I found the latest net-next kernel calls dsa_slave_port_obj_del() multiple times,
one for each port, with host port as the parameter.
As the base driver cannot find an entry with that host port, it returns an error
and so users will see a lot of failures from the DSA switch.
Is this a new behavior and the driver needs to handle that? In previous versions
I do not think I saw that.
Typical operation is a PC connected to a port in a switch wants to send multicast
packets. It broadcasts an IGMP membership join message. Function
dsa_slave_port_obj_add is called to setup an entry in the lookup table. When
IGMP membership leave message is received dsa_slave_port_obj_del will be
called after a delay. But then it is called for each port with host port as the
parameter.
Another issue is the host port can setup an entry for IPv6 neighbor discovery like
33:33:FF:??:??:??. When it leaves a failure message will be displayed for lan2,
lan3, and so on. It seems the first deletion is coming from lan1.
On Wed, Dec 06, 2017 at 02:33:07AM +0000, Tristram.Ha@microchip.com wrote:
I found the latest net-next kernel calls dsa_slave_port_obj_del() multiple times,
one for each port, with host port as the parameter.
Hi Tristram
SWITCHDEV_OBJ_ID_HOST_MDB is used, when there is a join/leave on the
bridge interface. It happens for each interface in the bridge, and it
means, packets which match the group that ingress on that interface
should be forwarded to the CPU.
As the base driver cannot find an entry with that host port, it returns an error
and so users will see a lot of failures from the DSA switch.
You have a few options:
1) Just forward all multicast traffic to the cpu, and ignore
SWITCHDEV_OBJ_ID_HOST_MDB.
2) Implement SWITCHDEV_OBJ_ID_HOST_MDB so you setup your tables to
just forward the requested multicast to the cpu.
3) You can also forward a bit too much, e.g. if you cannot set filters
per ingress port, just send all the traffic for the group from any
port.
The bridge will discard whatever it does not need.
Is this a new behavior and the driver needs to handle that? In previous versions
I do not think I saw that.
SWITCHDEV_OBJ_ID_HOST_MDB is new. However, dsa_slave_port_obj_del()
can be called for all sorts of objects, and you should only be
reacting on those your support. So adding a new object should not of
changed anything.
Typical operation is a PC connected to a port in a switch wants to send multicast
packets. It broadcasts an IGMP membership join message. Function
dsa_slave_port_obj_add is called to setup an entry in the lookup table. When
IGMP membership leave message is received dsa_slave_port_obj_del will be
called after a delay. But then it is called for each port with host port as the
parameter.
Correct. switchdev is a generic API. It also needs to work for Top of
Rack switches, which generally have a match/action architecture. I can
imagine that this match/action happens per port, so we need to call
switchdev per port. However, switches supported by DSA tend to have
central management of all ports, so one call would be sufficient. With
a DSA driver, you just need to expect redundant calls, and do the
right thing.
Andrew
SWITCHDEV_OBJ_ID_HOST_MDB is used, when there is a join/leave on the
bridge interface. It happens for each interface in the bridge, and it
means, packets which match the group that ingress on that interface
should be forwarded to the CPU.
quoted
As the base driver cannot find an entry with that host port, it returns an
error
quoted
and so users will see a lot of failures from the DSA switch.
You have a few options:
1) Just forward all multicast traffic to the cpu, and ignore
SWITCHDEV_OBJ_ID_HOST_MDB.
2) Implement SWITCHDEV_OBJ_ID_HOST_MDB so you setup your tables to
just forward the requested multicast to the cpu.
3) You can also forward a bit too much, e.g. if you cannot set filters
per ingress port, just send all the traffic for the group from any
port.
The bridge will discard whatever it does not need.
quoted
Is this a new behavior and the driver needs to handle that? In previous
versions
quoted
I do not think I saw that.
SWITCHDEV_OBJ_ID_HOST_MDB is new. However,
dsa_slave_port_obj_del()
can be called for all sorts of objects, and you should only be
reacting on those your support. So adding a new object should not of
changed anything.
quoted
Typical operation is a PC connected to a port in a switch wants to send
multicast
quoted
packets. It broadcasts an IGMP membership join message. Function
dsa_slave_port_obj_add is called to setup an entry in the lookup table.
When
quoted
IGMP membership leave message is received dsa_slave_port_obj_del will
be
quoted
called after a delay. But then it is called for each port with host port as the
parameter.
Correct. switchdev is a generic API. It also needs to work for Top of
Rack switches, which generally have a match/action architecture. I can
imagine that this match/action happens per port, so we need to call
switchdev per port. However, switches supported by DSA tend to have
central management of all ports, so one call would be sufficient. With
a DSA driver, you just need to expect redundant calls, and do the
right thing.
The base DSA driver only knows about port_mdb_add and port_mdb_del.
It does not really know about SWITCHDEV_OBJ_ID_HOST_MDB.
It is fine to use port_mdb_add and port_mdb_del for
SWITCHDEV_OBJ_ID_HOST_MDB as hardware can program an entry for
the host port, but receiving many port_mdb_del calls with the same
parameter makes it difficult to handle. Example:
port_mdb_add 2 xx:xx:xx:xx:xx:xx
port_mdb_del 2 xx:xx:xx:xx:xx:xx
port_mdb_del 4 xx:xx:xx:xx:xx:xx; lan1
port_mdb_del 4 xx:xx:xx:xx:xx:xx; lan2
port_mdb_del 4 xx:xx:xx:xx:xx:xx; lan3
There is no indication in the port_mdb_del call to show this call is for
port 1, 2, and so on.
port_mdb_add can be used to add an entry for the host. Again it is
called as many times as number of ports. I think the port_mdb_* call
needs an extra parameter to make it useful in this situation.
An easy fix is not to return any error in port_mdb_del, or ignore host port.
It seems port_mdb_prepare is used to indicate an entry can be added
before the actual port_mdb_add call, which returns void and so cannot
indicate failure to add. Currently there is no implementation for that
port_mdb_prepare call and the Marvell driver just displays a warning
inside its port_mdb_add function.