Error in open_socket_out timeout code

[Joe Meadows]

Hello,

There is a bug in lib/util_sock.c:open_socket_out() that causes timeouts to
be incorrectly handled when attempting to open a socket.  I ran across this
problem when a timeout that was supposed to be ten seconds was taking over
two minutes to time out.  We're using version 3.0RC3 in our build but the
logic looks to be the same in HEAD.

Here's a snippet of the code as it exists now.  The intention is to generate
a series of increasingly longer timeouts until the total requested timeout
has been exhausted.  However the timeout code is not checking against the
accumulated total time but rather against the length of the final timeout in
the series.  The resulting timeout is therefore the sum of this and all
preceding timeouts.

00760         if (ret < 0 && (errno == EINPROGRESS || errno == EALREADY ||
00761                         errno == EAGAIN) && (connect_loop < timeout) )
{
00762                 smb_msleep(connect_loop);
00763                 connect_loop += increment;
00764                 if (increment < 250) {
00765                         /* After 8 rounds we end up at a max of 255
msec */
00766                         increment *= 1.5;
00767                 }
00768                 goto connect_again;
00769         }

I've generated a patch for our build to change the code to this (below).
Note the addition of the 'totalTime' variable, declared above and
initialized to zero.

699         if (ret < 0 && (errno == EINPROGRESS || errno == EALREADY ||
700                         errno == EAGAIN) && (totalTime < timeout) ) {
701                 totalTime += connect_loop;
702                 msleep(connect_loop);
703                 connect_loop += increment;
704                 if(connect_loop+totalTime > timeout)
705                 {
706                         connect_loop = timeout-totalTime;
707                 }
708
709                 if (increment < 250) {
710                         /* After 8 rounds we end up at a max of 255 msec
*/
711                         increment *= 1.5;
712                 }
713                 goto connect_again;

After this patch the connect attempt does timeout at the specified time,
i.e. it seems to work, but please let me know if you spot any errors or
potential side-effects of this change.  Otherwise I think this is a
legitimate bug that should be fixed in HEAD.

Thanks,
Joe Meadows
Snap Appliance