97 lines
2.3 KiB
Go
97 lines
2.3 KiB
Go
package dnstap
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import (
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"context"
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"time"
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"github.com/coredns/coredns/plugin"
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"github.com/coredns/coredns/plugin/dnstap/taprw"
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tap "github.com/dnstap/golang-dnstap"
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"github.com/miekg/dns"
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)
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// Dnstap is the dnstap handler.
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type Dnstap struct {
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Next plugin.Handler
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IO IORoutine
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// Set to true to include the relevant raw DNS message into the dnstap messages.
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JoinRawMessage bool
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}
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type (
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// IORoutine is the dnstap I/O thread as defined by: <http://dnstap.info/Architecture>.
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IORoutine interface {
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Dnstap(tap.Dnstap)
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}
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// Tapper is implemented by the Context passed by the dnstap handler.
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Tapper interface {
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TapMessage(message *tap.Message)
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Pack() bool
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}
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tapContext struct {
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context.Context
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Dnstap
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}
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)
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// ContextKey defines the type of key that is used to save data into the context
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type ContextKey string
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const (
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// DnstapSendOption specifies the Dnstap message to be send. Default is sent all.
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DnstapSendOption ContextKey = "dnstap-send-option"
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)
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// TapperFromContext will return a Tapper if the dnstap plugin is enabled.
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func TapperFromContext(ctx context.Context) (t Tapper) {
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t, _ = ctx.(Tapper)
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return
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}
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// TapMessage implements Tapper.
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func (h *Dnstap) TapMessage(m *tap.Message) {
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t := tap.Dnstap_MESSAGE
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h.IO.Dnstap(tap.Dnstap{
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Type: &t,
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Message: m,
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})
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}
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// Pack returns true if the raw DNS message should be included into the dnstap messages.
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func (h Dnstap) Pack() bool {
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return h.JoinRawMessage
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}
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// ServeDNS logs the client query and response to dnstap and passes the dnstap Context.
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func (h Dnstap) ServeDNS(ctx context.Context, w dns.ResponseWriter, r *dns.Msg) (int, error) {
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// Add send option into context so other plugin can decide on which DNSTap
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// message to be sent out
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sendOption := taprw.SendOption{Cq: true, Cr: true}
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newCtx := context.WithValue(ctx, DnstapSendOption, &sendOption)
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rw := &taprw.ResponseWriter{
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ResponseWriter: w,
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Tapper: &h,
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Query: r,
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Send: &sendOption,
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QueryEpoch: time.Now(),
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}
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code, err := plugin.NextOrFailure(h.Name(), h.Next, tapContext{newCtx, h}, rw, r)
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if err != nil {
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// ignore dnstap errors
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return code, err
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}
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if err = rw.DnstapError(); err != nil {
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return code, plugin.Error("dnstap", err)
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}
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return code, nil
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}
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// Name returns dnstap.
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func (h Dnstap) Name() string { return "dnstap" }
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