text: /*
   * nghttp2 - HTTP/2 C Library
   *
   * Copyright (c) 2012 Tatsuhiro Tsujikawa
   *
   * Permission is hereby granted, free of charge, to any person obtaining
   * a copy of this software and associated documentation files (the
   * "Software"), to deal in the Software without restriction, including
   * without limitation the rights to use, copy, modify, merge, publish,
   * distribute, sublicense, and/or sell copies of the Software, and to
   * permit persons to whom the Software is furnished to do so, subject to
   * the following conditions:
   *
   * The above copyright notice and this permission notice shall be
   * included in all copies or substantial portions of the Software.
   *
   * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
   * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
   * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
   * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
   * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
   * OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
   * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
   */
  #include "shrpx_http2_downstream_connection.h"
  
  #ifdef HAVE_UNISTD_H
  #  include <unistd.h>
  #endif // HAVE_UNISTD_H
  
  #include "llhttp.h"
  
  #include "shrpx_client_handler.h"
  #include "shrpx_upstream.h"
  #include "shrpx_downstream.h"
  #include "shrpx_config.h"
  #include "shrpx_error.h"
  #include "shrpx_http.h"
  #include "shrpx_http2_session.h"
  #include "shrpx_worker.h"
  #include "shrpx_log.h"
  #include "http2.h"
  #include "util.h"
  #include "ssl_compat.h"
  
  using namespace nghttp2;
  
  namespace shrpx {
  
  Http2DownstreamConnection::Http2DownstreamConnection(Http2Session *http2session)
      : dlnext(nullptr),
        dlprev(nullptr),
        http2session_(http2session),
        sd_(nullptr) {}
  
  Http2DownstreamConnection::~Http2DownstreamConnection() {
    if (LOG_ENABLED(INFO)) {
      DCLOG(INFO, this) << "Deleting";
    }
    if (downstream_) {
      downstream_->disable_downstream_rtimer();
      downstream_->disable_downstream_wtimer();
  
      uint32_t error_code;
      if (downstream_->get_request_state() == DownstreamState::STREAM_CLOSED &&
          downstream_->get_upgraded()) {
        // For upgraded connection, send NO_ERROR.  Should we consider
        // request states other than DownstreamState::STREAM_CLOSED ?
        error_code = NGHTTP2_NO_ERROR;
      } else {
        error_code = NGHTTP2_INTERNAL_ERROR;
      }
  
      if (http2session_->get_state() == Http2SessionState::CONNECTED &&
          downstream_->get_downstream_stream_id() != -1) {
        submit_rst_stream(downstream_, error_code);
  
        auto &resp = downstream_->response();
  
        http2session_->consume(downstream_->get_downstream_stream_id(),
                               resp.unconsumed_body_length);
  
        resp.unconsumed_body_length = 0;
  
        http2session_->signal_write();
      }
    }
    http2session_->remove_downstream_connection(this);
  
    if (LOG_ENABLED(INFO)) {
      DCLOG(INFO, this) << "Deleted";
    }
  }
  
  int Http2DownstreamConnection::attach_downstream(Downstream *downstream) {
    if (LOG_ENABLED(INFO)) {
      DCLOG(INFO, this) << "Attaching to DOWNSTREAM:" << downstream;
    }
    http2session_->add_downstream_connection(this);
    http2session_->signal_write();
  
    downstream_ = downstream;
    downstream_->reset_downstream_rtimer();
  
    auto &req = downstream_->request();
  
    // HTTP/2 disables HTTP Upgrade.
    if (req.method != HTTP_CONNECT && req.connect_proto == ConnectProto::NONE) {
      req.upgrade_request = false;
    }
  
    return 0;
  }
  
  void Http2DownstreamConnection::detach_downstream(Downstream *downstream) {
    if (LOG_ENABLED(INFO)) {
      DCLOG(INFO, this) << "Detaching from DOWNSTREAM:" << downstream;
    }
  
    auto &resp = downstream_->response();
  
    if (downstream_->get_downstream_stream_id() != -1) {
      if (submit_rst_stream(downstream) == 0) {
        http2session_->signal_write();
      }
  
      http2session_->consume(downstream_->get_downstream_stream_id(),
                             resp.unconsumed_body_length);
  
      resp.unconsumed_body_length = 0;
  
      http2session_->signal_write();
    }
  
    downstream->disable_downstream_rtimer();
    downstream->disable_downstream_wtimer();
    downstream_ = nullptr;
  }
  
  int Http2DownstreamConnection::submit_rst_stream(Downstream *downstream,
                                                   uint32_t error_code) {
    int rv = -1;
    if (http2session_->get_state() == Http2SessionState::CONNECTED &&
        downstream->get_downstream_stream_id() != -1) {
      switch (downstream->get_response_state()) {
      case DownstreamState::MSG_RESET:
      case DownstreamState::MSG_BAD_HEADER:
      case DownstreamState::MSG_COMPLETE:
        break;
      default:
        if (LOG_ENABLED(INFO)) {
          DCLOG(INFO, this) << "Submit RST_STREAM for DOWNSTREAM:" << downstream
                            << ", stream_id="
                            << downstream->get_downstream_stream_id()
                            << ", error_code=" << error_code;
        }
        rv = http2session_->submit_rst_stream(
            downstream->get_downstream_stream_id(), error_code);
      }
    }
    return rv;
  }
  
  namespace {
  ssize_t http2_data_read_callback(nghttp2_session *session, int32_t stream_id,
                                   uint8_t *buf, size_t length,
                                   uint32_t *data_flags,
                                   nghttp2_data_source *source, void *user_data) {
    int rv;
    auto sd = static_cast<StreamData *>(
        nghttp2_session_get_stream_user_data(session, stream_id));
    if (!sd || !sd->dconn) {
      return NGHTTP2_ERR_DEFERRED;
    }
    auto dconn = sd->dconn;
    auto downstream = dconn->get_downstream();
    if (!downstream) {
      // In this case, RST_STREAM should have been issued. But depending
      // on the priority, DATA frame may come first.
      return NGHTTP2_ERR_DEFERRED;
    }
    const auto &req = downstream->request();
    auto input = downstream->get_request_buf();
  
    auto nread = std::min(input->rleft(), length);
    auto input_empty = input->rleft() == nread;
  
    *data_flags |= NGHTTP2_DATA_FLAG_NO_COPY;
  
    if (input_empty &&
        downstream->get_request_state() == DownstreamState::MSG_COMPLETE &&
        // If connection is upgraded, don't set EOF flag, since HTTP/1
        // will set MSG_COMPLETE to request state after upgrade response
        // header is seen.
        (!req.upgrade_request ||
         (downstream->get_response_state() == DownstreamState::HEADER_COMPLETE &&
          !downstream->get_upgraded()))) {
  
      *data_flags |= NGHTTP2_DATA_FLAG_EOF;
  
      const auto &trailers = req.fs.trailers();
      if (!trailers.empty()) {
        std::vector<nghttp2_nv> nva;
        nva.reserve(trailers.size());
        http2::copy_headers_to_nva_nocopy(nva, trailers, http2::HDOP_STRIP_ALL);
        if (!nva.empty()) {
          rv = nghttp2_submit_trailer(session, stream_id, nva.data(), nva.size());
          if (rv != 0) {
            if (nghttp2_is_fatal(rv)) {
              return NGHTTP2_ERR_CALLBACK_FAILURE;
            }
          } else {
            *data_flags |= NGHTTP2_DATA_FLAG_NO_END_STREAM;
          }
        }
      }
    }
  
    if (nread == 0 && (*data_flags & NGHTTP2_DATA_FLAG_EOF) == 0) {
      downstream->disable_downstream_wtimer();
  
      return NGHTTP2_ERR_DEFERRED;
    }
  
    return nread;
  }
  } // namespace
  
  int Http2DownstreamConnection::push_request_headers() {
    int rv;
    if (!downstream_) {
      return 0;
    }
    if (!http2session_->can_push_request(downstream_)) {
      // The HTTP2 session to the backend has not been established or
      // connection is now being checked.  This function will be called
      // again just after it is established.
      downstream_->set_request_pending(true);
      http2session_->start_checking_connection();
      return 0;
    }
  
    downstream_->set_request_pending(false);
  
    const auto &req = downstream_->request();
  
    if (req.connect_proto != ConnectProto::NONE &&
        !http2session_->get_allow_connect_proto()) {
      return -1;
    }
  
    auto &balloc = downstream_->get_block_allocator();
  
    auto config = get_config();
    auto &httpconf = config->http;
    auto &http2conf = config->http2;
  
    auto no_host_rewrite = httpconf.no_host_rewrite || config->http2_proxy ||
                           req.regular_connect_method();
  
    // http2session_ has already in CONNECTED state, so we can get
    // addr_idx here.
    const auto &downstream_hostport = http2session_->get_addr()->hostport;
  
    // For HTTP/1.0 request, there is no authority in request.  In that
    // case, we use backend server's host nonetheless.
    auto authority = StringRef(downstream_hostport);
  
    if (no_host_rewrite && !req.authority.empty()) {
      authority = req.authority;
    }
  
    downstream_->set_request_downstream_host(authority);
  
    size_t num_cookies = 0;
    if (!http2conf.no_cookie_crumbling) {
      num_cookies = downstream_->count_crumble_request_cookie();
    }
  
    // 11 means:
    // 1. :method
    // 2. :scheme
    // 3. :path
    // 4. :authority (or host)
    // 5. :protocol (optional)
    // 6. via (optional)
    // 7. x-forwarded-for (optional)
    // 8. x-forwarded-proto (optional)
    // 9. te (optional)
    // 10. forwarded (optional)
    // 11. early-data (optional)
    auto nva = std::vector<nghttp2_nv>();
    nva.reserve(req.fs.headers().size() + 11 + num_cookies +
                httpconf.add_request_headers.size());
  
    if (req.connect_proto == ConnectProto::WEBSOCKET) {
      nva.push_back(http2::make_nv_ll(":method", "CONNECT"));
      nva.push_back(http2::make_nv_ll(":protocol", "websocket"));
    } else {
      nva.push_back(http2::make_nv_ls_nocopy(
          ":method", http2::to_method_string(req.method)));
    }
  
    if (!req.regular_connect_method()) {
      assert(!req.scheme.empty());
  
      auto addr = http2session_->get_addr();
      assert(addr);
      // We will handle more protocol scheme upgrade in the future.
      if (addr->tls && addr->upgrade_scheme && req.scheme == "http") {
        nva.push_back(http2::make_nv_ll(":scheme", "https"));
      } else {
        nva.push_back(http2::make_nv_ls_nocopy(":scheme", req.scheme));
      }
  
      if (req.method == HTTP_OPTIONS && req.path.empty()) {
        nva.push_back(http2::make_nv_ll(":path", "*"));
      } else {
        nva.push_back(http2::make_nv_ls_nocopy(":path", req.path));
      }
  
      if (!req.no_authority || req.connect_proto != ConnectProto::NONE) {
        nva.push_back(http2::make_nv_ls_nocopy(":authority", authority));
      } else {
        nva.push_back(http2::make_nv_ls_nocopy("host", authority));
      }
    } else {
      nva.push_back(http2::make_nv_ls_nocopy(":authority", authority));
    }
  
    auto &fwdconf = httpconf.forwarded;
    auto &xffconf = httpconf.xff;
    auto &xfpconf = httpconf.xfp;
    auto &earlydataconf = httpconf.early_data;
  
    uint32_t build_flags =
        (fwdconf.strip_incoming ? http2::HDOP_STRIP_FORWARDED : 0) |
        (xffconf.strip_incoming ? http2::HDOP_STRIP_X_FORWARDED_FOR : 0) |
        (xfpconf.strip_incoming ? http2::HDOP_STRIP_X_FORWARDED_PROTO : 0) |
        (earlydataconf.strip_incoming ? http2::HDOP_STRIP_EARLY_DATA : 0) |
        http2::HDOP_STRIP_SEC_WEBSOCKET_KEY;
  
    http2::copy_headers_to_nva_nocopy(nva, req.fs.headers(), build_flags);
  
    if (!http2conf.no_cookie_crumbling) {
      downstream_->crumble_request_cookie(nva);
    }
  
    auto upstream = downstream_->get_upstream();
    auto handler = upstream->get_client_handler();
  
  #if OPENSSL_1_1_1_API
    auto conn = handler->get_connection();
  
    if (conn->tls.ssl && !SSL_is_init_finished(conn->tls.ssl)) {
      nva.push_back(http2::make_nv_ll("early-data", "1"));
    }
  #endif // OPENSSL_1_1_1_API
  
    auto fwd =
        fwdconf.strip_incoming ? nullptr : req.fs.header(http2::HD_FORWARDED);
  
    if (fwdconf.params) {
      auto params = fwdconf.params;
  
      if (config->http2_proxy || req.regular_connect_method()) {
        params &= ~FORWARDED_PROTO;
      }
  
      auto value = http::create_forwarded(
          balloc, params, handler->get_forwarded_by(),
          handler->get_forwarded_for(), req.authority, req.scheme);
  
      if (fwd || !value.empty()) {
        if (fwd) {
          if (value.empty()) {
            value = fwd->value;
          } else {
            value = concat_string_ref(balloc, fwd->value,
                                      StringRef::from_lit(", "), value);
          }
        }
  
        nva.push_back(http2::make_nv_ls_nocopy("forwarded", value));
      }
    } else if (fwd) {
      nva.push_back(http2::make_nv_ls_nocopy("forwarded", fwd->value));
    }
  
    auto xff = xffconf.strip_incoming ? nullptr
                                      : req.fs.header(http2::HD_X_FORWARDED_FOR);
  
    if (xffconf.add) {
      StringRef xff_value;
      const auto &addr = upstream->get_client_handler()->get_ipaddr();
      if (xff) {
        xff_value = concat_string_ref(balloc, xff->value,
                                      StringRef::from_lit(", "), addr);
      } else {
        xff_value = addr;
      }
      nva.push_back(http2::make_nv_ls_nocopy("x-forwarded-for", xff_value));
    } else if (xff) {
      nva.push_back(http2::make_nv_ls_nocopy("x-forwarded-for", xff->value));
    }
  
    if (!config->http2_proxy && !req.regular_connect_method()) {
      auto xfp = xfpconf.strip_incoming
                     ? nullptr
                     : req.fs.header(http2::HD_X_FORWARDED_PROTO);
  
      if (xfpconf.add) {
        StringRef xfp_value;
        // We use same protocol with :scheme header field
        if (xfp) {
          xfp_value = concat_string_ref(balloc, xfp->value,
                                        StringRef::from_lit(", "), req.scheme);
        } else {
          xfp_value = req.scheme;
        }
        nva.push_back(http2::make_nv_ls_nocopy("x-forwarded-proto", xfp_value));
      } else if (xfp) {
        nva.push_back(http2::make_nv_ls_nocopy("x-forwarded-proto", xfp->value));
      }
    }
  
    auto via = req.fs.header(http2::HD_VIA);
    if (httpconf.no_via) {
      if (via) {
        nva.push_back(http2::make_nv_ls_nocopy("via", (*via).value));
      }
    } else {
      size_t vialen = 16;
      if (via) {
        vialen += via->value.size() + 2;
      }
  
      auto iov = make_byte_ref(balloc, vialen + 1);
      auto p = iov.base;
  
      if (via) {
        p = std::copy(std::begin(via->value), std::end(via->value), p);
        p = util::copy_lit(p, ", ");
      }
      p = http::create_via_header_value(p, req.http_major, req.http_minor);
      *p = '\0';
  
      nva.push_back(http2::make_nv_ls_nocopy("via", StringRef{iov.base, p}));
    }
  
    auto te = req.fs.header(http2::HD_TE);
    // HTTP/1 upstream request can contain keyword other than
    // "trailers".  We just forward "trailers".
    // TODO more strict handling required here.
    if (te && http2::contains_trailers(te->value)) {
      nva.push_back(http2::make_nv_ll("te", "trailers"));
    }
  
    for (auto &p : httpconf.add_request_headers) {
      nva.push_back(http2::make_nv_nocopy(p.name, p.value));
    }
  
    if (LOG_ENABLED(INFO)) {
      std::stringstream ss;
      for (auto &nv : nva) {
        if (util::streq_l("authorization", nv.name, nv.namelen)) {
          ss << TTY_HTTP_HD << StringRef{nv.name, nv.namelen} << TTY_RST
             << ": <redacted>\n";
          continue;
        }
        ss << TTY_HTTP_HD << StringRef{nv.name, nv.namelen} << TTY_RST << ": "
           << StringRef{nv.value, nv.valuelen} << "\n";
      }
      DCLOG(INFO, this) << "HTTP request headers\n" << ss.str();
    }
  
    auto transfer_encoding = req.fs.header(http2::HD_TRANSFER_ENCODING);
  
    nghttp2_data_provider *data_prdptr = nullptr;
    nghttp2_data_provider data_prd;
  
    // Add body as long as transfer-encoding is given even if
    // req.fs.content_length == 0 to forward trailer fields.
    if (req.method == HTTP_CONNECT || req.connect_proto != ConnectProto::NONE ||
        transfer_encoding || req.fs.content_length > 0 || req.http2_expect_body) {
      // Request-body is expected.
      data_prd = {{}, http2_data_read_callback};
      data_prdptr = &data_prd;
    }
  
    rv = http2session_->submit_request(this, nva.data(), nva.size(), data_prdptr);
    if (rv != 0) {
      DCLOG(FATAL, this) << "nghttp2_submit_request() failed";
      return -1;
    }
  
    if (data_prdptr) {
      downstream_->reset_downstream_wtimer();
    }
  
    http2session_->signal_write();
    return 0;
  }
  
  int Http2DownstreamConnection::push_upload_data_chunk(const uint8_t *data,
                                                        size_t datalen) {
    if (!downstream_->get_request_header_sent()) {
      auto output = downstream_->get_blocked_request_buf();
      auto &req = downstream_->request();
      output->append(data, datalen);
      req.unconsumed_body_length += datalen;
      return 0;
    }
  
    int rv;
    auto output = downstream_->get_request_buf();
    output->append(data, datalen);
    if (downstream_->get_downstream_stream_id() != -1) {
      rv = http2session_->resume_data(this);
      if (rv != 0) {
        return -1;
      }
  
      downstream_->ensure_downstream_wtimer();
  
      http2session_->signal_write();
    }
    return 0;
  }
  
  int Http2DownstreamConnection::end_upload_data() {
    if (!downstream_->get_request_header_sent()) {
      downstream_->set_blocked_request_data_eof(true);
      return 0;
    }
  
    int rv;
    if (downstream_->get_downstream_stream_id() != -1) {
      rv = http2session_->resume_data(this);
      if (rv != 0) {
        return -1;
      }
  
      downstream_->ensure_downstream_wtimer();
  
      http2session_->signal_write();
    }
    return 0;
  }
  
  int Http2DownstreamConnection::resume_read(IOCtrlReason reason,
                                             size_t consumed) {
    int rv;
  
    if (http2session_->get_state() != Http2SessionState::CONNECTED) {
      return 0;
    }
  
    if (!downstream_ || downstream_->get_downstream_stream_id() == -1) {
      return 0;
    }
  
    if (consumed > 0) {
      rv = http2session_->consume(downstream_->get_downstream_stream_id(),
                                  consumed);
  
      if (rv != 0) {
        return -1;
      }
  
      auto &resp = downstream_->response();
  
      resp.unconsumed_body_length -= consumed;
  
      http2session_->signal_write();
    }
  
    return 0;
  }
  
  int Http2DownstreamConnection::on_read() { return 0; }
  
  int Http2DownstreamConnection::on_write() { return 0; }
  
  void Http2DownstreamConnection::attach_stream_data(StreamData *sd) {
    // It is possible sd->dconn is not NULL. sd is detached when
    // on_stream_close_callback. Before that, after MSG_COMPLETE is set
    // to Downstream::set_response_state(), upstream's readcb is called
    // and execution path eventually could reach here. Since the
    // response was already handled, we just detach sd.
    detach_stream_data();
    sd_ = sd;
    sd_->dconn = this;
  }
  
  StreamData *Http2DownstreamConnection::detach_stream_data() {
    if (sd_) {
      auto sd = sd_;
      sd_ = nullptr;
      sd->dconn = nullptr;
      return sd;
    }
    return nullptr;
  }
  
  int Http2DownstreamConnection::on_timeout() {
    if (!downstream_) {
      return 0;
    }
  
    return submit_rst_stream(downstream_, NGHTTP2_NO_ERROR);
  }
  
  const std::shared_ptr<DownstreamAddrGroup> &
  Http2DownstreamConnection::get_downstream_addr_group() const {
    return http2session_->get_downstream_addr_group();
  }
  
  DownstreamAddr *Http2DownstreamConnection::get_addr() const { return nullptr; }
  
  } // namespace shrpx
  