RTCS Connect

[handychandra]

Hi,

I want to ask about the long timeout of RTCS Connect() function. I want to know is there any way for RTCS Connect() to return directly if it failed to connect ? Because i read that the function will return after timeout, and the minimum timeout for that is 3 mins.

[David_Wu]

I have another issue regarding to connect() in MQX 4.0 (seemed same in MQX 4.1) - the issue is:

- the connect timeout in 382 seconds - I did not use OPT_CONNECT_TIMEOUT in my code

- the TCP packet is sent, then received an ICMP destination unreachable message which is handled in ICMP_service() and then discarded -

      - Why MQX did not sent to some routine in TCP family then send error back to wake up connect() function,  instead it keeps sending TCP SYN message in the sequences - 1s, 4s, 10s, 22s, 46s, 94s, 190s, 382s.

      - Is there a fix for this misbehavior? I am lost while trying to find a solution.

David

[danielchen · Accepted solution]

Hi Handy

The RTCS setsockopt() API permits the application to set the OPT_CONNECT_TIMEOUT option on a stream socket, which indicates the timeout (in millisec.) when a call to the connect API using that socket will return indicating a connection time-out error.

The RTCS User's Guide appears to indicate the value specified for the OPT_CONNECT_TIMEOUT option is to be >= 180000 msec.

You can change TCP_SENDTIMEOUT_MIN (tcp_prv.h) to your expected value

#define TCP_SENDTIMEOUT_MIN   100000L  /* as per RFC1122 4.2.3.5 */

But it is not recommended, because it violates the RFC1122

Have a great day,
Daniel

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