Differential D32668

tcp: The rack stack can incorrectly have an overflow when calculating a burst delay.
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Authored by rrs on Oct 26 2021, 11:47 AM.

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tuexen

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transport

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rG12752978d32b: tcp: The rack stack can incorrectly have an overflow when calculating a burst…

Summary

If the congestion window is very large the fact that we multiply it by 1000 (for microseconds) can
cause the uint32_t to overflow and we incorrectly calculate a very small divisor. This will then
cause the burst timer to be very large when it should be 0. Instead lets make the three variables
uint64_t and avoid the issue.

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Event Timeline

rrs created this revision.Oct 26 2021, 11:47 AM

Herald added 1 blocking reviewer(s): transport. · View Herald TranscriptOct 26 2021, 11:47 AM

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rrs requested review of this revision.Oct 26 2021, 11:47 AM

While where at it, there is a duplicate srtt that should be just one var at the higher scope. Lets fix
that and make the needed casts when comparing to slot. That way we never can get a
confused compiler :)

tuexen accepted this revision.Oct 26 2021, 3:37 PM

This revision is now accepted and ready to land.Oct 26 2021, 3:37 PM

Closed by commit rG12752978d32b: tcp: The rack stack can incorrectly have an overflow when calculating a burst… (authored by rrs). · Explain WhyOct 26 2021, 5:20 PM

This revision was automatically updated to reflect the committed changes.

rrs added a commit: rG12752978d32b: tcp: The rack stack can incorrectly have an overflow when calculating a burst….

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