Date:   Wed, 15 Jan 2020 17:37:00 +0800
From:   wenxu <wenxu@...oud.cn>
To:     Or Gerlitz <gerlitz.or@...il.com>
Cc:     Paul Blakey <paulb@...lanox.com>,
        Saeed Mahameed <saeedm@...lanox.com>,
        Linux Netdev List <netdev@...r.kernel.org>
Subject: Re: [PATCH net-next v2] net/mlx5e: Add mlx5e_flower_parse_meta
 support


On 1/15/2020 5:13 PM, Or Gerlitz wrote:
> On Tue, Jan 7, 2020 at 11:17 AM <wenxu@...oud.cn> wrote:
>> In the flowtables offload all the devices in the flowtables
>> share the same flow_block. An offload rule will be installed on
> "In the flowtables offload all the devices in the flowtables share the"
>
> I am not managing to follow on this sentence. What does "devices in
> the flowtables" mean?


All the devices are added in flowtables.

>
>> all the devices. This scenario is not correct.
> so this is a fix and should go to net, or maybe the code you are fixing
> was only introduced in net-next?

The fix netfilter patch "netfilter: flowtable: restrict flow dissector match on meta ingress device"

now plans to be introduced to nf-next.

http://patchwork.ozlabs.org/patch/1222292/

>
>> It is no problem if there are only two devices in the flowtable,
>> The rule with ingress and egress on the same device can be reject
> nit: rejected
>
>> by driver.
>> But more than two devices in the flowtable will install the wrong
>> rules on hardware.
>>
>> For example:
>> Three devices in a offload flowtables: dev_a, dev_b, dev_c
>>
>> A rule ingress from dev_a and egress to dev_b:
>> The rule will install on device dev_a.
>> The rule will try to install on dev_b but failed for ingress
>> and egress on the same device.
>> The rule will install on dev_c. This is not correct.
>>
>> The flowtables offload avoid this case through restricting the ingress dev
>> with FLOW_DISSECTOR_KEY_META as following patch.
>> http://patchwork.ozlabs.org/patch/1218109/
>>
>> So the mlx5e driver also should support the FLOW_DISSECTOR_KEY_META parse.
>>
>> Signed-off-by: wenxu <wenxu@...oud.cn>
>> ---
>> v2: remap the patch description
>>
>>  drivers/net/ethernet/mellanox/mlx5/core/en_tc.c | 39 +++++++++++++++++++++++++
>>  1 file changed, 39 insertions(+)
>>
>> diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_tc.c b/drivers/net/ethernet/mellanox/mlx5/core/en_tc.c
>> index 9b32a9c..33d1ce5 100644
>> --- a/drivers/net/ethernet/mellanox/mlx5/core/en_tc.c
>> +++ b/drivers/net/ethernet/mellanox/mlx5/core/en_tc.c
>> @@ -1805,6 +1805,40 @@ static void *get_match_headers_value(u32 flags,
>>                              outer_headers);
>>  }
>>
>> +static int mlx5e_flower_parse_meta(struct net_device *filter_dev,
>> +                                  struct flow_cls_offload *f)
>> +{
>> +       struct flow_rule *rule = flow_cls_offload_flow_rule(f);
>> +       struct netlink_ext_ack *extack = f->common.extack;
>> +       struct net_device *ingress_dev;
>> +       struct flow_match_meta match;
>> +
>> +       if (!flow_rule_match_key(rule, FLOW_DISSECTOR_KEY_META))
>> +               return 0;
>> +
>> +       flow_rule_match_meta(rule, &match);
>> +       if (match.mask->ingress_ifindex != 0xFFFFFFFF) {
>> +               NL_SET_ERR_MSG_MOD(extack, "Unsupported ingress ifindex mask");
>> +               return -EINVAL;
>> +       }
>> +
>> +       ingress_dev = __dev_get_by_index(dev_net(filter_dev),
>> +                                        match.key->ingress_ifindex);
>> +       if (!ingress_dev) {
>> +               NL_SET_ERR_MSG_MOD(extack,
>> +                                  "Can't find the ingress port to match on");
>> +               return -EINVAL;
>> +       }
>> +
>> +       if (ingress_dev != filter_dev) {
>> +               NL_SET_ERR_MSG_MOD(extack,
>> +                                  "Can't match on the ingress filter port");
>> +               return -EINVAL;
>> +       }
>> +
>> +       return 0;
>> +}
>> +
>>  static int __parse_cls_flower(struct mlx5e_priv *priv,
>>                               struct mlx5_flow_spec *spec,
>>                               struct flow_cls_offload *f,
>> @@ -1825,6 +1859,7 @@ static int __parse_cls_flower(struct mlx5e_priv *priv,
>>         u16 addr_type = 0;
>>         u8 ip_proto = 0;
>>         u8 *match_level;
>> +       int err;
>>
>>         match_level = outer_match_level;
>>
>> @@ -1868,6 +1903,10 @@ static int __parse_cls_flower(struct mlx5e_priv *priv,
>>                                                     spec);
>>         }
>>
>> +       err = mlx5e_flower_parse_meta(filter_dev, f);
>> +       if (err)
>> +               return err;
>> +
>>         if (flow_rule_match_key(rule, FLOW_DISSECTOR_KEY_BASIC)) {
>>                 struct flow_match_basic match;
>>
>> --
>> 1.8.3.1
>>

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