netdev - Re: [RFC PATCH] Add bridge ifindex to bridge fdb notify msgs

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Message-ID: <5384C5C6.2090606@cumulusnetworks.com>
Date:	Tue, 27 May 2014 10:05:10 -0700
From:	Roopa Prabhu <roopa@...ulusnetworks.com>
To:	Stephen Hemminger <stephen@...workplumber.org>
CC:	davem@...emloft.net, netdev@...r.kernel.org,
	wkok@...ulusnetworks.com,
	Shrijeet Mukherjee <shm@...ulusnetworks.com>
Subject: Re: [RFC PATCH] Add bridge ifindex to bridge fdb notify msgs

On 5/27/14, 9:37 AM, Stephen Hemminger wrote:
> On Mon, 26 May 2014 21:39:46 -0700
> roopa@...ulusnetworks.com wrote:
>
>> From: Roopa Prabhu <roopa@...ulusnetworks.com>
>>
>> This patch adds NDA_MASTER attribute to neighbour attributes enum for
>> bridge/master ifindex. And adds NDA_MASTER to bridge fdb notify msgs.
>>
>> Today bridge fdb notifications dont contain bridge information.
>> Userspace can derive it from the port information in the fdb
>> notification. However this is tricky in some scenarious.
>>
>> Example, bridge port delete notification comes before bridge fdb
>> delete notifications. And we have seen problems in userspace
>> when using libnl where, the bridge fdb delete notification handling code
>> does not understand which bridge this fdb entry is part of because
>> the bridge and port association has already been deleted.
>> And these notifications (port membership and fdb) are generated on
>> separate rtnl groups.
>>
>> Fixing the order of notifications could possibly solve the problem
>> for some cases (I can submit a separate patch for that).
>>
>> This patch chooses to add NDA_MASTER to bridge fdb notify msgs
>> because it not only solves the problem described above, but also helps
>> userspace avoid another lookup into link msgs to derive the master index.
>>
>> Signed-off-by: Roopa Prabhu <roopa@...ulusnetworks.com>
>> ---
>>   include/uapi/linux/neighbour.h |    1 +
>>   net/bridge/br_fdb.c            |    3 +++
>>   2 files changed, 4 insertions(+)
>>
>> diff --git a/include/uapi/linux/neighbour.h b/include/uapi/linux/neighbour.h
>> index d3ef583..4a1d7e9 100644
>> --- a/include/uapi/linux/neighbour.h
>> +++ b/include/uapi/linux/neighbour.h
>> @@ -24,6 +24,7 @@ enum {
>>   	NDA_PORT,
>>   	NDA_VNI,
>>   	NDA_IFINDEX,
>> +	NDA_MASTER,
>>   	__NDA_MAX
>>   };
>>   
>> diff --git a/net/bridge/br_fdb.c b/net/bridge/br_fdb.c
>> index 9203d5a..019bb93 100644
>> --- a/net/bridge/br_fdb.c
>> +++ b/net/bridge/br_fdb.c
>> @@ -565,6 +565,8 @@ static int fdb_fill_info(struct sk_buff *skb, const struct net_bridge *br,
>>   
>>   	if (nla_put(skb, NDA_LLADDR, ETH_ALEN, &fdb->addr))
>>   		goto nla_put_failure;
>> +	if (nla_put_u32(skb, NDA_MASTER, br->dev->ifindex))
>> +		goto nla_put_failure;
>>   	ci.ndm_used	 = jiffies_to_clock_t(now - fdb->used);
>>   	ci.ndm_confirmed = 0;
>>   	ci.ndm_updated	 = jiffies_to_clock_t(now - fdb->updated);
>> @@ -586,6 +588,7 @@ static inline size_t fdb_nlmsg_size(void)
>>   {
>>   	return NLMSG_ALIGN(sizeof(struct ndmsg))
>>   		+ nla_total_size(ETH_ALEN) /* NDA_LLADDR */
>> +		+ nla_total_size(sizeof(u32)) /* NDA_MASTER */
>>   		+ nla_total_size(sizeof(u16)) /* NDA_VLAN */
>>   		+ nla_total_size(sizeof(struct nda_cacheinfo));
>>   }
> I like the idea of this, but the new attribute needs to be part of the set
> as well as notify and display infrastructure.
>
ok thanks, i will resubmit with set and other changes.
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