Bug 1936920: networkpolicy: pass traffic through NAT to handle possible tuple collisions #272
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…isions If a pod makes connections to the same destination pod via a service VIP and directly to the pod's IP address, it may be the case that both connections choose the same source port. After the service VIP connection is DNAT-ed to the destination pod's IP address, both connections will have the same 4-tuple. When conntrack processes the second connection's TCP SYN and attempts to commit the conntrack state, the commit fails due to the tuple collision. To prevent the commit failure, make sure SNAT is done on the source port during the commit in case of a collision. The use of a fake "0.0.0.0" address (an undocumented "feature" of OVS that will soon be formalized) ensures that only the source port will be touched if necessary. Note that the packets won't be manipulated if they don't need to be, even though they are passed through NAT. Flow change suggested by Eelco Chaudron and Flavio Leitner Additional fixes by Dan Winship
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@openshift-cherrypick-robot: Bugzilla bug 1910378 has been cloned as Bugzilla bug 1936920. Retitling PR to link against new bug. In response to this:
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@openshift-cherrypick-robot: This pull request references Bugzilla bug 1936920, which is valid. The bug has been moved to the POST state. The bug has been updated to refer to the pull request using the external bug tracker. 6 validation(s) were run on this bug
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/lgtm |
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@danwinship: once the present PR merges, I will cherry-pick it on top of release-4.6 in a new PR and assign it to you. In response to this:
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[APPROVALNOTIFIER] This PR is APPROVED This pull-request has been approved by: danwinship, openshift-cherrypick-robot The full list of commands accepted by this bot can be found here. The pull request process is described here
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/retest Please review the full test history for this PR and help us cut down flakes. |
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/retest Please review the full test history for this PR and help us cut down flakes. |
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@openshift-cherrypick-robot: All pull requests linked via external trackers have merged: Bugzilla bug 1936920 has been moved to the MODIFIED state. In response to this:
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@danwinship: new pull request created: #274 In response to this:
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This is an automated cherry-pick of #269
/assign danwinship