Computer Science 853
                            Quiz 4             Name_______________________


1. Under precisely what condition will a call to sys_sendto()
   result in the calling process being forced to sleep without
   passing the packet on to the IP layer?






2. Moving the struct sockaddr_in to kernel space is done in the

   a. socket sublayer              b. PF_INET sublayer

   c. transport protocol


3. If a send operation is initiated on an unbound socket an autobind

   a. is not necessary             b. is done in the socket sublayer

   c. is done in the PF_INET       d. is done in the transport protocol
      sublayer

4. Precisely why is it NECESSARY to process the msghdr and/or connected
   sock info BEFORE allocating the struct sk_buff.












5. For a non-connected UDP socket a transmission attempt will be rejected
   if which of the following is 0

   a. dest port                    b. dest IP address

   c. if either a. or b. is        d. even if both are zero
      0 the transmission will         the transmission will succeed
      be rejected

6. For a disconnected UDP socket it is necessary to:

   a. call ip_route_output for every packet sent

   b. call ip_route_output only when the route associated
      with the struct sock has become stale or for the first packet
      sent on the socket

7. For a connected UDP socket it is necessary to:

   a. call ip_route_output for every packet sent

   b. call ip_route_output only when the route associated
      with the struct sock has become stale or for the first packet
      sent on the socket

8. The netfilter facility allows firewalls to install hooks that
   inspect packets.  Which best characterizes the normal operation
   of such hooks

    a. the packet is allowed to pass if ANY hook accepts it

    b. the packet is dropped if ANY hook says to drop it

    c. both a. and b. are true


9. Precisely what happens if NO NETFILTERS have been installed and
   a packet is sent?










10. Identify two conditions that will force the "slow path" to be taken
    in ip_build_xmit

    a -



    b -



11. During a UDP sendto operation, the data to be transmitted is
    copied from user space to kernel space

    a. Before the call to             b. During the call to
       ip_build_xmit()                   ip_build_xmit()

    c. After return from ip_build_xmit()

12. Describe the effect of replacing in ip_build_xmit()
        err = NF_HOOK(PF_INET, NF_IP_LOCAL_OUT, skb,
                 NULL, rt->u.dst.dev, output_maybe_reroute);
    with
        err =  skb->dst->output(skb);