Setting TOS via sendmsg

From: Alex Kiernan
Date: Mon Aug 08 2005 - 07:04:24 EST

I'm playing with L2TPNS ( - its
an LNS done in software. Its approach is to receive packets via a tun
device, encapsulate them in userland and then push them onto a LAC
using sendto.

I need to copy the TOS from the packets it receives into the header of
the encapsulated packet, but I can't see any way of doing that (short
of calling setsockopt for every packet).

So my thought was to change the kernel so that you can pass in IP_TOS
to sendmsg to specify a per-packet TOS.

Does this sound like the right way to approach it?

Alex Kiernan
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