fix various issues in icmp channel; add icmp header rewrite and corre…

…sponding tests

Sources/LCLPing/Models/Errors+LCLPing.swift

@@ -73,6 +73,8 @@ public enum PingError: Error {
     case httpUnableToEstablishTLSConnection
     case httpMissingResult
 
+    case invalidHexFormat
+
     case forTestingPurposeOnly
 }
 

Sources/LCLPing/Models/PingSummary.swift

@@ -36,7 +36,7 @@ extension PingSummary {
             return lhs.seqNum == rhs.seqNum
         }
 
-        public let seqNum: UInt16
+        public let seqNum: UInt16?
         public let reason: String
     }
 }

Sources/LCLPing/TestUtils/Rewritable.swift

@@ -14,36 +14,16 @@ import Foundation
 import NIOCore
 
 protocol Rewritable {
-//    var allKeyPaths: [PartialKeyPath<Self>] { get }
     func rewrite(newValues: [PartialKeyPath<Self> : AnyObject]) -> Self
 }
 
 extension ICMPRequestPayload: Rewritable {
-//    var allKeyPaths: [PartialKeyPath<ICMPRequestPayload>] {
-//        return [\.identifier, \.timestamp]
-//    }
-
     func rewrite(newValues: [PartialKeyPath<ICMPRequestPayload> : AnyObject]) -> ICMPRequestPayload {
         return ICMPRequestPayload(timestamp: newValues[\.timestamp] as? TimeInterval ?? self.timestamp, identifier: newValues[\.identifier] as? UInt16 ?? self.identifier)
     }
 }
 
 extension IPv4Header: Rewritable {
-//    var allKeyPaths: [PartialKeyPath<IPv4Header>] {
-//        return [
-//            \.versionAndHeaderLength,
-//            \.differentiatedServicesAndECN,
-//            \.totalLength,
-//            \.identification,
-//            \.flagsAndFragmentOffset,
-//            \.timeToLive,
-//            \.protocol,
-//            \.headerChecksum,
-//            \.sourceAddress,
-//            \.destinationAddress
-//        ]
-//    }
-
     func rewrite(newValues: [PartialKeyPath<IPv4Header> : AnyObject]) -> IPv4Header {
         return IPv4Header(
             versionAndHeaderLength: newValues[\.versionAndHeaderLength] as? UInt8 ?? self.versionAndHeaderLength, 
@@ -61,17 +41,6 @@ extension IPv4Header: Rewritable {
 }
 
 extension ICMPHeader: Rewritable {
-//    var allKeyPaths: [PartialKeyPath<ICMPHeader>] {
-//        return [
-//            \.type,
-//            \.code,
-//            \.checkSum,
-//            \.idenifier,
-//            \.sequenceNum,
-//            \.payload
-//        ]
-//    }
-
     func rewrite(newValues: [PartialKeyPath<ICMPHeader> : AnyObject]) -> ICMPHeader {
         var newHeader = ICMPHeader(
             type: newValues[\.type] as? UInt8 ?? self.type, 
@@ -85,25 +54,41 @@ extension ICMPHeader: Rewritable {
     }
 }
 
-extension AddressedEnvelope: Rewritable where DataType: Rewritable {
-//    var allKeyPaths: [PartialKeyPath<NIOCore.AddressedEnvelope<DataType>>] {
-//        return [
-//            \.remoteAddress,
-//            \.data
-//        ]
-//    }
-
+extension AddressedEnvelope: Rewritable where DataType == ByteBuffer {
     func rewrite(newValues: [PartialKeyPath<NIOCore.AddressedEnvelope<DataType>> : AnyObject]) -> NIOCore.AddressedEnvelope<DataType> {
         return AddressedEnvelope(
             remoteAddress: newValues[\.remoteAddress] as? SocketAddress ?? self.remoteAddress,
-            data: data.rewrite(newValues: newValues[\.data] as! [PartialKeyPath<DataType> : AnyObject])
+            data: data.rewrite(newValues: newValues[\AddressedEnvelope.data] as? [RewriteData] ?? [RewriteData(index: 0, byte: 0x55)])
         )
     }
 }
 
-// TODO: implement Bytebuffer
-extension ByteBuffer: Rewritable {
-    func rewrite(newValues: [PartialKeyPath<NIOCore.ByteBuffer> : AnyObject]) -> NIOCore.ByteBuffer {
-        return ByteBuffer(buffer: self)
+
+extension ByteBuffer {
+    func rewrite(newValues: ByteBuffer) -> NIOCore.ByteBuffer {
+        print("[ByteBuffer Rewrite]: received new value: \(newValues.readableBytesView)")
+        return ByteBuffer(buffer: newValues)
+    }
+
+    func rewrite(newValues: [RewriteData]) -> ByteBuffer {
+        print("[ByteBuffer Rewrite]: received new value: \(newValues)")
+        var newBuffer = ByteBuffer(buffer: self)
+        for newValue in newValues {
+            newBuffer.setBytes(newValue.byte.data, at: newValue.index)
+        }
+        print("ByteBuffer Rewrite: rewritten as \(newBuffer.readableBytesView)")
+        return newBuffer
+    }
+}
+
+extension Int8 {
+    var data: Data {
+        var int = self
+        return Data(bytes: &int, count: MemoryLayout<Int8>.size)
     }
 }
+
+struct RewriteData {
+    let index: Int
+    let byte: Int8
+}

Sources/LCLPing/Utilities/Hex.swift

@@ -0,0 +1,53 @@
+//
+// This source file is part of the LCLPing open source project
+//
+// Copyright (c) 2021-2023 Local Connectivity Lab and the project authors
+// Licensed under Apache License v2.0
+//
+// See LICENSE for license information
+// See CONTRIBUTORS for the list of project authors
+//
+// SPDX-License-Identifier: Apache-2.0
+//
+
+import Foundation
+
+
+let charA = UInt8(UnicodeScalar("a").value)
+let char0 = UInt8(UnicodeScalar("0").value)
+
+private func itoh(_ value: UInt8) -> UInt8 {
+    return (value > 9) ? (charA + value - 10) : (char0 + value)
+}
+
+private func htoi(_ value: UInt8) throws -> UInt8 {
+    switch value {
+    case char0...char0 + 9:
+        return value - char0
+    case charA...charA + 5:
+        return value - charA + 10
+    default:
+        throw PingError.invalidHexFormat
+    }
+}
+
+extension Data {
+
+    /// Initialize the `Data` from the hex string value
+    init(hexString: String) throws {
+        self.init()
+
+        if hexString.count % 2 != 0 || hexString.count == 0 {
+            throw PingError.invalidHexFormat
+        }
+
+        let stringBytes: [UInt8] = Array(hexString.lowercased().data(using: String.Encoding.utf8)!)
+
+        for i in stride(from: stringBytes.startIndex, to: stringBytes.endIndex - 1, by: 2) {
+            let char1 = stringBytes[i]
+            let char2 = stringBytes[i + 1]
+
+            try self.append(htoi(char1) << 4 + htoi(char2))
+        }
+    }
+}

Sources/LCLPing/Utilities/Utilities.swift

@@ -81,7 +81,7 @@ internal func summarizePingResponse(_ pingResponses: [PingResponse], host: Socke
             timeout.insert(sequenceNum)
         case .error(let seqNum, let error):
             errorCount += 1
-            if let seqNum = seqNum, let error = error {
+            if let error = error {
                 errors.insert(PingSummary.PingErrorSummary(seqNum: seqNum, reason: error.localizedDescription))
             }
         }

Tests/ICMPChannelTests/ICMPDuplexerTests.swift

@@ -86,9 +86,6 @@ final class ICMPDuplexerTests: XCTestCase {
     }
 
     func testReadFireCorrectError() {
-        XCTAssertNoThrow(try channel.pipeline.addHandler(ICMPDuplexer(configuration: self.icmpConfiguration)).wait())
-        channel.pipeline.fireChannelActive()
-
         let inputs = [
             (3, 0, PingError.icmpDestinationNetworkUnreachable),
             (3, 1, PingError.icmpDestinationHostUnreachable),
@@ -123,10 +120,17 @@ final class ICMPDuplexerTests: XCTestCase {
         for input in inputs {
             let (type, code, expectedError) = input
             var inboundInData: ICMPHeader = ICMPHeader(type: UInt8(type), code: UInt8(code), idenifier: 0xbeef, sequenceNum: 2)
+            let outboundInData: ICMPOutboundIn = (UInt16(0xbeef), UInt16(2))
             inboundInData.setChecksum()
             do {
+                let channel = EmbeddedChannel()
+                let loop = channel.embeddedEventLoop
+                XCTAssertNoThrow(try channel.pipeline.addHandler(ICMPDuplexer(configuration: self.icmpConfiguration)).wait())
+                channel.pipeline.fireChannelActive()
+
+                try channel.writeOutbound(outboundInData)
                 try channel.writeInbound(inboundInData)
-                self.loop.run()
+                loop.run()
                 let inboundInResult = try channel.readInbound(as: PingResponse.self)!
                 switch inboundInResult {
                 case .error(.some(let seqNum), .some(let error)):