portmap: flush UDP conntrack on DEL to avoid hostPort blackhole - #1277
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locker95 wants to merge 1 commit into
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portmap: flush UDP conntrack on DEL to avoid hostPort blackhole#1277locker95 wants to merge 1 commit into
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cmdAdd already deletes stale UDP conntrack entries after installing DNAT rules so a replacement pod with a new IP is not blackholed. cmdDel only tore down the iptables/nftables rules and left conntrack alone. That breaks the common case of flipping a pod to hostNetwork:true on the same hostPort: DEL removes the NAT mapping, but leftover UDP conntrack still steers packets at the gone container IP. Flush on DEL the same way ADD does (best-effort; failures are logged only). Fixes containernetworking#1190 Signed-off-by: Dean Chen <862469039@qq.com>
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Summary
cmdAddalready flushes stale UDP conntrack entries after installing DNAT rules (so a replacement pod with a new IP is not blackholed).cmdDelonly tore down the iptables/nftables rules and left conntrack alone.That breaks flipping a pod to
hostNetwork: trueon the same hostPort: DEL removes the NAT mapping, but leftover UDP conntrack still steers packets at the gone container IP. Traffic to the hostPort blackholes until the entries expire.This makes DEL flush UDP conntrack the same way ADD does (best-effort; failures are logged only).
Test plan
deletePortmapStaleConnectionsis a no-op for TCP-only / empty mappingsFixes #1190