Create an nftables.Interface in nftables proxier

And update most of the comments to refer to "nftables" rather than
"iptables" (even though it doesn't actually do any nftables updating
at this point).

For now the proxy also internally creates a
utiliptablestesting.FakeIPTables to keep the existing sync code
compiling.

cmd/kube-proxy/app/server_others.go

@@ -299,9 +299,7 @@ func (s *ProxyServer) createProxier(config *proxyconfigapi.KubeProxyConfiguratio
 
 			// TODO this has side effects that should only happen when Run() is invoked.
 			proxier, err = nftables.NewDualStackProxier(
-				ipt,
 				utilsysctl.New(),
-				execer,
 				config.NFTables.SyncPeriod.Duration,
 				config.NFTables.MinSyncPeriod.Duration,
 				config.NFTables.MasqueradeAll,
@@ -325,9 +323,7 @@ func (s *ProxyServer) createProxier(config *proxyconfigapi.KubeProxyConfiguratio
 			// TODO this has side effects that should only happen when Run() is invoked.
 			proxier, err = nftables.NewProxier(
 				s.PrimaryIPFamily,
-				iptInterface,
 				utilsysctl.New(),
-				execer,
 				config.NFTables.SyncPeriod.Duration,
 				config.NFTables.MinSyncPeriod.Duration,
 				config.NFTables.MasqueradeAll,

go.mod

@@ -27,6 +27,7 @@ require (
 	github.com/coreos/go-systemd/v22 v22.5.0
 	github.com/cpuguy83/go-md2man/v2 v2.0.2
 	github.com/cyphar/filepath-securejoin v0.2.4
+	github.com/danwinship/knftables v0.0.13
 	github.com/distribution/reference v0.5.0
 	github.com/docker/go-units v0.5.0
 	github.com/emicklei/go-restful/v3 v3.11.0

go.sum

@@ -308,6 +308,8 @@ github.com/creack/pty v1.1.18 h1:n56/Zwd5o6whRC5PMGretI4IdRLlmBXYNjScPaBgsbY=
 github.com/creack/pty v1.1.18/go.mod h1:MOBLtS5ELjhRRrroQr9kyvTxUAFNvYEK993ew/Vr4O4=
 github.com/cyphar/filepath-securejoin v0.2.4 h1:Ugdm7cg7i6ZK6x3xDF1oEu1nfkyfH53EtKeQYTC3kyg=
 github.com/cyphar/filepath-securejoin v0.2.4/go.mod h1:aPGpWjXOXUn2NCNjFvBE6aRxGGx79pTxQpKOJNYHHl4=
+github.com/danwinship/knftables v0.0.13 h1:89Ieiia6MMfXWQF9dyaou1CwBU8h8sHa2Zo3OlY2o04=
+github.com/danwinship/knftables v0.0.13/go.mod h1:OzipaBQqkQAIbVnafTGyHgfFbjWTJecrA7/XNLNMO5E=
 github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
 github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=