Files
dnswatcher/internal/resolver/errors.go
T
sneak c3f2a7ab16
check / check (push) Failing after 2m28s
resolver: never resend a refused query asking for recursion (closes #206)
queryDNS resent a query that a server refused, this time asking for
recursion, so on a network that intercepts DNS the answers could come
from a recursive resolver without anyone knowing. A refusal is now only
a refusal, and the server is passed over for the next.

When every server of a zone refuses, the error says so. When every root
server refuses, the error is ErrIntercepted: root servers refuse no
query, so something on the network is answering in their place.
FindAuthoritativeNameservers stops at that error instead of trying each
parent name, so the watcher's log line says it.

A live test asks Quad9, which refuses a query not asking for recursion,
so that the resend cannot come back unnoticed.

Model: opus-5-5
2026-10-02 01:16:46 +00:00

40 lines
1.3 KiB
Go

package resolver
import "errors"
// Sentinel errors returned by the resolver.
var (
// ErrNoNameservers is returned when no authoritative NS
// could be discovered for a domain.
ErrNoNameservers = errors.New(
"no authoritative nameservers found",
)
// ErrNoNameserverAnswered is returned when every nameserver
// asked about a name timed out, failed or returned a referral,
// so whether the name has addresses is unknown.
ErrNoNameserverAnswered = errors.New("no nameserver answered")
// ErrUnusableReply is returned when a server replied with an
// error such as SERVFAIL, or with a referral that leads no
// closer to the name asked about.
ErrUnusableReply = errors.New(
"reply is an error or a referral that leads no closer",
)
// ErrIntercepted is returned when every root server refused a
// query. Root servers refuse no query, so the refusals came from
// something on the network answering in their place.
ErrIntercepted = errors.New("this network intercepts DNS queries")
// ErrCNAMEDepthExceeded is returned when a CNAME chain
// exceeds MaxCNAMEDepth.
ErrCNAMEDepthExceeded = errors.New(
"CNAME chain depth exceeded",
)
// ErrContextCanceled wraps context cancellation for the
// resolver's iterative queries.
ErrContextCanceled = errors.New("context canceled")
)