112 lines
3.0 KiB
Go
112 lines
3.0 KiB
Go
package handlers
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import (
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"fmt"
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"log"
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"net"
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"strings"
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"github.com/miekg/dns"
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"github.com/play-with-docker/play-with-docker/config"
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)
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func DnsRequest(w dns.ResponseWriter, r *dns.Msg) {
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if len(r.Question) > 0 && config.NameFilter.MatchString(r.Question[0].Name) {
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// this is something we know about and we should try to handle
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question := r.Question[0].Name
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match := config.NameFilter.FindStringSubmatch(question)
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ip := strings.Replace(match[1], "-", ".", -1)
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m := new(dns.Msg)
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m.SetReply(r)
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m.Authoritative = true
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m.RecursionAvailable = true
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a, err := dns.NewRR(fmt.Sprintf("%s 60 IN A %s", question, ip))
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if err != nil {
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log.Fatal(err)
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}
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m.Answer = append(m.Answer, a)
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w.WriteMsg(m)
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return
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} else if len(r.Question) > 0 && config.AliasFilter.MatchString(r.Question[0].Name) {
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// this is something we know about and we should try to handle
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question := r.Question[0].Name
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match := config.AliasFilter.FindStringSubmatch(question)
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i := core.InstanceFindByAlias(match[2], match[1])
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m := new(dns.Msg)
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m.SetReply(r)
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m.Authoritative = true
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m.RecursionAvailable = true
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a, err := dns.NewRR(fmt.Sprintf("%s 60 IN A %s", question, i.IP))
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if err != nil {
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log.Fatal(err)
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}
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m.Answer = append(m.Answer, a)
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w.WriteMsg(m)
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return
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} else {
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if len(r.Question) > 0 {
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question := r.Question[0].Name
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if question == "localhost." {
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log.Printf("Not a PWD host. Asked for [localhost.] returning automatically [127.0.0.1]\n")
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m := new(dns.Msg)
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m.SetReply(r)
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m.Authoritative = true
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m.RecursionAvailable = true
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a, err := dns.NewRR(fmt.Sprintf("%s 60 IN A 127.0.0.1", question))
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if err != nil {
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log.Fatal(err)
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}
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m.Answer = append(m.Answer, a)
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w.WriteMsg(m)
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return
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}
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log.Printf("Not a PWD host. Looking up [%s]\n", question)
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ips, err := net.LookupIP(question)
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if err != nil {
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// we have no information about this and we are not a recursive dns server, so we just fail so the client can fallback to the next dns server it has configured
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w.Close()
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// dns.HandleFailed(w, r)
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return
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}
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log.Printf("Not a PWD host. Looking up [%s] got [%s]\n", question, ips)
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m := new(dns.Msg)
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m.SetReply(r)
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m.Authoritative = true
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m.RecursionAvailable = true
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for _, ip := range ips {
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ipv4 := ip.To4()
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if ipv4 == nil {
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a, err := dns.NewRR(fmt.Sprintf("%s 60 IN AAAA %s", question, ip.String()))
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if err != nil {
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log.Fatal(err)
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}
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m.Answer = append(m.Answer, a)
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} else {
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a, err := dns.NewRR(fmt.Sprintf("%s 60 IN A %s", question, ipv4.String()))
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if err != nil {
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log.Fatal(err)
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}
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m.Answer = append(m.Answer, a)
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}
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}
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w.WriteMsg(m)
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return
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} else {
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log.Printf("Not a PWD host. Got DNS without any question\n")
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// we have no information about this and we are not a recursive dns server, so we just fail so the client can fallback to the next dns server it has configured
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w.Close()
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// dns.HandleFailed(w, r)
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return
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}
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}
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}
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