You cannot select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
116 lines
2.4 KiB
Go
116 lines
2.4 KiB
Go
/*
|
|
Copyright 2017 The KUAR 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 dnsapi
|
|
|
|
import (
|
|
"encoding/json"
|
|
"fmt"
|
|
"net/http"
|
|
"strings"
|
|
|
|
"github.com/julienschmidt/httprouter"
|
|
"github.com/kubernetes-up-and-running/kuard/pkg/apiutils"
|
|
"github.com/miekg/dns"
|
|
)
|
|
|
|
type DNSAPI struct {
|
|
}
|
|
|
|
// DNSResponse is returned from a GET to this API endpoing
|
|
type DNSResponse struct {
|
|
Results string `json:"result"`
|
|
}
|
|
|
|
type DNSRequest struct {
|
|
Type string `json:"type"`
|
|
Name string `json:"name"`
|
|
}
|
|
|
|
func New() *DNSAPI {
|
|
return &DNSAPI{}
|
|
}
|
|
|
|
func (e *DNSAPI) AddRoutes(r *httprouter.Router, base string) {
|
|
r.POST(base+"/api", e.APIGet)
|
|
}
|
|
|
|
func (e *DNSAPI) APIGet(w http.ResponseWriter, r *http.Request, _ httprouter.Params) {
|
|
dreq := &DNSRequest{}
|
|
|
|
err := json.NewDecoder(r.Body).Decode(dreq)
|
|
if err != nil {
|
|
http.Error(w, err.Error(), http.StatusBadRequest)
|
|
return
|
|
}
|
|
|
|
result, err := dnsQuery(dreq.Type, dreq.Name)
|
|
if err != nil {
|
|
http.Error(w, err.Error(), http.StatusBadRequest)
|
|
return
|
|
}
|
|
|
|
dresp := &DNSResponse{
|
|
Results: result,
|
|
}
|
|
|
|
apiutils.ServeJSON(w, dresp)
|
|
}
|
|
|
|
func dnsQuery(t string, name string) (string, error) {
|
|
config, err := dns.ClientConfigFromFile("/etc/resolv.conf")
|
|
if err != nil {
|
|
return "", err
|
|
}
|
|
|
|
c := new(dns.Client)
|
|
m := new(dns.Msg)
|
|
|
|
qtype, ok := dns.StringToType[strings.ToUpper(t)]
|
|
if !ok {
|
|
return "", fmt.Errorf("Unknown DNS type: %v", t)
|
|
}
|
|
|
|
if len(name) == 0 {
|
|
name = "."
|
|
}
|
|
|
|
names := []string{}
|
|
if dns.IsFqdn(name) {
|
|
names = append(names, name)
|
|
} else {
|
|
// TODO: respect NDOTS
|
|
for _, s := range config.Search {
|
|
names = append(names, name+"."+s)
|
|
}
|
|
names = append(names, name)
|
|
}
|
|
|
|
var r *dns.Msg
|
|
for _, name := range names {
|
|
m.SetQuestion(dns.Fqdn(name), qtype)
|
|
m.RecursionDesired = true
|
|
r, _, err = c.Exchange(m, config.Servers[0]+":"+config.Port)
|
|
if err != nil {
|
|
return "", err
|
|
}
|
|
if len(r.Answer) > 0 {
|
|
return r.String(), nil
|
|
}
|
|
}
|
|
return r.String(), nil
|
|
}
|