Computer Science 881
                               Quiz 2        Name _________________

 1. Which of the following best characterizes a "shared" sk_buff.

    a. Multiple struct sk_buff's        b. A single struct sk_buff
       point to a single kmalloc'd         points to multiple kmalloc'd
       buffer area                         buffer areas

    c. Multiple entities hold valid
       pointers to a single struct
       sk_buff

 2. Which of the following best characterizes a "cloned" sk_buff.

    a. Multiple struct sk_buff's        b. A single struct sk_buff
       point to a single kmalloc'd         points to multiple kmalloc'd
       buffer area                         buffer areas

    c. Multiple entities hold valid
       pointers to a single struct
       sk_buff

 3. Describe consisely and precisely how "sharing" and "cloning" of
    an sk_buff affect the "users" and the "dataref" elements. (No
    effect is a legal but not necessarily correct answer).

    a new entity shares an sk_buff

       users -



       dataref -



    an sk_buff is cloned

       users -



       dataref -





 4. When a process has an excessive amount of send buffer space allocated
    it may have to go to sleep in:
    static long sock_wait_for_wmem(struct sock * sk, long timeo)
    Describe precisely and consisely the chain of events that will cause
    it to wake up.










5. Answer I, D, or N depending upon whether the specified function Increases,
    Decreases, or has no effect on sk_buff <tailroom>.

    ___ a. skb_reserve()

    ___ b. skb_put()

    ___ c. skb_pull()

 6. Diagram the chain of pointers from the "current" task_struct pointer to
    the inode.










 7. During a UDP connect operation

   a. If the socket is not already    b. Any existing bind status is
      bound inet_autobind() is           reset to null
      called to bind it.

   c. The bind status is not
      altered.

 8. During a UDP bind operation

   a. If the socket is not already    b. Any existing connection is
      connected inet_autoconn() is       reset to null.
      called to connect it.

   c. The connection status is not
      altered.


 9. a. For a UDP struct sock  what is the difference in the use of saddr
       and rcv_saddr elements?

       1 - saddr

       2 - rcv_saddr

    b. Which (if either) could (correctly) be set to 0 during normal operation.



10. If you fail to provide a disconnect function in your protocol, how
    can a hacker cause your system to crash?





11. Suppose that the value of the udp_port_rover in udp_v4_get_port() is 0x9ACD
    and that this queue is selected but it is not empty. If port 0x9ACD is
    found already in use what will be the next port number tested.