plugins: add plugins from containernetworking/cni

Plugins prepared from the containernetworking/cni repo as follows:

1) git reset --hard 1a9288c3c0
2) git remove everything not in plugins/
3) git remove plugins/test
4) git merge into containernetworking/plugins repo
5) adjust import paths for containernetworking/cni -> containernetworking/plugins

plugins/ipam/host-local/main.go

@@ -0,0 +1,86 @@
+// Copyright 2015 CNI authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package main
+
+import (
+	"github.com/containernetworking/plugins/plugins/ipam/host-local/backend/allocator"
+	"github.com/containernetworking/plugins/plugins/ipam/host-local/backend/disk"
+
+	"github.com/containernetworking/cni/pkg/skel"
+	"github.com/containernetworking/cni/pkg/types"
+	"github.com/containernetworking/cni/pkg/types/current"
+	"github.com/containernetworking/cni/pkg/version"
+)
+
+func main() {
+	skel.PluginMain(cmdAdd, cmdDel, version.All)
+}
+
+func cmdAdd(args *skel.CmdArgs) error {
+	ipamConf, confVersion, err := allocator.LoadIPAMConfig(args.StdinData, args.Args)
+	if err != nil {
+		return err
+	}
+
+	result := &current.Result{}
+
+	if ipamConf.ResolvConf != "" {
+		dns, err := parseResolvConf(ipamConf.ResolvConf)
+		if err != nil {
+			return err
+		}
+		result.DNS = *dns
+	}
+
+	store, err := disk.New(ipamConf.Name, ipamConf.DataDir)
+	if err != nil {
+		return err
+	}
+	defer store.Close()
+
+	allocator, err := allocator.NewIPAllocator(ipamConf, store)
+	if err != nil {
+		return err
+	}
+
+	ipConf, routes, err := allocator.Get(args.ContainerID)
+	if err != nil {
+		return err
+	}
+	result.IPs = []*current.IPConfig{ipConf}
+	result.Routes = routes
+
+	return types.PrintResult(result, confVersion)
+}
+
+func cmdDel(args *skel.CmdArgs) error {
+	ipamConf, _, err := allocator.LoadIPAMConfig(args.StdinData, args.Args)
+	if err != nil {
+		return err
+	}
+
+	store, err := disk.New(ipamConf.Name, ipamConf.DataDir)
+	if err != nil {
+		return err
+	}
+	defer store.Close()
+
+	ipAllocator, err := allocator.NewIPAllocator(ipamConf, store)
+	if err != nil {
+		return err
+	}
+
+	return ipAllocator.Release(args.ContainerID)
+}