0);
+    ofproto->ofproto_class->rule_insert(rule);
+    ofopgroup_submit(group);
+
     return error;
 }
 \f
@@ -3498,19 +3682,23 @@ exit:
 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;
 
-        /* FIXME: Implement OFPFF12_RESET_COUNTS */
+        /* FIXME: Implement OFPFUTIL_FF_RESET_COUNTS */
 
         if (rule_is_modifiable(rule)) {
             /* At least one rule is modifiable, don't report EPERM error. */
@@ -3521,7 +3709,7 @@ modify_flows__(struct ofproto *ofproto, struct ofconn *ofconn,
 
         /* Verify actions. */
         error = ofpacts_check(fm->ofpacts, fm->ofpacts_len, &fm->match.flow,
-                              ofproto->max_ports, rule->table_id);
+                              u16_to_ofp(ofproto->max_ports), rule->table_id);
         if (error) {
             return error;
         }
@@ -3529,19 +3717,43 @@ modify_flows__(struct ofproto *ofproto, struct ofconn *ofconn,
         actions_changed = !ofpacts_equal(fm->ofpacts, fm->ofpacts_len,
                                          rule->ofpacts, rule->ofpacts_len);
 
-        op = ofoperation_create(group, rule, OFOPERATION_MODIFY, 0);
+        op = ofoperation_create(group, rule, type, 0);
 
         if (fm->modify_cookie && fm->new_cookie != htonll(UINT64_MAX)) {
             ofproto_rule_change_cookie(ofproto, rule, fm->new_cookie);
         }
-        if (actions_changed) {
+        if (type == OFOPERATION_REPLACE) {
+            ovs_mutex_lock(&rule->timeout_mutex);
+            rule->idle_timeout = fm->idle_timeout;
+            rule->hard_timeout = fm->hard_timeout;
+            ovs_mutex_unlock(&rule->timeout_mutex);
+
+            rule->send_flow_removed = (fm->flags
+                                       & OFPUTIL_FF_SEND_FLOW_REM) != 0;
+
+            if (fm->idle_timeout || fm->hard_timeout) {
+                if (!rule->eviction_group) {
+                    eviction_group_add_rule(rule);
+                }
+            } else {
+                eviction_group_remove_rule(rule);
+            }
+        }
+
+        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;
+
+            ovs_rwlock_wrlock(&rule->rwlock);
             rule->ofpacts = xmemdup(fm->ofpacts, fm->ofpacts_len);
             rule->ofpacts_len = fm->ofpacts_len;
+            ovs_rwlock_unlock(&rule->rwlock);
+
             rule->meter_id = find_meter(rule->ofpacts, rule->ofpacts_len);
-            rule->ofproto->ofproto_class->rule_modify_actions(rule);
+            rule->ofproto->ofproto_class->rule_modify_actions(rule,
+                                                              reset_counters);
         } else {
             ofoperation_complete(op, 0);
         }
@@ -3571,19 +3783,24 @@ 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
@@ -3596,22 +3813,26 @@ 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. */
@@ -3626,7 +3847,7 @@ delete_flow__(struct rule *rule, struct ofopgroup *group,
 
     ofoperation_create(group, rule, OFOPERATION_DELETE, reason);
     oftable_remove_rule(rule);
-    ofproto->ofproto_class->rule_destruct(rule);
+    ofproto->ofproto_class->rule_delete(rule);
 }
 
 /* Deletes the rules listed in 'rules'.
@@ -3634,14 +3855,17 @@ 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);
     }
     ofopgroup_submit(group);
@@ -3655,16 +3879,22 @@ 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. */
@@ -3673,17 +3903,21 @@ 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
@@ -3712,20 +3946,6 @@ ofproto_rule_send_removed(struct rule *rule, uint8_t reason)
     connmgr_send_flow_removed(rule->ofproto->connmgr, &fr);
 }
 
-void
-ofproto_rule_update_used(struct rule *rule, long long int used)
-{
-    if (used > rule->used) {
-        struct eviction_group *evg = rule->eviction_group;
-
-        rule->used = used;
-        if (evg) {
-            heap_change(&evg->rules, &rule->evg_node,
-                        rule_eviction_priority(rule));
-        }
-    }
-}
-
 /* Sends an OpenFlow "flow removed" message with the given 'reason' (either
  * OFPRR_HARD_TIMEOUT or OFPRR_IDLE_TIMEOUT), and then removes 'rule' from its
  * ofproto.
@@ -3739,17 +3959,50 @@ void
 ofproto_rule_expire(struct rule *rule, uint8_t reason)
 {
     struct ofproto *ofproto = rule->ofproto;
-    struct ofopgroup *group;
+    struct classifier *cls = &ofproto->tables[rule->table_id].cls;
 
     ovs_assert(reason == OFPRR_HARD_TIMEOUT || reason == OFPRR_IDLE_TIMEOUT);
-
     ofproto_rule_send_removed(rule, reason);
 
-    group = ofopgroup_create_unattached(ofproto);
-    ofoperation_create(group, rule, OFOPERATION_DELETE, reason);
-    oftable_remove_rule(rule);
-    ofproto->ofproto_class->rule_destruct(rule);
-    ofopgroup_submit(group);
+    ovs_rwlock_wrlock(&cls->rwlock);
+    ofproto_delete_rule(ofproto, cls, rule);
+    ovs_rwlock_unlock(&cls->rwlock);
+}
+
+/* Reduces '*timeout' to no more than 'max'.  A value of zero in either case
+ * means "infinite". */
+static void
+reduce_timeout(uint16_t max, uint16_t *timeout)
+{
+    if (max && (!*timeout || *timeout > max)) {
+        *timeout = max;
+    }
+}
+
+/* If 'idle_timeout' is nonzero, and 'rule' has no idle timeout or an idle
+ * timeout greater than 'idle_timeout', lowers 'rule''s idle timeout to
+ * 'idle_timeout' seconds.  Similarly for 'hard_timeout'.
+ *
+ * Suitable for implementing OFPACT_FIN_TIMEOUT. */
+void
+ofproto_rule_reduce_timeouts(struct rule *rule,
+                             uint16_t idle_timeout, uint16_t hard_timeout)
+    OVS_EXCLUDED(rule->ofproto->expirable_mutex, rule->timeout_mutex)
+{
+    if (!idle_timeout && !hard_timeout) {
+        return;
+    }
+
+    ovs_mutex_lock(&rule->ofproto->expirable_mutex);
+    if (list_is_empty(&rule->expirable)) {
+        list_insert(&rule->ofproto->expirable, &rule->expirable);
+    }
+    ovs_mutex_unlock(&rule->ofproto->expirable_mutex);
+
+    ovs_mutex_lock(&rule->timeout_mutex);
+    reduce_timeout(idle_timeout, &rule->idle_timeout);
+    reduce_timeout(hard_timeout, &rule->hard_timeout);
+    ovs_mutex_unlock(&rule->timeout_mutex);
 }
 \f
 static enum ofperr
@@ -4002,7 +4255,7 @@ ofproto_compose_flow_refresh_update(const struct rule *rule,
     struct ofputil_flow_update fu;
     struct match match;
 
-    if (op && op->type == OFOPERATION_ADD && !op->victim) {
+    if (op && op->type == OFOPERATION_ADD) {
         /* We'll report the final flow when the operation completes.  Reporting
          * it now would cause a duplicate report later. */
         return;
@@ -4031,12 +4284,10 @@ ofproto_compose_flow_refresh_update(const struct rule *rule,
          * actions, so that when the operation commits we report the change. */
         switch (op->type) {
         case OFOPERATION_ADD:
-            /* We already verified that there was a victim. */
-            fu.ofpacts = op->victim->ofpacts;
-            fu.ofpacts_len = op->victim->ofpacts_len;
-            break;
+            NOT_REACHED();
 
         case OFOPERATION_MODIFY:
+        case OFOPERATION_REPLACE:
             if (op->ofpacts) {
                 fu.ofpacts = op->ofpacts;
                 fu.ofpacts_len = op->ofpacts_len;
@@ -4063,11 +4314,13 @@ 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;
 
@@ -4078,7 +4331,7 @@ 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;
 
@@ -4109,7 +4362,7 @@ 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);
 }
@@ -4117,7 +4370,7 @@ 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;
@@ -4153,7 +4406,7 @@ 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);
@@ -4162,7 +4415,7 @@ 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);
 }
@@ -4173,9 +4426,9 @@ 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;
 
@@ -4214,13 +4467,15 @@ 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);
@@ -4379,8 +4634,9 @@ 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;
@@ -4394,7 +4650,7 @@ 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)) {
@@ -4402,20 +4658,24 @@ 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
@@ -4444,9 +4704,12 @@ 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;
@@ -4847,15 +5110,27 @@ ofopgroup_complete(struct ofopgroup *group)
                   && rule->flow_cookie == op->flow_cookie))) {
             /* Check that we can just cast from ofoperation_type to
              * nx_flow_update_event. */
-            BUILD_ASSERT_DECL((enum nx_flow_update_event) OFOPERATION_ADD
-                              == NXFME_ADDED);
-            BUILD_ASSERT_DECL((enum nx_flow_update_event) OFOPERATION_DELETE
-                              == NXFME_DELETED);
-            BUILD_ASSERT_DECL((enum nx_flow_update_event) OFOPERATION_MODIFY
-                              == NXFME_MODIFIED);
-
-            ofmonitor_report(ofproto->connmgr, rule,
-                             (enum nx_flow_update_event) op->type,
+            enum nx_flow_update_event event_type;
+
+            switch (op->type) {
+            case OFOPERATION_ADD:
+            case OFOPERATION_REPLACE:
+                event_type = NXFME_ADDED;
+                break;
+
+            case OFOPERATION_DELETE:
+                event_type = NXFME_DELETED;
+                break;
+
+            case OFOPERATION_MODIFY:
+                event_type = NXFME_MODIFIED;
+                break;
+
+            default:
+                NOT_REACHED();
+            }
+
+            ofmonitor_report(ofproto->connmgr, rule, event_type,
                              op->reason, abbrev_ofconn, abbrev_xid);
         }
 
@@ -4866,7 +5141,6 @@ ofopgroup_complete(struct ofopgroup *group)
             if (!op->error) {
                 uint16_t vid_mask;
 
-                ofproto_rule_destroy__(op->victim);
                 vid_mask = minimask_get_vid_mask(&rule->cr.match.mask);
                 if (vid_mask == VLAN_VID_MASK) {
                     if (ofproto->vlan_bitmap) {
@@ -4880,29 +5154,45 @@ ofopgroup_complete(struct ofopgroup *group)
                     }
                 }
             } else {
-                oftable_substitute_rule(rule, op->victim);
-                ofproto_rule_destroy__(rule);
+                ovs_rwlock_wrlock(&rule->rwlock);
+                oftable_remove_rule(rule);
+                ofproto_rule_destroy(rule);
             }
             break;
 
         case OFOPERATION_DELETE:
             ovs_assert(!op->error);
-            ofproto_rule_destroy__(rule);
+            ofproto_rule_destroy(rule);
             op->rule = NULL;
             break;
 
         case OFOPERATION_MODIFY:
+        case OFOPERATION_REPLACE:
             if (!op->error) {
-                rule->modified = time_msec();
+                long long int now = time_msec();
+
+                rule->modified = now;
+                if (op->type == OFOPERATION_REPLACE) {
+                    rule->created = rule->used = now;
+                }
             } else {
                 ofproto_rule_change_cookie(ofproto, rule, op->flow_cookie);
+                ovs_mutex_lock(&rule->timeout_mutex);
+                rule->idle_timeout = op->idle_timeout;
+                rule->hard_timeout = op->hard_timeout;
+                ovs_mutex_unlock(&rule->timeout_mutex);
                 if (op->ofpacts) {
                     free(rule->ofpacts);
+
+                    ovs_rwlock_wrlock(&rule->rwlock);
                     rule->ofpacts = op->ofpacts;
                     rule->ofpacts_len = op->ofpacts_len;
+                    ovs_rwlock_unlock(&rule->rwlock);
+
                     op->ofpacts = NULL;
                     op->ofpacts_len = 0;
                 }
+                rule->send_flow_removed = op->send_flow_removed;
             }
             break;
 
@@ -4956,6 +5246,11 @@ ofoperation_create(struct ofopgroup *group, struct rule *rule,
     op->type = type;
     op->reason = reason;
     op->flow_cookie = rule->flow_cookie;
+    ovs_mutex_lock(&rule->timeout_mutex);
+    op->idle_timeout = rule->idle_timeout;
+    op->hard_timeout = rule->hard_timeout;
+    ovs_mutex_unlock(&rule->timeout_mutex);
+    op->send_flow_removed = rule->send_flow_removed;
 
     group->n_running++;
 
@@ -4987,14 +5282,7 @@ ofoperation_destroy(struct ofoperation *op)
  * indicate success or an OpenFlow error code on failure.
  *
  * If 'error' is 0, indicating success, the operation will be committed
- * permanently to the flow table.  There is one interesting subcase:
- *
- *   - If 'op' is an "add flow" operation that is replacing an existing rule in
- *     the flow table (the "victim" rule) by a new one, then the caller must
- *     have uninitialized any derived state in the victim rule, as in step 5 in
- *     the "Life Cycle" in ofproto/ofproto-provider.h.  ofoperation_complete()
- *     performs steps 6 and 7 for the victim rule, most notably by calling its
- *     ->rule_dealloc() function.
+ * permanently to the flow table.
  *
  * If 'error' is nonzero, then generally the operation will be rolled back:
  *
@@ -5026,13 +5314,6 @@ ofoperation_complete(struct ofoperation *op, enum ofperr error)
         ofopgroup_complete(group);
     }
 }
-
-struct rule *
-ofoperation_get_victim(struct ofoperation *op)
-{
-    ovs_assert(op->type == OFOPERATION_ADD);
-    return op->victim;
-}
 \f
 static uint64_t
 pick_datapath_id(const struct ofproto *ofproto)
@@ -5065,17 +5346,18 @@ pick_fallback_dpid(void)
 \f
 /* Table overflow policy. */
 
-/* Chooses and returns a rule to evict from 'table'.  Returns NULL if the table
- * is not configured to evict rules or if the table contains no evictable
- * rules.  (Rules with 'evictable' set to false or with no timeouts are not
- * evictable.) */
-static struct rule *
-choose_rule_to_evict(struct oftable *table)
+/* Chooses and updates 'rulep' with a rule to evict from 'table'.  Sets 'rulep'
+ * to NULL if the table is not configured to evict rules or if the table
+ * contains no evictable rules.  (Rules with a readlock on their evict rwlock,
+ * or with no timeouts are not evictable.) */
+static bool
+choose_rule_to_evict(struct oftable *table, struct rule **rulep)
 {
     struct eviction_group *evg;
 
+    *rulep = NULL;
     if (!table->eviction_fields) {
-        return NULL;
+        return false;
     }
 
     /* In the common case, the outer and inner loops here will each be entered
@@ -5089,18 +5371,19 @@ choose_rule_to_evict(struct oftable *table)
      *     group has no evictable rules.
      *
      *   - The outer loop can exit only if table's 'max_flows' is all filled up
-     *     by unevictable rules'. */
+     *     by unevictable rules. */
     HEAP_FOR_EACH (evg, size_node, &table->eviction_groups_by_size) {
         struct rule *rule;
 
         HEAP_FOR_EACH (rule, evg_node, &evg->rules) {
-            if (rule->evictable) {
-                return rule;
+            if (!ovs_rwlock_trywrlock(&rule->rwlock)) {
+                *rulep = rule;
+                return true;
             }
         }
     }
 
-    return NULL;
+    return false;
 }
 
 /* Searches 'ofproto' for tables that have more flows than their configured
@@ -5129,15 +5412,19 @@ ofproto_evict(struct ofproto *ofproto)
                 break;
             }
 
-            rule = choose_rule_to_evict(table);
-            if (!rule || rule->pending) {
+            if (!choose_rule_to_evict(table, &rule)) {
+                break;
+            }
+
+            if (rule->pending) {
+                ovs_rwlock_unlock(&rule->rwlock);
                 break;
             }
 
             ofoperation_create(group, rule,
                                OFOPERATION_DELETE, OFPRR_EVICTION);
             oftable_remove_rule(rule);
-            ofproto->ofproto_class->rule_destruct(rule);
+            ofproto->ofproto_class->rule_delete(rule);
         }
     }
     ofopgroup_submit(group);
@@ -5437,12 +5724,10 @@ oftable_enable_eviction(struct oftable *table,
 /* Removes 'rule' from the oftable that contains it. */
 static void
 oftable_remove_rule__(struct ofproto *ofproto, struct classifier *cls,
-                      struct rule *rule) OVS_REQ_WRLOCK(cls->rwlock)
+                      struct rule *rule)
+    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);
@@ -5452,7 +5737,9 @@ 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);
 }
 
 static void
@@ -5466,15 +5753,13 @@ oftable_remove_rule(struct rule *rule)
     ovs_rwlock_unlock(&table->cls.rwlock);
 }
 
-/* Inserts 'rule' into its oftable.  Removes any existing rule from 'rule''s
- * oftable that has an identical cls_rule.  Returns the rule that was removed,
- * if any, and otherwise NULL. */
-static struct rule *
-oftable_replace_rule(struct rule *rule)
+/* Inserts 'rule' into its oftable, which must not already contain any rule for
+ * the same cls_rule. */
+static void
+oftable_insert_rule(struct rule *rule)
 {
     struct ofproto *ofproto = rule->ofproto;
     struct oftable *table = &ofproto->tables[rule->table_id];
-    struct rule *victim;
     bool may_expire;
 
     ovs_mutex_lock(&rule->timeout_mutex);
@@ -5492,34 +5777,9 @@ oftable_replace_rule(struct rule *rule)
         list_insert(&meter->rules, &rule->meter_list_node);
     }
     ovs_rwlock_wrlock(&table->cls.rwlock);
-    victim = rule_from_cls_rule(classifier_replace(&table->cls, &rule->cr));
+    classifier_insert(&table->cls, &rule->cr);
     ovs_rwlock_unlock(&table->cls.rwlock);
-    if (victim) {
-        if (victim->meter_id) {
-            list_remove(&victim->meter_list_node);
-        }
-        cookies_remove(ofproto, victim);
-
-        ovs_mutex_lock(&ofproto->expirable_mutex);
-        if (!list_is_empty(&victim->expirable)) {
-            list_remove(&victim->expirable);
-        }
-        ovs_mutex_unlock(&ofproto->expirable_mutex);
-        eviction_group_remove_rule(victim);
-    }
     eviction_group_add_rule(rule);
-    return victim;
-}
-
-/* Removes 'old' from its oftable then, if 'new' is nonnull, inserts 'new'. */
-static void
-oftable_substitute_rule(struct rule *old, struct rule *new)
-{
-    if (new) {
-        oftable_replace_rule(new);
-    } else {
-        oftable_remove_rule(old);
-    }
 }
 \f
 /* unixctl commands. */