diff options
Diffstat (limited to 'middleware/backend_lookup.go')
-rw-r--r-- | middleware/backend_lookup.go | 410 |
1 files changed, 0 insertions, 410 deletions
diff --git a/middleware/backend_lookup.go b/middleware/backend_lookup.go deleted file mode 100644 index 9e451feed..000000000 --- a/middleware/backend_lookup.go +++ /dev/null @@ -1,410 +0,0 @@ -package middleware - -import ( - "fmt" - "math" - "net" - "time" - - "github.com/coredns/coredns/middleware/etcd/msg" - "github.com/coredns/coredns/middleware/pkg/dnsutil" - "github.com/coredns/coredns/request" - - "github.com/miekg/dns" -) - -// A returns A records from Backend or an error. -func A(b ServiceBackend, zone string, state request.Request, previousRecords []dns.RR, opt Options) (records []dns.RR, err error) { - services, err := b.Services(state, false, opt) - if err != nil { - return nil, err - } - - for _, serv := range services { - - what, ip := serv.HostType() - - switch what { - case dns.TypeCNAME: - if Name(state.Name()).Matches(dns.Fqdn(serv.Host)) { - // x CNAME x is a direct loop, don't add those - continue - } - - newRecord := serv.NewCNAME(state.QName(), serv.Host) - if len(previousRecords) > 7 { - // don't add it, and just continue - continue - } - if dnsutil.DuplicateCNAME(newRecord, previousRecords) { - continue - } - - state1 := state.NewWithQuestion(serv.Host, state.QType()) - nextRecords, err := A(b, zone, state1, append(previousRecords, newRecord), opt) - - if err == nil { - // Not only have we found something we should add the CNAME and the IP addresses. - if len(nextRecords) > 0 { - records = append(records, newRecord) - records = append(records, nextRecords...) - } - continue - } - // This means we can not complete the CNAME, try to look else where. - target := newRecord.Target - if dns.IsSubDomain(zone, target) { - // We should already have found it - continue - } - // Lookup - m1, e1 := b.Lookup(state, target, state.QType()) - if e1 != nil { - continue - } - // Len(m1.Answer) > 0 here is well? - records = append(records, newRecord) - records = append(records, m1.Answer...) - continue - - case dns.TypeA: - records = append(records, serv.NewA(state.QName(), ip)) - - case dns.TypeAAAA: - // nodata? - } - } - return records, nil -} - -// AAAA returns AAAA records from Backend or an error. -func AAAA(b ServiceBackend, zone string, state request.Request, previousRecords []dns.RR, opt Options) (records []dns.RR, err error) { - services, err := b.Services(state, false, opt) - if err != nil { - return nil, err - } - - for _, serv := range services { - - what, ip := serv.HostType() - - switch what { - case dns.TypeCNAME: - // Try to resolve as CNAME if it's not an IP, but only if we don't create loops. - if Name(state.Name()).Matches(dns.Fqdn(serv.Host)) { - // x CNAME x is a direct loop, don't add those - continue - } - - newRecord := serv.NewCNAME(state.QName(), serv.Host) - if len(previousRecords) > 7 { - // don't add it, and just continue - continue - } - if dnsutil.DuplicateCNAME(newRecord, previousRecords) { - continue - } - - state1 := state.NewWithQuestion(serv.Host, state.QType()) - nextRecords, err := AAAA(b, zone, state1, append(previousRecords, newRecord), opt) - - if err == nil { - // Not only have we found something we should add the CNAME and the IP addresses. - if len(nextRecords) > 0 { - records = append(records, newRecord) - records = append(records, nextRecords...) - } - continue - } - // This means we can not complete the CNAME, try to look else where. - target := newRecord.Target - if dns.IsSubDomain(zone, target) { - // We should already have found it - continue - } - m1, e1 := b.Lookup(state, target, state.QType()) - if e1 != nil { - continue - } - // Len(m1.Answer) > 0 here is well? - records = append(records, newRecord) - records = append(records, m1.Answer...) - continue - // both here again - - case dns.TypeA: - // nada? - - case dns.TypeAAAA: - records = append(records, serv.NewAAAA(state.QName(), ip)) - } - } - return records, nil -} - -// SRV returns SRV records from the Backend. -// If the Target is not a name but an IP address, a name is created on the fly. -func SRV(b ServiceBackend, zone string, state request.Request, opt Options) (records, extra []dns.RR, err error) { - services, err := b.Services(state, false, opt) - if err != nil { - return nil, nil, err - } - - // Looping twice to get the right weight vs priority - w := make(map[int]int) - for _, serv := range services { - weight := 100 - if serv.Weight != 0 { - weight = serv.Weight - } - if _, ok := w[serv.Priority]; !ok { - w[serv.Priority] = weight - continue - } - w[serv.Priority] += weight - } - lookup := make(map[string]bool) - for _, serv := range services { - w1 := 100.0 / float64(w[serv.Priority]) - if serv.Weight == 0 { - w1 *= 100 - } else { - w1 *= float64(serv.Weight) - } - weight := uint16(math.Floor(w1)) - - what, ip := serv.HostType() - - switch what { - case dns.TypeCNAME: - srv := serv.NewSRV(state.QName(), weight) - records = append(records, srv) - - if _, ok := lookup[srv.Target]; ok { - break - } - - lookup[srv.Target] = true - - if !dns.IsSubDomain(zone, srv.Target) { - m1, e1 := b.Lookup(state, srv.Target, dns.TypeA) - if e1 == nil { - extra = append(extra, m1.Answer...) - } - - m1, e1 = b.Lookup(state, srv.Target, dns.TypeAAAA) - if e1 == nil { - // If we have seen CNAME's we *assume* that they are already added. - for _, a := range m1.Answer { - if _, ok := a.(*dns.CNAME); !ok { - extra = append(extra, a) - } - } - } - break - } - // Internal name, we should have some info on them, either v4 or v6 - // Clients expect a complete answer, because we are a recursor in their view. - state1 := state.NewWithQuestion(srv.Target, dns.TypeA) - addr, e1 := A(b, zone, state1, nil, opt) - if e1 == nil { - extra = append(extra, addr...) - } - // IPv6 lookups here as well? AAAA(zone, state1, nil). - - case dns.TypeA, dns.TypeAAAA: - serv.Host = msg.Domain(serv.Key) - srv := serv.NewSRV(state.QName(), weight) - - records = append(records, srv) - extra = append(extra, newAddress(serv, srv.Target, ip, what)) - } - } - return records, extra, nil -} - -// MX returns MX records from the Backend. If the Target is not a name but an IP address, a name is created on the fly. -func MX(b ServiceBackend, zone string, state request.Request, opt Options) (records, extra []dns.RR, err error) { - services, err := b.Services(state, false, opt) - if err != nil { - return nil, nil, err - } - - lookup := make(map[string]bool) - for _, serv := range services { - if !serv.Mail { - continue - } - what, ip := serv.HostType() - switch what { - case dns.TypeCNAME: - mx := serv.NewMX(state.QName()) - records = append(records, mx) - if _, ok := lookup[mx.Mx]; ok { - break - } - - lookup[mx.Mx] = true - - if !dns.IsSubDomain(zone, mx.Mx) { - m1, e1 := b.Lookup(state, mx.Mx, dns.TypeA) - if e1 == nil { - extra = append(extra, m1.Answer...) - } - - m1, e1 = b.Lookup(state, mx.Mx, dns.TypeAAAA) - if e1 == nil { - // If we have seen CNAME's we *assume* that they are already added. - for _, a := range m1.Answer { - if _, ok := a.(*dns.CNAME); !ok { - extra = append(extra, a) - } - } - } - break - } - // Internal name - state1 := state.NewWithQuestion(mx.Mx, dns.TypeA) - addr, e1 := A(b, zone, state1, nil, opt) - if e1 == nil { - extra = append(extra, addr...) - } - // e.AAAA as well - - case dns.TypeA, dns.TypeAAAA: - serv.Host = msg.Domain(serv.Key) - records = append(records, serv.NewMX(state.QName())) - extra = append(extra, newAddress(serv, serv.Host, ip, what)) - } - } - return records, extra, nil -} - -// CNAME returns CNAME records from the backend or an error. -func CNAME(b ServiceBackend, zone string, state request.Request, opt Options) (records []dns.RR, err error) { - services, err := b.Services(state, true, opt) - if err != nil { - return nil, err - } - - if len(services) > 0 { - serv := services[0] - if ip := net.ParseIP(serv.Host); ip == nil { - records = append(records, serv.NewCNAME(state.QName(), serv.Host)) - } - } - return records, nil -} - -// TXT returns TXT records from Backend or an error. -func TXT(b ServiceBackend, zone string, state request.Request, opt Options) (records []dns.RR, err error) { - services, err := b.Services(state, false, opt) - if err != nil { - return nil, err - } - - for _, serv := range services { - if serv.Text == "" { - continue - } - records = append(records, serv.NewTXT(state.QName())) - } - return records, nil -} - -// PTR returns the PTR records from the backend, only services that have a domain name as host are included. -func PTR(b ServiceBackend, zone string, state request.Request, opt Options) (records []dns.RR, err error) { - services, err := b.Reverse(state, true, opt) - if err != nil { - return nil, err - } - - for _, serv := range services { - if ip := net.ParseIP(serv.Host); ip == nil { - records = append(records, serv.NewPTR(state.QName(), serv.Host)) - } - } - return records, nil -} - -// NS returns NS records from the backend -func NS(b ServiceBackend, zone string, state request.Request, opt Options) (records, extra []dns.RR, err error) { - // NS record for this zone live in a special place, ns.dns.<zone>. Fake our lookup. - // only a tad bit fishy... - old := state.QName() - - state.Clear() - state.Req.Question[0].Name = "ns.dns." + zone - services, err := b.Services(state, false, opt) - if err != nil { - return nil, nil, err - } - // ... and reset - state.Req.Question[0].Name = old - - for _, serv := range services { - what, ip := serv.HostType() - switch what { - case dns.TypeCNAME: - return nil, nil, fmt.Errorf("NS record must be an IP address: %s", serv.Host) - - case dns.TypeA, dns.TypeAAAA: - serv.Host = msg.Domain(serv.Key) - records = append(records, serv.NewNS(state.QName())) - extra = append(extra, newAddress(serv, serv.Host, ip, what)) - } - } - return records, extra, nil -} - -// SOA returns a SOA record from the backend. -func SOA(b ServiceBackend, zone string, state request.Request, opt Options) ([]dns.RR, error) { - header := dns.RR_Header{Name: zone, Rrtype: dns.TypeSOA, Ttl: 300, Class: dns.ClassINET} - - Mbox := hostmaster + "." - Ns := "ns.dns." - if zone[0] != '.' { - Mbox += zone - Ns += zone - } - - soa := &dns.SOA{Hdr: header, - Mbox: Mbox, - Ns: Ns, - Serial: uint32(time.Now().Unix()), - Refresh: 7200, - Retry: 1800, - Expire: 86400, - Minttl: minTTL, - } - return []dns.RR{soa}, nil -} - -// BackendError writes an error response to the client. -func BackendError(b ServiceBackend, zone string, rcode int, state request.Request, err error, opt Options) (int, error) { - m := new(dns.Msg) - m.SetRcode(state.Req, rcode) - m.Authoritative, m.RecursionAvailable, m.Compress = true, true, true - m.Ns, _ = SOA(b, zone, state, opt) - - state.SizeAndDo(m) - state.W.WriteMsg(m) - // Return success as the rcode to signal we have written to the client. - return dns.RcodeSuccess, err -} - -func newAddress(s msg.Service, name string, ip net.IP, what uint16) dns.RR { - - hdr := dns.RR_Header{Name: name, Rrtype: what, Class: dns.ClassINET, Ttl: s.TTL} - - if what == dns.TypeA { - return &dns.A{Hdr: hdr, A: ip} - } - // Should always be dns.TypeAAAA - return &dns.AAAA{Hdr: hdr, AAAA: ip} -} - -const ( - minTTL = 60 - hostmaster = "hostmaster" -) |