tree 5c9d894e7bb6770ef1f460cf31e0a07c4bfc6884
parent 361488f83f2cd721bc735ad65936320b2571590b
author Harald Welte <laforge@osmocom.org> 1708753864 +0100
committer laforge <laforge@osmocom.org> 1709021282 +0000

Fix critical bug in default TCP keepalive user timeout

It turns out that our calculation of the TCP_USER_TIMEOUT value was
flawed in several ways:

* there should have been parenthesis around the + operator
  (line->keepalive_probe_interval + line->keepalive_idle_timeout) as the
  keepalive_idle_timeout is in seconds, not milli-seconds.

* in the default case, all those values are configured to -1
  (E1INP_USE_DEFAULT). This means we're using
	1000 * -1 * -1 + -1 = 999
  i.e. just below a second which clearly is not enough for a lossy
  satellite or wifi back-haul.

This fixes a regression introduced in Ia7659c209aea0d26eb37d31e771adc91b17ae668
(libosmo-abis >= 1.4.0) when TCP keepalive user timeouts became enabled
by default.

The initial support for TCP_USER_TIMEOUT was merged in
I5e7425958472aa5d758e09bfbefc7d7d37bf6f5f (libosmo-abis >= 0.7.0) but
since TCP keepalives were not yet enabled by default, only users with
explicit TCP keepalive configuration in their config files would be
affected - and then only of the second part of the bug (operator
precedence).

In addition, let's print the actually-used values to the log, helping to
spot unintended values.

Change-Id: Idca24d3e676a45d860d9eec60dc2097d8d87f3bf
Closes: OS#6375
Related: OS#5785, SYS#6801
Fixes: Ia7659c209aea0d26eb37d31e771adc91b17ae668