1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
|
// SPDX-License-Identifier: MIT
// Copyright © 2018-2020 WireGuard LLC. All Rights Reserved.
import Network
import Foundation
enum DNSResolver {}
extension DNSResolver {
/// Concurrent queue used for DNS resolutions
private static let resolverQueue = DispatchQueue(label: "DNSResolverQueue", qos: .default, attributes: .concurrent)
static func resolveSync(endpoints: [Endpoint?]) -> [Result<Endpoint, DNSResolutionError>?] {
let isAllEndpointsAlreadyResolved = endpoints.allSatisfy { maybeEndpoint -> Bool in
return maybeEndpoint?.hasHostAsIPAddress() ?? true
}
if isAllEndpointsAlreadyResolved {
return endpoints.map { endpoint in
return endpoint.map { .success($0) }
}
}
return endpoints.concurrentMap(queue: resolverQueue) { endpoint -> Result<Endpoint, DNSResolutionError>? in
guard let endpoint = endpoint else { return nil }
if endpoint.hasHostAsIPAddress() {
return .success(endpoint)
} else {
return Result { try DNSResolver.resolveSync(endpoint: endpoint) }
.mapError { error -> DNSResolutionError in
// swiftlint:disable:next force_cast
return error as! DNSResolutionError
}
}
}
}
private static func resolveSync(endpoint: Endpoint) throws -> Endpoint {
guard case .name(let name, _) = endpoint.host else {
return endpoint
}
var hints = addrinfo()
hints.ai_flags = AI_ALL // We set this to ALL so that we get v4 addresses even on DNS64 networks
hints.ai_family = AF_UNSPEC
hints.ai_socktype = SOCK_DGRAM
hints.ai_protocol = IPPROTO_UDP
var resultPointer: UnsafeMutablePointer<addrinfo>?
defer {
resultPointer.flatMap { freeaddrinfo($0) }
}
let errorCode = getaddrinfo(name, "\(endpoint.port)", &hints, &resultPointer)
if errorCode != 0 {
throw DNSResolutionError(errorCode: errorCode, address: name)
}
var ipv4Address: IPv4Address?
var ipv6Address: IPv6Address?
var next: UnsafeMutablePointer<addrinfo>? = resultPointer
let iterator = AnyIterator { () -> addrinfo? in
let result = next?.pointee
next = result?.ai_next
return result
}
for addrInfo in iterator {
if let maybeIpv4Address = IPv4Address(addrInfo: addrInfo) {
ipv4Address = maybeIpv4Address
break // If we found an IPv4 address, we can stop
} else if let maybeIpv6Address = IPv6Address(addrInfo: addrInfo) {
ipv6Address = maybeIpv6Address
continue // If we already have an IPv6 address, we can skip this one
}
}
// We prefer an IPv4 address over an IPv6 address
if let ipv4Address = ipv4Address {
return Endpoint(host: .ipv4(ipv4Address), port: endpoint.port)
} else if let ipv6Address = ipv6Address {
return Endpoint(host: .ipv6(ipv6Address), port: endpoint.port)
} else {
// Must never happen
fatalError()
}
}
}
extension Endpoint {
func withReresolvedIP() throws -> Endpoint {
#if os(iOS)
let hostname: String
switch host {
case .name(let name, _):
hostname = name
case .ipv4(let address):
hostname = "\(address)"
case .ipv6(let address):
hostname = "\(address)"
@unknown default:
fatalError()
}
var hints = addrinfo()
hints.ai_family = AF_UNSPEC
hints.ai_socktype = SOCK_DGRAM
hints.ai_protocol = IPPROTO_UDP
hints.ai_flags = AI_DEFAULT
var result: UnsafeMutablePointer<addrinfo>?
defer {
result.flatMap { freeaddrinfo($0) }
}
let errorCode = getaddrinfo(hostname, "\(self.port)", &hints, &result)
if errorCode != 0 {
throw DNSResolutionError(errorCode: errorCode, address: hostname)
}
let addrInfo = result!.pointee
if let ipv4Address = IPv4Address(addrInfo: addrInfo) {
return Endpoint(host: .ipv4(ipv4Address), port: port)
} else if let ipv6Address = IPv6Address(addrInfo: addrInfo) {
return Endpoint(host: .ipv6(ipv6Address), port: port)
} else {
fatalError()
}
#elseif os(macOS)
return self
#else
#error("Unimplemented")
#endif
}
}
/// An error type describing DNS resolution error
public struct DNSResolutionError: LocalizedError {
public let errorCode: Int32
public let address: String
init(errorCode: Int32, address: String) {
self.errorCode = errorCode
self.address = address
}
public var errorDescription: String? {
return String(cString: gai_strerror(errorCode))
}
}
|
