libosmogsm: (re)introduce gsm48_push_l3hdr()
There was gsm0480_l3hdr_push() declared in a header file, but
not exposed in 'libosmogsm.map'. Furthermore, for some reason
it was a part of GSM 04.80 API, what is not actually correct.
Let's rename this symbol, and properly expose it as a part of
the GSM 04.08 API. Also, let's introduce an auxiliary wrapper
for messages, where the transaction identifier is required
(see GSM 04.07, section 11.2.3.1.2).
Change-Id: I8a045efe8335d83fcbe8d43eb180972e3b1d9dda
diff --git a/src/gsm/gsm48.c b/src/gsm/gsm48.c
index b4892de..136b937 100644
--- a/src/gsm/gsm48.c
+++ b/src/gsm/gsm48.c
@@ -1024,4 +1024,24 @@
{ 0, NULL }
};
+/*! Wrap a given \ref msg with \ref gsm48_hdr structure
+ * \param[out] msg A message to be wrapped
+ * \param[in] pdisc GSM TS 04.07 protocol discriminator 1/2,
+ * sub-pdisc, trans_id or skip_ind 1/2,
+ * see section 11.2.3.1 for details
+ * \param[in] msg_type GSM TS 04.08 message type
+ * @return pointer to pushed header within \ref msg
+ */
+struct gsm48_hdr *gsm48_push_l3hdr(struct msgb *msg,
+ uint8_t pdisc, uint8_t msg_type)
+{
+ struct gsm48_hdr *gh;
+
+ gh = (struct gsm48_hdr *) msgb_push(msg, sizeof(*gh));
+ gh->proto_discr = pdisc;
+ gh->msg_type = msg_type;
+
+ return gh;
+}
+
/*! @} */