136 lines
3.1 KiB
Go
136 lines
3.1 KiB
Go
// Copyright 2009 The Go Authors. All rights reserved.
|
|
// Use of this source code is governed by a BSD-style
|
|
// license that can be found in the LICENSE file.
|
|
// Extended and bugfixes by Miek Gieben
|
|
|
|
// Package dns implements a full featured interface to the DNS.
|
|
// The package allows full control over what is send out to the DNS.
|
|
//
|
|
// Resource Records are types in Go. They are not stored in wire format.
|
|
// Basic usage pattern for creating new Resource Record:
|
|
//
|
|
// r := new(RR_TXT)
|
|
// r.Hdr = RR_Header{Name: "a.miek.nl", Rrtype: TypeTXT, Class: ClassINET, Ttl: 3600}
|
|
// r.TXT = "This is the content of the TXT record"
|
|
//
|
|
// Convert from - Unpack() - and to - Pack() - wire format for
|
|
// Msgs or Resource Records.
|
|
package dns
|
|
|
|
import (
|
|
"strconv"
|
|
)
|
|
|
|
// For RFC1982 (Serial Arithmetic) calculations in 32 bits.
|
|
const Year68 = 2 << (32 - 1)
|
|
|
|
// Error represents a DNS error
|
|
type Error struct {
|
|
Error string
|
|
Name string
|
|
Server string
|
|
Timeout bool
|
|
}
|
|
|
|
func (e *Error) String() string {
|
|
if e == nil {
|
|
return "<nil>"
|
|
}
|
|
return e.Error
|
|
}
|
|
|
|
// Meta data for queries
|
|
type Meta struct {
|
|
QLen int // query length in bytes
|
|
RLen int // reply length in bytes
|
|
QueryStart int64 // start of query in nanoseconds epoch
|
|
QueryEnd int64 // end of query in nanosecond epoch
|
|
}
|
|
|
|
func (m *Meta) String() string {
|
|
s := ";; Query time: " + strconv.Itoa(int(m.QueryEnd-m.QueryStart)) + " nsec"
|
|
s += "\n;; MSG SIZE rcvd: " + strconv.Itoa(m.RLen) + ", sent: " + strconv.Itoa(m.QLen)
|
|
rf := float32(m.RLen)
|
|
qf := float32(m.QLen)
|
|
if qf != 0 {
|
|
s += " (" + strconv.Ftoa32(rf/qf, 'f', 2) + ":1)"
|
|
}
|
|
// WHEN??
|
|
return s
|
|
}
|
|
|
|
type RR interface {
|
|
Header() *RR_Header
|
|
String() string
|
|
}
|
|
|
|
// An RRset is a slice of RRs.
|
|
type RRset []RR
|
|
|
|
func (r RRset) Len() int { return len(r) }
|
|
func (r RRset) Less(i, j int) bool { return r[i].Header().Name < r[j].Header().Name }
|
|
func (r RRset) Swap(i, j int) { r[i], r[j] = r[j], r[i] }
|
|
|
|
// Check if the RRset is RFC 2181 compliant
|
|
func (r RRset) Ok() bool {
|
|
ttl := r[0].Header().Ttl
|
|
name := r[0].Header().Name
|
|
class := r[0].Header().Class
|
|
for _, rr := range r[1:] {
|
|
if rr.Header().Ttl != ttl {
|
|
return false
|
|
}
|
|
if rr.Header().Name != name {
|
|
return false
|
|
}
|
|
if rr.Header().Class != class {
|
|
return false
|
|
}
|
|
}
|
|
return true
|
|
}
|
|
|
|
// DNS resource records.
|
|
// There are many types of messages,
|
|
// but they all share the same header.
|
|
type RR_Header struct {
|
|
Name string "domain-name"
|
|
Rrtype uint16
|
|
Class uint16
|
|
Ttl uint32
|
|
Rdlength uint16 // length of data after header
|
|
}
|
|
|
|
func (h *RR_Header) Header() *RR_Header {
|
|
return h
|
|
}
|
|
|
|
func (h *RR_Header) String() string {
|
|
var s string
|
|
|
|
if h.Rrtype == TypeOPT {
|
|
s = ";"
|
|
// and maybe other things
|
|
}
|
|
|
|
if len(h.Name) == 0 {
|
|
s += ".\t"
|
|
} else {
|
|
s += h.Name + "\t"
|
|
}
|
|
s = s + strconv.Itoa(int(h.Ttl)) + "\t"
|
|
s = s + Class_str[h.Class] + "\t"
|
|
s = s + Rr_str[h.Rrtype] + "\t"
|
|
return s
|
|
}
|
|
|
|
// Return the number of labels in a domain name
|
|
func LabelCount(a string) (c uint8) {
|
|
for _, v := range a {
|
|
if v == '.' {
|
|
c++
|
|
}
|
|
}
|
|
return
|
|
}
|