[ovs-dev,v2] ofproto-dpif-xlate: Do not use zero-weight buckets in select groups.
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Message ID 20190607232824.23360-1-blp@ovn.org
State New
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  • [ovs-dev,v2] ofproto-dpif-xlate: Do not use zero-weight buckets in select groups.
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Commit Message

Ben Pfaff June 7, 2019, 11:28 p.m. UTC
The OpenFlow specification says that buckets in select groups with a weight
of zero should not be selected, but the ofproto-dpif implementation could
select them in corner cases.  This fixes the problem.

Reported-by: ychen <ychen103103@163.com>
Reported-at: https://mail.openvswitch.org/pipermail/ovs-dev/2019-May/359349.html
Signed-off-by: Ben Pfaff <blp@ovn.org>
---
v1->v2: Simplify and fix figuring out whether a group is alive.

 ofproto/ofproto-dpif-xlate.c | 18 ++++++++++++------
 1 file changed, 12 insertions(+), 6 deletions(-)

Patch
diff mbox series

diff --git a/ofproto/ofproto-dpif-xlate.c b/ofproto/ofproto-dpif-xlate.c
index 04d69ed06c20..1ace92d22019 100644
--- a/ofproto/ofproto-dpif-xlate.c
+++ b/ofproto/ofproto-dpif-xlate.c
@@ -1,4 +1,4 @@ 
-/* Copyright (c) 2009, 2010, 2011, 2012, 2013, 2014, 2015, 2016, 2017 Nicira, Inc.
+/* Copyright (c) 2009, 2010, 2011, 2012, 2013, 2014, 2015, 2016, 2017, 2019 Nicira, Inc.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -1864,8 +1864,8 @@  group_is_alive(const struct xlate_ctx *ctx, uint32_t group_id, int depth)
 #define MAX_LIVENESS_RECURSION 128 /* Arbitrary limit */
 
 static bool
-bucket_is_alive(const struct xlate_ctx *ctx,
-                struct ofputil_bucket *bucket, int depth)
+bucket_is_alive(const struct xlate_ctx *ctx, const struct group_dpif *group,
+                const struct ofputil_bucket *bucket, int depth)
 {
     if (depth >= MAX_LIVENESS_RECURSION) {
         xlate_report_error(ctx, "bucket chaining exceeded %d links",
@@ -1873,6 +1873,12 @@  bucket_is_alive(const struct xlate_ctx *ctx,
         return false;
     }
 
+    /* In "select" groups, buckets with weight 0 are not used.
+     * In other kinds of groups, weight does not matter. */
+    if (group->up.type == OFPGT11_SELECT && bucket->weight == 0) {
+        return false;
+    }
+
     return (!ofputil_bucket_has_liveness(bucket)
             || (bucket->watch_port != OFPP_ANY
                && odp_port_is_alive(ctx, bucket->watch_port))
@@ -1910,7 +1916,7 @@  group_first_live_bucket(const struct xlate_ctx *ctx,
 {
     struct ofputil_bucket *bucket;
     LIST_FOR_EACH (bucket, list_node, &group->up.buckets) {
-        if (bucket_is_alive(ctx, bucket, depth)) {
+        if (bucket_is_alive(ctx, group, bucket, depth)) {
             return bucket;
         }
         xlate_report_bucket_not_live(ctx, bucket);
@@ -1929,7 +1935,7 @@  group_best_live_bucket(const struct xlate_ctx *ctx,
 
     struct ofputil_bucket *bucket;
     LIST_FOR_EACH (bucket, list_node, &group->up.buckets) {
-        if (bucket_is_alive(ctx, bucket, 0)) {
+        if (bucket_is_alive(ctx, group, bucket, 0)) {
             uint32_t score =
                 (hash_int(bucket->bucket_id, basis) & 0xffff) * bucket->weight;
             if (score >= best_score) {
@@ -4535,7 +4541,7 @@  pick_dp_hash_select_group(struct xlate_ctx *ctx, struct group_dpif *group)
         for (int i = 0; i <= hash_mask; i++) {
             struct ofputil_bucket *b =
                     group->hash_map[(dp_hash + i) & hash_mask];
-            if (bucket_is_alive(ctx, b, 0)) {
+            if (bucket_is_alive(ctx, group, b, 0)) {
                 return b;
             }
         }