There are just too many unknowns in the OP's question for me to be of more help!
Some code would go a long way towards clarifying things!
I think we can both agree upon that!

Network Programming in C is a full 4 hour college level class. So this is not an "its easy, learn it over the weekend subject".

Getting this stuff to work "most of time" is not that hard. The complicated parts all involve these "yeah, but", "what happens if," situations. Perl is a bit different than the C functions.

Without some code, I can't tell what the OP is actually doing.

I looked back and found a Perl version of one my C client readn() routines that reads fixed length packets. Getting a zero byte return is not necessarily an error.

Getting a -1 in C or undef in Perl is an error. My C version just returned the -1 error. Here I sent the USR1 signal to myself just for grins to play around with it. I didn't keep my test report, so I can't prove that this works without some re-testing and having to post much more code. There could very likely be a "hole" in it.

It is completely possible for the "writer" to have already died while stuff is still available for the "reader" to read. I'm not at all sure what this "reset from the server" means - how the client is supposed to learn that and what it is supposed to once it does.

There are various ways to do the reads: blocking/non-blocking and flavors thereof. 

sub readn
{
   my ($socket, $bytes ) = @_;
   my $offset = 0;
   
   my $buf = "";
   while ($offset < $bytes)
   {
      my $nread;
      my $nleft = $bytes-$offset;
      
      $nread = sysread($socket,$buf,$nleft,$offset);

      ## undef is like the -1 C return
      kill 'USR1',$$ unless (defined $nread);  

      last if ($nread ==0);                 ## EOF
      
      $offset += $nread;
   }

   return $buf;
}

[download]

In reply to Re^4: How to monitor TCP Resets using Sockets by Marshall
in thread How to monitor TCP Resets using Sockets by w3ntp

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