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Old 04-19-2006, 08:21 AM   #1
Registered: Mar 2006
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arp cache entry.............

hello friends,

i have some doubts reggarding the that arp cache.

in the ip_finish_output2( ) the if(hh) checks whether we have arp cache entry or not
then there is a memcpy( ) to copy header to skbuff.

my doubt is

hh->data[16] (hard header) does it contain whole mac ie src, dst, type or ............ only dst mac
and one more thing is why 16 bytes r used ,as
header is only of 14 bytes(right)

waiting for ur reply

thank u,
Old 04-20-2006, 06:33 PM   #2
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The header contains the source mac address (6 bytes), destination mac (6 bytes), and a two byte frame type (0x0806 for arp) making 14 bytes. Not sure why yours are 16?!

You are talking about the ethernet header around an arp packet, right?

Last edited by bulliver; 04-20-2006 at 06:37 PM.
Old 04-22-2006, 03:44 PM   #3
Registered: Mar 2006
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arp cache.............

thanks for the reply,

I am not worried abt what protocol type...(arp ,ip)
(i am not asking abt the ethernet header...)

I just wanted to make sure whether


contains whole mac( ie src mac ,dst mac ,type)....
just destination mac......

the size is 16 because of some memory allignment problems ( i dont know it properly)

Last edited by shrishailnk; 04-22-2006 at 03:46 PM.


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