diff --git a/webrtc/base/virtualsocketserver.cc b/webrtc/base/virtualsocketserver.cc
new file mode 100644
index 0000000..f8e8dde
--- /dev/null
+++ b/webrtc/base/virtualsocketserver.cc
@@ -0,0 +1,1101 @@
+/*
+ *  Copyright 2004 The WebRTC Project Authors. All rights reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#include "webrtc/base/virtualsocketserver.h"
+
+#include <errno.h>
+#include <math.h>
+
+#include <algorithm>
+#include <map>
+#include <vector>
+
+#include "webrtc/base/common.h"
+#include "webrtc/base/logging.h"
+#include "webrtc/base/physicalsocketserver.h"
+#include "webrtc/base/socketaddresspair.h"
+#include "webrtc/base/thread.h"
+#include "webrtc/base/timeutils.h"
+
+namespace rtc {
+#if defined(WEBRTC_WIN)
+const in_addr kInitialNextIPv4 = { {0x01, 0, 0, 0} };
+#else
+// This value is entirely arbitrary, hence the lack of concern about endianness.
+const in_addr kInitialNextIPv4 = { 0x01000000 };
+#endif
+// Starts at ::2 so as to not cause confusion with ::1.
+const in6_addr kInitialNextIPv6 = { { {
+      0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 2
+    } } };
+
+const uint16 kFirstEphemeralPort = 49152;
+const uint16 kLastEphemeralPort = 65535;
+const uint16 kEphemeralPortCount = kLastEphemeralPort - kFirstEphemeralPort + 1;
+const uint32 kDefaultNetworkCapacity = 64 * 1024;
+const uint32 kDefaultTcpBufferSize = 32 * 1024;
+
+const uint32 UDP_HEADER_SIZE = 28;  // IP + UDP headers
+const uint32 TCP_HEADER_SIZE = 40;  // IP + TCP headers
+const uint32 TCP_MSS = 1400;  // Maximum segment size
+
+// Note: The current algorithm doesn't work for sample sizes smaller than this.
+const int NUM_SAMPLES = 1000;
+
+enum {
+  MSG_ID_PACKET,
+  MSG_ID_CONNECT,
+  MSG_ID_DISCONNECT,
+};
+
+// Packets are passed between sockets as messages.  We copy the data just like
+// the kernel does.
+class Packet : public MessageData {
+ public:
+  Packet(const char* data, size_t size, const SocketAddress& from)
+        : size_(size), consumed_(0), from_(from) {
+    ASSERT(NULL != data);
+    data_ = new char[size_];
+    memcpy(data_, data, size_);
+  }
+
+  virtual ~Packet() {
+    delete[] data_;
+  }
+
+  const char* data() const { return data_ + consumed_; }
+  size_t size() const { return size_ - consumed_; }
+  const SocketAddress& from() const { return from_; }
+
+  // Remove the first size bytes from the data.
+  void Consume(size_t size) {
+    ASSERT(size + consumed_ < size_);
+    consumed_ += size;
+  }
+
+ private:
+  char* data_;
+  size_t size_, consumed_;
+  SocketAddress from_;
+};
+
+struct MessageAddress : public MessageData {
+  explicit MessageAddress(const SocketAddress& a) : addr(a) { }
+  SocketAddress addr;
+};
+
+// Implements the socket interface using the virtual network.  Packets are
+// passed as messages using the message queue of the socket server.
+class VirtualSocket : public AsyncSocket, public MessageHandler {
+ public:
+  VirtualSocket(VirtualSocketServer* server, int family, int type, bool async)
+      : server_(server), family_(family), type_(type), async_(async),
+        state_(CS_CLOSED), error_(0), listen_queue_(NULL),
+        write_enabled_(false),
+        network_size_(0), recv_buffer_size_(0), bound_(false), was_any_(false) {
+    ASSERT((type_ == SOCK_DGRAM) || (type_ == SOCK_STREAM));
+    ASSERT(async_ || (type_ != SOCK_STREAM));  // We only support async streams
+  }
+
+  virtual ~VirtualSocket() {
+    Close();
+
+    for (RecvBuffer::iterator it = recv_buffer_.begin();
+         it != recv_buffer_.end(); ++it) {
+      delete *it;
+    }
+  }
+
+  virtual SocketAddress GetLocalAddress() const {
+    return local_addr_;
+  }
+
+  virtual SocketAddress GetRemoteAddress() const {
+    return remote_addr_;
+  }
+
+  // Used by server sockets to set the local address without binding.
+  void SetLocalAddress(const SocketAddress& addr) {
+    local_addr_ = addr;
+  }
+
+  virtual int Bind(const SocketAddress& addr) {
+    if (!local_addr_.IsNil()) {
+      error_ = EINVAL;
+      return -1;
+    }
+    local_addr_ = addr;
+    int result = server_->Bind(this, &local_addr_);
+    if (result != 0) {
+      local_addr_.Clear();
+      error_ = EADDRINUSE;
+    } else {
+      bound_ = true;
+      was_any_ = addr.IsAnyIP();
+    }
+    return result;
+  }
+
+  virtual int Connect(const SocketAddress& addr) {
+    return InitiateConnect(addr, true);
+  }
+
+  virtual int Close() {
+    if (!local_addr_.IsNil() && bound_) {
+      // Remove from the binding table.
+      server_->Unbind(local_addr_, this);
+      bound_ = false;
+    }
+
+    if (SOCK_STREAM == type_) {
+      // Cancel pending sockets
+      if (listen_queue_) {
+        while (!listen_queue_->empty()) {
+          SocketAddress addr = listen_queue_->front();
+
+          // Disconnect listening socket.
+          server_->Disconnect(server_->LookupBinding(addr));
+          listen_queue_->pop_front();
+        }
+        delete listen_queue_;
+        listen_queue_ = NULL;
+      }
+      // Disconnect stream sockets
+      if (CS_CONNECTED == state_) {
+        // Disconnect remote socket, check if it is a child of a server socket.
+        VirtualSocket* socket =
+            server_->LookupConnection(local_addr_, remote_addr_);
+        if (!socket) {
+          // Not a server socket child, then see if it is bound.
+          // TODO: If this is indeed a server socket that has no
+          // children this will cause the server socket to be
+          // closed. This might lead to unexpected results, how to fix this?
+          socket = server_->LookupBinding(remote_addr_);
+        }
+        server_->Disconnect(socket);
+
+        // Remove mapping for both directions.
+        server_->RemoveConnection(remote_addr_, local_addr_);
+        server_->RemoveConnection(local_addr_, remote_addr_);
+      }
+      // Cancel potential connects
+      MessageList msgs;
+      if (server_->msg_queue_) {
+        server_->msg_queue_->Clear(this, MSG_ID_CONNECT, &msgs);
+      }
+      for (MessageList::iterator it = msgs.begin(); it != msgs.end(); ++it) {
+        ASSERT(NULL != it->pdata);
+        MessageAddress* data = static_cast<MessageAddress*>(it->pdata);
+
+        // Lookup remote side.
+        VirtualSocket* socket = server_->LookupConnection(local_addr_,
+                                                          data->addr);
+        if (socket) {
+          // Server socket, remote side is a socket retreived by
+          // accept. Accepted sockets are not bound so we will not
+          // find it by looking in the bindings table.
+          server_->Disconnect(socket);
+          server_->RemoveConnection(local_addr_, data->addr);
+        } else {
+          server_->Disconnect(server_->LookupBinding(data->addr));
+        }
+        delete data;
+      }
+      // Clear incoming packets and disconnect messages
+      if (server_->msg_queue_) {
+        server_->msg_queue_->Clear(this);
+      }
+    }
+
+    state_ = CS_CLOSED;
+    local_addr_.Clear();
+    remote_addr_.Clear();
+    return 0;
+  }
+
+  virtual int Send(const void *pv, size_t cb) {
+    if (CS_CONNECTED != state_) {
+      error_ = ENOTCONN;
+      return -1;
+    }
+    if (SOCK_DGRAM == type_) {
+      return SendUdp(pv, cb, remote_addr_);
+    } else {
+      return SendTcp(pv, cb);
+    }
+  }
+
+  virtual int SendTo(const void *pv, size_t cb, const SocketAddress& addr) {
+    if (SOCK_DGRAM == type_) {
+      return SendUdp(pv, cb, addr);
+    } else {
+      if (CS_CONNECTED != state_) {
+        error_ = ENOTCONN;
+        return -1;
+      }
+      return SendTcp(pv, cb);
+    }
+  }
+
+  virtual int Recv(void *pv, size_t cb) {
+    SocketAddress addr;
+    return RecvFrom(pv, cb, &addr);
+  }
+
+  virtual int RecvFrom(void *pv, size_t cb, SocketAddress *paddr) {
+    // If we don't have a packet, then either error or wait for one to arrive.
+    if (recv_buffer_.empty()) {
+      if (async_) {
+        error_ = EAGAIN;
+        return -1;
+      }
+      while (recv_buffer_.empty()) {
+        Message msg;
+        server_->msg_queue_->Get(&msg);
+        server_->msg_queue_->Dispatch(&msg);
+      }
+    }
+
+    // Return the packet at the front of the queue.
+    Packet* packet = recv_buffer_.front();
+    size_t data_read = _min(cb, packet->size());
+    memcpy(pv, packet->data(), data_read);
+    *paddr = packet->from();
+
+    if (data_read < packet->size()) {
+      packet->Consume(data_read);
+    } else {
+      recv_buffer_.pop_front();
+      delete packet;
+    }
+
+    if (SOCK_STREAM == type_) {
+      bool was_full = (recv_buffer_size_ == server_->recv_buffer_capacity_);
+      recv_buffer_size_ -= data_read;
+      if (was_full) {
+        VirtualSocket* sender = server_->LookupBinding(remote_addr_);
+        ASSERT(NULL != sender);
+        server_->SendTcp(sender);
+      }
+    }
+
+    return static_cast<int>(data_read);
+  }
+
+  virtual int Listen(int backlog) {
+    ASSERT(SOCK_STREAM == type_);
+    ASSERT(CS_CLOSED == state_);
+    if (local_addr_.IsNil()) {
+      error_ = EINVAL;
+      return -1;
+    }
+    ASSERT(NULL == listen_queue_);
+    listen_queue_ = new ListenQueue;
+    state_ = CS_CONNECTING;
+    return 0;
+  }
+
+  virtual VirtualSocket* Accept(SocketAddress *paddr) {
+    if (NULL == listen_queue_) {
+      error_ = EINVAL;
+      return NULL;
+    }
+    while (!listen_queue_->empty()) {
+      VirtualSocket* socket = new VirtualSocket(server_, AF_INET, type_,
+                                                async_);
+
+      // Set the new local address to the same as this server socket.
+      socket->SetLocalAddress(local_addr_);
+      // Sockets made from a socket that 'was Any' need to inherit that.
+      socket->set_was_any(was_any_);
+      SocketAddress remote_addr(listen_queue_->front());
+      int result = socket->InitiateConnect(remote_addr, false);
+      listen_queue_->pop_front();
+      if (result != 0) {
+        delete socket;
+        continue;
+      }
+      socket->CompleteConnect(remote_addr, false);
+      if (paddr) {
+        *paddr = remote_addr;
+      }
+      return socket;
+    }
+    error_ = EWOULDBLOCK;
+    return NULL;
+  }
+
+  virtual int GetError() const {
+    return error_;
+  }
+
+  virtual void SetError(int error) {
+    error_ = error;
+  }
+
+  virtual ConnState GetState() const {
+    return state_;
+  }
+
+  virtual int GetOption(Option opt, int* value) {
+    OptionsMap::const_iterator it = options_map_.find(opt);
+    if (it == options_map_.end()) {
+      return -1;
+    }
+    *value = it->second;
+    return 0;  // 0 is success to emulate getsockopt()
+  }
+
+  virtual int SetOption(Option opt, int value) {
+    options_map_[opt] = value;
+    return 0;  // 0 is success to emulate setsockopt()
+  }
+
+  virtual int EstimateMTU(uint16* mtu) {
+    if (CS_CONNECTED != state_)
+      return ENOTCONN;
+    else
+      return 65536;
+  }
+
+  void OnMessage(Message *pmsg) {
+    if (pmsg->message_id == MSG_ID_PACKET) {
+      //ASSERT(!local_addr_.IsAny());
+      ASSERT(NULL != pmsg->pdata);
+      Packet* packet = static_cast<Packet*>(pmsg->pdata);
+
+      recv_buffer_.push_back(packet);
+
+      if (async_) {
+        SignalReadEvent(this);
+      }
+    } else if (pmsg->message_id == MSG_ID_CONNECT) {
+      ASSERT(NULL != pmsg->pdata);
+      MessageAddress* data = static_cast<MessageAddress*>(pmsg->pdata);
+      if (listen_queue_ != NULL) {
+        listen_queue_->push_back(data->addr);
+        if (async_) {
+          SignalReadEvent(this);
+        }
+      } else if ((SOCK_STREAM == type_) && (CS_CONNECTING == state_)) {
+        CompleteConnect(data->addr, true);
+      } else {
+        LOG(LS_VERBOSE) << "Socket at " << local_addr_ << " is not listening";
+        server_->Disconnect(server_->LookupBinding(data->addr));
+      }
+      delete data;
+    } else if (pmsg->message_id == MSG_ID_DISCONNECT) {
+      ASSERT(SOCK_STREAM == type_);
+      if (CS_CLOSED != state_) {
+        int error = (CS_CONNECTING == state_) ? ECONNREFUSED : 0;
+        state_ = CS_CLOSED;
+        remote_addr_.Clear();
+        if (async_) {
+          SignalCloseEvent(this, error);
+        }
+      }
+    } else {
+      ASSERT(false);
+    }
+  }
+
+  bool was_any() { return was_any_; }
+  void set_was_any(bool was_any) { was_any_ = was_any; }
+
+ private:
+  struct NetworkEntry {
+    size_t size;
+    uint32 done_time;
+  };
+
+  typedef std::deque<SocketAddress> ListenQueue;
+  typedef std::deque<NetworkEntry> NetworkQueue;
+  typedef std::vector<char> SendBuffer;
+  typedef std::list<Packet*> RecvBuffer;
+  typedef std::map<Option, int> OptionsMap;
+
+  int InitiateConnect(const SocketAddress& addr, bool use_delay) {
+    if (!remote_addr_.IsNil()) {
+      error_ = (CS_CONNECTED == state_) ? EISCONN : EINPROGRESS;
+      return -1;
+    }
+    if (local_addr_.IsNil()) {
+      // If there's no local address set, grab a random one in the correct AF.
+      int result = 0;
+      if (addr.ipaddr().family() == AF_INET) {
+        result = Bind(SocketAddress("0.0.0.0", 0));
+      } else if (addr.ipaddr().family() == AF_INET6) {
+        result = Bind(SocketAddress("::", 0));
+      }
+      if (result != 0) {
+        return result;
+      }
+    }
+    if (type_ == SOCK_DGRAM) {
+      remote_addr_ = addr;
+      state_ = CS_CONNECTED;
+    } else {
+      int result = server_->Connect(this, addr, use_delay);
+      if (result != 0) {
+        error_ = EHOSTUNREACH;
+        return -1;
+      }
+      state_ = CS_CONNECTING;
+    }
+    return 0;
+  }
+
+  void CompleteConnect(const SocketAddress& addr, bool notify) {
+    ASSERT(CS_CONNECTING == state_);
+    remote_addr_ = addr;
+    state_ = CS_CONNECTED;
+    server_->AddConnection(remote_addr_, local_addr_, this);
+    if (async_ && notify) {
+      SignalConnectEvent(this);
+    }
+  }
+
+  int SendUdp(const void* pv, size_t cb, const SocketAddress& addr) {
+    // If we have not been assigned a local port, then get one.
+    if (local_addr_.IsNil()) {
+      local_addr_ = EmptySocketAddressWithFamily(addr.ipaddr().family());
+      int result = server_->Bind(this, &local_addr_);
+      if (result != 0) {
+        local_addr_.Clear();
+        error_ = EADDRINUSE;
+        return result;
+      }
+    }
+
+    // Send the data in a message to the appropriate socket.
+    return server_->SendUdp(this, static_cast<const char*>(pv), cb, addr);
+  }
+
+  int SendTcp(const void* pv, size_t cb) {
+    size_t capacity = server_->send_buffer_capacity_ - send_buffer_.size();
+    if (0 == capacity) {
+      write_enabled_ = true;
+      error_ = EWOULDBLOCK;
+      return -1;
+    }
+    size_t consumed = _min(cb, capacity);
+    const char* cpv = static_cast<const char*>(pv);
+    send_buffer_.insert(send_buffer_.end(), cpv, cpv + consumed);
+    server_->SendTcp(this);
+    return static_cast<int>(consumed);
+  }
+
+  VirtualSocketServer* server_;
+  int family_;
+  int type_;
+  bool async_;
+  ConnState state_;
+  int error_;
+  SocketAddress local_addr_;
+  SocketAddress remote_addr_;
+
+  // Pending sockets which can be Accepted
+  ListenQueue* listen_queue_;
+
+  // Data which tcp has buffered for sending
+  SendBuffer send_buffer_;
+  bool write_enabled_;
+
+  // Critical section to protect the recv_buffer and queue_
+  CriticalSection crit_;
+
+  // Network model that enforces bandwidth and capacity constraints
+  NetworkQueue network_;
+  size_t network_size_;
+
+  // Data which has been received from the network
+  RecvBuffer recv_buffer_;
+  // The amount of data which is in flight or in recv_buffer_
+  size_t recv_buffer_size_;
+
+  // Is this socket bound?
+  bool bound_;
+
+  // When we bind a socket to Any, VSS's Bind gives it another address. For
+  // dual-stack sockets, we want to distinguish between sockets that were
+  // explicitly given a particular address and sockets that had one picked
+  // for them by VSS.
+  bool was_any_;
+
+  // Store the options that are set
+  OptionsMap options_map_;
+
+  friend class VirtualSocketServer;
+};
+
+VirtualSocketServer::VirtualSocketServer(SocketServer* ss)
+    : server_(ss), server_owned_(false), msg_queue_(NULL), stop_on_idle_(false),
+      network_delay_(Time()), next_ipv4_(kInitialNextIPv4),
+      next_ipv6_(kInitialNextIPv6), next_port_(kFirstEphemeralPort),
+      bindings_(new AddressMap()), connections_(new ConnectionMap()),
+      bandwidth_(0), network_capacity_(kDefaultNetworkCapacity),
+      send_buffer_capacity_(kDefaultTcpBufferSize),
+      recv_buffer_capacity_(kDefaultTcpBufferSize),
+      delay_mean_(0), delay_stddev_(0), delay_samples_(NUM_SAMPLES),
+      delay_dist_(NULL), drop_prob_(0.0) {
+  if (!server_) {
+    server_ = new PhysicalSocketServer();
+    server_owned_ = true;
+  }
+  UpdateDelayDistribution();
+}
+
+VirtualSocketServer::~VirtualSocketServer() {
+  delete bindings_;
+  delete connections_;
+  delete delay_dist_;
+  if (server_owned_) {
+    delete server_;
+  }
+}
+
+IPAddress VirtualSocketServer::GetNextIP(int family) {
+  if (family == AF_INET) {
+    IPAddress next_ip(next_ipv4_);
+    next_ipv4_.s_addr =
+        HostToNetwork32(NetworkToHost32(next_ipv4_.s_addr) + 1);
+    return next_ip;
+  } else if (family == AF_INET6) {
+    IPAddress next_ip(next_ipv6_);
+    uint32* as_ints = reinterpret_cast<uint32*>(&next_ipv6_.s6_addr);
+    as_ints[3] += 1;
+    return next_ip;
+  }
+  return IPAddress();
+}
+
+uint16 VirtualSocketServer::GetNextPort() {
+  uint16 port = next_port_;
+  if (next_port_ < kLastEphemeralPort) {
+    ++next_port_;
+  } else {
+    next_port_ = kFirstEphemeralPort;
+  }
+  return port;
+}
+
+Socket* VirtualSocketServer::CreateSocket(int type) {
+  return CreateSocket(AF_INET, type);
+}
+
+Socket* VirtualSocketServer::CreateSocket(int family, int type) {
+  return CreateSocketInternal(family, type);
+}
+
+AsyncSocket* VirtualSocketServer::CreateAsyncSocket(int type) {
+  return CreateAsyncSocket(AF_INET, type);
+}
+
+AsyncSocket* VirtualSocketServer::CreateAsyncSocket(int family, int type) {
+  return CreateSocketInternal(family, type);
+}
+
+VirtualSocket* VirtualSocketServer::CreateSocketInternal(int family, int type) {
+  return new VirtualSocket(this, family, type, true);
+}
+
+void VirtualSocketServer::SetMessageQueue(MessageQueue* msg_queue) {
+  msg_queue_ = msg_queue;
+  if (msg_queue_) {
+    msg_queue_->SignalQueueDestroyed.connect(this,
+        &VirtualSocketServer::OnMessageQueueDestroyed);
+  }
+}
+
+bool VirtualSocketServer::Wait(int cmsWait, bool process_io) {
+  ASSERT(msg_queue_ == Thread::Current());
+  if (stop_on_idle_ && Thread::Current()->empty()) {
+    return false;
+  }
+  return socketserver()->Wait(cmsWait, process_io);
+}
+
+void VirtualSocketServer::WakeUp() {
+  socketserver()->WakeUp();
+}
+
+bool VirtualSocketServer::ProcessMessagesUntilIdle() {
+  ASSERT(msg_queue_ == Thread::Current());
+  stop_on_idle_ = true;
+  while (!msg_queue_->empty()) {
+    Message msg;
+    if (msg_queue_->Get(&msg, kForever)) {
+      msg_queue_->Dispatch(&msg);
+    }
+  }
+  stop_on_idle_ = false;
+  return !msg_queue_->IsQuitting();
+}
+
+int VirtualSocketServer::Bind(VirtualSocket* socket,
+                              const SocketAddress& addr) {
+  ASSERT(NULL != socket);
+  // Address must be completely specified at this point
+  ASSERT(!IPIsUnspec(addr.ipaddr()));
+  ASSERT(addr.port() != 0);
+
+  // Normalize the address (turns v6-mapped addresses into v4-addresses).
+  SocketAddress normalized(addr.ipaddr().Normalized(), addr.port());
+
+  AddressMap::value_type entry(normalized, socket);
+  return bindings_->insert(entry).second ? 0 : -1;
+}
+
+int VirtualSocketServer::Bind(VirtualSocket* socket, SocketAddress* addr) {
+  ASSERT(NULL != socket);
+
+  if (IPIsAny(addr->ipaddr())) {
+    addr->SetIP(GetNextIP(addr->ipaddr().family()));
+  } else if (!IPIsUnspec(addr->ipaddr())) {
+    addr->SetIP(addr->ipaddr().Normalized());
+  } else {
+    ASSERT(false);
+  }
+
+  if (addr->port() == 0) {
+    for (int i = 0; i < kEphemeralPortCount; ++i) {
+      addr->SetPort(GetNextPort());
+      if (bindings_->find(*addr) == bindings_->end()) {
+        break;
+      }
+    }
+  }
+
+  return Bind(socket, *addr);
+}
+
+VirtualSocket* VirtualSocketServer::LookupBinding(const SocketAddress& addr) {
+  SocketAddress normalized(addr.ipaddr().Normalized(),
+                           addr.port());
+  AddressMap::iterator it = bindings_->find(normalized);
+  return (bindings_->end() != it) ? it->second : NULL;
+}
+
+int VirtualSocketServer::Unbind(const SocketAddress& addr,
+                                VirtualSocket* socket) {
+  SocketAddress normalized(addr.ipaddr().Normalized(),
+                           addr.port());
+  ASSERT((*bindings_)[normalized] == socket);
+  bindings_->erase(bindings_->find(normalized));
+  return 0;
+}
+
+void VirtualSocketServer::AddConnection(const SocketAddress& local,
+                                        const SocketAddress& remote,
+                                        VirtualSocket* remote_socket) {
+  // Add this socket pair to our routing table. This will allow
+  // multiple clients to connect to the same server address.
+  SocketAddress local_normalized(local.ipaddr().Normalized(),
+                                 local.port());
+  SocketAddress remote_normalized(remote.ipaddr().Normalized(),
+                                  remote.port());
+  SocketAddressPair address_pair(local_normalized, remote_normalized);
+  connections_->insert(std::pair<SocketAddressPair,
+                       VirtualSocket*>(address_pair, remote_socket));
+}
+
+VirtualSocket* VirtualSocketServer::LookupConnection(
+    const SocketAddress& local,
+    const SocketAddress& remote) {
+  SocketAddress local_normalized(local.ipaddr().Normalized(),
+                                 local.port());
+  SocketAddress remote_normalized(remote.ipaddr().Normalized(),
+                                  remote.port());
+  SocketAddressPair address_pair(local_normalized, remote_normalized);
+  ConnectionMap::iterator it = connections_->find(address_pair);
+  return (connections_->end() != it) ? it->second : NULL;
+}
+
+void VirtualSocketServer::RemoveConnection(const SocketAddress& local,
+                                           const SocketAddress& remote) {
+  SocketAddress local_normalized(local.ipaddr().Normalized(),
+                                local.port());
+  SocketAddress remote_normalized(remote.ipaddr().Normalized(),
+                                 remote.port());
+  SocketAddressPair address_pair(local_normalized, remote_normalized);
+  connections_->erase(address_pair);
+}
+
+static double Random() {
+  return static_cast<double>(rand()) / RAND_MAX;
+}
+
+int VirtualSocketServer::Connect(VirtualSocket* socket,
+                                 const SocketAddress& remote_addr,
+                                 bool use_delay) {
+  uint32 delay = use_delay ? GetRandomTransitDelay() : 0;
+  VirtualSocket* remote = LookupBinding(remote_addr);
+  if (!CanInteractWith(socket, remote)) {
+    LOG(LS_INFO) << "Address family mismatch between "
+                 << socket->GetLocalAddress() << " and " << remote_addr;
+    return -1;
+  }
+  if (remote != NULL) {
+    SocketAddress addr = socket->GetLocalAddress();
+    msg_queue_->PostDelayed(delay, remote, MSG_ID_CONNECT,
+                            new MessageAddress(addr));
+  } else {
+    LOG(LS_INFO) << "No one listening at " << remote_addr;
+    msg_queue_->PostDelayed(delay, socket, MSG_ID_DISCONNECT);
+  }
+  return 0;
+}
+
+bool VirtualSocketServer::Disconnect(VirtualSocket* socket) {
+  if (socket) {
+    // Remove the mapping.
+    msg_queue_->Post(socket, MSG_ID_DISCONNECT);
+    return true;
+  }
+  return false;
+}
+
+int VirtualSocketServer::SendUdp(VirtualSocket* socket,
+                                 const char* data, size_t data_size,
+                                 const SocketAddress& remote_addr) {
+  // See if we want to drop this packet.
+  if (Random() < drop_prob_) {
+    LOG(LS_VERBOSE) << "Dropping packet: bad luck";
+    return static_cast<int>(data_size);
+  }
+
+  VirtualSocket* recipient = LookupBinding(remote_addr);
+  if (!recipient) {
+    // Make a fake recipient for address family checking.
+    scoped_ptr<VirtualSocket> dummy_socket(
+        CreateSocketInternal(AF_INET, SOCK_DGRAM));
+    dummy_socket->SetLocalAddress(remote_addr);
+    if (!CanInteractWith(socket, dummy_socket.get())) {
+      LOG(LS_VERBOSE) << "Incompatible address families: "
+                      << socket->GetLocalAddress() << " and " << remote_addr;
+      return -1;
+    }
+    LOG(LS_VERBOSE) << "No one listening at " << remote_addr;
+    return static_cast<int>(data_size);
+  }
+
+  if (!CanInteractWith(socket, recipient)) {
+    LOG(LS_VERBOSE) << "Incompatible address families: "
+                    << socket->GetLocalAddress() << " and " << remote_addr;
+    return -1;
+  }
+
+  CritScope cs(&socket->crit_);
+
+  uint32 cur_time = Time();
+  PurgeNetworkPackets(socket, cur_time);
+
+  // Determine whether we have enough bandwidth to accept this packet.  To do
+  // this, we need to update the send queue.  Once we know it's current size,
+  // we know whether we can fit this packet.
+  //
+  // NOTE: There are better algorithms for maintaining such a queue (such as
+  // "Derivative Random Drop"); however, this algorithm is a more accurate
+  // simulation of what a normal network would do.
+
+  size_t packet_size = data_size + UDP_HEADER_SIZE;
+  if (socket->network_size_ + packet_size > network_capacity_) {
+    LOG(LS_VERBOSE) << "Dropping packet: network capacity exceeded";
+    return static_cast<int>(data_size);
+  }
+
+  AddPacketToNetwork(socket, recipient, cur_time, data, data_size,
+                     UDP_HEADER_SIZE, false);
+
+  return static_cast<int>(data_size);
+}
+
+void VirtualSocketServer::SendTcp(VirtualSocket* socket) {
+  // TCP can't send more data than will fill up the receiver's buffer.
+  // We track the data that is in the buffer plus data in flight using the
+  // recipient's recv_buffer_size_.  Anything beyond that must be stored in the
+  // sender's buffer.  We will trigger the buffered data to be sent when data
+  // is read from the recv_buffer.
+
+  // Lookup the local/remote pair in the connections table.
+  VirtualSocket* recipient = LookupConnection(socket->local_addr_,
+                                              socket->remote_addr_);
+  if (!recipient) {
+    LOG(LS_VERBOSE) << "Sending data to no one.";
+    return;
+  }
+
+  CritScope cs(&socket->crit_);
+
+  uint32 cur_time = Time();
+  PurgeNetworkPackets(socket, cur_time);
+
+  while (true) {
+    size_t available = recv_buffer_capacity_ - recipient->recv_buffer_size_;
+    size_t max_data_size = _min<size_t>(available, TCP_MSS - TCP_HEADER_SIZE);
+    size_t data_size = _min(socket->send_buffer_.size(), max_data_size);
+    if (0 == data_size)
+      break;
+
+    AddPacketToNetwork(socket, recipient, cur_time, &socket->send_buffer_[0],
+                       data_size, TCP_HEADER_SIZE, true);
+    recipient->recv_buffer_size_ += data_size;
+
+    size_t new_buffer_size = socket->send_buffer_.size() - data_size;
+    // Avoid undefined access beyond the last element of the vector.
+    // This only happens when new_buffer_size is 0.
+    if (data_size < socket->send_buffer_.size()) {
+      // memmove is required for potentially overlapping source/destination.
+      memmove(&socket->send_buffer_[0], &socket->send_buffer_[data_size],
+              new_buffer_size);
+    }
+    socket->send_buffer_.resize(new_buffer_size);
+  }
+
+  if (socket->write_enabled_
+      && (socket->send_buffer_.size() < send_buffer_capacity_)) {
+    socket->write_enabled_ = false;
+    socket->SignalWriteEvent(socket);
+  }
+}
+
+void VirtualSocketServer::AddPacketToNetwork(VirtualSocket* sender,
+                                             VirtualSocket* recipient,
+                                             uint32 cur_time,
+                                             const char* data,
+                                             size_t data_size,
+                                             size_t header_size,
+                                             bool ordered) {
+  VirtualSocket::NetworkEntry entry;
+  entry.size = data_size + header_size;
+
+  sender->network_size_ += entry.size;
+  uint32 send_delay = SendDelay(static_cast<uint32>(sender->network_size_));
+  entry.done_time = cur_time + send_delay;
+  sender->network_.push_back(entry);
+
+  // Find the delay for crossing the many virtual hops of the network.
+  uint32 transit_delay = GetRandomTransitDelay();
+
+  // Post the packet as a message to be delivered (on our own thread)
+  Packet* p = new Packet(data, data_size, sender->local_addr_);
+  uint32 ts = TimeAfter(send_delay + transit_delay);
+  if (ordered) {
+    // Ensure that new packets arrive after previous ones
+    // TODO: consider ordering on a per-socket basis, since this
+    // introduces artifical delay.
+    ts = TimeMax(ts, network_delay_);
+  }
+  msg_queue_->PostAt(ts, recipient, MSG_ID_PACKET, p);
+  network_delay_ = TimeMax(ts, network_delay_);
+}
+
+void VirtualSocketServer::PurgeNetworkPackets(VirtualSocket* socket,
+                                              uint32 cur_time) {
+  while (!socket->network_.empty() &&
+         (socket->network_.front().done_time <= cur_time)) {
+    ASSERT(socket->network_size_ >= socket->network_.front().size);
+    socket->network_size_ -= socket->network_.front().size;
+    socket->network_.pop_front();
+  }
+}
+
+uint32 VirtualSocketServer::SendDelay(uint32 size) {
+  if (bandwidth_ == 0)
+    return 0;
+  else
+    return 1000 * size / bandwidth_;
+}
+
+#if 0
+void PrintFunction(std::vector<std::pair<double, double> >* f) {
+  return;
+  double sum = 0;
+  for (uint32 i = 0; i < f->size(); ++i) {
+    std::cout << (*f)[i].first << '\t' << (*f)[i].second << std::endl;
+    sum += (*f)[i].second;
+  }
+  if (!f->empty()) {
+    const double mean = sum / f->size();
+    double sum_sq_dev = 0;
+    for (uint32 i = 0; i < f->size(); ++i) {
+      double dev = (*f)[i].second - mean;
+      sum_sq_dev += dev * dev;
+    }
+    std::cout << "Mean = " << mean << " StdDev = "
+              << sqrt(sum_sq_dev / f->size()) << std::endl;
+  }
+}
+#endif  // <unused>
+
+void VirtualSocketServer::UpdateDelayDistribution() {
+  Function* dist = CreateDistribution(delay_mean_, delay_stddev_,
+                                      delay_samples_);
+  // We take a lock just to make sure we don't leak memory.
+  {
+    CritScope cs(&delay_crit_);
+    delete delay_dist_;
+    delay_dist_ = dist;
+  }
+}
+
+static double PI = 4 * atan(1.0);
+
+static double Normal(double x, double mean, double stddev) {
+  double a = (x - mean) * (x - mean) / (2 * stddev * stddev);
+  return exp(-a) / (stddev * sqrt(2 * PI));
+}
+
+#if 0  // static unused gives a warning
+static double Pareto(double x, double min, double k) {
+  if (x < min)
+    return 0;
+  else
+    return k * std::pow(min, k) / std::pow(x, k+1);
+}
+#endif
+
+VirtualSocketServer::Function* VirtualSocketServer::CreateDistribution(
+    uint32 mean, uint32 stddev, uint32 samples) {
+  Function* f = new Function();
+
+  if (0 == stddev) {
+    f->push_back(Point(mean, 1.0));
+  } else {
+    double start = 0;
+    if (mean >= 4 * static_cast<double>(stddev))
+      start = mean - 4 * static_cast<double>(stddev);
+    double end = mean + 4 * static_cast<double>(stddev);
+
+    for (uint32 i = 0; i < samples; i++) {
+      double x = start + (end - start) * i / (samples - 1);
+      double y = Normal(x, mean, stddev);
+      f->push_back(Point(x, y));
+    }
+  }
+  return Resample(Invert(Accumulate(f)), 0, 1, samples);
+}
+
+uint32 VirtualSocketServer::GetRandomTransitDelay() {
+  size_t index = rand() % delay_dist_->size();
+  double delay = (*delay_dist_)[index].second;
+  //LOG_F(LS_INFO) << "random[" << index << "] = " << delay;
+  return static_cast<uint32>(delay);
+}
+
+struct FunctionDomainCmp {
+  bool operator()(const VirtualSocketServer::Point& p1,
+                   const VirtualSocketServer::Point& p2) {
+    return p1.first < p2.first;
+  }
+  bool operator()(double v1, const VirtualSocketServer::Point& p2) {
+    return v1 < p2.first;
+  }
+  bool operator()(const VirtualSocketServer::Point& p1, double v2) {
+    return p1.first < v2;
+  }
+};
+
+VirtualSocketServer::Function* VirtualSocketServer::Accumulate(Function* f) {
+  ASSERT(f->size() >= 1);
+  double v = 0;
+  for (Function::size_type i = 0; i < f->size() - 1; ++i) {
+    double dx = (*f)[i + 1].first - (*f)[i].first;
+    double avgy = ((*f)[i + 1].second + (*f)[i].second) / 2;
+    (*f)[i].second = v;
+    v = v + dx * avgy;
+  }
+  (*f)[f->size()-1].second = v;
+  return f;
+}
+
+VirtualSocketServer::Function* VirtualSocketServer::Invert(Function* f) {
+  for (Function::size_type i = 0; i < f->size(); ++i)
+    std::swap((*f)[i].first, (*f)[i].second);
+
+  std::sort(f->begin(), f->end(), FunctionDomainCmp());
+  return f;
+}
+
+VirtualSocketServer::Function* VirtualSocketServer::Resample(
+    Function* f, double x1, double x2, uint32 samples) {
+  Function* g = new Function();
+
+  for (size_t i = 0; i < samples; i++) {
+    double x = x1 + (x2 - x1) * i / (samples - 1);
+    double y = Evaluate(f, x);
+    g->push_back(Point(x, y));
+  }
+
+  delete f;
+  return g;
+}
+
+double VirtualSocketServer::Evaluate(Function* f, double x) {
+  Function::iterator iter =
+      std::lower_bound(f->begin(), f->end(), x, FunctionDomainCmp());
+  if (iter == f->begin()) {
+    return (*f)[0].second;
+  } else if (iter == f->end()) {
+    ASSERT(f->size() >= 1);
+    return (*f)[f->size() - 1].second;
+  } else if (iter->first == x) {
+    return iter->second;
+  } else {
+    double x1 = (iter - 1)->first;
+    double y1 = (iter - 1)->second;
+    double x2 = iter->first;
+    double y2 = iter->second;
+    return y1 + (y2 - y1) * (x - x1) / (x2 - x1);
+  }
+}
+
+bool VirtualSocketServer::CanInteractWith(VirtualSocket* local,
+                                          VirtualSocket* remote) {
+  if (!local || !remote) {
+    return false;
+  }
+  IPAddress local_ip = local->GetLocalAddress().ipaddr();
+  IPAddress remote_ip = remote->GetLocalAddress().ipaddr();
+  IPAddress local_normalized = local_ip.Normalized();
+  IPAddress remote_normalized = remote_ip.Normalized();
+  // Check if the addresses are the same family after Normalization (turns
+  // mapped IPv6 address into IPv4 addresses).
+  // This will stop unmapped V6 addresses from talking to mapped V6 addresses.
+  if (local_normalized.family() == remote_normalized.family()) {
+    return true;
+  }
+
+  // If ip1 is IPv4 and ip2 is :: and ip2 is not IPV6_V6ONLY.
+  int remote_v6_only = 0;
+  remote->GetOption(Socket::OPT_IPV6_V6ONLY, &remote_v6_only);
+  if (local_ip.family() == AF_INET && !remote_v6_only && IPIsAny(remote_ip)) {
+    return true;
+  }
+  // Same check, backwards.
+  int local_v6_only = 0;
+  local->GetOption(Socket::OPT_IPV6_V6ONLY, &local_v6_only);
+  if (remote_ip.family() == AF_INET && !local_v6_only && IPIsAny(local_ip)) {
+    return true;
+  }
+
+  // Check to see if either socket was explicitly bound to IPv6-any.
+  // These sockets can talk with anyone.
+  if (local_ip.family() == AF_INET6 && local->was_any()) {
+    return true;
+  }
+  if (remote_ip.family() == AF_INET6 && remote->was_any()) {
+    return true;
+  }
+
+  return false;
+}
+
+}  // namespace rtc