f907311cdf
Rename the old Context to State and use context.Context in the middleware for intra-middleware communication and more.
86 lines
2.1 KiB
Go
86 lines
2.1 KiB
Go
// Reflect provides middleware that reflects back some client properties.
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// This is the default middleware when Caddy is run without configuration.
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//
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// The left-most label must be `who`.
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// When queried for type A (resp. AAAA), it sends back the IPv4 (resp. v6) address.
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// In the additional section the port number and transport are shown.
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// Basic use pattern:
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//
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// dig @localhost -p 1053 who.miek.nl A
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//
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// ;; ANSWER SECTION:
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// who.miek.nl. 0 IN A 127.0.0.1
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//
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// ;; ADDITIONAL SECTION:
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// who.miek.nl. 0 IN TXT "Port: 56195 (udp)"
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package reflect
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import (
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"errors"
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"net"
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"strings"
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"golang.org/x/net/context"
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"github.com/miekg/coredns/middleware"
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"github.com/miekg/dns"
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)
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type Reflect struct {
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Next middleware.Handler
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}
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func (rl Reflect) ServeDNS(ctx context.Context, w dns.ResponseWriter, r *dns.Msg) (int, error) {
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state := middleware.State{Req: r, W: w}
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class := r.Question[0].Qclass
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qname := r.Question[0].Name
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i, ok := dns.NextLabel(qname, 0)
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if strings.ToLower(qname[:i]) != who || ok {
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err := state.ErrorMessage(dns.RcodeFormatError)
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w.WriteMsg(err)
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return dns.RcodeFormatError, errors.New(dns.RcodeToString[dns.RcodeFormatError])
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}
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answer := new(dns.Msg)
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answer.SetReply(r)
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answer.Compress = true
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answer.Authoritative = true
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ip := state.IP()
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proto := state.Proto()
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port, _ := state.Port()
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family := state.Family()
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var rr dns.RR
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switch family {
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case 1:
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rr = new(dns.A)
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rr.(*dns.A).Hdr = dns.RR_Header{Name: qname, Rrtype: dns.TypeA, Class: class, Ttl: 0}
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rr.(*dns.A).A = net.ParseIP(ip).To4()
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case 2:
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rr = new(dns.AAAA)
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rr.(*dns.AAAA).Hdr = dns.RR_Header{Name: qname, Rrtype: dns.TypeAAAA, Class: class, Ttl: 0}
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rr.(*dns.AAAA).AAAA = net.ParseIP(ip)
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}
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t := new(dns.TXT)
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t.Hdr = dns.RR_Header{Name: qname, Rrtype: dns.TypeTXT, Class: class, Ttl: 0}
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t.Txt = []string{"Port: " + port + " (" + proto + ")"}
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switch state.Type() {
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case "TXT":
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answer.Answer = append(answer.Answer, t)
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answer.Extra = append(answer.Extra, rr)
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default:
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fallthrough
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case "AAAA", "A":
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answer.Answer = append(answer.Answer, rr)
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answer.Extra = append(answer.Extra, t)
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}
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w.WriteMsg(answer)
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return 0, nil
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}
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const who = "who."
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