Minimal working parallel ping implementation

modules/low-level/multithreading/build.gradle.kts

@@ -25,6 +25,7 @@ kotlin {
 		commonMain {
 			dependencies {
 				implementation(Dependencies.kotlin_atomicfu)
+				implementation(project(":modules:utilities"))
 			}
 		}
 

modules/low-level/multithreading/src/commonMain/kotlin/ru/landgrafhomyak/bgtu/networks0/low_level/multithreading/CountDownLatch.kt

@@ -1,13 +1,17 @@
 package ru.landgrafhomyak.bgtu.networks0.low_level.multithreading
 
+import ru.landgrafhomyak.bgtu.networks0.utilities.CloseableRefCounter
+import ru.landgrafhomyak.bgtu.networks0.utilities._safeAutoClose1
+import ru.landgrafhomyak.bgtu.networks0.utilities._safeAutoClose2
+
 class CountDownLatch : AutoCloseable {
-	private val _refcnt: _Refcnt
+	private val _refcnt: CloseableRefCounter
 	private var _counter: ULong
 	private val _mutex: Mutex
 	private val _condition: Condition
 
 	constructor(initialCounterValue: ULong) {
-		this._refcnt = _Refcnt("Latch was destroyed")
+		this._refcnt = CloseableRefCounter("Latch was destroyed")
 		this._counter = initialCounterValue
 		this._mutex = Mutex()
 		_safeAutoClose2(onAbort = this._mutex::close) {

modules/low-level/multithreading/src/commonMain/kotlin/ru/landgrafhomyak/bgtu/networks0/low_level/multithreading/extensions.kt

@@ -3,6 +3,7 @@ package ru.landgrafhomyak.bgtu.networks0.low_level.multithreading
 import kotlin.contracts.ExperimentalContracts
 import kotlin.contracts.InvocationKind
 import kotlin.contracts.contract
+import ru.landgrafhomyak.bgtu.networks0.utilities._safeAutoClose1
 
 @OptIn(ExperimentalContracts::class)
 inline fun <R> Mutex.withLock(synchronizedBlock: () -> R): R {

modules/low-level/multithreading/src/posixMain/kotlin/ru/landgrafhomyak/bgtu/networks0/low_level/multithreading/Condition.kt

@@ -13,15 +13,18 @@ import platform.posix.pthread_cond_wait
 import platform.posix.pthread_cond_broadcast
 import platform.posix.pthread_cond_signal
 import ru.landgrafhomyak.bgtu.networks0.low_level.c_interop_utilities.PosixUtilities
+import ru.landgrafhomyak.bgtu.networks0.utilities.CloseableRefCounter
+import ru.landgrafhomyak.bgtu.networks0.utilities._safeAutoClose1
+import ru.landgrafhomyak.bgtu.networks0.utilities._safeAutoClose2
 
 
 @OptIn(ExperimentalForeignApi::class)
 actual class Condition : AutoCloseable {
-	private val _refcnt: _Refcnt
+	private val _refcnt: CloseableRefCounter
 	val _descriptor: CPointer<pthread_cond_t>
 
 	actual constructor() {
-		this._refcnt = _Refcnt("Pthreads condition was destroyed")
+		this._refcnt = CloseableRefCounter("Pthreads condition was destroyed")
 		this._descriptor = nativeHeap.alloc<pthread_cond_t>().ptr
 		_safeAutoClose2(onAbort = { nativeHeap.free(this._descriptor) }) {
 			var err = pthread_cond_init(this._descriptor, null)

modules/low-level/multithreading/src/posixMain/kotlin/ru/landgrafhomyak/bgtu/networks0/low_level/multithreading/Mutex.kt

@@ -12,6 +12,9 @@ import platform.posix.pthread_mutex_lock
 import platform.posix.pthread_mutex_t
 import platform.posix.pthread_mutex_unlock
 import ru.landgrafhomyak.bgtu.networks0.low_level.c_interop_utilities.PosixUtilities
+import ru.landgrafhomyak.bgtu.networks0.utilities.CloseableRefCounter
+import ru.landgrafhomyak.bgtu.networks0.utilities._safeAutoClose1
+import ru.landgrafhomyak.bgtu.networks0.utilities._safeAutoClose2
 
 @OptIn(ExperimentalForeignApi::class, Mutex.RefcntAccess::class)
 actual class Mutex : AutoCloseable {
@@ -19,11 +22,11 @@ actual class Mutex : AutoCloseable {
 	internal annotation class RefcntAccess
 
 	@RefcntAccess
-	internal val _refcnt: _Refcnt
+	internal val _refcnt: CloseableRefCounter
 	internal val _descriptor: CPointer<pthread_mutex_t>
 
 	actual constructor() {
-		this._refcnt = _Refcnt("Pthreads mutex was destroyed")
+		this._refcnt = CloseableRefCounter("Pthreads mutex was destroyed")
 		this._descriptor = nativeHeap.alloc<pthread_mutex_t>().ptr
 		_safeAutoClose2(onAbort = { nativeHeap.free(this._descriptor) }) {
 			var err = pthread_mutex_init(this._descriptor, null)

modules/low-level/multithreading/src/posixMain/kotlin/ru/landgrafhomyak/bgtu/networks0/low_level/multithreading/Thread.kt

@@ -9,6 +9,10 @@ import kotlinx.cinterop.StableRef
 import kotlinx.cinterop.asStableRef
 import kotlinx.cinterop.staticCFunction
 import ru.landgrafhomyak.bgtu.networks0.low_level.c_interop_utilities.PosixUtilities
+import ru.landgrafhomyak.bgtu.networks0.utilities._safeAutoClose1
+import ru.landgrafhomyak.bgtu.networks0.utilities._safeAutoClose2
+import ru.landgrafhomyak.bgtu.networks0.utilities._safeAutoClose2e
+import ru.landgrafhomyak.bgtu.networks0.utilities.compareAndExchange
 
 @OptIn(ExperimentalForeignApi::class)
 actual class Thread : AutoCloseable {

modules/low-level/sockets/build.gradle.kts

@@ -1,4 +1,5 @@
 import ru.landgrafhomyak.bgtu.networks0.build_script.Dependencies
+import ru.landgrafhomyak.bgtu.networks0.build_script.configureWarnings
 import ru.landgrafhomyak.bgtu.networks0.build_script.setupHierarchy
 
 plugins {
@@ -11,6 +12,8 @@ repositories {
 
 
 kotlin {
+	configureWarnings()
+
 	mingwX64()
 	linuxX64()
 	linuxArm64()
@@ -22,13 +25,14 @@ kotlin {
 		commonMain {
 			dependencies {
 				implementation(Dependencies.kotlin_atomicfu)
+				implementation(Dependencies.kotlin_coroutines_core)
+				implementation(project(":modules:low-level:multithreading"))
 			}
 		}
 
 		nativeMain {
 			dependencies {
 				implementation(project(":modules:low-level:c-interop-utilities"))
-				implementation(project(":modules:low-level:multithreading"))
 			}
 		}
 	}

modules/low-level/sockets/src/commonMain/kotlin/ru/landgrafhomyak/bgtu/networks0/low_level/sockets/IcmpSocket.kt

@@ -1,6 +1,23 @@
 package ru.landgrafhomyak.bgtu.networks0.low_level.sockets
 
+/**
+ * High-level interface for interacting with icmp socket.
+ * Destination host address is bound to instance and can't be changed.
+ */
 interface IcmpSocket : AutoCloseable {
-	suspend fun send(data: UByteArray)
-	suspend fun recv(): UByteArray
+	/**
+	 * Sends [data] as is in single datagram to destination host.
+	 */
+	suspend fun sendRaw(data: UByteArray)
+
+	/**
+	 * Waits for datagram from destination host and returns it as is.
+	 */
+	suspend fun recvRaw(): UByteArray
+
+	/**
+	 * Closes socket and releases related resources.
+	 * @throws IllegalStateException if called on already closed socket.
+	 */
+	override fun close()
 }

modules/low-level/sockets/src/commonMain/kotlin/ru/landgrafhomyak/bgtu/networks0/low_level/sockets/SocketBlockingEventLoop.kt

@@ -1,9 +0,0 @@
-package ru.landgrafhomyak.bgtu.networks0.low_level.sockets
-
-expect class SocketBlockingEventLoop : ru.landgrafhomyak.bgtu.networks0.low_level.sockets.SocketEventLoop {
-	public constructor()
-
-	companion object {
-		fun runForever(el: ru.landgrafhomyak.bgtu.networks0.low_level.sockets.SocketBlockingEventLoop)
-	}
-}

modules/low-level/sockets/src/commonMain/kotlin/ru/landgrafhomyak/bgtu/networks0/low_level/sockets/SocketEventLoop.kt

@@ -1,7 +0,0 @@
-package ru.landgrafhomyak.bgtu.networks0.low_level.sockets
-
-@Suppress("FunctionName")
-interface SocketEventLoop {
-	fun icmp_IPv4(addr: String): ru.landgrafhomyak.bgtu.networks0.low_level.sockets.IcmpSocket
-	fun icmp_IPv6(addr: String): ru.landgrafhomyak.bgtu.networks0.low_level.sockets.IcmpSocket
-}

modules/low-level/sockets/src/commonMain/kotlin/ru/landgrafhomyak/bgtu/networks0/low_level/sockets/SocketEventLoopScope.kt

@@ -0,0 +1,27 @@
+package ru.landgrafhomyak.bgtu.networks0.low_level.sockets
+
+/**
+ * User-side interface of socket event-loops.
+ */
+@Suppress("FunctionName")
+interface SocketEventLoopScope {
+	/**
+	 * Creates [ICMP socket][IcmpSocket] bound with specified [address][addr] to communicate over IPv4.
+	 */
+	fun icmp_IPv4(addr: String): IcmpSocket
+
+	/**
+	 * Creates [ICMP socket][IcmpSocket] bound with specified [address][addr] to communicate over IPv6.
+	 */
+	fun icmp_IPv6(addr: String): IcmpSocket
+
+	interface Closeable : SocketEventLoopScope, AutoCloseable {
+		/**
+		 * Closes event-loop and releases related resources.
+		 *
+		 * @throws IllegalStateException if there are unclosed sockets bound to this event-loop.
+		 * @throws IllegalStateException if called on already closed socket.
+		 */
+		override fun close()
+	}
+}

modules/low-level/sockets/src/commonMain/kotlin/ru/landgrafhomyak/bgtu/networks0/low_level/sockets/utility/CloseGuardEventLoop.kt

@@ -0,0 +1,67 @@
+package ru.landgrafhomyak.bgtu.networks0.low_level.sockets.utility
+
+import kotlinx.atomicfu.atomic
+import kotlinx.atomicfu.update
+import ru.landgrafhomyak.bgtu.networks0.low_level.sockets.IcmpSocket
+import ru.landgrafhomyak.bgtu.networks0.low_level.sockets.SocketEventLoopScope
+
+@Suppress("FunctionName", "MemberVisibilityCanBePrivate", "PropertyName")
+class CloseGuardEventLoop<T : SocketEventLoopScope.Closeable>(
+	val _unprotected: T,
+) : SocketEventLoopScope.Closeable {
+
+	private var _isClosed = atomic(false)
+	private var _openedSockets = atomic(0uL)
+
+	private fun _assertNotClosed() {
+		if (this._isClosed.value) throw IllegalStateException("Event-loop is closed")
+	}
+
+	private fun _incrementOpenedSockets() = this._openedSockets.update { x -> x + 1u }
+	private fun _decrementOpenedSockets() = this._openedSockets.update { x -> x - 1u }
+
+	override fun icmp_IPv4(addr: String): IcmpSocket {
+		this._assertNotClosed()
+		this._incrementOpenedSockets()
+		return ProtectedIcmpSocket(this._unprotected.icmp_IPv4(addr))
+	}
+
+	override fun icmp_IPv6(addr: String): IcmpSocket {
+		this._assertNotClosed()
+		this._incrementOpenedSockets()
+		return ProtectedIcmpSocket(this._unprotected.icmp_IPv6(addr))
+	}
+
+	override fun close() {
+		this._assertNotClosed()
+		if (this._openedSockets.value > 0uL)
+			throw IllegalStateException("There are still opened sockets, close them manually first")
+		this._unprotected.close()
+	}
+
+	private inner class ProtectedIcmpSocket(private val _unprotected: IcmpSocket) : IcmpSocket {
+		private val _isClosed = atomic(false)
+
+		private fun _assertNotClosed() {
+			if (this._isClosed.value) throw IllegalStateException("Socket is closed")
+		}
+
+		override suspend fun sendRaw(data: UByteArray) {
+			this._assertNotClosed()
+			this._unprotected.sendRaw(data)
+		}
+
+		override suspend fun recvRaw(): UByteArray {
+			this._assertNotClosed()
+			return this._unprotected.recvRaw()
+		}
+
+		override fun close() {
+			if (this._isClosed.getAndSet(true))
+				throw IllegalStateException("Socket is closed")
+			this._unprotected.close()
+			this@CloseGuardEventLoop._decrementOpenedSockets()
+		}
+
+	}
+}

modules/low-level/sockets/src/linuxMain/kotlin/ru/landgrafhomyak/bgtu/networks0/low_level/sockets/EpollSocketEventLoop.kt

@@ -0,0 +1,198 @@
+package ru.landgrafhomyak.bgtu.networks0.low_level.sockets
+
+import kotlin.coroutines.Continuation
+import kotlin.coroutines.resume
+import kotlin.coroutines.suspendCoroutine
+import kotlinx.cinterop.CValue
+import kotlinx.cinterop.ExperimentalForeignApi
+import kotlinx.cinterop.StableRef
+import kotlinx.cinterop.allocArray
+import kotlinx.cinterop.asStableRef
+import kotlinx.cinterop.cValue
+import kotlinx.cinterop.get
+import kotlinx.cinterop.memScoped
+import kotlinx.cinterop.ptr
+import platform.linux.EPOLLIN
+import platform.linux.EPOLLONESHOT
+import platform.linux.EPOLLOUT
+import platform.linux.EPOLL_CTL_ADD
+import platform.linux.EPOLL_CTL_MOD
+import platform.linux.epoll_create
+import platform.linux.epoll_ctl
+import platform.linux.epoll_event
+import platform.linux.epoll_wait
+import platform.linux.inet_pton
+import platform.posix.AF_INET
+import platform.posix.sockaddr_in
+import platform.posix.sockaddr_in6
+import ru.landgrafhomyak.bgtu.networks0.low_level.c_interop_utilities.PosixUtilities
+import ru.landgrafhomyak.bgtu.networks0.low_level.multithreading.Mutex as TMutex
+import ru.landgrafhomyak.bgtu.networks0.low_level.multithreading.withLock
+import ru.landgrafhomyak.bgtu.networks0.utilities._safeAutoClose1
+import ru.landgrafhomyak.bgtu.networks0.utilities._safeAutoClose2
+
+@OptIn(ExperimentalForeignApi::class)
+@Suppress("JoinDeclarationAndAssignment", "ConvertSecondaryConstructorToPrimary", "FunctionName")
+class EpollSocketEventLoop : SocketEventLoopScope.Closeable {
+	private val _epollDescriptor: Int
+
+	constructor() {
+		this._epollDescriptor = epoll_create(1)
+		if (this._epollDescriptor < 0)
+			PosixUtilities.throwErrno { d -> RuntimeException("Failed to create epoll descriptor: $d") }
+	}
+
+	private fun _parseIpv4(rawAddr: String, port: UShort): CValue<sockaddr_in> = cValue<sockaddr_in> out@{
+		memScoped<Unit> {
+			val err = inet_pton(AF_INET, rawAddr, this@out.sin_addr.ptr)
+			when {
+				err == 0 -> throw IllegalArgumentException("IPv4 address is ill-formatted")
+				err < 0 -> PosixUtilities.throwErrno { d -> throw RuntimeException("Failed to parse IPv4 address: $d") }
+			}
+		}
+		this@out.sin_family = AF_INET.toUShort()
+		this@out.sin_port = port
+	}
+
+	override fun icmp_IPv4(addr: String): IcmpSocket {
+		return BoundIcmpSocket(this._parseIpv4(addr, 0u))
+	}
+
+	override fun icmp_IPv6(addr: String): IcmpSocket {
+		TODO("Not yet implemented")
+	}
+
+	private fun _waitFor(metadata: _SocketMetadata) {
+		val ee = cValue<epoll_event> {
+			this.events = ((if (metadata.read == null) 0 else EPOLLIN) or (if (metadata.write == null) 0 else EPOLLOUT) or EPOLLONESHOT).toUInt()
+			this.data.fd = metadata.fd
+			this.data.ptr = metadata.stableRef.asCPointer()
+		}
+		if (!metadata.isAddedToEpoll) {
+			if (0 != epoll_ctl(this._epollDescriptor, EPOLL_CTL_ADD, metadata.fd, ee))
+				PosixUtilities.throwErrno { d -> RuntimeException("Failed to add fd to epoll: $d") }
+			metadata.isAddedToEpoll = true
+		} else {
+			if (0 != epoll_ctl(this._epollDescriptor, EPOLL_CTL_MOD, metadata.fd, ee))
+				PosixUtilities.throwErrno { d -> RuntimeException("Failed to modify fd in epoll: $d") }
+		}
+	}
+
+	private suspend fun _waitForRead(metadata: _SocketMetadata) = suspendCoroutine { continuation ->
+		metadata.sync.withLock {
+			if (metadata.read != null)
+				throw IllegalStateException("Socket already waiting for read")
+			metadata.read = continuation
+			this._waitFor(metadata)
+		}
+	}
+
+
+	private suspend fun _waitForWrite(metadata: _SocketMetadata) = suspendCoroutine { continuation ->
+		metadata.sync.withLock {
+			if (metadata.write != null)
+				throw IllegalStateException("Socket already waiting for write")
+			metadata.write = continuation
+			this._waitFor(metadata)
+		}
+	}
+
+	private fun _resume(ev: epoll_event) {
+		val metadata = (ev.data.ptr ?: throw RuntimeException("Lost reference to socket metadata")).asStableRef<_SocketMetadata>().get()
+		metadata.sync.withLock {
+			if ((ev.events and EPOLLIN.toUInt()) != 0u) {
+				(metadata.read ?: throw RuntimeException("Socket ready for read, but nobody requests")).resume(Unit)
+				metadata.read = null
+			}
+			if ((ev.events and EPOLLOUT.toUInt()) != 0u) {
+				(metadata.write ?: throw RuntimeException("Socket ready for read, but nobody requests")).resume(Unit)
+				metadata.write = null
+			}
+			if (metadata.read != null || metadata.write != null)
+				this._waitFor(metadata)
+		}
+	}
+
+	fun runUntilError(eventsBufferSize: Int = 1000) {
+		memScoped {
+			val readyEvents = allocArray<epoll_event>(eventsBufferSize)
+			while (true) {
+				val readyEventsCount = epoll_wait(this@EpollSocketEventLoop._epollDescriptor, readyEvents, eventsBufferSize, -1)
+				if (readyEventsCount < 0)
+					PosixUtilities.throwErrno { d -> RuntimeException("Error while waiting epoll: $d") }
+
+				for (i in 0..<readyEventsCount) {
+					this@EpollSocketEventLoop._resume(readyEvents[i])
+				}
+			}
+		}
+	}
+
+
+	override fun close() {
+		TODO("Not yet implemented")
+	}
+
+	class _SocketMetadata : AutoCloseable {
+		val fd: Int
+		var read: Continuation<Unit>?
+		var write: Continuation<Unit>?
+		val sync: TMutex
+		val stableRef: StableRef<_SocketMetadata>
+		var isAddedToEpoll: Boolean
+
+		constructor(fd: Int) {
+			this.isAddedToEpoll = false
+			this.fd = fd
+			this.read = null
+			this.write = null
+			this.stableRef = StableRef.create(this)
+			_safeAutoClose2(onAbort = this.stableRef::dispose) {
+				this.sync = TMutex()
+			}
+		}
+
+		override fun close() {
+			_safeAutoClose1(
+				action = this.sync::close,
+				finally = this.stableRef::dispose
+			)
+		}
+	}
+
+
+	private inner class BoundIcmpSocket : NonblockingIcmpSocketImpl {
+		private val __metadata: _SocketMetadata
+
+		constructor(ipv4: CValue<sockaddr_in>) : super(ipv4) {
+			_safeAutoClose2(onAbort = { super.close() }) {
+				this.__metadata = _SocketMetadata(this._socketFd)
+			}
+		}
+
+		constructor(ipv6: CValue<sockaddr_in6>) : super(ipv6) {
+			_safeAutoClose2(onAbort = { super.close() }) {
+				this.__metadata = _SocketMetadata(this._socketFd)
+			}
+		}
+
+
+		override suspend fun _waitForWrite() =
+			this@EpollSocketEventLoop._waitForWrite(this.__metadata)
+
+		override suspend fun _waitForRead() =
+			this@EpollSocketEventLoop._waitForRead(this.__metadata)
+
+		override fun close() {
+			_safeAutoClose1(
+				action = {},
+				finally = {
+					_safeAutoClose1(
+						action = this.__metadata::close,
+						finally = { super.close() }
+					)
+				}
+			)
+		}
+	}
+}

modules/low-level/sockets/src/linuxMain/kotlin/ru/landgrafhomyak/bgtu/networks0/low_level/sockets/SocketBlockingEventLoop.kt

@@ -1,158 +0,0 @@
-package ru.landgrafhomyak.bgtu.networks0.low_level.sockets
-
-import kotlin.concurrent.AtomicReference
-import kotlin.coroutines.Continuation
-import kotlin.coroutines.resume
-import kotlin.coroutines.suspendCoroutine
-import kotlinx.atomicfu.atomic
-import kotlinx.cinterop.CValue
-import kotlinx.cinterop.ExperimentalForeignApi
-import kotlinx.cinterop.allocArray
-import kotlinx.cinterop.cValue
-import kotlinx.cinterop.get
-import kotlinx.cinterop.memScoped
-import kotlinx.cinterop.ptr
-import platform.linux.EPOLLIN
-import platform.linux.EPOLLOUT
-import platform.linux.EPOLL_CTL_ADD
-import platform.linux.epoll_create
-import platform.linux.epoll_ctl
-import platform.linux.epoll_event
-import platform.linux.epoll_wait
-import platform.linux.inet_pton
-import platform.posix.AF_INET
-import platform.posix.sockaddr_in
-import platform.posix.sockaddr_in6
-import ru.landgrafhomyak.bgtu.networks0.low_level.c_interop_utilities.PosixUtilities
-import ru.landgrafhomyak.bgtu.networks0.low_level.multithreading.TMutex
-import ru.landgrafhomyak.bgtu.networks0.low_level.multithreading.withLock
-
-@OptIn(ExperimentalForeignApi::class)
-@Suppress("JoinDeclarationAndAssignment", "ConvertSecondaryConstructorToPrimary", "FunctionName")
-actual class SocketBlockingEventLoop : SocketEventLoop {
-	private val _tsync = TMutex()
-	private val _id2cont = HashMap<ULong, Continuation<Unit>>()
-	private var _nextSockId: ULong = 0uL
-	private val _epollDescriptor: Int
-
-	actual constructor() {
-		this._epollDescriptor = epoll_create(0)
-		if (this._epollDescriptor < 0)
-			PosixUtilities.throwErrno { d -> RuntimeException("Failed to create epoll descriptor: $d") }
-	}
-
-
-	private val _state = AtomicReference(State.READY)
-	private val _openedSockets = atomic(0uL)
-
-	private enum class State {
-		READY, RUNNING, CLOSED
-	}
-
-	private fun _assertNotClosed() {
-		if (this._state.value == State.CLOSED)
-			throw IllegalStateException("Eventloop is closed")
-	}
-
-
-	private fun _parseIpv4(rawAddr: String, port: UShort): CValue<sockaddr_in> = cValue<sockaddr_in> out@{
-		memScoped<Unit> {
-			val err = inet_pton(AF_INET, rawAddr, this@out.sin_addr.ptr)
-			when {
-				err == 0 -> throw IllegalArgumentException("IPv4 address is ill-formatted")
-				err < 0 -> PosixUtilities.throwErrno { d -> throw RuntimeException("Failed to parse IPv4 address: $d") }
-			}
-		}
-		this@out.sin_family = AF_INET.toUShort()
-		this@out.sin_port = port
-	}
-
-
-	override fun icmp_IPv4(addr: String): IcmpSocket {
-		this._assertNotClosed()
-		return BoundIcmpSocket(this._parseIpv4(addr, 0u))
-	}
-
-	override fun icmp_IPv6(addr: String): IcmpSocket {
-		this._assertNotClosed()
-		TODO("Not yet implemented")
-	}
-
-	private suspend fun _waitFor(fd: Int, action: Int) = suspendCoroutine { continuation ->
-		val contId: ULong
-		this._tsync.withLock {
-			contId = this._nextSockId++
-			this._id2cont[contId] = continuation
-		}
-
-		val ee = cValue<epoll_event> {
-			this.events = action.toUInt()
-			this.data.fd = fd
-			this.data.u64 = contId
-		}
-
-		if (0 != epoll_ctl(this._epollDescriptor, EPOLL_CTL_ADD, fd, ee))
-			PosixUtilities.throwErrno { d -> RuntimeException("Failed to add event to epoll: $d") }
-	}
-
-	private suspend fun _waitForRead(fd: Int) =
-		this._waitFor(fd, EPOLLIN)
-
-
-	private suspend fun _waitForWrite(fd: Int) =
-		this._waitFor(fd, EPOLLOUT)
-
-	private fun _resume(id: ULong) {
-		val cont = this._tsync.withLock { this._id2cont.remove(id) }
-		if (cont == null) {
-			// todo
-			return
-		}
-		cont.resume(Unit)
-	}
-
-	private fun _mainloop() {
-		when (this._state.compareAndExchange(State.READY, State.RUNNING)) {
-			State.RUNNING -> throw IllegalStateException("Eventloop already running")
-			State.CLOSED -> throw IllegalStateException("Eventloop is closed")
-			State.READY -> {}
-		}
-
-		val eventsBufferSize = 100
-		memScoped {
-			val readyEvents = allocArray<epoll_event>(eventsBufferSize)
-			while (true) {
-				val readyEventsCount = epoll_wait(this@SocketBlockingEventLoop._epollDescriptor, readyEvents, eventsBufferSize, -1)
-				if (readyEventsCount < 0)
-					PosixUtilities.throwErrno { d -> RuntimeException("Error while waiting epoll: $d") }
-
-				for (i in 0..<readyEventsCount) {
-					this@SocketBlockingEventLoop._resume(readyEvents[0].data.u64)
-				}
-			}
-		}
-	}
-
-	actual companion object {
-		actual fun runForever(el: SocketBlockingEventLoop) {
-			el._mainloop()
-		}
-	}
-
-	private inner class BoundIcmpSocket : NonblockingIcmpSocketImpl {
-		constructor(ipv4: CValue<sockaddr_in>) : super(ipv4)
-
-		constructor(ipv6: CValue<sockaddr_in6>) : super(ipv6)
-
-		override suspend fun _waitForWrite() =
-			this@SocketBlockingEventLoop._waitForWrite(this._socketFd)
-
-		override suspend fun _waitForRead() =
-			this@SocketBlockingEventLoop._waitForRead(this._socketFd)
-
-		override fun close() {
-			TODO("Not yet implemented")
-		}
-
-	}
-}

modules/low-level/sockets/src/posixMain/kotlin/ru/landgrafhomyak/bgtu/networks0/low_level/sockets/NonblockingIcmpSocketImpl.kt

@@ -1,14 +1,18 @@
 package ru.landgrafhomyak.bgtu.networks0.low_level.sockets
 
+import kotlinx.atomicfu.locks.MutexPool
 import kotlinx.cinterop.CValue
 import kotlinx.cinterop.ExperimentalForeignApi
 import kotlinx.cinterop.addressOf
 import kotlinx.cinterop.memScoped
 import kotlinx.cinterop.usePinned
+import kotlinx.coroutines.sync.Mutex as CMutex
+import kotlinx.coroutines.sync.withLock
 import platform.posix.AF_INET
 import platform.posix.AF_INET6
 import platform.posix.EAGAIN
 import platform.posix.EMSGSIZE
+import platform.posix.EPERM
 import platform.posix.EWOULDBLOCK
 import platform.posix.F_SETFL
 import platform.posix.IPPROTO_ICMP
@@ -31,32 +35,37 @@ import platform.posix.recv as recv_lowlevel
 import ru.landgrafhomyak.bgtu.networks0.low_level.c_interop_utilities.CUtilities
 import ru.landgrafhomyak.bgtu.networks0.low_level.c_interop_utilities.PosixUtilities
 
-@Suppress("CanBeVal", "DUPLICATE_LABEL_IN_WHEN")
+@Suppress("CanBeVal")
 @OptIn(ExperimentalForeignApi::class)
 internal abstract class NonblockingIcmpSocketImpl : IcmpSocket {
 	protected val _socketFd: Int
+	private val _rSync = CMutex()
+	private val _wSync = CMutex()
 
 	protected constructor(ipv4: CValue<sockaddr_in>) {
-		this._socketFd = this.__createSocket(AF_INET, IPPROTO_ICMP, ipv4, CUtilities.sizeOfUI<sockaddr_in>())
+		this._socketFd = this.__createSocket(AF_INET, IPPROTO_ICMP, ipv4, CUtilities.sizeOfUI<sockaddr_in>(), "IPv4")
 	}
 
 	protected constructor(ipv6: CValue<sockaddr_in6>) {
-		this._socketFd = this.__createSocket(AF_INET6, IPPROTO_ICMPV6, ipv6, CUtilities.sizeOfUI<sockaddr_in6>())
+		this._socketFd = this.__createSocket(AF_INET6, IPPROTO_ICMPV6, ipv6, CUtilities.sizeOfUI<sockaddr_in6>(), "IPv6")
 	}
 
 	@Suppress("FunctionName")
-	private fun __createSocket(addrFamily: Int, protocol: Int, addrValue: CValue<*>, addrSize: UInt): Int {
+	private fun __createSocket(addrFamily: Int, protocol: Int, addrValue: CValue<*>, addrSize: UInt, protoName: String): Int {
 		val sock = socket(addrFamily, SOCK_RAW, protocol)
-		if (sock < 0)
-			PosixUtilities.throwErrno { d -> RuntimeException("Failed to create ICMP socket over IPv4: $d") }
-
+		if (sock < 0) {
+			if (errno == EPERM)
+				PosixUtilities.throwErrno { d -> RuntimeException("Failed to create ICMP socket over ${protoName}: $d (maybe you need to run this program as superuser)") }
+			else
+				PosixUtilities.throwErrno { d -> RuntimeException("Failed to create ICMP socket over ${protoName}: $d") }
+		}
 
 		var err = memScoped {
 			@Suppress("UNCHECKED_CAST")
 			return@memScoped connect(sock, addrValue as CValue<sockaddr>, addrSize)
 		}
 		if (err != 0)
-			PosixUtilities.throwErrno { d -> RuntimeException("Failed to bind ICMP socket to provided IPv6 address: $d") }
+			PosixUtilities.throwErrno { d -> RuntimeException("Failed to bind ICMP socket to provided $protoName address: $d") }
 
 		err = fcntl(sock, F_SETFL, O_NONBLOCK)
 		if (err != 0)
@@ -72,23 +81,25 @@ internal abstract class NonblockingIcmpSocketImpl : IcmpSocket {
 	@Suppress("FunctionName")
 	protected abstract suspend fun _waitForRead()
 
-	override suspend fun send(data: UByteArray) {
+	override suspend fun sendRaw(data: UByteArray) = this._wSync.withLock {
 		polling@ while (true) {
 			this._waitForWrite()
 			val sentCount = data.usePinned { pinnedData ->
 				return@usePinned send_lowlevel(this._socketFd, pinnedData.addressOf(0), data.size.toULong(), MSG_NOSIGNAL)
 			}
+			val err = errno
 			if (sentCount < 0) {
-				when (errno) {
+				when (err) {
 					EAGAIN, EWOULDBLOCK -> continue@polling
 					EMSGSIZE -> throw IllegalArgumentException("Data size bigger than can be sent by one packet")
-					else -> PosixUtilities.throwErrno { d -> RuntimeException("Failed to send message ove ICMP socket: $d") }
+					else -> PosixUtilities.throwErrno(err) { d -> RuntimeException("Failed to send message ove ICMP socket: $d") }
 				}
 			}
+			return
 		}
 	}
 
-	override suspend fun recv(): UByteArray {
+	override suspend fun recvRaw(): UByteArray = this._rSync.withLock {
 		polling@ while (true) {
 			this._waitForRead()
 			val bytesAvailable: ssize_t = recv_lowlevel(
@@ -99,7 +110,7 @@ internal abstract class NonblockingIcmpSocketImpl : IcmpSocket {
 			if (bytesAvailable < 0) {
 				when (errno) {
 					EAGAIN, EWOULDBLOCK -> continue@polling
-					else -> PosixUtilities.throwErrno { d -> RuntimeException("Failed to send message ove ICMP socket: $d") }
+					else -> PosixUtilities.throwErrno { d -> RuntimeException("Failed to send message over ICMP socket: $d") }
 				}
 			}
 
@@ -110,9 +121,15 @@ internal abstract class NonblockingIcmpSocketImpl : IcmpSocket {
 			if (sentCount < 0) {
 				when (errno) {
 					EAGAIN, EWOULDBLOCK -> continue@polling
-					else -> PosixUtilities.throwErrno { d -> RuntimeException("Failed to send message ove ICMP socket: $d") }
-				}
+					else -> PosixUtilities.throwErrno { d -> RuntimeException("Failed to send message over ICMP socket: $d") }
 				}
 			}
+			return@withLock data
+		}
+		return@withLock ubyteArrayOf()
+	}
+
+	override fun close() {
+
 	}
 }

modules/utilities/build.gradle.kts

@@ -0,0 +1,28 @@
+import ru.landgrafhomyak.bgtu.networks0.build_script.Dependencies
+import ru.landgrafhomyak.bgtu.networks0.build_script.configureWarnings
+import ru.landgrafhomyak.bgtu.networks0.build_script.setupHierarchy
+import ru.landgrafhomyak.kotlin.kmp_gradle_build_helper.defineAllMultiplatformTargets
+
+plugins {
+	kotlin("multiplatform")
+}
+
+repositories {
+	mavenCentral()
+}
+
+
+kotlin {
+	configureWarnings()
+
+	defineAllMultiplatformTargets()
+	sourceSets {
+		setupHierarchy()
+
+		commonMain {
+			dependencies {
+				implementation(Dependencies.kotlin_atomicfu)
+			}
+		}
+	}
+}

modules/utilities/src/commonMain/kotlin/ru/landgrafhomyak/bgtu/networks0/utilities/CloseableRefCounter.kt

@@ -1,10 +1,10 @@
-package ru.landgrafhomyak.bgtu.networks0.low_level.multithreading
+package ru.landgrafhomyak.bgtu.networks0.utilities
 
 import kotlinx.atomicfu.AtomicLong
 import kotlinx.atomicfu.atomic
 import kotlinx.atomicfu.update
 
-internal class _Refcnt(private val _errMessage: String) {
+class CloseableRefCounter(private val _errMessage: String) {
 	private val _value: AtomicLong = atomic(0L)
 
 	fun throwClosed() {

modules/utilities/src/commonMain/kotlin/ru/landgrafhomyak/bgtu/networks0/utilities/atomics.kt

@@ -0,0 +1,20 @@
+package ru.landgrafhomyak.bgtu.networks0.utilities
+
+import kotlinx.atomicfu.AtomicLong
+import kotlinx.atomicfu.AtomicRef
+
+fun AtomicLong.compareAndExchange(expected: Long, newValue: Long): Long {
+	while (true) {
+		val old = this.value
+		if (old != expected) return old
+		if (this.compareAndSet(old, newValue)) return old
+	}
+}
+
+fun <T> AtomicRef<T>.compareAndExchange(expected: T, newValue: T): T {
+	while (true) {
+		val old = this.value
+		if (old === expected) return old
+		if (this.compareAndSet(old, newValue)) return old
+	}
+}

modules/utilities/src/commonMain/kotlin/ru/landgrafhomyak/bgtu/networks0/utilities/auto_close.kt

@@ -1,32 +1,13 @@
 @file:OptIn(ExperimentalContracts::class)
 
-package ru.landgrafhomyak.bgtu.networks0.low_level.multithreading
+package ru.landgrafhomyak.bgtu.networks0.utilities
 
 import kotlin.contracts.ExperimentalContracts
 import kotlin.contracts.InvocationKind
 import kotlin.contracts.contract
-import kotlinx.atomicfu.AtomicLong
-import kotlinx.atomicfu.AtomicRef
-
-internal fun AtomicLong.compareAndExchange(expected: Long, newValue: Long): Long {
-	while (true) {
-		val old = this.value
-		if (old != expected) return old
-		if (this.compareAndSet(old, newValue)) return old
-	}
-}
-
-internal fun <T> AtomicRef<T>.compareAndExchange(expected: T, newValue: T): T {
-	while (true) {
-		val old = this.value
-		if (old === expected) return old
-		if (this.compareAndSet(old, newValue)) return old
-	}
-}
 
 @Suppress("WRONG_INVOCATION_KIND")
-@PublishedApi
-internal inline fun <R> _safeAutoClose1(
+inline fun <R> _safeAutoClose1(
 	finally: () -> Unit,
 	action: () -> R
 ): R {
@@ -38,8 +19,7 @@ internal inline fun <R> _safeAutoClose1(
 }
 
 @Suppress("WRONG_INVOCATION_KIND")
-@PublishedApi
-internal inline fun <R> _safeAutoClose2(
+inline fun <R> _safeAutoClose2(
 	onAbort: () -> Unit = {},
 	onSuccess: () -> Unit = {},
 	action: () -> R
@@ -53,8 +33,7 @@ internal inline fun <R> _safeAutoClose2(
 }
 
 @Suppress("WRONG_INVOCATION_KIND")
-@PublishedApi
-internal inline fun <R> _safeAutoClose2e(
+inline fun <R> _safeAutoClose2e(
 	onAbort: (Throwable) -> Unit = { _ -> },
 	onSuccess: () -> Unit = {},
 	action: () -> R
@@ -67,8 +46,7 @@ internal inline fun <R> _safeAutoClose2e(
 	return _safeAutoClose3e(onAbort = onAbort, onSuccess = onSuccess, onCrossReturn = onSuccess, action = action)
 }
 
-@PublishedApi
-internal inline fun <R> _safeAutoClose3(
+inline fun <R> _safeAutoClose3(
 	onAbort: () -> Unit = {},
 	onSuccess: () -> Unit = {},
 	onCrossReturn: () -> Unit = {},
@@ -83,8 +61,7 @@ internal inline fun <R> _safeAutoClose3(
 	return _safeAutoClose3e(onAbort = { t -> onAbort() }, onSuccess = onSuccess, onCrossReturn = onCrossReturn, action = action)
 }
 
-@PublishedApi
-internal inline fun <R> _safeAutoClose3e(
+inline fun <R> _safeAutoClose3e(
 	onAbort: (Throwable) -> Unit = { _ -> },
 	onSuccess: () -> Unit = {},
 	onCrossReturn: () -> Unit = {},

programs/test/build.gradle.kts

@@ -19,6 +19,7 @@ kotlin {
 		linuxX64Main {
 			dependencies {
 				implementation(project(":modules:low-level:multithreading"))
+				implementation(project(":modules:low-level:sockets"))
 			}
 		}
 	}

programs/test/src/linuxX64Main/kotlin/main.kt

@@ -1,41 +1,71 @@
-import platform.posix.sleep
+import kotlinx.coroutines.delay
+import kotlinx.coroutines.launch
+import kotlinx.coroutines.runBlocking
 import ru.landgrafhomyak.bgtu.networks0.low_level.multithreading.Thread
+import ru.landgrafhomyak.bgtu.networks0.low_level.sockets.EpollSocketEventLoop
 
-class Printer(private val prefix: String) : Thread.Routine {
+class EventLoopRoutine(private val loop: EpollSocketEventLoop) : Thread.Routine {
 	override fun run() {
-		for (i in 0..3) {
-			print("${this.prefix}: ${i}\n")
-			sleep(1u)
+		while (true) {
+			try {
+				this.loop.runUntilError()
+			} catch (e: Throwable) {
+				e.printStackTrace()
+				break // todo remove
+			}
 		}
 	}
 }
 
 fun main() {
 	try {
-		println("entry")
+		val loop = EpollSocketEventLoop()
 
-		val t1 = Thread(Printer("t1"))
-		val t2 = Thread(Printer("t2"))
-		val t3 = Thread(Printer("t3"))
-		val t4 = Thread(Printer("t4"))
+		val loopThread = Thread(EventLoopRoutine(loop))
+		loopThread.start()
 
-		println("created")
-		sleep(2u)
-		println("starting...")
+		val googleSock = loop.icmp_IPv4("8.8.8.8")
+		val yandexSock = loop.icmp_IPv4("5.255.255.70")
+		val phoneSock = loop.icmp_IPv4("192.168.43.1")
+		val pingData = ubyteArrayOf(
+			0x08u, 0x00u, 0x4Cu, 0xE4u, 0x00u, 0x01u, 0x00u, 0x77u,
+			0x61u, 0x62u, 0x63u, 0x64u, 0x65u, 0x66u, 0x67u, 0x68u,
+			0x69u, 0x6Au, 0x6Bu, 0x6Cu, 0x6Du, 0x6Eu, 0x6Fu, 0x70u,
+			0x71u, 0x72u, 0x73u, 0x74u, 0x75u, 0x76u, 0x77u, 0x61u,
+			0x62u, 0x63u, 0x64u, 0x65u, 0x66u, 0x67u, 0x68u, 0x69u
+		)
 
-		t1.start()
-		t2.start()
-		t3.start()
-		t4.start()
+		runBlocking {
+			launch {
+				while (true) {
+					googleSock.sendRaw(pingData)
+					print("sent to google\n")
+					googleSock.recvRaw()
+					print("got from google\n")
+					delay(1000)
+				}
+			}
+			launch {
+				while (true) {
+					yandexSock.sendRaw(pingData)
+					print("sent to yandex\n")
+					yandexSock.recvRaw()
+					print("got from yandex\n")
+					delay(2500)
+				}
+			}
+			launch {
+				while (true) {
+					phoneSock.sendRaw(pingData)
+					print("sent to phone\n")
+					phoneSock.recvRaw()
+					print("got from phone\n")
+					delay(5500)
+				}
+			}
+		}
 
-		print("started\n")
 
-		t1.join()?.let(Throwable::printStackTrace)
-		t2.join()?.let(Throwable::printStackTrace)
-		t3.join()?.let(Throwable::printStackTrace)
-		t4.join()?.let(Throwable::printStackTrace)
-
-		println("finished")
 	} catch (e: Throwable) {
 		e.printStackTrace()
 	}

settings.gradle.kts

@@ -21,6 +21,7 @@ pluginManagement {
 		}
 	}
 }
+include(":modules:utilities")
 include(":modules:low-level:c-interop-utilities")
 include(":modules:low-level:multithreading")
 include(":modules:low-level:sockets")