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https://github.com/coredns/coredns.git
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898b1ef316
* server: actually scrub response Did all the worked, hooked it up wrongly :( This also needs test, but those are hard(er) because we only receive packets after they have been decoded; i.e. we never see the wirefmt. Signed-off-by: Miek Gieben <miek@miek.nl> * Add tests Add a test for checking is compression pointers are set in the packet. This also adds an undocumented 'large' feature to the erratic plugin to send large responses that should be compressed. Commenting the Scrub out in server results in: === RUN TestCompressScrub --- FAIL: TestCompressScrub (0.00s) compression_scrub_test.go:41: Expected returned packet to be < 512, got 839 FAIL exit status 1 FAIL github.com/coredns/coredns/test 0.036s Actually checking the size might be easier, but lets be thorough here and check the pointers them selves. Signed-off-by: Miek Gieben <miek@miek.nl> * Fix tests Signed-off-by: Miek Gieben <miek@miek.nl> * plugin erratic: fix e.large always put an rr in the reply, fix e.large in erractic and add test to check for it. Signed-off-by: Miek Gieben <miek@miek.nl>
113 lines
2.1 KiB
Go
113 lines
2.1 KiB
Go
// Package erratic implements a plugin that returns erratic answers (delayed, dropped).
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package erratic
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import (
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"context"
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"sync/atomic"
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"time"
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"github.com/coredns/coredns/request"
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"github.com/miekg/dns"
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)
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// Erratic is a plugin that returns erratic responses to each client.
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type Erratic struct {
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drop uint64
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delay uint64
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duration time.Duration
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truncate uint64
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large bool // undocumented feature; return large responses for A request (>512B, to test compression).
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q uint64 // counter of queries
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}
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// ServeDNS implements the plugin.Handler interface.
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func (e *Erratic) ServeDNS(ctx context.Context, w dns.ResponseWriter, r *dns.Msg) (int, error) {
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state := request.Request{W: w, Req: r}
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drop := false
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delay := false
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trunc := false
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queryNr := atomic.LoadUint64(&e.q)
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atomic.AddUint64(&e.q, 1)
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if e.drop > 0 && queryNr%e.drop == 0 {
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drop = true
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}
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if e.delay > 0 && queryNr%e.delay == 0 {
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delay = true
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}
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if e.truncate > 0 && queryNr&e.truncate == 0 {
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trunc = true
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}
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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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if trunc {
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m.Truncated = true
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}
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// small dance to copy rrA or rrAAAA into a non-pointer var that allows us to overwrite the ownername
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// in a non-racy way.
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switch state.QType() {
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case dns.TypeA:
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rr := *(rrA.(*dns.A))
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rr.Header().Name = state.QName()
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m.Answer = append(m.Answer, &rr)
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if e.large {
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for i := 0; i < 29; i++ {
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m.Answer = append(m.Answer, &rr)
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}
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}
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case dns.TypeAAAA:
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rr := *(rrAAAA.(*dns.AAAA))
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rr.Header().Name = state.QName()
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m.Answer = append(m.Answer, &rr)
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case dns.TypeAXFR:
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if drop {
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return 0, nil
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}
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if delay {
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time.Sleep(e.duration)
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}
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xfr(state, trunc)
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return 0, nil
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default:
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if drop {
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return 0, nil
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}
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if delay {
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time.Sleep(e.duration)
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}
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// coredns will return error.
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return dns.RcodeServerFailure, nil
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}
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if drop {
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return 0, nil
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}
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if delay {
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time.Sleep(e.duration)
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}
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state.SizeAndDo(m)
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w.WriteMsg(m)
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return 0, nil
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}
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// Name implements the Handler interface.
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func (e *Erratic) Name() string { return "erratic" }
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var (
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rrA, _ = dns.NewRR(". IN 0 A 192.0.2.53")
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rrAAAA, _ = dns.NewRR(". IN 0 AAAA 2001:DB8::53")
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)
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