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apple--containerization/Sources/Containerization/DNSConfiguration.swift
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chore: import upstream snapshot with attribution
2026-07-13 12:25:30 +08:00

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3.1 KiB
Swift

//===----------------------------------------------------------------------===//
// Copyright © 2025-2026 Apple Inc. and the Containerization 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 ContainerizationError
import ContainerizationExtras
/// DNS configuration for a container. The values will be used to
/// construct /etc/resolv.conf for a given container.
public struct DNS: Sendable {
/// The set of default nameservers to use if none are provided
/// in the constructor.
public static let defaultNameservers = ["1.1.1.1"]
/// The nameservers a container should use.
public var nameservers: [String]
/// The DNS domain to use.
public var domain: String?
/// The DNS search domains to use.
public var searchDomains: [String]
/// The DNS options to use.
public var options: [String]
public init(
nameservers: [String] = defaultNameservers,
domain: String? = nil,
searchDomains: [String] = [],
options: [String] = []
) {
self.nameservers = nameservers
self.domain = domain
self.searchDomains = searchDomains
self.options = options
}
/// Validates the DNS configuration.
///
/// Ensures that all nameserver entries are valid IPv4 or IPv6 addresses.
/// Arbitrary hostnames are not permitted as nameservers.
///
/// - Throws: ``ContainerizationError`` with code `.invalidArgument` if
/// any nameserver is not a valid IP address.
public func validate() throws {
for nameserver in nameservers {
let isValidIPv4 = (try? IPv4Address(nameserver)) != nil
let isValidIPv6 = (try? IPv6Address(nameserver)) != nil
if !isValidIPv4 && !isValidIPv6 {
throw ContainerizationError(
.invalidArgument,
message: "nameserver '\(nameserver)' is not a valid IPv4 or IPv6 address"
)
}
}
}
}
extension DNS {
public var resolvConf: String {
var text = ""
if !nameservers.isEmpty {
text += nameservers.map { "nameserver \($0)" }.joined(separator: "\n") + "\n"
}
if let domain {
text += "domain \(domain)\n"
}
if !searchDomains.isEmpty {
text += "search \(searchDomains.joined(separator: " "))\n"
}
if !options.isEmpty {
text += "options \(options.joined(separator: " "))\n"
}
return text
}
}