@@ 18,9 18,55 @@ func Run(addr string, net string) error {
dns.HandleFunc(config.FeluConfig.DNSPattern, handleDNSRequest)
server := &dns.Server{
- Addr: addr,
- Net: net,
+ Addr: addr,
+ Net: net,
+ MsgAcceptFunc: msgAcceptFunc,
}
return server.ListenAndServe()
}
+
+// https://github.com/miekg/dns/blob/b77d1ed8e9282cadf21c4124f53a660fed55c8ca/types.go#L192
+const _QR = 1 << 15 // query/response (response=1)
+
+// Otherwise the same as the original, but:
+//
+// 1: Commented out dynamic update rejection.
+// 2: Commented out dh.Nscount > 1, for dynamic updates.
+//
+// TODO: Consider looking this over properly, and maybe ditching the default.
+//
+// https://github.com/miekg/dns/blob/b77d1ed8e9282cadf21c4124f53a660fed55c8ca/acceptfunc.go
+func msgAcceptFunc(dh dns.Header) dns.MsgAcceptAction {
+ if isResponse := dh.Bits&_QR != 0; isResponse {
+ return dns.MsgIgnore
+ }
+
+ /*
+ // Don't allow dynamic updates, because then the sections can contain a whole bunch of RRs.
+ opcode := int(dh.Bits>>11) & 0xF
+ if opcode != dns.OpcodeQuery && opcode != dns.OpcodeNotify {
+ return dns.MsgRejectNotImplemented
+ }
+ */
+
+ if dh.Qdcount != 1 {
+ return dns.MsgReject
+ }
+ // NOTIFY requests can have a SOA in the ANSWER section. See RFC 1996 Section 3.7 and 3.11.
+ if dh.Ancount > 1 {
+ return dns.MsgReject
+ }
+ /*
+ // IXFR request could have one SOA RR in the NS section. See RFC 1995, section 3.
+ if dh.Nscount > 1 {
+ return dns.MsgReject
+ }
+ */
+
+ if dh.Arcount > 2 {
+ return dns.MsgReject
+ }
+
+ return dns.MsgAccept
+}