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Updates to Swift UDP #42

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Merged
agnosticdev merged 5 commits into from
Jul 6, 2026
Merged

Updates to Swift UDP #42

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98ffa5f
Updates to Swift UDP
agnosticdev Jul 3, 2026
1c526ad
agnosticdev/UpdateUDP: Added fullChecksumOffload to protocol options
agnosticdev Jul 3, 2026
2f4aa40
agnosticdev/UpdateUDP: Added testable import
agnosticdev Jul 3, 2026
6946f2f
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agnosticdev Jul 6, 2026
93ccf9e
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agnosticdev Jul 6, 2026
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22 changes: 22 additions & 0 deletions Sources/SwiftNetwork/Protocols/Checksum.swift
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Original file line number Diff line number Diff line change
Expand Up @@ -57,6 +57,23 @@ enum ChecksumError: Error {
case invalidBuffer
}

struct ChecksumFlags: OptionSet {
let rawValue: UInt8
static let partial = ChecksumFlags(rawValue: 0x01)
static let zeroInvert = ChecksumFlags(rawValue: 0x02)
static let ip = ChecksumFlags(rawValue: 0x04)
static let tcpIPv4 = ChecksumFlags(rawValue: 0x08)
static let udpIPv4 = ChecksumFlags(rawValue: 0x10)
static let tcpIPv6 = ChecksumFlags(rawValue: 0x20)
static let udpIPv6 = ChecksumFlags(rawValue: 0x40)
}

struct InterfaceChecksumFlags: OptionSet {
let rawValue: UInt32
static let udpIPv4 = InterfaceChecksumFlags(rawValue: 0x0000_0004)
static let udpIPv6 = InterfaceChecksumFlags(rawValue: 0x0000_0040)
}

@available(Network 0.1.0, *)
extension IPv6Address {
func checksum() -> UInt32 {
Expand Down Expand Up @@ -141,6 +158,11 @@ extension Frame {
return ((~value) & 0xffff)
}

mutating func setInternetChecksum(flags: ChecksumFlags, startOffset: UInt16, checksumOffset: UInt16) -> Bool {
checksumOffloadFlags |= flags.rawValue
return false
}

mutating func finalizeIPChecksum(checksumOffset: Int, zeroInvert: Bool) throws(ChecksumError) {
let unclaimedLength = self.unclaimedLength
if unclaimedLength == 0 {
Expand Down
4 changes: 4 additions & 0 deletions Sources/SwiftNetwork/Protocols/HarnessProtocols.swift
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Original file line number Diff line number Diff line change
Expand Up @@ -237,6 +237,10 @@ public class UpperHarness<LinkageType: InboundDataLinkage>: UpperHarnessProtocol
return invokeGetMetadata() as? ProtocolMetadata<P>
}

final public func getMetrics(requestedNetworkMetric: RequestedNetworkMetrics) -> NetworkMetrics? {
lower.invokeGetMetrics(reference, requestedNetworkMetric: requestedNetworkMetric)
}

public func setApplicationError(_ applicationError: UInt64, applicationErrorReason: String) {
if let metadata: ProtocolMetadata<QUICProtocol> = self.getMetadata() {
metadata.perProtocolMetadata?.quicConnectionMetadata?.applicationError = applicationError
Expand Down
92 changes: 77 additions & 15 deletions Sources/SwiftNetwork/Protocols/UDPProtocol.swift
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Original file line number Diff line number Diff line change
Expand Up @@ -48,6 +48,7 @@ public struct UDPProtocol: NetworkProtocol {
static public let noMetadata = UDPOptions(rawValue: 1 << 1)
static public let ignoreInboundChecksum = UDPOptions(rawValue: 1 << 2)
static public let useQUICStats = UDPOptions(rawValue: 1 << 3)
static public let fullChecksumOffload = UDPOptions(rawValue: 1 << 4)

#if NETWORK_PRIVATE
var privateStorage = UDPProtocolOptionsPrivateStorage()
Expand Down Expand Up @@ -97,7 +98,9 @@ public struct UDPProtocol: NetworkProtocol {
var eventManager = ProtocolEventManager()

// Only called by newProtocolInstance()
fileprivate static func registerNewUDP(on context: NetworkContext) -> ProtocolInstanceReference {
fileprivate static func registerNewUDP(
on context: NetworkContext,
) -> ProtocolInstanceReference {
let udp = UDPInstance(context: context)
let registeredIndex = context.registerUDPInstance(udp)
context.udpInstances[registeredIndex].udpInstanceIndex = registeredIndex
Expand All @@ -121,6 +124,9 @@ public struct UDPProtocol: NetworkProtocol {

var serviceClass = Parameters.ServiceClass.bestEffort
var maximumDatagramSize: Int = 0
var isIPv4: Bool {
flags.contains(.isIPv4)
}

struct Flags: OptionSet {
init(rawValue: Self.RawValue) {
Expand Down Expand Up @@ -153,6 +159,13 @@ public struct UDPProtocol: NetworkProtocol {
if self.maximumDatagramSize > UDPProtocol.headerLength {
self.maximumDatagramSize -= UDPProtocol.headerLength
}
let udpChecksumOffload: UInt32 = path.hardwareChecksumFlags
if isIPv4 && ((udpChecksumOffload & InterfaceChecksumFlags.udpIPv4.rawValue) != 0)
|| !isIPv4 && ((udpChecksumOffload & InterfaceChecksumFlags.udpIPv6.rawValue) != 0)
{
self.flags.insert(.fullChecksumOffload)
self.flags.remove(.partialChecksumOffload)
}
}

mutating func setup(
Expand Down Expand Up @@ -202,6 +215,21 @@ public struct UDPProtocol: NetworkProtocol {
if udpOptions.ignoreInboundChecksum {
self.flags.insert(.ignoreInboundChecksum)
}
if udpOptions.fullChecksumOffload {
self.flags.insert(.fullChecksumOffload)
}
#if !NETWORK_EMBEDDED
if let transport = parameters.defaultStack.transport {
if transport.options == udpOptions, udpOptions.useQUICStats {
self.flags.insert(.upperTransportIsQUIC)
} else if let quicOptions = transport.options,
quicOptions.matches(identifier: QUICStreamProtocol.identifier)
|| quicOptions.matches(identifier: QUICConnectionProtocol.identifier)
{
self.flags.insert(.upperTransportIsQUIC)
}
}
#endif
}
}

Expand All @@ -213,7 +241,7 @@ public struct UDPProtocol: NetworkProtocol {
let inbound = (inboundChecksum != nil)
let existingChecksum: UInt16 = inboundChecksum ?? 0
var checksumValue: UInt16 = 0
if self.flags.contains(.isIPv4) {
if isIPv4 {
checksumValue = Checksum.ipv4PseudoHeader(
source: inbound ? ipv4Remote : ipv4Local,
dest: inbound ? ipv4Local : ipv4Remote,
Expand Down Expand Up @@ -295,7 +323,7 @@ public struct UDPProtocol: NetworkProtocol {
return .removeFrameAndContinue
}

guard self.flags.contains(.isIPv4) || checksum != 0 else {
guard isIPv4 || checksum != 0 else {
log.error("Received an IPv6 packet with zero checksum")
frame.finalize(success: false)
return .removeFrameAndContinue
Expand Down Expand Up @@ -391,7 +419,7 @@ public struct UDPProtocol: NetworkProtocol {
frame.serviceClass = self.serviceClass
}

if !self.flags.contains(.isIPv4) || !self.flags.contains(.noChecksum) {
if !isIPv4 || !self.flags.contains(.noChecksum) {
// Always insert pseudo header checksum
let checksumValue = pseudoHeaderChecksum(inboundChecksum: nil, length: length)

Expand All @@ -407,23 +435,41 @@ public struct UDPProtocol: NetworkProtocol {
return .removeFrameAndContinue
}

let finalizedChecksum = false
if self.flags.contains(.fullChecksumOffload) {
// TODO: Checksum offload
} else if self.flags.contains(.partialChecksumOffload) {
// TODO: Checksum offload
let csumFlags: ChecksumFlags =
isIPv4
? [.udpIPv4, .zeroInvert]
: [.udpIPv6, .zeroInvert]
frame.checksumOffloadFlags |= csumFlags.rawValue
}

if !finalizedChecksum {
do throws(ChecksumError) {
try frame.finalizeIPChecksum(checksumOffset: checksumOffset, zeroInvert: true)
} catch {
log.error("Failed to finalize UDP checksum")
frame.finalize(success: false)
return .removeFrameAndContinue
if !self.flags.contains(.fullChecksumOffload) {
var checksumOffloadDisabled = !self.flags.contains(.partialChecksumOffload)
if !checksumOffloadDisabled {
let csumStart = UInt16(isIPv4 ? IPProtocol.ipv4HeaderLength : IPProtocol.ipv6HeaderLength)
let csumWrite = csumStart + UInt16(checksumOffset)
let csumFlags: ChecksumFlags = [.partial, .zeroInvert]
if !frame.setInternetChecksum(
flags: csumFlags,
startOffset: csumStart,
checksumOffset: csumWrite
) {
checksumOffloadDisabled = true
}
}

if checksumOffloadDisabled {
do throws(ChecksumError) {
try frame.finalizeIPChecksum(checksumOffset: checksumOffset, zeroInvert: true)
} catch {
log.error("Failed to finalize UDP checksum")
frame.finalize(success: false)
return .removeFrameAndContinue
}
}
}
}
transmitByteCount += length - UDPProtocol.headerLength

return .continueIterating
}
Expand All @@ -434,6 +480,11 @@ public struct UDPProtocol: NetworkProtocol {
#if !NETWORK_EMBEDDED
var metadata: AbstractProtocolMetadata? { nil }
#endif

func updateDataTransferSnapshot(_ snapshot: inout DataTransferSnapshot) {
snapshot.receivedTransportByteCount = UInt64(receiveByteCount)
snapshot.sentTransportByteCount = UInt64(transmitByteCount)
}
}

public init() {}
Expand Down Expand Up @@ -506,4 +557,15 @@ extension ProtocolOptions<UDPProtocol> {
}
}
}

public var fullChecksumOffload: Bool {
get { perProtocolOptions!.contains(.fullChecksumOffload) }
set {
if newValue {
perProtocolOptions!.insert(.fullChecksumOffload)
} else {
perProtocolOptions!.remove(.fullChecksumOffload)
}
}
}
}
12 changes: 8 additions & 4 deletions Tests/SwiftNetworkTests/SwiftNetworkMultiplexingTests.swift
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Original file line number Diff line number Diff line change
Expand Up @@ -25,6 +25,10 @@ import XCTest
@available(Network 0.1.0, *)
final class SwiftNetworkMultiplexingTests: NetTestCase {

// 10.0.0.20
static let localIPv4Address: [UInt8] = [0x0a, 0x00, 0x00, 0x14]
// 10.0.0.117
static let remoteIPv4Address: [UInt8] = [0x0a, 0x00, 0x00, 0x75]
static let outputMessage: [UInt8] = [0x0a, 0x0b, 0x0c, 0x0d]
static let inputMessage: [UInt8] = [0x0d, 0x0c, 0x0b, 0x0a, 0x01]

Expand All @@ -33,8 +37,8 @@ final class SwiftNetworkMultiplexingTests: NetTestCase {
let context = parameters.context
let path = PathProperties(parameters: parameters)

let localEndpoint = Endpoint(address: IPv4Address(SwiftNetworkUDPTests.localIPv4Address)!, port: 1234)
let remoteEndpoint = Endpoint(address: IPv4Address(SwiftNetworkUDPTests.localIPv4Address)!, port: 2345)
let localEndpoint = Endpoint(address: IPv4Address(SwiftNetworkMultiplexingTests.localIPv4Address)!, port: 1234)
let remoteEndpoint = Endpoint(address: IPv4Address(SwiftNetworkMultiplexingTests.localIPv4Address)!, port: 2345)

var instance: TestMultiplexingProtocol? = nil
var upperHarness1: DatagramUpperHarness?
Expand Down Expand Up @@ -217,8 +221,8 @@ final class SwiftNetworkMultiplexingTests: NetTestCase {
let context = parameters.context
let path = PathProperties(parameters: parameters)

let localEndpoint = Endpoint(address: IPv4Address(SwiftNetworkUDPTests.localIPv4Address)!, port: 1234)
let remoteEndpoint = Endpoint(address: IPv4Address(SwiftNetworkUDPTests.localIPv4Address)!, port: 2345)
let localEndpoint = Endpoint(address: IPv4Address(SwiftNetworkMultiplexingTests.localIPv4Address)!, port: 1234)
let remoteEndpoint = Endpoint(address: IPv4Address(SwiftNetworkMultiplexingTests.localIPv4Address)!, port: 2345)

// Use a high number of streams to ensure that we don't have poor scaling
let upperHarnessCount = 1000
Expand Down
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