From: Phil Sutter <phil@nwl.cc>
Date: Wed, 13 May 2020 14:29:51 +0000 (+0200)
Subject: JSON: Improve performance of json_events_cb()
X-Git-Tag: v0.9.5~17
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=c96c7da272e33a34770c4de4e3e50f7ed264672e;p=thirdparty%2Fnftables.git

JSON: Improve performance of json_events_cb()

The function tries to insert handles into JSON input for echo option.
Yet there may be nothing to do if the given netlink message doesn't
contain a handle, e.g. if it is an 'add element' command. Calling
seqnum_to_json() is pointless overhead in that case, and if input is
large this overhead is significant. Better wait with that call until
after checking if the message is relevant at all.

Signed-off-by: Phil Sutter <phil@nwl.cc>
Acked-by: Eric Garver <eric@garver.life>
---

diff --git a/src/parser_json.c b/src/parser_json.c
index 4468407b..3a84bd96 100644
--- a/src/parser_json.c
+++ b/src/parser_json.c
@@ -3847,12 +3847,15 @@ static uint64_t handle_from_nlmsg(const struct nlmsghdr *nlh)
 }
 int json_events_cb(const struct nlmsghdr *nlh, struct netlink_mon_handler *monh)
 {
-	json_t *tmp, *json = seqnum_to_json(nlh->nlmsg_seq);
 	uint64_t handle = handle_from_nlmsg(nlh);
+	json_t *tmp, *json;
 	void *iter;
 
-	/* might be anonymous set, ignore message */
-	if (!json || !handle)
+	if (!handle)
+		return MNL_CB_OK;
+
+	json = seqnum_to_json(nlh->nlmsg_seq);
+	if (!json)
 		return MNL_CB_OK;
 
 	tmp = json_object_get(json, "add");