Hello,
I am using this example for the source of the my main purpose : https://github.com/straight-coding/LPC407x-NoOS-LWIP-MBEDTLS-HTTPD-KEIL/blob/f3943f7487a296a16ddff51885c9c8d0ca07562a/LambdaIOT/httpd/http_core.c
This example using https but I'm trying to use this example on Modbus Server on lwip-mbedtls-altcp-nonRTOS stm32.
This is init function for the server tcp connections:
BOOL
xMBTCPPortInit( USHORT usTCPPort )
{
struct altcp_pcb *pxPCBListenNew, *pxPCBListenOld;
BOOL bOkay = (BOOL)FALSE;
USHORT usPort;
extern struct altcp_tls_config* getTlsConfig(void);
tls_config = getTlsConfig();
mbedtls_ssl_conf_dbg(tls_config, my_debug, NULL);
mbedtls_debug_set_threshold(5);
if( usTCPPort == 0 )
{
usPort = MB_TCP_DEFAULT_PORT;
}
else
{
usPort = ( USHORT ) usTCPPort;
}
if( ( pxPCBListenNew = pxPCBListenOld = altcp_tls_new( tls_config,IPADDR_TYPE_ANY) ) == NULL )
{
/* Can't create TCP socket. */
bOkay = (BOOL)FALSE;
}
else
if( altcp_bind( pxPCBListenNew, IP_ANY_TYPE, ( u16_t ) usPort ) != ERR_OK )
{
/* Bind failed - Maybe illegal port value or in use. */
( void )altcp_close( pxPCBListenOld );
bOkay = (BOOL)FALSE;
}
else if( ( pxPCBListenNew = altcp_listen( pxPCBListenNew ) ) == NULL )
{
( void )altcp_close( pxPCBListenOld );
bOkay = (BOOL)FALSE;
}
else
{
// altcp_tls_new(pxPCBListenNew, IP_GET_TYPE(ip_addr))*/;
/* Register callback function for new clients. */
altcp_accept( pxPCBListenNew, prvxMBTCPPortAccept );
/* Everything okay. Set global variable. */
pxPCBListen = pxPCBListenNew;
#ifdef MB_TCP_DEBUG
vMBPortLog( MB_LOG_DEBUG, "MBTCP-ACCEPT", "Protocol stack ready.\r\n" );
#endif
SerialPrint("MBTCTP-ACCEPT");
}
bOkay = (BOOL)TRUE;
return bOkay;
}
struct altcp_tls_config* getTlsConfig(void)
{
struct altcp_tls_config* conf;
size_t privkey_len = strlen(privkey) + 1;
size_t privkey_pass_len = strlen(privkey_pass) + 1;
size_t cert_len = strlen(cert) + 1;
conf = altcp_tls_create_config_server_privkey_cert((u8_t*)privkey, privkey_len, (u8_t*)privkey_pass, privkey_pass_len, (u8_t*)cert, cert_len);
return conf;
}
And I am using basic python tls client example to show successful mbedtls handshake.
This is my client.py codes:
import time
from socket import create_connection
from ssl import SSLContext, PROTOCOL_TLS_CLIENT
import ssl
hostname='example.org'
ip = '192.168.1.2'
port = 502
context = SSLContext(PROTOCOL_TLS_CLIENT)
context.options |= ssl.OP_NO_SSLv3
context.options |= ssl.OP_NO_TLSv1
context.options |= ssl.OP_NO_TLSv1_1
context.load_verify_locations('cert.pem')
with create_connection((ip, port)) as client:
with context.wrap_socket(client, server_hostname=hostname) as tls:
print(f'Using {tls.version()}\n')
tls.sendall(b'Hello world')
data = "" style="color:rgb(104,151,187)">1024)
print(f'Server says: {data}')
When I try to start communication I get below outputs on wireshark:
When the server send hello message I've this error on the line:
When I checked the low_level_output functions I get sending data bytes 150 byte but Ipv4 length shows us 576 byte, opt.h file set as default but if I changed TCP_MSS as a 250 byte so I can send 136 byte and Ipv4 packet lenght shows me 136. But does not make sense. I couldnt do successful handshaking. Lwip takes care of the IP part if I send the another IP based packet (like icmp) packet with different sizes. I didnt get IPv4 packet length error.
I only have this error when I used mbedtls. How can I find the problem?My mbedtls debug outputs in this link https://paste.ofcode.org/PP3zFmrLcKqPdRMT3LzETz How cna I solve this problem ? What is the reason for the lenght problem ?
Best Regards.
Embeded System Engineer