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/libcni/conf.go

@@ -0,0 +1,268 @@
+// 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 libcni
+
+import (
+	"encoding/json"
+	"fmt"
+	"io/ioutil"
+	"os"
+	"path/filepath"
+	"sort"
+)
+
+type NotFoundError struct {
+	Dir  string
+	Name string
+}
+
+func (e NotFoundError) Error() string {
+	return fmt.Sprintf(`no net configuration with name "%s" in %s`, e.Name, e.Dir)
+}
+
+type NoConfigsFoundError struct {
+	Dir string
+}
+
+func (e NoConfigsFoundError) Error() string {
+	return fmt.Sprintf(`no net configurations found in %s`, e.Dir)
+}
+
+func ConfFromBytes(bytes []byte) (*NetworkConfig, error) {
+	conf := &NetworkConfig{Bytes: bytes}
+	if err := json.Unmarshal(bytes, &conf.Network); err != nil {
+		return nil, fmt.Errorf("error parsing configuration: %s", err)
+	}
+	if conf.Network.Type == "" {
+		return nil, fmt.Errorf("error parsing configuration: missing 'type'")
+	}
+	return conf, nil
+}
+
+func ConfFromFile(filename string) (*NetworkConfig, error) {
+	bytes, err := ioutil.ReadFile(filename)
+	if err != nil {
+		return nil, fmt.Errorf("error reading %s: %s", filename, err)
+	}
+	return ConfFromBytes(bytes)
+}
+
+func ConfListFromBytes(bytes []byte) (*NetworkConfigList, error) {
+	rawList := make(map[string]interface{})
+	if err := json.Unmarshal(bytes, &rawList); err != nil {
+		return nil, fmt.Errorf("error parsing configuration list: %s", err)
+	}
+
+	rawName, ok := rawList["name"]
+	if !ok {
+		return nil, fmt.Errorf("error parsing configuration list: no name")
+	}
+	name, ok := rawName.(string)
+	if !ok {
+		return nil, fmt.Errorf("error parsing configuration list: invalid name type %T", rawName)
+	}
+
+	var cniVersion string
+	rawVersion, ok := rawList["cniVersion"]
+	if ok {
+		cniVersion, ok = rawVersion.(string)
+		if !ok {
+			return nil, fmt.Errorf("error parsing configuration list: invalid cniVersion type %T", rawVersion)
+		}
+	}
+
+	disableCheck := false
+	if rawDisableCheck, ok := rawList["disableCheck"]; ok {
+		disableCheck, ok = rawDisableCheck.(bool)
+		if !ok {
+			return nil, fmt.Errorf("error parsing configuration list: invalid disableCheck type %T", rawDisableCheck)
+		}
+	}
+
+	list := &NetworkConfigList{
+		Name:         name,
+		DisableCheck: disableCheck,
+		CNIVersion:   cniVersion,
+		Bytes:        bytes,
+	}
+
+	var plugins []interface{}
+	plug, ok := rawList["plugins"]
+	if !ok {
+		return nil, fmt.Errorf("error parsing configuration list: no 'plugins' key")
+	}
+	plugins, ok = plug.([]interface{})
+	if !ok {
+		return nil, fmt.Errorf("error parsing configuration list: invalid 'plugins' type %T", plug)
+	}
+	if len(plugins) == 0 {
+		return nil, fmt.Errorf("error parsing configuration list: no plugins in list")
+	}
+
+	for i, conf := range plugins {
+		newBytes, err := json.Marshal(conf)
+		if err != nil {
+			return nil, fmt.Errorf("Failed to marshal plugin config %d: %v", i, err)
+		}
+		netConf, err := ConfFromBytes(newBytes)
+		if err != nil {
+			return nil, fmt.Errorf("Failed to parse plugin config %d: %v", i, err)
+		}
+		list.Plugins = append(list.Plugins, netConf)
+	}
+
+	return list, nil
+}
+
+func ConfListFromFile(filename string) (*NetworkConfigList, error) {
+	bytes, err := ioutil.ReadFile(filename)
+	if err != nil {
+		return nil, fmt.Errorf("error reading %s: %s", filename, err)
+	}
+	return ConfListFromBytes(bytes)
+}
+
+func ConfFiles(dir string, extensions []string) ([]string, error) {
+	// In part, adapted from rkt/networking/podenv.go#listFiles
+	files, err := ioutil.ReadDir(dir)
+	switch {
+	case err == nil: // break
+	case os.IsNotExist(err):
+		return nil, nil
+	default:
+		return nil, err
+	}
+
+	confFiles := []string{}
+	for _, f := range files {
+		if f.IsDir() {
+			continue
+		}
+		fileExt := filepath.Ext(f.Name())
+		for _, ext := range extensions {
+			if fileExt == ext {
+				confFiles = append(confFiles, filepath.Join(dir, f.Name()))
+			}
+		}
+	}
+	return confFiles, nil
+}
+
+func LoadConf(dir, name string) (*NetworkConfig, error) {
+	files, err := ConfFiles(dir, []string{".conf", ".json"})
+	switch {
+	case err != nil:
+		return nil, err
+	case len(files) == 0:
+		return nil, NoConfigsFoundError{Dir: dir}
+	}
+	sort.Strings(files)
+
+	for _, confFile := range files {
+		conf, err := ConfFromFile(confFile)
+		if err != nil {
+			return nil, err
+		}
+		if conf.Network.Name == name {
+			return conf, nil
+		}
+	}
+	return nil, NotFoundError{dir, name}
+}
+
+func LoadConfList(dir, name string) (*NetworkConfigList, error) {
+	files, err := ConfFiles(dir, []string{".conflist"})
+	if err != nil {
+		return nil, err
+	}
+	sort.Strings(files)
+
+	for _, confFile := range files {
+		conf, err := ConfListFromFile(confFile)
+		if err != nil {
+			return nil, err
+		}
+		if conf.Name == name {
+			return conf, nil
+		}
+	}
+
+	// Try and load a network configuration file (instead of list)
+	// from the same name, then upconvert.
+	singleConf, err := LoadConf(dir, name)
+	if err != nil {
+		// A little extra logic so the error makes sense
+		if _, ok := err.(NoConfigsFoundError); len(files) != 0 && ok {
+			// Config lists found but no config files found
+			return nil, NotFoundError{dir, name}
+		}
+
+		return nil, err
+	}
+	return ConfListFromConf(singleConf)
+}
+
+func InjectConf(original *NetworkConfig, newValues map[string]interface{}) (*NetworkConfig, error) {
+	config := make(map[string]interface{})
+	err := json.Unmarshal(original.Bytes, &config)
+	if err != nil {
+		return nil, fmt.Errorf("unmarshal existing network bytes: %s", err)
+	}
+
+	for key, value := range newValues {
+		if key == "" {
+			return nil, fmt.Errorf("keys cannot be empty")
+		}
+
+		if value == nil {
+			return nil, fmt.Errorf("key '%s' value must not be nil", key)
+		}
+
+		config[key] = value
+	}
+
+	newBytes, err := json.Marshal(config)
+	if err != nil {
+		return nil, err
+	}
+
+	return ConfFromBytes(newBytes)
+}
+
+// ConfListFromConf "upconverts" a network config in to a NetworkConfigList,
+// with the single network as the only entry in the list.
+func ConfListFromConf(original *NetworkConfig) (*NetworkConfigList, error) {
+	// Re-deserialize the config's json, then make a raw map configlist.
+	// This may seem a bit strange, but it's to make the Bytes fields
+	// actually make sense. Otherwise, the generated json is littered with
+	// golang default values.
+
+	rawConfig := make(map[string]interface{})
+	if err := json.Unmarshal(original.Bytes, &rawConfig); err != nil {
+		return nil, err
+	}
+
+	rawConfigList := map[string]interface{}{
+		"name":       original.Network.Name,
+		"cniVersion": original.Network.CNIVersion,
+		"plugins":    []interface{}{rawConfig},
+	}
+
+	b, err := json.Marshal(rawConfigList)
+	if err != nil {
+		return nil, err
+	}
+	return ConfListFromBytes(b)
+}