// Copyright (c) 2012 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/spdy/spdy_proxy_client_socket.h"

#include <algorithm>  // min

#include "base/bind.h"
#include "base/bind_helpers.h"
#include "base/logging.h"
#include "base/string_util.h"
#include "base/values.h"
#include "googleurl/src/gurl.h"
#include "net/base/auth.h"
#include "net/base/io_buffer.h"
#include "net/base/net_util.h"
#include "net/http/http_auth_cache.h"
#include "net/http/http_auth_handler_factory.h"
#include "net/http/http_response_headers.h"
#include "net/spdy/spdy_http_utils.h"

namespace net {

SpdyProxyClientSocket::SpdyProxyClientSocket(
    SpdyStream* spdy_stream,
    const std::string& user_agent,
    const HostPortPair& endpoint,
    const GURL& url,
    const HostPortPair& proxy_server,
    const BoundNetLog& source_net_log,
    HttpAuthCache* auth_cache,
    HttpAuthHandlerFactory* auth_handler_factory)
    : next_state_(STATE_DISCONNECTED),
      spdy_stream_(spdy_stream),
      endpoint_(endpoint),
      auth_(
          new HttpAuthController(HttpAuth::AUTH_PROXY,
                                 GURL("https://" + proxy_server.ToString()),
                                 auth_cache,
                                 auth_handler_factory)),
      user_buffer_(NULL),
      write_buffer_len_(0),
      write_bytes_outstanding_(0),
      ALLOW_THIS_IN_INITIALIZER_LIST(weak_factory_(this)),
      net_log_(BoundNetLog::Make(spdy_stream->net_log().net_log(),
                                 NetLog::SOURCE_PROXY_CLIENT_SOCKET)) {
  request_.method = "CONNECT";
  request_.url = url;
  if (!user_agent.empty())
    request_.extra_headers.SetHeader(HttpRequestHeaders::kUserAgent,
                                     user_agent);

  net_log_.BeginEvent(NetLog::TYPE_SOCKET_ALIVE,
                      source_net_log.source().ToEventParametersCallback());
  net_log_.AddEvent(
      NetLog::TYPE_SPDY_PROXY_CLIENT_SESSION,
      spdy_stream->net_log().source().ToEventParametersCallback());

  spdy_stream_->SetDelegate(this);
  was_ever_used_ = spdy_stream_->WasEverUsed();
}

SpdyProxyClientSocket::~SpdyProxyClientSocket() {
  Disconnect();
  net_log_.EndEvent(NetLog::TYPE_SOCKET_ALIVE);
}

const HttpResponseInfo* SpdyProxyClientSocket::GetConnectResponseInfo() const {
  return response_.headers ? &response_ : NULL;
}

const scoped_refptr<HttpAuthController>&
SpdyProxyClientSocket::GetAuthController() const {
  return auth_;
}

int SpdyProxyClientSocket::RestartWithAuth(const CompletionCallback& callback) {
  // A SPDY Stream can only handle a single request, so the underlying
  // stream may not be reused and a new SpdyProxyClientSocket must be
  // created (possibly on top of the same SPDY Session).
  next_state_ = STATE_DISCONNECTED;
  return OK;
}

bool SpdyProxyClientSocket::IsUsingSpdy() const {
  return true;
}

NextProto SpdyProxyClientSocket::GetProtocolNegotiated() const {
  // Save the negotiated protocol
  SSLInfo ssl_info;
  bool was_npn_negotiated;
  NextProto protocol_negotiated;
  spdy_stream_->GetSSLInfo(&ssl_info, &was_npn_negotiated,
                           &protocol_negotiated);
  return protocol_negotiated;
}

HttpStream* SpdyProxyClientSocket::CreateConnectResponseStream() {
  DCHECK(response_stream_.get());
  return response_stream_.release();
}

// Sends a SYN_STREAM frame to the proxy with a CONNECT request
// for the specified endpoint.  Waits for the server to send back
// a SYN_REPLY frame.  OK will be returned if the status is 200.
// ERR_TUNNEL_CONNECTION_FAILED will be returned for any other status.
// In any of these cases, Read() may be called to retrieve the HTTP
// response body.  Any other return values should be considered fatal.
// TODO(rch): handle 407 proxy auth requested correctly, perhaps
// by creating a new stream for the subsequent request.
// TODO(rch): create a more appropriate error code to disambiguate
// the HTTPS Proxy tunnel failure from an HTTP Proxy tunnel failure.
int SpdyProxyClientSocket::Connect(const CompletionCallback& callback) {
  DCHECK(read_callback_.is_null());
  if (next_state_ == STATE_OPEN)
    return OK;

  DCHECK_EQ(STATE_DISCONNECTED, next_state_);
  next_state_ = STATE_GENERATE_AUTH_TOKEN;

  int rv = DoLoop(OK);
  if (rv == ERR_IO_PENDING)
    read_callback_ = callback;
  return rv;
}

void SpdyProxyClientSocket::Disconnect() {
  read_buffer_.clear();
  user_buffer_ = NULL;
  read_callback_.Reset();

  write_buffer_len_ = 0;
  write_bytes_outstanding_ = 0;
  write_callback_.Reset();

  next_state_ = STATE_DISCONNECTED;

  if (spdy_stream_) {
    // This will cause OnClose to be invoked, which takes care of
    // cleaning up all the internal state.
    spdy_stream_->Cancel();
    DCHECK(!spdy_stream_.get());
  }
}

bool SpdyProxyClientSocket::IsConnected() const {
  return next_state_ == STATE_OPEN;
}

bool SpdyProxyClientSocket::IsConnectedAndIdle() const {
  return IsConnected() && read_buffer_.empty() && spdy_stream_->is_idle();
}

const BoundNetLog& SpdyProxyClientSocket::NetLog() const {
  return net_log_;
}

void SpdyProxyClientSocket::SetSubresourceSpeculation() {
  // TODO(rch): what should this implementation be?
}

void SpdyProxyClientSocket::SetOmniboxSpeculation() {
  // TODO(rch): what should this implementation be?
}

bool SpdyProxyClientSocket::WasEverUsed() const {
  return was_ever_used_ || (spdy_stream_ && spdy_stream_->WasEverUsed());
}

bool SpdyProxyClientSocket::UsingTCPFastOpen() const {
  return false;
}

bool SpdyProxyClientSocket::WasNpnNegotiated() const {
  return false;
}

NextProto SpdyProxyClientSocket::GetNegotiatedProtocol() const {
  return kProtoUnknown;
}

bool SpdyProxyClientSocket::GetSSLInfo(SSLInfo* ssl_info) {
  bool was_npn_negotiated;
  NextProto protocol_negotiated;
  return spdy_stream_->GetSSLInfo(ssl_info, &was_npn_negotiated,
                                  &protocol_negotiated);
}

int SpdyProxyClientSocket::Read(IOBuffer* buf, int buf_len,
                                const CompletionCallback& callback) {
  DCHECK(read_callback_.is_null());
  DCHECK(!user_buffer_);

  if (next_state_ == STATE_DISCONNECTED)
    return ERR_SOCKET_NOT_CONNECTED;

  if (next_state_ == STATE_CLOSED && read_buffer_.empty()) {
    return 0;
  }

  DCHECK(next_state_ == STATE_OPEN || next_state_ == STATE_CLOSED);
  DCHECK(buf);
  user_buffer_ = new DrainableIOBuffer(buf, buf_len);
  int result = PopulateUserReadBuffer();
  if (result == 0) {
    DCHECK(!callback.is_null());
    read_callback_ = callback;
    return ERR_IO_PENDING;
  }
  user_buffer_ = NULL;
  return result;
}

int SpdyProxyClientSocket::PopulateUserReadBuffer() {
  if (!user_buffer_)
    return ERR_IO_PENDING;

  int bytes_read = 0;
  while (!read_buffer_.empty() && user_buffer_->BytesRemaining() > 0) {
    scoped_refptr<DrainableIOBuffer> data = read_buffer_.front();
    const int bytes_to_copy = std::min(user_buffer_->BytesRemaining(),
                                       data->BytesRemaining());
    memcpy(user_buffer_->data(), data->data(), bytes_to_copy);
    user_buffer_->DidConsume(bytes_to_copy);
    bytes_read += bytes_to_copy;
    if (data->BytesRemaining() == bytes_to_copy) {
      // Consumed all data from this buffer
      read_buffer_.pop_front();
    } else {
      data->DidConsume(bytes_to_copy);
    }
  }

  if (bytes_read > 0 && spdy_stream_)
    spdy_stream_->IncreaseRecvWindowSize(bytes_read);

  return user_buffer_->BytesConsumed();
}

int SpdyProxyClientSocket::Write(IOBuffer* buf, int buf_len,
                                 const CompletionCallback& callback) {
  DCHECK(write_callback_.is_null());
  if (next_state_ != STATE_OPEN)
    return ERR_SOCKET_NOT_CONNECTED;

  DCHECK(spdy_stream_);
  write_bytes_outstanding_= buf_len;
  if (buf_len <= kMaxSpdyFrameChunkSize) {
    spdy_stream_->QueueStreamData(buf, buf_len, DATA_FLAG_NONE);
    net_log_.AddByteTransferEvent(NetLog::TYPE_SOCKET_BYTES_SENT,
                                  buf_len, buf->data());
    write_callback_ = callback;
    write_buffer_len_ = buf_len;
    return ERR_IO_PENDING;
  }

  // Since a SPDY Data frame can only include kMaxSpdyFrameChunkSize bytes
  // we need to send multiple data frames
  for (int i = 0; i < buf_len; i += kMaxSpdyFrameChunkSize) {
    int len = std::min(kMaxSpdyFrameChunkSize, buf_len - i);
    scoped_refptr<DrainableIOBuffer> iobuf(new DrainableIOBuffer(buf, i + len));
    iobuf->SetOffset(i);
    spdy_stream_->QueueStreamData(iobuf, len, DATA_FLAG_NONE);
    net_log_.AddByteTransferEvent(NetLog::TYPE_SOCKET_BYTES_SENT,
                                  len, buf->data());
  }
  if (write_bytes_outstanding_ > 0) {
    write_callback_ = callback;
    write_buffer_len_ = buf_len;
    return ERR_IO_PENDING;
  } else {
    return buf_len;
  }
}

bool SpdyProxyClientSocket::SetReceiveBufferSize(int32 size) {
  // Since this StreamSocket sits on top of a shared SpdySession, it
  // is not safe for callers to set change this underlying socket.
  return false;
}

bool SpdyProxyClientSocket::SetSendBufferSize(int32 size) {
  // Since this StreamSocket sits on top of a shared SpdySession, it
  // is not safe for callers to set change this underlying socket.
  return false;
}

int SpdyProxyClientSocket::GetPeerAddress(IPEndPoint* address) const {
  if (!IsConnected())
    return ERR_SOCKET_NOT_CONNECTED;
  return spdy_stream_->GetPeerAddress(address);
}

int SpdyProxyClientSocket::GetLocalAddress(IPEndPoint* address) const {
  if (!IsConnected())
    return ERR_SOCKET_NOT_CONNECTED;
  return spdy_stream_->GetLocalAddress(address);
}

void SpdyProxyClientSocket::LogBlockedTunnelResponse() const {
  ProxyClientSocket::LogBlockedTunnelResponse(
      response_.headers->response_code(),
      request_.url,
      /* is_https_proxy = */ true);
}

void SpdyProxyClientSocket::OnIOComplete(int result) {
  DCHECK_NE(STATE_DISCONNECTED, next_state_);
  int rv = DoLoop(result);
  if (rv != ERR_IO_PENDING) {
    CompletionCallback c = read_callback_;
    read_callback_.Reset();
    c.Run(rv);
  }
}

int SpdyProxyClientSocket::DoLoop(int last_io_result) {
  DCHECK_NE(next_state_, STATE_DISCONNECTED);
  int rv = last_io_result;
  do {
    State state = next_state_;
    next_state_ = STATE_DISCONNECTED;
    switch (state) {
      case STATE_GENERATE_AUTH_TOKEN:
        DCHECK_EQ(OK, rv);
        rv = DoGenerateAuthToken();
        break;
      case STATE_GENERATE_AUTH_TOKEN_COMPLETE:
        rv = DoGenerateAuthTokenComplete(rv);
        break;
      case STATE_SEND_REQUEST:
        DCHECK_EQ(OK, rv);
        net_log_.BeginEvent(NetLog::TYPE_HTTP_TRANSACTION_TUNNEL_SEND_REQUEST);
        rv = DoSendRequest();
        break;
      case STATE_SEND_REQUEST_COMPLETE:
        net_log_.EndEventWithNetErrorCode(
            NetLog::TYPE_HTTP_TRANSACTION_TUNNEL_SEND_REQUEST, rv);
        rv = DoSendRequestComplete(rv);
        if (rv >= 0 || rv == ERR_IO_PENDING) {
          // Emit extra event so can use the same events as
          // HttpProxyClientSocket.
          net_log_.BeginEvent(
              NetLog::TYPE_HTTP_TRANSACTION_TUNNEL_READ_HEADERS);
        }
        break;
      case STATE_READ_REPLY_COMPLETE:
        rv = DoReadReplyComplete(rv);
        net_log_.EndEventWithNetErrorCode(
            NetLog::TYPE_HTTP_TRANSACTION_TUNNEL_READ_HEADERS, rv);
        break;
      default:
        NOTREACHED() << "bad state";
        rv = ERR_UNEXPECTED;
        break;
    }
  } while (rv != ERR_IO_PENDING && next_state_ != STATE_DISCONNECTED &&
           next_state_ != STATE_OPEN);
  return rv;
}

int SpdyProxyClientSocket::DoGenerateAuthToken() {
  next_state_ = STATE_GENERATE_AUTH_TOKEN_COMPLETE;
  return auth_->MaybeGenerateAuthToken(
      &request_,
      base::Bind(&SpdyProxyClientSocket::OnIOComplete,
                 weak_factory_.GetWeakPtr()),
      net_log_);
}

int SpdyProxyClientSocket::DoGenerateAuthTokenComplete(int result) {
  DCHECK_NE(ERR_IO_PENDING, result);
  if (result == OK)
    next_state_ = STATE_SEND_REQUEST;
  return result;
}

int SpdyProxyClientSocket::DoSendRequest() {
  next_state_ = STATE_SEND_REQUEST_COMPLETE;

  // Add Proxy-Authentication header if necessary.
  HttpRequestHeaders authorization_headers;
  if (auth_->HaveAuth()) {
    auth_->AddAuthorizationHeader(&authorization_headers);
  }

  std::string request_line;
  HttpRequestHeaders request_headers;
  BuildTunnelRequest(request_, authorization_headers, endpoint_, &request_line,
                     &request_headers);

  net_log_.AddEvent(
      NetLog::TYPE_HTTP_TRANSACTION_SEND_TUNNEL_HEADERS,
      base::Bind(&HttpRequestHeaders::NetLogCallback,
                 base::Unretained(&request_headers),
                 &request_line));

  request_.extra_headers.MergeFrom(request_headers);
  scoped_ptr<SpdyHeaderBlock> headers(new SpdyHeaderBlock());
  CreateSpdyHeadersFromHttpRequest(request_, request_headers, headers.get(),
                                   spdy_stream_->GetProtocolVersion(), true);
  // Reset the URL to be the endpoint of the connection
  if (spdy_stream_->GetProtocolVersion() > 2) {
    (*headers)[":path"] = endpoint_.ToString();
    headers->erase(":scheme");
  } else {
    (*headers)["url"] = endpoint_.ToString();
    headers->erase("scheme");
  }
  spdy_stream_->set_spdy_headers(headers.Pass());

  return spdy_stream_->SendRequest(true);
}

int SpdyProxyClientSocket::DoSendRequestComplete(int result) {
  if (result < 0)
    return result;

  // Wait for SYN_REPLY frame from the server
  next_state_ = STATE_READ_REPLY_COMPLETE;
  return ERR_IO_PENDING;
}

int SpdyProxyClientSocket::DoReadReplyComplete(int result) {
  // We enter this method directly from DoSendRequestComplete, since
  // we are notified by a callback when the SYN_REPLY frame arrives

  if (result < 0)
    return result;

  // Require the "HTTP/1.x" status line for SSL CONNECT.
  if (response_.headers->GetParsedHttpVersion() < HttpVersion(1, 0))
    return ERR_TUNNEL_CONNECTION_FAILED;

  net_log_.AddEvent(
      NetLog::TYPE_HTTP_TRANSACTION_READ_TUNNEL_RESPONSE_HEADERS,
      base::Bind(&HttpResponseHeaders::NetLogCallback, response_.headers));

  switch (response_.headers->response_code()) {
    case 200:  // OK
      next_state_ = STATE_OPEN;
      return OK;

    case 302:  // Found / Moved Temporarily
      // Try to return a sanitized response so we can follow auth redirects.
      // If we can't, fail the tunnel connection.
      if (SanitizeProxyRedirect(&response_, request_.url)) {
        // Immediately hand off our SpdyStream to a newly created
        // SpdyHttpStream so that any subsequent SpdyFrames are processed in
        // the context of the HttpStream, not the socket.
        DCHECK(spdy_stream_);
        SpdyStream* stream = spdy_stream_;
        spdy_stream_ = NULL;
        response_stream_.reset(new SpdyHttpStream(NULL, false));
        response_stream_->InitializeWithExistingStream(stream);
        next_state_ = STATE_DISCONNECTED;
        return ERR_HTTPS_PROXY_TUNNEL_RESPONSE;
      } else {
        LogBlockedTunnelResponse();
        return ERR_TUNNEL_CONNECTION_FAILED;
      }

    case 407:  // Proxy Authentication Required
      next_state_ = STATE_OPEN;
      return HandleProxyAuthChallenge(auth_, &response_, net_log_);

    default:
      // Ignore response to avoid letting the proxy impersonate the target
      // server.  (See http://crbug.com/137891.)
      LogBlockedTunnelResponse();
      return ERR_TUNNEL_CONNECTION_FAILED;
  }
}

// SpdyStream::Delegate methods:
// Called when SYN frame has been sent.
// Returns true if no more data to be sent after SYN frame.
bool SpdyProxyClientSocket::OnSendHeadersComplete(int status) {
  DCHECK_EQ(next_state_, STATE_SEND_REQUEST_COMPLETE);

  OnIOComplete(status);

  // We return true here so that we send |spdy_stream_| into
  // STATE_OPEN (ala WebSockets).
  return true;
}

int SpdyProxyClientSocket::OnSendBody() {
  // Because we use |spdy_stream_| via STATE_OPEN (ala WebSockets)
  // OnSendBody() should never be called.
  NOTREACHED();
  return ERR_UNEXPECTED;
}

int SpdyProxyClientSocket::OnSendBodyComplete(int /*status*/, bool* /*eof*/) {
  // Because we use |spdy_stream_| via STATE_OPEN (ala WebSockets)
  // OnSendBodyComplete() should never be called.
  NOTREACHED();
  return ERR_UNEXPECTED;
}

int SpdyProxyClientSocket::OnResponseReceived(
    const SpdyHeaderBlock& response,
    base::Time response_time,
    int status) {
  // If we've already received the reply, existing headers are too late.
  // TODO(mbelshe): figure out a way to make HEADERS frames useful after the
  //                initial response.
  if (next_state_ != STATE_READ_REPLY_COMPLETE)
    return OK;

  // Save the response
  if (!SpdyHeadersToHttpResponse(
          response, spdy_stream_->GetProtocolVersion(), &response_))
      return ERR_INCOMPLETE_SPDY_HEADERS;

  OnIOComplete(status);
  return OK;
}

void SpdyProxyClientSocket::OnHeadersSent() {
  // Proxy client sockets don't send any HEADERS frame.
  NOTREACHED();
}

// Called when data is received.
int SpdyProxyClientSocket::OnDataReceived(const char* data, int length) {
  net_log_.AddByteTransferEvent(NetLog::TYPE_SOCKET_BYTES_RECEIVED,
                                length, data);
  if (length > 0) {
    // Save the received data.
    scoped_refptr<IOBuffer> io_buffer(new IOBuffer(length));
    memcpy(io_buffer->data(), data, length);
    read_buffer_.push_back(
        make_scoped_refptr(new DrainableIOBuffer(io_buffer, length)));
  }

  if (!read_callback_.is_null()) {
    int rv = PopulateUserReadBuffer();
    CompletionCallback c = read_callback_;
    read_callback_.Reset();
    user_buffer_ = NULL;
    c.Run(rv);
  }
  return OK;
}

void SpdyProxyClientSocket::OnDataSent(int length)  {
  DCHECK(!write_callback_.is_null());

  write_bytes_outstanding_ -= length;

  DCHECK_GE(write_bytes_outstanding_, 0);

  if (write_bytes_outstanding_ == 0) {
    int rv = write_buffer_len_;
    write_buffer_len_ = 0;
    write_bytes_outstanding_ = 0;
    CompletionCallback c = write_callback_;
    write_callback_.Reset();
    c.Run(rv);
  }
}

void SpdyProxyClientSocket::OnClose(int status)  {
  DCHECK(spdy_stream_);
  was_ever_used_ = spdy_stream_->WasEverUsed();
  spdy_stream_ = NULL;

  bool connecting = next_state_ != STATE_DISCONNECTED &&
      next_state_ < STATE_OPEN;
  if (next_state_ == STATE_OPEN)
    next_state_ = STATE_CLOSED;
  else
    next_state_ = STATE_DISCONNECTED;

  base::WeakPtr<SpdyProxyClientSocket> weak_ptr = weak_factory_.GetWeakPtr();
  CompletionCallback write_callback = write_callback_;
  write_callback_.Reset();
  write_buffer_len_ = 0;
  write_bytes_outstanding_ = 0;

  // If we're in the middle of connecting, we need to make sure
  // we invoke the connect callback.
  if (connecting) {
    DCHECK(!read_callback_.is_null());
    CompletionCallback read_callback = read_callback_;
    read_callback_.Reset();
    read_callback.Run(status);
  } else if (!read_callback_.is_null()) {
    // If we have a read_callback_, the we need to make sure we call it back.
    OnDataReceived(NULL, 0);
  }
  // This may have been deleted by read_callback_, so check first.
  if (weak_ptr && !write_callback.is_null())
    write_callback.Run(ERR_CONNECTION_CLOSED);
}

}  // namespace net