3 files changed, 170 insertions, 1 deletions
diff --git a/src/codec/Makefile.am b/src/codec/Makefile.am
index b522d43a..c9d7a228 100644
--- a/src/codec/Makefile.am
+++ b/src/codec/Makefile.am
@@ -13,6 +13,6 @@ endif
 
 lib_LTLIBRARIES = libosmocodec.la
 
-libosmocodec_la_SOURCES = gsm610.c gsm620.c gsm660.c gsm690.c ecu_fr.c
+libosmocodec_la_SOURCES = gsm610.c gsm620.c gsm660.c gsm690.c ecu.c ecu_fr.c
 libosmocodec_la_LDFLAGS = -version-info $(LIBVERSION) -no-undefined
 libosmocodec_la_LIBADD = $(top_builddir)/src/libosmocore.la
diff --git a/src/codec/ecu.c b/src/codec/ecu.c
new file mode 100644
index 00000000..db7148ce
--- /dev/null
+++ b/src/codec/ecu.c
@@ -0,0 +1,118 @@
+/* Core infrastructure for ECU implementations */
+
+/* (C) 2019 by Harald Welte <laforge@gnumonks.org>
+ *
+ * All Rights Reserved
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ */
+
+/* As the developer and copyright holder of the related code, I hereby
+ * state that any ECU implementation using 'struct osmo_ecu_ops' and
+ * registering with the 'osmo_ecu_register()' function shall not be
+ * considered as a derivative work under any applicable copyright law;
+ * the copyleft terms of GPLv2 shall hence not apply to any such ECU
+ * implementation.
+ *
+ * The intent of the above exception is to allow anyone to combine third
+ * party Error Concealment Unit implementations with libosmocodec.
+ * including but not limited to such published by ETSI.
+ *
+ *   -- Harald Welte <laforge@gnumonks.org> on August 1, 2019.
+ */
+
+#include <string.h>
+#include <errno.h>
+
+#include <osmocom/codec/ecu.h>
+#include <osmocom/core/talloc.h>
+
+static const struct osmo_ecu_ops *g_ecu_ops[_NUM_OSMO_ECU_CODECS];
+
+/***********************************************************************
+ * high-level API for users
+ ***********************************************************************/
+
+/*! initialize an ECU instance for given codec.
+ *  \param[in] ctx talloc context from which to allocate
+ *  \parma[in] codec codec for which to initialize/create ECU */
+struct osmo_ecu_state *osmo_ecu_init(void *ctx, enum osmo_ecu_codec codec)
+{
+	if (codec >= ARRAY_SIZE(g_ecu_ops))
+		return NULL;
+	if (!g_ecu_ops[codec] || !g_ecu_ops[codec]->init)
+		return NULL;
+	return g_ecu_ops[codec]->init(ctx, codec);
+}
+
+/*! destroy an ECU instance */
+void osmo_ecu_destroy(struct osmo_ecu_state *st)
+{
+	if (st->codec >= ARRAY_SIZE(g_ecu_ops))
+		return;
+	if (!g_ecu_ops[st->codec])
+		return;
+
+	if (!g_ecu_ops[st->codec]->destroy)
+		talloc_free(st);
+	else
+		g_ecu_ops[st->codec]->destroy(st);
+}
+
+/*! process a received frame a substitute/erroneous frame.
+ *  \param[in] st  ECU state/instance on which to operate
+ *  \param[in] bfi Bad Frame Indication
+ *  \param[in] frame received codec frame to be processed
+ *  \param[in] frame_bytes number of bytes available in frame */
+int osmo_ecu_frame_in(struct osmo_ecu_state *st, bool bfi,
+                      const uint8_t *frame, unsigned int frame_bytes)
+{
+	if (st->codec >= ARRAY_SIZE(g_ecu_ops))
+		return -EINVAL;
+	if (!g_ecu_ops[st->codec])
+		return -EBUSY;
+	return g_ecu_ops[st->codec]->frame_in(st, bfi, frame, frame_bytes);
+}
+
+/*! generate output data for a substitute/erroneous frame.
+ *  \param[in] st ECU state/instance on which to operate
+ *  \param[out] frame_out buffer for generated output frame
+ *  \return number of bytes written to frame_out; negative on error */
+int osmo_ecu_frame_out(struct osmo_ecu_state *st, uint8_t *frame_out)
+{
+	if (st->codec >= ARRAY_SIZE(g_ecu_ops))
+		return -EINVAL;
+	if (!g_ecu_ops[st->codec])
+		return -EBUSY;
+	return g_ecu_ops[st->codec]->frame_out(st, frame_out);
+}
+
+/***********************************************************************
+ * low-level API for ECU implementations
+ ***********************************************************************/
+
+/*! register an ECU implementation for a given codec */
+int osmo_ecu_register(const struct osmo_ecu_ops *ops, enum osmo_ecu_codec codec)
+{
+	if (codec >= ARRAY_SIZE(g_ecu_ops))
+		return -EINVAL;
+	if (g_ecu_ops[codec])
+		return -EBUSY;
+
+	g_ecu_ops[codec] = ops;
+
+	return 0;
+}
diff --git a/src/codec/ecu_fr.c b/src/codec/ecu_fr.c
index ef42ea9f..4545172a 100644
--- a/src/codec/ecu_fr.c
+++ b/src/codec/ecu_fr.c
@@ -164,3 +164,54 @@ int osmo_ecu_fr_conceal(struct osmo_ecu_fr_state *state, uint8_t *frame)
 
 	return 0;
 }
+
+/***********************************************************************
+ * Integration with ECU core
+ ***********************************************************************/
+
+static struct osmo_ecu_state *ecu_fr_init(void *ctx, enum osmo_ecu_codec codec)
+{
+	struct osmo_ecu_state *st;
+	size_t size = sizeof(*st) + sizeof(struct osmo_ecu_fr_state);
+
+	st = talloc_named_const(ctx, size, "ecu_state_FR");
+	if (!st)
+		return NULL;
+
+	memset(st, 0, size);
+	st->codec = codec;
+
+	return st;
+}
+
+static int ecu_fr_frame_in(struct osmo_ecu_state *st, bool bfi, const uint8_t *frame,
+			   unsigned int frame_bytes)
+{
+	struct osmo_ecu_fr_state *fr = (struct osmo_ecu_fr_state *) &st->data;
+	if (bfi)
+		return 0;
+
+	osmo_ecu_fr_reset(fr, frame);
+	return 0;
+}
+
+static int ecu_fr_frame_out(struct osmo_ecu_state *st, uint8_t *frame_out)
+{
+	struct osmo_ecu_fr_state *fr = (struct osmo_ecu_fr_state *) &st->data;
+
+	if (osmo_ecu_fr_conceal(fr, frame_out) == 0)
+		return GSM_FR_BYTES;
+	else
+		return -1;
+}
+
+static const struct osmo_ecu_ops osmo_ecu_ops_fr = {
+	.init = ecu_fr_init,
+	.frame_in = ecu_fr_frame_in,
+	.frame_out = ecu_fr_frame_out,
+};
+
+static __attribute__((constructor)) void on_dso_load_ecu_fr(void)
+{
+	osmo_ecu_register(&osmo_ecu_ops_fr, OSMO_ECU_CODEC_FR);
+}