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authorAlex Wang <alexw@nicira.com>2014-06-30 20:30:29 -0700
committerPravin B Shelar <pshelar@nicira.com>2014-06-30 20:47:15 -0700
commit4a46b24e147dfa9b858026da02cad0bdd4e149d2 (patch)
tree0a36962df76d37c1f44bfb683991848b7e23ed07
parentad55200734c65a3ec5d0c39d6ea904008baea536 (diff)
downloadlinux-4a46b24e147dfa9b858026da02cad0bdd4e149d2.tar.bz2
openvswitch: Use exact lookup for flow_get and flow_del.
Due to the race condition in userspace, there is chance that two overlapping megaflows could be installed in datapath. And this causes userspace unable to delete the less inclusive megaflow flow even after it timeout, since the flow_del logic will stop at the first match of masked flow. This commit fixes the bug by making the kernel flow_del and flow_get logic check all masks in that case. Introduced by 03f0d916a (openvswitch: Mega flow implementation). Signed-off-by: Alex Wang <alexw@nicira.com> Acked-by: Andy Zhou <azhou@nicira.com> Signed-off-by: Pravin B Shelar <pshelar@nicira.com>
-rw-r--r--net/openvswitch/datapath.c23
-rw-r--r--net/openvswitch/flow_table.c16
-rw-r--r--net/openvswitch/flow_table.h3
3 files changed, 29 insertions, 13 deletions
diff --git a/net/openvswitch/datapath.c b/net/openvswitch/datapath.c
index a863678c50ac..9db4bf6740d1 100644
--- a/net/openvswitch/datapath.c
+++ b/net/openvswitch/datapath.c
@@ -889,8 +889,11 @@ static int ovs_flow_cmd_new(struct sk_buff *skb, struct genl_info *info)
}
/* The unmasked key has to be the same for flow updates. */
if (unlikely(!ovs_flow_cmp_unmasked_key(flow, &match))) {
- error = -EEXIST;
- goto err_unlock_ovs;
+ flow = ovs_flow_tbl_lookup_exact(&dp->table, &match);
+ if (!flow) {
+ error = -ENOENT;
+ goto err_unlock_ovs;
+ }
}
/* Update actions. */
old_acts = ovsl_dereference(flow->sf_acts);
@@ -981,16 +984,12 @@ static int ovs_flow_cmd_set(struct sk_buff *skb, struct genl_info *info)
goto err_unlock_ovs;
}
/* Check that the flow exists. */
- flow = ovs_flow_tbl_lookup(&dp->table, &key);
+ flow = ovs_flow_tbl_lookup_exact(&dp->table, &match);
if (unlikely(!flow)) {
error = -ENOENT;
goto err_unlock_ovs;
}
- /* The unmasked key has to be the same for flow updates. */
- if (unlikely(!ovs_flow_cmp_unmasked_key(flow, &match))) {
- error = -EEXIST;
- goto err_unlock_ovs;
- }
+
/* Update actions, if present. */
if (likely(acts)) {
old_acts = ovsl_dereference(flow->sf_acts);
@@ -1063,8 +1062,8 @@ static int ovs_flow_cmd_get(struct sk_buff *skb, struct genl_info *info)
goto unlock;
}
- flow = ovs_flow_tbl_lookup(&dp->table, &key);
- if (!flow || !ovs_flow_cmp_unmasked_key(flow, &match)) {
+ flow = ovs_flow_tbl_lookup_exact(&dp->table, &match);
+ if (!flow) {
err = -ENOENT;
goto unlock;
}
@@ -1113,8 +1112,8 @@ static int ovs_flow_cmd_del(struct sk_buff *skb, struct genl_info *info)
goto unlock;
}
- flow = ovs_flow_tbl_lookup(&dp->table, &key);
- if (unlikely(!flow || !ovs_flow_cmp_unmasked_key(flow, &match))) {
+ flow = ovs_flow_tbl_lookup_exact(&dp->table, &match);
+ if (unlikely(!flow)) {
err = -ENOENT;
goto unlock;
}
diff --git a/net/openvswitch/flow_table.c b/net/openvswitch/flow_table.c
index 574c3abc9b30..cf2d853646f0 100644
--- a/net/openvswitch/flow_table.c
+++ b/net/openvswitch/flow_table.c
@@ -456,6 +456,22 @@ struct sw_flow *ovs_flow_tbl_lookup(struct flow_table *tbl,
return ovs_flow_tbl_lookup_stats(tbl, key, &n_mask_hit);
}
+struct sw_flow *ovs_flow_tbl_lookup_exact(struct flow_table *tbl,
+ struct sw_flow_match *match)
+{
+ struct table_instance *ti = rcu_dereference_ovsl(tbl->ti);
+ struct sw_flow_mask *mask;
+ struct sw_flow *flow;
+
+ /* Always called under ovs-mutex. */
+ list_for_each_entry(mask, &tbl->mask_list, list) {
+ flow = masked_flow_lookup(ti, match->key, mask);
+ if (flow && ovs_flow_cmp_unmasked_key(flow, match)) /* Found */
+ return flow;
+ }
+ return NULL;
+}
+
int ovs_flow_tbl_num_masks(const struct flow_table *table)
{
struct sw_flow_mask *mask;
diff --git a/net/openvswitch/flow_table.h b/net/openvswitch/flow_table.h
index ca8a5820f615..5918bff7f3f6 100644
--- a/net/openvswitch/flow_table.h
+++ b/net/openvswitch/flow_table.h
@@ -76,7 +76,8 @@ struct sw_flow *ovs_flow_tbl_lookup_stats(struct flow_table *,
u32 *n_mask_hit);
struct sw_flow *ovs_flow_tbl_lookup(struct flow_table *,
const struct sw_flow_key *);
-
+struct sw_flow *ovs_flow_tbl_lookup_exact(struct flow_table *tbl,
+ struct sw_flow_match *match);
bool ovs_flow_cmp_unmasked_key(const struct sw_flow *flow,
struct sw_flow_match *match);