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SubjectRe: 2.2.13 ISDN funnies
>>>>> "Karsten" == Karsten Keil <> writes:

Karsten> BTW: What about routing, where the needed headroom is
Karsten> realloced ? What I mean: e.g. a eth0 and a syncppp
Karsten> interface. A packet comes from the ethernet, the
Karsten> ethernet devices allocates the skb for it (I think with
Karsten> no additional headroom, because it don't know about the
Karsten> destination of this packet) then it is send to the
Karsten> network stack, which send it to the syncppp device.
Karsten> Which function allocates skb with the right headroom ?

For ip in 2.2.13, re-alloction is done in ip_output.c::ip_queue_xmit()

Karsten> I looked trough the code and don't find a place, where
Karsten> ppp increase the
dev-> hard_header_len for its need, but maybe the ETH_HLEN (14) is
dev-> allways
Karsten> bigger as the ppp headers ?

isdn_ppp.c uses IPPP_MAX_HEADER, which is set to 10 (I looked through the code
and it seems that the largest header which can actually occur in isdn_ppp
will be 9 bytes).


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