CS476/576

Assignment #4

Due Midnight, Wednesday   Nov 21, 2007

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Write two C/UNIX sockets programs with the following descriptions:

NAME

TCPdispatch -   TCP-based Parent dispatches work among children.

UDPdispatch -   UDP-based Parent dispatches work among children.

SYNOPSIS

TCPdispatch <n> <m> <InputFile> <OutputFile>

UDPdispatch <n> <m> <InputFile> <OutputFile>

DESCRIPTION

This is exactly like Assignment #3 but instead of using Pipes for the parent to send data to its children, it uses TCP sockets for TCPdispatch and UDP sockets for UDPdispatch.

Child Process Activities:

This is the same as in Assisgnmnet #3, in addition it Logs a CONNECT record in the ChildrenLog File. The form of this record is:

Ø For TCP:

CONNECT:TCP: i:PID:127.0.0.1:ParentPort#

(e.g., CONNECT:TCP:3:1428:127.0.0.1:57500).

Ø For UDP:

CONNECT:UDP: i:PID:127.0.0.1:ParentPort#

(e.g., CONNECT:UDP:1:3452:127.0.0.1:29432).

NOTE: After the child’s creation, it sends a UDP message (e.g., “HI”) to its parent. When the parent gets this message, it can then finds out the child’s UDP port number.

Parent Process Activities:

This is the same as in Assisgnmnet #3, in addition it Logs an ACCEPT record in the ChildrenLog File. The form of this record is:

Ø For TCP:

ACCEPT:TCP: i:PID:127.0.0.1:ChildPort#

(e.g., ACCEPT:TCP:3:1428:127.0.0.1:34562).

Ø For UDP:

ACCEPT:UDP: i:PID:127.0.0.1:ChildPort#

(e.g., CONNECT:UDP:1:3452:127.0.0.1:53463).

NOTE: this is logged after the parent receives the child’s “HI” message.

The following figure is a general overview of the system:

	OutputFile	ChildrenLog

Please see Dr. wahab’s solutions is at:

http://www.cs.odu.edu/~cs476/fall07/assignments/a4/wahab/

You may use the shell script: check_sh to verify the accuracy of the results.

Examples: they all use InputFile

% TCPdispatch 5 5 InputFile OutputFile

Results:

TCPChildrenLog_5_5

TCPPrent_Log_5_5

TCPcheck_5_5

% UDPdispatch 5 5 InputFile OutputFile

Results:

UDPChildrenLog_5_5

UDPPrent_Log_5_5

UDPcheck_5_5