Assignment 10
		  cs494-unp
		   revised: 11/7/99

Assigned: October 26, 1999
Due: December 3, 1999  6:00pm

Objective:  multicast UDP

Points: 25

Description:

   Develop a multicast terminal chat program that takes as
   optional arguments a multicast host address and optionally
   a port number. The program should print the host address
   and port that it is using.  After bind and setsockopt() the program
   should send a message like
     <dunigan@thdsun signing ON>
   using getuid(), getpwuid() and gethostname().  The program should
   create a child process to continuously read from the socket and write
   to the terminal, prefacing each received line with the
   hostname of the sender (e.g.):
      msr.epm.ornl.gov: hi how are you
   The parent process should continuously read a line from
   stdin (gets()) and send it out the socket until the user types ctrl-d.
   Then the parent process should send a sign-off message, e.g.,
     <dunigan@thdsun signing OFF>
   and kill the child and exit.
   (Or you can use select() instead of fork(), e.g., modify assignment 5.)
   You'll probably want to IP_MULTICAST_LOOP enabled (the default,
   I think), so multiple copies running on the same machine will
   hear each other (and themselves).

   This application will have to be built and tested on 
   multicast-capable machines, e.g. any of Solaris critters.

   Be certain the IP_MULTICAST_TTL socket option is 1.

   For the default host address and port use:

#define HADDR "224.7.8.9"
#define PORT 7654
   
   that way, we can all "chat" together ....

   Finally, from deneb or altair, use tcpdump (with -x and whatever)
   to capture one of your multicast packets.  Include the tcpdump
   output in results file.

   Your submitted output should demonstrate that you tested
   your program with at least three clients in the chat session.

  Optional: please indicate amount of time required to complete assignment.

  Use ~dunigan/cs494-unp/494submit to submit your source files and output.
  See http://www.cs.utk.edu/~dunigan/cs494-unp/policy.txt