forked from flannel-io/flannel
/
config.go
57 lines (48 loc) · 1.38 KB
/
config.go
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package subnet
import (
"encoding/json"
"errors"
"github.com/coreos/flannel/pkg/ip"
)
type Config struct {
Network ip.IP4Net
SubnetMin ip.IP4
SubnetMax ip.IP4
SubnetLen uint
Backend json.RawMessage
}
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")
}
return cfg, nil
}