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Harald Welte 82d8370f62 layer23: fix unaligned store in osmo_send_l1() 
This fixes the following alignment issue uncovered by asan:

l1l2_interface.c:169:7: runtime error: store to misaligned address 0x61600001ab99 for type 'uint16_t', which requires 2 byte alignment
0x61600001ab99: note: pointer points here
 00 00 00  00 00 00 06 0a 01 19 19  40 18 00 07 00 01 03 49  06 15 00 40 01 c0 00 00  00 00 00 00 00
              ^

Change-Id: Ie65b428107d35bac99bc870fdbc4dc509ca2f33c
 		2018-08-11 12:59:30 +00:00
..
include Move from libc random() to osmo_get_rand_id (2nd attempt) 2018-07-23 20:55:45 +01:00
src layer23: fix unaligned store in osmo_send_l1() 2018-08-11 12:59:30 +00:00
.gitignore misc: Ignore two misc application binaries 2011-01-23 11:36:30 +01:00
COPYING Rename 'layer2' program to 'layer23' program 2010-03-03 14:25:21 +01:00
Makefile.am Rename 'layer2' program to 'layer23' program 2010-03-03 14:25:21 +01:00
README add some notes about layer23 architecture 2010-03-03 14:37:21 +01:00
configure.ac layer23: Add --enable-sanitize and --enable-werror configure flags 2018-08-11 12:59:30 +00:00

README 

= OsmocomBB layer23 architecture =

layer23 is an (incomplete) MS-side implementation of the L2 and L3 GSM
protocols as described in GSM TS 04.06, 04.08 and others.

== Interfaces ==

L1 (on the phone) uses the L1CTL protocol to talk with layer23 (on the PC).

L2 (inside layer23) uses the RSLms protocol to talk with the L3 (inside layer23)


=== RSLms ===

RSLms is modeled after the GSM TS 08.58 Radio Subsystem Link protocol.  Despite
being designed for the network side, RSL seems a good match for the L2/L3
interface inside a MS, too.

At least the RLL (Radio Link Layer) part of RSL is 100% as applicable to the MS
side as it is for the ntwork side.

==== Lower interface (L2 to RSLms) ====

Layer2 calls rslms_sendmsg() with a msgb that has the msgb->l2h pointing to a
RSL header (struct abis_rsl_common_hdr).

==== Upper interface (L3 to RSLms) ====

Layer3 calls rslms_recvmsg() with a msgb that has the msgb->l2h pointing to a
RSL header (struct abis_rsl_common_hdr).

There are utility functions like rslms_tx_rll_req() and rslms_tx_rsll_req_l3()
for creating msgb's with the apropriate RSL/RLL headers.


=== LAPDm ===

LAPDm is the GSM TS 04.06 protocol

The lower interface (to L1) is using L1CTL

The upper interface (to L3) is using RSLms