136 lines
2.7 KiB
Go
136 lines
2.7 KiB
Go
package dns
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import (
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"context"
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"crypto/tls"
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"errors"
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"fmt"
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"net"
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"time"
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"github.com/Dreamacro/clash/common/cache"
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"github.com/Dreamacro/clash/common/picker"
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"github.com/Dreamacro/clash/log"
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D "github.com/miekg/dns"
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)
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func putMsgToCache(c *cache.LruCache, key string, msg *D.Msg) {
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var ttl uint32
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switch {
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case len(msg.Answer) != 0:
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ttl = msg.Answer[0].Header().Ttl
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case len(msg.Ns) != 0:
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ttl = msg.Ns[0].Header().Ttl
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case len(msg.Extra) != 0:
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ttl = msg.Extra[0].Header().Ttl
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default:
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log.Debugln("[DNS] response msg empty: %#v", msg)
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return
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}
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c.SetWithExpire(key, msg.Copy(), time.Now().Add(time.Second*time.Duration(ttl)))
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}
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func setMsgTTL(msg *D.Msg, ttl uint32) {
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for _, answer := range msg.Answer {
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answer.Header().Ttl = ttl
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}
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for _, ns := range msg.Ns {
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ns.Header().Ttl = ttl
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}
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for _, extra := range msg.Extra {
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extra.Header().Ttl = ttl
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}
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}
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func isIPRequest(q D.Question) bool {
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return q.Qclass == D.ClassINET && (q.Qtype == D.TypeA || q.Qtype == D.TypeAAAA)
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}
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func transform(servers []NameServer, resolver *Resolver) []dnsClient {
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ret := []dnsClient{}
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for _, s := range servers {
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switch s.Net {
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case "https":
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ret = append(ret, newDoHClient(s.Addr, s.Interface, resolver))
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continue
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case "dhcp":
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ret = append(ret, newDHCPClient(s.Addr))
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continue
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}
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host, port, _ := net.SplitHostPort(s.Addr)
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ret = append(ret, &client{
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Client: &D.Client{
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Net: s.Net,
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TLSConfig: &tls.Config{
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ServerName: host,
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},
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UDPSize: 4096,
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Timeout: 5 * time.Second,
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},
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port: port,
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host: host,
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iface: s.Interface,
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r: resolver,
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})
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}
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return ret
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}
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func handleMsgWithEmptyAnswer(r *D.Msg) *D.Msg {
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msg := &D.Msg{}
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msg.Answer = []D.RR{}
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msg.SetRcode(r, D.RcodeSuccess)
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msg.Authoritative = true
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msg.RecursionAvailable = true
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return msg
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}
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func msgToIP(msg *D.Msg) []net.IP {
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ips := []net.IP{}
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for _, answer := range msg.Answer {
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switch ans := answer.(type) {
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case *D.AAAA:
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ips = append(ips, ans.AAAA)
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case *D.A:
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ips = append(ips, ans.A)
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}
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}
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return ips
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}
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func batchExchange(ctx context.Context, clients []dnsClient, m *D.Msg) (msg *D.Msg, err error) {
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fast, ctx := picker.WithContext(ctx)
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for _, client := range clients {
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r := client
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fast.Go(func() (any, error) {
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m, err := r.ExchangeContext(ctx, m)
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if err != nil {
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return nil, err
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} else if m.Rcode == D.RcodeServerFailure || m.Rcode == D.RcodeRefused {
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return nil, errors.New("server failure")
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}
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return m, nil
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})
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}
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elm := fast.Wait()
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if elm == nil {
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err := errors.New("all DNS requests failed")
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if fErr := fast.Error(); fErr != nil {
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err = fmt.Errorf("%w, first error: %s", err, fErr.Error())
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}
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return nil, err
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}
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msg = elm.(*D.Msg)
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return
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}
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