diff options
| -rw-r--r-- | src/main/java/com/it_jaros/jns/scan/engine/ScanUdpPortTask.java | 70 | ||||
| -rw-r--r-- | src/main/java/com/it_jaros/jns/scan/engine/platform/linux/LinuxUdpSocketAPI.java | 32 |
2 files changed, 71 insertions, 31 deletions
diff --git a/src/main/java/com/it_jaros/jns/scan/engine/ScanUdpPortTask.java b/src/main/java/com/it_jaros/jns/scan/engine/ScanUdpPortTask.java index 0c1b9e0..441fd08 100644 --- a/src/main/java/com/it_jaros/jns/scan/engine/ScanUdpPortTask.java +++ b/src/main/java/com/it_jaros/jns/scan/engine/ScanUdpPortTask.java @@ -12,6 +12,8 @@ import java.lang.foreign.MemorySegment; import java.net.InetAddress; import java.util.concurrent.Callable; import java.util.concurrent.Semaphore; +import java.util.concurrent.TimeUnit; +import java.util.concurrent.locks.LockSupport; public class ScanUdpPortTask implements Callable<PortResult> { @@ -23,7 +25,10 @@ public class ScanUdpPortTask implements Callable<PortResult> { private final Scan scan; private final Semaphore socketLimit; private final int port; - private final long timeoutInMillis; + private final long timeoutInNanos; + + private final long waitInMillis = 100; + private final long waitInNanos = TimeUnit.MILLISECONDS.toNanos(waitInMillis); ScanUdpPortTask(int port, ScanExecutionContext context, ScanHostContext hostContext) { this.inetAddress = hostContext.hostAddress(); @@ -32,7 +37,7 @@ public class ScanUdpPortTask implements Callable<PortResult> { this.portScanRateLimiter = hostContext.portScanRateLimiter(); this.scan = context.scan(); this.socketLimit = context.socketLimit(); - this.timeoutInMillis = context.scanOptions().timeoutInMillis(); + this.timeoutInNanos = TimeUnit.MILLISECONDS.toNanos(context.scanOptions().timeoutInMillis()); } @Override @@ -75,31 +80,58 @@ public class ScanUdpPortTask implements Callable<PortResult> { final int family = inetAddress.getAddress().length == 16 ? LinuxUdpSocketAPI.AF_INET6 : LinuxUdpSocketAPI.AF_INET; int fd = linuxUdpSocketAPI.socket(family); try { - linuxUdpSocketAPI.setReceiveTimeout(fd, timeoutInMillis); + linuxUdpSocketAPI.setNonBlocking(fd); linuxUdpSocketAPI.connect(fd, destination); linuxUdpSocketAPI.sendEmptyDatagram(fd); MemorySegment recvBuffer = arena.allocate(RECV_BUFFER_SIZE); - try { - long bytesRead = linuxUdpSocketAPI.recv(fd, recvBuffer); - if (bytesRead >= 0) { - return PortState.OPEN; - } - } catch (RawLinuxSocketException e) { - int errno = e.errno; - if (errno == LinuxUdpSocketAPI.ECONNREFUSED) { - return PortState.CLOSED; - } - if (errno == LinuxUdpSocketAPI.EAGAIN) { - return PortState.FILTERED; - } - throw new IOException("recv() failed: errno=" + errno); - } + return recvUntilDeadline(linuxUdpSocketAPI, fd, recvBuffer); } finally { linuxUdpSocketAPI.close(fd); } } + } - return PortState.UNKNOWN; + /** + * Polls the non-blocking socket until the deadline. + * The native recv() call never blocks, so it cannot pin + * the virtual thread to its carrier thread; the wait between + * polls uses LockSupport.parkNanos, which is safe for virtual threads + */ + private PortState recvUntilDeadline(LinuxUdpSocketAPI socketAPI, int fd, MemorySegment buffer) throws IOException { + final long deadlineNanos = System.nanoTime() + timeoutInNanos; + while (!cancelledToken.isCancelled()) { + final long remainingNanos = deadlineNanos - System.nanoTime(); + if (remainingNanos <= 0) { + break; + } + + long bytesRead; + try { + bytesRead = socketAPI.recv(fd, buffer); + } catch (RawLinuxSocketException e) { + final int errno = e.errno; + if (errno == LinuxUdpSocketAPI.ECONNREFUSED) { + return PortState.CLOSED; + } + if (errno == LinuxUdpSocketAPI.EAGAIN || errno == LinuxUdpSocketAPI.EWOULDBLOCK) { + // no datagram has arrived yet; keep polling + bytesRead = -1; + } else { + throw new IOException("recv() failed: errno=" + errno); + } + } + + if (bytesRead >= 0) { + return PortState.OPEN; + } + + LockSupport.parkNanos(Math.min(waitInNanos, remainingNanos)); + } + + if (cancelledToken.isCancelled()) { + return PortState.UNKNOWN; + } + return PortState.FILTERED; } } diff --git a/src/main/java/com/it_jaros/jns/scan/engine/platform/linux/LinuxUdpSocketAPI.java b/src/main/java/com/it_jaros/jns/scan/engine/platform/linux/LinuxUdpSocketAPI.java index 3f05b67..bfe70d4 100644 --- a/src/main/java/com/it_jaros/jns/scan/engine/platform/linux/LinuxUdpSocketAPI.java +++ b/src/main/java/com/it_jaros/jns/scan/engine/platform/linux/LinuxUdpSocketAPI.java @@ -14,10 +14,12 @@ public class LinuxUdpSocketAPI { public static final int AF_INET = 2; public static final int AF_INET6 = 10; public static final int EAGAIN = 11; + public static final int EWOULDBLOCK = 11; public static final int ECONNREFUSED = 111; public static final int SOCK_DGRAM = 2; - public static final int SOL_SOCKET = 1; - public static final int SO_RCVTIMEO = 20; + public static final int F_GETFL = 3; + public static final int F_SETFL = 4; + public static final int O_NONBLOCK = 2048; private static final Linker LINKER = Linker.nativeLinker(); private static final SymbolLookup LOOKUP = LINKER.defaultLookup(); @@ -79,14 +81,22 @@ public class LinuxUdpSocketAPI { CAPTURE_ERRNO ); - private static final MethodHandle SETSOCKOPT = LINKER.downcallHandle( - LOOKUP.findOrThrow("setsockopt"), + private static final MethodHandle FCTL_GETFL = LINKER.downcallHandle( + LOOKUP.findOrThrow("fcntl"), FunctionDescriptor.of( ValueLayout.JAVA_INT, ValueLayout.JAVA_INT, + ValueLayout.JAVA_INT + ), + CAPTURE_ERRNO + ); + + private static final MethodHandle FCTL_SETFL = LINKER.downcallHandle( + LOOKUP.findOrThrow("fcntl"), + FunctionDescriptor.of( + ValueLayout.JAVA_INT, ValueLayout.JAVA_INT, ValueLayout.JAVA_INT, - ValueLayout.ADDRESS, ValueLayout.JAVA_INT ), CAPTURE_ERRNO @@ -138,6 +148,11 @@ public class LinuxUdpSocketAPI { return this.<Integer>wrapNativeMethodCall(SOCKET, family, SOCK_DGRAM, 0); } + public void setNonBlocking(int fd) throws IOException { + int flags = this.<Integer>wrapNativeMethodCall(FCTL_GETFL, fd, F_GETFL); + wrapNativeMethodCall(FCTL_SETFL, fd, F_SETFL, flags | O_NONBLOCK); + } + public void connect(int fd, MemorySegment destination) throws IOException { wrapNativeMethodCall(CONNECT, fd, destination, (int) destination.byteSize()); } @@ -151,13 +166,6 @@ public class LinuxUdpSocketAPI { return this.<Long>wrapNativeMethodCall(RECV, fd, buffer, buffer.byteSize(), 0); } - public void setReceiveTimeout(int fd, long timeoutInMillis) throws IOException { - MemorySegment timeval = arena.allocate(16); // struct timeval (two longs) - timeval.set(ValueLayout.JAVA_LONG, 0L, timeoutInMillis / 1000L); - timeval.set(ValueLayout.JAVA_LONG, 8L, (timeoutInMillis % 1000L) * 1000L); - wrapNativeMethodCall(SETSOCKOPT, fd, SOL_SOCKET, SO_RCVTIMEO, timeval, 16); - } - public void close(int fd) throws IOException { wrapNativeMethodCall(CLOSE, fd); } |