Port networking to CNI

Replaced netns utility with CNI plugins to create a bridge network
and allow communication between containers with firewall plugin.

Overwrite the CNI config in case it exists. Allow updating the config
on new versions.

Signed-off-by: Carlos de Paula <me@carlosedp.com>

vendor/github.com/containernetworking/cni/pkg/version/version.go

@@ -0,0 +1,83 @@
+// Copyright 2016 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 version
+
+import (
+	"encoding/json"
+	"fmt"
+
+	"github.com/containernetworking/cni/pkg/types"
+	"github.com/containernetworking/cni/pkg/types/020"
+	"github.com/containernetworking/cni/pkg/types/current"
+)
+
+// Current reports the version of the CNI spec implemented by this library
+func Current() string {
+	return "0.4.0"
+}
+
+// Legacy PluginInfo describes a plugin that is backwards compatible with the
+// CNI spec version 0.1.0.  In particular, a runtime compiled against the 0.1.0
+// library ought to work correctly with a plugin that reports support for
+// Legacy versions.
+//
+// Any future CNI spec versions which meet this definition should be added to
+// this list.
+var Legacy = PluginSupports("0.1.0", "0.2.0")
+var All = PluginSupports("0.1.0", "0.2.0", "0.3.0", "0.3.1", "0.4.0")
+
+var resultFactories = []struct {
+	supportedVersions []string
+	newResult         types.ResultFactoryFunc
+}{
+	{current.SupportedVersions, current.NewResult},
+	{types020.SupportedVersions, types020.NewResult},
+}
+
+// Finds a Result object matching the requested version (if any) and asks
+// that object to parse the plugin result, returning an error if parsing failed.
+func NewResult(version string, resultBytes []byte) (types.Result, error) {
+	reconciler := &Reconciler{}
+	for _, resultFactory := range resultFactories {
+		err := reconciler.CheckRaw(version, resultFactory.supportedVersions)
+		if err == nil {
+			// Result supports this version
+			return resultFactory.newResult(resultBytes)
+		}
+	}
+
+	return nil, fmt.Errorf("unsupported CNI result version %q", version)
+}
+
+// ParsePrevResult parses a prevResult in a NetConf structure and sets
+// the NetConf's PrevResult member to the parsed Result object.
+func ParsePrevResult(conf *types.NetConf) error {
+	if conf.RawPrevResult == nil {
+		return nil
+	}
+
+	resultBytes, err := json.Marshal(conf.RawPrevResult)
+	if err != nil {
+		return fmt.Errorf("could not serialize prevResult: %v", err)
+	}
+
+	conf.RawPrevResult = nil
+	conf.PrevResult, err = NewResult(conf.CNIVersion, resultBytes)
+	if err != nil {
+		return fmt.Errorf("could not parse prevResult: %v", err)
+	}
+
+	return nil
+}