hello,
i want to add my own variables with icmp header.
so i modified icmp header and added 2 variables to
make icmp header len is 16 bytes. but when i build
kernel image and boot it and then ping to myself why
am i still getting 8 bytes header i.e. 84 bytes packet
and why not 92 bytes packet?
56 bytes data + 16 bytes icmp header + 20 bytes ip
header = 92 bytes
also ping results shown below takes much time to ping
myself. what gone wrong? how to make it behave like
normal ping?
[root@localhost root]# ping localhost
PING localhost.localdomain (127.0.0.1) 56(84) bytes of
data.
64 bytes from localhost.localdomain (127.0.0.1):
icmp_seq=1 ttl=64 time=1488806
ms
64 bytes from localhost.localdomain (127.0.0.1):
icmp_seq=2 ttl=64 time=1489805
ms
--- localhost.localdomain ping statistics ---
2 packets transmitted, 2 received, 0% packet loss,
time 999ms
rtt min/avg/max/mdev =
1488806.484/1489305.976/1489805.469/500.981 ms
[root@localhost root]#
regards,
parag.
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On Mon, 26 Apr 2004, Parag Nemade wrote:
> hello,
> i want to add my own variables with icmp header.
> so i modified icmp header and added 2 variables to
> make icmp header len is 16 bytes. but when i build
> kernel image and boot it and then ping to myself why
> am i still getting 8 bytes header i.e. 84 bytes packet
> and why not 92 bytes packet?
> 56 bytes data + 16 bytes icmp header + 20 bytes ip
> header = 92 bytes
> also ping results shown below takes much time to ping
> myself. what gone wrong? how to make it behave like
> normal ping?
You don't modify the kernel to make a new ICMP packet!
You modify `ping` or make your own. If you change the
length of the header, it is no longer ICMP. Your
tools will misinterpret what you have.
Cheers,
Dick Johnson
Penguin : Linux version 2.4.26 on an i686 machine (5557.45 BogoMips).
Note 96.31% of all statistics are fiction.