On 5/15/22 02:32, Nikolay Aleksandrov wrote:

On 15/05/2022 00:41, Nikolay Aleksandrov wrote:

quoted

On 13/05/2022 20:43, Jonathan Toppins wrote:

quoted

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 <redacted>
Signed-off-by: Long Xin <redacted>
Signed-off-by: Jonathan Toppins <redacted>
---

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@fedora ~]# ip link add bond0 type bond mode balance-xor 
xmit_hash_policy vlan+srcmac
[root@fedora ~]# nft 'add table netdev nt'
[root@fedora ~]# 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@fedora ~]# 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