diff options
Diffstat (limited to 'middleware/file/lookup.go')
| -rw-r--r-- | middleware/file/lookup.go | 467 |
1 files changed, 0 insertions, 467 deletions
diff --git a/middleware/file/lookup.go b/middleware/file/lookup.go deleted file mode 100644 index 89e0f5a47..000000000 --- a/middleware/file/lookup.go +++ /dev/null @@ -1,467 +0,0 @@ -package file - -import ( - "github.com/coredns/coredns/middleware/file/tree" - "github.com/coredns/coredns/request" - - "github.com/miekg/dns" -) - -// Result is the result of a Lookup -type Result int - -const ( - // Success is a successful lookup. - Success Result = iota - // NameError indicates a nameerror - NameError - // Delegation indicates the lookup resulted in a delegation. - Delegation - // NoData indicates the lookup resulted in a NODATA. - NoData - // ServerFailure indicates a server failure during the lookup. - ServerFailure -) - -// Lookup looks up qname and qtype in the zone. When do is true DNSSEC records are included. -// Three sets of records are returned, one for the answer, one for authority and one for the additional section. -func (z *Zone) Lookup(state request.Request, qname string) ([]dns.RR, []dns.RR, []dns.RR, Result) { - - qtype := state.QType() - do := state.Do() - - if !z.NoReload { - z.reloadMu.RLock() - } - defer func() { - if !z.NoReload { - z.reloadMu.RUnlock() - } - }() - - // If z is a secondary zone we might not have transferred it, meaning we have - // all zone context setup, except the actual record. This means (for one thing) the apex - // is empty and we don't have a SOA record. - soa := z.Apex.SOA - if soa == nil { - return nil, nil, nil, ServerFailure - } - - if qtype == dns.TypeSOA { - return z.soa(do), z.ns(do), nil, Success - } - if qtype == dns.TypeNS && qname == z.origin { - nsrrs := z.ns(do) - glue := z.Glue(nsrrs, do) - return nsrrs, nil, glue, Success - } - - var ( - found, shot bool - parts string - i int - elem, wildElem *tree.Elem - ) - - // Lookup: - // * Per label from the right, look if it exists. We do this to find potential - // delegation records. - // * If the per-label search finds nothing, we will look for the wildcard at the - // level. If found we keep it around. If we don't find the complete name we will - // use the wildcard. - // - // Main for-loop handles delegation and finding or not finding the qname. - // If found we check if it is a CNAME/DNAME and do CNAME processing - // We also check if we have type and do a nodata resposne. - // - // If not found, we check the potential wildcard, and use that for further processing. - // If not found and no wildcard we will process this as an NXDOMAIN response. - for { - parts, shot = z.nameFromRight(qname, i) - // We overshot the name, break and check if we previously found something. - if shot { - break - } - - elem, found = z.Tree.Search(parts) - if !found { - // Apex will always be found, when we are here we can search for a wildcard - // and save the result of that search. So when nothing match, but we have a - // wildcard we should expand the wildcard. - - wildcard := replaceWithAsteriskLabel(parts) - if wild, found := z.Tree.Search(wildcard); found { - wildElem = wild - } - - // Keep on searching, because maybe we hit an empty-non-terminal (which aren't - // stored in the tree. Only when we have match the full qname (and possible wildcard - // we can be confident that we didn't find anything. - i++ - continue - } - - // If we see DNAME records, we should return those. - if dnamerrs := elem.Types(dns.TypeDNAME); dnamerrs != nil { - // Only one DNAME is allowed per name. We just pick the first one to synthesize from. - dname := dnamerrs[0] - if cname := synthesizeCNAME(state.Name(), dname.(*dns.DNAME)); cname != nil { - answer, ns, extra, rcode := z.searchCNAME(state, elem, []dns.RR{cname}) - - if do { - sigs := elem.Types(dns.TypeRRSIG) - sigs = signatureForSubType(sigs, dns.TypeDNAME) - dnamerrs = append(dnamerrs, sigs...) - } - - // The relevant DNAME RR should be included in the answer section, - // if the DNAME is being employed as a substitution instruction. - answer = append(dnamerrs, answer...) - - return answer, ns, extra, rcode - } - // The domain name that owns a DNAME record is allowed to have other RR types - // at that domain name, except those have restrictions on what they can coexist - // with (e.g. another DNAME). So there is nothing special left here. - } - - // If we see NS records, it means the name as been delegated, and we should return the delegation. - if nsrrs := elem.Types(dns.TypeNS); nsrrs != nil { - glue := z.Glue(nsrrs, do) - // If qtype == NS, we should returns success to put RRs in answer. - if qtype == dns.TypeNS { - return nsrrs, nil, glue, Success - } - - if do { - dss := z.typeFromElem(elem, dns.TypeDS, do) - nsrrs = append(nsrrs, dss...) - } - - return nil, nsrrs, glue, Delegation - } - - i++ - } - - // What does found and !shot mean - do we ever hit it? - if found && !shot { - return nil, nil, nil, ServerFailure - } - - // Found entire name. - if found && shot { - - if rrs := elem.Types(dns.TypeCNAME); len(rrs) > 0 && qtype != dns.TypeCNAME { - return z.searchCNAME(state, elem, rrs) - } - - rrs := elem.Types(qtype, qname) - - // NODATA - if len(rrs) == 0 { - ret := z.soa(do) - if do { - nsec := z.typeFromElem(elem, dns.TypeNSEC, do) - ret = append(ret, nsec...) - } - return nil, ret, nil, NoData - } - - // Additional section processing for MX, SRV. Check response and see if any of the names are in baliwick - - // if so add IP addresses to the additional section. - additional := additionalProcessing(z, rrs, do) - - if do { - sigs := elem.Types(dns.TypeRRSIG) - sigs = signatureForSubType(sigs, qtype) - rrs = append(rrs, sigs...) - } - - return rrs, z.ns(do), additional, Success - - } - - // Haven't found the original name. - - // Found wildcard. - if wildElem != nil { - auth := z.ns(do) - - if rrs := wildElem.Types(dns.TypeCNAME, qname); len(rrs) > 0 { - return z.searchCNAME(state, wildElem, rrs) - } - - rrs := wildElem.Types(qtype, qname) - - // NODATA response. - if len(rrs) == 0 { - ret := z.soa(do) - if do { - nsec := z.typeFromElem(wildElem, dns.TypeNSEC, do) - ret = append(ret, nsec...) - } - return nil, ret, nil, Success - } - - if do { - // An NSEC is needed to say no longer name exists under this wildcard. - if deny, found := z.Tree.Prev(qname); found { - nsec := z.typeFromElem(deny, dns.TypeNSEC, do) - auth = append(auth, nsec...) - } - - sigs := wildElem.Types(dns.TypeRRSIG, qname) - sigs = signatureForSubType(sigs, qtype) - rrs = append(rrs, sigs...) - - } - return rrs, auth, nil, Success - } - - rcode := NameError - - // Hacky way to get around empty-non-terminals. If a longer name does exist, but this qname, does not, it - // must be an empty-non-terminal. If so, we do the proper NXDOMAIN handling, but set the rcode to be success. - if x, found := z.Tree.Next(qname); found { - if dns.IsSubDomain(qname, x.Name()) { - rcode = Success - } - } - - ret := z.soa(do) - if do { - deny, _ := z.Tree.Prev(qname) // TODO(miek): *found* was not used here. - nsec := z.typeFromElem(deny, dns.TypeNSEC, do) - ret = append(ret, nsec...) - - if rcode != NameError { - goto Out - } - - ce, found := z.ClosestEncloser(qname) - - // wildcard denial only for NXDOMAIN - if found { - // wildcard denial - wildcard := "*." + ce.Name() - if ss, found := z.Tree.Prev(wildcard); found { - // Only add this nsec if it is different than the one already added - if ss.Name() != deny.Name() { - nsec := z.typeFromElem(ss, dns.TypeNSEC, do) - ret = append(ret, nsec...) - } - } - } - - } -Out: - return nil, ret, nil, rcode -} - -// Return type tp from e and add signatures (if they exists) and do is true. -func (z *Zone) typeFromElem(elem *tree.Elem, tp uint16, do bool) []dns.RR { - rrs := elem.Types(tp) - if do { - sigs := elem.Types(dns.TypeRRSIG) - sigs = signatureForSubType(sigs, tp) - if len(sigs) > 0 { - rrs = append(rrs, sigs...) - } - } - return rrs -} - -func (z *Zone) soa(do bool) []dns.RR { - if do { - ret := append([]dns.RR{z.Apex.SOA}, z.Apex.SIGSOA...) - return ret - } - return []dns.RR{z.Apex.SOA} -} - -func (z *Zone) ns(do bool) []dns.RR { - if do { - ret := append(z.Apex.NS, z.Apex.SIGNS...) - return ret - } - return z.Apex.NS -} - -// TODO(miek): should be better named, like aditionalProcessing? -func (z *Zone) searchCNAME(state request.Request, elem *tree.Elem, rrs []dns.RR) ([]dns.RR, []dns.RR, []dns.RR, Result) { - - qtype := state.QType() - do := state.Do() - - if do { - sigs := elem.Types(dns.TypeRRSIG) - sigs = signatureForSubType(sigs, dns.TypeCNAME) - if len(sigs) > 0 { - rrs = append(rrs, sigs...) - } - } - - targetName := rrs[0].(*dns.CNAME).Target - elem, _ = z.Tree.Search(targetName) - if elem == nil { - if !dns.IsSubDomain(z.origin, targetName) { - rrs = append(rrs, z.externalLookup(state, targetName, qtype)...) - } - return rrs, z.ns(do), nil, Success - } - - i := 0 - -Redo: - cname := elem.Types(dns.TypeCNAME) - if len(cname) > 0 { - rrs = append(rrs, cname...) - - if do { - sigs := elem.Types(dns.TypeRRSIG) - sigs = signatureForSubType(sigs, dns.TypeCNAME) - if len(sigs) > 0 { - rrs = append(rrs, sigs...) - } - } - targetName := cname[0].(*dns.CNAME).Target - elem, _ = z.Tree.Search(targetName) - if elem == nil { - if !dns.IsSubDomain(z.origin, targetName) { - if !dns.IsSubDomain(z.origin, targetName) { - rrs = append(rrs, z.externalLookup(state, targetName, qtype)...) - } - } - return rrs, z.ns(do), nil, Success - } - - i++ - if i > maxChain { - return rrs, z.ns(do), nil, Success - } - - goto Redo - } - - targets := cnameForType(elem.All(), qtype) - if len(targets) > 0 { - rrs = append(rrs, targets...) - - if do { - sigs := elem.Types(dns.TypeRRSIG) - sigs = signatureForSubType(sigs, qtype) - if len(sigs) > 0 { - rrs = append(rrs, sigs...) - } - } - } - - return rrs, z.ns(do), nil, Success -} - -func cnameForType(targets []dns.RR, origQtype uint16) []dns.RR { - ret := []dns.RR{} - for _, target := range targets { - if target.Header().Rrtype == origQtype { - ret = append(ret, target) - } - } - return ret -} - -func (z *Zone) externalLookup(state request.Request, target string, qtype uint16) []dns.RR { - m, e := z.Proxy.Lookup(state, target, qtype) - if e != nil { - // TODO(miek): debugMsg for this as well? Log? - return nil - } - return m.Answer -} - -// signatureForSubType range through the signature and return the correct ones for the subtype. -func signatureForSubType(rrs []dns.RR, subtype uint16) []dns.RR { - sigs := []dns.RR{} - for _, sig := range rrs { - if s, ok := sig.(*dns.RRSIG); ok { - if s.TypeCovered == subtype { - sigs = append(sigs, s) - } - } - } - return sigs -} - -// Glue returns any potential glue records for nsrrs. -func (z *Zone) Glue(nsrrs []dns.RR, do bool) []dns.RR { - glue := []dns.RR{} - for _, rr := range nsrrs { - if ns, ok := rr.(*dns.NS); ok && dns.IsSubDomain(ns.Header().Name, ns.Ns) { - glue = append(glue, z.searchGlue(ns.Ns, do)...) - } - } - return glue -} - -// searchGlue looks up A and AAAA for name. -func (z *Zone) searchGlue(name string, do bool) []dns.RR { - glue := []dns.RR{} - - // A - if elem, found := z.Tree.Search(name); found { - glue = append(glue, elem.Types(dns.TypeA)...) - if do { - sigs := elem.Types(dns.TypeRRSIG) - sigs = signatureForSubType(sigs, dns.TypeA) - glue = append(glue, sigs...) - } - } - - // AAAA - if elem, found := z.Tree.Search(name); found { - glue = append(glue, elem.Types(dns.TypeAAAA)...) - if do { - sigs := elem.Types(dns.TypeRRSIG) - sigs = signatureForSubType(sigs, dns.TypeAAAA) - glue = append(glue, sigs...) - } - } - return glue -} - -// additionalProcessing checks the current answer section and retrieves A or AAAA records -// (and possible SIGs) to need to be put in the additional section. -func additionalProcessing(z *Zone, answer []dns.RR, do bool) (extra []dns.RR) { - for _, rr := range answer { - name := "" - switch x := rr.(type) { - case *dns.SRV: - name = x.Target - case *dns.MX: - name = x.Mx - } - if !dns.IsSubDomain(z.origin, name) { - continue - } - - elem, _ := z.Tree.Search(name) - if elem == nil { - continue - } - - sigs := elem.Types(dns.TypeRRSIG) - for _, addr := range []uint16{dns.TypeA, dns.TypeAAAA} { - if a := elem.Types(addr); a != nil { - extra = append(extra, a...) - if do { - sig := signatureForSubType(sigs, addr) - extra = append(extra, sig...) - } - } - } - } - - return extra -} - -const maxChain = 8 |