forked from coredns/coredns
/
recorder.go
57 lines (50 loc) · 1.56 KB
/
recorder.go
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package dnsrecorder
import (
"time"
"github.com/miekg/dns"
)
// Recorder is a type of ResponseWriter that captures
// the rcode code written to it and also the size of the message
// written in the response. A rcode code does not have
// to be written, however, in which case 0 must be assumed.
// It is best to have the constructor initialize this type
// with that default status code.
type Recorder struct {
dns.ResponseWriter
Rcode int
Size int
Msg *dns.Msg
Start time.Time
}
// New makes and returns a new Recorder,
// which captures the DNS rcode from the ResponseWriter
// and also the length of the response message written through it.
func New(w dns.ResponseWriter) *Recorder {
return &Recorder{
ResponseWriter: w,
Rcode: 0,
Msg: nil,
Start: time.Now(),
}
}
// WriteMsg records the status code and calls the
// underlying ResponseWriter's WriteMsg method.
func (r *Recorder) WriteMsg(res *dns.Msg) error {
r.Rcode = res.Rcode
// We may get called multiple times (axfr for instance).
// Save the last message, but add the sizes.
r.Size += res.Len()
r.Msg = res
return r.ResponseWriter.WriteMsg(res)
}
// Write is a wrapper that records the size of the message that gets written.
func (r *Recorder) Write(buf []byte) (int, error) {
n, err := r.ResponseWriter.Write(buf)
if err == nil {
r.Size += n
}
return n, err
}
// Hijack implements dns.Hijacker. It simply wraps the underlying
// ResponseWriter's Hijack method if there is one, or returns an error.
func (r *Recorder) Hijack() { r.ResponseWriter.Hijack(); return }