/* This function is like recv(with MSG_PEEK). But it does not return -1 on error.
* It does return gnutls_errno instead.
* This function reads data from the socket and keeps them in a buffer, of up to
* MAX_RECV_SIZE.
*
* This is not a general purpose function. It returns EXACTLY the data requested,
* which are stored in a local (in the session) buffer.
*
*/
ssize_t
_gnutls_io_read_buffered (gnutls_session_t session, size_t total,
content_type_t recv_type)
{
ssize_t ret = 0;
size_t min;
mbuffer_st *bufel = NULL;
size_t recvdata, readsize;
if (total > MAX_RECV_SIZE(session) || total == 0)
{
gnutls_assert (); /* internal error */
return GNUTLS_E_INVALID_REQUEST;
}
/* calculate the actual size, ie. get the minimum of the
* buffered data and the requested data.
*/
min = MIN (session->internals.record_recv_buffer.byte_length, total);
if (min > 0)
{
/* if we have enough buffered data
* then just return them.
*/
if (min == total)
{
return min;
}
}
/* min is over zero. recvdata is the data we must
* receive in order to return the requested data.
*/
recvdata = total - min;
readsize = recvdata;
/* Check if the previously read data plus the new data to
* receive are longer than the maximum receive buffer size.
*/
if ((session->internals.record_recv_buffer.byte_length + recvdata) >
MAX_RECV_SIZE(session))
{
gnutls_assert (); /* internal error */
return GNUTLS_E_INVALID_REQUEST;
}
if (ret < 0)
{
gnutls_assert ();
return ret;
}
/* READ DATA - but leave RCVLOWAT bytes in the kernel buffer.
*/
if (readsize > 0)
{
ret =
_gnutls_read (session, &bufel, readsize,
session->internals.pull_func);
/* return immediately if we got an interrupt or eagain
* error.
*/
if (ret < 0 && gnutls_error_is_fatal (ret) == 0)
{
_mbuffer_xfree (&bufel);
return ret;
}
}
/* copy fresh data to our buffer.
*/
if (ret > 0)
{
_gnutls_read_log
("RB: Have %d bytes into buffer. Adding %d bytes.\n",
(int) session->internals.record_recv_buffer.byte_length, (int) ret);
_gnutls_read_log ("RB: Requested %d bytes\n", (int) total);
_mbuffer_enqueue (&session->internals.record_recv_buffer, bufel);
}
else
_mbuffer_xfree (&bufel);
if (ret < 0)
{
gnutls_assert ();
return ret;
}
if (ret == 0)
{ /* EOF */
gnutls_assert ();
return 0;
}
if(IS_DTLS(session))
ret = MIN(total, session->internals.record_recv_buffer.byte_length);
else
ret = session->internals.record_recv_buffer.byte_length;
if ((ret > 0) && ((size_t) ret < total))
{
/* Short Read */
return gnutls_assert_val(GNUTLS_E_AGAIN);
}
else
{
return ret;
}
}
static int recv_headers( gnutls_session_t session, content_type_t type,
gnutls_handshake_description_t htype,
struct tls_record_st* record,
unsigned int *ms)
{
int ret;
gnutls_datum_t raw; /* raw headers */
/* Read the headers.
*/
record->header_size = record->packet_size = RECORD_HEADER_SIZE(session);
ret =
_gnutls_io_read_buffered (session, record->header_size, -1, ms);
if (ret != record->header_size)
{
if (ret < 0 && gnutls_error_is_fatal (ret) == 0)
return ret;
if (ret > 0)
ret = GNUTLS_E_UNEXPECTED_PACKET_LENGTH;
else if (ret == 0)
ret = GNUTLS_E_PREMATURE_TERMINATION;
return gnutls_assert_val(ret);
}
ret = _mbuffer_linearize (&session->internals.record_recv_buffer);
if (ret < 0)
return gnutls_assert_val(ret);
_mbuffer_head_get_first (&session->internals.record_recv_buffer, &raw);
if (raw.size < RECORD_HEADER_SIZE(session))
return gnutls_assert_val(GNUTLS_E_UNEXPECTED_PACKET_LENGTH);
record_read_headers (session, raw.data, type, htype, record);
/* Check if the DTLS epoch is valid */
if (IS_DTLS(session))
{
if (_gnutls_epoch_is_valid(session, record->epoch) == 0)
{
_gnutls_audit_log(session, "Discarded message[%u] with invalid epoch %u.\n",
(unsigned int)_gnutls_uint64touint32 (&record->sequence),
(unsigned int)record->sequence.i[0]*256+(unsigned int)record->sequence.i[1]);
gnutls_assert();
/* doesn't matter, just a fatal error */
return GNUTLS_E_UNEXPECTED_PACKET_LENGTH;
}
}
/* Here we check if the Type of the received packet is
* ok.
*/
if ((ret = check_recv_type (session, record->type)) < 0)
return gnutls_assert_val(ret);
/* Here we check if the advertized version is the one we
* negotiated in the handshake.
*/
if ((ret = record_check_version (session, htype, record->version)) < 0)
return gnutls_assert_val(ret);
if (record->length > MAX_RECV_SIZE(session))
{
_gnutls_audit_log
(session, "Received packet with illegal length: %u\n", (unsigned int)record->length);
return gnutls_assert_val(GNUTLS_E_UNEXPECTED_PACKET_LENGTH);
}
_gnutls_record_log
("REC[%p]: Expected Packet %s(%d)\n", session,
_gnutls_packet2str (type), type);
_gnutls_record_log ("REC[%p]: Received Packet %s(%d) with length: %d\n",
session,
_gnutls_packet2str (record->type), record->type, record->length);
return 0;
}
static ssize_t
_gnutls_dgram_read (gnutls_session_t session, mbuffer_st **bufel,
gnutls_pull_func pull_func)
{
ssize_t i, ret;
char *ptr;
size_t max_size = _gnutls_get_max_decrypted_data(session);
size_t recv_size = MAX_RECV_SIZE(session);
gnutls_transport_ptr_t fd = session->internals.transport_recv_ptr;
if (recv_size > max_size)
recv_size = max_size;
*bufel = _mbuffer_alloc (0, max_size);
if (*bufel == NULL)
return gnutls_assert_val(GNUTLS_E_MEMORY_ERROR);
ptr = (*bufel)->msg.data;
session->internals.direction = 0;
reset_errno (session);
i = pull_func (fd, ptr, recv_size);
if (i < 0)
{
int err = get_errno (session);
_gnutls_read_log ("READ: %d returned from %p, errno=%d gerrno=%d\n",
(int) i, fd, errno, session->internals.errnum);
if (err == EAGAIN)
{
ret = GNUTLS_E_AGAIN;
goto cleanup;
}
else if (err == EINTR)
{
ret = GNUTLS_E_INTERRUPTED;
goto cleanup;
}
else
{
gnutls_assert ();
ret = GNUTLS_E_PULL_ERROR;
goto cleanup;
}
}
else
{
_gnutls_read_log ("READ: Got %d bytes from %p\n", (int) i, fd);
if (i == 0)
{
/* If we get here, we likely have a stream socket.
* FIXME: this probably breaks DCCP. */
gnutls_assert ();
ret = 0;
goto cleanup;
}
_mbuffer_set_udata_size (*bufel, i);
}
_gnutls_read_log ("READ: read %d bytes from %p\n", (int) i, fd);
return i;
cleanup:
_mbuffer_xfree(bufel);
return ret;
}
