feat: support tcp:// and tcp+udp:// for dns_upstream (#11)

control/dns_upstream.go

@@ -0,0 +1,89 @@
+/*
+ * SPDX-License-Identifier: AGPL-3.0-only
+ * Copyright (c) since 2023, mzz2017 <mzz@tuta.io>
+ */
+
+package control
+
+import (
+	"context"
+	"fmt"
+	"github.com/v2rayA/dae/common/consts"
+	"github.com/v2rayA/dae/common/netutils"
+	"github.com/v2rayA/dae/component/outbound/dialer"
+	"net/url"
+	"strconv"
+)
+
+type DnsUpstreamScheme string
+
+const (
+	DnsUpstreamScheme_TCP     DnsUpstreamScheme = "tcp"
+	DnsUpstreamScheme_UDP     DnsUpstreamScheme = "udp"
+	DnsUpstreamScheme_TCP_UDP DnsUpstreamScheme = "tcp+udp"
+)
+
+type DnsUpstraem struct {
+	Scheme   DnsUpstreamScheme
+	Hostname string
+	Port     uint16
+	*netutils.Ip46
+}
+
+func ResolveDnsUpstream(ctx context.Context, dnsUpstream *url.URL) (up *DnsUpstraem, err error) {
+	var _port string
+	switch DnsUpstreamScheme(dnsUpstream.Scheme) {
+	case DnsUpstreamScheme_TCP, DnsUpstreamScheme_UDP, DnsUpstreamScheme_TCP_UDP:
+		_port = dnsUpstream.Port()
+		if _port == "" {
+			_port = "53"
+		}
+	default:
+		return nil, fmt.Errorf("dns_upstream now only supports auto://, udp://, tcp:// and empty string (as-is)")
+	}
+
+	systemDns, err := netutils.SystemDns()
+	if err != nil {
+		return nil, err
+	}
+	port, err := strconv.ParseUint(dnsUpstream.Port(), 10, 16)
+	if err != nil {
+		return nil, fmt.Errorf("parse dns_upstream port: %v", err)
+	}
+	hostname := dnsUpstream.Hostname()
+	ip46, err := netutils.ParseIp46(ctx, dialer.SymmetricDirect, systemDns, hostname, false)
+	if err != nil {
+		return nil, fmt.Errorf("failed to resolve dns_upstream")
+	}
+	if !ip46.Ip4.IsValid() && !ip46.Ip6.IsValid() {
+		return nil, fmt.Errorf("dns_upstream has no record")
+	}
+	return &DnsUpstraem{
+		Scheme:   DnsUpstreamScheme(dnsUpstream.Scheme),
+		Hostname: hostname,
+		Port:     uint16(port),
+		Ip46:     ip46,
+	}, nil
+}
+
+func (u *DnsUpstraem) SupportedNetworks() (ipversions []consts.IpVersionStr, l4protos []consts.L4ProtoStr) {
+	if u.Ip4.IsValid() && u.Ip6.IsValid() {
+		ipversions = []consts.IpVersionStr{consts.IpVersionStr_4, consts.IpVersionStr_6}
+	} else {
+		if u.Ip4.IsValid() {
+			ipversions = []consts.IpVersionStr{consts.IpVersionStr_4}
+		} else {
+			ipversions = []consts.IpVersionStr{consts.IpVersionStr_6}
+		}
+	}
+	switch u.Scheme {
+	case DnsUpstreamScheme_TCP:
+		l4protos = []consts.L4ProtoStr{consts.L4ProtoStr_TCP}
+	case DnsUpstreamScheme_UDP:
+		l4protos = []consts.L4ProtoStr{consts.L4ProtoStr_UDP}
+	case DnsUpstreamScheme_TCP_UDP:
+		// UDP first.
+		l4protos = []consts.L4ProtoStr{consts.L4ProtoStr_UDP, consts.L4ProtoStr_TCP}
+	}
+	return ipversions, l4protos
+}