85 lines
2.4 KiB
Go
85 lines
2.4 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/msg"
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"github.com/coredns/coredns/plugin/pkg/replacer"
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"github.com/coredns/coredns/request"
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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 tapper
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repl replacer.Replacer
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// IncludeRawMessage will include the raw DNS message into the dnstap messages if true.
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IncludeRawMessage bool
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Identity []byte
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Version []byte
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ExtraFormat string
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}
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// TapMessage sends the message m to the dnstap interface, without populating "Extra" field.
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func (h *Dnstap) TapMessage(m *tap.Message) {
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if h.ExtraFormat == "" {
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h.tapWithExtra(m, nil)
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} else {
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h.tapWithExtra(m, []byte(h.ExtraFormat))
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}
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}
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// TapMessageWithMetadata sends the message m to the dnstap interface, with "Extra" field being populated.
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func (h *Dnstap) TapMessageWithMetadata(ctx context.Context, m *tap.Message, state request.Request) {
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if h.ExtraFormat == "" {
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h.tapWithExtra(m, nil)
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return
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}
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extraStr := h.repl.Replace(ctx, state, nil, h.ExtraFormat)
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h.tapWithExtra(m, []byte(extraStr))
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}
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func (h *Dnstap) tapWithExtra(m *tap.Message, extra []byte) {
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t := tap.Dnstap_MESSAGE
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h.io.Dnstap(&tap.Dnstap{Type: &t, Message: m, Identity: h.Identity, Version: h.Version, Extra: extra})
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}
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func (h *Dnstap) tapQuery(ctx context.Context, w dns.ResponseWriter, query *dns.Msg, queryTime time.Time) {
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q := new(tap.Message)
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msg.SetQueryTime(q, queryTime)
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msg.SetQueryAddress(q, w.RemoteAddr())
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if h.IncludeRawMessage {
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buf, _ := query.Pack()
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q.QueryMessage = buf
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}
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msg.SetType(q, tap.Message_CLIENT_QUERY)
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state := request.Request{W: w, Req: query}
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h.TapMessageWithMetadata(ctx, q, state)
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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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rw := &ResponseWriter{
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ResponseWriter: w,
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Dnstap: h,
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query: r,
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ctx: ctx,
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queryTime: time.Now(),
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}
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// The query tap message should be sent before sending the query to the
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// forwarder. Otherwise, the tap messages will come out out of order.
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h.tapQuery(ctx, w, r, rw.queryTime)
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return plugin.NextOrFailure(h.Name(), h.Next, ctx, rw, r)
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}
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// Name implements the plugin.Plugin interface.
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func (h *Dnstap) Name() string { return "dnstap" }
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