/*
 * 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 <openssl/bn.h>
#include <openssl/buf.h>
#include <openssl/dh.h>
#include <openssl/evp.h>
#include <openssl/md5.h>
#include <openssl/mem.h>
#include <openssl/obj.h>
#include <openssl/rand.h>

#include "ssl_locl.h"

static const SSL_METHOD *dtls1_get_client_method(int ver);
static int dtls1_get_hello_verify(SSL *s);

static const SSL_METHOD *dtls1_get_client_method(int ver)
	{
	if (ver == DTLS1_VERSION)
		return(DTLSv1_client_method());
	else if (ver == DTLS1_2_VERSION)
		return(DTLSv1_2_client_method());
	else
		return(NULL);
	}

IMPLEMENT_dtls1_meth_func(DTLS1_VERSION,
			DTLSv1_client_method,
			ssl_undefined_function,
			dtls1_connect,
			dtls1_get_client_method,
			DTLSv1_enc_data)

IMPLEMENT_dtls1_meth_func(DTLS1_2_VERSION,
			DTLSv1_2_client_method,
			ssl_undefined_function,
			dtls1_connect,
			dtls1_get_client_method,
			DTLSv1_2_enc_data)

IMPLEMENT_dtls1_meth_func(DTLS_ANY_VERSION,
			DTLS_client_method,
			ssl_undefined_function,
			dtls1_connect,
			dtls1_get_client_method,
			DTLSv1_2_enc_data)

int dtls1_connect(SSL *s)
	{
	BUF_MEM *buf=NULL;
	void (*cb)(const SSL *ssl,int type,int val)=NULL;
	int ret= -1;
	int new_state,state,skip=0;

	ERR_clear_error();
	ERR_clear_system_error();

	if (s->info_callback != NULL)
		cb=s->info_callback;
	else if (s->ctx->info_callback != NULL)
		cb=s->ctx->info_callback;
	
	s->in_handshake++;
	if (!SSL_in_init(s) || SSL_in_before(s)) SSL_clear(s); 

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

		switch(s->state)
			{
		case SSL_ST_RENEGOTIATE:
			s->renegotiate=1;
			s->state=SSL_ST_CONNECT;
			s->ctx->stats.sess_connect_renegotiate++;
			/* break */
		case SSL_ST_BEFORE:
		case SSL_ST_CONNECT:
		case SSL_ST_BEFORE|SSL_ST_CONNECT:
		case SSL_ST_OK|SSL_ST_CONNECT:

			s->server=0;
			if (cb != NULL) cb(s,SSL_CB_HANDSHAKE_START,1);

			if ((s->version & 0xff00 ) != (DTLS1_VERSION & 0xff00))
				{
				OPENSSL_PUT_ERROR(SSL, dtls1_connect, ERR_R_INTERNAL_ERROR);
				ret = -1;
				goto end;
				}
				
			/* s->version=SSL3_VERSION; */
			s->type=SSL_ST_CONNECT;

			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;
				buf=NULL;
				}

			if (!ssl3_setup_buffers(s)) { ret= -1; goto end; }

			/* setup buffing BIO */
			if (!ssl_init_wbio_buffer(s,0)) { ret= -1; goto end; }

			/* don't push the buffering BIO quite yet */

			s->state=SSL3_ST_CW_CLNT_HELLO_A;
			s->ctx->stats.sess_connect++;
			s->init_num=0;
			s->d1->send_cookie = 0;
			s->hit = 0;
			break;

		case SSL3_ST_CW_CLNT_HELLO_A:
		case SSL3_ST_CW_CLNT_HELLO_B:

			s->shutdown=0;

			/* every DTLS ClientHello resets Finished MAC */
			ssl3_init_finished_mac(s);

			dtls1_start_timer(s);
			ret=ssl3_client_hello(s);
			if (ret <= 0) goto end;

			if ( s->d1->send_cookie)
				{
				s->state=SSL3_ST_CW_FLUSH;
				s->s3->tmp.next_state=SSL3_ST_CR_SRVR_HELLO_A;
				}
			else
				s->state=DTLS1_ST_CR_HELLO_VERIFY_REQUEST_A;

			s->init_num=0;
				/* turn on buffering for the next lot of output */
				if (s->bbio != s->wbio)
					s->wbio=BIO_push(s->bbio,s->wbio);

			break;

		case DTLS1_ST_CR_HELLO_VERIFY_REQUEST_A:
		case DTLS1_ST_CR_HELLO_VERIFY_REQUEST_B:

			ret = dtls1_get_hello_verify(s);
			if ( ret <= 0)
				goto end;
			if ( s->d1->send_cookie)
				{
				/* start again, with a cookie */
				dtls1_stop_timer(s);
				s->state = SSL3_ST_CW_CLNT_HELLO_A;
				}
			else
				{
				s->state = SSL3_ST_CR_SRVR_HELLO_A;
				}
			s->init_num = 0;
			break;

		case SSL3_ST_CR_SRVR_HELLO_A:
		case SSL3_ST_CR_SRVR_HELLO_B:
			ret=ssl3_get_server_hello(s);
			if (ret <= 0) goto end;

			if (s->hit)
				{
				s->state=SSL3_ST_CR_FINISHED_A;
				if (s->tlsext_ticket_expected)
					{
					/* receive renewed session ticket */
					s->state=SSL3_ST_CR_SESSION_TICKET_A;
					}
				}
			else
				{
				s->state=SSL3_ST_CR_CERT_A;
				}
			s->init_num=0;
			break;

		case SSL3_ST_CR_CERT_A:
		case SSL3_ST_CR_CERT_B:
			if (ssl_cipher_has_server_public_key(s->s3->tmp.new_cipher))
				{
				ret=ssl3_get_server_certificate(s);
				if (ret <= 0) goto end;
				if (s->tlsext_status_expected)
					s->state=SSL3_ST_CR_CERT_STATUS_A;
				else
					s->state=SSL3_ST_CR_KEY_EXCH_A;
				}
			else
				{
				skip = 1;
				s->state=SSL3_ST_CR_KEY_EXCH_A;
				}
			s->init_num=0;
			break;

		case SSL3_ST_CR_KEY_EXCH_A:
		case SSL3_ST_CR_KEY_EXCH_B:
			ret=ssl3_get_server_key_exchange(s);
			if (ret <= 0) goto end;
			s->state=SSL3_ST_CR_CERT_REQ_A;
			s->init_num=0;

			/* at this point we check that we have the
			 * required stuff from the server */
			if (!ssl3_check_cert_and_algorithm(s))
				{
				ret= -1;
				goto end;
				}
			break;

		case SSL3_ST_CR_CERT_REQ_A:
		case SSL3_ST_CR_CERT_REQ_B:
			ret=ssl3_get_certificate_request(s);
			if (ret <= 0) goto end;
			s->state=SSL3_ST_CR_SRVR_DONE_A;
			s->init_num=0;
			break;

		case SSL3_ST_CR_SRVR_DONE_A:
		case SSL3_ST_CR_SRVR_DONE_B:
			ret=ssl3_get_server_done(s);
			if (ret <= 0) goto end;
			dtls1_stop_timer(s);
			if (s->s3->tmp.cert_req)
				s->s3->tmp.next_state=SSL3_ST_CW_CERT_A;
			else
				s->s3->tmp.next_state=SSL3_ST_CW_KEY_EXCH_A;
			s->init_num=0;
			s->state=s->s3->tmp.next_state;
			break;

		case SSL3_ST_CW_CERT_A:
		case SSL3_ST_CW_CERT_B:
		case SSL3_ST_CW_CERT_C:
		case SSL3_ST_CW_CERT_D:
			dtls1_start_timer(s);
			ret=ssl3_send_client_certificate(s);
			if (ret <= 0) goto end;
			s->state=SSL3_ST_CW_KEY_EXCH_A;
			s->init_num=0;
			break;

		case SSL3_ST_CW_KEY_EXCH_A:
		case SSL3_ST_CW_KEY_EXCH_B:
			dtls1_start_timer(s);
			ret=ssl3_send_client_key_exchange(s);
			if (ret <= 0) goto end;
			/* For TLS, cert_req is set to 2, so a cert chain
			 * of nothing is sent, but no verify packet is sent */
			if (s->s3->tmp.cert_req == 1)
				{
				s->state=SSL3_ST_CW_CERT_VRFY_A;
				}
			else
				{
				s->state=SSL3_ST_CW_CHANGE_A;
				s->s3->change_cipher_spec=0;
				}

			s->init_num=0;
			break;

		case SSL3_ST_CW_CERT_VRFY_A:
		case SSL3_ST_CW_CERT_VRFY_B:
			dtls1_start_timer(s);
			ret=ssl3_send_client_verify(s);
			if (ret <= 0) goto end;
			s->state=SSL3_ST_CW_CHANGE_A;
			s->init_num=0;
			s->s3->change_cipher_spec=0;
			break;

		case SSL3_ST_CW_CHANGE_A:
		case SSL3_ST_CW_CHANGE_B:
			if (!s->hit)
				dtls1_start_timer(s);
			ret=dtls1_send_change_cipher_spec(s,
				SSL3_ST_CW_CHANGE_A,SSL3_ST_CW_CHANGE_B);
			if (ret <= 0) goto end;

			s->state=SSL3_ST_CW_FINISHED_A;
			s->init_num=0;

			s->session->cipher=s->s3->tmp.new_cipher;
			if (!s->method->ssl3_enc->setup_key_block(s))
				{
				ret= -1;
				goto end;
				}

			if (!s->method->ssl3_enc->change_cipher_state(s,
				SSL3_CHANGE_CIPHER_CLIENT_WRITE))
				{
				ret= -1;
				goto end;
				}
			
			dtls1_reset_seq_numbers(s, SSL3_CC_WRITE);
			break;

		case SSL3_ST_CW_FINISHED_A:
		case SSL3_ST_CW_FINISHED_B:
			if (!s->hit)
				dtls1_start_timer(s);
			ret=ssl3_send_finished(s,
				SSL3_ST_CW_FINISHED_A,SSL3_ST_CW_FINISHED_B,
				s->method->ssl3_enc->client_finished_label,
				s->method->ssl3_enc->client_finished_label_len);
			if (ret <= 0) goto end;
			s->state=SSL3_ST_CW_FLUSH;

			/* clear flags */
			s->s3->flags&= ~SSL3_FLAGS_POP_BUFFER;
			if (s->hit)
				{
				s->s3->tmp.next_state=SSL_ST_OK;
				}
			else
				{

				/* Allow NewSessionTicket if ticket expected */
				if (s->tlsext_ticket_expected)
					s->s3->tmp.next_state=SSL3_ST_CR_SESSION_TICKET_A;
				else
				
				s->s3->tmp.next_state=SSL3_ST_CR_FINISHED_A;
				}
			s->init_num=0;
			break;

		case SSL3_ST_CR_SESSION_TICKET_A:
		case SSL3_ST_CR_SESSION_TICKET_B:
			ret=ssl3_get_new_session_ticket(s);
			if (ret <= 0) goto end;
			s->state=SSL3_ST_CR_FINISHED_A;
			s->init_num=0;
		break;

		case SSL3_ST_CR_CERT_STATUS_A:
		case SSL3_ST_CR_CERT_STATUS_B:
			ret=ssl3_get_cert_status(s);
			if (ret <= 0) goto end;
			s->state=SSL3_ST_CR_KEY_EXCH_A;
			s->init_num=0;
		break;

		case SSL3_ST_CR_FINISHED_A:
		case SSL3_ST_CR_FINISHED_B:
			s->d1->change_cipher_spec_ok = 1;
			ret=ssl3_get_finished(s,SSL3_ST_CR_FINISHED_A,
				SSL3_ST_CR_FINISHED_B);
			if (ret <= 0) goto end;
			dtls1_stop_timer(s);

			if (s->hit)
				s->state=SSL3_ST_CW_CHANGE_A;
			else
				s->state=SSL_ST_OK;

			s->init_num=0;
			break;

		case SSL3_ST_CW_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 SSL_ST_OK:
			/* clean a few things up */
			ssl3_cleanup_key_block(s);

#if 0
			if (s->init_buf != NULL)
				{
				BUF_MEM_free(s->init_buf);
				s->init_buf=NULL;
				}
#endif

			/* If we are not 'joining' the last two packets,
			 * remove the buffering now */
			if (!(s->s3->flags & SSL3_FLAGS_POP_BUFFER))
				ssl_free_wbio_buffer(s);
			/* else do it later in ssl3_write */

			s->init_num=0;
			s->renegotiate=0;
			s->new_session=0;

			ssl_update_cache(s,SSL_SESS_CACHE_CLIENT);
			if (s->hit) s->ctx->stats.sess_hit++;

			ret=1;
			/* s->server=0; */
			s->handshake_func=dtls1_connect;
			s->ctx->stats.sess_connect_good++;

			if (cb != NULL) cb(s,SSL_CB_HANDSHAKE_DONE,1);

			/* done with handshaking */
			s->d1->handshake_read_seq  = 0;
			s->d1->next_handshake_write_seq = 0;
			goto end;
			/* break; */
			
		default:
			OPENSSL_PUT_ERROR(SSL, dtls1_connect, SSL_R_UNKNOWN_STATE);
			ret= -1;
			goto end;
			/* break; */
			}

		/* did we do anything */
		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_CONNECT_LOOP,1);
				s->state=new_state;
				}
			}
		skip=0;
		}
end:
	s->in_handshake--;
	
	if (buf != NULL)
		BUF_MEM_free(buf);
	if (cb != NULL)
		cb(s,SSL_CB_CONNECT_EXIT,ret);
	return(ret);
	}

static int dtls1_get_hello_verify(SSL *s)
	{
	long n;
	int al, ok = 0;
	CBS hello_verify_request, cookie;
	uint16_t server_version;

	s->first_packet = 1;
	n=s->method->ssl_get_message(s,
		DTLS1_ST_CR_HELLO_VERIFY_REQUEST_A,
		DTLS1_ST_CR_HELLO_VERIFY_REQUEST_B,
		-1,
		/* Use the same maximum size as ssl3_get_server_hello. */
		20000,
		&ok);
	s->first_packet = 0;

	if (!ok) return((int)n);

	if (s->s3->tmp.message_type != DTLS1_MT_HELLO_VERIFY_REQUEST)
		{
		s->d1->send_cookie = 0;
		s->s3->tmp.reuse_message = 1;
		return(1);
		}

	CBS_init(&hello_verify_request, s->init_msg, n);

	if (!CBS_get_u16(&hello_verify_request, &server_version) ||
		!CBS_get_u8_length_prefixed(&hello_verify_request, &cookie) ||
		CBS_len(&hello_verify_request) != 0)
		{
		al = SSL_AD_DECODE_ERROR;
		OPENSSL_PUT_ERROR(SSL, ssl3_get_cert_status, SSL_R_DECODE_ERROR);
		goto f_err;
		}

	if (CBS_len(&cookie) > sizeof(s->d1->cookie))
		{
		al=SSL_AD_ILLEGAL_PARAMETER;
		goto f_err;
		}

	memcpy(s->d1->cookie, CBS_data(&cookie), CBS_len(&cookie));
	s->d1->cookie_len = CBS_len(&cookie);

	s->d1->send_cookie = 1;
	return 1;

f_err:
	ssl3_send_alert(s, SSL3_AL_FATAL, al);
	return -1;
	}