tcp: retire sysctl variable functions_inherit_listen_socket_stack

[tuexen]

Summary

The default was true and it is consistent to inherit the TCP function block from the listener as most of the other parameters.

[cc]

This change seems to revert the commit 6134aabe38c8. Is there any behavior change on V_functions_inherit_listen_socket_stack == 0 after this change? Is the TCP function block from the listener changed dynamically once the default stack is changed?

[tuexen]

In D46141#1052082, @cc wrote:

This change seems to revert the commit 6134aabe38c8. Is there any behavior change on V_functions_inherit_listen_socket_stack == 0 after this change? Is the TCP function block from the listener changed dynamically once the default stack is changed?

Changing the default does not change the listener. You always inherit from the listener. So for V_functions_inherit_listen_socket_stack == 0, there is a change.

[peter.lei_ieee.org]

LGTM.
I think for those who want newly accepted connections to use a "new" default stack, there is a mechanism using tcpsso that could be used to (attempt to) change the listening socket's stack so that new connections use that stack. This would need to be run for all desired listening sockets though.

[cc]

In D46141#1052243, @peter.lei_ieee.org wrote:

LGTM.
I think for those who want newly accepted connections to use a "new" default stack, there is a mechanism using tcpsso that could be used to (attempt to) change the listening socket's stack so that new connections use that stack. This would need to be run for all desired listening sockets though.

Thanks for that TCPSSO(8) info as a workaround, then, I am good with this change.

[tuexen]

In D46141#1052477, @cc wrote:

In D46141#1052243, @peter.lei_ieee.org wrote:

LGTM.
I think for those who want newly accepted connections to use a "new" default stack, there is a mechanism using tcpsso that could be used to (attempt to) change the listening socket's stack so that new connections use that stack. This would need to be run for all desired listening sockets though.

Thanks for that TCPSSO(8) info as a workaround, then, I am good with this change.

I added an example to the tcpsso man-page, which describes how to switch the stack of all listening sockets in 2edac5a60a57.