106 lines
2.5 KiB
Go
106 lines
2.5 KiB
Go
package file
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import "github.com/miekg/dns"
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// Result is the result of a Lookup
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type Result int
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const (
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Success Result = iota
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NameError
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NoData // aint no offical NoData return code.
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)
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// Lookup looks up qname and qtype in the zone, when do is true DNSSEC are included as well.
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// Two sets of records are returned, one for the answer and one for the additional section.
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func (z *Zone) Lookup(qname string, qtype uint16, do bool) ([]dns.RR, []dns.RR, Result) {
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var rr dns.RR
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mk, known := dns.TypeToRR[qtype]
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if !known {
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an, ad, _ := z.lookupSOA(do)
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return an, ad, NameError
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// Uhm...? rr = new(RFC3597) ??
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} else {
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rr = mk()
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}
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rr.Header().Rrtype = qtype // this is pretty nonobvious
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if qtype == dns.TypeSOA {
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return z.lookupSOA(do)
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}
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rr.Header().Name = qname
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elem := z.Tree.Get(rr)
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if elem == nil {
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an, ad, _ := z.lookupSOA(do)
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return an, ad, NameError
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}
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rrs := elem.Types(dns.TypeCNAME)
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if len(rrs) > 0 { // should only ever be 1 actually; TODO(miek) check for this?
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rr.Header().Name = rrs[0].(*dns.CNAME).Target
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return z.lookupCNAME(rrs, rr, do)
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}
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rrs = elem.Types(qtype)
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if len(rrs) == 0 {
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an, ad, _ := z.lookupSOA(do)
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return an, ad, NoData
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}
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if do {
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sigs := elem.Types(dns.TypeRRSIG)
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sigs = signatureForSubType(sigs, qtype)
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if len(sigs) > 0 {
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rrs = append(rrs, sigs...)
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}
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}
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return rrs, nil, Success
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}
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func (z *Zone) lookupSOA(do bool) ([]dns.RR, []dns.RR, Result) {
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if do {
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ret := append([]dns.RR{z.SOA}, z.SIG...)
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return ret, nil, Success
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}
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return []dns.RR{z.SOA}, nil, Success
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}
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func (z *Zone) lookupCNAME(rrs []dns.RR, rr dns.RR, do bool) ([]dns.RR, []dns.RR, Result) {
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elem := z.Tree.Get(rr)
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if elem == nil {
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return rrs, nil, Success
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}
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extra := cnameForType(elem.All(), rr.Header().Rrtype)
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if do {
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sigs := elem.Types(dns.TypeRRSIG)
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sigs = signatureForSubType(sigs, rr.Header().Rrtype)
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if len(sigs) > 0 {
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extra = append(extra, sigs...)
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}
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}
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return rrs, extra, Success
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}
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func cnameForType(targets []dns.RR, origQtype uint16) []dns.RR {
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ret := []dns.RR{}
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for _, target := range targets {
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if target.Header().Rrtype == origQtype {
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ret = append(ret, target)
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}
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}
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return ret
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}
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// signatureForSubType range through the signature and return the correct
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// ones for the subtype.
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func signatureForSubType(rrs []dns.RR, subtype uint16) []dns.RR {
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sigs := []dns.RR{}
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for _, sig := range rrs {
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if s, ok := sig.(*dns.RRSIG); ok {
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if s.TypeCovered == subtype {
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sigs = append(sigs, s)
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}
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}
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}
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return sigs
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}
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