Fix IPv4/UInt32 calculations

CHANGELOG.md

@@ -15,6 +15,10 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 - Use high-level accessories instead of `debugLogKey` and `lastErrorKey`. [#45](https://github.com/keeshux/tunnelkit/pull/45)
 
+### Fixed
+
+- IPv4/UInt32 calculations were wrong.
+
 ## 1.2.2 (2018-10-25)
 
 ### Changed

TunnelKit/Sources/AppExtension/DNSResolver.swift

@@ -96,10 +96,10 @@ public class DNSResolver {
     }
 
     public static func string(fromIPv4 ipv4: UInt32) -> String {
-        let a = UInt8(ipv4 & UInt32(0xff))
-        let b = UInt8((ipv4 >> 8) & UInt32(0xff))
-        let c = UInt8((ipv4 >> 16) & UInt32(0xff))
-        let d = UInt8((ipv4 >> 24) & UInt32(0xff))
+        let a = UInt8((ipv4 >> 24) & UInt32(0xff))
+        let b = UInt8((ipv4 >> 16) & UInt32(0xff))
+        let c = UInt8((ipv4 >> 8) & UInt32(0xff))
+        let d = UInt8(ipv4 & UInt32(0xff))
 
         return "\(a).\(b).\(c).\(d)"
     }
@@ -110,13 +110,13 @@ public class DNSResolver {
             return nil
         }
         var ipv4: UInt32 = 0
-        var bits: UInt32 = 0
+        var bits: UInt32 = 32
         comps.forEach {
             guard let octet = UInt32($0), octet <= 255 else {
                 return
             }
+            bits -= 8
             ipv4 |= octet << bits
-            bits += 8
         }
         return ipv4
     }

TunnelKitTests/DNSTests.swift

@@ -38,7 +38,7 @@ class DNSTests: XCTestCase {
 
     func testIPv4() {
         let addr = "1.2.3.4"
-        let ip: UInt32 = 0x04030201
+        let ip: UInt32 = 0x01020304
         
         XCTAssertEqual(DNSResolver.ipv4(fromString: addr), ip)
         XCTAssertEqual(DNSResolver.string(fromIPv4: ip), addr)