[ovs-dev] [flow monitor v2 10/12] ofproto: Represent flow cookie changes as operations too.

[Ben Pfaff]

An upcoming commit will add support for monitoring changes to the flow
table.  This feature wants to be able to report changes to flow cookies,
as well as to other properties of a flow.  Until now, however, a flow_mod
that modifies only the flow's cookie is treated as a special case that does
not go through the ofoperation mechanism.  That makes it harder to report
flow cookie-only changes (it would require an additional special case in
the reporting mechanism) so this commit changes cookie-only changes to
go through ofoperations.

The bulk of this change is to change the meaning of ofoperation's 'ofpacts'
member so that a NULL value indicates that the flow's actions are not
changing.  Otherwise a flow-cookie only change would still require copying
and then freeing all the actions, which seems like a waste.

Signed-off-by: Ben Pfaff <blp at nicira.com>
---
 ofproto/ofproto.c |   50 +++++++++++++++++++++++++++++++++-----------------
 1 files changed, 33 insertions(+), 17 deletions(-)

diff --git a/ofproto/ofproto.c b/ofproto/ofproto.c
index 66e8bb8..1fed0a7 100644
--- a/ofproto/ofproto.c
+++ b/ofproto/ofproto.c
@@ -118,9 +118,14 @@ struct ofoperation {
     struct hmap_node hmap_node; /* In ofproto's "deletions" hmap. */
     struct rule *rule;          /* Rule being operated upon. */
     enum ofoperation_type type; /* Type of operation. */
-    struct rule *victim;        /* OFOPERATION_ADD: Replaced rule. */
-    struct ofpact *ofpacts;     /* OFOPERATION_MODIFY: Replaced actions. */
-    size_t ofpacts_len;         /* OFOPERATION_MODIFY: Bytes of ofpacts. */
+
+    /* OFOPERATION_ADD. */
+    struct rule *victim;        /* Rule being replaced, if any.. */
+
+    /* OFOPERATION_MODIFY: The old actions, if the actions are changing. */
+    struct ofpact *ofpacts;
+    size_t ofpacts_len;
+
     ovs_be64 flow_cookie;       /* Rule's old flow cookie. */
     enum ofperr error;          /* 0 if no error. */
 };
@@ -2924,6 +2929,10 @@ modify_flows__(struct ofproto *ofproto, struct ofconn *ofconn,
     group = ofopgroup_create(ofproto, ofconn, request, fm->buffer_id);
     error = OFPERR_OFPBRC_EPERM;
     LIST_FOR_EACH (rule, ofproto_node, rules) {
+        struct ofoperation *op;
+        bool actions_changed;
+        ovs_be64 new_cookie;
+
         if (rule_is_modifiable(rule)) {
             /* At least one rule is modifiable, don't report EPERM error. */
             error = 0;
@@ -2931,21 +2940,26 @@ modify_flows__(struct ofproto *ofproto, struct ofconn *ofconn,
             continue;
         }
 
-        if (!ofpacts_equal(fm->ofpacts, fm->ofpacts_len,
-                           rule->ofpacts, rule->ofpacts_len)) {
-            struct ofoperation *op;
+        actions_changed = !ofpacts_equal(fm->ofpacts, fm->ofpacts_len,
+                                         rule->ofpacts, rule->ofpacts_len);
+        new_cookie = (fm->new_cookie != htonll(UINT64_MAX)
+                      ? fm->new_cookie
+                      : rule->flow_cookie);
+        if (!actions_changed && new_cookie == rule->flow_cookie) {
+            /* No change at all. */
+            continue;
+        }
 
-            op = ofoperation_create(group, rule, OFOPERATION_MODIFY);
+        op = ofoperation_create(group, rule, OFOPERATION_MODIFY);
+        rule->flow_cookie = new_cookie;
+        if (actions_changed) {
             op->ofpacts = rule->ofpacts;
-            op->ofpacts_len = rule->ofpacts_len;
+            op->ofpacts_len = op->ofpacts_len;
             rule->ofpacts = xmemdup(fm->ofpacts, fm->ofpacts_len);
             rule->ofpacts_len = fm->ofpacts_len;
             rule->ofproto->ofproto_class->rule_modify_actions(rule);
         } else {
-            rule->modified = time_msec();
-        }
-        if (fm->new_cookie != htonll(UINT64_MAX)) {
-            rule->flow_cookie = fm->new_cookie;
+            ofoperation_complete(op, 0);
         }
     }
     ofopgroup_submit(group);
@@ -3651,11 +3665,13 @@ ofopgroup_complete(struct ofopgroup *group)
                 rule->modified = time_msec();
             } else {
                 rule->flow_cookie = op->flow_cookie;
-                free(rule->ofpacts);
-                rule->ofpacts = op->ofpacts;
-                rule->ofpacts_len = op->ofpacts_len;
-                op->ofpacts = NULL;
-                op->ofpacts_len = 0;
+                if (op->ofpacts) {
+                    free(rule->ofpacts);
+                    rule->ofpacts = op->ofpacts;
+                    rule->ofpacts_len = op->ofpacts_len;
+                    op->ofpacts = NULL;
+                    op->ofpacts_len = 0;
+                }
             }
             break;
 
-- 
1.7.2.5