fix: fixed wifi support on macOS (fixes pr #1100, fixes #1090, fixes #1076)

network/net_darwin.m

@@ -0,0 +1,72 @@
+#import <Foundation/Foundation.h>
+#import <CoreWLAN/CoreWLAN.h>
+
+// The go side of things expects frequencies.
+int chan2freq(int channel) {
+    if(channel <= 13){ 
+        return ((channel - 1) * 5) + 2412;
+	} else if(channel == 14) {
+		return 2484;
+	} else if(channel <= 173) {
+		return ((channel - 7) * 5) + 5035;
+	} else if(channel == 177) {
+		return 5885;
+	}
+    return 0;
+}
+
+const char *GetSupportedFrequencies(const char *iface) {
+    @autoreleasepool {
+        NSString *interfaceName = [NSString stringWithUTF8String:iface];
+        CWInterface *interface = [CWInterface interfaceWithName:interfaceName];
+        if (!interface) {
+            return NULL;
+        }
+
+        NSSet *supportedChannels = [interface supportedWLANChannels];
+        NSMutableArray *frequencies = [NSMutableArray arrayWithCapacity:[supportedChannels count]];
+
+        for (CWChannel *channel in supportedChannels) {
+            // The go side of things expects frequencies.
+            [frequencies addObject:@(chan2freq(channel.channelNumber))];
+        }   
+
+        NSError *error = nil;
+        NSData *jsonData = [NSJSONSerialization dataWithJSONObject:frequencies options:0 error:&error];
+        if (!jsonData) {
+            NSLog(@"Failed to serialize frequencies: %@", error);
+            return NULL;
+        }
+
+        NSString *jsonString = [[NSString alloc] initWithData:jsonData encoding:NSUTF8StringEncoding];
+        return strdup([jsonString UTF8String]);
+    }
+}
+
+bool SetInterfaceChannel(const char *iface, int channel) {
+    @autoreleasepool {
+        NSString *interfaceName = [NSString stringWithUTF8String:iface];
+        CWInterface *interface = [CWInterface interfaceWithName:interfaceName];
+        if (!interface) {
+            return false;
+        }
+
+        NSError *error = nil;
+        NSSet *supportedChannels = [interface supportedWLANChannels];
+        for (CWChannel * channelObj in supportedChannels) {
+            // it looks like we can't directly build a CWChannel object anymore
+            if ([channelObj channelNumber] == channel) {
+                [interface setWLANChannel:channelObj error:nil];
+                 if (error) {
+                    NSLog(@"Failed to set channel: %@", error);
+                    return false;
+                }
+                return true;
+            }
+        }
+
+        NSLog(@"channel %d not supported", channel);
+
+        return false;
+    }
+}