| Message ID | 20241008094320.3340980-1-vladimir.oltean@nxp.com (mailing list archive) |
|---|---|
| State | Accepted |
| Commit | 8c924369cb56c3054dca504c2c9c3eb208272865 |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | [net] net: dsa: refuse cross-chip mirroring operations | expand |
On Tue, Oct 08, 2024 at 12:43:20PM +0300, Vladimir Oltean wrote: > 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@nxp.com> Reviewed-by: Andrew Lunn <andrew@lunn.ch> Andrew
Hello: This patch was applied to netdev/net.git (main) by Jakub Kicinski <kuba@kernel.org>: On Tue, 8 Oct 2024 12:43:20 +0300 you wrote: > 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. > > [...] Here is the summary with links: - [net] net: dsa: refuse cross-chip mirroring operations https://git.kernel.org/netdev/net/c/8c924369cb56 You are awesome, thank you!
diff --git a/net/dsa/user.c b/net/dsa/user.c index 74eda9b30608..64f660d2334b 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;
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@nxp.com> --- This is a resubmission of: https://lore.kernel.org/netdev/20240913152915.2981126-5-vladimir.oltean@nxp.com/ with rewritten commit message and targetting the 'net' tree, as preparation for submitting the rest as 'net-next' material. net/dsa/user.c | 11 ++++++++--- 1 file changed, 8 insertions(+), 3 deletions(-)