net: Add fuzzer for HostResolverImpl.

net/udp/fuzzed_datagram_client_socket.cc

Index: net/udp/fuzzed_datagram_client_socket.cc
diff --git a/net/udp/fuzzed_datagram_client_socket.cc b/net/udp/fuzzed_datagram_client_socket.cc
new file mode 100644
index 0000000000000000000000000000000000000000..800371970f6c44a415120fdc0a48f62afe147629
--- /dev/null
+++ b/net/udp/fuzzed_datagram_client_socket.cc
@@ -0,0 +1,193 @@
+// Copyright 2016 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "net/udp/fuzzed_datagram_client_socket.h"
+
+#include <algorithm>
+
+#include "base/bind.h"
+#include "base/location.h"
+#include "base/logging.h"
+#include "base/strings/string_piece.h"
+#include "base/thread_task_runner_handle.h"
+#include "net/base/fuzzed_data_provider.h"
+#include "net/base/io_buffer.h"
+#include "net/base/ip_address.h"
+#include "net/base/net_errors.h"
+
+namespace net {
+
+// Subset of network errors that can occur on each operation. Less clear cut
+// than TCP errors, so some of these may not actually be possible.
+const Error kConnectErrors[] = {ERR_FAILED, ERR_ADDRESS_UNREACHABLE,
+                                ERR_ACCESS_DENIED};
+const Error kReadErrors[] = {ERR_FAILED, ERR_ADDRESS_UNREACHABLE};
+const Error kWriteErrors[] = {ERR_FAILED, ERR_ADDRESS_UNREACHABLE,
+                              ERR_MSG_TOO_BIG};
+
+FuzzedDatagramClientSocket::FuzzedDatagramClientSocket(
+    FuzzedDataProvider* data_provider)
+    : data_provider_(data_provider), weak_factory_(this) {}
+
+FuzzedDatagramClientSocket::~FuzzedDatagramClientSocket() {}
+
+int FuzzedDatagramClientSocket::Connect(const IPEndPoint& address) {
+  CHECK(!connected_);
+
+  // Decide if the connect attempt succeeds.
+  if (data_provider_->ConsumeBool()) {
+    connected_ = true;
+    remote_address_ = address;
+    return OK;
+  }
+
+  // On failure, return a random connect error.
+  return kConnectErrors[data_provider_->ConsumeValueInRange(

[eroman, 2016/05/17 23:01:34]

Might be handy to have a templetized helper that selects a value given an array
(having seen this in a few places).

[mmenke, 2016/05/19 19:09:46]

Done.  I wasn't sure how to do this, or I would have done it earlier.

+      0, arraysize(kConnectErrors) - 1)];
+}
+
+int FuzzedDatagramClientSocket::ConnectUsingNetwork(
+    NetworkChangeNotifier::NetworkHandle network,
+    const IPEndPoint& address) {
+  CHECK(!connected_);
+  return ERR_NOT_IMPLEMENTED;
+}
+
+int FuzzedDatagramClientSocket::FuzzedDatagramClientSocket::
+    ConnectUsingDefaultNetwork(const IPEndPoint& address) {
+  CHECK(!connected_);
+  return ERR_NOT_IMPLEMENTED;
+}
+
+NetworkChangeNotifier::NetworkHandle
+FuzzedDatagramClientSocket::GetBoundNetwork() const {
+  return NetworkChangeNotifier::kInvalidNetworkHandle;
+}
+
+void FuzzedDatagramClientSocket::Close() {
+  connected_ = false;
+  read_pending_ = false;
+  write_pending_ = false;
+  remote_address_ = IPEndPoint();
+  weak_factory_.InvalidateWeakPtrs();
+}
+
+int FuzzedDatagramClientSocket::GetPeerAddress(IPEndPoint* address) const {
+  if (!connected_)
+    return ERR_SOCKET_NOT_CONNECTED;
+  *address = remote_address_;
+  return OK;
+}
+
+int FuzzedDatagramClientSocket::GetLocalAddress(IPEndPoint* address) const {
+  if (!connected_)
+    return ERR_SOCKET_NOT_CONNECTED;
+  *address = IPEndPoint(IPAddress(1, 2, 3, 4), 43210);
+  return OK;
+}
+
+const BoundNetLog& FuzzedDatagramClientSocket::NetLog() const {
+  return net_log_;
+}
+
+int FuzzedDatagramClientSocket::Read(IOBuffer* buf,
+                                     int buf_len,
+                                     const CompletionCallback& callback) {
+  CHECK(!callback.is_null());
+  CHECK_GT(buf_len, 0);
+  CHECK(!read_pending_);
+
+  // Normally calling this on disconnected sockets is allowed, but code really
+  // shouldn't be doing this.  If it is, it's best to figure out why, and fix
+  // it. Note that |connected_| is only set to false on calls to Close(), not on
+  // errors.
+  CHECK(connected_);
+
+  // Get contents of response.
+  base::StringPiece data(data_provider_->ConsumeBytes(
+      data_provider_->ConsumeValueInRange(0, buf_len)));
+
+  int result;
+  if (data.length() > 0) {
+    // If the response is not empty, consider it a successful read.
+    result = data.length();
+    std::copy(data.begin(), data.end(), buf->data());
+  } else {
+    // If the response is empty, pick a random read error.
+    result = kReadErrors[data_provider_->ConsumeValueInRange(
+        0, arraysize(kReadErrors) - 1)];
+  }
+
+  // Decide if result should be returned synchronously.
+  if (data_provider_->ConsumeBool())
+    return result;
+
+  read_pending_ = true;
+  base::ThreadTaskRunnerHandle::Get()->PostTask(
+      FROM_HERE, base::Bind(&FuzzedDatagramClientSocket::OnReadComplete,
+                            weak_factory_.GetWeakPtr(), callback, result));
+  return ERR_IO_PENDING;
+}
+
+int FuzzedDatagramClientSocket::Write(IOBuffer* buf,
+                                      int buf_len,
+                                      const CompletionCallback& callback) {
+  CHECK(!callback.is_null());
+  CHECK(!write_pending_);
+
+  // Normally this is allowed, but code really shouldn't be doing this - if it
+  // is, it's best to figure out why, and fix it.
+  CHECK(connected_);
+
+  int result;
+  // Decide if success or failure.
+  if (data_provider_->ConsumeBool()) {
+    // On success, everything is written.
+    result = buf_len;
+  } else {
+    // On failure, pick a random write error.
+    result = kWriteErrors[data_provider_->ConsumeValueInRange(
+        0, arraysize(kWriteErrors) - 1)];
+  }
+
+  // Decide if result should be returned synchronously.
+  if (data_provider_->ConsumeBool())
+    return result;
+
+  write_pending_ = true;
+  base::ThreadTaskRunnerHandle::Get()->PostTask(
+      FROM_HERE, base::Bind(&FuzzedDatagramClientSocket::OnWriteComplete,
+                            weak_factory_.GetWeakPtr(), callback, result));
+  return ERR_IO_PENDING;
+}
+
+int FuzzedDatagramClientSocket::SetReceiveBufferSize(int32_t size) {
+  return OK;
+}
+
+int FuzzedDatagramClientSocket::SetSendBufferSize(int32_t size) {
+  return OK;
+}
+
+void FuzzedDatagramClientSocket::OnReadComplete(
+    const net::CompletionCallback& callback,
+    int result) {
+  CHECK(connected_);
+  CHECK(read_pending_);
+
+  read_pending_ = false;
+  callback.Run(result);
+}
+
+void FuzzedDatagramClientSocket::OnWriteComplete(
+    const net::CompletionCallback& callback,
+    int result) {
+  CHECK(connected_);
+  CHECK(write_pending_);
+
+  write_pending_ = false;
+  callback.Run(result);
+}
+
+}  // namespace net