Function Not Printing To Log File

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I have a log file that runs in the main() of the program. I also have a function that is called within the main(). The fuction works fine and prints to console, the log file works fine as well, however; the return values from the fuction don't print to the log file, is there something specil that I have to do for this to happen? The function.

C++

void decode_tcp(char *_packet)
{
	TCPHEADER *tcp_header = (TCPHEADER *)_packet;
    BYTE flags = ( ntohs(tcp_header->info_ctrl) & 0x003F );
	if ( flags & 0x01 ) // FIN
		printf("\n   FIN " );
		myfile << "\n   FIN " ;
	if ( flags & 0x02 ) // SYN
		printf("\n   SYN " );
		myfile << "\n   SYN " ;
	if ( flags & 0x04 ) // RST
		printf("\n   RST " );
		myfile << "\n   RST " ;
	if ( flags & 0x08 ) // PSH
		printf("\n   PSH " );
		myfile << "\n   PSH " ;
	if ( flags & 0x10 ) // ACK
		printf("\n   ACK " );
		myfile << "\n   ACK " ;
	if ( flags & 0x20 ); // URG
		printf("\n   URG " );
		myfile << "\n   URG " ;
		printf("\n   Sequence Number  : %lu\n", ntohl(tcp_header->seq_number));
		myfile << "\n   Sequence Number  :"<< ntohl(tcp_header->seq_number);
	}

Posted 26-Oct-11 6:17am

Member 7766180

Updated 26-Oct-11 6:18am

v2

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Comments

Richard MacCutchan 26-Oct-11 12:30pm

Which part is not going to the log?

Member 7766180 26-Oct-11 12:33pm

Everything that you see above that starts with myfile...

4 solutions

Solution 1

I don't see anything that Opens / Creates "myfile" or even declares it.

1) if you don't associate a file with the stream, where do you think the output goes?

2) if you don't post the entire relevant code, you won't get any help

Posted 26-Oct-11 6:41am

Chuck O'Toole

Comments

Member 7766180 26-Oct-11 12:50pm

The code from the main().
else // to 0 else
{//IP To 0 Else Open
printf("\n Source IP: %s", ipSrc);
myfile << "\n Source IP:" << ipSrc;
printf("\n Destination IP: %s", ipDest);
myfile << "\n Destination IP:" << ipDest;
////////////////////////////////////////
time_t rawtime;
struct tm * timeinfo;
time ( &rawtime );
timeinfo = localtime ( &rawtime );
printf ("\n %s", asctime (timeinfo) );
myfile << "\n "<< asctime (timeinfo) ;
////////////////////////////////////////////
decode_tcp(&packet[ip_header_size]);
char *_packet;
_packet = &packet[ip_header_size];
TCPHEADER *tcp_header = (TCPHEADER *)_packet;
BYTE flags = ( ntohs(tcp_header->info_ctrl) & 0x003F );

I tried declaring, opening and closing on the function, but it prints it completely seperate from everything else. My guess is that somehow I have to put myfile..... somewhere on the the function in the main() part?

Chuck O'Toole 26-Oct-11 12:54pm

Depends on what the log is for. If it's just going to be a copy ouf the output you print, probably not, you can open it in the beginning of the program, close it just before exit. However, if the log is going to be used as a diagnostic, to note the progress of the program so you can see how far it got before it crashes, then you should always open / write / close. I do it on each line but if there are lots of lines in a group, you can just wrap the group with open / dump stuff / close.
----------------------
Did you change the message that I replied to? Now my message doesn't make sense in the context of the rewritten reply. Don't do that or at least leave the original message there and add to it, not replace the whole thing.

Member 7766180 26-Oct-11 12:59pm

Sorry, you were quicker than I. I shan't do that again! I'm just copying the output of print. I tried declaring, and opening at the very start of main, and closing it just before exit, it prints ecerything but this function.

Chuck O'Toole 26-Oct-11 13:04pm

The code from main that you posted STILL DOES NOT SHOW THE OPENING OF THE FILE. So this is irrevalent too.

Member 7766180 26-Oct-11 13:10pm

The opening...
int main( int _argc, char *_argv[] )
{//Main Open
ofstream myfile;
myfile.open ("C:\\test.txt",ios::out | ios::app);
struct sockaddr_in sock_sniff;
SOCKET sniff_socket = -1;
WSAData sa_data;

Sergey Alexandrovich Kryukov 26-Oct-11 13:03pm

Same thing: looks like a re-post. Is it related to earlier OP's question? Could it be answered there?
--SA

Member 7766180 26-Oct-11 13:05pm

No, this is a different issue. The log prints fine as you suggested. I'm having a new problem of including the results of this function.

Member 7766180 26-Oct-11 13:08pm

This is what I am getting in the console window.
TCP Header:
Source IP: 65.39.148.34
Destination IP: 192.168.1.105
Wed Oct 26 13:06:24 2011

PSH
ACK
URG
Sequence Number : 532047134

The log file is printing all of the flags and sequence numbers seperate from the IP source, etc. In the console window they are together (as shown)

Chuck O'Toole 26-Oct-11 13:11pm

So now are you saying that the log file prints, you just don't like the contents? That is very different than the question you originally posted which implies that the output isn't getting to the log at all. Which is it?

Member 7766180 26-Oct-11 13:16pm

The log file prints fine, it's just not including the flags from the function that I posted. If I declare, open, close on the function itself it prints the flags seperate not with the source, desitination and date it pretains to.

Member 7766180 26-Oct-11 13:24pm

Tried this.
decode_tcp(&packet[ip_header_size]);
myfile << decode_tcp(&packet[ip_header_size]);
getting error on the << it says no operator matches these operands

Chuck O'Toole 26-Oct-11 13:31pm

Oh that just smacks of throwing crap at the wall to see what sticks. 'decode_tcp()' is declared to be 'void' meaining that it doesn't return any results so why would you think there'd be something to print?

Chuck O'Toole 26-Oct-11 13:09pm

Lots of stuff from this guy looks like a re-post of his older stuff because he's debugging some project one step at a time. Each new bug causes him to write yet another question. The only problem there is that he assumes that we will remember all the crap from the previous questions.

Member 7766180 26-Oct-11 13:12pm

Not a guy :)

Chuck O'Toole 26-Oct-11 13:20pm

Can't infer anything from a username like "Member xxxxxx" so you get generic "guy"

Member 7766180 26-Oct-11 13:24pm

Quite allright

Chuck O'Toole 26-Oct-11 13:29pm

Technically, you can't infer anything from my username either as I could have just made it up. I could be wearing a skirt (which, in this day and age, still doesn't imply gender)

Solution 3

This may be of interest:
ACE[^] and the ACE tutorial by Umar Syyid[^]

ACE is mostly used to develop portable and highly efficient networked solutions, and the library comes with a wide range of examples on how to develop networked applications. It also comes with a very flexible logging facility :)

Best regards
Espen Harlinn

Posted 26-Oct-11 8:46am

Espen Harlinn

Updated 26-Oct-11 8:58am

v2

Comments

Member 7766180 26-Oct-11 18:13pm

Thank you, I will check it out.

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Chuck O'Toole · Accepted Answer · 2011-10-26T07:26:00

Solution 2

OK, this is not a new "solution" per se, it's just that there are so many comments in the previous one that I can't follow what "is" is "is not" true anymore.

So, if the original post is to be taken as "exact", why are you not getting compile errors on 'myfile' being undeclared? Your additional comments show the declaration of 'myfile' inside the scope of 'main()' so it should be inaccessible to the function 'decode_tcp()' so you should get compile errors. If you do not get compile errors, then you are not posting the exact code being used and are wasting our time.

If, as you now say, the output is getting to the log file but is in a format you don't like or doesn't match the 'printf' outputs, then post both outputs. I cannot see your terminal from here so I have no idea what you are looking at unless you show it here.

Posted 26-Oct-11 7:26am

Chuck O'Toole

Comments

Member 7766180 26-Oct-11 13:36pm

The Terminal
TCP Header:
Source IP: 174.129.225.194
Destination IP: 192.168.1.105
Wed Oct 26 13:34:57 2011

SYN
ACK
URG
Sequence Number : 676534648

-------------------- // --------------------
TCP Header:
No Action Required:
-------------------- // --------------------
TCP Header:
Source IP: 174.129.225.194
Destination IP: 192.168.1.105
Wed Oct 26 13:35:03 2011

SYN
ACK
URG
Sequence Number : 676534648

Member 7766180 26-Oct-11 13:38pm

The text file..
Source IP:74.217.252.37
Destination IP:192.168.1.105
Wed Oct 26 13:34:54 2011

No Action Required:
Source IP:64.208.138.133
Destination IP:192.168.1.105
Wed Oct 26 13:34:54 2011

Member 7766180 26-Oct-11 13:38pm

As you can see no flags or sequence number.

Member 7766180 26-Oct-11 13:51pm

So if I do this..
void decode_tcp(char *_packet)
{
ofstream myfile;
myfile.open ("C:\\test.txt",ios::out | ios::app);
TCPHEADER *tcp_header = (TCPHEADER *)_packet;
BYTE flags = ( ntohs(tcp_header->info_ctrl) & 0x003F );

if ( flags & 0x01 ) // FIN
printf("\n FIN " );
myfile << "\n FIN " <<( flags & 0x01 ) ;
if ( flags & 0x02 ) // SYN
printf("\n SYN " );
myfile << "\n SYN " <<( flags & 0x02 );
if ( flags & 0x04 ) // RST
printf("\n RST " );
myfile << "\n RST " <<( flags & 0x04 );
if ( flags & 0x08 ) // PSH
printf("\n PSH " );
myfile << "\n PSH " <<( flags & 0x08 );
if ( flags & 0x10 ) // ACK
printf("\n ACK " );
myfile << "\n ACK " <<( flags & 0x010 );
if ( flags & 0x20 ); // URG
printf("\n URG " );
myfile << "\n URG " <<( flags & 0x020 );
printf("\n Sequence Number : %lu\n", ntohl(tcp_header->seq_number));
myfile << "\n Sequence Number :"<< ntohl(tcp_header->seq_number);
myfile.close();
}

Member 7766180 26-Oct-11 13:52pm

I get this...
Source IP:50.22.100.250
Destination IP:192.168.1.105
Wed Oct 26 13:48:39 2011

No Action Required:
No Action Required:
Source IP:50.22.100.250
Destination IP:192.168.1.105
Wed Oct 26 13:48:39 2011

No Action Required:
No Action Required:
No Action Required:
No Action Required:
Source IP:50.22.10
FIN 0
SYN 2
RST 0
PSH 0
ACK 16
URG 0
Sequence Number :724588489
FIN 0
SYN 0
RST 0
PSH 0
ACK 16
URG 0
Sequence Number :725704959
FIN 0
SYN 0
RST 0
PSH 8
ACK 16
URG 0
Sequence Number :725704959
FIN 1

Member 7766180 26-Oct-11 13:53pm

They are printed seperately, not together.

Chuck O'Toole 26-Oct-11 14:01pm

You still haven't answered the question about why you don't get compile errors when you don't declare 'myfile' inside 'decode_tcp()'. If you code compiles, then you have something called 'myfile' scoped so that 'decode_tcp()' can find it. You also show 'myfile' scoped inside the 'main()' function. How many places do you have this declared? I'm willing to bet $5 that you have a third declaration scoped in the global variables / module level and that file isn't 'open()' so your code compiles but the 'myfile<<' statements are going into something we fondly call 'the bit bucket', into space.

Member 7766180 26-Oct-11 14:05pm

I have it declared in main() and in decode_tcp().

Chuck O'Toole 26-Oct-11 14:08pm

Yes, I see that in this example BUT what happens when you do not declare or open / close it in 'decode_tcp()'? iostream thingies do not throw exceptions unless you tell it to and you are not checking for any errors so things look like they work, when in fact, nothing is working. You either need to check for errors or enable exceptions my setting 'myfile.exceptions ( ifstream::failbit | ifstream::badbit );' after declaring it.

Member 7766180 26-Oct-11 14:09pm

BINGO....I removed "ofstream myfile;" from both main() and decode_tcp(), put it up above with all of the other stuff. #includes..etc. and it works!
Thank you so much Chuck!

Chuck O'Toole 26-Oct-11 14:12pm

Fine. Because it compiled when you didn't have it in 'decode_tcp()', I surmise that you always had one declared at that level in the first place. But that's neither here nor there, it works now so we can end this.

Chuck O'Toole 26-Oct-11 14:13pm

It would be nice it you upvoted and/or accepted one of these solutions for your question

Member 7766180 26-Oct-11 14:16pm

Needed a second. It's done.

Richard MacCutchan · Accepted Answer · 2011-10-26T10:58:00

Solution 4

Do you notice what is wrong with these lines,

C++

if ( flags & 0x01 ) // FIN
    printf("\n   FIN " );
myfile << "\n   FIN " ;

once the indentation has been corrected?
May I suggest you always use braces to bracket the target of if, do, while etc.

Posted 26-Oct-11 10:58am

Richard MacCutchan

Comments

Chuck O'Toole 26-Oct-11 17:25pm

Good one, I didn't see that, I guess I just added the braces to match the indent :)

Richard MacCutchan 26-Oct-11 18:45pm

I missed it first time round as well.

Member 7766180 26-Oct-11 19:48pm

Thanks Richard. Well, well, well. It seems that this problem is not solved. It's printing all of the flags, all of the time. Not just the ones that are being reflected in printf. So maybe these are the wrong lines to do the myfile on?

Member 7766180 26-Oct-11 22:17pm

Thanks Richard I added the brackets and now it prints when needed.
Also, One other thinh occasionaly I get this garble stuff, what could that be?

ACK
Sequence Number: 41183825
»ìtjQ*GPúð¢
Source IP:207.46.15.253
Destination IP:192.168.1.105
Wed Oct 26 22:12:45 2011

ACK
Sequence Number: 41185285
»ìtp*GPúðKš
No Action Required:
Source IP:207.46.15.253
Destination IP:192.168.1.105
Wed Oct 26 22:12:45 2011

PSH
ACK
Sequence Number: 41186745
»ìtu¹*GPúðˆü

Richard MacCutchan 27-Oct-11 4:55am

Looking at your modified code below, I cannot see any reason for the garbage characters. Take a look around the next block where it prints the Source and Destination values.

Member 7766180 26-Oct-11 22:19pm

The corrected code///

void decode_tcp(char *_packet)
{
TCPHEADER *tcp_header = (TCPHEADER *)_packet;
BYTE flags = ( ntohs(tcp_header->info_ctrl) & 0x003F );

if ( flags & 0x01 ) // FIN
{
printf("\n FIN " );
myfile << "\n FIN " ;
}
if ( flags & 0x02 ) // SYN
{
printf("\n SYN " );
myfile << "\n SYN " ;
}
if ( flags & 0x04 ) // RST
{
printf("\n RST " );
myfile << "\n RST " ;
}
if ( flags & 0x08 ) // PSH
{
printf("\n PSH " );
myfile << "\n PSH " ;
}
if ( flags & 0x10 ) // ACK
{
printf("\n ACK " );
myfile << "\n ACK " ;
}
if ( flags & 0x20 ) // URG
{
printf("\n URG " );
myfile << "\n URG " ;
}
printf("\n Sequence Number : %lu\n", ntohl(tcp_header->seq_number));
myfile << "\n Sequence Number: "<< ntohl(tcp_header->seq_number);
myfile << "\n ";
}