text: /* ssl/d1_srvr.c */
  /* 
   * DTLS implementation written by Nagendra Modadugu
   * (nagendra@cs.stanford.edu) for the OpenSSL project 2005.  
   */
  /* ====================================================================
   * Copyright (c) 1999-2007 The OpenSSL Project.  All rights reserved.
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions
   * are met:
   *
   * 1. Redistributions of source code must retain the above copyright
   *    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
   *    the documentation and/or other materials provided with the
   *    distribution.
   *
   * 3. All advertising materials mentioning features or use of this
   *    software must display the following acknowledgment:
   *    "This product includes software developed by the OpenSSL Project
   *    for use in the OpenSSL Toolkit. (http://www.OpenSSL.org/)"
   *
   * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
   *    endorse or promote products derived from this software without
   *    prior written permission. For written permission, please contact
   *    openssl-core@OpenSSL.org.
   *
   * 5. Products derived from this software may not be called "OpenSSL"
   *    nor may "OpenSSL" appear in their names without prior written
   *    permission of the OpenSSL Project.
   *
   * 6. Redistributions of any form whatsoever must retain the following
   *    acknowledgment:
   *    "This product includes software developed by the OpenSSL Project
   *    for use in the OpenSSL Toolkit (http://www.OpenSSL.org/)"
   *
   * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
   * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
   * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE OpenSSL PROJECT OR
   * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
   * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
   * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
   * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
   * STRICT 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.
   * ====================================================================
   *
   * This product includes cryptographic software written by Eric Young
   * (eay@cryptsoft.com).  This product includes software written by Tim
   * Hudson (tjh@cryptsoft.com).
   *
   */
  /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
   * All rights reserved.
   *
   * 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:
   * 1. Redistributions of source code must retain the copyright
   *    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 the
   *    documentation and/or other materials provided with the distribution.
   * 3. All advertising materials mentioning features or use of this software
   *    must display the following acknowledgement:
   *    "This product includes cryptographic software written by
   *     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 
   *    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
   * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
   * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   * 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
   * [including the GNU Public Licence.]
   */
  
  #include <stdio.h>
  #include "ssl_locl.h"
  #include <openssl/buffer.h>
  #include <openssl/rand.h>
  #include <openssl/objects.h>
  #include <openssl/evp.h>
  #include <openssl/x509.h>
  #include <openssl/md5.h>
  #include <openssl/bn.h>
  #ifndef OPENSSL_NO_DH
  #include <openssl/dh.h>
  #endif
  
  static const SSL_METHOD *dtls1_get_server_method(int ver);
  static int dtls1_send_hello_verify_request(SSL *s);
  
  static const SSL_METHOD *dtls1_get_server_method(int ver)
  	{
  	if (ver == DTLS1_VERSION)
  		return(DTLSv1_server_method());
  	else if (ver == DTLS1_2_VERSION)
  		return(DTLSv1_2_server_method());
  	else
  		return(NULL);
  	}
  
  IMPLEMENT_dtls1_meth_func(DTLS1_VERSION,
  			DTLSv1_server_method,
  			dtls1_accept,
  			ssl_undefined_function,
  			dtls1_get_server_method,
  			DTLSv1_enc_data)
  
  IMPLEMENT_dtls1_meth_func(DTLS1_2_VERSION,
  			DTLSv1_2_server_method,
  			dtls1_accept,
  			ssl_undefined_function,
  			dtls1_get_server_method,
  			DTLSv1_2_enc_data)
  
  IMPLEMENT_dtls1_meth_func(DTLS_ANY_VERSION,
  			DTLS_server_method,
  			dtls1_accept,
  			ssl_undefined_function,
  			dtls1_get_server_method,
  			DTLSv1_2_enc_data)
  
  int dtls1_accept(SSL *s)
  	{
  	BUF_MEM *buf;
  	unsigned long Time=(unsigned long)time(NULL);
  	void (*cb)(const SSL *ssl,int type,int val)=NULL;
  	unsigned long alg_k;
  	int ret= -1;
  	int new_state,state,skip=0;
  	int listen;
  #ifndef OPENSSL_NO_SCTP
  	unsigned char sctpauthkey[64];
  	char labelbuffer[sizeof(DTLS1_SCTP_AUTH_LABEL)];
  #endif
  
  	RAND_add(&Time,sizeof(Time),0);
  	ERR_clear_error();
  	clear_sys_error();
  
  	if (s->info_callback != NULL)
  		cb=s->info_callback;
  	else if (s->ctx->info_callback != NULL)
  		cb=s->ctx->info_callback;
  	
  	listen = s->d1->listen;
  
  	/* init things to blank */
  	s->in_handshake++;
  	if (!SSL_in_init(s) || SSL_in_before(s)) SSL_clear(s);
  
  	s->d1->listen = listen;
  #ifndef OPENSSL_NO_SCTP
  	/* Notify SCTP BIO socket to enter handshake
  	 * mode and prevent stream identifier other
  	 * than 0. Will be ignored if no SCTP is used.
  	 */
  	BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_SCTP_SET_IN_HANDSHAKE, s->in_handshake, NULL);
  #endif
  
  	if (s->cert == NULL)
  		{
  		SSLerr(SSL_F_DTLS1_ACCEPT,SSL_R_NO_CERTIFICATE_SET);
  		return(-1);
  		}
  
  #ifndef OPENSSL_NO_HEARTBEATS
  	/* If we're awaiting a HeartbeatResponse, pretend we
  	 * already got and don't await it anymore, because
  	 * Heartbeats don't make sense during handshakes anyway.
  	 */
  	if (s->tlsext_hb_pending)
  		{
  		dtls1_stop_timer(s);
  		s->tlsext_hb_pending = 0;
  		s->tlsext_hb_seq++;
  		}
  #endif
  
  	for (;;)
  		{
  		state=s->state;
  
  		switch (s->state)
  			{
  		case SSL_ST_RENEGOTIATE:
  			s->renegotiate=1;
  			/* s->state=SSL_ST_ACCEPT; */
  
  		case SSL_ST_BEFORE:
  		case SSL_ST_ACCEPT:
  		case SSL_ST_BEFORE|SSL_ST_ACCEPT:
  		case SSL_ST_OK|SSL_ST_ACCEPT:
  
  			s->server=1;
  			if (cb != NULL) cb(s,SSL_CB_HANDSHAKE_START,1);
  
  			if ((s->version & 0xff00) != (DTLS1_VERSION & 0xff00))
  				{
  				SSLerr(SSL_F_DTLS1_ACCEPT, ERR_R_INTERNAL_ERROR);
  				return -1;
  				}
  			s->type=SSL_ST_ACCEPT;
  
  			if (s->init_buf == NULL)
  				{
  				if ((buf=BUF_MEM_new()) == NULL)
  					{
  					ret= -1;
  					goto end;
  					}
  				if (!BUF_MEM_grow(buf,SSL3_RT_MAX_PLAIN_LENGTH))
  					{
  					ret= -1;
  					goto end;
  					}
  				s->init_buf=buf;
  				}
  
  			if (!ssl3_setup_buffers(s))
  				{
  				ret= -1;
  				goto end;
  				}
  
  			s->init_num=0;
  
  			if (s->state != SSL_ST_RENEGOTIATE)
  				{
  				/* Ok, we now need to push on a buffering BIO so that
  				 * the output is sent in a way that TCP likes :-)
  				 * ...but not with SCTP :-)
  				 */
  #ifndef OPENSSL_NO_SCTP
  				if (!BIO_dgram_is_sctp(SSL_get_wbio(s)))
  #endif
  					if (!ssl_init_wbio_buffer(s,1)) { ret= -1; goto end; }
  
  				ssl3_init_finished_mac(s);
  				s->state=SSL3_ST_SR_CLNT_HELLO_A;
  				s->ctx->stats.sess_accept++;
  				}
  			else
  				{
  				/* s->state == SSL_ST_RENEGOTIATE,
  				 * we will just send a HelloRequest */
  				s->ctx->stats.sess_accept_renegotiate++;
  				s->state=SSL3_ST_SW_HELLO_REQ_A;
  				}
  
  			break;
  
  		case SSL3_ST_SW_HELLO_REQ_A:
  		case SSL3_ST_SW_HELLO_REQ_B:
  
  			s->shutdown=0;
  			dtls1_clear_record_buffer(s);
  			dtls1_start_timer(s);
  			ret=ssl3_send_hello_request(s);
  			if (ret <= 0) goto end;
  			s->s3->tmp.next_state=SSL3_ST_SR_CLNT_HELLO_A;
  			s->state=SSL3_ST_SW_FLUSH;
  			s->init_num=0;
  
  			ssl3_init_finished_mac(s);
  			break;
  
  		case SSL3_ST_SW_HELLO_REQ_C:
  			s->state=SSL_ST_OK;
  			break;
  
  		case SSL3_ST_SR_CLNT_HELLO_A:
  		case SSL3_ST_SR_CLNT_HELLO_B:
  		case SSL3_ST_SR_CLNT_HELLO_C:
  
  			s->shutdown=0;
  			ret=ssl3_get_client_hello(s);
  			if (ret <= 0) goto end;
  			dtls1_stop_timer(s);
  
  			if (ret == 1 && (SSL_get_options(s) & SSL_OP_COOKIE_EXCHANGE))
  				s->state = DTLS1_ST_SW_HELLO_VERIFY_REQUEST_A;
  			else
  				s->state = SSL3_ST_SW_SRVR_HELLO_A;
  
  			s->init_num=0;
  
  			/* Reflect ClientHello sequence to remain stateless while listening */
  			if (listen)
  				{
  				memcpy(s->s3->write_sequence, s->s3->read_sequence, sizeof(s->s3->write_sequence));
  				}
  
  			/* If we're just listening, stop here */
  			if (listen && s->state == SSL3_ST_SW_SRVR_HELLO_A)
  				{
  				ret = 2;
  				s->d1->listen = 0;
  				/* Set expected sequence numbers
  				 * to continue the handshake.
  				 */
  				s->d1->handshake_read_seq = 2;
  				s->d1->handshake_write_seq = 1;
  				s->d1->next_handshake_write_seq = 1;
  				goto end;
  				}
  			
  			break;
  			
  		case DTLS1_ST_SW_HELLO_VERIFY_REQUEST_A:
  		case DTLS1_ST_SW_HELLO_VERIFY_REQUEST_B:
  
  			ret = dtls1_send_hello_verify_request(s);
  			if ( ret <= 0) goto end;
  			s->state=SSL3_ST_SW_FLUSH;
  			s->s3->tmp.next_state=SSL3_ST_SR_CLNT_HELLO_A;
  
  			/* HelloVerifyRequest resets Finished MAC */
  			if (s->version != DTLS1_BAD_VER)
  				ssl3_init_finished_mac(s);
  			break;
  			
  #ifndef OPENSSL_NO_SCTP
  		case DTLS1_SCTP_ST_SR_READ_SOCK:
  			
  			if (BIO_dgram_sctp_msg_waiting(SSL_get_rbio(s)))		
  				{
  				s->s3->in_read_app_data=2;
  				s->rwstate=SSL_READING;
  				BIO_clear_retry_flags(SSL_get_rbio(s));
  				BIO_set_retry_read(SSL_get_rbio(s));
  				ret = -1;
  				goto end;
  				}
  			
  			s->state=SSL3_ST_SR_FINISHED_A;
  			break;
  			
  		case DTLS1_SCTP_ST_SW_WRITE_SOCK:
  			ret = BIO_dgram_sctp_wait_for_dry(SSL_get_wbio(s));
  			if (ret < 0) goto end;
  			
  			if (ret == 0)
  				{
  				if (s->d1->next_state != SSL_ST_OK)
  					{
  					s->s3->in_read_app_data=2;
  					s->rwstate=SSL_READING;
  					BIO_clear_retry_flags(SSL_get_rbio(s));
  					BIO_set_retry_read(SSL_get_rbio(s));
  					ret = -1;
  					goto end;
  					}
  				}
  
  			s->state=s->d1->next_state;
  			break;
  #endif
  
  		case SSL3_ST_SW_SRVR_HELLO_A:
  		case SSL3_ST_SW_SRVR_HELLO_B:
  			s->renegotiate = 2;
  			dtls1_start_timer(s);
  			ret=ssl3_send_server_hello(s);
  			if (ret <= 0) goto end;
  
  			if (s->hit)
  				{
  #ifndef OPENSSL_NO_SCTP
  				/* Add new shared key for SCTP-Auth,
  				 * will be ignored if no SCTP used.
  				 */
  				snprintf((char*) labelbuffer, sizeof(DTLS1_SCTP_AUTH_LABEL),
  				         DTLS1_SCTP_AUTH_LABEL);
  
  				SSL_export_keying_material(s, sctpauthkey,
  				                           sizeof(sctpauthkey), labelbuffer,
  				                           sizeof(labelbuffer), NULL, 0, 0);
  				
  				BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_SCTP_ADD_AUTH_KEY,
                           sizeof(sctpauthkey), sctpauthkey);
  #endif
  #ifndef OPENSSL_NO_TLSEXT
  				if (s->tlsext_ticket_expected)
  					s->state=SSL3_ST_SW_SESSION_TICKET_A;
  				else
  					s->state=SSL3_ST_SW_CHANGE_A;
  #else
  				s->state=SSL3_ST_SW_CHANGE_A;
  #endif
  				}
  			else
  				s->state=SSL3_ST_SW_CERT_A;
  			s->init_num=0;
  			break;
  
  		case SSL3_ST_SW_CERT_A:
  		case SSL3_ST_SW_CERT_B:
  			/* Check if it is anon DH or normal PSK */
  			if (!(s->s3->tmp.new_cipher->algorithm_auth & SSL_aNULL)
  				&& !(s->s3->tmp.new_cipher->algorithm_mkey & SSL_kPSK))
  				{
  				dtls1_start_timer(s);
  				ret=ssl3_send_server_certificate(s);
  				if (ret <= 0) goto end;
  #ifndef OPENSSL_NO_TLSEXT
  				if (s->tlsext_status_expected)
  					s->state=SSL3_ST_SW_CERT_STATUS_A;
  				else
  					s->state=SSL3_ST_SW_KEY_EXCH_A;
  				}
  			else
  				{
  				skip = 1;
  				s->state=SSL3_ST_SW_KEY_EXCH_A;
  				}
  #else
  				}
  			else
  				skip=1;
  
  			s->state=SSL3_ST_SW_KEY_EXCH_A;
  #endif
  			s->init_num=0;
  			break;
  
  		case SSL3_ST_SW_KEY_EXCH_A:
  		case SSL3_ST_SW_KEY_EXCH_B:
  			alg_k = s->s3->tmp.new_cipher->algorithm_mkey;
  
  			/* clear this, it may get reset by
  			 * send_server_key_exchange */
  			if ((s->options & SSL_OP_EPHEMERAL_RSA)
  #ifndef OPENSSL_NO_KRB5
  				&& !(alg_k & SSL_kKRB5)
  #endif /* OPENSSL_NO_KRB5 */
  				)
  				/* option SSL_OP_EPHEMERAL_RSA sends temporary RSA key
  				 * even when forbidden by protocol specs
  				 * (handshake may fail as clients are not required to
  				 * be able to handle this) */
  				s->s3->tmp.use_rsa_tmp=1;
  			else
  				s->s3->tmp.use_rsa_tmp=0;
  
  			/* only send if a DH key exchange or
  			 * RSA but we have a sign only certificate */
  			if (s->s3->tmp.use_rsa_tmp
  			/* PSK: send ServerKeyExchange if PSK identity
  			 * hint if provided */
  #ifndef OPENSSL_NO_PSK
  			    || ((alg_k & SSL_kPSK) && s->ctx->psk_identity_hint)
  #endif
  			    || (alg_k & (SSL_kDHE|SSL_kDHr|SSL_kDHd))
  			    || (alg_k & SSL_kECDHE)
  			    || ((alg_k & SSL_kRSA)
  				&& (s->cert->pkeys[SSL_PKEY_RSA_ENC].privatekey == NULL
  				    || (SSL_C_IS_EXPORT(s->s3->tmp.new_cipher)
  					&& EVP_PKEY_size(s->cert->pkeys[SSL_PKEY_RSA_ENC].privatekey)*8 > SSL_C_EXPORT_PKEYLENGTH(s->s3->tmp.new_cipher)
  					)
  				    )
  				)
  			    )
  				{
  				dtls1_start_timer(s);
  				ret=ssl3_send_server_key_exchange(s);
  				if (ret <= 0) goto end;
  				}
  			else
  				skip=1;
  
  			s->state=SSL3_ST_SW_CERT_REQ_A;
  			s->init_num=0;
  			break;
  
  		case SSL3_ST_SW_CERT_REQ_A:
  		case SSL3_ST_SW_CERT_REQ_B:
  			if (/* don't request cert unless asked for it: */
  				!(s->verify_mode & SSL_VERIFY_PEER) ||
  				/* if SSL_VERIFY_CLIENT_ONCE is set,
  				 * don't request cert during re-negotiation: */
  				((s->session->peer != NULL) &&
  				 (s->verify_mode & SSL_VERIFY_CLIENT_ONCE)) ||
  				/* never request cert in anonymous ciphersuites
  				 * (see section "Certificate request" in SSL 3 drafts
  				 * and in RFC 2246): */
  				((s->s3->tmp.new_cipher->algorithm_auth & SSL_aNULL) &&
  				 /* ... except when the application insists on verification
  				  * (against the specs, but s3_clnt.c accepts this for SSL 3) */
  				 !(s->verify_mode & SSL_VERIFY_FAIL_IF_NO_PEER_CERT)) ||
  				 /* never request cert in Kerberos ciphersuites */
  				(s->s3->tmp.new_cipher->algorithm_auth & SSL_aKRB5)
  				/* With normal PSK Certificates and
  				 * Certificate Requests are omitted */
  				|| (s->s3->tmp.new_cipher->algorithm_mkey & SSL_kPSK))
  				{
  				/* no cert request */
  				skip=1;
  				s->s3->tmp.cert_request=0;
  				s->state=SSL3_ST_SW_SRVR_DONE_A;
  #ifndef OPENSSL_NO_SCTP
  				if (BIO_dgram_is_sctp(SSL_get_wbio(s)))
  					{
  					s->d1->next_state = SSL3_ST_SW_SRVR_DONE_A;
  					s->state = DTLS1_SCTP_ST_SW_WRITE_SOCK;
  					}
  #endif
  				}
  			else
  				{
  				s->s3->tmp.cert_request=1;
  				dtls1_start_timer(s);
  				ret=ssl3_send_certificate_request(s);
  				if (ret <= 0) goto end;
  #ifndef NETSCAPE_HANG_BUG
  				s->state=SSL3_ST_SW_SRVR_DONE_A;
  #ifndef OPENSSL_NO_SCTP
  				if (BIO_dgram_is_sctp(SSL_get_wbio(s)))
  					{
  					s->d1->next_state = SSL3_ST_SW_SRVR_DONE_A;
  					s->state = DTLS1_SCTP_ST_SW_WRITE_SOCK;
  					}
  #endif
  #else
  				s->state=SSL3_ST_SW_FLUSH;
  				s->s3->tmp.next_state=SSL3_ST_SR_CERT_A;
  #ifndef OPENSSL_NO_SCTP
  				if (BIO_dgram_is_sctp(SSL_get_wbio(s)))
  					{
  					s->d1->next_state = s->s3->tmp.next_state;
  					s->s3->tmp.next_state=DTLS1_SCTP_ST_SW_WRITE_SOCK;
  					}
  #endif
  #endif
  				s->init_num=0;
  				}
  			break;
  
  		case SSL3_ST_SW_SRVR_DONE_A:
  		case SSL3_ST_SW_SRVR_DONE_B:
  			dtls1_start_timer(s);
  			ret=ssl3_send_server_done(s);
  			if (ret <= 0) goto end;
  			s->s3->tmp.next_state=SSL3_ST_SR_CERT_A;
  			s->state=SSL3_ST_SW_FLUSH;
  			s->init_num=0;
  			break;
  		
  		case SSL3_ST_SW_FLUSH:
  			s->rwstate=SSL_WRITING;
  			if (BIO_flush(s->wbio) <= 0)
  				{
  				/* If the write error was fatal, stop trying */
  				if (!BIO_should_retry(s->wbio))
  					{
  					s->rwstate=SSL_NOTHING;
  					s->state=s->s3->tmp.next_state;
  					}
  				
  				ret= -1;
  				goto end;
  				}
  			s->rwstate=SSL_NOTHING;
  			s->state=s->s3->tmp.next_state;
  			break;
  
  		case SSL3_ST_SR_CERT_A:
  		case SSL3_ST_SR_CERT_B:
  			/* Check for second client hello (MS SGC) */
  			ret = ssl3_check_client_hello(s);
  			if (ret <= 0)
  				goto end;
  			if (ret == 2)
  				{
  				dtls1_stop_timer(s);
  				s->state = SSL3_ST_SR_CLNT_HELLO_C;
  				}
  			else {
  				/* could be sent for a DH cert, even if we
  				 * have not asked for it :-) */
  				ret=ssl3_get_client_certificate(s);
  				if (ret <= 0) goto end;
  				s->init_num=0;
  				s->state=SSL3_ST_SR_KEY_EXCH_A;
  			}
  			break;
  
  		case SSL3_ST_SR_KEY_EXCH_A:
  		case SSL3_ST_SR_KEY_EXCH_B:
  			ret=ssl3_get_client_key_exchange(s);
  			if (ret <= 0) goto end;
  #ifndef OPENSSL_NO_SCTP
  			/* Add new shared key for SCTP-Auth,
  			 * will be ignored if no SCTP used.
  			 */
  			snprintf((char *) labelbuffer, sizeof(DTLS1_SCTP_AUTH_LABEL),
  			         DTLS1_SCTP_AUTH_LABEL);
  
  			SSL_export_keying_material(s, sctpauthkey,
  			                           sizeof(sctpauthkey), labelbuffer,
  			                           sizeof(labelbuffer), NULL, 0, 0);
  
  			BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_SCTP_ADD_AUTH_KEY,
  			         sizeof(sctpauthkey), sctpauthkey);
  #endif
  
  			s->state=SSL3_ST_SR_CERT_VRFY_A;
  			s->init_num=0;
  
  			if (ret == 2)
  				{
  				/* For the ECDH ciphersuites when
  				 * the client sends its ECDH pub key in
  				 * a certificate, the CertificateVerify
  				 * message is not sent.
  				 */
  				s->state=SSL3_ST_SR_FINISHED_A;
  				s->init_num = 0;
  				}
  			else if (SSL_USE_SIGALGS(s))
  				{
  				s->state=SSL3_ST_SR_CERT_VRFY_A;
  				s->init_num=0;
  				if (!s->session->peer)
  					break;
  				/* For sigalgs freeze the handshake buffer
  				 * at this point and digest cached records.
  				 */
  				if (!s->s3->handshake_buffer)
  					{
  					SSLerr(SSL_F_DTLS1_ACCEPT,ERR_R_INTERNAL_ERROR);
  					return -1;
  					}
  				s->s3->flags |= TLS1_FLAGS_KEEP_HANDSHAKE;
  				if (!ssl3_digest_cached_records(s))
  					return -1;
  				}
  			else
  				{
  				s->state=SSL3_ST_SR_CERT_VRFY_A;
  				s->init_num=0;
  
  				/* We need to get hashes here so if there is
  				 * a client cert, it can be verified */ 
  				s->method->ssl3_enc->cert_verify_mac(s,
  					NID_md5,
  					&(s->s3->tmp.cert_verify_md[0]));
  				s->method->ssl3_enc->cert_verify_mac(s,
  					NID_sha1,
  					&(s->s3->tmp.cert_verify_md[MD5_DIGEST_LENGTH]));
  				}
  			break;
  
  		case SSL3_ST_SR_CERT_VRFY_A:
  		case SSL3_ST_SR_CERT_VRFY_B:
  
  			s->d1->change_cipher_spec_ok = 1;
  			/* we should decide if we expected this one */
  			ret=ssl3_get_cert_verify(s);
  			if (ret <= 0) goto end;
  #ifndef OPENSSL_NO_SCTP
  			if (BIO_dgram_is_sctp(SSL_get_wbio(s)) &&
  			    state == SSL_ST_RENEGOTIATE)
  				s->state=DTLS1_SCTP_ST_SR_READ_SOCK;
  			else
  #endif			
  				s->state=SSL3_ST_SR_FINISHED_A;
  			s->init_num=0;
  			break;
  
  		case SSL3_ST_SR_FINISHED_A:
  		case SSL3_ST_SR_FINISHED_B:
  			s->d1->change_cipher_spec_ok = 1;
  			ret=ssl3_get_finished(s,SSL3_ST_SR_FINISHED_A,
  				SSL3_ST_SR_FINISHED_B);
  			if (ret <= 0) goto end;
  			dtls1_stop_timer(s);
  			if (s->hit)
  				s->state=SSL_ST_OK;
  #ifndef OPENSSL_NO_TLSEXT
  			else if (s->tlsext_ticket_expected)
  				s->state=SSL3_ST_SW_SESSION_TICKET_A;
  #endif
  			else
  				s->state=SSL3_ST_SW_CHANGE_A;
  			s->init_num=0;
  			break;
  
  #ifndef OPENSSL_NO_TLSEXT
  		case SSL3_ST_SW_SESSION_TICKET_A:
  		case SSL3_ST_SW_SESSION_TICKET_B:
  			ret=ssl3_send_newsession_ticket(s);
  			if (ret <= 0) goto end;
  			s->state=SSL3_ST_SW_CHANGE_A;
  			s->init_num=0;
  			break;
  
  		case SSL3_ST_SW_CERT_STATUS_A:
  		case SSL3_ST_SW_CERT_STATUS_B:
  			ret=ssl3_send_cert_status(s);
  			if (ret <= 0) goto end;
  			s->state=SSL3_ST_SW_KEY_EXCH_A;
  			s->init_num=0;
  			break;
  
  #endif
  
  		case SSL3_ST_SW_CHANGE_A:
  		case SSL3_ST_SW_CHANGE_B:
  
  			s->session->cipher=s->s3->tmp.new_cipher;
  			if (!s->method->ssl3_enc->setup_key_block(s))
  				{ ret= -1; goto end; }
  
  			ret=dtls1_send_change_cipher_spec(s,
  				SSL3_ST_SW_CHANGE_A,SSL3_ST_SW_CHANGE_B);
  
  			if (ret <= 0) goto end;
  
  #ifndef OPENSSL_NO_SCTP
  			if (!s->hit)
  				{
  				/* Change to new shared key of SCTP-Auth,
  				 * will be ignored if no SCTP used.
  				 */
  				BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_SCTP_NEXT_AUTH_KEY, 0, NULL);
  				}
  #endif
  
  			s->state=SSL3_ST_SW_FINISHED_A;
  			s->init_num=0;
  
  			if (!s->method->ssl3_enc->change_cipher_state(s,
  				SSL3_CHANGE_CIPHER_SERVER_WRITE))
  				{
  				ret= -1;
  				goto end;
  				}
  
  			dtls1_reset_seq_numbers(s, SSL3_CC_WRITE);
  			break;
  
  		case SSL3_ST_SW_FINISHED_A:
  		case SSL3_ST_SW_FINISHED_B:
  			ret=ssl3_send_finished(s,
  				SSL3_ST_SW_FINISHED_A,SSL3_ST_SW_FINISHED_B,
  				s->method->ssl3_enc->server_finished_label,
  				s->method->ssl3_enc->server_finished_label_len);
  			if (ret <= 0) goto end;
  			s->state=SSL3_ST_SW_FLUSH;
  			if (s->hit)
  				{
  				s->s3->tmp.next_state=SSL3_ST_SR_FINISHED_A;
  
  #ifndef OPENSSL_NO_SCTP
  				/* Change to new shared key of SCTP-Auth,
  				 * will be ignored if no SCTP used.
  				 */
  				BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_SCTP_NEXT_AUTH_KEY, 0, NULL);
  #endif
  				}
  			else
  				{
  				s->s3->tmp.next_state=SSL_ST_OK;
  #ifndef OPENSSL_NO_SCTP
  				if (BIO_dgram_is_sctp(SSL_get_wbio(s)))
  					{
  					s->d1->next_state = s->s3->tmp.next_state;
  					s->s3->tmp.next_state=DTLS1_SCTP_ST_SW_WRITE_SOCK;
  					}
  #endif
  				}
  			s->init_num=0;
  			break;
  
  		case SSL_ST_OK:
  			/* clean a few things up */
  			ssl3_cleanup_key_block(s);
  
  #if 0
  			BUF_MEM_free(s->init_buf);
  			s->init_buf=NULL;
  #endif
  
  			/* remove buffering on output */
  			ssl_free_wbio_buffer(s);
  
  			s->init_num=0;
  
  			if (s->renegotiate == 2) /* skipped if we just sent a HelloRequest */
  				{
  				s->renegotiate=0;
  				s->new_session=0;
  				
  				ssl_update_cache(s,SSL_SESS_CACHE_SERVER);
  				
  				s->ctx->stats.sess_accept_good++;
  				/* s->server=1; */
  				s->handshake_func=dtls1_accept;
  
  				if (cb != NULL) cb(s,SSL_CB_HANDSHAKE_DONE,1);
  				}
  			
  			ret = 1;
  
  			/* done handshaking, next message is client hello */
  			s->d1->handshake_read_seq = 0;
  			/* next message is server hello */
  			s->d1->handshake_write_seq = 0;
  			s->d1->next_handshake_write_seq = 0;
  			goto end;
  			/* break; */
  
  		default:
  			SSLerr(SSL_F_DTLS1_ACCEPT,SSL_R_UNKNOWN_STATE);
  			ret= -1;
  			goto end;
  			/* break; */
  			}
  		
  		if (!s->s3->tmp.reuse_message && !skip)
  			{
  			if (s->debug)
  				{
  				if ((ret=BIO_flush(s->wbio)) <= 0)
  					goto end;
  				}
  
  
  			if ((cb != NULL) && (s->state != state))
  				{
  				new_state=s->state;
  				s->state=state;
  				cb(s,SSL_CB_ACCEPT_LOOP,1);
  				s->state=new_state;
  				}
  			}
  		skip=0;
  		}
  end:
  	/* BIO_flush(s->wbio); */
  
  	s->in_handshake--;
  #ifndef OPENSSL_NO_SCTP
  		/* Notify SCTP BIO socket to leave handshake
  		 * mode and prevent stream identifier other
  		 * than 0. Will be ignored if no SCTP is used.
  		 */
  		BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_SCTP_SET_IN_HANDSHAKE, s->in_handshake, NULL);
  #endif
  
  	if (cb != NULL)
  		cb(s,SSL_CB_ACCEPT_EXIT,ret);
  	return(ret);
  	}
  
  int dtls1_send_hello_verify_request(SSL *s)
  	{
  	unsigned int msg_len;
  	unsigned char *msg, *buf, *p;
  
  	if (s->state == DTLS1_ST_SW_HELLO_VERIFY_REQUEST_A)
  		{
  		buf = (unsigned char *)s->init_buf->data;
  
  		msg = p = &(buf[DTLS1_HM_HEADER_LENGTH]);
  		/* Always use DTLS 1.0 version: see RFC 6347 */
  		*(p++) = DTLS1_VERSION >> 8;
  		*(p++) = DTLS1_VERSION & 0xFF;
  
  		if (s->ctx->app_gen_cookie_cb == NULL ||
  		     s->ctx->app_gen_cookie_cb(s, s->d1->cookie,
  			 &(s->d1->cookie_len)) == 0)
  			{
  			SSLerr(SSL_F_DTLS1_SEND_HELLO_VERIFY_REQUEST,ERR_R_INTERNAL_ERROR);
  			return 0;
  			}
  
  		*(p++) = (unsigned char) s->d1->cookie_len;
  		memcpy(p, s->d1->cookie, s->d1->cookie_len);
  		p += s->d1->cookie_len;
  		msg_len = p - msg;
  
  		dtls1_set_message_header(s, buf,
  			DTLS1_MT_HELLO_VERIFY_REQUEST, msg_len, 0, msg_len);
  
  		s->state=DTLS1_ST_SW_HELLO_VERIFY_REQUEST_B;
  		/* number of bytes to write */
  		s->init_num=p-buf;
  		s->init_off=0;
  		}
  
  	/* s->state = DTLS1_ST_SW_HELLO_VERIFY_REQUEST_B */
  	return(dtls1_do_write(s,SSL3_RT_HANDSHAKE));
  	}
  