Use netlink_has_listeners() and NLM_F_ECHO flag to determine if a
reply is needed or not for OVS_FLOW_CMD_NEW, OVS_FLOW_CMD_SET, or
OVS_FLOW_CMD_DEL.
Note: This may need compat support for older kernels.
Signed-off-by: Jarno Rajahalme <jrajaha...@nicira.com>
---
datapath/datapath.c | 56 +++++++++++++++++++++++++++++++++++----------------
1 file changed, 39 insertions(+), 17 deletions(-)
diff --git a/datapath/datapath.c b/datapath/datapath.c
index 59b7f3f..60c94ac 100644
--- a/datapath/datapath.c
+++ b/datapath/datapath.c
@@ -64,6 +64,15 @@
int ovs_net_id __read_mostly;
+/* Check if need to build a reply message.
+ * OVS userspace sets the NLM_F_ECHO flag if it needs the reply. */
+static bool ovs_must_build_reply(struct genl_info *info,
+ const struct genl_multicast_group *grp)
+{
+ return info->nlhdr->nlmsg_flags & NLM_F_ECHO ||
+ netlink_has_listeners(genl_info_net(info)->genl_sock, grp->id);
+}
+
static void ovs_notify(struct sk_buff *skb, struct genl_info *info,
struct genl_multicast_group *grp)
{
@@ -782,7 +791,7 @@ static int ovs_flow_cmd_new_or_set(struct sk_buff *skb,
struct genl_info *info)
struct sw_flow_key key, masked_key;
struct sw_flow *flow = NULL;
struct sw_flow_mask mask;
- struct sk_buff *reply;
+ struct sk_buff *reply = NULL;
struct datapath *dp;
struct sw_flow_actions *acts = NULL;
struct sw_flow_match match;
@@ -857,7 +866,9 @@ static int ovs_flow_cmd_new_or_set(struct sk_buff *skb,
struct genl_info *info)
goto err_flow_free;
}
- reply = ovs_flow_cmd_build_info(flow, dp, info,
OVS_FLOW_CMD_NEW);
+ if (ovs_must_build_reply(info, &ovs_dp_flow_multicast_group))
+ reply = ovs_flow_cmd_build_info(flow, dp, info,
+ OVS_FLOW_CMD_NEW);
} else {
/* We found a matching flow. */
struct sw_flow_actions *old_acts;
@@ -882,7 +893,9 @@ static int ovs_flow_cmd_new_or_set(struct sk_buff *skb,
struct genl_info *info)
rcu_assign_pointer(flow->sf_acts, acts);
ovs_nla_free_flow_actions(old_acts);
- reply = ovs_flow_cmd_build_info(flow, dp, info,
OVS_FLOW_CMD_NEW);
+ if (ovs_must_build_reply(info, &ovs_dp_flow_multicast_group))
+ reply = ovs_flow_cmd_build_info(flow, dp, info,
+ OVS_FLOW_CMD_NEW);
/* Clear stats. */
if (a[OVS_FLOW_ATTR_CLEAR])
@@ -890,11 +903,14 @@ static int ovs_flow_cmd_new_or_set(struct sk_buff *skb,
struct genl_info *info)
}
ovs_unlock();
- if (!IS_ERR(reply))
- ovs_notify(reply, info, &ovs_dp_flow_multicast_group);
- else
- netlink_set_err(sock_net(skb->sk)->genl_sock, 0,
- ovs_dp_flow_multicast_group.id, PTR_ERR(reply));
+ if (reply) {
+ if (!IS_ERR(reply))
+ ovs_notify(reply, info, &ovs_dp_flow_multicast_group);
+ else
+ netlink_set_err(sock_net(skb->sk)->genl_sock, 0,
+ ovs_dp_flow_multicast_group.id,
+ PTR_ERR(reply));
+ }
return 0;
err_flow_free:
@@ -959,7 +975,7 @@ static int ovs_flow_cmd_del(struct sk_buff *skb, struct
genl_info *info)
struct nlattr **a = info->attrs;
struct ovs_header *ovs_header = info->userhdr;
struct sw_flow_key key;
- struct sk_buff *reply;
+ struct sk_buff *reply = NULL;
struct sw_flow *flow;
struct datapath *dp;
struct sw_flow_match match;
@@ -988,22 +1004,28 @@ static int ovs_flow_cmd_del(struct sk_buff *skb, struct
genl_info *info)
goto unlock;
}
- reply = ovs_flow_cmd_alloc_info(flow, info);
- if (!reply) {
- err = -ENOMEM;
- goto unlock;
+ if (ovs_must_build_reply(info, &ovs_dp_flow_multicast_group)) {
+ reply = ovs_flow_cmd_alloc_info(flow, info);
+ if (!reply) {
+ err = -ENOMEM;
+ goto unlock;
+ }
}
ovs_flow_tbl_remove(&dp->table, flow);
- err = ovs_flow_cmd_fill_info(flow, dp, reply, info->snd_portid,
- info->snd_seq, 0, OVS_FLOW_CMD_DEL);
- BUG_ON(err < 0);
+ if (reply) {
+ err = ovs_flow_cmd_fill_info(flow, dp, reply, info->snd_portid,
+ info->snd_seq, 0,
+ OVS_FLOW_CMD_DEL);
+ BUG_ON(err < 0);
+ }
ovs_flow_free(flow, true);
ovs_unlock();
- ovs_notify(reply, info, &ovs_dp_flow_multicast_group);
+ if (reply)
+ ovs_notify(reply, info, &ovs_dp_flow_multicast_group);
return 0;
unlock:
ovs_unlock();
--
1.7.10.4
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