KVM: add configurable MAC/IP script hook for static ARP/NDP and routes

[wido]

Introduces a new agent.properties option vm.network.macip.static (false disabled by default) that makes BridgeVifDriver invoke modifymacip.sh on every NIC plug (VM start) and unplug (VM stop).

This will lead to static IPv4/IPv6 ARP/NDP entries to be programmed into the kernel.

This is very useful in EVPN+VXLAN environments as it can reduce BUM traffic. By setting static ARP/NDP entries bridges can be configured using 'neigh_suppress on' as the ARP/NDP entries are already set statically by CloudStack. No ARP/NDP traffic is needed in this case as it's handled locally.

When using EVPN+VXLAN you will need to change the modifyvxlan.sh script so that it does this:

bridge link show|grep ${VXLAN_BR}|awk '{print $2}'|grep "^${VXLAN_DEV}\$" > /dev/null
    if [[ $? -gt 0 ]]; then
        ip link set ${VXLAN_DEV} master ${VXLAN_BR}
        bridge link set dev ${VXLAN_DEV} neigh_suppress on
        bridge link set dev ${VXLAN_DEV} learning off
    fi

Further improvements can be made in general to the VXLAN+EVPN integration, but this should already resolve many problems people might have with BUM traffic.

[codecov]

Codecov Report

❌ Patch coverage is 10.00000% with 45 lines in your changes missing coverage. Please review.
✅ Project coverage is 18.93%. Comparing base (d2c8aa7) to head (642f086).
⚠️ Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
...cloud/hypervisor/kvm/resource/BridgeVifDriver.java	8.16%	43 Missing and 2 partials ⚠️

Additional details and impacted files

@@            Coverage Diff            @@
##               main   #13495   +/-   ##
=========================================
  Coverage     18.93%   18.93%           
- Complexity    18471    18475    +4     
=========================================
  Files          6221     6221           
  Lines        560045   560095   +50     
  Branches      68289    68298    +9     
=========================================
+ Hits         106048   106074   +26     
- Misses       442372   442392   +20     
- Partials      11625    11629    +4     

Flag	Coverage Δ
uitests	3.50% <ø> (ø)
unittests	20.14% <10.00%> (+<0.01%)	⬆️

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[DaanHoogland]

clgtm, why not set your script as default value for the property @wido ? (if it is well tested and robust, that is)

[wido]

clgtm, why not set your script as default value for the property @wido ? (if it is well tested and robust, that is)

Thanks, the reason the script does not always execute is that it could break existing setups. Therefor it is not set by default.

[DaanHoogland]

clgtm, why not set your script as default value for the property @wido ? (if it is well tested and robust, that is)

Thanks, the reason the script does not always execute is that it could break existing setups. Therefor it is not set by default.

yeah, that is what I meant by robust ;) np, fine like this as well.

[wido]

I tested and reviewed the code again. It worked on our environment, would be great to get feedback. This can be merged without changing anything to existing setups as you will need to enable it manually.