1 /*
2
3 File: Reachability.m
4 Abstract: Basic demonstration of how to use the SystemConfiguration Reachablity APIs.
5
6 Version: 2.2
7
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44 Copyright (C) 2010 Apple Inc. All Rights Reserved.
45
46 */
47
48 #import <sys/socket.h>
49 #import <netinet/in.h>
50 #import <netinet6/in6.h>
51 #import <arpa/inet.h>
52 #import <ifaddrs.h>
53 #import <netdb.h>
54
55 #import <CoreFoundation/CoreFoundation.h>
56
57 #import "Reachability.h"
58
59 #define kShouldPrintReachabilityFlags 1
60
61 static void PrintReachabilityFlags(SCNetworkReachabilityFlags flags, const char* comment)
62 {
63 #if kShouldPrintReachabilityFlags
64
65 NSLog(@"Reachability Flag Status: %c%c %c%c%c%c%c%c%c %s\n",
66 (flags & kSCNetworkReachabilityFlagsIsWWAN) ? 'W' : '-',
67 (flags & kSCNetworkReachabilityFlagsReachable) ? 'R' : '-',
68
69 (flags & kSCNetworkReachabilityFlagsTransientConnection) ? 't' : '-',
70 (flags & kSCNetworkReachabilityFlagsConnectionRequired) ? 'c' : '-',
71 (flags & kSCNetworkReachabilityFlagsConnectionOnTraffic) ? 'C' : '-',
72 (flags & kSCNetworkReachabilityFlagsInterventionRequired) ? 'i' : '-',
73 (flags & kSCNetworkReachabilityFlagsConnectionOnDemand) ? 'D' : '-',
74 (flags & kSCNetworkReachabilityFlagsIsLocalAddress) ? 'l' : '-',
75 (flags & kSCNetworkReachabilityFlagsIsDirect) ? 'd' : '-',
76 comment
77 );
78 #endif
79 }
80
81
82 @implementation Reachability
83 static void ReachabilityCallback(SCNetworkReachabilityRef target, SCNetworkReachabilityFlags flags, void* info)
84 {
85 #pragma unused (target, flags)
86 NSCAssert(info != NULL, @"info was NULL in ReachabilityCallback");
87 NSCAssert([(NSObject*) info isKindOfClass: [Reachability class]], @"info was wrong class in ReachabilityCallback");
88
89 //We're on the main RunLoop, so an NSAutoreleasePool is not necessary, but is added defensively
90 // in case someon uses the Reachablity object in a different thread.
91 NSAutoreleasePool* myPool = [[NSAutoreleasePool alloc] init];
92
93 Reachability* noteObject = (Reachability*) info;
94 // Post a notification to notify the client that the network reachability changed.
95 [[NSNotificationCenter defaultCenter] postNotificationName: kReachabilityChangedNotification object: noteObject];
96
97 [myPool release];
98 }
99
100 - (BOOL) startNotifier
101 {
102 BOOL retVal = NO;
103 SCNetworkReachabilityContext context = {0, self, NULL, NULL, NULL};
104 if(SCNetworkReachabilitySetCallback(reachabilityRef, ReachabilityCallback, &context))
105 {
106 if(SCNetworkReachabilityScheduleWithRunLoop(reachabilityRef, CFRunLoopGetCurrent(), kCFRunLoopDefaultMode))
107 {
108 retVal = YES;
109 }
110 }
111 return retVal;
112 }
113
114 - (void) stopNotifier
115 {
116 if(reachabilityRef!= NULL)
117 {
118 SCNetworkReachabilityUnscheduleFromRunLoop(reachabilityRef, CFRunLoopGetCurrent(), kCFRunLoopDefaultMode);
119 }
120 }
121
122 - (void) dealloc
123 {
124 [self stopNotifier];
125 if(reachabilityRef!= NULL)
126 {
127 CFRelease(reachabilityRef);
128 }
129 [super dealloc];
130 }
131
132 + (Reachability*) reachabilityWithHostName: (NSString*) hostName;
133 {
134 Reachability* retVal = NULL;
135 SCNetworkReachabilityRef reachability = SCNetworkReachabilityCreateWithName(NULL, [hostName UTF8String]);
136 if(reachability!= NULL)
137 {
138 retVal= [[[self alloc] init] autorelease];
139 if(retVal!= NULL)
140 {
141 retVal->reachabilityRef = reachability;
142 retVal->localWiFiRef = NO;
143 }
144 }
145 return retVal;
146 }
147
148 + (Reachability*) reachabilityWithAddress: (const struct sockaddr_in*) hostAddress;
149 {
150 SCNetworkReachabilityRef reachability = SCNetworkReachabilityCreateWithAddress(kCFAllocatorDefault, (const struct sockaddr*)hostAddress);
151 Reachability* retVal = NULL;
152 if(reachability!= NULL)
153 {
154 retVal= [[[self alloc] init] autorelease];
155 if(retVal!= NULL)
156 {
157 retVal->reachabilityRef = reachability;
158 retVal->localWiFiRef = NO;
159 }
160 }
161 return retVal;
162 }
163
164 + (Reachability*) reachabilityForInternetConnection;
165 {
166 struct sockaddr_in zeroAddress;
167 bzero(&zeroAddress, sizeof(zeroAddress));
168 zeroAddress.sin_len = sizeof(zeroAddress);
169 zeroAddress.sin_family = AF_INET;
170 return [self reachabilityWithAddress: &zeroAddress];
171 }
172
173 + (Reachability*) reachabilityForLocalWiFi;
174 {
175 struct sockaddr_in localWifiAddress;
176 bzero(&localWifiAddress, sizeof(localWifiAddress));
177 localWifiAddress.sin_len = sizeof(localWifiAddress);
178 localWifiAddress.sin_family = AF_INET;
179 // IN_LINKLOCALNETNUM is defined in <netinet/in.h> as 169.254.0.0
180 localWifiAddress.sin_addr.s_addr = htonl(IN_LINKLOCALNETNUM);
181 Reachability* retVal = [self reachabilityWithAddress: &localWifiAddress];
182 if(retVal!= NULL)
183 {
184 retVal->localWiFiRef = YES;
185 }
186 return retVal;
187 }
188
189 #pragma mark Network Flag Handling
190
191 - (NetworkStatus) localWiFiStatusForFlags: (SCNetworkReachabilityFlags) flags
192 {
193 PrintReachabilityFlags(flags, "localWiFiStatusForFlags");
194
195 BOOL retVal = NotReachable;
196 if((flags & kSCNetworkReachabilityFlagsReachable) && (flags & kSCNetworkReachabilityFlagsIsDirect))
197 {
198 retVal = ReachableViaWiFi;
199 }
200 return retVal;
201 }
202
203 - (NetworkStatus) networkStatusForFlags: (SCNetworkReachabilityFlags) flags
204 {
205 PrintReachabilityFlags(flags, "networkStatusForFlags");
206 if ((flags & kSCNetworkReachabilityFlagsReachable) == 0)
207 {
208 // if target host is not reachable
209 return NotReachable;
210 }
211
212 BOOL retVal = NotReachable;
213
214 if ((flags & kSCNetworkReachabilityFlagsConnectionRequired) == 0)
215 {
216 // if target host is reachable and no connection is required
217 // then we'll assume (for now) that your on Wi-Fi
218 retVal = ReachableViaWiFi;
219 }
220
221
222 if ((((flags & kSCNetworkReachabilityFlagsConnectionOnDemand ) != 0) ||
223 (flags & kSCNetworkReachabilityFlagsConnectionOnTraffic) != 0))
224 {
225 // ... and the connection is on-demand (or on-traffic) if the
226 // calling application is using the CFSocketStream or higher APIs
227
228 if ((flags & kSCNetworkReachabilityFlagsInterventionRequired) == 0)
229 {
230 // ... and no [user] intervention is needed
231 retVal = ReachableViaWiFi;
232 }
233 }
234
235 if ((flags & kSCNetworkReachabilityFlagsIsWWAN) == kSCNetworkReachabilityFlagsIsWWAN)
236 {
237 // ... but WWAN connections are OK if the calling application
238 // is using the CFNetwork (CFSocketStream?) APIs.
239 retVal = ReachableViaWWAN;
240 }
241 return retVal;
242 }
243
244 - (BOOL) connectionRequired;
245 {
246 NSAssert(reachabilityRef != NULL, @"connectionRequired called with NULL reachabilityRef");
247 SCNetworkReachabilityFlags flags;
248 if (SCNetworkReachabilityGetFlags(reachabilityRef, &flags))
249 {
250 return (flags & kSCNetworkReachabilityFlagsConnectionRequired);
251 }
252 return NO;
253 }
254
255 - (NetworkStatus) currentReachabilityStatus
256 {
257 NSAssert(reachabilityRef != NULL, @"currentNetworkStatus called with NULL reachabilityRef");
258 NetworkStatus retVal = NotReachable;
259 SCNetworkReachabilityFlags flags;
260 if (SCNetworkReachabilityGetFlags(reachabilityRef, &flags))
261 {
262 if(localWiFiRef)
263 {
264 retVal = [self localWiFiStatusForFlags: flags];
265 }
266 else
267 {
268 retVal = [self networkStatusForFlags: flags];
269 }
270 }
271 return retVal;
272 }
273 @end
