/*

 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