sneak
9282119b41
check / check (push) Waiting to run
The resolver lists in FailedTypes each record type whose query to a nameserver got no usable reply (no reply, a code other than NOERROR or NXDOMAIN, a referral, or a truncated reply whose TCP retry failed) and logs it unless shutdown cut it short. A nameserver that answered no type has failed. The watcher saves such a type in failedTypes with the previous check's records, leaves it out of the comparison with other nameservers on that check, and compares it with the next answer. When the previous check did not know its records either, it is also in unknownTypes and not compared until it answers. A nameserver whose A, AAAA or CNAME query failed is no answer when following a CNAME or resolving addresses. Model: opus-5-5
53 lines
1.7 KiB
Go
53 lines
1.7 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",
|
|
)
|
|
|
|
// ErrTruncated is the reason given for a reply too large for UDP
|
|
// whose retry over TCP failed.
|
|
ErrTruncated = errors.New(
|
|
"reply truncated and its retry over TCP failed",
|
|
)
|
|
|
|
// 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",
|
|
)
|
|
|
|
// ErrLookupDepthExceeded is returned when nameserver addresses
|
|
// were not looked up because lookups were already maxLookupDepth
|
|
// deep, one inside another.
|
|
ErrLookupDepthExceeded = errors.New(
|
|
"lookups of nameserver addresses go too deep",
|
|
)
|
|
|
|
// ErrContextCanceled wraps context cancellation for the
|
|
// resolver's iterative queries.
|
|
ErrContextCanceled = errors.New("context canceled")
|
|
)
|