126 lines
2.2 KiB
Go
126 lines
2.2 KiB
Go
package dns
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import (
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"errors"
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"fmt"
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"net"
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"github.com/Dreamacro/clash/log"
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"github.com/miekg/dns"
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D "github.com/miekg/dns"
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)
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var (
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address string
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server = &Server{}
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dnsDefaultTTL uint32 = 600
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)
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type Server struct {
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*D.Server
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r *Resolver
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}
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func (s *Server) ServeDNS(w D.ResponseWriter, r *D.Msg) {
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if s.r.IsFakeIP() {
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msg, err := s.handleFakeIP(r)
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if err != nil {
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D.HandleFailed(w, r)
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return
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}
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msg.SetReply(r)
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w.WriteMsg(msg)
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return
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}
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msg, err := s.r.Exchange(r)
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if err != nil {
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if len(r.Question) > 0 {
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q := r.Question[0]
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qString := fmt.Sprintf("%s %s %s", q.Name, D.Class(q.Qclass).String(), D.Type(q.Qtype).String())
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log.Debugln("[DNS Server] Exchange %s failed: %v", qString, err)
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}
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D.HandleFailed(w, r)
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return
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}
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msg.SetReply(r)
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w.WriteMsg(msg)
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}
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func (s *Server) handleFakeIP(r *D.Msg) (msg *D.Msg, err error) {
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if len(r.Question) == 0 {
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err = errors.New("should have one question at least")
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return
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}
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q := r.Question[0]
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cache := s.r.cache.Get("fakeip:" + q.String())
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if cache != nil {
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msg = cache.(*D.Msg).Copy()
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setMsgTTL(msg, 1)
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return
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}
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var ip net.IP
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defer func() {
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if msg == nil {
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return
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}
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putMsgToCache(s.r.cache, "fakeip:"+q.String(), msg)
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putMsgToCache(s.r.cache, ip.String(), msg)
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setMsgTTL(msg, 1)
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}()
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rr := &D.A{}
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rr.Hdr = dns.RR_Header{Name: r.Question[0].Name, Rrtype: dns.TypeA, Class: dns.ClassINET, Ttl: dnsDefaultTTL}
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ip = s.r.pool.Get()
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rr.A = ip
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msg = r.Copy()
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msg.Answer = []D.RR{rr}
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return
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}
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func (s *Server) setReslover(r *Resolver) {
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s.r = r
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}
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func ReCreateServer(addr string, resolver *Resolver) error {
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if addr == address {
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server.setReslover(resolver)
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return nil
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}
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if server.Server != nil {
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server.Shutdown()
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address = ""
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}
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_, port, err := net.SplitHostPort(addr)
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if port == "0" || port == "" || err != nil {
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return nil
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}
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udpAddr, err := net.ResolveUDPAddr("udp", addr)
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if err != nil {
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return err
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}
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p, err := net.ListenUDP("udp", udpAddr)
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if err != nil {
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return err
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}
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address = addr
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server = &Server{r: resolver}
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server.Server = &D.Server{Addr: addr, PacketConn: p, Handler: server}
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go func() {
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server.ActivateAndServe()
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}()
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return nil
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}
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