Use CI-CD-Github-Actions for spelling and formatting, add in the bot formatting action, update the CI-CD workflow files. Fix incorrect spelling and formatting on files. (#1083)

* Use new version of CI-CD Actions, checkout@v3 instead of checkout@v2 on all jobs * Use cSpell spell check, and use ubuntu-20.04 for formatting check * Add in bot formatting action * Update freertos_demo.yml and freertos_plus_demo.yml files to increase github log readability * Add in a Qemu demo onto the workflows.
2025-12-16 18:08:11 +08:00 · 2023-09-06 15:35:37 -04:00
parent 537007d96c
commit 3a2f6646f0
1036 changed files with 134568 additions and 127281 deletions
--- a/FreeRTOS-Plus/Source/Application-Protocols/network_transport/mbedtls_bio_tcp_sockets_wrapper.c
+++ b/FreeRTOS-Plus/Source/Application-Protocols/network_transport/mbedtls_bio_tcp_sockets_wrapper.c
@@ -1,6 +1,6 @@
 /*
 * FreeRTOS V202212.00
- * Copyright (C) 2020 Amazon.com, Inc. or its affiliates.  All Rights Reserved.
+ * Copyright (C) 2020 Amazon.com, Inc. or its affiliates. All Rights Reserved.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy of
 * this software and associated documentation files (the "Software"), to deal in
--- a/FreeRTOS-Plus/Source/Application-Protocols/network_transport/mbedtls_bio_tcp_sockets_wrapper.h
+++ b/FreeRTOS-Plus/Source/Application-Protocols/network_transport/mbedtls_bio_tcp_sockets_wrapper.h
@@ -1,6 +1,6 @@
 /*
 * FreeRTOS V202212.00
- * Copyright (C) 2020 Amazon.com, Inc. or its affiliates.  All Rights Reserved.
+ * Copyright (C) 2020 Amazon.com, Inc. or its affiliates. All Rights Reserved.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy of
 * this software and associated documentation files (the "Software"), to deal in
--- a/FreeRTOS-Plus/Source/Application-Protocols/network_transport/mbedtls_pk_pkcs11.c
+++ b/FreeRTOS-Plus/Source/Application-Protocols/network_transport/mbedtls_pk_pkcs11.c
@@ -1,6 +1,6 @@
 /*
 * FreeRTOS V202212.00
- * Copyright (C) 2020 Amazon.com, Inc. or its affiliates.  All Rights Reserved.
+ * Copyright (C) 2020 Amazon.com, Inc. or its affiliates. All Rights Reserved.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy of
 * this software and associated documentation files (the "Software"), to deal in
--- a/FreeRTOS-Plus/Source/Application-Protocols/network_transport/mbedtls_pkcs11.h
+++ b/FreeRTOS-Plus/Source/Application-Protocols/network_transport/mbedtls_pkcs11.h
@@ -1,6 +1,6 @@
 /*
 * FreeRTOS V202212.00
- * Copyright (C) 2020 Amazon.com, Inc. or its affiliates.  All Rights Reserved.
+ * Copyright (C) 2020 Amazon.com, Inc. or its affiliates. All Rights Reserved.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy of
 * this software and associated documentation files (the "Software"), to deal in
--- a/FreeRTOS-Plus/Source/Application-Protocols/network_transport/mbedtls_rng_pkcs11.c
+++ b/FreeRTOS-Plus/Source/Application-Protocols/network_transport/mbedtls_rng_pkcs11.c
@@ -1,6 +1,6 @@
 /*
 * FreeRTOS V202212.00
- * Copyright (C) 2020 Amazon.com, Inc. or its affiliates.  All Rights Reserved.
+ * Copyright (C) 2020 Amazon.com, Inc. or its affiliates. All Rights Reserved.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy of
 * this software and associated documentation files (the "Software"), to deal in
--- a/FreeRTOS-Plus/Source/Application-Protocols/network_transport/tcp_sockets_wrapper/include/tcp_sockets_wrapper.h
+++ b/FreeRTOS-Plus/Source/Application-Protocols/network_transport/tcp_sockets_wrapper/include/tcp_sockets_wrapper.h
@@ -1,6 +1,6 @@
 /*
 * FreeRTOS V202212.00
- * Copyright (C) 2020 Amazon.com, Inc. or its affiliates.  All Rights Reserved.
+ * Copyright (C) 2020 Amazon.com, Inc. or its affiliates. All Rights Reserved.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy of
 * this software and associated documentation files (the "Software"), to deal in
--- a/FreeRTOS-Plus/Source/Application-Protocols/network_transport/tcp_sockets_wrapper/ports/cellular/tcp_sockets_wrapper.c
+++ b/FreeRTOS-Plus/Source/Application-Protocols/network_transport/tcp_sockets_wrapper/ports/cellular/tcp_sockets_wrapper.c
@@ -1,6 +1,6 @@
 /*
 * FreeRTOS V202212.00
- * Copyright (C) 2020 Amazon.com, Inc. or its affiliates.  All Rights Reserved.
+ * Copyright (C) 2020 Amazon.com, Inc. or its affiliates. All Rights Reserved.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy of
 * this software and associated documentation files (the "Software"), to deal in
@@ -538,7 +538,7 @@ static BaseType_t prvCellularSocketRegisterCallback( CellularSocketHandle_t cell

        if( socketStatus != CELLULAR_SUCCESS )
        {
-            LogError( ( "Failed to SocketRegisterSocketOpenCallbac. Socket status %d.", socketStatus ) );
+            LogError( ( "Failed to SocketRegisterSocketOpenCallback. Socket status %d.", socketStatus ) );
            retRegCallback = TCP_SOCKETS_ERRNO_ERROR;
        }
    }
--- a/FreeRTOS-Plus/Source/Application-Protocols/network_transport/tcp_sockets_wrapper/ports/freertos_plus_tcp/sockets_wrapper.c
+++ b/FreeRTOS-Plus/Source/Application-Protocols/network_transport/tcp_sockets_wrapper/ports/freertos_plus_tcp/sockets_wrapper.c
@@ -1,6 +1,6 @@
 /*
 * FreeRTOS V202212.00
- * Copyright (C) 2020 Amazon.com, Inc. or its affiliates.  All Rights Reserved.
+ * Copyright (C) 2020 Amazon.com, Inc. or its affiliates. All Rights Reserved.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy of
 * this software and associated documentation files (the "Software"), to deal in
@@ -93,15 +93,17 @@ BaseType_t Sockets_Connect( Socket_t * pTcpSocket,
        serverAddress.sin_port = FreeRTOS_htons( port );
        serverAddress.sin_len = ( uint8_t ) sizeof( serverAddress );

-    #if defined( ipconfigIPv4_BACKWARD_COMPATIBLE ) && ( ipconfigIPv4_BACKWARD_COMPATIBLE == 0 )
-        serverAddress.sin_address.ulIP_IPv4 = ( uint32_t ) FreeRTOS_gethostbyname( pHostName );
-        /* Check for errors from DNS lookup. */
-        if( serverAddress.sin_address.ulIP_IPv4 == 0U )
-    #else
-        serverAddress.sin_addr = ( uint32_t ) FreeRTOS_gethostbyname( pHostName );
-        /* Check for errors from DNS lookup. */
-        if( serverAddress.sin_addr == 0U )
-    #endif /* defined( ipconfigIPv4_BACKWARD_COMPATIBLE ) && ( ipconfigIPv4_BACKWARD_COMPATIBLE == 0 ) */
+        #if defined( ipconfigIPv4_BACKWARD_COMPATIBLE ) && ( ipconfigIPv4_BACKWARD_COMPATIBLE == 0 )
+            serverAddress.sin_address.ulIP_IPv4 = ( uint32_t ) FreeRTOS_gethostbyname( pHostName );
+
+            /* Check for errors from DNS lookup. */
+            if( serverAddress.sin_address.ulIP_IPv4 == 0U )
+        #else
+            serverAddress.sin_addr = ( uint32_t ) FreeRTOS_gethostbyname( pHostName );
+
+            /* Check for errors from DNS lookup. */
+            if( serverAddress.sin_addr == 0U )
+        #endif /* defined( ipconfigIPv4_BACKWARD_COMPATIBLE ) && ( ipconfigIPv4_BACKWARD_COMPATIBLE == 0 ) */

        {
            LogError( ( "Failed to connect to server: DNS resolution failed: Hostname=%s.",
--- a/FreeRTOS-Plus/Source/Application-Protocols/network_transport/tcp_sockets_wrapper/ports/freertos_plus_tcp/sockets_wrapper.h
+++ b/FreeRTOS-Plus/Source/Application-Protocols/network_transport/tcp_sockets_wrapper/ports/freertos_plus_tcp/sockets_wrapper.h
@@ -1,6 +1,6 @@
 /*
 * FreeRTOS V202212.00
- * Copyright (C) 2020 Amazon.com, Inc. or its affiliates.  All Rights Reserved.
+ * Copyright (C) 2020 Amazon.com, Inc. or its affiliates. All Rights Reserved.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy of
 * this software and associated documentation files (the "Software"), to deal in
@@ -37,7 +37,7 @@
 #include "FreeRTOS_Sockets.h"
 #include "FreeRTOS_DNS.h"

-#define SOCKETS_INVALID_SOCKET      ( ( Socket_t ) ~0U )
+#define SOCKETS_INVALID_SOCKET    ( ( Socket_t ) ~0U )

 /**
 * @brief Establish a connection to server.
--- a/FreeRTOS-Plus/Source/Application-Protocols/network_transport/tcp_sockets_wrapper/ports/freertos_plus_tcp/tcp_sockets_wrapper.c
+++ b/FreeRTOS-Plus/Source/Application-Protocols/network_transport/tcp_sockets_wrapper/ports/freertos_plus_tcp/tcp_sockets_wrapper.c
@@ -1,6 +1,6 @@
 /*
 * FreeRTOS V202212.00
- * Copyright (C) 2020 Amazon.com, Inc. or its affiliates.  All Rights Reserved.
+ * Copyright (C) 2020 Amazon.com, Inc. or its affiliates. All Rights Reserved.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy of
 * this software and associated documentation files (the "Software"), to deal in
@@ -117,15 +117,17 @@ BaseType_t TCP_Sockets_Connect( Socket_t * pTcpSocket,
        serverAddress.sin_port = FreeRTOS_htons( port );
        serverAddress.sin_len = ( uint8_t ) sizeof( serverAddress );

-#if defined( ipconfigIPv4_BACKWARD_COMPATIBLE ) && ( ipconfigIPv4_BACKWARD_COMPATIBLE == 0 )
-        serverAddress.sin_address.ulIP_IPv4 = ( uint32_t ) FreeRTOS_gethostbyname( pHostName );
-        /* Check for errors from DNS lookup. */
-        if( serverAddress.sin_address.ulIP_IPv4 == 0U )
-#else
-        serverAddress.sin_addr = ( uint32_t ) FreeRTOS_gethostbyname( pHostName );
-        /* Check for errors from DNS lookup. */
-        if( serverAddress.sin_addr == 0U )
-#endif /* defined( ipconfigIPv4_BACKWARD_COMPATIBLE ) && ( ipconfigIPv4_BACKWARD_COMPATIBLE == 0 ) */
+        #if defined( ipconfigIPv4_BACKWARD_COMPATIBLE ) && ( ipconfigIPv4_BACKWARD_COMPATIBLE == 0 )
+            serverAddress.sin_address.ulIP_IPv4 = ( uint32_t ) FreeRTOS_gethostbyname( pHostName );
+
+            /* Check for errors from DNS lookup. */
+            if( serverAddress.sin_address.ulIP_IPv4 == 0U )
+        #else
+            serverAddress.sin_addr = ( uint32_t ) FreeRTOS_gethostbyname( pHostName );
+
+            /* Check for errors from DNS lookup. */
+            if( serverAddress.sin_addr == 0U )
+        #endif /* defined( ipconfigIPv4_BACKWARD_COMPATIBLE ) && ( ipconfigIPv4_BACKWARD_COMPATIBLE == 0 ) */

        {
            LogError( ( "Failed to connect to server: DNS resolution failed: Hostname=%s.",
--- a/FreeRTOS-Plus/Source/Application-Protocols/network_transport/transport_mbedtls.c
+++ b/FreeRTOS-Plus/Source/Application-Protocols/network_transport/transport_mbedtls.c
@@ -1,6 +1,6 @@
 /*
 * FreeRTOS V202212.00
- * Copyright (C) 2020 Amazon.com, Inc. or its affiliates.  All Rights Reserved.
+ * Copyright (C) 2020 Amazon.com, Inc. or its affiliates. All Rights Reserved.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy of
 * this software and associated documentation files (the "Software"), to deal in
@@ -210,12 +210,12 @@ static TlsTransportStatus_t tlsHandshake( NetworkContext_t * pNetworkContext,
 * @brief Initialize mbedTLS.
 *
 * @param[out] entropyContext mbed TLS entropy context for generation of random numbers.
- * @param[out] ctrDrgbContext mbed TLS CTR DRBG context for generation of random numbers.
+ * @param[out] ctrDrbgContext mbed TLS CTR DRBG context for generation of random numbers.
 *
 * @return #TLS_TRANSPORT_SUCCESS, or #TLS_TRANSPORT_INTERNAL_ERROR.
 */
 static TlsTransportStatus_t initMbedtls( mbedtls_entropy_context * pEntropyContext,
-                                         mbedtls_ctr_drbg_context * pCtrDrgbContext );
+                                         mbedtls_ctr_drbg_context * pCtrDrbgContext );

 /*-----------------------------------------------------------*/

@@ -240,7 +240,7 @@ static void sslContextFree( SSLContext_t * pSslContext )
    mbedtls_x509_crt_free( &( pSslContext->clientCert ) );
    mbedtls_pk_free( &( pSslContext->privKey ) );
    mbedtls_entropy_free( &( pSslContext->entropyContext ) );
-    mbedtls_ctr_drbg_free( &( pSslContext->ctrDrgbContext ) );
+    mbedtls_ctr_drbg_free( &( pSslContext->ctrDrbgContext ) );
    mbedtls_ssl_config_free( &( pSslContext->config ) );
 }
 /*-----------------------------------------------------------*/
@@ -321,7 +321,7 @@ static int32_t setPrivateKey( SSLContext_t * pSslContext,
                                             privateKeySize,
                                             NULL, 0,
                                             mbedtls_ctr_drbg_random,
-                                             &( pSslContext->ctrDrgbContext ) );
+                                             &( pSslContext->ctrDrbgContext ) );
    #endif /* if MBEDTLS_VERSION_NUMBER < 0x03000000 */

    if( mbedtlsError != 0 )
@@ -351,7 +351,7 @@ static int32_t setCredentials( SSLContext_t * pSslContext,
                               MBEDTLS_SSL_VERIFY_REQUIRED );
    mbedtls_ssl_conf_rng( &( pSslContext->config ),
                          mbedtls_ctr_drbg_random,
-                          &( pSslContext->ctrDrgbContext ) );
+                          &( pSslContext->ctrDrbgContext ) );
    mbedtls_ssl_conf_cert_profile( &( pSslContext->config ),
                                   &( pSslContext->certProfile ) );

@@ -429,6 +429,7 @@ static void setOptionalConfigurations( SSLContext_t * pSslContext,

    /* Set Maximum Fragment Length if enabled. */
    #ifdef MBEDTLS_SSL_MAX_FRAGMENT_LENGTH
+
        /* Enable the max fragment extension. 4096 bytes is currently the largest fragment size permitted.
         * See RFC 8449 https://tools.ietf.org/html/rfc8449 for more information.
         *
@@ -574,7 +575,7 @@ static TlsTransportStatus_t tlsHandshake( NetworkContext_t * pNetworkContext,
 /*-----------------------------------------------------------*/

 static TlsTransportStatus_t initMbedtls( mbedtls_entropy_context * pEntropyContext,
-                                         mbedtls_ctr_drbg_context * pCtrDrgbContext )
+                                         mbedtls_ctr_drbg_context * pCtrDrbgContext )
 {
    TlsTransportStatus_t returnStatus = TLS_TRANSPORT_SUCCESS;
    int32_t mbedtlsError = 0;
@@ -586,7 +587,7 @@ static TlsTransportStatus_t initMbedtls( mbedtls_entropy_context * pEntropyConte

    /* Initialize contexts for random number generation. */
    mbedtls_entropy_init( pEntropyContext );
-    mbedtls_ctr_drbg_init( pCtrDrgbContext );
+    mbedtls_ctr_drbg_init( pCtrDrbgContext );

    if( mbedtlsError != 0 )
    {
@@ -599,7 +600,7 @@ static TlsTransportStatus_t initMbedtls( mbedtls_entropy_context * pEntropyConte
    if( returnStatus == TLS_TRANSPORT_SUCCESS )
    {
        /* Seed the random number generator. */
-        mbedtlsError = mbedtls_ctr_drbg_seed( pCtrDrgbContext,
+        mbedtlsError = mbedtls_ctr_drbg_seed( pCtrDrbgContext,
                                              mbedtls_entropy_func,
                                              pEntropyContext,
                                              NULL,
@@ -686,7 +687,7 @@ TlsTransportStatus_t TLS_FreeRTOS_Connect( NetworkContext_t * pNetworkContext,
        isSocketConnected = pdTRUE;

        returnStatus = initMbedtls( &( pTlsTransportParams->sslContext.entropyContext ),
-                                    &( pTlsTransportParams->sslContext.ctrDrgbContext ) );
+                                    &( pTlsTransportParams->sslContext.ctrDrbgContext ) );
    }

    /* Initialize TLS contexts and set credentials. */
--- a/FreeRTOS-Plus/Source/Application-Protocols/network_transport/transport_mbedtls.h
+++ b/FreeRTOS-Plus/Source/Application-Protocols/network_transport/transport_mbedtls.h
@@ -1,6 +1,6 @@
 /*
 * FreeRTOS V202212.00
- * Copyright (C) 2020 Amazon.com, Inc. or its affiliates.  All Rights Reserved.
+ * Copyright (C) 2020 Amazon.com, Inc. or its affiliates. All Rights Reserved.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy of
 * this software and associated documentation files (the "Software"), to deal in
@@ -97,7 +97,7 @@ typedef struct SSLContext
    mbedtls_x509_crt clientCert;             /**< @brief Client certificate context. */
    mbedtls_pk_context privKey;              /**< @brief Client private key context. */
    mbedtls_entropy_context entropyContext;  /**< @brief Entropy context for random number generation. */
-    mbedtls_ctr_drbg_context ctrDrgbContext; /**< @brief CTR DRBG context for random number generation. */
+    mbedtls_ctr_drbg_context ctrDrbgContext; /**< @brief CTR DRBG context for random number generation. */
 } SSLContext_t;

 /**
--- a/FreeRTOS-Plus/Source/Application-Protocols/network_transport/transport_mbedtls_pkcs11.c
+++ b/FreeRTOS-Plus/Source/Application-Protocols/network_transport/transport_mbedtls_pkcs11.c
@@ -1,6 +1,6 @@
 /*
 * FreeRTOS V202212.00
- * Copyright (C) 2020 Amazon.com, Inc. or its affiliates.  All Rights Reserved.
+ * Copyright (C) 2020 Amazon.com, Inc. or its affiliates. All Rights Reserved.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy of
 * this software and associated documentation files (the "Software"), to deal in
--- a/FreeRTOS-Plus/Source/Application-Protocols/network_transport/transport_mbedtls_pkcs11.h
+++ b/FreeRTOS-Plus/Source/Application-Protocols/network_transport/transport_mbedtls_pkcs11.h
@@ -1,6 +1,6 @@
 /*
 * FreeRTOS V202212.00
- * Copyright (C) 2020 Amazon.com, Inc. or its affiliates.  All Rights Reserved.
+ * Copyright (C) 2020 Amazon.com, Inc. or its affiliates. All Rights Reserved.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy of
 * this software and associated documentation files (the "Software"), to deal in
--- a/FreeRTOS-Plus/Source/Application-Protocols/network_transport/transport_plaintext.c
+++ b/FreeRTOS-Plus/Source/Application-Protocols/network_transport/transport_plaintext.c
@@ -1,6 +1,6 @@
 /*
 * FreeRTOS V202212.00
- * Copyright (C) 2020 Amazon.com, Inc. or its affiliates.  All Rights Reserved.
+ * Copyright (C) 2020 Amazon.com, Inc. or its affiliates. All Rights Reserved.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy of
 * this software and associated documentation files (the "Software"), to deal in
--- a/FreeRTOS-Plus/Source/Application-Protocols/network_transport/transport_plaintext.h
+++ b/FreeRTOS-Plus/Source/Application-Protocols/network_transport/transport_plaintext.h
@@ -1,6 +1,6 @@
 /*
 * FreeRTOS V202212.00
- * Copyright (C) 2020 Amazon.com, Inc. or its affiliates.  All Rights Reserved.
+ * Copyright (C) 2020 Amazon.com, Inc. or its affiliates. All Rights Reserved.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy of
 * this software and associated documentation files (the "Software"), to deal in
@@ -118,7 +118,7 @@ PlaintextTransportStatus_t Plaintext_FreeRTOS_Disconnect( const NetworkContext_t

 /**
 * @brief Receives data from an established TCP connection.
- * 
+ *
 * @note When the number of bytes requested is 1, the TCP socket's Rx stream
 * is checked for available bytes to read. If there are none, this function
 * immediately returns 0 without blocking.
--- a/FreeRTOS-Plus/Source/Application-Protocols/network_transport/transport_wolfSSL.c
+++ b/FreeRTOS-Plus/Source/Application-Protocols/network_transport/transport_wolfSSL.c
@@ -1,6 +1,6 @@
 /*
 * FreeRTOS V202212.00
- * Copyright (C) 2020 Amazon.com, Inc. or its affiliates.  All Rights Reserved.
+ * Copyright (C) 2020 Amazon.com, Inc. or its affiliates. All Rights Reserved.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy of
 * this software and associated documentation files (the "Software"), to deal in
--- a/FreeRTOS-Plus/Source/Application-Protocols/network_transport/transport_wolfSSL.h
+++ b/FreeRTOS-Plus/Source/Application-Protocols/network_transport/transport_wolfSSL.h
@@ -1,6 +1,6 @@
 /*
 * FreeRTOS V202212.00
- * Copyright (C) 2020 Amazon.com, Inc. or its affiliates.  All Rights Reserved.
+ * Copyright (C) 2020 Amazon.com, Inc. or its affiliates. All Rights Reserved.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy of
 * this software and associated documentation files (the "Software"), to deal in
@@ -71,8 +71,8 @@
 */
 typedef struct SSLContext
 {
-    WOLFSSL_CTX* ctx;                     /**< @brief wolfSSL context */
-    WOLFSSL* ssl;                         /**< @brief wolfSSL ssl session context */
+    WOLFSSL_CTX * ctx; /**< @brief wolfSSL context */
+    WOLFSSL * ssl;     /**< @brief wolfSSL ssl session context */
 } SSLContext_t;

 /**
--- a/FreeRTOS-Plus/Source/Application-Protocols/readme.txt
+++ b/FreeRTOS-Plus/Source/Application-Protocols/readme.txt
@@ -6,10 +6,10 @@ the same transport interface definition.

 Directories:

-+ coreMQTT contains the implementation of the coreMQTT library. 
+ coreMQTT contains the implementation of the coreMQTT library.
 + coreMQTT-Agent contains the implementation of the coreMQTT Agent library.
 + coreHTTP contains the implementation of the coreHTTP library.
 + coreSNTP contains the implementation of the coreSNTP library.
-+ network_transport contains multiple implementations for the transport interface.   
+ network_transport contains multiple implementations for the transport interface.

 For more details on the above libraries, see: https://www.freertos.org/application-protocols.html.