d1_srvr.c

/* 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>
#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
		return(NULL);
	}

IMPLEMENT_dtls1_meth_func(DTLSv1_server_method,
			dtls1_accept,
			ssl_undefined_function,
			dtls1_get_server_method)

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;
	long num1;
	unsigned long alg_k;
	int ret= -1;
	int new_state,state,skip=0;

	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;

	/* init things to blank */
	s->in_handshake++;
	if (!SSL_in_init(s) || SSL_in_before(s)) SSL_clear(s);

	if (s->cert == NULL)
		{
		SSLerr(SSL_F_DTLS1_ACCEPT,SSL_R_NO_CERTIFICATE_SET);
		return(-1);
		}

	for (;;)
		{
		state=s->state;

		switch (s->state)
			{
		case SSL_ST_RENEGOTIATE:
			s->new_session=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 :-)
				 */
				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;
				}

			if ( (SSL_get_options(s) & SSL_OP_COOKIE_EXCHANGE))
				s->d1->send_cookie = 1;
			else
				s->d1->send_cookie = 0;
			
			break;

		case SSL3_ST_SW_HELLO_REQ_A:
		case SSL3_ST_SW_HELLO_REQ_B:

			s->shutdown=0;
			ret=dtls1_send_hello_request(s);
			if (ret <= 0) goto end;
			s->s3->tmp.next_state=SSL3_ST_SW_HELLO_REQ_C;
			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;
			s->new_session = 2;

			if (s->d1->send_cookie)
				s->state = DTLS1_ST_SW_HELLO_VERIFY_REQUEST_A;
			else
				s->state = SSL3_ST_SW_SRVR_HELLO_A;

			s->init_num=0;
			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->d1->send_cookie = 0;
			s->state=SSL3_ST_SW_FLUSH;
			s->s3->tmp.next_state=SSL3_ST_SR_CLNT_HELLO_A;
			break;
			
		case SSL3_ST_SW_SRVR_HELLO_A:
		case SSL3_ST_SW_SRVR_HELLO_B:
			ret=dtls1_send_server_hello(s);
			if (ret <= 0) goto end;

			if (s->hit)
				s->state=SSL3_ST_SW_CHANGE_A;
			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 */
			if (!(s->s3->tmp.new_cipher->algorithm_auth & SSL_aNULL))
				{
				ret=dtls1_send_server_certificate(s);
				if (ret <= 0) goto end;
				}
			else
				skip=1;
			s->state=SSL3_ST_SW_KEY_EXCH_A;
			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
			    || (alg_k & (SSL_kEDH|SSL_kDHr|SSL_kDHd))
			    || ((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)
					)
				    )
				)
			    )
				{
				ret=dtls1_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))
				{
				/* no cert request */
				skip=1;
				s->s3->tmp.cert_request=0;
				s->state=SSL3_ST_SW_SRVR_DONE_A;
				}
			else
				{
				s->s3->tmp.cert_request=1;
				ret=dtls1_send_certificate_request(s);
				if (ret <= 0) goto end;
#ifndef NETSCAPE_HANG_BUG
				s->state=SSL3_ST_SW_SRVR_DONE_A;
#else
				s->state=SSL3_ST_SW_FLUSH;
				s->s3->tmp.next_state=SSL3_ST_SR_CERT_A;
#endif
				s->init_num=0;
				}
			break;

		case SSL3_ST_SW_SRVR_DONE_A:
		case SSL3_ST_SW_SRVR_DONE_B:
			ret=dtls1_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:
			/* number of bytes to be flushed */
			num1=BIO_ctrl(s->wbio,BIO_CTRL_INFO,0,NULL);
			if (num1 > 0)
				{
				s->rwstate=SSL_WRITING;
				num1=BIO_flush(s->wbio);
				if (num1 <= 0) { 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)
				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;
			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:

			/* we should decide if we expected this one */
			ret=ssl3_get_cert_verify(s);
			if (ret <= 0) goto end;

			s->state=SSL3_ST_SR_FINISHED_A;
			s->init_num=0;
			break;

		case SSL3_ST_SR_FINISHED_A:
		case SSL3_ST_SR_FINISHED_B:
			ret=ssl3_get_finished(s,SSL3_ST_SR_FINISHED_A,
				SSL3_ST_SR_FINISHED_B);
			if (ret <= 0) goto end;
			if (s->hit)
				s->state=SSL_ST_OK;
			else
				s->state=SSL3_ST_SW_CHANGE_A;
			s->init_num=0;
			break;

		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;
			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=dtls1_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;
			else
				s->s3->tmp.next_state=SSL_ST_OK;
			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->new_session == 2) /* skipped if we just sent a HelloRequest */
				{
				/* actually not necessarily a 'new' session unless
				 * SSL_OP_NO_SESSION_RESUMPTION_ON_RENEGOTIATION is set */
				
				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;
			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--;
	if (cb != NULL)
		cb(s,SSL_CB_ACCEPT_EXIT,ret);
	return(ret);
	}

int dtls1_send_hello_request(SSL *s)
	{
	unsigned char *p;

	if (s->state == SSL3_ST_SW_HELLO_REQ_A)
		{
		p=(unsigned char *)s->init_buf->data;
		p = dtls1_set_message_header(s, p, SSL3_MT_HELLO_REQUEST, 0, 0, 0);

		s->state=SSL3_ST_SW_HELLO_REQ_B;
		/* number of bytes to write */
		s->init_num=DTLS1_HM_HEADER_LENGTH;
		s->init_off=0;

		/* no need to buffer this message, since there are no retransmit 
		 * requests for it */
		}

	/* SSL3_ST_SW_HELLO_REQ_B */
	return(dtls1_do_write(s,SSL3_RT_HANDSHAKE));
	}

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]);
		*(p++) = s->version >> 8;
		*(p++) = s->version & 0xFF;

		*(p++) = (unsigned char) s->d1->cookie_len;

		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;
			}
		/* else the cookie is assumed to have 
		 * been initialized by the application */

		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;

		/* buffer the message to handle re-xmits */
		dtls1_buffer_message(s, 0);
		}

	/* s->state = DTLS1_ST_SW_HELLO_VERIFY_REQUEST_B */
	return(dtls1_do_write(s,SSL3_RT_HANDSHAKE));
	}

int dtls1_send_server_hello(SSL *s)
	{
	unsigned char *buf;
	unsigned char *p,*d;
	int i;
	unsigned int sl;
	unsigned long l,Time;

	if (s->state == SSL3_ST_SW_SRVR_HELLO_A)
		{
		buf=(unsigned char *)s->init_buf->data;
		p=s->s3->server_random;
		Time=(unsigned long)time(NULL);			/* Time */
		l2n(Time,p);
		RAND_pseudo_bytes(p,SSL3_RANDOM_SIZE-sizeof(Time));
		/* Do the message type and length last */
		d=p= &(buf[DTLS1_HM_HEADER_LENGTH]);

		*(p++)=s->version>>8;
		*(p++)=s->version&0xff;

		/* Random stuff */
		memcpy(p,s->s3->server_random,SSL3_RANDOM_SIZE);
		p+=SSL3_RANDOM_SIZE;

		/* now in theory we have 3 options to sending back the
		 * session id.  If it is a re-use, we send back the
		 * old session-id, if it is a new session, we send
		 * back the new session-id or we send back a 0 length
		 * session-id if we want it to be single use.
		 * Currently I will not implement the '0' length session-id
		 * 12-Jan-98 - I'll now support the '0' length stuff.
		 */
		if (!(s->ctx->session_cache_mode & SSL_SESS_CACHE_SERVER))
			s->session->session_id_length=0;

		sl=s->session->session_id_length;
		if (sl > sizeof s->session->session_id)
			{
			SSLerr(SSL_F_DTLS1_SEND_SERVER_HELLO, ERR_R_INTERNAL_ERROR);
			return -1;
			}
		*(p++)=sl;
		memcpy(p,s->session->session_id,sl);
		p+=sl;

		/* put the cipher */
		i=ssl3_put_cipher_by_char(s->s3->tmp.new_cipher,p);
		p+=i;

		/* put the compression method */
#ifdef OPENSSL_NO_COMP
		*(p++)=0;
#else
		if (s->s3->tmp.new_compression == NULL)
			*(p++)=0;
		else
			*(p++)=s->s3->tmp.new_compression->id;
#endif

		/* do the header */
		l=(p-d);
		d=buf;

		d = dtls1_set_message_header(s, d, SSL3_MT_SERVER_HELLO, l, 0, l);

		s->state=SSL3_ST_CW_CLNT_HELLO_B;
		/* number of bytes to write */
		s->init_num=p-buf;
		s->init_off=0;

		/* buffer the message to handle re-xmits */
		dtls1_buffer_message(s, 0);
		}

	/* SSL3_ST_CW_CLNT_HELLO_B */
	return(dtls1_do_write(s,SSL3_RT_HANDSHAKE));
	}

int dtls1_send_server_done(SSL *s)
	{
	unsigned char *p;

	if (s->state == SSL3_ST_SW_SRVR_DONE_A)
		{
		p=(unsigned char *)s->init_buf->data;

		/* do the header */
		p = dtls1_set_message_header(s, p, SSL3_MT_SERVER_DONE, 0, 0, 0);

		s->state=SSL3_ST_SW_SRVR_DONE_B;
		/* number of bytes to write */
		s->init_num=DTLS1_HM_HEADER_LENGTH;
		s->init_off=0;

		/* buffer the message to handle re-xmits */
		dtls1_buffer_message(s, 0);
		}

	/* SSL3_ST_CW_CLNT_HELLO_B */
	return(dtls1_do_write(s,SSL3_RT_HANDSHAKE));
	}

int dtls1_send_server_key_exchange(SSL *s)
	{
#ifndef OPENSSL_NO_RSA
	unsigned char *q;
	int j,num;
	RSA *rsa;
	unsigned char md_buf[MD5_DIGEST_LENGTH+SHA_DIGEST_LENGTH];
	unsigned int u;
#endif
#ifndef OPENSSL_NO_DH
	DH *dh=NULL,*dhp;
#endif
	EVP_PKEY *pkey;
	unsigned char *p,*d;
	int al,i;
	unsigned long type;
	int n;
	CERT *cert;
	BIGNUM *r[4];
	int nr[4],kn;
	BUF_MEM *buf;
	EVP_MD_CTX md_ctx;

	EVP_MD_CTX_init(&md_ctx);
	if (s->state == SSL3_ST_SW_KEY_EXCH_A)
		{
		type=s->s3->tmp.new_cipher->algorithm_mkey;
		cert=s->cert;

		buf=s->init_buf;

		r[0]=r[1]=r[2]=r[3]=NULL;
		n=0;
#ifndef OPENSSL_NO_RSA
		if (type & SSL_kRSA)
			{
			rsa=cert->rsa_tmp;
			if ((rsa == NULL) && (s->cert->rsa_tmp_cb != NULL))
				{
				rsa=s->cert->rsa_tmp_cb(s,
				      SSL_C_IS_EXPORT(s->s3->tmp.new_cipher),
				      SSL_C_EXPORT_PKEYLENGTH(s->s3->tmp.new_cipher));
				if(rsa == NULL)
				{
					al=SSL_AD_HANDSHAKE_FAILURE;
					SSLerr(SSL_F_DTLS1_SEND_SERVER_KEY_EXCHANGE,SSL_R_ERROR_GENERATING_TMP_RSA_KEY);
					goto f_err;
				}
				RSA_up_ref(rsa);
				cert->rsa_tmp=rsa;
				}
			if (rsa == NULL)
				{
				al=SSL_AD_HANDSHAKE_FAILURE;
				SSLerr(SSL_F_DTLS1_SEND_SERVER_KEY_EXCHANGE,SSL_R_MISSING_TMP_RSA_KEY);
				goto f_err;
				}
			r[0]=rsa->n;
			r[1]=rsa->e;
			s->s3->tmp.use_rsa_tmp=1;
			}
		else
#endif
#ifndef OPENSSL_NO_DH
			if (type & SSL_kEDH)
			{
			dhp=cert->dh_tmp;
			if ((dhp == NULL) && (s->cert->dh_tmp_cb != NULL))
				dhp=s->cert->dh_tmp_cb(s,
				      SSL_C_IS_EXPORT(s->s3->tmp.new_cipher),
				      SSL_C_EXPORT_PKEYLENGTH(s->s3->tmp.new_cipher));
			if (dhp == NULL)
				{
				al=SSL_AD_HANDSHAKE_FAILURE;
				SSLerr(SSL_F_DTLS1_SEND_SERVER_KEY_EXCHANGE,SSL_R_MISSING_TMP_DH_KEY);
				goto f_err;
				}

			if (s->s3->tmp.dh != NULL)
				{
				DH_free(dh);
				SSLerr(SSL_F_DTLS1_SEND_SERVER_KEY_EXCHANGE, ERR_R_INTERNAL_ERROR);
				goto err;
				}

			if ((dh=DHparams_dup(dhp)) == NULL)
				{
				SSLerr(SSL_F_DTLS1_SEND_SERVER_KEY_EXCHANGE,ERR_R_DH_LIB);
				goto err;
				}

			s->s3->tmp.dh=dh;
			if ((dhp->pub_key == NULL ||
			     dhp->priv_key == NULL ||
			     (s->options & SSL_OP_SINGLE_DH_USE)))
				{
				if(!DH_generate_key(dh))
				    {
				    SSLerr(SSL_F_DTLS1_SEND_SERVER_KEY_EXCHANGE,
					   ERR_R_DH_LIB);
				    goto err;
				    }
				}
			else
				{
				dh->pub_key=BN_dup(dhp->pub_key);
				dh->priv_key=BN_dup(dhp->priv_key);
				if ((dh->pub_key == NULL) ||
					(dh->priv_key == NULL))
					{
					SSLerr(SSL_F_DTLS1_SEND_SERVER_KEY_EXCHANGE,ERR_R_DH_LIB);
					goto err;
					}
				}
			r[0]=dh->p;
			r[1]=dh->g;
			r[2]=dh->pub_key;
			}
		else 
#endif
			{
			al=SSL_AD_HANDSHAKE_FAILURE;
			SSLerr(SSL_F_DTLS1_SEND_SERVER_KEY_EXCHANGE,SSL_R_UNKNOWN_KEY_EXCHANGE_TYPE);
			goto f_err;
			}
		for (i=0; r[i] != NULL; i++)
			{
			nr[i]=BN_num_bytes(r[i]);
			n+=2+nr[i];
			}

		if (!(s->s3->tmp.new_cipher->algorithm_auth & SSL_aNULL))
			{
			if ((pkey=ssl_get_sign_pkey(s,s->s3->tmp.new_cipher))
				== NULL)
				{
				al=SSL_AD_DECODE_ERROR;
				goto f_err;
				}
			kn=EVP_PKEY_size(pkey);
			}
		else
			{
			pkey=NULL;
			kn=0;
			}

		if (!BUF_MEM_grow_clean(buf,n+DTLS1_HM_HEADER_LENGTH+kn))
			{
			SSLerr(SSL_F_DTLS1_SEND_SERVER_KEY_EXCHANGE,ERR_LIB_BUF);
			goto err;
			}
		d=(unsigned char *)s->init_buf->data;
		p= &(d[DTLS1_HM_HEADER_LENGTH]);

		for (i=0; r[i] != NULL; i++)
			{
			s2n(nr[i],p);
			BN_bn2bin(r[i],p);
			p+=nr[i];
			}

		/* not anonymous */
		if (pkey != NULL)
			{
			/* n is the length of the params, they start at
			 * &(d[DTLS1_HM_HEADER_LENGTH]) and p points to the space
			 * at the end. */
#ifndef OPENSSL_NO_RSA
			if (pkey->type == EVP_PKEY_RSA)
				{
				q=md_buf;
				j=0;
				for (num=2; num > 0; num--)
					{
					EVP_DigestInit_ex(&md_ctx,(num == 2)
						?s->ctx->md5:s->ctx->sha1, NULL);
					EVP_DigestUpdate(&md_ctx,&(s->s3->client_random[0]),SSL3_RANDOM_SIZE);
					EVP_DigestUpdate(&md_ctx,&(s->s3->server_random[0]),SSL3_RANDOM_SIZE);
					EVP_DigestUpdate(&md_ctx,&(d[DTLS1_HM_HEADER_LENGTH]),n);
					EVP_DigestFinal_ex(&md_ctx,q,
						(unsigned int *)&i);
					q+=i;
					j+=i;
					}
				if (RSA_sign(NID_md5_sha1, md_buf, j,
					&(p[2]), &u, pkey->pkey.rsa) <= 0)
					{
					SSLerr(SSL_F_DTLS1_SEND_SERVER_KEY_EXCHANGE,ERR_LIB_RSA);
					goto err;
					}
				s2n(u,p);
				n+=u+2;
				}
			else
#endif
#if !defined(OPENSSL_NO_DSA)
				if (pkey->type == EVP_PKEY_DSA)
				{
				/* lets do DSS */
				EVP_SignInit_ex(&md_ctx,EVP_dss1(), NULL);
				EVP_SignUpdate(&md_ctx,&(s->s3->client_random[0]),SSL3_RANDOM_SIZE);
				EVP_SignUpdate(&md_ctx,&(s->s3->server_random[0]),SSL3_RANDOM_SIZE);
				EVP_SignUpdate(&md_ctx,&(d[DTLS1_HM_HEADER_LENGTH]),n);
				if (!EVP_SignFinal(&md_ctx,&(p[2]),
					(unsigned int *)&i,pkey))
					{
					SSLerr(SSL_F_DTLS1_SEND_SERVER_KEY_EXCHANGE,ERR_LIB_DSA);
					goto err;
					}
				s2n(i,p);
				n+=i+2;
				}
			else
#endif
				{
				/* Is this error check actually needed? */
				al=SSL_AD_HANDSHAKE_FAILURE;
				SSLerr(SSL_F_DTLS1_SEND_SERVER_KEY_EXCHANGE,SSL_R_UNKNOWN_PKEY_TYPE);
				goto f_err;
				}
			}

		d = dtls1_set_message_header(s, d,
			SSL3_MT_SERVER_KEY_EXCHANGE, n, 0, n);

		/* we should now have things packed up, so lets send
		 * it off */
		s->init_num=n+DTLS1_HM_HEADER_LENGTH;
		s->init_off=0;

		/* buffer the message to handle re-xmits */
		dtls1_buffer_message(s, 0);
		}

	s->state = SSL3_ST_SW_KEY_EXCH_B;
	EVP_MD_CTX_cleanup(&md_ctx);
	return(dtls1_do_write(s,SSL3_RT_HANDSHAKE));
f_err:
	ssl3_send_alert(s,SSL3_AL_FATAL,al);
err:
	EVP_MD_CTX_cleanup(&md_ctx);
	return(-1);
	}

int dtls1_send_certificate_request(SSL *s)
	{
	unsigned char *p,*d;
	int i,j,nl,off,n;
	STACK_OF(X509_NAME) *sk=NULL;
	X509_NAME *name;
	BUF_MEM *buf;
	unsigned int msg_len;

	if (s->state == SSL3_ST_SW_CERT_REQ_A)
		{
		buf=s->init_buf;

		d=p=(unsigned char *)&(buf->data[DTLS1_HM_HEADER_LENGTH]);

		/* get the list of acceptable cert types */
		p++;
		n=ssl3_get_req_cert_type(s,p);
		d[0]=n;
		p+=n;
		n++;

		off=n;
		p+=2;
		n+=2;

		sk=SSL_get_client_CA_list(s);
		nl=0;
		if (sk != NULL)
			{
			for (i=0; i<sk_X509_NAME_num(sk); i++)
				{
				name=sk_X509_NAME_value(sk,i);
				j=i2d_X509_NAME(name,NULL);
				if (!BUF_MEM_grow_clean(buf,DTLS1_HM_HEADER_LENGTH+n+j+2))
					{
					SSLerr(SSL_F_DTLS1_SEND_CERTIFICATE_REQUEST,ERR_R_BUF_LIB);
					goto err;
					}
				p=(unsigned char *)&(buf->data[DTLS1_HM_HEADER_LENGTH+n]);
				if (!(s->options & SSL_OP_NETSCAPE_CA_DN_BUG))
					{
					s2n(j,p);
					i2d_X509_NAME(name,&p);
					n+=2+j;
					nl+=2+j;
					}
				else
					{
					d=p;
					i2d_X509_NAME(name,&p);
					j-=2; s2n(j,d); j+=2;
					n+=j;
					nl+=j;
					}
				}
			}
		/* else no CA names */
		p=(unsigned char *)&(buf->data[DTLS1_HM_HEADER_LENGTH+off]);
		s2n(nl,p);

		d=(unsigned char *)buf->data;
		*(d++)=SSL3_MT_CERTIFICATE_REQUEST;
		l2n3(n,d);
		s2n(s->d1->handshake_write_seq,d);
		s->d1->handshake_write_seq++;

		/* we should now have things packed up, so lets send
		 * it off */

		s->init_num=n+DTLS1_HM_HEADER_LENGTH;
		s->init_off=0;
#ifdef NETSCAPE_HANG_BUG
/* XXX: what to do about this? */
		p=(unsigned char *)s->init_buf->data + s->init_num;

		/* do the header */
		*(p++)=SSL3_MT_SERVER_DONE;
		*(p++)=0;
		*(p++)=0;
		*(p++)=0;
		s->init_num += 4;
#endif

		/* XDTLS:  set message header ? */
		msg_len = s->init_num - DTLS1_HM_HEADER_LENGTH;
		dtls1_set_message_header(s, (void *)s->init_buf->data,
			SSL3_MT_CERTIFICATE_REQUEST, msg_len, 0, msg_len);

		/* buffer the message to handle re-xmits */
		dtls1_buffer_message(s, 0);

		s->state = SSL3_ST_SW_CERT_REQ_B;
		}

	/* SSL3_ST_SW_CERT_REQ_B */
	return(dtls1_do_write(s,SSL3_RT_HANDSHAKE));
err:
	return(-1);
	}

int dtls1_send_server_certificate(SSL *s)
	{
	unsigned long l;
	X509 *x;

	if (s->state == SSL3_ST_SW_CERT_A)
		{
		x=ssl_get_server_send_cert(s);
		if (x == NULL)
			{
			/* VRS: allow null cert if auth == KRB5 */
			if ((s->s3->tmp.new_cipher->algorithm_mkey != SSL_kKRB5) ||
			    (s->s3->tmp.new_cipher->algorithm_auth != SSL_aKRB5))
				{
				SSLerr(SSL_F_DTLS1_SEND_SERVER_CERTIFICATE,ERR_R_INTERNAL_ERROR);
				return(0);
				}
			}

		l=dtls1_output_cert_chain(s,x);
		s->state=SSL3_ST_SW_CERT_B;
		s->init_num=(int)l;
		s->init_off=0;

		/* buffer the message to handle re-xmits */
		dtls1_buffer_message(s, 0);
		}

	/* SSL3_ST_SW_CERT_B */
	return(dtls1_do_write(s,SSL3_RT_HANDSHAKE));
	}