Files
container/Sources/DNSServer/Handlers/HostTableResolver.swift
T
Kathryn Baldauf d6f052d206 Update license header on all files to include the current year (#1024)
## Motivation and Context
Now that we're in 2026, we need to update the license headers on all the
files. Unfortunately, Hawkeye doesn't have an attribute for the current
year to help us avoid this in the future. Instead, I had to work around
this by doing the following:

1. Update licenserc.toml with:
     ```
      [properties]
       ... (other properties)
       currentYear = "2026"
     ```
 
2. Update scripts/license-header.txt with
    ```
Copyright ©{{ " " }}{%- set created = attrs.git_file_created_year or
attrs.disk_file_created_year -%}{%- set modified = props["currentYear"]
-%}{%- if created != modified -%} {{created}}-{{modified}}{%- else
-%}{{created}}{%- endif -%}{{ " " }}{{ props["copyrightOwner"] }}.
    ```

Then I removed these two changes before committing. After this PR is
merged, all files will have recently had git updates, so the existing
code for setting the modified year should work as intended.

Signed-off-by: Kathryn Baldauf <k_baldauf@apple.com>
2026-01-05 13:09:34 -08:00

99 lines
3.5 KiB
Swift

//===----------------------------------------------------------------------===//
// Copyright © 2025-2026 Apple Inc. and the container project authors.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// https://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//===----------------------------------------------------------------------===//
import DNS
/// Handler that uses table lookup to resolve hostnames.
public struct HostTableResolver: DNSHandler {
public let hosts4: [String: IPv4]
private let ttl: UInt32
public init(hosts4: [String: IPv4], ttl: UInt32 = 300) {
self.hosts4 = hosts4
self.ttl = ttl
}
public func answer(query: Message) async throws -> Message? {
let question = query.questions[0]
let record: ResourceRecord?
switch question.type {
case ResourceRecordType.host:
record = answerHost(question: question)
case ResourceRecordType.host6:
// Return NODATA (noError with empty answers) for AAAA queries ONLY if A record exists.
// This is required because musl libc has issues when A record exists but AAAA returns NXDOMAIN.
// musl treats NXDOMAIN on AAAA as "domain doesn't exist" and fails DNS resolution entirely.
// NODATA correctly indicates "no IPv6 address available, but domain exists".
if hosts4[question.name] != nil {
return Message(
id: query.id,
type: .response,
returnCode: .noError,
questions: query.questions,
answers: []
)
}
// If hostname doesn't exist, return nil which will become NXDOMAIN
return nil
case ResourceRecordType.nameServer,
ResourceRecordType.alias,
ResourceRecordType.startOfAuthority,
ResourceRecordType.pointer,
ResourceRecordType.mailExchange,
ResourceRecordType.text,
ResourceRecordType.service,
ResourceRecordType.incrementalZoneTransfer,
ResourceRecordType.standardZoneTransfer,
ResourceRecordType.all:
return Message(
id: query.id,
type: .response,
returnCode: .notImplemented,
questions: query.questions,
answers: []
)
default:
return Message(
id: query.id,
type: .response,
returnCode: .formatError,
questions: query.questions,
answers: []
)
}
guard let record else {
return nil
}
return Message(
id: query.id,
type: .response,
returnCode: .noError,
questions: query.questions,
answers: [record]
)
}
private func answerHost(question: Question) -> ResourceRecord? {
guard let ip = hosts4[question.name] else {
return nil
}
return HostRecord<IPv4>(name: question.name, ttl: ttl, ip: ip)
}
}