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/***************************************************************************
* Copyright (c) 2024 Microsoft Corporation
* Copyright (c) 2025-present Eclipse ThreadX Contributors
*
* This program and the accompanying materials are made available under the
* terms of the MIT License which is available at
* https://opensource.org/licenses/MIT.
*
* SPDX-License-Identifier: MIT
**************************************************************************/
/**************************************************************************/
/**************************************************************************/
/** */
/** NetX Component */
/** */
/** Transmission Control Protocol (TCP) */
/** */
/**************************************************************************/
/**************************************************************************/
#define NX_SOURCE_CODE
/* Include necessary system files. */
#include "nx_api.h"
#include "nx_tcp.h"
#include "nx_packet.h"
/**************************************************************************/
/* */
/* FUNCTION RELEASE */
/* */
/* _nx_tcp_socket_bytes_available PORTABLE C */
/* 6.4.3 */
/* AUTHOR */
/* */
/* Yuxin Zhou, Microsoft Corporation */
/* */
/* DESCRIPTION */
/* */
/* This function determines the number of bytes available on a TCP */
/* socket for reception. */
/* */
/* INPUT */
/* */
/* socket_ptr Pointer to the TCP sockete */
/* bytes_available Number of bytes returned to */
/* the caller. */
/* */
/* OUTPUT */
/* */
/* status Completion status */
/* */
/* CALLS */
/* */
/* tx_mutex_get Obtain protection */
/* tx_mutex_put Release protection */
/* */
/* CALLED BY */
/* */
/* Application Code */
/* */
/**************************************************************************/
UINT _nx_tcp_socket_bytes_available(NX_TCP_SOCKET *socket_ptr, ULONG *bytes_available)
{
NX_IP *ip_ptr;
NX_PACKET *packet_ptr;
UINT data_size;
NX_TCP_HEADER *header_ptr;
UINT header_length;
INT done = 0;
/* Setup IP pointer. */
ip_ptr = socket_ptr -> nx_tcp_socket_ip_ptr;
/* Obtain the IP mutex so we can examine the bound port. */
tx_mutex_get(&(ip_ptr -> nx_ip_protection), TX_WAIT_FOREVER);
*bytes_available = 0;
/* Make sure the TCP connection has been established. */
if ((socket_ptr -> nx_tcp_socket_state <= NX_TCP_LISTEN_STATE) ||
(socket_ptr -> nx_tcp_socket_state > NX_TCP_ESTABLISHED))
{
/* Release protection. */
tx_mutex_put(&(ip_ptr -> nx_ip_protection));
return(NX_NOT_CONNECTED);
}
packet_ptr = socket_ptr -> nx_tcp_socket_receive_queue_head;
if (packet_ptr == NX_NULL)
{
/* The receive queue is empty. */
/* Release protection. */
tx_mutex_put(&(ip_ptr -> nx_ip_protection));
return(NX_SUCCESS);
}
/* Loop through all the packets on the queue and find out the total
number of bytes in the rx queue that are available to the applciation. */
do
{
/*lint -e{923} suppress cast of ULONG to pointer. */
if (packet_ptr -> nx_packet_queue_next == ((NX_PACKET *)NX_PACKET_READY))
{
/* Compute the size of TCP payload in this packet */
/*lint -e{927} -e{826} suppress cast of pointer to pointer, since it is necessary */
header_ptr = (NX_TCP_HEADER *)packet_ptr -> nx_packet_prepend_ptr;
/* Calculate the header size for this packet. */
header_length = (UINT)((header_ptr -> nx_tcp_header_word_3 >> NX_TCP_HEADER_SHIFT) * sizeof(ULONG));
data_size = (UINT)(packet_ptr -> nx_packet_length - header_length);
*bytes_available += data_size;
if (packet_ptr == socket_ptr -> nx_tcp_socket_receive_queue_tail)
{
/* Already reached the last packet. */
done = 1;
}
else
{
/* Move on to the next packet. */
packet_ptr = packet_ptr -> nx_packet_union_next.nx_packet_tcp_queue_next;
}
}
else
{
/* If the packet has not been acked yet, then just return the
amount of bytes available so far. */
done = 1;
}
} while (!done);
/* Release protection. */
tx_mutex_put(&(ip_ptr -> nx_ip_protection));
return(NX_SUCCESS);
}
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