1 /**************************************************************************/ 2 /* */ 3 /* Copyright (c) Microsoft Corporation. All rights reserved. */ 4 /* */ 5 /* This software is licensed under the Microsoft Software License */ 6 /* Terms for Microsoft Azure RTOS. Full text of the license can be */ 7 /* found in the LICENSE file at https://aka.ms/AzureRTOS_EULA */ 8 /* and in the root directory of this software. */ 9 /* */ 10 /**************************************************************************/ 11 12 13 /**************************************************************************/ 14 /**************************************************************************/ 15 /** */ 16 /** NetX Component */ 17 /** */ 18 /** Transmission Control Protocol (TCP) */ 19 /** */ 20 /**************************************************************************/ 21 /**************************************************************************/ 22 23 #define NX_SOURCE_CODE 24 25 26 /* Include necessary system files. */ 27 28 #include "nx_api.h" 29 #include "nx_tcp.h" 30 #include "nx_packet.h" 31 32 33 /**************************************************************************/ 34 /* */ 35 /* FUNCTION RELEASE */ 36 /* */ 37 /* _nx_tcp_socket_bytes_available PORTABLE C */ 38 /* 6.1 */ 39 /* AUTHOR */ 40 /* */ 41 /* Yuxin Zhou, Microsoft Corporation */ 42 /* */ 43 /* DESCRIPTION */ 44 /* */ 45 /* This function determines the number of bytes available on a TCP */ 46 /* socket for reception. */ 47 /* */ 48 /* INPUT */ 49 /* */ 50 /* socket_ptr Pointer to the TCP sockete */ 51 /* bytes_available Number of bytes returned to */ 52 /* the caller. */ 53 /* */ 54 /* OUTPUT */ 55 /* */ 56 /* status Completion status */ 57 /* */ 58 /* CALLS */ 59 /* */ 60 /* tx_mutex_get Obtain protection */ 61 /* tx_mutex_put Release protection */ 62 /* */ 63 /* CALLED BY */ 64 /* */ 65 /* Application Code */ 66 /* */ 67 /* RELEASE HISTORY */ 68 /* */ 69 /* DATE NAME DESCRIPTION */ 70 /* */ 71 /* 05-19-2020 Yuxin Zhou Initial Version 6.0 */ 72 /* 09-30-2020 Yuxin Zhou Modified comment(s), */ 73 /* resulting in version 6.1 */ 74 /* */ 75 /**************************************************************************/ _nx_tcp_socket_bytes_available(NX_TCP_SOCKET * socket_ptr,ULONG * bytes_available)76UINT _nx_tcp_socket_bytes_available(NX_TCP_SOCKET *socket_ptr, ULONG *bytes_available) 77 { 78 NX_IP *ip_ptr; 79 NX_PACKET *packet_ptr; 80 UINT data_size; 81 NX_TCP_HEADER *header_ptr; 82 UINT header_length; 83 INT done = 0; 84 85 /* Setup IP pointer. */ 86 ip_ptr = socket_ptr -> nx_tcp_socket_ip_ptr; 87 88 /* Obtain the IP mutex so we can examine the bound port. */ 89 tx_mutex_get(&(ip_ptr -> nx_ip_protection), TX_WAIT_FOREVER); 90 91 *bytes_available = 0; 92 93 94 /* Make sure the TCP connection has been established. */ 95 if ((socket_ptr -> nx_tcp_socket_state <= NX_TCP_LISTEN_STATE) || 96 (socket_ptr -> nx_tcp_socket_state > NX_TCP_ESTABLISHED)) 97 { 98 /* Release protection. */ 99 tx_mutex_put(&(ip_ptr -> nx_ip_protection)); 100 101 return(NX_NOT_CONNECTED); 102 } 103 104 packet_ptr = socket_ptr -> nx_tcp_socket_receive_queue_head; 105 106 if (packet_ptr == NX_NULL) 107 { 108 109 /* The receive queue is empty. */ 110 /* Release protection. */ 111 tx_mutex_put(&(ip_ptr -> nx_ip_protection)); 112 113 return(NX_SUCCESS); 114 } 115 116 /* Loop through all the packets on the queue and find out the total 117 number of bytes in the rx queue that are available to the applciation. */ 118 do 119 { 120 /*lint -e{923} suppress cast of ULONG to pointer. */ 121 if (packet_ptr -> nx_packet_queue_next == ((NX_PACKET *)NX_PACKET_READY)) 122 { 123 124 /* Compute the size of TCP payload in this packet */ 125 /*lint -e{927} -e{826} suppress cast of pointer to pointer, since it is necessary */ 126 header_ptr = (NX_TCP_HEADER *)packet_ptr -> nx_packet_prepend_ptr; 127 128 /* Calculate the header size for this packet. */ 129 header_length = (UINT)((header_ptr -> nx_tcp_header_word_3 >> NX_TCP_HEADER_SHIFT) * sizeof(ULONG)); 130 131 data_size = (UINT)(packet_ptr -> nx_packet_length - header_length); 132 *bytes_available += data_size; 133 134 if (packet_ptr == socket_ptr -> nx_tcp_socket_receive_queue_tail) 135 { 136 /* Already reached the last packet. */ 137 done = 1; 138 } 139 else 140 { 141 /* Move on to the next packet. */ 142 packet_ptr = packet_ptr -> nx_packet_union_next.nx_packet_tcp_queue_next; 143 } 144 } 145 else 146 { 147 /* If the packet has not been acked yet, then just return the 148 amount of bytes available so far. */ 149 done = 1; 150 } 151 } while (!done); 152 153 /* Release protection. */ 154 tx_mutex_put(&(ip_ptr -> nx_ip_protection)); 155 156 return(NX_SUCCESS); 157 } 158 159
