SystemConfiguration.fproj/SCNetworkReachability.h

   1 /*
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  23
  24 #ifndef _SCNETWORKREACHABILITY_H
  25 #define _SCNETWORKREACHABILITY_H
  26
  27 #include <os/availability.h>
  28 #include <TargetConditionals.h>
  29 #include <sys/cdefs.h>
  30 #include <sys/types.h>
  31 #include <sys/socket.h>
  32 #include <CoreFoundation/CoreFoundation.h>
  33 #include <SystemConfiguration/SCNetwork.h>
  34 #include <dispatch/dispatch.h>
  35
  36 CF_IMPLICIT_BRIDGING_ENABLED
  37 CF_ASSUME_NONNULL_BEGIN
  38
  39 /*!
  40         @header SCNetworkReachability
  41         @discussion The SCNetworkReachability API allows an application to
  42                 determine the status of a system's current network
  43                 configuration and the reachability of a target host.
  44                 In addition, reachability can be monitored with notifications
  45                 that are sent when the status has changed.
  46
  47                 "Reachability" reflects whether a data packet, sent by
  48                 an application into the network stack, can leave the local
  49                 computer.
  50                 Note that reachability does <i>not</i> guarantee that the data
  51                 packet will actually be received by the host.
  52
  53                 When reachability is used without scheduling updates on a runloop
  54                 or dispatch queue, the system will not generate DNS traffic and
  55                 will be optimistic about its reply - it will assume that the target
  56                 is reachable if there is a default route but a DNS query is
  57                 needed to learn the address. When scheduled, the first callback
  58                 will behave like an unscheduled call but subsequent calls will
  59                 leverage DNS results.
  60
  61                 When used on IPv6-only (NAT64+DNS64) networks, reachability checks
  62                 for IPv4 address literals (either a struct sockaddr_in * or textual
  63                 representations such as "192.0.2.1") will automatically give the
  64                 result for the corresponding synthesized IPv6 address.
  65                 On those networks, creating a CFSocketStream or NSURLSession
  66                 to that address will send packets but trying to connect using
  67                 BSD socket APIs will fail.
  68  */
  69
  70 /*!
  71         @typedef SCNetworkReachabilityRef
  72         @discussion This is the handle to a network address or name.
  73  */
  74 typedef const struct CF_BRIDGED_TYPE(id) __SCNetworkReachability * SCNetworkReachabilityRef;
  75
  76
  77 /*!
  78         @typedef SCNetworkReachabilityContext
  79         Structure containing user-specified data and callbacks for SCNetworkReachability.
  80         @field version The version number of the structure type being passed
  81                 in as a parameter to the SCDynamicStore creation function.
  82                 This structure is version 0.
  83         @field info A C pointer to a user-specified block of data.
  84         @field retain The callback used to add a retain for the info field.
  85                 If this parameter is not a pointer to a function of the correct
  86                 prototype, the behavior is undefined.  The value may be NULL.
  87         @field release The calllback used to remove a retain previously added
  88                 for the info field.  If this parameter is not a pointer to a
  89                 function of the correct prototype, the behavior is undefined.
  90                 The value may be NULL.
  91         @field copyDescription The callback used to provide a description of
  92                 the info field.
  93  */
  94 typedef struct {
  95         CFIndex         version;
  96         void *          __nullable info;
  97         const void      * __nonnull (* __nullable retain)(const void *info);
  98         void            (* __nullable release)(const void *info);
  99         CFStringRef     __nonnull (* __nullable copyDescription)(const void *info);
 100 } SCNetworkReachabilityContext;
 101
 102 /*!
 103         @enum SCNetworkReachabilityFlags
 104         @discussion Flags that indicate whether the specified network
 105                 nodename or address is reachable, whether a connection is
 106                 required, and whether some user intervention may be required
 107                 when establishing a connection.
 108         @constant kSCNetworkReachabilityFlagsTransientConnection
 109                 This flag indicates that the specified nodename or address can
 110                 be reached via a transient connection, such as PPP.
 111         @constant kSCNetworkReachabilityFlagsReachable
 112                 This flag indicates that the specified nodename or address can
 113                 be reached using the current network configuration.
 114         @constant kSCNetworkReachabilityFlagsConnectionRequired
 115                 This flag indicates that the specified nodename or address can
 116                 be reached using the current network configuration, but a
 117                 connection must first be established.
 118
 119                 As an example, this status would be returned for a dialup
 120                 connection that was not currently active, but could handle
 121                 network traffic for the target system.
 122         @constant kSCNetworkReachabilityFlagsConnectionOnTraffic
 123                 This flag indicates that the specified nodename or address can
 124                 be reached using the current network configuration, but a
 125                 connection must first be established.  Any traffic directed
 126                 to the specified name or address will initiate the connection.
 127
 128                 Note: this flag was previously named kSCNetworkReachabilityFlagsConnectionAutomatic
 129         @constant kSCNetworkReachabilityFlagsInterventionRequired
 130                 This flag indicates that the specified nodename or address can
 131                 be reached using the current network configuration, but a
 132                 connection must first be established.  In addition, some
 133                 form of user intervention will be required to establish this
 134                 connection, such as providing a password, an authentication
 135                 token, etc.
 136
 137                 Note: At the present time, this flag will only be returned
 138                 in the case where you have a dial-on-traffic configuration
 139                 (ConnectionOnTraffic), where an attempt to connect has
 140                 already been made, and where some error (e.g. no dial tone,
 141                 no answer, bad password, ...) was encountered during the
 142                 automatic connection attempt.  In this case the PPP controller
 143                 will stop attempting to establish a connection until the user
 144                 has intervened.
 145         @constant kSCNetworkReachabilityFlagsConnectionOnDemand
 146                 This flag indicates that the specified nodename or address can
 147                 be reached using the current network configuration, but a
 148                 connection must first be established.
 149                 The connection will be established "On Demand" by the
 150                 CFSocketStream APIs.
 151                 Other APIs will not establish the connection.
 152         @constant kSCNetworkReachabilityFlagsIsLocalAddress
 153                 This flag indicates that the specified nodename or address
 154                 is one associated with a network interface on the current
 155                 system.
 156         @constant kSCNetworkReachabilityFlagsIsDirect
 157                 This flag indicates that network traffic to the specified
 158                 nodename or address will not go through a gateway, but is
 159                 routed directly to one of the interfaces in the system.
 160         @constant kSCNetworkReachabilityFlagsIsWWAN
 161                 This flag indicates that the specified nodename or address can
 162                 be reached via an EDGE, GPRS, or other "cell" connection.
 163  */
 164 typedef CF_OPTIONS(uint32_t, SCNetworkReachabilityFlags) {
 165         kSCNetworkReachabilityFlagsTransientConnection          = 1<<0,
 166         kSCNetworkReachabilityFlagsReachable                    = 1<<1,
 167         kSCNetworkReachabilityFlagsConnectionRequired           = 1<<2,
 168         kSCNetworkReachabilityFlagsConnectionOnTraffic          = 1<<3,
 169         kSCNetworkReachabilityFlagsInterventionRequired         = 1<<4,
 170         kSCNetworkReachabilityFlagsConnectionOnDemand
 171                 API_AVAILABLE(macos(6.0),ios(3.0))              = 1<<5,
 172         kSCNetworkReachabilityFlagsIsLocalAddress               = 1<<16,
 173         kSCNetworkReachabilityFlagsIsDirect                     = 1<<17,
 174         kSCNetworkReachabilityFlagsIsWWAN
 175                 API_UNAVAILABLE(macos) API_AVAILABLE(ios(2.0))  = 1<<18,
 176
 177         kSCNetworkReachabilityFlagsConnectionAutomatic  = kSCNetworkReachabilityFlagsConnectionOnTraffic
 178 };
 179
 180 /*!
 181         @typedef SCNetworkReachabilityCallBack
 182         @discussion Type of the callback function used when the
 183                 reachability of a network address or name changes.
 184         @param target The SCNetworkReachability reference being monitored
 185                 for changes.
 186         @param flags The new SCNetworkReachabilityFlags representing the
 187                 reachability status of the network address/name.
 188         @param info A C pointer to a user-specified block of data.
 189  */
 190 typedef void (*SCNetworkReachabilityCallBack)   (
 191                                                 SCNetworkReachabilityRef                        target,
 192                                                 SCNetworkReachabilityFlags                      flags,
 193                                                 void                         *  __nullable      info
 194                                                 );
 195
 196 __BEGIN_DECLS
 197
 198 /*!
 199         @function SCNetworkReachabilityCreateWithAddress
 200         @discussion Creates a reference to the specified network
 201                 address.  This reference can be used later to monitor the
 202                 reachability of the target host.
 203         @param address The address of the desired host.
 204         @result Returns a reference to the new immutable SCNetworkReachabilityRef.
 205
 206                  You must release the returned value.
 207  */
 208 SCNetworkReachabilityRef __nullable
 209 SCNetworkReachabilityCreateWithAddress          (
 210                                                 CFAllocatorRef                  __nullable      allocator,
 211                                                 const struct sockaddr                           *address
 212                                                 )                               API_AVAILABLE(macos(10.3), ios(2.0));
 213
 214 /*!
 215         @function SCNetworkReachabilityCreateWithAddressPair
 216         @discussion Creates a reference to the specified network
 217                 address.  This reference can be used later to monitor the
 218                 reachability of the target host.
 219         @param localAddress The local address associated with a network
 220                 connection.  If NULL, only the remote address is of interest.
 221         @param remoteAddress The remote address associated with a network
 222                 connection.  If NULL, only the local address is of interest.
 223         @result Returns a reference to the new immutable SCNetworkReachabilityRef.
 224
 225                  You must release the returned value.
 226  */
 227 SCNetworkReachabilityRef __nullable
 228 SCNetworkReachabilityCreateWithAddressPair      (
 229                                                 CFAllocatorRef                  __nullable      allocator,
 230                                                 const struct sockaddr           * __nullable    localAddress,
 231                                                 const struct sockaddr           * __nullable    remoteAddress
 232                                                 )                               API_AVAILABLE(macos(10.3), ios(2.0));
 233
 234 /*!
 235         @function SCNetworkReachabilityCreateWithName
 236         @discussion Creates a reference to the specified network host or node
 237                 name.  This reference can be used later to monitor the
 238                 reachability of the target host.
 239         @param nodename The node name of the desired host.
 240                 This name would be the same as that passed to the
 241                 gethostbyname(3) or getaddrinfo(3) functions.
 242         @result Returns a reference to the new immutable SCNetworkReachabilityRef.
 243
 244                 You must release the returned value.
 245  */
 246 SCNetworkReachabilityRef __nullable
 247 SCNetworkReachabilityCreateWithName             (
 248                                                 CFAllocatorRef                  __nullable      allocator,
 249                                                 const char                                      *nodename
 250                                                 )                               API_AVAILABLE(macos(10.3), ios(2.0));
 251
 252 /*!
 253         @function SCNetworkReachabilityGetTypeID
 254         @discussion Returns the type identifier of all SCNetworkReachability
 255                 instances.
 256  */
 257 CFTypeID
 258 SCNetworkReachabilityGetTypeID                  (void)                          API_AVAILABLE(macos(10.3), ios(2.0));
 259
 260
 261 /*!
 262         @function SCNetworkReachabilityGetFlags
 263         @discussion Determines if the given target is reachable using the
 264                 current network configuration.
 265         @param target The network reference associated with the address or name
 266                 to be checked for reachability.
 267         @param flags A pointer to memory that will be filled with the
 268                 SCNetworkReachabilityFlags detailing the reachability
 269                 of the specified target.
 270         @result Returns TRUE if the network connection flags are valid;
 271                 FALSE if the status could not be determined.
 272  */
 273 Boolean
 274 SCNetworkReachabilityGetFlags                   (
 275                                                 SCNetworkReachabilityRef        target,
 276                                                 SCNetworkReachabilityFlags      *flags
 277                                                 )                               API_AVAILABLE(macos(10.3), ios(2.0));
 278
 279 /*!
 280         @function SCNetworkReachabilitySetCallback
 281         @discussion Assigns a client to a target, which receives callbacks
 282                 when the reachability of the target changes.
 283         @param target The network reference associated with the address or
 284                 name to be checked for reachability.
 285         @param callout The function to be called when the reachability of the
 286                 target changes.  If NULL, the current client for the target
 287                 is removed.
 288         @param context The SCNetworkReachabilityContext associated with
 289                 the callout.  The value may be NULL.
 290         @result Returns TRUE if the notification client was successfully set.
 291  */
 292 Boolean
 293 SCNetworkReachabilitySetCallback                (
 294                                                 SCNetworkReachabilityRef                        target,
 295                                                 SCNetworkReachabilityCallBack   __nullable      callout,
 296                                                 SCNetworkReachabilityContext    * __nullable    context
 297                                                 )                               API_AVAILABLE(macos(10.3), ios(2.0));
 298
 299 /*!
 300         @function SCNetworkReachabilityScheduleWithRunLoop
 301         @discussion Schedules the given target with the given run loop and mode.
 302         @param target The address or name that is set up for asynchronous
 303                 notifications.  Must be non-NULL.
 304         @param runLoop A reference to a run loop on which the target should
 305                 be scheduled.  Must be non-NULL.
 306         @param runLoopMode The mode on which to schedule the target.
 307                 Must be non-NULL.
 308         @result Returns TRUE if the target is scheduled successfully;
 309                 FALSE otherwise.
 310  */
 311 Boolean
 312 SCNetworkReachabilityScheduleWithRunLoop        (
 313                                                 SCNetworkReachabilityRef        target,
 314                                                 CFRunLoopRef                    runLoop,
 315                                                 CFStringRef                     runLoopMode
 316                                                 )                               API_AVAILABLE(macos(10.3), ios(2.0));
 317
 318 /*!
 319         @function SCNetworkReachabilityUnscheduleFromRunLoop
 320         @discussion Unschedules the given target from the given run loop
 321                 and mode.
 322         @param target The address or name that is set up for asynchronous
 323                 notifications.  Must be non-NULL.
 324         @param runLoop A reference to a run loop from which the target
 325                 should be unscheduled.  Must be non-NULL.
 326         @param runLoopMode The mode on which to unschedule the target.
 327                 Must be non-NULL.
 328         @result Returns TRUE if the target is unscheduled successfully;
 329                 FALSE otherwise.
 330  */
 331 Boolean
 332 SCNetworkReachabilityUnscheduleFromRunLoop      (
 333                                                 SCNetworkReachabilityRef        target,
 334                                                 CFRunLoopRef                    runLoop,
 335                                                 CFStringRef                     runLoopMode
 336                                                 )                               API_AVAILABLE(macos(10.3), ios(2.0));
 337
 338 /*!
 339         @function SCNetworkReachabilitySetDispatchQueue
 340         @discussion Schedule or unschedule callbacks for the given target on the given
 341                 dispatch queue.
 342         @param target The address or name that is set up for asynchronous
 343                 notifications.  Must be non-NULL.
 344         @param queue A libdispatch queue to run the callback on.
 345                 Pass NULL to unschedule callbacks.
 346         @result Returns TRUE if the target is scheduled or unscheduled successfully;
 347                 FALSE otherwise.
 348  */
 349 Boolean
 350 SCNetworkReachabilitySetDispatchQueue           (
 351                                                 SCNetworkReachabilityRef                        target,
 352                                                 dispatch_queue_t                __nullable      queue
 353                                                 )                               API_AVAILABLE(macos(10.6), ios(4.0));
 354
 355 __END_DECLS
 356
 357 CF_ASSUME_NONNULL_END
 358 CF_IMPLICIT_BRIDGING_DISABLED
 359
 360 #endif  /* _SCNETWORKREACHABILITY_H */