/*

 File: Reachability.m

 Abstract: Basic demonstration of how to use the SystemConfiguration Reachablity APIs.

 Version: 2.2

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*/

#import <sys/socket.h>

#import <netinet/in.h>

#import <netinet6/in6.h>

#import <arpa/inet.h>

#import <ifaddrs.h>

#import <netdb.h>

#import <CoreFoundation/CoreFoundation.h>

#import "Reachability.h"

#define kShouldPrintReachabilityFlags 1

static void PrintReachabilityFlags(SCNetworkReachabilityFlags flags, const char *comment)

{

#if kShouldPrintReachabilityFlags

	NSLog(@"Reachability Flag Status: %c%c %c%c%c%c%c%c%c %s\n",

	      (flags & kSCNetworkReachabilityFlagsIsWWAN) ? 'W' : '-',

	      (flags & kSCNetworkReachabilityFlagsReachable) ? 'R' : '-',

	      (flags & kSCNetworkReachabilityFlagsTransientConnection) ? 't' : '-',

	      (flags & kSCNetworkReachabilityFlagsConnectionRequired) ? 'c' : '-',

	      (flags & kSCNetworkReachabilityFlagsConnectionOnTraffic) ? 'C' : '-',

	      (flags & kSCNetworkReachabilityFlagsInterventionRequired) ? 'i' : '-',

	      (flags & kSCNetworkReachabilityFlagsConnectionOnDemand) ? 'D' : '-',

	      (flags & kSCNetworkReachabilityFlagsIsLocalAddress) ? 'l' : '-',

	      (flags & kSCNetworkReachabilityFlagsIsDirect) ? 'd' : '-', comment);

#endif

}

@implementation Reachability

static void ReachabilityCallback(SCNetworkReachabilityRef target, SCNetworkReachabilityFlags flags,

                                 void *info)

{

#pragma unused(target, flags)

	NSCAssert(info != NULL, @"info was NULL in ReachabilityCallback");

	NSCAssert([(NSObject *)info isKindOfClass:[Reachability class]],

	          @"info was wrong class in ReachabilityCallback");

	// We're on the main RunLoop, so an NSAutoreleasePool is not necessary, but is added defensively

	// in case someon uses the Reachablity object in a different thread.

	NSAutoreleasePool *myPool = [[NSAutoreleasePool alloc] init];

	Reachability *noteObject = (Reachability *)info;

	// Post a notification to notify the client that the network reachability changed.

	[[NSNotificationCenter defaultCenter] postNotificationName:kReachabilityChangedNotification

	                                                    object:noteObject];

	[myPool release];

}

- (BOOL)startNotifier

{

	BOOL retVal = NO;

	SCNetworkReachabilityContext context = { 0, self, NULL, NULL, NULL };

	if (SCNetworkReachabilitySetCallback(reachabilityRef, ReachabilityCallback, &context))

	{

		if (SCNetworkReachabilityScheduleWithRunLoop(reachabilityRef, CFRunLoopGetCurrent(),

		                                             kCFRunLoopDefaultMode))

		{

			retVal = YES;

		}

	}

	return retVal;

}

- (void)stopNotifier

{

	if (reachabilityRef != NULL)

	{

		SCNetworkReachabilityUnscheduleFromRunLoop(reachabilityRef, CFRunLoopGetCurrent(),

		                                           kCFRunLoopDefaultMode);

	}

}

- (void)dealloc

{

	[self stopNotifier];

	if (reachabilityRef != NULL)

	{

		CFRelease(reachabilityRef);

	}

	[super dealloc];

}

+ (Reachability *)reachabilityWithHostName:(NSString *)hostName;

{

	Reachability *retVal = NULL;

	SCNetworkReachabilityRef reachability =

	    SCNetworkReachabilityCreateWithName(NULL, [hostName UTF8String]);

	if (reachability != NULL)

	{

		retVal = [[[self alloc] init] autorelease];

		if (retVal != NULL)

		{

			retVal->reachabilityRef = reachability;

			retVal->localWiFiRef = NO;

		}

	}

	return retVal;

}

+ (Reachability *)reachabilityWithAddress:(const struct sockaddr_in *)hostAddress;

{

	SCNetworkReachabilityRef reachability = SCNetworkReachabilityCreateWithAddress(

	    kCFAllocatorDefault, (const struct sockaddr *)hostAddress);

	Reachability *retVal = NULL;

	if (reachability != NULL)

	{

		retVal = [[[self alloc] init] autorelease];

		if (retVal != NULL)

		{

			retVal->reachabilityRef = reachability;

			retVal->localWiFiRef = NO;

		}

	}

	return retVal;

}

+ (Reachability *)reachabilityForInternetConnection;

{

	struct sockaddr_in zeroAddress;

	bzero(&zeroAddress, sizeof(zeroAddress));

	zeroAddress.sin_len = sizeof(zeroAddress);

	zeroAddress.sin_family = AF_INET;

	return [self reachabilityWithAddress:&zeroAddress];

}

+ (Reachability *)reachabilityForLocalWiFi;

{

	struct sockaddr_in localWifiAddress;

	bzero(&localWifiAddress, sizeof(localWifiAddress));

	localWifiAddress.sin_len = sizeof(localWifiAddress);

	localWifiAddress.sin_family = AF_INET;

	// IN_LINKLOCALNETNUM is defined in <netinet/in.h> as 169.254.0.0

	localWifiAddress.sin_addr.s_addr = htonl(IN_LINKLOCALNETNUM);

	Reachability *retVal = [self reachabilityWithAddress:&localWifiAddress];

	if (retVal != NULL)

	{

		retVal->localWiFiRef = YES;

	}

	return retVal;

}

#pragma mark Network Flag Handling

- (NetworkStatus)localWiFiStatusForFlags:(SCNetworkReachabilityFlags)flags

{

	PrintReachabilityFlags(flags, "localWiFiStatusForFlags");

	BOOL retVal = NotReachable;

	if ((flags & kSCNetworkReachabilityFlagsReachable) &&

	    (flags & kSCNetworkReachabilityFlagsIsDirect))

	{

		retVal = ReachableViaWiFi;

	}

	return retVal;

}

- (NetworkStatus)networkStatusForFlags:(SCNetworkReachabilityFlags)flags

{

	PrintReachabilityFlags(flags, "networkStatusForFlags");

	if ((flags & kSCNetworkReachabilityFlagsReachable) == 0)

	{

		// if target host is not reachable

		return NotReachable;

	}

	BOOL retVal = NotReachable;

	if ((flags & kSCNetworkReachabilityFlagsConnectionRequired) == 0)

	{

		// if target host is reachable and no connection is required

		//  then we'll assume (for now) that your on Wi-Fi

		retVal = ReachableViaWiFi;

	}

	if ((((flags & kSCNetworkReachabilityFlagsConnectionOnDemand) != 0) ||

	     (flags & kSCNetworkReachabilityFlagsConnectionOnTraffic) != 0))

	{

		// ... and the connection is on-demand (or on-traffic) if the

		//     calling application is using the CFSocketStream or higher APIs

		if ((flags & kSCNetworkReachabilityFlagsInterventionRequired) == 0)

		{

			// ... and no [user] intervention is needed

			retVal = ReachableViaWiFi;

		}

	}

	if ((flags & kSCNetworkReachabilityFlagsIsWWAN) == kSCNetworkReachabilityFlagsIsWWAN)

	{

		// ... but WWAN connections are OK if the calling application

		//     is using the CFNetwork (CFSocketStream?) APIs.

		retVal = ReachableViaWWAN;

	}

	return retVal;

}

- (BOOL)connectionRequired;

{

	NSAssert(reachabilityRef != NULL, @"connectionRequired called with NULL reachabilityRef");

	SCNetworkReachabilityFlags flags;

	if (SCNetworkReachabilityGetFlags(reachabilityRef, &flags))

	{

		return (flags & kSCNetworkReachabilityFlagsConnectionRequired);

	}

	return NO;

}

- (NetworkStatus)currentReachabilityStatus

{

	NSAssert(reachabilityRef != NULL, @"currentNetworkStatus called with NULL reachabilityRef");

	NetworkStatus retVal = NotReachable;

	SCNetworkReachabilityFlags flags;

	if (SCNetworkReachabilityGetFlags(reachabilityRef, &flags))

	{

		if (localWiFiRef)

		{

			retVal = [self localWiFiStatusForFlags:flags];

		}

		else

		{

			retVal = [self networkStatusForFlags:flags];

		}

	}

	return retVal;

}

@end