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Message-ID: <da6bbb3b-344c-f032-fe03-5e8c8ac3c388@blackwall.org>
Date: Sun, 15 May 2022 09:32:01 +0300
From: Nikolay Aleksandrov <razor@...ckwall.org>
To: Jonathan Toppins <jtoppins@...hat.com>, netdev@...r.kernel.org
Cc: toke@...hat.com, Long Xin <lxin@...hat.com>,
"David S. Miller" <davem@...emloft.net>,
Eric Dumazet <edumazet@...gle.com>,
Jakub Kicinski <kuba@...nel.org>,
Paolo Abeni <pabeni@...hat.com>,
Jonathan Corbet <corbet@....net>,
Jay Vosburgh <j.vosburgh@...il.com>,
Veaceslav Falico <vfalico@...il.com>,
Andy Gospodarek <andy@...yhouse.net>,
linux-doc@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH net-next v3] bond: add mac filter option for balance-xor
On 15/05/2022 00:41, Nikolay Aleksandrov wrote:
> On 13/05/2022 20:43, Jonathan Toppins wrote:
>> Implement a MAC filter that prevents duplicate frame delivery when
>> handling BUM traffic. This attempts to partially replicate OvS SLB
>> Bonding[1] like functionality without requiring significant change
>> in the Linux bridging code.
>>
>> A typical network setup for this feature would be:
>>
>> .--------------------------------------------.
>> | .--------------------. |
>> | | | |
>> .-------------------. | |
>> | | Bond 0 | | | |
>> | .--'---. .---'--. | | |
>> .----|-| eth0 |-| eth1 |-|----. .-----+----. .----+------.
>> | | '------' '------' | | | Switch 1 | | Switch 2 |
>> | '---,---------------' | | +---+ |
>> | / | '----+-----' '----+------'
>> | .---'---. .------. | | |
>> | | br0 |----| VM 1 | | ~~~~~~~~~~~~~~~~~~~~~
>> | '-------' '------' | ( )
>> | | .------. | ( Rest of Network )
>> | '--------| VM # | | (_____________________)
>> | '------' |
>> | Host 1 |
>> '-----------------------------'
>>
>> Where 'VM1' and 'VM#' are hosts connected to a Linux bridge, br0, with
>> bond0 and its associated links, eth0 & eth1, provide ingress/egress. One
>> can assume bond0, br1, and hosts VM1 to VM# are all contained in a
>> single box, as depicted. Interfaces eth0 and eth1 provide redundant
>> connections to the data center with the requirement to use all bandwidth
>> when the system is functioning normally. Switch 1 and Switch 2 are
>> physical switches that do not implement any advanced L2 management
>> features such as MLAG, Cisco's VPC, or LACP.
>>
>> Combining this feature with vlan+srcmac hash policy allows a user to
>> create an access network without the need to use expensive switches that
>> support features like Cisco's VCP.
>>
>> [1] https://docs.openvswitch.org/en/latest/topics/bonding/#slb-bonding
>>
>> Co-developed-by: Long Xin <lxin@...hat.com>
>> Signed-off-by: Long Xin <lxin@...hat.com>
>> Signed-off-by: Jonathan Toppins <jtoppins@...hat.com>
>> ---
>>
>> Notes:
>> v2:
>> * dropped needless abstraction functions and put code in module init
>> * renamed variable "rc" to "ret" to stay consistent with most of the
>> code
>> * fixed parameter setting management, when arp-monitor is turned on
>> this feature will be turned off similar to how miimon and arp-monitor
>> interact
>> * renamed bond_xor_recv to bond_mac_filter_recv for a little more
>> clarity
>> * it appears the implied default return code for any bonding recv probe
>> must be `RX_HANDLER_ANOTHER`. Changed the default return code of
>> bond_mac_filter_recv to use this return value to not break skb
>> processing when the skb dev is switched to the bond dev:
>> `skb->dev = bond->dev`
>>
>> v3: Nik's comments
>> * clarified documentation
>> * fixed inline and basic reverse Christmas tree formatting
>> * zero'ed entry in mac_create
>> * removed read_lock taking in bond_mac_filter_recv
>> * made has_expired() atomic and removed critical sections
>> surrounding calls to has_expired(), this also removed the
>> use-after-free that would have occurred:
>> spin_lock_irqsave(&entry->lock, flags);
>> if (has_expired(bond, entry))
>> mac_delete(bond, entry);
>> spin_unlock_irqrestore(&entry->lock, flags); <---
>> * moved init/destroy of mac_filter_tbl to bond_open/bond_close
>> this removed the complex option dependencies, the only behavioural
>> change the user will see is if the bond is up and mac_filter is
>> enabled if they try and set arp_interval they will receive -EBUSY
>> * in bond_changelink moved processing of mac_filter option just below
>> mode processing
>>
>> Documentation/networking/bonding.rst | 20 +++
>> drivers/net/bonding/Makefile | 2 +-
>> drivers/net/bonding/bond_mac_filter.c | 201 ++++++++++++++++++++++++++
>> drivers/net/bonding/bond_mac_filter.h | 37 +++++
>> drivers/net/bonding/bond_main.c | 30 ++++
>> drivers/net/bonding/bond_netlink.c | 13 ++
>> drivers/net/bonding/bond_options.c | 81 +++++++++--
>> drivers/net/bonding/bonding_priv.h | 1 +
>> include/net/bond_options.h | 1 +
>> include/net/bonding.h | 3 +
>> include/uapi/linux/if_link.h | 1 +
>> 11 files changed, 373 insertions(+), 17 deletions(-)
>> create mode 100644 drivers/net/bonding/bond_mac_filter.c
>> create mode 100644 drivers/net/bonding/bond_mac_filter.h
>>
>
[snip]
The same problem solved using a few nftables rules (in case you don't want to load eBPF):
$ nft 'add table netdev nt'
$ nft 'add chain netdev nt bond0EgressFilter { type filter hook egress device bond0 priority 0; }'
$ nft 'add chain netdev nt bond0IngressFilter { type filter hook ingress device bond0 priority 0; }'
$ nft 'add set netdev nt macset { type ether_addr; flags timeout; }'
$ nft 'add rule netdev nt bond0EgressFilter set update ether saddr timeout 5s @macset'
$ nft 'add rule netdev nt bond0IngressFilter ether saddr @macset counter drop'
Cheers,
Nik
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