forked from flannel-io/flannel
/
config.go
95 lines (81 loc) · 2.44 KB
/
config.go
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// Copyright 2015 flannel 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 subnet
import (
"encoding/json"
"errors"
"fmt"
"github.com/coreos/flannel/pkg/ip"
)
type Config struct {
Network ip.IP4Net
SubnetMin ip.IP4
SubnetMax ip.IP4
SubnetLen uint
BackendType string `json:"-"`
Backend json.RawMessage `json:",omitempty"`
}
func parseBackendType(be json.RawMessage) (string, error) {
var bt struct {
Type string
}
if len(be) == 0 {
return "udp", nil
} else {
if err := json.Unmarshal(be, &bt); err != nil {
return "", fmt.Errorf("error decoding Backend property of config: %v", err)
}
}
return bt.Type, nil
}
func ParseConfig(s string) (*Config, error) {
cfg := new(Config)
err := json.Unmarshal([]byte(s), cfg)
if err != nil {
return nil, err
}
if cfg.SubnetLen > 0 {
if cfg.SubnetLen < cfg.Network.PrefixLen {
return nil, errors.New("HostSubnet is larger network than Network")
}
} else {
// try to give each host a /24 but if the whole network
// is /24 or smaller, half the network
if cfg.Network.PrefixLen < 24 {
cfg.SubnetLen = 24
} else {
cfg.SubnetLen = cfg.Network.PrefixLen + 1
}
}
subnetSize := ip.IP4(1 << (32 - cfg.SubnetLen))
if cfg.SubnetMin == ip.IP4(0) {
// skip over the first subnet otherwise it causes problems. e.g.
// if Network is 10.100.0.0/16, having an interface with 10.0.0.0
// makes ping think it's a broadcast address (not sure why)
cfg.SubnetMin = cfg.Network.IP + subnetSize
} else if !cfg.Network.Contains(cfg.SubnetMin) {
return nil, errors.New("SubnetMin is not in the range of the Network")
}
if cfg.SubnetMax == ip.IP4(0) {
cfg.SubnetMax = cfg.Network.Next().IP - subnetSize
} else if !cfg.Network.Contains(cfg.SubnetMax) {
return nil, errors.New("SubnetMax is not in the range of the Network")
}
bt, err := parseBackendType(cfg.Backend)
if err != nil {
return nil, err
}
cfg.BackendType = bt
return cfg, nil
}