package core import ( "net" "sync" "v2ray.com/core/common" ) // DNSClient is a V2Ray feature for querying DNS information. type DNSClient interface { Feature LookupIP(host string) ([]net.IP, error) } type syncDNSClient struct { sync.RWMutex DNSClient } func (d *syncDNSClient) LookupIP(host string) ([]net.IP, error) { d.RLock() defer d.RUnlock() if d.DNSClient == nil { return net.LookupIP(host) } return d.DNSClient.LookupIP(host) } func (d *syncDNSClient) Start() error { d.RLock() defer d.RUnlock() if d.DNSClient == nil { return nil } return d.DNSClient.Start() } func (d *syncDNSClient) Close() error { d.RLock() defer d.RUnlock() return common.Close(d.DNSClient) } func (d *syncDNSClient) Set(client DNSClient) { if client == nil { return } d.Lock() defer d.Unlock() common.Close(d.DNSClient) d.DNSClient = client }