jim gotti

Ok. Ill try to only post the pertinent info.

import java.net.*; import java.io.*; public class traceroute { static private final String IP = "#.#.#.#"; static private final int PORT = 3000; static private DatagramSocket clientSocket; static private DatagramPacket datagramIn; static private InetAddress serverAddress, clientAddress; static private int hostIP, i1, i2, i3, i4; public static void main(String args[]) { try { if(args.length < 1) { System.out.println("Input : destination address"); return; } System.out.println("\n Traceroute Server IP : "+IP" Port : "+PORT); System.out.println("-------------------------------------------\n"); hostIP = getIPInt(InteAddress.getByName(args[0].getAddress()); serverAddress = InetAddress.getByName(IP); clientSocket = new DatagramSocket(PORT); byte ttl = 1; NetworkMessage outMsg = getMessage(hostIP, ttl), inMsg; byte[] data = new byte[36]; datagramIn = new DatagramPacket(data, 36); for(int i=1; ttl < 255; i++, ttl++) { outMsg.ipHeader.ttl = ttl; clientSocket.send(new DatagramPacket(outMsg.getBytes(), outMsg.getBytes().length, serverAddress, PORT)); clientSocket.receive(datagramIn); byte[] tf = getBuffer(datagramIn.getData(), datagramIn.getOffset(), datagramIn.getLength()); inMsg = getMessageFromBuf(tf); byte[] buf = getIPBuff(inMsg.ipHeader.saddr); i1 = (int)(buf[3] & 0xff); i2 = (int)(buf[2] & 0xff); i3 = (int)(buf[1] & 0xff); i4 = (int)(buf[0] & 0xff); if ( inMsg.icmpHdr.type==Icmp.Hdr.ICMP_ECHOREPLY ) { //check to see if packet arrived to destination System.out.println("Step "+i+" IP addr is "+i1+"."+i2+"."+i3+"."+i4); break; } if ( inMsg.icmpHdr.type==Icmp.Hdr.TIMXCEED ) { //ttl = 0 System.out.println("Step "+i+" IP addr is "+i1+"."+i2+"."+i3+"."+i4); } else { System.out.println("Step "+i+" * Ip addr is "+i1+"."+i2+"."+i3+"."+i4); } }//end for }//end try catch(IOException e) { e.printStackTrace(); } }//end main /*************************************************************/ static byte[] getbuffer(byte[] buff, int offset, int length) { byte[] retbuff = new byte[length-6]; for (int i =0; i < length-6; i++) { retBuff[i] = buff[offset + i + 6]; } return retBuff; } /************************************************************ ****to print the incoming buffer for testing***************** ************************************************************/ static void printBuf(byte[] buff) { for(int i=0; i<buff.length; i++) { System.out.println(i+ ":"+ buff[i]+ " "); } } static NetworkMessage getMessage(int ip, byte ttl) throws IOException { NetworkMessage nm = new NetworkMessage(); nm.ipHeader.IHL = 5; nm.ipHeader.version = 4; nm.ipHeader.tos = 0; nm.ipHeader.tot_len = 30; nm.ipHeader.id = 11 nm.ipHeader.flags = 0; nm.ipHeader.frag_off = 0; nm.ipHeader.ttl = ttl; nm.ipHeader.protocol = IPheader.IPPROTO_ICMP; nm.ipHeader.checksum = 0; nm.ipHeader.saddr = getIPInt(serverAddress.getAddress()); nm.ipHeader.daddr = ip; nm.icmpHdr.type = 8; nm.icmpHdr.code = 0; nm.icmpHdr.id = 11; nm.icmpHdr.sequence = 0; return nm; }//end getMessage static NetworkMessag getMessageFromBuf(byte[] buf) throws IOEXception { NetworkMessage msg = new NetworkMessage(); msg.set(buf); return msg; } static int getIPInt(byte[] val) throws IOException { int i = 0 byte[] buf = new byte[4]; buf[0] = val[3]; buf[1] = val[2]; buf[2] = val[1]; buf[3] = val[0]; return (new DataInputStream(new ByteArrayInputStream(buf))).readInt(); } static byte[] getIPBuff(int val) { byte[] buf = new byte[4]; buf[0] = (byte)val; buf[0] = (byte)((val>>>8)); buf[0] = (byte)((val>>>16)); buf[0] = (byte)((val>>>24)); return buf; }

excuse any typos, I am not currently at home where I can compile to see if this work, but this is more or less the client I wrote. There are 2 other classes, IPheader, NetworkMessage and IcmpHdr that take care of the header values.
Hope this helps any. I can post the server code, if someone feels it's needed, but it's all in C, and to be honest, it's damn near greek to me(the TA wrote the server, not the class).

Thanks for any feedback you can offer.

Hello folks. I am working on a traceroute program for a networking course at my uni. The project has been nothing but a hair pulling experience, from the coding front, to the admin and 'rights' front.

We developed a java client, that sends a server(written in C) a datagram(UDP), the server sends it off to the net, gets a message back, then the server converts it back so java is happy and we get our output.
The server has been 'acting' up to say the least from the get go, but supposedly others in my class *HAVE* received successful traces. I have not.

Below I will post my output. I will be blocking out the IPs address, not that it matters much, but there are actualy numbers where you see #'s.

From the very first hop, I am receiving type 3 code 3 ICMP messages. And then type 3 code 5's after that. No matter which router my trace hits, the SECOND one is *always* repeated in a sort of loop , which i have to cancel out of .

Here is my output. Any sort of light anyone may be able to shed on this I appreciate. Thing is, I've been crazy over this, and I really do not want to do more work if it is indeed not my program that is borked, but is the server or the network I can attaching to.

The only odd thing I notice is, I the first line(under the dashed line) of the output, I printed the source address to make sure I am getting the right one(of the C server) and it is...however it is preceded by a "/". I cannot figure out how or why this is there, but could that somehow be messing up my program(i do not see how, but i am grasping at straws here trying to figure out what is going on)

> java traceroute www.cnn.com

Traceroute Server IP : #.#.#.# Port : 3000
----------------------------------------------------

/#.#.#.#
message sent type = 8
message sent code = 0
message sent ttl = 1
message received type = 3
message received code = 3
Step 1 * IP addr is #.#.#.#
message sent type = 8
message sent code = 0
message sent ttl = 2
message received type = 3
message received code = 5
Step 2 * IP addr is #.#.#.#
message sent type = 8
message sent code = 0
message sent ttl = 3
message received type = 3
message received code = 5
Step 3 * IP addr is #.#.#.#
message sent type = 8
message sent code = 0
message sent ttl = 4
^Cmessage received type = 3
message received code = 5
Step 4 * IP addr is #.#.#.#


The IP address for step 2+ are all the same.

Quote by Jesse:
"Now that the market has been improving"

They are? I was under the impression of the complete opposite with no real major turn around in sight. Actually, I have been in a major funk thinking that I am killing myself (newborn, working full time, part time CS, trying to be mr family man) drudging through my current CS degree for nothing in the end (mainly no job security)....so please, if this statement is true, enlighten me!

Quote by Jesse:
"I really want to jump back into programming / developing"

based on this sentence alone, personally I dont think that pursuing a MS degree in CS will be a waste of your time. As Jeff said, its more or less up to the individual on how they perceive their time and ONLY THEY can put a 'measure' on if it is being wasted or not.

I think Saliya is saying that you would be better off going the business route to make yourself more marketable and well rounded prospect for a company to consider. I agree, to an extent. Going the business route, imo, take you further away from the design aspect of coding and more on the management path. It seems, according to the sentence I quoted above that Jesse really wants to stay on the developer side of the fence.
[ February 26, 2005: Message edited by: jim gotti ]

You can check your credit report(such as equifax) to see if there is a claim against you. If there isn't , personally (and i am not expert either in this area) I wouldnt put it on form.
However, I would be prepared to answer any questions regarding the situation in case someone happen to have it in their records and confront you with it in an interview. Avoid being blindsided.

preface : I recenly went back to college part time and switched over from civil eng to comp sci for a number of reason ranging from money to a challenging major to convenience of schedule of classes(night) and my current job.

Now I am 2 semesters away from completing my degree and am becoming pretty discouraged when I read through these boards about the diminishing number of jobs out there for programmers. I think what topped it off, I forget his name, but it was a guy that interned for MS and Sun and only had two offers for 40k in 18months until he finally got an offer for 65k.

Stories like this really perplex me. I recently bought a house and my wife and I had a little baby girl and my priorities got all scrambled and reorganized where job security is on the tops of my list, as opposed to salary being on top, prior to her birth.

I see so many people posting with such high qualifications, ranging from masters degress, to numerous certifications and are still jobless.

I am currently working and make 'decent' money, but it is not a place where i want to stay for a variety of reasons. However i feel that my B.S. in comp sci come next december will not offer my any oppurtunity to progress in my career in the IT/prog field.

I have considered going into different fields, however i have already changed my major 3 times and cant afford, timewise, to change it again.

Can anyone offer any encouraging words to someone with an uncertain future. I cant be the only undergrad feeling this way, so maybe any advise, words, whathaveyou anyone with experience can offer might shed some light in our soon to be futures.

thanks,

Jim

[ January 30, 2005: Message edited by: jim gotti ]
[ January 30, 2005: Message edited by: jim gotti ]

maybe use of indexOf(String str) will help? from the API...

[ September 02, 2004: Message edited by: jim gotti ]
[ September 02, 2004: Message edited by: jim gotti ]

check out what 'mod' does...for instance, what 4 mod 2 would result in..

once you know this, you will see the light
[ September 01, 2004: Message edited by: jim gotti ]

Mike,
If Java implicitly puts super() call to a 'parent' constructor, why would one even need to put super() in a constructor themselves? Or you never really have to?

hrm, maybe if the inherentence extends down say, 3 levels....and you only want the bottom level class to make a call to the constructor directly above it and not all the way up you would put super()? is that right? so if i put super() there the call will only go up one level?
[ August 28, 2004: Message edited by: jim gotti ]

Im currently starting from scratch to refresh some java having been away for a while.
i was reading over HWS javanotes and came across this blurb, maybe someing can clear it up for me.

If N is an integer variable, then N/100 is an integer, and 1/N is equal to zero for any N greater than one! This fact is a common source of programming errors. You can force the computer to compute a real number as the answer by making one of the operands real: For example, when the computer evaluates 1.0/N, it first converts N to a real number in order to match the type of 1.0, so you get a real number as the answer.

why is 1/N equal to 0 if N > 1? ;where N is an int?

have yet to use it, but VI is shipped with Linux.

thnx for the site Stefan.

Im currently looking into buying a Laptop soonish, however I'd really like to have a dual boot of win (xp or 2k) and linux (redhat fedora) on it.

Ive seen a site (linuxcertified.com, or .org) and they ship out systems with linux installed. however, they are highly priced.

Has anyone had any success in installing redhat on a Dell laptop or offer any suggestions how to go about putting together a laptop that will be able to fully run linux?

thnx

Float.parseFloat(String) may help?


If you need to keep the precision of 3 decimals this thread may help

it should be noted that you do not have to define a constructor for your class as G said..Java will handle it for you. However if you define even one constructor, Java will no longer automatically create that default constructor for you....you are now in charge or handling all of them

so if you want a constructor to define the color of an Apple object, then you MUST write a default constructor as well, even if there is no body to it.


So
public class Apple ( String color; Int numOf; public Apple(String c, Int x) { color = c; numOf = x; }//end constructor public Apple() { this(red, 5); }//end default constructor }//end class

so now in main if you create an apple say
Apple A = new Apple();

it will call the default constructor, which will in turn call the other constructor with the parameters of red and 5.

if you write
Apple B = new Apple(green, 3);

it will call the constructor with the proper parameters, in the case, the other constructor and set the color to green, and number of apples to 3.

here is a quick read on constructors
[ August 21, 2004: Message edited by: jim gotti ]

thnx for the input....off to learn some VI =p