Urgent:
 - need to verify that static and external variables in iproute2 aren't
   messed up when using tc repeatedly.
 - code is a mess, e.g. there are still too many "extern"s and other
   "private" declarations in the glue code, there's no consistent policy
   on what goes into klink.c and what goes into ksvc.c, etc.
 - filter.pl doesn't take IP options into account

Soon:
 - the timing model should allow for better control over quantization
 - tcsim also sets the (incorrect) length in fragments (need new keyword or
   modifier)
 - should also compute IP, TCP, UDP checksum
 - should compute UDP length
 - should detect IPv6 header and set protocol, etc. accordingly

General:
 - changes to iproute2 are way too instrusive (should gently adapt iproute2)
 - change to sch_generic is too intrusive (should gently adapt sch_generic)
 - header files don't quite reflect a nice structure (should fix most glaring
   mis-uses)
 - non-work-conserving qdiscs that don't set timers won't be served properly
   (this may be considered a feature)
