refactor: only export LookupNetIP for resolver package

conf.go

@@ -6,6 +6,8 @@ import (
 	"encoding/hex"
 	"fmt"
 	"net"
+	"net/netip"
+	"strconv"
 	"time"
 
 	"github.com/zhsj/wghttp/internal/resolver"
@@ -13,13 +15,14 @@ import (
 )
 
 type peer struct {
-	dialer *net.Dialer
+	resolver *resolver.Resolver
 
 	pubKey string
 	psk    string
 
-	addr   string
+	host string
-	ipPort string
+	ip   netip.Addr
+	port uint16
 }
 
 func newPeerEndpoint() (*peer, error) {
@@ -33,30 +36,45 @@ func newPeerEndpoint() (*peer, error) {
 	}
 
 	p := &peer{
-		dialer: &net.Dialer{
-			Resolver: resolver.New(
-				opts.ResolveDNS,
-				func(ctx context.Context, network, address string) (net.Conn, error) {
-					netConn, err := (&net.Dialer{}).DialContext(ctx, network, address)
-					logger.Verbosef("Using %s to resolve peer endpoint: %v", opts.ResolveDNS, err)
-					return netConn, err
-				},
-			),
-		},
 		pubKey: hex.EncodeToString(pubKey),
 		psk:    hex.EncodeToString(psk),
-		addr:   opts.PeerEndpoint,
 	}
-	p.ipPort, err = p.resolveAddr()
+	host, port, err := net.SplitHostPort(opts.PeerEndpoint)
 	if err != nil {
-		return nil, fmt.Errorf("resolve peer endpoint: %w", err)
+		return nil, fmt.Errorf("parse peer endpoint: %w", err)
 	}
+	port16, err := strconv.ParseUint(port, 10, 16)
+	if err != nil {
+		return nil, fmt.Errorf("parse peer endpoint port: %w", err)
+	}
+	p.host = host
+	p.port = uint16(port16)
+
+	p.ip, err = netip.ParseAddr(p.host)
+	if err == nil {
+		return p, nil
+	}
+
+	p.resolver = resolver.New(
+		opts.ResolveDNS,
+		func(ctx context.Context, network, address string) (net.Conn, error) {
+			netConn, err := (&net.Dialer{}).DialContext(ctx, network, address)
+			logger.Verbosef("Using %s to resolve peer endpoint: %v", opts.ResolveDNS, err)
+			return netConn, err
+		},
+	)
+
+	p.ip, err = p.resolveHost()
+	if err != nil {
+		return nil, fmt.Errorf("resolve peer endpoint ip: %w", err)
+	}
+
 	return p, err
 }
 
 func (p *peer) initConf() string {
 	conf := "public_key=" + p.pubKey + "\n"
-	conf += "endpoint=" + p.ipPort + "\n"
+	conf += "endpoint=" + netip.AddrPortFrom(p.ip, p.port).String() + "\n"
 	conf += "allowed_ip=0.0.0.0/0\n"
 	conf += "allowed_ip=::/0\n"
 
@@ -71,30 +89,38 @@ func (p *peer) initConf() string {
 }
 
 func (p *peer) updateConf() (string, bool) {
-	newIPPort, err := p.resolveAddr()
+	newIP, err := p.resolveHost()
 	if err != nil {
 		logger.Verbosef("Resolve peer endpoint: %v", err)
 		return "", false
 	}
-	if p.ipPort == newIPPort {
+	if p.ip == newIP {
 		return "", false
 	}
-	p.ipPort = newIPPort
+	p.ip = newIP
-	logger.Verbosef("PeerEndpoint is changed to: %s", p.ipPort)
+	logger.Verbosef("PeerEndpoint is changed to: %s", p.ip)
 
 	conf := "public_key=" + p.pubKey + "\n"
 	conf += "update_only=true\n"
-	conf += "endpoint=" + p.ipPort + "\n"
+	conf += "endpoint=" + netip.AddrPortFrom(p.ip, p.port).String() + "\n"
 	return conf, true
 }
 
-func (p *peer) resolveAddr() (string, error) {
+func (p *peer) resolveHost() (netip.Addr, error) {
-	c, err := p.dialer.Dial("udp", p.addr)
+	ips, err := p.resolver.LookupNetIP(context.Background(), "ip", p.host)
 	if err != nil {
-		return "", err
+		return netip.Addr{}, fmt.Errorf("resolve ip for %s: %w", p.host, err)
 	}
-	defer c.Close()
+	for _, ip := range ips {
-	return c.RemoteAddr().String(), nil
+		conn, err := net.DialUDP("udp", nil, net.UDPAddrFromAddrPort(netip.AddrPortFrom(ip, p.port)))
+		if err == nil {
+			conn.Close()
+			return ip, nil
+		} else {
+			logger.Verbosef("Dial %s: %s", ip, err)
+		}
+	}
+	return netip.Addr{}, fmt.Errorf("no available ip for %s", p.host)
 }
 
 func ipcSet(dev *device.Device) error {
@@ -118,7 +144,7 @@ func ipcSet(dev *device.Device) error {
 		return err
 	}
 
-	if peer.addr != peer.ipPort {
+	if peer.resolver != nil {
 		go func() {
 			c := time.Tick(opts.ResolveInterval)
 

internal/proxy/proxy.go

@@ -51,7 +51,7 @@ func dialWithDNS(dial dialer, dns string) dialer {
 			}
 		}
 
-		ips, err := resolv.LookupHost(ctx, host)
+		ips, err := resolv.LookupNetIP(ctx, network, host)
 		if err != nil {
 			return nil, err
 		}
@@ -61,7 +61,7 @@ func dialWithDNS(dial dialer, dns string) dialer {
 			conn    net.Conn
 		)
 		for _, ip := range ips {
-			addr := net.JoinHostPort(ip, port)
+			addr := net.JoinHostPort(ip.String(), port)
 			conn, lastErr = dial(ctx, network, addr)
 			if lastErr == nil {
 				return conn, nil

internal/resolver/resolver.go

@@ -3,61 +3,109 @@ package resolver
 import (
 	"context"
 	"crypto/tls"
+	"errors"
 	"net"
 	"net/http"
+	"net/netip"
 	"strings"
 )
 
-// PreferGo works on Windows since go1.19, https://github.com/golang/go/issues/33097
+var errNotRetry = errors.New("not retry")
 
-func New(addr string, dialContext func(context.Context, string, string) (net.Conn, error)) *net.Resolver {
+type Resolver struct {
+	sysAddr, addr string
+	network       string
+	tlsConfig     *tls.Config
+	httpClient    *http.Client
+
+	r *net.Resolver
+}
+
+func (r *Resolver) LookupNetIP(ctx context.Context, network, host string) ([]netip.Addr, error) {
+	ipNetwork := network
+	switch network {
+	case "tcp", "udp":
+		ipNetwork = "ip"
+	case "tcp4", "udp4":
+		ipNetwork = "ip4"
+	case "tcp6", "udp6":
+		ipNetwork = "ip6"
+	}
+
+	return r.r.LookupNetIP(ctx, ipNetwork, host)
+}
+
+func New(dns string, dial func(ctx context.Context, network, address string) (net.Conn, error)) *Resolver {
+	r := &Resolver{}
 	switch {
-	case strings.HasPrefix(addr, "tls://"):
+	case strings.HasPrefix(dns, "tls://"):
-		return &net.Resolver{
+		r.addr = withDefaultPort(dns[len("tls://"):], "853")
+		host, _, _ := net.SplitHostPort(r.addr)
+		r.tlsConfig = &tls.Config{
+			ServerName: host,
+		}
+		r.r = &net.Resolver{
 			PreferGo: true,
-			Dial: func(ctx context.Context, _, _ string) (net.Conn, error) {
+			Dial: func(ctx context.Context, _, address string) (net.Conn, error) {
-				address := withDefaultPort(addr[len("tls://"):], "853")
+				if r.sysAddr == "" {
-				conn, err := dialContext(ctx, "tcp", address)
+					r.sysAddr = address
+				}
+				if r.sysAddr != address {
+					return nil, errNotRetry
+				}
+				conn, err := dial(ctx, "tcp", r.addr)
 				if err != nil {
 					return nil, err
 				}
-				host, _, _ := net.SplitHostPort(address)
+				return tls.Client(conn, r.tlsConfig), nil
-				c := tls.Client(conn, &tls.Config{
-					ServerName: host,
-				})
-				return c, nil
 			},
 		}
-	case strings.HasPrefix(addr, "https://"):
+	case strings.HasPrefix(dns, "https://"):
-		c := &http.Client{
+		r.httpClient = &http.Client{
 			Transport: &http.Transport{
-				DialContext: dialContext,
+				DialContext: dial,
 			},
 		}
-		return &net.Resolver{
+		r.r = &net.Resolver{
 			PreferGo: true,
-			Dial: func(ctx context.Context, _, _ string) (net.Conn, error) {
+			Dial: func(ctx context.Context, _, address string) (net.Conn, error) {
-				return newDoHConn(ctx, c, addr)
+				if r.sysAddr == "" {
-			},
+					r.sysAddr = address
-		}
+				}
-	case addr != "":
+				if r.sysAddr != address {
-		return &net.Resolver{
+					return nil, errNotRetry
-			PreferGo: true,
-			Dial: func(ctx context.Context, _, _ string) (net.Conn, error) {
-				address := addr
-				network := "udp"
-
-				if strings.HasPrefix(addr, "tcp://") || strings.HasPrefix(addr, "udp://") {
-					network = addr[:len("tcp")]
-					address = addr[len("tcp://"):]
 				}
 
-				return dialContext(ctx, network, withDefaultPort(address, "53"))
+				return newDoHConn(ctx, r.httpClient, dns)
+			},
+		}
+	case dns != "":
+		r.addr = dns
+		r.network = "udp"
+
+		if strings.HasPrefix(dns, "tcp://") || strings.HasPrefix(dns, "udp://") {
+			r.addr = dns[len("tcp://"):]
+			r.network = dns[:len("tcp")]
+		}
+		r.addr = withDefaultPort(r.addr, "53")
+
+		r.r = &net.Resolver{
+			PreferGo: true,
+			Dial: func(ctx context.Context, _, address string) (net.Conn, error) {
+				if r.sysAddr == "" {
+					r.sysAddr = address
+				}
+				if r.sysAddr != address {
+					return nil, errNotRetry
+				}
+
+				return dial(ctx, r.network, r.addr)
 			},
 		}
 	default:
-		return &net.Resolver{}
+		r.r = &net.Resolver{}
 	}
+	return r
 }
 
 func withDefaultPort(addr, port string) string {

internal/resolver/resolver_test.go

@@ -1,6 +1,7 @@
 package resolver
 
 import (
+	"context"
 	"net"
 	"testing"
 )
@@ -25,14 +26,13 @@ func TestResolve(t *testing.T) {
 		"https://223.5.5.5:443/dns-query",
 	} {
 		t.Run(server, func(t *testing.T) {
-			d := &net.Dialer{
+			r := New(server, (&net.Dialer{}).DialContext)
-				Resolver: New(server, (&net.Dialer{}).DialContext),
+			ips, err := r.LookupNetIP(context.TODO(), "ip4", "www.example.com")
-			}
+
-			c, err := d.Dial("tcp4", "www.example.com:80")
 			if err != nil {
 				t.Error(err)
 			} else {
-				t.Logf("got %s", c.RemoteAddr())
+				t.Logf("got %s", ips)
 			}
 		})
 	}