nghttp2/src/h2load.cc

/*
 * nghttp2 - HTTP/2 C Library
 *
 * Copyright (c) 2014 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 "h2load.h"

#include <getopt.h>
#include <signal.h>
#ifdef HAVE_NETINET_IN_H
#include <netinet/in.h>
#endif // HAVE_NETINET_IN_H
#include <netinet/tcp.h>
#include <sys/stat.h>
#ifdef HAVE_FCNTL_H
#include <fcntl.h>
#endif // HAVE_FCNTL_H

#include <cstdio>
#include <cassert>
#include <cstdlib>
#include <iostream>
#include <iomanip>
#include <fstream>
#include <chrono>
#include <thread>
#include <future>

#ifdef HAVE_SPDYLAY
#include <spdylay/spdylay.h>
#endif // HAVE_SPDYLAY

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

#include "http-parser/http_parser.h"

#include "h2load_http2_session.h"
#ifdef HAVE_SPDYLAY
#include "h2load_spdy_session.h"
#endif // HAVE_SPDYLAY
#include "ssl.h"
#include "http2.h"
#include "util.h"
#include "template.h"

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

using namespace nghttp2;

namespace h2load {

Config::Config()
    : data_length(-1), addrs(nullptr), nreqs(1), nclients(1), nthreads(1),
      max_concurrent_streams(-1), window_bits(30), connection_window_bits(30),
      rate(0), nconns(0), conn_active_timeout(0), conn_inactivity_timeout(0),
      no_tls_proto(PROTO_HTTP2), data_fd(-1), port(0), default_port(0),
      verbose(false), timing_script(false) {}

Config::~Config() {
  freeaddrinfo(addrs);

  if (data_fd != -1) {
    close(data_fd);
  }
}

bool Config::is_rate_mode() const { return (this->rate != 0); }
bool Config::has_base_uri() const { return (!this->base_uri.empty()); }
Config config;

namespace {
void debug(const char *format, ...) {
  if (config.verbose) {
    fprintf(stderr, "[DEBUG] ");
    va_list ap;
    va_start(ap, format);
    vfprintf(stderr, format, ap);
    va_end(ap);
  }
}
} // namespace

namespace {
void debug_nextproto_error() {
#ifdef HAVE_SPDYLAY
  debug("no supported protocol was negotiated, expected: %s, "
        "spdy/2, spdy/3, spdy/3.1\n",
        NGHTTP2_PROTO_VERSION_ID);
#else  // !HAVE_SPDYLAY
  debug("no supported protocol was negotiated, expected: %s\n",
        NGHTTP2_PROTO_VERSION_ID);
#endif // !HAVE_SPDYLAY
}
} // namespace

RequestStat::RequestStat() : data_offset(0), completed(false) {}

Stats::Stats(size_t req_todo)
    : req_todo(0), req_started(0), req_done(0), req_success(0),
      req_status_success(0), req_failed(0), req_error(0), req_timedout(0),
      bytes_total(0), bytes_head(0), bytes_body(0), status(),
      req_stats(req_todo) {}

Stream::Stream() : status_success(-1) {}

namespace {
void writecb(struct ev_loop *loop, ev_io *w, int revents) {
  auto client = static_cast<Client *>(w->data);
  client->restart_timeout();
  auto rv = client->do_write();
  if (rv == Client::ERR_CONNECT_FAIL) {
    client->disconnect();
    rv = client->connect();
    if (rv != 0) {
      client->fail();
      return;
    }
    return;
  }
  if (rv != 0) {
    client->fail();
  }
}
} // namespace

namespace {
void readcb(struct ev_loop *loop, ev_io *w, int revents) {
  auto client = static_cast<Client *>(w->data);
  client->restart_timeout();
  if (client->do_read() != 0) {
    client->fail();
    return;
  }
  writecb(loop, &client->wev, revents);
  // client->disconnect() and client->fail() may be called
}
} // namespace

namespace {
// Called every second when rate mode is being used
void second_timeout_w_cb(struct ev_loop *loop, ev_timer *w, int revents) {
  auto worker = static_cast<Worker *>(w->data);
  auto nclients_per_second = worker->rate;
  auto conns_remaining = worker->nclients - worker->nconns_made;
  auto nclients = std::min(nclients_per_second, conns_remaining);

  for (size_t i = 0; i < nclients; ++i) {
    auto req_todo = worker->config->max_concurrent_streams;
    worker->clients.push_back(make_unique<Client>(worker, req_todo));
    auto &client = worker->clients.back();
    if (client->connect() != 0) {
      std::cerr << "client could not connect to host" << std::endl;
      client->fail();
    }
    ++worker->nconns_made;
  }
  if (worker->nconns_made >= worker->nclients) {
    ev_timer_stop(worker->loop, w);
  }
}
} // namespace

namespace {
// Called when an a connection has been inactive for a set period of time
// or a fixed amount of time after all requests have been made on a
// connection
void conn_timeout_cb(EV_P_ ev_timer *w, int revents) {
  auto client = static_cast<Client *>(w->data);

  ev_timer_stop(client->worker->loop, &client->conn_inactivity_watcher);
  ev_timer_stop(client->worker->loop, &client->conn_active_watcher);

  if (util::check_socket_connected(client->fd)) {
    client->timeout();
  }
}
} // namespace

namespace {
bool check_stop_client_request_timeout(Client *client, ev_timer *w) {
  auto nreq = client->req_todo - client->req_started;

  if (nreq == 0 ||
      client->streams.size() >= (size_t)config.max_concurrent_streams) {
    // no more requests to make, stop timer
    ev_timer_stop(client->worker->loop, w);
    return true;
  }

  return false;
}
} // namespace

namespace {
void client_request_timeout_cb(struct ev_loop *loop, ev_timer *w, int revents) {
  auto client = static_cast<Client *>(w->data);

  client->submit_request();
  client->signal_write();

  if (check_stop_client_request_timeout(client, w)) {
    return;
  }

  ev_tstamp duration =
      config.timings[client->reqidx] - config.timings[client->reqidx - 1];

  while (duration < 1e-9) {
    client->submit_request();
    client->signal_write();
    if (check_stop_client_request_timeout(client, w)) {
      return;
    }

    duration =
        config.timings[client->reqidx] - config.timings[client->reqidx - 1];
  }

  client->request_timeout_watcher.repeat = duration;
  ev_timer_again(client->worker->loop, &client->request_timeout_watcher);
}
} // namespace

Client::Client(Worker *worker, size_t req_todo)
    : worker(worker), ssl(nullptr), next_addr(config.addrs), reqidx(0),
      state(CLIENT_IDLE), first_byte_received(false), req_todo(req_todo),
      req_started(0), req_done(0), fd(-1) {
  ev_io_init(&wev, writecb, 0, EV_WRITE);
  ev_io_init(&rev, readcb, 0, EV_READ);

  wev.data = this;
  rev.data = this;

  ev_timer_init(&conn_inactivity_watcher, conn_timeout_cb, 0.,
                worker->config->conn_inactivity_timeout);
  conn_inactivity_watcher.data = this;

  ev_timer_init(&conn_active_watcher, conn_timeout_cb,
                worker->config->conn_active_timeout, 0.);
  conn_active_watcher.data = this;

  ev_timer_init(&request_timeout_watcher, client_request_timeout_cb, 0., 0.);
  request_timeout_watcher.data = this;
}

Client::~Client() {
  ev_timer_stop(worker->loop, &request_timeout_watcher);
  disconnect();
}

int Client::do_read() { return readfn(*this); }
int Client::do_write() { return writefn(*this); }

int Client::connect() {
  record_start_time(&worker->stats);

  if (worker->config->conn_inactivity_timeout > 0) {
    ev_timer_again(worker->loop, &conn_inactivity_watcher);
  }

  while (next_addr) {
    auto addr = next_addr;
    next_addr = next_addr->ai_next;
    fd = util::create_nonblock_socket(addr->ai_family);
    if (fd == -1) {
      continue;
    }
    if (config.scheme == "https") {
      ssl = SSL_new(worker->ssl_ctx);

      auto config = worker->config;

      if (!util::numeric_host(config->host.c_str())) {
        SSL_set_tlsext_host_name(ssl, config->host.c_str());
      }

      SSL_set_fd(ssl, fd);
      SSL_set_connect_state(ssl);
    }

    auto rv = ::connect(fd, addr->ai_addr, addr->ai_addrlen);
    if (rv != 0 && errno != EINPROGRESS) {
      if (ssl) {
        SSL_free(ssl);
        ssl = nullptr;
      }
      close(fd);
      fd = -1;
      continue;
    }
    break;
  }

  if (fd == -1) {
    return -1;
  }

  writefn = &Client::connected;

  ev_io_set(&rev, fd, EV_READ);
  ev_io_set(&wev, fd, EV_WRITE);

  ev_io_start(worker->loop, &wev);

  return 0;
}

void Client::timeout() {
  process_timedout_streams();

  disconnect();
}

void Client::restart_timeout() {
  if (worker->config->conn_inactivity_timeout > 0) {
    ev_timer_again(worker->loop, &conn_inactivity_watcher);
  }
}

void Client::fail() {
  process_abandoned_streams();

  disconnect();
}

void Client::disconnect() {
  ev_timer_stop(worker->loop, &conn_inactivity_watcher);
  ev_timer_stop(worker->loop, &conn_active_watcher);

  streams.clear();
  session.reset();
  state = CLIENT_IDLE;
  ev_io_stop(worker->loop, &wev);
  ev_io_stop(worker->loop, &rev);
  if (ssl) {
    SSL_set_shutdown(ssl, SSL_RECEIVED_SHUTDOWN);
    ERR_clear_error();
    SSL_shutdown(ssl);
    SSL_free(ssl);
    ssl = nullptr;
  }
  if (fd != -1) {
    shutdown(fd, SHUT_WR);
    close(fd);
    fd = -1;
  }
}

void Client::submit_request() {
  auto req_stat = &worker->stats.req_stats[worker->stats.req_started++];
  session->submit_request(req_stat);
  ++req_started;

  // if an active timeout is set and this is the last request to be submitted
  // on this connection, start the active timeout.
  if (worker->config->conn_active_timeout > 0 && req_started >= req_todo) {
    ev_timer_start(worker->loop, &conn_active_watcher);
  }
}

void Client::process_timedout_streams() {
  for (auto &req_stat : worker->stats.req_stats) {
    if (!req_stat.completed) {
      req_stat.stream_close_time = std::chrono::steady_clock::now();
    }
  }

  auto req_timed_out = req_todo - req_done;
  worker->stats.req_timedout += req_timed_out;

  process_abandoned_streams();
}

void Client::process_abandoned_streams() {
  auto req_abandoned = req_todo - req_done;

  worker->stats.req_failed += req_abandoned;
  worker->stats.req_error += req_abandoned;
  worker->stats.req_done += req_abandoned;

  req_done = req_todo;
}

void Client::report_progress() {
  if (!worker->config->is_rate_mode() && worker->id == 0 &&
      worker->stats.req_done % worker->progress_interval == 0) {
    std::cout << "progress: "
              << worker->stats.req_done * 100 / worker->stats.req_todo
              << "% done" << std::endl;
  }
}

namespace {
void print_server_tmp_key(SSL *ssl) {
// libressl does not have SSL_get_server_tmp_key
#if OPENSSL_VERSION_NUMBER >= 0x10002000L && defined(SSL_get_server_tmp_key)
  EVP_PKEY *key;

  if (!SSL_get_server_tmp_key(ssl, &key)) {
    return;
  }

  auto key_del = defer(EVP_PKEY_free, key);

  std::cout << "Server Temp Key: ";

  switch (EVP_PKEY_id(key)) {
  case EVP_PKEY_RSA:
    std::cout << "RSA " << EVP_PKEY_bits(key) << " bits" << std::endl;
    break;
  case EVP_PKEY_DH:
    std::cout << "DH " << EVP_PKEY_bits(key) << " bits" << std::endl;
    break;
  case EVP_PKEY_EC: {
    auto ec = EVP_PKEY_get1_EC_KEY(key);
    auto ec_del = defer(EC_KEY_free, ec);
    auto nid = EC_GROUP_get_curve_name(EC_KEY_get0_group(ec));
    auto cname = EC_curve_nid2nist(nid);
    if (!cname) {
      cname = OBJ_nid2sn(nid);
    }

    std::cout << "ECDH " << cname << " " << EVP_PKEY_bits(key) << " bits"
              << std::endl;
    break;
  }
  }
#endif // OPENSSL_VERSION_NUMBER >= 0x10002000L
}
} // namespace

void Client::report_tls_info() {
  if (worker->id == 0 && !worker->tls_info_report_done) {
    worker->tls_info_report_done = true;
    auto cipher = SSL_get_current_cipher(ssl);
    std::cout << "Protocol: " << ssl::get_tls_protocol(ssl) << "\n"
              << "Cipher: " << SSL_CIPHER_get_name(cipher) << std::endl;
    print_server_tmp_key(ssl);
  }
}

void Client::terminate_session() { session->terminate(); }

void Client::on_request(int32_t stream_id) { streams[stream_id] = Stream(); }

void Client::on_header(int32_t stream_id, const uint8_t *name, size_t namelen,
                       const uint8_t *value, size_t valuelen) {
  auto itr = streams.find(stream_id);
  if (itr == std::end(streams)) {
    return;
  }
  auto &stream = (*itr).second;
  if (stream.status_success == -1 && namelen == 7 &&
      util::streq_l(":status", name, namelen)) {
    int status = 0;
    for (size_t i = 0; i < valuelen; ++i) {
      if ('0' <= value[i] && value[i] <= '9') {
        status *= 10;
        status += value[i] - '0';
        if (status > 999) {
          stream.status_success = 0;
          return;
        }
      } else {
        break;
      }
    }

    if (status >= 200 && status < 300) {
      ++worker->stats.status[2];
      stream.status_success = 1;
    } else if (status < 400) {
      ++worker->stats.status[3];
      stream.status_success = 1;
    } else if (status < 600) {
      ++worker->stats.status[status / 100];
      stream.status_success = 0;
    } else {
      stream.status_success = 0;
    }
  }
}

void Client::on_stream_close(int32_t stream_id, bool success,
                             RequestStat *req_stat) {
  req_stat->stream_close_time = std::chrono::steady_clock::now();
  if (success) {
    req_stat->completed = true;
    ++worker->stats.req_success;
  }
  ++worker->stats.req_done;
  ++req_done;
  if (success && streams[stream_id].status_success == 1) {
    ++worker->stats.req_status_success;
  } else {
    ++worker->stats.req_failed;
  }
  report_progress();
  streams.erase(stream_id);
  if (req_done == req_todo) {
    terminate_session();
    return;
  }

  if (!config.timing_script) {
    if (req_started < req_todo) {
      submit_request();
      return;
    }
  }
}

int Client::connection_made() {
  if (ssl) {
    report_tls_info();

    const unsigned char *next_proto = nullptr;
    unsigned int next_proto_len;
    SSL_get0_next_proto_negotiated(ssl, &next_proto, &next_proto_len);
    for (int i = 0; i < 2; ++i) {
      if (next_proto) {
        if (util::check_h2_is_selected(next_proto, next_proto_len)) {
          session = make_unique<Http2Session>(this);
          break;
        }
#ifdef HAVE_SPDYLAY
        else {
          auto spdy_version =
              spdylay_npn_get_version(next_proto, next_proto_len);
          if (spdy_version) {
            session = make_unique<SpdySession>(this, spdy_version);
            break;
          }
        }
#endif // HAVE_SPDYLAY

        next_proto = nullptr;
        break;
      }

#if OPENSSL_VERSION_NUMBER >= 0x10002000L
      SSL_get0_alpn_selected(ssl, &next_proto, &next_proto_len);
#else  // OPENSSL_VERSION_NUMBER < 0x10002000L
      break;
#endif // OPENSSL_VERSION_NUMBER < 0x10002000L
    }

    if (!next_proto) {
      debug_nextproto_error();
      fail();
      return -1;
    }
  } else {
    switch (config.no_tls_proto) {
    case Config::PROTO_HTTP2:
      session = make_unique<Http2Session>(this);
      break;
#ifdef HAVE_SPDYLAY
    case Config::PROTO_SPDY2:
      session = make_unique<SpdySession>(this, SPDYLAY_PROTO_SPDY2);
      break;
    case Config::PROTO_SPDY3:
      session = make_unique<SpdySession>(this, SPDYLAY_PROTO_SPDY3);
      break;
    case Config::PROTO_SPDY3_1:
      session = make_unique<SpdySession>(this, SPDYLAY_PROTO_SPDY3_1);
      break;
#endif // HAVE_SPDYLAY
    default:
      // unreachable
      assert(0);
    }
  }

  state = CLIENT_CONNECTED;

  session->on_connect();

  record_connect_time(&worker->stats);

  if (!config.timing_script) {
    auto nreq =
        std::min(req_todo - req_started, (size_t)config.max_concurrent_streams);

    for (; nreq > 0; --nreq) {
      submit_request();
    }
  } else {

    ev_tstamp duration = config.timings[reqidx];

    while (duration < 1e-9) {
      submit_request();
      duration = config.timings[reqidx];
    }

    request_timeout_watcher.repeat = duration;
    ev_timer_again(worker->loop, &request_timeout_watcher);
  }
  signal_write();

  return 0;
}

int Client::on_read(const uint8_t *data, size_t len) {
  auto rv = session->on_read(data, len);
  if (rv != 0) {
    return -1;
  }
  worker->stats.bytes_total += len;
  signal_write();
  return 0;
}

int Client::on_write() {
  if (session->on_write() != 0) {
    return -1;
  }
  return 0;
}

int Client::read_clear() {
  uint8_t buf[8_k];

  for (;;) {
    ssize_t nread;
    while ((nread = read(fd, buf, sizeof(buf))) == -1 && errno == EINTR)
      ;
    if (nread == -1) {
      if (errno == EAGAIN || errno == EWOULDBLOCK) {
        return 0;
      }
      return -1;
    }

    if (nread == 0) {
      return -1;
    }

    if (on_read(buf, nread) != 0) {
      return -1;
    }

    if (!first_byte_received) {
      first_byte_received = true;
      record_ttfb(&worker->stats);
    }
  }

  return 0;
}

int Client::write_clear() {
  for (;;) {
    if (wb.rleft() > 0) {
      ssize_t nwrite;
      while ((nwrite = write(fd, wb.pos, wb.rleft())) == -1 && errno == EINTR)
        ;
      if (nwrite == -1) {
        if (errno == EAGAIN || errno == EWOULDBLOCK) {
          ev_io_start(worker->loop, &wev);
          return 0;
        }
        return -1;
      }
      wb.drain(nwrite);
      continue;
    }
    wb.reset();
    if (on_write() != 0) {
      return -1;
    }
    if (wb.rleft() == 0) {
      break;
    }
  }

  ev_io_stop(worker->loop, &wev);

  return 0;
}

int Client::connected() {
  if (!util::check_socket_connected(fd)) {
    return ERR_CONNECT_FAIL;
  }
  ev_io_start(worker->loop, &rev);
  ev_io_stop(worker->loop, &wev);

  if (ssl) {
    readfn = &Client::tls_handshake;
    writefn = &Client::tls_handshake;

    return do_write();
  }

  readfn = &Client::read_clear;
  writefn = &Client::write_clear;

  if (connection_made() != 0) {
    return -1;
  }

  return 0;
}

int Client::tls_handshake() {
  ERR_clear_error();

  auto rv = SSL_do_handshake(ssl);

  if (rv == 0) {
    return -1;
  }

  if (rv < 0) {
    auto err = SSL_get_error(ssl, rv);
    switch (err) {
    case SSL_ERROR_WANT_READ:
      ev_io_stop(worker->loop, &wev);
      return 0;
    case SSL_ERROR_WANT_WRITE:
      ev_io_start(worker->loop, &wev);
      return 0;
    default:
      return -1;
    }
  }

  ev_io_stop(worker->loop, &wev);

  readfn = &Client::read_tls;
  writefn = &Client::write_tls;

  if (connection_made() != 0) {
    return -1;
  }

  return 0;
}

int Client::read_tls() {
  uint8_t buf[8_k];

  ERR_clear_error();

  for (;;) {
    auto rv = SSL_read(ssl, buf, sizeof(buf));

    if (rv == 0) {
      return -1;
    }

    if (rv < 0) {
      auto err = SSL_get_error(ssl, rv);
      switch (err) {
      case SSL_ERROR_WANT_READ:
        return 0;
      case SSL_ERROR_WANT_WRITE:
        // renegotiation started
        return -1;
      default:
        return -1;
      }
    }

    if (on_read(buf, rv) != 0) {
      return -1;
    }

    if (!first_byte_received) {
      first_byte_received = true;
      record_ttfb(&worker->stats);
    }
  }
}

int Client::write_tls() {
  ERR_clear_error();

  for (;;) {
    if (wb.rleft() > 0) {
      auto rv = SSL_write(ssl, wb.pos, wb.rleft());

      if (rv == 0) {
        return -1;
      }

      if (rv < 0) {
        auto err = SSL_get_error(ssl, rv);
        switch (err) {
        case SSL_ERROR_WANT_READ:
          // renegotiation started
          return -1;
        case SSL_ERROR_WANT_WRITE:
          ev_io_start(worker->loop, &wev);
          return 0;
        default:
          return -1;
        }
      }

      wb.drain(rv);

      continue;
    }
    wb.reset();
    if (on_write() != 0) {
      return -1;
    }
    if (wb.rleft() == 0) {
      break;
    }
  }

  ev_io_stop(worker->loop, &wev);

  return 0;
}

void Client::record_request_time(RequestStat *req_stat) {
  req_stat->request_time = std::chrono::steady_clock::now();
}

void Client::record_start_time(Stats *stat) {
  stat->start_times.push_back(std::chrono::steady_clock::now());
}

void Client::record_connect_time(Stats *stat) {
  stat->connect_times.push_back(std::chrono::steady_clock::now());
}

void Client::record_ttfb(Stats *stat) {
  stat->ttfbs.push_back(std::chrono::steady_clock::now());
}

void Client::signal_write() { ev_io_start(worker->loop, &wev); }

Worker::Worker(uint32_t id, SSL_CTX *ssl_ctx, size_t req_todo, size_t nclients,
               size_t rate, Config *config)
    : stats(req_todo), loop(ev_loop_new(0)), ssl_ctx(ssl_ctx), config(config),
      id(id), tls_info_report_done(false), nconns_made(0), nclients(nclients),
      rate(rate) {
  stats.req_todo = req_todo;
  progress_interval = std::max(static_cast<size_t>(1), req_todo / 10);
  auto nreqs_per_client = req_todo / nclients;
  auto nreqs_rem = req_todo % nclients;

  // create timer that will go off every second
  ev_timer_init(&timeout_watcher, second_timeout_w_cb, 0., 1.);
  timeout_watcher.data = this;

  if (!config->is_rate_mode()) {
    for (size_t i = 0; i < nclients; ++i) {
      auto req_todo = nreqs_per_client;
      if (nreqs_rem > 0) {
        ++req_todo;
        --nreqs_rem;
      }
      clients.push_back(make_unique<Client>(this, req_todo));
    }
  }
}

Worker::~Worker() {
  ev_timer_stop(loop, &timeout_watcher);

  // first clear clients so that io watchers are stopped before
  // destructing ev_loop.
  clients.clear();
  ev_loop_destroy(loop);
}

void Worker::run() {
  if (!config->is_rate_mode()) {
    for (auto &client : clients) {
      if (client->connect() != 0) {
        std::cerr << "client could not connect to host" << std::endl;
        client->fail();
      }
    }
  } else {
    ev_timer_again(loop, &timeout_watcher);

    // call callback so that we don't waste the first second
    second_timeout_w_cb(loop, &timeout_watcher, 0);
  }
  ev_run(loop, 0);
}

namespace {
// Returns percentage of number of samples within mean +/- sd.
template <typename Duration>
double within_sd(const std::vector<Duration> &samples, const Duration &mean,
                 const Duration &sd) {
  if (samples.size() == 0) {
    return 0.0;
  }
  auto lower = mean - sd;
  auto upper = mean + sd;
  auto m = std::count_if(
      std::begin(samples), std::end(samples),
      [&lower, &upper](const Duration &t) { return lower <= t && t <= upper; });
  return (m / static_cast<double>(samples.size())) * 100;
}
} // namespace

namespace {
// Computes statistics using |samples|. The min, max, mean, sd, and
// percentage of number of samples within mean +/- sd are computed.
template <typename Duration>
TimeStat<Duration> compute_time_stat(const std::vector<Duration> &samples) {
  if (samples.empty()) {
    return {Duration::zero(), Duration::zero(), Duration::zero(),
            Duration::zero(), 0.0};
  }
  // standard deviation calculated using Rapid calculation method:
  // http://en.wikipedia.org/wiki/Standard_deviation#Rapid_calculation_methods
  double a = 0, q = 0;
  size_t n = 0;
  int64_t sum = 0;
  auto res = TimeStat<Duration>{Duration::max(), Duration::min()};
  for (const auto &t : samples) {
    ++n;
    res.min = std::min(res.min, t);
    res.max = std::max(res.max, t);
    sum += t.count();

    auto na = a + (t.count() - a) / n;
    q += (t.count() - a) * (t.count() - na);
    a = na;
  }

  assert(n > 0);
  res.mean = Duration(sum / n);
  res.sd = Duration(static_cast<typename Duration::rep>(sqrt(q / n)));
  res.within_sd = within_sd(samples, res.mean, res.sd);

  return res;
}
} // namespace

namespace {
TimeStats
process_time_stats(const std::vector<std::unique_ptr<Worker>> &workers) {
  size_t nrequest_times = 0, nttfb_times = 0;
  for (const auto &w : workers) {
    nrequest_times += w->stats.req_stats.size();
    nttfb_times += w->stats.ttfbs.size();
  }

  std::vector<std::chrono::microseconds> request_times;
  request_times.reserve(nrequest_times);
  std::vector<std::chrono::microseconds> connect_times, ttfb_times;
  connect_times.reserve(nttfb_times);
  ttfb_times.reserve(nttfb_times);

  for (const auto &w : workers) {
    for (const auto &req_stat : w->stats.req_stats) {
      if (!req_stat.completed) {
        continue;
      }
      request_times.push_back(
          std::chrono::duration_cast<std::chrono::microseconds>(
              req_stat.stream_close_time - req_stat.request_time));
    }

    const auto &stat = w->stats;
    // rule out cases where we started but didn't connect or get the
    // first byte (errors).  We will get connect event before FFTB.
    assert(stat.start_times.size() >= stat.ttfbs.size());
    assert(stat.connect_times.size() >= stat.ttfbs.size());
    for (size_t i = 0; i < stat.ttfbs.size(); ++i) {
      connect_times.push_back(
          std::chrono::duration_cast<std::chrono::microseconds>(
              stat.connect_times[i] - stat.start_times[i]));

      ttfb_times.push_back(
          std::chrono::duration_cast<std::chrono::microseconds>(
              stat.ttfbs[i] - stat.start_times[i]));
    }
  }

  return {compute_time_stat(request_times), compute_time_stat(connect_times),
          compute_time_stat(ttfb_times)};
}
} // namespace

namespace {
void resolve_host() {
  int rv;
  addrinfo hints{}, *res;

  hints.ai_family = AF_UNSPEC;
  hints.ai_socktype = SOCK_STREAM;
  hints.ai_protocol = 0;
  hints.ai_flags = AI_ADDRCONFIG;

  rv = getaddrinfo(config.host.c_str(), util::utos(config.port).c_str(), &hints,
                   &res);
  if (rv != 0) {
    std::cerr << "getaddrinfo() failed: " << gai_strerror(rv) << std::endl;
    exit(EXIT_FAILURE);
  }
  if (res == nullptr) {
    std::cerr << "No address returned" << std::endl;
    exit(EXIT_FAILURE);
  }
  config.addrs = res;
}
} // namespace

namespace {
std::string get_reqline(const char *uri, const http_parser_url &u) {
  std::string reqline;

  if (util::has_uri_field(u, UF_PATH)) {
    reqline = util::get_uri_field(uri, u, UF_PATH);
  } else {
    reqline = "/";
  }

  if (util::has_uri_field(u, UF_QUERY)) {
    reqline += "?";
    reqline += util::get_uri_field(uri, u, UF_QUERY);
  }

  return reqline;
}
} // 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 (util::select_h2(const_cast<const unsigned char **>(out), outlen, in,
                      inlen)) {
    return SSL_TLSEXT_ERR_OK;
  }
#ifdef HAVE_SPDYLAY
  if (spdylay_select_next_protocol(out, outlen, in, inlen) > 0) {
    return SSL_TLSEXT_ERR_OK;
  }
#endif
  return SSL_TLSEXT_ERR_NOACK;
}
} // namespace

namespace {
bool parse_base_uri(std::string base_uri) {
  http_parser_url u{};
  if (http_parser_parse_url(base_uri.c_str(), base_uri.size(), 0, &u) != 0 ||
      !util::has_uri_field(u, UF_SCHEMA) || !util::has_uri_field(u, UF_HOST)) {
    return false;
  }

  config.scheme = util::get_uri_field(base_uri.c_str(), u, UF_SCHEMA);
  config.host = util::get_uri_field(base_uri.c_str(), u, UF_HOST);
  config.default_port = util::get_default_port(base_uri.c_str(), u);
  if (util::has_uri_field(u, UF_PORT)) {
    config.port = u.port;
  } else {
    config.port = config.default_port;
  }

  return true;
}
} // namespace
namespace {
// Use std::vector<std::string>::iterator explicitly, without that,
// http_parser_url u{} fails with clang-3.4.
std::vector<std::string> parse_uris(std::vector<std::string>::iterator first,
                                    std::vector<std::string>::iterator last) {
  std::vector<std::string> reqlines;

  if (first == last) {
    std::cerr << "no URI available" << std::endl;
    exit(EXIT_FAILURE);
  }

  if (!config.has_base_uri()) {

    if (!parse_base_uri(*first)) {
      std::cerr << "invalid URI: " << *first << std::endl;
      exit(EXIT_FAILURE);
    }

    config.base_uri = *first;
  }

  for (; first != last; ++first) {
    http_parser_url u{};

    auto uri = (*first).c_str();

    if (http_parser_parse_url(uri, (*first).size(), 0, &u) != 0) {
      std::cerr << "invalid URI: " << uri << std::endl;
      exit(EXIT_FAILURE);
    }

    reqlines.push_back(get_reqline(uri, u));
  }

  return reqlines;
}
} // namespace

namespace {
std::vector<std::string> read_uri_from_file(std::istream &infile) {
  std::vector<std::string> uris;
  std::string line_uri;
  while (std::getline(infile, line_uri)) {
    uris.push_back(line_uri);
  }

  return uris;
}
} // namespace

namespace {
void read_script_from_file(std::istream &infile,
                           std::vector<ev_tstamp> &timings,
                           std::vector<std::string> &uris) {
  std::string script_line;
  int line_count = 0;
  while (std::getline(infile, script_line)) {
    line_count++;
    if (script_line.empty()) {
      std::cerr << "Empty line detected at line " << line_count
                << ". Ignoring and continuing." << std::endl;
      continue;
    }

    std::size_t pos = script_line.find("\t");
    if (pos == std::string::npos) {
      std::cerr << "Invalid line format detected, no tab character at line "
                << line_count << ". \n\t" << script_line << std::endl;
      exit(EXIT_FAILURE);
    }

    const char *start = script_line.c_str();
    char *end;
    auto v = std::strtod(start, &end);

    if (end == start || errno != 0) {
      std::cerr << "Time value error at line " << line_count << ". \n\t"
                << script_line.substr(0, pos) << std::endl;
      exit(EXIT_FAILURE);
    }

    timings.push_back(v / 1000.0);
    uris.push_back(script_line.substr(pos + 1, script_line.size()));
  }
}
} // namespace

namespace {
void print_version(std::ostream &out) {
  out << "h2load nghttp2/" NGHTTP2_VERSION << std::endl;
}
} // namespace

namespace {
void print_usage(std::ostream &out) {
  out << R"(Usage: h2load [OPTIONS]... [URI]...
benchmarking tool for HTTP/2 and SPDY server)" << std::endl;
}
} // namespace

namespace {
void print_help(std::ostream &out) {
  print_usage(out);

  auto config = Config();

  out << R"(
  <URI>       Specify URI to access.   Multiple URIs can be specified.
              URIs are used  in this order for each  client.  All URIs
              are used, then  first URI is used and then  2nd URI, and
              so  on.  The  scheme, host  and port  in the  subsequent
              URIs, if present,  are ignored.  Those in  the first URI
              are used solely.  Definition of a base URI overrides all
              scheme, host or port values.
Options:
  -n, --requests=<N>
              Number of requests.
              Default: )" << config.nreqs << R"(
  -c, --clients=<N>
              Number of concurrent clients.
              Default: )" << config.nclients << R"(
  -t, --threads=<N>
              Number of native threads.
              Default: )" << config.nthreads << R"(
  -i, --input-file=<PATH>
              Path of a file with multiple URIs are separated by EOLs.
              This option will disable URIs getting from command-line.
              If '-' is given as <PATH>, URIs will be read from stdin.
              URIs are used  in this order for each  client.  All URIs
              are used, then  first URI is used and then  2nd URI, and
              so  on.  The  scheme, host  and port  in the  subsequent
              URIs, if present,  are ignored.  Those in  the first URI
              are used solely.  Definition of a base URI overrides all
              scheme, host or port values.
  -m, --max-concurrent-streams=(auto|<N>)
              Max concurrent streams to  issue per session.  If "auto"
              is given, the number of given URIs is used.
              Default: auto
  -w, --window-bits=<N>
              Sets the stream level initial window size to (2**<N>)-1.
              For SPDY, 2**<N> is used instead.
              Default: )" << config.window_bits << R"(
  -W, --connection-window-bits=<N>
              Sets  the  connection  level   initial  window  size  to
              (2**<N>)-1.  For SPDY, if <N>  is strictly less than 16,
              this option  is ignored.   Otherwise 2**<N> is  used for
              SPDY.
              Default: )" << config.connection_window_bits << R"(
  -H, --header=<HEADER>
              Add/Override a header to the requests.
  --ciphers=<SUITE>
              Set allowed  cipher list.  The  format of the  string is
              described in OpenSSL ciphers(1).
  -p, --no-tls-proto=<PROTOID>
              Specify ALPN identifier of the  protocol to be used when
              accessing http URI without SSL/TLS.)";

#ifdef HAVE_SPDYLAY
  out << R"(
              Available protocols: spdy/2, spdy/3, spdy/3.1 and )";
#else  // !HAVE_SPDYLAY
  out << R"(
              Available protocol: )";
#endif // !HAVE_SPDYLAY
  out << NGHTTP2_CLEARTEXT_PROTO_VERSION_ID << R"(
              Default: )" << NGHTTP2_CLEARTEXT_PROTO_VERSION_ID << R"(
  -d, --data=<PATH>
              Post FILE to  server.  The request method  is changed to
              POST.
  -r, --rate=<N>
              Specifies  the  fixed  rate  at  which  connections  are
              created.   The   rate  must   be  a   positive  integer,
              representing the  number of  connections to be  made per
              second.  When the rate is 0,  the program will run as it
              normally does, creating connections at whatever variable
              rate it wants.  The default value for this option is 0.
  -C, --num-conns=<N>
              Specifies  the total  number of  connections to  create.
              The  total  number of  connections  must  be a  positive
              integer.  On each connection, -m requests are made.  The
              test  stops once  as soon  as the  <N> connections  have
              either  completed   or  failed.   When  the   number  of
              connections is  0, the program  will run as  it normally
              does, creating as many connections  as it needs in order
              to make  the -n  requests specified.  The  default value
              for this option is 0.  The  -n option is not required if
              the -C option is being used.
  -T, --connection-active-timeout=<N>
              Specifies  the maximum  time that  h2load is  willing to
              keep a  connection open,  regardless of the  activity on
              said  connection.   <N>  must  be  a  positive  integer,
              specifying  the  number of  seconds  to  wait.  When  no
              timeout value is set (either active or inactive), h2load
              will keep a connection  open indefinitely, waiting for a
              response.
  -N, --connection-inactivity-timeout=<N>
              Specifies the amount  of time that h2load  is willing to
              wait to see activity on a given connection.  <N> must be
              a positive integer, specifying  the number of seconds to
              wait.  When  no timeout value  is set (either  active or
              inactive),   h2load   will   keep  a   connection   open
              indefinitely, waiting for a response.
  --timing-script-file=<PATH>
              Path of a file containing one  or more lines separated by
              EOLs. Each script line  is composed of  two tab-separated
              fields. The first field  represents  the time offset from
              the  start of  execution, expressed  as milliseconds with
              microsecond  resolution.  The second field represents the
              URI.   This   option  will   disable  URIs  getting  from
              command-line.  If '-'  is given as <PATH>,  script  lines
              will be read from stdin.  Script lines are used  in order
              for each  client.  If  -n is  given, it must be less than
              or equal to the number of script lines, larger values are
              clamped  to  the   number  of  script  lines.  If  -n  is
              not given,  the number of requests  will  default to  the
              number of script lines. The scheme, host and port defined
              in the  first URI  are used  solely.  Values contained in
              other URIs, if  present, are  ignored.  Definition  of  a
              base  URI  overrides  all  scheme, host  or port  values.
  -B, --base-uri=<URI>
              Specify URI from which the scheme, host and port will be
              used  for  all requests.   The  base  URI overrides  all
              values  defined either  at  the command  line or  inside
              input files.
  -v, --verbose
              Output debug information.
  --version   Display version information and exit.
  -h, --help  Display this help and exit.)" << std::endl;
}
} // namespace

int main(int argc, char **argv) {
#ifndef NOTHREADS
  ssl::LibsslGlobalLock lock;
#endif // NOTHREADS
  SSL_load_error_strings();
  SSL_library_init();
  OpenSSL_add_all_algorithms();
  OPENSSL_config(nullptr);

  std::string datafile;
  bool nreqs_set_manually = false;
  while (1) {
    static int flag = 0;
    static option long_options[] = {
        {"requests", required_argument, nullptr, 'n'},
        {"clients", required_argument, nullptr, 'c'},
        {"data", required_argument, nullptr, 'd'},
        {"threads", required_argument, nullptr, 't'},
        {"max-concurrent-streams", required_argument, nullptr, 'm'},
        {"window-bits", required_argument, nullptr, 'w'},
        {"connection-window-bits", required_argument, nullptr, 'W'},
        {"input-file", required_argument, nullptr, 'i'},
        {"header", required_argument, nullptr, 'H'},
        {"no-tls-proto", required_argument, nullptr, 'p'},
        {"verbose", no_argument, nullptr, 'v'},
        {"help", no_argument, nullptr, 'h'},
        {"version", no_argument, &flag, 1},
        {"ciphers", required_argument, &flag, 2},
        {"rate", required_argument, nullptr, 'r'},
        {"num-conns", required_argument, nullptr, 'C'},
        {"connection-active-timeout", required_argument, nullptr, 'T'},
        {"connection-inactivity-timeout", required_argument, nullptr, 'N'},
        {"timing-script-file", required_argument, &flag, 3},
        {"base-uri", required_argument, nullptr, 'B'},
        {nullptr, 0, nullptr, 0}};
    int option_index = 0;
    auto c = getopt_long(argc, argv, "hvW:c:d:m:n:p:t:w:H:i:r:C:T:N:B:",
                         long_options, &option_index);
    if (c == -1) {
      break;
    }
    switch (c) {
    case 'n':
      config.nreqs = strtoul(optarg, nullptr, 10);
      nreqs_set_manually = true;
      break;
    case 'c':
      config.nclients = strtoul(optarg, nullptr, 10);
      break;
    case 'd':
      datafile = optarg;
      break;
    case 't':
#ifdef NOTHREADS
      std::cerr << "-t: WARNING: Threading disabled at build time, "
                << "no threads created." << std::endl;
#else
      config.nthreads = strtoul(optarg, nullptr, 10);
#endif // NOTHREADS
      break;
    case 'm':
      if (util::strieq("auto", optarg)) {
        config.max_concurrent_streams = -1;
      } else {
        config.max_concurrent_streams = strtoul(optarg, nullptr, 10);
      }
      break;
    case 'w':
    case 'W': {
      errno = 0;
      char *endptr = nullptr;
      auto 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.custom_headers.emplace_back(header, value);
      util::inp_strlower(config.custom_headers.back().name);
      break;
    }
    case 'i':
      config.ifile = optarg;
      break;
    case 'p':
      if (util::strieq(NGHTTP2_CLEARTEXT_PROTO_VERSION_ID, optarg)) {
        config.no_tls_proto = Config::PROTO_HTTP2;
#ifdef HAVE_SPDYLAY
      } else if (util::strieq("spdy/2", optarg)) {
        config.no_tls_proto = Config::PROTO_SPDY2;
      } else if (util::strieq("spdy/3", optarg)) {
        config.no_tls_proto = Config::PROTO_SPDY3;
      } else if (util::strieq("spdy/3.1", optarg)) {
        config.no_tls_proto = Config::PROTO_SPDY3_1;
#endif // HAVE_SPDYLAY
      } else {
        std::cerr << "-p: unsupported protocol " << optarg << std::endl;
        exit(EXIT_FAILURE);
      }
      break;
    case 'r':
      config.rate = strtoul(optarg, nullptr, 10);
      if (config.rate == 0) {
        std::cerr << "-r: the rate at which connections are made "
                  << "must be positive." << std::endl;
        exit(EXIT_FAILURE);
      }
      break;
    case 'C':
      config.nconns = strtoul(optarg, nullptr, 10);
      if (config.nconns == 0) {
        std::cerr << "-C: the total number of connections made "
                  << "must be positive." << std::endl;
        exit(EXIT_FAILURE);
      }
      break;
    case 'T':
      config.conn_active_timeout = strtoul(optarg, nullptr, 10);
      if (config.conn_active_timeout <= 0) {
        std::cerr << "-T: the conn_active_timeout wait time "
                  << "must be positive." << std::endl;
        exit(EXIT_FAILURE);
      }
      break;
    case 'N':
      config.conn_inactivity_timeout = strtoul(optarg, nullptr, 10);
      if (config.conn_inactivity_timeout <= 0) {
        std::cerr << "-N: the conn_inactivity_timeout wait time "
                  << "must be positive." << std::endl;
        exit(EXIT_FAILURE);
      }
      break;
    case 'B':
      if (!parse_base_uri(optarg)) {
        std::cerr << "invalid base URI: " << optarg << std::endl;
        exit(EXIT_FAILURE);
      }
      config.base_uri = optarg;
      break;
    case 'v':
      config.verbose = true;
      break;
    case 'h':
      print_help(std::cout);
      exit(EXIT_SUCCESS);
    case '?':
      util::show_candidates(argv[optind - 1], long_options);
      exit(EXIT_FAILURE);
    case 0:
      switch (flag) {
      case 1:
        // version option
        print_version(std::cout);
        exit(EXIT_SUCCESS);
      case 2:
        // ciphers option
        config.ciphers = optarg;
        break;
      case 3:
        config.ifile = optarg;
        config.timing_script = true;
        break;
      }
      break;
    default:
      break;
    }
  }

  if (argc == optind) {
    if (config.ifile.empty()) {
      std::cerr << "no URI or input file given" << std::endl;
      exit(EXIT_FAILURE);
    }
  }

  if (config.nclients == 0) {
    std::cerr << "-c: the number of clients must be strictly greater than 0."
              << std::endl;
    exit(EXIT_FAILURE);
  }

  if (config.timing_script && config.is_rate_mode()) {
    std::cerr << "--timing-script, -r: these options cannot be used together."
              << std::endl;
    exit(EXIT_FAILURE);
  }

  std::vector<std::string> reqlines;

  if (config.ifile.empty()) {
    std::vector<std::string> uris;
    std::copy(&argv[optind], &argv[argc], std::back_inserter(uris));
    reqlines = parse_uris(std::begin(uris), std::end(uris));
  } else {
    std::vector<std::string> uris;
    if (config.ifile == "-") {
      if (!config.timing_script) {
        uris = read_uri_from_file(std::cin);
      } else {
        read_script_from_file(std::cin, config.timings, uris);
      }
    } else {
      std::ifstream infile(config.ifile);
      if (!infile) {
        std::cerr << "cannot read input file: " << config.ifile << std::endl;
        exit(EXIT_FAILURE);
      }

      if (!config.timing_script) {
        uris = read_uri_from_file(infile);
      } else {
        read_script_from_file(infile, config.timings, uris);
        if (nreqs_set_manually) {
          if (config.nreqs > uris.size()) {
            std::cerr
                << "-n: the number of requests must be less than or equal "
                   "to the number of timing script entries. Setting number "
                   "of requests to " << uris.size() << std::endl;

            config.nreqs = uris.size();
          }
        } else {
          // each client will execute the full script, so scale nreqs
          config.nreqs = uris.size() * config.nclients;
        }
      }
    }

    reqlines = parse_uris(std::begin(uris), std::end(uris));
  }

  if (reqlines.empty()) {
    std::cerr << "No URI given" << std::endl;
    exit(EXIT_FAILURE);
  }

  if (config.max_concurrent_streams == -1) {
    config.max_concurrent_streams = reqlines.size();
  }

  assert(config.max_concurrent_streams > 0);
  if (config.nreqs == 0) {
    std::cerr << "-n: the number of requests must be strictly greater than 0."
              << std::endl;
    exit(EXIT_FAILURE);
  }

  if (config.max_concurrent_streams == 0) {
    std::cerr << "-m: the max concurrent streams must be strictly greater "
              << "than 0." << std::endl;
    exit(EXIT_FAILURE);
  }

  if (config.nthreads == 0) {
    std::cerr << "-t: the number of threads must be strictly greater than 0."
              << std::endl;
    exit(EXIT_FAILURE);
  }

  if (config.nthreads > std::thread::hardware_concurrency()) {
    std::cerr << "-t: warning: the number of threads is greater than hardware "
              << "cores." << std::endl;
  }

  if (!config.is_rate_mode()) {
    if (config.nreqs < config.nclients) {
      std::cerr << "-n, -c: the number of requests must be greater than or "
                << "equal to the concurrent clients." << std::endl;
      exit(EXIT_FAILURE);
    }

    if (config.nclients < config.nthreads) {
      std::cerr << "-c, -t: the number of client must be greater than or equal "
                   "to the number of threads." << std::endl;
      exit(EXIT_FAILURE);
    }
  } else {
    if (config.rate < config.nthreads) {
      std::cerr << "-r, -t: the connection rate must be greater than or equal "
                << "to the number of threads." << std::endl;
      exit(EXIT_FAILURE);
    }

    if (nreqs_set_manually && config.rate > config.nreqs) {
      std::cerr << "-r, -n: the connection rate must be smaller than or equal "
                   "to the number of requests." << std::endl;
      exit(EXIT_FAILURE);
    }

    if (config.nconns != 0 && config.nconns < config.nthreads) {
      std::cerr
          << "-C, -t: the total number of connections must be greater than "
             "or equal "
          << "to the number of threads." << std::endl;
      exit(EXIT_FAILURE);
    }

    if (config.nconns == 0 && !nreqs_set_manually) {
      std::cerr << "-r: the rate option must be used with either the -n option "
                   "or the -C option." << std::endl;
      exit(EXIT_FAILURE);
    }
  }

  if (!datafile.empty()) {
    config.data_fd = open(datafile.c_str(), O_RDONLY | O_BINARY);
    if (config.data_fd == -1) {
      std::cerr << "-d: Could not open file " << datafile << std::endl;
      exit(EXIT_FAILURE);
    }
    struct stat data_stat;
    if (fstat(config.data_fd, &data_stat) == -1) {
      std::cerr << "-d: Could not stat file " << datafile << std::endl;
      exit(EXIT_FAILURE);
    }
    config.data_length = data_stat.st_size;
  }

  struct sigaction act {};
  act.sa_handler = SIG_IGN;
  sigaction(SIGPIPE, &act, nullptr);

  auto ssl_ctx = SSL_CTX_new(SSLv23_client_method());
  if (!ssl_ctx) {
    std::cerr << "Failed to create SSL_CTX: "
              << ERR_error_string(ERR_get_error(), nullptr) << std::endl;
    exit(EXIT_FAILURE);
  }

  auto ssl_opts = (SSL_OP_ALL & ~SSL_OP_DONT_INSERT_EMPTY_FRAGMENTS) |
                  SSL_OP_NO_SSLv2 | SSL_OP_NO_SSLv3 | SSL_OP_NO_COMPRESSION |
                  SSL_OP_NO_SESSION_RESUMPTION_ON_RENEGOTIATION;

  SSL_CTX_set_options(ssl_ctx, ssl_opts);
  SSL_CTX_set_mode(ssl_ctx, SSL_MODE_AUTO_RETRY);
  SSL_CTX_set_mode(ssl_ctx, SSL_MODE_RELEASE_BUFFERS);

  const char *ciphers;
  if (config.ciphers.empty()) {
    ciphers = ssl::DEFAULT_CIPHER_LIST;
  } else {
    ciphers = config.ciphers.c_str();
  }

  if (SSL_CTX_set_cipher_list(ssl_ctx, ciphers) == 0) {
    std::cerr << "SSL_CTX_set_cipher_list with " << ciphers
              << " failed: " << ERR_error_string(ERR_get_error(), nullptr)
              << std::endl;
    exit(EXIT_FAILURE);
  }

  SSL_CTX_set_next_proto_select_cb(ssl_ctx, client_select_next_proto_cb,
                                   nullptr);

#if OPENSSL_VERSION_NUMBER >= 0x10002000L
  auto proto_list = util::get_default_alpn();
#ifdef HAVE_SPDYLAY
  static const char spdy_proto_list[] = "\x8spdy/3.1\x6spdy/3\x6spdy/2";
  std::copy_n(spdy_proto_list, sizeof(spdy_proto_list) - 1,
              std::back_inserter(proto_list));
#endif // HAVE_SPDYLAY
  SSL_CTX_set_alpn_protos(ssl_ctx, proto_list.data(), proto_list.size());
#endif // OPENSSL_VERSION_NUMBER >= 0x10002000L

  // if not in rate mode and -C is set, warn that we are ignoring it
  if (!config.is_rate_mode() && config.nconns != 0) {
    std::cerr << "-C: warning: This option can only be used with -r, and"
              << " will be ignored otherwise." << std::endl;
  }

  size_t n_time = 0;
  size_t c_time = 0;
  size_t actual_nreqs = config.nreqs;
  // only care about n_time and c_time in rate mode
  if (config.is_rate_mode()) {
    n_time = config.nreqs / (config.rate * config.max_concurrent_streams);
    c_time = config.nconns / config.rate;

    // check to see if the two ways of determining test time conflict
    if (n_time != c_time && config.nconns != 0) {
      if (config.nreqs != 1) {
        if (config.nreqs < config.nconns) {
          std::cerr << "-C, -n: warning: number of requests conflict. "
                    << std::endl;
          std::cerr << "The test will create "
                    << (config.max_concurrent_streams * config.nconns)
                    << " total requests." << std::endl;
          actual_nreqs = config.max_concurrent_streams * config.nconns;
        } else {
          std::cout << "-C, -n: warning: number of requests conflict. "
                    << std::endl;
          std::cout
              << "The smaller of the two will be chosen and the test will "
              << "create "
              << std::min(config.nreqs,
                          static_cast<size_t>(config.max_concurrent_streams *
                                              config.nconns))
              << " total requests." << std::endl;
          actual_nreqs = std::min(
              config.nreqs, static_cast<size_t>(config.max_concurrent_streams *
                                                config.nreqs));
        }
      } else {
        actual_nreqs = config.max_concurrent_streams * config.nconns;
      }
    }
  }

  Headers shared_nva;
  shared_nva.emplace_back(":scheme", config.scheme);
  if (config.port != config.default_port) {
    shared_nva.emplace_back(":authority",
                            config.host + ":" + util::utos(config.port));
  } else {
    shared_nva.emplace_back(":authority", config.host);
  }
  shared_nva.emplace_back(":method", config.data_fd == -1 ? "GET" : "POST");
  shared_nva.emplace_back("user-agent", "h2load nghttp2/" NGHTTP2_VERSION);

  // list overridalbe headers
  auto override_hdrs =
      make_array<std::string>(":authority", ":host", ":method", ":scheme");

  for (auto &kv : config.custom_headers) {
    if (std::find(std::begin(override_hdrs), std::end(override_hdrs),
                  kv.name) != std::end(override_hdrs)) {
      // override header
      for (auto &nv : shared_nva) {
        if ((nv.name == ":authority" && kv.name == ":host") ||
            (nv.name == kv.name)) {
          nv.value = kv.value;
        }
      }
    } else {
      // add additional headers
      shared_nva.push_back(kv);
    }
  }

  for (auto &req : reqlines) {
    // For nghttp2
    std::vector<nghttp2_nv> nva;

    nva.push_back(http2::make_nv_ls(":path", req));

    for (auto &nv : shared_nva) {
      nva.push_back(http2::make_nv(nv.name, nv.value, false));
    }

    config.nva.push_back(std::move(nva));

    // For spdylay
    std::vector<const char *> cva;

    cva.push_back(":path");
    cva.push_back(req.c_str());

    for (auto &nv : shared_nva) {
      if (nv.name == ":authority") {
        cva.push_back(":host");
      } else {
        cva.push_back(nv.name.c_str());
      }
      cva.push_back(nv.value.c_str());
    }
    cva.push_back(":version");
    cva.push_back("HTTP/1.1");
    cva.push_back(nullptr);

    config.nv.push_back(std::move(cva));
  }

  resolve_host();

  if (!config.is_rate_mode() && config.nclients == 1) {
    config.nthreads = 1;
  }
  ssize_t seconds = 0;

  if (config.is_rate_mode()) {

    // set various config values
    if (config.nreqs < config.nconns) {
      seconds = c_time;
    } else if (config.nconns == 0) {
      seconds = n_time;
    } else {
      seconds = std::min(n_time, c_time);
    }
    config.nreqs = actual_nreqs;
  }

  size_t nreqs_per_thread = config.nreqs / config.nthreads;
  ssize_t nreqs_rem = config.nreqs % config.nthreads;

  size_t nclients_per_thread = config.nclients / config.nthreads;
  ssize_t nclients_rem = config.nclients % config.nthreads;

  size_t rate_per_thread = config.rate / config.nthreads;
  ssize_t rate_per_thread_rem = config.rate % config.nthreads;

  size_t nclients_extra_per_thread = 0;
  ssize_t nclients_extra_per_thread_rem = 0;
  // In rate mode, we want each Worker to create a total of
  // C/t connections.
  if (config.is_rate_mode() && config.nconns > seconds * config.rate) {
    auto nclients_extra = config.nconns - (seconds * config.rate);
    nclients_extra_per_thread = nclients_extra / config.nthreads;
    nclients_extra_per_thread_rem = nclients_extra % config.nthreads;
  }

  std::cout << "starting benchmark..." << std::endl;

  auto start = std::chrono::steady_clock::now();

  std::vector<std::unique_ptr<Worker>> workers;

  workers.reserve(config.nthreads);
#ifndef NOTHREADS
  std::vector<std::future<void>> futures;
  for (size_t i = 0; i < config.nthreads - 1; ++i) {
    auto rate = rate_per_thread + (rate_per_thread_rem-- > 0);
    size_t nreqs;
    size_t nclients;
    if (!config.is_rate_mode()) {
      nclients = nclients_per_thread + (nclients_rem-- > 0);
      nreqs = nreqs_per_thread + (nreqs_rem-- > 0);
    } else {
      nclients = rate * seconds + nclients_extra_per_thread +
                 (nclients_extra_per_thread_rem-- > 0);
      nreqs = nclients * config.max_concurrent_streams;
    }
    std::cout << "spawning thread #" << i << ": " << nclients
              << " concurrent clients, " << nreqs << " total requests"
              << std::endl;
    workers.push_back(
        make_unique<Worker>(i, ssl_ctx, nreqs, nclients, rate, &config));
    auto &worker = workers.back();
    futures.push_back(
        std::async(std::launch::async, [&worker]() { worker->run(); }));
  }
#endif // NOTHREADS

  auto rate_last = rate_per_thread + (rate_per_thread_rem-- > 0);
  size_t nclients_last;
  size_t nreqs_last;
  if (!config.is_rate_mode()) {
    nclients_last = nclients_per_thread + (nclients_rem-- > 0);
    nreqs_last = nreqs_per_thread + (nreqs_rem-- > 0);
  } else {
    nclients_last = rate_last * seconds + nclients_extra_per_thread +
                    (nclients_extra_per_thread_rem-- > 0);
    nreqs_last = nclients_last * config.max_concurrent_streams;
  }
  std::cout << "spawning thread #" << (config.nthreads - 1) << ": "
            << nclients_last << " concurrent clients, " << nreqs_last
            << " total requests" << std::endl;
  workers.push_back(make_unique<Worker>(config.nthreads - 1, ssl_ctx,
                                        nreqs_last, nclients_last, rate_last,
                                        &config));
  workers.back()->run();

#ifndef NOTHREADS
  for (auto &fut : futures) {
    fut.get();
  }
#endif // NOTHREADS

  auto end = std::chrono::steady_clock::now();
  auto duration =
      std::chrono::duration_cast<std::chrono::microseconds>(end - start);

  Stats stats(0);
  for (const auto &w : workers) {
    const auto &s = w->stats;

    stats.req_todo += s.req_todo;
    stats.req_started += s.req_started;
    stats.req_done += s.req_done;
    stats.req_timedout += s.req_timedout;
    stats.req_success += s.req_success;
    stats.req_status_success += s.req_status_success;
    stats.req_failed += s.req_failed;
    stats.req_error += s.req_error;
    stats.bytes_total += s.bytes_total;
    stats.bytes_head += s.bytes_head;
    stats.bytes_body += s.bytes_body;

    for (size_t i = 0; i < stats.status.size(); ++i) {
      stats.status[i] += s.status[i];
    }
  }

  auto ts = process_time_stats(workers);

  // Requests which have not been issued due to connection errors, are
  // counted towards req_failed and req_error.
  auto req_not_issued =
      stats.req_todo - stats.req_status_success - stats.req_failed;
  stats.req_failed += req_not_issued;
  stats.req_error += req_not_issued;

  // UI is heavily inspired by weighttp[1] and wrk[2]
  //
  // [1] https://github.com/lighttpd/weighttp
  // [2] https://github.com/wg/wrk
  double rps = 0;
  int64_t bps = 0;
  if (duration.count() > 0) {
    auto secd = std::chrono::duration_cast<
        std::chrono::duration<double, std::chrono::seconds::period>>(duration);
    rps = stats.req_success / secd.count();
    bps = stats.bytes_total / secd.count();
  }

  std::cout << R"(
finished in )" << util::format_duration(duration) << ", " << rps << " req/s, "
            << util::utos_with_funit(bps) << R"(B/s
requests: )" << stats.req_todo << " total, " << stats.req_started
            << " started, " << stats.req_done << " done, "
            << stats.req_status_success << " succeeded, " << stats.req_failed
            << " failed, " << stats.req_error << " errored, "
            << stats.req_timedout << R"( timeout
status codes: )" << stats.status[2] << " 2xx, " << stats.status[3] << " 3xx, "
            << stats.status[4] << " 4xx, " << stats.status[5] << R"( 5xx
traffic: )" << stats.bytes_total << " bytes total, " << stats.bytes_head
            << " bytes headers, " << stats.bytes_body << R"( bytes data
                     min         max         mean         sd        +/- sd
time for request: )" << std::setw(10) << util::format_duration(ts.request.min)
            << "  " << std::setw(10) << util::format_duration(ts.request.max)
            << "  " << std::setw(10) << util::format_duration(ts.request.mean)
            << "  " << std::setw(10) << util::format_duration(ts.request.sd)
            << std::setw(9) << util::dtos(ts.request.within_sd) << "%"
            << "\ntime for connect: " << std::setw(10)
            << util::format_duration(ts.connect.min) << "  " << std::setw(10)
            << util::format_duration(ts.connect.max) << "  " << std::setw(10)
            << util::format_duration(ts.connect.mean) << "  " << std::setw(10)
            << util::format_duration(ts.connect.sd) << std::setw(9)
            << util::dtos(ts.connect.within_sd) << "%"
            << "\ntime to 1st byte: " << std::setw(10)
            << util::format_duration(ts.ttfb.min) << "  " << std::setw(10)
            << util::format_duration(ts.ttfb.max) << "  " << std::setw(10)
            << util::format_duration(ts.ttfb.mean) << "  " << std::setw(10)
            << util::format_duration(ts.ttfb.sd) << std::setw(9)
            << util::dtos(ts.ttfb.within_sd) << "%" << std::endl;

  SSL_CTX_free(ssl_ctx);

  return 0;
}

} // namespace h2load

int main(int argc, char **argv) { return h2load::main(argc, argv); }