Fix connection resets during firewall sync #807
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For very busy tcp connections there is a small possibility to receive a TCP RST during the iptables sync. A default `REJECT` rule is chronologically added before the allow-`RELATED,ESTABLISHED` rule for ingress and egress connections. In between of the creation of these two rules a connection reset can happen for already established connections. This commits swaps the order of rule insertion.
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good catch @djboris9 thanks for your PR Changes LGTM |
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For very busy tcp connections there is a small possibility to receive
a TCP RST during the iptables sync. It happens only when
--run-firewall=trueis set.In function
NetworkPolicyController.syncPodFirewallChainsa defaultREJECTrule is chronologically added before the accept-
RELATED,ESTABLISHEDrule for ingress andegress connections. In between of the creation of these two rules a connection reset can happen for already established connections.
The solution is to add the allow-
RELATED,ESTABLISHEDrule before theREJECTandjumps to this iptables chain. I see no reason the
REJECTrule is inserted before theACCEPTrule,but maybe I miss something.