net: dsa: read mac address from DT for slave device

Message ID 20190222125815.12866-1-vkoul@kernel.org
State New
Headers show
Series
  • net: dsa: read mac address from DT for slave device
Related show

Commit Message

Vinod Koul Feb. 22, 2019, 12:58 p.m.
From: Xiaofei Shen <xiaofeis@codeaurora.org>


Before creating a slave netdevice, get the mac address from DTS and
apply in case it is valid.

Signed-off-by: Xiaofei Shen <xiaofeis@codeaurora.org>

Signed-off-by: Vinod Koul <vkoul@kernel.org>

---
 include/net/dsa.h | 1 +
 net/dsa/dsa2.c    | 1 +
 net/dsa/slave.c   | 5 ++++-
 3 files changed, 6 insertions(+), 1 deletion(-)

-- 
2.20.1

Comments

xiaofeis@codeaurora.org Feb. 25, 2019, 1:28 p.m. | #1
Hi Florian

We have two slave DSA interfaces, wan0 and lan0, one is for wan port,
and the other is for lan port. Customer has it's mac address pool, they 
want
to assign the mac address from the pool on wan0, lan0, and other 
interfaces like
wifi, bt. Coreboot/uboot will populate it to the DTS node, so the driver 
can
get it from it's node. For DSA slave interface, it already has it's own 
DTS node, it's
easy to just add one porperty "local-mac-address" there for the usage in 
DSA driver.

If not use DSA framework, normally we will use eth0.x and eth0.y for wan 
and lan.
On this case, customer usually also assign the MAC address on these 
logical interface
from it's pool.

On 2019-02-22 23:43, Florian Fainelli wrote:
> On 2/22/19 4:58 AM, Vinod Koul wrote:

>> From: Xiaofei Shen <xiaofeis@codeaurora.org>

>> 

>> Before creating a slave netdevice, get the mac address from DTS and

>> apply in case it is valid.

> 

> Can you explain your use case in details?

> 

> Assigning a MAC address to a network device that represents a switch

> port does not quite make sense in general. The switch port is really

> representing one end of a pipe, so one side you have stations and on 

> the

> other side, you have the CPU/management Ethernet MAC controller's MAC

> address which constitutes a station as well. The DSA slave network

> devices are just software constructs meant to steer traffic towards

> specific ports of the switch, but they are all from the perpsective of

> traffic reaching the CPU Port in the first place, therefore traffic 

> that

> is generally a known unicast Ethernet frame with the CPU's MAC address

> as MAC DA (and of course all types of unknown MC, management traffic 

> etc.)

> 

> By default, DSA switch need to come up in a configuration where all

> ports (except CPU/management) must be strictly separate from every 

> other

> port such that we can achieve what a standalone Ethernet NIC would do.

> This works because all ports are isolated from one another, so there is

> no cross talk and so having the same MAC address (the one from the CPU)

> on the DSA slave network devices just works, each port is a separate

> broadcast domain.

> 

> Once you start bridging one or ore ports, the bridge root port will 

> have

> a MAC address, most likely the one the CPU/management Ethernet MAC, but

> similarly, this is not an issue and that's exactly how a software 

> bridge

> would work as well.

> 

>> 

>> Signed-off-by: Xiaofei Shen <xiaofeis@codeaurora.org>

>> Signed-off-by: Vinod Koul <vkoul@kernel.org>

>> ---

>>  include/net/dsa.h | 1 +

>>  net/dsa/dsa2.c    | 1 +

>>  net/dsa/slave.c   | 5 ++++-

>>  3 files changed, 6 insertions(+), 1 deletion(-)

>> 

>> diff --git a/include/net/dsa.h b/include/net/dsa.h

>> index b3eefe8e18fd..aa24ce756679 100644

>> --- a/include/net/dsa.h

>> +++ b/include/net/dsa.h

>> @@ -198,6 +198,7 @@ struct dsa_port {

>>  	unsigned int		index;

>>  	const char		*name;

>>  	const struct dsa_port	*cpu_dp;

>> +	const char		*mac;

>>  	struct device_node	*dn;

>>  	unsigned int		ageing_time;

>>  	u8			stp_state;

>> diff --git a/net/dsa/dsa2.c b/net/dsa/dsa2.c

>> index a1917025e155..afb7d9fa42f6 100644

>> --- a/net/dsa/dsa2.c

>> +++ b/net/dsa/dsa2.c

>> @@ -261,6 +261,7 @@ static int dsa_port_setup(struct dsa_port *dp)

>>  	int err = 0;

>> 

>>  	memset(&dp->devlink_port, 0, sizeof(dp->devlink_port));

>> +	dp->mac = of_get_mac_address(dp->dn);

>> 

>>  	if (dp->type != DSA_PORT_TYPE_UNUSED)

>>  		err = devlink_port_register(ds->devlink, &dp->devlink_port,

>> diff --git a/net/dsa/slave.c b/net/dsa/slave.c

>> index a3fcc1d01615..8e64c4e947c6 100644

>> --- a/net/dsa/slave.c

>> +++ b/net/dsa/slave.c

>> @@ -1308,7 +1308,10 @@ int dsa_slave_create(struct dsa_port *port)

>>  	slave_dev->features = master->vlan_features | NETIF_F_HW_TC;

>>  	slave_dev->hw_features |= NETIF_F_HW_TC;

>>  	slave_dev->ethtool_ops = &dsa_slave_ethtool_ops;

>> -	eth_hw_addr_inherit(slave_dev, master);

>> +	if (port->mac && is_valid_ether_addr(port->mac))

>> +		ether_addr_copy(slave_dev->dev_addr, port->mac);

>> +	else

>> +		eth_hw_addr_inherit(slave_dev, master);

>>  	slave_dev->priv_flags |= IFF_NO_QUEUE;

>>  	slave_dev->netdev_ops = &dsa_slave_netdev_ops;

>>  	slave_dev->switchdev_ops = &dsa_slave_switchdev_ops;

>>
Florian Fainelli Feb. 25, 2019, 5:27 p.m. | #2
On 2/25/19 5:28 AM, xiaofeis@codeaurora.org wrote:
> Hi Florian

> 

> We have two slave DSA interfaces, wan0 and lan0, one is for wan port,

> and the other is for lan port. Customer has it's mac address pool, they

> want

> to assign the mac address from the pool on wan0, lan0, and other

> interfaces like

> wifi, bt. Coreboot/uboot will populate it to the DTS node, so the driver

> can

> get it from it's node. For DSA slave interface, it already has it's own

> DTS node, it's

> easy to just add one porperty "local-mac-address" there for the usage in

> DSA driver.

> 

> If not use DSA framework, normally we will use eth0.x and eth0.y for wan

> and lan.

> On this case, customer usually also assign the MAC address on these

> logical interface

> from it's pool.


OK, but this is not necessary per my previous explanation: the CPU <=>
WAN pipe is a separate broadcast domain (otherwise it is a security hole
since you exposing LAN machines to the outside world), and so there is
no need for a separate MAC address. It might be convenient to have one,
especially for the provider, if they run a management software (e.g.:
TR69), but it is not required per-se.

Let me ask a secondary question here, how many Ethernet MACs connect to
the switch in this configuration? Is there one that is supposed to be
assigned all LAN traffic and one that is supposed to be assigned all WAN
traffic? If so, then what you are doing makes even less

> 

> On 2019-02-22 23:43, Florian Fainelli wrote:

>> On 2/22/19 4:58 AM, Vinod Koul wrote:

>>> From: Xiaofei Shen <xiaofeis@codeaurora.org>

>>>

>>> Before creating a slave netdevice, get the mac address from DTS and

>>> apply in case it is valid.

>>

>> Can you explain your use case in details?

>>

>> Assigning a MAC address to a network device that represents a switch

>> port does not quite make sense in general. The switch port is really

>> representing one end of a pipe, so one side you have stations and on the

>> other side, you have the CPU/management Ethernet MAC controller's MAC

>> address which constitutes a station as well. The DSA slave network

>> devices are just software constructs meant to steer traffic towards

>> specific ports of the switch, but they are all from the perpsective of

>> traffic reaching the CPU Port in the first place, therefore traffic that

>> is generally a known unicast Ethernet frame with the CPU's MAC address

>> as MAC DA (and of course all types of unknown MC, management traffic

>> etc.)

>>

>> By default, DSA switch need to come up in a configuration where all

>> ports (except CPU/management) must be strictly separate from every other

>> port such that we can achieve what a standalone Ethernet NIC would do.

>> This works because all ports are isolated from one another, so there is

>> no cross talk and so having the same MAC address (the one from the CPU)

>> on the DSA slave network devices just works, each port is a separate

>> broadcast domain.

>>

>> Once you start bridging one or ore ports, the bridge root port will have

>> a MAC address, most likely the one the CPU/management Ethernet MAC, but

>> similarly, this is not an issue and that's exactly how a software bridge

>> would work as well.

>>

>>>

>>> Signed-off-by: Xiaofei Shen <xiaofeis@codeaurora.org>

>>> Signed-off-by: Vinod Koul <vkoul@kernel.org>

>>> ---

>>>  include/net/dsa.h | 1 +

>>>  net/dsa/dsa2.c    | 1 +

>>>  net/dsa/slave.c   | 5 ++++-

>>>  3 files changed, 6 insertions(+), 1 deletion(-)

>>>

>>> diff --git a/include/net/dsa.h b/include/net/dsa.h

>>> index b3eefe8e18fd..aa24ce756679 100644

>>> --- a/include/net/dsa.h

>>> +++ b/include/net/dsa.h

>>> @@ -198,6 +198,7 @@ struct dsa_port {

>>>      unsigned int        index;

>>>      const char        *name;

>>>      const struct dsa_port    *cpu_dp;

>>> +    const char        *mac;

>>>      struct device_node    *dn;

>>>      unsigned int        ageing_time;

>>>      u8            stp_state;

>>> diff --git a/net/dsa/dsa2.c b/net/dsa/dsa2.c

>>> index a1917025e155..afb7d9fa42f6 100644

>>> --- a/net/dsa/dsa2.c

>>> +++ b/net/dsa/dsa2.c

>>> @@ -261,6 +261,7 @@ static int dsa_port_setup(struct dsa_port *dp)

>>>      int err = 0;

>>>

>>>      memset(&dp->devlink_port, 0, sizeof(dp->devlink_port));

>>> +    dp->mac = of_get_mac_address(dp->dn);

>>>

>>>      if (dp->type != DSA_PORT_TYPE_UNUSED)

>>>          err = devlink_port_register(ds->devlink, &dp->devlink_port,

>>> diff --git a/net/dsa/slave.c b/net/dsa/slave.c

>>> index a3fcc1d01615..8e64c4e947c6 100644

>>> --- a/net/dsa/slave.c

>>> +++ b/net/dsa/slave.c

>>> @@ -1308,7 +1308,10 @@ int dsa_slave_create(struct dsa_port *port)

>>>      slave_dev->features = master->vlan_features | NETIF_F_HW_TC;

>>>      slave_dev->hw_features |= NETIF_F_HW_TC;

>>>      slave_dev->ethtool_ops = &dsa_slave_ethtool_ops;

>>> -    eth_hw_addr_inherit(slave_dev, master);

>>> +    if (port->mac && is_valid_ether_addr(port->mac))

>>> +        ether_addr_copy(slave_dev->dev_addr, port->mac);

>>> +    else

>>> +        eth_hw_addr_inherit(slave_dev, master);

>>>      slave_dev->priv_flags |= IFF_NO_QUEUE;

>>>      slave_dev->netdev_ops = &dsa_slave_netdev_ops;

>>>      slave_dev->switchdev_ops = &dsa_slave_switchdev_ops;

>>>



-- 
Florian
xiaofeis@codeaurora.org Feb. 26, 2019, 7:45 a.m. | #3
On 2019-02-26 01:27, Florian Fainelli wrote:
> On 2/25/19 5:28 AM, xiaofeis@codeaurora.org wrote:

>> Hi Florian

>> 

>> We have two slave DSA interfaces, wan0 and lan0, one is for wan port,

>> and the other is for lan port. Customer has it's mac address pool, 

>> they

>> want

>> to assign the mac address from the pool on wan0, lan0, and other

>> interfaces like

>> wifi, bt. Coreboot/uboot will populate it to the DTS node, so the 

>> driver

>> can

>> get it from it's node. For DSA slave interface, it already has it's 

>> own

>> DTS node, it's

>> easy to just add one porperty "local-mac-address" there for the usage 

>> in

>> DSA driver.

>> 

>> If not use DSA framework, normally we will use eth0.x and eth0.y for 

>> wan

>> and lan.

>> On this case, customer usually also assign the MAC address on these

>> logical interface

>> from it's pool.

> 

> OK, but this is not necessary per my previous explanation: the CPU <=>

> WAN pipe is a separate broadcast domain (otherwise it is a security 

> hole

> since you exposing LAN machines to the outside world), and so there is

> no need for a separate MAC address. It might be convenient to have one,

> especially for the provider, if they run a management software (e.g.:

> TR69), but it is not required per-se.

> 

> Let me ask a secondary question here, how many Ethernet MACs connect to

> the switch in this configuration? Is there one that is supposed to be

> assigned all LAN traffic and one that is supposed to be assigned all 

> WAN

> traffic? If so, then what you are doing makes even less

> 


Only one MAC connected to switch cpu port, both lan0 and wan0 are on the 
top of
same interface(eth0).

>> 

>> On 2019-02-22 23:43, Florian Fainelli wrote:

>>> On 2/22/19 4:58 AM, Vinod Koul wrote:

>>>> From: Xiaofei Shen <xiaofeis@codeaurora.org>

>>>> 

>>>> Before creating a slave netdevice, get the mac address from DTS and

>>>> apply in case it is valid.

>>> 

>>> Can you explain your use case in details?

>>> 

>>> Assigning a MAC address to a network device that represents a switch

>>> port does not quite make sense in general. The switch port is really

>>> representing one end of a pipe, so one side you have stations and on 

>>> the

>>> other side, you have the CPU/management Ethernet MAC controller's MAC

>>> address which constitutes a station as well. The DSA slave network

>>> devices are just software constructs meant to steer traffic towards

>>> specific ports of the switch, but they are all from the perpsective 

>>> of

>>> traffic reaching the CPU Port in the first place, therefore traffic 

>>> that

>>> is generally a known unicast Ethernet frame with the CPU's MAC 

>>> address

>>> as MAC DA (and of course all types of unknown MC, management traffic

>>> etc.)

>>> 

>>> By default, DSA switch need to come up in a configuration where all

>>> ports (except CPU/management) must be strictly separate from every 

>>> other

>>> port such that we can achieve what a standalone Ethernet NIC would 

>>> do.

>>> This works because all ports are isolated from one another, so there 

>>> is

>>> no cross talk and so having the same MAC address (the one from the 

>>> CPU)

>>> on the DSA slave network devices just works, each port is a separate

>>> broadcast domain.

>>> 

>>> Once you start bridging one or ore ports, the bridge root port will 

>>> have

>>> a MAC address, most likely the one the CPU/management Ethernet MAC, 

>>> but

>>> similarly, this is not an issue and that's exactly how a software 

>>> bridge

>>> would work as well.

>>> 

>>>> 

>>>> Signed-off-by: Xiaofei Shen <xiaofeis@codeaurora.org>

>>>> Signed-off-by: Vinod Koul <vkoul@kernel.org>

>>>> ---

>>>>  include/net/dsa.h | 1 +

>>>>  net/dsa/dsa2.c    | 1 +

>>>>  net/dsa/slave.c   | 5 ++++-

>>>>  3 files changed, 6 insertions(+), 1 deletion(-)

>>>> 

>>>> diff --git a/include/net/dsa.h b/include/net/dsa.h

>>>> index b3eefe8e18fd..aa24ce756679 100644

>>>> --- a/include/net/dsa.h

>>>> +++ b/include/net/dsa.h

>>>> @@ -198,6 +198,7 @@ struct dsa_port {

>>>>      unsigned int        index;

>>>>      const char        *name;

>>>>      const struct dsa_port    *cpu_dp;

>>>> +    const char        *mac;

>>>>      struct device_node    *dn;

>>>>      unsigned int        ageing_time;

>>>>      u8            stp_state;

>>>> diff --git a/net/dsa/dsa2.c b/net/dsa/dsa2.c

>>>> index a1917025e155..afb7d9fa42f6 100644

>>>> --- a/net/dsa/dsa2.c

>>>> +++ b/net/dsa/dsa2.c

>>>> @@ -261,6 +261,7 @@ static int dsa_port_setup(struct dsa_port *dp)

>>>>      int err = 0;

>>>> 

>>>>      memset(&dp->devlink_port, 0, sizeof(dp->devlink_port));

>>>> +    dp->mac = of_get_mac_address(dp->dn);

>>>> 

>>>>      if (dp->type != DSA_PORT_TYPE_UNUSED)

>>>>          err = devlink_port_register(ds->devlink, &dp->devlink_port,

>>>> diff --git a/net/dsa/slave.c b/net/dsa/slave.c

>>>> index a3fcc1d01615..8e64c4e947c6 100644

>>>> --- a/net/dsa/slave.c

>>>> +++ b/net/dsa/slave.c

>>>> @@ -1308,7 +1308,10 @@ int dsa_slave_create(struct dsa_port *port)

>>>>      slave_dev->features = master->vlan_features | NETIF_F_HW_TC;

>>>>      slave_dev->hw_features |= NETIF_F_HW_TC;

>>>>      slave_dev->ethtool_ops = &dsa_slave_ethtool_ops;

>>>> -    eth_hw_addr_inherit(slave_dev, master);

>>>> +    if (port->mac && is_valid_ether_addr(port->mac))

>>>> +        ether_addr_copy(slave_dev->dev_addr, port->mac);

>>>> +    else

>>>> +        eth_hw_addr_inherit(slave_dev, master);

>>>>      slave_dev->priv_flags |= IFF_NO_QUEUE;

>>>>      slave_dev->netdev_ops = &dsa_slave_netdev_ops;

>>>>      slave_dev->switchdev_ops = &dsa_slave_switchdev_ops;

>>>>
Florian Fainelli Feb. 27, 2019, 3:13 a.m. | #4
On 2/26/2019 6:04 PM, xiaofeis@codeaurora.org wrote:
> On 2019-02-26 15:45, xiaofeis@codeaurora.org wrote:

>> On 2019-02-26 01:27, Florian Fainelli wrote:

>>> On 2/25/19 5:28 AM, xiaofeis@codeaurora.org wrote:

>>>> Hi Florian

>>>>

>>>> We have two slave DSA interfaces, wan0 and lan0, one is for wan port,

>>>> and the other is for lan port. Customer has it's mac address pool, they

>>>> want

>>>> to assign the mac address from the pool on wan0, lan0, and other

>>>> interfaces like

>>>> wifi, bt. Coreboot/uboot will populate it to the DTS node, so the

>>>> driver

>>>> can

>>>> get it from it's node. For DSA slave interface, it already has it's own

>>>> DTS node, it's

>>>> easy to just add one porperty "local-mac-address" there for the

>>>> usage in

>>>> DSA driver.

>>>>

>>>> If not use DSA framework, normally we will use eth0.x and eth0.y for

>>>> wan

>>>> and lan.

>>>> On this case, customer usually also assign the MAC address on these

>>>> logical interface

>>>> from it's pool.

>>>

>>> OK, but this is not necessary per my previous explanation: the CPU <=>

>>> WAN pipe is a separate broadcast domain (otherwise it is a security hole

>>> since you exposing LAN machines to the outside world), and so there is

>>> no need for a separate MAC address. It might be convenient to have one,

>>> especially for the provider, if they run a management software (e.g.:

>>> TR69), but it is not required per-se.

>>>

>>> Let me ask a secondary question here, how many Ethernet MACs connect to

>>> the switch in this configuration? Is there one that is supposed to be

>>> assigned all LAN traffic and one that is supposed to be assigned all WAN

>>> traffic? If so, then what you are doing makes even less

>>>

>>

>> Only one MAC connected to switch cpu port, both lan0 and wan0 are on

>> the top of

>> same interface(eth0).

>>

> Customer doesn't care about the MAC controller's MAC address, just leave

> it as the driver

> randomly generated. They just want to assign the MAC address on wan and

> lan DSA logical

> interface.

> 

> Many customer doesn't use DSA, for example, they use eth0.1/eth0.2 for

> lan/wan with one MAC controller.

> They configure switch wan port in vlan2 group, and lan port in vlan1

> group, they usually assign mac address

> on the logical interface(eth0.1&eth0.2), i think this is similar with

> DSA slave interfaces.


Yes it is a similar use case, and in both cases there is no really a
functional need for a separate MAC address for lan/eth0.1 or wan/eth0.2
since the switch should be configured to perform IVL (Individual VLAN
Learning) and would determine the egress port just fine based on the MAC
DA. Because it is an established practice does not mean we should not
challenge it :).

My issue with your change is that because DSA is meant to be a flexible
framework we do not know the type/nature of DSA master network device
that is going to be used. That DSA master network device may or may not
have it own MAC DA filtering capability. Having to filter its own MAC
address is fine and a well established behavior, having to filter for
more than one unicast address starts to be questionable and eats up
filter space that could be better used for filtering MC addresses
instead. Another possible concern is a station trying to spoof the MAC
address, some switches may support protecting only one UC/management MAC
address, so having more than one could create security attack surfaces.

To give you an example, I work with 3 generations of DSA master network
controllers (bcmgenet and bcmsysport drivers).

- GENET supports 17 perfect filters, but we must include its own MAC
address, the broadcast address and that leaves only 15 filters for MC

- SYSTEMPORT is always attached to a switch but supports filtering the
MAC DA based on its own MAC and then it is in promiscuous mode

So with your scheme, we would leave only 13 filters for MC on GENET and
we would putting the interface in promiscuous mode for SYSTEMPORT.

Until we have a better switch-side filtering framework (and this is
being worked on right now), I would prefer that we defer accepting those
type of features. Andrew and Vivien might feel differently about that
though.
-- 
Florian

Patch

diff --git a/include/net/dsa.h b/include/net/dsa.h
index b3eefe8e18fd..aa24ce756679 100644
--- a/include/net/dsa.h
+++ b/include/net/dsa.h
@@ -198,6 +198,7 @@  struct dsa_port {
 	unsigned int		index;
 	const char		*name;
 	const struct dsa_port	*cpu_dp;
+	const char		*mac;
 	struct device_node	*dn;
 	unsigned int		ageing_time;
 	u8			stp_state;
diff --git a/net/dsa/dsa2.c b/net/dsa/dsa2.c
index a1917025e155..afb7d9fa42f6 100644
--- a/net/dsa/dsa2.c
+++ b/net/dsa/dsa2.c
@@ -261,6 +261,7 @@  static int dsa_port_setup(struct dsa_port *dp)
 	int err = 0;
 
 	memset(&dp->devlink_port, 0, sizeof(dp->devlink_port));
+	dp->mac = of_get_mac_address(dp->dn);
 
 	if (dp->type != DSA_PORT_TYPE_UNUSED)
 		err = devlink_port_register(ds->devlink, &dp->devlink_port,
diff --git a/net/dsa/slave.c b/net/dsa/slave.c
index a3fcc1d01615..8e64c4e947c6 100644
--- a/net/dsa/slave.c
+++ b/net/dsa/slave.c
@@ -1308,7 +1308,10 @@  int dsa_slave_create(struct dsa_port *port)
 	slave_dev->features = master->vlan_features | NETIF_F_HW_TC;
 	slave_dev->hw_features |= NETIF_F_HW_TC;
 	slave_dev->ethtool_ops = &dsa_slave_ethtool_ops;
-	eth_hw_addr_inherit(slave_dev, master);
+	if (port->mac && is_valid_ether_addr(port->mac))
+		ether_addr_copy(slave_dev->dev_addr, port->mac);
+	else
+		eth_hw_addr_inherit(slave_dev, master);
 	slave_dev->priv_flags |= IFF_NO_QUEUE;
 	slave_dev->netdev_ops = &dsa_slave_netdev_ops;
 	slave_dev->switchdev_ops = &dsa_slave_switchdev_ops;