Re: [PATCH RFC v1 net-next 00/12] bridge-fastpath and related improvements

[Eric Woudstra <ericwouds@gmail.com>]

On 10/14/24 8:35 AM, Nikolay Aleksandrov wrote:
> On 13/10/2024 21:54, Eric Woudstra wrote:
>> This patchset makes it possible to set up a (hardware offloaded) fastpath
>> for bridged interfaces.
>>
> 
> The subject and this sentence are misleading, you're talking about netfilter bridge
> fastpath offload, please mention it in both places. When you just say bridge fast
> path, I think of the software fast path.
> 

Hello Nikolay,

It would be no problem for me to change the subject and body, if you
think that is better.

The thing is, these patches actually make it possible to set up a fully
functional software fastpath between bridged interfaces. Only after the
software fastpath is set up and functional, it can be offloaded, which
happens to by my personal motivation to write this patch-set.

If the offload flag is set in the flowtable, the software fastpath will
be offloaded. But in this patch-set, there is nothing that changes
anything there, the existing code is used unchanged.

>> To set up the fastpath with offloading, add this extra flowtable:
>>
>> table bridge filter {
>>         flowtable fb {
>>                 hook ingress priority filter
>>                 devices = { lan0, lan1, lan2, lan3, lan4, wlan0, wlan1 }
>>                 flags offload
>>         }
>>         chain forward {
>>                 type filter hook forward priority filter; policy accept;
>> 		ct state established flow add @fb
>>         }
>> }
>>
>> Creating a separate fastpath for bridges.
>>
>>          forward fastpath bypass
>>  .----------------------------------------.
>> /                                          \
>> |                        IP - forwarding    |
>> |                       /                \  v
>> |                      /                  wan ...
>> |                     /
>> |                     |
>> |                     |
>> |                   brlan.1
>> |                     |
>> |    +-------------------------------+
>> |    |           vlan 1              |
>> |    |                               |
>> |    |     brlan (vlan-filtering)    |
>> |    +---------------+               |
>> |    |  DSA-SWITCH   |               |
>> |    |               |    vlan 1     |
>> |    |               |      to       |
>> |    |   vlan 1      |   untagged    |
>> |    +---------------+---------------+
>> .         /                   \
>>  ------>lan0                 wlan1
>>         .  ^                 ^
>>         .  |                 |
>>         .  \_________________/
>>         .  bridge fastpath bypass
>>         .
>>         ^
>>      vlan 1 tagged packets
>>
>> To have the ability to handle xmit direct with outgoing encaps in the
>> bridge fastpass bypass, we need to be able to handle them without going
>> through vlan/pppoe devices. So I've applied, amended and squashed wenxu's
>> patchset. This patch also makes it possible to egress from vlan-filtering
>> brlan to lan0 with vlan tagged packets, if the bridge master port is doing
>> the vlan tagging, instead of the vlan-device. Without this patch, this is
>> not possible in the bridge-fastpath and also not in the forward-fastpath,
>> as seen in the figure above.
>>
>> There are also some more fixes for filling in the forward path. These
>> fixes also apply to for the forward-fastpath. They include handling
>> DEV_PATH_MTK_WDMA in nft_dev_path_info() and avoiding
>> DEV_PATH_BR_VLAN_UNTAG_HW for bridges with ports that use dsa.
>>
>> Conntrack bridge only tracks untagged and 802.1q. To make the bridge
>> fastpath experience more similar to the forward fastpath experience,
>> I've added double vlan, pppoe and pppoe-in-q tagged packets to bridge
>> conntrack and to bridge filter chain.
>>
>> Eric Woudstra (12):
>>   netfilter: nf_flow_table_offload: Add nf_flow_encap_push() for xmit
>>     direct
>>   netfilter: bridge: Add conntrack double vlan and pppoe
>>   netfilter: nft_chain_filter: Add bridge double vlan and pppoe
>>   bridge: br_vlan_fill_forward_path_pvid: Add port to port
>>   bridge: br_fill_forward_path add port to port
>>   net: core: dev: Add dev_fill_bridge_path()
>>   netfilter :nf_flow_table_offload: Add nf_flow_rule_bridge()
>>   netfilter: nf_flow_table_inet: Add nf_flowtable_type flowtable_bridge
>>   netfilter: nft_flow_offload: Add NFPROTO_BRIDGE to validate
>>   netfilter: nft_flow_offload: Add DEV_PATH_MTK_WDMA to
>>     nft_dev_path_info()
>>   bridge: br_vlan_fill_forward_path_mode no _UNTAG_HW for dsa
>>   netfilter: nft_flow_offload: Add bridgeflow to nft_flow_offload_eval()
>>
>>  include/linux/netdevice.h                  |   2 +
>>  include/net/netfilter/nf_flow_table.h      |   3 +
>>  net/bridge/br_device.c                     |  20 ++-
>>  net/bridge/br_private.h                    |   2 +
>>  net/bridge/br_vlan.c                       |  24 +++-
>>  net/bridge/netfilter/nf_conntrack_bridge.c |  86 ++++++++++--
>>  net/core/dev.c                             |  77 +++++++++--
>>  net/netfilter/nf_flow_table_inet.c         |  13 ++
>>  net/netfilter/nf_flow_table_ip.c           |  96 ++++++++++++-
>>  net/netfilter/nf_flow_table_offload.c      |  13 ++
>>  net/netfilter/nft_chain_filter.c           |  20 ++-
>>  net/netfilter/nft_flow_offload.c           | 154 +++++++++++++++++++--
>>  12 files changed, 463 insertions(+), 47 deletions(-)
>>
>