feat: use internal resolver for wg network

internal/proxy/proxy.go

@@ -0,0 +1,94 @@
+package proxy
+
+import (
+	"context"
+	"encoding/json"
+	"net"
+	"net/http"
+
+	"github.com/zhsj/wghttp/internal/resolver"
+	"github.com/zhsj/wghttp/internal/third_party/tailscale/httpproxy"
+	"github.com/zhsj/wghttp/internal/third_party/tailscale/proxymux"
+	"github.com/zhsj/wghttp/internal/third_party/tailscale/socks5"
+)
+
+type dialer func(ctx context.Context, network, address string) (net.Conn, error)
+
+type Proxy struct {
+	Dial  dialer
+	DNS   string
+	Stats func() (any, error)
+}
+
+func statsHandler(next http.Handler, stats func() (any, error)) http.Handler {
+	return http.HandlerFunc(func(rw http.ResponseWriter, r *http.Request) {
+		if r.URL.Host != "" || r.URL.Path != "/stats" {
+			next.ServeHTTP(rw, r)
+			return
+		}
+		s, err := stats()
+		if err != nil {
+			rw.WriteHeader(http.StatusInternalServerError)
+		} else {
+			resp, _ := json.MarshalIndent(s, "", "  ")
+			rw.Header().Set("Content-Type", "application/json")
+			_, _ = rw.Write(append(resp, '\n'))
+		}
+	})
+}
+
+func dialWithDNS(dial dialer, dns string) dialer {
+	resolv := resolver.New(dns, dial)
+
+	return func(ctx context.Context, network, address string) (net.Conn, error) {
+		host, port, err := net.SplitHostPort(address)
+		if err != nil {
+			return nil, err
+		}
+		if err == nil {
+			if ip := net.ParseIP(host); ip != nil {
+				return dial(ctx, network, address)
+			}
+		}
+
+		ips, err := resolv.LookupHost(ctx, host)
+		if err != nil {
+			return nil, err
+		}
+
+		var (
+			lastErr error
+			conn    net.Conn
+		)
+		for _, ip := range ips {
+			addr := net.JoinHostPort(ip, port)
+			conn, lastErr = dial(ctx, network, addr)
+			if lastErr == nil {
+				return conn, nil
+			}
+		}
+		return nil, lastErr
+	}
+}
+
+func (p Proxy) Serve(ln net.Listener) {
+	d := dialWithDNS(p.Dial, p.DNS)
+
+	socksListener, httpListener := proxymux.SplitSOCKSAndHTTP(ln)
+
+	httpProxy := &http.Server{Handler: statsHandler(httpproxy.Handler(d), p.Stats)}
+	socksProxy := &socks5.Server{Dialer: d}
+
+	errc := make(chan error, 2)
+	go func() {
+		if err := httpProxy.Serve(httpListener); err != nil {
+			errc <- err
+		}
+	}()
+	go func() {
+		if err := socksProxy.Serve(socksListener); err != nil {
+			errc <- err
+		}
+	}()
+	<-errc
+}