Re: [lwip-users] lwip, mqtt and mbedtls

[Manu Abraham]

Hi,

After going through:

https://tls.mbed.org/kb/how-to/reduce-mbedtls-memory-and-storage-footprint

Did some tuning to the mbedtls lib by changing the following parameters:

#define MBEDTLS_MPI_WINDOW_SIZE            6
#define MBEDTLS_MPI_MAX_SIZE            1024
#define MBEDTLS_ECP_WINDOW_SIZE            2

#define MBEDTLS_SSL_MAX_CONTENT_LEN             2048
#define MBEDTLS_SSL_IN_CONTENT_LEN              2048
#define MBEDTLS_SSL_OUT_CONTENT_LEN             2048

With that change and with the default lwipopts:
#define MEM_SIZE                (10*1024)
#define MEMP_NUM_PBUF           10
#define MEMP_NUM_TCP_PCB        10
#define MEMP_NUM_TCP_PCB_LISTEN 5
#define MEMP_NUM_TCP_SEG        8

#define TCP_SND_BUF             (4*TCP_MSS)
#define TCP_SND_QUEUELEN        (2* TCP_SND_BUF/TCP_MSS)
#define TCP_WND                 (2*TCP_MSS)

altcp_mbedtls gets connected to a locally confgured mosquitto ..

 (152) mqtt_example_init: Connecting to MQTT Broker:192.168.1.34:8883
tcp_bind: bind to port 57804
mqtt_client_connect: Connecting to host: 192.168.1.34 at port:8883
tcp_connect to port 8883
tcp_recved: received 1460 bytes, wnd 2920 (0).
tcp_recved: received 945 bytes, wnd 2920 (0).


I do not see anything else (or the handshake for that) from altcp_mbedtls

At the mosquitto end of it, however I do get:

1598200852: New connection from 192.168.1.33 on port 8883.
1598200853: OpenSSL Error: error:1417C0C7:SSL routines:tls_process_client_certif
icate:peer did not return a certificate
1598200853: Socket error on client <unknown>, disconnecting.

Any thoughts or suggestions, on what's going on ?

Thanks,

Manu