tree 666217e80ab72b8c2fb2ae7c408a4fdb477d004c
parent 28c438845f327f7f022a8adfc966a3670b8c8146
author Harald Welte <laforge@gnumonks.org> 1543495659 +0100
committer Pau Espin Pedrol <pespin@sysmocom.de> 1640181511 +0100

Introduce CRC and FSM for IuUP (user plane) as used in 3G RTP data

Only support for SMpSDU mode is introduced in this commit.

Not supported explicit list:
- Transparent mode
- ATM/AAL2 based Transport layer
- GTP-U based Transport Layer
- Iu Rate Control procedure
- Time Alignment procedure

APIs are provided to allocate the primitives properly inside the related
msgb. This way primitives can be placed in the headroom, leaving the
data part of the msgb for the IuUP payload, hence allowing re-use of the
msgb and 0 copy of IuUP payload when forwarding data over RNL<->TNL.
Since RNL and TNL primitives relu struct osmo_prim_header, which is not
packed, they cannot be set to packed, and hence proper memory alignment
in the msgb must be done to avoid misaligned accesses (Asan errors about
it otherwise).

Related: SYS#5516
Change-Id: Ibe356fa7b1abaca0091e368db8478e79c09c6cb0