coredns/plugin/dnssec/handler.go
Miek Gieben ba1efee4f1
Default to scrubbing replies in the server (#2012)
Every plugin needs to deal with EDNS0 and should call Scrub to make a
message fit the client's buffer. Move this functionality into the server
and wrapping the ResponseWriter into a ScrubWriter that handles these
bits for us. Result:

Less code and faster, because multiple chained plugins could all be
calling scrub and SizeAndDo - now there is just one place.

Most tests in file/* and dnssec/* needed adjusting because in those unit
tests you don't see OPT RRs anymore. The DNSSEC signer was also looking
at the returned OPT RR to see if it needed to sign - as those are now
added by the server (and thus later), this needed to change slightly.

Scrub itself still exist (for backward compat reasons), but has been
made a noop. Scrub has been renamed to scrub as it should not be used by
external plugins.

Fixes: #2010

Signed-off-by: Miek Gieben <miek@miek.nl>
2018-08-29 12:26:22 +01:00

85 lines
2.2 KiB
Go

package dnssec
import (
"context"
"sync"
"github.com/coredns/coredns/plugin"
"github.com/coredns/coredns/plugin/metrics"
"github.com/coredns/coredns/request"
"github.com/miekg/dns"
"github.com/prometheus/client_golang/prometheus"
)
// ServeDNS implements the plugin.Handler interface.
func (d Dnssec) ServeDNS(ctx context.Context, w dns.ResponseWriter, r *dns.Msg) (int, error) {
state := request.Request{W: w, Req: r}
do := state.Do()
qname := state.Name()
qtype := state.QType()
zone := plugin.Zones(d.zones).Matches(qname)
if zone == "" {
return plugin.NextOrFailure(d.Name(), d.Next, ctx, w, r)
}
state.Zone = zone
server := metrics.WithServer(ctx)
// Intercept queries for DNSKEY, but only if one of the zones matches the qname, otherwise we let
// the query through.
if qtype == dns.TypeDNSKEY {
for _, z := range d.zones {
if qname == z {
resp := d.getDNSKEY(state, z, do, server)
resp.Authoritative = true
state.SizeAndDo(resp)
w.WriteMsg(resp)
return dns.RcodeSuccess, nil
}
}
}
if do {
drr := &ResponseWriter{w, d, server}
return plugin.NextOrFailure(d.Name(), d.Next, ctx, drr, r)
}
return plugin.NextOrFailure(d.Name(), d.Next, ctx, w, r)
}
var (
cacheSize = prometheus.NewGaugeVec(prometheus.GaugeOpts{
Namespace: plugin.Namespace,
Subsystem: "dnssec",
Name: "cache_size",
Help: "The number of elements in the dnssec cache.",
}, []string{"server", "type"})
cacheCapacity = prometheus.NewGaugeVec(prometheus.GaugeOpts{
Namespace: plugin.Namespace,
Subsystem: "dnssec",
Name: "cache_capacity",
Help: "The dnssec cache's capacity.",
}, []string{"server", "type"})
cacheHits = prometheus.NewCounterVec(prometheus.CounterOpts{
Namespace: plugin.Namespace,
Subsystem: "dnssec",
Name: "cache_hits_total",
Help: "The count of cache hits.",
}, []string{"server"})
cacheMisses = prometheus.NewCounterVec(prometheus.CounterOpts{
Namespace: plugin.Namespace,
Subsystem: "dnssec",
Name: "cache_misses_total",
Help: "The count of cache misses.",
}, []string{"server"})
)
// Name implements the Handler interface.
func (d Dnssec) Name() string { return "dnssec" }
var once sync.Once