DNS解析时，TCP 从哪个 IP 进来，就从哪个 IP 解析

chain.go

@@ -154,7 +154,7 @@ func (c *Chain) dialWithOptions(ctx context.Context, network, address string, op
 
 	ipAddr := address
 	if address != "" {
-		ipAddr = c.resolve(address, options.Resolver, options.Hosts)
+		ipAddr = c.resolve(ctx, address, options.Resolver, options.Hosts)
 		if ipAddr == "" {
 			return nil, fmt.Errorf("resolver: domain %s does not exists", address)
 		}
@@ -213,8 +213,7 @@ func (c *Chain) dialWithOptions(ctx context.Context, network, address string, op
 				}
 			}
 		} else if inboundIP != nil && strings.ToLower(network) == "udp" {
-			ip := inboundIP.(net.IP)
-			if !ip.IsLoopback() && !ip.IsPrivate() {
+			if ip, ok := inboundIP.(net.IP); ok && !ip.IsLoopback() {
 				d.LocalAddr = &net.UDPAddr{
 					IP: ip,
 				}
@@ -237,7 +236,7 @@ func (c *Chain) dialWithOptions(ctx context.Context, network, address string, op
 	return cc, nil
 }
 
-func (*Chain) resolve(addr string, resolver Resolver, hosts *Hosts) string {
+func (*Chain) resolve(ctx context.Context, addr string, resolver Resolver, hosts *Hosts) string {
 	host, port, err := net.SplitHostPort(addr)
 	if err != nil {
 		return addr
@@ -247,7 +246,7 @@ func (*Chain) resolve(addr string, resolver Resolver, hosts *Hosts) string {
 		return net.JoinHostPort(ip.String(), port)
 	}
 	if resolver != nil {
-		ips, err := resolver.Resolve(host)
+		ips, err := resolver.Resolve(ctx, host)
 		if err != nil {
 			log.Logf("[resolver] %s: %v", host, err)
 		}

resolver.go

@@ -171,7 +171,7 @@ type Resolver interface {
 	// Init initializes the Resolver instance.
 	Init(opts ...ResolverOption) error
 	// Resolve returns a slice of that host's IPv4 and IPv6 addresses.
-	Resolve(host string) ([]net.IP, error)
+	Resolve(ctx context.Context, host string) ([]net.IP, error)
 	// Exchange performs a synchronous query,
 	// It sends the message query and waits for a reply.
 	Exchange(ctx context.Context, query []byte) (reply []byte, err error)
@@ -268,7 +268,7 @@ func (r *resolver) copyServers() []NameServer {
 	return servers
 }
 
-func (r *resolver) Resolve(host string) (ips []net.IP, err error) {
+func (r *resolver) Resolve(ctx context.Context, host string) (ips []net.IP, err error) {
 	r.mux.RLock()
 	domain := r.domain
 	r.mux.RUnlock()
@@ -281,7 +281,6 @@ func (r *resolver) Resolve(host string) (ips []net.IP, err error) {
 		host = host + "." + domain
 	}
 
-	ctx := context.Background()
 	for _, ns := range r.copyServers() {
 		ips, err = r.resolve(ctx, ns.exchanger, host)
 		if err != nil {