Bug 2218123

This bug was initially created as a copy of Bug #2217177

I am copying this bug because Fedora is affected as well.

Description of problem:

  cups_rresvport() doesn't reserve ports less than 512; however,
  lpd_queue() continues decrementing the port number to 0.  This leads
  to delays of ~511 seconds once all ports between 512-1023 are
  exhausted.  Even when ports become available, lpd_queue() still tries
  calling cups_rresvport() with port numbers less than 512, waiting one
  second between each call.

Version-Release number of selected component (if applicable):

  cups-2.3.3op2-16.el9.x86_64

How reproducible:

  100%

Steps to Reproduce:

  1. Create a print queue that sends jobs to an LPD print device.
  2. Submit ~550 jobs to the LPD printer.

  After ~511 jobs have been transfered via LPD, the lpd backend will
  block waiting for reserved ports to move out of TIME_WAIT and become
  available for re-use.

Actual results:

  Even after reserved ports become available for re-use, the lpd backend
  waits ~511 seconds before continuing to send jobs to the LPD print
  device.

Expected results:

  After reserved ports become available for re-use, the lpd backend
  should immediately continue sending jobs to the LPD print device.

Additional info:

  Upstream PR to fix the issue:
  
  Fix delays printing to lpd when reserved ports are exhausted
  https://github.com/OpenPrinting/cups/pull/741