selftests: netfilter: Run nft_audit.sh in its own netns

JIRA: https://issues.redhat.com/browse/RHEL-9127

This patch is a backport of the following upstream commit:
commit 2e2d9c7
Author: Phil Sutter <[email protected]>
Date:   Fri Oct 13 22:02:24 2023 +0200

    selftests: netfilter: Run nft_audit.sh in its own netns

    Don't mess with the host's firewall ruleset. Since audit logging is not
    per-netns, add an initial delay of a second so other selftests' netns
    cleanups have a chance to finish.

    Fixes: e8dbde5 ("selftests: netfilter: Test nf_tables audit logging")
    Signed-off-by: Phil Sutter <[email protected]>
    Signed-off-by: Florian Westphal <[email protected]>

Signed-off-by: Ricardo Robaina <[email protected]>

Author: rprobaina

tools/testing/selftests/netfilter/nft_audit.sh

@@ -11,6 +11,12 @@ nft --version >/dev/null 2>&1 || {
 	exit $SKIP_RC
 }
 
+# Run everything in a separate network namespace
+[ "${1}" != "run" ] && { unshare -n "${0}" run; exit $?; }
+
+# give other scripts a chance to finish - audit_logread sees all activity
+sleep 1
+
 logfile=$(mktemp)
 rulefile=$(mktemp)
 echo "logging into $logfile"