tree 22a304e575b509fc6208d401919b146f1792997c
parent 1c963eb97d1ae80f7cd9c98f922b52da4aca6915
author Vadim Yanitskiy <vyanitskiy@sysmocom.de> 1590745116 +0700
committer laforge <laforge@osmocom.org> 1592481264 +0000

abis_nm: fix ARFCN list encoding in Set Channel Attributes

3GPP TS 12.21 defines coding of 'ARFCN List' attribute as follows:

  +---------------------------+--------------------+
  | Attribute Identifier      | 1st octet          |
  +---------------------------+--------------------+
  | Length                    | 2-3 octets         |
  +---------------------------+--------------------+
  | ARFCN1                    | 4-5 octets         |
  +---------------------------+--------------------+
  | ...                       | ...                |
  +---------------------------+--------------------+
  | ARFCNn                    | (n * 2 - 3) octets |
  +---------------------------+--------------------+

so this is basically TL16V, where L16 is the length of V.

In the Siemens dialect of OML coding rules are different though:

  +---------------------------+--------------------+
  | Attribute Identifier      | 1st octet          |
  +---------------------------+--------------------+
  | ARFCN count               | 2nd octet          |
  +---------------------------+--------------------+
  | ARFCN1                    | 4-5 octets         |
  +---------------------------+--------------------+
  | ...                       | ...                |
  +---------------------------+--------------------+
  | ARFCNn                    | (n * 2 - 2) octets |
  +---------------------------+--------------------+

so this is TCV, where C is the amount of ARFCNs in V.

This change fixes encoding of 'ARFCN List' for other dialects,
in particular encoding of the 'Length' field (1 vs 2 octets).
I verified the results in Wireshark (generic 3GPP TS 12.21
and ip.access dialect), everything looks good.

Change-Id: Iec1826f55459ac8e9355328a1a6bb0949874db60
Related: OS#4545