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Message-ID: <53357187-aedf-20dd-a331-bc501aa0484e@blackwall.org>
Date: Mon, 16 May 2022 20:22:40 +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 16/05/2022 17:06, Jonathan Toppins wrote:
> On 5/15/22 02:32, Nikolay Aleksandrov wrote:
>> 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'
>>
>
> I get the following when trying to apply this on a fedora 35 install.
>
> root@...ora ~]# ip link add bond0 type bond mode balance-xor xmit_hash_policy vlan+srcmac
> [root@...ora ~]# nft 'add table netdev nt'
> [root@...ora ~]# nft 'add chain netdev nt bond0EgressFilter { type filter hook egress device bond0 priority 0; }'
> Error: unknown chain hook
> add chain netdev nt bond0EgressFilter { type filter hook egress device bond0 priority 0; }
> ^^^^^^
> [root@...ora ~]# uname -a
> Linux fedora 5.17.5-200.fc35.x86_64 #1 SMP PREEMPT Thu Apr 28 15:41:41 UTC 2022 x86_64 x86_64 x86_64 GNU/Linux
>
Well, take it up with the Fedora nftables package maintainer. :)
Your nftables version is old (I'd guess <1.0.1):
commit 510c4fad7e78
Author: Lukas Wunner <lukas@...ner.de>
Date: Wed Mar 11 13:20:06 2020 +0100
src: Support netdev egress hook
$ git tag --contains 510c4fad7e78f
v1.0.1
v1.0.2
I just tested it[1] on Linux 5.16.18-200.fc35.x86_64 #1 SMP PREEMPT Mon Mar 28 14:10:07 UTC 2022 x86_64 x86_64 x86_64 GNU/Linux
Cheers,
Nik
[1] You can clearly see the dynamically learned mac on egress (52:54:00:23:5f:13) and traffic
with that source is now blocked on ingress.
$ nft -a list table netdev nt
set macset { # handle 10
type ether_addr
size 65535
flags timeout
elements = { 52:54:00:23:5f:13 timeout 5s expires 4s192ms }
}
chain bond0EgressFilter { # handle 8
type filter hook egress device "bond0" priority filter; policy accept;
update @macset { ether saddr timeout 5s } # handle 11
}
chain bond0IngressFilter { # handle 9
type filter hook ingress device "bond0" priority filter; policy accept;
}
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