github.com/xraypb/Xray-core@v1.8.1/features/dns/localdns/client.go (about)

     1  package localdns
     2  
     3  import (
     4  	"github.com/xraypb/Xray-core/common/net"
     5  	"github.com/xraypb/Xray-core/features/dns"
     6  )
     7  
     8  // Client is an implementation of dns.Client, which queries localhost for DNS.
     9  type Client struct{}
    10  
    11  // Type implements common.HasType.
    12  func (*Client) Type() interface{} {
    13  	return dns.ClientType()
    14  }
    15  
    16  // Start implements common.Runnable.
    17  func (*Client) Start() error { return nil }
    18  
    19  // Close implements common.Closable.
    20  func (*Client) Close() error { return nil }
    21  
    22  // LookupIP implements Client.
    23  func (*Client) LookupIP(host string, option dns.IPOption) ([]net.IP, error) {
    24  	ips, err := net.LookupIP(host)
    25  	if err != nil {
    26  		return nil, err
    27  	}
    28  	parsedIPs := make([]net.IP, 0, len(ips))
    29  	ipv4 := make([]net.IP, 0, len(ips))
    30  	ipv6 := make([]net.IP, 0, len(ips))
    31  	for _, ip := range ips {
    32  		parsed := net.IPAddress(ip)
    33  		if parsed != nil {
    34  			parsedIPs = append(parsedIPs, parsed.IP())
    35  		}
    36  		if len(ip) == net.IPv4len {
    37  			ipv4 = append(ipv4, ip)
    38  		}
    39  		if len(ip) == net.IPv6len {
    40  			ipv6 = append(ipv6, ip)
    41  		}
    42  	}
    43  	switch {
    44  	case option.IPv4Enable && option.IPv6Enable:
    45  		if len(parsedIPs) > 0 {
    46  			return parsedIPs, nil
    47  		}
    48  	case option.IPv4Enable:
    49  		if len(ipv4) > 0 {
    50  			return ipv4, nil
    51  		}
    52  	case option.IPv6Enable:
    53  		if len(ipv6) > 0 {
    54  			return ipv6, nil
    55  		}
    56  	}
    57  	return nil, dns.ErrEmptyResponse
    58  }
    59  
    60  // New create a new dns.Client that queries localhost for DNS.
    61  func New() *Client {
    62  	return &Client{}
    63  }