1 files changed, 113 insertions, 0 deletions
diff --git a/modules/caddytls/dnssolver.go b/modules/caddytls/dnssolver.go
new file mode 100644
index 0000000..c8a9c3a
--- /dev/null
+++ b/modules/caddytls/dnssolver.go
@@ -0,0 +1,113 @@
+// Copyright 2015 Matthew Holt and The Caddy Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package caddytls
+
+import (
+	"context"
+	"fmt"
+	"sync"
+	"time"
+
+	"github.com/go-acme/lego/v3/challenge"
+	"github.com/go-acme/lego/v3/challenge/dns01"
+	"github.com/libdns/libdns"
+)
+
+// TODO: this is borrowed from https://github.com/mholt/acme - once we
+// switch to that acme library, this file will go away
+
+// solver is a type that makes libdns providers usable as ACME challenge solvers.
+type solver struct {
+	recordManager
+
+	TTL time.Duration
+
+	txtRecords   map[string]libdns.Record // keyed by challenge token
+	txtRecordsMu sync.Mutex
+}
+
+func (s *solver) Present(domain, token, keyAuth string) error {
+	fqdn, value := dns01.GetRecord(domain, keyAuth)
+
+	rec := libdns.Record{
+		Type:  "TXT",
+		Name:  fqdn,
+		Value: value,
+		TTL:   s.TTL,
+	}
+
+	zone, err := dns01.FindZoneByFqdn(fqdn)
+	if err != nil {
+		return fmt.Errorf("could not determine zone for domain %q: %v", fqdn, err)
+	}
+
+	results, err := s.recordManager.AppendRecords(context.TODO(), zone, []libdns.Record{rec})
+	if err != nil {
+		return err
+	}
+	if len(results) != 1 {
+		return fmt.Errorf("expected one record, got %d: %v", len(results), results)
+	}
+
+	// keep this record handy so we can clean it up more efficiently
+	s.txtRecordsMu.Lock()
+	if s.txtRecords == nil {
+		s.txtRecords = make(map[string]libdns.Record)
+	}
+	s.txtRecords[keyAuth] = results[0]
+	s.txtRecordsMu.Unlock()
+
+	// TODO: check for record propagation before continuing (accordig to config)
+
+	return nil
+}
+
+func (s *solver) CleanUp(domain, token, keyAuth string) error {
+	fqdn, _ := dns01.GetRecord(domain, keyAuth)
+	authZone, err := dns01.FindZoneByFqdn(fqdn)
+	if err != nil {
+		return err
+	}
+
+	// retrieve the record we created
+	s.txtRecordsMu.Lock()
+	txtRec, ok := s.txtRecords[keyAuth]
+	if !ok {
+		s.txtRecordsMu.Unlock()
+		return fmt.Errorf("no memory of presenting a DNS record for %v", domain)
+	}
+	s.txtRecordsMu.Unlock()
+
+	// clean up the record
+	_, err = s.recordManager.DeleteRecords(context.TODO(), authZone, []libdns.Record{txtRec})
+	if err != nil {
+		return err
+	}
+
+	// once it has been successfully cleaned up, we can forget about it
+	s.txtRecordsMu.Lock()
+	delete(s.txtRecords, keyAuth)
+	s.txtRecordsMu.Unlock()
+
+	return nil
+}
+
+// recordManager defines the set of operations required for ACME challenges.
+type recordManager interface {
+	libdns.RecordAppender
+	libdns.RecordDeleter
+}
+
+var _ challenge.Provider = (*solver)(nil)