Support forwarding RIM messages over GTPCv1 EUTRAN<->GERAN

MMEs connect over Gn interface using GTPCv1 towards the SGSN in order to
exchange RIM PDUs by using "RAN Information Relay" GTPCv1 message type.
For more info, see 3GPP TS 29.060 sec 7.5.14.1 "RAN Information Relay"

In order to support it, this commit does the following:

* Uses new libgtp APIs to rx and tx RAN Information Relay messages. The
  same "gsn" object is reused, ie. the local GTPCv1 socket address used
  for exchanging messages against GGSN is reused.
* Adds a new "sgsn_mme_ctx" struct holding information about MMEs
  allowed by the SGSN, each one containing information about the GTP
  address it uses, the in/out routing based on TAI requests, etc. The
  set of MMEs and their config can be set up using new VTY node introduced
  in this commit.
* The RIM related code in SGSN is refactored to allow forwarding from
  and to several types of addresses/interfaces.

Depends: osmo-ggsn.git Change-Id Iea3eb032ccd4aed5187baca7f7719349d76039d4
Depends: libosmocore.git Change-Id I534db7d8bc5ceb19a2a6866f07d5f5c70e456c5c
Related: SYS#5314
Change-Id: I396450b8d8b66595dab8ff7bf41cbf964bb40d93

0 files changed, 0 insertions, 0 deletions