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author | Roopesh Chander <roop@roopc.net> | 2018-10-26 18:22:06 +0530 |
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committer | Roopesh Chander <roop@roopc.net> | 2018-10-27 19:07:16 +0530 |
commit | 3f4d12c4045e014a68fcd9cd8344a2c80fd349f8 (patch) | |
tree | 49ecbaaa35714b2774ccc5bcb6e4854675e4cdf5 /WireGuard/WireGuard/VPN | |
parent | Tunnel detail: UI for activating and deactivating a tunnel (diff) | |
download | wireguard-apple-3f4d12c4045e014a68fcd9cd8344a2c80fd349f8.tar.xz wireguard-apple-3f4d12c4045e014a68fcd9cd8344a2c80fd349f8.zip |
VPN: DNSResolver: A class that does DNS resolution using getaddrinfo
Signed-off-by: Roopesh Chander <roop@roopc.net>
Diffstat (limited to 'WireGuard/WireGuard/VPN')
-rw-r--r-- | WireGuard/WireGuard/VPN/DNSResolver.swift | 93 |
1 files changed, 93 insertions, 0 deletions
diff --git a/WireGuard/WireGuard/VPN/DNSResolver.swift b/WireGuard/WireGuard/VPN/DNSResolver.swift new file mode 100644 index 0000000..89b1a83 --- /dev/null +++ b/WireGuard/WireGuard/VPN/DNSResolver.swift @@ -0,0 +1,93 @@ +// SPDX-License-Identifier: MIT +// Copyright © 2018 WireGuard LLC. All rights reserved. + +import Network +import Foundation + +class DNSResolver { + let endpoints: [Endpoint] + + init(endpoints: [Endpoint]) { + self.endpoints = endpoints + } + + func resolve(completionHandler: @escaping ([Endpoint?]) -> Void) { + let endpoints = self.endpoints + DispatchQueue.global(qos: .userInitiated).async { + var resolvedEndpoints = Array<Endpoint?>(repeating: nil, count: endpoints.count) + for (i, endpoint) in endpoints.enumerated() { + let resolvedEndpoint = DNSResolver.resolveSync(endpoint: endpoint) + resolvedEndpoints[i] = resolvedEndpoint + } + DispatchQueue.main.async { + completionHandler(resolvedEndpoints) + } + } + } + + // Based on DNS resolution code by Jason Donenfeld <jason@zx2c4.com> + // in parse_endpoint() in src/tools/config.c in the WireGuard codebase + private static func resolveSync(endpoint: Endpoint) -> Endpoint? { + var hints = addrinfo( + ai_flags: 0, + ai_family: AF_UNSPEC, + ai_socktype: SOCK_DGRAM, // WireGuard is UDP-only + ai_protocol: IPPROTO_UDP, // WireGuard is UDP-only + ai_addrlen: 0, + ai_canonname: nil, + ai_addr: nil, + ai_next: nil) + var resultPointer = UnsafeMutablePointer<addrinfo>(OpaquePointer(bitPattern: 0)) + switch (endpoint.host) { + case .name(let name, _): + // The endpoint is a hostname and needs DNS resolution + let returnValue = getaddrinfo( + name.cString(using: .utf8), // Hostname + "\(endpoint.port)".cString(using: .utf8), // Port + &hints, + &resultPointer) + if (returnValue == 0) { + // getaddrinfo succeeded + let ipv4Buffer = UnsafeMutablePointer<Int8>.allocate(capacity: Int(INET_ADDRSTRLEN)) + let ipv6Buffer = UnsafeMutablePointer<Int8>.allocate(capacity: Int(INET6_ADDRSTRLEN)) + var ipv4AddressString: String? = nil + var ipv6AddressString: String? = nil + while (resultPointer != nil) { + let result = resultPointer!.pointee + resultPointer = result.ai_next + if (result.ai_family == AF_INET && result.ai_addrlen == INET_ADDRSTRLEN) { + if (inet_ntop(result.ai_family, result.ai_addr, ipv4Buffer, result.ai_addrlen) != nil) { + ipv4AddressString = String(cString: ipv4Buffer) + // If we found an IPv4 address, we can stop + break + } + } else if (result.ai_family == AF_INET6 && result.ai_addrlen == INET6_ADDRSTRLEN) { + if (ipv6AddressString != nil) { + // If we already have an IPv6 address, we can skip this one + continue + } + if (inet_ntop(result.ai_family, result.ai_addr, ipv6Buffer, result.ai_addrlen) != nil) { + ipv6AddressString = String(cString: ipv6Buffer) + } + } + } + ipv4Buffer.deallocate() + ipv6Buffer.deallocate() + // We prefer an IPv4 address over an IPv6 address + if let ipv4AddressString = ipv4AddressString, let ipv4Address = IPv4Address(ipv4AddressString) { + return Endpoint(host: NWEndpoint.Host.ipv4(ipv4Address), port: endpoint.port) + } else if let ipv6AddressString = ipv6AddressString, let ipv6Address = IPv6Address(ipv6AddressString) { + return Endpoint(host: NWEndpoint.Host.ipv6(ipv6Address), port: endpoint.port) + } else { + return nil + } + } else { + // getaddrinfo failed + return nil + } + default: + // The endpoint is already resolved + return endpoint + } + } +} |