Project 2: Internet Router Solution

Description

Router Simulation based on Route Table as Generic Hash Table

Educational Objectives: After completing this assignment, the student should be able to accomplish the following:

Describe and explain in detail the concept of hash table

Implement hash tables as vector of lists

Define and implement the ADT Table using a private hash table structure

Define and implement bidirectional iterator class for this implementation of Table Explain the concept of Internet Router and Route Table

Implement a Route Table using the ADT Table (and, in particular, using an implementation using hash tables.

Operational Objectives: Implement the template adaptor classes HashTable<K,T,H> and HashTableIterator<K,T,H>. Design and implement a class RouteTable to be used with the distributed client program iprouter.cpp to simulate the operation of an Internet router.

Deliverables: Four files:

hashtbl.h # contains HashTable<> and HashTableIterator<> template classes (including

implementations)

iptable.h # contains RouteTable class definition and supporting function prototypes

iptable.cpp # contains RouteTable implementations and supporting function implementations

log.txt # your project work log

Procedural Requirements

1. The official development | testing | assessment environment is gnu g++ on the linprog machines.

2. Create and work within a separate subdirectory cop4530/proj2.

3. Do your own work. Variations of this project have been used in previous courses. You are not permitted to seek help from former students or their work products. For this and all other projects, it is a violation of course ethics and the student honor code to use, or attempt to use, code from any source other than that explicitly distributed in the course code library, or to give or receive help on this project from anyone other than the course instruction staff. See Introduction/Work Rules.

4. Begin by copying the entire directory LIB/proj2 into your proj2 directory. Note that there is a subdirectory testfiles that needs to be copied. At this point you should see these files in your directory:

fhtbl.cpp # test harness for hash tables

hasheval.cpp # hash table analyzer

rantable.cpp # random table generator

hashcalc.cpp # hash calculator

hashtbl.start # starting point for hashtbl.h

iprouter.cpp # internet router simulator

iptable.h.start # starting point for iptable.h

iptable.cpp.start # starting point for iptable.cpp

makefile.ht # build hash table project

makefile.ip # build ip router project

proj2submit.sh # submit script

testfiles # directory of test files

Then copy these relevant executables:

LIB/area51/fhtblKISS.x	# fhtbl.x with KISS hash function
LIB/area51/fhtblMM.x	# fhtbl.x with MM hash function
LIB/area51/fhtblSimple.x	# fhtbl.x with Simple hash function / non-prime flag
LIB/area51/hashevalKISS.x	# hash analysis with KISS
LIB/area51/hashevalMM.x	# hash analysis with MM
LIB/area51/hashevalSimple.x # hash analysis with Simple/non-prime
LIB/area51/rantable.x	# random table	generator
LIB/area51/hashcalc.x	# hash function	calculator
LIB/area51/iprouter.x	# sample iprouter executable

Project 2: Internet Router

The executables in area51 are distributed only for your information and experimentation. You will not use these files in your own project, but they will help you understand hashing and hash tables and are very useful in preparing for the final exam. When you have questions about behavior of either hash tables or the router simulation, use these executable to find the answer.

5. You are to define and implement the template classes HashTable<K,T,H> and its associated iterator class HashTableIterator<K,T,H>. In addition you are to design and implement the class RouteTable to be used with the distributed client program iprouter.cpp.

5. File hashtbl.h should contain the definitions and implementations of the template classes HashTable<K,T,H> and HashTableIterator<K,T,H>. Note that a lot of this work is already done in the startup file.

5. File iptable.h should contain the definition of class RouteTable and prototyes of supporting functions.

5. File iptable.cpp should contain implementations of RouteTable methods and supporting functions. Again, the startup files contain all of the boiler plate and some other metods already completed.

5. Two makefiles are supplied: makefile.ht and makefile.ip makefile.ht builds the supporting test infrascrtcure for hash tables, and makefile.ip builds the executable iprouter.x. You can test different targets individually by naming them as an argument to the make command.

5. Submit the assignment using the script proj2submit.sh.

Warning: Submit scripts do not work on the program and linprog servers. Use shell.cs.fsu.edu to submit assignments. If you do not receive the second confirmation with the contents of your assignment, there has been a malfunction.

Code Requirements and Specifications – HashTable and HashTableIterator

1. Implement the HashTable<K,T,H> and HashTableIterator<K,T,H> classes as defined in the file LIB/proj2/hashtbl.start using the implementation plan discussed in the lecture notes.

2. The following are the items that have incomplete implementations in hashtbl.start:

// ADT Table

template <typename K, typename D, class H>

HashTableIterator<K,D,H> HashTable<K,D,H>::Insert (const K& k, const D& d)

{

}

template <typename K, typename D, class H>

bool HashTable<K,D,H>::Remove (const K& k)

{

}

template <typename K, typename D, class H>

bool HashTable<K,D,H>::Retrieve (const K& k, D& d) const

{

}

template <typename K, typename D, class H>

HashTableIterator<K,D,H> HashTable<K,D,H>::Includes (const K& k) const

{

}

// ADT Associative Array

template <typename K, typename D, class H>

D& HashTable<K,D,H>::Get (const K& key)

{

}

template <typename K, typename D, class H>

void HashTable<K,D,H>::Put (const K& key, const D& data)

{

}

template <typename K, typename D, class H>

D& HashTable<K,D,H>::operator[] (const K& key)

Project 2: Internet Router

{

}

// Iterator increment

template <typename K, typename D, class H>

HashTableIterator <K,D,H>& HashTableIterator<K,D,H>::operator ++ ()

{

}

Note that our hash table has both the Table API and the Associative Array API.

3. Place HashTable<K,T,H> and HashTableIterator<K,T,H> in the fsu namespace.

3. For the private data storage use a fsu::Vector < fsu::List < fsu::Entry < KeyType, DataType > > >

object. (This is implied by the definition in hashtbl.start.)

3. Note the the class template Entry<K,T> is optimized to hold entries in tables. It comes complete with appropriately overloaded operators and a hash function class template. Be sure to familiarize yourself with this class template. (Distributed in file LIB/tcpp/entry.h.)

3. Be sure not to change the definition of HashTable<> from that distributed in LIB/proj2/hashtbl.start.

3. Note that HashTableIterator is a ConstIterator type, so that only the const versions of operator * and Retrieve() exist.

3. Place all hash table code, including definitions and implementations for both hash table and hash table iterator, in the file hashtbl.h.

3. Thoroughly test your implementation for correct functionality using the provided test client fthtbl.cpp and tables from tests/tables/ and/or tables generated using rantable.cpp

IP Addressing

There are two ways to represent ip addresses: the 4-number “dot” notation and the 32-bit (4-byte) “number” notation. The dot notation we store as a String object (typedef ipString) and the number notation we store as an unsigned int object (typedef ipNumber). Generally, a router uses ipNumber as its internal representation, while externally across the Internet the ipString representation is used.

The ipString representation consists of four numerical fields separated by (three) dots. For example,

128.186.121.211 is the ip address of a machine in the computer science department. Each numerical field in this address represents a number in the range [0, 255]. (Numbers 256 or greater make an invalid ipString. We also define the zero address 0.0.0.0 as invalid.) This number in turn denotes an 8-bit (one byte) quantity. The four numerical fields, concatenated, represent 32 bits or 4 bytes. This 4-byte number is the internal ipNumber representation. In general, we use hexadecimal (base 16) representation to denote ipNumber objects. The ipNumber representation of the address above is 10000000101110100111100111010011 (bin) = 80BA79D3 (hex).

The ipClass of an ip address is defined in terms of the bits in its ipNumber representation. There are three recognized classes of ipNumbers: A, B, and C. An ipNumber that is not one of these classes is called bad and cannot be used. Class A consists of ipNumbers beginning (on the left) with bit ‘0‘. Class B begins with bits ‘10‘. Class C begins with bits ‘110‘. All other ipNumbers are bad. (Note that bad ipNumbers are not the same as invalid ipStrings.) A good (i.e., not bad) ipNumber contains information in fields called netID and hostID . The ranges of these fields depend on the class, as shown in the following table (numbering the bits from the left, starting with 1):

Class	A:	netID = bits 2..8;				hostID = bits			9..32
Class	B:	netID	=	bits	3..16;	hostID	=	bits	17..32
Class	C:	netID	=	bits	4..24;	hostID	=	bits	25..32

The netID and hostID are full 32 – bit words with the irrelevant bits masked to zero. For example, the address 80BA79D3 is class B with netID = 00BA0000 and hostID = 000079D3. netID and hostID are used by a router to forward messages. We do not express netID and hostID in “dot” notation. The following summarizes the calculations:

ipString	(bin)	128.186.121.211
ipNumber		1000 0000 1011 1010 0111 1001 1101 0011

Project 2: Internet Router
ipNumber	(hex)	8	0	B	B	A	7	9	D	3	= 80BA79D3
ipClass	(bin)	class			1111	1111	0000	0000	0000	0000
netMaskB		0011	1111								= 3FFF0000
netMaskB	(hex)	3	F		F	F	0	0	0	0
netID	(bin)	0000 0000 1011 1010 0000 0000 0000 0000									= 00BA0000
netID	(hex)	0	0		B	A	0	0	0	0
hostMaskB	(bin)	0000	0000		0000	0000	1111	1111	1111	1111	= 0000FFFF
hostMaskB	(hex)	0	0		0	0	F	F	F	F
hostID	(bin)	0000	0000		0000	0000	0111	1001	1101	0011	= 000079D3
hostID	(hex)	0	0		0	0	7	9	D	3

Real Routers

Routers are special- purpose computers that monitor Internet traffic, either rejecting or accepting messages. Accepted messages are forwarded and rejected messages are ignored. For example, the Love Building router run by the Computer Science department rejects incoming messages that are not addressed to a machine in the building, and accepts and forwards messages addressed to one of the machines in the building. It also forwards outgoing messages to another router for further routing. Much of the computation has direct hardware support, enabling speed (bandwidth) to be 1 gigabit. The route tables, in contrast, need to be software tables so that the router can be programmed as both internal and external machine configurations and addresses evolve. Hash tables/maps are the only data structure that guarantees fast enough lookup for today’s high-bandwidth routers.

Code Requirements and Specifications – RouteTable

1. RouteTable Types. You will need the following type definitions:

typedef unsigned int ipNumber;

typedef fsu::String ipString;

enum ipClass

^{ classA, classB, classC, badClass } ;

2. Output operator. Overload operator <<() for type ipClass using the following prototype:

std::ostream& operator << (std::ostream& os, ipClass ipc);

// sends ‘A’, ‘B’, ‘C’, or ‘D’ to os depending on ipClass value

3. RouteTable Public Interface. You will need the following public methods in RouteTable:

void	Load	(const char*	tblfile);
void	Save	(const char*	tblfile);
void	Insert	(const ipString& destination, const ipString& route);
void	Remove	(const ipString& destination);
void	Go	(const char* msgfile, const char* logfile);
void	Clear	();	dumpfile);
void	Dump	(const char*
	RouteTable	(unsigned int	sizeEstimate);
	~RouteTable ();

static ipClass ipInterpret(const ipNumber& address, ipNumber& netID, ipNumber& hostID);

// returns ipClass and sets netID and hostID of address; // if address is badClass, netID and hostID are set to 0.

static ipNumber ipS2ipN (const ipString& S);

// converts ipString to ipNumber, checking for syntax and oversize errors

Go() performs a simulation as described.

Load() and Save() build/save the route table from/to an external file.

Insert() and Remove() are similar to the standard table operations, except that they must translate input from ipString to ipNumber prior to accessing the underlying table.

Go() and Dump() send output to screen when passed a 0 pointer as output file parameter; otherwise all char* parameters are treated as external file names.

Static member functions behave like stand- alone functions with scope limited to the class. These functions should be included in the RouteTable class as static methods.

Project 2: Internet Router

4. Data Structures. Use a HashTable<ipNumber,ipNumber,ipHash> object as the primary data structure supporting the route table.

Note : This object will need to be created dynamically in order to set the number of buckets.

4. Data, Table, and File Format. RouteTable objects use three distinct kinds of files: table files, message files, and log files.

A table file (extension .tbl) consists of pairs of ipNumber (one pair per line) written in hex notation with ‘0’ fill, so that all entries have 8 characters. The Load(filename) method of a RouteTable object reads data from a table file and inserts the data into its internal table. The Save(filename) method writes all data in the internal table to a table file.

The internal table also uses ipNumber representation of addresses.

The ipNumber pairs in a route table are destination and route pairs. The destination is the key, and the route is the data in the table.

When individual entries are inserted, removed, or looked up (via the RouteTable public interface) in the internal table, the external ipString representation is used for input.

The Go() method is the method that simulates a router in operational mode. The incoming internet traffic is simulated by a message file. Each line of the message file can be thought of as a “packet” with a destination and a message body. The result of routing this traffic is recorded in a log file.

Go() should read message packets (lines) one at a time from a message file and write the disposition of these message packets to a log file. For each message packet (line of the message file), the router (1) reads the destination address and converts it to ipNumber form; (2) rejects the message packet if the ipClass is bad; (3) looks up the packet destination in the internal table; (4) if not found, rejects the packet;

4. 5. routes the packet using the netID and hostID of the route retrieved from the table; (6) writes the disposition of the message packet to the log file.

The message file (extension .msg) consists of two strings per line. The first string of the packet (line) is an ip address in dot notation (intended to be the destination of the message) and the second is a message ID (simulating the body or content of a real message). Each line of this file represents one “message packet” coming in to the router.

The log file (extension .log ) should contain one line for each message packet in the message file. The log entry for a message should begin with the message ID, followed by the ipNumber of the destination (8-digit hex), then the ipClass and the routing information (netID and hostID) for the message.

6. Running a Simulation. Your RouteTable should work with the supplied client program iprouter.cpp, which simulates the operation of a router.

Hints

Start NOW on HashTable<K,T,H> and test it. Then start on RouteTable.

A client test program for HashTable<K,T,H> is distributed as tests/fthtbl.cpp. This will be compiled directly from the course library when you enter the command “make fthtbl.x“. However, you should copy the source code into your project directory and read the code.

The directory tests/tables contains test table files. A random table file generation program is supplied as tests/rantable.cpp.

You may find the following typedef statements (made inside the private portion of RouteTable) very helpful in making your code readable, to yourself and others:

typedef fsu::Entry < ipNumber, ipNumber > EntryType;

typedef fsu::HashTable < ipNumber, ipNumber, ipHash > TableType;

The client program iprouter.cpp is distributed in the proj2 directory, along with a selection of table files.

You can assume that the table files contain only good ipNumbers, since they are all created by a properly operating router.

Project 2: Internet Router

You can assume that incoming messages will have valid dot-notation strings as destinations, but you cannot assume that incoming message destination strings denote good ipClasses.

You cannot assume that user entries are either valid or good.

To read and write the hex codes correctly, you will need (1) to manipulate the std::ios:: flags hex and uppercase for both input and output streams; (2) to set the fill character using the manipulator std::setfill(); and (3) to use the std::setw() manipulator to set the column width in output.

The hash function class ipHash may be defined and implemented as follows:

// in file iptable.h

class ipHash

^{ public:

_{} ;} unsigned int operator () (const ipNumber&) const;

// in file iptable.cpp

#include <hash.h>

unsigned int ipHash::operator () (const ipNumber& ipn) const ^{_} return hashfunction::KISS (ipn);

You need a hash function object to instantiate a hash table object.

You need only one private data item in RouteTable: a pointer to a HashTable<> object.

The following aspects of your solution will be tested:

1. Completeness and correctness of your HashTable<> design and implementation.

2. Correct/failsafe file handling

3. Correct/failsafe table building/saving

4. Correct/failsafe handling of user input

5. Correct/failsafe translation of ipStrings to ipNumbers

6. Correct/failsafe decoding of ipNumbers (class, etc)

7. Correct/failsafe routing (table lookup)

Sample executables fthtbl.x and iprouter.x are supplied LIB/area51. Sample tables and a table building program are supplied in LIB/tests/tables. Sample route table and message files are supplied in LIB/proj2.

Test Bench: A test suite and script are supplied in the directory proj2/testfiles. It is not advised that you run this test until you have done your own testing, otherwise you may be overwhelmed. But once you think you have the project complete, do the following: create a directory ~/cop4530/proj2/testbench and copy the script ~cop4530p/spring10/proj2/testfiles/check into that directory. Then change permissions on check to executable. Be sure to read the script first to be sure that there are no name conflicts which could destroy your proj2 files. To be safe, also make a backup copy of all of your critical files (such as the deliverables!) Then execute the script and hold on.

file:///C|/Users/Desktop/Documents/FSU/COP%204530/proj2/Project%202%20Internet%20Router.htm[4/13/2012 10:17:00 AM]