115 lines
2.7 KiB
Go
115 lines
2.7 KiB
Go
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package resolvers
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import (
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"crypto/tls"
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"errors"
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"fmt"
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"io"
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"os"
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"time"
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"github.com/lucas-clemente/quic-go"
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"github.com/miekg/dns"
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"github.com/sirupsen/logrus"
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)
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// DOQResolver represents the config options for setting up a DOQ based resolver.
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type DOQResolver struct {
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tls *tls.Config
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server string
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resolverOptions Options
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}
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// NewDOQResolver accepts a nameserver address and configures a DOQ based resolver.
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func NewDOQResolver(server string, resolverOpts Options) (Resolver, error) {
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return &DOQResolver{
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tls: &tls.Config{
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NextProtos: []string{"doq-i02", "doq-i00", "dq", "doq"},
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},
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server: server,
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resolverOptions: resolverOpts,
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}, nil
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}
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// Lookup takes a dns.Question and sends them to DNS Server.
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// It parses the Response from the server in a custom output format.
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func (r *DOQResolver) Lookup(question dns.Question) (Response, error) {
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var (
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rsp Response
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messages = prepareMessages(question, r.resolverOptions.Ndots, r.resolverOptions.SearchList)
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)
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session, err := quic.DialAddr(r.server, r.tls, nil)
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if err != nil {
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return rsp, err
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}
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defer session.CloseWithError(quic.ApplicationErrorCode(quic.NoError), "")
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for _, msg := range messages {
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r.resolverOptions.Logger.WithFields(logrus.Fields{
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"domain": msg.Question[0].Name,
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"ndots": r.resolverOptions.Ndots,
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"nameserver": r.server,
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}).Debug("Attempting to resolve")
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// get the DNS Message in wire format.
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var b []byte
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b, err = msg.Pack()
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if err != nil {
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return rsp, err
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}
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now := time.Now()
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var stream quic.Stream
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stream, err = session.OpenStream()
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if err != nil {
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return rsp, err
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}
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// Make a QUIC request to the DNS server with the DNS message as wire format bytes in the body.
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_, err = stream.Write(b)
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_ = stream.Close()
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if err != nil {
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return rsp, fmt.Errorf("send query error: %w", err)
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}
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err = stream.SetDeadline(time.Now().Add(r.resolverOptions.Timeout))
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if err != nil {
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return rsp, err
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}
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var buf []byte
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buf, err = io.ReadAll(stream)
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if err != nil {
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if errors.Is(err, os.ErrDeadlineExceeded) {
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return rsp, fmt.Errorf("timeout")
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}
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return rsp, err
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}
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rtt := time.Since(now)
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err = msg.Unpack(buf)
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if err != nil {
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return rsp, err
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}
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// pack questions in output.
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for _, q := range msg.Question {
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ques := Question{
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Name: q.Name,
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Class: dns.ClassToString[q.Qclass],
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Type: dns.TypeToString[q.Qtype],
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}
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rsp.Questions = append(rsp.Questions, ques)
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}
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// get the authorities and answers.
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output := parseMessage(&msg, rtt, r.server)
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rsp.Authorities = output.Authorities
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rsp.Answers = output.Answers
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if len(output.Answers) > 0 {
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// stop iterating the searchlist.
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break
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}
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}
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return rsp, nil
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}
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