Change in libosmocore[master]: Implement ITU-T I.460 multiplex / demultiplex

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laforge gerrit-no-reply at lists.osmocom.org
Thu May 14 09:46:46 UTC 2020


laforge has uploaded this change for review. ( https://gerrit.osmocom.org/c/libosmocore/+/18247 )


Change subject: Implement ITU-T I.460 multiplex / demultiplex
......................................................................

Implement ITU-T I.460 multiplex / demultiplex

This implements a multiplexer and de-multiplexer for the ITU-T I.460
standard.  The latter covers the transmission of sub-slots of 32/16/8k
inside 64k timeslots.

Change-Id: Id522f06e73b77332b437b7a27e4966872da70eda
---
M include/Makefile.am
A include/osmocom/gsm/i460_mux.h
M src/gsm/Makefile.am
M src/gsm/libosmogsm.map
4 files changed, 88 insertions(+), 1 deletion(-)



  git pull ssh://gerrit.osmocom.org:29418/libosmocore refs/changes/47/18247/1

diff --git a/include/Makefile.am b/include/Makefile.am
index 572c880..456b8ef 100644
--- a/include/Makefile.am
+++ b/include/Makefile.am
@@ -103,6 +103,7 @@
                        osmocom/gsm/gsm_utils.h \
                        osmocom/gsm/gsup.h \
                        osmocom/gsm/gsup_sms.h \
+                       osmocom/gsm/i460_mux.h \
                        osmocom/gsm/ipa.h \
                        osmocom/gsm/lapd_core.h \
                        osmocom/gsm/lapdm.h \
diff --git a/include/osmocom/gsm/i460_mux.h b/include/osmocom/gsm/i460_mux.h
new file mode 100644
index 0000000..759e392
--- /dev/null
+++ b/include/osmocom/gsm/i460_mux.h
@@ -0,0 +1,79 @@
+#pragma once
+#include <stdint.h>
+#include <osmocom/core/bits.h>
+#include <osmocom/core/linuxlist.h>
+#include <osmocom/core/msgb.h>
+
+/* I.460 sub-slot rate */
+enum osmo_i460_rate {
+	OSMO_I460_RATE_NONE,		/* disabled */
+	OSMO_I460_RATE_64k,
+	OSMO_I460_RATE_32k,
+	OSMO_I460_RATE_16k,
+	OSMO_I460_RATE_8k,
+};
+
+typedef void (*out_cb_bits_t)(void *user_data, const ubit_t *bits, unsigned int num_bits);
+typedef void (*out_cb_bytes_t)(void *user_data, const uint8_t *bytes, unsigned int num_bytes);
+
+struct osmo_i460_subchan_demux {
+	/*! bit-buffer for output bits */
+	uint8_t *out_bitbuf;
+	/*! size of out_bitbuf in bytes */
+	unsigned int out_bitbuf_size;
+	/*! offset of next bit to be written in out_bitbuf */
+	unsigned int out_idx;
+	/*! callback to be called once we have received out_bitbuf_size bits */
+	out_cb_bits_t out_cb_bits;
+	out_cb_bytes_t out_cb_bytes;
+	void *user_data;
+};
+
+struct osmo_i460_subchan_mux {
+	/*! list of to-be-transmitted message buffers */
+	struct llist_head tx_queue;
+};
+
+struct osmo_i460_subchan {
+	enum osmo_i460_rate rate;		/* 8/16/32/64k */
+	uint8_t bit_offset;		/* bit offset inside each byte of the B-channel */
+	struct osmo_i460_subchan_demux demux;
+	struct osmo_i460_subchan_mux mux;
+};
+
+struct osmo_i460_timeslot {
+	struct osmo_i460_subchan schan[8];
+};
+
+/*! description of a sub-channel; passed by caller */
+struct osmo_i460_schan_desc {
+	enum osmo_i460_rate rate;
+	uint8_t bit_offset;
+	struct {
+ 		/* size (in bits) of the internal buffer; determines granularity */
+		size_t num_bits;
+ 		/*! call-back function called whenever we received num_bits */
+		out_cb_bits_t out_cb_bits;
+ 		/*! out_cb_bytes call-back function called whenever we received num_bits.
+		 * The user is usually expected to provide either out_cb_bits or out_cb_bytes.  If only
+		 * out_cb_bits is provided, output data will always be provided as unpacked bits;  if only
+		 * out_cb_bytes is provided, output data will always be provided as packet bits (bytes).  If
+		 * both are provided, it is up to the I.460 multiplex to decide if it calls either of the two,
+		 * depending on what can be provided without extra conversion. */
+		out_cb_bytes_t out_cb_bytes;
+ 		/* opaque user data pointer to pass to out_cb */
+		void *user_data;
+	} demux;
+};
+
+void osmo_i460_demux_in(struct osmo_i460_timeslot *ts, const uint8_t *data, size_t data_len);
+
+void osmo_i460_mux_enqueue(struct osmo_i460_subchan *schan, struct msgb *msg);
+int osmo_i460_mux_out(struct osmo_i460_timeslot *ts, uint8_t *out, size_t out_len);
+
+void osmo_i460_ts_init(struct osmo_i460_timeslot *ts);
+
+struct osmo_i460_subchan *
+osmo_i460_subchan_add(void *ctx, struct osmo_i460_timeslot *ts, const struct osmo_i460_schan_desc *chd);
+
+void osmo_i460_subchan_del(struct osmo_i460_subchan *schan);
diff --git a/src/gsm/Makefile.am b/src/gsm/Makefile.am
index 6935eab..eeb1164 100644
--- a/src/gsm/Makefile.am
+++ b/src/gsm/Makefile.am
@@ -32,7 +32,7 @@
 			milenage/milenage.c gan.c ipa.c gsm0341.c apn.c \
 			gsup.c gsup_sms.c gprs_gea.c gsm0503_conv.c oap.c gsm0808_utils.c \
 			gsm23003.c mncc.c bts_features.c oap_client.c \
-			gsm29118.c gsm48_rest_octets.c cbsp.c gsm48049.c
+			gsm29118.c gsm48_rest_octets.c cbsp.c gsm48049.c i460_mux.c
 libgsmint_la_LDFLAGS = -no-undefined
 libgsmint_la_LIBADD = $(top_builddir)/src/libosmocore.la
 
diff --git a/src/gsm/libosmogsm.map b/src/gsm/libosmogsm.map
index 1ff1286..372b0f1 100644
--- a/src/gsm/libosmogsm.map
+++ b/src/gsm/libosmogsm.map
@@ -664,5 +664,12 @@
 osmo_cbsp_recv_buffered;
 osmo_cbsp_errstr;
 
+osmo_i460_demux_in;
+osmo_i460_mux_enqueue;
+osmo_i460_mux_out;
+osmo_i460_subchan_add;
+osmo_i460_subchan_del;
+osmo_i460_ts_init;
+
 local: *;
 };

-- 
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Gerrit-Project: libosmocore
Gerrit-Branch: master
Gerrit-Change-Id: Id522f06e73b77332b437b7a27e4966872da70eda
Gerrit-Change-Number: 18247
Gerrit-PatchSet: 1
Gerrit-Owner: laforge <laforge at osmocom.org>
Gerrit-MessageType: newchange
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