From: roopa <roopa@cumulusnetworks•com>
To: Scott Feldman <sfeldma@gmail•com>
Cc: "David S. Miller" <davem@davemloft•net>,
"Jiří Pírko" <jiri@resnulli•us>,
"Arad, Ronen" <ronen.arad@intel•com>,
Netdev <netdev@vger•kernel.org>
Subject: Re: [PATCH net-next RFC v2] switchdev: bridge: drop hardware forwarded packets
Date: Fri, 20 Mar 2015 14:20:54 -0700 [thread overview]
Message-ID: <550C8F36.9030800@cumulusnetworks.com> (raw)
In-Reply-To: <CAE4R7bCXTB0eZdyT9+a2FbJvy4K7QHpRzR4WvRGMryE-QZN8zQ@mail.gmail.com>
On 3/20/15, 11:03 AM, Scott Feldman wrote:
> On Fri, Mar 20, 2015 at 9:58 AM, <roopa@cumulusnetworks•com> wrote:
>> From: Roopa Prabhu <roopa@cumulusnetworks•com>
>>
>> On a Linux bridge with bridge forwarding offloaded to switch ASIC,
>> there is a need to not re-forward frames that have already been
>> forwarded in hardware.
>>
>> Typically these are broadcast or multicast frames forwarded by the
>> hardware to multiple destination ports including sending a copy of
>> the packet to the cpu (kernel e.g. an arp broadcast).
>> The bridge driver will try to forward the packet again, resulting in
>> two copies of the same packet.
>>
>> These packets can also come up to the kernel for logging when they hit
>> a LOG acl rule in hardware. In such cases, you do want the packet
>> to go through the bridge netfilter hooks. Hence, this patch adds the
>> required checks just before the packet is being xmited.
>>
>> v2:
>> - Add a new hw_fwded flag in skbuff to indicate that the packet
>> is already hardware forwarded. Switch driver will set this flag.
>> I have been trying to avoid having this flag in the skb
>> and thats why this patch has been in my tree for long. Cant think
>> of other better alternatives. Suggestions are welcome. I have put
>> this under CONFIG_NET_SWITCHDEV to minimize the impact.
>>
>> Signed-off-by: Roopa Prabhu <roopa@cumulusnetworks•com>
>> Signed-off-by: Wilson Kok <wkok@cumulusnetworks•com>
>> ---
>> include/linux/skbuff.h | 7 +++++--
>> net/bridge/br_forward.c | 11 +++++++++++
>> 2 files changed, 16 insertions(+), 2 deletions(-)
>>
>> diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
>> index bba1330..1973b5c 100644
>> --- a/include/linux/skbuff.h
>> +++ b/include/linux/skbuff.h
>> @@ -560,8 +560,11 @@ struct sk_buff {
>> fclone:2,
>> peeked:1,
>> head_frag:1,
>> - xmit_more:1;
>> - /* one bit hole */
>> + xmit_more:1,
>> +#ifdef CONFIG_NET_SWITCHDEV
>> + hw_fwded:1;
>> +#endif
>> + /* one bit hole if CONFIG_NET_SWITCHDEV not defined */
> Did you want this flag not copied in __copy_skb_header()? Seems those
> flags are special cased. There is room for a bit here:
>
> #ifdef CONFIG_IPV6_NDISC_NODETYPE
> __u8 ndisc_nodetype:2;
> #endif
> __u8 ipvs_property:1;
> __u8 inner_protocol_type:1;
> __u8 remcsum_offload:1;
> /* 3 or 5 bit hole */
> <<<<<<<<
thx, yes I can add it here.
(I found the first 1 bit hole and added it there).
>
>> kmemcheck_bitfield_end(flags1);
>>
>> /* fields enclosed in headers_start/headers_end are copied
>> diff --git a/net/bridge/br_forward.c b/net/bridge/br_forward.c
>> index 3304a54..b60b96e 100644
>> --- a/net/bridge/br_forward.c
>> +++ b/net/bridge/br_forward.c
>> @@ -37,6 +37,17 @@ static inline int should_deliver(const struct net_bridge_port *p,
>>
>> int br_dev_queue_push_xmit(struct sk_buff *skb)
>> {
>> +
>> +#ifdef CONFIG_NET_SWITCHDEV
>> + /* If skb is already hw forwarded and the port being forwarded
>> + * to is a switch port, dont reforward
>> + */
>> + if (skb->hw_fwded && (skb->dev->features & NETIF_F_HW_SWITCH_OFFLOAD)) {
> The check for skb->dev->features & NETIF_F_HW_SWITCH_OFFLOAD is redundant.
The skb->dev is the device it is getting forwarded to. The hw_fwded flag
was set by the
device that originated the skb. The NETIF_F_HW_SWITCH_OFFLOAD flag is
required because
the device being forwarded to can be a non switch port.
thanks,
Roopa
next prev parent reply other threads:[~2015-03-20 21:20 UTC|newest]
Thread overview: 51+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-03-20 16:58 [PATCH net-next RFC v2] switchdev: bridge: drop hardware forwarded packets roopa
2015-03-20 17:11 ` John Fastabend
2015-03-20 18:13 ` Scott Feldman
2015-03-20 18:30 ` John Fastabend
2015-03-20 22:06 ` roopa
2015-03-20 22:37 ` Scott Feldman
2015-03-20 23:30 ` roopa
2015-03-21 0:26 ` Scott Feldman
2015-03-21 5:53 ` roopa
2015-03-20 21:03 ` roopa
2015-03-20 21:23 ` John Fastabend
2015-03-20 22:04 ` Andrew Lunn
2015-03-20 23:12 ` roopa
2015-03-20 18:03 ` Scott Feldman
2015-03-20 21:20 ` roopa [this message]
2015-03-20 20:36 ` David Miller
2015-03-20 21:36 ` roopa
2015-03-20 22:09 ` Andrew Lunn
2015-03-20 23:43 ` Florian Fainelli
2015-03-23 0:22 ` Guenter Roeck
2015-03-23 1:33 ` John Fastabend
2015-03-23 2:57 ` Guenter Roeck
2015-03-23 3:18 ` John Fastabend
2015-03-23 3:33 ` Guenter Roeck
2015-03-23 17:12 ` roopa
2015-03-24 5:59 ` Scott Feldman
2015-03-24 13:13 ` Guenter Roeck
2015-03-24 18:08 ` Scott Feldman
2015-03-24 14:29 ` Jiri Pirko
2015-03-24 16:01 ` Guenter Roeck
2015-03-24 17:45 ` roopa
2015-03-24 17:58 ` Guenter Roeck
2015-03-24 18:14 ` Scott Feldman
2015-03-25 3:10 ` Guenter Roeck
2015-03-25 3:46 ` Florian Fainelli
2015-03-25 5:06 ` Scott Feldman
2015-03-25 17:01 ` roopa
2015-03-26 7:44 ` Scott Feldman
2015-03-26 8:20 ` Jiri Pirko
2015-03-26 14:28 ` Scott Feldman
2015-03-26 14:49 ` Jiri Pirko
2015-03-27 1:08 ` Simon Horman
2015-03-27 6:02 ` Jiri Pirko
2015-03-27 6:43 ` Scott Feldman
2015-03-27 7:01 ` Jiri Pirko
2015-03-27 23:19 ` Scott Feldman
2015-03-30 14:06 ` roopa
2015-03-24 18:48 ` David Christensen
2015-03-24 17:58 ` Scott Feldman
2015-03-23 17:10 ` roopa
2015-03-23 14:00 ` roopa
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