gsm0808: add knowledge of TW-TS-003 BSSMAP IE

Themyscira Wireless Technical Specification TW-TS-003 adds
a non-standard IE to GSM 08.08 BSSMAP whose purpose is to signal
the use of enhanced RTP payload formats that go against the
stipulations of TS 26.102 (referenced from 48.103 for AoIP),
but allow an IP-based GSM network implementation to mimic
the workings of TDM-based GSM more faithfully.

Spec reference:

https://www.freecalypso.org/specs/tw-ts-003-v010002.txt

Related: OS#6448
Change-Id: Idd6f1838bdc0cd71a2f6357e9b6d8b8fa4f7c46c
---
M include/osmocom/gsm/protocol/gsm_08_08.h
M src/gsm/gsm0808.c
2 files changed, 25 insertions(+), 2 deletions(-)

diff --git a/include/osmocom/gsm/protocol/gsm_08_08.h b/include/osmocom/gsm/protocol/gsm_08_08.h
index 1e211dc..4539656 100644
--- a/include/osmocom/gsm/protocol/gsm_08_08.h
+++ b/include/osmocom/gsm/protocol/gsm_08_08.h
@@ -332,9 +332,10 @@
 	GSM0808_IE_PS_REGISTERED_OPERATOR	= 0x99,
 	GSM0808_IE_CS_REGISTERED_OPERATOR	= 0x9a,
 
-	/* Osmocom extensions: */
+	/* Osmocom and Themyscira extensions: */
 	GSM0808_IE_OSMO_OSMUX_SUPPORT		= 0xf0,
 	GSM0808_IE_OSMO_OSMUX_CID		= 0xf1,
+	GSM0808_IE_THEMWI_RTP_EXTENSIONS	= 0xf2,
 };
 
 /* 3GPP TS 48.008 3.2.3 Signalling Field Element Coding.
diff --git a/src/gsm/gsm0808.c b/src/gsm/gsm0808.c
index 529dbdf..85c2aef 100644
--- a/src/gsm/gsm0808.c
+++ b/src/gsm/gsm0808.c
@@ -2310,9 +2310,10 @@
 		[GSM0808_IE_PS_REGISTERED_OPERATOR]	= { TLV_TYPE_FIXED, 3 },
 		[GSM0808_IE_CS_REGISTERED_OPERATOR]	= { TLV_TYPE_FIXED, 3 },
 
-		/* Osmocom extensions */
+		/* Osmocom and Themyscira extensions */
 		[GSM0808_IE_OSMO_OSMUX_SUPPORT]		= { TLV_TYPE_T },
 		[GSM0808_IE_OSMO_OSMUX_CID]		= { TLV_TYPE_TV },
+		[GSM0808_IE_THEMWI_RTP_EXTENSIONS]	= { TLV_TYPE_TLV },
 	},
 };
 

