nghttp2/src/nghttp.cc

/*
 * nghttp2 - HTTP/2 C Library
 *
 * Copyright (c) 2013 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 "nghttp2_config.h"

#include <sys/types.h>
#include <sys/stat.h>
#include <sys/socket.h>
#include <netdb.h>
#include <unistd.h>
#include <fcntl.h>
#include <netinet/in.h>
#include <netinet/tcp.h>
#include <signal.h>
#include <getopt.h>

#include <cassert>
#include <cstdio>
#include <cerrno>
#include <cstdlib>
#include <cstring>
#include <string>
#include <iostream>
#include <string>
#include <set>
#include <iomanip>
#include <fstream>
#include <map>
#include <vector>
#include <sstream>
#include <tuple>
#include <chrono>

#include <openssl/ssl.h>
#include <openssl/err.h>
#include <openssl/conf.h>

#include <event.h>
#include <event2/event.h>
#include <event2/bufferevent_ssl.h>

#include <nghttp2/nghttp2.h>

#include "http-parser/http_parser.h"

#include "app_helper.h"
#include "HtmlParser.h"
#include "util.h"
#include "libevent_util.h"
#include "base64.h"
#include "http2.h"
#include "nghttp2_gzip.h"

#ifndef O_BINARY
# define O_BINARY (0)
#endif // O_BINARY

namespace nghttp2 {

namespace {
struct Config {
  std::vector<std::pair<std::string, std::string>> headers;
  std::string certfile;
  std::string keyfile;
  std::string datafile;
  nghttp2_option *http2_option;
  size_t output_upper_thres;
  size_t padding;
  ssize_t peer_max_concurrent_streams;
  ssize_t header_table_size;
  int32_t weight;
  int multiply;
  // milliseconds
  int timeout;
  int window_bits;
  int connection_window_bits;
  bool null_out;
  bool remote_name;
  bool verbose;
  bool get_assets;
  bool stat;
  bool upgrade;
  bool continuation;
  bool no_content_length;

  Config()
    : output_upper_thres(1024*1024),
      padding(0),
      peer_max_concurrent_streams(NGHTTP2_INITIAL_MAX_CONCURRENT_STREAMS),
      header_table_size(-1),
      weight(NGHTTP2_DEFAULT_WEIGHT),
      multiply(1),
      timeout(-1),
      window_bits(-1),
      connection_window_bits(-1),
      null_out(false),
      remote_name(false),
      verbose(false),
      get_assets(false),
      stat(false),
      upgrade(false),
      continuation(false),
      no_content_length(false)
  {
    nghttp2_option_new(&http2_option);
    nghttp2_option_set_peer_max_concurrent_streams
      (http2_option,
       peer_max_concurrent_streams);
  }

  ~Config()
  {
    nghttp2_option_del(http2_option);
  }
};
} // namespace

enum StatStage {
  STAT_INITIAL,
  STAT_ON_REQUEST,
  STAT_ON_RESPONSE,
  STAT_ON_COMPLETE
};

namespace {
struct RequestStat {
  std::chrono::steady_clock::time_point on_request_time;
  std::chrono::steady_clock::time_point on_response_time;
  std::chrono::steady_clock::time_point on_complete_time;
  StatStage stage;
  RequestStat():stage(STAT_INITIAL) {}
};
} // namespace

namespace {
std::string strip_fragment(const char *raw_uri)
{
  const char *end;
  for(end = raw_uri; *end && *end != '#'; ++end);
  size_t len = end-raw_uri;
  return std::string(raw_uri, len);
}
} // namespace

namespace {
struct Request;
} // namespace

namespace {
struct Dependency {
  std::vector<std::vector<Request*>> deps;
};
} // namespace

namespace {
struct Request {
  Headers res_nva;
  Headers push_req_nva;
  // URI without fragment
  std::string uri;
  http_parser_url u;
  std::shared_ptr<Dependency> dep;
  nghttp2_priority_spec pri_spec;
  RequestStat stat;
  int64_t data_length;
  int64_t data_offset;
  nghttp2_gzip *inflater;
  HtmlParser *html_parser;
  const nghttp2_data_provider *data_prd;
  int32_t stream_id;
  int status;
  // Recursion level: 0: first entity, 1: entity linked from first entity
  int level;
  // RequestPriority value defined in HtmlParser.h
  int pri;
  bool expect_final_response;

  // For pushed request, |uri| is empty and |u| is zero-cleared.
  Request(const std::string& uri, const http_parser_url &u,
          const nghttp2_data_provider *data_prd, int64_t data_length,
          const nghttp2_priority_spec& pri_spec,
          std::shared_ptr<Dependency> dep, int pri = 0, int level = 0)
    : uri(uri),
      u(u),
      dep(std::move(dep)),
      pri_spec(pri_spec),
      data_length(data_length),
      data_offset(0),
      inflater(nullptr),
      html_parser(nullptr),
      data_prd(data_prd),
      stream_id(-1),
      status(0),
      level(level),
      pri(pri),
      expect_final_response(false)
  {}

  ~Request()
  {
    nghttp2_gzip_inflate_del(inflater);
    delete html_parser;
  }

  void init_inflater()
  {
    int rv;
    rv = nghttp2_gzip_inflate_new(&inflater);
    assert(rv == 0);
  }

  void init_html_parser()
  {
    html_parser = new HtmlParser(uri);
  }

  int update_html_parser(const uint8_t *data, size_t len, int fin)
  {
    if(!html_parser) {
      return 0;
    }
    int rv;
    rv = html_parser->parse_chunk(reinterpret_cast<const char*>(data), len,
                                  fin);
    return rv;
  }

  std::string make_reqpath() const
  {
    std::string path = util::has_uri_field(u, UF_PATH) ?
      util::get_uri_field(uri.c_str(), u, UF_PATH) : "/";
    if(util::has_uri_field(u, UF_QUERY)) {
      path += "?";
      path.append(uri.c_str()+u.field_data[UF_QUERY].off,
                  u.field_data[UF_QUERY].len);
    }
    return path;
  }

  int32_t find_dep_stream_id(int start)
  {
    for(auto i = start; i >= 0; --i) {
      for(auto req : dep->deps[i]) {
        return req->stream_id;
      }
    }
    return -1;
  }

  nghttp2_priority_spec resolve_dep(int32_t pri)
  {
    nghttp2_priority_spec pri_spec;
    int exclusive = 0;
    int32_t stream_id = -1;

    nghttp2_priority_spec_default_init(&pri_spec);

    if(pri == 0) {
      return pri_spec;
    }

    nghttp2_priority_spec_default_init(&pri_spec);

    auto start = std::min(pri, (int)dep->deps.size() - 1);

    for(auto i = start; i >= 0; --i) {
      if(dep->deps[i][0]->pri < pri) {
        stream_id = find_dep_stream_id(i);

        if(i != (int)dep->deps.size() - 1) {
          exclusive = 1;
        }

        break;
      } else if(dep->deps[i][0]->pri == pri) {
        stream_id = find_dep_stream_id(i - 1);

        break;
      }
    }

    if(stream_id == -1) {
      return pri_spec;
    }

    nghttp2_priority_spec_init(&pri_spec, stream_id, NGHTTP2_DEFAULT_WEIGHT,
                               exclusive);

    return pri_spec;
  }

  bool is_ipv6_literal_addr() const
  {
    if(util::has_uri_field(u, UF_HOST)) {
      return memchr(uri.c_str()+u.field_data[UF_HOST].off, ':',
                    u.field_data[UF_HOST].len);
    } else {
      return false;
    }
  }

  bool response_pseudo_header_allowed() const
  {
    return res_nva.empty() || res_nva.back().name.c_str()[0] == ':';
  }

  bool push_request_pseudo_header_allowed() const
  {
    return res_nva.empty() || push_req_nva.back().name.c_str()[0] == ':';
  }

  void record_request_time()
  {
    stat.stage = STAT_ON_REQUEST;
    stat.on_request_time = get_time();
  }

  void record_response_time()
  {
    stat.stage = STAT_ON_RESPONSE;
    stat.on_response_time = get_time();
  }

  void record_complete_time()
  {
    stat.stage = STAT_ON_COMPLETE;
    stat.on_complete_time = get_time();
  }
};
} // namespace

namespace {
struct SessionStat {
  std::chrono::steady_clock::time_point on_handshake_time;
};
} // namespace

namespace {
Config config;
} // namespace

namespace {
size_t populate_settings(nghttp2_settings_entry *iv)
{
  size_t niv = 2;

  iv[0].settings_id = NGHTTP2_SETTINGS_MAX_CONCURRENT_STREAMS;
  iv[0].value = 100;

  iv[1].settings_id = NGHTTP2_SETTINGS_INITIAL_WINDOW_SIZE;
  if(config.window_bits != -1) {
    iv[1].value = (1 << config.window_bits) - 1;
  } else {
    iv[1].value = NGHTTP2_INITIAL_WINDOW_SIZE;
  }

  if(config.header_table_size >= 0) {
    iv[niv].settings_id = NGHTTP2_SETTINGS_HEADER_TABLE_SIZE;
    iv[niv].value = config.header_table_size;
    ++niv;
  }
  return niv;
}
} // namespace

namespace {
void eventcb(bufferevent *bev, short events, void *ptr);
} // namespace

namespace {
extern http_parser_settings htp_hooks;
} // namespace

namespace {
void upgrade_readcb(bufferevent *bev, void *ptr);
} // namespace

namespace {
void readcb(bufferevent *bev, void *ptr);
} // namespace

namespace {
void writecb(bufferevent *bev, void *ptr);
} // namespace

namespace {
struct HttpClient;
} // namespace

namespace {
int submit_request
(HttpClient *client,
 const std::vector<std::pair<std::string, std::string>>& headers,
 Request *req);
} // namespace

namespace {
void settings_timeout_cb(evutil_socket_t fd, short what, void *arg);
} // namespace

enum client_state {
  STATE_IDLE,
  STATE_CONNECTED
};

namespace {
struct HttpClient {
  std::vector<std::unique_ptr<Request>> reqvec;
  // Insert path already added in reqvec to prevent multiple request
  // for 1 resource.
  std::set<std::string> path_cache;
  std::string scheme;
  std::string host;
  std::string hostport;
  // Used for parse the HTTP upgrade response from server
  std::unique_ptr<http_parser> htp;
  SessionStat stat;
  nghttp2_session *session;
  const nghttp2_session_callbacks *callbacks;
  event_base *evbase;
  SSL_CTX *ssl_ctx;
  SSL *ssl;
  bufferevent *bev;
  event *settings_timerev;
  addrinfo *addrs;
  addrinfo *next_addr;
  // The number of completed requests, including failed ones.
  size_t complete;
  // The length of settings_payload
  size_t settings_payloadlen;
  client_state state;
  // The HTTP status code of the response message of HTTP Upgrade.
  unsigned int upgrade_response_status_code;
  // true if the response message of HTTP Upgrade request is fully
  // received. It is not relevant the upgrade succeeds, or not.
  bool upgrade_response_complete;
  // SETTINGS payload sent as token68 in HTTP Upgrade
  uint8_t settings_payload[128];

  HttpClient(const nghttp2_session_callbacks* callbacks,
             event_base *evbase, SSL_CTX *ssl_ctx)
    : session(nullptr),
      callbacks(callbacks),
      evbase(evbase),
      ssl_ctx(ssl_ctx),
      ssl(nullptr),
      bev(nullptr),
      settings_timerev(nullptr),
      addrs(nullptr),
      next_addr(nullptr),
      complete(0),
      settings_payloadlen(0),
      state(STATE_IDLE),
      upgrade_response_status_code(0),
      upgrade_response_complete(false)
  {}

  ~HttpClient()
  {
    disconnect();
    if(addrs) {
      freeaddrinfo(addrs);
      addrs = nullptr;
      next_addr = nullptr;
    }
  }

  bool need_upgrade() const
  {
    return config.upgrade && scheme == "http";
  }

  int resolve_host(const std::string& host, uint16_t port)
  {
    int rv;
    addrinfo hints;
    this->host = host;
    memset(&hints, 0, sizeof(hints));
    hints.ai_family = AF_UNSPEC;
    hints.ai_socktype = SOCK_STREAM;
    hints.ai_protocol = 0;
    hints.ai_flags = AI_ADDRCONFIG;
    rv = getaddrinfo(host.c_str(), util::utos(port).c_str(), &hints, &addrs);
    if(rv != 0) {
      std::cerr << "[ERROR] getaddrinfo() failed: "
                << gai_strerror(rv) << std::endl;
      return -1;
    }
    if(addrs == nullptr) {
      std::cerr << "[ERROR] No address returned" << std::endl;
      return -1;
    }
    next_addr = addrs;
    return 0;
  }

  int initiate_connection()
  {
    int rv = 0;
    if(ssl_ctx) {
      // We are establishing TLS connection.
      ssl = SSL_new(ssl_ctx);
      if(!ssl) {
        std::cerr << "[ERROR] SSL_new() failed: "
                  << ERR_error_string(ERR_get_error(), nullptr) << std::endl;
        return -1;
      }

      // If the user overrode the host header, use that value for the
      // SNI extension
      const char *host_string = nullptr;
      auto i = std::find_if(std::begin(config.headers),
                            std::end(config.headers),
                            [](const std::pair<std::string, std::string>& nv)
                            {
                              return "host" == nv.first;
                            });
      if ( i != std::end(config.headers) ) {
        host_string = (*i).second.c_str();
      } else {
        host_string = host.c_str();
      }

      if (!util::numeric_host(host_string)) {
        SSL_set_tlsext_host_name(ssl, host_string);
      }

      bev = bufferevent_openssl_socket_new(evbase, -1, ssl,
                                           BUFFEREVENT_SSL_CONNECTING,
                                           BEV_OPT_DEFER_CALLBACKS);
    } else {
      bev = bufferevent_socket_new(evbase, -1, BEV_OPT_DEFER_CALLBACKS);
    }
    rv = -1;
    while(next_addr) {
      rv = bufferevent_socket_connect
        (bev, next_addr->ai_addr, next_addr->ai_addrlen);
      next_addr = next_addr->ai_next;
      if(rv == 0) {
        break;
      }
    }
    if(rv != 0) {
      return -1;
    }
    bufferevent_enable(bev, EV_READ);
    if(need_upgrade()) {
      htp = util::make_unique<http_parser>();
      http_parser_init(htp.get(), HTTP_RESPONSE);
      htp->data = this;
      bufferevent_setcb(bev, upgrade_readcb, nullptr, eventcb, this);
    } else {
      bufferevent_setcb(bev, readcb, writecb, eventcb, this);
    }
    if(config.timeout != -1) {
      timeval tv = { config.timeout, 0 };
      bufferevent_set_timeouts(bev, &tv, &tv);
    }
    return 0;
  }

  void disconnect()
  {
    int fd = -1;
    state = STATE_IDLE;
    nghttp2_session_del(session);
    session = nullptr;
    if(ssl) {
      fd = SSL_get_fd(ssl);
      SSL_set_shutdown(ssl, SSL_RECEIVED_SHUTDOWN);
      SSL_shutdown(ssl);
    }
    if(bev) {
      bufferevent_disable(bev, EV_READ | EV_WRITE);
      bufferevent_free(bev);
      bev = nullptr;
    }
    if(settings_timerev) {
      event_free(settings_timerev);
      settings_timerev = nullptr;
    }
    if(ssl) {
      SSL_free(ssl);
      ssl = nullptr;
    }
    if(fd != -1) {
      shutdown(fd, SHUT_WR);
      close(fd);
    }
  }

  int on_upgrade_connect()
  {
    ssize_t rv;
    record_handshake_time();
    assert(!reqvec.empty());
    nghttp2_settings_entry iv[32];
    size_t niv = populate_settings(iv);
    assert(sizeof(settings_payload) >= 8*niv);
    rv = nghttp2_pack_settings_payload(settings_payload,
                                       sizeof(settings_payload), iv, niv);
    if(rv < 0) {
      return -1;
    }
    settings_payloadlen = rv;
    auto token68 = base64::encode(&settings_payload[0],
                                  &settings_payload[settings_payloadlen]);
    util::to_token68(token68);
    std::string req;
    if(reqvec[0]->data_prd) {
      // If the request contains upload data, use OPTIONS * to upgrade
      req = "OPTIONS *";
    } else {
      req = "GET ";
      req += reqvec[0]->make_reqpath();
    }
    req += " HTTP/1.1\r\n"
      "Host: ";
    req += hostport;
    req += "\r\n"
      "Connection: Upgrade, HTTP2-Settings\r\n"
      "Upgrade: " NGHTTP2_CLEARTEXT_PROTO_VERSION_ID "\r\n"
      "HTTP2-Settings: ";
    req += token68;
    req += "\r\n"
      "Accept: */*\r\n"
      "User-Agent: nghttp2/" NGHTTP2_VERSION "\r\n"
      "\r\n";
    bufferevent_write(bev, req.c_str(), req.size());
    if(config.verbose) {
      print_timer();
      std::cout << " HTTP Upgrade request\n"
                << req << std::endl;
    }
    return 0;
  }

  int on_upgrade_read()
  {
    int rv;
    auto input = bufferevent_get_input(bev);

    for(;;) {
      auto inputlen = evbuffer_get_contiguous_space(input);

      if(inputlen == 0) {
        assert(evbuffer_get_length(input) == 0);

        return 0;
      }

      auto mem = evbuffer_pullup(input, inputlen);

      auto nread = http_parser_execute(htp.get(), &htp_hooks,
                                       reinterpret_cast<const char*>(mem),
                                       inputlen);

      if(config.verbose) {
        std::cout.write(reinterpret_cast<const char*>(mem), nread);
      }

      if(evbuffer_drain(input, nread) != 0) {
        return -1;
      }

      auto htperr = HTTP_PARSER_ERRNO(htp.get());

      if(htperr != HPE_OK) {
        std::cerr << "[ERROR] Failed to parse HTTP Upgrade response header: "
                  << "(" << http_errno_name(htperr) << ") "
                  << http_errno_description(htperr) << std::endl;
        return -1;
      }

      if(upgrade_response_complete) {

        if(config.verbose) {
          std::cout << std::endl;
        }

        if(upgrade_response_status_code == 101) {
          if(config.verbose) {
            print_timer();
            std::cout << " HTTP Upgrade success" << std::endl;
          }

          bufferevent_setcb(bev, readcb, writecb, eventcb, this);

          rv = on_connect();

          if(rv != 0) {
            return rv;
          }

          // Read remaining data in the buffer because it is not
          // notified callback anymore.
          rv = on_read();

          if(rv != 0) {
            return rv;
          }

          return 0;
        }

        std::cerr << "[ERROR] HTTP Upgrade failed" << std::endl;

        return -1;
      }
    }
  }

  int on_connect()
  {
    int rv;
    if(!need_upgrade()) {
      record_handshake_time();
    }

    rv = nghttp2_session_client_new2(&session, callbacks, this,
                                     config.http2_option);

    if(rv != 0) {
      return -1;
    }
    if(need_upgrade()) {
      // Adjust stream user-data depending on the existence of upload
      // data
      Request *stream_user_data = nullptr;
      if(!reqvec[0]->data_prd) {
        stream_user_data = reqvec[0].get();
      }
      rv = nghttp2_session_upgrade(session, settings_payload,
                                   settings_payloadlen, stream_user_data);
      if(rv != 0) {
        std::cerr << "[ERROR] nghttp2_session_upgrade() returned error: "
                  << nghttp2_strerror(rv) << std::endl;
        return -1;
      }
      if(stream_user_data) {
        stream_user_data->stream_id = 1;
        on_request(stream_user_data);
      }
    }
    // Send connection header here
    bufferevent_write(bev, NGHTTP2_CLIENT_CONNECTION_PREFACE,
                      NGHTTP2_CLIENT_CONNECTION_PREFACE_LEN);
    // If upgrade succeeds, the SETTINGS value sent with
    // HTTP2-Settings header field has already been submitted to
    // session object.
    if(!need_upgrade()) {
      nghttp2_settings_entry iv[16];
      auto niv = populate_settings(iv);
      rv = nghttp2_submit_settings(session, NGHTTP2_FLAG_NONE, iv, niv);
      if(rv != 0) {
        return -1;
      }
    }
    assert(settings_timerev == nullptr);
    settings_timerev = evtimer_new(evbase, settings_timeout_cb, this);
    // SETTINGS ACK timeout is 10 seconds for now
    timeval settings_timeout = { 10, 0 };
    evtimer_add(settings_timerev, &settings_timeout);

    if(config.connection_window_bits != -1) {
      int32_t wininc = (1 << config.connection_window_bits) - 1
        - NGHTTP2_INITIAL_CONNECTION_WINDOW_SIZE;
      rv = nghttp2_submit_window_update
        (session, NGHTTP2_FLAG_NONE, 0, wininc);
      if(rv != 0) {
        return -1;
      }
    }
    // Adjust first request depending on the existence of the upload
    // data
    for(auto i = std::begin(reqvec)+(need_upgrade() && !reqvec[0]->data_prd);
        i != std::end(reqvec); ++i) {
      if(submit_request(this, config.headers, (*i).get()) != 0) {
        return -1;
      }
    }
    return on_write();
  }

  int on_read()
  {
    int rv;
    auto input = bufferevent_get_input(bev);

    for(;;) {
      auto inputlen = evbuffer_get_contiguous_space(input);

      if(inputlen == 0) {
        assert(evbuffer_get_length(input) == 0);

        return on_write();
      }

      auto mem = evbuffer_pullup(input, inputlen);

      rv = nghttp2_session_mem_recv(session, mem, inputlen);

      if(rv < 0) {
        std::cerr << "[ERROR] nghttp2_session_mem_recv() returned error: "
                  << nghttp2_strerror(rv) << std::endl;
        return -1;
      }

      if(evbuffer_drain(input, rv) != 0) {
        return -1;
      }
    }
  }

  int on_write()
  {
    int rv;
    uint8_t buf[4096];
    auto output = bufferevent_get_output(bev);
    util::EvbufferBuffer evbbuf(output, buf, sizeof(buf));
    for(;;) {
      if(evbuffer_get_length(output) + evbbuf.get_buflen() >
         config.output_upper_thres) {
        break;
      }

      const uint8_t *data;
      auto datalen = nghttp2_session_mem_send(session, &data);

      if(datalen < 0) {
        std::cerr << "[ERROR] nghttp2_session_mem_send() returned error: "
                  << nghttp2_strerror(datalen) << std::endl;
        return -1;
      }
      if(datalen == 0) {
        break;
      }
      rv = evbbuf.add(data, datalen);
      if(rv != 0) {
        std::cerr << "[ERROR] evbuffer_add() failed" << std::endl;
        return -1;
      }
    }
    rv = evbbuf.flush();
    if(rv != 0) {
      std::cerr << "[ERROR] evbuffer_add() failed" << std::endl;
      return -1;
    }
    if(nghttp2_session_want_read(session) == 0 &&
       nghttp2_session_want_write(session) == 0 &&
       evbuffer_get_length(output) == 0) {
      return -1;
    }
    return 0;
  }

  bool all_requests_processed() const
  {
    return complete == reqvec.size();
  }
  void update_hostport()
  {
    if(reqvec.empty()) {
      return;
    }
    scheme = util::get_uri_field(reqvec[0]->uri.c_str(), reqvec[0]->u,
                                 UF_SCHEMA);
    std::stringstream ss;
    if(reqvec[0]->is_ipv6_literal_addr()) {
      ss << "[";
      util::write_uri_field(ss, reqvec[0]->uri.c_str(), reqvec[0]->u, UF_HOST);
      ss << "]";
    } else {
      util::write_uri_field(ss, reqvec[0]->uri.c_str(), reqvec[0]->u, UF_HOST);
    }
    if(util::has_uri_field(reqvec[0]->u, UF_PORT) &&
       reqvec[0]->u.port != util::get_default_port(reqvec[0]->uri.c_str(),
                                                   reqvec[0]->u)) {
      ss << ":" << reqvec[0]->u.port;
    }
    hostport = ss.str();
  }
  bool add_request(const std::string& uri,
                   const nghttp2_data_provider *data_prd,
                   int64_t data_length,
                   const nghttp2_priority_spec& pri_spec,
                   std::shared_ptr<Dependency> dep,
                   int pri = 0, int level = 0)
  {
    http_parser_url u;
    memset(&u, 0, sizeof(u));
    if(http_parser_parse_url(uri.c_str(), uri.size(), 0, &u) != 0) {
      return false;
    }
    if(path_cache.count(uri)) {
      return false;
    }

    if(config.multiply == 1) {
      path_cache.insert(uri);
    }

    reqvec.push_back(util::make_unique<Request>(uri, u, data_prd,
                                                data_length,
                                                pri_spec, std::move(dep),
                                                pri, level));
    return true;
  }
  void record_handshake_time()
  {
    stat.on_handshake_time = get_time();
  }

  void on_request(Request *req)
  {
    req->record_request_time();

    if(req->pri == 0 && req->dep) {
      assert(req->dep->deps.empty());

      req->dep->deps.push_back(std::vector<Request*>{req});

      return;
    }

    if(req->stream_id % 2 == 0) {
      return;
    }

    auto itr = std::begin(req->dep->deps);
    for(; itr != std::end(req->dep->deps); ++itr) {
      if((*itr)[0]->pri == req->pri) {
        (*itr).push_back(req);

        break;
      }

      if((*itr)[0]->pri > req->pri) {
        auto v = std::vector<Request*>{req};
        req->dep->deps.insert(itr, std::move(v));

        break;
      }
    }

    if(itr == std::end(req->dep->deps)) {
      req->dep->deps.push_back(std::vector<Request*>{req});
    }
  }
};
} // namespace

namespace {
int htp_msg_begincb(http_parser *htp)
{
  if(config.verbose) {
    print_timer();
    std::cout << " HTTP Upgrade response" << std::endl;
  }
  return 0;
}
} // namespace

namespace {
int htp_statuscb(http_parser *htp, const char *at, size_t length)
{
  auto client = static_cast<HttpClient*>(htp->data);
  client->upgrade_response_status_code = htp->status_code;
  return 0;
}
} // namespace

namespace {
int htp_msg_completecb(http_parser *htp)
{
  auto client = static_cast<HttpClient*>(htp->data);
  client->upgrade_response_complete = true;
  return 0;
}
} // namespace

namespace {
http_parser_settings htp_hooks = {
  htp_msg_begincb, // http_cb      on_message_begin;
  nullptr, // http_data_cb on_url;
  htp_statuscb, // http_data_cb on_status;
  nullptr, // http_data_cb on_header_field;
  nullptr, // http_data_cb on_header_value;
  nullptr, // http_cb      on_headers_complete;
  nullptr, // http_data_cb on_body;
  htp_msg_completecb // http_cb      on_message_complete;
};
} // namespace

namespace {
int submit_request
(HttpClient *client,
 const std::vector<std::pair<std::string, std::string>>& headers,
 Request *req)
{
  auto path = req->make_reqpath();
  auto scheme = util::get_uri_field(req->uri.c_str(), req->u, UF_SCHEMA);
  auto build_headers = Headers
    {{":method", req->data_prd ? "POST" : "GET"},
     {":path", path},
     {":scheme", scheme},
     {":authority", client->hostport},
     {"accept", "*/*"},
     {"accept-encoding", "gzip, deflate"},
     {"user-agent", "nghttp2/" NGHTTP2_VERSION}};
  if(config.continuation) {
    for(size_t i = 0; i < 6; ++i) {
      build_headers.emplace_back("continuation-test-" + util::utos(i+1),
                                 std::string(4096, '-'));
    }
  }
  auto num_initial_headers = build_headers.size();
  if(!config.no_content_length && req->data_prd) {
    build_headers.emplace_back("content-length", util::utos(req->data_length));
  }
  for(auto& kv : headers) {
    size_t i;
    for(i = 0; i < num_initial_headers; ++i) {
      if(kv.first == build_headers[i].name) {
        build_headers[i].value = kv.second;
        break;
      }
    }
    if(i < num_initial_headers) {
      continue;
    }

    // To test "never index" repr, don't index authorization header
    // field unconditionally.
    auto no_index = kv.first == "authorization";
    build_headers.emplace_back(kv.first, kv.second, no_index);
  }
  std::stable_sort(std::begin(build_headers), std::end(build_headers),
                   http2::name_less);

  auto nva = std::vector<nghttp2_nv>();
  nva.reserve(build_headers.size());

  for(auto& kv : build_headers) {
    nva.push_back(http2::make_nv(kv.name, kv.value, kv.no_index));
  }

  auto stream_id = nghttp2_submit_request(client->session, &req->pri_spec,
                                          nva.data(), nva.size(),
                                          req->data_prd, req);
  if(stream_id < 0) {
    std::cerr << "[ERROR] nghttp2_submit_request() returned error: "
              << nghttp2_strerror(stream_id) << std::endl;
    return -1;
  }

  req->stream_id = stream_id;
  client->on_request(req);

  return 0;
}
} // namespace

namespace {
void update_html_parser(HttpClient *client, Request *req,
                        const uint8_t *data, size_t len, int fin)
{
  if(!req->html_parser) {
    return;
  }
  req->update_html_parser(data, len, fin);

  for(auto& p : req->html_parser->get_links()) {
    auto uri = strip_fragment(p.first.c_str());
    auto pri = p.second;

    http_parser_url u;
    memset(&u, 0, sizeof(u));
    if(http_parser_parse_url(uri.c_str(), uri.size(), 0, &u) == 0 &&
       util::fieldeq(uri.c_str(), u, req->uri.c_str(), req->u, UF_SCHEMA) &&
       util::fieldeq(uri.c_str(), u, req->uri.c_str(), req->u, UF_HOST) &&
       util::porteq(uri.c_str(), u, req->uri.c_str(), req->u)) {
      // No POST data for assets
      auto pri_spec = req->resolve_dep(pri);

      if ( client->add_request(uri, nullptr, 0, pri_spec, req->dep,
                               pri, req->level+1) ) {

        submit_request(client, config.headers,
                       client->reqvec.back().get());
      }
    }
  }
  req->html_parser->clear_links();
}
} // namespace

namespace {
HttpClient* get_session(void *user_data)
{
  return static_cast<HttpClient*>(user_data);
}
} // namespace

namespace {
int on_data_chunk_recv_callback
(nghttp2_session *session, uint8_t flags, int32_t stream_id,
 const uint8_t *data, size_t len, void *user_data)
{
  auto client = get_session(user_data);
  auto req =
    (Request*)nghttp2_session_get_stream_user_data(session, stream_id);

  if(!req) {
    return 0;
  }

  if(config.verbose) {
    verbose_on_data_chunk_recv_callback(session, flags, stream_id, data, len,
                                        user_data);
  }

  if(req->status == 0) {
    nghttp2_submit_rst_stream(session, NGHTTP2_FLAG_NONE,
                              stream_id, NGHTTP2_PROTOCOL_ERROR);
    return 0;
  }

  if(req->inflater) {
    while(len > 0) {
      const size_t MAX_OUTLEN = 4096;
      uint8_t out[MAX_OUTLEN];
      size_t outlen = MAX_OUTLEN;
      size_t tlen = len;
      int rv = nghttp2_gzip_inflate(req->inflater, out, &outlen, data, &tlen);
      if(rv != 0) {
        nghttp2_submit_rst_stream(session, NGHTTP2_FLAG_NONE, stream_id,
                                  NGHTTP2_INTERNAL_ERROR);
        break;
      }
      if(!config.null_out) {
        std::cout.write(reinterpret_cast<const char*>(out), outlen);
      }
      update_html_parser(client, req, out, outlen, 0);
      data += tlen;
      len -= tlen;
    }

    return 0;
  }

  if(!config.null_out) {
    std::cout.write(reinterpret_cast<const char*>(data), len);
  }

  update_html_parser(client, req, data, len, 0);

  return 0;
}
} // namespace

namespace {
void settings_timeout_cb(evutil_socket_t fd, short what, void *arg)
{
  int rv;
  auto client = get_session(arg);
  nghttp2_session_terminate_session(client->session, NGHTTP2_SETTINGS_TIMEOUT);
  rv = client->on_write();
  if(rv != 0) {
    client->disconnect();
  }
}
} // namespace

namespace {
ssize_t select_padding_callback
(nghttp2_session *session, const nghttp2_frame *frame, size_t max_payload,
 void *user_data)
{
  return std::min(max_payload, frame->hd.length + config.padding);
}
} // namespace

namespace {
void check_response_header(nghttp2_session *session, Request* req)
{
  bool gzip = false;

  req->expect_final_response = false;

  for(auto& nv : req->res_nva) {
    if("content-encoding" == nv.name) {
      gzip = util::strieq("gzip", nv.value) ||
        util::strieq("deflate", nv.value);
      continue;
    }
    if(":status" == nv.name) {
      int status;
      if(req->status != 0 ||
         (status = http2::parse_http_status_code(nv.value)) == -1) {

        nghttp2_submit_rst_stream(session, NGHTTP2_FLAG_NONE,
                                  req->stream_id, NGHTTP2_PROTOCOL_ERROR);
        return;
      }

      req->status = status;
    }
  }

  if(req->status == 0) {
    nghttp2_submit_rst_stream(session, NGHTTP2_FLAG_NONE, req->stream_id,
                              NGHTTP2_PROTOCOL_ERROR);
    return;
  }

  if(req->status / 100 == 1) {
    req->expect_final_response = true;
    req->status = 0;
    req->res_nva.clear();
    return;
  }

  if(gzip) {
    if(!req->inflater) {
      req->init_inflater();
    }
  }
  if(config.get_assets && req->level == 0) {
    if(!req->html_parser) {
      req->init_html_parser();
    }
  }
}
} // namespace

namespace {
int on_begin_headers_callback(nghttp2_session *session,
                              const nghttp2_frame *frame,
                              void *user_data)
{
  auto client = get_session(user_data);
  switch(frame->hd.type) {
  case NGHTTP2_PUSH_PROMISE: {
    auto stream_id = frame->push_promise.promised_stream_id;
    http_parser_url u;
    memset(&u, 0, sizeof(u));
    // TODO Set pri and level
    nghttp2_priority_spec pri_spec;

    nghttp2_priority_spec_default_init(&pri_spec);

    auto req = util::make_unique<Request>("", u, nullptr, 0, pri_spec,
                                          nullptr);
    req->stream_id = stream_id;

    nghttp2_session_set_stream_user_data(session, stream_id, req.get());

    client->on_request(req.get());
    client->reqvec.push_back(std::move(req));

    break;
  }
  }
  return 0;
}
} //namespace

namespace {
int on_header_callback(nghttp2_session *session,
                       const nghttp2_frame *frame,
                       const uint8_t *name, size_t namelen,
                       const uint8_t *value, size_t valuelen,
                       uint8_t flags,
                       void *user_data)
{
  if(config.verbose) {
    verbose_on_header_callback(session, frame, name, namelen, value, valuelen,
                               flags, user_data);
  }

  if(!http2::check_nv(name, namelen, value, valuelen)) {
    nghttp2_submit_rst_stream(session, NGHTTP2_FLAG_NONE, frame->hd.stream_id,
                              NGHTTP2_PROTOCOL_ERROR);
    return NGHTTP2_ERR_TEMPORAL_CALLBACK_FAILURE;
  }

  switch(frame->hd.type) {
  case NGHTTP2_HEADERS: {
    auto req = (Request*)nghttp2_session_get_stream_user_data
      (session, frame->hd.stream_id);

    if(!req) {
      break;
    }

    if(frame->headers.cat != NGHTTP2_HCAT_RESPONSE &&
       frame->headers.cat != NGHTTP2_HCAT_PUSH_RESPONSE &&
       (frame->headers.cat != NGHTTP2_HCAT_HEADERS ||
        !req->expect_final_response)) {
      break;
    }

    if(namelen > 0 && name[0] == ':') {
      if(!req->response_pseudo_header_allowed() ||
         !http2::check_http2_response_pseudo_header(name, namelen)) {
        nghttp2_submit_rst_stream(session, NGHTTP2_FLAG_NONE,
                                  frame->hd.stream_id,
                                  NGHTTP2_PROTOCOL_ERROR);
        return NGHTTP2_ERR_TEMPORAL_CALLBACK_FAILURE;
      }
    }

    http2::add_header(req->res_nva, name, namelen, value, valuelen,
                      flags & NGHTTP2_NV_FLAG_NO_INDEX);
    break;
  }
  case NGHTTP2_PUSH_PROMISE: {
    auto req = (Request*)nghttp2_session_get_stream_user_data
      (session, frame->push_promise.promised_stream_id);

    if(!req) {
      break;
    }

    if(namelen > 0 && name[0] == ':') {
      if(!req->push_request_pseudo_header_allowed() ||
         !http2::check_http2_request_pseudo_header(name, namelen)) {
        nghttp2_submit_rst_stream(session, NGHTTP2_FLAG_NONE,
                                  frame->push_promise.promised_stream_id,
                                  NGHTTP2_PROTOCOL_ERROR);
        break;
      }
    }

    http2::add_header(req->push_req_nva, name, namelen, value, valuelen,
                      flags & NGHTTP2_NV_FLAG_NO_INDEX);
    break;
  }
  }
  return 0;
}
} // namespace

namespace {
int on_frame_recv_callback2
(nghttp2_session *session, const nghttp2_frame *frame, void *user_data)
{
  int rv = 0;

  if(config.verbose) {
    verbose_on_frame_recv_callback(session, frame, user_data);
  }

  auto client = get_session(user_data);
  switch(frame->hd.type) {
  case NGHTTP2_HEADERS: {
    auto req = (Request*)nghttp2_session_get_stream_user_data
      (session, frame->hd.stream_id);
    // If this is the HTTP Upgrade with OPTIONS method to avoid POST,
    // req is nullptr.
    if(!req) {
      break;
    }

    if(frame->headers.cat == NGHTTP2_HCAT_RESPONSE ||
       frame->headers.cat == NGHTTP2_HCAT_PUSH_RESPONSE) {
      req->record_response_time();
      check_response_header(session, req);

      break;
    }

    if(frame->headers.cat == NGHTTP2_HCAT_HEADERS) {
      if(req->expect_final_response) {
        check_response_header(session, req);
      } else {
        nghttp2_submit_rst_stream(session, NGHTTP2_FLAG_NONE,
                                  frame->hd.stream_id, NGHTTP2_PROTOCOL_ERROR);
        break;
      }
    }

    if(req->status == 0 && (frame->hd.flags & NGHTTP2_FLAG_END_STREAM)) {
      nghttp2_submit_rst_stream(session, NGHTTP2_FLAG_NONE,
                                frame->hd.stream_id, NGHTTP2_PROTOCOL_ERROR);
      break;
    }

    break;
  }
  case NGHTTP2_SETTINGS:
    if((frame->hd.flags & NGHTTP2_FLAG_ACK) == 0) {
      break;
    }
    if(client->settings_timerev) {
      evtimer_del(client->settings_timerev);
      event_free(client->settings_timerev);
      client->settings_timerev = nullptr;
    }
    break;
  case NGHTTP2_PUSH_PROMISE: {
    auto req = (Request*)nghttp2_session_get_stream_user_data
      (session, frame->push_promise.promised_stream_id);
    if(!req) {
      break;
    }
    std::string scheme, authority, method, path;
    for(auto& nv : req->push_req_nva) {
      if(nv.name == ":scheme") {
        scheme = nv.value;
        continue;
      }
      if(nv.name == ":authority" || nv.name == "host") {
        authority = nv.value;
        continue;
      }
      if(nv.name == ":method") {
        method = nv.value;
        continue;
      }
      if(nv.name == ":path") {
        path = nv.value;
        continue;
      }
    }
    if(scheme.empty() || authority.empty() || method.empty() || path.empty() ||
       path[0] != '/') {
      nghttp2_submit_rst_stream(session, NGHTTP2_FLAG_NONE,
                                frame->push_promise.promised_stream_id,
                                NGHTTP2_PROTOCOL_ERROR);
      break;
    }
    std::string uri = scheme;
    uri += "://";
    uri += authority;
    uri += path;
    http_parser_url u;
    memset(&u, 0, sizeof(u));
    if(http_parser_parse_url(uri.c_str(), uri.size(), 0, &u) != 0) {
      nghttp2_submit_rst_stream(session, NGHTTP2_FLAG_NONE,
                                frame->push_promise.promised_stream_id,
                                NGHTTP2_PROTOCOL_ERROR);
      break;
    }
    req->uri = uri;
    req->u = u;
    break;
  }
  }
  return rv;
}
} // namespace

namespace {
int on_stream_close_callback
(nghttp2_session *session, int32_t stream_id, uint32_t error_code,
 void *user_data)
{
  auto client = get_session(user_data);
  auto req =
    (Request*)nghttp2_session_get_stream_user_data(session, stream_id);

  if(!req) {
    return 0;
  }

  update_html_parser(client, req, nullptr, 0, 1);
  req->record_complete_time();
  ++client->complete;

  if(client->all_requests_processed()) {
    nghttp2_session_terminate_session(session, NGHTTP2_NO_ERROR);
  }

  return 0;
}
} // namespace

namespace {
void print_stats(const HttpClient& client)
{
  std::cout << "***** Statistics *****" << std::endl;
  int i = 0;
  for(auto& req : client.reqvec) {
    std::cout << "#" << ++i << ": " << req->uri << std::endl;
    std::cout << "    Status: " << req->status << std::endl;
    std::cout << "    Delta (ms) from handshake(HEADERS):"
              << std::endl;
    if(req->stat.stage >= STAT_ON_RESPONSE) {
      std::cout << "        response HEADERS: "
                << time_delta(req->stat.on_response_time,
                              client.stat.on_handshake_time).count()
                << "("
                << time_delta(req->stat.on_response_time,
                              req->stat.on_request_time).count()
                << ")"
                << std::endl;
    }
    if(req->stat.stage >= STAT_ON_COMPLETE) {
      std::cout << "        Completed: "
                << time_delta(req->stat.on_complete_time,
                              client.stat.on_handshake_time).count()
                << "("
                << time_delta(req->stat.on_complete_time,
                              req->stat.on_request_time).count()
                << ")"
                << std::endl;
    }
    std::cout << std::endl;
  }
}
} // namespace

namespace {
void print_protocol_nego_error()
{
  std::cerr << "[ERROR] HTTP/2 protocol was not selected."
            << " (nghttp2 expects " << NGHTTP2_PROTO_VERSION_ID << ")"
            << std::endl;
}
} // namespace

namespace {
int client_select_next_proto_cb(SSL* ssl,
                                unsigned char **out, unsigned char *outlen,
                                const unsigned char *in, unsigned int inlen,
                                void *arg)
{
  if(config.verbose) {
    print_timer();
    std::cout << "[NPN] server offers:" << std::endl;
  }
  for(unsigned int i = 0; i < inlen; i += in[i]+1) {
    if(config.verbose) {
      std::cout << "          * ";
      std::cout.write(reinterpret_cast<const char*>(&in[i+1]), in[i]);
      std::cout << std::endl;
    }
  }
  if(nghttp2_select_next_protocol(out, outlen, in, inlen) <= 0) {
    print_protocol_nego_error();
    return SSL_TLSEXT_ERR_NOACK;
  }
  return SSL_TLSEXT_ERR_OK;
}
} // namespace

namespace {
void upgrade_readcb(bufferevent *bev, void *ptr)
{
  int rv;
  auto client = static_cast<HttpClient*>(ptr);
  rv = client->on_upgrade_read();
  if(rv != 0) {
    client->disconnect();
  }
}
} // namespace

namespace {
void readcb(bufferevent *bev, void *ptr)
{
  int rv;
  auto client = static_cast<HttpClient*>(ptr);
  rv = client->on_read();
  if(rv != 0) {
    client->disconnect();
  }
}
} // namespace

namespace {
void writecb(bufferevent *bev, void *ptr)
{
  if(evbuffer_get_length(bufferevent_get_output(bev)) > 0) {
    return;
  }
  int rv;
  auto client = static_cast<HttpClient*>(ptr);
  rv = client->on_write();
  if(rv != 0) {
    client->disconnect();
  }
}
} // namespace

namespace {
void eventcb(bufferevent *bev, short events, void *ptr)
{
  int rv;
  auto client = static_cast<HttpClient*>(ptr);
  if(events & BEV_EVENT_CONNECTED) {
    client->state = STATE_CONNECTED;
    int fd = bufferevent_getfd(bev);
    int val = 1;
    if(setsockopt(fd, IPPROTO_TCP, TCP_NODELAY,
                  reinterpret_cast<char *>(&val), sizeof(val)) == -1) {
      std::cerr << "[ERROR] Setting option TCP_NODELAY failed: errno="
                << errno << std::endl;
    }
    if(client->need_upgrade()) {
      rv = client->on_upgrade_connect();
    } else {
      if(client->ssl) {
        // Check NPN or ALPN result
        const unsigned char *next_proto = nullptr;
        unsigned int next_proto_len;
        SSL_get0_next_proto_negotiated(client->ssl,
                                       &next_proto, &next_proto_len);
        for(int i = 0; i < 2; ++i) {
          if(next_proto) {
            if(config.verbose) {
              std::cout << "The negotiated protocol: ";
              std::cout.write(reinterpret_cast<const char*>(next_proto),
                              next_proto_len);
              std::cout << std::endl;
            }
            if(NGHTTP2_PROTO_VERSION_ID_LEN != next_proto_len ||
               memcmp(NGHTTP2_PROTO_VERSION_ID, next_proto,
                      NGHTTP2_PROTO_VERSION_ID_LEN) != 0) {
              next_proto = nullptr;
            }
            break;
          }
#if OPENSSL_VERSION_NUMBER >= 0x10002000L
          SSL_get0_alpn_selected(client->ssl, &next_proto, &next_proto_len);
#else // OPENSSL_VERSION_NUMBER < 0x10002000L
          break;
#endif // OPENSSL_VERSION_NUMBER < 0x10002000L
        }
        if(!next_proto) {
          print_protocol_nego_error();
          client->disconnect();
          return;
        }
      }
      rv = client->on_connect();
    }
    if(rv != 0) {
      client->disconnect();
      return;
    }
    return;
  }
  if(events & BEV_EVENT_EOF) {
    std::cerr << "EOF" << std::endl;
    auto state = client->state;
    client->disconnect();
    if(state == STATE_IDLE) {
      if(client->initiate_connection() == 0) {
        std::cerr << "Trying next address" << std::endl;
      }
    }
    return;
  }
  if(events & (BEV_EVENT_ERROR | BEV_EVENT_TIMEOUT)) {
    if(events & BEV_EVENT_ERROR) {
      if(client->state == STATE_IDLE) {
        std::cerr << "[ERROR] Could not connect to the host" << std::endl;
      } else {
        std::cerr << "[ERROR] Network error" << std::endl;
      }
    } else {
      std::cerr << "[ERROR] Timeout" << std::endl;
    }
    auto state = client->state;
    client->disconnect();
    if(state == STATE_IDLE) {
      if(client->initiate_connection() == 0) {
        std::cerr << "Trying next address" << std::endl;
      }
    }
    return;
  }
}
} // namespace

namespace {
int communicate(const std::string& scheme, const std::string& host,
                uint16_t port,
                std::vector<std::tuple<std::string,
                                       nghttp2_data_provider*,
                                       int64_t>> requests,
                const nghttp2_session_callbacks *callbacks)
{
  int result = 0;
  auto evbase = event_base_new();
  SSL_CTX *ssl_ctx = nullptr;
  if(scheme == "https") {
    ssl_ctx = SSL_CTX_new(SSLv23_client_method());
    if(!ssl_ctx) {
      std::cerr << "[ERROR] Failed to create SSL_CTX: "
                << ERR_error_string(ERR_get_error(), nullptr) << std::endl;
      result = -1;
      goto fin;
    }
    SSL_CTX_set_options(ssl_ctx,
                        SSL_OP_ALL | SSL_OP_NO_SSLv2 | SSL_OP_NO_COMPRESSION |
                        SSL_OP_NO_SESSION_RESUMPTION_ON_RENEGOTIATION);
    SSL_CTX_set_mode(ssl_ctx, SSL_MODE_ENABLE_PARTIAL_WRITE);
    SSL_CTX_set_mode(ssl_ctx, SSL_MODE_AUTO_RETRY);
    SSL_CTX_set_mode(ssl_ctx, SSL_MODE_RELEASE_BUFFERS);
    if(!config.keyfile.empty()) {
      if(SSL_CTX_use_PrivateKey_file(ssl_ctx, config.keyfile.c_str(),
                                     SSL_FILETYPE_PEM) != 1) {
        std::cerr << "[ERROR] "
                  << ERR_error_string(ERR_get_error(), nullptr) << std::endl;
        result = -1;
        goto fin;
      }
    }
    if(!config.certfile.empty()) {
      if(SSL_CTX_use_certificate_chain_file(ssl_ctx,
                                            config.certfile.c_str()) != 1) {
        std::cerr << "[ERROR] "
                  << ERR_error_string(ERR_get_error(), nullptr) << std::endl;
        result = -1;
        goto fin;
      }
    }
    SSL_CTX_set_next_proto_select_cb(ssl_ctx,
                                     client_select_next_proto_cb, nullptr);

#if OPENSSL_VERSION_NUMBER >= 0x10002000L
    unsigned char proto_list[255];
    proto_list[0] = NGHTTP2_PROTO_VERSION_ID_LEN;
    memcpy(&proto_list[1], NGHTTP2_PROTO_VERSION_ID,
           NGHTTP2_PROTO_VERSION_ID_LEN);
    SSL_CTX_set_alpn_protos(ssl_ctx, proto_list, proto_list[0] + 1);
#endif // OPENSSL_VERSION_NUMBER >= 0x10002000L
  }
  {
    HttpClient client{callbacks, evbase, ssl_ctx};

    nghttp2_priority_spec pri_spec;

    if(config.weight != NGHTTP2_DEFAULT_WEIGHT) {
      nghttp2_priority_spec_init(&pri_spec, 0, config.weight, 0);
    } else {
      nghttp2_priority_spec_default_init(&pri_spec);
    }

    for(auto req : requests) {
      for(int i = 0; i < config.multiply; ++i) {
        auto dep = std::make_shared<Dependency>();
        client.add_request(std::get<0>(req), std::get<1>(req),
                           std::get<2>(req), pri_spec, std::move(dep));
      }
    }
    client.update_hostport();
    if(client.resolve_host(host, port) != 0) {
      goto fin;
    }
    if(client.initiate_connection() != 0) {
      goto fin;
    }
    event_base_loop(evbase, 0);

    if(!client.all_requests_processed()) {
      std::cerr << "Some requests were not processed. total="
                << client.reqvec.size()
                << ", processed=" << client.complete << std::endl;
    }
    if(config.stat) {
      print_stats(client);
    }
  }
 fin:
  if(ssl_ctx) {
    SSL_CTX_free(ssl_ctx);
  }
  if(evbase) {
    event_base_free(evbase);
  }
  return result;
}
} // namespace

namespace {
ssize_t file_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)
{
  auto req = (Request*)nghttp2_session_get_stream_user_data
    (session, stream_id);
  assert(req);
  int fd = source->fd;
  ssize_t nread;

  while((nread = pread(fd, buf, length, req->data_offset)) == -1 &&
        errno == EINTR);

  if(nread == -1) {
    return NGHTTP2_ERR_TEMPORAL_CALLBACK_FAILURE;
  }

  if(nread == 0) {
    *data_flags |= NGHTTP2_DATA_FLAG_EOF;
  } else {
    req->data_offset += nread;
  }

  return nread;
}
} // namespace

namespace {
int run(char **uris, int n)
{
  nghttp2_session_callbacks *callbacks;

  nghttp2_session_callbacks_new(&callbacks);
  auto cbsdel = util::defer(callbacks, nghttp2_session_callbacks_del);

  nghttp2_session_callbacks_set_on_stream_close_callback
    (callbacks, on_stream_close_callback);

  nghttp2_session_callbacks_set_on_frame_recv_callback
    (callbacks, on_frame_recv_callback2);

  if(config.verbose) {
    nghttp2_session_callbacks_set_on_frame_send_callback
      (callbacks, verbose_on_frame_send_callback);

    nghttp2_session_callbacks_set_on_invalid_frame_recv_callback
      (callbacks, verbose_on_invalid_frame_recv_callback);
  }

  nghttp2_session_callbacks_set_on_data_chunk_recv_callback
    (callbacks, on_data_chunk_recv_callback);

  nghttp2_session_callbacks_set_on_begin_headers_callback
    (callbacks, on_begin_headers_callback);

  nghttp2_session_callbacks_set_on_header_callback
    (callbacks, on_header_callback);

  if(config.padding) {
    nghttp2_session_callbacks_set_select_padding_callback
      (callbacks, select_padding_callback);
  }

  std::string prev_scheme;
  std::string prev_host;
  uint16_t prev_port = 0;
  int failures = 0;
  int data_fd = -1;
  nghttp2_data_provider data_prd;
  struct stat data_stat;

  if(!config.datafile.empty()) {
    data_fd = open(config.datafile.c_str(), O_RDONLY | O_BINARY);
    if(data_fd == -1) {
      std::cerr << "[ERROR] Could not open file "
                << config.datafile << std::endl;
      return 1;
    }
    if(fstat(data_fd, &data_stat) == -1) {
      close(data_fd);
      std::cerr << "[ERROR] Could not stat file "
                << config.datafile << std::endl;
      return 1;
    }
    data_prd.source.fd = data_fd;
    data_prd.read_callback = file_read_callback;
  }
  std::vector<std::tuple<std::string, nghttp2_data_provider*, int64_t>>
    requests;
  for(int i = 0; i < n; ++i) {
    http_parser_url u;
    memset(&u, 0, sizeof(u));
    auto uri = strip_fragment(uris[i]);
    if(http_parser_parse_url(uri.c_str(), uri.size(), 0, &u) == 0 &&
       util::has_uri_field(u, UF_SCHEMA)) {
      uint16_t port = util::has_uri_field(u, UF_PORT) ?
        u.port : util::get_default_port(uri.c_str(), u);
      if(!util::fieldeq(uri.c_str(), u, UF_SCHEMA, prev_scheme.c_str()) ||
         !util::fieldeq(uri.c_str(), u, UF_HOST, prev_host.c_str()) ||
         port != prev_port) {
        if(!requests.empty()) {
          if (communicate(prev_scheme, prev_host, prev_port,
                          std::move(requests), callbacks) != 0) {
            ++failures;
          }
          requests.clear();
        }
        prev_scheme = util::get_uri_field(uri.c_str(), u, UF_SCHEMA);
        prev_host = util::get_uri_field(uri.c_str(), u, UF_HOST);
        prev_port = port;
      }
      requests.emplace_back(uri, data_fd == -1 ? nullptr : &data_prd,
                            data_stat.st_size);
    }
  }
  if(!requests.empty()) {
    if (communicate(prev_scheme, prev_host, prev_port, std::move(requests),
                    callbacks) != 0) {
      ++failures;
    }
  }
  return failures;
}
} // namespace

namespace {
void print_version(std::ostream& out)
{
  out << "nghttp nghttp2/" NGHTTP2_VERSION << std::endl;
}
} // namespace

namespace {
void print_usage(std::ostream& out)
{
  out << R"(Usage: nghttp [OPTIONS]... <URI>...
HTTP/2 experimental client)" << std::endl;
}
} // namespace

namespace {
void print_help(std::ostream& out)
{
  print_usage(out);
  out << R"(
  <URI>              Specify URI to access.
Options:
  -v, --verbose      Print  debug information  such  as reception  and
                     transmission of frames and name/value pairs.
  -n, --null-out     Discard downloaded data.
  -O, --remote-name  Save download data in the current directory.  The
                     filename is dereived from  URI.  If URI ends with
                     '/',  'index.html' is  used as  a filename.   Not
                     implemented yet.
  -t, --timeout=<N>  Timeout each request after <N> seconds.
  -w, --window-bits=<N>
                     Sets  the stream  level  initial  window size  to
                     2**<N>-1.
  -W, --connection-window-bits=<N>
                     Sets the connection level  initial window size to
                     2**<N>-1.
  -a, --get-assets   Download assets  such as stylesheets,  images and
                     script files linked from the downloaded resource.
                     Only links  whose origins  are the same  with the
                     linking  resource  will  be  downloaded.   nghttp
                     prioritizes  resources  using  HTTP/2  dependency
                     based priority.  The priority order, from highest
                     to lowest,  is html  itself, css,  javascript and
                     images.
  -s, --stat         Print statistics.
  -H, --header=<HEADER>
                     Add   a  header   to   the  requests.    Example:
                     -H':method: PUT'
  --cert=<CERT>      Use the  specified client certificate  file.  The
                     file must be in PEM format.
  --key=<KEY>        Use the  client private key file.   The file must
                     be in PEM format.
  -d, --data=<FILE>  Post FILE to  server. If '-' is  given, data will
                     be read from stdin.
  -m, --multiply=<N> Request each URI <N> times.  By default, same URI
                     is not requested twice.   This option disables it
                     too.
  -u, --upgrade      Perform HTTP Upgrade for  HTTP/2.  This option is
                     ignored if the request  URI has https scheme.  If
                     -d is used, the HTTP upgrade request is performed
                     with OPTIONS method.
  -p, --weight=<WEIGHT>
                     Sets  priority  group  weight.  The  valid  value
                     range is [)"
      << NGHTTP2_MIN_WEIGHT << ", " << NGHTTP2_MAX_WEIGHT << R"(], inclusive.
                     Default: )"
      << NGHTTP2_DEFAULT_WEIGHT << R"(
  -M, --peer-max-concurrent-streams=<N>
                     Use <N>  as SETTINGS_MAX_CONCURRENT_STREAMS value
                     of  remote  endpoint  as  if it  is  received  in
                     SETTINGS frame.   The default is large  enough as
                     it is seen as unlimited.
  -c, --header-table-size=<N>
                     Specify decoder header table size.
  -b, --padding=<N>  Add  at most  <N>  bytes to  a  frame payload  as
                     padding.  Specify 0 to disable padding.
  --color            Force colored log output.
  --continuation     Send large header to test CONTINUATION.
  --no-content-length
                     Don't send content-length header field.
  --version          Display version information and exit.
  -h, --help         Display this help and exit.)"
      << std::endl;
}
} // namespace

int main(int argc, char **argv)
{
  bool color = false;
  while(1) {
    static int flag = 0;
    static option long_options[] = {
      {"verbose", no_argument, nullptr, 'v'},
      {"null-out", no_argument, nullptr, 'n'},
      {"remote-name", no_argument, nullptr, 'O'},
      {"timeout", required_argument, nullptr, 't'},
      {"window-bits", required_argument, nullptr, 'w'},
      {"connection-window-bits", required_argument, nullptr, 'W'},
      {"get-assets", no_argument, nullptr, 'a'},
      {"stat", no_argument, nullptr, 's'},
      {"help", no_argument, nullptr, 'h'},
      {"header", required_argument, nullptr, 'H'},
      {"data", required_argument, nullptr, 'd'},
      {"multiply", required_argument, nullptr, 'm'},
      {"upgrade", no_argument, nullptr, 'u'},
      {"weight", required_argument, nullptr, 'p'},
      {"peer-max-concurrent-streams", required_argument, nullptr, 'M'},
      {"header-table-size", required_argument, nullptr, 'c'},
      {"padding", required_argument, nullptr, 'b'},
      {"cert", required_argument, &flag, 1},
      {"key", required_argument, &flag, 2},
      {"color", no_argument, &flag, 3},
      {"continuation", no_argument, &flag, 4},
      {"version", no_argument, &flag, 5},
      {"no-content-length", no_argument, &flag, 6},
      {nullptr, 0, nullptr, 0 }
    };
    int option_index = 0;
    int c = getopt_long(argc, argv, "M:Oab:c:d:gm:np:hH:vst:uw:W:",
                        long_options, &option_index);
    char *end;
    if(c == -1) {
      break;
    }
    switch(c) {
    case 'M':
      // peer-max-concurrent-streams option
      config.peer_max_concurrent_streams = strtoul(optarg, nullptr, 10);
      break;
    case 'O':
      config.remote_name = true;
      break;
    case 'h':
      print_help(std::cout);
      exit(EXIT_SUCCESS);
    case 'b':
      config.padding = strtol(optarg, nullptr, 10);
      break;
    case 'n':
      config.null_out = true;
      break;
    case 'p': {
      errno = 0;
      auto n = strtoul(optarg, nullptr, 10);
      if(errno == 0 && NGHTTP2_MIN_WEIGHT <= n && n <= NGHTTP2_MAX_WEIGHT) {
        config.weight = n;
      } else {
        std::cerr << "-p: specify the integer in the range ["
                  << NGHTTP2_MIN_WEIGHT << ", "
                  << NGHTTP2_MAX_WEIGHT << "], inclusive"
                  << std::endl;
        exit(EXIT_FAILURE);
      }
      break;
    }
    case 'v':
      config.verbose = true;
      break;
    case 't':
      config.timeout = atoi(optarg) * 1000;
      break;
    case 'u':
      config.upgrade = true;
      break;
    case 'w':
    case 'W': {
      errno = 0;
      char *endptr = nullptr;
      unsigned long int n = strtoul(optarg, &endptr, 10);
      if(errno == 0 && *endptr == '\0' && n < 31) {
        if(c == 'w') {
          config.window_bits = n;
        } else {
          config.connection_window_bits = n;
        }
      } else {
        std::cerr << "-" << static_cast<char>(c)
                  << ": specify the integer in the range [0, 30], inclusive"
                  << std::endl;
        exit(EXIT_FAILURE);
      }
      break;
    }
    case 'H': {
      char *header = optarg;
      // Skip first possible ':' in the header name
      char *value = strchr( optarg + 1, ':' );
      if ( ! value || (header[0] == ':' && header + 1 == value)) {
        std::cerr << "-H: invalid header: " << optarg
                  << std::endl;
        exit(EXIT_FAILURE);
      }
      *value = 0;
      value++;
      while( isspace( *value ) ) { value++; }
      if ( *value == 0 ) {
        // This could also be a valid case for suppressing a header
        // similar to curl
        std::cerr << "-H: invalid header - value missing: " << optarg
                  << std::endl;
        exit(EXIT_FAILURE);
      }
      // Note that there is no processing currently to handle multiple
      // message-header fields with the same field name
      config.headers.emplace_back(header, value);
      util::inp_strlower(config.headers.back().first);
      break;
    }
    case 'a':
#ifdef HAVE_LIBXML2
      config.get_assets = true;
#else // !HAVE_LIBXML2
      std::cerr << "[WARNING]: -a, --get-assets option cannot be used because\n"
                << "the binary was not compiled with libxml2."
                << std::endl;
#endif // !HAVE_LIBXML2
      break;
    case 's':
      config.stat = true;
      break;
    case 'd':
      config.datafile = strcmp("-", optarg) == 0 ? "/dev/stdin" : optarg;
      break;
    case 'm':
      config.multiply = strtoul(optarg, nullptr, 10);
      break;
    case 'c':
      errno = 0;
      config.header_table_size = strtol(optarg, &end, 10);
      if(errno == ERANGE || *end != '\0') {
        std::cerr << "-c: Bad option value: " << optarg << std::endl;
        exit(EXIT_FAILURE);
      }
      break;
    case '?':
      util::show_candidates(argv[optind - 1], long_options);
      exit(EXIT_FAILURE);
    case 0:
      switch(flag) {
      case 1:
        // cert option
        config.certfile = optarg;
        break;
      case 2:
        // key option
        config.keyfile = optarg;
        break;
      case 3:
        // color option
        color = true;
        break;
      case 4:
        // continuation option
        config.continuation = true;
        break;
      case 5:
        // version option
        print_version(std::cout);
        exit(EXIT_SUCCESS);
      case 6:
        // no-content-length option
        config.no_content_length = true;
        break;
      }
      break;
    default:
      break;
    }
  }

  set_color_output(color || isatty(fileno(stdout)));

  nghttp2_option_set_peer_max_concurrent_streams
    (config.http2_option, config.peer_max_concurrent_streams);

  struct sigaction act;
  memset(&act, 0, sizeof(struct sigaction));
  act.sa_handler = SIG_IGN;
  sigaction(SIGPIPE, &act, nullptr);
  OPENSSL_config(nullptr);
  OpenSSL_add_all_algorithms();
  SSL_load_error_strings();
  SSL_library_init();
  reset_timer();
  return run(argv+optind, argc-optind);
}

} // namespace nghttp2

int main(int argc, char **argv)
{
  return nghttp2::main(argc, argv);
}