diff --git a/src/ssl/handshake_server.cc b/src/ssl/handshake_server.cc
index 2d5b85e..f196db0 100644
--- a/src/ssl/handshake_server.cc
+++ b/src/ssl/handshake_server.cc
@@ -4,21 +4,21 @@
  * This package is an SSL implementation written
  * by Eric Young (eay@cryptsoft.com).
  * The implementation was written so as to conform with Netscapes SSL.
- * 
+ *
  * This library is free for commercial and non-commercial use as long as
  * the following conditions are aheared to.  The following conditions
  * apply to all code found in this distribution, be it the RC4, RSA,
  * lhash, DES, etc., code; not just the SSL code.  The SSL documentation
  * included with this distribution is covered by the same copyright terms
  * except that the holder is Tim Hudson (tjh@cryptsoft.com).
- * 
+ *
  * Copyright remains Eric Young's, and as such any Copyright notices in
  * the code are not to be removed.
  * If this package is used in a product, Eric Young should be given attribution
  * as the author of the parts of the library used.
  * This can be in the form of a textual message at program startup or
  * in documentation (online or textual) provided with the package.
- * 
+ *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
@@ -33,10 +33,10 @@
  *     Eric Young (eay@cryptsoft.com)"
  *    The word 'cryptographic' can be left out if the rouines from the library
  *    being used are not cryptographic related :-).
- * 4. If you include any Windows specific code (or a derivative thereof) from 
+ * 4. If you include any Windows specific code (or a derivative thereof) from
  *    the apps directory (application code) you must include an acknowledgement:
  *    "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
- * 
+ *
  * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
@@ -48,7 +48,7 @@
  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  * SUCH DAMAGE.
- * 
+ *
  * The licence and distribution terms for any publically available version or
  * derivative of this code cannot be changed.  i.e. this code cannot simply be
  * copied and put under another distribution licence
@@ -62,7 +62,7 @@
  * are met:
  *
  * 1. Redistributions of source code must retain the above copyright
- *    notice, this list of conditions and the following disclaimer. 
+ *    notice, this list of conditions and the following disclaimer.
  *
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in
@@ -110,7 +110,7 @@
 /* ====================================================================
  * Copyright 2002 Sun Microsystems, Inc. ALL RIGHTS RESERVED.
  *
- * Portions of the attached software ("Contribution") are developed by 
+ * Portions of the attached software ("Contribution") are developed by
  * SUN MICROSYSTEMS, INC., and are contributed to the OpenSSL project.
  *
  * The Contribution is licensed pursuant to the OpenSSL open source
@@ -172,284 +172,29 @@
 
 namespace bssl {
 
-static int ssl3_read_client_hello(SSL_HANDSHAKE *hs);
-static int ssl3_select_certificate(SSL_HANDSHAKE *hs);
-static int ssl3_select_parameters(SSL_HANDSHAKE *hs);
-static int ssl3_send_server_hello(SSL_HANDSHAKE *hs);
-static int ssl3_send_server_certificate(SSL_HANDSHAKE *hs);
-static int ssl3_send_server_key_exchange(SSL_HANDSHAKE *hs);
-static int ssl3_send_server_hello_done(SSL_HANDSHAKE *hs);
-static int ssl3_get_client_certificate(SSL_HANDSHAKE *hs);
-static int ssl3_get_client_key_exchange(SSL_HANDSHAKE *hs);
-static int ssl3_get_cert_verify(SSL_HANDSHAKE *hs);
-static int ssl3_get_next_proto(SSL_HANDSHAKE *hs);
-static int ssl3_get_channel_id(SSL_HANDSHAKE *hs);
-static int ssl3_send_server_finished(SSL_HANDSHAKE *hs);
-
-int ssl3_accept(SSL_HANDSHAKE *hs) {
-  SSL *const ssl = hs->ssl;
-  int ret = -1;
-
-  assert(ssl->handshake_func == ssl3_accept);
-  assert(ssl->server);
-
-  for (;;) {
-    int state = hs->state;
-
-    switch (hs->state) {
-      case SSL_ST_INIT:
-        ssl_do_info_callback(ssl, SSL_CB_HANDSHAKE_START, 1);
-        hs->state = SSL3_ST_SR_CLNT_HELLO_A;
-        break;
-
-      case SSL3_ST_SR_CLNT_HELLO_A:
-        ret = ssl3_read_client_hello(hs);
-        if (ret <= 0) {
-          goto end;
-        }
-        hs->state = SSL3_ST_SR_CLNT_HELLO_B;
-        break;
-
-      case SSL3_ST_SR_CLNT_HELLO_B:
-        ret = ssl3_select_certificate(hs);
-        if (ret <= 0) {
-          goto end;
-        }
-        if (hs->state != SSL_ST_TLS13) {
-          hs->state = SSL3_ST_SR_CLNT_HELLO_C;
-        }
-        break;
-
-      case SSL3_ST_SR_CLNT_HELLO_C:
-        ret = ssl3_select_parameters(hs);
-        if (ret <= 0) {
-          goto end;
-        }
-        hs->state = SSL3_ST_SW_SRVR_HELLO_A;
-        break;
-
-      case SSL3_ST_SW_SRVR_HELLO_A:
-        ret = ssl3_send_server_hello(hs);
-        if (ret <= 0) {
-          goto end;
-        }
-        if (ssl->session != NULL) {
-          hs->state = SSL3_ST_SW_FINISHED_A;
-        } else {
-          hs->state = SSL3_ST_SW_CERT_A;
-        }
-        break;
-
-      case SSL3_ST_SW_CERT_A:
-        ret = ssl3_send_server_certificate(hs);
-        if (ret <= 0) {
-          goto end;
-        }
-        hs->state = SSL3_ST_SW_KEY_EXCH_A;
-        break;
-
-      case SSL3_ST_SW_KEY_EXCH_A:
-        if (hs->server_params_len > 0) {
-          ret = ssl3_send_server_key_exchange(hs);
-          if (ret <= 0) {
-            goto end;
-          }
-        }
-
-        hs->state = SSL3_ST_SW_SRVR_DONE_A;
-        break;
-
-      case SSL3_ST_SW_SRVR_DONE_A:
-        ret = ssl3_send_server_hello_done(hs);
-        if (ret <= 0) {
-          goto end;
-        }
-        hs->next_state = SSL3_ST_SR_CERT_A;
-        hs->state = SSL3_ST_SW_FLUSH;
-        break;
-
-      case SSL3_ST_SR_CERT_A:
-        if (hs->cert_request) {
-          ret = ssl3_get_client_certificate(hs);
-          if (ret <= 0) {
-            goto end;
-          }
-        }
-        hs->state = SSL3_ST_VERIFY_CLIENT_CERT;
-        break;
-
-      case SSL3_ST_VERIFY_CLIENT_CERT:
-        if (sk_CRYPTO_BUFFER_num(hs->new_session->certs) > 0) {
-          switch (ssl_verify_peer_cert(hs)) {
-            case ssl_verify_ok:
-              break;
-            case ssl_verify_invalid:
-              ret = -1;
-              goto end;
-            case ssl_verify_retry:
-              ssl->rwstate = SSL_CERTIFICATE_VERIFY;
-              ret = -1;
-              goto end;
-          }
-        }
-        hs->state = SSL3_ST_SR_KEY_EXCH_A;
-        break;
-
-      case SSL3_ST_SR_KEY_EXCH_A:
-        ret = ssl3_get_client_key_exchange(hs);
-        if (ret <= 0) {
-          goto end;
-        }
-        hs->state = SSL3_ST_SR_CERT_VRFY_A;
-        break;
-
-      case SSL3_ST_SR_CERT_VRFY_A:
-        ret = ssl3_get_cert_verify(hs);
-        if (ret <= 0) {
-          goto end;
-        }
-
-        hs->state = SSL3_ST_SR_CHANGE;
-        break;
-
-      case SSL3_ST_SR_CHANGE:
-        ret = ssl->method->read_change_cipher_spec(ssl);
-        if (ret <= 0) {
-          goto end;
-        }
-
-        if (!tls1_change_cipher_state(hs, SSL3_CHANGE_CIPHER_SERVER_READ)) {
-          ret = -1;
-          goto end;
-        }
-
-        hs->state = SSL3_ST_SR_NEXT_PROTO_A;
-        break;
-
-      case SSL3_ST_SR_NEXT_PROTO_A:
-        if (hs->next_proto_neg_seen) {
-          ret = ssl3_get_next_proto(hs);
-          if (ret <= 0) {
-            goto end;
-          }
-        }
-        hs->state = SSL3_ST_SR_CHANNEL_ID_A;
-        break;
-
-      case SSL3_ST_SR_CHANNEL_ID_A:
-        if (ssl->s3->tlsext_channel_id_valid) {
-          ret = ssl3_get_channel_id(hs);
-          if (ret <= 0) {
-            goto end;
-          }
-        }
-        hs->state = SSL3_ST_SR_FINISHED_A;
-        break;
-
-      case SSL3_ST_SR_FINISHED_A:
-        ret = ssl3_get_finished(hs);
-        if (ret <= 0) {
-          goto end;
-        }
-
-        if (ssl->session != NULL) {
-          hs->state = SSL_ST_OK;
-        } else {
-          hs->state = SSL3_ST_SW_FINISHED_A;
-        }
-
-        /* If this is a full handshake with ChannelID then record the handshake
-         * hashes in |hs->new_session| in case we need them to verify a
-         * ChannelID signature on a resumption of this session in the future. */
-        if (ssl->session == NULL && ssl->s3->tlsext_channel_id_valid) {
-          ret = tls1_record_handshake_hashes_for_channel_id(hs);
-          if (ret <= 0) {
-            goto end;
-          }
-        }
-        break;
-
-      case SSL3_ST_SW_FINISHED_A:
-        ret = ssl3_send_server_finished(hs);
-        if (ret <= 0) {
-          goto end;
-        }
-        hs->state = SSL3_ST_SW_FLUSH;
-        if (ssl->session != NULL) {
-          hs->next_state = SSL3_ST_SR_CHANGE;
-        } else {
-          hs->next_state = SSL_ST_OK;
-        }
-        break;
-
-      case SSL3_ST_SW_FLUSH:
-        ret = ssl->method->flush_flight(ssl);
-        if (ret <= 0) {
-          goto end;
-        }
-
-        hs->state = hs->next_state;
-        break;
-
-      case SSL_ST_TLS13: {
-        int early_return = 0;
-        ret = tls13_handshake(hs, &early_return);
-        if (ret <= 0) {
-          goto end;
-        }
-
-        if (early_return) {
-          ret = 1;
-          goto end;
-        }
-
-        hs->state = SSL_ST_OK;
-        break;
-      }
-
-      case SSL_ST_OK:
-        ssl->method->on_handshake_complete(ssl);
-
-        /* If we aren't retaining peer certificates then we can discard it
-         * now. */
-        if (hs->new_session != NULL &&
-            ssl->retain_only_sha256_of_client_certs) {
-          sk_CRYPTO_BUFFER_pop_free(hs->new_session->certs, CRYPTO_BUFFER_free);
-          hs->new_session->certs = NULL;
-          ssl->ctx->x509_method->session_clear(hs->new_session.get());
-        }
-
-        SSL_SESSION_free(ssl->s3->established_session);
-        if (ssl->session != NULL) {
-          SSL_SESSION_up_ref(ssl->session);
-          ssl->s3->established_session = ssl->session;
-        } else {
-          ssl->s3->established_session = hs->new_session.release();
-          ssl->s3->established_session->not_resumable = 0;
-        }
-
-        ssl->s3->initial_handshake_complete = 1;
-        ssl_update_cache(hs, SSL_SESS_CACHE_SERVER);
-
-        ssl_do_info_callback(ssl, SSL_CB_HANDSHAKE_DONE, 1);
-        ret = 1;
-        goto end;
-
-      default:
-        OPENSSL_PUT_ERROR(SSL, SSL_R_UNKNOWN_STATE);
-        ret = -1;
-        goto end;
-    }
-
-    if (hs->state != state) {
-      ssl_do_info_callback(ssl, SSL_CB_ACCEPT_LOOP, 1);
-    }
-  }
-
-end:
-  ssl_do_info_callback(ssl, SSL_CB_ACCEPT_EXIT, ret);
-  return ret;
-}
+enum ssl_server_hs_state_t {
+  state_start_accept = 0,
+  state_read_client_hello,
+  state_select_certificate,
+  state_tls13,
+  state_select_parameters,
+  state_send_server_hello,
+  state_send_server_certificate,
+  state_send_server_key_exchange,
+  state_send_server_hello_done,
+  state_read_client_certificate,
+  state_verify_client_certificate,
+  state_read_client_key_exchange,
+  state_read_client_certificate_verify,
+  state_read_change_cipher_spec,
+  state_process_change_cipher_spec,
+  state_read_next_proto,
+  state_read_channel_id,
+  state_read_client_finished,
+  state_send_server_finished,
+  state_finish_server_handshake,
+  state_done,
+};
 
 int ssl_client_cipher_list_contains_cipher(const SSL_CLIENT_HELLO *client_hello,
                                            uint16_t id) {
@@ -486,18 +231,18 @@
       return 0;
     }
   } else {
-    /* Convert the ClientHello version to an equivalent supported_versions
-     * extension. */
+    // Convert the ClientHello version to an equivalent supported_versions
+    // extension.
     static const uint8_t kTLSVersions[] = {
-        0x03, 0x03, /* TLS 1.2 */
-        0x03, 0x02, /* TLS 1.1 */
-        0x03, 0x01, /* TLS 1 */
-        0x03, 0x00, /* SSL 3 */
+        0x03, 0x03,  // TLS 1.2
+        0x03, 0x02,  // TLS 1.1
+        0x03, 0x01,  // TLS 1
+        0x03, 0x00,  // SSL 3
     };
 
     static const uint8_t kDTLSVersions[] = {
-        0xfe, 0xfd, /* DTLS 1.2 */
-        0xfe, 0xff, /* DTLS 1.0 */
+        0xfe, 0xfd,  // DTLS 1.2
+        0xfe, 0xff,  // DTLS 1.0
     };
 
     size_t versions_len = 0;
@@ -528,11 +273,11 @@
     return 0;
   }
 
-  /* At this point, the connection's version is known and |ssl->version| is
-   * fixed. Begin enforcing the record-layer version. */
-  ssl->s3->have_version = 1;
+  // At this point, the connection's version is known and |ssl->version| is
+  // fixed. Begin enforcing the record-layer version.
+  ssl->s3->have_version = true;
 
-  /* Handle FALLBACK_SCSV. */
+  // Handle FALLBACK_SCSV.
   if (ssl_client_cipher_list_contains_cipher(client_hello,
                                              SSL3_CK_FALLBACK_SCSV & 0xffff) &&
       ssl3_protocol_version(ssl) < hs->max_version) {
@@ -574,10 +319,10 @@
   return sk;
 }
 
-/* ssl_get_compatible_server_ciphers determines the key exchange and
- * authentication cipher suite masks compatible with the server configuration
- * and current ClientHello parameters of |hs|. It sets |*out_mask_k| to the key
- * exchange mask and |*out_mask_a| to the authentication mask. */
+// ssl_get_compatible_server_ciphers determines the key exchange and
+// authentication cipher suite masks compatible with the server configuration
+// and current ClientHello parameters of |hs|. It sets |*out_mask_k| to the key
+// exchange mask and |*out_mask_a| to the authentication mask.
 static void ssl_get_compatible_server_ciphers(SSL_HANDSHAKE *hs,
                                               uint32_t *out_mask_k,
                                               uint32_t *out_mask_a) {
@@ -592,13 +337,13 @@
     }
   }
 
-  /* Check for a shared group to consider ECDHE ciphers. */
+  // Check for a shared group to consider ECDHE ciphers.
   uint16_t unused;
   if (tls1_get_shared_group(hs, &unused)) {
     mask_k |= SSL_kECDHE;
   }
 
-  /* PSK requires a server callback. */
+  // PSK requires a server callback.
   if (ssl->psk_server_callback != NULL) {
     mask_k |= SSL_kPSK;
     mask_a |= SSL_aPSK;
@@ -613,13 +358,13 @@
     const struct ssl_cipher_preference_list_st *server_pref) {
   SSL *const ssl = hs->ssl;
   STACK_OF(SSL_CIPHER) *prio, *allow;
-  /* in_group_flags will either be NULL, or will point to an array of bytes
-   * which indicate equal-preference groups in the |prio| stack. See the
-   * comment about |in_group_flags| in the |ssl_cipher_preference_list_st|
-   * struct. */
+  // in_group_flags will either be NULL, or will point to an array of bytes
+  // which indicate equal-preference groups in the |prio| stack. See the
+  // comment about |in_group_flags| in the |ssl_cipher_preference_list_st|
+  // struct.
   const uint8_t *in_group_flags;
-  /* group_min contains the minimal index so far found in a group, or -1 if no
-   * such value exists yet. */
+  // group_min contains the minimal index so far found in a group, or -1 if no
+  // such value exists yet.
   int group_min = -1;
 
   UniquePtr<STACK_OF(SSL_CIPHER)> client_pref =
@@ -645,17 +390,17 @@
     const SSL_CIPHER *c = sk_SSL_CIPHER_value(prio, i);
 
     size_t cipher_index;
-    if (/* Check if the cipher is supported for the current version. */
+    if (// Check if the cipher is supported for the current version.
         SSL_CIPHER_get_min_version(c) <= ssl3_protocol_version(ssl) &&
         ssl3_protocol_version(ssl) <= SSL_CIPHER_get_max_version(c) &&
-        /* Check the cipher is supported for the server configuration. */
+        // Check the cipher is supported for the server configuration.
         (c->algorithm_mkey & mask_k) &&
         (c->algorithm_auth & mask_a) &&
-        /* Check the cipher is in the |allow| list. */
+        // Check the cipher is in the |allow| list.
         sk_SSL_CIPHER_find(allow, &cipher_index, c)) {
       if (in_group_flags != NULL && in_group_flags[i] == 1) {
-        /* This element of |prio| is in a group. Update the minimum index found
-         * so far and continue looking. */
+        // This element of |prio| is in a group. Update the minimum index found
+        // so far and continue looking.
         if (group_min == -1 || (size_t)group_min > cipher_index) {
           group_min = cipher_index;
         }
@@ -668,8 +413,8 @@
     }
 
     if (in_group_flags != NULL && in_group_flags[i] == 0 && group_min != -1) {
-      /* We are about to leave a group, but we found a match in it, so that's
-       * our answer. */
+      // We are about to leave a group, but we found a match in it, so that's
+      // our answer.
       return sk_SSL_CIPHER_value(allow, group_min);
     }
   }
@@ -677,191 +422,200 @@
   return nullptr;
 }
 
-static int ssl3_read_client_hello(SSL_HANDSHAKE *hs) {
+static enum ssl_hs_wait_t do_start_accept(SSL_HANDSHAKE *hs) {
+  ssl_do_info_callback(hs->ssl, SSL_CB_HANDSHAKE_START, 1);
+  hs->state = state_read_client_hello;
+  return ssl_hs_ok;
+}
+
+static enum ssl_hs_wait_t do_read_client_hello(SSL_HANDSHAKE *hs) {
   SSL *const ssl = hs->ssl;
+
   SSLMessage msg;
-  int ret = ssl_read_message(ssl, &msg);
-  if (ret <= 0) {
-    return ret;
+  if (!ssl->method->get_message(ssl, &msg)) {
+    return ssl_hs_read_message;
   }
+
   if (!ssl_check_message_type(ssl, msg, SSL3_MT_CLIENT_HELLO)) {
-    return -1;
+    return ssl_hs_error;
   }
 
   SSL_CLIENT_HELLO client_hello;
   if (!ssl_client_hello_init(ssl, &client_hello, msg)) {
     OPENSSL_PUT_ERROR(SSL, SSL_R_DECODE_ERROR);
     ssl3_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_DECODE_ERROR);
-    return -1;
+    return ssl_hs_error;
   }
 
-  /* Run the early callback. */
+  // Run the early callback.
   if (ssl->ctx->select_certificate_cb != NULL) {
     switch (ssl->ctx->select_certificate_cb(&client_hello)) {
       case ssl_select_cert_retry:
-        ssl->rwstate = SSL_CERTIFICATE_SELECTION_PENDING;
-        return -1;
+        return ssl_hs_certificate_selection_pending;
 
       case ssl_select_cert_error:
-        /* Connection rejected. */
+        // Connection rejected.
         OPENSSL_PUT_ERROR(SSL, SSL_R_CONNECTION_REJECTED);
         ssl3_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_HANDSHAKE_FAILURE);
-        return -1;
+        return ssl_hs_error;
 
       default:
         /* fallthrough */;
     }
   }
 
-  /* Freeze the version range after the early callback. */
+  // Freeze the version range after the early callback.
   if (!ssl_get_version_range(ssl, &hs->min_version, &hs->max_version)) {
-    return -1;
+    return ssl_hs_error;
   }
 
   uint8_t alert = SSL_AD_DECODE_ERROR;
   if (!negotiate_version(hs, &alert, &client_hello)) {
     ssl3_send_alert(ssl, SSL3_AL_FATAL, alert);
-    return -1;
+    return ssl_hs_error;
   }
 
   hs->client_version = client_hello.version;
   if (client_hello.random_len != SSL3_RANDOM_SIZE) {
     OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR);
-    return -1;
+    return ssl_hs_error;
   }
   OPENSSL_memcpy(ssl->s3->client_random, client_hello.random,
                  client_hello.random_len);
 
-  /* Only null compression is supported. TLS 1.3 further requires the peer
-   * advertise no other compression. */
+  // Only null compression is supported. TLS 1.3 further requires the peer
+  // advertise no other compression.
   if (OPENSSL_memchr(client_hello.compression_methods, 0,
                      client_hello.compression_methods_len) == NULL ||
       (ssl3_protocol_version(ssl) >= TLS1_3_VERSION &&
        client_hello.compression_methods_len != 1)) {
     OPENSSL_PUT_ERROR(SSL, SSL_R_INVALID_COMPRESSION_LIST);
     ssl3_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_ILLEGAL_PARAMETER);
-    return -1;
+    return ssl_hs_error;
   }
 
-  /* TLS extensions. */
+  // TLS extensions.
   if (!ssl_parse_clienthello_tlsext(hs, &client_hello)) {
     OPENSSL_PUT_ERROR(SSL, SSL_R_PARSE_TLSEXT);
-    return -1;
+    return ssl_hs_error;
   }
 
-  return 1;
+  hs->state = state_select_certificate;
+  return ssl_hs_ok;
 }
 
-static int ssl3_select_certificate(SSL_HANDSHAKE *hs) {
+static enum ssl_hs_wait_t do_select_certificate(SSL_HANDSHAKE *hs) {
   SSL *const ssl = hs->ssl;
+
   SSLMessage msg;
-  int ret = ssl_read_message(ssl, &msg);
-  if (ret <= 0) {
-    return ret;
+  if (!ssl->method->get_message(ssl, &msg)) {
+    return ssl_hs_read_message;
   }
 
-  /* Call |cert_cb| to update server certificates if required. */
+  // Call |cert_cb| to update server certificates if required.
   if (ssl->cert->cert_cb != NULL) {
     int rv = ssl->cert->cert_cb(ssl, ssl->cert->cert_cb_arg);
     if (rv == 0) {
       OPENSSL_PUT_ERROR(SSL, SSL_R_CERT_CB_ERROR);
       ssl3_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_INTERNAL_ERROR);
-      return -1;
+      return ssl_hs_error;
     }
     if (rv < 0) {
-      ssl->rwstate = SSL_X509_LOOKUP;
-      return -1;
+      return ssl_hs_x509_lookup;
     }
   }
 
   if (!ssl_on_certificate_selected(hs)) {
-    return -1;
+    return ssl_hs_error;
   }
 
   if (ssl3_protocol_version(ssl) >= TLS1_3_VERSION) {
-    /* Jump to the TLS 1.3 state machine. */
-    hs->state = SSL_ST_TLS13;
-    hs->do_tls13_handshake = tls13_server_handshake;
-    return 1;
+    // Jump to the TLS 1.3 state machine.
+    hs->state = state_tls13;
+    return ssl_hs_ok;
   }
 
   SSL_CLIENT_HELLO client_hello;
   if (!ssl_client_hello_init(ssl, &client_hello, msg)) {
-    return -1;
+    return ssl_hs_error;
   }
 
-  /* Negotiate the cipher suite. This must be done after |cert_cb| so the
-   * certificate is finalized. */
+  // Negotiate the cipher suite. This must be done after |cert_cb| so the
+  // certificate is finalized.
   hs->new_cipher =
       ssl3_choose_cipher(hs, &client_hello, ssl_get_cipher_preferences(ssl));
   if (hs->new_cipher == NULL) {
     OPENSSL_PUT_ERROR(SSL, SSL_R_NO_SHARED_CIPHER);
     ssl3_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_HANDSHAKE_FAILURE);
-    return -1;
+    return ssl_hs_error;
   }
 
-  return 1;
+  hs->state = state_select_parameters;
+  return ssl_hs_ok;
 }
 
-static int ssl3_select_parameters(SSL_HANDSHAKE *hs) {
-  SSL *const ssl = hs->ssl;
-  SSLMessage msg;
-  int ret = ssl_read_message(ssl, &msg);
-  if (ret <= 0) {
-    return ret;
-  }
-  SSL_CLIENT_HELLO client_hello;
-  if (!ssl_client_hello_init(ssl, &client_hello, msg)) {
-    return -1;
+static enum ssl_hs_wait_t do_tls13(SSL_HANDSHAKE *hs) {
+  enum ssl_hs_wait_t wait = tls13_server_handshake(hs);
+  if (wait == ssl_hs_ok) {
+    hs->state = state_finish_server_handshake;
+    return ssl_hs_ok;
   }
 
-  /* Determine whether we are doing session resumption. */
+  return wait;
+}
+
+static enum ssl_hs_wait_t do_select_parameters(SSL_HANDSHAKE *hs) {
+  SSL *const ssl = hs->ssl;
+
+  SSLMessage msg;
+  if (!ssl->method->get_message(ssl, &msg)) {
+    return ssl_hs_read_message;
+  }
+
+  SSL_CLIENT_HELLO client_hello;
+  if (!ssl_client_hello_init(ssl, &client_hello, msg)) {
+    return ssl_hs_error;
+  }
+
+  // Determine whether we are doing session resumption.
   UniquePtr<SSL_SESSION> session;
-  int tickets_supported = 0, renew_ticket = 0;
-  switch (ssl_get_prev_session(ssl, &session, &tickets_supported, &renew_ticket,
-                               &client_hello)) {
-    case ssl_session_success:
-      break;
-    case ssl_session_error:
-      return -1;
-    case ssl_session_retry:
-      ssl->rwstate = SSL_PENDING_SESSION;
-      return -1;
-    case ssl_session_ticket_retry:
-      ssl->rwstate = SSL_PENDING_TICKET;
-      return -1;
+  bool tickets_supported = false, renew_ticket = false;
+  enum ssl_hs_wait_t wait = ssl_get_prev_session(
+      ssl, &session, &tickets_supported, &renew_ticket, &client_hello);
+  if (wait != ssl_hs_ok) {
+    return wait;
   }
 
   if (session) {
     if (session->extended_master_secret && !hs->extended_master_secret) {
-      /* A ClientHello without EMS that attempts to resume a session with EMS
-       * is fatal to the connection. */
+      // A ClientHello without EMS that attempts to resume a session with EMS
+      // is fatal to the connection.
       OPENSSL_PUT_ERROR(SSL, SSL_R_RESUMED_EMS_SESSION_WITHOUT_EMS_EXTENSION);
       ssl3_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_HANDSHAKE_FAILURE);
-      return -1;
+      return ssl_hs_error;
     }
 
     if (!ssl_session_is_resumable(hs, session.get()) ||
-        /* If the client offers the EMS extension, but the previous session
-         * didn't use it, then negotiate a new session. */
+        // If the client offers the EMS extension, but the previous session
+        // didn't use it, then negotiate a new session.
         hs->extended_master_secret != session->extended_master_secret) {
       session.reset();
     }
   }
 
   if (session) {
-    /* Use the old session. */
+    // Use the old session.
     hs->ticket_expected = renew_ticket;
     ssl->session = session.release();
-    ssl->s3->session_reused = 1;
+    ssl->s3->session_reused = true;
   } else {
     hs->ticket_expected = tickets_supported;
     ssl_set_session(ssl, NULL);
     if (!ssl_get_new_session(hs, 1 /* server */)) {
-      return -1;
+      return ssl_hs_error;
     }
 
-    /* Clear the session ID if we want the session to be single-use. */
+    // Clear the session ID if we want the session to be single-use.
     if (!(ssl->ctx->session_cache_mode & SSL_SESS_CACHE_SERVER)) {
       hs->new_session->session_id_length = 0;
     }
@@ -869,85 +623,87 @@
 
   if (ssl->ctx->dos_protection_cb != NULL &&
       ssl->ctx->dos_protection_cb(&client_hello) == 0) {
-    /* Connection rejected for DOS reasons. */
+    // Connection rejected for DOS reasons.
     OPENSSL_PUT_ERROR(SSL, SSL_R_CONNECTION_REJECTED);
     ssl3_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_INTERNAL_ERROR);
-    return -1;
+    return ssl_hs_error;
   }
 
   if (ssl->session == NULL) {
     hs->new_session->cipher = hs->new_cipher;
 
-    /* On new sessions, stash the SNI value in the session. */
+    // On new sessions, stash the SNI value in the session.
     if (hs->hostname != NULL) {
       OPENSSL_free(hs->new_session->tlsext_hostname);
       hs->new_session->tlsext_hostname = BUF_strdup(hs->hostname.get());
       if (hs->new_session->tlsext_hostname == NULL) {
         ssl3_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_INTERNAL_ERROR);
-        return -1;
+        return ssl_hs_error;
       }
     }
 
-    /* Determine whether to request a client certificate. */
+    // Determine whether to request a client certificate.
     hs->cert_request = !!(ssl->verify_mode & SSL_VERIFY_PEER);
-    /* Only request a certificate if Channel ID isn't negotiated. */
+    // Only request a certificate if Channel ID isn't negotiated.
     if ((ssl->verify_mode & SSL_VERIFY_PEER_IF_NO_OBC) &&
         ssl->s3->tlsext_channel_id_valid) {
-      hs->cert_request = 0;
+      hs->cert_request = false;
     }
-    /* CertificateRequest may only be sent in certificate-based ciphers. */
+    // CertificateRequest may only be sent in certificate-based ciphers.
     if (!ssl_cipher_uses_certificate_auth(hs->new_cipher)) {
-      hs->cert_request = 0;
+      hs->cert_request = false;
     }
 
     if (!hs->cert_request) {
-      /* OpenSSL returns X509_V_OK when no certificates are requested. This is
-       * classed by them as a bug, but it's assumed by at least NGINX. */
+      // OpenSSL returns X509_V_OK when no certificates are requested. This is
+      // classed by them as a bug, but it's assumed by at least NGINX.
       hs->new_session->verify_result = X509_V_OK;
     }
   }
 
-  /* HTTP/2 negotiation depends on the cipher suite, so ALPN negotiation was
-   * deferred. Complete it now. */
+  // HTTP/2 negotiation depends on the cipher suite, so ALPN negotiation was
+  // deferred. Complete it now.
   uint8_t alert = SSL_AD_DECODE_ERROR;
   if (!ssl_negotiate_alpn(hs, &alert, &client_hello)) {
     ssl3_send_alert(ssl, SSL3_AL_FATAL, alert);
-    return -1;
+    return ssl_hs_error;
   }
 
-  /* Now that all parameters are known, initialize the handshake hash and hash
-   * the ClientHello. */
+  // Now that all parameters are known, initialize the handshake hash and hash
+  // the ClientHello.
   if (!hs->transcript.InitHash(ssl3_protocol_version(ssl), hs->new_cipher) ||
       !ssl_hash_message(hs, msg)) {
     ssl3_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_INTERNAL_ERROR);
-    return -1;
+    return ssl_hs_error;
   }
 
-  /* Release the handshake buffer if client authentication isn't required. */
+  // Release the handshake buffer if client authentication isn't required.
   if (!hs->cert_request) {
     hs->transcript.FreeBuffer();
   }
 
   ssl->method->next_message(ssl);
-  return 1;
+
+  hs->state = state_send_server_hello;
+  return ssl_hs_ok;
 }
 
-static int ssl3_send_server_hello(SSL_HANDSHAKE *hs) {
+static enum ssl_hs_wait_t do_send_server_hello(SSL_HANDSHAKE *hs) {
   SSL *const ssl = hs->ssl;
 
-  /* We only accept ChannelIDs on connections with ECDHE in order to avoid a
-   * known attack while we fix ChannelID itself. */
+  // We only accept ChannelIDs on connections with ECDHE in order to avoid a
+  // known attack while we fix ChannelID itself.
   if (ssl->s3->tlsext_channel_id_valid &&
       (hs->new_cipher->algorithm_mkey & SSL_kECDHE) == 0) {
-    ssl->s3->tlsext_channel_id_valid = 0;
+    ssl->s3->tlsext_channel_id_valid = false;
   }
 
-  /* If this is a resumption and the original handshake didn't support
-   * ChannelID then we didn't record the original handshake hashes in the
-   * session and so cannot resume with ChannelIDs. */
+  // If this is a resumption and the original handshake didn't support
+  // ChannelID then we didn't record the original handshake hashes in the
+  // session and so cannot resume with ChannelIDs.
   if (ssl->session != NULL &&
       ssl->session->original_handshake_hash_len == 0) {
-    ssl->s3->tlsext_channel_id_valid = 0;
+    ssl->s3->tlsext_channel_id_valid = false;
   }
 
   struct OPENSSL_timeval now;
@@ -957,11 +713,11 @@
   ssl->s3->server_random[2] = now.tv_sec >> 8;
   ssl->s3->server_random[3] = now.tv_sec;
   if (!RAND_bytes(ssl->s3->server_random + 4, SSL3_RANDOM_SIZE - 4)) {
-    return -1;
+    return ssl_hs_error;
   }
 
-  /* TODO(davidben): Implement the TLS 1.1 and 1.2 downgrade sentinels once TLS
-   * 1.3 is finalized and we are not implementing a draft version. */
+  // TODO(davidben): Implement the TLS 1.1 and 1.2 downgrade sentinels once TLS
+  // 1.3 is finalized and we are not implementing a draft version.
 
   const SSL_SESSION *session = hs->new_session.get();
   if (ssl->session != NULL) {
@@ -981,24 +737,29 @@
       !ssl_add_serverhello_tlsext(hs, &body) ||
       !ssl_add_message_cbb(ssl, cbb.get())) {
     OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR);
-    return -1;
+    return ssl_hs_error;
   }
 
-  return 1;
+  if (ssl->session != NULL) {
+    hs->state = state_send_server_finished;
+  } else {
+    hs->state = state_send_server_certificate;
+  }
+  return ssl_hs_ok;
 }
 
-static int ssl3_send_server_certificate(SSL_HANDSHAKE *hs) {
+static enum ssl_hs_wait_t do_send_server_certificate(SSL_HANDSHAKE *hs) {
   SSL *const ssl = hs->ssl;
   ScopedCBB cbb;
 
   if (ssl_cipher_uses_certificate_auth(hs->new_cipher)) {
     if (!ssl_has_certificate(ssl)) {
       OPENSSL_PUT_ERROR(SSL, SSL_R_NO_CERTIFICATE_SET);
-      return -1;
+      return ssl_hs_error;
     }
 
     if (!ssl3_output_cert_chain(ssl)) {
-      return -1;
+      return ssl_hs_error;
     }
 
     if (hs->certificate_status_expected) {
@@ -1012,107 +773,114 @@
                          CRYPTO_BUFFER_len(ssl->cert->ocsp_response)) ||
           !ssl_add_message_cbb(ssl, cbb.get())) {
         OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR);
-        return -1;
+        return ssl_hs_error;
       }
     }
   }
 
-  /* Assemble ServerKeyExchange parameters if needed. */
+  // Assemble ServerKeyExchange parameters if needed.
   uint32_t alg_k = hs->new_cipher->algorithm_mkey;
   uint32_t alg_a = hs->new_cipher->algorithm_auth;
   if (ssl_cipher_requires_server_key_exchange(hs->new_cipher) ||
       ((alg_a & SSL_aPSK) && ssl->psk_identity_hint)) {
 
-    /* Pre-allocate enough room to comfortably fit an ECDHE public key. Prepend
-     * the client and server randoms for the signing transcript. */
+    // Pre-allocate enough room to comfortably fit an ECDHE public key. Prepend
+    // the client and server randoms for the signing transcript.
     CBB child;
     if (!CBB_init(cbb.get(), SSL3_RANDOM_SIZE * 2 + 128) ||
         !CBB_add_bytes(cbb.get(), ssl->s3->client_random, SSL3_RANDOM_SIZE) ||
         !CBB_add_bytes(cbb.get(), ssl->s3->server_random, SSL3_RANDOM_SIZE)) {
-      return -1;
+      return ssl_hs_error;
     }
 
-    /* PSK ciphers begin with an identity hint. */
+    // PSK ciphers begin with an identity hint.
     if (alg_a & SSL_aPSK) {
       size_t len =
           (ssl->psk_identity_hint == NULL) ? 0 : strlen(ssl->psk_identity_hint);
       if (!CBB_add_u16_length_prefixed(cbb.get(), &child) ||
           !CBB_add_bytes(&child, (const uint8_t *)ssl->psk_identity_hint,
                          len)) {
-        return -1;
+        return ssl_hs_error;
       }
     }
 
     if (alg_k & SSL_kECDHE) {
-      /* Determine the group to use. */
+      // Determine the group to use.
       uint16_t group_id;
       if (!tls1_get_shared_group(hs, &group_id)) {
         OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR);
         ssl3_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_HANDSHAKE_FAILURE);
-        return -1;
+        return ssl_hs_error;
        }
       hs->new_session->group_id = group_id;
 
-      /* Set up ECDH, generate a key, and emit the public half. */
+      // Set up ECDH, generate a key, and emit the public half.
       hs->key_share = SSLKeyShare::Create(group_id);
       if (!hs->key_share ||
           !CBB_add_u8(cbb.get(), NAMED_CURVE_TYPE) ||
           !CBB_add_u16(cbb.get(), group_id) ||
           !CBB_add_u8_length_prefixed(cbb.get(), &child) ||
           !hs->key_share->Offer(&child)) {
-        return -1;
+        return ssl_hs_error;
       }
     } else {
       assert(alg_k & SSL_kPSK);
     }
 
     if (!CBB_finish(cbb.get(), &hs->server_params, &hs->server_params_len)) {
-      return -1;
+      return ssl_hs_error;
     }
   }
 
-  return 1;
+  hs->state = state_send_server_key_exchange;
+  return ssl_hs_ok;
 }
 
-static int ssl3_send_server_key_exchange(SSL_HANDSHAKE *hs) {
+static enum ssl_hs_wait_t do_send_server_key_exchange(SSL_HANDSHAKE *hs) {
   SSL *const ssl = hs->ssl;
+
+  if (hs->server_params_len == 0) {
+    hs->state = state_send_server_hello_done;
+    return ssl_hs_ok;
+  }
+
   ScopedCBB cbb;
   CBB body, child;
   if (!ssl->method->init_message(ssl, cbb.get(), &body,
                                  SSL3_MT_SERVER_KEY_EXCHANGE) ||
-      /* |hs->server_params| contains a prefix for signing. */
+      // |hs->server_params| contains a prefix for signing.
       hs->server_params_len < 2 * SSL3_RANDOM_SIZE ||
       !CBB_add_bytes(&body, hs->server_params + 2 * SSL3_RANDOM_SIZE,
                      hs->server_params_len - 2 * SSL3_RANDOM_SIZE)) {
-    return -1;
+    return ssl_hs_error;
   }
 
-  /* Add a signature. */
+  // Add a signature.
   if (ssl_cipher_uses_certificate_auth(hs->new_cipher)) {
     if (!ssl_has_private_key(ssl)) {
       ssl3_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_INTERNAL_ERROR);
-      return -1;
+      return ssl_hs_error;
     }
 
-    /* Determine the signature algorithm. */
+    // Determine the signature algorithm.
     uint16_t signature_algorithm;
     if (!tls1_choose_signature_algorithm(hs, &signature_algorithm)) {
-      return -1;
+      return ssl_hs_error;
     }
     if (ssl3_protocol_version(ssl) >= TLS1_2_VERSION) {
       if (!CBB_add_u16(&body, signature_algorithm)) {
         OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR);
         ssl3_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_INTERNAL_ERROR);
-        return -1;
+        return ssl_hs_error;
       }
     }
 
-    /* Add space for the signature. */
+    // Add space for the signature.
     const size_t max_sig_len = EVP_PKEY_size(hs->local_pubkey.get());
     uint8_t *ptr;
     if (!CBB_add_u16_length_prefixed(&body, &child) ||
         !CBB_reserve(&child, &ptr, max_sig_len)) {
-      return -1;
+      return ssl_hs_error;
     }
 
     size_t sig_len;
@@ -1121,30 +889,31 @@
                                  hs->server_params_len)) {
       case ssl_private_key_success:
         if (!CBB_did_write(&child, sig_len)) {
-          return -1;
+          return ssl_hs_error;
         }
         break;
       case ssl_private_key_failure:
-        return -1;
+        return ssl_hs_error;
       case ssl_private_key_retry:
-        ssl->rwstate = SSL_PRIVATE_KEY_OPERATION;
-        return -1;
+        return ssl_hs_private_key_operation;
     }
   }
 
   if (!ssl_add_message_cbb(ssl, cbb.get())) {
-    return -1;
+    return ssl_hs_error;
   }
 
   OPENSSL_free(hs->server_params);
   hs->server_params = NULL;
   hs->server_params_len = 0;
 
-  return 1;
+  hs->state = state_send_server_hello_done;
+  return ssl_hs_ok;
 }
 
-static int ssl3_send_server_hello_done(SSL_HANDSHAKE *hs) {
+static enum ssl_hs_wait_t do_send_server_hello_done(SSL_HANDSHAKE *hs) {
   SSL *const ssl = hs->ssl;
+
   ScopedCBB cbb;
   CBB body;
 
@@ -1162,7 +931,7 @@
         !ssl_add_client_CA_list(ssl, &body) ||
         !ssl_add_message_cbb(ssl, cbb.get())) {
       OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR);
-      return -1;
+      return ssl_hs_error;
     }
   }
 
@@ -1170,46 +939,51 @@
                                  SSL3_MT_SERVER_HELLO_DONE) ||
       !ssl_add_message_cbb(ssl, cbb.get())) {
     OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR);
-    return -1;
+    return ssl_hs_error;
   }
 
-  return 1;
+  hs->state = state_read_client_certificate;
+  return ssl_hs_flush;
 }
 
-static int ssl3_get_client_certificate(SSL_HANDSHAKE *hs) {
+static enum ssl_hs_wait_t do_read_client_certificate(SSL_HANDSHAKE *hs) {
   SSL *const ssl = hs->ssl;
-  assert(hs->cert_request);
+
+  if (!hs->cert_request) {
+    hs->state = state_verify_client_certificate;
+    return ssl_hs_ok;
+  }
 
   SSLMessage msg;
-  int ret = ssl_read_message(ssl, &msg);
-  if (ret <= 0) {
-    return ret;
+  if (!ssl->method->get_message(ssl, &msg)) {
+    return ssl_hs_read_message;
   }
 
   if (msg.type != SSL3_MT_CERTIFICATE) {
     if (ssl->version == SSL3_VERSION &&
         msg.type == SSL3_MT_CLIENT_KEY_EXCHANGE) {
-      /* In SSL 3.0, the Certificate message is omitted to signal no
-       * certificate. */
+      // In SSL 3.0, the Certificate message is omitted to signal no
+      // certificate.
       if (ssl->verify_mode & SSL_VERIFY_FAIL_IF_NO_PEER_CERT) {
         OPENSSL_PUT_ERROR(SSL, SSL_R_PEER_DID_NOT_RETURN_A_CERTIFICATE);
         ssl3_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_HANDSHAKE_FAILURE);
-        return -1;
+        return ssl_hs_error;
       }
 
-      /* OpenSSL returns X509_V_OK when no certificates are received. This is
-       * classed by them as a bug, but it's assumed by at least NGINX. */
+      // OpenSSL returns X509_V_OK when no certificates are received. This is
+      // classed by them as a bug, but it's assumed by at least NGINX.
       hs->new_session->verify_result = X509_V_OK;
-      return 1;
+      hs->state = state_verify_client_certificate;
+      return ssl_hs_ok;
     }
 
     OPENSSL_PUT_ERROR(SSL, SSL_R_UNEXPECTED_MESSAGE);
     ssl3_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_UNEXPECTED_MESSAGE);
-    return -1;
+    return ssl_hs_error;
   }
 
   if (!ssl_hash_message(hs, msg)) {
-    return -1;
+    return ssl_hs_error;
   }
 
   CBS certificate_msg = msg.body;
@@ -1221,7 +995,7 @@
                                 : NULL,
                             &certificate_msg, ssl->ctx->pool)) {
     ssl3_send_alert(ssl, SSL3_AL_FATAL, alert);
-    return -1;
+    return ssl_hs_error;
   }
   sk_CRYPTO_BUFFER_pop_free(hs->new_session->certs, CRYPTO_BUFFER_free);
   hs->new_session->certs = chain.release();
@@ -1230,66 +1004,84 @@
       !ssl->ctx->x509_method->session_cache_objects(hs->new_session.get())) {
     OPENSSL_PUT_ERROR(SSL, SSL_R_DECODE_ERROR);
     ssl3_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_DECODE_ERROR);
-    return -1;
+    return ssl_hs_error;
   }
 
   if (sk_CRYPTO_BUFFER_num(hs->new_session->certs) == 0) {
-    /* No client certificate so the handshake buffer may be discarded. */
+    // No client certificate so the handshake buffer may be discarded.
     hs->transcript.FreeBuffer();
 
-    /* In SSL 3.0, sending no certificate is signaled by omitting the
-     * Certificate message. */
+    // In SSL 3.0, sending no certificate is signaled by omitting the
+    // Certificate message.
     if (ssl->version == SSL3_VERSION) {
       OPENSSL_PUT_ERROR(SSL, SSL_R_NO_CERTIFICATES_RETURNED);
       ssl3_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_HANDSHAKE_FAILURE);
-      return -1;
+      return ssl_hs_error;
     }
 
     if (ssl->verify_mode & SSL_VERIFY_FAIL_IF_NO_PEER_CERT) {
-      /* Fail for TLS only if we required a certificate */
+      // Fail for TLS only if we required a certificate
       OPENSSL_PUT_ERROR(SSL, SSL_R_PEER_DID_NOT_RETURN_A_CERTIFICATE);
       ssl3_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_HANDSHAKE_FAILURE);
-      return -1;
+      return ssl_hs_error;
     }
 
-    /* OpenSSL returns X509_V_OK when no certificates are received. This is
-     * classed by them as a bug, but it's assumed by at least NGINX. */
+    // OpenSSL returns X509_V_OK when no certificates are received. This is
+    // classed by them as a bug, but it's assumed by at least NGINX.
     hs->new_session->verify_result = X509_V_OK;
   } else if (ssl->retain_only_sha256_of_client_certs) {
-    /* The hash will have been filled in. */
+    // The hash will have been filled in.
     hs->new_session->peer_sha256_valid = 1;
   }
 
   ssl->method->next_message(ssl);
-  return 1;
+  hs->state = state_verify_client_certificate;
+  return ssl_hs_ok;
 }
 
-static int ssl3_get_client_key_exchange(SSL_HANDSHAKE *hs) {
+static enum ssl_hs_wait_t do_verify_client_certificate(SSL_HANDSHAKE *hs) {
+  if (sk_CRYPTO_BUFFER_num(hs->new_session->certs) > 0) {
+    switch (ssl_verify_peer_cert(hs)) {
+      case ssl_verify_ok:
+        break;
+      case ssl_verify_invalid:
+        return ssl_hs_error;
+      case ssl_verify_retry:
+        return ssl_hs_certificate_verify;
+    }
+  }
+
+  hs->state = state_read_client_key_exchange;
+  return ssl_hs_ok;
+}
+
+static enum ssl_hs_wait_t do_read_client_key_exchange(SSL_HANDSHAKE *hs) {
   SSL *const ssl = hs->ssl;
+
+  ssl_hs_wait_t ret = ssl_hs_error;
   uint8_t *premaster_secret = NULL;
   size_t premaster_secret_len = 0;
   uint8_t *decrypt_buf = NULL;
 
   SSLMessage msg;
-  int ret = ssl_read_message(ssl, &msg);
-  if (ret <= 0) {
-    return ret;
+  if (!ssl->method->get_message(ssl, &msg)) {
+    return ssl_hs_read_message;
   }
 
   if (!ssl_check_message_type(ssl, msg, SSL3_MT_CLIENT_KEY_EXCHANGE)) {
-    return -1;
+    return ssl_hs_error;
   }
 
   CBS client_key_exchange = msg.body;
   uint32_t alg_k = hs->new_cipher->algorithm_mkey;
   uint32_t alg_a = hs->new_cipher->algorithm_auth;
 
-  /* If using a PSK key exchange, parse the PSK identity. */
+  // If using a PSK key exchange, parse the PSK identity.
   if (alg_a & SSL_aPSK) {
     CBS psk_identity;
 
-    /* If using PSK, the ClientKeyExchange contains a psk_identity. If PSK,
-     * then this is the only field in the message. */
+    // If using PSK, the ClientKeyExchange contains a psk_identity. If PSK,
+    // then this is the only field in the message.
     if (!CBS_get_u16_length_prefixed(&client_key_exchange, &psk_identity) ||
         ((alg_k & SSL_kPSK) && CBS_len(&client_key_exchange) != 0)) {
       OPENSSL_PUT_ERROR(SSL, SSL_R_DECODE_ERROR);
@@ -1311,8 +1103,8 @@
     }
   }
 
-  /* Depending on the key exchange method, compute |premaster_secret| and
-   * |premaster_secret_len|. */
+  // Depending on the key exchange method, compute |premaster_secret| and
+  // |premaster_secret_len|.
   if (alg_k & SSL_kRSA) {
     CBS encrypted_premaster_secret;
     if (ssl->version > SSL3_VERSION) {
@@ -1327,7 +1119,7 @@
       encrypted_premaster_secret = client_key_exchange;
     }
 
-    /* Allocate a buffer large enough for an RSA decryption. */
+    // Allocate a buffer large enough for an RSA decryption.
     const size_t rsa_size = EVP_PKEY_size(hs->local_pubkey.get());
     decrypt_buf = (uint8_t *)OPENSSL_malloc(rsa_size);
     if (decrypt_buf == NULL) {
@@ -1335,8 +1127,8 @@
       goto err;
     }
 
-    /* Decrypt with no padding. PKCS#1 padding will be removed as part of the
-     * timing-sensitive code below. */
+    // Decrypt with no padding. PKCS#1 padding will be removed as part of the
+    // timing-sensitive code below.
     size_t decrypt_len;
     switch (ssl_private_key_decrypt(hs, decrypt_buf, &decrypt_len, rsa_size,
                                     CBS_data(&encrypted_premaster_secret),
@@ -1346,7 +1138,7 @@
       case ssl_private_key_failure:
         goto err;
       case ssl_private_key_retry:
-        ssl->rwstate = SSL_PRIVATE_KEY_OPERATION;
+        ret = ssl_hs_private_key_operation;
         goto err;
     }
 
@@ -1356,8 +1148,8 @@
       goto err;
     }
 
-    /* Prepare a random premaster, to be used on invalid padding. See RFC 5246,
-     * section 7.4.7.1. */
+    // Prepare a random premaster, to be used on invalid padding. See RFC 5246,
+    // section 7.4.7.1.
     premaster_secret_len = SSL_MAX_MASTER_KEY_LENGTH;
     premaster_secret = (uint8_t *)OPENSSL_malloc(premaster_secret_len);
     if (premaster_secret == NULL) {
@@ -1368,15 +1160,15 @@
       goto err;
     }
 
-    /* The smallest padded premaster is 11 bytes of overhead. Small keys are
-     * publicly invalid. */
+    // The smallest padded premaster is 11 bytes of overhead. Small keys are
+    // publicly invalid.
     if (decrypt_len < 11 + premaster_secret_len) {
       OPENSSL_PUT_ERROR(SSL, SSL_R_DECRYPTION_FAILED);
       ssl3_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_DECRYPT_ERROR);
       goto err;
     }
 
-    /* Check the padding. See RFC 3447, section 7.2.2. */
+    // Check the padding. See RFC 3447, section 7.2.2.
     size_t padding_len = decrypt_len - premaster_secret_len;
     uint8_t good = constant_time_eq_int_8(decrypt_buf[0], 0) &
                    constant_time_eq_int_8(decrypt_buf[1], 2);
@@ -1385,15 +1177,15 @@
     }
     good &= constant_time_is_zero_8(decrypt_buf[padding_len - 1]);
 
-    /* The premaster secret must begin with |client_version|. This too must be
-     * checked in constant time (http://eprint.iacr.org/2003/052/). */
+    // The premaster secret must begin with |client_version|. This too must be
+    // checked in constant time (http://eprint.iacr.org/2003/052/).
     good &= constant_time_eq_8(decrypt_buf[padding_len],
                                (unsigned)(hs->client_version >> 8));
     good &= constant_time_eq_8(decrypt_buf[padding_len + 1],
                                (unsigned)(hs->client_version & 0xff));
 
-    /* Select, in constant time, either the decrypted premaster or the random
-     * premaster based on |good|. */
+    // Select, in constant time, either the decrypted premaster or the random
+    // premaster based on |good|.
     for (size_t i = 0; i < premaster_secret_len; i++) {
       premaster_secret[i] = constant_time_select_8(
           good, decrypt_buf[padding_len + i], premaster_secret[i]);
@@ -1402,7 +1194,7 @@
     OPENSSL_free(decrypt_buf);
     decrypt_buf = NULL;
   } else if (alg_k & SSL_kECDHE) {
-    /* Parse the ClientKeyExchange. */
+    // Parse the ClientKeyExchange.
     CBS peer_key;
     if (!CBS_get_u8_length_prefixed(&client_key_exchange, &peer_key) ||
         CBS_len(&client_key_exchange) != 0) {
@@ -1411,7 +1203,7 @@
       goto err;
     }
 
-    /* Compute the premaster. */
+    // Compute the premaster.
     uint8_t alert = SSL_AD_DECODE_ERROR;
     if (!hs->key_share->Finish(&premaster_secret, &premaster_secret_len, &alert,
                                CBS_data(&peer_key), CBS_len(&peer_key))) {
@@ -1419,7 +1211,7 @@
       goto err;
     }
 
-    /* The key exchange state may now be discarded. */
+    // The key exchange state may now be discarded.
     hs->key_share.reset();
   } else if (!(alg_k & SSL_kPSK)) {
     OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR);
@@ -1427,8 +1219,8 @@
     goto err;
   }
 
-  /* For a PSK cipher suite, the actual pre-master secret is combined with the
-   * pre-shared key. */
+  // For a PSK cipher suite, the actual pre-master secret is combined with the
+  // pre-shared key.
   if (alg_a & SSL_aPSK) {
     if (ssl->psk_server_callback == NULL) {
       OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR);
@@ -1436,7 +1228,7 @@
       goto err;
     }
 
-    /* Look up the key for the identity. */
+    // Look up the key for the identity.
     uint8_t psk[PSK_MAX_PSK_LEN];
     unsigned psk_len = ssl->psk_server_callback(
         ssl, hs->new_session->psk_identity, psk, sizeof(psk));
@@ -1445,15 +1237,15 @@
       ssl3_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_INTERNAL_ERROR);
       goto err;
     } else if (psk_len == 0) {
-      /* PSK related to the given identity not found */
+      // PSK related to the given identity not found.
       OPENSSL_PUT_ERROR(SSL, SSL_R_PSK_IDENTITY_NOT_FOUND);
       ssl3_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_UNKNOWN_PSK_IDENTITY);
       goto err;
     }
 
     if (alg_k & SSL_kPSK) {
-      /* In plain PSK, other_secret is a block of 0s with the same length as the
-       * pre-shared key. */
+      // In plain PSK, other_secret is a block of 0s with the same length as the
+      // pre-shared key.
       premaster_secret_len = psk_len;
       premaster_secret = (uint8_t *)OPENSSL_malloc(premaster_secret_len);
       if (premaster_secret == NULL) {
@@ -1488,7 +1280,7 @@
     goto err;
   }
 
-  /* Compute the master secret */
+  // Compute the master secret.
   hs->new_session->master_key_length = tls1_generate_master_secret(
       hs, hs->new_session->master_key, premaster_secret, premaster_secret_len);
   if (hs->new_session->master_key_length == 0) {
@@ -1496,10 +1288,9 @@
   }
   hs->new_session->extended_master_secret = hs->extended_master_secret;
 
-  OPENSSL_cleanse(premaster_secret, premaster_secret_len);
-  OPENSSL_free(premaster_secret);
   ssl->method->next_message(ssl);
-  return 1;
+  hs->state = state_read_client_certificate_verify;
+  ret = ssl_hs_ok;
 
 err:
   if (premaster_secret != NULL) {
@@ -1508,70 +1299,70 @@
   }
   OPENSSL_free(decrypt_buf);
 
-  return -1;
+  return ret;
+
 }
 
-static int ssl3_get_cert_verify(SSL_HANDSHAKE *hs) {
+static enum ssl_hs_wait_t do_read_client_certificate_verify(SSL_HANDSHAKE *hs) {
   SSL *const ssl = hs->ssl;
 
-  /* Only RSA and ECDSA client certificates are supported, so a
-   * CertificateVerify is required if and only if there's a client certificate.
-   * */
+  // Only RSA and ECDSA client certificates are supported, so a
+  // CertificateVerify is required if and only if there's a client certificate.
   if (!hs->peer_pubkey) {
     hs->transcript.FreeBuffer();
-    return 1;
+    hs->state = state_read_change_cipher_spec;
+    return ssl_hs_ok;
   }
 
   SSLMessage msg;
-  int ret = ssl_read_message(ssl, &msg);
-  if (ret <= 0) {
-    return ret;
+  if (!ssl->method->get_message(ssl, &msg)) {
+    return ssl_hs_read_message;
   }
 
   if (!ssl_check_message_type(ssl, msg, SSL3_MT_CERTIFICATE_VERIFY)) {
-    return -1;
+    return ssl_hs_error;
   }
 
   CBS certificate_verify = msg.body, signature;
 
-  /* Determine the signature algorithm. */
+  // Determine the signature algorithm.
   uint16_t signature_algorithm = 0;
   if (ssl3_protocol_version(ssl) >= TLS1_2_VERSION) {
     if (!CBS_get_u16(&certificate_verify, &signature_algorithm)) {
       OPENSSL_PUT_ERROR(SSL, SSL_R_DECODE_ERROR);
       ssl3_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_DECODE_ERROR);
-      return -1;
+      return ssl_hs_error;
     }
     uint8_t alert = SSL_AD_DECODE_ERROR;
     if (!tls12_check_peer_sigalg(ssl, &alert, signature_algorithm)) {
       ssl3_send_alert(ssl, SSL3_AL_FATAL, alert);
-      return -1;
+      return ssl_hs_error;
     }
     hs->new_session->peer_signature_algorithm = signature_algorithm;
   } else if (!tls1_get_legacy_signature_algorithm(&signature_algorithm,
                                                   hs->peer_pubkey.get())) {
     OPENSSL_PUT_ERROR(SSL, SSL_R_PEER_ERROR_UNSUPPORTED_CERTIFICATE_TYPE);
     ssl3_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_UNSUPPORTED_CERTIFICATE);
-    return -1;
+    return ssl_hs_error;
   }
 
-  /* Parse and verify the signature. */
+  // Parse and verify the signature.
   if (!CBS_get_u16_length_prefixed(&certificate_verify, &signature) ||
       CBS_len(&certificate_verify) != 0) {
     OPENSSL_PUT_ERROR(SSL, SSL_R_DECODE_ERROR);
     ssl3_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_DECODE_ERROR);
-    return -1;
+    return ssl_hs_error;
   }
 
   int sig_ok;
-  /* The SSL3 construction for CertificateVerify does not decompose into a
-   * single final digest and signature, and must be special-cased. */
+  // The SSL3 construction for CertificateVerify does not decompose into a
+  // single final digest and signature, and must be special-cased.
   if (ssl3_protocol_version(ssl) == SSL3_VERSION) {
     uint8_t digest[EVP_MAX_MD_SIZE];
     size_t digest_len;
     if (!hs->transcript.GetSSL3CertVerifyHash(
             digest, &digest_len, hs->new_session.get(), signature_algorithm)) {
-      return -1;
+      return ssl_hs_error;
     }
 
     UniquePtr<EVP_PKEY_CTX> pctx(
@@ -1594,33 +1385,51 @@
   if (!sig_ok) {
     OPENSSL_PUT_ERROR(SSL, SSL_R_BAD_SIGNATURE);
     ssl3_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_DECRYPT_ERROR);
-    return -1;
+    return ssl_hs_error;
   }
 
-  /* The handshake buffer is no longer necessary, and we may hash the current
-   * message.*/
+  // The handshake buffer is no longer necessary, and we may hash the current
+  // message.
   hs->transcript.FreeBuffer();
   if (!ssl_hash_message(hs, msg)) {
-    return -1;
+    return ssl_hs_error;
   }
 
   ssl->method->next_message(ssl);
-  return 1;
+  hs->state = state_read_change_cipher_spec;
+  return ssl_hs_ok;
 }
 
-/* ssl3_get_next_proto reads a Next Protocol Negotiation handshake message. It
- * sets the next_proto member in s if found */
-static int ssl3_get_next_proto(SSL_HANDSHAKE *hs) {
+static enum ssl_hs_wait_t do_read_change_cipher_spec(SSL_HANDSHAKE *hs) {
+  hs->state = state_process_change_cipher_spec;
+  return ssl_hs_read_change_cipher_spec;
+}
+
+static enum ssl_hs_wait_t do_process_change_cipher_spec(SSL_HANDSHAKE *hs) {
+  if (!tls1_change_cipher_state(hs, SSL3_CHANGE_CIPHER_SERVER_READ)) {
+    return ssl_hs_error;
+  }
+
+  hs->state = state_read_next_proto;
+  return ssl_hs_ok;
+}
+
+static enum ssl_hs_wait_t do_read_next_proto(SSL_HANDSHAKE *hs) {
   SSL *const ssl = hs->ssl;
+
+  if (!hs->next_proto_neg_seen) {
+    hs->state = state_read_channel_id;
+    return ssl_hs_ok;
+  }
+
   SSLMessage msg;
-  int ret = ssl_read_message(ssl, &msg);
-  if (ret <= 0) {
-    return ret;
+  if (!ssl->method->get_message(ssl, &msg)) {
+    return ssl_hs_read_message;
   }
 
   if (!ssl_check_message_type(ssl, msg, SSL3_MT_NEXT_PROTO) ||
       !ssl_hash_message(hs, msg)) {
-    return -1;
+    return ssl_hs_error;
   }
 
   CBS next_protocol = msg.body, selected_protocol, padding;
@@ -1629,52 +1438,83 @@
       CBS_len(&next_protocol) != 0) {
     OPENSSL_PUT_ERROR(SSL, SSL_R_DECODE_ERROR);
     ssl3_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_DECODE_ERROR);
-    return -1;
+    return ssl_hs_error;
   }
 
   if (!CBS_stow(&selected_protocol, &ssl->s3->next_proto_negotiated,
                 &ssl->s3->next_proto_negotiated_len)) {
-    return -1;
+    return ssl_hs_error;
   }
 
   ssl->method->next_message(ssl);
-  return 1;
+  hs->state = state_read_channel_id;
+  return ssl_hs_ok;
 }
 
-/* ssl3_get_channel_id reads and verifies a ClientID handshake message. */
-static int ssl3_get_channel_id(SSL_HANDSHAKE *hs) {
+static enum ssl_hs_wait_t do_read_channel_id(SSL_HANDSHAKE *hs) {
   SSL *const ssl = hs->ssl;
+
+  if (!ssl->s3->tlsext_channel_id_valid) {
+    hs->state = state_read_client_finished;
+    return ssl_hs_ok;
+  }
+
   SSLMessage msg;
-  int ret = ssl_read_message(ssl, &msg);
-  if (ret <= 0) {
-    return ret;
+  if (!ssl->method->get_message(ssl, &msg)) {
+    return ssl_hs_read_message;
   }
 
   if (!ssl_check_message_type(ssl, msg, SSL3_MT_CHANNEL_ID) ||
       !tls1_verify_channel_id(hs, msg) ||
       !ssl_hash_message(hs, msg)) {
-    return -1;
+    return ssl_hs_error;
   }
+
   ssl->method->next_message(ssl);
-  return 1;
+  hs->state = state_read_client_finished;
+  return ssl_hs_ok;
 }
 
-static int ssl3_send_server_finished(SSL_HANDSHAKE *hs) {
+static enum ssl_hs_wait_t do_read_client_finished(SSL_HANDSHAKE *hs) {
+  SSL *const ssl = hs->ssl;
+  enum ssl_hs_wait_t wait = ssl_get_finished(hs);
+  if (wait != ssl_hs_ok) {
+    return wait;
+  }
+
+  if (ssl->session != NULL) {
+    hs->state = state_finish_server_handshake;
+  } else {
+    hs->state = state_send_server_finished;
+  }
+
+  // If this is a full handshake with ChannelID then record the handshake
+  // hashes in |hs->new_session| in case we need them to verify a
+  // ChannelID signature on a resumption of this session in the future.
+  if (ssl->session == NULL && ssl->s3->tlsext_channel_id_valid &&
+      !tls1_record_handshake_hashes_for_channel_id(hs)) {
+    return ssl_hs_error;
+  }
+
+  return ssl_hs_ok;
+}
+
+static enum ssl_hs_wait_t do_send_server_finished(SSL_HANDSHAKE *hs) {
   SSL *const ssl = hs->ssl;
 
   if (hs->ticket_expected) {
     const SSL_SESSION *session;
     UniquePtr<SSL_SESSION> session_copy;
     if (ssl->session == NULL) {
-      /* Fix the timeout to measure from the ticket issuance time. */
+      // Fix the timeout to measure from the ticket issuance time.
       ssl_session_rebase_time(ssl, hs->new_session.get());
       session = hs->new_session.get();
     } else {
-      /* We are renewing an existing session. Duplicate the session to adjust
-       * the timeout. */
+      // We are renewing an existing session. Duplicate the session to adjust
+      // the timeout.
       session_copy = SSL_SESSION_dup(ssl->session, SSL_SESSION_INCLUDE_NONAUTH);
       if (!session_copy) {
-        return -1;
+        return ssl_hs_error;
       }
 
       ssl_session_rebase_time(ssl, session_copy.get());
@@ -1689,16 +1529,186 @@
         !CBB_add_u16_length_prefixed(&body, &ticket) ||
         !ssl_encrypt_ticket(ssl, &ticket, session) ||
         !ssl_add_message_cbb(ssl, cbb.get())) {
-      return -1;
+      return ssl_hs_error;
     }
   }
 
   if (!ssl->method->add_change_cipher_spec(ssl) ||
-      !tls1_change_cipher_state(hs, SSL3_CHANGE_CIPHER_SERVER_WRITE)) {
-    return -1;
+      !tls1_change_cipher_state(hs, SSL3_CHANGE_CIPHER_SERVER_WRITE) ||
+      !ssl3_send_finished(hs)) {
+    return ssl_hs_error;
   }
 
-  return ssl3_send_finished(hs);
+  if (ssl->session != NULL) {
+    hs->state = state_read_change_cipher_spec;
+  } else {
+    hs->state = state_finish_server_handshake;
+  }
+  return ssl_hs_flush;
 }
 
-}  // namespace bssl
+static enum ssl_hs_wait_t do_finish_server_handshake(SSL_HANDSHAKE *hs) {
+  SSL *const ssl = hs->ssl;
+
+  ssl->method->on_handshake_complete(ssl);
+
+  // If we aren't retaining peer certificates then we can discard it now.
+  if (hs->new_session != NULL && ssl->retain_only_sha256_of_client_certs) {
+    sk_CRYPTO_BUFFER_pop_free(hs->new_session->certs, CRYPTO_BUFFER_free);
+    hs->new_session->certs = NULL;
+    ssl->ctx->x509_method->session_clear(hs->new_session.get());
+  }
+
+  SSL_SESSION_free(ssl->s3->established_session);
+  if (ssl->session != NULL) {
+    SSL_SESSION_up_ref(ssl->session);
+    ssl->s3->established_session = ssl->session;
+  } else {
+    ssl->s3->established_session = hs->new_session.release();
+    ssl->s3->established_session->not_resumable = 0;
+  }
+
+  hs->handshake_finalized = true;
+  ssl->s3->initial_handshake_complete = true;
+  ssl_update_cache(hs, SSL_SESS_CACHE_SERVER);
+
+  hs->state = state_done;
+  return ssl_hs_ok;
+}
+
+enum ssl_hs_wait_t ssl_server_handshake(SSL_HANDSHAKE *hs) {
+  while (hs->state != state_done) {
+    enum ssl_hs_wait_t ret = ssl_hs_error;
+    enum ssl_server_hs_state_t state =
+        static_cast<enum ssl_server_hs_state_t>(hs->state);
+    switch (state) {
+      case state_start_accept:
+        ret = do_start_accept(hs);
+        break;
+      case state_read_client_hello:
+        ret = do_read_client_hello(hs);
+        break;
+      case state_select_certificate:
+        ret = do_select_certificate(hs);
+        break;
+      case state_tls13:
+        ret = do_tls13(hs);
+        break;
+      case state_select_parameters:
+        ret = do_select_parameters(hs);
+        break;
+      case state_send_server_hello:
+        ret = do_send_server_hello(hs);
+        break;
+      case state_send_server_certificate:
+        ret = do_send_server_certificate(hs);
+        break;
+      case state_send_server_key_exchange:
+        ret = do_send_server_key_exchange(hs);
+        break;
+      case state_send_server_hello_done:
+        ret = do_send_server_hello_done(hs);
+        break;
+      case state_read_client_certificate:
+        ret = do_read_client_certificate(hs);
+        break;
+      case state_verify_client_certificate:
+        ret = do_verify_client_certificate(hs);
+        break;
+      case state_read_client_key_exchange:
+        ret = do_read_client_key_exchange(hs);
+        break;
+      case state_read_client_certificate_verify:
+        ret = do_read_client_certificate_verify(hs);
+        break;
+      case state_read_change_cipher_spec:
+        ret = do_read_change_cipher_spec(hs);
+        break;
+      case state_process_change_cipher_spec:
+        ret = do_process_change_cipher_spec(hs);
+        break;
+      case state_read_next_proto:
+        ret = do_read_next_proto(hs);
+        break;
+      case state_read_channel_id:
+        ret = do_read_channel_id(hs);
+        break;
+      case state_read_client_finished:
+        ret = do_read_client_finished(hs);
+        break;
+      case state_send_server_finished:
+        ret = do_send_server_finished(hs);
+        break;
+      case state_finish_server_handshake:
+        ret = do_finish_server_handshake(hs);
+        break;
+      case state_done:
+        ret = ssl_hs_ok;
+        break;
+    }
+
+    if (hs->state != state) {
+      ssl_do_info_callback(hs->ssl, SSL_CB_ACCEPT_LOOP, 1);
+    }
+
+    if (ret != ssl_hs_ok) {
+      return ret;
+    }
+  }
+
+  ssl_do_info_callback(hs->ssl, SSL_CB_HANDSHAKE_DONE, 1);
+  return ssl_hs_ok;
+}
+
+const char *ssl_server_handshake_state(SSL_HANDSHAKE *hs) {
+  enum ssl_server_hs_state_t state =
+      static_cast<enum ssl_server_hs_state_t>(hs->state);
+  switch (state) {
+    case state_start_accept:
+      return "TLS server start_accept";
+    case state_read_client_hello:
+      return "TLS server read_client_hello";
+    case state_select_certificate:
+      return "TLS server select_certificate";
+    case state_tls13:
+      return tls13_server_handshake_state(hs);
+    case state_select_parameters:
+      return "TLS server select_parameters";
+    case state_send_server_hello:
+      return "TLS server send_server_hello";
+    case state_send_server_certificate:
+      return "TLS server send_server_certificate";
+    case state_send_server_key_exchange:
+      return "TLS server send_server_key_exchange";
+    case state_send_server_hello_done:
+      return "TLS server send_server_hello_done";
+    case state_read_client_certificate:
+      return "TLS server read_client_certificate";
+    case state_verify_client_certificate:
+      return "TLS server verify_client_certificate";
+    case state_read_client_key_exchange:
+      return "TLS server read_client_key_exchange";
+    case state_read_client_certificate_verify:
+      return "TLS server read_client_certificate_verify";
+    case state_read_change_cipher_spec:
+      return "TLS server read_change_cipher_spec";
+    case state_process_change_cipher_spec:
+      return "TLS server process_change_cipher_spec";
+    case state_read_next_proto:
+      return "TLS server read_next_proto";
+    case state_read_channel_id:
+      return "TLS server read_channel_id";
+    case state_read_client_finished:
+      return "TLS server read_client_finished";
+    case state_send_server_finished:
+      return "TLS server send_server_finished";
+    case state_finish_server_handshake:
+      return "TLS server finish_server_handshake";
+    case state_done:
+      return "TLS server done";
+  }
+
+  return "TLS server unknown";
+}
+
+}