Add OpenVPNNetworkSettingsBuilder

Add OpenVPNPacketFlowAdapter
2026-04-24 00:00:05 +08:00 · 2017-10-12 13:06:25 +01:00
parent 3bb4ff773a
commit f5c85fcb12
6 changed files with 549 additions and 399 deletions
@@ -0,0 +1,179 @@
+//
+//  OpenVPNPacketFlowAdapter.mm
+//  OpenVPN Adapter
+//
+//  Created by Jonathan Downing on 12/10/2017.
+//
+
+#import "OpenVPNPacketFlowAdapter.h"
+#import <NetworkExtension/NetworkExtension.h>
+#import <openvpn/ip/ip.hpp>
+
+@interface OpenVPNPacketFlowAdapter () {
+    CFSocketRef _openVPNClientSocket;
+    CFSocketRef _packetFlowSocket;
+}
+@property (nonatomic) NEPacketTunnelFlow *packetFlow;
+@end
+
+@implementation OpenVPNPacketFlowAdapter
+
+- (instancetype)initWithPacketFlow:(NEPacketTunnelFlow *)packetFlow {
+    if ((self = [super init])) {
+        self.packetFlow = packetFlow;
+        
+        if (![self configureSockets]) {
+            return nil;
+        }
+        
+        [self readPacketFlowPackets];
+    }
+    return self;
+}
+
+- (CFSocketNativeHandle)socketHandle {
+    return CFSocketGetNative(_openVPNClientSocket);
+}
+
+static inline void PacketFlowSocketCallback(CFSocketRef socket, CFSocketCallBackType type, CFDataRef address, const void *data, void *info) {
+    if (type == kCFSocketDataCallBack) {
+        [(__bridge OpenVPNPacketFlowAdapter *)info writeDataToPacketFlow:(__bridge NSData *)data];
+    }
+}
+
+- (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;
+    }
+    
+    if (![self configureBufferSizeForSocket:sockets[0]] || ![self configureBufferSizeForSocket:sockets[1]]) {
+        NSLog(@"Failed to configure buffer size of the sockets");
+        return NO;
+    }
+    
+    CFSocketContext socketCtxt = {0, (__bridge void *)self, NULL, NULL, NULL};
+    
+    _packetFlowSocket = CFSocketCreateWithNative(kCFAllocatorDefault, sockets[0], kCFSocketDataCallBack, PacketFlowSocketCallback, &socketCtxt);
+    _openVPNClientSocket = CFSocketCreateWithNative(kCFAllocatorDefault, sockets[1], kCFSocketNoCallBack, NULL, NULL);
+    
+    if (!_packetFlowSocket || !_openVPNClientSocket) {
+        NSLog(@"Failed to create core foundation sockets from native sockets");
+        return NO;
+    }
+    
+    CFRunLoopSourceRef packetFlowSocketSource = CFSocketCreateRunLoopSource(kCFAllocatorDefault, _packetFlowSocket, 0);
+    CFRunLoopAddSource(CFRunLoopGetMain(), packetFlowSocketSource, kCFRunLoopDefaultMode);
+    CFRelease(packetFlowSocketSource);
+    
+    return YES;
+}
+
+- (BOOL)configureBufferSizeForSocket:(int)socket {
+    int buf_value = 65536;
+    socklen_t buf_len = sizeof(buf_value);
+    
+    if (setsockopt(socket, SOL_SOCKET, SO_RCVBUF, &buf_value, buf_len) == -1) {
+        NSLog(@"Failed to setup buffer size for input: %@", [NSString stringWithUTF8String:strerror(errno)]);
+        return NO;
+    }
+    
+    if (setsockopt(socket, SOL_SOCKET, SO_SNDBUF, &buf_value, buf_len) == -1) {
+        NSLog(@"Failed to setup buffer size for output: %@", [NSString stringWithUTF8String:strerror(errno)]);
+        return NO;
+    }
+    
+    return YES;
+}
+
+- (void)readPacketFlowPackets {
+    [self.packetFlow readPacketsWithCompletionHandler:^(NSArray<NSData *> * _Nonnull packets, NSArray<NSNumber *> * _Nonnull protocols) {
+        [self writeVPNPackets:packets protocols:protocols];
+        [self readPacketFlowPackets];
+    }];
+}
+
+- (void)writeVPNPackets:(NSArray<NSData *> *)packets protocols:(NSArray<NSNumber *> *)protocols {
+    [packets enumerateObjectsUsingBlock:^(NSData *data, NSUInteger idx, BOOL *stop) {
+        if (!_packetFlowSocket) {
+            *stop = YES;
+            return;
+        }
+        
+        // Prepare data for sending
+        NSData *packet = [self prepareVPNPacket:data protocol:protocols[idx]];
+        
+        // Send data to the VPN server
+        CFSocketSendData(_packetFlowSocket, NULL, (CFDataRef)packet, 0.05);
+    }];
+}
+
+- (NSData *)prepareVPNPacket:(NSData *)packet protocol:(NSNumber *)protocol {
+    NSMutableData *data = [NSMutableData new];
+    
+#if TARGET_OS_IPHONE
+    // Prepend data with network protocol. It should be done because OpenVPN on iOS uses uint32_t prefixes containing network protocol.
+    uint32_t prefix = CFSwapInt32HostToBig((uint32_t)[protocol unsignedIntegerValue]);
+    [data appendBytes:&prefix length:sizeof(prefix)];
+#endif
+    
+    [data appendData:packet];
+    
+    return [data copy];
+}
+
+- (void)writeDataToPacketFlow:(NSData *)packet {
+#if TARGET_OS_IPHONE
+    // Get network protocol from prefix
+    NSUInteger prefixSize = sizeof(uint32_t);
+    
+    if (packet.length < prefixSize) {
+        NSLog(@"Incorrect OpenVPN packet size");
+        return;
+    }
+    
+    uint32_t protocol = PF_UNSPEC;
+    [packet getBytes:&protocol length:prefixSize];
+    protocol = CFSwapInt32BigToHost(protocol);
+    
+    NSRange range = NSMakeRange(prefixSize, packet.length - prefixSize);
+    NSData *data = [packet subdataWithRange:range];
+#else
+    // Get network protocol from header
+    uint8_t header = 0;
+    [packet getBytes:&header length:1];
+    
+    uint32_t version = openvpn::IPHeader::version(header);
+    uint8_t protocol = [self protocolFamilyForVersion:version];
+    
+    NSData *data = packet;
+#endif
+    
+    // Send the packet to the TUN interface
+    if (![self.packetFlow writePackets:@[data] withProtocols:@[@(protocol)]]) {
+        NSLog(@"Failed to send OpenVPN packet to the TUN interface");
+    }
+}
+
+- (uint8_t)protocolFamilyForVersion:(uint32_t)version {
+    switch (version) {
+        case 4: return PF_INET;
+        case 6: return PF_INET6;
+        default: return PF_UNSPEC;
+    }
+}
+
+- (void)dealloc {
+    if (_packetFlowSocket) {
+        CFSocketInvalidate(_packetFlowSocket);
+        CFRelease(_packetFlowSocket);
+    }
+    
+    if (_openVPNClientSocket) {
+        CFSocketInvalidate(_openVPNClientSocket);
+        CFRelease(_openVPNClientSocket);
+    }
+}
+
+@end