GoToSocial/vendor/github.com/miekg/dns/acceptfunc.go
dependabot[bot] 9b03840b42
[chore]: Bump github.com/miekg/dns from 1.1.56 to 1.1.57 (#2439)
Bumps [github.com/miekg/dns](https://github.com/miekg/dns) from 1.1.56 to 1.1.57.
- [Changelog](https://github.com/miekg/dns/blob/master/Makefile.release)
- [Commits](https://github.com/miekg/dns/compare/v1.1.56...v1.1.57)

---
updated-dependencies:
- dependency-name: github.com/miekg/dns
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
2023-12-11 10:09:26 +00:00

60 lines
1.9 KiB
Go

package dns
// MsgAcceptFunc is used early in the server code to accept or reject a message with RcodeFormatError.
// It returns a MsgAcceptAction to indicate what should happen with the message.
type MsgAcceptFunc func(dh Header) MsgAcceptAction
// DefaultMsgAcceptFunc checks the request and will reject if:
//
// * isn't a request (don't respond in that case)
//
// * opcode isn't OpcodeQuery or OpcodeNotify
//
// * does not have exactly 1 question in the question section
//
// * has more than 1 RR in the Answer section
//
// * has more than 0 RRs in the Authority section
//
// * has more than 2 RRs in the Additional section
var DefaultMsgAcceptFunc MsgAcceptFunc = defaultMsgAcceptFunc
// MsgAcceptAction represents the action to be taken.
type MsgAcceptAction int
// Allowed returned values from a MsgAcceptFunc.
const (
MsgAccept MsgAcceptAction = iota // Accept the message
MsgReject // Reject the message with a RcodeFormatError
MsgIgnore // Ignore the error and send nothing back.
MsgRejectNotImplemented // Reject the message with a RcodeNotImplemented
)
func defaultMsgAcceptFunc(dh Header) MsgAcceptAction {
if isResponse := dh.Bits&_QR != 0; isResponse {
return 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 != OpcodeQuery && opcode != OpcodeNotify {
return MsgRejectNotImplemented
}
if dh.Qdcount != 1 {
return 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 MsgReject
}
// IXFR request could have one SOA RR in the NS section. See RFC 1995, section 3.
if dh.Nscount > 1 {
return MsgReject
}
if dh.Arcount > 2 {
return MsgReject
}
return MsgAccept
}