a685e3fc98
Vndr has a simpler configuration and allows pointing to forked packages. Additionally other docker projects are now using vndr making vendoring in distribution more consistent. Updates letsencrypt to use fork. No longer uses sub-vendored packages. Signed-off-by: Derek McGowan <derek@mcgstyle.net> (github: dmcgowan)
282 lines
8 KiB
Go
282 lines
8 KiB
Go
package dns
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import (
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"errors"
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"net"
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"strconv"
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)
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const hexDigit = "0123456789abcdef"
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// Everything is assumed in ClassINET.
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// SetReply creates a reply message from a request message.
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func (dns *Msg) SetReply(request *Msg) *Msg {
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dns.Id = request.Id
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dns.RecursionDesired = request.RecursionDesired // Copy rd bit
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dns.Response = true
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dns.Opcode = OpcodeQuery
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dns.Rcode = RcodeSuccess
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if len(request.Question) > 0 {
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dns.Question = make([]Question, 1)
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dns.Question[0] = request.Question[0]
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}
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return dns
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}
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// SetQuestion creates a question message, it sets the Question
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// section, generates an Id and sets the RecursionDesired (RD)
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// bit to true.
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func (dns *Msg) SetQuestion(z string, t uint16) *Msg {
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dns.Id = Id()
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dns.RecursionDesired = true
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dns.Question = make([]Question, 1)
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dns.Question[0] = Question{z, t, ClassINET}
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return dns
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}
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// SetNotify creates a notify message, it sets the Question
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// section, generates an Id and sets the Authoritative (AA)
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// bit to true.
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func (dns *Msg) SetNotify(z string) *Msg {
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dns.Opcode = OpcodeNotify
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dns.Authoritative = true
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dns.Id = Id()
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dns.Question = make([]Question, 1)
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dns.Question[0] = Question{z, TypeSOA, ClassINET}
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return dns
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}
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// SetRcode creates an error message suitable for the request.
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func (dns *Msg) SetRcode(request *Msg, rcode int) *Msg {
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dns.SetReply(request)
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dns.Rcode = rcode
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return dns
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}
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// SetRcodeFormatError creates a message with FormError set.
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func (dns *Msg) SetRcodeFormatError(request *Msg) *Msg {
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dns.Rcode = RcodeFormatError
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dns.Opcode = OpcodeQuery
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dns.Response = true
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dns.Authoritative = false
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dns.Id = request.Id
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return dns
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}
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// SetUpdate makes the message a dynamic update message. It
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// sets the ZONE section to: z, TypeSOA, ClassINET.
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func (dns *Msg) SetUpdate(z string) *Msg {
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dns.Id = Id()
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dns.Response = false
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dns.Opcode = OpcodeUpdate
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dns.Compress = false // BIND9 cannot handle compression
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dns.Question = make([]Question, 1)
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dns.Question[0] = Question{z, TypeSOA, ClassINET}
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return dns
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}
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// SetIxfr creates message for requesting an IXFR.
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func (dns *Msg) SetIxfr(z string, serial uint32, ns, mbox string) *Msg {
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dns.Id = Id()
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dns.Question = make([]Question, 1)
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dns.Ns = make([]RR, 1)
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s := new(SOA)
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s.Hdr = RR_Header{z, TypeSOA, ClassINET, defaultTtl, 0}
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s.Serial = serial
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s.Ns = ns
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s.Mbox = mbox
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dns.Question[0] = Question{z, TypeIXFR, ClassINET}
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dns.Ns[0] = s
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return dns
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}
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// SetAxfr creates message for requesting an AXFR.
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func (dns *Msg) SetAxfr(z string) *Msg {
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dns.Id = Id()
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dns.Question = make([]Question, 1)
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dns.Question[0] = Question{z, TypeAXFR, ClassINET}
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return dns
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}
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// SetTsig appends a TSIG RR to the message.
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// This is only a skeleton TSIG RR that is added as the last RR in the
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// additional section. The Tsig is calculated when the message is being send.
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func (dns *Msg) SetTsig(z, algo string, fudge, timesigned int64) *Msg {
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t := new(TSIG)
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t.Hdr = RR_Header{z, TypeTSIG, ClassANY, 0, 0}
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t.Algorithm = algo
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t.Fudge = 300
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t.TimeSigned = uint64(timesigned)
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t.OrigId = dns.Id
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dns.Extra = append(dns.Extra, t)
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return dns
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}
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// SetEdns0 appends a EDNS0 OPT RR to the message.
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// TSIG should always the last RR in a message.
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func (dns *Msg) SetEdns0(udpsize uint16, do bool) *Msg {
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e := new(OPT)
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e.Hdr.Name = "."
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e.Hdr.Rrtype = TypeOPT
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e.SetUDPSize(udpsize)
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if do {
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e.SetDo()
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}
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dns.Extra = append(dns.Extra, e)
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return dns
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}
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// IsTsig checks if the message has a TSIG record as the last record
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// in the additional section. It returns the TSIG record found or nil.
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func (dns *Msg) IsTsig() *TSIG {
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if len(dns.Extra) > 0 {
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if dns.Extra[len(dns.Extra)-1].Header().Rrtype == TypeTSIG {
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return dns.Extra[len(dns.Extra)-1].(*TSIG)
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}
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}
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return nil
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}
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// IsEdns0 checks if the message has a EDNS0 (OPT) record, any EDNS0
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// record in the additional section will do. It returns the OPT record
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// found or nil.
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func (dns *Msg) IsEdns0() *OPT {
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// EDNS0 is at the end of the additional section, start there.
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// We might want to change this to *only* look at the last two
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// records. So we see TSIG and/or OPT - this a slightly bigger
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// change though.
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for i := len(dns.Extra) - 1; i >= 0; i-- {
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if dns.Extra[i].Header().Rrtype == TypeOPT {
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return dns.Extra[i].(*OPT)
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}
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}
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return nil
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}
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// IsDomainName checks if s is a valid domain name, it returns the number of
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// labels and true, when a domain name is valid. Note that non fully qualified
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// domain name is considered valid, in this case the last label is counted in
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// the number of labels. When false is returned the number of labels is not
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// defined. Also note that this function is extremely liberal; almost any
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// string is a valid domain name as the DNS is 8 bit protocol. It checks if each
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// label fits in 63 characters, but there is no length check for the entire
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// string s. I.e. a domain name longer than 255 characters is considered valid.
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func IsDomainName(s string) (labels int, ok bool) {
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_, labels, err := packDomainName(s, nil, 0, nil, false)
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return labels, err == nil
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}
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// IsSubDomain checks if child is indeed a child of the parent. If child and parent
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// are the same domain true is returned as well.
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func IsSubDomain(parent, child string) bool {
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// Entire child is contained in parent
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return CompareDomainName(parent, child) == CountLabel(parent)
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}
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// IsMsg sanity checks buf and returns an error if it isn't a valid DNS packet.
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// The checking is performed on the binary payload.
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func IsMsg(buf []byte) error {
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// Header
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if len(buf) < 12 {
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return errors.New("dns: bad message header")
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}
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// Header: Opcode
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// TODO(miek): more checks here, e.g. check all header bits.
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return nil
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}
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// IsFqdn checks if a domain name is fully qualified.
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func IsFqdn(s string) bool {
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l := len(s)
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if l == 0 {
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return false
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}
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return s[l-1] == '.'
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}
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// IsRRset checks if a set of RRs is a valid RRset as defined by RFC 2181.
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// This means the RRs need to have the same type, name, and class. Returns true
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// if the RR set is valid, otherwise false.
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func IsRRset(rrset []RR) bool {
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if len(rrset) == 0 {
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return false
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}
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if len(rrset) == 1 {
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return true
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}
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rrHeader := rrset[0].Header()
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rrType := rrHeader.Rrtype
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rrClass := rrHeader.Class
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rrName := rrHeader.Name
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for _, rr := range rrset[1:] {
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curRRHeader := rr.Header()
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if curRRHeader.Rrtype != rrType || curRRHeader.Class != rrClass || curRRHeader.Name != rrName {
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// Mismatch between the records, so this is not a valid rrset for
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//signing/verifying
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return false
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}
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}
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return true
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}
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// Fqdn return the fully qualified domain name from s.
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// If s is already fully qualified, it behaves as the identity function.
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func Fqdn(s string) string {
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if IsFqdn(s) {
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return s
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}
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return s + "."
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}
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// Copied from the official Go code.
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// ReverseAddr returns the in-addr.arpa. or ip6.arpa. hostname of the IP
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// address suitable for reverse DNS (PTR) record lookups or an error if it fails
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// to parse the IP address.
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func ReverseAddr(addr string) (arpa string, err error) {
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ip := net.ParseIP(addr)
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if ip == nil {
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return "", &Error{err: "unrecognized address: " + addr}
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}
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if ip.To4() != nil {
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return strconv.Itoa(int(ip[15])) + "." + strconv.Itoa(int(ip[14])) + "." + strconv.Itoa(int(ip[13])) + "." +
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strconv.Itoa(int(ip[12])) + ".in-addr.arpa.", nil
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}
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// Must be IPv6
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buf := make([]byte, 0, len(ip)*4+len("ip6.arpa."))
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// Add it, in reverse, to the buffer
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for i := len(ip) - 1; i >= 0; i-- {
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v := ip[i]
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buf = append(buf, hexDigit[v&0xF])
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buf = append(buf, '.')
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buf = append(buf, hexDigit[v>>4])
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buf = append(buf, '.')
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}
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// Append "ip6.arpa." and return (buf already has the final .)
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buf = append(buf, "ip6.arpa."...)
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return string(buf), nil
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}
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// String returns the string representation for the type t.
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func (t Type) String() string {
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if t1, ok := TypeToString[uint16(t)]; ok {
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return t1
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}
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return "TYPE" + strconv.Itoa(int(t))
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}
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// String returns the string representation for the class c.
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func (c Class) String() string {
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if c1, ok := ClassToString[uint16(c)]; ok {
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return c1
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}
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return "CLASS" + strconv.Itoa(int(c))
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}
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// String returns the string representation for the name n.
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func (n Name) String() string {
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return sprintName(string(n))
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}
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