6.11-stable review patch. If anyone has any objections, please let me know.
------------------
From: Vladimir Oltean <vladimir.oltean@xxxxxxx>
[ Upstream commit 8c924369cb56c3054dca504c2c9c3eb208272865 ]
In case of a tc mirred action from one switch to another, the behavior
is not correct. We simply tell the source switch driver to program a
mirroring entry towards mirror->to_local_port = to_dp->index, but it is
not even guaranteed that the to_dp belongs to the same switch as dp.
For proper cross-chip support, we would need to go through the
cross-chip notifier layer in switch.c, program the entry on cascade
ports, and introduce new, explicit API for cross-chip mirroring, given
that intermediary switches should have introspection into the DSA tags
passed through the cascade port (and not just program a port mirror on
the entire cascade port). None of that exists today.
Reject what is not implemented so that user space is not misled into
thinking it works.
Fixes: f50f212749e8 ("net: dsa: Add plumbing for port mirroring")
Signed-off-by: Vladimir Oltean <vladimir.oltean@xxxxxxx>
Reviewed-by: Andrew Lunn <andrew@xxxxxxx>
Link: https://patch.msgid.link/20241008094320.3340980-1-vladimir.oltean@xxxxxxx
Signed-off-by: Jakub Kicinski <kuba@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
net/dsa/user.c | 11 ++++++++---
1 file changed, 8 insertions(+), 3 deletions(-)
diff --git a/net/dsa/user.c b/net/dsa/user.c
index f5adfa1d978a2..ac34d5d1deb09 100644
--- a/net/dsa/user.c
+++ b/net/dsa/user.c
@@ -1392,6 +1392,14 @@ dsa_user_add_cls_matchall_mirred(struct net_device *dev,
if (!dsa_user_dev_check(act->dev))
return -EOPNOTSUPP;
+ to_dp = dsa_user_to_port(act->dev);
+
+ if (dp->ds != to_dp->ds) {
+ NL_SET_ERR_MSG_MOD(extack,
+ "Cross-chip mirroring not implemented");
+ return -EOPNOTSUPP;
+ }
+
mall_tc_entry = kzalloc(sizeof(*mall_tc_entry), GFP_KERNEL);
if (!mall_tc_entry)
return -ENOMEM;
@@ -1399,9 +1407,6 @@ dsa_user_add_cls_matchall_mirred(struct net_device *dev,
mall_tc_entry->cookie = cls->cookie;
mall_tc_entry->type = DSA_PORT_MALL_MIRROR;
mirror = &mall_tc_entry->mirror;
-
- to_dp = dsa_user_to_port(act->dev);
-
mirror->to_local_port = to_dp->index;
mirror->ingress = ingress;
--
2.43.0
