Peter Kurfer
108444e094
- remove plugin API due to incompatibility issues - add Docker build to GitHub Actions - add custom container friendly config file
75 lines
1.6 KiB
Go
75 lines
1.6 KiB
Go
package dns_mock
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import (
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"encoding/binary"
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"github.com/spf13/viper"
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"math"
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"math/rand"
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"net"
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"unsafe"
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)
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const (
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randomIPStrategyName = "random"
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incrementalIPStrategyName = "incremental"
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startIPConfigKey = "startIP"
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)
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var (
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fallbackStrategies map[string]ResolverFactory
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)
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type ResolverFactory func(conf *viper.Viper) ResolverFallback
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func init() {
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fallbackStrategies = make(map[string]ResolverFactory)
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fallbackStrategies[incrementalIPStrategyName] = func(conf *viper.Viper) ResolverFallback {
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return &incrementalIPFallback{
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latestIp: ipToInt32(net.ParseIP(conf.GetString(startIPConfigKey))),
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}
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}
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fallbackStrategies[randomIPStrategyName] = func(conf *viper.Viper) ResolverFallback {
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return &randomIPFallback{}
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}
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}
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func CreateResolverFallback(name string, config *viper.Viper) ResolverFallback {
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if factory, ok := fallbackStrategies[name]; ok {
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return factory(config)
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} else {
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return fallbackStrategies[randomIPStrategyName](config)
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}
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}
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type ResolverFallback interface {
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GetIP() net.IP
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}
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type incrementalIPFallback struct {
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latestIp uint32
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}
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func (i *incrementalIPFallback) GetIP() net.IP {
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if i.latestIp < math.MaxInt32 {
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i.latestIp += 1
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}
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return uint32ToIP(i.latestIp)
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}
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type randomIPFallback struct {
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}
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func (randomIPFallback) GetIP() net.IP {
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return uint32ToIP(uint32(rand.Int31()))
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}
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func uint32ToIP(i uint32) net.IP {
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bytes := (*[4]byte)(unsafe.Pointer(&i))[:]
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return net.IPv4(bytes[3], bytes[2], bytes[1], bytes[0])
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}
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func ipToInt32(ip net.IP) uint32 {
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v4 := ip.To4()
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result := binary.BigEndian.Uint32(v4)
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return result
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}
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