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Problem Report 2007 Details

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Report 2007 Actions

    Problem Report Number 2007
    Submitter's Classification Test Suite problem
    State Resolved
    Resolution Test Suite Deficiency (TSD)
    Problem Resolution ID TSD.X.0999
    Raised 1998-04-30 08:00
    Updated 2003-03-13 08:00
    Published 1998-05-06 08:00
    Product Standard Transport Service XTI V2
    Certification Program The Open Brand certification program
    Test Suite VST version 5.2.3
    Test Identification XTI.os/cots/accept 22
    Problem Summary TSDT5.001 This failure was first seen in VST5.2.3A, (i.e. the patch 'A' that was released for VST 5.2.3.) and has been acknowledged by vst_support. The observed behaviour is permitted by XNS Issue 5. A quote ...
    Problem Text
    This failure was first seen in VST5.2.3A, (i.e. the patch 'A' that was released
    for VST 5.2.3.) and has been acknowledged by vst_support.

    The observed behaviour is permitted by XNS Issue 5. A quote from the Errors
    section of t_accept(), Page 55, XNS Issue 5 follows.

    " [TBADSEQ] .... or a valid sequence number was specified, but the
    connection request was aborted by the peer. In the latter
    case, its T_DISCONNECT event will be received on the listening
    endpoint . "

    This is a change from the behaviour specified in XNS Issue 4. In XNS Issue 4,
    t_accept() is specified to return -1 and set t_errno to [TLOOK], if there are
    any incoming T_LISTEN or T_DISCONNECT events. This behaviour was relaxed in
    XNS Issue 5, since there is no need for t_accept() to fail due to an unrelated
    incoming T_LISTEN or T_DISCONNECT. However in this test case, the incoming
    T_DISCONNECT is not an unrelated event. It is a direct cancellation of the
    incoming connection request, that the test tries to t_accept(). The sequence
    number in the 'sequence' field of the t_call parameter specified in the
    t_accept() call is identical to the sequence number of the incoming
    T_DISCONNECT, and is no longer recognized as valid, in the internal queue of
    connections waiting acceptance. This results in the t_accept() call failing
    and setting t_errno to [TBADSEQ].

    It should also be noted that t_accept() can fail and set t_errno to [TBADSEQ]
    even in XNS 4 implementations, under certain conditions described below.
    Asynchrony in Streams framework, or parallelism introduced by Symmetric
    MultiProcessing kernels, can induce a race condition where T_DISCON_IND has
    been processed in the transport provider, but has not reached the Stream head
    yet and hence is not yet visible to t_accept() library code.

    XNS Issue 5 now acknowledges this [TBADSEQ] error, as can be seen in the Errors
    Section of t_accept(), and is quoted above. The VST test suite does not stress
    implementations in such a manner so as to exhibit the above race condition.
    But applications that handle a high rate of connection establishments have been
    observed to exhibit this behaviour in XNS 4 implementations.

    The test expects t_accept() to either succeed and return 0, or fail and
    return -1 and set t_errno to [TLOOK]. It should also allow the case where
    t_errno is set to [TBADSEQ] as allowed by XNS Issue 5.
    Test Output
    ************************************************************************
    /tset/XTI.os/cots/accept/T.accept 22 Failed

    Test Description:
    If the implementation supports a connection-oriented transport service
    other than ISO class 2 and ISO class 3:
    When a T_DISCONNECT event that requires immediate attention has
    occurred on fd, then t_accept() returns (int)-1, sets t_errno to
    TLOOK, and the states of the endpoints fd and resfd are not
    changed.
    Note: in UNIX98 test mode the t_accept() call may succeed instead of
    producing a TLOOK error.

    Test Strategy:
    VERIFY that the transport service is of type T_COTS or T_COTS_ORD
    MASTER:
    OBTAIN an endpoint in T_INCON state using provsetup()
    OPEN a second endpoint using t_open()
    INITIALISE second endpoint using u_provinit()
    SLAVE:
    GENERATE T_DISCONNECT event on master using discon_ev_s()
    MASTER:
    WAIT for a T_DISCONNECT event on the endpoint using wait_event()
    ACCEPT connection using t_accept() with resfd as second endpoint
    VERIFY that t_accept() returned -1 and set t_errno to TLOOK
    VERIFY that t_look() returns T_DISCONNECT
    VERIFY that the states of the endpoints have not changed

    Test Information:
    t_accept() on TCP endpoint
    TERRNO VALUES: expected: 9 (TLOOK), observed: 7 (TBADSEQ)

    ************************************************************************

    Review Information

    Review Type TSMA Review
    Start Date null
    Completed null
    Status Complete
    Review Recommendation No Resolution Given
    Review Response
    This is accepted as a Test Suite Defiency and it is recommended that a
    waiver is granted.

    Review Type SA Review
    Start Date null
    Completed null
    Status Complete
    Review Resolution Test Suite Deficiency (TSD)
    Review Conclusion
    This is an agreed Test Suite Deficiency.

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