Configure a pair of connected sockets

OpenVPN Tunnel Provider/OpenVPNAdapter.mm

@@ -6,9 +6,77 @@
 //
 //
 
+#import <sys/socket.h>
+#import <sys/un.h>
+#import <sys/stat.h>
+#import <sys/ioctl.h>
+#import <arpa/inet.h>
+
+#import <NetworkExtension/NetworkExtension.h>
+
+#import "OpenVPNClient.h"
+
 #import "OpenVPNAdapter.h"
+#import "OpenVPNAdapter+Client.h"
+#import "OpenVPNAdapter+Provider.h"
 
 
-@implementation OpenVPNAdapter
+@interface OpenVPNAdapter ()
+
+@property OpenVPNClient *vpnClient;
+
+@property CFSocketRef tunSocket;
+@property CFSocketRef vpnSocket;
+
+@property (weak, nonatomic) NEPacketTunnelFlow *packetFlow;
+
+@end
+
+
+@implementation OpenVPNAdapter (Client)
+
+#pragma mark Sockets Configuration
+
+static void socketCallback(CFSocketRef socket, CFSocketCallBackType type, CFDataRef address, const void *data, void *info) {
+    OpenVPNAdapter *adapter = (__bridge OpenVPNAdapter *)info;
+    
+    switch (type) {
+        case kCFSocketDataCallBack:
+            // TODO: Handle received data and send it to the tun interface
+            break;
+            
+        default:
+            break;
+    }
+}
+
+- (BOOL)configureSockets {
+    int sockets[2];
+    if (socketpair(PF_LOCAL, SOCK_DGRAM, IPPROTO_IP, sockets) == -1) {
+        NSLog(@"Failed to create a pair of connected sockets: %@", [NSString stringWithUTF8String:strerror(errno)]);
+        return NO;
+    }
+    
+    CFSocketContext socketCtxt = {0, (__bridge void *)self, NULL, NULL, NULL};
+    
+    self.tunSocket = CFSocketCreateWithNative(kCFAllocatorDefault, sockets[0], kCFSocketDataCallBack, &socketCallback, &socketCtxt);
+    self.vpnSocket = CFSocketCreateWithNative(kCFAllocatorDefault, sockets[1], kCFSocketNoCallBack, NULL, NULL);
+    
+    if (!self.tunSocket || !self.vpnSocket) {
+        NSLog(@"Failed to create core foundation sockets from native sockets");
+        return NO;
+    }
+    
+    CFRunLoopSourceRef tunSocketSource = CFSocketCreateRunLoopSource(kCFAllocatorDefault, self.tunSocket, 0);
+    CFRunLoopAddSource(CFRunLoopGetMain(), tunSocketSource, kCFRunLoopCommonModes);
+    
+    CFRelease(tunSocketSource);
+    
+    return YES;
+}
+
+@end
+
+@implementation OpenVPNAdapter (Provider)
 
 @end