AuroraMiddleware/mbedtls
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Implement support for MTU setting

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This commit is contained in:
Manuel Pégourié-Gonnard 2017-09-21 13:49:50 +02:00
parent 0b1d9b2c75
commit 9468ff1966
2 changed files with 92 additions and 20 deletions
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43
include/mbedtls/ssl.h
View File

@ -2430,6 +2430,7 @@ void mbedtls_ssl_conf_cert_req_ca_list( mbedtls_ssl_config *conf,
#if defined(MBEDTLS_SSL_PROTO_DTLS)
/**
* \brief Set the Maximum Tranport Unit (MTU).
* Special value: 0 means unset (no limit).
* This represents the maximum size of a datagram payload
* handled by the transport layer (usually UDP) as determined
* by the network link and stack. In practice, this controls
@ -2446,7 +2447,8 @@ void mbedtls_ssl_conf_cert_req_ca_list( mbedtls_ssl_config *conf,
*
* \note Values larger than \c MBEDTLS_SSL_OUT_CONTENT_LEN have no
* effect. This can only be used to decrease the maximum size
* of detagrams sent.
* of datagrams sent. Values lower than record layer expansion
* are ignored.
*
* \param conf SSL configuration
* \param mtu Value of the path MTU in bytes
@ -2738,6 +2740,9 @@ const char *mbedtls_ssl_get_version( const mbedtls_ssl_context *ssl );
* \brief Return the (maximum) number of bytes added by the record
* layer: header + encryption/MAC overhead (inc. padding)
*
* \note This function is not available (always returns an error)
* when record compression is enabled.
*
* \param ssl SSL context
*
* \return Current maximum record expansion in bytes, or
@ -2752,12 +2757,8 @@ int mbedtls_ssl_get_record_expansion( const mbedtls_ssl_context *ssl );
* This is the value negotiated with peer if any,
* or the locally configured value.
*
* \note With DTLS, \c mbedtls_ssl_write() will return an error if
* called with a larger length value.
* With TLS, \c mbedtls_ssl_write() will fragment the input if
* necessary and return the number of bytes written; it is up
* to the caller to call \c mbedtls_ssl_write() again in
* order to send the remaining bytes if any.
* \sa mbedtls_ssl_conf_max_frag_len()
* \sa mbedtls_ssl_get_max_record_payload()
*
* \param ssl SSL context
*
@ -2766,6 +2767,34 @@ int mbedtls_ssl_get_record_expansion( const mbedtls_ssl_context *ssl );
size_t mbedtls_ssl_get_max_frag_len( const mbedtls_ssl_context *ssl );
#endif /* MBEDTLS_SSL_MAX_FRAGMENT_LENGTH */
/**
* \brief Return the current maximum outgoing record payload in bytes.
* This takes into account the config.h setting \c
* MBEDTLS_SSL_OUT_CONTENT_LEN, the configured and negotiated
* max fragment length extension if used, and for DTLS the
* path MTU as configured and current record expansion.
*
* \note With DTLS, \c mbedtls_ssl_write() will return an error if
* called with a larger length value.
* With TLS, \c mbedtls_ssl_write() will fragment the input if
* necessary and return the number of bytes written; it is up
* to the caller to call \c mbedtls_ssl_write() again in
* order to send the remaining bytes if any.
*
* \note This function is not available (always returns an error)
* when record compression is enabled.
*
* \sa mbedtls_ssl_conf_mtu()
* \sa mbedtls_ssl_get_max_frag_len()
* \sa mbedtls_ssl_get_record_expansion()
*
* \param ssl SSL context
*
* \return Current maximum payload for an outgoing record,
* or a negative error code.
*/
int mbedtls_ssl_get_max_out_record_payload( const mbedtls_ssl_context *ssl );
#if defined(MBEDTLS_X509_CRT_PARSE_C)
/**
* \brief Return the peer certificate from the current connection

69
library/ssl_tls.c
View File

@ -2845,16 +2845,20 @@ int mbedtls_ssl_resend( mbedtls_ssl_context *ssl )
*/
int mbedtls_ssl_flight_transmit( mbedtls_ssl_context *ssl )
{
#if defined(MBEDTLS_SSL_MAX_FRAGMENT_LENGTH)
const size_t max_record_content_len = mbedtls_ssl_get_max_frag_len( ssl );
#else
const size_t max_record_content_len = MBEDTLS_SSL_OUT_CONTENT_LEN;
#endif
const int ret_payload = mbedtls_ssl_get_max_out_record_payload( ssl );
const size_t max_record_payload = (size_t) ret_payload;
/* DTLS handshake headers are 12 bytes */
const size_t max_hs_fragment_len = max_record_content_len - 12;
const size_t max_hs_fragment_len = max_record_payload - 12;
MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> mbedtls_ssl_flight_transmit" ) );
if( ret_payload < 0 )
{
MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_get_max_out_record_payload",
ret_payload );
return( ret_payload );
}
if( ssl->handshake->retransmit_state != MBEDTLS_SSL_RETRANS_SENDING )
{
MBEDTLS_SSL_DEBUG_MSG( 2, ( "initialise fligh transmission" ) );
@ -7008,6 +7012,7 @@ int mbedtls_ssl_get_record_expansion( const mbedtls_ssl_context *ssl )
#if defined(MBEDTLS_ZLIB_SUPPORT)
if( ssl->session_out->compression != MBEDTLS_SSL_COMPRESS_NULL )
return( MBEDTLS_ERR_SSL_FEATURE_UNAVAILABLE );
}
#endif
switch( mbedtls_cipher_get_cipher_mode( &transform->cipher_ctx_enc ) )
@ -7055,10 +7060,45 @@ size_t mbedtls_ssl_get_max_frag_len( const mbedtls_ssl_context *ssl )
max_len = ssl_mfl_code_to_length( ssl->session_negotiate->mfl_code );
}
return max_len;
return( max_len );
}
#endif /* MBEDTLS_SSL_MAX_FRAGMENT_LENGTH */
int mbedtls_ssl_get_max_out_record_payload( const mbedtls_ssl_context *ssl )
{
size_t max_len = MBEDTLS_SSL_OUT_CONTENT_LEN;
#if defined(MBEDTLS_SSL_MAX_FRAGMENT_LENGTH)
const size_t mfl = mbedtls_ssl_get_max_frag_len( ssl );
if( max_len > mfl )
max_len = mfl;
#endif
#if defined(MBEDTLS_SSL_PROTO_DTLS)
if( ssl->conf->mtu != 0 )
{
const size_t mtu = ssl->conf->mtu;
const int ret = mbedtls_ssl_get_record_expansion( ssl );
const size_t overhead = (size_t) ret;
if( ret < 0 )
return( ret );
if( mtu <= overhead )
{
MBEDTLS_SSL_DEBUG_MSG( 1, ( "MTU too low for record expansion" ) );
return( MBEDTLS_ERR_SSL_FEATURE_UNAVAILABLE );
}
if( max_len > mtu - overhead )
max_len = mtu - overhead;
}
#endif
return( (int) max_len );
}
#if defined(MBEDTLS_X509_CRT_PARSE_C)
const mbedtls_x509_crt *mbedtls_ssl_get_peer_cert( const mbedtls_ssl_context *ssl )
{
@ -7610,12 +7650,15 @@ int mbedtls_ssl_read( mbedtls_ssl_context *ssl, unsigned char *buf, size_t len )
static int ssl_write_real( mbedtls_ssl_context *ssl,
const unsigned char *buf, size_t len )
{
int ret;
#if defined(MBEDTLS_SSL_MAX_FRAGMENT_LENGTH)
size_t max_len = mbedtls_ssl_get_max_frag_len( ssl );
#else
size_t max_len = MBEDTLS_SSL_OUT_CONTENT_LEN;
#endif /* MBEDTLS_SSL_MAX_FRAGMENT_LENGTH */
int ret = mbedtls_ssl_get_max_out_record_payload( ssl );
const size_t max_len = (size_t) ret;
if( ret < 0 )
{
MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_get_max_out_record_payload", ret );
return( ret );
}
if( len > max_len )
{
#if defined(MBEDTLS_SSL_PROTO_DTLS)