bsd/sys/kpi_socket.h

   1 /*
   2  * Copyright (c) 2008-2012 Apple Inc. All rights reserved.
   3  *
   4  * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
   5  *
   6  * This file contains Original Code and/or Modifications of Original Code
   7  * as defined in and that are subject to the Apple Public Source License
   8  * Version 2.0 (the 'License'). You may not use this file except in
   9  * compliance with the License. The rights granted to you under the License
  10  * may not be used to create, or enable the creation or redistribution of,
  11  * unlawful or unlicensed copies of an Apple operating system, or to
  12  * circumvent, violate, or enable the circumvention or violation of, any
  13  * terms of an Apple operating system software license agreement.
  14  *
  15  * Please obtain a copy of the License at
  16  * http://www.opensource.apple.com/apsl/ and read it before using this file.
  17  *
  18  * The Original Code and all software distributed under the License are
  19  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  20  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  21  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
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  23  * Please see the License for the specific language governing rights and
  24  * limitations under the License.
  25  *
  26  * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
  27  */
  28 /*!
  29         @header kpi_socket.h
  30         This header defines an API for creating and interacting with sockets
  31         in the kernel. It is possible to create sockets in the kernel
  32         without an associated file descriptor. In some cases, a reference to
  33         the socket may be known while the file descriptor is not. These
  34         functions can be used for interacting with sockets in the kernel.
  35         The API is similar to the user space socket API.
  36  */
  37 #ifndef __KPI_SOCKET__
  38 #define __KPI_SOCKET__
  39
  40 #include <sys/types.h>
  41 #include <sys/kernel_types.h>
  42 #include <sys/socket.h>
  43
  44 __BEGIN_DECLS
  45
  46 struct timeval;
  47
  48 /*!
  49         @typedef sock_upcall
  50
  51         @discussion sock_upcall is used by a socket to notify an in kernel
  52                 client that data is waiting. Instead of making blocking calls in
  53                 the kernel, a client can specify an upcall which will be called
  54                 when data is available or the socket is ready for sending.
  55
  56                 Calls to your upcall function are not serialized and may be
  57                 called concurrently from multiple threads in the kernel.
  58
  59                 Your upcall function will be called:
  60                     when there is data more than the low water mark for reading,
  61                     or when there is space for a write,
  62                     or when there is a connection to accept,
  63                     or when a socket is connected,
  64                     or when a socket is closed or disconnected
  65
  66         @param so A reference to the socket that's ready.
  67         @param cookie The cookie passed in when the socket was created.
  68         @param waitf Indicates whether or not it's safe to block.
  69 */
  70 typedef void (*sock_upcall)(socket_t so, void *cookie, int waitf);
  71
  72 #ifdef KERNEL_PRIVATE
  73 /*!
  74         @typedef sock_evupcall
  75
  76         @discussion sock_evupcall is used by a socket to notify an in kernel
  77                 client when an event occurs. Instead of making blocking calls in
  78                 the kernel, a client can specify an upcall which will be called
  79                 when an event status is available.
  80         @param so A reference to the socket that's ready.
  81         @param cookie The cookie passed in when the socket was created.
  82         @param int Indicates the event as defined by SO_FILT_HINT_*
  83 */
  84 typedef void (*sock_evupcall)(socket_t so, void *cookie, u_int32_t event);
  85 #endif /* KERNEL_PRIVATE */
  86
  87 /*!
  88         @function sock_accept
  89         @discussion Accepts an incoming connection on a socket. See 'man 2
  90                 accept' for more information. Allocating a socket in this manner
  91                 creates a socket with no associated file descriptor.
  92         @param so The listening socket you'd like to accept a connection on.
  93         @param from A pointer to a socket address that will be filled in
  94                 with the address the connection is from.
  95         @param fromlen Maximum length of from.
  96         @param flags Supports MSG_DONTWAIT and MSG_USEUPCALL. If
  97                 MSG_DONTWAIT is set, accept will return EWOULDBLOCK if there are
  98                 no connections ready to be accepted. If MSG_USEUPCALL is set,
  99                 the created socket will use the same upcall function attached to
 100                 the original socket.
 101         @param callback A notifier function to be called when an event
 102                 occurs on the socket. This may be NULL.
 103         @param cookie A cookie passed directly to the callback.
 104         @param new_so Upon success, *new_so will be a reference to a new
 105                 socket for tracking the connection.
 106         @result 0 on success otherwise the errno error.
 107  */
 108 extern errno_t sock_accept(socket_t so, struct sockaddr *from, int fromlen,
 109     int flags, sock_upcall callback, void *cookie, socket_t *new_so);
 110
 111 /*!
 112         @function sock_bind
 113         @discussion Binds a socket to a specific address. See 'man 2 bind'
 114                 for more information.
 115         @param so The socket to be bound.
 116         @param to The local address the socket should be bound to.
 117         @result 0 on success otherwise the errno error.
 118  */
 119 extern errno_t sock_bind(socket_t so, const struct sockaddr *to);
 120
 121 /*!
 122         @function sock_connect
 123         @discussion Initiates a connection on the socket. See 'man 2
 124                 connect' for more information.
 125         @param so The socket to be connect.
 126         @param to The remote address the socket should connect to.
 127         @param flags Flags for connecting. The only flag supported so far is
 128                 MSG_DONTWAIT. MSG_DONTWAIT will perform a non-blocking connect.
 129                 sock_connect will return immediately with EINPROGRESS. The
 130                 upcall, if supplied, will be called when the connection is
 131                 completed.
 132         @result 0 on success, EINPROGRESS for a non-blocking connect that
 133                 has not completed, otherwise the errno error.
 134  */
 135 extern errno_t sock_connect(socket_t so, const struct sockaddr *to, int flags);
 136
 137 #ifdef KERNEL_PRIVATE
 138 /*
 139         This function was added to support NFS. NFS does something funny,
 140         setting a short timeout and checking to see if it should abort the
 141         connect every two seconds. Ideally, NFS would use the upcall to be
 142         notified when the connect is complete.
 143
 144         If you feel you need to use this function, please contact us to
 145         explain why.
 146
 147         @function sock_connectwait
 148         @discussion Allows a caller to wait on a socket connect.
 149         @param so The socket being connected.
 150         @param tv The amount of time to wait.
 151         @result 0 on success otherwise the errno error. EINPROGRESS will be
 152                 returned if the connection did not complete in the timeout
 153                 specified.
 154  */
 155 extern errno_t sock_connectwait(socket_t so, const struct timeval *tv);
 156 #endif /* KERNEL_PRIVATE */
 157
 158 /*!
 159         @function sock_getpeername
 160         @discussion Retrieves the remote address of a connected socket. See
 161                 'man 2 getpeername'.
 162         @param so The socket.
 163         @param peername Storage for the peer name.
 164         @param peernamelen Length of storage for the peer name.
 165         @result 0 on success otherwise the errno error.
 166  */
 167 extern errno_t sock_getpeername(socket_t so, struct sockaddr *peername,
 168     int peernamelen);
 169
 170 /*!
 171         @function sock_getsockname
 172         @discussion Retrieves the local address of a socket. See 'man 2
 173                 getsockname'.
 174         @param so The socket.
 175         @param sockname Storage for the local name.
 176         @param socknamelen Length of storage for the socket name.
 177         @result 0 on success otherwise the errno error.
 178  */
 179 extern errno_t sock_getsockname(socket_t so, struct sockaddr *sockname,
 180     int socknamelen);
 181
 182 /*!
 183         @function sock_getsockopt
 184         @discussion Retrieves a socket option. See 'man 2 getsockopt'.
 185         @param so The socket.
 186         @param level Level of the socket option.
 187         @param optname The option name.
 188         @param optval The option value.
 189         @param optlen The length of optval, returns the actual length.
 190         @result 0 on success otherwise the errno error.
 191  */
 192 extern errno_t sock_getsockopt(socket_t so, int level, int optname,
 193     void *optval, int *optlen);
 194
 195 /*!
 196         @function sock_ioctl
 197         @discussion Performs an ioctl operation on a socket. See 'man 2 ioctl'.
 198         @param so The socket.
 199         @param request The ioctl name.
 200         @param argp The argument.
 201         @result 0 on success otherwise the errno error.
 202  */
 203 extern errno_t sock_ioctl(socket_t so, unsigned long request, void *argp);
 204
 205 /*!
 206         @function sock_setsockopt
 207         @discussion Sets a socket option. See 'man 2 setsockopt'.
 208         @param so The socket.
 209         @param level Level of the socket option.
 210         @param optname The option name.
 211         @param optval The option value.
 212         @param optlen The length of optval.
 213         @result 0 on success otherwise the errno error.
 214  */
 215 extern errno_t sock_setsockopt(socket_t so, int level, int optname,
 216     const void *optval, int optlen);
 217
 218 #ifdef KERNEL_PRIVATE
 219 /*
 220         This function was added to support AFP setting the traffic class
 221         for a backup stream within a wireless LAN or over link-local address.
 222
 223         If you feel you need to use this function, please contact us to
 224         explain why.
 225
 226         @function sock_settclassopt
 227         @discussion Allows a caller to set the traffic class.
 228         @param so The socket.
 229         @param optval The option value.
 230         @param optlen The length of optval.
 231         @result 0 on success otherwise the errno error.
 232  */
 233 extern errno_t sock_settclassopt(socket_t so, const void* optval, size_t optlen);
 234
 235 /*
 236         This function was added to support AFP getting the traffic class
 237         set on a stream.
 238
 239         This is also a private API, please contact us if you need to use it.
 240
 241         @function sockgettclassopt
 242         @discussion Allows a caller to get the traffic class.
 243         @param so The socket.
 244         @param optval The option value.
 245         @param optlen The length of optval, returns the actual length.
 246         @result 0 on success otherwise the errno error.
 247 */
 248 extern errno_t sock_gettclassopt(socket_t so, void* optval, size_t* optlen);
 249
 250 #ifdef XNU_KERNEL_PRIVATE
 251 extern void socket_set_traffic_mgt_flags_locked(socket_t so, u_int32_t flags);
 252 extern void socket_clear_traffic_mgt_flags_locked(socket_t so, u_int32_t flags);
 253 #endif /* XNU_KERNEL_PRIVATE */
 254 #ifdef BSD_KERNEL_PRIVATE
 255 extern void socket_set_traffic_mgt_flags(socket_t so, u_int32_t flags);
 256 extern void socket_clear_traffic_mgt_flags(socket_t so, u_int32_t flags);
 257 extern errno_t socket_defunct(struct proc *, socket_t so, int);
 258 extern errno_t sock_receive_internal(socket_t, struct msghdr *, mbuf_t *,
 259     int, size_t *);
 260 #endif /* BSD_KERNEL_PRIVATE */
 261 #endif /* KERNEL_PRIVATE */
 262
 263 /*!
 264         @function sock_listen
 265         @discussion Indicate that the socket should start accepting incoming
 266                 connections. See 'man 2 listen'.
 267         @param so The socket.
 268         @param backlog The maximum length of the queue of pending connections.
 269         @result 0 on success otherwise the errno error.
 270  */
 271 extern errno_t sock_listen(socket_t so, int backlog);
 272
 273 /*!
 274         @function sock_receive
 275         @discussion Receive data from a socket. Similar to recvmsg. See 'man
 276                 2 recvmsg' for more information about receiving data.
 277         @param so The socket.
 278         @param msg The msg describing how the data should be received.
 279         @param flags See 'man 2 recvmsg'.
 280         @param recvdlen Number of bytes received, same as return value of
 281                 userland recvmsg.
 282         @result 0 on success, EWOULDBLOCK if non-blocking and operation
 283                 would cause the thread to block, otherwise the errno error.
 284  */
 285 extern errno_t sock_receive(socket_t so, struct msghdr *msg, int flags,
 286     size_t *recvdlen);
 287
 288 /*!
 289         @function sock_receivembuf
 290         @discussion Receive data from a socket. Similar to sock_receive
 291                 though data is returned as a chain of mbufs. See 'man 2 recvmsg'
 292                 for more information about receiving data.
 293         @param so The socket.
 294         @param msg The msg describing how the data should be received. May
 295                 be NULL. The msg_iov is ignored.
 296         @param data Upon return *data will be a reference to an mbuf chain
 297                 containing the data received. This eliminates copying the data
 298                 out of the mbufs. Caller is responsible for freeing the mbufs.
 299         @param flags See 'man 2 recvmsg'.
 300         @param recvlen Maximum number of bytes to receive in the mbuf chain.
 301                 Upon return, this value will be set to the number of bytes
 302                 received, same as return value of userland recvmsg.
 303         @result 0 on success, EWOULDBLOCK if non-blocking and operation
 304                 would cause the thread to block, otherwise the errno error.
 305  */
 306 extern errno_t sock_receivembuf(socket_t so, struct msghdr *msg, mbuf_t *data,
 307     int flags, size_t *recvlen);
 308
 309 /*!
 310         @function sock_send
 311         @discussion Send data on a socket. Similar to sendmsg. See 'man 2
 312                 sendmsg' for more information about sending data.
 313         @param so The socket.
 314         @param msg The msg describing how the data should be sent. Any
 315                 pointers must point to data in the kernel.
 316         @param flags See 'man 2 sendmsg'.
 317         @param sentlen The number of bytes sent.
 318         @result 0 on success, EWOULDBLOCK if non-blocking and operation
 319                 would cause the thread to block, otherwise the errno error.
 320  */
 321 extern errno_t sock_send(socket_t so, const struct msghdr *msg, int flags,
 322     size_t *sentlen);
 323
 324 /*!
 325         @function sock_sendmbuf
 326         @discussion Send data in an mbuf on a socket. Similar to sock_send
 327                 only the data to be sent is taken from the mbuf chain.
 328         @param so The socket.
 329         @param msg The msg describing how the data should be sent. The
 330                 msg_iov is ignored. msg may be NULL.
 331         @param data The mbuf chain of data to send.
 332         @param flags See 'man 2 sendmsg'.
 333         @param sentlen The number of bytes sent.
 334         @result 0 on success, EWOULDBLOCK if non-blocking and operation
 335                 would cause the thread to block, otherwise the errno error.
 336                 Regardless of return value, the mbuf chain 'data' will be freed.
 337  */
 338 extern errno_t sock_sendmbuf(socket_t so, const struct msghdr *msg, mbuf_t data,
 339     int flags, size_t *sentlen);
 340
 341 /*!
 342         @function sock_shutdown
 343         @discussion Shutdown one or both directions of a connection. See
 344                 'man 2 shutdown' for more information.
 345         @param so The socket.
 346         @param how SHUT_RD - shutdown receive.
 347                 SHUT_WR - shutdown send.
 348                 SHUT_RDWR - shutdown both.
 349         @result 0 on success otherwise the errno error.
 350  */
 351 extern errno_t sock_shutdown(socket_t so, int how);
 352
 353 /*!
 354         @function sock_socket
 355         @discussion Allocate a socket. Allocating a socket in this manner
 356                 creates a socket with no associated file descriptor. For more
 357                 information, see 'man 2 socket'.
 358         @param domain The socket domain (PF_INET, etc...).
 359         @param type The socket type (SOCK_STREAM, SOCK_DGRAM, etc...).
 360         @param protocol The socket protocol.
 361         @param callback A notifier function to be called when an event
 362                 occurs on the socket. This may be NULL.
 363         @param cookie A cookie passed directly to the callback.
 364         @param new_so Upon success, a reference to the new socket.
 365         @result 0 on success otherwise the errno error.
 366  */
 367 extern errno_t sock_socket(int domain, int type, int protocol,
 368     sock_upcall callback, void *cookie, socket_t *new_so);
 369
 370 /*!
 371         @function sock_close
 372         @discussion Close the socket.
 373         @param so The socket to close. This should only ever be a socket
 374                 created with sock_socket. Closing a socket created in user space
 375                 using sock_close may leave a file descriptor pointing to the
 376                 closed socket, resulting in undefined behavior.
 377  */
 378 extern void sock_close(socket_t so);
 379
 380 #ifdef KERNEL_PRIVATE
 381 /*
 382         @function sock_retain
 383         @discussion Prevents the socket from closing
 384         @param so The socket to close.  Increment a retain count on the
 385                 socket, preventing it from being closed when sock_close is
 386                 called. This is used when a File Descriptor is passed (and
 387                 closed) from userland and the kext wants to keep ownership of
 388                 that socket. It is used in conjunction with
 389                 sock_release(socket_t so).
 390  */
 391 extern void sock_retain(socket_t so);
 392
 393 /*
 394         @function sock_release
 395         @discussion Decrement the retain count and close the socket if the
 396                 retain count reaches zero.
 397         @param so The socket to release. This is used to release ownership
 398                 on a socket acquired with sock_retain. When the last retain
 399                 count is reached, this will call sock_close to close the socket.
 400  */
 401 extern void sock_release(socket_t so);
 402 #endif /* KERNEL_PRIVATE */
 403
 404 /*!
 405         @function sock_setpriv
 406         @discussion Set the privileged bit in the socket. Allows for
 407                 operations that require root privileges.
 408         @param so The socket on which to modify the SS_PRIV flag.
 409         @param on Indicate whether or not the SS_PRIV flag should be set.
 410         @result 0 on success otherwise the errno error.
 411  */
 412 extern errno_t sock_setpriv(socket_t so, int on);
 413
 414 /*!
 415         @function sock_isconnected
 416         @discussion Returns whether or not the socket is connected.
 417         @param so The socket to check.
 418         @result 0 - socket is not connected. 1 - socket is connected.
 419  */
 420 extern int sock_isconnected(socket_t so);
 421
 422 /*!
 423         @function sock_isnonblocking
 424         @discussion Returns whether or not the socket is non-blocking. In
 425                 the context of this KPI, non-blocking means that functions to
 426                 perform operations on a socket will not wait for completion.
 427
 428                 To enable or disable blocking, use the FIONBIO ioctl. The
 429                 parameter is an int. If the int is zero, the socket will block.
 430                 If the parameter is non-zero, the socket will not block.
 431         @result 0 - socket will block. 1 - socket will not block.
 432  */
 433 extern int sock_isnonblocking(socket_t so);
 434
 435 /*!
 436         @function sock_gettype
 437         @discussion Retrieves information about the socket. This is the same
 438                 information that was used to create the socket. If any of the
 439                 parameters following so are NULL, that information is not
 440                 retrieved.
 441         @param so The socket to check.
 442         @param domain The domain of the socket (PF_INET, ...). May be NULL.
 443         @param type The socket type (SOCK_STREAM, SOCK_DGRAM, ...). May be NULL.
 444         @param protocol The socket protocol. May be NULL.
 445         @result 0 on success otherwise the errno error.
 446  */
 447 extern errno_t sock_gettype(socket_t so, int *domain, int *type, int *protocol);
 448
 449 #ifdef KERNEL_PRIVATE
 450 /*
 451         @function sock_nointerrupt
 452         @discussion Disables interrupt on socket buffers (sets SB_NOINTR on
 453                 send and receive socket buffers).
 454         @param so The socket to modify.
 455         @param on Indicate whether or not the SB_NOINTR flag should be set.
 456         @result 0 on success otherwise the errno error.
 457  */
 458 extern errno_t sock_nointerrupt(socket_t so, int on);
 459
 460 /*
 461         @function sock_getlistener
 462         @discussion Retrieves the listening socket of a pre-accepted socket,
 463                 i.e. a socket which is still in the incomplete/completed list.
 464                 Once a socket has been accepted, the information pertaining
 465                 to its listener is no longer available.  Therefore, modules
 466                 interested in finding out the listening socket should install
 467                 the appropriate socket filter callback (sf_attach) which gets
 468                 invoked prior to the socket being fully accepted, and call
 469                 this routine at such a time to obtain the listener.  Callers
 470                 are guaranteed that the listener socket will not go away
 471                 during the sf_attach callback, and therefore the value is
 472                 safe to be used only in that callback context.  Callers should
 473                 therefore take note that the listening socket's lock will be
 474                 held throughout the duration of the callback.
 475         @param so The pre-accepted socket.
 476         @result Non-NULL value which indicates the listening socket; otherwise,
 477                 NULL if the socket is not in the incomplete/completed list
 478                 of a listener.
 479  */
 480 extern socket_t sock_getlistener(socket_t so);
 481
 482 /*
 483         @function sock_getaddr
 484         @discussion Retrieves the local or remote address of a socket.
 485                 This is a composite of sock_getpeername and sock_getsockname,
 486                 except that the allocated socket address is returned to the
 487                 caller, and that the caller is reponsible for calling
 488                 sock_freeaddr once finished with it.
 489         @param so The socket.
 490         @param psockname Pointer to the storage for the socket name.
 491         @param peername 0 for local address, and non-zero for peer address.
 492         @result 0 on success otherwise the errno error.
 493  */
 494 extern errno_t sock_getaddr(socket_t so, struct sockaddr **psockname,
 495     int peername);
 496
 497 /*
 498         @function sock_freeaddr
 499         @discussion Frees the socket address allocated by sock_getaddr.
 500         @param sockname The socket name to be freed.
 501  */
 502 extern void sock_freeaddr(struct sockaddr *sockname);
 503
 504 /*
 505         @function sock_setupcall
 506         @discussion Set the notifier function to be called when an event
 507                 occurs on the socket. This may be set to NULL to disable
 508                 further notifications. Setting the function does not
 509                 affect currently notifications about to be sent or being sent.
 510                 Note: When this function is used on a socket passed from
 511                 userspace it is crucial to call sock_retain() on the socket
 512                 otherwise a callback could be dispatched on a closed socket
 513                 and cause a crash.
 514         @param sock The socket.
 515         @param callback The notifier function
 516         @param context A cookie passed directly to the callback
 517 */
 518 extern errno_t sock_setupcall(socket_t sock, sock_upcall callback,
 519     void *context);
 520
 521 /*
 522         @function sock_setupcalls
 523         @discussion Set the notifier function to be called when an event
 524                 occurs on the socket. This may be set to NULL to disable
 525                 further notifications. Setting the function does not
 526                 affect currently notifications about to be sent or being sent.
 527                 Note: When this function is used on a socket passed from
 528                 userspace it is crucial to call sock_retain() on the socket
 529                 otherwise a callback could be dispatched on a closed socket
 530                 and cause a crash.
 531         @param sock The socket.
 532         @param read_callback The read notifier function
 533         @param read_context A cookie passed directly to the read callback
 534         @param write_callback The write notifier function
 535         @param write_context A cookie passed directly to the write callback
 536 */
 537 extern errno_t sock_setupcalls(socket_t sock, sock_upcall read_callback,
 538     void *read_context, sock_upcall write_callback, void *write_context);
 539
 540 /*
 541         @function sock_catchevents
 542         @discussion Set the notifier function to be called when an event
 543                 occurs on the socket. This may be set to NULL to disable
 544                 further notifications. Setting the function does not
 545                 affect currently notifications about to be sent or being sent.
 546         @param sock The socket.
 547         @param event_callback The event notifier function
 548         @param event_context A cookie passed directly to the event callback
 549         @param event_mask One or more SO_FILT_HINT_* values OR'ed together,
 550                 indicating the registered event(s).
 551 */
 552 extern errno_t sock_catchevents(socket_t sock, sock_evupcall event_callback,
 553     void *event_context, u_int32_t event_mask);
 554 /*
 555         @function sock_iskernel
 556         @discussion Returns true if the socket was created by the kernel or
 557                 is owned by the kernel.
 558         @param sock The socket.
 559         @result True if the kernel owns the socket.
 560 */
 561 extern int sock_iskernel(socket_t);
 562 #endif /* KERNEL_PRIVATE */
 563
 564 __END_DECLS
 565 #endif /* __KPI_SOCKET__ */