[Winpcap-users] only when ethereal is ON

[Umesh Chandra Sahoo]

Hi Gianluca

I tried some experiment to validate your told things.

In my module I inserted below lines for testing.




unsigned char *packet_data[4];
int ctr = 0;
while(((res = pcap_next_ex( fp, &header, &packet_data[ctr])) >= 0) &
(ctr < 4)){
	printf("\n\n @#@#@#@# [%d].Umesh DBG pkt_data_addr[%u] ,
pkt_data_value[%c] \n", ctr, packet_data[0], 
		 packet_data[0][0]);
	ctr++;
}
pcap_close(fp);
printf("\n\n AFTER PCAP CLOSE.Umesh DBG pkt_data_addr[%u],
pkt_data_value[%c] \n", 
	   packet_data[0], packet_data[0][0]); 


-->In the while loop I called pcap_next_ex() 4 times. So my expectation
is:- packet_data[0] will show different value once since the previous
memory for packet_data[0] was freed while calling the wile loop for
second time. 

--> but I am getting the same address value.
--> If that memory freed and also by chance it shows the same memory
allocated then the value of the packet_data (i.e. packet_data[0][0])
should have some unpredictable value.
--> But I got the same value for packet_data(i.e packet_data[0][0])

--> But the print after the pcap_close(fp) shows some unpredictable
value for packet_data(i.e packet_data[0][0]). 

So I got confirmation upon your second point. 

Dear can you give me any example which can proof your 1st time.
I am asking for the proof since I need to convince all my management
group.


Waitin 4 ur reply
Umesh



-----Original Message-----
From: winpcap-users-bounces at winpcap.org
[mailto:winpcap-users-bounces at winpcap.org] On Behalf Of Gianluca Varenni
Sent: Monday, July 07, 2008 9:19 PM
To: winpcap-users at winpcap.org
Subject: Re: [Winpcap-users] only when ethereal is ON

Hi,

the pointers returned by pcap_next_ex must NOT be released, and they are

valid until
- the next call to pcap_next_ex/pcap_loop/pcap_dispatch
- you close the capture instance of pcap_close

(whatever happens first)

Have a nice day
GV

----- Original Message ----- 
From: "Umesh Chandra Sahoo" <USahoo at ixiacom.com>
To: <winpcap-users at winpcap.org>
Sent: Monday, July 07, 2008 6:44 AM
Subject: [Winpcap-users] only when ethereal is ON


> Hi,
> Can any one tell me how to clear the memory taken by pcap_next_ex().
> --> What is the lifespan of that variable
> lifespan of that variable
>
>
> --> Is that ponter automaticallyreleases?
>
> Regards
> Umesh
>
>
>
> _______________________________________________
> Winpcap-users mailing list
> Winpcap-users at winpcap.org
> https://www.winpcap.org/mailman/listinfo/winpcap-users 

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