56 lines
1.2 KiB
Go
56 lines
1.2 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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"strings"
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)
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func New(addr string) *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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d := tls.Dialer{}
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address := addr[len("tls://"):]
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return d.DialContext(ctx, "tcp", withDefaultPort(address, "853"))
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},
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}
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case strings.HasPrefix(addr, "https://"):
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return &net.Resolver{
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PreferGo: true,
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Dial: func(_ context.Context, _, _ string) (net.Conn, error) {
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conn := &dohConn{addr: addr}
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return conn, nil
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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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d := net.Dialer{}
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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 d.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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