From 5fd4c81c634c3f441d66a01ffde28c5834029004 Mon Sep 17 00:00:00 2001
From: Alexander Couzens <lynxis@fe80.eu>
Date: Wed, 28 Sep 2022 16:22:29 +0200
Subject: [PATCH] gb: add bssgp2_enc_flush_ll encode FLUSH-LL

Change-Id: I76dc3b08a63cfd78c9f7657fb58c2ddfa9b4b7e2
---
 include/osmocom/gprs/gprs_bssgp2.h |  1 +
 src/gb/gprs_bssgp2.c               | 29 +++++++++++++++++++++++++++++
 src/gb/libosmogb.map               |  1 +
 3 files changed, 31 insertions(+)

diff --git a/include/osmocom/gprs/gprs_bssgp2.h b/include/osmocom/gprs/gprs_bssgp2.h
index 3b5b6e823..23312fc2f 100644
--- a/include/osmocom/gprs/gprs_bssgp2.h
+++ b/include/osmocom/gprs/gprs_bssgp2.h
@@ -59,6 +59,7 @@ struct msgb *bssgp2_enc_bvc_reset(uint16_t bvci, enum gprs_bssgp_cause cause,
 struct msgb *bssgp2_enc_bvc_reset_ack(uint16_t bvci, const struct gprs_ra_id *ra_id, uint16_t cell_id,
 				      const uint8_t *feat_bm, const uint8_t *ext_feat_bm);
 
+struct msgb *bssgp2_enc_flush_ll(uint32_t tlli, uint16_t old_bvci, uint16_t *new_bvci, uint16_t *nsei);
 struct msgb *bssgp2_enc_status(uint8_t cause, const uint16_t *bvci, const struct msgb *orig_msg, uint16_t max_pdu_len);
 
 
diff --git a/src/gb/gprs_bssgp2.c b/src/gb/gprs_bssgp2.c
index 8e2ba66ce..104fe08e1 100644
--- a/src/gb/gprs_bssgp2.c
+++ b/src/gb/gprs_bssgp2.c
@@ -349,6 +349,35 @@ struct msgb *bssgp2_enc_fc_bvc(const struct bssgp2_flow_ctrl *fc, enum bssgp_fc_
 	return msg;
 }
 
+/*! Encode BSSGP FLUSH-LL PDU as per TS 48.018 Section 10.4.1.
+ *  \param[in] tlli - the TLLI of the MS
+ *  \param[in] old_bvci BVCI
+ *  \param[in] new_bvci2 optional BVCI - only encoded if non-NULL
+ *  \param[in] nsei optional - only encoded if non-NULL
+ *  \returns encoded PDU or NULL in case of error */
+struct msgb *bssgp2_enc_flush_ll(uint32_t tlli, uint16_t old_bvci,
+				 const uint16_t *new_bvci, const uint16_t *nsei)
+{
+	struct msgb *msg = bssgp_msgb_alloc();
+	struct bssgp_normal_hdr *bgph;
+
+	if (!msg)
+		return NULL;
+
+	bgph = (struct bssgp_normal_hdr *) msgb_put(msg, sizeof(*bgph));
+	bgph->pdu_type = BSSGP_PDUT_FLUSH_LL;
+
+	msgb_tvlv_put_32be(msg, BSSGP_IE_TLLI, tlli);
+	msgb_tvlv_put_16be(msg, BSSGP_IE_BVCI, old_bvci);
+	if (new_bvci)
+		msgb_tvlv_put_16be(msg, BSSGP_IE_BVCI, *new_bvci);
+
+	if (nsei)
+		msgb_tvlv_put_16be(msg, BSSGP_IE_BVCI, *nsei);
+
+	return msg;
+}
+
 /*! Encode a FLOW-CONTROL-BVC-ACK PDU as per TS 48.018 Section 10.4.4.
  *  \param[in] tag the tag IE value to encode
  *  \returns encoded PDU or NULL in case of error */
diff --git a/src/gb/libosmogb.map b/src/gb/libosmogb.map
index ff5b34a23..e02273d91 100644
--- a/src/gb/libosmogb.map
+++ b/src/gb/libosmogb.map
@@ -85,6 +85,7 @@ bssgp2_enc_fc_bvc;
 bssgp2_enc_fc_bvc_ack;
 bssgp2_enc_fc_ms;
 bssgp2_enc_fc_ms_ack;
+bssgp2_enc_flush_ll;
 bssgp2_enc_status;
 
 bssgp_bvc_fsm_alloc_sig_bss;