1 /*************************************************************************** 2 * Copyright (c) 2024 Microsoft Corporation 3 * 4 * This program and the accompanying materials are made available under the 5 * terms of the MIT License which is available at 6 * https://opensource.org/licenses/MIT. 7 * 8 * SPDX-License-Identifier: MIT 9 **************************************************************************/ 10 11 12 /**************************************************************************/ 13 /**************************************************************************/ 14 /** */ 15 /** NetX Component */ 16 /** */ 17 /** Transmission Control Protocol (TCP) */ 18 /** */ 19 /**************************************************************************/ 20 /**************************************************************************/ 21 22 #define NX_SOURCE_CODE 23 24 25 /* Include necessary system files. */ 26 27 #include "nx_api.h" 28 #include "nx_tcp.h" 29 #include "nx_packet.h" 30 31 32 /**************************************************************************/ 33 /* */ 34 /* FUNCTION RELEASE */ 35 /* */ 36 /* _nx_tcp_socket_bytes_available PORTABLE C */ 37 /* 6.1 */ 38 /* AUTHOR */ 39 /* */ 40 /* Yuxin Zhou, Microsoft Corporation */ 41 /* */ 42 /* DESCRIPTION */ 43 /* */ 44 /* This function determines the number of bytes available on a TCP */ 45 /* socket for reception. */ 46 /* */ 47 /* INPUT */ 48 /* */ 49 /* socket_ptr Pointer to the TCP sockete */ 50 /* bytes_available Number of bytes returned to */ 51 /* the caller. */ 52 /* */ 53 /* OUTPUT */ 54 /* */ 55 /* status Completion status */ 56 /* */ 57 /* CALLS */ 58 /* */ 59 /* tx_mutex_get Obtain protection */ 60 /* tx_mutex_put Release protection */ 61 /* */ 62 /* CALLED BY */ 63 /* */ 64 /* Application Code */ 65 /* */ 66 /* RELEASE HISTORY */ 67 /* */ 68 /* DATE NAME DESCRIPTION */ 69 /* */ 70 /* 05-19-2020 Yuxin Zhou Initial Version 6.0 */ 71 /* 09-30-2020 Yuxin Zhou Modified comment(s), */ 72 /* resulting in version 6.1 */ 73 /* */ 74 /**************************************************************************/ _nx_tcp_socket_bytes_available(NX_TCP_SOCKET * socket_ptr,ULONG * bytes_available)75UINT _nx_tcp_socket_bytes_available(NX_TCP_SOCKET *socket_ptr, ULONG *bytes_available) 76 { 77 NX_IP *ip_ptr; 78 NX_PACKET *packet_ptr; 79 UINT data_size; 80 NX_TCP_HEADER *header_ptr; 81 UINT header_length; 82 INT done = 0; 83 84 /* Setup IP pointer. */ 85 ip_ptr = socket_ptr -> nx_tcp_socket_ip_ptr; 86 87 /* Obtain the IP mutex so we can examine the bound port. */ 88 tx_mutex_get(&(ip_ptr -> nx_ip_protection), TX_WAIT_FOREVER); 89 90 *bytes_available = 0; 91 92 93 /* Make sure the TCP connection has been established. */ 94 if ((socket_ptr -> nx_tcp_socket_state <= NX_TCP_LISTEN_STATE) || 95 (socket_ptr -> nx_tcp_socket_state > NX_TCP_ESTABLISHED)) 96 { 97 /* Release protection. */ 98 tx_mutex_put(&(ip_ptr -> nx_ip_protection)); 99 100 return(NX_NOT_CONNECTED); 101 } 102 103 packet_ptr = socket_ptr -> nx_tcp_socket_receive_queue_head; 104 105 if (packet_ptr == NX_NULL) 106 { 107 108 /* The receive queue is empty. */ 109 /* Release protection. */ 110 tx_mutex_put(&(ip_ptr -> nx_ip_protection)); 111 112 return(NX_SUCCESS); 113 } 114 115 /* Loop through all the packets on the queue and find out the total 116 number of bytes in the rx queue that are available to the applciation. */ 117 do 118 { 119 /*lint -e{923} suppress cast of ULONG to pointer. */ 120 if (packet_ptr -> nx_packet_queue_next == ((NX_PACKET *)NX_PACKET_READY)) 121 { 122 123 /* Compute the size of TCP payload in this packet */ 124 /*lint -e{927} -e{826} suppress cast of pointer to pointer, since it is necessary */ 125 header_ptr = (NX_TCP_HEADER *)packet_ptr -> nx_packet_prepend_ptr; 126 127 /* Calculate the header size for this packet. */ 128 header_length = (UINT)((header_ptr -> nx_tcp_header_word_3 >> NX_TCP_HEADER_SHIFT) * sizeof(ULONG)); 129 130 data_size = (UINT)(packet_ptr -> nx_packet_length - header_length); 131 *bytes_available += data_size; 132 133 if (packet_ptr == socket_ptr -> nx_tcp_socket_receive_queue_tail) 134 { 135 /* Already reached the last packet. */ 136 done = 1; 137 } 138 else 139 { 140 /* Move on to the next packet. */ 141 packet_ptr = packet_ptr -> nx_packet_union_next.nx_packet_tcp_queue_next; 142 } 143 } 144 else 145 { 146 /* If the packet has not been acked yet, then just return the 147 amount of bytes available so far. */ 148 done = 1; 149 } 150 } while (!done); 151 152 /* Release protection. */ 153 tx_mutex_put(&(ip_ptr -> nx_ip_protection)); 154 155 return(NX_SUCCESS); 156 } 157 158
