diff --git a/OpenVPN Adapter.xcodeproj/project.pbxproj b/OpenVPN Adapter.xcodeproj/project.pbxproj
index dccbcb0..88439b3 100644
--- a/OpenVPN Adapter.xcodeproj/project.pbxproj	
+++ b/OpenVPN Adapter.xcodeproj/project.pbxproj	
@@ -124,6 +124,8 @@
 		C9C1E4111FA47117006ECA7D /* remote_vpn_server.ovpn in Resources */ = {isa = PBXBuildFile; fileRef = C9C1E40F1FA47117006ECA7D /* remote_vpn_server.ovpn */; };
 		C9C1E4141FA475B7006ECA7D /* CustomFlow.swift in Sources */ = {isa = PBXBuildFile; fileRef = C9C1E4131FA475B7006ECA7D /* CustomFlow.swift */; };
 		C9C1E4151FA475B7006ECA7D /* CustomFlow.swift in Sources */ = {isa = PBXBuildFile; fileRef = C9C1E4131FA475B7006ECA7D /* CustomFlow.swift */; };
+		C9C2B2B7200CB42F00CA0FF3 /* OpenVPNAdapterPacketFlow.h in Headers */ = {isa = PBXBuildFile; fileRef = C9C2B2B6200CB42F00CA0FF3 /* OpenVPNAdapterPacketFlow.h */; settings = {ATTRIBUTES = (Public, ); }; };
+		C9C2B2B8200CB42F00CA0FF3 /* OpenVPNAdapterPacketFlow.h in Headers */ = {isa = PBXBuildFile; fileRef = C9C2B2B6200CB42F00CA0FF3 /* OpenVPNAdapterPacketFlow.h */; settings = {ATTRIBUTES = (Public, ); }; };
 		C9CA4DD31F602F7B00C4F184 /* OpenVPNCertificate.h in Headers */ = {isa = PBXBuildFile; fileRef = C9CA4DD11F602F7B00C4F184 /* OpenVPNCertificate.h */; settings = {ATTRIBUTES = (Public, ); }; };
 		C9CA4DD41F602F7B00C4F184 /* OpenVPNCertificate.h in Headers */ = {isa = PBXBuildFile; fileRef = C9CA4DD11F602F7B00C4F184 /* OpenVPNCertificate.h */; settings = {ATTRIBUTES = (Public, ); }; };
 		C9CA4DD51F602F7B00C4F184 /* OpenVPNCertificate.m in Sources */ = {isa = PBXBuildFile; fileRef = C9CA4DD21F602F7B00C4F184 /* OpenVPNCertificate.m */; };
@@ -241,6 +243,7 @@
 		C9BCE25C1EB3C201009D6AC1 /* OpenVPNSessionToken+Internal.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = "OpenVPNSessionToken+Internal.h"; sourceTree = "<group>"; };
 		C9C1E40F1FA47117006ECA7D /* remote_vpn_server.ovpn */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = text; path = remote_vpn_server.ovpn; sourceTree = "<group>"; };
 		C9C1E4131FA475B7006ECA7D /* CustomFlow.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = CustomFlow.swift; sourceTree = "<group>"; };
+		C9C2B2B6200CB42F00CA0FF3 /* OpenVPNAdapterPacketFlow.h */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.h; path = OpenVPNAdapterPacketFlow.h; sourceTree = "<group>"; };
 		C9CA4DD11F602F7B00C4F184 /* OpenVPNCertificate.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = OpenVPNCertificate.h; sourceTree = "<group>"; };
 		C9CA4DD21F602F7B00C4F184 /* OpenVPNCertificate.m */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.objc; path = OpenVPNCertificate.m; sourceTree = "<group>"; };
 		C9CA4DE01F603A5300C4F184 /* OpenVPNCertificateTests.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = OpenVPNCertificateTests.swift; sourceTree = "<group>"; };
@@ -436,6 +439,7 @@
 				ABD6EF161F8F9C38007D3D90 /* OpenVPNAdapter.mm */,
 				ABD6EF071F8F8CCD007D3D90 /* OpenVPNNetworkSettingsBuilder.h */,
 				ABD6EF081F8F8CCD007D3D90 /* OpenVPNNetworkSettingsBuilder.m */,
+				C9C2B2B6200CB42F00CA0FF3 /* OpenVPNAdapterPacketFlow.h */,
 				ABD6EF0E1F8F93AB007D3D90 /* OpenVPNPacketFlowBridge.h */,
 				ABD6EF0F1F8F93AB007D3D90 /* OpenVPNPacketFlowBridge.mm */,
 			);
@@ -604,6 +608,7 @@
 				C93779D51EAE32670030A362 /* OpenVPNCredentials.h in Headers */,
 				C9657A641EB0D6C200EFF210 /* OpenVPNCompressionMode.h in Headers */,
 				C9FD921A1E9A667600374FC4 /* ovpncli.hpp in Headers */,
+				C9C2B2B7200CB42F00CA0FF3 /* OpenVPNAdapterPacketFlow.h in Headers */,
 				C93779DB1EAE32880030A362 /* OpenVPNCredentials+Internal.h in Headers */,
 				C9657A6A1EB0D75700EFF210 /* OpenVPNTLSCertProfile.h in Headers */,
 				C9657A461EB0CB5900EFF210 /* OpenVPNServerEntry+Internal.h in Headers */,
@@ -648,6 +653,7 @@
 				C93779D61EAE32670030A362 /* OpenVPNCredentials.h in Headers */,
 				C9657A651EB0D6C200EFF210 /* OpenVPNCompressionMode.h in Headers */,
 				C9D2ABEA1EA20F99007EDF9D /* ovpncli.hpp in Headers */,
+				C9C2B2B8200CB42F00CA0FF3 /* OpenVPNAdapterPacketFlow.h in Headers */,
 				C93779DC1EAE32880030A362 /* OpenVPNCredentials+Internal.h in Headers */,
 				C9657A6B1EB0D75700EFF210 /* OpenVPNTLSCertProfile.h in Headers */,
 				C9657A471EB0CB5900EFF210 /* OpenVPNServerEntry+Internal.h in Headers */,
diff --git a/OpenVPN Adapter/OpenVPNAdapterPacketFlow.h b/OpenVPN Adapter/OpenVPNAdapterPacketFlow.h
new file mode 100644
index 0000000..958a5ba
--- /dev/null
+++ b/OpenVPN Adapter/OpenVPNAdapterPacketFlow.h	
@@ -0,0 +1,35 @@
+//
+//  OpenVPNAdapterPacketFlow.h
+//  OpenVPN Adapter
+//
+//  Created by Sergey Abramchuk on 15.01.2018.
+//
+
+#import <Foundation/Foundation.h>
+
+@protocol OpenVPNAdapterPacketFlow <NSObject>
+
+/**
+ Read IP packets from the TUN interface.
+ 
+ @param completionHandler A block that is executed when some packets are read from the TUN interface. The packets that were
+ read are passed to this block in the packets array. The protocol numbers of the packets that were read are passed to this
+ block in the protocols array. Each packet has a protocol number in the corresponding index in the protocols array. The
+ protocol numbers are given in host byte order. Valid protocol numbers include PF_INET and PF_INET6. See /usr/include/sys/socket.h.
+ */
+- (void)readPacketsWithCompletionHandler:(void (^)(NSArray<NSData *> *packets, NSArray<NSNumber *> *protocols))completionHandler;
+
+/**
+ Write IP packets to the TUN interface
+ 
+ @param packets An array of NSData objects containing the IP packets to the written.
+ @param protocols An array of NSNumber objects containing the protocol numbers (e.g. PF_INET or PF_INET6) of the IP packets
+ in packets in host byte order.
+ 
+ @discussion The number of NSData objects in packets must be exactly equal to the number of NSNumber objects in protocols.
+ 
+ @return YES on success, otherwise NO.
+ */
+- (BOOL)writePackets:(NSArray<NSData *> *)packets withProtocols:(NSArray<NSNumber *> *)protocols;
+
+@end
diff --git a/OpenVPN Adapter/Umbrella-Header.h b/OpenVPN Adapter/Umbrella-Header.h
index 95b98cf..f195964 100644
--- a/OpenVPN Adapter/Umbrella-Header.h	
+++ b/OpenVPN Adapter/Umbrella-Header.h	
@@ -32,6 +32,7 @@ FOUNDATION_EXPORT const unsigned char OpenVPNAdapterVersionString[];
 #import <OpenVPNAdapter/OpenVPNTransportStats.h>
 #import <OpenVPNAdapter/OpenVPNInterfaceStats.h>
 #import <OpenVPNAdapter/OpenVPNAdapter.h>
+#import <OpenVPNAdapter/OpenVPNAdapterPacketFlow.h>
 #import <OpenVPNAdapter/OpenVPNKeyType.h>
 #import <OpenVPNAdapter/OpenVPNCertificate.h>
 #import <OpenVPNAdapter/OpenVPNPrivateKey.h>