Faucet

* Fix modifying meter options now safe when running multiple redundant faucet controllers
* Fix race condition between reading a config file, and calculating its hash
* Add spine and leaf generative unit tests
* Fix mailing list URLs in README
* Add Prometheus metric to track changes to stack state, lacp status and stack root
* Enable unit testing of faucet on python3.9
* Reimplement faucet release process to protect credential handling on GitHub Actions
* Use system pip for most of our install mechanisms to avoid causing incompatibilities by installing a version that is too new
* Update docker base image used for faucet tests
* Change to Debian Buster from Ubuntu Bionic as Ubuntu has stopped supporting i386.
* Upgrade openvswitch to v2.15.0.
* Upgrade mininet to v2.3.0.
* Update dependencies:
* Upgrade grafana to v7.5.7 [apt, docker]
* Upgrade prometheus to v2.27.1 [docker]
* Upgrade influxdb to 2.0 [docker]
* Upgrade pytype to 2021.5.19 [tests]
* Upgrade pylint to 2.8.2 [tests]
* Upgrade scapy to 2.4.5 [tests]
* Upgrade exabgp to 4.2.13 [tests]
* Upgrade pika to 1.2.0 [rabbitmq adapter]
* Upgrade sphinx to 4.0.2 [docs]
* Upgrade sphinx_rtd_theme to 0.5.2 [docs]

* Implement bidirectional tunnels across a stack for supporting centralized NFV services
* Fix tunnel ACL on a port not handled
* Fix rabbitmq adapter docker image build
* Fix controller redundancy for groupmod
* Fix dp_root_hop_port not set after cold start
* Fix packaging unit tests (broken by internal pip API change)
* Update dependencies:
* Upgrade grafana to v7.3.4 [apt, docker]
* Upgrade prometheus to v2.23.0 [docker]
* Upgrade pytype to v2020.12.2 [tests]

* Reduce forwarding impact of warm starts
* Avoid sending deletes that overlap with adds
* Fix cold starting a switch already in restart resulting in stale flows
* Refine choice of redundant stack root when stack is degraded
* Ignore disconnected switches
* When deciding between candidate stack roots with equal numbers of down ports, use LACP ports in nosync state as tie break
* Don't provision meters if they are not used by any ACL
* Do not run pytype CI job on python3.5 (pytype no longer supports python3.5)
* Update dependencies:
* Upgrade prometheus_client to v0.9.0 [apt, pip]
* Upgrade grafana to v7.3.3 [apt, docker]
* Upgrade prometheus to v2.22.2 [docker]
* Upgrade sphinx to v3.3.1 [docs]
* Upgrade pytype to v2020.11.12 [tests]

* Update Cisco documentation to include configuration for a larger TCP window so that OpenFlow connections are more stable when large numbers of flow modifications are sent.
* No longer use wildcard VLAN delete - makes adding/removing ports to a VLAN less computationally expensive.
* Clone dynamic stack state on stack root change to make change over smoother.
* Fix transient build error with rabbitmq adapter docker image.
* Fix build error with faucetagent docker image.
* Add 32bit support for running the test suite.
* Fix unnecessary apt package installation during test suite run.
* Update dependencies:
* Upgrade prometheus to v2.22.0 [docker]
* Upgrade grafana to v7.2.2 [apt, docker]
* Upgrade pytype to v2020.10.8 [tests]
* Upgrade faucet/test-base Docker tag to v8.0.4 [tests]

* Fix crash handling flooded packet when initializing routing + stacking
* Fix initially hardcoded stack flood ports assumption
* Fix running of FaucetUntaggedNoCombinatorialFloodTest and FaucetMultiDPTest integration tests
* Flush L2 learning Prometheus variables on config reload
* Reduce impact of enabling mirroring on a VLAN, when mirroring a port
* Reduce CPU usage parsing config files
* Allow ACLs to output packets to the input port by manually outputting to OFP_IN_PORT
* Add integration tests for DHCP
* Allow DPs without any VLANs
* Add integration test coverage for multiple controllers
* Refactor Github Action CI workflows
* Update dependencies:
* Upgrade prometheus to v2.21.0 [docker]
* Upgrade grafana to v7.2.0 [apt, docker]
* Upgrade sphinx to v3.2.1 [docs]
* Upgrade pytype to v2020.9.29 [tests]
* Upgrade scapy to v2.4.4 [tests]
* Upgrade pylint to v2.6.0 [tests]

* Significant refactoring of stacking implementation for easier maintenance
* Better diagnostics for CI test framework
* Ensure entire CI test framework is run when code is merged
* Use github actions to build python packages on release
* Add unit tests for redundant controllers sending flowmods offset in time.
* Set LLDP interval to max of fast advertise interval and send interval
* Fix implicitly created VLAN conflicting with explicitly created VLAN with same VID
* Fix tunnels having multiple sources across different DPs
* Fix tunnel destination cannot be a stack port
* Fix tunnel not applied on warm start if stack topology did not change
* Update dependencies:
* Upgrade exabgp 4.2.11 [tests]
* Upgrade pytype to 2020.8.10 [tests]
* Upgrade sphinx to 3.2.0 [docs]
* Upgrade grafana to 7.1.4 [apt, docker]
* Upgrade prometheus to 2.20.1 [docker]