How to port MQTT of AWS IoT Device SDK for Embedded C to mangOH platform

Cloud & Connectivity
1

I am trying to integrate MQTT stack of AWS IoT Device SDK into my mangOH red board.

I downloaded latest SDK here:

and manage to make it work on local PC (Ubuntu 18.04 ) i.e. it can do mutual TLS authentication and simple MQTT publish to AWS IoT core cloud.

However when I tried to port over to mangOH platform, I made some progress but was stuck at compilation error which seemed from openssl library integration, it could not find function which was defined in this inclusion:

#include <openssl/ssl.h>

This mean, this library was recognized locally by my local PC OS but not by legato (release 16 ver 19.11.2). This is the snippet of compilation error:

<project_base>/cloud/aws/sdk/platform/posix/transport/src/openssl_posix.c:247:17: error: implicit declaration of function ‘SSL_set1_host’; did you mean ‘SSL_set_trust’? [-Werror=implicit-function-declaration]
sslStatus = SSL_set1_host( pOpensslParams->pSsl, pServerInfo->pHostName );
^~~~~~~~~~~~~
SSL_set_trust
<project_base>/cloud/aws/sdk/platform/posix/transport/src/openssl_posix.c: In function ‘setOptionalConfigurations’:
/home/iotlab0035x1804/repo/gatewayx/src/gateway/cloud/aws/sdk/platform/posix/transport/src/openssl_posix.c:533:13: error: implicit declaration of function ‘SSL_set_default_read_buffer_len’; did you mean ‘SSL_CTX_set_default_read_ahead’? [-Werror=implicit-function-declaration]
SSL_set_default_read_buffer_len( pSsl, ( size_t ) readBufferLength );
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
SSL_CTX_set_default_read_ahead
<project_base>/cloud/aws/sdk/platform/posix/transport/src/openssl_posix.c: In function ‘Openssl_Connect’:
<project_base>/cloud/aws/sdk/platform/posix/transport/src/openssl_posix.c:625:36: error: implicit declaration of function ‘TLS_client_method’; did you mean ‘DTLS_client_method’? [-Werror=implicit-function-declaration]
pSslContext = SSL_CTX_new( TLS_client_method() );
^~~~~~~~~~~~~~~~~
DTLS_client_method
<project_base>/src/gateway/cloud/aws/sdk/platform/posix/transport/src/openssl_posix.c:625:36: error: passing argument 1 of ‘SSL_CTX_new’ makes pointer from integer without a cast [-Werror=int-conversion]
In file included from <project_base>/src/gateway/cloud/aws/sdk/platform/posix/transport/include/openssl_posix.h:59:0,
from <project_base>/gatewayx/src/gateway/cloud/aws/sdk/platform/posix/transport/src/openssl_posix.c:35:
<project_base>/gatewayx/leaf-data/r16/wp76-toolchain/sysroots/armv7a-neon-poky-linux-gnueabi/usr/include/openssl/ssl.h:2131:10: note: expected ‘const SSL_METHOD * {aka const struct ssl_method_st *}’ but argument is of type ‘int’
SSL_CTX *SSL_CTX_new(const SSL_METHOD *meth);
^~~~~~~~~~~

This is snippet of my .cdef
cxxflags: {
-std=c++1z
-DMQTT_DO_NOT_USE_CUSTOM_CONFIG
-DDISABLE_LOGGING
-DLIBRARY_LOG_LEVEL=LOG_NONE
-I$CURDIR/cloud/aws/sdk/libraries/standard/coreMQTT/source/include
-I$CURDIR/cloud/aws/sdk/libraries/standard/coreMQTT/source/
-I$CURDIR/cloud/aws/sdk/libraries/standard/coreMQTT/source/interface
-I$CURDIR/cloud/aws/sdk/platform/posix/transport/include
-I$CURDIR/cloud/aws/logging-stack
-I$CURDIR/cloud/aws/sdk/platform/include
-I$CURDIR/cloud/aws/sdk/platform/posix/transport/include
}

cflags: {
-std=c99
-DMQTT_DO_NOT_USE_CUSTOM_CONFIG
-DDISABLE_LOGGING
-DLIBRARY_LOG_LEVEL=LOG_NONE
-I$CURDIR/cloud/aws/sdk/libraries/standard/coreMQTT/source/include
-I$CURDIR/cloud/aws/sdk/libraries/standard/coreMQTT/source/
-I$CURDIR/cloud/aws/sdk/libraries/standard/coreMQTT/source/interface
-I$CURDIR/cloud/aws/sdk/platform/posix/transport/include
-I$CURDIR/cloud/aws/logging-stack
-I$CURDIR/cloud/aws/sdk/platform/include
-I$CURDIR/cloud/aws/sdk/platform/posix/transport/include
}

provides: {
api: {
ipcGateway = $CURDIR/…/leipc/ipcGateway.api
}
}

sources: {
…

// AWS MQTT library
$CURDIR/cloud/aws/sdk/libraries/standard/coreMQTT/source/core_mqtt.c
$CURDIR/cloud/aws/sdk/libraries/standard/coreMQTT/source/core_mqtt_state.c
$CURDIR/cloud/aws/sdk/libraries/standard/coreMQTT/source/core_mqtt_serializer.c

$CURDIR/cloud/aws/sdk/platform/posix/transport/src/openssl_posix.c

}

2

Is it same issue as this one?

3

Thanks but It’s not.

4

https://www.openssl.org/docs/manmaster/man3/SSL_set_default_read_buffer_len.html

what is your “openssl version” on module?

You might also see here:

5

Why would ssl version matter? This is compile error.

Thanks for the link, but not that relevant.

6

Maybe only new version of ssl lib have that function

7

I see, the version is ssl 1.0.2 , the one associated with release 16:

root@swi-mdm9x28-wp:~# openssl version
OpenSSL 1.0.2p 14 Aug 2018

8

Ok, I read again AWS SDK, it needs openssl 1.1.0 or later.
This explains why the AWS SDK MQTT can’t be integrated to Legato release 16.

How should I go about this? Any legato release includes updated openssl?

If I were to add manually, how should I do it? How can I write the component def (i.e. cdef)

9

Probably you need to wait for next release r17

Or you can see here

To include in .cdef file: