[GPRS] implement GTP->SNDCP->LLC downlink user-data path

This only works for packets that are small enough to not need
fragmentation at the SNDCP layer (dns queries, ntp and the like).

It requires libgtp built from OpenGGSN dc3744fda045f9fca83de6881176987335a309a8
or later.  Plain 0.90 will NOT work.

Using this version, I could see bi-directional traffic from various
phones going all the way through BTS, OsmoSGSN, OpenGGSN and being routed
to and from the real internet.  Time to celebrate...
3 files changed
tree: b5ff7d78fe3ef7dea7794e3011f4cf7ae298c141
  1. hlrsync/
  2. linux-kernel/
  3. openbsc/
  4. rrlp-ephemeris/
  5. wireshark/