From: Victor Nogueira <victor@mojatatu.com>
Date: Wed, 24 Jan 2024 15:34:56 +0000 (-0300)
Subject: tc: Add NLM_F_ECHO support for filters
X-Git-Tag: v6.9.0~32^2~15^2
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=cf0eae9a9fc4a40e98bac883919dc872244ee570;p=thirdparty%2Fiproute2.git

tc: Add NLM_F_ECHO support for filters

If the user specifies this flag for a filter command the kernel will
return the command's result back to user space.
For example:

  tc -echo filter add dev lo parent ffff: protocol ip matchall action ok

  added filter dev lo parent ffff: protocol ip pref 49152 matchall chain 0

As illustrated above, the kernel will give us a pref of 491252

The same can be done for other filter commands (replace, delete, and
change). For example:

  tc -echo filter del dev lo parent ffff: pref 49152 protocol ip matchall

  deleted filter dev lo parent ffff: protocol ip pref 49152 matchall chain 0

Signed-off-by: Victor Nogueira <victor@mojatatu.com>
Reviewed-by: Hangbin Liu <liuhangbin@gmail.com>
Signed-off-by: David Ahern <dsahern@kernel.org>
---

diff --git a/tc/tc_filter.c b/tc/tc_filter.c
index eb45c588..54790ddc 100644
--- a/tc/tc_filter.c
+++ b/tc/tc_filter.c
@@ -76,6 +76,7 @@ static int tc_filter_modify(int cmd, unsigned int flags, int argc, char **argv)
 	char  d[IFNAMSIZ] = {};
 	char  k[FILTER_NAMESZ] = {};
 	struct tc_estimator est = {};
+	int ret;
 
 	if (cmd == RTM_NEWTFILTER && flags & NLM_F_CREATE)
 		protocol = htons(ETH_P_ALL);
@@ -221,7 +222,12 @@ static int tc_filter_modify(int cmd, unsigned int flags, int argc, char **argv)
 	if (est.ewma_log)
 		addattr_l(&req.n, sizeof(req), TCA_RATE, &est, sizeof(est));
 
-	if (rtnl_talk(&rth, &req.n, NULL) < 0) {
+	if (echo_request)
+		ret = rtnl_echo_talk(&rth, &req.n, json, print_filter);
+	else
+		ret = rtnl_talk(&rth, &req.n, NULL);
+
+	if (ret < 0) {
 		fprintf(stderr, "We have an error talking to the kernel\n");
 		return 2;
 	}