1 /* 2 * FreeRTOS+TCP V3.1.0 3 * Copyright (C) 2022 Amazon.com, Inc. or its affiliates. All Rights Reserved. 4 * 5 * SPDX-License-Identifier: MIT 6 * 7 * Permission is hereby granted, free of charge, to any person obtaining a copy of 8 * this software and associated documentation files (the "Software"), to deal in 9 * the Software without restriction, including without limitation the rights to 10 * use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of 11 * the Software, and to permit persons to whom the Software is furnished to do so, 12 * subject to the following conditions: 13 * 14 * The above copyright notice and this permission notice shall be included in all 15 * copies or substantial portions of the Software. 16 * 17 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 18 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS 19 * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR 20 * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER 21 * IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN 22 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. 23 * 24 * http://aws.amazon.com/freertos 25 * http://www.FreeRTOS.org 26 */ 27 28 #ifndef FREERTOS_TCP_IP_H 29 #define FREERTOS_TCP_IP_H 30 31 /* *INDENT-OFF* */ 32 #ifdef __cplusplus 33 extern "C" { 34 #endif 35 /* *INDENT-ON* */ 36 37 BaseType_t xProcessReceivedTCPPacket( NetworkBufferDescriptor_t * pxDescriptor ); 38 39 typedef enum eTCP_STATE 40 { 41 /* Comments about the TCP states are borrowed from the very useful 42 * Wiki page: 43 * http://en.wikipedia.org/wiki/Transmission_Control_Protocol */ 44 eCLOSED = 0U, /* 0 (server + client) no connection state at all. */ 45 eTCP_LISTEN, /* 1 (server) waiting for a connection request 46 * from any remote TCP and port. */ 47 eCONNECT_SYN, /* 2 (client) internal state: socket wants to send 48 * a connect */ 49 eSYN_FIRST, /* 3 (server) Just created, must ACK the SYN request. */ 50 eSYN_RECEIVED, /* 4 (server) waiting for a confirming connection request 51 * acknowledgement after having both received and sent a connection request. */ 52 eESTABLISHED, /* 5 (server + client) an open connection, data received can be 53 * delivered to the user. The normal state for the data transfer phase of the connection. */ 54 eFIN_WAIT_1, /* 6 (server + client) waiting for a connection termination request from the remote TCP, 55 * or an acknowledgement of the connection termination request previously sent. */ 56 eFIN_WAIT_2, /* 7 (server + client) waiting for a connection termination request from the remote TCP. */ 57 eCLOSE_WAIT, /* 8 (server + client) waiting for a connection termination request from the local user. */ 58 eCLOSING, /* 9 (server + client) waiting for a connection termination request acknowledgement from the remote TCP. */ 59 eLAST_ACK, /*10 (server + client) waiting for an acknowledgement of the connection termination request 60 * previously sent to the remote TCP 61 * (which includes an acknowledgement of its connection termination request). */ 62 eTIME_WAIT, /*11 (either server or client) waiting for enough time to pass to be sure the remote TCP received the 63 * acknowledgement of its connection termination request. [According to RFC 793 a connection can 64 * stay in TIME-WAIT for a maximum of four minutes known as a MSL (maximum segment lifetime).] */ 65 } eIPTCPState_t; 66 67 /* 68 * The meaning of the TCP flags: 69 */ 70 #define tcpTCP_FLAG_FIN ( ( uint8_t ) 0x01U ) /**< No more data from sender. */ 71 #define tcpTCP_FLAG_SYN ( ( uint8_t ) 0x02U ) /**< Synchronize sequence numbers. */ 72 #define tcpTCP_FLAG_RST ( ( uint8_t ) 0x04U ) /**< Reset the connection. */ 73 #define tcpTCP_FLAG_PSH ( ( uint8_t ) 0x08U ) /**< Push function: please push buffered data to the recv application. */ 74 #define tcpTCP_FLAG_ACK ( ( uint8_t ) 0x10U ) /**< Acknowledgment field is significant. */ 75 #define tcpTCP_FLAG_URG ( ( uint8_t ) 0x20U ) /**< Urgent pointer field is significant. */ 76 #define tcpTCP_FLAG_ECN ( ( uint8_t ) 0x40U ) /**< ECN-Echo. */ 77 #define tcpTCP_FLAG_CWR ( ( uint8_t ) 0x80U ) /**< Congestion Window Reduced. */ 78 79 #define tcpTCP_FLAG_CTRL ( ( uint8_t ) 0x1FU ) /**< A mask to filter all protocol flags. */ 80 81 82 /* 83 * A few values of the TCP options: 84 */ 85 #define tcpTCP_OPT_END 0U /**< End of TCP options list. */ 86 #define tcpTCP_OPT_NOOP 1U /**< "No-operation" TCP option. */ 87 #define tcpTCP_OPT_MSS 2U /**< Maximum segment size TCP option. */ 88 #define tcpTCP_OPT_WSOPT 3U /**< TCP Window Scale Option (3-byte long). */ 89 #define tcpTCP_OPT_SACK_P 4U /**< Advertise that SACK is permitted. */ 90 #define tcpTCP_OPT_SACK_A 5U /**< SACK option with first/last. */ 91 #define tcpTCP_OPT_TIMESTAMP 8U /**< Time-stamp option. */ 92 93 94 #define tcpTCP_OPT_MSS_LEN 4U /**< Length of TCP MSS option. */ 95 #define tcpTCP_OPT_WSOPT_LEN 3U /**< Length of TCP WSOPT option. */ 96 97 #define tcpTCP_OPT_TIMESTAMP_LEN 10 /**< fixed length of the time-stamp option. */ 98 99 /** @brief 100 * Minimum segment length as outlined by RFC 791 section 3.1. 101 * Minimum segment length ( 536 ) = Minimum MTU ( 576 ) - IP Header ( 20 ) - TCP Header ( 20 ). 102 */ 103 #define tcpMINIMUM_SEGMENT_LENGTH 536U 104 105 /** @brief 106 * The macro tcpNOW_CONNECTED() is use to determine if the connection makes a 107 * transition from connected to non-connected and vice versa. 108 * tcpNOW_CONNECTED() returns true when the status has one of these values: 109 * eESTABLISHED, eFIN_WAIT_1, eFIN_WAIT_2, eCLOSING, eLAST_ACK, eTIME_WAIT 110 * Technically the connection status is closed earlier, but the library wants 111 * to prevent that the socket will be deleted before the last ACK has been 112 * and thus causing a 'RST' packet on either side. 113 */ 114 #define tcpNOW_CONNECTED( status ) \ 115 ( ( ( ( status ) >= ( BaseType_t ) eESTABLISHED ) && ( ( status ) != ( BaseType_t ) eCLOSE_WAIT ) ) ? 1 : 0 ) 116 117 /** @brief 118 * The highest 4 bits in the TCP offset byte indicate the total length of the 119 * TCP header, divided by 4. 120 */ 121 #define tcpVALID_BITS_IN_TCP_OFFSET_BYTE ( 0xF0U ) 122 123 /* 124 * Acknowledgements to TCP data packets may be delayed as long as more is being expected. 125 * A normal delay would be 200ms. Here a much shorter delay of 20 ms is being used to 126 * gain performance. 127 */ 128 #define tcpDELAYED_ACK_SHORT_DELAY_MS ( 2 ) /**< Should not become smaller than 1. */ 129 #define tcpDELAYED_ACK_LONGER_DELAY_MS ( 20 ) /**< Longer delay for ACK. */ 130 131 132 /** @brief 133 * The MSS (Maximum Segment Size) will be taken as large as possible. However, packets with 134 * an MSS of 1460 bytes won't be transported through the internet. The MSS will be reduced 135 * to 1400 bytes. 136 */ 137 #define tcpREDUCED_MSS_THROUGH_INTERNET ( 1400 ) 138 139 /** @brief 140 * When there are no TCP options, the TCP offset equals 20 bytes, which is stored as 141 * the number 5 (words) in the higher nibble of the TCP-offset byte. 142 */ 143 #define tcpTCP_OFFSET_LENGTH_BITS ( 0xf0U ) 144 #define tcpTCP_OFFSET_STANDARD_LENGTH ( 0x50U ) /**< Standard TCP packet offset. */ 145 146 147 /** @brief 148 * Each TCP socket is checked regularly to see if it can send data packets. 149 * By default, the maximum number of packets sent during one check is limited to 8. 150 * This amount may be further limited by setting the socket's TX window size. 151 */ 152 #if ( !defined( SEND_REPEATED_COUNT ) ) 153 #define SEND_REPEATED_COUNT ( 8 ) 154 #endif /* !defined( SEND_REPEATED_COUNT ) */ 155 156 /** @brief 157 * Define a maximum period of time (ms) to leave a TCP-socket unattended. 158 * When a TCP timer expires, retries and keep-alive messages will be checked. 159 */ 160 #ifndef tcpMAXIMUM_TCP_WAKEUP_TIME_MS 161 #define tcpMAXIMUM_TCP_WAKEUP_TIME_MS 20000U 162 #endif 163 164 /* Two macro's that were introduced to work with both IPv4 and IPv6. */ 165 #define xIPHeaderSize( pxNetworkBuffer ) ( ipSIZE_OF_IPv4_HEADER ) /**< Size of IP Header. */ 166 #define uxIPHeaderSizeSocket( pxSocket ) ( ipSIZE_OF_IPv4_HEADER ) /**< Size of IP Header socket. */ 167 168 169 /* *INDENT-OFF* */ 170 #ifdef __cplusplus 171 } /* extern "C" */ 172 #endif 173 /* *INDENT-ON* */ 174 175 #endif /* FREERTOS_TCP_IP_H */ 176
