netdev - Re: [PATCH net-next 4/6] net: bridge: fdb: add support for flush filtering based on ndm flags and state

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Date:   Mon, 11 Apr 2022 12:07:14 +0300
From:   Nikolay Aleksandrov <razor@...ckwall.org>
To:     Ido Schimmel <idosch@...sch.org>
Cc:     netdev@...r.kernel.org, roopa@...dia.com, kuba@...nel.org,
        davem@...emloft.net, bridge@...ts.linux-foundation.org
Subject: Re: [PATCH net-next 4/6] net: bridge: fdb: add support for flush
 filtering based on ndm flags and state

On 11/04/2022 11:47, Ido Schimmel wrote:
> On Sat, Apr 09, 2022 at 01:58:55PM +0300, Nikolay Aleksandrov wrote:
>> Add support for fdb flush filtering based on ndm flags and state. The
>> new attributes allow users to specify a mask and value which are mapped
>> to bridge-specific flags. NTF_USE is used to represent added_by_user
>> flag since it sets it on fdb add and we don't have a 1:1 mapping for it.
>>
>> Signed-off-by: Nikolay Aleksandrov <razor@...ckwall.org>
>> ---
>>  include/uapi/linux/if_bridge.h |  4 +++
>>  net/bridge/br_fdb.c            | 55 ++++++++++++++++++++++++++++++++++
>>  2 files changed, 59 insertions(+)
>>
>> diff --git a/include/uapi/linux/if_bridge.h b/include/uapi/linux/if_bridge.h
>> index 2f3799cf14b2..4638d7e39f2a 100644
>> --- a/include/uapi/linux/if_bridge.h
>> +++ b/include/uapi/linux/if_bridge.h
>> @@ -815,6 +815,10 @@ enum {
>>  /* embedded in BRIDGE_FLUSH_FDB */
>>  enum {
>>  	FDB_FLUSH_UNSPEC,
>> +	FDB_FLUSH_NDM_STATE,
>> +	FDB_FLUSH_NDM_STATE_MASK,
>> +	FDB_FLUSH_NDM_FLAGS,
>> +	FDB_FLUSH_NDM_FLAGS_MASK,
>>  	__FDB_FLUSH_MAX
>>  };
>>  #define FDB_FLUSH_MAX (__FDB_FLUSH_MAX - 1)
>> diff --git a/net/bridge/br_fdb.c b/net/bridge/br_fdb.c
>> index 62f694a739e1..340a2ace1d5e 100644
>> --- a/net/bridge/br_fdb.c
>> +++ b/net/bridge/br_fdb.c
>> @@ -594,8 +594,40 @@ void br_fdb_flush(struct net_bridge *br,
>>  	rcu_read_unlock();
>>  }
>>  
>> +static unsigned long __ndm_state_to_fdb_flags(u16 ndm_state)
>> +{
>> +	unsigned long flags = 0;
>> +
>> +	if (ndm_state & NUD_PERMANENT)
>> +		__set_bit(BR_FDB_LOCAL, &flags);
>> +	if (ndm_state & NUD_NOARP)
>> +		__set_bit(BR_FDB_STATIC, &flags);
>> +
>> +	return flags;
>> +}
>> +
>> +static unsigned long __ndm_flags_to_fdb_flags(u16 ndm_flags)
>> +{
>> +	unsigned long flags = 0;
>> +
>> +	if (ndm_flags & NTF_USE)
>> +		__set_bit(BR_FDB_ADDED_BY_USER, &flags);
>> +	if (ndm_flags & NTF_EXT_LEARNED)
>> +		__set_bit(BR_FDB_ADDED_BY_EXT_LEARN, &flags);
>> +	if (ndm_flags & NTF_OFFLOADED)
>> +		__set_bit(BR_FDB_OFFLOADED, &flags);
>> +	if (ndm_flags & NTF_STICKY)
>> +		__set_bit(BR_FDB_STICKY, &flags);
>> +
>> +	return flags;
>> +}
>> +
>>  static const struct nla_policy br_fdb_flush_policy[FDB_FLUSH_MAX + 1] = {
>>  	[FDB_FLUSH_UNSPEC]	= { .type = NLA_REJECT },
>> +	[FDB_FLUSH_NDM_STATE]	= { .type = NLA_U16 },
>> +	[FDB_FLUSH_NDM_FLAGS]	= { .type = NLA_U16 },
>> +	[FDB_FLUSH_NDM_STATE_MASK]	= { .type = NLA_U16 },
>> +	[FDB_FLUSH_NDM_FLAGS_MASK]	= { .type = NLA_U16 },
> 
> Might be better to use NLA_POLICY_MASK(NLA_U16, mask) and reject
> unsupported states / flags instead of just ignoring them?
> 

Yep, forgot about that one. Good point!