[ns] per packet routing

[Srikanth Sundaresan]

 How does per-packet routing occur for UDP traffic? apps/udp.cc has a
 sendmsg method that creates a packet, populates it and sends it -
 through target_->recv(), and the packet is received by
 Classifier::recv(). target_ seems to be either a connector or a node,
 depending on next hop.

 I see that hdr_cmn structure has a next_hop_ but it seems to contain
 -2 when I access it in Classifier::recv().

 My question is, where is the next hop for each packet resolved? Is it
 resolved on a per-packet basis? Does it use the route_ table in
 routing/route.cc?

 Thanks,
 Srikanth