123 lines
2.6 KiB
Go
123 lines
2.6 KiB
Go
// Copyright 2009 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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// Extended and bugfixes by Miek Gieben
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// Supported RFCs and features include:
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// * 1034/1035 - DNS standard
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// * 1982 - Serial Arithmetic
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// * 1876 - LOC record (incomplete)
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// * 1995 - IXFR
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// * 1996 - DNS notify
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// * 2181 - RRset definition
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// * 2537 - RSAMD5 DNS keys
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// * 2065 - DNSSEC (updated in later RFCs)
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// * 2671 - EDNS
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// * 2782 - SRV record
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// * 2845 - TSIG
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// * 2915 - NAPTR record
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// * 3110 - RSASHA1 DNS keys
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// * 3225 - DO bit (DNSSEC OK)
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// * 4033/4034/4035 - DNSSEC + validation functions
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// * 4255 - SSHFP record
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// * 5011 - NSID
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// * 5936 - AXFR
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// * IP6 support
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// Package dns implements a full featured interface to the DNS.
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// The package allows full control over what is send out to the DNS. All RR types are converted
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// to Go types.
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//
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package dns
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import (
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"strconv"
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)
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// For RFC1982 (Serial Arithmetic) calculations.
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const Year68 = 2 << (32 - 1)
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// Error represents a DNS error
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type Error struct {
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Error string
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Name string
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Server string
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Timeout bool
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}
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func (e *Error) String() string {
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if e == nil {
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return "<nil>"
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}
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return e.Error
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}
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type RR interface {
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Header() *RR_Header
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String() string
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}
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// An RRset is a slice of RRs.
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type RRset []RR
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func (r RRset) Len() int { return len(r) }
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func (r RRset) Less(i, j int) bool { return r[i].Header().Name < r[j].Header().Name }
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func (r RRset) Swap(i, j int) { r[i], r[j] = r[j], r[i] }
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// Check if the RRset is RFC 2181 compliant
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func (r RRset) Ok() bool {
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ttl := r[0].Header().Ttl
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name := r[0].Header().Name
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class := r[0].Header().Class
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for _, rr := range r[1:] {
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if rr.Header().Ttl != ttl { return false }
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if rr.Header().Name != name { return false }
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if rr.Header().Class != class { return false }
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}
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return true
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}
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// DNS resource records.
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// There are many types of messages,
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// but they all share the same header.
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type RR_Header struct {
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Name string "domain-name"
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Rrtype uint16
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Class uint16
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Ttl uint32
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Rdlength uint16 // length of data after header
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}
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func (h *RR_Header) Header() *RR_Header {
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return h
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}
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func (h *RR_Header) String() string {
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var s string
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if h.Rrtype == TypeOPT {
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s = ";"
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// and maybe other things
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}
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if len(h.Name) == 0 {
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s += ".\t"
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} else {
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s += h.Name + "\t"
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}
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s = s + strconv.Itoa(int(h.Ttl)) + "\t"
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s = s + Class_str[h.Class] + "\t"
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s = s + Rr_str[h.Rrtype] + "\t"
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return s
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}
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// Return the number of labels in a domain name
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func LabelCount(a string) (c uint8) {
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for _, v := range a {
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if v == '.' {
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c++
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}
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}
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return
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}
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