69 lines
1.6 KiB
Go
69 lines
1.6 KiB
Go
package resolver
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import (
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"context"
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"crypto/tls"
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"net"
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"net/http"
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"strings"
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)
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// PreferGo works on Windows since go1.19, https://github.com/golang/go/issues/33097
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func New(addr string, dialContext func(context.Context, string, string) (net.Conn, error)) *net.Resolver {
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switch {
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case strings.HasPrefix(addr, "tls://"):
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return &net.Resolver{
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PreferGo: true,
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Dial: func(ctx context.Context, _, _ string) (net.Conn, error) {
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address := withDefaultPort(addr[len("tls://"):], "853")
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conn, err := dialContext(ctx, "tcp", address)
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if err != nil {
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return nil, err
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}
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host, _, _ := net.SplitHostPort(address)
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c := tls.Client(conn, &tls.Config{
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ServerName: host,
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})
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return c, nil
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},
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}
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case strings.HasPrefix(addr, "https://"):
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c := &http.Client{
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Transport: &http.Transport{
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DialContext: dialContext,
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},
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}
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return &net.Resolver{
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PreferGo: true,
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Dial: func(ctx context.Context, _, _ string) (net.Conn, error) {
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return newDoHConn(ctx, c, addr)
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},
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}
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case addr != "":
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return &net.Resolver{
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PreferGo: true,
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Dial: func(ctx context.Context, _, _ string) (net.Conn, error) {
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address := addr
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network := "udp"
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if strings.HasPrefix(addr, "tcp://") || strings.HasPrefix(addr, "udp://") {
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network = addr[:len("tcp")]
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address = addr[len("tcp://"):]
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}
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return dialContext(ctx, network, withDefaultPort(address, "53"))
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},
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}
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default:
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return &net.Resolver{}
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}
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}
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func withDefaultPort(addr, port string) string {
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if _, _, err := net.SplitHostPort(addr); err == nil {
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return addr
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}
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return net.JoinHostPort(addr, port)
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}
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