aboutsummaryrefslogtreecommitdiff
path: root/middleware/backend_lookup.go
diff options
context:
space:
mode:
Diffstat (limited to 'middleware/backend_lookup.go')
-rw-r--r--middleware/backend_lookup.go410
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"
-)
generated by cgit v1.2.3 (git 2.39.1) at 2025-07-24 04:18:25 +0000