github.com/xraypb/xray-core@v1.6.6/features/routing/dns/context.go (about)

     1  package dns
     2  
     3  //go:generate go run github.com/xraypb/xray-core/common/errors/errorgen
     4  
     5  import (
     6  	"github.com/xraypb/xray-core/common/net"
     7  	"github.com/xraypb/xray-core/features/dns"
     8  	"github.com/xraypb/xray-core/features/routing"
     9  )
    10  
    11  // ResolvableContext is an implementation of routing.Context, with domain resolving capability.
    12  type ResolvableContext struct {
    13  	routing.Context
    14  	dnsClient   dns.Client
    15  	resolvedIPs []net.IP
    16  }
    17  
    18  // GetTargetIPs overrides original routing.Context's implementation.
    19  func (ctx *ResolvableContext) GetTargetIPs() []net.IP {
    20  	if len(ctx.resolvedIPs) > 0 {
    21  		return ctx.resolvedIPs
    22  	}
    23  
    24  	if domain := ctx.GetTargetDomain(); len(domain) != 0 {
    25  		ips, err := ctx.dnsClient.LookupIP(domain, dns.IPOption{
    26  			IPv4Enable: true,
    27  			IPv6Enable: true,
    28  			FakeEnable: false,
    29  		})
    30  		if err == nil {
    31  			ctx.resolvedIPs = ips
    32  			return ips
    33  		}
    34  		newError("resolve ip for ", domain).Base(err).WriteToLog()
    35  	}
    36  
    37  	if ips := ctx.Context.GetTargetIPs(); len(ips) != 0 {
    38  		return ips
    39  	}
    40  
    41  	return nil
    42  }
    43  
    44  // ContextWithDNSClient creates a new routing context with domain resolving capability.
    45  // Resolved domain IPs can be retrieved by GetTargetIPs().
    46  func ContextWithDNSClient(ctx routing.Context, client dns.Client) routing.Context {
    47  	return &ResolvableContext{Context: ctx, dnsClient: client}
    48  }