Messages in this thread | | | Date | Thu, 28 Oct 1999 22:50:49 +0200 | From | Henner Eisen <> | Subject | Re: 2.2.13 ISDN funnies |
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>>>>> "Karsten" == Karsten Keil <kkeil@suse.de> 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).
Henner
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