Add FBPortForwarding source code

Summary:
See FBPortForwarding/README.md for an explanation of what this is.
It's required for the upcoming support for physical iOS devices.

To simplify development of the JS app, We're going to bundle the pre-built PortForwardingMacApp
inside the repo, and inside the electron app (static/PortForwardingMacApp.app).
Adding this source so users can build it from source if they choose to.

Reviewed By: danielbuechele

Differential Revision: D13276022

fbshipit-source-id: 99b18e0412cf443bb4a67eb4846cc780e0014de1

iOS/FlipperKit/FKPortForwarding/FKPortForwardingServer.m

@@ -0,0 +1,185 @@
+// Copyright 2004-present Facebook. All Rights Reserved.
+
+#import "FKPortForwardingServer.h"
+
+#import <UIKit/UIKit.h>
+
+#import <CocoaAsyncSocket/GCDAsyncSocket.h>
+#import <peertalk/PTChannel.h>
+
+#import "FKPortForwardingCommon.h"
+
+@interface FKPortForwardingServer () <PTChannelDelegate, GCDAsyncSocketDelegate>
+{
+  __weak PTChannel *_serverChannel;
+  __weak PTChannel *_peerChannel;
+
+  GCDAsyncSocket *_serverSocket;
+  NSMutableDictionary *_clientSockets;
+  UInt32 _lastClientSocketTag;
+  dispatch_queue_t _socketQueue;
+  PTProtocol *_protocol;
+}
+
+@end
+
+@implementation FKPortForwardingServer
+
+- (instancetype)init
+{
+  if (self = [super init]) {
+    _socketQueue = dispatch_queue_create("FKPortForwardingServer", DISPATCH_QUEUE_SERIAL);
+    _lastClientSocketTag = 0;
+    _clientSockets = [NSMutableDictionary dictionary];
+    _protocol = [[PTProtocol alloc] initWithDispatchQueue:_socketQueue];
+  }
+  return self;
+}
+
+- (void)dealloc
+{
+  [self close];
+  [[NSNotificationCenter defaultCenter] removeObserver:self];
+}
+
+- (void)forwardConnectionsFromPort:(NSUInteger)port
+{
+  [self _forwardConnectionsFromPort:port reportError:YES];
+  [[NSNotificationCenter defaultCenter] addObserverForName:UIApplicationDidBecomeActiveNotification object:nil queue:nil usingBlock:^(NSNotification *note) {
+    [self _forwardConnectionsFromPort:port reportError:NO];
+  }];
+}
+
+- (void)_forwardConnectionsFromPort:(NSUInteger)port reportError:(BOOL)shouldReportError
+{
+  GCDAsyncSocket *serverSocket = [[GCDAsyncSocket alloc] initWithDelegate:self delegateQueue:_socketQueue];
+  NSError *listenError;
+  if ([serverSocket acceptOnPort:port error:&listenError]) {
+    _serverSocket = serverSocket;
+  } else {
+    if (shouldReportError) {
+      FBPFLog(@"Failed to listen: %@", listenError);
+    }
+  }
+}
+
+- (void)listenForMultiplexingChannelOnPort:(NSUInteger)port
+{
+  [self _listenForMultiplexingChannelOnPort:port reportError:YES];
+  [[NSNotificationCenter defaultCenter] addObserverForName:UIApplicationDidBecomeActiveNotification object:nil queue:nil usingBlock:^(NSNotification *note) {
+    [self _listenForMultiplexingChannelOnPort:port reportError:NO];
+  }];
+}
+
+- (void)_listenForMultiplexingChannelOnPort:(NSUInteger)port reportError:(BOOL)shouldReportError
+{
+  PTChannel *channel = [[PTChannel alloc] initWithProtocol:_protocol delegate:self];
+  [channel listenOnPort:port IPv4Address:INADDR_LOOPBACK callback:^(NSError *error) {
+    if (error) {
+      if (shouldReportError) {
+        FBPFLog(@"Failed to listen on 127.0.0.1:%lu: %@", (unsigned long)port, error);
+      }
+    } else {
+      FBPFTrace(@"Listening on 127.0.0.1:%lu", (unsigned long)port);
+      self->_serverChannel = channel;
+    }
+  }];
+}
+
+- (void)close
+{
+  if (_serverChannel) {
+    [_serverChannel close];
+    _serverChannel = nil;
+  }
+  [_serverSocket disconnect];
+}
+
+#pragma mark - PTChannelDelegate
+
+- (void)ioFrameChannel:(PTChannel *)channel didAcceptConnection:(PTChannel *)otherChannel fromAddress:(PTAddress *)address {
+  // Cancel any other connection. We are FIFO, so the last connection
+  // established will cancel any previous connection and "take its place".
+  if (_peerChannel) {
+    [_peerChannel cancel];
+  }
+
+  // Weak pointer to current connection. Connection objects live by themselves
+  // (owned by its parent dispatch queue) until they are closed.
+  _peerChannel = otherChannel;
+  _peerChannel.userInfo = address;
+  FBPFTrace(@"Connected to %@", address);
+}
+
+- (void)ioFrameChannel:(PTChannel *)channel didReceiveFrameOfType:(uint32_t)type tag:(uint32_t)tag payload:(PTData *)payload {
+  //NSLog(@"didReceiveFrameOfType: %u, %u, %@", type, tag, payload);
+  if (type == FKPortForwardingFrameTypeWriteToPipe) {
+    GCDAsyncSocket *sock = _clientSockets[@(tag)];
+    [sock writeData:[NSData dataWithBytes:payload.data length:payload.length] withTimeout:-1 tag:0];
+    FBPFTrace(@"channel -> socket (%d), %zu bytes", tag, payload.length);
+  }
+
+  if (type == FKPortForwardingFrameTypeClosePipe) {
+    GCDAsyncSocket *sock = _clientSockets[@(tag)];
+    [sock disconnectAfterWriting];
+  }
+}
+
+- (void)ioFrameChannel:(PTChannel *)channel didEndWithError:(NSError *)error {
+  for (GCDAsyncSocket *sock in [_clientSockets objectEnumerator]) {
+    [sock setDelegate:nil];
+    [sock disconnect];
+  }
+  [_clientSockets removeAllObjects];
+  FBPFTrace(@"Disconnected from %@, error = %@", channel.userInfo, error);
+}
+
+
+#pragma mark - GCDAsyncSocketDelegate
+
+- (void)socket:(GCDAsyncSocket *)sock didAcceptNewSocket:(GCDAsyncSocket *)newSocket
+{
+  dispatch_block_t block = ^() {
+    if (!self->_peerChannel) {
+      [newSocket setDelegate:nil];
+      [newSocket disconnect];
+    }
+
+    UInt32 tag = ++self->_lastClientSocketTag;
+    newSocket.userData = @(tag);
+    newSocket.delegate = self;
+    self->_clientSockets[@(tag)] = newSocket;
+    [self->_peerChannel sendFrameOfType:FKPortForwardingFrameTypeOpenPipe tag:self->_lastClientSocketTag withPayload:nil callback:^(NSError *error) {
+      FBPFTrace(@"open socket (%d), error = %@", (unsigned int)tag, error);
+      [newSocket readDataWithTimeout:-1 tag:0];
+    }];
+  };
+
+  if (_peerChannel) {
+    block();
+  } else {
+    dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(1 * NSEC_PER_SEC)), _socketQueue, block);
+  }
+}
+
+- (void)socket:(GCDAsyncSocket *)sock didReadData:(NSData *)data withTag:(long)_
+{
+  UInt32 tag = [[sock userData] unsignedIntValue];
+  FBPFTrace(@"Incoming data on socket (%d) - %lu bytes", (unsigned int)tag, (unsigned long)data.length);
+  [_peerChannel sendFrameOfType:FKPortForwardingFrameTypeWriteToPipe tag:tag withPayload:NSDataToGCDData(data) callback:^(NSError *error) {
+    FBPFTrace(@"socket (%d) -> channel %lu bytes, error = %@", (unsigned int)tag, (unsigned long)data.length, error);
+    [sock readDataWithTimeout:-1 tag:_];
+  }];
+}
+
+- (void)socketDidDisconnect:(GCDAsyncSocket *)sock withError:(NSError *)err
+{
+  UInt32 tag = [sock.userData unsignedIntValue];
+  [_clientSockets removeObjectForKey:@(tag)];
+  [_peerChannel sendFrameOfType:FKPortForwardingFrameTypeClosePipe tag:tag withPayload:nil callback:^(NSError *error) {
+    FBPFTrace(@"socket (%d) disconnected, err = %@, peer error = %@", (unsigned int)tag, err, error);
+  }];
+}
+
+
+@end