d1_both.c

mediastreamer2是开源的网络传输媒体流的库

/* ssl/d1_both.c */
/* 
 * DTLS implementation written by Nagendra Modadugu
 * ([e-mail]) for the OpenSSL project 2005.  
 */
/* ====================================================================
 * Copyright (c) 1998-2005 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
 *    [e-mail].
 *
 * 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
 * ([e-mail]).  This product includes software written by Tim
 * Hudson ([e-mail]).
 *
 */
/* Copyright (C) 1995-1998 Eric Young ([e-mail])
 * All rights reserved.
 *
 * This package is an SSL implementation written
 * by Eric Young ([e-mail]).
 * 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 ([e-mail]).
 * 
 * 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 ([e-mail])"
 *    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 ([e-mail])"
 * 
 * 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 <limits.h>
#include <string.h>
#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>


/* XDTLS:  figure out the right values */
static unsigned int g_probable_mtu[] = {1500 - 28, 512 - 28, 256 - 28};

static unsigned int dtls1_min_mtu(void);
static unsigned int dtls1_guess_mtu(unsigned int curr_mtu);
static void dtls1_fix_message_header(SSL *s, unsigned long frag_off, 
	unsigned long frag_len);
static unsigned char *dtls1_write_message_header(SSL *s,
	unsigned char *p);
static void dtls1_set_message_header_int(SSL *s, unsigned char mt,
	unsigned long len, unsigned short seq_num, unsigned long frag_off, 
	unsigned long frag_len);
static int dtls1_retransmit_buffered_messages(SSL *s);
static long dtls1_get_message_fragment(SSL *s, int st1, int stn, 
    long max, int *ok);
static void dtls1_process_handshake_fragment(SSL *s, int frag_len);

static hm_fragment *
dtls1_hm_fragment_new(unsigned long frag_len)
    {
    hm_fragment *frag = NULL;
    unsigned char *buf = NULL;

    frag = (hm_fragment *)OPENSSL_malloc(sizeof(hm_fragment));
    if ( frag == NULL)
        return NULL;

    buf = (unsigned char *)OPENSSL_malloc(frag_len 
        + DTLS1_HM_HEADER_LENGTH);
    if ( buf == NULL)
        {
        OPENSSL_free(frag);
        return NULL;
        }
    
    frag->fragment = buf;

    return frag;
    }

static void
dtls1_hm_fragment_free(hm_fragment *frag)
    {
    OPENSSL_free(frag->fragment);
    OPENSSL_free(frag);
    }

/* send s->init_buf in records of type 'type' (SSL3_RT_HANDSHAKE or SSL3_RT_CHANGE_CIPHER_SPEC) */
int dtls1_do_write(SSL *s, int type)
	{
	int ret;
	int curr_mtu;
	unsigned int len, frag_off;

	/* AHA!  Figure out the MTU, and stick to the right size */
	if ( ! (SSL_get_options(s) & SSL_OP_NO_QUERY_MTU))
        {
		s->d1->mtu = 
			BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_QUERY_MTU, 0, NULL);

		/* I've seen the kernel return bogus numbers when it doesn't know
		 * (initial write), so just make sure we have a reasonable number */
		if ( s->d1->mtu < dtls1_min_mtu())
			{
			s->d1->mtu = 0;
			s->d1->mtu = dtls1_guess_mtu(s->d1->mtu);
			BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_SET_MTU, 
				s->d1->mtu, NULL);
			}
		}
#if 0 
	mtu = s->d1->mtu;

	fprintf(stderr, "using MTU = %d\n", mtu);

	mtu -= (DTLS1_HM_HEADER_LENGTH + DTLS1_RT_HEADER_LENGTH);

	curr_mtu = mtu - BIO_wpending(SSL_get_wbio(s));

	if ( curr_mtu > 0)
		mtu = curr_mtu;
	else if ( ( ret = BIO_flush(SSL_get_wbio(s))) <= 0)
		return ret;
		
	if ( BIO_wpending(SSL_get_wbio(s)) + s->init_num >= mtu)
		{
		ret = BIO_flush(SSL_get_wbio(s));
		if ( ret <= 0)
			return ret;
		mtu = s->d1->mtu - (DTLS1_HM_HEADER_LENGTH + DTLS1_RT_HEADER_LENGTH);
		}

	OPENSSL_assert(mtu > 0);  /* should have something reasonable now */

#endif

	if ( s->init_off == 0  && type == SSL3_RT_HANDSHAKE)
		OPENSSL_assert(s->init_num == 
			(int)s->d1->w_msg_hdr.msg_len + DTLS1_HM_HEADER_LENGTH);

	frag_off = 0;
	while( s->init_num)
		{
		curr_mtu = s->d1->mtu - BIO_wpending(SSL_get_wbio(s)) - 
			DTLS1_RT_HEADER_LENGTH;

		if ( curr_mtu <= DTLS1_HM_HEADER_LENGTH)
			{
			/* grr.. we could get an error if MTU picked was wrong */
			ret = BIO_flush(SSL_get_wbio(s));
			if ( ret <= 0)
				return ret;
			curr_mtu = s->d1->mtu - DTLS1_RT_HEADER_LENGTH;
			}

		if ( s->init_num > curr_mtu)
			len = curr_mtu;
		else
			len = s->init_num;


		/* XDTLS: this function is too long.  split out the CCS part */
		if ( type == SSL3_RT_HANDSHAKE)
			{
			if ( s->init_off != 0)
				{
				OPENSSL_assert(s->init_off > DTLS1_HM_HEADER_LENGTH);
				s->init_off -= DTLS1_HM_HEADER_LENGTH;
				s->init_num += DTLS1_HM_HEADER_LENGTH;

                /* write atleast DTLS1_HM_HEADER_LENGTH bytes */
				if ( len <= DTLS1_HM_HEADER_LENGTH)  
					len += DTLS1_HM_HEADER_LENGTH;
				}
			
			dtls1_fix_message_header(s, frag_off, 
				len - DTLS1_HM_HEADER_LENGTH);

			dtls1_write_message_header(s, (unsigned char *)&s->init_buf->data[s->init_off]);

			OPENSSL_assert(len >= DTLS1_HM_HEADER_LENGTH);
			}

		ret=dtls1_write_bytes(s,type,&s->init_buf->data[s->init_off],
			len);
		if (ret < 0)
			{
			/* might need to update MTU here, but we don't know
			 * which previous packet caused the failure -- so can't
			 * really retransmit anything.  continue as if everything
			 * is fine and wait for an alert to handle the
			 * retransmit 
			 */
			if ( BIO_ctrl(SSL_get_wbio(s),
				BIO_CTRL_DGRAM_MTU_EXCEEDED, 0, NULL))
				s->d1->mtu = BIO_ctrl(SSL_get_wbio(s),
					BIO_CTRL_DGRAM_QUERY_MTU, 0, NULL);
			else
				return(-1);
			}
		else
			{
			
			/* bad if this assert fails, only part of the handshake
			 * message got sent.  but why would this happen? */
			OPENSSL_assert(len == (unsigned int)ret); 
			
			if (type == SSL3_RT_HANDSHAKE && ! s->d1->retransmitting)
				/* should not be done for 'Hello Request's, but in that case
				 * we'll ignore the result anyway */
				ssl3_finish_mac(s, 
					(unsigned char *)&s->init_buf->data[s->init_off + 
						DTLS1_HM_HEADER_LENGTH], ret - DTLS1_HM_HEADER_LENGTH);
			
			if (ret == s->init_num)
				{
				if (s->msg_callback)
					s->msg_callback(1, s->version, type, s->init_buf->data, 
						(size_t)(s->init_off + s->init_num), s, 
						s->msg_callback_arg);

				s->init_off = 0;  /* done writing this message */
				s->init_num = 0;
				
				return(1);
				}
			s->init_off+=ret;
			s->init_num-=ret;
			frag_off += (ret -= DTLS1_HM_HEADER_LENGTH);
			}
		}
	return(0);
	}


/* Obtain handshake message of message type 'mt' (any if mt == -1),
 * maximum acceptable body length 'max'.
 * Read an entire handshake message.  Handshake messages arrive in
 * fragments.
 */
long dtls1_get_message(SSL *s, int st1, int stn, int mt, long max, int *ok)
	{
	int i, al;

	/* s3->tmp is used to store messages that are unexpected, caused
	 * by the absence of an optional handshake message */
	if (s->s3->tmp.reuse_message)
		{
		s->s3->tmp.reuse_message=0;
		if ((mt >= 0) && (s->s3->tmp.message_type != mt))
			{
			al=SSL_AD_UNEXPECTED_MESSAGE;
			SSLerr(SSL_F_DTLS1_GET_MESSAGE,SSL_R_UNEXPECTED_MESSAGE);
			goto f_err;
			}
		*ok=1;
		s->init_msg = s->init_buf->data + DTLS1_HM_HEADER_LENGTH;
		s->init_num = (int)s->s3->tmp.message_size;
		return s->init_num;
		}
	
	do
		{
		if ( s->d1->r_msg_hdr.frag_off == 0)
			{
			/* s->d1->r_message_header.msg_len = 0; */
			memset(&(s->d1->r_msg_hdr), 0x00, sizeof(struct hm_header_st));
			}

		i = dtls1_get_message_fragment(s, st1, stn, max, ok);
		if ( i == DTLS1_HM_BAD_FRAGMENT ||
            i == DTLS1_HM_FRAGMENT_RETRY)  /* bad fragment received */
			continue;
		else if ( i <= 0 && !*ok)
			return i;

		if (s->d1->r_msg_hdr.msg_len == (unsigned int)s->init_num - DTLS1_HM_HEADER_LENGTH)
			{
			memset(&(s->d1->r_msg_hdr), 0x00, sizeof(struct hm_header_st));

			s->d1->handshake_read_seq++;
			/* we just read a handshake message from the other side:
			 * this means that we don't need to retransmit of the
			 * buffered messages.  
			 * XDTLS: may be able clear out this
			 * buffer a little sooner (i.e if an out-of-order
			 * handshake message/record is received at the record
			 * layer.  
			 * XDTLS: exception is that the server needs to
			 * know that change cipher spec and finished messages
			 * have been received by the client before clearing this
			 * buffer.  this can simply be done by waiting for the
			 * first data  segment, but is there a better way?  */
			dtls1_clear_record_buffer(s);

            s->init_msg = s->init_buf->data + DTLS1_HM_HEADER_LENGTH;
			return s->init_num - DTLS1_HM_HEADER_LENGTH;
			}
		else
			s->d1->r_msg_hdr.frag_off = i;
		} while(1) ;

f_err:
	ssl3_send_alert(s,SSL3_AL_FATAL,al);
	*ok = 0;
	return -1;
	}


static int
dtls1_retrieve_buffered_fragment(SSL *s, unsigned long *copied)
    {
    /* (0) check whether the desired fragment is available
     * if so:
     * (1) copy over the fragment to s->init_buf->data[]
     * (2) update s->init_num
     */
    pitem *item;
    hm_fragment *frag;
    unsigned long overlap;
    unsigned char *p;

    item = pqueue_peek(s->d1->buffered_messages);
    if ( item == NULL)
        return 0;

    frag = (hm_fragment *)item->data;
    
    if ( s->d1->handshake_read_seq == frag->msg_header.seq &&
        frag->msg_header.frag_off <= (unsigned int)s->init_num - DTLS1_HM_HEADER_LENGTH)
        {
        pqueue_pop(s->d1->buffered_messages);
        overlap = s->init_num - DTLS1_HM_HEADER_LENGTH 
            - frag->msg_header.frag_off;

        p = frag->fragment;