Asymmetrically bonding PPP and ethernet?

[Josh Myer]

Hello,

Has anyone managed to bond a PPP connection as an upstream with an
Ethernet connection as a downstream? My ISP requires this (one-way cable),
and i haven't found anything about it, anywhere. Googling for lots of
different possible keywords turns up nothing of pertinence.

I tried iptables, and then tweaking bonding.c, but it's not working very
well. I think it could be made to work, but i'm running into nuances
between ppp and eth at the kernel level.

The problem is thus: A machine connected to a local network via eth0, and
to the cable modem via eth1, and to a ppp provider on ppp0. ppp0 is the
upstream address at 24.216.n.n/32; eth1 is the downstream at
10.0.0.1/24. eth0 is 10.1.0.20/16. If i connect the ppp up and run
ethereal/tcpdump on eth1, then ping a host, i can see the ICMP replies on
eth1. 

I'm currently using 2.4.4, but i don't think anything related to this has
changed much since then.

Thanks in advance for any advice,
--
/jbm, but you can call me Josh. Really, you can.
 "Design may be clever in spurts,
  but evolution never sleeps"
  -- Rob Landley