Files
cgrates/agents/libdns.go

118 lines
3.3 KiB
Go

/*
Real-time Online/Offline Charging System (OCS) for Telecom & ISP environments
Copyright (C) ITsysCOM GmbH
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>
*/
package agents
import (
"errors"
"fmt"
"net"
"strings"
"github.com/cgrates/cgrates/config"
"github.com/cgrates/cgrates/utils"
"github.com/miekg/dns"
)
const (
QueryType = "QueryType"
E164Address = "E164"
)
// e164FromNAPTR extracts the E164 address out of a NAPTR name record
func e164FromNAPTR(name string) (e164 string, err error) {
i := strings.Index(name, ".e164.arpa")
if i == -1 {
return "", errors.New("unknown format")
}
e164 = utils.ReverseString(
strings.Replace(name[:i], ".", "", -1))
return
}
// newDADataProvider constructs a DataProvider for a diameter message
func newDNSDataProvider(req *dns.Msg,
w dns.ResponseWriter) config.DataProvider {
return &dnsDP{req: req, w: w,
cache: config.NewNavigableMap(nil)}
}
// dnsDP implements engien.DataProvider, serving as dns.Msg decoder
// cache is used to cache queries within the message
type dnsDP struct {
req *dns.Msg
w dns.ResponseWriter
cache *config.NavigableMap
}
// String is part of engine.DataProvider interface
// when called, it will display the already parsed values out of cache
func (dP *dnsDP) String() string {
return utils.ToJSON(dP.req)
}
// AsNavigableMap is part of engine.DataProvider interface
func (dP *dnsDP) AsNavigableMap([]*config.FCTemplate) (
nm *config.NavigableMap, err error) {
return nil, utils.ErrNotImplemented
}
// FieldAsString is part of engine.DataProvider interface
func (dP *dnsDP) FieldAsString(fldPath []string) (data string, err error) {
var valIface interface{}
valIface, err = dP.FieldAsInterface(fldPath)
if err != nil {
return
}
return utils.IfaceAsString(valIface)
}
// RemoteHost is part of engine.DataProvider interface
func (dP *dnsDP) RemoteHost() net.Addr {
return utils.NewNetAddr(dP.w.RemoteAddr().Network(), dP.w.RemoteAddr().String())
}
// FieldAsInterface is part of engine.DataProvider interface
func (dP *dnsDP) FieldAsInterface(fldPath []string) (data interface{}, err error) {
if data, err = dP.cache.FieldAsInterface(fldPath); err != nil {
if err != utils.ErrNotFound { // item found in cache
return nil, err
}
err = nil // cancel previous err
} else {
return // data was found in cache
}
data = ""
// Return Question[0] by default
if len(dP.req.Question) != 0 {
data = dP.req.Question[0]
}
dP.cache.Set(fldPath, data, false, false)
return
}
// dnsWriteErr writes the error with code back to the client
func dnsWriteMsg(w dns.ResponseWriter, msg *dns.Msg) (err error) {
if err = w.WriteMsg(msg); err != nil {
utils.Logger.Warning(
fmt.Sprintf("<%s> error: <%s> when writing on connection",
utils.DNSAgent, err.Error()))
}
return
}