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Merge pull request #609 from rade/combine_nameserver_query_handlers

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refactor: eliminate duplication in nameserver query handlers
This commit is contained in:
Alvaro committed 2015-04-27 19:50:14 +02:00
2 parents e45ea65e45 ce4c79ed93
commit c2f55fc836
1 file changed
+39 -62
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nameserver/server.go
+39 -62
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@@ -215,70 +215,49 @@ func (s *DNSServer) Stop() error {
}
func (s *DNSServer) queryHandler(proto dnsProtocol) dns.HandlerFunc {
return func(w dns.ResponseWriter, r *dns.Msg) {
now := time.Now()
q := r.Question[0]
maxLen := getMaxReplyLen(r, proto)
lookups := []ZoneLookup{s.Zone, s.mdnsCli}
Debug.Printf("Query: %+v", q)
reply, err := s.cache.Get(r, maxLen, time.Now())
if err != nil {
if err == errNoLocalReplies {
Debug.Printf("[dns msgid %d] Cached 'no local replies' - skipping local lookup", r.MsgHdr.Id)
lookups = []ZoneLookup{s.Zone}
} else {
Debug.Printf("[dns msgid %d] Error from cache: %s", r.MsgHdr.Id, err)
w.WriteMsg(makeDNSFailResponse(r))
return
}
}
if reply != nil {
Debug.Printf("[dns msgid %d] Returning reply from cache: %s/%d answers",
r.MsgHdr.Id, dns.RcodeToString[reply.MsgHdr.Rcode], len(reply.Answer))
w.WriteMsg(reply)
return
zoneLookup := func(lookup ZoneLookup, q *dns.Question, r *dns.Msg) (*dns.Msg, []ZoneRecord, error) {
if ips, err := lookup.LookupName(q.Name); err != nil {
return nil, nil, err
} else {
return makeAddressReply(r, q, ips), ips, nil
}
}
// catch unsupported queries
if q.Qtype != dns.TypeA {
Debug.Printf("[dns msgid %d] Unsuported query type %s", r.MsgHdr.Id, dns.TypeToString[q.Qtype])
m := makeDNSNotImplResponse(r)
s.cache.Put(r, m, negLocalTTL, 0, now)
w.WriteMsg(m)
return
}
for _, lookup := range lookups {
if ips, err := lookup.LookupName(q.Name); err == nil {
m := makeAddressReply(r, &q, ips)
m.Authoritative = true
Debug.Printf("[dns msgid %d] Caching response for %s-query for \"%s\": %s [code:%s]",
m.MsgHdr.Id, dns.TypeToString[q.Qtype], q.Name, ips, dns.RcodeToString[m.Rcode])
s.cache.Put(r, m, nullTTL, 0, now)
w.WriteMsg(m)
return
}
now = time.Now()
}
Info.Printf("[dns msgid %d] No results for type %s query %s [caching no-local]",
r.MsgHdr.Id, dns.TypeToString[q.Qtype], q.Name)
s.cache.Put(r, nil, negLocalTTL, CacheNoLocalReplies, now)
fallback := func(w dns.ResponseWriter, r *dns.Msg) {
w.WriteMsg(makeDNSFailResponse(r))
}
return s.commonQueryHandler(proto, "Query", dns.TypeA, zoneLookup, fallback)
}
func (s *DNSServer) rdnsHandler(proto dnsProtocol) dns.HandlerFunc {
fallback := s.notUsHandler(proto)
zoneLookup := func(lookup ZoneLookup, q *dns.Question, r *dns.Msg) (*dns.Msg, []ZoneRecord, error) {
if names, err := lookup.LookupInaddr(q.Name); err != nil {
return nil, nil, err
} else {
return makePTRReply(r, q, names), names, nil
}
}
notUsHandler := s.notUsHandler(proto)
fallback := func(w dns.ResponseWriter, r *dns.Msg) {
Info.Printf("[dns msgid %d] -> sending to fallback server", r.MsgHdr.Id)
notUsHandler(w, r)
}
return s.commonQueryHandler(proto, "Reverse query", dns.TypePTR, zoneLookup, fallback)
}
func (s *DNSServer) commonQueryHandler(proto dnsProtocol, kind string, qtype uint16,
zoneLookup func(ZoneLookup, *dns.Question, *dns.Msg) (*dns.Msg, []ZoneRecord, error), fallback dns.HandlerFunc) dns.HandlerFunc {
return func(w dns.ResponseWriter, r *dns.Msg) {
q := r.Question[0]
Debug.Printf("[dns msgid %d] %s: %+v", r.MsgHdr.Id, kind, q)
now := time.Now()
q := r.Question[0]
maxLen := getMaxReplyLen(r, proto)
lookups := []ZoneLookup{s.Zone, s.mdnsCli}
maxLen := getMaxReplyLen(r, proto)
Debug.Printf("Reverse query: %+v", q)
reply, err := s.cache.Get(r, maxLen, time.Now())
if err != nil {
if err == errNoLocalReplies {
@@ -298,9 +277,8 @@ func (s *DNSServer) rdnsHandler(proto dnsProtocol) dns.HandlerFunc {
}
// catch unsupported queries
if q.Qtype != dns.TypePTR {
Warning.Printf("[dns msgid %d] Unexpected reverse query type %s: %+v",
r.MsgHdr.Id, dns.TypeToString[q.Qtype], q)
if q.Qtype != qtype {
Debug.Printf("[dns msgid %d] Unsupported query type %s", r.MsgHdr.Id, dns.TypeToString[q.Qtype])
m := makeDNSNotImplResponse(r)
s.cache.Put(r, m, negLocalTTL, 0, now)
w.WriteMsg(m)
@@ -308,12 +286,10 @@ func (s *DNSServer) rdnsHandler(proto dnsProtocol) dns.HandlerFunc {
}
for _, lookup := range lookups {
if names, err := lookup.LookupInaddr(q.Name); err == nil {
m := makePTRReply(r, &q, names)
if m, answers, err := zoneLookup(lookup, &q, r); err == nil {
m.Authoritative = true
Debug.Printf("[dns msgid %d] Caching response for %s-query for \"%s\": %s [code:%s]",
m.MsgHdr.Id, dns.TypeToString[q.Qtype], q.Name, names, dns.RcodeToString[m.Rcode])
Debug.Printf("[dns msgid %d] Caching response for type %s query for '%s': %s [code:%s]",
m.MsgHdr.Id, dns.TypeToString[q.Qtype], q.Name, answers, dns.RcodeToString[m.Rcode])
s.cache.Put(r, m, nullTTL, 0, now)
w.WriteMsg(m)
return
@@ -321,9 +297,10 @@ func (s *DNSServer) rdnsHandler(proto dnsProtocol) dns.HandlerFunc {
now = time.Now()
}
Info.Printf("[dns msgid %d] No results for %s-query about '%s' [caching no-local] -> sending to fallback server",
Info.Printf("[dns msgid %d] No results for type %s query for '%s' [caching no-local]",
r.MsgHdr.Id, dns.TypeToString[q.Qtype], q.Name)
s.cache.Put(r, nil, negLocalTTL, CacheNoLocalReplies, now)
fallback(w, r)
}
}