/*
 * nghttp2 - HTTP/2 C Library
 *
 * Copyright (c) 2012 Tatsuhiro Tsujikawa
 *
 * Permission is hereby granted, free of charge, to any person obtaining
 * a copy of this software and associated documentation files (the
 * "Software"), to deal in the Software without restriction, including
 * without limitation the rights to use, copy, modify, merge, publish,
 * distribute, sublicense, and/or sell copies of the Software, and to
 * permit persons to whom the Software is furnished to do so, subject to
 * the following conditions:
 *
 * The above copyright notice and this permission notice shall be
 * included in all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
 * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
 * OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
 * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 */
#include "shrpx_config.h"

#ifdef HAVE_PWD_H
#  include <pwd.h>
#endif // HAVE_PWD_H
#ifdef HAVE_NETDB_H
#  include <netdb.h>
#endif // HAVE_NETDB_H
#ifdef HAVE_SYSLOG_H
#  include <syslog.h>
#endif // HAVE_SYSLOG_H
#include <sys/types.h>
#include <sys/stat.h>
#ifdef HAVE_FCNTL_H
#  include <fcntl.h>
#endif // HAVE_FCNTL_H
#ifdef HAVE_UNISTD_H
#  include <unistd.h>
#endif // HAVE_UNISTD_H
#include <dirent.h>

#include <cstring>
#include <cerrno>
#include <limits>
#include <fstream>
#include <unordered_map>

#include <openssl/evp.h>

#include <nghttp2/nghttp2.h>

#include "url-parser/url_parser.h"

#include "shrpx_log.h"
#include "shrpx_tls.h"
#include "shrpx_http.h"
#ifdef HAVE_MRUBY
#  include "shrpx_mruby.h"
#endif // HAVE_MRUBY
#include "util.h"
#include "base64.h"
#include "ssl_compat.h"
#include "xsi_strerror.h"

#ifndef AI_NUMERICSERV
#  define AI_NUMERICSERV 0
#endif

namespace shrpx {

namespace {
Config *config;
} // namespace

constexpr auto SHRPX_UNIX_PATH_PREFIX = "unix:"_sr;

const Config *get_config() { return config; }

Config *mod_config() { return config; }

std::unique_ptr<Config> replace_config(std::unique_ptr<Config> another) {
  auto p = config;
  config = another.release();
  return std::unique_ptr<Config>(p);
}

void create_config() { config = new Config(); }

Config::~Config() {
  auto &upstreamconf = http2.upstream;

  nghttp2_option_del(upstreamconf.option);
  nghttp2_option_del(upstreamconf.alt_mode_option);
  nghttp2_session_callbacks_del(upstreamconf.callbacks);

  auto &downstreamconf = http2.downstream;

  nghttp2_option_del(downstreamconf.option);
  nghttp2_session_callbacks_del(downstreamconf.callbacks);

  auto &dumpconf = http2.upstream.debug.dump;

  if (dumpconf.request_header) {
    fclose(dumpconf.request_header);
  }

  if (dumpconf.response_header) {
    fclose(dumpconf.response_header);
  }
}

TicketKeys::~TicketKeys() {
  /* Erase keys from memory */
  for (auto &key : keys) {
    memset(&key, 0, sizeof(key));
  }
}

namespace {
int split_host_port(char *host, size_t hostlen, uint16_t *port_ptr,
                    const StringRef &hostport, const StringRef &opt) {
  // host and port in |hostport| is separated by single ','.
  auto sep = std::find(std::begin(hostport), std::end(hostport), ',');
  if (sep == std::end(hostport)) {
    LOG(ERROR) << opt << ": Invalid host, port: " << hostport;
    return -1;
  }
  size_t len = sep - std::begin(hostport);
  if (hostlen < len + 1) {
    LOG(ERROR) << opt << ": Hostname too long: " << hostport;
    return -1;
  }
  std::copy(std::begin(hostport), sep, host);
  host[len] = '\0';

  auto portstr = StringRef{sep + 1, std::end(hostport)};
  auto d = util::parse_uint(portstr);
  if (d && 1 <= d && d <= std::numeric_limits<uint16_t>::max()) {
    *port_ptr = *d;
    return 0;
  }

  LOG(ERROR) << opt << ": Port is invalid: " << portstr;
  return -1;
}
} // namespace

namespace {
bool is_secure(const StringRef &filename) {
  struct stat buf;
  int rv = stat(filename.data(), &buf);
  if (rv == 0) {
    if ((buf.st_mode & S_IRWXU) && !(buf.st_mode & S_IRWXG) &&
        !(buf.st_mode & S_IRWXO)) {
      return true;
    }
  }

  return false;
}
} // namespace

std::unique_ptr<TicketKeys>
read_tls_ticket_key_file(const std::vector<StringRef> &files,
                         const EVP_CIPHER *cipher, const EVP_MD *hmac) {
  auto ticket_keys = std::make_unique<TicketKeys>();
  auto &keys = ticket_keys->keys;
  keys.resize(files.size());
  auto enc_keylen = EVP_CIPHER_key_length(cipher);
  auto hmac_keylen = EVP_MD_size(hmac);
  if (cipher == EVP_aes_128_cbc()) {
    // backward compatibility, as a legacy of using same file format
    // with nginx and apache.
    hmac_keylen = 16;
  }
  auto expectedlen = keys[0].data.name.size() + enc_keylen + hmac_keylen;
  char buf[256];
  assert(sizeof(buf) >= expectedlen);

  size_t i = 0;
  for (auto &file : files) {
    struct stat fst {};

    if (stat(file.data(), &fst) == -1) {
      auto error = errno;
      LOG(ERROR) << "tls-ticket-key-file: could not stat file " << file
                 << ", errno=" << error;
      return nullptr;
    }

    if (static_cast<size_t>(fst.st_size) != expectedlen) {
      LOG(ERROR) << "tls-ticket-key-file: the expected file size is "
                 << expectedlen << ", the actual file size is " << fst.st_size;
      return nullptr;
    }

    std::ifstream f(file.data());
    if (!f) {
      LOG(ERROR) << "tls-ticket-key-file: could not open file " << file;
      return nullptr;
    }

    f.read(buf, expectedlen);
    if (static_cast<size_t>(f.gcount()) != expectedlen) {
      LOG(ERROR) << "tls-ticket-key-file: want to read " << expectedlen
                 << " bytes but only read " << f.gcount() << " bytes from "
                 << file;
      return nullptr;
    }

    auto &key = keys[i++];
    key.cipher = cipher;
    key.hmac = hmac;
    key.hmac_keylen = hmac_keylen;

    if (LOG_ENABLED(INFO)) {
      LOG(INFO) << "enc_keylen=" << enc_keylen
                << ", hmac_keylen=" << key.hmac_keylen;
    }

    auto p = buf;
    std::copy_n(p, key.data.name.size(), std::begin(key.data.name));
    p += key.data.name.size();
    std::copy_n(p, enc_keylen, std::begin(key.data.enc_key));
    p += enc_keylen;
    std::copy_n(p, hmac_keylen, std::begin(key.data.hmac_key));

    if (LOG_ENABLED(INFO)) {
      LOG(INFO) << "session ticket key: " << util::format_hex(key.data.name);
    }
  }
  return ticket_keys;
}

#ifdef ENABLE_HTTP3
std::shared_ptr<QUICKeyingMaterials>
read_quic_secret_file(const StringRef &path) {
  constexpr size_t expectedlen =
      SHRPX_QUIC_SECRET_RESERVEDLEN + SHRPX_QUIC_SECRETLEN + SHRPX_QUIC_SALTLEN;

  auto qkms = std::make_shared<QUICKeyingMaterials>();
  auto &kms = qkms->keying_materials;

  std::ifstream f(path.data());
  if (!f) {
    LOG(ERROR) << "frontend-quic-secret-file: could not open file " << path;
    return nullptr;
  }

  std::array<char, 4096> buf;

  while (f.getline(buf.data(), buf.size())) {
    auto len = strlen(buf.data());
    if (len == 0 || buf[0] == '#') {
      continue;
    }

    auto s = StringRef{std::begin(buf), std::begin(buf) + len};
    if (s.size() != expectedlen * 2 || !util::is_hex_string(s)) {
      LOG(ERROR) << "frontend-quic-secret-file: each line must be a "
                 << expectedlen * 2 << " bytes hex encoded string";
      return nullptr;
    }

    kms.emplace_back();
    auto &qkm = kms.back();

    auto p = std::begin(s);

    util::decode_hex(std::begin(qkm.reserved),
                     StringRef{p, p + qkm.reserved.size()});
    p += qkm.reserved.size() * 2;
    util::decode_hex(std::begin(qkm.secret),
                     StringRef{p, p + qkm.secret.size()});
    p += qkm.secret.size() * 2;
    util::decode_hex(std::begin(qkm.salt), StringRef{p, p + qkm.salt.size()});
    p += qkm.salt.size() * 2;

    assert(static_cast<size_t>(p - std::begin(s)) == expectedlen * 2);

    qkm.id = qkm.reserved[0] & SHRPX_QUIC_DCID_KM_ID_MASK;

    if (kms.size() == 8) {
      break;
    }
  }

  if (f.bad() || (!f.eof() && f.fail())) {
    LOG(ERROR)
        << "frontend-quic-secret-file: error occurred while reading file "
        << path;
    return nullptr;
  }

  if (kms.empty()) {
    LOG(WARN)
        << "frontend-quic-secret-file: no keying materials are present in file "
        << path;
    return nullptr;
  }

  return qkms;
}
#endif // ENABLE_HTTP3

FILE *open_file_for_write(const char *filename) {
  std::array<char, STRERROR_BUFSIZE> errbuf;

#ifdef O_CLOEXEC
  auto fd = open(filename, O_WRONLY | O_CLOEXEC | O_CREAT | O_TRUNC,
                 S_IRUSR | S_IWUSR);
#else
  auto fd = open(filename, O_WRONLY | O_CREAT | O_TRUNC, S_IRUSR | S_IWUSR);

  // We get race condition if execve is called at the same time.
  if (fd != -1) {
    util::make_socket_closeonexec(fd);
  }
#endif
  if (fd == -1) {
    auto error = errno;
    LOG(ERROR) << "Failed to open " << filename << " for writing. Cause: "
               << xsi_strerror(error, errbuf.data(), errbuf.size());
    return nullptr;
  }
  auto f = fdopen(fd, "wb");
  if (f == nullptr) {
    auto error = errno;
    LOG(ERROR) << "Failed to open " << filename << " for writing. Cause: "
               << xsi_strerror(error, errbuf.data(), errbuf.size());
    return nullptr;
  }

  return f;
}

namespace {
// Read passwd from |filename|
std::string read_passwd_from_file(const StringRef &opt,
                                  const StringRef &filename) {
  std::string line;

  if (!is_secure(filename)) {
    LOG(ERROR) << opt << ": Private key passwd file " << filename
               << " has insecure mode.";
    return line;
  }

  std::ifstream in(filename.data(), std::ios::binary);
  if (!in) {
    LOG(ERROR) << opt << ": Could not open key passwd file " << filename;
    return line;
  }

  std::getline(in, line);
  return line;
}
} // namespace

HeaderRefs::value_type parse_header(BlockAllocator &balloc,
                                    const StringRef &optarg) {
  auto colon = std::find(std::begin(optarg), std::end(optarg), ':');

  if (colon == std::end(optarg) || colon == std::begin(optarg)) {
    return {};
  }

  auto value = colon + 1;
  for (; *value == '\t' || *value == ' '; ++value)
    ;

  auto name_iov =
      make_byte_ref(balloc, std::distance(std::begin(optarg), colon) + 1);
  auto p = std::copy(std::begin(optarg), colon, std::begin(name_iov));
  util::inp_strlower(std::begin(name_iov), p);
  *p = '\0';

  auto nv =
      HeaderRef(StringRef{std::span{std::begin(name_iov), p}},
                make_string_ref(balloc, StringRef{value, std::end(optarg)}));

  if (!nghttp2_check_header_name(nv.name.byte(), nv.name.size()) ||
      !nghttp2_check_header_value_rfc9113(nv.value.byte(), nv.value.size())) {
    return {};
  }

  return nv;
}

template <typename T>
int parse_uint(T *dest, const StringRef &opt, const StringRef &optarg) {
  auto val = util::parse_uint(optarg);
  if (!val) {
    LOG(ERROR) << opt << ": bad value.  Specify an integer >= 0.";
    return -1;
  }

  *dest = *val;

  return 0;
}

namespace {
template <typename T>
int parse_uint_with_unit(T *dest, const StringRef &opt,
                         const StringRef &optarg) {
  auto n = util::parse_uint_with_unit(optarg);
  if (!n) {
    LOG(ERROR) << opt << ": bad value: '" << optarg << "'";
    return -1;
  }

  if (static_cast<uint64_t>(std::numeric_limits<T>::max()) <
      static_cast<uint64_t>(*n)) {
    LOG(ERROR) << opt
               << ": too large.  The value should be less than or equal to "
               << std::numeric_limits<T>::max();
    return -1;
  }

  *dest = *n;

  return 0;
}
} // namespace

namespace {
int parse_altsvc(AltSvc &altsvc, const StringRef &opt,
                 const StringRef &optarg) {
  // PROTOID, PORT, HOST, ORIGIN, PARAMS.
  auto tokens = util::split_str(optarg, ',', 5);

  if (tokens.size() < 2) {
    // Requires at least protocol_id and port
    LOG(ERROR) << opt << ": too few parameters: " << optarg;
    return -1;
  }

  int port;

  if (parse_uint(&port, opt, tokens[1]) != 0) {
    return -1;
  }

  if (port < 1 ||
      port > static_cast<int>(std::numeric_limits<uint16_t>::max())) {
    LOG(ERROR) << opt << ": port is invalid: " << tokens[1];
    return -1;
  }

  altsvc.protocol_id = make_string_ref(config->balloc, tokens[0]);

  altsvc.port = port;
  altsvc.service = make_string_ref(config->balloc, tokens[1]);

  if (tokens.size() > 2) {
    if (!tokens[2].empty()) {
      altsvc.host = make_string_ref(config->balloc, tokens[2]);
    }

    if (tokens.size() > 3) {
      if (!tokens[3].empty()) {
        altsvc.origin = make_string_ref(config->balloc, tokens[3]);
      }

      if (tokens.size() > 4) {
        if (!tokens[4].empty()) {
          altsvc.params = make_string_ref(config->balloc, tokens[4]);
        }
      }
    }
  }

  return 0;
}
} // namespace

namespace {
// generated by gennghttpxfun.py
LogFragmentType log_var_lookup_token(const StringRef &name) {
  switch (name.size()) {
  case 3:
    switch (name[2]) {
    case 'd':
      if (util::strieq("pi"_sr, name, 2)) {
        return LogFragmentType::PID;
      }
      break;
    }
    break;
  case 4:
    switch (name[3]) {
    case 'h':
      if (util::strieq("pat"_sr, name, 3)) {
        return LogFragmentType::PATH;
      }
      break;
    case 'n':
      if (util::strieq("alp"_sr, name, 3)) {
        return LogFragmentType::ALPN;
      }
      break;
    }
    break;
  case 6:
    switch (name[5]) {
    case 'd':
      if (util::strieq("metho"_sr, name, 5)) {
        return LogFragmentType::METHOD;
      }
      break;
    case 's':
      if (util::strieq("statu"_sr, name, 5)) {
        return LogFragmentType::STATUS;
      }
      break;
    }
    break;
  case 7:
    switch (name[6]) {
    case 'i':
      if (util::strieq("tls_sn"_sr, name, 6)) {
        return LogFragmentType::TLS_SNI;
      }
      break;
    case 't':
      if (util::strieq("reques"_sr, name, 6)) {
        return LogFragmentType::REQUEST;
      }
      break;
    }
    break;
  case 10:
    switch (name[9]) {
    case 'l':
      if (util::strieq("time_loca"_sr, name, 9)) {
        return LogFragmentType::TIME_LOCAL;
      }
      break;
    case 'r':
      if (util::strieq("ssl_ciphe"_sr, name, 9)) {
        return LogFragmentType::SSL_CIPHER;
      }
      if (util::strieq("tls_ciphe"_sr, name, 9)) {
        return LogFragmentType::TLS_CIPHER;
      }
      break;
    }
    break;
  case 11:
    switch (name[10]) {
    case 'r':
      if (util::strieq("remote_add"_sr, name, 10)) {
        return LogFragmentType::REMOTE_ADDR;
      }
      break;
    case 't':
      if (util::strieq("remote_por"_sr, name, 10)) {
        return LogFragmentType::REMOTE_PORT;
      }
      if (util::strieq("server_por"_sr, name, 10)) {
        return LogFragmentType::SERVER_PORT;
      }
      break;
    }
    break;
  case 12:
    switch (name[11]) {
    case '1':
      if (util::strieq("time_iso860"_sr, name, 11)) {
        return LogFragmentType::TIME_ISO8601;
      }
      break;
    case 'e':
      if (util::strieq("request_tim"_sr, name, 11)) {
        return LogFragmentType::REQUEST_TIME;
      }
      break;
    case 'l':
      if (util::strieq("ssl_protoco"_sr, name, 11)) {
        return LogFragmentType::SSL_PROTOCOL;
      }
      if (util::strieq("tls_protoco"_sr, name, 11)) {
        return LogFragmentType::TLS_PROTOCOL;
      }
      break;
    case 't':
      if (util::strieq("backend_hos"_sr, name, 11)) {
        return LogFragmentType::BACKEND_HOST;
      }
      if (util::strieq("backend_por"_sr, name, 11)) {
        return LogFragmentType::BACKEND_PORT;
      }
      break;
    }
    break;
  case 14:
    switch (name[13]) {
    case 'd':
      if (util::strieq("ssl_session_i"_sr, name, 13)) {
        return LogFragmentType::SSL_SESSION_ID;
      }
      if (util::strieq("tls_session_i"_sr, name, 13)) {
        return LogFragmentType::TLS_SESSION_ID;
      }
      break;
    }
    break;
  case 15:
    switch (name[14]) {
    case 't':
      if (util::strieq("body_bytes_sen"_sr, name, 14)) {
        return LogFragmentType::BODY_BYTES_SENT;
      }
      break;
    }
    break;
  case 16:
    switch (name[15]) {
    case 'n':
      if (util::strieq("protocol_versio"_sr, name, 15)) {
        return LogFragmentType::PROTOCOL_VERSION;
      }
      break;
    }
    break;
  case 17:
    switch (name[16]) {
    case 'l':
      if (util::strieq("tls_client_seria"_sr, name, 16)) {
        return LogFragmentType::TLS_CLIENT_SERIAL;
      }
      break;
    }
    break;
  case 18:
    switch (name[17]) {
    case 'd':
      if (util::strieq("ssl_session_reuse"_sr, name, 17)) {
        return LogFragmentType::SSL_SESSION_REUSED;
      }
      if (util::strieq("tls_session_reuse"_sr, name, 17)) {
        return LogFragmentType::TLS_SESSION_REUSED;
      }
      break;
    case 'y':
      if (util::strieq("path_without_quer"_sr, name, 17)) {
        return LogFragmentType::PATH_WITHOUT_QUERY;
      }
      break;
    }
    break;
  case 22:
    switch (name[21]) {
    case 'e':
      if (util::strieq("tls_client_issuer_nam"_sr, name, 21)) {
        return LogFragmentType::TLS_CLIENT_ISSUER_NAME;
      }
      break;
    }
    break;
  case 23:
    switch (name[22]) {
    case 'e':
      if (util::strieq("tls_client_subject_nam"_sr, name, 22)) {
        return LogFragmentType::TLS_CLIENT_SUBJECT_NAME;
      }
      break;
    }
    break;
  case 27:
    switch (name[26]) {
    case '1':
      if (util::strieq("tls_client_fingerprint_sha"_sr, name, 26)) {
        return LogFragmentType::TLS_CLIENT_FINGERPRINT_SHA1;
      }
      break;
    }
    break;
  case 29:
    switch (name[28]) {
    case '6':
      if (util::strieq("tls_client_fingerprint_sha25"_sr, name, 28)) {
        return LogFragmentType::TLS_CLIENT_FINGERPRINT_SHA256;
      }
      break;
    }
    break;
  }
  return LogFragmentType::NONE;
}
} // namespace

namespace {
bool var_token(char c) {
  return util::is_alpha(c) || util::is_digit(c) || c == '_';
}
} // namespace

std::vector<LogFragment> parse_log_format(BlockAllocator &balloc,
                                          const StringRef &optarg) {
  auto literal_start = std::begin(optarg);
  auto p = literal_start;
  auto eop = std::end(optarg);

  auto res = std::vector<LogFragment>();

  for (; p != eop;) {
    if (*p != '$') {
      ++p;
      continue;
    }

    auto var_start = p;

    ++p;

    StringRef var_name;
    if (p != eop && *p == '{') {
      auto var_name_start = ++p;
      for (; p != eop && var_token(*p); ++p)
        ;

      if (p == eop || *p != '}') {
        LOG(WARN) << "Missing '}' after " << StringRef{var_start, p};
        continue;
      }

      var_name = StringRef{var_name_start, p};
      ++p;
    } else {
      auto var_name_start = p;
      for (; p != eop && var_token(*p); ++p)
        ;

      var_name = StringRef{var_name_start, p};
    }

    auto value = std::begin(var_name);

    auto type = log_var_lookup_token(var_name);

    if (type == LogFragmentType::NONE) {
      if (util::istarts_with(var_name, "http_"_sr)) {
        if ("host"_sr == var_name.substr(str_size("http_"))) {
          // Special handling of host header field.  We will use
          // :authority header field if host header is missing.  This
          // is a typical case in HTTP/2.
          type = LogFragmentType::AUTHORITY;
        } else {
          type = LogFragmentType::HTTP;
          value += str_size("http_");
        }
      } else {
        LOG(WARN) << "Unrecognized log format variable: " << var_name;
        continue;
      }
    }

    if (literal_start < var_start) {
      res.emplace_back(
          LogFragmentType::LITERAL,
          make_string_ref(balloc, StringRef{literal_start, var_start}));
    }

    literal_start = p;

    if (value == std::begin(var_name)) {
      res.emplace_back(type);
      continue;
    }

    {
      auto iov =
          make_byte_ref(balloc, std::distance(value, std::end(var_name)) + 1);
      auto p = std::copy(value, std::end(var_name), std::begin(iov));
      std::transform(std::begin(iov), p, std::begin(iov),
                     [](auto c) { return c == '_' ? '-' : c; });
      *p = '\0';
      res.emplace_back(type, StringRef{std::span{std::begin(iov), p}});
    }
  }

  if (literal_start != eop) {
    res.emplace_back(LogFragmentType::LITERAL,
                     make_string_ref(balloc, StringRef{literal_start, eop}));
  }

  return res;
}

namespace {
int parse_address_family(int *dest, const StringRef &opt,
                         const StringRef &optarg) {
  if (util::strieq("auto"_sr, optarg)) {
    *dest = AF_UNSPEC;
    return 0;
  }
  if (util::strieq("IPv4"_sr, optarg)) {
    *dest = AF_INET;
    return 0;
  }
  if (util::strieq("IPv6"_sr, optarg)) {
    *dest = AF_INET6;
    return 0;
  }

  LOG(ERROR) << opt << ": bad value: '" << optarg << "'";
  return -1;
}
} // namespace

namespace {
int parse_duration(ev_tstamp *dest, const StringRef &opt,
                   const StringRef &optarg) {
  auto t = util::parse_duration_with_unit(optarg);
  if (!t) {
    LOG(ERROR) << opt << ": bad value: '" << optarg << "'";
    return -1;
  }

  *dest = *t;

  return 0;
}
} // namespace

namespace {
int parse_tls_proto_version(int &dest, const StringRef &opt,
                            const StringRef &optarg) {
  auto v = tls::proto_version_from_string(optarg);
  if (v == -1) {
    LOG(ERROR) << opt << ": invalid TLS protocol version: " << optarg;
    return -1;
  }

  dest = v;

  return 0;
}
} // namespace

struct MemcachedConnectionParams {
  bool tls;
};

namespace {
// Parses memcached connection configuration parameter |src_params|,
// and stores parsed results into |out|.  This function returns 0 if
// it succeeds, or -1.
int parse_memcached_connection_params(MemcachedConnectionParams &out,
                                      const StringRef &src_params,
                                      const StringRef &opt) {
  auto last = std::end(src_params);
  for (auto first = std::begin(src_params); first != last;) {
    auto end = std::find(first, last, ';');
    auto param = StringRef{first, end};

    if (util::strieq("tls"_sr, param)) {
      out.tls = true;
    } else if (util::strieq("no-tls"_sr, param)) {
      out.tls = false;
    } else if (!param.empty()) {
      LOG(ERROR) << opt << ": " << param << ": unknown keyword";
      return -1;
    }

    if (end == last) {
      break;
    }

    first = end + 1;
  }

  return 0;
}
} // namespace

struct UpstreamParams {
  UpstreamAltMode alt_mode;
  bool tls;
  bool sni_fwd;
  bool proxyproto;
  bool quic;
};

namespace {
// Parses upstream configuration parameter |src_params|, and stores
// parsed results into |out|.  This function returns 0 if it succeeds,
// or -1.
int parse_upstream_params(UpstreamParams &out, const StringRef &src_params) {
  auto last = std::end(src_params);
  for (auto first = std::begin(src_params); first != last;) {
    auto end = std::find(first, last, ';');
    auto param = StringRef{first, end};

    if (util::strieq("tls"_sr, param)) {
      out.tls = true;
    } else if (util::strieq("sni-fwd"_sr, param)) {
      out.sni_fwd = true;
    } else if (util::strieq("no-tls"_sr, param)) {
      out.tls = false;
    } else if (util::strieq("api"_sr, param)) {
      if (out.alt_mode != UpstreamAltMode::NONE &&
          out.alt_mode != UpstreamAltMode::API) {
        LOG(ERROR) << "frontend: api and healthmon are mutually exclusive";
        return -1;
      }
      out.alt_mode = UpstreamAltMode::API;
    } else if (util::strieq("healthmon"_sr, param)) {
      if (out.alt_mode != UpstreamAltMode::NONE &&
          out.alt_mode != UpstreamAltMode::HEALTHMON) {
        LOG(ERROR) << "frontend: api and healthmon are mutually exclusive";
        return -1;
      }
      out.alt_mode = UpstreamAltMode::HEALTHMON;
    } else if (util::strieq("proxyproto"_sr, param)) {
      out.proxyproto = true;
    } else if (util::strieq("quic"_sr, param)) {
#ifdef ENABLE_HTTP3
      out.quic = true;
#else  // !ENABLE_HTTP3
      LOG(ERROR) << "quic: QUIC is disabled at compile time";
      return -1;
#endif // !ENABLE_HTTP3
    } else if (!param.empty()) {
      LOG(ERROR) << "frontend: " << param << ": unknown keyword";
      return -1;
    }

    if (end == last) {
      break;
    }

    first = end + 1;
  }

  return 0;
}
} // namespace

struct DownstreamParams {
  StringRef sni;
  StringRef mruby;
  StringRef group;
  AffinityConfig affinity;
  ev_tstamp read_timeout;
  ev_tstamp write_timeout;
  size_t fall;
  size_t rise;
  uint32_t weight;
  uint32_t group_weight;
  Proto proto;
  bool tls;
  bool dns;
  bool redirect_if_not_tls;
  bool upgrade_scheme;
  bool dnf;
};

namespace {
// Parses |value| of parameter named |name| as duration.  This
// function returns 0 if it succeeds and the parsed value is assigned
// to |dest|, or -1.
int parse_downstream_param_duration(ev_tstamp &dest, const StringRef &name,
                                    const StringRef &value) {
  auto t = util::parse_duration_with_unit(value);
  if (!t) {
    LOG(ERROR) << "backend: " << name << ": bad value: '" << value << "'";
    return -1;
  }
  dest = *t;
  return 0;
}
} // namespace

namespace {
// Parses downstream configuration parameter |src_params|, and stores
// parsed results into |out|.  This function returns 0 if it succeeds,
// or -1.
int parse_downstream_params(DownstreamParams &out,
                            const StringRef &src_params) {
  auto last = std::end(src_params);
  for (auto first = std::begin(src_params); first != last;) {
    auto end = std::find(first, last, ';');
    auto param = StringRef{first, end};

    if (util::istarts_with(param, "proto="_sr)) {
      auto protostr = StringRef{first + str_size("proto="), end};
      if (protostr.empty()) {
        LOG(ERROR) << "backend: proto: protocol is empty";
        return -1;
      }

      if ("h2"_sr == protostr) {
        out.proto = Proto::HTTP2;
      } else if ("http/1.1"_sr == protostr) {
        out.proto = Proto::HTTP1;
      } else {
        LOG(ERROR) << "backend: proto: unknown protocol " << protostr;
        return -1;
      }
    } else if (util::istarts_with(param, "fall="_sr)) {
      auto valstr = StringRef{first + str_size("fall="), end};
      if (valstr.empty()) {
        LOG(ERROR) << "backend: fall: non-negative integer is expected";
        return -1;
      }

      auto n = util::parse_uint(valstr);
      if (!n) {
        LOG(ERROR) << "backend: fall: non-negative integer is expected";
        return -1;
      }

      out.fall = *n;
    } else if (util::istarts_with(param, "rise="_sr)) {
      auto valstr = StringRef{first + str_size("rise="), end};
      if (valstr.empty()) {
        LOG(ERROR) << "backend: rise: non-negative integer is expected";
        return -1;
      }

      auto n = util::parse_uint(valstr);
      if (!n) {
        LOG(ERROR) << "backend: rise: non-negative integer is expected";
        return -1;
      }

      out.rise = *n;
    } else if (util::strieq("tls"_sr, param)) {
      out.tls = true;
    } else if (util::strieq("no-tls"_sr, param)) {
      out.tls = false;
    } else if (util::istarts_with(param, "sni="_sr)) {
      out.sni = StringRef{first + str_size("sni="), end};
    } else if (util::istarts_with(param, "affinity="_sr)) {
      auto valstr = StringRef{first + str_size("affinity="), end};
      if (util::strieq("none"_sr, valstr)) {
        out.affinity.type = SessionAffinity::NONE;
      } else if (util::strieq("ip"_sr, valstr)) {
        out.affinity.type = SessionAffinity::IP;
      } else if (util::strieq("cookie"_sr, valstr)) {
        out.affinity.type = SessionAffinity::COOKIE;
      } else {
        LOG(ERROR)
            << "backend: affinity: value must be one of none, ip, and cookie";
        return -1;
      }
    } else if (util::istarts_with(param, "affinity-cookie-name="_sr)) {
      auto val = StringRef{first + str_size("affinity-cookie-name="), end};
      if (val.empty()) {
        LOG(ERROR)
            << "backend: affinity-cookie-name: non empty string is expected";
        return -1;
      }
      out.affinity.cookie.name = val;
    } else if (util::istarts_with(param, "affinity-cookie-path="_sr)) {
      out.affinity.cookie.path =
          StringRef{first + str_size("affinity-cookie-path="), end};
    } else if (util::istarts_with(param, "affinity-cookie-secure="_sr)) {
      auto valstr = StringRef{first + str_size("affinity-cookie-secure="), end};
      if (util::strieq("auto"_sr, valstr)) {
        out.affinity.cookie.secure = SessionAffinityCookieSecure::AUTO;
      } else if (util::strieq("yes"_sr, valstr)) {
        out.affinity.cookie.secure = SessionAffinityCookieSecure::YES;
      } else if (util::strieq("no"_sr, valstr)) {
        out.affinity.cookie.secure = SessionAffinityCookieSecure::NO;
      } else {
        LOG(ERROR) << "backend: affinity-cookie-secure: value must be one of "
                      "auto, yes, and no";
        return -1;
      }
    } else if (util::istarts_with(param, "affinity-cookie-stickiness="_sr)) {
      auto valstr =
          StringRef{first + str_size("affinity-cookie-stickiness="), end};
      if (util::strieq("loose"_sr, valstr)) {
        out.affinity.cookie.stickiness = SessionAffinityCookieStickiness::LOOSE;
      } else if (util::strieq("strict"_sr, valstr)) {
        out.affinity.cookie.stickiness =
            SessionAffinityCookieStickiness::STRICT;
      } else {
        LOG(ERROR) << "backend: affinity-cookie-stickiness: value must be "
                      "either loose or strict";
        return -1;
      }
    } else if (util::strieq("dns"_sr, param)) {
      out.dns = true;
    } else if (util::strieq("redirect-if-not-tls"_sr, param)) {
      out.redirect_if_not_tls = true;
    } else if (util::strieq("upgrade-scheme"_sr, param)) {
      out.upgrade_scheme = true;
    } else if (util::istarts_with(param, "mruby="_sr)) {
      auto valstr = StringRef{first + str_size("mruby="), end};
      out.mruby = valstr;
    } else if (util::istarts_with(param, "read-timeout="_sr)) {
      if (parse_downstream_param_duration(
              out.read_timeout, "read-timeout"_sr,
              StringRef{first + str_size("read-timeout="), end}) == -1) {
        return -1;
      }
    } else if (util::istarts_with(param, "write-timeout="_sr)) {
      if (parse_downstream_param_duration(
              out.write_timeout, "write-timeout"_sr,
              StringRef{first + str_size("write-timeout="), end}) == -1) {
        return -1;
      }
    } else if (util::istarts_with(param, "weight="_sr)) {
      auto valstr = StringRef{first + str_size("weight="), end};
      if (valstr.empty()) {
        LOG(ERROR)
            << "backend: weight: non-negative integer [1, 256] is expected";
        return -1;
      }

      auto n = util::parse_uint(valstr);
      if (!n || (n < 1 || n > 256)) {
        LOG(ERROR)
            << "backend: weight: non-negative integer [1, 256] is expected";
        return -1;
      }
      out.weight = *n;
    } else if (util::istarts_with(param, "group="_sr)) {
      auto valstr = StringRef{first + str_size("group="), end};
      if (valstr.empty()) {
        LOG(ERROR) << "backend: group: empty string is not allowed";
        return -1;
      }
      out.group = valstr;
    } else if (util::istarts_with(param, "group-weight="_sr)) {
      auto valstr = StringRef{first + str_size("group-weight="), end};
      if (valstr.empty()) {
        LOG(ERROR) << "backend: group-weight: non-negative integer [1, 256] is "
                      "expected";
        return -1;
      }

      auto n = util::parse_uint(valstr);
      if (!n || (n < 1 || n > 256)) {
        LOG(ERROR) << "backend: group-weight: non-negative integer [1, 256] is "
                      "expected";
        return -1;
      }
      out.group_weight = *n;
    } else if (util::strieq("dnf"_sr, param)) {
      out.dnf = true;
    } else if (!param.empty()) {
      LOG(ERROR) << "backend: " << param << ": unknown keyword";
      return -1;
    }

    if (end == last) {
      break;
    }

    first = end + 1;
  }

  return 0;
}
} // namespace

namespace {
// Parses host-path mapping patterns in |src_pattern|, and stores
// mappings in config.  We will store each host-path pattern found in
// |src| with |addr|.  |addr| will be copied accordingly.  Also we
// make a group based on the pattern.  The "/" pattern is considered
// as catch-all.  We also parse protocol specified in |src_proto|.
//
// This function returns 0 if it succeeds, or -1.
int parse_mapping(Config *config, DownstreamAddrConfig &addr,
                  std::map<StringRef, size_t> &pattern_addr_indexer,
                  const StringRef &src_pattern, const StringRef &src_params) {
  // This returns at least 1 element (it could be empty string).  We
  // will append '/' to all patterns, so it becomes catch-all pattern.
  auto mapping = util::split_str(src_pattern, ':');
  assert(!mapping.empty());
  auto &downstreamconf = *config->conn.downstream;
  auto &addr_groups = downstreamconf.addr_groups;

  DownstreamParams params{};
  params.proto = Proto::HTTP1;
  params.weight = 1;

  if (parse_downstream_params(params, src_params) != 0) {
    return -1;
  }

  if (addr.host_unix && params.dns) {
    LOG(ERROR) << "backend: dns: cannot be used for UNIX domain socket";
    return -1;
  }

  if (params.affinity.type == SessionAffinity::COOKIE &&
      params.affinity.cookie.name.empty()) {
    LOG(ERROR) << "backend: affinity-cookie-name is mandatory if "
                  "affinity=cookie is specified";
    return -1;
  }

  addr.fall = params.fall;
  addr.rise = params.rise;
  addr.weight = params.weight;
  addr.group = make_string_ref(downstreamconf.balloc, params.group);
  addr.group_weight = params.group_weight;
  addr.proto = params.proto;
  addr.tls = params.tls;
  addr.sni = make_string_ref(downstreamconf.balloc, params.sni);
  addr.dns = params.dns;
  addr.upgrade_scheme = params.upgrade_scheme;
  addr.dnf = params.dnf;

  auto &routerconf = downstreamconf.router;
  auto &router = routerconf.router;
  auto &rw_router = routerconf.rev_wildcard_router;
  auto &wildcard_patterns = routerconf.wildcard_patterns;

  for (const auto &raw_pattern : mapping) {
    StringRef pattern;
    auto slash = std::find(std::begin(raw_pattern), std::end(raw_pattern), '/');
    if (slash == std::end(raw_pattern)) {
      // This effectively makes empty pattern to "/".  2 for '/' and
      // terminal NULL character.
      auto iov = make_byte_ref(downstreamconf.balloc, raw_pattern.size() + 2);
      auto p = std::copy(std::begin(raw_pattern), std::end(raw_pattern),
                         std::begin(iov));
      util::inp_strlower(std::begin(iov), p);
      *p++ = '/';
      *p = '\0';
      pattern = StringRef{std::span{std::begin(iov), p}};
    } else {
      auto path = http2::normalize_path_colon(
          downstreamconf.balloc, StringRef{slash, std::end(raw_pattern)},
          StringRef{});
      auto iov = make_byte_ref(downstreamconf.balloc,
                               std::distance(std::begin(raw_pattern), slash) +
                                   path.size() + 1);
      auto p = std::copy(std::begin(raw_pattern), slash, std::begin(iov));
      util::inp_strlower(std::begin(iov), p);
      p = std::copy(std::begin(path), std::end(path), p);
      *p = '\0';
      pattern = StringRef{std::span{std::begin(iov), p}};
    }
    auto it = pattern_addr_indexer.find(pattern);
    if (it != std::end(pattern_addr_indexer)) {
      auto &g = addr_groups[(*it).second];
      // Last value wins if we have multiple different affinity
      // value under one group.
      if (params.affinity.type != SessionAffinity::NONE) {
        if (g.affinity.type == SessionAffinity::NONE) {
          g.affinity.type = params.affinity.type;
          if (params.affinity.type == SessionAffinity::COOKIE) {
            g.affinity.cookie.name = make_string_ref(
                downstreamconf.balloc, params.affinity.cookie.name);
            if (!params.affinity.cookie.path.empty()) {
              g.affinity.cookie.path = make_string_ref(
                  downstreamconf.balloc, params.affinity.cookie.path);
            }
            g.affinity.cookie.secure = params.affinity.cookie.secure;
            g.affinity.cookie.stickiness = params.affinity.cookie.stickiness;
          }
        } else if (g.affinity.type != params.affinity.type ||
                   g.affinity.cookie.name != params.affinity.cookie.name ||
                   g.affinity.cookie.path != params.affinity.cookie.path ||
                   g.affinity.cookie.secure != params.affinity.cookie.secure ||
                   g.affinity.cookie.stickiness !=
                       params.affinity.cookie.stickiness) {
          LOG(ERROR) << "backend: affinity: multiple different affinity "
                        "configurations found in a single group";
          return -1;
        }
      }
      // If at least one backend requires frontend TLS connection,
      // enable it for all backends sharing the same pattern.
      if (params.redirect_if_not_tls) {
        g.redirect_if_not_tls = true;
      }
      // All backends in the same group must have the same mruby path.
      // If some backends do not specify mruby file, and there is at
      // least one backend with mruby file, it is used for all
      // backends in the group.
      if (!params.mruby.empty()) {
        if (g.mruby_file.empty()) {
          g.mruby_file = make_string_ref(downstreamconf.balloc, params.mruby);
        } else if (g.mruby_file != params.mruby) {
          LOG(ERROR) << "backend: mruby: multiple different mruby file found "
                        "in a single group";
          return -1;
        }
      }
      // All backends in the same group must have the same read/write
      // timeout.  If some backends do not specify read/write timeout,
      // and there is at least one backend with read/write timeout, it
      // is used for all backends in the group.
      if (params.read_timeout > 1e-9) {
        if (g.timeout.read < 1e-9) {
          g.timeout.read = params.read_timeout;
        } else if (fabs(g.timeout.read - params.read_timeout) > 1e-9) {
          LOG(ERROR)
              << "backend: read-timeout: multiple different read-timeout "
                 "found in a single group";
          return -1;
        }
      }
      if (params.write_timeout > 1e-9) {
        if (g.timeout.write < 1e-9) {
          g.timeout.write = params.write_timeout;
        } else if (fabs(g.timeout.write - params.write_timeout) > 1e-9) {
          LOG(ERROR) << "backend: write-timeout: multiple different "
                        "write-timeout found in a single group";
          return -1;
        }
      }
      // All backends in the same group must have the same dnf
      // setting.  If some backends do not specify dnf, and there is
      // at least one backend with dnf, it is used for all backends in
      // the group.  In general, multiple backends are not necessary
      // for dnf because there is no need for load balancing.
      if (params.dnf) {
        g.dnf = true;
      }

      g.addrs.push_back(addr);
      continue;
    }

    auto idx = addr_groups.size();
    pattern_addr_indexer.emplace(pattern, idx);
    addr_groups.emplace_back(pattern);
    auto &g = addr_groups.back();
    g.addrs.push_back(addr);
    g.affinity.type = params.affinity.type;
    if (params.affinity.type == SessionAffinity::COOKIE) {
      g.affinity.cookie.name =
          make_string_ref(downstreamconf.balloc, params.affinity.cookie.name);
      if (!params.affinity.cookie.path.empty()) {
        g.affinity.cookie.path =
            make_string_ref(downstreamconf.balloc, params.affinity.cookie.path);
      }
      g.affinity.cookie.secure = params.affinity.cookie.secure;
      g.affinity.cookie.stickiness = params.affinity.cookie.stickiness;
    }
    g.redirect_if_not_tls = params.redirect_if_not_tls;
    g.mruby_file = make_string_ref(downstreamconf.balloc, params.mruby);
    g.timeout.read = params.read_timeout;
    g.timeout.write = params.write_timeout;
    g.dnf = params.dnf;

    if (pattern[0] == '*') {
      // wildcard pattern
      auto path_first =
          std::find(std::begin(g.pattern), std::end(g.pattern), '/');

      auto host = StringRef{std::begin(g.pattern) + 1, path_first};
      auto path = StringRef{path_first, std::end(g.pattern)};

      auto path_is_wildcard = false;
      if (path[path.size() - 1] == '*') {
        path = StringRef{std::begin(path), std::begin(path) + path.size() - 1};
        path_is_wildcard = true;
      }

      auto it = std::find_if(
          std::begin(wildcard_patterns), std::end(wildcard_patterns),
          [&host](const WildcardPattern &wp) { return wp.host == host; });

      if (it == std::end(wildcard_patterns)) {
        wildcard_patterns.emplace_back(host);

        auto &router = wildcard_patterns.back().router;
        router.add_route(path, idx, path_is_wildcard);

        auto iov = make_byte_ref(downstreamconf.balloc, host.size() + 1);
        auto p = std::reverse_copy(std::begin(host), std::end(host),
                                   std::begin(iov));
        *p = '\0';
        auto rev_host = StringRef{std::span{std::begin(iov), p}};

        rw_router.add_route(rev_host, wildcard_patterns.size() - 1);
      } else {
        (*it).router.add_route(path, idx, path_is_wildcard);
      }

      continue;
    }

    auto path_is_wildcard = false;
    if (pattern[pattern.size() - 1] == '*') {
      pattern = StringRef{std::begin(pattern),
                          std::begin(pattern) + pattern.size() - 1};
      path_is_wildcard = true;
    }

    router.add_route(pattern, idx, path_is_wildcard);
  }
  return 0;
}
} // namespace

namespace {
ForwardedNode parse_forwarded_node_type(const StringRef &optarg) {
  if (util::strieq("obfuscated"_sr, optarg)) {
    return ForwardedNode::OBFUSCATED;
  }

  if (util::strieq("ip"_sr, optarg)) {
    return ForwardedNode::IP;
  }

  if (optarg.size() < 2 || optarg[0] != '_') {
    return static_cast<ForwardedNode>(-1);
  }

  if (std::find_if_not(std::begin(optarg), std::end(optarg), [](char c) {
        return util::is_alpha(c) || util::is_digit(c) || c == '.' || c == '_' ||
               c == '-';
      }) != std::end(optarg)) {
    return static_cast<ForwardedNode>(-1);
  }

  return ForwardedNode::OBFUSCATED;
}
} // namespace

namespace {
int parse_error_page(std::vector<ErrorPage> &error_pages, const StringRef &opt,
                     const StringRef &optarg) {
  std::array<char, STRERROR_BUFSIZE> errbuf;

  auto eq = std::find(std::begin(optarg), std::end(optarg), '=');
  if (eq == std::end(optarg) || eq + 1 == std::end(optarg)) {
    LOG(ERROR) << opt << ": bad value: '" << optarg << "'";
    return -1;
  }

  auto codestr = StringRef{std::begin(optarg), eq};
  unsigned int code;

  if (codestr == "*"_sr) {
    code = 0;
  } else {
    auto n = util::parse_uint(codestr);

    if (!n || n < 400 || n > 599) {
      LOG(ERROR) << opt << ": bad code: '" << codestr << "'";
      return -1;
    }

    code = static_cast<unsigned int>(*n);
  }

  auto path = StringRef{eq + 1, std::end(optarg)};

  std::vector<uint8_t> content;
  auto fd = open(path.data(), O_RDONLY);
  if (fd == -1) {
    auto error = errno;
    LOG(ERROR) << opt << ": " << optarg << ": "
               << xsi_strerror(error, errbuf.data(), errbuf.size());
    return -1;
  }

  auto fd_closer = defer(close, fd);

  std::array<uint8_t, 4096> buf;
  for (;;) {
    auto n = read(fd, buf.data(), buf.size());
    if (n == -1) {
      auto error = errno;
      LOG(ERROR) << opt << ": " << optarg << ": "
                 << xsi_strerror(error, errbuf.data(), errbuf.size());
      return -1;
    }
    if (n == 0) {
      break;
    }
    content.insert(std::end(content), std::begin(buf), std::begin(buf) + n);
  }

  error_pages.push_back(ErrorPage{std::move(content), code});

  return 0;
}
} // namespace

namespace {
// Maximum size of SCT extension payload length.
constexpr size_t MAX_SCT_EXT_LEN = 16_k;
} // namespace

struct SubcertParams {
  StringRef sct_dir;
};

namespace {
// Parses subcert parameter |src_params|, and stores parsed results
// into |out|.  This function returns 0 if it succeeds, or -1.
int parse_subcert_params(SubcertParams &out, const StringRef &src_params) {
  auto last = std::end(src_params);
  for (auto first = std::begin(src_params); first != last;) {
    auto end = std::find(first, last, ';');
    auto param = StringRef{first, end};

    if (util::istarts_with(param, "sct-dir="_sr)) {
#if defined(NGHTTP2_GENUINE_OPENSSL) || defined(NGHTTP2_OPENSSL_IS_BORINGSSL)
      auto sct_dir =
          StringRef{std::begin(param) + str_size("sct-dir="), std::end(param)};
      if (sct_dir.empty()) {
        LOG(ERROR) << "subcert: " << param << ": empty sct-dir";
        return -1;
      }
      out.sct_dir = sct_dir;
#else  // !NGHTTP2_GENUINE_OPENSSL && !NGHTTP2_OPENSSL_IS_BORINGSSL
      LOG(WARN) << "subcert: sct-dir is ignored because underlying TLS library "
                   "does not support SCT";
#endif // !NGHTTP2_GENUINE_OPENSSL && !NGHTTP2_OPENSSL_IS_BORINGSSL
    } else if (!param.empty()) {
      LOG(ERROR) << "subcert: " << param << ": unknown keyword";
      return -1;
    }

    if (end == last) {
      break;
    }

    first = end + 1;
  }

  return 0;
}
} // namespace

namespace {
// Reads *.sct files from directory denoted by |dir_path|.  |dir_path|
// must be NULL-terminated string.
int read_tls_sct_from_dir(std::vector<uint8_t> &dst, const StringRef &opt,
                          const StringRef &dir_path) {
  std::array<char, STRERROR_BUFSIZE> errbuf;

  auto dir = opendir(dir_path.data());
  if (dir == nullptr) {
    auto error = errno;
    LOG(ERROR) << opt << ": " << dir_path << ": "
               << xsi_strerror(error, errbuf.data(), errbuf.size());
    return -1;
  }

  auto closer = defer(closedir, dir);

  // 2 bytes total length field
  auto len_idx = std::distance(std::begin(dst), std::end(dst));
  dst.insert(std::end(dst), 2, 0);

  for (;;) {
    errno = 0;
    auto ent = readdir(dir);
    if (ent == nullptr) {
      if (errno != 0) {
        auto error = errno;
        LOG(ERROR) << opt << ": failed to read directory " << dir_path << ": "
                   << xsi_strerror(error, errbuf.data(), errbuf.size());
        return -1;
      }
      break;
    }

    auto name = StringRef{ent->d_name};

    if (name[0] == '.' || !util::iends_with(name, ".sct"_sr)) {
      continue;
    }

    std::string path;
    path.resize(dir_path.size() + 1 + name.size());
    {
      auto p = std::begin(path);
      p = std::copy(std::begin(dir_path), std::end(dir_path), p);
      *p++ = '/';
      std::copy(std::begin(name), std::end(name), p);
    }

    auto fd = open(path.c_str(), O_RDONLY);
    if (fd == -1) {
      auto error = errno;
      LOG(ERROR) << opt << ": failed to read SCT from " << path << ": "
                 << xsi_strerror(error, errbuf.data(), errbuf.size());
      return -1;
    }

    auto closer = defer(close, fd);

    // 2 bytes length field for this SCT.
    auto len_idx = std::distance(std::begin(dst), std::end(dst));
    dst.insert(std::end(dst), 2, 0);

    // *.sct file tends to be small; around 110+ bytes.
    std::array<char, 256> buf;
    for (;;) {
      ssize_t nread;
      while ((nread = read(fd, buf.data(), buf.size())) == -1 && errno == EINTR)
        ;

      if (nread == -1) {
        auto error = errno;
        LOG(ERROR) << opt << ": failed to read SCT data from " << path << ": "
                   << xsi_strerror(error, errbuf.data(), errbuf.size());
        return -1;
      }

      if (nread == 0) {
        break;
      }

      dst.insert(std::end(dst), std::begin(buf), std::begin(buf) + nread);

      if (dst.size() > MAX_SCT_EXT_LEN) {
        LOG(ERROR) << opt << ": the concatenated SCT data from " << dir_path
                   << " is too large.  Max " << MAX_SCT_EXT_LEN;
        return -1;
      }
    }

    auto len = dst.size() - len_idx - 2;

    if (len == 0) {
      dst.resize(dst.size() - 2);
      continue;
    }

    dst[len_idx] = len >> 8;
    dst[len_idx + 1] = len;
  }

  auto len = dst.size() - len_idx - 2;

  if (len == 0) {
    dst.resize(dst.size() - 2);
    return 0;
  }

  dst[len_idx] = len >> 8;
  dst[len_idx + 1] = len;

  return 0;
}
} // namespace

#ifndef OPENSSL_NO_PSK
namespace {
// Reads PSK secrets from path, and parses each line.  The result is
// directly stored into config->tls.psk_secrets.  This function
// returns 0 if it succeeds, or -1.
int parse_psk_secrets(Config *config, const StringRef &path) {
  auto &tlsconf = config->tls;

  std::ifstream f(path.data(), std::ios::binary);
  if (!f) {
    LOG(ERROR) << SHRPX_OPT_PSK_SECRETS << ": could not open file " << path;
    return -1;
  }

  size_t lineno = 0;
  std::string line;
  while (std::getline(f, line)) {
    ++lineno;
    if (line.empty() || line[0] == '#') {
      continue;
    }

    auto sep_it = std::find(std::begin(line), std::end(line), ':');
    if (sep_it == std::end(line)) {
      LOG(ERROR) << SHRPX_OPT_PSK_SECRETS
                 << ": could not fine separator at line " << lineno;
      return -1;
    }

    if (sep_it == std::begin(line)) {
      LOG(ERROR) << SHRPX_OPT_PSK_SECRETS << ": empty identity at line "
                 << lineno;
      return -1;
    }

    if (sep_it + 1 == std::end(line)) {
      LOG(ERROR) << SHRPX_OPT_PSK_SECRETS << ": empty secret at line "
                 << lineno;
      return -1;
    }

    if (!util::is_hex_string(StringRef{sep_it + 1, std::end(line)})) {
      LOG(ERROR) << SHRPX_OPT_PSK_SECRETS
                 << ": secret must be hex string at line " << lineno;
      return -1;
    }

    auto identity =
        make_string_ref(config->balloc, StringRef{std::begin(line), sep_it});

    auto secret =
        util::decode_hex(config->balloc, StringRef{sep_it + 1, std::end(line)});

    auto rv = tlsconf.psk_secrets.emplace(identity, secret);
    if (!rv.second) {
      LOG(ERROR) << SHRPX_OPT_PSK_SECRETS
                 << ": identity has already been registered at line " << lineno;
      return -1;
    }
  }

  return 0;
}
} // namespace
#endif // !OPENSSL_NO_PSK

#ifndef OPENSSL_NO_PSK
namespace {
// Reads PSK secrets from path, and parses each line.  The result is
// directly stored into config->tls.client.psk.  This function returns
// 0 if it succeeds, or -1.
int parse_client_psk_secrets(Config *config, const StringRef &path) {
  auto &tlsconf = config->tls;

  std::ifstream f(path.data(), std::ios::binary);
  if (!f) {
    LOG(ERROR) << SHRPX_OPT_CLIENT_PSK_SECRETS << ": could not open file "
               << path;
    return -1;
  }

  size_t lineno = 0;
  std::string line;
  while (std::getline(f, line)) {
    ++lineno;
    if (line.empty() || line[0] == '#') {
      continue;
    }

    auto sep_it = std::find(std::begin(line), std::end(line), ':');
    if (sep_it == std::end(line)) {
      LOG(ERROR) << SHRPX_OPT_CLIENT_PSK_SECRETS
                 << ": could not find separator at line " << lineno;
      return -1;
    }

    if (sep_it == std::begin(line)) {
      LOG(ERROR) << SHRPX_OPT_CLIENT_PSK_SECRETS << ": empty identity at line "
                 << lineno;
      return -1;
    }

    if (sep_it + 1 == std::end(line)) {
      LOG(ERROR) << SHRPX_OPT_CLIENT_PSK_SECRETS << ": empty secret at line "
                 << lineno;
      return -1;
    }

    if (!util::is_hex_string(StringRef{sep_it + 1, std::end(line)})) {
      LOG(ERROR) << SHRPX_OPT_CLIENT_PSK_SECRETS
                 << ": secret must be hex string at line " << lineno;
      return -1;
    }

    tlsconf.client.psk.identity =
        make_string_ref(config->balloc, StringRef{std::begin(line), sep_it});

    tlsconf.client.psk.secret = StringRef{util::decode_hex(
        config->balloc, StringRef{sep_it + 1, std::end(line)})};

    return 0;
  }

  return 0;
}
} // namespace
#endif // !OPENSSL_NO_PSK

// generated by gennghttpxfun.py
int option_lookup_token(const StringRef &name) {
  switch (name.size()) {
  case 4:
    switch (name[3]) {
    case 'f':
      if (util::strieq("con"_sr, name, 3)) {
        return SHRPX_OPTID_CONF;
      }
      break;
    case 'r':
      if (util::strieq("use"_sr, name, 3)) {
        return SHRPX_OPTID_USER;
      }
      break;
    }
    break;
  case 6:
    switch (name[5]) {
    case 'a':
      if (util::strieq("no-vi"_sr, name, 5)) {
        return SHRPX_OPTID_NO_VIA;
      }
      break;
    case 'c':
      if (util::strieq("altsv"_sr, name, 5)) {
        return SHRPX_OPTID_ALTSVC;
      }
      break;
    case 'n':
      if (util::strieq("daemo"_sr, name, 5)) {
        return SHRPX_OPTID_DAEMON;
      }
      break;
    case 't':
      if (util::strieq("cacer"_sr, name, 5)) {
        return SHRPX_OPTID_CACERT;
      }
      if (util::strieq("clien"_sr, name, 5)) {
        return SHRPX_OPTID_CLIENT;
      }
      break;
    }
    break;
  case 7:
    switch (name[6]) {
    case 'd':
      if (util::strieq("backen"_sr, name, 6)) {
        return SHRPX_OPTID_BACKEND;
      }
      break;
    case 'e':
      if (util::strieq("includ"_sr, name, 6)) {
        return SHRPX_OPTID_INCLUDE;
      }
      break;
    case 'g':
      if (util::strieq("backlo"_sr, name, 6)) {
        return SHRPX_OPTID_BACKLOG;
      }
      if (util::strieq("paddin"_sr, name, 6)) {
        return SHRPX_OPTID_PADDING;
      }
      break;
    case 'p':
      if (util::strieq("no-ocs"_sr, name, 6)) {
        return SHRPX_OPTID_NO_OCSP;
      }
      break;
    case 's':
      if (util::strieq("cipher"_sr, name, 6)) {
        return SHRPX_OPTID_CIPHERS;
      }
      if (util::strieq("worker"_sr, name, 6)) {
        return SHRPX_OPTID_WORKERS;
      }
      break;
    case 't':
      if (util::strieq("subcer"_sr, name, 6)) {
        return SHRPX_OPTID_SUBCERT;
      }
      break;
    }
    break;
  case 8:
    switch (name[7]) {
    case 'd':
      if (util::strieq("fronten"_sr, name, 7)) {
        return SHRPX_OPTID_FRONTEND;
      }
      break;
    case 'e':
      if (util::strieq("insecur"_sr, name, 7)) {
        return SHRPX_OPTID_INSECURE;
      }
      if (util::strieq("pid-fil"_sr, name, 7)) {
        return SHRPX_OPTID_PID_FILE;
      }
      break;
    case 'n':
      if (util::strieq("fastope"_sr, name, 7)) {
        return SHRPX_OPTID_FASTOPEN;
      }
      break;
    case 's':
      if (util::strieq("tls-ktl"_sr, name, 7)) {
        return SHRPX_OPTID_TLS_KTLS;
      }
      break;
    case 't':
      if (util::strieq("npn-lis"_sr, name, 7)) {
        return SHRPX_OPTID_NPN_LIST;
      }
      break;
    }
    break;
  case 9:
    switch (name[8]) {
    case 'e':
      if (util::strieq("no-kqueu"_sr, name, 8)) {
        return SHRPX_OPTID_NO_KQUEUE;
      }
      if (util::strieq("read-rat"_sr, name, 8)) {
        return SHRPX_OPTID_READ_RATE;
      }
      break;
    case 'l':
      if (util::strieq("log-leve"_sr, name, 8)) {
        return SHRPX_OPTID_LOG_LEVEL;
      }
      break;
    case 't':
      if (util::strieq("alpn-lis"_sr, name, 8)) {
        return SHRPX_OPTID_ALPN_LIST;
      }
      break;
    }
    break;
  case 10:
    switch (name[9]) {
    case 'e':
      if (util::strieq("error-pag"_sr, name, 9)) {
        return SHRPX_OPTID_ERROR_PAGE;
      }
      if (util::strieq("mruby-fil"_sr, name, 9)) {
        return SHRPX_OPTID_MRUBY_FILE;
      }
      if (util::strieq("write-rat"_sr, name, 9)) {
        return SHRPX_OPTID_WRITE_RATE;
      }
      break;
    case 't':
      if (util::strieq("read-burs"_sr, name, 9)) {
        return SHRPX_OPTID_READ_BURST;
      }
      break;
    }
    break;
  case 11:
    switch (name[10]) {
    case 'e':
      if (util::strieq("server-nam"_sr, name, 10)) {
        return SHRPX_OPTID_SERVER_NAME;
      }
      break;
    case 'f':
      if (util::strieq("no-quic-bp"_sr, name, 10)) {
        return SHRPX_OPTID_NO_QUIC_BPF;
      }
      break;
    case 'r':
      if (util::strieq("tls-sct-di"_sr, name, 10)) {
        return SHRPX_OPTID_TLS_SCT_DIR;
      }
      break;
    case 's':
      if (util::strieq("backend-tl"_sr, name, 10)) {
        return SHRPX_OPTID_BACKEND_TLS;
      }
      if (util::strieq("ecdh-curve"_sr, name, 10)) {
        return SHRPX_OPTID_ECDH_CURVES;
      }
      if (util::strieq("psk-secret"_sr, name, 10)) {
        return SHRPX_OPTID_PSK_SECRETS;
      }
      break;
    case 't':
      if (util::strieq("write-burs"_sr, name, 10)) {
        return SHRPX_OPTID_WRITE_BURST;
      }
      break;
    case 'y':
      if (util::strieq("dns-max-tr"_sr, name, 10)) {
        return SHRPX_OPTID_DNS_MAX_TRY;
      }
      if (util::strieq("http2-prox"_sr, name, 10)) {
        return SHRPX_OPTID_HTTP2_PROXY;
      }
      break;
    }
    break;
  case 12:
    switch (name[11]) {
    case '4':
      if (util::strieq("backend-ipv"_sr, name, 11)) {
        return SHRPX_OPTID_BACKEND_IPV4;
      }
      break;
    case '6':
      if (util::strieq("backend-ipv"_sr, name, 11)) {
        return SHRPX_OPTID_BACKEND_IPV6;
      }
      break;
    case 'c':
      if (util::strieq("http2-altsv"_sr, name, 11)) {
        return SHRPX_OPTID_HTTP2_ALTSVC;
      }
      break;
    case 'e':
      if (util::strieq("host-rewrit"_sr, name, 11)) {
        return SHRPX_OPTID_HOST_REWRITE;
      }
      if (util::strieq("http2-bridg"_sr, name, 11)) {
        return SHRPX_OPTID_HTTP2_BRIDGE;
      }
      break;
    case 'p':
      if (util::strieq("ocsp-startu"_sr, name, 11)) {
        return SHRPX_OPTID_OCSP_STARTUP;
      }
      break;
    case 'y':
      if (util::strieq("client-prox"_sr, name, 11)) {
        return SHRPX_OPTID_CLIENT_PROXY;
      }
      if (util::strieq("forwarded-b"_sr, name, 11)) {
        return SHRPX_OPTID_FORWARDED_BY;
      }
      break;
    }
    break;
  case 13:
    switch (name[12]) {
    case 'd':
      if (util::strieq("add-forwarde"_sr, name, 12)) {
        return SHRPX_OPTID_ADD_FORWARDED;
      }
      if (util::strieq("single-threa"_sr, name, 12)) {
        return SHRPX_OPTID_SINGLE_THREAD;
      }
      break;
    case 'e':
      if (util::strieq("dh-param-fil"_sr, name, 12)) {
        return SHRPX_OPTID_DH_PARAM_FILE;
      }
      if (util::strieq("errorlog-fil"_sr, name, 12)) {
        return SHRPX_OPTID_ERRORLOG_FILE;
      }
      if (util::strieq("rlimit-nofil"_sr, name, 12)) {
        return SHRPX_OPTID_RLIMIT_NOFILE;
      }
      break;
    case 'r':
      if (util::strieq("forwarded-fo"_sr, name, 12)) {
        return SHRPX_OPTID_FORWARDED_FOR;
      }
      break;
    case 's':
      if (util::strieq("tls13-cipher"_sr, name, 12)) {
        return SHRPX_OPTID_TLS13_CIPHERS;
      }
      break;
    case 't':
      if (util::strieq("verify-clien"_sr, name, 12)) {
        return SHRPX_OPTID_VERIFY_CLIENT;
      }
      break;
    }
    break;
  case 14:
    switch (name[13]) {
    case 'd':
      if (util::strieq("quic-server-i"_sr, name, 13)) {
        return SHRPX_OPTID_QUIC_SERVER_ID;
      }
      break;
    case 'e':
      if (util::strieq("accesslog-fil"_sr, name, 13)) {
        return SHRPX_OPTID_ACCESSLOG_FILE;
      }
      break;
    case 'h':
      if (util::strieq("no-server-pus"_sr, name, 13)) {
        return SHRPX_OPTID_NO_SERVER_PUSH;
      }
      break;
    case 'k':
      if (util::strieq("rlimit-memloc"_sr, name, 13)) {
        return SHRPX_OPTID_RLIMIT_MEMLOCK;
      }
      break;
    case 'p':
      if (util::strieq("no-verify-ocs"_sr, name, 13)) {
        return SHRPX_OPTID_NO_VERIFY_OCSP;
      }
      break;
    case 's':
      if (util::strieq("backend-no-tl"_sr, name, 13)) {
        return SHRPX_OPTID_BACKEND_NO_TLS;
      }
      if (util::strieq("client-cipher"_sr, name, 13)) {
        return SHRPX_OPTID_CLIENT_CIPHERS;
      }
      if (util::strieq("single-proces"_sr, name, 13)) {
        return SHRPX_OPTID_SINGLE_PROCESS;
      }
      break;
    case 't':
      if (util::strieq("tls-proto-lis"_sr, name, 13)) {
        return SHRPX_OPTID_TLS_PROTO_LIST;
      }
      break;
    }
    break;
  case 15:
    switch (name[14]) {
    case 'e':
      if (util::strieq("no-host-rewrit"_sr, name, 14)) {
        return SHRPX_OPTID_NO_HOST_REWRITE;
      }
      break;
    case 'g':
      if (util::strieq("errorlog-syslo"_sr, name, 14)) {
        return SHRPX_OPTID_ERRORLOG_SYSLOG;
      }
      break;
    case 's':
      if (util::strieq("frontend-no-tl"_sr, name, 14)) {
        return SHRPX_OPTID_FRONTEND_NO_TLS;
      }
      break;
    case 'y':
      if (util::strieq("syslog-facilit"_sr, name, 14)) {
        return SHRPX_OPTID_SYSLOG_FACILITY;
      }
      break;
    }
    break;
  case 16:
    switch (name[15]) {
    case 'e':
      if (util::strieq("certificate-fil"_sr, name, 15)) {
        return SHRPX_OPTID_CERTIFICATE_FILE;
      }
      if (util::strieq("client-cert-fil"_sr, name, 15)) {
        return SHRPX_OPTID_CLIENT_CERT_FILE;
      }
      if (util::strieq("private-key-fil"_sr, name, 15)) {
        return SHRPX_OPTID_PRIVATE_KEY_FILE;
      }
      if (util::strieq("worker-read-rat"_sr, name, 15)) {
        return SHRPX_OPTID_WORKER_READ_RATE;
      }
      break;
    case 'g':
      if (util::strieq("accesslog-syslo"_sr, name, 15)) {
        return SHRPX_OPTID_ACCESSLOG_SYSLOG;
      }
      break;
    case 't':
      if (util::strieq("accesslog-forma"_sr, name, 15)) {
        return SHRPX_OPTID_ACCESSLOG_FORMAT;
      }
      break;
    }
    break;
  case 17:
    switch (name[16]) {
    case 'e':
      if (util::strieq("no-server-rewrit"_sr, name, 16)) {
        return SHRPX_OPTID_NO_SERVER_REWRITE;
      }
      if (util::strieq("worker-write-rat"_sr, name, 16)) {
        return SHRPX_OPTID_WORKER_WRITE_RATE;
      }
      break;
    case 's':
      if (util::strieq("backend-http1-tl"_sr, name, 16)) {
        return SHRPX_OPTID_BACKEND_HTTP1_TLS;
      }
      if (util::strieq("max-header-field"_sr, name, 16)) {
        return SHRPX_OPTID_MAX_HEADER_FIELDS;
      }
      break;
    case 't':
      if (util::strieq("dns-cache-timeou"_sr, name, 16)) {
        return SHRPX_OPTID_DNS_CACHE_TIMEOUT;
      }
      if (util::strieq("worker-read-burs"_sr, name, 16)) {
        return SHRPX_OPTID_WORKER_READ_BURST;
      }
      break;
    }
    break;
  case 18:
    switch (name[17]) {
    case 'a':
      if (util::strieq("tls-max-early-dat"_sr, name, 17)) {
        return SHRPX_OPTID_TLS_MAX_EARLY_DATA;
      }
      break;
    case 'r':
      if (util::strieq("add-request-heade"_sr, name, 17)) {
        return SHRPX_OPTID_ADD_REQUEST_HEADER;
      }
      break;
    case 's':
      if (util::strieq("client-psk-secret"_sr, name, 17)) {
        return SHRPX_OPTID_CLIENT_PSK_SECRETS;
      }
      break;
    case 't':
      if (util::strieq("dns-lookup-timeou"_sr, name, 17)) {
        return SHRPX_OPTID_DNS_LOOKUP_TIMEOUT;
      }
      if (util::strieq("worker-write-burs"_sr, name, 17)) {
        return SHRPX_OPTID_WORKER_WRITE_BURST;
      }
      break;
    }
    break;
  case 19:
    switch (name[18]) {
    case 'e':
      if (util::strieq("no-location-rewrit"_sr, name, 18)) {
        return SHRPX_OPTID_NO_LOCATION_REWRITE;
      }
      if (util::strieq("require-http-schem"_sr, name, 18)) {
        return SHRPX_OPTID_REQUIRE_HTTP_SCHEME;
      }
      if (util::strieq("tls-ticket-key-fil"_sr, name, 18)) {
        return SHRPX_OPTID_TLS_TICKET_KEY_FILE;
      }
      break;
    case 'f':
      if (util::strieq("backend-max-backof"_sr, name, 18)) {
        return SHRPX_OPTID_BACKEND_MAX_BACKOFF;
      }
      break;
    case 'r':
      if (util::strieq("add-response-heade"_sr, name, 18)) {
        return SHRPX_OPTID_ADD_RESPONSE_HEADER;
      }
      if (util::strieq("add-x-forwarded-fo"_sr, name, 18)) {
        return SHRPX_OPTID_ADD_X_FORWARDED_FOR;
      }
      if (util::strieq("header-field-buffe"_sr, name, 18)) {
        return SHRPX_OPTID_HEADER_FIELD_BUFFER;
      }
      break;
    case 't':
      if (util::strieq("redirect-https-por"_sr, name, 18)) {
        return SHRPX_OPTID_REDIRECT_HTTPS_PORT;
      }
      if (util::strieq("stream-read-timeou"_sr, name, 18)) {
        return SHRPX_OPTID_STREAM_READ_TIMEOUT;
      }
      break;
    }
    break;
  case 20:
    switch (name[19]) {
    case 'g':
      if (util::strieq("frontend-frame-debu"_sr, name, 19)) {
        return SHRPX_OPTID_FRONTEND_FRAME_DEBUG;
      }
      break;
    case 'l':
      if (util::strieq("ocsp-update-interva"_sr, name, 19)) {
        return SHRPX_OPTID_OCSP_UPDATE_INTERVAL;
      }
      break;
    case 's':
      if (util::strieq("max-worker-processe"_sr, name, 19)) {
        return SHRPX_OPTID_MAX_WORKER_PROCESSES;
      }
      if (util::strieq("tls13-client-cipher"_sr, name, 19)) {
        return SHRPX_OPTID_TLS13_CLIENT_CIPHERS;
      }
      break;
    case 't':
      if (util::strieq("backend-read-timeou"_sr, name, 19)) {
        return SHRPX_OPTID_BACKEND_READ_TIMEOUT;
      }
      if (util::strieq("stream-write-timeou"_sr, name, 19)) {
        return SHRPX_OPTID_STREAM_WRITE_TIMEOUT;
      }
      if (util::strieq("verify-client-cacer"_sr, name, 19)) {
        return SHRPX_OPTID_VERIFY_CLIENT_CACERT;
      }
      break;
    case 'y':
      if (util::strieq("api-max-request-bod"_sr, name, 19)) {
        return SHRPX_OPTID_API_MAX_REQUEST_BODY;
      }
      break;
    }
    break;
  case 21:
    switch (name[20]) {
    case 'd':
      if (util::strieq("backend-tls-sni-fiel"_sr, name, 20)) {
        return SHRPX_OPTID_BACKEND_TLS_SNI_FIELD;
      }
      break;
    case 'e':
      if (util::strieq("quic-bpf-program-fil"_sr, name, 20)) {
        return SHRPX_OPTID_QUIC_BPF_PROGRAM_FILE;
      }
      break;
    case 'l':
      if (util::strieq("accept-proxy-protoco"_sr, name, 20)) {
        return SHRPX_OPTID_ACCEPT_PROXY_PROTOCOL;
      }
      break;
    case 'n':
      if (util::strieq("tls-max-proto-versio"_sr, name, 20)) {
        return SHRPX_OPTID_TLS_MAX_PROTO_VERSION;
      }
      if (util::strieq("tls-min-proto-versio"_sr, name, 20)) {
        return SHRPX_OPTID_TLS_MIN_PROTO_VERSION;
      }
      break;
    case 'r':
      if (util::strieq("tls-ticket-key-ciphe"_sr, name, 20)) {
        return SHRPX_OPTID_TLS_TICKET_KEY_CIPHER;
      }
      break;
    case 's':
      if (util::strieq("frontend-max-request"_sr, name, 20)) {
        return SHRPX_OPTID_FRONTEND_MAX_REQUESTS;
      }
      break;
    case 't':
      if (util::strieq("backend-write-timeou"_sr, name, 20)) {
        return SHRPX_OPTID_BACKEND_WRITE_TIMEOUT;
      }
      if (util::strieq("frontend-read-timeou"_sr, name, 20)) {
        return SHRPX_OPTID_FRONTEND_READ_TIMEOUT;
      }
      break;
    case 'y':
      if (util::strieq("accesslog-write-earl"_sr, name, 20)) {
        return SHRPX_OPTID_ACCESSLOG_WRITE_EARLY;
      }
      break;
    }
    break;
  case 22:
    switch (name[21]) {
    case 'i':
      if (util::strieq("backend-http-proxy-ur"_sr, name, 21)) {
        return SHRPX_OPTID_BACKEND_HTTP_PROXY_URI;
      }
      break;
    case 'r':
      if (util::strieq("backend-request-buffe"_sr, name, 21)) {
        return SHRPX_OPTID_BACKEND_REQUEST_BUFFER;
      }
      if (util::strieq("frontend-quic-qlog-di"_sr, name, 21)) {
        return SHRPX_OPTID_FRONTEND_QUIC_QLOG_DIR;
      }
      break;
    case 't':
      if (util::strieq("frontend-write-timeou"_sr, name, 21)) {
        return SHRPX_OPTID_FRONTEND_WRITE_TIMEOUT;
      }
      break;
    case 'y':
      if (util::strieq("backend-address-famil"_sr, name, 21)) {
        return SHRPX_OPTID_BACKEND_ADDRESS_FAMILY;
      }
      break;
    }
    break;
  case 23:
    switch (name[22]) {
    case 'e':
      if (util::strieq("client-private-key-fil"_sr, name, 22)) {
        return SHRPX_OPTID_CLIENT_PRIVATE_KEY_FILE;
      }
      if (util::strieq("private-key-passwd-fil"_sr, name, 22)) {
        return SHRPX_OPTID_PRIVATE_KEY_PASSWD_FILE;
      }
      break;
    case 'g':
      if (util::strieq("frontend-quic-debug-lo"_sr, name, 22)) {
        return SHRPX_OPTID_FRONTEND_QUIC_DEBUG_LOG;
      }
      break;
    case 'r':
      if (util::strieq("backend-response-buffe"_sr, name, 22)) {
        return SHRPX_OPTID_BACKEND_RESPONSE_BUFFER;
      }
      break;
    case 't':
      if (util::strieq("backend-connect-timeou"_sr, name, 22)) {
        return SHRPX_OPTID_BACKEND_CONNECT_TIMEOUT;
      }
      if (util::strieq("frontend-header-timeou"_sr, name, 22)) {
        return SHRPX_OPTID_FRONTEND_HEADER_TIMEOUT;
      }
      break;
    }
    break;
  case 24:
    switch (name[23]) {
    case 'a':
      if (util::strieq("frontend-quic-early-dat"_sr, name, 23)) {
        return SHRPX_OPTID_FRONTEND_QUIC_EARLY_DATA;
      }
      break;
    case 'd':
      if (util::strieq("strip-incoming-forwarde"_sr, name, 23)) {
        return SHRPX_OPTID_STRIP_INCOMING_FORWARDED;
      }
      if (util::strieq("tls-ticket-key-memcache"_sr, name, 23)) {
        return SHRPX_OPTID_TLS_TICKET_KEY_MEMCACHED;
      }
      break;
    case 'e':
      if (util::strieq("fetch-ocsp-response-fil"_sr, name, 23)) {
        return SHRPX_OPTID_FETCH_OCSP_RESPONSE_FILE;
      }
      break;
    case 'o':
      if (util::strieq("no-add-x-forwarded-prot"_sr, name, 23)) {
        return SHRPX_OPTID_NO_ADD_X_FORWARDED_PROTO;
      }
      break;
    case 't':
      if (util::strieq("listener-disable-timeou"_sr, name, 23)) {
        return SHRPX_OPTID_LISTENER_DISABLE_TIMEOUT;
      }
      if (util::strieq("tls-dyn-rec-idle-timeou"_sr, name, 23)) {
        return SHRPX_OPTID_TLS_DYN_REC_IDLE_TIMEOUT;
      }
      break;
    }
    break;
  case 25:
    switch (name[24]) {
    case 'e':
      if (util::strieq("backend-http2-window-siz"_sr, name, 24)) {
        return SHRPX_OPTID_BACKEND_HTTP2_WINDOW_SIZE;
      }
      if (util::strieq("frontend-quic-secret-fil"_sr, name, 24)) {
        return SHRPX_OPTID_FRONTEND_QUIC_SECRET_FILE;
      }
      break;
    case 'g':
      if (util::strieq("http2-no-cookie-crumblin"_sr, name, 24)) {
        return SHRPX_OPTID_HTTP2_NO_COOKIE_CRUMBLING;
      }
      break;
    case 's':
      if (util::strieq("backend-http2-window-bit"_sr, name, 24)) {
        return SHRPX_OPTID_BACKEND_HTTP2_WINDOW_BITS;
      }
      if (util::strieq("max-request-header-field"_sr, name, 24)) {
        return SHRPX_OPTID_MAX_REQUEST_HEADER_FIELDS;
      }
      break;
    case 't':
      if (util::strieq("frontend-quic-initial-rt"_sr, name, 24)) {
        return SHRPX_OPTID_FRONTEND_QUIC_INITIAL_RTT;
      }
      break;
    }
    break;
  case 26:
    switch (name[25]) {
    case 'a':
      if (util::strieq("tls-no-postpone-early-dat"_sr, name, 25)) {
        return SHRPX_OPTID_TLS_NO_POSTPONE_EARLY_DATA;
      }
      break;
    case 'e':
      if (util::strieq("frontend-http2-window-siz"_sr, name, 25)) {
        return SHRPX_OPTID_FRONTEND_HTTP2_WINDOW_SIZE;
      }
      if (util::strieq("frontend-http3-window-siz"_sr, name, 25)) {
        return SHRPX_OPTID_FRONTEND_HTTP3_WINDOW_SIZE;
      }
      break;
    case 's':
      if (util::strieq("frontend-http2-window-bit"_sr, name, 25)) {
        return SHRPX_OPTID_FRONTEND_HTTP2_WINDOW_BITS;
      }
      if (util::strieq("max-response-header-field"_sr, name, 25)) {
        return SHRPX_OPTID_MAX_RESPONSE_HEADER_FIELDS;
      }
      break;
    case 't':
      if (util::strieq("backend-keep-alive-timeou"_sr, name, 25)) {
        return SHRPX_OPTID_BACKEND_KEEP_ALIVE_TIMEOUT;
      }
      if (util::strieq("frontend-quic-idle-timeou"_sr, name, 25)) {
        return SHRPX_OPTID_FRONTEND_QUIC_IDLE_TIMEOUT;
      }
      if (util::strieq("no-http2-cipher-black-lis"_sr, name, 25)) {
        return SHRPX_OPTID_NO_HTTP2_CIPHER_BLACK_LIST;
      }
      if (util::strieq("no-http2-cipher-block-lis"_sr, name, 25)) {
        return SHRPX_OPTID_NO_HTTP2_CIPHER_BLOCK_LIST;
      }
      break;
    }
    break;
  case 27:
    switch (name[26]) {
    case 'd':
      if (util::strieq("tls-session-cache-memcache"_sr, name, 26)) {
        return SHRPX_OPTID_TLS_SESSION_CACHE_MEMCACHED;
      }
      break;
    case 'n':
      if (util::strieq("frontend-quic-require-toke"_sr, name, 26)) {
        return SHRPX_OPTID_FRONTEND_QUIC_REQUIRE_TOKEN;
      }
      break;
    case 'r':
      if (util::strieq("request-header-field-buffe"_sr, name, 26)) {
        return SHRPX_OPTID_REQUEST_HEADER_FIELD_BUFFER;
      }
      break;
    case 's':
      if (util::strieq("worker-frontend-connection"_sr, name, 26)) {
        return SHRPX_OPTID_WORKER_FRONTEND_CONNECTIONS;
      }
      break;
    case 't':
      if (util::strieq("frontend-http2-idle-timeou"_sr, name, 26)) {
        return SHRPX_OPTID_FRONTEND_HTTP2_IDLE_TIMEOUT;
      }
      if (util::strieq("frontend-http2-read-timeou"_sr, name, 26)) {
        return SHRPX_OPTID_FRONTEND_HTTP2_READ_TIMEOUT;
      }
      if (util::strieq("frontend-http3-idle-timeou"_sr, name, 26)) {
        return SHRPX_OPTID_FRONTEND_HTTP3_IDLE_TIMEOUT;
      }
      if (util::strieq("frontend-http3-read-timeou"_sr, name, 26)) {
        return SHRPX_OPTID_FRONTEND_HTTP3_READ_TIMEOUT;
      }
      if (util::strieq("frontend-keep-alive-timeou"_sr, name, 26)) {
        return SHRPX_OPTID_FRONTEND_KEEP_ALIVE_TIMEOUT;
      }
      break;
    }
    break;
  case 28:
    switch (name[27]) {
    case 'a':
      if (util::strieq("no-strip-incoming-early-dat"_sr, name, 27)) {
        return SHRPX_OPTID_NO_STRIP_INCOMING_EARLY_DATA;
      }
      break;
    case 'd':
      if (util::strieq("tls-dyn-rec-warmup-threshol"_sr, name, 27)) {
        return SHRPX_OPTID_TLS_DYN_REC_WARMUP_THRESHOLD;
      }
      break;
    case 'r':
      if (util::strieq("response-header-field-buffe"_sr, name, 27)) {
        return SHRPX_OPTID_RESPONSE_HEADER_FIELD_BUFFER;
      }
      break;
    case 's':
      if (util::strieq("http2-max-concurrent-stream"_sr, name, 27)) {
        return SHRPX_OPTID_HTTP2_MAX_CONCURRENT_STREAMS;
      }
      if (util::strieq("tls-ticket-key-memcached-tl"_sr, name, 27)) {
        return SHRPX_OPTID_TLS_TICKET_KEY_MEMCACHED_TLS;
      }
      break;
    case 't':
      if (util::strieq("backend-connections-per-hos"_sr, name, 27)) {
        return SHRPX_OPTID_BACKEND_CONNECTIONS_PER_HOST;
      }
      break;
    }
    break;
  case 30:
    switch (name[29]) {
    case 'd':
      if (util::strieq("verify-client-tolerate-expire"_sr, name, 29)) {
        return SHRPX_OPTID_VERIFY_CLIENT_TOLERATE_EXPIRED;
      }
      break;
    case 'e':
      if (util::strieq("frontend-http3-max-window-siz"_sr, name, 29)) {
        return SHRPX_OPTID_FRONTEND_HTTP3_MAX_WINDOW_SIZE;
      }
      break;
    case 'r':
      if (util::strieq("ignore-per-pattern-mruby-erro"_sr, name, 29)) {
        return SHRPX_OPTID_IGNORE_PER_PATTERN_MRUBY_ERROR;
      }
      if (util::strieq("strip-incoming-x-forwarded-fo"_sr, name, 29)) {
        return SHRPX_OPTID_STRIP_INCOMING_X_FORWARDED_FOR;
      }
      break;
    case 't':
      if (util::strieq("backend-http2-settings-timeou"_sr, name, 29)) {
        return SHRPX_OPTID_BACKEND_HTTP2_SETTINGS_TIMEOUT;
      }
      break;
    }
    break;
  case 31:
    switch (name[30]) {
    case 's':
      if (util::strieq("tls-session-cache-memcached-tl"_sr, name, 30)) {
        return SHRPX_OPTID_TLS_SESSION_CACHE_MEMCACHED_TLS;
      }
      break;
    case 't':
      if (util::strieq("frontend-http2-settings-timeou"_sr, name, 30)) {
        return SHRPX_OPTID_FRONTEND_HTTP2_SETTINGS_TIMEOUT;
      }
      break;
    }
    break;
  case 32:
    switch (name[31]) {
    case 'd':
      if (util::strieq("backend-connections-per-fronten"_sr, name, 31)) {
        return SHRPX_OPTID_BACKEND_CONNECTIONS_PER_FRONTEND;
      }
      break;
    }
    break;
  case 33:
    switch (name[32]) {
    case 'l':
      if (util::strieq("tls-ticket-key-memcached-interva"_sr, name, 32)) {
        return SHRPX_OPTID_TLS_TICKET_KEY_MEMCACHED_INTERVAL;
      }
      if (util::strieq("tls-ticket-key-memcached-max-fai"_sr, name, 32)) {
        return SHRPX_OPTID_TLS_TICKET_KEY_MEMCACHED_MAX_FAIL;
      }
      break;
    case 't':
      if (util::strieq("client-no-http2-cipher-black-lis"_sr, name, 32)) {
        return SHRPX_OPTID_CLIENT_NO_HTTP2_CIPHER_BLACK_LIST;
      }
      if (util::strieq("client-no-http2-cipher-block-lis"_sr, name, 32)) {
        return SHRPX_OPTID_CLIENT_NO_HTTP2_CIPHER_BLOCK_LIST;
      }
      break;
    }
    break;
  case 34:
    switch (name[33]) {
    case 'e':
      if (util::strieq("tls-ticket-key-memcached-cert-fil"_sr, name, 33)) {
        return SHRPX_OPTID_TLS_TICKET_KEY_MEMCACHED_CERT_FILE;
      }
      break;
    case 'r':
      if (util::strieq("frontend-http2-dump-request-heade"_sr, name, 33)) {
        return SHRPX_OPTID_FRONTEND_HTTP2_DUMP_REQUEST_HEADER;
      }
      break;
    case 't':
      if (util::strieq("backend-http1-connections-per-hos"_sr, name, 33)) {
        return SHRPX_OPTID_BACKEND_HTTP1_CONNECTIONS_PER_HOST;
      }
      break;
    case 'y':
      if (util::strieq("tls-ticket-key-memcached-max-retr"_sr, name, 33)) {
        return SHRPX_OPTID_TLS_TICKET_KEY_MEMCACHED_MAX_RETRY;
      }
      break;
    }
    break;
  case 35:
    switch (name[34]) {
    case 'e':
      if (util::strieq("frontend-http2-optimize-window-siz"_sr, name, 34)) {
        return SHRPX_OPTID_FRONTEND_HTTP2_OPTIMIZE_WINDOW_SIZE;
      }
      break;
    case 'o':
      if (util::strieq("no-strip-incoming-x-forwarded-prot"_sr, name, 34)) {
        return SHRPX_OPTID_NO_STRIP_INCOMING_X_FORWARDED_PROTO;
      }
      break;
    case 'r':
      if (util::strieq("frontend-http2-dump-response-heade"_sr, name, 34)) {
        return SHRPX_OPTID_FRONTEND_HTTP2_DUMP_RESPONSE_HEADER;
      }
      if (util::strieq("frontend-quic-congestion-controlle"_sr, name, 34)) {
        return SHRPX_OPTID_FRONTEND_QUIC_CONGESTION_CONTROLLER;
      }
      break;
    }
    break;
  case 36:
    switch (name[35]) {
    case 'd':
      if (util::strieq("worker-process-grace-shutdown-perio"_sr, name, 35)) {
        return SHRPX_OPTID_WORKER_PROCESS_GRACE_SHUTDOWN_PERIOD;
      }
      break;
    case 'e':
      if (util::strieq("backend-http2-connection-window-siz"_sr, name, 35)) {
        return SHRPX_OPTID_BACKEND_HTTP2_CONNECTION_WINDOW_SIZE;
      }
      break;
    case 'r':
      if (util::strieq("backend-http2-connections-per-worke"_sr, name, 35)) {
        return SHRPX_OPTID_BACKEND_HTTP2_CONNECTIONS_PER_WORKER;
      }
      break;
    case 's':
      if (util::strieq("backend-http2-connection-window-bit"_sr, name, 35)) {
        return SHRPX_OPTID_BACKEND_HTTP2_CONNECTION_WINDOW_BITS;
      }
      if (util::strieq("backend-http2-max-concurrent-stream"_sr, name, 35)) {
        return SHRPX_OPTID_BACKEND_HTTP2_MAX_CONCURRENT_STREAMS;
      }
      break;
    }
    break;
  case 37:
    switch (name[36]) {
    case 'e':
      if (util::strieq("frontend-http2-connection-window-siz"_sr, name, 36)) {
        return SHRPX_OPTID_FRONTEND_HTTP2_CONNECTION_WINDOW_SIZE;
      }
      if (util::strieq("frontend-http3-connection-window-siz"_sr, name, 36)) {
        return SHRPX_OPTID_FRONTEND_HTTP3_CONNECTION_WINDOW_SIZE;
      }
      if (util::strieq("tls-session-cache-memcached-cert-fil"_sr, name, 36)) {
        return SHRPX_OPTID_TLS_SESSION_CACHE_MEMCACHED_CERT_FILE;
      }
      break;
    case 's':
      if (util::strieq("frontend-http2-connection-window-bit"_sr, name, 36)) {
        return SHRPX_OPTID_FRONTEND_HTTP2_CONNECTION_WINDOW_BITS;
      }
      if (util::strieq("frontend-http2-max-concurrent-stream"_sr, name, 36)) {
        return SHRPX_OPTID_FRONTEND_HTTP2_MAX_CONCURRENT_STREAMS;
      }
      if (util::strieq("frontend-http3-max-concurrent-stream"_sr, name, 36)) {
        return SHRPX_OPTID_FRONTEND_HTTP3_MAX_CONCURRENT_STREAMS;
      }
      break;
    }
    break;
  case 38:
    switch (name[37]) {
    case 'd':
      if (util::strieq("backend-http1-connections-per-fronten"_sr, name, 37)) {
        return SHRPX_OPTID_BACKEND_HTTP1_CONNECTIONS_PER_FRONTEND;
      }
      break;
    }
    break;
  case 39:
    switch (name[38]) {
    case 'y':
      if (util::strieq("tls-ticket-key-memcached-address-famil"_sr, name, 38)) {
        return SHRPX_OPTID_TLS_TICKET_KEY_MEMCACHED_ADDRESS_FAMILY;
      }
      break;
    }
    break;
  case 40:
    switch (name[39]) {
    case 'e':
      if (util::strieq("backend-http2-decoder-dynamic-table-siz"_sr, name,
                       39)) {
        return SHRPX_OPTID_BACKEND_HTTP2_DECODER_DYNAMIC_TABLE_SIZE;
      }
      if (util::strieq("backend-http2-encoder-dynamic-table-siz"_sr, name,
                       39)) {
        return SHRPX_OPTID_BACKEND_HTTP2_ENCODER_DYNAMIC_TABLE_SIZE;
      }
      break;
    }
    break;
  case 41:
    switch (name[40]) {
    case 'e':
      if (util::strieq("frontend-http2-decoder-dynamic-table-siz"_sr, name,
                       40)) {
        return SHRPX_OPTID_FRONTEND_HTTP2_DECODER_DYNAMIC_TABLE_SIZE;
      }
      if (util::strieq("frontend-http2-encoder-dynamic-table-siz"_sr, name,
                       40)) {
        return SHRPX_OPTID_FRONTEND_HTTP2_ENCODER_DYNAMIC_TABLE_SIZE;
      }
      if (util::strieq("frontend-http2-optimize-write-buffer-siz"_sr, name,
                       40)) {
        return SHRPX_OPTID_FRONTEND_HTTP2_OPTIMIZE_WRITE_BUFFER_SIZE;
      }
      if (util::strieq("frontend-http3-max-connection-window-siz"_sr, name,
                       40)) {
        return SHRPX_OPTID_FRONTEND_HTTP3_MAX_CONNECTION_WINDOW_SIZE;
      }
      if (util::strieq("tls-ticket-key-memcached-private-key-fil"_sr, name,
                       40)) {
        return SHRPX_OPTID_TLS_TICKET_KEY_MEMCACHED_PRIVATE_KEY_FILE;
      }
      break;
    }
    break;
  case 42:
    switch (name[41]) {
    case 'y':
      if (util::strieq("tls-session-cache-memcached-address-famil"_sr, name,
                       41)) {
        return SHRPX_OPTID_TLS_SESSION_CACHE_MEMCACHED_ADDRESS_FAMILY;
      }
      break;
    }
    break;
  case 44:
    switch (name[43]) {
    case 'e':
      if (util::strieq("tls-session-cache-memcached-private-key-fil"_sr, name,
                       43)) {
        return SHRPX_OPTID_TLS_SESSION_CACHE_MEMCACHED_PRIVATE_KEY_FILE;
      }
      break;
    }
    break;
  }
  return -1;
}

int parse_config(Config *config, const StringRef &opt, const StringRef &optarg,
                 std::set<StringRef> &included_set,
                 std::map<StringRef, size_t> &pattern_addr_indexer) {
  auto optid = option_lookup_token(opt);
  return parse_config(config, optid, opt, optarg, included_set,
                      pattern_addr_indexer);
}

int parse_config(Config *config, int optid, const StringRef &opt,
                 const StringRef &optarg, std::set<StringRef> &included_set,
                 std::map<StringRef, size_t> &pattern_addr_indexer) {
  std::array<char, STRERROR_BUFSIZE> errbuf;
  char host[NI_MAXHOST];
  uint16_t port;

  switch (optid) {
  case SHRPX_OPTID_BACKEND: {
    auto &downstreamconf = *config->conn.downstream;
    auto addr_end = std::find(std::begin(optarg), std::end(optarg), ';');

    DownstreamAddrConfig addr{};
    if (util::istarts_with(optarg, SHRPX_UNIX_PATH_PREFIX)) {
      auto path = std::begin(optarg) + SHRPX_UNIX_PATH_PREFIX.size();
      addr.host =
          make_string_ref(downstreamconf.balloc, StringRef{path, addr_end});
      addr.host_unix = true;
    } else {
      if (split_host_port(host, sizeof(host), &port,
                          StringRef{std::begin(optarg), addr_end}, opt) == -1) {
        return -1;
      }

      addr.host = make_string_ref(downstreamconf.balloc, StringRef{host});
      addr.port = port;
    }

    auto mapping = addr_end == std::end(optarg) ? addr_end : addr_end + 1;
    auto mapping_end = std::find(mapping, std::end(optarg), ';');

    auto params =
        mapping_end == std::end(optarg) ? mapping_end : mapping_end + 1;

    if (parse_mapping(config, addr, pattern_addr_indexer,
                      StringRef{mapping, mapping_end},
                      StringRef{params, std::end(optarg)}) != 0) {
      return -1;
    }

    return 0;
  }
  case SHRPX_OPTID_FRONTEND: {
    auto &apiconf = config->api;

    auto addr_end = std::find(std::begin(optarg), std::end(optarg), ';');
    auto src_params = StringRef{addr_end, std::end(optarg)};

    UpstreamParams params{};
    params.tls = true;

    if (parse_upstream_params(params, src_params) != 0) {
      return -1;
    }

    if (params.sni_fwd && !params.tls) {
      LOG(ERROR) << "frontend: sni_fwd requires tls";
      return -1;
    }

    if (params.quic) {
      if (params.alt_mode != UpstreamAltMode::NONE) {
        LOG(ERROR) << "frontend: api or healthmon cannot be used with quic";
        return -1;
      }

      if (!params.tls) {
        LOG(ERROR) << "frontend: quic requires TLS";
        return -1;
      }
    }

    UpstreamAddr addr{};
    addr.fd = -1;
    addr.tls = params.tls;
    addr.sni_fwd = params.sni_fwd;
    addr.alt_mode = params.alt_mode;
    addr.accept_proxy_protocol = params.proxyproto;
    addr.quic = params.quic;

    if (addr.alt_mode == UpstreamAltMode::API) {
      apiconf.enabled = true;
    }

#ifdef ENABLE_HTTP3
    auto &addrs = params.quic ? config->conn.quic_listener.addrs
                              : config->conn.listener.addrs;
#else  // !ENABLE_HTTP3
    auto &addrs = config->conn.listener.addrs;
#endif // !ENABLE_HTTP3

    if (util::istarts_with(optarg, SHRPX_UNIX_PATH_PREFIX)) {
      if (addr.quic) {
        LOG(ERROR) << "frontend: quic cannot be used on UNIX domain socket";
        return -1;
      }

      auto path = std::begin(optarg) + SHRPX_UNIX_PATH_PREFIX.size();
      addr.host = make_string_ref(config->balloc, StringRef{path, addr_end});
      addr.host_unix = true;
      addr.index = addrs.size();

      addrs.push_back(std::move(addr));

      return 0;
    }

    if (split_host_port(host, sizeof(host), &port,
                        StringRef{std::begin(optarg), addr_end}, opt) == -1) {
      return -1;
    }

    addr.host = make_string_ref(config->balloc, StringRef{host});
    addr.port = port;

    if (util::numeric_host(host, AF_INET)) {
      addr.family = AF_INET;
      addr.index = addrs.size();
      addrs.push_back(std::move(addr));
      return 0;
    }

    if (util::numeric_host(host, AF_INET6)) {
      addr.family = AF_INET6;
      addr.index = addrs.size();
      addrs.push_back(std::move(addr));
      return 0;
    }

    addr.family = AF_INET;
    addr.index = addrs.size();
    addrs.push_back(addr);

    addr.family = AF_INET6;
    addr.index = addrs.size();
    addrs.push_back(std::move(addr));

    return 0;
  }
  case SHRPX_OPTID_WORKERS: {
#ifdef NOTHREADS
    LOG(WARN) << "Threading disabled at build time, no threads created.";
    return 0;
#else  // !NOTHREADS
    size_t n;

    if (parse_uint(&n, opt, optarg) != 0) {
      return -1;
    }

    if (n > 65530) {
      LOG(ERROR) << opt << ": the number of workers must not exceed 65530";

      return -1;
    }

    config->num_worker = n;

    return 0;
#endif // !NOTHREADS
  }
  case SHRPX_OPTID_HTTP2_MAX_CONCURRENT_STREAMS: {
    LOG(WARN) << opt << ": deprecated. Use "
              << SHRPX_OPT_FRONTEND_HTTP2_MAX_CONCURRENT_STREAMS << " and "
              << SHRPX_OPT_BACKEND_HTTP2_MAX_CONCURRENT_STREAMS << " instead.";
    size_t n;
    if (parse_uint(&n, opt, optarg) != 0) {
      return -1;
    }
    auto &http2conf = config->http2;
    http2conf.upstream.max_concurrent_streams = n;
    http2conf.downstream.max_concurrent_streams = n;

    return 0;
  }
  case SHRPX_OPTID_LOG_LEVEL: {
    auto level = Log::get_severity_level_by_name(optarg);
    if (level == -1) {
      LOG(ERROR) << opt << ": Invalid severity level: " << optarg;
      return -1;
    }
    config->logging.severity = level;

    return 0;
  }
  case SHRPX_OPTID_DAEMON:
    config->daemon = util::strieq("yes"_sr, optarg);

    return 0;
  case SHRPX_OPTID_HTTP2_PROXY:
    config->http2_proxy = util::strieq("yes"_sr, optarg);

    return 0;
  case SHRPX_OPTID_HTTP2_BRIDGE:
    LOG(ERROR) << opt
               << ": deprecated.  Use backend=<addr>,<port>;;proto=h2;tls";
    return -1;
  case SHRPX_OPTID_CLIENT_PROXY:
    LOG(ERROR)
        << opt
        << ": deprecated.  Use http2-proxy, frontend=<addr>,<port>;no-tls "
           "and backend=<addr>,<port>;;proto=h2;tls";
    return -1;
  case SHRPX_OPTID_ADD_X_FORWARDED_FOR:
    config->http.xff.add = util::strieq("yes"_sr, optarg);

    return 0;
  case SHRPX_OPTID_STRIP_INCOMING_X_FORWARDED_FOR:
    config->http.xff.strip_incoming = util::strieq("yes"_sr, optarg);

    return 0;
  case SHRPX_OPTID_NO_VIA:
    config->http.no_via = util::strieq("yes"_sr, optarg);

    return 0;
  case SHRPX_OPTID_FRONTEND_HTTP2_READ_TIMEOUT:
    LOG(WARN) << opt << ": deprecated.  Use frontend-http2-idle-timeout";
    // fall through
  case SHRPX_OPTID_FRONTEND_HTTP2_IDLE_TIMEOUT:
    return parse_duration(&config->conn.upstream.timeout.http2_idle, opt,
                          optarg);
  case SHRPX_OPTID_FRONTEND_READ_TIMEOUT:
    LOG(WARN) << opt << ": deprecated.  Use frontend-header-timeout";

    return 0;
  case SHRPX_OPTID_FRONTEND_HEADER_TIMEOUT:
    return parse_duration(&config->http.timeout.header, opt, optarg);
  case SHRPX_OPTID_FRONTEND_WRITE_TIMEOUT:
    return parse_duration(&config->conn.upstream.timeout.write, opt, optarg);
  case SHRPX_OPTID_BACKEND_READ_TIMEOUT:
    return parse_duration(&config->conn.downstream->timeout.read, opt, optarg);
  case SHRPX_OPTID_BACKEND_WRITE_TIMEOUT:
    return parse_duration(&config->conn.downstream->timeout.write, opt, optarg);
  case SHRPX_OPTID_BACKEND_CONNECT_TIMEOUT:
    return parse_duration(&config->conn.downstream->timeout.connect, opt,
                          optarg);
  case SHRPX_OPTID_STREAM_READ_TIMEOUT:
    return parse_duration(&config->http2.timeout.stream_read, opt, optarg);
  case SHRPX_OPTID_STREAM_WRITE_TIMEOUT:
    return parse_duration(&config->http2.timeout.stream_write, opt, optarg);
  case SHRPX_OPTID_ACCESSLOG_FILE:
    config->logging.access.file = make_string_ref(config->balloc, optarg);

    return 0;
  case SHRPX_OPTID_ACCESSLOG_SYSLOG:
    config->logging.access.syslog = util::strieq("yes"_sr, optarg);

    return 0;
  case SHRPX_OPTID_ACCESSLOG_FORMAT:
    config->logging.access.format = parse_log_format(config->balloc, optarg);

    return 0;
  case SHRPX_OPTID_ERRORLOG_FILE:
    config->logging.error.file = make_string_ref(config->balloc, optarg);

    return 0;
  case SHRPX_OPTID_ERRORLOG_SYSLOG:
    config->logging.error.syslog = util::strieq("yes"_sr, optarg);

    return 0;
  case SHRPX_OPTID_FASTOPEN:
    return parse_uint(&config->conn.listener.fastopen, opt, optarg);
  case SHRPX_OPTID_BACKEND_KEEP_ALIVE_TIMEOUT:
    return parse_duration(&config->conn.downstream->timeout.idle_read, opt,
                          optarg);
  case SHRPX_OPTID_FRONTEND_HTTP2_WINDOW_BITS:
  case SHRPX_OPTID_BACKEND_HTTP2_WINDOW_BITS: {
    LOG(WARN) << opt << ": deprecated.  Use "
              << (optid == SHRPX_OPTID_FRONTEND_HTTP2_WINDOW_BITS
                      ? SHRPX_OPT_FRONTEND_HTTP2_WINDOW_SIZE
                      : SHRPX_OPT_BACKEND_HTTP2_WINDOW_SIZE);
    int32_t *resp;

    if (optid == SHRPX_OPTID_FRONTEND_HTTP2_WINDOW_BITS) {
      resp = &config->http2.upstream.window_size;
    } else {
      resp = &config->http2.downstream.window_size;
    }

    errno = 0;

    int n;

    if (parse_uint(&n, opt, optarg) != 0) {
      return -1;
    }

    if (n >= 31) {
      LOG(ERROR) << opt
                 << ": specify the integer in the range [0, 30], inclusive";
      return -1;
    }

    // Make 16 bits to the HTTP/2 default 64KiB - 1.  This is the same
    // behaviour of previous code.
    *resp = (1 << n) - 1;

    return 0;
  }
  case SHRPX_OPTID_FRONTEND_HTTP2_CONNECTION_WINDOW_BITS:
  case SHRPX_OPTID_BACKEND_HTTP2_CONNECTION_WINDOW_BITS: {
    LOG(WARN) << opt << ": deprecated.  Use "
              << (optid == SHRPX_OPTID_FRONTEND_HTTP2_CONNECTION_WINDOW_BITS
                      ? SHRPX_OPT_FRONTEND_HTTP2_CONNECTION_WINDOW_SIZE
                      : SHRPX_OPT_BACKEND_HTTP2_CONNECTION_WINDOW_SIZE);
    int32_t *resp;

    if (optid == SHRPX_OPTID_FRONTEND_HTTP2_CONNECTION_WINDOW_BITS) {
      resp = &config->http2.upstream.connection_window_size;
    } else {
      resp = &config->http2.downstream.connection_window_size;
    }

    errno = 0;

    int n;

    if (parse_uint(&n, opt, optarg) != 0) {
      return -1;
    }

    if (n < 16 || n >= 31) {
      LOG(ERROR) << opt
                 << ": specify the integer in the range [16, 30], inclusive";
      return -1;
    }

    *resp = (1 << n) - 1;

    return 0;
  }
  case SHRPX_OPTID_FRONTEND_NO_TLS:
    LOG(WARN) << opt << ": deprecated.  Use no-tls keyword in "
              << SHRPX_OPT_FRONTEND;
    return 0;
  case SHRPX_OPTID_BACKEND_NO_TLS:
    LOG(WARN) << opt
              << ": deprecated.  backend connection is not encrypted by "
                 "default.  See also "
              << SHRPX_OPT_BACKEND_TLS;
    return 0;
  case SHRPX_OPTID_BACKEND_TLS_SNI_FIELD:
    LOG(WARN) << opt
              << ": deprecated.  Use sni keyword in --backend option.  "
                 "For now, all sni values of all backends are "
                 "overridden by the given value "
              << optarg;
    config->tls.backend_sni_name = make_string_ref(config->balloc, optarg);

    return 0;
  case SHRPX_OPTID_PID_FILE:
    config->pid_file = make_string_ref(config->balloc, optarg);

    return 0;
  case SHRPX_OPTID_USER: {
    auto pwd = getpwnam(optarg.data());
    if (!pwd) {
      LOG(ERROR) << opt << ": failed to get uid from " << optarg << ": "
                 << xsi_strerror(errno, errbuf.data(), errbuf.size());
      return -1;
    }
    config->user = make_string_ref(config->balloc, StringRef{pwd->pw_name});
    config->uid = pwd->pw_uid;
    config->gid = pwd->pw_gid;

    return 0;
  }
  case SHRPX_OPTID_PRIVATE_KEY_FILE:
    config->tls.private_key_file = make_string_ref(config->balloc, optarg);

    return 0;
  case SHRPX_OPTID_PRIVATE_KEY_PASSWD_FILE: {
    auto passwd = read_passwd_from_file(opt, optarg);
    if (passwd.empty()) {
      LOG(ERROR) << opt << ": Couldn't read key file's passwd from " << optarg;
      return -1;
    }
    config->tls.private_key_passwd =
        make_string_ref(config->balloc, StringRef{passwd});

    return 0;
  }
  case SHRPX_OPTID_CERTIFICATE_FILE:
    config->tls.cert_file = make_string_ref(config->balloc, optarg);

    return 0;
  case SHRPX_OPTID_DH_PARAM_FILE:
    config->tls.dh_param_file = make_string_ref(config->balloc, optarg);

    return 0;
  case SHRPX_OPTID_SUBCERT: {
    auto end_keys = std::find(std::begin(optarg), std::end(optarg), ';');
    auto src_params = StringRef{end_keys, std::end(optarg)};

    SubcertParams params;
    if (parse_subcert_params(params, src_params) != 0) {
      return -1;
    }

    std::vector<uint8_t> sct_data;

    if (!params.sct_dir.empty()) {
      // Make sure that dir_path is NULL terminated string.
      if (read_tls_sct_from_dir(sct_data, opt,
                                StringRef{std::string{params.sct_dir}}) != 0) {
        return -1;
      }
    }

    // Private Key file and certificate file separated by ':'.
    auto sp = std::find(std::begin(optarg), end_keys, ':');
    if (sp == end_keys) {
      LOG(ERROR) << opt << ": missing ':' in "
                 << StringRef{std::begin(optarg), end_keys};
      return -1;
    }

    auto private_key_file = StringRef{std::begin(optarg), sp};

    if (private_key_file.empty()) {
      LOG(ERROR) << opt << ": missing private key file: "
                 << StringRef{std::begin(optarg), end_keys};
      return -1;
    }

    auto cert_file = StringRef{sp + 1, end_keys};

    if (cert_file.empty()) {
      LOG(ERROR) << opt << ": missing certificate file: "
                 << StringRef{std::begin(optarg), end_keys};
      return -1;
    }

    config->tls.subcerts.emplace_back(
        make_string_ref(config->balloc, private_key_file),
        make_string_ref(config->balloc, cert_file), std::move(sct_data));

    return 0;
  }
  case SHRPX_OPTID_SYSLOG_FACILITY: {
    int facility = int_syslog_facility(optarg);
    if (facility == -1) {
      LOG(ERROR) << opt << ": Unknown syslog facility: " << optarg;
      return -1;
    }
    config->logging.syslog_facility = facility;

    return 0;
  }
  case SHRPX_OPTID_BACKLOG:
    return parse_uint(&config->conn.listener.backlog, opt, optarg);
  case SHRPX_OPTID_CIPHERS:
    config->tls.ciphers = make_string_ref(config->balloc, optarg);

    return 0;
  case SHRPX_OPTID_TLS13_CIPHERS:
    config->tls.tls13_ciphers = make_string_ref(config->balloc, optarg);

    return 0;
  case SHRPX_OPTID_CLIENT:
    LOG(ERROR) << opt
               << ": deprecated.  Use frontend=<addr>,<port>;no-tls, "
                  "backend=<addr>,<port>;;proto=h2;tls";
    return -1;
  case SHRPX_OPTID_INSECURE:
    config->tls.insecure = util::strieq("yes"_sr, optarg);

    return 0;
  case SHRPX_OPTID_CACERT:
    config->tls.cacert = make_string_ref(config->balloc, optarg);

    return 0;
  case SHRPX_OPTID_BACKEND_IPV4:
    LOG(WARN) << opt
              << ": deprecated.  Use backend-address-family=IPv4 instead.";

    config->conn.downstream->family = AF_INET;

    return 0;
  case SHRPX_OPTID_BACKEND_IPV6:
    LOG(WARN) << opt
              << ": deprecated.  Use backend-address-family=IPv6 instead.";

    config->conn.downstream->family = AF_INET6;

    return 0;
  case SHRPX_OPTID_BACKEND_HTTP_PROXY_URI: {
    auto &proxy = config->downstream_http_proxy;
    // Reset here so that multiple option occurrence does not merge
    // the results.
    proxy = {};
    // parse URI and get hostname, port and optionally userinfo.
    http_parser_url u{};
    int rv = http_parser_parse_url(optarg.data(), optarg.size(), 0, &u);
    if (rv == 0) {
      if (u.field_set & UF_USERINFO) {
        auto uf = util::get_uri_field(optarg.data(), u, UF_USERINFO);
        // Surprisingly, u.field_set & UF_USERINFO is nonzero even if
        // userinfo component is empty string.
        if (!uf.empty()) {
          proxy.userinfo = util::percent_decode(config->balloc, uf);
        }
      }
      if (u.field_set & UF_HOST) {
        proxy.host = make_string_ref(
            config->balloc, util::get_uri_field(optarg.data(), u, UF_HOST));
      } else {
        LOG(ERROR) << opt << ": no hostname specified";
        return -1;
      }
      if (u.field_set & UF_PORT) {
        proxy.port = u.port;
      } else {
        LOG(ERROR) << opt << ": no port specified";
        return -1;
      }
    } else {
      LOG(ERROR) << opt << ": parse error";
      return -1;
    }

    return 0;
  }
  case SHRPX_OPTID_READ_RATE:
    return parse_uint_with_unit(&config->conn.upstream.ratelimit.read.rate, opt,
                                optarg);
  case SHRPX_OPTID_READ_BURST:
    return parse_uint_with_unit(&config->conn.upstream.ratelimit.read.burst,
                                opt, optarg);
  case SHRPX_OPTID_WRITE_RATE:
    return parse_uint_with_unit(&config->conn.upstream.ratelimit.write.rate,
                                opt, optarg);
  case SHRPX_OPTID_WRITE_BURST:
    return parse_uint_with_unit(&config->conn.upstream.ratelimit.write.burst,
                                opt, optarg);
  case SHRPX_OPTID_WORKER_READ_RATE:
    LOG(WARN) << opt << ": not implemented yet";
    return 0;
  case SHRPX_OPTID_WORKER_READ_BURST:
    LOG(WARN) << opt << ": not implemented yet";
    return 0;
  case SHRPX_OPTID_WORKER_WRITE_RATE:
    LOG(WARN) << opt << ": not implemented yet";
    return 0;
  case SHRPX_OPTID_WORKER_WRITE_BURST:
    LOG(WARN) << opt << ": not implemented yet";
    return 0;
  case SHRPX_OPTID_TLS_PROTO_LIST: {
    LOG(WARN) << opt
              << ": deprecated.  Use tls-min-proto-version and "
                 "tls-max-proto-version instead.";
    auto list = util::split_str(optarg, ',');
    config->tls.tls_proto_list.resize(list.size());
    for (size_t i = 0; i < list.size(); ++i) {
      config->tls.tls_proto_list[i] = make_string_ref(config->balloc, list[i]);
    }

    return 0;
  }
  case SHRPX_OPTID_VERIFY_CLIENT:
    config->tls.client_verify.enabled = util::strieq("yes"_sr, optarg);

    return 0;
  case SHRPX_OPTID_VERIFY_CLIENT_CACERT:
    config->tls.client_verify.cacert = make_string_ref(config->balloc, optarg);

    return 0;
  case SHRPX_OPTID_CLIENT_PRIVATE_KEY_FILE:
    config->tls.client.private_key_file =
        make_string_ref(config->balloc, optarg);

    return 0;
  case SHRPX_OPTID_CLIENT_CERT_FILE:
    config->tls.client.cert_file = make_string_ref(config->balloc, optarg);

    return 0;
  case SHRPX_OPTID_FRONTEND_HTTP2_DUMP_REQUEST_HEADER:
    config->http2.upstream.debug.dump.request_header_file =
        make_string_ref(config->balloc, optarg);

    return 0;
  case SHRPX_OPTID_FRONTEND_HTTP2_DUMP_RESPONSE_HEADER:
    config->http2.upstream.debug.dump.response_header_file =
        make_string_ref(config->balloc, optarg);

    return 0;
  case SHRPX_OPTID_HTTP2_NO_COOKIE_CRUMBLING:
    config->http2.no_cookie_crumbling = util::strieq("yes"_sr, optarg);

    return 0;
  case SHRPX_OPTID_FRONTEND_FRAME_DEBUG:
    config->http2.upstream.debug.frame_debug = util::strieq("yes"_sr, optarg);

    return 0;
  case SHRPX_OPTID_PADDING:
    return parse_uint(&config->padding, opt, optarg);
  case SHRPX_OPTID_ALTSVC: {
    AltSvc altsvc{};

    if (parse_altsvc(altsvc, opt, optarg) != 0) {
      return -1;
    }

    config->http.altsvcs.push_back(std::move(altsvc));

    return 0;
  }
  case SHRPX_OPTID_ADD_REQUEST_HEADER:
  case SHRPX_OPTID_ADD_RESPONSE_HEADER: {
    auto p = parse_header(config->balloc, optarg);
    if (p.name.empty()) {
      LOG(ERROR) << opt << ": invalid header field: " << optarg;
      return -1;
    }
    if (optid == SHRPX_OPTID_ADD_REQUEST_HEADER) {
      config->http.add_request_headers.push_back(std::move(p));
    } else {
      config->http.add_response_headers.push_back(std::move(p));
    }
    return 0;
  }
  case SHRPX_OPTID_WORKER_FRONTEND_CONNECTIONS:
    return parse_uint(&config->conn.upstream.worker_connections, opt, optarg);
  case SHRPX_OPTID_NO_LOCATION_REWRITE:
    config->http.no_location_rewrite = util::strieq("yes"_sr, optarg);

    return 0;
  case SHRPX_OPTID_NO_HOST_REWRITE:
    LOG(WARN) << SHRPX_OPT_NO_HOST_REWRITE
              << ": deprecated.  :authority and host header fields are NOT "
                 "altered by default.  To rewrite these headers, use "
                 "--host-rewrite option.";

    return 0;
  case SHRPX_OPTID_BACKEND_HTTP1_CONNECTIONS_PER_HOST:
    LOG(WARN) << opt
              << ": deprecated.  Use backend-connections-per-host instead.";
  // fall through
  case SHRPX_OPTID_BACKEND_CONNECTIONS_PER_HOST: {
    int n;

    if (parse_uint(&n, opt, optarg) != 0) {
      return -1;
    }

    if (n == 0) {
      LOG(ERROR) << opt << ": specify an integer strictly more than 0";

      return -1;
    }

    config->conn.downstream->connections_per_host = n;

    return 0;
  }
  case SHRPX_OPTID_BACKEND_HTTP1_CONNECTIONS_PER_FRONTEND:
    LOG(WARN) << opt << ": deprecated.  Use "
              << SHRPX_OPT_BACKEND_CONNECTIONS_PER_FRONTEND << " instead.";
  // fall through
  case SHRPX_OPTID_BACKEND_CONNECTIONS_PER_FRONTEND:
    return parse_uint(&config->conn.downstream->connections_per_frontend, opt,
                      optarg);
  case SHRPX_OPTID_LISTENER_DISABLE_TIMEOUT:
    return parse_duration(&config->conn.listener.timeout.sleep, opt, optarg);
  case SHRPX_OPTID_TLS_TICKET_KEY_FILE:
    config->tls.ticket.files.emplace_back(
        make_string_ref(config->balloc, optarg));
    return 0;
  case SHRPX_OPTID_RLIMIT_NOFILE: {
    int n;

    if (parse_uint(&n, opt, optarg) != 0) {
      return -1;
    }

    if (n < 0) {
      LOG(ERROR) << opt << ": specify the integer more than or equal to 0";

      return -1;
    }

    config->rlimit_nofile = n;

    return 0;
  }
  case SHRPX_OPTID_BACKEND_REQUEST_BUFFER:
  case SHRPX_OPTID_BACKEND_RESPONSE_BUFFER: {
    size_t n;
    if (parse_uint_with_unit(&n, opt, optarg) != 0) {
      return -1;
    }

    if (n == 0) {
      LOG(ERROR) << opt << ": specify an integer strictly more than 0";

      return -1;
    }

    if (optid == SHRPX_OPTID_BACKEND_REQUEST_BUFFER) {
      config->conn.downstream->request_buffer_size = n;
    } else {
      config->conn.downstream->response_buffer_size = n;
    }

    return 0;
  }

  case SHRPX_OPTID_NO_SERVER_PUSH:
    config->http2.no_server_push = util::strieq("yes"_sr, optarg);

    return 0;
  case SHRPX_OPTID_BACKEND_HTTP2_CONNECTIONS_PER_WORKER:
    LOG(WARN) << opt << ": deprecated.";
    return 0;
  case SHRPX_OPTID_FETCH_OCSP_RESPONSE_FILE:
    config->tls.ocsp.fetch_ocsp_response_file =
        make_string_ref(config->balloc, optarg);

    return 0;
  case SHRPX_OPTID_OCSP_UPDATE_INTERVAL:
    return parse_duration(&config->tls.ocsp.update_interval, opt, optarg);
  case SHRPX_OPTID_NO_OCSP:
    config->tls.ocsp.disabled = util::strieq("yes"_sr, optarg);

    return 0;
  case SHRPX_OPTID_HEADER_FIELD_BUFFER:
    LOG(WARN) << opt
              << ": deprecated.  Use request-header-field-buffer instead.";
  // fall through
  case SHRPX_OPTID_REQUEST_HEADER_FIELD_BUFFER:
    return parse_uint_with_unit(&config->http.request_header_field_buffer, opt,
                                optarg);
  case SHRPX_OPTID_MAX_HEADER_FIELDS:
    LOG(WARN) << opt << ": deprecated.  Use max-request-header-fields instead.";
  // fall through
  case SHRPX_OPTID_MAX_REQUEST_HEADER_FIELDS:
    return parse_uint(&config->http.max_request_header_fields, opt, optarg);
  case SHRPX_OPTID_RESPONSE_HEADER_FIELD_BUFFER:
    return parse_uint_with_unit(&config->http.response_header_field_buffer, opt,
                                optarg);
  case SHRPX_OPTID_MAX_RESPONSE_HEADER_FIELDS:
    return parse_uint(&config->http.max_response_header_fields, opt, optarg);
  case SHRPX_OPTID_INCLUDE: {
    if (included_set.count(optarg)) {
      LOG(ERROR) << opt << ": " << optarg << " has already been included";
      return -1;
    }

    included_set.insert(optarg);
    auto rv =
        load_config(config, optarg.data(), included_set, pattern_addr_indexer);
    included_set.erase(optarg);

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

    return 0;
  }
  case SHRPX_OPTID_TLS_TICKET_KEY_CIPHER:
    if (util::strieq("aes-128-cbc"_sr, optarg)) {
      config->tls.ticket.cipher = EVP_aes_128_cbc();
    } else if (util::strieq("aes-256-cbc"_sr, optarg)) {
      config->tls.ticket.cipher = EVP_aes_256_cbc();
    } else {
      LOG(ERROR) << opt
                 << ": unsupported cipher for ticket encryption: " << optarg;
      return -1;
    }
    config->tls.ticket.cipher_given = true;

    return 0;
  case SHRPX_OPTID_HOST_REWRITE:
    config->http.no_host_rewrite = !util::strieq("yes"_sr, optarg);

    return 0;
  case SHRPX_OPTID_TLS_SESSION_CACHE_MEMCACHED:
  case SHRPX_OPTID_TLS_TICKET_KEY_MEMCACHED: {
    auto addr_end = std::find(std::begin(optarg), std::end(optarg), ';');
    auto src_params = StringRef{addr_end, std::end(optarg)};

    MemcachedConnectionParams params{};
    if (parse_memcached_connection_params(params, src_params, StringRef{opt}) !=
        0) {
      return -1;
    }

    if (split_host_port(host, sizeof(host), &port,
                        StringRef{std::begin(optarg), addr_end}, opt) == -1) {
      return -1;
    }

    switch (optid) {
    case SHRPX_OPTID_TLS_SESSION_CACHE_MEMCACHED: {
      auto &memcachedconf = config->tls.session_cache.memcached;
      memcachedconf.host = make_string_ref(config->balloc, StringRef{host});
      memcachedconf.port = port;
      memcachedconf.tls = params.tls;
      break;
    }
    case SHRPX_OPTID_TLS_TICKET_KEY_MEMCACHED: {
      auto &memcachedconf = config->tls.ticket.memcached;
      memcachedconf.host = make_string_ref(config->balloc, StringRef{host});
      memcachedconf.port = port;
      memcachedconf.tls = params.tls;
      break;
    }
    };

    return 0;
  }
  case SHRPX_OPTID_TLS_TICKET_KEY_MEMCACHED_INTERVAL:
    return parse_duration(&config->tls.ticket.memcached.interval, opt, optarg);
  case SHRPX_OPTID_TLS_TICKET_KEY_MEMCACHED_MAX_RETRY: {
    int n;
    if (parse_uint(&n, opt, optarg) != 0) {
      return -1;
    }

    if (n > 30) {
      LOG(ERROR) << opt << ": must be smaller than or equal to 30";
      return -1;
    }

    config->tls.ticket.memcached.max_retry = n;
    return 0;
  }
  case SHRPX_OPTID_TLS_TICKET_KEY_MEMCACHED_MAX_FAIL:
    return parse_uint(&config->tls.ticket.memcached.max_fail, opt, optarg);
  case SHRPX_OPTID_TLS_DYN_REC_WARMUP_THRESHOLD: {
    size_t n;
    if (parse_uint_with_unit(&n, opt, optarg) != 0) {
      return -1;
    }

    config->tls.dyn_rec.warmup_threshold = n;

    return 0;
  }

  case SHRPX_OPTID_TLS_DYN_REC_IDLE_TIMEOUT:
    return parse_duration(&config->tls.dyn_rec.idle_timeout, opt, optarg);

  case SHRPX_OPTID_MRUBY_FILE:
#ifdef HAVE_MRUBY
    config->mruby_file = make_string_ref(config->balloc, optarg);
#else  // !HAVE_MRUBY
    LOG(WARN) << opt
              << ": ignored because mruby support is disabled at build time.";
#endif // !HAVE_MRUBY
    return 0;
  case SHRPX_OPTID_ACCEPT_PROXY_PROTOCOL:
    LOG(WARN) << opt << ": deprecated.  Use proxyproto keyword in "
              << SHRPX_OPT_FRONTEND << " instead.";
    config->conn.upstream.accept_proxy_protocol =
        util::strieq("yes"_sr, optarg);

    return 0;
  case SHRPX_OPTID_ADD_FORWARDED: {
    auto &fwdconf = config->http.forwarded;
    fwdconf.params = FORWARDED_NONE;
    for (const auto &param : util::split_str(optarg, ',')) {
      if (util::strieq("by"_sr, param)) {
        fwdconf.params |= FORWARDED_BY;
        continue;
      }
      if (util::strieq("for"_sr, param)) {
        fwdconf.params |= FORWARDED_FOR;
        continue;
      }
      if (util::strieq("host"_sr, param)) {
        fwdconf.params |= FORWARDED_HOST;
        continue;
      }
      if (util::strieq("proto"_sr, param)) {
        fwdconf.params |= FORWARDED_PROTO;
        continue;
      }

      LOG(ERROR) << opt << ": unknown parameter " << optarg;

      return -1;
    }

    return 0;
  }
  case SHRPX_OPTID_STRIP_INCOMING_FORWARDED:
    config->http.forwarded.strip_incoming = util::strieq("yes"_sr, optarg);

    return 0;
  case SHRPX_OPTID_FORWARDED_BY:
  case SHRPX_OPTID_FORWARDED_FOR: {
    auto type = parse_forwarded_node_type(optarg);

    if (type == static_cast<ForwardedNode>(-1) ||
        (optid == SHRPX_OPTID_FORWARDED_FOR && optarg[0] == '_')) {
      LOG(ERROR) << opt << ": unknown node type or illegal obfuscated string "
                 << optarg;
      return -1;
    }

    auto &fwdconf = config->http.forwarded;

    switch (optid) {
    case SHRPX_OPTID_FORWARDED_BY:
      fwdconf.by_node_type = type;
      if (optarg[0] == '_') {
        fwdconf.by_obfuscated = make_string_ref(config->balloc, optarg);
      } else {
        fwdconf.by_obfuscated = ""_sr;
      }
      break;
    case SHRPX_OPTID_FORWARDED_FOR:
      fwdconf.for_node_type = type;
      break;
    }

    return 0;
  }
  case SHRPX_OPTID_NO_HTTP2_CIPHER_BLACK_LIST:
    LOG(WARN) << opt << ": deprecated.  Use "
              << SHRPX_OPT_NO_HTTP2_CIPHER_BLOCK_LIST << " instead.";
    // fall through
  case SHRPX_OPTID_NO_HTTP2_CIPHER_BLOCK_LIST:
    config->tls.no_http2_cipher_block_list = util::strieq("yes"_sr, optarg);
    return 0;
  case SHRPX_OPTID_BACKEND_HTTP1_TLS:
  case SHRPX_OPTID_BACKEND_TLS:
    LOG(WARN) << opt << ": deprecated.  Use tls keyword in "
              << SHRPX_OPT_BACKEND << " instead.";
    return 0;
  case SHRPX_OPTID_TLS_SESSION_CACHE_MEMCACHED_TLS:
    LOG(WARN) << opt << ": deprecated.  Use tls keyword in "
              << SHRPX_OPT_TLS_SESSION_CACHE_MEMCACHED;
    return 0;
  case SHRPX_OPTID_TLS_SESSION_CACHE_MEMCACHED_CERT_FILE:
    config->tls.session_cache.memcached.cert_file =
        make_string_ref(config->balloc, optarg);

    return 0;
  case SHRPX_OPTID_TLS_SESSION_CACHE_MEMCACHED_PRIVATE_KEY_FILE:
    config->tls.session_cache.memcached.private_key_file =
        make_string_ref(config->balloc, optarg);

    return 0;
  case SHRPX_OPTID_TLS_TICKET_KEY_MEMCACHED_TLS:
    LOG(WARN) << opt << ": deprecated.  Use tls keyword in "
              << SHRPX_OPT_TLS_TICKET_KEY_MEMCACHED;
    return 0;
  case SHRPX_OPTID_TLS_TICKET_KEY_MEMCACHED_CERT_FILE:
    config->tls.ticket.memcached.cert_file =
        make_string_ref(config->balloc, optarg);

    return 0;
  case SHRPX_OPTID_TLS_TICKET_KEY_MEMCACHED_PRIVATE_KEY_FILE:
    config->tls.ticket.memcached.private_key_file =
        make_string_ref(config->balloc, optarg);

    return 0;
  case SHRPX_OPTID_TLS_TICKET_KEY_MEMCACHED_ADDRESS_FAMILY:
    return parse_address_family(&config->tls.ticket.memcached.family, opt,
                                optarg);
  case SHRPX_OPTID_TLS_SESSION_CACHE_MEMCACHED_ADDRESS_FAMILY:
    return parse_address_family(&config->tls.session_cache.memcached.family,
                                opt, optarg);
  case SHRPX_OPTID_BACKEND_ADDRESS_FAMILY:
    return parse_address_family(&config->conn.downstream->family, opt, optarg);
  case SHRPX_OPTID_FRONTEND_HTTP2_MAX_CONCURRENT_STREAMS:
    return parse_uint(&config->http2.upstream.max_concurrent_streams, opt,
                      optarg);
  case SHRPX_OPTID_BACKEND_HTTP2_MAX_CONCURRENT_STREAMS:
    return parse_uint(&config->http2.downstream.max_concurrent_streams, opt,
                      optarg);
  case SHRPX_OPTID_ERROR_PAGE:
    return parse_error_page(config->http.error_pages, opt, optarg);
  case SHRPX_OPTID_NO_KQUEUE:
    if ((ev_supported_backends() & EVBACKEND_KQUEUE) == 0) {
      LOG(WARN) << opt << ": kqueue is not supported on this platform";
      return 0;
    }

    config->ev_loop_flags = ev_recommended_backends() & ~EVBACKEND_KQUEUE;

    return 0;
  case SHRPX_OPTID_FRONTEND_HTTP2_SETTINGS_TIMEOUT:
    return parse_duration(&config->http2.upstream.timeout.settings, opt,
                          optarg);
  case SHRPX_OPTID_BACKEND_HTTP2_SETTINGS_TIMEOUT:
    return parse_duration(&config->http2.downstream.timeout.settings, opt,
                          optarg);
  case SHRPX_OPTID_API_MAX_REQUEST_BODY:
    return parse_uint_with_unit(&config->api.max_request_body, opt, optarg);
  case SHRPX_OPTID_BACKEND_MAX_BACKOFF:
    return parse_duration(&config->conn.downstream->timeout.max_backoff, opt,
                          optarg);
  case SHRPX_OPTID_SERVER_NAME:
    config->http.server_name = make_string_ref(config->balloc, optarg);

    return 0;
  case SHRPX_OPTID_NO_SERVER_REWRITE:
    config->http.no_server_rewrite = util::strieq("yes"_sr, optarg);

    return 0;
  case SHRPX_OPTID_FRONTEND_HTTP2_OPTIMIZE_WRITE_BUFFER_SIZE:
    config->http2.upstream.optimize_write_buffer_size =
        util::strieq("yes"_sr, optarg);

    return 0;
  case SHRPX_OPTID_FRONTEND_HTTP2_OPTIMIZE_WINDOW_SIZE:
    config->http2.upstream.optimize_window_size =
        util::strieq("yes"_sr, optarg);

    return 0;
  case SHRPX_OPTID_FRONTEND_HTTP2_WINDOW_SIZE:
    if (parse_uint_with_unit(&config->http2.upstream.window_size, opt,
                             optarg) != 0) {
      return -1;
    }

    return 0;
  case SHRPX_OPTID_FRONTEND_HTTP2_CONNECTION_WINDOW_SIZE:
    if (parse_uint_with_unit(&config->http2.upstream.connection_window_size,
                             opt, optarg) != 0) {
      return -1;
    }

    return 0;
  case SHRPX_OPTID_BACKEND_HTTP2_WINDOW_SIZE:
    if (parse_uint_with_unit(&config->http2.downstream.window_size, opt,
                             optarg) != 0) {
      return -1;
    }

    return 0;
  case SHRPX_OPTID_BACKEND_HTTP2_CONNECTION_WINDOW_SIZE:
    if (parse_uint_with_unit(&config->http2.downstream.connection_window_size,
                             opt, optarg) != 0) {
      return -1;
    }

    return 0;
  case SHRPX_OPTID_FRONTEND_HTTP2_ENCODER_DYNAMIC_TABLE_SIZE:
    if (parse_uint_with_unit(&config->http2.upstream.encoder_dynamic_table_size,
                             opt, optarg) != 0) {
      return -1;
    }

    nghttp2_option_set_max_deflate_dynamic_table_size(
        config->http2.upstream.option,
        config->http2.upstream.encoder_dynamic_table_size);
    nghttp2_option_set_max_deflate_dynamic_table_size(
        config->http2.upstream.alt_mode_option,
        config->http2.upstream.encoder_dynamic_table_size);

    return 0;
  case SHRPX_OPTID_FRONTEND_HTTP2_DECODER_DYNAMIC_TABLE_SIZE:
    return parse_uint_with_unit(
        &config->http2.upstream.decoder_dynamic_table_size, opt, optarg);
  case SHRPX_OPTID_BACKEND_HTTP2_ENCODER_DYNAMIC_TABLE_SIZE:
    if (parse_uint_with_unit(
            &config->http2.downstream.encoder_dynamic_table_size, opt,
            optarg) != 0) {
      return -1;
    }

    nghttp2_option_set_max_deflate_dynamic_table_size(
        config->http2.downstream.option,
        config->http2.downstream.encoder_dynamic_table_size);

    return 0;
  case SHRPX_OPTID_BACKEND_HTTP2_DECODER_DYNAMIC_TABLE_SIZE:
    return parse_uint_with_unit(
        &config->http2.downstream.decoder_dynamic_table_size, opt, optarg);
  case SHRPX_OPTID_ECDH_CURVES:
    config->tls.ecdh_curves = make_string_ref(config->balloc, optarg);
    return 0;
  case SHRPX_OPTID_TLS_SCT_DIR:
#if defined(NGHTTP2_GENUINE_OPENSSL) || defined(NGHTTP2_OPENSSL_IS_BORINGSSL)
    return read_tls_sct_from_dir(config->tls.sct_data, opt, optarg);
#else  // !NGHTTP2_GENUINE_OPENSSL && !NGHTTP2_OPENSSL_IS_BORINGSSL
    LOG(WARN)
        << opt
        << ": ignored because underlying TLS library does not support SCT";
    return 0;
#endif // !NGHTTP2_GENUINE_OPENSSL && !NGHTTP2_OPENSSL_IS_BORINGSSL
  case SHRPX_OPTID_DNS_CACHE_TIMEOUT:
    return parse_duration(&config->dns.timeout.cache, opt, optarg);
  case SHRPX_OPTID_DNS_LOOKUP_TIMEOUT:
    return parse_duration(&config->dns.timeout.lookup, opt, optarg);
  case SHRPX_OPTID_DNS_MAX_TRY: {
    int n;
    if (parse_uint(&n, opt, optarg) != 0) {
      return -1;
    }

    if (n > 5) {
      LOG(ERROR) << opt << ": must be smaller than or equal to 5";
      return -1;
    }

    config->dns.max_try = n;
    return 0;
  }
  case SHRPX_OPTID_FRONTEND_KEEP_ALIVE_TIMEOUT:
    return parse_duration(&config->conn.upstream.timeout.idle, opt, optarg);
  case SHRPX_OPTID_PSK_SECRETS:
#ifndef OPENSSL_NO_PSK
    return parse_psk_secrets(config, optarg);
#else  // OPENSSL_NO_PSK
    LOG(WARN)
        << opt
        << ": ignored because underlying TLS library does not support PSK";
    return 0;
#endif // OPENSSL_NO_PSK
  case SHRPX_OPTID_CLIENT_PSK_SECRETS:
#ifndef OPENSSL_NO_PSK
    return parse_client_psk_secrets(config, optarg);
#else  // OPENSSL_NO_PSK
    LOG(WARN)
        << opt
        << ": ignored because underlying TLS library does not support PSK";
    return 0;
#endif // OPENSSL_NO_PSK
  case SHRPX_OPTID_CLIENT_NO_HTTP2_CIPHER_BLACK_LIST:
    LOG(WARN) << opt << ": deprecated.  Use "
              << SHRPX_OPT_CLIENT_NO_HTTP2_CIPHER_BLOCK_LIST << " instead.";
    // fall through
  case SHRPX_OPTID_CLIENT_NO_HTTP2_CIPHER_BLOCK_LIST:
    config->tls.client.no_http2_cipher_block_list =
        util::strieq("yes"_sr, optarg);

    return 0;
  case SHRPX_OPTID_CLIENT_CIPHERS:
    config->tls.client.ciphers = make_string_ref(config->balloc, optarg);

    return 0;
  case SHRPX_OPTID_TLS13_CLIENT_CIPHERS:
    config->tls.client.tls13_ciphers = make_string_ref(config->balloc, optarg);

    return 0;
  case SHRPX_OPTID_ACCESSLOG_WRITE_EARLY:
    config->logging.access.write_early = util::strieq("yes"_sr, optarg);

    return 0;
  case SHRPX_OPTID_TLS_MIN_PROTO_VERSION:
    return parse_tls_proto_version(config->tls.min_proto_version, opt, optarg);
  case SHRPX_OPTID_TLS_MAX_PROTO_VERSION:
    return parse_tls_proto_version(config->tls.max_proto_version, opt, optarg);
  case SHRPX_OPTID_REDIRECT_HTTPS_PORT: {
    auto n = util::parse_uint(optarg);
    if (!n || n < 0 || n > 65535) {
      LOG(ERROR) << opt
                 << ": bad value.  Specify an integer in the range [0, "
                    "65535], inclusive";
      return -1;
    }
    config->http.redirect_https_port = make_string_ref(config->balloc, optarg);
    return 0;
  }
  case SHRPX_OPTID_FRONTEND_MAX_REQUESTS:
    return parse_uint(&config->http.max_requests, opt, optarg);
  case SHRPX_OPTID_SINGLE_THREAD:
    config->single_thread = util::strieq("yes"_sr, optarg);

    return 0;
  case SHRPX_OPTID_SINGLE_PROCESS:
    config->single_process = util::strieq("yes"_sr, optarg);

    return 0;
  case SHRPX_OPTID_NO_ADD_X_FORWARDED_PROTO:
    config->http.xfp.add = !util::strieq("yes"_sr, optarg);

    return 0;
  case SHRPX_OPTID_NO_STRIP_INCOMING_X_FORWARDED_PROTO:
    config->http.xfp.strip_incoming = !util::strieq("yes"_sr, optarg);

    return 0;
  case SHRPX_OPTID_OCSP_STARTUP:
    config->tls.ocsp.startup = util::strieq("yes"_sr, optarg);

    return 0;
  case SHRPX_OPTID_NO_VERIFY_OCSP:
    config->tls.ocsp.no_verify = util::strieq("yes"_sr, optarg);

    return 0;
  case SHRPX_OPTID_VERIFY_CLIENT_TOLERATE_EXPIRED:
    config->tls.client_verify.tolerate_expired = util::strieq("yes"_sr, optarg);

    return 0;
  case SHRPX_OPTID_IGNORE_PER_PATTERN_MRUBY_ERROR:
    config->ignore_per_pattern_mruby_error = util::strieq("yes"_sr, optarg);

    return 0;
  case SHRPX_OPTID_TLS_NO_POSTPONE_EARLY_DATA:
    config->tls.no_postpone_early_data = util::strieq("yes"_sr, optarg);

    return 0;
  case SHRPX_OPTID_TLS_MAX_EARLY_DATA: {
    return parse_uint_with_unit(&config->tls.max_early_data, opt, optarg);
  }
  case SHRPX_OPTID_NO_STRIP_INCOMING_EARLY_DATA:
    config->http.early_data.strip_incoming = !util::strieq("yes"_sr, optarg);

    return 0;
  case SHRPX_OPTID_QUIC_BPF_PROGRAM_FILE:
#ifdef ENABLE_HTTP3
    config->quic.bpf.prog_file = make_string_ref(config->balloc, optarg);
#endif // ENABLE_HTTP3

    return 0;
  case SHRPX_OPTID_NO_QUIC_BPF:
#ifdef ENABLE_HTTP3
    config->quic.bpf.disabled = util::strieq("yes"_sr, optarg);
#endif // ENABLE_HTTP3

    return 0;
  case SHRPX_OPTID_HTTP2_ALTSVC: {
    AltSvc altsvc{};

    if (parse_altsvc(altsvc, opt, optarg) != 0) {
      return -1;
    }

    config->http.http2_altsvcs.push_back(std::move(altsvc));

    return 0;
  }
  case SHRPX_OPTID_FRONTEND_HTTP3_READ_TIMEOUT:
    LOG(WARN) << opt << ": deprecated.  Use frontend-http3-idle-timeout";
    // fall through
  case SHRPX_OPTID_FRONTEND_HTTP3_IDLE_TIMEOUT:
#ifdef ENABLE_HTTP3
    return parse_duration(&config->conn.upstream.timeout.http3_idle, opt,
                          optarg);
#else  // !ENABLE_HTTP3
    return 0;
#endif // !ENABLE_HTTP3
  case SHRPX_OPTID_FRONTEND_QUIC_IDLE_TIMEOUT:
#ifdef ENABLE_HTTP3
    return parse_duration(&config->quic.upstream.timeout.idle, opt, optarg);
#else  // !ENABLE_HTTP3
    return 0;
#endif // !ENABLE_HTTP3
  case SHRPX_OPTID_FRONTEND_QUIC_DEBUG_LOG:
#ifdef ENABLE_HTTP3
    config->quic.upstream.debug.log = util::strieq("yes"_sr, optarg);
#endif // ENABLE_HTTP3

    return 0;
  case SHRPX_OPTID_FRONTEND_HTTP3_WINDOW_SIZE:
#ifdef ENABLE_HTTP3
    if (parse_uint_with_unit(&config->http3.upstream.window_size, opt,
                             optarg) != 0) {
      return -1;
    }
#endif // ENABLE_HTTP3

    return 0;
  case SHRPX_OPTID_FRONTEND_HTTP3_CONNECTION_WINDOW_SIZE:
#ifdef ENABLE_HTTP3
    if (parse_uint_with_unit(&config->http3.upstream.connection_window_size,
                             opt, optarg) != 0) {
      return -1;
    }
#endif // ENABLE_HTTP3

    return 0;
  case SHRPX_OPTID_FRONTEND_HTTP3_MAX_WINDOW_SIZE:
#ifdef ENABLE_HTTP3
    if (parse_uint_with_unit(&config->http3.upstream.max_window_size, opt,
                             optarg) != 0) {
      return -1;
    }
#endif // ENABLE_HTTP3

    return 0;
  case SHRPX_OPTID_FRONTEND_HTTP3_MAX_CONNECTION_WINDOW_SIZE:
#ifdef ENABLE_HTTP3
    if (parse_uint_with_unit(&config->http3.upstream.max_connection_window_size,
                             opt, optarg) != 0) {
      return -1;
    }
#endif // ENABLE_HTTP3

    return 0;
  case SHRPX_OPTID_FRONTEND_HTTP3_MAX_CONCURRENT_STREAMS:
#ifdef ENABLE_HTTP3
    return parse_uint(&config->http3.upstream.max_concurrent_streams, opt,
                      optarg);
#else  // !ENABLE_HTTP3
    return 0;
#endif // !ENABLE_HTTP3
  case SHRPX_OPTID_FRONTEND_QUIC_EARLY_DATA:
#ifdef ENABLE_HTTP3
    config->quic.upstream.early_data = util::strieq("yes"_sr, optarg);
#endif // ENABLE_HTTP3

    return 0;
  case SHRPX_OPTID_FRONTEND_QUIC_QLOG_DIR:
#ifdef ENABLE_HTTP3
    config->quic.upstream.qlog.dir = make_string_ref(config->balloc, optarg);
#endif // ENABLE_HTTP3

    return 0;
  case SHRPX_OPTID_FRONTEND_QUIC_REQUIRE_TOKEN:
#ifdef ENABLE_HTTP3
    config->quic.upstream.require_token = util::strieq("yes"_sr, optarg);
#endif // ENABLE_HTTP3

    return 0;
  case SHRPX_OPTID_FRONTEND_QUIC_CONGESTION_CONTROLLER:
#ifdef ENABLE_HTTP3
    if (util::strieq("cubic"_sr, optarg)) {
      config->quic.upstream.congestion_controller = NGTCP2_CC_ALGO_CUBIC;
    } else if (util::strieq("bbr"_sr, optarg)) {
      config->quic.upstream.congestion_controller = NGTCP2_CC_ALGO_BBR;
    } else {
      LOG(ERROR) << opt << ": must be either cubic or bbr";
      return -1;
    }
#endif // ENABLE_HTTP3

    return 0;
  case SHRPX_OPTID_QUIC_SERVER_ID:
#ifdef ENABLE_HTTP3
    if (optarg.size() != sizeof(config->quic.server_id) * 2 ||
        !util::is_hex_string(optarg)) {
      LOG(ERROR) << opt << ": must be a hex-string";
      return -1;
    }
    util::decode_hex(reinterpret_cast<uint8_t *>(&config->quic.server_id),
                     optarg);
#endif // ENABLE_HTTP3

    return 0;
  case SHRPX_OPTID_FRONTEND_QUIC_SECRET_FILE:
#ifdef ENABLE_HTTP3
    config->quic.upstream.secret_file = make_string_ref(config->balloc, optarg);
#endif // ENABLE_HTTP3

    return 0;
  case SHRPX_OPTID_RLIMIT_MEMLOCK: {
    int n;

    if (parse_uint(&n, opt, optarg) != 0) {
      return -1;
    }

    if (n < 0) {
      LOG(ERROR) << opt << ": specify the integer more than or equal to 0";

      return -1;
    }

    config->rlimit_memlock = n;

    return 0;
  }
  case SHRPX_OPTID_MAX_WORKER_PROCESSES:
    return parse_uint(&config->max_worker_processes, opt, optarg);
  case SHRPX_OPTID_WORKER_PROCESS_GRACE_SHUTDOWN_PERIOD:
    return parse_duration(&config->worker_process_grace_shutdown_period, opt,
                          optarg);
  case SHRPX_OPTID_FRONTEND_QUIC_INITIAL_RTT: {
#ifdef ENABLE_HTTP3
    return parse_duration(&config->quic.upstream.initial_rtt, opt, optarg);
#endif // ENABLE_HTTP3

    return 0;
  }
  case SHRPX_OPTID_REQUIRE_HTTP_SCHEME:
    config->http.require_http_scheme = util::strieq("yes"_sr, optarg);
    return 0;
  case SHRPX_OPTID_TLS_KTLS:
    config->tls.ktls = util::strieq("yes"_sr, optarg);
    return 0;
  case SHRPX_OPTID_NPN_LIST:
    LOG(WARN) << opt << ": deprecated.  Use alpn-list instead.";
    // fall through
  case SHRPX_OPTID_ALPN_LIST: {
    auto list = util::split_str(optarg, ',');
    config->tls.alpn_list.resize(list.size());
    for (size_t i = 0; i < list.size(); ++i) {
      config->tls.alpn_list[i] = make_string_ref(config->balloc, list[i]);
    }

    return 0;
  }
  case SHRPX_OPTID_CONF:
    LOG(WARN) << "conf: ignored";

    return 0;
  }

  LOG(ERROR) << "Unknown option: " << opt;

  return -1;
}

int load_config(Config *config, const char *filename,
                std::set<StringRef> &include_set,
                std::map<StringRef, size_t> &pattern_addr_indexer) {
  std::ifstream in(filename, std::ios::binary);
  if (!in) {
    LOG(ERROR) << "Could not open config file " << filename;
    return -1;
  }
  std::string line;
  int linenum = 0;
  while (std::getline(in, line)) {
    ++linenum;
    if (line.empty() || line[0] == '#') {
      continue;
    }
    auto eq = std::find(std::begin(line), std::end(line), '=');
    if (eq == std::end(line)) {
      LOG(ERROR) << "Bad configuration format in " << filename << " at line "
                 << linenum;
      return -1;
    }
    *eq = '\0';

    if (parse_config(config, StringRef{std::begin(line), eq},
                     StringRef{eq + 1, std::end(line)}, include_set,
                     pattern_addr_indexer) != 0) {
      return -1;
    }
  }
  return 0;
}

StringRef str_syslog_facility(int facility) {
  switch (facility) {
  case (LOG_AUTH):
    return "auth"_sr;
#ifdef LOG_AUTHPRIV
  case (LOG_AUTHPRIV):
    return "authpriv"_sr;
#endif // LOG_AUTHPRIV
  case (LOG_CRON):
    return "cron"_sr;
  case (LOG_DAEMON):
    return "daemon"_sr;
#ifdef LOG_FTP
  case (LOG_FTP):
    return "ftp"_sr;
#endif // LOG_FTP
  case (LOG_KERN):
    return "kern"_sr;
  case (LOG_LOCAL0):
    return "local0"_sr;
  case (LOG_LOCAL1):
    return "local1"_sr;
  case (LOG_LOCAL2):
    return "local2"_sr;
  case (LOG_LOCAL3):
    return "local3"_sr;
  case (LOG_LOCAL4):
    return "local4"_sr;
  case (LOG_LOCAL5):
    return "local5"_sr;
  case (LOG_LOCAL6):
    return "local6"_sr;
  case (LOG_LOCAL7):
    return "local7"_sr;
  case (LOG_LPR):
    return "lpr"_sr;
  case (LOG_MAIL):
    return "mail"_sr;
  case (LOG_SYSLOG):
    return "syslog"_sr;
  case (LOG_USER):
    return "user"_sr;
  case (LOG_UUCP):
    return "uucp"_sr;
  default:
    return "(unknown)"_sr;
  }
}

int int_syslog_facility(const StringRef &strfacility) {
  if (util::strieq("auth"_sr, strfacility)) {
    return LOG_AUTH;
  }

#ifdef LOG_AUTHPRIV
  if (util::strieq("authpriv"_sr, strfacility)) {
    return LOG_AUTHPRIV;
  }
#endif // LOG_AUTHPRIV

  if (util::strieq("cron"_sr, strfacility)) {
    return LOG_CRON;
  }

  if (util::strieq("daemon"_sr, strfacility)) {
    return LOG_DAEMON;
  }

#ifdef LOG_FTP
  if (util::strieq("ftp"_sr, strfacility)) {
    return LOG_FTP;
  }
#endif // LOG_FTP

  if (util::strieq("kern"_sr, strfacility)) {
    return LOG_KERN;
  }

  if (util::strieq("local0"_sr, strfacility)) {
    return LOG_LOCAL0;
  }

  if (util::strieq("local1"_sr, strfacility)) {
    return LOG_LOCAL1;
  }

  if (util::strieq("local2"_sr, strfacility)) {
    return LOG_LOCAL2;
  }

  if (util::strieq("local3"_sr, strfacility)) {
    return LOG_LOCAL3;
  }

  if (util::strieq("local4"_sr, strfacility)) {
    return LOG_LOCAL4;
  }

  if (util::strieq("local5"_sr, strfacility)) {
    return LOG_LOCAL5;
  }

  if (util::strieq("local6"_sr, strfacility)) {
    return LOG_LOCAL6;
  }

  if (util::strieq("local7"_sr, strfacility)) {
    return LOG_LOCAL7;
  }

  if (util::strieq("lpr"_sr, strfacility)) {
    return LOG_LPR;
  }

  if (util::strieq("mail"_sr, strfacility)) {
    return LOG_MAIL;
  }

  if (util::strieq("news"_sr, strfacility)) {
    return LOG_NEWS;
  }

  if (util::strieq("syslog"_sr, strfacility)) {
    return LOG_SYSLOG;
  }

  if (util::strieq("user"_sr, strfacility)) {
    return LOG_USER;
  }

  if (util::strieq("uucp"_sr, strfacility)) {
    return LOG_UUCP;
  }

  return -1;
}

StringRef strproto(Proto proto) {
  switch (proto) {
  case Proto::NONE:
    return "none"_sr;
  case Proto::HTTP1:
    return "http/1.1"_sr;
  case Proto::HTTP2:
    return "h2"_sr;
  case Proto::HTTP3:
    return "h3"_sr;
  case Proto::MEMCACHED:
    return "memcached"_sr;
  }

  // gcc needs this.
  assert(0);
  abort();
}

namespace {
// Consistent hashing method described in
// https://github.com/RJ/ketama.  Generate 160 32-bit hashes per |s|,
// which is usually backend address.  The each hash is associated to
// index of backend address.  When all hashes for every backend
// address are calculated, sort it in ascending order of hash.  To
// choose the index, compute 32-bit hash based on client IP address,
// and do lower bound search in the array. The returned index is the
// backend to use.
int compute_affinity_hash(std::vector<AffinityHash> &res, size_t idx,
                          const StringRef &s) {
  int rv;
  std::array<uint8_t, 32> buf;

  for (auto i = 0; i < 20; ++i) {
    auto t = std::string{s};
    t += i;

    rv = util::sha256(buf.data(), StringRef{t});
    if (rv != 0) {
      return -1;
    }

    for (int i = 0; i < 8; ++i) {
      auto h = (static_cast<uint32_t>(buf[4 * i]) << 24) |
               (static_cast<uint32_t>(buf[4 * i + 1]) << 16) |
               (static_cast<uint32_t>(buf[4 * i + 2]) << 8) |
               static_cast<uint32_t>(buf[4 * i + 3]);

      res.emplace_back(idx, h);
    }
  }

  return 0;
}
} // namespace

// Configures the following member in |config|:
// conn.downstream_router, conn.downstream.addr_groups,
// conn.downstream.addr_group_catch_all.
int configure_downstream_group(Config *config, bool http2_proxy,
                               bool numeric_addr_only,
                               const TLSConfig &tlsconf) {
  int rv;

  auto &downstreamconf = *config->conn.downstream;
  auto &addr_groups = downstreamconf.addr_groups;
  auto &routerconf = downstreamconf.router;
  auto &router = routerconf.router;

  if (addr_groups.empty()) {
    DownstreamAddrConfig addr{};
    addr.host = DEFAULT_DOWNSTREAM_HOST;
    addr.port = DEFAULT_DOWNSTREAM_PORT;
    addr.proto = Proto::HTTP1;
    addr.weight = 1;
    addr.group_weight = 1;

    DownstreamAddrGroupConfig g("/"_sr);
    g.addrs.push_back(std::move(addr));
    router.add_route(g.pattern, addr_groups.size());
    addr_groups.push_back(std::move(g));
  }

  // backward compatibility: override all SNI fields with the option
  // value --backend-tls-sni-field
  if (!tlsconf.backend_sni_name.empty()) {
    auto &sni = tlsconf.backend_sni_name;
    for (auto &addr_group : addr_groups) {
      for (auto &addr : addr_group.addrs) {
        addr.sni = sni;
      }
    }
  }

  if (LOG_ENABLED(INFO)) {
    LOG(INFO) << "Resolving backend address";
  }

  ssize_t catch_all_group = -1;
  for (size_t i = 0; i < addr_groups.size(); ++i) {
    auto &g = addr_groups[i];
    if (g.pattern == "/"_sr) {
      catch_all_group = i;
    }
    if (LOG_ENABLED(INFO)) {
      LOG(INFO) << "Host-path pattern: group " << i << ": '" << g.pattern
                << "'";
      for (auto &addr : g.addrs) {
        LOG(INFO) << "group " << i << " -> " << addr.host.data()
                  << (addr.host_unix ? "" : ":" + util::utos(addr.port))
                  << ", proto=" << strproto(addr.proto)
                  << (addr.tls ? ", tls" : "");
      }
    }
#ifdef HAVE_MRUBY
    // Try compile mruby script and catch compile error early.
    if (!g.mruby_file.empty()) {
      if (mruby::create_mruby_context(g.mruby_file) == nullptr) {
        LOG(config->ignore_per_pattern_mruby_error ? ERROR : FATAL)
            << "backend: Could not compile mruby file for pattern "
            << g.pattern;
        if (!config->ignore_per_pattern_mruby_error) {
          return -1;
        }
        g.mruby_file = StringRef{};
      }
    }
#endif // HAVE_MRUBY
  }

#ifdef HAVE_MRUBY
  // Try compile mruby script (--mruby-file) here to catch compile
  // error early.
  if (!config->mruby_file.empty()) {
    if (mruby::create_mruby_context(config->mruby_file) == nullptr) {
      LOG(FATAL) << "mruby-file: Could not compile mruby file";
      return -1;
    }
  }
#endif // HAVE_MRUBY

  if (catch_all_group == -1) {
    LOG(FATAL) << "backend: No catch-all backend address is configured";
    return -1;
  }

  downstreamconf.addr_group_catch_all = catch_all_group;

  if (LOG_ENABLED(INFO)) {
    LOG(INFO) << "Catch-all pattern is group " << catch_all_group;
  }

  auto resolve_flags = numeric_addr_only ? AI_NUMERICHOST | AI_NUMERICSERV : 0;

  std::array<char, util::max_hostport> hostport_buf;

  for (auto &g : addr_groups) {
    std::unordered_map<StringRef, uint32_t> wgchk;
    for (auto &addr : g.addrs) {
      if (addr.group_weight) {
        auto it = wgchk.find(addr.group);
        if (it == std::end(wgchk)) {
          wgchk.emplace(addr.group, addr.group_weight);
        } else if ((*it).second != addr.group_weight) {
          LOG(FATAL) << "backend: inconsistent group-weight for a single group";
          return -1;
        }
      }

      if (addr.host_unix) {
        // for AF_UNIX socket, we use "localhost" as host for backend
        // hostport.  This is used as Host header field to backend and
        // not going to be passed to any syscalls.
        addr.hostport = "localhost"_sr;

        auto path = addr.host.data();
        auto pathlen = addr.host.size();

        if (pathlen + 1 > sizeof(addr.addr.su.un.sun_path)) {
          LOG(FATAL) << "UNIX domain socket path " << path << " is too long > "
                     << sizeof(addr.addr.su.un.sun_path);
          return -1;
        }

        if (LOG_ENABLED(INFO)) {
          LOG(INFO) << "Use UNIX domain socket path " << path
                    << " for backend connection";
        }

        addr.addr.su.un.sun_family = AF_UNIX;
        // copy path including terminal NULL
        std::copy_n(path, pathlen + 1, addr.addr.su.un.sun_path);
        addr.addr.len = sizeof(addr.addr.su.un);

        continue;
      }

      addr.hostport =
          util::make_http_hostport(downstreamconf.balloc, addr.host, addr.port);

      auto hostport =
          util::make_hostport(std::begin(hostport_buf), addr.host, addr.port);

      if (!addr.dns) {
        if (resolve_hostname(&addr.addr, addr.host.data(), addr.port,
                             downstreamconf.family, resolve_flags) == -1) {
          LOG(FATAL) << "Resolving backend address failed: " << hostport;
          return -1;
        }

        if (LOG_ENABLED(INFO)) {
          LOG(INFO) << "Resolved backend address: " << hostport << " -> "
                    << util::to_numeric_addr(&addr.addr);
        }
      } else {
        LOG(INFO) << "Resolving backend address " << hostport
                  << " takes place dynamically";
      }
    }

    for (auto &addr : g.addrs) {
      if (addr.group_weight == 0) {
        auto it = wgchk.find(addr.group);
        if (it == std::end(wgchk)) {
          addr.group_weight = 1;
        } else {
          addr.group_weight = (*it).second;
        }
      }
    }

    if (g.affinity.type != SessionAffinity::NONE) {
      size_t idx = 0;
      for (auto &addr : g.addrs) {
        StringRef key;
        if (addr.dns) {
          if (addr.host_unix) {
            key = addr.host;
          } else {
            key = addr.hostport;
          }
        } else {
          auto p = reinterpret_cast<uint8_t *>(&addr.addr.su);
          key = StringRef{p, addr.addr.len};
        }
        rv = compute_affinity_hash(g.affinity_hash, idx, key);
        if (rv != 0) {
          return -1;
        }

        if (g.affinity.cookie.stickiness ==
            SessionAffinityCookieStickiness::STRICT) {
          addr.affinity_hash = util::hash32(key);
          g.affinity_hash_map.emplace(addr.affinity_hash, idx);
        }

        ++idx;
      }

      std::sort(std::begin(g.affinity_hash), std::end(g.affinity_hash),
                [](const AffinityHash &lhs, const AffinityHash &rhs) {
                  return lhs.hash < rhs.hash;
                });
    }

    auto &timeout = g.timeout;
    if (timeout.read < 1e-9) {
      timeout.read = downstreamconf.timeout.read;
    }
    if (timeout.write < 1e-9) {
      timeout.write = downstreamconf.timeout.write;
    }
  }

  return 0;
}

int resolve_hostname(Address *addr, const char *hostname, uint16_t port,
                     int family, int additional_flags) {
  int rv;

  auto service = util::utos(port);

  addrinfo hints{};
  hints.ai_family = family;
  hints.ai_socktype = SOCK_STREAM;
  hints.ai_flags |= additional_flags;
#ifdef AI_ADDRCONFIG
  hints.ai_flags |= AI_ADDRCONFIG;
#endif // AI_ADDRCONFIG
  addrinfo *res;

  rv = getaddrinfo(hostname, service.c_str(), &hints, &res);
#ifdef AI_ADDRCONFIG
  if (rv != 0) {
    // Retry without AI_ADDRCONFIG
    hints.ai_flags &= ~AI_ADDRCONFIG;
    rv = getaddrinfo(hostname, service.c_str(), &hints, &res);
  }
#endif // AI_ADDRCONFIG
  if (rv != 0) {
    LOG(FATAL) << "Unable to resolve address for " << hostname << ": "
               << gai_strerror(rv);
    return -1;
  }

  auto res_d = defer(freeaddrinfo, res);

  char host[NI_MAXHOST];
  rv = getnameinfo(res->ai_addr, res->ai_addrlen, host, sizeof(host), nullptr,
                   0, NI_NUMERICHOST);
  if (rv != 0) {
    LOG(FATAL) << "Address resolution for " << hostname
               << " failed: " << gai_strerror(rv);

    return -1;
  }

  if (LOG_ENABLED(INFO)) {
    LOG(INFO) << "Address resolution for " << hostname
              << " succeeded: " << host;
  }

  memcpy(&addr->su, res->ai_addr, res->ai_addrlen);
  addr->len = res->ai_addrlen;

  return 0;
}

#ifdef ENABLE_HTTP3
QUICKeyingMaterial::QUICKeyingMaterial(QUICKeyingMaterial &&other) noexcept
    : cid_encryption_ctx{std::exchange(other.cid_encryption_ctx, nullptr)},
      cid_decryption_ctx{std::exchange(other.cid_decryption_ctx, nullptr)},
      reserved{other.reserved},
      secret{other.secret},
      salt{other.salt},
      cid_encryption_key{other.cid_encryption_key},
      id{other.id} {}

QUICKeyingMaterial::~QUICKeyingMaterial() noexcept {
  if (cid_encryption_ctx) {
    EVP_CIPHER_CTX_free(cid_encryption_ctx);
  }

  if (cid_decryption_ctx) {
    EVP_CIPHER_CTX_free(cid_decryption_ctx);
  }
}

QUICKeyingMaterial &
QUICKeyingMaterial::operator=(QUICKeyingMaterial &&other) noexcept {
  cid_encryption_ctx = std::exchange(other.cid_encryption_ctx, nullptr);
  cid_decryption_ctx = std::exchange(other.cid_decryption_ctx, nullptr);
  reserved = other.reserved;
  secret = other.secret;
  salt = other.salt;
  cid_encryption_key = other.cid_encryption_key;
  id = other.id;

  return *this;
}
#endif // ENABLE_HTTP3

} // namespace shrpx
