Some selftests need to adjust sysctl settings. In order to be neutral to the system that the test is run on, it is a good practice to change back to the original setting after the test ends. That involves some boilerplate that can be abstracted away.
In patch #1, introduce two functions, sysctl_set() and sysctl_restore(). The former stores the current value of a given setting, and sets a new value. The latter restores the setting to the previously-stored value.
In patch #2, use these wrappers in a number of tests.
Additionally in patch #3, fix a problem in mirror_gre_nh.sh, which neglected to set a sysctl that's crucial for the test to work.
Petr Machata (3): selftests: forwarding: lib: Add sysctl_set(), sysctl_restore() selftests: forwarding: Use sysctl_set(), sysctl_restore() selftests: forwarding: mirror_gre_nh: Unset RP filter
tools/testing/selftests/net/forwarding/lib.sh | 28 ++++++++++++++++------ .../selftests/net/forwarding/mirror_gre_changes.sh | 7 ++---- .../selftests/net/forwarding/mirror_gre_nh.sh | 6 +++++ .../selftests/net/forwarding/router_multipath.sh | 12 ++++------ 4 files changed, 33 insertions(+), 20 deletions(-)