git: DragonFly_RELEASE_5_6 kernel - Change tcp keepalive options from ms to seconds (DISRUPTIVE) (2)

Matthew Dillon dillon at
Tue Jun 25 21:55:22 PDT 2019

commit 106a7748a4ca8d9eda364d2b0102d11d9e0b6368
Author: Matthew Dillon <dillon at>
Date:   Tue Jun 25 21:48:20 2019 -0700

    kernel - Change tcp keepalive options from ms to seconds (DISRUPTIVE) (2)
    * Refactor the code slightly to adopt the same limits and behavior
      as linux.  Instead of capping out we return EINVAL on any out-of-
      bound value.
    * Also note that my history was wrong.  Sephe actually implemented
      these options, not me, and it was in 2011 (8 years ago, not 15+).
      So much for my vague memory!  At the time other operating systems
      used wildly different metrics, and we chose to use milliseconds.
      But in the intervening years it looks like the main systems have
      adopted a 1-second interval.
      In changing our parameters to match, we avoid a lot of pain when
      porting third party applications that use it, particularly chrome.
      But also a few others.
      If we need sub-second parameters in the future we will implement
      new option keywords for it.

Summary of changes:
 sys/netinet/tcp_usrreq.c | 40 ++++++++++++++++------------------------
 1 file changed, 16 insertions(+), 24 deletions(-)

DragonFly BSD source repository

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