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1   /*
2    * Copyright 2024 The Netty Project
3    *
4    * The Netty Project licenses this file to you under the Apache License,
5    * version 2.0 (the "License"); you may not use this file except in compliance
6    * with the License. You may obtain a copy of the License at:
7    *
8    *   https://www.apache.org/licenses/LICENSE-2.0
9    *
10   * Unless required by applicable law or agreed to in writing, software
11   * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
12   * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
13   * License for the specific language governing permissions and limitations
14   * under the License.
15   */
16  package io.netty.channel.uring;
17  
18  import io.netty.channel.DefaultFileRegion;
19  import io.netty.channel.unix.Buffer;
20  import io.netty.util.internal.ObjectUtil;
21  import io.netty.util.internal.logging.InternalLogger;
22  import io.netty.util.internal.logging.InternalLoggerFactory;
23  import io.netty.channel.unix.FileDescriptor;
24  import io.netty.channel.unix.PeerCredentials;
25  import io.netty.channel.unix.Unix;
26  import io.netty.util.internal.ClassInitializerUtil;
27  import io.netty.util.internal.NativeLibraryLoader;
28  import io.netty.util.internal.PlatformDependent;
29  import io.netty.util.internal.SystemPropertyUtil;
30  import io.netty.util.internal.ThrowableUtil;
31  
32  import java.io.File;
33  import java.io.IOException;
34  import java.nio.channels.Selector;
35  import java.nio.file.Path;
36  import java.util.Arrays;
37  import java.util.Locale;
38  
39  final class Native {
40      private static final InternalLogger logger = InternalLoggerFactory.getInstance(Native.class);
41      static final int DEFAULT_RING_SIZE = Math.max(64, SystemPropertyUtil.getInt("io.netty.iouring.ringSize", 4096));
42  
43      static {
44          Selector selector = null;
45          try {
46              // We call Selector.open() as this will under the hood cause IOUtil to be loaded.
47              // This is a workaround for a possible classloader deadlock that could happen otherwise:
48              //
49              // See https://github.com/netty/netty/issues/10187
50              selector = Selector.open();
51          } catch (IOException ignore) {
52              // Just ignore
53          }
54  
55          // Preload all classes that will be used in the OnLoad(...) function of JNI to eliminate the possiblity of a
56          // class-loader deadlock. This is a workaround for https://github.com/netty/netty/issues/11209.
57  
58          // This needs to match all the classes that are loaded via NETTY_JNI_UTIL_LOAD_CLASS or looked up via
59          // NETTY_JNI_UTIL_FIND_CLASS.
60          ClassInitializerUtil.tryLoadClasses(
61                  Native.class,
62                  // netty_io_uring_linuxsocket
63                  PeerCredentials.class, java.io.FileDescriptor.class
64          );
65  
66          File tmpDir = PlatformDependent.tmpdir();
67          Path tmpFile = tmpDir.toPath().resolve("netty_io_uring.tmp");
68          try {
69              // First, try calling a side-effect free JNI method to see if the library was already
70              // loaded by the application.
71              Native.createFile(tmpFile.toString());
72          } catch (UnsatisfiedLinkError ignore) {
73              // The library was not previously loaded, load it now.
74              loadNativeLibrary();
75          } finally {
76              tmpFile.toFile().delete();
77              try {
78                  if (selector != null) {
79                      selector.close();
80                  }
81              } catch (IOException ignore) {
82                  // Just ignore
83              }
84          }
85          Unix.registerInternal(Native::registerUnix);
86      }
87  
88      static final int SOCK_NONBLOCK = NativeStaticallyReferencedJniMethods.sockNonblock();
89      static final int SOCK_CLOEXEC = NativeStaticallyReferencedJniMethods.sockCloexec();
90      static final short AF_INET = (short) NativeStaticallyReferencedJniMethods.afInet();
91      static final short AF_INET6 = (short) NativeStaticallyReferencedJniMethods.afInet6();
92      static final short AF_UNIX = (short) NativeStaticallyReferencedJniMethods.afUnix();
93      static final int SIZEOF_SOCKADDR_STORAGE = NativeStaticallyReferencedJniMethods.sizeofSockaddrStorage();
94      static final int SIZEOF_SOCKADDR_UN = NativeStaticallyReferencedJniMethods.sizeofSockaddrUn();
95      static final int SOCKADDR_UN_OFFSETOF_SUN_FAMILY =
96              NativeStaticallyReferencedJniMethods.sockaddrUnOffsetofSunFamily();
97      static final int SOCKADDR_UN_OFFSETOF_SUN_PATH =
98              NativeStaticallyReferencedJniMethods.sockaddrUnOffsetofSunPath();
99      static final int MAX_SUN_PATH_LEN =
100             NativeStaticallyReferencedJniMethods.maxSunPathLen();
101     static final int SIZEOF_SOCKADDR_IN = NativeStaticallyReferencedJniMethods.sizeofSockaddrIn();
102     static final int SIZEOF_SOCKADDR_IN6 = NativeStaticallyReferencedJniMethods.sizeofSockaddrIn6();
103     static final int SOCKADDR_IN_OFFSETOF_SIN_FAMILY =
104             NativeStaticallyReferencedJniMethods.sockaddrInOffsetofSinFamily();
105     static final int SOCKADDR_IN_OFFSETOF_SIN_PORT = NativeStaticallyReferencedJniMethods.sockaddrInOffsetofSinPort();
106     static final int SOCKADDR_IN_OFFSETOF_SIN_ADDR = NativeStaticallyReferencedJniMethods.sockaddrInOffsetofSinAddr();
107     static final int IN_ADDRESS_OFFSETOF_S_ADDR = NativeStaticallyReferencedJniMethods.inAddressOffsetofSAddr();
108     static final int SOCKADDR_IN6_OFFSETOF_SIN6_FAMILY =
109             NativeStaticallyReferencedJniMethods.sockaddrIn6OffsetofSin6Family();
110     static final int SOCKADDR_IN6_OFFSETOF_SIN6_PORT =
111             NativeStaticallyReferencedJniMethods.sockaddrIn6OffsetofSin6Port();
112     static final int SOCKADDR_IN6_OFFSETOF_SIN6_FLOWINFO =
113             NativeStaticallyReferencedJniMethods.sockaddrIn6OffsetofSin6Flowinfo();
114     static final int SOCKADDR_IN6_OFFSETOF_SIN6_ADDR =
115             NativeStaticallyReferencedJniMethods.sockaddrIn6OffsetofSin6Addr();
116     static final int SOCKADDR_IN6_OFFSETOF_SIN6_SCOPE_ID =
117             NativeStaticallyReferencedJniMethods.sockaddrIn6OffsetofSin6ScopeId();
118     static final int IN6_ADDRESS_OFFSETOF_S6_ADDR = NativeStaticallyReferencedJniMethods.in6AddressOffsetofS6Addr();
119     static final int SIZEOF_SIZE_T = NativeStaticallyReferencedJniMethods.sizeofSizeT();
120     static final int SIZEOF_IOVEC = NativeStaticallyReferencedJniMethods.sizeofIovec();
121     static final int CMSG_SPACE = NativeStaticallyReferencedJniMethods.cmsgSpace();
122     static final int CMSG_SPACE_FOR_FD = NativeStaticallyReferencedJniMethods.cmsgSpaceForFd();
123     static final int CMSG_LEN = NativeStaticallyReferencedJniMethods.cmsgLen();
124     static final int CMSG_LEN_FOR_FD = NativeStaticallyReferencedJniMethods.cmsgLenForFd();
125     static final int MSG_CONTROL_LEN_FOR_FD = NativeStaticallyReferencedJniMethods.msgControlLenForFd();
126     static final int CMSG_OFFSETOF_CMSG_LEN = NativeStaticallyReferencedJniMethods.cmsghdrOffsetofCmsgLen();
127     static final int CMSG_OFFSETOF_CMSG_LEVEL = NativeStaticallyReferencedJniMethods.cmsghdrOffsetofCmsgLevel();
128     static final int CMSG_OFFSETOF_CMSG_TYPE = NativeStaticallyReferencedJniMethods.cmsghdrOffsetofCmsgType();
129 
130     static final int IO_URING_BUFFER_RING_TAIL = NativeStaticallyReferencedJniMethods.ioUringBufferRingOffsetTail();
131 
132     static final int IOVEC_OFFSETOF_IOV_BASE = NativeStaticallyReferencedJniMethods.iovecOffsetofIovBase();
133     static final int IOVEC_OFFSETOF_IOV_LEN = NativeStaticallyReferencedJniMethods.iovecOffsetofIovLen();
134     static final int SIZEOF_MSGHDR = NativeStaticallyReferencedJniMethods.sizeofMsghdr();
135     static final int MSGHDR_OFFSETOF_MSG_NAME = NativeStaticallyReferencedJniMethods.msghdrOffsetofMsgName();
136     static final int MSGHDR_OFFSETOF_MSG_NAMELEN = NativeStaticallyReferencedJniMethods.msghdrOffsetofMsgNamelen();
137     static final int MSGHDR_OFFSETOF_MSG_IOV = NativeStaticallyReferencedJniMethods.msghdrOffsetofMsgIov();
138     static final int MSGHDR_OFFSETOF_MSG_IOVLEN = NativeStaticallyReferencedJniMethods.msghdrOffsetofMsgIovlen();
139     static final int MSGHDR_OFFSETOF_MSG_CONTROL = NativeStaticallyReferencedJniMethods.msghdrOffsetofMsgControl();
140     static final int MSGHDR_OFFSETOF_MSG_CONTROLLEN =
141             NativeStaticallyReferencedJniMethods.msghdrOffsetofMsgControllen();
142     static final int MSGHDR_OFFSETOF_MSG_FLAGS = NativeStaticallyReferencedJniMethods.msghdrOffsetofMsgFlags();
143     static final int POLLIN = NativeStaticallyReferencedJniMethods.pollin();
144     static final int POLLOUT = NativeStaticallyReferencedJniMethods.pollout();
145     static final int POLLRDHUP = NativeStaticallyReferencedJniMethods.pollrdhup();
146     static final int ERRNO_ECANCELED_NEGATIVE = -NativeStaticallyReferencedJniMethods.ecanceled();
147     static final int ERRNO_ETIME_NEGATIVE = -NativeStaticallyReferencedJniMethods.etime();
148     static final int ERRNO_NOBUFS_NEGATIVE = -NativeStaticallyReferencedJniMethods.enobufs();
149 
150     static final int PAGE_SIZE = NativeStaticallyReferencedJniMethods.pageSize();
151 
152     static final int SIZEOF_IOURING_BUF = NativeStaticallyReferencedJniMethods.sizeofIoUringBuf();
153     static final int IOURING_BUFFER_OFFSETOF_ADDR = NativeStaticallyReferencedJniMethods.ioUringBufferOffsetAddr();
154     static final int IOURING_BUFFER_OFFSETOF_LEN = NativeStaticallyReferencedJniMethods.ioUringBufferOffsetLen();
155     static final int IOURING_BUFFER_OFFSETOF_BID = NativeStaticallyReferencedJniMethods.ioUringBufferOffsetBid();
156 
157     // These constants must be defined to have the same numeric value as their corresponding
158     // ordinal in the enum defined in the io_uring.h header file.
159     // DO NOT CHANGE THESE VALUES!
160     static final byte IORING_OP_NOP = 0; // Specified by IORING_OP_NOP in io_uring.h
161     static final byte IORING_OP_READV = 1; // Specified by IORING_OP_READV in io_uring.h
162     static final byte IORING_OP_WRITEV = 2; // Specified by IORING_OP_WRITEV in io_uring.h
163     static final byte IORING_OP_FSYNC = 3; // Specified by IORING_OP_FSYNC in io_uring.h
164     static final byte IORING_OP_READ_FIXED = 4; // Specified by IORING_OP_READ_FIXED in io_uring.h
165     static final byte IORING_OP_WRITE_FIXED = 5; // Specified by IORING_OP_WRITE_FIXED in io_uring.h
166     static final byte IORING_OP_POLL_ADD = 6; // Specified by IORING_OP_POLL_ADD in io_uring.h
167     static final byte IORING_OP_POLL_REMOVE = 7; // Specified by IORING_OP_POLL_REMOVE in io_uring.h
168     static final byte IORING_OP_SYNC_FILE_RANGE = 8; // Specified by IORING_OP_SYNC_FILE_RANGE in io_uring.h
169     static final byte IORING_OP_SENDMSG = 9; // Specified by IORING_OP_SENDMSG in io_uring.h
170     static final byte IORING_OP_RECVMSG = 10; // Specified by IORING_OP_RECVMSG in io_uring.h
171     static final byte IORING_OP_TIMEOUT = 11; // Specified by IORING_OP_TIMEOUT in io_uring.h
172     static final byte IORING_OP_TIMEOUT_REMOVE = 12; // Specified by IORING_OP_TIMEOUT_REMOVE in io_uring.h
173     static final byte IORING_OP_ACCEPT = 13; // Specified by IORING_OP_ACCEPT in io_uring.h
174     static final byte IORING_OP_ASYNC_CANCEL = 14; // Specified by IORING_OP_ASYNC_CANCEL in io_uring.h
175     static final byte IORING_OP_LINK_TIMEOUT = 15; // Specified by IORING_OP_LINK_TIMEOUT in io_uring.h
176     static final byte IORING_OP_CONNECT = 16; // Specified by IORING_OP_CONNECT in io_uring.h
177     static final byte IORING_OP_FALLOCATE = 17; // Specified by IORING_OP_FALLOCATE in io_uring.h
178     static final byte IORING_OP_OPENAT = 18; // Specified by IORING_OP_OPENAT in io_uring.h
179     static final byte IORING_OP_CLOSE = 19; // Specified by IORING_OP_CLOSE in io_uring.h
180     static final byte IORING_OP_FILES_UPDATE = 20; // Specified by IORING_OP_FILES_UPDATE in io_uring.h
181     static final byte IORING_OP_STATX = 21; // Specified by IORING_OP_STATX in io_uring.h
182     static final byte IORING_OP_READ = 22; // Specified by IORING_OP_READ in io_uring.h
183     static final byte IORING_OP_WRITE = 23; // Specified by IORING_OP_WRITE in io_uring.h
184     static final byte IORING_OP_FADVISE = 24; // Specified by IORING_OP_FADVISE in io_uring.h
185     static final byte IORING_OP_MADVISE = 25; // Specified by IORING_OP_MADVISE in io_uring.h
186     static final byte IORING_OP_SEND = 26; // Specified by IORING_OP_SEND in io_uring.h
187     static final byte IORING_OP_RECV = 27; // Specified by IORING_OP_RECV in io_uring.h
188     static final byte IORING_OP_OPENAT2 = 28; // Specified by IORING_OP_OPENAT2 in io_uring.h
189     static final byte IORING_OP_EPOLL_CTL = 29; // Specified by IORING_OP_EPOLL_CTL in io_uring.h
190     static final byte IORING_OP_SPLICE = 30; // Specified by IORING_OP_SPLICE in io_uring.h
191     static final byte IORING_OP_PROVIDE_BUFFERS = 31; // Specified by IORING_OP_PROVIDE_BUFFERS in io_uring.h
192     static final byte IORING_OP_REMOVE_BUFFERS = 32; // Specified by IORING_OP_REMOVE_BUFFERS in io_uring.h
193     static final byte IORING_OP_TEE = 33; // Specified by IORING_OP_TEE in io_uring.h
194     static final byte IORING_OP_SHUTDOWN = 34; // Specified by IORING_OP_SHUTDOWN in io_uring.h
195     static final byte IORING_OP_RENAMEAT = 35; // Specified by IORING_OP_RENAMEAT in io_uring.h
196     static final byte IORING_OP_UNLINKAT = 36; // Specified by IORING_OP_UNLINKAT in io_uring.h
197     static final byte IORING_OP_MKDIRAT = 37; // Specified by IORING_OP_MKDIRAT in io_uring.h
198     static final byte IORING_OP_SYMLINKAT = 38; // Specified by IORING_OP_SYMLINKAT in io_uring.h
199     static final byte IORING_OP_LINKAT = 39; // Specified by IORING_OP_LINKAT in io_uring.h
200     static final byte IORING_OP_MSG_RING = 40;
201     static final byte IORING_OP_FSETXATTR = 41;
202     static final byte IORING_OP_SETXATTR = 42;
203     static final byte IORING_OP_FGETXATTR = 43;
204     static final byte IORING_OP_GETXATTR = 44;
205     static final byte IORING_OP_SOCKET = 45;
206     static final byte IORING_OP_URING_CMD = 46;
207     static final byte IORING_OP_SEND_ZC = 47;
208     static final byte IORING_OP_SENDMSG_ZC = 48;
209     static final byte IORING_OP_READ_MULTISHOT = 49;
210     static final byte IORING_OP_WAITID = 50;
211     static final byte IORING_OP_FUTEX_WAIT = 51;
212     static final byte IORING_OP_FUTEX_WAKE = 52;
213     static final byte IORING_OP_FUTEX_WAITV = 53;
214     static final byte IORING_OP_FIXED_FD_INSTALL = 54;
215     static final byte IORING_OP_FTRUNCATE = 55;
216     static final byte IORING_OP_BIND = 56;
217     static final byte IORING_CQE_F_BUFFER = 1 << 0;
218     static final byte IORING_CQE_F_MORE = 1 << 1;
219     static final byte IORING_CQE_F_SOCK_NONEMPTY = 1 << 2;
220     static final byte IORING_CQE_F_BUF_MORE = 1 << 4;
221 
222     static final int IORING_SETUP_CQSIZE = 1 << 3;
223     static final int IORING_SETUP_CLAMP = 1 << 4;
224 
225     static final int IORING_SETUP_R_DISABLED = 1 << 6;
226     static final int IORING_SETUP_SUBMIT_ALL = 1 << 7;
227     static final int IORING_SETUP_SINGLE_ISSUER = 1 << 12;
228     static final int IORING_SETUP_DEFER_TASKRUN = 1 << 13;
229     static final int IORING_CQE_BUFFER_SHIFT = 16;
230 
231     static final short IORING_POLL_ADD_MULTI = 1 << 0;
232 
233     static final short IORING_RECVSEND_POLL_FIRST = 1 << 0;
234     static final short IORING_RECVSEND_BUNDLE = 1 << 4;
235     static final short IORING_RECV_MULTISHOT = 1 << 1;
236 
237     static final short IORING_ACCEPT_MULTISHOT = 1 << 0;
238     static final short IORING_ACCEPT_DONTWAIT = 1 << 1;
239     static final short IORING_ACCEPT_POLL_FIRST = 1 << 2;
240 
241     static final int IORING_FEAT_SUBMIT_STABLE = 1 << 2;
242     static final int IORING_FEAT_RECVSEND_BUNDLE = 1 << 14;
243 
244     static final int SPLICE_F_MOVE = 1;
245 
246     static final int IOU_PBUF_RING_INC = 2;
247     static String opToStr(byte op) {
248         switch (op) {
249             case IORING_OP_NOP: return "NOP";
250             case IORING_OP_READV: return "READV";
251             case IORING_OP_WRITEV: return "WRITEV";
252             case IORING_OP_FSYNC: return "FSYNC";
253             case IORING_OP_READ_FIXED: return "READ_FIXED";
254             case IORING_OP_WRITE_FIXED: return "WRITE_FIXED";
255             case IORING_OP_POLL_ADD: return "POLL_ADD";
256             case IORING_OP_POLL_REMOVE: return "POLL_REMOVE";
257             case IORING_OP_SYNC_FILE_RANGE: return "SYNC_FILE_RANGE";
258             case IORING_OP_SENDMSG: return "SENDMSG";
259             case IORING_OP_RECVMSG: return "RECVMSG";
260             case IORING_OP_TIMEOUT: return "TIMEOUT";
261             case IORING_OP_TIMEOUT_REMOVE: return "TIMEOUT_REMOVE";
262             case IORING_OP_ACCEPT: return "ACCEPT";
263             case IORING_OP_ASYNC_CANCEL: return "ASYNC_CANCEL";
264             case IORING_OP_LINK_TIMEOUT: return "LINK_TIMEOUT";
265             case IORING_OP_CONNECT: return "CONNECT";
266             case IORING_OP_FALLOCATE: return "FALLOCATE";
267             case IORING_OP_OPENAT: return "OPENAT";
268             case IORING_OP_CLOSE: return "CLOSE";
269             case IORING_OP_FILES_UPDATE: return "FILES_UPDATE";
270             case IORING_OP_STATX: return "STATX";
271             case IORING_OP_READ: return "READ";
272             case IORING_OP_WRITE: return "WRITE";
273             case IORING_OP_FADVISE: return "FADVISE";
274             case IORING_OP_MADVISE: return "MADVISE";
275             case IORING_OP_SEND: return "SEND";
276             case IORING_OP_RECV: return "RECV";
277             case IORING_OP_OPENAT2: return "OPENAT2";
278             case IORING_OP_EPOLL_CTL: return "EPOLL_CTL";
279             case IORING_OP_SPLICE: return "SPLICE";
280             case IORING_OP_PROVIDE_BUFFERS: return "PROVIDE_BUFFERS";
281             case IORING_OP_REMOVE_BUFFERS: return "REMOVE_BUFFERS";
282             case IORING_OP_TEE: return "TEE";
283             case IORING_OP_SHUTDOWN: return "SHUTDOWN";
284             case IORING_OP_RENAMEAT: return "RENAMEAT";
285             case IORING_OP_UNLINKAT: return "UNLINKAT";
286             case IORING_OP_MKDIRAT: return "MKDIRAT";
287             case IORING_OP_SYMLINKAT: return "SYMLINKAT";
288             case IORING_OP_LINKAT: return "LINKAT";
289             default: return "[OP CODE " + op + ']';
290         }
291     }
292 
293     static final int IORING_ENTER_GETEVENTS = NativeStaticallyReferencedJniMethods.ioringEnterGetevents();
294     static final int IORING_ENTER_REGISTERED_RING = 1 << 4;
295     static final int IOSQE_ASYNC = NativeStaticallyReferencedJniMethods.iosqeAsync();
296     static final int IOSQE_LINK = NativeStaticallyReferencedJniMethods.iosqeLink();
297     static final int IOSQE_IO_DRAIN = NativeStaticallyReferencedJniMethods.iosqeDrain();
298     static final int IOSQE_BUFFER_SELECT = NativeStaticallyReferencedJniMethods.iosqeBufferSelect();
299     static final int IOSQE_CQE_SKIP_SUCCESS = 1 << 6;
300     static final int MSG_DONTWAIT = NativeStaticallyReferencedJniMethods.msgDontwait();
301     static final int MSG_FASTOPEN = NativeStaticallyReferencedJniMethods.msgFastopen();
302     static final int SOL_UDP = NativeStaticallyReferencedJniMethods.solUdp();
303     static final int SOL_SOCKET = NativeStaticallyReferencedJniMethods.solSocket();
304     static final int UDP_SEGMENT = NativeStaticallyReferencedJniMethods.udpSegment();
305     static final int SCM_RIGHTS = NativeStaticallyReferencedJniMethods.scmRights();
306     private static final int TFO_ENABLED_CLIENT_MASK = 0x1;
307     private static final int TFO_ENABLED_SERVER_MASK = 0x2;
308     private static final int TCP_FASTOPEN_MODE = NativeStaticallyReferencedJniMethods.tcpFastopenMode();
309     /**
310      * <a href ="https://www.kernel.org/doc/Documentation/networking/ip-sysctl.txt">tcp_fastopen</a> client mode enabled
311      * state.
312      */
313     static final boolean IS_SUPPORTING_TCP_FASTOPEN_CLIENT =
314             (TCP_FASTOPEN_MODE & TFO_ENABLED_CLIENT_MASK) == TFO_ENABLED_CLIENT_MASK;
315     /**
316      * <a href ="https://www.kernel.org/doc/Documentation/networking/ip-sysctl.txt">tcp_fastopen</a> server mode enabled
317      * state.
318      */
319     static final boolean IS_SUPPORTING_TCP_FASTOPEN_SERVER =
320             (TCP_FASTOPEN_MODE & TFO_ENABLED_SERVER_MASK) == TFO_ENABLED_SERVER_MASK;
321 
322     private static final int[] REQUIRED_IORING_OPS = {
323             IORING_OP_POLL_ADD,
324             IORING_OP_TIMEOUT,
325             IORING_OP_ACCEPT,
326             IORING_OP_READ,
327             IORING_OP_WRITE,
328             IORING_OP_POLL_REMOVE,
329             IORING_OP_CONNECT,
330             IORING_OP_CLOSE,
331             IORING_OP_WRITEV,
332             IORING_OP_SENDMSG,
333             IORING_OP_RECVMSG,
334             IORING_OP_ASYNC_CANCEL,
335             IORING_OP_RECV,
336             IORING_OP_NOP,
337             IORING_OP_SHUTDOWN,
338             IORING_OP_SEND
339     };
340 
341     static int setupFlags() {
342         int flags = Native.IORING_SETUP_R_DISABLED | Native.IORING_SETUP_CLAMP;
343         if (IoUring.isSetupSubmitAllSupported()) {
344             flags |= Native.IORING_SETUP_SUBMIT_ALL;
345         }
346 
347         // See https://github.com/axboe/liburing/wiki/io_uring-and-networking-in-2023#task-work
348         if (IoUring.isSetupSingleIssuerSupported()) {
349             flags |= Native.IORING_SETUP_SINGLE_ISSUER;
350         }
351         if (IoUring.isSetupDeferTaskrunSupported()) {
352             flags |= Native.IORING_SETUP_DEFER_TASKRUN;
353         }
354         return flags;
355     }
356 
357     static RingBuffer createRingBuffer(int ringSize, int setupFlags) {
358         return createRingBuffer(ringSize, ringSize * 2, setupFlags);
359     }
360 
361     static RingBuffer createRingBuffer(int ringSize, int cqeSize, int setupFlags) {
362         ObjectUtil.checkPositive(ringSize, "ringSize");
363         ObjectUtil.checkPositive(cqeSize, "cqeSize");
364         long[] values = ioUringSetup(ringSize, cqeSize, setupFlags);
365         assert values.length == 18;
366         long cqkhead = values[0];
367         long cqktail = values[1];
368         int cqringMask = (int) values[2];
369         int cqringEntries = (int) values[3];
370         long cqArrayAddress = values[4];
371         int cqringSize = (int) values[5];
372         long cqringAddress = values[6];
373         int cqringFd = (int) values[7];
374         int cqringCapacity = (int) values[8];
375         CompletionQueue completionQueue = new CompletionQueue(
376                 Buffer.wrapMemoryAddressWithNativeOrder(cqkhead, Integer.BYTES),
377                 Buffer.wrapMemoryAddressWithNativeOrder(cqktail, Integer.BYTES),
378                 cqringMask,
379                 cqringEntries,
380                 Buffer.wrapMemoryAddressWithNativeOrder(cqArrayAddress, cqringEntries * CompletionQueue.CQE_SIZE),
381                 cqringSize,
382                 cqringAddress,
383                 cqringFd,
384                 cqringCapacity);
385 
386         long sqkhead = values[9];
387         long sqktail = values[10];
388         int sqringMask = (int) values[11];
389         int sqringEntries = (int) values[12];
390         long sqArrayAddress = values[13];
391         int sqringSize = (int) values[14];
392         long sqringAddress = values[15];
393         int sqringFd = (int) values[16];
394         SubmissionQueue submissionQueue = new SubmissionQueue(
395                 Buffer.wrapMemoryAddressWithNativeOrder(sqkhead, Integer.BYTES),
396                 Buffer.wrapMemoryAddressWithNativeOrder(sqktail, Integer.BYTES),
397                 sqringMask,
398                 sqringEntries,
399                 Buffer.wrapMemoryAddressWithNativeOrder(sqArrayAddress, sqringEntries * SubmissionQueue.SQE_SIZE),
400                 sqringSize,
401                 sqringAddress,
402                 sqringFd);
403         return new RingBuffer(submissionQueue, completionQueue, (int) values[17]);
404     }
405 
406     static void checkAllIOSupported(int ringFd) {
407         if (!ioUringProbe(ringFd, REQUIRED_IORING_OPS)) {
408             throw new UnsupportedOperationException("Not all operations are supported: "
409                     + Arrays.toString(REQUIRED_IORING_OPS));
410         }
411     }
412 
413     static boolean isRecvMultishotSupported() {
414         // Added in the same release as IORING_SETUP_SINGLE_ISSUER.
415         return Native.ioUringSetupSupportsFlags(Native.IORING_SETUP_SINGLE_ISSUER);
416     }
417 
418     static boolean isAcceptMultishotSupported(int ringFd) {
419         // IORING_OP_SOCKET was added in the same release (5.19);
420         return ioUringProbe(ringFd, new int[] { Native.IORING_OP_SOCKET });
421     }
422 
423     static boolean isCqeFSockNonEmptySupported(int ringFd) {
424         // IORING_OP_SOCKET was added in the same release (5.19);
425         return ioUringProbe(ringFd, new int[] { Native.IORING_OP_SOCKET });
426     }
427 
428     static boolean isSpliceSupported(int ringFd) {
429         // IORING_OP_SPLICE Available since 5.7
430         return ioUringProbe(ringFd, new int[] { Native.IORING_OP_SPLICE });
431     }
432 
433     static boolean isPollAddMultiShotSupported(int ringfd) {
434         // Was added in the same release and we also need this feature to correctly handle edge-triggered mode.
435         return isCqeFSockNonEmptySupported(ringfd);
436     }
437 
438     /**
439      * check current kernel version whether support io_uring_register_io_wq_worker
440      * Available since 5.15.
441      * @return true if support io_uring_register_io_wq_worker
442      */
443     static boolean isRegisterIoWqWorkerSupported(int ringFd) {
444         // See https://github.com/torvalds/linux/blob/v5.5/fs/io_uring.c#L5488C10-L5488C16
445         int result = ioUringRegisterIoWqMaxWorkers(ringFd, 0, 0);
446         if (result >= 0) {
447             return true;
448         }
449         // This is not supported and so will return -EINVAL
450         return false;
451     }
452 
453     static boolean isRegisterBufferRingSupported(int ringFd, int flags) {
454         int entries = 2;
455         short bgid = 1;
456         long result = ioUringRegisterBufRing(ringFd, entries, bgid, flags);
457         if (result >= 0) {
458             ioUringUnRegisterBufRing(ringFd, result, entries, bgid);
459             return true;
460         }
461         // This is not supported and so will return -EINVAL
462         return false;
463     }
464 
465     static void checkKernelVersion(String kernelVersion) {
466         boolean enforceKernelVersion = SystemPropertyUtil.getBoolean(
467                 "io.netty.transport.iouring.enforceKernelVersion", true);
468         boolean kernelSupported = checkKernelVersion(kernelVersion, 5, 9);
469         if (!kernelSupported) {
470             if (enforceKernelVersion) {
471                 throw new UnsupportedOperationException(
472                         "you need at least kernel version 5.9, current kernel version: " + kernelVersion);
473             } else {
474                 logger.debug("Detected kernel " + kernelVersion + " does not match minimum version of 5.9, " +
475                         "trying to use io_uring anyway");
476             }
477         }
478     }
479 
480     private static boolean checkKernelVersion(String kernelVersion, int major, int minor) {
481         String[] versionComponents = kernelVersion.split("\\.");
482         if (versionComponents.length < 3) {
483             return false;
484         }
485         int nativeMajor;
486         try {
487             nativeMajor = Integer.parseInt(versionComponents[0]);
488         } catch (NumberFormatException e) {
489             return false;
490         }
491 
492         if (nativeMajor < major) {
493             return false;
494         }
495 
496         if (nativeMajor > major) {
497             return true;
498         }
499 
500         int nativeMinor;
501         try {
502             nativeMinor = Integer.parseInt(versionComponents[1]);
503         } catch (NumberFormatException e) {
504             return false;
505         }
506 
507         return nativeMinor >= minor;
508     }
509 
510     static native boolean ioUringSetupSupportsFlags(int setupFlags);
511     private static native boolean ioUringProbe(int ringFd, int[] ios);
512     private static native long[] ioUringSetup(int entries, int cqeSize, int setupFlags);
513 
514     static native int ioUringRegisterIoWqMaxWorkers(int ringFd, int maxBoundedValue, int maxUnboundedValue);
515     static native int ioUringRegisterEnableRings(int ringFd);
516     static native int ioUringRegisterRingFds(int ringFds);
517 
518     static native long ioUringRegisterBufRing(int ringFd, int entries, short bufferGroup, int flags);
519     static native int ioUringUnRegisterBufRing(int ringFd, long ioUringBufRingAddr, int entries, short bufferGroupId);
520     static native int ioUringBufRingSize(int entries);
521     static native int ioUringEnter(int ringFd, int toSubmit, int minComplete, int flags);
522 
523     static native void eventFdWrite(int fd, long value);
524 
525     static int getFd(DefaultFileRegion fileChannel) {
526         return getFd0(fileChannel);
527     }
528 
529     private static native int getFd0(Object fileChannel);
530 
531     static FileDescriptor newBlockingEventFd() {
532         return new FileDescriptor(blockingEventFd());
533     }
534 
535     static native void ioUringExit(long submissionQueueArrayAddress, int submissionQueueRingEntries,
536                                           long submissionQueueRingAddress, int submissionQueueRingSize,
537                                           long completionQueueRingAddress, int completionQueueRingSize,
538                                           int ringFd, int enterRingFd);
539 
540     private static native int blockingEventFd();
541 
542     // for testing only!
543     static native int createFile(String name);
544 
545     private static native int registerUnix();
546 
547     static native long cmsghdrData(long hdrAddr);
548 
549     static native String kernelVersion();
550 
551     private Native() {
552         // utility
553     }
554 
555     // From io_uring native library
556     private static void loadNativeLibrary() {
557         String name = PlatformDependent.normalizedOs().toLowerCase(Locale.ROOT).trim();
558         if (!name.startsWith("linux")) {
559             throw new IllegalStateException("Only supported on Linux");
560         }
561         String staticLibName = "netty_transport_native_io_uring42";
562         String sharedLibName = staticLibName + '_' + PlatformDependent.normalizedArch();
563         ClassLoader cl = PlatformDependent.getClassLoader(Native.class);
564         try {
565             NativeLibraryLoader.load(sharedLibName, cl);
566         } catch (UnsatisfiedLinkError e1) {
567             try {
568                 NativeLibraryLoader.load(staticLibName, cl);
569                 logger.info("Failed to load io_uring");
570             } catch (UnsatisfiedLinkError e2) {
571                 ThrowableUtil.addSuppressed(e1, e2);
572                 throw e1;
573             }
574         }
575     }
576 }