[PATCH libosmocore 3/8] smscb: process Null messages

[Alex Badea]

Pick smscb messages with a sequence-number of "null".  For these,
construct a RSL_MT_SMS_BC_CMD message and send it upstream.

Signed-off-by: Alex Badea <vamposdecampos at gmail.com>
---
 src/gsm/smscb.c |   71 +++++++++++++++++++++++++++++++++++++++++++++++++++---
 1 files changed, 67 insertions(+), 4 deletions(-)

diff --git a/src/gsm/smscb.c b/src/gsm/smscb.c
index a9f38eb..db7f1cc 100644
--- a/src/gsm/smscb.c
+++ b/src/gsm/smscb.c
@@ -28,9 +28,21 @@
 /*! \file smscb.c */
 
 #include <osmocom/gsm/smscb.h>
+#include <osmocom/gsm/rsl.h>
+#include <osmocom/gsm/tlv.h>
+#include <osmocom/gsm/protocol/gsm_04_12.h>
+#include <osmocom/gsm/protocol/gsm_08_58.h>
 #include <osmocom/core/logging.h>
 #include <osmocom/core/msgb.h>
 
+#include <errno.h>
+
+#define SMSCB_ALLOC_SIZE	256
+#define SMSCB_ALLOC_HEADROOM	64
+
+/* Link Protocol Discriminator for SMSCB */
+#define SMSCB_LPD	1
+
 /*! \brief Initialize a SMSCB entity */
 void smscb_init(struct smscb_entity *se)
 {
@@ -48,14 +60,65 @@ void smscb_set_l3(struct smscb_entity *se, smscb_cb_t cb, void *ctx)
 	se->l3_ctx = ctx;
 }
 
+static int rslms_sendmsg(struct msgb *msg, struct smscb_entity *se)
+{
+	if (!se->l3_cb) {
+		msgb_free(msg);
+		return -EIO;
+	}
+	return se->l3_cb(msg, se, se->l3_ctx);
+}
+
+static int smscb_rx_null_msg(struct smscb_entity *se)
+{
+	struct msgb *msg;
+	struct abis_rsl_cchan_hdr *ch;
+	struct rsl_ie_cb_cmd_type cmd_type = {};
+
+	msg = msgb_alloc_headroom(
+		SMSCB_ALLOC_HEADROOM + SMSCB_ALLOC_SIZE,
+		SMSCB_ALLOC_HEADROOM, "smscb_data");
+	if (!msg)
+		return -ENOMEM;
+
+	msg->l2h = msgb_put(msg, sizeof(*ch));
+	ch = (struct abis_rsl_cchan_hdr *) msg->l2h;
+	rsl_init_cchan_hdr(ch, RSL_MT_SMS_BC_CMD);
+	ch->c.msg_discr |= ABIS_RSL_MDISC_TRANSP;
+	/* TODO: we need ->chan_nr from L1: */
+	ch->chan_nr = rsl_enc_chan_nr(RSL_CHAN_SDCCH8_ACCH, 2, 2);
+
+	cmd_type.command = RSL_CB_CMD_TYPE_NULL;
+	msgb_tv_put(msg, RSL_IE_CB_CMD_TYPE, *((uint8_t *) &cmd_type));
+	msgb_tlv_put(msg, RSL_IE_SMSCB_MSG, 0, NULL);
+
+	/*
+	 * TODO: we need ->frame_nr from L1:
+	 * gsm_fn2gsmtime(&tm, ntohl(l1i->frame_nr));
+	 * msgb_tv_put(msg, RSL_IE_SMSCB_CHAN_INDICATOR, !(tm.tc < 4));
+	 */
+
+	return rslms_sendmsg(msg, se);
+}
+
+
+
 /*! \brief Input data from layer 1 */
 int smscb_ph_data_ind(struct smscb_entity *se, struct msgb *msg)
 {
-	uint8_t addr = msg->l2h[0];
-	uint8_t seq = addr & 0x0f;
+	struct gsm412_block_type *bt = (struct gsm412_block_type *) msg->l2h;
+
+	LOGP(DLLAPD, LOGL_NOTICE, "SMSCB: received message: len=%d"
+		" seq=%d lb=%d lpd=%d spare=%d\n",
+		msg->len, bt->seq_nr, bt->lb, bt->lpd, bt->spare);
+
+	if (bt->lpd != SMSCB_LPD) {
+		msgb_free(msg);
+		return -EINVAL;
+	}
 
-	LOGP(DLLAPD, LOGL_NOTICE, "SMSCB: received message: seq=%d len=%d\n",
-		seq, msg->len);
+	if (bt->seq_nr == GSM412_SEQ_NULL_MSG)
+		smscb_rx_null_msg(se);
 
 	msgb_free(msg);
 	return 0;
-- 
1.7.0.4