// Copyright (c) 2019 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "quic/core/crypto/tls_server_connection.h"

#include "absl/strings/string_view.h"
#include "third_party/boringssl/src/include/openssl/ssl.h"
#include "quic/core/crypto/proof_source.h"
#include "quic/platform/api/quic_flag_utils.h"
#include "quic/platform/api/quic_flags.h"

namespace quic {

TlsServerConnection::TlsServerConnection(SSL_CTX* ssl_ctx, Delegate* delegate)
    : TlsConnection(ssl_ctx, delegate->ConnectionDelegate()),
      delegate_(delegate) {}

// static
bssl::UniquePtr<SSL_CTX> TlsServerConnection::CreateSslCtx(
    ProofSource* proof_source) {
  bssl::UniquePtr<SSL_CTX> ssl_ctx =
      TlsConnection::CreateSslCtx(SSL_VERIFY_NONE);
  SSL_CTX_set_tlsext_servername_callback(ssl_ctx.get(),
                                         &TlsExtServernameCallback);
  SSL_CTX_set_alpn_select_cb(ssl_ctx.get(), &SelectAlpnCallback, nullptr);
  // We don't actually need the TicketCrypter here, but we need to know
  // whether it's set.
  if (proof_source->GetTicketCrypter()) {
    QUIC_RESTART_FLAG_COUNT_N(quic_session_tickets_always_enabled, 1, 3);
    SSL_CTX_set_ticket_aead_method(ssl_ctx.get(),
                                   &TlsServerConnection::kSessionTicketMethod);
  } else if (!GetQuicRestartFlag(quic_session_tickets_always_enabled)) {
    QUIC_RESTART_FLAG_COUNT_N(quic_session_tickets_always_enabled, 2, 3);
    SSL_CTX_set_options(ssl_ctx.get(), SSL_OP_NO_TICKET);
  } else {
    QUIC_RESTART_FLAG_COUNT_N(quic_session_tickets_always_enabled, 3, 3);
  }
  if (GetQuicRestartFlag(quic_enable_zero_rtt_for_tls_v2) &&
      (proof_source->GetTicketCrypter() ||
       GetQuicRestartFlag(quic_session_tickets_always_enabled))) {
    SSL_CTX_set_early_data_enabled(ssl_ctx.get(), 1);
  }
  SSL_CTX_set_select_certificate_cb(
      ssl_ctx.get(), &TlsServerConnection::EarlySelectCertCallback);
  if (GetQuicRestartFlag(quic_tls_prefer_server_cipher_and_curve_list)) {
    SSL_CTX_set_options(ssl_ctx.get(), SSL_OP_CIPHER_SERVER_PREFERENCE);
  }
  return ssl_ctx;
}

void TlsServerConnection::SetCertChain(
    const std::vector<CRYPTO_BUFFER*>& cert_chain) {
  SSL_set_chain_and_key(ssl(), cert_chain.data(), cert_chain.size(), nullptr,
                        &TlsServerConnection::kPrivateKeyMethod);
}

const SSL_PRIVATE_KEY_METHOD TlsServerConnection::kPrivateKeyMethod{
    &TlsServerConnection::PrivateKeySign,
    nullptr,  // decrypt
    &TlsServerConnection::PrivateKeyComplete,
};

// static
TlsServerConnection* TlsServerConnection::ConnectionFromSsl(SSL* ssl) {
  return static_cast<TlsServerConnection*>(
      TlsConnection::ConnectionFromSsl(ssl));
}

// static
ssl_select_cert_result_t TlsServerConnection::EarlySelectCertCallback(
    const SSL_CLIENT_HELLO* client_hello) {
  return ConnectionFromSsl(client_hello->ssl)
      ->delegate_->EarlySelectCertCallback(client_hello);
}

// static
int TlsServerConnection::TlsExtServernameCallback(SSL* ssl,
                                                  int* out_alert,
                                                  void* /*arg*/) {
  return ConnectionFromSsl(ssl)->delegate_->TlsExtServernameCallback(out_alert);
}

// static
int TlsServerConnection::SelectAlpnCallback(SSL* ssl,
                                            const uint8_t** out,
                                            uint8_t* out_len,
                                            const uint8_t* in,
                                            unsigned in_len,
                                            void* /*arg*/) {
  return ConnectionFromSsl(ssl)->delegate_->SelectAlpn(out, out_len, in,
                                                       in_len);
}

// static
ssl_private_key_result_t TlsServerConnection::PrivateKeySign(SSL* ssl,
                                                             uint8_t* out,
                                                             size_t* out_len,
                                                             size_t max_out,
                                                             uint16_t sig_alg,
                                                             const uint8_t* in,
                                                             size_t in_len) {
  return ConnectionFromSsl(ssl)->delegate_->PrivateKeySign(
      out, out_len, max_out, sig_alg,
      absl::string_view(reinterpret_cast<const char*>(in), in_len));
}

// static
ssl_private_key_result_t TlsServerConnection::PrivateKeyComplete(
    SSL* ssl,
    uint8_t* out,
    size_t* out_len,
    size_t max_out) {
  return ConnectionFromSsl(ssl)->delegate_->PrivateKeyComplete(out, out_len,
                                                               max_out);
}

// static
const SSL_TICKET_AEAD_METHOD TlsServerConnection::kSessionTicketMethod{
    TlsServerConnection::SessionTicketMaxOverhead,
    TlsServerConnection::SessionTicketSeal,
    TlsServerConnection::SessionTicketOpen,
};

// static
size_t TlsServerConnection::SessionTicketMaxOverhead(SSL* ssl) {
  return ConnectionFromSsl(ssl)->delegate_->SessionTicketMaxOverhead();
}

// static
int TlsServerConnection::SessionTicketSeal(SSL* ssl,
                                           uint8_t* out,
                                           size_t* out_len,
                                           size_t max_out_len,
                                           const uint8_t* in,
                                           size_t in_len) {
  return ConnectionFromSsl(ssl)->delegate_->SessionTicketSeal(
      out, out_len, max_out_len,
      absl::string_view(reinterpret_cast<const char*>(in), in_len));
}

// static
enum ssl_ticket_aead_result_t TlsServerConnection::SessionTicketOpen(
    SSL* ssl,
    uint8_t* out,
    size_t* out_len,
    size_t max_out_len,
    const uint8_t* in,
    size_t in_len) {
  return ConnectionFromSsl(ssl)->delegate_->SessionTicketOpen(
      out, out_len, max_out_len,
      absl::string_view(reinterpret_cast<const char*>(in), in_len));
}

}  // namespace quic