Re: [PATCH] nwfilter: Avoid firewall hole during VM startup by checking rule presence

Upon VM bootstrapping (start,restore,incoming migration) iptablesCreateBaseChainsFW is called and unconditionally deletes and reinserts top-level firewall chain jumps (e.g. INPUT, FORWARD rules). This briefly opens a hole in the firewall, allowing packets through until the insertions complete. This commit ensures that the base chains are only created once per layer (IPV4/IPV6) and checks whether the expected rules already exist using `iptables -C`. If they do, no delete/insert operations are performed. This eliminates the short window where packets could bypass filters during VM lifecycle operations. Signed-off-by: Dion Bosschieter <dionbosschieter(a)gmail.com&gt; --- src/nwfilter/nwfilter_ebiptables_driver.c | 79 ++++++++++++++--------- 1 file changed, 47 insertions(+), 32 deletions(-)