mirror of
https://github.com/coredns/coredns.git
synced 2026-10-09 03:55:21 -04:00
b0b317fdd6
When the plugin chain returns an error rcode without writing a response (it falls off the end, or returns SERVFAIL/REFUSED/FORMERR/NOTIMP), the server generates and sends the error to the client after dnstap's ServeDNS returns, so ResponseWriter.WriteMsg is never called and no CLIENT_RESPONSE dnstap message is emitted. dnstap consumers then see a CLIENT_QUERY with no matching CLIENT_RESPONSE. Synthesize the deferred response and tap it as a CLIENT_RESPONSE, mirroring the deferred-response handling already added to plugin/log. Fixes #6532 Signed-off-by: Saleh <root@lr0.org>
114 lines
3.4 KiB
Go
114 lines
3.4 KiB
Go
package dnstap
|
|
|
|
import (
|
|
"context"
|
|
"time"
|
|
|
|
"github.com/coredns/coredns/plugin"
|
|
"github.com/coredns/coredns/plugin/dnstap/msg"
|
|
"github.com/coredns/coredns/plugin/pkg/replacer"
|
|
"github.com/coredns/coredns/request"
|
|
|
|
tap "github.com/dnstap/golang-dnstap"
|
|
"github.com/miekg/dns"
|
|
)
|
|
|
|
// Dnstap is the dnstap handler.
|
|
type Dnstap struct {
|
|
Next plugin.Handler
|
|
io tapper
|
|
listener *listener
|
|
repl replacer.Replacer
|
|
|
|
// IncludeRawMessage will include the raw DNS message into the dnstap messages if true.
|
|
IncludeRawMessage bool
|
|
Identity []byte
|
|
Version []byte
|
|
ExtraFormat string
|
|
MultipleTcpWriteBuf int // *Mb
|
|
MultipleQueue int // *10000
|
|
}
|
|
|
|
// TapMessage sends the message m to the dnstap interface, without populating "Extra" field.
|
|
func (h *Dnstap) TapMessage(m *tap.Message) {
|
|
if h.ExtraFormat == "" {
|
|
h.tapWithExtra(m, nil)
|
|
} else {
|
|
h.tapWithExtra(m, []byte(h.ExtraFormat))
|
|
}
|
|
}
|
|
|
|
// TapMessageWithMetadata sends the message m to the dnstap interface, with "Extra" field being populated.
|
|
func (h *Dnstap) TapMessageWithMetadata(ctx context.Context, m *tap.Message, state request.Request) {
|
|
if h.ExtraFormat == "" {
|
|
h.tapWithExtra(m, nil)
|
|
return
|
|
}
|
|
extraStr := h.repl.Replace(ctx, state, nil, h.ExtraFormat)
|
|
h.tapWithExtra(m, []byte(extraStr))
|
|
}
|
|
|
|
func (h *Dnstap) tapWithExtra(m *tap.Message, extra []byte) {
|
|
t := tap.Dnstap_MESSAGE
|
|
payload := &tap.Dnstap{Type: &t, Message: m, Identity: h.Identity, Version: h.Version, Extra: extra}
|
|
|
|
// Send to outgoing connection if configured
|
|
if h.io != nil {
|
|
h.io.Dnstap(payload)
|
|
}
|
|
|
|
// Broadcast to incoming listeners if configured
|
|
if h.listener != nil {
|
|
h.listener.Dnstap(payload)
|
|
}
|
|
}
|
|
|
|
func (h *Dnstap) tapQuery(ctx context.Context, w dns.ResponseWriter, query *dns.Msg, queryTime time.Time) {
|
|
q := new(tap.Message)
|
|
msg.SetQueryTime(q, queryTime)
|
|
msg.SetQueryAddress(q, w.RemoteAddr())
|
|
|
|
if h.IncludeRawMessage {
|
|
buf, _ := query.Pack()
|
|
q.QueryMessage = buf
|
|
}
|
|
msg.SetType(q, tap.Message_CLIENT_QUERY)
|
|
state := request.Request{W: w, Req: query}
|
|
h.TapMessageWithMetadata(ctx, q, state)
|
|
}
|
|
|
|
// ServeDNS logs the client query and response to dnstap and passes the dnstap Context.
|
|
func (h *Dnstap) ServeDNS(ctx context.Context, w dns.ResponseWriter, r *dns.Msg) (int, error) {
|
|
rw := &ResponseWriter{
|
|
ResponseWriter: w,
|
|
Dnstap: h,
|
|
query: r,
|
|
ctx: ctx,
|
|
queryTime: time.Now(),
|
|
}
|
|
|
|
// The query tap message should be sent before sending the query to the
|
|
// forwarder. Otherwise, the tap messages will come out out of order.
|
|
h.tapQuery(ctx, w, r, rw.queryTime)
|
|
|
|
rcode, err := plugin.NextOrFailure(h.Name(), h.Next, ctx, rw, r)
|
|
|
|
// When the plugin chain returns an error rcode without having written a
|
|
// response (e.g. it falls off the end, or returns SERVFAIL/REFUSED/FORMERR/
|
|
// NOTIMP), the server generates and sends the error response to the client
|
|
// after ServeDNS returns, so ResponseWriter.WriteMsg is never called and no
|
|
// CLIENT_RESPONSE is tapped. Synthesize the deferred response so dnstap
|
|
// consumers see a CLIENT_RESPONSE matching what the client receives, rather
|
|
// than a CLIENT_QUERY with no matching response (#6532).
|
|
if !rw.written && !plugin.ClientWrite(rcode) {
|
|
deferred := new(dns.Msg)
|
|
deferred.SetRcode(r, rcode)
|
|
rw.tapResponse(deferred)
|
|
}
|
|
|
|
return rcode, err
|
|
}
|
|
|
|
// Name implements the plugin.Plugin interface.
|
|
func (h *Dnstap) Name() string { return "dnstap" }
|