v1.0.0

features/dns/client.go

@@ -0,0 +1,59 @@
+package dns
+
+import (
+	"github.com/xtls/xray-core/v1/common/errors"
+	"github.com/xtls/xray-core/v1/common/net"
+	"github.com/xtls/xray-core/v1/common/serial"
+	"github.com/xtls/xray-core/v1/features"
+)
+
+// Client is a Xray feature for querying DNS information.
+//
+// xray:api:stable
+type Client interface {
+	features.Feature
+
+	// LookupIP returns IP address for the given domain. IPs may contain IPv4 and/or IPv6 addresses.
+	LookupIP(domain string) ([]net.IP, error)
+}
+
+// IPv4Lookup is an optional feature for querying IPv4 addresses only.
+//
+// xray:api:beta
+type IPv4Lookup interface {
+	LookupIPv4(domain string) ([]net.IP, error)
+}
+
+// IPv6Lookup is an optional feature for querying IPv6 addresses only.
+//
+// xray:api:beta
+type IPv6Lookup interface {
+	LookupIPv6(domain string) ([]net.IP, error)
+}
+
+// ClientType returns the type of Client interface. Can be used for implementing common.HasType.
+//
+// xray:api:beta
+func ClientType() interface{} {
+	return (*Client)(nil)
+}
+
+// ErrEmptyResponse indicates that DNS query succeeded but no answer was returned.
+var ErrEmptyResponse = errors.New("empty response")
+
+type RCodeError uint16
+
+func (e RCodeError) Error() string {
+	return serial.Concat("rcode: ", uint16(e))
+}
+
+func RCodeFromError(err error) uint16 {
+	if err == nil {
+		return 0
+	}
+	cause := errors.Cause(err)
+	if r, ok := cause.(RCodeError); ok {
+		return uint16(r)
+	}
+	return 0
+}

features/dns/localdns/client.go

@@ -0,0 +1,80 @@
+package localdns
+
+import (
+	"github.com/xtls/xray-core/v1/common/net"
+	"github.com/xtls/xray-core/v1/features/dns"
+)
+
+// Client is an implementation of dns.Client, which queries localhost for DNS.
+type Client struct{}
+
+// Type implements common.HasType.
+func (*Client) Type() interface{} {
+	return dns.ClientType()
+}
+
+// Start implements common.Runnable.
+func (*Client) Start() error { return nil }
+
+// Close implements common.Closable.
+func (*Client) Close() error { return nil }
+
+// LookupIP implements Client.
+func (*Client) LookupIP(host string) ([]net.IP, error) {
+	ips, err := net.LookupIP(host)
+	if err != nil {
+		return nil, err
+	}
+	parsedIPs := make([]net.IP, 0, len(ips))
+	for _, ip := range ips {
+		parsed := net.IPAddress(ip)
+		if parsed != nil {
+			parsedIPs = append(parsedIPs, parsed.IP())
+		}
+	}
+	if len(parsedIPs) == 0 {
+		return nil, dns.ErrEmptyResponse
+	}
+	return parsedIPs, nil
+}
+
+// LookupIPv4 implements IPv4Lookup.
+func (c *Client) LookupIPv4(host string) ([]net.IP, error) {
+	ips, err := c.LookupIP(host)
+	if err != nil {
+		return nil, err
+	}
+	ipv4 := make([]net.IP, 0, len(ips))
+	for _, ip := range ips {
+		if len(ip) == net.IPv4len {
+			ipv4 = append(ipv4, ip)
+		}
+	}
+	if len(ipv4) == 0 {
+		return nil, dns.ErrEmptyResponse
+	}
+	return ipv4, nil
+}
+
+// LookupIPv6 implements IPv6Lookup.
+func (c *Client) LookupIPv6(host string) ([]net.IP, error) {
+	ips, err := c.LookupIP(host)
+	if err != nil {
+		return nil, err
+	}
+	ipv6 := make([]net.IP, 0, len(ips))
+	for _, ip := range ips {
+		if len(ip) == net.IPv6len {
+			ipv6 = append(ipv6, ip)
+		}
+	}
+	if len(ipv6) == 0 {
+		return nil, dns.ErrEmptyResponse
+	}
+	return ipv6, nil
+}
+
+// New create a new dns.Client that queries localhost for DNS.
+func New() *Client {
+	return &Client{}
+}