[lwip-users] lwip_send() fails if sending to much data.

[Joel Pålsson]

Hi,

 

I’m trying to use the LWIP socket interface. I found one issue with lwip_send(). Normally socket send() calls returns the number of sent bytes which can be less than the number requested to be sent.

 

In non-blocking mode it seems as lwip_send() returns an error if requested to send more data than it can handle instead of sending the number of bytes it can.

 

My proposal is that the following code:

 

if ((flags & MSG_DONTWAIT) || netconn_is_nonblocking(sock->conn)) {

    if ((size > TCP_SND_BUF) || ((size / TCP_MSS) > TCP_SND_QUEUELEN)) {

      /* too much data to ever send nonblocking! */

      sock_set_errno(sock, EMSGSIZE);

      return -1;

    }

  }

 

should be changed to:

 

if ((flags & MSG_DONTWAIT) || netconn_is_nonblocking(sock->conn)) {

    if (size > TCP_SND_BUF) {

      size = TCP_SND_BUF;

    }

    if ((size / TCP_MSS) > TCP_SND_QUEUELEN) {

      size = TCP_MSS * TCP_SND_QUEUELEN;

    }

  }

 

What is your opinion about this?

 

Best Regards

Joel Pålsson