text: /*
   * Copyright 2016-2018 The OpenSSL Project Authors. All Rights Reserved.
   *
   * Licensed under the OpenSSL license (the "License").  You may not use
   * this file except in compliance with the License.  You can obtain a copy
   * in the file LICENSE in the source distribution or at
   * https://www.openssl.org/source/license.html
   */
  
  #include <string.h>
  
  #include <openssl/bio.h>
  #include <openssl/x509_vfy.h>
  #include <openssl/ssl.h>
  #ifndef OPENSSL_NO_SRP
  #include <openssl/srp.h>
  #endif
  
  #include "../ssl/ssl_locl.h"
  #include "internal/sockets.h"
  #include "internal/nelem.h"
  #include "handshake_helper.h"
  #include "testutil.h"
  
  #if !defined(OPENSSL_NO_SCTP) && !defined(OPENSSL_NO_SOCK)
  #include <netinet/sctp.h>
  #endif
  
  HANDSHAKE_RESULT *HANDSHAKE_RESULT_new(void)
  {
      HANDSHAKE_RESULT *ret;
  
      TEST_ptr(ret = OPENSSL_zalloc(sizeof(*ret)));
      return ret;
  }
  
  void HANDSHAKE_RESULT_free(HANDSHAKE_RESULT *result)
  {
      if (result == NULL)
          return;
      OPENSSL_free(result->client_npn_negotiated);
      OPENSSL_free(result->server_npn_negotiated);
      OPENSSL_free(result->client_alpn_negotiated);
      OPENSSL_free(result->server_alpn_negotiated);
      OPENSSL_free(result->result_session_ticket_app_data);
      sk_X509_NAME_pop_free(result->server_ca_names, X509_NAME_free);
      sk_X509_NAME_pop_free(result->client_ca_names, X509_NAME_free);
      OPENSSL_free(result->cipher);
      OPENSSL_free(result);
  }
  
  /*
   * Since there appears to be no way to extract the sent/received alert
   * from the SSL object directly, we use the info callback and stash
   * the result in ex_data.
   */
  typedef struct handshake_ex_data_st {
      int alert_sent;
      int num_fatal_alerts_sent;
      int alert_received;
      int session_ticket_do_not_call;
      ssl_servername_t servername;
  } HANDSHAKE_EX_DATA;
  
  typedef struct ctx_data_st {
      unsigned char *npn_protocols;
      size_t npn_protocols_len;
      unsigned char *alpn_protocols;
      size_t alpn_protocols_len;
      char *srp_user;
      char *srp_password;
      char *session_ticket_app_data;
  } CTX_DATA;
  
  /* |ctx_data| itself is stack-allocated. */
  static void ctx_data_free_data(CTX_DATA *ctx_data)
  {
      OPENSSL_free(ctx_data->npn_protocols);
      ctx_data->npn_protocols = NULL;
      OPENSSL_free(ctx_data->alpn_protocols);
      ctx_data->alpn_protocols = NULL;
      OPENSSL_free(ctx_data->srp_user);
      ctx_data->srp_user = NULL;
      OPENSSL_free(ctx_data->srp_password);
      ctx_data->srp_password = NULL;
      OPENSSL_free(ctx_data->session_ticket_app_data);
      ctx_data->session_ticket_app_data = NULL;
  }
  
  static int ex_data_idx;
  
  static void info_cb(const SSL *s, int where, int ret)
  {
      if (where & SSL_CB_ALERT) {
          HANDSHAKE_EX_DATA *ex_data =
              (HANDSHAKE_EX_DATA*)(SSL_get_ex_data(s, ex_data_idx));
          if (where & SSL_CB_WRITE) {
              ex_data->alert_sent = ret;
              if (strcmp(SSL_alert_type_string(ret), "F") == 0
                  || strcmp(SSL_alert_desc_string(ret), "CN") == 0)
                  ex_data->num_fatal_alerts_sent++;
          } else {
              ex_data->alert_received = ret;
          }
      }
  }
  
  /* Select the appropriate server CTX.
   * Returns SSL_TLSEXT_ERR_OK if a match was found.
   * If |ignore| is 1, returns SSL_TLSEXT_ERR_NOACK on mismatch.
   * Otherwise, returns SSL_TLSEXT_ERR_ALERT_FATAL on mismatch.
   * An empty SNI extension also returns SSL_TSLEXT_ERR_NOACK.
   */
  static int select_server_ctx(SSL *s, void *arg, int ignore)
  {
      const char *servername = SSL_get_servername(s, TLSEXT_NAMETYPE_host_name);
      HANDSHAKE_EX_DATA *ex_data =
          (HANDSHAKE_EX_DATA*)(SSL_get_ex_data(s, ex_data_idx));
  
      if (servername == NULL) {
          ex_data->servername = SSL_TEST_SERVERNAME_SERVER1;
          return SSL_TLSEXT_ERR_NOACK;
      }
  
      if (strcmp(servername, "server2") == 0) {
          SSL_CTX *new_ctx = (SSL_CTX*)arg;
          SSL_set_SSL_CTX(s, new_ctx);
          /*
           * Copy over all the SSL_CTX options - reasonable behavior
           * allows testing of cases where the options between two
           * contexts differ/conflict
           */
          SSL_clear_options(s, 0xFFFFFFFFL);
          SSL_set_options(s, SSL_CTX_get_options(new_ctx));
  
          ex_data->servername = SSL_TEST_SERVERNAME_SERVER2;
          return SSL_TLSEXT_ERR_OK;
      } else if (strcmp(servername, "server1") == 0) {
          ex_data->servername = SSL_TEST_SERVERNAME_SERVER1;
          return SSL_TLSEXT_ERR_OK;
      } else if (ignore) {
          ex_data->servername = SSL_TEST_SERVERNAME_SERVER1;
          return SSL_TLSEXT_ERR_NOACK;
      } else {
          /* Don't set an explicit alert, to test library defaults. */
          return SSL_TLSEXT_ERR_ALERT_FATAL;
      }
  }
  
  static int client_hello_select_server_ctx(SSL *s, void *arg, int ignore)
  {
      const char *servername;
      const unsigned char *p;
      size_t len, remaining;
      HANDSHAKE_EX_DATA *ex_data =
          (HANDSHAKE_EX_DATA*)(SSL_get_ex_data(s, ex_data_idx));
  
      /*
       * The server_name extension was given too much extensibility when it
       * was written, so parsing the normal case is a bit complex.
       */
      if (!SSL_client_hello_get0_ext(s, TLSEXT_TYPE_server_name, &p,
                                     &remaining) ||
          remaining <= 2)
          return 0;
      /* Extract the length of the supplied list of names. */
      len = (*(p++) << 8);
      len += *(p++);
      if (len + 2 != remaining)
          return 0;
      remaining = len;
      /*
       * The list in practice only has a single element, so we only consider
       * the first one.
       */
      if (remaining == 0 || *p++ != TLSEXT_NAMETYPE_host_name)
          return 0;
      remaining--;
      /* Now we can finally pull out the byte array with the actual hostname. */
      if (remaining <= 2)
          return 0;
      len = (*(p++) << 8);
      len += *(p++);
      if (len + 2 > remaining)
          return 0;
      remaining = len;
      servername = (const char *)p;
  
      if (len == strlen("server2") && strncmp(servername, "server2", len) == 0) {
          SSL_CTX *new_ctx = arg;
          SSL_set_SSL_CTX(s, new_ctx);
          /*
           * Copy over all the SSL_CTX options - reasonable behavior
           * allows testing of cases where the options between two
           * contexts differ/conflict
           */
          SSL_clear_options(s, 0xFFFFFFFFL);
          SSL_set_options(s, SSL_CTX_get_options(new_ctx));
  
          ex_data->servername = SSL_TEST_SERVERNAME_SERVER2;
          return 1;
      } else if (len == strlen("server1") &&
                 strncmp(servername, "server1", len) == 0) {
          ex_data->servername = SSL_TEST_SERVERNAME_SERVER1;
          return 1;
      } else if (ignore) {
          ex_data->servername = SSL_TEST_SERVERNAME_SERVER1;
          return 1;
      }
      return 0;
  }
  /*
   * (RFC 6066):
   *  If the server understood the ClientHello extension but
   *  does not recognize the server name, the server SHOULD take one of two
   *  actions: either abort the handshake by sending a fatal-level
   *  unrecognized_name(112) alert or continue the handshake.
   *
   * This behaviour is up to the application to configure; we test both
   * configurations to ensure the state machine propagates the result
   * correctly.
   */
  static int servername_ignore_cb(SSL *s, int *ad, void *arg)
  {
      return select_server_ctx(s, arg, 1);
  }
  
  static int servername_reject_cb(SSL *s, int *ad, void *arg)
  {
      return select_server_ctx(s, arg, 0);
  }
  
  static int client_hello_ignore_cb(SSL *s, int *al, void *arg)
  {
      if (!client_hello_select_server_ctx(s, arg, 1)) {
          *al = SSL_AD_UNRECOGNIZED_NAME;
          return SSL_CLIENT_HELLO_ERROR;
      }
      return SSL_CLIENT_HELLO_SUCCESS;
  }
  
  static int client_hello_reject_cb(SSL *s, int *al, void *arg)
  {
      if (!client_hello_select_server_ctx(s, arg, 0)) {
          *al = SSL_AD_UNRECOGNIZED_NAME;
          return SSL_CLIENT_HELLO_ERROR;
      }
      return SSL_CLIENT_HELLO_SUCCESS;
  }
  
  static int client_hello_nov12_cb(SSL *s, int *al, void *arg)
  {
      int ret;
      unsigned int v;
      const unsigned char *p;
  
      v = SSL_client_hello_get0_legacy_version(s);
      if (v > TLS1_2_VERSION || v < SSL3_VERSION) {
          *al = SSL_AD_PROTOCOL_VERSION;
          return SSL_CLIENT_HELLO_ERROR;
      }
      (void)SSL_client_hello_get0_session_id(s, &p);
      if (p == NULL ||
          SSL_client_hello_get0_random(s, &p) == 0 ||
          SSL_client_hello_get0_ciphers(s, &p) == 0 ||
          SSL_client_hello_get0_compression_methods(s, &p) == 0) {
          *al = SSL_AD_INTERNAL_ERROR;
          return SSL_CLIENT_HELLO_ERROR;
      }
      ret = client_hello_select_server_ctx(s, arg, 0);
      SSL_set_max_proto_version(s, TLS1_1_VERSION);
      if (!ret) {
          *al = SSL_AD_UNRECOGNIZED_NAME;
          return SSL_CLIENT_HELLO_ERROR;
      }
      return SSL_CLIENT_HELLO_SUCCESS;
  }
  
  static unsigned char dummy_ocsp_resp_good_val = 0xff;
  static unsigned char dummy_ocsp_resp_bad_val = 0xfe;
  
  static int server_ocsp_cb(SSL *s, void *arg)
  {
      unsigned char *resp;
  
      resp = OPENSSL_malloc(1);
      if (resp == NULL)
          return SSL_TLSEXT_ERR_ALERT_FATAL;
      /*
       * For the purposes of testing we just send back a dummy OCSP response
       */
      *resp = *(unsigned char *)arg;
      if (!SSL_set_tlsext_status_ocsp_resp(s, resp, 1))
          return SSL_TLSEXT_ERR_ALERT_FATAL;
  
      return SSL_TLSEXT_ERR_OK;
  }
  
  static int client_ocsp_cb(SSL *s, void *arg)
  {
      const unsigned char *resp;
      int len;
  
      len = SSL_get_tlsext_status_ocsp_resp(s, &resp);
      if (len != 1 || *resp != dummy_ocsp_resp_good_val)
          return 0;
  
      return 1;
  }
  
  static int verify_reject_cb(X509_STORE_CTX *ctx, void *arg) {
      X509_STORE_CTX_set_error(ctx, X509_V_ERR_APPLICATION_VERIFICATION);
      return 0;
  }
  
  static int verify_accept_cb(X509_STORE_CTX *ctx, void *arg) {
      return 1;
  }
  
  static int broken_session_ticket_cb(SSL *s, unsigned char *key_name, unsigned char *iv,
                                      EVP_CIPHER_CTX *ctx, HMAC_CTX *hctx, int enc)
  {
      return 0;
  }
  
  static int do_not_call_session_ticket_cb(SSL *s, unsigned char *key_name,
                                           unsigned char *iv,
                                           EVP_CIPHER_CTX *ctx,
                                           HMAC_CTX *hctx, int enc)
  {
      HANDSHAKE_EX_DATA *ex_data =
          (HANDSHAKE_EX_DATA*)(SSL_get_ex_data(s, ex_data_idx));
      ex_data->session_ticket_do_not_call = 1;
      return 0;
  }
  
  /* Parse the comma-separated list into TLS format. */
  static int parse_protos(const char *protos, unsigned char **out, size_t *outlen)
  {
      size_t len, i, prefix;
  
      len = strlen(protos);
  
      /* Should never have reuse. */
      if (!TEST_ptr_null(*out)
              /* Test values are small, so we omit length limit checks. */
              || !TEST_ptr(*out = OPENSSL_malloc(len + 1)))
          return 0;
      *outlen = len + 1;
  
      /*
       * foo => '3', 'f', 'o', 'o'
       * foo,bar => '3', 'f', 'o', 'o', '3', 'b', 'a', 'r'
       */
      memcpy(*out + 1, protos, len);
  
      prefix = 0;
      i = prefix + 1;
      while (i <= len) {
          if ((*out)[i] == ',') {
              if (!TEST_int_gt(i - 1, prefix))
                  goto err;
              (*out)[prefix] = (unsigned char)(i - 1 - prefix);
              prefix = i;
          }
          i++;
      }
      if (!TEST_int_gt(len, prefix))
          goto err;
      (*out)[prefix] = (unsigned char)(len - prefix);
      return 1;
  
  err:
      OPENSSL_free(*out);
      *out = NULL;
      return 0;
  }
  
  #ifndef OPENSSL_NO_NEXTPROTONEG
  /*
   * The client SHOULD select the first protocol advertised by the server that it
   * also supports.  In the event that the client doesn't support any of server's
   * protocols, or the server doesn't advertise any, it SHOULD select the first
   * protocol that it supports.
   */
  static int client_npn_cb(SSL *s, unsigned char **out, unsigned char *outlen,
                           const unsigned char *in, unsigned int inlen,
                           void *arg)
  {
      CTX_DATA *ctx_data = (CTX_DATA*)(arg);
      int ret;
  
      ret = SSL_select_next_proto(out, outlen, in, inlen,
                                  ctx_data->npn_protocols,
                                  ctx_data->npn_protocols_len);
      /* Accept both OPENSSL_NPN_NEGOTIATED and OPENSSL_NPN_NO_OVERLAP. */
      return TEST_true(ret == OPENSSL_NPN_NEGOTIATED || ret == OPENSSL_NPN_NO_OVERLAP)
          ? SSL_TLSEXT_ERR_OK : SSL_TLSEXT_ERR_ALERT_FATAL;
  }
  
  static int server_npn_cb(SSL *s, const unsigned char **data,
                           unsigned int *len, void *arg)
  {
      CTX_DATA *ctx_data = (CTX_DATA*)(arg);
      *data = ctx_data->npn_protocols;
      *len = ctx_data->npn_protocols_len;
      return SSL_TLSEXT_ERR_OK;
  }
  #endif
  
  /*
   * The server SHOULD select the most highly preferred protocol that it supports
   * and that is also advertised by the client.  In the event that the server
   * supports no protocols that the client advertises, then the server SHALL
   * respond with a fatal "no_application_protocol" alert.
   */
  static int server_alpn_cb(SSL *s, const unsigned char **out,
                            unsigned char *outlen, const unsigned char *in,
                            unsigned int inlen, void *arg)
  {
      CTX_DATA *ctx_data = (CTX_DATA*)(arg);
      int ret;
  
      /* SSL_select_next_proto isn't const-correct... */
      unsigned char *tmp_out;
  
      /*
       * The result points either to |in| or to |ctx_data->alpn_protocols|.
       * The callback is allowed to point to |in| or to a long-lived buffer,
       * so we can return directly without storing a copy.
       */
      ret = SSL_select_next_proto(&tmp_out, outlen,
                                  ctx_data->alpn_protocols,
                                  ctx_data->alpn_protocols_len, in, inlen);
  
      *out = tmp_out;
      /* Unlike NPN, we don't tolerate a mismatch. */
      return ret == OPENSSL_NPN_NEGOTIATED ? SSL_TLSEXT_ERR_OK
          : SSL_TLSEXT_ERR_ALERT_FATAL;
  }
  
  #ifndef OPENSSL_NO_SRP
  static char *client_srp_cb(SSL *s, void *arg)
  {
      CTX_DATA *ctx_data = (CTX_DATA*)(arg);
      return OPENSSL_strdup(ctx_data->srp_password);
  }
  
  static int server_srp_cb(SSL *s, int *ad, void *arg)
  {
      CTX_DATA *ctx_data = (CTX_DATA*)(arg);
      if (strcmp(ctx_data->srp_user, SSL_get_srp_username(s)) != 0)
          return SSL3_AL_FATAL;
      if (SSL_set_srp_server_param_pw(s, ctx_data->srp_user,
                                      ctx_data->srp_password,
                                      "2048" /* known group */) < 0) {
          *ad = SSL_AD_INTERNAL_ERROR;
          return SSL3_AL_FATAL;
      }
      return SSL_ERROR_NONE;
  }
  #endif  /* !OPENSSL_NO_SRP */
  
  static int generate_session_ticket_cb(SSL *s, void *arg)
  {
      CTX_DATA *server_ctx_data = arg;
      SSL_SESSION *ss = SSL_get_session(s);
      char *app_data = server_ctx_data->session_ticket_app_data;
  
      if (ss == NULL || app_data == NULL)
          return 0;
  
      return SSL_SESSION_set1_ticket_appdata(ss, app_data, strlen(app_data));
  }
  
  static int decrypt_session_ticket_cb(SSL *s, SSL_SESSION *ss,
                                       const unsigned char *keyname,
                                       size_t keyname_len,
                                       SSL_TICKET_STATUS status,
                                       void *arg)
  {
      switch (status) {
      case SSL_TICKET_EMPTY:
      case SSL_TICKET_NO_DECRYPT:
          return SSL_TICKET_RETURN_IGNORE_RENEW;
      case SSL_TICKET_SUCCESS:
          return SSL_TICKET_RETURN_USE;
      case SSL_TICKET_SUCCESS_RENEW:
          return SSL_TICKET_RETURN_USE_RENEW;
      default:
          break;
      }
      return SSL_TICKET_RETURN_ABORT;
  }
  
  /*
   * Configure callbacks and other properties that can't be set directly
   * in the server/client CONF.
   */
  static int configure_handshake_ctx(SSL_CTX *server_ctx, SSL_CTX *server2_ctx,
                                     SSL_CTX *client_ctx,
                                     const SSL_TEST_CTX *test,
                                     const SSL_TEST_EXTRA_CONF *extra,
                                     CTX_DATA *server_ctx_data,
                                     CTX_DATA *server2_ctx_data,
                                     CTX_DATA *client_ctx_data)
  {
      unsigned char *ticket_keys;
      size_t ticket_key_len;
  
      if (!TEST_int_eq(SSL_CTX_set_max_send_fragment(server_ctx,
                                                     test->max_fragment_size), 1))
          goto err;
      if (server2_ctx != NULL) {
          if (!TEST_int_eq(SSL_CTX_set_max_send_fragment(server2_ctx,
                                                         test->max_fragment_size),
                           1))
              goto err;
      }
      if (!TEST_int_eq(SSL_CTX_set_max_send_fragment(client_ctx,
                                                     test->max_fragment_size), 1))
          goto err;
  
      switch (extra->client.verify_callback) {
      case SSL_TEST_VERIFY_ACCEPT_ALL:
          SSL_CTX_set_cert_verify_callback(client_ctx, &verify_accept_cb, NULL);
          break;
      case SSL_TEST_VERIFY_REJECT_ALL:
          SSL_CTX_set_cert_verify_callback(client_ctx, &verify_reject_cb, NULL);
          break;
      case SSL_TEST_VERIFY_NONE:
          break;
      }
  
      switch (extra->client.max_fragment_len_mode) {
      case TLSEXT_max_fragment_length_512:
      case TLSEXT_max_fragment_length_1024:
      case TLSEXT_max_fragment_length_2048:
      case TLSEXT_max_fragment_length_4096:
      case TLSEXT_max_fragment_length_DISABLED:
          SSL_CTX_set_tlsext_max_fragment_length(
                client_ctx, extra->client.max_fragment_len_mode);
          break;
      }
  
      /*
       * Link the two contexts for SNI purposes.
       * Also do ClientHello callbacks here, as setting both ClientHello and SNI
       * is bad.
       */
      switch (extra->server.servername_callback) {
      case SSL_TEST_SERVERNAME_IGNORE_MISMATCH:
          SSL_CTX_set_tlsext_servername_callback(server_ctx, servername_ignore_cb);
          SSL_CTX_set_tlsext_servername_arg(server_ctx, server2_ctx);
          break;
      case SSL_TEST_SERVERNAME_REJECT_MISMATCH:
          SSL_CTX_set_tlsext_servername_callback(server_ctx, servername_reject_cb);
          SSL_CTX_set_tlsext_servername_arg(server_ctx, server2_ctx);
          break;
      case SSL_TEST_SERVERNAME_CB_NONE:
          break;
      case SSL_TEST_SERVERNAME_CLIENT_HELLO_IGNORE_MISMATCH:
          SSL_CTX_set_client_hello_cb(server_ctx, client_hello_ignore_cb, server2_ctx);
          break;
      case SSL_TEST_SERVERNAME_CLIENT_HELLO_REJECT_MISMATCH:
          SSL_CTX_set_client_hello_cb(server_ctx, client_hello_reject_cb, server2_ctx);
          break;
      case SSL_TEST_SERVERNAME_CLIENT_HELLO_NO_V12:
          SSL_CTX_set_client_hello_cb(server_ctx, client_hello_nov12_cb, server2_ctx);
      }
  
      if (extra->server.cert_status != SSL_TEST_CERT_STATUS_NONE) {
          SSL_CTX_set_tlsext_status_type(client_ctx, TLSEXT_STATUSTYPE_ocsp);
          SSL_CTX_set_tlsext_status_cb(client_ctx, client_ocsp_cb);
          SSL_CTX_set_tlsext_status_arg(client_ctx, NULL);
          SSL_CTX_set_tlsext_status_cb(server_ctx, server_ocsp_cb);
          SSL_CTX_set_tlsext_status_arg(server_ctx,
              ((extra->server.cert_status == SSL_TEST_CERT_STATUS_GOOD_RESPONSE)
              ? &dummy_ocsp_resp_good_val : &dummy_ocsp_resp_bad_val));
      }
  
      /*
       * The initial_ctx/session_ctx always handles the encrypt/decrypt of the
       * session ticket. This ticket_key callback is assigned to the second
       * session (assigned via SNI), and should never be invoked
       */
      if (server2_ctx != NULL)
          SSL_CTX_set_tlsext_ticket_key_cb(server2_ctx,
                                           do_not_call_session_ticket_cb);
  
      if (extra->server.broken_session_ticket) {
          SSL_CTX_set_tlsext_ticket_key_cb(server_ctx, broken_session_ticket_cb);
      }
  #ifndef OPENSSL_NO_NEXTPROTONEG
      if (extra->server.npn_protocols != NULL) {
          if (!TEST_true(parse_protos(extra->server.npn_protocols,
                                      &server_ctx_data->npn_protocols,
                                      &server_ctx_data->npn_protocols_len)))
              goto err;
          SSL_CTX_set_npn_advertised_cb(server_ctx, server_npn_cb,
                                        server_ctx_data);
      }
      if (extra->server2.npn_protocols != NULL) {
          if (!TEST_true(parse_protos(extra->server2.npn_protocols,
                                      &server2_ctx_data->npn_protocols,
                                      &server2_ctx_data->npn_protocols_len))
                  || !TEST_ptr(server2_ctx))
              goto err;
          SSL_CTX_set_npn_advertised_cb(server2_ctx, server_npn_cb,
                                        server2_ctx_data);
      }
      if (extra->client.npn_protocols != NULL) {
          if (!TEST_true(parse_protos(extra->client.npn_protocols,
                                      &client_ctx_data->npn_protocols,
                                      &client_ctx_data->npn_protocols_len)))
              goto err;
          SSL_CTX_set_next_proto_select_cb(client_ctx, client_npn_cb,
                                           client_ctx_data);
      }
  #endif
      if (extra->server.alpn_protocols != NULL) {
          if (!TEST_true(parse_protos(extra->server.alpn_protocols,
                                      &server_ctx_data->alpn_protocols,
                                      &server_ctx_data->alpn_protocols_len)))
              goto err;
          SSL_CTX_set_alpn_select_cb(server_ctx, server_alpn_cb, server_ctx_data);
      }
      if (extra->server2.alpn_protocols != NULL) {
          if (!TEST_ptr(server2_ctx)
                  || !TEST_true(parse_protos(extra->server2.alpn_protocols,
                                             &server2_ctx_data->alpn_protocols,
                                             &server2_ctx_data->alpn_protocols_len
              )))
              goto err;
          SSL_CTX_set_alpn_select_cb(server2_ctx, server_alpn_cb,
                                     server2_ctx_data);
      }
      if (extra->client.alpn_protocols != NULL) {
          unsigned char *alpn_protos = NULL;
          size_t alpn_protos_len;
          if (!TEST_true(parse_protos(extra->client.alpn_protocols,
                                      &alpn_protos, &alpn_protos_len))
                  /* Reversed return value convention... */
                  || !TEST_int_eq(SSL_CTX_set_alpn_protos(client_ctx, alpn_protos,
                                                          alpn_protos_len), 0))
              goto err;
          OPENSSL_free(alpn_protos);
      }
  
      if (extra->server.session_ticket_app_data != NULL) {
          server_ctx_data->session_ticket_app_data =
              OPENSSL_strdup(extra->server.session_ticket_app_data);
          SSL_CTX_set_session_ticket_cb(server_ctx, generate_session_ticket_cb,
                                        decrypt_session_ticket_cb, server_ctx_data);
      }
      if (extra->server2.session_ticket_app_data != NULL) {
          if (!TEST_ptr(server2_ctx))
              goto err;
          server2_ctx_data->session_ticket_app_data =
              OPENSSL_strdup(extra->server2.session_ticket_app_data);
          SSL_CTX_set_session_ticket_cb(server2_ctx, NULL,
                                        decrypt_session_ticket_cb, server2_ctx_data);
      }
  
      /*
       * Use fixed session ticket keys so that we can decrypt a ticket created with
       * one CTX in another CTX. Don't address server2 for the moment.
       */
      ticket_key_len = SSL_CTX_set_tlsext_ticket_keys(server_ctx, NULL, 0);
      if (!TEST_ptr(ticket_keys = OPENSSL_zalloc(ticket_key_len))
              || !TEST_int_eq(SSL_CTX_set_tlsext_ticket_keys(server_ctx,
                                                             ticket_keys,
                                                             ticket_key_len), 1)) {
          OPENSSL_free(ticket_keys);
          goto err;
      }
      OPENSSL_free(ticket_keys);
  
      /* The default log list includes EC keys, so CT can't work without EC. */
  #if !defined(OPENSSL_NO_CT) && !defined(OPENSSL_NO_EC)
      if (!TEST_true(SSL_CTX_set_default_ctlog_list_file(client_ctx)))
          goto err;
      switch (extra->client.ct_validation) {
      case SSL_TEST_CT_VALIDATION_PERMISSIVE:
          if (!TEST_true(SSL_CTX_enable_ct(client_ctx,
                                           SSL_CT_VALIDATION_PERMISSIVE)))
              goto err;
          break;
      case SSL_TEST_CT_VALIDATION_STRICT:
          if (!TEST_true(SSL_CTX_enable_ct(client_ctx, SSL_CT_VALIDATION_STRICT)))
              goto err;
          break;
      case SSL_TEST_CT_VALIDATION_NONE:
          break;
      }
  #endif
  #ifndef OPENSSL_NO_SRP
      if (extra->server.srp_user != NULL) {
          SSL_CTX_set_srp_username_callback(server_ctx, server_srp_cb);
          server_ctx_data->srp_user = OPENSSL_strdup(extra->server.srp_user);
          server_ctx_data->srp_password = OPENSSL_strdup(extra->server.srp_password);
          SSL_CTX_set_srp_cb_arg(server_ctx, server_ctx_data);
      }
      if (extra->server2.srp_user != NULL) {
          if (!TEST_ptr(server2_ctx))
              goto err;
          SSL_CTX_set_srp_username_callback(server2_ctx, server_srp_cb);
          server2_ctx_data->srp_user = OPENSSL_strdup(extra->server2.srp_user);
          server2_ctx_data->srp_password = OPENSSL_strdup(extra->server2.srp_password);
          SSL_CTX_set_srp_cb_arg(server2_ctx, server2_ctx_data);
      }
      if (extra->client.srp_user != NULL) {
          if (!TEST_true(SSL_CTX_set_srp_username(client_ctx,
                                                  extra->client.srp_user)))
              goto err;
          SSL_CTX_set_srp_client_pwd_callback(client_ctx, client_srp_cb);
          client_ctx_data->srp_password = OPENSSL_strdup(extra->client.srp_password);
          SSL_CTX_set_srp_cb_arg(client_ctx, client_ctx_data);
      }
  #endif  /* !OPENSSL_NO_SRP */
      return 1;
  err:
      return 0;
  }
  
  /* Configure per-SSL callbacks and other properties. */
  static void configure_handshake_ssl(SSL *server, SSL *client,
                                      const SSL_TEST_EXTRA_CONF *extra)
  {
      if (extra->client.servername != SSL_TEST_SERVERNAME_NONE)
          SSL_set_tlsext_host_name(client,
                                   ssl_servername_name(extra->client.servername));
      if (extra->client.enable_pha)
          SSL_set_post_handshake_auth(client, 1);
  }
  
  /* The status for each connection phase. */
  typedef enum {
      PEER_SUCCESS,
      PEER_RETRY,
      PEER_ERROR,
      PEER_WAITING,
      PEER_TEST_FAILURE
  } peer_status_t;
  
  /* An SSL object and associated read-write buffers. */
  typedef struct peer_st {
      SSL *ssl;
      /* Buffer lengths are int to match the SSL read/write API. */
      unsigned char *write_buf;
      int write_buf_len;
      unsigned char *read_buf;
      int read_buf_len;
      int bytes_to_write;
      int bytes_to_read;
      peer_status_t status;
  } PEER;
  
  static int create_peer(PEER *peer, SSL_CTX *ctx)
  {
      static const int peer_buffer_size = 64 * 1024;
      SSL *ssl = NULL;
      unsigned char *read_buf = NULL, *write_buf = NULL;
  
      if (!TEST_ptr(ssl = SSL_new(ctx))
              || !TEST_ptr(write_buf = OPENSSL_zalloc(peer_buffer_size))
              || !TEST_ptr(read_buf = OPENSSL_zalloc(peer_buffer_size)))
          goto err;
  
      peer->ssl = ssl;
      peer->write_buf = write_buf;
      peer->read_buf = read_buf;
      peer->write_buf_len = peer->read_buf_len = peer_buffer_size;
      return 1;
  err:
      SSL_free(ssl);
      OPENSSL_free(write_buf);
      OPENSSL_free(read_buf);
      return 0;
  }
  
  static void peer_free_data(PEER *peer)
  {
      SSL_free(peer->ssl);
      OPENSSL_free(peer->write_buf);
      OPENSSL_free(peer->read_buf);
  }
  
  /*
   * Note that we could do the handshake transparently under an SSL_write,
   * but separating the steps is more helpful for debugging test failures.
   */
  static void do_handshake_step(PEER *peer)
  {
      if (!TEST_int_eq(peer->status, PEER_RETRY)) {
          peer->status = PEER_TEST_FAILURE;
      } else {
          int ret = SSL_do_handshake(peer->ssl);
  
          if (ret == 1) {
              peer->status = PEER_SUCCESS;
          } else if (ret == 0) {
              peer->status = PEER_ERROR;
          } else {
              int error = SSL_get_error(peer->ssl, ret);
              /* Memory bios should never block with SSL_ERROR_WANT_WRITE. */
              if (error != SSL_ERROR_WANT_READ)
                  peer->status = PEER_ERROR;
          }
      }
  }
  
  /*-
   * Send/receive some application data. The read-write sequence is
   * Peer A: (R) W - first read will yield no data
   * Peer B:  R  W
   * ...
   * Peer A:  R  W
   * Peer B:  R  W
   * Peer A:  R
   */
  static void do_app_data_step(PEER *peer)
  {
      int ret = 1, write_bytes;
  
      if (!TEST_int_eq(peer->status, PEER_RETRY)) {
          peer->status = PEER_TEST_FAILURE;
          return;
      }
  
      /* We read everything available... */
      while (ret > 0 && peer->bytes_to_read) {
          ret = SSL_read(peer->ssl, peer->read_buf, peer->read_buf_len);
          if (ret > 0) {
              if (!TEST_int_le(ret, peer->bytes_to_read)) {
                  peer->status = PEER_TEST_FAILURE;
                  return;
              }
              peer->bytes_to_read -= ret;
          } else if (ret == 0) {
              peer->status = PEER_ERROR;
              return;
          } else {
              int error = SSL_get_error(peer->ssl, ret);
              if (error != SSL_ERROR_WANT_READ) {
                  peer->status = PEER_ERROR;
                  return;
              } /* Else continue with write. */
          }
      }
  
      /* ... but we only write one write-buffer-full of data. */
      write_bytes = peer->bytes_to_write < peer->write_buf_len ? peer->bytes_to_write :
          peer->write_buf_len;
      if (write_bytes) {
          ret = SSL_write(peer->ssl, peer->write_buf, write_bytes);
          if (ret > 0) {
              /* SSL_write will only succeed with a complete write. */
              if (!TEST_int_eq(ret, write_bytes)) {
                  peer->status = PEER_TEST_FAILURE;
                  return;
              }
              peer->bytes_to_write -= ret;
          } else {
              /*
               * We should perhaps check for SSL_ERROR_WANT_READ/WRITE here
               * but this doesn't yet occur with current app data sizes.
               */
              peer->status = PEER_ERROR;
              return;
          }
      }
  
      /*
       * We could simply finish when there was nothing to read, and we have
       * nothing left to write. But keeping track of the expected number of bytes
       * to read gives us somewhat better guarantees that all data sent is in fact
       * received.
       */
      if (!peer->bytes_to_write && !peer->bytes_to_read) {
          peer->status = PEER_SUCCESS;
      }
  }
  
  static void do_reneg_setup_step(const SSL_TEST_CTX *test_ctx, PEER *peer)
  {
      int ret;
      char buf;
  
      if (peer->status == PEER_SUCCESS) {
          /*
           * We are a client that succeeded this step previously, but the server
           * wanted to retry. Probably there is a no_renegotiation warning alert
           * waiting for us. Attempt to continue the handshake.
           */
          peer->status = PEER_RETRY;
          do_handshake_step(peer);
          return;
      }
  
      if (!TEST_int_eq(peer->status, PEER_RETRY)
              || !TEST_true(test_ctx->handshake_mode
                                == SSL_TEST_HANDSHAKE_RENEG_SERVER
                            || test_ctx->handshake_mode
                                == SSL_TEST_HANDSHAKE_RENEG_CLIENT
                            || test_ctx->handshake_mode
                                == SSL_TEST_HANDSHAKE_KEY_UPDATE_SERVER
                            || test_ctx->handshake_mode
                                == SSL_TEST_HANDSHAKE_KEY_UPDATE_CLIENT
                            || test_ctx->handshake_mode
                                == SSL_TEST_HANDSHAKE_POST_HANDSHAKE_AUTH)) {
          peer->status = PEER_TEST_FAILURE;
          return;
      }
  
      /* Reset the count of the amount of app data we need to read/write */
      peer->bytes_to_write = peer->bytes_to_read = test_ctx->app_data_size;
  
      /* Check if we are the peer that is going to initiate */
      if ((test_ctx->handshake_mode == SSL_TEST_HANDSHAKE_RENEG_SERVER
                  && SSL_is_server(peer->ssl))
              || (test_ctx->handshake_mode == SSL_TEST_HANDSHAKE_RENEG_CLIENT
                  && !SSL_is_server(peer->ssl))) {
          /*
           * If we already asked for a renegotiation then fall through to the
           * SSL_read() below.
           */
          if (!SSL_renegotiate_pending(peer->ssl)) {
              /*
               * If we are the client we will always attempt to resume the
               * session. The server may or may not resume dependent on the
               * setting of SSL_OP_NO_SESSION_RESUMPTION_ON_RENEGOTIATION
               */
              if (SSL_is_server(peer->ssl)) {
                  ret = SSL_renegotiate(peer->ssl);
              } else {
                  if (test_ctx->extra.client.reneg_ciphers != NULL) {
                      if (!SSL_set_cipher_list(peer->ssl,
                                  test_ctx->extra.client.reneg_ciphers)) {
                          peer->status = PEER_ERROR;
                          return;
                      }
                      ret = SSL_renegotiate(peer->ssl);
                  } else {
                      ret = SSL_renegotiate_abbreviated(peer->ssl);
                  }
              }
              if (!ret) {
                  peer->status = PEER_ERROR;
                  return;
              }
              do_handshake_step(peer);
              /*
               * If status is PEER_RETRY it means we're waiting on the peer to
               * continue the handshake. As far as setting up the renegotiation is
               * concerned that is a success. The next step will continue the
               * handshake to its conclusion.
               *
               * If status is PEER_SUCCESS then we are the server and we have
               * successfully sent the HelloRequest. We need to continue to wait
               * until the handshake arrives from the client.
               */
              if (peer->status == PEER_RETRY)
                  peer->status = PEER_SUCCESS;
              else if (peer->status == PEER_SUCCESS)
                  peer->status = PEER_RETRY;
              return;
          }
      } else if (test_ctx->handshake_mode == SSL_TEST_HANDSHAKE_KEY_UPDATE_SERVER
                 || test_ctx->handshake_mode
                    == SSL_TEST_HANDSHAKE_KEY_UPDATE_CLIENT) {
          if (SSL_is_server(peer->ssl)
                  != (test_ctx->handshake_mode
                      == SSL_TEST_HANDSHAKE_KEY_UPDATE_SERVER)) {
              peer->status = PEER_SUCCESS;
              return;
          }
  
          ret = SSL_key_update(peer->ssl, test_ctx->key_update_type);
          if (!ret) {
              peer->status = PEER_ERROR;
              return;
          }
          do_handshake_step(peer);
          /*
           * This is a one step handshake. We shouldn't get anything other than
           * PEER_SUCCESS
           */
          if (peer->status != PEER_SUCCESS)
              peer->status = PEER_ERROR;
          return;
      } else if (test_ctx->handshake_mode == SSL_TEST_HANDSHAKE_POST_HANDSHAKE_AUTH) {
          if (SSL_is_server(peer->ssl)) {
              /* Make the server believe it's received the extension */
              if (test_ctx->extra.server.force_pha)
                  peer->ssl->post_handshake_auth = SSL_PHA_EXT_RECEIVED;
              ret = SSL_verify_client_post_handshake(peer->ssl);
              if (!ret) {
                  peer->status = PEER_ERROR;
                  return;
              }
          }
          do_handshake_step(peer);
          /*
           * This is a one step handshake. We shouldn't get anything other than
           * PEER_SUCCESS
           */
          if (peer->status != PEER_SUCCESS)
              peer->status = PEER_ERROR;
          return;
      }
  
      /*
       * The SSL object is still expecting app data, even though it's going to
       * get a handshake message. We try to read, and it should fail - after which
       * we should be in a handshake
       */
      ret = SSL_read(peer->ssl, &buf, sizeof(buf));
      if (ret >= 0) {
          /*
           * We're not actually expecting data - we're expecting a reneg to
           * start
           */
          peer->status = PEER_ERROR;
          return;
      } else {
          int error = SSL_get_error(peer->ssl, ret);
          if (error != SSL_ERROR_WANT_READ) {
              peer->status = PEER_ERROR;
              return;
          }
          /* If we're not in init yet then we're not done with setup yet */
          if (!SSL_in_init(peer->ssl))
              return;
      }
  
      peer->status = PEER_SUCCESS;
  }
  
  
  /*
   * RFC 5246 says:
   *
   * Note that as of TLS 1.1,
   *     failure to properly close a connection no longer requires that a
   *     session not be resumed.  This is a change from TLS 1.0 to conform
   *     with widespread implementation practice.
   *
   * However,
   * (a) OpenSSL requires that a connection be shutdown for all protocol versions.
   * (b) We test lower versions, too.
   * So we just implement shutdown. We do a full bidirectional shutdown so that we
   * can compare sent and received close_notify alerts and get some test coverage
   * for SSL_shutdown as a bonus.
   */
  static void do_shutdown_step(PEER *peer)
  {
      int ret;
  
      if (!TEST_int_eq(peer->status, PEER_RETRY)) {
          peer->status = PEER_TEST_FAILURE;
          return;
      }
      ret = SSL_shutdown(peer->ssl);
  
      if (ret == 1) {
          peer->status = PEER_SUCCESS;
      } else if (ret < 0) { /* On 0, we retry. */
          int error = SSL_get_error(peer->ssl, ret);
  
          if (error != SSL_ERROR_WANT_READ && error != SSL_ERROR_WANT_WRITE)
              peer->status = PEER_ERROR;
      }
  }
  
  typedef enum {
      HANDSHAKE,
      RENEG_APPLICATION_DATA,
      RENEG_SETUP,
      RENEG_HANDSHAKE,
      APPLICATION_DATA,
      SHUTDOWN,
      CONNECTION_DONE
  } connect_phase_t;
  
  
  static int renegotiate_op(const SSL_TEST_CTX *test_ctx)
  {
      switch (test_ctx->handshake_mode) {
      case SSL_TEST_HANDSHAKE_RENEG_SERVER:
      case SSL_TEST_HANDSHAKE_RENEG_CLIENT:
          return 1;
      default:
          return 0;
      }
  }
  static int post_handshake_op(const SSL_TEST_CTX *test_ctx)
  {
      switch (test_ctx->handshake_mode) {
      case SSL_TEST_HANDSHAKE_KEY_UPDATE_CLIENT:
      case SSL_TEST_HANDSHAKE_KEY_UPDATE_SERVER:
      case SSL_TEST_HANDSHAKE_POST_HANDSHAKE_AUTH:
          return 1;
      default:
          return 0;
      }
  }
  
  static connect_phase_t next_phase(const SSL_TEST_CTX *test_ctx,
                                    connect_phase_t phase)
  {
      switch (phase) {
      case HANDSHAKE:
          if (renegotiate_op(test_ctx) || post_handshake_op(test_ctx))
              return RENEG_APPLICATION_DATA;
          return APPLICATION_DATA;
      case RENEG_APPLICATION_DATA:
          return RENEG_SETUP;
      case RENEG_SETUP:
          if (post_handshake_op(test_ctx))
              return APPLICATION_DATA;
          return RENEG_HANDSHAKE;
      case RENEG_HANDSHAKE:
          return APPLICATION_DATA;
      case APPLICATION_DATA:
          return SHUTDOWN;
      case SHUTDOWN:
          return CONNECTION_DONE;
      case CONNECTION_DONE:
          TEST_error("Trying to progress after connection done");
          break;
      }
      return -1;
  }
  
  static void do_connect_step(const SSL_TEST_CTX *test_ctx, PEER *peer,
                              connect_phase_t phase)
  {
      switch (phase) {
      case HANDSHAKE:
          do_handshake_step(peer);
          break;
      case RENEG_APPLICATION_DATA:
          do_app_data_step(peer);
          break;
      case RENEG_SETUP:
          do_reneg_setup_step(test_ctx, peer);
          break;
      case RENEG_HANDSHAKE:
          do_handshake_step(peer);
          break;
      case APPLICATION_DATA:
          do_app_data_step(peer);
          break;
      case SHUTDOWN:
          do_shutdown_step(peer);
          break;
      case CONNECTION_DONE:
          TEST_error("Action after connection done");
          break;
      }
  }
  
  typedef enum {
      /* Both parties succeeded. */
      HANDSHAKE_SUCCESS,
      /* Client errored. */
      CLIENT_ERROR,
      /* Server errored. */
      SERVER_ERROR,
      /* Peers are in inconsistent state. */
      INTERNAL_ERROR,
      /* One or both peers not done. */
      HANDSHAKE_RETRY
  } handshake_status_t;
  
  /*
   * Determine the handshake outcome.
   * last_status: the status of the peer to have acted last.
   * previous_status: the status of the peer that didn't act last.
   * client_spoke_last: 1 if the client went last.
   */
  static handshake_status_t handshake_status(peer_status_t last_status,
                                             peer_status_t previous_status,
                                             int client_spoke_last)
  {
      switch (last_status) {
      case PEER_TEST_FAILURE:
          return INTERNAL_ERROR;
  
      case PEER_WAITING:
          /* Shouldn't ever happen */
          return INTERNAL_ERROR;
  
      case PEER_SUCCESS:
          switch (previous_status) {
          case PEER_TEST_FAILURE:
              return INTERNAL_ERROR;
          case PEER_SUCCESS:
              /* Both succeeded. */
              return HANDSHAKE_SUCCESS;
          case PEER_WAITING:
          case PEER_RETRY:
              /* Let the first peer finish. */
              return HANDSHAKE_RETRY;
          case PEER_ERROR:
              /*
               * Second peer succeeded despite the fact that the first peer
               * already errored. This shouldn't happen.
               */
              return INTERNAL_ERROR;
          }
          break;
  
      case PEER_RETRY:
          return HANDSHAKE_RETRY;
  
      case PEER_ERROR:
          switch (previous_status) {
          case PEER_TEST_FAILURE:
              return INTERNAL_ERROR;
          case PEER_WAITING:
              /* The client failed immediately before sending the ClientHello */
              return client_spoke_last ? CLIENT_ERROR : INTERNAL_ERROR;
          case PEER_SUCCESS:
              /*
               * First peer succeeded but second peer errored.
               * TODO(emilia): we should be able to continue here (with some
               * application data?) to ensure the first peer receives the
               * alert / close_notify.
               * (No tests currently exercise this branch.)
               */
              return client_spoke_last ? CLIENT_ERROR : SERVER_ERROR;
          case PEER_RETRY:
              /* We errored; let the peer finish. */
              return HANDSHAKE_RETRY;
          case PEER_ERROR:
              /* Both peers errored. Return the one that errored first. */
              return client_spoke_last ? SERVER_ERROR : CLIENT_ERROR;
          }
      }
      /* Control should never reach here. */
      return INTERNAL_ERROR;
  }
  
  /* Convert unsigned char buf's that shouldn't contain any NUL-bytes to char. */
  static char *dup_str(const unsigned char *in, size_t len)
  {
      char *ret = NULL;
  
      if (len == 0)
          return NULL;
  
      /* Assert that the string does not contain NUL-bytes. */
      if (TEST_size_t_eq(OPENSSL_strnlen((const char*)(in), len), len))
          TEST_ptr(ret = OPENSSL_strndup((const char*)(in), len));
      return ret;
  }
  
  static int pkey_type(EVP_PKEY *pkey)
  {
      int nid = EVP_PKEY_id(pkey);
  
  #ifndef OPENSSL_NO_EC
      if (nid == EVP_PKEY_EC) {
          const EC_KEY *ec = EVP_PKEY_get0_EC_KEY(pkey);
          return EC_GROUP_get_curve_name(EC_KEY_get0_group(ec));
      }
  #endif
      return nid;
  }
  
  static int peer_pkey_type(SSL *s)
  {
      X509 *x = SSL_get_peer_certificate(s);
  
      if (x != NULL) {
          int nid = pkey_type(X509_get0_pubkey(x));
  
          X509_free(x);
          return nid;
      }
      return NID_undef;
  }
  
  #if !defined(OPENSSL_NO_SCTP) && !defined(OPENSSL_NO_SOCK)
  static int set_sock_as_sctp(int sock)
  {
      struct sctp_assocparams assocparams;
      struct sctp_rtoinfo rto_info;
      BIO *tmpbio;
  
      /*
       * To allow tests to fail fast (within a second or so), reduce the
       * retransmission timeouts and the number of retransmissions.
       */
      memset(&rto_info, 0, sizeof(struct sctp_rtoinfo));
      rto_info.srto_initial = 100;
      rto_info.srto_max = 200;
      rto_info.srto_min = 50;
      (void)setsockopt(sock, IPPROTO_SCTP, SCTP_RTOINFO,
                       (const void *)&rto_info, sizeof(struct sctp_rtoinfo));
      memset(&assocparams, 0, sizeof(struct sctp_assocparams));
      assocparams.sasoc_asocmaxrxt = 2;
      (void)setsockopt(sock, IPPROTO_SCTP, SCTP_ASSOCINFO,
                       (const void *)&assocparams,
                       sizeof(struct sctp_assocparams));
  
      /*
       * For SCTP we have to set various options on the socket prior to
       * connecting. This is done automatically by BIO_new_dgram_sctp().
       * We don't actually need the created BIO though so we free it again
       * immediately.
       */
      tmpbio = BIO_new_dgram_sctp(sock, BIO_NOCLOSE);
  
      if (tmpbio == NULL)
          return 0;
      BIO_free(tmpbio);
  
      return 1;
  }
  
  static int create_sctp_socks(int *ssock, int *csock)
  {
      BIO_ADDRINFO *res = NULL;
      const BIO_ADDRINFO *ai = NULL;
      int lsock = INVALID_SOCKET, asock = INVALID_SOCKET;
      int consock = INVALID_SOCKET;
      int ret = 0;
      int family = 0;
  
      if (BIO_sock_init() != 1)
          return 0;
  
      /*
       * Port is 4463. It could be anything. It will fail if it's already being
       * used for some other SCTP service. It seems unlikely though so we don't
       * worry about it here.
       */
      if (!BIO_lookup_ex(NULL, "4463", BIO_LOOKUP_SERVER, family, SOCK_STREAM,
                         IPPROTO_SCTP, &res))
          return 0;
  
      for (ai = res; ai != NULL; ai = BIO_ADDRINFO_next(ai)) {
          family = BIO_ADDRINFO_family(ai);
          lsock = BIO_socket(family, SOCK_STREAM, IPPROTO_SCTP, 0);
          if (lsock == INVALID_SOCKET) {
              /* Maybe the kernel doesn't support the socket family, even if
               * BIO_lookup() added it in the returned result...
               */
              continue;
          }
  
          if (!set_sock_as_sctp(lsock)
                  || !BIO_listen(lsock, BIO_ADDRINFO_address(ai),
                                 BIO_SOCK_REUSEADDR)) {
              BIO_closesocket(lsock);
              lsock = INVALID_SOCKET;
              continue;
          }
  
          /* Success, don't try any more addresses */
          break;
      }
  
      if (lsock == INVALID_SOCKET)
          goto err;
  
      BIO_ADDRINFO_free(res);
      res = NULL;
  
      if (!BIO_lookup_ex(NULL, "4463", BIO_LOOKUP_CLIENT, family, SOCK_STREAM,
                          IPPROTO_SCTP, &res))
          goto err;
  
      consock = BIO_socket(family, SOCK_STREAM, IPPROTO_SCTP, 0);
      if (consock == INVALID_SOCKET)
          goto err;
  
      if (!set_sock_as_sctp(consock)
              || !BIO_connect(consock, BIO_ADDRINFO_address(res), 0)
              || !BIO_socket_nbio(consock, 1))
          goto err;
  
      asock = BIO_accept_ex(lsock, NULL, BIO_SOCK_NONBLOCK);
      if (asock == INVALID_SOCKET)
          goto err;
  
      *csock = consock;
      *ssock = asock;
      consock = asock = INVALID_SOCKET;
      ret = 1;
  
   err:
      BIO_ADDRINFO_free(res);
      if (consock != INVALID_SOCKET)
          BIO_closesocket(consock);
      if (lsock != INVALID_SOCKET)
          BIO_closesocket(lsock);
      if (asock != INVALID_SOCKET)
          BIO_closesocket(asock);
      return ret;
  }
  #endif
  
  /*
   * Note that |extra| points to the correct client/server configuration
   * within |test_ctx|. When configuring the handshake, general mode settings
   * are taken from |test_ctx|, and client/server-specific settings should be
   * taken from |extra|.
   *
   * The configuration code should never reach into |test_ctx->extra| or
   * |test_ctx->resume_extra| directly.
   *
   * (We could refactor test mode settings into a substructure. This would result
   * in cleaner argument passing but would complicate the test configuration
   * parsing.)
   */
  static HANDSHAKE_RESULT *do_handshake_internal(
      SSL_CTX *server_ctx, SSL_CTX *server2_ctx, SSL_CTX *client_ctx,
      const SSL_TEST_CTX *test_ctx, const SSL_TEST_EXTRA_CONF *extra,
      SSL_SESSION *session_in, SSL_SESSION *serv_sess_in,
      SSL_SESSION **session_out, SSL_SESSION **serv_sess_out)
  {
      PEER server, client;
      BIO *client_to_server = NULL, *server_to_client = NULL;
      HANDSHAKE_EX_DATA server_ex_data, client_ex_data;
      CTX_DATA client_ctx_data, server_ctx_data, server2_ctx_data;
      HANDSHAKE_RESULT *ret = HANDSHAKE_RESULT_new();
      int client_turn = 1, client_turn_count = 0, client_wait_count = 0;
      connect_phase_t phase = HANDSHAKE;
      handshake_status_t status = HANDSHAKE_RETRY;
      const unsigned char* tick = NULL;
      size_t tick_len = 0;
      const unsigned char* sess_id = NULL;
      unsigned int sess_id_len = 0;
      SSL_SESSION* sess = NULL;
      const unsigned char *proto = NULL;
      /* API dictates unsigned int rather than size_t. */
      unsigned int proto_len = 0;
      EVP_PKEY *tmp_key;
      const STACK_OF(X509_NAME) *names;
      time_t start;
      const char* cipher;
  
      if (ret == NULL)
          return NULL;
  
      memset(&server_ctx_data, 0, sizeof(server_ctx_data));
      memset(&server2_ctx_data, 0, sizeof(server2_ctx_data));
      memset(&client_ctx_data, 0, sizeof(client_ctx_data));
      memset(&server, 0, sizeof(server));
      memset(&client, 0, sizeof(client));
      memset(&server_ex_data, 0, sizeof(server_ex_data));
      memset(&client_ex_data, 0, sizeof(client_ex_data));
  
      if (!configure_handshake_ctx(server_ctx, server2_ctx, client_ctx,
                                   test_ctx, extra, &server_ctx_data,
                                   &server2_ctx_data, &client_ctx_data)) {
          TEST_note("configure_handshake_ctx");
          return NULL;
      }
  
  #if !defined(OPENSSL_NO_SCTP) && !defined(OPENSSL_NO_SOCK)
      if (test_ctx->enable_client_sctp_label_bug)
          SSL_CTX_set_mode(client_ctx, SSL_MODE_DTLS_SCTP_LABEL_LENGTH_BUG);
      if (test_ctx->enable_server_sctp_label_bug)
          SSL_CTX_set_mode(server_ctx, SSL_MODE_DTLS_SCTP_LABEL_LENGTH_BUG);
  #endif
  
      /* Setup SSL and buffers; additional configuration happens below. */
      if (!create_peer(&server, server_ctx)) {
          TEST_note("creating server context");
          goto err;
      }
      if (!create_peer(&client, client_ctx)) {
          TEST_note("creating client context");
          goto err;
      }
  
      server.bytes_to_write = client.bytes_to_read = test_ctx->app_data_size;
      client.bytes_to_write = server.bytes_to_read = test_ctx->app_data_size;
  
      configure_handshake_ssl(server.ssl, client.ssl, extra);
      if (session_in != NULL) {
          SSL_SESSION_get_id(serv_sess_in, &sess_id_len);
          /* In case we're testing resumption without tickets. */
          if ((sess_id_len > 0
                      && !TEST_true(SSL_CTX_add_session(server_ctx,
                                                        serv_sess_in)))
                  || !TEST_true(SSL_set_session(client.ssl, session_in)))
              goto err;
          sess_id_len = 0;
      }
  
      ret->result = SSL_TEST_INTERNAL_ERROR;
  
      if (test_ctx->use_sctp) {
  #if !defined(OPENSSL_NO_SCTP) && !defined(OPENSSL_NO_SOCK)
          int csock, ssock;
  
          if (create_sctp_socks(&ssock, &csock)) {
              client_to_server = BIO_new_dgram_sctp(csock, BIO_CLOSE);
              server_to_client = BIO_new_dgram_sctp(ssock, BIO_CLOSE);
          }
  #endif
      } else {
          client_to_server = BIO_new(BIO_s_mem());
          server_to_client = BIO_new(BIO_s_mem());
      }
  
      if (!TEST_ptr(client_to_server)
              || !TEST_ptr(server_to_client))
          goto err;
  
      /* Non-blocking bio. */
      BIO_set_nbio(client_to_server, 1);
      BIO_set_nbio(server_to_client, 1);
  
      SSL_set_connect_state(client.ssl);
      SSL_set_accept_state(server.ssl);
  
      /* The bios are now owned by the SSL object. */
      if (test_ctx->use_sctp) {
          SSL_set_bio(client.ssl, client_to_server, client_to_server);
          SSL_set_bio(server.ssl, server_to_client, server_to_client);
      } else {
          SSL_set_bio(client.ssl, server_to_client, client_to_server);
          if (!TEST_int_gt(BIO_up_ref(server_to_client), 0)
                  || !TEST_int_gt(BIO_up_ref(client_to_server), 0))
              goto err;
          SSL_set_bio(server.ssl, client_to_server, server_to_client);
      }
  
      ex_data_idx = SSL_get_ex_new_index(0, "ex data", NULL, NULL, NULL);
      if (!TEST_int_ge(ex_data_idx, 0)
              || !TEST_int_eq(SSL_set_ex_data(server.ssl, ex_data_idx, &server_ex_data), 1)
              || !TEST_int_eq(SSL_set_ex_data(client.ssl, ex_data_idx, &client_ex_data), 1))
          goto err;
  
      SSL_set_info_callback(server.ssl, &info_cb);
      SSL_set_info_callback(client.ssl, &info_cb);
  
      client.status = PEER_RETRY;
      server.status = PEER_WAITING;
  
      start = time(NULL);
  
      /*
       * Half-duplex handshake loop.
       * Client and server speak to each other synchronously in the same process.
       * We use non-blocking BIOs, so whenever one peer blocks for read, it
       * returns PEER_RETRY to indicate that it's the other peer's turn to write.
       * The handshake succeeds once both peers have succeeded. If one peer
       * errors out, we also let the other peer retry (and presumably fail).
       */
      for(;;) {
          if (client_turn) {
              do_connect_step(test_ctx, &client, phase);
              status = handshake_status(client.status, server.status,
                                        1 /* client went last */);
              if (server.status == PEER_WAITING)
                  server.status = PEER_RETRY;
          } else {
              do_connect_step(test_ctx, &server, phase);
              status = handshake_status(server.status, client.status,
                                        0 /* server went last */);
          }
  
          switch (status) {
          case HANDSHAKE_SUCCESS:
              client_turn_count = 0;
              phase = next_phase(test_ctx, phase);
              if (phase == CONNECTION_DONE) {
                  ret->result = SSL_TEST_SUCCESS;
                  goto err;
              } else {
                  client.status = server.status = PEER_RETRY;
                  /*
                   * For now, client starts each phase. Since each phase is
                   * started separately, we can later control this more
                   * precisely, for example, to test client-initiated and
                   * server-initiated shutdown.
                   */
                  client_turn = 1;
                  break;
              }
          case CLIENT_ERROR:
              ret->result = SSL_TEST_CLIENT_FAIL;
              goto err;
          case SERVER_ERROR:
              ret->result = SSL_TEST_SERVER_FAIL;
              goto err;
          case INTERNAL_ERROR:
              ret->result = SSL_TEST_INTERNAL_ERROR;
              goto err;
          case HANDSHAKE_RETRY:
              if (test_ctx->use_sctp) {
                  if (time(NULL) - start > 3) {
                      /*
                       * We've waited for too long. Give up.
                       */
                      ret->result = SSL_TEST_INTERNAL_ERROR;
                      goto err;
                  }
                  /*
                   * With "real" sockets we only swap to processing the peer
                   * if they are expecting to retry. Otherwise we just retry the
                   * same endpoint again.
                   */
                  if ((client_turn && server.status == PEER_RETRY)
                          || (!client_turn && client.status == PEER_RETRY))
                      client_turn ^= 1;
              } else {
                  if (client_turn_count++ >= 2000) {
                      /*
                       * At this point, there's been so many PEER_RETRY in a row
                       * that it's likely both sides are stuck waiting for a read.
                       * It's time to give up.
                       */
                      ret->result = SSL_TEST_INTERNAL_ERROR;
                      goto err;
                  }
                  if (client_turn && server.status == PEER_SUCCESS) {
                      /*
                       * The server may finish before the client because the
                       * client spends some turns processing NewSessionTickets.
                       */
                      if (client_wait_count++ >= 2) {
                          ret->result = SSL_TEST_INTERNAL_ERROR;
                          goto err;
                      }
                  } else {
                      /* Continue. */
                      client_turn ^= 1;
                  }
              }
              break;
          }
      }
   err:
      ret->server_alert_sent = server_ex_data.alert_sent;
      ret->server_num_fatal_alerts_sent = server_ex_data.num_fatal_alerts_sent;
      ret->server_alert_received = client_ex_data.alert_received;
      ret->client_alert_sent = client_ex_data.alert_sent;
      ret->client_num_fatal_alerts_sent = client_ex_data.num_fatal_alerts_sent;
      ret->client_alert_received = server_ex_data.alert_received;
      ret->server_protocol = SSL_version(server.ssl);
      ret->client_protocol = SSL_version(client.ssl);
      ret->servername = server_ex_data.servername;
      if ((sess = SSL_get0_session(client.ssl)) != NULL) {
          SSL_SESSION_get0_ticket(sess, &tick, &tick_len);
          sess_id = SSL_SESSION_get_id(sess, &sess_id_len);
      }
      if (tick == NULL || tick_len == 0)
          ret->session_ticket = SSL_TEST_SESSION_TICKET_NO;
      else
          ret->session_ticket = SSL_TEST_SESSION_TICKET_YES;
      ret->compression = (SSL_get_current_compression(client.ssl) == NULL)
                         ? SSL_TEST_COMPRESSION_NO
                         : SSL_TEST_COMPRESSION_YES;
      if (sess_id == NULL || sess_id_len == 0)
          ret->session_id = SSL_TEST_SESSION_ID_NO;
      else
          ret->session_id = SSL_TEST_SESSION_ID_YES;
      ret->session_ticket_do_not_call = server_ex_data.session_ticket_do_not_call;
  
  #ifndef OPENSSL_NO_NEXTPROTONEG
      SSL_get0_next_proto_negotiated(client.ssl, &proto, &proto_len);
      ret->client_npn_negotiated = dup_str(proto, proto_len);
  
      SSL_get0_next_proto_negotiated(server.ssl, &proto, &proto_len);
      ret->server_npn_negotiated = dup_str(proto, proto_len);
  #endif
  
      SSL_get0_alpn_selected(client.ssl, &proto, &proto_len);
      ret->client_alpn_negotiated = dup_str(proto, proto_len);
  
      SSL_get0_alpn_selected(server.ssl, &proto, &proto_len);
      ret->server_alpn_negotiated = dup_str(proto, proto_len);
  
      if ((sess = SSL_get0_session(server.ssl)) != NULL) {
          SSL_SESSION_get0_ticket_appdata(sess, (void**)&tick, &tick_len);
          ret->result_session_ticket_app_data = OPENSSL_strndup((const char*)tick, tick_len);
      }
  
      ret->client_resumed = SSL_session_reused(client.ssl);
      ret->server_resumed = SSL_session_reused(server.ssl);
  
      cipher = SSL_CIPHER_get_name(SSL_get_current_cipher(client.ssl));
      ret->cipher = dup_str((const unsigned char*)cipher, strlen(cipher));
  
      if (session_out != NULL)
          *session_out = SSL_get1_session(client.ssl);
      if (serv_sess_out != NULL) {
          SSL_SESSION *tmp = SSL_get_session(server.ssl);
  
          /*
           * We create a fresh copy that is not in the server session ctx linked
           * list.
           */
          if (tmp != NULL)
              *serv_sess_out = SSL_SESSION_dup(tmp);
      }
  
      if (SSL_get_peer_tmp_key(client.ssl, &tmp_key)) {
          ret->tmp_key_type = pkey_type(tmp_key);
          EVP_PKEY_free(tmp_key);
      }
  
      SSL_get_peer_signature_nid(client.ssl, &ret->server_sign_hash);
      SSL_get_peer_signature_nid(server.ssl, &ret->client_sign_hash);
  
      SSL_get_peer_signature_type_nid(client.ssl, &ret->server_sign_type);
      SSL_get_peer_signature_type_nid(server.ssl, &ret->client_sign_type);
  
      names = SSL_get0_peer_CA_list(client.ssl);
      if (names == NULL)
          ret->client_ca_names = NULL;
      else
          ret->client_ca_names = SSL_dup_CA_list(names);
  
      names = SSL_get0_peer_CA_list(server.ssl);
      if (names == NULL)
          ret->server_ca_names = NULL;
      else
          ret->server_ca_names = SSL_dup_CA_list(names);
  
      ret->server_cert_type = peer_pkey_type(client.ssl);
      ret->client_cert_type = peer_pkey_type(server.ssl);
  
      ctx_data_free_data(&server_ctx_data);
      ctx_data_free_data(&server2_ctx_data);
      ctx_data_free_data(&client_ctx_data);
  
      peer_free_data(&server);
      peer_free_data(&client);
      return ret;
  }
  
  HANDSHAKE_RESULT *do_handshake(SSL_CTX *server_ctx, SSL_CTX *server2_ctx,
                                 SSL_CTX *client_ctx, SSL_CTX *resume_server_ctx,
                                 SSL_CTX *resume_client_ctx,
                                 const SSL_TEST_CTX *test_ctx)
  {
      HANDSHAKE_RESULT *result;
      SSL_SESSION *session = NULL, *serv_sess = NULL;
  
      result = do_handshake_internal(server_ctx, server2_ctx, client_ctx,
                                     test_ctx, &test_ctx->extra,
                                     NULL, NULL, &session, &serv_sess);
      if (result == NULL
              || test_ctx->handshake_mode != SSL_TEST_HANDSHAKE_RESUME
              || result->result == SSL_TEST_INTERNAL_ERROR)
          goto end;
  
      if (result->result != SSL_TEST_SUCCESS) {
          result->result = SSL_TEST_FIRST_HANDSHAKE_FAILED;
          goto end;
      }
  
      HANDSHAKE_RESULT_free(result);
      /* We don't support SNI on second handshake yet, so server2_ctx is NULL. */
      result = do_handshake_internal(resume_server_ctx, NULL, resume_client_ctx,
                                     test_ctx, &test_ctx->resume_extra,
                                     session, serv_sess, NULL, NULL);
   end:
      SSL_SESSION_free(session);
      SSL_SESSION_free(serv_sess);
      return result;
  }
  