This changes the userspace proxy so that it cleans up its conntrack
settings when a service is removed (as the iptables proxy already
does). This could theoretically cause problems when a UDP service
as deleted and recreated quickly (with the same IP address). As
long as packets from the same UDP source IP and port were going to
the same destination IP and port, the the conntrack would apply and
the packets would be sent to the old destination.
This is astronomically unlikely if you did not specify the IP address
to use in the service, and even then, only happens with an "established"
UDP connection. However, in cases where a service could be "switched"
between using the iptables proxy and the userspace proxy, this case
becomes much more frequent.
This commit makes the userspace proxy keep an ObjectReference to the
service being proxied. This allows the consumers of the `ServiceInfo`
struct, like `ProxySockets` to emit events about or otherwise refer to
the service.
This commit adds a new method for constructing userspace proxiers,
`NewCustomProxier`. `NewCustomProxier` functions identically to
`NewProxier`, except that it allows a custom constructor method to
be passed in to construct instances of ProxySocket.
This commit makes it possible for the `ProxySocket` interface to be
implemented by types outside of the `userspace` package. It mainly just
exposes relevant types and fields as public.
Refactor `pkg/proxy/config`’s ServiceConfigHandler.OnUpdate and
EndpointsConfigHandler.OnUpdate to different method names as they have
different signatures.
This will let the new proxy
(https://github.com/GoogleCloudPlatform/kubernetes/issues/3760)
implement both interfaces.
Since we won’t need a separate loadbalancer structure (load balancing
is handled in the proxy rules), we will simply handle both event types
from the same object.
Moves the userspace code in proxy to a sub-package and adds the
ProxyProvider interface.
This is in preparation for landing an implementation of
https://github.com/GoogleCloudPlatform/kubernetes/issues/3760, which
will mostly be in another sub package for iptables.
