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    sock: Introduce the SO_PEEK_OFF sock option · ef64a54f
    Pavel Emelyanov 提交于
    This one specifies where to start MSG_PEEK-ing queue data from. When
    set to negative value means that MSG_PEEK works as ususally -- peeks
    from the head of the queue always.
    
    When some bytes are peeked from queue and the peeking offset is non
    negative it is moved forward so that the next peek will return next
    portion of data.
    
    When non-peeking recvmsg occurs and the peeking offset is non negative
    is is moved backward so that the next peek will still peek the proper
    data (i.e. the one that would have been picked if there were no non
    peeking recv in between).
    
    The offset is set using per-proto opteration to let the protocol handle
    the locking issues and to check whether the peeking offset feature is
    supported by the protocol the socket belongs to.
    Signed-off-by: NPavel Emelyanov <xemul@parallels.com>
    Signed-off-by: NDavid S. Miller <davem@davemloft.net>
    ef64a54f
sock.c 66.7 KB