70 lines
1.7 KiB
Go
70 lines
1.7 KiB
Go
package example
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import (
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"fmt"
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"github.com/miekg/dns"
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)
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func (e *exampleSolver) handleDNSRequest(w dns.ResponseWriter, req *dns.Msg) {
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msg := new(dns.Msg)
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msg.SetReply(req)
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switch req.Opcode {
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case dns.OpcodeQuery:
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for _, q := range msg.Question {
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if err := e.addDNSAnswer(q, msg, req); err != nil {
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msg.SetRcode(req, dns.RcodeServerFailure)
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break
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}
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}
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}
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w.WriteMsg(msg)
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}
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func (e *exampleSolver) addDNSAnswer(q dns.Question, msg *dns.Msg, req *dns.Msg) error {
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switch q.Qtype {
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// Always return loopback for any A query
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case dns.TypeA:
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rr, err := dns.NewRR(fmt.Sprintf("%s 5 IN A 127.0.0.1", q.Name))
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if err != nil {
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return err
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}
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msg.Answer = append(msg.Answer, rr)
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return nil
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// TXT records are the only important record for ACME dns-01 challenges
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case dns.TypeTXT:
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e.RLock()
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record, found := e.txtRecords[q.Name]
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e.RUnlock()
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if !found {
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msg.SetRcode(req, dns.RcodeNameError)
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return nil
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}
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rr, err := dns.NewRR(fmt.Sprintf("%s 5 IN TXT %s", q.Name, record))
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if err != nil {
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return err
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}
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msg.Answer = append(msg.Answer, rr)
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return nil
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// NS and SOA are for authoritative lookups, return obviously invalid data
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case dns.TypeNS:
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rr, err := dns.NewRR(fmt.Sprintf("%s 5 IN NS ns.example-acme-webook.invalid.", q.Name))
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if err != nil {
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return err
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}
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msg.Answer = append(msg.Answer, rr)
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return nil
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case dns.TypeSOA:
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rr, err := dns.NewRR(fmt.Sprintf("%s 5 IN SOA %s 20 5 5 5 5", "ns.example-acme-webook.invalid.", "ns.example-acme-webook.invalid."))
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if err != nil {
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return err
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}
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msg.Answer = append(msg.Answer, rr)
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return nil
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default:
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return fmt.Errorf("unimplemented record type %v", q.Qtype)
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}
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}
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