Changes between Initial Version and Version 1 of Ticket #1140, comment 1


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Timestamp:
11/08/18 20:51:04 (3 years ago)
Author:
stipa
Comment:

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  • Ticket #1140, comment 1

    initial v1  
    1 The problem seems to be caused by fragment_frame holding incorrect "extra_frame" value. Initially it is set to 125, which includes max crypto overhead (120).
     1The problem seems to be caused by fragment_frame holding
     2incorrect "extra_frame" value. Initially it is based on
     3max crypto overhead.
    24
    3 After NCP, we adjust extra_frame value in frame (with AES-256-GCM is is 53). This value is used by mss_fixup_dowork(). However resulting packet size exceeds fragment's PAYLOAD_SIZE_DYNAMIC value, which is calculated with too high frame_extra (125) and unneeded fragmentation is performed.
     5After NCP, we adjust extra_frame value in frame and use it in
     6mss_fixup_dowork(). However resulting packet size exceeds
     7fragment size, which is calculated with incorrect
     8fragment_frame->extra_frame. Because fragment size is
     9exceeded, and we perform unneeded fragmentation.
    410
    511As a fix, fragment_frame->frame_extra should be also updated on NCP negotiation.