[BPF] send RST to midflow TCP packets from unknown streams #8933
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marvin-tigera
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| iptables.Rule{ | ||
| Match: iptables.Match().MarkMatchesWithMask(tcdefs.MarkSeenFallThrough, tcdefs.MarkSeenFallThroughMask), | ||
| Comment: []string{fmt.Sprintf("%s packets from unknown flows.", d.ruleRenderer.IptablesFilterDenyAction())}, | ||
| Comment: []string{fmt.Sprintf("%s packets from unknown TCP flows.", d.ruleRenderer.IptablesFilterDenyAction())}, |
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| Comment: []string{fmt.Sprintf("%s packets from unknown TCP flows.", d.ruleRenderer.IptablesFilterDenyAction())}, | |
| Comment: []string{fmt.Sprintf("%s packets from unknown non-TCP flows.", d.ruleRenderer.IptablesFilterDenyAction())}, |
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For a smooth switch from iptables to ebpf mode, we do not want to interrupt existing connections. If we see midflow packets, we pass them to the host stack. If the stack can verify that they belong to an existing conntrack, we let them through and we learn the conntrack. We drop the rest. However, there are some situations when we can see a stray TCP packet during ebpf mode, for instance when a pod dies and ECMP kicks in and sends a packet to a different host. If such a packet gets dropped, the end of the connections remains stuck. This change sends an RST to such a stream instead of just dropping the packets so that the end host can break the connection. Fixes projectcalico#8882
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only a single unrelated failure fixed here #8952 |
fasaxc
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Description
Fixes #8882
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