Reachability.m

/*
 
 
 
 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