Commit e358bef7 authored Nov 03, 2020 by Vladimir Oltean Committed by Jakub Kicinski Nov 05, 2020

net: dsa: Give drivers the chance to veto certain upper devices



Some switches rely on unique pvids to ensure port separation in
standalone mode, because they don't have a port forwarding matrix
configurable in hardware. So, setups like a group of 2 uppers with the
same VLAN, swp0.100 and swp1.100, will cause traffic tagged with VLAN
100 to be autonomously forwarded between these switch ports, in spite
of there being no bridge between swp0 and swp1.

These drivers need to prevent this from happening. They need to have
VLAN filtering enabled in standalone mode (so they'll drop frames tagged
with unknown VLANs) and they can only accept an 8021q upper on a port as
long as it isn't installed on any other port too. So give them the
chance to veto bad user requests.

Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
[Kurt: Pass info instead of ptr]
Signed-off-by: Kurt Kanzenbach <kurt@linutronix.de>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

parent 01ef09ca

include/net/dsa.h

+6 −0

Original line number	Diff line number	Diff line
		@@ -536,6 +536,12 @@ struct dsa_switch_ops {
		void (get_regs)(struct dsa_switch ds, int port,
		struct ethtool_regs regs, void p);

		/*
		* Upper device tracking.
		*/
		int (port_prechangeupper)(struct dsa_switch ds, int port,
		struct netdev_notifier_changeupper_info *info);

		/*
		* Bridge integration
		*/

net/dsa/slave.c

+12 −0

Original line number	Diff line number	Diff line
		@@ -2032,10 +2032,22 @@ static int dsa_slave_netdevice_event(struct notifier_block *nb,
		switch (event) {
		case NETDEV_PRECHANGEUPPER: {
		struct netdev_notifier_changeupper_info *info = ptr;
		struct dsa_switch *ds;
		struct dsa_port *dp;
		int err;

		if (!dsa_slave_dev_check(dev))
		return dsa_prevent_bridging_8021q_upper(dev, ptr);

		dp = dsa_slave_to_port(dev);
		ds = dp->ds;

		if (ds->ops->port_prechangeupper) {
		err = ds->ops->port_prechangeupper(ds, dp->index, info);
		if (err)
		return notifier_from_errno(err);
		}

		if (is_vlan_dev(info->upper_dev))
		return dsa_slave_check_8021q_upper(dev, ptr);
		break;

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