github.com/v2fly/v2ray-core/v5@v5.16.2-0.20240507031116-8191faa6e095/app/dns/nameserver_fakedns.go (about)

     1  //go:build !confonly
     2  // +build !confonly
     3  
     4  package dns
     5  
     6  import (
     7  	"context"
     8  
     9  	core "github.com/v2fly/v2ray-core/v5"
    10  	"github.com/v2fly/v2ray-core/v5/common/net"
    11  	"github.com/v2fly/v2ray-core/v5/features/dns"
    12  )
    13  
    14  type FakeDNSServer struct {
    15  	fakeDNSEngine dns.FakeDNSEngine
    16  }
    17  
    18  func NewFakeDNSServer(fakeDNSEngine dns.FakeDNSEngine) *FakeDNSServer {
    19  	return &FakeDNSServer{fakeDNSEngine: fakeDNSEngine}
    20  }
    21  
    22  func (FakeDNSServer) Name() string {
    23  	return "fakedns"
    24  }
    25  
    26  func (f *FakeDNSServer) QueryIP(ctx context.Context, domain string, _ net.IP, opt dns.IPOption, _ bool) ([]net.IP, error) {
    27  	if !opt.FakeEnable {
    28  		return nil, nil // Returning empty ip record with no error will continue DNS lookup, effectively indicating that this server is disabled.
    29  	}
    30  	if f.fakeDNSEngine == nil {
    31  		if err := core.RequireFeatures(ctx, func(fd dns.FakeDNSEngine) {
    32  			f.fakeDNSEngine = fd
    33  		}); err != nil {
    34  			return nil, newError("Unable to locate a fake DNS Engine").Base(err).AtError()
    35  		}
    36  	}
    37  	var ips []net.Address
    38  	if fkr0, ok := f.fakeDNSEngine.(dns.FakeDNSEngineRev0); ok {
    39  		ips = fkr0.GetFakeIPForDomain3(domain, opt.IPv4Enable, opt.IPv6Enable)
    40  	} else {
    41  		ips = filterIP(f.fakeDNSEngine.GetFakeIPForDomain(domain), opt)
    42  	}
    43  
    44  	netIP, err := toNetIP(ips)
    45  	if err != nil {
    46  		return nil, newError("Unable to convert IP to net ip").Base(err).AtError()
    47  	}
    48  
    49  	newError(f.Name(), " got answer: ", domain, " -> ", ips).AtInfo().WriteToLog()
    50  
    51  	if len(netIP) > 0 {
    52  		return netIP, nil
    53  	}
    54  	return nil, dns.ErrEmptyResponse
    55  }
    56  
    57  func isFakeDNS(server Server) bool {
    58  	_, ok := server.(*FakeDNSServer)
    59  	return ok
    60  }